The fungus Botrytis cinerea is the causal agent of the economically important gray mold disease that affects more than 200 ornamental and agriculturally important plant species. B. cinerea is a necrotrophic plant pathogen that secretes nonspecific phytotoxins, including the sesquiterpene botrydial and the polyketide botcinic acid. The region surrounding the previously characterized BcBOT1 gene has now been identified as the botrydial biosynthetic gene cluster. Five genes including BcBOT1 and BcBOT2 were shown by quantitative reverse transcription-PCR to be co-regulated through the calcineurin signaling pathway. Inactivation of the BcBOT2 gene, encoding a putative sesquiterpene cyclase, abolished botrydial biosynthesis, which could be restored by in trans complementation. Inactivation of BcBOT2 also resulted in overproduction of botcinic acid that was observed to be strain-dependent. Recombinant BcBOT2 protein converted farnesyl diphosphate to the parent sesquiterpene of the botrydial biosynthetic pathway, the tricyclic alcohol presilphiperfolan-8β-ol.

Carbon nanotube (CNT) materials are of special interest as potential tools for biomedical applications. However, available toxicological data concerning single-walled carbon nanotubes (SWNTs) and multiwalled carbon nanotubes (MWNTs) remain contradictory. Here, we compared the effects of SWNTs as a function of dose, length, and surface chemistry in Swiss mice. Transmission electron microscopy (TEM), Raman, near-infrared (NIR), and X-ray photoelectron spectroscopies have been used to characterize the tested materials. The dose of SWNT materials used in this study is considerably higher than that proposed for most biomedical applications, but it was deemed necessary to administer such large doses to accurately assess the toxicological impact of the materials. In an acute toxicity test, SWNTs were administered orally at a dose level of 1000 mg/kg bodyweight (b.w.). Neither death nor growth or behavioral troubles were observed. After intraperitoneal administration, SWNTs, irrespective of their length or dose (50-1000 mg/kg b.w.), can coalesce inside the body to form fiberlike structures. When structure lengths exceeded 10 mum, they irremediably induced granuloma formation. Smaller aggregates did not induce granuloma formation, but they persisted inside cells for up to 5 months after administration. Short (<300 nm) well-individualized SWNTs can escape the reticuloendothelial system to be excreted through the kidneys and bile ducts. These findings suggest that if the potential of SWNTs for medical applications is to be realized, they should be engineered into discrete, individual "molecule-like" species.

a b s t r a c tBotrydial (BOT) is a non-host specific phytotoxin produced by the polyphagous phytopathogenic fungus Botrytis cinerea. The genomic region of the BOT biosynthetic gene cluster was investigated and revealed two additional genes named Bcbot6 and Bcbot7. Analysis revealed that the G + C/A + T-equilibrated regions that contain the Bcbot genes alternate with A + T-rich regions made of relics of transposable elements that have undergone repeat-induced point mutations (RIP). Furthermore, BcBot6, a Zn(II) 2 Cys 6 putative transcription factor was identified as a nuclear protein and the major positive regulator of BOT biosynthesis. In addition, the phenotype of the DBcbot6 mutant indicated that BcBot6 and therefore BOT are dispensable for the development, pathogenicity and response to abiotic stresses in the B. cinerea strain B05.10. Finally, our data revealed that B. pseudocinerea, that is also polyphagous and lives in sympatry with B. cinerea, lacks the ability to produce BOT. Identification of BcBot6 as the major regulator of BOT synthesis is the first step towards a comprehensive understanding of the complete regulation network of BOT synthesis and of its ecological role in the B. cinerea life cycle.

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Chloride channels play important roles in homeostasis and regulate cell volume, transepithelial transport, and electrical excitability. Despite recent progress made in the genetic and molecular aspect of chloride channels, their pharmacology is still poorly understood. The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated epithelial chloride channel for which mutations cause cystic fibrosis. Here we have synthesized benzo[c]quinolizinium and benzo[f]indolo[2,3-a]quinolizinium salts (MPB) and performed a SAR to identify the structural basis for activation of the CFTR chloride channel. Synthesized compounds were evaluated on wild-type CFTR and on CFTR having the glycine-to-aspartic acid missense mutation at codon 551 (G551D-CFTR), using a robot and cell-based assay. The presence of an hydroxyl group at position 6 of the benzo[c]quinolizinium skeleton associated with a chlorine atom at position 10 or 7 and an alkyl chain at position 5 determined the highest activity. The most potent product is 5-butyl-7-chloro-6-hydroxybenzo[c]quinolizinium chloride (8u, MPB-104). 8u is 100 times more potent than the parent compound 8a (MPB-07).

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This study aimed to determine whether powdery mildew caused by Blumeria graminis is an endemic pathogen of triticale (·Triticosecale: Triticum · Secale), emerging as a result of recent changes in its pathogenicity, or whether it is a new pathogen, possibly resulting from hybridization between ff. spp. tritici and secalis. A secondary aim was to consider breeding practices that may have favoured this emergence. Phylogenetic analyses based upon six genes revealed the close relatedness of the novel entity and the ff. spp. tritici and secalis, but the IGS marker finally grouped together the isolates collected on triticale and on wheat, supporting the scenario of a recent host-range expansion from wheat to triticale. Pathotype analyses concluded that virulence spectra of B. graminis infecting triticale were new in comparison to those observed for other reference formae speciales, and lack of fungicide resistance in triticale isolates strengthens the hypothesis of no or little genetic exchange between wheat and triticale populations of powdery mildew. This adaptation may follow the breakdown of plant resistance genes, which are probably not very diverse in current triticale cultivars since this criterion was not considered as a major one until recent years. Moreover, the complex selection and genetics of this hybrid cereal makes it difficult to predict the transmission of powdery mildew resistance genes.

Angiotensin-converting enzyme (ACE) was measured in serum of 187 healthy children between the ages six months and 18 years. Results were pooled for five-year age intervals and compared with the reference values for adults that we previously determined [Clin Chem 1986;32:884-6). Results for each age group were also studied as a function of sex. Children had higher ACE activities in serum than did adults (P less than 0.001), but these activities were age-related only from age four to 18 years. Adolescents showed sex-related differences, with higher serum ACE activities in boys than in girls (P less than 0.05). Both sex- and age-related differences may be related to a steroid hormonal regulation of ACE biosynthesis. We also verified that children with sarcoidosis (n = 20) had significantly increased serum ACE activity. Such physiological variations in serum ACE activity must be taken into account for diagnosing sarcoidosis in children, for following the course of the disease, and for evaluating the accuracy of therapy.