EFFECTS OF INGESTION OF A CARBOHYDRATE-FAT MEAL ON THE LEVELS AND SYNTHESIS OF 5-HYDROXYINDOLES IN VARIOUS REGIONS OF THE RAT CENTRAL NERVOUS SYSTEM

—The concentrations of tryptophan, serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) in spinal cord and most brain regions increase 2 h after fasted rats begin to consume a carbohydrate-fat meal: indole levels rise in all portions of the brain studied, but the increase is not statistically significant in the hypothalamus and corpus striatum. The rate at which the brain synthesizes 5-hydroxy-indoles (as estimated in vivo by measuring 5-hydroxytryptophan accumulation following an injection of the decarboxylase inhibitor RO4-4602) is also accelerated in all of the regions in which the experimental diet elevates tryptophan, 5-HT and 5-HIAA levels. These observations indicate that the previously reported increase in brain 5-hydroxyindole levels following consumption of a protein-free meal reflects accelerated serotonin synthesis, and occurs within both the cell bodies and the terminals of serotonin-containing neurons. It is possible that diet-induced changes in neuronal serotonin levels influence the quantities of the neurotransmitter released into synapses, either spontaneously or in response to drugs.     

Neurochemical effects ofl-pyroglutamic acid

The effect ofl-pyroglutamic acid, a metabolite that accumulates in pyroglutamic aciduria, on different neurochemical parameters was investigated in adult male Wistar rats. Glutamate binding, adenylate cyclase activity and G protein coupling to adenylate cyclase were assayed in the presence of the acid.l-pyroglutamic acid decreased Na⁺-dependent and Na⁺-independent glutamate binding Basal and GMP-PNP stimulated adenylate cyclase activity were not affected by the acid. Furthermore, rats received unilateral intrastriatal injections of 10–300 nmol of bufferedl-pyroglutamic acid. Vehicle (0.25 M Tris-Cl, pH 7.35–7.4) was injected into the contralateral striatum. Neurotoxic damage was assessed seven days after the injection by histological examination and by weighing both cerebral hemispheres. No difference in histology or weight could be identified between hemispheres. These results suggest that, although capable of interfering with glutamate binding, pyroglutamate did not cause a major lesion in the present model of neurotoxicity.     

Early-Life Hepatitis E Infection in Pigs: The Importance of Maternally-Derived Antibodies

Passive immunity (PI), acquired through colostrum intake, is essential for piglet protection against pathogens. Maternally-derived antibodies (MDAs) can decrease the transmission of pathogens between individuals by reducing shedding from infected animals and/or susceptibility of naïve animals. Only a limited number of studies, however, have been carried out to quantify the level of protection conferred by PI in terms of transmission. In the present study, an original modeling framework was designed to estimate parameters governing the transmission of infectious agents in the presence and absence of PI. This epidemiological model accounts for the distribution of PI duration and two different forces of infection depending on the serological status of animals after colostrum intake. A Bayesian approach (Metropolis-Hastings algorithm) was used for parameter estimation. The impact of PI on hepatitis E virus transmission in piglets was investigated using longitudinal serological data from six pig farms. A strong impact of PI was highlighted, the efficiency of transmission being on average 13 times lower in piglets with maternally-derived antibodies than in fully susceptible animals (range: 5–21). Median infection-free survival ages, based on herd-specific estimates, ranged between 8.7 and 13.8 weeks in all but one herd. Indeed, this herd exhibited a different profile with a relatively low prevalence of infected pigs (50% at slaughter age) despite the similar proportions of passively immune individuals after colostrum intake. These results suggest that the age at HEV infection is not strictly dependent upon the proportion of piglets with PI but is also linked to farm-specific husbandry (mingling of piglets after weaning) and hygiene practices. The original methodology developed here, using population-based longitudinal serological data, was able to demonstrate the relative impact of MDAs on the transmission of infectious agents.     

Kinetics of Anti-Phlebotomus perniciosus Saliva Antibodies in Experimentally Bitten Mice and Rabbits

Background

Sand flies are hematophagous arthropods that act as vectors of Leishmania parasites. When hosts are bitten they develop cellular and humoral responses against sand fly saliva. A positive correlation has been observed between the number of bites and antibody levels indicating that anti-saliva antibody response can be used as marker of exposure to sand flies. Little is known about kinetics of antibodies against Phlebotomus perniciosus salivary gland homogenate (SGH) or recombinant salivary proteins (rSP). This work focused on the study of anti-P. perniciosus saliva antibodies in sera of mice and rabbits that were experimentally exposed to the bites of uninfected sand flies.

Methodology/Principal Findings

Anti-saliva antibodies were evaluated by ELISA and Western blot. In addition, antibody levels against two P. perniciosus rSP, apyrase rSP01B and D7 related protein rSP04 were determined in mice sera. Anti-saliva antibody levels increased along the immunizations and correlated with the number of sand fly bites. Anti-SGH antibody levels were detected in sera of mice five weeks after exposure, and persisted for at least three months. Anti-apyrase rSP01B antibodies followed similar kinetic responses than anti-SGH antibodies while rSP04 showed a delayed response and exhibited a greater variability among sera of immunized mice. In rabbits, anti-saliva antibodies appeared after the second week of exposure and IgG antibodies persisted at high levels, even 7 months post-exposure.

Conclusions/Significance

Our results contributed to increase the knowledge on the type of immune response P. perniciosus saliva and individual proteins elicited highlighting the use of rSP01B as an epidemiological marker of exposure. Anti-saliva kinetics in sera of experimentally bitten rabbits were studied for the first time. Results with rabbit model provided useful information for a better understanding of the anti-saliva antibody levels found in wild leporids in the human leishmaniasis focus in the Madrid region, Spain.     

Newly discovered penicillin acylase activity of aculeacin A acylase from Actinoplanes utahensis

Aculeacin A acylase from Actinoplanes utahensis produced by Streptomyces lividans revealed acylase activities that are able to hydrolyze penicillin V and several natural aliphatic penicillins. Penicillin K was the best substrate, showing a catalytic efficiency of 34.79 mM(-1) s(-1). Furthermore, aculeacin A acylase was highly thermostable, with a midpoint transition temperature of 81.5 degrees C.     

Combination therapy reduces self-injurious behavior in a chimpanzee (Pan Troglodytes Troglodytes): a case report

Self-injurious behavior (SIB) remains a severe and intractable abnormal behavior for nonhuman primates in diverse settings and is a significant concern for veterinarians and behavioral scientists. To date, no single pharmacological, behavioral, social, or environmental intervention method has emerged as a reliable permanent cure for treating SIB in all, or even most, individuals. Implementation and evaluation of a combination therapeutic approach to treating SIB for nonhuman primates is rare. In May 2004, a 25-year-old male chimpanzee with severe SIB (M = 2.09 episodes/day, range = 1-4 episodes/day) underwent intensive behavioral intervention that utilized a combination of techniques. The combination therapy approach entailed the following: (a) pharmacological intervention with a gamma-aminobutyric acid (GABA) analogue to treat suspected HIV-related sensory neuropathic pain, (b) positive reinforcement training, and (c) environmental enrichment, as well as social and environmental modification. The severity of SIB warranted immediate implementation of intensive combination therapy rather than a systematic evaluation of the individual treatment options. The individually tailored, multifaceted combination therapy resulted in the virtual elimination of SIB in this chimpanzee over a 2-year period.     

Botrydial is produced in plant tissues infected by Botrytis cinerea

The fungal metabolite botrydial was detected for the first time in ripe fruits of sweet pepper (Capsicum annuum) wound-inoculated with conidial suspensions of Botrytis cinerea and also in leaves of Phaseolus vulgaris and Arabidopsis thaliana inoculated without wounding. This phytotoxin was produced in soft rot regions of the infection. In C. annuum, the most aggressive isolate produced the highest botrydial concentrations in planta. The levels of botrydial produced by this isolate did not correlate with the reported relative susceptibilities of four P. vulgaris genotypes. The results suggest that botrydial is a pathogenicity factor for this fungus, but not a primary determinant of pathogenicity.     

Genetic diversity and population structure of Aeromonas hydrophila, Aer. bestiarum, Aer. salmonicida and Aer. popoffii by multilocus enzyme electrophoresis (MLEE)

Genetic diversity, genetic relationship, identification and population structure of 120 Aeromonas strains (including Aer. hydrophila, Aer. bestiarum, Aer. salmonicida and Aer. popoffii) isolated from various sources were studied by analysis of 15 genetic loci by multilocus enzyme electrophoresis (MLEE). All 15 loci were polymorphic, with an average of 9.4 alleles per locus and a mean genetic diversity (H) of 0.64. Cluster analysis defined at H < or = 0.7 differentiated most of the taxa analysed except the Aer. popoffii and Aer. bestiarum strains, which showed a close genetic relationship. Allelic frequencies of five loci (EST1, HEX, IDH, LDH1 and MDH) identified 94% of the strains. The index of association (IA) for the total sample was 2.38 and IA values calculated for the different populations were always significantly different from zero. These results suggest that the population structure of this Aeromonas sample is strongly clonal, confirm the taxonomic status of the analysed species in population genetics terms, and show the usefulness of MLEE for identifying Aeromonas species.