Study finds brain's 'wiring insulation' as major factor of age-related brain deterioration

UNIVERSITY OF PORTSMOUTH

Research News

 

IMAGE: THE IMAGE DEPICTS MYELIN (CYAN) AND SPECIALISED BRAIN STEM CELLS OLIGODENDROCYTE PROGENITOR CELLS (OPCS) IN THE GREY AND WHITE MATTER OF THE BRAIN. MYELIN IS AN INSULATION PRODUCED BY CELLS... view more 

CREDIT: DR ANDREA RIVERA

A new study led by the University of Portsmouth has identified that one of the major factors of age-related brain deterioration is the loss of a substance called myelin.

Myelin acts like the protective and insulating plastic casing around the electrical wires of the brain - called axons. Myelin is essential for superfast communication between nerve cells that lie behind the supercomputer power of the human brain.

The loss of myelin results in cognitive decline and is central to several neurodegenerative diseases, such as Multiple Sclerosis and Alzheimer's disease. This new study found that the cells that drive myelin repair become less efficient as we age and identified a key gene that is most affected by ageing, which reduces the cells ability to replace lost myelin.

The study, published this week in the journal Ageing Cell, is part of an international collaboration led by Professor Arthur Butt at the University of Portsmouth with Dr Kasum Azim at the University of Dusseldorf in Germany, together with Italian research groups of Professor Maria Pia Abbracchio in Milan and Dr Andrea Rivera in Padua.

Professor Butt said: "Everyone is familiar with the brain's grey matter, but very few know about the white matter, which comprises of the insulated electrical wires that connect all the different parts of our brains.

"A key feature of the ageing brain is the progressive loss of white matter and myelin, but the reasons behind these processes are largely unknown. The brain cells that produce myelin - called oligodendrocytes - need to be replaced throughout life by stem cells called oligodendrocyte precursors. If this fails, then there is a loss of myelin and white matter, resulting in devastating effects on brain function and cognitive decline. An exciting new finding of our study is that we have uncovered one of the reasons that this process is slowed down in the aging brain."

Dr Rivera, lead author of the study while he was in University of Portsmouth and who is now a Fellow at the University of Padua, explained: "By comparing the genome of a young mouse brain to that of a senile mouse, we identified which processes are affected by ageing. These very sophisticated analysis allowed us to unravel the reasons why the replenishment of oligodendrocytes and the myelin they produce is reduced in the aging brain.

CAPTION

The image depicts myelin (Cyan), OPCs (Magenta) and cell nuclei in blue in the Corpus Callosum of the brain. The Corpus callosum is one of the biggest tracts of white matter and it connects the left and right hemisphere of the brain together. It is also one of the white matter tracts affected by aging.

CREDIT

Dr Andrea Rivera

"We identified GPR17, the gene associated to these specific precursors, as the most affected gene in the ageing brain and that the loss of GPR17 is associated to a reduced ability of these precursors to actively work to replace the lost myelin."

The work is still very much ongoing and has paved the way for new studies on how to induce the 'rejuvenation' of oligodendrocyte precursor cells to efficiently replenish lost white matter.

Dr Azim of the University of Dusseldorf said: "This approach is promising for targeting myelin loss in the aging brain and demyelination diseases, including Multiple Sclerosis, Alzheimer's disease and neuropsychiatric disorders. Indeed, we have only touched the tip of the iceberg and future investigation from our research groups aim to bring our findings into human translational settings."

Dr Rivera performed the key experiments published in this study while at the University of Portsmouth and he has been awarded the prestigious MSCA Seal of Excellence @UniPD Fellowship to translate these findings and investigate this further in the human brain, in collaboration with Professors Raffele De Caro, Andrea Porzionato and Veronica Macchi at the Institute of Human Anatomy of the University of Padua.

The study was funded by grants from the BBSRC and MRC to Professor Butt, together with the UK and Italian MS Societies (to Professors Butt and Abbracchio, respectively), and the Swiss National Funds Fellowship and German Research Council (Dr Azim). Dr Andrea Rivera was supported by an Anatomical Society PhD Studentship (with Professor Butt), and the MSCA Seal of Excellence @UniPD (Dr Rivera).

Dr Emma Gray, Assistant Director of Research at the MS Society, said: "MS can be relentless and painful, and there are sadly still no treatments to stop disability progression. We can see a future where no one has to worry about MS getting worse but, for that to happen, we need to find ways to repair damaged myelin. This research sheds light on why cells that drive myelin repair become less efficient as we age, and we're really proud to have helped fund it. By improving our understanding of ageing brain stem cells, it gives us a new target to help slow the progression of MS, and could have important implications for future treatment."

CAPTION

The image shows a special type of stem cells called oligodendrocyte precursor cells (OPCs) (White). These cells generate another type of brain cell called oligodendrocyte throughout life. Oligodendrocytes produce myelin (Red) which is a substance that promotes efficient transmission of a nerve cell impulse by insulating axons: the part of neurons that transmit the information. The image is of the striatum and a part of corpus callosum (top right).

CREDIT

Dr Andrea Rivera

Study: Prisoners with mental illness much more likely to be placed in solitary confinement

#ABOLISHPRISON 

#SOLITARYISTORTURE

CRIME AND JUSTICE RESEARCH ALLIANCE

Research News

 

Past studies on whether incarcerated people with mental illness are more likely to be placed in solitary confinement have yielded mixed results. A new study examined the issue in one state's prisons, taking into account factors related to incarcerated men and the facilities where they were imprisoned. It found that having a mental illness was associated with a significant increase in the likelihood of being placed in extended solitary confinement.

The study, by researchers at Florida State University (FSU), appears in Justice Quarterly, a publication of the Academy of Criminal Justice Sciences.

"Our findings provide new information on how mental illness shapes experiences for incarcerated men, and more broadly, on how the criminal justice system responds to people with mental illness," explains Sonja Siennick, professor of criminology and criminal justice at FSU, who led the study. "The bottom line is that incarcerated people with mental illness appear to garner differential responses from the prison system."

Solitary confinement--placing incarcerated people in isolation cells for 22 to 24 hours a day--is controversial. While some argue that it helps with safety, others suggest it is unethical and poses psychological risks, especially for prisoners with mental illness. This study focused on extended periods of solitary confinement that last for months.

Researchers studied 155,018 men who entered prisons in a large state on or after July 1, 2007, and were released on or before December 31, 2015. The men were assessed within 60 days of their arrival to determine if they met criteria for psychiatric diagnosis. More than 15,000 of the men were diagnosed with a mental health condition. These men were matched with a control group of the same size--men who had equivalent personal characteristics and were housed in similar facilities but who were not diagnosed with a mental health condition.

The study used propensity score matching, a technique that estimates the effect of an intervention, to assess whether the incarcerated men with mental illness were more likely to be placed in extended solitary confinement than the similar incarcerated men without mental illness. Researchers considered characteristics of both the individual prisoners and the facilities in which they were incarcerated. For the men, these included prior arrests and convictions, recidivism, victimization in prison, age, race/ethnicity, education, alcohol and drug use, family and romantic relationships, and other demographics. For the facilities, these included distance from the incarcerated man's home and information related to the inmate population (e.g., average age, race/ethnicity, percentage in solitary confinement, percentage receiving mental health care) as well as the correctional staff.

The study found that one percent of all of the men were placed in extended solitary confinement after 60 days. It also found that prisoners with mental illness were up to 170 percent more likely to be placed for extended periods of time in solitary, depending on their diagnosis. This increased risk is higher than identified by previous research. The higher risk was present for a variety of mental health disorders (including bipolar disorder, major depression, schizophrenia, psychotic antisocial personality disorder, and other personality disorders, but not disorders related to anxiety, impulse control, and post-traumatic stress), and only partially explained by prison misconduct, the authors note.

Incarcerated men placed in solitary confinement were separated from the general population for months; placed alone in a cell for 23 hours a day; and restricted from using the telephone, having visitors, and receiving other privileges. Reasons for placements included safety concerns, problems with institutional adjustment, and possessing or trafficking contraband such as weapons and drugs.

Among the study's limitations, according to the authors, are that differences in how men and women are housed in the facilities studied prevented a complete examination of women; however, the researchers note that the main results for women were substantively similar to those for men. In addition, because most prisoners in the state serve sentences of less than three years, the study's findings may not generalize to people who are incarcerated for longer periods.

Also, the study examined state prisons and not jails, so the association of mental illness with solitary confinement could differ between these settings. Finally, because a new edition of the Diagnostic and Statistical Manual of Mental Disorders was published midway through the study and included changes to criteria for mental illness, men admitted later in the study could have been diagnosed differently than men admitted earlier.

"Our results suggest that the association between mental illness and solitary confinement is not simply a matter of more violent behavior by this population," says Mayra Picon, a doctoral student in criminology and criminal justice at FSU, who coauthored the study. "Rather, incarcerated men with mental illness may have more difficulty adjusting to prison and its rules, resulting in more punitive responses by prison staff.

"Treatment, officer training, and related initiatives may help offset negative consequences for incarcerated people with mental illness, but first, we must develop a better understanding of the intersection of mental illness and corrections," she added.

###

The research was supported by the National Institute of Justice.

Mothers rebuild: Solutions to overcome

COVID-19 challenges in academia

MICHIGAN TECHNOLOGICAL UNIVERSITY

Research News

 

IMAGE: AMY MARCARELLI, ASSOCIATE PROFESSOR OF BIOLOGY AT MICHIGAN TECH, SEES DIVERSITY, EQUITY, AND INCLUSION THROUGH HER LENS AS AN ECOSYSTEM ECOLOGIST. SHE IS ONE OF 13 CO-AUTHORS ON A PAPER... view more 

CREDIT: SARAH ATKINSON/MICHIGAN TECH

Over the summer and fall, paper after paper revealed that mothers are one of the demographics hardest hit by the pandemic. From layoffs and leaving careers to do caretaking, to submission rate decreases and additional service projects, the data were clear, but the follow up less so. Many of the problems are not new and will remain after the pandemic. But a new paper, published this week in PLOS Biology, outlines methods to help solve them.

"In the spirit of the well-worn adage 'never let a good crisis go to waste,' we propose using these unprecedented times as a springboard for necessary, substantive and lasting change," write the 13 co-authors, led by researchers from Boston University and hailing from seven institutions, including Michigan Technological University, University of Connecticut, and University of Houston - Clear Lake. The team's goal: Solutions for retaining mothers in science during and after COVID-19, especially parents who are Black, Indigenous or people of color.

"The news was reporting these studies as if they were a surprise," said Robinson Fulweiler from Boston University, one of the lead authors alongside Sarah Davies, also of Boston University. Fulweiler adds, "There's already been a lot of data gathered about this issue. But there have been no solutions. Our level of frustration peaked. We decided we need to make a plan to fix things."

The paper offers specific solutions to different groups that can enact change:

• Mentors: Know university parental leave policies, support and model a "healthy work-life teeter-totter" and keep mentees with child care duties engaged and involved in lab, department and multi-institution activities.

• University administrators: Look up 500 Women Scientists, rethink tenure procedures and timelines, listen, provide course releases and avoid making "gender- or race-neutral policies because the effects of the pandemic are not neutral across race or gender."

• Scientific societies: Consider how to keep parts of virtual conferences with lower costs, expand governing board diversity, expand networking opportunities and continue supporting early-career members, especially researchers who are Black, Indigenous, and people of color.

• Publishers: Expand editorial boards and, during the pandemic, incentivize submissions through fee waivers for mothers with child care duties and keep extending deadlines for review and revisions.

• Funding agencies: Streamline paperwork, ask for COVID disruption statements and look into supplemental and short-term bridge awards.

Mothers in the Pandemic

Amy Marcarelli, associate professor of biological sciences at Michigan Tech, helped lead the paper's section addressing professional societies. When the pandemic hit -- and Marcarelli had less than five days to shift all her classes and research to remote formats -- she was wrapping up a two-year strategic planning process with the Society for Freshwater Science that included a deep dive into effective and fair practices for diversity, equity and inclusion. She sees the work through her lens as an ecosystem ecologist.

"Some of my most recent work has been around cascading and indirect effects and how effects viewed on short time scales may have very different outcomes at long time scales," Marcarelli said. "What I've learned from that research is that you can't abstract a single characteristic of an organism and expect that to explain its ecological role. And [in academia] we try so often to treat ourselves as researchers -- and not as mothers and partners and daughters and leaders -- and that's to the detriment of all of us. It's to the detriment of us as individuals but it's also to the detriment of our academic system because if we don't treat people as whole people then we fail them."

Marcarelli emphasizes that she feels like she has been lucky during the pandemic; she secured tenure several years ago, her kid is older, Michigan K-12 schools reopened in September, and her mom, who was furloughed, helped with spring schooling and summer child care. While the extra service projects and retooling research, instruction and life were not easy, Marcarelli recognizes that not everyone's situation has been like hers.

The most pressing change Marcarelli sees is to rethink tenure extensions: "We have to figure out how to make motherhood and tenure compatible, not just extend tenure -- it's not a solution." She adds that the greatest challenge will be money. "These are inequities, but they are not inequities that everybody sees. And during a time of what is going to be an extended budget crisis in a lot of higher ed, that's going to be the hardest part. But it's the part that has to be solved because good intentions only get us so far."

Marcarelli says the conversation that sparked the PLOS Biology article started on Twitter, a lively back-and-forth on how to shift the dialogue to a solutions mindset.

"At the same time, several of us were working on big service activities around how to improve conditions for all different axes of diversity in our departments and universities, in our societies," she said. "We had invested a lot of thinking and real work that was going into small reports and small-scale documents that weren't going to be read widely."

The team's service work, lived experiences and hope informed the PLOS Biology paper as much as their research and collaboration.

"Part of the motivation for writing this article is that in some ways the pandemic provides a window into why this is important, why we need to do the hard work of dismantling these systems," Marcarelli said. "Quite frankly, it's an opportunity."

###

Collaborators

"While the data are clear that mothers are being disproportionally impacted by COVID-19, many groups could benefit from these strategies. Rather than rebuilding what we once knew, let us be the architects of a new world."

Robinson Fulweiler and Sarah Davies, Boston University

Jennifer Biddle, University of Delaware

Amy J. Burgin, University of Kansas

Emily Cooperdock and Carley Kenkel, University of Southern California, Los Angeles

Torrence Hanley, Northeastern University

Amy Marcarelli, Michigan Technological University

Catherine Matassa, University of Connecticut

Talea Mayo, Emory University

Lory Santiago-Vazquez, University of Houston - Clear Lake

Nikki Traylor-Knowles, University of Miami

Maren Ziegler, Justus Liebig University Giessen

#IWD

Re-envisioning the nursing PhD degree

UNIVERSITY OF PENNSYLVANIA SCHOOL OF NURSING

Research News

 

PHILADELPHIA (March 9, 2021) - The PhD degree prepares nurse scientists to advance knowledge through research that improves health, translates into policy, and enhances education. However, as the role of the nurse has changed, and health care has grown more complex, there is a need to re-envision how PhD programs can attract, retain, and create the nurse-scientists of the future and improve patient care.

To begin the dialog about the future of PhD education in research-intensive schools, the University of Pennsylvania School of Nursing (Penn Nursing) invited 41 educational, governmental, professional, and philanthropic institutions to a summit in 2019. During the summit, participants collaborated on re-envisioning how nursing PhD programs can successfully advance nursing science and situate research-focused nursing PhD graduates for success in academia and beyond. An upcoming issue of the Journal of Professional Nursing features manuscripts from that forum, which offer a broader, overall strategy for informing stakeholder groups that shape nursing PhD programs in research-intensive institutions.

"This synthesis of discussions, considerations, and challenges affecting research-focused doctoral programs of nursing serve as a basis and catalyst for further discussion and action to ensure PhD research-focused programs are preparing successful nurse scientists of the future," says Antonia M. Villarruel, PhD, RN, FAAN, Professor and Margaret Bond Simon Dean of Nursing.

"Re-envisioning of research doctorate programs is urgently needed to ensure the advancement of science and the development of new knowledge to situate our graduates for success - in academia and beyond," says Julie A. Fairman, PhD, RN, FAAN, Endowed Chair, Nightingale Professor in Honor of Nursing Veterans. Villarruel and Fairman were guest editors of the issue.

Advancing Nursing Science Through Re-envisioned PhD Programs

PhD programs, in general, remain fairly traditional in approach and scope, instigating few changes in programmatic offerings and moving existing curriculum online. The Penn Nursing summit in 2019 was held to address these issues.

The article "Invitational Summit: Re-envisioning Research-Focused PhD Programs of the Future" shares the questions used to survey the summit attendees before the program and the responses. The article outlines the challenges facing research-intensive nursing PhD programs, emerging innovations within programs, and suggested changes to re-envision the future education of nurse scientists.

Fairman and Villarruel co-authored the article with Kathleen McCauley, PhD, RN, FAAN, FAHA, Professor Emerita of Cardiovascular Nursing at Penn Nursing; and Nicholas A. Giordano, Assistant Professor, Emory University Nell Hodgson Woodruff School of Nursing.

Approaching Doctoral Nursing Education in Novel Ways

The rapid growth of science and the need to prepare the next generation of nurse scientists call for innovative approaches in educating and supporting them throughout their careers. Aside from curricular changes, a new PhD education model for nurses should include new approaches to mentoring, funding, and networking supports. Equally important are rigorous process and outcome measures for innovations to inform changes to doctoral programs.

The article "Innovations in PhD Education to Prepare Nurse Scientists for the Future" outlines those recommendations and includes the need to structure faculty development earlier in professorial careers, develop team models of advisement, and longitudinal follow-up of alumni graduates from PhD programs to examine the effectiveness of innovations.

Villarruel co-authored the article with Marion E. Broome, Duke University School of Nursing; and Hilaire J. Thompson, University of Washington School of Nursing.

Advancing Nursing Science Through PhD Programs

Nurses are well-positioned to be groundbreaking researchers, scientists, leaders, and innovators to improve the health and well-being of individuals, families, and communities. Thoughtful consideration is required about the preparation of PhD nurse scientists to ensure they are equipped with the knowledge and skill sets to meet the needs of society and to ensure the relevance and competitive status of nursing science.

The article "PhD Programs and the Advancement of Nursing Science" outlines three aspects of PhD education and nursing science. These include examining important elements to support nurse scientist development; identifying key gaps in science that the discipline needs to address in educating the next generation of nurse scientists; and preparing nurse scientists for the competitive funding environment.

Authors of the article include Therese S. Richmond, PhD, RN, FAAN, Andrea B. Laporte Professor of Nursing and Associate Dean for Research & Innovation at Penn Nursing; Paule V. Joseph, of the National Institute of Nursing Research; and Linda McCauley of the Emory University Nell Hodgson Woodruff School of Nursing.

Leveraging Insight from Funders and Sponsors

Re-envisioning PhD education at research-intensive institutions to produce the nurse scientists of the future is imperative for the discovery of solutions for current and complex health care challenges facing the country. Philanthropic funders and sponsors of PhD nursing education have important insights into how investments in PhD education have direct and positive impacts on health care and bring important perspectives to emerging roles for PhD-prepared nurses.

The article, "Emerging Roles for Research Intensive Ph.D.-Prepared Nurses as Leaders and Innovators: Views from Funders/Sponsors" reports on the ideas these funders shared, including the importance of increasing the focus on formal leadership preparation and training in innovation.

Co-authors of the article include Nancy A. Hodgson, PhD, RN, FAAN, Professor & Chair of the Department of Biobehavioral Health Sciences; MaryJoan Ladden, formerly of Robert Wood Johnson Foundation; Elizabeth Madigan, Sigma Theta Tau International Honor Society of Nursing; Ahrin Mishan, Rita and Alex Hillman Foundation; and Wanda Montalvo, Jonas Nursing & Veterans Healthcare.

Preparing Nurses for Nontraditional Career Paths

Advancing the health of patients and communities depends on preparing the next generation of nurse scientists to pursue career trajectories outside of traditional academic institutions. Redesigning nursing PhD curricula must include preparation for careers in many sectors of health care, professional organizations, government, or industry.

During the summit, executives from health systems and organizations shared their career trajectories, experiences, and perspectives for revamping PhD curriculum and offered educational experiences to broaden the scope of academic rigor to inspire and prepare future nurse scientists for nontraditional research positions in practice. Their thoughts regarding why research-intensive PhD programs must address the PhD study milestones to enable their graduates to be competitive in seeking positions in emerging roles outside of academic institutions and recommendations for achieving these milestones are included in the article "Emerging Roles for Research Intensive PhD Prepared Nurses: Beyond Faculty Positions."

Rosemary C. Polomano, PhD, RN, FAAN, Associate Dean for Practice Professor of Pain Practice, is the lead author of the article. Co-authors include Nicholas A. Giordano, Emory University Nell Hodgson Woodruff School of Nursing; Suzanne Miyamoto, American Academy of Nursing; Deborah Trautman, American Association of Colleges of Nursing; Sheila Kempf, Penn Medicine Princeton Health; and Paula Milone Nuzzo, Massachusetts General Hospital.

Pedagogical Innovations in PhD Nursing Education

Over the past decade there have been numerous innovations in PhD programs that have redesigned the curricula and delivery of research-focused doctoral nursing education. The article, "Opportunities and Challenges Presented by Recent Pedagogical Innovations in Doctoral Nursing Education," explores core issues resulting from key program changes such as expanding both 3-year and PhD programs and BSN to PhD programs. This paper makes the case for a national effort to evaluate the effects of these program modifications on the development of nurse scientists and, ultimately, the nursing discipline. Understanding the impact of pedagogical innovations will inform ongoing improvements essential to educate the next generation of nurse scientists to conduct high quality research in an increasingly multidisciplinary environment.

Authors of the article include Mary D. Naylor, PhD, RN, FAAN, Marian S. Ware Professor in Gerontology & Director of the NewCourtland Center for Transitions and Health; Peggy Compton, PhD, RN, FAAN, van Ameringen Chair in Psychiatric and Mental Health Nursing; Nicholas A. Giordano, Emory University Nell Hodgson Woodruff School of Nursing; Paule V. Joseph, National Institute of Nursing Research; Carol Ann Romano, Uniformed Services University of the Health Sciences; and Mariann R. Piano, Vanderbilt University School of Nursing.

PhD Programs of the Future

Over the last 20 years, the number of research-focused doctoral programs in nursing has nearly doubled--from 78 programs in 1999 to 145 programs in 2019. Yet, despite this significant increase in programs, the number of students pursuing the PhD (or equivalent programs) in nursing has declined over the past five years.

From recruiting strategies and subject areas to evaluation methods and funding, discussions at both the Penn Nursing summit and the AACN Doctoral Education Conference authors identified opportunities for improving research-focused doctoral programs for nurses. The article "From Vision to Action: Next Steps In Designing PhD Programs of the Future" synthesizes those discussions and outlines next steps in refining doctoral education in general and in research-focused programs in particular.

Villarruel is lead author with co-authors Fairman and Deborah Trautman, American Association of Colleges of Nursing.

###

About the University of Pennsylvania School of Nursing

The University of Pennsylvania School of Nursing is one of the world's leading schools of nursing. For the sixth year in a row, it is ranked the #1 nursing school in the world by QS University and is consistently ranked highly in the U.S. News & World Report annual list of best graduate schools. Penn Nursing is ranked as one of the top schools of nursing in funding from the National Institutes of Health. Penn Nursing prepares nurse scientists and nurse leaders to meet the health needs of a global society through innovation in research, education, and practice. Follow Penn Nursing on: Facebook, Twitter, LinkedIn, & Instagram.

Study uncovers spawning preferences of mahi-mahi

The UM Rosenstiel-led study can help better manage the valuable marine fish and understand climate change impacts

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE & ATMOSPHERIC SCIENCE

Research News

 

IMAGE: CAPTIVE SPAWNING MAHI-MAHI, OR DOLPHINFISH, TAGGED BY THE RESEARCH TEAM LOCATED AT THE UM EXPERIMENTAL HATCHERY WERE USED TO BUILD PREDICTIVE SPAWNING MODELS. view more 

CREDIT: DAN DINICOLA

MIAMI--In the Florida Straits at night, and under a new moon is the preference for spawning mahi-mahi, according to a new study by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science.

These new details on the daily life of the highly sought-after migratory fish can help better manage their populations and provide scientists with new information to understand the impacts to the animal from changing environmental conditions.

To uncover these important details about the behaviors of mahi-mahi, or dolphinfish, the research team tagged captive spawning fish located at the UM Experimental Hatchery to build predictive spawning models and then used the models with data collected from mahi-mahi tagged in the wild. The study is the first to use acceleration data from remotely transmitting pop-up satellite tags to predict the spawning habitat of a wild marine fish. The UM Experimental Hatchery is the only place in the country where spawning mahi-mahi are kept in captivity.

To build the predictive models, the research team tagged five spawning mahi-mahi (Coryphaena hippurus) at the UM Hatchery and waited overnight to record the timing of when they spawned. In total, 40 individual spawning events were tracked in captivity. Then, they paired the acceleration data collected from the tags with the exact time of spawning to estimate when the animals would spawn in the wild.

To test the models' capability to estimate where and when the fish spawned in the wild, the researchers tagged 17 wild mahi-mahi off the coast of Miami and two in the Gulf of Mexico.

From an analysis of the satellite tag data, the researchers found that wild mahi-mahi spawn at night, primarily during a new moon at depths greater than they would normally be. The Florida Straits appeared to be an important spawning habitat for mahi-mahi, although the models suggest that some limited spawning takes place further north.

They found that mahi-mahi typically go deeper in the water column at night and are more surface oriented during the day. However, the phase of the moon had an effect on their nighttime depth distribution with a full moon bringing mahi-mahi closer to the surface at night.

They also found that mahi-mahi use behavioral thermoregulation to stay between a relatively narrow temperature window of about 27-28 degrees Celsius (80 - 82 degrees Fahrenheit). When surface waters are warmer, they move deeper and swim northward with the Gulf Stream to regulate their temperature, while fish tagged in cooler months stayed primarily in surface waters and migrated east and west between Florida and the Bahamas, rather than swimming north. They were also found to be the most active at cooler temperatures and in warm waters during a full moon at night.

"Mahi-mahi are highly sought after by recreational and commercial fisheries and are economically important," said Lela Schlenker, an alumna of the UM Rosenstiel school and lead author of the study. "It is critical to understand their migrations and the frequency, timing, and location of where they reproduce as well as how changing environmental conditions--like warmer oceans--might affect them to manage their populations sustainably now and in the future."

The team also found from the satellite tag data that the wild mahi-mahi travel long distances--up to 107 kilometers (105 miles) per day and dive to depths of 250 meters (820 feet).

"Together these findings suggest that as climate change continues to warm ocean waters, mahi-mahi will likely continue to shift northward and deeper throughout their migrations," said Martin Grosell," professor and chair of the Department of Marine Biology and Ecology at the UM Rosenstiel School. "This is important for recreational and commercial landings of mahi-mahi and the ecology of pelagic ecosystems. A fruitful collaboration between scientists from three departments at the Rosenstiel School, as well as colleagues from University of Massachusetts, Dartmouth and access to healthy spawning mahi-mahi in captivity revealed new information about these valuable fish," said Grosell.

###

The study, titled "Remote predictions of mahi-mahi (Coryphaena hippurus) spawning in the open ocean using summarized accelerometry data," was published March 9, 2021 in the journal Frontiers in Marine Science. The coauthors include: John Stieglitz, Ronald Hoenig, Rachael Heuer, Daniel Benetti, Claire Paris and Martin Grosell from the UM Rosenstiel School; UM Rosenstiel alumnas Lela S. Schlenker and Christina Pasparakis and former UM postdoctoral researchers Robin Faillettaz and Georgina Cox. Chi Hin Lam, Large Pelagics Research Center, School for the Environment, University of Massachusetts, Boston. The study was funded by GoMRI (grant # SA-1520) to the RECOVER consortium.

UH OH

Diphtheria risks becoming major global threat again as it evolves antimicrobial resistance

UNIVERSITY OF CAMBRIDGE

Research News

 

Diphtheria - a relatively easily-preventable infection - is evolving to become resistant to a number of classes of antibiotics and in future could lead to vaccine escape, warn an international team of researchers from the UK and India.

The researchers, led by scientists at the University of Cambridge, say that the impact of COVID-19 on diphtheria vaccination schedules, coupled with a rise in the number of infections, risk the disease once more becoming a major global threat.

Diphtheria is a highly contagious infection that can affect the nose and throat, and sometimes the skin. If left untreated it can prove fatal. In the UK and other high-income countries, babies are vaccinated against infection. However, in low- and middle-income countries, the disease can still cause sporadic infections or outbreaks in unvaccinated and partially-vaccinated communities.

The number of diphtheria cases reported globally has being increasing gradually. In 2018, there were 16,651 reported cases, more than double the yearly average for 1996-2017 (8,105 cases).

Diphtheria is primarily caused by the bacterium Corynebacterium diphtheriae and is mainly spread by coughs and sneezes, or through close contact with someone who is infected. In most cases, the bacteria cause acute infections, driven by the diphtheria toxin - the key target of the vaccine. However, non-toxigenic C. diphtheria can also cause disease, often in the form of systemic infections.

In a study published today in Nature Communications, an international team of researchers from the UK and India used genomics to map infections, including a subset from India, where over half of the globally reported cases occurred in 2018.

By analysing the genomes of 61 bacteria isolated from patients and combining these with 441 publicly available genomes, the researchers were able to build a phylogenetic tree - a genetic 'family tree' - to see how the infections are related and understand how they spread. They also used this information to assess the presence of antimicrobial resistance (AMR) genes and assess toxin variation.

The researchers found clusters to genetically-similar bacteria isolated from multiple continents, most commonly Asia and Europe. This indicates that C. diphtheriae has been established in the human population for at least over a century, spreading across the globe as populations migrated.

The main disease-causing component of C. diphtheriae is the diphtheria toxin, which is encoded by the tox gene. It is this component that is targeted by vaccines. In total, the researchers found 18 different variants of the tox gene, of which several had the potential to change the structure of the toxin.

Professor Gordon Dougan from the Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID) said: ""The diphtheria vaccine is designed to neutralise the toxin, so any genetic variants that change the toxin's structure could have an impact on how effective the vaccine is. While our data doesn't suggest the currently used vaccine will be ineffective, the fact that we are seeing an ever-increasing diversity of tox variants suggests that the vaccine, and treatments that target the toxin, need to be appraised on a regular basis."

Diphtheria infections can usually be treated with a number of classes of antibiotic. While C. diphtheriae resistant to antibiotics have been reported, the extent of such resistance remains largely unknown.

When the team looked for genes that might confer some degree of resistance to antimicrobials, they found that the average number of AMR genes per genome was increasing each decade. Genomes of bacteria isolated from infections from the most recent decade (2010-19) showed the highest average number of AMR genes per genome, almost four times as many on average than in the next highest decade, the 1990s.

Robert Will, a PhD student at CITIID and the study's first author, said: "The C. diphtheriae genome is complex and incredibly diverse. It's acquiring resistance to antibiotics that are not even clinically used in the treatment of diphtheria. There must be other factors at play, such as asymptomatic infection and exposure to a plethora of antibiotics meant for treating other diseases."

Erythromycin and penicillin are the traditionally recommended antibiotics of choice for treating confirmed cases of early-stage diphtheria, though there are several different classes of antibiotics available to treat the infection. The team identified variants resistant to six of these classes in isolates from the 2010s, higher than in any other decades.

Dr Pankaj Bhatnagar from the World Health Organization country office for India said: "AMR has rarely been considered as a major problem in the treatment of diphtheria, but in some parts of the world, the bacterial genomes are acquiring resistance to numerous classes of antibiotics. There are likely to be a number of reasons to this, including exposure of the bacteria to antibiotics in their environment or in asymptomatic patients being treated against other infections."

The researchers say that COVID-19 has had a negative impact on childhood vaccination schedules worldwide and comes at a time when reported case numbers are rising, with 2018 showing the highest incidence in 22 years.

Dr Ankur Mutreja from CITIID, who led the study, said: "It's more important than ever that we understand how diphtheria is evolving and spreading. Genome sequencing gives us a powerful tool for observing this in real time, allowing public health agencies to take action before it's too late.

"We mustn't take our eye off the ball with diphtheria, otherwise we risk it becoming a major global threat again, potentially in a modified, better adapted, form."

###

The research was funded primarily by the Medical Research Council, with additional support from the NIHR Cambridge Biomedical Research Centre.

Reference

Will, RC et al. Spatiotemporal persistence of multiple, diverse clades and toxins of Corynebacterium diphtheria. Nat Comms; 8 Mar 2021; DOI: 10.1038/s41467-021-21870-5

Oceans were stressed preceding abrupt, prehistoric global warming

Shelled organisms helped buffer ocean acidification by consuming less alkalinity from seawater

NORTHWESTERN UNIVERSITY

Research News

 

IMAGE: SCANNING ELECTRON MICROSCOPY IMAGES OF FORAMINIFERA FROM DIFFERENT ANGLES. view more 

CREDIT: NORTHWESTERN UNIVERSITY

Microscopic fossilized shells are helping geologists reconstruct Earth's climate during the Paleocene-Eocene Thermal Maximum (PETM), a period of abrupt global warming and ocean acidification that occurred 56 million years ago. Clues from these ancient shells can help scientists better predict future warming and ocean acidification driven by human-caused carbon dioxide emissions.

Led by Northwestern University, the researchers analyzed shells from foraminifera, an ocean-dwelling unicellular organism with an external shell made of calcium carbonate. After analyzing the calcium isotope composition of the fossils, the researchers concluded that massive volcanic activity injected large amounts of carbon dioxide into the Earth system, causing global warming and ocean acidification.

They also found that global warming and ocean acidification did not just passively affect foraminifera. The organisms also actively responded by reducing calcification rates when building their shells. As calcification slowed, the foraminifera consumed less alkalinity from seawater, which helped buffer increasing ocean acidity.

"The formation and dissolution of calcium carbonate help regulate the acidity and alkalinity of seawater," said Northwestern's Andrew Jacobson, a senior author of the study. "Our calcium isotope data indicate that reduced foraminiferal calcification worked to dampen ocean acidification before and across the PETM."

"This is a pretty new concept in the field," added Gabriella Kitch, the study's first author. "Previously, people thought that only the dissolution of carbonates at the sea floor could increase alkalinity of the ocean and buffer the effects of ocean acidification. But we are adding to existing studies that show decreased carbonate production has the same buffering effect."

The research was published online last week (March 4) in the journal Geology. This is the first study to examine the calcium isotope composition of foraminifera to reconstruct conditions before and across the PETM and the third recent Northwestern study to find that ocean acidification -- due to volcanic carbon dioxide emissions -- preceded major prehistoric environmental catastrophes, such as mass extinctions, oceanic anoxic events and periods of intense global warming.

Jacobson is a professor of Earth and planetary sciences at Northwestern's Weinberg College of Arts and Sciences. Kitch is a Ph.D. candidate and National Science Foundation Graduate Research Fellow in Jacobson's laboratory. Northwestern Earth science professors Bradley Sageman and Matthew Hurtgen, as well as collaborators from the University of California-Santa Cruz (UCSC) and the University of Kansas, coauthored the paper with Jacobson and Kitch.

CAPTION

Scanning electron microscopy images of foraminifera from different angles

CREDIT

Northwestern University

Sorting microscopic shells

To study oceanic conditions during the PETM, the researchers examined the calcium isotope composition of foraminiferal fossils collected from two sites -- one in the southeast Atlantic Ocean and one in the Pacific Ocean -- by the Ocean Drilling Program.

Because each fossilized shell is about the size of a single grain of sand, UCSC researchers physically collected the tiny specimens by first identifying them under a microscope. After sorting the shells from bulk sediments, the Northwestern team dissolved the samples and analyzed their calcium isotope composition using a thermal ionization mass spectrometer.

"The work is very challenging," Jacobson said. "To manipulate these tiny materials, you have to pick them up, one by one, with a wet paintbrush tip under a microscope."

Stress prior to PETM

As the shells formed more than 56 million years ago, they responded to oceanic conditions. By examining these shells, the Northwestern team found that calcium isotope ratios increased prior to the onset of the PETM.

"We are looking at one group of organisms that built their shells in one part of the ocean, recording the seawater chemistry surrounding them," Kitch said. "We think the calcium isotope data reveal potential stress prior to the well-known boundary."

Other archives indicate that the atmosphere-ocean system experienced a massive carbon dioxide release immediately before the PETM. When atmospheric carbon dioxide dissolves in seawater, it forms a weak acid that can inhibit calcium carbonate formation. Although it is still undetermined, Earth scientists believe the carbon release most likely came from volcanic activity or cascading effects, such as a release of methane hydrates from the seafloor as a result of ocean warming.

"My suspicion is that it's both of these factors or some sort of combination," Sageman said. "Most big events in Earth's history represent a confluence of many actors coming together at the same time."

Consistent pattern emerges

This is the third study led by Jacobson to find that ocean acidification precedes major environmental catastrophes that correlate with large igneous province eruptions. Last month, Jacobson's team published results finding that volcanic activity triggered a biocalcification crisis prior to an ocean anoxic event that occurred 120 million years ago. Just over a year ago, Jacobson's team published another study finding ocean acidification preceded the asteroid impact leading to the Cretaceous-Paleogene mass extinction event 66 million years ago, which included the demise of dinosaurs.

In all three studies, Jacobson's team used sophisticated tools in his laboratory to analyze the calcium isotope composition of calcium carbonate fossils and sediment. Jacobson said a clear pattern is emerging. Influxes of carbon dioxide led to global warming and ocean acidification and, ultimately, to massive environmental changes.

"In all of our studies, we consistently see an increase in calcium isotope ratios before the onset of major events or extinction horizons," Jacobson said. "This seems to point to similar drivers and common responses."

"Perhaps the calcium isotope system has a sensitivity to the earliest phases of these events," Sageman added.

Predictor for future ocean stress

Many researchers study the PETM because it provides the best analog for current-day, human-caused global warming. The carbon influx during the PETM is similar to the amount of carbon released during the past two centuries. The timescales, however, differ significantly. Temperatures during the PETM increased by 5 to 8 degrees Celsius over 170,000 years. With human-caused climate change, the same level of warming is projected to occur in less than 200 years, if carbon dioxide emissions remain unabated.

Frighteningly, terrestrial and ocean stress, including a major decrease in foraminiferal calcification, accompanied the PETM.

"The PETM is a model for what happens during major large carbon cycle perturbations," Jacobson said. "A lot of predictions for Earth's future climate rely on understanding what happened during the PETM."

###

The study, "Calcium isotope composition of Morozovella over the Late Paleocene-early Eocene," was supported by a David and Lucile Packard Fellowship (award number 2007-31757) and the National Science Foundation (award numbers NSF-EAR 0723151 and DGE-1842165).

 ARCHNAPHOBIA TRIGGER WARNING OPPS TOO LATE

Two species and a single name: 'Double identity' revealed in a venomous banana spider

PENSOFT PUBLISHERS

Research News

 

IMAGE: PHONEUTRIA BOLIVIENSIS IN THE PERUVIAN AMAZON. view more 

CREDIT: N. HAZZI

Spiders from the genus Phoneutria - also known as banana spiders - are considered aggressive and among the most venomous spiders in the world, with venom that has a neurotoxic action. These large nocturnal spiders usually inhabit environments disturbed by humans and are often found in banana plantations in the Neotropical region.

One of these spiders, P. boliviensis, is a medically important species widely distributed in Central and South America, whose behaviour, habitat, venom composition, toxicity and bites on humans have already been paid considerable attention in previous research work. Nevertheless, after examining a large pool of museum specimens, biologists from The George Washington University (N. Hazzi and G. Hormiga) began to wonder if samples named P. boliviensis were actually belonging to one and the same species.

Everything started when N. Hazzi was examining specimens of banana spiders identified in the past by experts as P. boliviensis. The research team quickly realized that the morphological features currently used to identify this species were not sufficient. Then, they discovered two well-defined morphological groups of P. boliviensis that were separated by the Andean mountain range, a geographic barrier that separates many other species.

To prove that these two "forms" were different species, the authors conducted fieldwork in the Amazon, Andes, and Central America, collecting specimens of these venomous spiders to explore if the genomic signal also suggests two species. They discovered that genetic differences separating these two forms were similar compared to the genetic differences separating other recognized species of banana spiders. Using morphological, genomic and geographic distribution data, the authors concluded that P. boliviensis represents not a single species, but two different ones. They uncovered that the true P. boliviensis was only found in the Amazonian region, and the second species, P. depilata (an old name revalidated by the research team), was found in the Andes, Chocó and Caribbean regions. Their findings are published in the open-access, peer-reviewed journal ZooKeys.

To obtain more distribution records for these species, the research team used the citizen science platform iNaturalist. Since the two species are among the few spiders that can be identified using only images, the platform turned out to be a very helpful tool. Data submitted by the iNaturalist community helped identify where the two species of Phoneutria are found. Curiously enough, for these two species, iNaturalist presented higher and more widely distributed records than the scientists' own database.

"To our knowledge, this is the first study that has used iNaturalist to gather occurrence records on venomous species to estimate distribution models," the researchers say.

This is how the two spiders can be distinguished using only photographs: P. boliviensis has two lateral white-yellow bands in the anterior area of the carapace, while P. depilata has four series of yellow dots in the ventral side of the abdomen. In addition, for P. depilata's identification, information is needed on where the image was taken, because this is the only species of Phoneutria found in the Andes, Chocó, and Central America. However, the most reliable approach to identify these species requires examination under a stereomicroscope.

Interestingly, P. depilata has been mislabeled as P. boliviensis throughout many studies, including works on venom composition and toxicity, ecology, geographic distribution, and human epidemiology of bites. There have been human bite records of this species reported in Costa Rica and in banana plantations in Colombia, most of them with mild to moderate envenomation symptoms. Except for brief anecdotal mentions by field explorers in the Amazon, little is known about P. depilata.

The study provides detailed diagnoses with images to distinguish both species and distribution maps.

"This valuable information will help identify risk areas of accidental bites and assist health professionals in determining the identity of the species involved, especially for P. depilata. This is a significant discovery that will affect studies about toxicology, opening new opportunities to compare the venom composition and the effect of these two species," the authors conclude.

Research article:

Hazzi NA, Hormiga G (2021) Morphological and molecular evidence support the taxonomic separation of the medically important Neotropical spiders Phoneutria depilata (Strand, 1909) and P. boliviensis (F.O. Pickard-Cambridge, 1897) (Araneae, Ctenidae). ZooKeys 1022: 13-50. https://doi.org/10.3897/zookeys.1022.60571

CAPTION

Genetic evolutionary tree of the banana spiders genus Phoneutria

Ageing DR Congo artists keep music of the miners alive

Dancer Jean-Marie Manga, left, and guitarist-singer Marcel Tshibanda, perform in front of the Gecamines plant in Lubumbashi 

Samir TOUNSI AFP

Issued on: 09/03/2021 - 

Lubumbashi (DR Congo) (AFP)

The cone-shaped slag heap in the southeastern Congolese city of Lubumbashi is a mighty symbol of the time when copper was king.

In that heady era, a vibrant and distinctive culture of music and dancing sprouted among miners who worked for DR Congo's state giant, Gecamines.

Today, just a small number of performers are still around to play the songs and do the dances, and recount what it was like in the glory days.

One of them is Marcel Tshibanda, once a guitarist with a Jecoke group -- a troupe of employees who were paid by Gecamines' social club to sing and dance for mining communities in their spare time.

Their music had a distinctive, calypso-y beat and the dancers dressed in smart long-tailed suits, wowing the crowds with snappy trademark moves.

The sound, said Tshibanda, was inspired by musicians in neighbouring Zambia, previously a British colony.

"The English had this rhythm, it was like this," said Tshibanda, tapping out a snazzy two-beat signature on his hand-made guitar.

The Jecokes' name derives from the French words for Comic Youth of Kenya -- Kenya being a rundown district of Lubumbashi.

For decades, right until the 1980s, Gecamines was "a state within a state," recalled Pierre Katamba, a former member of the troupe.

"We used to call it 'mum and dad.' You would get free medical treatment and the children got free education."

- 'Things are tough' -

The halcyon era started to crumble in the 1990s, when globalisation began to hit the mining industry, followed by political upheaval in distant Kinshasa and then two regional wars.

In 2003, the World Bank funded a redundancy programme to cut 10,655 workers from Gecamines' payroll of 36,000, although a chunk of the money has gone missing in a country notorious for corruption.

Gecamines retains its central role in the Democratic Republic of Congo's economic strategy.

But its focus these days is cobalt, the key mineral in batteries for electronic devices.

With Gecamines' decline, times and taste changed. A few years from now, who will remember the Jecoke?

"Everyone abandoned Jecoke music to get into rumba," said Tshibanda.

"To put it in a nutshell, things are tough," said fellow 74-year-old Laurent Ilunga Kazadi, still resplendent in his suit.