Fine Structure of the Schizont Stage of the Testate Marine Ameba,Trichosphaerium sp.*

SYNOPSIS. The schizont stage of 3 strains of the testate marine ameba, Trichosphaerium sp., was examined in the transmission electron microscope. The cytoplasm of this multinucleate organism contained the usual organelles; the test was covered by spicules. Pseudopodial types included broad ectoplasmic lobopods that assisted in locomotion, and thin dactylopods that probably had a sensory function. Nuclear division, observed in one of the strains, was characterized by an intact nuclear envelope (at least through anaphase), and the absence of centrioles. Nuclei in an ameba divided synchronously. An unusual intranuclear body of unknown function was found in another of the strains examined.     

Phagotrophic Ingestion of a Blue-Green Alga by Ochromonas*†

Anacystis nidulans disappeared rapidly from culture in the presence of an unidentified species of Ochromonas. Disappearance was light-independent and could be induced neither by bacteria associated with, nor by soluble products released from the flagellate. Electronmicrographs of mixed cultures revealed numerous A. nidulans cells in various stages of digestion within vacuoles of Ochromonas. Evidently the disappearance of the alga from culture resulted from phagotrophy by the chrysomonad. A 2-stage digestive process is suggested whereby A. nidulans cells are initially sequestered in the posterior “leucosin” vacuole and then undergo the terminal stages of digestion and elimination in smaller, peripheral vacuoles.     

Fine Structure of Poly-β-Hydroxybutyric Acid Granules in a Blue-Green Alga, Chlorogloea fritschii

Granules characterized as poly-beta-hydroxybutyric acid are described in Chlorogloea fritschii, a blue-green alga. They are generally spherical inclusions of slight electron density which are limited by a membrane approximately 3 nm in thickness.     

Marine Amebae From Clean and Stressed Bottom Sediments of the Atlantic Ocean and Gulf of Mexico*,†,‡

SYNOPSIS Amebae isolated from sediments of the Atlantic Ocean and Gulf of Mexico were maintained in continuous culture and most were identified to genus and species. Twenty-six species representing 12 genera were recognized from existing literature and several others (Flabellula, Mastigamoeba, Cochliopododium) were identified only to genus. One ameboflagellate and several small limax-type amebae which require further study also were isolated. Other sarcodmids belonging to the Heliozoida, Testocida, Leptomyxida, and Proteomyxida were identified only tentatively. the distribution of the amebae and ameba-like organisms was tabulated for the following geographic areas: Atlantic Ocean near Long Island, New York: Atlantic Ocean 16-65 miles offshore from New York and New Jersey: Atlantic Ocean 1-50 miles offshore from Maryland and Delaware: and the Gulf of Mexico 3.5-41 miles offshore from the southeastern United States. Amebae present in shellfish holding trays at Lewis. Delaware, were isolated, and identified to compare the distribution of species in laboratory tanks with those present in natural ocean bottoms. Published accounts of each collection site were reviewed to obtain specific data on contamination with sewage wastes, acid wastes, dredge spoils, and petroleum hydrocarbons. Two previously undescribed amebae were found to represent new genera and species and are described herein, one from the Delaware mariculture facility, and the other from the digestive tract of the blue crab, Callinectes sapidus, and the gill surface of the lady crab, Ovalipes ocellatus. Sarcodinids present in clean or stressed environments were listed, and genera and species that were widespread or apparently geographically restricted were recorded.     

黄海繁茂膜海绵中微生物多样性的研究

构建了中国黄海繁茂膜海绵中细菌16S rDNA克隆,对其遗传多样性进行了分析,发现海绵中相关细菌16S rDNA基因主要归类于紫硫细菌门(Proteobacteria)中的α-亚门、γ-亚门,和放线菌门(Actinobacteria)等类群。所获得的16S rDNA序列与GenBank中的已知序列差异较大,反映出该海绵存在尚未发现的微生物新信息。     

Fine Structure of Human Malaria In Vitro*†

SYNOPSIS. The erythrocytic cycle of the human malaria parasite, Plasmodium falciparum, was examined by electron microscopy. Three strains of parasites maintained in continuous culture in human erythrocytes were compared with in vivo infections in Aotus monkeys. The ultrastructure of P. falciparum is not altered by continuous cultivation in vitro. mitochondria contain DNA-like filaments and some cristae at all stages of the erythrocytic life cycle. The Golgi apparatus is prominent at the schizont stage and may be involved in the formation of rhoptries. In culture, knob-like protrusions first appear on the surface of trophozoite-infected erythrocytes. The time of appearance of knobs on cells in vitro correlates with the life cycle stage of parasites which are sequestered from the peripheral circulation in vivo. Knob material of older parasites coalesces and forms extensions from the erythrocyte surface. Some of this material is sloughed from the host cell surface. The parasitophorous vacuole membrane breaks down in erythrocytes containing mature merozoites both in vitro and in vivo. Merozoite structure is similar to that of P. knowlesi. The immature gametocytes in culture have no knobs.     

Torsional Movements in the Ameba,Chaos carolinensis,Suggest a Helical Cytoskeletal Organization*†

SYNOPSIS. Centrifugation for 30–40 seconds at 8,000 g has been used to render monopodial specimens of the large free-living ameba. Chaos carolinensis. These monopodial amebae exhibit obvious torsional movements in the tail. In many cases the posterior ectoplasm assumes the form of a screw with helical ridges forming in place of the more common straight dorsal fins. This finding prompted a re-examination of normal polypodial C. carolinensis, and a majority of these were found also to exhibit torsional movement in the tail and in retracting pseudopodia. These movements suggest that the cytoskeleton of Chaos may have a helical component in its organization.     

The Fine Structure of the Gregarine Pyxinoides balani Parasitic in the Barnacle Balanus tintinnabulum*†

SYNOPSIS. The fine structure of the eugregarine Pyxinoides balani was studied and compared with that of other gregarines previously examined with the electron microscope. P. balani contains cell organelles comparable to those in the archigregarine Selenidium hollandei. These include mitochondria, Golgi complexes, granular and agranular endoplasmic reticulum, membrane-limited granules, vacuoles and myonemes. A comparison of the distribution and fine structure of these organelles with those of the above archigregarine was made. The possible function of the Golgi complex in assisting in producing the transverse septum is suggested. The surface of P. balani is composed of a surface-membrane complex different from that of S. hollandei, and similar to those of the eugregarines previously studied. The complex is composed of an outer plasmalemma, subjacent pentalaminar layer, and underlying, homogeneous, electron-dense layer. The pentalaminar layer is 140–170 Å thick and has a structure reminiscent of fused cell membranes seen in tight junctions, myelin figures and nerve myelin. The pentalaminar layer is derived from subsurface cisternae found in sporozoites. The underlying, homogeneous, electron-dense layer is 450–500 Å thick. Pores and caveolae are found as specializations of the pentalaminar and homogeneous electron-dense layers. Endoplasmic reticulum is closely associated with the caveolae. The location of the pentalaminar layer at the surface and the presence of pores and caveolae in its structure suggests some transport and/or segregation function.     

Isolation of a Strain of Chlamydomonas reinhardi with Altered Control of Glyceraldehyde 3-Phosphate Dehydrogenase*, †

SYNOPSIS. A strain of Chlamydomonas reinhardi is described in which the control of glyceraldehyde 3-P dehydrogenase is altered; the activity of the NADP-dependent enzyme is apparently independent of chlorophyll content.     

Distribution of Acantharia in the Western Sargasso Sea in Correspondence with “Thermal Fronts”1

A study of plankton samples collected in the Western Sargasso Sea during nine cruises has shown discontinuity between samples from different latitudes as regards their percentage, abundance, and number of species of Acantharia. Limits separating zones rich in Acantharia from those poor in Acantharia were singled out. The latitude at which the difference in abundance occurs can vary. This is in accord with differences in primary production, phytoplankton, and mesopelagic fishes noted by other workers who believe that the points of these faunal changes correspond to a temperature change indicated as “thermal fronts.”     

Effect of Bacteria Associated with the Green Alga Ulva reticulata on Marine Micro- and Macrofouling

The green alga Ulva reticulata (Forsskal) is often free from biofouling in Hong Kong waters. An early study indicated that bioactive substances from this alga inhibit settlement of the polychaete Hydroides elegans (Haswell). It is also predicted that epibiotic bacteria protect this alga from micro- and macrofouling. In this study, bacterial strains from the surface of U. reticulata were isolated and their inhibitive activities on micro- and macrofouling assayed. The strains were identified by 16S rRNA analysis as belonging to the genera Alteromonas , Pseudoalteromonas and Vibrio . There was no significant effect of these strains or their extracts (aqueous and ethanol) on the growth of five Vibrio strains isolated from natural biofilm. Two bacterial strains ( Alteromonas sp. and Vibrio sp. 3) were non-toxic to the benthic diatom Nitzschia paleacea (Grunow) while the other five strains caused a low level of mortality. No one bacterial strain was toxic to the larvae of H. elegans . Aqueous extract of one of the isolated bacterial species, i.e. Vibrio sp. 2, significantly ( p <0.00001) inhibited the settlement and metamorphosis of H. elegans larvae. The putative antifouling compounds have a molecular weight of >100 kD. On the other hand, biofilm of Pseudoalteromonas sp. 2 and aqueous extract of Vibrio sp. 2 suppressed the settlement of larvae induced by 3-isobutyl-1-methylxanthine (IBMX). Other epibiotic bacteria and their extracts had neither inhibitive nor inductive effects on larval settlement of H. elegans . The results indicate that the antifouling mechanism of U. reticulata may be dependent not only on materials from the macroalga itself but also on the epibiotic bacteria on the algal surface.     

Diversity of Antibiotic-Active Bacteria Associated with the Brown Alga Laminaria saccharina from the Baltic Sea

Bacteria associated with the marine macroalga Laminaria saccharina, collected from the Kiel Fjord (Baltic Sea, Germany), were isolated and tested for antimicrobial activity. From a total of 210 isolates, 103 strains inhibited the growth of at least one microorganism from the test panel including Gram-negative and Gram-positive bacteria as well as a yeast. Most common profiles were the inhibition of Bacillus subtilis only (30%), B. subtilis and Staphylococcus lentus (25%), and B. subtilis, S. lentus, and Candida albicans (11%). In summary, the antibiotic-active isolates covered 15 different activity patterns suggesting various modes of action. On the basis of 16S rRNA gene sequence similarities >99%, 45 phylotypes were defined, which were classified into 21 genera belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Phylogenetic analysis of 16S rRNA gene sequences revealed that four isolates possibly represent novel species or even genera. In conclusion, L. saccharina represents a promising source for the isolation of new bacterial taxa and antimicrobially active bacteria.     

Characterization of a Corrinoid Compound in the Edible (Blue-Green) Alga,Suizenji-nori

The edible blue-green alga (cyanobacterium), Suizenji-nori, contained 143.8±22.4 μg of vitamin B₁₂ per 100 g dry weight of the alga (mean±SE, n=4). A corrinoid compound was purified from the dried Suizenji-nori, and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified corrinoid compound were not identical to those of true vitamin B₁₂, but to those of pseudovitamin B₁₂ which is inactive for humans.     

Changes in the Classification of Several Major Taxa of Ciliophora on the Basis of a Numerical Phenetic Analysis*,†

SYNOPSIS. Several taxonomic problems arising from recent revisions of the phylum Ciliophora. Initially, electro- and light-microscopic features of 7 species from 4 genera of colpodid ciliates were analyzed by several numerical phenetic procedures. The phenogram derived by using Jaccard's coefficient as the measure of similarity and the unweighted pair-group arithmetic clustering method (UPGMA) yielded a classification with the highest cophenetic correlation coefficient. Subsequently, relationships among 22 oligohymenophoran and related genera were determined by analyzing 57 ultrastructural and light-microscopic features with Jaccard's coefficient and UPGMA. On the basis of these results, the suborder Peniculina is elevated to ordinal rank and the family Turaniellidae is transferred from the Peniculida to the Tetrahymenina. The phenogram also indicated that the nassuline ciliates may be allied with the OLIGOHYMENOPHORA rather than the KINETOFRAGMINOPHORA.     

The Cell Surface of Trypanosoma musculi Bloodstream Forms. I. Fine Structure and Cytochemistry*†

SYNOPSIS. An extracellular surface coat was observed at the fine-structural level on the outer lamina of the pellicular and flagellar membranes of intact Trypanosoma musculi bloodstream forms. The surface coat had a mean width of 9.2 nm, and was composed of a somewhat electron dense, uneven, fibrillar-like matrix. Brief trypsin treatment of living blood forms completely removed the cell surface coat. Several cytochemical methods applicable to electron microscopy were used to detect the presence and distribution of carbohydrates in the trypanosome's surface coat and pellicular membrane. The polycationic dye compounds employed were: ruthenium red, ruthenium violet, Alcian blue chloride, and lanthanum nitrate. Electron-dense stain reaction products, indicative of polysaccharides, were evident in the surface coat of cells treated with these dyes, which also agglutinated both living and glutaraldehyde fixed cells. Like the surface coat, the pellicular membrane of trypsinized cells gave strong positive staining reactions with the several dyes, indicating the presence of membrane bounded carbohydrates, and living and glutaraldehyde-fixed trypsinized cells were agglutinated with the polycationic stains. Bloodstream forms were treated with the enzymes, α-amylase, dextranase, and neuraminidase. No obvious morphologic difference, however, was apparent between the surface coat of untreated cells and those subjected to treatment with any of the various glycoside hydrolase enzymes. Further, these enzymes had no apparent gross effect on the staining affinity of the surface coat for the several polycationic dyes. Cationized ferritin was used to visualize the negative cell surface charge of T. musculi bloodstream forms. Large quantities of cationized ferritin were bound in the surface coat matrix. Glycoside hydrolase enzyme treatments had no apparent effect on the amount of ferritin bound in the surface coat. Cationized ferritin was bound also to the outer lamina of the pellicular membrane in trypsinized cells, which had quantitatively less ferritin bound per surface unit area than bloodstream forms untreated by the enzyme. Living and glutaraldehyde-fixed cells were agglutinated with cationized ferritin. The results obtained in the various experiments indicated that polyanionic polysaccharides were constituent terminal ligands of the surface coat matrix and pellicular membrane in T. musculi bloodstream forms.     

Structure and Life Cycle of Trypanoplasma beckeri sp. n. (Kinetoplastida), a Parasite of the Cabezon,Scorpaenichthys marmoratus,in Oregon Coastal Waters*,†

SYNOPSIS. Structure of Trypanoplasma beckeri sp. n. from the cabezon, Scorpaenichthys marmoratus (Ayres), is described from living specimens and from both Giemsa-, and protargol-stained smears. Flagellates from fish blood were usually long and slender, averaging 109.0 × 6.5 fan. The anterior flagellum averaged 8.5 μm; the recurrent flagellum bordered the body and terminated as a very short free flagellum, 2.5 μm long on the average. No true undulating membrane was observed, but in living individuals the recurrent flagellum undulated rapidly near its point of origin. The oval nucleus, averaging 8.5 × 4.0 μm, was located near the anterior cad of the body. An argentophilic, aciculum-like structure appeared to connect the nucleus to the area at the base of the flagella. The kinetoplast was not observed in fish blood forms. On the basis of laboratory experiments, the leech, Malmiana diminuta Burreson, was ascertained to be the vector for T. beckeri. Upon entry into the leech, flagellates became rounded, and division commenced within a few hours. Division continued for ?48 h and the flagellates became progressively smaller until reaching a length of ?10.0 μm. After 72 h they were found in high numbers in the proboscis sheath and also in the anterior crop of the leech. When infected leeches fed on an uninfected fish, flagellates were first observed in the fishes’ peripheral circulation 8 days later.     

Variation in the Fine Structure of a Marine Achromobacter and a Marine Pseudomonad Grown Under Selected Nutritional and Temperature Regimes

Certain features of the fine structure of a marine achromobacter and a marine pseudomonad were dependent upon the conditions of growth. Cells of achromobacter grown at 10 C in a low peptone-seawater (SW) medium displayed the characteristic morphology of the achromobacter: a regularly undulant outer element of the cell wall and a planar inner element, tightly packed ribonucleoprotein (RNP) particles in the cytoplasm, deoxyribonucleic acid (DNA) disposed in a lobate manner, and dense inclusion bodies. Few mesosomes, however, were seen. Cells of achromobacter grown at 10 C in a high peptone-SW medium had larger and more highly organized mesosomes. At 22 C, in a low peptone-SW medium, no mesosomes were seen, but the inclusions were more frequently seen and were larger in the achromobacter cells. At 22 C, in a high peptone-SW medium, these cells revealed the greatest variation in cellular morphology. They contained both small and large mesosomes, or no mesosomes, and both small and large inclusions, or no inclusions. Pseudomonad cells at 10 C in a low peptone-SW medium revealed a typical gram-negative morphology: double-layered, irregularly undulant cell wall; more nearly planar cytoplasmic membrane; densely stained, lightly packed RNP particles; finely fibrillar, axially disposed DNA; simple mesosomes. At 10 C, in a high peptone-SW medium, pseudomonad cells revealed associated strands of material and intracytoplasmic ringlike structures. At 22 C, in a low peptone-SW medium, pseudomonad cells had a more undulant cell-wall and a more nearly planar cytoplasmic membrane. At 22 C, in a high peptone-SW medium, these cells revealed prominent blebs of the cell wall.     

Considerations in Developing a Functional Approach to the Governance of Large Marine Ecosystems

Interest in the management of the environment and its resources on an ecosystem basis has been increasing, in both terrestrial and marine contexts. In recent years, the concept of the large marine ecosystem has become a point of focus at the national and international levels as a possible unit for management of ocean and coastal areas. An ecosystem approach, however, challenges the manner in which marine resources and the environment that sustains them have been managed in the past. Governance is a key element in ecosystem management and encompasses the formal and informal arrangements, institutions, and mores that determine how resources and the environment are utilized. This study explores some of the problems, concepts, and principles involved in efforts to provide needed governance arrangements if large marine ecosystem-based management is to be implemented and made effective.     

The Social Structure of Inachus phalangium,a Spider Crab Associated with the Sea Anemone

The behaviour of the spider crab Inachus phalangium (Fabricius, 1775), which lives in association with the sea anemone Anemonia sulcata (Pennant), was studied in the field. The crab was found in the littoral zone of the Mediterranean Sea near Banyuls sur Mer, France, in the whole depth range studied (0.5–25 m). The crabs had a long-lasting association with individual Anemonia sulcata, occasionally with Aiptasia mutabilis. Most crabs were found in association with the same anemone for several days, some crabs were found in association with the same anemone for longer than one month. In the areas studied, on average 65 Inachus phalangium were found on 100 anemones. Crabs released in the vicinity of anemones moved towards them and entered them. Inachus phalangium could walk between the tentacles of Anemonia sulcata and Aiptasia mutabilis without eliciting feeding reactions of the anemone. The crabs left the anemones for moulting. After moulting masking material was removed from the exuvia and used again. The animals returned into an anemone while still soft. Material used for masking, usually algae, could be picked off the body and eaten. Masking material may be a food reservoir in addition to providing camouflage. Anemones were left only during night-time. The crabs left their anemone to moult, to feed in the vicinity, fleeing from larger conspecifics, and to migrate to a different anemone. Outside the anemone's protection Inachus was eaten by several species of fish. Individuals appeared to avoid each other. 57% of all animals were found alone on an anemone. Large males and females were more frequently found alone than were small males and females. Fights were observed between members of the same and of the opposite sex. During fights, legs and claws could be torn off. Adult males migrated more often between anemones and moved over larger distances when migrating than did adult females. Adult males probably migrated in search of sexually mature females. Such a roving strategy is evolutionarily stable only when the higher costs (in terms of energy expenditure and mortality) are compensated for by a higher number of offspring than produced in the alternative, pair-bonding strategy.     

Isolation and Characterization of a Protein Associated with Carotene Globules in the Alga Dunaliella bardawil

The halotolerant alga Dunaliella bardawil accumulates very large amounts of [beta]-carotene when exposed to high light intensity. The accumulated [beta]-carotene is concentrated in small, oily globules within the chloroplast and has been suggested to protect the alga against photodamage by high irradiation (A. Ben-Amotz, A. Katz, M. Avron [1982] J Phycol 18:529-537;A. Ben-Amotz, M. Avron [1983] Plant Physiol 72: 593-597; A. Ben-Amotz, A. Shaish, M. Avron [1989] Plant Physiol 91: 1040-1043). A 38-kD protein was identified and purified from [beta]-carotene globules and was designated carotene globule protein (Cgp). Induction of Cgp occurs in parallel with [beta]-carotene accumulation in D. bardawil grown under different inductive conditions. Cgp is overproduced in a constitutive mutant strain that overproduces [beta]-carotene and is not detected in Dunaliella salina, a species that does not accumulate [beta]-carotene. Cgp production was not suppressed by norflurazon, an inhibitor of [beta]-carotene synthesis that leads to accumulation of the carotenoid precursor phytoene. Immunogold-labeling analysis by electron microscopy demonstrates that the protein is localized at the periphery of the globules. Proteolytic cleavage by trypsin enhances the coalescence and destruction of the globules, in parallel with Cgp disappearance. It is suggested that the function of Cgp is to stabilize the structure of the globules within the chloroplast.