In and out of Replication Stress: PCNA/RPA1-Based Dynamics of Fork Stalling and Restart in the Same Cell.

Replication forks encounter various impediments, which induce fork stalling and threaten genome stability, yet the precise dynamics of fork stalling and restart at the single-cell level remain elusive. Herein, we devise a live-cell microscopy-based approach to follow hydroxyurea-induced fork stalling and subsequent restart at 30 s resolution. We measure two distinct processes during fork stalling.

Diffusion of activated ATM explains γH2AX and MDC1 spread beyond the DNA damage site.

During DNA repair, ATM-induced H2AX histone phosphorylation and MDC1 recruitment spread megabases beyond the damage site. While loop extrusion has been suggested to drive this spread, the underlying mechanism remains unclear. Herein, we provide two lines of evidence that loop extrusion is not the only driver of damage-induced γH2AX spread.

Kinetic Landscape of Single Virus-like Particles Highlights the Efficacy of SARS-CoV-2 Internalization.

The efficiency of virus internalization into target cells is a major determinant of infectivity. SARS-CoV-2 internalization occurs via S-protein-mediated cell binding followed either by direct fusion with the plasma membrane or endocytosis and subsequent fusion with the endosomal membrane. Despite the crucial role of virus internalization, the precise kinetics of the processes involved remains elusive.

Dynamics of Replication-Associated Protein Levels through the Cell Cycle.

The measurement of dynamic changes in protein level and localization throughout the cell cycle is of major relevance to studies of cellular processes tightly coordinated with the cycle, such as replication, transcription, DNA repair, and checkpoint control. Currently available methods include biochemical assays of cells in bulk following synchronization, which determine protein levels with poor temporal and no spatial resolution. Taking advantage of genetic engineering and live-cell microscopy, we performed time-lapse imaging of cells expressing fluorescently tagged proteins under the control of their endogenous regulatory elements in order to follow their levels throughout the cell cycle.

The Effect of Dia2 Protein Deficiency on the Cell Cycle, Cell Size, and Recruitment of Ctf4 Protein in .

Cells have evolved elaborate mechanisms to regulate DNA replication machinery and cell cycles in response to DNA damage and replication stress in order to prevent genomic instability and cancer. The E3 ubiquitin ligase SCF in is involved in the DNA replication and DNA damage stress response, but its effect on cell growth is still unclear. Here, we demonstrate that the absence of Dia2 prolongs the cell cycle by extending both S- and G2/M-phases while, at the same time, activating the S-phase checkpoint.

Parapatric genetic divergence among deep evolutionary lineages in the Mediterranean green crab, Carcinus aestuarii (Brachyura, Portunoidea, Carcinidae), accounts for a sharp phylogeographic break in the Eastern Mediterranean.

Background: Recently, population genetic studies of Mediterranean marine species highlighted patterns of genetic divergence and phylogeographic breaks, due to the interplay between impacts of Pleistocene climate shifts and contemporary hydrographical barriers. These factors markedly shaped the distribution of marine organisms and their genetic makeup. The present study is part of an ongoing effort to understand the phylogeography and evolutionary history of the highly dispersive Mediterranean green crab, Carcinus aestuarii (Nardo, 1847), across the Mediterranean Sea.

The subunits of the S-phase checkpoint complex Mrc1/Tof1/Csm3: dynamics and interdependence.

Background: The S-phase checkpoint aims to prevent cells from generation of extensive single-stranded DNA that predisposes to genome instability. The S. cerevisiae complex Tof1/Csm3/Mrc1 acts to restrain the replicative MCM helicase when DNA synthesis is prohibited.

[Hygienic research on new soap preparations for intensive laundry use].

The purpose of the study is to establish hygienic properties of the new preparations for intensive washing and their effect on the skin of man. Examinations are performed on 5 new washing preparations from firm "Verila": "Linda" (from the producer and from the trade network from the country--Ruse, Blagoevgrad, Stara Zagora, Pleven, Cherven Bryag, Plovdiv and Dobrich), recipe No 1, 2, 3 and 4. Sanitary and chemical examinations are carried out: organoleptic indices, nonionogenic surface active substances, total content of surface active substances, content of carbamide, sodium carbonate, ammonium nitrate, formaldehyde and free alkali.

[A hygienic study of new fabrics and models for ordinary work clothing for healthy workers].

Of the basis of literature information for the experience of other countries, data from the Institute of Hygiene and Occupational Health on the hygiene of textile materials and clothes, results from inquiry and additionally performed investigations new work-clothes for health workers are proposed, which have good hygiene and exploitation properties and suitable functioning.

[Health and hygiene research on constructive toys intended for children over 7 under natural conditions].

Physiological and questionnaire investigations are carried out on 10 constructive toys, with the participation of 38 children 7 to 12 years old. A testimonial of the toys is made according to mass, dimensions, technological treatment, packing etc. A number of discrepancies with the hygienic requirements were established: 1) imperfection of the technological treatment (sharp edges, tops and holes, difficult assembling and disassembling of details, not fitting some details at construction, presence of odour, dust in the packings); 2) discrepancy with the announced age destination; 3) faults (incongruity of colours, small dimensions of models and not clear and contrast models, absence of age destination); 4) unphysiological strain and fatigue during play with part of the toys.

[Parental information about the basic causes for dental-jaw deformities].

A total of 610 parents of children from pediatric institutions have been questioned in connection with their information about some of the basic causes of dental-jaw deformities and about their information sources. The results obtained reveal that the parents carefully observe in their children and detect almost always their harmful habits as sucking and oral breathing. What they lack is proper information and motivation to timely cope with those causes as well as to ask for the aid of the stomatologist when necessary.

[Hygienic evaluation of working conditions in furniture factories].

The studies embrace basic productive shops from two furniture enterprises with leading noxious factors of the work environment: toxic chemical substances, noise and vibration (local and general). The concentrations of nine chemical substances from the composition of the used acid-hardening varnishes (polishes) and carbamide-formaldehyde glue are defined. The total concentrations of the formed multicomponent mixtures of organic solvents are calculated.

[Hygienic study and evaluation of textile materials with reduced combustibility with reference to the use of the new anti-inflammable preparations Pyrofix 2 and Torflam].

The new anti-flammable preparations, proposed by the Higher Chemical Technology Institute (Sofia), were studied, namely: Pyrofix 2--for treatment of textile materials and Torflam--for production of anti-inflammable polyester fibres. The following parameters were studied: skin-irritating and skin-sensitizing effect of both preparations, skin toxic effect of Pyrofix 2 and migration of chemicals from the anti-inflammable textile materials (from the composition of the preparations used). The results obtained revealed the absence of skin-irritating and skin-sensitizing effect of both preparations and cumulative dermal toxicity of Pyrofix 2.

[Cleansing of the skin of metabolic products and microorganisms by the wearing of children's outer clothing made of polyacrylonitrile fibers].

The rate of absorption of metabolite products and accumulation of microorganisms on the skin from knitted wear, with different combination of wool /W/ and polyacrylonitrile fibers /PAN/ and of 100% PAN regular production and modified /11 types of products/, is examined in laboratory and natural conditions, as well as bacteriostatic effect related to some important microorganisms. A clearly expressed reverse dependence is established between the absorbing properties of the knitted wear and the metabolite products on the skin and the progressive increase of synthetic PAN fibres in the content. Especially evident is the difference in the quantity of products between the knitted wear of 100% PAN /regular production and modified/ and 100% wool.

[Hygienic evaluation of the content of heavy metals (lead and copper) in cosmetic products].

Heavy metals /lead and copper/ content was studied in various cosmetic articles: creams and cleansing milk, shampoos, hair dyes, eye shadows, rouge, lipsticks, powders, fond de teint, tooth pastes. The method flame atom-absorption spectrometry with chelation and extraction was used for their determination. The subacute dermal toxicity on albino rats was studied with working doses: lead--1,10 and 100 mg/kg, and copper--5,50 and 500 mg/kg.