Simulated marine respirometry of biodegradable polymers

Eleven microorganisms were isolated from several temperate marine locations in the northeast Altantic coast of the United States and one tropical location in the Pacific Ocean (Hawaii) for the purpose of developing a rapid and accurate method of screening biodegradable materials for their susceptibility to mineralization. The materials evaluated in this study included chemically modified starch, amylose and pullulan, poly(3-hydroxybutyrate-co-valerate), (PHB/V), cellulose acetate, and a modified lignin/styrene. Some of the soluble, unmodified, biologically produced substrates such as starch, pullulan, and amylose mineralized rapidly. In general, the synthetic, insoluble polymers and the chemically modified polymers, such as acetylated and chlorinated amylose and pullulan, mineralized more slowly, although the ultimate mineralization of some of the substituted polysaccharides equaled or exceeded that of the unmodified substrate. The insoluble bacterial polyester, PHB/V, degraded rapidly after a short induction period. Initial respiration rate data, in general, could not be used as a predictor of ultimate mineralization. It was found that the cumulative level of carbon dioxide evolved signifies the minimum extent of biodegradation of the substrate, and the oxygen consumed is a good indicator of the maximum extent of substrate degradation.Paper presented at the Biodegradable Materials and Packaging Conference, September 22–23, 1993, Natick, Massachusetts.     

Agricultural chemical exposure in small farmers in Guyana

A study of self-reported injury from agricultural chemical exposure was conducted in farmers in rural Guyana. One hundred and ninety agricultural workers were studied, of which 167 (88%) were male. Morbidity from agricultural chemical exposure was common, with 87 farmers (46%) reporting having experienced at least one episode of illness after agricultural chemical exposure. Relatively few of the farmers sought medical assistance for their symptoms, with only 20 farmers (11%) visiting a local doctor and only two farmers (1%) reporting going to a hospital for treatment. Local farmer use of protective equipment was limited. Pyrethroids and herbicides paraquat and glyphosate were the most commonly used agricultural chemicals in the population studied. Data showed that exposure to agricultural chemicals remains frequent, with incidence of severe injury requiring less frequent medical attention.     

Sonographic demonstration of fetal sacrococcygeal teratoma

Six cases of sonographically diagnosed fetal sacrococcygeal teratoma (SCT) are presented and illustrate the variable features of fetal SCT. The sonographic findings assisted the parents and perinatal team in making decisions, and in two of the cases the children survived after elective Cesarean section and prompt neonatal resection of the tumors. None of the patients showed signs of malignant degeneration of the teratoma or metastases. Fetal SCT no longer should be considered a uniformly fatal condition. The literature on sacrococcygeal teratoma detected after birth indicates that the mortality rate is correlated with the degree of extension of the tumor. Therefore, the classification of sonographically diagnosed fetal SCT according to its size and position is important for decisions regarding pregnancy management.     

Boating and navigation activities influence the recruitment of fish in a Baltic Sea archipelago area

We studied the effects of boating and navigation activities on the recruitment of coastal fish in the Stockholm archipelago in the NW Baltic proper. The impacts were quantified by sampling metamorphosed young-of-the-year (Y-O-Y) fish in inlets adjacent to i) routes for medium-sized passenger ferries; ii) berths (small marinas) with small boats; and iii) references. Species with high preference for vegetation were negatively influenced by boating and navigation activities and species with low preference positively influenced. Pike (Esox lucius) Y-O-Y were significantly more abundant in reference areas, while bleak (Alburnus alburnus) were more abundant in dredged marinas. No statistically significant patterns were identified for perch (Perca fluviatilis) although there was a trend of low abundance along ferry routes. Many species of nearshore fishes are dependent on submerged vegetation as spawning and larval substrate, structural refuge and feeding habitat. Our results suggest that the negative effects from boating and navigation activities on the coverage and height of vegetation, especially on species of Chara and Potamogeton spp., may contribute to changes in the Y-O-Y fish community.     

Pre-ingestive treatment of bombardier beetles by jays: food preparation by “anting” and “sand-wiping”

Summary. Evidence is presented, obtained with two species of jays, that these birds differ in the ways in which they prepare bombardier beetles for ingestion. Blue Jays subject bombardiers to “anting,” a procedure by which the beetles are induced to eject their spray into the plumage of the birds. Florida Scrub Jays, in contrast, which live in an area where the soil is sandy, subject bombardiers to “sand-wiping,” causing the beetles to eject their spray into the substrate. Both strategies lend themselves also to pre-ingestive treatment of other chemically protected arthropods. Anting is a strategy widely practiced by birds, possibly because it can be put to use no matter what the nature of the terrain. Sand-wiping, as implied by its name (which we here coin), may be of more restricted occurrence, given that it can be carried out only on loose, penetrable soil.