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991.
George Qian Michiko Toizumi Sam Clifford Lien Thuy Le Tasos Papastylianou Catherine Satzke Billy Quilty Chihiro Iwasaki Noriko Kitamura Mizuki Takegata Minh Xuan Bui Hien Anh Thi Nguyen Duc Anh Dang Albert Jan van Hoek Lay Myint Yoshida Stefan Flasche 《PLoS medicine》2022,19(5)
BackgroundInfants are at highest risk of pneumococcal disease. Their added protection through herd effects is a key part in the considerations on optimal pneumococcal vaccination strategies. Yet, little is currently known about the main transmission pathways to this vulnerable age group. Hence, this study investigates pneumococcal transmission routes to infants in the coastal city of Nha Trang, Vietnam.Methods and findingsIn October 2018, we conducted a nested cross-sectional contact and pneumococcal carriage survey in randomly selected 4- to 11-month-old infants across all 27 communes of Nha Trang. Bayesian logistic regression models were used to estimate age specific carriage prevalence in the population, a proxy for the probability that a contact of a given age could lead to pneumococcal exposure for the infant. We used another Bayesian logistic regression model to estimate the correlation between infant carriage and the probability that at least one of their reported contacts carried pneumococci, controlling for age and locality. In total, 1,583 infants between 4 and 13 months old participated, with 7,428 contacts reported. Few infants (5%, or 86 infants) attended day care, and carriage prevalence was 22% (353 infants). Most infants (61%, or 966 infants) had less than a 25% probability to have had close contact with a pneumococcal carrier on the surveyed day. Pneumococcal infection risk and contact behaviour were highly correlated: If adjusted for age and locality, the odds of an infant’s carriage increased by 22% (95% confidence interval (CI): 15 to 29) per 10 percentage points increase in the probability to have had close contact with at least 1 pneumococcal carrier. Moreover, 2- to 6-year-old children contributed 51% (95% CI: 39 to 63) to the total direct pneumococcal exposure risks to infants in this setting. The main limitation of this study is that exposure risk was assessed indirectly by the age-dependent propensity for carriage of a contact and not by assessing carriage of such contacts directly.ConclusionsIn this study, we observed that cross-sectional contact and infection studies could help identify pneumococcal transmission routes and that preschool-age children may be the largest reservoir for pneumococcal transmission to infants in Nha Trang, Vietnam. 相似文献
992.
Gwen R. Buel Huy Q. Dang John M. Asara John Blenis Anders P. Mutvei 《The Journal of biological chemistry》2022,298(6)
The mechanistic target of rapamycin complex 1 (mTORC1) is a serine/threonine kinase complex that promotes anabolic processes including protein, lipid, and nucleotide synthesis, while suppressing catabolic processes such as macroautophagy. mTORC1 activity is regulated by growth factors and amino acids, which signal through distinct but integrated molecular pathways: growth factors largely signal through the PI3K/Akt-dependent pathway, whereas the availabilities of amino acids leucine and arginine are communicated to mTORC1 by the Rag-GTPase pathway. While it is relatively well described how acute changes in leucine and arginine levels affect mTORC1 signaling, the effects of prolonged amino acid deprivation remain less well understood. Here, we demonstrate that prolonged deprivation of arginine and/or leucine leads to reactivation of mTORC1 activity, which reaches activation levels similar to those observed in nutrient-rich conditions. Surprisingly, we find that this reactivation is independent of the regeneration of amino acids by canonical autophagy or proteasomal degradation but is dependent on PI3K/Akt signaling. Together, our data identify a novel crosstalk between the amino acid and PI3K/Akt signaling pathways upstream of mTORC1. These observations extend our understanding of the role of mTORC1 in growth-related diseases and indicate that dietary intervention by removal of leucine and/or arginine may be an ineffective therapeutic approach. 相似文献
993.
The fungal genus Fusarium (Ascomycota) includes well-known plant pathogens that are implicated in diseases worldwide, and many of which have been genome sequenced. The genus also encompasses other diverse lifestyles, including species found ubiquitously as asymptomatic-plant inhabitants (endophytes). Here, we produced structurally annotated genome assemblies for five endophytic Fusarium strains, including the first whole-genome data for Fusarium chuoi. Phylogenomic reconstruction of Fusarium and closely related genera revealed multiple and frequent lifestyle transitions, the major exception being a monophyletic clade of mutualist insect symbionts. Differential codon usage bias and increased codon optimisation separated Fusarium sensu stricto from allied genera. We performed computational prediction of candidate secreted effector proteins (CSEPs) and carbohydrate-active enzymes (CAZymes)—both likely to be involved in the host–fungal interaction—and sought evidence that their frequencies could predict lifestyle. However, phylogenetic distance described gene variance better than lifestyle did. There was no significant difference in CSEP, CAZyme, or gene repertoires between phytopathogenic and endophytic strains, although we did find some evidence that gene copy number variation may be contributing to pathogenicity. Large numbers of accessory CSEPs (i.e., present in more than one taxon but not all) and a comparatively low number of strain-specific CSEPs suggested there is a limited specialisation among plant associated Fusarium species. We also found half of the core genes to be under positive selection and identified specific CSEPs and CAZymes predicted to be positively selected on certain lineages. Our results depict fusarioid fungi as prolific generalists and highlight the difficulty in predicting pathogenic potential in the group. 相似文献
994.
995.
S Q Dang 《Steroids》1986,47(6):431-434
Epimerization of 6-bromoprogesterone is observed by 1H NMR. The equilibrium constant K = 1.5 and the standard free-energy delta G = -241 cal/mol at 302 K. 相似文献
996.
Nghia HD Ho DT Tu le TP Le TP Wolbers M Thai CQ Cao QT Hoang NV Nguyen VM Nga TV Tran VT Thao le TP Le TP Phu NH Nguyen HP Chau TT Tran TH Sinh DX Dinh XS Diep TS To SD Hang HT Hoang TT Truong H Campbell J Chau NV Nguyen VV Chinh NT Nguyen TC Dung NV Nguyen VD Hoa NT Ngo TH Spratt BG Hien TT Tran TH Farrar J Schultsz C 《PloS one》2011,6(3):e17604
Background
Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease.Methods and Findings
A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating “high risk” dishes, including such dishes as undercooked pig blood and pig intestine (OR1 = 2.22; 95%CI = [1.15–4.28] and OR2 = 4.44; 95%CI = [2.15–9.15]), occupations related to pigs (OR1 = 3.84; 95%CI = [1.32–11.11] and OR2 = 5.52; 95%CI = [1.49–20.39]), and exposures to pigs or pork in the presence of skin injuries (OR1 = 7.48; 95%CI = [1.97–28.44] and OR2 = 15.96; 95%CI = [2.97–85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection.Conclusions
This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating ‘high risk’ dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infection. 相似文献997.
金针菇菌丝体的深层培养及多糖制取 总被引:1,自引:1,他引:1
从20株金针菇菌株中筛选出适于液体发酵的94B2株。该菌种适宜的摇瓶培养条件:培养温度23~24℃,pH6.5,接液体种量10%,装液量≤50ml/500ml瓶;不同的间歇振荡形式对菌丝球产量和形态有显著影响。深层发酵工艺相似于抗生素发酵。发酵期间发酵液pH变化幅度很小,总糖、还原糖、氨基氮与菌丝生长量有一定的相关性。发酵酵的菌丝产量可达47.5g(湿重)/100ml、胞外多糖达174.7kg/100ml发酵液上清、胞内多糖达338.1mg/100g湿菌丝体。 相似文献
998.
广东省南昆山药用植物资源研究 总被引:1,自引:0,他引:1
对广东南昆山的药用植物资源作了系统调查,根据标本鉴定和查阅资料,该保护区有野生药用植物180科643属1 100种,其中蕨类30科54属102种,裸子植物5科9属17种,被子植物145科580属981种.在介绍了常见药用植物的基础上,对该地药用植物资源的保护和开发利用提出了建议. 相似文献
999.
生态系统管理的基本问题 总被引:46,自引:3,他引:46
生态系统管理的基本问题赵士洞汪业勖(中国科学院国家计划委员会自然资源综合考察委员会,北京100101)SummaryonEcosystemManagement.ZhaoSidong,WangYexu(CommisionforIntegratedSur... 相似文献
1000.
Oludoyin Adeseun Adigun Muhammad Nadeem Thu Huong Pham Linda Elizabeth Jewell Mumtaz Cheema Raymond Thomas 《Plant, cell & environment》2021,44(1):1-16
Plant pathogens pose a significant threat to the food industry and food security accounting for 10–40% crop losses annually on a global scale. Economic losses from plant diseases are estimated at $300B for major food crops and are associated with reduced food availability and accessibility and also high food costs. Although strategies exist to reduce the impact of diseases in plants, many of these introduce harmful chemicals to our food chain. Therefore, it is important to understand and utilize plants' immune systems to control plant pathogens to enable more sustainable agriculture. Lipids are core components of cell membranes and as such are part of the first line of defense against pathogen attack. Recent developments in omics technologies have advanced our understanding of how plant membrane lipid biosynthesis, remodelling and/or signalling modulate plant responses to infection. Currently, there is limited information available in the scientific literature concerning lipid signalling targets and their biochemical and physiological consequences in response to plant pathogens. This review focusses on the functions of membrane lipid derivatives and their involvement in plant responses to pathogens as biotic stressors. We describe major plant defense systems including systemic‐acquired resistance, basal resistance, hypersensitivity and the gene‐for‐gene concept in this context. 相似文献