Localized insertion of new S-layer during growth of Bacillus stearothermophilus strains

Bacillus stearothermophilus strains PV 72 and ATCC 12980 carry a crystalline surface layer (S-layer) with hexagonal (p6) and oblique (p2) symmetry, respectively. Sites of insertions of new subunits into the regular lattice during cell growth have been determined by the indirect fluorescent antibody technique and the protein A/colloidal gold technique.During S-layer growth on both bacillus strains the following common features were noted: 1. shedding of intact S-layer or turnover of individual subunits was not seen; 2. new S-layer was deposited in helically-arranged bands over the cylindrical surface of the cell at a pitch angle related to the orientation of the lattice vectors of the crystalline array; 3. little or no S-layer was inserted into pre-existing S-layer at the poles, and 4. septal regions and, subsequently, newly formed cell poles were covered with new S-layer protein.     

Antigenic determinants distinctive of Methanospirillum hungatei and Methanogenium cariaci identified by monoclonal antibodies

Monoclonal antibodies were prepared against two species of Methanomicrobiaceae. Antibody 1A is specific for Methanospirillum hungatei strain JF1 and the determinant it recognizes is expressed on the surface of JF1 cells, where it is exposed and accessible to antibody. The determinant is found in a polypeptide (MW<12,000) in the sheath that covers the bacterial cell; it is not present in Methanospirillum hungatei strain GP1; and it is not expressed on the surface of whole cells of the other 24 methanogenic bacteria tested. It is therefore a marker of strain JF1, consequently, antibody 1A is potentially useful for tracking JF1 and fragments thereof in a variety of samples. Antibody 7A is specific for Methanogenium cariaci JR1c. It did not react with any other methanogen tested, not even with Mg. marisnigri or Ms. hungatei JF1, although these cross-react with Mg. cariaci if tested with polyclonal antisera. Therefore antibody 7A recognizes specifically a marker of Mg. cariaci JR1c.Abbreviations SIA slide immunoenzymatic assay - SDS-PAGE sodium dodecylsulfate polyacrylamide gel electrophoresis     

PARTICULATE ORGANIC MATTER AS AN ALTERNATIVE NUTRIENT SOURCE FOR TROPICAL SARGASSUM SPECIES (FUCALES, PHAEOPHYCEAE)

Large Fucales are abundant on coastal coral reefs of the Great Barrier Reef, but are often limited by the availability of inorganic nutrients. Particle loads in these reef waters are high, which is generally perceived as detrimental for aquatic plants due to a reduction of light. Here, I provide evidence that several abundant Sargassum species supplement their nutrient supply with nutrients derived from the layer of particulate matter (PM) deposited on their thalli. In experiments involving removal or addition of PM, growth rates of Sargassum spp. were up to 180% higher when particles were present on the thalli. Tissue nitrogen and phosphorus levels of thalli with a surface PM layer were 10%–30% higher than those of thalli without PM. The amount of PM deposited in situ on thalli of five species of brown algae ranged from 0.6 to 0.9 g C_org·g⁻¹ dry weight alga, depending on the species' morphology. I suggest that a nutrient-rich diffusive boundary layer is created on the thallus surface by an epiphytic microbial community that remineralizes the particulate nutrients. When algal growth is nutrient limited, the use of particle-derived nutrients as a source alternative to nutrients in the water column may outweigh any potential adverse effects of the thallus particle layer.     

Production of Polyclonal Antibodies against the Tegument of Sparganum (Plerocercoid of Spirometra mansoni) and Its Immunolocalization

In a previous study, the author developed a method for separation of the tegument of spargana (plerocercoids of Spirometra mansoni) from the parenchyme using urea. The present study, as a next step, was performed to evaluate which molecules are present in the outer tegument. Two major proteins, 180 and 200 kDa, are present in the tegument and we could make polyclonal antibodies against these molecules. Their immunolocalization was processed and the outermost layer of the spargana showed strong positive staining. Conclusively, we could confirm that the 180 and 200 kDa molecules might be tightly bound membrane proteins in the tegument of spargana.     

OBSERVATIONS ON A CHAMAESIPHONACEOIS ALGA (CYANOPHYCEAE) WITH SPECIAL REFERENCE TO EXOCYTE FORMATION1,2

A unicellular cyanophycean culture contaminant had features of both Geitleribactron Kom. and Cyanophanon Geitl. The cells were elongated, sheathless, mostly similar in diameter throughout their length, and attached polarly in rosettes or groups and produced only a single elongated exocyte (=exospore). Young cells were moderately elongated and resembled Geitleribactron. As cells aged, they greatly elongated and then resembled Cyanophanon. Some cells formed Y-shaped bifurcations, features of C. mirabile Geitl. and C. minus Geitl., but they lacked the basal sheath (pseudovagina) of C. mirabile. During exocyte formation, a thick and localized L-II wall layer protuberance extended the exocyte away from the parent cell. This terminal wall thickening then appeared to move to one side from subsequent and unequal cell wall growth. Cells sovnetimes bent abruptly, occasionally opposite a thickening in the L-II wall layer. Further studies in culture of putative Geitleribactron and Cyanophanon isolates are necessary to ascertain the breadth of their structural diversity and the identity of the present taxon.     

A morphological study on regulation of hyaline bleb formation in early embryonic cells of Cynops pyrrhogaster

Summary Presumptive ectodermal cells isolated from the animal pole region of Cynops pyrrhogaster embryos showed active formation of hyaline blebs after the eleventh cleavage. The role of the submembranous cortical layer (SCL) in hyaline bleb formation was investigated in relation to the number of cleavages. Rhodamine-phalloidin staining and transmission electron-microscopy showed structural changes in the SCL after the eleventh cleavage. Partial breakdown of the SCL by electric pulses and deformation of the SCL by treatment with cycloheximide and nocodazole induced hyaline bleb formation before the eleventh cleavage. These results suggest that the SCL plays an important role in hyaline bleb formation after the eleventh cleavage.