The Comparative Susceptibility of the Diamondback Moth Plutella xylostella and Some Other Major Lepidopteran Pests of Brassica Crops to a Range of Baculoviruses

The susceptibility of larvae of the Diamondback moth (DBM), Plutella xylostella to infection by three baculoviruses was evaluated in the laboratory using a microdroplet feeding assay. The viruses tested were a granulovirus (GV), originally isolated in Taiwan from P. xylostella larvae (Px GV-Taiwan); the nucleopolyhedrovirus (NPV) from Galleria mellonella (Gm NPV), and the NPV from Autographa californica (Ac NPV). Neonate P. xylostella larvae were susceptible to infection by all three viruses. In an extensive series of bioassays carried out over a 21-month period, LD 50S for neonate DBM larvae ranged from 1.0-8.9 viral occlusion bodies (OB) for Px GV-Taiwan, and 9.5-30.2 OB for Gm NPV and Ac NPV. LT 50S for the three viruses ranged from 3.8-6.0 days at 27 C, with Gm NPV having a significantly shorter LT 50 than the other two viruses. Second and third instar larvae of P. xylostella were significantly less susceptible to infection by Px GV-Taiwan (LD 50 s ranging from 18-57 OB/larva) than were neonate larvae. Gm NPV also initiated infection in several other lepidopterous pest species that colonize brassica crops. In particular, neonate Crocidolomia binotalis larvae proved highly susceptible to Gm NPV, with mean LD 50 s ranging from 2.1 to 9.3 OB/larva and a mean LT 50 of 4.8 days at a dose of 8.08 OB. Heliothis virescens neonate larvae were also highly susceptible to Gm NPV (LD 50 , 7.1 OB), but Mamestra brassicae larvae were less so (LD 50 , 80-270 OB). The results of the bioassays suggest that Px GV-Taiwan is highly infective and could be developed as a selective microbial pesticide for DBM. While Gm NPV has a higher LD 50 in DBM larvae, its wider host range may be of considerable value in situations where DBM occurs on cruciferous crops together with a complex of other lepidopterous pests.     

Biological kinetics evaluation of anaerobic stabilization pond treatment of palm oil mill effluent

Biological kinetic (bio-kinetic) study of the anaerobic stabilization pond treatment of palm oil mill effluent (POME) was carried out in a laboratory anaerobic bench scale reactor (ABSR). The reactor was operated at different feed flow-rates of 0.63, 0.76, 0.95, 1.27, 1.9 and 3.8 l of raw POME for a day. Chemical oxygen demand (COD) as influent substrates was selected for bio-kinetic study. The investigation showed that the growth yield (Y_G), specific biomass decay (b), maximum specific biomass growth rate (μ_max), saturation constant (K_s) and critical retention time (Θ_c) were in the range of 0.990 g VSS/g COD_removed day, 0.024 day⁻¹, 0.524 day⁻¹, 203.433 g COD l⁻¹ and 1.908 day, respectively.     

Competition amongst Eph receptors regulates contact inhibition of locomotion and invasiveness in prostate cancer cells

Metastatic cancer cells typically fail to halt migration on contact with non-cancer cells. This invasiveness is in contrast to normal mesenchymal cells that retract on contact with another cell. Why cancer cells are defective in contact inhibition of locomotion is not understood. Here, we analyse the dynamics of prostate cancer cell lines co-cultured with fibroblasts, and demonstrate that a combinatorial code of Eph receptor activation dictates whether cell migration will be contact inhibited. The unimpeded migration of metastatic PC-3 cells towards fibroblasts is dependent on activation of EphB3 and EphB4 by ephrin-B2, which we show activates Cdc42 and cell migration. Knockdown of EphB3 and EphB4 restores contact inhibition of locomotion to PC-3 cells. Conversely, homotypic collisions between two cancer cells results in contact inhibition of locomotion, mediated by EphA-Rho-Rho kinase (ROCK) signalling. Thus, the migration of cancer cells can switch from restrained to invasive, depending on the Eph-receptor profile of the cancer cell and the reciprocal ephrin ligands expressed by neighbouring cells.     

Duplicate <Emphasis Type="Italic">dmbx1</Emphasis>genes regulate progenitor cell cycle and differentiation during zebrafish midbrain and retinal development

Background  

The Dmbx1 gene is important for the development of the midbrain and hindbrain, and mouse gene targeting experiments reveal that this gene is required for mediating postnatal and adult feeding behaviours. A single Dmbx1 gene exists in terrestrial vertebrate genomes, while teleost genomes have at least two paralogs. We compared the loss of function of the zebrafish dmbx1a and dmbx1b genes in order to gain insight into the molecular mechanism by which dmbx1 regulates neurogenesis, and to begin to understand why these duplicate genes have been retained in the zebrafish genome.     

Adipocyte/macrophage fatty acid binding proteins control integrated metabolic responses in obesity and diabetes

Fatty acid binding proteins (FABPs) are cytosolic fatty acid chaperones whose biological role and mechanisms of action are not well understood. Here, we developed mice with targeted mutations in two related adipocyte FABPs, aP2 and mal1, to resolve their role in systemic lipid, glucose, and energy metabolism. Mice lacking aP2 and mal1 exhibited a striking phenotype with strong protection from diet-induced obesity, insulin resistance, type 2 diabetes, and fatty liver disease. These mice have altered cellular and systemic lipid transport and composition, leading to enhanced insulin receptor signaling, enhanced muscle AMP-activated kinase (AMP-K) activity, and dramatically reduced liver stearoyl-CoA desaturase-1 (SCD-1) activity underlying their phenotype. Taken together with the previously reported strong protection against atherosclerosis, these results demonstrate that adipocyte/macrophage FABPs have a robust impact on multiple components of metabolic syndrome, integrating metabolic and inflammatory responses in mice and constituting a powerful target for the treatment of these diseases.     

Genetic Diversity and Pathogenic Variability of Colletotrichum truncatum Causing Anthracnose of Pepper in Malaysia

Colletotrichum truncatum was initially described from pepper and has been reported to infect 180 host genera in 55 plant families worldwide. Samples were collected from pepper plants showing typical anthracnose symptoms. Diseased samples after isolation were identified as C. truncatum based on morphological characters and ITS‐rDNA and β‐tubulin sequence data. Intersimple sequence repeat (ISSR) markers were used to estimate genetic diversity in C. truncatum from Malaysia. A set of 3 ISSR primers revealed a total 26 allele from the amplified products. Cluster analysis with UPGMA method clustered C. truncatum isolates into two main groups, which differed with a distance of 0.64. However, the genetic diversity of C. truncatum isolates showed correlation between genetic and geographical distribution, but it failed to reveal a relationship between clustering and pathogenic variability. Phylogenetic analyses discriminated the C. truncatum isolates from other reference Colletotrichum species derived from GenBank. Among the morphological characters, shape, colour of colony and growth rate in culture were partially correlated with the ISSR and phylogenetic grouping. Pathogenicity tests revealed that C. truncatum isolates were causal agents for pepper anthracnose. In the cross‐inoculation assays, C. truncatum isolates were able to produce anthracnose symptoms on tomato, eggplant, onion, lettuce and cabbage. A pathogenicity and cross‐inoculation studies indicated the potential of C. truncatum for virulence and dominancy on plant resistance.     

Efficient Transformation of Oil Palm Protoplasts by PEG-Mediated Transfection and DNA Microinjection

Background

Genetic engineering remains a major challenge in oil palm (Elaeis guineensis) because particle bombardment and Agrobacterium-mediated transformation are laborious and/or inefficient in this species, often producing chimeric plants and escapes. Protoplasts are beneficial as a starting material for genetic engineering because they are totipotent, and chimeras are avoided by regenerating transgenic plants from single cells. Novel approaches for the transformation of oil palm protoplasts could therefore offer a new and efficient strategy for the development of transgenic oil palm plants.

Methodology/Principal Findings

We recently achieved the regeneration of healthy and fertile oil palms from protoplasts. Therefore, we focused on the development of a reliable PEG-mediated transformation protocol for oil palm protoplasts by establishing and validating optimal heat shock conditions, concentrations of DNA, PEG and magnesium chloride, and the transfection procedure. We also investigated the transformation of oil palm protoplasts by DNA microinjection and successfully regenerated transgenic microcalli expressing green fluorescent protein as a visible marker to determine the efficiency of transformation.

Conclusions/Significance

We have established the first successful protocols for the transformation of oil palm protoplasts by PEG-mediated transfection and DNA microinjection. These novel protocols allow the rapid and efficient generation of non-chimeric transgenic callus and represent a significant milestone in the use of protoplasts as a starting material for the development of genetically-engineered oil palm plants.     

The investigation of the secondary structure propensities and free-energy landscapes of peptide ligands by replica exchange molecular dynamics simulations

The conformational states of two peptide sequences that bind to staphylococcal enterotoxin B are sampled by replica exchange molecular dynamic (REMD) simulations in explicit water. REMD simulations were treated with 52 replicas in the range of 280–501 K for both peptides. The conformational ensembles of both peptides are dominated by random coil, bend and turn structures with a small amount of helical structures for each temperature. In addition, while an insignificant presence of β-bridge structures were observed for both peptides, the β-sheet structure was observed only for peptide 3. The results obtained from simulations at 300 K are consistent with the experimental results obtained from circular dichroism spectroscopy. From the analysis of REMD results, we also calculated hydrophobic and hydrophilic solvent accessible surface areas for both peptides, and it was observed that the hydrophobic segments of the peptides tend to form bend or turn structures. Moreover, the free-energy landscapes of both peptides were obtained by principal component analysis to understand how the secondary structural properties change according to their complex space. From the free-energy analysis, we have found several minima for both peptides at decreased temperature. For these obvious minima of both peptides, it was observed that the random coil, bend and turn structures are still dominant and the helix, β-bridge or β-sheet structures can appear or disappear with respect to minima. On the other hand, when we compare the results of REMD with conventional MD simulations for these peptides, the configurations of peptide 3 might be trapped in energy minima during the conventional MD simulations. Hence, it can be said that the REMD simulations have provided a sufficiently high sampling efficiency.     

Evaluation of Gamma-Radiation Inactivation of a Bioterrorism Agent, <Emphasis Type="Italic">Bacillus anthracis</Emphasis> Spores,on Different Materials

Decontamination of suspected packages, such as sealed envelopes, liquids and tools that are likely contaminated with biological agents is of great importance. In this study, we aimed to determine the gamma radiation dose required for the decontamination of paper, fabric and liquid materials without causing any damage to the structure of these materials. Each study group included 11 pieces of paper, fabric and sterile saline contaminated with 0.8 × 10⁵ virulent Bacillus anthracis (B. anthracis) spores. These specimens were exposed to doses of 5.49, 11.58, 17.21, 21.75, 27 and 33.1 kilogray (kGy) of gamma radiation from a cobalt-60 source. After irradiation of all the samples, a viability assessment of the B. anthracis spores was performed. It was found that full decontamination was achieved with 11.58 kGy on the paper samples and 17.21 kGy on the fabric and liquid samples. It was concluded that a dose of 20 kGy of gamma radiation may be recommended for the inactivation of B. anthracis for some surfaces when especially sensitive and valuable materials cannot be wet decontaminated were exposed. In addition, serologic and molecular assays of the suspected packets can be performed for forensic purposes without damaging existing evidence in a bioterror incident.