Sugar beet leaves as new source of hydroperoxide lyase in a bioprocess producing green-note aldehydes

Hydroperoxide lyase activity was found in sugar beet leaves. Its optimum pH and temperature were, respectively, 6.7 and 22°C. Under these conditions, conversion of linolenic acid 13-hydroperoxide to cis-3-hexenal with a maximum yield of 80% was reached after only 2 min. The stability of cis-3-hexenal was improved by acidifying the reaction medium. Based on these studies, a bioprocess producing green-note aldehydes in a laboratory-scale was achieved. The authors Holy N. Rabetafika and Cédric Gigot contributed equally.     

Potato tuber phospholipids contain colneleic acid in the 2-position

Colneleic acid (9-[1'(E),3'(Z)-nonadienyloxy]-8(E)-nonenoic acid) is produced from linoleic acid by the sequential action of 9-lipoxygenase and divinyl ether synthase. We demonstrate that a small fraction of the colneleic acid in potato tubers is esterified in phospholipids. This colneleic acid was released by chemical hydrolysis and a phospholipase A(2), but not by a lipase with 1-acyl specificity. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol contain molecular species with nominal masses consistent with identification as palmitoyl,colneleoyl species. Exact mass analysis of its fragments confirmed the identity of palmitoyl,colneloyl phosphatidylinositol. To our knowledge, this work represents the first identification of a colneleoyl phospholipid.     

Synthesis of 3-C-(6-O-acetyl-2,3,4-tri-O-benzyl-alpha-D-mannopyranosyl)-1-propene: a caveat

During the preparation of 3-C-(6-O-acetyl-2,3,4-tri-O-benzyl-alpha-D-mannopyranosyl)-1-propene, using a published Sakurai-type reaction on the parent methyl glycoside, some observations were made on the sensitivity to reaction conditions that were not previously reported. This Note presents the study of this allylation reaction followed by acetolysis, which ultimately led to the best conditions to obtain the C-glycoside, and on further transformations to yield the corresponding aldehydic and acidic derivatives.     

GnRH deficiency: new insights from genetics

The acquisition of a sexually dimorphic phenotype is a critical event in mammalian development. Hypogonadotropic hypogonadism (HH) results from impaired secretion of GnRH. The patients display with delayed puberty, micropenis and cryptorchidism in the male reflecting gonadotropin insufficiency, and amenorrhea in the female. Kallmann's syndrome (KS) is defined by the association of HH and anosmia or hyposmia (absent smelling sense). Segregation analysis in familial cases has demonstrated diverse inheritance patterns, suggesting the existence of several genes regulating GnRH secretion. The X-linked form of the disease was associated with a genetic defect in the KALI gene located on the Xp22.3 region. KAL1 gene encodes an extracellular matrix glycoprotein anosmin-1, which facilitates neuronal growth and migration. Abnormalities in the migratory processes of the GnRH neurons with the olfactory neurons explain the association of HH with anosmia. Recently, mutations in the FGF recepteur 1 (FGFR1) gene were found in KS with autosomal dominant mode of inheritance. The role of FGFR1 in the function of reproduction requires further investigation. Besides HH with anosmia, there are isolated HH (IHH). No human GnRH mutations have been reported although hypogonadal mice due to a GnRH gene deletion exist. In patients with idiopathic HH and without anosmia an increasing number of GnRH receptor (GnRHR) mutations have been described which represent about 50% of familial cases. The clinical features are highly variable and there is a good relationship between genotype and phenotype. A complete loss of function is associated with the most severe phenotype with resistance to pulsatile GnRH treatment, absence of puberty and cryptorchidism in the male. In contrast, milder loss of function mutations causes incomplete failure of pubertal development. The preponderant role of GnRH in the secretion of LH by the gonadotrophs explains the difference of the phenotype between male and female with partial GnRH resistance. Affected females can have spontaneous telarche and normal breast development while affected males exhibit no pubertal development but normal testis volume, a feature described as "fertile-eunuch". High-dose pulsatile GnRH has been used to induce ovulation. Another gene, called GPR54, responsible for idiopathic HH has been recently described by segregation analysis in two different consanguineous families. The GPR54 gene is an orphan receptor, and its putative ligand is the product of the KISS-1 gene, called metastine. Their roles in the function of reproduction are still unknown.     

One-step, non-denaturing purification method of carp (Cyprinus carpio) vitellogenin

A new single-step purification procedure was developed to purify carp (Cyprinus carpio) vitellogenin (VTG), from estradiol-treated carp plasma. This method was performed by high performance liquid weak anion-exchange chromatography, using a discontinuous elution gradient of NaCl (0-0.5 M, steps of 12.5 mM/4 min). SDS and native-PAGE analysis, of treated-fish plasma and purified solution, showed the appearance of a 370 kDa phospholipoprotein, composed of two 130 kDa monomers, with all VTG characteristics. The sequencing of a 130 kDa monomer confirmed that it was carp VTG. Consequently, this procedure is a rapid method, permitting high quantities of non-denatured carp VTG to be obtained.     

Multiple antimicrobial resistance in plague: an emerging public health risk

Antimicrobial resistance in Yersinia pestis is rare, yet constitutes a significant international public health and biodefense threat. In 1995, the first multidrug resistant (MDR) isolate of Y. pestis (strain IP275) was identified, and was shown to contain a self-transmissible plasmid (pIP1202) that conferred resistance to many of the antimicrobials recommended for plague treatment and prophylaxis. Comparative analysis of the DNA sequence of Y. pestis plasmid pIP1202 revealed a near identical IncA/C plasmid backbone that is shared by MDR plasmids isolated from Salmonella enterica serotype Newport SL254 and the fish pathogen Yersinia ruckeri YR71. The high degree of sequence identity and gene synteny between the plasmid backbones suggests recent acquisition of these plasmids from a common ancestor. In addition, the Y. pestis pIP1202-like plasmid backbone was detected in numerous MDR enterobacterial pathogens isolated from retail meat samples collected between 2002 and 2005 in the United States. Plasmid-positive strains were isolated from beef, chicken, turkey and pork, and were found in samples from the following states: California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, New York and Oregon. Our studies reveal that this common plasmid backbone is broadly disseminated among MDR zoonotic pathogens associated with agriculture. This reservoir of mobile resistance determinants has the potential to disseminate to Y. pestis and other human and zoonotic bacterial pathogens and therefore represents a significant public health concern.