Quantifying Protein Dynamics by Kymograph Analysis.

Time-lapse imaging of the subcellular localization and dynamic behavior of proteins is critical to understand their biological functions in cells. With the advent of various methodologies and computational tools, the precise tracking and quantification of protein spatiotemporal dynamics have become feasible. Kymograph analysis, in particular, has been extensively adopted for the quantitative assessment of proteins, vesicles, and organelle movements. However, conventional kymograph analysis, which is based on a single linear trajectory, may not comprehensively capture the complexity of proteins that alter their course during intracellular transport and activity. In this chapter, we introduced an advanced protocol for whole-cell kymograph analysis that allows for three-dimensional (3D) tracking of protein dynamics. This method was validated through the analysis of tip-focused endocytosis and exocytosis processes in growing tobacco pollen tubes by employing both the advanced whole-cell and classical kymograph methods. In addition, we enhanced this method by integrating pseudo-colored kymographs that enables the direct visualization of changes in protein fluorescence intensity with fluorescence recovery after photobleaching to advance our understanding of protein localization and dynamics. This comprehensive method offers a novel insight into the intricate dynamics of protein activity within the cellular context.

Genetic Strategies and Mechanisms for Improving Ribonucleic Acid Levels of Saccharomyces pastorianus.

Developing microorganisms with a high ribonucleic acid (RNA) content is crucial for the RNA industry. Numerous studies have been conducted to enhance RNA production in yeast cells through genetic engineering, yet precise mechanisms remain elusive. Previously, upregulation of TAL1 or PGM2 and deleting PRS5 or DBP8 individually could increase the RNA content in Saccharomyces pastorianus. In this study, within these genetically modified strains, the intracellular nucleotide levels notably increased following cell fragmentation. Deletion of PRS5 and DBP8 within the strain prompted the upregulation of genes sharing similar functions, consequently augmenting the flow of the gene pathway. Furthermore, the upregulation of genes encoding cell-cycle-dependent protein kinases (CDK) was observed in the G03-△PRS5 strain. The influence of TAL1 and PGM2 on RNA content was attributed to the pentose phosphate pathway (PPP). The RNA content of polygenic recombinant strains, G03-△PRS5+△DBP8 and G03-△PRS5+△DBP8+PGM2, displayed the most significant improvement, increasing by 71.8 and 80.1% when compared to the parental strain. Additionally, the maximum specific growth rate of cells increased in these strains. This study contributes valuable insights into the genetic mechanisms underlying high nucleic acid synthesis in S. pastorianus.

Simultaneous Plate-Reader Characterization of Promoter Activity and Cell Growth in Engineered Mammalian Cells.

Automated high-throughput methods that support tracking of mammalian cell growth are currently needed to advance cell line characterization and identification of desired genetic components required for cell engineering. Here, we describe a high-throughput noninvasive assay based on plate reader measurements. The assay relies on the change in absorbance of the pH indicator phenol red. We show that its basic and acidic absorbance profiles can be converted into a cell growth index consistent with cell count profiles, and that, by adopting a computational pipeline and calibration measurements, it is possible to identify a conversion that enables prediction of cell numbers from plate measurements alone. The assay is suitable for growth characterization of both suspension and adherent cell lines when these are grown under different environmental conditions and treated with chemotherapeutic drugs. The method also supports characterization of stably engineered cell lines and identification of desired promoters based on fluorescence output.

CircMAN1A2_009 facilitates YBX1 nuclear localization to induce GLO1 activation for cervical adenocarcinoma cell growth.

The molecular mechanisms driving the development of cervical adenocarcinoma (CADC) and optimal patient management strategies remain elusive. In this study, we have identified circMAN1A2_009 as an oncogenic circular RNA (circRNA) in CADC. Clinically, circMAN1A2_009 showed significant upregulation in CADC tissues, with an impressive area under the curve value of 0.8075 for detecting CADC. Functional studies, involving both gain-of-function and loss-of-function experiments, revealed that circMAN1A2_009 suppressed reactive oxygen species accumulation and apoptosis, and boosted cell viability in CADC cells. Conversely, silencing circMAN1A2_009 reversed these effects. Further mechanistic investigations indicated that circMAN1A2_009 interacted with YBX1, facilitating the phosphorylation levels of YBX1 at serine 102 (p-YBX1S102) and facilitating YBX1 nuclear localization through sequence 245-251. This interaction subsequently increased the activity of the glyoxalase 1 (GLO1) promoter, leading to the activation of GLO1 expression. Consistently, inhibition of either YBX1 or GLO1 mirrored the biological effects of circMAN1A2_009 in CADC cells. Additionally, knockdown of YBX1 or GLO1 partially reversed the oncogenic behaviors induced by circMAN1A2_009. In conclusion, our findings propose circMAN1A2_009 as a potential oncogene and a promising indicator for diagnosing and guiding therapy in CADC patients.

The Prognostic Hub Gene POLE2 Promotes BLCA Cell Growth via the PI3K/AKT Signaling Pathway.

BACKGROUND: BLCA is a common urothelial malignancy characterized by a high recurrence rate. Despite its prevalence, the molecular mechanisms underlying its development remain unclear. AIMS: This study aimed to explore new prognostic biomarkers and investigate the underlying mechanism of bladder cancer (BLCA). OBJECTIVE: The objective of this study is to identify key prognostic biomarkers for BLCA and to elucidate their roles in the disease. METHODS: We first collected the overlapping DEGs from GSE42089 and TCGA-BLCA samples for the subsequent weighted gene co-expression network analysis (WGCNA) to find a key module. Then, key module genes were analyzed by the MCODE algorithm, prognostic risk model, expression and immunohistochemical staining to identify the prognostic hub gene. Finally, the hub gene was subjected to clinical feature analysis, as well as cellular function assays. RESULTS: In WGCNA on 1037 overlapping genes, the blue module was the key module. After a series of bioinformatics analyses, POLE2 was identified as a prognostic hub gene in BLCA from potential genes (TROAP, POLE2, ANLN, and E2F8). POLE2 level was increased in BLCA and related to different clinical features of BLCA patients. Cellular assays showed that si-POLE2 inhibited BLCA proliferation, and si-POLE2+ 740Y-P in BLCA cells up-regulated the PI3K and AKT protein levels. CONCLUSION: In conclusion, POLE2 was identified to be a promising prognostic biomarker as an oncogene in BLCA. It was also found that POLE2 exerts a promoting function by the PI3K/AKT signaling pathway in BLCA.

Atmospheric Pressure Plasma Functionalization of Sealed PDMS Microfluidics: Application to Capillary Pumping and Enhanced Cell Growth.

Microfluidic devices serve as essential tools across diverse fields like medicine, biotechnology, and chemistry, enabling advancements in analytical techniques, point-of-care diagnostics, microfluidic cell cultures, and organ-on-chip models. While polymeric microfluidics are favoured for their cost-effectiveness and ease of fabrication, their inherent hydrophobic properties necessitate surface functionalization, often post-sealing. Here, we introduce a versatile apparatus for functionalizing sealed microfluidic devices using atmospheric plasma processing, with a focus on PDMS (polydimethylsiloxane) microfluidics. Through meticulous analysis of surface properties and capillary velocity, before and after plasma treatment, along with a comparison between vacuum and atmospheric plasma functionalization methods, we demonstrate the efficacy of our approach. Subsequent experimentation within 3D PDMS microfluidic chambers, combining atmospheric pressure plasma treatment with collagen coating to facilitate mesenchymal stem cells (MSCs) growth over five days, reveals enhanced initial cell adhesion and proliferation, highlighting the potential of our method for improving cell-based applications within microfluidic systems.

A mechanohydraulic model supports a role for plasmodesmata in cotton fiber elongation.

Plant cell growth depends on turgor pressure, the cell hydrodynamic pressure, which drives expansion of the extracellular matrix (the cell wall). Turgor pressure regulation depends on several physical, chemical, and biological factors, including vacuolar invertases, which modulate osmotic pressure of the cell, aquaporins, which determine the permeability of the plasma membrane to water, cell wall remodeling factors, which determine cell wall extensibility (inverse of effective viscosity), and plasmodesmata, which are membrane-lined channels that allow free movement of water and solutes between cytoplasms of neighboring cells, like gap junctions in animals. Plasmodesmata permeability varies during plant development and experimental studies have correlated changes in the permeability of plasmodesmal channels to turgor pressure variations. Here, we study the role of plasmodesmal permeability in cotton fiber growth, a type of cell that increases in length by at least three orders of magnitude in a few weeks. We incorporated plasmodesma-dependent movement of water and solutes into a classical model of plant cell expansion. We performed a sensitivity analysis to changes in values of model parameters and found that plasmodesmal permeability is among the most important factors for building up turgor pressure and expanding cotton fibers. Moreover, we found that nonmonotonic behaviors of turgor pressure that have been reported previously in cotton fibers cannot be recovered without accounting for dynamic changes of the parameters used in the model. Altogether, our results suggest an important role for plasmodesmal permeability in the regulation of turgor pressure.

Cell growth monitoring in a tetrapolar electrode configuration.

There are various methods for cell growth monitoring. However, most of these methods have drawbacks, such as being invasive, not providing real-time results, or being costly. In this study, we present an alternate method of cell growth monitoring, which is low-cost, non-invasive, real-time, and uses Electrical Impedance Spectro-scopy (EIS). In this work, commercially available culture plates were fitted with custom tetrapolar electrodes, and mouse cells were cultured on them. The variation of culture media impedance, resulting from cell growth, proliferation and other metabolic activities, was recorded over a period of seven days. The results demonstrated an initial increase in impedance corresponding with the cell growth phase, followed by a decrease during the cell death (apoptosis) phase, as confirmed by microscope images. Overall, the results show that our method to monitor cell growth using tetrapolar electrodes is promising and can be further refined for related applications.

GA dynamics governing nodulation revealed using GIBBERELLIN PERCEPTION SENSOR 2 in Medicago truncatula lateral organs.

During nutrient scarcity, plants can adapt their developmental strategy to maximize their chance of survival. Such plasticity in development is underpinned by hormonal regulation, which mediates the relationship between environmental cues and developmental outputs. In legumes, endosymbiosis with nitrogen fixing bacteria (rhizobia) is a key adaptation for supplying the plant with nitrogen in the form of ammonium. Rhizobia are housed in lateral root-derived organs termed nodules that maintain an environment conducive to Nitrogenase in these bacteria. Several phytohormones are important for regulating the formation of nodules, with both positive and negative roles proposed for gibberellin (GA). In this study, we determine the cellular location and function of bioactive GA during nodule organogenesis using a genetically-encoded second generation GA biosensor, GIBBERELLIN PERCEPTION SENSOR 2 in Medicago truncatula. We find endogenous bioactive GA accumulates locally at the site of nodule primordia, increasing dramatically in the cortical cell layers, persisting through cell divisions and maintaining accumulation in the mature nodule meristem. We show, through mis-expression of GA catabolic enzymes that suppress GA accumulation, that GA acts as a positive regulator of nodule growth and development. Furthermore, increasing or decreasing GA through perturbation of biosynthesis gene expression can increase or decrease the size of nodules, respectively. This is unique from lateral root formation, a developmental program that shares common organogenesis regulators. We link GA to a wider gene regulatory program by showing that nodule-identity genes induce and sustain GA accumulation necessary for proper nodule formation.

CircHIPK2 Contributes Cell Growth in Intestinal Epithelial of Colitis and Colorectal Cancer through Promoting TAZ Translation.

Colorectal cancer (CRC) and inflammatory bowel disease (IBD) are escalating global health concerns. Despite their distinct clinical presentations, both disorders share intricate genetic and molecular interactions. The Hippo signaling pathway plays a crucial role in regulating cell processes and is implicated in the pathogenesis of IBD and CRC. Circular RNAs (circRNAs) have gained attention for their roles in various diseases, including IBD and CRC. However, a comprehensive understanding of specific circRNAs involved in both IBD and CRC, and their functional roles is lacking. Here, it is found that circHIPK2 (hsa_circRNA_104507) is a bona fide circRNA consistently upregulated in both IBD and CRC suggesting its potential as a biomarker. Furthermore, silencing of circHIPK2 suppressed the growth of CRC cells in vitro and in vivo. Interestingly, decreased circHipk2 potentiated dextran sulfate sodium (DSS)-induced colitis but alleviated colitis-associated tumorigenesis. Most significantly, mechanistic investigations further unveil that circHIPK2, mediated by FUS, interacting with EIF4A3 to promote the translation of TAZ, ultimately increasing the transcription of downstream target genes CCN1 and CCN2. Taken together, circHIPK2 emerges as a key player in the shared mechanisms of IBD and CRC, modulating the Hippo signaling pathway. CircHIPK2-EIF4A3 axis contributes to cell growth in intestinal epithelial of colitis and CRC by enhancing TAZ translation.

Single-Use, Metabolite Absorbing, Resonant Transducer (SMART) Culture Vessels for Label-Free, Continuous Cell Culture Progression Monitoring.

Secreted metabolites are an important class of bio-process analytical technology (PAT) targets that can correlate to cell conditions. However, current strategies for measuring metabolites are limited to discrete measurements, resulting in limited understanding and ability for feedback control strategies. Herein, a continuous metabolite monitoring strategy is demonstrated using a single-use metabolite absorbing resonant transducer (SMART) to correlate with cell growth. Polyacrylate is shown to absorb secreted metabolites from living cells containing hydroxyl and alkenyl groups such as terpenoids, that act as a plasticizer. Upon softening, the polyacrylate irreversibly conformed into engineered voids above a resonant sensor, changing the local permittivity which is interrogated, contact-free, with a vector network analyzer. Compared to sensing using the intrinsic permittivity of cells, the SMART approach yields a 20-fold improvement in sensitivity. Tracking growth of many cell types such as Chinese hamster ovary, HEK293, K562, HeLa, and E. coli cells as well as perturbations in cell proliferation during drug screening assays are demonstrated. The sensor is benchmarked to show continuous measurement over six days, ability to track different growth conditions, selectivity to transducing active cell growth metabolites against other components found in the media, and feasibility to scale out for high throughput campaigns.

Circ_0012152 Accelerates Acute Myeloid Leukemia Progression through the miR-652-3p/SOX4 Axis.

OBJECTIVE: Acute myeloid leukemia (AML) is an aggressive hematological malignancy characterized by abnormal myeloid blast expansion. Recent studies have demonstrated that circular RNAs play a role in AML pathogenesis. In this study, we aimed to investigate the clinical significance of circ_0012152 in AML and elucidate its underlying molecular mechanism in the pathogenesis of this condition. METHODS: Circ_0012152 expression was detected by quantitative real-time polymerase chain reaction in samples obtained from 247 patients with AML and 40 healthy controls. A systematic analysis of clinical characteristics and prognostic factors was also conducted. Cell growth was assessed using the Cell Counting Kit-8 (CCK-8) assay, and apoptosis and cell cycle progression were evaluated by flow cytometry. Moreover, RNA pull-down was performed to identify target microRNAs, and transcriptome RNA sequencing and bioinformatics analyses were utilized to identify downstream mRNA targets. RESULTS: Circ_0012152 was significantly upregulated in samples from patients with AML and served as an independent adverse prognostic factor for overall survival (OS) (hazard ratio: 2.357; 95% confidence interval 1.258-4.415). The circ_0012152 knockdown reduced cell growth, increased apoptosis, and inhibited cell cycle progression in AML cell lines. RNA pull-down and sequencing identified miR-652-3p as a target microRNA of circ_0012152. Cell growth inhibition by circ_0012152 knockdown was significantly relieved by miR-652-3p inhibitors. We suggested that miR-652-3p targeted SOX4, as the decrease in SOX4 expression resulting from circ_0012152 knockdown was upregulated by miR-652-3p inhibitors in AML cells. CONCLUSION: Circ_0012152 is an independent poor prognostic factor for OS in AML, and it promotes AML cell growth by upregulating SOX4 through miR-652-3p.

Transcription Factor yin-Yang 1 augments nucleoporin 93 oncogene activity and modulates bladder Cancer malignancy.

OBJECTIVE: This study aims to investigate the functional interplay between transcription factor YY1 and nucleoporin 93 (NUP93) in regulating the malignancy of bladder cancer cells. METHODS: NUP93 expressions in bladder cancer tissues and normal counterparts were analyzed using a public dataset and clinical samples. NUP93 and Yin Yang 1 (YY1) mRNA expression and protein levels in T24 and RT4 cells were determined by Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The effect of NUP93 knockdown on the proliferation, migration, and invasion capabilities of cells was evaluated. Concurrently, transcriptional regulation of NUP93 by YY1 was confirmed using a dual luciferase assay. The effect of NUP93 knockdown on tumorigenesis was evaluate in a subcutaneous xenograft mouse model. RESULTS: Elevated levels of NUP93 in bladder cancer tissues and cell lines were observed. Silencing NUP93 significantly suppressed glycolysis, impeded the growth, migration, invasion and tumor formation of bladder cancer cells. The transcription factor YY1 acted as a positive regulator to upregulate NUP93 expression. YY1 overexpression partially rescued the effects of NUP93 silencing on bladder cancer cells. CONCLUSION: Our results uncovered transcription factor YY1 as a positive regulator of NUP93 expression, and NUP93 serves as an oncogenic factor to sustain the malignancy of bladder cancer cells. These findings suggest that targeting the YY1-NUP93 axis could offer novel therapeutic strategies for bladder cancer treatment.

The Influence of N-Acetyl-selenomethionine on Two RONS-Generating Cancer Cell Lines Compared to N-Acetyl-methionine.

N-acetyl-selenomethionine (NASeLM), a representative of the selenium compounds, failed to convince in clinical studies and cell cultures that it neither inhibits cancer growth nor has a chemoprotective effect. This study aims to find out whether NASeLM shows a growth-inhibiting property compared to the carrier substance N-Acetyl-L-methionine (NALM) on two different cancer cells, namely Jurkat cells and MTC-SK cells. METHODS: Jurkat and MTC-SK cells were cultured in the absence or presence of varying concentrations (0-500 µg/mL) of NASeLM and NALM solutions. After 0, 24, 48, and 72 h, mitochondrial activity, cancer cell membrane CP levels, cell growth, and caspase-3 activity were assessed in aliquots of Jurkat and MTC-SK cells. RESULTS: Both substances, NASeLM and NALM, were similarly able to inhibit cell growth and mitochondrial activity of Jurkat cells in a concentration-dependent and time-dependent manner up to 70%. Only the determination of caspase activity showed that only NASeLM was able to increase this to almost 40% compared to the control as well as the same lack of NALM. However, the experiments on MTC-SK cells showed a clear difference in favor of NASeLM compared to NALM. While NASeLM was able to reduce cell growth to up to 55%, the same amount of NALM was only at around 15%, which turned out to be highly significant (p < 0.001). The same could also be measured for the reduction in MTC-SK mitochondrial activity. Time dependence could also be recognized: the longer both substances, NASeLM and NALM, were incubated, the higher the effect on cell growth and mitochondrial activity, in favour of NASeLM. Only NASeLM was able to increase caspase-3 activity in MTC-SK cells: at 250 µg/mL NASeLM, caspase-3 activity increased significantly to 28% after 24 and 48 h compared to the control (14%) or the same NALM concentration (14%). After 72 h, this could still increase to 37%. A further increase in the NASeLM concentration did not result in higher caspase-3 activity. CONCLUSION: NASeLM could clearly increase caspase-3 activity in both cell types, Jurkat or MTC-SK cells, and thus induce cell death. NALM and NASeLM showed a reduction in cell growth and mitochondrial activity in both cell lines: While NALM and NASeLM showed almost identical measurements on Jurkat cells, NASeLM was much more effective on MTC-SK than the non-selenium-containing carrier, indicating that it has additional anti-chemoprotective effects.

Development of functionalized poly(lactide) films with chitosan via SI-SARA ATRP as scaffolds for neuronal cell growth.

Polylactic acid (PLA), a polymer derived from renewable resources, is gaining increasing attention in the development of biomedical devices due to its cost-effectiveness, low immunogenicity, and biodegradability. However, its inherent hydrophobicity remains a problem, leading to poor cell adhesion features. On this basis, the aim of this work was to develop a method for functionalizing the surface of PLA films with a biopolymer, chitosan (CH), which was proved to be a material with intrinsic cell adhesive properties, but whose mechanical properties are insufficient to be used alone. The combination of the two polymers, PLA as a bulk scaffold and CH as a coating, could be a promising combination to develop a scaffold for cell growth. The modification of PLA films involved several steps: aminolysis followed by bromination to graft amino and then bromide groups, poly(glycidyl methacrylate) (PGMA) grafting by surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA ATRP) and finally the CH grafting. To prove the effective adhesive properties, conjugated and non-conjugated films were tested in vitro as substrates for neuronal cell growth using differentiated neurons from human induced pluripotent stem cells. The results demonstrated enhanced cell growth in the presence of CH.

UBA5 inhibition restricts lung adenocarcinoma via blocking macrophage M2 polarization and cisplatin resistance.

UBA5, a ubiquitin-like activated enzyme involved in ufmylation and sumoylation, presents a viable target for pancreatic and breast cancer treatments, yet its role in lung adenocarcinoma (LUAD) remains underexplored. This study reveals UBA5's tumor-promoting effect in LUAD, as evidenced by its upregulation in patients and positive correlation with TNM stages. Elevated UBA5 levels predict poor outcomes for these patients. Pharmacological inhibition of UBA5 using DKM 2-93 significantly curtails the growth of A549, H1299, and cisplatin-resistant A549 (A549/DDP) LUAD cells in vitro. Additionally, UBA5 knockdown via shRNA lentivirus suppresses tumor growth both in vitro and in vivo. High UBA5 expression adversely alters the tumor immune microenvironment, affecting immunostimulators, MHC molecules, chemokines, receptors, and immune cell infiltration. Notably, UBA5 expression correlates positively with M2 macrophage infiltration, the predominant immune cells in LUAD. Co-culture experiments further demonstrate that UBA5 knockdown directly inhibits M2 macrophage polarization and lactate production in LUAD. Moreover, in vivo studies show reduced M2 macrophage infiltration following UBA5 knockdown. UBA5 expression is also associated with increased tumor heterogeneity, including tumor mutational burden, microsatellite instability, neoantigen presence, and homologous recombination deficiency. Experiments indicate that UBA5 overexpression promotes cisplatin resistance in vitro, whereas UBA5 inhibition enhances cisplatin sensitivity in both in vitro and in vivo settings. Overall, these findings suggest that targeting UBA5 inhibits LUAD by impeding cancer cell proliferation, M2 macrophage polarization, and cisplatin resistance.

CYP2E1 deficit mediates cholic acid-induced malignant growth in hepatocellular carcinoma cells.

BACKGROUND: Increased level of serum cholic acid (CA) is often accompanied with decreased CYP2E1 expression in hepatocellular carcinoma (HCC) patients. However, the roles of CA and CYP2E1 in hepatocarcinogenesis have not been elucidated. This study aimed to investigate the roles and the underlying mechanisms of CYP2E1 and CA in HCC cell growth. METHODS: The proteomic analysis of liver tumors from DEN-induced male SD rats with CA administration was used to reveal the changes of protein expression in the CA treated group. The growth of CA-treated HCC cells was examined by colony formation assays. Autophagic flux was assessed with immunofluorescence and confocal microscopy. Western blot analysis was used to examine the expression of CYP2E1, mTOR, AKT, p62, and LC3II/I. A xenograft tumor model in nude mice was used to examine the role of CYP2E1 in CA-induced hepatocellular carcinogenesis. The samples from HCC patients were used to evaluate the clinical value of CYP2E1 expression. RESULTS: CA treatment significantly increased the growth of HCC cells and promoted xenograft tumors accompanied by a decrease of CYP2E1 expression. Further studies revealed that both in vitro and in vivo, upregulated CYP2E1 expression inhibited the growth of HCC cells, blocked autophagic flux, decreased AKT phosphorylation, and increased mTOR phosphorylation. CYP2E1 was involved in CA-activated autophagy through the AKT/mTOR signaling. Finally, decreased CYP2E1 expression was observed in the tumor tissues of HCC patients and its expression level in tumors was negatively correlated with the serum level of total bile acids (TBA) and gamma-glutamyltransferase (GGT). CONCLUSIONS: CYP2E1 downregulation contributes to CA-induced HCC development presumably through autophagy regulation. Thus, CYP2E1 may serve as a potential target for HCC drug development.

Eukaryotic cell size regulation and its implications for cellular function and dysfunction.

Depending on cell type, environmental inputs, and disease, the cells in the human body can have widely different sizes. In recent years, it became clear that cell size is a major regulator of cell function. However, we are only beginning to understand how optimization of cell function determines a given cell's optimal size. Here, we review currently known size control strategies of eukaryotic cells, and the intricate link of cell size to intracellular biomolecular scaling, organelle homeostasis and cell cycle progression. We detail the cell size dependent regulation of early development and the impact of cell size on cell differentiation. Given the importance of cell size for normal cellular physiology, cell size control must account for changing environmental conditions. We describe how cells sense environmental stimuli, such as nutrient availability, and accordingly adapt their size by regulating cell growth and cell cycle progression. Moreover, we discuss the correlation of pathological states with misregulation of cell size, and how for a long time, this was considered a downstream consequence of cellular dysfunction. We review newer studies that reveal a reversed causality, with misregulated cell size leading to pathophysiological phenotypes such as senescence and aging. In summary, we highlight important roles of cell size in cellular function and dysfunction, which could have major implications for both diagnostics and treatment in the clinic.

Extracellular Self-DNA Effects on Yeast Cell Cycle and Transcriptome during Batch Growth.

The cell cycle and the transcriptome dynamics of yeast exposed to extracellular self-DNA during an aerobic batch culture on glucose have been investigated using cytofluorimetric and RNA-seq analyses. In parallel, the same study was conducted on yeast cells growing in the presence of (heterologous) nonself-DNA. The self-DNA treatment determined a reduction in the growth rate and a major elongation of the diauxic lag phase, as well as a significant delay in the achievement of the stationary phase. This was associated with significant changes in the cell cycle dynamics, with slower exit from the G0 phase, followed by an increased level of cell percentage in the S phase, during the cultivation. Comparatively, the exposure to heterologous DNA did not affect the growth curve and the cell cycle dynamics. The transcriptomic analysis showed that self-DNA exposure produced a generalized downregulation of transmembrane transport and an upregulation of genes associated with sulfur compounds and the pentose phosphate pathway. Instead, in the case of the nonself treatment, a clear response to nutrient deprivation was detected. Overall, the presented findings represent further insights into the complex functional mechanisms of self-DNA inhibition.

Alkane-translocated cells of Rhodococcus strains utilize dissolved oxygen in the alkane phase of an aqueous-alkane two-phase culture.

To clarify the growth mechanisms of Rhodococcus in the alkane phase, we measured oxygen utilization in the alkane phase. The results showed that dissolved oxygen decreased significantly when viable cells were present in the alkane phase. The findings suggested that Rhodococcus strains can grow in alkanes and utilize the resident dissolved oxygen.