Bidyut R Mohapatra

California Institute of Technology, Pasadena, California, United States

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Publications (25)47.91 Total impact

  • Bidyut R Mohapatra, Myron T La Duc
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    ABSTRACT: Due to their contribution to gastrointestinal and pulmonary disease, their ability to produce various deadly exotoxins, and their resistance to extreme temperature, pressure, radiation, and common chemical disinfecting agents, bacterial endospores of the Firmicutes phylum are a major concern for public and environmental health. In addition, the hardy and dormant nature of endospores renders them a particularly significant threat to the integrity of robotic extraterrestrial life-detection investigations. To prevent the contamination of critical surfaces with seemingly ubiquitous bacterial endospores, clean rooms maintained at exceedingly stringent cleanliness levels (i.e., fewer than 100,000 airborne particles per ft(3)) are used for surgical procedures, pharmaceutical processing and packaging, and fabrication and assembly of medical devices and spacecraft components. However, numerous spore-forming bacterial species have been reported to withstand typical clean room bioreduction strategies (e.g., UV lights, maintained humidity, paucity of available nutrients), which highlights the need for rapid and reliable molecular methods for detecting, enumerating, and monitoring the incidence of viable endospores. Robust means of evaluating and tracking spore burden not only provide much needed information pertaining to endospore ecophysiology in different environmental niches but also empower decontamination and bioreduction strategies aimed at sustaining the reliability and integrity of clean room environments. An overview of recent molecular advances in detecting and enumerating viable endospores, as well as the expanding phylogenetic diversity of pathogenic and clean room-associated spore-forming bacteria, ensues.
    Applied Microbiology and Biotechnology 08/2013; 97(18). DOI:10.1007/s00253-013-5115-3 · 3.81 Impact Factor
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    ABSTRACT: Thiocyanate and cyanide are formed during the processing of gold ores and the production of coke for steel production. Thiocyanate is also formed biologically from the detoxification of cyanide. Thiocyanate is less toxic than cyanide but more stable and thus more difficult to destroy. There are no direct regulatory requirements for the release of thiocyanate into the environment but a number of regulatory agencies have published guidelines for thiocyanate release. Several species of bacteria have been shown to degrade thiocyanate using different biochemical pathways. Some bacteria degrade thiocyanate autotrophically in order to obtain energy and other bacteria utilize thiocyanate as either a sulfur or nitrogen source. Various chemical and biological technologies have been proposed for the destruction of thiocyanate in industrial effluents. Biological systems varying in size from laboratory to full scale have been shown to successfully remove thiocyanate from both industrial and mining effluents. Additional research should be directed towards improving the understanding of the biochemistry of thiocyanate metabolism and scaling up technologies for thiocyanate degradation from laboratory to full scale.
    Minerals Engineering 07/2012; 34:38-47. DOI:10.1016/j.mineng.2012.04.009 · 1.71 Impact Factor
  • Bidyut R Mohapatra, Myron T La Duc
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    ABSTRACT: The survival of Bacillus pumilus SAFR-032 spores to standard industrial clean room sterilization practices necessitates the development of rapid molecular diagnostic tool(s) for detection and enumeration of viable bacterial spores in industrial clean room environments. This is of importance to maintaining the sterility of clean room processing products. This paper describes the effect of propidium monoazide (PMA) on fluorescence in situ hybridization (FISH) for detecting and enumerating B. pumilus SAFR-032 viable spores having been artificially encapsulated within poly(methylmethacrylate) (Lucite, Plexiglas) and released via an organic solvent (PolyGone-500). The results of the PMA-FISH experiments discussed herein indicate that PMA was able to permeate only the compromised coat layers of non-viable spores, identifying PMA treatment of bacterial spores prior to FISH analysis as a novel method for selecting out the fraction of the spore population that is non-viable from fluorescence detection. The ability of novel PMA-FISH to selectively distinguish and enumerate only the living spores present in a sample is of potential significance for development of improved strategies to minimize spore-specific microbial burden in a given environment.
    Journal of microbiological methods 04/2012; 90(1):15-9. DOI:10.1016/j.mimet.2012.04.006 · 2.10 Impact Factor
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    Bidyut R Mohapatra, Myron T La Duc
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    ABSTRACT: Bacillus pumilus SAFR-032 spores originally isolated from the Jet Propulsion Laboratory spacecraft assembly facility clean room are extremely resistant to UV radiation, H(2)O(2), desiccation, chemical disinfection and starvation compared to spores of other Bacillus species. The resistance of B. pumilus SAFR-032 spores to standard industrial clean room sterilization practices is not only a major concern for medical, pharmaceutical and food industries, but also a threat to the extraterrestrial environment during search for life via spacecraft. The objective of the present study was to investigate the potential of Alexa-FISH (fluorescence in situ hybridization with Alexa Fluor® 488 labeled oligonucleotide) method as a molecular diagnostic tool for enumeration of multiple sterilant-resistant B. pumilus SAFR-032 spores artificially encapsulated in, and released via organic solvent from, a model polymeric material: poly(methylmethacrylate) (Lucite, Plexiglas). Plexiglas is used extensively in various aerospace applications and in medical, pharmaceutical and food industries. Alexa-FISH signals were not detected from spores via standard methods for vegetative bacterial cells. Optimization of a spore permeabilization protocol capitalizing on the synergistic action of proteinase-K, lysozyme, mutanolysin and Triton X-100 facilitated efficient spore detection by Alexa-FISH microscopy. Neither of the Alexa-probes tested gave rise to considerable levels of Lucite- or solvent-associated background autofluorescence, demonstrating the immense potential of Alexa-FISH for rapid quantification of encapsulated B. pumilus SAFR-032 spores released from poly(methylmethacrylate).
    Microbiology and Immunology 12/2011; 56(1):40-7. DOI:10.1111/j.1348-0421.2011.00404.x · 1.31 Impact Factor
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    ABSTRACT: The negative impact of acid mine drainage (AMD) on public and environmental health by degrading the aquatic and terrestrial ecosystem with a drastic decrease in pH and elevated levels of toxic heavy metals, metalloids and radionuclides necessitate the development of environmentally sustainable technologies to remediate AMD. The development of appropriate strategies for controlling and/or abating the detrimental effects of AMD in natural and mining environments primarily depends on the diversity and compositions of the local acidophilic microbial communities (those which can grow at pH⩽3) which catalyze the reactions of AMD by production of sulfuric acid and ferric iron. Robust method(s) to track the AMD-promoting microbial communities will not only provide information about their ecophysiological role in extreme environments but also help sustain the reliability of remediation technologies. This paper provides an overview on the phylogenetic diversity of prokaryotes present in AMD-impacted environments, and different molecular methods that have been used to track the diversity of these acidophiles. Additionally, the high-throughput methods (metagenomics, metaproteomics and microarrays) that link prokaryotic phylogeny to their function in AMD systems are also discussed.
    Minerals Engineering 07/2011; 24(8):709-718. DOI:10.1016/j.mineng.2011.03.012 · 1.71 Impact Factor
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    ABSTRACT: Development of environmentally sustainable technologies for remediation of radionuclides is paramount because of their long-term persistence in different ecological niches and acute toxic and teratogenic effects on human, terrestrial and aquatic life. The radionuclides U (VI), Tc (VII), Pu (VI) and Np (V) are enzymatically reduced to environmentally benign U (IV), Tc (IV), Pu (IV) and Np (IV), respectively by anaerobic microorganisms for production of energy and/or as a process of detoxification for their survival. These anaerobic microorganisms produce the oxidoreductase class of enzymes for the metabolism of radionuclides. These microorganisms have potential applications for the in situ environmentally friendly mitigation of radionuclides in subsurface environments. Appropriate knowledge on the biochemical and genetic pathways of radionuclides reduction by microorganisms will not only provide information on the fate and dynamics of these compounds in subsurface geological environments but also help to implement best management practice(s) for immobilization of these toxic compounds in waste effluents generated by the mining and nuclear industries. This review describes the phylogenetic diversity of radionuclides-reducing microorganisms present in the environment, various enzymatic systems associated with the reduction of radionuclides, and identification of genes involved in regulation of different enzymatic redox reactions.
    Minerals Engineering 07/2010; 23(8-23):591-599. DOI:10.1016/j.mineng.2010.03.004 · 1.71 Impact Factor
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    ABSTRACT: Inorganic sulfur compounds are oxidized mostly to sulfate by microorganisms belonging to the bacteria and archaea domains. These microorganisms produce different types of enzymes, e. g., oxidoreductases and hydrolases for the metabolism of inorganic sulfur compounds. These versatile biocatalysts have potential biotechnological applications in different fields including biohydrometallurgical processes for recovering precious heavy metals and also for bioremediation of sulfides in industrial waste effluents. Appropriate knowledge on the enzymatic pathways of inorganic sulfur compounds oxidation will help to tailor the catalytic properties of these microorganisms so that they are optimal not only for a given reaction but also in the context of harsh industrial processes. This review describes the distribution of inorganic sulfur compound-oxidizing microorganisms, various enzymatic systems associated with sulfur metabolism, and identification of the gene(s) responsible for catalysis of different enzymatic reactions.
    CLEAN - Soil Air Water 11/2008; 36(10‐11):823 - 829. DOI:10.1002/clen.200700213 · 1.84 Impact Factor
  • Bidyut R Mohapatra, Klaas Broersma, Asit Mazumder
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    ABSTRACT: Determination of the non-point sources of fecal pollution is essential for the assessment of potential public health risk and development of appropriate management practices for prevention of further contamination. Repetitive extragenic palindromic-PCR coupled with (GTG)(5) primer [(GTG)(5)-PCR] was performed on 573 Escherichia coli isolates obtained from the feces of poultry (chicken, duck and turkey) and free-living (Canada goose, hawk, magpie, seagull and songbird) birds to evaluate the efficacy of (GTG)(5)-PCR genomic fingerprinting in the prediction of the correct source of fecal pollution. A discriminant analysis with the jack-knife algorithm of (GTG)(5)-PCR DNA fingerprints revealed that 95%, 94.1%, 93.2%, 84.6%, 79.7%, 76.7%, 75.3% and 70.7% of magpie, hawk, turkey, seagull, Canada goose, chicken, duck and songbird fecal E. coli isolates classified into the correct host source, respectively. The results of this study indicate that (GTG)(5)-PCR can be considered to be a complementary molecular tool for the rapid determination of E. coli isolates identity and tracking the non-point sources of fecal pollution.
    International journal of medical microbiology: IJMM 05/2008; 298(3-4):245-52. DOI:10.1016/j.ijmm.2007.03.019 · 3.42 Impact Factor
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    ABSTRACT: In order to determine the impact of immobilization on biocatalytic efficacy of sulfide oxidase, the kinetic and thermodynamic properties of native and DEAE-cellulose immobilized sulfide oxidase from Arthrobacter species FR-3 were evaluated. Immobilization increased the catalytic efficiency of sulfide oxidase by producing a lower Michaelis-Menten constant (Km) and a higher rate of catalysis (Vmax) at different temperatures. The first-order kinetic analysis of thermal denaturation demonstrated that the values of enthalpy (delta H*d) and entropy (delta S*d) of immobilized sulfide oxidase were lower than the native enzyme, confirming the thermal stabilization of sulfide oxidase by immobilization. The delta H*d and delta S*d of the immobilized enzyme at 35 degrees C were 138.07 kJ/mol and 122.04 J/K/mol, respectively. These results suggest that immobilization made the sulfide oxidase from Arthrobacter sp. FR-3 thermodynamically more efficient for catalysis of sulfide oxidation.
    Preparative Biochemistry &amp Biotechnology 02/2008; 38(1):61-73. DOI:10.1080/10826060701774361 · 0.70 Impact Factor
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    B R Mohapatra, A Mazumder
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    ABSTRACT: Development of efficient techniques to discriminate the sources of E. coli in aquatic environments is essential to improve the surveillance of fecal pollution indicators, to develop strategies to identify the sources of fecal contamination, and to implement appropriate management practices to minimize gastrointestinal disease transmission. In this study the robustness of five different rep-PCR methods, such as REP-PCR, ERIC-PCR, ERIC2-PCR, BOX-PCR and (GTG)(5)-PCR were evaluated to discriminate 271 E. coli strains isolated from two watersheds (Lakelse Lake and Okanagan Lake) located in British Columbia, Canada. Cluster analysis of (GTG)(5)-PCR, BOX-PCR, REP-PCR, ERIC-PCR and ERIC2-PCR profiles of 271 E. coli revealed 43 clusters, 35 clusters, 28 clusters, 23 clusters and 14 clusters, respectively. The discriminant analysis of rep-PCR genomic fingerprints of 271 E. coli isolates yielded an average rate of correct classification (watershed-specific) of 86.8%, 82.3%, 78.4%, 72.6% and 55.8% for (GTG)(5)-PCR, BOX-PCR, REP-PCR, ERIC-PCR and ERIC2-PCR, respectively. Based on the results of cluster analysis and discriminant function analysis, (GTG)(5)-PCR was found to be the most robust molecular tool for differentiation of E. coli populations in aquatic environments.
    Water Science & Technology 02/2008; 58(3):537-47. DOI:10.2166/wst.2008.424 · 1.21 Impact Factor
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    Bidyut R Mohapatra, Klaas Broersma, Asit Mazumder
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    ABSTRACT: The development of a methodology to identify the origin of fecal pollution is important both for assessing the degree of risk posed to public health and for developing strategies to mitigate the environmental loading of pathogens associated with waterborne disease transmission. Five rep-PCR genomic fingerprinting methods, such as rep-PCR, enterobacterial repetitive intergenic consensus (ERIC)-PCR, ERIC2-PCR, BOX-PCR and (GTG)(5)-PCR, were assessed for their potential in differentiation of 232 fecal Escherichia coli isolates obtained from humans, poultry (chicken, duck and turkey) and wild birds (Canada goose and gull). Based on the results of cluster analysis and discriminant function analysis, (GTG)(5)-PCR was found to be the most suitable method for molecular typing of fecal E. coli, followed by BOX-PCR, REP-PCR, ERIC-PCR and ERIC2-PCR. A discriminant function analysis of (GTG)(5)-PCR fingerprints showed that 94.1%, 79.8%, 80.5%, 74.4%, 86.7% and 88.6% of turkey, chicken, duck, Canada goose, gull and human E. coli isolates were classified into the correct host group, respectively. Subsequently, (GTG)(5)-PCR was tested for its ability to track the origin of 113 environmental E. coli isolated from natural pond water. In conclusion, the (GTG)(5)-PCR genomic fingerprinting method can be considered as a promising genotypic tool for epidemiological surveillance of fecal pollution in aquatic environments.
    FEMS Microbiology Letters 01/2008; 277(1):98-106. DOI:10.1111/j.1574-6968.2007.00948.x · 2.72 Impact Factor
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    B. R. Mohapatra, K. Fukami
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    ABSTRACT: Heterotrophe Nanoflagellaten (HNF) in der Größenordnung von 2 bis 20 μm bilden weitverbreitete einzellige Zooplanktongemeinschaften in aquatischen Lebensräumen. HNF werden als die prinzipiellen Weidegänger auf Bakterien angesehen und spielen eine wesentliche Rolle im Kreislauf organischer Stoffe. Bis heute gibt es wenig Informationen über das chemisch vermittelte artspezifische Fraßverhalten mariner HNF. In dieser Untersuchung wurden die chemosensorischen Reaktionen des vielseitigen marinen HNF Jakoba libera Stamms 5(2) auf die Beutebakterien Pseudomonas sp., Flavobacterium sp. und Aeromonas sp. mit der Kapillarpipettentechnik bei 20 °C im Dunkeln getestet. Die chemosensorische Anziehung war am größten bei dem Beutebakterium Pseudomonas sp., gefolgt von Flavobacterium sp. und Aeromonas sp.. Die chemische Analyse der Komponenten der Bakterienoberfläche von Pseudomonas sp. wiesen darauf hin, dass die chemosensorischen Komponenten ein hohes Molekulargewicht (>25 kiloDalton) und eine Halbwertszeit von 15 min bei 40 °C hatten. Diese Variation in den chemosensorischen Reaktionen von Jakoba libera 5(2) auf verschiedene Beutebakterien stützt die Hypothese, dass HNF chemosensorische Mechanismen nutzen, um ihre Beutebakterien in marinen Umwelten zu finden.
    Basic and Applied Ecology 09/2007; 8(5):475-481. DOI:10.1016/j.baae.2006.08.004 · 2.39 Impact Factor
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    ABSTRACT: Response surface methodology was used to develop a fermentation medium for the enhanced biosynthesis of a novel sulfide oxidase by Arthrobacter species strain FR-3. The interactive effect of the medium components – such as glucose as the carbon source, and tryptone and yeast extract as the nitrogen source – was evaluated by a 23-factorial central composite statistical design. Glucose and yeast extract were found to be the more influential medium constituents compared to tryptone since they had lower coefficients of linear effect, P-values (< 0.02). The optimal fermentation medium components for the enhanced production of sulfide oxidase were recorded as glucose (8.98 g/L), tryptone (10.62 g/L) and yeast extract (7.3 g/L). Optimization of the medium constituents increased the experimental enzyme yield by 54 % compared to the unoptimized medium. This is the first report on the overproduction of sulfide oxidase by using response surface methodology.
    Engineering in Life Sciences 06/2007; 7(3):241 - 246. DOI:10.1002/elsc.200620190 · 1.89 Impact Factor
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    Bidyut R Mohapatra, Klaas Broersma, Rick Nordin, Asit Mazumder
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    ABSTRACT: The objective of this study was to investigate the potential of repetitive extragenic palindromic anchored polymerase chain reaction (rep-PCR) in differentiating fecal Escherichia coli isolates of human, domestic- and wild-animal origin that might be used as a molecular tool to identify the possible source(s) of fecal pollution of source water. A total of 625 fecal E. coli isolates of human, 3 domestic- (cow, dog and horse) and 7 wild-animal (black bear, coyote, elk, marmot, mule deer, raccoon and wolf) species were characterized by rep-PCR DNA fingerprinting technique coupled with BOX A1R primer and discriminant analysis. Discriminant analysis of rep-PCR DNA fingerprints of fecal E. coli isolates from 11 host sources revealed an average rate of correct classification of 79.89%, and 84.6%, 83.8%, 83.3%, 82.5%, 81.6%, 80.8%, 79.8%, 79.3%, 77.4%, 73.2% and 63.6% of elk, human, marmot, mule deer, cow, coyote, raccoon, horse, dog, wolf and black bear fecal E. coli isolates were assigned to the correct host source. These results suggest that rep-PCR DNA fingerprinting procedures can be used as a source tracking tool for detection of human- as well as animal-derived fecal contamination of water.
    Microbiology and Immunology 02/2007; 51(8):733-40. DOI:10.1111/j.1348-0421.2007.tb03962.x · 1.31 Impact Factor
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    B R Mohapatra, N Harris, R Nordin, A Mazumder
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    ABSTRACT: Alcaligenes species CF8 isolated from surface water of a lake produced a novel serine type metallo-caffeine oxidase. The optimal medium for caffeine oxidase production by this strain was (w/v) NaNO(3), 0.4%; KH(2)PO(4), 0.15%; Na(2)HPO(4), 0.05%; FeCl(3).6H(2)O, 0.0005%; CaCl(2).2H(2)O, 0.001%; MgSO(4).7H(2)O, 0.02%; glucose, 0.2%; caffeine, 0.05%, pH 7.5. The enzyme was purified to 63-fold by using ammonium sulfate precipitation, dialysis, ion exchange (diethylaminoethyl-cellulose) and gel filtration (Sephadex G-100) chromatographic techniques. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified caffeine oxidase was monomeric with a molecular mass of 65 kDa. The purified caffeine oxidase with a half-life of 20 min at 50 degrees C had maximal activity at pH 7.5 and 35 degrees C. The purified caffeine oxidase had strict substrate specificity towards caffeine (K(m) 8.94 microM and V(max) 47.62 U mg protein(-1)) and was not able to oxidize xanthine and hypoxanthine. The enzyme activity was not inhibited by para-chloromercuribenzoic acid, iodoacetamide, n-methylmaleimide, salicylic acid and sodium arsenite indicating the enzyme did not belong to xanthine oxidase family. The enzyme was not affected by Ca(+2), Mg(+2) and Na(+), but was completely inhibited by Co(+2), Cu(+2) and Mn(+2) at 1mM level. The novel caffeine oxidase isolated here from Alcaligenes species CF8 may be useful in biotechnological processes including waste treatment and biosensor development.
    Journal of Biotechnology 10/2006; 125(3):319-27. DOI:10.1016/j.jbiotec.2006.03.018 · 2.88 Impact Factor
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    ABSTRACT: Arthrobacter species strain FR-3, isolated from sediments of a swamp, produced a novel serine-type sulfide oxidase. The production of sulfide oxidase was maximal at pH 7.5 and 30 degrees C. Among various carbon and nitrogen sources tested, glucose and yeast extract were found to be the most effective substrates for the secretion of sulfide oxidase. The sulfide oxidase was purified to homogeneity and the molecular weight of the purified enzyme was 43 kDa when estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified sulfide oxidase can be effectively immobilized in DEAE (diethylaminoethyl)-cellulose matrix with a yield of 66%. The purified free and immobilized enzyme had optimum activity at pH 7.5 and 6.0, respectively. Immobilization increases the stability of the enzyme with respect to temperature. The half-life of the immobilized enzyme was 30 min at 45 degrees C, longer than that of the free enzyme (10 min). The purified free sulfide oxidase activity was completely inhibited by 1 mM Co2+ and Zn2+ and sulfhydryl group reagents (para-chloromercuribenzoic acid and iodoacetic acid). Catalytic activity was not affected by 1 mM Ca2+, Mg2+, Na+ and metal-chelating agent (EDTA).
    Journal of Biotechnology 08/2006; 124(3):523-31. DOI:10.1016/j.jbiotec.2006.01.031 · 2.88 Impact Factor
  • B.R. Mohapatra, K. Fukami
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    ABSTRACT: Bacterivorous heterotrophic nanoflagellates (HNF) (2–20 μm in size) are widely distributed protozoan zooplankton communities in aquatic environments. HNF are the major grazers of bacteria and regulate bacterial abundance, and phenotypic and genotypic composition. Consumption of bacteria has profound consequences for plankotonic communities, facilitating the transfer of bacterial biomass to larger consumers that would otherwise be unable to access this food source. Despite the pivotal role of HNF in microbial food web, the species-specific nutritional ecology of HNF is mostly neglected. In this study, the growth kinetics of a marine HNF, Jakoba libera strain 5(2), which was isolated from natural seawater, were compared by feeding with axenic cultures of three marine bacterial strains (Micrococcus sp., Pseudomonas sp. and Vibrio sp.) and mixed communities of marine bacteria. The maximum specific growth rate (μmax), half-saturation constant (KS), HNF yield (Y) and maximum clearance rate (Fmax) of J. libera-5(2) varied with the types of prey bacteria. The μmax, KS, Y and Fmax values of J. libera-5(2) ranged from 0.31–0.79 d−1, 2.0–6.41×106 bacteria ml−1, 4.1–10.61×10−3 flagellate bacteria−1 and 0.97–3.11 nl flagellate−1 h−1, respectively. Among four qualitatively different bacterial strains tested, Pseudomonas species was the most palatable food for J. libera-5(2), followed by Vibrio sp., mixed communities of bacteria and Micrococcus sp. These variations in growth kinetics of J. libera-5(2) on different bacterial strains are supporting evidence for the hypothesis that HNF mediated grazing may be responsible for structuring bacterial species composition in marine environments.ZusammenfassungBakteriovore, heterotrophe Nanoflagellaten (HNF) (der Größe 2–20 μm) sind weit verbreitete protozoische Zooplanktongemeinschaften in aquatischen Lebensräumen. HNF sind die wichtigsten Abweider von Bakterien und regulieren die Bakterienabundanz sowie die phänotypische und genotypische Zusammensetzung. Der Konsum von Bakterien hat grundlegende Konsequenzen für planktonische Gemeinschaften indem der Transfer der bakteriellen Biomasse zu größeren Konsumenten ermöglicht wird, die ansonsten keinen Zugang zu dieser Nahrungsquelle hätten. Trotz der entscheidenden Rolle der HNF im mikrobiellen Nahrungsnetz wurde die artenspezifische Ernährungsökologie der HNF meistens vernachlässigt. In dieser Untersuchung wurden die Wachstumskinetiken eines aus natürlichem Meerwasser isolierten, marinen HNF, Jakoba libera Bakterienstamm 5(2) verglichen, indem er jeweils mit keimfreien Kulturen von drei marinen Bakterienstämmen (Micrococcus sp., Pseudomonas sp. und Vibrio sp.) und gemischen Gemeinschaften von marinen Bakterien gefüttert wurde. Die maximale spezifische Wachstumsrate (μmax), die Halbsättigungskonstante (KS), die HNF-Ausbeute (Y) und die maximale Clearance-Rate (Fmax) von J. libera-5(2) variierte mit den Typen der Beutebakterien. Die μmax-, KS-, Y- und Fmax-Werte von J. libera-5(2) lagen entsprechend zwischen 0.31–0.79 d−1, 2.0–6.41×106 Bakterien ml−1, 4.1–10.61×10−3 Flagellaten Bakterien−1 und 0.97–3.11 nl Flagellaten−1. Unter den vier verschiedenen Bakterienstämmen, die qualitativ getestet wurden, stellten Pseudomonas-Arten die geeignetste Nahrung für J. libera-5(2) dar, gefolgt von Vibrio sp., den gemischten Gemeinschaften von Bakterien und Micrococcus sp.. Diese Variationen in den Wachstumskinetiken von J. libera-5(2) auf verschiedenen Stämmen von Bakterien sind stützende Hinweise für die Hypothese, dass HNF-vermittelte Beweidung für die Strukturierung von bakteriellen Artenzusammensetzungen in marinen Lebensräumen veranwortlich sein kann.
    Basic and Applied Ecology 01/2005; DOI:10.1016/j.baae.2004.08.008 · 2.39 Impact Factor
  • B.R Mohapatra, K Fukami
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    ABSTRACT: The numerical grazing responses of two marine heterotrophic nanoflagellates (HNF), Jakoba libera strain 5(2) and Cafeteria sp. strain 5(3) fed with three bacterial strains (Alteromonas sp., Flavobacterium sp., and Pseudomonas sp.) and mixed bacterial communities (MBC) were compared. J. libera-5(2) had different numerical grazing responses to food bacteria. The net HNF cellular production, maximum specific growth rate (μmax) and maximum clearance rate (Fmax) values of J. libera-5(2) were highest with Pseudomonas sp., followed by Flavobacterium sp., MBC and Alteromonas sp. In contrast, Cafeteria sp.-5(3) showed the same numerical response to the food bacteria, and attained a 57-fold higher net stationary phase population, a 9-fold higher μmax, and a 5-fold higher Fmax than J. libera-5(2) with Alteromonas sp. as food bacteria. These differences in numerical grazing response of HNF may be important in structuring both the bacterial and protozoan species composition and succession in the marine environments.
    Journal of Sea Research 08/2004; DOI:10.1016/j.seares.2004.01.002 · 1.86 Impact Factor
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    B. R. Mohapatra, K. Fukami
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    ABSTRACT: In order to examine the hypothesis that the enzyme levels of heterotrophic nanoflagellates (HNF) are influenced by qualitatively different food bacteria, the production of aminopeptidase by an isolated marine HNF Jakoba libera-5(2) fed on natural communities of bacteria and 6 bacterial strains of 5 different taxonomic groups (Aeromonas, Bacillus, Coryneforms, Flavobacterium and Pseudomonas) were compared. The aminopeptidase activity (total and free) and abundance of J. libera-5(2) significantly differed with the types of food bacteria. The total and free aminopeptidase activities and abundance of J. libera-5(2) were at a maximum with Pseudomonas spp., followed by Flavobacterium sp. and natural communities of bacteria as prey. The values of total aminopeptidase activity of J. libera-5(2) with Pseudomonas spp., Flavobacterium sp. and natural communities of bacteria were 140 +/- 6.78 to 285 +/- 12.36, 123 +/- 11.17 and 38 +/- 0.56 mumol h(-1) l(-1), respectively, and those of free aminopeptidase activity were 83 +/- 6.15 to 137 +/- 5.83, 82 +/- 12.18 and 8 +/- 0.14 mumol h(-1) l(-1), respectively. J. libera-5(2) did not produce any detectable amounts of total and free aminopeptidase while grazing on Aeromonas, Bacillus and Coryneforms. The chemical characterization of partially purified aminopeptidase of J. libera-5(2) produced during grazing on a strain of Pseudomonas sp. indicated the enzyme to be metal-chelater-sensitive alkaline serine aminopeptidase with optimal activity at pH 8.0 and 30degreesC; it was not affected by the major cations of seawater, such as Na(+), Ca(2+) and Mg(2+). The results suggest that at least some marine HNF may significantly contribute to the enzyme pool in marine environments while selectively grazing on bacteria.
    Aquatic Microbial Ecology 02/2004; 34(2). DOI:10.3354/ame034129 · 1.90 Impact Factor
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    B. R. Mohapatra, M. Bapuji, A. Sree
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    ABSTRACT: The abilities of bacteria isolated from eight marine sedentary organisms, six marine sponges (Spirastrella sp., Phyllospongia sp., Ircinia sp., Aaptos sp., Azorica sp. and Axinella sp.), one soft coral (Lobophytum sp.) and one alga (Sargassum sp.) to produce industrial enzymes (amylase, carboxymethylcellulase and protease) were examined. The mean total viable counts of the bacterial isolates ranged from 8.7 × 104 to 8.4 × 105 cfu/g wet weight of the organism. All eight organisms harboured amylase (0.05–0.5 IU/ml), carboxymethylcellulase (0.05–0.5 IU/ml) and protease (0.1–0.5 IU/ml) producing bacteria. Of 56 bacterial strains tested, as many as 60 to 83% of the strains produced at least one of the three enzymes, and 47% of strains were able to produce all three enzymes. High activities (> 0.5 IU/ml) of the three enzymes were recorded in bacterial strains belonging to the genera Alcaligenes and Bacillus. From the results of this study, it appears that bacteria associated with marine sedentary organisms are the novel source of industrial enzymes for possible commercial applications and may play an important role in enzyme-catalysed organic matter cycling in marine environments.
    Acta Biotechnologica 01/2003; 23(1):75 - 84. DOI:10.1002/abio.200390011

Publication Stats

267 Citations
47.91 Total Impact Points


  • 2011–2013
    • California Institute of Technology
      Pasadena, California, United States
  • 2012
    • University of South Alabama
      Mobile, Alabama, United States
  • 2007–2011
    • Natural Resources Canada
      Ottawa, Ontario, Canada
  • 2006–2008
    • University of Victoria
      • Department of Biology
      Victoria, British Columbia, Canada
  • 2004–2007
    • Kochi University
      • Faculty of Agriculture
      Kôti, Kōchi, Japan
  • 1997
    • Council of Scientific and Industrial Research (CSIR), New Delhi
      New Dilli, NCT, India