BioQuakes

AP Biology class blog for discussing current research in Biology

Author: alectron

Aliens!!! – Not the Ones You’re Thinking of, Though…

In the article I came across, it discusses an “alien invasion” of sorts; however, this isn’t just any alien. In fact, this alien can be under your feet right now: non-native earthworms. Earthworms (not the alien kind) are described as “[m]ostly invisible and largely unappreciated” – these friendly creatures are invaluable to not only farmers and gardeners but you! In fact, these creatures support a lot of the agriculture you have grown to love and enjoy. “What makes them so helpful?” I’m sure you’re asking. Well, mainly, earthworm movement leaves an unimaginable amount of tunnels that allow air, water, and important nutrients to penetrate deep into the soil. On top of that, their waste doubles as a rich fertilizer!

Lumbricidae

Earthworms are far from always being sunshine and rainbows, though. When the wrong type of earthworm reaches the wrong type of ecosystem, chaos can easily ensue. This is what’s happening now all across North America with alien earthworms. Research has shown that, specifically in the northern broadleaf forests of the U.S. and Canada, alien earthworms have caused severe stress on local trees such as sugar maples – Acer saccharum – by altering the microhabitat of their soils. Even more, it is affecting local farmers as well. This microscopic impact can cause a snowball effect, allowing invasive species of plants to spread in an expedited manner. Isn’t it interesting and ironic that an organism known for actually improving soil can lead to poorer-quality crops and lower yield rates?

The article also spoke about specific research – drawing on extensive records spanning from 1891 to 2021, researchers compiled a database encompassing native and alien earthworm species. This dataset was augmented by another documenting interceptions of alien earthworms at U.S. borders from 1945 to 1975. Combined with new machine learning techniques, the team reconstructed the probable pathways of origin and spread of alien earthworm species. Their analysis revealed the presence of alien earthworms in a staggering 97% of soils studied across North America, with a higher (and extremely concerning) presence observed in the northern regions compared to the southern and western areas. 

Alien earthworms constituted 23% of the continent’s total of 308 earthworm species and comprised 12 of the 13 most widely distributed species. The article gave a fascinating contrast as well: only 8% of fish species, 6% of mammal species, and 2% of insects and arachnids in the U.S. are of alien origin. Lead author of the study, Jérôme Mathieu, an associate professor of ecology at the Sorbonne, emphasized that these proportions are likely to increase even more due to human activities, posing a significant threat to native earthworm populations, and to the future of our agricultural sector.

In terms of linking this back to our AP Bio course, it is easy to mention how we just learned about food webs, food chains, and trophic levels. We learned how delicate these intricate ecosystems are, and learned that when invasive and non-native species are introduced into an ecosystem, it (the ecosystem) becomes prone to collapse. Further, we can continue to apply this to the genetics unit that we are learning right now; as earthworms change the fundamental pH and nutrients in the soil, new adaptations will likely need to arise to, well, adapt to new conditions.

Who knew that such a small creature could have such a huge (and dangerous) impact on the ecosystems around us? Let me know what you think about it.

 

How HLA-B*15:01 Gives the Immune System a Head Start Against SARS-CoV-2

In the article I came across, it discusses how researchers have come across an ally within our immune system’s genetic coding. Human leukocyte antigen (HLA), otherwise known as the protein markers that signal the immune system, has been discovered to hold a secret that may revolutionize our approach to combating COVID-19. A specific mutation in the antigen, HLA-B*15:01, has emerged as a key player in asymptomatic infection of SARS-CoV-2. How did scientists stumble upon this discovery, and how does this mutation in the antigen actually allow infection without the presence of sickness?

Research conducted at the University of California, San Francisco (UCSF), led by Dr. Jill Hollenbach, didn’t hesitate to dive right into the genetic phenomenon, finding the very answers to those questions outlined above. Using a national marrow donor database and the COVID-19 Citizen Science Study (CSS) app, they tracked nearly 30,000 individuals through the first year of the pandemic, providing insights into genetic factors influencing COVID-19 infection and immune system-related reactions. In the end, the researchers revealed that a staggering 20% of asymptomatic individuals carried at least one copy of the mutated antigen HLA-B*15:01. Moreover, it was found that those with two copies were over eight times more likely to avoid falling ill.

SARS-CoV-2 (CDC-23312)

The secret of these genetic guardians is actually quite simple, and, through collaboration with researchers from La Trobe University in Australia, the UCSF team focused on the memory T-cell – a key element of the immune system’s ability to remember previous infections. Through their exploration, the researchers found that individuals with HLA-B*15:01, even without previous exposure to SARS-CoV-2, demonstrated T-cell responses to a specific viral peptide (the NQK-Q8 peptide). The researchers then concluded that exposure to a kind of seasonal coronavirus, which carries a strikingly similar peptide to SARS-CoV-2 called NQK-A8, enabled T cells in these individuals to quickly recognize Coronavirus and mount a faster, and, overall, more effective immune response. This led to minimal – if any – presence of symptoms within the study.  

Let’s link this research to what we’re currently delving into in our AP Biology class. In this unit in particular, we’ve been discussing and exploring the functions of cell signaling, as well as the ins and outs of the immune system. Thus, there are obvious associations between bodily response, antigens, and the immune system with SARS-CoV-2 to what we are currently uncovering in class. We learned how Helper-T cells kickstart the immune system by releasing cytokines that trigger mitosis in B – plasma B cells (which produce antigens) and memory B cells – and T cells – cytotoxic and memory. Knowing that this mutation in the antigen appears similar to SARS-CoV-2 NQK-A8 peptide, we can understand how this may have triggered an immune response in the past, and that a secondary infections would have been easier to take care of considering the memory B and T cells were already present in the body.

Can you see how it connects to what we’ve been learning in our AP Bio class? Isn’t our immune system fascinating? Let me know how you feel about this discovery!



 

 

Secrets of Plant Evolution: Unraveling the Genetic Symphony of Algal and Terrestrial Plant Life

          In the article I came across, it discusses the incredible diversity of plant life on Earth. Looking around, we see forms of plant life ranging anywhere from towering trees to microscopic algae. Where did these behemoths of plant life come from, and how exactly did plants come to evolve and dominate our terrestrial biomass? 

          Well, we are in luck. A group of international researchers, led by a team from the University of Göttingen (a research university located in Germany), conducted a fascinating study to understand the genetic networks at play in an algal relative of land plants, a “humble single-celled algae” called Mesotaenium endlicherianum — fresh water algae discovered in 1991. In an effort to understand how exactly plant terrestrialization — the colonization of land-based areas by aquatic plants — came to be, the researchers used a strain of Mesotaenium endlicherianum that had been preserved for over 25 years and exposed it to several light intensities and temperatures to gauge its resilience and genetic reaction under extreme conditions. In doing so, they revealed some remarkable insights – insights into the shared behavior of nearly 20,000 genes, and how such genetic mechanisms are common in both land plants and their algal relatives.

microscopic-view-of-microalgae

          By identifying hub genes, the researchers gained ​​invaluable information regarding not only the regulation of algal gene expression but, in conjunction with an evolutionary standpoint, that they are shared across more than 600 million years of plant and algal evolution. Armin Dadras, another PhD student at the University of Göttingen, explains an excellent simile when he says how It’s akin to finding the common threads in various songs where certain musical notes consistently blend in harmony. This insight aids in revealing enduring evolutionary patterns and sheds light on how specific genetic elements have remained unchanging across a diverse array of plant species, much like enduring melodies that reverberate across diverse music genres.

          Let’s link this research to what we’re currently delving into in our AP Bio class. So far, though we haven’t delved so deep into genetics, we have gained an understanding of the foundations. We’ve been discussing and exploring the functions of genetic material alongside our cell unit, where we learned that even in the tiniest of organisms, there’s an astonishing amount of genetic code at play. In humans, we have come to know that our DNA essentially holds the reins, dictating who we are and shaping our physical traits. After reading this article, we come to understand that in the world of plants, the story is no different. Just like it dictates our traits, DNA and genetics play a crucial role in determining where plants can thrive, in this case in the oceans or on land, and what environmental characteristics may trigger a migration. As we continue our journey into the wild waters of genetics, we will come to further understand the intricacies of this discovery.

          I’d love to hear your thoughts on this topic. Do you find the applications of this study as mind-blowing as I do? Can you see how it connects to what we’ve been learning and what we will soon learn in AP Bio? Share your views and let’s unravel the mysteries of life together!



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