Ewes from the Booroola strain of Australian Mé rino sheep are characterized by high ovulation rate and litter size. This phenotype is due to the action of the FecB B allele of a major gene named FecB, as determined by statistical analysis of phenotypic data. By genetic analysis of 31 informative half-sib families from heterozygous sires, we showed that the FecB locus is situated in the region of ovine chromosome 6 corresponding to the human chromosome 4q22-23 that contains the bone morphogenetic protein receptor IB (BMPR-IB) gene encoding a member of the transforming growth factor-␤ (TGF-␤) receptor family. A nonconservative substitution (Q249R) in the BMPR-IB coding sequence was found to be associated fully with the hyperprolificacy phenotype of Booroola ewes. In vitro, ovarian granulosa cells from FecB B ͞FecB B ewes were less responsive than granulosa cells from FecB ؉ ͞FecB ؉ ewes to the inhibitory effect on steroidogenesis of GDF-5 and BMP-4, natural ligands of BMPR-IB. It is suggested that in FecB B ͞FecB B ewes, BMPR-IB would be inactivated partially, leading to an advanced differentiation of granulosa cells and an advanced maturation of ovulatory follicles.

No abstract

No abstract

Escherichia coli LR05, in addition to producing MccB17, J25, and D93, secretes microcin L, a newly discovered microcin that exhibits strong antibacterial activity against related Enterobacteriaceae, including Salmonella enterica serovars Typhimurium and Enteritidis. Microcin L was purified using a two-step procedure including solid-phase extraction and reverse-phase C 18 high-performance liquid chromatography. A 4,901-bp region of the DNA plasmid of E. coli LR05 was sequenced revealing that the microcin L cluster consists of four genes, mclC, mclI, mclA, and mclB. As bacterial resistance to currently used antibiotics is increasing, new pathogenic agents are discovered, and traditional bacterial diseases reappear, increased efforts to search for new antibiotics are needed. Over the past 40 years, research has been restricted largely to improving those well-known compound classes that are active against a standard set of drug targets. As no new classes of antibiotic have been discovered, such insufficient chemical variability exists that there is a potential for serious escalation in clinical microbe resistance. Numerous living organisms are able to produce a variety of ribosomally synthesized antibacterial peptides or proteins involved in their innate defense against microorganisms. During the past 15 years, these compounds have attracted considerable attention, offering many exciting possibilities for the future of antibiotics, in the face of current declining efficacy of conventional treatment (20,22). Of the bacteriocins produced by bacteria, many direct activity against pathogens and, in particular, food-borne microorganisms, such as the grampositive bacterium Listeria monocytogenes (7, 10) and gramnegative bacteria Salmonella enterica and Escherichia coli (34,40).Microcins are secreted by members of the Enterobacteriaceae family, in particular strains of E. coli. They constitute a class of low-molecular-mass peptides (Ͻ10 kDa) that exhibit a narrow antimicrobial spectrum of activity directed against bacterial species phylogenetically related to the producing strains (33). To protect itself, the microcin-producing bacterium exhibits immunity to the action of its own microcin. Recent developments in the biochemical characterization and mode of action allowed us to propose a classification of these peptides into two classes (17, 36). Class I, which includes to date microcins B17, C7, D93, and J25, encompasses peptides with molecular mass below 5 kDa that are highly posttranslationally modified. These microcins display a range of unrelated chemical structures, which in turn results in a variety of action mechanisms (9). Class II includes microcins E492, H47, V, most likely microcin 24, and now microcin L. This second group is more homogeneous and shares several common structural properties with class IIa gram-positive bacteriocins: size ranging from 7 to 10 kDa, absence of modified amino acids, and presence of a consensus motif. Additionally, they are synthesized as precursor peptides with a double-glycine type ...

Direct amplification of length polymorphisms (DALP) uses an arbitrarily primed PCR (AP-PCR) to produce genomic fingerprints and to enable sequencing of DNA polymorphisms in virtually any species. Oligonucleotide pairs were designed to each produce a specific multi-banded pattern and all the fragments thus generated can be directly sequenced with the same two universal M13 sequencing primers. This strategy combines the advantages of a high resolution fingerprint technique and the possibility of characterizing the polymorphisms. The use of family members as templates in the multi-locus detection step allows a direct test of allele transmission, as well as early mapping of the markers or selection of loci associated with some traits or diseases. We used this method to detect micro-deletions/insertions and microsatellite DNA loci useful in population genetics studies, but it could be applied in many other fields of biology, such as genome mapping for definition of polymorphic sequence tagged sites, directly localized on a genetic map.

Dunaliella tertiolecta (DT) was chemically investigated to isolate molecules inhibiting cancer cell proliferation and inducing apoptosis in vitro. The potency to inhibit cell growth was used for the bio-guided fractionation and isolation of active compounds using chromatographic techniques. The DT dichloromethane extract exhibited a strong anti-proliferative activity on MCF-7 and LNCaP cells, and was further fractionated and sub-fractionated by RP-HPLC. High resolution mass spectrometry and spectrophotometric analysis unequivocally identified violaxanthin as the most antiproliferative molecule present in DT DCM extract. Violaxanthin purified from DT induced MCF-7 dose-dependent growth inhibition in continuous and discontinuous treatments, at concentrations as low as 0.1 μg·mL−1 (0.17 μM). Phosphatidylserine exposure, typical of early apoptosis, was observed after 48 h treatment at 8 μg·mL−1 (13.3 μM) but no DNA fragmentation, characteristic of late apoptosis steps, could be detected even after 72 h treatment at 40 μg·mL−1 (66.7 μM). Taken together, our results demonstrate the strong antiproliferative activity of violaxanthin on one human mammary cancer cell line, and suggest that studying the pharmacology of violaxanthin and pharmacomodulated derivatives on cancer cells may allow potent antiproliferative drugs to be obtained.

No abstract

No abstract