An exotic parasitoid provides an invasional lifeline for native parasitoids

The introduction of an exotic species may alter food webs within the ecosystem and significantly affect the biodiversity of indigenous species at different trophic levels. It has been postulated that recent introduction of the brown marmorated stinkbug (Halyomorpha halys (Stål)) represents an evolutionary trap for native parasitoids, as they accept H. halys egg masses as a host but produce no viable progeny. Interspecific interactions between European egg parasitoid, Trissolcus cultratus (Mayr), and an Asian parasitoid, Trissolcus japonicus (Ashmead), were assessed by providing egg masses to T. cultratus at various time intervals following the initial parasitization by T. japonicus. The suitability of the host for the parasitoid development was re‐assessed by providing T. cultratus with fresh and frozen egg masses of various ages. The likelihood of T. cultratus being able to attack previously parasitized egg masses was determined by assessing the duration of egg mass guarding behavior by T. japonicus following parasitization. The results of experiments examining the interspecific interactions between a native European egg parasitoid, T. cultratus, and an Asian parasitoid, T. japonicus (a candidate for the biological control of H. halys), showed that the native species can act as facultative hyperparasitoid of the exotic one. Although this is only possible during certain stages of T. japonicus development, the presence of the introduced parasitoid may reduce the impact of the evolutionary trap for indigenous parasitoid species. There is a possibility that the occurrence of facultative hyperparasitism between scelionid parasitoids associated with stinkbugs is common. This resulting intraguild predation could promote conservation and stabilization of natural communities by impacting the diversity and population dynamics of native stinkbugs and their parasitoids (e.g., by allowing native parasitoids to avoid wasting reproductive effort on unsuitable hosts), or reduce success of biological control programs (e.g., by reducing the population size of the exotic parasitoids).     

High intraspecific diversity of Restorer‐of‐fertility‐like genes in barley

Nuclear restorer of fertility (Rf) genes suppress the effects of mitochondrial genes causing cytoplasmic male sterility (CMS), a condition in which plants fail to produce viable pollen. Rf genes, many of which encode RNA‐binding pentatricopeptide repeat (PPR) proteins, are applied in hybrid breeding to overcome CMS used to block self‐pollination of the seed parent. Here, we characterise the repertoire of restorer‐of‐fertility‐like (RFL) PPR genes in barley (Hordeum vulgare). We found 26 RFL genes in the reference genome (‘Morex’) and an additional 51 putative orthogroups (POGs) in a re‐sequencing data set from 262 barley genotypes and landraces. Whereas the sequences of some POGs are highly conserved across hundreds of barley accessions, the sequences of others are much more variable. High sequence variation strongly correlates with genomic location – the most variable genes are found in a cluster on chromosome 1H. A much higher likelihood of diversifying selection was found for genes within this cluster than for genes present as singlets. This work includes a comprehensive analysis of the patterns of intraspecific variation of RFL genes. The RFL sequences characterised in this study will be useful for the development of new markers for fertility restoration loci.     

Use of 16S rRNA Gene for Identification of a Broad Range of Clinically Relevant Bacterial Pathogens

According to World Health Organization statistics of 2011, infectious diseases remain in the top five causes of mortality worldwide. However, despite sophisticated research tools for microbial detection, rapid and accurate molecular diagnostics for identification of infection in humans have not been extensively adopted. Time-consuming culture-based methods remain to the forefront of clinical microbial detection. The 16S rRNA gene, a molecular marker for identification of bacterial species, is ubiquitous to members of this domain and, thanks to ever-expanding databases of sequence information, a useful tool for bacterial identification. In this study, we assembled an extensive repository of clinical isolates (n = 617), representing 30 medically important pathogenic species and originally identified using traditional culture-based or non-16S molecular methods. This strain repository was used to systematically evaluate the ability of 16S rRNA for species level identification. To enable the most accurate species level classification based on the paucity of sequence data accumulated in public databases, we built a Naïve Bayes classifier representing a diverse set of high-quality sequences from medically important bacterial organisms. We show that for species identification, a model-based approach is superior to an alignment based method. Overall, between 16S gene based and clinical identities, our study shows a genus-level concordance rate of 96% and a species-level concordance rate of 87.5%. We point to multiple cases of probable clinical misidentification with traditional culture based identification across a wide range of gram-negative rods and gram-positive cocci as well as common gram-negative cocci.     

Glycoprotein hypersecretion alters the cell wall in Trichoderma reesei strains expressing the Saccharomyces cerevisiae dolichylphosphate mannose synthase gene

Expression of the Saccharomyces cerevisiae DPM1 gene (coding for dolichylphosphate mannose synthase) in Trichoderma reesei (Hypocrea jecorina) increases the intensity of protein glycosylation and secretion and causes ultrastructural changes in the fungal cell wall. In the present work, we undertook further biochemical and morphological characterization of the DPM1-expressing T. reesei strains. We established that the carbohydrate composition of the fungal cell wall was altered with an increased amount of N-acetylglucosamine, suggesting an increase in chitin content. Calcofluor white staining followed by fluorescence microscopy indicated changes in chitin distribution. Moreover, we also observed a decreased concentration of mannose and alkali-soluble beta-(1,6) glucan. A comparison of protein secretion from protoplasts with that from mycelia showed that the cell wall created a barrier for secretion in the DPM1 transformants. We also discuss the relationships between the observed changes in the cell wall, increased protein glycosylation, and the greater secretory capacity of T. reesei strains expressing the yeast DPM1 gene.     

TWO DIFFERENT SPECIES OF EUGLENA,E. GENICULATA AND E. MYXOCYLINDRACEA (EUGLENOPHYCEAE), ARE VIRTUALLY GENETICALLY AND MORPHOLOGICALLY IDENTICAL1

We investigated the similarity of a single Euglena myxocylindracea strain, isolated originally by Bold and MacEntee, to several Euglena geniculata strains on both morphological and DNA levels. We found the three DNA stretches, consisting of fragments coding for the parts of cytoplasmic and chloroplast small subunit rRNA, and the internal transcribed spacer (ITS2) of cytoplasmic rDNA, with the combined length of 4332 nucleotides, are identical in E. myxocylindracea and E. geniculata, strain SAG 1224‐4b. Morphological differences between E. myxocylindracea and any E. geniculata strain examined were well within the range of E. geniculata variability as well. The only difference behind the distinction of E. myxocylindracea from E. geniculata is the presence of the second chloroplast in the latter. However, we were able to induce the appearance of the second chloroplast in the cells of E. myxocylindracea and its disappearance in the cells of E. geniculata by changing the composition of the culture media. We therefore conclude that E. myxocylindracea Bold and MacEntee should be regarded as an environmental form of E. geniculata Dujardin. For the first time the morphology of E. geniculata chloroplasts was shown as revealed by confocal laser microscopy.     

Preserving avian blood and DNA sampled in the wild: A survey of personal experiences

Collecting and storing biological material from wild animals in a way that does not deteriorate DNA quality for subsequent analyses is instrumental for research in ecology and evolution. Our aims were to gather reports on the effectiveness of methods commonly used by researchers for the field collection and long‐term storage of blood samples and DNA extracts from wild birds. Personal experiences were collected with an online survey targeted specifically at researchers sampling wild birds. Many researchers experienced problems with blood sample storage but not with DNA extract storage. Storage issues generated problems with obtaining adequate DNA quality and sufficient DNA quantity for the targeted molecular analyses but were not related to season of blood sampling, access to equipment, transporting samples, temperature, and method of blood storage. Final DNA quality and quantity were also not affected by storage time before DNA extraction or the methods used to extract DNA. We discuss practical aspects of field collection and storage and provide some general recommendations, with a list of pros and cons of different preservation methods of avian blood samples and DNA extracts.     

A Convenient Approach to N-3 Alkylation of 9-Substituted Guanines

Abstract

Aryl or tert-butyl substituent in the 6 position of 3,9-dihydro-3-[(2-hydroxy-ethoxy)methyl]-9-oxo-6-R-5H-imidazo[1,2-α]purine 1 directs the benzylation reaction partly into N-4 position to give 3. Cleavage of the third ring of 3 gives 3-benzylacycloguanosine 5, a first 3-aralkilo-9-substituted guanine.