Effect of fatty acid chain length on suppression of ghrelin and stimulation of PYY, GLP-2 and PP secretion in healthy men

We have evaluated the effects of fatty acid chain length on ghrelin, peptide YY (PYY), glucagon-like peptide-2 (GLP-2) and pancreatic polypeptide (PP) secretion and hypothesized that intraduodenal administration of dodecanoic ("C12"), but not decanoic ("C10"), acid would decrease plasma ghrelin and increase PYY, GLP-2 and PP concentrations. Plasma hormone concentrations were measured in seven healthy men during 90-min intraduodenal infusions of: (i) C12, (ii) C10 or (iii) control (rate: 2 ml/min, 0.375 kcal/min for C12/C10) and after a buffet-meal consumed following the infusion. C12 markedly suppressed plasma ghrelin and increased both PYY and GLP-2 (all P < 0.05) compared with control and C10, while C10 had no effect. Both C10 and C12 increased PP concentrations slightly (P < 0.05). We conclude that the effects of intraduodenal fatty acids on ghrelin, PYY and GLP-2 secretion are dependent on their chain length.     

Clozapine but not haloperidol suppresses the changes in the levels of neuropeptides in MK-801-treated rat brain regions

Noncompetitive NMDA receptor antagonist (+)MK-801 is known to induce neurotoxicity and schizophrenia-like symptomatology where atypical neuroleptic clozapine is effective in contrast to typical neuroleptic, haloperidol. Although neuropeptides are implicated in memory and cognition, their roles in schizophrenia are not well understood. In the present study, we therefore examined the possible roles of neuropeptides, cholecystokinin (CCK) and somatostatin (SS) in the posterior cingulate/retrosplenial cortices (PC/RSC), frontal cortex, and hippocampus of a MK-801-induced schizophrenia-like model rat brain. This study further investigated the pretreated effect of atypical versus typical neuroleptics on the peptidergic system. SS mRNA and peptide levels significantly decreased in the PC/RSC and hippocampus but not in the frontal cortex 3 days after 0.5 mg/kg MK-801 treatment whereas CCK mRNA and peptide levels significantly decreased in all of the brain regions examined. Pretreatment with clozapine but not haloperidol completely recovered the changes in both mRNA and peptide levels of SS and CCK in those brain regions. These data suggest that peptidergic system in the brain presumably plays an important role in the control of negative schizophrenia.     

The magnum-isthmus junction of the fowl oviduct participates in the formation of the avian-type shell membrane

Avian eggs possess a shell membrane in the shape of an asymmetrical ellipsoid and with a limiting membrane that is a smooth layer of homogeneous, dense materials. We describe the role of the magnum-isthmus junction (MIJ) of the oviduct in the formation of the avian-type shell membrane in the domestic fowl Gallus domesticus. The narrow width of the lumen at the MIJ indirectly participates in the determination of the asymmetrical ellipsoid shape of eggs that are encased by the egg-white layer and subsequently by the peri-albumen layer (PL) and the shell membrane. The PL reacts with Alcian blue and exists between the egg white and the limiting membrane. It is added to the ovulating egg at the MIJ and covers the outermost surface of the egg-white layer. The function of the PL is to provide a smooth surface by covering the irregular surface of the egg-white layer. The materials of the PL consist of an Alcian blue-positive polysaccharide (or glycoprotein) of 240 kDa and five proteins of 135, 116, 72, 49, and 46 kDa. The isolated materials have an affinity to bind with the egg-white mass. An antiserum against quail PL materials stains the domestic fowl PL and secretory cells of the luminal epithelium at the MIJ, and cross-reacts with the molecules of 240, 135, and 116 kDa.     

Inhibitory Effects of Akacid®plus on Growth and Aflatoxin Production by Aspergillus parasiticus

The effects of Akacid plus, a novel guanidine-based polymer first introduced as a biocidal and disinfectant agent were studied on Aspergillus parasiticus growth and its aflatoxin (AF) productivity. The fungus was cultured on yeast extract-sucrose (YES) broth in presence of various twofold serial dilutions of 25% Akacid plus (1.5-96 microL/50 mL medium) and then incubated in shaking condition with 150 rev./min at 28 degrees C for 96 h. Based on obtained results, Akacid plus was found to significantly inhibit both growth and aflatoxin B1 (AFB1) synthesis in very low concentrations in a dose-dependent manner. Fungal growth inhibition was determined in the range of 9.6-99.6% in mycelia exposed to the total concentration range of 1.5-48 microL. A final concentration of 96 microL was necessary to completely inhibit the growth of fungus. Under similar conditions, AFB1 synthesis was found to be strongly inhibited by 8.1-98.0% in presence of 1.5-24 microL Akacid plus with a maximum of 100% by 48 microL concentration. With respect to the unique physico-chemical properties of Akacid plus, its marked inhibitory effects on A. parasiticus growth and its AFB1 synthesis shown for the first time in this study make it a promising candidate for application in prevention programmes of AF contamination of susceptible crops.     

Water ingestion by rats fed a high-salt diet may be mediated, in part, by visceral osmoreceptors

After surgical removal of all salivary secretions ("desalivation"), rats increase their consumption of water while eating dry laboratory chow. In the present experiments, desalivated rats drank even more water while they ate "powdered" high-salt food (i.e., <15-mg food particles). The Na+ concentration of systemic plasma in these animals was not elevated during or immediately after the meal, which suggests that cerebral osmoreceptors were not involved in mediating the increased water intake. A presystemic osmoregulatory signal likely stimulated thirst because the Na+ and water contents of the gastric chyme computed to a solution approximately 150 mM NaCl. In contrast, desalivated rats drank much smaller volumes of water while eating "pulverized" high-salt food (i.e., 60-140-mg food particles), and the fluid mixture in the gastric chyme computed to approximately 280 mM NaCl solution. These and other findings suggest that the NaCl ingested in the powdered high-salt diet was dissolved in the gastric fluid and that duodenal osmoreceptors (or Na+-receptors) detected when the concentration of fluid leaving the stomach was elevated after each feeding bout, and promptly stimulated thirst, whereupon rats drank water until the gastric fluid was diluted back to isotonicity. However, when rats ate the pulverized high-salt diet, much of the NaCl ingested may have been embedded in the gastric chyme and therefore was not accessible to visceral osmoreceptors once it emptied from the stomach. Consistent with that hypothesis, fluid intakes were increased considerably when desalivated rats drank 0.10 M NaCl instead of water while eating either powdered or pulverized high-salt food.     

Molecular cloning and functional expression of a multifunctional triterpene synthase cDNA from a mangrove species Kandelia candel (L.) Druce

Homology based PCRs with degenerate primers designed from the conserved sequences among the known oxidosqualene cylases (OSCs) have resulted in cloning of a triterpene synthase (KcMS) from the young roots of Kandelia candel (L.) Druce (Rhizophoraceae). KcMS consists of a 2286 bp open reading frame, which codes for 761 amino acids. The deduced amino acid sequence showed 79% homology to a lupeol synthase from Ricinus communis suggesting it to be a lupeol synthase of K. candel. KcMS was expressed in a lanosterol synthase deficient yeast with the expression vector pYES2 under the control of GAL1 promoter. GC-MS analysis showed that the transformant accumulated a mixture of lupeol, beta-amyrin and alpha-amyrin in a 2:1:1 ratio, indicating that KcMS encodes a multifunctional triterpene synthase, although it showed high sequence homology to a R. communis lupeol synthase. This is the first OSC cloning from mangrove tree species.     

Biochemical activities of Iranian Mentha piperita L. and Myrtus communis L. essential oils

GC-MS analysis of essential oils of Iranian Mentha piperita and Myrtus communis extracted by hydrodistillation lead to identification of 26 and 32 compounds, respectively. The oils had good to excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus and Candida albicans with the oil of M. piperita being more active. The findings suggest feasibility of application of M. piperita oil in treatment of the infections caused by C. albicans and E. coli. D-values on exposure to M. piperita and Myrtus communis oils were (2.14 and 2.8min), (1.4 and 12.8min) and (4.3 and 8.6min) for E. coli, S. aureus and C. albicans , respectively. The oils were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical scavenging and beta-carotene/linoleic acid systems. M. piperirta oil exerted greater antioxidant activity than that of M. communis. Phytochemical and phytobiological characteristics of these oils may lead to extraction and production of active compounds in single or combined forms with useful applications.     

Short synthesis of 16beta-hydroxy-5alpha-cholestane-3,6-dione a novel cytotoxic marine oxysterol

The first and short synthesis of 16beta-hydroxy-5alpha-cholestane-3,6-dione 1 a metabolite from marine algae, has been achieved in six steps from readily available diosgenin 5. Selective deoxygenation of primary alcohol of triol 6 has been accomplished in one step using Et(3)SiH and catalytic amount of B(C(6)F(5))(3) to produce compound 9 in high yield. Oxidation of 11 with PCC, allowed the introduction of 3,6-ene-dione functionality, and further catalytic hydrogenation and deprotection furnished the 3,6-diketo steroid 1.     

Analysis of Non-stationary Data for Heart-rate Fluctuations in Terms of Drift and Diffusion Coefficients

We describe a method for analyzing the stochasticity in non-stationary data for the beat-to-beat fluctuations in the heart rates of healthy subjects, as well as those with congestive heart failure. The method analyzes the return time series of the data as a Markov process, and computes the Markov time scale, i.e., the time scale over which the data are a Markov process. We also construct an effective stochastic continuum equation for the return series. We show that the drift and diffusion coefficients, as well as the amplitude of the return time series for healthy subjects are distinct from those with CHF. Thus, the method may potentially provide a diagnostic tool for distinguishing healthy subjects from those with congestive heart failure, as it can distinguish small differences between the data for the two classes of subjects in terms of well-defined and physically-motivated quantities. PACS: 05.10.Gg 05.40.-a, 05.45.Tp, 87.19.Hh