Reaz Mohammad Mazumdar

Nucleic acid amplification: Alternative methods of polymerase chain reaction.

Nucleic acid amplification is a valuable molecular tool not only in basic research but also in application oriented fields, such as clinical medicine development, infectious diseases diagnosis, gene cloning and industrial quality control. A comperehensive review of the literature on the principles, applications, challenges and prospects of different alternative methods of polymerase chain reaction (PCR) was performed. PCR was the first nucleic acid amplification method. With the advancement of research, a no of alternative nucleic acid amplification methods has been developed such as loop mediated isothermal amplification, nucleic acid sequence based amplification, strand displacement amplification, multiple displacement amplification. Most of the alternative methods are isothermal obviating the need for thermal cyclers. Though principles of most of the alternate methods are relatively complex than that of PCR, they offer better applicability and sensitivity in cases where PCR has limitations. Most of the alternate methods still have to prove themselves through extensive validation studies and are not available in commercial form; they pose the potentiality to be used as replacements of PCR. Continuous research is going on in different parts of the world to make these methods viable technically and economically.

Critical Factors Affecting the Success of Cloning, Expression, and Mass Production of Enzymes by Recombinant E. coli

E. coli is the most frequently used host for production of enzymes and other proteins by recombinant DNA technology. E. coli is preferable for its relative simplicity, inexpensive and fast high-density cultivation, well-known genetics, and large number of compatible molecular tools available. Despite all these advantages, expression and production of recombinant enzymes are not always successful and often result in insoluble and nonfunctional proteins. There are many factors that affect the success of cloning, expression, and mass production of enzymes by recombinant E. coli. In this paper, these critical factors and approaches to overcome these obstacles are summarized focusing controlled expression of target protein/enzyme in an unmodified form at industrial level.

Antibacterial, antifungal and antioxidant activities of the ethanol extract of the stem bark of Clausena heptaphylla

BackgroundThere is wide spread interest in drugs derived from plants as green medicine is believed to be safe and dependable, compared with costly synthetic drugs that have adverse effects.MethodsWe have attempted to evaluate the antioxidant, In vitro thrombolytic, antibacterial, antifungal and cytotoxic effects of Clausena heptaphylla (Rutaceae) stem bark extract ethanol extract.ResultsEthanolic stem bark extract of Clausena heptaphylla (CHET) contains flavonoids, alkaloids, saponins and steroids but it lacks tannins, anthraquinones and resins. Phenol content of the extract was 13.42 mg/g and flavonoid content was 68.9 mg/g. CHET exhibited significant DPPH free radical scavenging activity with IC50 value of 3.11 μg/ml. Reducing power of CHET was also moderately stronger. In the cytotoxicity assay, LC50 and Chi-square value of the ethanolic extract against brine shrimp nauplii were 144.1461 μg/ml and 0.8533 demonstrating potent cytotoxic effect of the extract. In vitro thrombolytic activity of CHET is significant with 45.38% clot lysis capability compared to that of Streptokinase (65.78%). In antibacterial screening, moderate zone of inhibition (6.5-9.0 mm in diameter) was observed against gram-positive Bacillus subtilis ATCC 11774, Bacillus cereus ATCC 10876, Staphylococcus aureus ATCC 25923, Bacillus polymyxa ATCC 842 and Bacillus megaterium ATCC 13578 and less promising zone of inhibition (3.0-4.5 mm in diameter) against gram-negative Salmonella typhi ATCC 65154, Shigella flexneri ATCC 12022, Proteus vulgaris ATCC 13315 and Escherichia coli ATCC 25922. Shigella sonnei ATCC 8992 did not show any sensitivity. The MIC values against these bacteria were ranged from 2,000 to 3,500 μg/ml. The extract showed significant zone of inhibition against Rhizopus oryzae DSM 2200, Aspergillus niger DSM 737 and Aspergillus ochraceus DSM 824 in antifungal assay.ConclusionsFurther advanced research is necessary to isolate and characterize the chemical components responsible for the therapeutic properties of the plant.

Anti-Bacterial Activity of Pigments Isolated From Pigment-Forming Soil Bacteria

Aims: Search for novel antimicrobials such as bacterial pigments is an issue of priority now. This study aims to isolate pigments with anti-bacterial activity from soil bacteria. Methodology: In this study, Pigment forming bacteria was isolated from soil samples collected from different sites of Dhaka city and its adjoining areas. Colonies of various colors such as yellow, golden yellow, red, pink, blue, green, purple and cream with both diffusible and non-diffusible pigments were isolated in pure cultures on nutrient agar plus 2 percent glycerol at pH 7.2 and 37oC. Anti-bacterial activity of the pigments extracted from the bacteria were determined. Results: 15 pigment forming bacteria was isolated from soil and identified to genus level as Pseudomonas, Flavobacterium, chromobacterium, Xanthomonas, Aeromonas, Escherichia and Bacillus. All the pigments showed to be broad spectrum in terms of inhibitory activity against all the pathogens included in this study. Most of the pigments Original Research Article British Journal of Pharmaceutical Research, 4(8): 880-894, 2014 881 showed better anti-bacterial activity against gram-negative bacteria. Highest zone of inhibition was resulted by pigment no 15 against Salmonella typhi and lowest zone of inhibition was observed for pigment 13 against Staphylococcus aureus. Most of the pigments except four (pigment no3, 10, 12, 15) were found to be bacteriostatic to the test pathogens. MIC value of the pigments ranged from 1500-4000 μg/ml and most of the pigments showed lower MIC value against gram-negative organisms. Conclusion: On the basis of anti-bacterial activity and minimum inhibitory concentration (MIC) pigment form Aeromonas (no6), Escherichia (no-10) and Pseudomonas (no-15) can be selected as effective anti-bacterial agent. Further studies are needed to use these pigments in food, cosmetic and textile industries.

Isolation, Identification, In Vitro Antibiotic Resistance and Plant Extract Sensitivity of Fire Blight Causing Erwinia amylovora

Background: Erwinia amylovora is the causal organism of fire blight. The fire blight is widely spread in bacterial disease of plants from both epidemiological and economic points of view. Furthermore, the situation is worsening by the advent of increased antibiotic resistance in these bacteria. The study was aimed to determine the in vitro antibiotic and herbal sensitivity of E. amylovora isolated from plants available in Sylhet, Bangladesh. Methods: In this study, bacterial isolates taken from five fire blight infected plants like apple, pear, lemon, orange and olive plants were identified based on morphological, cultural and biochemical characteristics. All the isolates were tested for antibiotic sensitivity against five commonly used antibiotics and herbal sensitivity against five plants extract. Results: Morphological, physiological and biochemical study of pure culture of suspected organism revealed E. amylovora bacteria which was found 100% resistant to Cefotaxime and 81.89% to Bacitracin. Chloramphenicol was found most effective as all the isolates were sensitive to it. Besides that, most of the isolates were susceptible to plant extracts and found maximum sensitive to Allium sativum and Syzygium cumini whereas resistant to V. amurensis. Conclusion: It can be concluded that the investigation of herbal treatment can be implicated for fire blight disease in contrast of antibiotic test in future.