As bacteria proliferate, DNA replication, chromosome segregation, cell wall synthesis, and cytokinesis occur concomitantly and need to be tightly regulated and coordinated. Although these cell cycle processes have been studied for decades, several mechanisms remain elusive, specifically in coccus-shaped cells such as Staphylococcus aureus. In recent years, major progress has been made in our understanding of how staphylococci divide, including new, fundamental insights into the mechanisms of cell wall synthesis and division site selection. Furthermore, several novel proteins and mechanisms involved in the regulation of replication initiation or progression of the cell cycle have been identified and partially characterized. In this review, we will summarize our current understanding of the cell cycle processes in the spheroid model bacterium S. aureus, with a focus on recent advances in the understanding of how these processes are regulated.

Pollen grains of flowering plants display a fascinating diversity of forms. The observed diversity is determined by the developmental mechanisms involved in the establishment of pollen morphological features. Pollen grains are generally surrounded by an extremely resistant wall displaying apertures that play a key role in reproduction, being the places at which pollen tube growth is initiated. Aperture number, structure, and position (collectively termed \'aperture pattern\') are determined during microsporogenesis, which is the earliest step of pollen ontogeny. Here, we review current knowledge about aperture pattern developmental mechanisms and adaptive significance with respect to plant reproduction and how advances in these fields shed light on our understanding of aperture pattern evolution in angiosperms.

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Coronary angiography allows an accurate assessment of the extent and severity of atherosclerotic coronary narrowing, but it provides little characterization of early detection of potentially asymptomatic vulnerable plaque. The identification of the coronary \"vulnerable patient\" or high-risk plaques remains a major challenge in the treatment of CAD. Recently, growing evidence shows that DNA damage plays a role in the initiation and progression of atherosclerotic plaque. Cytokinesis-block micronucleus (CBMN) assay is one of the most frequently used and validated method for assessing chromosomal damage and genetic instability. Accordingly, the purpose of this systematic review was to retrieve and discuss existing literature on the studies assessing the association between MN and angiographically-proven CAD. A total of 8 studies published between 2001 and 2017 were included in the meta-analysis. Despite a large heterogeneity between studies (I2= 99.7 %, p < 0.0001), an overall increase of MN frequencies was found in patients with CAD compared with control group (meta-MR = 1.96; 95 % CI, 1.5-3.2, p = 0.009). A subgroup analysis showed an increase in the frequency of MN formation for both two- vessel (MR = 2.13, 95 % CI: 0.9-6.9, p = 0.08) and three-vessel disease (MR = 2.89, 95 % CI: 1.84-4.55, P = 0.06). Overall, the results of this meta-analysis provide evidence of an association between CBMN and presence, extent and severity of angiographically-assessed CAD. However, the small number of papers analyzed requires further large and more rigorously designed studies, carefully considering a series of clinical confounding factors, such as the quality of the metabolic control, the influence of drugs and radiation imaging treatments.

The percentage of people affected by overweight, obesity and/or diabetes drastically increased within the last decades. This development is still ongoing, which puts a large part of our society at increased risk for diseases, such as cancer, cardiovascular diseases and cognitive impairment. Especially the development of type 2 diabetes and overweight/obesity could theoretically be prevented. The loss of DNA and genome stability is associated with the above-mentioned metabolic diseases. Insulin resistance, high blood glucose levels or increased body fat are linked to a chronically elevated inflammatory state. This amplifies oxidative stress, might lead to oxidative DNA damage, impairs the cellular proliferation process and results in mutations; all of which increase the possibility for the development of dysfunctional cells, tissue and organs. An established method to measure chromosomal damage is the cytokinesis block micronucleus (CBMN) cytome assay. The aim of this systematic review and meta-analysis is to collect and analyse the current literature of diabetic, obese and overweight patients and their link to cellular mutations measured by the CBMN assay. A clear trend towards increased genome damage in these metabolic diseases was observed. Significantly increased frequencies of chromosomal aberrations were seen in type 2 diabetic subjects (micronuclei frequency: SMD: 1.18, 95% CI: 0.76, 1.60; I2 = 84%). In both, type 1 and type 2 diabetics, disease progression as well as medical quality and quantity were linked to further elevated genome instability. In type 1 diabetic and overweight/obese subjects the number of studies is small and for valid and reliable results more data are needed. Besides the traditionally used material for this method, PBMCs, we extended our analysis to buccal cells in order to qualitatively compare the two cell types. Finally, we discuss knowledge as well as technical/methodical gaps of the CBMN cytome assay and its usability for clinical practice in these metabolic diseases.

Vinyl chloride (VC) is widely used in industry in the production of polyvinyl chloride (PVC), which is used to manufacture a large variety of materials. VC was classified as a known (Group 1) human carcinogen by IARC on the basis of increased risk for liver angiosarcoma and hepatocellular cancer, and the carcinogenicity of VC was shown to be mediated by a genotoxic mechanism. Following inhalation, the compound is rapidly absorbed and metabolized in the liver to the electrophilic metabolites chloroethylene-oxide and chloroacetaldehyde, which form DNA adducts that can be processed into point mutations in cancer-related genes detected in humans and rats exposed to VC. A number of genotoxicity biomarkers were applied in workers exposed to VC to detect early biological responses associated with the carcinogenesis process. The present systematic review analyzed the published studies in which the cytokinesis-block micronucleus assay in peripheral lymphocytes (L-CBMN) was applied in VC-exposed subjects. Thirteen out of fifteen retrieved studies performed in China showed increased MN frequencies (FR 1.92-3.98) associated with increased cumulative exposure or employment time. Twofold and more than threefold increases were detected in PVC-exposed workers exposed to a mean of 50ppm of VC in the former Yugoslavia and in South India, respectively. The meta-analysis of MN frequency from six eligible studies confirmed this tendency (pooled MR 2.32 - 95% CI 1.64-3.27). The benchmark dose lower limit for 10% excess risk (BMDL 10) calculated from three studies resulted in an estimated exposure limit of 0.03-0.07mg/m3. Overall the results of this review showed the need for further studies, especially because PVC products from China may contain high levels of uncoupled VCM that could represent a source of exposure to workers and consumers. Moreover, the results underline the importance of re-evaluating the recommended exposure limits using new biomonitoring methods in addition to MN.

Styrene is a building-block of several compounds used in a wide array of materials and products. The most important human exposure to this substance occurs in industrial settings, especially among reinforced-plastics industry workers. The effect of occupational exposure to styrene on cytogenetics biomarkers has been previously reviewed with positive association observed for chromosomal aberrations, and inconclusive data for the micronucleus assay. Some limitations were noted in those studies, including inadequate exposure assessment and poor epidemiological design. Furthermore, in earlier studies micronuclei frequency was measured with protocols not as reliable as cytokinesis-block micronucleus (CBMN) assay. Aim of the present systematic review and meta-analysis is to investigate genomic instability and DNA damage as measured by the CBMN assay in lymphocytes of subjects exposed to styrene. A total of 11 studies published between 2004 and 2012 were included in the meta-analysis encompassing 479 styrene-exposed workers and 510 controls. The quality of each study was estimated by a quality scoring system which ranked studies according to the consideration of major confounders, exposure characterization, and technical parameters. An overall increase of micronuclei frequencies was found in styrene-exposure workers when compared to referents (meta-MR 1.34; 95% CI 1.18-1.52), with significant increases achieved in six individual studies. The consistency of results in individual studies, the independence of this result from major confounding factors and from the quality of the study strengthens the reliability of risk estimates and supports the use of the CBMN assay in monitoring genetic risk in styrene workers.

The lymphocyte cytokinesis-block micronucleus (CBMN) assay is applied in many different in vivo biomonitoring studies of human exposure to genotoxic chemicals. Among extensively chemicals investigated, we identified petroleum and its derivatives, in particular benzene and the most common mixture of benzene, toluene, and xylene. Although conflicting results have been reported on the effects of benzene exposure, the number of positive findings in independent studies suggests that occupational exposure to benzene causes DNA damage in peripheral blood lymphocytes. To assess current evidence on this hypothesis, we conducted a meta-analysis. Our aim was to evaluate the effect of benzene exposure on genetic damage, quantified using the CBMN assay on individuals occupationally exposed to petroleum and its derivatives. Statistical analyses were conducted using the rmeta package from the free Software Environment for Statistical Computing R. Combined study results indicated that benzene exposure is associated with an increased level of genetic damage in peripheral blood lymphocytes, as reflected by an increased MN frequency. The summary mean difference in MN frequency between exposed and unexposed individuals was 1.64 (95% CI: 0.80-2.47). Overall, this finding points to MN frequency as a sensitive biomarker which could be used to evaluate genetic damage induced by occupational - industrial or environmental - exposure to benzene. This review also identified some important knowledge gaps as well as the need of large, well-designed studies. In particular, it is fundamental to accurately characterize the investigated population, including dietary habits and genetic variability which could modulate MN frequency in both exposed individuals and unexposed controls. In conclusion, according to present findings the use of the CBMN assay in biomonitoring studies could provide objective evidence to guide prioritization of preventive interventions in subjects occupationally exposed to petroleum derivatives, and in particular benzene.

Formaldehyde (FAL) is classified as a Class I carcinogen by the WHO International Agency for Research on Cancer. Therefore, there is a need to validate appropriate methods for detecting its genotoxic effects in vivo in humans. One of the most commonly used methods to measure the genotoxic effects of exposure to environmental chemicals is the lymphocyte cytokinesis-block micronucleus (L-CBMN assay). We performed a systematic review and statistical analysis of the results from all of the published studies in which the L-CBMN assay was used to measure the genotoxic effects of human exposure to FAL. The results of this systematic review indicated that the majority (62%) of the 21 investigations in the 17 published studies we examined showed significant increases in lymphocyte micronucleus (MN) frequency (a biomarker of chromosome breakage or loss), in exposed subjects relative to controls. We used a novel quality score tool to determine if the investigations adequately addressed known variables that affect MN frequency in lymphocytes and found that MN frequency was not explained by quality because there was no significant correlation between quality score and fold-change in MN frequency (R=0.008, P=0.97). The results of all of the studies (positive or negative), when combined together, indicated a highly significant doubling in lymphocyte MN frequency in those exposed to FAL relative to controls (P<0.0001). These observations, together with a significant positive correlation between L-CBMN assay MN frequency and FAL air concentration (R=0.529, P=0.017) indicate the suitability of this method to measure in vivo genotoxicity of FAL. Furthermore, fold-increase in lymphocyte MN frequency in the exposed subjects relative to controls was strongly positively correlated with the duration of FAL exposure (R=0.779, P<0.0001) suggesting the need to better understand the potential for cumulative genomic instability induced by chronic exposures to FAL.

Many studies have reported the occurrence of work-environment contamination by antineoplastic drugs (ANPD), with significant incorporation of trace amounts of these hazardous drugs in hospital personnel. Given the ability of most ANPD to actively bind DNA, thus inducing genotoxic effects, it is of pivotal importance to assess the degree of genotoxic damage (i.e., residual genotoxic risk) in occupationally exposed subjects. The lymphocyte cytokinesis-block micronucleus (L-CBMN) assay is largely used for biological effect monitoring in subjects occupationally exposed to ANPD. In this study, we identified and analyzed the studies published reporting the use of the L-CBMN assay as biomarker of genotoxic risk in health care workers exposed to ANPD with the aim of performing meta-analysis and providing a meta-estimate of the genotoxic effect of exposure. We retrieved 24 studies, published from 1988 to 2015, measuring MN in peripheral blood lymphocytes in health care workers occupationally exposed to ANPD. In 15 out of the 24 studies (62.5%), increased MN frequencies were recognized in exposed subjects as compared to controls. The meta-analysis of MN frequency of the combined studies confirmed an association between occupational exposure to ANPD and cytogenetic effects with an overall meta-estimate of 1.67 [95% CI: 1.41-1.98]. In 16 out of the 24 studies (66.6%) at least one other genotoxicity biomarker, besides L-CBMN assay, was employed for biological effect monitoring. In several studies the effect of exposure to ANPD was evaluated also in terms of MN in exfoliated buccal cells. Other studies focused on genotoxicity endpoints, such as sister chromatid exchanges (3 studies), chromosome aberrations (6 studies), or primary DNA damage investigated by comet assay (7 studies). Overall, there was good agreement between other genotoxicity tests employed and L-CBMN assay outcomes.

The lymphocyte cytokinesis-block micronucleus (CBMN) assay has been applied in hundreds of in vivo biomonitoring studies of humans exposed either environmentally or occupationally to genotoxic chemicals. However, there is an emerging need to re-evaluate the use of MN and other biomarkers within the lymphocyte CBMN cytome assay as quantitative indicators of exposure to main classes of chemical genotoxins. The main aim of the present report is to systematically review published studies investigating the use of the lymphocyte CBMN assay to determine DNA damage in subjects exposed to anaesthetic gases. We also compared performance of the CBMN assay with other DNA damage assays employed and identified strengths and weaknesses of the published studies. We have retrieved 11 studies, published between 1996 and 2013, reporting MN associated with occupational exposures (operating room personnel). The individual job categories were often described (anaesthesiologists, technicians, radiologists) among cases, as well as duration of exposure. All studies reported the compounds present at the workplace and, in some instances, the exposure levels were measured. Controls were usually recruited among personnel at the hospital not exposed to anaesthetics or they were healthy unexposed subjects from general population. The number of investigated subjects, due to the character of the occupation, was relatively smaller than those investigated in other occupational monitoring settings. Overall, the majority of the studies were age- and gender- matched (or investigated only males or females) while less attention was given to lifestyle confounders. Appropriate measurement of exposure, available in approximately half of the studies only, was compromised by the lack of the personal dosimetry-based determinations. In all studies, higher MN frequencies were observed in exposed individuals. The meta-analysis of mean MN frequency of combined studies confirmed this tendency (log mean ratio=0.56 [0.34-0.77]; P=3.51×10-7). Similar differences between the exposed and controls were also observed for other biomarkers.