Characterization of resistance gene analogs from <Emphasis Type="Italic">Gossypium arboreum</Emphasis> and their evolutionary relationships with homologs from tetraploid cottons

Four cotton species (genus Gossypium) produce spinable fiber. The two diploid species of Asiatic origin, Gossypium arboreum and G. herbaceum, have been largely replaced by G. hirsutum. However, these diploid species are potentially a rich source of genes for the improvement of G. hrisutum, particularly in terms of providing resistance against biotic and abiotic stresses. As a first step towards understanding the mechanisms of resistance in cotton, we designed 24 non-degenerate primers based on resistance gene analogs (RGAs) cloned from G. hirsutum for screening a number of cotton species with the A and D genomes. Most of these RGAs are conserved on the A genome (G. arboreum), suggesting a bias towards this genome. The amplified RGAs from G. arboreum were cloned and their nucleotide and amino acid sequences compared with RGA sequences available in public databases. The majority of the RGAs identified were homologous to those isolated from G. hirsutum and G. barbadense, but their diversity was greater than expected at both the nucleotide and amino acid levels. These RGAs provide useful tools for the identification of full-length resistance genes from bacterial artificial chromosome and cDNA libraries.     

Effect of improved cultural practices on crop yield and soil salinity under relatively saline groundwater applications

The salinity in the root zone increases with the application of relatively saline groundwater. Therefore, a limited water supply coupled with high pumping cost and salinity hazards, makes it more important than ever that irrigation water be used efficiently and judiciously. In the present study, farmer's practices of irrigation application methods (Field 1) were compared with the water saving techniques (Field 2) for crop yield and salinization for two years with maize–wheat–dhanicha cropping pattern. For maize crop, regular furrow method of irrigation was used in Field 1 and alternate furrow method of irrigation was used in Field 2. For wheat experiments, basin irrigation method of water application was compared with bed and furrow method. For dhanicha, basin irrigation was applied in both the fields. The results showed that about 36% water was saved by applying irrigation water in alternate furrows in each season without compromising the maize crop yield. The salt accumulation in root zone in alternate furrow field was less than that in regular furrow field. The salinity level near the surface increased substantially in both the fields. The water saving in wheat crop under bed and furrow was 9–12% in both seasons. The salinization process in both fields during wheat crop was almost same except redistribution of salts throughout the root zone in basin field of wheat. The salinity developed in root zone during two major growing seasons was leached in monsoon.     

Assessing the critical factors affecting the viability of small-scale dairy farms in the Punjab region of Pakistan to inform agricultural extension programmes

Agriculture in the Punjab province of eastern Pakistan benefits from one of the largest canal irrigation systems in the world. The typical mixed holding is a small, 5 ha mixed farm with three-quarters of its land used for cash crops, such as rice, wheat and sugarcane, and the remainder growing forages such as lucerne and berseem for dairy animals. Both cows and buffaloes are used for milk production, with the latter the more productive. Despite irrigation, productivity is constrained by a slow uptake of new technology such as fertilisers and new plant varieties, and poor livestock management, which leads to extended calving intervals, and a lack of available capital. This study used LP models, constructed with original local data on milk and crop production activities, to investigate the effect on profitability of alleviating the main constraints. The results demonstrate the powerful effect of using better, well managed dairy livestock, of increasing the uptake of simple technological improvements and of widening access to credit. They also show the synergy between these elements, for example the importance of finance as part of any intervention strategy. The results should enable agricultural development policy makers to rank the changes and devise better targeted programmes to deliver the changes on farm.     

Prospects for wheat production under changing climate in mountain areas of Pakistan – An econometric analysis

We assess potential future impacts of climate change on wheat yields in Swat and Chitral districts of Pakistan, mountainous areas with average altitudes of 960 and 1500 m above sea level, respectively. Using past climate data (1976–2000) to track temperature trends in both study districts, we find that increased temperatures correspond to an increase in Growing Degree Days (GDDs) and a decrease in Growing Season Length (GSL). Chitral district shows a stronger decline in season length than Swat district. Compared with the estimated optimum level of 157 days, the 25 year average GSL for the dominant varieties is estimated to be 156 days in Swat district and 195 days in Chitral district. Future increases in temperature of 1.5 and 3 °C are likely to cause wheat yields to decline (by 7% and 24% respectively) in Swat district and increase (by 14% and 23% respectively) in Chitral district. Future increases in precipitation of 5–15% during the growing season show a negligible impact on wheat yield.     

Immunoprotective role of LaSota vaccine under immunosuppressive conditions in chicken challenged with velogenic avian avulavirus-1

The first objective of the present study was to evaluate if the antibodies induced by the live LaSota and killed Newcastle disease (sub-genotype VIIi) vaccines protect the chickens against exposure with pathogenic avian avulavirus-1 (AAvV-1) of chicken and/or pigeon origins. The second objective was to study the effect of vaccines on stressed birds (dexamethasone, aflatoxin, and heat stressed) with respect to antibody production and protection against pathogenic AAvV-1 challenge. Sixty-one-day-old Hubbard chickens were divided into six groups (gA–gF) with ten animals each. All the groups received LaSota (10⁵ EID₅₀, 0.1 ml per chick) on days 7 and 27 via eye drop and one intramuscular injection of a killed vaccine (sub-genotype VIIi) (10^7.5 EID₅₀, 1 ml) on day 18, except the control birds received the PBS only. Moreover, group gC-DEX received dexamethasone intramuscularly at a dose rate of 1-mg/kg body weight daily; gD-AFLA had received aflatoxin as oral gavage at a dose rate of 30 ppb daily, and gE-HEAT was kept under heat stressed (38 °C) till challenged. All the groups were challenged with AAvV-1 strain of chicken origin of sub-genotype VIIi, except the group gA-pigeon was challenged with pigeon-origin strain (sub-genotype VIm). The result showed that the gA-pigeon and gB-chicken vaccinate showed 100% and 80% protection. The immunosuppressive birds produced low pre-challenge HI titer, and protection was observed at 40%, 50%, and 70% in gC-DEX, gD-AFLA, and gE-HEAT, respectively. Our findings suggest the stress factors such as aflatoxin in the feed and dexamethasone are immunosuppressive in nature and suppress the immune response and its associated protective role during infection.

     

Virulence-associated genes and antimicrobial resistance among avian pathogenic Escherichia coli from colibacillosis affected broilers in Pakistan

Avian pathogenic Escherichia coli (APEC) causes colibacillosis that leads to high morbidity and mortality among poultry birds. To date, there is a lack of knowledge about virulence-associated genes (VAGs) and multidrug resistance of APEC isolates from Pakistan. In this study, we determined the VAGs and antibiotic resistance profiles of APEC isolates recovered from colibacillosis affected broilers in Faisalabad region of Pakistan. A total of 84 diseased and dead birds from different local broilers farms were collected and examined for the gross lesions of colibacillosis by conducting postmortem examination. Of these, APEC isolates were recovered from 75 (89.2%) birds. Antibiotic susceptibility tests against 11 antimicrobial agents showed the highest resistance against ampicillin (98.6%) followed by tetracycline (97.3%) and ciprofloxacin (72%). The presence of 11 virulence-associated genes (VAGs) was detected by multiplex polymerase chain reaction (PCR). Of the 75 APEC, 32 (42.6%) harbored > 5 VAGs. Most commonly found genes were increased serum survival (iss; 84%), iron transport (iutA; 74.6%), and colicin V (ColV; 60%). Twenty-two isolates (29.3%) were found to possess a combination of VAGs; iss, tsh, iroN, and iutA, in addition to other VAGs. To the best of our knowledge, this is the first report on the detection of virulence-associated genes and multidrug resistance among APEC isolates in Pakistan. In the future, the strains with the predominant set of VAGs can be used for colibacillosis diagnosis and as a potential vaccine candidate.

     

Epidemiology of Q-fever in goats in Hubei province of China

Tropical Animal Health and Production - Coxiella burnetii (C. burnetii) is an intracellular bacterium, which causes zoonotic disease called Q-fever. However, scarce information is known about the...     

Silage quality as influenced by concentration and type of tannins present in the material ensiled: A meta‐analysis

Protein degradation during ensiling is a major problem. Tannins are known to prevent or decelerate protein degradation in the rumen and may be able to do so in silages as well. Therefore, the present evaluation aimed to analyse the influence of tannins on silage quality. This was done by integrating from all suitable experiments found in literature on the topic in a meta‐analysis approach. A total of 122 datasets originating from 28 experiments obtained from 16 published articles and one own unpublished experiment were included in the database. Tannins in the silages originated either from the plants ensiled or from supplementations of tanniferous plants or tannins extracted from such plants. Tannin concentrations ranged from 0 to 57.8 g/kg dry matter, and the ensiling period varied from 30 to 130 days. The analysis was based on the linear mixed model methodology in which the different studies were considered as random effects and tannin‐related properties (either concentration or type of tannins) were treated as fixed effects. Results revealed that greater concentrations of tannins were associated with a decrease of butyrate concentration in the silages (p < 0.05). An increasing tannin concentration was also accompanied with smaller proportions of soluble N, free amino acid N, non‐protein nitrogen and NH₃‐N in total silage N (p < 0.05). The relationships between hydrolysable and condensed tannins and the decline in butyrate and NH₃‐N concentrations in the silages were of different magnitude (p < 0.05). A higher tannin concentration was associated with a decline in in vitro dry matter digestibility. It was concluded that tannins apparently have the ability to limit extensive proteolysis which may occur during ensiling and thus may improve the fermentative quality of silages. A desired side effect seems to be given by the tannins' apparent property to limit the activity of the butyrate‐producing microbes.     

The effects of growth factors on proliferation of spermatogonial stem cells from Guangxi Bama mini‐pig

The objective of this study was to investigate the effects of different growth factors on the proliferation of Bama mini‐pig spermatogonial stem cells (SSCs) in vitro. The growth factors glial cell line‐derived neurotrophic factor (GDNF), leukaemia inhibitory factor (LIF), GDNF family receptor alpha‐1 (GFRα1) and basic fibroblast growth factor (bFGF) were investigated. The SSCs were seeded on SIM mouse embryo‐derived thioguanine‐ and ouabain‐resistant (STO) feeder layers. Cultivation of the cells were subjected to a factorial design of the growth factors GDNF + bFGF, GDNF + bFGF + GFRα1, LIF + bFGF and LIF + bFGF + GFRα1. The SSCs could propagate for 25 passages in the medium adding GDNF + bFGF + GFRα1, 22 passages in the medium adding GDNF + bFGF, 6 passages in the medium adding LIF + bFGF, or LIF + bFGF + GFRα1. qRT‐PCR analysis showed that the highest mRNA expression levels of NANOG, POU5F, DDX4, GFRα1 and UCHL1 were detected in the group adding GDNF + bFGF + GFRα1. The SSCs from the group adding GDNF + bFGF + GFRα1 also showed UCHL1‐, DBA‐ and CDH1‐positive staining. Moreover, Stra8 and Scp3 expression, and haploid peak were detected after induction of the SSCs from the group adding GDNF + bFGF + GFRα1. In conclusion, pig SSCs could be maintained for long term in the presence of GDNF, bFGF, and GFRα1.