新疆木蓼属新种

Atraphaxis jrtyschensis C. Y. Yang et Y. L. Han, sp.nov.     

Regulation of cell invasion and morphogenesis in a three-dimensional type I collagen matrix by membrane-type matrix metalloproteinases 1, 2, and 3

During tissue-invasive events, migrating cells penetrate type I collagen-rich interstitial tissues by mobilizing undefined proteolytic enzymes. To screen for members of the matrix metalloproteinase (MMP) family that mediate collagen-invasive activity, an in vitro model system was developed wherein MDCK cells were stably transfected to overexpress each of ten different MMPs that have been linked to matrix remodeling states. MDCK cells were then stimulated with scatter factor/hepatocyte growth factor (SF/HGF) to initiate invasion and tubulogenesis atop either type I collagen or interstitial stroma to determine the ability of MMPs to accelerate, modify, or disrupt morphogenic responses. Neither secreted collagenases (MMP-1 and MMP-13), gelatinases (gelatinase A or B), stromelysins (MMP-3 and MMP-11), or matrilysin (MMP-7) affected SF/HGF-induced responses. By contrast, the membrane-anchored metalloproteinases, membrane-type 1 MMP, membrane-type 2 MMP, and membrane-type 3 MMP (MT1-, MT2-, and MT3-MMP) each modified the morphogenic program. Of the three MT-MMPs tested, only MT1-MMP and MT2-MMP were able to directly confer invasion-incompetent cells with the ability to penetrate type I collagen matrices. MT-MMP-dependent invasion proceeded independently of proMMP-2 activation, but required the enzymes to be membrane-anchored to the cell surface. These findings demonstrate that MT-MMP-expressing cells can penetrate and remodel type I collagen-rich tissues by using membrane-anchored metalloproteinases as pericellular collagenases.     

Fungal keratitis in the State of Paraná-Brazil: clinical, epidemiological and diagnostic findings

Fungal keratites is more prevalent in tropical and subtropical regions, such as Brazil, and causes high morbidity. Usually, it is preceded by underlying conditions like ocular trauma or immunosuppression. The diagnosis is confirmed by the demonstration of the etiologic agent in the clinical specimen. Data were analysed from 49 patients with fungal keratitis observed in Ophthalmologic Division of Hospital de Clinicas, Federal University of Parana, from 1983 to 1997. The diagnosis was confirmed by culture and/ or direct examination. Of the cases studied, 22% were diagnosed only by direct examination; 50% by isolation in culture and 26% by the association of the both methods. The most prevalent etiologic agents were: Fusarium sp. (32%), Aspergillus sp. (16,5%) and Penicillium sp. (10%).     

The Synergistic Effect of Visible Light and Gentamycin on Pseudomona aeruginosa Microorganisms

Recently there were several publications on the bactericidal effect of visible light, most of them claiming that blue part of the spectrum (400 nm-500 nm) is responsible for killing various pathogens^1-5. The phototoxic effect of blue light was suggested to be a result of light-induced reactive oxygen species (ROS) formation by endogenous bacterial photosensitizers which mostly absorb light in the blue region^4,6,7. There are also reports of biocidal effect of red and near infra red⁸ as well as green light⁹.In the present study, we developed a method that allowed us to characterize the effect of high power green (wavelength of 532 nm) continuous (CW) and pulsed Q-switched (Q-S) light on Pseudomonas aeruginosa. Using this method we also studied the effect of green light combined with antibiotic treatment (gentamycin) on the bacteria viability. P. aeruginosa is a common noscomial opportunistic pathogen causing various diseases. The strain is fairly resistant to various antibiotics and contains many predicted AcrB/Mex-type RND multidrug efflux systems¹⁰.The method utilized free-living stationary phase Gram-negative bacteria (P. aeruginosa strain PAO1), grown in Luria Broth (LB) medium exposed to Q-switched and/or CW lasers with and without the addition of the antibiotic gentamycin. Cell viability was determined at different time points. The obtained results showed that laser treatment alone did not reduce cell viability compared to untreated control and that gentamycin treatment alone only resulted in a 0.5 log reduction in the viable count for P. aeruginosa. The combined laser and gentamycin treatment, however, resulted in a synergistic effect and the viability of P. aeruginosa was reduced by 8 log''s.The proposed method can further be implemented via the development of catheter like device capable of injecting an antibiotic solution into the infected organ while simultaneously illuminating the area with light.     

New sulfate-reducing bacteria isolated from Buryatian alkaline brackish lakes: description of Desulfonatronum buryatense sp. nov

New strains of sulfate-reducing bacteria were isolated from two alkaline brackish lakes located in the Siberian region of Russia, namely in the Southern Transbaikalia, Buriatia. The article presents data describing morphology, physiology, and biochemical characteristics of the isolated strains. These strains Ki4, Ki5, and Su2 were mesophilic and alkaliphilic with optimal growth at pH 8.9, 9.4, and 10.0, respectively. All isolated strains utilized lactate, formate, and ethanol in the presence of sulfate for growth and sulfidogenesis accompanied with formation of acetate and CO₂. Strains Ki5 and Su2 were able to reduce Fe(III). The DNA G + C content in strains Ki4, Ki5 and Su2 was 56.3, 48.8 and 59.6 mol%, respectively. According to phylogenetic analysis of 16S rRNA sequences, the new strains were clustered within the genus Desulfonatronum, and the closest relative D. lacustre Z-7951^T (=DSM 10312^T) showed 99.3–99.6 % similarity. DNA–DNA relatedness values of the strains Ki4, Ki5, and Su2 with D. lacustre Z-7951^T were 89, 53, and 79 %, respectively. Polyphasic taxonomy data suggest that strain Ki5^T is representative of the proposed novel species Desulfonatronum buryatense sp. nov.     

Profiling sterols in cerebrotendinous xanthomatosis: utility of Girard derivatization and high resolution exact mass LC-ESI-MS(n) analysis

In this study we profile free 3-oxo sterols present in plasma from patients affected with the neurodegenerative disorder of sterol and bile acid metabolism cerebrotendinous xanthomatosis (CTX), utilizing a combination of charge-tagging and LC-ESI-MS(n) performed with an LTQ-Orbitrap Discovery instrument. In addition, we profile sterols in plasma from 24-month-old cyp27A1 gene knockout mice lacking the enzyme defective in CTX. Charge-tagging was accomplished by reaction with cationic Girard's P (GP) reagent 1-(carboxymethyl) pyridinium chloride hydrazide, an approach uniquely suited to studying the 3-oxo sterols that accumulate in CTX, as Girard's reagent reacts with the sterol oxo moiety to form charged hydrazone derivatives. The ability to selectively generate GP-tagged 3-oxo-4-ene and 3-oxo-5(H) saturated plasma sterols enabled ESI-MS(n) analysis of these sterols in the presence of a large excess (3 orders of magnitude) of cholesterol. Often cholesterol detected in biological samples makes it challenging to quantify minor sterols, with cholesterol frequently removed prior to analysis. We derivatized plasma (10 μl) without SPE removal of cholesterol to ensure detection of all sterols present in plasma. We were able to measure 4-cholesten-3-one in plasma from untreated CTX patients (1207±302 ng/ml, mean±SD, n=4), as well as other intermediates in a proposed pathway to 5α-cholestanol. In addition, a number of bile acid precursors were identified in plasma using this technique. GP-tagged sterols were identified utilizing high resolution exact mass spectra (±5 ppm), as well as MS(2) ([M](+)→) spectra that possessed characteristic neutral loss of 79Da (pyridine) fragment ions, and MS(3) ([M](+)→[M-79](+)→) spectra that provided additional structurally informative fragment ions.