Identification and enumeration of beta-hemolytic Listeria monocytogenes in naturally contaminated dairy products

A DNA probe was used to identify hemolytic Listeria monocytogenes in naturally contaminated dairy products: unpasteurized milk, ricotta cheese, and imported semisoft cheeses. Of 34 milk samples, 12 were suspected to contain hemolytic L. monocytogenes; 1 contained greater than 6000 viable organisms/g. The ricotta cheese, although temperature-abused, had a titer of 3.6 x 10(6) beta-hemolytic L. monocytogenes cells/g, whereas the semisoft cheeses reached a maximum of 5.6 x 10(6) cells/g. Pure cultures of L. monocytogenes isolated from both types of cheese were found positive by the CAMP test and the DNA probe.     

Impact of boron fertilization on boron fractions at different crop growth stages in cauliflower_cowpea_okra sequence in an inceptisols of North East India

Abstract

A field experiment was conducted at Horticultural Experimental Farm, Assam Agricultural University, Jorhat during the year 2015–17 to assess the impact of boron fertilization on dynamics of boron fractions in soil and crop yields in cauliflower–cowpea–okra cropping sequence. Five levels of boron (0, 0.5, 1.0, 1.5 and 2.0?kg ha^?1) along with the recommended dose of NPK fertilizer were applied in soil in cauliflower once in each 2 years (2015–17) of experimentation to assess the direct effect of boron fertilization, while cowpea and okra were grown as a suceeding test crop to study the residual effects of boron fertilization in the cropping sequence. Among the different levels of boron, the highest content of all the boron fractions in soil was recorded at rate of 2?kg B ha^?1 at different crop growth stages for all the three crops. Progressive decrease in content of all the boron fractions with crop ageing was noticed. The content of different boron fractions in soil follows the order readily soluble boron (RSB)<oxide bound boron (OXB)<organic bound boron (ORBB)<specifically adsorbed boron (SAB) <residual boron, respectively. The boron level of 2?kg B ha^?1 was found to prominent in increasing the yield in all the crops. In respect of contributions of different boron fractions to yield of crops, oxide bound boron(2.10) was found to be the highest contributor of cauliflower yield, while the residual boron (1.10), contributed the highest to cowpea yield and organic bound boron fraction (1.24) was found to be most prominent contributor of boron in leveraging okra yield.     

Sequential changes in tissue d-fructose-1,6-diphosphate aldolase activity in chickens experimentally infected with Borrelia anserina

Following experimental Borrelia anserina infection of chickens, aldolase activity increased in the proventriculus, heart and bone marrow but declined in the kidney and cervical spinal cord.     

Soil enzyme activities in dependence on tree litter and season of a social forest,Burdwan, India

The study was done to evaluate enzyme activities (amylase, cellulase and invertase) from the soils of different vegetation sites, with seasonal variation, of social forest, Burdwan, India. Study results showed significant lower enzymatic activities in the subsoil compared to those of the topsoil. The seasonal variations indicated that amylase, cellulase and invertase enzyme activities had reached peaks during the rainy seasons in different soil depths. Amylase activity was highest in Tectona litter containing soil in all seasons in both the soil layers. All the three enzyme activities have shown significant positive correlation with available nitrogen (p < 0.05) and available phosphorous (p < 0.05) during rainy season in both the soil depths. Correlation study revealed that soil organic carbon was positively correlated with cellulase and invertase activities except in the Anacardium vegetation site in the topsoil during rainy season. Irrespective of the seasons and the depths of soil, control site without vegetation showed much lower levels of organic carbon and enzyme activity compared to those of the experimental sites. Therefore, it is concluded that carbon transformation will be higher during rainy season in the vegetation sites of forest soil under such agroclimatic conditions.     

NTFPs and Their Commercialization Issues from the Perspective of Rural Livelihood and the State of Forest Resources: A Study of the Ranibundh Forest Range in West Bengal,India

Forests provide a source of livelihood to all classes of rural people, especially in tribal dominated areas. With the advent of joint forest management concepts and commercial earning prospects from non-timber forest products (NTFPs), it was expected that forests would be best preserved by the villagers who depend on them for a substantial part of their livelihoods. However, in the case of the Ranibundh block in the Bankura district, it was observed that the predominance of private agencies in marketing channels of NTFPs, together with risk of eviction, loss of customary right to access forest resources, low employment prospects, and lack of training about proper management of NTFPs have led to the failure in motivating the forest dwellers to prevent degradation of forest resources. It is suggested that government agencies, producer institutions, non-governmental organizations (NGOs), and other strong institutional entities can promote forest preservation when complemented by the granting of forest rights to rural people, the extension of training facilities, and alternative employment prospects.     

Soil carbon pools under long-term rice-wheat cropping system in Inceptisols of Indian Himalayas

Knowledge about soil organic carbon (SOC) stock and its allocation into different pools is important for global food and environmental security. Accordingly, an attempt is made in the present study to investigate into the dynamics of SOC pools i.e. total soil organic carbon (TOC), oxidisable organic carbon (OC) and its different fractions viz. very labile (C_VL), labile (C_L), less labile (C_LL) and non-labile (C_NL) in soils under a 26 years old long-term experiment with rice (Oryza sativa L) – wheat (Triticum aestivum L) cropping system on Inceptisols under humid agro-climatic region of India with different soil management practices (control, 100% recommended dose of NPK, and 50% recommended dose of NPK + 50% N through farmyard manure (FYM). Of the several pools analyzed, a higher proportion of C was found in labile pool followed by very labile, non-labile, and less labile ones constituting about 46, 26.5, 20 and 7.3% of the total organic C at surface soil. The NPK+FYM treatment was found to have higher SOC pools, lability index (LI), recalcitrance indices and stratification ratio as compared to others. Results indicated that balanced fertilization with inorganic and organics is important for maintaining overall sustainability of the rice-wheat system.     

Self-generated microbial population or cultured microflora – an important criterion toward development of an effective and economically viable road map for organic soil management

Huge depletion of soil microflora under conventional farming practice has become the primary contributory factor toward the present depletion of soil and crop productivity. Reconstitution of soil microbial dynamics has been identified as the only way out, but there has been a debate regarding the most effective pathway for soil rejuvenation i.e. whether to create the environment for natural proliferation or opt for inoculation of laboratory generated microbes. In this respect, a study was undertaken at Maud T.E. (Assam) under FAO-CFC-TBI Project, where bio-fertilizer (microbial inoculant, MI), vermicompost (organic food source, OF), vermicompost + bio-fertilizer (OF+MI), and Novcom compost (representing self-generated native microflora in the order of 10¹⁶c.f.u. along with organic food source, SNM); were taken as treatments for a yield target of 1500 kg made tea/ha. The highest crop yield (1500 kg ha^?1) along with high and consistent soil quality development was noted under SNM treatment; while MI influenced lowest yield (1268 kg ha^?1) and minimal soil response. Addition of the organic food source with cultured microbes (MI+OF) was found to improve crop performance (1427 kg ha^?1), but with 7.60 times higher cost (Rs. 39.97 kg^?1 made tea). Economic viability study indicated that except SNM, all other treatments were vulnerable toward crop loss or market downfall.     

Dominant Characteristics Between <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> and <Emphasis Type="Italic">Cyclotella</Emphasis> Sp. Accompanying Dilution Process in Eutrophic Lake

Although dilution of lake water has been used for improvement of water quality and algal blooms control, it has not necessarily succeeded to suppress the blooms. We hypothesized that the disappearance of algal blooms by dilution could be explained by flow regime, nutrient concentrations, and their interaction. This study investigated the effects of daily renewal rate (d), nitrogen (N) and phosphorus (P) concentration, and their interaction on the domination between Microcystis aeruginosa and Cyclotella sp. through a monoxenic culture experiment. The simulation model as functions of the N:P mass ratio and dilution rate (D) (calculated from d) was constructed, and the dominant characteristics of both species were predicted based on the model using parameters obtained in a monoculture experiment and our previous study. Results of monoxenic culture experiment revealed that M. aeruginosa dominated in all conditions (d = 5 or 15%; N = 1.0 or 2.5 or 5.0 mg-N L^?1; P = 0.1 or 0.5 mg-P L^?1) and the predicted cell densities were substantially correspondent to experimental data. Under various N:P ratios and D values, characteristics of domination for each species were predicted, indicating that Cyclotella sp. tended to be dominant under high P concentrations (P ≥ 0.36 mg-P L^?1) when the N:P ratio was less than 7.0, and M. aeruginosa could not form algal blooms at the N:P ratio ≤ 7.0 (N ≤ 0.7 mg-N L^?1). It was also suggested that the dilution rate leading to the Cyclotella sp. domination required 0.20 day^?1 or higher regardless of the N:P ratios.

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Graphical Abstract ? M. aeruginosa and Cyclotella sp. could be a superior competitor in nutrient-limited and nutrient-rich conditions, respectively. ? The simulation model in this study indicated that the predicted cell density and nutrient concentration were substantially correspondent to experimental data. ? The model predicted that Cyclotella sp. tended to be dominant at the P ≥ 0.36 mg-P L^?1 when the N:P ratio was less than 7.0, and M. aeruginosa could not form algal blooms at the N:P ratio ≤ 7.0 (N ≤ 0.7 mg-N L^?1).

     

Influence of nitrogen and plant density on the growth and seed production of common ragweed (Ambrosia artemisiifolia L.)

Common ragweed is an important annual weed in crop production, and is also considered to be a serious public health problem. Determination of common ragweed growth under various nitrogen (N) rate and plant density could aid the development of an integrated control program. Greenhouse and field experiments were conducted to determine the effects of N fertilizer and density on common ragweed growth and seed production. In the greenhouse study, the greatest shoot dry matter (SDM) plant^?1 was obtained with the 50 and 100?kg?N?ha^?1. In the field experiment, SDM plant^?1 in the low density plots responded favorably to the addition of medium and high levels of N compared to the field level of N. With increasing density, ragweed in higher density plots responded only with the highest N rate. The intensity of intraspecific competition increased with increasing density, thus total SDM plant^?1 was significantly reduced, regardless of N rate. Intraspecific competition also reduced the reproductive production of common ragweed where seed production decreased as plant density increased. Plants grown at higher density produced less seeds per plant basis; however, they produced a considerable number of seed on a per area land basis, which is important for the survival of the species and further expansion in agricultural land and non-crop areas. Common ragweed is a fast-growing species, capable of producing considerable biomass and seed at various pure stand densities and N rates. It also justifies the need for early season control to prevent seed production.