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I. Andersone L. Auzina A. Vigants O. Mutere P. Zikmanis 《Engineering in Life Science》2004,4(1):56-59
Levansucrase (EC 2.4.1.10.) of Zymomonas mobilis 113S can perform the polymerisation of fructose moiety from raffinose to levan concomitantly with a release of non‐catabolised melibiose into the medium. The kinetic parameters of the levansucrase‐catalysed reaction provide even higher reaction velocities on raffinose as compared to sucrose, particularly at low substrate concentrations. A decreased value in the number of the average molecular mass (Mn = 1693 kDa), an increased intrinsic viscosity (η = 49.47 cm3/g), and a diminished Huggin's constant (K' = 0.67) are intrinsic to the levan synthesis from raffinose, indicating certain structural peculiarities compared to a polysaccharide obtained from sucrose (Mn = 1851 kDa, [η] = 42.47 cm3/g, K' = 1.21). 相似文献
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Laisana Shakirova Mara Grube Marita Gavare Lilija Auzina Peteris Zikmanis 《Journal of industrial microbiology & biotechnology》2013,40(1):85-93
Changes in the cell surface hydrophobicity (CSH) of probiotic bacteria Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 and the survival of these cells were examined in response to varied cultivation conditions and adverse environmental conditions. An inverse linear relationship (P < 0.01) was detected between the CSH of intact L. acidophilus La5 and B. lactis Bb12 and survival of cells subjected to subsequent freezing/thawing, long-term storage or exposure to mineral and bile acids. The observed relationships were supported by significant correlations between the CSH and changes in composition of the cell envelopes (proteins, lipids and carbohydrates) of L. acidophilus La5 and B. lactis Bb12 examined using FT-IR spectroscopy and conventional biochemical analysis methods. The results also suggest that the estimates of hydrophobicity, being a generalized characteristic of cell surfaces, are important parameters to predict the ability of intact probiotic bacteria to endure extreme environments and therefore should be monitored during cultivation. A defined balance of cell components, which can be characterized by the reduced CSH values, apparently helps to ensure the resistance, improved viability and hence the overall probiotic properties of bacteria. 相似文献
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Giedrė Ramanauskaitė Dovilė Žalalytė Vytautas Kašėta Aida Vaitkuvienė Lilija Kalėdienė Genė Biziulevičienė 《Central European Journal of Biology》2014,9(4):367-373
Due to their unique properties, bone marrow-derived Lin? cells can be used to regenerate damaged tissues, including skin. The objective of our study was to determine the influence of the skin tissue-specific microenvironment on mouse Lin? cell proliferation and migration in vitro. Cells were analyzed for the expression of stem/progenitor surface markers by flow cytometry. Proliferation of MACS-purified cells in 3D cultures was investigated by WST-8 assay. Lin? cell migration was evaluated by in vitro scratch assay. The results obtained show that basement membrane matrix is more effective for Lin? cell proliferation in vitro. However, type I collagen matrix better enhances the re-epithelization process, that depends on the cell migratory properties. These studies are important for preparing cells to be used in transplantation. 相似文献
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Stefan Frank Gaurav Ahuja Deniz Bartsch Nicole Russ Wenjie Yao Joseph Chao-Chung Kuo Jens-Peter Derks Vijay Suresh Akhade Yulia Kargapolova Theodore Georgomanolis Jan-Erik Messling Marie Gramm Lilija Brant Rizwan Rehimi Natalia Emilse Vargas Alina Kuroczik Tsun-Po Yang Raja Ghazanfar Ali Sahito Leo Kurian 《Cell Stem Cell》2019,24(2):318-327.e8
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Increasing numbers of human cowpox virus infections that are being observed and that particularly affect young non-vaccinated persons have renewed interest in this zoonotic disease. Usually causing a self-limiting local infection, human cowpox can in fact be fatal for immunocompromised individuals. Conventional smallpox vaccination presumably protects an individual from infections with other Orthopoxviruses, including cowpox virus. However, available live vaccines are causing severe adverse reactions especially in individuals with impaired immunity. Because of a decrease in protective immunity against Orthopoxviruses and a coincident increase in the proportion of immunodeficient individuals in today's population, safer vaccines need to be developed. Recombinant subunit vaccines containing cross-reactive antigens are promising candidates, which avoid the application of infectious virus. However, subunit vaccines should contain carefully selected antigens to confer a solid cross-protection against different Orthopoxvirus species. Little is known about the cross-reactivity of antibodies elicited to cowpox virus proteins. Here, we first identified 21 immunogenic proteins of cowpox and vaccinia virus by serological screenings of genomic Orthopoxvirus expression libraries. Screenings were performed using sera from vaccinated humans and animals as well as clinical sera from patients and animals with a naturally acquired cowpox virus infection. We further analyzed the cross-reactivity of the identified immunogenic proteins. Out of 21 identified proteins 16 were found to be cross-reactive between cowpox and vaccinia virus. The presented findings provide important indications for the design of new-generation recombinant subunit vaccines. 相似文献
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Pēteris Zikmanis Ramona Krūće Lilija Auziņa Vasily Bankovsky 《Archives of microbiology》1992,158(3):203-207
The plant growth substance N6-(2-isopentenyl) adenine (i6Ade) significantly inhibits the rates of ethanol oxidation and acetaldehyde reduction in vitro by cell-free extracts of Zymomonas mobilis and of an Escherichia coli recombinant strain, containing the Z. mobilis adhB gene. The two-substrate kinetics of ethanol oxidation (forward) is affected by increasing values of dissociation constants for coenzyme and coenzyme —enzyme complexes in the presence of i6Ade, whereas the reaction maximum velocity (V
m) remains unchanged and reflects the competitive type of inhibition. Changes of the kinetic constants of acetaldehyde reduction (back) are similar, except the increasing value of V
m and correspond to the CIS (competitive inhibition and stimulation) type of inhibition. The estimated values of inhibition constants of the forward and back reactions are 0.39 ± 0.05 mM and 0.19 ± 0.06 mM, respectively. 相似文献
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The presence of cytoplasmic and membrane‐bound adenylate kinase (EC 2.7.4.3) as well as inorganic pyrophosphatase (EC 3.6.1.1) was detected in Zymomonas mobilis ATCC 29191. An increase in the molar growth yield (YX/S) of Z. mobilis under aerobic growth conditions appeared to be in proportion to a reduction of membrane‐bound adenylate kinase (mAK) and ATPase activities and to an increase in cytoplasmic adenylate kinase (AK) activity. Significant (1 — P < 0.01) multiple regressions were observed between the values of YX/S (dependent variable), ATPase and AK or AK and mAK as independent variables, suggesting that a combined operation of these phosphohydrolases and phosphotransferases would be responsible for the biomass yield in Z. mobilis. 相似文献
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P. B. Zikmanis S. I. Auzane L. P. Auzina M. V. Margevicha M. J. Beker 《Applied microbiology and biotechnology》1985,22(4):265-267
Summary An investigation was made of changes in ergosterol content of the yeast Saccharomyces cerevisiae upon drying and subsequent rehydration. It was established that drying increases, but rehydration diminishes ergosterol content in yeasts. A statistically reliable multiple correlation was established between the resistance of population to drying, decrease of ergosterol content and a diminishing degree of fatty acid unsaturation during dehydration of dry yeasts. 相似文献