Identification of unique DNA sequences present in highly virulent 2009 Alabama isolates of Aeromonas hydrophila

In 2009, a disease outbreak caused by Aeromonas hydrophila occurred in 48 catfish farms in West Alabama, causing an estimated loss of more than 3 million pounds of food size channel catfish. Virulence studies have revealed that the 2009 isolates of A. hydrophila are at least 200-fold more virulent than a 1998 Alabama isolate AL98-C1B. However, up to now, no molecular markers have been identified to differentiate the highly virulent 2009 isolates from other isolates of A. hydrophila. To understand the genetic differences between the highly virulent 2009 isolates and the less virulent AL98-C1B at molecular level, PCR-select bacterial genome subtractive hybridization was used in this study. A total of 96 clones were selected from the subtractive genomic DNA library. Sequencing results revealed that the 96 clones represented 64 unique A. hydrophila sequences. Of the 64 sequences, three (hypothetical protein XAUC_13870, structural toxin protein RtxA, and putative methyltransferase) were confirmed to be present in the three virulent 2009 Alabama isolates but absent in the less virulent AL98-C1B. Using genomic DNAs from nine field isolates of A. hydrophila with different virulence as templates, two sequences (hypothetical protein XAUC_13870 and putative methyltransferase) were found to be only present in highly virulent A. hydrophila isolates, but absent in avirulent isolates.     

Effect of dietary protein on intake,nutrients utilization,nitrogen balance,blood metabolites,growth and puberty in growing Bhadawari buffalo (Bubalus bubalis) heifers

Fifteen Bhadawari buffalo heifers of 207?±?9.78 kg mean body weight were randomly distributed into three dietary groups to evaluate the effect of protein level on nutrient utilization, nitrogen (N) balance, growth rate, blood metabolites, and puberty. All animals were offered wheat straw-berseem diets supplemented with concentrate mixtures of similar energy (2.7 Mcal/kg) and different protein levels (14.3–22 %). Animals of standard-protein group (SPG) were offered protein and energy as per requirement, while animals of low-protein group (LPG) and high-protein group (HPG) were fed 20 % less and 20 % more protein, respectively, than SPG. Feed dry matter (DM) and metabolizable energy (ME) intake (% body wt. and g/kg w^0.75) were similar for all three diets; however, the crude protein (CP) and digestible crude protein (DCP) intake on percent body weight and per kilogram metabolic weight was higher (P?<?0.05) in HPG than in SPG or LPG. Digestibility of CP, cellulose, and hemicellulose was higher (P?<?0.05) in HPG versus LPG. Fecal N excretion was similar, while urinary N excretion was highest (P?<?0.05) in HPG (74.83 g/day) compared with SPG (50.03 g/day) and LPG (47.88 g/day), which resulted in lower N retention in HPG than in the other dietary groups. Level of dietary N had no effect on blood metabolites viz. glucose, urea, and N. Digestible energy (DE) and ME contents of diets were identical, while DCP contents were higher (P?<?0.05) in HPG than in LPG. Feed and nutrient (CP and ME) conversion efficiency to produce a unit kilogram weight gain was identical among the dietary groups. Dietary protein level had no effect on the heifer’s weight and age at puberty. The mean growth rate of heifers at 240 days was higher (P?>?0.05) in SPG (330.8 g/day) than in LPG (296.7 g/day), while the animals gained more weight in January to March months and the lowest weight in May to July months. Protein level had no effect on conception rate of heifers. Results revealed that 20 % higher or less protein than the ICAR requirement had no significant (P?>?0.05) on feed intake, nutrient conversion efficiency for weight gain, heifer growth, and puberty; however, 20 % more protein increased urinary N loss.

     

Drip irrigation and nitrogen fertilization alter phenological development and yield of spring maize (Zea mays L.) under semi-arid conditions

Abstract

Maize response to deficit water and nitrogen for assessing phenological development and yield was studied under semi-arid conditions. Experiment consisting three drip irrigation levels, replenish 60 (DI₆₀), 80 (DI₈₀) and 100 percent (DI₁₀₀) of cumulative pan evaporation, and four nitrogen doses 50 (RN₅₀), 75 (RN₇₅), 100 (RN₁₀₀) and 125 (RN₁₂₅) per cent of recommended nitrogen. A Furrow irrigated treatment was kept as control/check. Significant earliness in visibility of collar of 8^th leaf, tasseling, silking and significant delay in dough stage and physiological maturity was recorded under well water treatment DI₁₀₀ as compared to DI₆₀. Days to collar of 8^th leaf, tasseling and silking had significant negative correlation, and duration of yield formation phase and days to physiological maturity had significant positive correlation with grain yield. Higher DM production, longer yield formation phase and late physiological maturity led to significantly higher grain yield under DI₁₀₀. In case of nitrogen levels, phonological characteristics like collar of 8^th leaf, tasseling and silking were significantly delayed, and dough stage and physiological maturity were advanced under nitrogen deficit treatment RN₅₀ as compared to RN₁₀₀ and RN₁₂₅. Significantly higher dry matter production and longer yield formation phase observed led to significant higher SCY under RN₁₀₀ and RN₁₂₅ as compared to RN₅₀. Yield formation phase was significantly longer under drip irrigated crop as compared to control during 2^nd year of study. Crop phenological development significantly affected by drip irrigation regimes and nitrogen levels, and there was significant correlation between phenological stages development and grain yield.     

Multi-Block Data Modeling for Characterization of Soil Contamination: A Case Study

Multi-block (heavy metals, pesticides, physico-chemical parameters) data set pertaining to the soils of alluvium region in Indo-Gangetic plains was analyzed using principal component analysis (PCA) and multiple factor analysis (MFA) methods to delineate the contaminated sites and to identify the possible contamination sources in the study region. In normal PCA, the first three factors were dominated mainly by heavy metals, pesticides and physico-chemical variables, respectively, thus identifying samples/sites contaminated with these. The MFA results, due to its unique weighting scheme of variables of different blocks extracted, to more realistic information about the spatial distribution of samples and relationships among the variables. MFA minimized the influence of variables of one single block on the first few components, allowing variables of all blocks equally to share the common MFA space. This resulted in delineating the sites/regions contaminated with variables (Al, Co, Cu, Mn, Ni, Pb, V, Na, SO₄, aldrin, lindane, HCB, HCH, DDT, and endosulfan) of all the blocks, rather than by particular block variables as in case of normal PCA, where, the variables of single block dominate the first factors, suppressing other block variables. MFA which can be considered as a method for standardization of the multi-block variables was successfully applied to the three block data set of soils.     

Direct antifungal activity of tiadinil,a systemic acquired resistance inducer,and thymol formulations on <Emphasis Type="Italic">Stagonosporopsis citrulli</Emphasis> and control of watermelon gummy stem blight

This study evaluated the direct antifungal activity of tiadinil [N-(3-chloro-4-methylphenyl)-4-methyl-1,2,3-thiadiazole-5-carboxamide], a systemic acquired resistance (SAR) inducer and two formulations of thymol (thymol I and thymol II) against Stagonosporopsis citrulli, the causal agent of gummy stem blight (GSB) disease of watermelon. Tiadinil, thymol I and thymol II completely inhibited the mycelial growth of S. citrulli in vitro at ≥?100 ppm. Conidial germination and germ tube elongation were completely inhibited by tiadinil at ≥?2000 ppm and by thymol-based formulations at ≥?100 ppm. A single foliar application of tiadinil at ≥?10 ppm or a single application of thymol I and II at ≥?1 ppm, 48 h before or after pathogen inoculation, significantly reduced disease severity of watermelon seedlings inoculated with 10⁵/ml conidial suspension of S. citrulli, compared to respective nontreated controls. Plants treated with foliar application of tiadinil at ≥?1000 ppm before pathogen inoculation had significantly lower disease severity than plants that received an equivalent drench application. The efficacy of foliar application of tiadinil was affected by concentration and frequency of application. The study suggests direct antifungal activity of tiadinil, indicating a new mode of action of tiadinil against GSB disease of watermelon. The study also demonstrated direct antifungal action of thymol, a formulated active compound of essential oils, against S. citrulli and GSB disease of watermelon.     

Impact of organic manures with and without mineral fertilizers on soil chemical and biological properties under tropical conditions

Soils receiving organic manures with and without chemical fertilizers for the last 7 yr with pearlmillet–wheat cropping sequence were compared for soil chemical and biological properties. The application of farmyard manure, poultry manure, and sugarcane filter cake alone or in combination with chemical fertilizers improved the soil organic C, total N, P, and K status. The increase in soil microbial‐biomass C and N was observed in soils receiving organic manures only or with the combined application of organic manures and chemical fertilizers compared to soils receiving chemical fertilizers only. Basal and glucose‐induced respiration, potentially mineralizable N, and arginine ammonification were higher in soils amended with organic manures with or without chemical fertilizers, indicating that more active microflora is associated with organic and integrated system using organic manures and chemical fertilizers together which is important for nutrient cycling.     

Selection of soil physical quality indicators in relation to soil erodibility

Soil quality indices based on soil characteristics can be used to assess the sustainability of soil and to assist in soil management decisions. Principal component analysis (PCA) technique was used to identify dominant soil characteristics in relation to soil erodibility in watersheds of submontane Punjab (India). Soil physical and chemical characteristics were evaluated for four locations with four land uses at each location whereas runoff, soil loss and soil erodibility were determined at two locations under natural rainfall conditions and at four locations under simulated rainfall conditions. PCA was performed on 22 physical and chemical soil characteristics, which grouped these soil characteristics into five distinct principal components (PCs). These five PCs namely soil hydraulic factor, density factor, structural factor, sand factor and cation factor, explained 86% variability in data. These PCs also explained 86, 96 and 93% variability under natural rainfall conditions and 75, 76 and 77% variability under simulated rainfall conditions in relation to runoff, soil loss and soil erodibility, respectively. Soil total organic carbon content can be considered as dynamic soil physical quality indicator and can be used to monitor temporal and spatial changes in soil quality.     

Genetics of resistance to Sesamia inferens infestation and its correlation with yield in maize

Sesamia inferens (Walker) causes 25.7–78.9% losses in maize production in South and South‐East Asia. The genetic basis of host plant resistance is the prerequisite for resistance breeding. Twenty‐four populations derived from S. inferens resistant × susceptible inbreds were used to study the genetic regulation of resistance to S. inferens in maize, to determine the importance of genetic effects through generation mean analysis (GMA) and to understand correlation between resistance and yield. Resistant and susceptible inbreds differed significantly in leaf and stem injury ratings (LSIR), a measure of host plant resistance. Mean LSIR range among resistant and susceptible parents was 2.15–2.55 and 7.83–8.22, respectively. The broad‐sense heritability ranged from 0.40 to 0.71, and the mean number of effective factors ranged from 1.9 to 2.6. The resistance against S. inferens was largely governed by additive × additive (i), followed by dominance (d) and additive (a) gene effects. Significant negative correlation (?0.27 to ?0.96) was observed between LSIR and yield. The findings suggest reciprocal recurrent selection for development of new inbreds with resistance followed by their involvement in hybrid development to exploit additive and non‐additive gene effects/variance.     

Microbial biomass and activity indices after organic substrate addition to a selenium-contaminated soil

High concentrations of Se in soil might have negative effects on microorganisms. For this reason, the effect of organic substrate addition (glucose + maize straw) on Se volatilisation in relation to changes in microbial biomass and activity indices was investigated using an artificially Se-contaminated soil. Microbial biomass N was reduced on average by more than 50% after substrate addition, but adenylate energy charge (AEC) and metabolic quotient qCO₂ were both increased. The Se content decreased by nearly 30% only with the addition of the organic substrate at 25°C. No significant Se loss occurred without substrate at 25°C or with substrate at 5°C. In the two treatments with substrate addition, the substrate-derived CO₂ evolution was about 30% lower with Se addition than without. In contrast, Se had no effect on any of the other soil microbial indices analysed, i.e. microbial biomass C, microbial biomass N, adenosine triphosphate (ATP), AEC, ATP-to-microbial biomass C, and qCO₂.