Biology subjects

Nejat, N.

Publications and source records attributed to Nejat, N..

3 recordsLinked to original sources

bioRxiv2026

Infectious transgenesis in arthropods

In the last decade, there has been an explosion in the development of in vivo germline genetic editing technologies in arthropods, first pioneered by the Receptor-Mediated Ovary Transduction of Cargo (ReMOT Control) method. While ReMOT Control and related technologies (DIPA-CRISPR and SYNCAS) have shown great utility for gene knock-out in many different species, consistent gene insertion has been elusive, limiting widespread adoption. We developed a novel system based on the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) to deliver heritable CRISPR knock-out and knock-in constructs to the arthropod germline by oral feeding. We call this method "Germline Engineering by Viral Transduction" ("GEValT"). With GEValT, newly-eclosed female and male adult arthropods are fed on virus in sugar (and/or blood) and allowed to breed, resulting in easy generation of genetically modified offspring. GeValT is easy to use and has the potential to revolutionize gene editing methodology for researchers working across diverse arthropod species.

molecular biology↗

bioRxiv2025

Hologenomic structure of bacterial and fungal community composition in the West Nile virus vector Culex tarsalis

BackgroundMicrobiota play a crucial role in determining the ability for arthropod disease vectors to transmit pathogens. Microbial community structure can be heavily influenced by microbe-microbe interactions, host genetics and environmental factors. Here, we characterize the host population genetic structure, and bacterial and fungal communities in natural populations of the West Nile virus mosquito vector Culex tarsalis. Mosquitoes were collected and analyzed across the species range of the mosquito in the United States, where we used PoolRADSeq to quantify population genetic structure. Microbial community composition was characterized using bacterial 16S rRNA gene sequencing (V3-V4 region) and fungal ITS sequencing (ITS1 region). ResultsPoolRADSeq identified four broad genetic clusters of mosquito populations, which corresponded to previous clusters identified by microsatellite analysis and RADSeq on individual mosquitoes. Microbiome diversity grouped mosquito populations into three broad clusters, with each cluster distinctively represented by diagnostic abundant bacteria (Ralstonia, Pseudomonas, or Zymobacter/Providencia, respectively). Clustering for fungal taxa was less pronounced. Geographic distance between populations was positively correlated with microbiome community dissimilarity, and multiple environmental factors were significantly correlated with microbial species richness and diversity. ConclusionsThese results suggest that bacterial and fungal communities are geographically structured in Cx. tarsalis, interact with important environmental factors, and are partially correlated with host genetic structure. As microbiota can affect the ability for mosquitoes to transmit pathogens, understanding the factors underpinning microbiome variation across space and time has important implications for the spread of vector-borne pathogens such as WNV.

ecology↗

bioRxiv2022

High throughput peptidomics elucidates immunoregulatory functions of plant thimet oligopeptidase-directed proteostasis

Targeted proteolysis activities activated during the plant immune response catalyze the synthesis of stable endogenous peptides. Little is known about their biogenesis and biological roles. Herein, we characterize an Arabidopsis thaliana mutant top1top2 in which targeted proteolysis of immune-active peptides is drastically impaired during effector-triggered immunity (ETI). For effective ETI, the redox-sensitive thimet oligopeptidases TOP1 and TOP2 are required. Quantitative mass spectrometry-based peptidomics allowed differential peptidome profiling of wild type (WT) and top1top2 mutant at the early ETI stages. Biological processes of energy-producing and redox homeostasis were enriched, and TOPs were necessary to maintain the dynamics of ATP and NADP(H) accumulation in the plant during ETI. Subsequently, a set of novel TOPs substrates validated in vitro enabled the definition of the TOP-specific cleavage motif and informed an in-silico model of TOP proteolysis to generate bioactive peptide candidates. Several candidates, including those derived from proteins associated with redox metabolism, were confirmed in planta. The top1top2 background rescued WTs ETI deficiency caused by treatment with peptides derived from targeted proteolysis of the negative immune regulator FBR12, the reductive enzyme APX1, the isoprenoid pathway enzyme DXR, and ATP-subunit {beta}. These results demonstrate TOPs role in orchestrating the production and degradation of phytocytokines.

plant biology↗