Keratin waste has become an increasingly serious environmental and health hazard. Keratin waste is mainly composed of keratin protein, which is one of the most difficult polymers to break down in nature and is resistant to many physical, chemical, and biological agents. With physical and chemical methods being environment damaging and costly, microbial degradation of keratin using keratinase enzyme is of great significance as it is both environment friendly and cost-effective. The aim of this study was to extract and purify keratinase from bacterial species isolated from the soil. Among the organisms, an isolate of Bacillus velezensis, coded as MAMA could break down chicken feathers within 72 hours (h). The isolated strain produced significant levels of keratinase in mineral salt medium by supplying chicken feathers as the sole source of nitrogen and carbon. Feather deterioration was observed with the naked eye, and enzyme activity was evaluated using a spectrophotometric assay. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and zymography results revealed that the keratinase protein produced by Bacillus velezensis had a molecular weight between 40 and 55 kilo Dalton (kDa).
Incidental olfactory aplasia: a case reportWe report a case of olfactory aplasia with no other cerebral malformation in an elderly woman of high intellect.The patient was 73 years old and first presented at the age of 69 complaining of forgetfulness.On review by a neurologist at this time, history and examination were unremarkable apart from information volunteered by the patient her- self that she had never had any sense of smell.Neuropsychological testing was also per- formed with standard tests from the Wechsler Intelligence scale.The patient achieved a memory quotient well in excess of 143, which is the highest score in the published norms.Her pro-rated verbal and performance IQs were also in the high range at 134.She was admitted to the Alfred Hospital, Melbourne, in January 1992 after collapse.A cerebral CT scan showed an intracerebellar haemorrhage with extension of blood into the fourth, third, and lateral ventricles.She was taken to theatre where the blood clot was evacuated and a Rickham's reservoir was inserted.A postoperative cerebral digital subtraction angiogram revealed active bleeding from the left posterior infe- rior cerebellar artery.The patient then returned to theatre where a bleeding point was identified and trapped with two clips.She did not regain consciousness after the operation and showed no response to stan- dard stimuli.She died two days later.A postmortem of the brain only was per- formed.External examination showed normal facies and secondary sexual characteristics.An unexpected finding was that of absence of the olfactory bulbs and tracts (figure).This was associated with a deficiency of the falx cerebri anteriorly so that some of the medial frontal gyri of the right and left sides tended to interdigitate.The ventricular system was of normal configuration, however.There was extensive haemorrhagic necrosis of both cerebellar hemispheres, particularly the left, with upwards herniation bilaterally and mottled haemorrhagic necrosis of the mid-brain and pons.Review of the cerebral CT scan showed no detectable abnormalities of the skull.
Abstract Pseudomonas aeruginosa is one of the most antibiotic-resistant and opportunistic pathogens in immunocompromised and debilitated patients. It is considered the cause of most severe skin infections and is frequently found in hospital burn units. Due to its high antibiotic resistance, eliminating P. aeruginosa from skin infections is quite challenging. Therefore, this study aims to assess the novel in vitro antibacterial activity of methylene blue using a 635-nm diode laser to determine the effective power and energy densities for inhibition of P. aeruginosa . The strain was treated with various concentrations of methylene blue and 635-nm diode laser at powers of 300 mW/cm 2 and 250 mW/cm 2 . The diode laser’s potency in the photo-destruction of methylene blue and its degradation through P. aeruginosa were also evaluated. Colony-forming unit (CFU)/ml, fluorescence spectroscopy, optical density, and confocal microscopy were used to measure the bacterial killing effect. As a result, the significant decrease of P. aeruginosa was 2.15-log 10 , 2.71-log 10 , and 3.48-log 10 at 60, 75, and 90 J/cm 2 after excitation of MB for 240, 300, and 360 s at a power of 250 mW/cm 2 , respectively. However, a maximum decrease in CFU was observed by 2.54-log 10 at 72 J/cm 2 and 4.32-log 10 at 90 and 108 J/cm 2 after 300 mW/cm 2 of irradiation. Fluorescence images confirmed the elimination of bacteria and showed a high degree of photo-destruction compared to treatment with methylene blue and light alone. In conclusion, MB-induced aPDT demonstrated high efficacy, which could be a potential approach against drug-resistant pathogenic bacteria. Key points • Combination of methylene blue with 635-nm diode laser for antibacterial activity. • Methylene blue photosensitizer is employed as an alternative to antibiotics. • aPDT showed promising antibacterial activity against Pseudomonas aeruginosa.
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