In situ ATR-IR spectroscopic and electron microscopic analyses of settlement secretions of Undaria pinnatifida kelp spores.

Knowledge about the settlement of marine organisms on substrates is important for the development of environmentally benign new methods for control of marine biofouling. The adhesion to substrates by spores of Undaria pinnatifida, a kelp species that is invasive to several countries, was studied by scanning electron and transmission electron microscopies (SEM/TEM) as well as by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. The IR spectra showed that adhesive secretion began approximately 15 min after initial settlement and that the adhesive bulk material contained protein and anionic polysaccharides. Energy dispersive X-ray microanalysis of the adhesive identified sulphur and phosphorus as well as calcium and magnesium ions, which facilitate the gelation of the anionic polysaccharides in the sea water. The adhesive may be secreted from Golgi bodies in the spore, which were imaged by TEM of spore thin sections. Additionally, an in situ settlement study on TiO(2) particle film by ATR-IR spectroscopy revealed the presence of phosphorylated moieties directly binding the substrate. The presence of anionic groups dominating the adhesive suggests that inhibition of spore adhesion will be favoured by negatively charged surfaces.

The Incidence and Morphology of Subcuticular Bacteria in the Echinoderm Fauna of New Zealand.

New Zealand echinoderms (33 species drawn from all five extant classes) were examined for the presence of symbiotic bacteria by fluorescence and electron microscopy. Gram-negative, subcuticular bacteria (SCB) were found in 17 species from four classes. The SCB could be classified into two major morphological types. Some species had both types of SCB. The distribution of SCB was not obviously linked to host ecology but did appear to be related to host phylogeny. Related species usually all have SCB or all lack them. The number of SCB in five species was estimated to be between 8.41 x 108 and 4.96 x 109 g-1 ash-free dry weight of host tissue. Significant differences in bacterial load and relative proportions of the different types of bacteria were found among three congeneric echinoids (Pseudechinus huttoni, P. albocinctus and P. novaezealandia). Ophiocoma bollonsi was peculiar in having groups of bacteria enclosed in host cells (bacteriocytes) within the connective tissue of the tube feet.

Embryogenesis and Larval Development of the Asteroid Patiriella regularis Viewed by Light and Scanning Electron Microscopy.

The sea star Patiriella regularis (Verrill, 1867) has indirect development through bipinnaria and brachiolaria larvae. Development of this species is typical of asteroids with planktotrophic larvae and takes 9-10 weeks. The embryos develop through a wrinkled blastula and hatch as early gastrulae. In contrast to most asteroids, a third enterocoel forms on the left side of the stomach of the bipinnaria. This structure gives rise to the left posterior coelom; its significance is discussed. We suggest that this coelom is homologous to the trunk coelom in enteropneust embryology. The surface features of the larvae were examined by scanning electron microscopy. Newly hatched gastrulae are covered by cilia, and the bipinnaria have bands of cilia that follow the contours of the larval processes. A previously undescribed plug-like structure positioned on the post-oral surface appears to function as a seal for the mouth. Brachiolaria larvae have three brachiolar arms and a centrally located adhesive disc. Each arm is covered by adhesive papillae. Raised epithelial cells that dot the surface of the papillae and adhesive disc may be batteries of secretory cells. The brachiolar arms have an extracellular coat that may serve as a protective cover for the adhesive surfaces. Competent brachiolaria swim along the substratum and exhibit searching behavior with flexure of the median brachium. They settle on the undersides of natural shell substrata and do not respond to a primary algal film. Shade appears to be an important factor in settlement and metamorphosis in P. regularis. Metamorphosis takes 5-6 days, and the post-larvae take up a free existence at a diameter of 450-500 {mu}m. The indirect development of P. regularis contrasts with the lecithotrophic and viviparous modes of development of other Patiriella species and provides the comparative basis to determine the ontogenic changes involved with evolution of direct development in the genus. The use of the divergent life histories of Patiriella as a model system for the study of evolutionary change in development is discussed.

Synthesis and antiherpes virus activity of phosphate and phosphonate derivatives of 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine.

A series of phosphate esters of 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG, 1) were synthesized and evaluated for antiherpes virus activity. The cyclic phosphate esters were made by a new, efficient method utilizing stannic chloride as a solubilizing agent. Monophosphate 2 and bisphosphate 4 showed comparable activity to DHPG and probably acted as prodrugs of DHPG. On the other hand, the cyclic phosphate of DHPG 3 was taken up by cells and bypassed the virus-specified thymidine kinase. As a result, 3 was active against DHPG-resistant HSV mutants that lacked the viral-specified thymidine kinase and was more toxic than DHPG to uninfected cells. The phosphonate 5, the least toxic of the derivatives tested, was only marginally active against HSV but showed substantial activity against human cytomegalovirus in vitro.

DESCRIPTIONS OF THE LARVAE OF STICHASTER AUSTRALIS (VERRILL) AND COSCINASTERIAS CALAMARIA (GRAY) (ECHINODERMATA: ASTEROIDEA) FROM NEW ZEALAND, OBTAINED FROM LABORATORY CULTURE.

1. Methods for the laboratory rearing of larvae of the starfishes Stichaster australis and Coscinasterias calamaria are described. 2. Larval development in S. australis and C. calamaria is very similar, although C. calamaria has a slightly faster rate of development. Fertilized eggs develop through a bipinnaria to a brachiolaria stage. Late brachiolaria larvae were present 38 days after fertilization in S. australis and 27 days after fertilization in C. calamaria. 3. As in the development of the feeding larvae, the process of metamorphosis is very similar in S. australis and C. calamaria. The time from attachment to the substratum by the late brachiolaria larvae to the completion of metamorphosis of the juvenile starfish is 6-7 days in S. australis and 6 days in C. calamaria. 4. Unfavorable culture conditions may have been the cause of abnormal larvae found in some cultures. 5. Larval development of S. australis and C. calamaria resembles closely that of other starfish species with indirect development, especially Asterias rubens. This may reflect the close taxonomic affinities of these three species.