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1.
PLoS One ; 16(9): e0257800, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34582496

RESUMO

Copper is prevalent in coastal ecosystems due to its use as an algaecide and as an anti-fouling agent on ship hulls. Alteromonas spp. have previously been shown to be some of the early colonizers of copper-based anti-fouling paint but little is known about the mechanisms they use to overcome this initial copper challenge. The main models of copper resistance include the Escherichia coli chromosome-based Cue and Cus systems; the plasmid-based E. coli Pco system; and the plasmid-based Pseudomonas syringae Cop system. These were all elucidated from strains isolated from copper-rich environments of agricultural and/or enteric origin. In this work, copper resistance assays demonstrated the ability of Alteromonas macleodii strains CUKW and KCC02 to grow at levels lethal to other marine bacterial species. A custom database of Hidden Markov Models was designed based on proteins from the Cue, Cus, and Cop/Pco systems and used to identify potential copper resistance genes in CUKW and KCC02. Comparative genomic analyses with marine bacterial species and bacterial species isolated from copper-rich environments demonstrated that CUKW and KCC02 possess genetic elements of all systems, oftentimes with multiple copies, distributed throughout the chromosome and mega-plasmids. In particular, two copies of copA (the key player in cytoplasmic detoxification), each with its own apparent MerR-like transcriptional regulator, occur on a mega-plasmid, along with multiple copies of Pco homologs. Genes from both systems were induced upon exposure to elevated copper levels (100 µM- 3 mM). Genomic analysis identified one of the merR-copA clusters occurs on a genomic island (GI) within the plasmid, and comparative genomic analysis found that either of the merR-copA clusters, which also includes genes coding for a cupredoxin domain-containing protein and an isoprenylcysteine methyltransferase, occurs on a GI across diverse bacterial species. These genomic findings combined with the ability of CUKW and KCC02 to grow in copper-challenged conditions are couched within the context of the genome flexibility of the Alteromonas genus.


Assuntos
Alteromonas/crescimento & desenvolvimento , Organismos Aquáticos/microbiologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana , Alteromonas/efeitos dos fármacos , Alteromonas/genética , Alteromonas/isolamento & purificação , Cromossomos Bacterianos/genética , Cobre/farmacologia , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Cadeias de Markov , Plasmídeos/genética , Análise de Sequência de RNA , Sequenciamento Completo do Genoma
2.
Mar Pollut Bull ; 172: 112895, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34455348

RESUMO

To determine how bacterial communities succeed after the initial attachment of the bacterial biofilm adhesion using 16S rDNA meta-barcoding in plates coated with copper-based anti-fouling (AF) and non-AF (control) coatings as well as ambient seawater, coated plates were submerged in a marine environment in situ. Alteromonas genovensis (Gammaproteobacteria) in AF coating and Pacificibacter sp. (Alphaproteobacteria) in the control plate were initially abundant. In the AF coating, the abundance of A. genovensis decreased rapidly, whereas that of genus Phaeobacter (Alphaproteobacteria), Serratia (Gammaproteobacteria) and Cupriavidus (Betaproteobacteria) increased. Bacterial community in the control plate had a strong connection to pathogenic Vibrio spp. associated with the growth of invertebrates. Therefore, in the in situ AF coating experiment, A. genovensis accumulation was initially and intensively increased, and the bacteria responded to chemical antagonism, induced the proliferation of specific biofilm bacteria and influenced the interactions and recruitment of additional bacterial communities.


Assuntos
Incrustação Biológica , Alteromonas , Bactérias , Biofilmes , Incrustação Biológica/prevenção & controle , Pintura
3.
Ecotoxicol Environ Saf ; 222: 112522, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34304132

RESUMO

Arsenic (As) contamination of freshwater resources constitutes a major environmental issue affecting over 200 million people worldwide. Although the use of microorganisms for the bioremediation of As has been well studied, only very few candidates have been identified to date. Here, we investigated bacteria associated with the Red Sea sponge Theonella swinhoei and their potential to reduce As in a low-salinity liquid medium. This Indo-Pacific common sponge has been shown to hyper-accumulate As, at an average concentration of 8600 mg/g-1 in an environment uncontaminated by arsenic or barium. Four isolated strains of bacteria exhibited arsenic reduction potential by transforming inorganic As in the form of arsenate (iAsV) to arsenite (iAsIII). Two of these isolates were identified as Alteromonas macleodii and Pseudovibrio ascidisceicola, and the other two isolates, both belonging to the same species, were identified as Pseudovibrio denitrificans. The four isolates were then cultured in a low-salinity iAsV-rich medium (5 mM) and As concentration was measured over time using a specifically designed high-performance liquid chromatograph coupled to a mass spectrometer (HPLC-MS). Out of the four isolates, A. macleodii and P. ascidisceicola grew successfully in a low-salinity liquid medium and reduced AsV to AsIII at an average rate of 0.094 and 0.083 mM/h, respectively, thereby demonstrating great potential for the bioremediation of As-contaminated groundwater.


Assuntos
Arsênio , Rhodobacteraceae , Theonella , Alteromonas , Animais , Arseniatos , Biodegradação Ambiental , Humanos , Filogenia , RNA Ribossômico 16S
4.
Syst Appl Microbiol ; 44(4): 126226, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34171620

RESUMO

In the course of a bioprospective study of marine prokaryotes for cosmetic purposes, four strains, MD_567T, MD_652T, MD_674 and PS_109T, were isolated that 16S rRNA gene affiliation indicated could represent three new species within the family Alteromonadaceae. A thorough phylogenetic, genomic and phenotypic taxonomic study confirmed that the isolates could be classified as three new taxa for which we propose the names Alteromonas antoniana sp. nov., Alteromonas lipotrueae sp. nov. and Alteromonas lipotrueiana sp. nov. In addition, the consistent monophyletic nature of the members of the genera Alteromonas and Salinimonas showed that both taxa should be unified, and therefore we also propose the reclassification of the genus Salinimonas within Alteromonas, as well as new combinations for the species of the former. As the specific epithets profundi and sediminis are already used for Alteromonas species, we created the nomina nova "Alteromonas alteriprofundi" nom. nov. and Alteromonas alterisediminis nom. nov. to accommodate the new names for "Salinimonas profundi" and Salinimonas sediminis. Whole genome comparisons also allowed us to detect the unexpected codification of aromatic hydrocarbon biodegradative compounds, such as benzoate and catechol, whose activity was then demonstrated phenotypically. Finally, the high genomic identity between the type strains of Alteromonas stellipolaris and Alteromonas addita indicated that the latter is a junior heterotypic synonym of Alteromonas stellipolaris.


Assuntos
Alteromonas , Filogenia , Água do Mar/microbiologia , Alteromonadaceae , Alteromonas/classificação , Alteromonas/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
5.
Viruses ; 13(6)2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073246

RESUMO

Bacteriophages substantially contribute to bacterial mortality in the ocean and play critical roles in global biogeochemical processes. Alteromonas is a ubiquitous bacterial genus in global tropical and temperate waters, which can cross-protect marine cyanobacteria and thus has important ecological benefits. However, little is known about the biological and ecological features of Alteromonas phages (alterophages). Here, we describe a novel alterophage vB_AmeP-R8W (R8W), which belongs to the Autographiviridae family and infects the deep-clade Alteromonas mediterranea. R8W has an equidistant and icosahedral head (65 ± 1 nm in diameter) and a short tail (12 ± 2 nm in length). The genome size of R8W is 48,825 bp, with a G + C content of 40.55%. R8W possesses three putative auxiliary metabolic genes encoding proteins involved in nucleotide metabolism and DNA binding: thymidylate synthase, nucleoside triphosphate pyrophosphohydrolase, and PhoB. R8W has a rapid lytic cycle with a burst size of 88 plaque-forming units/cell. Notably, R8W has a wide host range, such that it can infect 35 Alteromonas strains; it exhibits a strong specificity for strains isolated from deep waters. R8W has two specific receptor binding proteins and a compatible holin-endolysin system, which contribute to its wide host range. The isolation of R8W will contribute to the understanding of alterophage evolution, as well as the phage-host interactions and ecological importance of alterophages.


Assuntos
Alteromonas/virologia , Bacteriófagos/fisiologia , Especificidade de Hospedeiro , Bacteriófagos/isolamento & purificação , Bacteriófagos/ultraestrutura , Biologia Computacional/métodos , Genoma Viral , Genômica/métodos , Modelos Moleculares , Anotação de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Conformação Proteica , Relação Estrutura-Atividade , Proteínas Virais/química , Proteínas Virais/genética
6.
ISME J ; 15(11): 3375-3383, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34050259

RESUMO

Alkaline phosphatase (APase) is one of the marine enzymes used by oceanic microbes to obtain inorganic phosphorus (Pi) from dissolved organic phosphorus to overcome P-limitation. Marine APase is generally recognized to perform P-monoesterase activity. Here we integrated a biochemical characterization of a specific APase enzyme, examination of global ocean databases, and field measurements, to study the type and relevance of marine APase promiscuity. We performed an in silico mining of phoA homologs, followed by de novo synthesis and heterologous expression in E. coli of the full-length gene from Alteromonas mediterranea, resulting in a recombinant PhoA. A global analysis using the TARA Oceans, Malaspina and other metagenomic databases confirmed the predicted widespread distribution of the gene encoding the targeted PhoA in all oceanic basins throughout the water column. Kinetic assays with the purified PhoA enzyme revealed that this enzyme exhibits not only the predicted P-monoester activity, but also P-diesterase, P-triesterase and sulfatase activity as a result of a promiscuous behavior. Among all activities, P-monoester bond hydrolysis exhibited the highest catalytic activity of APase despite its lower affinity for phosphate monoesters. APase is highly efficient as a P-monoesterase at high substrate concentrations, whereas promiscuous activities of APase, like diesterase, triesterase, and sulfatase activities are more efficient at low substrate concentrations. Strong similarities were observed between the monoesterase:diesterase ratio of the purified PhoA protein in the laboratory and in natural seawater. Thus, our results reveal enzyme promiscuity of APase playing potentially an important role in the marine phosphorus cycle.


Assuntos
Fosfatase Alcalina , Alteromonas , Fosfatase Alcalina/genética , Escherichia coli , Oceanos e Mares
7.
Mar Drugs ; 19(3)2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33806830

RESUMO

Antimetastatic properties on both murine and human osteosarcoma cell lines (POS-1 and KHOS) have been evidenced using exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium. These derivatives had no significant effect on the cell cycle neither a pro-apoptotic effect on osteosarcoma cells. Based on this observation, these EPSs could be employed as new drug delivery systems for therapeutic uses. A theranostic approach, i.e., combination of a predictive biomarker with a therapeutic agent, has been developed notably by combining with true pair of theranostic radionuclides, such as scandium 47Sc/44Sc. However, it is crucial to ensure that, once complexation is done, the biological properties of the vector remain intact, allowing the molecular tropism of the ligand to recognize its molecular target. It is important to assess if the biological properties of EPS evidenced on osteosarcoma cell lines remain when scandium is complexed to the polymers and can be extended to other cancer cell types. Scandium-EPS complexes were thus tested in vitro on human cell lines: MNNG/HOS osteosarcoma, A375 melanoma, A549 lung adenocarcinoma, U251 glioma, MDA231 breast cancer, and Caco2 colon cancer cells. An xCELLigence Real Cell Time Analysis (RTCA) technology assay was used to monitor for 160 h, the proliferation kinetics of the different cell lines. The tested complexes exhibited an anti-proliferative effect, this effect was more effective compared to EPS alone. This increase of the antiproliferative properties was explained by a change in conformation of EPS complexes due to their polyelectrolyte nature that was induced by complexation. Alterations of both growth factor-receptor signaling, and transmembrane protein interactions could be the principal cause of the antiproliferative effect. These results are very promising and reveal that EPS can be coupled to scandium for improving its biological effects and also suggesting that no major structural modification occurs on the ligand.


Assuntos
Alteromonas/metabolismo , Proliferação de Células/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Polissacarídeos Bacterianos/farmacologia , Escândio/farmacologia , Células A549 , Animais , Células CACO-2 , Complexos de Coordenação , Heparina/farmacologia , Humanos , Cinética , Camundongos , Neoplasias/patologia , Polissacarídeos Bacterianos/isolamento & purificação
8.
Mar Drugs ; 19(3)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802659

RESUMO

The alginate lyases have unique advantages in the preparation of alginate oligosaccharides and processing of brown algae. Herein, a gene alg2951 encoding a PL7 family alginate lyase with exo/endo-type activity was cloned from a novel marine bacterium Alteromonas portus HB161718T and then expressed in Escherichia coli. The recombinant Alg2951 in the culture supernatant reached the activity of 63.6 U/mL, with a molecular weight of approximate 60 kDa. Alg2951 exhibited the maximum activity at 25 °C and pH 8.0, was relatively stable at temperatures lower than 30 °C, and showed a special preference to poly-guluronic acid (polyG) as well. Both NaCl and KCl had the most promotion effect on the enzyme activity of Alg2951 at 0.2 M, increasing by 21.6 and 19.1 times, respectively. The TCL (Thin Layer Chromatography) and ESI-MS (Electrospray Ionization Mass Spectrometry) analyses suggested that Alg2951 could catalyze the hydrolysis of sodium alginate to produce monosaccharides and trisaccharides. Furthermore, the enzymatic hydrolysates displayed good antioxidant activity by assays of the scavenging abilities towards radicals (hydroxyl and ABTS+) and the reducing power. Due to its cold-adapted and dual exo/endo-type properties, Alg2951 can be a potential enzymatic tool for industrial production.


Assuntos
Alteromonas/enzimologia , Antioxidantes/farmacologia , Polissacarídeo-Liases/isolamento & purificação , Alginatos/metabolismo , Antioxidantes/química , Antioxidantes/isolamento & purificação , Clonagem Molecular , Temperatura Baixa , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Peso Molecular , Polissacarídeo-Liases/genética , Polissacarídeo-Liases/farmacologia , Temperatura
9.
Molecules ; 26(4)2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33672781

RESUMO

(1) Background: Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties. They may represent a new class of ligands to be combined with theranostic radionuclides, such as 47Sc/44Sc. The goal of this work was to investigate the feasibility of such coupling. (2) Methods: EPSs, as well as heparin used as a drug reference, were characterized in terms of molar mass and dispersity using Asymmetrical Flow Field-Flow Fractionation coupled to Multi-Angle Light Scattering (AF4-MALS). The intrinsic viscosity of EPSs at different ionic strengths were measured in order to establish the conformation. To determine the stability constants of Sc with EPS and heparin, a Free-ion selective radiotracer extraction (FISRE) method has been used. (3) Results: AF4-MALS showed that radical depolymerization produces monodisperse EPSs, suitable for therapeutic use. EPS conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration. The LogK of Sc-EPS complexes have been determined and showing that they are comparable to the Sc-Hep. (4) Conclusions: EPSs are very promising to be coupled with the theranostic pair of scandium for Nuclear Medicine.


Assuntos
Alteromonas/química , Complexos de Coordenação/química , Polissacarídeos/química , Escândio/química , Configuração de Carboidratos , Fracionamento por Campo e Fluxo , Hidrodinâmica , Luz , Medicina Nuclear , Concentração Osmolar , Espalhamento de Radiação , Nanomedicina Teranóstica , Viscosidade
10.
Food Chem ; 353: 129460, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33725543

RESUMO

Endo-fucoidanases are important in structural analysis of fucoidans and preparation of fuco-oligosaccharides. However their enzymological properties and analysis of degradation products are scarcely investigated. Truncated endo-α (1 â†’ 3)-fucoidanase Fda1 (tFda1B from Alteromonas sp. was overexpressed and characterized, showing highest activity at pH 7.0, 35 °C, and 1.0 M NaCl. Its Km and kcat were 3.88 ± 0.81 mg/mL and 0.82 ± 0.17 min-1. Fe3+ and Mn2+ enhanced activity by 100% and 19.5% respectively. Co2+ and Cu2+ completely inactivated tFda1B, whereas Ni2+, Mg2+, Zn2+, Pb2+, Ca2+, Ba2+ and Li+ decreased activity by 58.8%, 56.0%, 50.6%, 47.7%, 28.9%, 15.6% and 37.5%, respectively. Catalytic residues were identified through structure and sequence alignment, and confirmed by mutagenesis. Degradation products of Kjellmaniella crassifolia fucoidan by tFda1B were characterized by LC-ESI-MS/MS, confirming tFda1B belongs to endo-(1 â†’ 3)-fucoidanases, and backbone of K. crassifolia fucoidan is 1 â†’ 3 fucoside linkage. This endo-α (1 â†’ 3)-fucoidanase would be useful for elucidating fucoidan structures, and be used as a food enzyme.


Assuntos
Alteromonas/enzimologia , Hidrolases/química , Hidrolases/metabolismo , Polissacarídeos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Estabilidade Enzimática , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Concentração de Íons de Hidrogênio , Hidrolases/genética , Mutagênese Sítio-Dirigida , Oligossacarídeos/química , Feófitas/química , Feófitas/metabolismo , Filogenia , Polissacarídeos/química , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Especificidade por Substrato , Espectrometria de Massas em Tandem
11.
Appl Microbiol Biotechnol ; 105(1): 389-400, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33191461

RESUMO

Indiscriminate use of organophosphorus (OP)-based insecticides is a great concern to human health because of bioaccumulation-induced health hazards. Potentially fatal consequences and limited treatment methods of OP poisoning necessitate the need for the development of reliable, selective, cost-effective, and sensitive methods of OP detection. To tackle this issue, the development of effective devices and methods is required to sensitively detect as well as degrade OPs. Enzymatic sensor systems have gained popularity due to high catalytic activity, enhanced detection limits, and high sensitivity with the environmentally benign operation. Organophosphorus acid anhydrolase (OPAA) from Alteromonas sp. JD6.5 is capable of hydrolyzing the P-F, P-O, P-S, and P-CN bonds, in OPs, including nerve agents of the G/V-series. Several mutants of OPAA are reported which have greater activity against various OPs. In this study, recombinant expression of the OPAA-FL variant in Escherichia coli was performed, purified, and subsequently tested for activity against ethyl paraoxon. OPAA-FL variant showed its optimum activity at pH 8.5 and 50 °C. Colorimetric and fluorometric assays were used for estimation of ethyl paraoxon based on p-nitrophenol and fluorescein isothiocyanate (FITC) fluorescence intensity, respectively. Colorimetric and fluorometric assay estimation indicates that ethyl paraoxon can be estimated in the linear range of 0.01 to 1 mM and 0.1 to 0.5 mM, with LOD values 0.04 mM and 0.056 mM, respectively. Furthermore, the OPAA-FL variant was immobilized into alginate microspheres for colorimetric detection of ethyl paraoxon and displayed a linear range of 0.025 to 1 mM with a LOD value of 0.06 mM. KEY POINTS: • Biosensing of paraoxon with purified and encapsulated OPAA-FL variant. • Colorimetric and fluorometric biosensing assay developed using OPAA-FL variant for paraoxon. • First report on alginate encapsulation of OPAA-FL variant for biosensing of paraoxon. Graphical abstract.


Assuntos
Alteromonas , Técnicas Biossensoriais , Praguicidas , Arildialquilfosfatase/genética , Colorimetria , Compostos Organofosforados , Paraoxon , Praguicidas/análise
12.
Mar Genomics ; 55: 100804, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32665084

RESUMO

The whole genome of Alteromonas pelagimontana 5.12T, a psychrotolerant deep-sea bacterium isolated from the sediment sample of eastern Southwest Indian Ridge, was sequenced and analysed for understanding its metabolic capacities and biosynthesis potential of natural products. The circular genome contained 4.3 Mb with a GC content of 42.6 mol%. Genomic data mining revealed a gene cluster for heavy metal resistance (czcABC, acrB, arsR1, copA, nikA, mntH, mntP), exopolysaccharides (EPS; epsCDEFHLM) and polyhydroxyalkanoates (PHA; phbC) production, as well as genes involved in complex polysaccharide degradation. Genes that could allow strain 5.12T to cope with acid stress (ibaG) and heat shock (ibpA, hslR) were observed along with ten chaperone-encoding genes which could possibly play vital role in adaptability of this strain to the hydrothermally influenced environment. Gene clusters for secondary metabolite production such as bacteriocin and arylpolyene were also predicted. Thus, genome sequencing and data mining provided insights into the molecular mechanisms involved in the adaptation to hydrothermally influenced deep-sea environment that could promote further experimental exploration.


Assuntos
Alteromonas/genética , Genoma Bacteriano , Sedimentos Geológicos/microbiologia , Fontes Hidrotermais/microbiologia , Oceano Índico , Polissacarídeos/metabolismo , Sequenciamento Completo do Genoma
13.
Int J Syst Evol Microbiol ; 70(12): 6396-6401, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33156994

RESUMO

A Gram-stain-negative, aerobic, non-spore-forming, non-motile and ovoid or rod-shaped bacterial strain, MYP5T, was isolated from seawater in Jeju island of South Korea. MYP5T grew optimally at 30-35 °C and in the presence of 2.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that MYP5T fell within the clade enclosed by the type strains of species of the genus Alteromonas, clustering with the type strains of Alteromonas confluentis and Alteromonas halophila. MYP5T exhibited the highest 16S rRNA gene sequence similarity value (98.0 %) to the type strain of A. confluentis and similarities of 95.1-97.9 % to the type strains of the other species of the genus Alteromonas. ANI and dDDH values of genomic sequences between MYP5T and the type strains of 22 species of the genus Alteromonas were 66.8-70.5 % and 18.6-27.5 %, respectively. The DNA G+C content of MYP5T, determined from the genome sequence, was 46.1 %. MYP5T contained Q-8 as the predominant ubiquinone and C18 : 1 ω7c, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and 10-methyl C17 : 0 as the major fatty acids. The major polar lipids of MYP5T were phosphatidylethanolamine and phosphatidylglycerol. Distinguishing phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that MYP5T is separated from species of the genus Alteromonas. On the basis of the data presented, MYP5T is considered to represent a novel species of the genus Alteromonas, for which the name Alteromonas ponticola sp. nov. is proposed. The type strain is MYP5T (=KCTC 82144T=NBRC 114354T).


Assuntos
Alteromonas/classificação , Filogenia , Água do Mar/microbiologia , Alteromonas/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfatidiletanolaminas/química , Fosfatidilgliceróis/química , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA
14.
Mar Drugs ; 18(9)2020 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-32867255

RESUMO

Two Alteromonas sp. strains isolated from deep seawater were grown to promote the production of exopolysaccharides (EPS, E611 and E805), which were incorporated into chitosan solutions to develop films. The combination of the major marine polysaccharides (chitosan and the isolated bacterial EPS) resulted in the formation of homogenous, transparent, colorless films, suggesting good compatibility between the two components of the film-forming formulation. With regards to optical properties, the films showed low values of gloss, in the range of 5-10 GU, indicating the formation of non-glossy and rough surfaces. In addition to the film surface, both showed hydrophobic character, with water contact angles higher than 100 º, regardless of EPS addition. Among the two EPS under analysis, chitosan films with E805 showed better mechanical performance, leading to resistant, flexible, easy to handle films.


Assuntos
Alteromonas/metabolismo , Quitosana/química , Polissacarídeos Bacterianos/química , Cor , Composição de Medicamentos , Interações Hidrofóbicas e Hidrofílicas , Polissacarídeos Bacterianos/isolamento & purificação , Água do Mar/microbiologia , Propriedades de Superfície , Resistência à Tração , Microbiologia da Água
15.
J Nat Prod ; 83(9): 2696-2705, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32869646

RESUMO

Co-cultivation has been used as a promising tool to turn on or up-regulate cryptic biosynthetic pathways for microbial natural product discovery. Recently, a modified culturing strategy similar to co-cultivation was investigated, where heat-killed inducer cultures were supplemented to the culture medium of producer fermentations to induce cryptic pathways. In the present study, the repeatability and effectiveness of both methods in turning on cryptic biosynthetic pathways were unbiasedly assessed using UHPLC-HRESIMS-based metabolomics analysis. Both induction methods had good repeatability, and they resulted in very different induced metabolites from the tested producers. Co-cultivation generated more induced mass features than the heat-killed inducer cultures, while both methods resulted in the induction of mass features not observed using the other induction method. As examples, pathways leading to two new natural products, N-carbamoyl-2-hydroxy-3-methoxybenzamide (1) and carbazoquinocin G (5), were induced and up-regulated through co-culturing a producer Streptomyces sp. RKND-216 with inducers Alteromonas sp. RKMC-009 and M. smegmatis ATCC 120515, respectively.


Assuntos
Redes e Vias Metabólicas , Metaboloma , Alteromonas/metabolismo , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Produtos Biológicos , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Técnicas de Cocultura , Descoberta de Drogas , Temperatura Alta , Humanos , Testes de Sensibilidade Microbiana , Mycobacterium smegmatis/efeitos dos fármacos , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray , Esterilização , Streptomyces/metabolismo
16.
mBio ; 11(4)2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32788385

RESUMO

Many microorganisms produce resting cells with very low metabolic activity that allow them to survive phases of prolonged nutrient or energy stress. In cyanobacteria and some eukaryotic phytoplankton, the production of resting stages is accompanied by a loss of photosynthetic pigments, a process termed chlorosis. Here, we show that a chlorosis-like process occurs under multiple stress conditions in axenic laboratory cultures of Prochlorococcus, the dominant phytoplankton linage in large regions of the oligotrophic ocean and a global key player in ocean biogeochemical cycles. In Prochlorococcus strain MIT9313, chlorotic cells show reduced metabolic activity, measured as C and N uptake by Nanoscale secondary ion mass spectrometry (NanoSIMS). However, unlike many other cyanobacteria, chlorotic Prochlorococcus cells are not viable and do not regrow under axenic conditions when transferred to new media. Nevertheless, cocultures with a heterotrophic bacterium, Alteromonas macleodii HOT1A3, allowed Prochlorococcus to survive nutrient starvation for months. We propose that reliance on co-occurring heterotrophic bacteria, rather than the ability to survive extended starvation as resting cells, underlies the ecological success of Prochlorococcus IMPORTANCE The ability of microorganisms to withstand long periods of nutrient starvation is key to their survival and success under highly fluctuating conditions that are common in nature. Therefore, one would expect this trait to be prevalent among organisms in the nutrient-poor open ocean. Here, we show that this is not the case for Prochlorococcus, a globally abundant and ecologically important marine cyanobacterium. Instead, Prochlorococcus relies on co-occurring heterotrophic bacteria to survive extended phases of nutrient and light starvation. Our results highlight the power of microbial interactions to drive major biogeochemical cycles in the ocean and elsewhere with consequences at the global scale.


Assuntos
Anemia Hipocrômica , Interações Microbianas , Nutrientes , Prochlorococcus/metabolismo , Alteromonas/metabolismo , Cultura Axênica , Genoma Bacteriano , Processos Heterotróficos , Viabilidade Microbiana , Filogenia , Prochlorococcus/crescimento & desenvolvimento , Água do Mar/microbiologia
17.
Int J Syst Evol Microbiol ; 70(8): 4531-4536, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32614764

RESUMO

A Gram-staining-negative bacterium, designated 345S023T, was isolated from a sea water sample from the Indian Ocean. The results of 16S rRNA gene sequence analysis revealed that 345S023T represents a member of the genus Alteromonas, with closely related type strains Alteromonas fortis 1T (98.7 %), Alteromonas hispanica F-32T (98.6 %) and Alteromonas genovensis LMG 24078T (98.6 %). Up-to-date bacterial core gene set analysis revealed that 345S023T formed a phyletic lineage with Alteromonas australica H 17T. The case for 345S023T representing a novel species was supported by genomic results. Pairwise in silico DNA-DNA hybridization and average nucleotide identity values were much lower than the proposed and generally accepted species boundaries. Strain 345S023T contains ubiquinone-8 (Q-8) as the sole isoprenoid quinone, summed featured 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω7c as the dominant cellular fatty acids (>10 %), and phosphatidylglycerol and phosphatidylethanolamine as the major polar lipids. The genome of strain 345S023T consisted of a 4.4 Mb chromosome with a DNA G+C content of 44.4 %. On the basis of these genomic, chemotaxonomic and phenotypic characteristics, we propose a novel species: Alteromonas profundi sp. nov. The type strain is 345S023T(=JCM 33893T=MCCC 1K04570T).


Assuntos
Alteromonas/classificação , Filogenia , Água do Mar/microbiologia , Alteromonas/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Oceano Índico , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
18.
Curr Microbiol ; 77(10): 2813-2820, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32588135

RESUMO

Although Alteromonas is ubiquitous in the marine environment, very little is known about Alteromonas phages, with only ten, thus far, being isolated and reported on. In this study, a novel double-stranded DNA phage, Alteromonas phage P24, which infects Alteromonas macleodii, was isolated from the coastal waters off Qingdao. Alteromonas phage P24 has a siphoviral morphology, with an icosahedral head, 61 ± 1 nm in diameter, and a tail length of 105 ± 1 nm. Alteromonas phage P24 contains lipids. It has an optimal temperature and pH for growth of 20℃ and 5-7, respectively. A one-step growth curve shows a latent period of 55 min, a rise period of 65 min, and an average burst size of approximately 147 virions per cell. Alteromonas phage P24 has the genome of 46,945 bp with 43.80% GC content and 74 open reading frames (ORFs) without tRNA. The results of the phylogenetic tree, based on the mcp and terL genes, show that Alteromonas phage P24 is closely related to Aeromonas phage phiARM81ld. Meanwhile, phylogenetic analysis based on the whole genome of P24 indicates that it forms a unique viral sub-cluster within Siphoviridae. This study contributes to the understanding of the genomic characteristics and the virus-host interactions of Alteromonas phages.


Assuntos
Alteromonas , Bacteriófagos , Genoma Viral , Siphoviridae , Alteromonas/virologia , Bacteriófagos/classificação , Bacteriófagos/genética , DNA Viral/genética , Genoma Viral/genética , Fases de Leitura Aberta , Filogenia , Siphoviridae/classificação , Siphoviridae/genética
19.
Biofouling ; 36(5): 505-515, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32545993

RESUMO

Biofouling control in reverse osmosis membranes (ROMs) is challenging due to the high cost of treatments, and reduction in the life of ROMs. This study characterizes the biofouling in the ROMs from a desalination plant and reports its effective removal using the supernatant obtained from Alteromonas sp. strain Ni1-LEM. The characterization of the bacterial community revealed that the most abundant taxa in ROMs were the genera Fulvivirga and Pseudoalteromonas, and unclassified species of the families Flavobacteriaceae and Sphingomonadaceae. This bacterial community significantly decreased upon treatment with the supernatant from Alteromonas sp. Ni1-LEM, resulting in the prevalence of the genus Pseudoalteromonas. Furthermore, this bacterial supernatant significantly inhibited cell adhesion of seven benthic microalgae isolated from ROMs as well as promoting cell detachment of the existing microbial biofilms. The study showed that the extracellular supernatant modified the conformation of extracellular polymeric substances (EPS) in the biofouling of ROMs without any biocidal effects.


Assuntos
Alteromonas , Incrustação Biológica , Purificação da Água , Biofilmes , Chile , Humanos , Membranas , Membranas Artificiais , Osmose , Plantas
20.
Mar Drugs ; 18(6)2020 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-32545859

RESUMO

As prebiotics, galacto-oligosaccharides (GOSs) can improve the intestinal flora and have important applications in medicine. ß-galactosidases could promote the synthesis of GOSs in lactose and catalyze the hydrolysis of lactose. In this study, a new ß-galactosidase gene (gal2A), which belongs to the glycoside hydrolase family 2, was cloned from marine bacterium Alteromonas sp. QD01 and expressed in Escherichia coli. The molecular weight of Gal2A was 117.07 kDa. The optimal pH and temperature of Gal2A were 8.0 and 40 °C, respectively. At the same time, Gal2A showed wide pH stability in the pH range of 6.0-9.5, which is suitable for lactose hydrolysis in milk. Most metal ions promoted the activity of Gal2A, especially Mn2+ and Mg2+. Importantly, Gal2A exhibited high transglycosylation activity, which can catalyze the formation of GOS from milk and lactose. These characteristics indicated that Gal2A may be ideal for producing GOSs and lactose-reducing dairy products.


Assuntos
Alteromonas/química , Lactose/química , Leite , Prebióticos , beta-Galactosidase/química , Alteromonas/genética , Animais , Clonagem Molecular , Indústria de Laticínios , Oligossacarídeos/química , beta-Galactosidase/genética
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