- Author: Kathy Keatley Garvey
Meet Chryseobacterium kimseyorum, named for UC Davis distinguished professor Lynn Kimsey, director of the Bohart Museum, and her husband, forensic entomologist Robert "Bob" Kimsey, both of the Department of Entomology and Nematology.
“We've had a few things named after us but never bacteria--that's a first,” said Lynn Kimsey.
The story begins more than a decade ago when then UC Davis doctoral student Matan Shelomi, now an associate professor of entomology at National Taiwan University, Taiwan, was studying the digestive physiology of the stick and leaf insects, Phasmatodea, for his Ph.D, under the guidance of his major professor, Lynn Kimsey. He isolated and cultured bacteria from the guts and cages of the stick insects. Some of the species seemed new to science, but Shelomi had neither the time nor the resources to prove it then.
He stored the microbes inside the deep freezers of the Phaff Yeast Culture Collection, UC Davis Department of Food Science and Technology.
The years slipped by. So did the memory of isolating the bacteria. Then after becoming a professor himself, his graduate student, Chiao-Jung Han, discovered a new bacteria species inside a beetle. That prompted Shelomi to renew his interest in the microbes from the Bohart Museum.
"Thankfully, I kept all my notes from graduate school," says Shelomi, "so I was able to check and see which strains I had flagged as possibly new species. When I saw one of them was the same genus as the new microbe found in Taiwan, I realized this was an opportunity to describe them both together." So Shelomi emailed Kyria Boundy-Mills, curator of the Phaff Collection, “who had my old specimen revived and shipped across the Pacific.”
The abstract begins: “Two strains of Chryseobacterium identified from different experiments are proposed to represent new species. Strain WLa1L2M3T was isolated from the digestive tract of an Oryctes rhinoceros beetle larva. Strain 09-1422T was isolated from a cage housing the stick insect Eurycantha calcarata. Sequence analysis of the 16S rRNA and rpoB genes found both strains to be similar but not identical to other Chryseobacterium species. Whole-genome sequencing suggested the isolates represent new species, with average nucleotide identity values ranging from 74.6 to 80.5?%.”
Tabatha Yang, education and outreach coordinator of the Bohart Museum, relayed the news to a tour group visiting the insect museum on April 20. “I just used this story today with a tour group,” she told Shelomi. “I mentioned how your student was denied her dog's name. I love how this ties the Bohart and the Phaff Yeast collection together and then California and Taiwan.”
As for the stick insect, “It's pretty aggressive for a walking stick,” Lynn Kimsey said, noting that Andy Engilis, curator of the UC Davis Museum of Wildlife and Fish Biology, told her about his work in Papua New Guinea. “These walking sticks would actually chase rodents out of their burrows and take over the burrows to rest in,” she related. “That's pretty tough for a walking stick.”
Meanwhile, the Kimseys are enjoying their new namesake. Lynn Kimsey already has seven other species named for her:
- Mystacagenia kimseyae Cambra & Wasbauer 2020 (spider wasp)
- Oligoaster kimseyae Soliman 2013 (tiphiid wasp)
- Exaerate kimseyae Oliviera 2011 (orchid bee)
- Spilomena kimseyae Antropov 1993 (solitary wasp)
- Manaos kimseyae Smith (argid sawfly)
- Spintharina kimseyae Bohart 1987 (cuckoo wasp)
- Neodryinus kimseyae Olmi 1987 (dryinid wasp)
Bob Kimsey has as at least two species named for him: Acordulacera kimseyi Smith, 2010 (sawfly) and Grandiella kimseyi Summers & Schuster (mite).
Shelomi, a Harvard University graduate who received his doctorate from UC Davis in 2014, served as a National Science Foundation postdoctoral fellow at the Max Planck Institute for Chemical Ecology, Germany for two years before accepting a faculty position in 2017 at National Taiwan University.
Shelomi returned to UC Davis in 2017 to present a seminar on "Revelations from Phasmatodea Digestive Track Transcriptomics,” to the department.
- Author: Emily C. Dooley, UC Davis
E. coli and Salmonella are rare in wild birds, Campylobacter more common
Concerns over foodborne risk from birds may not be as severe as once thought by produce farmers, according to research from the University of California, Davis, that found low instances of E. coli and Salmonella prevalence.
While the research found that the risk is often low, it varies depending on species. Birds like starlings that flock in large numbers and forage on the ground near cattle are more likely to spread pathogenic bacteria to crops like lettuce, spinach and broccoli, according to a study of food safety risk and bird pathogens from the University of California Davis. In contrast, insect-eating species were less likely to carry pathogens.
The findings, published in the journal Ecological Applications, suggest that current practice of removing bird habitats around produce growers' farms over concerns the animals could bring foodborne pathogens into their fields may not solve the problem.
“Farmers are increasingly concerned that birds may be spreading foodborne diseases to their crops,” said Daniel Karp, the senior author on the study and an assistant professor in the UC Davis Department of Wildlife, Fish and Conservation Biology. “Yet not all bird species are equally risky.”
Only one foodborne disease outbreak in produce has been conclusively traced to birds: a Campylobacter outbreak in peas from Alaska. While the bacteria can cause diarrhea and other foodborne illness in humans, it's less of a concern to growers than E. coli and Salmonella, which have been responsible for multiple outbreaks across the nation.
In this study, researchers compiled more than 11,000 bacteria tests of wild bird feces and found that Campylobacter was detected in 8 percent of samples. But pathogenic E. Coli and Salmonella were only found in very rare cases (less than 0.5%).
In addition to the bacteria tests, researchers conducted roughly 1,500 bird surveys across 350 fresh produce fields in Western states and collected more than 1,200 fecal samples from fields. They then modeled the prevalence of pathogens in feces, interactions with crops, and the likelihood of different bird species to defecate on crops to determine risk.
Insect-eating birds pose lower risk
Based on the data, insect-eating birds, such as swallows, present a lower risk, while birds that flock near livestock, such as blackbirds and starlings, are more likely to transmit pathogens.
The data can help the agricultural industry determine risk and take action, such as separating produce crops from cattle lands. They also don't need to treat all birds the same.
“Maybe farmers don't need to be quite as concerned about all types of birds,” Karp said. “Our data suggest that some of the pest-eating birds that can really benefit crop production may not be so risky from a food-safety perspective.”
Removing habitat can backfire
This study and the authors' prior work indicate that removing habitat around farms may actually benefit the species that pose more risk and harm the beneficial, pest-eating ones that are less risky to food safety. This is because many prolific insect-eaters may visit crop fields to eat pests but need nearby natural habitats to survive. In contrast, many of the bird species that most commonly carry foodborne pathogens readily thrive on both cattle farms and produce farms without natural habitat nearby.
Other findings
Insect-eating birds that forage in the tree canopy pose minimal threat because they are less likely to carry foodborne pathogens and come into direct contact with produce. They can also be valuable parts of the ecosystem, particularly if they eat pests that can harm crops. Installing bird boxes could attract the pest-eaters, as well as help with conservation efforts.
“We basically didn't know which birds were problematic,” said lead author Olivia Smith, a postdoctoral researcher at Michigan State University who was at University of Georgia when the paper was written. “I think this is a good step forward for the field.”
Additional co-authoring institutions include James Cook University, UC Berkeley, UC Riverside, University of Kentucky, University of Texas, Virginia Polytechnic Institute and State University, Washington State University, BioEpAr, The Nature Conservancy and Van Andel Institute.
The research was funded by the United States Department of Agriculture and the National Science Foundation.
/h3>/h3>/h3>/h2>- Author: Belinda J. Messenger-Sikes
- Author: Karey Windbiel-Rojas
Like outdoor plants, houseplants can also experience pest problems. Did you know that too much or too little watering is the most common way that houseplants die? They can also suffer from too much or too little light, incorrect fertilization, and a variety of pests and diseases. Knowing the proper growing conditions for your houseplant and checking regularly for signs of pests or disease are the best ways to keep your houseplants healthy.
If your houseplant is looking unhealthy, our newest publication Pest Notes: Houseplant Problems can help you find out what may be wrong. Authored by UCCE Environmental Horticulturalists Dennis Pittenger and Donald Hodel, this new resource can help you narrow down the cause of a plant problem and decide what actions to take. If you find . You'll find sections on many common pests like aphids, mites, and mealybugs as well as leaf spots, wilting, or other disease symptoms. Once you've figured out the problem, you will also be able to find out how to manage to manage it use less toxic methods.
If you have feedback on this or other Pest Notes publications, let us know what you think by filling out this quick, anonymous survey.
- Author: Elizabeth E Grafton-Cardwell
- Author: Peggy G. Lemaux
- Author: Barbara Alonso
This project focuses on developing an automated method for delivering therapeutic liquid materials directly into the citrus phloem. The delivery method is called Needle-Assisted Trunk Infusion (NATI) and uses an ATV with a robotic arm to deliver the therapeutics.
How exactly is it done, and what are the challenges and opportunities with this new way to treat the disease? Visit the Research Snapshot to learn more: https://ucanr.edu/sites/scienceforcitrushealth/Research_Snapshots/Batuman
We have developed short descriptions of research projects that aim to help in the fight against HLB. These projects include traditional breeding and genetic engineering to create resistant citrus varieties, modifying psyllids, employing other organisms to deliver HLB-resistance and using early detection methods to identify the bacterium in trees.
- Author: Ben Faber
Under our feet, in the soil, is a wealth of microbial activity. Just like humans have different metabolisms and food choices, so do those microbes. In fact, microbes play an important role in making nutrients available to plants.
A recent review paper from Xinda Lu and his team looks at different roles that various soil microbes have in soil's nitrogen cycle. Lu is a researcher at Massachusetts Institute of Technology.
According to Lu, "Soil microbes catalyze most of the transformations of soil nitrogen into plant-usable forms. Diverse microbes use different processes - and sometimes work together. Knowing the various styles of soil microbes, and linking microbes to specific soil processes, can be important knowledge for farmers."
Modern nitrogen fertilizers are applied in the form of ammonium. Through a biological process called nitrification, soil microbes convert ammonium to nitrates that plants can absorb. In order to be efficient at this process, microbes need oxygen. Researchers are studying nitrification because it can be linked to greenhouse gases and loss of fertilizer.
Although microbiologists have been studying the nitrogen cycle for over a century, not all steps were well understood. New microorganisms have recently been identified. A type of prokaryote (single-celled organism) called archaea has also been playing a role in nitrification.
Archaea are not technically soil bacteria, due to their structure. These are newly a newly classified group that really do some amazing things. There are many more archaea that contribute to nitrification in some soils than there are bacteria responsible for the same activity. Including the role of archaea in nitrification has broadened the understanding of scientists and researchers.
Researchers reviewed various studies of soil nitrification. This included the abundance of microbes in soil in relation to various environmental factors. Soil pH, temperature and the ratio of soil carbon to soil nitrogen were all compared to the number of microbes in each soil sample. Soil depth and other factors also influence microbe abundance.
Previous studies have shown, for example, that nitrification archaea are more abundant than bacteria in warmer temperatures. Other microbes thrive in lower temperatures.
Soil pH also influences how active soil microbes are in the nitrification process. Soil bacteria Nitrospira were more dominant in acidic soils, including forests and farm fields.
Researchers have also studied how various microbes "talk" to each other. This keeps the nitrification process running smoothly. Various mechanisms have been proposed, including cell signaling. The presence of nitric oxide in soils may enhance interactions between microbes.
Soil scientists are sure they have not found all the microbes that contribute to the vast array of services soils provide. Just as astronomers discover new stars in the sky as tools advance, so will soil microbiologists find new soil microbes. Some may be involved in nitrification.
Collecting and cataloging the type, abundance and location of soil microbes will continue to advance the knowledge we have about the soil nitrogen cycle.
Crenarchaeota are involved with nitrification in the soil. Here's a cell of this group infected by virus STSV1 observed under microscopy.