Biology subjects

Saeedi, S.

Publications and source records attributed to Saeedi, S..

3 recordsLinked to original sources

bioRxiv2026

Hitchhiking Microplastics Through Mosquitoes as Unseen Vehicles of Terrestrial and Aerial Transfer: Experimental Evidence

BackgroundMicroplastic (MP) pollution is an emerging environmental concern that extends beyond aquatic systems into terrestrial food webs. The mosquito Anopheles stephensi, a major malaria vector in Asia and the Middle East, undergoes complete metamorphosis and offers a useful model to examine cross-stage MP transfer. However, the physiological consequences of such exposure remain poorly understood. MethodsFluorescent polystyrene microplastics (1 {micro}m) were administered at six concentrations (0-300 mg L-1) under controlled laboratory conditions. Larvae were reared on standard fish pellets, and adults were maintained on a 10% sucrose solution. Fluorescence microscopy tracked MP ingestion and transfer across life stages. Larval weight, developmental timing, and survival were analyzed using ANOVA and Chi-square tests. ResultsOntogenic transfer of microplastics was confirmed from larvae to pupae (100%) and adults (94%). Increasing MP concentrations accelerated development by 1-2 days but significantly reduced survival, with mortality rising from 12% in controls to 64% at 300 mg L-1. Body weight declined consistently in a dose-dependent manner (p < 0.001). ConclusionThis study provides the first experimental evidence of ontogenic MP transfer in An. stephensi. Microplastic exposure alters development and survival, potentially affecting mosquito population dynamics and vectorial capacity, highlighting the need to incorporate MP pollution into vector ecology models.

ecology↗

bioRxiv2025

Genome sequence of Talaromyces trachyspermus, a biocontrol fungus isolated from broomrape

Applying antimicrobial compounds derived from microorganisms for plant disease management is one of the objectives of sustainable agriculture. The genus Talaromyces is known for its species ability to produce a diverse group of antimicrobial compounds. For example, T. trachyspermus has been reported to produce secondary metabolites, cell wall-degrading enzymes, and plant growth-promoting factors. Identification of novel promising metabolites and enzymes from T. trachyspermus is still in its infancy. Also, there is a lack of information about the genomic resources for its secondary metabolites and hydrolytic enzymes. Therefore, this study aimed to analyse the genome of a biocontrol isolate of this species to investigate its biocontrol mechanisms at the genomic level, focusing on secondary metabolites and cell wall degrading enzymes. The whole genome of T. trachyspermus isolate IRAN 3054C, obtained from necrotic Orobanch ramosa stems in Iran with biocontrol ability, was sequenced using the Illumina platform. We performed both de novo and resequencing analyses of the genome, obtaining a 31.3 Mb assembly. The abundance of protein groups associated with biocontrol activities was assessed in the studied genome. Fungismash was used to detect and annotate secondary metabolites. The analysis revealed the presence of several secondary metabolite biosynthesis gene clusters (BGCs), with a high frequency of polyketide synthases (T1PKS) and nonribosomal peptide synthetases (NRPS), which are known to produce bioactive compounds with antimicrobial properties. Among the identified secondary metabolites, Fusarin, YWA1, Dimethylcoprogen, and Squalestatin S1 exhibited the highest similarity to known compounds. Furthermore, sequences similar to Phyllostictine A/B and Cornexistin indicate potential herbicidal properties. The genome also had domains for enzymes involved in phosphate solubilisation, siderophore production, and fungal cell wall degradation, which are essential for biocontrol and plant growth promotion. Our findings highlight the genomic richness of T. trachyspermus IRAN 3054C for biocontrol. Further metabolomics studies are needed to validate the actual production of these secondary metabolites and explore their functional roles in biocontrol.

genomics↗

bioRxiv2021

Neuron-derived extracellular vesicles extracted from plasma show altered size and miRNA cargo as a function of antidepressant drug response

Previous work has demonstrated that microRNAs (miRNAs) change as a function of antidepressant treatment (ADT) response. However, it is unclear how representative these peripherally detected miRNA changes are to those occurring in the brain. This study aimed to use peripherally extracted neuron-derived extracellular vesicles (NDEVs) to circumvent these limitations and investigate neuronal miRNA changes associated with antidepressant response. Samples were collected at two time points (baseline and after 8 weeks of follow-up) from depressed patients who responded (N=20) and did not respond (N=20) to escitalopram treatment, as well as controls (N=20). Total extracellular vesicles (EVs) were extracted from plasma, and then further enriched for NDEVs by immunoprecipitation with L1CAM. EV size was measured using tunable resistive pulse sensing, and NDEV miRNA cargo was extracted and sequenced. Subsequently, studies in cell lines and postmortem tissue were conducted. Characterization of NDEVs revealed they were smaller than other EVs isolated from plasma (p<0.0001), had brain-specific neuronal markers, and contained miRNAs enriched for brain functions (p<0.0001) Furthermore, NDEVs from depressed patients were smaller than controls (p<0.05), and NDEV size increased with ADT response (p<0.01). Finally, changes in NDEV cargo, specifically changes in miR-21-5p, miR-30d-5p and miR-486-5p together (p<0.01), were associated with ADT response. Targets of these three miRNAs were altered in brain tissue from depressed individuals (p<0.05). Together, this study indicates that changes in peripherally isolated NDEVs can act as both a clinically accessible and informative biomarker of ADT response specifically through size and cargo.

neuroscience↗