Oxidative Stress in Caenorhabditis elegans: Protective Effects of Spartin

Troyer syndrome is caused by a mutation in the SPG20 gene, which results in complete loss of expression of the protein spartin. We generated a genetic model of Troyer syndrome in worms to explore the locomotor consequences of a null mutation of the Caenorhabditis elegans SPG20 orthologue, F57B10.9, also known as spg-20. Spg-20 mutants showed decreased length, crawling speed, and thrashing frequency, and had a shorter lifespan than wild-type animals. These results suggest an age-dependent decline in motor function in mutant animals. The drug paraquat was used to induce oxidative stress for 4 days in the animals. We measured survival rate and examined locomotion by measuring crawling speed and thrashing frequency. After 4 days of paraquat exposure, 77% of wild-type animals survived, but only 38% of spg-20 mutant animals survived. Conversely, animals overexpressing spg-20 had a survival rate of 95%. We also tested lifespan after a 1 hour exposure to sodium azide. After a 24 hour recovery period, 87% of wild type animals survived, 57% of spg-20 mutant animals survived, and 82% of animals overexpressing spg-20 survived. In the behavioral assays, spg-20 mutant animals showed a significant decrease in both crawling speed and thrashing frequency compared with wild-type animals. Importantly, the locomotor phenotype for both crawling and thrashing was rescued in animals overexpressing spg-20. The animals overexpressing spg-20 had crawling speeds and thrashing frequencies similar to those of wild-type animals. These data suggest that the protein F57B10.9/SPG-20 might have a protective role against oxidative stress.     

Class 1 Integrons and Antibiotic Resistance of Clinical Acinetobacter calcoaceticus–baumannii Complex in Poznań, Poland

Sixty-three clinical isolates of Acinetobacter calcoaceticus–baumannii complex were analyzed for the presence of integrons and antimicrobial resistance. Class 1 integrons were detected in 40 (63.5 %) isolates. None of them had class 2 or class 3 integrons. The majority of the integrons contained aacC1–orfA–orfB–aadA1 gene cassette array. The presence of integrons was associated with the increased frequency of resistance to 12 of 15 antimicrobials tested, multi-drug resistance phenotype, and the overall resistance ranges of the strains.     

Effect of medicating ingredients and other additives on microflora present on swine and chicken feeds from a Manitoba mill

The occurrence of microfloral components on medicated and non-medicated swine and chicken feed pellets and crumbles, produced in a Manitoba feed mill between June 1991 and October 1992, was determined. Addition of medicates to feeds generally decreased bacterial incidence and increased that of Eurotium spp. fungi. The effect was less pronounced when copper sulphate was added to medicated swine feeds.Contribution No. 1662.     

IL-2 secretion is pertussis toxin sensitive in a T lymphocyte hybridoma

Interaction of specific ligands with TCR initiates a cascade of biochemical events which leads to expression of high affinity IL-2R and subsequent IL-2 secretion. Activation of phospholipase C (PL-C) is considered to be a key event in the initiation of this cascade. However, in addition to this PL-C-dependent pathway, PL-C-independent pathways have been hypothesized. Identification of the steps constituting these PL-C-independent pathways has been difficult because activation of PL-C and the subsequent cascade of events mask the effects of such pathways. Specific inhibitors for PL-C, or mutants defective in, the PL-C pathway would facilitate delineation of alternative activation pathways. We have identified a murine pork insulin/IAd-specific T cell hybridoma, B8P3.11, in which perturbation of the B8P3.11 TCR by either Ag in association with Ia, anti-CD3 antibodies, or a mitogenic lectin does not induce increases in myo-inositol 1,4,5-triphosphate production or cytosolic free calcium, yet it does lead to IL-2 secretion. Treatment of B8P3.11 with pertussis toxin, at concentrations which ADP-ribosylate GTP-binding proteins, inhibits IL-2 secretion. Thus, signal transduction resulting in IL-2 secretion by B8P3.11 likely involves a G protein. In contrast, TCR/ligand interaction activates the PL-C-dependent pathway in LBRM 331A5, a T cell lymphoma. Furthermore, pertussis toxin treatment, which blocks IL-2 secretion by B8P3.11, does not alter IL-2 secretion by LBRM 331A5. However, similar pertussis toxin substrates are present in both cells. Therefore, B8P3.11 T cells should help to elucidate PL-C-independent activation pathways.     

BET inhibition blocks inflammation-induced cardiac dysfunction and SARS-CoV-2 infection

1. Download : Download high-res image (195KB)
2. Download : Download full-size image

     

Lipid changes during development of Blastocladiella emersonii

The lipid composition of swimming spores, cysts and five hour germlings was established. Spores utilized triglycerides first, then phospholipids. Upon encystment all glycolipid components decreased, while in germlings the phospholipids, monoglycerides and sterol esters exhibited a marked increase.