Solid-Phase Extraction Embedded Dialysis (SPEED), an Innovative Procedure for the Investigation of Microbial Specialized Metabolites

Solid-phase extraction embedded dialysis (SPEED technology) is an innovative procedure developed to physically separate in-situ, during the cultivation, the mycelium of filament forming microorganisms, such as actinomycetes and fungi, and the XAD-16 resin used to trap the secreted specialized metabolites. SPEED consists of an external nylon cloth and an internal dialysis tube containing the XAD resin. The dialysis barrier selects the molecular weight of the trapped compounds, and prevents the aggregation of biomass or macromolecules on the XAD beads. The external nylon promotes the formation of a microbial biofilm, making SPEED a biofilm supported cultivation process. SPEED technology was applied to the marine Streptomyces albidoflavus 19-S21, isolated from a core of a submerged Kopara sampled at 20 m from the border of a saltwater pond. The chemical space of this strain was investigated effectively using a dereplication strategy based on molecular networking and in-depth chemical analysis. The results highlight the impact of culture support on the molecular profile of Streptomyces albidoflavus 19-S21 secondary metabolites.     

Dietary zinc requirement of Siberian sturgeon (Acipenser baerii,Brandt 1869) juveniles,based on the growth performance and blood parameters

International Aquatic Research - This study investigated the effect of dietary Zn levels on growth performance, feed utilization, and hematological parameters of juvenile Siberian sturgeon...     

Effect of apple peel extract as natural antioxidant on lipid and protein oxidation of rainbow trout (Oncorhynchus mykiss) mince

International Aquatic Research - The aim of this study was to use apple peel extract (APE) as antioxidant for inhibition of lipid and protein oxidation in rainbow trout (Oncorhynchus mykiss) mince...     

Sulfur uptake and translocation in maize (zea mays) grown in a high pH soil treated with elemental sulfur

A glasshouse experiment was conducted to elucidate the influence of elemental sulfur (S) application rates (0, 0.5, 1.0, and 2.0 g S kg^?1 soil) on the release and uptake of S at 0, 20, and 40 days after incubation. Results showed that there was a progressive upward trend in maize leaves, stem, and root S content with application of elemental S. However, maize production followed a nonlinear model. Plants grown in untreated soils suffer from S deficiency and addition of elemental S at a rate of 0.5 g S kg^?1 soil alleviated S deficiency. The decrease in maize performance due to the highest S application rate was not related to S toxicity. The greatest leave, stem, and root productions were obtained at S concentrations of 0.41, 0.58, and 0.2%, respectively. Overall, application of elemental S at a rate of 0.5 g S kg^?1 soil is recommended for maize performance improvement.     

Molecular genotyping and epidemiology of Mycobacterium bovis strains obtained from cattle in Iran

Restriction fragment length polymorphism (RFLP) genotyping was employed to analyze the population genetics of Mycobacterium bovis in Iran. One hundred and twenty-three isolates collected from slaughtered tuberculosis-suspect cattle and one clinically asymptomatic buffalo were subjected to RFLP analysis with probes of the polymorphic GC-rich sequence (PGRS) and the direct repeat sequence (DR) using DNA digested with PvuII and AluI. All these methods detected a large homogeneous population in which only a few isolates had variant genotypes. Only AluI-based RFLPs of both the PGRS and DR sequences were able to clearly differentiate between BCG and field strains of M. bovis. As in previous reports, these findings seem to reflect a recent dispersal of one or a few strains in Iran following the substantial expansion of Holstein-Friesian cattle over the last few decades.     

EVALUATION OF FATTY INFILTRATION OF THE LIVER IN DAIRY CATTLE THROUGH DIGITAL ANALYSIS OF HEPATIC ULTRASONOGRAMS

Ultrasonography of the liver of 49 Holstein-Friesian cows was performed, liver specimens were taken, examined microscopically and the fatty occupying rate (FOR) was calculated. Echoes from the hepatic B-mode ultrasonograms were quantified as histogram mean (Emean) and histogram mode (Emode) of echo amplitudes within various areas at a depth of 1–9 cm from the hepatic surface. Of the 49 animals, 26 had a normal liver and 23 had fatty infiltration of the liver, diagnosed through histopathological examination. Fatty occupying rate ranged from 1.7 to 64.5%, with 11 animals having 1–15% FOR (mild fatty infiltration), 6 having 15.1–30% FOR (moderate fatty infiltration) and 6 having > 30% FOR (severe fatty infiltration). At 1 cm, severe fatty infiltration had higher Emean and Emode than normal liver (p < 0.05). At 7 cm and 9 cm, moderate and severe fatty infiltration had lower Emeans and Emodes than normal liver (p < 0.001). The results suggest that digital analysis of hepatic ultrasonogram can be useful in the evaluation of the degree of fatty infiltration of the liver in dairy cattle.     

The role of dietary L‐ascorbyl‐2‐polyphosphate on the growth and physiological functions of beluga,Huso huso (Linnaeus, 1758)

Effects of dietary ascorbic acid (AA) supplementation were carried out on growth performance and physiological indices in juvenile beluga Huso huso fed different levels of dietary L‐ascorbyl‐2‐polyphosphate as AA source consisting of 0 (control), 100, 200, 400, 800 and 1600 mg AA kg^?1 diet for 16 weeks. No significant differences were found in growth performances between treated groups except for condition factor. Using AA caused significant differences in haemoglobin, number of red blood cells, white blood cells, aspartate aminotranspherase and lactate dehydrogenase, while no significant difference was found in haematocrit, mean corpuscular haemoglobin concentration, differential white blood cells count and alkaline phosphatase activity at the end of the experiment. Lysozyme activity after 8 weeks was significantly affected by dietary treatments with the lowest value in fish fed control diet, but not at completion of 16‐week feeding trial. Liver AA concentration showed a significant increase in correlation with dietary AA increase. Air exposure stress test showed significant differences among the treatments in case of cortisol and glucose concentrations. Also between pre‐ and post stress, significant changes were observed in some of treatments. The lowest and highest levels of cortisol were 9.2 ± 3 (in 200 mg kg^?1) and 16.8 ± 5.1 ng mL^?1 (in control), 6 h post stress (P < 0.05) respectively. Also, the lowest and highest levels of glucose were measured in fish fed 200 and 800 mg AA kg^?1 respectively. The obtained results showed that most growth parameters were not affected by dietary AA, but some physiological and immunological parameters of this species were influenced by this vitamin. We suggest that under rearing conditions, AA should be added to the diet especially during early life stages for improving health status and resistance to stressors.     

Nitrate leaching in a silage maize field under different irrigation and nitrogen fertilizer rates

Quantification of the interactive effects of nitrogen (N) and water on nitrate (NO₃) loss provides an important insight for more effective N and water management. The goal of this study was to evaluate the effect of different irrigation and nitrogen fertilizer levels on nitrate-nitrogen (NO₃-N) leaching in a silage maize field. The experiment included four irrigation levels (0.7, 0.85, 1.0, and 1.13 of soil moisture depletion, SMD) and three N fertilization levels (0, 142, and 189 kg N ha⁻¹), with three replications. Ceramic suction cups were used to extract soil solution at 30 and 60 cm soil depths for all 36 experimental plots. Soil NO₃-N content of 0-30 and 30-60-cm layers were evaluated at planting and harvest maturity. Total N uptake (NU) by the crop was also determined. Maximum NO₃-N leaching out of the 60-cm soil layer was 8.43 kg N ha⁻¹, for the 142 kg N ha⁻¹ and over irrigation (1.13 SMD) treatment. The minimum and maximum seasonal average NO₃ concentration at the 60 cm depth was 46 and 138 mg l⁻¹, respectively. Based on our findings, it is possible to control NO₃ leaching out of the root zone during the growing season with a proper combination of irrigation and fertilizer management.     

Effect of diet composition on growth performance,hepatic metabolism and antioxidant activities in Siberian sturgeon (<Emphasis Type="Italic">Acipenser</Emphasis><Emphasis Type="Italic">baerii</Emphasis>, Brandt, 1869) submitted to starvation and refeeding

Many fish species undergo natural starvation periods. Adaptation to starvation is possible through the activation of behavioral, biochemical and physiological mechanisms. Knowledge of the effect of dietary nutrients on the intermediary metabolism during starvation and refeeding can be useful to improve fish health and optimize aquaculture production. To analyze the effect of dietary nutrients on liver metabolism of Siberian sturgeon (Acipenser baerii) submitted to starvation and refeeding, four isoenergetic diets differing in nutrient composition were designed: LP-St (38 % protein, 12 % lipid, 36 % carbohydrate), HP-St (44 % protein, 10 % lipid, 30 % carbohydrate), LP-L (38 % protein, 18 % lipid, 25 % carbohydrate) and HP-L (44 % protein, 16 % lipid, 22 % carbohydrate). Four groups of fish were fed 3 weeks to satiety with the corresponding diet, starved for 2 weeks and then refeed 5 weeks to satiety on the same diet. Starvation mobilized the hepatic lipid store to a greater extent than glycogen. Starvation increased superoxide dismutase activity irrespective of the diet, while low protein diets (LP-St and LP-L) increased catalase activity. The oxidative damage decreased after 5 weeks of refeeding. Refeeding the starved fish on the HP-St diet promoted the greatest growth performance. In addition to reporting for the first time the effect of diet composition on growth, liver composition and antioxidant activities in Siberian sturgeon submitted to starvation and refeeding, our findings suggest that refeeding on HP-St diet stimulated the use of dietary carbohydrates and allowed a protein sparing effect in Siberian sturgeon.     

Nonparametric phenotypic stability analysis in advanced barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) genotypes

The development of genotypes with adaptation to a wide range of environments is one of the most important goals of plant breeding programs. In order to compare nonparametric stability measures and to identify promising high-yield and stable barley (Hordeum vulgare L.), 20 barley genotypes selected from the Iran/ICARDA joint project and grown in nine environments during 2009-11 in Iran. Four nonparametric statistical tests of significance for genotype × environment (GE) interaction and 10 nonparametric measures of stability were used to identify stable genotypes in nine environments. Results of nonparametric tests of G×E interaction (Kubinger, Hildebrand, and Kroon/ Laan) and a combined ANOVA across environments, indicated the presence of both crossover and non-crossover interactions. Also, only TOP and rank-sum values were positively associated with high yield. Thus, in the simultaneous selection for high yield and stability, only the rank-sum and TOP methods were useful in terms of the principal component analysis results, and correlation analysis of nonparametric stability statistics and yield. According to these stability parameters (TOP and rank-sum), three genotypes (G13, G12, and G17) were the most stable for grain yield. The results also revealed that based on nonparametric test results, stability could be classified into three groups, according to agronomic and biological concepts of stability.