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Congratulations to our member Prof. Tzion Fahima who was recognized by the US-Israel Binational Agricultural Research and Development Fund (BARD), as world-class contributors to combating food insecurity.

LAST PUBLICATIONS

Main findings: Spalax fibroblasts undergo replicative senescence and etoposide‐induced senescence, evidenced by an increased activity of SA‐β‐Gal, growth arrest, and increased p21, p16, and p53 (Fig. A);
Yet, unlike mouse and human fibroblasts, Spalax senescent cells showed undetectable or decreased expression of the well‐known SASP factors (Fig. B);
High efficiency of DNA repair is responsible to suppression of inflammatory response in Spalax (Fig C);
Downregulation of SASP secretion in Spalax senescent fibroblasts is associated, at list in part with suppression of IL1α cytokine response and inhibition of NF-kB translocation to the nuclei (Figs. D and E); Evaluation of SASP in ageing Spalax tissues confirmed downregulation of inflammatory‐related genes (Fig. F)

Odeh, A., Dronina, M., Domankevich, V., Shams, I ., Manov, I. 2020. Downregulation of the inflammatory network in senescent fibroblasts and aging tissues of the long‐lived and cancer‐resistant subterranean wild rodent, Spalax . Aging Cell, 19(1):e13045

The uncoupling of senescence phenotype and the inflammatory component of SASP (senescent-associated secretory phenotype) was discovered in long‐lived blind mole rat, Spalax, adapted to extreme environments. Cellular senescence in Spalax, evidenced by increased SA‐β‐Gal activity, upregulation of p21/p16/p53, is not accompanied by accumulation of DNA damage nor by secretion of SASP factors. We suggest that genome integrity, inhibition of NF‐κB nuclear translocation, and IL1α suppression are involved in overcoming the inflammatory response in aging Spalax.

We propose that suppression of SASP in senescent Spalax cells, as well as inhibition of inflammation in aging Spalax, can support a nonpermissive microenvironment for cancer progression, as well as the suppression of sterile inflammation, which is the cause of most aging‐related pathologies

Schematic diagram showing the differences between canonical inflammatory SASP (human / mouse) and non-inflammatory secretome (NIS) in Spalax and their effects on homeostasis in aging tissues.

Manov, I., Odeh, A., Shams, I .2020. Aging without inflammaging. Aging (Albany NY), 12(16):15875-15877

Canonical secretome of senescent cells comprises a specific pattern of inflammatory mediators and growth factors that may induce senescence in surrounding cells, an effect known as "bystander senescence". The accumulation of senescent cells in aging leads to the amplification of SASP, which in turn modulates the surrounding tissues and causes the so-called "sterile inflammation"- a microenvironment that supports most age-related pathologies, including malignant neoplasms. Due to the efficient DNA repair and other mechanisms, Spalax senescent cells do not produce the main inflammatory factors that are involved in the development of age-related pathologies. Hence, when these cells transmit senescence to surrounding cells via the paracrine factors of "non-inflammatory secretome" (NIS), the recipient cells also do not elicit an inflammatory response and therefore cannot maintain "sterile inflammation" and cancer development in older Spalax.

Shams, I. and Raskina, O. 2020. Supernumerary B chromosomes and plant genome changes: A snapshot of wild populations of Aegilops speltoides Tausch (Poaceae, Triticeae). International Journal of Molecular Sciences, 21 (11): 3768 https://doi.org/10.3390/ijms21113768

In various eukaryotes, supernumerary B chromosomes (Bs) are an optional genomic component. The notable features of Bs are variability in numbers among individuals, species-specific organization, and enrichments with different types of repetitive DNA; and the inheritance of the B chromosome is not subject to Mendelian laws. The origin of Bs is still obscure, but studies employing recent advances in next-generation sequencing indicate that they arise as a result of A chromosome rearrangements, and some genes of standard A chromosomes remain transcriptionally active in Bs.

In the present study, the impact of Bs on the current changes in the genome of goatgrass, Aegilops speltoides, which is a wild progenitor of the B and G genomes of allopolyploid wheats, was addressed. We focused on the cytogenetic features of Bs and the intra-organismal copy number dynamics of retrotransposons (TEs) and species-specific tandem repeat (TR) in plants with and without Bs in highly heterogeneous populations of Ae. speltoides. Our data indicate that fluctuations in TE and TR copy numbers are associated with DNA damage and repair processes during cell proliferation and differentiation, and ectopic recombination is one of the mechanisms by which Bs play a role in genome changes.

Variability in the copy numbers of the Angela, Wilma, and Stasy retrotransposons and Spelt1 tandem repeat in somatic and generative tissues of the spike in individual genotypes

Fluctuations in the total TE and TR copy number between different tissues of one spike is phenomenon that is indicative of the efficacy of DNA repair during cell proliferation and differentiation.

Somatic recombination is associated with DNA replication and repair processes and is tightly interlinked with individual chromosome positioning and dynamics in interphase nuclei. The involvement of ectopic repetitive sequences in the repair of DNA damage is a complementary process both in plant mitosis and meiosis.

Rearrangements of B chromosomes (C) and ectopic

B-A chromosome associations (D) in somatic cells.

Ectopic association between A and B chromosomes in meiosis at the anaphase I stage (arrow).

Ectopic recombination, which causes chromosomal rearrangements, may also prevent harmful aberrations, and, above all, double-stranded DNA breaks (DSBs), and therefore, it is vitally important for the cell.

In this regard, supernumerary B chromosomes serve as an additional template in DNA repair, especially in heterochromatin and clusters of various repetitive sequences, specifically, various transposable elements that are distributed throughout the euchromatin. Vice versa, standard A chromosomes contribute to ectopic DNA repair in Bs, and contribute to the accumulation of sequences of standard chromosomes in Bs during both somatic and meiotic cell proliferation.

Congratulations to our former student Dr. Zhenzhen Wei for her first, but not last, PhD publication !!!

https://www.mdpi.com/2076-0817/9/6/418

Scientific Seminars

The presented lectures deal mainly with the hot topics in evolutionary biology, molecular genetics, genomics, and ecology. The seminars are delivered by expert lecturers and distinguished visitors in a relaxed environment.

At this point, the seminars will be held online on Mondays at 12 pm .

2020/21 seminar series:

seminars 2020_21