B-cell chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal B cells ... more B-cell chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal B cells that are resistant to apoptosis as a result of bcl2 oncogene overexpression. Studies were done to determine the mechanism for the up-regulation of bcl-2 protein observed in CD19+ CLL cells compared with CD19+ B cells from healthy volunteers. The 11-fold higher level of bcl-2 protein in CLL cells was positively correlated with a 26-fold elevation in the cytosolic level of nucleolin, a bcl2 mRNA–stabilizing protein. Measurements of the bcl2 heterogeneous nuclear/bcl2 mRNA (hnRNA)/mRNA ratios and the rates of bcl2 mRNA decay in cell extracts indicated that the 3-fold higher steady-state level of bcl2 mRNA in CLL cells was the result of increased bcl2 mRNA stability. Nucleolin was present throughout the nucleus and cytoplasm of CLL cells, whereas in normal B cells nucleolin was only detected in the nucleus. The addition of recombinant human nucleolin to extracts of normal B cells markedly sl...
The 3′-UTR (untranslated region) of bcl-2 mRNA contains an ARE (AU-rich element) that potentially... more The 3′-UTR (untranslated region) of bcl-2 mRNA contains an ARE (AU-rich element) that potentially regulates the stability of bcl-2 mRNA in a cell specific fashion. Previous studies have demonstrated that multiple proteins interact with bcl-2 mRNA in HL-60 (human leukaemia-60) cells, potentially contributing to the overexpression of Bcl-2 protein. Treatment of HL-60 cells with taxol or okadaic acid has been shown to induce destabilization of bcl-2 mRNA, which was associated with decreased binding of trans-acting factors to bcl-2 mRNA. Nucleolin has been identified as one of the bcl-2 mRNA-binding proteins [Sengupta, Bandyopadhyay, Fernandes and Spicer (2004) J. Biol. Chem. 279, 10855–10863]. In an effort to identify additional bcl-2 mRNA-binding proteins, two polypeptides of approx. 45 kDa and 60 kDa were isolated from HL-60 cells by AREbcl-2 (transcripts that contain bcl-2 AREs) RNA affinity chromatography. These proteins were identified as the human proliferation associated protein...
OSM (oncostatin M) is a pleiotropic cytokine belonging to the IL (interleukin) 6 family that modu... more OSM (oncostatin M) is a pleiotropic cytokine belonging to the IL (interleukin) 6 family that modulates the growth of some cancer cell lines. We have found that PMA treatment of human U937 lymphoma cells increased the steady-state levels of OSM mRNA. Furthermore, the half-life of OSM mRNA was increased from 2.3 to 6.2 h. Measurement of mRNA/hnRNA (heterogeneous nuclear RNA) ratios in PMA-treated cells suggests further that the increase in OSM mRNA is due to enhanced mRNA stability. Consistent with this, synthetic OSM mRNA transcripts decayed faster in extracts of untreated U937 cells than in extracts of PMA-treated cells. The 3′-untranslated region of OSM mRNA contains a putative ARE (AU-rich element) that may play a role in mRNA stabilization. Addition of the OSM ARE motif to the 3′-end of β-globin mRNA increased its decay rate in vitro. Decay assays with β-globin–AREOSM and β-globin transcripts indicate that PMA induces mRNA stabilization in an ARE-dependent manner. PMA also induce...
Pseudomonas aeruginosa is a medically important bacteria due to its ability to form biofilm and i... more Pseudomonas aeruginosa is a medically important bacteria due to its ability to form biofilm and is also an opportunistic pathogen. Pseudomonas aeruginosa has the intrinsic ability to form biofilm as one of the defense mechanisms for their survival. The fact that it can form biofilms on various medical implants makes it more harmful clinically. Although various antibiotics are used to treat Pseudomonas aeruginosa infections, previous studies have shown that sub-MIC levels of antibiotics cause biofilm formation in this type of bacteria. The present study thus deals with the effect of the aminoglycoside antibiotic gentamicin on the biofilm dynamics of two Pseudomonas aeruginosa strains KPW.1-S1 and HRW.1-S3. Biofilm formation was seen to be increasing with increased gentamicin concentrations in growth media. Confocal laser scanning microscopy and scanning electron microscopy accompanied with other biochemical tests deduced that biofilm-forming components like exoproteins, eDNA, and exo...
The objective of the present study was to characterize aresenate reductase of pH, salt and arsena... more The objective of the present study was to characterize aresenate reductase of pH, salt and arsenate tolerant Bacillus thuringiensis KPWP1, isolated from contaminated surface water. Interestingly, it was found that the arsC, arsB and arsR genes involved in arsenate tolerance are distributed in the genome of KPWP1. The inducible arsC gene was cloned, expressed and the purified ArsC protein showed profound enzyme activity with the KM and Kcat values as 25 µM and 0.00119 s− 1, respectively. In silico studies of KPWP1 ArsC revealed that in spite of 19–26% differences in gene sequences, the ArsC proteins of Bacillus thuringiensis, Bacillus subtilis and Bacillus cereus are structurally conserved and KPWP1 ArsC structure is close to nature. Docking and analysis of binding site showed that arsenate ion interacts with three cysteine residues of ArsC of KPWP1and predicts that the ArsC from B. thuringiensis reduces arsenate by using the triple Cys redox relay mechanism.
Applied microbiology and biotechnology, Jan 9, 2015
Pseudomonas sp. has long been known for production of a wide range of secondary metabolites durin... more Pseudomonas sp. has long been known for production of a wide range of secondary metabolites during late exponential and stationary phases of growth. Phenazine derivatives constitute a large group of secondary metabolites produced by microorganisms including Pseudomonas sp. Phenazine 1,6-di-carboxylic acid (PDC) is one of such metabolites and has been debated for its origin from Pseudomonas sp. The present study describes purification and characterization of PDC isolated from culture of a natural isolate of Pseudomonas sp. HRW.1-S3 while grown in presence of crude oil as sole carbon source. The isolated PDC was tested for its effect on biofilm formation by another environmental isolate of Pseudomonas sp. DSW.1-S4 which lacks the ability to produce any phenazine compound. PDC showed profound effect on both planktonic as well as biofilm mode of growth of DSW.1-S4 at concentrations between 5 and 20 μM. Interestingly, PDC showed substantial cytotoxicity against three cancer cell lines an...
The bioavailability of organic contaminants to the degrading bacteria is a major limitation to ef... more The bioavailability of organic contaminants to the degrading bacteria is a major limitation to efficient bioremediation of sites contaminated with hydrophobic pollutants. Such limitation of bioavailability can be overcome by steady-state biofilm-based reactor. The aim of this study was to examine the effect of such multicellular aggregation by naturally existing oil-degrading bacteria on crude oil degradation. Microorganisms, capable of utilizing crude oil as sole carbon source, were isolated from river, estuary and sea-water samples. Biochemical and 16S rDNA analysis of the best degraders of the three sources was found to belong to the Pseudomonas species. Interestingly, one of the isolates was found to be close to Pseudomonas otitidis family which is not reported yet as a degrader of crude oil. Biodegradation of crude oil was estimated by gas chromatography, and biofilm formation near oil-water interface was quantified by confocal laser scanning microscopy. Biofilm supported batch...
Multiresolution analysis on the spatial refractive index inhomogeneities in the epithelium and co... more Multiresolution analysis on the spatial refractive index inhomogeneities in the epithelium and connective tissue regions of a human cervix reveals a clear signature of multifractality. Importantly, the derived multifractal parameters, namely, the generalized Hurst exponent and the width of the singularity spectrum, derived via multifractal detrended fluctuation analysis, shows interesting differences between tissues having different grades of precancers. The refractive-index fluctuations are found to be more anticorrelated, and the strength of multifractality is observed to be considerably stronger in the higher grades of precancers. These observations on the multifractal nature of tissue refractive-index variations may prove to be valuable for developing light-scattering approaches for noninvasive diagnosis of precancer and early-stage cancer.
Background Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecti... more Background Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecting children. Despite significant progress and success in the treatment of ALL, a significant number of children continue to relapse and for them, outcome remains poor. Therefore, the search for novel therapeutic approaches is warranted. The aim of this study was to investigate the AMP activated protein kinase (AMPK) as a potential target in childhood acute lymphoblastic leukemia (ALL) subtypes characterized by non-random translocation signature profiles. We evaluated the effects of the AMPK activator AICAR on cell growth, cell cycle regulators and apoptosis of various childhood ALL cells. Results We found that treatment with AICAR inhibited cell proliferation, induced cell cycle arrest in G1-phase, and apoptosis in CCRF-CEM (T-ALL), NALM6 (Bp-ALL), REH (Bp-ALL, TEL/AML1) and SupB15 (Bp-ALL, BCR/ABL) cells. These effects were abolished by treatment with the adenosine kinase inhibitor 5...
The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size a... more The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size are reported. A dose dependent degradation of isolated DNA molecules by copper nanoparticles through generation of singlet oxygen was observed. Singlet oxygen scavengers such as sodium azide and Tris [hydroxyl methyl] amino methane were able to prevent the DNA degradation action of copper nanoparticles confirming the involvement of activated oxygen species in the degradation process. Additionally, it was observed that the copper nanoparticles are able to exert cytotoxic effect towards U937 and Hela cells of human histiocytic lymphoma and human cervical cancer origins, respectively by inducing apoptosis. The growth characteristics of U937 and Hela cells were studied applying various concentrations of the copper nanoparticles.
Breast cancer is considered as a leading cause of cancer-related death worldwide. The development... more Breast cancer is considered as a leading cause of cancer-related death worldwide. The development of chemotherapeutic resistance and the production of undesirable side effects steer the search for new potential candidates with therapeutic implications.Lantana camarahas been reported to cure a number of ailments, with few studies showing its cytotoxic effect on breast cancer cell lines. However, the impact ofLantana camaraon triple negative breast cancer cells is largely obscure to date. The present study investigated the effect of ethanolic extract ofLantana camaraleaves on the triple negative breast cancer cell line, MDA-MB-231. We found thatLantana camaraleaf extract induced cytomorphological changes and exhibited a growth inhibitory effect on MDA-MB-231 cells in a dose-dependent manner. The extract was observed to induce G0/G1 cell cycle arrest. Nuclear staining of the cells exposed toLantana camaraleaf extract suggested the presence of condensed nuclei and the result of flow cyt...
B-cell chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal B cells ... more B-cell chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal B cells that are resistant to apoptosis as a result of bcl2 oncogene overexpression. Studies were done to determine the mechanism for the up-regulation of bcl-2 protein observed in CD19+ CLL cells compared with CD19+ B cells from healthy volunteers. The 11-fold higher level of bcl-2 protein in CLL cells was positively correlated with a 26-fold elevation in the cytosolic level of nucleolin, a bcl2 mRNA–stabilizing protein. Measurements of the bcl2 heterogeneous nuclear/bcl2 mRNA (hnRNA)/mRNA ratios and the rates of bcl2 mRNA decay in cell extracts indicated that the 3-fold higher steady-state level of bcl2 mRNA in CLL cells was the result of increased bcl2 mRNA stability. Nucleolin was present throughout the nucleus and cytoplasm of CLL cells, whereas in normal B cells nucleolin was only detected in the nucleus. The addition of recombinant human nucleolin to extracts of normal B cells markedly sl...
The 3′-UTR (untranslated region) of bcl-2 mRNA contains an ARE (AU-rich element) that potentially... more The 3′-UTR (untranslated region) of bcl-2 mRNA contains an ARE (AU-rich element) that potentially regulates the stability of bcl-2 mRNA in a cell specific fashion. Previous studies have demonstrated that multiple proteins interact with bcl-2 mRNA in HL-60 (human leukaemia-60) cells, potentially contributing to the overexpression of Bcl-2 protein. Treatment of HL-60 cells with taxol or okadaic acid has been shown to induce destabilization of bcl-2 mRNA, which was associated with decreased binding of trans-acting factors to bcl-2 mRNA. Nucleolin has been identified as one of the bcl-2 mRNA-binding proteins [Sengupta, Bandyopadhyay, Fernandes and Spicer (2004) J. Biol. Chem. 279, 10855–10863]. In an effort to identify additional bcl-2 mRNA-binding proteins, two polypeptides of approx. 45 kDa and 60 kDa were isolated from HL-60 cells by AREbcl-2 (transcripts that contain bcl-2 AREs) RNA affinity chromatography. These proteins were identified as the human proliferation associated protein...
OSM (oncostatin M) is a pleiotropic cytokine belonging to the IL (interleukin) 6 family that modu... more OSM (oncostatin M) is a pleiotropic cytokine belonging to the IL (interleukin) 6 family that modulates the growth of some cancer cell lines. We have found that PMA treatment of human U937 lymphoma cells increased the steady-state levels of OSM mRNA. Furthermore, the half-life of OSM mRNA was increased from 2.3 to 6.2 h. Measurement of mRNA/hnRNA (heterogeneous nuclear RNA) ratios in PMA-treated cells suggests further that the increase in OSM mRNA is due to enhanced mRNA stability. Consistent with this, synthetic OSM mRNA transcripts decayed faster in extracts of untreated U937 cells than in extracts of PMA-treated cells. The 3′-untranslated region of OSM mRNA contains a putative ARE (AU-rich element) that may play a role in mRNA stabilization. Addition of the OSM ARE motif to the 3′-end of β-globin mRNA increased its decay rate in vitro. Decay assays with β-globin–AREOSM and β-globin transcripts indicate that PMA induces mRNA stabilization in an ARE-dependent manner. PMA also induce...
Pseudomonas aeruginosa is a medically important bacteria due to its ability to form biofilm and i... more Pseudomonas aeruginosa is a medically important bacteria due to its ability to form biofilm and is also an opportunistic pathogen. Pseudomonas aeruginosa has the intrinsic ability to form biofilm as one of the defense mechanisms for their survival. The fact that it can form biofilms on various medical implants makes it more harmful clinically. Although various antibiotics are used to treat Pseudomonas aeruginosa infections, previous studies have shown that sub-MIC levels of antibiotics cause biofilm formation in this type of bacteria. The present study thus deals with the effect of the aminoglycoside antibiotic gentamicin on the biofilm dynamics of two Pseudomonas aeruginosa strains KPW.1-S1 and HRW.1-S3. Biofilm formation was seen to be increasing with increased gentamicin concentrations in growth media. Confocal laser scanning microscopy and scanning electron microscopy accompanied with other biochemical tests deduced that biofilm-forming components like exoproteins, eDNA, and exo...
The objective of the present study was to characterize aresenate reductase of pH, salt and arsena... more The objective of the present study was to characterize aresenate reductase of pH, salt and arsenate tolerant Bacillus thuringiensis KPWP1, isolated from contaminated surface water. Interestingly, it was found that the arsC, arsB and arsR genes involved in arsenate tolerance are distributed in the genome of KPWP1. The inducible arsC gene was cloned, expressed and the purified ArsC protein showed profound enzyme activity with the KM and Kcat values as 25 µM and 0.00119 s− 1, respectively. In silico studies of KPWP1 ArsC revealed that in spite of 19–26% differences in gene sequences, the ArsC proteins of Bacillus thuringiensis, Bacillus subtilis and Bacillus cereus are structurally conserved and KPWP1 ArsC structure is close to nature. Docking and analysis of binding site showed that arsenate ion interacts with three cysteine residues of ArsC of KPWP1and predicts that the ArsC from B. thuringiensis reduces arsenate by using the triple Cys redox relay mechanism.
Applied microbiology and biotechnology, Jan 9, 2015
Pseudomonas sp. has long been known for production of a wide range of secondary metabolites durin... more Pseudomonas sp. has long been known for production of a wide range of secondary metabolites during late exponential and stationary phases of growth. Phenazine derivatives constitute a large group of secondary metabolites produced by microorganisms including Pseudomonas sp. Phenazine 1,6-di-carboxylic acid (PDC) is one of such metabolites and has been debated for its origin from Pseudomonas sp. The present study describes purification and characterization of PDC isolated from culture of a natural isolate of Pseudomonas sp. HRW.1-S3 while grown in presence of crude oil as sole carbon source. The isolated PDC was tested for its effect on biofilm formation by another environmental isolate of Pseudomonas sp. DSW.1-S4 which lacks the ability to produce any phenazine compound. PDC showed profound effect on both planktonic as well as biofilm mode of growth of DSW.1-S4 at concentrations between 5 and 20 μM. Interestingly, PDC showed substantial cytotoxicity against three cancer cell lines an...
The bioavailability of organic contaminants to the degrading bacteria is a major limitation to ef... more The bioavailability of organic contaminants to the degrading bacteria is a major limitation to efficient bioremediation of sites contaminated with hydrophobic pollutants. Such limitation of bioavailability can be overcome by steady-state biofilm-based reactor. The aim of this study was to examine the effect of such multicellular aggregation by naturally existing oil-degrading bacteria on crude oil degradation. Microorganisms, capable of utilizing crude oil as sole carbon source, were isolated from river, estuary and sea-water samples. Biochemical and 16S rDNA analysis of the best degraders of the three sources was found to belong to the Pseudomonas species. Interestingly, one of the isolates was found to be close to Pseudomonas otitidis family which is not reported yet as a degrader of crude oil. Biodegradation of crude oil was estimated by gas chromatography, and biofilm formation near oil-water interface was quantified by confocal laser scanning microscopy. Biofilm supported batch...
Multiresolution analysis on the spatial refractive index inhomogeneities in the epithelium and co... more Multiresolution analysis on the spatial refractive index inhomogeneities in the epithelium and connective tissue regions of a human cervix reveals a clear signature of multifractality. Importantly, the derived multifractal parameters, namely, the generalized Hurst exponent and the width of the singularity spectrum, derived via multifractal detrended fluctuation analysis, shows interesting differences between tissues having different grades of precancers. The refractive-index fluctuations are found to be more anticorrelated, and the strength of multifractality is observed to be considerably stronger in the higher grades of precancers. These observations on the multifractal nature of tissue refractive-index variations may prove to be valuable for developing light-scattering approaches for noninvasive diagnosis of precancer and early-stage cancer.
Background Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecti... more Background Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecting children. Despite significant progress and success in the treatment of ALL, a significant number of children continue to relapse and for them, outcome remains poor. Therefore, the search for novel therapeutic approaches is warranted. The aim of this study was to investigate the AMP activated protein kinase (AMPK) as a potential target in childhood acute lymphoblastic leukemia (ALL) subtypes characterized by non-random translocation signature profiles. We evaluated the effects of the AMPK activator AICAR on cell growth, cell cycle regulators and apoptosis of various childhood ALL cells. Results We found that treatment with AICAR inhibited cell proliferation, induced cell cycle arrest in G1-phase, and apoptosis in CCRF-CEM (T-ALL), NALM6 (Bp-ALL), REH (Bp-ALL, TEL/AML1) and SupB15 (Bp-ALL, BCR/ABL) cells. These effects were abolished by treatment with the adenosine kinase inhibitor 5...
The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size a... more The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size are reported. A dose dependent degradation of isolated DNA molecules by copper nanoparticles through generation of singlet oxygen was observed. Singlet oxygen scavengers such as sodium azide and Tris [hydroxyl methyl] amino methane were able to prevent the DNA degradation action of copper nanoparticles confirming the involvement of activated oxygen species in the degradation process. Additionally, it was observed that the copper nanoparticles are able to exert cytotoxic effect towards U937 and Hela cells of human histiocytic lymphoma and human cervical cancer origins, respectively by inducing apoptosis. The growth characteristics of U937 and Hela cells were studied applying various concentrations of the copper nanoparticles.
Breast cancer is considered as a leading cause of cancer-related death worldwide. The development... more Breast cancer is considered as a leading cause of cancer-related death worldwide. The development of chemotherapeutic resistance and the production of undesirable side effects steer the search for new potential candidates with therapeutic implications.Lantana camarahas been reported to cure a number of ailments, with few studies showing its cytotoxic effect on breast cancer cell lines. However, the impact ofLantana camaraon triple negative breast cancer cells is largely obscure to date. The present study investigated the effect of ethanolic extract ofLantana camaraleaves on the triple negative breast cancer cell line, MDA-MB-231. We found thatLantana camaraleaf extract induced cytomorphological changes and exhibited a growth inhibitory effect on MDA-MB-231 cells in a dose-dependent manner. The extract was observed to induce G0/G1 cell cycle arrest. Nuclear staining of the cells exposed toLantana camaraleaf extract suggested the presence of condensed nuclei and the result of flow cyt...
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