Resting cortisol levels and the emergence of dominant status among male vervet monkeys

Resting serum cortisol was measured in adult male vervet monkeys (Cercopithicus aethiops sabaeus) in four different conditions: (1) among groups with unaltered group membership and established dominance hierarchies; (2) among groups from which the original dominant male had been removed and in which the remaining males competed for dominant status; (3) among newly formed groups of three unfamiliar males each of which had been the dominant male in his previous group; and (4) among groups from which a dominant male was temporarily separated and returned. In Condition 1, cortisol concentrations did not differ between dominant and subordinate males. The second condition showed that cortisol levels were highest among males who eventually emerged as the dominant male. In the third condition, however, cortisol levels did not differentiate eventually dominant from eventually subordinate males. In the last condition, cortisol levels were highest in the animals that became or remained dominant following reintroduction. These data indicate that cortisol concentration does not differ between dominant and subordinate males in stable groups and that cortisol rises during competition for dominance among familiar males.     

Stimulation of Muscarinic Acetylcholine Receptors Increases Synaptosomal Free Calcium Concentration by Protein Kinase-Dependent Opening of L-Type Calcium Channels

In synaptosomes prepared from rat cerebral cortex, free cytosolic calcium concentration ([Ca2+]i) was measured using the fluorescent dye fura-2. Incubation of fura-2-loaded synaptosomes with carbachol increased [Ca2+]i in a dose-dependent manner (1-1,000 microM), with a maximum response of 22 +/- 2% at approximately 100 microM and an EC50 (calculated concentration producing 50% of the maximum response) of 30 microM. The effect of carbachol (100 microM) on [Ca2+]i was antagonised by atropine, but not by hexamethonium (10 microM). The calculated concentration of atropine needed for 50% inhibition (IC50) was 260 nM. The rise in [Ca2+]i produced by carbachol was reduced in the absence of extrasynaptosomal Ca2+ and effectively blocked by the L-type calcium channel blocker nifedipine (with an IC50 of 29 nM). The response to carbachol was reduced if the synaptosomes were preincubated with the protein kinase inhibitors H7 [1-(5-isoquinolinylsulfonyl)-2- methylpiperazine] (from 17% in the solvent control to 4%) and staurosporine (from 20% in the solvent control to 3%). These results show that stimulation of muscarinic acetylcholine receptors in synaptosomes increases [Ca2+]i by protein kinase-dependent activation of 1,4-dihydropyridine-sensitive calcium channels.     

Mycobacterium kansasii infection in squirrel monkeys (Saimiri sciureus sciureus)

Abstract: This report documents asymptomatic infections of Mycobacterium kansasii in four of five tuberculin positive squirrel monkeys (Saimiri sciureus sciureus). The mycobacterial DNA amplified by polymerase chain reaction (PCR) from a bronchial lymph node had no affinity for the species specific probes of M. tuberculosis, M. avium, and M. intracellular, thus allowing the presumptive diagnosis of an atypical mycobacterial infection. Infection by Mycobacterium kansasii was confirmed by culture of bronchial lymph nodes from three monkeys. The source of the infection was never identified.     

Renewal of opsin in the photoreceptor cells of the mosquito

Mosquito rhodopsin is a digitonin-soluble membrane protein of molecular weight 39,000 daltons, as determined by sodium dodecyl sulfate gel electrophoresis. The rhodopsin undergoes a spectral transition from R515-520 to M480 after orange illumination. The visual pigment apoprotein, opsin, is the major membrane protein in the eye. Protein synthesis in the photoreceptor cells occurs in the perinuclear cytoplasm and the newly made protein is transported to the rhabdom. Light adaptation increases the rate of turnover of this rhabdomal protein. The turnover of electrophoretically isolated opsin is also stimulated by light adaptation. The changes observed in protein metabolism biochemically, are consistent with previous morphological observations of photoreceptor membrane turnover. The results agree with the hypothesis that the newly synthesized rhabdomal protein is opsin.     

The rise and fall of pineal N-acetyltransferase in vitro: Neural regulation in the developing rat

In rats, the pineal gland has a rhythm in the activity of the enzyme, N-acetyltransferase (NAT), which is thought responsible for daily cycles of melatonin synthesis. Neonatal rat pineal glands, but not those of adult rats, have a single cycle that is observed in vitro during the first day of organ culture. The neural regulation of the cycle was investigated using neonatal rats with adult rats used for comparison. Prior treatment of rat pups with constant light did not abolish the cycle in vitro though it did abolish the in vivo rhythm. Removal of the superior cervical ganglia did not abolish the in vivo rhythm that was measured the first day after surgery, but ablation of the ganglia did abolish the rhythm if several days or more elapsed after surgery. Extirpation of the superior cervical ganglia abolished the in vitro NAT cycle in pup pineal glands as did the pharmacological equivalent, injection of 6-hydroxydopamine. Propranolol, a beta blocking agent, prevented the occurrence of the cycle in vitro.     

THE ROLE OF LIPIDS IN THE OBSERVED LACK OF PHOSPHATIDYLCHOLINE EXCHANGE IN MYELIN

Abstract— When exchange between liposomal phosphatidylcholine and that in a whole myelin fraction from guinea-pig brain was studied, very little exchange was observed. In order to investigate the reason for this phenomenon, myelin lipids in the Ca²⁺ form were prepared and subjected to sonication under the same conditions usually used to study phosphatidylcholine exchange. Despite the high cholesterol content in these extracts, this treatment produced liposomes of a size (12 nm Stoke's radius) similar to that of pure phosphatidylcholine liposomes. In this form, myelin total lipids were capable of undergoing exchange, and this was only demonstrable in the fraction containing phosphatidylcholine and that containing phosphatidylinositol. Since the level of acidic phospholipids in these total lipid extracts is potentially capable of producing 40% inhibition of phosphatidylcholine exchange (H ellings et al , 1974; B rammer & S heltawy , 1975), control experiments were carried out to ensure that the observed phosphatidylcholine exchange in the myelin lipid extract was not due to the loss of phosphoinositides. This was found to be the case, and it was concluded therefore that total myelin lipids, in the Ca²⁺ form, are capable of phosphatidylcholine exchange and that the observed lack of it in the whole myelin is due either to the effect of myelin proteins or the compact structure of the myelin membrane.
Calculations based on the difference between the rate of phosphatidylcholine exchange in the myelin liposomes and in the sonicated phosphatidylcholine liposomes indicated that the phosphatidylcholine is asymmetrically distributed in the myelin liposomes. Almost all the phosphatidylcholine seems to be present in the outer half of the bilayer.     

Correction of image instability in confocal microscopy using image realignment. Effects on the analysis of intracellular calcium

Using confocal microscopy, we have examined the increases in [Ca(2+)](i) evoked by sodium channel toxins in cells labelled with the fluorescent dye INDO-1. We describe a new image analysis method that improves the detection of region-specific, toxin-induced patterns of change of intracellular calcium. This method is based on correction of global image motion followed by calculation of the strength of correlation between calcium changes in "seed" or reference pixels chosen to represent different regions of cells and those in other regions of the image. When the selected "seed" pixel was chosen to be in either varicosities or neurites, correlations were detected in the same regions of other cells as well as in the soma, indicating specific but spatially distinct patterns of behaviour. Control images (without changes in [Ca(2+)](i)) did not reveal significant interpixel correlations. The ability to recognize correlated patterns of calcium change in different regions of cells was greatly improved by correction for global motion.     

STING Millennium Suite: integrated software for extensive analyses of 3d structures of proteins and their complexes

Background  

The integration of many aspects of protein/DNA structure analysis is an important requirement for software products in general area of structural bioinformatics. In fact, there are too few software packages on the internet which can be described as successful in this respect. We might say that what is still missing is publicly available, web based software for interactive analysis of the sequence/structure/function of proteins and their complexes with DNA and ligands. Some of existing software packages do have certain level of integration and do offer analysis of several structure related parameters, however not to the extent generally demanded by a user.     

Synthesis of 2',3'-dideoxy-2',3'-didehydro nucleosides via a serendipitous route

This paper describes a "green" synthesis of 2',3'-unsaturated 2',3'-dideoxynucleosides via an electrochemical reaction. Using this approach d4T, d4U, ddA and ddI can be synthesized in high yields.     

Genome-scale metabolic reconstruction and <Emphasis Type="Italic">in silico</Emphasis> analysis of methylotrophic yeast <Emphasis Type="Italic">Pichia pastoris</Emphasis> for strain improvement

Background  

Pichia pastoris has been recognized as an effective host for recombinant protein production. A number of studies have been reported for improving this expression system. However, its physiology and cellular metabolism still remained largely uncharacterized. Thus, it is highly desirable to establish a systems biotechnological framework, in which a comprehensive in silico model of P. pastoris can be employed together with high throughput experimental data analysis, for better understanding of the methylotrophic yeast's metabolism.