Telocytes (TCs), a novel type of mesenchymal or interstitial cell with specific, very long and thin cellular prolongations, have been found in various mammalian organs and have potential biological functions. However, their existence during lung development is poorly understood. This study aimed to investigate the existence, morphological features, and role of CD34+ SCs/TCs in mouse lungs from foetal to postnatal life using primary cell culture, double immunofluorescence, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The immunofluorescence double staining profiles revealed positive expression of CD34 and PDGFR-α, Sca-1 or VEGFR-3, and the expression of these markers differed among the age groups during lung development. Intriguingly, in the E18.5 stage of development, along with the CD34+ SCs/TCs, haematopoietic stem cells and angiogenic factors were also significantly increased in number compared with those in the E14.5, E16.5, P0 and P7. Subsequently, TEM confirmed that CD34+ SCs/TCs consisted of a small cell body with long telopodes (Tps) that projected from the cytoplasm. Tps consisted of alternating thin and thick segments known as podomers and podoms. TCs contain abundant endoplasmic reticulum, mitochondria and secretory vesicles and establish close connections with neighbouring cells. Furthermore, SEM revealed characteristic features, including triangular, oval, spherical, or fusiform cell bodies with extensive cellular prolongations, depending on the number of Tps. Our findings provide evidence for the existence of CD34+ SCs/TCs, which contribute to vasculogenesis, the formation of the air‒blood barrier, tissue organization during lung development and homoeostasis.

BACKGROUND: Mitochondria play a crucial role in adapting to fluctuating energy demands, particularly in various heart diseases. This study investigates mitochondrial morphology near intercalated discs in left ventricular (LV) heart tissues, comparing samples from patients with sinus rhythm (SR), atrial fibrillation (AF), dilated cardiomyopathy (DCM), and ischemic cardiomyopathy (ICM).
METHODS: Transmission electron microscopy was used to analyze mitochondria within 0-3.5 μm and 3.5-7 μm of intercalated discs in 9 SR, 10 AF, 9 DCM, and 8 ICM patient samples. Parameters included mean size in µm2 and elongation, count, percental mitochondrial area in the measuring frame, and a conglomeration score.
RESULTS: AF patients exhibited higher counts of small mitochondria in the LV myocardium, resembling SR. DCM and ICM groups had fewer, larger, and often hydropic mitochondria. Accumulation rates and percental mitochondrial area were similar across groups. Significant positive correlations existed between other defects/size and hydropic mitochondria and between count/area and conglomeration score, while negative correlations between count and size/other defects and between hydropic mitochondria and count could be seen as well.
CONCLUSIONS: Mitochondrial parameters in the LV myocardium of AF patients were similar to those of SR patients, while DCM and ICM displayed distinct changes, including a decrease in number, an increase in size, and compromised mitochondrial morphology. Further research is needed to fully elucidate the pathophysiological role of mitochondrial morphology in different heart diseases, providing deeper insights into potential therapeutic targets and interventions.

In this study, the morphology and ultrastructure of the compound eye of Asi. xanthospilota were examined by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), micro-computed tomography (μCT), and 3D reconstruction. Spectral sensitivity was investigated by electroretinogram (ERG) tests and phototropism experiments. The compound eye of Asi. xanthospilota is of the apposition type, consisting of 611.00 ± 17.53 ommatidia in males and 634.8 0 ± 24.73 ommatidia in females. Each ommatidium is composed of a subplano-convex cornea, an acone consisting of four cone cells, eight retinular cells along with the rhabdom, two primary pigment cells, and about 23 secondary pigment cells. The open type of rhabdom in Asi. xanthospilota consists of six peripheral rhabdomeres contributed by the six peripheral retinular cells (R1~R6) and two distally attached rhabdomeric segments generated solely by R7, while R8 do not contribute to the rhabdom. The orientation of microvilli indicates that Asi. xanthospilota is unlikely to be a polarization-sensitive species. ERG testing showed that both males and females reacted to stimuli from red, yellow, green, blue, and ultraviolet light. Both males and females exhibited strong responses to blue and green light but weak responses to red light. The phototropism experiments showed that both males and females exhibited positive phototaxis to all five lights, with blue light significantly stronger than the others.

The environment surrounding proteins is tightly linked to its dynamics, which can significantly influence the conformation of proteins. This study focused on the effect of pH conditions on the ultrastructure of Immunoglobulin E (IgE) molecules. Herein, the morphology, height, and area of IgE molecules incubated at different pH were imaged by atomic force microscopy (AFM), and the law of IgE changes induced by pH value was explored. The experiment results indicated that the morphology, height and area of IgE molecules are pH dependent and highly sensitive. In particular, IgE molecules were more likely to present small-sized ellipsoids under acidic conditions, while IgE molecules tend to aggregate into large-sized flower-like structures under alkaline conditions. In addition, it was found that the height of IgE first decreased and then increased with the increase of pH, while the area of IgE increased with the increase of pH. This work provides valuable information for further study of IgE, and the methodological approach used in this study is expected to developed into AFM to investigate the changes of IgE molecules mediated by other physical and chemical factors. RESEARCH HIGHLIGHTS: The ultrastructure of IgE molecules is pH dependent and highly sensitive. IgE molecules were tend to present small-sized ellipsoids under acidic pH. Alkaline pH drives IgE self-assembly into flower-like aggregates.

Intracellular biomolecular condensates, which form via phase separation, display a highly organized ultrastructure and complex properties. Recent advances in optical imaging techniques, including super-resolution microscopy and innovative microscopic methods that leverage the intrinsic properties of the molecules observed, have transcended the limitations of conventional microscopies. These advances facilitate the exploration of condensates at finer scales and in greater detail. The deployment of these emerging but sophisticated imaging tools allows for precise observations of the multiphasic organization and physicochemical properties of these condensates, shedding light on their functions in cellular processes. In this review, we highlight recent progress in methodological innovations and their profound implications for understanding the organization and dynamics of intracellular biomolecular condensates.

OBJECTIVE: Interruption of aortic arch (IAA) is a rare congenital heart disease. This study aims to investigate echocardiographic features and pathological ultrastructural characteristics of fetal IAA and to further analyze its pathological evolution.
METHODS: A retrospective analysis was conducted on prenatal echocardiographic, post-surgical, or autopsy findings of fetuses prenatally diagnosed with IAA. Prenatal echocardiographic tracking was used to observe the internal diameters and Z-scores of different segments of the aortic arch and the changes in the narrowed section. These observations were combined with autopsy and pathological findings to explore the potential intrauterine evolution of IAA and its cytological basis.
RESULTS: The study included 34 fetuses with IAA, with 3, 3, and 28 fetuses prenatally diagnosed with aortic arch dysplasia (AAD), coarctation of aorta (CoA), and IAA, respectively. The 3 AAD and 3 CoA fetuses chose termination of pregnancy 1 to 2 weeks after prenatal ultrasound diagnosis, and autopsy confirmed IAA. Among the 28 fetuses prenatally diagnosed with IAA, 6 cases of CoA progressively worsened, eventually evolving into type A IAA as observed through echocardiographic follow-up. The remaining 22 cases were diagnosed as IAA on the first prenatal ultrasound. Postnatal surgery corrected 3 cases, while 27 cases opted for pregnancy termination, and 4 cases resulted in intrauterine death. Echocardiographic features of the fetal IAA included a significantly smaller left ventricle compared with the right or negligible difference on the four-chamber view, a significantly smaller aorta than the pulmonary artery on the three-vessel view, and a lack of connection between the aorta and the descending aorta on the three-vessel-trachea and aortic arch views. The aortic arch appears less curved and more rigid, losing the normal \"V\" shape between the aorta, ductus arteriosus, and descending aorta. Color Doppler ultrasound showed no continuous blood flow signal at the interruption site, with reversed blood flow visible in the ductus arteriosus. Transmission electron microscopy of 7 IAA fetuses revealed numerous disorganized smooth muscle cells between the elastic membranes near the aortic arch interruption site, significantly increased in number compared with the proximal ascending aorta. The elastic membranes were thicker and more twisted near the interruption site. The interruption area lacked normal endothelial cells and lumen, with only remnants of necrotic endothelial cells, disorganized short and thick elastic membranes, and randomly arranged smooth muscle cells.
CONCLUSIONS: Prenatal echocardiography is the primary diagnostic tool for fetal IAA. Post-surgical follow-up and autopsy help identify complications and disease characteristics, enhancing diagnostic accuracy. Some fetal IAA may evolve from AAD or CoA, with potential pathogenesis related to ischemia, hypoxia, and migration of ductal constrictive components.
目的: 主动脉弓离断(interruption of aortic arch，IAA)是一种罕见的先天性心脏疾病。本研究探讨IAA胎儿的超声心动图和病理学超微结构特征，并进一步分析其演变的病理过程。方法: 回顾性分析产前诊断并经手术或尸体解剖确诊的IAA胎儿的产前超声心动图、术后病理检查或尸体解剖结果等资料。采用产前超声心动图追踪观察IAA胎儿主动脉弓各节段内径及Z值，以及狭窄段主动脉弓的变化情况，结合尸体解剖及病理检查结果，探讨胎儿IAA可能的宫内演变过程及其发生的细胞学基础。结果: 纳入34例IAA胎儿，分别有3、3、28例产前超声诊断为主动脉弓发育不良(aortic arch dysplasia，AAD)、主动脉缩窄(coarctation of aorta，CoA)、IAA。3例AAD和3例CoA胎儿均在产前超声检查1~2周后选择引产，并经尸体解剖证实为IAA。28例产前超声诊断为IAA的胎儿中6例为CoA进行性加重，在超声心动图追踪复查的过程中发现逐渐演变为A型IAA；其他22例首次产前超声即诊断为IAA。3例胎儿分娩后经手术矫正，27例选择终止妊娠，4例宫内死亡。胎儿IAA的超声心动图主要表现包括：心脏四腔心切面左心室明显小于右心室或差别不明显；三血管切面显示主动脉明显小于肺动脉；三血管-气管切面和主动脉弓切面显示主动脉与降主动脉不能相连；主动脉弓切面显示主动脉弓弯曲度变小、走行僵直，主动脉、动脉导管和降主动脉之间失去正常的“V”字形结构。彩色多普勒超声检查显示主动脉弓中断处无连续血流信号，动脉导管内可见血流反转。对7例IAA胎儿进行透射电镜检测，结果显示主动脉弓近离断处的弹力膜之间存在大量平滑肌细胞，数量较升主动脉近端明显增多且排列紊乱，弹力膜较升主动脉近端增厚、走行扭曲；离断处系带无明显正常的内皮细胞和管腔，只有少量断裂坏死内皮细胞的痕迹，大量粗短且排列紊乱的弹力膜和纵横交错的平滑肌细胞无规律分布。结论: 产前超声心动图是诊断胎儿IAA的主要手段，通过术后追踪和尸体解剖发现胎儿IAA的并发症和疾病特征，有利于提高其诊断率；部分胎儿IAA可由AAD或CoA逐步演变而来，其发病机制可能与缺血缺氧和动脉导管收缩成分迁移有关。.

The increasing use of nanoparticles is driving the growth of research on their effects on living organisms. However, studies on the effects of nanoparticles on cellular respiration are still limited. The remodeling of cellular-respiration-related indices in plants induced by zinc oxide nanoparticles (nnZnO) and its bulk form (blZnO) was investigated for the first time. For this purpose, barley (Hordeum vulgare L.) seedlings were grown hydroponically for one week with the addition of test compounds at concentrations of 0, 0.3, 2, and 10 mg mL-1. The results showed that a low concentration (0.3 mg mL-1) of blZnO did not cause significant changes in the respiration efficiency, ATP content, and total reactive oxygen species (ROS) content in leaf tissues. Moreover, a dose of 0.3 mg mL-1 nnZnO increased respiration efficiency in both leaves (17 %) and roots (38 %). Under the influence of blZnO and nnZnO at medium (2 mg mL-1) and high (10 mg mL-1) concentrations, a dose-dependent decrease in respiration efficiency from 28 % to 87 % was observed. Moreover, the negative effect was greater under the influence of nnZnO. The gene transcription of the subunits of the mitochondria electron transport chain (ETC) changed mainly only under the influence of nnZnO in high concentration. Expression of the ATPase subunit gene, atp1, increased slightly (by 36 %) in leaf tissue under the influence of medium and high concentrations of test compounds, whereas in the root tissues, the atp1 mRNA level decreased significantly (1.6-2.9 times) in all treatments. A dramatic decrease (1.5-2.4 times) in ATP content was also detected in the roots. Against the background of overexpression of the AOX1d1 gene, an isoform of alternative oxidase (AOX), the total ROS content in leaves decreased (with the exception of 10 mg mL-1 nnZnO). However, in the roots, where the pressure of the stress factor is higher, there was a significant increase in ROS levels, with a maximum six-fold increase under 10 mg mL-1 nnZnO. A significant decrease in transcript levels of the pentose phosphate pathway and glycolytic enzymes was also shown in the root tissues compared to leaves. Thus, the disruption of oxidative phosphorylation leads to a decrease in ATP synthesis and an increase in ROS production; concomitantly reducing the efficiency of cellular respiration.

Autophagy, an intracellular self-degradation process, is governed by a complex interplay of signaling pathways and interactions between proteins and organelles. Its fundamental purpose is to efficiently clear and recycle cellular components that are damaged or redundant. Central to this process are autophagic vesicles, specialized structures that encapsulate targeted cellular elements, playing a pivotal role in autophagy. Despite growing interest in the molecular components of autophagic machinery and their regulatory mechanisms, capturing the detailed ultrastructural dynamics of autophagosome formation continues to present significant challenges. However, recent advancements in microscopy, particularly in electron microscopy, have begun to illuminate the dynamic regulatory processes underpinning autophagy. This review endeavors to provide an exhaustive overview of contemporary research on the ultrastructure of autophagic processes. By synthesizing observations from diverse technological methodologies, this review seeks to deepen our understanding of the genesis of autophagic vesicles, their membrane origins, and the dynamic alterations that transpire during the autophagy process. The aim is to bridge gaps in current knowledge and foster a more comprehensive comprehension of this crucial cellular mechanism.

In order to investigate the effects of multi-frequency ultrasound-assisted immersion freezing (MUIF) on the meat quality of Macrobrachium rosenbergii, tail meat was subjected to different MUIF treatments respectively, namely 20 + 40 kHz (MUIF-20 + 40), 20 + 60 kHz (MUIF-20 + 60), 40 + 60 kHz (MUIF-40 + 60) and 20 + 40 + 60 kHz (MUIF-20 + 40 + 60), and the immersion freezing (IF) as control. Results showed that average diameter of ice crystals was 28 μm in IF, and that was only 8 μm in MUIF-20 + 40 + 60. When compared to IF, MUIF alleviated oxidative deterioration of lipids and proteins, but only at higher ultrasound frequency (MUIF-40 + 60; MUIF-20 + 40 + 60). Carbonyl content of MUIF-20 + 40 + 60 was only 40% of that in IF. Similarly, protein denaturation was inhibited in MUIF (except for MUIF-20 + 40). Transmission electron microscopy showed greater distortion of the ultrastructural components in IF, MUIF-40 + 60, and MUIF-20 + 40 + 60, suggested by bended Z-line. In conclusion, MUIF can be an effective strategy to mitigate mechanical damage and protein deterioration in the meat of Macrobrachium rosenbergii.

The expansion of betel palm cultivation is driven by rising demand for betel nut, yet this growth is accompanied by challenges such as decreased agricultural biodiversity and the spread of infectious pathogens. Among these, Yellow Leaf Disease (YLD) emerges as a prominent threat to betel palm plantation. Areca Palm Velarivirus 1 (APV1) has been identified as a primary causative agent of YLD, precipitating leaf yellowing, stunted growth, and diminished yield. However, the precise mechanisms underlying APV1-induced damage remain elusive. Our study elucidates that APV1 infiltrates chloroplasts, instigating severe damage and consequential reductions in chlorophyll a/b and carotene levels, alongside notable declines in photosynthetic efficiency. Moreover, APV1 infection exerts broad regulatory effects on gene expression, particularly suppressing key genes implicated in chloroplast function and photosynthesis. These disruptions correlate with growth retardation, yield diminishment, and compromised nut quality. Intriguingly, the paradoxical destruction of the host\'s photosynthetic machinery by APV1 prompts inquiry into its evolutionary rationale, given the virus\'s dependence on host resources for replication and proliferation. Our findings reveal that APV1-induced leaf yellowing acts as a beacon for transmission vectors, hinting at a nuanced \"host-pathogen-vector co-evolutionary\" dynamic.