Thermal history of reef-associated environments during a record cold-air outbreak event

Summary Several polar continental air masses intruding into the south Florida/northern Bahama Bank region during January 1981 caused record low air temperatures and rapid chilling of extensive shallow-water carbonate systems. Numerous coral kills along the Florida reef tract and massive fish mortalities in Florida Bay were attributable to unusually cold waters generated at this time. Thermal evolution of Florida Bay/Florida reef tract and northern Bahama Bank waters from 8 to 21 January was assessed from thermal infrared data acquired by the NOAA-6 environmental satellite, in situ water temperatures, local meteorological data, and a computerized heat flux model. Field observations and laboratory experiments identify 16°C as a thermal stress threshold for most reef corals (Mayor 1915; Davis 1981). Temperaturecorrected digital satellite data indicated that water temperatures below 16°C were generated in Florida Bay and on Little and Great Bahama Banks during a 10-day period in January. Lowest temperatures on the Florida reef tract resulted from offshelf transport of Florida Bay water through major tidal channels. Offshelf movement of bay water is driven primarily by strong northerly winds, density gradients, and tidal pumping. Absence of reef development opposite major tidal passes along the Florida reef tract (Ginsburg and Shinn 1964) and aperiodic coral kills along bank margins can be attributed to this process, which has probably had a limiting influence on Holocene reef development in these areas.     

The accumulation and intracellular compartmentation of cadmium,lead, zinc and calcium in two earthworm species (Dendrobaena rubida and Lumbricus rubellus) living in highly contaminated soil

Summary The earthworm Lumbricus rubellus contained more Ca and Zn, and less Pb and Cd, than Dendrobaena rubida living in the same contaminated disused-mine soil. Differences in the kinetics of Ca turnover may account for some of the inter-specific differences in heavy metal burdens, although the calciferous glands do not seem to be directly involved in heavy metal excretion. A comparison of the present findings with published data indicated that the concentration of soil Ca and the bioavailability of heavy metals, both factors being allied to soil pH, are important exogenous determinants of heavy metal accumulation by different earthworm populations. Electron microprobe X-ray analysis of air-dried smears of chloragogenous tissue showed that the metals were fairly specifically compartmentalized into two distinct organelles in both worms: Ca, Pb and Zn were found (associated with P) in the chloragosomes; Cd was found (with S and probably in stoichiometric association) in a more electron-lucent vesicular component, designated the cadmosome, but which may be identical with the debris vesicles which are characteristic inclusions in conventionally-fixed chloragocytes. The in vivo incorporation of Pb by the chloragosomes of D. rubida was accompanied by the loss of Ca, Zn and P.     

The spatial organization of the hierarchical proliferative cells of the crypts of the small intestine into clusters of 'synchronized' cells

Abstract. A statistical analysis of the distribution of [³H]TdR-labelled cells in longitudinal and transverse sections of crypts from the ileum of the mouse, indicated that there was a strong tendency for labelled or unlabelled cells to be associated in short vertical runs and lateral clumps, suggesting the presence of clusters of labelled cells on the sides of the crypts. A model is discussed for the cellular spatial organization of the crypt that proposes a vertical alignment of the cells within branches of the proliferative cell lineage. The model would predict vertical alignment of partially synchronized cells as well as some lateral clumping.
In the present studies mitoses were not observed at higher levels in the crypt than labelled (S phase) cells. This observation would be predicted by the non-random spatial organization suggested by the model.
The model would also make certain predictions concerning cell migration. These are discussed in relation to cell migration studies which include evidence that migration continues in the absence of mitotic activity.     

Primary cultures and the levels of cytochromeP450 in hepatocytes from mouse,rat, hamster,and rabbit liver

Summary Hepatocyte primary cultures (HPC) derived from rat, mouse, hamster, and rabbit liver were characterized for a variety of parameters. The conditions that maximized recovery, attachment, and survival varied between species. Hepatocytes from all four species were capable of attaching in serum-free Williams’ medium E (WME), but optimal attachment as monolayer cultures was achieved for mouse and hamster HPC in medium receiving 1% calf serum supplementation. Hamster hepatocytes required additional cations, whereas rabbit and rat hepatocytes displayed maximal attachment in medium supplemented with 10% calf serum. Survival of mouse and rabbit hepatocytes after 24 h in serum supplemented media was in the order of 90%. Rat and hamster hepatocyte 24 h survival was approximately 70 and 60%, respectively, and was not significantly affected by serum supplementation. Hepatocytes from each species varied in their content of cytochromeP450 at the time of isolation and in the rate of reduction during culture. Mouse and rat hepatocytes demonstrated the most rapid decline in content during the initial 24 h in culture, whereas concentrations in rabbit hepatocytes were virtually unchanged. The rate of decline inP450 concentrations in hamster hepatocytes was intermediate between those displayed by rat and rabbit hepatocytes. These studies have delineated conditions useful for the culture of hepatocytes from four species and have documented the status of an important parameter of their functional capability. This study was supported by EPA contract 68-01-6179. C. J. Maslansky was a recipient of a Monsanto Fund Fellowship in Toxicology.     

Feeding behavior and prey ofNeoscona arabesca [Araneae: Araneidae] andTetragnatha laboriosa [Aranea: Tetragnathidae] in soybean fields

During observations in soybean fields, 136Neoscona arabesca (Walckenaer) and 46Tetragnatha laboriosa Hentz were collected with prey. Significantly different prey compositions were recorded, withN. arabesca utilizing a large number ofColeoptera whileT. laboriosa captured primarilyHemiptera-Homoptera. Neoscona arabesca was observed to feed primarily in the evening following web construction, whileT. laboriosa fed predominantly in the morning. Although both of these species captured relatively large numbers of homopterans, most of their prey were species which are not considered to be pests in soybean.

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Résumé Lors d'observations dans des champs de soja, 136Neoscona arabesca (Walckenauer) et 46Tetragnatha laboriosa Hentz furent recueillies avec leurs proies. Des différences significatives furent notées dans la composition des différents groupes de proies,N. arabesca capturant un grand nombre de Coléoptères tandis queT. laboriosa capture en premier lieu des Hémiptères (Hemiptera-Homoptera). Il fut observé queNeoscona arabesca se nourrit surtout dans la soirée qui suit la construction de la toile, alors queT. laboriosa se nourrit le plus souvent le matin. Bien que ces deux espèces aient capturé un nombre relativement important d'homoptères, la plupart de leurs proies étaient des espèces qui ne sont pas considérées comme nuisibles au soja.

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This paper (82-7-20) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director.     

Experimental control of the Mormon cricket,Anabrus simplex,byNosema locustae [Microspora: Microsporida], a protozoan parasite of grasshoppers [Ort.: Acrididae]

Spores ofNosema locustae Canning were applied with aerial equipment for experimental control of the Mormon cricket,Anabrus simplex Haldeman. The application resulted in infections in crickets during the season of application and the season following application. Spores were observed in cricket feces which indicated probable vertical transmission between generations. Reduced densities of crickets during the second season suggested effective control byN. locustae.