The cellular energy sensor AMP-activated protein kinase (AMPK) is a metabolic regulator that mediates adaptation to nutritional variations to maintain a proper energy balance in cells. We show here that suckling-weaning and fasting-refeeding transitions in rodents are associated with changes in AMPK activation and the cellular energy state in the liver. These nutritional transitions were characterized by a metabolic switch from lipid to glucose utilization, orchestrated by modifications in glucose levels and the glucagon/insulin ratio in the bloodstream. We therefore investigated the respective roles of glucose and pancreatic hormones on AMPK activation in mouse primary hepatocytes. We found that glucose starvation transiently activates AMPK, whereas changes in glucagon and insulin levels had no impact on AMPK. Challenge of hepatocytes with metformin-induced metabolic stress strengthened both AMPK activation and cellular energy depletion under limited-glucose conditions, whereas neither glucagon nor insulin altered AMPK activation. Although both insulin and glucagon induced AMPKα phosphorylation at its Ser485/491 residue, they did not affect its activity. Finally, the decrease in cellular ATP levels in response to an energy stress was additionally exacerbated under fasting conditions and by AMPK deficiency in hepatocytes, revealing metabolic inflexibility and emphasizing the importance of AMPK for maintaining hepatic energy charge. Our results suggest that nutritional changes (i.e. glucose availability), rather than the related hormonal changes (i.e. the glucagon/insulin ratio), sensitize AMPK activation to the energetic stress induced by the dietary transition during fasting. This effect is critical for preserving the cellular energy state in the liver.

Carlos Gustavo T. Moreira, Maria José Pacifico and Sergio Romaña Ibarra
Bull. Amer. Math. Soc. 57 (2018), 269-292.
Abstract, references and article information

Araceli Bonifant and John Milnor
Bull. Amer. Math. Soc. 57 (2020), 171-267.
Abstract, references and article information

Seventy-year-old Theresa Chan suffers from joint degeneration, which is why she needs a walking stick.

“My joints are severely abraded. They are painful when I walk or stand. My doctor suggested I replace some joints with implants, but I don't want surgery,” she said.

Smart seniors

Interested in how gerontechnology can help improve the quality of life for older adults, Ms Chan joined the Gerontechnology Practitioner Training Course under Lingnan University’s Gerontechnology & Smart Ageing Project.

The course targets elderly people and caregivers. It introduces them to devices that help seniors get around with ease and live more independent lives.

Ms Chan was impressed by a smart walking stick that is equipped with senior-worthy features like a flashlight with an adjustable safety light, a siren for emergency use and a radio.

“I am grateful for the course because I can learn more about gerontechnology in my free time. After class, I can share my knowledge with others who have no idea about this new technology. It is modern and I want to keep up with the times and progress,” she said.

Youth opportunities

Gerontechnology has also opened up career opportunities for young people.

Cecilia Auyeung recently graduated from Lingnan University with a major in marketing. Last year she set up a social enterprise called Gatherly. It provides a platform for the elderly to teach other people handicraft skills and helps them to sell their products online.

Ms Auyeung joined the Socialpreneur Incubation Course under the Lingnan University project. It encourages the development of social enterprises in Hong Kong, gerontechnology and marketing. She quickly drew inspiration from other socialpreneurs.

“I discovered that my social enterprise has to change every two years according to market demands. For example, fabric bags are popular among youngsters. While the elderly at Gatherly are equipped with blue-dye techniques, I make use of their skills to create products that match the market situation.”

University contribution

According to the Census & Statistics Department, in 2036, the proportion of the population aged 65 and over is projected to be 31%. To meet the needs of an ageing population, the Government is promoting gerontechnology, which combines gerontology and technology. It focuses on providing effective solutions to increase vitality and quality of life.

The Lingnan University’s three-year project aims to enhance public understanding of gerontechnology and support smart ageing socialpreneurship development. The project also covers studies with the goal of building a database for gerontech products and services as well as social innovation and startups. The overall vision is to offer policy recommendations to the industry and Government.

Lingnan University Asia-Pacific Institute of Ageing Studies Project Manager Chloe Siu said: “Most of the participating students are willing to think out-of-the-box, using their creativity and knowledge learnt from their courses and to echo the needs of the society. We are trying to facilitate different stakeholders and community partners to create a co-working atmosphere.”

The university has also built a 2,000 sq ft Gerontech-X Lab to display over 40 gerontech products catered to healthcare, dining, living and transport. Anyone interested can book an appointment for a free visit from November 28.

Do you know which main gases are contained in the composition of air? Under climate change and global warming, carbon dioxide ...

(University of Barcelona) The yellow-legged gull has a high ability to adapt to human activities and benefit from these as a food resource during all year. This is stated in a scientific article published in the journal Ecology and Evolution whose first author is the researcher Francisco Ramírez, from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona.

(Brown University) Strange spots scattered across the moon's nearside where bedrock is conspicuously exposed are evidence of seismic activity set in motion 4.3 billion years ago that could be ongoing today, the researchers say.

(University of California - Irvine) Cyanobacteria living in rocks in Chile's Atacama Desert extract water from the minerals they colonize and, in doing so, change the phase of the material from gypsum to anhydrite. Researchers at the University of California, Irvine and Johns Hopkins University gained verification of this process through experiments, and the work points to possible strategies for humans to stay hydrated in harsh environments.

(University of Chicago Press Journals) A recent study confirms that Mesoamerican priests ripped the hearts out of their still-living victims in three different ways. New forensic evidence, historic witness accounts and native representations now show that the most common form of native heart extraction was from beneath the rib cage, second was forceful chest penetration between two ribs and at mid-chest level between the nipples, and thirdly, a mid-chest opening of one single blow, extracting the heart from the front.

(University of Warwick) 21st century X-ray technology has allowed University of Warwick scientists to peer back through time at the production of the armour worn by the crew of Henry VIII's favoured warship, the Mary Rose.

(University of Maryland) Many historians have claimed the Justinianic Plague (c. 541-750 CE) killed half of the population of Byzantine (Eastern Roman) Empire. New historical research and mathematical modeling challenge the death rate and severity of this first plague pandemic, named for Emperor Justinian I.

(Bentham Science Publishers) This comprehensive review presented by researchers from K.S. Rangasamy College of Arts and Science, Tiruchengode, Tamil-Nadu, India, gives readers a brief overview of phytoconstituents, nutritional values and medicinal properties of the plant.

(Rutgers University) Algae in the oceans often steal genes from bacteria to gain beneficial attributes, such as the ability to tolerate stressful environments or break down carbohydrates for food, according to a Rutgers co-authored study.

Researchers have engineered bacteria to produce new versions of a potential antibiotic molecule, some with potent antimalarial properties.

What impact has the lockdown had on our mental health, and what determines how people cope with isolation?

(University of Stirling) Understanding the health impacts of the COVID-19 pandemic on people who use drugs in Scotland is the focus of a new University of Stirling study.

(University of Portsmouth) The first major UK study into victims of computer misuse crime has exposed the serious harm some victim's experience, as well as barriers to reporting such offences, receiving support, achieving justice and the precarious resources dedicated by the police to cybercrime.

(Purdue University) New environmentally friendly technologies promise to be 'game changers' in the rare earth metals field and enable the US to create a more stable and reliable domestic source of these essential metals. Purdue University patented extraction and purifying processes using ligand-assisted chromatography are shown to remove and purify such metals from coal ash, recycled magnets and raw ore safely, efficiently and with virtually no detrimental environmental impact.

(University of Sydney) Data centres and digital information processors are reaching their capacity limits and producing heat. Foundational work here on optical-acoustic microchips opens door to low-heat, low-energy, fast internet.

(Association for Computing Machinery) Today, the ACM Europe Technology Policy Committee (Europe TPC) of the world's largest society of computing professionals, the Association for Computing Machinery (ACM), has released detailed principles and practices for the development and deployment of 'contact tracing' technology intended to track and arrest the spread of COVID-19.

(University of Tsukuba) Researchers from the University of Tsukuba discovered that fish schools showed a significant change in behavior with varying school sizes. Using integrated information theory, they showed that a significant change in the interaction between the fish and the overall collective behavior occurred between three- and four-fish schools, including the emergence of leadership within the group. These findings help understand the dynamics of collective behavior.

Curtis Triplitt
Oct 1, 2006; 19:202-211
Pharmacy Update

Gregory A. Maynard
Oct 1, 2008; 21:241-247
Articles

Mary de Groot
Jan 1, 2010; 23:18-25
From Research to Practice

Robert Mayberry
Jul 1, 2010; 23:171-176
Feature Articles

Roger P. Austin
Jan 1, 2006; 19:13-16
Pharmacy Update

Emmy Suhl
Oct 1, 2006; 19:234-240
Articles

Russell E. Glasgow
Apr 1, 2001; 14:
Feature Articles

Daren R. Anderson
Apr 1, 2010; 23:97-105
Feature Articles

Five ways leaders can maintain a high level of trust during a crisis.

Management professors Adam Galinksy and Paul Ingram, together with Jonathan Laor ’21, CEO of Applicaster, advise on leadership during a crisis.

Director of Retail Studies Mark Cohen offers his view on the changes coming to large retailers, many of which had already seen declining sales and store closures before the pandemic hit.

Research Event

Event participants

James Harrison, Reader and Associate Professor, University of Warwick School of Law
Richard James, Evaluation Co-ordinator, Directorate-General for Trade European Commission
Jennifer Zerk, Associate Fellow, International Law Programme, Chatham House
Chair: Andrea Shemberg, Chair, Global Business Initiative on Human Rights

Invitation Only Research Event

β-Glucocerebrosidase (GBA) hydrolyzes glucosylceramide (GlcCer) to generate ceramide. Previously, we demonstrated that lysosomal GBA1 and nonlysosomal GBA2 possess not only GlcCer hydrolase activity, but also transglucosylation activity to transfer the glucose residue from GlcCer to cholesterol to form β-cholesterylglucoside (β-GlcChol) in vitro. β-GlcChol is a member of sterylglycosides present in diverse species. How GBA1 and GBA2 mediate β-GlcChol metabolism in the brain is unknown. Here, we purified and characterized sterylglycosides from rodent and fish brains. Although glucose is thought to be the sole carbohydrate component of sterylglycosides in vertebrates, structural analysis of rat brain sterylglycosides revealed the presence of galactosylated cholesterol (β-GalChol), in addition to β-GlcChol. Analyses of brain tissues from GBA2-deficient mice and GBA1- and/or GBA2-deficient Japanese rice fish (Oryzias latipes) revealed that GBA1 and GBA2 are responsible for β-GlcChol degradation and formation, respectively, and that both GBA1 and GBA2 are responsible for β-GalChol formation. Liquid chromatography–tandem MS revealed that β-GlcChol and β-GalChol are present throughout development from embryo to adult in the mouse brain. We found that β-GalChol expression depends on galactosylceramide (GalCer), and developmental onset of β-GalChol biosynthesis appeared to be during myelination. We also found that β-GlcChol and β-GalChol are secreted from neurons and glial cells in association with exosomes. In vitro enzyme assays confirmed that GBA1 and GBA2 have transgalactosylation activity to transfer the galactose residue from GalCer to cholesterol to form β-GalChol. This is the first report of the existence of β-GalChol in vertebrates and how β-GlcChol and β-GalChol are formed in the brain.

Pathogenic bacteria of the genera Mycobacterium and Corynebacterium cause severe human diseases such as tuberculosis (Mycobacterium tuberculosis) and diphtheria (Corynebacterium diphtheriae). The cells of these species are surrounded by protective cell walls rich in long-chain mycolic acids. These fatty acids are conjugated to the disaccharide trehalose on the cytoplasmic side of the bacterial cell membrane. They are then transported across the membrane to the periplasm where they act as donors for other reactions. We have previously shown that transient acetylation of the glycolipid trehalose monohydroxycorynomycolate (hTMCM) enables its efficient transport to the periplasm in Corynebacterium glutamicum and that acetylation is mediated by the membrane protein TmaT. Here, we show that a putative methyltransferase, encoded at the same genetic locus as TmaT, is also required for optimal hTMCM transport. Deletion of the C. glutamicum gene NCgl2764 (Rv0224c in M. tuberculosis) abolished acetyltrehalose monocorynomycolate (AcTMCM) synthesis, leading to accumulation of hTMCM in the inner membrane and delaying its conversion to trehalose dihydroxycorynomycolate (h2TDCM). Complementation with NCgl2764 normalized turnover of hTMCM to h2TDCM. In contrast, complementation with NCgl2764 derivatives mutated at residues essential for methyltransferase activity failed to rectify the defect, suggesting that NCgl2764/Rv0224c encodes a methyltransferase, designated here as MtrP. Comprehensive analyses of the individual mtrP and tmaT mutants and of a double mutant revealed strikingly similar changes across several lipid classes compared with WT bacteria. These findings indicate that both MtrP and TmaT have nonredundant roles in regulating AcTMCM synthesis, revealing additional complexity in the regulation of trehalose mycolate transport in the Corynebacterineae.

Xien Yu Chua
Apr 1, 2020; 19:730-743
Technological Innovation and Resources

Katrina Meyer
Apr 28, 2020; 0:R120.002034v1-mcp.R120.002034
Review

James A. Wilkins
Apr 13, 2020; 0:RA120.001944v1-mcp.RA120.001944
Research

Élie Lambert
May 1, 2020; 19:808-827
Research

Andreas Linden
Apr 24, 2020; 0:RA120.002028v1-mcp.RA120.002028
Research

Taewook Kang
Apr 7, 2020; 0:RA119.001882v1-mcp.RA119.001882
Research

Qingbo Shu
Apr 1, 2020; 19:672-689
Research

Karl A. T. Makepeace
Apr 1, 2020; 19:624-639
Research

Dorte B. Bekker-Jensen
Apr 1, 2020; 19:716-729
Technological Innovation and Resources