Analysis of eighteen deletion breakpoints in the parkin gene

Parkin mutations are responsible for the pathogenesis of autosomal-recessive juvenile parkinsonism (AR-JP). On initial screening of Japanese patients with AR-JP, we had found that approximately half of the parkin mutations are deletions occurring between exons 2 and 5, forming a deletion hot spot. In this study, we investigated the deletion breakpoints of the parkin mutations in 22 families with AR-JP and examined the possible association between these deletion events and meiotic recombinations. We identified 18 deletion breakpoints at the DNA nucleotide sequence level. Almost all these deletions were different, indicating that the deletion hot spot was generated by recurrent but independent events. We found no association between the deletions and specific DNA elements. Recent copy number variation (CNV) data from various ethnic groups showed that the deletion hot spot is overlapped by a highly polymorphic CNV region, indicating that the recurrent deletion mutation or CNV is observable worldwide. By comparing Marshfield and deCODE linkage maps, we found that the parkin deletion hot spot may be associated with a meiotic recombination hot spot, although such association was not found on comparison with recent high-resolution genetic maps generated from the International HapMap project. Here, we discuss the possible mechanisms for deletion hot spot formation and its effects on human genomes.     

Impairment in a negative regulatory system for TCR signaling in CD4+ T cells from old mice

To examine the involvement of lipid rafts in an age-associated decline in T cell function, we analyzed the effect of aging on the constituents of lipid rafts in resting mouse CD4(+) T cells. We found a pronounced, age-dependent reduction in PAG/Cbp, which is involved in the regulation of Src family kinases (SFKs) by recruiting Csk (a negative regulator of SFKs) to lipid rafts. This reduction is specific for T cells and is attributed, at least in part, to the reduction in its mRNA level. The reduction of PAG accompanies marked impairment in recruiting Csk to lipid rafts and a concomitant decrease in the inactive forms of SFKs. These findings indicate that old mouse CD4(+) T cells have a defect in a negative SFK regulatory system.     

O3 Tolerance and the Ascorbate-Dependent H2O2 Decomposing System in Chloroplasts

The relationship between O₃ tolerance and the chloroplast H₂O₂scavenging system (PS I     

Fate of GFP-expressing Escherichia coli in the midgut and response to ingestion in a tick, Ornithodoros moubata (Acari: Argasidae)

Ticks are well-known vectors of various pathogens but migration of the pathogens in the tick midgut is not fully understood. In the present study, the fate of microbes in the midgut of Ornithodoros moubata was observed using green fluorescent protein (GFP)-expressing Escherichia coli. Fluctuations in the percentage of hemocytes in the hemolymph (Hc) and expression of an antimicrobial peptide, defensin, in the midgut was also investigated. Most E. coli gradually disappeared in the midgut after ingestion fluctuations in Hc coincided with the changes. Expression of defensin was also confirmed and slightly up-regulated after E. coli ingestion. Moreover, it was demonstrated that E. coli can not pass through the tick midgut epithelium after ingestion by the hemolymph cultures. It is known that various pathogens and host immunoglobulins ingested with a blood meal can enter into the hemocoel, which suggests the presence of unique and complex passage mechanisms for each molecule and organism. The results obtained here help to clarify that digestion enzymes is an important function of the tick midgut to protect against invading molecules and organisms.     

Conformational change of bovine serum albumin by heat treatment

The thermal denaturation of bovine serum albumin (BSA) was studied at pH 2.8 and 7.0 in the range of 2–65°C. The relative proportions of -helix, -structure, and disordered structure in the protein conformation were determined as a function of temperature, by the curve-fitting method of circular dichroism spectra. With the rise of temperature at pH 7.0, the proportion of -helix decreased above 30°C and those of -structure and disordered structure increased in the same temperature range. The structural change was reversible in the temperature range below 45°C. However, the structural change was partially reversible upon cooling to room temperature subsequent to heating at 65°C. On the other hand, the structural change of BSA at pH 2.3 was completely reversible in the temperature range of 2–65°C, probably because the interactions between domains and between subdomains might disappear due to the acid expansion. The secondary structure of disulfide bridges-cleaved BSA remained unchanged during the heat treatment up to 65°C at pH 2.8 and 7.0.     

Synthèse Facile de Pyrazines Disubstituées en 2 et 31)

Corynebacterium equi IFO 3730 was found to oxidize a wide variety of sec-alcohols, including alkanols, substituted alkanols, alkenols and cyclic alcohols, in moderate to high yields. Among them, the sec-alcohols which have longer carbon chains were oxidized more smoothly than those with smaller numbers of carbon. Although both enantiomers of unsymmetrically disubstituted carbinols were oxidized, the S form of 2-dodecanol was converted to the corresponding ketone a little faster than the other enantiomer.     

ds-erythro-2-amino-3,4-dihydroxybutanoic acid,a constituent in the edible mushroom,lyophyllum ulmarium

An unusual amino acid occurring in the fruiting bodies of Lyophyllum ulmarium was identified as d_s-erythro- 2-amino-3,4-dihydroxybutanoic acid, which is a compound found for the first time in biological materials.