Pyridine degradation characteristics of Rhodococcus sp. LV4 under high salinity conditions / 生物工程学报

Biodegradation of pyridine pollutant by microorganisms is one of the economical and effective methods to solve the environmental pollution of pyridine under high salinity conditions. To this end, screening of microorganisms with pyridine degradation capability and high salinity tolerance is an important prerequisite. In this paper, a salt-resistant pyridine degradation bacterium was isolated from the activated sludge of Shanxi coking wastewater treatment plant, and identified as a bacterium belonging to Rhodococcus on the basis of colony morphology and 16S rDNA gene phylogenetic analysis. Salt tolerance experiment showed that strain LV4 could grow and degrade pyridine with the initial concentration of 500 mg/L completely in 0%-6% saline environment. However, when the salinity was higher than 4%, strain LV4 grew slowly and the degradation time of pyridine by strain LV4 was significantly prolonged. Scanning electron microscopy showed that the cell division of strain LV4 became slower, and more granular extracellular polymeric substance (EPS) was induced to secrete in high salinity environment. When the salinity was not higher than 4%, strain LV4 responded to the high salinity environment mainly through increasing the protein content in EPS. The optimum conditions for pyridine degradation by strain LV4 at 4% salinity were 30 ℃, pH 7.0 and 120 r/min (DO 10.30 mg/L). Under these optimal conditions, strain LV4 could completely degrade pyridine with an initial concentration of 500 mg/L at a maximum rate of (29.10±0.18) mg/(L·h) after 12 h adaptation period, and the total organic carbon (TOC) removal efficiency reached 88.36%, indicating that stain LV4 has a good mineralization effect on pyridine. By analyzing the intermediate products in pyridine degradation process, it was speculated that strain LV4 achieved pyridine ring opening and degradation mainly through two metabolic pathways: pyridine-ring hydroxylation and pyridine-ring hydrogenation. The rapid degradation of pyridine by strain LV4 in high salinity environment indicates its application potential in the pollution control of high salinity pyridine environment.

Efficacy and safety of Nocardia rubra cell wall skeleton for the treatment of erosive oral lichen planus / 北京大学学报(医学版)

OBJECTIVE@#To observe the efficacy and safety of Nocardia rubra cell wall skeleton (Nr-CWS) for the treatment of erosive oral lichen planus (EOLP).@*METHODS@#Sixty patients with clinically and pathologically diagnosed EOLP were randomly divided into the experimental group and control group according to the random number. Patients in the experimental group were treated with lyophilized powder containing Nr-CWS combined with normal saline. Patients in the control group received topical placebo without Nr-CWS combined with normal saline. Changes in the EOLP lesion area and the patient's pain level were recorded at the timepoints of weeks 1, 2, and 4 after the two different treatments, respectively. The changes of the patient's REU scoring system (reticulation, erythema, ulceration), the visual analogue scale and the oral health impact score (OHIP-14) were compared between the experimental group and control group after treatment, and the safety indicators of the two groups at the initial diagnosis and after 4 weeks' treatment were also observed, respectively.@*RESULTS@#Totally, 62 patients with clinically and pathologically diagnosed EOLP were enrolled, 2 of whom were lost to the follow-up, with 31 in the experimental group, and 29 in the control group. The mean age of the experimental group and control group were (52.9±12.4) years and (54.07±12.40) years, respectively. There was no significant difference in the oral periodontal index between the experimental group and control group. In the experimental group, the erosive area of oral lichen planus was significantly reduced 1, 2, and 4 weeks after the Nr-CWS's treatment (P < 0.05), the reduction rate was 81.75%, the patient's pain index was also decreased (P < 0.05), and in addition, the OHIP-14 was reduced (P < 0.05). The changes of the REU scoring system, the visual analogue scale and the OHIP-14 were significantly different between the experimental group and control group after treatment. There was no significant difference in the safety index between the two groups.@*CONCLUSION@#The priliminary data show that the Nr-CWS is effective and safe to treat EOLP.

Isolation, identification and characterization of a chloramphenicol-degrading bacterium / 生物工程学报

Microorganisms are the dominant players driving the degradation and transformation of chloramphenicol (CAP) in the environment. However, little bacterial strains are able to efficiently degrade and mineralize CAP, and the CAP degrading pathways mediated by oxidative reactions remain unclear. In this study, a highly efficient CAP-degrading microbial consortium, which mainly consists of Rhodococcus (relative abundance >70%), was obtained through an enrichment process using CAP-contaminated activated sludge as the inoculum. A bacterial strain CAP-2 capable of efficiently degrading CAP was isolated from the consortium and identified as Rhodococcus sp. by 16S rRNA gene analysis. Strain CAP-2 can efficiently degrade CAP under different nutrient conditions. Based on the biotransformation characteristics of the detected metabolite p-nitrobenzoic acid and the reported metabolites p-nitrobenzaldehyde and protocatechuate by strain CAP-2, a new oxidative pathway for the degradation of CAP was proposed. The side chain of CAP was oxidized and broken to generate p-nitrobenzaldehyde, which was further oxidized to p-nitrobenzoic acid. Strain CAP-2 can be used to further study the molecular mechanism of CAP catabolism, and has the potential to be used in in situ bioremediation of CAP-contaminated environment.

Optimisation of biodegradation conditions for waste canola oil by cold-adapted Rhodococcus sp. AQ5-07 from Antarctica

BACKGROUND: The potential waste canola oil-degrading ability of the cold-adapted Antarctic bacterial strain Rhodococcus sp. AQ5-07 was evaluated. Globally, increasing waste from food industries generates serious anthropogenic environmental risks that can threaten terrestrial and aquatic organisms and communities. The removal of oils such as canola oil from the environment and wastewater using biological approaches is desirable as the thermal process of oil degradation is expensive and ineffective. RESULTS: Rhodococcus sp. AQ5-07 was found to have high canola oil-degrading ability. Physico-cultural conditions influencing its activity were studied using one-factor-at-a-time (OFAT) and statistical optimisation approaches. Considerable degradation (78.60%) of 3% oil was achieved by this bacterium when incubated with 1.0 g/L ammonium sulphate, 0.3 g/L yeast extract, pH 7.5 and 10% inoculum at 10°C over a 72-h incubation period. Optimisation of the medium conditions using response surface methodology (RSM) resulted in a 9.01% increase in oil degradation (87.61%) when supplemented with 3.5% canola oil, 1.05 g/L ammonium sulphate, 0.28g/L yeast extract, pH 7.5 and 10% inoculum at 12.5°C over the same incubation period. The bacterium was able to tolerate an oil concentration of up to 4.0%, after which decreased bacterial growth and oil degradation were observed. CONCLUSIONS: These features make this strain worthy of examination for practical bioremediation of lipid-rich contaminated sites. This is the first report of any waste catering oil degradation by bacteria originating from Antarctica.

Peritoneal Dialysis Catheter-Related Infection due to Mycobacterium abscessus Confused with Rhodococcus

No abstract available.

Pathologic characteristics for the Rhodococcus equi infection in foals in Jeju / 대한수의학회지

From 1996 to 2014, 14 foals from nine farms in Jeju were diagnosed with a Rhodococcus equi infection. Clinically, most foals showed characteristic respiratory signs, including hyperthermia and dyspnea. The seasonal occurrence of R. equi infection in foals was higher in summer, such as June (eight foals; 57.1%) and July (four foals; 28.6%), than in the other seasons. The major cases of R. equi infections were observed among two-month-old (eight foals; 57.1%) and three-month-old (three foals; 21.4%) foals. Histopathologically, bronchopneumonia, abscess, and granulomatous pneumonia were the most prevalent lesions in the lungs of foals. Colonic ulcers and submucosal abscesses were found in a foal. Some foals showed granulomatous lymphadenitis and abscesses in the mesenteric and other lymph nodes. According to the polymerase chain reaction using 10 tissue samples of foals and nine R. equi isolates, the vapA gene was detected in 11/11 (100%) foals. Immunohistochemical staining using the anti-VapA monoclonal antibody was applied to detect the R. equi VapA antigen in the organs of foals. R. equi VapA antigens were demonstrated in most lungs and some mesenteric and hilar lymph nodes of 13 foals. Isolated virulent R. equi VapA bacteria showed high sensitivity to gentamicin, quinolones, rifampin, and vancomycin.

Characterization of Rhodococcus sp. A5wh isolated from a high altitude Andean lake to unravel the survival strategy under lithium stress / Caracterización de las estrategias seguidas por Rhodococcus sp. A5wh proveniente de laguna de altura en su adaptación a la presencia de litio

Lithium (Li) is widely distributed in nature and has several industrial applications. The largest reserves of Li (over 85%) are in the so-called "triangle of lithium" that includes the Salar de Atacama in Chile, Salar de Uyuni in Bolivia and Salar del Hombre Muerto in Argentina. Recently, the use of microorganisms in metal recovery such as copper has increased; however, there is little information about the recovery of lithium. The strain Rhodococcus sp. A5wh used in this work was previously isolated from Laguna Azul. The assays revealed that this strain was able to accumulate Li (39.52% of Li/g microbial cells in 180 min) and that it was able to grow in its presence up to 1 M. In order to understand the mechanisms implicated in Li tolerance, a proteomic approach was conducted. Comparative proteomic analyses of strain A5wh exposed and unexposed to Li reveal that 17 spots were differentially expressed. The identification of proteins was performed by MALDI-TOF/MS, and the obtained results showed that proteins involved in stress response, transcription, translations, and metabolism were expressed under Li stress. This knowledge constitutes the first proteomic approach to elucidate the strategy followed by Rhodococcus to adapt to Li.

El litio (Li) es un elemento químico con múltiples aplicaciones industriales. Es considerado uno de los minerales más ampliamente distribuidos en la naturaleza. Sus mayores reservas (más del 85%) se encuentran en el llamado «triángulo de litio¼: salar de Atacama, en Chile; salar de Uyuni, en Bolivia, y salar del Hombre Muerto, en Argentina. En los últimos años, el empleo de microorganismos en la recuperación de metales se ha visto incrementado; sin embargo, hay muy poca información sobre la recuperación de Li por esta vía. En este estudio se trabajó con Rhodococcus sp. A5wh, cepa aislada de Laguna Azul. Los ensayos revelaron que este microorganismo fue capaz de acumular Li (39,52% de Li/g de biomasa en 180 min) y de crecer en presencia de este metaloide hasta una concentración de 1 M. Para comprender los mecanismos implicados en la tolerancia al Li, se llevó a cabo el análisis proteómico comparativo de esta cepa expuesta o no expuesta al Li. Los resultados revelaron 17 spots expresados en forma diferencial. La identificación de las proteínas se realizó porMALDI-TOF/MS. Este estudio constituye el primer enfoque proteómico para dilucidar la estrategia seguida por Rhodococcus en su adaptación al estrés.

Rubber gloves biodegradation by a consortium, mixed culture and pure culture isolated from soil samples

Abstract An increasing production of natural rubber (NR) products has led to major challenges in waste management. In this study, the degradation of rubber latex gloves in a mineral salt medium (MSM) using a bacterial consortium, a mixed culture of the selected bacteria and a pure culture were studied. The highest 18% weight loss of the rubber gloves were detected after incubated with the mixed culture. The increased viable cell counts over incubation time indicated that cells used rubber gloves as sole carbon source leading to the degradation of the polymer. The growth behavior of NR-degrading bacteria on the latex gloves surface was investigated using the scanning electron microscope (SEM). The occurrence of the aldehyde groups in the degradation products was observed by Fourier Transform Infrared Spectroscopy analysis. Rhodococcus pyridinivorans strain F5 gave the highest weight loss of rubber gloves among the isolated strain and posses latex clearing protein encoded by lcp gene. The mixed culture of the selected strains showed the potential in degrading rubber within 30 days and is considered to be used efficiently for rubber product degradation. This is the first report to demonstrate a strong ability to degrade rubber by Rhodococcus pyridinivorans.

A medium supplemented with vegetable extract used for cellulose production of Rhodococcus SP. MI 2 / Meio suplementado com extrato vegetal utilizado na produção de celulose de Rhodococcus SP. MI 2

In this study, the most suitable vegetable extract was screened to use as non-conventional nutrient sources for cellulose production of Rhodococcus sp. MI 2. SH medium or a synthetic medium was used as a conventional or control medium. Cha-poo (Piper sarmentosum Roxb.) and sweet potato (Ipomoea batatas Lam.) were 2 out of 14 vegetable extracts chosen as medium supplements. Rhodococcus sp. MI 2 gave the highest cellulose yield in a medium supplemented with Cha-poo extract. The optimum culture conditions in the medium supplemented with Cha-poo extract at room temperature (25o C) under static condition were 5% (v v-1) inoculum size, a 6 -day -incubation period, pH 3, 3% sucrose, and 0.5% (NH4)2SO4. The cellulose yield in the medium supplemented with Cha-poo extract was increased about 3 times (6.83 g L-1 during 6 days) higher than that obtained before optimizing (2.39 g L-1 during 6 days). The medium supplemented with Cha-poo extract cost one quarter (0.5 USD L-1 of medium) of the SH medium (1.9 USD L-1 of medium). The structure of the microfibrils of cellulose produced by Rhodococcus sp. MI 2 in a medium supplemented with Cha-poo extract observed by SEM had larger, less crowded fibrils than those produced in the medium supplemented with sweet potato extract. In addition, the microfibrils of the former had many beehive shaped knots whereas those of the latter had mantle-like surrounding the fibrils.

Neste estudo, o extrato vegetal mais adequado foi triado para uso como fontes não convencionais de nutrientes para produção de celulose de Rhodococcus sp. MI 2. Utilizou-se um meio SH ou meio sintético como meio convencional ou de controle. Cha-poo (Piper sarmentosum Roxb.) e batata-doce (Ipomoea batatas Lam.) foram 2 dos 14 extratos vegetais escolhidos como suplementos do meio. Rhodococcus sp. MI 2 deu o maior rendimento de celulose em um meio suplementado com extrato de Cha-poo. As condições ótimas de cultivo no meio suplementado com extrato de Cha-poo em temperatura ambiente (25 ºC) em condição estática foram 5% (v v-1) do tamanho do inóculo, um período de 6 dias de incubação, pH 3, 3% de sacarose, e 0,5% (NH4) 2SO4. O rendimento de celulose no meio suplementado com extrato de Cha-poo foi aumentado cerca de 3 vezes (6,83 g L-1 durante 6 dias), maior do que o obtido antes da otimização (2,39 g L-1 durante 6 dias). O meio suplementado com extrato de Cha-poo custou um quarto (0,5 USD L-1 de meio) do meio SH (1,9 USD L-1 de meio). A estrutura das microfibrilas de celulose produzidas por Rhodococcus sp. MI 2 em meio suplementado com extrato de Cha-poo, observado por MEV, apresentou fibrilas maiores e menos congestionadas do que aquelas produzidas no meio suplementado com extrato de batata-doce. Além disso, as microfibrilas do primeiro possuíam muitos nós em forma de colmeia, enquanto os do último tinham um aspecto tipo manto ao redor das fibras.

Cutaneous Microflora from Geographically Isolated Groups of Bradysia agrestis, an Insect Vector of Diverse Plant Pathogens

Larvae of Bradysia agrestis, an insect vector that transports plant pathogens, were sampled from geographically isolated regions in Korea to identify their cutaneous fungal and bacterial flora. Sampled areas were chosen within the distribution range of B. agrestis; each site was more than 91 km apart to ensure geographical segregation. We isolated 76 microbial (fungi and bacteria) strains (site 1, 29; site 2, 29; site 3, 18 strains) that were identified on the basis of morphological differences. Species identification was molecularly confirmed by determination of universal fungal internal transcribed spacer and bacterial 16S rRNA gene sequences in comparison to sequences in the EzTaxon database and the NCBI GenBank database, and their phylogenetic relationships were determined. The fungal isolates belonged to 2 phyla, 5 classes, and 7 genera; bacterial species belonged to 23 genera and 32 species. Microbial diversity differed significantly among the geographical groups with respect to Margalef's richness (3.9, 3.6, and 4.5), Menhinick's index (2.65, 2.46, and 3.30), Simpson's index (0.06, 0.12, and 0.01), and Shannon's index (2.50, 2.17, and 2.58). Although the microbial genera distribution or diversity values clearly varied among geographical groups, common genera were identified in all groups, including the fungal genus Cladosporium, and the bacterial genera Bacillus and Rhodococcus. According to classic principles of co-evolutionary relationship, these genera might have a closer association with their host insect vector B. agrestis than other genera identified. Some cutaneous bacterial genera (e.g., Pseudomonas) displaying weak interdependency with insect vectors may be hazardous to agricultural environments via mechanical transmission via B. agrestis. This study provides comprehensive information regarding the cutaneous microflora of B. agrestis, which can help in the control of such pests for crop management.

Partial purification and characterization of the recombinant benzaldehyde dehydrogenase from rhodococcus ruber UKMP-5M

Background: Benzaldehyde dehydrogenase [BZDH] is encoded by the xylC that catalyzes the conversion of benzaldehyde into benzoate in many pathways such as toluene degradation

Objectives: In this study, the xylC gene from Rhodococcus ruber UKMP-5M was expressed in Escherichia coli, purified, and characterized

Materials and Methods: The xylC was amplified and cloned in E. coli. The recombinant plasmid pGEMT-xylC was digested by NdeI and HindIII to construct plasmid pET28b-xylC and transformed in E. coli BL21 [DE3]. Expression of the recombinant protein was induced by 1 mM isopropyl beta-D-thiogalactoside [IPTG] at 37[degree]C. The BZDH was purified by ion exchange chromatography, in which the product was an NAD-dependent enzyme using benzaldehyde as a substrate for enzyme characterization. The end metabolite was identified via gas chromatography mass spectrometry [GC-MS]

Results: The recombinant BZDH is 27 kDa, purified by ion exchange chromatography. The activity of BZDH was 9.4 U.microL[-1] The optimum pH and temperature were 8.5 and 25[degree]C, respectively. The Michaelis constant [K[m]] and maximum velocity [V[max]] were 4.2 mM and 19.7 U.mL[-1], respectively. The metabolite of BZDH was benzene carboxylic acid as determined by GC-MS analysis

Conclusions: BZDH has the ability to degrade benzaldehyde to less toxic compounds. The BZDH is a critical enzyme for the degradation of aromatic hydrocarbons in Rhodococcus sp. The BZDH from R. ruber UKMP-5M is showed similar function with other aldehyde dehydrogenases

Response of Rhodococcus erythropolis strain IBBPo1 to toxic organic solvents

Abstract Recently, there has been a lot of interest in the utilization of rhodococci in the bioremediation of petroleum contaminated environments. This study investigates the response of Rhodococcus erythropolis IBBPo1 cells to 1% organic solvents (alkanes, aromatics). A combination of microbiology, biochemical, and molecular approaches were used to examine cell adaptation mechanisms likely to be pursued by this strain after 1% organic solvent exposure. R. erythropolis IBBPo1 was found to utilize 1% alkanes (cyclohexane, n-hexane, n-decane) and aromatics (toluene, styrene, ethylbenzene) as the sole carbon source. Modifications in cell viability, cell morphology, membrane permeability, lipid profile, carotenoid pigments profile and 16S rRNA gene were revealed in R. erythropolis IBBPo1 cells grown 1 and 24 h on minimal medium in the presence of 1% alkanes (cyclohexane, n-hexane, n-decane) and aromatics (toluene, styrene, ethylbenzene). Due to its environmental origin and its metabolic potential, R. erythropolis IBBPo1 is an excellent candidate for the bioremediation of soils contaminated with crude oils and other toxic compounds. Moreover, the carotenoid pigments produced by this nonpathogenic Gram-positive bacterium have a variety of other potential applications.

Isolation of an aryloxyphenoxy propanoate (AOPP) herbicide-degrading strain Rhodococcus ruber JPL-2 and the cloning of a novel carboxylesterase gene (feh)

The strain JPL-2, capable of degrading fenoxaprop-P-ethyl (FE), was isolated from the soil of a wheat field and identified as Rhodococcus ruber. This strain could utilize FE as its sole carbon source and degrade 94.6% of 100 mg L−1 FE in 54 h. Strain JPL-2 could also degrade other aryloxyphenoxy propanoate (AOPP) herbicides. The initial step of the degradation pathway is to hydrolyze the carboxylic acid ester bond. A novel esterase gene feh, encoding the FE-hydrolyzing carboxylesterase (FeH) responsible for this initial step, was cloned from strain JPL-2. Its molecular mass was approximately 39 kDa, and the catalytic efficiency of FeH followed the order of FE > quizalofop-P-ethyl > clodinafop-propargyl > cyhalofop-butyl > fluazifop-P-butyl > haloxyfop-P-methyl > diclofop-methy, which indicated that the chain length of the alcohol moiety strongly affected the hydrolysis activity of the FeH toward AOPP herbicides.

Biodegradation of crude oil by individual bacterial strains and a mixed bacterial consortium

Three bacterial isolates identified as Alcanivorax borkumensis SK2, Rhodococcus erythropolis HS4 and Pseudomonas stutzeri SDM, based on 16S rRNA gene sequences, were isolated from crude oil enrichments of natural seawater. Single strains and four bacterial consortia designed by mixing the single bacterial cultures respectively in the following ratios: (Alcanivorax: Pseudomonas, 1:1), (Alcanivorax: Rhodococcus, 1:1), (Pseudomonas: Rhodococcus, 1:1), and (Alcanivorax: Pseudomonas: Rhodococcus, 1:1:1), were analyzed in order to evaluate their oil degrading capability. All experiments were carried out in microcosms systems containing seawater (with and without addition of inorganic nutrients) and crude oil (unique carbon source). Measures of total and live bacterial abundance, Card-FISH and quali-, quantitative analysis of hydrocarbons (GC-FID) were carried out in order to elucidate the co-operative action of mixed microbial populations in the process of biodegradation of crude oil. All data obtained confirmed the fundamental role of bacteria belonging to Alcanivorax genus in the degradation of linear hydrocarbons in oil polluted environments.

A Case of Recurrent Meningitis Caused by Rhodococcus species Successfully Treated with Antibiotic Treatment and Intrathecal Injection of Vancomycin through an Ommaya Reservoir / 감염과화학요법

Human infection by Rhodococcus species is rare and mostly limited to immunocompromised hosts such as patients infected with the human immunodeficiency virus (HIV) or organ transplant recipients. The most common strain is R. equi, and the most common clinical presentation is pulmonary infection, reported in 80% of Rhodococcus spp. infections. The central nervous system is an uncommon infection site. We report a case of a patient with pneumonia, brain abscess, and recurrent meningitis caused by Rhodococcus spp. He initially presented with pneumonia with necrosis, which progressed to brain abscess and recurrent meningitis. Rhodococcus spp. was identified from the cerobrospinal fluid (CSF) collected during his fourth hospital admission. Despite prolonged treatment with appropriate antibiotics, meningitis recurred three times. Finally, in order to administer antibiotics directly into the CSF and bypass the blood-brain barrier, an Ommaya reservoir was inserted for administration of 90 days of intrathecal vancomycin and amikacin in conjunction with intravenous and oral antibiotics; the patient was finally cured with this treatment regimen.

Variación diurna en la composición del bacterioplancton y daño del ADN en la comunidad microbiana de un lago oligotrófico andino / Diurnal variation in bacterioplankton composition and DNA damage in the microbial community from an Andean oligotrophic lake

Laguna Azul is an oligotrophic lake situated at 4,560 m above sea level and subject to a high level of solar radiation. Bacterioplankton community composition (BCC) was analysed by denaturing gradient gel electrophoresis and the impact of solar ultraviolet radiation was assessed by measuring cyclobutane pyrimidine dimers (CPD). Furthermore, pure cultures of Acinetobacter johnsonii A2 and Rhodococcus sp. A5 were exposed simultaneously and CPD accumulation was studied. Gel analyses generated a total of 7 sequences belonging to Alpha-proteobacteria (1 band), Beta-proteobacteria (1 band), Bacteroidetes (2 bands), Actinobacteria (1 band), and Firmicutes (1 band). DGGE profiles showed minimal changes in BCC and no CPD was detected even though a high level of damage was found in biodosimeters. A. johnsonii A2 showed low level of DNA damage while Rhodococcus sp. A5 exhibited high resistance since no CPD were detected under natural UV-B exposure, suggesting that the bacterial community is well adapted to this highly solar irradiated environment.

La Laguna Azul es un ambiente oligotrófico localizado a 4560m de altura y sometido a elevados niveles de radiación solar. La composición de su comunidad bacterioplanctónica fue analizada empleando la técnica de electroforesis en gradiente desnaturalizante y se investigó el impacto de la radiación ultravioleta cuantificando los dímeros de pirimidina (CPD). Además, se expusieron simultáneamente cultivos puros de Acinetobacter johnsonii A2 y Rhodococcus sp. A5 para estudiar la acumulación de CPD. El análisis de los geles mostró siete secuencias pertenecientes a Alpha-proteobacteria (1 banda), Beta-proteobacteria (1 banda), Bacteroidetes (2 bandas), Actinobacteria (1 banda) y Firmicutes (1 banda). A lo largo del día se observaron cambios mínimos en la composición de la comunidad y no se detectaron CPD. A. johnsonii A2 presentó un daño bajo mientras que Rhodococcus sp. A5 no presentó daño en su ADN, sugiriendo que la comunidad bacteriana está muy bien adaptada a este ambiente altamente irradiado

Optimization of Culture Conditions for Enhanced Antimicrobial Activity of Rhodococcus erythropolis VLK-12 Isolated from South Coast of Andhra Pradesh, India.

Aims: To Isolate and characterize the antimicrobial actinomycetes from the marine habitats of south coast of Andhra Pradesh, India. Place and Duration of the Study: Marine habitats of south coast of Andhra Pradesh, India, between June 2011 and July 2012. Methodology: The soil samples were collected, pre-treated and plated on yeast extractmalt extract dextrose agar medium. Identification of the strain was carried out by employing the polyphasic taxonomical studies including the 16S rRNA sequence based analysis. Phylogenetic tree was constructed using the Molecular Evolutionary Genetic Analysis (MEGA) version 5. The influence of culture conditions and the effect of environmental factors on the biomass and antimicrobial activy\ity of the strain was the focus of this study. Results: A total of 20 actinobacteria were isolated from the marine habitats of south coast of Andhra Pradesh, India, and screened for antimicrobial activity against test bacteria and fungi. The potent bioactive metabolite producing strain was designated as VLK-12. Further polyphasic studies revealed that the Isolate VLK-12 belongs to the genera Rhodococcus. Phylogenetic analysis of 16S rRNA sequencing studies revealed that the strain is closely related to Rhodococcus erythropolis. The crude ethyl acetate extract obtained by culturing the strain on YMD inhibited Gram positive and Gram negative bacteria along with fungi. Conclusion: Rhodococcus erythropolis isolated from the marine habitats of south coast of Andhra Pradesh exhibited antimicrobial activity against pathogens.

Sternal Osteomyelitis Caused by Gordonia bronchialis after Open-Heart Surgery / 감염과화학요법

We report the case of a deep sternal wound infection with sternal osteomyelitis caused by Gordonia bronchialis after open-heart surgery. The isolate was identified as a G. bronchialis by 16S rRNA and hsp65 gene sequencing, having initially been misidentified as a Rhodococcus by a commercial phenotypic identification system.

Biosurfactant production by Rhodococcus erythropolis and its application to oil removal

The influence of different nutrients on biosurfactant production by Rhodococcus erythropolis was investigated. Increasing the concentration of phosphate buffer from 30 up through 150 mmol/L stimulated an increase in biosurfactant production, which reached a maximum concentration of 285 mg/L in shaken flasks. Statistical analysis showed that glycerol, NaNO3,MgSO4 and yeast extract had significant effects on production. The results were confirmed in a batchwise bioreactor, and semi-growth-associated production was detected. Reduction in the surface tension, which indicates the presence of biosurfactant, reached a value of 38 mN/m at the end of 35 hours. Use of the produced biosurfactant for washing crude oil-contaminated soil showed that 2 and 4 times the critical micellar concentration (CMC) were able to remove 97 and 99 percent of the oil, respectively, after 1 month of impregnation.

A Case Report of Tsukamurella pulmonis Infection Misidentified as Atypical Mycobacteria / 대한임상미생물학회지

We report a case of catheter-related bacteremia due to Tsukamurella pulmonis. T. pulmonis is a rare cause of opportunistic infection in immunosuppressed patients and in cases of indwelling foreign materials. This infection was nearly impossible to identify using conventional phenotyping methods because of its similarities to the related genera Nocardia, Rhodococcus, Gordonia, Streptomyces, Corynebacterium, and Mycobacterium. This organism was initially misidentified as Mycobacterium aubagnense through PCR-RFLP analysis. We correctly identified this organism using 16S rRNA sequencing combined with phenotyping tests.