Amazonian Tree With Human-Sized Leaves Finally Gets New Species Recognition
By Shreya Dasgupta
At the National Institute of Amazonian Research (INPA) in Manaus, Brazil, a framed exhibit of a massive dried leaf has been a local attraction for decades. But the complete identity of the tree it belongs to remained unresolved — until now.
Researchers have known that the tree is a species of Coccoloba, a genus of flowering plants that grow in the tropical forests of the Americas. Botanists from INPA first encountered an individual of the unknown Coccoloba tree in 1982 while surveying the Madeira River Basin in the Brazilian Amazon. They spotted more individuals of the plant over subsequent expeditions in the 1980s. But they couldn't pinpoint the species at the time. The individual trees weren't bearing any flowers or fruits then, parts that are essential to describing a plant species, and their leaves were too large to dehydrate, press and carry back to INPA. The researchers did take notes and photographs.
In 1993, botanists managed to finally collect two large leaves from a tree in the state of Rondônia, which they then framed for public viewing at INPA. "The species became locally famous, but due to the lack of reproductive material it could not be described as a new species for science," Rogério Gribel, a researcher at INPA, told Mongabay in an email.
It was more than a decade later, in 2005, that Gribel and his colleague, Carlos Alberto Cid Ferreira, collected some seeds and dying flowers from a tree in Jamari National Forest. Again, these materials weren't good enough to describe the plant species. So they sowed the seeds at the INPA campus, grew the seedlings, and waited. Their patience bore fruit 13 years later. Literally.
In 2018, one of the planted trees flourished and fruited, Gribel said, finally giving them the botanical material they needed to describe the new species.
"We are very happy and proud that after the long period of 'tracking' such a peculiar and relatively rare species, we have finally succeeded in obtaining the flowers and fruits that are the essential structures for describing a new species for science," he said.
Gribel and his colleagues, who described the species in a recent paper published in Acta Amazonica, have named it C. gigantifolia in reference to the plant's giant leaves.
The researchers say that C. gigantifolia, which grows to about 15 meters (49 feet) in height and has leaves that can reach 2.5 meters (8 feet) in length, likely has the largest known leaf among dicotyledonous plants — a large group of flowering plants that include sunflowers, hibiscus, tomatoes and roses. These plants have seeds that can be split into two identical halves, each forming the first two embryonic leaves of the seedling, and their leaves generally have branched veins. The seeds of monocotyledonous plants, by contrast, give out a single embryonic leaf and the grown plants' leaves have parallel veins, such as those of palm trees, grasses, orchids and bananas.
"Comparing leaf size between species is often difficult as there is a large individual variation in leaf size within the same species," Gribel said. "It is possible that this leadership of Coccoloba gigantifolia will be challenged in the future. For example, species of Gunnera, a genus of wide distribution worldwide, also exhibit huge leaves. But the Gunnera species are not arboreal."
Although C. gigantifolia has been known to the public and the scientific community for nearly four decades, describing it formally and giving it an official name was an essential step to complete.
"A known but undescribed species is like a person without a birth certificate or ID; it is like a person who does not formally have their identity recognized," Gribel said. "For example, in Brazil there is currently a major effort by the scientific community to catalog the national flora. Although known for many years, Coccoloba gigantifolia could not so far be added to the Brazilian Plant List by the scientists participating of this great initiative."
Without a formal identity, it's also difficult to assess the plant's conservation status. "Initiatives to prevent its extinction are also impaired if the plant has no scientific name," Gribel said. "Similarly, measures to regulate collection, trade, transport, planting, etc. depend on species recognition as a single taxonomic entity."
With the formal description in place, the researchers say that the species is likely rare and has a high risk of extinction. Individuals of C. gigantifolia have been recorded only from the Madeira River Basin in the Brazilian states of Amazonas and Rondônia — areas currently impacted by infrastructure projects such as hydroelectric dams, roads and expanding agriculture.
"The middle and low stretches of the Madeira River still have much of their forest conserved but deforestation has been growing rapidly in these areas, especially in northeastern Rondônia and southern Amazonas," Gribel said. "The Samuel Dam in the Jamari River (and possibly the Santo Antonio and Jirau Dams in the Madeira River) flooded tens of thousands of hectares of forests with Coccoloba gigantifolia and may have negatively affected the populations. The ongoing paving of the BR319 highway will increase deforestation throughout the Middle and Lower Madeira region."
Based on these threats, and on the findings that the species is rare and likely has disjointed populations occurring in a rapidly changing landscape, the authors have recommended listing the species as endangered on the IUCN Red List.
Researchers found Coccoloba gigantifolia at two spots close to the Madeira River and BR-319: near Manaus in Amazonas state (inset A) and Porto Velho in Rondônia (inset B). Satellite data from the University of Maryland show that these areas have experienced heavy deforestation over the past couple decades. Source: GLAD/UMD, accessed through Global Forest Watch.
Zooming in on the northern site (inset A on the map above) reveals areas of recent forest loss encroaching on the approximate locations where researchers recorded the newly described species. Source: GLAD/UMD, accessed through Global Forest Watch; Melo et al., 2019.
Coccoloba gigantifolia was also recorded in two spots near Porto Velho. The region is part of the so-called "arc of deforestation," where agricultural expansion has razed much of the rainforest along the underbelly of the Brazilian Amazon. The northernmost of these sites is in an unprotected area that was flooded by the Samuel hydroelectric dam in the 1990s. The other site is located within Jamari National Forest near a wetland (blue inset) that is showing signs of forest loss. Sources: GLAD/UMD, accessed through Global Forest Watch; Melo et al., 2019.
Satellite imagery shows water levels of the wetland near where Coccoloba gigantifolia was found in Jamari National Forest were far lower in October 2019 than in years past. Source: Planet Labs.
Reposted with permission from Mongabay.
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By Ana Maldonado-Contreras
- Your gut is home to trillions of bacteria that are vital for keeping you healthy.
- Some of these microbes help to regulate the immune system.
- New research, which has not yet been peer-reviewed, shows the presence of certain bacteria in the gut may reveal which people are more vulnerable to a more severe case of COVID-19.
You may not know it, but you have an army of microbes living inside of you that are essential for fighting off threats, including the virus that causes COVID-19.
How Do Resident Bacteria Keep You Healthy?<p>Our immune defense is part of a complex biological response against harmful pathogens, such as viruses or bacteria. However, because our bodies are inhabited by trillions of mostly beneficial bacteria, virus and fungi, activation of our immune response is tightly regulated to distinguish between harmful and helpful microbes.</p><p>Our bacteria are spectacular companions diligently helping prime our immune system defenses to combat infections. A seminal study found that mice treated with antibiotics that eliminate bacteria in the gut exhibited an impaired immune response. These animals had low counts of virus-fighting white blood cells, weak antibody responses and poor production of a protein that is vital for <a href="https://doi.org/10.1073/pnas.1019378108" target="_blank">combating viral infection and modulating the immune response</a>.</p><p><a href="https://doi.org/10.1371/journal.pone.0184976" target="_blank" rel="noopener noreferrer">In another study</a>, mice were fed <em>Lactobacillus</em> bacteria, commonly used as probiotic in fermented food. These microbes reduced the severity of influenza infection. The <em>Lactobacillus</em>-treated mice did not lose weight and had only mild lung damage compared with untreated mice. Similarly, others have found that treatment of mice with <em>Lactobacillus</em> protects against different <a href="https://doi.org/10.1038/srep04638" target="_blank" rel="noopener noreferrer">subtypes of</a> <a href="https://doi.org/10.1038/s41598-017-17487-8" target="_blank" rel="noopener noreferrer">influenza</a> <a href="https://doi.org/10.1371/journal.ppat.1008072" target="_blank" rel="noopener noreferrer">virus</a> and human respiratory syncytial virus – the <a href="https://doi.org/10.1038/s41598-019-39602-7" target="_blank" rel="noopener noreferrer">major cause of viral bronchiolitis and pneumonia in children</a>.</p>
Chronic Disease and Microbes<p>Patients with chronic illnesses including Type 2 diabetes, obesity and cardiovascular disease exhibit a hyperactive immune system that fails to recognize a harmless stimulus and is linked to an altered gut microbiome.</p><p>In these chronic diseases, the gut microbiome lacks bacteria that activate <a href="https://doi.org/10.1126/science.1198469" target="_blank" rel="noopener noreferrer">immune cells</a> that block the response against harmless bacteria in our guts. Such alteration of the gut microbiome is also observed in <a href="https://doi.org/10.1073/pnas.1002601107" target="_blank" rel="noopener noreferrer">babies delivered by cesarean section</a>, individuals consuming a poor <a href="https://doi.org/10.1038/nature12820" target="_blank" rel="noopener noreferrer">diet</a> and the <a href="https://doi.org/10.1038/nature11053" target="_blank" rel="noopener noreferrer">elderly</a>.</p><p>In the U.S., 117 million individuals – about half the adult population – <a href="https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/" target="_blank" rel="noopener noreferrer">suffer from Type 2 diabetes, obesity, cardiovascular disease or a combination of them</a>. That suggests that half of American adults carry a faulty microbiome army.</p><p>Research in my laboratory focuses on identifying gut bacteria that are critical for creating a balanced immune system, which fights life-threatening bacterial and viral infections, while tolerating the beneficial bacteria in and on us.</p><p>Given that diet affects the diversity of bacteria in the gut, <a href="https://www.umassmed.edu/nutrition/melody-trial-info/" target="_blank" rel="noopener noreferrer">my lab studies show how diet can be used</a> as a therapy for chronic diseases. Using different foods, people can shift their gut microbiome to one that boosts a healthy immune response.</p><p>A fraction of patients infected with SARS-CoV-2, the virus that causes COVID-19 disease, develop severe complications that require hospitalization in intensive care units. What do many of those patients have in common? <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm" target="_blank" rel="noopener noreferrer">Old age</a> and chronic diet-related diseases like obesity, Type 2 diabetes and cardiovascular disease.</p><p><a href="http://doi.org/10.1016/j.jada.2008.12.019" target="_blank" rel="noopener noreferrer">Black and Latinx people are disproportionately affected by obesity, Type 2 diabetes and cardiovascular disease</a>, all of which are linked to poor nutrition. Thus, it is not a coincidence that <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6933e1.htm" target="_blank" rel="noopener noreferrer">these groups have suffered more deaths from COVID-19</a> compared with whites. This is the case not only in the U.S. but also <a href="https://www.washingtonpost.com/world/europe/blacks-in-britain-are-four-times-as-likely-to-die-of-coronavirus-as-whites-data-show/2020/05/07/2dc76710-9067-11ea-9322-a29e75effc93_story.html" target="_blank" rel="noopener noreferrer">in Britain</a>.</p>
Discovering Microbes That Predict COVID-19 Severity<p>The COVID-19 pandemic has inspired me to shift my research and explore the role of the gut microbiome in the overly aggressive immune response against SARS-CoV-2 infection.</p><p>My colleagues and I have hypothesized that critically ill SARS-CoV-2 patients with conditions like obesity, Type 2 diabetes and cardiovascular disease exhibit an altered gut microbiome that aggravates <a href="https://theconversation.com/exercise-may-help-reduce-risk-of-deadly-covid-19-complication-ards-136922" target="_blank" rel="noopener noreferrer">acute respiratory distress syndrome</a>.</p><p>Acute respiratory distress syndrome, a life-threatening lung injury, in SARS-CoV-2 patients is thought to develop from a <a href="http://doi.org/10.1016/j.cytogfr.2020.05.003" target="_blank" rel="noopener noreferrer">fatal overreaction of the immune response</a> called a <a href="https://theconversation.com/blocking-the-deadly-cytokine-storm-is-a-vital-weapon-for-treating-covid-19-137690" target="_blank" rel="noopener noreferrer">cytokine storm</a> <a href="http://doi.org/10.1016/S2213-2600(20)30216-2" target="_blank" rel="noopener noreferrer">that causes an uncontrolled flood</a> <a href="http://doi.org/10.1016/S2213-2600(20)30216-2" target="_blank" rel="noopener noreferrer">of immune cells into the lungs</a>. In these patients, their own uncontrolled inflammatory immune response, rather than the virus itself, causes the <a href="http://doi.org/10.1007/s00134-020-05991-x" target="_blank" rel="noopener noreferrer">severe lung injury and multiorgan failures</a> that lead to death.</p><p>Several studies <a href="https://doi.org/10.1016/j.trsl.2020.08.004" target="_blank" rel="noopener noreferrer">described in one recent review</a> have identified an altered gut microbiome in patients with COVID-19. However, identification of specific bacteria within the microbiome that could predict COVID-19 severity is lacking.</p><p>To address this question, my colleagues and I recruited COVID-19 hospitalized patients with severe and moderate symptoms. We collected stool and saliva samples to determine whether bacteria within the gut and oral microbiome could predict COVID-19 severity. The identification of microbiome markers that can predict the clinical outcomes of COVID-19 disease is key to help prioritize patients needing urgent treatment.</p><p><a href="https://doi.org/10.1101/2021.01.05.20249061" target="_blank" rel="noopener noreferrer">We demonstrated</a>, in a paper which has not yet been peer reviewed, that the composition of the gut microbiome is the strongest predictor of COVID-19 severity compared to patient's clinical characteristics commonly used to do so. Specifically, we identified that the presence of a bacterium in the stool – called <em>Enterococcus faecalis</em>– was a robust predictor of COVID-19 severity. Not surprisingly, <em>Enterococcus faecalis</em> has been associated with <a href="https://doi.org/10.1053/j.gastro.2011.05.035" target="_blank" rel="noopener noreferrer">chronic</a> <a href="https://doi.org/10.1016/S0002-9440(10)61172-8" target="_blank" rel="noopener noreferrer">inflammation</a>.</p><p><em>Enterococcus faecalis</em> collected from feces can be grown outside of the body in clinical laboratories. Thus, an <em>E. faecalis</em> test might be a cost-effective, rapid and relatively easy way to identify patients who are likely to require more supportive care and therapeutic interventions to improve their chances of survival.</p><p>But it is not yet clear from our research what is the contribution of the altered microbiome in the immune response to SARS-CoV-2 infection. A recent study has shown that <a href="https://doi.org/10.1101/2020.12.11.416180" target="_blank" rel="noopener noreferrer">SARS-CoV-2 infection triggers an imbalance in immune cells</a> called <a href="https://doi.org/10.1111/imr.12170" target="_blank" rel="noopener noreferrer">T regulatory cells that are critical to immune balance</a>.</p><p>Bacteria from the gut microbiome are responsible for the <a href="https://doi.org/10.7554/eLife.30916.001" target="_blank" rel="noopener noreferrer">proper activation</a> <a href="https://doi.org/10.1126/science.1198469" target="_blank" rel="noopener noreferrer">of those T-regulatory</a> <a href="https://doi.org/10.1038/nri.2016.36" target="_blank" rel="noopener noreferrer">cells</a>. Thus, researchers like me need to take repeated patient stool, saliva and blood samples over a longer time frame to learn how the altered microbiome observed in COVID-19 patients can modulate COVID-19 disease severity, perhaps by altering the development of the T-regulatory cells.</p><p>As a Latina scientist investigating interactions between diet, microbiome and immunity, I must stress the importance of better policies to improve access to healthy foods, which lead to a healthier microbiome. It is also important to design culturally sensitive dietary interventions for Black and Latinx communities. While a good-quality diet might not prevent SARS-CoV-2 infection, it can treat the underlying conditions related to its severity.</p><p><em><a href="https://theconversation.com/profiles/ana-maldonado-contreras-1152969" target="_blank">Ana Maldonado-Contreras</a> is an assistant professor of Microbiology and Physiological Systems at the University of Massachusetts Medical School.</em></p><p><em>Disclosure statement: Ana Maldonado-Contreras receives funding from The Helmsley Charitable Trust and her work has been supported by the American Gastroenterological Association. She received The Charles A. King Trust Postdoctoral Research Fellowship. She is also member of the Diversity Committee of the American Gastroenterological Association.</em></p><p><em style="">Reposted with permission from <a href="https://theconversation.com/a-healthy-microbiome-builds-a-strong-immune-system-that-could-help-defeat-covid-19-145668" target="_blank" rel="noopener noreferrer" style="">The Conversation</a>. </em></p>
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