Farnesylacetone, a sesquiterpenic hormone of Crustacea, inhibits electron transport in isolated rat liver mitochondria

Farnesylacetone (C18 H30 0) is a male hormone extracted from the androgenic gland of crab, Carcinus maenas. Appropriate enzymatic assays, as well as spectrophotometric studies, indicate that micromolar concentrations of farnesylacetone interact with the electron transport pathway of rat liver mitochondria. By the use of artificial electron donors and electron acceptors, it is shown that farnesylacetone immediately inhibits the electron transfer within complex I (NADH ubiquinone reductase activity) and complex II (succinate ubiquinone reductase activity). It is proposed that farneylacetone could interact with these two complexes of the respiratory chain at the level of the iron-sulfur centers implicated in the dehydrogenase activities. These observations are compared with the results obtained with terpenic molecules which interact with mitochondrial respiration.     

Site-specific integration of plasmid pSAM2 in Streptomyces lividans and S. ambofaciens

Summary Streptomyces ambofaciens strain ATCC23877 contains the 11.1 kb plasmid pSAM2 stably integrated into its chromosome. This plasmidic sequence is able to loop out and to be transferred at high frequency to S. lividans where it is found simultaneously as both free and integrated plasmid. When a UV derivative of strain ATCC23877 (strain ATCC15154) is used, the resident copy of pSAM2 can be transferred to S. lividans, but only the integrated form is found in this strain. In both cases, the integration occurs at a unique chromosomal region through the same plasmidic integration site as that in strain ATCC23877. The resident copy of strain ATCC15154 can also be transferred at low frequency to S. ambofaciens DSM40697 (devoid of any pSAM2 sequence). In this case, as several copies of pSAM2 are integrated, the integration pattern is complicated. Integration of a complete pSAM2 sequence in this strain occurs in a region that hybridizes with the integration zones of S. lividans and of S. ambofaciens strain ATCC23877. Comparison of the cloned integration zone of S. lividans before and after the integration event showed that the restriction pattern of the resident pSAM2 in strain ATCC15154 is similar to that of the free form of pSAM2 found naturally in another UV derivative of strain ATCC23877 (strain JI3212).     

A 2.6 kb intron separates the signal peptide coding sequence of an anther-specific protein from the rest of the gene in sunflower

Summary Metabolism of sulfonylurea herbicides by Streptomyces griseolus ATCC 11796 is carried out via two cytochromes P-450, P-450_SU1 and P-450_SU2. Mutants of S. griseolus, selected by their reduced ability to metabolize a fluorescent sulfonylurea, do not synthesize cytochrome P-450_SU1 when grown in the presence of sulfonylureas. Genetic evidence indicated that this phenotype was the result of a deletion of > 15 kb of DNA, including the structural genes for cytochrome P-450_SU1 and an associated ferredoxin Fd-1 (suaC and suaB, respectively). In the absence of this monooxygenase system, the mutants described here respond to the presence of sulfonylureas or phenobarbital in the growth medium with the expression of only the suhC,B gene products (cytochrome P-450_SU2 and Fd-2), previously observed only as minor components in wild-type cells treated with sulfonylurea. These strains have enabled an analysis of sulfonylurea metabolism mediated by cytochrome P-450_SU2 in the absence of P-450_SU1, yielding an in vivo delineation of the roles of the two different cytochrome P-450 systems in herbicide metabolism by S. griseolus.     

Anther-specific,developmentally regulated expression of genes encoding a new class of proline-rich proteins in sunflower

We have used RNA gel blot analysis to demonstrate the anther-specific expression of three genes in sunflower. Expression of these genes was first detected shortly before flower opening, which occurs sequentially on the sunflower inflorescence, and continues during pollination. In contrast, these genes are not expressed (or only weakly expressed) in a male-sterile line in which anther development aborts. In situ hybridization experiments showed that these genes are only expressed in the single cell layer of the sunflower anther epidermis. In the case of one of these genes, which codes for an abundant mRNA, we report the peptide sequences deduced from the sequence of two similar but non identical cDNAs. These proteins contain a potential signal peptide and are characterized by the presence of a proline-rich region which reads KPSTPAPPPPPP(PP)K. Our results also suggest that several proline-rich proteins of unknown functions are specifically synthesized during the maturation of anthers in sunflower.     

Inhibition of bilirubin UDPglucuronosyltransferase activity by triphenylacetic acid and related compounds

Bilirubin UDPglucuronosyltransferase of rat or human liver microsomes was inhibited, in vitro, by triphenylacetic acid and by structurally related arylcarboxylic acids. This inhibition appeared to be competitive towards bilirubin, and mixed-type towards UDPglucuronic acid. A decrease in the number of phenyl rings or the absence of the carboxyl group in the molecule gave structures which did not affect enzyme activity, showing that both the triphenyl moiety and the carboxyl group were necessary for the inhibition. On the other hand, successive additions of methylene groups in the aliphatic chain progressively increased inhibitory potency. Kappi,bilirubin for triphenylacetic acid was 96 microM compared with 5 microM for 7,7,7-triphenylheptanoic acid. The inhibition of bilirubin UDPglucuronosyltransferase was not due to displacement of bilirubin from albumin. On the basis of these results an attempt was made to delineate the molecular events leading to glucuronidation of bilirubin.     

Cell population obtained by bronchoalveolar lavage in Pneumocystis carinii pneumonitis

In the course of bronchoalveolar lavages performed in 115 immunocompromised patients in order to investigate the occurrences of pneumonitis, Pneumocystis carinii pneumonia was diagnosed by demonstration of cysts in bronchoalveolar lavage specimens from 11 patients. The cellular phenomena associated with P. carinii infection at the level of the alveolar space were evaluated. Differential cell counts on bronchoalveolar lavage preparations stained by the May-Grünwald-Giemsa method were performed in immunocompromised patients and in ten nonimmunocompromised patients without any respiratory disease. A decrease in the alveolar macrophage count associated with an increase in the polymorphonuclear neutrophil count and the presence of plasma cells and/or immunoblasts was highly suggestive of P. carinii pneumonia. These cellular changes in bronchoalveolar lavage specimens are discussed in relation to the pathologic features usually described in P. carinii pneumonia.     

Differentiation of the rat epididymis after withdrawal of androgen

Summary The differentiation capacity of the rat epididymis after depletion of androgen was studied in organ culture and in castrated rats. The differentiation of narrow cells in 5- and 10-day-old explants and in 10-day-old castrated rats suggests that: (i) the testicular androgens are not essential for their differentiation, (ii) a differential androgen dependence exists among the epididymal cell types, (iii) the undifferentiated epithelial cells are the precursors of the narrow cells.     

Occurrence of Lactic Acid Bacteria During the Different Stages of Vinification and Conservation of Wines

We showed that the growth of lactic acid bacteria during alcoholic fermentation depends on the composition of the must. We illustrated how the addition of sulfur dioxide to the must before fermentation and the temperature of storage both affect the growth of these bacteria in the wine. Whereas species of Lactobacillus and Leuconostoc mesenteroides were isolated from grapes and must, Leuconostoc oenos was the only species isolated after alcoholic fermentation. This organism was responsible for the malolactic fermentation. Isolates of this species varied in their ability to ferment pentoses and hexoses. The survival of Leuconostoc oenos in wines after malolactic fermentation depended on wine pH, alcohol concentration, SO₂ concentration, and temperature of storage.