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Aim: study of immediate and long-term results of the surgical treatment of the locally advanced pancreatic cancer with tumor invasion of the main veins of the abdominal cavity. Material and methods. Pancreaticoduodenectomy with resection and plasty of the main veins of the abdominal cavity were performed 315 patients. 143 patients underwent for prosthetics of the main veins at their reconstruction of different vascular prosthesis. Patients have been divided into three groups. Group I (basic) — PTFE-conduits have been used in the reconstruction of the main veins (82 patients). Group II — FLL-conduits have been used in the reconstruction of the main veins (36 patients). Group III — autovenous conduits have been used in the reconstruction of the main veins (25 patients). Comparison of the duration of operation and its reconstruction stage, the quantity of blood loss, frequency of venous thrombosis in the early postoperative period and long-term patency of the reconstructed veins traced ultrasonic method in a period of 6 months, 1, 2, and 3 years after surgery have been carried. The morbidity, the frequency of the infectious complications, the hospital mortality, the mean postoperative hospital stay, median of survival have been studied after surgery. Results. Application of the PTFE-conduits resulted for decrease of the duration of the reconstruction stage of the operation, as well as the duration of the surgery and the amount of intraoperative blood loss. Decrease of the morbidity, of the postoperative hospital stay and the mortality have been noted in the I group of patients compared to groups II and III patients. Thrombosis of the prosthesis after reconstruction of the veins that led for fatal outcome has been marked in 2 patients (5.5%) in group II of the patients. The long-term patency of vascular PTFE-conduits and reconstructed veins in group 1 has been 100% in all period's observations in the postoperative period. Conclusion. PTFE-conduits are universal plastic material. Application of the PTFE-conduits for the reconstruction of the main veins of the mesenteric-portal system can reduce the duration of the reconstruction vascular stage and the operation as a whole. Applications of the PTFE-conduits reduce the morbidity, the frequency of infectious complications, postoperative hospital-stay, hospital mortality, as well as improved performance patency of the reconstructed vessels.

Clathrin-mediated endocytosis (CME) requires energy input from actin polymerization in mechanically challenging conditions. The roles of actin in CME are poorly understood due to inadequate knowledge of actin organization at clathrin-coated structures (CCSs). Using platinum replica electron microscopy of mammalian cells, we show that Arp2/3 complex-dependent branched actin networks, which often emerge from microtubule tips, assemble along the CCS perimeter, lack interaction with the apical clathrin lattice, and have barbed ends oriented toward the CCS. This structure is hardly compatible with the widely held "apical pulling" model describing actin functions in CME. Arp2/3 complex inhibition or epsin knockout produce large flat non-dynamic CCSs, which split into invaginating subdomains upon recovery from Arp2/3 inhibition. Moreover, epsin localization to CCSs depends on Arp2/3 activity. We propose an "edge pushing" model for CME, wherein branched actin polymerization promotes severing and invagination of flat CCSs in an epsin-dependent manner by pushing at the CCS boundary, thus releasing forces opposing the intrinsic curvature of clathrin lattices., (© 2022. The Author(s).)

Increasing demands for protein-based therapeutics such as monoclonal antibodies, fusion proteins, bispecific molecules, and antibody fragments require researchers to constantly find innovative solutions. To increase yields and decrease costs of next generation bioprocesses, highly concentrated cell culture media formulations are developed but often limited by the low solubility of amino acids such as tyrosine, cystine, leucine, and isoleucine, in particular at physiological pH. This study sought to investigate highly soluble and bioavailable derivatives of leucine and isoleucine that are applicable for fed-batch processes. N-lactoyl-leucine and N-lactoyl-isoleucine sodium salts were tested in cell culture media and proved to be beneficial to increase the overall solubility of cell culture media formulations. These modified amino acids proved to be bioavailable for various Chinese hamster ovary (CHO) cells and were suitable for replacement of canonical amino acids in cell culture feeds. The quality of the final recombinant protein was studied in bioprocesses using the derivatives, and the mechanism of cleavage was investigated in CHO cells. Altogether, both N-lactoyl amino acids represent an advantageous alternative to canonical amino acids to develop highly concentrated cell culture media formulations to support next generation bioprocesses., (© 2021 Merck KGaA. Biotechnology and Bioengineering published by Wiley Periodicals LLC.)

Prokaryotes utilize polycistronic messages (operons) to co-translate proteins involved in the same biological processes. Whether eukaryotes achieve similar regulation by selectively assembling and translating monocistronic messages derived from different chromosomes is unknown. We employed transcript-specific RNA pulldowns and RNA-seq/RT-PCR to identify yeast mRNAs that co-precipitate as ribonucleoprotein (RNP) complexes. Consistent with the hypothesis of eukaryotic RNA operons, mRNAs encoding components of the mating pathway, heat shock proteins, and mitochondrial outer membrane proteins multiplex in trans, forming discrete messenger ribonucleoprotein (mRNP) complexes (called transperons ). Chromatin capture and allele tagging experiments reveal that genes encoding multiplexed mRNAs physically interact; thus, RNA assembly may result from co-regulated gene expression. Transperon assembly and function depends upon histone H4, and its depletion leads to defects in RNA multiplexing, decreased pheromone responsiveness and mating, and increased heat shock sensitivity. We propose that intergenic associations and non-canonical histone H4 functions contribute to transperon formation in eukaryotic cells and regulate cell physiology., Competing Interests: RN, DZ, RG, BH, MD, HS, JG No competing interests declared, CN Chad Nusbaum is affiliated with Cellarity Inc. The author has no financial interests to declare., (© 2021, Nair et al.)

In experimental evolution, scientists evolve organisms in the lab, typically by challenging them to new environmental conditions. How best to evolve a desired trait? Should the challenge be applied abruptly, gradually, periodically, sporadically? Should one apply chemical mutagenesis, and do strains with high innate mutation rate evolve faster? What are ideal population sizes of evolving populations? There are endless strategies, beyond those that can be exposed by individual labs. We therefore arranged a community challenge, Evolthon, in which students and scientists from different labs were asked to evolve Escherichia coli or Saccharomyces cerevisiae for an abiotic stress-low temperature. About 30 participants from around the world explored diverse environmental and genetic regimes of evolution. After a period of evolution in each lab, all strains of each species were competed with one another. In yeast, the most successful strategies were those that used mating, underscoring the importance of sex in evolution. In bacteria, the fittest strain used a strategy based on exploration of different mutation rates. Different strategies displayed variable levels of performance and stability across additional challenges and conditions. This study therefore uncovers principles of effective experimental evolutionary regimens and might prove useful also for biotechnological developments of new strains and for understanding natural strategies in evolutionary arms races between species. Evolthon constitutes a model for community-based scientific exploration that encourages creativity and cooperation., Competing Interests: The authors have declared that no competing interests exist.

Mitochondria are thought to have evolved from ancestral proteobacteria and, as a result of symbiosis, became an indispensable organelle in all eukaryotic cells. Mitochondria perform essential functions that provide the cell with ATP, amino acids, phospholipids, and both heme and iron-sulfur clusters. However, only 1% of mitochondrial proteins are encoded by the mitochondrial genome, while the remaining 99% are encoded in the nucleus. This raises a logistical challenge to the cell, as these nuclear-encoded proteins have to be translated, delivered to the mitochondrial surface, and translocated to its various compartments. Over the past decade, it was shown that subsets of mRNAs encoding mitochondrial proteins (mMPs) are localized to the mitochondrial surface in both yeast and mammalian cells. Moreover, factors (e.g., RNA-binding proteins) have been discovered that facilitate mMP targeting, and their loss leads to RNA mislocalization and defects in mitochondrial function (e.g., deficient respiration). Therefore, there is a demand in the field of mitochondrial biology to accurately measure mMP localization to the mitochondrial surface. In this chapter, we describe two techniques that allow for the visualization of mMPs using single-molecule fluorescent in situ hybridization and preparation of a highly enriched mitochondrial fraction followed by quantitative real-time PCR. Together, these techniques constitute powerful tools to link changes in mMP trafficking to defects in mitochondrial physiology.

Nuclear-encoded mRNAs encoding mitochondrial proteins (mMPs) can localize directly to the mitochondrial surface, yet how mMPs target mitochondria and whether RNA targeting contributes to protein import into mitochondria and cellular metabolism are unknown. Here, we show that the COPI vesicle coat complex is necessary for mMP localization to mitochondria and mitochondrial function. COPI inactivation leads to reduced mMP binding to COPI itself, resulting in the dissociation of mMPs from mitochondria, a reduction in mitochondrial membrane potential, a decrease in protein import in vivo and in vitro, and severe deficiencies in mitochondrial respiration. Using a model mMP (OXA1), we observed that COPI inactivation (or mutation of the potential COPI-interaction site) led to altered mRNA localization and impaired cellular respiration. Overall, COPI-mediated mMP targeting is critical for mitochondrial protein import and function, and transcript delivery to the mitochondria or endoplasmic reticulum is regulated by cis-acting RNA sequences and trans-acting proteins., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)