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Development,
2021]
Swathi Arur is an Associate Professor for the Department of Genetics at the MD Anderson Cancer Center, USA, where she uses multidisciplinary approaches to understand female germline development and fertility. She has received numerous accolades, including the MD Anderson Distinguished Research Faculty Mentor Award in 2017. In 2020, she was elected to the American Association for the Advancement of Science (AAAS). Swathi joined the team at Development as an Academic Editor in 2020, and we met with her over Zoom to hear more about her life, her career and her love for <i>C. elegans</i>.
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Cell Host Microbe,
2017]
Microbes affect drug responses, but mechanisms remain elusive. Two papers in Cell exploit C.elegans to infer anticancer drug mechanisms. Through high-throughput screens of drug-microbe-host interactions, Garcia-Gonzalez etal. (2017) and Scott etal. (2017) determine that bacterial metabolism underpins fluoropyrimidine cytotoxicity, providing a paradigm for unraveling bacterial mechanisms in drug metabolism.
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Dev Cell,
2019]
In this issue of Developmental Cell, Anderson etal. (2019) show that chromatin domain structure on the X chromosome in C.elegans is dispensable for dosage compensation but regulates longevity and thermotolerance. This study sheds light on the mechanisms of domain formation in C.elegans and how these features affect physiology.
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Traffic,
2017]
Steady axonal cargo flow is central to the functioning of healthy neurons. However, a substantial fraction of cargo in axons remains stationary up to several minutes (Kang, Tian et al. 2008, Tang, Scott et al. 2012, Tang, Scott et al. 2013, Iacobucci, Rahman et al. 2014). We examine the transport of precursors of synaptic vesicles (pre-SVs), endosomes and mitochondria in C. elegans touch receptor neurons (TRNs), showing that stationary cargo are predominantly present at actin-rich regions along the neuronal process. Stationary vesicles at actin-rich regions increase the propensity of moving vesicles to stall at the same location, resulting in traffic jams arising from physical crowding. Such local traffic jams at actin-rich regions are likely to be a general feature of axonal transport since they also occur in Drosophila neurons. Repeated touch stimulation of C. elegans reduces the density of stationary pre-SVs, indicating that these traffic jams can act as both sources and sinks of vesicles. This suggests that vesicles trapped in actin-rich regions are functional reservoirs that may contribute to maintaining robust cargo flow in the neuron.
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Mol Cell Biol,
2010]
Prolonged cellular hypoxia results in energy failure and ultimately cell death. However, less-severe hypoxia can induce a cytoprotective response termed hypoxic preconditioning (HP). The unfolded protein response pathway (UPR) has been known for some time to respond to hypoxia and regulate hypoxic sensitivity; however, the role of the UPR, if any, in HP essentially has been unexplored. We have shown previously that a sublethal hypoxic exposure of the nematode Caenorhabditis elegans induces a protein chaperone component of the UPR (L. L. Anderson, X. Mao, B. A. Scott, and C. M. Crowder, Science 323:630-633, 2009). Here, we show that HP induces the UPR and that the pharmacological induction of misfolded proteins is itself sufficient to stimulate a delayed protective response to hypoxic injury that requires the UPR pathway proteins IRE-1, XBP-1, and ATF-6. HP also required IRE-1 but not XBP-1 or ATF-6; instead, GCN-2, which is known to suppress translation and induce an adaptive transcriptional response under conditions of UPR activation or amino acid deprivation, was required for HP. The phosphorylation of the translation factor eIF2, an established mechanism of GCN-2-mediated translational suppression, was not necessary for HP. These data suggest a model where hypoxia-induced misfolded proteins trigger the activation of IRE-1, which along with GCN-2 controls an adaptive response that is essential to HP.
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MicroPubl Biol,
2022]
Caenorhabditis elegans is a model species, increasingly used in experimental evolution studies to investigate such major topics as: maintenance of genetic variation, host-pathogen interaction and coevolution, mutations, life history, evolution of reproductive systems, sexual selection (Gray and Cutter, 2014; Teotnio, Estes, Phillips, and Baer, 2017). Its reproductive system in the wild, known as androdioecy, involves mostly self-fertilization of hermaphrodites and occasionally outcrossing with males, which are generally rare (Stewart and Phillips, 2002). This system can be experimentally changed to dioecy, i.e., obligatory outcrossing, through genetic manipulations (see Table I in Anderson, Morran, and Phillips, 2010; Gray and Cutter, 2014).
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Int J Food Microbiol,
2008]
Listeria monocytogenes is an important foodborne bacterial pathogen that can colonize food processing equipment. One group of genetically similar L. monocytogenes strains (RAPD type 9) was recently shown to reside in several independent fish processing plants. Persistent strains are likely to contaminate food products, and it is important to determine their virulence potential to evaluate risk to consumers. We compared the behaviour of food processing persistent and clinical L. monocytogenes strains in four virulence models: Adhesion, invasion and intracellular growth was studied in an epithelial cell line, Caco-2; time to death in a nematode model, Caenorhabditis elegans and in a fruit fly model, Drosophila melanogaster and fecal shedding in a guinea pig model. All strains adhered to and grew in Caco-2 cells in similar levels. When exposed to 10(6) CFU/ml, two strains representing the persistent RAPD type 9 invaded Caco-2 cells in lower numbers (10(2)-10(3) CFU/ml) as compared to the four other strains (10(4)-10(6) CFU/ml), including food and human clinical strains. In the D. melanogaster model, the two RAPD type 9 strains were among the slowest to kill. Similarly, the time to reach 50% killed C. elegans worms was longer (110 h) for the RAPD type 9 strains than for the other four strains (80 h). The Scott A strain and one RAPD type 9 strain were suspended in whipping cream before being fed to guinea pigs and the persistent RAPD type 9 strain was isolated from feces in a lower level (approximately 10(2) CFU/g) than the Scott A strain (approximately 10(5) CFU/g) (P<0.05). The addition of NaCl has been shown to cause autoaggregation and increases adhesion of L. monocytogenes to plastic. However, growth in the presence of NaCl did not alter the behaviour of the tested L. monocytogenes strains in the virulence models. Overall, the two strains representing a very common fish processing plant persistent group (RAPD type 9) appear to have a lower virulence potential in all four virulence models than Scott A and a strain isolated from a clinical case of listeriosis.
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Nematologica,
1969]
Several investigators have reported that nutritional or environmental factors induce morphological variations in the "so-called' bacteriophagous nematodes. For example, Nigon & Dougherty described a morphological mutant of the free-living, self-fertilizing, hermaphroditic nematode Rhabditis (Caenorhabditis) briggsae that ensued following heat-treatment of progeny cultured on bacteria. Also Anderson reported that certain diagnostic features of an Acrobeloides sp., specifically the shape of the labial probolae and tail, varied significantly when the nematodes were grown on bacterial cultures as compared to those grown in soil. The current paper describes a consistent morphological variation in Caenorhabditis briggsae grown axenically on a meridic medium containing a growth factor from a bacterium as compared with nematodes reared on a growth factor from liver extract.
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Fundamental and Applied Nematology,
1997]
The effects of structural heterogeneity on both chemical diffusion and nematode movement are examined with the development of a theoretical model. The model considers three factors affecting nematode movement: soil structure, nematode foraging strategy and chemotaxis. Using a continuous model, we develop a discrete system which allows nematode trails to be simulated in any of the four experimental conditions given by Anderson et al (1997). We show that structural heterogeneity causes mixed levels of attractant concentration over small areas as well as "fingering" of the attractant. Soil structural heterogeneity also restricts the foraging strategy of the nematode which then becomes a strategy to avoid structural "traps". The effect of localised increases in structural density is shown to increase significantly "fingering" of the attractant.
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Biosci Biotechnol Biochem,
2014]
We demonstrate the inhibitory effects of -casein macropeptide (CMP) on the biofilm formation and virulence of Listeria monocytogenes Scott A. The inhibition of biofilm formation by CMP was initially investigated by using the protocol applied for the 96-well microtiter plate assay. Low concentrations of CMP (0.1, 0.2, 0.3, 0.4, and 0.5 mg/mL) that were tested resulted in a profound inhibitory effect on biofilm formation at a concentration of 0.4 mg/mL. CMP also significantly repressed the transcription of inlA (encoding internalin A) that was responsible for the initial adhesion and invasion event, and prolonged the survival of Caenorhabditis elegans infected by L. monocytogenes. Two-dimensional gel electrophoresis showed that newly identified proteins in the presence of CMP were involved in the stress response and metabolic processes that have important roles in developing listerial biofilms. Our results suggest that CMP from milk protein would be capable of eliminating biofilm formation and virulence by L. monocytogenes in the food industry.