Overview of microbial biofilms

As the success of this two-issue special section of the Journal of Industrial Microbiology attests, the study of microbial biofilms is truly burgeoning as the uniqueness and the importance of this mode of growth is increasingly recognized. Because of its universality the biofilm concept impacts virtually all of the subdivisions of Microbiology (including Medical, Dental, Agricultural, Industrial and Environmental) and these two issues incorporate contributions from authors in all of these disciplines. Some time ago we reasoned that bacteria cannot possibly be aware (sic) of their precise location, in terms of this spectrum of anthrocentric subspecialties, and that their behavior must be dictated by a standard set of phenotypic responses to environmental conditions in what must seem to them (sic) to be a continuum of very similar aquatic ecosystems. In this overview I will, therefore, stress the common features of microbial biofilms that we should bear in mind as we use this simple universal concept to seek to understand bacterial behavior in literally hundreds of aquatic ecosystems traditionally studied by dozens of subspecies of microbiologists reared in sharply different scientific and academic conventions.     

Systematic revision of Aluntiini Emeljanov, 1979 (Hemiptera: Fulgoromorpha: Dictyopharidae: Dictyopharinae): reclassification,phylogenetic analysis,and biogeography

The dictyopharid planthopper tribe Aluntiini s.l. is revised and reclassified into two tribes: Aluntiini s.s. and Arjunini Song & Szwedo trib. nov. The tribe Aluntiini s.s. includes five genera: Aluntia Stål, 1866; D endrophora Melichar, 1903 stat. rev. ; Dictyomorpha Melichar, 1912; Indodictyophara Liang & Song, 2012; and Madagascaritia Song & Liang gen. nov. The new tribe Arjunini comprises two genera – Arjuna Muir, 1934 and Pippax Emeljanov, 2008 – both moved from Aluntiini s.l. Four new species – A luntia longicephalica Song & Szwedo sp. nov. , Madagascaritia angusta Song & Liang sp. nov. , Arjuna maai Song & Wang sp. nov. , and Arjuna muiri Song & Wang sp. nov. – are described. A morphologically based phylogenetic analysis is undertaken for Aluntiini, Arjunini, and the representatives of Dictyopharini, Hastini, Orthopagini, and the fossil Worskaitini within Dictyopharinae, all distributed in the Old World. A matrix of 129 characters of the habitus, coloration, head, thorax, and male and female genitalia of the adults was used for the cladistic analysis. The phylogenetic results show that Aluntiini s.l. as placed in Dictyopharidae is well supported, but it is distinctly paraphyletic and should be separated into two unambiguous tribes. A palaeotropical distribution pattern displayed by Aluntiini is suggested. The origin and diversification of Aluntiini are discussed preliminarily. © 2015 The Linnean Society of London     

Genome-wide identification of specific oligonucleotides using artificial neural network and computational genomic analysis

Background  

Genome-wide identification of specific oligonucleotides (oligos) is a computationally-intensive task and is a requirement for designing microarray probes, primers, and siRNAs. An artificial neural network (ANN) is a machine learning technique that can effectively process complex and high noise data. Here, ANNs are applied to process the unique subsequence distribution for prediction of specific oligos.     

Basolateral K channels in an insect epithelium. Channel density, conductance, and block by barium

K channels in the basolateral membrane of insect hindgut were studied using current fluctuation analysis and microelectrodes. Locust recta were mounted in Ussing-type chambers containing Cl-free saline and cyclic AMP (cAMP). A transepithelial K current was induced by raising serosal [K] under short-circuit conditions. Adding Ba to the mucosal (luminal) side under these conditions had no effect; however, serosal Ba reversibly inhibited the short-circuit current (Isc), increased transepithelial resistance (Rt), and added a Lorentzian component to power density spectra of the Isc. A nonlinear relationship between corner frequency and serosal [Ba] was observed, which suggests that the rate constant for Ba association with basolateral channels increased as [Ba] was elevated. Microelectrode experiments revealed that the basolateral membrane hyperpolarized when Ba was added: this change in membrane potential could explain the nonlinearity of the 2 pi fc vs. [Ba] relationship if external Ba sensed about three-quarters of the basolateral membrane field. Conventional microelectrodes were used to determine the correspondence between transepithelially measured current noise and basolateral membrane conductance fluctuations, and ion-sensitive microelectrodes were used to measure intracellular K activity (acK). From the relationship between the net electrochemical potential for K across the basolateral membrane and the single channel current calculated from noise analysis, we estimate that the conductance of basolateral K channels is approximately 60 pS, and that there are approximately 180 million channels per square centimeter of tissue area.     

Restriction-map variation with the yellow-achaete-scute region in five populations of Drosophila melanogaster

It has been proposed that the degree of recombination for a genomic region will affect the level of both nucleotide heterozygosity and the density of transposable elements. Both features of genomic diversity have been examined in a number of recent reports for regions undergoing relatively normal levels of recombination in Drosophila melanogaster. In this study the genomic variation associated with yellow-achaete- scute loci located at the tip of the X chromosome is examined by six- cutter restriction mapping. In this region, as usual for regions adjacent to telomeres, crossing-over is dramatically reduced, and published studies of visible mutants indicate extremely little restriction-map variation. Eight six-cutter restriction endonucleases were used to locate sequence variation in 14- and 16.5-kb regions in 109 lines sampled from North America, Africa, and Europe. The overall level of heterozygosity is estimated as 0.29%. Nine large insertions, all presumed to be transposable elements, were observed. Base-pair heterozygosity appears to be reduced compared with regions having normal levels of recombination. The estimated heterozygosity is much higher than reported in earlier studies of restriction-map variation among visible mutations in the complex. The incidence of large insertions is not elevated compared with that in other regions of the genome. This suggests that asymmetric synapsis and exchange is not an important mechanism for the elimination of transposable elements.      

Characterisation of<Emphasis Type="Italic">fusarium graminearum</Emphasis> and<Emphasis Type="Italic">F. culmorum</Emphasis> isolates by mycotoxin production and aggressiveness to wheat

A total of 27Fusarium culmorum isolates from Germany and 41F. graminearum isolates from Kenya were investigated for aggressiveness and mycotoxin production on wheat ears. In addition, ergosterol content of the kernels from ears inoculated withF. graminearum was determined and theF. culmorum isolates were tested for mycotoxin productionin vitro. For both pathogens, isolates markedly differed in aggressiveness. 59% and 37% of theF. culmorum isolates produced NIV and DON, respectively,in vivo andin vitro. The DON-producing isolates also produced 3-acDONin vitro. The more aggressive isolates produced mainly DON while the less aggressive isolates produced mainly NIV. 12% and 85% of theF. graminearum isolates produced NIV and DON, respectively. The highly aggressive isolates produced higher amounts of DON, aggressiveness being highly correlated to DON content in the kernels. NIV-producing isolates were less aggressive. Ergosterol content of kernels was moderately correlated to aggressiveness but highly correlated to DON content. Disease severity was associated with kernel weight reduction.     

Examination of the Baltic amber inclusion surface using SEM techniques and X-ray microanalysis

Amber inclusion of the leafhopper, partly revealed from the resin and covered with inorganic, blackish and shining layer was examined using light and scanning electron microscopes. It is placed in the genus Protodikraneura of the recently described tribe Protodikraneurini (Insecta: Hemiptera: Cicadellidae: Typhlocybinae). SEM examination was conducted using microscope Hitachi S-3400N, equipped with X-ray EDS spectrometer of Thermo Noran Company, suitable for local chemical analyses. Part of the tegmen of the inclusion with details of its morphology is visible both in light and SEM microscopy. Its detailed structure and composition remained unidentified under light microscopy. Surface morphology and the chemical composition of the layer covering inclusion in particular, were studied in details using SEM microscope with the EDS X-ray spectrometer. The layer covering revealed portion of the inclusion presented various surface structures and various topographic features. The structure (grains of different shapes and sizes) is diversified in respect to their chemical composition. Qualitative and quantitative EDS analyses as well as the structure of grains building fragment of the layer were conducted. The surface of inclusion is partly covered with pyrite FeS₂, probably with one of the variations of the pyrite — the marcasite. Other portions of the surface layer differ in chemical composition and in physical structure of the grains, containing high amount of aluminum and silicon.