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11.
Moreira R Pinho JR Fares J Oba IT Cardoso MR Saraceni CP Granato C 《Canadian journal of microbiology》2003,49(8):503-507
The aims of this study were to (i) evaluate the prevalence and the incidence of hepatitis C virus (HCV) infection in hemodialysis patients in two different centers in S?o Paulo (Brazil), (ii) determine the time required to detect HCV infection among these patients by serology or PCR, (iii) establish the importance of alanine aminotransferase determination as a marker of HCV infection, and (iv) identify the HCV genotypes in this population. Serum samples were collected monthly for 1 year from 281 patients admitted to hospital for hemodialysis. Out of 281 patients, 41 patients (14.6%) were HCV positive; six patients seroconverted during this study (incidence = 3.1/1000 person-month). In 1.8% (5/281) of cases, RNA was detected before the appearance of antibodies (up to 5 months), and in 1.1% (3/281) of cases, RNA was the unique marker of HCV infection. The genotypes found were 1a, 1b, 3a, and 4a. The presence of genotype 4a is noteworthy, since it is a rare genotype in Brazil. These data pointed out the high prevalence and incidence of HCV infection at hemodialysis centers in Brazil and showed that routine PCR is fundamental for improving the detection of HCV carriers among patients undergoing hemodialysis. 相似文献
12.
We discuss in this review recent studies using the worm Caenorhabditis elegans to decipher endocytic trafficking in a multicellular organism. Recent advances, including in vivo assay systems, new genetic screens, comparative functional analysis of conserved proteins, and RNA-mediated interference (RNAi) in C. elegans, are being used to study the functions of known membrane trafficking factors and to identify new ones. The ability to monitor endocytosis in vivo in worms allows one to test current endocytosis models and to demonstrate the physiological significance of factors identified by genetic and biochemical methods. The available human genome sequence facilitates comparative studies where human homologs of new factors identified in C. elegans can be quickly assayed for similar function using traditional cell biological methods in mammalian cell systems. New studies in C. elegans have used a combination of these techniques to reveal novel metazoan-specific trafficking factors required for endocytosis. Many more metazoan-specific trafficking factors and insights into the mechanisms of endocytosis are likely to be uncovered by analysis in C. elegans . 相似文献
13.
Victoria?BrankinEmail author Marcus?RP?Mitchell Bob?Webb Morag?G?Hunter 《Reproductive biology and endocrinology : RB&E》2003,1(1):55
Oocyte control of granulosa and theca cell function may be mediated by several growth factors via a local feedback loop(s)
between these cell types. This study examined both the role of oocyte-secreted factors on granulosa and thecal cells, cultured
independently and in co-culture, and the effect of stem cell factor (SCF); a granulosa cell derived peptide that appears to
have multiple roles in follicle development. Granulosa and theca cells were isolated from 2–6 mm healthy follicles of mature
porcine ovaries and cultured under serum-free conditions, supplemented with: 100 ng/ml LR3 IGF-1, 10 ng/ml insulin, 100 ng/ml
testosterone, 0–10 ng/ml SCF, 1 ng/ml FSH (granulosa), 0.01 ng/ml LH (theca) or 1 ng/ml FSH and 0.01 ng/ml LH (co-culture)
and with/without oocyte conditioned medium (OCM) or 5 oocytes. Cells were cultured in 96 well plates for 144 h, after which
viable cell numbers were determined. Medium was replaced every 48 h and spent medium analysed for steroids. 相似文献
14.
Sara Charmsaz Kirrilee Beckett Fiona M. Smith Claudia Bruedigam Andrew S. Moore Fares Al-Ejeh Steven W. Lane Andrew W. Boyd 《PloS one》2015,10(6)
Members of the Eph family of receptor tyrosine kinases and their membrane bound ephrin ligands have been shown to play critical roles in many developmental processes and more recently have been implicated in both normal and pathological processes in post-embryonic tissues. In particular, expression studies of Eph receptors and limited functional studies have demonstrated a role for the Eph/ephrin system in hematopoiesis and leukemogenesis. In particular, EphA2 was reported on hematopoietic stem cells and stromal cells. There are also reports of EphA2 expression in many different types of malignancies including leukemia, however there is a lack of knowledge in understanding the role of EphA2 in hematopoiesis and leukemogenesis. We explored the role of EphA2 in hematopoiesis by analyzing wild type and EphA2 knockout mice. Mature, differentiated cells, progenitors and hematopoietic stem cells derived from knockout and control mice were analyzed and no significant abnormality was detected. These studies showed that EphA2 does not have an obligatory role in normal hematopoiesis. Comparative studies using EphA2-negative MLL-AF9 leukemias derived from EphA2-knockout animals showed that there was no detectable functional role for EphA2 in the initiation or progression of the leukemic process. However, expression of EphA2 in leukemias initiated by MLL-AF9 suggested that this protein might be a possible therapy target in this type of leukemia. We showed that treatment with EphA2 monoclonal antibody IF7 alone had no effect on tumorigenicity and latency of the MLL-AF9 leukemias, while targeting of EphA2 using EphA2 monoclonal antibody with a radioactive payload significantly impaired the leukemic process. Altogether, these results identify EphA2 as a potential radio-therapeutic target in leukemias with MLL translocation. 相似文献
15.
Silvano Fares Elina Oksanen Mika Lännenpää Riitta Julkunen-Tiitto Francesco Loreto 《Photosynthesis research》2010,104(1):61-74
Plants are exposed to increasing levels of tropospheric ozone concentrations. This pollutant penetrates in leaves through
stomata and quickly reacts inside leaves, thus making plants valuable ozone sinks, but at the same time triggers oxidation
processes which lead to leaf injuries. To counteract these negative effects, plants produce an array of antioxidants which
react with ozone and reactive molecules which ozone generates in the leaf tissues. In this study, we measured the effect of
an ozone concentration which is likely to be attained in many areas of the world in the near future (80 ppb) on leaves of
the vertical profile of the widespread agroforestry species Populus nigra. Changes in (1) physiological parameters (photosynthesis and stomatal conductance), (2) ozone uptake, (3) emission of volatile
organic compounds (VOCs, i.e. isoprene, methanol and other oxygenated compounds), (4) concentration of antioxidant surface
compounds, and (5) concentration of phenolic compounds were assessed. The aim was to assess whether the defensive pathways
leading to isoprenoids and phenolics formation were induced when a moderate and chronic increment of ozone is not able to
damage photosynthesis. No visual injuries and minor changes in physiology and ozone uptake were observed. The emission of
isoprene and oxygenated six-carbon (C6) volatiles were inhibited by ozone, whereas methanol emission was increased, especially
in developing leaves. We interpret these results as suggesting an ontogenetic shift in ozone-treated leaves, leading to a
slower development and a faster senescence. Most surface and phenolic compounds showed a declining trend in concentration
from the youngest to the fully expanded leaves. Ozone reduced the concentrations of chlorogenic acid derivatives at the leaf
surface, whereas in total leaf extracts a metabolic shift towards few phenolics with higher antioxidant capacity was observed. 相似文献
16.
Spain AM Peacock AD Istok JD Elshahed MS Najar FZ Roe BA White DC Krumholz LR 《Applied and environmental microbiology》2007,73(15):4892-4904
Immobilization of uranium in groundwater can be achieved through microbial reduction of U(VI) to U(IV) upon electron donor addition. Microbial community structure was analyzed in ethanol-biostimulated and control sediments from a high-nitrate (>130 mM), low-pH, uranium-contaminated site in Oak Ridge, TN. Analysis of small subunit (SSU) rRNA gene clone libraries and polar lipid fatty acids from sediments revealed that biostimulation resulted in a general decrease in bacterial diversity. Specifically, biostimulation resulted in an increase in the proportion of Betaproteobacteria (10% of total clones in the control sediment versus 50 and 79% in biostimulated sediments) and a decrease in the proportion of Gammaproteobacteria and Acidobacteria. Clone libraries derived from dissimilatory nitrite reductase genes (nirK and nirS) were also dominated by clones related to Betaproteobacteria (98% and 85% of total nirK and nirS clones, respectively). Within the nirK libraries, one clone sequence made up 59 and 76% of sequences from biostimulated sediments but only made up 10% of the control nirK library. Phylogenetic analysis of SSU rRNA and nirK gene sequences from denitrifying pure cultures isolated from the site indicate that all belong to a Castellaniella species; nearly identical sequences also constituted the majority of biostimulated SSU rRNA and nirK clone libraries. Thus, by combining culture-independent with culture-dependent techniques, we were able to link SSU rRNA clone library information with nirK sequence data and conclude that a potentially novel Castellaniella species is important for in situ nitrate removal at this site. 相似文献
17.
Phylogenetic and Metabolic Diversity of Planctomycetes from Anaerobic, Sulfide- and Sulfur-Rich Zodletone Spring, Oklahoma
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Mostafa S. Elshahed Noha H. Youssef Qingwei Luo Fares Z. Najar Bruce A. Roe Tracy M. Sisk Solveig I. Bühring Kai-Uwe Hinrichs Lee R. Krumholz 《Applied microbiology》2007,73(15):4707-4716
We investigated the phylogenetic diversity and metabolic capabilities of members of the phylum Planctomycetes in the anaerobic, sulfide-saturated sediments of a mesophilic spring (Zodletone Spring) in southwestern Oklahoma. Culture-independent analyses of 16S rRNA gene sequences generated using Planctomycetes-biased primer pairs suggested that an extremely diverse community of Planctomycetes is present at the spring. Although sequences that are phylogenetically affiliated with cultured heterotrophic Planctomycetes were identified, the majority of the sequences belonged to several globally distributed, as-yet-uncultured Planctomycetes lineages. Using complex organic media (aqueous extracts of the spring sediments and rumen fluid), we isolated two novel strains that belonged to the Pirellula-Rhodopirellula-Blastopirellula clade within the Planctomycetes. The two strains had identical 16S rRNA gene sequences, and their closest relatives were isolates from Kiel Fjord (Germany), Keauhou Beach (HI), a marine aquarium, and tissues of marine organisms (Aplysina sp. sponges and postlarvae of the giant tiger prawn Penaeus monodon). The closest recognized cultured relative of strain Zi62 was Blastopirellula marina (93.9% sequence similarity). Detailed characterization of strain Zi62 revealed its ability to reduce elemental sulfur to sulfide under anaerobic conditions, as well as its ability to produce acids from sugars; both characteristics may potentially allow strain Zi62 to survive and grow in the anaerobic, sulfide- and sulfur-rich environment at the spring source. Overall, this work indicates that anaerobic metabolic abilities are widely distributed among all major Planctomycetes lineages and suggests carbohydrate fermentation and sulfur reduction as possible mechanisms employed by heterotrophic Planctomycetes for growth and survival under anaerobic conditions. 相似文献
18.
Currently, the identification of groups of amino acid residues that are important in the function, structure, or interaction of a protein can be both costly and prohibitively complex, involving vast numbers of mutagenesis experiments. Here, we present the application of a novel computational method, which identifies the presence of coevolution in a data set, thereby enabling the a priori identification of amino acid residues that play an important role in protein function. We have applied this method to the heat shock protein (Hsp) protein-folding system, studying the network between Hsp70, Hsp90, and Hop (heat shock-organizing protein). Our analysis has identified functional residues within the tetratricopeptide repeat (TPR) 1 and 2A domains in Hop, previously shown to be interacting with Hsp70 and Hsp90, respectively. Further, we have identified significant residues elsewhere in Hop within domains that have been recently proposed as being important for Hop interaction with Hsp70 and/or Hsp90. In addition, several amino acid sites present in groups of coevolution were identified as 3-dimensionally or linearly proximal to functionally important sites or domains. Based on our results, we also investigate a further functional domain within Hop, between TPR1 and TPR2A, which we suggest as being functionally important in the interaction of Hop with both Hsp70 and Hsp90 whether directly or otherwise. Our method has identified all the previously characterized functionally important regions in this system, thereby indicating the power of this method in the a priori identification of important regions for site-directed mutagenesis studies. 相似文献
19.
Background
Mucolipidosis Type IV is currently characterized as a lysosomal storage disorder with defects that include corneal clouding, achlorhydria and psychomotor retardation. MCOLN1, the gene responsible for this disease, encodes the protein mucolipin-1 that belongs to the "Transient Receptor Potential" family of proteins and has been shown to function as a non-selective cation channel whose activity is modulated by pH. Two cell biological defects that have been described in MLIV fibroblasts are a hyperacidification of lysosomes and a delay in the exit of lipids from lysosomes. 相似文献20.
Lin Sen Mario A Fares Bo Liang Lei Gao Bo Wang Ting Wang Ying-Juan Su 《Biology direct》2011,6(1):1-19