Cloning and antigenic expression of two genes from Chlamydia psittaci avian strain

Abstract: Genes from Chlamydia psittaci P-1041 were cloned into the Bam HI site of pUC19 and were transformed to host Escherichia coli JM109. Two recombinant plasmids that expressed protein antigens of Chlamydia were isolated. The sizes of the DNA fragments were 1350 and 1710 bp, and encoded for polypeptides of M _r 25 and 42 kilodaltons (kDa), respectively. The 25-kDa protein had cross-reactivity with antisera to ten C. psittaci strains and two C. trachomatis strains, whereas the 42-kDa protein reacted only with homologous antiserum to the C. psittaci P-1041 strain. Furthermore, in Southern hybridization analysis these two fragments as probes hybridized with DNA of ten C. psittaci strains and four C. trachomatis strains. These results indicated that the two fragments shared a DNA sequence common to the chlamydial genus.     

Nitrile hydratase from a thermophilic Bacillus smithii

A novel thermophilic Bacillus smithii strain SC-J05-1, isolated from a hot spring, had the ability of hydrating nitrile to form amide. The nitrile hydratase was purified to homogeneity from the microbial cells of SC-J05-1 and was characterized. The enzyme was a 130-kDa protein composed of two different subunits (25.3 kDa and 26.8 kDa) and contained cobalt ions. This enzyme had the optimal temperature of 40°C and was stable up to 50°C. The optimal pH was in the alkaline region higher than pH 10. Received 02 September 1997/ Accepted in revised form 06 February 1998     

Sequential polymerization of flagellin A and flagellin B into Caulobacter flagella

The mode of polymerization of two species of flagellins, flagellin A and flagellin B, in polar flagella of Caulobacter crescentus was examined. By immunological staining we found that 1 to 1.2 μm of the portion of the flagellar filament proximal to the cell was composed of flagellin B, whereas about 5 μm of the distal portion was composed of flagellin A. This result, together with the previous observation that a flagellin B-less mutant cannot form normal flagella but instead forms stubs in spite of their high level of flagellin A synthesis, indicates that flagellin B is very important for the formation of complete flagella and/or for the initiation of filament formation from the hook.     

Dystrophin in rod spherules; submembranous dense regions facing bipolar cell processes

 It is known that the retina contains the protein dystrophin in the ribbon synapse, but the ultrastructural analysis is not yet fully elucidated. Our previous study reported that dystrophin is localized under the rod cell membranes in rat retinas. In the present study, we have investigated the relationship between dystrophin-rich regions of rod cell membranes and other neuronal processes in mouse retinas with a monoclonal antibody raised against the human dystrophin C-terminus. Immunoblotting, immunofluorescence stainings, and immunoelectron microscopy were employed. Immunoblotting analysis indicated that mouse retinas possessed some of the dystrophin isoforms of approximately 260 kDa, 140 kDa, and 70 kDa molecular weight. Confocal images showed a punctate appearance in the outer plexiform layer, as previously described. Immunoelectron microscopy showed that dystrophin immunoreactive products were always observed at submembranous dense regions of the rod spherule abutting bipolar processes. These results suggest that retinal dystrophin may be closely involved in signal transmission from rods to bipolar cells. Accepted: 7 May 1997     

Discontinuous DBH–height relationship of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> on Yakushima Island: effect of frequent typhoons on the maximum height

The mountain zone of Yakushima Island is covered with a mixed conifer-broadleaved forest dominated by old-growth Cryptomeria japonica (L.f.) D. Don trees. Even though Yakushima Island has been frequently struck by typhoons with wind velocities exceeding 55 m s⁻¹, the Cr. japonica trees in the mountain zone have survived for thousands of years without fatal damage. To evaluate the effect of storms on tree growth, the relationships between the stem diameter at breast height (DBH) and the heights of Cr. japonica and coexistent tree species were investigated. Two models based on an expanded allometric equation and a discontinuous piecewise allometric equation, respectively, to represent DBH–height relationships were evaluated. In all plots, the DBH–height relationship of Cr. japonica was discontinuous between small DBH and large DBH individuals. The tops of the large DBH individuals of Cr. japonica were lost to strong winds. However in each instance, they occupied the highest position in the canopy, even if they had lost their tops. In contrast, the DBH–height relationships of subcanopy broadleaved species were continuous in many plots and the equilibrium heights of the dominant broadleaved species were similar and almost in the same order regardless of the canopy heights of Cr. japonica. These results revealed a constant vertical structure in the Cr. japonica forest on Yakushima Island. Our results demonstrate a vertical niche segregation in the forest under high wind pressures and such vertical structure enables effective use of forest space and increases the basal area density.     

A simple and efficient synthesis of puromycin, 2,2′-anhydro-pyrimidine nucleosides,cytidines and 2′,3′-anhydroadenosine from 3′,5′-O-sulfinyl Xylo-nucleosides

Synthesis of antibiotics, puromycin and 3 ′-amino-3 ′-deoxy-N ⁶,N ⁶-dimethyladenosine 11 was achieved by utilizing the cyclic sulfite 6a of the xylo-3 ′,5 ′-dihydroxy group as a new protective group. The key synthetic step is the deprotection of the sulfite moiety through the intramolecular cyclization of 2-α-carbamate 7. In a similar manner, 2,2 ′-anhydro-pyrimidine nucleosides 15, ribo-cytidines 17 and 2 ′,3 ′-anhydroadenosine 14 were prepared in high yields from the corresponding sulfites 4, 5, and 6b, respectively.     

Inhibition of chromosome repair by caffeine or isonicotinic acid hydrazide on chromosome damage induced by mitomycin C in human lymphocytes

The frequency of interchromatic exchanges induced by mitomycin C in cultured human lymphocytes was markedly lowered in the presence of caffeine or isonicotinic acid hydrazide (INH) during a post-treatment period. The autoradiographic experiment showed that the decrease in the exchange frequency did not result from delaying or cell-killing effects by the post-treatment with caffeine or INH. Therefore, it may deduced that the exchange formation closely related to a process sensitive to caffeine or INH.