Antifungal activity of Lactobacillus against Microsporum canis, Microsporum gypseum and Epidermophyton floccosum

A total of 220 lactic acid bacteria isolates were screened for antifungal activity using Aspergillus fumigatus and Aspergillus niger as the target strains. Four Lactobacillus strains exhibited strong inhibitory activity on agar surfaces. All four were also identified as having strong inhibitory activity against the human pathogenic fungi Microsporum canis, Microsporum gypseum and Epidermophyton floccosum. One of the four lactobacilli, namely Lb. reuteri ee1p exhibited the most inhibition against dermatophytes. Cell-free culture supernatants of Lb. reuteri ee1p and of the non-antifungal Lb. reuteri M13 were freeze-dried and used to access and compare antifungal activity in agar plate assays and microtiter plate assays. Addition of the Lb. reuteri ee1p freeze-dried cell-free supernatant powder into the agar medium at concentrations greater than 2% inhibited all fungal colony growth. Addition of the powder at 5% to liquid cultures caused complete inhibition of fungal growth on the basis of turbidity. Freeze-dried supernatant of the non-antifungal Lb. reuteri M13 at the same concentrations had a much lesser effect. As Lb. reuteri M13 is very similar to the antifungal strain ee1p in terms of growth rate and final pH in liquid culture, and as it has little antifungal activity, it is clear that other antifungal compounds must be specifically produced (or produced at higher levels) by the anti-dermatophyte strain Lb. reuteri ee1p. Reuterin was undetectable in all four antifungal strains. The cell free supernatant of Lb. reuteri ee1p was analyzed by LC-FTMS using an Accela LC coupled to an LTQ Orbitrap XL mass spectrometer. The high mass accuracy spectrum produced by compounds in the Lb. reuteri ee1p strain was compared with both a multianalyte chromatogram and individual spectra of standard anti-fungal compounds, which are known to be produced by lactic acid bacteria. Ten antifungal metabolites were detected.     

Effects of cereal β-glucans and enzyme inclusion on the porcine gastrointestinal tract microbiota

This study was designed to evaluate the effect barley-based diets vs. oats based diets on levels of Lactobacillus, Bifidobacterium and Enterobacterium in the porcine gastrointestinal tract (GIT). In addition the effect of enzyme supplementation in both diets was explored. Twenty-eight boars were used in a 2 × 2 factorial arrangement and were assigned to 1 of 4 dietary treatments: barley-based (B) diet; barley-based diet plus an enzyme supplement (B + ES); oat-based (O) diet or oat-based diet plus an enzyme supplement (O + ES). The enzyme supplement contained endo-1,3-β-glucanase and endo-1,4-β-xylanase. Faecal samples were collected from the pigs prior to initiations of the experiment and at slaughter. At slaughter digesta samples were collected from the stomach, ileum, caecum, proximal and distal colon. Alterations in Lactobacillus species composition in the gastrointestinal tract (GIT) were analysed by genus-specific PCR – denaturing gradient gel electrophoresis (DGGE). DGGE profiles indicated that cereal source provoked shifts in Lactobacillus population. The most diverse populations of lactobacilli emerged after feeding the O diets. Enzymes inclusion altered the composition of Lactobacillus species prevalent throughout the GIT in animals fed the B diet, causing a shift in the dominant lactobacilli present in the caecum and proximal colon. No such effect was evident in animals fed the enzyme supplemented O + ES diet. Microbial plate counts revealed that the O diets gave rise to higher counts of Lactobacillus in the caecum and colon and Bifidobacterium counts in the ileum, caecum and colon than the B diets. The O diet caused a 2 log increase in Enterobacterium counts in the proximal colon, no such effects were observed in animals fed the B, the B + ES or the O + ES diets. Overall both O diets had a more positive influence on the counts of the beneficial microorganisms and richness of the Lactobacillus population in the porcine GIT.     

Attributes of short linear motifs

Traditionally, protein-protein interactions were thought to be mediated by large, structured domains. However, it has become clear that the interactome comprises a wide range of binding interfaces with varying degrees of flexibility, ranging from rigid globular domains to disordered regions that natively lack structure. Enrichment for disorder in highly connected hub proteins and its correlation with organism complexity hint at the functional importance of disordered regions. Nevertheless, they have not yet been extensively characterised. Shifting the attention from globular domains to disordered regions of the proteome might bring us closer to elucidating the dense and complex connectivity of the interactome. An important class of disordered interfaces are the compact mono-partite, short linear motifs (SLiMs, or eukaryotic linear motifs (ELMs)). They are evolutionarily plastic and interact with relatively low affinity due to the limited number of residues that make direct contact with the binding partner. These features confer to SLiMs the ability to evolve convergently and mediate transient interactions, which is imperative to network evolution and to maintain robust cell signalling, respectively. The ability to discriminate biologically relevant SLiMs by means of different attributes will improve our understanding of the complexity of the interactome and aid development of bioinformatics tools for motif discovery. In this paper, the curated instances currently available in the Eukaryotic Linear Motif (ELM) database are analysed to provide a clear overview of the defining attributes of SLiMs. These analyses suggest that functional SLiMs have higher levels of conservation than their surrounding residues, frequently evolve convergently, preferentially occur in disordered regions and often form a secondary structure when bound to their interaction partner. These results advocate searching for small groupings of residues in disordered regions with higher relative conservation and a propensity to form the secondary structure. Finally, the most interesting conclusions are examined in regard to their functional consequences.     

Interactions between the hemiparasitic angiospermRhinanthus minor and its hosts: From the cell to the ecosystem

Parasitic plants can significantly influence the species to which they attach. The host response is variable however, and ranges from death of the host to no detectable effects in terms of both growth and physiology. The parasite can directly influence its hosts through resource abstraction, and indirectly by influencing inter- and intra-specific interactions. Abiotic factors interact with these direct and indirect effects to moderate the potential outcome of the host parasite interaction. This paper sets out to review a series of experiments that have been undertaken in our laboratory over a number of years that examine these effects and help us to understand mechanisms underpinning the variability in host response.     

Molecular determinants of high affinity binding to group III metabotropic glutamate receptors.

The amino-terminal domain containing the ligand binding site of the G protein-coupled metabotropic glutamate receptors (mGluRs) consists of two lobes that close upon agonist binding. In this study, we explored the ligand binding pocket of the Group III mGluR4 receptor subtype using site-directed mutagenesis and radioligand binding. The selection of 16 mutations was guided by a molecular model of mGluR4, which was based on the crystal structure of the mGluR1 receptor. Lysines 74 and 405 are present on lobe I of mGluR4. The mutation of lysine 405 to alanine virtually eliminated the binding of the agonist [(3)H]l-amino-4-phosphonobutyrate ([(3)H]l-AP4). Thus lysine 405, which is conserved in all eight mGluRs, likely represents a fundamental recognition residue for ligand binding to the mGluRs. Single point mutations of lysines 74 or 317, which are not conserved in the mGluRs, to alanine had no effect on agonist affinity, whereas mutation of both residues together caused a loss of ligand binding. Mutation of lysine 74 in mGluR4, or the analogous lysine in mGluR8, to tyrosine (mimicking mGluR1 at this position) produced a large decrease in binding. The reduction in binding is likely due to steric hindrance of the phenolic side chain of tyrosine. The mutation of glutamate 287 to alanine, which is present on lobe II and is not conserved in the mGluR family, caused a loss of [(3)H]l-AP4 binding. We conclude that the determinants of high affinity ligand binding are dispersed across lobes I and II. Our results define a microenvironment within the binding pocket that encompasses several positively charged amino acids that recognize the negatively charged phosphonate group of l-AP4 or the endogenous compound l-serine-O-phosphate.     

Enhancing the biodiversity of Scotland's forest resource through the development of a network of forest habitats

Scottish Natural Heritage, the statutory conservation agency, is considering the desirability and feasibility of developing a network of woodland habitats to redress the long term trend of fragmentation and isolation. Woodland conservation has long been based on site protection, but recent changes in policy, attitude and practice have opened up the possibility of recreating native forest cover on a much larger scale. The ECONET approach appears to have much to offer as the basis for enhancing the biodiversity of Scotland's forest resource. A network could be developed from existing woods to form a Scotland-wide network of Core Forest Areas and major landscape links, largely associated with major valleys. To achieve this, existing concentrations of woodland would be extended into poorly wooded districts. Many vulnerable wildlife species are likely to benefit, and there would be other benefits for recreation, landscape and timber production.     

Gender Differentiated Preferences for a Community-Based Conservation Initiative

Community-based conservation (CBC) aims to benefit local people as well as to achieve conservation goals, but has been criticised for taking a simplistic view of “community” and failing to recognise differences in the preferences and motivations of community members. We explore this heterogeneity in the context of Kenya’s conservancies, focussing on the livelihood preferences of men and women living adjacent to the Maasai Mara National Reserve. Using a discrete choice experiment we quantify the preferences of local community members for key components of their livelihoods and conservancy design, differentiating between men and women and existing conservancy members and non-members. While Maasai preference for pastoralism remains strong, non-livestock-based livelihood activities are also highly valued and there was substantial differentiation in preferences between individuals. Involvement with conservancies was generally perceived to be positive, but only if households were able to retain some land for other purposes. Women placed greater value on conservancy membership, but substantially less value on wage income, while existing conservancy members valued both conservancy membership and livestock more highly than did non-members. Our findings suggest that conservancies can make a positive contribution to livelihoods, but care must be taken to ensure that they do not unintentionally disadvantage any groups. We argue that conservation should pay greater attention to individual-level differences in preferences when designing interventions in order to achieve fairer and more sustainable outcomes for members of local communities.