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。     

Male fertility attitudes: a neglected dimension in Nigerian fertility research

A sample of 202 male Nigerians enrolled in colleges and graduate schools in the state of Kansas were surveyed to determine their perceptions of population problems in Nigeria; attitudes toward family planning, divorce, and male children; and attitudes toward family size. A major limitation of Nigerian-based fertility research has been the neglect of the role of men in couples' reproductive behavior. The majority of Nigerian students surveyed in this study did not think overpopulation is an impending crisis in Nigeria: 40% thought there are just enough people and 13% indicated there are not enough people. 53% supported the concept of a government population policy, but 67% felt the government should not interfere with family size decisions. Although 84% endorsed the idea that family planning services and information should be available, 69% felt women should not practice family planning without the consent of their husbands. 43% believed a man should divorce his wife if the woman is infertile, unable to produce a male child, or unable to bear the number of children demanded by her husband; in addition, 35% indicated a man should marry a second wife or continue to have children if the couple has 5 daughters and no son. In terms of the value of children, 62% stated that children are wealth or better than wealth, whereas 38% claimed that children use up wealth. Duration of stay in the US was inversely correlated with the number of children considered too many, and the number of male children already born was an important determinant of future family size expectations. In general, it appears that level of education and exposure to US standards do not have a major impact on fertility values among Nigerians, particularly the desire for male children. Educated Nigerian men are an important target for population education, however, because they dominate and control many of the structural, behavioral, and cultural dimensions of fertility behavior.     

Blood Group Antigens C,Lub and P1 May Have a Role in HIV Infection in Africans

Background

Botswana is among the world’s countries with the highest rates of HIV infection. It is not known whether or not this susceptibility to infection is due to genetic factors in the population. Accumulating evidence, however, points to the role of erythrocytes as potential mediators of infection. We therefore sought to establish the role, if any, of some erythrocyte antigens in HIV infection in a cross-section of the population.

Methods

348 (346 HIV-negative and 2 HIV-positive) samples were obtained from the National Blood Transfusion Service as residual samples, while 194 HIV-positive samples were obtained from the Botswana-Harvard HIV Reference Laboratory. Samples were grouped for twenty three antigens. Chi-square or Fischer Exact analyses were used to compare the frequencies of the antigens in the two groups. A stepwise, binary logistic regression was used to study the interaction of the various antigens in the light of HIV-status.

Results

The Rh antigens C and E were associated with HIV-negative status, while blood group Jk^a, P₁ and Lu^b were associated with HIV-positive status. A stepwise binary logistic regression analysis yielded group C as the most significant protective blood group while Lu^b and P₁ were associated with significantly higher odds ratio in favor of HIV-infection. The lower-risk-associated group C was significantly lower in Africans compared to published data for Caucasians and might partially explain the difference in susceptibility to HIV-1.

Conclusion

The most influential antigen C, which also appears to be protective, is significantly lower in Africans than published data for Caucasians or Asians. On the other hand, there appear to be multiple antigens associated with increased risk that may override the protective role of C. A study of the distribution of these antigens in other populations may shed light on their roles in the HIV pandemic.     

A deletion variant study of the functional role of the Salmonella flagellin hypervariable domain region in motility

The eubacterial flagellum is a complex structure with an elongated extracellular filament that is composed primarily of many subunits of a flagellin protein. The highly conserved N and C termini of flagellin are important in its export and self-assembly, whereas the middle sequence region varies greatly in size and composition in different species and is known to be deletion-tolerant. In Salmonella typhimurium phase 1 flagellin, this "hypervariable" region encodes two solvent-exposed domains, D2 and D3, that form a knob-like feature on flagella fibers. The functional role of this structural feature in motility remains unclear. We investigated the structural and physiological role of the hypervariable region in flagella assembly, stability and cellular motility. A library of random internal deletion variants of S. typhimurium flagellin was constructed and screened for functional variants using a swarming agar motility assay. The relative cellular motility and propulsive force of ten representative variants were determined in semi-solid and liquid medium using colony swarming motility assays, video microscopy and optical trapping of single cells. All ten variants exhibited diminished motility, with varying extents of motility observed for internal deletions less than 75 residues and nearly complete loss of motility for deletions greater than 100 residues. The mechanical stability of the variant flagella fibers also decreased with increasing size of deletion. Comparison of the variant sequences with the wild-type sequence and structure indicated that all deletions involved loss of hydrophobic core residues, and removal of both partial and complete segments of secondary structure in the D2 and D3 domains. Homology modeling predicted disruptions of secondary structures in each variant. The hypervariable region D2 and D3 domains appear to stabilize the folded conformation of the flagellin protein and contribute to the mechanical stability and propulsive force of the flagella fibers.     

Diabetes mellitus caused by mutations in human insulin: analysis of impaired receptor binding of insulins Wakayama,Los Angeles and Chicago using pharmacoinformatics

Several naturally occuring mutations in the human insulin gene are associated with diabetes mellitus. The three known mutant molecules, Wakayama, Los Angeles and Chicago were evaluated using molecular docking and molecular dynamics (MD) to analyse mechanisms of deprived binding affinity for insulin receptor (IR). Insulin Wakayama, is a variant in which valine at position A3 is substituted by leucine, while in insulin Los Angeles and Chicago, phenylalanine at positions B24 and B25 is replaced by serine and leucine, respectively. These mutations show radical changes in binding affinity for IR. The ZDOCK server was used for molecular docking, while AMBER 14 was used for the MD study. The published crystal structure of IR bound to natural insulin was also used for MD. The binding interactions and MD trajectories clearly explained the critical factors for deprived binding to the IR. The surface area around position A3 was increased when valine was substituted by leucine, while at positions B24 and B25 aromatic amino acid phenylalanine replaced by non-aromatic serine and leucine might be responsible for fewer binding interactions at the binding site of IR that leads to instability of the complex. In the MD simulation, the normal mode analysis, rmsd trajectories and prediction of fluctuation indicated instability of complexes with mutant insulin in order of insulin native insulin < insulin Chicago < insulin Los Angeles < insulin Wakayama molecules which corresponds to the biological evidence of the differing affinities of the mutant insulins for the IR.     

Christia vespertilionis extract induced antiproliferation and apoptosis in breast cancer (MCF7) cells

Molecular Biology Reports - C. vespertiliomis extracts were evaluated for antiproliferative and apoptosis effect on breast cancer (MCF7) cells. The leaves extracts were analysed for its...