Microbiology Commons^™

Function And Regulation Of Long Polar Fimbriae During Enterohemorrhagic Escherichia Coli Infection, Walter J. Galdamez

Dissertations and Theses (Open Access)

Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen that causes severe gastrointestinal disease and hemolytic uremic syndrome. EHEC employs multiple virulence factors to colonize the host intestine, including the locus of enterocyte effacement (LEE) encoded type III secretion system, intimin, and flagella, yet the role of long polar fimbriae (Lpf) in adhesions and infection remains less well understood. Long polar fimbriae can mediate bacterial attachment to host cells in vitro, yet the regulation and function of its two fimbrial operons, lpf1 and lpf2 in vivo remain poorly understood. Preliminary RNA-seq data from zebrafish infected with EHEC reveal that expression of …

Understanding The Effects Of Simulated Microgravity On Staphylococcus Epidermidis And Escherichia Coli In Co-Culture, Emma Costa, Mitchell K. Villafania, Makaila Olson, Kareigh N. Gammon, Hugo Castillo

Beyond: Undergraduate Research Journal

With the popularity of space travel increasing, it is important to understand the effects of microgravity on microbial communities as alterations on bacterial interactions can occur. Staphylococcus epidermidis and Escherichia coli are bacteria that are commonly found within human microbiomes. S. epidermidis is a cocci-shaped gram-positive bacterium that is part of the human skin microbiome. However, it can gather on sites of open skin and enter the body leading to an infection. E. coli is a rod-shaped gram-negative bacterium that can be found in the human gut microbiome. The pathogenic strains of E. coli have the potential to cause harmful …

Analysis Of Bacterial Virulence And Resistance In A Model Of Recurrent Uti, Rachel L. Proper

Undergraduate Honors Theses

Urinary tract infection (UTI) is a major women’s health issue, affecting approximately 40% of women during their lifetime. Formation of a biofilm by UTI-causing bacteria poses a major challenge in treatment, as the protection provided by the biofilm hinders both host defenses and antibiotic treatment. Failure to eradicate these infections causes them to become recurrent (rUTI). Previous research indicates that rUTI may be comorbid with a mutation in the SERPINE1 gene, which causes fibrin to accumulate within the body. Literature also indicates that fibrin provides a better scaffold for bacterial attachment and, subsequently, biofilm formation. In this work it was …

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 …

Detection Method For Escherichia Coli Using Real-Time Polymerase Chain Reaction Targeting The Yhav Gene, Muktiningsih Nurjayadi, Anisa Fitriyanti, Royna Rahma Musie, Gusti Angieta Putri, Puan Aqila Azizah, Helzi Angelina, Grace Grace, Ananda Indah Putri Sihombing, Agus Setiawan, Jefferson Lynford Declan, Gladys Indira Putri, Dandy Akbar Juliansyah, Siti Fatimah, Ayu Berkahingrum, Irma Ratna Kartika, Fera Kurniadewi, Vira Saamia, Shyi-Tien Chen, Bassam Aboemolak, Hesham Ali El Enshasy

Makara Journal of Science

Escherichia coli is a foodborne pathogenic bacterium that can cause diarrhea, while yhaV is a virulence-associated gene linked to the toxin–antitoxin system in E. coli. This study was aimed at evaluating the confirmation, specificity, and sensitivity of a yhaV gene primer using real-time polymerase chain reaction. The yhaV-targeting PCR successfully amplified a DNA fragment with an amplicon length of 207 bp (base pairs) under an annealing temperature optimized to a range of 54 °C to 62 °C via gradient PCR. The PCR using the primer pair produced a consistent Ct (cycle threshold) of 14.14 ± 0.05 and showed …

Metabolite Analysis To Understand Factors Limiting Microbial Fermentation At High Substrate Concentrations, Bishal D. Sharma

Dartmouth College Ph.D Dissertations

Clostridium thermocellum, a thermophilic anaerobic bacterium, holds promise as a biocatalyst for conversion of lignocellulosic biomass into biofuels. This microbe has been subjected to various metabolic engineering strategies, including the deletion of genes encoding secondary fermentation products such as H₂, formate, acetate, and lactate, as well as the expression of heterologous genes to redirect carbon flux toward ethanol production. Despite these efforts, achieving economically viable ethanol titers remains a challenge. We hypothesized that studying how intracellular metabolite concentrations change as fermentation stops could reveal metabolic bottlenecks or regulatory mechanisms limiting ethanol production at high titers. However, metabolomics studies at …

Reducing Stress: The Role Of The Rcl Operon In Bacterial Stress Response To Hypothiocyanite, Julia Meredith

All ETDs from UAB

The human immune system utilizes a variety of weapons against bacterial communities within the body, which allow it to control the overall microbial population. Understanding how some bacterial species are able to better deal with and survive damage by the immune system while others are not, can help us elucidate the complex relationship between us and our microbiome. One tool that immune cells use for microbial control is the potent oxidant hypothiocyanite/hypothiocyanous acid (-OSCN/HOSCN). The response mounted by Escherichia coli and other bacterial species in order to survive damage caused by HOSCN is the focus of this dissertation. In the …

Caveolin-Mediated Endocytosis: Bacterial Pathogen Exploitation And Host-Pathogen Interaction, Dibyasri Barman, Rishi Drolia

Biological Sciences Faculty Publications

Within mammalian cells, diverse endocytic mechanisms, including phagocytosis, pinocytosis, and receptor-mediated endocytosis, serve as gateways exploited by many bacterial pathogens and toxins. Among these, caveolae-mediated endocytosis is characterized by lipid-rich caveolae and dimeric caveolin proteins. Caveolae are specialized microdomains on cell surfaces that impact cell signaling. Caveolin proteins facilitate the creation of caveolae and have three members in vertebrates: caveolin-1, caveolin-2, and caveolin-3. Many bacterial pathogens hijack caveolin machinery to invade host cells. For example, the Gram-positive facultative model intracellular bacterial pathogen Listeria monocytogenes exploits caveolin-mediated endocytosis for efficient cellular entry, translocation across the intestinal barrier, and cell–cell spread. Caveolin …

Biosorption Of Lithium Using Microbes, Adebola Daisy Olade

Theses (2016-Present)

Lithium (Li) is a very valuable metal that is used across several industries including ceramics, glass, batteries, pharmaceuticals, and polymers. However, in recent years, the global demand for Li and its market price have increased considerably, due to its application as a critical component in the production of rechargeable Li-ion batteries and energy storage systems that are used in electric vehicles and a variety of electronic devices. Although Li occurs as a mineral in hard rocks and salt brines, substantial amounts are found in our environment as part of industrial wastes and oil-field wastewaters. Despite its importance, Li is also …

Inactivation Of Escherichia Coli, Salmonella Enterica, And Listeria Monocytogenes Using The Contamination Sanitization Inspection And Disinfection (Csi-D) Device, Jennifer Mccoy Sanders, Vanessa Alarcon, Grace Marquis, Amanda Tabb, Jo Ann Van Kessel, Jakeitha Sonnier, Brad J. Haley, Insuck Baek, Jianwei Qin, Moon Kim, Fartash Vasefi, Stanislav Sokolov, Rosalee S. Hellberg

Food Science Faculty Articles and Research

The Contamination Sanitization Inspection and Disinfection (CSI-D) device is a handheld fluorescence-based imaging system designed to disinfect food contact surfaces using ultraviolet-C (UVC) illumination. This study aimed to determine the optimal CSI-D parameters (i.e., UVC exposure time and intensity) for the inactivation of the following foodborne bacteria plated on non-selective media: generic Escherichia coli (indicator organism) and the pathogens enterohemorrhagic E. coli, enterotoxigenic E. coli, Salmonella enterica, and Listeria monocytogenes. Each bacterial strain was spread-plated on non-selective agar and exposed to high-intensity (10 mW/cm²) or low-intensity (5 mW/cm²) UVC for 1–5 s. Control …

Trna Anticodon Cleavage By Target-Activated Crispr-Cas13a Effector, Ishita Jain, Matvey Kolesnik, Konstantin Kuznedelov, Leonid Minakhin, Natalia Morozova, Anna Shiriaeva, Alexandr Kirillov, Sofia Medvedeva, Alexei Livenskyi, Laura Kazieva, Kira S Makarova, Eugene V Koonin, Sergei Borukhov, Konstantin Severinov, Ekaterina Semenova

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Type VI CRISPR-Cas systems are among the few CRISPR varieties that target exclusively RNA. The CRISPR RNA–guided, sequence-specific binding of target RNAs, such as phage transcripts, activates the type VI effector, Cas13. Once activated, Cas13 causes collateral RNA cleavage, which induces bacterial cell dormancy, thus protecting the host population from the phage spread. We show here that the principal form of collateral RNA degradation elicited by Leptotrichia shahii Cas13a expressed in Escherichia coli cells is the cleavage of anticodons in a subset of transfer RNAs (tRNAs) with uridine-rich anticodons. This tRNA cleavage is accompanied by inhibition of protein synthesis, thus …

Reiq-Mediated Alarmone Signalling Regulates Growth, Stress-Induced Biofilm Formation And Spore Accumulation In Clostridioides Difficile, Areej Malik, Adenrele Oludiran, Asia Poudel, Orlando Berumen Alvarez, Charles Woodward, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The bacterial stringent response (SR) is a conserved transcriptional reprogramming pathway mediated by the nucleotide signalling alarmones, (pp)pGpp. The SR has been implicated in antibiotic survival in Clostridioides difficile, a biofilm- and spore-forming pathogen that causes resilient, highly recurrent C. difficile infections. The role of the SR in other processes and the effectors by which it regulates C. difficile physiology are unknown. C. difficile RelQ is a clostridial alarmone synthetase. Deletion of relQ dysregulates C. difficile growth in unstressed conditions, affects susceptibility to antibiotic and oxidative stressors and drastically reduces biofilm formation. While wild-type C. difficile displays increased biofilm …

Harnessing Antagonistic Pleiotropy: Tolc-Dependent Coliphages Can Drive Reduced Antibiotic Resistance In E. Coli, Cooper Mckenna

CMC Senior Theses

The rise of multidrug-resistant (MDR) bacterial pathogens has been a growing concern in healthcare around the world, and bacteriophage (phage) therapy is a promising method to combat MDR infections. One defense mechanism of E. coli against antibiotics is the TolC-AcrAB efflux pump. At the same time, some phages use TolC as a surface receptor to infect the cell. This puts TolC at a crossroads in which it is beneficial to the bacteria to protect against antibiotics but harmful by allowing phage infection, creating the potential for evolutionary trade-offs. Previous research has identified only three TolC-dependent phages and shown phage-resistant E. …

Molecular Epidemiology Of Antibiotic Resistance Among Escherichia Coli Isolated From Broiler Chickens Sold At Selected Markets In Dar Es Salaam, Tanzania, Abdilahi H. Kiula, Victor A. Makene

Tanzania Journal of Science

Unwarranted and improper uses of antibiotics in broiler farms contribute to the challenge of antibiotic resistance, making even previously treatable infections, difficult to treat. We conducted a cross sectional study from November 2021 to May 2022 from broiler chicken markets in four districts of Dar es Salaam to determine the extent of antibiotic resistance among E. coli isolates from broiler chickens. A total of 160 E. coli isolates recovered from cloacal swabs were identified by culture and biochemical tests and confirmed by Polymerase Chain Reaction (PCR) assays. Antimicrobial susceptibility testing, targeting seven classes of antibiotics, was performed by disk diffusion …

Renovating A Double Fence With Or Without Notifying The Next Door And Across The Street Neighbors: Why The Biogenic Cytoplasmic Membrane Of Gram-Negative Bacteria Display Asymmetry?, Mikhail Bogdanov

Faculty, Staff and Student Publications

The complex two-membrane organization of the envelope of Gram-negative bacteria imposes an unique biosynthetic and topological constraints that can affect translocation of lipids and proteins synthesized on the cytoplasm facing leaflet of the cytoplasmic (inner) membrane (IM), across the IM and between the IM and outer membrane (OM). Balanced growth of two membranes and continuous loss of phospholipids in the periplasmic leaflet of the IM as metabolic precursors for envelope components and for translocation to the OM requires a constant supply of phospholipids in the IM cytosolic leaflet. At present we have no explanation as to why the biogenic E. …

The “Big Six”: Hidden Emerging Foodborne Bacterial Pathogens, Mona G. Alharbi, Rashad R. Al-Hindi, Ahmed Esmael, Ibrahim A. Alotibi, Sheren A. Azhari, Mazen S. Alseghayer, Addisu D. Teklemariam

Nebraska Center for Virology: Faculty Publications

Non-O157 Shiga toxin-producing Escherichia coli (STEC) are emerging serogroups that often result in diseases ranging from diarrhea to severe hemorrhagic colitis in humans. The most common non-O157 STEC are O26, O45, O103, O111, O121, and O145. These serogroups are known by the name “big six” because they cause severe illness and death in humans and the United States Department of Agriculture declared these serogroups as food contaminants. The lack of fast and efficient diagnostic methods exacerbates the public impact of the disease caused by these serogroups. Numerous outbreaks have been reported globally and most of these outbreaks were caused by …

Qualitative Proteomic And Genomic Analysis Of Klebsiella Pneumoniae Bacteriophage Kaomega, Emilee Carr

Undergraduate Honors Theses

Klebsiella pneumoniae is a Gram-negative Enterobacteriaceae that is a common nosocomial pathogen causing pneumonia, infections in the bloodstream, wound infections, and meningitis. It has developed natural resistance to multiple antibiotics, most notably carbapenems which are often seen as the last line of defense against multi-drug resistant pathogens. Bacteriophages are being investigated as a promising alternative treatment to antibiotics in fighting these resistant pathogens. KaOmega, a Klebsiella pneumoniae bacteriophage, was isolated, sequenced, and annotated to characterize and understand its potential for use in a phage therapy. Characterization included Phyre2 analysis to predict putative protein functions based on structural homology, burst size …

Describing Bacterial Mutagenic Hotspots And Signatures Along With The Factors That Drive Them, Carmen Vallin

UNLV Theses, Dissertations, Professional Papers, and Capstones

In my dissertation work, I investigated bacterial mutagenesis. I asked: where do mutations occur in the bacterial genome? What types of mutations occur? What factors promote or prevent mutations? And lastly, how do the answers to these questions change depending on the bacterial life cycle (When)? I used Bacillus subtilis, a Gram-positive bacterium belonging to the phylum Firmicutes, and Escherichia coli, a Gram-negative bacterium belonging to the phylum Proteobacteria, to answer these questions. B. subtilis and E. coli are model systems that have been used to gain insights into fundamental processes of mutations and evolution for nearly ~8 decades. Here, …

Assessment Of Bacteriological Quality Of Drinking Water In Some Primary And Secondary Schools In Mukalla City-Hadhramout/Yemen, Eidha Ali Bin Hameed, Khaled Saleh Bin Alshikh Bubkr

Hadhramout University Journal of Natural & Applied Sciences

Assessment of faecal contamination and detection enumeration of coliforms and other microorganisms in water is one of the measurements to determine the hygienic quality of water. This study aimed to assess the drinking water in some primary and secondary schools in Mukalla city-Hadhramout/Yemen to estimate the bacterial contamination of drinking water and its safety to the public. The water samples were studied for bacteriological analysis in which was inoculated into culture media using two methods, the presumptive test for the most probable number (MPN) and confirmatory test for bacterial identification. Also, some physiochemical properties of water such as temperature, total …

Prevalence And Multidrug Resistance Pattern Of E. Coli Among Urinary Tract Infection Patients In Tertiary Care Hospital Of Multan, Hubza Ruatt Khan, Mehvish Javeed, Asghar Javed, Nisma Farooq

Journal of Bioresource Management

Urinary Tract Infection is alarming problem worldwide due to the intensity of antimicrobial resistance. Escherichia coli is the most predominant organism in UTI. This study was planned to evaluate demographic parameters, the prevalence of E. coli, and antimicrobial resistance patterns among E. coli isolates from UTI patients in Nishtar Hospital of Multan from January to June 2018. A total of 350 mid-stream urine samples were collected from different patients having age group from 25 to 60 years and processed by standard laboratory procedures. Out of 350 samples, 100 samples were observed as critical bacteremia. Escherichia coli and Klebsiella …

Sensitivity Of Wild-Type And Rifampicin-Resistant O157 And Non-O157 Shiga Toxin-Producing Escherichia Coli To Elevated Hydrostatic Pressure And Lactic Acid In Ground Meat And Meat Homogenate, Abimbola Allison, Aliyar Cyrus Fouladkhah

Agricultural and Environmental Sciences Faculty Research

Various serogroups of Shiga toxin-producing Escherichia coli have been epidemiologically associated with foodborne disease episodes in the United States and around the globe, with E. coli O157: H7 as the dominant serogroup of public health concern. Serogroups other than O157 are currently associated with about 60% of Shiga toxin-producing E. coli related foodborne illness episodes. Current study evaluated sensitivity of the O157 and epidemiologically important non-O157 serogroups of the pathogen to elevated hydrostatic pressure and 1% lactic acid. Pressure intensity of 250 to 650 MPa were applied for 0 to 7 min for inactivation of strain mixtures of …

Incidence Of Antibiotic Resistance And Plasmid Content In Freshwater Beach Sand And Water And Clinical Urinary Tract Infection Escherichia Coli Isolates, Robert F. White

Biology Theses

Antibiotic-resistant (AR) bacteria have been found in environmental ecosystems including beach sand and water, and pose a serious threat to the mitigation of human and animal disease. The presence of antibiotic residues in the environment, fueled by wastewater effluent and agricultural runoff, may produce selective pressure on introduced microbes such as Escherichia coli, leading to the production of AR populations. This study characterized and compared the antibiotic resistance patterns and plasmid content of E. coli isolated from a freshwater beach and clinical urinary tract infection (UTI) samples. A higher level of antibiotic resistance was expected in clinical (UTI) Escherichia coli …

A Mini-Tn5-Derived Transposon With Reportable And Selectable Markers Enables Rapid Generation And Screening Of Insertional Mutants In Gram-Negative Bacteria, Eric S. Nazareno, Bimala Acharya, C. Korsi Dumenyo

Agricultural and Environmental Sciences Faculty Research

We re-engineered a classic tool for mutagenesis and gene expression studies in Gram-negative bacteria. Our modified Tn5-based transposon contains multiple features that allow rapid selection for mutants, direct quantification of gene expression and straightforward cloning of the inactivated gene. The promoter-less gfp-km cassette provides selection and reporter assay depending on the activity of the promoter upstream of the transposon insertion site. The cat gene facilitates positive antibiotic selection for mutants, while the narrow R6Kγ replication origin forces transposition in recipient strains lacking the pir gene and enables cloning of the transposon flanked with the disrupted gene from the chromosome. The …

Histidine-Triad Hydrolases Provide Resistance To Peptide-Nucleotide Antibiotics., Eldar Yagmurov, Darya Tsibulskaya, Alexey Livenskyi, Marina Serebryakova, Yury I Wolf, Sergei Borukhov, Konstantin Severinov, Svetlana Dubiley

Rowan-Virtua School of Osteopathic Medicine Departmental Research

The Escherichia coli microcin C (McC) and related compounds are potent Trojan horse peptide-nucleotide antibiotics. The peptide part facilitates transport into sensitive cells. Inside the cell, the peptide part is degraded by nonspecific peptidases releasing an aspartamide-adenylate containing a phosphoramide bond. This nonhydrolyzable compound inhibits aspartyl-tRNA synthetase. In addition to the efficient export of McC outside the producing cells, special mechanisms have evolved to avoid self-toxicity caused by the degradation of the peptide part inside the producers. Here, we report that histidine-triad (HIT) hydrolases encoded in biosynthetic clusters of some McC homologs or by standalone genes confer resistance to McC-like …

Post-Translational Modifications And Functional Studies Of Dksa In Escherichia Coli, Andrew Charles Isidoridy

Legacy Theses & Dissertations (2009 - 2024)

DksA is a bacterial gene regulator that functions synergistically with the stress alarmone ppGpp to mediate the stringent response. DksA also functions independently of ppGpp to regulate transcription of a number of genes. DksA function is dependent on its binding affinity to RNA polymerase and requires specific interactions between RNAP and catalytic amino acids located on the coiled coil tip, D74 and A76. While much of the previous work on DksA has focused on understanding the mechanisms of action and the numerous gene targets for transcriptional regulation, little is known about the mechanisms by which DksA expression and function may …

Transcriptional Regulation Of Dksa In E. Coli, Daniel Thomas Woods

Legacy Theses & Dissertations (2009 - 2024)

DksA is a global transcription factor that binds RNAP directly to regulate the expression of many genes and operons, including ribosomal RNA, in a ppGpp-dependent or ppGpp–independent manner. It is also involved in facilitating the process of DNA replication by removing stalled transcription elongation complexes that could block the progress of the replication fork. In addition, DksA is important for colonization, establishment of biofilms, and pathogenesis. In order to sustain these various functions, an adequate level of cellular DksA is required. This work tested the hypothesis that the E. coli dksA is substantially regulated at the level of transcription. Using …

Premature Rho-Dependent Transcription Termination In Escherichia Coli : Link To Translation And Gene Regulation, Gabriele Baniulyte

Legacy Theses & Dissertations (2009 - 2024)

Transcription termination factor Rho is an essential protein in Escherichia coli and related bacteria. The primary function of Rho is to clear unproductive RNA polymerases from the DNA template to minimize negative effects associated with uncontrolled transcription. Although most of the Rho termination events are constitutive, premature Rho-mediated termination was observed at 3% of all affected transcripts indicating active regulation of Rho activity. In this work, we investigated the regulatory mechanism behind premature Rho-dependent transcription termination in two unrelated genes: suhB and topAI. We show that in both cases transcription is terminated inside the coding gene as a consequence of …

Regulation Of Acetyl Phosphate-Dependent Acetylation And Identification Of Novel Lysine Acetyltransferases In Escherichia Coli, David George Christensen

Dissertations

Over billions of years, organisms have organized chemical reactions into metabolic pathways to sustain life. However, metabolic substrates can undergo many uncatalyzed, extra-metabolic reactions. Acetyl phosphate (AcP), an intermediate of the acetate fermentation pathway in E. coli, is one such metabolite that has been shown to non-enzymatically acetylate hundreds of proteins. This diverse set of targets suggests that acetylation could be a way for the cell to sense its nutritional status and regulate protein activity accordingly. However, how E. coli regulates acetylation, if at all, is unknown.Previous work showed that acetylation becomes pronounced in stationary phase cells. I determined that …

Investigating The Single Cell Heterogeneity And Physiological Impact Of Mistranslation, Christopher Evans

Dissertations and Theses (Open Access)

Bacterial populations grow clonal populations; however, individual cells have a variety of phenotypes. The physiological heterogeneity observed in populations has been attributed to variations in the processes of gene expression. For example, promoter expression has been shown to be heterogeneous within a population and contribute to increased stress tolerance in a subpopulation of cells. In comparison to transcription, the influence of translation on single cells is unclear. In this study, my collaborators and I have developed a dual-fluorescence reporter that allows us to measure the mistranslation rate in single cells in vivo. Using this reporter, we found that mistranslation …

A Recurrent Silent Mutation Implicates Feca In Ethanol Tolerance By Escherichia Coli., Katherine M Lupino, Kymberleigh A Romano, Matthew J Simons, John T Gregg, Leanna Panepinto, Ghislaine M Cruz, Lauren Grajek, Gregory A. Caputo, Mark J. Hickman, Gregory B. Hecht

College of Science & Mathematics Departmental Research

BACKGROUND: An issue associated with efficient bioethanol production is the fact that the desired product is toxic to the biocatalyst. Among other effects, ethanol has previously been found to influence the membrane of E. coli in a dose-dependent manner and induce changes in the lipid composition of the plasma membrane. We describe here the characterization of a collection of ethanol-tolerant strains derived from the ethanologenic Escherichia coli strain FBR5.

RESULTS: Membrane permeability assays indicate that many of the strains in the collection have alterations in membrane permeability and/or responsiveness of the membrane to environmental changes such as temperature shifts or …