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1.
Eur J Clin Microbiol Infect Dis ; 34(4): 745-51, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25431363

RESUMO

For easy handling and speed of lung diseases diagnostics, approaches based on volatile organic compounds (VOCs), including those emitted by pathogenic microorganisms, are considered but currently require considerable sampling efforts. We tested whether easy-to-handle and fast detection of lung infections is possible using solid-phase microextraction (SPME) of 100 ml of exhaled breath. An analytical procedure for the detection of VOCs from the headspace of epithelial lung cells infected with four human pathogens was developed. The feasibility of this method was tested in a cystic fibrosis (CF) outpatient clinic in vivo. Exhaled breath was extracted by SPME and analyzed by gas chromatography-mass spectrometry (GC-MS). The compositions of VOCs released in the infection model were characteristic for all individual pathogens tested. Exhaled breath of CF patients allowed clear distinction of CF patients and controls by their VOC compositions using multivariate analyses. Interestingly, the major specific VOCs detected in the exhaled breath of infected CF patients in vivo differed from those monitored during bacterial in vitro growth. SPME extraction of VOCs from 100 ml of human breath allowed the distinction between CF patients and healthy probands. Our results highlight the importance of assessing the entire pattern of VOCs instead of selected biomarkers for diagnostic purposes, as well as the need to use clinical samples to identify reliable biomarkers. This study provides the proof-of-concept for the approach using the composition of exhaled VOCs in human breath for the rapid identification of infectious agents in patients with lower respiratory tract infections.


Assuntos
Infecções Bacterianas/diagnóstico , Testes Respiratórios/métodos , Fibrose Cística/complicações , Adulto , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Pessoa de Meia-Idade , Manejo de Espécimes/métodos , Fatores de Tempo , Compostos Orgânicos Voláteis/análise
2.
Curr Med Chem ; 19(21): 3564-77, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22709011

RESUMO

Diketopiperazines are the smallest cyclic peptides known. 90% of Gram-negative bacteria produce diketopiperazines and they have also been isolated from Gram-positive bacteria, fungi and higher organisms. Biosynthesis of cyclodipeptides can be achieved by dedicated nonribosomal peptide synthetases or by a novel type of synthetases named cyclopeptide synthases. Since the first report in 1924 a large number of bioactive diketopiperazines was discovered spanning activities as antitumor, antiviral, antifungal, antibacterial, antiprion, antihyperglycemic or glycosidase inhibitor agents. As infections are of increasing concern for human health and resistances against existing antibiotics are growing this review focuses on the antimicrobial activities of diketopiperazines. The antibiotic bicyclomycin is a diketopiperazine and structure activity studies revealed the unique nature of this compound which was finally developed for clinical applications. The antimicrobial activities of a number of other diketopiperazines along with structure activity relationships are discussed. Here a special focus is on the activity-toxicity problem of many compounds setting tight limitations to their application as drugs. Not only these classical antimicrobial activities but also proposed action in modulating bacterial communication as a new target to control biofilms will be evaluated. Pathogens organized in biofilms are difficult to eradicate because of the increase of their tolerance for antibiotics for several orders. Diketopiperazines were reported to modulate LuxR-mediated quorum-sensing systems of bacteria, and they are considered to influence cell-cell signaling offering alternative ways of biofilm control by interfering with microbial communication. Concluding the review we will finally discuss the potential of diketopiperazines in the clinic to erase biofilm infections.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Dicetopiperazinas/farmacologia , Fungos/efeitos dos fármacos , Antibacterianos/química , Antifúngicos/química , Dicetopiperazinas/química , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade
3.
Braz. j. microbiol ; 42(4)Oct.-Dec. 2011.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469568

RESUMO

We report the antibiofilm activity by the sponge-associated bacterium Cobetia marina upon Staphylococcus epidermidis clinical isolates obtained from central venous catheters. Antibiofilm activity/antimicrobial susceptibility correlation might predict the action of the metabolite(s) upon Staphylococcus epidermidis in the clinic, making it a possible adjuvant in therapies against biofilm-associated infections.

4.
Curr Med Chem ; 18(18): 2791-815, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21649583

RESUMO

The purine ribonucleoside adenosine (Ado) has been recognized for its regulatory functions in situations of cellular stress like ischemia, hypoxia and inflammation. The importance of extracellular Ado as a modulator in the immune system is a theme of great appreciation and the focus of recent increasing interest in the field of gastrointestinal inflammation. In this review, the different aspects of Ado signaling during inflammatory responses in the gut are discussed, considering the contribution of the four known Ado receptors (ARs; A(1), A(2A), A(2B), and A(3)), their mechanisms and expression patterns. Activation of these receptors in epithelial cells as well as in immune cells recruited to the inflamed intestinal mucosa determines the overall effect, ranging from a protective, anti-inflammatory modulation to a strong pro-inflammatory induction. Here we present the current advances in agonists and antagonists development and their potential therapeutic application studied in animal models of intestinal inflammation. In addition, alternative complementary approaches to manipulate such a complex signaling system are discussed, for example, the use of AR allosteric modulators or interference with Ado metabolism. Special features of the gut environment are taken into account: the contribution of diet components; the involvement of Ado in intestinal infections; the interactions with the gut microbiome, particularly, the recent exciting finding that an intestinal bacterium can directly produce extracellular Ado in response to host defense mechanisms in an inflammation scenario. Understanding each component of this dynamic system will broaden the possibilities for applying Ado signaling as a therapeutic target in gut inflammation.


Assuntos
Adenosina/uso terapêutico , Agonistas Adrenérgicos/uso terapêutico , Antagonistas Adrenérgicos/uso terapêutico , Doenças Inflamatórias Intestinais/tratamento farmacológico , Receptores Purinérgicos P1/metabolismo , Adenosina/química , Adenosina/farmacologia , Agonistas Adrenérgicos/química , Agonistas Adrenérgicos/farmacologia , Antagonistas Adrenérgicos/química , Antagonistas Adrenérgicos/farmacologia , Animais , Humanos , Doenças Inflamatórias Intestinais/metabolismo , Doenças Inflamatórias Intestinais/patologia , Relação Estrutura-Atividade
5.
J Appl Microbiol ; 110(4): 1065-73, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21299770

RESUMO

AIMS: To determine the kinetics of substrate fluxes in a microbial community in order to elucidate the roles of the community members. METHODS AND RESULTS: The kinetics of substrate sharing in a bacterial consortium were measured by a new analytical approach combining immunostaining, stable isotope probing and fluorescence-activated cell sorting (FACS). The bacterial consortium, consisting of four strains and growing on 4-chlorosalicylate (4-CS), was pulse-dosed with the degradation intermediate [U-(13) C]-4-chlorocatechol (4-CC). Cells were stained with strain-specific antibodies sorted by FACS and the (13) C-incorporation into fatty acids of the two most abundant members of the community was determined by isotope ratio mass spectrometry. From the two most abundant strains, the primary degrader Pseudomonas reinekei MT1 incorporated the labelled substrate faster than strain Achromobacter spanius MT3 but the maximal incorporation in strain MT3 was almost three times higher than in MT1. CONCLUSIONS: It has been reported that strain MT1 produces 4-CC as an intermediate but has a lower LD50 for it than strain MT3; therefore, MT3 still degrades 4-CC when the concentrations of 4-CC are already too toxic, even lethal, for MT1. By degrading 4-CC, produced by MT1, MT3 protects the entire community against this toxin. The higher affinity but lower tolerance of strain MT1 for 4-chlorocatechol compared to strain MT3 explains the complementary function these two strains have in the consortium adding exceptional stability to the entire community. SIGNIFICANCE AND IMPACT OF THE STUDY: The novel approach can reveal carbon fluxes in microbial communities generating quantitative data for systems biology of the microbial community.


Assuntos
Bactérias/metabolismo , Carbono/metabolismo , Consórcios Microbianos , Bactérias/isolamento & purificação , Isótopos de Carbono , Catecóis/metabolismo , Citometria de Fluxo , Cinética , Espectrometria de Massas , Dados de Sequência Molecular , Pseudomonas/metabolismo , Salicilatos/metabolismo
6.
Eur J Clin Microbiol Infect Dis ; 30(2): 193-200, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20931254

RESUMO

Supra- and subgingival biofilm formation is considered to be mainly responsible for early implant failure caused by inflammations of periimplant tissues. Nevertheless, little is known about the complex microbial diversity and interindividual similarities around dental implants. An atraumatic assessment was made of the diversity of microbial communities around titanium implants by single strand conformation polymorphism (SSCP) analysis of the 16S rRNA gene amplicons as well as subsequent sequence analysis. Samples of adherent supra- and subgingival periimplant biofilms were collected from ten patients. Additionally, samples of sulcusfluid were taken at titanium implant abutments and remaining teeth. The bacteria in the samples were characterized by SSCP and sequence analysis. A high diversity of bacteria varying between patients and within one patient at different locations was found. Bacteria characteristic for sulcusfluid and supra- and subgingival biofilm communities were identified. Sulcusfluid of the abutments showed higher abundance of Streptococcus species than from residual teeth. Prevotella and Rothia species frequently reported from the oral cavity were not detected at the abutments suggesting a role as late colonizers. Different niches in the human mouth are characterized by specific groups of bacteria. Implant abutments are a very valuable approach to study dental biofilm development in vivo.


Assuntos
Bactérias/classificação , Biofilmes/crescimento & desenvolvimento , Portador Sadio/microbiologia , Gengiva/microbiologia , Boca/microbiologia , Infecções Relacionadas à Prótese/microbiologia , Titânio , Idoso , Idoso de 80 Anos ou mais , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
7.
Braz J Microbiol ; 42(4): 1329-33, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24031760

RESUMO

We report the antibiofilm activity by the sponge-associated bacterium Cobetia marina upon Staphylococcus epidermidis clinical isolates obtained from central venous catheters. Antibiofilm activity/antimicrobial susceptibility correlation might predict the action of the metabolite(s) upon Staphylococcus epidermidis in the clinic, making it a possible adjuvant in therapies against biofilm-associated infections.

8.
Nature ; 424(6950): 763-6, 2003 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-12917681

RESUMO

More than 50% of the Earth' s surface is sea floor below 3,000 m of water. Most of this major reservoir in the global carbon cycle and final repository for anthropogenic wastes is characterized by severe food limitation. Phytodetritus is the major food source for abyssal benthic communities, and a large fraction of the annual food load can arrive in pulses within a few days. Owing to logistical constraints, the available data concerning the fate of such a pulse are scattered and often contradictory, hampering global carbon modelling and anthropogenic impact assessments. We quantified (over a period of 2.5 to 23 days) the response of an abyssal benthic community to a phytodetritus pulse, on the basis of 11 in situ experiments. Here we report that, in contrast to previous hypotheses, the sediment community oxygen consumption doubled immediately, and that macrofauna were very important for initial carbon degradation. The retarded response of bacteria and Foraminifera, the restriction of microbial carbon degradation to the sediment surface, and the low total carbon turnover distinguish abyssal from continental-slope 'deep-sea' sediments.


Assuntos
Carbono/metabolismo , Alimentos , Sedimentos Geológicos , Animais , Bactérias/metabolismo , Biomassa , Nematoides/metabolismo , Oceanos e Mares , Consumo de Oxigênio , Fatores de Tempo
9.
Microb Ecol ; 46(2): 161-76, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14708742

RESUMO

A set of microcosm experiments was performed to assess different bioremediation strategies, i.e., biostimulation and bioaugmentation, for groundwater contaminated with chlorobenzenes. The biodegradative potential was stimulated either by the supply of electron acceptors (air, (NO3-), to increase the activity of the indigenous bacterial community, or by the addition of aerobic chlorobenzene-degrading bacteria (Pseudomonas putida GJ31, Pseudomonas aeruginosa RHO1, Pseudomonas putida F1deltaCC). Experiments were performed with natural groundwater of the aquifer of Bitterfeld, which had been contaminated with 1,2-dichlorobenzene (1,2-DCB), 1,4-dichlorobenzene (1,4-DCB), and chlorobenzene (CB). The microcosms consisted of airtight glass bottles with 800 mL of natural groundwater and were incubated under in situ temperature (13 degrees C). Behavior of the introduced strains within the indigenous bacterial community was monitored by fluorescent in situ hybridization (FISH) with species-specific oligonucleotides. Dynamics of the indigenous community and the introduced strains within the microcosms were followed by single-strand conformation polymorphism (SSCP) analysis of 16S rDNA amplicons obtained from total DNA of the microbial community. An indigenous biodegradation potential under aerobic as well as anaerobic denitrifying conditions was observed accompanied by fast and specific changes in the natural bacterial community composition. Augmentation with P. aeruginosa RHO1 did not enhance bio-degradation. In contrast, both P. putida GJ31 as well as P. putida F1deltaCC were capable of growing in groundwater, even in the presence of the natural microbial community, and thereby stimulating chlorobenzene depletion. P. putida GJ31 disappeared when the xenobiotics were depleted and P. putida F1deltaCC persisted even in the absence of CB. Detailed statistical analyses revealed that community dynamics of the groundwater microbiota were highly reproducible but specific to the introduced strain, its inoculum size, and the imposed physicochemical conditions. These findings could contribute to the design of better in situ bioremediation strategies for contaminated groundwater.


Assuntos
Bactérias Aeróbias/fisiologia , Bactérias Anaeróbias/fisiologia , Clorobenzenos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , DNA Bacteriano/análise , Hibridização in Situ Fluorescente , Dinâmica Populacional , RNA Ribossômico 16S , Solo , Abastecimento de Água
10.
J Nat Prod ; 65(7): 956-9, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12141852

RESUMO

Seven alkaloids have been isolated from Teclea trichocarpa including four, normelicopicine (1), arborinine (2), skimmianine (6), and dictamnine (7), that are reported for the first time in addition to the previously reported alkaloids melicopicine (3), tecleanthine (4), and 6-methoxytecleanthine (5). The structure of 1 was confirmed by single-crystal X-ray crystallography. Two alkaloids, 1 and 2, displayed limited in vitro activities against Plasmodium falciparum strains HB3 and K1, but there appeared to be little cross-resistance with chloroquine. Alkaloid 1 was found to have some activity against P. berghei in mice (32% suppression of parasitaemia at a dose of 25 mg x kg(-1) x day(-1)), but unlike chloroquine it did not inhibit beta-haematin formation in a cell-free system; 1 was found to have low in vitro cytotoxicity to KB cells (IC50 > 328 microM).


Assuntos
Acridinas/isolamento & purificação , Alcaloides/isolamento & purificação , Antimaláricos/isolamento & purificação , Cloroquina/análogos & derivados , Plantas Medicinais/química , Plasmodium falciparum/efeitos dos fármacos , Rutaceae/química , Acridinas/química , Acridinas/farmacologia , Alcaloides/química , Alcaloides/farmacologia , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Cloroquina/farmacologia , Cristalografia por Raios X , Eritrócitos , Feminino , Humanos , Concentração Inibidora 50 , Células KB/efeitos dos fármacos , Quênia , Espectroscopia de Ressonância Magnética , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Conformação Molecular , Estrutura Molecular , Folhas de Planta/química , Plasmodium berghei/efeitos dos fármacos , Quinolinas/química , Quinolinas/isolamento & purificação , Quinolinas/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier
12.
Int J Syst Evol Microbiol ; 51(Pt 3): 827-41, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11411704

RESUMO

Strain EDIVT, an exopolysaccharide-producing bacterium, was subjected to polyphasic characterization. The bacterium produced copious amounts of an extracellular polysaccharide, forming slimy, viscous, intensely yellow-pigmented colonies on Czapek-Dox (CZD) agar. The culture fluids of the liquid version of CZD medium were highly viscous after cultivation for 5 d. Cells of strain EDIVT were Gram-negative, catalase-positive, oxidase-negative, nonspore-forming, rod-shaped and motile. Comparisons of 16S rDNA gene sequences demonstrated that EDIVT clusters phylogenetically with the species of the genus Sphingomonas sensu stricto. The G+C content of the DNA (64.5 mol%), the presence of ubiquinone Q-10, the presence of 2-hydroxymyristic acid (14:0 2-OH) as the major hydroxylated fatty acid, the absence of 3-hydroxy fatty acids and the detection of sym-homospermidine as the major component in the polyamine pattern, together with the presence of sphingoglycolipid, supported this delineation. 16S rDNA sequence analysis indicated that strain EDIVT is most closely related (99.4% similarity) to Sphingomonas trueperi LMG 2142T. DNA-DNA hybridization showed that the level of relatedness to S. trueperi is only 45.5%. Further differences were apparent in the cellular fatty acid profile, the polar lipid pattern, the Fourier-transform infrared spectrum and whole-cell proteins and in a number of biochemical characteristics. On the basis of the estimated phylogenetic position derived from 16S rDNA sequence data, DNA-DNA reassociation and phenotypic differences, strain EDIVT (= CIP 106154T = DSM 13101T) was recognized as a new species of Sphingomonas, for which the name Sphingomonas pituitosa sp. nov. is proposed. A component analysis of the exopolysaccharide (named PS-EDIV) suggested that it represents a novel type of sphingan composed of glucose, rhamnose and an unidentified sugar. Glucuronic acid, which is commonly found in sphingans, was absent. The mean molecular mass of PS-EDIV was approximately 3 x 10(6) Da.


Assuntos
Filogenia , Polissacarídeos Bacterianos/biossíntese , Sphingomonas/classificação , Sphingomonas/fisiologia , Composição de Bases , Parede Celular/ultraestrutura , Quimiotaxia , Coenzimas , DNA Ribossômico/genética , Ácidos Graxos/análise , Glucose/análise , Dados de Sequência Molecular , Ácidos Mirísticos/análise , Hibridização de Ácido Nucleico , Polissacarídeos Bacterianos/química , RNA Ribossômico 16S/genética , Ramnose/análise , Sphingomonas/genética , Ubiquinona/análogos & derivados , Ubiquinona/análise , Viscosidade
13.
Arch Microbiol ; 175(4): 270-81, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11382223

RESUMO

Microcosms were inoculated with sediments from both a petroleum-hydrocarbon (PHC)-contaminated aquifer and from a nearby pristine aquifer and incubated under anoxic denitrifying conditions with [methyl-13C]toluene. These microcosms served as a laboratory model system to evaluate the combination of isotope (13C-labeling of polar-lipid-derived fatty acids) and molecular techniques (16S rRNA-targeting gene probes) to identify the toluene-metabolizing population. After total depletion of toluene, the following bacterial phospholipid fatty acids (PLFA) were 13C-enriched: 16:1omega7c, 16:1omega7t, 16:0, cy17:0, and 18:1omega7c. Pure culture experiments demonstrated that these compounds were also found in PLFA profiles of PHC-degrading Azoarcus spp. (beta-Proteobacteria) and related species. The origin of the CO2 evolved in the microcosms was determined by measurements of stable carbon isotope ratios. Toluene represented 11% of the total pool of mineralized substrates in the contaminated sediment and 54% in the pristine sediment. The microbial community in the microcosm incubations was characterized by using DAPI staining and whole-cell hybridization with specific fluorescently labeled 16S rRNA-targeted oligonucleotide probes. Results revealed that 6% of the DAPI-stained cells in the contaminated sediment and 32% in the pristine sediment were PHC-degrading Azoarcus spp. In biotic control microcosms (incubated under denitrifying conditions, no toluene added), Azoarcus spp. cells remained at less than 1% of the DAPI-stained cells. The results show that isotope analysis in combination with whole-cell hybridization is a promising approach to identify and to quantify denitrifying toluene degraders within microbial communities.


Assuntos
Bactérias/metabolismo , Tolueno/metabolismo , Isótopos de Carbono , Sedimentos Geológicos
14.
Curr Med Chem ; 8(6): 583-606, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11281843

RESUMO

Higher fungi are characterised by the production of macroscopic fruiting bodies to generate and to distribute their spores. These fruiting bodies are under constant threat of other organisms feeding on them. As a consequence these organisms developed a number of strategies for protection, one of them is the production of toxins. The fungal subdivision Basidiomycotina produce toxic sesquiterpenes many of them are derived from the protoilludane skeleton. This skeleton is transformed and rearranged to a large number of compounds. Some of these sesquiterpenes show interesting biological properties which may be attractive for medicinal chemistry. The overview describes the different types of bioactive fungal sesquiterpenes derived from humulene known to date in Basidiomycotina and their formation. The metabolites are discussed according to their sesquiterpene skeleton and the different metabolites are compared. Where available biological activities concerning antifungal, antibacterial, cytotoxic and enzyme inhibition data are given. Special attention was paid for the different activities of these metabolites and the attempts made to use them in medicinal chemistry. The question whether metabolites produced for the self-protection of fungi can be used for pharmaceutical applications for humans will be addressed and discussed.


Assuntos
Basidiomycota/metabolismo , Sesquiterpenos/metabolismo , Sesquiterpenos/farmacologia , Basidiomycota/química , Sesquiterpenos Monocíclicos , Relação Estrutura-Atividade , Células Tumorais Cultivadas/efeitos dos fármacos
15.
Int J Syst Evol Microbiol ; 51(Pt 1): 27-34, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11211267

RESUMO

The genus Asticcacaulis, to date, comprises two species of unicellular, stalked bacteria, developing a stalk at a site which is not coincidental with the centre of the pole of the cell. Multiplication is similar to that demonstrated by the prosthecate species of the genera Caulobacter, Brevundimonas and Maricaulis. A polyphasic approach, comprising 16S rRNA gene sequencing, lipid analysis and NaCl tolerance characterizations, was used to clarify the taxonomy of the two Asticcacaulis species. From the analysis of the 16S rRNA gene sequences, a close phylogenetic relationship between the species that comprise the genera Asticcacaulis, Caulobacter and Brevundimonas could be deduced wherein the three genera form three distinct branches. The individual genera could also be discerned by different characteristic polar lipids. The species of Asticcacaulis differed from species of Caulobacter and Brevundimonas by the lack of 1,2-diacyl-3-O-[6'-phosphatidyl-alpha-D-glucopyranosyl]glycerol. They also did not contain 1,2-di-O-acyl-3-O-[D-glucopyranosyl-(1-->4)-alpha-D-glucuronopyranosyl]glycerol, which is found in most Brevundimonas species but not in strains of the genus Caulobacter. The morphological differences seen between the two species Asticcacaulis excentricus and Asticcacaulis biprosthecium are mirrored by the observed 16S rDNA sequence similarity value of 95.3%, which is relatively low compared to the interspecies similarity values observed within the genera Brevundimonas or Caulobacter.


Assuntos
Alphaproteobacteria/classificação , Filogenia , Alphaproteobacteria/citologia , Alphaproteobacteria/genética , Alphaproteobacteria/fisiologia , Caulobacter/classificação , Caulobacter/genética , Cromatografia Gasosa , DNA Ribossômico/genética , Genes de RNAr/genética , Lipídeos/análise , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/farmacologia
16.
Int J Syst Evol Microbiol ; 51(Pt 6): 2133-2143, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11760957

RESUMO

An alkaliphilic, halotolerant, Gram-negative, heterotrophic, aerobic and rod-shaped organism was isolated from drying soda and at a water-covered site of Lake Natron, Tanzania, by means of the most-probable-number technique developed for anoxygenic, phototrophic sulfur bacteria. It had an absolute requirement for alkalinity, but not for salinity; growth occurred at salt concentrations of 0-28% (w/v), with optimal growth at 3-8% (w/v) NaCl. The bacterium preferentially metabolized volatile fatty acids and required vitamins for growth. The name Alcalilimnicola halodurans gen. nov., sp. nov. is proposed for the novel isolate, placed in the gamma-Proteobacteria within the family Ectothiorhodospiraceae on the basis of analysis of the 16S rDNA sequence, polar lipids, fatty acids and DNA base composition. Although Alcalilimnicola halodurans is closely related to the extreme anoxygenic, phototrophic sulfur bacteria of the genus Halorhodospira, it is not phototrophic.


Assuntos
Água Doce/microbiologia , Gammaproteobacteria/classificação , Sedimentos Geológicos/microbiologia , África , DNA Ribossômico , Ácidos Graxos/análise , Gammaproteobacteria/genética , Gammaproteobacteria/crescimento & desenvolvimento , Gammaproteobacteria/isolamento & purificação , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , Cloreto de Sódio
17.
Int J Syst Evol Microbiol ; 50 Pt 3: 997-1006, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10843038

RESUMO

An isolate of an acidophilic archaeon, strain YT, was obtained from a bioleaching pilot plant. The organism oxidizes ferrous iron as the sole energy source and fixes inorganic carbon as the sole carbon source. The optimal pH for growth is 1.7, although growth is observed in the range pH 1.3 to 2.2. The cells are pleomorphic and without a cell wall. 16S rRNA gene sequence analysis showed this strain to cluster phylogenetically within the order 'Thermoplasmales' sensu Woese, although with only 89.9 and 87.2% sequence identity, respectively, to its closest relatives, Picrophilus oshimae and Thermoplasma acidophilum. Other principal differences from described species of the 'Thermoplasmales' are autotrophy (strain YT is obligately autotrophic), the absence of lipid components typical of the ' Thermoplasmales' (no detectable tetraethers) and a lower temperature range for growth (growth of strain YT occurs between 15 and 45 degrees C). None of the sugars, amino acids, organic acids or other organic compounds tested was utilized as a carbon source. On the basis of the information described above, the name Ferroplasma acidiphilum gen. nov., sp. nov. is proposed for strain YT within a new family, the Ferroplasmaceae fam. nov. Strain YT is the type and only strain of F. acidiphilum. This is the first report of an autotrophic, ferrous-iron-oxidizing, cell-wall-lacking archaeon.


Assuntos
Compostos Ferrosos/metabolismo , Ferro/metabolismo , Thermoplasmales/classificação , Aerobiose , Parede Celular , Meios de Cultura , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Oxirredução , Fenótipo , Filogenia , Temperatura , Thermoplasmales/crescimento & desenvolvimento , Thermoplasmales/metabolismo , Thermoplasmales/ultraestrutura
18.
Environ Microbiol ; 2(2): 161-8, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11220302

RESUMO

Biofilm formation on a low-energy substratum floating on the surface of a water column overlying a polychlorinated biphenyl (PCB)-contaminated sandy clay soil was followed by light and electron microscopy. The biofilms that developed consisted of a dense lawn of clay aggregates, each one of which contained one or more bacteria, phyllosilicates and grains of iron oxide material, all held together by bacterial extracellular polysaccharides (EPS). The clay leaflets were arranged in the form of 'houses of cards' and gave the aggregates the appearance of 'hutches' housing the bacteria. Interestingly, although the soil is poor in carbon, and the weakly bioavailable PCBs constitute the principal source of carbon in this system, the bacteria contained electron-transparent structures presumed to be carbon storage granules. These, and the EPS material present in the hutches, indicate that carbon is not limiting in this system and, as PCBs have been found associated with the clay mineral fraction of the floating substratum, the clay particles may serve as carbon shuttles. The interesting possibilities that the 'clay hutches' may represent a 'soil microhabitat', a 'minimal nutritional sphere' and an 'effective survival unit' for autochthonous bacteria are noted. The formation of clay hutches by bacteria would seem to merit further investigation, particularly regarding their roles in bacterial processes in soil and in geological processes.


Assuntos
Bactérias/ultraestrutura , Biofilmes/crescimento & desenvolvimento , Microbiologia do Solo , Bactérias/metabolismo , Microscopia Eletrônica , Bifenilos Policlorados/metabolismo
19.
Int J Syst Bacteriol ; 49 Pt 3: 1053-73, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10425763

RESUMO

The genus Caulobacter is composed of prosthecate bacteria often specialized for oligotrophic environments. The taxonomy of Caulobacter has relied primarily upon morphological criteria: a strain that visually appeared to be a member of the Caulobacter has generally been called one without challenge. A polyphasic approach, comprising 16S rDNA sequencing, profiling restriction fragments of 16S-23S rDNA interspacer regions, lipid analysis, immunological profiling and salt tolerance characterizations, was used to clarify the taxonomy of 76 strains of the genera Caulobacter. Brevundimonas, Hyphomonas and Mycoplana. The described species of the genus Caulobacter formed a paraphyletic group with Caulobacter henricii, Caulobacter fusiformis, Caulobacter vibrioides and Mycoplana segnis (Caulobacter segnis comb. nov.) belonging to Caulobacter sensu stricto. Caulobacter bacteroides (Brevundimonas bacteroides comb. nov.), C. henricii subsp. aurantiacus (Brevundimonas aurantiaca comb. nov.), Caulobacter intermedius (Brevundimonas intermedia comb. nov.), Caulobacter subvibrioides (Brevundimonas subvibrioides comb. nov.), C. subvibrioides subsp. albus (Brevundimonas alba comb. nov.), Caulobacter variabilis (Brevundimonas variabilis comb. nov.) and Mycoplana bullata belong to the genus Brevundimonas. The halophilic species Caulobacter maris and Caulobacter halobacteroides are different from these two genera and form the genus Maricaulis gen. nov. with Maricaulis maris as the type species. Caulobacter leidyia was observed to cluster with species of the genus Sphingomonas. Caulobacter crescentus is synonymous with C. vibrioides and C. halobacteroides is synonymous with Maricaulis maris as determined by these analyses and DNA-DNA hybridization. Biomarkers discerning these different genera were determined. The necessary recombinations have been proposed and a description of Maricaulis is presented.


Assuntos
Bactérias/classificação , Caulobacter/classificação , Filogenia , Microbiologia da Água , Antígenos de Bactérias/análise , Bactérias/química , Bactérias/genética , Técnicas de Tipagem Bacteriana , Western Blotting , Caulobacter/química , Caulobacter/genética , DNA Bacteriano/química , DNA Bacteriano/genética , Água Doce/microbiologia , Genes de RNAr , Humanos , Lipídeos/análise , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética , Água do Mar/microbiologia , Análise de Sequência de DNA
20.
Biochim Biophys Acta ; 1438(2): 273-80, 1999 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-10320810

RESUMO

The structural characterization of the cyclic lipoheptapeptide surfactant lichenysin A components, produced by Bacillus licheniformis strains via the non-ribosomal pathway on a corresponding peptide synthetase, was carried out using a tandem mass spectrometry (MS/MS) under fast atom bombardment (FAB) conditions. Based on the analysis of the collision-induced fragment-ion spectrum of the single charged molecular ions of both native and partially hydrolyzed forms of lipopeptide, a new general structure of lichenysin A components was elucidated. It varies from previously proposed structure by having in the peptide portion of lipopeptide the L-Gln-1 and L-Asp-5 residues instead of L-Glu-1 and L-Asn-5. The verified chemical structure of lichenysin A was found to be reflected in the structural organization of the corresponding lichenysin A synthetase, LchA, described recently.


Assuntos
Lipoproteínas/química , Peptídeos Cíclicos/química , Bacillus/química , Estrutura Molecular , Espectrometria de Massas de Bombardeamento Rápido de Átomos
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