BioTech

Carotenoid-based pigmentation is crucial for the ornamental and commercial value of the cherry shrimp (Neocaridina denticulata sinensis). While several genes are known to influence carotenoid metabolism, the genetic basis for specific color strains remains largely unexplored. Here, we functionally characterized NinaB-like, a homolog of a carotenoid oxygenase, in cherry shrimp pigmentation. We employed qPCR to gain gene expression profiles, utilized RNAi technology to analysize the relation between its expression level and carotenoid accumulation, and performed GT-seq to identify genotypes of different color strains. Significant differential expression of NinaB-like was observed not only across distinct color strains but also during embryonic development of cherry shrimp (p < 0.05), peaking at the red strain and post-larval stage of cherry shrimp. RNA interference-mediated knockdown of NinaB-like resulted in a marked increase in red pigment deposition at the metanauplius and pre-zoea stages, confirming its role as a negative regulator of carotenoid accumulation. Importantly, we identified two tightly linked, non-synonymous SNPs (927C > A and 935A > C) within the NinaB-like coding region that exhibited a strong association with body color. Our study provides the first functional evidence that NinaB-like is a negative regulator of carotenoid degradation and a major genetic determinant for body color in cherry shrimp, providing new insights for genetic breeding and biological research.

Human embryonic kidney (HEK293) cells are a widespread choice for recombinant protein expression. To optimise yields, the hydrolysate Tryptone N1 (TN1) is commonly added post-transfection. TN1 is obtained by controlled enzymatic digestion of casein. As an animal by-product, TN1 faces stricter regulations during cross-country shipments than plant-based products. This raises the question of whether plant-derived peptides are a suitable alternative to TN1. Using polyethyleneimine (PEI) as a cationic polymer, we transfected HEK293-6E cells grown in suspension in serum-free medium and divided the transfectants into four groups (each in triplicate). Two plant-based hydrolysates each derived from pea and broad bean were compared with TN1 and a no-hydrolysate control group. We monitored the cultures for total cell numbers and viability at days 1, 4, and 5 post-transfection. Both plant-based hydrolysates and TN1 showed similar live cell percentages, in contrast to the no-hydrolysate control, which showed lower viability. Five days post-transfection, the expressed His-tagged protein, a tegumental antigen from the eukaryotic parasite Echinococcus granulosus, was retrieved from the serum-free culture supernatant, and the expressed recombinant protein was quantified. The linear ranges for the protein load on the stain-free blot and for the use of the fluorescent anti-His-Tag Alexa₄₈₈ antibody were determined. Using these parameters, stain-free Western blotting and total protein normalization were performed. The plant-derived pea and broad bean hydrolysates reproducibly resulted in similar expression levels as animal-derived TN1; all three hydrolysates were better than no hydrolysate. We conclude that plant-derived hydrolysates are a suitable, more sustainable replacement for TN1.

This study investigates the functional role of OsHSBP1, a heat shock factor-binding protein, in regulating abiotic stress tolerance in rice, with the aim of enhancing climate resilience in the elite indica cultivar Bacthom 7 (BT7). Using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/Cas9) genome editing, we generated transgene-free homozygous knockout lines targeting OsHSBP1 and evaluated their physiological, biochemical, and agronomic responses under heat stress. Mutant lines exhibited markedly improved tolerance to both stresses, with survival rates reaching 43–46% under heat stress, compared to near-zero in wildtype plants. Enhanced tolerance was associated with significantly increased catalase and peroxidase activities and reduced oxidative damage, including lower malondialdehyde content and decreased superoxide accumulation. Despite these stress-related advantages, the knockout lines showed minimal differences in key agronomic traits under normal growing conditions, with comparable plant height, tillering ability, grain yield, and amylose content relative to the wildtype. These results demonstrate that OsHSBP1 functions as a negative regulator of abiotic stress tolerance in rice, and its knockout enhances resilience without compromising yield potential. The study highlights OsHSBP1 as a promising target for precision breeding of climate-resilient rice cultivars.