The structure ofHLA-B35 suggests that it is derived fromHLA-Bw58 by two genetic mechanisms

The primary structure ofHLA-B51 andHLA-Bw52 suggested thatHLA-B51 was derived fromHLA-Bw52 by the combination of a genetic exchange withHLA-B8 and a point mutation. To investigate the evolution of theHLA-B5 cross reactive group, theHLA-B35 gene was cloned and the primary structure was determined.HLA-B35 is identical toHLA-Bw58 except in the α₁ domain. The α₁ domain ofHLA-B35 except Bw4/Bw6-associated amino acids is identical to that ofHLA-B51 ^*, which was suspected to be an intermediate gene betweenHLA-B51 andHLA-Bw52. These data suggest thatHLA-B35 has evolved fromHLA-Bw58 in two steps; an in vivo replacement of the α₁ domain withHLA-B51 and genetic exchange with one of theHLA-Bw6 genes. These three genes andHLA-Bw58 are postulated to share a common ancestor.     

Stress fibers in the mesenteric mesothelial cells of the large intestine of the bullfrog,Rana catesbeiana

Summary Actin-containing cytoplasmic fibers were visualized in the mesenteric mesothelial cells of the large intestine of bullfrog tadpoles by rhodamine-phalloidin staining of en face preparations of mesothelial cells. These fibers were concurrently stained by immunofluorescence using antibodies to myosin or -actinin. Electron microscopy showed the presence of bundles of microfilaments in the basal cytoplasm of the cells. Such fibers in the mesothelial cells may be comparable to the stress fibers present in cultured cells. The mesothelial cells initially formed axially oriented stress fibers when they changed from a rhombic to a slender spindle-like shape. On the other hand, stress fibers disappeared as cells transformed from elongated to polygonal shapes during the period of metamorphic climax. Expression of stress fibers in these cells appears to be related to the degree of tension loaded on the mesentery, which may be generated by mesenteric winding. These stress fibers in the mesothelial cells may serve to regulate cellular transformation. They may also help to maintain cellular integrity by strengthening the cellular attachment to subepithelial tissue against tensile stress exerted on the mesentery.     

Location of nuclear antigen(s) recognized by DSB389 MAb, a monoclonal antibody against desmin, observed by confocal laser scanning fluorescence microscopy

The location of antigen(s) of DSB389 MAb, a monoclonal antibody which was raised against an intermediate filament protein, desmin, was investigated in HeLa S3 cells by indirect immuno-electron microscopy and by confocal laser scanning fluorescence microscopy. At interphase, the antigen(s) locates mainly in the intra-nuclear space adjacent to chromatin and sometimes near the nuclear periphery. At mitosis, they locate at the periphery of the chromosomes -first at each chromosome, then around the mass of chromosomes. The antigen(s) are thought to be a component of one type of nuclear matrix which is present outside both chromatin and chromosomes and which has some structural role(s) in organizing them in the nucleus or in the nuclear region.     

Comparative Study of Glial Marker Proteins in the Hypoplastic Cerebellum of Jaundiced Gunn Rats

The behavior of marker proteins of glial cells [alpha-enolase, beta-S100 protein, and glial fibrillary acidic protein (GFAP)] was investigated quantitatively by using enzyme immunoassay systems during the development of cerebellar hypoplasia in jaundiced Gunn rats. A neuronal marker protein, gamma-enolase, was also measured as a reference. At postnatal day 8 corresponding to the early stage of cerebellar damage, the amount of beta-S100 on a protein basis was significantly higher in jaundiced homozygotes (jj) than in control nonjaundiced heterozygotes (j+), whereas no differences in alpha- and gamma-enolases and GFAP were observed between the two groups of rats. At days 15 and 30, which correspond, respectively, to the advanced and late stages of cerebellar damage, the three glial proteins, especially GFAP, were higher and the neuronal protein was lower in the jj rat cerebellum than in the control. These results are consistent with the reported histological observations that neuronal cells are vulnerable and damaged by bilirubin, whereas glial cells seem to be less sensitive. On the other hand, the amounts of beta-S100 and alpha-enolase per cerebellum were significantly lower in jj rats at days 15 and 30, as in the case of gamma-enolase, whereas that of GFAP remained at the same level as the control at day 15 and showed a slight but significant decrease at day 30. The possibility is suggested that beta-S100 and GFAP may be available as biochemical indicators of glial cells, especially in the early and advanced stages of cerebellar damage, respectively, but that alpha-enolase is less available.     

ent-Kaurene Synthesis and Endogenous Levels of Gibberellins in a Shoot Forming Tobacco Crown Gall Tissue

The in vitro ent-Mcaurene synthesizing capacity, as well asthe endogenous GA content of shoot-forming tobacco crown gallsinduced by a nopaline-type Ti plasmid, was studied. For determinationof the ent-kaurene synthesizing capacity, an HPLC procedurepreceded by sample clean-up was used and the GA content wasexamined by GC-SIM. Kaurene synthesis reached a maximum at thebeginning of the logarithmic phase of growth. There was a clearcorrelation between the ent-kaurene synthesizing capacity andthe content of C₂₀-GAs. It seems that gibberellin synthesisis related to growth and development of the tissue. The natureof the GAs identified suggests, that the GA metabolism mightbe an unusual one. (Received October 12, 1987; Accepted April 11, 1988)     

Induction of Cytoplasmic Streaming and Movement of Chloroplast Induced by L-Histidine and its Derivatives in Leaves of Egeria densa

Rotational cytoplasmic streaming in leaves of Egeria densa wasinduced by light as well as by L-histidine (L-His). During bothtreatement with light and with L-His chloroplasts on the periclinalface were dislodged and moved to the anticlinal face where rotationalcytoplasmic streaming occurred. The effective concentrationof L-His was about 0.01 mM and the effect was almost saturatedat 0.1 mM. A derivative of L-His, 3-methyl-L-histidine, wasslightly less effective than L-His. By contrast, 1-methyl-L-histidinewas almost ineffective for induction of streaming, not onlyin Egeria but also in Vallisneria. Our resutlts are in markedcontrast to Fitting's result (1936) that 1-M-L-His is more effectivethan L-His. In Egeria, 1-methyl-L-His counteracted the stimulativeeffect of L-His. 1-Methyl-L-His penetrated into leaf cells ofEgeria to the same extent as 3-methyl-L-His and to a greaterextent than L-His. This observation excludes the possibilitythat the impermeability of leaves to 1-M-L-His might be responsiblefor its ineffectiveness. 1-M-L-His did not interfere with photodinesis.Differences in the mechanism of induction of rotational streamingby L-His and by light are discussed. ⁴ Present address: Fukui Institute of Technology, Gakuen, Fukui,910 Japan (Received July 16, 1990; Accepted December 20, 1990)     

Superinfection with R Factors by Transduction in Escherichia coli and Salmonella typhimurium

Superinfection immunity is found in the conjugal transfer of R factors between two fi(+) R factors and between two fi(-) R factors (fi = fertility inhibition), as we reported previously. In contrast, no reduction in the frequencies of transduction of an fi(+) R factor 222 was caused by the presence of fi(+) R factors in the recipients in transduction systems with phage P1kc in Escherichia coli K-12 and with phage P22 in Salmonella typhimurium LT-2. The absence of superinfection immunity in transduction may be due to the difference in the route of entry of the R factor. The frequencies of transduction of an fi(+) R factor were reduced, although slightly, by the presence of fi(-) R factors in the recipients. This reduction is probably due to host-controlled restriction of the entering fi(+) R factor by the fi(-) R factors in the recipients, since transduction of an fi(+) R factor by the transducing phage propagated on the strain carrying both fi(+) and fi(-) R factors was not reduced by the presence of homologous fi(-) R factors in the recipients. The fi(+) R factor 222, when transduced to the recipient strains carrying other R factors, recombined genetically at high frequencies with these resident R factors, regardless of their fi type.     

Redescription of Vorticella oceanica Zacharias, 1906 (Ciliophora: Peritrichia) with notes on its host, the marine planktonic diatom Chaetoceros coarctatum Lauder,1864

The late-spring quantitative relationship between epiphyton and macroinvertebrates was analyzed on the basis of units of colonizable plant surface of Typha angustifolia, Phragmites australis and Nuphar lutea (floating leaves) in the shallow euthrophic Lake Loosdrecht (the Netherlands), with a high seston load. The non-predatory chironomid larvae (Glyptotendipes viridis, Endochironomus albipennis, Pentapedilum sordens, Cricotopus sylvestris agg.) dominated among the macroinvertebrate taxa, controlling the diversity and resemblance of macroinvertebrate assemblages. There was a gradient in functional feeding groups among the chironomids from continuous filtering of the seston to prevailing utilization of epiphyton. We found no direct relationship between the total macroinvertebrate abundance and the epiphyton mass on the plants surface. We attribute this to the filter feeding-strategy of the most abundant species, Glyptotendipes viridis, that utilizes seston in the eutrophicated lake.