ABSTRACT
Two Gram-stain-negative, aerobic, rod-shaped, non-endospore-forming and motile bacterial strains, designated IT1137T and S025T, were isolated from an intertidal sediment sample collected from the Fildes Peninsula (King George Island, Maritime Antarctica) and a soil sample under red snow in the Ny-Ålesund region (Svalbard, High Arctic), respectively. The 16S rRNA gene sequence similarity values grouped them in the genus Pseudomonas. The two strains were characterized phenotypically using API 20E, API 20NE, API ZYM and Biolog GENIII tests and chemotaxonomically by their fatty acid contents, polar lipids and respiratory quinones. Multilocus sequence analysis (concatenated 16S rRNA, gyrB, rpoB and rpoD sequences), together with genome comparisons by average nucleotide identity and digital DNA-DNA hybridization, were performed. The results showed that the similarity values of the two isolates with the type strains of related Pseudomonas species were below the recognized thresholds for species definition. Based on polyphasic taxonomy analysis, it can be concluded that strains IT1137T and S025T represent two novel species of the genus Pseudomonas, for which the names Pseudomonas paeninsulae sp. nov. (type strain IT1137T=PMCC 100533T=CCTCC AB 2023226T=JCM 36637T) and Pseudomonas svalbardensis sp. nov. (type strain S025T=PMCC 200367T= CCTCC AB 2023225T=JCM 36638T) are proposed.
Subject(s)
Bacterial Typing Techniques , DNA, Bacterial , Fatty Acids , Geologic Sediments , Multilocus Sequence Typing , Nucleic Acid Hybridization , Phylogeny , Pseudomonas , RNA, Ribosomal, 16S , Sequence Analysis, DNA , Soil Microbiology , RNA, Ribosomal, 16S/genetics , Pseudomonas/genetics , Pseudomonas/classification , Pseudomonas/isolation & purification , Geologic Sediments/microbiology , DNA, Bacterial/genetics , Arctic Regions , Antarctic Regions , Fatty Acids/analysis , Svalbard , Base Composition , Quinones/analysisABSTRACT
Pseudomonas species are known for their diverse metabolic abilities and broad ecological distribution. They are fundamental components of bacterial communities and perform essential ecological functions in the environment. A psychrotrophic Pseudomonas sp. IT1137 was isolated from intertidal sediment in the coastal region of the Fildes Peninsula, King George Island, Antarctica. The strain contained a circular chromosome of 5,346,697 bp with a G + C content of 61.66 mol% and one plasmid of 4481 bp with a G + C content of 64.61 mol%. A total of 4848 protein-coding genes, 65 tRNA genes and 15 rRNA genes were obtained. Genome sequence analysis revealed that strain IT1137 not only is a potentially novel species of the genus Pseudomonas but also harbors functional genes related to nitrogen, sulfur and phosphorus cycling. In addition, genes involved in alkane degradation, ectoine synthesis and cyclic lipopeptide (CLP) production were detected in the bacterial genome. The results indicate the potential of the strain Pseudomonas sp. IT1137 for biotechnological applications such as bioremediation and secondary metabolite production and are helpful for understanding bacterial adaptability and ecological function in cold coastal environments.
Subject(s)
Alkanes , Cold Temperature , Genome, Bacterial , Geologic Sediments , Pseudomonas , Pseudomonas/genetics , Antarctic Regions , Geologic Sediments/microbiology , Alkanes/metabolism , Whole Genome Sequencing , Biodegradation, EnvironmentalABSTRACT
Bacteria of the genus Oceanisphaera in the class Gammaproteobacteria are widely distributed in marine environments. Oceanisphaera sp. IT1-181 was isolated from intertidal sediment in the coastal region of the Chinese Great Wall Station on the Fildes Peninsula, King George Island, Antarctica. Here, we sequenced the complete genome of strain IT1-181, which contained a single chromosome of 3,572,184 bp (G + C content of 49.89 mol%) with five plasmids. A total of 3229 protein-coding genes, 88 tRNA genes, and 25 rRNA genes were obtained. Genome sequence analysis revealed that strain IT1-181 was not only a potentially novel species of the genus Oceanisphaera, but also harbored genes involved in biosynthesizing ectoine as well as poly-ß-hydroxybutyric acid (PHB). In addition, genes of a complete type I-E CRISPR-Cas system were found in the bacterium. The results indicate the potential of strain Oceanisphaera sp. IT1-181 in biotechnology and are helpful for us understanding its ecological roles in the changing Antarctic intertidal zone environment.
Subject(s)
Aeromonadaceae , Seawater , Seawater/microbiology , Fatty Acids/analysis , Antarctic Regions , DNA, Bacterial/genetics , Phylogeny , RNA, Ribosomal, 16S , Bacterial Typing Techniques , Plasmids/genetics , Bacteria/genetics , Aeromonadaceae/genetics , Sequence Analysis, DNAABSTRACT
BACKGROUND: Biological denitrification has been commonly adopted for the removal of nitrogen from sewage effluents. However, due to the low temperature during winter, microorganisms in the wastewater biological treatment unit usually encounter problems such as slow cell growth and low enzymatic efficiency. Hence, the isolation and screening of cold-tolerant aerobic denitrifying bacteria (ADB) have recently drawn attention. In our previous study, two Pseudomonas strains PMCC200344 and PMCC200367 isolated from Arctic soil demonstrated strong denitrification ability at low temperatures. The two Arctic strains show potential for biological nitrogen removal from sewage in cold environments. However, the genome sequences of these two organisms have not been reported thus far. RESULTS: Here, the basic characteristics and genetic diversity of strains PMCC200344 and PMCC200367 were described, together with the complete genomes and comparative genomic results. The genome of Pseudomonas sp. PMCC200344 was composed of a circular chromosome of 6,478,166 bp with a G + C content of 58.60% and contained a total of 5,853 genes. The genome of Pseudomonas sp. PMCC200367 was composed of a circular chromosome of 6,360,061 bp with a G + C content of 58.68% and contained 5,801 genes. Not only prophages but also genomic islands were identified in the two Pseudomonas strains. No plasmids were observed. All genes of a complete set of denitrification pathways as well as various putative cold adaptation and heavy metal resistance genes in the genomes were identified and analyzed. These genes were usually detected on genomic islands in bacterial genomes. CONCLUSIONS: These analytical results provide insights into the genomic basis of microbial denitrification in cold environments, indicating the potential of Arctic Pseudomonas strains in nitrogen removal from sewage effluents at low temperatures.
Subject(s)
Denitrification , Sewage , Comparative Genomic Hybridization , Genomics , Nitrogen , Pseudomonas/geneticsABSTRACT
BACKGROUND: Bacterial meningitis (BM) is a common central nervous system inflammatory disease. BM may cause serious complications, and early diagnosis is essential to improve the prognosis of affected patients. CASE SUMMARY: A 37-year-old man was hospitalized with purulent meningitis because of worsening headache for 12 h, accompanied by vomiting, fever, and rhinorrhea. Head computed tomography showed a lesion in the left frontal lobe. Infectious disease screening showed positivity for hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B core antigen. Cerebrospinal fluid (CSF) leak was suspected based on clinical history. Streptococcus pneumoniae (S. pneumoniae) was detected in CSF by metagenomic next-generation sequencing (mNGS) technology, confirming the diagnosis of purulent BM. After treatment, multiplex PCR indicated the presence of hepatitis B virus (HBV) DNA and absence of S. pneumoniae DNA in CSF samples. CONCLUSION: We report a rare case of HBV in the CSF of a patient with purulent BM. Multiplex PCR is more sensitive than mNGS for detecting HBV DNA.
ABSTRACT
Veins are easy to obtain, have low immunogenicity, and induce a relatively weak inflammatory response. Therefore, veins have the potential to be used as conduits for nerve regeneration. However, because of the presence of venous valves and the great elasticity of the venous wall, the vein is not conducive to nerve regeneration. In this study, a novel tissue engineered nerve graft was constructed by combining normal dissected nerve microtissue with an autologous vein graft for repairing 10-mm peripheral nerve defects in rats. Compared with rats given the vein graft alone, rats given the tissue engineered nerve graft had an improved sciatic static index, and a higher amplitude and shorter latency of compound muscle action potentials. Furthermore, rats implanted with the microtissue graft had a higher density and thickness of myelinated nerve fibers and reduced gastrocnemius muscle atrophy compared with rats implanted with the vein alone. However, the tissue engineered nerve graft had a lower ability to repair the defect than autogenous nerve transplantation. In summary, although the tissue engineered nerve graft constructed with autologous vein and nerve microtissue is not as effective as autologous nerve transplantation for repairing long-segment sciatic nerve defects, it may nonetheless have therapeutic potential for the clinical repair of long sciatic nerve defects. This study was approved by the Experimental Animal Ethics Committee of Chinese PLA General Hospital (approval No. 2016-x9-07) on September 7, 2016.
ABSTRACT
BACKGROUND: Autoimmune encephalitis associated with antibodies against γ-aminobutyric acid B receptor (GABA B R) in patients with limbic encephalitis (LE) was first described in 2010. We present a series of Han Chinese patients for further clinical refinement. METHODS: Serum and cerebrospinal fluid (CSF) samples from patients referred to the program of encephalitis and paraneoplastic syndrome of Peking Union Medical College Hospital were tested with indirect immunofluorescence. Clinical information of patients with anti-GABA B R antibody positivity was retrospectively reviewed, and descriptive statistical analysis was performed. RESULTS: All eighteen anti-GABA B R antibody-positive cases had limbic syndromes, and electroencephalogram (EEG) or neuroimaging evidence fulfilled the diagnostic criteria of LE. Four patients had additional antibodies against Hu in serum and one had anti-N-methyl-d-aspartate receptor antibody in both sera and CSF. Seventeen (17/18) patients presented with new-onset refractory seizure or status epileptics. Twelve (12/18) patients had memory deficits, 11 (11/18) patients had personality change, 7 (7/18) patients had disturbance of consciousness, and 3 (3/18) patients showed cerebellar dysfunction. One patient with LE had progressive motor and sensory polyneuropathy. Lung cancer was detected in 6 (6/18) patients. Ten (10/18) patients showed abnormality in bilateral or unilateral mediotemporal region on magnetic resonance imaging. Ten (10/18) patients had temporal lobe epileptic activity with or without general slowing on EEG. Seventeen patients received immunotherapy and 15 of them showed neurological improvement. Four patients with lung cancer died within 1-12 months due to neoplastic complications. CONCLUSIONS: Our study demonstrates that most Han Chinese patients with anti-GABA B R antibody-associated LE have prominent refractory epilepsy and show neurological improvement on immunotherapy. Patients with underlying lung tumor have a relatively poor prognosis. Testing for anti-GABA B R antibodies is necessary for patients with possible LE or new-onset epilepsy with unknown etiology.
Subject(s)
Autoantibodies/immunology , Epilepsy/immunology , Epilepsy/pathology , Limbic Encephalitis/immunology , Limbic Encephalitis/pathology , Receptors, N-Methyl-D-Aspartate/immunology , Adult , China , Electroencephalography , Female , Humans , Male , Middle Aged , Retrospective Studies , gamma-Aminobutyric Acid/metabolismABSTRACT
Based on microarray hybridization, a diagnostic test for coronavirus infection was developed using eight coronavirus strains: canine coronavirus (CCoV), feline infectious peritonitis virus (FIPV), feline coronavirus (FCoV), bovine coronavirus (BCoV), porcine respiratory coronavirus (PRCoV), turkey enteritis coronavirus (TCoV), transmissible gastroenteritis virus (TGEV), and human respiratory coronavirus (HRCoV). Up to 104 cDNA clones of eight viruses were obtained by reverse transcription PCR with different pairs of primers designed for each virus and a pair of universal primers designed for the RNA polymerase gene of coronavirus. Total RNAs extracted from virus were reverse transcribed, followed by multi-PCR amplification and labeled with Cy3-dCTP. All labeled cDNAs and prepared gene chips were subjected to specific hybridization. The results showed that extensive cross-reaction existed between CCoV, FCoV, FIPV, TGEV and PRCoV, while there was no cross-reaction between BCoV, TCoV and HRCoV. The ultimate specific gene chip was developed with DNA fragments reamplified from the chosen recombinant plasmids without cross-reaction between different coronaviruses. The hybridization results showed that this gene chip could specifically identify and distinguish the eight coronaviruses and the sensitivity of the chip may be 1,000x more sensitive than PCR, indicating that it can be used for the diagnosis of eight coronavirus infections at the same time.