Experimental infections of a ciliate Tetrahymena pyriformis on ornamental fishes

SUMMARY: Experimental infection of Tetrahymena pyriformis was conducted on ornamental fishes with skin wounded by acetic acid treatment. Among fishes used in this experimental infection, guppy Poecilia reticulata , pristella Pristella maxillaris , neontetra Paracheirodon innesi and cherry barbs Puntius titteya proved to be sensitive to challenge, while medaka Oryzias latipes , dwarf gourami Colisa lalia , goldfish Carassius auratus , platy Xiphophorus maculatus and angelfish Pterophyllum scalare were resistant. In catfish Corydoras aeneus infection was unsuccessful. Exposure to Tetrahymena at ≥100 cells/mL at 25 to 30°C and at pH of 6.0 to 8.0 resulted in the successful infection of some sensitive fish species. Histological and bacteriological observations suggest that deeply destroyed skin tissues from the acid-treated method are the primary factors in successful infection.     

Genetic characterization of a betanodavirus isolated from a clinical disease outbreak in farm‐raised tilapia Oreochromis niloticus (L.) in Thailand

Betanodavirus infection was diagnosed in larvae of farm‐raised tilapia Oreochromis niloticus (L.), in central Thailand. Extensive vacuolar degeneration and neuronal necrosis were observed in histological sections with positive immunohistochemical staining for betanodavirus. Molecular phylogenetic analysis was performed based on the nucleotide sequences (1333 bases) of the capsid protein gene. The virus strain was highly homologous (93.07–93.88%) and closely related to red‐spotted grouper nervous necrosis virus (RGNNV).     

Effects of Pouteria cambodiana extracts on in vitro immunomodulatory activity of mouse immune system

Immunomodulatory activity of water and acetone extracts of stem bark of Pouteria cambodiana was examined on murine macrophage phagocytosis [nitroblue tetrazolium (NBT) dye reduction and lysosomal enzyme activity] and proliferation of splenocytes and bone marrow cells by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with and without lipopolysaccharide (LPS) or pokeweed mitogen (PWM). Both aqueous and acetone extracts presented immunomodulatory activity without clear dose response relationship.     

Photosynthetic activity of MSMA-resistant and -susceptible common cocklebur

MSMA-resistant (R) and -susceptible (S) biotypes of common cocklebur (Xanthium strumarium L.) were used to study PSI and PSII activities, and chlorophyll and carotenoid content of MSMA-treated and -untreated R and S biotypes. MSMA at 1, 10, and 100 mg/L did not inhibit either PSI or PSII activities. The R biotype had higher PSI and PSII activity than the S biotype with and without MSMA treatments. R biotype leaf discs had higher chlorophyll and carotenoid content than the S biotype after treatment with MSMA; the S biotype cotyldeons had higher levels of both pigments as compared to the R biotype cotyledons. MSMA induced a reduction in both pigments in S biotype cotyledons, and in young and mature leaf discs. Results indicate that photosynthetic capability might indirectly be involved in the resistance mechanism and carotenoids may protect against MSMA toxicity, possibly caused by an induced free radical mechanism.     

Improving the impact resistance of p-aramid fabrics by sequential impregnation with shear thickening fluid

A simple and effective method for impregnation of p-aramid (Kevlar^®) fabric with shear thickening fluid (STF) has been developed in this research. Kevlar fabric was impregnated with STF in two stages in a sequential manner. Three levels of pressure (0.5, 1 and 2 bar) were used in each stage of impregnation. It was observed that impact energy absorption by Kevlar fabrics, impregnated with STF in this newly developed method, increased significantly as compared to untreated Kevlar fabrics and Kevlar fabrics treated with STF in conventional way (single step impregnation). Better results were obtained when the first impregnation pressure was higher than that of the second, even with same combination of pressures. Such fabrics also showed a much higher STF add-on (~18 %) as compared to that of fabrics impregnated in single step (3-5 %). Low velocity ballistic tests also confirmed the advantages of the new method as sequentially impregnated fabric showed 124.8 % and 24.4 % increase in impact energy absorption compared to untreated and STF impregnated Kevlar fabrics in single step, respectively.     

Modulation of intestinal morphology and immunity in nile tilapia (Oreochromis niloticus) by Lactobacillus rhamnosus GG

The use of lactic acid bacteria from human origins as a potential probiotic supplementation in aquaculture feed is now widely accepted. Here, we examined some of the properties and mechanisms of the action of Lactobacillus rhamnosus GG, originating from humans, on growth performance, gut mucosal immunity and humoral and cellular immune response in tilapia (Oreochromis niloticus). The results suggested that supplementation of L. rhamnosus gave an advantage in promoting the intestinal structure and the mucosal immunity of tilapia. Probiotic fish had a greater villous height in all parts of the intestines and, significantly, in the proximal and middle part. The population of intraepithelial lymphocytes was significantly higher in the probiotic group than in the control group in all parts of the intestines. The population of acidophilic granulocyte in the probiotic group was significantly higher at the proximal and distal parts when compared with the control group. The higher serum complement activity as well as the enhanced phagocytosis and killing ability of the head kidney leukocytes in the probiotic supplemented fish corresponded with the higher level of TNF alpha and IL-1 gene expression, suggesting that the induction of IL-1 and TNF alpha cytokines by L. rhamnosus served as an important regulator of gut associated immune systems.     

Effects of Butea superba on reproductive systems of rats

The effects of Butea superba on the reproductive system in male Wistar rats were investigated. The animals were fed daily with the powdered crude drug suspended in distilled water by a gastric tube at the dose of 2, 25, 250 and 1250 mg/kg body weight for 8 weeks. Rats fed with 1 ml of distilled water were used as a negative control. The weights of all vital organs in all treated groups were not different from the control. The percentage weight ratios of body weights of seminal vesicles and prostate glands were not different from the control, except that the testis of the group fed with 1250 mg/kg was significantly different from the control and the other treated groups. In addition, the sperm counts in this group showed about 16% more than the control group. Hematology as well as the liver and kidney function of all treated groups showed no difference from the control. B. superba, drug at 250 mg/kg which was 100 times more than the Thai FDA recommended dose for humans appeared to be safe in rats. The crude drug has demonstrated an increase tendency on testis weight and sperm counts in rat. The information from the present study can be used to explain the Thai folklore application of this plant in Thailand.     

Nodavirus associated with pathological changes in adult spotted coralgroupers (Plectropomus maculatus) in Thailand with viral nervous necrosis

The present study characterized viral nervous necrosis in sea cage-reared adult spotted coralgroupers (Plectropomus maculatus). Histopathological study showed extensive vacuolation and neuronal necrosis of the olfactory bulb and the optic lobe of the forebrain and the inner and outer nuclear layer of retina. Mild necrosis was observed in the spinal cord. Homogeneous intranuclear inclusion bodies were noted in the hyperplastic and hypertrophic glandular epithelial cells of the swim bladder suggesting viral etiology. Etiological diagnosis of VNN was confirmed by RT-PCR, immunohistochemistry and in situ hybridization. The immunohistochemistry and in situ hybridization gave strongly positive staining in the same area of the infected cells of the brain, spinal cord and retina correlating with histopathological changes. No positive reaction was detectable in the affected gas glandular epithelium and other organs, confirming the consistent neurotropism of this nodavirus. Nodavirus was mainly detected in the olfactory bulb of the brain. The result suggests nasal transmission was the major route of infection.