School of Biological Sciences

Georgia Tech and the College of Sciences community sends its condolences to the family and friends of James (Jim) Reedy, a former professor and chair of the College's former Department of Health & Physical Education. His family held a memorial service on October 23 in Atlanta, Georgia.

Philip Sparling, professor emeritus in the School of Biological Sciences, shared the following message in honor of Reedy:

“Dr. Jim Reedy, a longtime department chair at Georgia Tech, passed away on October 4th at age 85. Recruited in 1978, he led major changes in his unit’s mission and curriculum that included an expansion from physical training classes to courses in lifetime fitness, human anatomy, exercise physiology, and biomechanics. He provided resources to new faculty to develop research programs and transformed the Department of Physical Education & Recreation into the Department of Health & Performance Sciences, a unit within the College of Sciences (today as part of the School of Biological Sciences). He served as chair for 20 years under four different deans (1978-1998). He retired in 2000. Dr. Reedy was a charismatic, passionate, and gifted administrator who had a lasting impact on the GT community.”

James Reedy obituary

James Alan Reedy, beloved husband, father, grandfather and friend passed away peacefully on October 4, 2023, in Atlanta, Georgia. He was 85 years old. Born in Clintwood, Virginia, he was preceded in death by his parents Corbett and Lelia Reedy, loving wife Kay Reedy and sister Nancy Olson. He is survived by his children Jody Reedy Andrade (Billy), Betsy Reedy Sawyer (Ryan), Bryan Dunlap (Kelley), Bo Dunlap (Jill), and Greg Kershner (Leigh). Jim was a proud grandfather to his fourteen grandchildren: Cameron, Grace, Tyler, Eli, Sidney, Paige, Grant, Jackson, Meredith, Eliza, Isabella, Sechaba, Talia and Meti.

Jim was a graduate of John Marshall High School in Richmond, Virginia and Bridgewater College where he resides in the Hall of Fame for men’s basketball. He earned a master’s degree from Long Beach State and doctorate degree from Vanderbilt University.

Jim had a strong Christian faith grounded from his youth and his parental teachings. This led to a work ethic that was admired for its integrity and dedication to the field of health and physical education. A life-long educator, he served in many roles including teacher, coach, athletic director and college administrator. He began his career at Bridgewater College and finished at Georgia Tech as department head and professor of the Health and Performance Sciences Department. His influence upon those with whom he taught and mentored lingers to this day.

Jim enjoyed daily exercise, delicious food, a good old movie, anything sports related and especially time with family. He had a gift for storytelling and could captivate an audience with his humorous tales and poems. Over the past several years, he began to write novels and had several published that relied on the connections he had with people throughout his life. He chose joy daily and his encouraging spirit will be forever missed.

When you just can’t find anyone to hang out with on a Friday night, it might not be a comfort to know that bacteria may have you beat when it comes to a social life.

“We now know that bacteria can lead complex social lives, communicating and cooperating within multicellular groups,” says Sam Brown, professor in the School of Biological Sciences and a member/past director of Georgia Tech’s Center for Microbial Dynamics and Infection (CMDI).

Getting out and about in the microbial world leaves bacteria facing challenges such as competition from other bacteria, threats from bacteria-eating viruses, drugs that target them, and starvation when they can’t find a host organism. Brown and his fellow CMDI scientists now want to know how bacteria modify their behaviors in response to their social and physical environments.

Two new grants totaling nearly $1.5 million will give them that chance.

One of the grants, a National Science Foundation award, focuses on how bacteria use clustered regularly interspaced short palindromic repeats — better known as CRISPR, a cellular immune system that helps bacteria ward off threats. CRISPR is perhaps best known as a gene editing tool.

The NSF grant also includes Rachel Kuske, professor in the School of Mathematics and a CMDI member, and Edze Westra, Professor of Microbiology at the University of Exeter in the United Kingdom. The NSF is partnering with the UK’s Biotechnology and Biological Sciences Research Council (BBSRC) for this grant.

The other grant from the Army Research Office (ARO) will study quorum sensing, a form of cell-to-cell communication, to determine how bacteria use it to “count” cells so that collective behavior can be turned on.

Both grants can help CMDI understand microbial behavior in ways that could eventually lead to manipulating or controlling bacteria, says Steve Diggle, CMDI director and a professor in the School of Biological Sciences.

“We are delighted by these new grants as they align closely with the core mission of CDMI because they will advance our understanding of microbial interactions, behaviors, and community dynamics,” Diggle says. “The knowledge generated could have transformative impacts on both academic research and practical applications.”

CRISPR protections, but only in a crowd

Brown wants to make it clear that he and his colleagues won’t be doing any CRISPR gene editing themselves. “Our questions are more basic, focused on how the ‘inventors’ of CRISPR, bacteria, use this system to protect themselves from infection by phages (viruses that attack bacteria) and other molecular parasites of cells,” Brown says.

CRISPR’s role is to recognize and cut out specific sequences of foreign DNA within bacteria. Yet what Brown calls the “dirty secret” of microbiology is that lab bacteria rarely use CRISPR to deal with novel viruses.

“Instead, they use the simple trick of deleting the surface receptors that the virus uses to gain entry to the cell,” he explains. Previous work by CMDI Early Career Award Fellow Ellinor Alseth found an answer to this puzzle: bacteria are more likely to use CRISPR as an immune mechanism when they are living in a multi-species community. What Brown hopes to decipher are the molecular and ecological mechanisms that determine how life in a community can activate CRISPR functions.

“We further aim to build mathematical models of community dynamics, capturing both species interactions and evolutionary changes in a focal species undergoing viral attack,” Brown says. “This will have applied significance by helping the design of more robust microbial communities.”

Quorum sensing = a bacterial census

Regarding the ARO grant, Brown says the standard view for quorum sensing is that bacteria use those signals as a way of counting cells. When the extracellular signal is above a certain threshold, the population is “quorate” (that is, reaches a certain number of cells), and collective behaviors can be turned on.

Yet an increasing body of theory, along with experiments in Brown’s lab and others, has challenged this view “by highlighting that quorum sensing behaviors can also be shaped by the physical environment, such as diffusion, flow rate, and containment,” he says.

Also, behaviors are not “turned on” in a threshold manner with increasing density. “In a high density ‘quorate’ environment, not all cells are expressing canonical quorum sensing-controlled behaviors. These challenges leave us with limited understanding of the functional roles of QS.”

“By examining the balance between intracellular mechanisms and multicellular behaviors, we will obtain a more comprehensive understanding of how bacteria collaborate and respond collectively to their environment,” Diggle adds.

Five Ph.D. scholars from the College of Sciences are the newest members of the Georgia Tech University Center of Exemplary Mentoring (UCEM) Ph.D. Fellowship program, which now includes the College’s Center for Promoting Inclusion and Equity in the Sciences (C-PIES).

“This is the first year the College of Sciences has been involved with UCEM, and it will be very impactful for the professional development for these students,” says Lewis Wheaton, C-PIES director and professor in the School of Biological Sciences. “The process for selection was highly competitive and these students really demonstrate strong scientific ability, have compelling research, and are having a powerful impact in the college community and beyond.”

The new UCEM/C-PIES Fellows:

The Georgia Tech UCEM Ph.D. Fellowship program has the goal of increasing the number of outstanding engineering, science, and computing Ph.D. students from underserved populations. The program seeks to support students from backgrounds that include African American/Black, Hispanic, Native American, and Pacific Islander. The Georgia Tech UCEM Ph.D. Fellowship provides three years of support for students who have recently completed the Ph.D. Qualifying/Preliminary exam.

C-PIES at the College of Sciences works in collaboration with the College of Engineering and the College of Computing — through the Georgia Tech Underrepresented Minority (URM) Graduate Leadership Initiative — to support the Expand Access focus area of the Institute’s strategic plan for graduate student enrollment and retention.

Meet the College of Sciences UCEM Fellows

Sarah E. Gonzalez

“I was excited and relieved to find out I was a UCEM Fellow. As everyone knows, being a grad student isn’t the most financially stable position, so anything extra is a big help,” Gonzales says.

Gonzalez researches in the lab of Associate Professor Elisabetta Matsumoto, studying knitted fabrics and their mechanical behavior. “She is my biggest supporter at Georgia Tech. We have a very tight-knit and supportive research group.”

Danielle Grau

“I was shocked and elated when I received the email with the news, and excited about the opportunity to be a part of such a prestigious fellowship,” Grau says. “I am excited to see what opportunities and relationships it will forge in the future.”

Assistant Professor Alexander Robel is Grau’s thesis adviser. “I am extremely grateful and appreciative for all the support, guidance, and encouragement he has given me throughout my time at Georgia Tech. He's a phenomenal mentor and advisor, and I wouldn’t have had any success without him.”

Sierra A. Knavel

“I was enthusiastic to hear about receiving the award,” Knavel says, “and eager to join a community that wants to help each other succeed while at Georgia Tech.”

Knavel, whose research interests include low-dimensional topology, has Professor John Etnyre as an adviser. “He is the reason I can say I'm in the math Ph.D. program, and that I know I belong here.”

Tony Lemos

“When I applied to the UCEM fellowship, I had doubts that I was accomplished enough to be chosen for this fellowship,” Lemos says. “When I received the email announcing that I had been selected for this award, it was a great surprise, and I was immediately filled with immense gratitude. I am very thankful to be one of the students to receive this gift that will help me become the first in my family to obtain a doctoral degree.”

Lemos is a research assistant in the biophysics lab of Professor Harold Kim, who is his adviser. “He has been a great mentor who helped me get this far at Georgia Tech. He is a great role model that showed me what it means to be an effective scientist. He also challenged me to grow in areas I was uncomfortable with in the lab. I am thankful for his mentorship and unending support.”

Autumn Peterson

“I was super excited to hear that I was named a UCEM Ph.D. Fellow,” Peterson says. “Mentorship has always been important to me. I would not be in the position I am in now without mentors who have supported me throughout my academic career. I am looking forward to strengthening my mentorship skills and serving as a role model for aspiring scientists coming from underrepresented backgrounds like I do.”

Peterson’s adviser is Associate Professor William Ratcliff, who is also Co-Director of the Interdisciplinary Ph.D. in Quantitative Biosciences. ‘I want to thank him for his immense support throughout my academic journey. I would also like to thank Anthony Burnetti, a senior research scientist in the Ratcliff lab. Both Ratcliff and Burnetti are both extremely supportive, kind, and knowledgeable, and I am grateful to have them as mentors.”

Earlier this year, Peterson and Ratcliff were co-awarded a Howard Hughes Medical Institute (HHMI) Gilliam Fellowship for Advanced Study.

“We are so proud of our UCEM/C-PIES Fellows," says Lea Marzo, C-PIES Program Operations Director. "The students selected for this fellowship are brilliant researchers and we are delighted that Georgia Tech’s Office of the President is making an investment in their success. We cannot wait to see what the future has in store for these fellows."

Five Ph.D. scholars from the College of Sciences are the newest members of the Georgia Tech University Center of Exemplary Mentoring (UCEM) Ph.D. Fellowship program, which now includes the College’s Center for Promoting Inclusion and Equity in the Sciences (C-PIES).

“This is the first year the College of Sciences has been involved with UCEM, and it will be very impactful for the professional development for these students,” says Lewis Wheaton, C-PIES director and professor in the School of Biological Sciences. “The process for selection was highly competitive and these students really demonstrate strong scientific ability, have compelling research, and are having a powerful impact in the college community and beyond.”

The new UCEM/C-PIES Fellows:

The Georgia Tech UCEM Ph.D. Fellowship program has the goal of increasing the number of outstanding engineering, science, and computing Ph.D. students from underserved populations. The program seeks to support students from backgrounds that include African American/Black, Hispanic, Native American, and Pacific Islander. The Georgia Tech UCEM Ph.D. Fellowship provides three years of support for students who have recently completed the Ph.D. Qualifying/Preliminary exam.

C-PIES at the College of Sciences works in collaboration with the College of Engineering and the College of Computing — through the Georgia Tech Underrepresented Minority (URM) Graduate Leadership Initiative — to support the Expand Access focus area of the Institute’s strategic plan for graduate student enrollment and retention.

Meet the College of Sciences UCEM Fellows

Sarah E. Gonzalez

“I was excited and relieved to find out I was a UCEM Fellow. As everyone knows, being a grad student isn’t the most financially stable position, so anything extra is a big help,” Gonzales says.

Gonzalez researches in the lab of Associate Professor Elisabetta Matsumoto, studying knitted fabrics and their mechanical behavior. “She is my biggest supporter at Georgia Tech. We have a very tight-knit and supportive research group.”

Danielle Grau

“I was shocked and elated when I received the email with the news, and excited about the opportunity to be a part of such a prestigious fellowship,” Grau says. “I am excited to see what opportunities and relationships it will forge in the future.”

Assistant Professor Alexander Robel is Grau’s thesis adviser. “I am extremely grateful and appreciative for all the support, guidance, and encouragement he has given me throughout my time at Georgia Tech. He's a phenomenal mentor and advisor, and I wouldn’t have had any success without him.”

Sierra A. Knavel

“I was enthusiastic to hear about receiving the award,” Knavel says, “and eager to join a community that wants to help each other succeed while at Georgia Tech.”

Knavel, whose research interests include low-dimensional topology, has Professor John Etnyre as an adviser. “He is the reason I can say I'm in the math Ph.D. program, and that I know I belong here.”

Tony Lemos

“When I applied to the UCEM fellowship, I had doubts that I was accomplished enough to be chosen for this fellowship,” Lemos says. “When I received the email announcing that I had been selected for this award, it was a great surprise, and I was immediately filled with immense gratitude. I am very thankful to be one of the students to receive this gift that will help me become the first in my family to obtain a doctoral degree.”

Lemos is a research assistant in the biophysics lab of Professor Harold Kim, who is his adviser. “He has been a great mentor who helped me get this far at Georgia Tech. He is a great role model that showed me what it means to be an effective scientist. He also challenged me to grow in areas I was uncomfortable with in the lab. I am thankful for his mentorship and unending support.”

Autumn Peterson

“I was super excited to hear that I was named a UCEM Ph.D. Fellow,” Peterson says. “Mentorship has always been important to me. I would not be in the position I am in now without mentors who have supported me throughout my academic career. I am looking forward to strengthening my mentorship skills and serving as a role model for aspiring scientists coming from underrepresented backgrounds like I do.”

Peterson’s adviser is Associate Professor William Ratcliff, who is also Co-Director of the Interdisciplinary Ph.D. in Quantitative Biosciences. ‘I want to thank him for his immense support throughout my academic journey. I would also like to thank Anthony Burnetti, a senior research scientist in the Ratcliff lab. Both Ratcliff and Burnetti are both extremely supportive, kind, and knowledgeable, and I am grateful to have them as mentors.”

Earlier this year, Peterson and Ratcliff were co-awarded a Howard Hughes Medical Institute (HHMI) Gilliam Fellowship for Advanced Study.

“We are so proud of our UCEM/C-PIES Fellows," says Lea Marzo, C-PIES Program Operations Director. "The students selected for this fellowship are brilliant researchers and we are delighted that Georgia Tech’s Office of the President is making an investment in their success. We cannot wait to see what the future has in store for these fellows."

When you just can’t find anyone to hang out with on a Friday night, it might not be a comfort to know that bacteria may have you beat when it comes to a social life.

“We now know that bacteria can lead complex social lives, communicating and cooperating within multicellular groups,” says Sam Brown, professor in the School of Biological Sciences and a member/past director of Georgia Tech’s Center for Microbial Dynamics and Infection (CMDI).

Getting out and about in the microbial world leaves bacteria facing challenges such as competition from other bacteria, threats from bacteria-eating viruses, drugs that target them, and starvation when they can’t find a host organism. Brown and his fellow CMDI scientists now want to know how bacteria modify their behaviors in response to their social and physical environments.

Two new grants totaling nearly $1.5 million will give them that chance.

One of the grants, a National Science Foundation award, focuses on how bacteria use clustered regularly interspaced short palindromic repeats — better known as CRISPR, a cellular immune system that helps bacteria ward off threats. CRISPR is perhaps best known as a gene editing tool.

The NSF grant also includes Rachel Kuske, professor in the School of Mathematics and a CMDI member, and Edze Westra, Professor of Microbiology at the University of Exeter in the United Kingdom. The NSF is partnering with the UK’s Biotechnology and Biological Sciences Research Council (BBSRC) for this grant.

The other grant from the Army Research Office (ARO) will study quorum sensing, a form of cell-to-cell communication, to determine how bacteria use it to “count” cells so that collective behavior can be turned on.

Both grants can help CMDI understand microbial behavior in ways that could eventually lead to manipulating or controlling bacteria, says Steve Diggle, CMDI director and a professor in the School of Biological Sciences.

“We are delighted by these new grants as they align closely with the core mission of CDMI because they will advance our understanding of microbial interactions, behaviors, and community dynamics,” Diggle says. “The knowledge generated could have transformative impacts on both academic research and practical applications.”

CRISPR protections, but only in a crowd

Brown wants to make it clear that he and his colleagues won’t be doing any CRISPR gene editing themselves. “Our questions are more basic, focused on how the ‘inventors’ of CRISPR, bacteria, use this system to protect themselves from infection by phages (viruses that attack bacteria) and other molecular parasites of cells,” Brown says.

CRISPR’s role is to recognize and cut out specific sequences of foreign DNA within bacteria. Yet what Brown calls the “dirty secret” of microbiology is that lab bacteria rarely use CRISPR to deal with novel viruses.

“Instead, they use the simple trick of deleting the surface receptors that the virus uses to gain entry to the cell,” he explains. Previous work by CMDI Early Career Award Fellow Ellinor Alseth found an answer to this puzzle: bacteria are more likely to use CRISPR as an immune mechanism when they are living in a multi-species community. What Brown hopes to decipher are the molecular and ecological mechanisms that determine how life in a community can activate CRISPR functions.

“We further aim to build mathematical models of community dynamics, capturing both species interactions and evolutionary changes in a focal species undergoing viral attack,” Brown says. “This will have applied significance by helping the design of more robust microbial communities.”

Quorum sensing = a bacterial census

Regarding the ARO grant, Brown says the standard view for quorum sensing is that bacteria use those signals as a way of counting cells. When the extracellular signal is above a certain threshold, the population is “quorate” (that is, reaches a certain number of cells), and collective behaviors can be turned on.

Yet an increasing body of theory, along with experiments in Brown’s lab and others, has challenged this view “by highlighting that quorum sensing behaviors can also be shaped by the physical environment, such as diffusion, flow rate, and containment,” he says.

Also, behaviors are not “turned on” in a threshold manner with increasing density. “In a high density ‘quorate’ environment, not all cells are expressing canonical quorum sensing-controlled behaviors. These challenges leave us with limited understanding of the functional roles of QS.”

“By examining the balance between intracellular mechanisms and multicellular behaviors, we will obtain a more comprehensive understanding of how bacteria collaborate and respond collectively to their environment,” Diggle adds.

Charles Darwin said that evolution was constantly happening, causing animals to adapt for survival. But many of his contemporaries disagreed. If evolution is always causing things to change, they asked, then how is it that two fossils from the same species, found in the same location, can look identical despite being 50 million years apart in age?

Everything changed in the past 40 years, when an explosion of evolutionary studies proved that evolution can and does occur rapidly — even from one generation to the next. Evolutionary biologists were thrilled, but the findings reinforced the same paradox: If evolution can happen so fast, then why do most species on Earth continue to appear the same for many millions of years?

This is known as the paradox of stasis, and James Stroud, assistant professor in the School of Biological Sciences at the Georgia Institute of Technology, set out to investigate it. He conducted a long-term study in a community of lizards, measuring how evolution unfolds in the wild across multiple species. In doing so, he may have found the answer to one of evolution’s greatest challenges.

His research was published as the cover story in the Proceedings of the National Academy of Sciences.

Read the full feature in the GT Research newsroom.

Charles Darwin said that evolution was constantly happening, causing animals to adapt for survival. But many of his contemporaries disagreed. If evolution is always causing things to change, they asked, then how is it that two fossils from the same species, found in the same location, can look identical despite being 50 million years apart in age?

Everything changed in the past 40 years, when an explosion of evolutionary studies proved that evolution can and does occur rapidly — even from one generation to the next. Evolutionary biologists were thrilled, but the findings reinforced the same paradox: If evolution can happen so fast, then why do most species on Earth continue to appear the same for many millions of years?

This is known as the paradox of stasis, and James Stroud, assistant professor in the School of Biological Sciences at the Georgia Institute of Technology, set out to investigate it. He conducted a long-term study in a community of lizards, measuring how evolution unfolds in the wild across multiple species. In doing so, he may have found the answer to one of evolution’s greatest challenges.

His research was published as the cover story in the Proceedings of the National Academy of Sciences.

Read the full feature in the GT Research newsroom.

Mosquitoes are some of the fastest-flying insects. Flapping their wings more than 800 times a second, they achieve their speed because the muscles in their wings can flap faster than their nervous system can tell them to beat.

This asynchronous beating comes from how the flight muscles interact with the physics of the insect’s springy exoskeleton. This decoupling of neural commands and muscle contractions is common in only four distinct insect groups.

For years, scientists assumed these four groups evolved these ultrafast wingbeats separately, but research from the Georgia Institute of Technology and the University of California, San Diego (UC San Diego) shows that they evolved from a single common ancestor. This discovery demonstrates evolution has repeatedly turned on and off this particular mode of flight. The researchers developed physics models and robotics to test how these transitions could occur.

Read the full feature in the GT Research newsroom.

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