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1.
Cristian Koepfli Priscila T. Rodrigues Tiago Antao Pamela Orjuela-Sánchez Peter Van den Eede Dionicia Gamboa Nguyen van Hong Jorge Bendezu Annette Erhart Céline Barnadas Arsène Ratsimbasoa Didier Menard Carlo Severini Michela Menegon Bakri Y. M. Nour Nadira Karunaweera Ivo Mueller Marcelo U. Ferreira Ingrid Felger 《PLoS neglected tropical diseases》2015,9(6)
Plasmodium vivax is the geographically most widespread human malaria parasite. To analyze patterns of microsatellite diversity and population structure across countries of different transmission intensity, genotyping data from 11 microsatellite markers was either generated or compiled from 841 isolates from four continents collected in 1999–2008. Diversity was highest in South-East Asia (mean allelic richness 10.0–12.8), intermediate in the South Pacific (8.1–9.9) Madagascar and Sudan (7.9–8.4), and lowest in South America and Central Asia (5.5–7.2). A reduced panel of only 3 markers was sufficient to identify approx. 90% of all haplotypes in South Pacific, African and SE-Asian populations, but only 60–80% in Latin American populations, suggesting that typing of 2–6 markers, depending on the level of endemicity, is sufficient for epidemiological studies. Clustering analysis showed distinct clusters in Peru and Brazil, but little sub-structuring was observed within Africa, SE-Asia or the South Pacific. Isolates from Uzbekistan were exceptional, as a near-clonal parasite population was observed that was clearly separated from all other populations (F
ST>0.2). Outside Central Asia F
ST values were highest (0.11–0.16) between South American and all other populations, and lowest (0.04–0.07) between populations from South-East Asia and the South Pacific. These comparisons between P. vivax populations from four continents indicated that not only transmission intensity, but also geographical isolation affect diversity and population structure. However, the high effective population size results in slow changes of these parameters. This persistency must be taken into account when assessing the impact of control programs on the genetic structure of parasite populations. 相似文献
2.
Dionicia Gamboa Mei-Fong Ho Jorge Bendezu Katherine Torres Peter L. Chiodini John W. Barnwell Sandra Incardona Mark Perkins David Bell James McCarthy Qin Cheng 《PloS one》2010,5(1)
Background
Malaria rapid diagnostic tests (RDTs) offer significant potential to improve the diagnosis of malaria, and are playing an increasing role in malaria case management, control and elimination. Peru, along with other South American countries, is moving to introduce malaria RDTs as components of malaria control programmes supported by the Global Fund for AIDS, TB and malaria. The selection of the most suitable malaria RDTs is critical to the success of the programmes.Methods
Eight of nine microscopy positive P. falciparum samples collected in Iquitos, Peru tested negative or weak positive using HRP2-detecting RDTs. These samples were tested for the presence of pfhrp2 and pfhrp3 and their flanking genes by PCR, as well as the presence of HRP proteins by ELISA. To investigate for geographic extent of HRP-deleted parasites and their temporal occurrence a retrospective study was undertaken on 148 microscopy positive P. falciparum samples collected in different areas of the Amazon region of Peru.Findings
Eight of the nine isolates lacked the pfhrp2 and/or pfhrp3 genes and one or both flanking genes, and the absence of HRP was confirmed by ELISA. The retrospective study showed that 61 (41%) and 103 (70%) of the 148 samples lacked the pfhrp2 or pfhrp3 genes respectively, with 32 (21.6%) samples lacking both hrp genes.Conclusions
This is the first documentation of P. falciparum field isolates lacking pfhrp2 and/or pfhrp3. The high frequency and wide distribution of different parasites lacking pfhrp2 and/or pfhrp3 in widely dispersed areas in the Peruvian Amazon implies that malaria RDTs targeting HRP2 will fail to detect a high proportion of P. falciparum in malaria-endemic areas of Peru and should not be used. RDTs detecting parasite LDH or aldolase and quality microscopy should be use for malaria diagnosis in this region. There is an urgent need for investigation of the abundance and geographic distribution of these parasites in Peru and neighbouring countries. 相似文献3.
Resistance to Meloidogyne arenaria in the peanut cultivar COAN is inherited as a single, dominant gene. The mechanism of resistance to M. arenaria in COAN was evaluated in three experiments. In the first experiment the number of second-stage juveniles (J2) of M. arenaria penetrating roots of the susceptible cultivar Florunner was higher than the number of J2 penetrating roots of the resistant peanut cultivar COAN (P < 0.05). In a second experiment it was determined that the root size and number of potential infection courts (root tips) were similar for the two peanut cultivars. The number of nematodes emigrating from roots of COAN after penetration was greater than emigrated from roots of Florunner (P < 0.05). Necrotic host tissue was rarely observed in roots of COAN infected with M. arenaria, suggesting that resistance to M. arenaria does not involve a necrotic, hypersensitive response. Most of the J2 observed in roots of COAN were restricted to the cortical tissue, with only 1 of 90 J2 observed being associated with the vascular cylinder, whereas in Florunner >70% of the J2 were associated with vascular tissues. Resistance in COAN may be due to constitutive factors in the roots. 相似文献
4.
Two molecular protocols for the identification of mussel and scallop have been developed using specific primers targeting
the mitochondrial 16S ribosomal DNA gene and the nuclear 18S ribosomal DNA gene. Primers for the mitochondrial 16S ribosomal
DNA gene in multiplex polymerase chain reaction (PCR) protocols yielded diagnostic DNA fragments for the mussels Mytilus edulis, Mytilus galloprovincialis, and the hybrid Mytilus edulis/galloprovincialis (335 bp), the king scallop Pecten maximus (382 bp) and the black scallop Mimachlamys varia (398 bp). DNA from the queen scallop Aequipecten opercularis showed no consistent PCR amplification of the 16S rDNA gene. Primers for the nuclear 18S rDNA gene in standard PCR protocols
yielded similar-sized, diagnostic DNA fragments (approx. 190 bp) for the mussels Mytilus edulis, Mytilus galloprovincialis, and the hybrid Mytilus edulis/galloprovincialis, the king scallop Pecten maximus, the black scallop Mimachlamys varia, and the queen scallop Aequipecten opercularis. Both protocols have been tested with Mytilus spp., P. maximus, and 6 other bivalve species from a wide range of locations in Irish and European waters. Cross reaction of the specific
primers with DNA template from any of the 6 other bivalve species was not observed. Rapid DNA extraction using FTA Card technology
and the16S rDNA primers allowed for the detection of at least 10 mussel larvae in a subsample of natural plankton. 相似文献
5.
van den Ent F Leaver M Bendezu F Errington J de Boer P Löwe J 《Molecular microbiology》2006,62(6):1631-1642
The bacterial actin homologue MreB forms helical filaments in the cytoplasm of rod-shaped bacteria where it helps maintain the shape of the cell. MreB is co-transcribed with mreC that encodes a bitopic membrane protein with a major periplasmic domain. Like MreB, MreC is localized in a helical pattern and might be involved in the spatial organization of the peptidoglycan synthesis machinery. Here, we present the structure of the major, periplasmic part of MreC from Listeria monocytogenes at 2.5 A resolution. MreC forms a dimer through an intimate contact along an N-terminal alpha-helix that connects the transmembrane region with two C-terminal beta-domains. The translational relationship between the molecules enables, in principle, filament formation. One of the beta-domains shows structural similarity to the chymotrypsin family of proteins and possesses a highly conserved Thr Ser dipeptide. Unexpectedly, mutagenesis studies show that the dipeptide is dispensable for maintaining cell shape and viability in both Escherichia coil and Bacillus subtilis. Bacterial two-hybrid experiments reveal that MreC Interacts with high-molecular-weight penicillin-binding proteins (PBPs), rather than with low-molecular-weight endo- and carboxypeptidases, indicating that MreC might act as a scaffold to which the murein synthases are recruited in order to spatially organize the synthesis of new cell wall material. Deletion analyses indicate which domains of B. subtilis MreC are required for interaction with MreD as well as with the PBPs. 相似文献
6.
Randi T Garmo Steinar Waage Ståle Sviland Britt IF Henriksen Olav Østerås Olav Reksen 《Acta veterinaria Scandinavica》2010,52(1):11
Background
The objectives of this study were to investigate whether there were differences between Norwegian Red cows in conventional and organic farming with respect to reproductive performance, udder health, and antibiotic resistance in udder pathogens. 相似文献7.
Pramod Kumar Yadav Gurmit Singh Satendra Singh Budhayash Gautam Esmaiel IF Saad 《Bioinformation》2012,8(14):664-672
The emergence of multidrug-resistant strain of community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) strain
has highlighted the urgent need for the alternative and effective therapeutic approach to combat the menace of this nosocomial
pathogen. In the present work novel potential therapeutic drug targets have been identified through the metabolic pathways
analysis. All the gene products involved in different metabolic pathways of CA-MRSA in KEGG database were searched against
the proteome of Homo sapiens using the BLASTp program and the threshold of E-value was set to as 0.001. After database
searching, 152 putative targets were identified. Among all 152 putative targets, 39 genes encoding for putative targets were
identified as the essential genes from the DEG database which are indispensable for the survival of CA-MRSA. After extensive
literature review, 7 targets were identified as potential therapeutic drug target. These targets are Fructose-bisphosphate aldolase,
Phosphoglyceromutase, Purine nucleoside phosphorylase, Uridylate kinase, Tryptophan synthase subunit beta, Acetate kinase and
UDP-N-acetylglucosamine 1-carboxyvinyltransferase. Except Uridylate kinase all the identified targets were involved in more than
one metabolic pathways of CA-MRSA which underlines the importance of drug targets. These potential therapeutic drug targets
can be exploited for the discovery of novel inhibitors for CA-MRSA using the structure based drug design (SBDD) strategy. 相似文献
8.
In the development of multicellularity, signaling proteins has played a very important role. Among them, RAS family is one of the
most widely studied protein family. However, evolutionary analysis has been carried out mainly on super family level leaving sub
family information in scanty. Thus, a subfamily evolutionary study on RAS evolutionary expansion is imperative as it will aid in
better drug designing against dreadful diseases like Cancer and other developmental diseases. The present study was aimed to
understand RAS evolution on both holistic as well as reductive level. All human RAS family genes and protein were subjected to
BLAST tools to find orthologs and paralogs with different parameters followed by phylogenetic tree generation. Our results clearly
showed that H-RAS is the most primitive RAS in higher eukaryotes and then diverged into other RAS family members due to
different gene modification events. Furthermore, a site specific selection pressure analysis was carried out using SELECTON server
which showed that H-RAS, M-RAS and N-RAS are evolving faster than K-RAS and R-RAS. Thus, the results ascertain a new
ground to cancer biologists to exploit negatively selected K-RAS and R-RAS as potent drug targets in cancer therapeutics. 相似文献
9.
Background
Breast cancer survivors, particularly those treated with chemotherapy, are at significantly increased risk for long-term cognitive and neurobiologic impairments. These deficits tend to involve skills that are subserved by distributed brain networks. Additionally, neuroimaging studies have shown a diffuse pattern of brain structure changes in chemotherapy-treated breast cancer survivors that might impact large-scale brain networks.Methods
We therefore applied graph theoretical analysis to compare the gray matter structural networks of female breast cancer survivors with a history of chemotherapy treatment and healthy age and education matched female controls.Results
Results revealed reduced clustering coefficient and small-world index in the brain network of the breast cancer patients across a range of network densities. In addition, the network of the breast cancer group had less highly interactive nodes and reduced degree/centrality in the frontotemporal regions compared to controls, which may help explain the common impairments of memory and executive functioning among these patients.Conclusions
These results suggest that breast cancer and chemotherapy may decrease regional connectivity as well as global network organization and integration, reducing efficiency of the network. To our knowledge, this is the first report of altered large-scale brain networks associated with breast cancer and chemotherapy. 相似文献10.
Sandra Morales Ruiz Jorge Bendezu Ricardo Choque Guevara Ricardo Montesinos David Requena Luz Choque Moreau Ángela Montalván Ávalos Manolo Fernández-Díaz 《BMC veterinary research》2018,14(1):411