Quest for wine yeasts—An old story revisited

Numerous studies have described the yeast biota of grapes, and grape must in order to understand better the succession of yeasts during fermentation of wine. The origin of the wine yeasts has been rather controversial. By using more elaborate isolation methods, classical genetic analysis and electrophoretic karyotyping of monosporic clones, with this study, credible proof now exists that the vineyard is the primary source for the wine yeasts and that strains found on the grapes can be followed through the fermentation process.     

The environmental significance of algae in the mi Llandovery succession of the central Oslo Region

Girvanella , micritization phenomena and the dasycladacean alga Cyclocrinites are found in the middle Llandovery succession of the central Oslo Region. Both Girvanella and micritization phenomena occur in carbonate-dominated sequences where sedimentary structures and associated faunas suggest depositional environments above normal wave base. In contrast, Cyclocrinites occurs in shale-dominated sequences where other evidence suggests quiet, deep-water environments. We suggest that Cyclocrinites would not normally be preserved in situ in its life environment in relatively turbulent shallow waters. Preservation most commonly resulted from post mortem transport into low-energy muddy environments devoid of in situ algal activity. The resultant fossil is a flattened cast of this originally spherical alga.     

Cloning, expression, purification, and characterization of the acid alpha-mannosidase from Trypanosoma cruzi

The acid alpha-mannosidase of Trypanosoma cruzi is a broad-specificity hydrolase involved in the catabolism of glycoconjugates, presumably in the digestive vacuole. We have cloned the alpha-mannosidase gene from a T.cruzi epimastigote genomic library. The alpha-mannosidase gene was determined to be single copy by Southern analysis, and similar sequences were not detected in genomic digests of either Trypanosoma brucei or Leishmania donovani. The coding region was subcloned into the Pichia pastoris expression vector pPICZ, and alpha-mannosidase activity was detected in the medium of induced cultures. The recombinant alpha- mannosidase demonstrated a pH optimum, inhibition by swainsonine, Km, and substrate specificity consistent with the characteristics of the alpha-mannosidase previously purified from T.cruzi epimastigotes. The recombinant enzyme was purified 103-fold from the culture medium of Pichia pastoris and had a native molecular mass of 359 kDa by gel filtration. A combination of SDS-PAGE, deglycosylation with endo H, and NH2-terminal sequencing indicates that the enzyme is originally synthesized as a homodimeric polypeptide that is subsequently cleaved to form a heterotetramer composed of 57 and 46 kDa subunits. A polyclonal antibody raised to the recombinant enzyme was shown to immunoprecipitate the alpha-mannosidase from T.cruzi cell extracts and will be used in future immunolocalization studies.      

Insecticidal effects of selected biological control agents on the larvae of Plutella xylostella (Lepidoptera: Plutellidae)

To identify a more effective and safe biological control agent against a common cabbage pest, Plutella xylostella (L.) (Lepidoptera: Plutellidae), the insecticidal effects of selected biological agents were evaluated. The highest insecticidal effects determined were 100, 73.5, 45.5, 47 and 55.3% using toxin HD‐1 (isolated from the Harry Dumagae strain of Bacillus thuringiensis), toxin BTS‐1 (isolated from the tenebrionis strain of B. thuringiensis), B. thuringiensis Berliner, B. thuringiensis israelensis and B. thuringiensis kurstaki, respectively.     

Effects of four Bacillus spp. of soil origin on the Colorado potato beetle Leptinotarsa decemlineata (Say)

Four species of Bacillus were isolated from soil in an effort to find safe, effective and alternative biological control agents against plant pests. These bacteria were identified as Bacillus pumilus, Bacillus sphaericus, Bacillus megaterium and Bacillus cereus on the basis of fatty acid methyl ester analysis and carbon utilization profiles by using Microbial Identification and Biolog Microplate Systems. Laboratory experiments carried out to determine the insecticidal activities of these isolates showed that B. pumilus caused 95.7 and 26.7% mortality and B. sphaericus caused 74.5 and 23.3% mortality of Leptinotarsa decemlineata larvae and adults, respectively. B. cereus and B. megaterium showed 51.1 and 29.7%, respectively, of L. decemlineata larvae. This study presents at least two Turkish isolates from the genus Bacillus showing high insecticidal activity against L. decemlineata.     

Reliability and validity of a histologic score as a marker for skin cancer chemoprevention studies

OBJECTIVE: To develop a reliable and valid scoring system for grading skin biopsies from actinic keratosis (AK) and sun-damaged skin for use in evaluating the efficacy of skin cancer chemopreventive agents. STUDY DESIGN: A panel of dermatopathologists developed histologic criteria and diagnostic definitions for the progression of lesions from early AK to AK. The criteria were then applied to a sample of 335 histologic slides from an ongoing chemoprevention study. A 10% sample of 35 slides was reread in order to assess intrarater reliability. RESULTS: Six of the 7 criteria demonstrated high reliability (> 85%). The total histologic score, calculated using the 6 criteria, was found to significantly differentiate between (blinded) biopsy location (normal, pre-AK, AK and adjacent to squamous cell carcinoma) and histologic diagnosis (normal, pre- or early AK, AK and squamous cell carcinoma). CONCLUSION: The total histologic score, having demonstrated reliability on repeated readings and validity in its association with biopsy location and histologic score, is a reliable and valid end point for judging the efficacy of agents in skin cancer chemoprevention studies. Additional interrater reliability tests utilizing larger test sets and a rigorous statistical design should be undertaken to establish its portability.     

Capsule Type of Streptococcus pneumoniae Determines Growth Phenotype

The polysaccharide capsule of Streptococcus pneumoniae defines over ninety serotypes, which differ in their carriage prevalence and invasiveness for poorly understood reasons. Recently, an inverse correlation between carriage prevalence and oligosaccharide structure of a given capsule has been described. Our previous work suggested a link between serotype and growth in vitro. Here we investigate whether capsule production interferes with growth in vitro and whether this predicts carriage prevalence in vivo. Eighty-one capsule switch mutants were constructed representing nine different serotypes, five of low (4, 7F, 14, 15, 18C) and four of high carriage prevalence (6B, 9V, 19F, 23F). Growth (length of lag phase, maximum optical density) of wildtype strains, nontypeable mutants and capsule switch mutants was studied in nutrient-restricted Lacks medium (MLM) and in rich undefined brain heart infusion broth supplemented with 5% foetal calf serum (BHI+FCS). In MLM growth phenotype depended on, and was transferred with, capsule operon type. Colonization efficiency of mouse nasopharynx also depended on, and was transferred with, capsule operon type. Capsule production interfered with growth, which correlated inversely with serotype-specific carriage prevalence. Serotypes with better growth and higher carriage prevalence produced thicker capsules (by electron microscopy, FITC-dextran exclusion assays and HPLC) than serotypes with delayed growth and low carriage prevalence. However, expression of cpsA, the first capsule gene, (by quantitative RT-PCR) correlated inversely with capsule thickness. Energy spent for capsule production (incorporation of H3-glucose) relative to amount of capsule produced was higher for serotypes with low carriage prevalence. Experiments in BHI+FCS showed overall better bacterial growth and more capsule production than growth in MLM and differences between serotypes were no longer apparent. Production of polysaccharide capsule in S. pneumoniae interferes with growth in nutrient-limiting conditions probably by competition for energy against the central metabolism. Serotype-specific nasopharyngeal carriage prevalence in vivo is predicted by the growth phenotype.     

Complete intra-annual cycle of leaf area index in a Platanus orientalis L. stand

Leaf area index (LAI) analysis of deciduous forest trees is usually restricted to seasonal monitoring involving the assessment of distinct leaf phenological stages within definite time intervals of the year. However, continuous LAI monitoring that includes entire leaf periods is necessary to define the ecophysiological characteristics of deciduous trees. Therefore, this study investigated the intra-annual cycle of the LAI for a Platanus orientalis L. stand in the Bart?n watershed of Turkey. A complete cycle involves three periods: foliation, stable, and defoliation. The foliation period comprises budburst, leaf emergence and flushing sessions, whereas the defoliation period consists of leaf senescence and leaf fall sessions. The stable period is in between these two periods when LAI values are at a climax around maximum. Eight points were determined in the field for the analysis of LAI by a hemispherical photography technique. Over a relatively frequent schedule, photographs were taken almost weekly during the foliation period. Both weekly and approximate monthly photographs were applied during the stable period. Finally, near-monthly photographs were taken for the defoliation period. The foliation period lasted for about 1.5 months from mid-April to May with the mean LAI reaching from 0.16 up to 2.38. Mean LAI was between 2.38 and 2.47 for a stable period over 2 months (June and July). For the defoliation period, mean LAI dropped from 2.42 down to 0.35 over 5 months from August to December. The total foliated period was more than 8 months, which is relatively long for a temperate forest. In addition, correlations between mean LAI and maximum, mean and minimum temperatures were highly significant (P < 0.01) with coefficients (r) of 0.79, 0.90 and 0.93, respectively. By describing the intra-annual LAI pattern, this study fills a gap in the literature on the phenology of Platanus orientalis L.     

A framework for community and ecosystem genetics: from genes to ecosystems

Can heritable traits in a single species affect an entire ecosystem? Recent studies show that such traits in a common tree have predictable effects on community structure and ecosystem processes. Because these 'community and ecosystem phenotypes' have a genetic basis and are heritable, we can begin to apply the principles of population and quantitative genetics to place the study of complex communities and ecosystems within an evolutionary framework. This framework could allow us to understand, for the first time, the genetic basis of ecosystem processes, and the effect of such phenomena as climate change and introduced transgenic organisms on entire communities.