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Showing 1 - 200 of 3562 Journals sorted alphabetically
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AADE in Practice     Hybrid Journal   (Followers: 4)
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AIDS Research and Human Retroviruses     Hybrid Journal   (Followers: 8)
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Aktuelle Ernährungsmedizin     Hybrid Journal   (Followers: 4)
Al-Azhar Assiut Medical Journal     Open Access  
Alexandria Journal of Medicine     Open Access   (Followers: 1)
Allgemeine Homöopathische Zeitung     Hybrid Journal   (Followers: 2)
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ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3)
American Journal of Biomedical Engineering     Open Access   (Followers: 11)
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Amyloid: The Journal of Protein Folding Disorders     Hybrid Journal   (Followers: 4)
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Anales de la Facultad de Medicina, Universidad de la República, Uruguay     Open Access  
Anales del Sistema Sanitario de Navarra     Open Access   (Followers: 1)
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Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
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Annals of Ibadan Postgraduate Medicine     Open Access  
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Annals of Medicine     Hybrid Journal   (Followers: 12)
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Annals of Microbiology     Hybrid Journal   (Followers: 10)
Annals of Nigerian Medicine     Open Access   (Followers: 1)
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Annual Review of Medicine     Full-text available via subscription   (Followers: 18)
Anthropological Review     Open Access   (Followers: 24)
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Antibiotics     Open Access   (Followers: 9)
Antibodies     Open Access   (Followers: 2)
Antibody Technology Journal     Open Access   (Followers: 1)
Anuradhapura Medical Journal     Open Access  
Anwer Khan Modern Medical College Journal     Open Access   (Followers: 2)
Apmis     Hybrid Journal   (Followers: 1)
Apparence(s)     Open Access   (Followers: 1)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Medical Informatics     Open Access   (Followers: 11)
Arab Journal of Nephrology and Transplantation     Open Access   (Followers: 1)
Arak Medical University Journal     Open Access  
Archive of Clinical Medicine     Open Access   (Followers: 1)
Archive of Community Health     Open Access  
Archives of Biomedical Sciences     Open Access   (Followers: 7)
Archives of Medical and Biomedical Research     Open Access   (Followers: 3)
Archives of Medical Laboratory Sciences     Open Access   (Followers: 1)
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Archives of Trauma Research     Open Access   (Followers: 2)
Archivos de Medicina (Manizales)     Open Access  
ArgoSpine News & Journal     Hybrid Journal  
Arquivos Brasileiros de Oftalmologia     Open Access  
Arquivos de Ciências da Saúde     Open Access  
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ARS Medica Tomitana     Open Access   (Followers: 1)
Art Therapy: Journal of the American Art Therapy Association     Full-text available via subscription   (Followers: 10)
Arterial Hypertension     Open Access  
Artificial Intelligence in Medicine     Hybrid Journal   (Followers: 12)
Artificial Organs     Hybrid Journal   (Followers: 1)
Asia Pacific Family Medicine     Open Access  
Asia Pacific Journal of Clinical Nutrition     Full-text available via subscription   (Followers: 9)
Asia Pacific Journal of Clinical Trials : Nervous System Diseases     Open Access  
Asian Bioethics Review     Full-text available via subscription   (Followers: 2)
Asian Journal of Cell Biology     Open Access   (Followers: 6)
Asian Journal of Health     Open Access   (Followers: 3)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 2)
Asian Journal of Medical and Pharmaceutical Researches     Open Access   (Followers: 1)
Asian Journal of Medical Sciences     Open Access   (Followers: 1)
Asian Journal of Scientific Research     Open Access   (Followers: 2)
Asian Journal of Transfusion Science     Open Access   (Followers: 2)
Asian Medicine     Hybrid Journal   (Followers: 4)
ASPIRATOR : Journal of Vector-borne Disease Studies     Open Access  
Astrocyte     Open Access  
Atención Familiar     Open Access  
Atención Primaria     Open Access   (Followers: 1)
Audiology - Communication Research     Open Access   (Followers: 8)
Auris Nasus Larynx     Full-text available via subscription  
Australian Coeliac     Full-text available via subscription   (Followers: 2)
Australian Family Physician     Full-text available via subscription   (Followers: 3)
Australian Journal of Medical Science     Full-text available via subscription   (Followers: 1)
Autopsy and Case Reports     Open Access  
Aviation, Space, and Environmental Medicine     Full-text available via subscription   (Followers: 10)
Avicenna     Open Access   (Followers: 2)
Avicenna Journal of Medicine     Open Access   (Followers: 1)
Bangabandhu Sheikh Mujib Medical University Journal     Open Access   (Followers: 1)
Bangladesh Journal of Anatomy     Open Access   (Followers: 1)
Bangladesh Journal of Bioethics     Open Access  
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 3)
Bangladesh Journal of Medical Education     Open Access   (Followers: 2)
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Bangladesh Medical Journal     Open Access  
Bangladesh Medical Journal Khulna     Open Access  
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Basal Ganglia     Hybrid Journal  
Basic Sciences of Medicine     Open Access   (Followers: 2)
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BC Medical Journal     Free  
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Bijzijn XL     Hybrid Journal   (Followers: 1)
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BioDiscovery     Open Access   (Followers: 2)
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Biologics in Therapy     Open Access  
Biology of Sex Differences     Open Access   (Followers: 3)

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Journal Cover Annals of Microbiology
  [SJR: 0.402]   [H-I: 26]   [10 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1590-4261 - ISSN (Online) 1869-2044
   Published by Springer-Verlag Homepage  [2354 journals]
  • Characterization of D -lactic acid, spore-forming bacteria and
           Terrilactibacillus laevilacticus SK5-6 as potential industrial strains
    • Authors: Budsabathip Prasirtsak; Sitanan Thitiprasert; Vasana Tolieng; Suttichai Assabumrungrat; Somboon Tanasupawat; Nuttha Thongchul
      Pages: 763 - 778
      Abstract: In this study, we screened and isolated D-lactic acid-producing bacteria from soil and tree barks collected in Thailand. Among the isolates obtained, Terrilactibacillus laevilacticus SK5-6 exhibited good D-lactate production in the primary screening fermentation (99.27 g/L final lactate titer with 0.90 g/g yield, 1.38 g/L⋅h, and 99.00% D-enantiomer equivalent). Terrilactibacillus laevilacticus SK5-6 is a Gram-positive, endospore-forming, homofermentative D-lactate producer that can ferment a wide range of sugars to produce D-lactate. Unlike the typical D-lactate producers, such as catalase-negative Sporolactobacillus sp., T. laevilacticus SK5-6 possesses catalase activity; therefore, a two-phase fermentation was employed for D-lactate production. During an aerobic preculture stage, a high-density cell mass was rapidly obtained due to aerobic respiration. When transferred to the fermentation stage at the correct physiological stage (inoculum age) and proper concentration of cell mass (inoculum size), T. laevilacticus rapidly converted glucose into D-lactate under anaerobic conditions, resulting in a high final lactate titer (102.22 g/L), high yield (0.84 g/g), and high productivity (2.13 g/L⋅h). When the process conditions were shifted from an aerobic to an anaerobic environment, unlike other lactate-producing bacteria, the mixed acid fermentation route was not activated in the culture of T. laevilacticus SK5-6 during the fermentation stage when some trace oxygen still remained. Our study demonstrates the excellent characteristics of this isolate for D-lactate production; in particular, a high product yield was obtained without byproduct formation. Based on these key characteristics of T. laevilacticus SK5-6, we suggest that this isolate is a novel D-lactate producer for use in industrial fermentation.
      PubDate: 2017-11-01
      DOI: 10.1007/s13213-017-1306-y
      Issue No: Vol. 67, No. 11 (2017)
  • Identification and characterization of genes involved in kojic acid
           biosynthesis in Aspergillus flavus
    • Authors: Hala A. M. Ammar; Ali Y. Srour; Saeid M. Ezzat; Asmaa M. Hoseny
      Pages: 691 - 702
      Abstract: Although Aspergillus flavus is a strong producer strain for kojic acid (KA), up till now there is no report on genes encoding KA. Conversely, KA genes from A. oryzae have been reported, with kojA, kojR and kojT genes, an enzyme gene, a transcription factor and a transporter, respectively, having been cloned and characterized. Thus, in the present study, we aimed to identify and characterize KA genes from A. flavus. To achieve this goal, we first produced by gamma irradiation A. flavus and A. oryzae mutants with improved levels of KA with respect to wild type (WT) strains. Then, we cloned orthologs of A. oryzae kojA, kojR and kojT from A. flavus. Finally, we analyzed the expression levels of KA genes in mutant (MT) and WT strains of both species. The mutants A. flavus HAk1-M2 and A. oryzae HAk2-M26 were found to produce KA at levels 2.5- and 3.02-fold higher than their parent strains after 7–10 days under shaking conditions. The cloned A. flavus genes AFLA_096040, AFLA_096050 and AFLA_096060, exhibited 99–100% similarity to kojA, kojR and kojT genes from A. oryzae, respectively. Gene expression analyses revealed that the expression levels of KA genes nicely overlap with KA levels both in A. flavus and A. oryzae, MT and WT strains. In addition, we cloned the laeA gene, which controls the biosynthesis of secondary metabolites from A. flavus. The results showed that, unlike A. oryzae, the expression of laeA in A. flavus does not correlate with KA biosynthesis. Our findings are of importance and reveal that the gene cluster comprising AFLA_096040, AFLA_096050 and AFLA_096060 is potentially involved in KA biosynthesis.
      PubDate: 2017-10-01
      DOI: 10.1007/s13213-017-1297-8
      Issue No: Vol. 67, No. 10 (2017)
  • Diversity and dynamics stability of bacterial community in traditional
           solid-state fermentation of Qishan vinegar
    • Authors: Xing Gan; Hanlan Tang; Dongdong Ye; Pan Li; Lixin Luo; Weifeng Lin
      Pages: 703 - 713
      Abstract: Qishan vinegar is a typical Chinese fermented cereal product that is prepared using traditional solid-state fermentation (SSF) techniques. The final qualities of the vinegar produced are closely related to the multiple bacteria present during SSF. In the present study, the dynamics of microbial communities and their abundance in Daqu and vinegar Pei were investigated by the combination of high throughput sequencing and quantitative PCR. Results showed that the Enterobacteriales members accounted for 94.7%, 94.6%, and 92.2% of total bacterial sequences in Daqu Q3, Q5, and Q10, respectively. Conversely, Lactobacillales and Rhodospirillales dominated during the acetic acid fermentation (AAF) stage, corresponding to the quantitative PCR results. Lactobacillus, Acetobacter, Weissella, Leuconostoc and Bacillus were the dominant and characteristic bacterial genera of Qishan vinegar during AAF process. Redundancy analysis suggested that Lactobacillales and Rhodospirillales had a positive correlation with humidity and acidity, respectively. These results confirmed that the bacterial community structure could be affected by physiochemical factors, which determined the unique bacterial composition at different fermentation stages and showed batch-to-batch consistency and stability. Therefore, the conformity of bacterial community succession with physiochemical parameters guaranteed the final quality of Qishan vinegar products. This study provided a scientific perspective for the uniformity and stability of Qishan vinegar, and might aid in controlling the manufacturing process.
      PubDate: 2017-10-01
      DOI: 10.1007/s13213-017-1299-6
      Issue No: Vol. 67, No. 10 (2017)
  • Scenedesmus sp. cultivation using commercial-grade ammonium sources
    • Authors: Jimmy Soares; Robson Kriiger Loterio; Rinamara Martins Rosa; Michel Oliveira Santos; Antônio Galvão Nascimento; Nerilson Terra Santos; Thomas Christopher Rhys Williams; Adriano Nunes-Nesi; Marcio Arêdes Martins
      Abstract: The use of commercial-grade nutrients such as agricultural fertilizers is important for commercial microalgae cultivation, and this is particularly the case for biofuel production which is associated with low added value. Nitrogen is a very important macronutrient in microalgae cultivation, and ammonium sources are cheaper than nitrate sources. However, the growth response and cellular composition can be altered by the different nutrient sources. In the study reported here, we investigated the effects of different ammonium doses and commercial-grade macronutrients from agricultural fertilizers on the growth of Scenedesmus sp. BR003, a promising genus for biofuel production. Five growth media were developed using fertilizers and evaluated during Scenedesmus sp. cultivation under autotrophic conditions. The growth media differed in terms of their composition and concentration of macronutrients. We found that all commercial-grade media supported equal or higher cell concentrations, dry weight, water-soluble proteins, neutral carbohydrates, and total lipid production compared to the conventional BG11 medium. However, the commercial-grade growth medium with the highest ammonium content affected the coenobium pattern of Scenedesmus sp. BR003. Commercial-grade nutrient sources were a low-cost alternative to improve the growth of Scenedesmus sp. BR003. The different fertilizers also allowed for manipulation of microalgae chemical composition and phenotypic plasticity to target traits of commercial interest. Our results demonstrate the potential of using ammonium from agricultural fertilizers as a nitrogen source in combination with other commercial-grade macronutrients sources. In addition, this work demonstrates the ability of a robust Scenedesmus strain to grow in media of different compositions, even when a high dosage of ammonium was used.
      PubDate: 2017-12-08
      DOI: 10.1007/s13213-017-1315-x
  • Scenedesmus vacuolatus cultures for possible combined laccase-like
           phenoloxidase activity and biodiesel production
    • Authors: Dora Allegra Carbone; Immacolata Gargano; Pasquale Chiaiese; Antonino Pollio; Raffaele Marotta; Giuseppe Olivieri; Gabriele Pinto
      Abstract: A key aspect of the industrial development of microalgal production processes is the excessive cost of biomass production. A solution is a combination of biodiesel production and wastewater treatment. The microalga Scenedesmus has a high lipid content and a potential extracellular phenoloxidase activity, which could improve the phycoremediation of phenolic pollutants. In this work, the most suitable growth conditions to obtain this twofold aim were analyzed. First, different strains of Scenedesmus vacuolatus microalga were tested at different pH, salinity and CO2 concentration in the gas phase. The two most promising strains were then cultivated in autotrophic and heterotrophic conditions, and were investigated in terms of efficient nitrogen removal, fatty acid profile and maximized extracellular phenoloxidase activity in the medium. The results showed two extreme conditions: (1) biomass productivity doubled when photobioreactors were sparged with 5% CO2 supplemented air with respect to cultures sparged with air (the steady state values of strain 53 were 0.138 g L−1 day−1 in the presence of air, and 0.243 in the presence of CO2 addition), and N-starvation under 5% CO2enhanced the transesterified fraction of lipids (strain 53 FAME fraction in the presence of N-starvation was 33%, in the presence of nitrogen FAME fraction was 22%); (2) phenoloxidase activity was completely suppressed by presence of 5% CO2 in the gas phase (strain 53 0.21 U mL−1), indicating clear catabolite repression for the induction of this enzyme in the algal metabolism.
      PubDate: 2017-12-01
      DOI: 10.1007/s13213-017-1309-8
  • Decrease of N -nitrosodimethylamine and N -nitrosodiethylamine by
           Lactobacillus pentosus R3 is associated with surface-layer proteins
    • Authors: Yaqing Xiao; Peijun Li; Mei Xu; Wu Wang; Conggui Chen
      Abstract: The objective of this study was to evaluate the ability of five strains of meat-borne bacteria to decrease N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) and to elucidate the mechanism in Mann-Rogosa-Sharp (MRS) broth. Lactobacillus pentosus R3 was found to be the most effective in decreasing the concentration of the two N-nitrosamines (NAs) in MRS broth, with a rate of 22.05% for NDMA and 23.31% for NDEA. The concentration of the two NAs could not be reduced by either extracellular metabolites or intracellular extracts of Lb. pentosus R3 (P > 0.05), and proteinaceous substances in the cell debris were found to be responsible for the decrease. These were surface-layer proteins (SLPs) located on the cell wall. Therefore, the decrease in NDMA and NDEA by Lb. pentosus R3 is associated with its SLPs. Lb. pentosus R3 may be developed as a starter culture in the production of fermented foods with lower NAs.
      PubDate: 2017-11-29
      DOI: 10.1007/s13213-017-1314-y
  • In vitro rumen fermentation of soluble and non-soluble polymeric
           carbohydrates in relation to ruminal acidosis
    • Authors: Darwin; Anne Barnes; Ralf Cord-Ruwisch
      Abstract: The end-products of dietary carbohydrate fermentation catalysed by rumen microflora can serve as the primary source of energy for ruminants. However, ruminants provided with continuous carbohydrate-containing feed can develop a metabolic disorder called “acidosis”. We have evaluated the fermentation pattern of both soluble monomeric and non-soluble polymeric carbohydrates in the rumen in in vitro fermentation trials. We found that acidosis could occur within 6 h of incubation in the rumen culture fermenting sugars and starch. The formation of lactic acid and acetic acid, either alone or in mixture with ethanol, accounted for high build-up of acid in the rumen. Acidosis resulted even when only 20% of a normal daily feed load for all soluble and non-soluble carbohydrates was provided. DNA-based microbial analysis revealed that Prevotella was the dominant microbial species present in the rumen fluid.
      PubDate: 2017-11-25
      DOI: 10.1007/s13213-017-1307-x
  • Presence of pathogenic bacteria in ice cubes and evaluation of their
           survival in different systems
    • Authors: Luca Settanni; Raimondo Gaglio; Carlo Stucchi; Simone De Martino; Nicola Francesca; Giancarlo Moschetti
      Abstract: In this study, 60 samples of ice cubes produced at different levels (domestic, restaurant and industrial facilities), within a restricted geographical area, were investigated for their general microbiological characteristics through the analysis of populations other than enteric bacteria. Total mesophilic bacteria were in the range 1.01 × 102–9.55 × 103, 3.12 × 102–6.31 × 103 and 1.30 × 102–3.99 × 103 CFU/100 mL of thawed ice from domestic freezer (DF), stock boxes (SB) for self-production performed with ice machines in bars and pubs, and from sales packages (SP) of industrial productions, respectively. Some DF and SP samples were negative for the presence of total psychrotrophic bacteria, showing that there are no specific microbial groups associated with ice. Pseudomonads were found in the majority of ice samples analyzed. The levels of contamination of the ice samples were significantly different among the three ice cube production levels. The samples produced at domestic level and those collected from bars and pubs were characterised by the highest cell densities. The colonies representative for the different bacterial morphologies were randomly picked up from plates, purified to homogeneity and subjected to the phenotypic and genotypic characterisation. Fifty-two strains representing 31 species of eight bacterial genera were identified, with the most numerous groups included in Pseudomonas, Staphylococcus, Bacillus and Acinetobacter. A consistent percentage of the microorganisms identified from ice are known agents of human infections, and their presence indicate an environmental contamination. In order to evaluate the effectiveness of the ice cubes to transfer pathogenic agents to consumers, a bar consumption was simulated with different drink systems added with ice cubes artificially contaminated with the strains found at dominant levels (Acinetobacter lwoffii ICE100, Bacillus cereus ICE170, Pseudomonas putida ICE224 and Staphylococcus haemolyticus ICE182), and the results showed a consistent reduction of bacterial risk due to alcohol, CO2, pH and antibacterial ingredients of vodka, whisky, Martini, peach tea, tonic water and coke.
      PubDate: 2017-11-18
      DOI: 10.1007/s13213-017-1311-1
  • Safety, probiotic and technological properties of Lactobacilli isolated
           from unpasteurised ovine and caprine cheeses
    • Authors: Dobroslava Bujnakova; Eva Strakova
      Abstract: Eleven Lactobacillus plantarum from Slovak ovine and caprine lump and stored cheeses, and from four commercial probiotic and yogurt cultures (Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus acidophilus) identified using a Maldi-TOF MS analysis were screened in vitro for selected aspects correlated with safety (antibiotic susceptibility patterns, biochemical and haemolytic activity, presence of genes responsible for biogenic amines production), functional traits (including acid, bile tolerance and antimicrobial activity), ecological roles (ability to produce biofilms), and technological applications (acidification and milk coagulation capacity) for assurance of their quality and diversity. The antibiotic susceptibility showed two L. plantarum strains, 19l5 and 18l4, with the presence of the non-wild-type ECOFFs (epidemiological cut-off) for clindamycin and/or gentamicin. All these strains expressed a high acid tolerance at pH 2.5 after a 4 h exposure (bacteria viability varied between 60% and 91%), and bile resistance at 0.3% oxgall ranged from 60% to 99% with no haemolytic activity. Three wild L. plantarum strains, 17l1, 16l4, 18l2, had no harmful metabolic activities, and formed strong biofilms that were measured by a crystal violet assay. Simultaneously, the acid cell-free culture supernatant (ACFCS) from L. plantarum 18l2 had a marked inhibitory effect on the viability of the pathogens as evaluated by flow-cytometry, and also exhibited fast acidification and milk coagulation. As a result, we conclude that L. plantarum 18l2 can be included as part of the created lactobacilli collection that is useful as a starter, or starter adjunct, in the dairy industry, due to its desirable safety and probiotic characteristics, together with rapid acidification capacity compared with other investigated strains from commercially accessible products.
      PubDate: 2017-11-17
      DOI: 10.1007/s13213-017-1310-2
  • Improving isobutanol titers in Saccharomyces cerevisiae with
           over-expressing NADPH-specific glucose-6-phosphate dehydrogenase (Zwf1)
    • Authors: Ruiqi Feng; Jingzhi Li; Aili Zhang
      Abstract: Isobutanol is a more promising biofuel than ethanol due to its higher energy density and lower hygroscopicity. Saccharomyces cerevisiae, as a model eukaryote, has the potential advantage to produce isobutanol because of its greater tolerance to higher alcohols. NADPH is a key cofactor for isobutanol synthesis, and glucose-6-phosphate dehydrogenase (Zwf1) is one of the main NADPH-supplying sources in S. cerevisiae. In this study, we investigated the effects of over-expressing ZWF1 on isobutanol titers. Our results showed that engineered strain HZAL-7023 produced 6.22 mg isobutanol per g glucose, which increased by 6.64-fold compared with the parent strain, while engineered strain HZAL-7023 22-ZWF1 produced 11.46 mg isobutanol per g glucose, which increased by 1.82-fold compared with engineered strain HZAL-7023. These results suggested that improvement of NADPH supply through over-expressing ZWF1 contributed to isobutanol biosynthesis in S. cerevisiae. These results also verified the proposed concept of increasing isobutanol titers in S. cerevisiae by resolving cofactor imbalance. Finally, this study provides a new strategy for enhancing isobutanol biosynthesis.
      PubDate: 2017-11-09
      DOI: 10.1007/s13213-017-1304-0
  • Characterization of phosphate-solubilizing bacteria exhibiting the
           potential for growth promotion and phosphorus nutrition improvement in
           maize ( Zea mays L.) in calcareous soils of Sinaloa, Mexico
    • Authors: Jesús A. Ibarra-Galeana; Claudia Castro-Martínez; Rosario A. Fierro-Coronado; Adolfo D. Armenta-Bojórquez; Ignacio E. Maldonado-Mendoza
      Abstract: Greenhouse bioassays were used to examine the ability of selected strains of the rhizobacteria Sinorhizobium meliloti, Bacillus flexus and B. megaterium to solubilize phosphorus (P) and to affect growth promotion and phosphorus nutrition in maize. These bacterial strains were found to decrease the pH and solubilize some forms of insoluble P, such as tricalcium phosphate and hydroxyapatite, as well as to exhibit acid and alkaline phosphatase enzymatic activities in culture medium, properties that are possibly involved in P solubilization. Inoculation of the strains separately and as a consortium of the three bacteria (S. meliloti, B. flexus and B. megaterium) in P-deficient soil (4.33 w/v P) fertilized without P improved plant height, shoot and root dry weight, as well as P nutrition in the maize plants. Use of the B. flexus and B. megaterium strains separately and in a consortium positively affected several growth parameters and P nutrition in plants supplemented with insoluble P. No effect was observed when pots in which the seedlings were growing were supplied with soluble fertilizer. A second assay using a P-deficient soil (6.64 w/v P) showed that inoculation with the consortium of B. flexus and B. megaterium significantly increased growth and total P content in maize plants. A dose–response P fertilization experiment using sterile P-deficient soil led us to conclude that inoculation to soil of the mixture of B. flexus and B. megaterium may improve P nutrition and growth to a level previously attained by the addition of soluble P-fertilizer at 40 w/v P. A non-sterile experiment showed a beneficial response with B. megaterium but not with B. flexus. We propose utilizing these bacteria in P-deficient alkaline soils in future field trials in order to evaluate their potential as biofertilizers.
      PubDate: 2017-11-02
      DOI: 10.1007/s13213-017-1308-9
  • Type I fimbriae mediate in vitro adherence of porcine F18ac+
           enterotoxigenic Escherichia coli (ETEC)
    • Authors: Qiangde Duan; Rahul Nandre; Mingxu Zhou; Guoqiang Zhu
      Abstract: Type I fimbriae commonly expressed by Escherichia coli mediate initial attachment of bacteria to host epithelial cells. However, the role of type I fimbriae in the adherence of porcine enterotoxigenic E. coli (ETEC) to host receptors is unclear. In this study, we examined the role of type I fimbriae in the adherence and biofilm formation of F18ac+ ETEC by constructing mutant strains with deletion of type I fimbrial major subunit (fimA) or minor subunit (fimH). The data indicated that the isogenic ΔfimA and ΔfimH mutants showed significantly lower adherence to porcine epithelial IPEC-1 and IPEC-J2 cells as compared to the F18ac+ ETEC parent strain. In addition, the adherence of F18ac+ ETEC to both cell lines was blocked by the presence of 0.5% D-mannose in the cell culture medium. In addition, both mutant strains impaired their ability to form biofilm in vitro. Interestingly, the deletion of fimA or fimH genes resulted in remarkable up-regulation of the expression of adhesin involved in diffuse adherence (AIDA-I). These results indicated that type I fimbriae may be required for efficient adherence of F18ac+ ETEC to pig epithelial cells and, perhaps, biofilm formation.
      PubDate: 2017-10-24
      DOI: 10.1007/s13213-017-1305-z
  • Differential response of single and co-inoculation of Rhizobium
           leguminosarum and Mesorhizobium ciceri for inducing water deficit stress
           tolerance in wheat
    • Authors: Sana Ullah; Muhammad Yahya Khan; Hafiz Naeem Asghar; Muhammed Javed Akhtar; Zahir Ahmad Zahir
      Abstract: Limited soil water availability is a major threat to agricultural productivity because it inhibits plant growth and yields. Various strategies have been adopted to mitigate water deficit stress in plants; however, using extremophilic microbes with plant growth promoting traits could be an environmentally friendly and cost-effective approach to improve crop stress resilience. Rhizobia are well known for their symbiotic association with legumes, but they can also improve the fitness of non-legumes under stressed conditions. Thus, different rhizobial strains were isolated from nodules of two legumes (lentil and chickpea) and tested for osmoadaptation at four different polyethylene glycol (PEG-6000) levels, i.e., − 0.05, − 0.65, − 1.57, and − 2.17 MPa. Two stress-tolerant rhizobial strains, SRL5 and SRC8, were selected to evaluate their potential to induce tolerance against water deficits in wheat grown at four different percentages of field capacity (FC; 40, 60, 80, and 100%). Rhizobial inoculation improved physiological parameters and growth of wheat under water deficit; however, co-inoculation of selected rhizobia was better than sole application. Grain yield was most limited at the highest level of water deficit but sole inoculation with SRC8 and SRL5 improved yield by 24% and 19%, respectively. Combined inoculation increased grain yield by up to 48% compared to the uninoculated control. Thus, rhizobia from different legumes possess enormous potential for improving the resilience of cereals (non-legumes) to water deficit stress. Moreover, co-inoculation of rhizobia could be more beneficial than their sole application.
      PubDate: 2017-10-12
      DOI: 10.1007/s13213-017-1302-2
  • Diversity and dynamics of the DNA and cDNA-derived bacterial compost
           communities throughout the Agaricus bisporus mushroom cropping process
    • Authors: Conor Francis Mcgee; Helen Byrne; Aisling Irvine; Jude Wilson
      Abstract: The cultivation of Agaricus bisporus involves the conversion of agricultural materials via fermentation into utilisable simple sugars as a nutrient source for the fungal crop during mushroom cropping. However, little is currently known about the role of the bacterial community contributing to the fermentation process. In this investigation we characterised the composition and dynamics of the DNA and cDNA-derived bacterial populations throughout a commercial mushroom cropping process using MiSeq sequencing. Both methods indicated substantial changes in the bacterial community structure after the first flush of the mushroom crop. However, differences were observed between the composition of the bacterial community determined by each of the two methods. The cDNA-derived community indicated that thermotolerant genera with known sulphur-reducing characteristics were highly active up to the first flush. Activity of the phyla Actinobacteria and Firmicutes was observed to increase as fermentation progressed, indicating that the members of these phyla played prominent roles in the conversion of wheat straw into utilisable sugars. The cDNA-derived community comprised genera with roles in the nitrification process that became highly active at post flush 1. Subsequent chemical analysis of extractable nitrate indicated that substantial nitrification occurred up until the termination of the cropping process. This study has demonstrated that a highly dynamic bacterial community is present throughout the mushroom cropping process.
      PubDate: 2017-10-11
      DOI: 10.1007/s13213-017-1303-1
  • Statistically optimized production and characterization of vanillin from
           creosol using newly isolated Klebsiella pneumoniae P27
    • Authors: Geetanjali T. Mali; Pramod J. Kasabe; Padma Babulal Dandge
      Abstract: The current research study deals with the screening of a potent vanillin-producing microorganism among 96 isolated strains. Biochemical characterization and molecular identification confirmed that the isolated strain belongs to the Klebsiella pneumoniae bacteria, so it was denoted as Klebsiella pneumoniae P27. The optimization of medium components for the enhanced production of vanillin was carried out using two-stage statistical experimental designs, in which the significant medium components for vanillin production were screened using a Plackett-Burman experimental design. And the optimal levels of those noteworthy factors were determined by using central composite design. The statistical optimization of medium components resulted in increases in vanillin production and vanillyl alcohol oxidase activity of 2.05-fold and 3.055-fold, respectively. The highest vanillin production (30.88 mg/L) and vanillyl alcohol oxidase activity (0.044 U/mL) was observed after 16 h of incubation in the presence of 0.26 mL/L creosol, 8.06 g/L yeast extract and 2.77 g/L NH4NO3 in the production medium. The optimally produced vanillin was extracted and confirmed using FTIR and LCMS spectral analysis. The results of the current study support a statistical process optimization approach as a potential technique for the enhanced production of vanillin from creosol by using newly isolated Klebsiella pneumoniae P27 bacterial strain.
      PubDate: 2017-10-04
      DOI: 10.1007/s13213-017-1300-4
  • Green bio-dispersant removal efficacy estimation for controlling biofilms
           in cooling towers
    • Authors: Francesca Di Pippo; Francesca de Tora; Luciana Di Gregorio; Marco Buccolini; Rossano Capocecera; Simona Rossetti; Valter Tandoi
      Abstract: In this study the effect of green bio-dispersants on cooling water biofilm attachment has been investigated. As monitoring biofilm growth in industrial cooling systems is extremely complex and difficult, we developed a simple method to additively evaluate the effectiveness of green bio-dispersants on biofilms grown in two different lab-scale systems using, as inoculum, make-up water from an industrial cooling tower. The proposed method uses spectrophotometry to estimate the detached biomass after bio-dispersant action. The biofilm detachment rate and the removal percentage of biofilm were calculated after the use of six green bio-dispersants, two non-green dispersants and three controls at two different concentrations. Under all tested conditions, green bio-dispersants showed higher biofilm removal percentage and detachment rate than non-green additives. These results suggest that highly performing green additives could be recommended as a reasonable replacement for non-green additives for controlling biofilms in cooling towers, in accordance to the European Union’s REACH regulation.
      PubDate: 2017-10-03
      DOI: 10.1007/s13213-017-1301-3
  • Effect of trace elements and optimization of their composition for the
           nitrification of a heterotrophic nitrifying bacterium, Acinetobacter
           harbinensis HITLi7 T , at low temperature
    • Authors: Zejia Zheng; Weiguang Li; Xiaofei Huang; Wen Qin
      Abstract: The effects of trace elements on ammonium degradation performance and extracellular polymeric substances (EPS) secretion of Acinetobacter harbinensis HITLi7T at low temperature were investigated. Response surface methodology (RSM) was applied to obtain the optimal composition of trace elements and analyze their correlation. In this study, the results indicated that the ammonium removal performance could be enhanced by the presence of 0.1 mg L−1 Fe, Mn, or B in pure cultivation. When the concentrations of Fe and Mn were 0.2 mg L−1, the ammonium removal rates of the novel strain HITLi7T were 0.49 ± 0.01 mg L−1·h−1 and 0.58 ± 0.01 mg L−1·h−1, respectively, while it was the low concentration of 0.05 mg L−1 B that showed the maximum ammonium removal rate (0.56 ± 0.02 mg L−1·h−1) of strain HITLi7T. The regression model was obtained and the optimal formulation of trace elements was: B 0.064 mg L−1, Fe 0.12 mg L−1, and Mn 0.1 mg L−1. Based on these values, the experimental ammonium removal rate could reach 0.59 mg L−1·h−1, which matched well with the predicted response. The study also found that the addition of trace elements, causing high ammonium removal rates, resulted in a high polysaccharide (PS) ratio in the EPS secreted by Acinetobacter harbinensis HITLi7T. Especially under the optimal conditions, the PS ratio reached the highest value of 49.9%.
      PubDate: 2017-10-03
      DOI: 10.1007/s13213-017-1298-7
  • Modulation of proline metabolic gene expression in Arabidopsis thaliana
           under water-stressed conditions by a drought-mitigating Pseudomonas putida
    • Authors: Daipayan Ghosh; Sunetra Sen; Sridev Mohapatra
      Abstract: Although amelioration of drought stress in plants by plant growth promoting rhizobacteria (PGPR) is a well reported phenomenon, the molecular mechanisms governing it are not well understood. We have investigated the role of a drought ameliorating PGPR strain, Pseudomonas putida GAP-P45 on the regulation of proline metabolic gene expression in Arabidopsis thaliana under water-stressed conditions. Indeed, we found that Pseudomonas putida GAP-P45 alleviates the effects of water-stress in A. thaliana by drastic changes in proline metabolic gene expression profile at different time points post stress induction. Quantitative real-time expression analysis of proline metabolic genes in inoculated plants under water-stressed conditions showed a delayed but prolonged up-regulation of the expression of genes involved in proline biosynthesis, i.e., ornithine-Δ-aminotransferase (OAT), Δ 1 -pyrroline-5-carboxylate synthetase1 (P5CS1), Δ 1 -pyrroline-5-carboxylate reductase (P5CR), as well as proline catabolism, i.e., proline dehydrogenase1 (PDH1) and Δ 1 -pyrroline-5-carboxylate dehydrogenase (P5CDH). These observations were positively correlated with morpho-physiological evidences of water-stress mitigation in the plants inoculated with Pseudomonas putida GAP-P45 that showed better growth, increased fresh weight, enhanced plant water content, reduction in primary root length, enhanced chlorophyll content in leaves, and increased accumulation of endogenous proline. Our observations point towards PGPR-mediated enhanced proline turnover rate in A. thaliana under dehydration conditions.
      PubDate: 2017-08-24
      DOI: 10.1007/s13213-017-1294-y
  • A physiological comparative study of acid tolerance of Lactobacillus
           plantarum ZDY 2013 and L. plantarum ATCC 8014 at membrane and cytoplasm
    • Authors: Yilin Guo; Ximei Tian; Renhui Huang; Xueying Tao; Nagendra P. Shah; Hua Wei; Cuixiang Wan
      Abstract: This study aimed to disclose the acid tolerance mechanism of Lactobacillus plantarum by comparing L. plantarum ZDY 2013 with the type strain L. plantarum ATCC 8014 in terms of cell membrane, energy metabolism, and amino acid metabolism. L. plantarum ZDY 2013 had a superior growth performance under acidic condition with 100-fold higher survival rate than that of L. plantarum ATCC 8014 at pH 2.5. To determine the acid tolerance physiological mechanism, cell integrity was investigated through scanning electron microscopy. The study revealed that L. plantarum ZDY 2013 maintained cell morphology and integrity, which is much better than L. plantarum ATCC 8014 under acid stress. Analysis of energy metabolism showed that, at pH 5.0, L. plantarum ZDY 2013 enhanced the activity of Na+/K+-ATPase and decreased the ratio of NAD+/NADH in comparison with L. plantarum ATCC 8014. Similarly, amino acid metabolism of intracellular arginine, glutamate, and alanine was improved in L. plantarum ZDY 2013. Correspondingly, the activity of arginine deiminase and glutamate decarboxylase of L. plantarum ZDY 2013 increased by 1.2-fold and 1.3-fold compared with L. plantarum ATCC 8014 in acid stress. In summary, it is demonstrated that the special physiological behaviors (integrity of cell membrane, enhanced energy metabolism, increased amino acid and enzyme level) of L. plantarum ZDY 2013 can protect the cells from acid stress.
      PubDate: 2017-08-23
      DOI: 10.1007/s13213-017-1295-x
  • Bacterial diversity of the outflows of a Polichnitos (Lesvos, Greece) hot
           spring, laboratory studies of a Cyanobacterium sp. strain and potential
           medical applications
    • Authors: Panagiotis Mizerakis; Panagiota Stathopoulou; George Tsiamis; Mohammed N. Baeshen; Jazem A. Mahyoub; Ahmed M. Elazzazy; Stamatia Bellou; Eleni Sakoulogeorga; Irene-Eva Triantaphyllidou; Theodora Mazioti; Panagiotis Katsoris; George Aggelis
      Abstract: The bacterial diversity of the outflows of Polichnitos (Lesvos, Greece) hot spring has been investigated. Cyanobacteria showing high sequence homologies with Phormidium sp. and Cyanobacterium aponinum were found. Members of the Alphaproteobacteria closely related to Rhodobium sp. Albidovulum sp., Rhodobacter sp., Microvigra sp., Nitratireductor sp. and Phaeobacter sp. Gammaproteobacteria, Betaproteobacteria and Firmicutes were represented by members of Idiomarina sp., Marinobacter sp., Shinella sp., Bacillus sp. and Clostridium sp. with sequence homologies ranging from 92% to 100%. Members of the Bacteroidetes and Planctomycetes were represented by sequences of novel phylogenetic linkages exhibiting 87–90% sequence homology with type strains. When the hot spring consortium was cultivated in bioreactor repeated batch culture under photo-autotrophic growth conditions at temperature < 30 °C, Cyanobacterium sp. dominated over Phormidium sp. Cyanobacterium sp. seems to have biotechnological potential since its extracellular broth exhibited a strong insecticidal activity against larvae of Aedes aegypti (a vector of important human diseases) and significant anti-cancer activity against the PC3 human prostate cancer cell line, while its toxicity against human endothelial cells was relatively low.
      PubDate: 2017-08-21
      DOI: 10.1007/s13213-017-1293-z
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