Experimental studies on Marek's disease in Japanese quail (Coturnix coturnix japonica)

Day-old quails experimentally infected with Marek's disease (MD) virus of quail origin developed lymphoid tumors. The severity of the disease increased considerably with serial passage. Tumor transplants could be made with cells derived from gross tumors in skeletal muscles, spleen cells, and blood from MD-affected quails. After five to six serial transplants, the tumor could not be transplanted further. Marek's disease tumor-associated surface antigen (MATSA) was demonstrated in lymphoid cells of spleen and peripheral blood lymphocytes of MD-affected quails. The MATSA of quail differed from the MATSA of chicken. Chickens were susceptible to MD virus isolated and propagated in quails.     

Immunopathology of Marek's disease in quails: presence of antinuclear antibody and immune complex.

Antinuclear antibody (ANA), a marker for autoimmune reactions, was detected in the sera of quails with Marek's disease (MD). The autoantibody was detected 3 weeks after infection in quails infected with chicken Marek's disease virus and 4 weeks after infection in quails infected with quail Marek's disease virus. The ANA titers were low and ranged from 10 to 40. A speckled type of nuclear fluorescence was the characteristic staining feature. In addition to the presence of ANA, immune complexes (IC) were also detected in the kidney glomeruli of quail infected with Marek's disease virus. Initially about 25-30% of the glomeruli in the kidneys of infected quails had IC deposits. In subsequent periods, the amount of IC deposit and the number of glomeruli showing IC also increased considerably. The findings of the present study suggested autoimmunity may play a pathogenic role in MD.     

Hydraulic conductivity as an index of soil structure

Good soil structure is well recognised as a must for intensive cultivation. Various indices of soil structure suggested by earlier investigators had their own limited use in their application to the practical problems on the field. RICHARDS et al (1960) suggested compacted bulk density and hydraulic conductivity on the compacted samples as means of evaluating the structural status of soils. Problems of compaction, inadequate aeration and undesirable soil moisture relationships for growth of plants that are associated with soil structure depend on effective porosity (DAKSHINAMURTI, 1959) and porespace distribution in the soil for their solution. Hydraulic conductivity being related to the effective porosity should work out as a comparatively better index of soil structure. In the present investigation hydraulic conductivity and bulk density under varying conditions of compaction were studied and their significance and sensitivity as indices in comparison to other indices of soil structure were discussed.     

Microcystis aeruginosa (Kütz) incorporated diets increase immunity and survival of Indian major carp Labeo rohita (Ham.) against Aeromonas hydrophila infection

The aim of this study was to evaluate dietary dosages of Microcystis on the immune response and disease resistance against infections due to the opportunistic pathogen Aeromonas hydrophila in Labeo rohita fingerlings. Labeo rohita fingerlings were fed diet containing 0 (Control), 0.5, 1.0 and 5 g Microcystis powder kg^?1 dry diet for 90 days. Three replicate groups of fish averaging 20 ± 2 g were fed for 3 months daily. At 30 days interval, samples were assayed for different biochemical [serum total protein, albumin, globulin, albumin:globulin (A:G) ratio] and immunological (superoxide anion production, lysozyme and serum bactericidal activity) parameters. The results demonstrate that fish fed Microcystis showed increased levels of lysozyme, serum bactericidal activity, serum protein and albumin (P ≤ 0.05) as compared with the control group. After 90 days, fish were challenged with A. hydrophila and mortality (%) was recorded up to day 10 postchallenge. The group fed 1.0 g Microcystis kg^?1 dry diet showed the highest percentage survival (72%). These results indicate that Microcystis aeruginosa stimulates the immunity and makes L. rohita more resistant to infection by A. hydrophila when fed in dried form in feed.     

Traits-related QTLs and genes and their potential applications in rice improvement under low phosphorus condition

The genetic improvement of rice over past decades has led to the loss of several genes which are responsible for nutrient acquisition and soil-related stresses. Phosphorus (P) is a non-renewable resource and inevitable element of metabolic functions in plants. By pedogenesis process, organic matter contributes to renewing soil P in lesser extent. Therefore, improvement of the P use efficiency is one of the most imperative traits in rice breeding program, which is governed by quantitative trait loci (QTLs). QTLs controlling low P associated morphological and physiological traits in rice were investigated mostly during last one and half decade by using diverse mapping populations. Comprehensive and meticulous survey from literature, we found that to date 133 P associated QTLs of morpho-physiological traits were reported to be distributed on twelve chromosomes and majority of these QTLs localized on chromosome 1, 2 and 12. For the first time, a complete figure is presented in this review on chromosome wise with respective QTLs associated with low P for easy understanding and selecting markers for future prospect. Further, it is necessary to understand the molecular mechanisms and regulation of genes and traits associated with low P to develop tolerant rice cultivars using functional marker-assisted selection.     

Improved assessment of mycelial growth stimulation by low doses of mefenoxam in plant pathogenic <Emphasis Type="Italic">Globisporangium</Emphasis> species

Globisporangium Uzuhashi, Tojo & Kakish. (syn. Pythium Pringsheim) species cause many plant diseases, including Pythium damping-off, leaf and fruit blights, and root rots. Fungicide resistant isolates are selected by repeated use of a single active ingredient on infected crops without rotation. Previous studies demonstrated increased pathogenicity and radial growth in a mefenoxam resistant isolate of Pythium aphanidermatum when exposed to sub-lethal doses of fungicides and ethanol. In those studies, reproducibility of in vitro assays was difficult to achieve due to large variations among trials. This study aimed to examine two protocols for improved reproducibility during the assessment of biphasic dose-responses in mefenoxam-resistant isolates of Globisporangium ultimum and G. irregulare. Two different growth related endpoints, total growth area and total dry mass weight, were assessed. Assays were conducted using ten concentrations of mefenoxam ranging from 0.01 to 1,000 μg/ml. Statistically-significant stimulatory effects were observed in the two Globisporangium species using the two growth related endpoints. Because of its better reproducibility, mycelial growth area is recommended as an endpoint for future studies of chemical hormesis on growth of Globisporangium spp.     

An improvised in vitro vegetative propagation technique for <Emphasis Type="Italic">Bambusa tulda</Emphasis>: influence of season,sterilization and hormones

Season and concentration of sterilizing agents play a significant role for establishment of aseptic in vitro shoot cultures and sprouting of nodal explants from field growing culms of bamboo species. In the present investigation the nodal segment explants of Bambusa tulda Roxb collected in different seasons and treated with various concentrations of HgCl₂ showed significant variation in aseptic culture establishment and bud break. The rainy season (July–August) recorded with highest of 78% aseptic culture establishment whereas autumn recorded with lowest 46%. Summer and winter seasons emerged to be the best period, registering > 60% in vitro bud break. On the other hand, the autumn season had the lowest value for bud break, i.e. 42%. Among different doses of sterilizing agent tried, HgCl₂ 0.1% found to be suitable for maximum aseptic culture establishment (66%) as well as bud break (59%). However, among the interactions, summer season and the dose of 0.1% HgCl₂ exhibited maximum of 73% response for both aseptic culture establishment and bud break. MS medium (liquid) enriched with 5.0 µM BA + 5.0 µM Kn [Kinetin (N6-Furfuryladenine)] with additional supplementation of 100 µM glutamine + 0.1 µM IAA supported a maximum in vitro shoot multiplication of 4.75 fold. The proliferated shoots were successfully rooted on MS medium (liquid) supplemented 40 µM coumarin. The plantlets transferred to the polythene bags showed 98% survival.     

Physical properties of tung seed: An industrial oil yielding crop

Data on physical properties of seeds have significant importance for machinery and process equipments design. This study was conducted to investigate some physical properties of tung seed (Aleutites Fordii) namely, dimensions, 100 unit mass, arithmetic mean diameter, geometric mean diameter, sphericity, aspect ratio, surface area, bulk density, true density, porosity, terminal velocity and coefficient of friction. The applications of these properties are also discussed. The tung seed has an average of 13.24% (d.b.) moisture and 40.37% oil content. The average seed length, width, thickness were 22.61 mm, 20.35 mm, 13.95 mm, respectively. The average surface area of tung seed is 1084.20 mm² while the sphericity and aspect ratio were 0.82 and 90.07%, respectively. The average bulk density of seed was 0.502 g/cm³ while the true density was 0.995 g/cm³, and the corresponding porosity was 49.88%. The terminal velocity was 8.3 m/s. The static coefficient of friction on three different contacting materials has been found out and the results showed that the mean value of static coefficient friction was least in case of aluminum sheet while it is highest for plywood.     

Ontogeny of the digestive tract in butter catfish Ompok bimaculatus (Bloch) larvae

The ontogeny of the digestive tract was studied histologically in butter catfish Ompok bimaculatus from hatching to 30?days post-hatching (dph). At hatching, the digestive tract of butter catfish consisted of a straight tube with a smooth lumen dorsally attached to the yolk sac. Between 1 and 2 dph, the mouth opened, oral valves were visible and canine-like teeth and taste buds were detected. During this period, intestine was differentiated into the anterior and posterior intestine, and the digestive accessory glands were also developed. Exogenous feeding started at 2?dph, and there was a 2-day mixed endogenous–exogenous feeding period. Most of the yolk sac reserves were consumed between 2 and 3 dph, and by 5?dph, the yolk sac was completely depleted and no longer visible in histological sections. Between 3 and 4 dph, several vacuoles (neutral lipids) were observed in the intestine and also in hepatocytes, indicating a functional absorption of nutrients from food. At 8 dph, differentiation of gastric glands was noticed, and by 9–11?dph, there were abundant gastric tubular glands arranged along numerous longitudinal folds. During the same period, pyloric sphincter appeared as an epithelial fold that separated the stomach from the anterior intestine. From 12 dph to the end of the study at 30?dph, no noticeable histological modifications were observed. The development of gastric glands is considered as the last major events in digestive tract development and their presence designates the end of larval period and the onset of the juvenile period. Hence, it is suggested that, butter catfish larvae have a morphologically complete digestive tract by 12?dph. These findings on the development of the digestive system in butter catfish may lead to a better understanding of the ontogeny and would be useful to improve the larval rearing techniques of this promising catfish species for freshwater aquaculture diversification.