In vivo administration of ligands for chicken toll-like receptors 4 and 21 induces the expression of immune system genes in the spleen

Toll-like receptors (TLRs) are a group of conserved proteins that play an important role in pathogen recognition in addition to the initiation and regulation of innate and adaptive immune responses. To date, several TLRs have been identified in chickens, each recognizing different ligands. TLR stimulation in chickens has been shown to play a role in host-responses to pathogens. However, the mechanisms through which TLRs modulate the chicken immune system have not been well examined. The present study was conducted to characterize the kinetics of responses to TLR4 and TLR21 stimulation in chickens following intramuscular injections of their corresponding ligands, lipopolysaccharide (LPS) and CpG oligodeoxynucleotides (ODNs), respectively. To this end, relative expression of cytokine genes in the spleen was determined at 2, 6, 12 and 24 h after injection of TLR ligands. The results indicated that LPS strongly induced the up-regulation of some immune system genes early on in the response to treatment, including interferon (IFN)-γ, interleukin (IL)-10, and IL-1β. Furthermore, treatment with CpG ODN promoted the up-regulation of major histocompatibility complex (MHC)-II, IFN-γ and IL-10. The response to CpG ODN appeared to be somewhat delayed compared to the response to LPS. Moreover, we found a significant increase in IFN-α gene expression in response to LPS but not CpG ODNs. Future studies may be aimed to further characterize the molecular mechanisms of TLR activation in chickens or to exploit TLR agonists as vaccine adjuvants.     

Comparative study on baobab fruit morphological variation between western and south-eastern Africa: opportunities for domestication

The baobab tree (Adansonia digitata L.) is one of the key species for domestication in the semi-arid regions of Africa. In order to help select superior materials for cultivation, fruit morphological variation focussing on pulp content was studied in two physically isolated genetically different baobab populations: Mali and Malawi (West and south-eastern Africa, respectively). In each country eight study sites were selected following a climatic gradient, and their fruit characteristics were measured. Fruit morphology was correlated with climatic and soil data. Significant differences in fruit characteristics between countries and study sites within one country were observed. In general, fruits from Mali tended to be more elongated and their seeds were lighter than those from Malawi. Some sites had significantly high fruit weight and pulp percentage. The general trend (in both countries) was the hotter the environment the lower the pulp percentage, the more spherical the fruits and the smaller the seeds. Moreover, the wetter the environment, the higher the pulp percentage. Results from this study suggest that both genetics and the environment play roles in baobab fruit morphology. Although further research is needed to confirm whether baobabs producing desirable fruits keep producing the same fruits when grown in another environment, it seems that there is room for selecting high quality planting materials.     

Intracellular calcium chelating agent (BAPTA‐AM) aids stallion semen cooling and freezing–thawing

This study aimed to investigate the effects of different concentrations of 1,2‐bis‐(o‐aminophenoxy)‐ethane‐N,N,N0 N0‐tetraacetic acid, tetra‐acetoxymethyl ester (BAPTA‐AM), an intracellular calcium chelating agent, on stallion semen cooling and freezing–thawing. After collection, semen was extended (1:1 v/v) on a skim milk‐based extender, centrifuged and resuspended at 400 million/ml into cooling or freezing extenders containing 0, 5, 25, 50, 100 and 200 μΜ BAPTA‐AM. Motility parameters were assessed after cooling in Equitainer at 5°C for 12, 24, 48, 72 and 120 hr and after freezing–thawing. In addition, mitochondrial membrane potential, intracellular ATP, reactive oxygen species and malondialdehyde concentrations were measured in cryopreserved‐thawed semen. Cooled stored (48 hr) semen containing 50 μΜ BAPTA‐AM and control extender (0 μΜ BAPTA‐AM) was used to assess fertility. Inclusion of 50 μΜ BAPTA‐AM resulted in superior sperm motility parameters during cooled storage when compared to other groups (p < 0.05). Furthermore, semen cryopreserved in extender containing 50 μΜ BAPTA‐AM showed increased intracellular ATP and mitochondrial membrane potential, whereas reactive oxygen species and malondialdehyde were increased after thawing for all groups (p < 0.05). Addition of 50 μΜ BAPTA‐AM to cooling extender resulted in similar pregnancy rates to the control group (75% vs. 73.6%, respectively; p > 0.05). In conclusion, the addition of BAPTA‐AM to semen extenders aided stallion semen cryopreservation in a dose‐dependent manner. Furthermore, the cooling extender supplemented with 50 μΜ BAPTA‐AM could be used to prolong the sperm motility during cooling without apparently compromising fertility. Field trials should be conducted to assess fertility of cryopreserved stallion semen with BAPTA‐AM.     

Genetic algorithms for the sequential irrigation scheduling problem

A sequential irrigation scheduling problem is the problem of preparing a schedule to sequentially service a set of water users. This problem has an analogy with the classical single machine earliness/tardiness scheduling problem in operations research. In previously published work, integer program and heuristics were used to solve sequential irrigation scheduling problems; however, such scheduling problems belong to a class of combinatorial optimization problems known to be computationally demanding (NP-hard). This is widely reported in operations research. Hence, integer program can only be used to solve relatively small problems usually in a research environment where considerable computational resources and time can be allocated to solve a single schedule. For practical applications, metaheuristics such as genetic algorithms (GA), simulated annealing, or tabu search methods need to be used. These need to be formulated carefully and tested thoroughly. The current research is to explore the potential of GA to solve the sequential irrigation scheduling problems. Four GA models are presented that model four different sequential irrigation scenarios. The GA models are tested extensively for a range of problem sizes, and the solution quality is compared against solutions from integer programs and heuristics. The GA is applied to the practical engineering problem of scheduling water scheduling to 94 water users.     

Variation of pomelo (Citrus grandis (L.) Osbeck) in Nepal and participatory selection of strains for further improvement

A farmers’ participatory survey was carried out in the mid-hill and plain (Terai) regions of Nepal to assess the diversity, consumers’ preference for fruit quality and potential for selection of elite pomelo clones. A wide variation of morphological characters of tree, fruit, leaf and seed was identified from information gathered and from laboratory analysis. Multivariate analysis of the data produced five discrete groups, which were represented by plants from different agro-ecological regions and soil types. The groups differed significantly in yield efficiency, fruit shape and size, pulp, juice, total soluble solids and acid content, seed number, leaf shape and size. Some fruit characters, such as yield, size and acid content were found to be affected by environment and genotype, whereas others, such as fruit shape, pulp colour, seed number, bitterness were not affected by environment. Leaf shape and petiole wing shape were also not affected by the environment. Farmers were more interested in quality characteristics rather than to aspects of yield. Six superior types were identified.     

Mutagenic induction of double-podding trait in different genotypes of chickpea and their characterization by STMS marker

A gene that confers double-podding in chickpea is considered to be important for breeding higher yielding cultivars. Double-podded mutants were produced from five desi- and four kabuli-type chickpea genotypes through induced mutations and stabilty was checked up to M₁₃ generation. Desi-type produced higher number of mutants as compared with kabuli-type. The inheritance studies in induced mutants of six genotypes showed that the double-podded trait was governed by single recessive gene. Different genotypes and their double-podded mutants were also characterized through sequence-tagged microsatellite site marker, TA-80. Allelic variations were found in single-podded genotypes and eight different alleles were identified, while for double-poddedness no allelic variants were found in all the analysed mutants. Addition of bases in the double-podded mutants showed that there might be involvement of transposable elements in the production of double-podded mutants through mutagens.     

Immune responses against Marek's disease virus

It is more than a century since Marek's disease (MD) was first reported in chickens and since then there have been concerted efforts to better understand this disease, its causative agent and various approaches for control of this disease. Recently, there have been several outbreaks of the disease in various regions, due to the evolving nature of MD virus (MDV), which necessitates the implementation of improved prophylactic approaches. It is therefore essential to better understand the interactions between chickens and the virus. The chicken immune system is directly involved in controlling the entry and the spread of the virus. It employs two distinct but interrelated mechanisms to tackle viral invasion. Innate defense mechanisms comprise secretion of soluble factors as well as cells such as macrophages and natural killer cells as the first line of defense. These innate responses provide the adaptive arm of the immune system including antibody- and cell-mediated immune responses to be tailored more specifically against MDV. In addition to the immune system, genetic and epigenetic mechanisms contribute to the outcome of MDV infection in chickens. This review discusses our current understanding of immune responses elicited against MDV and genetic factors that contribute to the nature of the response.     

Picobirnavirus detection in bovine and buffalo calves from foothills of Himalaya and Central India

The present study describes detection of picobirnavirus (PBV) in faecal samples from bovine and buffalo calves employing the polyacrylamide gel electrophoresis (PAGE). A total of 136 faecal samples from buffalo (n = 122) and cow calves (n = 14) exhibiting clinical signs of diarrhoea and from healthy calves were collected during 2007–2010 from subtropical (central India) and tarai area of western temperate Himalayan foothills (Uttarakhand). The dsRNA nature of the virus was confirmed by nuclease treatment (RNase A, RNaseT1 and DNase 1). PAGE results confirmed 3.67% (5/136) positivity for PBV, showing a typical genomic migration pattern with two discrete bands with size of approximately 2.4 and 1.7 kbps for the larger and smaller segments, respectively. Among the five PBV samples identified, three were from buffalo calves and one from cow calf exhibiting clinical signs of acute diarrhoea, while one sample from non-diarrhoeic buffalo calf also showed the presence of PBV. None of the samples showed dual infection of rotavirus and PBV. The preliminary findings indicate sporadic incidences of PBV in bovine calves and emphasize the need for the development of better diagnostics for early detection and genetic characterization of these emerging isolates of farm animals of economic significance.     

In vitro micro propagation of “sand pear” Pyrus pyrifolia (Burm. f.) Nakai

This study was undertaken to standardize protocols for in vitro explant establishment, shoot multiplication and in vitro rooting for Pyrus pyrifolia, growing in the Kashmir valley. The explant used was nodal cuttings of 2–3cm size with one or two axillary buds. The highest explant establishment (over 90%) was observed during spring while the lowest (60%) explant establishment frequency was observed during winter season. The shoots sprouted from the axillary buds were excised and subcultured on MS basal medium. The highest shoot multiplication rate (130 shoots from a single nodal cutting) was obtained on MS medium supplemented with BAP 2.2 mg·L^?1 and kinetin 1 mg·L^?1 after four weeks. The shoots were inoculated for rooting in root induction medium of half strength MS salts supplemented with plant growth regulators like IBA, IAA, NAA, and 2, 4-D. However, the best rooting response (8.50 roots per shoot) was obtained in combination of hormones (IBA + NAA) 0.25 mg·L^?1 each. The rooted micro shoots were acclimatized under decreasing humidity regime (95% RH to 75% RH over a period of 5±1 weeks). The highest ex vitro plantlet survival percentage (56.50%) of Pyrus pyrifolia was observed on sand + soil (1:1 v/v).