Habib Nasir

The hydroxylation of testosterone and some relatives by Cephalosporium aphidicola

Abstract The fungus Cephalosporium aphidicola has been shown to hydroxylate testosterone, 19-nortestosterone, 1-dehydrotestosterone, 1α-methyltestosterone, androst-4-en-3-one, androst-4-en-3,17-dione and 17α-methyltestosterone predominantly at the C-6β position with a minor hydroxylation occurring at the C-14α position. 19-Nortestosterone was also hydroxylated at the C-10β position. In contrast to the hydroxylation of progesterone by this organism, hydroxylation at C-11α was a minor pathway.

The biotransformation of some steroids by Cephalosporium aphidicola

Abstract Hydroxylation of 5α-androstan-3-one and 3,6-dione by C. aphidicola takes place at C-17β and, in the case of the latter, at C-5α. The fungus reduces 5α-androstan-17-one and the 3,17-dione to the 17β-alcohols.

Cefazolin loaded chitosan nanoparticles to cure multi drug resistant Gram-negative pathogens

Antibiotic resistance against Gram-negative microbes is considered as an alarming phenomenon that needs to be addressed urgently to develop better therapeutic solutions. The aim of the present research work was to investigate and develop cefazolin loaded chitosan nanoparticles (CSNPs) as a potential tool against multidrug resistant pathogens. Empty and drug loaded CSNPs were prepared by ionic gelation method. It was observed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) based studies that CSNPs were less than 100 nm in size and displayed homogeneity both in shape and size. Encapsulation of cefazolin has not increased the size of nano systems. Zeta sizer results revealed that both systems have positive zeta potential of more or less +50 mV, thus contributing towards a stable formulation. Encapsulation efficiency was directly proportional to the increase in the concentration of antibiotic (28-62%). Furthermore, growth kinetics study had demonstrated excellent antimicrobial potential of cefazolin loaded CSNPs against multi drug resistant Klebsiella pneumoniae, Pseudomonas aeroginosa and Extended Spectrum Beta Lactamase (ESBL) positive Escherichia coli.

Biotransformation of the sesquiterpenoid, cedrol, by Cephalosporium aphidicola

Abstract In studies directed at examining the scope of biosynthetically directed biotransformations by Cephalosporium aphidicola , the sesquiterpenoid, cedrol, has been shown to be hydroxylated primarily at C-3.

Distribution, toxicity level, and concentration of polycyclic aromatic hydrocarbons (PAHs) in surface soil and groundwater of Rawalpindi, Pakistan

Abstract In this study, the distribution, toxicity level, and relationship of polycyclic aromatic hydrocarbons (PAHs) with total organic content (TOC) have been investigated using surface soil and ground water samples from an area adjacent to petrochemical plant in Pakistan. Six PAHs, naphthalene, acenaphthene, phenanthrene, anthracene, flouranthene, and chrysene, were selected from the 16 Environment Protection Agency priority pollutants list. ΣPAHs range from 2,700 to 4,443 μg/g (average: 3,672 ± 592 μg/g) in soil and 201–1,634 ng/L (average: 763 ± 377 ng/L) in water. The compositional profile of PAHs revealed that low molecular weight 3–4 ring PAHs were predominant. The ratios of phenanthrene/anthracene reflected the pyrogenic origin of PAHs. The relationship of PAHs with TOC has also been investigated and a positive correlation was observed between ΣPAHs and TOC. This indicates that partitioned in organic matter may be the possible source of PAHs in water. An assessment using widely cited guidelines i...

Development of Cefotaxime Impregnated Chitosan as Nano-antibiotics: De Novo Strategy to Combat Biofilm Forming Multi-drug Resistant Pathogens.

Frequent incidents of antibiotic-resistant biofilm forming pathogens in community-associated and hospital-acquired infections have become a global concern owing to failure of conventional therapies. Nano-antibiotics (NABs) are de novo tools to overcome the multi-drug resistant mechanisms employed by the superbugs. Inhibition of biofilm formation is one of those strategies to curb multi drug resistance phenomenon. In the current study, the anti-biofilm and antibacterial potential of newly synthesized cefotaxime loaded chitosan based NABs have been investigated. Both bare and cefotaxime loaded NABs were prepared by ionotropic gelation method. They were found carrying positive zeta potential of more than +50 mV, indicating highly stable nano-dispersion. Moreover, microscopic studies revealed their size as less than 100 nm. NABs were tested against clinical isolates of multi drug resistant Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and methicillin resistant Staphylococcus aureus and wherein they demonstrated broad-spectrum anti-biofilm and anti-pathogenic activity. Thus, in vitro synergistic action of cephalosporin drugs and chitosan polymer at nano-scale in contrast to free antibiotics can be an improved broad-spectrum strategy to thwart resistance mechanisms in both Gram-positive and Gram-negative resistant pathogens.

Cleaner production technologies in desizing of cotton fabric

Desizing is one of the key processes for the pretreatment of cotton fabric wet processing. Prior to dyeing and printing, it is essential to remove the sizes coated on fabric. Cleaner production technologies, using which hazardous material is substituted with -amylase, an eco-friendly material, are applied for desizing of cotton fabric. The enzymatic desizing process is human-, machine-, and environmentally-friendly. Four different types of machines were used to investigate the aspects and results of enzymatic desizing. Unlike acid and oxidative desizing, biodegradation of sizes does not damage fabric and emit greenhouse gases (CO2), respectively. The highest quality of desizing was observed by using winch technology. The degree of desizing on TEGEWA scale was 8. The amount of desizing agent used was 0.5–4.0 kg/1000 liters. In winch (batch) desizing, the degree of whiteness was 76%, which is 1.5 times higher than grey fabric, but pad steam (continuous) desizing process showed 69% degree of whiteness, which is 1.35 times higher than grey fabric. The competitive results were achieved in continuous process with efficient time. This article reveals the benefits, processes and results of eco-friendly technology within the framework of textile wet process industry.

The biotransformation of 8-epicedrol and some relatives by Cephalosporium aphidicola

The microbiological hydroxylation of 8-epicedrol and relatives bearing hydroxyl groups at C-9 and C-15 by Cephalosporium aphidicola has been shown to take place predominantly at C-3.

Two non-nitrogenous triterpenoids from roots of Buxus papillosa

Abstract Two new non-nitrogenous triterpenoids have been isolated from the roots of Buxus papillosa . They were characterized as 11α-hydroxy-4,4,14-trimethyl-9β,19-cyclo-5α-androst-1-ene-3,17-dione (11α-hydroxybuxatenone) and methyl 4-hydroxy-4,4,14-trimethyl-17-oxo-9(10→19) abeo -3,4-seco-5α-androsta-1(10),9(11)-dien-3-oate(buxahejrine) by extensive analysis of the spectral data.

The biotransformation of the diterpenoid, sclareol, by Cephalosporium aphidicola

Abstract The biosynthetically directed microbiological transformation of the diterpenoid sclareol by the fungus, Cephalosporium aphidicola , has been shown to involve oxidation at C-3, C-14 and C-18.