Biology subjects

Kozik, A. J.

Publications and source records attributed to Kozik, A. J..

7 recordsLinked to original sources

bioRxiv2026

Phenotypic characterization of Prevotella melaninogenica ATCC 25845

Prevotella melaninogenica is a Gram-negative bacterium that has been implicated in numerous disorders such as chronic obstructive pulmonary disease (COPD) and cystic fibrosis, and despite its abundance in the human microbiome, there is still limited knowledge on the fundamental physiology describing Prevotella melaninogenica. To properly advance Prevotella biology, it is critical to report and document such characterizations of Prevotella; therefore, the purpose of this study is to examine and define the phenotypic and growth characteristics of P. melaninogenica ATCC 25845. In this study, we found that Prevotella melaninogenica ATCC 25845 is a Gram-negative bacterium that is predominantly short and medium rod-shaped, with occasional filamentous rods. SEM imaging revealed that this filamentation may serve as division centers, points from which multiple daughter cells form. We also describe the antibiotic profile, which showed susceptibility to four classes and resistance to six classes of antibiotics. Carbon source growth kinetic characterization revealed a preference for carbohydrate sources.

microbiology↗

bioRxiv2026

When are Biomedical Postdocs Ready for the Faculty Job Market? A Mixed-Methods Analysis of Metrics and Resilience Among Faculty Job Seekers

PurposeDiscussions surrounding the biomedical faculty job market often focus on applicant competitiveness and external metrics such as number of publications and funding records. Consequently, there is typically less discussion about applicant readiness, the point at which applicants perceive themselves as prepared to enter the market. Since 2018 our group, the Faculty Job Market Collaboration (FJMC), has conducted annual end-of-cycle surveys of biomedical faculty job applicants, producing the largest longitudinal dataset on this process to date. MethodsWe employed a mixed-methods design examining faculty applicants in biological science fields in North America. Regression analyses were conducted on a longitudinal dataset of 729 respondents across multiple hiring cycles. To determine how applicants evaluated their own preparation, qualitative interviews were conducted with a separate cohort of biomedical postdoctoral applicants during the 2024-2026 job cycles. ResultsOur findings demonstrate that rather than depending on a single quantitative threshold, readiness is a multifaceted construct shaped by actionable and interpersonal drivers. Key factors influencing an applicants perceived readiness include taking agency to submit applications, receiving explicit support from a mentor, incorporating strategic use of artificial intelligence tools into application preparation, and their career stage. ConclusionBy distinguishing individual readiness from systemic assumptions of market competitiveness, this study highlights a blind spot in academic workforce development. Our results suggest that applicants can achieve readiness and successful outcomes through different combinations of support, strategy, and timing rather than a uniform metric profile. By integrating quantitative and qualitative data, our study provides an evidence-based framework for understanding applicant readiness and offers practical guidance to help trainees navigate the increasingly competitive academic job market. Teaser TextOur mixed-model analysis of the biomedical faculty job market is designed to help prospective faculty candidates assess their readiness to enter the job market. By integrating multiple indicators of academic productivity, funding success, and professional experience, our study provides evidence-based benchmarks that can guide applicants in evaluating their competitiveness and identifying areas for further development before pursuing faculty positions.

scientific communication and education↗

bioRxiv2026

Aerotolerant Capacity of the Lung Commensal Prevotella melaninogenica

Prevotella melaninogenica is a core member of the human oral and respiratory microbiomes, often representing more than 10% of microbial populations in both healthy and diseased lungs. Despite its prevalence in these oxygenated environments, P. melaninogenica has been historically classified as a strict obligate anaerobe, ostensibly unable to survive oxygen concentrations exceeding 0.05%. This creates a fundamental biological paradox, as the organism consistently persists in the lower respiratory tract where oxygen levels reach higher than what is tolerated by obligate anaerobes. In this study, we resolve this contradiction by evaluating the growth and tolerance of P. melaninogenica across intermediate oxygen concentrations of 2%, 5%, and 8%. Contrary to the long-standing classification, we demonstrate that P. melaninogenica maintains growth at 2% and 5% oxygen- a level significantly higher than previously reported for the genus- and exhibits robust aerotolerance in 21% O2. Transcriptional profiling via RNA-sequencing reveals that this survival is likely driven by the robust expression of oxidative stress defense and DNA repair machinery. Ultimately, these results provide the first evidence of the specialized mechanisms that enable Prevotella melaninogenica to adapt to and colonize the respiratory tract, providing a clearer understanding of its persistence in oxygen-exposed human niches. IMPORTANCEThis study provides a correction to the 100-year-old classification of Prevotella melaninogenica as a strict obligate anaerobe. We demonstrate that this key member of the human microbiome is capable of robust growth under oxygen levels previously thought to be lethal. By identifying transcriptional responses associated with growth and survival, we predict how Prevotella melaninogenica dominates the oxygenated niches of the respiratory tract. This work reveals the putative mechanisms driving the adaptive evolution of Prevotella melaninogenica and its role in human airway ecology.

microbiology↗

bioRxiv2025

Development of a basal media for carbon utilization assay and analysis of the starch utilization locus in Prevotella melaninogenica

Prevotella melaninogenica is a highly abundant member of the human respiratory microbiota, occupying a range of distinct niches from the oral cavity to the lower airways. Colonization within these nutrient diverse environments suggest a sophisticated metabolic system equipped to deal with large fluctuations in nutrient availability. However, the core physiology and metabolic profile of this bacteria remain largely uncharacterized. In this study, we developed a basal media conducive to assaying carbon utilization of P. melaninogenica and demonstrate the utilization of dietary carbohydrates with varied glycosidic bonds, including the starch mimic cyclodextrin. Furthermore, we identified the putative starch utilization system, highlighting the presence of three novel components which are absent from starch metabolism in the closely related Bacteroides genus. Together, these findings provide the first characterization of the nutritional profile and central metabolic capacity of P. melaninogenica, offering crucial insight into how this bacterium adapts to and thrives within ecologically distinct niches. IMPORTANCEThis work significantly advances our understanding of the metabolic capabilities of Prevotella melaninogenica, a common yet largely unexplored member of the respiratory microbiota. By mapping key aspects of its predicted starch utilization locus, we lay the foundation for future studies on microbial adaptation and persistence in the respiratory tract.

microbiology↗

bioRxiv2024

An updated and expanded characterization of the biological sciences academic job market

In the biological sciences, many areas of uncertainty exist regarding the factors that contribute to success within the faculty job market. Earlier work from our group reported that beyond certain thresholds, academic and career metrics like the number of publications, fellowships or career transition awards, and years of experience did not separate applicants who received job offers from those who did not. Questions still exist regarding how academic and professional achievements influence job offers and if candidate demographics differentially influence outcomes. To continue addressing these gaps, we initiated surveys collecting data from faculty applicants in the biological sciences field for three hiring cycles in North America (Fall 2019 to the end of May 2022), a total of 449 respondents were included in our analysis. These responses highlight the interplay between various scholarly metrics, extensive demographic information, and hiring outcomes, and for the first time, allowed us to look at persons historically excluded due to ethnicity or race (PEER) status in the context of the faculty job market. Between 2019 and 2022, we found that the number of applications submitted, position seniority, and identifying as a women or transgender were positively correlated with a faculty job offer. Applicant age, residence, first generation status, and number of postdocs, however, were negatively correlated with receiving a faculty job offer. Our data are consistent with other surveys that also highlight the influence of achievements and other factors in hiring processes. Providing baseline comparative data for job seekers can support their informed decision-making in the market and is a first step towards demystifying the faculty job market.

scientific communication and education↗

bioRxiv2022

The U.S. academic job market survives the SARS-CoV-2 global pandemic

PurposeThis paper aims to identify the extent to which the COVID-19 pandemic disrupted the academic job market and the ways in which faculty job applicants altered their applications in response to a changing academia. Design/methodology/approachThe data presented here is the portion relevant to COVID-19 collected in a survey of faculty job applicants at the end of the 2019-2020 job cycle in North America (spring 2020). An additional "mid-pandemic" survey was used in fall 2020 for applicants participating in the following job search cycle to inquire about how they were adapting their application materials. A portion of data from the 2020-2022 job cycle surveys was used to represent the "late-pandemic". Job posting data from the Higher Education Recruitment Consortium (HERC) is also used to study job availability. FindingsExamination of faculty job postings from 2018 through 2022 found that while they decreased in 2020, the market recovered in 2021 and beyond. While the market recovered, approximately 10% of the faculty job offers reported by 2019-20 survey respondents were rescinded. Respondents also reported altering their application documents in response to the pandemic as well as delaying or even abandoning their faculty job search. OriginalityThis paper provides a longitudinal perspective with quantitative data on how the academic job market changed through the major events of the COVID-19 pandemic in North America, a subject of intense discussion and stress, particularly amongst early career researchers.

scientific communication and education↗

bioRxiv2019

Insights from a survey-based analysis of the academic job market

Applying for a faculty position is a critical phase of many postdoctoral careers, but most postdoctoral researchers in STEM fields enter the academic job market with little knowledge of the process and expectations. A lack of data has made it difficult for applicants to assess their qualifications relative to the general applicant pool and for institutions to develop effective hiring policies. We analyzed responses to a survey of faculty job applicants between May 2018 and May 2019. We establish various background scholarly metrics for a typical faculty applicant and present an analysis of the interplay between those metrics and hiring outcomes. Traditional benchmarks of a positive research track record above a certain threshold of qualifications were unable to completely differentiate applicants with and without offers. Our findings suggest that there is no single clear path to a faculty job offer and that metrics such as career transition awards and publications in high impact factor journals were neither necessary nor sufficient for landing a faculty position. The applicants perceived the process as unnecessarily stressful, time-consuming, and largely lacking in feedback, irrespective of a successful outcome. Our findings emphasize the need to improve the transparency of the faculty job application process. In addition, we hope these and future data will help empower trainees to enter the academic job market with clearer expectations and improved confidence.

scientific communication and education↗