Three distinct mechanisms, Notch instructive, permissive, and independent, regulate the expression of two different pericardial genes to specify cardiac cell subtypes in Drosophila melanogaster

The development of a complex organ involves the specification and differentiation of diverse cell types. Two major cell types, contractile cardial cells (CCs) and nephrocytic pericardial cells (PCs), comprise the Drosophila heart, with binding sites for Suppressor of Hairless [Su(H)], an integral transcription factor in the Notch signaling pathway, enriched in the enhancers of genes that are specifically expressed in PCs. Here we show three distinct mechanisms regulating the expression of two PC-specific genes, Holes in muscle (Him), and Zn finger homeodomain 1 (zfh1). Him is regulated in a Notch-permissive manner: Su(H) forms a repressor complex with co-repressors that binds to the Him enhancer, repressing transcription in CCs; Notch signaling alleviates this repression in PCs to allow Him transcription. In contrast, zfh1 is transcribed by a Notch-instructive mechanism in most PCs: mere alleviation of repression by preventing the binding of the Su(H) repressor complex to the zfh1 enhancer is not sufficient to activate transcription; zfh1 transcription requires the presence of an activator complex formed by the binding of the Notch intracellular domain to Su(H). A third, Notch-independent pathway activates transcription from the same zfh1 enhancer in the remaining, even skipped-expressing, PCs. Our results illustrate how the same feature, enrichment of Su(H) binding sites in PC-specific gene enhancers, is utilized in two distinct ways to contribute to the same overall goal, the activation of the pericardial gene program, and present an example of a pleiotropic enhancer that is regulated by two independent mechanisms.Panta ManojIndiana State Universit

Economic Loss Caused by Hollow and Shake Defects in Log, Nepal

The management of old growth forest is challenging issues. Thus, the scientific forest management system has been initiating to produce the quality timber to meet the demand of local people and generate the revenue. Especially Shorea robusta is the most valuable timber species but due to hollow and shake defect, timbers are very poor quality. At the same time, old and over mature trees hinders the growth of regeneration and intermediate storey plants. Therefore, this study was objectively carried out to list out the type of hollow and shakes defects in log, assess timber and economic loss due to these defects. The 1A and 2A felling series of block A of Devdah collaborative forest, Ruandehi Nepal was selected as study site. Altogether 215 defected trees measured in both felling series. Next, diameter of two ends and mid-point of log including defected sections and their lengths measured. Formal and informal interview organized with local people including district forest technicians to know causes and types of defects. Volume of defected timber was calculated subtracting net volume from whole volume of log. The economic loss was estimated multiplying defected section of timber with its price. The result showed that shake, canker and hollow are major defects of loss of timber. There two types hollows in logs particularly partial and whole. Meanwhile, the shakes are cup, ring, heart, star and radial. The highest volume loss was 354.34 and 433.7 cubic feet (cft) in Shorea robusta at felling series 1A and 2A respectively. The highest economic loss was US$1557.93 in Shorea robusta caused by degradation to class B from A. Total monetary loss US$ 5804.27 in felling series 1A in Shorea robusta while it was US$ 8365.11 in felling series 2A in same species. This research will be useful for evaluation of forest stand.Keywords: Shake, log, timber, hollow, fellin

Molecular Imaging of Pulmonary Tuberculosis in an Ex-Vivo Mouse Model Using Spectral Photon-Counting Computed Tomography and Micro-CT

Assessment of disease burden and drug efficacy is achieved preclinically using high resolution micro computed tomography (CT). However, micro-CT is not applicable to clinical human imaging due to operating at high dose. In addition, the technology differences between micro-CT and standard clinical CT prevent direct translation of preclinical applications. The current proof-of-concept study presents spectral photon-counting CT as a clinically translatable, molecular imaging tool by assessing contrast uptake in an ex-vivo mouse model of pulmonary tuberculosis (TB). Iodine, a common contrast used in clinical CT imaging, was introduced into a murine model of TB. The excised mouse lungs were imaged using a standard micro-CT subsystem (SuperArgus) and the contrast enhanced TB lesions quantified. The same lungs were imaged using a spectral photoncounting CT system (MARS small-bore scanner). Iodine and soft tissues (water and lipid) were materially separated, and iodine uptake quantified. The volume of the TB infection quantified by spectral CT and micro-CT was found to be 2.96 mm(3) and 2.83 mm(3), respectively. This proof-of-concept study showed that spectral photon-counting CT could be used as a predictive preclinical imaging tool for the purpose of facilitating drug discovery and development. Also, as this imaging modality is available for human trials, all applications are translatable to human imaging. In conclusion, spectral photon-counting CT could accelerate a deeper understanding of infectious lung diseases using targeted pharmaceuticals and intrinsic markers, and ultimately improve the efficacy of therapies by measuring drug delivery and response to treatment in animal models and later in humans

Nature-Based Solutions: Mitigating Flood Effects on Forest Tree Biodiversity and Societal Factors

<p>Nature-based solutions (NBS) effectively address climatic hazards such as floods, droughts, landslides, and broader global sustainable development challenges. However, research on this subject is limited in Nepal. Thus, this study was meticulously designed to evaluate the impact of floods on forest tree biodiversity, social features, and the spatial dynamics of nature-based solutions. The research focused on three community forests—Marka Urra, Kalikhola, and Bhaunijhora in Mahottari districts - where a total of 90 plots were established. Social data collection involved 5 key informant interviews, 3 focus group discussions, and 90 household surveys with photographs and GPS coordinates. The study revealed that while flooding occurrences were frequent, their impact on communities and forest areas reduced significantly following NBS implementation. Notably, the species' evenness and richness for trees and poles remained similar, indicating that floods predominantly affect saplings and seedlings. The study analyzed rainfall patterns from 2009 to 2021, recording the highest rainfall of 2142 mm in 2021 and the lowest of 355.3 mm in 2013. At affected sites, the average Shannon diversity for saplings and seedlings varied, with the highest and lowest values being 0.84±0.07, 0.75±0.10; 1.20±0.08, 0.67±0.09, respectively. Similarly, species evenness and richness showed varying trends among saplings and seedlings. The highest IVI values were recorded for trees, poles, saplings, and seedlings (<i>Shorea robusta</i>) at 218.14, 232.06, 44.26, and 28.16, respectively, while the lowest values were observed for <i>Shorea robusta</i> (212.02, 215.93) and other species like <i>Senegalia catechu, Bidens pilosa, </i>and<i> Elusine indica</i>. The study indicated an increasing trend in the extent and severity of flood events, causing escalating damage to infrastructure, livelihoods, agriculture, forestry, and various sectors. The NBS employed in these community forests included tree plantations, hedges, bamboo fencing, dykes, dams, and gabion walls. This research contributes valuable insights into understanding the effectiveness of nature-based solutions in community forests.</p&gt

Three distinct mechanisms, Notch instructive, permissive, and independent, regulate the expression of two different pericardial genes to specify cardiac cell subtypes.

The development of a complex organ involves the specification and differentiation of diverse cell types constituting that organ. Two major cell subtypes, contractile cardial cells (CCs) and nephrocytic pericardial cells (PCs), comprise the Drosophila heart. Binding sites for Suppressor of Hairless [Su(H)], an integral transcription factor in the Notch signaling pathway, are enriched in the enhancers of PC-specific genes. Here we show three distinct mechanisms regulating the expression of two different PC-specific genes, Holes in muscle (Him), and Zn finger homeodomain 1 (zfh1). Him transcription is activated in PCs in a permissive manner by Notch signaling: in the absence of Notch signaling, Su(H) forms a repressor complex with co-repressors and binds to the Him enhancer, repressing its transcription; upon alleviation of this repression by Notch signaling, Him transcription is activated. In contrast, zfh1 is transcribed by a Notch-instructive mechanism in most PCs, where mere alleviation of repression by preventing the binding of Su(H)-co-repressor complex is not sufficient to activate transcription. Our results suggest that upon activation of Notch signaling, the Notch intracellular domain associates with Su(H) to form an activator complex that binds to the zfh1 enhancer, and that this activator complex is necessary for bringing about zfh1 transcription in these PCs. Finally, a third, Notch-independent mechanism activates zfh1 transcription in the remaining, even skipped-expressing, PCs. Collectively, our data show how the same feature, enrichment of Su(H) binding sites in PC-specific gene enhancers, is utilized by two very distinct mechanisms, one permissive, the other instructive, to contribute to the same overall goal: the specification and differentiation of a cardiac cell subtype by activation of the pericardial gene program. Furthermore, our results demonstrate that the zfh1 enhancer drives expression in two different domains using distinct Notch-instructive and Notch-independent mechanisms

Assessment of metal implant induced artefacts using photon counting spectral CT

The aim is to perform qualitative and quantitative assessment of metal induced artefacts of small titanium biomaterials using photon counting spectral CT. The energy binning feature of some photon counting detectors enables the measured spectrum to be segmented into low, mid and high energy bins in a single exposure. In this study, solid and porous titanium implants submerged in different concentrations of calcium solution were scanned using the small animal MARS photon counting spectral scanner equipped with a polyenergetic X-ray source operated at 118 kVp. Five narrow energy bins (7-45 keV, 45-55 keV, 55-65 keV, 65-75 keV and 75-118 keV) in charge summing mode were utilised. Images were evaluated in the energy domain (spectroscopic images) as well as material domain (material segmentation and quantification). Results show that calcium solution outside titanium implants can be accurately quantified. However, there was an overestimation of calcium within the pores of the scaffold. This information is critical as it can severely limit the assessment of bone ingrowth within metal structures. The energy binning feature of the spectral scanner was exploited and a correction factor, based on calcium concentrations adjacent to and within metal structures, was used to minimise the variation. Qualitative and quantitative evaluation of bone density and morphology with and without titanium screw shows that photon counting spectral CT can assess bone-metal interface with less pronounced artefacts. Quantification of bone growth in and around the implants would help in orthopaedic applications to determine the effectiveness of implant treatment and assessment of fracture healing