The second polar lobe of theSabellaria cementarium embryo plays an inhibitory role in apical tuft formation

Summary The embryo ofSabellaria cementarium (Polychaeta) forms a polar lobe at each of the first two cleavage divisions which becomes absorbed into one of the blastomeres at the end of the division. Lobe removal experiments show that the polar lobe preceding first cleavage is necessary for the development of the apical tuft and the posttrochal region of the trochophore larva. The polar lobe preceding second cleavage is smaller than the first polar lobe and is necessary only for post-trochal region development. In blastomere isolation experiments, isolates containing the C but not the D blastomere form apical tufts. Isolates containing the D but not the C blastomere do not form apical tufts. When the polar lobe preceding second cleavage is removed and the C and D blastomeres are separated and raised in isolation, each can form an apical tuft. When the second cleavage is equalized with sodium dodecyl sulfate (SDS) such that both the C and the D blastomeres receive second polar lobe material, no apical tuft is formed. These results suggest that apical tuft determinants are distributed to both the C and D blastomeres at second cleavage but that the second polar lobe contains an inhibitor for apical tuft formation which is shunted to the D blastomere after the completion of second cleavage.     

The identification of dimethylphenylarsine as a microbial metabolite using a simple method of chemofocusing

Candida humicola acts on benzenearsonic acid to produce dimethylphenylarsine, which was identified by mass spectroscopy following the chemofocusing of the volatile metabolite onto a mercuric chloride impregnated filter. The same technique established that trimethylarsine is the volatile metabolic product obtained from C. humicola treated with 4-NH₂-2-OHC₆H₃AsO(OH)₂ and (CH₃)₃AsO. Arsanilic acid, 4-NH₂C₆H₄AsO(OH)₂, is not metabolized to a volatile arsine.     

Preliminary results from the self-regulatory treatment of high-medication-consumption headache

Data are presented from a prospective clinical replication series of ten consecutive high-medication headache patients who presented for nondrug treatment of their headaches. For the first eight, an attempt was made to withdraw the patients from medication, with the assistance of relaxation training, prior to entering a comprehensive self-regulatory treatment program. For the last two, drug withdrawal accompanied the treatment. Six of the ten patients showed clinically significant reductions in headache activity, which held up over follow-ups of up to 12 months. Psychological tests provide some discrimination between success and failures.This research was supported in part by a grant from NINDS, No. NS-23340. Appreciation is expressed to Dr. Kenneth A. Appelbaum and Ms. Denise Michultka for their roles in this study.     

Respiration in air and water of four mediterranean trochids

Data on the morphology and behavior of five species of spionid polychaete from muddy sand habitats in both the United Kingdom and the northwest coast of North America are presented. The data are consistent with the hypothesis that browsing predation by visual predators is important now and has been important in the evolutionary past. As predicted by such a hypothesis, regenerating individuals are common in all the populations examined. Individuals belonging to species that expose their anterior ends while feeding and/or defecating have cryptic anteriors (Pygospio elegans Claparède, Rhynchospio glutaeus (Ehlers), Malacoceros fuliginosus (Claparède), and Spiophanes bombyx (Claparède)). Individuals belonging to species that do not expose their anteriors while feeding and/or defecating do not have cryptic anteriors (Pseudopolydora kempi (Southern)). Given these data it is still unclear as to how many of the geographic patterns of coloration that have been reported for infauna are associated with the presence of visual predation. Further investigations are suggested.     

Spontaneous feline sporotrichosis: A fine structural study

Fine structural details of the parasitic yeastlike phase of Sporothrix schenckii contained in biopsy tissue from a naturally-occurring case of disseminated feline sporotrichosis are described and illustrated by electron microscopy. Both free and phagocytosed fungal cells were observed. The fungal cells were contained within an extracellular, electron transparent vacuolar area which was bounded by a limiting membrane of probable host origin. The yeastlike cells were characterized by a conspicuous layer of osmiophilic microfilaments which occurred along the outermost surface of the cell wall. In many yeastlike cells, scattered, membranebound vacuoles containing electron opaque material were observed in the cytoplasm. Asteroid bodies were not observed.     

Insulin degradation XVIII. On the regulation of glutathione-insulin transhydrogenase in the hyperglycemic obese (ob/ob) mouse

The occureence of insulin-degrading activity in the liver of the obese hyperglycemic mouse (ob/ob) and its litter mate has been studied. The trichloroacetic acid-soluble product formed from insulin upon incubation with liver homogenate was identified as the A chain of insulin. In Ouchterlony double-diffusion experiments with antibody to purified rat liver glutathione-insulin transhydrogenase, mouse liver homogenate and the microsomal fraction each gave a single precipitation band of identity with the purified rat liver enzyme. These results indicate that the insulin-degrading activity preseny in the mouse liver is, in fact, glutathione-insulin transhydrogenase. Subcellular distribution studies of glutathione-insulin transhydrogenase and marker enzymes indicate that the transhydrogenase is located primarily in the microsomal fraction of mouse liver homogenate.The ob/ob mouse, which is a genetic mutant characterized by obesity, hyper-insulinism and resistance to the hypoglycemic action of insulin, contains hepatic glutathione-insulin transhydrogenase activity (per mg microsomal protein) markedly higher (40–60%) than its lean litter mates. However, a major portion of the increased hepatic enzyme in the ob/ob mouse occurs in a latent state; the increased amount of enzyme either is unavailable or is nonfunctional, although the ob/ob mouse still contains more of the functional form than the lean mouse. Thus, the results are consistent with the suggestion that the hepatic glutathione-insulin transhydrogenase is probably under a feedback control by circulating insulin.     

Beyond ecosystem modeling: A roadmap to community cyberinfrastructure for ecological data‐model integration

In an era of rapid global change, our ability to understand and predict Earth's natural systems is lagging behind our ability to monitor and measure changes in the biosphere. Bottlenecks to informing models with observations have reduced our capacity to fully exploit the growing volume and variety of available data. Here, we take a critical look at the information infrastructure that connects ecosystem modeling and measurement efforts, and propose a roadmap to community cyberinfrastructure development that can reduce the divisions between empirical research and modeling and accelerate the pace of discovery. A new era of data‐model integration requires investment in accessible, scalable, and transparent tools that integrate the expertise of the whole community, including both modelers and empiricists. This roadmap focuses on five key opportunities for community tools: the underlying foundations of community cyberinfrastructure; data ingest; calibration of models to data; model‐data benchmarking; and data assimilation and ecological forecasting. This community‐driven approach is a key to meeting the pressing needs of science and society in the 21st century.