Molecular evidence of Wolbachia infection in natural populations of tropical odonates

Wolbachia are endosymbiotic bacteria that cause reproductive alterations in numerous arthropod species. Using a PCR-based method, we found that, out of 33 odonate species, four species were infected with Wolbachia. This finding represents the first record of Wolbachia infection in tropical odonates. Identical wsp gene sequences were found in the Wolbachia-infected common odonate species, Agriocnemis f. femina, collected from different locations in Thailand. The infection frequencies in several natural populations suggest that replacement of uninfected populations by Wolbachia-infected ones has recently occurred in this damselfly species.     

The 1.1 A crystal structure of human TGF-beta type II receptor ligand binding domain

Transforming growth factor beta (TGF-beta) is involved in a wide range of biological functions including development, carcinogenesis, and immune regulation. Here we report the 1.1 A resolution crystal structure of human TGF-beta type II receptor ectodomain (TBRII). The overall structure of TBRII is similar to that of activin type II receptor ectodomain (ActRII) and bone morphogenic protein receptor type IA (BRIA). It displays a three-finger toxin fold with fingers formed by the beta strand pairs beta1-beta2, beta3-beta4, and beta5-beta6. The first finger in the TBRII is significantly longer than in ActRII and BRIA and folds tightly between the second finger and the C terminus. Surface charge distributions and hydrophobic patches predict potential TBRII binding sites.     

Optimization of simultaneously enzymatic fructo- and inulo-oligosaccharide production using co-substrates of sucrose and inulin from Jerusalem artichoke

Prebiotic substances are extracted from various plant materials or enzymatic hydrolysis of different substrates. The production of fructo-oligosaccharide (FOS) and inulo-oligosaccharide (IOS) was performed by applying two substrates, sucrose and inulin; oligosaccharide yields were maximized using central composite design to evaluate the parameters influencing oligosaccharide production. Inulin from Jerusalem artichoke (5–15% w/v), sucrose (50–70% w/v), and inulinase from Aspergillus niger (2–7 U/g) were used as variable parameters for optimization. Based on our results, the application of sucrose and inulin as co-substrates for oligosaccharide production through inulinase hydrolysis and synthesis is viable in comparative to a method using a single substrate. Maximum yields (674.82?mg/g substrate) were obtained with 5.95% of inulin, 59.87% of sucrose, and 5.68 U/g of inulinase, with an incubation period of 9?hr. The use of sucrose and inulin as co-substrates in the reaction simultaneously produced FOS and IOS from sucrose and inulin. Total conversion yield was approximately 67%. Our results support the high value-added production of oligosaccharides using Jerusalem artichoke, which is generally used as a substrate in prebiotics and/or bioethanol production.     

Distribution and Abundance of Opisthorchis viverrini Metacercariae in Cyprinid Fish in Northeastern Thailand

To increase public health awareness for prevention of opisthorchiasis caused by eating raw freshwater fish, the distribution and abundance of Opisthorchis viverrini metacercariae (OV MC) was investigated in freshwater fish obtained from 20 provinces in northeastern Thailand between April 2011 and February 2012. A cross-sectional survey was conducted on 12,890 fish consisting of 13 species randomly caught from 26 rivers, 10 dams, and 38 ponds/lakes. Fish, were collected in each of the rainy and winter seasons from each province. Fish were identified, counted, weighed, and digested using pepsin-HCl. Samples were examined for OV MC by a sedimentation method, and metacercariae were identified under a stereomicroscope. OV MC were found in 6 species of fish; i.e., Cyclocheilichthys armatus, Puntius orphoides, Hampala dispar, Henicorhynchus siamensis, Osteochilus hasselti, and Puntioplites proctozysron from localities in 13 provinces. Among the sites where OV MC-infected fish were found, 70.0% were dams, 23.7% were ponds/lakes, and 7.7% were rivers. The mean intensity of OV MC ranged from 0.01 to 6.5 cysts per fish (or 1.3-287.5 cysts per kg of fish). A high mean intensity of OV MC per fish (>3 cysts) was found in 5 provinces: Amnat Charoen (6.5 cysts), Nakhon Phanom (4.3), Mukdahan (4.1), Khon Kaen, (3.5) and Si Sa Ket (3.4). In conclusion, OV MC are prevalent in natural cyprinid fish, with the infection rate varying according to fish species and habitats.     

Prolonged inhibitory effects against planktonic growth,adherence, and biofilm formation of pathogens causing ventilator-associated pneumonia using a novel polyamide/silver nanoparticle composite-coated endotracheal tube

Abstract

Microbial cells can rapidly form biofilm on endotracheal tubes (ETT) causing ventilator-associated pneumonia, a serious complication in patients receiving mechanical ventilation. A novel polyamide with a good balance of hydrophilic/hydrophobic moieties was used for the embedment of green-reduction silver nanoparticles (AgNPs) for the composite-coated ETT. The films were conformal with a thickness of ～ 17?±?3?µm accommodating high loading of 60?±?35?nm spherical-shaped AgNPs. The coated ETT resulted in a significant difference in reducing both planktonic growth and microbial adhesion of single and mixed-species cultures, compared with uncoated ETT (p?<?0.05). A time-kill assay demonstrated rapid bactericidal effects of the coating on bacterial growth and cell adhesion to ETT surface. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus, commonly encountered pathogens, was inhibited by > 96% after incubation for 72?h. Polyamide/AgNP composite-coated ETT provided a broad-spectrum activity against both Gram-positive and Gram-negative bacteria as well as Candida albicans and prolonged antimicrobial activity.     

Mapping airborne pollen of papaya (Carica papaya L.) and its distribution related to land use using GIS and remote sensing

Papaya is an economically important plant in Thailand for domestic consumption and export. However, papaya is extremely susceptible to disease caused by the papaya ring spot virus. Although transgenic papaya has been developed, commercial cultivation of transgenic plants in Thailand is still illegal. One concern is cross-pollination to conventional varieties. In this study, windborne-pollen dispersion of papaya (Carica papaya L.) was investigated using geographic information systems (GIS) and remotely sensed data. Pollen traps were placed around a papaya plot in eight geographic directions, with radiuses varying from 5 to 900 m from the plot. Pollen counts were made for 12 different dates, and data were input into a GIS database. The distribution of pollen and its relation to land use were analyzed using land use data obtained from Quickbird imagery acquired during 2007. Comparative analyses of pollen dispersal, wind direction, and speed were made using data collected from a micro-climatic station set up at a papaya plot. The furthest distance from the plot that pollen was found was at 0.9 km, a distance at which only 1 pollen grain was found. The number of pollen grains carried by wind decreased as distance increased. The direction of dispersal was not in accordance with wind direction data. Most pollen grains were found in agricultural areas and bare land. The total number of pollen grains found in exposed areas was considerably higher than the total found in areas sheltered by dense tree lines.     

Molecular Evidence of <Emphasis Type="Italic">Wolbachia</Emphasis> Infection in Natural Populations of Tropical Odonates

Wolbachia are endosymbiotic bacteria that cause reproductive alterations in numerous arthropod species. Using a PCR-based method, we found that, out of 33 odonate species, four species were infected with Wolbachia. This finding represents the first record of Wolbachia infection in tropical odonates. Identical wsp gene sequences were found in the Wolbachia-infected common odonate species, Agriocnemis f. femina, collected from different locations in Thailand. The infection frequencies in several natural populations suggest that replacement of uninfected populations by Wolbachia-infected ones has recently occurred in this damselfly species.Received: 12 November 2002 / Accepted: 13 December 2002