Dopamine and TSH secretion in uremic male rats

The role of dopamine in the dysregulation of TSH secretion in uremic male rats was investigated using the dopamine antagonist, pimozide. In order to obviate the effect of weight loss due to uremia-induced anorexia as a cause of altered TSH secretion in uremia, we also studied a group of normal animals whose food intake was restricted and who demonstrated weight loss comparable to that of the uremic animals. Baseline TSH concentrations were not significantly different in the normal, uremic or starved animals. Pimozide administration produced no change in the baseline TSH concentrations in any of the groups of rats. The peak TSH response to TRH (5 micrograms IV) was significantly blunted in the uremic animals compared to the normal controls and the starved animals. Pimozide administration did not alter the peak TRH-stimulated TSH response in either the normal animals or the starved animals. However, the peak TRH-stimulated TSH response was significantly increased in the uremic animals and was comparable to the peak TSH response seen in the pimozide-untreated control animals. The data suggest that experimental renal failure in rats is associated with diminished sensitivity of the thyrotroph to TRH stimulation, and that this blunted sensitivity may be dopamine-dependent since it can be abolished by pharmacologic dopamine blockade.     

Energy balance in Speliphron violaceum (Hymenoptera) and use of meconium weight as an index of bioenergetics components

Summary Speliphron violaceum deposits its larva and a few paralysed spiders inside the holes of electrical sockets. The larva feeds on the spiders, completes development in 6 days and emerges after 18 days of pupation. When provided with spiders to the maximum capacity of the hole, a larva consumed 1.746 KJ and converted 1.360 KJ. Restriction of the quantity of spiders provided, resulted in decreased consumption and extension of larval duration to 7 or 8 days. Consumption of 0.710·718 KJ was the minimum requirement for the completion of larval development. Despite variations in food consumption, assimilation efficiency of the larva remained constant around 97%. Gross production efficiency of the larvae averaged 77%. Larvae ingesting different amounts of host energy emerged with a wide range of body weight (16–62 mg). The efficiency with which pupal energy is transferred to adult was around 30%. Dry weight of meconium egested by the test individuals varied from 1.3 to 4.6 mg. Using simple regression equations, it is possible to predict the bioenergetics components of S. violaceum from the dry weight of meconium.     

Microbial deracemisation of aromatic β-hydroxy acid esters

Aromatic β-hydroxy acid esters were found to undergo deracemisation using whole cells of Candida parapsilosis. The conditions for the deracemisation reaction were optimised where 75% isolated yield and >95% enantiomeric excess of the product was achieved. The effect of electron donating as well as electron withdrawing groups present in the standard substrate, ethyl 3-hydroxy 3-phenyl propionate was studied to establish the generality of the reaction. The enantiomeric excess of the product remains high (>95%) irrespective of the different substituents in the para position but substitution at the ortho position obstructs the process. Similarly, ethyl and methyl esters of the standard substrate undergo deracemisation reaction giving high ee of the product, but the benzyl ester of the standard substrate did not undergo deracemisation.     

Structures, spectroscopy and modeling of a rare set of isomeric copper(II) complexes

The structures and spectroscopic properties of various conformations of two diasteromeric pairs of enantiomers of pentacoordinate Cu^II bispidine complexes with chiral tetradentate ligands are reported. With one of the ligands an interesting type of distortional isomerism was observed experimentally, and this was studied in detail on the basis of the experimental structural and spectroscopic data (UV-Vis-NIR, EPR) and a DFT-, MM- and ligand-field-theory-based analysis.     

Effects of interaction of ration and temperature on growth and bioenergetics of Achaea janata Linnaeus (Lepidoptera: Noctuidae)

Summary Growth and bioenergetics of the last instar larvae of Achaea janata fed on a wide range of rations of leaves of Ricinus communis (ad libitum to 50 or 100 mg leaf per larva per day) at 22, 27, 32 and 35° C were studied. Increase in larval mortality, extension of larval duration and decrease in final body weight were some of the adverse effects of restricted rations. Whereas larval duration was influenced by ration level, pupal period was dependent on temperature. The larvae partially compensated for restricted rations by enhancing feeding rate over the limit expected in proportion to the ration offered. The level of compensation was higher at 27° C. Influence of temperature or its interaction with ration on assimilation efficiency was more significant than the independent influence of ration; the efficiency ranged from 57 to 67%. Restriction of ration below a critical level (300 mg/larva/day at 35° C and 200 mg/larva/day at other temperatures) significantly influenced the net conversion efficiency; the lowest efficiency of 1.3% was recorded for the larvae fed 100 mg leaf/day. Energy content of the terminal larva determined the percentage of energy transferred to the imago, which ranged from 37 to 55% of the terminal larval energy.     

Impediment to growth and yeast-to-hyphae transition in Candida albicans by copper oxide nanoparticles

Abstract

The effects of two prominent copper oxide nanoparticles (CuO-NP and Cu₂O-NP), with the oxidation state of Cu⁺⁺ (cupric) and Cu⁺ (cuprous), on Candida albicans were evaluated. CuO-NP and Cu₂O-NP were synthesized and characterized by XRD, FESEM, HR-TEM and Zeta potential. At sub-MIC (50?µg ml^?1), both cupric and cuprous oxide NPs prevented yeast-to-hyphae switching and wrinkling behaviour in C. albicans. The mechanism for the antifungal action of the two NPs differed; CuO-NP significantly elicited reactive oxygen species, whereas membrane damage was more pronounced with Cu₂O-NP. Real time PCR analysis revealed that CuO-NP suppressed the morphological switching of yeast-to-hyphae by down-regulating cph1, hst7 and ras1 and by up-regulation of the negative regulator tup1. In comparison, Cu₂O-NP resulted in down-regulation of ras1 and up-regulation of the negative regulators nrg1 and tup1. Between the two NPs, CuO exhibited increased antifungal activity due to its stable oxidation state (Cu⁺⁺) and its smaller dimensions compared with Cu₂O-NP.