Potentiality of the cox1 gene in the taxonomic resolution of soil fungi

We explored the potential of the cox1 gene in the species resolution of soil fungi and compared it with the nuclear internal transcribed spacer (ITS) and small subunit (SSU)-rDNA. Conserved primers allowing the amplification of the fungal cox1 gene were designed, and a total of 47 isolates of Zygomycota and Ascomycota were investigated. The analysis revealed a lack of introns in >90% of the isolates. Comparison of the species of each of the six studied genera showed high interspecific sequence polymorphisms. Indeed, the average of nucleotide variations (4.2–11%) according to the genus, due mainly to the nucleotide substitutions, led to the taxonomic resolution of all the species studied regarding both ITS and SSU-rDNA, in which <88% were discriminated. The phylogenetic analysis performed after alignment of the cox1 gene across distant fungal species was in accordance with the well-known taxonomic position of the species studied and no overlap was observed between intra- and interspecific variations. These results clearly demonstrated that the cox1 sequences could provide good molecular markers for the determination of the species composition of environmental samples and constitute an important advance to study soil fungal biodiversity.     

Serotonin transporter gene,childhood emotional abuse and cognitive vulnerability to depression

Meta‐analyses evaluating the association between the serotonin transporter polymorphism (5‐HTTLPR) with neuroticism and depression diagnosis as phenotypes have been inconclusive. We examined a gene–environment interaction on a cognitive vulnerability marker of depression, cognitive reactivity (CR) to sad mood. A total of 250 university students of European ancestry were genotyped for the 5‐HTTLPR, including SNP rs25531, a polymorphism of the long allele. Association analysis was performed for neuroticism, CR and depression diagnosis (using a self‐report measure). As an environmental pathogen, self‐reported history of childhood emotional abuse was measured because of its strong relationship with depression. Participants with the homozygous low expressing genotype had high CR if they had experienced childhood emotional maltreatment but low CR if they did not have such experience. This interaction was strongest on the Rumination subscale of the CR measure. The interaction was not significant with neuroticism or depression diagnosis as outcome measures. Our results show that 5‐HTTLPR is related to cognitive vulnerability to depression. Our findings provide evidence for a differential susceptibility genotype rather than a vulnerability genotype, possibly because of the relatively low levels of abuse in our sample. The selection of phenotype and environmental contributor is pivotal in investigating gene–environment interactions in psychiatric disorders.     

Identification of differential genes in the ovary relative to the testis and their expression patterns in half-smooth tongue sole (Cynoglossus semilaevis)

Half-smooth tongue sole (Cynoglossus semilaevis) is a rare marine flatfish whose mature ovary and testis greatly differ in volume and weight. The length and weight of mature females are over twice greater than those of mature males. To obtain sufficient information on gonad differentiation and the relationship between gonad development and growth in the fish, we compared gene expression between the ovary and testis using suppression subtractive hybridization (SSH). Testis cDNAs are subtracted from...     

Genetic analysis of somatic embryogenesis in carrot cell culture: Initial characterization of six classes of temperature-sensitive variants

Cell cultures of the carrot Daucus carota are a useful experimental system for studying the genetic regulation of plant embryogenesis. A modified filtration-enrichment procedure was used to isolate 21 temperature-sensitive variants in somatic embryogenesis; the variants display normal embryo development at the permissive temperature (24°C) and altered development at the restrictive temperature (33°C). Temperature-shift experiments were performed on these variants to determine the timing of gene action for the putative temperature-sensitive alleles. According to their phenotypes at the restrictive temperature, these variants can be divided into six classes: No Growth, Callus Proliferation, Globularstage Block, Oblong-stage Block, Lateral Growth, and Root Formation. Although many variants exhibit lengthy temperature-sensitive periods, the temperature sensitivity of some variants is restricted to one or two embryonic stages. These results plus those in the literature are incorporated into a preliminary model concerning the genetic regulation of carrot embryogenesis.     

Carotenoid synthesis in Streptomyces setonii ISP5395 is induced by the gene crtS, whose product is similar to a sigma factor

In many species of actinomycetes, carotenogenesis can be photoinduced. The capacity to respond to photoinduction is, however unstable and, in various strains of Streptomyces, is lost at a relatively high frequency. In Streptomyces setonii ISP5395, which normally produces no carotenoids, carotenoid-producing mutants can be obtained following protoplast regeneration. We report here the characterization of a gene, crtS, which was isolated from one such mutant and can confer on wild-type S. setonii ISP5395 cells the capacity to synthesize carotenoids. Sequence analysis of crtS reveals an open reading frame, which shows homology to genes that encode alternative sigma factors in Bacillus subtilis. We propose that crtS encodes a sigma factor which is necessary for the expression of a cryptic gene(s) for carotenoid biosynthesis in S. setonii ISP5395.     

Predictivity of an in vitro model for acute and chronic skin irritation (SkinEthic) applied to the testing of topical vehicles

An in vitro human reconstructed epidermis model (SkinEthic) used for screening acute and chronic skin irritation potential was validated against in vivo data from skin tolerability studies. The irritation potential of sodium lauryl sulfate (SLS), calcipotriol and trans-retinoic acid was investigated. The in vitro epidermis-like model consists of cultures of keratinocytes from human foreskin on a polycarbonate filter. The modulation of cell viability, the release and gene expression of proinflammatory cytokines, interleukins 1α and 8, and morphological changes were evaluated during 3 days as endpoints representative for an inflammatory reaction. The cumulative irritation potential of the topical products was evaluated in a human clinical study by visual scoring and biophysical measurement of inflammatory skin reaction after repeated 24 h applications over 3 weeks under Finn chamber patches. All topical products that were nonirritating in the human study were noncytotoxic and did not induce cytokine expression in the in vitro acute model (day 1 exposure). All irritating controls exhibited specific cell viability and cytokine patterns, which were predictive of the in vivo human data. The ranking of mild to moderate skin irritation potential was based on the lack of cytotoxicity and the presence of cytokine patterns including gene expression specific for each irritant, using the chronic in vitro model (up to 3 days exposure). The human reconstructed epidermis model SkinEthic was shown to be a reliable preclinical tool predicting the irritation potential of topical products. Moreover, it is a useful model in a two-step tiered strategy for screening acute and chronic irritation potential for the selection of vehicles for new topical drugs. This revised version was published online in July 2006 with corrections to the Cover Date.