Epidermal Structures Research Articles

Foliar Epidermal Studies in Indian Jasminum

The paper reports epidermal structures including their appendages in thirty three species of jasminum. Various types of stomata including the abnormalities have been reported. Trichomes which are the characteristic of this genus have been observed in all the investigated species. Guticular striations and other important feature are also discussed in detail. Giant stomata and domatia are recorded for the first time in this genus. Species of Jasminum can be identified on the basis of epidermal features.

Foliar Anatomy of the Family Acanthaceae I. the Tribe Justiceae

The venation type, areole size, vein endings, vein tips and epidermal character have been described in 11 species of the tribe Justiceae of the family Acanthaceae. The features like unilacunar node, a prominent strand, venation patterns, structure of the epidermis, diamesogenous stomata, trichomes, lithocysts, etc. have been found to be useful in taxonomic considerations.

Foliar Epidermal Studies in Rosaceae II: Prunus

Foliar epidermal structure of 16 species of Prunus is described in this paper and its taxononiic significance is discussed.

P22 A single-cell map of the epigenomic landscape in keratinocytes exposed to the cytokine milieu of atopic dermatitis

Abstract Introduction and aims In atopic dermatitis (AD), induction of inflammatory responses regulated by cytokines such as of thymic stromal lymphopoietin exacerbate the disrupted integrity of the skin barrier. Cytokines, such as interleukin (IL)-4, IL-13 and IL-22, present in the skin milieu, bind to their corresponding receptors on the cell surface of keratinocytes, activating multiple signal transduction pathways that lead to changes in the gene expression profile of keratinocytes, in part, by modulating chromatin structure. Understanding the intricate interplay between cytokine-mediated signalling pathways in keratinocytes and the resulting epigenetic changes is essential for elucidating the pathogenesis of AD. In this study, we utilized high-throughput technology to examine the effects of cytokines on modulation of the epigenetic landscape at the keratinocyte single-cell level, and subsequent effects on the gene expression. Methods We utilized the reconstructed human epidermis model, an in vitro three-dimensional human epidermis model consisting of a polycarbonate membrane and keratinocytes mimicking the structure of native human epidermis. Following exposure to AD cytokine(s), the model gene expression and chromatin accessibility of target cells were analysed using single-cell multiomics approaches. Results Our preliminary data show that IL-4, IL-13 and IL-22 reduce the expression levels of the barrier-related gene filaggrin in keratinocytes. Conclusions Unlike genetic changes, epigenetic alterations are dynamic and can be restored to their normal state, which has major implications for the development of therapeutics for various diseases. This study will provide valuable insights into the epigenetic mechanisms underlying AD and present potential targets for epigenetic-related therapeutic interventions. These interventions can be used in combination with available compounds to reduce the recurrence of AD and improve the treatment efficiency.

An alkaloidal fraction of Annona tomentosa possesses anthelmintic activity and induces surface modifications in Haemonchus contortus

The nematode Haemonchus contortus is, as a parasite, responsible for most mortality of small ruminants, causing significant economic losses. Numerous plant-derived compounds have exhibited promising anthelmintic activities against this nematode. Notably, the Annona genus stands out for demonstrated anthelmintic effects by extracts from several of its species against different nematodes. This study aimed to assess the effect of an Annona tomentosa fraction, rich in alkaloids, on H. contortus. This fraction, named Alk.F, is derived from the methanolic extract of the plant’s stem bark. Chemical characterization of Alk.F was performed by liquid chromatography coupled with mass spectrometry. Among the nine predominant peaks obtained, seven alkaloids were identified: reticuline, reticuline N-oxide, reticuline N-oxide isomer, cyclanoline, asimilobine, tetrahydropalmatine and anonaine. Alk.F inhibited the larval development of H. contortus with an IC50 of 0.026 mg/mL, inhibited larval exsheathment with an IC50 of 0.38 mg/mL, and displayed low hemolytic activity towards sheep erythrocytes. Furthermore, atomic force microscopy revealed that Alk.F altered adhesive forces and the height profile on the surface of H. contortus larvae. In conclusion, A. tomentosa alkaloids alter the cuticle structure of H. contortus, inhibiting larval development and exsheathment, thus offering possibilities for contributing to the development of new anthelmintic drugs.

Glycolic acid-induced disruption of epidermal homeostasis in a skin equivalent model: Insights into temporal dynamics and mechanisms

Glycolic acid (GA) is extensively used in cosmetic formulations and skin peeling treatments but its adverse effects, notably severe disruption of epidermal structure, limit its clinical utility. However, the detailed impact of GA on epidermal homeostasis, including changes in structure and protein expression over time, is not fully understood. This study employed a reconstructed human epidermis (RHE) model to assess the effects of varying GA concentrations on epidermal proliferation, differentiation, and desquamation at different time points. Through histology, immunofluorescence, and immunohistochemistry, we observed that 35% GA concentration adversely caused abnormal epidermal homeostasis by affecting epidermal proliferation, differentiation and desquamation. Our findings reveal time-specific responses of key proteins to GA: Filaggrin, Involucrin, Loricrin, and Ki67 showed very early responses; KLK10 an early response; and AQP3 and K10 late responses. This research provides a detailed characterization of GA's effects in an RHE model, mimicking clinical superficial peeling and identifying optimal times for detecting GA-induced changes. Our results offer insights for designing interventions to mitigate GA's adverse effects on skin, enhancing the safety and efficacy of GA peeling treatments.

Research on the Drag Reduction Performance of Bionic Micro-gradient Surfaces

Long range and high speed are important performance indicators for modern naval equipment such as submarines and ships. Taking the special shield scale structure of shark epidermis as the research object, models of riblets, discontinuous riblets, equal-gradient riblets and shark-like micro-gradient riblets were established, and their effects on flow field characteristics were analyzed. Compared with smooth surfaces, the bionic micro-gradient surface had a maximum drag reduction rate of 9.93% under the combined action of streamwise vortices and spanwise secondary vortices, and maintained a good drag reduction effect over a wide speed range. The bionic micro-gradient surface provides a potential reference for underwater mechanical drag reduction design.

CLDN1 knock out keratinocytes as a model to investigate multiple skin disorders.

The transmembrane protein claudin-1 is critical for formation of the epidermal barrier structure called tight junctions (TJ) and has been shown to be important in multiple disease states. These include neonatal ichthyosis and sclerosing cholangitis syndrome, atopic dermatitisand various viral infections. To develop a model to investigate the role of claudin-1 in different disease settings, we used CRISPR/Cas9 to generate human immortalized keratinocyte (KC) lines lacking claudin-1 (CLDN1 KO). We then determined whether loss of claudin-1 expression affects epidermal barrier formation/function and KC differentiation/stratification. The absence of claudin-1 resulted in significantly reduced barrier function in both monolayer and organotypic cultures. CLDN1 KO cells demonstrated decreases in gene transcripts encoding the barrier protein filaggrin and the differentiation marker cytokeratin-10. Marked morphological differences were also observed in CLDN1 KO organotypic cultures including diminished stratification and reduced formation of the stratum granulosum. We also detected increased proliferative KC in the basale layer of CLDN1 KO organotypic cultures. These results further support the role of claudin-1 in epidermal barrier and suggest an additional role of this protein in appropriate stratification of the epidermis.

The cuticle proteome of a planktonic crustacean.

The cuticles of arthropods provide an interface between the organism and its environment. Thus, the cuticle's structure influences how the organism responds to and interacts with its surroundings. Here, we used label-free quantification proteomics to provide a proteome of the moulted cuticle of the aquatic crustacean Daphnia magna, which has long been a prominent subject of studies on ecology, evolution, and developmental biology. We detected a total of 278 high-confidence proteins. Using protein sequence domain and functional enrichment analyses, we identified chitin-binding structural proteins and chitin-modifying enzymes as the most abundant protein groups in the cuticle proteome. Structural cuticular protein families showed a similar distribution to those found in other arthropods and indicated proteins responsible for the soft and flexible structure of the Daphnia cuticle. Finally, cuticle protein genes were also clustered as tandem gene arrays in the D. magna genome. The cuticle proteome presented here will be a valuable resource to the Daphnia research community, informing genome annotations and investigations on diverse topics such as the genetic basis of interactions with predators and parasites.

Leaf ecological stoichiometry and anatomical structural adaptation mechanisms of Quercus sect. Heterobalanus in southeastern Qinghai–Tibet Plateau

BackgroundWith the dramatic uplift of the Qinghai–Tibet Plateau (QTP) and the increase in altitude in the Pliocene, the environment became dry and cold, thermophilous plants that originally inhabited ancient subtropical forest essentially disappeared. However, Quercus sect. Heterobalanus (QSH) have gradually become dominant or constructive species distributed on harsh sites in the Hengduan Mountains range in southeastern QTP, Southwest China. Ecological stoichiometry reveals the survival strategies plants adopt to adapt to changing environment by quantifying the proportions and relationships of elements in plants. Simultaneously, as the most sensitive organs of plants to their environment, the structure of leaves reflects of the long-term adaptability of plants to their surrounding environments. Therefore, ecological adaptation mechanisms related to ecological stoichiometry and leaf anatomical structure of QSH were explored. In this study, stoichiometric characteristics were determined by measuring leaf carbon (C), nitrogen (N), and phosphorus (P) contents, and morphological adaptations were determined by examining leaf anatomical traits with microscopy.ResultsDifferent QSH life forms and species had different nutrient allocation strategies. Leaves of QSH plants had higher C and P and lower N contents and higher N and lower P utilization efficiencies. According to an N: P ratio threshold, the growth of QSH species was limited by N, except that of Q. aquifolioides and Q. longispica, which was limited by both N and P. Although stoichiometric homeostasis of C, N, and P and C: N, C: P, and N: P ratios differed slightly across life forms and species, the overall degree of homeostasis was strong, with strictly homeostatic, homeostatic, and weakly homeostatic regulation. In addition, QSH leaves had compound epidermis, thick cuticle, developed palisade tissue and spongy tissue. However, leaves were relatively thin overall, possibly due to leaf leathering and lignification, which is strategy to resist stress from UV radiation, drought, and frost. Furthermore, contents of C, N, and P and stoichiometric ratios were significantly correlated with leaf anatomical traits.ConclusionsQSH adapt to the plateau environment by adjusting the content and utilization efficiencies of C, N, and P elements. Strong stoichiometric homeostasis of QSH was likely a strategy to mitigate nutrient limitation. The unique leaf structure of the compound epidermis, thick cuticle, well-developed palisade tissue and spongy tissue is another adaptive mechanism for QSH to survive in the plateau environment. The anatomical adaptations and nutrient utilization strategies of QSH may have coevolved during long-term succession over millions of years.

Panxianopteris taeniopteroides gen. et sp. nov., an anatomically preserved taeniopterid leaf from the upper Permian of Guizhou Province, China

Taeniopterid leaves with entire margins, prominent midribs and simple or bifurcate lateral veins are present in many Paleozoic and Mesozoic floras globally and were a typical and diverse element in the late Paleozoic equatorial Cathaysian flora. Most taeniopterid leaves are preserved as impression-compression fossils that reveal only information on their morphology and in some cases cuticle structure. Taeniopterid leaves preserved with anatomy are much rarer and have only previously been identified in the Mesozoic. Here we report a taeniopterid leaf from the upper Permian Xuanwei Formation in southwestern China that preserves morphology and anatomy. The leaf is over 18 cm long and 10 cm wide, with the lamina attached to the lateral sides of the midrib. Parallel lateral veins arise from the midrib which has longitudinal ridges on its adaxial surface and two distinct groups of vascular bundles. One group of bundles is adaxially located and arranged in a rough inverted Ω-shape, while the other is abaxially located and arranged in a ring. Individual bundles have endarch primary xylem and secondary xylem. Comparisons with other anatomically preserved taeniopterid leaves allow us to establish Panxianopteris taeniopteroides gen. et sp. nov. This vascular bundle arrangement is most comparable to the rachis of the Triassic Umkomasiales pteridosperm leaf Dicroidium fremouwensis from the Gondwanan flora. P. taeniopteroides is the first anatomically preserved taeniopterid leaf reported from the Paleozoic and the Cathaysian flora, and although its affinity remains enigmatic because it is only known from its isolated leaf, it is likely to be a pteridosperm allied with the Umkomasiales or their ancestral lineage.

Macromorphological and foliar epidermal anatomical characteristics of Lilium rosthornii (Liliaceae): Implications for morphological adaptations and taxonomic significance.

This research is to examine the macromorphological and foliar epidermal anatomical features of Lilium rosthornii Diels and its ability to plastically adapt to environmental forces, which is crucial for its taxonomic classification. L. rosthornii has macromorphological characteristics such as linear to lanceolate leaves of up to 20 cm in length and 2-3 cm in breadth, grouped in a whorled pattern. The blooms are voluminous and conspicuous, measuring up to 15 cm in diameter and are supported by a towering stalk that grows up to 1 m in height. The foliar epidermal structure of L. rosthornii exhibits a stomatal length of 82.02 ± 5.77 μm and a width of 29.19 ± 1.39 μm. These measurements suggest that the plant's stomata are influenced by its ploidy levels and may serve as adaptive mechanisms to enhance water consumption efficiency. The leaf structure shows a significant thickness of 398.74 ± 97.96 μm, which might potentially contribute to its ability to withstand environmental challenges. Additionally, the presence of defensive adaptations in the top and lower epidermal layers further supports this observation. The palisade tissue measurement (58.87 ± 9.56 m) and spongy tissue measurement (32.42 ± 12.72 μm) indicate a potential for photosynthetic optimization. Furthermore, there is a possible correlation between the vascular bundle width (28.15 ± 6.52 °m) and the efficiency of nutrition delivery. The results of this study emphasize the notable diversity in the foliar structures of L. rosthornii, offering valuable understanding of its morphological adaptations that have ecological and taxonomic significance. The findings provide a deeper comprehension of the potential impact of anatomical characteristics on plant function and categorization, hence providing significant insights to the domain of plant morphology and systematics. RESEARCH HIGHLIGHTS: Examines Lilium rosthornii's anatomical features and environmental adaptability for taxonomic relevance. Leaf thickness and epidermal defenses indicate resilience to environmental stress. Highlights the diversity in L. rosthornii's foliar structures, with implications for ecological and taxonomic significance Offers insights into the impact of anatomical characteristics on plant function and classification.

Omega-3 fatty acids mitigate skin damage caused by ultraviolet-B radiation

Mice fed a diet containing an adequate amount of ω-3 fatty acids (ω-3 Adq) or a deficient diet (ω-3 Def) were irradiated with ultraviolet-B (UV-B) and were measured daily changes in transepidermal water loss (TEWL). TEWL was significantly increased in ω-3 Def mice with repeated UV-B irradiation, but this increase was significantly reduced in ω-3 Adq mice. The epidermal layers revealed thickening of the spinous and basal layers induced by UV-B irradiation in both groups. Moreover, the ω-3 Def mice had a disturbed epidermal structure and a coarser stratum corneum. And the granule cell layer is significantly reduced, and abnormal layer formation (parakeratosis) occurred in the stratum corneum. These results suggest that continuous UV-B irradiation promotes epidermal turnover and leads to epidermal thickening, but ω-3 fatty acids protect the body from UV-B-induced stress.

In vivo assessment of early effects of diamond-tipped microdermabrasion through the lens of line-field confocal optical coherence tomography.

Microdermabrasion is a cosmetic procedure that has gained popularity for skin rejuvenation by causing repetitive intraepidermal injury to stimulate the proliferation of fibroblasts and collagen production. Various clinical studies have demonstrated microdermabrasion's effectiveness in skin rejuvenation; however, most of these studies rely on clinical observation and scoring by observers rather than histologic or microscopic analysis. In our single-center prospective study, we used line-field confocal optical coherence tomography (LC-OCT), to non-invasively visualize the early effects of one microdermabrasion treatment on the facial epidermal and dermal structure. Using LC-OCT, this study aims to elucidate the microscopic and histological effects of microdermabrasion on epidermal and dermal structures, including epidermal thickness, as well as collagen and vascular patterns. Eight volunteers (Fitzpatrick skin types II-V) underwent one treatment of microdermabrasion. LC-OCT and VISIA imaging were performed before and 10 min after microdermabrasion, and at 48-h follow-up. Subjective evaluations of skin texture and adverse reactions were assessed 1 week posttreatment via a telephone call. Compared to LC-OCT images before treatment, images captured after one treatment of microdermabrasion showed a decrease in thickness and number of undulations in the stratum corneum. In the superficial dermis, enhancement in fibrillar collagen, as demonstrated by an increased prominence of crisscrossing hyper-refractile strands, was visualized. This was consistent with subjective and objective improvement in facial rhytids calculated by VISIA skin analysis. Treatment monitoring with LC-OCT demonstrated consistent histopathological changes with clinical visual improvement. Therefore, LC-OCT, has the potential to enable long-term histopathological monitoring of microdermabrasion and other cosmetic procedures without biopsy.

Micromorphology and silicon of the leaf epidermis in the psammophyte Alyssum desertorum are sensitive to soil flooding.

The ultrastructure of the leaf epidermis and the localization and content of silicon in epidermal cells of the psammophyte Alyssum desertorum Stapf (Brassicaceae) were investigated using electron microscopy and laser confocal microscopy. The study aimed to examine the effect of flooding on the epidermal structure of the leaves, study the presence, localization, and content of silicon in the epidermal cells and determine whether changes in soil moisture affect the silicon content in the leaf epidermis. Silicon inclusions were observed in trichomes and typical epidermal cells on both leaf surfaces, with varying content depending on the cell type, leaf surface, and conditions growth. Soil flooding was found to influence the leaf epidermis ultrastructure and the silicon content in the epidermal cells of A. desertorum. Trichomes and pavement cells were identified as the main accumulators of silicon inclusions and wax-like structures. These findings suggest that changes in leaf microstructure and silicon content contribute to the normal functioning of psammophyte plants and can be considered signs of plant phenotypic plasticity and adaptive markers depending on water supply conditions.

Chemical and structural heterogeneity of olive leaves and their trichomes

Many biological surfaces have hairs, known as trichomes in plants. Here, the wettability and macro- and micro-scale features of olive leaves are analyzed. The upper leaf side has few trichomes, while the lower side has a high trichome density. By combining different techniques including electron and atomic force microscopy, trichome surfaces are found to be chemically (hydrophilic-hydrophobic) heterogeneous at the nano-scale. Both olive leaf surfaces are wettable by water, having a high water contact angle hysteresis and great drop adhesion. The ultra-structural pattern observed for epidermal pavement cells differs from the reticulate cuticle structure of trichomes which shows that leaf surface areas may be substantially different despite being located nearby. Our study provides evidence for the nano-scale chemical heterogeneity of a trichome which may influence the functional properties of biological surfaces, such as water and solute permeability or water capture as discussed here for plants.

Mechanism of self-recovery of hydrophobicity after surface damage of lotus leaf

The surfaces of lotus leaves with micro- and nano-waxy cuticle structures are superhydrophobic and possess a self-healing ability to regain hydrophobicity after damage. Inspired by this phenomenon, the problem of water-repellent coatings used in natural environments failing to perform after damage can be solved if these coatings are endowed with rapid self-repair and self-growth functions. However, there has been almost no exploration into the hydrophobicity self-repair process in lotus leaves. The changes in surface morphology during the hydrophobicity recovery process are not understood. There is a lack of research on the hydrophobicity recovery in lotus leaves. In this study, the damage and recovery experiments on lotus leaf surfaces were carried out in an artificial climate chamber, and the water repellency recovery process and typical water repellency roughness parameters regained time were obtained. Upon analyzing the differences in the recovery process of different damage types, the recovery mechanism after lotus leaf surface damage was obtained. Finally, it was found that the microscopic roughness determined the static contact angle (WCA) of the lotus leaf surface, and the nanoscopic roughness determined the rolling angle (SA). The dual factors of the recovery of the extruded epidermal tissue and the regeneration of the epidermal wax crystals determined the hydrophobicity recovery process in damaged lotus leaves.

Fabrication and In-Vivo Evaluation of Polyvinyl pyrrolidone/Poloxamer 188 Hybrid Nanofibers of Deflazacort

The superior flexibility, efficient drug loading, high surface-to-volume ratio, ease of formulation, and cost-controlled production are considered exceptional advantages of nanofibers (NFs) as a smart delivery system. Deflazacort (DEF) is an anti-inflammatory and immunosuppressant agent. It is categorized as a poorly soluble class II drug. In this study, DEF-loaded polymeric nanofibrous using the electrospinning technique mats, Polyvinyl pyrrolidone (PVP) with or without Poloxamer 188 (PX) were used as mat-forming polymers. Microscopical imaging, drug content (%), and in vitro dissolution studies were conducted for all NFs formulae (F1-F7). All NFs improved the DEF dissolution compared to the unprocessed form, with the superiority of the PVP/PX hybrid. The optimized formula (F7) exhibited an average diameter of 655.46 ± 90.4 nm and % drug content of 84.33 ± 5.58. The dissolution parameters of DEF loaded in PVP/PX NFs (F7) reflected a release of 95.3 % ± 3.1 and 102.6 % ± 1.7 after 5 and 60 min, respectively. NFs (F7) was investigated for drug-polymer compatibility using Fourier-Transform Infrared Spectroscopy (FTIR), Powder X-ray diffraction analysis (PXRD), and Differential Scanning Calorimetry (DSC). In vivo anti-inflammatory study employing male Sprague-Dawley rats showed a significant reduction of rat paw edema for F7 (p < 0.05) compared with unprocessed DEF with a normal epidermal and dermal skin structure comparable to the healthy negative control. Immunohistochemical and morphometric data displayed similarities between the immune reaction of F7 and the negative healthy control. The finding of this work emphasized that DEF loaded in PVP/PX NFs could be considered a useful strategy for enhancing the therapeutic performance of DEF.

Discovery of Pesticide Candidates from Natural Plant Products: Semisynthesis and Characterization of Andrographolide-Based Esters and Study of Their Pesticidal Properties and Toxicology.

To explore the use of nonfood plant-derived secondary metabolites for plant protection, a series of ester derivatives for controlling the major migratory agricultural pests were obtained by structural modification of andrographolide, a labdane diterpenoid isolated from Andrographis paniculata. Compound Id showed good insecticidal activity against the fall armyworm Spodoptera frugiperda Smith. Compounds IIa (LC50: 0.382 mg/mL) and IIIc (LC50: 0.563 mg/mL), the acaricidal activities of which were, respectively, 13.1 and 8.9 times that of andrographolide (LC50: 4.996 mg/mL), exhibited strong acaricidal and control effects against Tetranychus cinnabarinus Boisduval. Against Aphis citricola Van der Goot, compounds IIIc and IVb displayed 3.9- and 3.7-fold pronounced aphicidal activity of andrographolide. Effects of compound Id on three protective enzymes (superoxide dismutase, peroxidase, and catalase) of S. frugiperda were also observed. The obvious differences of epidermal cuticle structures of mites treated with compound IIa were determined by scanning electron microscopy. Structure-activity relationships indicated that 14-ester derivatives of andrographolide showed potential insecticidal/acaricidal activities and can be further utilized as lead compounds.

Immunohistochemical and Histopathological Characterization of Spina Bifida Defect Tissues Removed After Prenatal and Postnatal Surgical Repair

Background: Myelomeningocele or spina bifida is an open neural tube defect that is characterized by protrusion of the meninges and the spinal cord through a deformity in the vertebral arch and spinous process. Myelomeningocele of post-natal tissue is well described; however, pre-natal tissue of this defect has no known previous histologic characterization. We compared the histology of different forms of pre-natal myelomeningocele and post-natal myelomeningocele tissue obtained via prenatal intrauterine and postnatal surgical repairs. Methods: Pre-and post-natal tissues from spina bifida repair surgeries were obtained from lipomyelomeningocele, myeloschisis, and myelomeningocele spina bifida defects. Tissue samples were processed for H&E and immunohistochemical staining (KRT14 and p63) to assess epidermal and dermal development. Results: Prenatal skin near the defect site develops with normal epidermal, dermal, and adnexal structures. Within the grossly cystic specimens, histology shows highly dense fibrous connective tissue with complete absence of a normal epidermal development with a lack of p63 and KRT14 expression. Conclusion: Tissues harvested from prenatal and postnatal spina bifida repair surgeries appear as normal skin near the defect site. However, cystic tissues consist of highly dense fibrous connective tissue with complete absence of normal epidermal development.