Evaluation of a Fluorescent Lectin-Based Staining Technique for Some Acidophilic Mining Bacteria

A fluorescence-labeled wheat germ agglutinin staining technique (R. K. Sizemore et al., Appl. Environ. Microbiol. 56:2245–2247, 1990) was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. Bacteria identified by others as being gram positive through 16S rRNA sequence analyses, yet clustering near the divergence of that group, stained weakly. Gram-negative bacteria did not stain. Background staining of environmental samples was negligible, and pyrite and soil particles in the samples did not interfere with the staining procedure.     

The in vivo construction of 4-chloro-2-nitrophenol assimilatory bacteria

Pseudomonas sp. N31 was isolated from soil using 3-nitrophenol and succinate as sole source of nitrogen and carbon respectively. The strain expresses a nitrophenol oxygenase and can use either 2-nitrophenol or 4-chloro-2-nitrophenol as a source of nitrogen, eliminating nitrite, and accumulating catechol and 4-chlorocatechol, respectively. The catechols were not degraded further. Strains which are able to utilize 4-chloro-2-nitrophenol as a sole source of carbon and nitrogen were constructed by transfer of the haloaromatic degrading sequences from either Pseudomonas sp. B13 or Alcaligenes eutrophus JMP134 (pJP4) to strain N31. Transconjugant strains constructed using JMP134 as the donor strain grew on 3-chlorobenzoate but not on 2,4-dichlorophenoxyacetate. This was due to the non-induction of 2,4-dichlorophenoxyacetate monooxygenase and 2,4-dichlorophenol hydroxylase. Transfer of the plasmid from the 2,4-dichlorophenoxyacetate negative transconjugant strains to a cured strain of JMP134 resulted in strains which also had the same phenotype. This indicates that a mutation has occurred in pJP4 to prevent the expression of 2,4-dichlorophenoxyacetate monooxygenase and 2,4-dichlorophenol hydroxylase.     

Genetic diversity of Saccharina latissima (Phaeophyceae) along a salinity gradient in the North Sea–Baltic Sea transition zone

The North Sea–Baltic Sea transition zone constitutes a boundary area for the kelp species Saccharina latissima due to a strong salinity gradient operating in the area. Furthermore, the existence of S. latissima there, along Danish waters, is fairly patchy as hard bottom is scarce. In this study, patterns of genetic diversity of S. latissima populations were evaluated along the salinity gradient area of Danish waters (here designated brackish) and were compared to reference sites (here designated marine) outside the gradient area, using microsatellite markers. The results showed that the S. latissima populations were structured into two clusters corresponding to brackish versus marine sites, and that gene flow was reduced both between clusters and between populations within clusters. In addition, results provided empirical evidence that marginal populations of S. latissima in the salinity gradient area exhibited a distinct genetic structure when compared to marine ones. Brackish populations were less diverse, more related, and showed increased differentiation over distance compared to marine populations. The isolation of the brackish S. latissima populations within the salinity gradient area of Danish waters in conjunction with their general low genetic diversity makes these populations vulnerable to ongoing environmental and climate change, predicted to result in declining salinity in the Baltic Sea area that may alter the future distribution and performance of S. latissima in the area.     

Good Computational Practice in the Assignment of Absolute Configurations by TDDFT Calculations of ECD Spectra

Quantum‐mechanical calculations of chiroptical properties have rapidly become the most popular method for assigning absolute configurations (AC) of organic compounds, including natural products. Black‐box time‐dependent Density Functional Theory (TDDFT) calculations of electronic circular dichroism (ECD) spectra are nowadays readily accessible to nonexperts. However, an uncritical attitude may easily deliver a wrong answer. We present to the Chirality Forum a discussion on what can be called good computational practice in running TDDFT ECD calculations, highlighting the most crucial points with several examples from the recent literature. Chirality 28:466–474, 2016. © 2016 Wiley Periodicals, Inc.     

Assessment of type A behavior in preschoolers

Teachers and mothers of 219 four-year-old preschoolers assessed their children for Type A behavior pattern using the Matthews Youth Test for Health (MYTH). The sample was derived from five day care centers with Black, White, and Hispanic teachers and students from middle and lower class families. This study indicates that Type A behavior can be identified in four-year-old preschoolers on the basis of ratings by their teachers. A statistically significant difference was found between the ratings of Type A/B characteristics by teachers and those by mothers; however, these were not related to the sex or ethnicity of the children. Repeated measurements of Type A ratings in a subsample of the children at age five showed no significant change among boys or girls. However, repeated measurements at age six on a second subsample showed that boys had lower mean scores, i.e. were more Type B at age six than at age four.     

Immunocytochemical localization of growth hormone and growth hormone-releasing hormone immunoreactivity in the brain and pituitary of the little brown bat

Anterior pituitary cells exhibiting growth hormone (GH) immunoreactivity and forebrain neurons containing growth hormone-releasing hormone (GHRH) immunoreactivity were identified in little brown bats (Myotis lucifugus) using light microscopic immunocytochemistry. Pituitary somatotropes appeared as ovoid or polyhedral cells that were distributed throughout most of the pars distalis, with the exception of its most rostral region where this cell type was scarce. GH-immunoreactive cells occupied approximately one-third of the total volume of the pars distalis; this proportion did not differ significantly between males and females or in bats collected at different times of year. Neuronal perikarya containing immunoreactive GHRH were observed in the hypothalamic arcuate and suprachiasmatic nuclei, as well as in the cortical and subcortical telencephalon. Fibers were most evident in the median eminence, paraventricular and periventricular nuclei, and molecular layer of the cerebral cortex. Fine fibers were also accumulated in the bed nucleus of the stria terminalis and in the amygdala.     

Comparative modeling of amoebapores and granulysin based on the NK-lysin structure-structural and functional implications.

Amoebapores, the pore-forming polypeptides of the protozoan parasite Entamoeba histolytica, and effector proteins of porcine and human lymphocytes, namely NK-lysin and granulysin, reveal a substantial sequence similarity despite their enormous evolutionary distance. Moreover, all these polypeptides display antibacterial activity and are in higher concentrations cytolytic to eukaryotic cells. The recently solved NMR structure of NK-lysin enabled us to build the three dimensional structures of amoebapores and granulysin by comparative modeling. The generated models revealed the expected similarities, but also fundamental differences with respect to charge distribution, hydrophobicity and core packing. The combination of these structural properties and known biochemical data provides insight in the different membrane-interacting mechanisms of the proteins. For amoebapores, exposed hydrophobic grooves and a locally loosely packed protein core may allow a rearrangement of the protein and therefore may account for its ability to penetrate the target membrane and to form defined ion channels in planar lipid bilayers. In contrast, the structural features of NK-lysin and granulysin appear to be suitable for a membrane-perturbing mode of action rather than for channel formation.     

A Conserved Basic Patch and Central Kink in the Nipah Virus Phosphoprotein Multimerization Domain Are Essential for Polymerase Function

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