Structure and function of traditional agroforestry systems in the western Himalaya. II. Nutrient cycling

Budget of nutrient in plant and soil, and their rates of recycling in three types of traditional agroforestry systems in mid elevations of the western Himalaya were studied. Concentration of nitrogen and potassium was significantly higher in fruits and leaves than in branches, boles, and litter. Grewia optiva, an important fodder tree, was found to be rich in potassium, vegetable crops in nitrogen, and weeds in phosphorus. Maximum store of nutrients was estimated in aboveground biomass of agrihortisilvicultural system: nitrogen 532, phosphorus 40, potassium 461, calcium 400, and magnesium 298 kg/ha; it was closely followed by that in agrihorticultural system, and both these had sbout 2-fold higher nutrient stock as compared to agrisilvicultural system. In the case of the former two systems, considerable quantity of nutrients up to nitrogen 169, phosphorus 14, potassium 165, calcium 97, and magnesium 65 kg/ha, for example in agrihortisilvicultural system, was recycled through debris of crops and weeds, and tree leaf litter, while the recycling rate was almost half in agrisilvicultural system. Through ‘harvest’ potassium was depleted in the largest quantity from the system, followed by nitrogen, magnesium, calcium, and phosphorus; much higher loss occurred through agricultural and/or horticultural edible parts as compared to fuel and fodder biomass. For example, the loss through agricultural crops and horticultural fruits for nitrogen in agrihortisilvicultural system was up to 75 percent and 38 percent respectively of the total annual uptake. This heavy loss makes the system unstable from a nutrient point of view particularly for nitrogen and potassium until external inputs are added through organic and inorganic fertilizers. Agrihortisilvicultural system is remarkably efficient in view of biomass productivity for fuel, fodder and fruits, and also from nutrient point of view provided losses through harvest are compensated externally.     

巴氏消毒及冷藏温度作用下副溶血弧菌菌株失活异质性的比较

温度是影响细菌生长与失活的关键因素,在食品生产中常用来控制致病微生物潜在的风险。但由于不同菌株间个体的差异,细菌在相同温度作用下呈现出不同的失活趋势,这种行为方式称为菌株的失活异质性,容易导致微生物风险控制的不确定性和变异性。比较了19株副溶血性弧菌(16株临床菌株和3株环境菌株)在巴氏消毒温度(65℃)及冷链温度(10℃)作用下的失活情况,并结合Weibull模型,拟合相应的失活参数(t_R值),探究了不同菌株间的失活异质性。在65℃处理条件下,19株副溶血性弧菌的t_R值介于22.62～67.23 s,VPC-1为耐热性最强菌株,而VPC-10为耐热性最弱菌株,热失活参数t_R值最适的概率分布为Normal (44.82, 12.27)。在10℃条件下,t_R值介于113.96～371.38 h,VPC-3为耐冷性最强菌株,VPC-2为耐冷性最弱菌株,冷失活参数t_R值最适的概率分布为Loglogistic (51.45,148.88,4.67)。结果表明,副溶血性弧菌的热失活和冷失活间没有显著的相关性,菌株的失活异质性广泛存在于副溶血性弧菌之中,仅基于单一菌株进行失活模型的拟合,很难描述其整体的失活趋势。同时,初步构建了菌株失活异质性的随机模型,并使用概率分布代替了传统的失活参数。     

Targeted species substitution in giant freshwater prawn trade revealed by genotyping

This study presents the molecular barcoding results of giant freshwater prawns and allied products collected from inland landing centres, markets and stores of Vembanad Lake (Kerala state, India) which is recognized as a natural abode for Macrobrachium rosenbergii. Prawns collected from landing centres of the lake could be easily identified as the above with their large size and morphological characters. There were certain ‘alien’ prawns and prawn products (headless shell on, peeled and deveined) traded in the markets and stores of this region as M. rosenbergii. Genotyping of all these samples using COI and 16S rRNA gene sequences confirmed the speciation of individuals from inland landing centres as M. rosenbergii, ‘alien’ prawns and certain prawn products as M. malcolmsonii. To ensure the same and to detect the presence of any other congeners of genus Macrobrachium inhabiting Vembanad Lake, additional homologous COI and 16S rRNA sequences available in NCBI were acquired and incorporated for molecular analyses. Results generated from NJ tree and genetic distance data confirmed the trade of non‐indigenous Macrobrachium species M. malcolmsonii in Kerala for the first time and its use as a species substituent for M. rosenbergii.     

气单胞菌在不同食物接触表面的存活与交叉污染

为探讨气单胞菌在不同食物接触表面的存活状况,采用擦拭取样法测定气单胞菌于案板、刀具表面的恢复率,并将气单胞菌分别接种于洁净和被污染的案板、刀具表面,评定气单胞菌在不同介质表面、不同时间下的存活状况。根据恢复率和介质表面上气单胞菌存活实测值,采用@Risk软件对介质表面实时带菌量的期望值进行计算,并运用一级线性模型对气单胞菌存活特征曲线进行拟合。同时,以案板为交叉污染途径,对气单胞菌在介质表面的存活行为对交叉污染的影响进行了探讨。结果表明:采用擦拭取样法测得的气单胞菌从案板、刀具表面的恢复率的最佳分布拟合结果分别是Normal(0.66,0.15)和Normal(0.72,0.18);气单胞菌在被污染的介质表面存活的时间(7 h)长于其在洁净介质表面的存活时间(3 h或2.5 h),且一级线性模型可以较好地对气单胞菌存活曲线进行拟合(R20.88);蒙特卡罗模拟结果表明,忽略气单胞菌在食物接触表面的存活行为会高估其在厨房内的交叉污染水平。     

Inter simple sequence repeat (ISSR) polymorphism and its application in plant breeding

Inter simple sequence repeat (ISSR)-PCR is a technique, which involvesthe use of microsatellite sequences as primers in a polymerase chainreaction to generate multilocus markers. It is a simple and quick methodthat combines most of the advantages of microsatellites (SSRs) andamplified fragment length polymorphism (AFLP) to the universality ofrandom amplified polymorphic DNA (RAPD). ISSR markers are highlypolymorphic and are useful in studies on genetic diversity, phylogeny, genetagging, genome mapping and evolutionary biology. This review providesan overview of the details of the technique and its application in geneticsand plant breeding in a wide range of crop plants.     

Genetic diversity in common carp stocks assayed by random-amplified polymorphic DNA markers

The common carp (Cyprinus carpio L.) is one of the major aquaculture species, contributing nearly 35% to the inland fish production in Karnataka, India. Stocks collected from Hungary (2), Indonesia and Vietnam were assessed alongside two local stocks in a series of culture performance trials with the objective of setting up a base population for developing a breeding programme. The present study deals with the genetic divergence and polymorphism in these six stocks using random‐amplified polymorphic DNA (RAPD) markers. A total of 180 decamer random primers were screened for polymerase chain reaction (PCR) amplification (OPA 1‐20, OPB1‐20, OPC1‐20, OPD1‐20, OPE1‐20, OPF1‐20, OPG1‐20, OPP1‐20 and OPM1‐20). Eight primers were selected for analysis of common carp genotypes (OPA‐7, OPA‐20, OPB‐17, OPF‐10, OP F‐9, OPG‐4, OPG‐9 and OPP‐16). Out of 492 bands recorded, 57.1% were polymorphic. Stepwise regression analysis was carried out to find best combination markers affecting body weight (P<0.001). The results demonstrate major differences in the genetic structures between different stocks. Dendrogram data showed grouping of individuals according to stocks and corresponding data variables revealed the per cent homology within the stock and also found markers correlating to the body weight.     

Sialylation of Helicobacter bizzozeronii lipopolysaccharides modulates Toll-like receptor (TLR) 2 mediated response

Sialic acid in lipopolysaccharides (LPS) of mucosal pathogens is known to be an important virulence factor. Few strains of Helicobacter pylori express sialyl-Lewis-X and we have reported that human and canine Helicobacter bizzozeronii strains express sialyl-lactoseamine in their LPS. However, the role of sialyation of Helicobacter LPS in the interaction with the host cells is still unknown. In this study H. bizzozeronii LPS is shown to activate the TLR2 in a dose and strain dependent manner in the in vitro HEK-293 cells model expressing TLR2, but not the cells expressing TLR4. These results indicate that TLR2 is the specific receptor for H. bizzozzeronii LPS, as previously described for H. pylori. To further explore the role of sialylation of H. bizzozeronii LPS on TLR2 response, H. bizzozeronii Δhbs2 mutant strains deficient in sialyltransferase activity were constructed by homologous recombination. LPS from H. bizzozeronii Δhbs2 strains enhanced the NF-ĸB induction via TLR2 compared to the respective wild types, leading to the conclusion that the sialylation of H. bizzozeronii LPS in wild-type strains may modulate host immune response.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0133-4) contains supplementary material, which is available to authorized users.     

Insect antifeedant activity of tetranortriterpenoids from the Rutales. A perusal of structural relations

Structure-related insect antifeedant relationship of 56 limonoids (both natural and modified) from the plants belonging to the order Rutales was attempted considering substitution patterns, oxidation states, and hydrophobicity, as well as distant geometry derived through conformational analysis on molecular modeling. Orientation of the furan and hydroxylation at specific carbon sites have been shown to influence the antifeedancy against the fall armyworm, Spodoptera litura.     

Influence of spices on protein utilisation of winged bean (Prophocarpus tetragonolobus) and horsegram (Dolichos biflorus)

The influence of a mixture of eleven spices commonly consumed in India on the utilisation of protein from boiled winged bean (Psophocarpus tetragonolobus) and horsegram (Dolichos biflorus) was studied at 10 and 20 percent level of protein intake in experimental rats. Spices used in the mixture include red chillies (Capsicum annum), black pepper (Piper nigrum), coriander (Coriandrum sativum), cumin (Cuminum cyminum), garlic (Allium sativum), ajowan (Carum copticum), turmeric (Curcuma longa), caraway seeds (Carum carui) and fennel seeds (Foeniculum vulgare). Addition of this spice mixture at 1.5% level of the diet decreased the TD of both legumes, significantly only in the case of horsegram. A significant increase was observed in the BV of both the legumes at both levels of protein tested.