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1.
Large-scale composting facilities are known to cause environmental problems, mainly through pungent air emitted by composting material. In air samples taken above stacks set up to prepare compost used as a substrate in mushroom cultivation, several volatile compounds were identified by means of the coupled techniques of gas chromatography and mass spectrography. Among the compounds identified, sulfur-containing compounds [H2S, COS, CH3SH, CS2, (CH3)2S, (CH3)2S2, and (CH3)2S3] are the most conspicuous in causing a nuisance. Quantification of these compounds was performed by concentrating a relatively small air sample on Tenax GC. The sampling method appeared to be very useful under field conditions. During the composting process, the concentration of the volatile sulfur compounds in emitted air ranged from 1 to 35 μmol/m3. The highest concentrations were obtained at the end of the outdoor process. Total sulfur emission amounted to 8.3 mg of sulfur per kg (fresh weight) of compost. The end product still contained 2.58 g of sulfur per kg (fresh weight) of compost. Suggestions about the origin of the volatile sulfur compounds are made.  相似文献   

2.
为揭示钝叶榕与其传粉榕小蜂及两种协同进果的非传粉榕小蜂Diaziella yangi和Lipothymus sp.间的化学联系与分配机制,采用顶空动态法提取钝叶榕(Ficus curtipes Corner)雌花期和传粉后的榕果挥发物,用定性和定量的方法鉴定、分析了挥发物的成分和变化动态。结果表明:从钝叶榕榕果中共鉴定出45种挥发物成分,主要是单萜类和倍半萜类化合物。6-甲基-5-庚烯-2-酮、β-罗勒烯、反-β-金合欢烯、α-金合欢烯、α-派烯、香桧烯、顺-β-罗勒烯、顺-β-香柠檬烯、大香叶烯D和4,8-二甲基-1,3,7-壬三烯可能是构建钝叶榕特异性化学信息的基础。雌花期榕果挥发物释放量明显高于传粉后挥发物的释放量,且两者在时间和空间上存在异质性。这说明榕蜂育幼繁殖系统间存在着化学信息的联系。  相似文献   

3.
An extensive phytochemical study of the aerial parts of Vernonia guineensis Benth. (Asteraceae) led to the isolation of a new flavone, vernoguinoflavone and a naturally isolated glycerol ester, eicosanoic acid 2‐hydroxy‐1,3‐propanediyl ester, together with eighteen known secondary metabolites including quercetin, luteolin, vernopicrin, vernomelitensin, β‐amyrin, oleanolic acid, ursolic acid, lupeol, betulinic acid, β‐carotene, a mixture of stigmasterol and β‐sitosterol, β‐sitosterol‐3‐Oβ‐D‐glucoside, 2,3‐dihydroxypropyl heptacosanoate, pentacosanoic acid, docosan‐1‐ol, tritriacontan‐1‐ol, and heptatriacontan‐1‐ol. Eleven compounds are reported herein for the first time from this species. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses, particularly 1D and 2D NMR, and HR‐ESI‐MS and by comparison of their data with those reported in the literature. The crude extract, fractions and some isolated compounds were evaluated for their antibacterial activity against Gram‐negative bacteria: Escherichia coli (ATCC 25922), Shigella flexineri (NR 518), Salmonella muenchen, Salmonella typhimurium and Salmonella typhi (ATCC 19430). All the tested compounds demonstrated inhibitory activities against the tested enteric bacteria with MIC values ranging from 3.12 to 100 μg/ml. Three flavonoids isolated from the most active fraction demonstrated the best bioactivities against Escherichia coli, Salmonella muenchen and Salmonella typhimurium with MIC values ranging from 3.12 to 25 μg/mL.  相似文献   

4.
Tourova  T. P.  Sokolova  D. Sh.  Semenova  E. M.  Kireev  D. M.  Laptev  A. B.  Nazina  T. N. 《Microbiology》2022,91(6):735-749
Microbiology - The work was aimed at investigation of the composition of microbial communities formed on the surface of samples of polyethylene terephthalate (PET), polystyrene (PS) and steel (ST)...  相似文献   

5.
6.
The titan arum, Amorphophallus titanum, is a flowering plant with the largest inflorescence in the world. The flower emits a unique rotting animal-like odor that attracts insects for pollination. To determine the chemical identity of this characteristic odor, we performed gas chromatography-mass spectrometry-olfactometry analysis of volatiles derived from the inflorescence. The main odorant causing the smell during the flower-opening phase was identified as dimethyl trisulfide, a compound with a sulfury odor that has been found to be emitted from some vegetables, microorganisms, and cancerous wounds.  相似文献   

7.
Results of research into ethanol metabolism in yeast organisms with highly pronounced aerobic metabolism are reviewed. The low activity of NAD-dependent alcohol dehydrogenase (EC 1.1.1.1), observed under the conditions of aerobic yeast growth on ethanol, demonstrates that alternative enzyme systems--alcohol oxidase (EC 1.1.3.13), microsomal ethanol-oxidizing system (including cytochrome P-450), and catalase (EC 1.11.1.6)--may be involved in the alcohol oxidation. The role of these systems in alcohol oxidation and conditions favoring their operation in this processes are analyzed. It is concluded that iron ions are important regulators of ethanol metabolism the microorganisms of this group.  相似文献   

8.
Schmid R  Dring MJ 《Plant physiology》1993,101(3):907-913
In most brown algae, photosynthesis saturated with red light can be stimulated by continuous blue light. Pulses of blue light lead to transient increases in photosynthetic rate. When a CO2-sensitive electrode was used, occasionally blue light was observed to cause an apparent increase of CO2 instead of the expected decrease. This was changed by buffering the seawater medium and, under these conditions, blue light caused stimulation of CO2 consumption. These results led to investigations of blue-light-dependent pH changes at the outer surface of the plants. Shifts of the pH were recorded in the presence of the photosynthetic inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. In all brown algae tested and in the green algae Ulva and Enteromorpha, blue-light pulses caused transient acidification of 0.03 to 0.18 pH units, depending on the species. The kinetics showed lag phases of a few seconds and the minimum was reached after 5 to 9 min. Fluence response relationships indicated that the sensitivity (threshold) to blue light was very similar in all species. The responses in Ectocarpus changed with time, and about 5 h after the beginning of red light or darkness, a second component became evident, which peaked 20 min after the blue-light pulse. The refractory period of the whole system was about 3 h in Ectocarpus. The blue-light-dependent pH changes show striking similarities to those of higher plant guard cells, and it is possible that similar responses may occur in other tissues of higher plants. In red algae, however, no blue-light-dependent acidifications could be detected. The possible role of the observed pH shifts in a mechanism of CO2 acquisition is discussed.  相似文献   

9.
Doklady Biological Sciences - The degree of contamination of Saccharina latissima, the dominant species among macrophyte algae in the sublittoral zones of the Kola Bay and Eastern Murman of the...  相似文献   

10.
The green odorous f rog(Odorrana margaretae) has an interesting ring-shaped divergence pattern around the Sichuan Basin and documenting its morphological variations is essential in understanding its evolutionary history. Using curvilinear models,we detected significant geographical clinal variations in morphological traits, particularly sizes, of female O. margaretae. Males had significantly smaller sizes than females, and also had smaller variation ranges than females. One major trend of morphological variations was clinal: populations f rom the west tended to have a larger size with wider head and longer posterior limbs than populations from the east.Species history, with an early extended isolation and two subsequent secondary contacts, may explain most of the geographical clinal variations of O. margaretae.Bioclimatic factors may also contribute in explaining the variance of morphology.  相似文献   

11.
中国灵猫科的支序系统学分析   总被引:3,自引:0,他引:3  
选取分布于中国境内的8属9种灵猫科动物的88个骨骼性状、31个外部形态性状和1个行为性状,运用替代外群法分别以赤狐(犬科狐属)和青鼬(鼬科貂属)共同或单独作为外群进行支序分析,得出10个支序图,其步长(TL)为:106~136,一致性指数(CI)为0.581—0.660,保留指数(RI)为0.610—0.714。经合意分析得到4个相似的支序图,其TL为41—136,CI为0.581—0.732,RI为0.610—0.818,结果支持:①斑灵狸、大灵猫、小灵猫构成一个单系群,与传统分类一致(均属灵猫亚科);②椰子狸、花面狸、熊狸构成一个单系群,与传统分类一致(均属长尾狸亚科);③红颊獴、食蟹獴与灵猫科其他种为姐妹群关系(Bootstrap检验支持率100%),建议獴类为一亚科;④长颌带狸拥有较多自近裔性状如三个门齿孔,是一个高度特化的种类,其系统地位有待进一步研究。  相似文献   

12.
Male large odorous frogs(Odorrana graminea)have been shown to have a rich vocal repertoire and their calls contain harmonics that extend into the ultrasonic range,much like calls of male O.tormota,a sympatric species.Whereas vocalizations of male O.tormota exhibit nonlinear characteristics and contain individual signatures,it is unclear whether or not those of O.graminea do.We carried out an extensive study of the vocalizations of male O.graminea with the goal of investigating whether they:(1)contained nonlinear phenomena(NLP),(2)carried individual signatures.We recorded and analyzed 1770 vocal calls from nine males.Their calls were classifiable into two distinct categories(one-note calls and multi-note calls).Of these,one-note complex/steep-frequency modulation call was the most abundant call-type.These calls showed diverse frequency modulation patterns,and abundant presence of NLP.Various basic spectral and temporal pa ra meters of such calls were individually distinct.Kruskal-Wallis Analysis of Rank test showed that the calls from individual males differed significantly.Subsequent discriminant function analysis(DFA)showed that 54.7%of the calls could be correctly assigned to individual.These results suggested that male O.graminea might be able to discriminate neighboring frogs from strangers acoustically.However,further research is necessary to demonstrate this capacity behaviorally.  相似文献   

13.
The purpose of this article is to review non-impactor-based methods for measuring particle size distributions of orally inhaled and nasal pharmaceutical aerosols. The assessment of the size distributions of sprays and aerosols from orally inhaled and nasal drug products by methods not involving multi-stage cascade impaction may offer significant potential advantages in terms of labor savings and reducing the risk for operator-related errors associated with complex-to-undertake impactor-based methods. Indeed, in the case of nasal spray products, cascade impaction is inappropriate and alternative, and preferably non-invasive methods must be sought that minimize size-related bias associated with the measurement process for these relatively large droplets. This review highlights the options that are available to those involved with product quality assessments, providing guidance on relative strengths and weaknesses, as well as highlighting precautions that should be observed to minimize bias. The advent of Raman chemical imaging, which enables an estimate to be made of the proportion of each particle comprising active pharmaceutical ingredient(s) (APIs), necessitates a re-think about the value of classical microscopy image analysis as now being capable of providing API-relevant information from collected aerosols and sprays.  相似文献   

14.
Schwartz D 《Genetics》1973,74(4):615-617
The method of high-resolution electrophoresis was employed to compare the relative amounts of enzyme produced by the Adh1F and Adh1S alleles in heterozygotes at different stages of development. The results are in complete agreement with those obtained from enzymatic analyses and support the competition hypothesis for the regulation of the alcohol dehydrogenase gene.  相似文献   

15.
Based on a five level central composite design (CCD) involving the variables substrate concentration (C), pH (P), incubation temperature (T) and fermentation time (H), a response surface methodology (RSM) for the production of ethanol from pretreated sugarcane bagasse by cellulase and yeast Kluyveromyces fragilis was standardized. The design contains a total of 31 experimental trials in which the first 24 organized in a factorial design and from 25 to 31 involving the replications of the central points. Data obtained from RSM on ethanol production were subjected to the analysis of variance (ANOVA) and analyzed using a second order polynomial equation. Maximum ethanol concentration (32.6 g/l) was obtained from 180 g/l pretreated sugarcane bagasse at the optimized process conditions (temperature 35°C, pH 5.5) in 72 h aerobic batch fermentation. Various kinetic models such as logistic model, logistic incorporated leudeking piret model and logistic incorporated modified leudeking piret model have been evaluated and the constants were predicted.  相似文献   

16.
Growth curve data which had been fitted by use of the Gompertz and logistic functions have permitted the development of mathematical models to describe the growth of a Pectinatus sp. by several variables, namely, temperature, pH, and ethanol concentration. The activation energy of this microorganism was lower at 26 to 35(deg)C than at 15 to 22(deg)C. On the basis of the Arrhenius law, growth rate, maximum population density, and cell yield models have been developed by introducing the different activation energy (E(infa)) values. According to the model, optimal conditions were 35(deg)C, pH 6.5, and 0% (vol/vol) ethanol for the growth rate. For cell density and cell yield, optimal conditions were 32(deg)C, pH 6.0, and 1% (vol/vol) ethanol. No growth was observed for ethanol concentrations above 8% and pH values below 4.0. Other equations have also been made to describe the major end products fermented during fermentation by a Pectinatus sp. The synthesis of propionate and acetate is maximal at 28(deg)C at pHs of 5.5 and 6.25, respectively. This model completes the model suggested by Membre and Tholozan (J. Appl. Bacteriol. 77:456-460, 1994), which includes only one variable, i.e., the glucose concentration.  相似文献   

17.
18.
通过查阅有关CRC的文献资料,并结合笔者在美国参加的CRC培训、参与的美国临床试验过程,以期对我国临床试验未来的发展有些许启示作用。  相似文献   

19.
Nearly 690 raw surface water samples were collected during a 6-year period from multiple watersheds in the South Nation River basin, Ontario, Canada. Cryptosporidium oocysts in water samples were enumerated, sequenced, and genotyped by detailed phylogenetic analysis. The resulting species and genotypes were assigned to broad, known host and human infection risk classes. Wildlife/unknown, livestock, avian, and human host classes occurred in 21, 13, 3, and <1% of sampled surface waters, respectively. Cryptosporidium andersoni was the most commonly detected livestock species, while muskrat I and II genotypes were the most dominant wildlife genotypes. The presence of Giardia spp., Salmonella spp., Campylobacter spp., and Escherichia coli O157:H7 was evaluated in all water samples. The greatest significant odds ratios (odds of pathogen presence when host class is present/odds of pathogen presence when host class is absent) for Giardia spp., Campylobacter spp., and Salmonella spp. in water were associated, respectively, with livestock (odds ratio of 3.1), avian (4.3), and livestock (9.3) host classes. Classification and regression tree analyses (CART) were used to group generalized host and human infection risk classes on the basis of a broad range of environmental and land use variables while tracking cooccurrence of zoonotic pathogens in these groupings. The occurrence of livestock-associated Cryptosporidium was most strongly related to agricultural water pollution in the fall (conditions also associated with elevated odds ratios of other zoonotic pathogens occurring in water in relation to all sampling conditions), whereas wildlife/unknown sources of Cryptosporidium were geospatially associated with smaller watercourses where urban/rural development was relatively lower. Conditions that support wildlife may not necessarily increase overall human infection risks associated with Cryptosporidium since most Cryptosporidium genotypes classed as wildlife in this study (e.g., muskrat I and II genotype) do not pose significant infection risks to humans. Consequently, from a human health perspective, land use practices in agricultural watersheds that create opportunities for wildlife to flourish should not be rejected solely on the basis of their potential to increase relative proportions of wildlife fecal contamination in surface water. The present study suggests that mitigating livestock fecal pollution in surface water in this region would likely reduce human infection risks associated with Cryptosporidium and other zoonotic pathogens.  相似文献   

20.
熊猫等动物犬瘟热病毒附着蛋白基因的遗传多样性   总被引:9,自引:0,他引:9  
为了研究犬瘟热病毒(canine distemper virus,CDV)大熊猫株、小熊猫株和长春犬株附着蛋白(H)基因的遗传这异,对H基因进行了序列测定。上述3个CDV毒株的H基因全长均为1946bp,开放阅读框架(ORF)始于21-23位的ATG,终止于1842-1844位的TGA,编码607个氨基酸。与GenBank中15个CDV株推导的H蛋白氨基酸序列比较发现,16个野毒株潜在的H-联糖基  相似文献   

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