Comment

Comment by Dr. Krishna Kumari Challa on September 24, 2023 at 1:49pm

So why is it only mom's mtDNA that gets passed down?

One hypothesis has to do with the mitochondrial genome's relatively high mutation rate compared to the nuclear genome. Each cell in the body contains numerous mitochondria, which get separated into daughter cells the parent cell splits.

The way this split happens is fairly disorganized, all things considered, which means the daughter cells sometimes don't get enough mitochondria to meet their needs. Making the few mitochondria they do receieve work harder only makes splits and mutations more likely.

Because sperm cells rapidly churn through their energy trying to reach a human egg for fertilization, their mtDNA – if it did exist – would probably accumulate a bunch of mutations.

An egg cell, on the other hand, doesn't rely on its own mitochondria for energy. It saves those recipes for the future and instead sucks energy from the mitochondria of neighboring cells.

Eggs pass on really good mtDNA at least partly because they don't use mitochondria as a source of energy.

The findings do not explain why, in rare circumstances, scientists have found mtDNA transmission in some humans that looks as though it came from both the father and the mother. But it might help experts better understand some fertility disorders, which can be passed down through eggs or sperm. In recent years, scientists have started to find ways to target specific mutations in mitochondrial DNA so they aren't inherited by offspring. Worldwide, in fact, several children have been born with DNA from three different people, after their parents sought cutting-edge mitochondrial replacement therapy. The incredibly unique babies have nuclear DNA that derives from the fertilization of a sperm and an egg, like any other child, but their mitochondrial DNA comes from the egg of a separate female donor. "Maternal inheritance of mtDNA is a major paradigm that guides the existence and evolution of the vast majority of species," the authors of the recent study conclude, "however, the molecular basis of this phenomenon and its benefits have remained unclear."

For such a foundational part of life, it's incredible we don't know more about where our genes come from.

https://www.nature.com/articles/s41588-023-01505-9

Part 2

**

Comment by Dr. Krishna Kumari Challa on September 24, 2023 at 1:46pm

Why You Didn't Get Your Dad's Mitochondria

Virtually every animal on Earth can thank their mother for the energy that fuels each of their cells. The power is generated in a part of the cell known as the mitochondria, and this organelle is made entirely from a genetic recipe laid out in your mother's DNA.

A father's mitochondrial DNA, or mtDNA, plays no part. Yet the precise point at which dad's mitochondrial genes are given the heave-ho isn't a clear-cut story, with different studies supporting a breakdown in the egg's cytoplasm, and a severe edit in the sperm as it's being formed. A recent study that sequenced the genes in human sperm cells could detect no intact mtDNA before fertilization, lending support to an early chop. While each sperm cell contained about 100 mitochondria of its own, a team of researchers  found no trace of male mtDNA within the mitochondria. The sperm also lacked the transcription factors needed to maintain mtDNA. "We conclude," the authors write, "that the mature human spermatozoa are essentially devoid of mtDNA, consistent with maternal inheritance of the mitochondrial genome in mammals."

Of course, male sex cells still contribute nuclear DNA to their offspring, and the human nuclear genome is billions of times larger than the mitochondrial genome. Even still, mutations in the latter genome are associated with a diversity of diseases and aging processes, which suggests it is quite important for health and function.

So why is it only mom's mtDNA that gets passed down?

Part 1

Comment by Dr. Krishna Kumari Challa on September 24, 2023 at 1:27pm

Urban light pollution linked to smaller eyes in birds: Study

 The bright lights of big cities could be causing an evolutionary adaptation for smaller eyes in some birds, a new study indicates.

Researchers found that two common songbirds, the Northern Cardinal and Carolina Wren, that live year-round in the urban core of San Antonio, Texas, had eyes about 5% smaller than members of the same species from the less bright outskirts. Researchers found no eye-size difference for two species of migratory birds, the Painted Bunting and White-eyed Vireo, no matter which part of the city they lived in for most of the year.

The findings, published in Global Change Biology, have implications for conservation efforts amid the rapid decline of bird populations.

This study shows that residential birds may adapt over time to urban areas, but migratory birds are not adapting, probably because where they spend the winter—they are less likely to have the same human-caused light and noise pressures. It may make it more difficult for them to adjust to city life during the breeding season.

Todd M. Jones, Alfredo P. Llamas, Jennifer N. Phillips. Phenotypic signatures of urbanization? Resident, but not migratory, songbird eye size varies with urban‐associated light pollution levels. Global Change Biology, 2023; DOI: 10.1111/gcb.16935

Comment by Dr. Krishna Kumari Challa on September 23, 2023 at 9:22am

New research adds evidence to the benefits of ginger supplements for treating autoimmune diseases

New research has revealed a potentially important role ginger supplements can play in controlling inflammation for people living with autoimmune diseases.

The research published in JCI Insight focused on studying the impact of ginger supplementation on a type of white blood cell called the neutrophil. The study was especially interested in neutrophil extracellular trap (NET) formation, also known as NETosis, and what it may mean for controlling inflammation.

The study found ginger consumption by healthy individuals makes their neutrophils more resistant to NETosis. This is important because NETs are microscopic spider web-like structures that propel inflammation and clotting, which contribute to many autoimmune diseases, including lupus, antiphospholipid syndrome and rheumatoid arthritis.

There are a lot of diseases where neutrophils are abnormally overactive. Now researchers found that ginger can help to restrain NETosis, and this is important because it is a natural supplement that may be helpful to treat inflammation and symptoms for people with several different autoimmune diseases.

In a clinical trial, the researchers found that daily intake of a ginger supplement for seven days (20 mg of gingerols/day) by healthy volunteers boosted a chemical inside the neutrophil called cAMP. These high levels of cAMP then inhibited NETosis in response to various disease-relevant stimuli.

There are not a lot of natural supplements, or prescription medications for that matter, that are known to fight overactive neutrophils. Researchers think ginger may have a real ability to complement treatment programs that are already underway. The goal is to be more strategic and personalized in terms of helping to relieve people's symptoms.

 Ginger intake suppresses neutrophil extracellular trap formation in autoimmune mice and healthy humans, JCI Insight (2023).

https://insight.jci.org/articles/view/172011

Comment by Dr. Krishna Kumari Challa on September 23, 2023 at 9:09am

Brain sensitivity to insulin may be modulated by menstrual cycle

A combined team of diabetes specialists  has found evidence that suggests brain sensitivity to insulin may be modulated by the menstrual cycle in women.

In their study, reported in the journal Nature Metabolism, the group conducted a clinical trial involving monitoring the insulin levels of female volunteers.

Prior research has suggested that the presence of insulin in the brain can lead to changes in eating behavior, whole-body metabolism and fat storage. How this works is not well understood. Making things even murkier, as the researchers note, is that virtually all prior research in this area has involved testing the impact of insulin on the brains of men.

In this new effort, the research team sought to learn more about the impact of insulin on women's brains. To that end, they conducted a clinical trial that involved testing the impact of insulin on the brains of 11 female volunteers during two time periods; during their first day of ovulation, and just after they had ovulated.

To measure the impact of insulin on their brains, the volunteers underwent hyperinsulinemic-euglycemic clamps—a procedure that can be used to measureinsulin sensitivity. Some of the women were also given intranasal insulin doses during the procedure while others received a placebo. The researchers found that during the first day of ovulation, the brain was more sensitive to the insulin, but not during the days just after ovulation.

Next, the research team administered MRI scans to 15 different female volunteers to learn more about the impact of insulin on the hypothalamus during menstrual cycles. They found the same results—the women exhibited higher hypothalamus sensitivity to insulin just prior to the onset of ovulation but not afterward. The researchers suggest their findings explain why so many women experience hunger just prior to getting their period, why their metabolism slows and why weight gain is so much more likely. The researchers suggest that the female body reacts this way as a means of storing up energy to sustain a pregnancy, should it occur.

 Julia Hummel et al, Brain insulin action on peripheral insulin sensitivity in women depends on menstrual cycle phase, Nature Metabolism (2023). DOI: 10.1038/s42255-023-00869-w

Nils B. Kroemer, Metabolic tuning during the menstrual cycle, Nature Metabolism (2023). DOI: 10.1038/s42255-023-00867-y

Comment by Dr. Krishna Kumari Challa on September 22, 2023 at 9:12am

If you want to stop spam,

1. use a spam filter and block spammers—email and telecommunications providers often supply useful tools as part of their services
2. unsubscribe from any emails you no longer want to receive—even if you originally agreed to receive them
3. remove as much of your contact details from websites as you can and always restrict the sharing of your personal information (such as name, birth date, email address and mobile number) when you can—beware of pre-ticked boxes asking for your consent to receive marketing emails
4. install cybersecurity updates for your devices and software as you get them
5. always think twice about opening emails or clicking on links, especially for messages promising rewards or asking for personal information—if it looks too good to be true, it probably is
6. use multi-factor authentication to access online services so even if a scam compromises your login details, it will still be difficult for hackers to break into your accounts
7. report spam to your email and telecommunications providers.

Source: https://theconversation.com/why-do-i-get-so-much-spam-and-unwanted-...

Part 2

Comment by Dr. Krishna Kumari Challa on September 22, 2023 at 9:10am

Where do spammers get your details?

Each time you enter your email address or phone number into an e-commerce website, you may be handing it to spammers. But sometimes you may even receive spam from entities you don't recognize. That's because businesses will often transfer customers' contact information to related companies, or sell their data to third parties such as data brokers.

Some entities also use "address-harvesting" software to search the internet for electronic addresses that are captured in a database. The collector then uses these addresses directly, or sells them to others looking to send spam.

Most countries have prohibitions.

If the receiver consented to these types of messages, the prohibition does not apply. When you buy goods or services from a company, you will often see a request to click on a "yes" button to receive marketing promotions. Doing so means you have consented. On the other hand, if your phone or inbox are hit by commercial messages you haven't agreed to receive, that is a breach of the Spam Act by the sender. If you originally signed up to receive the messages, but then unsubscribed and the messages kept coming after five business days, that is also illegal. Senders must also include a functioning unsubscribe facility in every commercial message they send. Spammers can be penalized for breaches of the Spam Act.

It's worth noting that messages from political parties, registered charities and government bodies aren't prohibited—nor are messages from educational institutions to students and former students. So while you might consider these messages as "spam", they can legally be sent freely without consent. Factual messages (without marketing content) from businesses are also legal as long as they include accurate sender details and contact information.

Part 1

Comment by Dr. Krishna Kumari Challa on September 22, 2023 at 9:05am

Turning a cockroach into a cyborg without injuring it

Comment by Dr. Krishna Kumari Challa on September 22, 2023 at 8:56am

Smart speaker lets users mute different areas of a room

In virtual meetings, it's easy to keep people from talking over each other. Someone just hits mute. But for the most part, this ability doesn't translate easily to recording in-person gatherings. In a bustling cafe, there are no buttons to silence the table beside you.

The ability to locate and control sound—isolating one person talking from a specific location in a crowded room, for instance—has challenged researchers, especially without visual cues from cameras.

A team of researchers has developed a shape-changing smart speaker, which uses self-deploying microphones to divide rooms into speech zones and track the positions of individual speakers. With the help of the team's deep-learning algorithms, the system lets users mute certain areas or separate simultaneous conversations, even if two adjacent people have similar voices.

Like a fleet of Roombas, each about an inch in diameter, the microphones automatically deploy from and then return to a charging station. This allows the system to be moved between environments and set up automatically. In a conference room meeting, for instance, such a system might be deployed instead of a central microphone, allowing better control of in-room audio.

Creating Speech Zones Using Self-distributing Acoustic Swarms, Nature Communications (2023). DOI: 10.1038/s41467-023-40869-8. www.nature.com/articles/s41467-023-40869-8

Comment by Dr. Krishna Kumari Challa on September 22, 2023 at 8:38am

Regeneration across complete spinal cord injuries reverses paralysis

When the spinal cords of mice and humans are partially damaged, the initial paralysis is followed by the extensive, spontaneous recovery of motor function. However, after a complete spinal cord injury, this natural repair of the spinal cord doesn't occur and there is no recovery. Meaningful recovery after severe injuries requires strategies that promote the regeneration of nerve fibers, but the requisite conditions for these strategies to successfully restore motor function have remained elusive till recently.

Five years ago, some researchers demonstrated that nerve fibres can be regenerated across anatomically complete spinal cord injuries. But they also realized this wasn't enough to restore motor function, as the new fibers failed to connect to the right places on the other side of the lesion.

Now the scientists used state-of-the-art equipment to run in-depth analyses and identity which type of neuron is involved in natural spinal-cord repair after partial spinal cord injury.

Their  observations using single-cell nuclear RNA sequencing not only exposed the specific axons that must regenerate, but also revealed that these axons must reconnect to their natural targets to restore motor function.

Their discovery informed the design of a multipronged gene therapy. The scientists activated growth programs in the identified neurons in mice to regenerate their nerve fibers, upregulated specific proteins to support the neurons' growth through the lesion core, and administered guidance molecules to attract the regenerating nerve fibers to their natural targets below the injury.

Mice with anatomically complete spinal cord injuries regained the ability to walk, exhibiting gait patterns that resembled those quantified in mice that resumed walking naturally after partial injuries. This observation revealed a previously unknown condition for regenerative therapies to be successful in restoring motor function after neurotrauma.

Scientists now think a complete solution for treating spinal cord injury will require both approaches—gene therapy to regrow relevant nerve fibers, and spinal stimulation to maximize the ability of both these fibers and the spinal cord below the injury to produce movement.

While many obstacles must still be overcome before this gene therapy can be applied in humans, the scientists have taken the first steps towards developing the technology necessary to achieve this feat in the years to come.

Jordan W. Squair et al, Recovery of walking after paralysis by regenerating characterized neurons to their natural target region, Science (2023). DOI: 10.1126/science.adi6412. www.science.org/doi/10.1126/science.adi6412

• ‹ Previous
• 1
• …
• 406
• 407
• 408
• 409
• 410
• …
• 1152
• Next ›
• Page