Cerapeplus gen.n. and the classification of micropeplids (Coleoptera: Micropeplidae)

Cerapeplus siamensis gen.n., sp.n. from Thailand is described and illustrated. The new genus is characterized by filament-based lamellar secretions arising from the lateral body margin, a feature observed for the first time in Coleoptera. Possible autapomorphies for the micropeplid genera are discussed. It is concluded that Cerapeplus and Kalissus are monophyletic; Micropeplus and/Or Peplomicrus are probably polyphyletic but both genera together form a monophyletic group. A number of characters support the family status of the micropeplids recently proposed by some authors. A revised family diagnosis is provided.     

Secretory B-cell activity in insulin dependent maturity-onset diabetic.

In 10 insulin dependent maturity onset diabetics we found elevated basal C-Peptide levels (4.78 +/- 0.5 ng/ml. Normal range 1.1--3.6 ng/ml), which could be suppressed by insulin injection to the same extent as in sulfonylurea treated diabetics could be demonstrated. C-Peptide immunoreactivity in these patients therefore seems to be newly secreted rather than accumulated material. Since adrenalectomized patients could be suppressed in the same way, it is likely, that catecholamines are not the major factor in the mechanism of suppression. Therefore only decrease of bloodsugar levels seems to be accountable for the decrease of C-Petide levels. High C-Petide levels in insulin dependent maturity onset diabetics which cannot be stimulated but suppressed may be explained by a loss of glucoreceptor molecules.     

Factors affecting the regeneration and distribution of riparian woodlands along a northern prairie river: the Red Deer River,Alberta, Canada

Abstract. Flooding patterns and variations in the composition and successional trends of riparian vegetation in the upper and lower Red Deer River in southern Alberta, Canada, were studied in order to establish which flood regimes were most important in the regeneration and maintenance of riparian vegetation communities, with a particular focus on riparian poplars. The dominant riparian tree in the upper river is Populus balsamifera with some Picea glauca and in the lower river Populus deltoides (the plains cottonwood). Dendrochronological studies of the poplars along the river show that major periods of regeneration correspond with major flood events during the record period. Extensive cottonwood regeneration occurred in the period 1900–20, corresponding with a series of floods, some as high as the 1 in 100-year event. In addition, just prior to and during this period there was a significant reduction in use of the floodplain by bison, clearance of forests and a higher incidence of fires in upper reaches of the river and a series of high rainfall years. A series of floods greater than the 1 in 10-year flood occurred in the 1950s and stimulated the most extensive regeneration of poplars experienced since the 1920s. Parts of the lower Red Deer floodplain are now at elevations well above the 1 in 100-year flood event. It is suggested that fringe replenishment of riparian poplars is currently the dominant form of regeneration and that the large stands of mature poplars found on the floodplain, initiated during the end of the last century and first decades of this century, are unlikely to be replaced unless large floods (>1 in 50-year events) occur again. Construction of the Dickson Dam above the city of Red Deer in 1983 has led to attenuation of floods and a reduced likelihood that extensive flooding and poplar regeneration will occur again. A number of recommendations are made regarding flow management to both retain the fringe regeneration of poplars currently occurring and to stimulate more widespread regeneration of poplars on the floodplain.     

Molecular structure,DNA binding mode,photophysical properties and recommendations for use of SYBR Gold

SYBR Gold is a commonly used and particularly bright fluorescent DNA stain, however, its chemical structure is unknown and its binding mode to DNA remains controversial. Here, we solve the structure of SYBR Gold by NMR and mass spectrometry to be [2-(4-{[diethyl(methyl)ammonio]methyl}phenyl)-6-methoxy-1-methyl-4-{[(2Z)-3-methyl-1,3-benzoxazol-2-ylidene]methyl}quinolin-1-ium] and determine its extinction coefficient. We quantitate SYBR Gold binding to DNA using two complementary approaches. First, we use single-molecule magnetic tweezers (MT) to determine the effects of SYBR Gold binding on DNA length and twist. The MT assay reveals systematic lengthening and unwinding of DNA by 19.1° ± 0.7° per molecule upon binding, consistent with intercalation, similar to the related dye SYBR Green I. We complement the MT data with spectroscopic characterization of SYBR Gold. The data are well described by a global binding model for dye concentrations ≤2.5 μM, with parameters that quantitatively agree with the MT results. The fluorescence increases linearly with the number of intercalated SYBR Gold molecules up to dye concentrations of ∼2.5 μM, where quenching and inner filter effects become relevant. In summary, we provide a mechanistic understanding of DNA-SYBR Gold interactions and present practical guidelines for optimal DNA detection and quantitative DNA sensing applications using SYBR Gold.     

Niche divergence by deep‐sea octocorals in the genus Callogorgia across the continental slope of the Gulf of Mexico

Environmental variables that are correlated with depth have been suggested to be among the major forces underlying speciation in the deep sea. This study incorporated phylogenetics and ecological niche models (ENM) to examine whether congeneric species of Callogorgia (Octocorallia: Primnoidae) occupy different ecological niches across the continental slope of the Gulf of Mexico (GoM) and whether this niche divergence could be important in the evolution of these closely related species. Callogorgia americana americana, Callogorgia americana delta and Callogorgia gracilis were documented at 13 sites in the GoM (250–1000 m) from specimen collections and extensive video observations. On a first order, these species were separated by depth, with C. gracilis occurring at the shallowest sites, C. a. americana at mid‐depths and C. a. delta at the deepest sites. Callogorgia a. delta was associated with areas of increased seep activity, whereas C. gracilis and C. a. americana were associated with narrow, yet warmer, temperature ranges and did not occur near cold seeps. ENM background and identity tests revealed little to no overlap in ecological niches between species. Temporal calibration of the phylogeny revealed the formation of the Isthmus of Panama was a vicariance event that may explain some of the patterns of speciation within this genus. These results elucidate the potential mechanisms for speciation in the deep sea, emphasizing both bathymetric speciation and vicariance events in the evolution of a genus across multiple regions.     

Evidence suggesting direct oxidation of human erythrocyte membrane sulfhydryls by copper

Results are presented which suggest that cupric ion can directly oxidize the sulfhydryls of human erythrocyte membrane proteins leading to the formation of disulfide links. When packed ghosts were incubated in cupric sulfate (0.3 to 0.7 mM) at pH 8, and electrophoresed on sodium dodecyl sulfate polyacrylamide gels in the absence of dithiothreitol bands 1, 2 (spectrin); 4.2 and 5 (actin) diminished in intensity concomitant with the appearance of high molecular weight material. Band 3 moved to its dimeric position on the gel. Evidence that these crosslinks result from formation of new disulfide links due to direct copper binding includes: (a) reversal of crosslinking upon addition of dithiothreitol; (b) blockage of the effect by N-ethylmaleimide, EDTA and mercuric chloride. The effect of copper was observed under N₂, suggesting that it is not related to air oxidation. Furthermore, the crosslinking effect does not require high copper concentrations if the ghost concentration is low. The possible implication of these results with regard to copper induced hemolytic anemias is briefly discussed.