Biology subjects

Schultz, F.

Publications and source records attributed to Schultz, F..

3 recordsLinked to original sources

bioRxiv2022

Rapid evolution of flower phenology and clonality in restored populations of multiple grassland species

Restoration of terrestrial ecosystems often requires re-introduction of plants. In restored sites, the plants often face environment that differs from the one in natural populations. This which can affect plant traits, reduce performance and impose novel selection pressures. As a response, restored populations might rapidly evolve and adapt to the novel conditions. This may enhance population survival and contribute to restoration success, but has been rarely tested so far. Here, we focused on populations of three grassland species restored 20 years ago (Galium wirtgenii, Inula salicina and Centaurea jacea) by the transfer of green hay, and compared them with populations that were source of the hay. We measured plants both in-situ, and in common garden under control and three stress conditions. In-situ, restored and natural populations differed in flowering phenology in two out of the three species. In the common garden, plants of the restored population flowered earlier (in Galium) or showed increased plasticity of clonal propagation in response to clipping (Inula). Both these traits suggest rapid adaptation to the contrasting mowing regimes in restored in comparison to the natural donor sites. In Centaurea, we detected no differentiation, neither in-situ, nor in the common garden. Rapid evolution in two out of three species indicates that evolution in restoration may be rather common, yet not ubiquitous across species.

evolutionary biology↗

bioRxiv2022

Humanized NBSGW PDX Models of Disseminated Ovarian Cancer Recapitulate Key Aspects of the Tumor Immune Environment within the Peritoneal Cavity

The importance of the immune microenvironment in ovarian cancer progression, metastasis, and response to therapies has become increasingly clear, especially with the new emphasis on immunotherapies. In order to leverage the power of patient-derived xenograft (PDX) models within a humanized immune microenvironment, three ovarian cancer PDX were grown in humanized NBSGW mice engrafted with human CD34+ cord blood-derived hematopoietic stem cells. Analysis of cytokine levels in the ascites fluid and infiltrating immune cells in the tumors demonstrated that these humanized PDX (huPDX) established an immune tumor microenvironment similar to what has been reported for ovarian cancer patients. The lack of human myeloid cell differentiation has been a major setback for humanized mouse models, but our analysis shows that PDX engraftment increases the human myeloid population in the peripheral blood. Analysis of cytokines within the ascites fluid of huPDX revealed high levels of human M-CSF, a key myeloid differentiation factor as well as other elevated cytokines that have previously been identified in ovarian cancer patient ascites fluid including those involved in immune cell differentiation and recruitment. Human tumor-associated macrophages and tumor-infiltrating lymphocytes were detected within the tumors of humanized mice, demonstrating immune cell recruitment to tumors. Comparison of the three huPDX revealed certain differences in cytokine signatures and in the extent of immune cell recruitment. Our studies show that huNBSGW PDX models reconstitute important aspects of the ovarian cancer immune tumor microenvironment making this a superior approach for therapeutic trials.

cancer biology↗

bioRxiv2022

Molecular cloning and recombinant protein expression of 9-Lipoxygenase gene from Solanum tuberosum in Pichia pastoris yeast cells

Synthetic fungicides have effectively controlled plant pathogenic fungi but their continued use has been detrimental to natural biological systems, and sometimes resulted into development of fungal resistance. They also have undesirable effects on non-target organisms and foster environmental and human health concerns thus new biodegradable alternatives have to be investigated. Lipoxygenases (LOX) are ubiquitous non-heme Iron containing dioxygenases that catalyze the addition of molecular oxygen to Polyunsaturated Fatty Acids (PUFAs) such as Linoleic acid to form Oxylipins that possess anti-microbial activity.The aim of this study was to generate a recombinant 9-Lipoxygenase protein for chemo enzymatic synthesis of Oxylipin based biodegradable fungicides. Golden gate assembly, a molecular cloning method that allows assembly of many DNA fragments into a complete piece using Type II s restriction enzymes and T4 DNA ligase was used to clone the complete 9-LOX gene into the expression plasmid vector pPICZB. Protein expression in Pichia pastoris yeast cells was induced by addition of absolute methanol every after 24h for up to four days. Analysis of protein expression from cell lysates was achieved by SDS-PAGE and Western blotting probed with anti-histidine antibody which showed putative protein bands of 97kDa representing recombinant 9-LOX protein. It is recommended that optimization studies on the yeast kex2 convertase and the - secretion factor can be done to enable secretion of recombinant Solanum tuberosum 9-LOX protein since the protein in this study was recovered from cell lysates.

molecular biology↗