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1.
The growth of dermatophytes at 4° C and 37° C; The relation of this character to others 总被引:1,自引:1,他引:0
Summary The ability of the generaEpidermophyton, Microsporon andTrichopyton to grow on some media at 4° C and 37° C was studied. It has been shown that specific differences exist among these fungi in the capability or rapidity of the growth at extreme temperatures.There is high positive correlation among perfect state production, isolation from the soil and growth at 4° C (group of characters A) and between pathogenicity and growth at 37° C (group of characters B). Between the groups A and B of characters exists a slighter negative correlation. Some prognosis about the five characters by certain species of dermatophytes may be given. 相似文献
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Guido Barone Pasquale Cacace Giuseppina Castronuovo Vittorio Elia 《Carbohydrate research》1981,91(2):101-111
The heats of dilution in water of d-xylose, d-fructose, d-galactose, d-mannose, lactose, and raffinose have been determined calorimetrically at 25°. The calorimetric data, expressed in terms of excess enthalpy, lead to an evaluation of pair- and triplet-interaction coefficients. Osmotic data, where known, permit the analogous coefficients of the excess free energy to be obtained and thence those of the excess entropy. Analysis of the excess functions and comparison with spectroscopic properties permits some qualitative hypotheses to be formulated on the molecular interactions occurring in these solutions. 相似文献
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Marta Goberna Maria Gadermaier Carlos García Bernhard Wett Heribert Insam 《Applied and environmental microbiology》2010,76(19):6564-6571
The acclimatization of methanogens to two-phase olive mill wastes (TPOMW) was investigated in pilot fermenters started up with cattle excreta (37°C) and after changing their feed to excreta plus TPOMW (37°C or 55°C) or TPOMW alone (37°C) until a steady state was reached (28 days). Methanogenic diversity was screened using a phylogenetic microarray (AnaeroChip), and positive targets were quantified by real-time PCR. Results revealed high phylogenetic richness, with representatives of three out of the four taxonomic orders found in digesters. Methanosarcina dominated in the starting excreta (>96% of total 16S rRNA gene copies; over 45 times more abundant than any other methanogen) at high acetate (0.21 g liter−1) and ammonia N concentrations (1.3 g liter−1). Codigestion at 37°C induced a 6-fold increase of Methanosarcina numbers, correlated with CH4 production (rPearson = 0.94; P = 0.02). At 55°C, the rise in temperature and H2 partial pressure induced a burst of Methanobacterium, Methanoculleus, Methanothermobacter, and a group of uncultured archaea. The digestion of excreta alone resulted in low but constant biogas production despite certain oscillations in the methanogenic biomass. Unsuccessful digestion of TPOMW alone was attributed to high Cu levels inducing inhibition of methanogenic activity. In conclusion, the versatile Methanosarcina immediately adapted to the shift from excreta to excreta plus TPOMW and was responsible for the stimulated CH4 production at 37°C. Higher temperatures (55°C) fostered methanogenic diversity by promoting some H2 scavengers while yielding the highest CH4 production. Further testing is needed to find out whether there is a link between increased methanogenic diversity and reactor productivity.Turning residues into energy is a societal and scientific priority due to climate change, fossil fuel exhaustion, and waste accumulation. In 2006, in Europe (EU27), less than 3% of electricity production came from biomass and wastes (11). Biogas plants, which anaerobically treat organic wastes to produce energy, are increasingly promoted in Europe, but their distribution is highly biased (35). While thousands of full- and farm-scale biogas plants are spread over central and northern Europe, anaerobic digestion technology in Mediterranean countries—Portugal, Spain, Italy, Greece, and Turkey—is in its early stages (35). These nations and other circum-Mediterranean countries lead in the production of olive oil and thus in olive mill wastes and wastewaters, which have a huge biogas production potential due to their lipid composition (1). Spain alone generates one-third of the world''s oil production and millions of tons of two-phase olive mill wastes (TPOMW) per year. TPOMW are mostly burned or composted (28), hence releasing methane into the atmosphere. This compels a change in strategy: methane production from TPOMW should be optimized in engineered environments and transformed into energy.TPOMW is a humid residue containing the olive pulp and stone. Its anaerobic digestibility is hampered by its low pH, low ammonia N, and high content in antimicrobial substances (1). However, it has been successfully fermented under laboratory conditions by supplementing it with nutrients and increasing the reactor organic loading rate stepwise (2) or by codigesting it with residues with a high buffering capacity, e.g., cattle excreta (17). These approaches seem to facilitate the adaptation of the methane-producing anaerobic community to the environmental conditions that TPOMW impose.Methanogenic archaea—microbes clustered within five orders of the Euryarchaeota—constitute the last step in the trophic chain of decomposers degrading organic matter in oxygen-free environments (36). Methanogenesis is often the rate-limiting step of anaerobic digestion of organic wastes (3) due to the fast duplication times of bacteria, which generate all substrates for the slow-growing methane-producing archaea. It is also the most sensitive step in processing imbalances (4), likely due to the lack of functional redundancy among methanogens (8). High concentrations of volatile fatty acids, salts, ammonia, and heavy metals can be inhibitory for methanogens (5, 22) and are the most common reasons for reactor failure (3). Our objective was to understand the adaptation of methanogenic communities to TPOMW. We investigated methanogenic diversity and abundance in pilot digesters fed with cattle excreta and after changing their feed to TPOMW or TPOMW plus excreta. We expected that mixing both residues would allow a faster adaptation and more efficient performance of the methanogenic communities in digesting TPOMW. The cofermentation was evaluated at 37°C and 55°C. During an acclimatization period of 28 days, we screened the methanogenic diversity using an in-house-devised phylogenetic microarray, the AnaeroChip (13), and quantified dominant genera by real-time quantitative PCR (qPCR). We have taken primers from the literature, and we present four new sets of genus-specific primers and SYBR green I-optimized assays for quantifying methanogens in anaerobic environments. 相似文献
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Zhaoqi Wang Jinfeng Chang Shushi Peng Shilong Piao Philippe Ciais Richard Betts 《Journal of Plant Ecology》2019,12(5):804
Aims
The impacts of future global warming of 1.5°C and 2°C on the productivity and carbon (C) storage of grasslands in China are not clear yet, although grasslands in China support ~45 million agricultural populations and more than 238 million livestock populations, and are sensitive to global warming. 相似文献
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Capacity to synthesize glucose, urea, and ketone bodies is well maintained in hepatocytes after storage for at least 24 h at 4 degrees C. Substrates and albumin are the only requirements. 相似文献
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Summary H1° histones were purified by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis from human lung carcinoma (line DMS79), human hepatoblastoma (HepG2), human adult lung and human adult and fetal liver. The purified human H1° histones were analyzed for their amino acid composition and terminal residues. The comparative analysis of the amino acid compositions of the different human H1° histones showed that: (a) all the H1° preparations have the characteristically high lysine content associated with a low arginine content, which distinguishes outer histones from core histones; (b) H1° is distinguishable from other H1 histones by the presence of methionine and histidine; (c) H1° histones from human adult, fetal and cancer cells are very similar in amino acid composition, and in cancer cells the level of the H1° histone is not inversely related with cell growth rate nor with the expression of the -fetoprotein gene. 相似文献
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Fluorescence induction at ?196°C has been monitored in chloroplasts rapidly frozen after poising at different redox potentials at room temperature. It was found that, as at room temperature, the initial level of fluorescence observed upon shutter opening (Fo), relative to the final level observed after 10 seconds of illumination (Fm) increased as the redox potential of the chloroplasts was lowered. Redox titration revealed the presence of two quenching components with Em,7.8 at ?70 mV and ?275 mV accounting for approx. 75% and 25% of the variable fluorescence (Fv). Parallel observation of fluorescence yield at room temperature similarly gave two components, with Em,7.8 at ?95 mV and ?290 mV, also accounting for approx. 75% and 25%. Simultaneous measurement of fluorescence emission at ?196°C at 695 nm and 735 nm indicated that both emissions are quenched by the same redox components. 相似文献
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Summary The distribution of phytoplankton along transects amounting to about 10,000 nautical miles in the sector of the Southern Ocean between 20° and 70°W was determined during the austral summer of 1978/79. Chlorophyll a concentration was monitored by the continuous measurement of in vivo fluorescence (IVF). Surface samples were collected for the determination of temperature, salinity, chlorophyll a concentration, carbon fixation rate and species of the phytoplankton. Phytoplankton distribution was found to be extremely patchy both locally and regionally. High phytoplankton concentrations were often associated with either hydrographic features, such as upwelling or the presence of sea-ice, or with bathymetric features, such as shelf breaks, submarine mountain ranges or islands. Enrichment experiments, in which the effects of various nutrient additions on the rate of 14C fixation by the natural phytoplankton were compared, and bioassay experiments, in which the growth of Thalassiosira pseudonana (Hustedt) Hasle and Heimdal in enriched water samples was measured, were carried out using water samples collected at various stations throughout the study area. Although these techniques were effective in demonstrating nutrient limitation elsewhere, the results suggest that availability of nitrate, phosphate, silicate, trace metals or vitamins exerts no primary control over phytoplankton abundance south of the Polar Front. 相似文献
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Summary Geographical distribution of biomass and species, community structure, and size comparisons of pelagic shrimps were investigated in the upper 1000m in the Southern Ocean between 150° E and 115° E during the austral summer (December 1985 and January 1986). The biomass ranged from 0 to 4.25 g wet weight/1000 m3 collected by the IKMT and in general tended to decrease southward. The average biomass north of the Polar Front and in the Antarctic Zone was 2.55 and 0.40 g/1000 m3, respectively. Twenty species were collected and of these eight were in the Antarctic Zone. Pelagic shrimps in the study area were assigned to four categories by their geographical distribution. The first included five upper meso-pelagic species and was restricted to the Subtropical Zone. The second included seven lower meso-pelagic species and occurred in the Subtropical and Subantarctic Zones. The third included seven lower meso-and bathy-pelagic species and was distributed from the Subtropical Zone to the Antartic Zone. The fourth category of one species was distributed from the Subantarctic Zone to the Antarctic Zone. We suggest that oceanic fronts in the study area do not constitute a distributional barrier to lower meso-and bathy-pelagic shrimps. 相似文献
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Histone H1 of rat alveolar macrophages, neutrophilic granulocytes and monocytes extracted with 5% (v/v) perchloric acid was studied in order to see whether a protein similar to histone H1° of rat liver exists in these specialized cells. The biochemical methods used involved SDS and acid-urea polyacrylamide gel electrophoresis, gel filtration on BioGel P100 and raising antisera against chromatographically purified rat liver H1° and histone H1. The antiserum was applied for further characterization of the presumptive H1° fraction using ELISA and Western blot analysis.The results from our studies showed that histone H1° protein is present in rat alveolar macrophages, monocytes and neutrophilic granulocytes, but its quantity in neutrophilic granulocytes is very much less than macrophages and monocytes. 相似文献
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Experiments were carried out to find the effect of dark-holding in distilled water at 4° C on recovery of Gamma- and UV-irradiated cells of a haploid strain ofSaccharomyces carlsbergensis. It was found that there was an appreciable increase in survival of the irradiated cells following 4 to 24 hours' holding while no increase in the number of control cells was observed following similar treatment. It is suggested that some common type of damage induced by both Gamma- and UV-radiations inS. carlsbergensis may be repaired efficiently under metabolic conditions associated with growth at 4° C in distilled water. 相似文献
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B. Henderson N. Loverdge W. R. Robertson M. T. Smith 《Histochemistry and cell biology》1981,72(4):545-550
Summary Blocks of tissue from various organs of the rat have been chilled by precipitate immersion in n-hexane cooled to –70° C, and then stored at –70° C. At various intervals (up to 14 days) after chilling, cryostat sections were prepared from these blocks and assayed for the activity of a variety of enzymes. Enzyme activity was measured by scanning and integrating microdensitometry. With the exception of acid phosphatase and cytochrome oxidase, all enzymes assayed were stable for at least 7 days after storage at –70° C and most were stable for 14 days. Storage of fresh-frozen sections at –30° C in the cabinet of the cryostat, for up to 24 h, had little effect on enzyme activity. 相似文献
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The long-term preservation of whole organs will almost certainly require the use of subzero temperatures and cryoprotectants. An essential part of such a technique is the ability to add a cryoprotectant in adequate concentration and subsequently to remove it without damage to the organ. In this study rabbit kidneys have been perfused with solutions containing 3% dextran and 2 m glycerol at 5 °C, and their function has been measured after removal of the glycerol. The assay technique involved the measurement of glomerular filtration rate, protein leakage, and tubular reabsorption of sodium and glucose. The results indicate that the inclusion in the perfusate of an impermeant solute (mannitol) and limitation of the rate of change of glycerol concentration (to 30 mm min?1) permits rabbit kidneys to retain a degree of function similar to that found in perfused control kidneys, although somewhat reduced in comparison with freshly isolated kidneys. 相似文献
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This article reports the effect of cold storage at 4 °C from December to April on chestnut cuttings. Rooting was found to
increase after four months preceded by treatment with 4000 mg l-1 IBA.
ThePhaseolus test of the biological activity of extracts of the cuttings showed the inhibition exerted by the acid fraction of the fresh
(December) cuttings to have been replaced by a rootpromoting effect in cuttings stored for 4 months at low temperature. Cold
storage thus seems to favour rooting. 相似文献
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Variability of physiological parameters of unacclimatized males during a two—hour cold stress of 5°C
The metabolic and temperature responses of 11 male Caucasians to a 2-hr exposure to 5 ± 1°C, 70 ± 2% RH were compared with control data obtained in an ambient environment of 28 ± 1°C, 45 ± 2% RH. The heat production increased during the cold exposure attaining an approximately stable level during the final 30 min. The group variability in response to the cold was greatest during the first 30 min and declined for the remainder of the cold exposure. All skin temperatures approached a stable value during the final 30 min of cold exposure. The correlation between mean skin temperature and thigh temperature was significant (p < 0.001) and the use of thigh temperature as an approximate mean skin temperature was suggested. The calculation of tissue conductance with or without the inclusion of heat exchanges due to changes in body heat content and respiratory losses was in agreement only during the final 30 min of cold exposure, thus indicating a stage of physiological equilibrium. All measured parameters except the toe and finger temperatures approached minimum variability of response during the final 30 min of cold exposure.
Supported in part by United States Public Health Service Grant No. HD-00235; and the Air Force Office of Scientific Research, Office of Aerospace Research, United States Air Force, under AFOSR Grant No. 69-1653. Data analysis (on IBM System 360 Model 75 computer) was made possible by funds from the Special Research Resources Branch, Division of Research Facilities and Resources, National Institutes of Health. 相似文献
Zusammenfassung Die Reaktionen des Stoffwechsels und der Hauttemperatur von 11 männlichen Angehörigen der weissen Rasse während einer 2-stündigen Exponierung bei 5 ± 1°C, 50–70 % RF wurden mit den Kontrollwerten bei 28 ± 1°C und 45 ± 2% RF verglichen. Während der Kälteexponierung stieg die Wärmebildung an und erreichte wie die Hauttemperatur in den letzten 30 Min ein ungefähr konstantes Niveau. Die Gruppenvariabilität war in den ersten 30 Min am grössten und liess dann nach. Die Korrelation zwischen mittlerer Hauttemperatur und Oberschenkeltemperatur war hochsignifikant (p < 0,001). Es wird vorgeschlagen letztere als mittlere Hauttemperatur zu verwenden. Die Berechnung der Gewebeleitfähigkeit mit oder ohne Einbeziehung des Wärmeaustausches als Folge von Änderungen des Wärmegehaltes des Körpers und Wärmeverlustes bei der Atmung stimmte nur während der letzten 30 Min. Alle gemessenen Parameter ausser der Zehen- und Fingertemperatur näherten sich während der letzten 30 Min der Kälteexponierung einer minimalen Variabilität. Dies weist auf ein physiologisches Gleichgewicht hin.
Resume On a comparé le métabolisme et la température cutanée de 11 personnes de la race blanche caucasienne exposées durant 2 heures à une température de 5 ± 1°C et à une humidité relative de 70 ± 2% aux mêmes valeurs obtenues par 28 ± 1°C et 45 ± 2%. La production de chaleur a augmenté durant l'exposition au froid pour atteindre un niveau relativement stable durant les 30 dernières minutes. La variabilité du groupe quant à la réaction au froid fut très importante durant les 30 premières minutes. Elle a notablement diminué le reste du temps. Toutes les températures cutanées se sont stabilisées durant les 30 dernières minutes de l'exposition au froid. La corrélation entre la température de la peau et celle de la cuisse fut hautement significative (p < 0,001) et l'on propose d'utiliser cette dernière température comme température cutanée moyenne. Le calcul de la conductibilité des tissus en y incluant ou excluant les échanges de chaleur dus aux variations thermiques du corps ou les pertes imputables à la respiration n'est exact que pour les 30 dernières minutes. Tous les paramètres mesurés, à l'exception des températures des doigts et des orteils tendent vers un minimum de variabilité durant ce même laps de temps. Ceci indique qu'un état d'équilibre physiologique est alors atteint.
Supported in part by United States Public Health Service Grant No. HD-00235; and the Air Force Office of Scientific Research, Office of Aerospace Research, United States Air Force, under AFOSR Grant No. 69-1653. Data analysis (on IBM System 360 Model 75 computer) was made possible by funds from the Special Research Resources Branch, Division of Research Facilities and Resources, National Institutes of Health. 相似文献
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Nakamura K Watanabe H Miyazaki J Takai K Kawagucci S Noguchi T Nemoto S Watsuji TO Matsuzaki T Shibuya T Okamura K Mochizuki M Orihashi Y Ura T Asada A Marie D Koonjul M Singh M Beedessee G Bhikajee M Tamaki K 《PloS one》2012,7(3):e32965
Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and are host to many novel genera and families of animals, potentially indigenous to Indian Ocean hydrothermal systems. In particular, since its discovery in 2001, much attention has been paid to a so-called 'scaly-foot' gastropod because of its unique iron-sulfide-coated dermal sclerites and the chemosynthetic symbioses in its various tissues. Despite increasing interest in the faunal assemblages at Indian Ocean hydrothermal vents, only two hydrothermal vent fields have been investigated in the Indian Ocean. Here we report two newly discovered hydrothermal vent fields, the Dodo and Solitaire fields, which are located in the Central Indian Ridge (CIR) segments 16 and 15, respectively. Chemosynthetic faunal communities at the Dodo field are emaciated in size and composition. In contrast, at the Solitaire field, we observed faunal communities that potentially contained almost all genera found at CIR hydrothermal environments to date, and even identified previously unreported taxa. Moreover, a new morphotype of 'scaly-foot' gastropod has been found at the Solitaire field. The newly discovered 'scaly-foot' gastropod has similar morphological and anatomical features to the previously reported type that inhabits the Kairei field, and both types of 'scaly-foot' gastropods genetically belong to the same species according to analyses of their COI gene and nuclear SSU rRNA gene sequences. However, the new morphotype completely lacks an iron-sulfide coating on the sclerites, which had been believed to be a novel feature restricted to 'scaly-foot' gastropods. Our new findings at the two newly discovered hydrothermal vent sites provide important insights into the biodiversity and biogeography of vent-endemic ecosystems in the Indian Ocean. 相似文献