Polyurethane (PUR) plastics is widely used because of its unique physical and chemical properties. However, unreasonable disposal of the vast amount of used PUR plastics has caused serious environmental pollution. The efficient degradation and utilization of used PUR plastics by means of microorganisms has become one of the current research hotspots, and efficient PUR degrading microbes are the key to the biological treatment of PUR plastics. In this study, an Impranil DLN-degrading bacteria G-11 was isolated from used PUR plastic samples collected from landfill, and its PUR-degrading characteristics were studied. Strain G-11 was identified as Amycolatopsis sp. through 16S rRNA gene sequence alignment. PUR degradation experiment showed that the weight loss rate of the commercial PUR plastics upon treatment of strain G-11 was 4.67%. Scanning electron microscope (SEM) showed that the surface structure of G-11-treated PUR plastics was destroyed with an eroded morphology. Contact angle and thermogravimetry analysis (TGA) showed that the hydrophilicity of PUR plastics increased along with decreased thermal stability upon treatment by strain G-11, which were consistent with the weight loss and morphological observation. These results indicated that strain G-11 isolated from landfill has potential application in biodegradation of waste PUR plastics.
Plastics/metabolism* ; Polyurethanes/chemistry* ; RNA, Ribosomal, 16S ; Bacteria/genetics* ; Biodegradation, Environmental

BACKGROUNDAccurate identification of bacterial isolates is an essential task in clinical microbiology. This study compared culturing to analyzing 16S rRNA gene sequences as methods to identify bacteria in clinical samples. We developed a key technique to directly identify bacteria in clinical samples via nucleic acid sequences, thus improving the ability to confirm pathogens.

METHODSWe obtained 225 samples from Beijing Tongren Hospital and examined them by conventional culture and 16S rDNA sequencing to identify pathogens. This study made use of a modified sample pre-treatment technique which came from our laboratory to extract DNA. 16S rDNA was amplified by PCR. The amplified product was sequenced on a CEQ8000 capillary sequencer. Sequences were uploaded to the GenBank BLAST database for comparison.

RESULTSAmong the positively cultivated bacterial strains, seven strains were identified differently by Vitek32 and by 16S rDNA sequencing. Twelve samples that were negative by standard culturing were determined to have pathogens by sequence analysis.

CONCLUSIONThe use of 16S rRNA gene sequencing can improve clinical microbiology by providing better identification of unidentified bacteria or providing reference identification of unusual strains.

Bacteria ; isolation & purification ; DNA, Ribosomal ; chemistry ; Humans ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S ; genetics ; Sequence Analysis, DNA ; methods

Marine Actinobacteria are emerging as new resources for bioactive natural products with promise in novel drug discovery. In recent years, the richness and diversity of marine Actinobacteria from the South China Sea and their ability in producing bioactive products have been investigated. The objective of this work is to isolate and identify bioactive secondary metabolites from a marine actinobacterium SCSIO 1934 derived from sediments of South China Sea. The strain was identified as a Streptomyces spieces by analyzing its 16S rDNA sequence. Streptomyces sp. SCSIO 1934 was fermented under optimized conditions and seven bioactive secondary metabolites were isolated and purified by chromatographic methods including colum chromatography over silica gel and Sephadex LH-20. Their structures were elucidated as 17-O-demethylgeldanamycin (1), lebstatin (2), 17-O-demethyllebstatin (3), nigericin (4), nigericin sodium salt (5), abierixin (6), respectively, by detailed NMR spectroscopic data (1H, 13C, COSY, HSQC and HMBC). This work provided a new marine actinobacterium Streptomyces sp. SCSIO 1934, capable of producing diverse bioactive natural products.
Anti-Bacterial Agents ; chemistry ; China ; DNA, Ribosomal ; chemistry ; genetics ; Geologic Sediments ; microbiology ; Oceans and Seas ; RNA, Ribosomal, 16S ; genetics ; Streptomyces ; chemistry ; classification ; genetics ; isolation & purification

OBJECTIVETo establish the specific 16S-23S rRNA gene spacer regions in different bacteria using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), DNA cloning and sequences analysis.

METHODSA pair of primers were selected from highly conserved sequences adjacent to the 16S-23S rRNA spacer region. Bacterial DNA from sixty-one strains of standard bacteria and corresponding clinical isolates representative of 20 genera and 26 species was amplified by PCR, and further analyzed by RFLP, DNA cloning and sequences analysis. Furthermore, all specimens were examined by bacterial culturing and PCR-RFLP analysis. The evaluation of these assays in practical clinic practice was also discussed.

RESULTSRestriction enzyme analysis revealed one, two or three bands or more observed among the 26 different standard strains. The sensitivity of PCR reached 2.5 colony-forming unit (CFU), and there was no cross reaction with human genomic DNA, fungus or virus. Fourteen species could be distinguished immediately by PCR, while another 10 species were further identified by Hinf I or Alu I digestion. The only difference between K.pneumoniae and E. durans was located at the site of the 779th nucleotide according to the sequence analysis and only XmaIII digestion could distinguish one from another. Of 42 specimens from septicemic neonates, 15 were identified as positive by blood culture at a rate of 35.7%. However, 27 specimens identified as positive by PCR, with a rate of 64.2%, a method significantly more effective than blood culture (P < 0.01). Of 6 cerebrospinal fluid (CSF) specimens, one tested positive for S.epidermidis was also positive by PCR, two culture negative were positive by PCR and diagnosed as S.epidermidis according to the DNA pattern. One positive for C.neoformans was negative by PCR. The other two specimens were negative by both PCR and culture.

CONCLUSIONSThe method of detecting bacterial 16S-23S rRNA spacer regions using PCR-RFLP techniques was specific, sensitive, rapid and accurate in providing a new technique for detecting pathogens in clinical bacterial infections.

Bacteria ; genetics ; isolation & purification ; DNA, Bacterial ; analysis ; chemistry ; DNA, Ribosomal ; analysis ; chemistry ; Genes, rRNA ; Humans ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; RNA, Ribosomal, 16S ; genetics ; RNA, Ribosomal, 23S ; genetics ; Sensitivity and Specificity ; Sequence Analysis, DNA

OBJECTIVETo establish the specific 16S-23S rRNA gene spacer regions pattern in different bacteria using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), DNA cloning and sequences analysis.

METHODSA pair of primers were selected from highly conserved sequences adjacent to the 16S-23S rRNA spacer region. Bacterial DNA of sixty-one strains of standard bacteria and corresponding clinical isolates representative of 20 genera and 27 species was amplified by PCR, and further studied by RFLP, DNA cloning and sequences analysis. Meanwhile, all specimens were examined by bacterial culturing and PCR-RFLP analysis.

RESULTSThe 27 different standard strains showed one, two, three or more than three bands. The sensitivity of PCR reached 2.5 colony-forming unit (CFU), and there was no cross reaction to the human, fungal or viral genomic DNAs. Fifteen species could be distinguished immediately by PCR, while another 10 species were further identified by Hinf I or Alu I digestion. Klebsiella pneumoniae (Kp) and Enterococcus durans (Ed) could not be differentiated from each other by Alu I or Hinf I digestion. The spacer sequences of the Kp and Ed were 908 bp and 909 bp, respectively, and they differed only at the site of the 779th nucleotide. The former was G, and the latter was A. The 760 - 790 bp sequence of Kp was as follows: CGACTGCACCGCCTCCTAC / GGCCGCGTATTC. The 760 - 790 bp sequence of Ed was as follows: CGACTGCAC CGCCTCCTAC / AGCCGCGTATTC. Only one enzyme XmaIII, could discriminate the two. The cleaving site of XmaIII is C downward arrow GGCCG. Kp DNA was cleaved into 778 bp and 130 bp fragments, while E. durans was not. Of 42 specimens with suspected septicemia, 15 were positive (35.7%) on blood culture, and 27 on PCR (64.29%). The positive rate of PCR was significantly higher than that of blood culture (P < 0.01). Of the six CSF specimens, one was positive for Staphylococcus epidermidis (Se) on culture as well as by PCR, while two specimens which were negative on cultures were positive by PCR and were diagnosed as Se according to its DNA pattern. One specimen was culture-positive for Cryptococcus neoformans (Cn) but was negative by PCR. The other two specimens were negative by both PCR and culture. Fifteen blood samples from healthy children were negative by both blood culture and PCR.

CONCLUSIONSThe method of detecting bacterial 16S-23S rRNA spacer regions using PCR-RFLP techniques was specific, sensitive, rapid and accurate in detecting pathogens in clinical bacterial infections.

Bacterial Infections ; diagnosis ; microbiology ; DNA, Bacterial ; chemistry ; genetics ; DNA, Ribosomal Spacer ; genetics ; Humans ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; RNA, Ribosomal, 16S ; genetics ; RNA, Ribosomal, 23S ; genetics ; Sequence Analysis, DNA

OBJECTIVETo set up a rapid and simple method for identificating bacteria by 16S-23SrDNA intergenic spacer regions (ISRs).

METHODSPolymorphic products of PCR from ISRs were selected on agarose gel and sequenced directly using purified fragments by excising the gel without cloning. Nucleotide sequences were compared with GenBank databases and analyzed by DNAMAN program.

RESULTSThere was only a single product in streptococcus genus after PCR amplification of 16S-23SrDNA ISRs. Five streptococcal species were obtained from 7 strains of streptococcus. Two major amplicons were consistently generated for 8 strains of Haemophilus influenzae (H. influenzae). The sequence data showed that they all belonged to H. influenzae type b on GenBank databases.

CONCLUSIONPCR and direct sequencing of 16S-23SrDNA ISRs were very successful methods for bacterial species identification.

Base Sequence ; DNA, Ribosomal Spacer ; chemistry ; Haemophilus influenzae ; genetics ; isolation & purification ; Humans ; Molecular Sequence Data ; Polymerase Chain Reaction ; methods ; RNA, Ribosomal, 16S ; genetics ; RNA, Ribosomal, 23S ; genetics ; Streptococcus ; genetics ; isolation & purification

Ribosomal RNAs are important because they catalyze the synthesis of peptides and proteins. Comparative studies of the secondary structure of 18S rRNA have revealed the basic locations of its many length-conserved and length-variable regions. In recent years, many more sequences of 18S rDNA with unusual lengths have been documented in GenBank. These data make it possible to recognize the diversity of the secondary and tertiary structures of 18S rRNAs and to identify the length-conserved parts of 18S rDNAs. The longest 18S rDNA sequences of almost every known eukaryotic phylum were included in this study. We illustrated the bioinformatics-based structure to show that, the regions that are more length-variable, regions that are less length-variable, the splicing sites for introns, and the sites of A-minor interactions are mostly distributed in different parts of the 18S rRNA. Additionally, this study revealed that some length-variable regions or insertion positions could be quite close to the functional part of the 18S rRNA of Foraminifera organisms. The tertiary structure as well as the secondary structure of 18S rRNA can be more diverse than what was previously supposed. Besides revealing how this interesting gene evolves, it can help to remove ambiguity from the alignment of eukaryotic 18S rDNAs and to improve the performance of 18S rDNA in phylogenetic reconstruction. Six nucleotides shared by Archaea and Eukaryota but rarely by Bacteria are also reported here for the first time, which might further support the supposed origin of eukaryote from archaeans.
Animals ; Base Sequence ; Drosophila melanogaster ; genetics ; Eukaryota ; classification ; Molecular Sequence Data ; Nucleic Acid Conformation ; Phylogeny ; RNA, Ribosomal, 16S ; chemistry ; genetics ; RNA, Ribosomal, 18S ; chemistry ; classification ; genetics ; Sequence Alignment ; Sequence Analysis, RNA ; Thermus thermophilus ; genetics

OBJECTIVETo compare the bacterioplankton communities in streams exposed to pollution of different types.

METHODSThe bacterioplankton communities in three selected heavily polluted streams were investigated by using terminal-restriction fragment length polymorphism (T-RFLP) analysis in combination with 16S rRNA gene clone library analysis.

RESULTSBoth T-RFLP and 16S rRNA gene clone library revealed a great difference in bacterioplankton community composition in the different streams.

CONCLUSIONThis work might provide some new insights into bioremediation of heavily polluted streams.

Bacteria ; classification ; genetics ; Biodegradation, Environmental ; Cloning, Molecular ; Ecosystem ; Environmental Monitoring ; Phylogeny ; Plankton ; physiology ; RNA, Bacterial ; genetics ; RNA, Ribosomal, 16S ; genetics ; Rivers ; chemistry ; microbiology ; Water Pollutants, Chemical

BACKGROUND: Nontuberculous mycobacteria (NTM) should be correctly identified to the species level, because of different treatment plans among NTM species. This study was performed to assess the usefulness of real-time PCR and melting curve analysis in the identification of NTM. METHODS: One hundred fifty-two clinical NTM isolates were identified to the species level by PCR-restriction fragment length polymorphism analysis (PRA). Those strains were then identified by multiplex real-time PCR and melting curve analysis on the 16S rRNA gene and hsp65 gene. RESULTS: In the 16S rRNA gene fragment analysis, M. abscessus-M. chelonae group showed melting point at temperatures above 65 degrees C and M. avium complex (MAC; M. avium and M. intracelluare) below 48 degrees C, which differentiated M. abscessus-M. chelonae group and MAC from other NTM. In the hsp65 gene fragment analysis, M. abscessus-M. chelonae group was clearly divided into M. abscessus type I, M. abscessus type II, and M. chelonae according to the melting points at 61.25 degrees C, 66.06 degrees C, and 57.58 degrees C, respectively. CONCLUSIONS: With the multiplex real-time PCR and melting curve analysis of 16S rRNA and hsp65 genes, M. abscessus and M. chelonae were readily identified and MAC were differentiated from other NTM. Especially, M. abscessus and M. chelonae, which were not differentiated from each other with the 16S rRNA gene fragment analysis, were identified with hsp65 gene fragment analysis.
Bacterial Proteins/genetics ; Chaperonins/genetics ; Computer Systems ; DNA, Bacterial/chemistry ; Mycobacteria, Atypical/genetics/*isolation & purification ; Nucleic Acid Denaturation ; Polymerase Chain Reaction/*methods ; RNA, Ribosomal, 16S/genetics

Salinity is the most important factor for the growth of crops. It is an effective method to alleviate the toxic effect caused by salt stress using saline-alkali-tolerant and growth-promoting bacteria in agriculture. Seven salt-tolerant bacteria were screened from saline-alkali soil, and the abilities of EPS production, alkalinity reduction and IAA production of the selected strains were investigated. A dominant strain DB01 was evaluated. The abilities of EPS production, alkalinity reduction and IAA production of strain DB01 were 0.21 g/g, 8.7% and 8.97 mg/L, respectively. The isolate was identified as Halomonas aquamarina by partial sequencing analysis of its 16S rRNA genes, and had the ability to inhibit the growth of Fusarium oxysporum f. sp., Alternaria solani, Phytophthora sojae and Rhizoctonia cerealis. It also could promote root length and germination rate of wheat seedlings under salt stress. Halomonas aquamarina can provide theoretical basis for the development of soil microbial resources and the application in saline-alkali soil improvement.
Alkalies ; metabolism ; Bacteria ; drug effects ; genetics ; Halomonas ; genetics ; Plant Roots ; microbiology ; RNA, Ribosomal, 16S ; genetics ; Salt Tolerance ; genetics ; Seedlings ; growth & development ; microbiology ; Soil ; chemistry ; Soil Microbiology ; Triticum ; microbiology