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Optimal Growth Temperature (optimal + growth_temperature)
Selected AbstractsEstablishment and characterization of two new cell lines derived from flounder, Paralichthys olivaceus (Temminck & Schlegel)JOURNAL OF FISH DISEASES, Issue 11-12 2003M S Kang Abstract Two new cell cultures from flounder, Paralichthys olivaceus (Temminck & Schlegel), flounder fin (FFN) cells from fin tissue and flounder spleen (FSP) cells from spleen tissue, were established and characterized. The cells multiplied well in Eagle's minimum essential medium, supplemented with 10% foetal bovine serum, and have been subcultured more than 100 times, becoming continuous cell lines. Modal diploid chromosome number of FFN and FSP cells was 64 and 62, respectively. Polymerase chain reaction products were obtained from FFN and FSP cells with primer sets of microsatellite markers of flounder. Optimal growth temperature was 20 °C and consisted of epithelioid cells. FFN and FSP cells showed cytopathic effects after inoculation of infectious pancreatic necrosis virus, marine birnavirus, chum salmon virus, infectious haematopoietic necrosis virus, spring viraemia of carp virus and hirame rhabdovirus. Thus these new cell lines may be useful for studying a wide range of fish viruses. [source] A novel thermostable hemoglobin from the actinobacterium Thermobifida fuscaFEBS JOURNAL, Issue 16 2005Alessandra Bonamore The gene coding for a hemoglobin-like protein (Tf-trHb) has been identified in the thermophilic actinobacterium Thermobifida fusca and cloned in Escherichia coli for overexpression. The crystal structure of the ferric, acetate-bound derivative, was obtained at 2.48 Å resolution. The three-dimensional structure of Tf-trHb is similar to structures reported for the truncated hemoglobins from Mycobacterium tuberculosis and Bacillus subtilis in its central domain. The complete lack of diffraction patterns relative to the N- and C-terminal segments indicates that these are unstructured polypeptides chains, consistent with their facile cleavage in solution. The absence of internal cavities and the presence of two water molecules between the bound acetate ion and the protein surface suggest that the mode of ligand entry is similar to that of typical hemoglobins. The protein is characterized by higher thermostability than the similar mesophilic truncated hemoglobin from B. subtilis, as demonstrated by far-UV CD melting experiments on the cyano-met derivatives. The ligand-binding properties of Tf-trHb, analyzed in stopped flow experiments, demonstrate that Tf-trHb is capable of efficient O2 binding and release between 55 and 60 °C, the optimal growth temperature for Thermobifida fusca. [source] Phylogeny of cyclic nitramine-degrading psychrophilic bacteria in marine sediment and their potential role in the natural attenuation of explosivesFEMS MICROBIOLOGY ECOLOGY, Issue 3 2004Jian-Shen Zhao Abstract Previously we reported on in situ mineralization of cyclic nitramine explosives including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in marine sediment from Halifax Harbour. In the present study, we isolated several novel psychrophilic bacteria from the sediment with optimal growth temperature at 10 or 15 °C. Phylogenetic analysis of their 16S rRNA genes identified the isolates as members of the gamma and delta subdivisions of Proteobacteria, Fusobacteria and Clostridiales. The isolates mineralized 3.7,45.2% of RDX (92 ,M) in 82 days of incubation at 10 °C under oxygen-limited or anaerobic conditions with the gamma subdivision isolates demonstrating the highest mineralization (45.2% of total C). Removal of RDX by all isolates was accompanied by the formation of all three nitroso derivatives, with the mono nitroso derivative (MNX) being the major one. Isolates of the delta proteobacteria and Fusobacteria removed HMX with concurrent formation of the mononitroso derivative (NO-HMX). Using resting cells of isolates of the gamma subdivision, methylenedinitramine (MEDINA) and 4-nitro-2,4-diazabutanal (NDAB) were detected, suggesting ring-cleavage following denitration of either RDX and/or its initially reduced product, MNX. These results clearly demonstrate that psychrophilic bacteria capable of degrading cyclic nitramines are present in the marine sediment, and might contribute to the in situ biodegradation and natural attenuation of the chemicals. [source] A combined stress response analysis of Spirulina platensis in terms of global differentially expressed proteins, and mRNA levels and stability of fatty acid biosynthesis genesFEMS MICROBIOLOGY LETTERS, Issue 2 2008Wattana Jeamton Abstract Changes in gene expression play a critical role in enhancing the ability of cyanobacteria to survive under cold conditions. In the present study, Spirulina platensis cultures were grown at the optimal growth temperature, in the light, before being transferred to dark conditions at 22 °C. Two dimensional-differential gel electrophoresis was then performed to separate differentially expressed proteins that were subsequently identified by MS. Among all differentiated proteins identified, a protein involved in fatty acid biosynthesis, (3R)-hydroxymyristoyl-[acyl-carrier-protein]-dehydratase encoded by fabZ, was the most up-regulated protein. However, the fatty-acid desaturation proteins were not significantly differentiated. This raised the question of how the unsaturated fatty acid, especially ,-linolenic acid, content in the cells in the cold,dark shift remained stable compared with that of the cold shift. Thus, a study at the transcriptional level of these desaturase genes, desC, desA and desD, and also of the fabZ gene was conducted. The results indicated that in the dark, where energy is limited, mRNA stability was enhanced by exposure to low temperatures. The data demonstrate that when the cells encounter cold stress with energy limitation, they can maintain their homeoviscous adaptation ability via mRNA stability. [source] Effects of temperature and pH on growth and photosynthesis of the thermophilic cyanobacterium Synechococcus lividus as measured by pulse-amplitude modulated fluorometryPHYCOLOGICAL RESEARCH, Issue 4 2006Chung-Ching Liao SUMMARY In this study, the effects of five different temperatures and pH conditions on growth and photosynthetic performance of Synechococcus lividus Copeland from Taiwan were monitored in the field and the laboratory by using an underwater pulse-amplitude modulated (Diving-PAM) fluorometer. In the field, the optimal growth temperature of S. lividus was found to be 57°C. Such a finding was congruent with the growth rate in the laboratory culture, in which the optimal growth temperatures ranged from 45 to 60°C. In photosynthetic performance, the light-saturated maximum relative electron transport rate (ETRmax) and the light-limited slope (,ETR) exhibited highest values at 50°C. At five different pH conditions, higher ETRmax and ,ETR were observed from pH 7 to 9. In addition, regression analysis demonstrated a significant positive relationship between the growth rate and the ETRmax values (R2 = 0.9527), indicating that the growth of S. lividus was largely restricted to its photosynthetic performance. In conclusion, the photosynthetic performance and growth of the thermophilic cyanobacterium S. lividus were sensitive to fluctuations in temperature but not in pH. The present investigation offers a better understanding of the photosynthetic physiology. [source] Morphological, Small Subunit rRNA, and Physiological Characterization of Trimyema minutum (Kahl, 1931), an Anaerobic Ciliate from Submarine Hydrothermal Vents Growing from 28°C to 52°CTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2002MANUELA BAUMGARTNER ABSTRACT. A thermophilic strain of Trimyema minutum was isolated from the hydrothermally heated sea floor at Vulcano Island (Italy) and cultivated monoxenically on Marinobaaer sp. and Methanococcus thermolithotrophicus. It can be propagated strictly an aerobically and is sensitive to oxygen: if exposed to air at 48°C all cells die within 60 min. It grows from 0.45,7.2% (w/v) salt and at pH 6.0,8.0. The isolate is the most extreme thermophilic ciliate which ever has been cultivated, exhibiting an optimal growth temperature of 48°C (doubling time 6 h). Growth occurs between 28°C and 52°C. Trimyema minutum is redescribed using live observation and silver impregnation. Its morphology and the small subunit ribosomal RNA sequence is distinctly different from that of T. compressum, but morphology is highly similar to that of T. shoalsiaNerad et al. 1995, which is thus probably a junior synonym of T. minutum. To stabilize the bewildering species taxonomy in Trimyema. we suggest to recognize our population as a neotype of T. minutum. [source] Biological and technical evaluation of the potential of marine and anadromous fish species for cold-water maricultureAQUACULTURE RESEARCH, Issue 2 2002N R Le François Abstract Concern about the overexploitation of wild aquatic resources, the slow recovery of the groundfish fisheries and the need to encourage the diversification of the mariculture industry of the province of Quebec (Canada) all provided strong incentive to explore the potential of a wide selection of marine and anadromous fish species for cold-water mariculture. Starting from a list of over 45 indigenous fish species of potential commercial interest, a biotechnical review was initiated. Technical sheets for each species were produced and aquaculture-based selection criteria covering three aquaculture approaches of development (complete life cycle, on-growing and stock enhancement) were examined. Species were ranked according to their degree of suitability for the given biological parameters. The final classification analysis within the complete life cycle production strategy positioned the Atlantic wolffish as the top candidate species (91%) followed by the spotted wolffish and Arctic charr (87%). Growth rate, optimal growth temperature, duration of the weaning period, minimal lethal temperature, larval size and feed requirements were the determining criteria. The on-growing scenario final results ranked Arctic charr first (84%) followed by Atlantic cod (79%) and Atlantic halibut (74%) mostly owing to their growth rate at low temperature and optimal growth temperature criteria. Stock enhancement programmes should concentrate their efforts on the striped bass (56%), the haddock (54%) and the Atlantic sturgeon (34%) based on their growth rate, fishery status, landing price and the availability of impact studies. [source] The first structure of a cold-adapted superoxide dismutase (SOD): biochemical and structural characterization of iron SOD from Aliivibrio salmonicidaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009Hege Lynum Pedersen Superoxide dismutases (SODs) are metalloenzymes that catalyse the dismutation of the superoxide radical anion into O2 and H2O2 in a two-step reaction. The crystal structure of the iron superoxide dismutase from the cold-adapted and fish-pathogenic bacterium Aliivibrio salmonicida (asFeSOD) has been determined and refined to 1.7,Å resolution. The protein has been characterized and compared with the closely related homologous iron superoxide dismutase from the mesophilic Escherichia coli (ecFeSOD) in an attempt to rationalize its environmental adaptation. ecFeSOD shares 75% identity with asFeSOD. Compared with the mesophilic FeSOD, the psychrophilic FeSOD has distinct temperature differences in residual activity and thermostability that do not seem to be related to structural differences such as intramolecular or intermolecular ion bonds, hydrogen bonds or cavity sizes. However, an increased net negative charge on the surface of asFeSOD may explain its lower thermostability compared with ecFeSOD. Activity measurements and differential scanning calorimetry measurements revealed that the psychrophilic asFeSOD had a thermostability that was significantly higher than the optimal growth temperature of the host organism. [source] Effects of temperature and pH on growth and photosynthesis of the thermophilic cyanobacterium Synechococcus lividus as measured by pulse-amplitude modulated fluorometryPHYCOLOGICAL RESEARCH, Issue 4 2006Chung-Ching Liao SUMMARY In this study, the effects of five different temperatures and pH conditions on growth and photosynthetic performance of Synechococcus lividus Copeland from Taiwan were monitored in the field and the laboratory by using an underwater pulse-amplitude modulated (Diving-PAM) fluorometer. In the field, the optimal growth temperature of S. lividus was found to be 57°C. Such a finding was congruent with the growth rate in the laboratory culture, in which the optimal growth temperatures ranged from 45 to 60°C. In photosynthetic performance, the light-saturated maximum relative electron transport rate (ETRmax) and the light-limited slope (,ETR) exhibited highest values at 50°C. At five different pH conditions, higher ETRmax and ,ETR were observed from pH 7 to 9. In addition, regression analysis demonstrated a significant positive relationship between the growth rate and the ETRmax values (R2 = 0.9527), indicating that the growth of S. lividus was largely restricted to its photosynthetic performance. In conclusion, the photosynthetic performance and growth of the thermophilic cyanobacterium S. lividus were sensitive to fluctuations in temperature but not in pH. The present investigation offers a better understanding of the photosynthetic physiology. [source] | ||||||||||||||||