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  Subjects -> BIOLOGY (Total: 3134 journals)
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BIOTECHNOLOGY (236 journals)                  1 2 | Last

Showing 1 - 200 of 237 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 8)
Advanced Biomedical Research     Open Access  
Advances in Bioscience and Biotechnology     Open Access   (Followers: 14)
Advances in Genetic Engineering & Biotechnology     Hybrid Journal   (Followers: 8)
African Journal of Biotechnology     Open Access   (Followers: 6)
Algal Research     Partially Free   (Followers: 10)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 64)
American Journal of Bioinformatics Research     Open Access   (Followers: 7)
American Journal of Polymer Science     Open Access   (Followers: 31)
Anadolu University Journal of Science and Technology : C Life Sciences and Biotechnology     Open Access  
Animal Biotechnology     Hybrid Journal   (Followers: 8)
Annales des Sciences Agronomiques     Full-text available via subscription  
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43)
Applied Bioenergy     Open Access  
Applied Biosafety     Hybrid Journal  
Applied Food Biotechnology     Open Access   (Followers: 3)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 63)
Applied Mycology and Biotechnology     Full-text available via subscription   (Followers: 4)
Arthroplasty Today     Open Access   (Followers: 1)
Artificial Cells, Nanomedicine and Biotechnology     Hybrid Journal   (Followers: 1)
Asia Pacific Biotech News     Hybrid Journal   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Pacific Journal of Tropical Biomedicine     Open Access   (Followers: 2)
Australasian Biotechnology     Full-text available via subscription   (Followers: 1)
Banat's Journal of Biotechnology     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 5)
Bio-Algorithms and Med-Systems     Hybrid Journal   (Followers: 2)
Bio-Research     Full-text available via subscription   (Followers: 2)
Bioactive Materials     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 4)
Biocybernetics and Biological Engineering     Full-text available via subscription   (Followers: 5)
Bioethics UPdate     Hybrid Journal  
Biofuels     Hybrid Journal   (Followers: 11)
Biofuels Engineering     Open Access   (Followers: 1)
Biological & Pharmaceutical Bulletin     Full-text available via subscription   (Followers: 4)
Biological Cybernetics     Hybrid Journal   (Followers: 10)
Biomarkers and Genomic Medicine     Open Access   (Followers: 3)
Biomarkers in Drug Development     Partially Free   (Followers: 1)
Biomaterials Research     Open Access   (Followers: 4)
BioMed Research International     Open Access   (Followers: 4)
Biomédica     Open Access  
Biomedical and Biotechnology Research Journal     Open Access  
Biomedical Engineering Research     Open Access   (Followers: 6)
Biomedical glasses     Open Access  
Biomedical Reports     Full-text available via subscription  
BioMedicine     Open Access  
Biomedika     Open Access  
Bioprinting     Hybrid Journal   (Followers: 1)
Bioresource Technology Reports     Hybrid Journal   (Followers: 1)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 21)
Biosimilars     Open Access   (Followers: 1)
Biosurface and Biotribology     Open Access  
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
BioTechniques : The International Journal of Life Science Methods     Full-text available via subscription   (Followers: 28)
Biotechnologia Acta     Open Access   (Followers: 1)
Biotechnologie, Agronomie, Société et Environnement     Open Access   (Followers: 2)
Biotechnology     Open Access   (Followers: 5)
Biotechnology & Biotechnological Equipment     Open Access   (Followers: 4)
Biotechnology Advances     Hybrid Journal   (Followers: 33)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 155)
Biotechnology and Bioprocess Engineering     Hybrid Journal   (Followers: 5)
Biotechnology and Genetic Engineering Reviews     Hybrid Journal   (Followers: 13)
Biotechnology and Health Sciences     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access   (Followers: 1)
Biotechnology Annual Review     Full-text available via subscription   (Followers: 5)
Biotechnology for Biofuels     Open Access   (Followers: 10)
Biotechnology Frontier     Open Access   (Followers: 2)
Biotechnology Journal     Hybrid Journal   (Followers: 16)
Biotechnology Law Report     Hybrid Journal   (Followers: 4)
Biotechnology Letters     Hybrid Journal   (Followers: 34)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Biotechnology Reports     Open Access  
Biotechnology Research International     Open Access   (Followers: 1)
Biotechnology Techniques     Hybrid Journal   (Followers: 10)
Biotecnología Aplicada     Open Access  
Bioteknologi (Biotechnological Studies)     Open Access  
Biotribology     Hybrid Journal   (Followers: 1)
BMC Biotechnology     Open Access   (Followers: 16)
Cell Biology and Development     Open Access  
Chinese Journal of Agricultural Biotechnology     Full-text available via subscription   (Followers: 4)
Communications in Mathematical Biology and Neuroscience     Open Access  
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computer Methods and Programs in Biomedicine     Hybrid Journal   (Followers: 8)
Contributions to Tobacco Research     Open Access   (Followers: 2)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biotechnology     Hybrid Journal   (Followers: 20)
Crop Breeding and Applied Biotechnology     Open Access   (Followers: 3)
Current Bionanotechnology     Hybrid Journal  
Current Biotechnology     Hybrid Journal   (Followers: 4)
Current Opinion in Biomedical Engineering     Hybrid Journal   (Followers: 1)
Current Opinion in Biotechnology     Hybrid Journal   (Followers: 56)
Current Pharmaceutical Biotechnology     Hybrid Journal   (Followers: 9)
Current Research in Bioinformatics     Open Access   (Followers: 12)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Current trends in Biotechnology and Pharmacy     Open Access   (Followers: 8)
EBioMedicine     Open Access  
Electronic Journal of Biotechnology     Open Access  
Entomologia Generalis     Full-text available via subscription  
Environmental Science : Processes & Impacts     Full-text available via subscription   (Followers: 4)
Experimental Biology and Medicine     Hybrid Journal   (Followers: 3)
Folia Medica Indonesiana     Open Access  
Food Bioscience     Hybrid Journal  
Food Biotechnology     Hybrid Journal   (Followers: 9)
Food Science and Biotechnology     Hybrid Journal   (Followers: 8)
Frontiers in Bioengineering and Biotechnology     Open Access   (Followers: 6)
Frontiers in Systems Biology     Open Access   (Followers: 2)
Fungal Biology and Biotechnology     Open Access   (Followers: 2)
GM Crops and Food: Biotechnology in Agriculture and the Food Chain     Full-text available via subscription   (Followers: 1)
GSTF Journal of BioSciences     Open Access  
HAYATI Journal of Biosciences     Open Access  
Horticulture, Environment, and Biotechnology     Hybrid Journal   (Followers: 11)
IEEE Transactions on Molecular, Biological and Multi-Scale Communications     Hybrid Journal   (Followers: 1)
IET Nanobiotechnology     Hybrid Journal   (Followers: 2)
IIOAB Letters     Open Access  
IN VIVO     Full-text available via subscription   (Followers: 4)
Indian Journal of Biotechnology (IJBT)     Open Access   (Followers: 2)
Indonesia Journal of Biomedical Science     Open Access   (Followers: 2)
Indonesian Journal of Biotechnology     Open Access   (Followers: 1)
Industrial Biotechnology     Hybrid Journal   (Followers: 18)
International Biomechanics     Open Access  
International Journal of Bioinformatics Research and Applications     Hybrid Journal   (Followers: 13)
International Journal of Biomechatronics and Biomedical Robotics     Hybrid Journal   (Followers: 4)
International Journal of Biomedical Research     Open Access   (Followers: 2)
International Journal of Biotechnology     Hybrid Journal   (Followers: 5)
International Journal of Biotechnology and Molecular Biology Research     Open Access   (Followers: 2)
International Journal of Biotechnology for Wellness Industries     Partially Free   (Followers: 1)
International Journal of Environment, Agriculture and Biotechnology     Open Access   (Followers: 5)
International Journal of Functional Informatics and Personalised Medicine     Hybrid Journal   (Followers: 4)
International Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Radiation Biology     Hybrid Journal   (Followers: 4)
Iranian Journal of Biotechnology     Open Access  
ISABB Journal of Biotechnology and Bioinformatics     Open Access  
Italian Journal of Food Science     Open Access   (Followers: 1)
Journal of Biometrics & Biostatistics     Open Access   (Followers: 3)
Journal of Bioterrorism & Biodefense     Open Access   (Followers: 6)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 1)
Journal of Advanced Therapies and Medical Innovation Sciences     Open Access  
Journal of Advances in Biotechnology     Open Access   (Followers: 5)
Journal Of Agrobiotechnology     Open Access  
Journal of Analytical & Bioanalytical Techniques     Open Access   (Followers: 7)
Journal of Animal Science and Biotechnology     Open Access   (Followers: 4)
Journal of Applied Biomedicine     Open Access   (Followers: 2)
Journal of Applied Biotechnology     Open Access   (Followers: 2)
Journal of Applied Biotechnology Reports     Open Access   (Followers: 2)
Journal of Applied Mathematics & Bioinformatics     Open Access   (Followers: 5)
Journal of Biologically Active Products from Nature     Hybrid Journal   (Followers: 1)
Journal of Biomaterials and Nanobiotechnology     Open Access   (Followers: 6)
Journal of Biomedical Photonics & Engineering     Open Access  
Journal of Biomedical Practitioners     Open Access  
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription  
Journal of Bioprocessing & Biotechniques     Open Access  
Journal of Biosecurity, Biosafety and Biodefense Law     Hybrid Journal   (Followers: 3)
Journal of Biotechnology     Hybrid Journal   (Followers: 68)
Journal of Biotechnology and Strategic Health Research     Open Access  
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 9)
Journal of Chitin and Chitosan Science     Full-text available via subscription  
Journal of Colloid Science and Biotechnology     Full-text available via subscription  
Journal of Commercial Biotechnology     Full-text available via subscription   (Followers: 6)
Journal of Crop Science and Biotechnology     Hybrid Journal   (Followers: 3)
Journal of Essential Oil Research     Hybrid Journal   (Followers: 2)
Journal of Experimental Biology     Full-text available via subscription   (Followers: 24)
Journal of Genetic Engineering and Biotechnology     Open Access   (Followers: 5)
Journal of Ginseng Research     Open Access  
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 16)
Journal of Integrative Bioinformatics     Open Access  
Journal of International Biotechnology Law     Hybrid Journal   (Followers: 3)
Journal of Medical Imaging and Health Informatics     Full-text available via subscription  
Journal of Molecular Biology and Biotechnology     Open Access  
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 11)
Journal of Nano Education     Full-text available via subscription  
Journal of Nanobiotechnology     Open Access   (Followers: 4)
Journal of Nanofluids     Full-text available via subscription   (Followers: 1)
Journal of Organic and Biomolecular Simulations     Open Access  
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 4)
Journal of Science and Applications : Biomedicine     Open Access  
Journal of the Mechanical Behavior of Biomedical Materials     Hybrid Journal   (Followers: 11)
Journal of Trace Elements in Medicine and Biology     Hybrid Journal   (Followers: 1)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Journal of Yeast and Fungal Research     Open Access   (Followers: 1)
Marine Biotechnology     Hybrid Journal   (Followers: 4)
Messenger     Full-text available via subscription  
Metabolic Engineering Communications     Open Access   (Followers: 4)
Metalloproteinases In Medicine     Open Access  
Microalgae Biotechnology     Open Access   (Followers: 2)
Microbial Biotechnology     Open Access   (Followers: 9)
MicroMedicine     Open Access   (Followers: 3)
Molecular and Cellular Biomedical Sciences     Open Access  
Molecular Biotechnology     Hybrid Journal   (Followers: 13)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 3)
Nanobiomedicine     Open Access  
Nanobiotechnology     Hybrid Journal   (Followers: 2)
Nanomaterials and Nanotechnology     Open Access  
Nanomaterials and Tissue Regeneration     Open Access  
Nanomedicine and Nanobiology     Full-text available via subscription  
Nanomedicine Research Journal     Open Access  
Nanotechnology Reviews     Hybrid Journal   (Followers: 5)
Nature Biotechnology     Full-text available via subscription   (Followers: 535)

        1 2 | Last

Journal Cover Electronic Journal of Biotechnology
  [SJR: 0.365]   [H-I: 36]   [0 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Print) 0717-3458
   Published by Elsevier Homepage  [3162 journals]
  • Kinetic modeling of the simultaneous production of ethanol and fructose by
           Saccharomyces cerevisiae

    • Authors: Ashraf K. Sulieman; Meilana Dharma Putra; Ahmed E. Abasaeed; Mohamed H. Gaily; Saeed M. Al-Zahrani; Mohamed A. Zeinelabdeen
      Pages: 1 - 8
      Abstract: Publication date: July 2018
      Source:Electronic Journal of Biotechnology, Volume 34
      Author(s): Ashraf K. Sulieman, Meilana Dharma Putra, Ahmed E. Abasaeed, Mohamed H. Gaily, Saeed M. Al-Zahrani, Mohamed A. Zeinelabdeen
      Background Ethanol and fructose are two important industrial products that enjoy many uses. In this contribution, their production via selective fermentation of date extract using Saccharomyces cerevisiae was studied. Scaling up the process for possible commercialization was investigated in three fermentors with working volume ratio of 1:40:400. Results Higher ethanol concentration was obtained in the larger fermentor due to conversion of fructose. Fructose yields in the 0.5-L, 7.5-L and 80-L fermentors were 99, 92 and 90%, respectively. Good fitting was obtained with the modified Monod kinetics; however, a better fit of cell mass was obtained with the modified Ghose–Tyagi model which accounts for ethanol inhibition. Conclusions The modified Gompertz model was expanded to facilitate prediction of products' formation and fructose fractions in all three fermentors. Such expansion will be beneficial in industrial applications. How to cite: Sulieman AK, Putra MD, Abasaeed AE, et al. Kinetic modeling of the simultaneous production of ethanol and fructose by Saccharomyces cerevisiae. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.04.006.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.04.006
      Issue No: Vol. 34 (2018)
       
  • Comparison of the phenolic contents and epigenetic and genetic variability
           of wild and cultivated watercress (Rorippa nasturtium var. aquaticum L.)

    • Authors: Marcela Verónica Gutiérrez-Velázquez; Norma Almaraz-Abarca; Yolanda Herrera-Arrieta; José Antonio Ávila-Reyes; Laura Silvia González-Valdez; Rene Torres-Ricario; José Natividad Uribe-Soto; Hugo Manuel Monreal-García
      Pages: 9 - 16
      Abstract: Publication date: July 2018
      Source:Electronic Journal of Biotechnology, Volume 34
      Author(s): Marcela Verónica Gutiérrez-Velázquez, Norma Almaraz-Abarca, Yolanda Herrera-Arrieta, José Antonio Ávila-Reyes, Laura Silvia González-Valdez, Rene Torres-Ricario, José Natividad Uribe-Soto, Hugo Manuel Monreal-García
      Background Epigenetic modifications are key factors modulating the expression of genes involved in the synthesis of phytochemicals. The knowledge of plant epigenetic and genetic variations can contribute to enhance the production of bioactive compounds. These issues have been little explored thus far in Rorippa nasturtium var. aquaticum L. (watercress), an edible and medicinal plant. The aim of the current study was to determine and compare the phenolic composition and epigenetic and genetic variations between wild and cultivated watercress. Results Significant differences were found in the quantitative phenolic composition between wild and cultivated watercress. The eight primer combinations used in the methylation-sensitive amplification polymorphism (MSAP) method revealed different epigenetic status for each watercress type, the cultivated one being the most epigenetically variable. The genetic variability revealed by the EcoRI/MspI amplification profile and also by eight inter-simple sequence repeat (ISSR) primers was different between the two types of watercress. The results of the Mantel test showed that the correlation between genetic and epigenetic variations has diminished in the cultivated type. Cluster analyses showed that the epigenetic and genetic characterizations clearly discriminated between wild and cultivated watercress. Conclusions Relevant chemical, epigenetic, and genetic differences have emerged between wild and cultivated watercress. These differences can contribute to fingerprint and develop quality control tools for the integral and safety use and the commercialization of watercress. The richness of epialleles could support the development of tools to manipulate the watercress epigenome to develop high bioproduct–producing cultivars. How to cite: Gutiérrez-Velázquez MV, Almaraz-Abarca N, Herrera-Arrieta Y, et al. Comparison of the phenolic contents and the epigenetic and genetic variability of wild and cultivated watercress (Rorippa nasturtium var. aquaticum L.). Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.04.005.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.04.005
      Issue No: Vol. 34 (2018)
       
  • The genetic diversity of wild and cultivated Manila clam (Ruditapes
           philippinarum) revealed by 29 novel microsatellite markers

    • Authors: Liwen Jiang; Hongtao Nie; Chen Li; Dongdong Li; Zhongming Huo; Xiwu Yan
      Pages: 17 - 21
      Abstract: Publication date: July 2018
      Source:Electronic Journal of Biotechnology, Volume 34
      Author(s): Liwen Jiang, Hongtao Nie, Chen Li, Dongdong Li, Zhongming Huo, Xiwu Yan
      Background Microsatellite loci often used as a genetic tool for estimating genetic diversity population variation in a wide variety of different species. The application of microsatellite markers in genetics and breeding includes investigating the genetic differentiation of wild and cultured populations, assessing and determining the genetic relationship of different populations. The aim of this work is to develop several microsatellite markers via high-throughput sequencing and characterize these markers in commercially important bivalve Ruditapes philippinarum. Results Among the two populations of R. philippinarum studied, 110 alleles were detected. The number of alleles at the cultured population ranged from 3 to 17 (mean NA = 6.897) and wild population ranged from 2 to 15 (mean NA = 6.793). The observed and expected heterozygosities of cultured population ranged from 0.182 to 0.964, and from 0.286 to 0.900, with an average of 0.647 and 0.692, respectively. The observed and expected heterozygosities of wild population ranged from 0.138 to 1.000, and from 0.439 to 0.906, with an average of 0.674 and 0.693, respectively. The polymorphism information content ranged from 0.341 to 0.910 with an average of 0.687. Sixteen and thirteen microsatellite loci deviated significantly from Hardy–Weinberg equilibrium after correction for multiple tests in cultured and wild population, respectively. Conclusions Twenty-nine novel microsatellite loci were developed using Illumina paired-end shotgun sequencing and characterized in two population of R. philippinarum. How to cite: Jiang L, Nie H, Li C, et al. The genetic diversity of wild and cultivated Manila clam (Ruditapes philippinarum) revealed by 29 novel microsatellite markers. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.003.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.003
      Issue No: Vol. 34 (2018)
       
  • Melanoma transplants in “green” mice: Fluorescent cells in tumors are
           not equivalent to host-derived cells

    • Authors: Dolores C. García-Olmo; María G. Picazo; Damián García-Olmo
      Pages: 22 - 28
      Abstract: Publication date: July 2018
      Source:Electronic Journal of Biotechnology, Volume 34
      Author(s): Dolores C. García-Olmo, María G. Picazo, Damián García-Olmo
      Background To examine the usefulness of green fluorescent protein (GFP) mice for studying the interactions between normal cells and tumor cells in a host, we used a melanoma model in such “green” mice [C57BL/6-Tg(CAG-EGFP)1Osb mice]. Mice were given a subcutaneous injection of B16-F10 cells, and the resultant primary tumors were removed. Then cells from individual tumors were cultured. Results The proportion of EFGP+ cells was determined by fluorescence-activated cell sorting (FACS) and was 6.8% ± 3.2% (mean ± s.d.) on day 1 of culture, 0.6% ± 0.3% on day 2, and 0.02% ± 0.01% at day 7. In all cases, isolated cells grew at a constant rate, but fluorescence decreased over time and became undetectable on day 14. Cells were tested using PCR for the presence of an EGFP-specific sequence, and results were negative in all cases, thus indicating that the cells did not harbor the host's reporter gene. Cells were also tested for the presence of EGFP mRNA, which was consistently detected for 22 days after the start of culture. The tumorogenicity of the cultured cells was confirmed in GFP mice injected with cells from a selection of cultures. Conclusions In a melanoma model in GFP mice, the detection of “green” cells in tumors was not equivalent to the detection of host-derived cells. Such “masking” was caused by a transient, but lasting, transfer of EGFP mRNA from the host's normal cells to tumor cells. Thus, an analysis of tumors postmortem by techniques that yield only a single snapshot can lead to incorrect interpretations and erroneous conclusions.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.04.007
      Issue No: Vol. 34 (2018)
       
  • Pretentious genomic selection signatures in CYP19A1 gene associated with
           silent estrous behavior in water buffalo in Pakistan

    • Authors: Sana Imran; Javed Maryam; Asif Nadeem; Madiha Iqbal
      Pages: 35 - 40
      Abstract: Publication date: March 2018
      Source:Electronic Journal of Biotechnology, Volume 32
      Author(s): Sana Imran, Javed Maryam, Asif Nadeem, Madiha Iqbal
      Background Poor reproductive efficiency of river buffalos hampers the production capabilities of animals. Buffalos are mainly considered poor breeders owing to the constrained expression of estrus behavior. Failure to display heat signs is an indication of improper functionality of signaling peptides to trigger on a series of behavioral changes, which can be detectable by breeders for timely insemination of females. This might cause an animal to be a repeat breeder. Genomic variations underlying synthesis of signaling peptides can be a useful marker to select superior animals with better reproductive efficiency. In this context, the current study was designed to analyze the CYP19A1 gene in Nili-Ravi buffalo. Results A total of 97 animals were selected and were divided into two groups on the basis of their heat score. PCR amplification and sequencing of the amplicons were performed using the specific sets of primer, and then, sequences were analyzed for novel variants. A total of 11 polymorphic sites were identified illustrating phenotypic variation in the heat score. Most of the loci were found homologous. Single Nucleotide Polymorphisms (SNPs) were analyzed for association with silent estrus. A three-dimensional protein model was also generated to locate the position of exonic SNPs. Conclusion This study illustrated that polymorphic sites in the CYP19A1 gene provided potential markers for selection of buffalos with better estrus behavior.

      PubDate: 2018-02-17T05:33:24Z
      DOI: 10.1016/j.ejbt.2018.01.001
      Issue No: Vol. 32 (2018)
       
  • Genomic comparisons of Rhizobium species using in silico AFLP-PCR,
           endonuclease restrictions and ampylating enzymes

    • Authors: M. Amjad Qureshi; Muhammad Tariq Pervez; Masroor Ellahi Babar; Tanveer Hussain; Muhammad Shoaib; Syed Shah Mohammad
      Abstract: Publication date: Available online 26 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): M. Amjad Qureshi, Muhammad Tariq Pervez, Masroor Ellahi Babar, Tanveer Hussain, Muhammad Shoaib, Syed Shah Mohammad
      Background The whole genome sequences of nine Rhizobium species were evaluated using different in-silico molecular techniques such as AFLP-PCR, restriction digest and AMPylating enzymes. The entire genome sequences were aligned with ProgressiveMauve and visualized through phylogenetic tree reconstructed using NTSYS pc 2.11X. The “insilico.ehu.es” was used to carry out in-silico AFLP-PCR and in-silico restriction digest of the selected genomes. Post-translational modification (PTM) and AMPylating enzymes diversity between the proteome of Rhizobium species were determined by novPTMenzy. Results Slight variations were observed in the phylogeny based on AFLP-PCR and PFGE and the tree based on whole genome. Results clearly demonstrated the presence of PTM's i.e. AMPylation with the GS-ATasE (GlnE), Hydroxylation and Sulfation with their domain and Deamidation with their specific domains (ampylating enzymes) GS-ATasE (GlnE), Fic, Doc (Phosphorylation); Asparagine_hydroxylase, Collagen_prolyl_lysyl_hydroxylase; Sulfotransferase and CNF (Cytotoxic Necrotizing Factors), respectively. The results pertaining to post translational modifications are discussed with relation to functional diversities reported in these species. Conclusions The phylogenetic tree based on AFLP-PCR was slightly different from restriction endonucleases and PFGE based tree. Different post translational modifications (PTM's) were observed in the Rhizobium species and the most prevailing type of PTM was AMPylation with the GS-ATasE (GlnE). Another type of PTM's was also observed i.e. Hydroxylation followed by Sulfation with domains i.e. Asparagine_hydroxylase, Collagen_prolyl_lysyl_hydroxylase and Sulfotransferase. The deamidation type of PTM was present only in Rhizobium sp. NGR234.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.006
       
  • JcZFP8, a C2H2 zinc-finger protein gene from Jatropha curcas, influences
           plant development in transgenic tobacco

    • Authors: Xiaodong Shi; Yan Wu; Tingwei Dai; Yuxi Gu; Linghui Wang; Xiaobo Qin; Ying Xu; Fang Chen
      Abstract: Publication date: Available online 26 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Xiaodong Shi, Yan Wu, Tingwei Dai, Yuxi Gu, Linghui Wang, Xiaobo Qin, Ying Xu, Fang Chen
      Background Jatropha curcas L., as an important strategic biofuel resource with considerable economic potential, has attracted worldwide attention. However, J. curcas has yet to be domesticated. Plant height, an important agronomic trait of J. curcas, has not been sufficiently improved and the genetic regulation of this trait in J. curcas is not fully understood. Zinc-finger proteins (ZFPs), a class of transcription factors, have previously been shown to play critical roles in regulating multiple aspects of plant growth and development, and may accordingly be implicated in the genetic regulation of plant height in J. curcas. Results In this study, we cloned JcZFP8, a C2H2 ZFP gene in J. curcas. We found that the JcZFP8 protein was nuclear localized and contained a conserved QALGGH motif in its C2H2 structure. Furthermore, ectopic expression of JcZFP8 under control of the 35S promoter in transgenic tobacco resulted in dwarf plants with malformed leaves. However, when JcZFP8 was knocked out, the transgenic tobacco did not show the dwarf phenotype. After treatment with the gibberellic acid biosynthesis inhibitor paclobutrazol (PAC), the dwarf phenotype was more severe compared with plants that did not receive the PAC treatment, whereas application of exogenous gibberellin3 (GA3) reduced the dwarf phenotype in transgenic plants. Conclusions The results of this study indicate that JcZFP8 plays a role in J. curcas plant form via GA-related pathways. Our findings may help us to understand the genetic regulation of plant development in J. curcas, and accelerate breeding progress through engineering of the GA metabolic pathway in this plant.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.008
       
  • Poly(3-hydroxybutyrate) graft copolymer dense membranes for human
           mesenchymal stem cell growth

    • Authors: Maykel González-Torres; Roberto Sánchez-Sánchez; Silvia G. Solís-Rosales; Witold Brostow; Eric Reyes-Cervantes; Janet Alejandra Gutiérrez-Uribe; Phaedra Silva-Bermúdez; María de los Angeles Moyaho-Bernal; María Cristina Velasquillo-Martínez
      Abstract: Publication date: Available online 25 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Maykel González-Torres, Roberto Sánchez-Sánchez, Silvia G. Solís-Rosales, Witold Brostow, Eric Reyes-Cervantes, Janet Alejandra Gutiérrez-Uribe, Phaedra Silva-Bermúdez, María de los Angeles Moyaho-Bernal, María Cristina Velasquillo-Martínez
      Background The use of novel materials as an artificial extracellular matrix for stem cell growth is a current strategy of increasing interest for regenerative medicine. Here, we prepare thermal-remolded membrane scaffolds from poly(3-hydroxybutyrate) grafted with 2-amino-ethyl methacrylate hydrochloride. However, it is unclear whether these membranes are useful for tissue engineering. Results The mechanical properties, tribology, and morphology of the dense membranes were assessed. The results show that tensile strain at break and roughness of the compressed membrane decrease with increasing graft degree. Moreover, graft copolymer membranes showed lower resistance to scratching, greater degree of swelling and higher brittleness than un-grafted P(3HB) films. Thus, it effectively supports the growth of dermal fibroblast, as demonstrated by epifluorescence microscopy. Conclusions It is concluded that the developed membrane can be properly used in is the restoration of skin tissue.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.007
       
  • Development of a direct transformation method by GFP screening and in
           vitro whole plant regeneration of Capsicum frutescens L.

    • Authors: Marcus Jenn Yang Chee; Grantley W. Lycett; Chiew Foan Chin
      Abstract: Publication date: Available online 18 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Marcus Jenn Yang Chee, Grantley W. Lycett, Chiew Foan Chin
      Background Capsicum is a genus of an important spice crop that belongs to the chili lineage. However, many Capsicum species (family Solanaceae) are known to be recalcitrant to genetic transformation and in vitro regeneration, thus hampering the effort in using Capsicum species for detailed biological investigation. In this study, we have developed an optimized protocol for the direct transformation of Capsicum frutescens L. cv. Hot Lava using a biolistic particle delivery system. In addition, a procedure for in vitro whole plant regeneration from the hypocotyl explants of C. frutescens was established. Results In this study on the biolistic system, explant target distance, bombardment helium (He) pressure, and the size of the microcarrier were the key parameters to be investigated. The optimized parameters based on the screening of GFP expression were determined to have a target distance of 6 cm, helium pressure of 1350 psi, and gold particle (microcarrier) size of 1.6 μm. The greatest number of shoots was obtained from hypocotyls as explants using Murashige and Skoog medium supplemented with 5.0-mg/L 6-benzylaminopurine and 0.1-mg/L 1-naphthaleneacetic acid. On an average, five shoots per explant were formed, and of them, one shoot managed to form the root and developed into a whole plant. Conclusions We obtained an optimized protocol for the biolistic transformation of chili and in vitro regeneration of chili plantlets. The establishment of the protocols will provide a platform for molecular breeding and biological studies of chili plants.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.005
       
  • Effects of all-trans retinoic acid on goat dermal papilla cells cultured
           in vitro

    • Authors: Sen Ma; Guangxian Zhou; Yulin Chen
      Abstract: Publication date: Available online 15 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Sen Ma, Guangxian Zhou, Yulin Chen
      Background All-trans retinoic acid (ATRA), a vitamin A-derived active metabolite, exerts important functions in hair biology. Previous studies indicated that excess ATRA hampered hair follicle morphogenesis and cyclic regeneration in adulthood, but other studies stated that ATRA promoted hair growth. Dermal papilla (DP), a cluster of specialized fibroblasts, plays pivotal roles in controlling development and regeneration of hair follicle. Several lines of evidence indicated that DP might be the target cells of ATRA in the hair follicle. To confirm this hypothesis, the present study was performed to explore the biological effects of ATRA on goat dermal papilla cells (DPCs) and clarify the roles of ATRA in hair biology. Results Our experimental results indicated that key signaling transducers of ATRA were dynamically expressed in distinct stages of goat cashmere growth cycle, and high-dose ATRA treatment (10-5 M) significantly impaired the viability of goat DPCs and lowered the ratio of proliferating cells. Otherwise, goat DPCs were stimulated to enter apoptosis and their cell cycle progression was severely blocked by ATRA. Moreover, the expression of fibroblast growth factor 7 (Fgf7), one of the potent hair growth stimulators secreted by DPCs, was transcriptionally repressed following ATRA treatment. Conclusion DPCs are the targets of ATRA in the hair follicle, and ATRA negatively regulates hair growth by the targeted suppression of cell viability and growth factor expression of goat DPCs. Through these observations, we offer a new mechanistic insight into the roles of ATRA in hair biology.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.004
       
  • Heterologous expression and enhanced production of β-1,4-glucanase of
           Bacillus halodurans C-125 in Escherichia coli

    • Authors: Nadia Zeeshan; Saher Naz; Shumaila Naz; Amber Afroz; Muzna Zahur; Safia Zia
      Abstract: Publication date: Available online 11 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Nadia Zeeshan, Saher Naz, Shumaila Naz, Amber Afroz, Muzna Zahur, Safia Zia
      Background Recombinant DNA technology enables us to produce proteins with desired properties and insubstantial amount for industrial applications. Endo-1, 4-β-glucanases (Egl) is one of the major enzyme involved in degradation of cellulose, an important component of plant cell wall. The present study was aimed at enhancing the production of endo-1, 4-β-glucanases (Egl) of Bacillus halodurans in Escherichia coli. Results A putative Egl gene of Bacillus Halodurans was expressed in E. coli by cloning in pET 22b (+). On induction with isopropyl-b-D-1-thiogalactopyranoside, the enzyme expression reached upto ~20% of the cell protein producing 29.2mg/l culture. An increase in cell density to 12 in auto-inducing LB medium (absorbance at 600nm enhanced β--glucanase production upto 5.4 fold. The molecular mass of the enzyme was determined to be 39 KDa, which is nearly the same as the calculated value. Protein sequence was analyzed by CDD, Pfam, I TASSER, COACH, PROCHECK Servers and putative amino acids involved in the formation of catalytic, substrate and metal binding domains were identified. Phylogenetic analysis of the β-glucanases of B. halodurans was performed and position of Egl among other members of the genus Bacillus producing endo-glucanases was determined. Temperature and pH optima of the enzyme were found to be 60°C and 8.0, respectively, under the assay conditions. Conclusion Production of endo-1, 4 β-glucanase enzymes from B. halodurans increased several folds when cloned in pET vector and expressed in E. coli. To our knowledge, this is the first report of high-level expression and characterization of an endo-1, 4 β-glucanases from B. halodurans.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.001
       
  • Hydrolytic efficiency and isomerization during de-esterification of
           natural astaxanthin esters by saponification and enzymolysis

    • Authors: Fang Su; Huarong Xu; Na Yang; Wei Liu; Jianguo Liu
      Abstract: Publication date: Available online 10 May 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Fang Su, Huarong Xu, Na Yang, Wei Liu, Jianguo Liu
      Background Astaxanthin from natural sources is typically esterified with fatty acids; hence, it must be hydrolyzed to remove esters before identification and quantification by conventional HPLC. Alkaline-catalyzed saponification and enzyme-catalyzed enzymolysis are the most commonly used de-esterification methods. However, information on the efficiency and isomerization during de-esterification of natural astaxanthin esters by these two methods remains scarce. Therefore, we conducted two HPLC-based experiments to determine which method is better for hydrolyzing astaxanthin esters. Results To assess the effect of enzymolysis (0.67 U/mL cholesterol esterase, at 37°C) and saponification (0.021 M NaOH, at 5°C) conditions on free astaxanthin recovery and destruction or structural transformation of astaxanthin, we varied the total treatment time across a range of 195 min. The results showed that enzymolysis and saponification were complete in 60 min and 90 min, respectively. After complete hydrolysis, the maximum free astaxanthin recovery obtained by enzymolysis was 42.6% more than that obtained by saponification. The identification of by-products, semi-astacene and astacene, during the process of saponification also indicated that a more severe degradation of astaxanthin occurred during saponification. Moreover, the composition of astaxanthin isomers during saponification was similar to that of the isomers during enzymolysis between 30 min and 75 min (all-trans:9-cis:13-cis = 21:3:1, approximately) but dramatically changed after 90 min, whereas the composition in the enzymolysis treatment remained relatively stable throughout. Conclusion Compared with saponification, enzymolysis with cholesterol esterase was recommended as a more accurate method for de-esterification of natural astaxanthin esters for further qualitative and quantitative HPLC analysis.

      PubDate: 2018-05-31T23:48:22Z
      DOI: 10.1016/j.ejbt.2018.05.002
       
  • Biofiltration of trimethylamine in biotrickling filter inoculated with
           Aminobacter aminovorans

    • Authors: Alberto Aguirre; Pamela Bernal; Daniela Maureira; Nicolás Ramos; Javier Vásquez; Homero Urrutia; Juan Carlos Gentina; Germán Aroca
      Abstract: Publication date: Available online 17 April 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Alberto Aguirre, Pamela Bernal, Daniela Maureira, Nicolás Ramos, Javier Vásquez, Homero Urrutia, Juan Carlos Gentina, Germán Aroca
      Background Trimethylamine (TMA) is the main responsible for the odor associated with rotting fish and other annoying odors generated in many industrial activities. Biofiltration has proved to be efficient for treating odorous gaseous emissions. The main objective of this work was to determine the removal capacity of TMA of a biotrickling filter inoculated with Aminobacter aminovorans and to evaluate the effect of H2S on its performance. Results The maximum specific growth rate of A. aminovorans in a liquid culture was 0.15h−1, with a TMA to biomass yield of 0.10 (gg−1) and a specific consumption rate of 0.062g·g−1·h−1. The initial specific consumption rate of TMA was highly influenced by the presence of H2S in liquid culture at concentrations of 20 and 69ppm in heading space of the flasks. A BTF inoculated with A. aminovorans showed removal efficiencies higher than 98% in a range of loading rate of 0.2 to 8g·m−3·h−1 at empty bed residence time (EBRT) of 85 and 180s. No effect on the elimination capacity and efficiency was detected when H2S was added at 20 and 50ppm to the inlet gaseous emission, though the fraction of A. aminovorans measured by qPCR in the biofilm decreased. Conclusions A biotrickling filter inoculated with A. aminovorans can remove efficiently the TMA in a gaseous stream. The elimination capacity of TMA can be negatively affected by H2S, but its effect is not notorious when it is forming part of a biofilm, due to its high specific consumption rate of TMA.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.04.004
       
  • Draft genomes and reference transcriptomes extend the coding potential of
           the fish pathogen Piscirickettsia salmonis

    • Authors: Angela D. Millar; Paz Tapia; Fernando A. Gómez; Sergio H. Marshall; Derie E. Fuentes; Jorge H. Valdes
      Abstract: Publication date: Available online 12 April 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Angela D. Millar, Paz Tapia, Fernando A. Gómez, Sergio H. Marshall, Derie E. Fuentes, Jorge H. Valdes
      Background Draft and complete genome sequences from bacteria are key tools to understand genetic determinants involved in pathogenesis in several disease models. Piscirickettsia salmonis is a Gram-negative bacterium responsible for the Salmon Rickettsial Syndrome (SRS), a bacterial disease that threatens the sustainability of the Chilean salmon industry. In previous reports, complete and draft genome sequences have been generated and annotated. However, the lack of transcriptome data underestimates the genetic potential, does not provide information about transcriptional units and contributes to disseminate annotation errors. Results Here we present the draft genome and transcriptome sequences of four P. salmonis strains. We have identified the transcriptional architecture of previously characterized virulence factors and trait-specific genes associated to cation uptake, metal efflux, antibiotic resistance, secretion systems and other virulence factors. Conclusions This data has provided a refined genome annotation and also new insights on the transcriptional structures and coding potential of this fish pathogen.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.04.002
       
  • Agroindustrial biomass for xylanase production by Penicillium chrysogenum:
           Purification, biochemical properties and hydrolysis of hemicelluloses

    • Authors: Cárol Cabral Terrone; Caroline de Freitas; César Rafael Fanchini Terrasan; Alex Fernando de Almeida; Eleonora Cano Carmona
      Abstract: Publication date: Available online 12 April 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Cárol Cabral Terrone, Caroline de Freitas, César Rafael Fanchini Terrasan, Alex Fernando de Almeida, Eleonora Cano Carmona
      Background In this work, the xylanase production by Penicillium chrysogenum F-15 strain was investigated using agroindustrial biomass as substrate. The xylanase was purified, characterized and applied in hemicellulose hydrolysis. Results The highest xylanase production was obtained when cultivation was carried out with sugar cane bagasse as carbon source, at pH6.0 and 20°C, under static condition for 8d. The enzyme was purified by a sequence of ion exchange and size exclusion chromatography, presenting final specific activity of 834.2U·mg·prot-1. The molecular mass of the purified enzyme estimated by SDS-PAGE was 22.1kDa. The optimum activity was at pH6.5 and 45°C. The enzyme was stable at 40°C with half-life of 35min, and in the pH range from 4.5 to 10.0. The activity was increased in the presence of Mg+2 and Mn+2 and reducing agents such as DTT and β-mercaptoethanol, but it was reduced by Cu+2 and Pb+2. The xylanase presented Km of 2.3mM and Vmax of 731.8U·mg·prot-1 with birchwood xylan as substrate. This xylanase presented differences in its properties when it was compared to the xylanases from other P. chrysogenum strains. Conclusion The xylanase from P. chrysogenum F-15 showed lower enzymatic activity on commercial xylan than on hemicellulose from agroindustry biomass and its biochemistry characteristics, such as stability at 40°C and pH from 4.0 to 10.0, shows the potential of this enzyme for application in food, feed, pulp and paper industries and for bioethanol production.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.04.001
       
  • Removing the by-products acetic acid and NH4+ from the l-tryptophan broth
           by vacuum thin film evaporation during l-tryptophan production

    • Authors: Qingyang Xu; Fang Bai; Ning Chen; Gang Bai
      Abstract: Publication date: Available online 11 April 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Qingyang Xu, Fang Bai, Ning Chen, Gang Bai
      Background During l-tryptophan production by Escherichia coli, the by-products, acetic acid and NH4 +, accumulate in the fermentation broth, resulting in inhibited cell growth and activity and decreased l-tryptophan production. To improve the l-tryptophan yield and glucose conversion rate, acetic acid and NH4 + were removed under low-temperature vacuum conditions by vacuum scraper concentrator evaporation; the fermentation broth after evaporation was pressed into another fermenter to continue fermentation. To increase the volatilisation rate of acetic acid and NH4 + and reduce damage to bacteria during evaporation, different vacuum evaporation conditions were studied. Results The optimum operating conditions were as follows: vacuum degree, 720mmHg; concentration ratio, 10%; temperature, 60°C; and feeding rate, 300mL/min. The biomass yield of the control fermentation (CF) and fermentation by vacuum evaporation (VEF) broths was 55.1g/L and 58.3g/L at 38h, respectively, (an increase of 5.8%); the living biomass yield increased from 8.9 (CF) to 10.2pF (VEF; an increase of 14.6%). l-tryptophan production increased from 50.2g/L (CF) to 60.2g/L (VEF) (an increase of 19.9%), and glucose conversion increased from 18.2% (CF) to 19.5% (VEF; an increase of 7.1%). The acetic acid concentrations were 2.74g/L and 6.70g/L, and the NH4 + concentrations were 85.3mmol/L and 130.9mmol/L in VEF and CF broths, respectively. Conclusions The acetic acid and NH4 + in the fermentation broth were quickly removed using the vacuum scraper concentrator, which reduced bacterial inhibition, enhanced bacterial activity, and improved the production of l-tryptophan and glucose conversion rate.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.04.003
       
  • Evaluation of biogas and syngas as energy vectors for heat and power
           generation using lignocellulosic biomass as raw material

    • Authors: Juan Camilo Solarte-Toro; Yessica Chacón-Pérez; Carlos Ariel Cardona-Alzate
      Abstract: Publication date: Available online 3 April 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Juan Camilo Solarte-Toro, Yessica Chacón-Pérez, Carlos Ariel Cardona-Alzate
      The use of nonrenewable energy sources to provide the worldwide energy needs has caused different problems such as global warming, water pollution, and smog production. In this sense, lignocellulosic biomass has been postulated as a renewable energy source able to produce energy carriers that can cover this energy demand. Biogas and syngas are two energy vectors that have been suggested to generate heat and power through their use in cogeneration systems. Therefore, the aim of this review is to develop a comparison between these energy vectors considering their main features based on literature reports. In addition, a techno-economic and energy assessment of the heat and power generation using these vectors as energy sources is performed. If lignocellulosic biomass is used as raw material, biogas is more commonly used for cogeneration purposes than syngas. However, syngas from biomass gasification has a great potential to be employed as a chemical platform in the production of value-added products. Moreover, the investment costs to generate heat and power from lignocellulosic materials using the anaerobic digestion technology are higher than those using the gasification technology. As a conclusion, it was evidenced that upgraded biogas has a higher potential to produce heat and power than syngas. Nevertheless, the implementation of both energy vectors into the energy market is important to cover the increasing worldwide energy demand.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.03.005
       
  • Scaling-up fermentation of Escherichia coli for production of recombinant
           P64k protein from Neisseria meningitidis

    • Authors: Raúl Espinosa Pérez; José García Suárez; Emilio Narciandi Diaz; Ricardo Silva Rodríguez; Evelin Caballero Menéndez; Héctor Díaz Balaguer; Alexis Musacchio Lasa
      Abstract: Publication date: Available online 29 March 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Raúl Espinosa Pérez, José García Suárez, Emilio Narciandi Diaz, Ricardo Silva Rodríguez, Evelin Caballero Menéndez, Héctor Díaz Balaguer, Alexis Musacchio Lasa
      Background P64k is a Neisseria meningitidis high molecular weight protein present in meningococcal vaccine preparations. The lpdA gene, which encodes for this protein, was cloned in Escherichia coli and the P64k recombinant protein was expressed in E. coli K12 GC366 cells under the control of a tryptophan promoter. P64k was expressed as an intracellular soluble protein about 28% of the total cellular protein. Several scale-up criteria of fermentation processes were studied to obtain the recombinant P64k protein at the pilot production scale. Results The best operational conditions at a larger scale production of P64k recombinant protein were studied and compared using the four following criteria: Constant Reynold's number (Re constant), Constant impeller tip speed (n di constant), Constant power consumption per unit liquid volume (P/V constant) and Constant volumetric oxygen transfer coefficients (KLa/k constant). The highest production of the recombinant protein was achieved based on the constant KLa/k scale-up fermentation criterion, calculating the aeration rate (Q) and the impeller agitation speed (n) by iterative process, keeping constant the KLa/k value from bench scale. The P64k protein total production at the 50l culture scale was 546mgl-1 in comparison with the 284mgl-1 obtained at 1.5l bench scale. Conclusions The methodology described herein, for the KLa/k scale-up fermentation criterion, allowed us to obtain the P64k protein at 50l scale. A fermentation process for the production of P64k protein from N. meningitidis was established, a protein to be used in future vaccine formulations in humans.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.03.004
       
  • Methods for the genetic manipulation of marine bacteria

    • Authors: Zahraa Zeaiter; Francesca Mapelli; Elena Crotti; Sara Borin
      Abstract: Publication date: Available online 26 March 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Zahraa Zeaiter, Francesca Mapelli, Elena Crotti, Sara Borin
      Genetic manipulation of bacteria is a procedure necessary to obtain new strains that express peculiar and defined genetic determinants or to introduce genetic variants responsible for phenotypic modifications. This procedure can be applied to explore the biotechnological potential associated with environmental bacteria and to utilize the functional properties of specific genes when inserted into an appropriate host. In the past years, marine bacteria have received increasing attention because they represent a fascinating reservoir of genetic and functional diversity that can be utilized to fuel the bioeconomy sector. However, there is an urgent need for an in-depth investigation and improvement of the genetic manipulation tools applicable to marine strains because of the paucity of knowledge regarding this. This review aims to describe the genetic manipulation methods hitherto used in marine bacteria, thus highlighting the limiting factors of the different techniques available today to increase manipulation efficiency. In particular, we focus on methods of natural and artificial transformations (especially electroporation) and conjugation because they have been successfully applied to several marine strains. Finally, we emphasize that, to avoid failure, future work should be carried out to establish tailored methodologies for marine bacteria.

      PubDate: 2018-04-18T09:32:06Z
      DOI: 10.1016/j.ejbt.2018.03.003
       
  • Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive
           compound through alteration of EPS and epiphytic bacteria

    • Authors: Claudia Infante; Francisca Castillo; Vilma Pérez; Carlos Riquelme
      Abstract: Publication date: Available online 14 March 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Claudia Infante, Francisca Castillo, Vilma Pérez, Carlos Riquelme
      Background Marine ecosystems contain benthic microalgae and bacterial species that are capable of secreting extracellular polymeric substances (EPS), suggesting that settlement of these microorganisms can occur on submerged surfaces, a key part of the first stage of biofouling. Currently, anti-fouling treatments that help control this phenomenon involve the use of biocides or antifouling paints that contain heavy metals, which over a long period of exposure can spread to the environment. The bacterium Alteromonas sp. Ni1-LEM has an inhibitory effect on the adhesion of Nitzschia ovalis, an abundant diatom found on submerged surfaces. Results We evaluated the effect of the bioactive compound secreted by this bacterium on the EPS of biofilms and associated epiphytic bacteria. Three methods of EPS extraction were evaluated to determine the most appropriate and efficient methodology based on the presence of soluble EPS and the total protein and carbohydrate concentrations. Microalgae were cultured with the bacterial compound to evaluate its effect on EPS secretion and variations in its protein and carbohydrate concentrations. An effect of the bacterial supernatant on EPS was observed by assessing biofilm formation and changes in the concentration of proteins and carbohydrates present in the biofilm. Conclusions These results indicate that a possible mechanism for regulating biofouling could be through alteration of biofilm EPS and alteration of the epiphytic bacterial community associated with the microalga.

      PubDate: 2018-03-19T10:26:12Z
      DOI: 10.1016/j.ejbt.2018.03.002
       
  • Increasing pinosylvin production in Escherichia coli by reducing the
           expression level of the gene fabI-encoded enoyl-acyl carrier protein
           reductase

    • Authors: Caheri Salas-Navarrete; Georgina Hernández-Chávez; Noemí Flores; Luz María Martínez; Alfredo Martinez; Francisco Bolívar; Francisco Barona-Gomez; Guillermo Gosset
      Abstract: Publication date: Available online 8 March 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Caheri Salas-Navarrete, Georgina Hernández-Chávez, Noemí Flores, Luz María Martínez, Alfredo Martinez, Francisco Bolívar, Francisco Barona-Gomez, Guillermo Gosset
      Background The plant secondary metabolite pinosylvin is a polyphenol from the stilbene family, which have positive effects on human health. Biotechnological production is an attractive alternative for obtaining this stilbene. In Escherichia coli, malonyl-CoA is the precursor for both stilbene and fatty acid syntheses. In this study, with the aim of increasing pinosylvin production, we evaluated a novel approach that is based on reducing the expression of the gene fabI, which encodes the enzyme enoyl-acyl carrier protein reductase that is involved in fatty acid synthesis. Results A recombineering method was employed to eliminate the chromosomal -35 promoter sequence and the upstream region of the gene fabI in E. coli strain W3110. Analysis, employing RT-qPCR, showed that such modification caused a 60% reduction in the fabI transcript level in the mutant strain W3110Δ-35fabI::Cm compared to the wild type W3110. Synthetic genes encoding a mutant version of 4-coumaroyl-CoA ligase from Streptomyces coelicolor A3 with improved catalytic activity employing cinnamic acid as substrate and a stilbene synthase from Vitis vinifera were cloned to generate the plasmid pTrc-Sc4CL(M)-VvSTS. The production performance of strains W3110Δ-35fabI::Cm/pTrc-Sc4CL(M)-VvSTS and W3110/pTrc-Sc4CL(M)-VvSTS was determined in shake flask cultures with Luria-Bertani medium supplemented with 10g/L glycerol and 3mM cinnamic acid. Under these conditions, the strain W3110Δ-35fabI::Cm/pTrc-Sc4CL(M)-VvSTS produced 52.67mg/L pinosylvin, a level 1.5-fold higher than that observed with W3110/pTrc-Sc4CL(M)-VvSTS. Conclusion A reduction in the transcript level of fabI caused by the elimination of the -35 and upstream promoter sequences is a successful strategy to improve pinosylvin production in E. coli.

      PubDate: 2018-03-19T10:26:12Z
      DOI: 10.1016/j.ejbt.2018.03.001
       
  • Immunosuppressive mechanism of Hypoderma lineatum secreted serine
           esterase, a potential modulatory method used to inhibit transplant
           rejection

    • Authors: Quangang Chen; Renjin Chen; Honghua Yuan; Peng Liu; Ankang Hu; Lianlian Wu; Jing Liu
      Abstract: Publication date: Available online 3 February 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Quangang Chen, Renjin Chen, Honghua Yuan, Peng Liu, Ankang Hu, Lianlian Wu, Jing Liu
      Background Although immunosuppressive therapies have made organ transplantation a common medical procedure worldwide, chronic toxicity has a major issue for long-term treatment. One method to improve therapies and methods is the application of immunomodulatory agents from parasites such as Hypoderma lineatum. Hypodermin A (HA) is a serine esterase secreted by the larvae of Hypoderma lineatum, several studies demonstrated its immunosuppressive mechanism in vitro, and recently we discovered that HA inhibits the expression of interferon (IFN)-γ and interleukin (IL)-2 and activates IL-10 expression. Therefore, we hypothesized that it might be a potential agent used to block allograft rejections. However, most studies of the immunosuppressive mechanisms associated with HA were undertaken at the cellular level. In order to augment these studies, we evaluated the immunosuppressive effects of HA in vivo using an HA transgenic mouse model. Result Our results revealed similar findings to those reported by in vitro studies, specifically that HA induced prostaglandin E2 expression, downregulated IFN-γ and IL-2 expression, and promoted IL-10 secretion via E-type prostanoid receptor 4. Additionally, we observed that HA overexpression inhibited lipopolysaccharide-induced TLR4 activation. These findings provide insight into a new potential agent capable of blocking graft rejection. Conclusion Our founding suggested that HA-related treatment could be a promising option to improve the viability of grafts in human.

      PubDate: 2018-02-17T05:33:24Z
      DOI: 10.1016/j.ejbt.2018.01.005
       
  • Molecular characterization and expression analysis of cathepsin C in
           Chinese giant salamander (Andrias davidianus) after Aeromonas hydrophila
           infection

    • Authors: Zisheng Wang; Panpan Hang; Qihuan Zhang; Qiaoqing Xu; Zhitao Qi
      Abstract: Publication date: Available online 2 February 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Zisheng Wang, Panpan Hang, Qihuan Zhang, Qiaoqing Xu, Zhitao Qi
      Background Cathepsin C (CTSC) (dipeptidyl peptidase I, DPPI), is a member of the papain superfamily of cysteine proteases and involves in a variety of host reactions. However, the information of CTST in Chinese giant salamander (Andrias davidianus), an amphibian species with important evolutionary position and economic values, remained unclear. Results The full-length salamander CTSC cDNA contained a 96bp of 5′-UTR, a 1392bp of ORF encoding 463 amino acids, and a 95bp of 3′-UTR. The salamander CTSC possessed several sequence features similar to other reported CTSCs such as a signal peptide, a propeptide and a mature peptide. The active site triad of Cys, His and Asn were also found existing in salamander CTSC. Salamander CTSC mRNA was constitutively expressed in all the examined tissues with significantly variant expression level. The highest expression of CTSC was in intestine, followed with stomach, spleen, lung and brain. Following Aeromonas hydrophila infection for 12h, salamander CTSC was significantly up-regulated in several tissues including lung, spleen, brain, kidney, heart, stomach and skin. Conclusion CTSC plays roles in the immune response to bacterial infection, which provided valuable information for further studying the functions of CTSC in salamander.

      PubDate: 2018-02-17T05:33:24Z
      DOI: 10.1016/j.ejbt.2018.01.002
       
  • Intereactions between doripenem and clavulanate — Application of minimal
           inhibitory concentration analysis and cytometry flow for bactericidal
           studies

    • Authors: Katarzyna Ciemniak; Judyta Cielecka-Piontek; Daria Szymanowska; Gabriela Wiergowska
      Abstract: Publication date: Available online 2 February 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Katarzyna Ciemniak, Judyta Cielecka-Piontek, Daria Szymanowska, Gabriela Wiergowska
      Background In view of the current low efficacy of bacterial infection treatment the common trend towards searching for antibiotic systems exhibiting synergistic action is well justified. Among carbapenem analogues a particularly interesting option is provided by combinations of clavulanic acid with meropenem, which have proven to be especially effective. Results Determination of the minimal inhibitory concentration (MIC) along with the method based on flow cytometry constitutes an important tool in the identification of bacterial sensitivity to active substances. Within this study the inhibitory effect of doripenem, clavulanic acid and the doripenem-clavulanate acid system was analyzed in relation to such bacteria as Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Clostridium butyricum and Clostridium pasteurianum, Acinetobacter baumannii, Enterobacter aerogenes. The lowest MIC, amounting to 0.03μg/mL, was observed for the doripenem-clavulanate acid system in the case of E. coli ATCC 25922. In turn, the lowest MIC for doripenem applied alone was recorded for K. pneumoniae ATCC 31488, for which it was 0.1μg/mL. The strain which proved to be most resistant both to doripenem and the doripenem-clavulanate acid system, was A. baumannii, with MIC of 32μg/mL (clinical isolate) and 16μg/mL (reference strain). Cytometric analysis for P. aeruginosa ATCC 27853 and S. aureus ATCC 25923 showed changes in cells following exposure to limiting concentrations of the active substance. Conclusions Analysis of MIC supplies important information concerning microbial sensitivity to active substances, mainly in terms of limiting concentrations causing mortality or vitality of the tested species, which is essential when selecting appropriate antibiotic therapy.

      PubDate: 2018-02-17T05:33:24Z
      DOI: 10.1016/j.ejbt.2018.01.003
       
  • Molecular cloning and biochemical characterization of an α-amylase family
           from Aspergillus niger

    • Authors: Junying Wang; Yu Li; Fuping Lu
      Abstract: Publication date: Available online 31 January 2018
      Source:Electronic Journal of Biotechnology
      Author(s): Junying Wang, Yu Li, Fuping Lu
      Background α-Amylase is widely used in the starch processing, food and paper industries, hydrolyzing starch, glycogen and other polysaccharides into glucose, maltose and oligosaccharides. An α-amylase gene family from Aspergillus niger CBS513.88 encode eight putative α-amylases. The differences and similarities, biochemical properties and functional diversity among these eight α-amylases remains unknown. Results The eight genes were cloned and expressed in Pichia pastoris GS115 by shaking-flask fermentation under the induction of methanol. The sequence alignment, biochemical characterizations and product analysis of starch hydrolysis by these α-amylases were investigated. It is found that the eight α-amylases belonged to three different groups with the typical structure of fungal α-amylase. They exhibited maximal activities at 30–40°C except AmyG and were all stable at acidic pH. Ca2+ and EDTA had no effects on the activities of α-amylases except AmyF and AmyH, indicating that the six amylases were Ca2+ independent. Two novel α-amylases of AmyE and AmyF were found. AmyE hydrolyzed starch into maltose, maltotriose and a small amount of glucose, while AmyF hydrolyzed starch into mainly glucose. The excellent physical and chemical properties inlcuding high acidic stability, Ca2+-independent and high maltotriose-forming capacity make AmyE suitable in food and sugar syrup industries. Conclusions This study illustrates that a gene family can encode multiple enzymes members having remarkable differences in biochemical properties. It provides not only new insights into evolution and functional divergence among different members of an α-amylase family, but the development of new enzymes for industrial application.

      PubDate: 2018-02-17T05:33:24Z
      DOI: 10.1016/j.ejbt.2018.01.004
       
 
 
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