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131.
Fonseca Lde S Vieira GB Sobral LF Ribeiro EO Marsico AG 《Memórias do Instituto Oswaldo Cruz》2012,107(1):142-144
The performance of the nitrate reductase assay (NRA) was compared with the proportion method (PM) on Lowenstein-Jensen medium and the BACTEC MGIT960 assay under routine conditions using 160 clinical isolates of Mycobacterium tuberculosis with a high proportion of resistant strains. The mean time to obtain results was 8.8 days and the overall agreements between NRA and PM and NRA and M960 were 95% and 94%, respectively. NRA was easy to perform and represents a useful tool for the rapid screening of drug-resistant M. tuberculosis strains in low-resource countries. 相似文献
132.
Assessing the Viability of Bacterial Species in Drinking Water by Combined Cellular and Molecular Analyses 总被引:1,自引:0,他引:1
The question which bacterial species are present in water and if they are viable is essential for drinking water safety but
also of general relevance in aquatic ecology. To approach this question we combined propidium iodide/SYTO9 staining (“live/dead
staining” indicating membrane integrity), fluorescence-activated cell sorting (FACS) and community fingerprinting for the
analysis of a set of tap water samples. Live/dead staining revealed that about half of the bacteria in the tap water had intact
membranes. Molecular analysis using 16S rRNA and 16S rRNA gene-based single-strand conformation polymorphism (SSCP) fingerprints
and sequencing of drinking water bacteria before and after FACS sorting revealed: (1) the DNA- and RNA-based overall community
structure differed substantially, (2) the community retrieved from RNA and DNA reflected different bacterial species, classified
as 53 phylotypes (with only two common phylotypes), (3) the percentage of phylotpes with intact membranes or damaged cells
were comparable for RNA- and DNA-based analyses, and (4) the retrieved species were primarily of aquatic origin. The pronounced
difference between phylotypes obtained from DNA extracts (dominated by Betaproteobacteria, Bacteroidetes, and Actinobacteria) and from RNA extracts (dominated by Alpha-, Beta-, Gammaproteobacteria, Bacteroidetes, and Cyanobacteria) demonstrate the relevance of concomitant RNA and DNA analyses for drinking water studies. Unexpected was that a comparable
fraction (about 21%) of phylotypes with membrane-injured cells was observed for DNA- and RNA-based analyses, contradicting
the current understanding that RNA-based analyses represent the actively growing fraction of the bacterial community. Overall,
we think that this combined approach provides an interesting tool for a concomitant phylogenetic and viability analysis of
bacterial species of drinking water. 相似文献
133.
The bacterial core communities of bulk water and corresponding biofilms of a more than 20-year-old drinking water network were compared using 16S rRNA single-strand confirmation polymorphism (SSCP) fingerprints based on extracted DNA and RNA. The structure and composition of the bacterial core community in the bulk water was highly similar (>70%) across the city of Braunschweig, Germany, whereas all biofilm samples contained a unique community with no overlapping phylotypes from bulk water. Biofilm samples consisted mainly of Alphaproteobacteria (26% of all phylotypes), Gammaproteobacteria (11%), candidate division TM6 (11%), Chlamydiales (9%), and Betaproteobacteria (9%). The bulk water community consisted primarily of Bacteroidetes (25%), Betaproteobacteria (20%), Actinobacteria (16%), and Alphaproteobacteria (11%). All biofilm communities showed higher relative abundances of single phylotypes and a reduced richness compared to bulk water. Only biofilm communities sampled at nearby sampling points showed similar communities irrespective of support materials. In all of our bulk water studies, the community composition determined from 16S rRNA was completely different from the 16S rRNA gene-based community composition, whereas in biofilms both molecular fractions resulted in community compositions that were similar to each other. We hypothesize that a higher fraction of active bacterial phylotypes and a better protection from oxidative stress in drinking water biofilms are responsible for this higher similarity. 相似文献
134.
Alvarez M Huygens D Díaz LM Villanueva CA Heyser W Boeckx P 《Plant, cell & environment》2012,35(1):126-135
Acid phosphatase (ACP) enzymes are involved in the mobilization of soil phosphorus (P) and polyphosphate accumulated in the fungal tissues of ectomycorrhizal roots, thereby influencing the amounts of P that are stored in the fungus and transferred to the host plant. This study evaluated the effects of ectomycorrhizal morphotype and soil fertility on ACP activity in the extraradical mycelium (ACP(myc)), the mantle (ACP(mantle)) and the Hartig net region (ACP(Hartig)) of ectomycorrhizal Nothofagus obliqua seedlings. ACP activity was quantified in vivo using enzyme-labelled fluorescence-97 (ELF-97) substrate, confocal laser microscopy and digital image processing routines. There was a significant effect of ectomycorrhizal morphotype on ACP(myc), ACP(mantle) and ACP(Hartig), while soil fertility had a significant effect on ACP(myc) and ACP(Hartig). The relative contribution of the mantle and the Hartig net region to the ACP activity on the ectomycorrhizal root was significantly affected by ectomycorrhizal morphotype and soil fertility. A positive correlation between ACP(Hartig) and the shoot P concentration was found, providing evidence that ACP activity at the fungus:root interface is involved in P transfer from the fungus to the host. It is concluded that the spatial distribution of ACP in ectomycorrhizas varies as a function of soil fertility and colonizing fungus. 相似文献
135.
SA Rad HS Zahiri KA Noghabi S Rajaei R Heidari L Mojallali 《World journal of microbiology & biotechnology》2012,28(1):313-321
In this study a comparison was made between type 1 and type 2 isopentenyl diphosphate isomerases (IDI) in improving lycopene
production in Escherichia coli. The corresponding genes of Bacillus licheniformis and the host (i
Bl
and i
Ec
, respectively) were expressed in lycopene producing E. coli strains by pTlyciBl and pTlyciEc plasmids, under the control of tac promoter. The results showed that the overexpression of i
Ec
improved the lycopene production from 33 ± 1 in E. coli Tlyc to 68 ± 3 mg/gDCW in E. coli TlyciEc. In contrast, the expression of i
Bl
increased the lycopene production more efficiently up to 80 ± 9 mg/gDCW in E. coli TlyciBl. The introduction of a heterologous mevalonate pathway to elevate the IPP abundance resulted in a lycopene production up
to 132 ± 5 mg/gDCW with i
Ec
in E. coli TlyciEc-mev and 181 ± 9 mg/gDCW with i
Bl
in E. coli TlyciBl-mev, that is, 4 and 5.6 times respectively. When fructose, mannose, arabinose, and acetate were each used as an auxiliary
substrate with glycerol, lycopene production was inhibited by different extents. Among auxiliary substrates tested, only citrate
was an improving one for lycopene production in all strains with a maximum of 198 ± 3 mg/gDCW in E. coli TlyciBl-mev. It may be concluded that the type 2 IDI performs better than the type 1 in metabolic engineering attempts for isoprenoid
production in E. coli. In addition, the metabolic engineering of citrate pathway seems a promising approach to have more isoprenoid accumulation
in E. coli. 相似文献
136.
JP Souza JG Cecatti SM Haddad MA Parpinelli ML Costa L Katz L Say;Brazilian Network for Surveillance of Severe Maternal Morbidity 《PloS one》2012,7(8):e44129
Objectives
To validate the WHO maternal near-miss criteria and develop a benchmark tool for severe maternal morbidity assessments.Methods
In a multicenter cross-sectional study implemented in 27 referral maternity hospitals in Brazil, a one-year prospective surveillance on severe maternal morbidity and data collection was carried out. Diagnostic accuracy tests were used to assess the validity of the WHO maternal near-miss criteria. Binary logistic regression was used to model the death probability among women with severe maternal complications and benchmark the management of severe maternal morbidity.Results
Of the 82,388 women having deliveries in the participating health facilities, 9,555 women presented pregnancy-related complications, including 140 maternal deaths and 770 maternal near misses. The WHO maternal near-miss criteria were found to be accurate and highly associated with maternal deaths (Positive likelihood ratio 106.8 (95% CI 99.56–114.6)). The maternal severity index (MSI) model was developed and found to able to describe the relationship between life-threatening conditions and mortality (Area under the ROC curve: 0.951 (95% CI 0.909–0.993)).Conclusion
The identification of maternal near-miss cases using the WHO list of pregnancy-related life-threatening conditions was validated. The MSI model can be used as a tool for benchmarking the performance of health services managing women with severe maternal complications and provide case-mix adjustment. 相似文献137.
Air pollution contributes to poor respiratory and cardiovascular health. Susceptible individuals may be advised to mitigate effects of air pollution through actions such as reducing outdoor physical activity on days with high pollution. Our analysis identifies the extent to which susceptible individuals changed activities due to bad air quality. This cross-sectional study included 10,898 adults from the National Health and Nutrition Examination Survey (NHANES) 2007–2010. Participants reported if they did something differently when air quality was bad. Susceptible categories included respiratory conditions, cardiovascular conditions and older age (≥65 years). Analyses accounted for complex survey design; logistic regression models controlled for gender, race, education, smoking, and body mass index. 1305 individuals reported doing something differently (12.0%, 95% confidence interval (CI): 10.9, 13.1). This percentage was 14.2% (95% CI: 11.6, 16.8), 25.1% (95% CI: 21.7, 28.6), and 15.5% (95% CI: 12.2, 18.9) among older adults, those with a respiratory condition, and those with a cardiovascular condition, respectively. In adjusted regression models the following were significantly more likely to have changed activity compared to those who did not belong to any susceptible group: respiratory conditions (adjusted odds ratio (aOR): 2.61, 95% CI: 2.03, 3.35); respiratory and cardiovascular conditions (aOR: 4.36, 95% CI: 2.47, 7.69); respiratory conditions and older age (aOR: 3.83; 95% CI: 2.47, 5.96); or all three groups (aOR: 3.52; 95% CI: (2.33, 5.32). Having cardiovascular conditions alone was not statistically significant. Some individuals, especially those with a respiratory condition, reported changing activities due to poor air quality. However, efforts should continue to educate the public about air quality and health. 相似文献
138.
139.
D Coggon G Ntani KT Palmer VE Felli R Harari LH Barrero SA Felknor D Gimeno A Cattrell C Serra M Bonzini E Solidaki E Merisalu RR Habib F Sadeghian M Kadir SS Warnakulasuriya K Matsudaira B Nyantumbu MR Sim H Harcombe K Cox MH Marziale LM Sarquis F Harari R Freire N Harari MV Monroy LA Quintana M Rojas EJ Salazar Vega EC Harris S Vargas-Prada JM Martinez G Delclos FG Benavides M Carugno MM Ferrario AC Pesatori L Chatzi P Bitsios M Kogevinas K Oha T Sirk A Sadeghian RJ Peiris-John N Sathiakumar 《PloS one》2012,7(7):e39820
Background
The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.Methods/Principal Findings
A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI).Conclusions/Significance
The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively. 相似文献140.
K Zibara R Hamdan L Dib S Sindet-Pedersen M Kharfan-Dabaja A Bazarbachi M El-Sabban 《PloS one》2012,7(7):e40140
Hematopoietic stem cells (HSC) derived from cord blood (CB), bone marrow (BM), or mobilized peripheral blood (PBSC) can differentiate into multiple lineages such as lymphoid, myeloid, erythroid cells and platelets. The local microenvironment is critical to the differentiation of HSCs and to the preservation of their phenotype in vivo. This microenvironment comprises a physical support supplied by the organ matrix as well as tissue specific cytokines, chemokines and growth factors. We investigated the effects of acellular bovine bone marrow extracts (BME) on HSC in vitro and in vivo. We observed a significant increase in the number of myeloid and erythroid colonies in CB mononuclear cells (MNC) or CB CD34+ cells cultured in methylcellulose media supplemented with BME. Similarly, in xeno-transplantation experiments, pretreatment with BME during ex-vivo culture of HSCs induced a significant increase in HSC engraftment in vivo. Indeed, we observed both an increase in the number of differentiated myeloid, lymphoid and erythroid cells and an acceleration of engraftment. These results were obtained using CB MNCs, BM MNCs or CD34(+) cells, transplanted in immuno-compromised mice (NOD/SCID or NSG). These findings establish the basis for exploring the use of BME in the expansion of CB HSC prior to HSC Transplantation. This study stresses the importance of the mechanical structure and soluble mediators present in the surrounding niche for the proper activity and differentiation of stem cells. 相似文献