acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

The molt stages of the fiddler crab, Uca pugilator, are described with setal development and extent of epidermal retraction in pleopods as the major criteria for molt stage determination. Setogenic molt staging is a simple technique to use and produces no apparent adverse physiological effects. A single crab can be staged throughout an entire molt cycle using this technique. Setogenic molt staging may be performed using setae from several regions of the body. The molt cycle in Uca was divided into the following stages and substages: A-B, C, D(,0), D(,1), D(,2), and D(,3-4) The enzyme, B-glucosidase, was demonstrated to exist in the fiddler crab and was characterized by kinetic, temperature, pH sensitivity and reaction rate data. Levels of enzyme activity in the cuticle and epidermis were also determined in relation to the stages of the molt cycle. The V(,0) pH sensitivity data indicate an optimum pH of approximately 5.0. Temperature sensitivity data indicate an optimum temperature of approximately 80(DEGREES) C. The apparent Km and Vmax values of the crab B-glucosidase are 15.57mM PNPG and 0.0712mM PNPG/min respectively. The pH sensitivity and rate data suggest a multiplicity of forms for the exhibited enzyme activity. The temporal relationship of B-glucosidase activity with known molt cycle events suggests this enzyme is involved with protein sclerotization in the fiddler crab / acase@tulane.edu

Exposure of Gulf killifish (Fundulus grandis) to a sublethal water soluble fraction of South Louisiana Crude oil or to one of its components (naphthalene or 2,6-dimethylnaphthalene) results in various physiological changes. During a 24-hr exposure period, these toxic aromatic hydrocarbons cause a decrease in opercular breathing rate, dispersion of the pigment in the melanophores and a decrease in the mean dopamine level in fish brains. Ultraviolet spectrophotometric assays of water and tissue indicate bioconcentration and localization of the naphthalene compounds in the prosencephalon and myelencephalon after 24 hr of exposure. Pharmacological studies indicate that at least one of the naphthalene compounds' sites of toxic action is the storage granules containing dopamine. Speculations are presented concerning brain dopamine levels and breathing and color change mechanisms in teleosts. Mean levels of 5-hydroxytryptamine, dopamine and norepinephrine in the brains of Gulf killifish are reported / acase@tulane.edu

The present investigation was undertaken to examine some aspects of ovarian maturation and its regulation by the neuroendocrine system of the fiddler crab, Uca pugilator. In vivo studies in which extracts of thoracic ganglia were injected into intact and eyestalkless females, revealed the presence of OSH in Uca. Furthermore, OSH showed seasonal activity with regard to the annual reproductive cycle Studies of the effect of OSH, OIH and cyclic AMP on protein synthesis in the ovary were conducted in vitro by an organ culture method. Eyestalk tissue and cAMP decreased radioactive leucine incorporation into newly synthesized protein in previtellogenic ovaries but had no effect on protein synthesis in maturing ovaries. The thoracic ganglion inhibited protein synthesis in both previtellogenic ovaries and maturing ovaries A critical examination was made of the role of the ovary in the synthesis of yolk protein, vitellin. Maturing ovaries incorporated radioactive leucine into newly synthesized vitellin in vitro. Two subunits of vitellin were isolated by SDS-polyacrylamide gel electrophoresis. Their molecular weights are 77,700D and 87,700D The electrophoretic profiles of hemolymph from crabs in various stages of ovarian development were determined under denaturing conditions. Two female-specific polypeptides were observed in the hemolymph of crabs undergoing vitellogenesis and those having mature ovaries. Neither one was present in males or females with previtellogenic ovaries. It appears then that females of Uca pugilator undergo both intraovarian and extraovarian yolk protein synthesis / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

Chronic administration of Angiotensin II (Ang II) at low dose leads to progressive increases in arterial pressure and intrarenal accumulation of Ang II, which occurs by increased Ang II synthesis and Ang II receptor subtype 1 (AT1) mediated endocytosis. Since the internalized Ang II may have a functional role interacting with intracellular sites including nuclear Ang II binding sites reported in liver, adrenal cortex, cerebellum and smooth muscle but not in kidneys, the aims of this study were to determine if chronic infusion of Ang II changes the AT receptor densities in the rat renal cortex and if kidney cells have specific nuclear Ang II binding sites which densities may be altered by chronic administration of Ang II. Sprague Dawley rats were infused with Ang II at 70 ng/min via osmotic minipumps for 13 days and the tail cuff systolic blood pressures increased from 112 +/- 5 to 179 +/- 2 mmHg while the body weight gains decreased from 5.86 +/- 0.13 to 4.67 +/- 0.17 g/day, respectively, in control sham infused and Ang II infused rats (n = 17 and 13). On day 14, the kidneys were harvested and the renal cortexes homogenized to obtain crude membrane (CM), plasma membrane (PM) and nuclear fractions (NF) by differential centrifugation. A homologous competition assay between 125I-Sar1-Ile 8-AngII and Sar1-Leu8-AngII for binding sites in CM was used to determine the inhibitory concentration 50% (IC 50), Hill slopes, AT receptor affinities (Kd) and densities (Bmax). In addition, the total AT and AT1 binding densities in PM and NF were measured with a single point assay and alkaline phosphatase activity was used to determine purity/contamination of the fractions. The results indicated that; (a) the chronic infusion with Ang II did not alter the affinities or densities of its own receptors in the rat renal cortex, (b) AT 1 was the prevalent Ang II receptor subtype in the renal cortex, (c) AT 1 'like' binding sites were present in the nuclei of renal cells and (d) chronic administration of Ang II 'in vivo' did not alter Ang II binding sites in the nuclear fraction of the renal cortex / acase@tulane.edu

acase@tulane.edu