Microbiology Commons^™

Bioactive Potential Of Microbial Isolates From Yoluja Cave And Jepirramüin Rock Shelter, Cabo De La Vela (Colombia), Juan Sebastián López Caro, Virginia Patricia Roa Angulo, Alex Alberto González Vargas

International Journal of Speleology

Subterranean environments harbor diverse microbial communities with significant potential for the production of bioactive compounds. This study evaluated the antimicrobial and antioxidant potential of microbial isolates obtained from Yoluja Cave and the Jepirramüin rock shelter, located in the coastal region of La Guajira, Colombia. Field sampling was conducted during three campaigns in July, September, and November 2025, including soil and surface samples collected along environmental gradients within each site. Microorganisms were isolated using selective culture media and identified through morphological and biochemical characterization. Selected strains were subjected to liquid fermentation and organic solvent extraction to obtain crude metabolites. Analysis of …

Combating Β-Lactamase Resistance: From Inhibitor Design To Substrate Evolution, Lian M.C. Jacobs

USF Tampa Graduate Theses and Dissertations

β-lactamase production by bacteria is a major mechanism of antibiotic resistance. These enzymes hydrolyze β-lactam antibiotics, preventing them from binding to and inhibiting PBPs. Although new β-lactam scaffolds and inhibitors are continually introduced into the clinic, resistance often emerges within a few years. Therefore, the development of cross-class inhibitors with novel scaffolds is critical to mitigate this resistance. In parallel, a deeper understanding of the structural and mechanistic basis of β-lactamase resistance is essential. Together, these approaches provide an effective strategy for combating antibiotic resistance.

The first project addressed the need of effective cross-class β-lactamase inhibitors capable of targeting SBL …

Antimicrobial Resistance Of Cultivable Bacteria Isolated From Sorcerer’S Cave In Texas, Jennifer R. Huddleston, David E. Sanderson, Braden J. Smith, Joshua M. Brokaw, Evan M. Babb, Jeffrey T. Wooliscroft

International Journal of Speleology

Studying caves with minimal human contact offers insights into antimicrobial resistance before human influence. In this study, we isolated 315 bacterial strains from Sorcerer’s Cave in Texas and evaluated their resistance to seven common antimicrobials. Under half (41.4%) of the Gram-positive isolates and 68.4% of the Gram-negative isolates were resistant to three or more antimicrobials. The two most common genera identified were Pseudomonas and Bacillus. Compared to bacteria isolated in previous cave studies, Sorcerer’s Cave bacteria exhibited more extensive antimicrobial resistance. This study underscores the importance of minimally disturbed cave environments in advancing our knowledge of antimicrobial resistance present …

First Report Of A Bat Guano Fire From A Cave In Southeast Asia, Sopark Jantarit, Martin Ellis, Pruet Kalasuwan, Neeranuch Phusunti, Pimonsri Mittraparp-Arthorn, Jiranan Pattano, Arnon Chukamnerd, Turdtun Tong-In, Natthawut Khrueaaunruean

International Journal of Speleology

Fires occurring in cave guano are a rare and unusual phenomenon and the occurrence of such events in Southeast Asia is particularly novel. In this study, we document the first recorded instance of a bat guano fire in a tropical cave at Tham Chao Ram in Sukhothai province, northern Thailand. A bacteriological analysis was made of the guano at the fire site and from a control site within the cave. We give a comprehensive review of global reports on bat guano fires in caves, conduct an initial investigation of the physical factors at the fire site and discuss the potential …

A Multi-Faceted Study Of Antibiotic-Resistant, Opportunistic Pathogens In Wastewater And Environmental Water, Jeanette Calarco

USF Tampa Graduate Theses and Dissertations

More than 2.8 million infections due to antibiotic-resistant bacteria occur annually in the United States, and more than 35,000 people die as a result. Domestic wastewater (sewage), which contains antibiotic-resistant bacteria and antibiotic resistance genes, is collected at treatment plants for removal of contaminants, e.g. pathogenic microorganisms and nutrients. While wastewater treatment is designed to remove antibiotic-resistant bacteria and other microorganisms through treatment and disinfection, some bacteria may escape treatment. Treated wastewater effluent is generally discharged into surface waters; however, some fraction of the effluent may be used as recycled water. Compromised wastewater collection infrastructure and sewage spills can disseminate …

Dissolved Inorganic Carbon Metabolism In Bacteria, Jana Wieschollek

USF Tampa Graduate Theses and Dissertations

Dissolved inorganic carbon (DIC: CO2, HCO3⁻, CO32⁻) plays a central role in the metabolism of all living organisms. DIC is necessary for steps in essential biosynthetic processes, such as the synthesis of amino acids and nucleobases; in autotrophic bacteria, organic molecules are synthesized entirely from DIC. To ensure a steady supply of CO2 and HCO3 - needed for biosynthesis and/or autotrophy, organisms use bicarbonate transporters to increase the cytoplasmic concentration of this anion, and carbonic anhydrase (CA) to speed the interconversion of CO2 and HCO3 -, both in the cytoplasm and at the cell surface. This dissertation investigates DIC metabolism …

First Insight On The Genesis Of Iron Oxide-Hydroxide Biospeleothems In Rancho Chico Lava Tube, Mexico, Rafael López-Martínez, Elizabeth Solleiro-Rebolledo, Rocio Alcántara-Hernández, Teresa Pi Puig, Sergey Sedov, Daisy Valera Fernández, M. Nayeli Luis-Vargas, Yasmany Lima Vera, Jesús Solé, Ramon Espinasa-Pereña

International Journal of Speleology

Iron is a common element in lava tube systems, typically observed as thin crusts or inferred from the reddish coloration of secondary mineral deposits. In this study, we describe iron oxide-hydroxide biospeleothems discovered in the Rancho Chico Lava Tube, located within the Xalapa Monogenetic Volcanic Field in Mexico. We adopt an integrative approach combining petrography, soil micromorphology, scanning electron microscopy, mineralogy, and 16S rRNA gene metabarcoding. DNA sequencing reveals the presence of microorganisms such as Acidithiobacillus, Gallionella, and members of the Leptospirillaceae family, which may be involved in the oxidation of Fe²⁺ within the lava tube. The source …

Identification Of Host Nuclear Factors Exploited By Kshv Lana To Maintain Latency, Anandita Ghosh

USF Tampa Graduate Theses and Dissertations

Kaposi’s Sarcoma Associated Herpes Virus (KSHV or HHV-8) is a γ-herpesvirus implicated in multiple lymphoproliferative human cancers and immune dysregulatory diseases. Like other herpesviruses, KSHV has a biphasic mode of infection primarily orchestrated by two viral proteins: the Latency-Associated Nuclear Antigen (LANA), which promotes viral persistence through latency, and the Replication and Transcription Activator (RTA), which triggers lytic reactivation. During latency, the KSHV genome exists as a highly heterochromatinized, extrachromosomal episome in the nucleus, which can be reverted to euchromatin in response to certain stimuli, like stress. KSHV has evolved to exploit numerous host proteins to orchestrate its lifecycle, especially …

Cyanobacteria And Algae From Chýnov And Koněprusy Caves (Czech Republic), Michaela Wipplingerová, Jan Pokorný, Jan Kaštovský

International Journal of Speleology

Algae and cyanobacteria have been studied in two so far phycologically unexplored show caves (Chýnov and Koněprusy) in the Czech Republic. Taxa were identified morphologically using cultivation and subsequent light microscopy, while problematic cyanobacterial species were verified by sequencing the genes for 16S rRNA and 16S–23S internal transcribed spacer. A total of 13 cyanobacterial taxa were found, two Bacillariophyceae, three Xanthophyceae, four Chlorophyceae, six Trebouxiophyceae, 11 Streptophyta, and three Euglenida; many of these species were found for the first time in the caves. The darker parts of the caves were dominated by cyanobacteria, and green algae were found predominantly right …

Degradation Of Cyanobacteria And Microalgae Using Ultraviolet Radiation At 222 Nm And Its Application In The Bleaching Of Lampenflora On Cave Rock Surfaces, Keisuke Naito, Shuji Watanabe, Masuo Komukai, Takehiro Kazama, Masayuki Itoh, Masahiro Kawasaki

International Journal of Speleology

Cyanobacterial and microalgae blooms negatively affect ecological environments. One of the emerging problems of these blooms occurs in calcareous caves, where visible lighting systems in tourist caves induce the formation of photosynthetic biofilms known as lampenflora on rock surfaces. In this study, we evaluated the inactivation effect of ultraviolet (UV) light irradiation at 222 nm (rare gas halide lamp) and 254 nm (mercury lamp) on cyanobacteria and microalgae in a laboratory and on lampenflora in Ryusenshindo Cave in Japan. Based on the laboratory experiments, irradiation at 222-nm was more effective than that at 254-nm for degrading plants. The photosensitivity of …

The Regulation Of The Secreted Proteases In Usa300 Isolates Of Staphylococcus Aureus, Jessica K. Jackson

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a Gram-positive opportunistic pathogen capable of causing myriad diseases, ranging from skin infections to pneumonia, endocarditis, and sepsis. It does this via the production of an array of virulence factors including toxins, adhesins, immunoglobulin-binding proteins, and proteases. Towards these latter elements, S. aureus produces ten secreted proteases that play a dual role in infection: firstly, by modulating the stability and abundance of other virulence factors, and secondly, by cleaving host factors to facilitate infection. Given their importance, we set out to explore the natural variability of protease production in a collection of clinical isolates from Tampa General …

The Association Between Oral Microbiome, Oral Inflammation, Periodontal Disease, And Systemic Metabolism In Individuals With/Without Type 1 Diabetes, Mianli Xiao

USF Tampa Graduate Theses and Dissertations

This study explores the associations between oral microbiomes, periodontal disease (PD), and systemic metabolism in individuals with and without Type 1 diabetes (T1D). Data were obtained from 208 participants (99 with T1D, 109 non-diabetic) in the Coronary Artery Calcification in Type 1 Diabetes (CACTI) pilot study and 283 participants from the Oral Microbiome ancillary cohort study. Both studies included the collection of saliva or subgingival plaque samples. Microbial DNA was extracted, and the V4 region of the 16S rRNA gene was sequenced using the Illumina MiSeq platform. Machine learning models, including Random Forest (RF) and Multi-layer Perceptron (MLP), were applied …

The Environment Of Glaciovolcanic Caves And Their Value As Planetary Analogues, Christian Stenner, Lee J. Florea, Linda Sobolewski, Andreas Pflitsch, Morgan Cable, Roberto Anitori, Richard E. Davis, Kathleen Graham, Glyn Williams-Jones

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Exploring Biosignatures And Biogeochemical Processes In Lanzarote Lava Tubes: Implications For Martian Analog Research, Vera Palma, Ana Z. Miller, Francesco Sauro, Bogdan P. Onac, José M. De La Rosa, Sara Gutiérrez-Patricio, Beatriz Cubero, José A. Gonzalez-Perez, Jesus Martínez-Frías, A Teresa Caldeira

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

The Ecology Of Chemosynthesis In Submerged Coastal Caves, Robert Scharping, Michael Casso, Isabel Schaal, Paul Henderson, James Garey, Matthew Charette, John Pohlman, Stefan Sievert

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Microbiome Diversity In Acidic Environments - The Case Of The Șesei Valley Tailings Pond, Iulia Lupan

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Exploring Pristine Microbial Ecosystems From The Uninhabited Volcanic Selvagens Islands, Pedro N. Jiménez-Morillo, Sara Gutiérrez-Patricio, Vera Palma, Ana Teresa Caldeira, Nicasio Tomás Jiménez-Morillo, Ana Z. Miller

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Recent Advances In The Microbiology Of Permanently Stratified, Hypersaline Lakes Of Transylvanian Basin (Central Romania), Horia Leonard Banciu, Ionuț Mădălin Gridan, Adrian Vasile Zety, Ioana Drăghici, Cristina Mircea, Michalis Daniel Lazăr, Andreea Melisa Tripon, Doriana Mădălina Buda, Adorján Cristea

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Given To Salt: Novel Insights Into The Diversity Of Halophilic Microorganisms And Their Functioning In Hypersaline Ecosystems, Aharon Oren

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Microbial Colonization Of New Lava Tubes Formed By The Fagradalsfjall Volcano’S Eruption (Iceland), Ettore Lopo, Francesco Sauro, Ana Zelia Miller, Bogdan Petroniu Onac, Martina Cappelletti

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Onsite Microbial Analyses In One Of The Most Remote Quartzite Subterranean Environment On Earth: Imawarì Yeuta On Venezuelan Tepuis, Martina Cappelletti

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

First Biogeochemical Study Of Mira De Aire Cave: The Biggest Karstic System In Portugal, Alba Gómez-Arias, Julio Castillo, Nicasio Tomás Jiménez-Morillo, Beatriz Cubero, Sara Gutiérrez-Patricio, Pedro N. Jimenez-Morillo, José A. Gonzalez-Perez, José M. De La Rosa, Ana Z. Miller

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Sampling And Dna Analysis Of Extreme Environments, Scott Tighe

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

The Ecosystem Of A Remarkable Glaciovolcanic Cave At Mount Meager, British Columbia, Canada, Christian Stenner, Kathleen Graham, Morgan Cable, Glyn Williams-Jones, Jared J. Clance, Jacob Shaffer, Jill Mikucki, Anna Szynkiewicz, Olivia Vinnes, Michael Paton, Jeremy Nash

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Cave Ice Microbiome – Reservoir For New Biomolecules In Medicine And Biotechnologies, Victoria Ioana Paun, Corina Itcus, Carmen Mariana Chifiriuc, Paris Lavin, Cristina Purcarea

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Antarctic Glacier Melting Modeling Distribution Of Bacterial Community Structure, Corina Itcus, Constantin Marin, Soon Gyu Hong, Manuela Elisabeta Sidoroff, Cristian Coman, Cristina Purcarea

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Time-Transgressive Microbial Diversity In A Tropical Bat Guano Accumulation, Deer Cave, Mulu, Borneo, Joyce Lundberg, Donald A. Mcfarlane

International Journal of Speleology

Bat guano accumulations in caves can constitute large deposits of organic material, particularly chitin and its degradation products, that host a diverse microbiome. Previous microbiological studies have not addressed the stratified nature of these deposits in the context of the timeframe of the decomposition process. We present such data (temperature, pH, DNA sampling of eight carbon-dated strata) for a 75 cm-deep tropical guano accumulation that undergoes complete decomposition over a timescale of ~120 years. The aerobic, surface layer of freshly-fallen guano has the greatest diversity of taxa, with Bacteroidota co-dominant with Pseudomonadota, and includes many taxa unique to this …

Group B Streptococcus Intestinal Barrier Disruption And The Protective Role Of Butyrate, Kristen Dominguez

USF Tampa Graduate Theses and Dissertations

Group B Streptococcus (Streptococcus agalactiae; GBS) is a leading cause of neonatal sepsis worldwide. Intrapartum antibiotics in GBS-colonized mothers significantly reduced the incidence of early-onset sepsis occurring in the first week of life; however, there are currently no prophylactic interventions for late-onset sepsis, occurring within the first 3 months of life. GBS is a pathobiont that primarily colonizes the gastrointestinal tract and can cross the intestinal barrier via both the paracellular and transcellular routes, causing invasive disease. Neonatal susceptibility to GBS intestinal translocation is mediated by inadequate epithelial barrier function and microbiome immaturity; however, the mechanisms by which GBS exploits …

Comparing The Genomes Of Multidrug And Vancomycin-Resistant Enterococcus Faecium From A Florida Wastewater Treatment Plant, Eleanor Brodrick

USF Tampa Graduate Theses and Dissertations

Vancomycin-resistant Enterococcus (VRE) are a serious health threat, causing 50,000 infections and 5,000 deaths each year in the United States (CDC, 2019). Multidrug-resistant VRE are becoming more prevalent, and treatment options for infections caused by these organisms are limited (Arias et al., 2010; CDC, 2019). Multidrug resistant VRE have been previously isolated from wastewater in Brazil, Canada, and Portugal (Araújo et al., 2010; de_Farias et al., 2022; Sanderson et al., 2019). Thirteen vancomycin-resistant Enterococcus faecium isolated from three stages of a Florida wastewater treatment plant were fully resistant to the following antibiotics: vancomycin, ampicillin, ciprofloxacin, erythromycin, tetracycline, and nitrofurantoin, and …

Tetr Family Regulator, Farr, Influences Rot-Mediated Control Of Virulence Factor Expression In Staphylococcus Aureus, Julia C. Schumacher

USF Tampa Graduate Theses and Dissertations

Point-mutation variants of the TetR family regulator, FarR, have emerged across Staphylococcus aureus sequence types as conferring antibiotic and fatty acid resistance, particularly in Hospital-Associated Methicillin Resistant S. aureus (HA-MRSA) strains. FarR also exhibits an additional largely uncharacterized relationship to virulence factor production, seemingly through the global repressor of toxins—Rot, which functions to regulate S. aureus’ ability to colonize and persist in the host via a complex cascade of signaling. While Rot protein is post-transcriptionally regulated by the highly characterized Agr system, there is little known about its transcriptional regulation. Herein, we explored these dynamics by initially characterizing virulence phenotypes …