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DNA computation is considered as one fascinating alternative to silicon-based computers, which has evoked substantial attention and gained rapid advancements. Besides realizing versatile functions, implementing spatiotemporal control of logic operations, especially in cellular level, is also of great significance to the development of DNA computation. However, developing simple and efficient methods to restrict DNA logic gates performing in live cells is still a challenge. In this work, we designed a series of DNA logic gates by taking full advantage of the diversity and programmability of G-quadruplex (G4) structure. More importantly, by further utilizing the high affinity and specific endocytosis of cells to aptamer G4, we have achieved in realizing an INHIBIT logic gate whose operational site is precisely restricted in specific live cells. The design strategy may have great potential in the field of molecular computation and smart bio-applications.

Single cell analysis has drawn increasing interest from the research community due to its capability to interrogate cellular heterogeneity, allowing refined tissue classification and facilitating novel biomarker discovery. With the advancement of relevant instruments and techniques, it is now possible to perform multiple omics including genomics, transcriptomics, metabolomics or even proteomics at single cell level. In comparison with other omics studies, single-cell metabolomics (SCM) represents a significant challenge since it involves many types of dynamically changing compounds with a wide range of concentrations. In addition, metabolites cannot be amplified. Although difficult, considerable progress has been made over the past decade in mass spectrometry (MS)-based SCM in terms of processing technologies and biochemical applications. In this review, we will summarize recent progress in the development of promising MS platforms, sample preparation methods and SCM analysis of various cell types (including plant cell, cancer cell, neuron, embryo cell, and yeast cell). Current limitations and future research directions in the field of SCM will also be discussed.

The use of single‐cell RNA sequencing (scRNA‐seq) in microglial research is increasing rapidly. The basic workflow of this approach consists of isolating single cells, followed by sequencing. scRNA‐seq is capable of examining microglial heterogeneity on a cellular level. However, the results gained from applying this technique suffer from discrepancies due to differences between applied methods characteristics such as the number of cells sequenced and the depth of sequencing. This review aims to shed more light on the recent developments that happened in this field and how they are related to the methods used. To do that, we track the progress and limitations of various scRNA‐seq methods currently available. The review then summarizes the current knowledge gained using scRNA‐seq in the field of microglia, including novel subpopulations associated with function and development under homeostasis as well during several pathological conditions such as Alzheimer, lipopolysaccharide response, and HIV in relation to the methods employed. Our review points out that despite major developments found using this technique, current scRNA‐seq methods suffer from high cost, low yields, and nonstandardization of generated data. Additional development of scRNA‐seq methods will raise our awareness of microglia's heterogeneity and plasticity under healthy and pathological conditions., Single‐cell RNA sequencing (scRNA‐seq) reveals that microglia vary by age, brain regions, and by disease. However, scRNA‐seq is still facing challenges the biggest of which is sequencing costs

Nanoparticles are ubiquitous and co-occur with microbial life in every environment on Earth. Interactions between microbes and nanoparticles impact the biogeochemical cycles via accelerating various reaction rates and enabling biological processes at the smallest scales. Distinct from microbe-mineral interactions at large, microbe-nanoparticle interactions may involve higher levels of active recognition and utilization of the reactive, changeable, and thereby 'moldable' nano-sized inorganic phases by microbes, which has been given minimal attention in previous reviews. Here we have compiled the various cases of microbe-nanoparticle interactions with clear and potential benefits to the microbial cells and communities. Specifically, we discussed (i) the high bioavailabilities of nanoparticles due to increased specific surface areas and size-dependent solubility, with a focus on environmentally-relevant iron(III) (oxyhydr)oxides and pyrite, (ii) microbial utilization of nanoparticles as 'nano-tools' for electron transfer, chemotaxis, and storage units, and (iii) speculated benefits of precipitating 'moldable' nanoparticles in extracellular biomineralization. We further discussed emergent questions concerning cellular level responses to nanoparticle-associated cues, and the factors that affect nanoparticles' bioavailabilities beyond size-dependent effects. We end the review by proposing a framework towards more quantitative approaches and by highlighting promising techniques to guide future research in this exciting field.

Summary There are a multitude of resistance strategies that microbes can apply to avoid inhibition by antimicrobials. One of these strategies is the enzymatic modification of the antibiotic, in a process generally termed inactivation. Furthermore, some microorganisms may not be limited to the mere inactivation of the antimicrobial compounds. They can continue by further enzymatic degradation of the compounds' carbon backbone, taking nutritional and energetic advantage of the former antibiotic. This driving force to harness an additional food source in a complex environment adds another level of complexity to the reasonably well‐understood process of antibiotic resistance proliferation on a single cell level: It brings bioprotection into play at the level of microbial community. Despite the possible implications of a resistant community in a host and a lurking antibiotic failure, knowledge of degradation pathways of antibiotics and their connections is scarce. Currently, it is limited to only a few families of antibiotics (e.g. β‐lactams and sulfonamides). In this article, we discuss the fluctuating nature of the relationship between antibiotic resistance and the biodegradation of antibiotics. This distinction mainly depends on the genetic background of the microbe, as general resistance genes can be recruited to function in a biodegradation pathway.

Background Multiple studies have reported adipose tissue reduction after the application of the High‐Intensity Focused Electromagnetic (HIFEM) field technology, yet cellular level evidence of the mechanisms has remained scarce. Objectives This study aims to verify or refute previous single‐study histological evidence and further investigates the proposed mechanism of apoptotic induction. Methods The thigh of two Large White pigs was treated with HIFEM for 30 minutes. Fat punch biopsies were collected from the application area before, immediately after, and 8 hours post‐treatment. Control samples were taken from the abdomen immediately after and 8 hours post‐treatment. Samples were analyzed for pro‐apoptotic DNA markers (BAX, BCL‐2, TXNIP, MMP9, TNF‐α), the levels of free fatty acids (FFA), and the pH levels of the adipose tissue. Results The levels of FFA in the treated adipose tissue increased on average by 127.1% immediately post‐treatment and by 134.1% 8 hours post‐treatment, indicating a rapid breakdown of lipids. The average recorded adipose pH changed from 7.30 ± 0.12 at baseline to 6.60 ± 0.07 immediately post‐treatment (P = .001) and to 7.19 ± 0.12 8 hours post‐treatment. The levels of BAX, TXNIP, MMP9, and TNF‐α increased post‐treatment while BCL‐2 decreased. Control samples showed constant levels of pH and pro‐apoptotic markers. The FFAs in the control samples were increased by 41.6%‐51.4%. Conclusion The changes in the levels of the pro‐apoptotic markers conformed to the previously reported elevated fat apoptosis post‐HIFEM treatments. These effects were accompanied by an increase in FFA levels, and by reduced pH levels, due to the increased acidity in the adipose tissue. Further research is required to explore the potential of nonthermal induction of apoptosis.

Investigating phenotypic heterogeneity can help to better understand and manage microbial communities. However, characterizing phenotypic heterogeneity remains a challenge, as there is no standardized analysis framework. Several optical tools are available, such as flow cytometry and Raman spectroscopy, which describe optical properties of the individual cell. In this work, we compare Raman spectroscopy and flow cytometry to study phenotypic heterogeneity in bacterial populations. The growth stages of three replicate Escherichia coli populations were characterized using both technologies. Our findings show that flow cytometry detects and quantifies shifts in phenotypic heterogeneity at the population level due to its high-throughput nature. Raman spectroscopy, on the other hand, offers a much higher resolution at the single-cell level (i.e., more biochemical information is recorded). Therefore, it can identify distinct phenotypic populations when coupled with analyses tailored toward single-cell data. In addition, it provides information about biomolecules that are present, which can be linked to cell functionality. We propose a computational workflow to distinguish between bacterial phenotypic populations using Raman spectroscopy and validated this approach with an external data set. We recommend using flow cytometry to quantify phenotypic heterogeneity at the population level, and Raman spectroscopy to perform a more in-depth analysis of heterogeneity at the single-cell level. (c) 2019 International Society for Advancement of Cytometry

Alcohol use disorders (AUDs) are very common worldwide and negatively affect both individuals and societies. To understand how normal behavior turns into uncontrollable use of alcohol, several approaches have been utilized in the last decades. However, we still do not completely understand how AUDs evolve or how they are maintained in the brains of affected individuals. In addition, efficient and effective treatment is still in need of development. This review focuses on alternative approaches developed over the last 20 years using Drosophila melanogaster (Drosophila) and Caenorhabditis elegans (C. elegans) as genetic model systems to determine the mechanisms underlying the action of ethanol (EtOH) and behaviors associated with AUDs. All the results and insights of studies over the last 20 years cannot be comprehensively summarized. Thus, a few prominent examples are provided highlighting the principles of the genes and mechanisms that have been uncovered and are involved in the action of EtOH at the cellular level. In addition, examples are provided of the genes and mechanisms that regulate behaviors relevant to acquiring and maintaining excessive alcohol intake, such as decision making, reward and withdrawal, and/or relapse regulation. How the insight gained from the results of Drosophila and C. elegans models can be translated to higher organisms, such as rodents and/or humans, is discussed, as well as whether these insights have any relevance or impact on our understanding of the mechanisms underlying AUDs in humans. Finally, future directions are presented that might facilitate the identification of drugs to treat AUDs.

Spinal cord injury (SCI) may lead to persistent locomotor dysfunction and somatosensory disorders, which adversely affect the quality of life of patients and cause a significant economic burden to the society. The efficacies of current therapeutic interventions are still far from satisfaction as the secondary damages resulting from the complex and progressive molecular alterations after SCI are not properly addressed. Recent studies revealed that long non‐coding RNAs (lncRNAs) are abundant in the brain and might play critical roles in several nervous system disorders. At the cellular level, lncRNAs have been shown to regulate the expression of protein‐coding RNAs and hence participate in neuronal death, demyelination and glia activation. Notably, SCI is characterized by these biological processes, suggesting that lncRNAs could be novel modulators in the pathogenesis of SCI. This review describes recent progresses in the lncRNA transcriptome analyses and their molecular functions in regulating SCI progression.

1 H imaging is concerned with contrast generation among anatomically distinct soft tissues. X-nuclei imaging, on the other hand, aims to reveal the underlying changes in the physiological processes on a cellular level. Advanced clinical MR hardware systems improved 1 H image quality and simultaneously enabled X-nuclei imaging. Adaptation of 1 H methods and optimization of both sequence design and postprocessing protocols launched X-nuclei imaging past feasibility studies and into clinical studies. This review outlines the current state of X-nuclei MRI, with the focus on 23 Na, 35 Cl, 39 K, and 17 O. Currently, various aspects of technical challenges limit the possibilities of clinical X-nuclei MRI applications. To address these challenges, quintessential physical and technical concepts behind different applications are presented, and the advantages and drawbacks are delineated. The working process for methods such as quantification and multiquantum imaging is shown step-by-step. Clinical examples are provided to underline the potential value of X-nuclei imaging in multifaceted areas of application. In conclusion, the scope of the latest technical advance is outlined, and suggestions to overcome the most fundamental hurdles on the way into clinical routine by leveraging the full potential of X-nuclei imaging are presented. Level of Evidence: 1 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:355-376.

Hyperspectral imaging (HSI) techniques play an important role in the food industry for providing rapid, nondestructive, and chemical-free detection method, whereas a microscope can provide detailed information about the microstructure of a food item. As an emerging imaging spectroscopy technique, hyperspectral microscope imaging (HMI) technique combines the advantages of HSI with microscopic imaging and has been gradually applied in the food industry. This review introduces the principles of different kinds of HMI techniques, such as fluorescence HMI, visible/near-infrared HMI, Raman HMI, and infrared HMI. Moreover, detailed applications of HMI techniques are summarized, including evaluation of structures of nutrients, and detection of microorganisms and residues. On the other hand, some challenges and future trends in the applications of these techniques are also discussed. It is concluded that by integrating HSI with microscopy, HMI can not only provide both spectral and spatial information about food substances but also provide their chemical information at the molecular or cellular level. Therefore, HMI techniques have great potentials in nondestructive evaluation of structures of nutrients, and detection of microorganisms and residues for the food industry.

The PtIV prodrug strategy has emerged as an excellent alternative to tackle the problems associated with conventional PtII drug therapy. However, there is a lack of tools to study how this new class of PtIV drugs are processed at the cellular level. Herein, we report the first ratiometric probe for cisplatin detection and use it to investigate PtIV anticancer complexes in biological systems. The probe was able to distinguish between cisplatin and its PtIV derivatives, allowing us to probe the intracellular reduction of PtIV prodrug complexes. The correlation between the amount of active PtII species available after intracellular reduction of PtIV complexes and their cytotoxicity and the role glutathione plays in the reduction of PtIV complexes were investigated.

Polarimetric imaging and image analysis have gained increased interest in soft tissue analysis at the cellular level. However, polarimetric imaging has widely been tested on thin tissue sections to provide reliable information correlated with histopathological findings. Polarimetric bulk tissue analysis always offered an overall assessment of various tissue optical properties for diagnosis. In this study, the histopathological correlation of bulk tissue polarimetry images for soft tissues is discussed. The first-hand information on the use of bulk tissue Mueller polarimetry and image analysis as an alternative to tissue histopathology is presented for surgically extracted colon and breast tissues.

Background Oral squamous cell carcinoma (OSCC) is the most prevalent form of oral cancer. Very few researches have been carried out for the automatic diagnosis of OSCC using artificial intelligence techniques. Though biopsy is the ultimate test for cancer diagnosis, analyzing a biopsy report is a very much challenging task. To develop computer‐assisted software that will diagnose cancerous cells automatically is very important and also a major need of the hour. Aim To identify OSCC based on morphological and textural features of hand‐cropped cell nuclei by traditional machine learning methods. Methods In this study, a structure for semi‐automated detection and classification of oral cancer from microscopic biopsy images of OSCC, using clinically significant and biologically interpretable morphological and textural features, are examined and proposed. Forty biopsy slides were used for the study from which a total of 452 hand‐cropped cell nuclei has been considered for morphological and textural feature extraction and further analysis. After making a comparative analysis of commonly used methods in the segmentation technique, a combined technique is proposed. Our proposed methodology achieves the best segmentation of the nuclei. Henceforth the features extracted were fed into five classifiers, support vector machine, logistic regression, linear discriminant, k‐nearest neighbors and decision tree classifier. Classifiers were also analyzed by training time. Another contribution of the study is a large indigenous cell level dataset of OSCC biopsy images. Results We achieved 99.78% accuracy applying decision tree classifier in classifying OSCC using morphological and textural features. Conclusion It is found that both morphological and textural features play a very important role in OSCC diagnosis. It is hoped that this type of framework will help the clinicians/pathologists in OSCC diagnosis.

Novel optoelectronic instrumentation has been developed for the multispectral imaging of autofluorescence emitted by metabolic fluorophores. The images resolve individual cells while spectra are collected for each pixel in the images. These datacubes are generated at a rate of ten per second – fast enough for surgical guidance. The data is processed in real time to provide a single color-coded image to the surgeon. To date, the system has been applied to fresh, ex-vivo, human surgical specimens and has distinguished breast cancer from benign tissue. The approach is applicable to in-vivo measurements of surgical margins and needle-based optical biopsies. Ongoing work demonstrates that the system has great potential for translation to a hand-held probe with high sensitivity and specificity.

The ability to make decisions at the cellular level is absolutely critical for the survival of organisms. Eukaryotic cells are constantly making binary decisions in response to internal and environmental signals. Among the most notable transducers of information are protein kinases. The regulation of these signaling proteins often relies on the activity of other protein kinases located upstream in the signaling cascade. However, these signaling systems are by their own nature an important source of molecular noise. Herein, we have assessed the role of multisite phosphorylation in detecting signals in the face of molecular noise. To address this issue, we have conceptually envisioned the biochemical transduction machinery as a classifier model that can lead to four possible outputs: true positives and negatives, and false positives and negatives. In this probabilistic framework, we show that multisite phosphorylation represents a mechanism to filter noise during the decision-making process. We present results showing that nonessential phosphorylation sites contribute to increase the rate of true positives while, at the same time, they can lessen the rate of false positives. This simultaneous increase in sensitivity and specificity, makes multisite phosphorylation a valuable and easily implemented mechanism to reliably transduce information in noisy contexts.

The year 2018 marks the 150th anniversary of the first publication of Julius von Sachs' (1832-1897) Lehrbuch der Botanik (Textbook of Botany), which provided a comprehensive summary of what was then known about the plant sciences. Three years earlier, in 1865, Sachs produced the equally impressive Handbuch der Experimental-Physiologie der Pflanzen (Handbook of Experimental Plant Physiology), which summarized the state of knowledge in all aspects of the discipline known today as plant physiology. Both of these books provided numerous insights based on Sachs' seminal experiments. By virtue of a reliance on detailed empirical observation and the rigorous application of chemical and physical principles, it is fair to say that the publication of these two monumental works marked the beginning of what can be called "modern-day" plant science. Moreover, Sachs' Lehrbuch der Botanik prefigured the ascendance of plant molecular biology and the systems biology of photoautotrophic organisms. Regrettably, many of the insights of this great scientist have been forgotten by the generations who followed. It is only fitting, therefore, that the anniversary of the publication of the Lehrbuch der Botanik and the career of "the father of plant physiology" should be honored and reviewed, particularly because Sachs established the physiology of green organisms as an integral branch of botany and incorporated a Darwinian perspective into plant biology. Here we highlight key insights, with particular emphasis on Sachs' detailed discussion of sexual reproduction at the cellular level and his endorsement of Darwinian evolution.

The high-content interrogation of single cells with platforms optimized for the multiparameter characterization of cells in liquid and solid biopsy samples can enable characterization of heterogeneous populations of cells ex vivo. Doing so will advance the diagnosis, prognosis, and treatment of cancer and other diseases. However, it is important to understand the unique issues in resolving heterogeneity and variability at the single cell level before navigating the validation and regulatory requirements in order for these technologies to impact patient care. Since 2013, leading experts representing industry, academia, and government have been brought together as part of the Foundation for the National Institutes of Health (FNIH) Biomarkers Consortium to foster the potential of high-content data integration for clinical translation.

Despite longstanding interest in the evolution and maintenance of discrete phenotypic polymorphisms, the molecular genetic basis of such polymorphism in the wild is largely unknown. Female sex-associated blotched color polymorphisms found in cichlids of Lake Malawi, East Africa represent a highly successful polymorphic phenotype, found and maintained in four genera across the geographic expanse of the lake. Previously, we identified an association with an allelic variant of the paired-box transcription factor gene pax7a and blotched color morphs in Lake Malawi cichlid fishes. Though a diverse range of blotched phenotypes are present in Lake Malawi cichlid species, they all appeared to result from an allele of pax7a that produces increased levels of transcript. Here, we examine the developmental and genetic basis of variation among blotched morphs. First, we confirm that pax7a-associated blotch morphs result primarily from modulation of melanophore development and survival. From lab crosses and natural population studies, we identify at least three alleles of pax7a associated with discrete subtypes of blotched morphs, in addition to the ancestral pax7a allele. Genotypes at pax7a support initial evolution of a novel pax7a allele to produce the blotched class of morphs, followed by subsequent evolution of that pax7a blotched allele to produce additional alleles associated with discrete color morphs. Variant alleles of pax7a produce different levels of pax7a transcript, correlating with pigmentation phenotype at the cellular level. This naturally selected allelic series should serve as a case study for understanding the molecular genetic control of pax7a expression and the evolution of sex-associated alleles. This article is protected by copyright. All rights reserved.

Productivity-poor oligotrophic environments are plentiful on earth. Yet it is not well understood how organisms maintain population sizes under these extreme conditions. Most scenarios consider the adaptation of a single microorganism (isogenic) at the cellular level, which increases their fitness in such an environment. However, in oligotrophic environments, the adaptation of microorganisms at population level - that is, the ability of living cells to differentiate into subtypes with specialized attributes leading to the coexistence of different phenotypes in isogenic populations - remains a little-explored area of microbiology research. In this study, we performed experiments to demonstrate that an isogenic population differentiated to two subpopulations under low energy-flux in chemostats. Fluorescence cytometry and turnover rates revealed that these subpopulations differ in their nucleic acid content and metabolic activity. A mechanistic modelling framework for the dynamic adaptation of microorganisms with the consideration of their ability to switch between different phenotypes was experimentally calibrated and validated. Simulation of hypothetical scenarios suggests that responsive diversification upon a change in energy availability offers a competitive advantage over homogenous adaptation for maintaining viability and metabolic activity with time.

SUMMARY Three-dimensional analyses of the early Ediacaran microfossils from the Weng'an biota (Doushantuo Formation) have focused predominantly on multicellular forms that have been interpreted as embryos, and yet they have defied phylogenetic interpretation principally because of absence of evidence from other stages in their life cycle. It is therefore unfortunate that the affinities of the various other Doushantuo microfossils have been neglected. A new conical fossil that is preserved at a cellular level is described here. The fossil contains distinct cell clusters that are characterized and analysed in three dimensions. These clusters are often exposed at the specimen surface, and the fossil preserves many hemispherical craters that are interpreted as positions where clusters have left the organism. The cell clusters may be either reproductive propagules or infesting organisms. Similar clusters are found in a variety of Doushantuo organisms including putative animal embryos and algae.

The striatum, the largest nucleus of the basal ganglia controlling motor and cognitive functions, can be characterized by a labyrinthine mosaic organization of striosome/matrix compartments. It is unclear how striosome/matrix mosaic formation is spatially and temporally controlled at the cellular level during the striatal development. Here, by combining in vivo electroporation and brain slice cultures, we set up a prospective experimental system where we differentially labeled striosome and matrix cells from the time of birth and followed their distributions and migratory behaviors. Our results showed that, at an initial stage of striosome/matrix mosaic formation, striosome cells were mostly stationary, whereas matrix cells actively migrated in multiple directions irrespective of the presence of striosome cells. The mostly stationary striosome cells were still able to associate to form patchy clusters via attractive interactions. Our results suggested that the restricted migratory capability of striosome cells may only allow them to cluster together when they happen to be located in close proximity to each other and are not separated by actively migrating matrix cells. The way the mutidirectionally migrating matrix cells intermingle with the mostly stationary striosome cells may therefore determine the topographical features of striosomes. At later stages, the actively migrating matrix cells began to repulse the patchy clusters of striosomes, presumably enhancing the striosome cluster formation and the segregation and eventual formation of dichotomous homogeneous striosome/matrix compartments. Taken altogether, our study revealed temporally distinct migratory behaviors of striosome/matrix cells, which may underlie the sequential steps of mosaic formation in the developing striatum. This article is protected by copyright. All rights reserved.

Despite their importance for signalling events, protein-protein interactions cannot easily be analyzed on a single cell level. We developed a robust automated FRET measurement system implemented on a commercial flow cytometer allowing for rapid profiling of molecular associations in living cells. We used this method to measure the most proximal signaling events on human T lymphocyte activation, which preceded calcium influx, and could automatically detect T cell receptor/CD3 complex clustering defects in immunocompromised patients. © 2016 International Society for Advancement of Cytometry.

Herein, we present a highly versatile bioimaging workflow for the multidimensional imaging of biological structures across vastly different length scales. Such an approach allows for the optimised preparation of samples in one go for consecutive X-ray micro-computed tomography, bright-field light microscopy and backscattered scanning electron microscopy, thus, facilitating the disclosure of combined structural information ranging from the gross tissue or cellular level, down to the nanometre scale. In this current study, we characterize various aspects of the hepatic vasculature, ranging from such large vessels as branches of the hepatic portal vein and hepatic artery, down to the smallest sinusoidal capillaries. By employing high-resolution backscattered scanning electron microscopy, we were able to further characterize the subcellular features of a range of hepatic sinusoidal cells including, liver sinusoidal endothelial cells, pit cells and Kupffer cells. Above all, we demonstrate the capabilities of a specimen manipulation workflow that can be applied and adapted to a plethora of functional and structural investigations and experimental models. Such an approach harnesses the fundamental advantages inherent to the various imaging modalities presented herein, and when combined, offers information not currently available by any single imaging platform. J. Cell. Physiol. 232: 249-256, 2017. © 2016 Wiley Periodicals, Inc.

The nonsteroidal anti-inflammatory drugs (NSAIDs) make up a great group of drugs that provide benefits in the prevention of cancers. Coordinated metal ions with NSAIDs provide advantages over the drugs themselves. The metal complexes of NSAIDs display a range of biological activities quite often inaccessible to the original NSAID ligands. NSAIDs-metal complexes have molecular properties different from those of the parent drugs. Thus, if a given NSAIDs-metal complex remains intact in the biological medium its biological target is almost invariably different from the original NSAID target. This review includes results obtained on the antibacterial and antiproliferative activities of metal-NSAIDs complexes and their interaction with intracellular components. The study shows that the molecular weights of metal complexes containing the same NSAID are linearly related to their IC50 values against MCF-7 cells. Moreover, compounds with low molecular weight strongly bind to DNA.

Originally developed to study fundamental aspects of cellular biology, high‐content imaging (HCI) was rapidly adapted to study host–pathogen interactions at the cellular level and adopted as a technology of choice to unravel disease biology. HCI platforms allow for the visualization and quantification of discrete phenotypes that cannot be captured using classical screening approaches. A key advantage of high‐content screening technologies lies in the possibility to develop and interrogate physiologically significant, predictive ex vivo disease models that reproduce complex conditions relevant for infection. Here we review and discuss recent advances in HCI technologies and chemical biology approaches that are contributing to an increased understanding of the intricate host–pathogen interrelationship on the cellular level, and which will foster the development of novel therapeutic approaches for the treatment of human bacterial and protozoan infections. © 2016 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC

Little information regarding viral progeny production (burst size) and host mortality (viral virulence) is currently available for environmentally relevant phages. This is partially due to the difficulty in accurately measuring these infection properties with existing methods. Here, we set up a simple system for determining viral virulence and burst size at the single-cell level following flow cytometric separation of infected cells. We applied this assay to two distinct cyanomyoviruses, Syn9 and S-TIM5, during infection of two marine Synechococcus strains each. We found that virulence ranged from 44%-82%, differing for the same phage on different hosts. Average burst sizes ranged from 21-43 infective viruses/cell, and differed with host for Syn9, whereas the burst size of S-TIM5 was similar for both hosts. In addition, virulence and burst sizes were different for the two phages when infecting their common host. Furthermore, wide-ranging cell-to-cell variability was found for single-cell burst sizes in each of the four interactions, ranging from 2 to over 100 infective viruses/cell. This variability, discerned at both the population and single-cell levels under controlled laboratory conditions, is likely to be much more complex in natural environments.

Surface-enhanced Raman scattering (SERS) has been historically considered a tool for physical scientists. Recently, however, a new avenue has opened for the application of SERS in the medical field, mainly spurred by the implementation of SERS tags. SERS tags are employed for the indirect identification of target molecules, similarly to what fluorescent dyes do, but with several intrinsic advantages. They have proven very useful in in vivo, ex vivo, and in vitro identification of cancerous cells and tissues, with targeting selectivity that can be tuned to recognize individual markers. It has also been demonstrated for the first time that surgical outcomes may be improved via the use of SERS tags, leading to complete tumor resection. Herein, I will explain how SERS tags can aid in the identification of cancerous tissues at the single cell level and how they promise to render SERS a powerful tool for personalized cancer detection.

In this article, a single-cell growth and imaging system was used to study how the growth of single cells of Pseudomonas aeruginosa was affected by temperature shifts. An individual-based modeling was conducted to predict the growth of bacterial single cells. We found that shifts to lower temperatures lengthened the division times of P. aeruginosa single cells, whereas shifts to higher temperature caused a rapid shortening of the division times. The coefficient of variation of the division time decreased as the magnitude of the temperature shifts increased which suggested that the variability of the growth of single P. aeruginosa cells was increased with bigger temperature shifts. Furthermore, the individual-based modeling proposed in this study turned out to be a useful way for predicting the stochastic growth of single bacterial cells under nonconstant temperature conditions. Practical Applications It was deduced that studying the microbial dynamics at the single cell level, which take into account the growth viability and uncertainty of bacterial single cells, could help to establish a more reliable set of microbe-influenced food shelf life and food safety criteria.

The mechanical phenotype of cardiomyocytes is essential to their function as the motor unit of the heart. Traditionally, testing of drugs for cardiotoxic effects has relied on primary cardiomyocytes from animal models and focused on short-term, electrophysiological and arrhythmogenic effects. However, primary cardiomyocytes present challenges arising from their limited viability in culture, and tissue from animal models suffers from a mismatch in their physiology to that of human heart muscle. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) can address these challenges. They also offer the potential to study not only electrophysiological effects but also changes in cardiomyocyte contractile and mechanical function in response to cardiotoxic drugs. With growing recognition of the long-term cardiotoxic effects of some drugs on subcellular structure and function, there is increasing interest in using hiPSC-CMs for in vitro cardiotoxicity studies. In this review, we provide a brief overview of techniques that can be used to quantify changes in the active force cardiomyocytes generate and variations in their inherent stiffness in response to cardiotoxic drugs. We conclude by discussing the application of these tools in understanding how cardiotoxic drugs directly impact the mechanobiology of cardiomyocytes and how cardiomyocytes sense and respond to mechanical load at the cellular level.

Movement requires force transmission to the environment, and motile cells are robustly, though not elegantly, designed nanomachines that often can cope with a variety of environmental conditions by altering the mode of force transmission used(). As with humans, the available modes range from momentary attachment to a substrate when crawling, to shape deformations when swimming, and at the cellular level this involves sensing the mechanical properties of the environment and altering the mode appropriately. While many types of cells can adapt their mode of movement to their microenvironment (ME)(), our understanding of how they detect, transduce and process information from the ME to determine the optimal mode is still rudimentary. The shape and integrity of a cell is determined by its cytoskeleton (CSK), and thus the shape changes that may be required to move involve controlled remodeling of the CSK. Motion in vivo is often in response to extracellular signals, which requires the ability to detect such signals and transduce them into the shape changes and force generation needed for movement. Thus the nanomachine is complex, and while much is known about individual components involved in movement, an integrated understanding of motility in even simple cells such as bacteria is not at hand. In this review we discuss recent advances in our understanding of cell motility and some of the problems remaining to be solved.

An innovative concept for the fabrication of dual-action microrobots capable of performing single-cell microsurgery along with a site-directed drug-delivery feature is presented. These multi-action plant-derived biocompatible "medibots" can play a pivotal role in understanding micromotor interactions at the cellular level, aiming toward the destruction of harmful cells (like cancer) among others in living systems.

It was recently reported that cutting artefacts occur in some species when branches under tension are cut, even under water. We used non-destructive magnetic resonance imaging (MRI) to investigate the change in xylem water distribution at the cellular level in Vitis coignetiae standing stems before and after relaxing tension. Less than 3% of vessels were cavitated when stems under tension were cut under water at a position shorter than the maximum vessel length (MVL) from the MRI point, in three of four plants. The vessel contents remained at their original status, and cutting artefact vessel cavitation declined to

PURPOSE: The goal of the current study was to investigate tissue pathology at the cellular level in traumatic brain injury (TBI) as revealed by Monte Carlo simulation of diffusion tensor imaging (DTI)-derived parameters and elucidate the possible sources of conflicting findings of DTI abnormalities as reported in the TBI literature. METHODS: A model with three compartments separated by permeable membranes was employed to represent the diffusion environment of water molecules in brain white matter. The dynamic diffusion process was simulated with a Monte Carlo method using adjustable parameters of intra-axonal diffusivity, axon separation, glial cell volume fraction, and myelin sheath permeability. The effects of tissue pathology on DTI parameters were investigated by adjusting the parameters of the model corresponding to different stages of brain injury. RESULTS: The results suggest that the model is appropriate and the DTI-derived parameters simulate the predominant cellular pathology after TBI. Our results further indicate that when edema is not prevalent, axial and radial diffusivity have better sensitivity to axonal injury and demyelination than other DTI parameters. CONCLUSION: DTI is a promising biomarker to detect and stage tissue injury after TBI. The observed inconsistencies among previous studies are likely due to scanning at different stages of tissue injury after TBI. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc. Language: en

Individuals affected by the classic chromosome deletion syndromes which were first identified at the beginning of the genetic age, are now positioned to benefit from genomic advances. This issue highlights five of these conditions (4p-, 5p-, 11q-, 18p-, and 18q-). It focuses on the increased in understanding of the molecular underpinnings and envisions how these can be transformed into effective treatments. While it is scientifically exciting to see the phenotypic manifestations of hemizygosity being increasingly understood at the molecular and cellular level, it is even more amazing to consider that we are now on the road to making chromosome abnormalities treatable conditions.

Despite an agreement on most issues surrounding models for how lymphocytes are activated and inactivated, and arising out of the 1970 Two Signal Model of lymphocyte activation, Cohn and I have different perspectives on two critical issues concerning the activation of CD4 T cells. One issue is the origin of the first effector T helper (eTh) cells, postulated by both of us to be required to optimally activate precursor Th (pTh), that is naïve CD4 T cells, to further generate eTh cells. The second issue arises from our agreement that the antigen‐dependent CD4 T cell cooperation, that we both postulate is required to activate naïve CD4 T (pTh) cells, most likely is mediated by the operational recognition of linked epitopes. Although agreeing on the centrality of this operational mechanism, we disagree about how it might be realized at the molecular/cellular level. I respond here to issues raised by Cohn concerning these two mechanistic questions, in his response to my recent article on the activation and inactivation of mature CD4 T cells.

The discovery of the brain's navigation system creates a compelling challenge for neurophysiologists: how do we map the circuitry of a system that can only be definitively identified in awake, behaving animals? Do grid and border cells in the entorhinal cortex correspond to the two classes of principal cell found there, stellate and pyramidal cells? In the hippocampus, does the diversity seen in pyramidal cell subtypes have functional correlates in the place cell system? How do interneurons regulate the activity of spatially tuned principal cells in the hippocampal and entorhinal circuits? Here, we discuss recent literature relating the cellular circuitry of these circuits to in vivo studies of the brain's navigation system, and the role that interneurons have in regulating the activity of principal cells in these circuits. We propose that studying in vitro models of neuronal oscillations in the entorhinal cortex and hippocampus can provide useful insights for bridging the gap in understanding that exists in relating in vivo and behavioral studies to circuit function at the cellular level.

Second-order sensory neurons are dependent on afferents from the sense organs during a critical period in development for their survival and differentiation. Past research has mostly focused on whole populations of neurons, hampering progress in understanding the mechanisms underlying these critical phases. To move toward a better understanding of the molecular and cellular basis of afferent-dependent neuronal development, we developed a new model to study the effects of ear removal on a single identifiable cell in the hindbrain of a frog, the Mauthner cell. Ear extirpation at various stages of Xenopus laevis development defines a critical period of progressively-reduced dependency of Mauthner cell survival/differentiation on the ear afferents. Furthermore, ear removal results in a progressively decreased reduction in the number of dendritic branches. Conversely, addition of an ear results in an increase in the number of dendritic branches. These results suggest that the duration of innervation and the number of inner ear afferents play a quantitative role in Mauthner cell survival/differentiation, including dendritic development. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1339–1351, 2015

The objective of this paper is to compare realistic maximum electromagnetic exposure of human tissues generated by mobile phones with electromagnetic exposures applied during in vitro experiments to assess potentially adverse effects of electromagnetic exposure in the radiofrequency range. We reviewed 80 in vitro studies published between 2002 and present that concern possible adverse effects of exposure to mobile phones operating in the 900 and 1800 MHz bands. We found that the highest exposure level averaged over the cell medium that includes evaluated cells (monolayer or suspension) used in 51 of the 80 studies corresponds to 2 W/kg or less, a level below the limit defined for the general public. That does not take into account any exposure non-uniformity. For comparison, we estimated, by numerical means using dipoles and a commercial mobile phone model, the maximum conservative exposure of superficial tissues from sources operated in the 900 and 1800 MHz bands. The analysis demonstrated that exposure of skin, blood, and muscle tissues may well exceed 40 W/kg at the cell level. Consequently, in vitro studies reporting minimal or no effects in response to maximum exposure of 2 W/kg or less averaged over the cell media, which includes the cells, may be of only limited value for analyzing risk from realistic mobile phone exposure. We, therefore, recommend future in vitro experiments use specific absorption rate levels that reflect maximum exposures and that additional temperature control groups be included to account for sample heating.

Advances in labeling technologies are instrumental to study the developmental mechanisms that control organ formation and function at the cellular level. Until recently, genetic tools relied on the expression of single markers to visualize individual cells or lineages in developing and adult animals. Exploiting the expanding color palette of fluorescent proteins and the power of site-specific recombinases in rearranging DNA fragments, the development of Brainbow strategies in mice made it possible to stochastically label many cells in different colors within the same sample. Over the past years, these pioneering approaches have been adapted for other experimental model organisms, including Drosophila melanogaster, zebrafish, and chicken. Balancing the distinct requirements of single cell and clonal analyses, adjustments were made that both enhance and expand the functionality of these tools. Multicolor cell labeling techniques have been successfully applied in studies analyzing the cellular components of neural circuits and other tissues, and the compositions and interactions of lineages. While being continuously refined, Brainbow technologies have thus found a firm place in the genetic toolboxes of developmental and neurobiologists. For further resources related to this article, please visit the WIREs website.The authors have declared no conflicts of interest for this article.

Introduction We recently developed an animal model to investigate the effects of eccentric contraction (ECC) and blood flow restriction (BFR) on muscle tissue at the cellular level. This study clarified the effects of repeated BFR, ECC, and BFR combined with ECC (BFR+ECC) on muscle fiber hypertrophy. Methods Male Wistar rats were assigned to 3 groups: BFR, ECC, and BFR+ECC. The contralateral leg in the BFR group served as a control (CONT). Muscle fiber cross-sectional area (CSA) of the tibialis anterior was determined after the respective treatments for 6 weeks. Results CSA was greater in the BFR+ECC group than in the CONT (P Cnclusions These results suggest that repeated BFR alone as well as BFR+ECC induces muscle fiber hypertrophy at the cellular level. Muscle Nerve 55: 274-276, 2017.