Ploidy and chromosomal number in Tuber aestivum

Chromosome number is generally considered to be the most accurate and direct measure of ploidy. In fungi, however, counting of chromosomes is difficult and inaccurate because of their small size. To date truffles have been characterized using molecular approaches (analysis of DNA and PCR-based techniques) in order to find out differences among species, but not by a cytogenetical approach. Although the small size of truffle chromosomes is of some hindrance for a cytogenetic study, in the present work Tuber aestivum chromosome counts were determined in metaphase configurations from haploid nuclei of ascospores by aceto-orcein staining. Nuclear chromosome number and topography were also evaluated by propidium iodide DNA staining using confocal microscopy. Tuber aestivum was found to possess a basic number of 5 or 6 chromosomes, medium length ≤0.95 μm. The karyology of ascospores during their developmental stages was also investigated.     

sacA and nisA genes are not always linked in Lactococcus lactis subsp. lactis strains

Sixty-seven lactococcal strains arising from dairy habitat were screened for the presence of the sucrose 6-phosphate hydrolase gene by polymerase chain reaction. Of the strains tested, 35.8% were able to ferment sucrose as well as to harbour the sucrose-6-phosphate hydrolase gene, even though they were unable to produce nisin as well as to show the nisin structural gene. After pulsed-field gel electrophoresis and hybridisation all Suc⁺Nis⁻ strains exhibited physical linkage between sacA gene and the left end of lactococcal transposons (Tn5276 or Tn5301) without linkage to nisin genes. However, we were unable to transfer the sacA gene as well as to detect Suc⁻ derivatives from Suc⁺Nis⁻ strains after conjugation and curing experiments.     

Bacterial aerosol emission from wastewater treatment plants:Culture methods and bio-molecular tools

In this report we describe the results of a studyconducted in order to better estimate airbornemicroorganisms. A method based on a bio-moleculartechnique, Polymerase Chain Reaction (PCR) wascompared with the culture methods based on the viablecounts of total and fecal bacteria. Microbial aerosolemission from the surfaces of aeration tanks of anindustrial and municipal wastewater treatment plant(Como, Italy), at different seasons, was determined.This study was accomplished by conducting test runs inwhich SAS (Surface Air Systems, PBI) viable sampler,Sartorius MD8 with membrane gelatine filter andgravity method with Petri dishes were used to collectbacterial aerosol samples in situ. Total aerobicheterothropic bacteria, Mycetes, total and fecalcoliforms were determined. The preliminary resultsshow that: no correlation was found between the twodifferent passive and active culture techniques, dueto the different mechanisms of capture of bioaerosolagents on the media; optimal values for the recoveryof E. coli viable bacteria by MD8 samplerwith gelatine membrane, time and temperature ofstorage, were recognised. For the PCR technique, acouple of primers (URL 301–URR 432) to detect E. coli, on definite air samples, was used, operativeconditions were defined, and then, applied inmonitoring on in situ bioaerosol samples. At thewastewater plant, the highest total aerobic bacteriaemission rate during the preliminary mechanicaltreatments and in correspondence of the enclosedactivated sludge phase, as a consequence of theremarkable aeration of the tanks, were registered. Thesensitivity (82 CFU/m³) and rapidity (less than 8hours) of the biomolecular methods to determine thepresence and the fecal coliforms (E. coli) ratein bioaerosols was considered satisfactory.     

The acetylcholine, GABA, glutamate triangle in the rat forebrain

The present overview demonstrates that stress, fear, novelty, and learning processes are associated with arousal and increases of extracellular levels of cortical and hippocampal ACh, independently of increases of motor activity. Forebrain cholinergic systems appear to be regulated by GABAergic and glutamatergic inputs. However, several other neurotransmitter systems play a role.

Résumé

Nous résumons ici un ensemble de résultats qui démontrent que le stress, la peur, la nouveauté, et les processus d'apprentissage sont associés a l'éveil et à une augmentation des niveaux d'acétylcholine extracellulaire dans l'hippocampe et le cortex, indépendamment de l'augmentation d'activité motrice. Le système cholinergique du cerveau antérieur semble être contrôlé par l'innervation GABAergique et glutamatergique. Cependant, plusieurs autres systèmes de neurotransmetteurs interviennent également.     

Simultaneous determination of rufloxacin, fenbufen and felbinac in human plasma using high-performance liquid chromatography

A simple, specific and sensitive high-performance liquid chromatographic method has been developed for the simultaneous determination of rufloxacin, fenbufen and felbinac in human plasma. Plasma, spiked with internal standard, was vortex-mixed for 1 min with a mixture of dichloromethane-diethyl ether (80:20, v/v). The evaporated extract was dissolved in 0.02 M NaOH. Drugs were resolved at room temperature on a 5 μm Zorbax SAX column (250×4.6 min I.D.) equipped with a 20×4.6 mm anion-exchange Vydac AXGU ( 10 μm particle size) precolumn. The mobile phase consisted of acetonitrile and phosphate buffer (pH 7.0), delivered at a flow-rate of 1.2 ml/min. Detection was made at 280 nm, 2-[4-(2′-Furoyl)phenyl]propionic acid was used as internal standard. The calibration curve was linear from 0.2 to 10μg/ml for rufloxacin, from 0.5 to 30 μg/ml for fenbufen and from 0.2 to 10 μg/ml for felbinac, respectively. The detection limit was 0.1 μg/ml for rufloxacin. 0.3 μg/ml for fenbufen and 0.1 μg/ml for felbinac, respectively.     

Community isolation drives lower fish biomass and species richness,but higher functional evenness,in a river metacommunity

1. The flow of individuals among communities and their interactions with local environmental filters are increasingly recognised as determinants of biodiversity patterns in riverine ecosystems. Both incoming dispersers and local conditions are expected to systematically change along connectivity gradients from headwaters to downstream communities. However, the interplay between isolation-centrality gradients and environmental conditions as determinants of biodiversity structure and function has seldom been considered.
2. Here, we represented the dendritic structure of the Negro River basin riverscape (Uruguay) in a directed graph quantifying the isolation-centrality of each river section and evaluated the direct and indirect pathways by which riverscape structure and environmental local drivers determine fish community assembly.
3. Fish communities (n = 58) were sampled following a stratified sampling design that properly represents this isolation-centrality connectivity gradient through the riverscape. In each community, fish abundance, biomass, richness, and functional diversity were estimated, and the direct and indirect hypothesised connections among them were evaluated with structural equation models.
4. We showed that the range of isolation among river sections determines a 2-fold, 5-fold, and 25-fold variation in total fish richness, abundance, and biomass, respectively. Additionally, isolation-centrality was positively associated with local temperature and conductivity, while negatively related to local depth. These variables and taxonomic richness accounted for most of the variation in total fish biomass (81%) herein used as measurement of ecosystem function. Local fish abundance was negatively and positively associated with functional evenness and taxonomic richness, respectively. Furthermore, once the effect of isolation on biomass and richness was accounted for, an effect of diversity on biomass became evident.
5. Our results provide empirical evidence for the role of riverscape structure on taxonomic and functional diversity, biomass, and the relationship between biodiversity and ecosystem function. We emphasise that in the understanding of river biodiversity and its management, local determinants should not be considered without attention to metacommunity processes.

     

Silver(I)-organophosphane complexes of the dihydridobis(3-nitro-1,2,4-triazolyl)borate ligand. X-ray crystal structure of {[H2B(tz)2]Ag[P(m-tolyl)3]2} with the scorpionate ligand co-ordinated in an unidentate κ-N fashion

New silver(I) complexes have been synthesised from the reaction of AgNO₃, monodentate PR₃ (PR₃ = P(o-tolyl)₃, P(m-tolyl)₃, P(p-tolyl)₃, P(p-C₆H₄F), SeP(C₆H₅)₃) or bidentate tertiary (dppe = bis(diphenylphosphane)ethane, dppf = 1,1′-bis(diphenylphosphane)ferrocene) phosphanes and potassium dihydrobis(3-nitro-1,2,4-triazolyl)borate, K[H₂B(tz^NO2)₂]. These compounds have been characterized by elemental analyses, FT-IR, ESI-MS and multinuclear (¹H and ³¹P) NMR spectral data. The adduct {[H₂B(tz^NO2)₂]Ag[P(m-tolyl)₃]₂} has been characterized by single crystal X-ray studies. In the former, the H₂B(tz^NO2)₂ acts as a monodentate ligand utilizing the coordinating capability of only one of the additional (exo-) ring nitrogens to complete the coordination array about the silver atom.     

Lessons from a pilot study of transfer factor in chronic fatigue syndrome

Transfer Factor (TF) was used in a placebo controlled pilot study of 20 patients with chronic fatigue syndrome (CFS). Efficacy of the treatment was evaluated by clinical monitoring and testing for antibodies to Epstein-Barr virus (EBV) and human herpes virus-6 (HHV-6). Of the 20 patients in the placebo-controlled trial, improvement was observed in 12 patients, generally within 3-6 weeks of beginning treatment. Herpes virus serology seldom correlated with clinical response. This study provided experience with oral TF, useful in designing a larger placebo-controlled clinical trial.