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Internal clocks drive beta cell regeneration -- ScienceDaily

To explore the connection between internal biological clocks and beta cell regeneration, Charna Dibner's team first observed two groups of mice with only 20% beta cells remaining after targeted massive ablation. Mice in a first group were arrhythmic, whereas the control group had perfectly functional clocks. "The result was very clear: the mice bearing dysfunctional clocks were unable to regenerate their beta cells, and suffered from severe diabetes, while the control group animals had their beta cells regenerated; in just a few weeks, their diabetes was under control," says Volodymyr Petrenko, a researcher in Dr. Dibner's laboratory and the leading scientist in this study. By measuring the number of dividing beta cells across 24 hours, the scientists also noted that regeneration is significantly greater at night, when the mice are active.

60 minutes of endurance training is enough to shift body clock in mice -- ScienceDaily

This means that exercise is a cue for setting the clocks in muscles. The researchers determined this by studying mice that ran in different phases of the day: in the middle of their rest phase, an hour before starting their active phase, and in the middle of their active phase. Active and rest phases in mice are equivalent to day and night in humans. They then looked at how the amount of a primary clock protein changed over the course of multiple days following muscle contractions. Their results showed that depending on the timing of contractions the clocks shifted about an hour to either an earlier or later time and that this does not require circulating hormones or the central clock.

Disrupted circadian rhythms linked to later Parkinson's diagnoses: Researchers probe brain's 24-hour biological clock for neurodegenerative risks -- ScienceDaily

The scientists said their discovery of the link between circadian rhythms and Parkinson's -- a disease characterized by loss of control over movement, balance and other brain functions -- suggests these circadian disruptions may reflect neurodegenerative disease processes already affecting the brain's internal clock well before a Parkinson's diagnosis, and that they could be considered an early warning sign of the disease.

A role reversal for the function of certain circadian network neurons -- ScienceDaily

The researchers observed that fruit flies lacking dorsal termini were unable to properly synchronize their sleep/activity rhythms to daily temperature cycles. Previous research has shown that temperature changes play a role in regulating circadian rhythms. These new findings strongly suggest that dorsal medial termini neurons likely input (receive) signals from regions of the brain that track environmental temperature. "I have been curious for some time to know whether the structural plasticity that I characterized in clock neurons as a part of my graduate student work was an output mechanism for the clock to connect with downstream targets," said the study's first and co-senior author Maria Fernández, an assistant professor in the Department of Neuroscience and Behavior at Barnard College. "We were surprised to see that this site of plasticity seems to be involved in input, rather than output, pathways."

Gut reaction: How immunity ramps up against incoming threats -- ScienceDaily

Eating causes a hormone called VIP to kickstart the activity of immune cells in response to potentially incoming pathogens or 'bad' bacteria. The researchers also found that immunity increased at anticipated mealtimes indicating that maintaining regular eating patterns could be more important than previously thought. With the rise in conditions associated with chronic inflammation in the gut, such as irritable bowel and Crohn's disease, a better understanding of the early protective mechanisms governing gut health could help researchers to develop prevention strategies against unwanted inflammation and disease.

Learning from the bears -- ScienceDaily

A grizzly bear only knows three seasons during the year. Its time of activity starts between March and May. Around September the bear begins to eat large quantities of food. And sometime between November and January, it falls into hibernation. From a physiological point of view, this is the strangest time of all. The bear's metabolism and heart rate drop rapidly. It excretes neither urine nor feces. The amount of nitrogen in the blood increases drastically and the bear becomes resistant to the hormone insulin.

Before bed may be the best time to take blood pressure meds, study suggests | MinnPost

“The same medication ingested at different times of the day actually has different pharmacological properties, behaving like totally different medications,” explained Ramón Hermida, the study’s lead author and a chronobiologist at the University of Vigo in Spain, in an interview with NBC News.

Scientists discover skin keeps time independent of the brain -- ScienceDaily

But, he said, this study found that the skin actually expresses its own photoreceptors using a previously mysterious member of the opsin gene family, neuroposin. This means that skin can sense whether it is day or night even when it's cultured by itself in a dish. "If you simulate taking the cultured skin from Seattle to Japan (by simulating the light changes across time zones), the skin figures out that the time zone has changed and adapts to the new time zone within days because of neuropsin," said co-author Russ Van Gelder, professor and chair of ophthalmology at the UW School of Medicine. .

Chronobiology: Sleep and synaptic rhythms -- ScienceDaily

In the second study published in the same issue of Science the same group, in collaboration with a group from the University of Zürich (Steve Brown), has showed that synaptic protein abundance is also rhythmically shaped by sleep-wake cycles. In particular, they demonstrated that synaptic activity triggers the cycling production of proteins from messenger molecules that rhythmically accumulate at the synapses across the day. While protein production completely depends on wake-sleep cycles, messenger molecules travel and accumulate in the synapses predominantly in response to circadian mechanisms.

Molecule links weight gain to gut bacteria -- ScienceDaily

The study also found that microbes program these so-called circadian rhythms by activating a protein named histone deacetylase 3 (HDAC3), which is made by cells that line the gut. Those cells act as intermediaries between bacteria that aid in digestion of food and proteins that enable absorption of nutrients. The study, done in mice, revealed that HDAC3 turns on genes involved in the absorption of fat. They found that HDAC3 interacts with the biological clock machinery within the gut to refine the rhythmic ebb and flow of proteins that enhance absorption of fat. This regulation occurs in the daytime in humans, who eat during the day, and at night in mice, which eat at night. "The microbiome actually communicates with our metabolic machinery to make fat absorption more efficient. But when fat is overabundant, this communication can result in obesity. Whether the same thing is going on in other mammals, including humans, is the subject of future studies," added lead author Dr. Zheng Kuang, a postdoctoral fellow in the Hooper laboratory.

Biological clock influences immune response efficiency -- ScienceDaily

"Our study shows that T cells are more prone to be activated at certain times of the day. Identifying the mechanisms through which the biological clock modulates the T cell response will help us better understand the processes that regulate optimal T cell responses. This knowledge will contribute to improving vaccination strategies and cancer immune therapies," states Nathalie Labrecque, Professor at the Departments of Medicine and Microbiology, Infectious Diseases and Immunology at Université de Montréal.

Insulin under the influence of light -- ScienceDaily

To better assess the effect of light on tissue sensitivity to insulin, researchers measured insulin-induced glucose absorption. It turns out that a small disturbance in photic inputs (e.g. an hour of light exposure in the middle of the dark cycle, or light removal for 2 days) is enough to cause a negative effect. Indeed, increased or decreased light exposure can profoundly influence the sensitivity of tissues to insulin and the alteration, however minimal, of this mechanism is sufficient to significantly disrupt metabolic homeostasis. This would explain why people exposed to light at the wrong time -- workers in shift patterns, for example -- are more likely to develop metabolic diseases (e.g. diabetes).

Dead zones in circadian clocks -- ScienceDaily

One of the important properties of circadian clocks is the response to light signals, which enables organisms to become entrained to the 24-hour light-dark cycle on Earth. It has been shown that circadian clocks respond to light signals during the night, whereas they do not respond to such signals during the daytime. This holds true even when an organism is kept in complete darkness; a short light pulse does not change the time of the circadian clock when body time of the individual is at daytime. The time period in which the circadian clock is insensitive to light signals is referred to as the "dead zone." Previous studies have indicated that the presence of a dead zone improves the robustness of the clock. However, the mechanism underlying its generation is unclear.

How eating feeds into the body clock -- ScienceDaily

Dr Priya Crosby, a researcher at the MRC LMB and lead author on the study, highlighted: "Our data suggests that eating at the wrong times could have a major impact on our circadian rhythms. There is still work to do here, but paying particular attention to meal timing and light exposure is likely the best way to mitigate the adverse effects of shift-work. Even for those who work more traditional hours, being careful about when we eat is an important way to help maintain healthy body clocks, especially as we age."

Study links fluorescent lighting to inflammation and immune response - Neuroscience News

“In this report, we show genome-wide changes of gene expression patterns in skin, brain and liver for two commonly utilized fish experimental models (zebrafish and Japanese rice fish, also known as medaka), and a mammalian (mice), following exposure to 4,100 K ‘cool-white’ fluorescent light,” Walter said. “In spite of the extreme divergence of these animals (i.e., estimated divergence of mice and fish about 450 million years), and drastically different lifestyles (i.e., diurnal fish and nocturnal mice), the same highly conserved primary genetic response that involves activation of inflammation and immune pathways as part of an overall acute phase response was observed in the skin, brain and liver of all three animals. Follow-up studies to further define this response in mice are underway.”

Morning exercise for optimal metabolic impact

They found that a protein called hypoxia-inducible factor 1-alpha (HIF-1α) plays an important role and that it is activated by exercise in different ways depending on the time of day. HIF-1α is a transcription factor that is known to stimulate certain genes based on oxygen levels in tissue. “It makes sense that HIF-1α would be important here, but until now we didn’t know that its levels fluctuate based on the time of day,” Sassone-Corsi says. “This is a new finding.” Based on the work from the UC Irvine team, exercise seemed to have the most beneficial impact on the metabolism at the beginning of the active phase phase (equivalent to late morning in humans) compared with the resting phase (evening).

Two studies explore whether time of day can affect the body's response to exercise - Neuroscience News

The researchers also studied 12 humans and found similar effects. Overall, the people in the study had lower oxygen consumption while exercising in the evening compared with the morning; this translated to better exercise efficiency.

Fat cells work different 'shifts' throughout the day -- ScienceDaily

During this unique study seven participants underwent regulated sleep-wake cycles and meal times before entering the laboratory, where they maintained this routine for a further three days. Participants then experienced a 37- hour 'constant routine' during which time they did not experience daily changes in light-dark, feed-fast and sleep-wake cycles. Biopsies of fat tissue were taken at six hourly intervals and then followed by an analysis of gene expression. Researchers identified 727 genes in the fat tissue that express their own circadian rhythm, many carrying out key metabolic functions. A clear separation in gene rhythms was identified with approximately a third peaking in the morning and two thirds in the evening.

Exercise in Morning or Afternoon to Shift Your Body Clock Forward – Neuroscience News

This study found that exercising at 7 am or between 1 and 4 pm advanced the body clock to an earlier time, and exercising between 7 and10 pm delayed the body clock to a later time. Exercising between 1 and 4 am and at 10 am, however, had little effect on the body clock, and the phase-shifting effects of exercise did not differ based on age nor gender.

Disrupted circadian rhythms may drive anxiety and exacerbate brain disorders

"The studies presented today help deepen our understanding of why sleep is disrupted in so many patients," said press conference moderator Clifford Saper, MD, Ph.D., of Harvard Medical School, who's work focuses on integrated functions maintained by hypothalamus which includes the regulation of wake-sleep cycles. "They also suggest that sleep-focused therapies, such as treatments to regulate circadian rhythms, may be beneficial in the prevention or treatment of a vast array of diseases, including Alzheimer's disease and anxiety disorder and furthermore emphasize the critical need of good sleep for everyone's health."

Brain clock ticks differently in autism -- ScienceDaily

Sensory areas of the brain that receive input from the eyes, skin and muscles usually have shorter processing periods compared with higher-order areas that integrate information and control memory and decision-making. The new study, published in the journal eLife on February 5, shows that this hierarchy of intrinsic neural timescales is disrupted in autism. Atypical information processing in the brain is thought to underlie the repetitive behaviors and socio-communicational difficulties seen across the spectrum of autistic neurodevelopmental disorders (ASD), but this is one of the first indications that small-scale temporal dynamics could have an outsized effect.

Heavy drinking may change DNA, leading to increased craving for alcohol: Genetic vicious cycle may reinforce risky drinking behavior -- ScienceDaily

Scientists at Rutgers and Yale University School of Medicine focused on two genes implicated in the control of drinking behavior: PER2, which influences the body's biological clock, and POMC, which regulates our stress-response system. By comparing groups of moderate, binge and heavy drinkers, the researchers found that the two genes had changed in the binge and heavy drinkers through an alcohol-influenced gene modification process called methylation. The binge and heavy drinkers also showed reductions in gene expression, or the rate at which these genes create proteins. These changes increased with greater alcohol intake. Additionally, in an experiment, the drinkers viewed stress-related, neutral or alcohol-related images. They also were shown containers of beer and subsequently tasted beer, and their motivation to drink was evaluated. The result: alcohol-fueled changes in the genes of binge and heavy drinkers were associated with a greater desire for alcohol.

How Fasting Can Improve Overall Health - Neuroscience News

“The reorganization of gene regulation by fasting could prime the genome to a more permissive state to anticipate upcoming food intake and thereby drive a new rhythmic cycle of gene expression. In other words, fasting is able to essentially reprogram a variety of cellular responses. Therefore, optimal fasting in a timed manner would be strategic to positively affect cellular functions and ultimately benefiting health and protecting against aging-associated diseases.”

Stephen Colbert Shares His Struggle With Anxiety and Why He Stopped Taking Xanax | Entertainment Tonight

"I was actually medicated," he says. "I mean, in the most common, prosaic way. Xanax was just lovely. Y’know, for a while. And then I realized that the gears were still smoking. I just couldn’t hear them anymore. But I could feel them, I could feel the gearbox heating up and smoke pouring out of me, but I was no longer walking around a couch." "I had a bit of a nervous breakdown after I got married -- kind of panic attacks," he continues. "My wife would go off to work and she’d come home -- because I worked at night -- and I’d be walking around the couch. And she’s like, 'How was your day?' And I’d say, 'You’re looking at it.' Just tight circles around the couch."

Light pollution may cause insomnia in older adults: Artificial, outdoor light exposure at night is significantly associated with hypnotic drug prescription -- ScienceDaily

Results show that increasing nighttime levels of artificial, outdoor light exposure, stratified by quartile, were associated with an increased prevalence of hypnotic prescriptions and daily dose intake. Furthermore, older adults exposed to higher levels of artificial, outdoor light at night were more likely to use hypnotic drugs for longer periods or higher daily dosages. "This study observed a significant association between the intensity of outdoor, artificial, nighttime lighting and the prevalence of insomnia as indicated by hypnotic agent prescriptions for older adults in South Korea," said Kyoung-bok Min, PhD, an associate professor in the Department of Occupational and Environmental Medicine at Seoul National University College of Medicine in South Korea. "Our results are supportive data that outdoor, artificial, nighttime light could be linked to sleep deprivation among those while inside the house."

Cells decide when to divide based on their internal clocks -- ScienceDaily

Lead author of the study, Dr Bruno Martins from the University of Cambridge, said: "Cells born in the early part of the day grow to a smaller size before dividing again, because they seem to be in a 'rush' to divide before the end of the day. In contrast, cells born later in the day are in less of a 'rush', and therefore they grow to a bigger size, and avoid dividing in the period that normally corresponds to darkness at night." The team will next use their experimental results and the models developed to explain them to look at what molecules and genes are involved in this process and to explore its evolutionary function.