Potent Skin Cancer Chemopreventing Activity of Some Novel Semi-synthetic Cembranoids from Marine Sources

In the course of our continuing research in development and evaluation of novel skin cancer chemopreventive agents from marine sources, five semi-synthetic cembranoids derived from the marine natural product sarcophine, isolated from the soft coral Sarcophyton glaucum, were synthesized and shown to exhibit a remarkable chemopreventive activity in the in-vitro Epstein Barr Virus Early Antigen (EBV-EA) activation assay. These compounds were assayed in vivo using the two-stage carcinogenesis test of mouse skin tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator, and 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter by topical administration. They showed potent inhibition of both percentage incidence of skin tumor as well as the multiplicity of skin tumors per mouse compared to untreated controls.     

Mapping QTLs in breeding for drought tolerance in maize (Zea mays L.)

Summary Grain yield in the maize (Zea mays L) plant is sensitive to drought in the period three weeks either side of flowering. Maize is well-adapted to the use of restriction fragment length polymorphisms (RFLPs) to identify a tight linkage between gene(s) controlling the quantitative trait and a molecular marker. We have determined the chromosomal locations of quantitative trait loci (QTLs) affecting grain yield under drought, anthesis-silking interval, and number of ears per plant. The F₃ families derived from the cross SD34(tolerant) × SD35 (intolerant) were evaluated for these traits in a two replicated experiment. RFLP analysis of the maize genome included non-radioactive DNA-DNA hybridization detection using chemiluminescence. To identify QTLs underlying tolerance to drought, the mean phenotypic performances of F₃ families were compared based on genotypic classification at each of 70 RFLP marker loci. The genetic linkage map assembled from these markers was in good agreement with previously published maps. The phenotypic correlations between yield and other traits were highly significant. In the combined analyses, genomic regions significantly affecting tolerance to drought were found on chromosomes 1,3,5,6, and 8. For yield, a total of 50% of the phenotypic variance could be explained by five putative QTLs. Different types of gene action were found for the putative QTLs for the three traits.     

Life history of Proprioseiopsis badri feeding on four eriophyid mite species (Acari: Phytoseiidae and Eriophyidae)

The influence of four eriophyid mite species as prey, Aceria dioscoridis, Aceria olivi, Aculops lycopersici and Cisaberoptus kenyae, on the biology and demographic parameters of the predatory mite Proprioseiopsis badri, was studied under laboratory conditions. Feeding on A. dioscoridis and A. olivi enhanced the development of P. badri, resulted in the longest mean generation time and were the most suitable foods for the oviposition of the predator, as exhibited by the highest fecundity, net reproductive rate and gross reproductive rate. Preying on A. lycopersici gave the lowest fecundity, net and gross reproductive rates and finite rate of increase; therefore, this prey was the least suitable for the oviposition of P. badri. Preying on A. dioscoridis and A. olivi produced higher intrinsic rates of increase, reproduction rates and finite rates of increase for the predator in comparison with A. lycopersici and C. kenyae, which had the lowest value. These differences in response to various eriophyid pests should be considered for the production of healthy cultures of P. badri.     

Detection of a Babesia sp. genotype closely related to marsupial-associated Babesia spp. in male Haemaphysalis shimoga from Sarawak,Malaysian Borneo

In this study, Babesia screening was conducted in 55 rodents and 160 tick samples collected from primary forests and an oil palm plantation in Sarawak, Malaysian Borneo. PCR targeting the 18S ribosomal DNA revealed the presence of Babesia spp. DNA detected in two questing male Haemaphysalis shimoga ticks collected from the oil palm plantation. Sequence analysis revealed that both sequences were identical and had 98.6% identity to a Babesia macropus sequence obtained from Eastern grey kangaroos (Macropus giganteus) in Australia. Phylogenetic tree revealed clustering with marsupial-associated Babesia spp. in the Babesia sensu stricto clade. Whether or not H. shimoga is the competent vector and the importance of the Babesia sp. detected in this study warrants more investigation.     

Do faba bean (Vicia faba L.) accessions from environments with contrasting seasonal moisture availabilities differ in stomatal characteristics and related traits?

Drought is a major constraint to faba bean (Vicia faba L.) production, and there are many mechanisms by which leaves can regulate water loss. Our primary objective was to test if the origin of the faba bean accessions, from drought-prone and non-drought-prone environments, was associated with differences in measurable aspects of stomatal morphology and physiology related to water use. Two sets, each consisting of 201 faba bean accessions, were chosen from environments with contrasting seasonal moisture profiles following the focused identification of germplasm strategy (FIGS), and then screened under well watered conditions. From these, two subsets of 10 accessions each were chosen to test for differences in response to drought. Parameters related to stomatal function and water status were measured. The dry-adapted set had bigger stomata, higher leaf relative water content (LRWC) and cooler leaves under well watered conditions. Stomatal density and stomatal area per unit area of leaflet were negatively correlated with gas exchange parameters and positively correlated with intrinsic water use efficiency. Drought caused stomatal densities to increase in the dry set while stomatal length decreased in both sets. The moisture deficit was sufficient to decrease gas exchange in both sets to similar levels, but the dry-adapted set maintained warmer leaves and a higher LRWC that showed no significant correlations with leaf morphology or gas exchange, demonstrating more effective stomatal regulation. The results also support that collection site data from the environment where genetic resources are collected can be used as indicators of adaptive traits in an herbaceous annual species.     

Effects of florfenicol on the immune responses and the interferon-inducible genes in broiler chickens under the impact of E. coli infection

Florfenicol (FFC) as a chloramphenicol’s derivative is a special broad-spectrum antibiotic that was used in veterinary clinics. In the present study, we investigated the effect of different doses of FFC on the humoral immune response of broiler chickens to Newcastle disease virus (NDV) vaccine under the impact of E. coli infection. In addition, the expression of the interferon-inducible genes (IRF7, 2′-5′OAS and Mx1) were analyzed in the spleen tissue of these chickens using quantitative real-time PCR (qRT-PCR). The non-treated group with FFC and non-infected with E. coli had the highest immune responses against NDV compared with the FFC treated groups. In the case of E. coli infection, the group treated with FFC (30 mg/Kg BWt) showed lower NDV HI and IgG ELISA Ab levels compared to the group treated with FFC (60 mg/Kg BWt). A dose dependent up-regulation was observed in the level of the interferon-alpha pathway related genes (IRF7 and 2′-5′OAS) in the FFC treated groups compared to the non-treated group. At the slaughter time, the numbers of adipocyte in the bone marrow were significantly higher with moderate atrophy of the hematopoietic lineages in the FFC treated birds compared to the non-treated birds. These results indicated that this FFC dosage dependent increase in the humoral immune responses against NDV vaccine could be attributed to its efficient therapeutic effect on the E. coli infection. However, the increase in the FFC dosage can negatively but temporarily affect the chicken body weights. Additionally, it can exert up regulation effect on the chicken innate immune response with moderate hypoplasia of the bone marrow cells.     

Focused identification of germplasm strategy (FIGS) detects wheat stem rust resistance linked to environmental variables

Recent studies have shown that novel genetic variation for resistance to pests and diseases can be detected in plant genetic resources originating from locations with an environmental profile similar to the collection sites of a reference set of accessions with known resistance, based on the Focused Identification of Germplasm Strategy (FIGS) approach. FIGS combines both the development of a priori information based on the quantification of the trait-environment relationship and the use of this information to define a best bet subset of accessions with a higher probability of containing new variation for the sought after trait(s). The present study investigates the development strategy of the a priori information using different modeling techniques including learning-based techniques as a follow up to previous work where parametric approaches were used to quantify the stem rust resistance and climate variables relationship. The results show that the predictive power, derived from the accuracy parameters and cross-validation, varies depending on whether the models are based on linear or non-linear approaches. The prediction based on learning techniques are relatively higher indicating that the non-linear approaches, in particular support vector machine and neural networks, outperform both principal component logistic regression and generalized partial least squares. Overall there are indications that the trait distribution of resistance to stem rust is confined to certain environments or areas, whereas the susceptible types appear to be limited to other areas with some degree of overlapping of the two classes. The results also point to a number of issues to consider for improving the predictive performance of the models.     

Wirkungen von zwei Antihäutungs-Substanzen auf die Raupen von Spodoptera littoralis (Boisd.)

Effect of two antimoulting compounds against the larvae of Spodoptera littoralis (Boisd.) Dc 201 and 202 are representatives of a new class of insecticides. Susceptibily of three instars ofSpodopteram littoralis (i.e., 1st, 3rd, and 6th) is demonstrated. Their insecticidal activity demmonstrates itself as a failure to moulte or pupate, resulting in death. Treated larvae remained seemingly unaffected until they had entered the apolytic stage preceding the actual sheding of the exuvia.Dc 202 was more active and more persistant on treated cotton plants than DC 201, particularly at the lower oncentration; the residual activity of the former compound extexded much longer than 15 days.