The transformer genes in the fig wasp Ceratosolen solmsi provide new evidence for duplications independent of complementary sex determination.

Transformer (tra) is the key gene that turns on the sex-determination cascade in Drosophila melanogaster and in some other insects. The honeybee Apis mellifera has two duplicates of tra, one of which (complementary sex determiner, csd) is the primary signal for complementary sex-determination (CSD), regulating the other duplicate (feminizer). Two tra duplicates have been found in some other hymenopteran species, resulting in the assumption that a single ancestral duplication of tra took place in the Hymenoptera. Here, we searched for tra homologues and pseudogenes in the Hymenoptera, focusing on five newly published hymenopteran genomes. We found three tra copies in the fig wasp Ceratosolen solmsi. Further evolutionary and expression analyses also showed that the two duplicates (Csoltra-B and Csoltra-C) are under positive selection, and have female-specific expression, suggesting possible sex-related functions. Moreover, Aculeata species exhibit many pseudogenes generated by lineage-specific duplications. We conclude that phylogenetic reconstruction and pseudogene screening provide novel evidence supporting the hypothesis of independent duplications rather an ancestral origin of multiple tra paralogues in the Hymenoptera. The case of C. solmsi is the first example of a non-CSD species with duplicated tra, contrary to the previous assumption that derived tra paralogues function as the CSD locus.

A modified ferric tannate method for visualizing a blood vessel and its usage in the study of spinal cord injury.

STUDY DESIGN: To develop a method for the study of spinal cord injury (SCI) that can visualize the blood vessels and is compatible with hematoxylin and eosin (HE) staining and immunohistochemical techniques. OBJECTIVE: Visualization of the vascular changes is important for the study of SCI. The original ferric tannate method can stain the spinal cord vasculature to its terminals, but the diffuse tannate precipitates spoil the delicacy of the picture. More importantly, it is incompatible with HE staining and immunohistochemical techniques, which is crucial for the study of SCI. We thus aimed to develop a modified ferric tannate method that could meet the requirement for the study of SCI. SETTING: This study was carried out in China. METHODS: The original ferric tannate method involves a two-step procedure: intravascular perfusion of tannic acid, followed by soaking the tissue sections in a solution of ferric chloride. In the modified method both chemicals were delivered through perfusion. RESULTS: In the original method, diffuse ferric tannate precipitates blurred the profile of the vessels. More importantly, it was incompatible with either HE or immunostaining methods. Our modified method stained the blood vessels with clean background and was compatible with both HE staining and immunohistochemical techniques. CONCLUSION: The modified method is far superior to the original method and meets the requirement for the study of SCI.

Biosensor binding assay of BmK AS-1, a novel Na+ channel-blocking scorpion ligand on rat brain synaptosomes.

The pharmacological binding of BmK AS-1, a novel Na+ channel-specific ligand purified from Chinese scorpion Buthus martensi Karsch (BmK), has been investigated by biosensor assay. The results showed a fast association rate constant (1.14 x 10(4) M(-1) s(-1)) but a very slow dissociation rate constant (3.24 x 10(-5) s(-1)) for BmK AS-1 binding to the Na+ channel on rat brain synaptosomes. The binding of BmK AS-1 to rat brain synaptosomes could be partially competed by BmK IT2, a depressant insect-selective toxin, but not by BmK I, an alpha-like toxin from the same venom. It was thus further demonstrated that BmK AS-1 might bind to a distinct receptor site, which was partially overlapping that for BmK IT2, but different from that of BmK I on rat brain Na+ channels.

Characterization of four distinct monoclonal antibodies specific to BmK AS-1, a novel scorpion bioactive polypeptide.

Four monoclonal antibodies designed as 2#, 3#, 4# and 5# have been raised against a novel bioactive polypeptide BmK AS-1 purified from the Chinese scorpion Buthus martensi Karsch. All of these antibodies exhibited specific affinity with antigen by ELISA and Biosensor assay. Western blot analysis showed that 3# and 4# were able to recognize the denatured antigen, but not 2# and 5#. These antibodies could cross-react with BmK AS, but not with other types of BmK neurotoxins such as BmK I (an alpha-like toxin) and BmK IT (an excitatory insect-selective toxin), and in which only 5# can partially react with BmK IT2 (a depressant insect-selective toxin). Immunocytochemical staining demonstrated that 3#, 4# and 5# antibodies can visualize the antigen bound to the membrane of SK-N-SH neuroblast cells, with the exception of 2#. This suggests that either conformation alteration of receptor binding might be prone to nonvisualization or the epitope recognized by antibody 2# might be overlapped with receptor binding sites of antigen. The antibodies developed in the study should provide powerful new tools for investigating the structure/function relationship and pharmacological mechanism of scorpion neurotoxins.

[Subtypes and functions of voltage-gated Na+ channel].

Since 1990s, the research on voltage-gated sodium channels have got rapid progress by the use of molecular biological and electrophysiological recording techniques. This communication presents a brief review on mammalian sodium channel involving classification, distribution, and mechanisms of expression regulation of various subtypes in the central and peripheral nervous system and other nonexcitable tissues.

[A serological study on the infection of Helicobacter pylori among children].

Using ELISA method, anti-H. pylori IgG and IgM were detected in 181 sera from patients (aged 2-14 years) complaining of repeated midepigastical pain and 152 sera of controls. The positive rate of anti-H, pylori IgG in the patients was 53%, significantly higher than those of control groups (34.6%-35%), (P < 0.05). The presence of anti-H. pylori IgG in serum can assist in the diagnosis of H. pylori, but can not indicate the existence of H. pylori. There were no evident relationships between level of antibodies (anti-H. pylori IgG and IgM) and the degree of H. pylori infection, or the duration of disease. Children's H. pylori infection increases with age. Elder children have the same positive rate of anti-H. pylori IgG as adults. Hence, eradication of H. pylori infection should be focused not only on adults but also on children.

[Immobilized Ni(2+)-IDA metal chelating affinity membrane chromatography for purification of commercial human serum albumin].

Further purification of commercial human serum albumin was studied on immobilized Ni(2+)-IDA composite membrane cartridge. Effect of pH on HSA binding capacity was examined. A lot of impurities in the commercial HSA had been removed by a single step purification with a recovery of more than 85% of the protein bound on membrane cartridge. The purified HSA was of comparable purity of that from Sigma company analyzed by capillary electrophoresis. The nickel ion retained in the protein solution could be removed efficiently with the N, N, N'-tris (carboxymethyl) ethylenediamine chelating membrane cartridge.