Effects of central administration of arginine vasotocin on monoaminergic neurotransmitters and energy metabolism of rainbow trout brain

In a first set of experiments, intracerebroventricular (ICV) treatment of 1 μl 100 g⁻¹ body mass of Cortland saline containing different doses (1–20 nmol μl⁻¹) of arginine vasotocin (AVT) produced after 180 min dose‐dependent changes in levels of brain neurotransmitters in several brain regions and pituitary of rainbow trout Oncorhynchus mykiss . Thus, an enhancement of serotonergic and dopaminergic activity, together with a decreased noradrenergic activity, were observed both in the hypothalamus and pituitary of AVT‐treated fish. In the other brain regions assessed, only increased serotonergic activity in the optic lobes, and decreased dopaminergic activity in the telencephalon of AVT‐treated fish were noticed. Changes observed in monoamine levels resemble those observed during osmotic adaptation of euryhaline fishes. In a second set of experiments, fish were ICV injected with AVT as described above to assess changes in several variables of brain energy metabolism. The results obtained show a dose‐dependent enhancement of brain glycogenolytic potential in the brain of AVT‐treated fish, that again resemble the changes observed in euryhaline fishes during osmotic acclimation.     

Isolation and characterization of 16 tetranucleotide microsatellite loci in the red panda (Ailurus fulgens)

A total of 15 polymorphic tetranucleotide microsatellite loci in the red panda, Ailurus fulgens, were characterized in this study. Based on evaluations of 33 red pandas, the number of observed alleles for each locus ranged from seven to 17 and the expected and observed heterozygosities were 0.412–0.897 and 0.121–0.909, respectively. The mean polymorphic information content was 0.721. These markers would greatly strengthen the utilization of microsatellite tools in genetic variation studies in red panda populations.     

Metabolic syndrome in relation to Barrett⿿s esophagus and esophageal adenocarcinoma: Results from a large population-based case-control study in the Clinical Practice Research Datalink

Gastroesophageal reflux disease (GERD) causes local chronic inflammation that increases risks of Barrett⿿s esophagus (BE) and esophageal adenocarcinoma (EA), yet symptomatic GERD is absent in approximately half of all such patients. Obesity exacerbates GERD and is also a component of metabolic syndrome (MetS). We evaluated the hypothesis that MetS is a GERD-independent mechanism by which obesity is associated with increased risks of BE and EA using data from the UK Clinical Practice Research Datalink. BE cases (n = 10,215) and EA cases (n = 592) were each individually matched to five population controls based on age, sex, and general practice. MetS was defined as occurrence of at least three of the following: obesity, type 2 diabetes, hypertension, and high cholesterol. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. MetS was marginally associated with BE (OR = 1.12, 95%CI 1.00⿿1.25). Similar effects were found for the individual component factors of obesity, hypertension, and high cholesterol. History of GERD modified the association (P-_{effect modification} <1E⿿5), with the MetS-BE association confined to patients without a history of GERD (OR = 1.33, 95%CI 1.12⿿1.58). No association between MetS and risk of EA was detected in the main or stratified analyses. In this large population-based case-control study, individuals with MetS had a marginally increased risk of BE in the absence of GERD. The systemic inflammatory state (MetS) may represent a reflux-independent inflammatory pathway that increases the risk of BE. MetS did not increase risk of EA in this study population.     

Ghrelin O-acyltransferase (GOAT) has a preference for n-hexanoyl-CoA over n-octanoyl-CoA as an acyl donor

Ghrelin is a peptide hormone in which serine 3 is modified by n-octanoic acid through GOAT (ghrelin O-acyltransferase). However, the enzymological properties of GOAT remain to be elucidated. We analyzed the in vitro activity of GOAT using the recombinant enzyme. Unexpectedly, although the main active form of ghrelin is modified by n-octanoic acid, GOAT had a strong preference for n-hexanoyl-CoA over n-octanoyl-CoA as an acyl donor. Moreover, a four-amino acid peptide derived from the N-terminal sequence of ghrelin can be modified by GOAT, indicating that these four amino acids constitute the core motif for substrate recognition by the enzyme.     

Correlations between the psychological peculiarities of an individual and the efficacy of a single neurofeedback session (by the EEG characteristics)

Modifications of different EEG rhythms induced by a single neurofeedback session (by the EEG characteristics) directed toward an increase in the ratio of the spectral powers (SPs) of the α vs θ oscillations were compared with the psychological characteristics of the tested subjects (the group included 30 persons). A generally accepted neurofeedback technique was used; the intensity of acoustic white noise served as the feedback signal. EEG potentials were recorded from the C3 and C4 leads. Psychological testing was carried out using Eysenck’s (EPQ), Rusalov’s (OST), and (16 PF) questionnaires. The directions of changes in the SPs of EEG frequency components were found to significantly correlate with some individuality-related peculiarities of the tested subjects. The SP of the δ rhythm correlated with the EPQ scale “neuroticism,” OST scale “social plasticity,” and 16 PF factors H (“parmia”), I (“premsia”), and Q₃ (“self-control of behavior”). The SP of the θ component demonstrated correlations with the OST scales “ergisity,” “plasticity,” and “social temp” and with 16 PF factors M (“autia”), Q₄ (“frustration”), and Q1 (“exvia”). The SP of the α rhythm correlated with 16 PF factors Q₃ (“self-control of behavior”), G (“strength of superEgo”), O (“hypothymia”), L (“protension”), and N (“shrewdness”). The SP of the β rhythm correlated with the OST scale “emotionality,” while that of the γ rhythm showed correlations with the 16 PF indices L (“protension”) and M (“autia”). Changes in the ratio of the α vs θ SPs correlated with the EPQ scale “neuroticism.” Thus, our data confirm the statement that a high individual variability of the results of a single (first in the series) neurofeedback session is to a great extent related to peculiarities of the individual psychological pattern of the subject. Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 239–247, May–June, 2006.     

Isolation and PCR detection of <Emphasis Type="Italic">Enterobacter sakazakii</Emphasis> in South African food products,specifically infant formula milks

Enterobacter sakazakii has recently been identified as an opportunistic pathogen. The current culture-dependent detection methods for these bacteria are time-consuming and in this study a PCR method for the detection of E. sakazakii in South African food products, including an internal amplification control (IAC) was developed. DNA was isolated and amplified from the products and they were plated on selective growth media after pre-enrichment and enrichment in Enterobacteriaceae enrichment broth. Four of the 22 products tested positive for the presence of E. sakazakii, confirmed by PCR detection and growth on selective media. The PCR method proved effective in detecting E. sakazakii in South African products after three days and could serve as an alternative for traditional microbiological techniques.     

Structural-Thermodynamic Relationships of Interactions in the N-Terminal ATP-Binding Domain of Hsp90

Despite its importance as a target in anti-cancer therapeutics and the numerous rational-based inhibitor design efforts aimed at it, there are only limited data available on structural-thermodynamic relationships of interactions of the N-terminal ATP-binding domain of Hsp90 (N-Hsp90). Here, we redress this by presenting an investigation of binding of nucleotides and ansamycin compounds to this domain. Interactions of nucleotides with N-Hsp90 are relatively weak (> 10 μM) and are strongly enthalpy driven over the temperature range 10-25 °C. Geldanamycin (GA) and its analogues 17-AAG [17-(allylamino)-17-demethoxy-GA] and 17-DMAG (17-N,N-dimethylaminoethylamino-17-demethoxy-GA) bind more strongly and have a dominant favourable enthalpic contribution over the temperature range investigated. We investigated the temperature dependence of the enthalpic contribution to binding. We found that while the ansamycin compounds have the commonly observed negative value, the nucleotides show a negligible or even a positive ΔC_p of binding. These data represent the first observation of a single binding site for which interactions with different ligands result in both negative and positive ΔC_p values. By addressing the likely impact of the potential contributions from protein-ligand interactions, we are able to attribute the anomalous ΔC_p for the nucleotides largely to a change in the conformation of the domain structure and local motion in the lid region of N-Hsp90 with the concomitant exposure of hydrophobic amino acid side chains.     

Stoichiometry of aerobic mineralization (O/C) of aquatic macrophytes leachate from a tropical lagoon (São Paulo –Brazil)

The temporal variation of stoichiometry between consumed oxygen and oxidized carbon was investigated for the aerobic mineralization of leachates from aquatic macrophytes. Seven species of aquatic plants, viz. Cabomba piauhyensis, Cyperus giganteus, Egeria najas, Eichhornia azurea, Salvinia auriculata, Scirpus cubensisand Utricularia breviscapa, were collected from Òleo lagoon located in the floodplain of Mogi-Guacu river (São Paulo State, Brazil). After being collected, the plants were washed, oven-dried and triturated. In order to obtain the leachate, the fragments were submitted to an aqueous extraction (cold). Mineralization chambers were incubated at 20 °C containing leachates dissolved in water samples from Òleo lagoon to a final concentration of ca. 200 mg l^–1on carbon basis. The chambers were maintained under aerobic conditions; the concentrations of the organic carbon (particulate and dissolved) and the dissolved oxygen were measured during approximately 80 days. Elemental analysis of the detritus and the concentrations of the remaining material (DOC and POC) were used to determine the amounts of mineralized organic carbon. The data were analyzed with first-order kinetics models, from which the daily rates of consumption (carbon and oxygen) and the stoichiometry (O/C) were determined. In the early phase of mineralization the O/C rates increased before reaching a maximum, after which they tended to decrease. For the mineralization of leachates from C. giganteus, S. auriculata and U. breviscapa, the decrease was relatively slow. For all substrata the initial values were smaller than 1, and ranged from 0.42 (S. cubensis) to 0.81 (C. piauhyensis). The maximum values were within the range from 0.58 (U. breviscapa) to 23.1 (E. najas) and at their highest 26th (C. piauhyensis) and 106th (C. giganteus) days. These variations are believed to be associated with the chemical composition of the leachates, with their transformations and alterations of metabolic pathways involved in the mineralization.     

Sizes of granular vesicles in the rat median eminence,with special reference to the zona granulosa

Summary A quantitative evaluation has been made of the sizes of neuronal granular vesicles (GV) in different (sub-)zones of the rat median eminence. On the basis of the frequency distribution of the mean sizes of the GV in the individual nerve profiles, at least 4 tentative categories of nerve profiles may be distinguished. However, available data do not permit characterization of nerve fibre categories in terms of neurohormone and/or neurotransmitter storage. From dorsal to ventral the palisade zone shows a decrease in mean size of GV; furthermore, the relative number of nerve profiles characterized by small GV (mean size smaller than 112 nm) increases. In contrast, the GV in the zona granulosa, that part of the external zone of the median eminence ventral to the palisade zone, are of relatively large size. Qualitative observations indicate that the zona granulosa may be regarded as an area for both storage and release of biologically active substances. We are grateful to Mrs. R.M.Y. Hartsteen for technical assistance, to Miss P.C. Delfos and Mr. W. van den Oudenalder for photographic assistance and to Prof. J. Moll for helpful criticism.     

The transepithelial shunt pathway in the renal proximal tubule of newt kidney

The transepithelial shunt pathway of newt proximal tubule was examined with glass micro-electrode and electron microscopic methods. The input resistance of the peritubular (basal) membrane and tubular wall were found to be $\text{4.2 ± 0.1 · 10}{}^6$ ($\text{mean ± S.E.}\text{, n = 16}$) and $\text{11.4 ± 0.2 · 10}{}^4\text{(n = 11)}$, respectively. The input resistance of the peritubular membrane was approximately 40-times larger than that of the tubular wall. When the kidneys were perfused in a lanthanum solution, the lanthanum ions were then observed in the junctional complexes and in the intercellular spaces on both the basal and apical sides. The results indicate that the electrical shunt pathway corresponds to the apical junctional complexes and the intercellular spaces, and that the tight junctions are not truly ‘tight’ for the transepithelial movement of small ions in the proximal tubule of the newt kidney.