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1.
The chemotactic behaviour of Campylobacter strains was determined in the presence of different amino acids at two temperatures (37 °C and 42 °C). Two strains of catalase positive (Campylobacter jejuni) and negative (Campylobacter sputurum) Campylobacter were isolated from river water in Tonekabon, Iran and identified by phenotyping and 16srRNA Gene sequencing methods. Chemotactic responses of the isolates were assessed toward a variety of amino acids viz., L-cystine, L-asparagine, L-histidine, L-aspartic acid, L-serine, L-phenylalanine, L-leucine and L-tryptophan by disc and capillary methods at two temperatures: 37 °C and 42 °C. C. jejuni showed positive chemotactic response towards L-cystine,L-tryptophan, L-phenylalanine, - L-leucine, L-asparagine and L-Serine at both, 37 °C and 42 °C however, it was greater at 37 °C. C. sputurum showed negative or weak response towards all of the amino acids. In addition, C. jejuni illustrated strong chemotactic response to L-asparagine follow by L-serine and weak chemotaxis response to L-phenylalanine and L-cysteine at 37 °C. Overall, C. jejuni showed relatively strong chemotactic response to some amino acids, likewise it was greater at 37 °C. Hence, the human body temperature (37 °C) in compared to avian body temperature (42 °C) probably promotes chemotactic response of C. jejuni, which it might be a reason for causing disease in human being compared to avian. 相似文献
2.
Jin Seok Seo Yeon Jung Kim Jong Moon Cho Eric Baek Gyun Min Lee 《Applied microbiology and biotechnology》2013,97(12):5283-5291
The human host cell line, F2N78, is a new somatic hybrid cell line designed for therapeutic antibody production. To verify its potential as a human host cell line, recombinant F2N78 cells that produce antibody against rabies virus (rF2N78) were cultivated at different culture pH (6.8, 7.0, 7.2, 7.4, and 7.6) and temperatures (33.0 °C and 37.0 °C). Regardless of the culture temperature, the highest specific growth rate was obtained at a pH of 7.0–7.4. Lowering the culture temperature from 37.0 °C to 33.0 °C suppressed cell growth while allowing maintenance of high cell viability for a longer period. However, it did not enhance antibody production because specific antibody productivity did not increase at 33.0 °C. The highest maximum antibody concentration was obtained at 37.0 °C and pH 6.8. The N-linked glycosylation of the antibody was affected by the culture pH rather than the temperature. Nevertheless, G1F was dominant and G2F occupied a larger portion than G0F in all culture conditions. Compared to the same antibody produced from recombinant CHO cells, the antibody produced from rF2N78 cells has more galactose capping and was more similar to human plasma IgG. Taken together, the results obtained here demonstrate the potential of F2N78 as an alternative human host cell line for therapeutic antibody production. 相似文献
3.
Lakshmi Yella Marjorie S. Morgan Larry G. Arlian 《Experimental & applied acarology》2013,60(1):117-126
House dust mites are cultured to obtain mite allergen material to produce allergen extracts (vaccines) for diagnostic tests, immunotherapy, and research purposes. Research laboratories and manufacturers have their own culturing protocols to grow these mites and these may vary between manufacturers and between research laboratories. The temperature at which mites are cultured may influence the allergen composition, allergen ratio of Der 1: Der 2 and endotoxin levels in the extracts produced from these cultured mites. In order to produce standardized and uniform extracts, across the industry and in various research laboratories, the influence of culture conditions must be understood. Here we determined how temperature affects mite population growth rates, dynamics of allergen production, Der f 1: Der f 2 ratio and endotoxin levels in extracts made from Dermatophagoides farinae mites cultured at 20 and 25 °C. We found that Der f 1 and Der f 2 accumulated exponentially in the cultures with Der f 1 accumulating faster than Der f 2. When the live mite populations peaked, the ratios for Der f 1: Der f 2 were 4.1 and 4.7 for cultures reared at 20 and 25 °C, respectively. Most of the Der f 1 and Der f 2 allergen in whole cultures is not in mite bodies and is lost when the mite material is washed. Thus, if the ratio of Der f 1 and Der f 2 is an important consideration for commercial and research extracts, then the temperature at which the mites are cultured and the collection procedure are important considerations. 相似文献
4.
Talita Rafaele D’Agostini Mantovani Henrique Susumu Tanaka Suzana Harue Umeo Lienine Luiz Zaghi Junior Juliana Silveira do Valle Luzia Doretto Paccola-Meirelles Giani Andrea Linde Nelson Barros Colauto 《Indian journal of microbiology》2012,52(3):484-488
Alternative substrates for cryopreservation at −20 °C have been little explored for basidiomycetes and could bring new possibilities of lower cost cryopreservation. Nevertheless, freezing temperatures between −15 and −60 °C are very challenging because they frequently result in cryoinjuries. The objective of this study was to evaluate substrates associated to cryoprotective agents for Pleurotus ostreatus cryopreservation at −20 or −70 °C in order to develop alternative techniques for basidiomycete cryopreservation. P. ostreatus was grown on potato dextrose agar or whole grains of oat, wheat, rice or millet and transferred to cryovials with cryoprotective solution with 1 % dimethyl sulfoxide, 5 % glycerol, 10 % saccharose, 4 % glucose, 6 % polyethylene glycol-6000 or 5 % malt extract. The mycelium in the cryovials were cryopreserved at −20 or −70 °C and recovered for evaluation of the mycelial growth viability after 1 and 3 years. Both substrates and cryoprotectants affect the viability of the mycelial growth cryopreserved at −20 or −70 °C; wheat grains combined with cryoprotectants such as saccharose or glucose are effective for keeping mycelium viable after cryopreservation at −20 °C for 1 or 3 years; for cryopreservation at −70 °C after 1 or 3 years, any substrate combined with any cryoprotectant is effective for preserving the mycelium viable, except for millet grains with polyethylene glycol after 3 years; semi-permeable cryoprotective agents such as saccharose and glucose are the most effective for cryopreservation at −20 or −70 °C for at least 3 years. 相似文献
5.
Mariko Nakagawa Aya Tabara Yuki Ushijima Kotaro Matsunaga 《Bioscience, biotechnology, and biochemistry》2016,80(5):983-990
Rice flour was stored at 15 °C/9 months, at 35 °C/14 days, or dry-heated at 120 °C/20 min. The breadmaking properties baked with this rice flour/fresh gluten flour deteriorated. In addition, the rice flour was mixed with oil in water vigorously, and oil-binding ability was measured. Every rice flour subjected to storage or dry-heated at 120 °C showed higher hydrophobicity, owing to changes in proteins. Then, proteins in the stored rice flour were excluded with NaOH solution, and bread baked with the deproteinized rice flour showed the same breadmaking properties as unstored rice flour/fresh gluten flour. The viscoelasticity of wheat glutenin fraction decreased after the addition of dry-heated rice flour in a mixograph profile. DDD staining increased Lab in color meter, which suggested an increase in SH groups in rice protein. The increase in SH groups caused a reduction in wheat gluten protein resulting in a deterioration of rice bread quality. 相似文献
6.
André Overmeyer Sandra Schrader-Lippelt Volker Kasche Gerd Brunner 《Biotechnology letters》1999,21(1):65-69
The reaction rate and selectivity of the enzymatic kinetic resolution of ibuprofen and 1-phenylethanol with supercritical CO2 as solvent were studied in a batch reactor from 40 °C to 160 °C. The commercial enzyme, Novozym 435, remained partly active for at least 14 h up to 140 °C at 15 MPa. The maximum reaction rate for the esterification of 1-phenylethanol and ibuprofen was at about 90 °C. The enantiomeric excess for 1-phenylethanol exceeds 99% and was temperature independent. Selectivity for ibuprofen esterification reached a lower enantiomeric excess of 61% caused by equilibrium adjustment. The results show that with supercritical CO2 as reaction medium enzymes remain active above 100 °C. 相似文献
7.
Lucie Vyletova La’Verne P. Rennalls Kirstin J. L. Wood Valerie M. Good 《Cytotechnology》2016,68(2):303-311
Standard tissue culture methods advise freezing cells in small aliquots (≤1 × 107 cells in 1 mL), and storing in liquid nitrogen. This is inconvenient for laboratories culturing large quantities of insect cells for recombinant baculovirus expression, owing to the length of time taken to produce large scale cultures from small aliquots of cells. Liquid nitrogen storage requires use of specialized cryovials, personal protective equipment and oxygen monitoring systems. This paper describes the long-term, large scale cryopreservation of 8 × 108 insect cells at −80 °C, using standard 50 mL conical tubes to contain a 40 mL cell suspension. Sf9, Sf21 and High 5 cells were recovered with a viability > 90 % after storage for one year under these conditions, which compared favorably with the viability of cells stored in liquid nitrogen for the same length of time. Addition of green fluorescent protein encoding baculovirus demonstrated that cells were “expression ready” immediately post thaw. Our method enables large scale cultures to be recovered rapidly from stocks cryopreserved at −80 °C, thus avoiding the inconvenience, hazards and expense associated with liquid nitrogen.
Electronic supplementary material
The online version of this article (doi:10.1007/s10616-014-9781-5) contains supplementary material, which is available to authorized users. 相似文献8.
Seán Gerrity Eoghan Clifford Colm Kennelly Gavin Collins 《Journal of industrial microbiology & biotechnology》2016,43(5):651-661
The objective of this study was to demonstrate the feasibility of novel, Horizontal Flow Biofilm Reactor (HFBR) technology for the treatment of ammonia (NH3)-contaminated airstreams. Three laboratory-scale HFBRs were used for remediation of an NH3-containing airstream at 10 °C during a 90-d trial to test the efficacy of low-temperature treatment. Average ammonia removal efficiencies of 99.7 % were achieved at maximum loading rates of 4.8 g NH3 m3 h?1. Biological nitrification of ammonia to nitrite (NO2 ?) and nitrate (NO3 ?) was mediated by nitrifying bacterial and archaeal biofilm populations. Ammonia-oxidising bacteria (AOB) were significantly more abundant than ammonia-oxidising archaea (AOA) vertically at each of seven sampling zones along the vertical HFBRs. Nitrosomonas and Nitrosospira, were the two most dominant bacterial genera detected in the HFBRs, while an uncultured archaeal clone dominated the AOA community. The bacterial community composition across the three HFBRs was highly conserved, although variations occurred between HFBR zones and were driven by physicochemical variables. The study demonstrates the feasibility of HFBRs for the treatment of ammonia-contaminated airstreams at low temperatures; identifies key nitrifying microorganisms driving the removal process; and provides insights for process optimisation and control. The findings are significant for industrial applications of gas oxidation technology in temperate climates. 相似文献
9.
Gholam Reza Dashti Zohre Nateghian Farhad Golshan Iranpour 《Cell and tissue banking》2018,19(4):653-658
Sperm motility is the result of transverse movements that exist along its tail. It plays an important role in male fertility. The aim of this study was to evaluate the influence of keeping washed normozoospermic semen samples at 4–6 and 25 °C on the motility of spermatozoa. 26 semen samples of normozoospermic were washed twice in modified Ham’s F10 medium. Then, thirteen of the semen samples were kept in refrigerator (4–6 °C) and the remaining samples were stored in incubator (25 °C) for 12 days. On the 0 (immediately after sampling as control group), 1st, 2nd, 5th, 7th and the 12th days, the percentage of fast progressive (grade a), slow progressive (grade b), non-progressive (grade c) and immotile (grade d) sperm cells were calculated for each temperature. The data obtained from this study showed that the percentages of a, b and c grades of motile spermatozoa were significantly decreased (p?<?0.001) during 12 days at the both temperatures but reduction of these percentages has a gentle slope at 4–6 °C. There was no motile sperm after 12 days of storage. This study suggests that motile spermatozoa could be retrieved up to 7 days after the storage of washed normozoospermic men semen samples at 4–6 and 25 °C. Also, there were no motile sperm cells 12 days after sampling. 相似文献
10.
Dondero F Rossi T Delfino M Imbrogno N Cannistrà S Mazzilli F 《Cell and tissue banking》2006,7(1):61-64
The aim of our study was to evaluate the bio-kinetic characteristics of human semen refrigerated for different periods and
to compare the effects of refrigeration at +4 °C against cryopreservation of human sperm at −196 °C. Semen was obtained from
30 male partners of infertile couples (infertile subjects) with the following semen profile: sperm count ≥10 × 106/ml; progressive motility ≥20%; atypical forms <70% and white blood cells <1.0 × 106/ml. Fifteen normospermic subjects were also selected as controls (control subjects). The following tests were carried out
on basal, refrigerated and cryopreserved sperm: a) sperm kinetic properties (by Superimposed Image Analysis System); b) the
Hypoosmotic Viability Test (HVT) (combined Hypoosmotic Swelling and Viability Test). The results of the study showed that
the percentage recovery of kinetic properties and of HVT were optimum for up to 48 h. After refrigeration for 72 h, a drastic
decrease in straight motility recovery was observed. No significant differences were observed between cryopreservation and
refrigeration at +4 °C for 48 h for motility or HVT recoveries in samples from control subjects. However, in infertile subjects,
a significant decrease in straight progressive motility and HVT recoveries was observed in cryopreserved samples compared
to those refrigerated for 48 h. Neither refrigeration nor cryopreservation led to the growth of pathogenic bacteria in any
of the cases studied. Based on the above results, refrigeration could represent a useful alternative to the cryopreservation
method. 相似文献
11.
Summary Sperm whale apomyoglobin was expressed to high levels on minimal media and isotopically labeled with 13C and 15N nuclei. The isotopically labeled apoprotein was purified to homogeneity in a single step by reversed-phase chromatography and reconstituted with hemin and carbon monoxide gas for NMR analysis. Sequence-specific backbone 1HN, 15N and 13C as well as side-chain 13C resonance assignments have been made for over 90% of the amino acids in the carbon monoxide complex of the protein. Resonance assignments were made by analysis of a series of 3D triple resonance spectra measured on the uniformly labeled sample. These assignments will provide the basis for analyzing the effects of point site mutations on the structure, stability and dynamics of the protein in solution. 相似文献
12.
Forces that are able to transport Na+ and K+ into two compartments were investigated. A modified Nernst-Planck equation for coupled flows of electric current, water, and ions was integrated. The result shows that if alkali ions in the ion channel of the cell membrane are separated by their electric-current-induced inward flows against an electro-osmotic outward flow of water, the logarithms of the stationary cell/medium distributions of these ions should be proportional to the inverse of their diffusion mobilities. The relationship was tested in human erythrocytes. From inward and outward movements of tracer alkali ions, calculations were made to obtain their stationary distributions at infinite time. The cell/medium distributions determined in this way at 38 degrees C are Li+ = 0.59, 22Na+ = 0.044, 42K+ = 10.0, 86Rb+ = 11.9, and 137Cs+ = 3.07. The entry rates of ions into the cell at 0 degrees C are understood to represent their diffusion mobilities in the pump channel. The entry rates are Li+ = 1.44, 2Na+ = 1, 42K+ = 2.22, 86Rb+ = 2.39, and 137Cs+ = 1.72 relative to that of 22Na+. There is an expected negative correlation between the logarithms of the stationary cell/ medium distributions at 38 degrees C and the inverse of the entry rates into the cell at 0 degrees C for the five ions. It is suggested that the proposed physical forces cause the separation of alkali ions in the channel of Na,K-ATPase. 相似文献
13.
14.
Phosphoenolpyruvate carboxylase (PEPCase; EC 4.1.1.31) from Flaveria trinervia Mohr (C4), F. floridana Johnston (C3–C4), and F. cronquistii Powell (C3) leaves were compared by electrotransfer blotting/enzyme-linked immunoassay (Western-blot analysis), mobility of the native enzyme in polyacrylamide gels and in isoelectric focusing (IEF) gels, peptide mapping, and in-vitro translation of RNA isolated from each plant. The PEPCases from the C3 and C3–C4 plants were very similar to each other in terms of electrophoretic mobilities on gels and isoenzyme patterns on IEF gels, and identical in peptide mapping. Quantitative differences were noted, however, in that the C3–C4 intermediate plant contained more PEPCase overall and that the relative activity of individual isoenzymes shifted between the C3 and C3–C4 intermediate PEPCases. The PEPCase from the C4 plant had a different isoenzyme pattern, a different peptide map, and was far more abundant than the other two enzymes. Western blot analysis demonstrated the cross-reactivity of PEPCases from all three Flaveria species with antibody raised against maize PEPCase. The results provide evidence, at the molecular level, that supports the view of C3–C4 intermediate species as C3-like plants with some C4-like photosynthetic characteristics, but there are differences from the C3 plant in the quantity and properties of the PEPCase from the C3–C4 intermediate plant.Abbreviations IEF
isoelectric focusing
- kDa
kilodalton
- PEPCase
phosphoenolpyruvate carboxylase
- Rubisco
Ribulose-1,5-bisphosphate carboxylase/oxygenase 相似文献
15.
The in-situ inter- and intracellular localization patterns of phosphoenolpyruvate (PEP) and ribulose 1,5-bisphosphate (RuBP) carboxylases in green leaves of severalPanicum species were investigated using an indirect immunofluorescence technique. Four species were examined and compared:P. miliaceum (C4),P. bisulcatum (C3), andP. decipiens andP. milioides (C3–C4 intermediates which have Kranz-like leaf anatomy and reduced photorespiration). In the C4
Panicum, PEP carboxylase was located in the cytosol of the mesophyll cells and RuBP carboxylase was restricted to the bundle-sheath chloroplasts. In contrast, in the C3
Panicum species, PEP carboxylase was found throughout the leaf chlorenchyma, in both the cytosol and chloroplasts, and RuBP carboxylase was located in the chloroplasts. For the C3–C4 intermediate plants, the patterns depended on the species examined. ForP. decipiens, the in-situ localization of both carboxylases was similar to that described forP. bisulcatum and other C3 plants. However, inP. milioides, PEP carboxylase was found exclusively in the cytosol of the mesophyll cells, as inP. miliaceum and other C4 species, whereas RuBP carboxylase was distributed in both the mesophyll and bundle-sheath chloroplasts.Abbreviations PEP
phosphoenolpyruvate
- RuBP
ribulose 1,5-bisphosphate 相似文献
16.
This paper describes a method for the temporary storage of cultured cells. Cells from recently completed cell monolayers were trypsinized and then centrifuged. After centrifugation, the supernatant and pellet were kept at 4 °C for one week. After storage, the supernatant was discarded, the cells were resuspended and used for seeding new flasks and for titration of virus. The cells not only remained viable, but also rapidly formed new monolayers and allowed immediate infection and growth of viruses. We conclude that this method can be a helpful asset to cell culture experiments. 相似文献
17.
Detailed cervical spine models are necessary to better understand cervical spine response to loading, improve our understanding of injury mechanisms, and specifically for predicting occupant response and injury in auto crash scenarios. The focus of this study was to develop a C4–C5 finite element model with accurate representations of each tissue within the segment. This model incorporates more than double the number of elements of existing models, required for accurate prediction of response. The most advanced material data available were then incorporated using appropriate nonlinear constitutive models to provide accurate predictions of response at physiological levels of loading. This tissue-scale segment model was validated against a wide variety of experimental data including different modes of loading (axial rotation, flexion, extension, lateral bending, and translation), and different load levels. In general, the predicted response of the model was within the single standard deviation response corridors for both low and high load levels. Importantly, this model demonstrates that appropriate refinement of the finite element mesh, representation at the tissue level, and sufficiently detailed material properties and constitutive models provide excellent response predictions without calibration of the model to experimental data. Load sharing between the disc, ligaments, and facet joints was investigated for various modes of loading, and the dominant load-bearing structure was found to correlate with typical anatomical injury sites for these modes of loading. The C4–C5 model forms the basis for the development of a full cervical spine model. Future studies will focus on tissue-level injury prediction and dynamic response. 相似文献
18.
Weisemann R Rüterjans H Schwalbe H Schleucher J Bermel W Griesinger C 《Journal of biomolecular NMR》1994,4(2):231-240
Summary Sensitive three-dimensional NMR experiments, based on the E.COSY principle, are presented for the measurement of the 3J(HN,H) and 3J(HN,C) coupling constants in uniformly 13C- and 15N-labeled proteins. They employ gradient coherence selection in combination with the sensitivity enhancement method in HSQC-type spectra (Cavanagh et al., 1991; Palmer et al., 1991). In most cases, the two measured coupling constants unambiguously define the -angle for protein structure determination. The method is applied to uniformly 13C, 15N-labeled ribonuclease T1. 相似文献
19.
Vallero MV Lettinga G Lens PN 《Journal of industrial microbiology & biotechnology》2003,30(6):375-382
A laboratory-scale upflow anaerobic sludge bed (UASB) reactor was operated during 273 days at increasing NaCl concentrations (0.5–12.5 g NaCl l–1) to assess whether the stepwise addition of the salt NaCl results in the acclimation of that sludge. The 6.5-l thermophilic (55 °C), sulfidogenic [a chemical oxygen demand (COD) to SO42– ratio of 0.5] UASB reactor operated at an organic loading rate of 5 g COD l–1 day–1, a hydraulic retention time of 10 h and was fed with methanol as the sole electron donor. The results show that the adaptation of the thermophilic, sulfidogenic methanol-degrading biomass to a high osmolarity environment is unlikely to occur. Sulfide was the main mineralization product from methanol degradation, regardless of the NaCl concentration added to the influent. However, sulfide production in the reactor steadily decreased after the addition of 7.5 g NaCl l–1, whereas acetate production was stimulated at that influent NaCl concentration. Batch tests performed with sludge harvested from the UASB reactor when operating at different influent salinities confirmed that acetate is the main metabolic product at NaCl concentrations higher than 12.5 g l–1. The apparent order of NaCl toxicity towards the different trophic groups was found to be: sulfate-reducing bacteria > methane-producing archaea > acetogenic bacteria. 相似文献
20.
In this study biodegradation of hydrocarbons in thin oil films was investigated in seawater at low temperatures, 0 and 5 °C.
Heterotrophic (HM) or oil-degrading (ODM) microorganisms enriched at the two temperatures showed 16S rRNA sequence similarities
to several bacteria of Arctic or Antarctic origin. Biodegradation experiments were conducted with a crude mineral oil immobilized
as thin films on hydrophobic Fluortex adsorbents in nutrient-enriched or sterile seawater. Chemical and respirometric analysis
of hydrocarbon depletion showed that naphthalene and other small aromatic hydrocarbons (HCs) were primarily biodegraded after
dissolution to the water phase, while biodegradation of larger polyaromatic hydrocarbons (PAH) and C10–C36 n-alkanes, including n-hexadecane, was associated primarily with the oil films. Biodegradation of PAH and n-alkanes was significant at both 0 and 5°C, but was decreased for several compounds at the lower temperature. n-Hexadecane biodegradation at the two temperatures was comparable at the end of the experiments, but was delayed at 0°C. Investigations
of bacterial communities in seawater and on adsorbents by PCR amplification of 16S rRNA gene fragments and DGGE analysis indicated
that predominant bacteria in the seawater gradually adhered to the oil-coated adsorbents during biodegradation at both temperatures.
Sequence analysis of most DGGE bands aligned to members of the phyla Proteobacteria (Gammaproteobacteria) or Bacteroidetes. Most sequences from experiments at 0°C revealed affiliations to members of Arctic or Antarctic consortia, while no such
homology was detected for sequences from degradation experiment run at 5°C. In conclusion, marine microbial communities from
cold seawater have potentials for oil film HC degradation at temperatures ≤5°C, and psychrotrophic or psychrophilic bacteria
may play an important role during oil HC biodegradation in seawater close to freezing point. 相似文献