Biosynthesis of the antifungal haterumalide, oocydin A, in Serratia, and its regulation by quorum sensing, RpoS and Hfq.

Polyketides represent an important class of bioactive natural products with a broad range of biological activities. We identified recently a large trans-acyltransferase (AT) polyketide synthase gene cluster responsible for the biosynthesis of the antifungal, anti-oomycete and antitumor haterumalide, oocydin A (ooc). Using genome sequencing and comparative genomics, we show that the ooc gene cluster is widespread within biocontrol and phytopathogenic strains of the enterobacteria, Serratia and Dickeya. The analysis of in frame deletion mutants confirmed the role of a hydroxymethylglutaryl-coenzyme A synthase cassette, three flavin-dependent tailoring enzymes, a free-standing acyl carrier protein and two hypothetical proteins in oocydin A biosynthesis. The requirement of the three trans-acting AT domains for the biosynthesis of the macrolide was also demonstrated. Expression of the ooc gene cluster was shown to be positively regulated by an N-acyl-L-homoserine lactone-based quorum sensing system, but operating in a strain-dependent manner. At a post-transcriptional level, the RNA chaperone, Hfq, plays a key role in oocydin A biosynthesis. The Hfq-dependent regulation is partially mediated by the stationary phase sigma factor, RpoS, which was also shown to positively regulate the synthesis of the macrolide. Our results reveal differential regulation of the divergently transcribed ooc transcriptional units, highlighting the complexity of oocydin A production.This research was supported by the EU Marie-Curie Intra-European Fellowship for Career Development (FP7-PEOPLE-2011-IEF) Grant No. 298003. The Salmond laboratory is supported by funding through the Biotechnology and Biological Sciences Research Council, BBSRC (UK). Work with plant pathogens was carried out under DEFRA Licence No. 50864/197900/1.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/1462-2920.1283

Obtaining and Structural Characterization of M-type Hexaferrites Doped with Two Cations in the Fe3+ Sites

A study of the microstructural and structural properties of M-type barium hexaferrites (BaM) samples doped with two dopants in the Fe3+ sites: (Co3+, Al3+), (Co2+, Ti4+) and (Co2+, Sn4+) is reported. The samples were obtained using the conventional ceramic method. The structure was investigated by using of X-ray diffraction (XRD) to determine the dopant distribution in the Fe3+ sites

A note on the SG(m) test

López et al. (Reg Sci Urban Econ 40(2–3):106–115, 2010) introduce a nonparametric test of spatial dependence, called SG(m). The test is claimed to be consistent and asymptotically Chi-square distributed. Elsinger (Reg Sci Urban Econ 43(5):838–840, 2013) raises doubts about the two properties. Using a particular counterexample, he shows that the asymptotic distribution of the SG(m) test may be far from the Chi-square family; the property of consistency is also questioned. In this note, the authors want to clarify the properties of the SG(m) test. We argue that the cause of the conflict is in the specification of the symbolization map. The discrepancies can be solved by adjusting some of the definitions made in the original paper. Moreover, we introduce a permutational bootstrapped version of the SG(m) test, which is powerful and robust to the underlying statistical assumptions. This bootstrapped version may be very useful in an applied context

N-carboximetil-treonina: síntesis propiedades ácidas y caracterización en estado sólido

Se propone la síntesis de N-Carboximetil-D,L-Treonina (H2CMT=H2L) por condensación de D,L-treoninato y cloroacetato potásicos, desalinización parcial en medio neutro y posterior cambio iónico por resina catiónica en forma ácida. Rendimiento: 75%. El tratamiento mediante el programa HYPERQUAD de 238 datos potenciométricos de tres valoraciones de H2CMT frente a KOH en KNO, O.IM a 25.00±0.05 ºC y atmósfera inerte (N2) permite la determinación de las constantes de formación de sus especies protonadas, con las que se simula la curva de valoración. En estado sólido, el aminodiácido se caracteriza por su espectro IR y por análisis ténnico (TG-A TD)

Genomic analysis reveals the major driving forces of bacterial life in the rhizosphere

A global analysis of Pseudomonas putida gene expression performed during the interaction with maize roots revealed how a bacterial population adjusts its genetic program to the specific conditions of this lifestyle

Mice lacking ataxin-1 display learning deficits and decreased hippocampal paired-pulse facilitation.

Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disorder characterized by ataxia, progressive motor deterioration, and loss of cerebellar Purkinje cells. To investigate SCA1 pathogenesis and to gain insight into the function of the SCA1 gene product ataxin-1, a novel protein without homology to previously described proteins, we generated mice with a targeted deletion in the murine Sca1 gene. Mice lacking ataxin-1 are viable, fertile, and do not show any evidence of ataxia or neurodegeneration. However, Sca1 null mice demonstrate decreased exploratory behavior, pronounced deficits in the spatial version of the Morris water maze test, and impaired performance on the rotating rod apparatus. Furthermore, neurophysiological studies performed in area CA1 of the hippocampus reveal decreased paired-pulse facilitation in Sca1 null mice, whereas long-term and post-tetanic potentiations are normal. These findings demonstrate that SCA1 is not caused by loss of function of ataxin-1 and point to the possible role of ataxin-1 in learning and memory

Viunalikeviruses are environmentally common agents of horizontal gene transfer in pathogens and biocontrol bacteria.

Bacteriophages have been used as natural biocontrol and therapeutic agents, but also as biotechnological tools for bacterial engineering. We showed recently that the transducing bacteriophage ϕMAM1 is a ViI-like phage and a member of the new genus, 'Viunalikevirus'. Here, we show that four additional ViI-like phages and three new environmentally isolated viunalikeviruses, all infecting plant and human pathogens, are very efficient generalised transducers capable of transducing chromosomal markers at frequencies of up to 10(-4) transductants per plaque-forming unit. We also demonstrate the interstrain transduction of plasmids and chromosomal markers, including genes involved in anabolism, genes for virulence and genes encoding secondary metabolites involved in biocontrol. We propose that all viunalikeviruses are likely to perform efficient horizontal gene transfer. Viunalikeviruses therefore represent useful agents for functional genomics and bacterial engineering, and for chemical and synthetic biology studies, but could be viewed as inappropriate choices for phage therapy.This research was supported by the EU Marie-Curie Intra-European Fellowship for Career Development (FP7- PEOPLE-2011-IEF) grant number 298003.This is the version of record of the article "Viunalikeviruses are environmentally common agents of horizontal gene transfer in pathogens and biocontrol bacteria" published in ISME Journal on August 2104 under the NPG Open Access option. The published version of record is available on the journal website at http://dx.doi.org/10.1038/ismej.2014.15

N-carboxyrnethyl-D, L-threonine. Synthesis, acid properties and characterization in solid state

Se propone la síntesis de N-Carboximetil-D,L-Treonina (H2 CMT=H1 L) por condensación de D,L-treoninato y cloroacetato potásicos, desalinización parcial en medio neutro y posterior cambio iónico por resina catiónica en forma ácida. Rendimiento: 75%. El tratamiento mediante el programa HYPERQUAD de 238 datos potenciométricos de tres valoraciones de H2 CMT frente a KOH en KNO, O.IM a 25.00±0.05 oC y atmósfera inerte (N2 ) permite la determinación de las constantes de formación de sus especies protonadas, con las que se simula la curva de valoración. En estado sólido, el aminodiácido se caracteriza por su espectro IR y por análisis ténnico (TG-A TD).N-Carboxymethyl-D,L-threonine (H2 CMT=H2 L) was obtained by reaction of D,L threonine and chloroacetate in alkaline medium and followed by cation change with Amberlite IR-120(H) of the desalinized mother liquor. Yield: 75%. The treatment of 238 potentiometric data from three mixed solutions (H2 L +HCI) by HYPERQUAD program gives to log ,,=8.73(01), log 1 2 =1 1.22(01) and log 1.1=12.76(02) for the species HL-, H2 L and H. 1L' at 298°K, I=O.IM (KNO.1) and N2 inert atmosfere. These constants give a good simulation of the H2 L titration curve. The infrared spectra and TG-DT A data of H2 CMT are al so discussed on the basis of its zwitterionic structure

High-affinity chemotaxis to histamine of the human pathogen Pseudomonas aeruginosa

FEMS 2019: 8th congress of European Microbiologists, in Glasgow, Scotland, 7-11 July 201