New role for cardiomyocyte Bmal1 in the regulation of sex-specific heart transcriptomes.

It has been well established that cardiovascular diseases exhibit significant differences between sexes in both preclinical models and humans. In addition, there is growing recognition that disrupted circadian rhythms can contribute to the onset and progression of cardiovascular diseases. However little is known about sex differences between the cardiac circadian clock and circadian transcriptomes in mice. Here, we show that the the core clock genes are expressed in common in both sexes but the circadian transcriptome of the mouse heart is very sex-specific. Hearts from female mice expressed significantly more rhythmically expressed genes (REGs) than male hearts and the temporal pattern of REGs was distinctly different between sexes. We next used a cardiomyocyte-specific knock out of the core clock gene, Bmal1, to investigate its role in sex-specific gene expression in the heart. All sex differences in the circadian transcriptomes were significantly diminished with cardiomyocyte-specific loss of Bmal1. Surprisingly, loss of cardiomyocyte Bmal1 also resulted in a roughly 8-fold reduction in the number of all the differentially expressed genes between male and female hearts. We conclude that cardiomyocyte-specific Bmal1, and potentially the core clock mechanism, is vital in conferring sex-specific gene expression in the adult mouse heart.

Evaluation of the analytical performance of the 15-minute point-of-care DASH™ SARS-CoV-2 RT-qPCR test.

Accurate and timely diagnosis for COVID-19 diagnosis allows highly effective antiviral medications to be prescribed. The DASH™ Rapid PCR System is a sample-to-answer point-of-care platform combining state-of-the-art PCR kinetics with sequence specific hybridization. The platform's first assay, the DASH™ SARS-CoV-2/S test for anterior nares direct swab specimens, received FDA Emergency Use Authorization in March 2022 for point-of-care use. Here we report the analytical characteristics of the assay including limit of detection, dynamic range, and robustness of SARS-CoV-2 variant detection. The limit of detection was determined by testing swabs contrived with one hundred copies of wild type or Omicron BA.5 virus and detecting 20/20 and 19/20, respectively. The dynamic range was assessed with contrived swabs containing 102-106 copies; the log-linear relationship between Cq and copy input was plotted, and the qPCR efficiency calculated from the slope of the line was 101.4%. Detection of seven SARS-CoV-2 variants was demonstrated.

Detecting organelle-specific activity of potassium channels with a DNA nanodevice.

Cell surface potassium ion (K+) channels regulate nutrient transport, cell migration and intercellular communication by controlling K+ permeability and are thought to be active only at the plasma membrane. Although these channels transit the trans-Golgi network, early and recycling endosomes, whether they are active in these organelles is unknown. Here we describe a pH-correctable, ratiometric reporter for K+ called pHlicKer, use it to probe the compartment-specific activity of a prototypical voltage-gated K+ channel, Kv11.1, and show that this cell surface channel is active in organelles. Lumenal K+ in organelles increased in cells expressing wild-type Kv11.1 channels but not after treatment with current blockers. Mutant Kv11.1 channels, with impaired transport function, failed to increase K+ levels in recycling endosomes, an effect rescued by pharmacological correction. By providing a way to map the organelle-specific activity of K+ channels, pHlicKer technology could help identify new organellar K+ channels or channel modulators with nuanced functions.

Mutation-Specific Differences in Kv7.1 (KCNQ1) and Kv11.1 (KCNH2) Channel Dysfunction and Long QT Syndrome Phenotypes.

The electrocardiogram (ECG) empowered clinician scientists to measure the electrical activity of the heart noninvasively to identify arrhythmias and heart disease. Shortly after the standardization of the 12-lead ECG for the diagnosis of heart disease, several families with autosomal recessive (Jervell and Lange-Nielsen Syndrome) and dominant (Romano-Ward Syndrome) forms of long QT syndrome (LQTS) were identified. An abnormally long heart rate-corrected QT-interval was established as a biomarker for the risk of sudden cardiac death. Since then, the International LQTS Registry was established; a phenotypic scoring system to identify LQTS patients was developed; the major genes that associate with typical forms of LQTS were identified; and guidelines for the successful management of patients advanced. In this review, we discuss the molecular and cellular mechanisms for LQTS associated with missense variants in KCNQ1 (LQT1) and KCNH2 (LQT2). We move beyond the "benign" to a "pathogenic" binary classification scheme for different KCNQ1 and KCNH2 missense variants and discuss gene- and mutation-specific differences in K+ channel dysfunction, which can predispose people to distinct clinical phenotypes (e.g., concealed, pleiotropic, severe, etc.). We conclude by discussing the emerging computational structural modeling strategies that will distinguish between dysfunctional subtypes of KCNQ1 and KCNH2 variants, with the goal of realizing a layered precision medicine approach focused on individuals.

The role of the cardiomyocyte circadian clocks in ion channel regulation and cardiac electrophysiology.

Daily variations in cardiac electrophysiology and the incidence for different types of arrhythmias reflect ≈24 h changes in the environment, behaviour and internal circadian rhythms. This article focuses on studies that use animal models to separate the impact that circadian rhythms, as well as changes in the environment and behaviour, have on 24 h rhythms in heart rate and ventricular repolarization. Circadian rhythms are initiated at the cellular level by circadian clocks, transcription-translation feedback loops that cycle with a periodicity of 24 h. Several studies now show that the circadian clock in cardiomyocytes regulates the expression of cardiac ion channels by multiple mechanisms; underlies time-of-day changes in sinoatrial node excitability/intrinsic heart rate; and limits the duration of the ventricular action potential waveform. However, the 24 h rhythms in heart rate and ventricular repolarization are primarily driven by autonomic signalling. A functional role for the cardiomyocyte circadian clock appears to buffer the heart against perturbations. For example, the cardiomyocyte circadian clock limits QT-interval prolongation (especially at slower heart rates), and it may facilitate the realignment of the 24 h rhythm in heart rate to abrupt changes in the light cycle. Additional studies show that modifying rhythmic behaviours (including feeding behaviour) can dramatically impact the 24 h rhythms in heart rate and ventricular repolarization. If these mechanisms are conserved, these studies suggest that targeting endogenous circadian mechanisms in the heart, as well as modifying the timing of certain rhythmic behaviours, could emerge as therapeutic strategies to support heart function against perturbations and regulate 24 h rhythms in cardiac electrophysiology.

Sprout suppression on potato: need to look beyond CIPC for more effective and safer alternatives.

World over, potatoes are being stored at 8-12 °C (85-90 % RH). This is the most common way of long-term (up to 6 to 9 months) storage of potatoes. The benefit of storing the potatoes within the temperature range of 8-12 °C is minimum accumulation of sugars in stored potato tubers. In sub-temperate, sub-tropical and tropical countries of the world, short-term (3 to 4 months) storage of potatoes is being done by non-refrigerated traditional/on-farm methods. These short- and long-term storage methods keep the stored potatoes suitable not only for table purpose but also for processing. However, once the natural dormancy period of potato is over, the prevailing temperatures in these storage methods favour sprouting and sprout growth. Therefore, use of some sprout suppressant to check the sprout growth becomes essential under these methods of potato storage. CIPC [Isopropyl N-(3-chlorophenyl) carbamate] is the most wide spread and commonly used sprout suppressant on potatoes. CIPC has been in use for more than 50 years and research carried out over such a long period use of CIPC has not only enhanced our understanding of its properties and chemistry but also about the production and toxicological status of its metabolites/degradation products. Today, various safety issues and concerns have surfaced primarily due to continuous and long-term use of CIPC. This review presents an appraisal on CIPC and explains the reasons for the long-time dependence on this chemical as a potato sprout suppressant. Issues like maximum residue limit and acceptable daily intake limit are being discussed for CIPC. This article brings an update on practical aspects of potato storage, residue levels of CIPC, efficacy of CIPC as sprout suppressant and health and environmental safety issues linked with CIPC and its metabolites. The aim of this article is to find possible solutions, way outs and future plans that can make the sprout suppression of potatoes safer and more risk free.

Physico-chemical and pasting properties of starch from stored potato tubers.

Starch was separated from tubers of four potato (Solanum tuberosum L.) cultivars, viz. 'Kufri Jyoti', 'Kufri Sindhuri', 'Kufri Chipsona-1' and 'Kufri Chipsona-2' before and after 90 days of storage at 4, 8, 12 and 16°C and, morphological, physico-chemical and pasting properties were studied. Scanning electron microscopy showed oval and irregular shaped starch granules with average diameter of 15 µm, and the granule diameter increased after storage. Peak viscosity was lower after storage at 8°C and higher at 16°C. Hot paste viscosity decreased while breakdown viscosity and set back viscosity increased after storage, and there was no significant change in cold paste viscosity. A significant decrease in pasting time and increase in pasting temperature was observed after storage. Phosphorus content showed significant positive correlation with peak viscosity (r = 0.452, p <0.05) and breakdown viscosity (r = 0.685, p <0.01), and a negative correlation with amylose content (r = -0.674, p <0.01). 'Kufri Sindhuri' starch showed significantly (p <0.05) higher peak, hot paste, breakdown and cold paste viscosity. The X-ray diffraction pattern of starch showed a distinctive maximum peak at around 17°, 2 ϑ and it was not affected by the cultivar or storage temperature.

Glucolipsin A and B, two new glucokinase activators produced by Streptomyces purpurogeniscleroticus and Nocardia vaccinii.

During the screening of the natural products for their ability to increase the activity of glucokinase by relieving inhibition by long chain fatty acyl CoA esters (FAC), two novel compounds, glucolipsin A (1) and B (2) were isolated from the butanol extracts of Streptomyces purpurogeniscleroticus WC71634 and Nocardia vaccinii WC65712, respectively. The structures of these two compounds were established by spectroscopic methods and chemical degradation. Glucolipsin A (1) and B (2) relieved the inhibition of glucokinase by FAC with RC50 values of 5.4 and 4.6 microM.