Dynamin is a large GTPase responsible for diverse cellular processes, such as endocytosis, division of organelles, and cytokinesis. The social amoebozoan, Dictyostelium discoideum, has five dynamin-like proteins: dymA, dymB, dlpA, dlpB, and dlpC. DymA, dlpA, or dlpB-deficient cells exhibited defects in cytokinesis. DlpA and dlpB were found to colocalize at cleavage furrows from the early phase, and dymA localized at the intercellular bridge connecting the two daughter cells, indicating that these dynamins contribute to cytokinesis at distinct dividing stages. Total internal reflection fluorescence microscopy revealed that dlpA and dlpB colocalized at individual dots at the furrow cortex. However, dlpA and dlpB did not colocalize with clathrin, suggesting that they are not involved in clathrin-mediated endocytosis. The fact that dlpA did not localize at the furrow in dlpB null cells and vice versa, as well as other several lines of evidence, suggests that hetero-oligomerization of dlpA and dlpB is required for them to bind to the furrow. The hetero-oligomers directly or indirectly associate with actin filaments, stabilizing them in the contractile rings. Interestingly, dlpA, but not dlpB, accumulated at the phagocytic cups independently of dlpB. Our results suggest that the hetero-oligomers of dlpA and dlpB contribute to cytokinesis cooperatively with dymA.

Furazolidone, a banned nitrofuran antibiotic, is still illegally used in aquaculture and livestock husbandry. A commercial Enzyme-linked Immunosorbent Assay (ELISA) from Europroxima, The Netherlands is described, and validated for the screening of 3-amino-2-oxazolidinone (AOZ), metabolite of furazolidone antibiotic in the muscle of shrimp. Research works was conducted at Veterinary Drug Residue Analysis Laboratory, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka-1349, between July 2018 and December 2019. Validation was done in accordance with the European Commission (EC) decision 2002/657/EC in terms of specificity, detection capability CCβ, selectivity, ruggedness, and stability. Homogenized sample was subjected to acid hydrolysis for releasing of tissue bound metabolite AOZ, and derivatized with o-nitrobenzaldehyde followed by ethyl acetate/n-hexane extraction and detection by ELISA reader. The detection capability CCβ of the method was lower or at 0.3 µg/kg accepting 0% false compliant result. Cut-off factor Fm and the positivity threshold value T was 0.716 and 0.982, respectively. Mean OD of blank sample B was1.225. The assay was valid because T was greater than Fm and smaller than B. The kit was stable even after ten months of storage at recommended temperature and showed good sensitivity. From the practical point of view, the kit studied has good reliability, and could be used in the routine application for the control of illegal use of the drug.