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Publisher: Springer-Verlag (Total: 2350 journals)

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Showing 1 - 200 of 2350 Journals sorted alphabetically
3D Printing in Medicine     Open Access  
3D Research     Hybrid Journal   (Followers: 21, SJR: 0.222, CiteScore: 1)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 10, SJR: 0.825, CiteScore: 1)
AAPS J.     Hybrid Journal   (Followers: 22, SJR: 1.118, CiteScore: 4)
AAPS PharmSciTech     Hybrid Journal   (Followers: 7, SJR: 0.752, CiteScore: 3)
Abdominal Imaging     Hybrid Journal   (Followers: 14, SJR: 0.866, CiteScore: 2)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4, SJR: 0.439, CiteScore: 0)
Academic Psychiatry     Full-text available via subscription   (Followers: 23, SJR: 0.53, CiteScore: 1)
Academic Questions     Hybrid Journal   (Followers: 8, SJR: 0.106, CiteScore: 0)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26, SJR: 0.316, CiteScore: 1)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.359, CiteScore: 1)
Acoustics Australia     Hybrid Journal   (SJR: 0.232, CiteScore: 1)
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.367, CiteScore: 0)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.675, CiteScore: 1)
Acta Biotheoretica     Hybrid Journal   (Followers: 4, SJR: 0.284, CiteScore: 1)
Acta Diabetologica     Hybrid Journal   (Followers: 17, SJR: 1.587, CiteScore: 3)
Acta Endoscopica     Hybrid Journal   (Followers: 1)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.769, CiteScore: 1)
Acta Geochimica     Hybrid Journal   (Followers: 6, SJR: 0.24, CiteScore: 1)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 2, SJR: 0.305, CiteScore: 1)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.588, CiteScore: 3)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.517, CiteScore: 1)
Acta Mathematica     Hybrid Journal   (Followers: 12, SJR: 7.066, CiteScore: 3)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.452, CiteScore: 1)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.379, CiteScore: 1)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.27, CiteScore: 0)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.208, CiteScore: 0)
Acta Mechanica     Hybrid Journal   (Followers: 21, SJR: 1.04, CiteScore: 2)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.607, CiteScore: 2)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7, SJR: 0.576, CiteScore: 2)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.638, CiteScore: 1)
Acta Neurochirurgica     Hybrid Journal   (Followers: 6, SJR: 0.822, CiteScore: 2)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 1, SJR: 0.376, CiteScore: 1)
Acta Neuropathologica     Hybrid Journal   (Followers: 5, SJR: 7.589, CiteScore: 12)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.334, CiteScore: 1)
Acta Parasitologica     Hybrid Journal   (Followers: 10, SJR: 0.641, CiteScore: 1)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.574, CiteScore: 2)
Acta Politica     Hybrid Journal   (Followers: 14, SJR: 0.605, CiteScore: 1)
Activitas Nervosa Superior     Hybrid Journal   (SJR: 0.147, CiteScore: 0)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 6, SJR: 0.103, CiteScore: 0)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 23, SJR: 0.72, CiteScore: 2)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 16, SJR: 1.005, CiteScore: 2)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.703, CiteScore: 2)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4, SJR: 0.698, CiteScore: 1)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 37, SJR: 0.956, CiteScore: 2)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19, SJR: 0.812, CiteScore: 1)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51, SJR: 1.09, CiteScore: 1)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.144, CiteScore: 0)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 28, SJR: 1.64, CiteScore: 2)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.475, CiteScore: 2)
Advances in Polymer Science     Hybrid Journal   (Followers: 43, SJR: 1.04, CiteScore: 3)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 1.075, CiteScore: 3)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.517, CiteScore: 1)
Aerobiologia     Hybrid Journal   (Followers: 3, SJR: 0.673, CiteScore: 2)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 9, SJR: 0.825, CiteScore: 1)
African Archaeological Review     Hybrid Journal   (Followers: 16, SJR: 0.862, CiteScore: 1)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.235, CiteScore: 0)
AGE     Hybrid Journal   (Followers: 7)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.39, CiteScore: 1)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.67, CiteScore: 2)
Agricultural Research     Hybrid Journal   (Followers: 4, SJR: 0.276, CiteScore: 1)
Agriculture and Human Values     Hybrid Journal   (Followers: 14, SJR: 1.173, CiteScore: 3)
Agroforestry Systems     Hybrid Journal   (Followers: 19, SJR: 0.663, CiteScore: 1)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 12, SJR: 1.864, CiteScore: 6)
AI & Society     Hybrid Journal   (Followers: 8, SJR: 0.227, CiteScore: 1)
AIDS and Behavior     Hybrid Journal   (Followers: 14, SJR: 1.792, CiteScore: 3)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.862, CiteScore: 3)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 5, SJR: 0.531, CiteScore: 0)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.583, CiteScore: 1)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 1.095, CiteScore: 1)
Algorithmica     Hybrid Journal   (Followers: 9, SJR: 0.56, CiteScore: 1)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.234, CiteScore: 0)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 1.11, CiteScore: 3)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3)
AMBIO     Hybrid Journal   (Followers: 11, SJR: 1.569, CiteScore: 4)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 16, SJR: 0.951, CiteScore: 3)
American J. of Community Psychology     Hybrid Journal   (Followers: 28, SJR: 1.329, CiteScore: 2)
American J. of Criminal Justice     Hybrid Journal   (Followers: 8, SJR: 0.772, CiteScore: 1)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 15, SJR: 0.46, CiteScore: 1)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.181, CiteScore: 0)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.611, CiteScore: 1)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 21, SJR: 0.314, CiteScore: 0)
American Sociologist     Hybrid Journal   (Followers: 12, SJR: 0.35, CiteScore: 0)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.135, CiteScore: 3)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7, SJR: 0.211, CiteScore: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 5, SJR: 0.536, CiteScore: 1)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 5)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 32, SJR: 0.978, CiteScore: 3)
Anatomical Science Intl.     Hybrid Journal   (Followers: 2, SJR: 0.367, CiteScore: 1)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.177, CiteScore: 5)
Animal Cognition     Hybrid Journal   (Followers: 19, SJR: 1.389, CiteScore: 3)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.192, CiteScore: 0)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.097, CiteScore: 2)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4, SJR: 0.438, CiteScore: 0)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.429, CiteScore: 0)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.197, CiteScore: 1)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.042, CiteScore: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 4, SJR: 0.932, CiteScore: 1)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.85, CiteScore: 2)
Annals of Finance     Hybrid Journal   (Followers: 30, SJR: 0.579, CiteScore: 1)
Annals of Forest Science     Hybrid Journal   (Followers: 7, SJR: 0.986, CiteScore: 2)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.228, CiteScore: 1)
Annals of Hematology     Hybrid Journal   (Followers: 16, SJR: 1.043, CiteScore: 2)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12, SJR: 0.413, CiteScore: 1)
Annals of Microbiology     Hybrid Journal   (Followers: 10, SJR: 0.479, CiteScore: 2)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 4, SJR: 0.687, CiteScore: 2)
Annals of Operations Research     Hybrid Journal   (Followers: 10, SJR: 0.943, CiteScore: 2)
Annals of Ophthalmology     Hybrid Journal   (Followers: 11)
Annals of Regional Science     Hybrid Journal   (Followers: 7, SJR: 0.614, CiteScore: 1)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 9, SJR: 0.239, CiteScore: 1)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 14, SJR: 1.986, CiteScore: 4)
Annals of Telecommunications     Hybrid Journal   (Followers: 9, SJR: 0.223, CiteScore: 1)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 1.495, CiteScore: 1)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.834, CiteScore: 2)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.22, CiteScore: 3)
APOPTOSIS     Hybrid Journal   (Followers: 8, SJR: 1.424, CiteScore: 4)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.294, CiteScore: 1)
Applications of Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.602, CiteScore: 1)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43, SJR: 0.571, CiteScore: 2)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17, SJR: 0.21, CiteScore: 1)
Applied Cancer Research     Open Access  
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.49, CiteScore: 0)
Applied Composite Materials     Hybrid Journal   (Followers: 49, SJR: 0.58, CiteScore: 2)
Applied Entomology and Zoology     Partially Free   (Followers: 3, SJR: 0.422, CiteScore: 1)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.733, CiteScore: 3)
Applied Geophysics     Hybrid Journal   (Followers: 8, SJR: 0.488, CiteScore: 1)
Applied Intelligence     Hybrid Journal   (Followers: 12, SJR: 0.6, CiteScore: 2)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.319, CiteScore: 1)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 6, SJR: 0.886, CiteScore: 1)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.17, CiteScore: 0)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.461, CiteScore: 1)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 63, SJR: 1.182, CiteScore: 4)
Applied Physics A     Hybrid Journal   (Followers: 9, SJR: 0.481, CiteScore: 2)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 24, SJR: 0.74, CiteScore: 2)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.519, CiteScore: 2)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 12, SJR: 0.316, CiteScore: 1)
Applied Solar Energy     Hybrid Journal   (Followers: 18, SJR: 0.225, CiteScore: 0)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4, SJR: 0.542, CiteScore: 1)
Aquaculture Intl.     Hybrid Journal   (Followers: 22, SJR: 0.591, CiteScore: 2)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 1)
Aquatic Ecology     Hybrid Journal   (Followers: 33, SJR: 0.656, CiteScore: 2)
Aquatic Geochemistry     Hybrid Journal   (Followers: 4, SJR: 0.591, CiteScore: 1)
Aquatic Sciences     Hybrid Journal   (Followers: 13, SJR: 1.109, CiteScore: 3)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.303, CiteScore: 1)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 2, SJR: 0.319, CiteScore: 1)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 20, SJR: 1.052, CiteScore: 2)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.224, CiteScore: 0)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.725, CiteScore: 1)
Archival Science     Hybrid Journal   (Followers: 59, SJR: 0.745, CiteScore: 2)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 8, SJR: 0.186, CiteScore: 1)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 2, SJR: 0.909, CiteScore: 1)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 3.93, CiteScore: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.79, CiteScore: 2)
Archives and Museum Informatics     Hybrid Journal   (Followers: 145, SJR: 0.101, CiteScore: 0)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5, SJR: 1.41, CiteScore: 5)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 1.006, CiteScore: 2)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14, SJR: 0.773, CiteScore: 2)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 16, SJR: 0.956, CiteScore: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.644, CiteScore: 2)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.146, CiteScore: 2)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 0.71, CiteScore: 2)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 10, SJR: 1.493, CiteScore: 3)
Archives of Toxicology     Hybrid Journal   (Followers: 17, SJR: 1.541, CiteScore: 5)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 0.973, CiteScore: 2)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 14, SJR: 1.274, CiteScore: 3)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 0.946, CiteScore: 3)
ArgoSpine News & J.     Hybrid Journal  
Argumentation     Hybrid Journal   (Followers: 5, SJR: 0.349, CiteScore: 1)
Arid Ecosystems     Hybrid Journal   (Followers: 2, SJR: 0.2, CiteScore: 0)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.766, CiteScore: 1)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1, SJR: 0.355, CiteScore: 0)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.839, CiteScore: 2)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.131, CiteScore: 0)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 11, SJR: 0.937, CiteScore: 2)
Artificial Intelligence Review     Hybrid Journal   (Followers: 14, SJR: 0.833, CiteScore: 4)
Artificial Life and Robotics     Hybrid Journal   (Followers: 9, SJR: 0.226, CiteScore: 0)
Asia Europe J.     Hybrid Journal   (Followers: 5, SJR: 0.504, CiteScore: 1)
Asia Pacific Education Review     Hybrid Journal   (Followers: 12, SJR: 0.479, CiteScore: 1)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 16, SJR: 1.185, CiteScore: 2)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 12, SJR: 0.353, CiteScore: 1)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.187, CiteScore: 0)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 19, SJR: 0.855, CiteScore: 1)
Asian Business & Management     Hybrid Journal   (Followers: 9, SJR: 0.378, CiteScore: 1)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 9)
Asian J. of Criminology     Hybrid Journal   (Followers: 5, SJR: 0.543, CiteScore: 1)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 2, SJR: 0.548, CiteScore: 1)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.183, CiteScore: 0)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  

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Journal Cover
Applied Microbiology and Biotechnology
Journal Prestige (SJR): 1.182
Citation Impact (citeScore): 4
Number of Followers: 63  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1432-0614 - ISSN (Online) 0175-7598
Published by Springer-Verlag Homepage  [2350 journals]
  • A Pichia pastoris single-cell biosensor for detection of enzymatically
           produced methanol
    • Authors: Tomoyuki Takeya; Hiroya Yurimoto; Yasuyoshi Sakai
      Abstract: We conducted single-cell analyses of the methylotrophic yeast Pichia pastoris to develop a biosensor for the detection of methanol produced by heterologous enzymes. In this biosensor, methanol and its subsequent metabolism induce expression of a gene encoding a fluorescent protein that was placed under the control of a methanol-inducible promoter. Using quantitative analyses of fluorescence microscopy images, a methanol-inducible promoter and a host strain were selected, and preculture and assay conditions were optimized to improve the methanol detection limit. Fluorescence-activated cell sorting (FACS) analysis of the distribution and geometric mean of cellular fluorescence intensity against various concentrations of methanol revealed a detection limit of 2.5 μM. Finally, this biosensor was applied to evaluate the activity of a heterologously expressed pectin methylesterase (PME). The cellular fluorescence intensity was proportional to the copy number of the PME expression cassette, the protein level, and the enzyme activity. This biosensor can be used for high-throughput screening of single cells harboring high methanol-producing activity, and thereby, the development of a bioconversion process using methanol-producing enzymes.
      PubDate: 2018-06-11
      DOI: 10.1007/s00253-018-9144-9
  • Mycobacterium tuberculosis toxin Rv2872 is an RNase involved in vancomycin
           stress response and biofilm development
    • Authors: Xiaoyu Wang; Xiaokang Zhao; Hao Wang; Xue Huang; Xiangke Duan; Yinzhong Gu; Nzungize Lambert; Ke Zhang; Zhenhao Kou; Jianping Xie
      Abstract: Bacterial toxin–antitoxin (TA) systems are emerging important regulators of multiple cellular physiological events and candidates for novel antibiotic targets. To explore the role of Mycobacterium tuberculosis function, unknown toxin gene Rv2872 was heterologously expressed in Mycobacterium smegmatis (MS_Rv2872). Upon induction, MS_Rv2872 phenotype differed significantly from the control, such as increased vancomycin resistance, retarded growth, cell wall, and biofilm structure. This phenotype change might result from the RNase activity of Rv2872 as purified Rv2872 toxin protein can cleave the products of several key genes involved in abovementioned phenotypes. In summary, toxin Rv2872 was firstly reported to be a endonuclease involved in antibiotic stress responses, cell wall structure, and biofilm development.
      PubDate: 2018-06-11
      DOI: 10.1007/s00253-018-9132-0
  • C-terminal Ser/Thr residues are vital for the regulatory role of Ste7 in
           the asexual cycle and virulence of Beauveria bassiana
    • Authors: Zhi-Kang Wang; Qing Cai; Sen-Miao Tong; Sheng-Hua Ying; Ming-Guang Feng
      Abstract: The mitogen-activated protein kinase (MAPK) kinase Ste7 has a conserved Ser/Thr loop (S/T-X4(6)-S/T) that can activate the MAPK Fus3 or Kss1 for the regulation of pheromone response and filamentous growth in model yeast. Here, we show that not only the loop but also four C-terminal Ser/Thr residues are essential for Ste7 to function in the Fus3 cascade of Beauveria bassiana, a filamentous fungal insect pathogen. Mutagenesis of either looped S216/T220 or C-terminal S362 resulted in the same severe defects in conidial germination, hyphal growth, aerial conidiation, and submerged blastospore production as the ste7 deletion, followed by a complete loss of virulence and similarly increased cell sensitivities to osmotic salts, oxidants, heat shock and UV-B irradiation. Mutagenesis of three other Ser/Thr residues (S391, S440, and T485) also caused severe defects in most of the mentioned phenotypes. These defects correlated well with dramatically reduced transcript levels of some phenotype-related genes. These genes encode a transcription factor (CreA) essential for carbon/nitrogen assimilation, developmental activators (BrlA, AbaA, and WetA) and upstream transcription factor (FluG) required for conidiation, P-type N+/K+ ATPases (Ena1–5) required for intracellular N+/K+ homeostasis, and antioxidant enzymes involved in multiple stress responses. Our study unveils that the loop and four C-terminal Ser/Thr residues are all vital for the regulatory role of Ste7 in the growth, conidiation, virulence, and/or stress tolerance of B. bassiana and perhaps other filamentous fungi.
      PubDate: 2018-06-11
      DOI: 10.1007/s00253-018-9148-5
  • Polymeric solvent engineering for gram/liter scale production of a
           water-insoluble isoflavone derivative, ( S )-equol
    • Authors: Pyung-Gang Lee; Sang-Hyuk Lee; Joonwon Kim; Eun-Jung Kim; Kwon-Young Choi; Byung-Gee Kim
      Abstract: A potent phytoestrogen, (S)-equol, is a promising isoflavone derivative drawing our great attention owing to its various biological and clinical benefits. Through selective activation of the estrogen receptor ERβ or androgen receptor, (S)-equol reduces menopausal symptoms, osteoporosis, skin aging, hair loss, and incidence of prostate or ovarian cancers without adverse effects. Traditional biosynthesis of (S)-equol exploited non-productive natural equol-producing anaerobic bacteria that mainly belong to Coriobacteriaceae isolated from human intestine. Recently, we developed a recombinant Escherichia coli strain which could convert daidzein into (S)-equol effectively under an aerobic condition. However, the yield was limited up to about the 200 mg/L level due to unknown reasons. In this study, we identified that the bottleneck of the limited production was the low solubility of isoflavone (i.e., 2.4 mg/L) in the reaction medium. In order to solve the solubility problem without harmful effect to the whole-cell catalyst, we applied commercial hydrophilic polymers (HPs) and a polar aprotic co-solvent in the reaction medium. Among the examined water-soluble polymers, polyvinylpyrrolidone (PVP)-40k was verified as the most promising supplement which increased daidzein solubility by 40 times and (S)-equol yield up to 1.22 g/L, the highest ever reported and the first g/L level biotransformation. Furthermore, PVP-40k was verified to significantly increase the solubilities of other water-insoluble natural polyphenols in aqueous solution. We suggest that addition of both HP and polar aprotic solvent in the reaction mixture is a powerful alternative to enhance production of polyphenolic chemicals rather than screening appropriate organic solvents for whole-cell catalysis of polyphenols.
      PubDate: 2018-06-09
      DOI: 10.1007/s00253-018-9137-8
  • Effective management of soft rot of ginger caused by Pythium spp. and
           Fusarium spp.: emerging role of nanotechnology
    • Authors: Mahendra Rai; Avinash P. Ingle; Priti Paralikar; Netravati Anasane; Rajendra Gade; Pramod Ingle
      Abstract: Ginger (Zingiber officinale Rosc.) is a tropical plant cultivated all over the world due to its culinary and medicinal properties. It is one of the most important spices commonly used in food, which increases its commercial value. However, soft rot (rhizome rot) is a common disease of ginger caused by fungi such as Pythium and Fusarium spp. It is the most destructive disease of ginger, which can reduce the production by 50 to 90%. Application of chemical fungicides is considered as an effective method to control soft rot of ginger but extensive use of fungicides pose serious risk to environmental and human health. Therefore, the development of ecofriendly and economically viable alternative approaches for effective management of soft rot of ginger such diseases is essentially required. An acceptable approach that is being actively investigated involves nanotechnology, which can potentially be used to control Pythium and Fusarium. The present review is aimed to discuss worldwide status of soft rot associated with ginger, the traditional methods available for the management of Pythium and Fusarium spp. and most importantly, the role of various nanomaterials in the management of soft rot of ginger. Moreover, possible antifungal mechanisms for chemical fungicides, biological agents and nanoparticles have also been discussed.
      PubDate: 2018-06-09
      DOI: 10.1007/s00253-018-9145-8
  • Polyacrylonitrile (PAN) nanofibres spun with copper nanoparticles: an
           anti- Escherichia coli membrane for water treatment
    • Authors: J. J. Ahire; D. P. Neveling; L. M. T. Dicks
      Abstract: Copper nanoparticles (CNPs) were mixed with polyacrylonitrile (PAN) and electrospun into nanofibres (CuPAN nanofibres). PAN nanofibres containing 1.0, 3.0 and 5.0% copper (w/v) displayed beads-on-string morphology with protrusions of copper particles. The diameter of the CuPAN nanofibres differed according to the copper content, ranging from 386 nm (1.0%, w/v, copper) to 922 nm (5.0%, w/v, copper). No chemical interaction of copper with PAN was observed when studied with X-ray diffraction, ATR-FTIR (attenuated total reflection-Fourier transform infrared) spectroscopy and TGA (thermogravimetric analysis). None of the CuPAN nanofibres showed signs of degradation after 7 days in water. Bacteria suspended in random mobility buffer and filtered through a 3% CuPAN nanofibre membrane (25 mm diameter, 75–80 μm thickness), at a filtration rate of 20 ml min−1, reduced the cell numbers of enterotoxigenic Escherichia coli (ETEC) from 3.3 × to 2.1 × 106 cfu ml−1 and methicillin-resistant Staphylococcus aureus (MRSA) from 1.2 × 10 to 1.3 × 103 cfu ml−1. Membranes produced with 1.0, 3.0 and 5.0% (w/v) CuPAN inhibited the growth of enteroaggregative E. coli (EAEC), enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), ETEC and MRSA, as shown with LIVE/DEAD™ BacLight™ staining. Real-time bactericidal activity of CuPAN membranes was recorded by staining the cells with SYTO 9 and PI, followed by flow cytometry. Filter membranes made from CuPAN fibres may be used to reduce pathogenic E. coli cell numbers in potable water.
      PubDate: 2018-06-08
      DOI: 10.1007/s00253-018-9051-0
  • Short, auto-inducible promoters for well-controlled protein expression in
           Escherichia coli
    • Authors: Ona Anilionyte; Hong Liang; Xiaoqiang Ma; Liming Yang; Kang Zhou
      Abstract: Expression of recombinant proteins in Escherichia coli often requires use of inducible promoters to shorten the lag phase and improve protein productivity and final protein titer. Synthetic molecules that cannot be metabolized by E. coli, such as isopropyl thiogalactopyranoside (IPTG), have been frequently used to trigger the protein expression during early exponential growth phase. This practice has many drawbacks, including high cost and toxicity of IPTG, complex operating procedure, and non-uniform protein expression pattern (some cells in the population do not express recombinant proteins). A few auto-inducible protein expression systems have been developed recently to overcome some of these limitations, but they required use of an additional plasmid or presence of large (a few kilobases) DNA part to be functional, making plasmid construction to be difficult, especially when multiple genes need to be expressed. In this study, by using RNA sequencing, we identified a short, endogenous promoter (PthrC) that can be auto-induced during early exponential growth phase, and improved its performance by use of native and mutated regulatory elements. We found that the developed mutants of PthrC drove uniform protein expression—close to 100% of cells were fluorescent when green fluorescence protein was used as target protein—and cells carrying them could achieve much higher cell density than those with T7 promoter (PT7), a commonly used inducible promoter. In terms of promoter strength (product protein quantity per cell), the developed promoter mutants can cover a range of strength, from 30 to 150% of maximal strength of PT7. One strong mutant (PthrC3_8) was found to work well at a large range of temperature (22, 30, 37 °C) and in various media, and was also confirmed to cause less stress to host cell than PT7 when they were used to express a toxic protein. We foresee that PthrC3 and its mutants will be useful genetic parts for various applications including metabolic engineering and biocatalysis.
      PubDate: 2018-06-08
      DOI: 10.1007/s00253-018-9141-z
  • Back to the past—forever young: cutting-edge biochemical and
           microbiological tools for cultural heritage conservation
    • Authors: Roberto Mazzoli; Maria Gabriella Giuffrida; Enrica Pessione
      Abstract: Ancient documents and milestones of human history such as manuscripts and textiles are fragile and during aging undergo chemical, physical, and biological deterioration. Among the different causes of damage, also human intervention plays a role since some restoration strategies proved to be transient and/or they generated further damage. Outdoor monuments undergo deterioration since they are exposed to pollution, weathering, microbial attack (giving rise to undesired pigmentation, discoloration or true dissolution, corrosion, and overall decay), as well as man-made damage (i.e., graffiti). This review article reports the best-fitting strategies used to restore wall paintings, outdoor monuments, textiles, and paper documents to their ancient beauty by employing “soft” biobased approaches such as viable bacteria or suitable enzymes.
      PubDate: 2018-06-08
      DOI: 10.1007/s00253-018-9121-3
  • Comparative analysis of fermentation and enzyme expression profiles among
           industrial Saccharomyces cerevisiae strains
    • Authors: Kiyoka Uebayashi; Hiroshi Shimizu; Fumio Matsuda
      Abstract: Industrial diploid strains of Saccharomyces cerevisiae are selected from natural populations and then domesticated by optimizing the preferred properties for producing products such as bread, wine, and sake. In this study, for comparing the fermentation performance of various industrial yeasts, seven diploid strains of S. cerevisiae, namely, BY4947 (laboratory yeast derived from S288C), Kyokai7 and Kyokai9 (sake yeasts), Red Star and NBRC0555 (bread yeasts), and QA23 and EC1118 (wine yeasts), were cultivated in a synthetic medium. The fermentation profiles of the seven yeast strains showed significant differences. The specific ethanol production rates of sake yeasts (Kyokai7 and Kyokai9) and wine strains (QA23 and EC1118) were higher and lower than those of laboratory strains, respectively. Targeted proteome analysis was also conducted to investigate the variation in the expression of metabolism-related enzymes. The expression profiles of central metabolism-related enzymes showed considerable variations among the industrial strains. Upregulation of the TCA cycle in wine strains was observed both in the synthetic and grape-juice media. These results suggested that these variations should be consequences of complex interactions between the domestication process, genetic polymorphism, and environmental factors such as the fermentation conditions.
      PubDate: 2018-06-07
      DOI: 10.1007/s00253-018-9128-9
  • Role of plant phytochemicals and microbial enzymes in biosynthesis of
           metallic nanoparticles
    • Authors: Muhammad Ovais; Ali Talha Khalil; Nazar Ul Islam; Irshad Ahmad; Muhamamd Ayaz; Muthupandian Saravanan; Zabta Khan Shinwari; Sudip Mukherjee
      Abstract: Metal-based nanoparticles have gained tremendous popularity because of their interesting physical, biological, optical, and magnetic properties. These nanoparticles can be synthesized using a variety of different physical, chemical, and biological techniques. The biological means are largely preferred as it provides an environmentally benign, green, and cost-effective route for the biosynthesis of nanoparticles. These bioresources can act as a scaffold, thereby playing the role of reducing as well as capping agents in the biosynthesis of nanoparticles. Medicinal plants tend to have a complex phytochemical constituent such as alcohols, phenols, terpenes, alkaloids, saponins, and proteins, while microbes have key enzymes which can act as reducing as well as stabilizing agent for NP synthesis. However, the mechanism of biosynthesis is still highly debatable. Herein, the present review is directed to give an updated comprehensive overview towards the mechanistic aspects in the biosynthesis of nanoparticles via plants and microbes. Various biosynthetic pathways of secondary metabolites in plants and key enzyme production in microbes have been discussed in detail, along with the underlying mechanisms for biogenic NP synthesis.
      PubDate: 2018-06-07
      DOI: 10.1007/s00253-018-9146-7
  • The discovery and development of microbial bleomycin analogues
    • Authors: Jieqian Kong; Liwei Yi; Yi Xiong; Yong Huang; Dong Yang; Xiaohui Yan; Ben Shen; Yanwen Duan; Xiangcheng Zhu
      Abstract: The bleomycins (BLMs) belong to a subfamily of glycopeptide antibiotics and are clinically applied in combination chemotherapy regimens to treat various malignancies. But the therapeutic applications of BLMs are restricted by the accompanied dose-dependent lung toxicity and potential incidence of lung fibrosis. Many efforts have been devoted to develop novel BLM analogues, for seeking of drug leads with improved antitumor activity and/or reduced lung toxicity. The progresses in the biosynthetic studies of BLMs have greatly expedited the process to achieve such goals. This review highlights the discovery and development of microbial BLM analogues in the past two decades, especially those derived from engineered biosynthesis. Moreover, the summarized structure-activity relationship, which is specifically focusing on the sugar moiety, shall shed new insights into the prospective development of BLM analogues.
      PubDate: 2018-06-06
      DOI: 10.1007/s00253-018-9129-8
  • The impacts of Lachancea thermotolerans yeast strains on winemaking
    • Authors: Santiago Benito
      Abstract: At one time, Saccharomyces spp. yeasts were the only option for use in winemaking due to their unique abilities to metabolize all grape juice sugars to ethanol. However, during the previous decade, several commercial non-Saccharomyces yeast products appeared in the biotechnology market. Some of them have slowly begun to establish new enological resources to solve modern winemaking challenges in the new century. Among these challenges, acidification in the warm-growing regions is of great concern for improving wine quality from those areas, particularly in light of the predictions of serious climate change. This review explores one of the most popular commercialized non-Saccharomyces yeast options in warm viticultural regions, Lachancea thermotolerans, and its influences on wine quality parameters, such as lactic acid, ethanol, glycerol, volatile acidity, volatile profiles, isovaleric acid, mannoproteins, polysaccharides, color, anthocyanins, amino acids, and sensory perception.
      PubDate: 2018-06-06
      DOI: 10.1007/s00253-018-9117-z
  • Comprehensive optimization of the metabolomic methodology for metabolite
           profiling of Corynebacterium glutamicum
    • Authors: Qiongqiong Zhang; Xiaomei Zheng; Yu Wang; Jiandong Yu; Zhidan Zhang; Taiwo Dele-Osibanjo; Ping Zheng; Jibin Sun; Shiru Jia; Yanhe Ma
      Abstract: Metabolomics has been a potential tool for strain improvement through analyzing metabolite changes in the context of different conditions. However, the availability of a universal metabolite profiling analysis is still a big challenge. In this study, we presented an optimized liquid chromatography-tandem mass spectrometry-based metabolomics methodology for Corynebacterium glutamicum, an important industrial workhorse. It was found that quenching the cellular metabolism with 5-fold volume of − 20 °C 40% methanol was highly recommended due to its lower cell damage rate and higher intracellular metabolite recovery rate. For extracting intracellular metabolites, ethanol/water (3:1, v/v) at 100 °C combined with acidic acetonitrile/water (1:1, v/v, with 0.1% formic acid) at − 20 °C achieved the unbiased metabolite profiling of C. glutamicum. The established methodology was then applied to investigate the intracellular metabolite differences between C. glutamicum ATCC 13032 and an mscCG-deleted mutant under biotin limitation condition. It was observed that in the presence of the functional l-glutamate exporter MscCG, biotin limitation led to accumulation of intracellular 2-oxoglutarate but not l-glutamate. Deletion of mscCG severely inhibited l-glutamate excretion and resulted in a dramatical increase of intracellular l-glutamate, which in turn affected the metabolite profile. The optimized metabolomics methodology holds promise for promoting studies on metabolic mechanism of C. glutamicum.
      PubDate: 2018-06-06
      DOI: 10.1007/s00253-018-9095-1
  • Transposon-based identification of a negative regulator for the antibiotic
           hyper-production in Streptomyces
    • Authors: Shuai Luo; Xin-Ai Chen; Xu-Ming Mao; Yong-Quan Li
      Abstract: Production of secondary metabolites in Streptomyces is regulated by a complex regulatory network precisely, elaborately, and hierarchically. One of the main reasons for the low yields of some high-value secondary metabolites is the repressed expression of their biosynthetic gene clusters, supposedly by some gene cluster out-situated negative regulators. Identification of these repressors and removal of the inhibitory effects based on the regulatory mechanisms will be an effective way to improve their yields. For proof of the concept, using an antibiotic daptomycin from Streptomyces roseosporus, we introduced Himar1-based random mutagenesis combined with a reporter-guided screening strategy to identify a transcriptional regulator PhaR, whose loss-of-function deletion led to about 2.68-fold increase of the gene cluster expression and approximately 6.14-fold or 43% increased daptomycin production in the flask fermentation or in the fed-batch fermentation, respectively. Further study showed that PhaR negatively regulates the expression of daptomycin biosynthetic gene cluster by direct binding to its promoter (dptEp). Moreover, phaR expression gradually drops down during fermentation, and PhaR is positively auto-regulated by directly binding to its own promoter, which results in positive feedback regulation to persistently reduce phaR expression. Meanwhile, the declining PhaR protein remove its repressive effects during daptomycin production. All these results support that our strategy would be a powerful method for genetic screening and rational engineering for the yield improvement of antibiotics, and could be potentially used widely in other Streptomyces species.
      PubDate: 2018-06-06
      DOI: 10.1007/s00253-018-9103-5
  • Effects of the histone-like protein HU on cellulose degradation and
           biofilm formation of Cytophaga hutchinsonii
    • Authors: Zhiwei Guan; Ying Wang; Lijuan Gao; Weican Zhang; Xuemei Lu
      Abstract: Cytophaga hutchinsonii, belonging to Bacteroidetes, is speculated to use a novel cell-contact mode to digest cellulose. In this study, we identified a histone-like protein HU, CHU_2750, in C. hutchinsonii, whose transcription could be induced by crystalline but not amorphous cellulose. We constructed a CHU_2750-deleted mutant and expressed CHU_2750 in Escherichia coli to study the gene’s functions. Our results showed that although the deletion of CHU_2750 was not lethal to C. hutchinsonii, the mutant displayed an abnormal filamentous morphology, loose nucleoid, and obvious defects in the degradation of crystalline cellulose and cell motility. Further study indicated that the mutant displayed significantly decreased cell surface and intracellular endoglucanase activities but with β-glucosidase activities similar to the wild-type strain. Analyses by real-time quantitative PCR revealed that the transcription levels of many genes involved in cellulose degradation and/or cell motility were significantly downregulated in the mutant. In addition, we found that CHU_2750 was important for biofilm formation of C. hutchinsonii. The main extracellular components of the biofilm were analyzed, and the results showed that the mutant yielded significantly less exopolysaccharide but more extracellular DNA and protein than the wild-type strain. Collectively, our findings demonstrated that CHU_2750 is important for cellulose degradation, cell motility, and biofilm formation of C. hutchinsonii by modulating transcription of certain related genes, and it is the first identified transcriptional regulator in these processes of C. hutchinsonii. Our study shed more light on the mechanisms of cellulose degradation, cell motility, and biofilm formation by C. hutchinsonii.
      PubDate: 2018-06-06
      DOI: 10.1007/s00253-018-9071-9
  • EcXyl43 β-xylosidase: molecular modeling, activity on natural and
           artificial substrates, and synergism with endoxylanases for lignocellulose
    • Authors: Ornella M. Ontañon; Silvina Ghio; Rubén Marrero Díaz de Villegas; Florencia E. Piccinni; Paola M. Talia; María L. Cerutti; Eleonora Campos
      Abstract: Biomass hydrolysis constitutes a bottleneck for the biotransformation of lignocellulosic residues into bioethanol and high-value products. The efficient deconstruction of polysaccharides to fermentable sugars requires multiple enzymes acting concertedly. GH43 β-xylosidases are among the most interesting enzymes involved in hemicellulose deconstruction into xylose. In this work, the structural and functional properties of β-xylosidase EcXyl43 from Enterobacter sp. were thoroughly characterized. Molecular modeling suggested a 3D structure formed by a conserved N-terminal catalytic domain linked to an ancillary C-terminal domain. Both domains resulted essential for enzymatic activity, and the role of critical residues, from the catalytic and the ancillary modules, was confirmed by mutagenesis. EcXyl43 presented β-xylosidase activity towards natural and artificial substrates while arabinofuranosidase activity was only detected on nitrophenyl α-L-arabinofuranoside (pNPA). It hydrolyzed xylobiose and purified xylooligosaccharides (XOS), up to degree of polymerization 6, with higher activity towards longer XOS. Low levels of activity on commercial xylan were also observed, mainly on the soluble fraction. The addition of EcXyl43 to GH10 and GH11 endoxylanases increased the release of xylose from xylan and pre-treated wheat straw. Additionally, EcXyl43 exhibited high efficiency and thermal stability under its optimal conditions (40 °C, pH 6.5), with a half-life of 58 h. Therefore, this enzyme could be a suitable additive for hemicellulases in long-term hydrolysis reactions. Because of its moderate inhibition by monomeric sugars but its high inhibition by ethanol, EcXyl43 could be particularly more useful in separate hydrolysis and fermentation (SHF) than in simultaneous saccharification and co-fermentation (SSCF) or consolidated bioprocessing (CBP).
      PubDate: 2018-06-06
      DOI: 10.1007/s00253-018-9138-7
  • Decay of sewage-associated bacterial communities in fresh and marine
           environmental waters and sediment
    • Authors: Warish Ahmed; Christopher Staley; Thomas Kaiser; Michael J. Sadowsky; Sonya Kozak; David Beale; Stuart Simpson
      Abstract: Understanding the microbial quality of recreational waters is critical to effectively managing human health risks. In recent years, the development of new molecular methods has provided scientists with alternatives to the use of culture-based fecal indicator methods for investigating sewage contamination in recreational waters. Before these methods can be formalized into guidelines, however, we must investigate their utility, including strengths and weaknesses in different environmental media. In this study, we investigated the decay of sewage-associated bacterial communities in water and sediment from three recreational areas in Southeast Queensland, Australia. Outdoor mesocosms with water and sediment samples from two marine and one freshwater sites were inoculated with untreated sewage and sampled on days 0, 1, 4, 8, 14, 28, and 50. Amplicon sequencing was performed on the DNA extracted from water and sediment samples, and SourceTracker was used to determine the decay of sewage-associated bacterial communities and how they change following a contamination event. No sewage-associated operational taxonomic units (OTUs) were detected in water and sediment samples after day 4; however, the bacterial communities remained changed from their background measures, prior to sewage amendment. Following untreated sewage inoculation, the mesocosm that had the most diverse starting bacterial community recovered to about 60% of its initial community composition, whereas the least diverse bacterial community only recovered to about 30% of its initial community composition. This suggests that a more diverse bacterial community may play an important role in water quality outcomes after sewage contamination events. Further investigation into potential links between bacterial communities and measures of fecal indicators, pathogens, and microbial source tracking (MST) markers is warranted and may provide insight for recreational water decision-makers.
      PubDate: 2018-06-05
      DOI: 10.1007/s00253-018-9112-4
  • Characterization of an atypical, thermostable, organic solvent- and
           acid-tolerant 2 ′ -deoxyribosyltransferase from Chroococcidiopsis
    • Authors: Jon Del Arco; Pedro Alejandro Sánchez-Murcia; José Miguel Mancheño; Federico Gago; Jesús Fernández-Lucas
      Abstract: In our search for thermophilic and acid-tolerant nucleoside 2′-deoxyribosyltransferases (NDTs), we found a good candidate in an enzyme encoded by Chroococcidiopsis thermalis PCC 7203 (CtNDT). Biophysical and biochemical characterization revealed CtNDT as a homotetramer endowed with good activity and stability at both high temperatures (50–100 °C) and a wide range of pH values (from 3 to 7). CtNDT recognizes purine bases and their corresponding 2′-deoxynucleosides but is also proficient using cytosine and 2′-deoxycytidine as substrates. These unusual features preclude the strict classification of CtNDT as either a type I or a type II NDT and further suggest that this simple subdivision may need to be updated in the future. Our findings also hint at a possible link between oligomeric state and NDT’s substrate specificity. Interestingly from a practical perspective, CtNDT displays high activity (80–100%) in the presence of several water-miscible co-solvents in a proportion of up to 20% and was successfully employed in the enzymatic production of several therapeutic nucleosides such as didanosine, vidarabine, and cytarabine.
      PubDate: 2018-06-05
      DOI: 10.1007/s00253-018-9134-y
  • Biotechnological applications of occlusion bodies of Baculoviruses
    • Authors: M. G. López; M. Diez; V. Alfonso; O. Taboga
      Abstract: The ability of Baculoviruses to hyper-express very late genes as polyhedrin, the major component of occlusion bodies (OBs) or polyhedra, has allowed the evolution of a system of great utility for biotechnology. The main function of polyhedra in nature is to protect Baculovirus in the environment. The possibility of incorporating foreign proteins into the crystal by fusing them to polyhedrin (POLH) opened novel potential biotechnological uses. In this review, we summarize different applications of Baculovirus chimeric OBs. Basically, the improvement of protein expression and purification with POLH as a fusion partner; the use of recombinant polyhedra as immunogens and antigens, and the incorporation of proteins into polyhedra to improve Baculoviruses as bioinsecticides. The results obtained in each area and the future trends in these topics are also discussed.
      PubDate: 2018-06-05
      DOI: 10.1007/s00253-018-9130-2
  • Hematite and multi-walled carbon nanotubes stimulate a faster syntrophic
           pathway during methanogenic beet sugar industrial wastewater degradation
    • Authors: John Justo Ambuchi; Zhaohan Zhang; Yue Dong; Linlin Huang; Yujie Feng
      Abstract: The quest to understand and subsequently improve the role played by bacteria and archaea in the degradation of organic matter both in natural and engineered anaerobic ecosystems has intensified the utilization of nanoparticles. Microbial communities are known to syntrophically cooperate during the anaerobic conversion of substrates into methane gas via the direct exchange of electrons. In this study, the role of hematite (Fe2O3—750 mg/L) and multi-walled carbon nanotubes (MWCNTs—1500 mg/L) during the degradation of beet sugar industrial wastewater (BSIW) in a batch experiment was investigated. Hematite and MWCNTs enhanced methane gas generation by 35 and 20%, respectively. Furthermore, microbial syntrophic communities might have exchanged metabolic electrons more directly, with hematite and MWCNTs serving as electron conduits between the homoacetogens and methanogens, thereby establishing a direct interspecies electron transfer (DIET) pathway. Additionally, hematite and MWCNTs enriched the bacteria Firmicutes while Chloroflexi reduced in abundance. Scanning electron microscopy and confocal laser scanning microscopy demonstrated that extracellular polymeric substances had noticeable interactions with both hematite and MWCNTs. Our findings provide vital information for more understanding of the response of microbes to hematite and MWCNTs in a complex natural environment.
      PubDate: 2018-06-04
      DOI: 10.1007/s00253-018-9100-8
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