Circannual rhythms are innately timed long-term (tau ≈ 12 months) cycles of physiology and behavior, crucial for life in habitats ranging from the equator to the Poles. Here the authors propose that circannual rhythm generation depends on tissue-autonomous, reiterated cycles of cell division, functional differentiation, and cell death. They see ...

Circadian (∼24 hour) pacemaking mechanisms exist within single cells. Which cellular properties contrive to produce a precise clockworks, and which cell properties are downstream of it? The literature is conflicted as to whether membrane excitability contributes to the mechanism. Now, a new conditional genetic strategy argues excitability is largely dispensable.

Changes in temperature present the cells of plants with particular challenges. Fortunately, many changes in temperature can be anticipated due to the rhythms of day/night and the seasons. To anticipate changes in the environment most organisms have a circadian clock to optimize daily and seasonal timing of gene expression, metabolism, ...

Abstract Melatonin is an endogenous indolamine classically known as a light/dark regulator. Besides classical functions, melatonin has also showed to have a wide range of antitumoral effects in numerous cancer experimental models. However, no definite mechanism has been described to explain the whole range of antineoplasic effects. Here we describe ...

Circadian oscillation and cell cycle progression are the two most essential rhythmic events present in almost all organisms. Circadian rhythms keep track of time and provide temporal regulation with a period of about 24 h. The cell cycle is optimized for growth and division, but not for time keeping. Circadian gated ...

Ovarian development is related to cell proliferation, differentiation, and apoptosis of granulosa cells and luteal cells under the control of various modulators, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), and growth factors. In the present study, the expression of clock genes and the related regulation mechanism were analyzed in different ...

To determine how the activation of γδ T cells affects the generation of uveitogenic αβ T cells and the development of experimental autoimmune uveitis (EAU). γδ T cells were isolated from B6 mice immunized with the uveitogenic peptide IRBP(1-20) and αβ T cells from immunized TCR-δ(-/-) mice. Resting γδ T ...

In vitro assays have localized circadian pacemakers to individual cells, revealed genetic determinants of rhythm generation, identified molecular players in cell-cell synchronization and determined physiological events regulated by circadian clocks. Although they allow strict control of experimental conditions and reduce the number of variables compared with in vivo studies, they ...

Proteins in tissue obtained from human skin and oral mucosa have shown a significant circadian rhythm, with the peak expression of p27 at 6:00 AM (early G1-phase marker), p53 at 10:50 AM (late G1-phase marker) and cyclin-E at 2:50 PM (S-phase marker). Patients irradiated in late afternoon/evening have shown a ...

T-cell activation via antigen presentation is associated with the formation of a macromolecular membrane assembly termed the immunological synapse (IS). The genesis of the IS and the onset of juxtacrine signalling is characterized by the formation of cell membrane microclusters and the organization of such into segregated microdomains. A central ...

The function of APC/C (anaphase-promoting complex/cyclosome) was initially implicated with the onset of anaphase during mitosis, where its association with Cdc20 targets securin for destruction, thereby allowing the separation of two duplicated daughter genomes. When combined with Cdh1, APC regulates G1/S transition and DNA replication during cell cycle. Beyond cell ...

Progression through mitosis requires the sequential ubiquitination of cell cycle regulators by the anaphase-promoting complex, resulting in their proteasomal degradation. Although several mechanisms contribute to APC/C regulation during mitosis, the APC/C is able to discriminate between its many substrates by exploiting differences in the processivity of ubiquitin chain assembly. Here, ...

During cell proliferation, the abundance of the glycolysis-promoting enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, isoform 3 (PFKFB3), is controlled by the ubiquitin ligase APC/C-Cdh1 via a KEN box. We now demonstrate in synchronized HeLa cells that PFKFB3, which appears in mid-to-late G1, is essential for cell division because its silencing prevents progression into S ...

The conserved anaphase-promoting complex/cyclosome (APC/C) system mediates protein degradation during mitotic progression. Conserved coactivators Cdc20p and Cdh1p regulate the APC/C during early to late mitosis and G(1) phase. Candida albicans is an important fungal pathogen of humans, and it forms highly polarized cells when mitosis is blocked through depletion of ...

Introduction: The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase involved in regulation of the cell cycle through ubiquitination-dependent substrate proteolysis. Many viral proteins have been shown to interact with the APC/C, derailing cell cycle progression in order to facilitate their own replication. Induction of G(2)/M arrest by viral APC/C ...

Antigen-specific cognate interaction of T lymphocytes with antigen-presenting cells (APCs) drives major morphological and functional changes in T cells, including actin rearrangements at the immune synapse (IS) formed at the cell-cell contact area. Here we show, using cell lines as well as primary cells, that clathrin, a protein involved in ...

Toll-like receptor (TLR)9 performs our innate response to bacterial DNA, warning us of the presence of infection. Inhibitory oligodeoxyribonucleotides (INH-ODN) have been developed that selectively block activation of mouse TLR9. Their inhibitory motif consisting of CCx(not-C)(not-C)xxGGG (x = any base) also reduces anti-DNA antibodies in lupus mice. The current study ...

The current paradigm states that exit from mitosis is triggered by the ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C) acting in concert with an activator called CDC20. While this has been well established for a number of systems, the evidence of a critical role of CDC20 in somatic cells is not unequivocal. ...

Circulating tumor cells (CTC) are an important biomarker for several solid cancers. Most of the commercially available systems for enumeration of CTC are based on immunomagnetic enrichment of epithelial cell adhesion molecule (EpCAM/CD326)-expressing CTC before microscopic cell imaging or reverse-transcription PCR (RT-PCR). The aim of this study was to establish ...

By orchestrating the sequential degradation of a large number of cell cycle regulators, the ubiquitin ligase anaphase-promoting complex (APC/C) is essential for proliferation in all eukaryotes. The correct timing of APC/C-dependent substrate degradation, a critical feature of progression through mitosis, was long known to be controlled by mechanisms targeting the ...

The ability of eukaryotes to alter chromatin structure and function is modulated, in part, by histone-modifying enzymes and the post-translational modifications they create. One of these enzymes, PR-Set7/Set8/KMT5a, is the sole histone methyltransferase responsible for the monomethylation of histone H4 lysine 20 (H4K20me1) in higher eukaryotes. Both PR-Set7 and H4K20me1 ...

Biomimetic acryloyloxyethyl phosphorylcholine (APC) was used to react with generation 5 poly(amido amine) (PAMAM) dendrimers (G5) via the Michael addition reaction between primary amino group of PAMAM dendrimers and acrylic functional group of APC. FTIR and (1)H NMR confirmed the success of surface modification of G5. The primary amino and ...

Clonal kidney cells (Vero cells) are extensively utilized in the manufacture of biological preparations for disease diagnostics and therapeutics and also in preparation of vaccines. In all cells, regulation of volume is an essential function coupled to a variety of physiological processes and is a topic of interest. The objective ...

The interaction of living cells with their environment is linked to their adhesive and elastic properties. Even if the mechanics of simple lipid membranes is fairly well understood, the analysis of single cell experiments remains challenging in part because of the mechanosensory response of cells to their environment. To study ...

T-cell recognition of peptide-MHC complexes on APCs requires cell-cell interactions. The molecular events leading to T-cell activation have been extensively investigated, but the underlying physical binding forces between T-cells and APCs are largely unknown. We used single cell force spectroscopy for quantitation of interaction forces between T-cells and APCs presenting ...

Nitrosomonas europaea, a model ammonia oxidizing bacterium, was exposed to a wide variety of aromatic hydrocarbons in 3 h batch assays. The expression of NE1545, a phenol sentinel gene involved in fatty acid metabolism, was monitored via quantitative real-time polymerase chain reaction (qRT-PCR) and a Coulter Counter technique was used ...

Cell volume homeostasis and its fine-tuning to the specific physiological context at any given moment are processes fundamental to normal cell function. The understanding of cell volume regulation owes much to August Krogh, yet has advanced greatly over the last decades. In this review, we outline the historical context of ...

Colorectal cancer metastatic recurrence and chemoresistance are major causes of morbidity and mortality. Colon cancer initiating cells (CCIC) are thought to contribute to both these processes. To identify drugs with anti-CCIC activity we screened a number of FDA approved and investigational compounds. We found that the class I selective histone ...

Two landfill test cells were constructed in a tropical climate using locally available low-cost materials. One cell was operated without a cover on the municipal solid waste to simulate 'open landfill' conditions and the other cell was covered to create 'closed landfill' conditions. Both test cells were monitored over a ...

Alveolar epithelial (AE) surface area is closely correlated with body mass (BM) in mammals. The AE is covered by a surfactant layer produced by alveolar epithelial type II (AE2) cells. We hypothesized that the total number of AE2 cells and the volume of intracellular surfactant-storing lamellar bodies (Lb) are correlated ...

Cell volume is one of the basic characteristics of a cell and is being extensively studied in relationship to a variety of processes, such as proliferation, apoptosis, fertility, or locomotion. At the same time, its measurement under a microscope has not been well developed. The method we propose uses negative ...

The influence of extracellular and intracellular angiotensin II (Ang II) on the cell volume in the failing heart of cardiomyopathic hamsters (TO2) was further investigated as well as the influence of aldosterone and spironolactone on the Ang II action on cell volume. Measurements of cell width and area of quiescent ...

Stomatal movement results in large and repetitive changes in cell volume and consequently surface area. While endocytosis has been extensively studied and is thought to be a major mechanism for accommodating the volume changes as evidenced mainly by fluorescent labelling and confocal imaging, studies at the ultrastructural level in intact ...

The authors have developed a live-cell multimodality microscope combining epifluorescence with digital holographic microscopy; it has been implemented with a decoupling procedure allowing to separately measure from the quantitative phase important cell parameters including absolute volume, shape and integral intracellular refractive index. In combination with the numerous different specific fluorescent ...

The mechanisms that underlie growth plate chondrocyte volume increase and hence bone lengthening are poorly understood. Many cell types activate the Na-K-Cl cotransporter (NKCC) to bring about volume increase. We hypothesised that NKCC may be responsible for the volume expansion of hypertrophic chondrocytes. Metatarsals/metacarpals from 16 rat pups (P(7)) were ...

It is well known that acid/base disturbances modulate proton/bicarbonate transport in the cortical collecting duct. To study the adaptation further we measured the effect of three days of acidosis followed by the rapid recovery from this acidosis on the number and type of intercalated cells in the rabbit cortical collecting ...

Large-conductance, calcium-activated potassium channels (BK) are expressed in principal cells (PC) and intercalated cells (IC) in mammalian nephrons as BK-alpha/beta1 and BK-alpha/beta4, respectively. IC, which protrude into the lumens of tubules, express substantially more BK than PC despite lacking sufficient Na-K-ATPase to support K secretion. We previously showed in mice ...

Malignant gliomas metastasize throughout the brain by infiltrative cell migration into peritumoral areas. Invading cells undergo profound changes in cell shape and volume as they navigate extracellular spaces along blood vessels and white matter tracts. Volume changes are aided by the concerted release of osmotically active ions, most notably K(+) ...

ClC-3, a gene encoding a candidate protein for volume-activated chloride (C(-)) channels, may be involved in tumor development. Herein we report a study using an antisense "knock-down" strategy to investigate the mechanism by which ClC-3 affects cell proliferation in nasopharyngeal carcinoma CNE-2Z cells. With immunoblots and MTT assays we demonstrated ...

Many efforts have been made toward the advancement of capillary electrophoresis chemiluminescence (CE-CL) detection and its applications through continuous development and improvement of interfaces. In this study, a novel rotary cell for CE-CL detection was fabricated and evaluated. A ring-shaped narrow channel with a quartz bottom is made in a ...

Sperm maturation in the epididymis may involve differences between mature and immature spermatozoa in their volume regulatory osmolyte response. Spermatozoa obtained from the rat caput and cauda epididymidis were examined for their ability to regulate volume after transfer from in situ epididymal osmolality (measured to be 343 +/- 13 and ...

The water channel aquaporin 5 (AQP5) seems to play a key role in salivary fluid secretion and appears to be critical in the cell volume regulation of acinar cells. Recently, the cation channel transient potential vanilloid receptor 4 (TRPV4) was shown to be functionally connected to AQP5 and also to ...

BACKGROUND: Ultrasonically induced cell damage and active oxygen generation with a novel porphyrin derivative DCPH-P-Na(I), were compared in the same in vitro insonation setup. MATERIALS AND METHODS: Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound at 2 MHz for up to 60 s in the presence and ...

The influence of cell swelling on cell communication was investigated in cardiomyocytes isolated from the ventricle of adult rats. Measurements of dye coupling were performed in cell pairs using intracellular dialysis of Lucifer Yellow CH. The pipette was attached to one cell of the pair and after a gig ohm ...

Lithium salts have been used as a class of mood stabilizing agents to treat bipolar disorders for over a century. Although lithium is known to affect cell proliferation, apoptosis and migration, the underlying mechanisms have not been well-explored. Emerging evidence indicates that cell volume regulation and volume-activated chloride channels are ...

We have previously demonstrated that exogenous H2O2 stimulates Cl(-)/HCO3(-) exchanger activity in immortalized renal proximal tubular epithelial (PTE) cells from both the Wistar-Kyoto (WKY) rat and the spontaneously hypertensive rat (SHR), this effect being more pronounced in SHR cells. The aim of the present study was to examine the mechanism ...

There is a time-course correlation between nitric oxide (NO)-induced decreases in trabecular meshwork (TM) cell volume and NO-induced increases in outflow facility. The Schlemm's canal (SC) cells may also provide resistance to aqueous humor outflow; therefore, this study tests the involvement of the nitric oxide synthase (NOS) and NO signaling ...

Gastric surface pH (pH(o)) transiently increases in response to focal epithelial damage. The sources of that increase, either from paracellular leakage of interstitial fluid or transcellular acid/base fluxes, have not been determined. Using in vivo microscopy approaches we measured pH(o) with Cl-NERF, tissue permeability with intravenous fluorescent-dextrans to label interstitial ...

Membrane transport changes in human lens epithelial (HLE-B3) cells under hyposmotic and apoptotic stress were compared. Cell potassium content, K(i), uptake of the K congener rubidium, Rb(i), and water content were measured after hyposmotic stress induced by hypotonicity, and apoptotic stress by the protein-kinase inhibitor staurosporine (STP). Cell water increased ...

OBJECTIVE: To explore the functional role of vacuolar H(+)-ATPase in the pH regulation of epididymal fluid and its effect on sperm motility. DESIGN: Experimental study. SETTING: Physiology laboratory in a university. ANIMAL(S): Immature male Sprague-Dawley rats. INTERVENTION(S): The H(+)-ATPase inhibitor was applied to the primary culture of epididymal cells. MAIN ...