Khanom, M. G. | Search bioRxiv

bioRxiv2025

Oocyte surface proteins EGG-1 and EGG-2 are required for eggshell integrity in Caenorhabditis elegans

Metazoan eggs are surrounded by a specialized coat of extracellular matrix that mediates sperm-egg interactions. This coat is rapidly remodeled after fertilization to form a barrier that prevents polyspermy, protects against environmental insults, and provides structural support to the developing embryo. In C. elegans several oocyte surface proteins have been identified that mediate these events. However, whether two of these proteins, EGG-1 and EGG-2, are required for fertilization or downstream events has been unclear. Here, we address this question using more recent advances in genome editing tools through the creation of egg-1 egg-2 deletions of the endogenous loci. We found that egg-1 egg-2 oocytes are fertilization competent and form rudimentary eggshells. While the integrity of the egg-1 egg-2 eggshells are compromised and often rupture within the uterus, surprisingly, some embryos are capable of undergoing several rounds of cell division. Overall, our findings demonstrate that EGG-1 and EGG-2 are not required for fertilization but are involved in post-fertilization processes.

developmental biology↗

bioRxiv2021

Partial characterization and the evaluation of antimicrobial activities of silver nanoparticles biosynthesized from Cymbopogon citratus leaf extract

BackgroundSilver nanoparticles (AgNPs) are toxic to microorganisms and can potentially kill multidrug-resistant bacteria. Nanoparticles can be synthesized in many different ways, such as physical or chemical methods. Recently, it has been found that plant molecules can perform the same reduction reactions necessary for the production of nanoparticles but in a much more efficient way. ResultsHere, green chemistry was employed to synthesize silver nanoparticles using leaf extracts of Cymbopogon citratus. Effects of different parameters such as temperature, pH and volume of plant extract were also tested using their absorbance pattern at different wavelengths. The Surface Plasmon Resonance (SPR) changed with the changes in parameters. Changes in temperature from 20{degrees}C to 60{degrees}C have changed the highest absorbance from 0.972 to 3.893 with an SPR of 470 nm. At higher pH (11.1), the particles become highly unstable and have irregular shapes and sizes. At lower pH (3.97), the peak shifts to the right, indicating a smaller but unstable compound. We have also investigated the effect of the volume of plant extracts on the reaction time. The sample with the highest amount of plant extract showed the most absorbance with a value of 0.963 at {lambda}max, which was calculated to be 470 nm. The total formation of the AgNPs was observed visually with a color change from yellow to brownish-black. UV-visible spectroscopy was used to monitor the quantitative formation of silver nanoparticles, showing a signature peak in absorbance between 400 and 500 nm. We have estimated the size of the nanoparticles as 47nm by comparing the experimental data with the theoretical value using Mieplot. The biosynthesized silver nanoparticles showed enhanced antibacterial activity against several multidrug-resistant bacteria, determined based on the minimal inhibitory concentration and zone of inhibition. ConclusionThe findings of this study indicate that an aqueous extract of C. citratus can synthesize silver nanoparticles when silver nitrate is used as a precursor and silver nanoparticles act as antimicrobial properties enhancers. These findings can influence further studies in this field to better understand the properties and applications of nanoparticles.

molecular biology↗