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The disinfection efficiencies of two chemical disinfectants, chlorine dioxide and weak acid hypochlorous water (WAHW), were examined in the soiled room and dishwashing room of a hospital infectious disease ward in Taiwan. The investigations were conducted in two seasons, namely winter and summer, in order to examine the correlation between the bioaerosol concentration and the environmental factors. In addition, a single-daily disinfection mode (SM) and a twice-daily disinfection mode (TM) were applied in this study. The results showed that the bacteria and fungi colony counts were strongly correlated with the temperature. Both disinfectants reduced the bacteria and fungi concentrations in the considered rooms. However, of the two disinfectants, the ClO2 showed a stronger disinfection effect than the WAHW. It means that when using ClO2 as the disinfectant, the disinfection efficiency of the TM treatment mode is significantly better than that of the SM treatment mode. But, when using WAHW as the disinfectant, no significant difference is found between the disinfection efficiencies of the two methods. Overall, the results showed that the application of ClO2 twice daily provided the most effective means of satisfying the Taiwan EPA guidelines for the indoor air quality of hospital medical wards.
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A 35 year-old woman had a two-year history of recurrent headache with clinical presentations of visual aura in her left visual field followed by right-sided throbbing headache. The patient suffered from a similar attack but her visual aura-like symptoms persisted for over 48 hours. The concurrent electroencephalogram demonstrated focal non-epileptiform rhythmic slow waves in the right occipital region. The magnetic resonance images showed prominent parenchymal edema in the right occipital area. The cerebral angiographic study proved a small cerebral arteriovenous malformation. This illustrated case showed that cerebral arteriovenous malformation produces headaches mimicking migraine with visual aura. The acute vascular flow change and the parenchymal edema trigger a prolonged visual aura with coinstantaneous evidence of cortical depression shown on the electroencephalogram. Keywords: Symptomatic migraine; Prolonged visual aura; Unruptured arteriovenous malformation.
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Epilepsia , Malformações Arteriovenosas Intracranianas , Transtornos de Enxaqueca , Enxaqueca com Aura , Adulto , Angiografia Cerebral , Feminino , Humanos , Malformações Arteriovenosas Intracranianas/complicações , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Lobo Occipital/diagnóstico por imagemAssuntos
Neoplasias da Mama , Feminino , Humanos , Neoplasias da Mama/complicações , Eritema/diagnóstico , Eritema/etiologia , Abdome , Dor , MamilosRESUMO
BACKGROUND: Glioma stem cells (GSCs) contribute to tumor recurrence and drug resistance. This study characterizes the tumorigenesis of CD133+ cells and their sensitivity to pharmacological inhibition. METHODS: GSCs from human U87 and rat C6 glioblastoma cell lines were isolated via magnetic cell sorting using CD133 as a cancer stem cell marker. Cell proliferation was determined using the WST-1 assay. An intracranial mouse model and bioluminescence imaging were used to assess the effects of drugs on tumor growth in vivo. RESULTS: CD133+ cells expressed stem cell markers and exhibited self-renewal and enhanced tumor formation. Minocycline (Mino) was more effective in reducing the survival rate of CD133+ cells, whereas CD133- cells were more sensitive to inhibition by the signal transducer and activator of transcription 3 (STAT3) inhibitor. Inhibition of STAT3 decreased the expression of CD133+ stem cell markers. The combination of Mino and STAT3 inhibitor synergistically reduced the cell viability of glioma cells. Furthermore, this combination synergistically suppressed tumor growth in nude mice. CONCLUSION: The results suggest that concurrent targeting of different subpopulations of glioblastoma cells may be an effective therapeutic strategy for patients with malignant glioma.
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Antineoplásicos/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Sinergismo Farmacológico , Glioblastoma/tratamento farmacológico , Minociclina/farmacologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Fator de Transcrição STAT3/antagonistas & inibidores , Antígeno AC133/metabolismo , Animais , Antibacterianos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Proliferação de Células/efeitos dos fármacos , Combinação de Medicamentos , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Ratos , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
KEY MESSAGE: miR319 was identified as a dwarf-inducing gene from Shiokari and its dwarf near isogenic line, and its transgenic rice showed a reduced plant height. This finding reveals the potential application of miR319 in future molecular breeding. It is well known that microRNAs (miRNAs) play important roles in plant physiology, especially in development and stress responses. However, little is known about the role of miRNAs in plant height. In this study, the rice cultivar Shiokari and its dwarf near isogenic line Shiokari-d6 were analysed to identify and characterize plant height-associated miRNAs. This anatomic and morphological investigation revealed that the major cause of the shorter height of Shiokari-d6 is the significantly dis-elongated internodes, particularly the second internode and those underneath it. The results of miRNA microarray profiling and real-time RT-PCR indicated that miR319 is expressed at a significantly higher level in Shiokari-d6 than in Shiokari. Transgenic rice overexpressing miR319 in Oryza sativa L. cv. Tainung 67 generated through Agrobacterium-mediated transformation had a stable dwarf phenotype regardless of whether the plants were from the T1 or T2 generation. We also found that the internodes of miR319-overexpressing rice are shortened, particularly the third internode and those underneath it. Furthermore, we identified three putative miR319 target genes that were previously uncharacterized with expression levels that were negatively correlated with the expression of miR319. In conclusion, miR319 is the first miRNA proposed to be involved in plant height regulation, and its function may influence the elongation of internodes, which leads to decreased plant height.
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MicroRNAs/genética , Oryza/crescimento & desenvolvimento , RNA de Plantas/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Fenótipo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimentoRESUMO
An Au(i)-catalyzed cyclization/1,2-rearrangement/aromatization cascade of 3-yne-1,2-diols has been successfully realized. This reaction not only provides a new and efficient strategy for the synthesis of substituted cycloalka[b]furan compounds as well as their derivatives, but might also facilitate related biological studies.
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BACKGROUND: Glioblastoma multiforme (GBM) is the most lethal primary brain tumors which remains difficult to cure despite advances in surgery, radiotherapy and chemotherapy. Therefore, the development of new drug is urgently needed. α-carboline derivatives were usually isolated from marine animals such as Britannia marine tunicate Dendrodoa grossularia and Indonesian ascidian Polycarpa aurata. In this study, we have synthesized several α-carboline compounds and examined their anti-glioma activities. RESULTS: We report that among α-carboline derivatives TJY-16 (6-acetyl-9-(3,4,5-trimethoxybenzyl)-9H-pyrido[2,3-b] indole) is the most potent α-carboline analog to induce glioma cell death with IC50 value of around 50 nM. TJY-16 decreased cell viability of glioma cells in a concentration- and time-dependent manner. Trypan blue exclusion assay showed that the reduction of cell viability was due to both cell growth inhibition and cell death. Flow cytometric analysis showed that TJY-16 induced G2/M cell cycle arrest followed by induction of sub-G1 phase. Hoechst staining detected the apoptotic features such as nuclear shrinkage and DNA condensation. Western blot analysis showed the increased level of cleaved caspase-3. The activation of caspase-8 and depolarization of mitochondrial membrane potential (ΔΨm) indicated that both extrinsic and intrinsic apoptotic pathways were involved in TJY-16-induced apoptosis. TJY-16 effectively inhibited tumor growth and induced caspase-3 activation in the xenograft tumor model of U87 glioma cells. CONCLUSIONS: Our results suggest that TJY-16 may kill glioma cells by inducing G2/M cell cycle arrest followed by apoptosis. Thus, TJY-16 is a promising agent for the treatment of malignant gliomas.
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Antineoplásicos , Apoptose/efeitos dos fármacos , DNA de Neoplasias/metabolismo , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Glioma , Pontos de Checagem da Fase M do Ciclo Celular/efeitos dos fármacos , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Glioma/tratamento farmacológico , Glioma/metabolismo , Glioma/patologia , Humanos , Urocordados/químicaRESUMO
2-Substituted-1,4,5,6-tetrahydrocyclopenta[b]pyrrole, a key structural moiety exiting in many bioactive molecules, has been shown to have excellent selective activity on COX-2. In the present study, the anti-inflammatory activity and the underlying molecular mechanism of 2-substituted-1,4,5,6-tetrahydrocyclopenta[b]pyrrole on skin inflammation were assessed by 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mice. Most of the compounds showed anti-inflammatory activity on TPA-induced skin inflammation. The anti-inflammatory activity of compound 4 showed higher anti-inflammatory activity than celecoxib (3.2-fold). Compound 4 pretreatment resulted in markedly suppression of TPA-induced IL-1ß, IL-6, TNF-α, and COX-2, respectively. Furthermore, the mechanical study indicated that the anti-inflammatory activity of compound 4 was associated with its ability to inhibit activation of factor kappa-κB (NF-κB) by blocking IκB kinase (IKK) activities. Accordingly, compound 4 could be used as a potential anti-inflammatory agent for skin inflammation.
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Anti-Inflamatórios/farmacologia , Dermatite/prevenção & controle , Acetato de Tetradecanoilforbol/toxicidade , Animais , Ciclopentanos , Dermatite/etiologia , Camundongos , NF-kappa B/metabolismo , PirróisRESUMO
While reversible histone modifications are linked to an ever-expanding range of biological functions, the demethylases for histone H4 lysine 20 and their potential regulatory roles remain unknown. Here we report that the PHD and Jumonji C (JmjC) domain-containing protein, PHF8, while using multiple substrates, including H3K9me1/2 and H3K27me2, also functions as an H4K20me1 demethylase. PHF8 is recruited to promoters by its PHD domain based on interaction with H3K4me2/3 and controls G1-S transition in conjunction with E2F1, HCF-1 (also known as HCFC1) and SET1A (also known as SETD1A), at least in part, by removing the repressive H4K20me1 mark from a subset of E2F1-regulated gene promoters. Phosphorylation-dependent PHF8 dismissal from chromatin in prophase is apparently required for the accumulation of H4K20me1 during early mitosis, which might represent a component of the condensin II loading process. Accordingly, the HEAT repeat clusters in two non-structural maintenance of chromosomes (SMC) condensin II subunits, N-CAPD3 and N-CAPG2 (also known as NCAPD3 and NCAPG2, respectively), are capable of recognizing H4K20me1, and ChIP-Seq analysis demonstrates a significant overlap of condensin II and H4K20me1 sites in mitotic HeLa cells. Thus, the identification and characterization of an H4K20me1 demethylase, PHF8, has revealed an intimate link between this enzyme and two distinct events in cell cycle progression.
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Ciclo Celular/fisiologia , Proteínas Cromossômicas não Histona/metabolismo , Histona Desmetilases/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Fatores de Transcrição/metabolismo , Adenosina Trifosfatases/química , Adenosina Trifosfatases/metabolismo , Linhagem Celular , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/deficiência , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Células HeLa , Histona Desmetilases/química , Histona Desmetilases/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/química , Fator C1 de Célula Hospedeira/genética , Fator C1 de Célula Hospedeira/metabolismo , Humanos , Metilação , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Fosforilação , Regiões Promotoras Genéticas , Estrutura Terciária de Proteína , Fatores de Transcrição/química , Fatores de Transcrição/deficiência , Fatores de Transcrição/genéticaRESUMO
BH2, a monoclonal antibody prepared against the denatured human leukocytic antigen-B27 heavy chain (HLA-B27 HC), can immunoprecipitate the misfolded HLA-B27 HC complexed with Bip in the endoplasmic reticulum and recognize the homodimerized HLA-B27 HC that is often observed on the cell membrane of patients suffered from ankylosing spondylitis (AS). However, the recognition specificity of BH2 toward the other molecules of HLA-B type and toward the different types of HLA molecules remained uncharacterized. In this study, we carried out the HLA-typing by using the Luminex Technology to characterize the recognition specificity of BH2 and analyzed the binding domain of HLA-B27 HC by BH2. Our results indicated that BH2 preferably binds to molecules of HLA-B and -C rather than HLA-A and the binding site is located within the α2 domain of HLA-B27 HC.
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Anticorpos Monoclonais/imunologia , Sítios de Ligação de Anticorpos/imunologia , Antígeno HLA-B27/imunologia , Sequência de Aminoácidos , Retículo Endoplasmático/imunologia , Humanos , Dados de Sequência Molecular , Dobramento de Proteína , Espondilite Anquilosante/imunologiaRESUMO
Nonribosomal peptides (NRPs) such as vancomycin and daptomycin are among the most effective antibiotics. While NRPs are biomedically important, the computational techniques for sequencing these peptides are still in their infancy. The recent emergence of mass spectrometry techniques for NRP analysis (capable of sequencing an NRP from small amounts of nonpurified material) revealed an enormous diversity of NRPs. However, as many NRPs have nonlinear structure (e.g., cyclic or branched-cyclic peptides), the standard de novo sequencing tools (developed for linear peptides) are not applicable to NRP analysis. Here, we introduce the first NRP identification algorithm, NRPquest, that performs mutation-tolerant and modification-tolerant searches of spectral data sets against a database of putative NRPs. In contrast to previous studies aimed at NRP discovery (that usually report very few NRPs), NRPquest revealed nearly a hundred NRPs (including unknown variants of previously known peptides) in a single study. This result indicates that NRPquest can potentially make MS-based NRP identification as robust as the identification of linear peptides in traditional proteomics.
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Antibacterianos/farmacologia , Produtos Biológicos/farmacologia , Peptídeos/farmacologia , Algoritmos , Antibacterianos/química , Bacillus/genética , Bacillus/metabolismo , Produtos Biológicos/química , Daptomicina/farmacologia , Espectrometria de Massas , Estrutura Molecular , Peptídeo Sintases/metabolismo , Peptídeos/química , Proteômica , Streptomyces/genética , Streptomyces/metabolismo , Vancomicina/farmacologiaRESUMO
Phostensin is encoded by KIAA1949. 5'-RACEanalysis has been used to identify the translation start site of phostensin mRNA, indicating that it encodes 165 amino acids with an apparent molecular weight of 26 kDa on SDS-PAGE. This low-molecular-weight phostensin is present in human peripheral blood mononuclear cells and many leukemic cell lines. Phostensin is a protein phosphatase-1(PP1) binding protein. It also contains one actin-binding motif at its C-terminal region and binds to the pointed ends of actin filaments, modulating actin dynamics. In the current study, a high-molecular-weight phostensin is identified by using immunoprecipitationin combination with a proteomic approach. This new species of phostensin is also encoded by KIAA1949 and consists of 613 amino acids with an apparent molecular weight of 110 kDa on SDS-PAGE. The low-molecular-weight and high-molecular-weight phostensins were named as phostensin-α and phostensin-ß, respectively. Although phostensin-α is the C-terminal region of phostensin-ß, it is not degraded from phostensin-ß. Phostensin-ß is capable of associating with PP1 and actin filaments, and is present in many cell lines.
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Proteína Fosfatase 1/genética , Actinas/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Células HEK293 , Humanos , Células Jurkat , Dados de Sequência Molecular , Peso Molecular , Ligação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteína Fosfatase 1/química , Proteína Fosfatase 1/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
BACKGROUND: Hepatocellular carcinoma (HCC) is the most common malignant liver disease in the world. Platelets (PLTs) are known to play a key role in the maintenance of liver homeostasis and the pathophysiological processes of a variety of liver diseases. Aspirin is the most classic antiplatelet agent. However, the molecular mechanism of platelet action and whether aspirin can affect HCC progression by inhibiting platelet activity need further study. AIM: To explore the impact of the antiplatelet effect of aspirin on the development of HCC. METHODS: Platelet-rich plasma, platelet plasma, pure platelet, and platelet lysate were prepared, and a coculture model of PLTs and HCC cells was established. CCK-8 analysis, apoptosis analysis, Transwell analysis, and real-time polymerase chain reaction (RT-PCR) were used to analyze the effects of PLTs on the growth, metastasis, and inflammatory microenvironment of HCC. RT-PCR and Western blot were used to detect the effects of platelet activation on tumor-related signaling pathways. Aspirin was used to block the activation and aggregation of PLTs both in vitro and in vivo, and the effect of PLTs on the progression of HCC was detected. RESULTS: PLTs significantly promoted the growth, invasion, epithelial-mesenchymal transition, and formation of an inflammatory microenvironment in HCC cells. Activated PLTs promoted HCC progression by activating the mitogen-activated protein kinase/protein kinase B/signal transducer and activator of transcription three (MAPK/ AKT/STAT3) signaling axis. Additionally, aspirin inhibited HCC progression in vitro and in vivo by inhibiting platelet activation. CONCLUSION: PLTs play an important role in the pathogenesis of HCC, and aspirin can affect HCC progression by inhibiting platelet activity. These results suggest that antiplatelet therapy has promising application prospects in the treatment and combined treatment of HCC.
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The early identification of vulnerable patients has the potential to improve outcomes but poses a substantial challenge in clinical practice. This study evaluated the ability of an artificial intelligence (AI)-enabled electrocardiogram (ECG) to identify hospitalized patients with a high risk of mortality in a multisite randomized controlled trial involving 39 physicians and 15,965 patients. The AI-ECG alert intervention included an AI report and warning messages delivered to the physicians, flagging patients predicted to be at high risk of mortality. The trial met its primary outcome, finding that implementation of the AI-ECG alert was associated with a significant reduction in all-cause mortality within 90 days: 3.6% patients in the intervention group died within 90 days, compared to 4.3% in the control group (4.3%) (hazard ratio (HR) = 0.83, 95% confidence interval (CI) = 0.70-0.99). A prespecified analysis showed that reduction in all-cause mortality associated with the AI-ECG alert was observed primarily in patients with high-risk ECGs (HR = 0.69, 95% CI = 0.53-0.90). In analyses of secondary outcomes, patients in the intervention group with high-risk ECGs received increased levels of intensive care compared to the control group; for the high-risk ECG group of patients, implementation of the AI-ECG alert was associated with a significant reduction in the risk of cardiac death (0.2% in the intervention arm versus 2.4% in the control arm, HR = 0.07, 95% CI = 0.01-0.56). While the precise means by which implementation of the AI-ECG alert led to decreased mortality are to be fully elucidated, these results indicate that such implementation assists in the detection of high-risk patients, prompting timely clinical care and reducing mortality. ClinicalTrials.gov registration: NCT05118035 .
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Inteligência Artificial , Eletrocardiografia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
AIM: To extend and form the "Grading of Recommendations Assessment, Development and Evaluation in Traditional Chinese Medicine" (GRADE-TCM). METHODS: Methodologies were systematically reviewed and analyzed concerning evidence-based TCM guidelines worldwide. A survey questionnaire was developed based on the literature review and open-end expert interviews. Then, we performed expert consensus, discussion meeting, opinion collection, external examination, and the GRADE-TCM was formed eventually. RESULTS: 265 Chinese and English TCM guidelines were included and analyzed. Five experts completed the open-end interviews. Ten methodological entries were summarized, screened and selected. One round of consensus was conducted, including a total of 22 experts and 220 valid questionnaire entries, concerning 1) selection of the GRADE, 2) GRADE-TCM upgrading criteria, 3) GRADE-TCM evaluation standard, 4) principles of consensus and recommendation, and 5) presentation of the GRADE-TCM and recommendation. Finally, consensus was reached on the above 10 entries, and the results were of high importance (with voting percentages ranging from 50 % to 81.82 % for "very important" rating) and strong reliability (with the Cr ranging from 0.93 to 0.99). Expert discussion meeting (with 40 experts), opinion collection (in two online platforms) and external examination (with 14 third-party experts) were conducted, and the GRADE-TCM was established eventually. CONCLUSION: GRADE-TCM provides a new extended evidence-based evaluation standard for TCM guidelines. In GRADE-TCM, international evidence-based norms, characteristics of TCM intervention, and inheritance of TCM culture were combined organically and followed. This is helpful for localization of the GRADE in TCM and internationalization of TCM guidelines.
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Medicina Baseada em Evidências , Medicina Tradicional Chinesa , Medicina Tradicional Chinesa/métodos , Reprodutibilidade dos Testes , Inquéritos e QuestionáriosRESUMO
During the early stages of sporulation, a subpopulation of Bacillus subtilis cells secrete toxins that kill their genetically identical siblings in a process termed cannibalism. One of these toxins is encoded by the sdpC gene of the sdpABC operon. The active form of the SDP toxin is a 42-amino-acid peptide with a disulfide bond which is processed from an internal fragment of pro-SdpC. The factors required for the processing of pro-SdpC into mature SDP are not known. We provide evidence that pro-SdpC is secreted via the general secretory pathway and that signal peptide cleavage is a required step in the production of SDP. We also demonstrate that SdpAB are essential to produce mature SDP, which has toxin activity. Our data indicate that SdpAB are not required for secretion, translation, or stability of SdpC. Thus, SdpAB may participate in a posttranslation step in the production of SDP. The mature form of the SDP toxin contains a disulfide bond. Our data indicate that while the disulfide bond does increase activity of SDP, it is not essential for SDP activity. We demonstrate that the disulfide bond is formed independently of SdpAB. Taken together, our data suggest that SDP production is a multistep process and that SdpAB are required for SDP production likely by controlling, directly or indirectly, cleavage of SDP from the pro-SdpC precursor.
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Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Processamento de Proteína Pós-Traducional , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genéticaRESUMO
Bacillus subtilis SDP is a peptide toxin that kills cells outside the biofilm to support continued growth. We show that purified SDP acts like endogenously produced SDP; it delays sporulation, and the SdpI immunity protein confers SDP resistance. SDP kills a variety of Gram-positive bacteria in the phylum Firmicutes, as well as Escherichia coli with a compromised outer membrane, suggesting it participates in defence of the B. subtilis biofilm against Gram-positive bacteria as well as cannibalism. Fluorescence microscopy reveals that the effect of SDP on cells differs from that of nisin, nigericin, valinomycin and vancomycin-KCl, but resembles that of CCCP, DNP and azide. Indeed, SDP rapidly collapses the PMF as measured by fluorometry and flow cytometry, which triggers the slower process of autolysis. This secondary consequence of SDP treatment is not required for cell death since the autolysin-defective lytC, lytD, lytE, lytF strain fails to be lysed but is nevertheless killed by SDP. Collapsing the PMF is an ideal mechanism for a toxin involved in cannibalism and biofilm defence, since this would incapacitate neighbouring cells by inhibiting motility and secretion of proteins and toxins. It would also induce autolysis in many Gram-positive species, thereby releasing nutrients that promote biofilm growth.
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Bacillus subtilis/citologia , Bacillus subtilis/metabolismo , Toxinas Bacterianas/metabolismo , Bacteriólise , Força Próton-Motriz , Bacillus subtilis/química , Bacillus subtilis/genética , Bactérias/química , Bactérias/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/toxicidade , Força Próton-Motriz/efeitos dos fármacosRESUMO
The function of microbial interactions is to enable microorganisms to survive by establishing a homeostasis between microbial neighbors and local environments. A microorganism can respond to environmental stimuli using metabolic exchange-the transfer of molecular factors, including small molecules and proteins. Microbial interactions not only influence the survival of the microbes but also have roles in morphological and developmental processes of the organisms themselves and their neighbors. This, in turn, shapes the entire habitat of these organisms. Here we highlight our current understanding of metabolic exchange as well as the emergence of new technologies that are allowing us to eavesdrop on microbial conversations comprising dozens to hundreds of secreted metabolites that control the behavior, survival and differentiation of members of the community. The goal of the rapidly advancing field studying multifactorial metabolic exchange is to devise a microbial 'Rosetta stone' in order to understand the language by which microbial interactions are negotiated and, ultimately, to control the outcome of these conversations.
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Bactérias/metabolismo , Animais , Bactérias/química , Ecossistema , Humanos , Fases de Leitura Aberta , FenótipoRESUMO
Fungal infections are increasing worldwide, including in the aquatic environment. Microbiota that coexist with marine life can provide protection against fungal infections by secretion of metabolites with antifungal properties. Our laboratory has developed mass spectrometric methodologies with the goal of improving our functional understanding of microbial metabolites and guiding the discovery process of anti-infective agents from natural sources. GA40, a Bacillus amyloliquefaciens strain isolated from an octocoral in Panama, displayed antifungal activity against various terrestrial and marine fungal strains. Using matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS), the molecular species produced by this microbe were visualized in a side-by-side interaction with two representative fungal strains, Aspergillus fumigatus and Aspergillus niger. The visualization was performed directly on the agar without the need for extraction. By evaluating the spatial distributions, relative intensities and m/z values of GA40 secreted metabolites in the fungal interactions and singly grown control colonies, we obtained insight into the antifungal activity of secreted metabolites. Annotation of GA40 metabolites observed in MALDI-IMS was facilitated by MS/MS networking analysis, a mass spectrometric technique that clusters metabolites with similar MS/MS fragmentation patterns. This analysis established that the predominant GA40 metabolites belong to the iturin family. In a fungal inhibition assay of A. fumigatus, the GA40 iturin metabolites were found to be responsible for the antifungal properties of this Bacillus strain.
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Antozoários/microbiologia , Antifúngicos/análise , Aspergillus fumigatus/fisiologia , Aspergillus niger/fisiologia , Bacillus/fisiologia , Animais , Bacillus/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , SimbioseRESUMO
The ability of cyanobacteria to produce complex secondary metabolites with potent biological activities has gathered considerable attention due to their potential therapeutic and agrochemical applications. However, the precise physiological or ecological roles played by a majority of these metabolites have remained elusive. Several studies have shown that cyanobacteria are able to interfere with other organisms in their communities through the release of compounds into the surrounding medium, a phenomenon usually referred to as allelopathy. Exudates from the freshwater cyanobacterium Oscillatoria sp. had previously been shown to inhibit the green microalga Chlorella vulgaris. In this study, we observed that maximal allelopathic activity is highest in early growth stages of the cyanobacterium, and this provided sufficient material for isolation and chemical characterization of active compounds that inhibited the growth of C. vulgaris. Using a bioassay-guided approach, we isolated and structurally characterized these metabolites as cyclic peptides containing several unusually modified amino acids that are found both in the cells and in the spent media of Oscillatoria sp. cultures. Strikingly, only the mixture of the two most abundant metabolites in the cells was active toward C. vulgaris. Synergism was also observed in a lung cancer cell cytotoxicity assay. The binary mixture inhibited other phytoplanktonic organisms, supporting a natural function of this synergistic mixture of metabolites as allelochemicals.