Showing papers in "Canadian Journal of Microbiology in 2011"
TL;DR: In this article, 25 strains of plant growth-promoting rhizobacteria (PGPR) containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase and 10 strains of rhizobia were isolated from rhizosphere soil sample.
Abstract: Twenty-five strains of plant-growth-promoting rhizobacteria (PGPR) containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase and 10 strains of rhizobia were isolated from rhizosphere soil sample...
224 citations
TL;DR: Direct comparisons of 16S rRNA gene sequence data highlighted significant differences between the bacterial communities of each layer, with the greatest differences occurring within Actinobacteria.
Abstract: The abundance and structure of archaeal and bacterial communities from the active layer and the associated per- mafrost of a moderately acidic (pH < 5.0) High Arctic wetland (Axel Heiberg Island, Nunavut, Canada) were investigated using culture- and molecular-based methods. Aerobic viable cell counts from the active layer were ∼100-fold greater than those from the permafrost (2.5 × 10 5 CFU·(g soil dry mass) -1 ); however, a greater diversity of isolates were cultured from permafrost, as determined by 16S rRNA gene sequencing. Isolates from both layers demonstrated growth characteristics of a psychrotolerant, halotolerant, and acidotolerant community. Archaea constituted 0.1% of the total 16S rRNA gene copy number and, in the 16S rRNA gene clone library, predominantly (71% and 95%) consisted of Crenarchaeota related to Group I. 1b. In contrast, bacterial communities were diverse (Shannon's diversity index, H = ∼4), with Acidobacteria con- stituting the largest division of active layer clones (30%) and Actinobacteria most abundant in permafrost (28%). Direct comparisons of 16S rRNA gene sequence data highlighted significant differences between the bacterial communities of each layer, with the greatest differences occurring within Actinobacteria. Comparisons of 16S rRNA gene sequences with those from other Arctic permafrost and cold-temperature wetlands revealed commonly occurring taxa within the phyla Chloroflexi, Acidobacteria, and Actinobacteria (families Intrasporangiaceae and Rubrobacteraceae).
145 citations
TL;DR: Antifungal activity of curcumin might be originating from alteration of membrane-associated properties of ATPase activity, ergosterol biosynthesis, and proteinase secretion.
Abstract: Curcumin, an important Asian spice, is part of many Indian food preparations. This work evaluates the antifungal activity of curcumin against 14 strains of Candida (10 clinical and 4 standard). Cur...
116 citations
TL;DR: Comparing the effectiveness of four commercial soil DNA extraction kits to extract pure, high-quality bacterial and eukaryotic DNA from PAH-contaminated soils found that the FastDNA SPIN kit provided significantly higher DNA yields for all soils; however, it also resulted in the highest levels of humic acid contamination.
Abstract: Molecular characterization of the microbial populations of soils and sediments contaminated with polycyclic aromatic hydrocarbons (PAHs) is often a first step in assessing intrinsic biodegradation potential. However, soils are problematic for molec- ular analysis owing to the presence of organic matter, such as humic acids. Furthermore, the presence of contaminants, such as PAHs, can cause further challenges to DNA extraction, quantification, and amplification. The goal of our study was to compare the effectiveness of four commercial soil DNA extraction kits (UltraClean Soil DNA Isolation kit, PowerSoil DNA Isolation kit, PowerMax Soil DNA Isolation kit, and FastDNA SPIN kit) to extract pure, high-quality bacterial and eukaryotic DNA from PAH- contaminated soils. Six different contaminated soils were used to determine if there were any biases among the kits due to soil properties or level of contamination. Extracted DNAwas used as a template for bacterial 16S rDNA and eukaryotic 18S rDNA am- plifications, and PCR products were subsequently analyzed using denaturing gel gradient electrophoresis (DGGE). We found that the FastDNA SPIN kit provided significantly higher DNAyields for all soils; however, it also resulted in the highest levels of hu- mic acid contamination. Soil texture and organic carbon content of the soil did not affect the DNAyield of any kit. Moreover, a liquid-liquid extraction of the DNA extracts found no residual PAHs, indicating that all kits were effective at removing contami- nants in the extraction process. Although the PowerSoil DNA Isolation kit gave relatively low DNAyields, it provided the highest quality DNA based on successful amplification of both bacterial and eukaryotic DNA for all six soils. DGGE fingerprints among the kits were dramatically different for both bacterial and eukaryotic DNA. The PowerSoil DNA Isolation kit revealed multiple bands for each soil and provided the most consistent DGGE profiles among replicates for both bacterial and eukaryotic DNA.
76 citations
TL;DR: The nature and role of toxic arsenic in bacterial systems is highlighted and the various genes responsible for this heavy-metal resistance in nature and the mechanisms to detoxify this element are discussed.
Abstract: Contamination of the environment with heavy metals has increased drastically over the last few decades. The heavy metals that are toxic include mercury, cadmium, arsenic, and selenium. Of these heavy metals, arsenic is one of the most important global environmental pollutants and is a persistent bioaccumulative carcinogen. It is a toxic metalloid that exists in two major inorganic forms: arsenate and arsenite. Arsenite disrupts enzymatic functions in cells, while arsenate behaves as a phosphate analog and interferes with phosphate uptake and utilization. Despite its toxicity, arsenic may be actively sequestered in plant and animal tissues. Various microbes interact with this metal and have shown resistance to arsenic exposure, and they appear to possess the ars operon for arsenic resistance consisting of three to five genes, i.e., arsRBC or arsRDABC, organized into a single transcriptional unit; some microbes even use it for respiration. Microbial interactions with metals may have several implications for the environment. Microbes may play a role in cycling of toxic heavy metals and in remediation of metal-contaminated sites. There is a correlation between tolerance to heavy metals and antibiotic resistance, a global problem currently threatening the treatment of infections in plants, animals, and humans. The purpose of this review is to highlight the nature and role of toxic arsenic in bacterial systems and to discuss the various genes responsible for this heavy-metal resistance in nature and the mechanisms to detoxify this element.
75 citations
TL;DR: It appears that some of the Gram-negative bacteria identified should now be regarded as potentially useful in some cheese technologies, and the assessment of their positive versus negative role should be objectively examined.
Abstract: The surface microflora (902 isolates) of Livarot cheeses from three dairies was investigated during ripening. Yeasts were mainly identified by Fourier transform infrared spectroscopy. Geotrichum candidum was the dominating yeast among 10 species. Bacteria were identified using Biotype 100 strips, dereplicated by repetitive extragenic palindromic PCR (rep-PCR); 156 representative strains were identified by either BOX-PCR or (GTG)5-PCR, and when appropriate by 16S rDNA sequencing and SDS-PAGE analysis. Gram-positive bacteria accounted for 65% of the isolates and were mainly as- signed to the genera Arthrobacter, Brevibacterium, Corynebacterium, and Staphylococcus. New taxa related to the genera Agrococcus and Leucobacter were found. Yeast and Gram-positive bacteria strains deliberately added as smearing agents were sometimes undetected during ripening. Thirty-two percent of the isolates were Gram-negative bacteria, which showed a high level of diversity and mainly included members of the genera Alcaligenes, Hafnia, Proteus, Pseudomonas, and Psy- chrobacter. Whatever the milk used (pasteurized or unpasteurized), similar levels of biodiversity were observed in the three dairies, all of which had efficient cleaning procedures and good manufacturing practices. It appears that some of the Gram- negative bacteria identified should now be regarded as potentially useful in some cheese technologies. The assessment of their positive versus negative role should be objectively examined.
71 citations
TL;DR: Les streptocoques buccaux englobent a la fois des bacteries inoffensives et dangereuses des pathogenes opportunistes initiateur of maladies and de dommages chez l’hote.
Abstract: La flore microbienne buccale humaine constitue un biofilm tres diversifie. Vingt-cinq especes de streptocoques buccaux resident dans la cavite buccale humaine et representent a peu pres 20 % du total des bacteries buccales. La taxonomie de ces bacteries est complexe et reste provisoire. Les streptocoques buccaux englobent a la fois des bacteries inoffensives et dangereuses. Chaque espece a developpe des proprietes specifiques pour coloniser les differents sites buccaux soumis a de constants changements de conditions, pour combattre les competiteurs et pour resister aux agressions externes (systeme immunitaire de l’hote, chocs physico-chimiques, frictions mecaniques). Les desequilibres dans la flore indigene sont la cause de maladies buccales et sous des conditions propices, des streptocoques commensaux peuvent devenir des pathogenes opportunistes initiateur de maladies et de dommages chez l’hote. Le groupe des « streptocoques mutans » inclu les principales bacteries impliquees dans la formation de la cari...
67 citations
TL;DR: It is suggested that the success of treatment interventions for chronic CF lung disease will rely on the context of the microbes within microbial communities, and the microbiology of CF airways may serve as a model to investigate the emergent properties of other clinically relevant microbial communities in the human body.
Abstract: Microbial communities characterize the airways of cystic fibrosis (CF) patients. Members of these diverse and dynamic communities can be thought of as pathogens, benign commensals, or synergens--organisms not considered pathogens in the traditional sense but with the capacity to alter the pathogenesis of the community through microbe-microbe or polymicrobe-host interactions. Very few bacterial pathogens have been implicated as clinically relevant in CF; however, the CF airway microbiome can be a reservoir of previously unrecognized but clinically relevant organisms. A combination of culture-dependent and culture-independent approaches provides a more comprehensive perspective of CF microbiology than either approach alone. Here we review these concepts, highlight the future challenges for CF microbiology, and discuss the implications for the management of CF airway infections. We suggest that the success of treatment interventions for chronic CF lung disease will rely on the context of the microbes within microbial communities. The microbiology of CF airways may serve as a model to investigate the emergent properties of other clinically relevant microbial communities in the human body.
64 citations
TL;DR: It is demonstrated that the SYBR Green I method is useful for describing new species and as a screening tool to quickly identify the relatedness of uncharacterized isolates with similar 16S rRNA gene sequences.
Abstract: Standardized procedures must be followed when characterizing, officially describing, and validly naming novel bacteria. For species descriptions, DNA–DNA hybridization still is needed for whole-gen...
61 citations
TL;DR: It is demonstrated that one of these enzymes is involved in the degradation of lignin, one of the most important processes in catabolic processes that have a wide variety of applications.
Abstract: Rhodococcus is a genus of mycolic-acid-containing actinomycetes that utilize a remarkable variety of organic compounds as growth substrates. This degradation helps maintain the global carbon cycle and has increasing applications ranging from the biodegradation of pollutants to the biocatalytic production of drugs and hormones. We have been using Rhodococcus jostii RHA1 as a model organism to understand the catabolic versatility of Rhodococcus and related bacteria. Our approach is exemplified by the discovery of a cluster of genes specifying the catabolism of cholesterol. This degradation proceeds via β-oxidative degradation of the side chain and O2-dependent cleavage of steroid ring A in a process similar to bacterial degradation of aromatic compounds. The pathway is widespread in Actinobacteria and is critical to the pathogenesis of Mycobacterium tuberculosis, arguably the world's most successful pathogen. The close similarity of some of these enzymes with biphenyl- and polychlorinated-biphenyl-degrading enzymes that we have characterized is facilitating inhibitor design. Our studies in RHA1 have also provided important insights into a number of novel metalloenzymes and their biosynthesis, such as acetonitrile hydratase (ANHase), a cobalt-containing enzyme with no significant sequence identity with characterized nitrile hydratases. Molecular genetic and biochemical studies have identified AnhE as a dimeric metallochaperone that delivers cobalt to ANHase, enabling its maturation in vivo. Other metalloenzymes we are characterizing include N-acetylmuramic acid hydroxylase, which catalyzes an unusual hydroxylation of the rhodococcal and mycobacterial peptidoglycan, and 2 RHA1 dye-decolorizing peroxidases. Using molecular genetic and biochemical approaches, we have demonstrated that one of these enzymes is involved in the degradation of lignin. Overall, our studies are providing fundamental insights into a range of catabolic processes that have a wide variety of applications.
60 citations
TL;DR: The overall conclusion is that α-mangostin is a multitarget inhibitor of mutans streptococci and may be useful as an anticaries agent.
Abstract: The increasing prevalence of dental caries is making it more of a major world health problem. Caries is the direct result of acid production by cariogenic oral bacteria, especially Streptococcus mutans. New and better antimicrobial agents active against cariogenic bacteria are badly needed, especially natural agents derived directly from plants. We have evaluated the inhibitory actions of α-mangostin, a xanthone purified from ethanolic extracts of the tropical plant Garcinia mangostana L., by repeated silica gel chromatography. α-Mangostin was found to be a potent inhibitor of acid production by S. mutans UA159, active against membrane enzymes, including the F(H+)-ATPase and the phosphoenolpyruvate – sugar phosphotransferase system. α-Mangostin also inhibited the glycolytic enzymes aldolase, glyceraldehyde-3-phosphate dehydrogenase, and lactic dehydrogenase. Glycolysis by intact cells in suspensions or biofilms was inhibited by α-mangostin at concentrations of 12 and 120 µmol·L–1, respectively, in a pH-de...
TL;DR: Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors, and the sensitivity of these assemblage made them interesting indicators of climate change.
Abstract: Microbial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25°C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0-3 cm and 3-6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities.
TL;DR: The results indicate that SYBR, in addition to being used as a component of LIVE/DEAD stain, may also be use as a probe to evaluate the physiological state of S. epidermidis cells.
Abstract: Staphylococcus epidermidis biofilms with different proportions of viable but nonculturable bacteria were used to show that SYBR green (SYBR) may be used as a probe to evaluate the bacterial physiol...
TL;DR: It is demonstrated that prebiotics with linear chains consisting of galactose units are better utilized by probiotics than are those consisting of glucose and fructose units, and the ability of probiotic bacteria to utilize prebiotic bacteria is strain-specific.
Abstract: A better understanding of the functionality of probiotics and dietary fibres with prebiotic activity is required for the development of improved synbiotic preparations. In this study, utilization o...
TL;DR: The results clearly show the antigiardial effect of the probiotic in vivo by modulating the gut cells to inhibit the colonization and multiplication of Giardia trophozoites, thus reducing the severity and duration of murine giardiasis.
Abstract: The study describes the in vivo activity of Lactobacillus casei in malnourished Giardia lamblia-infected BALB/c mice. By experimentation, it was found that daily administration of the probiotic 7 days before inoculation with Giardia trophozoites in malnourished mice efficiently reduced both the severity and duration of giardiasis. More specifically, excretion of Giardia cysts and trophozoites counts were reduced, while faecal lactobacilli counts increased significantly in probiotic-fed malnourished mice, compared with control mice. Interestingly, it was also observed that oral feeding of the probiotic to malnourished mice abrogated all the anthropometric and biochemical anomalies. Histologically, morphological and cellular alteration of microvillus membrane integrity revealed that probiotic administration ameliorated the mucosal damage in malnourished, probiotic-inoculated, Giardia-infected mice compared with the severe microvillus atrophy, œdematous and vacuolated epithelial cells, and ileitis in malnourished Giardia-infected mice. The results clearly show the antigiardial effect of the probiotic in vivo by modulating the gut cells to inhibit the colonization and multiplication of Giardia trophozoites, thus reducing the severity and duration of murine giardiasis.
TL;DR: The authors' data show that Cronobacter species harbor different virulence traits, and three putative virulence genes were identified primarily in C. sakazakii, including the sip gene, which was the most frequently detected.
Abstract: Cronobacter spp. (Enterobacter sakazakii) includes gram-negative opportunistic foodborne pathogens known as rare but important causes of life-threatening neonatal infections. However, the pathogenic mechanism is not yet clear. In this study, 43 isolates of Cronobacter, from human and nonhuman sources, were analyzed. A total of four clusters were identified and 32 DNA pulsotypes were observed by pulsed-field gel electrophoresis. In addition, 86% of the Cronobacter isolates were able to adhere to HEp-2 cells and 35% were invasive, Cronobacter sakazakii isolates being the most efficient. Twenty-six percent of Cronobacter isolates were able to form biofilms, mainly those from nonhuman sources, such as Cronobacter dublinensis and Cronobacter malonaticus. Three putative virulence genes (siderophore-interacting protein (sip), type III hemolysin (hly), and plasminogen activator (cpa)) were identified by bioinformatic analysis and then detected by PCR. The sip gene was the most frequently detected (60%; 26/43), fo...
TL;DR: Canonical correspondence analysis demonstrated that total phosphorus and water temperature were the dominant environmental factors affecting bacterial community composition in the sediment.
Abstract: Bacterial community structure and the effects of several environmental factors on bacterial community distribution were investigated in the sediment of the macrophyte-dominated and algae-dominated ...
TL;DR: The first group of single-stranded DNA aptamers that are highly specific to enterotoxigenic Escherichia coli (ETEC) K88 was obtained from an enriched oligonucleotide pool by the SELEX procedure, during which the K88 fimbriae protein was used as the target and bovine serum albumin as counter targets.
Abstract: In this study, the first group of single-stranded DNA aptamers that are highly specific to enterotoxigenic Escherichia coli (ETEC) K88 was obtained from an enriched oligonucleotide pool by the SELE...
TL;DR: The wide host ranges of these phages suggested they could be used for simultaneous biocontrol of some Salmonella serotypes and E. coli O157:H7, which lysed at least 70% of the 234 strains tested.
Abstract: Four phages isolated from cattle and poultry feces were analyzed for their ability to lyse Salmonella serotypes and Escherichia coli O157:H7. The phage one-step growth curves, morphology, and genet...
TL;DR: Data support hypotheses that a relationship exists between the mycorrhizal status of Cyperaceae and their habitat, and that AM have a positive role in plant tolerance to ultramafic soils (mineral nutrition and metal tolerance), and suggest the use of these pioneer plants with AM management as potential tools for nickel mine site rehabilitation in New Caledonia.
Abstract: In New Caledonia, a hot spot of biodiversity, plants from the Cyperaceae family are mostly endemic and considered pioneers of the nickel-rich natural serpentine ecosystem. The aim of the study was ...
TL;DR: Enterococcus faecium MC13 could be used as potential fish probiotic against pathogens such as V. parahaemolyticus, Vibrio harveyi, and Aeromonas hydrophila in fisheries and could be a valuable seafood biopreservative against L. monocytogenes.
Abstract: A bacteriocin producer strain MC13 was isolated from the gut of Mugil cephalus (grey mullet) and identified as Enterococcus faecium. The bacteriocin of E. faecium MC13 was purified to homogeneity, ...
TL;DR: Application of pyocyanin-producing pseudomonads together with rhizobia contributes to the enhancement of nodulation ability and better sustains the growth and productivity of groundnut even in the presence of M. phaseolina.
Abstract: The purified pyocyanin from Pseudomonas aeruginosa TO3 was investigated for its antagonistic activity against Macrophomina phaseolina and as a signaling molecule for development of biofilm by rhizobial strain Ca2. The antagonistic activity of purified pyocyanin, as determined by a dry mass method, showed inhibition of M. phaseolina. Biofilm formation by strain Ca2 was performed by crystal violet assay. There was an increase in biofilm development by Ca2 with an increase in pyocyanin concentration up to 0.12 nmol·L–1, followed by a reduction. Using a well-diffusion method, we determined the effect of pyocyanin on disease suppression and biofilm formation by strain Ca2 on radicles of groundnut (Arachis hypogaea L.) placed in three concentric whorls on water agar plates. Pyocyanin suppressed disease better at high concentration; however, at lower concentrations increased colony-forming units of Ca2 on radicles of seedlings was observed. A field study in soil infested with M. phaseolina showed that a coinocul...
TL;DR: The fungus showed great potential as an onsite producer for β-glucosidase activity and was able to degrade cellodextrins with an exo-acting approach and could hydrolyse pretreated bagasse to monomeric sugars when combined with Celluclast 1.5L.
Abstract: b-Glucosidase activity plays an essential role for efficient and complete hydrolysis of lignocellulosic biomass. Di- rect use of fungal fermentation broths can be cost saving relative to using commercial enzymes for production of biofuels and bioproducts. Through a fungal screening program for b-glucosidase activity, strain AP (CBS 127449, Aspergillus sac- charolyticus) showed 10 times greater b-glucosidase activity than the average of all other fungi screened, with Aspergillus niger showing second greatest activity. The potential of a fermentation broth of strain AP was compared with the commer- cial b-glucosidase-containing enzyme preparations Novozym 188 and Cellic CTec. The fermentation broth was found to be a valid substitute for Novozym 188 in cellobiose hydrolysis. The Michaelis-Menten kinetics affinity constant as well as per- formance in cellobiose hydrolysis with regard to product inhibition were found to be the same for Novozym 188 and the broth of strain AP. Compared with Novozym 188, the fermentation broth had higher specific activity (11.3 U/mg total pro- tein compared with 7.5 U/mg total protein) and also increased thermostability, identified by the thermal activity number of 66.8 vs. 63.4 °C for Novozym 188. The significant thermostability of strain AP b-glucosidases was further confirmed when compared with Cellic CTec. The b-glucosidases of strain AP were able to degrade cellodextrins with an exo-acting approach and could hydrolyse pretreated bagasse to monomeric sugars when combined with Celluclast 1.5L. The fungus therefore showed great potential as an onsite producer for b-glucosidase activity.
TL;DR: In this article, B. mojavensis mutants were used in a growth room study to determine the development of stalk lesions, indicative of maize seedling blight, by co-inoculations with a wild-type strain of Fusarium verticillioides and with non-fusaric acid producing mutants of the fungus.
Abstract: Maize (Zea mays L.) is susceptible to infection by Fusarium verticillioides through autoinfection and alloinfec- tion, resulting in diseases and contamination of maize kernels with the fumonisin mycotoxins. Attempts at controlling this fungus are currently being done with biocontrol agents such as bacteria, and this includes bacterial endophytes, such as Ba- cillus mojavensis. In addition to producing fumonisins, which are phytotoxic and mycotoxic, F. verticillioides also produces fusaric acid, which acts both as a phytotoxin and as an antibiotic. The question now is Can B. mojavensis reduce lesion de- velopment in maize during the alloinfection process, simulated by internode injection of the fungus? Mutant strains of B. mo- javensis that tolerate fusaric acid were used in a growth room study to determine the development of stalk lesions, indicative of maize seedling blight, by co-inoculations with a wild-type strain of F. verticillioides and with non-fusaric acid producing mutants of F. verticillioides. Lesions were measured on 14-day-old maize stalks consisting of treatment groups in- oculated with and without mutants and wild-type strains of bacteria and fungi. The results indicate that the fusaric-acid- tolerant B. mojavensis mutant reduced stalk lesions, suggesting an in planta role for this substance as an antibiotic. Further, lesion development occurred in maize infected with F. verticillioides mutants that do not produce fusaric acid, indicating a role for other phytotoxins, such as the fumonisins. Thus, additional pathological components should be examined before strains of B. mojavensis can be identified as being effective as a biocontrol agent, particularly for the control of seedling dis- ease of maize.
TL;DR: NMR data showed that the KS-408-2F alginate lyase cleaved the glycosidic linkages between two mannuronates orMannuronate and guluronate (mannuronate-β(1-4)-guluronate), indicating that theKS-408 alginates lyase is a polyM-specific lyase.
Abstract: An alginate lyase gene of a newly isolated Pseudomonas sp. strain KS-408 was cloned by using PCR with the specific primers designed from homologous nucleotide sequences. A partial protein sequence of KS-408 alginate lyase was homology-modeled on the basis of the crystal structure of A1-III alginate lyase from Sphingomonas sp. strain A1. The proposed 3-D structure of KS-408 alginate lyase shows that Asn-198, His-199, Arg-246, and Tyr-253 residues are conserved for the catalytic active site. The recombinant KS-408-1F (with signal peptide) and KS-408-2F (without signal peptide) alginate lyases with the (His)6 tag consist of 393 (44.5 kDa) and 372 (42.4 kDa) amino acids with isoelectric points of 8.64 and 8.46, respectively. The purified recombinant KS-408 alginate lyase was very stable when it was incubated at 40 °C for 30 min. Alginate oligosaccharides produced by the KS-408-2F alginate lyase were purified on a Bio-Gel P2 column and analyzed by thin-layer chromatography, fast-protein liquid chromatography, ...
TL;DR: The results support the idea that notable bacterial genome chimaerism has occurred en route to the formation of mitochondria.
Abstract: Many studies have sought to determine the origin and evolution of mitochondria. Although the Alphaproteobacteria are thought to be the closest relatives of the mitochondrial progenitor, there is dispute as to what its particular sister group is. Some have argued that mitochondria originated from ancestors of the order Rickettsiales, or more specifically of the Rickettsiaceae family, while others believe that ancestors of the family Rhodospirillaceae are also equally likely the progenitors. To resolve some of these disputes, sequence similarity searches and phylogenetic analyses were performed against mitochondria-related proteins in Saccharomyces cerevisiae. The 86 common matches of 5 Alphaproteobacteria (Rickettsia prowazekii, Rhodospirillum rubrum, Rhodopseudomonas palustris, Rhodobacter sphaeroides, and Ochrobactrum anthropi) to yeast mitochondrial proteins were distributed fairly evenly among the 5 species when sorted by highest identity or score. Moreover, exploratory phylogenetic analyses revealed that among these common matches, 44.19% (38) had branched most closely with O. anthropi, while only 34.88% (30) corresponded with Rickettsia prowazekii. More detailed phylogenetic analyses with additional Alphaproteobacteria and including genes from the mitochondria of Reclinomonas americana found matches of mitochondrial genes to those of members of the Rickettsiaceae, Anaplasmataceae, and Rhodospirillaceae families. The results support the idea that notable bacterial genome chimaerism has occurred en route to the formation of mitochondria.
TL;DR: Experiments reported here indicate the commercial viability of B. subtilis Tu-100 for suppression of S. sclerotiorum on oilseed rape, and polymerase chain reaction and DNA sequence analysis identified ituC and ituD, and bacAB and bACD in the genome of isolate Tu- 100.
Abstract: Sclerotinia sclerotiorum causes serious yield losses in crops in the People’s Republic of China. Two formulations of oilseed rape seed containing the bacterium Bacillus subtilis Tu-100 were evaluat...
TL;DR: Three bacteria, Alcaligenes faecalis, Flavobacterium sp.
Abstract: Three bacteria, Alcaligenes faecalis, Flavobacterium sp., and Providencia vermicola, were isolated from dauer juveniles of Rhabditis blumi. The pathogenic effects of the bacteria against 4th instar...
TL;DR: Under gnotobiotic conditions, wild-type A. tumefaciens D3 was shown to be able to promote plant root elongation, while the acdS and lrpL double mutant strain A. pancreas D3-1 lost that ability and ACC deaminase activity and its regulation were also characterized.
Abstract: Some plant-growth-promoting bacteria encode the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, which breaks down ACC, the direct precursor of ethylene biosynthesis in all higher plan...
TL;DR: An estrogen-degrading bacterial consortium from a swine wastewater biotreatment was enriched in the presence of low concentrations (1 mg/L) of estrone, 17β-estradiol (βE2), and equol (EQO) as sole carbon sources, suggesting that nitrifiers are not involved.
Abstract: An estrogen-degrading bacterial consortium from a swine wastewater biotreatment was enriched in the presence of low concentrations (1 mg/L) of estrone (E1), 17β-estradiol (βE2), and equol (EQO) as ...