Fruiting behavior of dipterocarps in two consecutive episodes of general flowering in a Malaysian lowland rain forest

We examined fruiting behaviors of 24 dipterocarp species in a lowland rain forest of Peninsular Malaysia during two consecutive episodes of general flowering (GF). The first GF episode (GF2001) occurred from August 2001 to February 2002, and the second GF episode (GF2002) followed immediately, from March to September 2002. The magnitude of GF2002 was greater than that of GF2001 at the community level. Significant positive size dependence of fruiting behavior at the community level was found in both GF2001 and GF2002, but there was no significant association between the fruiting behaviors in GF2001 and GF2002 except for one species. These results imply that tree size was one of the explanatory factors for fruiting behavior of dipterocarp species, but there was no evidence that adjacent reproduction caused the absence of reproduction and decreased fecundity in the subsequent fruiting event. In contrast, strong spatial aggregation of fruiting trees was found in GF2001, suggesting that external factors may affect fruiting behavior of dipterocarps in a minor GF episode. Among the 12 study species, there were large variations in fruiting behavior, but growth type (e.g., fast-growing or slow-growing) did not simply explain the inter-specific pattern of fruiting behavior. Thus, tree size may account for fruiting behavior of dipterocarps during the consecutive GF episodes through species-specific differences in phonological responses to internal and external conditions.     

The low down on association mapping in hexaploid wheat (Triticum aestivum L.)

The past few decades have witnessed hundreds of family-based linkage studies mapping for numerous traits but only a limited number of QTLs were actually cloned, tagged, or used for marker-assisted selection. Although providing valuable information, this conventional approach cannot be scaled up to underpin the incredible amount of phenotypic variation in the form of 266, 589 hexaploid wheat accessions maintained in public germplasm collections. Association mapping has recently emerged as an alternative and more powerful mapping approach where a natural population is surveyed to determine marker-trait associations using linkage disequilibrium (LD). After its first application for milling quality in 2006, association mapping studies in hexaploid wheat are being extended to tag yield traits, protein quality, and tolerance to biotic and abiotic stresses. Advances in genotyping technology and statistical approaches greatly accelerated the shift from conventional linkage-based mapping to LD-based association mapping. Association mapping stands out because of simultaneous utilization of a large number of ex situ-conserved natural variation due to historical recombination events accumulated over centuries.     

Acaricidal activity of aqueous extract and synthesized silver nanoparticles from Manilkara zapota against Rhipicephalus (Boophilus) microplus

Traditional parasite control is primarily based on the use of chemical acaricides, which unfortunately have many negative side effects. The aim of the present study was to evaluate the effect of plant synthesized silver nanoparticles (AgNPs) using aqueous leaf extract of Manilkara zapota to control Rhipicephalus (Boophilus) microplus. The synthesized AgNPs were characterized by UV-vis spectrum, scanning electron microscopy (SEM), Fourier transform infrared and X-ray diffraction. The UV-vis spectrum of the aqueous medium containing silver nanostructures showed a peak at 421 nm corresponding to the surface plasmon resonance band of AgNPs. SEM supports the biosynthesis and characterization of AgNPs with spherical and oval in shape and size of 70-140 nm. Acaricidal activity of aqueous leaf extract of M. zapota and synthesized AgNPs were carried out against R. (B.) microplus and the results showed the LC(50) values of 16.72 and 3.44 mg/L; r(2)=0.856 and 0.783), respectively.     

Causes and consequences of shifting cultivation and its alternative in the hill tracts of eastern Bangladesh

Shifting cultivation, which is still prevalent in the uplands of eastern Bangladesh, contributes significantly to forest loss and is the main cause of land degradation. This paper presents the causes and consequences of shifting cultivation and its potential land use alternatives. The analysis presented is primarily qualitative with a supplementary quantitative analysis of the causes of forest loss by logistic regression. The results of the study show that traditional land practices, exacerbated by poverty and associated with a lack of technical knowledge is the main cause for the continuation of unsustainable shifting cultivation. Population pressure, inadequate land for cultivation, low education levels, policy planning and implementation without local participation are all factors that influence farmers’ decision to continue shifting cultivation. Intensive land management through agroforestry is a promising alternative that can sustainably manage the remaining forest resources. If adopted, such systems potentially provide good economic returns, and may significantly reduce rural poverty.     

Modulation of in vitro morphogenesis in nodal segments of Salix tetrasperma Roxb. through the use of TDZ, different media types and culture regimes

A comparative performance of two different media formulations (woody plant medium (WPM) and Murashige and Skoog??s (MS) medium) for their ability to inflict in vitro shoot development in nodal segments of Salix tetrasperma Roxb. has been carried out. Thidiazuron (TDZ) in various concentrations was used as a supplement to the basal media. Media types, TDZ concentrations, exposure duration and culture regimes played an important role in affecting multiple shoot production. WPM supplemented with 2.5???M TDZ for 4?weeks exposure was found to be the best for maximum (4.53?±?0.27) shoots production in vitro. Transfer to a secondary medium consisting of 6-benzyladenine (1.0???M) and ??-naphthalene acetic acid (0.5???M) enhanced the multiplication rate and by the end of 12?weeks, 20.33?±?0.33 shoots with shoot length, 4.70?±?0.26?cm were produced on WPM. Rooting of the regenerated shoots was achieved on half strength basal media (either WPM or MS) containing 0.5???M indole-3-butyric acid. In all the experiments, different growth parameters were scored and WPM was found to be superior to MS medium. The regenerated plantlets were successfully acclimatized in the field with about 81?% survival.     

Therapy and prevention of cryptosporidiosis in animals

Cryptosporidiosis is a common gastro-intestinal illness in animals and man worldwide. The disease is devastating in immune-suppressed individuals but self-limiting in competent hosts. The infectious stages of the organism (oocysts) are shed in the faeces of affected individuals, survive in adverse environmental conditions and spread by direct contact or through contaminants (food, water). Due to the robustness of the oocysts, their tenacity, tiny size, and resistance to common disinfectants, the parasite is difficult to eradicate from contaminated environments. To obtain sufficient control both treatment of infected hosts and inactivation of oocysts are necessary. Several drugs are commonly used to treat cryptosporidiosis in man and very few in animals but none of them are completely effective in terms of both clinical and parasitological response. Only a few chemical agents are able to inactivate oocysts in the environment including water treatment plants but their application has certain limitations. Therefore, control of cryptosporidiosis remains a global challenge in both veterinary and human medicine. Extensive research has been performed on suitable drugs and disinfectants. Thousands of agents have been tested both in vivo and in vitro. Some are excitingly active in vitro but exhibit poor or no response in clinical trials. Currently, no single or combined drug therapy has proven to be completely effective against this disease. This article will focus on therapy and prevention of cryptosporidiosis in animals including perspectives for new drugs.     

Immunostimulatory and protective effects of Aloe vera against coccidiosis in industrial broiler chickens

This paper reports the immunostimulatory and protective effects of Aloe vera extracts (aqueous and ethanolic) against coccidiosis in industrial broiler chickens. The study was divided into two experiments. Experiment-I was conducted for the evaluation of immunostimulatory activity of A. vera and experiment-II demonstrated the protective efficacy of A. vera extracts against coccidiosis in chickens. Results of the experiment-I revealed significantly higher (p<0.05) lymphoproliferative responses in chickens administered with ethanolic extract of A. vera as compared to those administered with aqueous extract and control group. Microplate haemagglutination assay for humoral response on day 7th and 14th post primary and secondary injections of sheep red blood cells (SRBCs) revealed significantly higher (p<0.05) anti SRBC antibody (total Igs, IgG and IgM) titers in chickens of experimental groups as compared to the control group. None of the extracts, however, demonstrated significant effects on the development of lymphoid organs. Results of experiment-II revealed maximum protection (60%) in chickens administered with aqueous Aloe extract as compared to the ethanolic extract administered chickens (45%). Mean oocysts per gram of droppings in the control group was significantly higher (p<0.05) as compared to the chickens in both the experimental groups. Chickens administered with aqueous Aloe extract showed a minimal mean lesion score (2.3) followed by those administered with ethanolic Aloe extract (2.6) and control chickens (3.05) for caeca, and a similar pattern was observed for intestinal lesion scoring. Further, significantly higher weight gains and antibody titers (p<0.05) were observed in chickens administered with A. vera extracts as compared to those in the control group. It was concluded that A. vera may be a potential and valuable candidate to stimulate the immune responses and can be used successfully as an immunotherapeutic agent against coccidiosis in industrial broiler chickens.     

Oral administration of Salmonella enterica serovar Typhimurium expressing swine interleukin-18 induces Th1-biased protective immunity against inactivated vaccine of pseudorabies virus

Enhancing and/or modulating innate and adaptive immunity by cytokines appears to be greatly useful to provide effective protective immunity against infectious diseases. However, an effective delivery system for mass administration in livestock industry is needed because of limitations such as cost, labor, time, and protein stability. Here the immunomodulatory functions of swine interleukine-18 (swIL-18), known as IFN-γ-inducing factor (IGIF), were evaluated in a vaccination model of pseudorabies virus (PrV) using attenuated Salmonella enterica serovar Typhimurium as the oral delivery system. The oral administration of S. enterica serovar Typhimurium expressing swIL-18 prior to vaccination with inactivated PrV vaccine induced enhanced levels of serum PrV-specific IgG and its IgG2 isotype, compared to administration of S. enterica serovar Typhimurium harboring the empty vector. Furthermore, S. enterica serovar Typhimurium expressing swIL-18 mounted Th1-biased cellular immune responses against PrV antigen, as evaluated by the production of IFN-γ and IL-4 from peripheral blood mononuclear cells of piglets. Subsequently, Th1-biased immunity induced by S. enterica serovar Typhimurium expressing swIL-18 showed rapid response and rendered piglets displayed more alleviated clinical signs following the virulent PrV challenge. Also, this alleviation of clinical signs was further confirmed by the reduction of nasal excretion of PrV after challenge. The present study demonstrates the extended use of immunomodulatory functions of swIL-18 orally delivered by attenuated S. enterica serovar Typhimurium.     

Comparative assessment of purine nucleotides adenosine,guanosine and inosine monophosphates as functional supplements on growth and health performances of red sea bream,Pagrus major juvenile

Purine nucleotides regulate the cellular functions in the animal body. The current study evaluates the comparative efficacy of dietary purine nucleotides, that is, adenosine monophosphate (AMP), guanosine monophosphate (GMP) and inosine monophosphate (IMP) in red sea bream Pagrus major. Semi‐purified basal diet was formulated (Control, D1) containing 550 g/kg protein, supplemented with purine nucleotides AMP, GMP and IMP at their optimum supplementation level (2, 4 and 4 g/kg) to formulate the experimental diet groups D2, D3 and D4, respectively. Initial weight of 3.5 ± 0.01 g fish was randomly fed test diets in triplicate. After 56 days, % weight gain (p = .003), specific growth rate (p = .003) and apparent lipid digestibility (p = .04) were significantly higher in fish fed diet group D4 followed by D3 and D2. Supplemented groups showed significantly higher feed intake in comparison to control (p = .001). Supplemented groups showed significantly increased and decreased NBT (p = .003) and CAT (p = .003) activity, respectively. Fish fed IMP supplemented diets had significantly lower blood urea nitrogen (p = .04), glutamyl oxaloacetic transaminase (p = .04) and glutamic‐pyruvate transaminase (p = .001) followed by other supplemented groups. Supplemented diet groups showed enhanced stress resistance. Interestingly, D2 and D4 groups showed best oxidative stress status of fish. Therefore, these results indicated that among purine nucleotides, supplementation of IMP could be a more effective nucleotide as functional supplement in red sea bream diet.