bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and partial characterization of ΦSP‐1, a Salmonella specific lytic phage from intestinal content of broiler chicken
Authors: Augustine Jeena , Louis Linda , Varghese Siju M. , Bhat Sarita G. , Kishore Archana 
Published: June 2012

AbstractSalmonella enterica subsp. enterica serovar Enteritidis is a major causative agent of gastroenteritis with contaminated eggs and chicken meat being the major source of infection. Phages are seriously being considered as a safe and cheaper alternative to antibiotics. The intestinal content of chicken was used as source for isolating phages. Phage designated as ΦSP‐1 was selected for the study. Transmission electron microscopy (TEM) of phage ΦSP‐1 revealed that it belonged to family Podoviridae. The optimal multiplicity of infection (MOI) was 5 phages/cell. Latent and rise period were calculated to be 30 and 55 minutes respectively, while burst size was 44 phages/bacterial cell. The genome size of ΦSP‐1 was estimated to be 86 kb from pulsed‐field gel electrophoresis analysis (PFGE). The effect of different physical and chemical parameters like temperature, pH, salinity and CaCl2 were analyzed to optimize the conditions for large scale production of phages and to check the viability of ΦSP‐1 under different physiochemical conditions. A temperature of 40 °C, pH 8 and 0.25 M NaCl were found to be optimum for phage adsorption and it was able to survive up to a temperature of 50 °C for 3 min. Capability to survive under hostile environmental conditions, absence of virulence genes in genome and genus specificity suggest suitability of ΦSP‐1 to be used as a biocontrol agent.
White‐rot fungus Merulius tremellosus KUC9161 identified as an effective degrader of polycyclic aromatic hydrocarbons
Authors: Lee Hwanhwi , Jang Yeongseon , Kim Jong‐Min , Kim Gyu‐Hyeok , Kim Jae‐Jin 
Published: June 2012

AbstractPolycyclic aromatic hydrocarbons (PAHs) have a highly recalcitrant structure; however, they can be degraded by white‐rot fungi which have the potential to biodegrade recalcitrant organic compounds. Four fungal isolates were selected from 23 newly isolated basidiomycetes, based on their dye decolorization rate, and they were evaluated for their ability to degrade 50 ppm of pyrene. The isolate phylogenetically affiliated to Merulius tremellosus KUC9161 demonstrated the highest degradation rate of pyrene, regardless of the production of ligninolytic enzyme activities. The selected isolates were tested for their ability to degrade pyrene and other PAHs in creosote‐contaminated soil. The results of the degradation tests indicated that M. tremellosus KUC9161 degraded a larger variety of PAH compounds than Phanerochaete chrysosporium, a known PAH degrader. On the basis of our results, the isolate M. tremellosus KUC9161 has a high potential to be used in the large‐scale biodegradation of PAHs, and the species may also be used to degrade recalcitrant materials in creosote‐contaminated soil.
Utilization of pyrene and benzoate in Mycobacterium isolate KMS is regulated differentially by catabolic repression
Authors: Zhang Chun , Anderson Anne J. 
Published: June 2012

AbstractThe soil isolate, Mycobacterium sp. strain KMS, utilizes an array of carbon compounds including the aromatics benzoate and pyrene as sole carbon sources. Growth on pyrene induced both chromosomal and plasmid nidA genes encoding pyrene ring‐hydroxylating dioxygenase α‐subunits for pyrene oxidation. Diauxic growth occurred when KMS was cultured with pyrene plus either acetate, succinate, fructose, or benzoate and nidA expression only was detected in the second slower log‐phase period. Potential cAMP‐CRP binding sites exist within the promoter region of both nidA genes indicating that cAMP‐CRP may be involved in catabolite repression of pyrene utilization. When cultured with benzoate plus either acetate, succinate, or fructose, there was no diauxic growth. Also there was no diauxic growth on fructose plus succinate or acetate. Expression of a benA gene, encoding a benzoate dioxygenase α‐subunit involved in the initiation of benzoate oxidation, was detected in log‐phase cells from the benzoate‐mixed substrate cultures at the same level as when the cells were cultured on benzoate alone. These findings suggested that catabolite repression of pyrene but not benzoate occurred in isolate KMS. These differences may help the microbe exploit the varied carbon sources available in the soil and rhizosphere environments.
Occurrence of Metarhizium spp. in Central Brazilian soils
Authors: Rocha Luiz F. N. , Inglis Peter W. , Humber Richard A. , Kipnis André , Luz Christian 
Published: June 2012

AbstractThe biodiversity of entomopathogenic fungi in tropical ecosystems is still little investigated, and the objective of this study was to isolate and identify fungi of the entomopathogenic genus Metarhizium (Hypocreales: Clavicipitaceae) present in undisturbed soils of the Central Brazilian Cerrado. A total of 107 Metarhizium isolates was obtained from soils collected from Cerrado sites in the state of Goiás; gene sequences from 63 of these were obtained and compared. Among these, one was confirmed to be M. anisopliae sensu stricto; 53 were very closely allied to M. anisopliae but require more extensive genetic characterization to determine if they might represent a new taxon in the M. anisopliae species complex. Eight of these Cerrado isolates were referable to M. robertsii, and the remaining isolate is the first South American (and Southern Hemisphere) collection of M. flavoviride var. pemphigi. These findings underline the need for better characterization of the diversity of these widely distributed fungi in Brazil.
Diversity of rhizobia associated with leguminous trees growing in South Korea
Authors: Kang Jun Won , Song Jaekyeong , Doty Sharon L. , Lee Don Koo 
Published: June 2012

AbstractThis study was carried out to examine the diversity of 34 isolates collected from 11 species of leguminous trees growing in South Korea. Phylogenetic relationships between these 34 isolates and reference strains of the Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium and Ensifer/Sinorhizobium were analysed by using 16S rRNA gene sequences. Twenty‐one isolates were related to Mesorhizobium, four isolates to Rhizobium, and nine isolates to Bradyrhizobium. But none of isolates were related to Sinorhizobium/Ensifer and Azorhizobium. Robinia pseudoacacia and Amorpha fruticosa were nodulated by various genotypes of rhizobia out of them, most of the isolates belonged to the genus Mesorhizobium. The isolates from Lespedeza bicolar belonged to diverse genera of Mesorhizobium, Rhizobium, and Bradyrhizobium. The isolates from Maackia amurensis and Lespedeza maximowiezii var. tomentella were phylogenetically related to the genera of Bradyrhizobium. PCR‐based RAPD method and phylogenetic analysis of the 16S rRNA results revealed a high phylogenetic diversity of rhizobial strains nodulating leguminous trees in South Korea. Also, the relationships between host and bacterial phylogenies showed that only Robinia pseudoacacia, and Wisteria floribunda have significantly unique branch length than expected by chance based on phylogenetic tree.
A MAP kinase gene, Clk1, is required for conidiation and pathogenicity in the phytopathogenic fungus Curvularia lunata
Authors: Gao Shi Gang , Zhou Fei Hong , Liu Tong , Li Ying Ying , Chen Jie 
Published: June 2012

AbstractMitogen‐activated protein kinase (MAPK) cascades are highly conserved signal transduction pathways, which play a wide variety of important roles in extracellular signal transduction. The first MAPK gene of the maize pathogen Curvularia lunata, Clk1, was isolated via a PCR‐based approach with a primer pair designed on the basis of conserved regions of known MAPKs. Southern blot analysis showed that the gene existed in the genome as a single copy. The predicted amino acid sequence (352 amino acids) was highly homologous with MAP kinases of other phytopathogenic fungi. Flanking regions of Clk1 were obtained through RACE and genomic walking technology. To understand the role of Clk1 in C. lunata, targeted gene disruption was adopted to construct Clk1 mutants. It was found that mutants lacking functional domain of Clk1 were not able to produce conidia but tended to form a few special chlamydospore‐shaped structures. Clk1 mutants grew slower in adverse environments (at 24°C), produced less cell degrading enzymes (CWDEs) than the wild type, and they were almost unable to infect maize leaves via artificial wounds.
Evaluation of two pretreatment methods for the detection of Mycobacterium tuberculosis in suspected pulmonary tuberculosis
Authors: Shinu Pottathil , Nair Anroop , Jad Beena , Singh Varsha 
Published: June 2012

AbstractThe objective of the current study was to compare the efficacy of phenol ammonium sulphate (PhAS) and sodium hypochlorite (NaOCl) pretreatment methods for the direct microscopy with the Löwenstein‐Jensen (LJ) culture to detect acid fast bacilli (AFB) from pulmonary tuberculosis suspected cases using sputum specimens. To evaluate PhAS and NaOCl methods, sputum specimens (n = 1145) were studied and the performance of each method was compared with LJ media. The, PhAS centrifuged smear and NaOCl centrifuged smear method demonstrated higher sensitivity (71.47% and 77%), specificity (99.61% and 98%), positive predictive value (98.8% and 94.88%) and negative predictive value (88.35% and 90.25%), respectively, when compared to LJ culture. However, the direct AFB smears and PhAS centrifugation method was ineffective to detect few Mycobacterium tuberculosis cases from sputum specimens, particularly in blood tinged specimens with scanty bacilli. Interestingly, NaOCl method could efficiently detect the Mycobacterium tuberculosis cases from blood tinged sputum specimens with scanty bacilli. The current study concluded that NaOCl method could be the most efficient and sensitive method than direct AFB smear and PhAS centrifuged smear method for the direct detection of AFB in suspected cases of pulmonary tuberculosis.
Influence of phosphorus and pH on the fungicidal potential of Anabaena strains
Authors: Chaudhary Vidhi , Prasanna Radha , Bhatnagar Ashok Kumar 
Published: June 2012

AbstractThe genus Anabaena is known to be a rich source of bioactive metabolites, but the biocontrol potential of this genus, mediated through hydrolytic enzymes is less investigated. In our investigation, five Anabaena strains – A. laxa RPAN8, A. iyengarii RPAN9, A. variabilis RPAN59 and A. oscillarioides RPAN69 (with A. variabilis RPAN16 serving as negative control) were evaluated in time course studies involving incubation under three levels of phosphorus and pH conditions. Total chlorophyll, proteins, chitosanase, endoglucanase and CMCase activity were measured and inhibition assayed against phytopathogenic fungi. The four weeks old RPAN69 culture showed significantly higher chlorophyll which was 41% higher than control. This was also linked with an enhancement of 18.26% and 9.18% in chitosanase and CMCase activity respectively over control in the treatment involving half dose of phosphorus. Chlorophyll and CMCase activity showed a high degree of correlation with highest values at pH 9.5. A pH of 5.5 was the most suitable condition for the maximum activity of chitosanase for all the strains except RPAN16. The strains RPAN8 and RPAN9 showed the highest activity of endoglucanase at pH 5.5 while the other strains exhibited maximum activity at pH 7.5. This study provides insight into the role of P and pH in modulating fungicidal activity in different Anabaena strains, which can be valuable for enhancing their efficiency as a biocontrol agent.
An evolutionary analysis of the GH57 amylopullulanases based on the DOMON_glucodextranase_like domains
Authors: Jiao Yu‐Liang , Wang Shu‐Jun , Lv Ming‐Sheng , Fang Yao‐Wei , Liu Shu 
Published: June 2012

AbstractThermostable amylopullulanase (TAPU) is valuable in starch saccharification industry for its capability to catalyze both α‐1,4 and α‐1,6 glucosidic bonds under the industrial starch liquefication condition. The majority of TAPUs belong to glycoside hydrolase family 57 (GH57). In this study, we performed a phylogenetic analysis of GH57 amylopullulanase (APU) based on the highly conserved DOMON_glucodextranase_like (DDL) domain and classified APUs according to their multidomain architectures, phylogenetic analysis and enzymatic characters. This study revealed that amylopullulanase, pullulanase, andα‐amylase had passed through a long joint evolution process, in which DDL played an important role. The phylogenetic analysis of DDL domain showed that the GH57 APU is directly sharing a common ancestor with pullulanase, and the DDL domains in some species undergo evolution scenarios such as domain duplication and recombination.
Isolation and process parameter optimization of Brevibacterium casei for simultaneous bioremediation of hexavalent chromium and pentachlorophenol
Authors: Verma Tuhina , Singh Neha 
Published: June 2012

AbstractChromate and pentachlorophenol are major pollutants discharged through tanneries. Three bacteria resistant to high Cr6+ and PCP concentrations simultaneously were isolated. The TVS‐3 strain was tolerant to highest 850 mg l−1 Cr6+ and 1000 mg l−1 PCP concentration and concomitantly reduced 69% Cr6+ and degraded 72% PCP within 168 h at pH 7.5, 35 ± 1°C temperature, was selected and identified as Brevibacterium casei. At 168 h of growth, bacterium showed maximum PCP utilization of 720 mg l−1 and released 900 mg l−1 chloride ion. The bacterium exhibited remarkable ability to significantly reduce Cr6+ and degrade PCP in presence of other metals, between 100–120 rpm aeration and over broad pH (6.5–10.0) and temperature (30–40°C) range. Maximum 78% Cr6+ reduction and 82% PCP degradation was observed at pH 8.0, 35 ± 1°C within 168 h of incubation, 120 rpm and initial concentration of 850 mg l−1 Cr6+ and 1000 mg l−1 PCP. This is the first study reporting 78% Cr6+ reduction and 82% PCP degradation simultaneously by single native bacteria under wide growth conditions utilizing PCP as sole carbon source. This bacterium may potentially be useful for simultaneous bioremediation of Cr6+ and PCP containing wastes in the environment.
A simple technique for long‐term preservation of leptospires
Authors: Samir Ahmed , Wasfy Momtaz O. 
Published: June 2012

AbstractThe viability of six serovars of Leptospira spp. was studied after long storage at −70°C. The bacteria were either preserved in Ellinghausen–McCullough–Johnson–Harris (EMJH) liquid growth medium or in sheep blood added as a cryoprotectant. The viability of the strains was observed on a monthly basis by dark‐ground microscopy over a period of 20 months at −70°C. Addition of sheep blood was not significantly advantageous, since leptospires that were stored in EMJH showed a slight increase in number after recovery. The results suggest a very simple and useful technique for long‐term preservation of such Leptospira.
Microbial siderophores: a mini review
Authors: Saha Ratul , Saha Nabaneeta , Donofrio Robert S. , Bestervelt Lorelle L. 
Published: June 2012

AbstractIron is one of the major limiting factors and essential nutrients of microbial life. Since in nature it is not readily available in the preferred form, microorganisms produce small high affinity chelating molecules called siderophores for its acquisition. Microorganisms produce a wide variety of siderophores controlled at the molecular level by different genes to accumulate, mobilize and transport iron for metabolism. Siderophores also play a critical role in the expression of virulence and development of biofilms by different microbes. Apart from maintaining microbial life, siderophores can be harnessed for the sustainability of human, animals and plants. With the advent of modern molecular tools, a major breakthrough is taking place in the understanding of the multifaceted role of siderophores in nature. This mini review is intended to provide a general overview on siderophore along with its role and applications.
Influence of cations and anions on the induction of cell density‐independent luminescence in Photorhabdus luminescens
Authors: Tabei Yosuke , Ogawa Akane , Era Mariko , Ninomiya Junko , Morita Hiroshi 
Published: June 2012

AbstractBioluminescence is emitted by various living organisms, including bacteria. While the induction mechanism in marine luminescent bacteria, such as Vibrio fischeri and V. harveyi, has been well characterized, this mechanism has not been studied in detail in the non‐marine luminescent bacterium Photorhabdus luminescens. Therefore, we investigated the effect of cations and anions on the induction of luminescence by P. luminescens. Cultivation of cells in an inorganic salts solution (ISS) containing KCl, CaCl2, MgCl2, NaHCO3, and MgSO4 resulted in a rapid increase in luminescence intensity. Moreover, the induction of luminescence in the ISS medium was not dependent on cell density, since cell densities remained unchanged during 48 h. Furthermore, we found that compounds containing K+, Mg2+, and HCO3– were necessary to induce cell density‐independent luminescence. The intensity of luminescence per cell cultured in medium containing KCl, MgCl2, and NaHCO3 was approximately 100‐fold higher than that cultured in NB. In contrast, when cells actively grew in normal growth condition, the intensity of luminescence per cell was not increased even in the presence of K+, Mg2+, and HCO3–. Thus, these results suggest that the luminescence of P. luminescens is regulated by 2 independent cell density‐dependent and ‐independent mechanisms.
Selenium cannot substitute for sulfur in cell density‐independent bioluminescence in Vibrio fischeri
Authors: Tabei Yosuke , Era Mariko , Ogawa Akane , Ninomiya Junko , Kawano Tomonori , Morita Hiroshi 
Published: June 2012

AbstractIt has been proposed that selenium, an element chemically similar to sulfur, can participate in some of the same biological pathways as sulfur, although only a few studies have been confirmed this. In this study, we investigated the relationship between selenium and sulfur‐dependent luminescence in Vibrio fischeri. The luminescence of V. fischeri was induced by the addition of sulfur‐containing compounds such as Na2SO4 and L‐cystine, and their luminescence was suppressed, in a dose‐dependent manner, by the addition of the selenium‐containing compounds Na2SeO4 and L‐selenocystine. Since the viability of V. fischeri was not affected by the addition of low concentration of selenium‐containing compounds, the decrease in luminescence intensity cannot be explained by cell death. Kinetic analysis performed using Lineweaver‐Burk plots demonstrate that Na2SeO4 and L‐selenocystine act as competitive suppressors in inorganic sulfur (Na2SO4)‐dependent luminescence. In contrast, these selenium‐containing compounds act as uncompetitive suppressors in organic sulfur (L‐cystine)‐dependent luminescence.
Effects of NADH availability on the Klebsiella pneumoniae strain with 1,3‐propanediol operon over‐expression
Authors: Ma Zheng , Shentu Xuping , Bian Yalin , Yu Xiaoping 
Published: June 2012

AbstractIt is generally known that genes dhaB and dhaT are responsible for 1,3‐propanediol (1,3‐PD) production in the presence of glycerol in Klebsiella pneumoniae and these genes are organized in one operon. In the present study, a genetic means of increasing the enzyme activities of 1,3‐PD formation pathway through the over‐expression of 1,3‐PD opeorn was performed in K. pneumoniae S6. The recombinant strain S6‐PD showed 27‐ and 15‐fold increase in enzymatic activities of DhaB and DhaT, respectively with respect to wild‐type strain while failed to improve the 1,3‐PD yield due to the inadequacy of cofactor NADH. Therefore, in order to increase NADH availability, a NADH regeneration system was constructed by heterologous expression of NAD+‐dependent formate dehydrogenase gene (fdh1) from Candida boidinii and introduced into S6‐PD to investigate its effects on the glycerol utilization and 1,3‐PD formation. The results demonstrated that the increase of NADH availability could efficiently improve glycerol metabolism and promote 1,3‐PD yield.
Sodium transport and mechanism(s) of sodium tolerance in Frankia strains
Authors: Srivastava Amrita , Singh Satya Shila , Mishra Arun Kumar 
Published: June 2012

AbstractThe mechanism(s) underlying differential salt sensitivity/tolerance were investigated in the terms of altered morphological and physiological responses against salinity such as growth, electrolyte leakage, Na+ uptake, efflux, accumulation and intracellular concentrations of macronutrients among the Frankia strains newly isolated from Hippöphae salicifolia D. Don. Growth was minimally reduced at 500 and 250 mM NaCl respectively in HsIi10 and rest of the strains (HsIi2, HsIi8, HsIi9) which proved that 500 and 250 mM NaCl are the critical concentrations for the respective strains. The differences in the sodium influx/efflux rate was responsible for the differential amount of remaining sodium among the frankial strains and might be one of the primary determinants for the reestablishment of macronutrients (Mg2+, Ca2+ and K+) during salinity. Secondly, the interactive effect of sodium influx/efflux rate, remaining sodium and intracellular macronutrients (Mg2+, Ca2+ and K+) concentration has been responsible for the extent of membrane damage and growth sustenance of the tolerant/sensitive frankial strains during salinity. HsIi10 showed better co‐regulation of various factors and managed to tolerate salt stress up to considerable extent. Therefore, HsIi10 can serve as a potential biofertilizer in the saline soil.
Optimization of media components for chitinase production by chickpea rhizosphere associated Lysinibacillus fusiformis B‐CM18
Authors: Singh Rajesh Kumar , Kumar D. Praveen , Solanki Manoj Kumar , Singh Pratiksha , Srivastva Alok K. , Kumar Sudheer , Kashyap Prem L. , Saxena Anil K. , Singhal Pradeep K. , Arora Dilip K. 
Published: June 2012

AbstractChitinase producing strain B‐CM18 was isolated from chickpea rhizosphere and identified as Lysinibacillus fusiformis B‐CM18. It showed in vitro antifungal activity against a wide range of fungal plant pathogens and was found to produce several PGPR activities. Further, a multivariate response surface methodology was used to evaluate the effects of different factors on chitinolytic activity and optimizing enzyme production. A central composite design was employed to achieve the highest chitinase production at optimum values of the process variables, viz., temperature (20–45 °C), sodium chloride (2–7%), starch (0.1–1%) and yeast extract (0.1–1%), added in the minimal medium supplemented with colloidal chitin (1–10%; w:w). The fit of the model (R2 = 0.5692) was found to be significant. The production medium to achieve the highest chitinase production (101 U ml−1) was composed of the minimal medium composed of chitin (6.09%), NaCl (4.5%), starch (0.55%) and yeast extract (0.55%) with temperature (32.5 °C). The results show that the optimization strategy led to an increase in chitinase production by 56.1‐fold. The molecular mass of the chitinase was estimated to be 20 kDa by anion exchange and gel filtration chromatography. Further, purified chitinase showed strong antifungal activity against test pathogens. Overall, these results may serve as a base line data for enhancing the chitinolytic potential of bacterial antagonists for bio‐management of chickpea pathogens.