Termite Gut Microbes could Aid Biofuel Production

From the ACS Press Room Termite Gut Microbes could Aid Biofuel Production

“Termite Gut Microbiota Contribution to Wheat Straw Delignificaton in Anaerobic Bioreactors”

ACS Sustainable Chemistry & Engineering

Wheat straw, the dried stalks left over from grain production, is a potential source of biofuels and commodity chemicals. But before straw can be converted to useful products by biorefineries, the polymers that make it up must be broken down into their building blocks. Now, researchers reporting in ACS Sustainable Chemistry & Engineering have found that microbes from the guts of certain termite species can help break down lignin, a particularly tough polymer in straw. In straw and other dried plant material, the three main polymers –– cellulose, hemicelluloses and lignin –– are interwoven into a complex 3D structure. The first two polymers are polysaccharides, which can be broken down into sugars and then converted to fuel in bioreactors. Lignin, on the other hand, is an aromatic polymer that can be converted to useful industrial chemicals. Enzymes from fungi can degrade lignin, which is the toughest of the three polymers to break down, but scientists are searching for bacterial enzymes that are easier to produce. In previous research, Guillermina Hernandez-Raquet and colleagues had shown that gut microbes from four termite species could degrade lignin in anaerobic bioreactors. Now, in a collaboration with Yuki Tobimatsu and Mirjam Kabel, they wanted to take a closer look at the process by which microbes from the woodeating insects degrade lignin in wheat straw, and identify the modifications they make to this material. The researchers added 500 guts from each of four higher termite species to separate anaerobic bioreactors and then added wheat straw as the sole carbon source. After 20 days, they compared the composition of the digested straw to that of untreated straw. All of the gut microbiomes degraded lignin (up to 37%), although they were more efficient at breaking down hemicelluloses (51%) and cellulose (41%). Lignin remaining in the straw had undergone chemical and structural changes, such as oxidation of some of its subunits. The researchers hypothesized that the efficient degradation of hemicelluloses by the microbes could have also increased the degradation of lignin that is cross-linked to the polysaccharides. In future work, the team wants to identify the microorganisms, enzymes and lignin degradation pathways responsible for these effects, which could find applications in lignocellulose biorefineries. The authors acknowledge funding from the PHC Sakura program, the Japan Society for the Promotion of Science, the Research Institute for Sustainable Humanosphere, the European Union’s Horizon 2020 ZELCOR program, the French National Research Institute for Agriculture, Food and Environment, the Region Languedoc-Roussillon Midi-Pyrénées grant and the Carnot Institute 3BCAR project.

From the ACS Press Room An mRNA Vaccine for Cancer Immunotherapy

“In Situ Transforming RNA Nanovaccines from Polyethylenimine Functionalized Graphene Oxide Hydrogel for Durable Cancer Immunotherapy” Nano Letters

Messenger RNA (mRNA) vaccines to prevent COVID-19 have made headlines around the world recently, but scientists have also been working on mRNA vaccines to treat or prevent other diseases, including some forms of cancer. Now, researchers reporting in ACS’ Nano Letters have developed a hydrogel that, when injected into mice with melanoma, slowly released RNA nanovaccines that shrank tumors and kept them from metastasizing. Cancer immunotherapy vaccines work similarly to mRNA vaccines for COVID-19, except they activate the immune system to attack tumors instead of a virus. These vaccines contain mRNA that encodes proteins made specifically by tumor cells. When the mRNA enters antigen-presenting cells, they begin making the tumor protein and displaying it on their surfaces, triggering other immune cells to seek and destroy tumors that also make this protein. However, mRNA is an unstable molecule that is quickly degraded by enzymes in the body. For cancer immunotherapy, researchers have tried using nanoparticles to protect and deliver mRNA, but they are typically cleared from the body within 1-2 days after injection. Guangjun Nie, Hai Wang and colleagues wanted to develop a hydrogel that, when injected under the skin, would slowly release mRNA nanoparticles, along with an adjuvant –– a molecule that helps activate the immune system. To develop their system, the researchers used ovalbumin (a protein found in chicken egg whites) as a model antigen. The team mixed ovalbumin mRNA and an adjuvant with other compounds to form a hydrogel. When injected under the skin of mice with melanoma tumors engineered to express ovalbumin, the hydrogel slowly released mRNA and adjuvant nanoparticles over a 30 -day period. The mRNA vaccine activated T cells and stimulated antibody production, causing tumors to shrink in the treated mice. Also, in contrast to untreated mice, the vaccinated mice did not show any metastasis to the lung. These results demonstrate that the hydrogel has great potential for achieving long-lasting and efficient cancer immunotherapy with only a single treatment, the researchers say. The authors acknowledge funding from the National Key R&D Program of China, the National Natural Science Foundation of China, the Chinese Academy of Sciences and the K. C. Wong Education Foundation.

From the ACS Press Room

Ghosts of Past Pesticide use can Haunt Organic Farms for Decades

“Widespread Occurrence of Pesticides in Organically Managed Agricultural Soils— the Ghost of a Conventional Agricultural Past?” Environmental Science & Technology

Although the use of pesticides in agriculture is increasing, some farms have transitioned to organic practices and avoid applying them. But it’s uncertain whether chemicals applied to land decades ago can continue to influence the soil’s health after switching to organic management. Now, researchers reporting in ACS’ Environmental Science & Technology have identified pesticide residues at 100 Swiss farms, including all the organic fields studied, with beneficial soil microbes’ abundance negatively impacted by their occurrence.

Fungicides, herbicides and insecticides protect crops by repelling or destroying organisms that harm the plants. In contrast, organic agriculture management strategies avoid adding synthetic substances, instead relying on a presumably healthy existing soil ecosystem. However, some organic farms are operating on land treated with pesticides in the past. Yet, it’s unclear whether pesticides have a long-lasting presence in organically managed fields and what the reverberations are to soil life, specifically microbes and beneficial soil fungi, years after their application. So, Judith Riedo, Thomas Bucheli, Florian Walder, Marcel van der Heijden and colleagues wanted to examine pesticide levels and their impact on soil health on farms managed with conventional versus organic practices, as well as on farms converted to organic methods. The researchers measured surface soil characteristics and the concentrations of 46 regularly used pesticides and their breakdown products in samples taken from 100 fields that were managed with either conventional or organic practices. Surprisingly, the researchers found pesticide residues at all of the sites, including organic farms converted more than 20 years prior. Multiple herbicides and one fungicide remained in the surface soil after the conversion to organic practices; though the total number of synthetic chemicals and their concentrations decreased significantly the longer the fields were in organic management. According to the researchers, some of the pesticides alternatively could have contaminated the organic fields by traveling through the air, water or soil from nearby conventional fields. In

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The Doherty Award is given for excellence in chemical research or chemistry teaching, Nominees may come from industry, academia, government, or small business. The nominee should be a resident member in the area served by the ACS DFW Local Section, and the work should have been performed here. The award is $1500 and an engraved plaque. The Schulz Award is given to high school chemistry teachers, who, like the late Dr. Werner Schulz, bring that something extra to the teaching of chemistry. The nominee and/ or nominator need not be ACS members. Nominees should show excellence in chemistry teaching, as demonstrated by testimonials from students and fellow teachers, results in student competitions, and diligence in updating and expanding scientific/teaching credentials. The award is $1500 and an engraved plaque.

The DFW Section instituted the Chemistry

Ambassador Award to recognize an outstanding Section member who has made a significant impact by promoting chemistry to the community. The 2021 Chemistry Ambassador of the Year award is based on peer or self-nominations to the selection committee. Submissions should be one page in length and address the community outreach activities either through teaching, service, or working with legislators to affect public policy. Submissions will be evaluated on the impact made, which may include but not limited to how many people were reached, impact on individual people in the community, and exemplary commitment to

the promotion of chemistry in the community. The award is $500. Each nomination should contain a completed nomination form, a cover letter highlighting the nominee’s accomplishments, and a copy of the CV. One second letter may accompany nominations. The nomination package should be sent by email as a single pdf file to Dr. Trish Smith at trishsmithtx@gmail.com. Nominations remain active for five years but should be updated annually.

The deadline is May 01, 2021

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addition, the team observed lower microbial abundance and decreased levels of a beneficial microbe when fields had higher numbers of pesticides in the fields, suggesting that the presence of these substances can decrease soil health. The researchers say future work smeritorious service to ACS, new chemical methodology (for the industry), solution of pollution problems, and advances in curative or preventive chemotherapy. hould examine the synergistic effects of pesticide residues and other environmental stressors on soil health. The authors acknowledge funding from Agroscope, Swiss Federal Office for the Environment, the Swiss National Science Foundation and the National Research Program ‘Sustainable use of soil as a resource’ .