Single nucleotide polymorphisms in candidate genes are significantly associated with resistance to Haemonchus contortus infection in goats

Background: Haemonchosis is a major economic problem in goat production in humid, tropical and subtropical regions. The disease is caused by an abomasal nematode, Haemonchus contortus, which is highly pathogenic in small ruminants. The aim of this study was to identifying single-nucleotide polymorphisms(SNP) that were associated with fecal egg counts(FEC) and could be used as markers to identify resistance to H. contortus in goats.Results: Ten novel variants in the CI TA, ATP2 A3, HSPA8, STAT5 B, ESYT1, and SERPING1 genes were associated with FEC in goats with a nominal significance level of P 0.05. Two missense mutation in the exon region of the caprine CI TA gene resulted in replacement of arginine with cysteine at position 9473550(R9473550 C) and aspartic acid with glutamic acid at position 9473870(D9473870 E). Chinese goat breeds had significantly higher FEC than Bangladeshi goat breeds within their respective genotypes. Polymorphism information content(PIC), effective al ele number(Ne), and heterozygosity(He)were greatest for the STAT5 B_197_A G SNP locus in al goat breeds. Pairwise coefficients of linkage disequilibrium(D′, r~2)revealed complete LD(r~2= 1) between significant SNP polymorphisms in CI TA and SERPING1 and strong LD(r~2= 0.93 and0.98) between polymorphisms in HSPA8 and ATP2 A3, respectively. Correlation coefficient(r) between FEC and body weight(BW) was significantly positive(r = 0.56***, P 0.001) but that between FEC and packed cel volume(PCV) was negatively significant(r =-0.47**, P 0.01) in the total population of goats. On the other hand, correlation coefficient(r)between BW and PCV was not significant in total population of goats. Association analysis revealed that haplotypes within ATP2 A3, HSPA8, and SERPING1 were significantly associated with FEC. Quantitative real-time PCR revealed that the relative expression of m RNA was higher(P 0.001) for resistant, compared to susceptible, groups of goats for al candidate genes except CI TA.Conclusions: This study identified SNP markers that can potential y be used in marker-assisted selection programs to develop goat breeds that are resistant to H. contortus.     

Diversity of chemical composition, dry matter intake, in vivo digestibility and in situ dry matter degradability of oat hay (Avena sativa)

Diversity of chemical composition, in vivo digestibility and in situ dry matter degradability of oat hay (Avena sativa) were studied. Oat hay samples obtained from 22 batches imported were analyzed for chemical composition. The result showed a wide range of variations in crude protein (3.9–8.8%, on a dry matter basis), crude fiber (22.1–35.2%), nitrogen free extract (50.0–66.0%), organic cellular contents (23.4–40.0%), organic cell wall (53.1–70.8%), organic a (4.1–9.8%), organic b (49.0–63.8%) fractions and the estimated total digestible nutrients (50.3–63.8%) from the organic components. Of these, four oat hay samples were used for the measurement of dry matter intake, in vivo digestibility and in situ dry matter degradability in sheep. Significant differences were observed for the dry matter intake, in vivo digestibility of dry matter, crude protein, crude fiber and nitrogen free extract, dry matter disappearance at 48 h and effective degradability at k = 0.05 h^?1 of the samples (P < 0.05). The results revealed a wide range of diversity of nutritional quality of the imported oat hay that could have an affect on production potential in animals.     

Virulence, resistance to magainin II, and expression of pectate lyase are controlled by the PhoP-PhoQ two-component regulatory system responding to pH and magnesium in Erwinia chrysanthemi 3937

Marker-exchanged mutants of phoP and phoQ of Erwinia chrysanthemi (Ech) strain 3937 became more sensitive to the cationic antimicrobial peptide (CAMP) magainin II than did the wild type at a low Mg²⁺ concentration and at either acidic or neutral pH. At high Mg²⁺ and acidic pH, only the phoQ mutant, but not the phoP mutant, became more sensitive to magainin II than did the wild type; both mutants were more sensitive at neutral pH. The hyperinduction of Pel synthesis in medium containing plant extracts and polygalacturonic acid (PGA) was confirmed in the wild type but not in the mutants at low Mg²⁺ and neutral pH. However, Pel was hyperinduced at high Mg²⁺ and neutral pH in these mutants but not in the wild type. Maceration was also greatly reduced by these mutants compared to the wild type when the inoculum was precultured and then resuspended in the medium with low Mg²⁺ at neutral pH. However, when bacteria were precultured and resuspended in the medium with high Mg²⁺ at neutral pH, severe maceration was observed in these mutants but not in the wild type. Thus, at low Mg²⁺, PhoP-PhoQ TCS seems to be stimulated for maceration and the hyperinduction of Pel synthesis. At high Mg²⁺, however, PhoP-PhoQ TCS may be repressed for these phenotypes, and PhoP may be controlled by a mechanism(s) other than PhoQ regulation.     

Chemical decomposition and fixation of nitrite in acidic pasture soils and implications for measurement of nitrification

The fate of added ¹⁵N-labelled nitrite (¹⁵NO₂^?-N) was investigated in a laboratory experiment with two acidic pasture soils collected from northeast Victoria (Maindample and Ruffy) and an alkaline soil collected from Waurn Ponds, Victoria, Australia. Two and a half hours after mixing and extraction, the ¹⁵NO₂^?-N recovered in 2 M KCl extracts was 22% and 33% of the applied NO₂^? in Maindample and Ruffy soils, respectively, and 100% in the Waurn Ponds soil. There was no difference in NO₃^? recovered with and without NaClO₃ addition during this procedure, suggesting that biological oxidation of the applied NO₂^? was not the cause of the low recovery. Of the applied ¹⁵NO₂^?-N, 21% and 20% in the acidic Maindample and Ruffy soils, respectively, were recovered from the organic pool where it is believed to have been chemically fixed, leaving the total loss of ¹⁵NO₂^? as 57% and 47% from these two soils, most likely due to chemical self-decomposition to NO and NO₂. When extracted with 0.005 M KCl, the salt concentration used in the short-term nitrification assay (SNA) 51% and 42% of applied ¹⁵NO₂^? were recovered in the extract from Maindample and Ruffy soils, respectively, but the total losses were only 9% and 10% of the applied ¹⁵NO₂^?-N, respectively. The chemical fixation and self-decomposition of NO₂^? in acidic soils are likely to cause an underestimate of nitrification rates by SNA.     

Evolution of river course and morphometric features of the River Ganga: A case study of up and downstream of Farakka Barrage

River channel shifting in the deltaic regime is an unabated occurrence. Channel shifting has become one of the concerns as it influences land use/land cover along the riverbank in various ways. For the management of the river, it is indispensable to study the pattern of river course change both in qualitative and quantitative methods. This study is an attempt to understand the pattern of shifting and to quantify erosion and deposition of the river Ganga at upstream and downstream of Farakka Barrage during 1794–2017. The study has been carried out by using various historical maps, aerial photographs, satellite imagery, and remote sensing and GIS technique to understand the dynamic of the river. Over 223 years period shifting of the river accentuates the remarkable oscillation of the river. Perimeter of the river is determined to understand the area covered by the river course in the study area. To evaluate the meandering of the river sinuosity of the river has been computed in this study. The amount of erosion and deposition was calculated in this study by using ArcGIS 10.6. The study found a higher amount of erosion at the east bank where Manikchak, Kaliachak II and Kaliachak III blocks are situated between 1965 and 2017. At the west bank of the river, especially the Rajmahal block, the occurrence of deposition was remarkable during the same period.     

Development and evaluation of in vitro somaclonal variation in strawberry for improved horticultural traits

Strawberry cultivation is not popular in Bangladesh due to the unpredictable climatic conditions and lack of proper cultivars. Using somaclonal variation, several new promising selections were generated and evaluated for their flowering and fruiting ability, adaptability and sustainability. To induce variation, plants were regenerated using various tissue culture techniques. Our results suggested that a high concentration of BAP in culture medium successfully resulted in the induction of somaclonal variation. Among the tissue culture techniques adopted in this study, meristem culture was most effective for induction of somaclonal variation. Twenty five putative somaclones with better horticultural features were subsequently selected and field evaluated for three clonal generations. Several of the selections reverted back to their original phenotype within 2–3 vegetative propagations. Three of the stable selections were distinct from each other in terms of fruit and other horticultural characters, and have potential for commercial cultivation in Bangladesh.     

Enzymatic characterization of a cubilin-related serine proteinase from the hard tick Haemaphysalis longicornis

In the present study, we performed enzymatic characterization of Haemaphysalis longicornis serine proteinase (HlSP) with a view to shed light on the mechanisms of blood digestion in the hard ticks. Escherichia coli-expressed recombinant HlSP (rHlSP) was shown to potently hydrolyze the synthetic substrates Bz-(DL)-Arg-pNA, Z-Ala-Ala-Leu-pNA and Suc-Ala-Ala-Ala-pNA and yielded an activity of 31.5, 88.2 and 18.3 mumol/min/mg protein, respectively at an optimum temperature of 25 degrees C. However, the enzyme showed little activity to hydrolyze the substrates Suc-Arg-Pro-Phe-His-Leu-Leu-Val-Tyr-MCA and Pyr-Phe-Leu-pNA. The optimum pH for the enzyme was shown to be 4.0 to 5.0. Several inhibitors such as antipain, leupeptin and phenylmethylsulfonyl fluoride (PMSF), specific for serine proteinase were shown to inhibit enzyme activity by 20-82%, while E-64 (specific for cysteine proteinases) and pepstatinA (specific for aspartic proteinases) had shown only little inhibitory effects on it. This is the first report on enzymatic characterization of a functional serine proteinase from the hard ticks.     

Dietary Protein Requirements of Juvenile Black Sea Bass,Centropristis striata

A feeding trial was conducted in a recirculating system to determine the dietary protein requirement for juvenile black sea bass. Six isocaloric diets were formulated to contain varying levels of crude protein (CP) ranging from 36 to 56% (36, 40, 44, 48, 52, and 56%) by substituting a mixture of carbohydrates and lipid for fish meal. The feeding experiment was carried out in 18‐75 L aquaria stocked at a density of 15 juveniles (initial average weight 6.7 g) per tank. Fish were fed test diets in triplicate tanks to apparent satiation twice a day for 8 wk. Whole‐body proximate composition was analyzed after the feeding trial. After the feeding trial, weight gain and specific growth rate of fish fed the 44% CP diet were not significantly different from those fed the 48, 52, and 56% CP diets, but were significantly higher (P < 0.05) than those fed the 36 and 40% CP diets. Feed conversion efficiency and protein efficiency ratio were significantly affected by dietary protein level. The dietary requirement of protein for maximum growth of black sea bass juveniles, estimated using broken‐line regression analysis on weight gain, was 45.3% and maximum weight gain occurred at 52.6% based on polynomial regression analysis.