scholarly journals A new report on gene expression of three killer toxin genes with antimicrobial activity of two killer toxins in Iraq

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Najwa Mohammed Jameel Ali Abu-Mejdad ◽  
Adnan I. Al-Badran ◽  
Abdullah H. Al-Saadoon ◽  
Mohammed Hussein Minati
Keyword(s):  
Gene Expression ◽  
Extracellular Enzymes ◽  
Killer Toxin ◽  
Bacterial Strains ◽  
Ascomycetous Yeast ◽  
Torulaspora Delbrueckii ◽  
Wickerhamomyces Anomalus ◽  
Toxin Genes ◽  
Killer Toxins ◽  
Type Strains

Abstract Background The K1, K2, and K28 toxins are usually encoded by several cytoplasmically genetic satellite dsRNAs (M1, M2, and M28), which are encapsulated with virus-like particles (VLPs) and reliant on an additional assembly of assistant yeast viruses (L-A) for their reproduction and encapsidation. Ascomycetous yeast species that have these VLPs are especially attractive targets for finding killer toxins like proteins. This is because the organisms are known in producing a large variety of secondary metabolites and extracellular enzymes, which have medical importance as alternative drugs for resistance bacterial strains, particularly multi-resistance drugs (MRD). Results For the first time, 31 type strains of yeasts were tested for killer toxin production in Iraq via the measurement of gene expression of three killer toxin genes (M1, M2, and M28) within the mycovirus in yeasts. All the type strains gave an expression for the three killer toxins with variable levels. The highest expression was recorded for the killer toxin genes in Torulaspora delbrueckii followed by Wickerhamomyces anomalus. Determined antibacterial activity of two killer toxins appeared with high inhibition zone against pathogenic strains of bacteria. Cytotoxicity against human blood cells was not found. These results considered the first record of killer toxins isolated from type strains in Iraq. Conclusion The two typical strains Torulaspora delbrueckii and Wickerhamomyces anomalus showed the highest level of gene expression for the three killer toxins.

The killer yeast Wickerhamomyces anomalus Cf20 exerts a broad anti-Candida activity through the production of killer toxins and volatile compounds

2020 ◽  
Vol 58 (8) ◽  
pp. 1102-1113 ◽  
Author(s):  
Miguel Fernández de Ullivarri ◽  
Gabriela A Bulacios ◽  
Silvia A Navarro ◽  
Lucía Lanza ◽  
Lucia M Mendoza ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Volatile Compounds ◽  
Opportunistic Infections ◽  
Killer Toxin ◽  
Fungal Growth ◽  
Candida Spp ◽  
Killer Yeast ◽  
Wickerhamomyces Anomalus ◽  
Fungistatic Activity ◽  
Killer Toxins

Abstract Candidiasis is a group of opportunistic infections caused by yeast of the genus Candida. The appearance of drug resistance and the adverse effects of current antifungal therapies require the search for new, more efficient therapeutic alternatives. Killer yeasts have aroused as suitable candidates for mining new antifungal compounds. Killer strains secrete antimicrobial proteins named killer toxins, with promissory antifungal activity. Here we found that the killer yeast Wickerhamomyces anomalus Cf20 and its cell-free supernatant (CFS) inhibited six pathogenic strains and one collection strain of Candida spp. The inhibition is mainly mediated by secreted killer toxins and, to a lesser extent, by volatile compounds such as acetic acid and ethyl acetate. A new large killer toxin (>180 kDa) was purified, which exerted 70–74% of the total CFS anti-Candida activity, and the previously described glucanase KTCf20 was inhibitory in a lesser extent as well. In addition, we demonstrated that Cf20 possesses the genes encoding for the β-1,3-glucanases WaExg1 and WaExg2, proteins with extensively studied antifungal activity, particularly WaExg2. Finally, the 10-fold concentrated CFS exerted a high candidacidal effect at 37°C, completely inhibiting the fungal growth, although the nonconcentrated CFS (RCF 1) had very limited fungistatic activity at this temperature. In conclusion, W. anomalus Cf20 produces different low and high molecular weight compounds with anti-Candida activity that could be used to design new therapies for candidiasis and as a source for novel antimicrobial compounds as well.

scholarly journals Formulation and Safety Tests of a Wickerhamomyces anomalus–Based Product: Potential Use of Killer Toxins of a Mosquito Symbiotic Yeast to Limit Malaria Transmission

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 676
Author(s):  
Alessia Cappelli ◽  
Consuelo Amantini ◽  
Federica Maggi ◽  
Guido Favia ◽  
Irene Ricci
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Killer Toxin ◽  
Symbiotic Association ◽  
Proinflammatory Response ◽  
Anopheles Mosquitoes ◽  
Wickerhamomyces Anomalus ◽  
Killer Toxins ◽  
Stable Product ◽  
Potential Use

Wickerhamomyces anomalus strain WaF17.12 is a yeast with an antiplasmodial property based on the production of a killer toxin. For its symbiotic association with Anopheles mosquitoes, it has been proposed for the control of malaria. In an applied view, we evaluated the yeast formulation by freeze-drying WaF17.12. The study was carried out by comparing yeast preparations stored at room temperature for different periods, demonstrating that lyophilization is a useful method to obtain a stable product in terms of cell growth reactivation and maintenance of the killer toxin antimicrobial activity. Moreover, cytotoxic assays on human cells were performed, showing no effects on the cell viability and the proinflammatory response. The post-formulation effectiveness of the killer toxin and the safety tests indicate that WaF17.12 is a promising bioreagent able to impair the malaria parasite in vector mosquitoes.

scholarly journals Role of RNase Y in Clostridium perfringens mRNA Decay and Processing

2016 ◽  
Vol 199 (2) ◽  
Author(s):  
Nozomu Obana ◽  
Kouji Nakamura ◽  
Nobuhiko Nomura
Keyword(s):  
Gene Expression ◽  
Clostridium Perfringens ◽  
Extracellular Enzymes ◽  
Rna Degradation ◽  
Gram Positive ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Toxin Genes ◽  
Rnase Y

ABSTRACT RNase Y is a major endoribonuclease that plays a crucial role in mRNA degradation and processing. We study the role of RNase Y in the Gram-positive anaerobic pathogen Clostridium perfringens, which until now has not been well understood. Our study implies an important role for RNase Y-mediated RNA degradation and processing in virulence gene expression and the physiological development of the organism. We began by constructing an RNase Y conditional knockdown strain in order to observe the importance of RNase Y on growth and virulence. Our resulting transcriptome analysis shows that RNase Y affects the expression of many genes, including toxin-producing genes. We provide data to show that RNase Y depletion repressed several toxin genes in C. perfringens and involved the virR-virS two-component system. We also observe evidence that RNase Y is indispensable for processing and stabilizing the transcripts of colA (encoding a major toxin collagenase) and pilA2 (encoding a major pilin component of the type IV pili). Posttranscriptional regulation of colA is known to be mediated by cleavage in the 5′ untranslated region (5′UTR), and we observe that RNase Y depletion diminishes colA 5′UTR processing. We show that RNase Y is also involved in the posttranscriptional stabilization of pilA2 mRNA, which is thought to be important for host cell adherence and biofilm formation. IMPORTANCE RNases have important roles in RNA degradation and turnover in all organisms. C. perfringens is a Gram-positive anaerobic spore-forming bacterial pathogen that produces numerous extracellular enzymes and toxins, and it is linked to digestive disorders and disease. A highly conserved endoribonuclease, RNase Y, affects the expression of hundreds of genes, including toxin genes, and studying these effects is useful for understanding C. perfringens specifically and RNases generally. Moreover, RNase Y is involved in processing specific transcripts, and we observed that this processing in C. perfringens results in the stabilization of mRNAs encoding a toxin and bacterial extracellular apparatus pili. Our study shows that RNase activity is associated with gene expression, helping to determine the growth, proliferation, and virulence of C. perfringens.

scholarly journals Pathovar Transcriptomes

mSystems ◽  
2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Amy Platenkamp ◽  
Jay L. Mellies
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Regulatory Networks ◽  
Virulence Gene ◽  
Model System ◽  
Genomic Sequences ◽  
Bacterial Strains ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Link Type

ABSTRACT Archetypal pathogenic bacterial strains are often used to elucidate regulatory networks of an entire pathovar, which encompasses multiple lineages and phylogroups. With enteropathogenic Escherichia coli (EPEC) as a model system, Hazen and colleagues (mSystems 6:e00024-17, 2017, https://doi.org/10.1128/mSystems.00024-17 ) used 9 isolates representing 8 lineages and 3 phylogroups to find that isolates with similar genomic sequences exhibit similarities in global transcriptomes under conditions of growth in medium that induces virulence gene expression, and they found variation among individual isolates. Archetypal pathogenic bacterial strains are often used to elucidate regulatory networks of an entire pathovar, which encompasses multiple lineages and phylogroups. With enteropathogenic Escherichia coli (EPEC) as a model system, Hazen and colleagues (mSystems 6:e00024-17, 2017, https://doi.org/10.1128/mSystems.00024-17 ) used 9 isolates representing 8 lineages and 3 phylogroups to find that isolates with similar genomic sequences exhibit similarities in global transcriptomes under conditions of growth in medium that induces virulence gene expression. They also found variation among individual isolates. Their work illustrates the importance of moving beyond observing regulatory phenomena of a limited number of regulons in a few archetypal strains, with the possibility of correlating clinical symptoms to key transcriptional pathways across lineages and phylogroups.

scholarly journals Candida tibetensis sp. nov. and Candida linzhiensis sp. nov., novel anamorphic, ascomycetous yeast species from Tibet

2006 ◽  
Vol 56 (5) ◽  
pp. 1153-1156 ◽  
Author(s):  
Zuo-Wei Wu ◽  
Feng-Yan Bai
Keyword(s):  
Novel Species ◽  
Physiological Property ◽  
Rrna Gene ◽  
Ascomycetous Yeast ◽  
Domain Sequence ◽  
Yeast Strains ◽  
D2 Domain ◽  
Respective Type ◽  
26S Rrna ◽  
Type Strains

Three anamorphic, ascomycetous yeast strains isolated from plant samples collected in Linzhi District, Tibet, China, were revealed as representing two novel species by 26S rRNA gene D1/D2 domain sequence and physiological property comparisons. The names Candida tibetensis sp. nov. and Candida linzhiensis sp. nov. are proposed for these novel species, with XZ 41-6T (=AS 2.3072T=CBS 10298T) and XZ 92-1T (=AS 2.3073T=CBS 10299T) as the respective type strains. D1/D2 sequence analysis showed that C. tibetensis and C. linzhiensis are closely related to Candida caryicola and Candida sequanensis, respectively.

scholarly journals Production of β-Lactamase Inhibitors by Streptomyces Species

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 61 ◽  
Author(s):  
Daniela Viana Marques ◽  
Suellen Machado ◽  
Valéria Ebinuma ◽  
Carolina Duarte ◽  
Attilio Converti ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Cost Effective ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Streptomyces Species ◽  
Innovative Strategies ◽  
New Antibiotics ◽  
Microbial Products ◽  
Type Strains ◽  
Streptomyces Genus

β-Lactamase inhibitors have emerged as an effective alternative to reduce the effects of resistance against β-lactam antibiotics. The Streptomyces genus is known for being an exceptional natural source of antimicrobials and β-lactamase inhibitors such as clavulanic acid, which is largely applied in clinical practice. To protect against the increasing prevalence of multidrug-resistant bacterial strains, new antibiotics and β-lactamase inhibitors need to be discovered and developed. This review will cover an update about the main β-lactamase inhibitors producers belonging to the Streptomyces genus; advanced methods, such as genetic and metabolic engineering, to enhance inhibitor production compared with wild-type strains; and fermentation and purification processes. Moreover, clinical practice and commercial issues are discussed. The commitment of companies and governments to develop innovative strategies and methods to improve the access to new, efficient, and potentially cost-effective microbial products to combat the antimicrobial resistance is also highlighted.

scholarly journals Novel Psychrophiles and Exopolymers from Permafrost Thaw Lake Sediments

2020 ◽  
Vol 8 (9) ◽  
pp. 1282
Author(s):  
Ilaria Finore ◽  
Adrien Vigneron ◽  
Warwick F. Vincent ◽  
Luigi Leone ◽  
Paola Di Donato ◽  
...  
Keyword(s):  
Extracellular Enzymes ◽  
Extreme Environments ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Ice Melt ◽  
Permafrost Thaw ◽  
Phenotypic And Genetic Characterization ◽  
Pseudomonas Extremaustralis ◽  
Commercial Polymers ◽  
Thaw Lakes

Thermokarst lakes are one of the most abundant types of microbial ecosystems in the circumpolar North. These shallow basins are formed by the thawing and collapse of ice-rich permafrost, with subsequent filling by snow and ice melt. Until now, permafrost thaw lakes have received little attention for isolation of microorganisms by culture-based analysis. The discovery of novel psychrophiles and their biomolecules makes these extreme environments suitable sources for the isolation of new strains, including for potential biotechnological applications. In this study, samples of bottom sediments were collected from three permafrost thaw lakes in subarctic Québec, Canada. Their diverse microbial communities were characterized by 16S rRNA gene amplicon analysis, and subsamples were cultured for the isolation of bacterial strains. Phenotypic and genetic characterization of the isolates revealed affinities to the genera Pseudomonas, Paenibacillus, Acinetobacter,Staphylococcus and Sphingomonas. The isolates were then evaluated for their production of extracellular enzymes and exopolymers. Enzymes of potential biotechnological interest included α and β-glucosidase, α and β-maltosidase, β-xylosidase and cellobiohydrolase. One isolate, Pseudomonas extremaustralis strain 2ASCA, also showed the capability to produce, in the loosely bound cell fraction, a levan-type polysaccharide with a yield of 613 mg/L of culture, suggesting its suitability as a candidate for eco-sustainable alternatives to commercial polymers.

scholarly journals RstA Is a Major Regulator ofClostridioides difficileToxin Production and Motility

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Adrianne N. Edwards ◽  
Brandon R. Anjuwon-Foster ◽  
Shonna M. McBride
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Toxin Production ◽  
Toxin Gene ◽  
Dna Binding Domain ◽  
Content Type ◽  
Toxin Genes ◽  
Clostridioides Difficile ◽  
Species Specific ◽  
Toxin Gene Expression

ABSTRACTClostridioides difficileinfection (CDI) is a toxin-mediated diarrheal disease. Several factors have been identified that influence the production of the two majorC. difficiletoxins, TcdA and TcdB, but prior published evidence suggested that additional unknown factors were involved in toxin regulation. Previously, we identified aC. difficileregulator, RstA, that promotes sporulation and represses motility and toxin production. We observed that the predicted DNA-binding domain of RstA was required for RstA-dependent repression of toxin genes, motility genes, andrstAtranscription. In this study, we further investigated the regulation of toxin and motility gene expression by RstA. DNA pulldown assays confirmed that RstA directly binds therstApromoter via the predicted DNA-binding domain. Through mutational analysis of therstApromoter, we identified several nucleotides that are important for RstA-dependent transcriptional regulation. Further, we observed that RstA directly binds and regulates the promoters of the toxin genestcdAandtcdB, as well as the promoters for thesigDandtcdRgenes, which encode regulators of toxin gene expression. Complementation analyses with theClostridium perfringensRstA ortholog and a multispecies chimeric RstA protein revealed that theC. difficileC-terminal domain is required for RstA DNA-binding activity, suggesting that species-specific signaling controls RstA function. Our data demonstrate that RstA is a transcriptional repressor that autoregulates its own expression and directly inhibits transcription of the two toxin genes and two positive toxin regulators, thereby acting at multiple regulatory points to control toxin production.IMPORTANCEClostridioides difficileis an anaerobic, gastrointestinal pathogen of humans and other mammals.C. difficileproduces two major toxins, TcdA and TcdB, which cause the symptoms of the disease, and forms dormant endospores to survive the aerobic environment outside the host. A recently discovered regulatory factor, RstA, inhibits toxin production and positively influences spore formation. Herein, we determine that RstA directly binds its own promoter DNA to repress its own gene transcription. In addition, our data demonstrate that RstA directly represses toxin gene expression and gene expression of two toxin gene activators, TcdR and SigD, creating a complex regulatory network to tightly control toxin production. This study provides a novel regulatory link betweenC. difficilesporulation and toxin production. Further, our data suggest thatC. difficiletoxin production is regulated through a direct, species-specific sensing mechanism.

Sign in / Sign up

Export Citation Format

Share Document