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1.
Zhang L Kinkelaar D Huang Y Li Y Li X Wang HH 《Applied and environmental microbiology》2011,77(20):7134-7141
The rapid emergence of antibiotic resistance (AR) is a major public health concern. Recent findings on the prevalence of food-borne antibiotic-resistant (ART) commensal bacteria in ready-to-consume food products suggested that daily food consumption likely serves as a major avenue for dissemination of ART bacteria from the food chain to human hosts. To properly assess the impact of various factors, including the food chain, on AR development in hosts, it is important to determine the baseline of ART bacteria in the human gastrointestinal (GI) tract. We thus examined the gut microbiota of 16 infant subjects, from the newborn stage to 1 year of age, who fed on breast milk and/or infant formula during the early stages of development and had no prior exposure to antibiotics. Predominant bacterial populations resistant to several antibiotics and multiple resistance genes were found in the infant GI tracts within the first week of age. Several ART population transitions were also observed in the absence of antibiotic exposure and dietary changes. Representative AR gene pools including tet(M), ermB, sul2, and bla(TEM) were detected in infant subjects. Enterococcus spp., Staphylococcus spp., Klebsiella spp., Streptococcus spp., and Escherichia coli/Shigella spp. were among the identified AR gene carriers. ART bacteria were not detected in the infant formula and infant foods examined, but small numbers of skin-associated ART bacteria were found in certain breast milk samples. The data suggest that the early development of AR in the human gut microbiota is independent of infants' exposure to antibiotics but is likely impacted by exposure to maternal and environmental microbes during and after delivery and that the ART population is significantly amplified within the host even in the absence of antibiotic selective pressure. 相似文献
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Cell death can be divided into the anti-inflammatory process of apoptosis and the
pro-inflammatory process of necrosis. Necrosis, as apoptosis, is a regulated form of cell
death, and Poly-(ADP-Ribose) Polymerase-1 (PARP-1) and Receptor-Interacting Protein (RIP)
1/3 are major mediators. We previously showed that absence or inhibition of PARP-1
protects mice from nephritis, however only the male mice. We therefore hypothesized that
there is an inherent difference in the cell death program between the sexes. We show here
that in an immune-mediated nephritis model, female mice show increased apoptosis compared
to male mice. Treatment of the male mice with estrogens induced apoptosis to levels
similar to that in female mice and inhibited necrosis. Although PARP-1 was activated in
both male and female mice, PARP-1 inhibition reduced necrosis only in the male mice. We
also show that deletion of RIP-3 did not have a sex bias. We demonstrate here that male
and female mice are prone to different types of cell death. Our data also suggest that
estrogens and PARP-1 are two of the mediators of the sex-bias in cell death. We therefore
propose that targeting cell death based on sex will lead to tailored and better treatments
for each gender. 相似文献
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Giselle Aparecida Fagundes-Silva Gustavo Adolfo Sierra Romero Elisa Cupolillo Ellen Priscila Gadelha Yamashita Adriano Gomes-Silva Jorge Augusto de Oliveira Guerra Alda Maria Da-Cruz 《Memórias do Instituto Oswaldo Cruz》2015,110(6):797-800
In the Brazilian Amazon, American tegumentary leishmaniasis (ATL) is endemic and
presents a wide spectrum of clinical manifestations due, in part, to the circulation
of at least seven Leishmania species. Few reports of
Leishmania (Viannia) naiffi infection suggest that its occurrence
is uncommon and the reported cases present a benign clinical course and a good
response to treatment. This study aimed to strengthen the clinical and
epidemiological importance of L. (V.) naiffi in the Amazon Region
(Manaus, state of Amazonas) and to report therapeutic failure in patients infected
with this species. Thirty Leishmania spp samples isolated from
cutaneous lesions were characterised by multilocus enzyme electrophoresis. As
expected, the most common species was Leishmania (V.) guyanensis (20
cases). However, a relevant number ofL. (V.) naiffi patients (8
cases) was observed, thus demonstrating that this species is not uncommon in the
region. No patient infected withL. (V.) naiffi evolved to
spontaneous cure until the start of treatment, which indicated that this species may
not have a self-limiting nature. In addition, two of the patients experienced a poor
response to antimonial or pentamidine therapy. Thus, either ATL cases due to
L. (V.) naiffi cannot be as uncommon as previously thought or
this species is currently expanding in this region. 相似文献
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Durbadal Ojha Rashmi Das Parveen Sobia Vedprakash Dwivedi Soma Ghosh Amalesh Samanta Debprasad Chattopadhyay 《PloS one》2015,10(9)
Pedilanthus tithymaloides (PT), a widely used ethnomedicinal plant, has been employed to treat a number of skin conditions. To extend its utility and to fully exploit its medicinal potential, we have evaluated the in vitro antiviral activity of a methanolic extract of PT leaves and its isolated compounds against Herpes Simplex Virus type 2 (HSV-2). Bioactivity-guided studies revealed that the extract and one of its constituents, luteolin, had potent antiviral activity against wild-type and clinical isolates of HSV-2 (EC50 48.5–52.6 and 22.4–27.5 μg/ml, respectively), with nearly complete inhibition at 86.5–101.8 and 40.2–49.6 μg/ml, respectively. The inhibitory effect was significant (p<0.001) when the drug was added 2 h prior to infection, and was effective up to 4 h post-infection. As viral replication requires NF-κB activation, we examined whether the observed extract-induced inhibition of HSV-2 was related to NF-κB inhibition. Interestingly, we observed that treatment of HSV-2-infected cells with extract or luteolin suppressed NF-κB activation. Although NF-κB, JNK and MAPK activation was compromised during HSV replication, neither the extract nor luteolin affected HSV-2-induced JNK1/2 and MAPK activation. Moreover, the PT leaf extract and luteolin potently down-regulated the expression of tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, IL-6, NO and iNOS and the production of gamma interferon (IFN-γ), which are directly involved in controlling the NF-κB signaling pathway. Thus, our results indicate that both PT leaf extract and luteolin modulate the NF-κB signaling pathway, resulting in the inhibition of HSV-2 replication. 相似文献
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Fernando Fonseca Val Vanderson Souza Sampaio Maria Belén Cassera Raquel Tapajós Andrade Pedro Luiz Tauil Wuelton Marcelo Monteiro Marcus Vinícius Guimar?es Lacerda 《Memórias do Instituto Oswaldo Cruz》2014,109(5):522-524
In the 1950s, the strategy of adding chloroquine to food salt as a prophylaxis
against malaria was considered to be a successful tool. However, with the development
of Plasmodium resistance in the Brazilian Amazon, this control
strategy was abandoned. More than 50 years later, asexual stage resistance can be
avoided by screening for antimalarial drugs that have a selective action against
gametocytes, thus old prophylactic measures can be revisited. The efficacy of the old
methods should be tested as complementary tools for the elimination of malaria. 相似文献
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Maryline Paris Cécile Tourrel-Cuzin Cédric Plachot Alain Ktorza 《Experimental diabetes research》2004,5(2):111-121
β-cell neogenesis triggers the generation of new β-cells
from precursor cells. Neogenesis from duct epithelium is the
most currently described and the best documented process
of differentiation of precursor cells into β-cells. It is contributes
not only to β-cell mass expansion during fetal and
nonatal life but it is also involved in the maintenance of the
β-cell mass in adults. It is also required for the increase in
β-cell mass in situations of increase insulin demand (obesity,
pregnancy). A large number of factors controlling the differentiation
of β-cells has been identified. They are classified
into the following main categories: growth factors, cytokine
and inflamatory factors, and hormones such as PTHrP and
GLP-1. The fact that intestinal incretin hormone GLP-1
exerts a major trophic role on pancreatic β-cells provides
insights into the possibility to pharmacologically stimulate
β-cell neogenesis. This could have important implications
for the of treatment of type 1 and type 2 diabetes. Transdifferentiation,
that is, the differentiation of already differentiated
cells into β-cells, remains controversial.However, more
and more studies support this concept. The cells, which can
potentially “transdifferentiate” into β-cells, can belong to
the pancreas (acinar cells) and even islets, or originate from
extra-pancreatic tissues such as the liver. Neogenesis from intra-islet precursors also have been proposed and subpopulations
of cell precursors inside islets have been described
by some authors. Nestin positive cells, which have been considered
as the main candidates, appear rather as progenitors
of endothelial cells rather than β-cells and contribute to
angiogenesis rather than neogenesis. To take advantage of
the different differentiation processes may be a direction for
future cellular therapies. Ultimately, a better understanding
of the molecular mechanisms involved in β-cell neogenesis
will allow us to use any type of differentiated and/or undifferentiated
cells as a source of potential cell precursors. 相似文献
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A new genus of Isotomidae, Bellisotoma
gen. n., is described. The new genus is a member of the Proisotoma genus complex and is characterized by a combination of having a bidentate mucro with wide dorsal lamellae that join clearly before the end of mucronal axis without forming a tooth and one strong ventral rib with basal notch that articulates with dens; having abundant chaetotaxy on both faces of dens; and abundant tergal sensilla. Bellisotoma gen. n. shows a furcula adapted to a neustonic mode of life, and may be a Isotopenola-like derivative adapted to neustonic habitats. Subisotoma joycei Soto-Adames & Giordano, 2011 and Ballistura ewingi James, 1933 are transferred to the new genus. 相似文献
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The tiger beetle fauna of the Balkan Peninsula is one of the richest in Europe and includes 19 species or 41% of the European tiger beetle fauna. Assembled by their biogeographical origins, the Balkan tiger beetle species fall into 14 different groups that include, Mediterranean, Middle Oriental, Central Asiatic, Euro-Siberian, South and East European, Pannonian-Sarmatian, West Palaearctic, Turano-European and Afrotropico Indo-Mediterranean species. The Mediterranean Sclerophyl and the Pontian Steppe are the Balkan biogeographical provinces with the highest species richness, while the Balkan Highlands has the lowest Cicindelidae diversity. Most species are restricted to single habitat types in lowland areas of the Balkan Peninsula and only Calomera aulica aulica and Calomera littoralis nemoralis occur in respectively 3 and 4 different types of habitat. About 60% of all Balkan Cicindelidae species are found in habitats potentially endangered by human activity. 相似文献
18.
Does Leaf Position within a Canopy Affect Acclimation of
Photosynthesis to Elevated CO2?
: Analysis of a Wheat Crop under Free-Air CO2
Enrichment 总被引:1,自引:0,他引:1 下载免费PDF全文
Colin P. Osborne Julie La Roche Richard L. Garcia Bruce A. Kimball Gerard W. Wall Paul J. Pinter Jr. Robert L. La Morte George R. Hendrey Steve P. Long 《Plant physiology》1998,117(3):1037-1045
Previous studies of photosynthetic acclimation to elevated CO2 have focused on the most recently expanded, sunlit leaves in the canopy. We examined acclimation in a vertical profile of leaves through a canopy of wheat (Triticum aestivum L.). The crop was grown at an elevated CO2 partial pressure of 55 Pa within a replicated field experiment using free-air CO2 enrichment. Gas exchange was used to estimate in vivo carboxylation capacity and the maximum rate of ribulose-1,5-bisphosphate-limited photosynthesis. Net photosynthetic CO2 uptake was measured for leaves in situ within the canopy. Leaf contents of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), light-harvesting-complex (LHC) proteins, and total N were determined. Elevated CO2 did not affect carboxylation capacity in the most recently expanded leaves but led to a decrease in lower, shaded leaves during grain development. Despite this acclimation, in situ photosynthetic CO2 uptake remained higher under elevated CO2. Acclimation at elevated CO2 was accompanied by decreases in both Rubisco and total leaf N contents and an increase in LHC content. Elevated CO2 led to a larger increase in LHC/Rubisco in lower canopy leaves than in the uppermost leaf. Acclimation of leaf photosynthesis to elevated CO2 therefore depended on both vertical position within the canopy and the developmental stage. 相似文献
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刘沿江 李雪阳 梁旭昶 刘炎林 程琛 李娟 汤飘飘 齐惠元 卞晓星 何兵 邢睿 李晟 施小刚 杨创明 薛亚东 连新明 阿旺久美 谢然尼玛 宋大昭 肖凌云 吕植 《生物多样性》2019,27(9):919-238
雪豹(Panthera uncia)分布广泛且调查难度较大, 全世界的雪豹研究面临的首要问题是雪豹基础数据的缺乏。本文通过检索1980至2018年已发表的含有中国境内雪豹分布和密度信息的中英文文章共35篇, 从中提取出雪豹的分布与密度信息, 其中含有密度估计的文献18篇。同时, 来自雪豹调查的15位一线成员通过填写表格和问卷的形式提供了28个地块上未发表的雪豹密度调查信息。基于此, 我们逐一分析了各省份已有的雪豹调查现状和存在的调查空缺, 发现雪豹分布调查的两大空白区域主要存在于与吉尔吉斯斯坦接壤的西天山地区和西藏南部的冈底斯-念青唐古拉山山脉和喜马拉雅山脉。相对我国雪豹栖息地总面积, 有过密度估算的面积仅占1.7%, 仍然处于刚刚起步的阶段, 并且已有的密度调查几乎都是在质量较好的雪豹栖息地内进行的。今后除了需要继续努力收集汇总已有的调查结果, 仍然需要在雪豹分布区(特别是空缺区域)内增加调查。 相似文献