Influence of culture conditions and medium composition on the production of antibacterial compounds by marine Serratia sp. WPRA3

This study was undertaken to investigate the influence of culture conditions and medium components on production of antibacterial compounds by Serratia sp. WPRA3 (JX020764) which was isolated from marine water of Port Dickson, Malaysia. Biochemical, morphological, and molecular characteristics suggested that the isolate is a new candidate of the Serratia sp. The isolate showed strong antimicrobial activity against fungi, Gram-negative and Gram-positive bacteria. This bacterium exhibited optimum antibacterial compounds production at 28°C, pH 7 and 200 rev/min aeration during 72 h of incubation period. Highest antibacterial activity was obtained when sodium chloride (2%), yeast extract (0.5%), and glucose concentration (0.75%) were used as salt, nitrogen, and carbon sources respectively. Different active fractions were obtained by Thin-Layer Chromatography (TLC) and Flash Column Chromatography (FCC) from ethyl acetate crude extracts namely OCE and RCE in different culture conditions, OCE (pH 5, 200 rev/min) and RCE (pH 7/without aeration). In conclusion, the results suggested different culture conditions have a significant impact on the types of secondary metabolites produced by the bacterium.     

Genetic diversity of <Emphasis Type="Italic">Pistacia khinjuk</Emphasis> Stocks. using RAPD markers and leaf morphological characters

The aim of this research was to study the genetic diversity of Pistacia khinjuk Stocks. and also to reveal the genetic relationships. Leaf morphological characters of 16 genotypes together with Randomly Amplified Polymorphic DNA (RAPD) marker data were used for this purpose. Leaf morphological characters were used for factor analysis, which determined four main factors. Grouping of genotypes by these factors was performed by Ward’s method. Fifteen primers produced a total of 146 fragments, with an average of 9.73 fragments per primer, of which 129 were polymorphic. The unweighted pair group method based on arithmetic average (UPGMA) analysis was performed on Jaccard’s similarity coefficient matrix. According to RAPD data, genotypes were separated into three groups. The first contained the genotypes with round leaflets. Genotypes with three lanceolate leaflets were located in the second and third groups, respectively. This study revealed that high diversity exists among genotypes of P. khinjuk, like in P. vera. Also it could be postulated that genotypes of P. khinjuk with oblique and lanceolate leaflets are probably descendents of the genotypes with acuminate and roundish leaflets.     

Superoxide dismutase A antigens derived from molecular analysis of sarcoidosis granulomas elicit systemic Th-1 immune responses

Background

Sarcoidosis is an idiopathic granulomatous disease with pathologic and immunologic features similar to tuberculosis. Routine histologic staining and culture fail to identify infectious agents. An alternative means for investigating a role of infectious agents in human pathogenesis involves molecular analysis of pathologic tissues for microbial nucleic acids, as well as recognition of microbial antigens by the host immune system. Molecular analysis for superoxide dismutase A (sodA) allows speciation of mycobacteria. SodA is an abundantly secreted virulence factor that generates cellular immune responses in infected hosts. The purpose of this study is to investigate if target antigens of the sarcoidosis immune response can be identified by molecular analysis of sarcoidosis granulomas.

Methods

We detected sodA amplicons in 12 of 17 sarcoidosis specimens, compared to 2 of 16 controls (p = 0.001, two-tailed Fisher''s exact test), and 3 of 3 tuberculosis specimens (p = 0.54). Analysis of the amplicons revealed sequences identical to M. tuberculosis (MTB) complex, as well as sequences which were genetically divergent. Using peripheral blood mononuclear cells (PBMC) from 12 of the 17 sarcoidosis subjects, we performed enzyme-linked immunospot assay (ELISPOT) to assess for immune recognition of MTB sodA peptides, along with PBMC from 26 PPD- healthy volunteers, and 11 latent tuberculosis subjects.

Results

Six of 12 sarcoidosis subjects recognized the sodA peptides, compared to one of 26 PPD- controls (p = 0.002), and 6/11 PPD+ subjects (p = .68). Overall, 10 of the 12 sarcoidosis subjects from whom we obtained PBMC and archival tissue possessed molecular or immunologic evidence for sodA.

Conclusion

Dual molecular and immunologic analysis increases the ability to find infectious antigens. The detection of Th-1 immune responses to sodA peptides derived from molecular analysis of sarcoidosis granulomas reveals that these are among the target antigens contributing to sarcoidosis granulomatous inflammation.     

Persian shallot, <Emphasis Type="Italic">Allium hirtifolium</Emphasis> Boiss,induced apoptosis in human hepatocellular carcinoma cells

This study investigated the potential of Persian shallot extract as an anticancer agent in HepG2 tumor cell line, an in vitro human hepatoma cancer model system. The inhibitory effect of Persian shallot on the growth of HepG2 cells was measured by MTT assay. To explore the underlying mechanism of cell growth inhibition of Persian shallot, the activity of Persian shallot in inducing apoptosis was investigated through the detection of annexin V signal by flow cytometry and expression of some apoptosis related genes such p21, p53, puma, caspase-8 family-Bcl-2 proteins like bid, bim, bcl-2 and bax were measured by real-time PCR in HepG2 cells. Persian shallot extract inhibited the growth of HepG2 cells in a dose-dependent manner. The IC₅₀ value (inhibiting cell growth by 50%) was 149 μg/ml. The results of real-time PCR revealed a significant up-regulation of bid, bim, caspase-8, puma, p53, p21 and bax genes and a significant downregulation of bcl-2 gene in HepG2 cells treated with Persian shallot extract significantly. Therefore, this is the first report on an increased expression of bid, bim, caspase-8, puma, p53, p21 and bax genes and down regulation of bcl-2 gene indicating that the Persian shallot extract possibly induced the process of cell death through the intrinsic and extrinsic apoptosis pathways and triggers the programmed cell death in HepG2 tumor cell lines by modulating the expression of pro-/anti-apoptotic genes. Furthermore, we showed that Persian shallot extract increased annexin V signal and expression, resulting in apoptotic cell death of HepG2 cells after 24 h treatment. Therefore, according to the results of this study, the Persian shallot extract could be considered as a potential candidate for production of drug for the prevention or treatment of human hepatoma.     

Isoproterenol-induced mortality and cardiac lipids of aspirin-pretreated rats with various fat intakes

The effect of altering cardiac concentrations of precursors and inhibitors of prostaglandin synthesis by varying fat intake was determined in rats injected with the cardiotoxic drug isoproterenol, following pretreatment with aspirin or potassium phosphate buffer solution. Prior to injection, four groups of rats were fed either a low-fat diet (3.7 energy percent coconut oil 3.7 energy percent safflower oil) or a high-fat diet (3.7 energy percent safflower oil-36.4 energy percent coconut oil mixture or 40.1 energy percent safflower oil.) Mortality as well as fatty acid composition of cardiac lipids changed in response to altered kinds and amounts of fats. Mortality and cardiac C20:4/C22:6 ratio were lowered by feeding 3.7 energy percent coconut oil, and increased by feeding 40.1 energy percent safflower oil. Aspirin reduced mortality in rats fed 40.1 energy percent safflower oil, but not in rats fed other diets. Results suggest that dietary manipulations which increase tissue content of polyunsaturated fatty acids of the n-6 type relative to those of the n-3 type may increase sensitivity to isoproterenol, and that effectiveness of aspirin in reducing isoproterenol-induced mortality depends upon the n-6/n-3 ratio of cardiac fatty acids.     

Probing the Architecture of a Multi-PDZ Domain Protein: Structure of PDZK1 in Solution

1. Download high-res image (158KB)
2. Download full-size image

     

Increased Duration of Paid Maternity Leave Lowers Infant Mortality in Low- and Middle-Income Countries: A Quasi-Experimental Study

Background

Maternity leave reduces neonatal and infant mortality rates in high-income countries. However, the impact of maternity leave on infant health has not been rigorously evaluated in low- and middle-income countries (LMICs). In this study, we utilized a difference-in-differences approach to evaluate whether paid maternity leave policies affect infant mortality in LMICs.

Methods and Findings

We used birth history data collected via the Demographic and Health Surveys to assemble a panel of approximately 300,000 live births in 20 countries from 2000 to 2008; these observational data were merged with longitudinal information on the duration of paid maternity leave provided by each country. We estimated the effect of an increase in maternity leave in the prior year on the probability of infant (<1 y), neonatal (<28 d), and post-neonatal (between 28 d and 1 y after birth) mortality. Fixed effects for country and year were included to control for, respectively, unobserved time-invariant confounders that varied across countries and temporal trends in mortality that were shared across countries. Average rates of infant, neonatal, and post-neonatal mortality over the study period were 55.2, 30.7, and 23.0 per 1,000 live births, respectively. Each additional month of paid maternity was associated with 7.9 fewer infant deaths per 1,000 live births (95% CI 3.7, 12.0), reflecting a 13% relative reduction. Reductions in infant mortality associated with increases in the duration of paid maternity leave were concentrated in the post-neonatal period. Estimates were robust to adjustment for individual, household, and country-level characteristics, although there may be residual confounding by unmeasured time-varying confounders, such as coincident policy changes.

Conclusions

More generous paid maternity leave policies represent a potential instrument for facilitating early-life interventions and reducing infant mortality in LMICs and warrant further discussion in the post-2015 sustainable development agenda. From a policy planning perspective, further work is needed to elucidate the mechanisms that explain the benefits of paid maternity leave for infant mortality.     

Trace Element Level in Different Tissues of <Emphasis Type="Italic">Rutilus frisii kutum</Emphasis> Collected from Tajan River,Iran

Tajan River is among the most significant rivers of the Caspian Sea water basin. In this study, the concentration of Cr, Cu, Fe, Mn, Ni, Pb, Cd, and Zn were determined in brain, heart, liver, gill, bile, and muscle of Rutilus frisii kutum which has great economic value in the Mazandaran state. Trace element levels in fish samples were analyzed by means of atomic absorption spectrometry. Nearly all non-essential metals levels (Ni, Pb, Cd) detected in tissues were higher than limits for fish proposed by FAO/WHO, EU, and TFC. Generally, non-essential metals (Ni, Pb) were so much higher in muscle than the essential metals (Cu, Zn, and Mn) except Fe, which was higher than other metals in nearly all parts, except in gills. Fe distribution pattern in tissues was in order of heart > brain > liver > muscle > bile > gill. Distribution patterns of metal concentrations in the muscle of fish as a main edible part followed the sequence: Fe > Pb > Ni > Cu > Mn > Zn > Cd.     

Electrohydrodynamic mortality of insects: a plausible mechanism

 An electrohydrodynamic (EHD) system with a point-to-plane electrode, which produced air ions within a strong electric field, was used to study mortalities of pupae, larvae, and adults of Tribolium confusum (TC) and larvae of Plodia interpunctella (PI). The treatments included a neutral air stream, negative ions, positive ions, and the air stream superimposed with ions of either polarity. The negative ions caused the maximum mortality in TC pupae and PI larvae whereas the TC adults were least affected, but the negative ion flux was higher than the positive one at the constant high voltage of the power supply used in the present experiments. The differences in the mean mortalities of the treatment groups were highly significant (P<0.0001). Mortality was primarily attributed to the body fluid losses caused by the electric wind of the EHD system. Mortality and weight loss relationships were linear with negative slopes (r ²=0.52, and r ²=0.98 for TC and PI, respectively). The superimposition of the air stream with either positive or negative ion fluxes increased the survival fractions compared with those of the ion fluxes alone. Received: 27 May 1996 / Accepted: 9 September 1996