Staphylococcal phenotypes induced by naturally occurring and synthetic membrane-interactive polyphenolic ß-lactam resistance modifiers.

Galloyl catechins, in particular (-)-epicatechin gallate (ECg), have the capacity to abrogate ß-lactam resistance in methicillin-resistant strains of Staphylococcus aureus (MRSA); they also prevent biofilm formation, reduce the secretion of a large proportion of the exoproteome and induce profound changes to cell morphology. Current evidence suggests that these reversible phenotypic traits result from their intercalation into the bacterial cytoplasmic membrane. We have endeavoured to potentiate the capacity of ECg to modify the MRSA phenotype by stepwise removal of hydroxyl groups from the B-ring pharmacophore and the A:C fused ring system of the naturally occurring molecule. ECg binds rapidly to the membrane, inducing up-regulation of genes responsible for protection against cell wall stress and maintenance of membrane integrity and function. Studies with artificial membranes modelled on the lipid composition of the staphylococcal bilayer indicated that ECg adopts a position deep within the lipid palisade, eliciting major alterations in the thermotropic behaviour of the bilayer. The non-galloylated homolog (-)-epicatechin enhanced ECg-mediated effects by facilitating entry of ECg molecules into the membrane. ECg analogs with unnatural B-ring hydroxylation patterns induced higher levels of gene expression and more profound changes to MRSA membrane fluidity than ECg but adopted a more superficial location within the bilayer. ECg possessed a high affinity for the positively charged staphylococcal membrane and induced changes to the biophysical properties of the bilayer that are likely to account for its capacity to disperse the cell wall biosynthetic machinery responsible for ß-lactam resistance. The ability to enhance these properties by chemical modification of ECg raises the possibility that more potent analogs could be developed for clinical evaluation.

Vertebral artery halo sign in patients with stroke: a key clue for the prompt diagnosis of giant cell arteritis.

BACKGROUND AND PURPOSE: The purpose of this study was to describe typical ultrasonographic findings of vertebral arteries in patients affected by giant cell arteritis. METHODS: Color duplex sonography was used to asses the cervical arteries within 24 hours from stroke onset in 1237 patients. Vertebral arteritis was considered if concentric, homogeneous, and smooth hypoechogenic mural thickening (the so-called halo sign) was present in at least 1 cervical segment of the vertebral artery. If the patient showed such findings, an ultrasound examination of the temporal artery was also performed. Patients with probable giant cell arteritis were treated with high-dose intravenous methylprednisolone in association with antiplatelet therapy. Temporal artery biopsy was carried out by a vascular surgeon in the site targeted by the ultrasonographer. RESULTS: Five patients were diagnosed as having vertebral arteritis according to ultrasound criteria. All of them had initial neurological deficit due to infarctions affecting the vertebrobasilar territory. One patient died due to aspiration pneumonia, whereas the others were independent at discharge. All patients had a positive biopsy for giant cell arteritis. CONCLUSIONS: Vertebral artery involvement in giant cell arteritis may be suspected by color duplex sonography. This fact would allow a prompt diagnosis and treatment of this otherwise fatal disease. Because duplex ultrasonography is a usual test performed on patients with stroke, the recognition of the halo sign in vertebral arteries may be of crucial interest in selected cases.

Characterization of some bacterial strains isolated from animal clinical materials and identified as Corynebacterium xerosis by molecular biological techniques.

Eighteen Corynebacterium xerosis strains isolated from different animal clinical specimens were subjected to phenotypic and molecular genetic studies. On the basis of the results of the biochemical characterization, the strains were tentatively identified as C. xerosis. Phylogenetic analysis based on comparative analysis of the sequences of 16S rRNA and rpoB genes revealed that the 18 strains were highly related to C. xerosis, C. amycolatum, C. freneyi, and C. hansenii. There was a good concordance between 16S rRNA and partial rpoB gene sequencing results, although partial rpoB gene sequencing allowed better differentiation of C. xerosis. Alternatively, C. xerosis was also differentiated from C. freneyi and C. amycolatum by restriction fragment length polymorphism analysis of the 16S-23S rRNA gene intergenic spacer region. Phenotypic characterization indicated that besides acid production from D-turanose and 5-ketogluconate, 90% of the strains were able to reduce nitrate. The absence of the fatty acids C(14:0), C(15:0), C(16:1)omega 7c, and C(17:1)omega 8c can also facilitate the differentiation of C. xerosis from closely related species. The results of the present investigation demonstrated that for reliable identification of C. xerosis strains from clinical samples, a combination of phenotypic and molecular-biology-based identification techniques is necessary.

Staging of alpha-synuclein in the olfactory bulb in a model of Parkinson's disease: cell types involved.

Impaired olfaction is an early symptom of Parkinson's disease. The underlying neuropathology likely includes alpha-synucleinopathy in the olfactory bulb at an earlier stage (Braak's stage1) than pathology in the substantia nigra, which is not observed until stage 3. In this report, we investigated the distribution and cell types affected by alpha-synuclein in the olfactory bulb of transgenic mice (2-8 months of age) expressing the human A53T variant of alpha-synuclein. alpha-Synuclein immunostaining progressively affects interneurons and mitral cells. Double labeling studies demonstrate that dopaminergic cells are hardly involved, whereas glutamatergic- and calcium binding protein-positive cells are severely affected. This temporal evolution and the cell types expressing alpha-synuclein are reminiscent of idiopathic Parkinson's disease and support the usefulness of this model to address specific topics in the premotor phase of the disease.

alpha-Synucleinopathy in the human olfactory system in Parkinson's disease: involvement of calcium-binding protein- and substance P-positive cells.

Hyposmia is an early symptom of idiopathic Parkinson's disease but the pathological bases of such dysfunction are largely unknown. The distribution of alpha-synuclein, which forms Lewy bodies and Lewy neurites, and the types of neurons (based on their neurotransmitters) affected by alpha-synucleinopathy were investigated in the olfactory system in Parkinson's disease. Immunohistochemical distribution of alpha-synuclein and its co-localization with tyrosine hydroxylase, somatostatin, calbindin, calretinin, parvalbumin and substance P in the olfactory bulb, anterior olfactory nucleus, olfactory tubercle and piriform, periamygdaloid and rostral entorhinal cortices of idiopathic Parkinson's disease cases (n = 11) and age-matched controls (n = 11) were investigated. Lewy bodies and Lewy neurites were present in the olfactory bulb, particularly in mitral cells and in the inner plexiform layer. alpha-synuclein was particularly abundant in the different divisions of the anterior olfactory nucleus (bulbar, intrapeduncular, retrobulbar and cortical). In contrast, Lewy bodies and Lewy neurites were less abundant in the olfactory tubercle and olfactory cortices. In the olfactory bulb, anterior olfactory nucleus and olfactory cortices, cells affected by alpha-synucleinopathy rarely co-localized tyrosine hydroxylase or somatostatin, but they frequently co-localized calbindin, calretinin, parvalbumin and substance P. The present data provide evidence that alpha-synucleinopathy affects neurons along the olfactory pathway. Dopamine- and somatostatin-positive cells are rarely affected; whereas the cell types most vulnerable to neurodegeneration include glutamate- (mitral cells), calcium-binding protein- and substance P-positive cells. These results provide data on the distribution and cell types involved by alpha-synucleinopathy in the human olfactory system during Parkinson disease that may be useful for future clinical investigation.

Trastornos no motores de la enfermedad de Parkinson: introducción y generalidades / Non-motor disorders in Parkinson’s disease: introduction and general features

Introducción. Hace ya casi 200 años, James Parkinson describió con detalle la enfermedad que hoy lleva su nombre, centrándose no sólo en los trastornos motores sino también en los síntomas no motores que sufren estos pacientes. Desarrollo. Los síntomas no motores en enfermos parkinsonianos son prevalentes e interfieren en su calidad de vida. En los últimos años se ha intentado resolver el problema de su infradiagnóstico mediante cuestionarios y escalas. Asimismo, algunos de estos síntomas se postulan como predictores de la enfermedad y se plantea que individuos asintomáticos desde el punto de vista motor que sufran alguno de estos síntomas no motores podrían ser dianas de estrategias neuroprotectoras cuando se disponga de ellas. Conclusiones. Los síntomas no motores son frecuentes y tienen gran impacto en la calidad de vida de los enfermos parkinsonianos, por lo que es necesario reconocerlos y tratarlos. Su papel como predictores de la enfermedad a día de hoy aún no está aclarado (AU)

Introduction. Two hundred years ago James Parkinson accurately described the disease that bears his name today, focusing not only on motor aspects but also on non-motor symptoms suffered by these patients. Development. Non-motor symptoms are prevalent and decrease the quality of life of the patients with Parkinson’s disease. In recent years, some non-motor scales have been developed to avoid the problem of underdiagnosis. Moreover, some of them have been proposed as clinical predictors for Parkinson’s disease and it is has been suggested that individuals with any of these non-motor symptoms and without motor manifestations of the disease could be the aim for neuroprotective therapies when they become available. Conclusions. Non-motor symptoms are prevalent and have a great impact in the quality of life of patients. Therefore, it is important to detect and treat them. Their role as predictors of the disease is unclear yet (AU)

Enzymatic permeabilization of the thecate dinoflagellate Alexandrium minutum (Dinophyceae) yields detection of intracellularly associated bacteria via catalyzed reporter deposition-fluorescence in situ hybridization.

The enzymatic permeabilization procedure described here allows the detection of intracellular bacteria in the thecate dinoflagellate Alexandrium minutum by using catalyzed reporter deposition-fluorescence in situ hybridization. The combined use of propidium iodide and calcofluor for confocal laser scanning microscopy, together with general and specific fluorescent bacterial probes, demonstrated the intracellular presence of bacteria, including members of the phylum Bacteroidetes.

Hoeflea alexandrii sp. nov., isolated from the toxic dinoflagellate Alexandrium minutum AL1V.

A Gram-negative, aerobic, non-symbiotic bacterium (AM1V30(T)) was isolated from the toxic dinoflagellate Alexandrium minutum AL1V. On the basis of 16S rRNA gene sequence similarity, strain AM1V30(T) was most closely related (97.4 % similarity) to the type strain of Hoeflea marina, which belongs to the family Phyllobacteriaceae within the order Rhizobiales of the class Alphaproteobacteria. A polyphasic approach was used to clarify the taxonomic position of strain AM1V30(T). During the course of this study, a second species was described by others as belonging to the genus Hoeflea, namely Hoeflea phototrophica; it showed a somewhat higher level of 16S rRNA gene sequence similarity with respect to strain AM1V30(T) (98.2 %) and was also taken into account. The fatty acid profiles, physiological and biochemical data and DNA G+C content (59.7 mol%) support the classification of strain AM1V30(T) as a member of the genus Hoeflea. The characteristics of the novel strain were sufficiently distinct to indicate that it represents a separate species. To confirm this conclusion, DNA-DNA hybridizations were performed: low values (between 15.8 and 29.8 %) were obtained in all cases. Thus, AM1V30(T) represents a novel species within the genus Hoeflea, for which the name Hoeflea alexandrii sp. nov. is proposed. Strain AM1V30(T) (=CECT 5682(T)=DSM 16655(T)) is the type strain.