Genomic data reveal ancient microendemism in forest scorpions across the California Floristic Province

The California Floristic Province (CFP) in western North America is a globally significant biodiversity hotspot. Elucidating patterns of endemism and the historical drivers of this diversity has been an important challenge of comparative phylogeography for over two decades. We generated phylogenomic data using ddRADseq to examine genetic structure in Uroctonus forest scorpions, an ecologically restricted and dispersal‐limited organism widely distributed across the CFP north to the Columbia River. We coupled our genetic data with species distribution models (SDMs) to determine climatically suitable areas for Uroctonus both now and during the Last Glacial Maximum. Based on our analyses, Uroctonus is composed of two major genetic groups that likely diverged over 2 million years ago. Each of these groups itself contains numerous genetic groups that reveal a pattern of vicariance and microendemism across the CFP. Migration rates among these populations are low. SDMs suggest forest scorpion habitat has remained relatively stable over the last 21 000 years, consistent with the genetic data. Our results suggest tectonic plate rafting, mountain uplift, river drainage formation and climate‐induced habitat fragmentation have all likely played a role in the diversification of Uroctonus. The intricate pattern of genetic fragmentation revealed across a temporal continuum highlights the potential of low‐dispersing species to shed light on small‐scale patterns of biodiversity and the underlying processes that have generated this diversity in biodiversity hotspots.     

Exploring Spatiotemporal Patterns of Phoma Black Stem in Sunflower

Field experiments were conducted over two growing seasons with three sunflower cultivars to explore the spatiotemporal dynamics of phoma black stem epidemics and to test hypotheses pertaining to (i) disease spread from a known inoculum source; (ii) spatial patterns of the disease; (iii) disease spatiotemporal association; and (iv) association between disease intensity and sunflower defoliation. The spatial patterns of disease were random in most of epidemics, and disease gradients were not detected. Our results suggest absence of secondary infections, that is, that the studied phoma black stem epidemics were monocyclic under the experimental conditions reported here. Significant associations between the number of dead leaves per plant and the number of phoma black stem lesions per plant were detected towards the end of epidemics.     

High‐yield secretion of recombinant proteins expressed in tobacco cell culture with a designer glycopeptide tag: Process development

Low‐yield protein production remains the most significant economic hurdle with plant cell culture technology. Fusions of recombinant proteins with hydroxyproline‐O‐glycosylated designer glycopeptide tags have consistently boosted secreted protein yields. This prompted us to study the process development of this technology aiming to achieve productivity levels necessary for commercial viability. We used a tobacco BY‐2 cell culture expressing EGFP as fusion with a glycopeptide tag comprised of 32 repeat of ”Ser‐Pro“ dipeptide, or (SP)₃₂, to study cell growth and protein secretion, culture scale‐up, and establishment of perfusion cultures for continuous production. The BY‐2 cells accumulated low levels of cell biomass (～7.5 g DW/L) in Schenk & Hildebrandt medium, but secreted high yields of (SP)₃₂‐tagged EGFP (125 mg/L). Protein productivity of the cell culture has been stable for 6.0 years. The BY‐2 cells cultured in a 5‐L bioreactor similarly produced high secreted protein yield at 131 mg/L. Successful operation of a cell perfusion culture for 30 days was achieved under the perfusion rate of 0.25 and 0.5 day^?1, generating a protein volumetric productivity of 17.6 and 28.9 mg/day/L, respectively. This research demonstrates the great potential of the designer glycopeptide technology for use in commercial production of valuable proteins with plant cell cultures.     

LH-releasing activity of potent LH-RH analogs in vitro

The LH-releasing activity of eight superactive analogs of LH-RH was measured in pituitary cells in primary culture. Introduction of the C-terminal ethylamide modification into [D-Ala⁶]- and [D-Leu⁶]-LH-RH (two peptides already 3 times more active than LH-RH) increases their activities 10-fold. [D-Phe⁶]- and [D-Trp⁶]-LH-RH are 90 and 100 times more active than LH-RH, respectively. The ethylamide derivatives of these two compounds are however approximately six times less active than the parent peptides.     

The metaphase chromosome: functional inertia and ability related to the presence of sequences of single-stranded DNA

Isolated metaphase chromosomes from KB cells were used as template in an in vitro DNA synthesis assay. In these conditions, no synthesis was noticed, confirming template inactivity of isolated metaphase chromosomes. DNA synthesis was noticed after a pretreatment with either methanol-acetic acid or RNase A. Analysis of in vitro synthesized polydeoxyribonucleotides showed two fractions of 4 S and 7-8 S. These results suggest the presence in metaphase chromosome of single stranded DNA sequences. Such sequences are shown in DNA extracted from chromosomes. They would preexist in this organelle and would be unmasked by the treatments that restore template activity of metaphase chromosome.     

Heterogeneous distribution of nuclear triiodothyronine receptors in liver and preadipose cells as evidenced by their reactivity to antibodies against different protein products of erb A oncogenes

Polyclonal antibodies raised in rabbits against bacterially produced peptides in the C-terminal region of v-erb A or human c-erb A oncogenes recognize the nuclear triiodothyronine (T3) receptors in the T3-sensitive Ob 17 mouse preadipocyte cell line and not in mouse or rat liver. The results confirm the existence of different T3 receptors in different tissues. The results also suggest a heterogeneous receptor distribution within the preadipose cell line, with a predominance of c-erb A-type species. Antibodies raised against domain 149–227, but not against domain 245–325, impair T3 binding, suggesting a role for this domain in ligand binding.