1,721,039 research outputs found
Harnessing the dual nature of W. coagulans for sustainable production of biomaterials and development of functional food
Full text link: Bacillus coagulans, recently renamed Weizmannia coagulans, is a spore-forming bacterium that has garnered significant interest across various research fields, ranging from health to industrial applications. The probiotic properties of W. coagulans enhance intestinal digestion, by releasing prebiotic molecules including enzymes that facilitate the breakdown of not-digestible carbohydrates. Notably, some enzymes from W. coagulans extend beyond digestive functions, serving as valuable biotechnological tools and contributing to more sustainable and efficient manufacturing processes. Furthermore, the homofermentative thermophilic nature of W. coagulans renders it an exceptional candidate for fermenting foods and lignocellulosic residues into L-(+)-lactic acid. In this review, we provide an overview of the dual nature of W. coagulans, in functional foods and for the development of bio-based materials
Unravelling the role of the F55 regulator in the transition from lysogeny to UV induction of Sulfolobus spindle-shaped virus 1
Full text linkAbstract
Sulfolobus spindle-shaped virus 1 represents a model for studying virus-host interaction in harsh environments, and it is so far the only member of the family Fuselloviridae that shows a UV-inducible life cycle. Although the virus has been extensively studied, mechanisms underpinning the maintenance of lysogeny as well as those regulating the UV induction have received little attention. Recently, a novel SSV1 transcription factor, F55, was identified. This factor was able to bind in vitro to several sequences derived from the early and UV-inducible promoters of the SSV1 genome. The location of these binding sites together with the differential affinity of F55 for these sequences led to the hypothesis that this protein might be involved in the maintenance of the SSV1 lysogeny. Here, we report an in vivo survey of the molecular events occurring at the UV-inducible region of the SSV1 genome, with a focus on the binding profile of F55 before and after the UV irradiation. The binding of F55 to the target promoters correlates with transcription repression, whereas its dissociation is paralleled by transcription activation. Therefore, we propose that F55 acts as a molecular switch for the transcriptional regulation of the early viral genes
Responding to toxic compounds: a genomic and functional overview of Archaea
No full textArchaea occupy a considerable diversity of niches ranging from extreme of pH, salinity to temperature that cannot be tolerated by other forms of life. There is an increasing consciousness that they have a key role both on the biogeochemical cycling of elements and in the bioremediation of polluted habitat. A greater understanding of metal homeostasis and resistance to toxic compounds in this life domain is required to design new strategies for the bioremediation of contaminated sites. This review describes the strategies developed by Archaea to transform xenobiotic compounds and metal ions present in the environment. The adaptation and/or response to such chemicals and the molecular mechanisms of resistance evolved in Archaea are discussed
Biofilm formation upon virus infection in Sulfolobus solfataricus.
No full textThe hyperthermophilic crenarchaeote Sulfolobus solfataricus is a facultative autotroph with the ability to grow under aerobic conditions. The genome of several Sulfolobus species has been sequenced making Sulfolobus spp. model organisms for studying molecular and physiological processes in Archaea.
Information about biofilm formation in Archaea is still at the stage of infancy. Recently, it has been shown that S. solfataricus forms a biofilm mainly made of polysaccharides upon attachment to various surfaces, such as glass, mica etc. The genes possibly involved in the production of the extracellular polysaccharides have been identified (1).
We have investigated the ability of S. solfataricus to form biofilm as a stress response to the infection with the Spindle-shaped virus 2 (SSV2) (2). After prolonged growth on solid medium of a lawn of S. solfataricus cells spotted with SSV2, production of a white and dense material was observed. Formation of a white matrix was also observed in cells non-infected but grown at high density. The protein fraction of the white matrix was found to be very low and, although not confirmed, it is likely that the white matrix is an exopolysaccharide. We therefore suggest that the formation of the white matrix could be controlled by quorum sensing and cellular stress responses in order to protect cells from external factors.
The physiology of the process as well as the chemical composition of the biolfilm-like white matrix, is under way
An autonomously replicating transforming vector for Sulfolobus solfataricus.
No full textA plasmid able to transform and to be stably maintained both in Sulfolobus solfataricus and in Escherichia coli was constructed by insertion into an E. coli plasmid of the autonomously replicating sequence of the virus particle SSV1 and a suitable mutant of the hph (hygromycin phosphotransferase) gene as the transformation marker. The vector suffered no rearrangement and/or chromosome integration, and its copy number in Sulfolobus was increased by exposure of the cells to mitomycin C
The Ssadh Promoter and the pEXSs Vector: an Integrated Genetic System for in vitro and in vivo Gene Regulation Analysis and Heterologous Expression in Sulfolobus solfataricus
No full textTlys, a novel identified SSV1 transcript expressed in the lysogenic state, encodes for a DNA-binding protein interacting at the promoters of the early genes.
Full text linkWhile studying the gene expression of the Sulfolobus spindle-shaped virus 1 (SSV1) in Sulfolobus solfataricus lysogenic cells, a novel viral transcript (Tlys) was identified. Transcriptional analysis revealed that Tlys is expressed only in the absence of UV irradiation and is downregulated during the growth of the lysogenic host. The correponding gene f55 lies between two transcriptional units (T6 and Tind) that are upregulated upon UV irradiation. The open reading frame f55 encodes a 6.3-kDa protein which shows sequence identity with negative regulators that fold into the ribbon-helix-helix DNA-binding motif. DNA-binding assays demonstrated that the recombinant F55, purified from Escherichia coli, is indeed a putative transcription factor able to recognize site specifically target sequences in the promoters of the early induced T5, T6, and Tind transcripts, as well as of its own promoter. Binding sites of F55 are included within a tandem-repeated sequence overlapping the transcription start sites and/or the B recognition element of the pertinent genes. The strongest binding was observed with the promoters of T5 and T6, and an apparent cooperativity in binding was observed with the Tind promoter. Taking together the transcriptional analysis data and the biochemical evidences, we surmise that the protein F55 is involved in the regulation of the lysogenic state of SSV1
A spreadable, non-integrative and high copy number shuttle vector for Sulfolobus solfataricus based on the genetic element pSSVx from Sulfolobus islandicus.
No full textThe pSSVx genetic element from Sulfolobus islandicus REY15/4 is a hybrid between a plasmid and a fusellovirus, able to be maintained in non-integrative form and to spread when the helper SSV2 virus is present in the cells. In this work, the satellite virus was engineered to obtain an Escherichia coli-Sulfolobus solfataricus shuttle vector for gene transfer and expression in S.solfataricus by fusing site-specifically the pSSVx chromosome with an E.coli plasmid replicon and the ampicillin resistance gene. The pSSVx-based vector was proven functional like the parental virus, namely it was able to spread efficiently through infected S.solfataricus cells. Moreover, the hybrid plasmid stably transformed S.solfataricus and propagated with no rearrangement, recombination or integration into the host chromosome. The high copy number of the artificial genetic element was found comparable with that calculated for the wild-type pSSVx in the new host cells, with no need of genetic markers for vector maintenance in the cells and for transfomant enrichment.The newly constructed vector was also shown to be an efficient cloning vehicle for the expression of passenger genes in S.solfataricus. In fact, a derivative plasmid carrying an expression cassette of the lacS gene encoding the beta-glycosidase from S.solfataricus under the control of the Sulfolobus chaperonine (thermosome tf55) heat shock promoter was also able to drive the expression of a functional enzyme. Complementation of the beta-galactosidase deficiency in a deletion mutant strain of S.solfataricus demonstrated that lacS gene was an efficient marker for selection of single transformants on solid minimal lactose medium
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