Molecular Species Identification of Spiny Lobster Phyllosoma Larvae of the Genus Panulirus from the Northwestern Pacific

To identify lobster phyllosoma larvae of the genus Panulirus occurring in waters adjacent to Japan, genetic variation within and between 10 Indo-Pacific lobster species was investigated using restriction fragment length polymorphism (RFLP) analysis for the 1300-base pair mitochondrial cytochrome oxidase I (COI) gene. RFLP analysis using two endonucleases (AluI and TaqI) enabled discrimination of all species, including the P. longipes complex. The diagnostic DNA markers, supplemented with nucleotide sequence analysis, were applied to 44 mid- to late-stage phyllosoma larvae (7.4 to 27.7 mm in body length) collected in the northwestern Pacific. These samples were unexpectedly variable in species composition, comprising P. japonicus (n = 16), P. longipes bispinosus (21), P. longipes longipes (1), P. “aka” (1), and P. penicillatus (5). Comparison of larval size at similar stages revealed that P. l. bispinosus larvae were significantly larger than P. japonicus.     

Schistosome infection intensity is inversely related to auto-reactive antibody levels

In animal experimental models, parasitic helminth infections can protect the host from auto-immune diseases. We conducted a population-scale human study investigating the relationship between helminth parasitism and auto-reactive antibodies and the subsequent effect of anti-helminthic treatment on this relationship. Levels of antinuclear antibodies (ANA) and plasma IL-10 were measured by enzyme linked immunosorbent assay in 613 Zimbabweans (aged 2-86 years) naturally exposed to the blood fluke Schistosoma haematobium. ANA levels were related to schistosome infection intensity and systemic IL-10 levels. All participants were offered treatment with the anti-helminthic drug praziquantel and 102 treated schoolchildren (5-16 years) were followed up 6 months post-antihelminthic treatment. ANA levels were inversely associated with current infection intensity but were independent of host age, sex and HIV status. Furthermore, after allowing for the confounding effects of schistosome infection intensity, ANA levels were inversely associated with systemic levels of IL-10. ANA levels increased significantly 6 months after anti-helminthic treatment. Our study shows that ANA levels are attenuated in helminth-infected humans and that anti-helminthic treatment of helminth-infected people can significantly increase ANA levels. The implications of these findings are relevant for understanding both the aetiology of immune disorders mediated by auto-reactive antibodies and in predicting the long-term consequences of large-scale schistosomiasis control programs.     

Function of RNA-binding protein Musashi-1 in stem cells

Musashi is an evolutionarily conserved family of RNA-binding proteins that is preferentially expressed in the nervous system. The first member of the Musashi family was identified in Drosophila. This protein plays an essential role in regulating the asymmetric cell division of ectodermal precursor cells known as sensory organ precursor cells through the translational regulation of target mRNA. In the CNS of Drosophila larvae, however, Musashi is expressed in proliferating neuroblasts and likely has a different function. Its probable mammalian homologue, Musashi-1, is a neural RNA-binding protein that is strongly expressed in fetal and adult neural stem cells (NSCs). Mammalian Musashi-1 augments Notch signaling through the translational repression of its target mRNA, m-Numb, thereby contributing to the self-renewal of NSCs. In addition to its functions in NSCs, the role of mammalian Musashi-1 protein in epithelial stem cells, including intestinal and mammary gland stem cells, is attracting increasing interest.     

Absence of strand bias for deletion mutagenesis during chromosomal leading and lagging strand replication in Escherichia coli

Investigations were carried out to determine whether both DNA strands involved in Escherichia coli chromosomal DNA replication are replicated with similar accuracy. Experiments consisted of measuring the forward mutation rate from tonB(+) to tonB(-) in pairs of polA deficient strains in which the chromosomal target gene tonB was oriented in the two possible directions relative to the origin of replication, oriC. Within these pairs, the tonB sequence would be subjected to leading strand replication in one orientation and to lagging strand replication in the other. The most common tonB mutations in the polA1 strain were deletions followed by frameshifts. Among the deletions, a strong hotspot site with a 13-base deletion in the polA1 strains accounted for 18 of the 33 deletions in the one orientation, and 31 of the 58 deletions in the other. The results suggested that the two strands were replicated with equal or similar accuracy for deletion formation.     

Molecular cloning and functional expression of nucleolar phospholipid hydroperoxide glutathione peroxidase in mammalian cells

We cloned a full-length cDNA for phospholipid hydroperoxide glutathione peroxidase (PHGPx) including exon Ib from rat and mouse testis. The nuclear signal sequence of the N terminal of rat nuclear PHGPx possessed a different sequence from that previously reported for rat sperm nuclei GPx (SnGPx). Expression of this PHGPx-YFP (yellow fluorescent protein) fusion protein including a novel nuclear signal sequence was exclusively localized in nucleolus; although YFPs fused with only a novel nuclear signal sequence were distributed in the whole nucleus, indicating that preferential translocation of nucleolar PHGPx into nucleoli was required for the nuclear signal sequence and internal sequence of PHGPx. Low level expression of nucleolar PHGPx was detected in several tissues, but the expression of nucleolar PHGPx was extensively high in testis. Immunohistochemical analysis with anti-nucleolar PHGPx indicated that expression of nucleolar PHGPx was observed in the nucleoli in the spermatogonia, spermatocyte, and spermatid. Overexpression of 34kDa nucleolar PHGPx in RBL2H3 cells significantly suppressed cell death induced by actinomycin D and doxorubicin that induced damage in the nucleolus. These results indicated that nucleolar PHGPx plays an important role in prevention of nucleolus from damage in mammalian cells.     

Incomplete proviral genome of mouse mammary tumour virus is present on chromosome Y of NIH Swiss and some genetically related mouse strains.

An incomplete proviral genome of endogenous mammary tumour virus (MMTV) was found in DNA of several strains of mice. This MMTV-related sequence was assigned to the Y chromosome since it was clearly observed in male mice only. This MMTV provirus contained a sequence related to LTR (long terminal repeat), but not to gag-pol and env genes. NFS, NIH Swiss/S, STS/A, and DD/Tbr mice have this sequence but BALB/cHeA, SHN, SLN, C57BL/6NJcl, C3H/HeNJcl and CBA/JJcl mice are negative. In the strains containing this sequence, a DNA test for the sequence makes it possible to easily distinguish the DNAs of male or female mice.     

A new immobilization technique of whole cells and enzymes with colloidal silica and alginate

A mixed gel composed of colloidal silica and alginate (As gel) was prepared for the immobilization of enzymes or microorganisms. The physical strength of AS gel increased with the amount of colloidal silica. The ethanol production rate of Saccharomyces cerevisiae (IFO 0224) immobilized in AS gel was higher than in alginate gel (Al gel) in the early phase of growth. At a concentration of glucose of more than 10%, the ethanol production of immobilized yeast in AS gel was higher than in Al gel. Any difference was not recognized in the diffusion coefficient of glucose between AS and Al gels. The AS gel had an ability to retain proteins such as bovine serum albumin and gamma-globulin. The alkaline protease and beta-galactosidase in AS gel continued their function for a long time, but those immobilized in Al gel did not. Immobilized beta-galactosidase in AS gel had a higher thermal stability than in Al gel or free enzymes.     

Association of neutral α-glucosidase with cytoplasmic granules of peritoneal macrophages

A neutral α-glucosidase (EC 3.2.1.20) activity was shown to be associated with granules which are sedimentable at 10 000 g after differential centrifugation of mouse peritoneal macrophage homogenates. When the post-nuclear supernatant was centrifuged in a sucrose density gradient, high activities for neutral α-glucosidase and β-glucuronidase (EC 3.2.1.31) were detected in the bottom fractions because of aggregation of the granules. Neutral α-glucosidase-containing granules were completely disaggregated by the addition of 20 units/ml of heparin and 10 mM Tris-HCl (pH 7.2), which caused only a partial disaggregation of β-glucuronidase-containing granules. The addition of a high concentration of heparin, Tris buffer, or KCl to the gradient gave the same patterns of disaggregation of the granules. Under the condition in which about 50% of the total β-glucuronidase activity was released into the medium, depending on phagocytosis, very little α-glucosidase was released. These observations suggested that neutral α-glucosidase may localize in non-lysosomal granules.