Hybrid flavan-chalcones, aromatase and lipoxygenase inhibitors, from Desmos cochinchinensis

Hybrid flavan-chalcones, desmosflavans A (1) and B (2), together with three known compounds, cardamonin (3), pinocembrin (4) and chrysin (5), were isolated from leaves of Desmos cochinchinensis. Cardamonin (3) and chrysin (5) exhibited potent antioxidant activity with 15.0 and 12.2 ORAC units. Desmosflavans A (1) and B (2), pinocembrin (4), and chrysin (5) were found to be inhibitors of aromatase with respective IC₅₀ values of 1.8, 3.3, 0.9, and 0.8 μM. Desmosflavan A (1) inhibited lipoxygenase with the IC₅₀ value of 4.4 μM. Desmosflavan A (1) exhibited cytotoxic activity with IC₅₀ values of 0.29–3.75 μg/mL, while desmosflavan B (2) showed IC₅₀ values of 1.71–27.0 μg/mL.     

Savoryellales (Hypocreomycetidae, Sordariomycetes): a novel lineage of aquatic ascomycetes inferred from multiple-gene phylogenies of the genera Ascotaiwania, Ascothailandia, and Savoryella

The taxonomic placement of freshwater and marine Savoryella species has been widely debated, and the genus has been tentatively assigned to various orders in the Sordariomycetes. The genus is characterized as possessing paraphyses that deliquesce early, elongate, clavate to cylindrical asci with a poorly developed apical ring and versicolored, three-septate ascospores. We performed two combined phylogenetic analyses of different genes: (i) partial small subunit rRNA (SSU), large subunit rRNA (LSU), DNA-dependent RNA polymerase II largest subunit (rpb2) dataset and (ii) SSU rDNA, LSU rDNA, DNA-dependent RNA polymerase II largest subunit (rpb1 and rpb2), translation elongation factor 1-alpha (tef1), the 5.8S ribosomal DNA (5.8S rDNA) dataset. Our results indicate that Savoryella species formed a monophyletic group within the Sordariomycetes but showed no affinity to the Hypocreales, Halosphaeriales (now Microascales), Sordariales and Xylariales, despite earlier assignments to these orders. Savoryella, Ascotaiwania and Ascothailandia (and its anamorph, Canalisporium) formed a new lineage that has invaded both marine and freshwater habitats, indicating that these genera share a common ancestor and are closely related. Because they show no clear relationship with any named order we erect a new order Savoryellales in the subclass Hypocreomycetidae, Sordariomycetes. The genera Savoryella and Ascothailandia are monophyletic, while the position of Ascotaiwania is unresolved. All three genera are phylogenetically related and form a distinct clade similar to the unclassified group of marine ascomycetes comprising the genera Swampomyces, Torpedospora and Juncigera (TBM clade: Torpedospora/Bertia/Melanospora) in the Hypocreomycetidae incertae sedis.     

CometChip: A High-throughput 96-Well Platform for Measuring DNA Damage in Microarrayed Human Cells

DNA damaging agents can promote aging, disease and cancer and they are ubiquitous in the environment and produced within human cells as normal cellular metabolites. Ironically, at high doses DNA damaging agents are also used to treat cancer. The ability to quantify DNA damage responses is thus critical in the public health, pharmaceutical and clinical domains. Here, we describe a novel platform that exploits microfabrication techniques to pattern cells in a fixed microarray. The ‘CometChip’ is based upon the well-established single cell gel electrophoresis assay (a.k.a. the comet assay), which estimates the level of DNA damage by evaluating the extent of DNA migration through a matrix in an electrical field. The type of damage measured by this assay includes abasic sites, crosslinks, and strand breaks. Instead of being randomly dispersed in agarose in the traditional assay, cells are captured into an agarose microwell array by gravity. The platform also expands from the size of a standard microscope slide to a 96-well format, enabling parallel processing. Here we describe the protocols of using the chip to evaluate DNA damage caused by known genotoxic agents and the cellular repair response followed after exposure. Through the integration of biological and engineering principles, this method potentiates robust and sensitive measurements of DNA damage in human cells and provides the necessary throughput for genotoxicity testing, drug development, epidemiological studies and clinical assays.     

Incidence and Epidemiology of Hospitalized Influenza Cases in Rural Thailand during the Influenza A (H1N1)pdm09 Pandemic, 2009–2010

Background

Data on the burden of the 2009 influenza pandemic in Asia are limited. Influenza A(H1N1)pdm09 was first reported in Thailand in May 2009. We assessed incidence and epidemiology of influenza-associated hospitalizations during 2009–2010.

Methods

We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory infection (ALRI) in all 20 hospitals in two rural provinces. ALRI patients were sampled 1∶2 for participation in an etiology study in which nasopharyngeal swabs were collected for influenza virus testing by PCR.

Results

Of 7,207 patients tested, 902 (12.5%) were influenza-positive, including 190 (7.8%) of 2,436 children aged <5 years; 86% were influenza A virus (46% A(H1N1)pdm09, 30% H3N2, 6.5% H1N1, 3.5% not subtyped) and 13% were influenza B virus. Cases of influenza A(H1N1)pdm09 first peaked in August 2009 when 17% of tested patients were positive. Subsequent peaks during 2009 and 2010 represented a mix of influenza A(H1N1)pdm09, H3N2, and influenza B viruses. The estimated annual incidence of hospitalized influenza cases was 136 per 100,000, highest in ages <5 years (477 per 100,000) and >75 years (407 per 100,000). The incidence of influenza A(H1N1)pdm09 was 62 per 100,000 (214 per 100,000 in children <5 years). Eleven influenza-infected patients required mechanical ventilation, and four patients died, all adults with influenza A(H1N1)pdm09 (1) or H3N2 (3).

Conclusions

Influenza-associated hospitalization rates in Thailand during 2009–10 were substantial and exceeded rates described in western countries. Influenza A(H1N1)pdm09 predominated, but H3N2 also caused notable morbidity. Expanded influenza vaccination coverage could have considerable public health impact, especially in young children.     

Source of high pathogenicity of an avian influenza virus H5N1: why H5 is better cleaved by furin

The origin of the high pathogenicity of an emerging avian influenza H5N1 due to the -RRRKK- insertion at the cleavage loop of the hemagglutinin H5, was studied using the molecular dynamics technique, in comparison with those of the noninserted H5 and H3 bound to the furin (FR) active site. The cleavage loop of the highly pathogenic H5 was found to bind strongly to the FR cavity, serving as a conformation suitable for the proteolytic reaction. With this configuration, the appropriate interatomic distances were found for all three reaction centers of the enzyme-substrate complex: the arrangement of the catalytic triad, attachment of the catalytic Ser³⁶⁸ to the reactive S1-Arg, and formation of the oxyanion hole. Experimentally, the -RRRKK- insertion was also found to increase in cleavage of hemagglutinin by FR. The simulated data provide a clear answer to the question of why inserted H5 is better cleaved by FR than the other subtypes, explaining the high pathogenicity of avian influenza H5N1.     

Decolorization of synthetic melanoidins-containing wastewater by a bacterial consortium

The presence of melanoidins in molasses wastewater leads to water pollution both due to its dark brown color and its COD contents. In this study, a bacterial consortium isolated from waterfall sediment was tested for its decolorization. The identification of culturable bacteria by 16S rDNA based approach showed that the consortium composed of Klebsiella oxytoca, Serratia mercescens, Citrobacter sp. and unknown bacterium. In the context of academic study, prevention on the difficulties of providing effluent as well as its variations in compositions, several synthetic media prepared with respect to color and COD contents based on analysis of molasses wastewater, i.e., Viandox sauce (13.5% v/v), caramel (30% w/v), beet molasses wastewater (41.5% v/v) and sugarcane molasses wastewater (20% v/v) were used for decolorization using consortium with color removal 9.5, 1.13, 8.02 and 17.5%, respectively, within 2 days. However, Viandox sauce was retained for further study. The effect of initial pH and Viandox concentration on decolorization and growth of bacterial consortium were further determined. The highest decolorization of 18.3% was achieved at pH 4 after 2 day of incubation. Experiments on fresh or used medium and used or fresh bacterial cells, led to conclusion that the limitation of decolorization was due to nutritional deficiency. The effect of aeration on decolorization was also carried out in 2 L laboratory-scale suspended cell bioreactor. The maximum decolorization was 19.3% with aeration at KLa = 2.5836 h⁻¹ (0.1 vvm).     

Influence of stereoisomer of dispiro-1,2,4,5-tetraoxanes on their binding mode with heme and on antimalarial activity: molecular docking studies

Based on the fact that different isomers may exhibit substantial distinct activities, quantum chemical calculations and automated molecular docking simulations were carried out for 13 dispiro-1,2,4,5-tetraoxane compounds, which experimentally exist as a mixture of several isomers, to elucidate the most probable isomer(s) responsible for their antimalarial activity. The results indicate significant effects of stereoisomer on the binding mode and the activity. Moreover, the antimalarial potency of each compound can be described by the docking results. Compounds 1, 2, 4, 5, 7, and 9 have the most probable isomers coordinate suitably with heme iron and hence they have high activities while the most probable isomer in compounds 3 and 8 could not bind appropriately to heme yielding only moderate activities. On the other hand, the steric hindrance in compounds 11-13 prevents an approach of heme iron to peroxide bonds resulting in a devoid of antimalarial activity. However, compounds 6 and 10 with isopropyl substituents exhibit a different docking character, which is possibly caused by a limitation in molecular flexibility of the available docking technique. Our results can be used as a guideline for stereochemical control in synthesis process to improve drug's potency.     

Human immunodeficiency virus type 1 primary isolate neutralization resistance is associated with the syncytium-inducing phenotype and lower CD4 cell counts in subtype CRF01_AE-infected patients

A number of human immunodeficiency virus type 1 (HIV-1) non-B-subtype products have been developed for present or future vaccine trials; in Thailand, several studies using subtype B and/or CRF01_AE vaccines have been conducted. To better characterize the biologic properties of these subtypes, 70 HIV-1 subtype B and E isolates were phenotyped as syncytium-inducing (SI) or non-syncytium-inducing (NSI) isolates and assessed for sensitivity to neutralizing antibody (NAb). A significantly higher number of NSI subtype E viruses were neutralization sensitive than SI subtype E viruses (P = 0.009), while no association between viral phenotype and sensitivity to NAb was observed for subtype B (P = 0.856), suggesting a difference in the neutralization patterns of subtypes B and E. Strikingly, concurrent CD4 T-cell numbers were significantly lower for subtype E-infected patients whose isolates were more resistant to NAb, both for the overall study group (P < 0.001) as well as for the 22 patients with NSI isolates (P = 0.013). Characterization of the evolution of biologic properties of both B and non-B HIV-1 subtypes will provide a clearer understanding of the repertoire of antibodies that must be elicited for a vaccine to be effective against all phenotypes and subtypes.