A Rapid Genetic Assay for the Identification of the Most Common Pocillopora damicornis Genetic Lineages on the Great Barrier Reef

Pocillopora damicornis (Linnaeus, 1758; Scleractinia, Pocilloporidae) has recently been found to comprise at least five distinct genetic lineages in Eastern Australia, some of which likely represent cryptic species. Due to similar and plastic gross morphology of these lineages, field identification is often difficult. Here we present a quick, cost effective genetic assay as well as three novel microsatellite markers that distinguish the two most common lineages found on the Great Barrier Reef. The assay is based on PCR amplification of two regions within the mitochondrial putative control region, which show consistent and easily identifiable fragment size differences for the two genetic lineages after Alu1 restriction enzyme digestion of the amplicons.     

Copulatory Courtship in Drosophila birchii and D. serrata,Species Recognition and Sexual Selection

Two endemic Australian Drosophila species, D. birchii and D. serrata, have a copulatory courtship, i.e., the males court the female mainly during copulation. In the present study we found the males of both species to mount their prospective mating partners selectively, exhibiting both sex and species recognition. The males began to sing after mounting the female, and they often exhibited also postcopulatory displays typical to copulatory courtship. D. birchii and D. serrata females discriminated against males which did not sing during mounting/copulation, which suggests that the females utilize cryptic female choice. Our findings raise the question of how widespread a phenomenon cryptic female choice is in Drosophila species.     

Cerebral blood flow velocity and cranial fluid volume decrease during +Gz acceleration

Cerebral blood flow (CBF) velocity and cranial fluid volume, which is defined as the total volume of intra- and extracranial fluid, were measured using transcranial Doppler ultrasonography and rheoencephalography, respectively, in humans during graded increase of +Gz acceleration (onset rate: 0.1 G/s) without straining maneuvers. Gz acceleration was terminated when subjects' vision decreased to an angle of less than or equal to 60 degrees, which was defined as the physiological end point. In five subjects, mean CBF velocity decreased 48% from a baseline value of 59.4 +/- 11.2 cm/s to 31.0 +/- 5.6 cm/s (p<0.01) with initial loss of peripheral vision at 5.7 +/- 0.9 Gz. On the other hand, systolic CBF velocity did not change significantly during increasing +Gz acceleration. Cranial impedance, which is proportional to loss of cranial fluid volume, increased by 2.0 +/- 0.8% above the baseline value at the physiological end point (p<0.05). Both the decrease of CBF velocity and the increase of cranial impedance correlated significantly with Gz. These results suggest that +Gz acceleration without straining maneuvers decreases CBF velocity to half normal and probably causes a caudal fluid shift from both intra- and extracranial tissues.     

REEVALUATION OF THE NITROGEN FIXATION BEHAVIOR IN THE MARINE NON‐HETEROCYSTOUS CYANOBACTERIUM LYNGBYA MAJUSCULA1

Lyngbya majuscula Harvey ex Gomont is a common marine cyanobacterium in tropical and subtropical near‐shore waters. A few reports have indicated that L. majuscula fixes nitrogen only in the light. Because this feature is uncommon among non‐heterocystous cyanobacteria, we attempted a reevaluation. Nitrogenase activity, regulation, and localization were examined over diel cycles on natural populations of L. majuscula growing in subtidal zones off Zanzibar in the western Indian Ocean. The data show that L. majuscula fixed nitrogen and synthesized nitrogenase in all cells during the dark phase of a diel cycle. During the light phase, nitrogenase was degraded to undetectable levels.     

Lipid Composition of Bacillus cereus During Growth and Sporulation

The lipid composition of Bacillus cereus during growth and sporulation was examined. The total lipid extract accounted for 2 to 3% of the dry weight of the cells and consisted of neutral lipids (30 to 40%) and phospholipids (60 to 70%). Phospholipids were separated by thin-layer chromatography into eight components; phosphatidyl ethanolamine, phosphatidyl glycerol, and diphosphatidyl glycerol were the major phospholipids and accounted for over 90% of the total. Also identified was a diglycosyl diglyceride and an alanine ester of phosphatidyl glycerol. Diphosphatidyl glycerol was more difficult to extract than the other components in vegetative and stationary-phase cells, but became increasingly easy to extract during spore maturation, and during sporulation cellular levels increased. Phosphatidyl glycerol had a high turnover rate; it accounted for about 70% of the phospholipid synthesis throughout sporulation but only represented between 30 and 40% of the total phospholipid at any time. Phosphatidyl ethanolamine, on the other hand, accounted for about 20% of the synthesis but was the major phospholipid (50 to 60% of the total).     

Long‐term effects of climate change on carbon flows through benthic secondary production in small lakes

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Peroxyvanadium compounds inhibit glucose-6-phosphatase activity and glucagon-stimulated hepatic glucose output in the rat in vivo.

The present investigation was undertaken to characterize the direct inhibitory action of the peroxyvanadium compounds oxodiperoxo(1, 10-phenanthroline) vanadate(V) (bpV(phen)) and oxodiperoxo(pyridine-2-carboxylate) vanadate(V) (bpV(pic)) on pig microsomal glucose-6-phosphatase (G-6-Pase) activity and on glucagon stimulated hyperglycemia in vivo. Both bpV(phen) and bpV(pic) were found to be potent competitive inhibitors of G-6-Pase with Ki values of 0.96 and 0.42 microM (intact microsomes) and 0.50 and 0.21 microM (detergent-disrupted microsomes). The corresponding values for ortho-vanadate were 20.3 and 20.0 microM. Administration of bpV(phen) to postprandial rats did not affect the basal glucose level although a modest and dose-dependent increase in plasma lactate levels was seen. Injection of glucagon raised the plasma glucose level from 5.5 mM to about 7.5 mM in control animals and this increase could be prevented dose-dependently by bpV(phen). The inhibition of the glucagon-mediated blood glucose increase was accompanied by a dose-dependent increase in plasma lactate levels from 2 mM to about 11 mM. In conclusion, the finding that vanadate and bpV compounds are potent inhibitors of G-6-Pase suggests that the blood-glucose-lowering effect of these compounds which is seen in diabetic animals may be partly explained by a direct effect on this enzyme rather than, as presently thought, being the result of inhibition of phosphoprotein tyrosine phosphatases and thereby insulin receptor dephosphorylation.