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11.
Experiments with mixed cultures ofEscherichia coli, Desulfovibrio vulgaris, andChromatium vinosum were conducted using a synthetic medium with glucose as the substrate. The bacterial number and the changes in the chemical
factors were determined during the development of the mixed culture. (i) Fermentation of glucose byE. coli produces organic acids (formic, acetic, lactic, and succinic) and alcohol. The growth-yield constant K (cell dry weight per
weight solid substrate) does not exceed 0.05. (ii) In the mixed culture ofE. coli andD. vulgaris, the reduction of sulfate is accompanied by a total consumption of formate, lactate, and alcohol and an increase in the sulfide
and acetate content. (iii) When the three physiologically different species are allowed to grow simultaneously, there is no
accumulation of catabolites in the medium and the growth yield constant increases to 0.46. Maximum phototrophic production
requires the presence of bothE. coli andD. vulgaris. A low substrate concentration and the simultaneous growth of the three organisms are other factors that contribute towards
a high output. The biochemical parameters of the medium are influenced to a large extent by the glucose level. The results
suggest that the behavior of the strains is different in pure and mixed cultures. 相似文献
12.
Renee M. van Dorst Christine Argillier Sandra Brucet Kerstin Holmgren Pietro Volta Ian J. Winfield Thomas Mehner 《Ecology and evolution》2022,12(7)
An organism''s body size plays an important role in ecological interactions such as predator–prey relationships. As predators are typically larger than their prey, this often leads to a strong positive relationship between body size and trophic position in aquatic ecosystems. The distribution of body sizes in a community can thus be an indicator of the strengths of predator–prey interactions. The aim of this study was to gain more insight into the relationship between fish body size distribution and trophic position in a wide range of European lakes. We used quantile regression to examine the relationship between fish species'' trophic position and their log‐transformed maximum body mass for 48 fish species found in 235 European lakes. Subsequently, we examined whether the slopes of the continuous community size distributions, estimated by maximum likelihood, were predicted by trophic position, predator–prey mass ratio (PPMR), or abundance (number per unit effort) of fish communities in these lakes. We found a positive linear relationship between species'' maximum body mass and average trophic position in fishes only for the 75% quantile, contrasting our expectation that species'' trophic position systematically increases with maximum body mass for fish species in European lakes. Consequently, the size spectrum slope was not related to the average community trophic position, but there were negative effects of community PPMR and total fish abundance on the size spectrum slope. We conclude that predator–prey interactions likely do not contribute strongly to shaping community size distributions in these lakes. 相似文献
13.
Pseudo‐nitzschia arctica sp. nov., a new cold‐water cryptic Pseudo‐nitzschia species within the P. pseudodelicatissima complex 下载免费PDF全文
14.
Elf5 is essential for early embryogenesis and mammary gland development during pregnancy and lactation 下载免费PDF全文
Zhou J Chehab R Tkalcevic J Naylor MJ Harris J Wilson TJ Tsao S Tellis I Zavarsek S Xu D Lapinskas EJ Visvader J Lindeman GJ Thomas R Ormandy CJ Hertzog PJ Kola I Pritchard MA 《The EMBO journal》2005,24(3):635-644
Elf5 is an epithelial-specific ETS factor. Embryos with a null mutation in the Elf5 gene died before embryonic day 7.5, indicating that Elf5 is essential during mouse embryogenesis. Elf5 is also required for proliferation and differentiation of mouse mammary alveolar epithelial cells during pregnancy and lactation. The loss of one functional allele led to complete developmental arrest of the mammary gland in pregnant Elf5 heterozygous mice. A quantitative mRNA expression study and Western blot analysis revealed that decreased expression of Elf5 correlated with the downregulation of milk proteins in Elf5(+/-) mammary glands. Mammary gland transplants into Rag(-/-) mice demonstrated that Elf5(+/-) mammary alveolar buds failed to develop in an Elf5(+/+) mammary fat pad during pregnancy, demonstrating an epithelial cell autonomous defect. Elf5 expression was reduced in Prolactin receptor (Prlr) heterozygous mammary glands, which phenocopy Elf5(+/-) glands, suggesting that Elf5 and Prlr are in the same pathway. Our data demonstrate that Elf5 is essential for developmental processes in the embryo and in the mammary gland during pregnancy. 相似文献
15.
Clarissa Neves Spitz Roberto Mogami Izabela Jardim Rodrigues Pitta Mariana Andrea Vilas Boas Hacker Anna Maria Sales Euzenir Nunes Sarno Marcia Rodrigues Jardim 《PLoS neglected tropical diseases》2022,16(4)
Leprosy is still a prevalent disease in Brazil, representing 93% of all occurrences in the Americas. Leprosy neuropathy is one of the most worrying manifestations of the disease. Acute neuropathy usually occurs during reaction episodes and is called neuritis. Twenty-two leprosy patients were included in this study. These patients had neural pain associated with ulnar sensory neuropathy, with or without adjunct motor involvement. The neurological picture began within thirty days of the clinical evaluation. The patients underwent a nerve conduction study and the demyelinating findings confirmed the diagnosis of neuritis. Ultrasonographic study (US) of the ulnar nerve was performed in all patients by a radiologist who was blinded to the clinical or neurophysiological results. Morphological characteristics of the ulnar nerve were analyzed, such as echogenicity, fascicular pattern, transverse cross-sectional area (CSA), aspect of the epineurium, as well as their anatomical relationships. The volume of selected muscles referring to the ulnar nerve, as well as their echogenicity, was also examined. Based on this analysis, patients with increased ulnar nerve CSA associated with loss of fascicular pattern, epineurium hyperechogenicity and presence of power Doppler flow were classified as neuritis. Therefore, patients initially classified by the clinical-electrophysiological criteria were reclassified by the imaging criteria pre-established in this study as with and without neuritis. Loss of fascicular pattern and flow detection on power Doppler showed to be significant morphological features in the detection of neuritis. In 38.5% of patients without clinical or neurophysiological findings of neuritis, US identified power Doppler flow and loss of fascicular pattern. The US is a method of high resolution and portability, and its low cost means that it could be used as an auxiliary tool in the diagnosis of neuritis and its treatment, especially in basic health units. 相似文献
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18.
Holly M. Biggs Julian T. Hertz O. Michael Munishi Renee L. Galloway Florian Marks Wilbrod Saganda Venance P. Maro John A. Crump 《PLoS neglected tropical diseases》2013,7(12)
Background
The incidence of leptospirosis, a neglected zoonotic disease, is uncertain in Tanzania and much of sub-Saharan Africa, resulting in scarce data on which to prioritize resources for public health interventions and disease control. In this study, we estimate the incidence of leptospirosis in two districts in the Kilimanjaro Region of Tanzania.Methodology/Principal Findings
We conducted a population-based household health care utilization survey in two districts in the Kilimanjaro Region of Tanzania and identified leptospirosis cases at two hospital-based fever sentinel surveillance sites in the Kilimanjaro Region. We used multipliers derived from the health care utilization survey and case numbers from hospital-based surveillance to calculate the incidence of leptospirosis. A total of 810 households were enrolled in the health care utilization survey and multipliers were derived based on responses to questions about health care seeking in the event of febrile illness. Of patients enrolled in fever surveillance over a 1 year period and residing in the 2 districts, 42 (7.14%) of 588 met the case definition for confirmed or probable leptospirosis. After applying multipliers to account for hospital selection, test sensitivity, and study enrollment, we estimated the overall incidence of leptospirosis ranges from 75–102 cases per 100,000 persons annually.Conclusions/Significance
We calculated a high incidence of leptospirosis in two districts in the Kilimanjaro Region of Tanzania, where leptospirosis incidence was previously unknown. Multiplier methods, such as used in this study, may be a feasible method of improving availability of incidence estimates for neglected diseases, such as leptospirosis, in resource constrained settings. 相似文献19.
Ai-Hsiang Chou Chia-Chyi Liu Jui-Yuan Chang Renee Jiang Yi-Chin Hsieh Amanda Tsao Chien-Long Wu Ju-Lan Huang Chang-Phone Fung Szu-Min Hsieh Ya-Fang Wang Jen-Ren Wang Mei-Hua Hu Jen-Ron Chiang Ih-Jen Su Pele Choi-Sing Chong 《PloS one》2013,8(11)