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2.
Food Chem ; 441: 138362, 2024 May 30.
Article in English | MEDLINE | ID: mdl-38219362

ABSTRACT

This Schiff base chemosensor (SNN) detected dual ions, Al3+ and Zn2+ ions selectively. Fluorescence spectrum investigations showed that Al3+ ions increased fluorescence intensity, notably at 493 nm. Introducing Zn2+ ions caused a significant blue shift of roughly ∼65 nm at a wavelength of 434 nm, resulting in a notable change in fluorescence intensity. When binding Al3+/Zn2+ ions, the SNN receptor uses three methods. Inhibition of photoinduced electron transfer (PET), excited state intramolecular proton transfer (ESIPT), and restriction of CN isomerization. The jobs plot method found that SNN + Al3+ and SNN + Zn2+ complexations had a 1:1 stoichiometry. DFT, LC-HRMS, and 1H NMR titration confirm this conclusion. The probe SNN's limit of detection (LOD) for Al3+/Zn2+ ions was 3.99 nM and 1.33 nM. Latent fingerprint (LFP), food samples, pharmaceutical products, and E. coli pathogen bio-imaging have all used the SNN probe to identify Al3+ and Zn2+ ions.


Subject(s)
Aldehydes , Escherichia coli , Fluorescent Dyes , Fluorescent Dyes/chemistry , Ions , Protons , Zinc/analysis , Spectrometry, Fluorescence/methods
3.
J Vector Borne Dis ; 59(3): 246-252, 2022.
Article in English | MEDLINE | ID: mdl-36511041

ABSTRACT

BACKGROUND & OBJECTIVES: Bacillus subtilis subsp. subtilis (VCRC B471) and Pseudomonas fluorescens (B426) produce mosquitocidal biosurfactant, surfactin and di-rhamnolipid. The objective of the study was to carry out a small-scale field evaluation of the two biosurfactants to determine the efficacy, application dosage, residual activity and frequency of application against Anopheles stephensi immatures in selected sites in Goa, India. METHODS: Surfactin (VCRC B471) and di-rhamnolipid (VCRC B426) were formulated as aqueous suspensions (5% AS), and were applied at the dosages of 34, 51 and 68 mL/m2 and 27, 41 and 54 mL/m2 respectively. Two experiments were carried out with the two formulations. RESULTS: Surfactin (VCRC B471) formulation was effective at all the dosages and there was sustained reduction (>80%) in immature density in the treated sites up to 18 days in experiment 1 and up to 15 days in experiment 2. No pupae were found in the treated sites throughout the study. Di-rhamnolipid (VCRC B426) formulation was also found to reduce the immature density in the treated sites up to 14 days in experiment 1 and up to 15 days in experiment 2. INTERPRETATION & CONCLUSION: For VCRC B471, the optimum application dosage determined was 51 mL/m2 and for VCRC B426, 27mL/m2. The formulations are to be applied fortnightly for effective control of Anopheles. The application dosage determined in the present study can be used for large scale field evaluation to assess their suitability for use in public health programmes for the control of Anopheles mosquitoes vectoring malaria.


Subject(s)
Anopheles , Malaria , Pseudomonas fluorescens , Animals , Humans , Malaria/prevention & control , Mosquito Vectors , Bacillus subtilis
4.
Food Chem ; 395: 133617, 2022 Nov 30.
Article in English | MEDLINE | ID: mdl-35802967

ABSTRACT

Dimeric quinoline-based Schiff base was developed (DQS) for the specific detection of Pb2+ ion via fluorimetry. DQS coordinates with Pb2+, a variation in fluorescence intensity with enhanced radical blue shift was observed due to the restriction of CN rotation, CN isomerization, and photoinduced electron transfer (PET) mechanisms. In addition, the intramolecular charge transfer (ICT) from electron-donating morpholine to phenylene diamine acceptor linked quinoline bridge is responsible for the blue-shifted fluorescence enhancement in the DQS-Pb2+ complex. The binding stoichiometry of DQS: Pb2+ (1:2) was confirmed by host-guest titration and mass spectrometry. The limit of detection (LOD) of the DQS was found to be 1.3 × 10-7 M for Pb2+ ion. The DQS sensing ability of Pb2+ was further applied into milk and honey samples, smartphone, bio-imaging and to construct of an INHIBIT molecular logic gate.


Subject(s)
Honey , Quinolines , Fluorescent Dyes/chemistry , Lead , Quinolines/chemistry , Smartphone , Spectrometry, Fluorescence/methods
5.
Food Chem ; 348: 129098, 2021 Jun 30.
Article in English | MEDLINE | ID: mdl-33515942

ABSTRACT

We report the modular design and synthesis of an amine dangled Schiff base quinoline-morpholine conjugate (QMC) for highly selective detection of Pb2+ ions via fluorimetry. The sensing strategy of QMC towards Pb2+ ion exhibits a large blue shift with fluorescent enhancement via the intramolecular charge transfer (ICT) process. At the same time, QMC coordination with Pb2+, the CN single bond rotation between quinoline and morpholine rings and the CN isomerization process were blocked. Best of our knowledge, this is the first blue shifted turn-on fluorescent chemosensor for Pb2+ ion via the ICT process. Furthermore, QMC selectively detects Pb2+ ion without any interference with alkali, alkaline earth, and transition metal ions, and limit of detection (LOD) downs to 13 µM, which is a permissible level of Pb2+ ion in drinking water reported by WHO. The 1:2 binding stoichiometry between QMC and Pb2+ was confirmed by fluorimetric, 1H NMR titration, mass spectrometry, and theoretical studies. Finally, QMC was potentially applied for the sensing of Pb2+ ions in milk, red wine, live cells and an INHIBIT molecular logic function was constructed by using Pb2+ and EDTA as chemical inputs.


Subject(s)
Fluorescent Dyes/chemistry , Logic , Milk/chemistry , Molecular Imaging/methods , Quinolines/chemistry , Animals , Lead/analysis , Lead/chemistry , Limit of Detection , Schiff Bases/chemistry , Spectrometry, Fluorescence
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 246: 119018, 2021 Feb 05.
Article in English | MEDLINE | ID: mdl-33096446

ABSTRACT

A simple hydroxyl-substituted triphenyl-imidazole based receptor (HTPI) which selectively detects Cu2+ ion by colorimetric and fluorimetric methods was developed. HTPI detects the Cu2+ ions with the absorption enhancement and fluorescence quenching by the possible ligand to metal charge transfer (LMCT) and the chelation-enhanced quenching (CHEQ) approaches, respectively. HTPI showed high selectivity and sensitivity for Cu2+ ions detection over other interfering and competing metal ions. Interestingly, HTPI detects Cu2+ ion (LOD) at nanomolar concentrations (19 × 10-9 M (UV-vis) & 27 × 10-9 M (fluorescence), respectively), which is lower than the permissible level of Cu2+ ion reported by World Health Organization (WHO). Furthermore, HTPI was applied to the molecular logic gate function by using chemical inputs, and Cu2+ ion was potentially removed (95%) via Capacitive Deionization technique.

7.
Acta Trop ; 148: 24-31, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25912083

ABSTRACT

Pseudomonas fluorescens Migula (VCRC B426) produces a secondary metabolite, which was found to be active against pupae of vector mosquitoes namely Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti. The mosquito pupicidal metabolite from P. fluoescens was mass produced and separated by ethyl acetate extraction and purified further by silica gel column chromatography, FPLC, HPLC and TLC. The purified metabolite was characterized by NMR, FT-IR, LC-MS and MALDI-TOF. The FT-IR, (1)H and (13)C NMR results showed that it is a rhamnolipid (di-rhamnolipid). The matrix assisted laser desorption and ionization-time-of-flight spectrum of the sample showed predominant pupicidal component produced by P. fluorescens was the molecule mass of 673.40 Da. Owing to its high toxicity to mosquito pupae, especially Anopheles sp., and Aedes sp., the di-rhamnolipd has potential in the control of the vectors of dengue, chikungunya, yellow fever and malaria. This is the first report of mosquito pupicidal di-rhamnolipid from P. fluorescens.


Subject(s)
Culicidae/drug effects , Glycolipids/pharmacology , Insecticides/pharmacology , Pseudomonas fluorescens/metabolism , Aedes/drug effects , Animals , Anopheles/drug effects , Culex/drug effects , Glycolipids/chemistry , Insecticides/chemistry , Pest Control, Biological , Pupa/drug effects , Spectroscopy, Fourier Transform Infrared
8.
Acta Trop ; 120(3): 155-9, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21810402

ABSTRACT

Samples collected from the mangrove forests of Andaman & Nicobar islands yielded a mosquitocidal bacterium, whose extracellular metabolite(s) exhibited mosquito larvicidal and pupicidal activity. The bacterium was isolated using standard microbiological methods and identified using classical biochemical tests and rpoB gene sequences. The mosquitocidal bacterium was identified as Bacillus amyloliquefaciens. Mosquitocidal metabolite(s) was separated from the culture supernatant of the bacterium and its efficacy against the larval and pupal stages of different species of mosquitoes was determined in terms of LC(50) and LC(90). Mosquito larvicidal activity in terms of LC(50) against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti was respectively, 26.4µg, 22.2µg and 20.5µg/ml and its pupicidal activity was 4.4µg, 8.2µg and 14.5µg/ml respectively. The mosquitocidal metabolite(s) was found to be a biosurfactant. This is the first report of the mosquitocidal activity of B. amyloliquefaciens and it is a new weapon which can be added to the array of microbial agents for use against mosquitoes.


Subject(s)
Aedes/drug effects , Anopheles/drug effects , Bacillus/metabolism , Culex/drug effects , Environmental Microbiology , Insecticides/metabolism , Aedes/growth & development , Animals , Anopheles/growth & development , Bacillus/classification , Bacillus/genetics , Bacillus/isolation & purification , Bacterial Typing Techniques , Culex/growth & development , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA-Directed RNA Polymerases/genetics , India , Insecticides/isolation & purification , Molecular Sequence Data , Phylogeny , Pupa/drug effects , Pupa/growth & development , Sequence Analysis, DNA , Survival Analysis , Trees
9.
Acta Trop ; 111(2): 168-71, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19376077

ABSTRACT

There is no safe and effective drug for killing the adult worms for the elimination/control of lymphatic filariasis and research is very much warranted towards the development of a macrofilaricidal drug. Therefore, the synthesis and evaluation of 1-N-methyl-substituted benzoyl/phenyl acetyl piperazides for macrofilaricidal activity were carried out. The title compounds, 1-N-methyl-substituted benzoyl/phenyl acetyl piperazides were synthesized and purified by slightly modifying the reported procedure and characterized by FT-IR, NMR and mass spectral data. The compounds were screened for macrofilaricidal activity against adult Setaria digitata, the bovine filarial worm for motility and MTT reduction assays using the reported procedures. All the compounds synthesized were characterized by spectral data. Out of 26 compounds synthesized and screened for macrofilaricidal activity, six compounds exhibited moderate antifilarial activity. The structure-activity relationships are discussed. In the case of benzoyl piperazides chloro-substitution in the para position enhanced the activity compared to its substitution in meta and ortho positions. In the case of phenyl acetyl piperazides when methyl group was in the meta position it was more active than when it was in para position. In dimethyl substituted compounds, substitutions at 3, 5-positions were more effective than 2, 3 and 3, 4 substitutions.


Subject(s)
Drug Evaluation, Preclinical , Filaricides/chemical synthesis , Filaricides/pharmacology , Filarioidea/drug effects , Piperazines/chemical synthesis , Piperazines/pharmacology , Animals , Filaricides/chemistry , Humans , Locomotion/drug effects , Magnetic Resonance Spectroscopy , Mass Spectrometry , Microbial Viability/drug effects , Piperazines/chemistry , Spectroscopy, Fourier Transform Infrared , Structure-Activity Relationship , Tetrazolium Salts/metabolism , Thiazoles/metabolism
10.
Acta Trop ; 108(1): 50-3, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18722337

ABSTRACT

Bacillus sphaericus has been widely used in mosquito control programs, but the production of this bacterium is a little tricky as it does not utilize carbohydrates and requires proteinaceous substrates, which are expensive. In this study, we developed a cost-effective medium that resulted in a lower cost and shorter fermentation time. The locally available raw material, egg yolk was used and the level of sporulation, toxicity and biomass were compared with the conventional medium. Use of the egg yolk culture medium significantly shortened fermentation time to 15 h and yielded high activity, equivalent to that of conventional medium against 3rd instar Culex quinquefasciatus. Conventional NYSM medium required 21 h to attain the maximum activity and biomass. Hence, the egg yolk-based culture medium appears to be suitable and economical for the small-scale production of B. sphaericus.


Subject(s)
Bacillus/growth & development , Culture Media/chemistry , Egg Yolk/metabolism , Mosquito Control/methods , Pest Control, Biological/methods , Spores, Bacterial/growth & development , Animals , Bacillus/metabolism , Culex/microbiology , Culture Media/economics , Survival Analysis , Time Factors
11.
Biologicals ; 36(6): 412-5, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18657445

ABSTRACT

Bacillus thuringiensis var. israelensis, a gram positive, spore-forming bacillus, produces parasporal crystal protein during sporulation, which is toxic in the mosquito larvae gut. An efficient downstream processing method for separating the spore crystal complex (SCC) from the fermented broth of B. thuringiensis var. israelensis is required to achieve maximum mosquitocidal activity. The different downstream processing methods, viz., tangential flow ultra-filtration, continuous centrifugation and acid precipitation were compared for their efficiency in separating SCC from broth obtained from a pilot-scale fermentor (100 l capacity). Among the three downstream processing methods, tangential flow ultra-filtration yielded the maximum amount of biomass (53.3g/l), maximum number of spores (2.30 x 10(18)CFU/ml) and highest level of larvicidal activity (LC(50) 28 nl/ml) against Aedes aegypti Bora-Bora strain followed by continuous centrifugation and acid precipitation methods.


Subject(s)
Bacillus thuringiensis/metabolism , Mosquito Control/methods , Pest Control, Biological/methods , Animals , Biological Products/chemistry , Biomass , Biotechnology/methods , Culicidae , Fermentation , Hydrogen-Ion Concentration , Insecticides , Spores, Bacterial
12.
J Ind Microbiol Biotechnol ; 35(9): 961-5, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18509685

ABSTRACT

We reported here the role of amino nitrogen in the commercial production of Bacillus thuringiensis var. israelensis media design. The insect pathogen B. thuringiensis var. israelensis was cultured in different media containing varying initial levels of amino nitrogen sources obtained from three different commercial venders. The biomass, mosquito larval toxicity and spore count produced were measured during the fermentation process. The results showed that the higher level of initial amino nitrogen concentrations in the medium led to higher yield of biomass (dry weight 4.78 g l(-1)), larvicidal activity (LC(50) 18.52 ng ml(-1)) and spore count (3.24 x 10(11) CFU ml(-1)). Similarly decreasing the initial amino nitrogen concentration in the medium led to a decreased biomass (dry weight 1.64 g l(-1)), larvicidal activity (LC(50) 27.01 ng ml(-1)) and spore count (3.7 x 10(10) CFUml(-1)).


Subject(s)
Aedes , Bacillus thuringiensis/drug effects , Bacterial Proteins/biosynthesis , Biomass , Endotoxins/biosynthesis , Hemolysin Proteins/biosynthesis , Insecticides , Mosquito Control , Nitrogen/pharmacology , Aedes/drug effects , Animals , Bacillus thuringiensis/growth & development , Bacillus thuringiensis Toxins , Bacterial Proteins/toxicity , Culture Media , Endotoxins/toxicity , Hemolysin Proteins/toxicity , Larva/drug effects , Lethal Dose 50 , Nitrogen/analysis , Time Factors
13.
Curr Microbiol ; 57(2): 111-4, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18389308

ABSTRACT

Immobilized techniques have been used widely for the controlled release formulation of mosquitoes. Among the microbial formulations, polymeric matrices play an important role in the controlled release of microbial pesticide at rates sufficiently effective to kill mosquitoes in the field. The advantage of these matrices is that they enhance the stability of both spores and toxin against pH, temperature variations, and UV irradiation. The disadvantage of using calcium alginate beads is that they are unstable upon contact with phosphate of potassium or sodium ions rich in the mosquito habitats. To overcome these problems, attempts were made to encapsulate Bacillus thuringiensis var. israelensis within alginate by using different multivalent counterions, namely, calcium chloride, zinc sulfate, copper sulfate, cobalt chloride, and ferric chloride, and the beads formed were tested for its mosquito larvicidal activity. Among all the beads tested, zinc alginate beads resulted in maximum larvicidal activity of 98% (+/-1.40 SE) against Culex quinquefasciatus IIIrd instar larvae and maximum spore count of 3.36 x 10(5) (+/-5291.50 SE) CFU/ml. Zinc alginate beads maintained their structure for up to 48 h when shaken vigorously on a rotary shaker at 180 rpm in the presence of 10 mM potassium phosphate buffer (pH 6.8 +/- 0.1). In conclusion, our results suggest that the use of zinc sulfate as counterions to encapsulate B. thuringiensis var. israelensis within alginate may be a potent mosquito control program in the habitats where more phosphate ions are present.


Subject(s)
Bacillus thuringiensis/chemistry , Insecticides/pharmacology , Mosquito Control/methods , Spores, Bacterial/chemistry , Alginates/metabolism , Animals , Cells, Immobilized , Culicidae/drug effects , Glucuronic Acid/metabolism , Hexuronic Acids/metabolism , Larva/drug effects , Microspheres , Salts/metabolism , Survival Analysis
14.
Acta Trop ; 105(2): 170-5, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18155180

ABSTRACT

Lyophilized cells (sealed and unsealed) and water dispersible powders (WDPs) of two indigenous isolates of Bacillus thuringiensis var.israelensis were stored at -10, 4, 30 and 40 degrees C for up to 4 years and checked for activity. Lyophilized cells stored in sealed condition at -10, 4 and 30 degrees C and WDPs stored at -10 and 4 degrees C were found to maintain the activity fairly well. The lyophilized cells stored at 30 degrees C and WDPs stored at 4 degrees C maintained their larvicidal property for up to 20 years. Hence, lyophilization and WDP formulations are reliable methods for long-term storage of B. t. var. israelensis.


Subject(s)
Bacillus thuringiensis/physiology , Culex , Pest Control, Biological , Preservation, Biological/methods , Animals , Bacillus thuringiensis/growth & development , Culex/growth & development , Freeze Drying , Larva/growth & development , Pest Control, Biological/methods , Powders , Spores, Bacterial
15.
J Microbiol Methods ; 72(1): 91-4, 2008 Jan.
Article in English | MEDLINE | ID: mdl-18054810

ABSTRACT

Technique for immobilization using sodium alginate as the matrix to preserve Bacillus thuringiensis var. israelensis isolates for long time storage was developed. Two strains of B. thuringiensis var. israelensis viz., VCRC B-17 and WHO standard strain IPS-82 were immobilized in alginate matrix and preserved at 4 degrees C and when tested both were found to have maintained excellent viability and mosquito larvicidal activity for 10 years. Mosquito larvicidal activity of B-17 and IPS-82 alginate beads, in term of LC(50) values before storage was 72.07 ng/ml and 47.07 ng/ml, respectively and after storage at 4 degrees C for a period of 1 to 10 years the values ranged from 69.88 to 73.86 ng/ml with a mean of 72.38 ng/ml and 45.32 to 48.60 ng/ml with a mean of 47.49 ng/ml, respectively. Similarly spore count of the beads of the respective strains was 4.37 x 10(8) and 3.33 x 10(10) CFU/mg before storage. After storage at 4 degrees C for a period of 1 to 10 years the counts of the beads of the respective strains ranged from 4.23 x 10(8) to 4.83 x 10(8) CFU/mg (mean of 4.49 x 10(8) CFU/mg) and 3.2 x 10(10) to 3.87 x 10(10) CFU/mg (mean of 3.54 x 10(10) CFU/mg). The alginate matrix immobilization technique has many advantages over free cells are that they enhance the stability of both spores and toxin against several physicochemical conditions and confer reduced susceptibility to contamination.


Subject(s)
Alginates , Bacillus thuringiensis/physiology , Pest Control, Biological , Preservation, Biological/methods , Aedes/growth & development , Animals , Bacteriological Techniques , Cells, Immobilized , Colony Count, Microbial , Freeze Drying , Glucuronic Acid , Hexuronic Acids , Larva/growth & development , Spores, Bacterial/physiology , Time Factors
16.
Acta Trop ; 105(1): 35-8, 2008 Jan.
Article in English | MEDLINE | ID: mdl-17963708

ABSTRACT

Bacillus thuringiensis var. israelensis (B. t. i.) is being widely used in mosquito control programs. However, the large-scale production of this bacillus is expensive due to the high cost of the production medium. In this study, we attempted to develop a cost-effective medium, based on a locally available raw material namely coconut water which is available in plenty as waste product from coconut oil industry. The yield of cell mass, sporulation and mosquito larvicidal activity were studied by growing this bacterium in this waste product and in comparison with the conventional medium (NYSM). Cell mass yield of 3.1g/L, spore count of 3.4x10(11)spores/mL and mosquito larvicidal activity (LC(50)) of 14.85ng/mL (against early fourth-instar larvae of Aedes aegypti) were obtained with a 30h old culture of this bacterium grown in coconut water. This is almost similar to that obtained with NYSM medium. Hence, coconut water-based culture medium is economical for the production of B. t. i.


Subject(s)
Bacillus thuringiensis/growth & development , Bacterial Proteins/metabolism , Bacterial Toxins/metabolism , Bacteriological Techniques , Culture Media/chemistry , Endotoxins/metabolism , Hemolysin Proteins/metabolism , Mosquito Control/methods , Aedes/microbiology , Animals , Bacillus thuringiensis/metabolism , Bacillus thuringiensis/physiology , Bacillus thuringiensis Toxins , Biomass , Cocos/metabolism , Larva/microbiology , Lethal Dose 50 , Spores, Bacterial , Survival Analysis
17.
Biotechnol Bioeng ; 100(1): 103-7, 2008 May 01.
Article in English | MEDLINE | ID: mdl-18023058

ABSTRACT

Reduction of water activity in the formulations of mosquito biocontrol agent, Bacillus thuringiensis var. israelensis is very important for long term and successful storage. A protocol for spray drying of B. thuringiensis var. israelensis was developed through optimizing parameters such as inlet temperature and atomization type. A indigenous isolate of B. thuringiensis var. israelensis (VCRC B-17) was dried by freeze and spray drying methods and the moisture content and mosquito larvicidal activity of materials produced by the two methods were compared. The larvicidal activity was checked against early fourth instars Aedes aegypti larvae. Results showed that the freeze-dried powders retained the larvicidal activity fairly well. The spray-dried powder moderately lost its larvicidal activity at different inlet temperatures. Between the two types of atomization, centrifugal atomization retained more activity than the nozzle type atomization. Optimum inlet temperature for both centrifugal and nozzle atomization was 160 degrees C. Keeping the outlet temperature constant at 70 degrees C the moisture contents for the spray-dried powders through centrifugal atomization and freeze-dried powders were 10.23% and 11.80%, respectively. The LC(50) values for the spray-dried and freeze-dried powders were 17.42 and 16.18 ng/mL, respectively. Spore count of materials before drying was 3 x 10(10) cfu/mL and after spray drying through nozzle and centrifugal atomization at inlet and outlet temperature of 160 degrees C/70 degrees C were 2.6 x 10(9) and 5.0 x 10(9) cfu/mL, respectively.


Subject(s)
Aedes/microbiology , Aerosols/chemistry , Bacillus thuringiensis/physiology , Desiccation/methods , Insecticides , Microfluidics/methods , Pest Control, Biological/methods , Animals
18.
Indian J Med Res ; 126(5): 459-64, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18160751

ABSTRACT

BACKGROUND & OBJECTIVE: Treatment of thromboembolic vascular disease has relied on anticoagulants. However, recognition that lysis of preformed fibrin could be accomplished in vivo by a process involving the conversion of inactive plasminogen to active plasmin enzyme led to an alternative enzyme-based approach. The drugs used for this therapy are called the fibrinolytic enzymes. In this study we attempted the production, purification and characterization of fibrinolytic enzyme from Bacillus sphaericus. METHODS: The seed was prepared in nutrient yeast salt medium (NYSM) in shake flask and organism was produced in 100 l pilot fermentor. Biomass was separated by centrifugation and crude protein was prepared by ammonium sulphate precipitation. Purification was done by ion exchange chromatography using Q sepharose followed by gel filtration chromatography using Sephacryl S- 300. Molecular weight was determined through HPLC. Fibrinolytic activity was assayed by fibrin plate method. RESULTS: The production method yielded 64 mg/l of the crude enzyme and after purification it was 6.3 mg/l. The molecular weight of the compound was 18.6 kDa. INTERPRETATION & CONCLUSION: The enzyme exhibited similar fibrinolytic activity as that of streptokinase, on fibrin plates that were devoid of plasminogen, suggesting that its fibrinolytic action is independent of plasminogen and it is not a plasminogen activator.


Subject(s)
Bacillus/enzymology , Bacterial Proteins , Fibrin/metabolism , Fibrinolytic Agents , Bacterial Proteins/isolation & purification , Bacterial Proteins/metabolism , Bioreactors , Fermentation , Fibrinolytic Agents/isolation & purification , Fibrinolytic Agents/metabolism
19.
Indian J Med Microbiol ; 23(2): 92-4, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15928436

ABSTRACT

PURPOSE: to screen Salmonella typhi in asymptomatic typhoid carriers and to find out drug resistance and ability of the strains to transmit drug resistance to other bacteria. METHODS: Cultural characters, biochemical tests, antibiotic sensitivity test (disc diffusion), agarose gel electrophoresis, and conjugation protocols were done. Thirty five stool samples were collected from the suspected food handlers for the study. RESULTS: Among 35 samples, (17.14%) yielded a positive result. Out of these 4 (20.0%) were women and 2 (13.33%) were men. The isolates were tested with a number of conventional antibiotics viz, amikacin, amoxicillin, ampicillin, chloramphenicol, ciprofloxacin, co-trimaxazole, rifampicin, gentamicin, nalidixic acid, ofloxacin and tetracycline. Five isolates were having the multidrug resistant character. Four (66.66%) multidrug resistant isolates were found to have plasmids, while one (16.66%) multidrug resistant isolate had no plasmid and the chromosome encoded the resistance. Only one strain (16.66%) showed single antibiotic resistance in the study and had no plasmid DNA. The molecular weights of the plasmids were determined and found to be 120 kb. The mechanism of spreading of drug resistance through conjugation process was analyzed. In the conjugation studies, the isolates having R+ factor showed the transfer of drug resistance through conjugation, which was determined by the development of antibiotic resistance in the recipients. CONCLUSION: This study shows that drug resistant strains are able to transfer genes encoding drug resistance.


Subject(s)
Anti-Bacterial Agents/pharmacology , Salmonella typhi/drug effects , Typhoid Fever/microbiology , Adolescent , Adult , Carrier State , Conjugation, Genetic , Drug Resistance, Bacterial/genetics , Drug Resistance, Multiple/genetics , Female , Humans , Male , Middle Aged
20.
Indian J Med Res ; 121(2): 116-9, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15756045

ABSTRACT

BACKGROUND & OBJECTIVES: Biological control through the use of parasitoids and pathogens is one of the alternatives to the use of chemical pesticides for control of insects of public health importance. At the Vector Control Research Centre, a liquid formulation developed using the metabolite of a Pseudomonas fluorescens strain was found to be lethal to larvae as well as pupae of vector mosquitoes. The lethal fraction of the metabolite is a protein with a molecular mass of 44 kDa and toxicity studies showed that it is safe to mammals. In the present study, this formulation was evaluated against immatures of the common house fly, Musca domestica, to find out whether it could be developed into a potential biocontrol tool. METHODS: Early second instar larvae of house fly were introduced into rearing medium incorporated with the formulation at concentrations of 1, 5, 10, 15, 20 and 25 per cent, which were equivalent to respectively 1.13, 5.63, 11.25, 16.88, 22.50 and 28.13 microg of the toxic protein/ g of rearing medium. Mortality was monitored until the emergence of adult house fly. Net mortality of larvae and pupae were calculated and the LC50 and LC90 values were determined through probit regression analysis. RESULTS: Larval mortality was obtained from day 3 to 6 post-treatment. Net mortality of larvae was higher at the concentration of 20 than at 25 per cent. However, it was higher at 25 per cent on day 5 and continued to day 6 when there was no larval mortality at other concentrations. The net mortality of pupae was higher than that of larvae at all the concentrations except at 20 per cent. The LC50 and LC90 values calculated from the net mortality of larvae and pupae together, from day 1 to 12 post-treatment, were respectively, 8.25 and 51.79 microg protein/g of the fly rearing medium. INTERPRETATION & CONCLUSION: The formulation prepared from the exotoxin of P. fluorescens was toxic to the house fly. Pupae were more susceptible than larvae and the activity of the toxin might have been through cuticular absorption. The results are indicative of the possibility of development of the mosquitocidal metabolite for house fly control through appropriate field evaluations.


Subject(s)
Culicidae/microbiology , Diptera/microbiology , Larva/microbiology , Pseudomonas fluorescens/pathogenicity , Animals , Culture Media , Diptera/growth & development
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