Isolation and Characterization of A Metal-resistant Pseudomonas Aeruginosa Strain

Summary The use of microorganisms to remove heavy metals from industrial effluent is an area of extensive research and development. Attempts have been made to isolate and characterize metal-resistant microorganisms from treated oil mill industry effluent wastewater samples. The metal-resistant organisms that showed values of minimum inhibitory concentration towards metals (Cd, Cr, Ni and Pb) ranging from 100 to 800 ppm level were screened. A potent metal-resistant organism, isolate BC15 from the wastewater samples was tentatively identified as Pseudomonas sp. Detailed analysis of morphological, biochemical and 16S rDNA sequence of the isolate revealed that it is closely related to Pseudomonas aeruginosa (94%). Pseudomonas BC15 was capable of absorbing 93% Ni, 65% Pb, 50% Cd and 30% Cr within 48 h from the medium containing 100 mg of each heavy metal per liter. The multiple metal tolerance of this strain was also associated with resistance to antibiotics such as ampicillin, tetracycline, chloramphenicol, erythromycin, kanamycin and streptomycin.     

Synthesis and antibacterial property of quinolines with potent DNA gyrase activity

Synthesis of a series of novel tetrahydroquinoline annulated heterocycles has been accomplished by intramolecular imino and bisimino Diels–Alder reaction. These compounds were evaluated for their antibacterial activity. All the synthetic compounds, exhibited good antibacterial activity against microorganisms of which one of them 7 was found to be as active as the antibiotic ciplofloxacin and is found to have MIC value of 2.5 mg/mL against Escherichia coli.     

Production and characterization of haloalkaline protease from ascidian-associated <Emphasis Type="Italic">Virgibacillus halodenitrificans</Emphasis> RSK CAS1 using marine wastes

A marine ascidian-associated bacterium, Virgibacillus halodenitrificans RSK CAS1, was optimized for protease production by response surface methodology using marine waste as substrate. The central composite design was employed, and the optimal medium constituents for maximum protease production (1461.11 U/ml) were determined to be shrimp shell powder (15.32 g/l), casein (5.37 g/l), MgSO₄ (3.0 g/l) and NaCl (55.31 g/l). The protease was purified from the culture supernatant to homogeneity in a three-step procedure consisting of ammonium sulfate precipitation, ion exchange chromatography (DEAE-cellulose column) and gel-filtration chromatography (Sephadex G-75 column), resulting in a 8.7-fold-change in purified protein. This protein had a specific activity of 1,086.78 U/mg and a molecular weight of 21 kDa. It exhibited optimal activity at 50 °C, pH 9 and 25 % NaCl. The significant stability of this protein at higher levels of salt, metal ions, organic solvents and commercial detergents and at higher, temperature, as well as its application as a cleaning additive in blood stain removal, suggests its possible use the laundry detergent industry.     

Molecular docking analysis of flavonoids with aldose reductase

Diabetes mellitus is a group of metabolic disorders that has risen to become the third most common cause in humans in recent years. The development of new bioactive substances from natural sources is a relatively new area. Flavonoids are believed to have a variety of beneficial properties in nature, including anti-inflammatory, antimicrobial, anticancer, antioxidant, neuroprotective, and anti-HIV properties. 15 naturally occurring flavonoids docked with the selected target aldose reductase. We report the optimal binding of Acumitin, Agathisflavone, Agehoustin B, and alpha-Toxicarol with aldose reductase for further consideration in drug discovery for T2DM.     

Brevibacterium frigoritolerans a novel entomopathogen of Anomala dimidiata and Holotrichia longipennis (Scarabaeidae: Coleoptera)

We describe the isolation, biochemical characterization, phylogenetic analysis, and pathogenecity of a novel entomopathogenic bacterium Brevibacterium frigoritolerans to first instar larvae of Anomala dimidiata and Holotrichia longipennis. The almost full length 16S rRNA sequence of the bacterium has 99% identity with the type strain of B. frigoritolerans, while phylogenetic analysis revealed that the isolate formed a tightly linked branch with the type strain of B. frigoritolerans. Under in vitro bioassay conditions, the isolate infected and caused 89±5.4 and 74±7.7% mortality, in first instar larvae of A. dimidiata and H. longipennis, respectively. The infected larvae exhibited bacteremia like symptoms and mortality occurred between the second and fifth weeks after inoculation. This is an early report on the entomopathogenic potential of the hitherto lesser-known bacterium Brevibacterium frigoritolerans.     

Development of humanized antibodies as cancer therapeutics

Recent success in the development of monoclonal antibody-based anti-cancer drugs has largely benefitted from the advancements made in recombinant technologies and cell culture production. These reagents, derived from the antibodies of mouse origin, while maintaining the exquisite specificity and affinity to the tumor antigens, have low immunogenicity and toxicity in human. High-level expressing cell clones are generated and used to produce large quantities of the recombinant antibodies in bioreactors in order to meet the clinical demand for therapeutic applications. In this report, the systems and general methodologies developed by us to construct and produce humanized antibodies from the parent mouse antibodies are described. Once the humanized antibodies are available, they can be applied in three principal forms for cancer therapy: (1) naked antibodies, (2) drug- or toxin conjugates, and (3) radioconjugates. Using the humanized anti-CD22 (epratuzumab) and anti-carcinoembryonic antigen (ant-CEA; labetuzumab) antibody prototypes, clinical applications of naked and radiolabeled humanized monoclonal antibodies are described.     

Genomic DNA Amplification from a Single Bacterium

Genomic DNA was amplified about 5 billion-fold from single, flow-sorted bacterial cells by the multiple displacement amplification (MDA) reaction, using 29 DNA polymerase. A 662-bp segment of the 16S rRNA gene could be accurately sequenced from the amplified DNA. MDA methods enable new strategies for studying nonculturable microorganisms.     

Modulated phases of phospholipid bilayers induced by tocopherols

The influence of α-, γ- and δ-tocopherols on the structure and phase behavior of dipalmitoyl phosphatidylcholine (DPPC) bilayers has been determined from X-ray diffraction studies on oriented multilayers. In all the three cases the main-transition temperature (T(m)) of DPPC was found to decrease with increasing tocopherol concentration up to around 25 mol%. Beyond this the main transition is suppressed in the case of γ-tocopherol, whereas T(m) becomes insensitive to composition in the other two cases. The pre-transition is found to be suppressed over a narrow tocopherol concentration range between 7.5 and 10 mol% in DPPC-γ-tocopherol and DPPC-δ-tocopherol bilayers, and the ripple phase occurs down to the lowest temperature studied. In all the three cases a modulated phase is observed above a tocopherol concentration of about 10 mol%, which is similar to the P(β) phase reported in DPPC-cholesterol bilayers. This phase is found to occur even in excess water conditions at lower tocopherol concentrations, and consists of bilayers with periodic height modulation. These results indicate the ability of tocopherols to induce local curvature in membranes, which could be important for some of their biological functions.     

Spectral Analysis of Naturally Occurring Methylxanthines (Theophylline,Theobromine and Caffeine) Binding with DNA

Nucleic acids exist in a dynamic equilibrium with a number of molecules that constantly interact with them and regulate the cellular activities. The inherent nature of the structure and conformational integrity of these macromolecules can lead to altered biological activity through proper targeting of nucleic acids binding ligands or drug molecules. We studied the interaction of naturally occurring methylxanthines such as theophylline, theobromine and caffeine with DNA, using UV absorption and Fourier transform infrared (FTIR) spectroscopic methods, and especially monitored their binding affinity in the presence of Mg²⁺ and during helix-coil transitions of DNA by temperature (T_m) or pH melting profiles. The study indicates that all these molecules effectively bind to DNA in a dose dependent manner. The overall binding constants of DNA-theophylline = 3.5×10³ M⁻¹, DNA-theobromine = 1.1×10³ M⁻¹, and DNA-Caffeine = 3.8×10³ M⁻¹. On the other hand T_m/pH melting profiles showed 24–35% of enhanced binding activity of methylxanthines during helix-coil transitions of DNA rather than to its native double helical structure. The FTIR analysis divulged that theophylline, theobromine and caffeine interact with all the base pairs of DNA (A-T; G-C) and phosphate group through hydrogen bond (H-bond) interaction. In the presence of Mg²⁺, methylxanthines altered the structure of DNA from B to A-family. However, the B-family structure of DNA remained unaltered in DNA-methylxanthines complexes or in the absence of Mg²⁺. The spectral analyses indicated the order of binding affinity as “caffeine≥theophylline>theobromine” to the native double helical DNA, and “theophylline≥theobromine>caffeine to the denatured form of DNA and in the presence of divalent metal ions.