A shift in the Hepatitis C virus genotype dominance in blood donor samples from Thailand

Hepatitis C virus (HCV) can be classified into six major genotypes. The HCV genotypes variability accounts for its geographical distribution, its responses to treatments and the clinical outcomes. The aim of this study was to determine the distribution of HCV genotypes among volunteer blood donors in Thailand. Samples from 135 anti-HCV positive blood donors were analyzed. HCV RNA and genotyping was carried out using nested polymerase chain reaction (PCR) and genotype-specific primer PCR for a portion of the core region. HCV RNA was detected in 109 samples (80.7%). Genotype analysis demonstrated four different genotypes. The most common was genotype 3a (36.7%), followed by genotype 6 (29.4%), 1a (19.3%), 1b (6.4%) and mixed infection (1.8%). Seven samples were untyped (6.4%) in the present study. In several previous reports, the prevalence found in Thailand was HCV genotypes 3, 1 and 6. The present results show an increasing importance of the genotype 6 in HCV infections. This study has also described for the first time in Thailand mixed infections of HCV genotypes.     

Characterization and Detection of Endolysin Gene from Three Acinetobacter baumannii Bacteriophages Isolated from Sewage Water

Acinetobacter baumannii is an opportunistic pathogen that exists in hospital environments. The emergence of multidrug resistant A. baumannii (MDRAB) has been reported worldwide. It is necessary to find a novel and effective treatment for MDRAB infection. In this study, three bacteriophages, designated as ØABP-01, ØABP-02 and ØABP-04 were selected for analysis. Transmission electron microscopy showed that bacteriophage ØABP-01 belonged to the Podoviridae family and bacteriophage ØABP-02 and ØABP-04 are classified into the family Myoviridae. ØABP-01 had the widest host range. ØABP-01, ØABP-02 and ØABP-04 exhibited a latent period of 15, 20 and 20 min. The burst sizes of the three bacteriophages were 110, 120 and 150 PFU/cell. DNA restriction analysis using EcoRI, HindIII, PstI, SphI, BamHI and SmaI showed different DNA fragment patterns between the three bacteriophages. ØABP-01 and ØABP-04 was positive for the endolysin gene as determined by PCR. In conclusion, bacteriophage ØABP-01 showed broad host-specificity, good lytic activity and a short latency period, making it an appropriate candidate for studying the control and diagnosis associated with MDRAB infections.     

A chalcone with potent inhibiting activity against biofilm formation by nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi), an important human respiratory pathogen, frequently causes biofilm infections. Currently, resistance of bacteria within the biofilm to conventional antimicrobials poses a major obstacle to effective medical treatment on a global scale. Novel agents that are effective against NTHi biofilm are therefore urgently required. In this study, a series of natural and synthetic chalcones with various chemical substituents were evaluated in vitro for their antibiofilm activities against strong biofilm‐forming strains of NTHi. Of the test chalcones, 3‐hydroxychalcone (chalcone 8 ) exhibited the most potent inhibitory activity, its mean minimum biofilm inhibitory concentration (MBIC₅₀) being 16 μg/mL (71.35 μM), or approximately sixfold more active than the reference drug, azithromycin (MBIC₅₀ 419.68 μM). The inhibitory activity of chalcone 8 , which is a chemically modified chalcone, appeared to be superior to those of the natural chalcones tested. Significantly, chalcone 8 inhibited biofilm formation by all studied NTHi strains, indicating that the antibiofilm activities of this compound occur across multiple strong‐biofilm forming NTHi isolates of different clinical origins. According to antimicrobial and growth curve assays, chalcone 8 at concentrations that decreased biofilm formation did not affect growth of NTHi, suggesting the biofilm inhibitory effect of chalcone 8 is non‐antimicrobial. In terms of structure–activity relationship, the possible substituent on the chalcone backbone required for antibiofilm activity is discussed. These findings indicate that 3‐hydroxychalcone (chalcone 8 ) has powerful antibiofilm activity and suggest the potential application of chalcone 8 as a new therapeutic agent for control of NTHi biofilm‐associated infections.     

Estrogen deprivation aggravates intracellular calcium dyshomeostasis in the heart of obese-insulin resistant rats

The incidence of cardiovascular disease and metabolic syndrome increases after the onset of menopause, giving evidence for the vital role of estrogen. Intracellular calcium [Ca²⁺]i regulation plays an important role in the maintenance of left ventricular (LV) contractile function. Although either estrogen deprivation or obesity has been shown to strongly affect the metabolic status and LV function, the effects of estrogen deprivation on the cardiometabolic status and cardiac [Ca ²⁺]i regulation in the obese-insulin resistant condition have never been investigated. Our hypothesis was that estrogen deprivation aggravates LV dysfunction through the increased impairment of [Ca ²⁺]i homeostasis in obese-insulin resistant rats. Female rats were fed on either a high-fat (HFD, 59.28% fat) or normal (ND, 19.77% fat) diet for 13 weeks. Then, rats were divided into sham (HFS and NDS) operated or ovariectomized (HFO and NDO) groups. Six weeks after surgery, metabolic status, LV function and incidence of [Ca ²⁺]i transients were determined. NDO, HFS, and HFO rats had evidence of obese-insulin resistance indicated by increased body weight with hyperinsulinemia and euglycemia. Although NDO, HFS, and HFO rats had markedly reduced %LV fractional shortening, E/A ratio and decreased [Ca ²⁺]i transient amplitude and decay rate, HFO rats had the most severe impairments. These findings indicate that estrogen deprivation had a strong impact on abnormal LV function through [Ca ²⁺]i regulation. In addition, evidence was found that in obese-insulin resistant rats, estrogen deprivation severely aggravates LV dysfunction via increased impairment of [Ca ²⁺]i homeostasis.     

Development of species-specific SCAR markers for identification of three medicinal species of Phyllanthus

Phyllanthus amarus Schum. & Thonn. has been widely used in traditional medicine in Thailand as an antipyretic, a diuretic, to treat liver diseases and viral infections. Two closely related species, P. debilis L. and P. urinaria Klein ex Willd., with different and less effective medicinal properties, are less commonly used. These three species are similar in morphology and often occur in overlapping populations in nature. The latter two species can easily be mistaken for P. amarus and collected for medicinal uses, which can lead to undesirable results. DNA fingerprints of these species were obtained using RAPD-PCR techniques. RAPD markers specific for each species were identified. Primers for highly specific sequence-characterized-amplified-regions (SCAR) were then designed from nucleotide sequences of specific RAPD markers. These primers efficiently amplified SCAR markers of 408, 501 and 319 bp unique to P. amarus, P. debilis and P. urinaria respectively. This method of plant identification was rapid and highly specific when tested against DNA of several closely related species and was able to amplify specific markers from mixed DNA samples.     

Development of species-specific SCAR markers for identification of three medicinal species of Phyllanthus

Phyllanthus amarus Schum.& Thonn.has been widely used in traditional medicine in Thailand as an antipyretic.a diuretic.to treat liver diseases and viml infections.Two closely related species,P. debills L.and P.urinaria KIein ex Willd.,with different and less effective medicinal properties,are less commonly used.These three species are similar in morphology and often Occur in overlapping populations in nature.The latter two species can easily be mistaken for P.amarus and collected for medicinal uses, which can lead to undesirable results.DNA fingerprints of these species were obtained using RAPD-PCR techniques.RAPD markers specific for each species were identified.Primers for highly specific sequence-characterized-amplified-regions (SCAR) were then designed from nucleotide sequences of specific RAPD markers.These primers efficiently amplified SCAR markers of 408,501 and 319 bp unique to P.amarus,P.debilis and P.urinaria respectively.This method of plant identification Was rapid and highly specific when tested against DNA of several closely related species and was able to amplify specific markers from mixed DNA samples.     

Partial nonstructural 3 region analysis of hepatitis C virus genotype 3a

Molecular Biology Reports - The hepatitis C virus (HCV) is a major cause of illness around the world. HCV genotype 3a is the most prevalent genotype in Thailand. Direct-acting antiviral (DAA) drugs...     

Role of rpoS in the development of cell envelope resilience and pressure resistance in stationary-phase Escherichia coli

This work investigated the role of rpoS in the development of increased cell envelope resilience and enhanced pressure resistance in stationary-phase cells of Escherichia coli. Loss of both colony-forming ability and membrane integrity, measured as uptake of propidium iodide (PI), occurred at lower pressures in E. coli BW3709 (rpoS) than in the parental strain (BW2952). The rpoS mutant also released much higher concentrations of protein under pressure than the parent. We propose that RpoS-regulated functions are responsible for the increase in membrane resilience as cells enter stationary phase and that this plays a major role in the development of pressure resistance. Strains from the Keio collection with mutations in two RpoS-regulated genes, cfa (cyclopropane fatty acyl phospholipid synthase) and osmB (outer membrane lipoprotein), were significantly more pressure sensitive and took up more PI than the parent strain, with cfa having the greatest effect. Mutations in the bolA morphogene and other RpoS-regulated lipoprotein genes (osmC, osmE, osmY, and ybaY) had no effect on pressure resistance. The cytoplasmic membranes of the rpoS mutant failed to reseal after pressure treatment, and strains with mutations in osmB and nlpI (new lipoprotein) were also somewhat impaired in the ability to reseal their membranes. The cfa mutant, though pressure sensitive, was unaffected in membrane resealing, implying that the initial transient permeabilization event is critical for loss of viability rather than the failure to reseal. The enhanced pressure sensitivity of polA, recA, and xthA mutants suggested that DNA may be a target of oxidative stress in pressure-treated cells.     

Immune enhancement activities of silk lutein extract from Bombyx mori cocoons

Background

Declining immune function poses an important clinical challenge worldwide and supplementation with natural products that possessing immune enhancing properties is a promising approach for preventing or delaying immune function decline. Cocoons from yellow silkworms are a significant source of lutein, and this unexplored silk extract could be a viable alternative source for dietary lutein. This study assessed immunomodulatory activities of the silk lutein extract. Female BALB/c mice orally received lutein, either as silk or marigold extracts (10 or 20 mg/kg daily), or vehicle only (1% tween 80 in PBS pH 7.4) for 4 weeks. Natural killer (NK) cell activity, specific antibody production, lymphocyte subpopulations, mitogen-induced lymphocyte proliferation, and cytokine production were examined.

Results

Silk lutein extract increased NK cell activity, and the effect was dose-related whereas marigold lutein extract was ineffective. Silk lutein extract dose-dependently enhanced antibody production in pre-immunized mice but marigold lutein extract had no effect. Feeding with silk lutein extract increased the populations of CD3+ and CD4 + CD3 + cells. Silk lutein extract also stimulated concanavalin A- and lipopolysaccharide-induced proliferations of T and B lymphocytes, respectively. Moreover, silk lutein extract increased IL-2 and IFN-γ production while the effect of marigold lutein extract was undetectable.

Conclusions

Together, silk lutein extract enhanced both innate and adaptive immune functions. This preparation may prove to be an effective supplement for strengthened immunity.