Biology subjects

Zemach, A.

Publications and source records attributed to Zemach, A..

5 recordsLinked to original sources

bioRxiv2026

From Metabolomics to Function: Ranking Plant Stem Cell Metabolomes for Use in Health and Cosmetics

BackgroundPlants produce diverse metabolites with potential benefits for human health. However, the metabolomes of plant callus cultures--cell cultures analogous to stem cells--remain poorly characterized in terms of their functional relevance. MethodsWe profiled the metabolomes of six plant calli: Acacia concinna (Shikakai), Daucus carota (carrot), Hibiscus sabdariffa (hibiscus), Linum usitatissimum (flax), Ocimum sanctum (tulsi), and the Nicotiana tabacum Bright-Yellow 2 (BY-2) cell line. To facilitate functional interpretation, we developed Metabolite2Function (M2F), a pipeline that annotates metabolites with biological functions using scientific literature and large language modeling. ResultsUntargeted metabolomics identified 177 metabolites, revealing clustering patterns independent of genetic relationships, culture age, or growth rate. Tulsi and carrot calli exhibited enrichment in metabolites relative to the tobacco reference line, whereas flax and hibiscus were comparatively depleted. Most metabolites varied across at least four calli, and 10% were unique to a single species. Using M2F, we annotated 87 metabolites with beneficial activities, including antioxidant, anti-glycation, anti-inflammatory, and anti-senescence functions, as well as skin-related effects such as collagen production and brightening. Notably, antioxidant and anti-senescence metabolite levels correlated with corresponding biological activities in human cells. ConclusionsPlant callus cultures generate distinct and functionally diverse bioactive metabolomes. M2F provides a scalable framework for systematic functional annotation relevant to human health and cosmetic applications.

biochemistry↗

bioRxiv2026

Yeast-Plant-Derived Consortia Factors Exhibit A Distinct And Enriched Beneficial Metabolome For Health And Beauty

Cells secrete metabolites and other factors into the extracellular medium, collectively referred to as the secretome. The effect of co-culturing cells from different species on their combined secretome remains poorly understood. Here, we investigated the effect of co-culturing plant and yeast cells to produce a unique set of secretory factors collectively termed Consortia Factors (CFx). Specifically, a yeast suspension of Ustilago cynodontis (Ustilago) was co-cultured with plant cells derived from Ocimum sanctum (Tulsi). The metabolome of the Ustilago-Tulsi CFx (termed CFx-1) was then profiled and compared with that of the individual cultures. Statistical clustering analyses revealed that the CFx-1 metabolome was substantially different from either culture grown alone and was enriched in metabolites relative to single cultures. Notably, significant enrichment was observed among metabolites mutually upregulated in CFx compared with both single cultures, with approximately one-third absent from either culture alone. Using an algorithm designed to identify scientifically validated antioxidant metabolites, the CFx-1 was found to be enriched in antioxidants relative to the single cultures, including vitamin C. Accordingly, the CFx-1 exhibited stronger antioxidant activity than either of the single-culture secretomes, and even than the combination of the two single-culture secretomes. These findings suggest that consortia factors derived from co-culturing yeast and plant cells can generate a unique and more potent secretome that is enriched in bioactive metabolites beneficial for human health.

cell biology↗

bioRxiv2020

Processive and stochastic CHH methylation by plant DRM2 and CMT2 revealed by single-read methylome analysis

Cytosine methylome data is commonly generated through next-generation sequencing (NGS). Analyses of this data average methylation states of individual reads. We propose an alternate method of analysing single-read methylome data. Using this method, we identified patterns that relate to the mechanism of two plant non-CG methylating enzymes, DRM2 and CMT2: DRM2 has higher processivity than CMT2, and DRM2-methylated regions have higher variation among cells. Based on these patterns, we developed a classifier that predicts enzyme activity in different species and tissues. To facilitate further single-read analyses, we developed a genome browser optimised for visualising and analysing NGS data at single-read resolution.

plant biology↗

bioRxiv2020

Non-CG methylation is superior to CG methylation in genome regulation

DNA methylation in plants occurs in CG, CHG, and CHH sites. While depletion of CG methylation in transposons is associated with ample transcriptional activation, it was mainly studied in species with limited non-CG methylation that is linked to CG methylation. Here we profiled transcription in the moss plant, Physcomitrella patens, that has robust non-CG methylation with similar symmetrical CG and CHG methylation levels. Separated contextual methylation mechanisms in Physcomitrella patens enabled generation of numerous context-specific hypomethylated mutants. Our transcriptome data show that specific elimination of CG methylation is fully complemented by non-CG methylation. Conversely, exclusive removal of non-CG methylation massively dysregulated genes and transposons. Moreover, CHG methylation silenced transposons stronger than CG methylation. Lastly, we found non-CG methylation as crucial for silencing CG-depleted transposons. These results demonstrate the potency of non-CG methylation in genome regulation and suggest that it evolved due to moderate silencing and/or rapid mutability of methylated CGs.

genomics↗

bioRxiv2018

CMT3 and SUVH4/KYP silence the exonic retroelement Evelknievel to allow for reconstitution of CMT1 mRNA

Highlights: O_LISilencing of the intragenic Evelknievel (EK) retroelement is maintained by CMT3-KYP/SUVH4 independently of DDM1 and the RdDM pathways.\nC_LIO_LIMethylation and silencing of EK is required for transcription through the EK retroelement.\nC_LIO_LISilencing of EK allows for splicing out of the entire EK and reconstitution of an intact CMT1 mRNA.\nC_LI\n\nBackgroundCHROMOMEHYLASE1 (CMT1) has long been considered a non-essential gene because, in certain Arabidopsis ecotypes, the CMT1 gene is disrupted by the retroelement Evelknievel (EK), inserted within exon 13, or contains frame-shift mutations resulting in a truncated, non-functional protein. Here, we wanted to explore the regulatory pathway responsible for EK silencing in the Ler ecotype and its effect on CMT1 transcription.\n\nResultsMethylome databases confirmed that EK retroelement is heavily methylated but methylation is extended toward CMT1 downstream region. Strong transcriptional activation of EK accompanied by significant reduction in non-CG methylation was found in cmt3 and kyp2, but not in ddm1 or RdDM mutants. EK activation in cmt3 and kyp2 did not interfere with upstream CMT1 expression but abolish transcription through the EK. We identified, in wild type Ler, three spliced variants in which the entire EK is spliced out; one variant (25% of splicing incidents) facilitates proper reconstitution of an intact CMT1 mRNA. We could recover very low amount of the full length CMT1 mRNA from WT Ler and Col but not from cmt3 mutant..\n\nConclusionsOur findings highlight CMT3-SUVH4/KYP as the major pathway silencing the intragenic EK via inducing non-CG methylation. Furthermore, retroelement insertion within exons (e.g., CMT1) may not lead to a complete abolishment of the gene product when the element is kept silent. Rather the element can be spliced out to bring about reconstruction of a very low level of an intact, functional mRNA and possibly to retrieval of an active protein.

plant biology↗