Dietary levamisole modulates the immune response and disease resistance of Asian catfish Clarias batrachus (Linnaeus)

In order to determine the immunomodulatory effect of dietary levamisole in Asian catfish (Clarias batrachus), fish were fed four different diets for 10 days: a formulated diet as control and the same diet supplemented with 50, 150 or 450 mg levamisole kg^?1 feed. The serum bacterial agglutination titre against Aeromonas hydrophila as a measure of specific immunity, serum haemagglutination titre, natural haemolytic complement activity (ACH₅₀), myeloperoxidase and lysozyme activities, total protein level and oxidative radical production by neutrophils as a measure of non‐specific immunity as well as disease resistance against A. hydrophila challenge to separate vaccinated and non‐vaccinated groups were evaluated at 0, 1, 2 and 3 weeks after last administration of levamisole. Levamisole supplement at the lowest level (50 mg kg^?1) significantly enhanced oxidative radical production and serum myeloperoxidase (MPO) content immediately after 10 days of feeding, which reached peak values after 3 and 2 weeks of feeding respectively. Haemolytic complement and haemagglutination titre were significantly enhanced after 3 and 1 weeks respectively. Haemolytic complement activity and MPO activities were significantly raised to 150 mg kg^?1 after 3 and 2 weeks, respectively. At the highest level of levamisole feeding (450 mg kg^?1) significant decreases in superoxide production and complement activity were measured immediately after levamisole feeding, which returned to the normal level after 1 week post‐ feeding. Fish were challenged with a virulent strain of A. hydrophila at 0, 1, 2 and 3 weeks after levamisole feeding, and the cumulative per cent survival was recorded over 10 days. Feeding levamisole at 50, 150 or 450 mg kg^?1 increased per cent survival in vaccinated fish immediately after levamisole feeding, and survival was significantly higher at 450 mg kg^?1. There was no difference in mortality patterns in non‐vaccinated fish. The results support the use of levamisole at 50 mg kg^?1 feed for 10 days as an immunostimulant in Asian catfish farming.     

Modeling the water and nitrogen transports in a soil–paddy–atmosphere system using HYDRUS-1D and lysimeter experiment

Efficient water and fertilizer use is of paramount importance both in rain-fed and irrigated rice cultivation systems to tread off between the crop water demand during the dry spell and the fertilizer leaching. This lysimeter study on paddy in a lateritic sandy loam soil of the eastern India, to simulate the water and solute transports using the HYDRUS-1D model, reveals that this model could very well simulate the soil depth-specific variations of water pressure heads and nitrogen (N) concentrations with the efficiency of >86 and 89%, respectively. The change in the level of water ponding depth did not have a significant effect on the time to peak and the temporal variability of N concentration in the bottom soil layer. The lysimeter-scale water balance analysis indicated that the average deep percolation loss and crop water use were 35.01 ± 2.03 and 39.74 ± 1.49% of the total water applied during the crop growth period, respectively. Similarly, the amount of N stored in the plant and lost through soil storage, deep percolation, and other losses (mineralization, denitrification, and gaseous N loss to the atmosphere through plant leaves) were 1.60 ± 0.16, 0.17 ± 0.04, 12.00 ± 0.48, and 86.23 ± 0.41% of the total applied nitrogen, respectively. The simulation results reveal that a constant ponding depth of 3 cm could be maintained in paddy fields to reduce the N leaching loss to 7.5 kgN/ha.     

A comparative study on certain enzymes of the granulocyte from different ruminant species

In the present study the level of enzyme hydrolases (alkaline phosphatase, myeloperoxidase, elastase, arginase, lysozyme and β-galactosidase) of polymorphonuclear cell (PMN) granules in different ruminant species and their release in response to activation was studied. Buffalo PMN alkaline phosphatase activity was higher (P < 0.01) than in PMNs of cattle and goats. Interestingly, myeloperoxidase was higher in cattle PMNs and least in goat PMNs (P < 0.01), a similar pattern was observed in the distribution of enzyme arginase. As far as lysozyme is concerned, its activity was significantly higher (P < 0.01) in PMNs of buffaloes than in the case of cattle and goat PMNs. On activation, these cells released MPO and elastase, in all the species studied, while lysozyme was secreted only in buffalo PMN cells. Activity of certain enzymes related to oxidant defence systems such as glutathione peroxidase and glutathione reductase were higher in cattle and goats compared to that in buffaloes. These observations are likely to have bearing on immunodefense roles played by PMNs and reflected differences among the ruminant species studied.     

Immunosuppressive effects of aflatoxin B1 in Indian major carp (Labeo rohita).

Aflatoxin B1 (AFB1) is a potent immunomodulator in endotherms. The experiment was carried out to study the immunosuppressive nature of AFB1 in one ectothermic species of Indian major carp. Graded levels (0, 1.25, 5.00 mg/kg of body weight) of purified AFB1 were intraperitoneally (i.p.) injected into rohu (Labeo rohita) fingerlings weighing 30-50 g, and the fish were observed for a period of 90 days. At the end of the trial, blood samples were collected from the control group as well as the AFB1 injected fish and were screened for nitroblue tetrazolium (NBT) assay, serum total protein, albumin, globulin, albumin-globulin ratio (A:G), serum bactericidal activity and bacterial agglutination titre against Edwardsiella tarda. The aflatoxin-treated fish revealed a reduction of total protein, globulin levels, bacterial agglutination titre, NBT and serum bactericidal activities, as well as an enhanced A:G ratio without change in albumin concentration, irrespective of dose levels of toxin treatment, when compared to the control group. Thus, AFB1 proved to be immunosuppressive in rohu even at the lowest dose (1.25 mg/kg body weight) of toxin treatment. This could be of economic significance in intensive culture systems of rohu.     

Algal Phlorotannins as Novel Antibacterial Agents with Reference to the Antioxidant Modulation: Current Advances and Future Directions

The increasing drug resistance of infectious microorganisms is considered a primary concern of global health care. The screening and identification of natural compounds with antibacterial properties have gained immense popularity in recent times. It has previously been shown that several bioactive compounds derived from marine algae exhibit antibacterial activity. Similarly, polyphenolic compounds are generally known to possess promising antibacterial capacity, among other capacities. Phlorotannins (PTs), an important group of algae-derived polyphenolic compounds, have been considered potent antibacterial agents both as single drug entities and in combination with commercially available antibacterial drugs. In this context, this article reviews the antibacterial properties of polyphenols in brown algae, with particular reference to PTs. Cell death through various molecular modes of action and the specific inhibition of biofilm formation by PTs were the key discussion of this review. The synergy between drugs was also discussed in light of the potential use of PTs as adjuvants in the pharmacological antibacterial treatment.     

OsSUV3 transgenic rice maintains higher endogenous levels of plant hormones that mitigates adverse effects of salinity and sustains crop productivity

Background

The SUV3 (suppressor of Var 3) gene encodes a DNA and RNA helicase, which is localized in the mitochondria. Plant SUV3 has not yet been characterized in detail. However, the Arabidopsis ortholog of SUV3 (AT4G14790) has been shown to be involved in embryo sac development. Previously, we have reported that rice SUV3 functions as DNA and RNA helicase and provides salinity stress tolerance by maintaining photosynthesis and antioxidant machinery. Here, we report further analysis of the transgenic OsSUV3 rice plants under salt stress.

Findings

The transgenic OsSUV3 overexpressing rice T₁ lines showed significantly higher endogenous content of plant hormones viz., gibberellic acid (GA₃), zeatin (Z) and indole-3-acetic acid (IAA) in leaf, stem and root as compared to wild-type (WT), vector control (VC) and antisense (AS) plants under salt (200 mM NaCl) stress condition. A similar trend of endogenous plant hormones profile was also reflected in the T₂ generation of OsSUV3 transgenic rice under defined parameters and stress condition.

Conclusions

In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.     

Genetic Relationship and Structure Analysis of Root Growth Angle for Improvement of Drought Avoidance in Early and Mid-Early Maturing Rice Genotypes

Deeper rooting 1(Dro1) and Deeper rooting 2(Dro2) are the QTLs that contribute considerably to root growth angle assisting in deeper rooting of rice plant. In the present study, a set of 348 genotypes were shortlisted from rice germplasm based on root angle study. Screening results of the germplasm lines under drought stress identified 25 drought tolerant donor lines based on leaf rolling, leaf drying, spikelet fertility and single plant yield. A panel containing 101 genotypes was constituted based on screening results and genotyped using Dro1 and Dro2 markers. Structure software categorized the genotypes into four sub-populations with different fixation index values for root growth angle. The clustering analysis and principal coordinate analysis could differentiate the genotypes with or without deeper rooting trait. The dendrogram constructed based on the molecular screening for deep rooting QTLs showed clear distinction between the rainfed upland cultivars and irrigated genotypes. Eleven genotypes, namely Dular, Tepiboro, Surjamukhi, Bamawpyan, N22, Dinorado, Karni, Kusuma, Bowdel, Lalsankari and Laxmikajal, possessed both the QTLs, whereas 67 genotypes possessed only Dro1. The average angle of Dro positive genotypes ranged from 82.7° to 89.7°. These genotypes possessing the deeper rooting QTLs can be taken as donor lines to be used in marker-assisted breeding programs.     

Molecular cloning,sequence characterization,and expression analysis of C-type lectin (CTL) and ER-Golgi intermediate compartment 53-kDa protein (ERGIC-53) homologs from the freshwater prawn,Macrobrachium rosenbergii

Aquaculture International - Lectin protein families are diverse and multi-functional in crustaceans. The carbohydrate-binding domains (CRDs) of lectins recognize the molecular patterns associated...     

Optimization of Farmyard Manure to Substitute Mineral Fertilizer for Sustainable Productivity and Higher Carbon Sequestration Potential and Profitability under Gardenpea-French Bean Cropping System in the Indian Himalayas

Carbon sequestration potential (CSP) and sustainability of gardenpea-french bean cropping system was assessed with farmyard manure (FYM) application vis-à-vis mineral fertilization as recommended NPK (NPK) and integrated nutrient management practices (INM) after six years’ cropping in Indian Himalayas. Application of 20 tons FYM ha^?1 provided highest CSP (0.527 Mg C ha^?1 year^?1) in soil and sustainability index. With the help of quadratic equations, it was estimated that maximum profit (optimum yield) and turn over of invested money could be achieved with application of 20.0 and 15.6 t FYM ha^?1, respectively. Application of 5.9 and 8.9 tons FYM ha^?1 would substitute NPK and INM, respectively. Pod number plant^?1 was the most important yield-contributing attribute as found from principal component analysis. Pod yield could be modelled through multiple linear equation with help of yield attributes.     

Genetic variations in survival of rohu carp (Labeo rohita, Hamilton) after Aeromonas hydrophila infection in challenge tests

A challenge test against Aeromonas hydrophila was conducted using 2062 rohu carp (Labeo rohita) fingerlings obtained from 52 dams and 87 sires (87 full-sib families) of two year-classes (2003 and 2004). Attempts to establish a cohabitant challenge model were not successful. Therefore, fish were challenged by intraperitoneal injection with A. hydrophila in two replicate tanks per year-class, and dead fish were collected hourly. The mortality reached its peak at 16–22 h after challenge and had almost completely stopped after 58 h. The test was terminated after 382 h at which the average survival was 43.9 and 48.9% in the two 2003 year-class tanks, and 77.1 and 35.8% in the two 2004 year-class tanks. Heritability estimates for survival were obtained from sire and dam threshold models (THR) and sire and dam linear repeatability models (LINR). For both types of models the heritability estimates based on data from single tanks were not consistent. For both year-classes, data from one of the two challenged tanks demonstrated significant additive genetic variation in survival during the A. hydrophila infection, whereas the heritability estimates were not significantly different from zero for the other tank. Further, genetic correlation between survivals in the two replicate tanks in each year-class was not significantly different from zero. The differential results from the replicate tanks demonstrate that additional challenge test experiments are needed before firm conclusions can be drawn about the magnitude of additive genetic variation for survival to aeromonasis in rohu carp. A cohabitant challenge model that allows the testing of important defence mechanisms in the skin and mucous membranes of the fish might have been more appropriate. To establish a valid cohabitant challenge model for rohu carp should be given high priority.