About

Alexander J. Travis, VMD, PhD, is a professor of reproductive biology and the director of the Master of Public Health program at Cornell University’s Baker Institute for Animal Health within the College of Veterinary Medicine. His research focuses on studies of reproduction, wildlife, and public health to create healthier animals and humans. His work explores the interdisciplinary field of One Health, linking the health and wellbeing of people, animals, and the environment. Dr. Travis’s interests include animal and human fertility, efforts to alleviate poverty and hunger in developing countries, and indirect benefits to local wildlife. He has contributed to advancements in assisted reproduction, including the development of a male fertility test called the 'Cap-Score,' which helps diagnose male fertility issues and guides treatment options for couples seeking to conceive. Dr. Travis and his team achieved a significant milestone by successfully producing puppies via in vitro fertilization, marking the first time this technique was accomplished in dogs, with implications for preventing genetic diseases and aiding wildlife conservation efforts. Additionally, he has developed rapid diagnostic devices for stroke and other disorders, capable of delivering results in less than ten minutes using minimal blood samples. His research also includes harnessing sperm tail enzymes to create enzyme machines for energy production, with potential applications in nanobiotechnology and medical devices.

Research topics

• Biology
• Biochemistry
• Cell biology
• Medicine
• Demography
• Chemistry
• Endocrinology
• Gynecology
• Genetics
• Andrology
• Internal medicine
• Obstetrics

Selected publications

• A prodrug strategy for sustained release of lactic acid from silicone elastomer vaginal rings

  International Journal of Pharmaceutics · 2025-08-26 · 1 citations

  articleOpen access

  Lactic acid is the most abundant organic weak acid in the healthy human vagina and plays a pivotal role in maintaining an acidic vaginal environment protective against exogenous bacteria and viruses. However, in dysbiotic or non-optimal vaginal environments, significantly decreased concentrations of lactobacilli result in reduced lactic acid production, increased vaginal pH, and enhanced risk of sexually transmitted infections (including human immunodeficiency virus), and bacterial vaginosis. Various gel-based products are marketed to administer lactic acid vaginally for the treatment of bacterial vaginosis and non-hormonal contraception, and there is interest in developing vaginal ring products for sustained/controlled release of lactic acid. However, lactic acid is not compatible with the most common addition-cure type of silicone elastomer used to manufacture vaginal rings; the carboxylic acid group inhibits the hydrosilylation reaction used to cure the elastomer system. Here, we report that DL-lactide-a racemic mixture of (R,R)-D-lactide and (S,S)-L-lactide, in which the dilactide molecules are cyclic lactones derived from esterification of two molecules of lactic acid-can be successfully incorporated into and released from addition-cure medical grade silicone elastomer vaginal rings. Following release of lactide from the rings into an aqueous medium, the lactide molecule rapidly hydrolyses to produce only lactic acid. We demonstrate that lactic acid (i) is formed f release of lactide from the rings; (ii) inhibits sperm motility, (iii) inhibits replication of HIV-1 and HSV-2, and (iv) is active against Gardnerella vaginalis (one of the causative organisms responsible for bacterial vaginosis) but not lactobacillus (associated with optimal human vaginal health). The results support the inclusion of lactide as a lactic acid prodrug in next-generation multipurpose contraceptive silicone elastomer vaginal rings.

  PublisherDOI

• In vitro exposure to epididymal extracellular vesicles from normospermic domestic cats improves developmental potential of sperm from teratospermic cats

  Frontiers in Veterinary Science · 2025-01-17

  articleOpen access

  We have previously reported a difference in the composition of epididymal extracellular vesicles (EVs) between normospermic and teratospermic domestic cats. The objective of the present study was to investigate whether the fertilizing ability or developmental potential of sperm from teratospermic cats could be improved after incubation with EVs isolated from normospermic cats. For each of 11 experimental replicates, pools of EVs were collected from the whole epididymides of 5 normospermic cats (normospermic EVs). Spermatozoa were also collected from the cauda epididymides of 2 teratospermic cats, pooled, and half was co-incubated with normospermic EVs for 1 h and 15 min prior to using the sperm for in vitro fertilization (IVF). The other half of the sperm was kept for 1 h and 15 min in the absence of EVs as a control group. We found no difference ( p > 0.05) in sperm fertilizing ability, based on the percentage of cleaved embryos, after incubation with EVs (67.0%) and without EVs (60.6%). However, the developmental potential of teratospermic sperm, based on the proportion of embryos that reached the 8-cell stage or further, was better ( p < 0.05) after co-incubation with EVs (58.4%) compared to the control group without EVs (47.2%). Additionally, the proportion of embryos that reached the blastocyst stage was better ( p < 0.05) after co-incubation with EVs (30.7%) compared to the control group without EVs (19.9%). These findings can be used to improve the outcome of IVF with teratospermic males in domestic or wild felid species.

  PublisherDOI

• Extracellular vesicles are involved in the paracrine communication between epithelial cells in different regions of the domestic cat epididymis

  Biology of Reproduction · 2024-08-27

  articleOpen access

  Sperm maturation depends on exposure to microenvironments within the different segments of the epididymis, but mechanisms underlying how these microenvironments are produced or maintained are not well understood. We hypothesized that epididymal extracellular vesicles could play a role in the process of maintaining microenvironments in different regions of the epididymis. Specifically, we tested whether the extracellular vesicles from different regions of the epididymis can ensure paracrine communication between cells in different segments. Domestic cat tissues were used to develop a reproducible in vitro culture system for corpus epididymis explants that were then exposed to extracellular vesicles collected from upstream (i.e., caput) segments. Impacts of different culture or exposure conditions were compared by analyzing the morphology, apoptosis, transcriptional activity, and gene expression in the explants. Here, we report the development of the first in vitro culture system for epididymal tissue explants in the domestic cat model. Using this system, we found that extracellular vesicles from the caput segment have a significant effect on the transcriptional profile of tissue from the corpus segment (1233 differentially expressed genes due to extracellular vesicle supplementation). Of note, expressions of genes associated with regulation of epithelial cell differentiation and cytokine signaling in the epididymis were influenced by the presence of extracellular vesicles. Together, our findings comprise the first report in any species of paracrine control of segmental gene regulation by epididymal extracellular vesicles. These results contribute to a better understanding of epididymis biology and could lead to strategies to enhance or suppress male fertility.

  PublisherOA PDFDOI

• MEN WITH LOW CAP-SCORES HAVE IVF/ICSI OUTCOMES THAT ARE AS GOOD AS MEN WITH NORMAL SCORES

  Fertility and Sterility · 2024-10-01

  articleSenior author
  PublisherDOI

• Real-Time Imaging of Calcium Dynamics in Human Sperm After Precise Single-Cell Stimulation

  Methods in molecular biology · 2024-10-12

  articleSenior author
  PublisherDOI

• JoVE Video Dataset

  2023-10-14

  articleSenior author

  Acrosome exocytosis (AE), in which the sperm's single exocytotic vesicle fuses with the plasma membrane, is a complex, calcium-dependent process essential for fertilization. However, our understanding of how calcium signaling regulates AE is still incomplete. In particular, the interplay between intra-acrosomal calcium dynamics and the intermediate steps leading to AE is not well-defined. Here, we describe a method that provides spatial and temporal insights into acrosomal calcium dynamics and their relationship to membrane fusion and subsequent exocytosis of the acrosome vesicle. The method utilizes a novel transgenic mouse expressing an Acrosome-targeted Sensor for Exocytosis (AcroSensE). The sensor combines a genetically encoded calcium indicator (GCaMP) fused with mCherry. This fusion protein was specifically designed to enable the concurrent observation of acrosomal calcium dynamics and membrane fusion events. Real-time monitoring of acrosomal calcium dynamics and AE in live AcroSensE sperm is achieved using a combination of high frame-rate imaging and a stimulant delivery system that can target single sperm. This protocol also provides several examples of basic methods to quantify and analyze the raw data. Because the AcroSensE model is genetically encoded, its scientific significance can be augmented by using readily available genetic tools, such as crossbreeding with other mouse genetic models or gene-editing (CRISPR) based methods. With this strategy, the roles of additional signaling pathways in sperm capacitation and fertilization can be resolved. In summary, the method described here provides a convenient and effective tool to study calcium dynamics in a specific subcellular compartment-the sperm acrosome-and how those dynamics regulate the intermediate steps leading to membrane fusion and acrosome exocytosis.

  PublisherDOI

• Abstract TMP45: Nanobiotechnology-based, Ultra-rapid Test For Brain Injuries To Accelerate Differential Diagnosis Of Stroke From Mimics

  Stroke · 2023-02-01

  articleSenior author

  Introduction: Stroke is the 5th leading cause of death, and a leading cause of long-term disability in the US. Thus, there is a need for a rapid biomarker-based screen that enables an objective and timely diagnosis and better patient outcome; however, the lack of such a technology delays diagnosis and treatment, increases misdiagnosis, and leads to the overuse of thrombolysis in patients with stroke mimics. Methods: Here we present pilot data of a nanobiotechnology based test platform, in which enzyme-functionalized nanoparticles (TET, Tethered Enzyme Technology) are used for ultra-rapid biomarker detection. As proof of concept, we used TET to quantify the enzymatic activity of a widely studied brain injury biomarker, neuron-specific enolase (NSE), in a trial performed at a regional stroke center. Results: Plasma from 36 suspected stroke and 17 asymptomatic subjects (Total N=53) was tested to determine levels of the novel biomarker NSE catalytic activity (NSE-A) versus the conventional NSE protein (NSE-P). Based on clinical diagnoses, our data demonstrate a significant increase in the levels of NSE-A in subjects suffering from injury to neurons (BI, Brain Injury) compared to those with negative diagnoses (Neg, stroke mimics). Moreover, we show that NSE-A provides a considerable diagnostic advantage over the NIH Stroke Scale or NSE-P (Figure 1A-C) in both clinical utility and speed. In diagnosis of stroke mimics (including TIAs and Neg) versus BI, NSE-A showed significantly better performance than NIHSS or NSE-P, as shown by ROC and AUC analyses (Figure 1D). Conclusions: TET-based detection of NSE-A can rapidly differentiate patients suffering a neuronal injury, including stroke, from those presenting with stroke mimics. Upon further development of a point-of-care test for NSE-A and other biomarkers, TET could be an asset to ongoing efforts to streamline stroke patient care, reduce door to needle time, and decrease overall brain injury and long-term disability.

  PublisherDOI

• Facilitated Asynchronous Online Learning to Build Public Health Strategic Skills

  Journal of Public Health Management and Practice · 2023-08-29 · 7 citations

  articleOpen accessSenior author

  CONTEXT: The COVID-19 pandemic spurred significant government investments for hiring public health workers. There are clear opportunities to help build capacities among both current and incoming public health workers, closing well-elucidated skill gaps. OBJECTIVE: To report on the development process, methods used, and outcomes seen from a point-in-time public health workforce capacity-building initiative, Public Health Essentials (PHE) . DESIGN: Capacity-building outcomes evaluation using pre/postintervention measures. SETTING: The United States. PARTICIPANTS: A total of 512 learners working in roles (government or adjacent to) that support public health. INTERVENTION: PHE, a cohort-based facilitated asynchronous online course comprising 5 units, 18 modules, 54 learning outcomes, and 266 teaching and applied assessment elements designed to build public health strategic skills. MAIN OUTCOME MEASURES: Two outputs and 3 outcomes were used to assess and improve progress in achieving our goal of building generalizable and transferrable public health ability and confidence among diverse public health workers: Use of PHE , PHE completion rate , Learner competence , Change in self-assessed ability , and Benefits of PHE. RESULTS: From September 2021 to December 2022, 4 agencies used PHE for fellowship training or employee capacity building. Some 79% (n = 512) of learners completed the training, demonstrating competence in all 54 areas assessed by expert course facilitators. Of those, 79% (n = 321) completed both optional pre- and post-PHE surveys, reporting statistically significant gains in all strategic skill domains assessed (n = 9), regardless of demographics and public health experience. Learners gained new skills and knowledge (92%), developed a better understanding of public health (86%), and broadened their public health skill base (84%). A majority can apply the knowledge and skills gained directly to their work (94%), which benefits their team (92%), and have increased their confidence as public health practitioners (49%). CONCLUSIONS: PHE can significantly improve learners' ability across 9 strategic skill areas in as few as 15 weeks, regardless of their demographics, training, or experience.

  PublisherDOI

• Real-Time Imaging of Acrosomal Calcium Dynamics and Exocytosis in Live Mouse Sperm

  Journal of Visualized Experiments · 2023-10-13 · 3 citations

  articleSenior author

  Acrosome exocytosis (AE), in which the sperm's single exocytotic vesicle fuses with the plasma membrane, is a complex, calcium-dependent process essential for fertilization. However, our understanding of how calcium signaling regulates AE is still incomplete. In particular, the interplay between intra-acrosomal calcium dynamics and the intermediate steps leading to AE is not well-defined. Here, we describe a method that provides spatial and temporal insights into acrosomal calcium dynamics and their relationship to membrane fusion and subsequent exocytosis of the acrosome vesicle. The method utilizes a novel transgenic mouse expressing an Acrosome-targeted Sensor for Exocytosis (AcroSensE). The sensor combines a genetically encoded calcium indicator (GCaMP) fused with mCherry. This fusion protein was specifically designed to enable the concurrent observation of acrosomal calcium dynamics and membrane fusion events. Real-time monitoring of acrosomal calcium dynamics and AE in live AcroSensE sperm is achieved using a combination of high frame-rate imaging and a stimulant delivery system that can target single sperm. This protocol also provides several examples of basic methods to quantify and analyze the raw data. Because the AcroSensE model is genetically encoded, its scientific significance can be augmented by using readily available genetic tools, such as crossbreeding with other mouse genetic models or gene-editing (CRISPR) based methods. With this strategy, the roles of additional signaling pathways in sperm capacitation and fertilization can be resolved. In summary, the method described here provides a convenient and effective tool to study calcium dynamics in a specific subcellular compartment-the sperm acrosome-and how those dynamics regulate the intermediate steps leading to membrane fusion and acrosome exocytosis.

  PublisherDOI

• Segmental differentiation of the murine epididymis: identification of segment-specific, GM1-enriched vesicles and regulation by luminal fluid factors

  Biology of Reproduction · 2023-09-11 · 10 citations

  articleOpen accessSenior author

  The murine epididymis has 10 distinct segments that provide the opportunity to identify compartmentalized cell physiological mechanisms underlying sperm maturation. However, despite the essential role of the epididymis in reproduction, remarkably little is known about segment-specific functions of this organ. Here, we investigate the dramatic segmental localization of the ganglioside GM1, a glycosphingolipid already known to play key roles in sperm capacitation and acrosome exocytosis. Frozen tissue sections of epididymides from adult mice were treated with the binding subunit of cholera toxin conjugated to AlexaFluor 488 to label GM1. We report that GM1-enriched vesicles were found exclusively in principal and clear cells of segment 2. These vesicles were also restricted to the lumen of segment 2 and did not appear to flow with the sperm into segment 3, within the limits of detection by confocal microscopy. Interestingly, this segment-specific presence was altered in several azoospermic mouse models and in wild-type mice after efferent duct ligation. These findings indicate that a lumicrine factor, itself dependent on spermatogenesis, controls this segmental differentiation. The RNA sequencing results confirmed global de-differentiation of the proximal epididymal segments in response to efferent duct ligation. Additionally, GM1 localization on the surface of the sperm head increased as sperm transit through segment 2 and have contact with the GM1-enriched vesicles. This is the first report of segment-specific vesicles and their role in enriching sperm with GM1, a glycosphingolipid known to be critical for sperm function, providing key insights into the segment-specific physiology and function of the epididymis.

  PublisherOA PDFDOI

Recent grants

• Nanoscale energy production for implantable medical devices

  NIH · $2.3M · 2009–2014

• Membrane lipid regulation of calcium channels in sperm.

  NIH · $2.1M · 2019–2025

• NIH Grant K01RR000188

  NIH · $589k · 2005

• Nanoscale energy production for implantable medical devices

  NIH · $1.5M · 2009–2015

• NIH Grant R01HD045664

  NIH · $1.3M · 2009

Frequent coauthors

• Jacquelyn L. Nelson

  Cornell University

  52 shared

• Atsushi Asano

  Kagoshima University

  43 shared

• Jennifer B. Nagashima

  33 shared

• Roy Cohen

  New York State College of Veterinary Medicine

  27 shared

• Chinatsu Mukai

  Cornell University

  27 shared

• Sarah E. Dumas

  New York City Department of Health and Mental Hygiene

  27 shared

• Chris T. Darimont

  Raincoast Conservation Foundation

  25 shared

• Bonnie L. Keeler

  University of Minnesota

  25 shared

Labs

• Baker Institute for Animal HealthPI