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Clear Zone (clear + zone)
Selected AbstractsEvolution of histoid leprosy (de novo) in lepromatous (multibacillary) leprosyINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 7 2005Virendra N. Sehgal MD A 26-year-old man presented with persistent redness of the face over the past 2 years and thickening of the ears for a year. The current state was preceded by three to four episodes of epistaxis, 2,3 months previously. The patient had not received any treatment. Cutaneous examination revealed indurated (infiltrated) plaques on the face and ears over an apparently normal-looking skin, and numerous, small, ill-defined, slightly hypopigmented, shiny macules all over the body. They were bilateral and symmetric (Fig. 1a,b). There was no variation in the cutaneous sensations of temperature, touch, and pain. The patient showed loss of the lateral eyebrows and conjunctival congestion. Examination of the nerves revealed enlargement of the ulnar, radial, posterior tibial, and right common peroneal nerves; however, there was no tenderness of the nerves. Systemic examination was within normal limits. Examination of a slit-skin smear (under oil immersion), prepared from a representative lesion (plaque), demonstrated an abundance of solid and uniform-staining acid-fast bacilli, occurring either singly or in parallel clumps/globii, in an average field (6+). Furthermore, a scraping mount (10% KOH) prepared from the lesion on the back was negative. Figure 1. (a, b) Histoid leprosy Hematoxylin and eosin-stained sections prepared from a biopsy taken from a plaque revealed a conspicuous granuloma composed of peculiar spindle-shaped histiocytes. Several of the granulomas were present in the mid and lower dermis. They were characterized by whorled, criss-cross, or parallel patterns. Solid and uniform-staining, slender, rod-like (length three times that of the breadth) acid-fast bacilli were found scattered throughout the section. A few histiocytes closely packed with acid-fast bacilli, together with lymphocytic infiltrates, were also seen. There was a prominent eosinophilic stained clear zone just below the epidermis. It was free from acid-fast bacilli as well as the inflammatory infiltrate (Fig. 2a,b). A definitive diagnosis of untreated lepromatous leprosy (LL) changing to histoid leprosy (de novo) was made. Figure 2. (a, b) Histoid leprosy depicting granuloma formed by histiocytes displaying whorl-wind, criss-cross or interlacing pattern, and a clear zone beneath the epidermis (H&E ×40) Solid and uniform staining acid fast bacilli, , slender, rod-like, length 3 times that of breadth found scattered throughout the granuloma (H&E ×100) [source] Purification and molecular characterization of subtilisin-like alkaline protease BPP-A from Bacillus pumilus strain MS-1LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2006T. Miyaji Abstract Aims:, The present study was conducted by screening zein-degrading bacteria in an attempt to obtain zein-degrading protease. Methods and Results:, Soil bacteria were screened by formation of a clear zone on zein plates. Characterization of a zein-degrading bacterium indicated a taxonomic affiliation to Bacillus pumilus, and was named MS-1 strain. The strain produced two different types of extracellular proteases, BPP-A and BPP-B. In this study, we purified and characterized BPP-A because it exhibited a higher ability to hydrolyze zein than BPP-B. When casein was used as the substrate, the optimal pH for BPP-A was 11ˇ0. In BPP-A, zein was better substrate than casein at pH 13ˇ0, whereas casein was better one than zein at pH 11ˇ0. The bppA gene encoded a 383-amino acid pre-pro form of BPP-A, and mature BPP-A contained 275 amino acid residues. It was concluded that BPP-A belonged to the subtilisin family. Conclusion:, A zein-degrading bacterium assigned to B. pumilus produced two different types of extracellular proteases, BPP-A and BPP-B. BPP-A exhibited an ability to hydrolyze zein in an extreme alkaline condition. Significance and Impact of the Study:, This is a first report on screening for zein-degrading micro-organisms. The subtilisin-like protease BPP-A is possible to utilize as an industrial enzyme for the production of zein hydrolysates. [source] Cellular effects of monohydrochloride of l -arginine, N, -lauroyl ethylester (LAE) on exposure to Salmonella typhimurium and Staphylococcus aureusJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2004E. Rodríguez Abstract Aims:, Here we study the effect of monohydrochloride of l -arginine, N, -lauroyl ethylester (LAE), a cationic preservative derived from lauric acid and arginine, on the cell envelopes of Salmonella typhimurium and Staphylococcus aureus at sub-lethal concentration such as their respective minimal inhibitory concentrations, 32 and 8 ,g ml,1, respectively. Methods and Results:, Bacterial populations were studied by using transmission electron and fluorescence microscopy (TEM and FM), flow cytometry (FC) and ion-flux across the cellular membrane. Cell integrity was altered mainly in the outer membrane of S. typhimurium, but there was no significant change in the cytoplasm. However, in Staph. aureus, clear zones, abnormal septation and mesosome-like structures were observed in the cytoplasm. Bacterial populations were double-stained with propidium iodide (PI) and SYTO-13 for FC analysis. In S. typhimurium the proportion of damaged cells after 24 h was 97% and in Staph. aureus 56ˇ3%. LAE induced transmembrane ion flux, the increase of potassium leakage after 30 min of contact was 7ˇ7 and 3ˇ34 ,g ml,1 for Staph. aureus and S. typhimurium, respectively. Membrane disruption was detected by measuring the proton flow across the membrane. Conclusions:, Disturbance in membrane potential and structural changes was caused by LAE, although cells were not disrupted. Significance and Impact of the Study:, This is the first time the cellular effects of LAE on bacterial cells were studied. [source] | ||||||||||