Evaluation of HYDRUS-2D model to simulate the loss of nitrate in subsurface controlled drainage in a physical model scale of paddy fields

Agriculture is a major source of nitrogen usage and release to environment. Due to the effect of water movement on solute transport, investigating the effect of different management scenarios of irrigation and drainage could be useful for reducing nitrate loss and environmental pollution. This study is a scientific attempt to assess the ability of HYDRUS-2D model to simulate the effect of subsurface controlled drainage on nitrate loss of paddy fields. So, two physical models with difference in depth of subsurface controlled drainage (40 and 60 cm) were constructed. The tanks were filled with loam silty soil texture and then transplanted rice. 90 kg/ha potassium nitrate fertilizer was added in two stages of rice growth. Mid-season drainage was applied 26 days after transplantation. After 17 days, drains were closed again and applied flooded irrigation with 5-cm water stagnant layer above soil surface. During experiment, nitrate concentration of drain water was measured. HYDRUS-2D was calibrated with measured data in 60 cm drain depth and validated with 40 cm drain depth. HYDRUS-2D could simulate nitrate concentration with the coefficient of determination 0.95 and 0.89 in calibration and validation stages, respectively. The comparison between the volume of drain water and nitrate concentration from the drains in the depths of 40 and 60 cm indicated lower nitrate load in depth of 40 cm. The results obtained proved that the presence of hardpan layer in depth of 25 cm rather than the absence of it causes increase in 3 % of average nitrate concentration and reduce in 17 % of water discharge.     

Growth parameters of whiteleg shrimp Litopenaeus vannamei and red seaweed Gracilaria corticata in integrated culturing method under zero water exchange system

Growth parameters of whiteleg shrimp Litopenaeus vannamei and red seaweed Gracilaria corticata were measured using integrated culturing method under zero‐water exchange system in a 45‐day period. A 2 × 3 factorial design was used with two levels of shrimp stocking densities and three levels of seaweed weight densities. G. corticata was cultured on a net tied to a round polyethylene frame. Culture tanks were filled with 750‐L filtered seawater. A 40‐W compact fluorescent lamp was hung over each tank to provide adequate and sufficient light for seaweed growth. Growth parameters of shrimp and seaweed such as specific growth rate (SGR), weight gained (WG) and average daily growth (ADG) were computed based on the initial and final weight of shrimp and seaweed. The maximum and minimum SGR of L. vannamei (1.97 and 1.69%/day) were observed in treatment S₁A₃ (25 shrimp/m² and 400 g seaweed/m²) and S₂A₁ (50 shrimp/m² without seaweed) respectively. The best survival rate (94.67 ± 1.33%), WG (129.9 ± 2.9%) and feed conversion ratio (1.67 ± 0.04) were also observed in treatment S₁A₃. The SGR of G.corticata in the treatment S₁A₃ (1.97 ± 0.00%/day) was significantly higher, compared to others. Strong positive correlations were obtained between the density of G. corticata and the growth parameters of L. vannamei. The red seaweed G. corticata could boost the growth parameters, survival rate and total production of L. vannamei under zero‐water exchange system.     

A basal area increment model for individual trees in mixed continuous cover forests in Iranian Caspian forests

The aim of this study was to develop and test a new basal area growth model in mixed species continuous cover forests in northern Iran.Weanalyzed 421 core samples from 6 main species in the forest area to develop our growth model.In each plot,we measured variables such as total tree height(m),diameter at breast height(DBH)(cm)and basal area of larger trees as cumulative basal areas of trees(GCUM)ofDBH[5 cm.The empirical data were analyzed using regression analysis.There was a statistically significant nonlinear function between the annual basal area increment,as the dependent variable,and the basal area of the individual trees and competition as explanatory variables.Reference area from the largest trees,was circular plot with area of 0.1 ha.GCUM was estimated for trees of DBH>5 cm.Furthermore,we investigated the dependencies of diameter growth of different species on stand density at different levels of competition,and diameter development of individual trees through time.The results indicate that competition caused by larger neighborhood trees has a negative effect on growth.In addition,the maximum diameter increment is affected by competition level.Therefore,the maximum diameter increment of species occurs when the trees are about 35–40 cm in dense-forest(40 to 0 m^2 per ha)and when the trees are about 60 to 70 cm in very dense forest(60 to 0 m^2 per ha)which is more likely to Caspian natural forests with high level density due to uneven-aged composition of stands.     

Evaluation of Outer Membrane Vesicles Obtained from Predominant Local Isolate of Bordetella pertussis as a Vaccine Candidate

Background:Pertussis is a current contagious bacterial disease caused by Bp. Given the prevalence of pertussis, development of new vaccines is important. This study was attempted to evaluate the expression of main virulence factors (PTX, PRN, and FHA) from Bp predominant strains and also compare the expression of these factors in the OMVs obtained from predominant circulating Bp isolate. Methods:The physicochemical features of the prepared OMVs were analyzed by electron microscopy and SDS-PAGE. The presence of the mentioned virulence factors was confirmed by Western blotting. BALB/c mice (n = 21) immunized with characterized OMVs were challenged intranasally with sublethal doses of Bp, to examine their protective capacity. Results:Electron microscopic examination of the OMVs indicated vesicles within the range of 40 to 200 nm. SDS-PAGE and Western blotting demonstrated the expression of all three main protective immunogens (PTX, PRN, and FHA), prevalent in the predominant, challenge, and vaccine strains, and OMVs of the predominant IR37 strain and BP134 vaccine strain. Significant differences were observed in lung bacterial counts between the immunized mice with OMV (30 CFU/lung) compared to the negative control group ((6 10⁴ CFU/lung; p < 0.001). In mice immunized with OMVs (3 µg), the number of lungs recovered colonies after five days dropped at least five orders of magnitude compared to the control group. Conclusion:OMVs obtained from circulating isolates with the predominant profile may constitute a highly promising vaccine quality. They also can be proposed as a potential basic material for the development of new pertussis vaccine candidate. Key Words: Bordetella pertussis, Vaccines, Virulence factors     

Transformation of the L-Asparaginase II Gene to Potato Hairy Roots for Production of Recombinant Protein

Journal of Crop Science and Biotechnology - Nowadays, transgenic plants are considered as an expression system for therapeutic recombinant proteins. One of the approaches to recombinant protein...     

Comparative effects of zinc-nano complexes,zinc-sulphate and zinc-methionine on performance in broiler chickens

1. Micronutrients, especially zinc, have an important role in normal metabolism and growth of broilers. Using novel technologies helps to synthesise novel zinc complexes to deliver this micronutrient more efficiently.

2. In the present study, the effects of different zinc complexes and nano complexes on broiler performance were compared. Broilers in 6 groups were given basal diet (without zinc) and basal diet supplemented with zinc-sulphate, zinc-methionine, zinc-nano-sulphate, zinc-nano-methionine and zinc-nano-max (that was synthesised based on nanochelating technology) at a concentration of 80 mg/kg of diet.

3. At 1–42 d of age, dietary zinc-nano-sulphate supplementation decreased weight gain and feed intake. However, feed conversion ratio was not influenced by treatments. Carcass yield (%) of birds in the zinc-nano-sulphate and control groups were dramatically reduced at 42 d of age and abdominal fat (%) increased in these groups.

4. Relative to the control group, the antibody titre, spleen and bursa of Fabricius (%) were significantly higher in groups supplemented with zinc. Heterophil (%) was also significantly higher in the zinc-nano-methionine group in blood on d 42 compared to the control, zinc-sulphate and zinc-nano-sulphate.

5. Compared to the controls, the mean malondialdehyde content in thigh tissue was significantly reduced in groups supplemented with zinc at the time 0, 50, 100 and 150 min after oxidation.

6. Tibia zinc concentration in nanoparticle zinc samples was significantly higher relative to the control and zinc-sulphate groups.

7. Taken together, our data indicate that delivery of zinc in the structure of zinc-nano-methionine and zinc-nano-max at concentrations of 80 mg/kg of diet improves growth performance. However, dietary zinc-nano-sulphate decreased growth performance in broilers.

     

Interpreting genotype × environment interactions for durum wheat grain yields using nonparametric methods

The objective of this study was to compare nonparametric stability procedures and apply different nonparametric tests for genotype × environment (G × E) interactions on grain yields of 15 durum wheat genotypes selected from Iran/ICARDA joint project grown in 12 environments during 2004–2006 in Iran. Results of nonparametric tests of G × E interaction and a combined ANOVA across environments indicated the presence of both crossover and noncrossover interactions, and genotypes varied significantly for grain yield. In this study, high values of TOP (proportion of environments in which a genotype ranked in the top third) and low values of sum of ranks of mean grain yield and Shukla’s stability variance (rank-sum) were associated with high mean yield. The other nonparametric stability methods were not positively correlated with mean yield but they characterized a static concept of stability. The results of correlation analysis indicated that only TOP and rank-sum methods would be useful for simultaneous selection for high yield and stability. These two methods identified lines Mrb3/Mna-1, Syrian-4 and Mna-1/Rfm-7 as genotypes with dynamic stability and wide adaptation. According to static stability parameters, the genotypes 12A-Mar8081 and 19A-Mar8081 with lowest grain yield were selected as genotypes with the highest stability.     

The genetics of maize (Zea mays L.) growing at low temperatures II. Harvesting time,number of kernels and plant height at maturity

Summary A set of 11 inbred lines of grain maize and generations derived from them were grown at a latitude further north than the generally accepted limit of the crop in the U.K. Analyses of variance for harvesting time, number of kernels and final plant height showed significant differences between the inbred lines and between their F₁, F₂ and backcross generations.A- and C-scaling tests or the joint scaling test were used to analyse the means of parents, F₁, F₂ and the two backcross generations for 8 reciprocal crosses.These tests showed that for all the crosses the addivite-dominance models were adequate for the characters. i.e. there was little or no evidence of non-allelic interactions.There was some evidence for heterosis for number of kernels and plant height, that of number of kernels being particularly impressive.     

The efficacy and safety of long-term Helicobacter species quadruple therapy in asymptomatic cats with naturally acquired infection

Owing to rising drug-resistant Helicobacter species infections in people and animals, currently therapies are losing their efficacy; therefore, regimens efficacious in the presence of drug resistance are needed. This study assessed the efficacy and safety of a 14-day quadruple Helicobacter species therapy in cats with naturally acquired infection. Thirteen asymptomatic adult stray cats with Helicobacter species infection (identified by analysis of gastric biopsies using polymerase chain reaction and Helicobacter-specific primers) received omeprazole 0.7mg/kg q 8h plus amoxicillin 20mg/kg q 12h, metronidazole 20mg/kg q 12h and clarithromycin 7.5mg/kg q 12h, for 14 days. Second molecular analysis of gastric biopsies revealed persistence of Helicobacter species DNA in four cats that were negative on quantitative urease testing, cytology and histopathology. Our results suggest that antibiotic regimens that are effective against Helicobacter pylori in people cannot eradicate Helicobacter species in cats with naturally acquired infection, although transient suppression may occur.     

Isolation and identification of bubaline herpesvirus 1 (BuHV-1) from latently infected water buffalo (Bubalus bubalis) from Iran

In order to isolate buffaloes herpesvirus 1 (BuHV-1) from latently infected water buffalo (Bubalus bubalis), 16 buffalo heifers were selected from a herd. At first, animals were bled and their sera were tested by virus neutralization (VN) test, using bovine herpesvirus 1 (BoHV-1). According to the results of VN test and dexamethasone injection (0.1 mg/kg BW) for 5 consecutive days, the examined buffaloes were divided into 4 groups. Vaginal and nasal swabs were daily collected from all buffaloes from day 0 to 10 days later. Based on the cytopathic effects in cell culture, a herpesvirus was isolated only from nasal swabs of three seropositive buffaloes which they had received dexamethasone. The nasal swabs of these three buffaloes were also positive in PCR, using primers specific for ruminant herpesviruses gD gene. The identity of the isolated viruses was determined according to partial amino acid sequences of gD, deduced from the nucleotide sequences of the PCR products. On the basis of sequence alignment, phylogenetic analysis, and genetic distances, the three buffalo virus isolates were more closely related to BuHV-1 and BoHV-5 than to BoHV-1.