Microscopic investigation of three species of Diophrys (Ciliophora,Euplotida, Uronychiidae) from Japan,including Diophrys peculiaris nov. spec

Three species of Diophrys, D. peculiaris nov. spec., D. cf. scutum and D. oligothrix, isolated from the New Nagasaki Fishing Port, Nagasaki, Japan, were investigated using live observation and protargol impregnation. Diophrys peculiaris nov. spec. can be recognized by having two characteristic clusters of rod-like structures and two groups of dikinetids located on anterior dorsal portion of cell. Morphogenetic data show that this part of the life cycle basically proceeds as in congeners, except for the formation of dikinetids under the rod-like structures. In the opisthe, the origin of dikinetids under the rod-like structures is still unknown, but the old dikinetids under the rod-like structures may be retained by the proter. The Japanese population of Diophrys cf. scutum resembles other populations of D. scutum well except for moniliform macronuclear segments. Our populations of D. oligothrix correspond well with other populations in terms of general morphology and ciliary pattern, in particular the continuous dorsal kineties with loosely arranged cilia.     

Nutritional interaction in an alga-barnacle association

Nitrogen is the major growth-limiting nutrient for marine algae. One potential source of nitrogen for marine algae is ammonium released by invertebrates. Many mid-intertidal reefs in northeastern New Zealand are dominated by a close association between the honeycomb barnacle Chamaesipho columna and an encusting brown alga Pseudolithoderma sp. Growth of Pseudolithoderma was enhanced in the presence of live C. columna, which released ammonium at a greater rate than the maximum rate of ammonium uptake by Pseudolithoderma. Algal tissue on barnacle tests had a lower C:N ratio than tissue located more than 2 cm from the nearest barnacle, suggesting the barnacle is an important source of nitrogen for the alga. The role of nutrient exchange in determining ecological patterns of species in marine communities is discussed.     

DNA extraction for 16S rRNA gene analysis to determine genetic diversity in deep sediment communities

A protocol was devised which permitted the extraction of DNA from deep marine sediments up to 503 m below the sea floor. These sediments have been laid down over the last 3 million years. 16S rRNA gene sequences were amplified from the DNA by the polymerase chain reaction. The details of the successful extraction and polymerase chain reaction methodology varied between samples from different depths. This emphasizes the attention to detail required to allow the diversity of bacteria in these deep sediments to be studied.     

Antibiotic production by the marine photosynthetic bacterium Chromatium purpuratum NKPB 031704: localization of activity to the chromatophores

Abstract Over 200 strains of marine purple photosynthetic bacteria were isolated. Two strains showed antibiotic activity towards Saccharomyces cerevisiae and were tentatively identified as Chromatium purpuratum . Crude antibiotic, prepared by solvent extraction, showed a broad antimicrobial spectrum. The highest activity was found in the chromatophore fraction. Chromatographic separation of purified light harvesting complex from one strain, NKPB 031704, showed the presence of two separate pigmented compounds which were responsible for antimicrobial activity. Our findings reveal the unexpected ability of photosynthetic bacteria to produce broad spectrum antibiotics. In addition, this is the first example of intracellular localization of antibiotic activity in a marine bacterium.     

The potential of production of sulfated polysaccharides from Porphyridium

Summary The environmental conditions prevailing in Israel make marine algae an attractive crop for the production of valuable chemicals. A marine species of Porphyridium seems to fit this purpose.The unicellular red alga Porphyridium is encapsulated by a polysaccharide envelope that is present in the gel state. This polysaccharide is an acidic heteropolymer composed of sulfated sugars. It forms ionic bridges through divalent cations, thus reaching a very high molecular weight. The thickness of the polysaccharide capsule varies according to the phase of growth and the growth conditions. Its outer part dissolves in the growth medium, which becomes progressively more viscous. Sulfated polysaccharides form theramlly reversible gels similar to agar and carrageenan, which are usually extracted from marine macroalgae. These gels have been finding increasing use in commercial applications as gelling agents, thickeners, stabilizers, and emulsifiers.We have done experiments on the cultivation of a marine species of Porphyridium for the production of polysaccharides. This unicellular alga has an advantage over the macroalgae due to its relatively faster growth rate and the possibility to regulate its growth. The potential for production of the polysaccharide, both that dissolved in the external medium and that attached to the cell (including an intracellular fraction), and the effects of growth conditions on productivity were suudied in the laboratory. Porphyridium was also cultivated outdoors in seawater in 1-m² ponds and its growth potential investigated.