Shakeel Ahmed Khan

Cellulase production from Aspergillus niger MS82: effect of temperature and pH

Fungal cellulases are well-studied enzymes and are used in various industrial processes. Much of the knowledge of enzymatic depolymerization of cellulosic material has come from Trichoderma cellulase system. Species of Trichoderma can produce substantial amounts of endoglucanase and exoglucanase but very low levels of b-glucosidase. This deficiency necessitates screening of fungi for cellulytic potential. A number of indigenously isolated fungi were screened for cellulytic potential. In the present study, the kinetics of cellulase production from an indigenous strain of Aspergillus niger MS82 is reported. Product formation parameters of endoglucanase and beta-glucosidase (Qp + Y(p/s)) indicate that A.niger MS82 is capable of producing moderate to high levels of both endoglucanase and beta-glucosidase when grown on different carbon containing natural substrates, for example, grass, corncob, bagasse along side purified celluloses. Furthermore, it was observed that the production of endoglucanase reaches its maximum during exponential phase of growth, while b-glucosidase during the Stationary phase. Enzyme production by solid-state fermentation was also investigated and found to be promising.Highest production of cellulase was noted at pH 4.0 at 35 degrees C under submerged conditions. Growth and enzyme production was affected by variations in temperature and pH.

Antibacterial and Antifungal Activities of Different Parts of Tagetes patula.: Preparation of Patuletin Derivatives

Abstract The current study evaluates the antibacterial and antifungal activities of extracts from different parts of Tagetes patula. Linn. (Asteraceae), reported for the first time in a single set of experiments. In the preliminary assay, the methanol extract of the flower (JFM) was found to possess antimicrobial activity against a number of bacteria with inhibition zone diameters ranging from 9 to 20 mm, the bioassay-guided fractionation of which led to the isolation of a flavonoid patuletin (3) in high yield as the active antibacterial principle with minimum inhibitory concentration (MIC) value of 12.5 μ g/disk against Corynebacterium. spp., Staphylococcus. spp., Streptococcus. spp., and Micrococcus luteus.. Its glucoside, patulitrin (4), was found to be weakly active, except against Staphylococcus saprophyticus., Streptococcus fecalis., and Streptococcus pyogenes. with inhibition zone diameters of 11, 16, and 12 mm, respectively. The cinnamate derivative (3b) of 3 showed antibacterial activity comparable with the parent flavonoid with a MIC value of 50 μ g/disk against Corynebacterium. spp., whereas benzoate derivative (3a) was found to be devoid of any activity; both the derivatives are new compounds. Moreover, the long-chain alcohol 5, which displayed antibacterial activity in the preliminary testing, was obtained in large quantity directly from the petroleum ether extract of the involucre of the flowers.

Production of plant cell wall degrading enzymes by monoculture and co-culture of Aspergillus niger and Aspergillus terreus under SSF of banana peels

Filamentous fungi are considered to be the most important group of microorganisms for the production of plant cell wall degrading enzymes (CWDE), in solid state fermentations. In this study, two fungal strains Aspergillus niger MS23 and Aspergillus terreus MS105 were screened for plant CWDE such as amylase, pectinase, xylanase and cellulases (β-glucosidase, endoglucanase and filterpaperase) using a novel substrate, Banana Peels (BP) for SSF process. This is the first study, to the best of our knowledge, to use BP as SSF substrate for plant CWDE production by co-culture of fungal strains. The titers of pectinase were significantly improved in co-culture compared to mono-culture. Furthermore, the enzyme preparations obtained from monoculture and co-culture were used to study the hydrolysis of BP along with some crude and purified substrates. It was observed that the enzymatic hydrolysis of different crude and purified substrates accomplished after 26 h of incubation, where pectin was maximally hydrolyzed by the enzyme preparations of mono and co-culture. Along with purified substrates, crude materials were also proved to be efficiently degraded by the cocktail of the CWDE. These results demonstrated that banana peels may be a potential substrate in solid-state fermentation for the production of plant cell wall degrading enzymes to be used for improving various biotechnological and industrial processes.

Effect of cream containing Melia azedarach flowers on skin diseases in children

A herbal cream containing a methanolic HPLC-standardized extract of Melia azedarach flowers has been prepared and found potent against bacterial skin diseases like cellulitis, pustules, pyogenic infections, etc. in children. The results obtained are comparable to those with neomycin.

The effect of pH and temperature on haemolysin production by Listeria species

The ability of three strains of Listeria monocytogenes NCTC 7973, serovar 1 2a, NCTC 5124m serovar 4a, C‐274 serovar 4b and one strain of L. seeligeri (SLCC 3954) to grow in TPB (Tryptose phosphate agar) at pH values between 5–9 and produce haemolysin has been investigated at two incubation temperatures. The minimum and maximum pH values at which haemolysin was detected were 5 and 9 respectively, at 20° and 32°C.

Molecular Characterization of Pakistani Field Isolates of Infectious Bursal Disease Virus

Abstract The reverse transcriptase-polymerase chain reaction followed by restriction fragment length polymorphism (RT-PCR/RFLP) technique was used to identify and characterize Pakistani field isolates of infectious bursal disease virus (IBDV). These isolates have caused heavy losses to the poultry industry (mortality up to 60%) during the period between 1999 and 2005. Ten samples (five local isolates and five commercial vaccines) were examined for IBDV. Nine samples were positive for IBDV as evidenced by the amplification of the 743-bp region of the VP2 gene by RT-PCR. The RT-PCR products were subjected to restriction enzyme digestion with BstNI, MboI, and SspI. The RFLP profiles of all samples on digestion with the MboI enzyme yielded a fragment size of 229 and 362 bp except for vaccine strain Bursine Plus, which yielded a profile of 229 and 480 bp. However, digestion with BstNI yielded two distinct RFLP patterns. The first profile was detected in field isolates ML-1/SPVC/2001 and NP2/SPVC/2002 with four fragments of 119, 154, 172, and 209 bp, resembling RFLP profiles of molecular group 4 isolates. NL-3/SPVC/2003, NK-4/SPVC/2004, and NPK-5/SPVC/2005 generated a different RFLP profile with fragments of 119, 172, and 424 bp, resembling the profiles of molecular group 6 isolates. However, all the field and vaccine strains showed the absence of SspI restriction sites in their genome. It can be concluded that the Pakistani isolates can be grouped in molecular groups 4 and 6 of IBDV.