Rho of Plants patterning: linking mathematical models and molecular diversity.

ROPs (Rho of Plants) are plant specific small GTPases involved in many membrane patterning processes and play important roles in the establishment and communication of cell polarity. These small GTPases can produce a wide variety of patterns, ranging from a single cluster in tip-growing root hairs and pollen tubes to an oriented stripe pattern controlling protoxylem cell wall deposition. For an understanding of what controls these various patterns, models are indispensable. Consequently, many modelling studies on small GTPase patterning exist, often focusing on yeast or animal cells. Multiple patterns occurring in plants, however, require the stable co-existence of multiple active ROP clusters, which does not occur with the most common yeast/animal models. The possibility of such patterns critically depends on the precise model formulation. Additionally, different small GTPases are usually treated interchangeably in models, even though plants possess two types of ROPs with distinct molecular properties, one of which is unique to plants. Furthermore, the shape and even the type of ROP patterns may be affected by the cortical cytoskeleton, and cortex composition and anisotropy differ dramatically between plants and animals. Here, we review insights into ROP patterning from modelling efforts across kingdoms, as well as some outstanding questions arising from these models and recent experimental findings.

Planning and financing of RMNCH+A under National Health Mission: A case study of the Gurugram District of Haryana State.

BACKGROUND: The Health Planning Process under National Health Mission (NHM) is participatory in nature and the State Programme Implementation Plan (PIP) is an aggregation of District PIPs which is examined and approved by the National Programme Coordination Committee (NPCC), Ministry of Health and Family Welfare, Government of India. Many times there are delays in releasing of Record of Proceedings (ROPs)/approvals. This affects utilisation of NHM funds at district level and below and desired outcomes are not achieved. The present study aims to analyse the process of fund flow, disbursement and utilisation of funds on various components under Reproductive Maternal New born Child and Adolescent Health (RMNCH+A) in the district Gurugram. METHODOLOGY: The study was conducted in the District Gurugram of Haryana State, India. One Community Health Centres (CHCs), two Primary Health Centres (PHCs) and four Sub Health Centres were randomly selected. Primary and secondary data were collected in the study. Medical Officer (I/C), Accounts Staff and Health Workers were interviewed using separate schedules regarding process of disbursement, delays in release and utilisation of funds. Separate checklists were prepared to collect data on availability and utilisation of funds at District, CHC and PHC levels under different components of programme. FINDINGS: Study found that PIP is prepared with inputs from Block level but community participation at (PHC) and below was not present. There was a delay in reaching funds to district due to delayed release of ROPs. Almost 30%-40% of the budget could not be utilised due to delay in receiving of budget. Utilisation of funds was less in some programme activities due to vacant positions project staff. Only 38% and 31% of the funds were utilised under the child health and family planning budget head for the district of Gurugram in the year 2016-17. Accounts staffs were overburdened which affected monitoring of funds utilisation. Budget release from State to District and below was through e-Banking. Auxiliary Nurse Midwives (ANMs) at Sub centre used to get Untied Funds at the end of third quarter. The Government introduced new 18 broad budget heads in NHM Budget for improving utilisation of budget. CONCLUSION: Delayed release of ROPs and erroneous estimation of budget under the programme, very rigid and large number of budget heads poses challenges of understanding and analysing expenditure and affects utilisation of funds under the NHM. Moreover, vacant positions in the programme, unrealistic planning, weak community participation in planning of expenditure and unexplained budget cut in ROPs were main challenges faced by the District.

Investigation of ROP GTPase Activity and Cytoskeleton Dynamics During Tip Growth in Root Hairs and Pollen Tubes.

Pollen tubes and root hairs are typical tip-growing cells and are employed as model systems to study plant cell polarity. Previous studies have shown that the Rho family ROP GTPase plays a critical role in the regulation of pollen tube and root hair growth. Periodically, activated ROP GTPase coordinates with the tip-focused calcium gradient, to regulate actin dynamics and vesicle trafficking. Moreover, microtubules are also involved in organelle movement and growth directionality. Here, we describe methods for analyzing the spatiotemporal localization and activity of ROP, cortical microtubule organization, and F-actin dynamics in pollen tubes and/or root hairs.

Functional Characterization of Tomato ShROP7 in Regulating Resistance against Oidium neolycopersici.

ROPs (Rho-like GTPases from plants) are a unique family of small GTP-binding proteins in plants and play vital roles in numerous cellular processes, including growth and development, abiotic stress signaling, and plant defense. In the case of the latter, the role of ROPs as response regulators to obligate parasitism remains largely enigmatic. Herein, we isolated and identified ShROP7 and show that it plays a critical role in plant immune response to pathogen infection. Real-time quantitative PCR analysis revealed that the expression of ShROP7 was significantly increased during incompatible interactions. To establish its requirement for resistance, we demonstrate that virus-induced gene silencing (VIGS) of ShROP7 resulted in increased susceptibility of tomato to Oidium neolycopersici (On) Lanzhou strain (On-Lz). Downstream resistance signaling through H2O2 and the induction of the hypersensitive response (HR) in ShROP7-silenced plants were significantly reduced after inoculating with On-Lz. Taken together, with the identification of ShROP7-interacting candidates, including ShSOBIR1, we demonstrate that ShROP7 plays a positive regulatory role in tomato powdery mildew resistance.

Machinery Safety and Ergonomics: A Case Study Research to Augment Agricultural Tracklaying Tractors' Safety and Usability.

Occupational Health and Safety (OHS) in agricultural activities is an issue of major concern worldwide notwithstanding the ever stricter regulations issued in this sector. In particular, most accidents are related to the use of tractors and the main causes of this phenomenon are due to the lack of rollover protective structures (ROPSs). This happens especially when tractors are used in particular in-field operations that are characterized by limited clearances between tractor and crop rows so that farmers usually use tractors without ROPS (e.g., dismounting it). To solve such a problem, foldable protective structures (FROPSs) have been proposed, which should augment the operator's protection. However, FROPS's conventional solutions underestimate the operators' risk-taking behavior and the widespread misuse of FROPS due to the efforts needed to operate it. The current study aims at contributing to the improvement of the latter issue proposing the development of a novel approach for the implementation of partial assistance systems (PASs) that can reduce the physical effort of the operator when raising/lowering the FROPS. The proposed methodology, which is based on a reverse engineering approach, was verified by means of a practical case study on a tracklaying tractor. Results achieved can contribute to expanding knowledge on technical solutions aimed at improving the human-machinery interaction in the agricultural sector.

Energy Absorption in Actual Tractor Rollovers with Different Tire Configurations.

In order to better understand the complexities of modern tractor rollover, this paper investigates the energy absorbed by a Roll-Over Protective Structure (ROPS) cab during controlled lateral rollover testing carried out on a modern narrow-track tractor with a silent-block suspended ROPS cab. To investigate how different tractor set-ups may influence ROPS and energy partitioning, tests were conducted with two different wheel configurations, wide (equivalent to normal 'open field' operation) and narrow (equivalent to 'orchard/vineyard' operation), and refer to both the width of the tires and the corresponding track. Dynamic load cells and displacement transducers located at the ROPS-ground impact points provided a direct measurement of the energy absorbed by the ROPS cab frame. A trilateration method was developed and mounted onboard to measure load cell trajectory with respect to the cab floor in real-time. The associated video record of each rollover event provided further information and opportunity to explain the acquired data. The narrow tire configuration consistently subjected the ROPS cab frame to more energy than the wide tire arrangement. To better evaluate the influence of the ROPS cab silent-blocks in lateral rollover, static and dynamic tests were performed. The results confirm that tires influence the energy partition significantly and that further understanding of silent-blocks' dynamic performance is warranted.

Efficacy of MLC based cobalt-60 plans: A DVH comparison and analysis with 6 MV plans.

The purpose of this study was to compare 3D treatment plans implemented using 6 MV Linac with a retrofitted multileaf collimator (MLC) based cobalt-60 plans. In this retrospective study, DVH analysis was used to compare homogeneity of dose within the target and the dose received by critical organs. A prototype MLC designed and developed as a retrofit to current cobalt-60 teletherapy machines with a dedicated 3D treatment planning system was used. Cases representing 5 tumor sites like head & neck, glottis, lung, gall bladder, stomach were taken for the study, which were planned using Eclipse treatment planning system and treated with 6 MV photon beams. The plans were re-planned using the retrofit cobalt-60 MLC with same beam arrangement and dose prescription in Radiation Oncology planning system (ROPS). For each case, DVH data was evaluated for both types of beam energies. Conformity index (CI) and homogeneity index (HI) for target were calculated and compared. The conformal plans created using cobalt MLC for five sites were found to be similar to those planned using 6 MV photon beams. CI values close to unity reflected dose uniformity in the target volume while HI evaluated the hotspots in the target volume. It was concluded that plans created using retrofit prototype MLC developed for cobalt-60 teletherapy machines can provide dose distributions comparable to 6 MV photon beams. The prototype MLC developed can provide a promising treatment option for existing telecobalt machines in implementing conformal therapy in developing countries.

Editorial: The Power of Safety Professionals to Effect Change.

In 2006, Cole et al. (2006) reported on tractor overturn-related injuries in Kentucky from a random sample of farmers that numbered 6,063 respondents. The highest number of people who experienced tractor overturns were operators 16 to 20 years old. In 2007, at a National Institute for Occupational Safety and Health (NIOSH) Tractor Safety Initiative meeting in Colorado, John Myers of NIOSH presented a map of the states with the highest overturn fatality rates: Tennessee, Kentucky, West Virginia, Ohio, Pennsylvania, and Illinois. Significantly, four of these states, including Kentucky, overlap the Appalachian region (Cole, 2007; Hard and Myers, 2001). In Kentucky, this region involves farming on slopes, as examined by Saman et al. (2012), who found a high-risk cluster of tractor overturns among ten Kentucky counties in the Appalachian region, with a 97% increased risk of overturn as compared to other Kentucky counties. In 1971, James Arndt of Deere & Company presented a 50-year review of rollover protective structures (ROPS) at a Society of Automotive Engineers (SAE) conference. Arndt (1971) estimated that, over the previous 50 years, 30,000 operators had been killed when crushed by tractor overturns in agriculture and construction work. Since then, ROPS have been recognized as an effective device to prevent death in the event of a tractor overturn (Reynolds and Groves, 2000). Nevertheless, the epidemic of tractor-related deaths has continued into the modern era, and the cost of ROPS has been found to be a significant barrier to retrofitting tractors that lack ROPS (Myers et al., 1998). To provide a low-cost alternative, NIOSH safety engineers have designed, tested, and provided instructions for building and fitting cost-effective ROPS (CROPS) onto pre-ROPS tractors (i.e., tractors built before 1968) (Hard et al., 2016).

Editorial: Response to "ROPS Are Not Homemade".

We are writing in response to the editorial "ROPS Are Not Homemade" by W. E. Field, R. Tormoehlen, S. Ehlers, C. Cheng, A. Talbert, G. Deboy, D. Haberlin, and C. V. Schwab, which was published in the July 2019 issue of the Journal of Agricultural Safety and Health (Field et al., 2019). The editorial warns secondary school teachers and FFA advisors about the potential liability of fabricating and installing low-cost rollover protective structures (ROPS) as service learning projects for agricultural education students. The apparent intent of the editorial is to discourage teachers and advisors from carrying out such projects. We wish to present arguments as to why these are actually highly beneficial projects to undertake, and perhaps one of our best hopes for significantly reducing the number of tractor overturn injuries and fatalities by directly involving our nation's youth.

Genome-wide identification of small G protein ROPs and their potential roles in Solanaceous family.

Small GTPases function as molecular switches to active or inactive signaling cascades via binding or hydrolyzing GTP. A type of plant specific small GTPases, the ROPs are known to be involved in plant growth, development and immunity. We determined whether ROPs are conserved in Solanaceous species and whether they are involved in plant growth, development and resistance against Phytophthora capsisi. In genome-wide screening, a total of 66 ROPs in six Solanaceous species (SolROPs) were identified, including 16 ROPs in Solanum tuberosum L. (potato), 9 in Solanum lycopersicum L. (tomato), 5 in Solanum melongena L. (eggplant), 9 in Capsicum annuum L. (pepper), 13 in Nicotiana benthamiana Domin and 14 in Nicotiana tabacum L. (tobacco). Phylogenetic analysis revealed that 11 AtROPs and 66 SolROPs fall into five distinct clades (I-V) and hence a novel and systematic gene nomenclature was proposed. In addition, a comprehensive expression analysis was performed by making use of an online database. This revealed that ROP genes are differentially expressed during plant growth and development. Moreover, gene expression of SlROP-II.1 in S. lycopersicum could be significantly induced by P. capsici. Subsequently, SlROP-II.1 and its homologues in N. benthamiana and C. annuum (NbROP-II.1 and CaROP-II.1) were selected for functional analysis using virus-induced gene silencing. Infection assays with P. capsici on silenced plants revealed that SlROP-II.1, NbROP-II.1 and CaROP-II.1 play a role in P. capsici resistance, suggesting conserved function of ROP-II clade across different Solanaceous species. In addition, NbROP-II.1 is also involved in regulating plant growth and development. This study signified the diversity of Solanaceous ROPs and their potential roles in plant growth, development and immunity.

Barley ROP-Interactive Partner-a organizes into RAC1- and MICROTUBULE-ASSOCIATED ROP-GTPASE ACTIVATING PROTEIN 1-dependent membrane domains.

BACKGROUND: Small ROP (also called RAC) GTPases are key factors in polar cell development and in interaction with the environment. ROP-Interactive Partner (RIP) proteins are predicted scaffold or ROP-effector proteins, which function downstream of activated GTP-loaded ROP proteins in establishing membrane heterogeneity and cellular organization. Grass ROP proteins function in cell polarity, resistance and susceptibility to fungal pathogens but grass RIP proteins are little understood. RESULTS: We found that the barley (Hordeum vulgare L.) RIPa protein can interact with barley ROPs in yeast. Fluorescent-tagged RIPa, when co-expressed with the constitutively activated ROP protein CA RAC1, accumulates at the cell periphery or plasma membrane. Additionally, RIPa, locates into membrane domains, which are laterally restricted by microtubules when co-expressed with RAC1 and MICROTUBULE-ASSOCIATED ROP-GTPASE ACTIVATING PROTEIN 1. Both structural integrity of MICROTUBULE-ASSOCIATED ROP-GTPASE ACTIVATING PROTEIN 1 and microtubule stability are key to maintenance of RIPa-labeled membrane domains. In this context, RIPa also accumulates at the interface of barley and invading hyphae of the powdery mildew fungus Blumeria graminis f.sp. hordei. CONCLUSIONS: Data suggest that barley RIPa interacts with barley ROPs and specifies RAC1 activity-associated membrane domains with potential signaling capacity. Lateral diffusion of this RAC1 signaling capacity is spatially restricted and the resulting membrane heterogeneity requires intact microtubules and MICROTUBULE-ASSOCIATED ROP-GTPASE ACTIVATING PROTEIN 1. Focal accumulation of RIPa at sites of fungal attack may indicate locally restricted ROP activity at sites of fungal invasion.

Quad Bike Riders' Attitudes toward and Use of Safety Technologies.

Worldwide, the number of quad bike-related injuries and fatalities has increased over the last 30 years and, although quad bike safety has become increasingly important over the last decade, greater understanding of the risks associated with these vehicles is required. This study aimed to improve understanding of the interrelationships between risk perception, risk management, and the use of safety technologies in quad bike operation. A total of 70 quad bike riders were interviewed in two sets of interviews: one targeting riders visiting two forestry fairs, and the other targeting riders with quad bikes equipped with ROPS. The interviews showed that the quad bike riders had a tendency for externalization of risk. This result possibly derives from the articulation and allocation of blame; the majority of respondents saw the problem of quad bike safety as a result of faulty rider behavior, thus shifting focus away from the technology as well as from themselves. This also applies to many of the interviewed ROPS owners, as one of their prime motivators in acquiring ROPS was to improve the safety of others rather than their own safety.

Editorial: ROPS Are Not Homemade.

Safety professionals should speak up when secondary school teachers and FFA advisors consider fabricating and installing low-cost rollover protective structures (ROPS) as service learning projects for ag education students or as a service to the farm community. These projects are often motivated by the desire to address the continued occurrence of tractor rollovers, which are the most frequent cause of farm-related fatalities (NIOSH, 2018). These projects have also been made feasible by the availability of online plans for ROPS fabrication, including plans from the National Institute for Occupational Safety and Health (NIOSH) that are designed for specific makes and models of tractors. Because of the large number of older tractors that were not originally equipped with ROPS, and the cost and lack of easily accessible ROPS retrofits, fabricating a structure to provide operator protection in the event of an overturn can be attractive as a service learning project. In addition, several of the NIOSH Agricultural Injury Prevention Centers have promoted these projects as a means of reducing the frequency of rollover-related injuries. However, in light of the liability risk involved, such projects should be weighed carefully. Fabricating a ROPS is not the same as building a chicken house, fabricating a welding table, or welding together a hay feeder. ROPS are life-saving devices that must meet specific design and installation standards that exceed the expertise available in most secondary school ag education shops, and even most local machine shops. In fact, "ROPS" is a technical term defined by OSHA standards and the Society of Automotive Engineers (SAE). It does not apply-nor should it be applied-to untested, homemade structures that are installed on tractors with the intent of protecting the operator.

Tractor rollover fatalities, analyzing accident scenario.

INTRODUCTION: In many countries, traditional data sources for collecting injuries of workers covered by compulsory accident insurance have recently been integrated by new observatories whose results may differ. A comparative analysis of the Italian data collection systems related to fatal tractor accidents in agriculture was performed focusing on tractor rollover fatalities with the aim of analyzing the accident scenario. METHOD: Data from the Operational Archives of the Italian Workers Compensation Authority (INAIL), which collects injuries of workers covered by compulsory accident insurance and those of the National Surveillance System (INAIL_ASL), which provides narrative text reports of work-related fatal accidents have been analyzed and compared to the information collected by the INAIL Observatory. The INAL Observatory was recently set up to complement the collection of fatal accidents involving agricultural machinery. Italian data were then compared to data available at an international level. Fatal tractor accidents vary considerably with respect to fatal accidents in agriculture, being 10.6 and 43.7% for the Operational Archives and Surveillance System, respectively. National Surveillance System records, implemented with narrative texts allowed the accident scenario to be defined. RESULTS: 71.7% of fatal tractor-related accidents refer to non-ROPS equipped vehicles and of these, 26.5% involved machines originally mounted with a ROPS that had been removed or was inoperative in the folded-down position during the rollover event. Just one fatal event from a collapsed ROPS on the overturned tractor was recorded. It is interesting that 16.6% of fatal accidents involved a clear environmental factor. PRACTICAL APPLICATION: A campaign to train tractor drivers on the correct use of the combination ROPS and seatbelt can contribute to decreasing rollover events with fatal outcomes. Contemporarily a strict requirement to install ROPS and a seatbelt on tractors, combined to an official inspection at the farm level, can increase the chance of survival in a rollover accident.

ROPS designs to protect operators during agricultural tractor rollovers.

Although it is well known that properly used Rollover Protective Structures (ROPS) can virtually prevent agricultural tractor rollover fatalities, the U.S. still has hundreds of these fatalities per year. An estimated 1.6 million tractors are not equipped with ROPS. Many of these tractors do not have ROPS commercially available although they were originally designed to support a ROPS. Some tractors have foldable ROPS that are not used properly. Other ROPS, although meet appropriate performance standards, are not effective at eliminating continuous rolls. To meet this need, a Computer-based ROPS Design Program (CRDP) was developed to quickly generate ROPS designs based on agricultural tractor weights and dimensions. The ROPS designed with the CRDP for the Allis Chalmers 5040 tractor successfully passed the SAE J2194 static longitudinal, transverse, and vertical tests. A simple foldable ROPS lift assist was designed and tested to ease in the raising and lowering of ROPS; decreasing the raising torque from 90 Nm to less than 50 Nm, while also lowering the resisting torque to lower the ROPS. A model to determine the critical ROPS height CRH based on off-road vehicle dimensions and center of gravity (CG) height was developed and evaluated.

Australian Leadership: Saving Lives with Crush Prevention Devices.

The burden of injury and death due to quad bike [all-terrain vehicle, or ATV] use cannot be allowed to continue unchecked, and ongoing delay in action may permit to further avoidable tragedies." -Royal Australasian College of Surgeons (2016, p. 13).

Auxin Signaling in Regulation of Plant Translation Reinitiation.

The mRNA translation machinery directs protein production, and thus cell growth, according to prevailing cellular and environmental conditions. The target of rapamycin (TOR) signaling pathway-a major growth-related pathway-plays a pivotal role in optimizing protein synthesis in mammals, while its deregulation triggers uncontrolled cell proliferation and the development of severe diseases. In plants, several signaling pathways sensitive to environmental changes, hormones, and pathogens have been implicated in post-transcriptional control, and thus far phytohormones have attracted most attention as TOR upstream regulators in plants. Recent data have suggested that the coordinated actions of the phytohormone auxin, Rho-like small GTPases (ROPs) from plants, and TOR signaling contribute to translation regulation of mRNAs that harbor upstream open reading frames (uORFs) within their 5'-untranslated regions (5'-UTRs). This review will summarize recent advances in translational regulation of a specific set of uORF-containing mRNAs that encode regulatory proteins-transcription factors, protein kinases and other cellular controllers-and how their control can impact plant growth and development.

Functional Characterization of Rhoptry Kinome in the Virulent Toxoplasma gondii RH Strain.

Toxoplasma gondii is an obligatory intracellular apicomplexan protozoan which can infect any warm-blooded animal and causes severe diseases in immunocompromised individuals or infants infected in utero. The survival and success of this parasite require that it colonizes the host cell, avoids host immune defenses, replicates within an appropriate niche, and exits the infected host cell to spread to neighboring non-infected cells. All of these processes depend on the parasite ability to synthesis and export secreted proteins. Amongst the secreted proteins, rhoptry organelle proteins (ROPs) are essential for the parasite invasion and host cell manipulation. Even though the functions of most ROPs have been elucidated in the less virulent T. gondii (type II), the roles of ROPs in the highly virulent type I strain remain largely un-characterized. Herein, we investigated the contributions of 15 ROPs (ROP10, ROP11, ROP15, ROP20, ROP23, ROP31, ROP32, ROP33, ROP34, ROP35, ROP36, ROP40, ROP41, ROP46, and ROP47) to the infectivity of the high virulent type I T. gondii (RH strain). Using CRISPR-Cas9, these 15 ROPs genes were successfully disrupted and the effects of gene knockout on the parasite's ability to infect cells in vitro and BALB/c mice in vivo were investigated. These results showed that deletions of these ROPs did not interfere with the parasite ability to grow in cultured human foreskin fibroblast cells and did not significantly alter parasite pathogenicity for BALB/c mice. Although these ROPs did not seem to be essential for the acute infectious stage of type I T. gondii in the mouse model, they might have different functions in other intermediate hosts or play different roles in other life cycle forms of this parasite due to the different expression patterns; this warrants further investigations.

Developing and evaluating a finite element model for predicting the two-posts rollover protective structure nonlinear behaviour using SAE J2194 static test.

This research focuses on applying Non-linear Finite Element (FE) techniques to predict ROPS force-deflection curves under the simulated standardised static tests. The Society of Automotive Engineers (SAE) J2194 ROPS static standard test was selected for this study. According to the SAE J2194 standard, ROPS must be capable of absorbing predefined levels of energy under longitudinal (rear) and transverse (side) load tests before collapsing as well as avoiding large deformations that infringe upon the driver's clearance zone or leave the clearance zone unprotected. A nonlinear finite element approach was used to predict the response of two rear-mount two-post ROPS under simulated side and rear test conditions for Allis Chalmers 5040 and Long 460 tractors. The ROPS were designed with the Computer-based ROPS Design Program using a bolted corner bracket assembly to simplify the ROPS design process. The recommended FE model (ASTM, C3D10M, 0.01) was found to predict the ROPS performance deflection (RPD) with average error less than 10% compared to experimental test measurements. The FE model predicted the ROPS behaviour under rear loads more accurately than under side loads. The developed FE model based on measured stress-strain curves from test specimens was found to predict the ROPS behaviour more accurately than the FE models developed based on the Ramberg-Osgood material model.

The Random Oligonucleotide-Primed Synthesis Assay for the Quantification of DNA Strand Breaks.

DNA strand breaks arise from normal cellular processes such as replication, transcription, and DNA repair as well as spontaneous DNA damage caused by cell metabolic activities. In addition, strand breaks occur due to direct or indirect DNA damage produced by various abiotic and biotic stresses. Strand breaks are among the most problematic DNA lesions because unrepaired strand breaks may lead to cell cycle arrest, gross chromosome rearrangements, or even cell death. Thus, the measurement of the relative number of strand breaks can provide an informative picture of genome stability of a given cell, tissue, or organism. Here, we describe the use of random oligonucleotide-primed synthesis (ROPS) assay for the detection and quantification of the level of strand breaks in tissue samples. The applications of the assay for a quantitative detection of 3'OH, 3'P, or DNA strand breaks at a cleavage site of the deoxyribose residue are discussed.