The core of the mammalian centriole contains γ-tubulin

Background: The microtubule network, upon which transport occurs in higher cells, is formed by the polymerization of α and β tubulin. The third major tubulin isoform, γ tubulin, is believed to serve a role in organizing this network by nucleating microtubule growth on microtubule-organizing centers, such as the centrosome. Research in vitro has shown that γ tubulin must be restored to stripped centrioles to regenerate the centrosomal functions of duplication and microtubule nucleation.Results We have re-examined the localization of γ tubulin in isolated and in situ mammalian centrosomes using a novel immunocytochemical technique that preserves antigenicity and morphology while allowing increased accessibility. As expected, α tubulin was localized in cytoplasmic and centriolar barrel microtubules and in the associated pericentriolar material. Foci of γ tubulin were observed at the periphery of the organized pericentriolar material, as reported previously, often near the termini of microtubules. A further and major location of γ tubulin was a structure within the proximal end of the centriolar barrel. The distributions were complementary, in that α tubulin was excluded from the core of the centriole, and γ tubulin was excluded from the microtubule barrel.Conclusion We have shown that γ tubulin is localized both in the pericentriolar material and in the core of the mammalian centriole. This result suggests that γ tubulin has a role in the centriolar duplication process, perhaps as a template for growth of the centriolar microtubules, in addition to its established role in the nucleation of astral microtubules.     

A RAPD study of the Sarcostemma group of Cynanchum (Apocynaceae-Asclepiadoideae-Asclepiadeae)

One hundred and thirty-seven accessions of Cynanchum viminale and its relatives, formerly known as Sarcostemma, were studied using randomly amplified polymorphic DNA (RAPD). A fingerprinting technique was used because sequencing had failed to differentiate between morphologically separable groups. Chromosome counts were conducted to establish the ploidy level of the accessions. The banding patterns resulting from RAPD analysis were evaluated with Canonical Analysis of Principal Coordinates, Permanova and neighbour-joining. A strong geographic component was found in the structure of the group. Taxa considered species or subspecies based on morphology often formed coherent groups. The data are interpreted to reflect at least two cycles of diversification: the first one from Madagascar and the second one most likely from the East African–Arabian region, reaching Madagascar again. In mainland Africa, polyploidisation has occurred several times.     

Selective high throughput protein quantification based on UV absorption spectra

The application of high throughput experimentation (HTE) in protein purification process development has created an analytical bottleneck. Recently, a new label‐free and non‐invasive methodology for analyzing multicomponent protein mixtures by means of spectral measurements was presented. Analytics based on the methodology was shown to increase analytical throughput for selective protein quantification significantly, however this was only demonstrated for one particular protein combination. In this work, the possibilities and limitations of the analytical method are investigated further. Principal component analysis (PCA) was performed on a broad range of absorption spectra to investigate their common characteristics and differences. The PCA was used both for cluster analysis and to define a measure for spectral similarity. For binary protein combinations, the calibration precision was shown to decrease exponentially with the defined spectral similarity factor. Knowledge of this correlation can be used to determine a priori whether a calibration will be successful or not. Calibration robustness was investigated by applying the analytics to liquid chromatography performed in HTE mode. Further it was shown, that a spectral difference of 0.6% was sufficient to sucessfully preform a spectral based calibration of two IgG1 monoclonals. Biotechnol. Bioeng. 2013; 110: 448–460. © 2012 Wiley Periodicals, Inc.     

Active protection by bacteriophages T3 and T7 againstE. coli B-and K-specific restriction of their DNA

Summary The bacteriophages T3 and T7 are not modified and restricted byE. coli strains with different host specificity (E. coli B, K, O) in vivo. The phages code for a gene product with the ability toovercomeclassicalrestriction (ocr):ocr ^– mutants are subject to modification and restriction via DNA methylation vs cleavage. The T3 genome possesses recognition sites for the restriction endonuclease R.EcoB which, unless the DNA is B-specifically modified, trigger 5–7 DNA cleavages. Theocr gene function of T3 and T7 is located within the gene 0.3 region of these phages and is not identical with thesam (SAMase) function of T3. The mechanisms ofocr protection remains unclear, while it is certain that this protection by the gene 0.3 protein is exerted in the infected cell and not through over-all modification in the preceding growth cycle of the phage.     

Seed and capsule morphology of Iranian perennial species of Euphorbia (Euphorbiaceae) and its phylogenetic application

Of the 480 species of Euphorbia subgenus Esula, c. 290 occur in the Mediterranean and Irano‐Turanian regions. Turkey and Iran are the most species‐rich countries in Asia with 83 and 74 species, respectively. Following our previous paper on annual species of Iranian Euphorbia, we studied the quantitative and qualitative macro‐ and micromorphological traits of seeds and capsules of 47 perennial species, including E . ferdowsiana sp. nov. , E . sulphurea sp. nov. and E. glareosa, as a first report from Iran. A key for all Iranian perennial Euphorbia spp. based on seed and capsule morphology is provided. The phylogenetic relationships of Iranian species based on internal transcribed spacer (ITS) nuclear and ndhF plastid regions are updated and used for the characterization of the synapomorphies of each clade. Capsule shape, seed shape, seed surface and shape of the caruncle have been found to be homoplastic, whereas the presence or absence of granulate elements on seed surfaces represents a phylogenetically important trait for section delimitation. The capsule surface is synapomorphic for several sections, including Helioscopia (tuberculate‐verrucose), Myrsiniteae (vesiculate) and Esula (granulate), and seed shape is synapomorphic for sections Helioscopia (ellipsoidal), Myrsiniteae (ovoid‐quadrangular) and Herpetorrhizae (pseudo‐hexahedral). Reversals have also taken place in some features, including capsule surface (E. mazandaranica, E. altissima) and seed shape (E. densa, E. aleppica). It seems that ecarunculate seeds are plesiomorphic in sections Helioscopia (E. eriophora) and Herpetorrhizae (E. consanguinea and E. turczaninowii). © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 00 , 000–000.     

Genetic diversity for mycorrhizal symbiosis and phosphate transporters in rice

Phosphorus(P) is a major plant nutrient and developing crops with higher P-use efficiency is an important breeding goal.In this context we have conducted a comparative study of irrigated and rainfed rice varieties to assess genotypic differences in colonization with arbuscular mycorrhizal(AM) fungi and expression of different P transporter genes.Plants were grown in three different soil samples from a rice farm in the Philippines.The data show that AM symbiosis in all varieties was established after 4 weeks of growth under aerobic conditions and that,in soil derived from a rice paddy,natural AM populations recovered within6 weeks.The analysis of AM marker genes(AM1,AM3,AM14) and P transporter genes for the direct Pi uptake(PT2,PT6) and AM-mediated pathway(PT11,PT13) were largely in agreement with the observed root AM colonization providing a useful tool for diversity studies.Interestingly,delayed AM colonization was observed in the aus-type rice varieties which might be due to their different root structure and might confer an advantage for weed competition in the field.The data further showed that P-starvation induced root growth and expression of the high-affinity P transporter PT6 was highest in the irrigated variety IR66 which also maintained grain yield under P-deficient field conditions.     

Switching between penta- and hexacoordination with salen-silicon-complexes

The reaction between phenyltrichlorosilane and the tetradentate ligands o-HO-C₆H₄-C(CH₃)N-(CH₂)_n-NC(CH₃)-o-C₆H₄-OH (n = 2, 3, 4), supported by an amine base, yields pentacoordinate silicon complexes (C₆H₅)Si-[o-O-C₆H₄-C(CH₃)N-(CH₂)_n-N-C(CH₂)-o-C₆H₄-O] with enamine functionalized ligands. This reaction pattern can be transferred onto various ligands of 2-iminomethylphenolate-type. The resulting pentacoordinate silicon complexes react with a variety of Brønsted acids HY to yield hexacoordinate salen silicon complexes (C₆H₅)(Y)Si-[o-O-C₆H₄-C(CH₃)N-(CH₂)_n-NC(CH₃)-o-C₆H₄-O] (Y = benzoate, picrate, 8-oxyquinolinate, 2-oxy-1,4-naphthoquinonate, p-tert-butylphenolate, (5-phenyltetrazol)-2-ide, fluoride, tetrafluoroborate). Hexacoordination of their Si-atoms was confirmed by ²⁹Si NMR spectroscopy and, in some cases, by X-ray crystal structure analysis. Examples for similarities and differences in the coordination behavior of the silicon atom and its heavier congeners (Ge, Sn) in the salen-type coordination sphere as well as data regarding the nucleophilicity of some of these novel enamine complexes are presented.     

Isolation and characterization of a new spore-forming sulfate-reducing bacterium growing by complete oxidation of catechol

A new mesophilic sulfate-reducing bacterium, strain Groll, was isolated from a benzoate enrichment culture inoculated with black mud from a freshwater ditch. The isolate was a spore-forming, rod-shaped, motile, gram-positive bacterium. This isolate was able of complete oxidation of several aromatic compounds including phenol, catechol, benzoate, p-and m-cresol, benzyl alcohol and vanillate. With hydrogen and carbon dioxide, formate or O-methylated aromatic compounds, autotrophic growth during sulfate reduction or homoacetogenesis was demonstrated. Lactate was not used as a substrate. SO _inf4 ^sup2- , SO _inf3 ^sup2- , and S₂O _inf3 ^sup2- were utilized as electron acceptors. Although strain Groll originated from a freshwater habitat, salt concentrations of up to 30 g·l^-1 were tolerated. The optimum temperature for growth was 35–37°C. The G+C content of DNA was 42.1 mol%. This isolate is described as a new species of the genus Desulfotomaculum.     

MLVA as a Tool for Public Health Surveillance of Human Salmonella Typhimurium: Prospective Study in Belgium and Evaluation of MLVA Loci Stability

Surveillance of Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) is generally considered to benefit from molecular techniques like multiple-locus variable-number of tandem repeats analysis (MLVA), which allow earlier detection and confinement of outbreaks. Here, a surveillance study, including phage typing, antimicrobial susceptibility testing and the in Europe most commonly used 5-loci MLVA on 1,420 S. Typhimurium isolates collected between 2010 and 2012 in Belgium, was used to evaluate the added value of MLVA for public health surveillance. Phage types DT193, DT195, DT120, DT104, DT12 and U302 dominate the Belgian S. Typhimurium population. A combined resistance to ampicillin, streptomycin, sulphonamides and tetracycline (ASSuT) with or without additional resistances was observed for 42.5% of the isolates. 414 different MLVA profiles were detected, of which 14 frequent profiles included 44.4% of the S. Typhimurium population. During a serial passage experiment on selected isolates to investigate the in vitro stability of the 5 MLVA loci, variations over time were observed for loci STTR6, STTR10, STTR5 and STTR9. This study demonstrates that MLVA improves public health surveillance of S. Typhimurium. However, the 5-loci MLVA should be complemented with other subtyping methods for investigation of possible outbreaks with frequent MLVA profiles. Also, variability in these MLVA loci should be taken into account when investigating extended outbreaks and studying dynamics over longer periods.