CART peptides: regulators of body weight, reward and other functions.

Over the past decade or so, CART (cocaine- and amphetamine-regulated transcript) peptides have emerged as major neurotransmitters and hormones. CART peptides are widely distributed in the CNS and are involved in regulating many processes, including food intake and the maintenance of body weight, reward and endocrine functions. Recent studies have produced a wealth of information about the location, regulation, processing and functions of CART peptides, but additional studies aimed at elucidating the physiological effects of the peptides and at characterizing the CART receptor(s) are needed to take advantage of possible therapeutic applications.

Maternal separation alters serotonergic transporter densities and serotonergic 1A receptors in rat brain.

RATIONALE: The basic mechanisms underlying the association between early life maternal separation and adulthood psychiatric disorders are largely unknown. One possible candidate is the central serotonergic system, which is also abnormal in psychiatric illnesses. Neuroadaptational changes in serotonergic transporter and serotonergic 1A receptors may underlie links between early life stress and adulthood psychiatric disorders. OBJECTIVE: The aim of this study was to investigate the consequences of a rat model of maternal separation on serotonergic transporter and serotonergic 1A receptor densities and function in adult rat forebrain. METHODS: Rat pups were separated from dams from postnatal day 2 to postnatal day 14, each day, for zero time, 15 min and 180 min to determine the time-course of effects. A non-handled group was added to control for the effects of handling by an experimenter compared with the animal facility-reared group. Quantitative [(125)I]3beta-(4-iodophenyl)tropan-2beta-carboxylic acid methyl ester and [(125)I]-mPPI autoradiography was used to determine serotonergic transporter and serotonergic 1A densities, respectively. Adult rats were challenged with saline or serotonergic 1A agonist (+) 8-hydroxy-2-(di-n-propylamino)tetralin, 0.4 mg/kg, s.c.) and plasma adrenocorticotropic hormone and corticosterone were determined. RESULTS: serotonergic transporter and serotonergic 1A densities were significantly lower in the non-handled group in the paraventricular, arcuate, dorsomedial and ventromedial nuclei of the hypothalamus. The non-handled group also displayed lower serotonergic transporter and serotonergic 1A densities in the basolateral anterior, basolateral ventral and basomedial amygdaloid nuclei. Serotonergic transporter densities were also decreased in the CA3 area of the hippocampus in the non-handled group. In contrast, the maternal separation 15 min group displayed the highest serotonergic transporter and serotonergic 1A densities in the basomedial nucleus of amygdala, basolateral anterior nucleus of amygdala, basolateral ventral nucleus of amygdala and basomedial nucleus of amygdala amygdaloid nuclei. CONCLUSIONS: Early life maternal separation and the extent of handling can alter adult brain serotonergic transporter and serotonergic 1A levels and function in the forebrain. Alterations in these serotonergic systems by early rearing conditions might increase vulnerability for behavioral disorders in adulthood.

Cryopreservation of spores of Dicksonia sellowiana: an endangered tree fern indigenous to South and Central America.

Spores of Dicksonia sellowiana (Presl.) Hook., an endangered tree fern, were stored in liquid nitrogen. Surface sterilized spores were placed in 1 ml sterile polypropylene cryotubes and were plunged into liquid nitrogen cryo-cans for 15 minutes, 15 days, 1 month and 3 months. In all, of the treatments the percentage of germination was higher than the control (fresh spores). Germination in Dyer and MS media supplement with 10 (-7) M and 5 x 10(-7) M BA was also promoted as comparing to control. There was no difference between the germination of spores thawed rapidly in a water bath at 45 degree C during 5 minutes or slowly at room temperature. Cryopreservation seems to promote germination of some dormant spores of D. sellowiana. The pre-treatment in cryoprotective solution of dimethyl sulphoxide 15%(v/v) in 1 M glycerol inhibited the germination of cryopreserved spores

Regulation of cocaine- and amphetamine-regulated transcript mRNA expression by calcium-mediated signaling in GH3 cells.

Cocaine- and amphetamine-regulated-transcript (CART) peptides are associated with multiple physiological processes, including, feeding, body weight, and the response to drugs of abuse. CART mRNA and peptide levels and the expression of the CART gene appears to be under the control of a number of extra- and intra-cellular factors including the transcription factor, cAMP response element binding protein (CREB). Similar to the effects of CART, Ca(2+) signaling leads to the phosphorylation of CREB and has been associated with both feeding and the actions of psychostimulants; therefore, we hypothesized that Ca(2+) may play a role in CART gene regulation. We used real-time PCR (rtPCR) and GH3 cells to examine the effect of ionomycin, which increases intracellular Ca(2+), on CART mRNA levels. Ionomycin increased CART mRNA in a dose- and time-dependent manner. The effect of ionomycin appeared transient as CART mRNA had returned to control levels 3 h following treatment. Calmidazolium and KN93, inhibitors of calmodulin and Ca(2+)-modulated protein (CaM) kinases respectively, attenuated the effect of ionomycin (10 microM) on CART mRNA levels suggesting a calmodulin-dependent mechanism. Western immunoblotting indicated that ionomycin increased phosphorylated cAMP response element binding protein (pCREB) levels and electrophoretic mobility shift assay/supershift assay using antibodies against pCREB demonstrated increased levels of a CART oligo/pCREB protein complex. Finally, we showed that injection of ionomycin into the rat nucleus accumbens increases CART mRNA levels. To our knowledge, this is the first study providing evidence that the CART gene is, in part, regulated by Ca(2+)/CaM/CREB-dependent cell signaling.

Characterizing a stable methane-utilizing mixed culture used in the synthesis of a high-quality biopolymer in an open system.

AIMS: To characterize a methane-utilizing poly-beta-hydroxybutyrate (PHB)-producing microbial community. METHODS AND RESULTS: Three different approaches based on microbiology, analytical chemistry and molecular biology were used to determine the composition of the mixed culture. The dominant species, Methylocystis sp. GB25, represents more than 86% of the total biomass. Seven accompanying bacterial species are present in the mixed culture of which two are methylotrophic bacteria and five are utilizers of complex carbon sources. Both these groups were found to be present at the same ratio with respect to each other. Results of fatty acid analysis and PCR-DGGE fingerprints reflect the stability of the mixed-culture composition in the open system during multiple continuous growth and polymer formation processes throughout a period of 29 months. The consistently high quality of the accumulated polymer further corroborates this finding. CONCLUSION: The methane-utilizing mixed culture has the potential of self-regulation resulting in a stable composition even under non-aseptic conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: Avoiding the necessity of sterile conditions, as demonstrated in this paper, is an important step towards the development of a viable large-scale process for the production of PHB using cheap substrates like methane from natural or renewable sources. This is the first report characterizing a bacterial mixed culture being used for the biotechnological production of a high-value product in an open system.

Yield coefficients in dependence on milieu conditions and cell states. III. Induction of synchrony in continuous yeast cell cultivation by milieu changes.

Induction of synchrony by various perturbations in continuous yeast cultivation on hydrocarbons of crude oil is described. Short-time temperature and pH-value shocks cause oscillations of budding cell percentage in the order of the cell cycle duration. An abrupt change of the phosphate ion concentration of the nutritional medium may also induce a synchronization of microbial growth. However, the frequency corresponds with the eigenfrequency of the fermentation process. The experimental values were investigated statistically using autocorrelation and spectral analysis.

[Theoretical determination of the energy efficiency of microbial carbon substrate conversion and comparison with experimental values in phase cultures]. / Theoretische Bestimmung energetischer Wirkungsgrade der mikrobiellen Kohlenstoffsubstratwandlung und Vergleich mit experimentellen Werten an Phasenkulturen.

The phenomenological description of microbial substrate conversion is possible by connecting energy and material balance equations. The change of free enthalpy of microbial substrate conversion was determined on the basis of exact material balance equations. A simultaneous determination of heat production allowed to calculate the energetic efficiency of microbial growth processes. In addition to this the change of free enthalpy by microbial substrate conversion was standardized by the free standard formation enthalpy of biomass. Both quantities were used for comparing microbial combustion of several substrates into biomass. Comparable with the concept of substrate combustion enthalpy standardized by the combustion enthalpy of biomass an optimal strategy of mixing different substrates can be deduced from energy and material balance equations on the basis of theoretic consumption coefficients. Besides the energetic efficiency the binding state of the substrate is important in the search for optimal substrate mixing ratios. This could be shown by experimental work. Thus, the fermentation systems sucrose/yeast, paraffin/yeast, and sucrose/paraffin/yeast were studied using synchronous populations produced by the method of phased cultures. The investigations of real fermentation systems confirm the theoretical predictions on special conditions.

Yield coefficients in dependence on milieu conditions and cell states. II. Influence of perturbations on continuous cultivation of the yeast Lodderomyces elongisporus on hydrocarbons.

The influence of perturbations on continuous yeast cell cultivations on hydrocarbons of crude oil is described. Due to such perturbations the fermentation system leaves its steady state, passes through transitional stages and reaches a new steady state. In the transitional stages a damped oscillation of biomass concentration, percentage of budding cells, oxygen consumption rate, and heat flow is observed. These results can be explained by partial synchronization of yeast cell functions in microorganism populations. In phases of partial synchronization the cell cycle of a single cell is reflected by the behaviour of the microorganism population. The adaptation of the carbon substrate feeding rate to the state of partially synchronized microorganism population makes possible lower specific substrate consumption in biomass production.