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Comment by Dr. Krishna Kumari Challa on March 15, 2024 at 11:35am

Researchers develop dual anti-tumour vaccine

a research team has discovered that exosomes derived from γδ-T cells not only have direct anti-tumor effects but also, when developed into a tumor vaccine, can effectively induce a tumor-specific immune response. The findings, which provide a new approach to cancer treatment, were published in the Journal of Extracellular Vesicles.

Exosomes are nanoscale particles secreted by cells, carrying various substances, such as lipids, proteins and nucleic acids, that play a crucial role in intercellular communication. Exosomes have been explored for developing tumor vaccines, as they can protect vaccine components from degradation, improve stability, extend the biological half-life, and enhance antigen uptake by antigen-presenting cells (APCs).

Previous studies focused on exosomes derived from tumor cells (TExos) and dendritic cells (DC-Exos) but found limitations in terms of safety and clinical efficacy.

In this study, the research team focused on exosomes derived from human γδ-T cells, a rare subset of T cells known for their direct anti-tumor activity and ability to enhance T-cell responses.

The research team discovered that γδ-T cell-derived exosomes (γδ-T-Exos) exhibited dual anti-tumor activities by carrying cytotoxic and immunostimulatory molecules that can directly kill tumor cells and stimulate the immune system.

They found that γδ-T-Exos has adjuvant effects, enhancing the expression of antigen-presenting and releasing molecules that promote inflammation, which improves the ability of the immune system to recognize and attack tumor cells.

Developing tumor vaccines by loading γδ-T-Exos with tumor-associated antigens proved more effective in promoting tumor-specific T-cell responses than using γδ-T-Exos alone. The vaccine strategy also retained direct anti-tumor effects and induced tumor cell death.

Intriguingly, the research showed that vaccines based on allogeneic γδ-T-Exos (derived from different individuals) exhibited similar preventive and therapeutic effects as vaccines based on autologous γδ-T-Exos (derived from the same individual) in mouse models. This suggests that this approach is suitable for centralized and standardized production. The vaccines have dual anti-tumor capabilities in effectively killing tumor cells and indirectly inducing a T-cell-mediated anti-tumor immune response, leading to better tumor control than existing vaccine strategies.

Xiwei Wang et al, Tumor vaccine based on extracellular vesicles derived from γδ‐T cells exerts dual antitumor activities, Journal of Extracellular Vesicles (2023). DOI: 10.1002/jev2.12360

Comment by Dr. Krishna Kumari Challa on March 15, 2024 at 11:19am

 Researchers observe how energy of single electron is tuned by surrounding atoms

Physicists  have choreographed the shift of a quantized electronic energy level with atomic oscillations faster than a trillionth of a second.

Throwing a ball into the air, one can transfer arbitrary energy to the ball such that it flies higher or lower. One of the oddities of quantum physics is that particles, e.g., electrons, can often only take on quantized energy values—as if the ball was leaping between specific heights, like steps of a ladder, rather than flying continuously.

Qubits and quantum computers as well as light-emitting quantum dots make use of this principle. However, electronic energy levels can be shifted by collisions with other electrons or atoms. Processes in the quantum world usually take place on atomic scales and are also incredibly fast.

Using a novel type of ultrafast microscope, a team of physicists has now succeeded in directly observing with atomic resolution on ultrafast timescales how the energy of a single electron is tuned by the vibrations of the surrounding atoms. Remarkably, they were also able to specifically control this process. Such discoveries could be crucial for the development of super-fast quantum technologies.

The physicists used an atomically thin material to investigate how a discrete energy level changes when this atomic layer moves up and down like the membrane of a drum. They observed this at a vacancy—the void left behind when an individual atom is removed.

Such atomically thin two-dimensional crystals, known for their versatile, customizable electronic properties, are particularly interesting for future nanoelectronics. Vacancies in a crystal are promising candidates for qubits, the elementary information carriers of quantum computers, as they have discrete electronic energy levels just like atoms.

The researchers found that they can change a discrete energy level of the defect by triggering a drum-like vibration of the atomically thin membrane: the atomic motion of the surrounding atoms shifts and thus controls the energy level of the vacancy.

The work establishes a new era in the study of the dynamics of atomically localized energy levels and their interaction with the environment. This discovery enables the local control of discrete energy levels in the most direct way. For instance, the motion of individual atoms could change the energy structure of a material and thus create new functionalities or specifically change the properties of light-emitting semiconductors and molecules.

Carmen Roelcke et al, Ultrafast atomic-scale scanning tunnelling spectroscopy of a single vacancy in a monolayer crystal. Nature Photonics. www.nature.com/articles/s41566-024-01390-6

Comment by Dr. Krishna Kumari Challa on March 15, 2024 at 10:07am

97% of sampled Antarctic seabirds found to have ingested microplastics

Anthropogenic plastic pollution is often experienced through evocative images of marine animals caught in floating debris, yet its reach is far more expansive. The polar regions of the Arctic and Antarctica are increasingly experiencing the impacts of plastic reaching floating ice and land, not solely as larger macroplastics (>5 cm), but as microplastics (0.1 µm—5 mm) and nanoplastics (<0.1 µm) that may be carried vast distances from their source or be ingested in more populated areas during seasonal migration.

A new review, published in Frontiers in Marine Science, has investigated the scale of this issue, particularly with respect to seabirds who call these glaciated regions home.

Across >1,100 samples, the researchers explored stomach contents, crop pouch near the throat for temporary food storage during foraging trips, guano (excrement mixture of food and metabolic waste) and regurgitated pellets of undigested food and other particles. Pellets formed the main component of the samples, followed by stomach contents and guano, while pouch contents were minimally present.

They found that 13 species of seabird inhabiting polar landscapes were reported to have ingested microplastics, including little auks, northern fulmars, glaucous gulls, thick-billed murres, white-chinned petrels, great shearwaters, sooty shearwaters, king penguins, Adélie penguins, chinstrap penguins, gentoo penguins, brown skuas and south polar skuas.

A total of 3,526 particles were extracted from these seabird samples, equating to at least 1 microplastic particle in 90% of Arctic samples and 97% for Antarctica. A median of 31.5 and 35, and average of 7.2 and 1.1, microplastic particles were found in each sample in the Arctic and Antarctica respectively. A maximum of 36 microplastic particles were found in a single bird.

Regarding plastic composition, 14 polymer types were identified, the dominant form being polyethylene, followed by polypropylene and polystyrene. These were predominantly present as fragments, derived from the breakdown of larger plastic objects. Such plastic polymer types can be sourced from items like plastic bags, food and drink containers and protective foam packaging.

The impact ingestion of plastic particles can have on seabirds includes blockage of their gastrointestinal tract, toxicity and oxidative stress, as well as triggering immune reactions. Additionally, it is not only direct ingestion of particles that is of concern, as microplastics have been found in krill, a food source for some penguins, highlighting the larger-scale issue in the ecosystem and trophic webs.

 Davide Taurozzi et al, Seabirds from the poles: microplastics pollution sentinels, Frontiers in Marine Science (2024). DOI: 10.3389/fmars.2024.1343617

Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 12:18pm

Temperature sensing is an essential function of all living organisms. Animals, including humans, use so-called transient receptor potential (TRP) channel molecules to sense temperature. These channel molecules are ion channel proteins that transport ions across cell membranes. They also act as temperature-sensing molecules because their function changes in response to temperature variation. By contrast, plants do not have temperature-sensing molecules such as TRP channels. Therefore, the mechanism by which plants sense temperature has been a mystery.

In this study, the research group focused attention on the fact that S. saman, which performs nyctinasty by folding its leaves at night and opening them in the morning, also folds its leaves when it rains. According to another report in 2018, nyctinasty in S. saman is regulated by SPORK2, an ion channel found in cells at the base of the leaf. This time, the research group found that this leaf folding is also triggered by temperature changes. They also found that SPORK2, like the TRP channel, changes its ion transport activity in response to temperature. Genes similar to SPORK2 (orthologs: genes derived from a common ancestral gene through species divergence) are found in other plants aside from S. saman.

Ion channels are proteins that form holes in the cell membrane through which ions are allowed to pass. The TRP channel creates holes for sodium and calcium ions, whereas SPORK2 generates holes for potassium ions. The activities of SPORK2 orthologs in Arabidopsis thaliana were also examined and they were found to be temperature-sensitive ion channels.

Crop production has been severely affected by climate change. Shedding light on the mechanisms by which plants adapt to temperature changes is an urgent issue for stable food production.

https://www.cell.com/current-biology/abstract/S0960-9822(23)01458-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982223014586%3Fshowall%3Dtrue

Part 2

Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 12:16pm

Researchers discover plant temperature sensor molecule: The Rain Tree folds its leaves in the rain

A research group led by Professor Minoru Ueda and Graduate Student Yuki Muraoka of the Graduate School of Science at Tohoku University announced that they have clarified the identity of temperature-sensitive ion channels in plants. Focusing on the phenomenon of the legume tree Samanea saman (also known as the Rain Tree), which folds its leaves when it rains, the researchers found that a decrease in leaf temperature triggers the folding movement. Aside from the temperature effect on leaf folding, the research group also found that the ion channel SPORK2, which is present in cells at the base of the leaf, functions as a sensor molecule to detect temperature changes. These findings are expected to lead to the elucidation of the temperature-sensing mechanism in plants and were published in the November 28 issue of the journal Current Biology.

 The phenomenon of rain tree leaves closing when it rains has led to the discovery of temperature sensors in plants.
Provided by Tohoku University

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Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 9:21am

Astronauts completed health screenings and a questionnaire about their headache history before the flight. During space flight, astronauts filled out a daily questionnaire for the first seven days and a weekly questionnaire each following week throughout their stay in the space station.

The astronauts reported 378 headaches in flight. Researchers found that 92% of astronauts experienced headaches during flight compared to just 38% of them experiencing headaches prior to flight.

Of the total headaches, 170, or 90%, were tension-type headache and 19, or 10%, were migraine.

Researchers also found that headaches were of a higher intensity and more likely to be migraine-like during the first week of space flight. During this time, 21 astronauts had one or more headaches for a total of 51 headaches. Of the 51 headaches, 39 were considered tension-type headaches and 12 were migraine-like or probable migraine.

In the three months after return to Earth, none of the astronauts reported any headaches.

This research does not prove that going into space causes headaches; it only shows an association. A limitation of the study was that astronauts  reported their own symptoms. 

https://www.neurology.org/doi/10.1212/WNL.0000000000209224

Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 9:18am

Astronauts experience 'space headaches'

Space travel and zero gravity can take a toll on the body. A new study has found that astronauts with no prior history of headaches may experience migraine and tension-type headaches during long-haul space flight, which includes more than 10 days in space. The study was published in Neurology.

Changes in gravity caused by space flight affect the function of many parts of the body, including the brain.

The vestibular system, which affects balance and posture, has to adapt to the conflict between the signals it is expecting to receive and the actual signals it receives in the absence of normal gravity. This can lead to space motion sickness in the first week, of which headache is the most frequently reported symptom. This new study shows that headaches also occur later in space flight and could be related to an increase in pressure within the skull.

The study involved 24 astronauts from the European Space Agency, the U.S. National Aeronautics and Space Administration (NASA) and the Japan Aerospace Exploration Agency. They were assigned to International Space Station expeditions for up to 26 weeks from November 2011 to June 2018.

Prior to the study, nine astronauts reported never having any headaches and three had a headache that interfered with daily activities in the last year. None of them had a history of recurrent headaches or had ever been diagnosed with migraine.

Of the total participants, 22 astronauts experienced one or more episodes of headache during a total of 3,596 days in space for all participants.

Part 1

Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 9:07am

With this platform, you can bust biofilms without surgically debriding infections, which can be necessary when using antibiotics. Plus, this method could treat patients if they are allergic to antibiotics or are infected by strains that are resistant to medication. The fact that this method is antibiotic-free is a huge bonus. 

The researchers assessed their strategy by applying the gold nanoparticles atop S. mutans-infected teeth from ex vivo rat jaws.

In a photoacoustic imaging test on the teeth, the nanoparticles emitted signals that came through loud and clear, allowing the team to see precisely where biofilms had taken up the dextran-coated particles on the teeth.

Then, to evaluate the particles' therapeutic effect, they irradiated the teeth with a laser. For comparison, they treated other infected teeth samples with the topical antiseptic chlorhexidine.

The team observed a stark contrast in the outcomes of the two treatments, with the photothermal therapy being nearly 100% effective at killing biofilms, while chlorhexidine did not significantly diminish the viability of bacteria.

The treatment method is especially fast for the oral infection.

Evaluations conducted on mice with open wounds in their skin, infected with Staphylococcus aureus, were similarly successful, as heat generated by nanoparticles greatly outperformed another antimicrobial agent called gentamicin. Here, the researchers also measured and noted a rise in temperature of 20°C localized to the biofilm, not causing any apparent damage to surrounding tissue.

 Maryam Hajfathalian et al, Theranostic gold-in-gold cage nanoparticles enable photothermal ablation and photoacoustic imaging in biofilm-associated infection models, Journal of Clinical Investigation (2023). DOI: 10.1172/JCI168485

Part 2

Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 9:07am

Sugar-coated gold nanoparticles can quickly eliminate bacterial infections, no antibiotics required

If left to their own devices, bacteria on our teeth or wounded skin can encase themselves in a slimy scaffolding, turning into what is called biofilm. Oral biofilms, also known as plaques, formed by bacteria such as Streptococcus mutans can cause significant tooth decay. Wound infections, which are commonly caused by Staphylococcus bacteria, can greatly delay the healing process. In either case, the densely packed network of proteins and carbohydrates within biofilms can prevent antibiotics from reaching microbes throughout the affected area.

But that isn't the extent of the issue posed by biofilms. Not only are they difficult to remove, but they are troublesome to discern in the first place.

These bacteria wreak havoc on our tissue and, being shielded from antibiotic medication by the slime, are difficult to dislodge. A new strategy may offer a simple way to break up the muck and destroy the bacteria.

This new research identified a solution to knock out both problems with one stone: gold.

Researchers have developed sugar-coated gold nanoparticles that they used to both image and destroy biofilms.

Gold is nontoxic and readily converts energy from light sources into heat, making it a prime candidate for photothermal therapy, a strategy that utilizes the heat from nanoparticles to kill nearby pathogens. In addition to generating heat, the nanoparticles emit detectable ultrasound waves in response to light, meaning that gold particles can be visualized using a technique called photoacoustic imaging.

In the new study, the authors encapsulated gold spheres within larger golden cage-shaped nanoparticles to optimize their response to light for both therapeutic and imaging purposes. To make the particles appealing to bacteria, they coated them in dextran, a carbohydrate that is a common building block of biofilms.

In a study published in the Journal of Clinical Investigation, the authors demonstrated the diagnostic and therapeutic potential of the nanoparticles on the teeth and wounded skin of rats and mice, eliminating the biofilms in as little as one minute and outperforming common antimicrobials. 

Part 1

Comment by Dr. Krishna Kumari Challa on March 14, 2024 at 7:21am

Study finds no persistent cough in four out of five individuals with tuberculosis in Africa and Asia

More than 80% of patients with tuberculosis, the world's most deadly infection, do not have a persistent cough, despite this being seen as a key symptom of the disease. The infection is predominantly transmitted by coughing, but probably also through simply breathing.

Researchers analyzed data on more than 600,000 individuals in Africa and Asia and found that 82.8% of those with tuberculosis had no persistent cough and 62.5% had no cough at all. These results are published today in The Lancet Infectious Diseases.

The  results indicate the probable reason why, despite huge efforts to diagnose and treat the disease, the tuberculosis (TB) burden across Africa and Asia is hardly declining.

A persistent cough is often the entry point for a diagnosis, but if 80% of those with TB don't have one, then it means that a diagnosis will happen later, possibly after the infection has already been transmitted to many others, or not at all.

 Prevalence of subclinical pulmonary tuberculosis in adults in community settings: an individual participant data meta-analysis, The Lancet Infectious Diseases (2024). DOI: 10.1016/S1473-3099(24)00011-2

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