Preliminary results of the systematic screening of 4306 compounds as Red-tide toxicants.

84 p.This report presents the results of preliminary screening tests which evaluated 4,306 chemical materials as control agents for the red-tide organism, Gymnodinium breve.http://gbic.tamug.edu/request.ht

Phosphoglucomutase polymorphism in brown shrimp, Penaeus aztecus.

p. 1405-1407.Eight phenotypes of phosphoglucomutase (PGM) were detected in abdominal muscle extracts from P. aztecus by starch-gel electophoresis. The observed Phenotypes were assumed to be under the control of 5 allelic genes. This assumption was supported by the observed distribution of phenotypes. There were no significant differences in PGM phenotype distribution between sexes or among samples of shrimp taken from Galveston Bay, Texas, and Vermillion and Barataria Bays, Louisiana, USA.http://gbic.tamug.edu/request.ht

Growth of crustose lichens : a review

Crustose species are the slowest growing of all lichens. Their slow growth and longevity, especially of the yellow-green Rhizocarpon group, has made them important for surface-exposure dating (lichenometry). This review considers various aspects of the growth of crustose lichens revealed by direct measurement including: 1) early growth and development; 2) radial growth rates (RGR, mm yr−1); 3) the growth rate–size curve; and 4) the influence of environmental factors. Many crustose species comprise discrete areolae that contain the algal partner growing on the surface of a non-lichenized fungal hypothallus. Recent data suggest that 'primary' areolae may develop from free-living algal cells on the substratum while 'secondary' areolae develop from zoospores produced within the thallus. In more extreme environments, the RGR of crustose species may be exceptionally slow but considerably faster rates of growth have been recorded under more favourable conditions. The growth curves of crustose lichens with a marginal hypothallus may differ from the 'asymptotic' type of curve recorded in foliose and placodioid species; the latter are characterized by a phase of increasing RGR to a maximum and may be followed by a phase of decreasing growth. The decline in RGR in larger thalli may be attributable to a reduction in the efficiency of translocation of carbohydrate to the thallus margin or to an increased allocation of carbon to support mature 'reproductive' areolae. Crustose species have a low RGR accompanied by a low demand for nutrients and an increased allocation of carbon for stress resistance; therefore enabling colonization of more extreme environments