Nitrogen in Relation to Photosynthetic Capacity and Accumulation of Osmoprotectant and Nutrients in Brassica Genotypes Grown Under Salt Stress

Different strategies of the application of nutrients are required to overcome the adverse effects of mustard （Brassica juncea L.） in response to NaCl stress. The objective of the present study was to determine if different added levels of nitrogen （N） in growth medium could alleviate the adverse effects of salt stress on photosynthetic capacity and accumulation of osmoprotectants and nutrients. 14 days mustard seedlings of salt-sensitive （cv. Chuutki） and salt-tolerant （cv. Radha） genotypes were fed with： （i） 0 mmol L^-1 NaCl ＋ 0 mg N kg^-1 sand （control）, （ii） 90 mmol L^-1 NaCl ＋ 30 mg N kg^-1 sand, （iii） 90 mmol L^-1 NaCl ＋60 mg N kg^-1 sand, （iv） 90 mmol L^-1 NaCl ＋90 mg N kg^-1 sand and （v） 90 mmol L^-1NaCl＋ 120 mg N kg^-1 sand. Under the condition of salinity stress, N application caused a significant ameliorative effect on both genotypes with respect to growth attributes [fresh weight （FW） and dry weight （DW）] and physio-biochemical parameters [percent water content （WC）, net photosynthetic rate （PN）, stomatal conductance （gs）, total chlorophyll （Ch1）, carbonic anhydrase （CA） activity and malondialdehyde （MDA）, nitrogen （N）, potassium （K） and sodium （Na） contents, and K/Na ratio] and yield attributes （number of pods/plant, seeds/pod and seed yield/plant）. The salt-tolerant genotype exhibited maximum value for growth, physio-biochemical and yield attributes at 60 mg N kg 1 sand than that of salt-sensitive genotype. These results suggest that application of N may ameliorate most of the attributes and prove to be a physiological remedy to increase the tolerance against the ill effects of salt stress in Brassicas.     

Exploring student attitudes to directed self-learning online through evaluation of an Internet-based biomolecular sciences resource

RATIONALE FOR THE STUDY: In 2000, funding was awarded by the University of Glasgow's Learning and Teaching Development Fund (L&TDF) for the authors to develop an interactive, online learning resource for veterinary biomolecular sciences teaching. This course is a core component of the veterinary undergraduate curriculum at the university. Evaluations were carried out to gauge students' experiences of using the resource as a basis for exploring students' attitudes toward online, independent learning. METHODOLOGY: Peers were asked to review the design and content of four modules, also evaluated by students using questionnaires and focus group discussions. Additionally, students were observed using the modules. Both first-year students and second-year direct-entry students (i.e., students entering the veterinary program with advanced training) participated in the evaluation, which allowed for some comparison between the groups. One cohort used the modules independently, and their responses were compared with the cohorts that used the modules in scheduled classes. RESULTS AND CONCLUSIONS: The evaluations indicate that this is a useful resource that could act as a template for other courses within the veterinary undergraduate curriculum, particularly for learning of basic sciences. On average, first-year and timetabled students rated the program more highly overall, rated the program more highly in relation to previous instruction, and rated tutor presence as more important than second-year direct-entry and independent students did. The lower rating given to tutor presence by second-year direct-entry and independent students indicates that they are more confident using the modules without tutor supervision.     

Cowpea mild mottle virus could not be detected by ELISA in soybean and groundnut seeds in Indonesia

Using ELISA to determine whether cowpea mild mottle virus (CMMV) was present in soybean and groundnut seeds, the virus was not detected in 4144 seeds harvested from seven CMMV-infected soybean genotypes and in 214 seeds collected from CMMV-infected groundnut plants (cv. Gajah). These results, together with those of other researchers, suggest that, under the conditions tested, CMMV is not transmitted by seed. This in contrast to what is generally accepted and published in reviews.     

Bovine papillomavirus infection in equine sarcoids and in bovine bladder cancers

Bovine papillomavirus (BPV) type 2 is involved in carcinogenesis of the urinary bladder in cattle, while BPV-1 is commonly associated with equine sarcoid tumours. In both cases the early viral proteins are expressed, but virion is not produced. Given the similarities in BPV biology between the tumours in cattle and horses, bovine bladder cancers and equine sarcoids were compared with respect to physical status, load of viral DNA and variability of the E5 open reading frame (ORF). Rolling circle amplification demonstrated that BPV-1 and BPV-2 genomes exist as double stranded, episomal, circular forms in the two tumours. Realtime quantitative PCR revealed that equine sarcoids contained higher viral DNA loads compared to bovine bladder cancers. The BPV-1 E5 ORF showed sequence variation but BPV-2 ORF did not. The presence of BPV-1 E5 variations or their absence in the BPV-2 E5 ORF does not appear to have an effect on viral DNA load in either tumour type.     

Combined Application of Boron and Zinc Influence the Leaf Mineral Status,Growth, Productivity and Fruit Quality of ‘Kinnow’ Mandarin (Citrus nobilis Lour × Citrus deliciosa Tenora)

The deficiency of mineral nutrients, particularly of boron (B) and zinc (Zn) in many citrus orchards of Pakistan affect yield and quality. Effect of foliar application of B and Zn on leaf mineral nutrients, growth, productivity, and quality of ‘Kinnow’ were studied. Trees were sprayed with 37 mM boric acid and 49 mM zinc sulfate either alone or in combination at fruit setting stage or fruit setting and pre-mature stages. Leaf phosphorus (P), potassium (K), B, and Zn were significantly increased with treatments. Lowest fruit drop and maximum fruit weight and number, highest level of ascorbic acid, and reducing sugars were recorded in the trees sprayed with combine application of B and Zn at fruit set stage. In conclusion, combined application of B and Zn at fruit setting stage can be used effectively to increase nutrient uptake, reduce fruit drop, and increase yield with better quality of ‘Kinnow’ mandarin fruit.     

Pharmacokinetics and bioavailability of tildipirosin following intravenous and subcutaneous administration in sheep

Tildipirosin is a semi‐synthetic macrolide antibiotic commonly used in cattle and swine to treat bacterial pneumonia. The objective of this study was to investigate the pharmacokinetic profile of tildipirosin after a single intravenous (i.v.) and subcutaneous (s.c.) administration in healthy lambs. Eighteen lambs were randomly divided into three groups (n = 6 each). Lambs received a single s.c. dose of tildipirosin at 4 and 6 mg/kg b.w. in group 1 and 2, respectively. Lambs in group 3 received a single i.v. dose of tildipirosin at 4 mg/kg b.w. Blood samples were collected at 0, 0.5, 0.75, 1.5, 2, 3, 4, 6, 8, 10, 24, 36, 48 hr, and every 24 hr to day 21, and thereafter at day 28 posttildipirosin administration. The plasma concentrations of tildipirosin were determined using high‐performance liquid chromatography with tandem mass spectrometry detection (LC?MS?MS). All lambs appeared to tolerate both the intravenous and subcutaneous injection of tildipirosin. Following i.v. administration, the elimination half‐life (T_1/2), mean residence time (MRT), volume of distribution (Vd/F), and total body clearance (Cl/F) were 119.6 ± 9.0 hr, 281.9 ± 25.7 hr, 521.1 ± 107.2 L, and 2.9 ± 0.5 L/hr, respectively. No significant differences in C_max (657.0 ± 142.8 and 754.6 ± 227.1 ng/ml), T_max (1.21 ± 0.38 and 1.35 ± 0.44 hr), T_1/2 (144 ± 17.5, 156.5 ± 33.4 hr), and MRT (262.0 ± 30.2 and 250.6 ± 54.5 hr) were found in tildipirosin after s.c. dosing at 4 and 6 mg/kg b.w., respectively. The absolute bioavailability (F) of tildipirosin was 71.5% and 75.3% after s.c. administration of 4 and 6 mg/kg b.w., respectively. In conclusion, tildipirosin was rapidly absorbed and slowly eliminated after a single s.c. administration in healthy lambs. Tildipirosin could be used for the treatment and prevention of respiratory bacterial infections in sheep. However, further in vitro and in vivo studies to determine the efficacy and safety are warranted. To our knowledge, this is the first study to determine the tildipirosin pharmacokinetic parameters in sheep plasma.     

Effect of weaning method on body weight,testicular growth,sexual behavior,age of puberty,and testosterone concentration of Beetal bucks

The current study evaluates the effects of early (8th week) and late (16th week of age) weaning of male goat kids on their body growth, testicular growth, sexual behavior, plasma testosterone concentration, and pubertal age. Early (n = 6) and late (n = 7) weaned Beetal bucks were weekly monitored from 18th to 38th week for their body weight, scrotal circumference, testicular volume, testicular echogenicity (via ultrasonography), sexual activities, and plasma testosterone concentration. In comparison to early-weaned, late-weaned bucks showed a marked increase (p < .05) in body weight (11.4 ± 0.8 vs. 13.7 ± 0.6kg), testicular volume (44.1 ± 7.2 vs. 79.8 ± 18.7cm³), scrotal circumference (10.7 ± 0.6 vs. 12.8 ± 0.7cm), and testicular echogenicity (28.3 ± 2.7 vs. 38.3 ± 2.1) from 18th, 28th, 21st, and 24th week onward, respectively. Sexual activities started earlier in late- than early-weaned bucks (22nd vs. 25th week, respectively). Moreover, the sexual behavior index was better (p < .05) after the 34th week in late than early-weaned bucks. The plasma concentration of testosterone (at 39 weeks of age) was relatively more and the onset of puberty was 2–3 weeks earlier (p < .05) in late than early-weaned bucks. In conclusion, age-based early weaning of male kids impairs their testicular growth, sexual behavior, and age at puberty compared to conventional weaning.     

Indica rice varietal development in Pakistan: an overview

Pakistan is well known for its basmati rice with long grain and aroma, as well as for non-basmati indica varieties; however average yield is lower as compared with other countries. Besides, cultural practices, the main reason for low productivity in Pakistan is that, local varieties are susceptible to different biotic and abiotic factors like insect pests, diseases, drought, and salinity. Different approaches have been undertaken in Pakistan to tackle these problems through traditional breeding of selection and crossing, mutation breeding, somaclonal variation as well as plant transformation studies in recent past. For variety development, the most successful examples arose from traditional breeding that produced famous basmati varieties like Basmati 370, Basmati 385 and Super basmati, and non-basmati varieties such as IRRI-6, DR-82, DR-83, DR-92, Swat-I and Swat-II, which earn a significant share of foreign exchange every year. Six varieties have also been developed through mutation breeding, and one through exploitation of somaclonal variation but their contribution to the national economy is not significant. On the other hand, no variety has been registered as commercial by plant transformation groups. This review discusses the problems and prospects of rice breeding with special emphasis on basmati rice in Pakistan particularly in Pakistani Punjab (a major producing area), as well as focuses on future research programs.     

Effect of shading on accumulation of soybean isoflavonoid under maize-soybean strip intercropping systems

Maize-soybean strip intercropping system is an important ecological planting system; the wide development of intercropped soybean has contributed to the soybean industry in China. Soybean growth and seed production were affected by the shading from maize. Previous studies confirmed that relay strip intercropping shading facilitates the accumulation of isoflavone glucosides but does not take advantage of the accumulation of isoflavone aglycone. However, the regulation of isoflavones accumulation under strip intercropping system was unknown; in which soybean and maize were sown at the same time, and soybean was mainly shaded in the reproductive stage. In order to reveal the effects of intercropping shading on the isoflavones accumulation in soybean seed, two independent field experiments were conducted in eastern China. We compared the isoflavones profiles of soybean seeds, which were grown under various maize-soybean intercropping systems with different shade levels. The results showed that the intercropping shading was not benefited to the accumulation of soy-isoflavones, including aglycones and isoflavones glycosides and various forms of isoflavones were decreased with the decline of photosynthetic active radiation. Multivariate statistical analysis and significance analysis showed that acylated isoflavones may be more susceptible to intercropping shading.

Abbreviations: HCA: Hierarchical cluster analysis; PAR: photosynthetically active radiation; PCA: Principal component analysis; LC-MS: Liquid chromatography mass spectrometer.     

Resistance in field populations of <Emphasis Type="Italic">Amrasca devastans</Emphasis> (Hemiptera: Cicadellidae) to new insecticides in Southern Punjab,Pakistan

Cotton jassid, Amrasca devastans (Distant), is an economically important pest of various crops (i.e. cotton, okra, brinjal) and has the potential to become resistant against insecticides due to the intense use of insecticides in the region which entails high selection pressure. To monitor the resistance levels against recently used new chemistry insecticides (nitenpyram, spirotetramat, chlorfenapyr, fipronil, emamectin benzoate, sulfoxaflor, and flonicamid), four field populations of A. devastans collected from Khanewal, Multan, Muzaffargarh and Lodhran districts were examined by leaf dip bioassays. The results revealed the 32.95–136.47 fold resistance to nitenpyram, 23.03–56.74 fold to spirotetramat, 10.84–31.33 fold to chlorfenapyr, 1.20–9.43 fold to fipronil, 3.27–43.77 fold to emamectin benzoate, 0.66–2.81 fold to sulfoxaflor and 0.59–1.25 fold to flonicamid in different field populations, compared to the susceptible strain. Based on present study findings, it may be suggested to discontinue the use of nitenpyram, spirotetramat, chlorfenapyr and emamectin benzoate for which the populations were resistant and the rotational use of fipronil, sulfoxaflor and flonicamid for which the populations were susceptible. Proactive resistance management approaches such as judicious use of insecticides with proper dose selection, time of spray on early stages and correct method of application are necessary to prevent the development of resistance.