Detection of fungal metabolites of various Trichoderma species by the aphid Schizaphis graminum

The feeding preferences of alate and apterous morphs of the aphid Schizaphis graminum (Rondani) (Homoptera: Aphididae) were evaluated using leaves treated with powdered rice cultures of four fungal isolates belonging to different species of the genus Trichoderma (Deuteromycotina: Hyphomycetes). All of the fungal isolates restrained alate morphs of S. graminum from visiting treated leaves, but only Trichoderma citrinoviride Bisset also influenced the preference of apterous morphs. Trials carried out with supernatants obtained by centrifuging aqueous suspensions of the fungal cultures showed that the feeding preference of aphids was maintained in the absence of fungal spores and mycelia, supporting the hypothesis that at least part of the fungal metabolites responsible for this effect were water‐soluble compounds. Electrophysiological studies showed that the structures involved in the perception of the fungal metabolites are located on the aphid tarsomeres.     

Assignment of human aldolase C gene to chromosome 17, region cen→q21.1

Summary The mapping of the gene coding for human aldolase C has been studied using a specific cDNA probe and genomic blots from a panel of human-hamster somatic cell hybrids. The results show that the aldolase C gene is on chromosome 17. In situ experiments have restricted the mapping to the region 17cenq21.1. Using the same panel of human-hamster somatic cell hybrids, we have confirmed the localization of aldolase A and B on chromosomes 16 and 9, respectively.     

ATP citrate lyase activity is post‐translationally regulated by sink strength and impacts the wax,cutin and rubber biosynthetic pathways

Cytosolic acetyl‐CoA is involved in the synthesis of a variety of compounds, including waxes, sterols and rubber, and is generated by the ATP citrate lyase (ACL). Plants over‐expressing ACL were generated in an effort to understand the contribution of ACL activity to the carbon flux of acetyl‐CoA to metabolic pathways occurring in the cytosol. Transgenic Arabidopsis plants synthesizing the polyester polyhydroxybutyrate (PHB) from cytosolic acetyl‐CoA have reduced growth and wax content, consistent with a reduction in the availability of cytosolic acetyl‐CoA to endogenous pathways. Increasing the ACL activity via the over‐expression of the ACLA and ACLB subunits reversed the phenotypes associated with PHB synthesis while maintaining polymer synthesis. PHB production by itself was associated with an increase in ACL activity that occurred in the absence of changes in steady‐state mRNA or protein level, indicating a post‐translational regulation of ACL activity in response to sink strength. Over‐expression of ACL in Arabidopsis was associated with a 30% increase in wax on stems, while over‐expression of a chimeric homomeric ACL in the laticifer of roots of dandelion led to a four‐ and two‐fold increase in rubber and triterpene content, respectively. Synthesis of PHB and over‐expression of ACL also changed the amount of the cutin monomer octadecadien‐1,18‐dioic acid, revealing an unsuspected link between cytosolic acetyl‐CoA and cutin biosynthesis. Together, these results reveal the complexity of ACL regulation and its central role in influencing the carbon flux to metabolic pathways using cytosolic acetyl‐CoA, including wax and polyisoprenoids.     

Comparison of bacteriocins production from Enterococcus faecium strains in cheese whey and optimised commercial MRS medium

The production of bacteriocins from cheap substrates could be useful for many food industrial applications. This study aimed at determining the conditions needed for optimal production of enterocins SD1, SD2, SD3 and SD4 secreted by Enterococcus faecium strains SD1, SD2, SD3 and SD4, respectively. To our knowledge, this is the first use of cheese whey—a low-cost milk by-product—as a substrate for bacteriocin production by E. faecium; skimmed milk and MRS broths were used as reference media. This cheese manufacturing residue proved to be a promising substrate for the production of bacteriocins. However, the levels of secreted antimicrobial compounds were lower than those achieved by E. faecium strains in MRS broth. Bacteriocin production was affected strongly by physical and chemical factors such as growth temperature, time of incubation, pH, and the chemical composition of the culture medium. The optimal temperature and time of incubation supporting the highest bacteriocin production was determined for each strain. Different types, sources and amounts of organic nitrogen, sugar, and inorganic salts played an essential role in bacteriocin secretion. E. faecium strains SD1 and SD2—producing high bacteriocin levels both in cheese whey and skimmed milk—could be of great interest for potential applications in cheese-making.     

Effects of the fungus <Emphasis Type="Italic">Lecanicillium lecanii</Emphasis> on survival and reproduction of the aphid <Emphasis Type="Italic">Schizaphis graminum</Emphasis>

This study investigated the effects of a strain of the fungus Lecanicillium lecanii (Zimm.) Zare and Gams (Hypocreales: Ascomycota) on the aphid Schizaphis graminum (Rondani) (Hemiptera: Aphididae). The fungus was administered to fourth instar nymphs and to alate and apterous adult morphs as a ground rice-kernel formulation. This study showed that L. lecanii formulation affected the survival of the aphids and interacted differently with the studied morphs, the Lethal Time values being lower for alate compared to apterous morphs and nymphs. The treatment also caused a significant reduction in the fecundity of the three treated aphid groups. Histological analysis revealed that the hyphae invaded the host hemocoel of a limited number of alate and apterous morphs: the fungus only entered through the spiracles. Scanning Electron Microscope observations revealed that L. lecanii adhered to the body surface of both adults and nymphs without differentiation. In conclusion, the present study suggests that this strain might be a good candidate for a programme of biological control of S. graminum and other aphid species.     

Myosin7a Deficiency Results in Reduced Retinal Activity Which Is Improved by Gene Therapy

Mutations in MYO7A cause autosomal recessive Usher syndrome type IB (USH1B), one of the most frequent conditions that combine severe congenital hearing impairment and retinitis pigmentosa. A promising therapeutic strategy for retinitis pigmentosa is gene therapy, however its pre-clinical development is limited by the mild retinal phenotype of the shaker1 (sh1^−/−) murine model of USH1B which lacks both retinal functional abnormalities and degeneration. Here we report a significant, early-onset delay of sh1^−/− photoreceptor ability to recover from light desensitization as well as a progressive reduction of both b-wave electroretinogram amplitude and light sensitivity, in the absence of significant loss of photoreceptors up to 12 months of age. We additionally show that subretinal delivery to the sh1^−/− retina of AAV vectors encoding the large MYO7A protein results in significant improvement of sh1^−/− photoreceptor and retinal pigment epithelium ultrastructural anomalies which is associated with improvement of recovery from light desensitization. These findings provide new tools to evaluate the efficacy of experimental therapies for USH1B. In addition, although AAV vectors expressing large genes might have limited clinical applications due to their genome heterogeneity, our data show that AAV-mediated MYO7A gene transfer to the sh1^−/− retina is effective.     

Role of mutual interactions in the chemical and thermal stability of nucleophosmin NPM1 domains

Nucleophosmin (NPM1) is a key factor involved in fundamental biological processes. Mutations involving the NPM1 gene are the most frequent molecular alterations in acute myeloid leukemia. Here we report a biophysical characterization of NPM1 and of its domains in order to gain insights into the role that inter-domain interactions plays in the protein stabilization. Thermal denaturation analyses show that the N-terminal domain is endowed with an exceptional thermal stability, as it does not unfold in the investigated temperature range (20–105 °C). This finding is corroborated by chemical denaturation experiments showing that this domain is not significantly affected by the addition of 8 M urea. These results are consistent with the chaperone function of NPM1. In line with literature data, the other folded domain of the NPM1, a 3-helix bundle domain located at the C-terminus, shows a lower stability. Interestingly, the chemical and thermal stability of this latter domain, which embeds natural mutations related to acute myeloid leukemia, is influenced by the presence of other regions of the protein. Small but significant stabilizations of the C-terminal 3-helix bundle are provided by the adjacent unfolded fragment as well as by the rest of the protein.     

Use of Nuclear and Mitochondrial Single Nucleotide Polymorphisms to Characterize English Walnut (Juglans regia L.) Genotypes

English walnut (Juglans regia L.) is the most economically important species, for both food and timber, of the 21 species belonging to the genus Juglans. This study was undertaken to analyze and compare DNA sequences of the mitochondrial cytochrome oxidase subunit II (COX2) and ribosomal DNA (rDNA) genes in the molecular characterization of 30 English walnut genotypes. rDNA sequences revealed the presence of 402 variations, including 101 in 3′ ends of 18S, 21 in internal transcribed spacer 1(ITS1), 170 in ITS2, 30 in 5.8S, and 80 in 5′ ends of 28S regions. Cox2 intron I sequences showed 769 variable positions and GG insertion/deletion at 3′ end regions. Based on single nucleotide polymorphism markers of rDNA and cox2 intron I sequences, an amplification refractory mutation system was used to fingerprint 18 out of 30 walnut genotypes. The findings revealed that the cox2 intron I region, either alone or in conjunction with rDNA, could be used effectively in identifying these walnut genotypes.     

Survey of co-infection by Salmonella and oxyurids in tortoises

ABSTRACT: BACKGROUND: Salmonella spp. and oxyurids are among the most prevalent bacterial and parasitic agents in reptiles. These organisms are routinely isolated in healthy tortoises, although heavy infections may cause significant pathology. Tortoises are considered a common source of reptileassociated salmonellosis, an important zoonosis reported worldwide. A survey of the prevalence of almonella spp. and oxyurids in 53 tortoises was conducted in southern Italy and a possible correlation between the two pathogens was therefore investigated. RESULTS: Salmonella spp. and oxyurids were detected with a prevalence of 49.1 and 81.1%, respectively. A significant positive correlation between Salmonella spp. and oxyurids was demonstrated. However, confounding factors related to husbandry could have been involved in determining this correlation. CONCLUSIONS: Our results suggest that caution should be exercised in translocation, husbandry, and human contact with tortoises and other exotic pets. Further studies on the epidemiology, molecular characterization and pathogenesis of Salmonella and oxyurids are needed to assess the actual impact of these organisms, as single or associated infections, on tortoises and on other exotic pets.