Protection of mice against <Emphasis Type="Italic">Brucella abortus 544</Emphasis> challenge by vaccination with recombinant OMP28 adjuvanted with CpG oligonucleotides

Brucella abortus, a gram negative, facultative intracellular pathogen causes brucellosis in many animal species and humans. Although live, attenuated vaccines are available against this infection, they suffer from certain limitations. Therefore, the development of an effective subunit vaccine against brucellosis is an area of intense research. The outer membrane proteins (OMPs) of Brucella species have been extensively studied for its immunogenicity and protective ability. We have investigated the potential of CpG ODN to enhance the immunogenicity and protective efficacy of recombinant 28 kDa outer membrane protein (rOMP28) of Brucella melitensis. The study demonstrated vigorous immunoglobulin G (IgG) response of OMP28. The administration of rOMP28 with CpG caused increased cell mediated immune response in terms of induced IgG2a, T-cell proliferation and up-regulation of type I cytokine expression. In contrast, the free antigen suppressed the interferon gamma (type I cytokine) production on in-vitro stimulation of spleenocytes. The result indicates the role of OMP28 in the down regulation of IFN-γ production. Moreover, the B. abortus S-19 vaccinated mice showed highest production of IL-4 and IFN-γ. The protective ability of the antigen was evaluated by systemic bacterial clearance after challenging the mouse with B. abortus 544 pathogen. The level of protection was significant in rOMP28+CpG treated mice but was lower than the required level. The results of the present study indicate that rOMP28 could be an immunogen capable of inducing both humoral and cellular immune response. The humoral response was biased towards Th1 type when it was co-administered with CpG.     

Cryopreservation of silver barb Puntius gonionotus (Bleeker) spermatozoa: effect of extender composition,cryoprotective agents and freezing rate on their postthawing fertilization ability

The effects of extender composition, cryoprotectant concentration and freezing and thawing on the fertilization efficiency of cryopreserved spermatozoa of Puntius gonionotus were evaluated. Computer‐aided motility analysis of semen was conducted to check the suitability of spermatozoa for cryopreservation after mixing with different extenders and cryoprotective agents (CPAs). Extender‐4 with an osmolality 260 mOsmol kg⁻¹and pH 7.6 was used for the cryopreservation study. Among the CPAs, dimethyl sulphoxide (DMSO) was least toxic and more than 60% fertilization was achieved when used at 1.4 M at 0 °C for 10 and 30 min, whereas the toxicity of all CPAs to spermatozoa was evident when tested at 30 °C. Semen frozen at −16 °C min⁻¹ with 1.4 M DMSO showed 70% fertilization, which was significantly higher (P<0.05) than other freezing rates. Samples thawed at 35 °C water showed a fertilization rate comparable with that of fresh semen. Computer‐assisted semen analysis of fresh and frozen semen after thawing showed variations in different types of motility in spermatozoa and in their class. There was no significant difference in motility before or after cryopreservation; however, significant differences could be observed in the average path velocity (VAP), straight line velocity (VSL) and curve linear velocity (VCL). Semen of silver barb could be cryopreserved with extender‐4 by addition of 1.4 M DMSO to a final cryopreservation medium (MED 2) cooled at a rate of −16 °C min⁻¹, stored in liquid nitrogen (−196 °C) and utilized after thawing at 35±2 °C.     

Feed consumption, nutrient utilization and serum metabolite profile of captive blackbucks (Antelope cervicapra) fed diets varying in crude protein content

A feeding trial was conducted to determine the optimum level of crude protein (CP) in the diet of captive blackbuck (Antelope cervicapra) in which feed consumption and nutrient utilization are maximal. Fifteen blackbucks (BW 25-34 kg) were distributed into three groups of five each in an experiment of 75-days duration including a digestion trial of 5-day collection period. All the animals were offered 200 g of concentrates and fresh maize fodder ad libitum. The overall CP content of the three respective diets was 6.9%, 10.4% and 12.7%. Blood samples were collected on the last day of the experiment. Intake and digestibility of CP increased (p < 0.01) with the increased level of CP in the diet. Feed consumption and nutrient intake were not significantly different among the groups. However, digestibilities of most of the nutrients were higher in the 10.4% CP diet than in the 6.9% CP diet. The endogenous loss of nitrogen was similar among the groups. Based on the endogenous losses, minimum N requirement was calculated to be 776 mg/kg BW(0.75) /day, and to meet this requirement, diet must contain at least 8.27% CP. Serum urea nitrogen concentration increased (p < 0.01) with increased level of dietary CP. Serum level of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase was higher (p < 0.05) in the group fed 6.9% CP diet. Animals in the group fed low protein diet also lost body mass during the experimental period. It was concluded that a diet containing 10.4% CP was optimum for maximizing nutrient utilization without any adverse effect on voluntary feed consumption and serum metabolite profile of blackbucks.     

Status of floor vegetation under some monoculture and mixculture plantations in North India

A study conducted to assess the floor vegetation shows the presence of 17 species underPopulus deltoides in comparison to 28, 29 and 35 underAlbizia lebbeck, Dalbergia sissoo and mix-culture plantations, respectively. Further, the biomass and density of floor vegetation is considerably reduced underP. deltoides compared to other plantations. In addition, the indices for species richness, evenness, dominance and diversity are also reduced underP. deltoides showing some inhibitory mechanism being operative under these plantations. Based on available literature, allelopathy is speculated to be responsible for this reduction.     

Low Temperature Effects during Seed Filling on Chickpea Genotypes (Cicer arietinum L.): Probing Mechanisms affecting Seed Reserves and Yield

Chickpea is sensitive to cold conditions (<15 °C), particularly at its reproductive phase and consequently it experiences significant decrease in the seed yield. The information about the effects of cold stress on chickpea during the seed filling phase is lacking. Moreover, the underlying metabolic reasons associated with the low temperature injury are largely unknown in the crop. Hence, the present study was undertaken with the objectives: (i) to find out the possible mechanisms leading to low temperature damage during the seed filling and (ii) to investigate the relative response of the microcarpa (Desi) and the macrocarpa (Kabuli) chickpea types along with elucidation of the possible mechanisms governing the differential cold sensitivity at this stage. At the time of initiation of the seed filling (pod size ∼1 cm), a set of plants growing under warm conditions of the glasshouse (temperature: 17/28 ± 2 °C as average night and day temperature) was subjected to cold conditions of the field (2.3/11.7 ± 2 °C as average night and day temperature), while another set was maintained under warm conditions (control). The chilling conditions resulted in the increase in electrolyte leakage, the loss of chlorophyll, the decrease in sucrose content and the reduction in water status in leaves, which occurred to a greater extent in the macrocarpa type than in the microcarpa type. The total plant weight decreased to the same level in both the chickpea types, whereas the rate and duration of the seed filling, seed size, seed weight, pods per plant and harvest index decreased greatly in the macrocarpa type. The stressed seeds of both the chickpea types experienced marked reduction in the accumulation of starch, proteins, fats, crude fibre, protein fractions (albumins, globulins, prolamins and glutelins) with a larger decrease in the macrocarpa type. The accumulation of sucrose and the activity levels of the enzymes like starch synthase, sucrose synthase and invertase decreased significantly in the seeds because of the chilling, indicating impairment in sucrose import. Minerals such as calcium, phosphorous and iron as well as several amino acids (phenylalanine, tyrosine, threonine, tryptophan, valine and histidine) were lowered significantly in the stressed seeds. These components were limited to a higher extent in the macrocarpa type indicating higher cold sensitivity of this type.     

Exogenous Application of Abscisic Acid Improves Cold Tolerance in Chickpea (Cicer arietinum L.)

Chickpea suffers cold stress (<10 °C) damage especially during reproductive phase resulting in the abortion of flowers and pods, poor pod set, and reduction in seed yield and seed quality. One of the ways in modifying cold tolerance involves exogenous treatment of the plants with chemicals having established role in cold tolerance. In the present study, the chickpea plants growing under optimum temperature conditions (28/12 °C, as average maximum and minimum temperature) were subjected to cold conditions of the field (10–12/2–4 °C; day/night as average maximum and minimum temperature) at the bud stage. Prior to exposure, these plants were treated exogenously with 10 μm abscisic acid (ABA) and thereafter again after 1 week of exposure. The stress injury measured in terms of increase in electrolyte leakage, decrease in 2,3,5-triphenyl tetrazolium chloride reduction %, relative leaf water content and chlorophyll content was observed to be significantly mitigated in ABA-applied plants. A greater pollen viability, pollen germination, flower retention and pod set were noticed in ABA-treated plants compared with stressed plants. The seed yield showed considerable improvement in the plants treated with ABA relative to the stressed plants that was attributed to the increase in seed weight, greater number of single seeded pods and reduction in number of infertile pods. The oxidative damage measured as thiobarbituric acid-reactive substances was lesser in ABA-treated plants that was associated with greater activities of superoxide dismutase, catalase, ascorbate peroxidase, ascorbic acid, glutathione and proline in these plants. It was concluded that cold stress effects were partly overcome by ABA treatment because of the improvement in water status of the leaves as well as the reduction in oxidative damage.     

Pathotyping and antimicrobial susceptibility testing of Escherichia coli isolates from neonatal calves

Neonatal calf mortality is a major concern to livestock sector worldwide. Neonatal calf diarrhoea (NCD), an acute severe condition causes morbidity and mortality in calves. Amongst various pathogens involved in NCD, E. coli is considered as one of the major causes. The study was targeted to characterize E. coli isolates from neonatal calves for diarrhoeagenic Escherichia coli (DEC) types (pathotyping), antimicrobial resistance (AMR) profiling and to correlate with epidemiological parameters. From neonates, a total of 113 faecal samples were collected, out of that 308, lactose fermenting colonies were confirmed as E. coli. Pathotypable isolates (12.3%) were represented by STEC (6.1%), EPEC (2.9%), ETEC (1.9%), EAEC (0.9%) and EHEC (0.3%). Occurrence of STEC was more in non-diarrhoeic calves, whereas ETEC was observed more in diarrhoeic calves. EPEC occurrence was observed in both diarrhoeic and non-diarrhoeic calves. Fishers extract test showed no significant association for occurrence of DEC types to type of dairies, health status, species, breed, age and sex of neonatal calves. Two hundred and eighty isolates were tested for antimicrobial susceptibility. The isolates showed maximum resistance towards ampicillin (55.4%) followed by tetracycline (54.3%), while minimum resistance was observed towards meropenem (2.5%). Multidrug resistant E. coli isolates were found to be 139 (49.6%), and Extended-spectrum beta-lactamase (ESBL) producers were 120 (42.9%). DEC pathotypes like STEC, ETEC, EHEC and EAEC that are also multidrug resistant present in neonatal calves have zoonotic potential and hence are of public health significance.

     

Litter production and decomposition dynamics in moist deciduous forests of the Western Ghats in Peninsular India

A field study was conducted in the moist deciduous forests of the Western Ghats (India) to test the following three hypotheses: (1) Litter production in tropical forests is a function of the floristic composition, density, basal area and disturbance intensity; (2) Decay rate constants of tropical species is an inverse function of the initial lignin/nitrogen ratio; (3) Decomposition rates in tropical forests are faster than temperate forests.

Litter fall was estimated by installing 63 litter traps in the moist deciduous forests of Thrissur Forest Division in the Western Ghats at three sites. Litter fall followed a monomodal distribution pattern with a distinct peak during the dry period from November–December to March–April.Dillenia pentagyna, Grewia tiliaefolia, Macrosolen spp.,Xylia xylocarpa, Terminalia spp.,Lagerstroemia lanceolata, Cleistanthus collinus, Bridelia retusa, andHelicteres isora were the principal litter producing species at these sites. The annual litter fall ranged from 12.18 to 14.43 t ha⁻¹. Structural attributes of vegetation such as floristic composition, basal area, density and disturbance intensity did not directly influence litter fall rates.

Leaf litter decay rates for six dominant tree species were assessed following the standard litter bag technique. One hundred and eight litter bags per species containing 20 g samples were installed in the forest floor litter layer at the same three sites selected for the litter fall quantification exercise. The residual litter mass decreased linearly with time for all species. In general, less disturbed sites and species adapted to higher nitrogen availabilities exhibited relatively higher decay rate coefficients (k). The rapid organic matter turnover observed in comparison with published temperate forest litter decay rates confirms that tropical moist deciduous forest species are characterised by faster decomposition rates.

Mean concentrations of N, P and K in the litter were profoundly variable amongst the dominant species. Initial nitrogen content of the leaf litter varied from 0.65 to 1.6%, phosphorus from 0.034 to 0.077% and potassium from 0.25 to 0.62%.C. collinus, an understorey shrub consistently recorded the lowest litter concentrations for all nutrients. The overriding pattern is one of higher nutrient levels in the overstorey leaf litter and lower concentrations in the understorey litter. Furthermore, as decomposition proceeded, the nitrogen concentration of the residual biomass increased.     

Establishment and growth of coniferous seedlings in an altered forest floor after long-term exclusion of deer

We evaluated differences between the forest floors and the establishment and growth of coniferous seedlings in fenced (13 years) and unfenced plots on Mt Ohdaigahara where the sika deer (Cervus nippon) population density is high. Large coniferous seedlings (height > 0.05 m) were less abundant in the unfenced plot, as a result of deer browsing. Small coniferous seedlings (height < 0.05 m), however, were more abundant in the unfenced plot, where most seedlings of Abies homolepis were found on bare ground and those of Picea jezoensis var. hondoensis were found on buttresses and fallen logs. The large area of bare ground in the unfenced plot was caused by deer browsing. Deer therefore have an indirect effect on the emergence and growth of small coniferous seedlings by modifying the forest floor.     

New gingerdione from the rhizomes of Zingiber officinale

A new gingerdione has been isolated from the rhizomes of Zingiber officinale and identified as 1-dehydrogingerdione (1).