The production of N-acyl homoserine lactones (AHLs) is widely distributed within the marine Roseobacter clade, and it was proposed that AHL-mediated quorum sensing (QS) is one of the most common ...cell-to-cell communication mechanisms in roseobacters. The traits regulated by AHL-mediated QS are yet not known for members of the Roseobacter clade, but production of the antibiotic tropodithietic acid (TDA) was supposed to be controlled by AHL-mediated QS in Phaeobacter spp. We describe here for the first time the functional role of luxR and luxI homologous genes of an organism of the Roseobacter clade, i.e., pgaR and pgaI in Phaeobacter gallaeciensis. Our results demonstrate that the AHL synthase gene pgaI is responsible for production of N-3-hydroxydecanoylhomoserine lactone (3OHC10-HSL). Insertion mutants of pgaI and pgaR are both deficient in TDA biosynthesis and the formation of a yellow-brown pigment when grown in liquid marine broth medium. This indicates that in P. gallaeciensis the production of both secondary metabolites is controlled by AHL-mediated QS. Quantitative real-time PCR showed that the transcription level of tdaA, which encodes an essential transcriptional regulator for TDA biosynthesis, decreased 28- and 51-fold in pgaI and pgaR genetic backgrounds, respectively. These results suggest that both the response regulator PgaR and the 3OHC10-HSL produced by PgaI induce expression of tdaA, which in turn positively regulates expression of the tda genes. Moreover, we confirmed that TDA can also act as autoinducer in P. gallaeciensis, as previously described for Silicibacter sp. strain TM1040, but only in the presence of the response regulator PgaR.
Emerging evidence implicates white matter (WM) abnormalities in the pathophysiology of schizophrenia. However, there is considerable heterogeneity in the presentation of WM abnormalities in the ...existing studies. The object of this study was to evaluate WM integrity in a large sample of patients with first-episode (FE) and chronic schizophrenia in comparison to matched control groups. Our goal was to assess whether WM findings occurred early in the illness or whether these abnormalities developed with the illness over time.
Participants included 114 patients with schizophrenia (31 FE and 83 chronic patients) and 138 matched controls. High-resolution structural and diffusion tensor images were obtained on all participants. Measures of fractional anisotropy (FA) were calculated for the 4 cortical lobes and the cerebellum and brain stem.
FA was significant lower in patients vs controls in the whole brain and individually in the frontal, parietal, occipital, and temporal lobes. FA was not significantly different in the brain stem or cerebellum. FA differences were significant only in patients with chronic schizophrenia and not in the FE group.
We found global differences in the WM microstructure in patients with chronic but not FE schizophrenia. These findings suggest progressive alterations in WM microstructure.
Ageing surveillance programmes for Swiss nuclear power plants were started about ten years ago. The following contribution gives an overview of these programmes. They deal with ageing phenomena of ...materials of mechanical and electrical components, as well as civil structures. For each safety relevant component, the known ageing mechanisms are identified, and the maintenance, testing, inspection and monitoring programmes are then examined with respect to their suitability for detecting the ageing degradation. Programmes and procedures may be adjusted, or new ones introduced to ensure state of science and technology ageing surveillance. Documentation of the plant-specific ageing surveillance programmes is prepared by the nuclear power plant operators and given to the Swiss Federal Nuclear Safety Inspectorate for assessment. Experience with the ageing surveillance programmes over the last ten years shows favourable results for the monitoring of ageing and safe operation of the plants.
We present a complete set of elastic and structural parameters for wurtzite and zinc-blende group-III nitrides, GaN, InN and AIN, calculated ab initio. A high degree of accuracy is ensured using the ...Heyd-Scuseria-Ernzerhof (HSE) hybrid functional approach. Both lattice and elastic constants are obtained by means of the stresses acting on the crystal, rather than by a minimization of the lattice energy. Our results show very good agreement with available experimental data. Furthermore, all the independent internal strain parameters of the wurtzite nitrides are reported.
Traditionally, changes in the microbial population of the nose have been assessed using conventional culture techniques. Sequencing of bacterial 16S rRNA genes demonstrated that the human nose is ...inhabited by a rich and diverse bacterial microbiome that cannot be detected using culture-based methods. The goal of this study was to describe the nasal microbiome of healthy cats, cats with nasal neoplasia, and cats with feline upper respiratory tract disease (FURTD).
DNA was extracted from nasal swabs of healthy cats (n = 28), cats with nasal neoplasia (n = 16), and cats with FURTD (n = 15), and 16S rRNA genes were sequenced. High species richness was observed in all samples. Rarefaction analysis revealed that healthy cats living indoors had greater species richness (observed species p = 0.042) and Shannon diversity (p = 0.003) compared with healthy cats living outdoors. Higher species richness (observed species p = 0.001) and Shannon diversity (p<0.001) were found in middle-aged cats in comparison to healthy cats in different age groups. Principal coordinate analysis revealed separate clustering based on similarities in bacterial molecular phylogenetic trees of 16S rRNA genes for indoor and outdoor cats. In all groups examined, the most abundant phyla identified were Proteobacteria, Firmicutes, and Bacteroidetes. At the genus level, 375 operational taxonomic units (OTUs) were identified. In healthy cats and cats with FURTD, Moraxella spp. was the most common genus, while it was unclassified Bradyrhizobiaceae in cats with nasal neoplasia. High individual variability was observed.
This study demonstrates that the nose of cats is inhabited by much more variable and diverse microbial communities than previously shown. Future research in this field might help to develop new diagnostic tools to easily identify nasal microbial changes, relate them to certain disease processes, and help clinicians in the decision process of antibiotic selection for individual patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
(trip
Sn)
(trip = 2,4,6-i-Pr
C
H
) reacts with Mg(i) reductants (LMg)
(L = HCC(Me)N(dipp)
) and (L'Mg)
(L' = HCC(Me)N(mes)
) with Sn-C bond cleavage and formation of the novel metalloid tin cluster ...Sn
trip
1 or elemental tin. 1, which contains Sn atoms in the formal oxidation states 0, +I and +II, and the side products LMgtrip (2) and L'Mgtrip (3) were characterized spectroscopically and by single crystal X-ray diffraction.
In recent years, the goal of treatment for individuals with schizophrenia has shifted from symptom control to functional recovery. For recovery to occur, the substantial cognitive impairments ...associated with this disorder must be addressed. Advances in neuroscience have paved the way for the development of more effective behavioral and pharmacologic treatments. Behavioral interventions such as cognitive training are tapping into the innate plasticity and adaptive qualities of the brain. Emerging pharmacologic treatments are targeting new neurotransmitters and systems, such as the glutamatergic system and the nicotinic-cholinergic system, which are involved in the cognitive and sensory deficits that lead to impairment. The best chances for recovery will most likely occur by combining behavioral and pharmacologic interventions.
PDF
