Arsenic-resistant proteobacterium from the phyllosphere of arsenic-hyperaccumulating fern (Pteris vittata L.) reduces arsenate to arsenite

2006 ◽  
Vol 52 (7) ◽  
pp. 695-700 ◽  
Author(s):  
Bala Rathinasabapathi ◽  
Suresh Babu Raman ◽  
Gina Kertulis ◽  
Lena Ma

An arsenic-resistant bacterium, AsRB1, was isolated from the fronds of Pteris vittata grown in a site contaminated with copper chromium arsenate. The bacterium exhibited resistance to arsenate, arsenite, and antimony in the culture medium. AsRB1, like Pseudomonas putida, grew on MacConkey and xylose–lactose–desoxycholate agars and utilized citrate but, unlike P. putida, was positive for indole test and negative for oxidase test. A phylogenetic analysis of the 16S rRNA gene showed that AsRB1 is a proteobacterium of the beta subclass, related to Pseudomonas saccharophila and Variovorax paradoxus. Following an exogenous supply of arsenate, most arsenic occurred as arsenite in the medium and the cell extracts, suggesting reduction and extrusion of arsenic as the mechanism for arsenic resistance in AsRB1.Key words: arsenate reduction, arsenic bioremediation, Pseudomonas saccharophila, Variovorax paradoxus, Pteris vittala.

2007 ◽  
Vol 73 (22) ◽  
pp. 7192-7198 ◽  
Author(s):  
Lawrence P. Wackett ◽  
Janice A. Frias ◽  
Jennifer L. Seffernick ◽  
David J. Sukovich ◽  
Stephan M. Cameron

ABSTRACT Vibrio furnissii M1 was recently reported to biosynthesize n-alkanes when grown on biopolymers, sugars, or organic acids (M. O. Park, J. Bacteriol. 187:1426-1429, 2005). In the present study, V. furnissii M1 was subjected to genomic analysis and studied biochemically. The sequence of the 16S rRNA gene and repetitive PCR showed that V. furnissii M1 was not identical to other V. furnissii strains tested, but the level of relatedness was consistent with its assignment as a V. furnissii strain. Pulsed-field gel electrophoresis showed chromosomal bands at approximately 3.2 and 1.8 Mb, similar to other Vibrio strains. Complete genomic DNA from V. furnissii M1 was sequenced with 21-fold coverage. Alkane biosynthetic and degradation genes could not be identified. Moreover, V. furnissii M1 did not produce demonstrable levels of n-alkanes in vivo or in vitro. In vivo experiments were conducted by growing V. furnissii M1 under different conditions, extracting with solvent, and analyzing extracts by gas chromatography-mass spectrometry. A highly sensitive assay was used for in vitro experiments with cell extracts and [14C]hexadecanol. The data are consistent with the present strain being a V. furnissii with properties similar to those previously described but lacking the alkane-producing phenotype. V. furnissii ATCC 35016, also reported to biosynthesize alkanes, was found in the present study not to produce alkanes.


1989 ◽  
Vol 9 (4) ◽  
pp. 1507-1512 ◽  
Author(s):  
H Zhu ◽  
H Conrad-Webb ◽  
X S Liao ◽  
P S Perlman ◽  
R A Butow

All mRNAs of yeast mitochondria are processed at their 3' ends within a conserved dodecamer sequence, 5'-AAUAAUAUUCUU-3'. A dominant nuclear suppressor, SUV3-I, was previously isolated because it suppresses a dodecamer deletion at the 3' end of the var1 gene. We have tested the effects of SUV3-1 on a mutant containing two adjacent transversions within a dodecamer at the 3' end of fit1, a gene located within the 1,143-base-pair intron of the 21S rRNA gene, whose product is a site-specific endonuclease required in crosses for the quantitative transmission of that intron to 21S alleles that lack it. The fit1 dodecamer mutations blocked both intron transmission and dodecamer cleavage, neither of which was suppressed by SUV3-1 when present in heterozygous or homozygous configurations. Unexpectedly, we found that SUV3-1 completely blocked cleavage of the wild-type fit1 dodecamer and, in SUV3-1 homozygous crosses, intron conversion. In addition, SUV3-1 resulted in at least a 40-fold increase in the amount of excised intron accumulated. Genetic analysis showed that these phenotypes resulted from the same mutation. We conclude that cleavage of a wild-type dodecamer sequence at the 3' end of the fit1 gene is essential for fit1 expression.


2020 ◽  
Vol 8 (6) ◽  
pp. 936 ◽  
Author(s):  
Claudia Leoni ◽  
Mariateresa Volpicella ◽  
Bruno Fosso ◽  
Caterina Manzari ◽  
Elisabetta Piancone ◽  
...  

Microorganisms inhabiting saline environments are an interesting ecological model for the study of the adaptation of organisms to extreme living conditions and constitute a precious resource of enzymes and bioproducts for biotechnological applications. We analyzed the microbial communities in nine ponds with increasing salt concentrations (salinity range 4.9–36.0%) of the Saltern of Margherita di Savoia (Italy), the largest thalassohaline saltern in Europe. A deep-metabarcoding NGS procedure addressing separately the V5-V6 and V3-V4 hypervariable regions of the 16S rRNA gene of Bacteria and Archaea, respectively, and a CARD-FISH (catalyzed reporter deposition fluorescence in situ hybridization) analysis allowed us to profile the dynamics of microbial populations at the different salt concentrations. Both the domains were detected throughout the saltern, even if the low relative abundance of Archaea in the three ponds with the lowest salinities prevented the construction of the relative amplicon libraries. The highest cell counts were recorded at 14.5% salinity for Bacteria and at 24.1% salinity for Archaea. While Bacteria showed the greatest number of genera in the first ponds (salinity range 4.9–14.5%), archaeal genera were more numerous in the last ponds of the saltern (salinity 24.1–36.0%). Among prokaryotes, Salinibacter was the genus with the maximum abundance (~49% at 34.6% salinity). Other genera detected at high abundance were the archaeal Haloquadratum (~43% at 36.0% salinity) and Natronomonas (~18% at 13.1% salinity) and the bacterial “Candidatus Aquiluna” (~19% at 14.5% salinity). Interestingly, “Candidatus Aquiluna” had not been identified before in thalassohaline waters.


Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 294
Author(s):  
Yan Zhu ◽  
Pascal Drouin ◽  
Dion Lepp ◽  
Xiu-Zhen Li ◽  
Honghui Zhu ◽  
...  

Zearalenone (ZEA) is a mycotoxin widely occurring in many agricultural commodities. In this study, a purified bacterial isolate, Bacillus sp. S62-W, obtained from one of 104 corn silage samples from various silos located in the United States, exhibited activity to transform the mycotoxin ZEA. A novel microbial transformation product, ZEA-14-phosphate, was detected, purified, and identified by HPLC, LC-MS, and NMR analyses. The isolate has been identified as belonging to the genus Bacillus according to phylogenetic analysis of the 16S rRNA gene and whole genome alignments. The isolate showed high efficacy in transforming ZEA to ZEA-14-phosphate (100% transformation within 24 h) and possessed advantages of acid tolerance (work at pH = 4.0), working under a broad range of temperatures (22–42 °C), and a capability of transforming ZEA at high concentrations (up to 200 µg/mL). In addition, 23 Bacillus strains of various species were tested for their ZEA phosphorylation activity. Thirteen of the Bacillus strains showed phosphorylation functionality at an efficacy of between 20.3% and 99.4% after 24 h incubation, suggesting the metabolism pathway is widely conserved in Bacillus spp. This study established a new transformation system for potential application of controlling ZEA although the metabolism and toxicity of ZEA-14-phosphate requires further investigation.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1658
Author(s):  
Jan C. Plaizier ◽  
Anne-Mette Danscher ◽  
Paula A. Azevedo ◽  
Hooman Derakhshani ◽  
Pia H. Andersen ◽  
...  

The effects of a subacute ruminal acidosis (SARA) challenge on the composition of epimural and mucosa-associated bacterial communities throughout the digestive tract were determined in eight non-lactating Holstein cows. Treatments included feeding a control diet containing 19.6% dry matter (DM) starch and a SARA-challenge diet containing 33.3% DM starch for two days after a 4-day grain step-up. Subsequently, epithelial samples from the rumen and mucosa samples from the duodenum, proximal, middle and distal jejunum, ileum, cecum and colon were collected. Extracted DNA from these samples were analyzed using MiSeq Illumina sequencing of the V4 region of the 16S rRNA gene. Distinct clustering patterns for each diet existed for all sites. The SARA challenge decreased microbial diversity at all sites, with the exception of the middle jejunum. The SARA challenge also affected the relative abundances of several major phyla and genera at all sites but the magnitude of these effects differed among sites. In the rumen and colon, the largest effects were an increase in the relative abundance of Firmicutes and a reduction of Bacteroidetes. In the small intestine, the largest effect was an increase in the relative abundance of Actinobacteria. The grain-based SARA challenge conducted in this study did not only affect the composition and cause dysbiosis of epimural microbiota in the rumen, it also affected the mucosa-associated microbiota in the intestines. To assess the extent of this dysbiosis, its effects on the functionality of these microbiota must be determined in future.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Sesilje Weiss ◽  
David Taggart ◽  
Ian Smith ◽  
Kristofer M. Helgen ◽  
Raphael Eisenhofer

Abstract Background Marsupials are born much earlier than placental mammals, with most crawling from the birth canal to the protective marsupium (pouch) to further their development. However, little is known about the microbiology of the pouch and how it changes throughout a marsupial’s reproductive cycle. Here, using stringent controls, we characterized the microbial composition of multiple body sites from 26 wild Southern Hairy-nosed Wombats (SHNWs), including pouch samples from animals at different reproductive stages. Results Using qPCR of the 16S rRNA gene we detected a microbial community in the SHNW pouch. We observed significant differences in microbial composition and diversity between the body sites tested, as well as between pouch samples from different reproductive stages. The pouches of reproductively active females had drastically lower microbial diversity (mean ASV richness 19 ± 8) compared to reproductively inactive females (mean ASV richness 941 ± 393) and were dominated by gram positive bacteria from the Actinobacteriota phylum (81.7–90.6%), with the dominant families classified as Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, and Dietziaceae. Three of the five most abundant sequences identified in reproductively active pouches had closest matches to microbes previously isolated from tammar wallaby pouches. Conclusions This study represents the first contamination-controlled investigation into the marsupial pouch microbiota, and sets a rigorous framework for future pouch microbiota studies. Our results indicate that SHNW pouches contain communities of microorganisms that are substantially altered by the host reproductive cycle. We recommend further investigation into the roles that pouch microorganisms may play in marsupial reproductive health and joey survival.


2005 ◽  
Vol 71 (9) ◽  
pp. 5138-5144 ◽  
Author(s):  
ChoongSoo Yun ◽  
Daiki Amakata ◽  
Yasuhiro Matsuo ◽  
Hideyuki Matsuda ◽  
Makoto Kawamukai

ABSTRACT The betaproteobacterium Mitsuaria chitosanitabida (formerly Matsuebacter chitosanotabidus) 3001 produces a chitosanase (ChoA) that is classified in glycosyl hydrolase family 80. While many chitosanase genes have been isolated from various bacteria to date, they show limited homology to the M. chitosanitabida 3001 chitosanase gene (choA). To investigate the phylogenetic distribution of chitosanases analogous to ChoA in nature, we identified 67 chitosan-degrading strains by screening and investigated their physiological and biological characteristics. We then searched for similarities to ChoA by Western blotting and Southern hybridization and selected 11 strains whose chitosanases showed the most similarity to ChoA. PCR amplification and sequencing of the chitosanase genes from these strains revealed high deduced amino acid sequence similarities to ChoA ranging from 77% to 99%. Analysis of the 16S rRNA gene sequences of the 11 selected strains indicated that they are widely distributed in the β and γ subclasses of Proteobacteria and the Flavobacterium group. These observations suggest that the ChoA-like chitosanases that belong to family 80 occur widely in a broad variety of bacteria.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 728
Author(s):  
Bao-Gui Jiang ◽  
Ai-Qiong Wu ◽  
Jia-Fu Jiang ◽  
Ting-Ting Yuan ◽  
Qiang Xu ◽  
...  

A novel Borrelia species, Candidatus Borrelia javanense, was found in ectoparasite ticks, Amblyomma javanense, from Manis javanica pangolins seized in anti-smuggling operations in southern China. Overall, 12 tick samples in 227 (overall prevalence 5.3%) were positive for Candidatus B. javanense, 9 (5.1%) in 176 males, and 3 (5.9%) in 51 females. The phylogenetic analysis, based on the 16S rRNA gene and the flagellin gene sequences of the Borrelia sp., exhibited strong evidence that Candidatus B. javanense did not belong to the Lyme disease Borrelia group and the relapsing fever Borrelia group but another lineage of Borrelia. The discovery of the novel Borrelia species suggests that A. javanense may be the transmit vector, and the M. javanica pangolins should be considered a possible origin reservoir in the natural circulation of these new pathogens. To our knowledge, this is the first identification of a novel Borrelia species agent in A. javanense from pangolins. Whether the novel agent is pathogenic to humans is unknown and needs further research.


2014 ◽  
Vol 64 (Pt_3) ◽  
pp. 781-786 ◽  
Author(s):  
Maximo Sánchez ◽  
Martha-Helena Ramírez-Bahena ◽  
Alvaro Peix ◽  
María J. Lorite ◽  
Juan Sanjuán ◽  
...  

Strain S658T was isolated from a Lotus corniculatus nodule in a soil sample obtained in Uruguay. Phylogenetic analysis of the 16S rRNA gene and atpD gene showed that this strain clustered within the genus Phyllobacterium . The closest related species was, in both cases, Phyllobacterium trifolii PETP02T with 99.8 % sequence similarity in the 16S rRNA gene and 96.1 % in the atpD gene. The 16S rRNA gene contains an insert at the beginning of the sequence that has no similarities with other inserts present in the same gene in described rhizobial species. Ubiquinone Q-10 was the only quinone detected. Strain S658T differed from its closest relatives through its growth in diverse culture conditions and in the assimilation of several carbon sources. It was not able to reproduce nodules in Lotus corniculatus. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain should be classified as a representative of a novel species of the genus Phyllobacterium , for which the name Phyllobacterium loti sp. nov. is proposed. The type strain is S658T( = LMG 27289T = CECT 8230T).


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