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991.
Dang Thi Minh Ha Nguyen Thi Ngoc Lan Marcel Wolbers Tran Ngoc Duong Nguyen Dang Quang Tran Thi Van Thinh Le Thi Hong Ngoc Nguyen Thi Ngoc Anh Tran Van Quyet Nguyen Thi Bich Tuyen Vo Thi Ha Jeremy Day Hoang Thi Thanh Hang Vo Sy Kiet Nguyen Thi Nho Dai Viet Hoa Nguyen Huy Dung Nguyen Huu Lan Jeremy Farrar Maxine Caws 《PloS one》2009,4(12)
MODS is a novel liquid culture based technique that has been shown to be effective and rapid for early diagnosis of tuberculosis (TB). We evaluated the MODS assay for diagnosis of TB in children in Viet Nam. 217 consecutive samples including sputum (n = 132), gastric fluid (n = 50), CSF (n = 32) and pleural fluid (n = 3) collected from 96 children with suspected TB, were tested by smear, MODS and MGIT. When test results were aggregated by patient, the sensitivity and specificity of smear, MGIT and MODS against “clinical diagnosis” (confirmed and probable groups) as the gold standard were 28.2% and 100%, 42.3% and 100%, 39.7% and 94.4%, respectively. The sensitivity of MGIT and MODS was not significantly different in this analysis (P = 0.5), but MGIT was more sensitive than MODS when analysed on the sample level using a marginal model (P = 0.03). The median time to detection of MODS and MGIT were 8 days and 13 days, respectively, and the time to detection was significantly shorter for MODS in samples where both tests were positive (P<0.001). An analysis of time-dependent sensitivity showed that the detection rates were significantly higher for MODS than for MGIT by day 7 or day 14 (P<0.001 and P = 0.04), respectively. MODS is a rapid and sensitive alternative method for the isolation of M.tuberculosis from children. 相似文献
992.
O. B. Flekhter N. I. Medvedeva G.A. Tolstikov F. Z. Galin M. S. Yunusov Huong Nguen Thi Mai Le Viet Tien I. V. Savinova E. I. Boreko L. P. Titov I. V. Glukhov 《Russian Journal of Bioorganic Chemistry》2009,35(2):233-239
The rare olean-18(19)-ene triterpenoids moradiol and moronic acid were synthesized from betulin, and their antiviral properties were investigated. 相似文献
993.
Suttiprapa S Mulvenna J Huong NT Pearson MS Brindley PJ Laha T Wongkham S Kaewkes S Sripa B Loukas A 《The international journal of biochemistry & cell biology》2009,41(5):1148-1156
The human liver fluke Opisthorchis viverrini is endemic in Thailand, Laos and Cambodia where long standing infection is associated with cancer of the bile ducts, cholangiocarcinoma. Here we describe a cathepsin D-like aspartic protease from the gut and other tissues in O. viverrini. Phylogenetic analysis indicated that Ov-APR-1 is cathepsin D-like, conforming with Clan AA, Family A1 of the MEROPS classification. Ov-APR-1 is expressed in the gut of the mature hermaphroditic parasite, in the reproductive tissues including the testis and immature spermatids, and the developing miracidium within the eggshell. The enzyme was also detected in the excretory/secretory products of cultured adult flukes, indicating a role in host-parasite relationships. A recombinant form of the enzyme expressed in Escherichia coli and refolded from denatured inclusion bodies underwent autocatalytic activation and demonstrated hydrolytic activity against the peptide substrate 7-methoxycoumarin-4-acetyl-GKPILFFRLK(DNP)-D-Arg-amide with a k(cat)/K(m)=1.7 x 10(4)M(-1)s(-1) and a pH optimum around pH 2.5-3.0. The recombinant enzyme digested hemoglobin and bovine serum albumin. Forty-six serum albumin peptides were detected after digestion with recombinant Ov-APR-1 and sequenced. Like many other aspartic proteases, Ov-APR-1 displayed promiscuous preferences for residues accommodated at the key subsites of the binding pocket although hydrophobic (Leu, Ala, Ile), positively charged (Lys) and bulky aromatic (Phe) residues, in that order, were preferred at P1. Similar residues were accommodated at P1' although even less selectivity was exerted at this position. 相似文献
994.
Molecular modeling and dynamics studies of purine nucleoside phosphorylase from Bacteroides fragilis
Ivani Pauli Luis Fernando Saraiva Macedo Timmers Rafael Andrade Caceres Luiz Augusto Basso Diógenes Santiago Santos Walter Filgueira de Azevedo Jr. 《Journal of molecular modeling》2009,15(8):913-922
Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of N-ribosidic bonds of purine nucleosides and deoxynucleosides, except adenosine, to generate ribose 1-phosphate and the purine
base. This work describes for the first time a structural model of PNP from Bacteroides fragilis (Bf). We modeled the complexes of BfPNP with six different ligands in order to determine the structural basis for specificity of these ligands against BfPNP. Comparative analysis of the model of BfPNP and the structure of HsPNP allowed identification of structural features responsible for differences in the computationally determined ligand affinities.
The molecular dynamics (MD) simulation was assessed to evaluate the overall stability of the BfPNP model. The superposition of the final onto the initial minimized structure shows that there are no major conformational
changes from the initial model, which is consistent with the relatively low root mean square deviation (RMSD). The results
indicate that the structure of the model was stable during MD, and does not exhibit loosely structured loop regions or domain
terminals. 相似文献
995.
Maria João Gaspar Ana I. de-Lucas Ricardo Alía Jorge Almiro Pinto Paiva Elena Hidalgo José Louzada Helena Almeida Santiago C. González-Martínez 《Tree Genetics & Genomes》2009,5(4):609-616
The management of a genetic improvement program is based on the knowledge of the genetic parameters and their relationships
to determine the genetic gains. Knowledge of the coefficient of coancestry (θ) is a requirement for efficient progeny testing scheme and for estimating additive variance components for any quantitative
trait. When using open-pollinated families, most authors assume that the seedlings are related as half-sibs, but this is not
always true. Our aim was to estimate a mean value of the coancestry coefficient of the families present in a maritime pine
Pinus pinaster Ait. (maritime or cluster pine) progeny trial originating from seed collected in a clonal seed orchard and to study how deviations
from the standard assumption of θ = 0.125 affect heritability estimations. Five highly polymorphic microsatellite markers were scored in 125 offspring from
a subsample of five families from the progeny trial. The mean value of the coancestry coefficient of the families present
in this progeny trial was 0.130. Differences between the unadjusted and adjusted heritability estimates were more pronounced
in wood density (0.609 and 0.586, respectively) than in diameter (0.166 and 0.154, respectively). We conclude that in the
trial, the associated error in heritability estimates due to the inclusion of full-sibs, when assuming a standard coefficient
of relationship among open-pollinated sibs of 0.250, was low and that this result is robust with respect to the number of
families sampled, given unbiased estimates of average relationship among offspring within sib families. 相似文献
996.
Díaz A Carro S Santiago L Estévez J Guevara C Blanco M Sánchez L Sánchez L López N Cruz D López R Cuetara EB Fuentes JL 《Genetics and molecular biology》2009,32(2):367-372
The analysis of DNA damage by mean of Comet or single cell gel electrophoresis (SCGE) assay has been commonly used to assess genotoxic impact in aquatic animals being able to detect exposure to low concentrations of contaminants in a wide range of species. The aims of this work were 1) to evaluate the usefulness of the Comet to detect DNA strand breakage in dolphin leukocytes, 2) to use the DNA diffusion assay to determine the amount of DNA strand breakage associated with apoptosis or necrosis, and 3) to determine the proportion of DNA strand breakage that was unrelated to apoptosis and necrosis. Significant intra-individual variation was observed in all of the estimates of DNA damage. DNA strand breakage was overestimated because a considerable amount (~29%) of the DNA damage was derived from apoptosis and necrosis. The remaining DNA damage in dolphin leukocytes was caused by factors unrelated to apoptosis and necrosis. These results indicate that the DNA diffusion assay is a complementary tool that can be used together with the Comet assay to assess DNA damage in bottlenose dolphins. 相似文献
997.
Marlène Dreux Viet Loan Dao Thi Judith Fresquet Maryse Guérin Zélie Julia Géraldine Verney David Durantel Fabien Zoulim Dimitri Lavillette Fran?ois-Lo?c Cosset Birke Bartosch 《PLoS pathogens》2009,5(2)
HCV entry into cells is a multi-step and slow process. It is believed that the
initial capture of HCV particles by glycosaminoglycans and/or lipoprotein
receptors is followed by coordinated interactions with the scavenger receptor
class B type I (SR-BI), a major receptor of high-density lipoprotein (HDL), the
CD81 tetraspanin, and the tight junction protein Claudin-1, ultimately leading
to uptake and cellular penetration of HCV via low-pH endosomes.
Several reports have indicated that HDL promotes HCV entry through interaction
with SR-BI. This pathway remains largely elusive, although it was shown that HDL
neither associates with HCV particles nor modulates HCV binding to SR-BI. In
contrast to CD81 and Claudin-1, the importance of SR-BI has only been addressed
indirectly because of lack of cells in which functional complementation assays
with mutant receptors could be performed. Here we identified for the first time
two cell types that supported HCVpp and HCVcc entry upon ectopic SR-BI
expression. Remarkably, the undetectable expression of SR-BI in rat hepatoma
cells allowed unambiguous investigation of human SR-BI functions during HCV
entry. By expressing different SR-BI mutants in either cell line, our results
revealed features of SR-BI intracellular domains that influence HCV infectivity
without affecting receptor binding and stimulation of HCV entry induced by
HDL/SR-BI interaction. Conversely, we identified positions of SR-BI ectodomain
that, by altering HCV binding, inhibit entry. Finally, we characterized
alternative ectodomain determinants that, by reducing SR-BI cholesterol uptake
and efflux functions, abolish HDL-mediated infection-enhancement. Altogether, we
demonstrate that SR-BI is an essential HCV entry factor. Moreover, our results
highlight specific SR-BI determinants required during HCV entry and
physiological lipid transfer functions hijacked by HCV to favor infection. 相似文献
998.
Penélope González-Sampériz Suzanne A.G. Leroy Santiago Fernández María José Gil-García Blas Valero-Garcés 《Review of Palaeobotany and Palynology》2010,162(3):427-37
A palaeobotanical analysis of the Pleistocene floras and vegetation in the Iberian Peninsula shows the existence of patched landscapes with Pinus woodlands, deciduous and mixed forests, parklands (savannah-like), shrublands, steppes and grasslands. Extinctions of Arctotertiary woody taxa are recorded during the Early and Middle Pleistocene, but glacial refugia facilitated the survival of a number of temperate, Mediterranean and Ibero-North African woody angiosperms. The responses of Iberian vegetation to climatic changes during the Pleistocene have been spatially and temporarily complex, including rapid changes of vegetation in parallel to orbital and suborbital variability, and situations of multi-centennial resilience or accommodation to climatic changes. Regional characteristics emerged as soon as for the Middle Pleistocene, if not earlier: Ericaceae in the Atlantic coast indicating wetter climate, thermo-mediterranean elements in the south as currently, and broad-leaf trees in the northeastern. Overall, steppe landscapes and open Pinus woodlands prevailed over many continental regions during the cold spells of the Late Pleistocene. The maintenance of a high phytodiversity during the glacials was linked to several refuge zones in the coastal shelves of the Mediterranean and intramountainous valleys. Northern Iberia, especially on coastal areas, was also patched with populations of tree species, and this is not only documented by palaeobotanical data (pollen and charcoal) but also postulated by phylogeographical models. 相似文献
999.
Endogenous short RNAs generated by Dicer 2 and RNA-dependent RNA polymerase 1 regulate mRNAs in the basal fungus Mucor circinelloides 总被引:1,自引:0,他引:1
Francisco Esteban Nicolas Simon Moxon Juan P. de Haro Silvia Calo Igor V. Grigoriev Santiago Torres-Martínez Vincent Moulton Rosa M. Ruiz-Vázquez Tamas Dalmay 《Nucleic acids research》2010,38(16):5535-5541
Endogenous short RNAs (esRNAs) play diverse roles in eukaryotes and usually are produced from double-stranded RNA (dsRNA) by Dicer. esRNAs are grouped into different classes based on biogenesis and function but not all classes are present in all three eukaryotic kingdoms. The esRNA register of fungi is poorly described compared to other eukaryotes and it is not clear what esRNA classes are present in this kingdom and whether they regulate the expression of protein coding genes. However, evidence that some dicer mutant fungi display altered phenotypes suggests that esRNAs play an important role in fungi. Here, we show that the basal fungus Mucor circinelloides produces new classes of esRNAs that map to exons and regulate the expression of many protein coding genes. The largest class of these exonic-siRNAs (ex-siRNAs) are generated by RNA-dependent RNA Polymerase 1 (RdRP1) and dicer-like 2 (DCL2) and target the mRNAs of protein coding genes from which they were produced. Our results expand the range of esRNAs in eukaryotes and reveal a new role for esRNAs in fungi. 相似文献
1000.
Gregory J. Cost Yevgeniy Freyvert Annamaria Vafiadis Yolanda Santiago Jeffrey C. Miller Edward Rebar Trevor N. Collingwood Andrew Snowden Philip D. Gregory 《Biotechnology and bioengineering》2010,105(2):330-340
Anoxic and metabolic stresses in large‐scale cell culture during biopharmaceutical production can induce apoptosis. Strategies designed to ameliorate the problem of apoptosis in cell culture have focused on mRNA knockdown of pro‐apoptotic proteins and over‐expression of anti‐apoptotic ones. Apoptosis in cell culture involves mitochondrial permeabilization by the pro‐apoptotic Bak and Bax proteins; activity of either protein is sufficient to permit apoptosis. We demonstrate here the complete and permanent elimination of both the Bak and Bax proteins in combination in Chinese hamster ovary (CHO) cells using zinc‐finger nuclease‐mediated gene disruption. Zinc‐finger nuclease cleavage of BAX and BAK followed by inaccurate DNA repair resulted in knockout of both genes. Cells lacking Bax and Bak grow normally but fail to activate caspases in response to apoptotic stimuli. When grown using scale‐down systems under conditions that mimic growth in large‐scale bioreactors they are significantly more resistant to apoptosis induced by starvation, staurosporine, and sodium butyrate. When grown under starvation conditions, BAX‐ and BAK‐deleted cells produce two‐ to fivefold more IgG than wild‐type CHO cells. Under normal growth conditions in suspension culture in shake flasks, double‐knockout cultures achieve equal or higher cell densities than unmodified wild‐type cultures and reach viable cell densities relevant for large‐scale industrial protein production. Biotechnol. Bioeng. 2010; 105: 330–340. © 2009 Wiley Periodicals, Inc. 相似文献