Evaluation of responses of five cowpea (Vigna unguiculata (L.) Walp.) varieties to field infestation by major insect pests of cowpea

The study was conducted to evaluate yield response of five cowpea (Vigna unguiculata (L.) Walp.) varieties to field infestation and damage by major insect pests of cowpea. Three local varieties of cowpea, namely, Sokoto, Oloyin and Drum, and two International Institute of Tropical Agriculture (IITA) varieties, IT 90K-277-2 and IT90K-76, were planted on the Teaching and Research Farm of University of Agriculture, Abeokuta (UNAAB), Ogun State, Nigeria in September, 2006 and repeated in September, 2007. The experiment was laid out in Randomised Complete Block Design in split plots arrangement. Insecticidal spray constitutes the main plot while variety was the sub-plot. The main plot size was 19.4 m × 19 m and each of the sub-plot was 2.4 m × 3 m. The space between sub-plots was 1 m. Data from the sprayed plots were significantly (P < 0.05) higher than the unsprayed ones in the two seasons. Irrespective of season, the unsprayed plot of IT 90K-277-2 has a significantly (P < 0.05) high incidence of Ootheca mutabilis. The local variety, “Drum” has the highest incidence of flower thrip – Megalurothrips sjostedti in the two planting seasons. The highest mean number of peduncles/plant and pods/plant was in “IT 90K-277-2”. In both seasons, “IT90K-76” has a significantly (P < 0.05) lower number of damaged seeds and pods and “Oloyin” a significantly (P < 0.05) higher mean number of total pod sucking bugs. The grain yield was in the order IT90K-76 > Oloyin > IT 90K-277-2 > Sokoto > Drum.     

Doubly linked,A-type proanthocyanidin trimer and other constituents of Ixora coccinea leaves and their antioxidant and antibacterial properties

Phytochemical investigation of the ethyl acetate fraction of the methanol extract of the leaves of Ixora coccinea led to the isolation and identification of an A-type trimeric proanthocyanidin epicatechin-(2β → O → 7, 4β → 8)–epicatechin-(5 → O → 2β, 6 → 4β)–epicatechin named ixoratannin A-2 along with seven known compounds, epicatechin, procyanidin A2, cinnamtannin B-1, and four flavon-3-ol rhamnosides viz: kaempferol-7-O-α-l-rhamnnoside, kaempferol-3-O-α-l-rhamnoside, quercetin-3-O-α-l-rhamnopyranoside, and kaempferol-3,7-O-α-l-dirhamnoside. The structures were elucidated by the application of IR, UV, MS, 1D-, and 2D-NMR spectroscopic analyses and by comparison with literature data. Antioxidant evaluation of isolated compounds revealed that ixoratannin A-2 and cinnamtannin B-1 were the most active compounds in DPPH, inhibition of lipid peroxidation and nitric oxide radical scavenging assays. Antibacterial activities were assessed by means of agar-diffusion assays using Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis. All tested compounds inhibited the growth of B. subtilis, while only epicatechin and quercetin-3-O-α-l-rhamnopyranoside inhibited the growth of E. coli.     

Synthesis and characterization of nickel(II) complexes bearing 2-(imidazol-2-yl)pyridines or 2-(pyridin-2-yl)phenanthroimidazoles/oxazoles and their polymerization of norbornene

Series of 2-R₁-6-(1-R₂-4,5-diphenyl-1H-imidazol-2-yl)pyridine (R₁ = R₂ = H, L1; R₁ = Me, R₂ = H, L2; R₁ = H, R₂ = Me, L3; R₁ = R₂ = Me, L4), 2-(6-R₁-pyridin-2-yl)-1H-phenanthro[9,10-d]imidazole (R₁ = H, L5; R₁ = Me, L6) and 2-(pyridin-2-yl)phenanthro[9,10-d]oxazole (L7) were synthesized and used to prepare their corresponding dihalonickel complexes (C1-C9). All organic compounds and nickel complexes were characterized by elemental and spectroscopic analyses. Molecular structures of C1, C4, C5 and C8 were confirmed by the single-crystal X-ray diffraction analysis. The single-crystal X-ray analysis revealed complex C1 as a distorted octahedral geometry, complex C4 as a distorted square pyramidal geometry, complex C5 as a distorted trigonal bipyramidal configuration, and complex C8 as a tetrahedral geometry. Upon activation with methylaluminoxane (MAO), the nickel complexes showed good activity towards norbornene polymerization through main additional and minor ring-opening metathesis. The reaction parameters such as norbornene concentration, reaction temperature and different coordinate environments caused by the ligands affected their catalytic performances.     

尼日利亚南部阿贝奥库塔地区冈比亚按蚊复合体的形态特征研究（双翅目：蚊科）

对采自尼日利亚南部城市阿贝奥库塔冈比亚按蚊复合体Anopheles gambiae complex的形态特征进行了研究。依据2005年8月至2006年7月灯诱捕获的364个冈比亚按蚊复合体标本,分别对它们的触角、翅、喙、前足、中足和后足6个部位的长度进行了测量,对月平均值进行回归分析,同时利用差异系数（co-efficient of difference,CD）进行近缘分析。分析显示,各特征的长度平均值雨季大于旱季,但是回归分析表明长度变化与季节不显著相关（P>0.05）。差异系数分析结果表明,仅触角长度和翅长显示此复合体为两个不同的种群(CD>1.28),而其他特征值表明为同一种群。因此,该研究结果提示触角长度及翅长对冈比亚按蚊复合体近缘种的区分有重要参考价值。     

High-level secretory expression of immunologically active intact antibody from the yeast Pichia pastoris

We have produced a functional murine antibody to dioxin in the culture medium of the methylotrophic yeast Pichia pastoris. Complementary DNA copies encoding the light () and heavy () chains of the dioxin monoclonal antibody, DD1, were each placed under the control of P.pastoris alcohol oxidase (AOX1) promoter and Saccharomyces cerevisiae -mating factor secretion signal sequence. The resulting expression cassettes were assembled into a single plasmid (pPICZDD1) to permit co-expression of both light and heavy chains of the antibody molecule. P.pastoris SMD1168 (pep4, his4) transformed with pPICZDD1 was able to secrete intact antibody into the culture medium. As high as 36 mg l^–1 of the antibody was produced in shake-flask cultures after 96-h induction with methanol. Functional analysis using immunoassay confirmed murine nature of the recombinant antibody and its ability to bind dioxin.     

A variable region within the genome of Streptococcus pneumoniae contributes to strain-strain variation in virulence

The bacterial factors responsible for the variation in invasive potential between different clones and serotypes of Streptococcus pneumoniae are largely unknown. Therefore, the isolation of rare serotype 1 carriage strains in Indigenous Australian communities provided a unique opportunity to compare the genomes of non-invasive and invasive isolates of the same serotype in order to identify such factors. The human virulence status of non-invasive, intermediately virulent and highly virulent serotype 1 isolates was reflected in mice and showed that whilst both human non-invasive and highly virulent isolates were able to colonize the murine nasopharynx equally, only the human highly virulent isolates were able to invade and survive in the murine lungs and blood. Genomic sequencing comparisons between these isolates identified 8 regions >1 kb in size that were specific to only the highly virulent isolates, and included a version of the pneumococcal pathogenicity island 1 variable region (PPI-1v), phage-associated adherence factors, transporters and metabolic enzymes. In particular, a phage-associated endolysin, a putative iron/lead permease and an operon within PPI-1v exhibited niche-specific changes in expression that suggest important roles for these genes in the lungs and blood. Moreover, in vivo competition between pneumococci carrying PPI-1v derivatives representing the two identified versions of the region showed that the version of PPI-1v in the highly virulent isolates was more competitive than the version from the less virulent isolates in the nasopharyngeal tissue, blood and lungs. This study is the first to perform genomic comparisons between serotype 1 isolates with distinct virulence profiles that correlate between mice and humans, and has highlighted the important role that hypervariable genomic loci, such as PPI-1v, play in pneumococcal disease. The findings of this study have important implications for understanding the processes that drive progression from colonization to invasive disease and will help direct the development of novel therapeutic strategies.     

The Ubiquitin Binding Region of the Smurf HECT Domain Facilitates Polyubiquitylation and Binding of Ubiquitylated Substrates

Mono- and polyubiquitylation of proteins are key steps in a wide range of biological processes. However, the molecular mechanisms that mediate these different events are poorly understood. Here, we employed NMR spectroscopy to map a non-covalent ubiquitin binding surface (UBS) on the Smurf ubiquitin ligase HECT domain. Analysis of mutants of the HECT UBS reveal that interfering with the UBS surface blocked Smurf-dependent degradation of its substrate RhoA in cells. In vitro analysis revealed that the UBS was not required for UbcH7-dependent charging of the HECT catalytic cysteine. Surprisingly, although the UBS was required for polyubiquitylation of both Smurf itself and the Smurf substrate RhoA, it was not required for monoubiquitylation. Furthermore, we show that mutating the UBS interfered with efficient binding of a monoubiquitylated form of RhoA to the Smurf HECT domain. Our findings suggest the UBS promotes polyubiquitylation by stabilizing ubiquitylated substrate binding to the HECT domain.