A change in biophysical properties accompanies heterochromatin formation in mouse embryos.

The majority of our genome is composed of repeated DNA sequences that assemble into heterochromatin, a highly compacted structure that constrains their mutational potential. How heterochromatin forms during development and how its structure is maintained are not fully understood. Here, we show that mouse heterochromatin phase-separates after fertilization, during the earliest stages of mammalian embryogenesis.

Quantitative RNA imaging in single live cells reveals age-dependent asymmetric inheritance.

Asymmetric inheritance of cellular content through cell division plays an important role in cell viability and fitness. The dynamics of RNA segregation are so far largely unaddressed. This is partly due to a lack of approaches to follow RNAs over multiple cellular divisions.

Altered expression response upon repeated gene repression in single yeast cells.

Cells must continuously adjust to changing environments and, thus, have evolved mechanisms allowing them to respond to repeated stimuli. While faster gene induction upon a repeated stimulus is known as reinduction memory, responses to repeated repression have been less studied so far. Here, we studied gene repression across repeated carbon source shifts in over 1,500 single Saccharomyces cerevisiae cells.

Droplet Microfluidic Device for Chemoenzymatic Sensing.

The rapid detection of pollutants in water can be performed with enzymatic probes, the catalytic light-emitting activity of which decreases in the presence of many types of pollutants. Herein, we present a microfluidic system for continuous chemoenzymatic biosensing that generates emulsion droplets containing two enzymes of the bacterial bioluminescent system (luciferase and NAD(P)H:FMN-oxidoreductase) with substrates required for the reaction. The developed chip generates "water-in-oil" emulsion droplets with a volume of 0.

An asymmetric flow-focusing droplet generator promotes rapid mixing of reagents.

Nowadays droplet microfluidics is widely used to perform high throughput assays and for the synthesis of micro- and nanoparticles. These applications usually require packaging several reagents into droplets and their mixing to start a biochemical reaction. For rapid mixing microfluidic devices usually require additional functional elements that make their designs more complex.

Microfluidics for single-cell lineage tracking over time to characterize transmission of phenotypes in .

The budding yeast is an excellent model organism to dissect the maintenance and inheritance of phenotypes due to its asymmetric division. This requires following individual cells over time as they go through divisions to define pedigrees. Here, we provide a detailed protocol for collecting and analyzing time-lapse imaging data of yeast cells.

Alveolar regeneration through a Krt8+ transitional stem cell state that persists in human lung fibrosis.

The cell type specific sequences of transcriptional programs during lung regeneration have remained elusive. Using time-series single cell RNA-seq of the bleomycin lung injury model, we resolved transcriptional dynamics for 28 cell types. Trajectory modeling together with lineage tracing revealed that airway and alveolar stem cells converge on a unique Krt8 + transitional stem cell state during alveolar regeneration.

Cell size sets the diameter of the budding yeast contractile ring.

The formation and maintenance of subcellular structures and organelles with a well-defined size is a key requirement for cell function, yet our understanding of the underlying size control mechanisms is limited. While budding yeast cell polarization and subsequent assembly of a septin ring at the site of bud formation has been successfully used as a model for biological self-assembly processes, the mechanisms that set the size of the septin ring at the bud neck are unknown. Here, we use live-cell imaging and genetic manipulation of cell volume to show that the septin ring diameter increases with cell volume.

Single-Cell Tracing Dissects Regulation of Maintenance and Inheritance of Transcriptional Reinduction Memory.

Transcriptional memory of gene expression enables adaptation to repeated stimuli across many organisms. However, the regulation and heritability of transcriptional memory in single cells and through divisions remains poorly understood. Here, we combined microfluidics with single-cell live imaging to monitor Saccharomyces cerevisiae galactokinase 1 (GAL1) expression over multiple generations.

Disposable luciferase-based microfluidic chip for rapid assay of water pollution.

In the present study, we demonstrate the use of a disposable luciferase-based microfluidic bioassay chip for environmental monitoring and methods for fabrication. The designed microfluidic system includes a chamber with immobilized enzymes of bioluminescent bacteria Photobacterium leiognathi and Vibrio fischeri and their substrates, which dissolve after the introduction of the water sample and thus activate bioluminescent reactions. Limits of detection for copper (II) sulfate, 1,3-dihydroxybenzene and 1,4-benzoquinone for the proposed microfluidic biosensor measured 3 μM, 15 mM, and 2 μM respectively, and these values are higher or close to the level of conventional environmental biosensors based on lyophilized bacteria.

Bimodal rheotactic behavior reflects flagellar beat asymmetry in human sperm cells.

Rheotaxis, the directed response to fluid velocity gradients, has been shown to facilitate stable upstream swimming of mammalian sperm cells along solid surfaces, suggesting a robust physical mechanism for long-distance navigation during fertilization. However, the dynamics by which a human sperm orients itself relative to an ambient flow is poorly understood. Here, we combine microfluidic experiments with mathematical modeling and 3D flagellar beat reconstruction to quantify the response of individual sperm cells in time-varying flow fields.

[The active neuroprotective therapy of acute carotid ischemic stroke of moderate severity].

Objective. To evaluate the efficacy of neuroprotective therapy in carotid ischemic stroke. Material and methods.

[Headache in autonomic-vascular dystonia].

The clinical variants of headaches were observed in 83 patients with autonomic vascular dystonia. The diagnostic table was designed to differentiate between the latter and migraine. Bulbar conjunctiva and retinal microcirculation studies revealed multiple morphological and hemodynamic changes.

[Pathogenetic aspects of ischemic strokes].

The article presents data on total calibrometry of the vascular bed of the brain in 26 patients who had died of ischemic cerebral stroke. All patients with nonthrombotic ischemic cerebral stroke showed a considerable decrease in the total lumen of the cerebrovascular bed on the side of the ischemic focus with a significant increase in the coefficient of hemispherical asymmetry. In most cases impoverishment of the hemodynamics was related not to occlusive or gross stenosing process of one of the major vessels but rather to nonmanifest narrowing of several vessels in the hemisphere on the involved side.

[Clinico-immunologic parallels in atherosclerotic discirculatory encephalopathy].

For disclosing the character of the immunological reactivity disturbances in atherosclerotic discirculatory encephalopathy the humoral and tissue immunity was examined in 160 patients. Signs of an increase of the hypersensitivity (both immediate and delayed) to local antigens were revealed, these signs correlating with the stage of the encephalopathy development. The changes discovered may be of a diagnostic and prognostic value in chronic forms of vascular encephalopathies.

[Disorders in lipoprotein metabolism indices in cerebral atherosclerosis, their importance for diagnosis and medical-occupational expertise].

Using a wide complex of biochemical indices 166 patients with cerebral atherosclerosis were examined. It was shown that in this disease regardless of the period of acute stage a deficiency of the brain circulation of physicochemical changes of the serum proteins, lipoproteins and an oppression of the process of cholesterol exterfication precede quantitative accumulation of total cholesterol in the blood, beta-lipoproteins, a decrease of the lecethin level and changes of protein fractions. Heparin treatment along with improvement of the patients' clinical state, indices of general and brain hemodynamics decreased a free cholesterol level, increased the strength of cholesterol and apoprotein relationship and phosphorolipid content in the blood.

[Cerebral hemodynamics in the acute and remote periods of closed cranio-cerebral trauma].

By using clinical and zonal REG methods the authors examined 204 patients with brain traumas. Such examinations permitted to detect symptoms of a disturbed cerebral vascular tone. In the acute period of a closed brain trauma changes of cerebral hemodynamics were not stable and were nonhomogenous by direction.

[Lipoprotein metabolism disorders in hypertension with a cerebral syndrome and their diagnostic value for medico-occupational expertise].

On the basis of a profound clinico-biochemical study of 182 patients with hypertensive disease the authors established that the development of chronic insufficiency of cerebral circulation in this disorder is accompanied by quantitative and physico-chemical changes in the lipoprotein metabolism. These indices do not change significantly following short sessions of heparinotherpy and comprehensive treatment. Their diagnostical significance for medico-occupational examinations is discussed.