Brucella abortus RB51: enhancing vaccine efficacy and developing multivalent vaccines

Brucella abortus vaccine strain RB51 is an attenuated, stable rough mutant that is being used in many countries to control bovine brucellosis. Our earlier study demonstrated that the protective efficacy of strain RB51 can be significantly enhanced by overexpressing Cu–Zn superoxide dismutase (SOD), a homologous protective antigen. We have also previously demonstrated that strain RB51 can be engineered to express heterologous proteins and mice vaccinated with such recombinant RB51 strains develop a strong Th1 type of immune response to the foreign proteins. The present study is aimed at combining these two characteristics to generate new recombinant RB51 vaccines with enhanced abilities to protect against brucellosis and simultaneously able to protect against infections by Mycobacterium spp. We constructed two recombinant RB51 strains, RB51SOD/85A which overexpresses SOD with simultaneous expression of the 85A, a protective protein of Mycobacterium spp., and RB51ESAT which expresses ESAT-6, another protective protein of M. bovis, as a fusion protein with the signal sequence and few additional amino terminal amino acids of SOD. Mice vaccinated with these recombinant strains developed specific immune responses to the mycobacterial proteins and significantly enhanced protection against Brucella challenge compared to the mice vaccinated with strain RB51 alone.     

Sustainability at a cost: An inceptive analysis of “extended” fishing ban on the livelihoods of fishers of Tamil Nadu

An emphasis on sustainable marine fish production has paved the way for the enactment of Marine Fisheries Regulation Acts and subsequent regulations in India. A closed season ban on fishing has been one of the very few successful regulatory measures since its introduction in 2001 in Tamil Nadu. Since 2017, the fishing ban period has been extended from 45 to 60 days for the east coast of India, for ecosystem‐based marine fisheries management. This study analyses the socioeconomic impacts of change in the fishing ban (closed season) across the four coastal zones of Tamil Nadu. For the past 10 years, CPUE has been stable or increased marginally. Among the four coasts, the relative change in employment and labour income loss was highest for Palk Bay (36.84%). Transaction costs of implementation of the ban caused an additional expense of Rs 496.5 million to the Government in 2017 and the overall total labour income loss has leaped from Rs 1,638.2 to 2,100.2 million due to the extension of the ban. The fishing ban has aided in the recovery of habitat and regeneration of stock through recruitment. Training and capacity building on alternative livelihood options are highly recommended to enable the workers to cope with the ban period.     

Polyclonal antibody‐based farmer‐friendly flow‐through test for the detection of acute hepatopancreatic necrosis disease in shrimp

Early mortality syndrome (EMS) or acute hepatopancreatic necrosis disease (AHPND) is currently the most significant disease of shrimp in farms of Vietnam, Thailand, Malaysia, China and Mexico, and there is a great risk that it may spread to other shrimp farming countries. Although, an array of sophisticated detection tools for AHPND available, there is a need for a sensitive, simple and rapid detection method. In this study, a simple, sensitive, rapid and polyclonal antibody‐based farmer‐friendly flow‐through assay (FTA) test has been developed for the detection of AHPND pathogen. The recombinant Photorhabdus insect‐related (Pir) A toxin‐like protein of AHPND pathogen was used to immunize rabbits at 21‐day interval observed for highest antibody titre after third booster by ELISA. The raised rabbit antiserum was purified by affinity chromatography and characterized by Western blot. The antiserum showed no cross‐reactivity with AHPND‐free Vibrio parahaemolyticus, V. anguillarum, White Spot Virus (WSV), Aeromonashydrophila and Aphanomycesinvadans. This polyclonal rabbit antiserum was used to develop a farmer‐friendly FTA test for the detection of AHPND pathogen. This simple FTA testis is more sensitive and could detect PirA^VP toxin up to 0.121 µg/ml, compared with 0.242 µg/ml by immunodot assay. Furthermore, FTA test requires only 8–10 min for completion, compared with 3 hr by immunodot thus found to be more sensitive, specific and cost‐effective. Collectively, sensitive FTA test would help shrimp farmers to take real‐time management decisions, especially emergency harvest and finally be a better hope for the prevention of AHPND.     

Impacts of elemental S applied under various temperature and moisture regimes on pH and available P in acidic, neutral and alkaline soils

We evaluated the effect of elemental S (S⁰) under three moisture (40, 60, 120% water-filled pore space; WFPS) and three temperature regimes (12, 24, 36°C) on changes in pH and available P (0.5 N NaHCO₃-extractable P) concentrations in acidic (pH 4.9), neutral (pH 7.1) and alkaline (pH 10.2) soils. Repacked soil cores were incubated for 0, 14, 28 and 42 days. Application of S⁰ did not alter the trends of pH in acidic and neutral soils at all moisture regimes but promoted a decrease in the pH of alkaline soil under aerobic conditions (40%, 60% WFPS). Moisture and temperature had profound effects on the available P concentrations in all three soils, accumulation of available P being greatest under flooded conditions (120% WFPS) at 36°C. Application of S⁰ in acidic, neutral and alkaline soils resulted in the net accumulation of 16.5, 14.5 and 13 g P g^–1 soil after 42 days at 60% WFPS, but had no effect under flooded conditions. The greatest available P accumulations in the respective soils were 19, 19.5 and 20 g P g^–1 soil (equivalent to 38, 41, 45 kg P ha^–1) with the combined effects of 36°C, 60% WFPS and applied S⁰. The results of our study revealed that oxidation of S⁰ lowered the pH of alkaline soil (r=–0.88, P<0.01), which in turn enhanced available P concentrations. Also, considering the significant relationship between the release of sulphate and accumulation of P, even in acidic soil (r=0.92, P<0.01) and neutral soil (r=0.85, P<0.01) where the decrease in pH was smaller, it is possible that the stimulatory effect of sulphate on the availability of P was due to its concurrent desorption from the colloidal surface, release from fixation sites and/or mineralization of organic P. Thus, in the humid tropics and irrigated subtropics where high moisture and temperature regimes are prevalent, the application of S⁰ could be beneficial not only in alleviating S deficiency in soils but also for enhancing the availability of P in arable soils, irrespective of their initial pH.     

Effects of long-term legume cover crop incorporation on soil organic carbon, microbial biomass, nutrient build-up and grain yields of sorghum/sunflower under rain-fed conditions

Low organic matter, poor fertility and erosion are common features of rain‐fed Alfisols in southern India. Build‐up of organic matter is crucial to maintain sustainable production on these soils. The possibility of on‐farm generation of legume biomass [horsegram; Macrotyloma uniflorum (Lam.) Verdc.] by using off‐season rainfall was examined in two field experiments involving sorghum and sunflower from 1994 to 2003. The effects of this incorporation were assessed on crop yields and soil properties for 10 years together with fertilizer application. Horsegram biomass ranging from 3.03–4.28 t ha^?1 year^?1 (fresh weight) was produced and incorporated in situ under different levels of fertilizer application. Annual incorporation improved the soil properties and fertility status of the soil, which resulted in improved yields of test crops. With biomass incorporation, mean organic carbon content improved by 24% over fallow. Microbial biomass carbon improved by 28% at site I. Long‐term biomass incorporation and fertilizer application resulted in the build‐up of soil nutrients compared with the fallow plots. Application of N and P alone resulted in a negative balance of soil K. A time‐scale analysis of yields showed that incorporation together with fertilizer application maintained a stable yield trend over a 10‐year period in sorghum, whereas fertilizer application alone showed a declining trend. At the end of 10 years of incorporation, the increase in grain yield because of incorporation was 28 and 18%, respectively, in sorghum and sunflower over fallow when no fertilizers were applied to rainy season crops. The incorporation effect was even larger in plots receiving fertilizer. The growing and incorporation of a post‐rainy season legume crop is a low‐cost simple practice that even small and marginal farmers can adopt in semi‐arid regions of the country. Widespread adoption of this practice, at least in alternate years, can restore the productivity of degraded soils and improve crop yields.     

Effects of endotoxin-induced fever and probenecid on disposition of enrofloxacin and its metabolite ciprofloxacin after intravascular administration of enrofloxacin in goats

Pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin were investigated in normal, febrile and probenecid‐treated adult goats after single intravenous (i.v.) administration of enrofloxacin (5 mg/kg). Pharmacokinetic evaluation of the plasma concentration–time data of enrofloxacin and ciprofloxacin was performed using two‐ and one‐compartment open models, respectively. Plasma enrofloxacin concentrations were significantly higher in febrile (0.75–7 h) and probenecid‐treated (5–7 h) goats than in normal goats. The sum of enrofloxacin and ciprofloxacin concentrations in plasma ≥0.1 μg/mL was maintained up to 7 and 8 h in normal and febrile or probenecid‐treated goats, respectively. The t1/2β, AUC, MRT and ClB of enrofloxacin in normal animals were determined to be 1.14 h, 6.71 μg.h/mL, 1.5 h and 807 mL/h/kg, respectively. The fraction of enrofloxacin metabolized to ciprofloxacin was 28.8%. The Cmax., t1/2β, AUC and MRT of ciprofloxacin in normal goats were 0.45 μg/mL, 1.79 h, 1.84 μg.h/mL and 3.34 h, respectively. As compared with normal goats, the values of t1/2β (1.83 h), AUC (11.68 μg ? h/mL) and MRT (2.13 h) of enrofloxacin were significantly higher, whereas its ClB (430 mL/h/kg) and metabolite conversion to ciprofloxacin (8.5%) were lower in febrile goats. The Cmax. (0.18 μg/mL) and AUC (0.99 μg.h/mL) of ciprofloxacin were significantly decreased, whereas its t1/2β (2.75 h) and MRT (4.58 h) were prolonged in febrile than in normal goats. Concomitant administration of probenecid (40 mg/kg, i.v.) with enrofloxacin did not significantly alter any of the pharmacokinetic variables of either enrofloxacin or ciprofloxacin in goats.     

Chemical Characterization of Bovine Urine with Special Reference to Oestrus

Cows' urine was analysed by gas chromatography–mass spectrometry (GC-MS). The profiles from preovulatory, ovulatory and postovulatory samples were compared to establish any qualitative and quantitative differences that might have potential value in olfactory communication. Dichloromethane was used as the solvent for extraction of the compounds. Seven different compounds were detected, of which only two were common to all the chromatograms. The chemical profile of oestrous urine was distinguished by the presence of two specific compounds, viz. di-n-propyl phthalate and 1-iodoundecane, that were not found in the other samples. As oestrous urine has been shown to elicit sexual behaviour in cattle, these two characteristic peaks may represent important chemical compounds that elicit signals that allow the bull to detect `oestrous odours'.     

Expression of skin color genes in lymphocytes of Karan Fries cattle and seasonal relationship with tyrosinase and cortisol

To evaluate difference in the expression of skin color genes (melanocortin 1 receptor (MC1R) and premelanosome (PMEL)) in lymphocytes during winter and summer season and their correlation with tyrosinase enzyme and cortisol, ten Karan-Fries heifers were selected from National Dairy Research Institute (NDRI) cattle farm. Blood samples were collected from the animals during winter (THI?=?60) and summer (THI?=?83) season at weekly intervals. Relative MC1R and PMEL messenger RNA (mRNA) expression of Karan Fries cattle was found to be significantly (P?P?P?相似文献   

Macroscopic, neat, single-walled carbon nanotube fibers

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties.