Research Articles
The first taxonomic and functional characterization of human CAVD-associated microbiota
Lavinia Curini1,#, Brunilda Alushi2,#, Mary Roxana Christopher3, Simone Baldi1, Leandro Di Gloria4, Pierluigi Stefano5, Anna Laganà5, Luisa Iannone5, Herko Grubitzsch6, Ulf Landmesser7, Matteo Ramazzotti4, Elena Niccolai1,§, Alexander Lauten2,§ and Amedeo Amedei1,8,§
Calcific aortic valve disease (CAVD) is the most common heart valve disorder, defined by a remodeling multistep process. In this study, we aimed to investigate and characterize the presence of valvular microbiota and the associated immune response in human CAV samples originating from two European populations.
Cellular cholesterol licenses Legionella pneumophila intracellular replication in macrophages
Edna Ondari1,#, Ashley Wilkins1,#, Brian Latimer3, Ana-Maria Dragoi2,3 and Stanimir S. Ivanov1
Host membranes are inherently critical for niche homeostasis of vacuolar pathogens such as Legionella. One membrane component that is often subverted by vacuolar bacteria is cholesterol. We provide experimental evidence that cellular cholesterol promotes L. pneumophila replication within a membrane bound organelle in infected macrophages.
DadY (PA5303) is required for fitness of Pseudomonas aeruginosa when growth is dependent on alanine catabolism
Ronnie L. Fulton1 and Diana M. Downs1
Pseudomonas aeruginosa inhabits diverse environmental niches that can have varying nutrient composition. The ubiquity of this organism is facilitated by a metabolic strategy that preferentially utilizes low-energy, non-fermentable organic acids, such as amino acids, rather than the high-energy sugars preferred by many other microbes. The amino acid alanine is among the preferred substrates of P. aeruginosa. The dad locus encodes the constituents of the alanine catabolic pathway of P. aeruginosa. Physiological roles for DadR (AsnC-type transcriptional activator), DadX (alanine racemase), and DadA (D-amino acid dehydrogenase) have been defined in this pathway. An additional protein, PA5303, is encoded in the dad locus in P. aeruginosa. PA5303 is a member of the ubiquitous Rid protein superfamily and is designated DadY based on the data presented herein. (...)
Multiple genome analysis of Candida glabrata clinical isolates renders new insights into genetic diversity and drug resistance determinants
Pedro Pais1,2,3,#, Mónica Galocha1,2,3,#, Azusa Takahashi-Nakaguchi4, Hiroji Chibana4 and Miguel C. Teixeira1,2,3
The emergence of drug resistance significantly hampers the treatment of human infections, including those caused by fungal pathogens such as Candida species. Candida glabrata ranks as the second most common cause of candidiasis worldwide, supported by rapid acquisition of resistance to azole and echinocandin antifungals frequently prompted by single nucleotide polymorphisms (SNPs) in resistance associated genes, such as PDR1 (azole resistance) or FKS1/2 (echinocandin resistance). To determine the frequency of polymorphisms and genome rearrangements as the possible genetic basis of C. glabrata drug resistance, we assessed genomic variation across 94 globally distributed isolates with distinct resistance phenotypes, whose sequence is deposited in GenBank. The(...)
Up-regulation of Osh6 boosts an anti-aging membrane trafficking pathway toward vacuoles
Ilham Kadhim1, Nazneen Begum1, William King1, Licheng Xu1 and Fusheng Tang1
Members of the family of oxysterol-binding proteins mediate non-vesicular lipid transport between membranes and contribute to longevity in different manners. We previously found that a 2-fold up-regulation of Osh6, one of seven yeast oxysterol-binding proteins, remedies vacuolar morphology defects in mid-aged cells, partly down-regulates the target of rapamycin complex 1 (TORC1), and increases the replicative lifespan. At the molecular level, Osh6 transports phosphatidylserine (PS) and phosphatidylinositol-4-phosphate (PI4P) between the endoplasmic reticulum (ER) and the plasma membrane (PM). To decipher how an ER-PM working protein controls vacuolar morphology, we tested genetic interactions between OSH6 and DRS2, whose protein flips PS from the lumen to the cytosolic side of the Golgi, the organelle between ER and vacuoles in many pathways. Up-regulated (...)
Air- and dustborne fungi in repositories of the National Archive of the Republic of Cuba
Sofia Borrego1, Isbel Vivar1 and Alian Molina1
This study has as objectives to determine the concentration and diversity of the air- and dustborne mycobiota in seven National Archive of the Republic of Cuba repositories, and to assess the potential risk of biodeterioration that iso-lated taxa may have. In the indoor and outdoor environmental microbiological samplings a SAS biocollector was used and the indoor/outdoor (I/O) ratio was determined for each repository. The settled dust was collected during six months. Sørensen's coefficient of similarity (QS) was calculated to compare the isolated taxa among the three studied niches (indoor air, dust, outdoor air). The biodegradation potential of the isolated taxa was determined by semi-quantitative tests. The concentrations in the air of repositories with natural cross-ventilation ranged from 225.2-750.3 CFU m-3, while in the Map library with air-conditioning (...)
Cleavage-defective Topoisomerase I mutants sharply increase G-quadruplex-associated genomic instability
Alexandra Berroyer1,2, Albino Bacolla3, John A. Tainer2,3,4 and Nayun Kim1,2
Topoisomerase 1 (Top1) removes transcription-associated helical stress to suppress G4-formation and its induced recombination at genomic loci containing guanine-run containing sequences. Interestingly, Top1 binds tightly to G4 structures, and its inhibition or depletion can cause elevated instability at these genomic loci. Top1 is targeted by the widely used anti-cancer chemotherapeutic camptothecin (CPT) and its derivatives, which stabilize Top1 covalently attached on a DNA nick and prevent the re-ligation step. Here we investigated how CPT-resistance conferring Top1 mutants, which emerge in cancer patients and cells treated with CPT, affect G4-induced genomic instability in S. cerevisiae. We found that Top1 mutants form stable complexes with G4 DNA and that expression of Top1 cleavage-defective mutants but not a DNA-binding-defective (...)
Chromosome-condensed G1 phase yeast cells are tolerant to desiccation stress
Zhaojie Zhang1 and Gracie R. Zhang2
The budding yeast Saccharomyces cerevisiae is capable of surviving extreme water loss for a long time. However, less is known about the mechanism of its desiccation tolerance. In this study, we revealed that in an exponential culture, all desiccation tolerant yeast cells were in G1 phase and had condensed chromosomes. (...)
Forced association of SARS-CoV-2 proteins with the yeast proteome perturb vesicle trafficking
Cinzia Klemm1,#, Henry Wood1,#, Grace Heredge Thomas1,#, Guðjón Ólafsson1,2, Mara Teixeira Torres1 and Peter H. Thorpe1
This work demonstrates that the yeast Synthetic Physical Interactions method is a rapid way to identify potential functions of ectopic viral proteins.
Chromosome-condensed G1 phase yeast cells are tolerant to desiccation stress
November 26, 2021
The budding yeast Saccharomyces cerevisiae is capable of surviving extreme water loss for a long time. However, less is known about the mechanism of its desiccation tolerance. In this study, we revealed that in an exponential culture, all desiccation tolerant yeast cells were in G1 phase and had condensed chromosomes. (...)
Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its first variants in fourplex real-time quantitative reverse transcription-PCR assays
November 25, 2021
The early diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is required to identify and isolate contagious patients to prevent further transmission of SARS-CoV-2. In this study, we present a multitarget real-time TaqMan reverse transcription PCR (rRT-PCR) assay for the quantitative detection of SARS-CoV-2 and some of its circulating variants harboring mutations that give the virus a selective advantage. Seven different primer-probe sets that included probes containing locked nucleic acid (LNA) nucleotides were designed to amplify specific wild-type and mutant sequences in Orf1ab, Envelope (E), Spike (S), and Nucleocapsid (N) genes (...)
Forced association of SARS-CoV-2 proteins with the yeast proteome perturb vesicle trafficking
October 27, 2021
This work demonstrates that the yeast Synthetic Physical Interactions method is a rapid way to identify potential functions of ectopic viral proteins.
Airborne bacteria in show caves from Southern Spain
July 26, 2021
This study analyzes the factors conditioning the diversity of airborne bacteria recorded in three Andalusian show caves, subjected to different managements.
Landscapes and bacterial signatures of mucosa-associated intestinal microbiota in Chilean and Spanish patients with inflammatory bowel disease
June 18, 2021
This study investigates the landscapes and alterations of mucosa-associated intestinal microbiota in patients with inflammatory bowel diseases, which cause chronic inflammation of the gut, including ulcerative colitis and Crohn’s disease.
Genome, transcriptome and secretome analyses of the antagonistic, yeast-like fungus Aureobasidium pullulans to identify potential biocontrol genes
June 8, 2021
This study highlights the value of a sequential approach starting with genome mining and consecutive transcriptome and secretome analyses in order to identify a limited number of potential target genes for detailed, functional analyses in Aureobasidium pullulans.
Proanthocyanidin-enriched cranberry extract induces resilient bacterial community dynamics in a gnotobiotic mouse model
April 29, 2021
This study investigates the effect of a water-soluble, proanthocyanidin-rich cranberry juice extract on the short-term dynamics of a human-derived bacterial community in a gnotobiotic mouse model.
Dry biocleaning of artwork: an innovative methodology for Cultural Heritage recovery?
April 15, 2021
This work proposes an innovative methodology based on applied biotechnology for the recovery of altered stonework: the "dry biocleaning", which envisages the use of dehydrated microbial cells without the use of free water or gel-based matrices.
Aeration mitigates endoplasmic reticulum stress in Saccharomyces cerevisiae even without mitochondrial respiration
March 31, 2021
This work demonstrates a scenario, in which aeration acts beneficially on Saccharmyces cerevisiae cells even under fermentative conditions.