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1.
Nanomaterials (Basel) ; 12(9)2022 Apr 19.
Article in English | MEDLINE | ID: mdl-35564104

ABSTRACT

High-performance temperature sensing is a key technique in modern Internet of Things. However, it is hard to attain a high precision while achieving a compact size for wireless sensing. Recently, metamaterials have been proposed to design a microwave, wireless temperature sensor, but precision is still an unsolved problem. By combining the high-quality factor (Q-factor) feature of a EIT-like metamaterial unit and the large temperature-sensing sensitivity performance of liquid metals, this paper designs and experimentally investigates an Hg-EIT-like metamaterial unit block for high figure-of-merit (FOM) temperature-sensing applications. A measured FOM of about 0.68 is realized, which is larger than most of the reported metamaterial-inspired temperature sensors.

2.
Opt Express ; 30(4): 5498-5511, 2022 Feb 14.
Article in English | MEDLINE | ID: mdl-35209511

ABSTRACT

In this paper, we propose a new kind of optomechanical metamaterial based on a planar ELC-type absorbing structure fabricated on the low-loss flexible substrate. The nonlinear coupling mechanism and nonlinear response phenomenon of the proposed optomechanical metamaterial driven by electromagnetic induced force are analyzed theoretically. The mechanical deformation/displacement and the mechanical resonance frequency shift of the metamaterial unit deposed on the flexible substrate are also numerically and experimentally demonstrated to reveal the coupling phenomenon of electromagnetic field and mechanical field. These results will help researchers to further understand the multi-physics interactions of optomechanical metamaterials and will promote the developments of new type of metasurface for high-efficiency dynamic electromagnetic wave controlling and formatting.

3.
World J Clin Cases ; 8(4): 790-797, 2020 Feb 26.
Article in English | MEDLINE | ID: mdl-32149062

ABSTRACT

BACKGROUND: Colorectal cancer (CRC) could seriously threaten the physical and mental health of pilots. Shall they end their flying after treatment of CRC? With this study, we investigated the possibility of a gradual medical waiver for such pilots to fly aircrafts again after treatment of CRC. CASE SUMMARY: We analyzed the medical waiver and clinical data of 3 pilots with CRC, who had accepted the treatment at the Department of General Surgery, Air Force Medical Center (formerly, Air Force General Hospital) between 2013 and 2018. All 3 cases underwent a series of comprehensive treatment courses, including radical resection of CRC, sequential radiotherapy, and chemotherapy. The follow-up results were satisfactory. After passing through the high-risk period of recurrence and metastasis of CRC, they all were given a medical waiver for flying again. Medical observation showed that their flying operations were safe. CONCLUSION: The CRC treatment shall follow the guidelines for diagnosis and treatment and should simultaneously protect the combating capabilities of pilots as much as possible. It is safe for pilots with CRC, who are continuously monitored under medical observation after passing through the high-risk period of recurrence and metastasis, to undertake military flight missions again.

4.
mBio ; 10(1)2019 02 12.
Article in English | MEDLINE | ID: mdl-30755513

ABSTRACT

Self-recognition underlies sociality in many group-living organisms. In bacteria, cells use various strategies to recognize kin to form social groups and, in some cases, to transition into multicellular life. One strategy relies on a single genetic locus that encodes a variable phenotypic tag ("greenbeard") for recognizing other tag bearers. Previously, we discovered a polymorphic cell surface receptor called TraA that directs self-identification through homotypic interactions in the social bacterium Myxococcus xanthus Recognition by TraA leads to cellular resource sharing in a process called outer membrane exchange (OME). A second gene in the traA operon, traB, is also required for OME but is not involved in recognition. Our prior studies of TraA identified only six recognition groups among closely related M. xanthus isolates. Here we hypothesize that the number of traA polymorphisms and, consequently, the diversity of recognition in wild isolates are much greater. To test this hypothesis, we expand the scope of TraA characterization to the order Myxococcales From genomic sequences within the three suborders of Myxococcales, we identified 90 traA orthologs. Sequence analyses and functional characterization of traAB loci suggest that OME is well maintained among diverse myxobacterial taxonomic groups. Importantly, TraA orthologs are highly polymorphic within their variable domain, the region that confers selectivity in self-recognition. We experimentally defined 10 distinct recognition groups and, based on phylogenetic and experimental analyses, predicted >60 recognition groups among the 90 traA alleles. Taken together, our findings revealed a widespread greenbeard locus that mediates the diversity of self-recognition across the order MyxococcalesIMPORTANCE Many biological species distinguish self from nonself by using different mechanisms. Higher animals recognize close kin via complex processes that often involve the five senses, cognition, and learning, whereas some microbes achieve self-recognition simply through the activity of a single genetic locus. Here we describe a single locus, traA, in myxobacteria that governs cell-cell recognition within natural populations. We found that traA is widespread across the order Myxococcales TraA is highly polymorphic among diverse myxobacterial isolates, and such polymorphisms determine selectivity in self-recognition. Through bioinformatic and experimental analyses, we showed that traA governs many distinct recognition groups within Myxococcales This report provides an example in which a single locus influences social recognition across a wide phylogenetic range of natural populations.


Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Microbial Interactions , Myxococcales/physiology , Polymorphism, Genetic , Bacterial Outer Membrane Proteins/genetics , Computational Biology , Data Mining , Genome, Bacterial , Myxococcales/genetics , Sequence Homology
5.
PLoS One ; 14(1): e0210354, 2019.
Article in English | MEDLINE | ID: mdl-30615680

ABSTRACT

The traditional image mosaic result based on SIFT feature points extraction, to some extent, has distortion errors: the larger the input image set, the greater the spliced panoramic distortion. To achieve the goal of creating a high-quality panorama, a new and improved algorithm based on the A-KAZE feature is proposed in this paper. This includes changing the way reference image are selected and putting forward a method for selecting a reference image based on the binary tree model, which takes the input image set as the leaf node set of a binary tree and uses the bottom-up approach to construct a complete binary tree. The root node image of the binary tree is the ultimate panorama obtained by stitching. Compared with the traditional way, the novel method improves the accuracy of feature points detection and enhances the stitching quality of the panorama. Additionally, the improved method proposes an automatic image straightening model to rectify the panorama, which further improves the panoramic distortion. The experimental results show that the proposed method cannot only enhance the efficiency of image stitching processing, but also reduce the panoramic distortion errors and obtain a better quality panoramic result.


Subject(s)
Algorithms , Image Processing, Computer-Assisted/methods , Image Processing, Computer-Assisted/standards , Medical Informatics/methods , Models, Statistical , Pattern Recognition, Automated/methods , Software , Humans
6.
World J Gastroenterol ; 21(12): 3519-26, 2015 Mar 28.
Article in English | MEDLINE | ID: mdl-25834316

ABSTRACT

AIM: To explore the microRNA (miRNA) profiles and to determine the key miRNAs within the side population (SP) cells of the gastric cancer cell line MKN-45. METHODS: We used fluorescence-activated cell sorting and Hoechst 33342 labeling to obtain SP cells from the human gastric carcinoma cell line MKN-45. The miRNA expression profiles of the SP and major population (MP) cells were examined using a miRNA gene chip, and key miRNAs were obtained according to aberrant expression and the miRNAs' possible targets as predicted by bioinformatics. RESULTS: Using a significance criterion of a 1.5-fold or greater difference in expression level, we observed an increase in the expression of 34 miRNAs and a decrease in the expression of 34 miRNAs when comparing SP to MP cells. Using quantitative real-time reverse transcription-polymerase chain reaction to test for differentially expressed miRNAs combined with bioinformatics results, we found that the downregulated miRNAs, such as hsa-miR-3175 and hsa-miR-203, and the upregulated miRNAs, including hsa-miR-130a, hsa-miR-324-5p, hsa-miR-34a, and hsa-miR-25-star, may be important in maintaining and regulating the characteristics of SP cells. CONCLUSION: There are key miRNAs expressed within the SP cells of the gastric cancer cell line MKN-45, and include hsa-miR-3175, hsa-miR-203, hsa-miR-130a, hsa-miR-324-5p, hsa-miR-34a, and hsa-miR-25-star.


Subject(s)
Adenocarcinoma/metabolism , MicroRNAs/metabolism , Side-Population Cells/metabolism , Stomach Neoplasms/metabolism , Adenocarcinoma/genetics , Adenocarcinoma/pathology , Cell Line, Tumor , Computational Biology , Gene Expression Profiling/methods , Gene Expression Regulation, Neoplastic , Humans , MicroRNAs/genetics , Oligonucleotide Array Sequence Analysis , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Side-Population Cells/pathology , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology
7.
World J Gastroenterol ; 21(9): 2836-9, 2015 Mar 07.
Article in English | MEDLINE | ID: mdl-25759558

ABSTRACT

A 26-year-old man presented with migrated right lower abdominal pain and without any history of hematological systemic diseases. Blood routine test showed a leukocyte count of 22.74 × 10(9)/L, with 91.4% neutrophils, and a platelet count of 4 × 10(9)/L before admission. The case question was whether the team should proceed with surgery. Obviously, a differential diagnosis is essential before making such a decision. Acute appendicitis was easily diagnosed based on clinical findings, including migrating abdominal pain, a leukocyte count of 22.74 × 10(9)/L and the result of abdominal computed tomography scan. However, it was not clear whether the severe thrombocytopenia was primary or secondary. So smear of peripheral blood and aspiration of bone marrow were ordered to exclude hematological diseases. Neither of the tests indicated obvious pathological hematological changes. There was no hepatosplenomegaly found by ultrasound examination of the liver and spleen. Therefore, operative intervention may be a unique clinical scenario in acute severe appendicitis patients with secondary thrombocytopenia.


Subject(s)
Appendectomy , Appendicitis/surgery , Thrombocytopenia/etiology , Abdominal Pain/etiology , Adult , Appendicitis/complications , Appendicitis/diagnosis , Bone Marrow Examination , Contraindications , Diagnosis, Differential , Humans , Male , Platelet Count , Predictive Value of Tests , Risk Factors , Severity of Illness Index , Thrombocytopenia/blood , Thrombocytopenia/diagnosis , Tomography, X-Ray Computed , Treatment Outcome
8.
World J Gastroenterol ; 20(24): 7988-92, 2014 Jun 28.
Article in English | MEDLINE | ID: mdl-24976737

ABSTRACT

Necrotizing fasciitis (NF) is an uncommon, rapidly progressive, and potentially fatal infection of the superficial fascia and subcutaneous tissue. NF caused by an enterocutaneous fistula has special clinical characters compared with other types of NF. NF caused by enterocutaneous fistula may have more rapid progress and more severe consequences because of multiple germs infection and corrosion by digestive juices. We treated three cases of NF caused by postoperative enterocutaneous fistula since Jan 2007. We followed empirically the principle of eliminating anaerobic conditions of infection, bypassing or draining digestive juice from the fistula and changing dressings with moist exposed burn therapy impregnated with zinc/silver acetate. These three cases were eventually cured by debridement, antibiotics and wound management.


Subject(s)
Fasciitis, Necrotizing/microbiology , Intestinal Fistula/microbiology , Postoperative Complications/microbiology , Aged , Anti-Bacterial Agents/therapeutic use , Anti-Infective Agents, Local/therapeutic use , Bandages , Combined Modality Therapy , Debridement , Drainage , Fasciitis, Necrotizing/diagnosis , Fasciitis, Necrotizing/therapy , Humans , Intestinal Fistula/diagnosis , Intestinal Fistula/therapy , Male , Middle Aged , Postoperative Complications/diagnosis , Postoperative Complications/therapy , Reoperation , Skin Transplantation , Tomography, X-Ray Computed , Treatment Outcome
9.
J Bacteriol ; 196(10): 1807-14, 2014 May.
Article in English | MEDLINE | ID: mdl-24391054

ABSTRACT

Myxobacteria are social microbes that exhibit complex multicellular behaviors. By use of fluorescent reporters, we show that Myxococcus xanthus isolates produce long narrow filaments that are enclosed by the outer membrane (OM) and contain proteins. We show that these OM tube (OMT) structures are produced at surprisingly high levels when cells are placed in liquid medium or buffer without agitation. OMTs can be long and easily exceed multiple cell lengths. When viewed by transmission electron microscopy, their morphology varies between tubes and chain-like structures. Intermediate-like structures are also found, suggesting that OMTs may transition between these two morphotypes. In support of this, video epifluorescence microscopy found that OMTs in solution dynamically twist and jiggle. On hard surfaces, myxobacteria glide, and upon cell-cell contact, they can efficiently exchange their OM proteins and lipids by a TraAB-dependent mechanism. Although the structure of OMTs hints at a possible role as conduits for exchange, evidence is presented to the contrary. For example, abundant OMT production occurs in traA or traB mutants and when cells are grown in liquid medium, yet transfer cannot occur under these conditions. Thus, genetic and environmental conditions that promote OMT production are incongruent with OM exchange.


Subject(s)
Bacterial Outer Membrane Proteins/physiology , Cell Membrane/physiology , Myxococcus xanthus/physiology , Anti-Bacterial Agents/pharmacology , Bacteriological Techniques , Gene Expression Regulation, Bacterial/physiology , Luminescent Proteins , Microbial Interactions , Myxococcus xanthus/cytology , Myxococcus xanthus/drug effects , Staining and Labeling , Red Fluorescent Protein
10.
World J Gastroenterol ; 20(1): 250-7, 2014 Jan 07.
Article in English | MEDLINE | ID: mdl-24415879

ABSTRACT

AIM: To explore the epithelial-mesenchymal transition (EMT) in tissue from patients with Lynch syndrome, and to interpret biological behaviour of Lynch syndrome. METHODS: Sixty-eight formalin-fixed and paraffin embedded tissue blocks were analyzed in this study, including tissues from Lynch syndrome (n = 30), sporadic colorectal carcinoma (CRC) (n = 30), and tumor-adjacent tissues (n = 8). Tissue sections were stained for human mutS homolog 2 (hMSH2), human mutL homolog 1 (hMLH1), transforming growth factor-ß type II receptor (TGFßRII), E-cadherin, ß-catenin, matrix metalloproteinase-7 (MMP-7) and tissue inhibitor of metalloproteinase-2 (TIMP-2) by immunohistochemical staining. Furthermore, clinical data such as age, gender and tumor-node-metastasis stage were also collected retrospectively. RESULTS: The positive expression rates of hMSH2, hMLH1, TGFßRII, E-cadherin, ß-catenin, MMP-7 and TIMP-2 were significantly related to the depth of invasion and lymph node metastasis, but not to sex or tumour size or location. The differences in the positive expression rates of hMSH2, hMLH1, TGFßRII, E-cadherin, cytomembrane ß-catenin, cytoplasmic ß-catenin, MMP-7 and TIMP-2 were significant between sporadic CRC and Lynch syndrome. The expression of hMSH2 had a positive correlation with that of hMLH1 in Lynch syndrome and sporadic CRC. The expression of TGFßRII had a positive correlation with that of hMSH2, hMLH1 and MMP-7, and a negative correlation with that of TIMP-2. The expression of MMP-7 had a negative correlation with that of TIMP-2 in Lynch syndrome and sporadic CRC. The expression of E-cadherin was positively correlated with that of cytomembrane ß-catenin. However, the expression of cytomembrane ß-catenin was negatively correlated with that of cytoplasmic ß-catenin, and the expression of cytoplasmic ß-catenin was positively correlated with that of MMP-7. CONCLUSION: EMT may play an important role in the development and progression of Lynch syndrome. Lynch syndrome was caused by the mutations of mismatch repair genes, mainly hMSH2 and hMLH1, which also beget the mutational inactivation of TGFßRII. Therefore, the colorectal cancer of Lynch syndrome can escape the inhibitory effect of TGFß1. However, TGFß1 can up-regulate the expression of MMP-7 and down-regulate the expression of TIMP-2 in tumors by disassembling the E-cadherin/ß-catenin complex in the cytomembrane.


Subject(s)
Colorectal Neoplasms, Hereditary Nonpolyposis/pathology , Epithelial-Mesenchymal Transition , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/analysis , Biopsy , Colorectal Neoplasms, Hereditary Nonpolyposis/chemistry , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Female , Humans , Immunohistochemistry , Male , Middle Aged , Retrospective Studies , Young Adult
11.
PLoS Genet ; 9(11): e1003891, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24244178

ABSTRACT

Cell-cell recognition is a fundamental process that allows cells to coordinate multicellular behaviors. Some microbes, such as myxobacteria, build multicellular fruiting bodies from free-living cells. However, how bacterial cells recognize each other by contact is poorly understood. Here we show that myxobacteria engage in recognition through interactions between TraA cell surface receptors, which leads to the fusion and exchange of outer membrane (OM) components. OM exchange is shown to be selective among 17 environmental isolates, as exchange partners parsed into five major recognition groups. TraA is the determinant of molecular specificity because: (i) exchange partners correlated with sequence conservation within its polymorphic PA14-like domain and (ii) traA allele replacements predictably changed partner specificity. Swapping traA alleles also reprogrammed social interactions among strains, including the regulation of motility and conferred immunity from inter-strain killing. We suggest that TraA helps guide the transition of single cells into a coherent bacterial community, by a proposed mechanism that is analogous to mitochondrial fusion and fission cycling that mixes contents to establish a homogenous population. In evolutionary terms, traA functions as a rare greenbeard gene that recognizes others that bear the same allele to confer beneficial treatment.


Subject(s)
Cell Communication/genetics , Cooperative Behavior , Myxococcus xanthus/genetics , Receptors, Cell Surface/genetics , Alleles , Bacterial Outer Membrane Proteins/genetics , Molecular Sequence Data , Myxococcus xanthus/metabolism , Polymorphism, Genetic , Receptors, Cell Surface/metabolism
12.
Zhongguo Zhong Yao Za Zhi ; 38(7): 995-9, 2013 Apr.
Article in Chinese | MEDLINE | ID: mdl-23847944

ABSTRACT

OBJECTIVE: To optimize the conditions of purifying the total alkaloids in Aconitum szechenyianum with macroporous adsorption resin, and compare the content of total alkaloids and aconitine in A. szechenyianum from different producing areas, in order to provide basis for further studies. METHOD: The orthogonal experiment method was adopted for optimizing the conditions of purifying the total alkaloids in A. szechenyianum with macroporous adsorption resin. The content of total alkaloids and aconitine were determined by using the titration method. The total alkaloids in A. szechenyianum from different producing areas were purified under optimum processing conditions. Aconitine was determined by HPLC. RESULT: Different processing conditions showed different influences on the purification of total alkaloids. The optimum conditions were resin type HPD-722, ethanol concentration of 80% , and ethanol elution volume of 80 mL x min(-1). The contents of aconitine in A. szechenyianum from different producing areas--Qinghai, Maxianshan, Ningxia and Yongdeng were 0.493 5, 0.883 5, 1.527 8, 1.664 4 mg x g(-1), respectively. CONCLUSION: The optimum processing conditions used in this essay could be used for purifying the total alkaloids and aconitine. A. szechenyianum from Yongdeng and Gansu contains the highest content of aconitine.


Subject(s)
Aconitine/chemistry , Aconitum/chemistry , Alkaloids/chemistry , Drugs, Chinese Herbal/chemistry , Aconitine/isolation & purification , Adsorption , Alkaloids/isolation & purification , China , Chromatography, High Pressure Liquid/instrumentation , Chromatography, High Pressure Liquid/methods , Drugs, Chinese Herbal/isolation & purification , Porosity , Resins, Synthetic/chemistry
13.
J Zhejiang Univ Sci B ; 14(3): 216-23, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23463764

ABSTRACT

OBJECTIVE: Side population (SP) cells may play a crucial role in tumorigenesis and the recurrence of cancer. Many kinds of cell lines and tissues have demonstrated the presence of SP cells, including several gastric cancer cell lines. This study is aimed to identify the cancer stem-like cells in the SP of gastric cancer cell line MKN-45. METHODS: We used fluorescence activated cell sorting (FACS) to sort SP cells in the human gastric carcinoma cell line MKN-45 (cells labeled with Hoechst 33342) and then characterized the cancer stem-like properties of SP cells. RESULTS: This study found that the SP cells had higher clone formation efficiency than major population (MP) cells. Five stemness-related gene expression profiles, including OCT-4, SOX-2, NANOG, CD44, and adenosine triphosphate (ATP)-binding cassette transporters gene ABCG2, were tested in SP and MP cells using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Western blot was used to show the difference of protein expression between SP and MP cells. Both results show that there was significantly higher protein expression in SP cells than in MP cells. When inoculated into non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice, SP cells show higher tumorigenesis tendency than MP cells. CONCLUSIONS: These results indicate that SP cells possess cancer stem cell properties and prove that SP cells from MKN-45 are gastric cancer stem-like cells.


Subject(s)
Neoplasm Proteins/metabolism , Neoplastic Stem Cells/metabolism , Neoplastic Stem Cells/pathology , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Animals , Cell Line, Tumor , Humans , Mice , Neoplastic Stem Cells/classification , Stomach Neoplasms/classification
14.
Indian J Surg ; 75(Suppl 1): 456-9, 2013 Jun.
Article in English | MEDLINE | ID: mdl-24426647

ABSTRACT

Synchronous cancer of the stomach and rectum is very rare. In a special population of pilots, especially fighter pilots, synchronous rectal and gastric cancer is much more uncommon. We herein report a case of synchronous carcinoma of the rectum and stomach. The patient was a 44-year-old male fighter pilot who complained with bloody stool and altered bowel habits. He was diagnosed with hereditary nonpolyposis colorectal cancer with a definite family history, and subsequently he underwent simultaneous low anterior resection and distal gastrectomy with D2 lymphadenectomy. Postoperative pathologic assessment showed a poorly differentiated gastric adenocarcinoma with signet ring cell components (pT2N1M0; stage IIb) and a moderately differentiated rectal adenocarcinoma with myxoid components (pT3N0M0; stage IIa). Both tumors showed positive expression of p53, Ki-67, VEGF, carcinoembryonic antigen, MRP, TS, P-gp, and TopoII, and negative expression of c-erbB2, CD34, CD31, D2-40, S-100, FVIII, MLH1, MSH2, and MSH6 oncoproteins. Six cycles of XELOX chemotherapy and 50 Gy/25 f radiotherapy were delivered postoperatively. Now, he has returned to his work under medical observation for about 6 months. From this patient's diagnosis and treatment, we think that the gene screening should be used in pilot selection. According to the result of gene screening, we can give pertinence examinations to the target organ of genes. It is very necessary for pilots to keep keen vigilance at gastrointestinal tumors because they have to face many high-risk factors in working. As to pilots, the selection of operation should be individualized.

15.
Res Microbiol ; 163(9-10): 579-91, 2012.
Article in English | MEDLINE | ID: mdl-23123306

ABSTRACT

Myxobacteria exhibit complex social traits during which large populations of cells coordinate their behaviors. An iconic example is their response to starvation: thousands of cells move by gliding motility to build a fruiting body in which vegetative cells differentiate into spores. Here we review mechanisms that the model species Myxococcus xanthus uses for cell-cell interactions, with a focus on developmental signaling and social gliding motility. We also discuss a newly discovered cell-cell interaction whereby myxobacteria exchange their outer membrane (OM) proteins and lipids. The mechanism of OM transfer requires physical contact between aligned cells on a hard surface and is apparently mediated by OM fusion. The TraA and TraB proteins are required in both donor and recipient cells for transfer, suggesting bidirectional exchange, and TraA is thought to serve as a cell surface adhesin. OM exchange results in phenotypic changes that can alter gliding motility and development and is proposed to represent a novel microbial interacting platform to coordinate multicellular activities.


Subject(s)
Microbial Interactions , Myxococcus xanthus/physiology , Adhesins, Bacterial/metabolism , Bacterial Outer Membrane Proteins/metabolism , Lipid Metabolism , Locomotion , Myxococcus xanthus/growth & development , Myxococcus xanthus/metabolism , Signal Transduction , Spores, Bacterial/growth & development
16.
PLoS Genet ; 8(4): e1002626, 2012.
Article in English | MEDLINE | ID: mdl-22511878

ABSTRACT

Biofilms are dense microbial communities. Although widely distributed and medically important, how biofilm cells interact with one another is poorly understood. Recently, we described a novel process whereby myxobacterial biofilm cells exchange their outer membrane (OM) lipoproteins. For the first time we report here the identification of two host proteins, TraAB, required for transfer. These proteins are predicted to localize in the cell envelope; and TraA encodes a distant PA14 lectin-like domain, a cysteine-rich tandem repeat region, and a putative C-terminal protein sorting tag named MYXO-CTERM, while TraB encodes an OmpA-like domain. Importantly, TraAB are required in donors and recipients, suggesting bidirectional transfer. By use of a lipophilic fluorescent dye, we also discovered that OM lipids are exchanged. Similar to lipoproteins, dye transfer requires TraAB function, gliding motility and a structured biofilm. Importantly, OM exchange was found to regulate swarming and development behaviors, suggesting a new role in cell-cell communication. A working model proposes TraA is a cell surface receptor that mediates cell-cell adhesion for OM fusion, in which lipoproteins/lipids are transferred by lateral diffusion. We further hypothesize that cell contact-dependent exchange helps myxobacteria to coordinate their social behaviors.


Subject(s)
Bacterial Outer Membrane Proteins/genetics , Cell Communication , Cell Membrane , Lipid Metabolism , Myxococcus xanthus/genetics , Bacterial Outer Membrane Proteins/metabolism , Bacterial Proteins/genetics , Biofilms/growth & development , Cell Adhesion/genetics , Cell Communication/genetics , Cell Membrane/genetics , Cell Membrane/metabolism , Lipid Metabolism/genetics , Molecular Motor Proteins/genetics , Myxococcus xanthus/cytology , Protein Conformation , Protein Transport/genetics
17.
J Bacteriol ; 193(18): 4626-33, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21764930

ABSTRACT

Myxobacteria are predatory and are prolific producers of secondary metabolites. Here, we tested a hypothesized role that secondary metabolite antibiotics function as weapons in predation. To test this, a Myxococcus xanthus Δta1 mutant, blocked in antibiotic TA (myxovirescin) production, was constructed. This TA(-) mutant was defective in producing a zone of inhibition (ZOI) against Escherichia coli. This shows that TA is the major M. xanthus-diffusible antibacterial agent against E. coli. Correspondingly, the TA(-) mutant was defective in E. coli killing. Separately, an engineered E. coli strain resistant to TA was shown to be resistant toward predation. Exogenous addition of spectinomycin, a bacteriostatic antibiotic, rescued the predation defect of the TA(-) mutant. In contrast, against Micrococcus luteus the TA(-) mutant exhibited no defect in ZOI or killing. Thus, TA plays a selective role on prey species. To extend these studies to other myxobacteria, the role of antibiotic corallopyronin production in predation was tested and also found to be required for Corallococcus coralloides killing on E. coli. Next, a role of TA production in myxobacterial fitness was assessed by measuring swarm expansion. Here, the TA(-) mutant had a specific swarm rate reduction on prey lawns, and thus reduced fitness, compared to an isogenic TA(+) strain. Based on these observations, we conclude that myxobacterial antibiotic production can function as a predatory weapon. To our knowledge, this is the first report to directly show a link between secondary metabolite production and predation.


Subject(s)
Anti-Bacterial Agents/metabolism , Antibiosis , Myxococcales/physiology , Colony Count, Microbial , Drug Resistance, Bacterial , Escherichia coli/drug effects , Gene Knockout Techniques , Lactones/metabolism , Microbial Viability/drug effects , Micrococcus luteus/drug effects , Myxococcales/genetics , Myxococcales/metabolism
18.
Mol Microbiol ; 81(2): 315-26, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21635581

ABSTRACT

Microbial biofilms represent heterogeneous populations of cells that form intimate contacts. Within these populations cells communicate, cooperate and compete. Myxobacteria are noted for their complex social interactions, including gliding motility and lipoprotein exchange. Here, we investigated cis protein sequence and cellular behaviour requirements for lipoprotein transfer between Myxococcus xanthus cells. Specifically, an outer membrane (OM) type II signal sequence (SS) fused to the heterologous mCherry fluorescent reporter resulted in OM localization. When donor cells harbouring SS(OM)-mCherry were mixed with GFP-labelled recipient cells they developed red fluorescence. Our results surprisingly showed that a type II SS for OM localization, but not inner membrane localization, was necessary and sufficient for rapid and efficient heterologous protein transfer. Importantly, transfer did not occur in liquid or on surfaces where cells were poorly aligned. We conclude that cell-cell contact and alignment is a critical step for lipoprotein exchange. We hypothesize that protein transfer facilitates cooperative myxobacteria behaviours.


Subject(s)
Lipoproteins/metabolism , Microbial Interactions , Myxococcus xanthus/physiology , Bacterial Outer Membrane Proteins/genetics , Bacterial Outer Membrane Proteins/metabolism , Genes, Reporter , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Lipoproteins/genetics , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Microscopy, Fluorescence , Models, Biological , Myxococcus xanthus/metabolism , Protein Sorting Signals , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Staining and Labeling/methods , Red Fluorescent Protein
19.
Breast Care (Basel) ; 4(1): 43-45, 2009.
Article in English | MEDLINE | ID: mdl-20877684

ABSTRACT

SUMMARY: BACKGROUND: The aim of this study was to investigate the clinicopathologic features of male breast cancer. CASE REPORT: We present the clinicopathologic data of a 72-year-old male patient with occult breast cancer, who was diagnosed and underwent surgery in our hospital. The diagnosis was confirmed by histological examination, and the patient underwent modified radical mastectomy and axillary dissection. The histological examination showed no tumor foci in the resected breast tissue, but 2 of 15 dissected axillary lymph nodes were invaded by infiltrating ductal carcinoma. Immunohistochemistry staining was negative for both estrogen and progesterone receptors, but showed expression of p53 protein (+++), proliferating cell nuclear antigen (PCNA) (+++), Bcl-2 on-coprotein (+++), nm23 protein (++), multidrug resistance protein (MRP) (++), and human epidermal receptor (HER-2) oncoprotein (+++). 24 months after being diagnosed, the patient is alive without any residual or metastatic disease. CONCLUSIONS: Breast cancer is very rare in men, and the occurrence of occult breast cancer is even less common. Axillary metastases can present as the first manifestation of breast cancer in a male.

20.
Cases J ; 1(1): 285, 2008 Oct 30.
Article in English | MEDLINE | ID: mdl-18973653

ABSTRACT

BACKGROUND: Breast cancer is very rare in men, and the occurrence of occult breast cancer which present axillary metastasis as the first manifestation is even rarer in men. CASE PRESENTATION: We report a 72-year-old male Han-Chinese patient who presented axillary metastasis as the first manifestation of breast cancer and got correctly diagnoses by histological examination. He underwent modified radical mastectomy and axillary dissection on 11 Apr 2006. The histopathologic examination showed that no tumor focus was found in his breast tissue, but two out of fifteen of axillary lymph nodes were invaded by infiltrating ductal carcinoma. The IHC stain showed that estrogen receptor (ER) and progestin receptor (PR) were negative, Human epidermal receptor (HER-2) oncoprotein (+++), P53 protein expressed (+++), Bcl-2 oncoprotein (+++), nm23 protein (++), proliferating cell nuclear antigen (PCNA) (+++) and multidrug-resistance protein (MRP) (++). After operation, he did not receive endocrine therapy, chemotherapy and radiotherapy because of his senility. He is alive without any residual or metastasis disease 29 months after being diagnosed. CONCLUSION: This is the first case in our hospital that presents axillary metastases as the first manifestation of male breast cancer.

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