Ultrastructural Observations Research Articles

Three-dimensional fine structures in deep fascia revealed by combined use of cryo-fixed histochemistry and low-vacuum scanning microscopy

Recent physiological studies have shown that the deep fascia has received much attention concerning clinical medicine; however, histological examination of the deep fascia has not been well established. In this study, we aimed to clarify and visualize the structure of the deep fascia by taking advantage of cryofixation techniques and low-vacuum scanning electron microscopy. As a result, the ultrastructural observations revealed three-dimensional stratification of the deep fascia composed of three layers: the first superficial layer consisting of collagen fibers extending in various directions with blood vessels and peripheral nerves; the second intermediate layer formed by single straight and thick collagen fibers with flexibility; and the third deepest layer, consisting of relatively straight and thin collagen fibers. We explored the use of two hooks to hold a piece of deep fascia in place through the course of cryo-fixation. A comparative observation with or without the hook-holding procedure would indicate the morphological adaptation to physiological stretch and contraction of the deep fascia. The present morphological approach paves the way to visualize three-dimensional ultrastructures for future biomedical studies including clinical pathophysiology.

843 Atypical epidermolytic palmoplantar keratoderma is a mild phenotypic variant of epidermolytic ichthyosis: A new proposal from ultrastructural observations and pro-inflammatory cytokine analyses

843 Atypical epidermolytic palmoplantar keratoderma is a mild phenotypic variant of epidermolytic ichthyosis: A new proposal from ultrastructural observations and pro-inflammatory cytokine analyses

Rhubarb Anthraquinones Ameliorates Inflammatory Lung Injury by Enhancing Alveolar Epithelium Tight Junction Proteins through RhoA/ROCK1 Signalling

Background: Leakage of the alveolar epithelial barrier can lead to pulmonary oedema, leading to organ dysfunction. Objectives: Combination anthraquinone (CA) and free anthraquinone (FA) were extracted from Rhubarb, and the prevention and therapeutic effects of Rhubarb anthraquinones (RA) on lipopolysaccharide (LPS)-induced lung injury were investigated. Materials and Methods: The CA and FA were extracted from Rhubarb by water solvent extraction and ethanol solvent extraction. The extracted RA content was determined using spectrophotometry and high-performance liquid chromatography (HPLC). A mouse model of inflammatory lung injury was established by LPS induction to study the mechanism of RA activity. Inflammatory factors were measured using an enzyme-linked immunosorbent assay. Changes in alveolar epithelial leakage were assessed using a permeability assay. Changes in lung injury were evaluated by histopathological and ultrastructural observations. Tight junction (TJ) markers and Ras homolog gene family member A (RhoA)/Rho-associated protein kinase 1 (ROCK1) pathway-related proteins were measured using immunohistochemistry and Western blotting. As an agonist of RhoA/Rock signalling, U46619 was used to further verify whether RA acts through this pathway. Results: RA could inhibit pulmonary inflammation by decreasing the level of inflammatory factors. The alveolar epithelial permeability was reduced, and the pathological injury of the lung tissue was alleviated after administration with RA. Furthermore, the expression of TJ proteins was up regulated and RhoA/ROCK1 signalling was inhibited in the presence of RA. The effects of RA on TJ proteins were partially reversed by U46619. Conclusion: RA effectively protects mice against inflammatory lung injury by enhancing alveolar epithelial TJ via RhoA/ROCK1 signalling.

Modifications in Ultrastructural Characteristics and Redox Status of Plants under Environmental Stress: A Review.

The rate of global environmental change is unprecedented, with climate change causing an increase in the oscillation and intensification of various abiotic stress factors that have negative impacts on crop production. This issue has become an alarming global concern, especially for countries already facing the threat of food insecurity. Abiotic stressors, such as drought, salinity, extreme temperatures, and metal (nanoparticle) toxicities, are recognized as major constraints in agriculture, and are closely associated with the crop yield penalty and losses in food supply. In order to combat abiotic stress, it is important to understand how plant organs adapt to changing conditions, as this can help produce more stress-resistant or stress-tolerant plants. The investigation of plant tissue ultrastructure and subcellular components can provide valuable insights into plant responses to abiotic stress-related stimuli. In particular, the columella cells (statocytes) of the root cap exhibit a unique architecture that is easily recognizable under a transmission electron microscope, making them a useful experimental model for ultrastructural observations. In combination with the assessment of plant oxidative/antioxidative status, both approaches can shed more light on the cellular and molecular mechanisms involved in plant adaptation to environmental cues. This review summarizes life-threatening factors of the changing environment that lead to stress-related damage to plants, with an emphasis on their subcellular components. Additionally, selected plant responses to such conditions in the context of their ability to adapt and survive in a challenging environment are also described.

Clinicopathological and immunological features of new onset kidney disease: a rare event after SARS-CoV-2 vaccination.

The onset of various kidney diseases has been reported after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. However, detailed clinical and pathological features are lacking. We screened and analyzed patients with newly diagnosed kidney diseases after inactivated SARS-CoV-2 vaccination in Peking University First Hospital from January 2021 to August 2021, and compared them with the reported cases in the literature. We obtained samples of blood, urine and renal biopsy tissues. Clinical and laboratory information, as well as light microscopy, immunostaining and ultrastructural observations, were described. The SARS-CoV-2 spike protein and nucleoprotein were stained using the immunofluorescence technique in the kidney biopsy samples. SARS-CoV-2 specific antibodies were tested using magnetic particle chemiluminescence immunoassay. The study group included 17 patients with a range of conditions including immune-complex-mediated kidney diseases (IgA nephropathy, membranous nephropathy and lupus nephritis), podocytopathy (minimal change disease and focal segmental glomerulosclerosis) and others (antineutrophil-cytoplasmic-antibody-associated vasculitis, anti-glomerular basement membrane nephritis, acute tubulointerstitial nephritis and thrombotic microangiopathy). Seven patients (41.18%) developed renal disease after the first dose and ten (58.82%) after the second dose. The kidney disease spectrum as well as clinicopathological features are similar across different types of SARS-CoV-2 vaccines. We found no definitive evidence of SARS-CoV-2 spike protein or nucleoprotein deposition in the kidney biopsy samples. Seropositive markers implicated abnormal immune responses in predisposed individuals. Treatment and follow-up (median=86 days) showed that biopsy diagnosis informed treatment and prognosis in all patients. In conclusion, we observed various kidney diseases following SARS-CoV-2 vaccine administration, which show a high consistency across different types of SARS-CoV-2 vaccines. Our findings provide evidence against direct vaccine protein deposition as the major pathomechanism, but implicate abnormal immune responses in predisposed individuals. These findings expand our understanding of SARS-CoV-2 vaccine renal safety.

Extracellular Vesicles in the Arbuscular Mycorrhizal Symbiosis: Current Understanding and Future Perspectives

The arbuscular mycorrhizal (AM) symbiosis is an ancient and highly conserved mutualism between plant and fungal symbionts, in which a highly specialized membrane-delimited fungal arbuscule acts as the symbiotic interface for nutrient exchange and signaling. As a ubiquitous means of biomolecule transport and intercellular communication, extracellular vesicles (EVs) are likely to play a role in this intimate cross-kingdom symbiosis, yet, there is a lack of research investigating the importance of EVs in AM symbiosis despite known roles in microbial interactions in both animal and plant pathosystems. Clarifying the current understanding of EVs in this symbiosis in light of recent ultrastructural observations is paramount to guiding future investigations in the field, and, to this end, this review summarizes recent research investigating these areas. Namely, this review discusses the available knowledge regarding biogenesis pathways and marker proteins associated with the various plant EV subclasses, EV trafficking pathways during symbiosis, and the endocytic mechanisms implicated in the uptake of these EVs. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Mitocytosis Is Critical for Phthalate-Induced Injury to the Ovarian Granulosa Cell Layer in Quail (Coturnix japonica)

Phthalates are widely used synthetic chemicals that determine endocrine disruption effects on female reproductivity and oviposition. Our study demonstrated that the mitochondrial quality in ovarian granulosa cells (GCs) is associated with a poor prognosis in female reproduction. However, the molecular mechanism of di-(2-ethylhexyl) phthalate (DEHP) exposure on the quail ovarian GC layer is still unknown. To validate the effects of DEHP on the GC layer, 8 days' old 150 female Japanese quail were treated orally with DEHP (250, 500, and 750 mg/kg BW/day) for 45 days to explore the toxic effects of DEHP on the ovarian GC layer. Histopathological assessment and ultrastructure observation found that DEHP decreased the thickness of the GC layer, resulted in mitochondrial damage, and activated mitocytosis. Additionally, the results further suggested that DEHP impacted the secretion of steroid hormones (reduced FSH, E2, and T levels and boosted Prog, PRL, and LH levels) by triggering mitocytosis (enhanced transcription of MYO19 and protein of KIF5B levels), mitochondrial dynamics (increasing mRNA and protein levels of OPA1, DRP1, MFN1, and MFN2), mitophagy (increasing mRNA and protein levels of Parkin, LC3B, and P62), and inducing GC function disorder. In conclusion, our research provided a new idea to explain the mechanism of DEHP toxicity of the ovarian GC layer in quail and presented insights into the role of mitocytosis in DEHP-induced ovarian GC layer injury.

Evaluation of Inhibitory Effect and Mechanism of Euphorbia Factor L3 against Phytophthora capsici

Phytophthora capsici is a highly destructive phytopathogenic oomycete with a broad host range and is responsible for tremendous losses. Euphorbia factor L3 (EFL3) is a natural plant-derived compound that has been widely studied in medicine and cosmetic applications. In this study, the sensitivity of 105 P. capsici isolates to EFL3 was determined, and the biological activity and physiological effects of EFL3 against P. capsici were investigated. The median effective concentration (EC50) values for EFL3 inhibition mycelial growth and spore germination ranged from 0.66 to 8.94 μg/mL (mean, 2.96 ± 0.91 μg/mL) and 1.63 to 13.16 μg/mL (mean, 5.30 ± 1.64 μg/mL), respectively. EFL3 treatment resulted in cell wall and cell membrane damage of P. capsici, which was revealed by morphological and ultrastructural observations, propidium iodide (PI) and calcofluor white (CFW) staining, and measurements of relative conductivity as well as malondialdehyde (MDA) and glycerol contents. In addition, the contents of phospholipid and cellulose, which are the major components of cell membrane and cell wall, were significantly reduced following EFL3 treatment. Furthermore, EFL3 provided protective as well as curative efficacies against P. capsici on detached tomato leaves and pepper seedlings in vivo. These data show that EFL3 exhibits strong inhibitory activity against P. capsici, thereby suggesting that it could be an effective alternative for controlling P. capsici-induced diseases.

UBE2C-mediated Autophagy Inhibition via Ubiquitination of SIRT1 Contributes to Endometrial Cancer Progression.

Our study highlights the tumorigenic role and regulatory mechanism of UBE2C in endometrial cancer; UBE2C inhibits endometrial cancer cell apoptosis through autophagy-related mechanisms and our findings provide new insights into the treatment of endometrial cancer.

Maleic hydrazide prompting growth and delaying senescence of mother frond in S. Polyrriza 7498

The effect and function mechanism of maleic hydrazide on the growth of mature leaves is unclear. Duckweed is widely used as a model plant to study the effect of compounds on plant growth. The observation of section and ultrastructure of the fronds, the comparation of SOD enzyme activity and related-gene transcriptional expression level showed that 75 μg/mL maleic hydrazide could prompt the growth of the mother fronds in S. Polyrriza 7498. The half-mother fronds (without meristematic tissue, cut from the mother fronds) with little meristematic tissue could repair themselves and delay their senescence by 75 μg/mL MH. The mother fronds turned more greener with 50 μg/mL MH and exogenous 0.1 μmol/L 6-BA (a kind of cytokinin) treatment, as well as with the increasing of fresh and dry weight in S. Polyrriza 7498. RNA-Seq data found that the happy growth of the mother fronds caused by MH, was probably resulted from up-regulating the expression of gene related to the synthesis and signaling transduction of cytokinin in S. Polyrriza 7498. Which are responsible for the maintaining membrane system integrate and transport protein function. The work gives lights to the study of function mechanism of MH prompting mature leaves growth and delaying mature leaves senescence in plant. And it provides a strategy to increase biomass with the application of low concentration MH and 6-BA in the same time in agriculture.

Kidney injury molecule-1 and podocalyxin dysregulation in an arginine vasopressin induced rodent model of preeclampsia

ObjectiveTo assess renal injury in an arginine vasopressin (AVP) rodent model of preeclampsia. Study designUrinary expression of kidney injury molecule-1 (KIM-1), urinary protein and creatinine was determined in rodents (n = 24; pregnant AVP, pregnant saline, non-pregnant AVP and non-pregnant saline), which received a continuous dose of either AVP or saline via subcutaneous mini osmotic pumps for 18 days, using a Multiplex kidney toxicity immunoassay. Renal morphology was assessed using haematoxylin and eosin staining and transmission electron microscopy. The immunolocalization of KIM-1 and podocalyxin was qualitatively evaluated using immunohistochemistry. ResultsUrinary KIM-1 and urinary protein levels were significantly increased in treated vs. untreated rats on gestational days 8 (p < 0.05), 14 (p < 0.001) and 18 (p < 0.001). The pregnant rats displayed a lower trend of creatinine compared to the non-pregnant groups, albeit non-significantly. KIM-1 was immunolocalized in the proximal convoluted tubules in AVP treated vs. untreated groups. In contrast, podocalyxin was weakly immunostained within glomeruli of pregnant AVP treated vs. pregnant untreated rats. Histological evaluation revealed reduced Bowman’s space, with some tubular and blood vessel necrosis in the pregnant treated group. Ultrastructural observations included effacement and fusion of podocyte foot processes, glomerular basement membrane abnormalities, podocyte nuclear crenations, mitochondrial oedema and cristae degeneration with cytoplasmic lysis within treated tissue. ConclusionOur findings demonstrate region-specific kidney injury particularly glomerular impairment and endothelial injury in AVP-treated rats. The findings highlight the utility of this model in studying the mechanisms driving renal damage in a rodent model of preeclampsia.

Transcriptomic profiling and differential analysis reveal the renal toxicity mechanisms of mice under cantharidin exposure

Cantharidin (CTD), extracted from the traditional Chinese medicine mylabris, has shown significant curative effects against a variety of tumors, but its clinical application is limited by its high toxicity. Studies have revealed that CTD can cause toxicity in the kidneys; however, the underlying molecular mechanisms remain unclear. In this study, we investigated the toxic effects in mouse kidneys following CTD treatment by pathological and ultrastructure observations, biochemical index detection, and transcriptomics, and explored the underlying molecular mechanisms by RNA sequencing (RNA-seq). The results showed that after CTD exposure, the kidneys had different degrees of pathological damage, altered uric acid and creatinine levels in serum, and the antioxidant indexes in tissues were significantly increased. These changes were more pronounced at medium and high doses of CTD. RNA-seq analysis revealed 674 differentially expressed genes compared with the control group, of which 131 were upregulated and 543 were downregulated. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that many differentially expressed genes were closely related to the stress response, the CIDE protein family, and the transporter superfamily, as well as the MAPK, AMPK, and HIF-1 pathways. The reliability of the RNA-seq results was verified by qRT-PCR of the six target genes. These findings offer insight into the molecular mechanisms of renal toxicity caused by CTD and provide an important theoretical basis for the clinical treatment of CTD-induced nephrotoxicity.

Alkali exposure induces autophagy through activation of the MAPKpathway by ROS and inhibition of mTOR in Eriocheir sinensis

Saline-alkali water is widely distributed around the world, and salinization of water ecosystems has occurred in some areas of the world, comprising approximately one-third of the total land area, which has drawn much attention to the conservation of water ecosystems and aquatic animals. However, due to the complex composition of saline-alkaline water, many aquatic animals are unable to survive, which greatly limits the development and utilization of saline-alkaline waters. Carbonate alkalinity is an important stress factor for aquatic animals in saline–alkaline water. Exposure to highly alkaline carbonate can induce oxidative stress. For this study, we used Eriocheir sinensis as a model organism to evaluate the effects of alkaline stress on oxidative stress and autophagy. The trial was divided into five alkali level treatment groups (control, 4.375 mmol/L, 8.75 mmol/L, 17.5 mmol/L, and 35 mmol/L, respectively), and liver tissues were assessed by antioxidant enzyme kits, real-time quantitative PCR assays and ultrastructural observations at 3 time points (24 h, 48 h, 96 h). Compared with the control group, the activities of antioxidant enzymes (superoxide dismutase (SOD), glutathione reductase (GSH), glutathione peroxidase (GSH-PX) and total antioxidant capacity (T-AOC)) in the alkali stress group increased and then decreased with increasing time, while the content of malondialdehyde (MDA) increased. At the molecular level, the expression of MAPK pathway-related genes (P38, MAPK, JNK) in the alkaline stress group showed a dose-dependent increase at 48 and 96 h and was significantly higher than that in the control group. The expression of autophagy-related genes (ATG5, ATG12, ATG7 and GABARAP) increased dose-dependently at 24, 48, and 96 h and was significantly higher than that in the control group. In contrast, mTOR expression was always in a suppressed state. These results suggest that alkaline stress induces activation of the MAPK pathway via ROS and inhibits mTOR expression, thereby inducing autophagy in the liver tissue of Eriocheir sinensis. This study investigated the stress mechanism of carbonate on Eriocheir sinensis and provided a theoretical basis for the continued exploitation of saline-alkaline water aquaculture.

Cortical atrophy in chronic subdural hematoma from ultra-structures to physical properties

Several theories have tried to elucidate the mechanisms behind the pathophysiology of chronic subdural hematoma (CSDH). However, this process is complex and remains mostly unknown. In this study we performed a retrospective randomised analysis comparing the cortical atrophy of 190 patients with unilateral CSDH, with 190 healthy controls. To evaluate the extent of cortical atrophy, CT scan images were utilised to develop an index that is the ratio of the maximum diameter sum of 3 cisterns divided by the maximum diameter of the skull at the temporal lobe level. Also, we reported, for the first time, the ultrastructural analyses of the CSDH using a combination of immunohistochemistry methods and transmission electron microscopy techniques. Internal validation was performed to confirm the assessment of the different degrees of cortical atrophy. Relative Cortical Atrophy Index (RCA index) refers to the sum of the maximum diameter of three cisterns (insular cistern, longitudinal cerebral fissure and cerebral sulci greatest) with the temporal bones' greatest internal distance. This index, strongly related to age in healthy controls, is positively correlated to the preoperative and post-operative maximum diameter of hematoma and the midline shift in CSDH patients. On the contrary, it negatively correlates to the Karnofsky Performance Status (KPS). The Area Under the Receiver Operating Characteristics (AUROC) showed that RCA index effectively differentiated cases from controls. Immunohistochemistry analysis showed that the newly formed CD-31 positive microvessels are higher in number than the CD34-positive microvessels in the CSDH inner membrane than in the outer membrane. Ultrastructural observations highlight the presence of a chronic inflammatory state mainly in the CSDH inner membrane. Integrating these results, we have obtained an etiopathogenetic model of CSDH. Cortical atrophy appears to be the triggering factor activating the cascade of transendothelial cellular filtration, inflammation, membrane formation and neovascularisation leading to the CSDH formation.

Invasive pulmonary aspergillosis with candidiasis: usefulness of molecular and ultrastructural morphological analysis on FFPE tissue for invasive fungal infections.

Invasive pulmonary aspergillosis (IPA) is one of the most frequent forms of invasive fungal infections (IFI); however, it is often difficult to identify the pathogenic fungal species and to select appropriate treatments for patients with IFI including IPA. Here, we describe the detailed pathophysiology of an autopsy case of severe respiratory failure due to IPA with candidiasis. The patient developed severe respiratory failure after influenza infection and died, and the autopsy revealed a mixed disease of IPA with candidiasis. In this study, in addition to the routine pathological examination, we further examined formalin-fixed paraffin-embedded (FFPE) tissues by scanning electron microscopy (SEM) and partial genomic DNA sequencing. Although optical microscopy alone was insufficient to identify the pathogenic organisms, SEM clearly depicted the characteristic morphology of Aspergillus sp. and Candida sp. as closely overlapping in a nested fashion, providing evidence of mixed infection of both fungal species in a focal site. The technique using FFPE tissue in combination with ultrastructural observation by SEM, elemental analysis by SEM-EDX, and DNA sequencing is promising for analyzing the pathophysiology of IFI.

Curcumin promotes microglial M2 polarization and suppresses chronic constriction: Injury-induced neuropathic pain in a rat model of peripheral neuropathy

ObjectivesGlia (i.e., astrocyte and microglia) activation in the central nervous system plays a critical role in developing neuropathic pain. Microglia can be activated into proinflammatory (M1) and anti-inflammatory (M2) phenotypes. Switching microglial polarization from M1 to M2 phenotypes represents a novel therapeutic strategy for neuropathic pain. Curcumin has been widely used for its anti-inflammatory and immunomodulatory effects. This study investigated effects of curcumin on astrocyte activation and microglia polarization in the cuneate nucleus (CN) and development of neuropathic pain behavior after chronic constriction injury (CCI) of the median nerve. MethodsRats were fed with curcumin once daily at a dose of 40, 80, or 120 mg/kg 30 min before and until 7 d after median nerve CCI. Subsequently, mechanical allodynia and thermal hyperalgesia were evaluated using von Frey filaments and plantar tests, respectively. The levels of astrocyte marker, monoclonal glial fibrillary acidic protein; microglia marker, ionized calcium-binding adapter molecule 1; M1 marker, CD86; and M2 marker, CD206 in the cuneate nucleus were determined. Enzyme-linked immunosorbent assay was applied to measure cytokine concentrations. ResultsCurcumin administration dose-dependently reduced mechanical allodynia and thermal hyperalgesia and decreased monoclonal glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 immunoreactivity in the ipsilateral cuneate nucleus after CCI. On ultrastructural observation, curcumin treatment was associated with fewer features of activated astrocytes and microglia. Furthermore, CCI rats given curcumin exhibited a decline in CD86 immunoreactivity and proinflammatory cytokine levels but an increase in CD206 immunoreactivity and release of anti-inflammatory cytokines. ConclusionsIn our findings, curcumin switches microglial phenotypes from M1 to M2 by suppressing astrocytic activation, reducing proinflammatory cytokine release, promoting anti-inflammatory cytokine production, and contributing to relief of neuropathic pain.

Electroacupuncture reverses endothelial cell death and promotes angiogenesis through the VEGF/Notch signaling pathway after focal cerebral ischemia-reperfusion injury.

Angiogenesis is an important mechanism of recovery from ischemic stroke. Recent studies have found that there is a close relationship between the VEGF/Notch pathway and angiogenesis. It is unknown whether EA can exert a brain protection effect and promote angiogenesis by acting on the VEGF/Notch signaling pathway after focal cerebral ischemia-reperfusion injury (CIRI). The Middle Cerebral Artery occlusion/Reperfusion (MCAo/R) model was established, in which rats were subjected to occlusion with ischemic intervention for 30min, followed by reperfusion for 8h, 1 day, 3 days, and 7 days. The first EA treatment was performed 90 min after the animal model was successfully established, and then EA treatments were performed once a day for 7 days. The 2,3,5-triphenyltetrazolium chloride staining and neurological deficit examination were performed to assess the level of CIRI and neuroprotection by EA. Expression levels of VEGFA, Notch1, and Hes1 proteins were measured via western blotting, while the morphological changes of ECs and microvasculature in the cortex were determined using an ultrastructural observation method. EA treatment of PC6, GV26, and SP6 can significantly improve the neurological function of MCAO/R rats, reduce the volume of cerebral infarction, and modulate the ultrastructure of ECs and microvessels in pathological states. Western blotting revealed that EA increased VEGFA protein expression at 8h and 3 days after CIRI, as well as Notch1 protein expression at 1 and 7 days. Subsequently, EA activated the VEGF/Notch pathway, increasing the expression of the downstream target protein Hes1, reversing EC death, and promoting angiogenesis. Our findings showed that EA plays a role in promoting angiogenesis following focal CIRI, and we hypothesized that this was due to the regulation of ECs by the EA-activated VEGF/Notch signaling pathway.

Ultrastructural observation and transcriptome analysis provide insights into mechanisms of Penicillium expansum invading apple wounds

Penicillium expansum is a pathogen causing enormous postharvest losses of fruits, especially apples. In this study, we first investigated the morphological changes of P. expansum within apple wounds during infectious process by microscopic observation. We found that conidia swelled and secreted potential hydrophobin in 4 h, germinated in 8 h, and finally formed conidiophores in 36 h, a critical control time point to prevent the second contamination of spores. We then compared the transcript accumulation of P. expansum in apple tissues and liquid culture at 12 h. In total, 3168 and 1318 up-regulated and down-regulated genes were identified. Among them, genes regarding the biosynthesis of substances such as ergosterol, organic acid, cell wall degrading enzymes, and patulin were induced in expression. Pathways were activated, including autophagy, the mitogen-activated protein kinase, and pectin degradation. Our findings provide insights into the lifestyle and the mechanisms of P. expansum invading apple fruits.

Mechanism of cystine stone growth revealed by ultrastructural observation using scanning electron microscopy

Mechanism of cystine stone growth revealed by ultrastructural observation using scanning electron microscopy

The genetic basis and potential molecular mechanism of yellow-albino northern snakehead (Channa argus).

Body colour is an important economic trait for commercial fishes. Recently, a new colour morph displaying market-favoured yellow skin (termed as yellow-mutant, YM) of northern snakehead (Channa argus) was discovered in China. We confirmed that YM snakehead is an albino with complete loss of melanin in the skin and eyes by histological and ultrastructural observations, and inherited as a recessive Mendelian trait. By applying genomic analysis approaches, in combination with gene knockdown and rescue experiments, we suggested a non-sense mutation in slc45a2 (c.383G > A) is the causation for the YM snakehead. Notably, significantly higher levels of key melanogenesis genes (tyr, tyrp1, dct and pmel) and phospho-MITF protein were detected in YM snakehead than those in wild-type individuals, and the underlying mechanism was further investigated by comparative transcriptomic analysis. Results revealed that differential expressed genes involved in pathways like MAPK, WNT and calcium signalling were significantly induced in YM snakehead, which might account for the increased amount of melanogenesis elements, and presumably be stimulated by fibroblast-derived melanogenic factors in a paracrine manner. Our study clarified the genetic basis of colour variation in C. argus and provided the preliminary clue indicating the potential involvement of fibroblasts in pigmentation in fish.