Behavioral responses of red hake,Urophycis chuss,to decreasing concentrations of dissolved oxygen

Synopsis Laboratory experiments were conducted to examine changes in behavior of red hake,Urophycis chuss, under decreasing concentrations of dissolved oxygen (DO). Since the ecological requirements of this species change with age, responses were measured for three different groups: (1) age 0+, = 89 mm total length (TL); (2) age 1+, = 238 mm TL; and (3) age 2–3+, = 397 mm TL. As DO decreased from 8–10 mg l^-1 to < 0.5 mg l^-1, changes were evident in active time, water column activity, range of horizontal movement, food searching, and agonistic behavior. Age 0+ fish were most sensitive, moving up into the water column and swimming continuously as DO levels fell below 4.2 mg l^-1. Age 2–3+ fish were the least responsive, remaining on the substrate and increasing only their range of movement at concentrations below 3 mg l^-1. Responses of age 1 + fish were variable, possibly reflecting a transition stage between the younger and older fish. Common to all groups was the decrease and eventual cessation of food searching.     

Sex determination from the radius in humans

The discriminatory capacity of the radius in sex determination was investigated in a Dutch skeletal collection of recent origin. Midshaft subperiosteal diameter, maximum length and maximum transverse distal width were measured from roentgenograms. The discriminatory capacity of the radius was found to be of the same order as that reported in the literature for the other long bones. Maximum transverse distal width showed the highest consistency (85%) between estimated and documented sex. This method requires only the presence of the distal fragment of the radius.     

Isolation of intact high-molecular-weight DNA by using guanidine isothiocyanate.

A method for obtaining high-molecular-weight chromosomal DNA from Bacteroides intermedius and Bacteroides gingivalis is described. This technique is a modification of the guanidine isothiocyanate isolation procedure for RNA and should be useful for isolating intact DNA from organisms with high endogenous nuclease activity.     

Pathophysiology of pH and Ca2+ in bloodstream and brain

The highlights of the literature and our work on tetany and hyperventilation are reviewed. Our studies concern the following: (1) the changes of [Ca2+] in circulating plasma caused by respiratory and "metabolic" acidosis and alkalosis; (2) critical plasma [Ca2+] levels associated with signs of tetany and neuromuscular blockade; (3) changes in cerebral [Ca2+]o caused by hypo- and hyper-calcaemia, and the changes in cerebral [Ca2+]o and pHo caused by acute systemic acidosis and alkalosis; and (4) effects of changing [Ca2+]o and pHo levels on synaptic transmission in hippocampal formation. Our main conclusions are (1) changes of plasma [Ca2+] caused by "metabolic" pH changes are greater than those associated with varying CO2 concentration; (2) acute systemic [Ca2+] changes are associated with small cerebral [Ca2+]o changes; (3) the decreases in systemic and cerebral [Ca2+]o caused by hyperventilation are too small to account for the signs and symptoms of hypocapnic tetany; (4) moderate decrease of [Ca2+]o depresses and its increase enhances synaptic transmission in hippocampal formation; and (5) H+ ions in extracellular fluid have a weak depressant effect on neuronal excitability. CO2 is a strong depressant, which is only partly explained by the acidity of its solution. CO2 concentration is a significant factor in controlling cerebral function.     

Assignment of the prealbumin (PALB) gene (familial amyloidotic polyneuropathy) to human chromosome region 18q11.2–q12.1

Summary The assignment of the human prealbumin (PALB) gene to chromosome region 18q11–q12.1 has been achieved using a human genomic probe in the study of human-mouse somatic cell hybrids and by in situ hybridization. Because familial amyloidotic polyneuropathy was reported previously to be due to a mutation in prealbumin, it can be inferred that the gene for this disorder also maps to 18q11.2–q12.1.     

In vivo cytogenetic effects of cooked food mutagens

Using a variety of in vivo cytogenetic endpoints, we have investigated the effects of several compounds formed during the cooking of meat. C57Bl/6 mice were used to test for an increase in the frequency of sister-chromatid exchanges (SCEs), chromosomal aberrations, and micronucleated erythrocytes by 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). MeIQx and DiMeIQx did not induce SCEs in mouse bone marrow cells. PhIP induced sister-chromatid exchanges, but not chromosomal aberrations in bone marrow. In peripheral blood lymphocytes, PhIP did induce aberrations at 100 mg/kg, the highest dose tested. PhIP induced a low but significantly increased frequency of micronuclei in normochromatic but not polychromatic erythrocytes in bone marrow and peripheral blood. However, dose responses were not observed. With the exception of the SCEs induced by PhIP, these results contrast with observations made in vitro, where these compounds were found to have significant genotoxicity in mammalian cells and a very high mutation frequency in prokaryotic systems.     

Increased protoplast yield from oat leaves and bean internodes by non-injurious mechanical perturbation

Summary A simple new technique has been developed to greatly increase the yield of protoplasts from plant organs without injury to the plant. Mechanical perturbation (MP) by non-stressful rubbing of oat leaf segments and bean internodes yielded ten to twenty times more viable protoplasts than did controls. The increase in protoplast yield due to MP is best manifested, if the organs are excised and transferred to the cellulytic enzymes immediately after MP is given to the intact organ. The enzymes begin digesting from the lower end of the bean internodes and proceed acropetally. Vacuum infiltration of control oat leaf segments for 15 min with enzyme solution resulted in increased yield but less than due to MP. Increased levels of calcium (10 mM) in the medium decreased the yield of protoplasts from both control and MP-treated plant organs. EGTA significantly increased the yield of protoplasts from control oat leaf segments and marginally over that found in the control bean internodes. Cycloheximide increased the yield of protoplasts from oat leaf segments but not from bean internodes. It is suggested that MP may increase the susceptibility of cell wall polymers to cellulytic enzymes by reducing calcium cross linking. MP is thus a tool for increasing the yield of protoplasts from plant organs without causing injury.Abbreviations CHI cycloheximide - EGTA ethyleneglycol-bis-(ß-aminoethyl ether)-N,N-tetraacetic acid - FDA fluorescein diacetate - MP mechanical perturbation     

The effect of pregnancy and foaling on intravaginal pressure in pony mares

Pressures were recorded monthly at two sites in the vagina of each of five pregnant and five nonpregnant pony mares; pressures in five mares were also recorded weekly after foaling. The developing pregnancy did not influence pressure, and after foaling the integrity of the seal formed by the caudal reproductive tract was rapidly restored.     

Effect of secretagogues on chromogranin A synthesis in bovine cultured chromaffin cells. Possible regulation by protein kinase C.

Chromogranin A is a major component of storage granules in many different secretory cell types. After [35S]methionine labelling of proteins from cultured bovine chromaffin cells, chromogranin A was immunoprecipitated with specific antibodies, and the radioactivity incorporated into chromogranin A was determined and used as an index of its synthesis rate. Depolarization of cells with nicotine or high K+ evoked a Ca2+-dependent increase in chromogranin A synthesis, whereas muscarine, which does not evoke significant Ca2+ influx from bovine chromaffin cells, had no effect on chromogranin A synthesis. Forskolin, an activator of adenylate cyclase, affected neither the basal nor the nicotine-stimulated rate of chromogranin A synthesis. In contrast, 12-O-tetradecanoylphorbol 13-acetate (TPA), an activator of protein kinase C, significantly enhanced the incorporation of radioactivity into chromogranin A. Sphingosine, an inhibitor of protein kinase C, abolished both nicotine-stimulated and TPA-induced chromogranin A synthesis. In addition, long-term treatment of chromaffin cells with TPA decreased protein kinase C activity and inhibited the nicotine-stimulated chromogranin A synthesis. These results suggest that protein kinase C may play an important role in the control of chromogranin A synthesis.     

The taxonomic status and distribution of Bushbabies in Malawi with emphasis on the significance of vocalizations

The debated identity of a small forest bushbaby in Malawi is resolved by a short-term field study of the animals’ behavior. Locomotor styles, calling patterns, and the structure of advertising calls confirm that the species is Galago zanzibaricusrather than G. demidoffor G. thomasi.A detailed comparison of acoustic structure between the Malawi animals and G. zanzibaricusin Kenya demonstrates a degree of between-population variation, although the calls remain conservative in those parameters expected to aid recognition of conspecifics. Distribution records extend the known geographical range of G. zanzibaricusover most of the northern half of Malawi. Further studies are required to link the animals from this region with either of the previously recognized subspecies: G. z. zanzibaricusfrom East Africa or G. z. grantifrom southern Malawi, Mozambique, and Zimbabwe.