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Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 11:36am

Why wavy wounds heal faster than straight wounds

Wavy wounds heal faster than straight wounds because shapes influence cell movements, a team of researchers has found.

Scientists observed the motion of cells and found that those near wavy shaped wounds moved in a swirling manner while cells near straight wounds moved in straight lines, traveling parallel to the edges.

The team concluded that the swirling or vortex-like movement is crucial to gap bridging, in which cells build bridges to heal damaged tissues, and which accelerates the wound healing process in wavy wounds.

This is the first time that the relationship between gap bridging, and the speed of wound healing has been determined. The scientists said their findings open the door to the development of more effective strategies to speed up wound healing, for better wound management, tissue repair, and plastic surgery.

An essential component of wound healing is re-epithelialization, a process in which the epithelial cell—a type of cell found on the skin—moves to form a bridge between the wound and the skin, closing its gap.

While previous studies have found that zig zag wounds healed faster than straight wounds, little is known about how different wound curvatures (shape) and wound sizes influence healing efficiency, nor about the mechanism of re-epithelialization.

To investigate, the NTU scientists prepared synthetic wounds with a range of widths (30 micrometers to 100 micrometers) and curvatures (radius of curvature: 30 micrometers, 75 micrometers, 150 micrometers and straight line) to learn how cells moved to close wound gaps in different circumstances.

Using particle image velocimetry—an optical measurement technique for fluid flow—researchers found that wavy wounds induced more complex collective cell movements, such as a swirly, vortex-like motion. By contrast in a straight wound, cells moved parallel to the wound front, moving in straight lines like a marching band.

Wavy wounds heal nearly five times faster

The  team also observed the healing progress of the synthetic wounds over a period of 64 hours and found that the healing efficiency of wavy gaps—measured by the percentage area covered by the cells over time—is nearly five times faster than straight gaps.

 Hongmei Xu et al, Geometry-mediated bridging drives nonadhesive stripe wound healing, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2221040120

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 9:50am

How superbug A. baumannii survives metal stress and resists antibiotics

The deadly hospital pathogen Acinetobacter baumannii can live for a year on a hospital wall without food and water. Then, when it infects a vulnerable patient, it resists antibiotics as well as the body's built-in infection-fighting response. The World Health Organization (WHO) recognizes it as one of the three top pathogens in critical need of new antibiotic therapies.

Now a team of international researchers have discovered how the superbug can survive harsh environments and then rebound, causing deadly infections. They have found a single protein that acts as a master regulator. When the protein is damaged, the bug loses its superpowers allowing it to be controlled, in a lab setting. The research is published in Nucleic Acids Research.

During infection our cells fight back by either flooding or starving bacteria of essential metals such as copper and zinc. A. baumannii has strong drug pumps that push antibiotics, metals and other threats out of the cell.

By studying how this bug deals with infection stresses,  researchers have found an important uncharacterized regulatory protein (DksA). When scientists disrupted this protein, it lead to changes in about 20 percent of the bug's genome and breaks its pumping system.

Ram P Maharjan et al, DksA is a conserved master regulator of stress response in Acinetobacter baumannii, Nucleic Acids Research (2023). DOI: 10.1093/nar/gkad341

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 9:36am

In its original habitat in African tropical forests on nutrient-poor soils, Triphyophyllum peltatum can thus avoid the threat of malnutrition by forming traps and accessing the important nutritional element through digestion of its insect prey. "These new findings are a breakthrough because they allow future molecular analyses that will help understand the origins of carnivory," the scientists say.

Traud Winkelmann et al, Carnivory on demand: phosphorus deficiency induces glandular leaves in the African liana Triphyophyllum peltatum, New Phytologist (2023). DOI: 10.1111/nph.18960

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 9:36am

Deficiency causes rare tropical plant to develop appetite for meat

Under certain circumstances, a rare tropical plant develops into a carnivore. A research team  has now deciphered the mechanism responsible for this.

Triphyophyllum peltatum is a unique plant. Native to the tropics of West Africa, the liana species is of great interest for medical and pharmaceutical research due to its constituents: In the laboratory, these show promising medically useful activities against pancreatic cancer and leukemia cells, among others, as well as against the pathogens that cause malaria and other diseases.

However, the plant species is also interesting from a botanical perspective: Triphyophyllum peltatum is the only known plant in the world that can become a carnivore under certain circumstances. Its menu then includes small insects, which it captures with the help of adhesive traps in the form of secretion drops and digests with lytic enzymes synthesized.

A high flexibility can be observed in the leaves of the plant, which develop three different types depending on the stage of development. While in the juvenile phase simple leaves are initially formed, later so-called "trap leaves" can be formed, which carry a large number of adhesive traps. When these trap leaves have served their purpose, the plant either forms normal leaves again or—if the plant has entered the liana stage—leaves with two hooks at the tip as a climbing support.

As far as the expression of leaf identity is concerned, Triphyophyllum peltatum shows a high degree of flexibility: the developmental stages can vary in length, and the carnivorous stage can be omitted completely or made up for at a later stage. Thus, the plant seems to adapt to the prevailing conditions of its habitat.

The trigger that turns the plant into a carnivore was previously unknown. One reason for this was the fact that Triphyophyllum peltatum was considered very difficult to cultivate and therefore the formation of trap leaves was difficult to study experimentally. This problem has now been solved by scientists now.

But what is even more significant is that with the help of these plants, the research team was able to identify the factor that triggers the transformation to the carnivore lifestyle. The team has now published the results of this research in the current issue of the journal New Phytologist.

Researchers exposed the plant to different stress factors, including deficiencies of various nutrients, and studied how it responded to each. Only in one case were we able to observe the formation of traps: in the case of a lack of phosphorus. In fact, a greatly reduced supply of phosphorus is already sufficient to trigger the development into a carnivorous plant, according to the scientists.

Part 1

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 9:31am

This is made of plants. Why do we call it “meat”?

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 8:33am

Earlier  it was found that intestinal bacteria in centenarians produced unique bile acids that could help keep infections at bay. Other researchers have found that bacteriophages—or viruses that infect bacteria—had an effect on cognition and memory in mice.

 Now the researchers compared the viromes of young adults over 18, older adults over 60, and centenarians aged 100 and over. 

 In centenarians, the team found not only more diverse bacteria and viruses, but also more viruses in the lytic life cycle, during which viruses are active and burst and kill the bacteria they infect—a phase that is more common in infants than adults. At least a quarter of the viruses found in centenarians encoded genes that support key stages of sulfate metabolism. The researchers think this could help sustain the integrity of the mucosal barrier, a highly selective collection of tightly-bound cells that allows the body to absorb nutrients in the gut while keeping bacteria and toxins at bay.

Joachim Johansen et al, Centenarians have a diverse gut virome with the potential to modulate metabolism and promote healthy lifespan, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01370-6

Part 2

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 8:31am

Viruses in the guts of centenarians may help them resist pathogens

New research suggests that centenarians—people who live to be at least 100—have a diverse collection of viruses in their gut that could help protect them from infectious diseases. The findings, published May 15 in Nature Microbiology, shed light on some of the biological pathways that may help centenarians live long, healthy lives.

In the study, researchers analyzed the viromes—or viral genomes—from 195 individuals from Japan and Sardinia. They found that centenarians  had a greater diversity of bacteria and viruses in their guts.

They also found that viruses found in centenarians increased the ability of the healthy gut bacteria to break down sulfate, which could help preserve the gut's ability to fight bacterial infections.

The study adds to a growing body of evidence showing that the interactions between bacteria, viruses, and fungi in the gut play an important role in preventing age-related conditions.

This snapshot of how the virome interacts with gut microbiomes could tell us about how microbial and viral ecology evolves over the lifetime of a person. This offers an important starting point for uncovering the mechanisms behind how the gut ecosystem maintains health.

Part 1

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 8:28am

Metastatic spread involves the detachment of tumor cells from a primary tumor, colonization of secondary tissue and growth in a hostile environment. Advanced metastatic tumors are often able to withstand aggressive treatment regimens and represent the leading cause of cancer-associated death.

 The researchers found that the differences are highly dependent on the type of tumor. In some types of tumors, such as pancreatic cancer, the genomic differences between primary and metastatic tumors are subtle. While in others, such as prostate, thyroid and some subtypes of breast cancer, there are very important genomic differences.

In addition, the exhaustive analysis has allowed the researchers to identify recurrent genomic patterns in metastatic tumors such as the presence of high genomic instability, greater enrichment of structural genomic alterations versus point mutations, and the presence of genomic alterations associated with the acquisition of resistance to treatment. However, hardly any driver alterations exclusively associated with the metastatic process could be identified.

Francisco Martínez-Jiménez et al, Pan-cancer whole-genome comparison of primary and metastatic solid tumours, Nature (2023). DOI: 10.1038/s41586-023-06054-z

Francisco Martínez-Jiménez et al, Genetic immune escape landscape in primary and metastatic cancer, Nature Genetics (2023). DOI: 10.1038/s41588-023-01367-1

Part 3

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Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 8:26am

The paper published in Nature describes the overall genomic differences found when comparing primary and metastatic tumors and highlights the fact that the differences are highly dependent on the type of cancer studied, as well as the tumor's exposure to previous anti-tumor treatments.

One could state that this work confirms many observations that were previously done in cancer type-specific studies. However, the pan-cancer nature of the current study demonstrates which processes and mechanisms are shared between tumor types and also quantifies their prevalence per tumor type. Such a systematic analysis and comparison from a genome-wide perspective has never been performed before.

The second study, published in parallel in the journal Nature Genetics, presents an analysis of the genomic alterations that allow tumors to escape the immune system, as well as a comparison of their prevalence in primary and metastatic tumors.

The researchers found that the prevalence of genetic immune escape is highly variable between tumor types and that in certain tumor types only a single mechanism is present, while in others various processes were affected. Furthermore, they showed that there are not many differences between primary and metastatic tumors, indicating that immune evasion is a characteristic that is acquired relatively early in tumor development.

This is the first time a complete tumor genome-wide sequencing dataset has been generated for primary and metastatic tumors of this magnitude. These data are public and available for research, providing a new global resource for further research into the biology and evolution of cancer, as well as the development of new therapies to combat the disease.

Part 2

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 8:25am

Unique insights into differences between primary and metastatic cancer by large-scale DNA data analyses

Cancer is caused by DNA changes that cause a cell to gradually change from benign to malignant. This can lead to metastases in other parts of the body. By analyzing the DNA data of more than 7,000 patients, the researchers show that there are major differences between primary and metastatic cancer and that there are also tumor types in which the primary tumor and the metastasis hardly differ from one another. By studying the types of DNA changes and the consequences of the changes, important insights into the underlying biological processes were obtained.

Researchers have mapped the DNA changes of the 23 most common tumor types. They have studied the differences in genetic characteristics between the source of the cancer, the primary tumor, and metastatic tumors.

Unique collections of whole genome sequencing data from tumors were used. This enabled the researchers to study in great detail which changes in the tumor had occurred during and after the tumor had developed. The researchers have harmonized and systematically compared the world's largest publicly available data sets of primary tumors (from the international PCAWG consortium with information from ~2,800 patients) and metastatic tumors (Hartwig Medical Database, ~4,400 patients). The results of this research were published May 10 in the journals Nature and Nature Genetics.

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