Search Results (131)

The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex is a conserved transcriptional coactivator that coordinates histone modifications and transcriptional regulation in eukaryotes. In Cryptococcus neoformans, SAGA governs key virulence traits, yet the roles of several core scaffold subunits remain undefined. Here, we characterize the functional roles of Spt7, a core SAGA component, in C. neoformans. Comparative genomics revealed that C. neoformans Spt7 retains conserved histone fold and bromodomain motifs. Deletion of SPT7 produced pleiotropic phenotypes, including defective melanization and capsule formation, impaired titan cell development, and heightened sensitivity to thermal, metal, antifungal, and cell wall stresses. The spt7Δ mutant exhibited strong sensitivity to the echinocandin micafungin, implicating Spt7 in maintaining cell wall integrity. The spt7Δ mutant was avirulent in a murine inhalation model. At the chromatin level, SPT7 deletion disrupted SAGA-dependent histone post-translational modifications, increasing H2B ubiquitination while reducing H3K14ac and H3K18ac levels. Proteomic profiling revealed reduced abundance of ribosomal, mitochondrial, and translational proteins and upregulation of lipid metabolic and secretory pathway components. Collectively, our findings establish Spt7 as a central integrator of SAGA-mediated chromatin regulation, proteomic balance, and virulence in C. neoformans and highlight the SAGA core as a potential antifungal target. Full article

Biological control using beneficial microbes offers a sustainable alternative to chemical fungicides for managing postharvest diseases. This study reports the isolation and characterization of Bacillus amyloliquefaciens AsL-1 from the latex of Alstonia scholaris (L.) R. Br., unconventional ecological niche. The cell-free supernatant (CFS) of AsL-1 showed strong antifungal activity, inhibiting the growth of Colletotrichum musae (48.89 ± 0.57%), Glomerella cingulata (52.22 ± 0.00%), Fusarium graminearum (47.78 ± 0.57%), and Colletotrichum gloeosporioides (47.78 ± 0.00%) in vitro. Microscopy revealed that the CFS disrupted fungal development by blocking conidial germination and appressorium formation, and in C. gloeosporioides caused melanization defects linked to reduced virulence. In vivo tests on mango fruit confirmed that AsL-1 significantly decreased anthracnose lesion size and disease incidence. Protein analyses (SDS-PAGE, gel overlay, and LC-MS/MS) identified two antifungal proteins (24 and 16 kDa), corresponding to β-1,3-1,4-glucanase and flagellin. The detected β-1,3-1,4-glucanase activity indicates its role in degrading fungal cell walls and interfering with melanin biosynthesis pathways essential for pathogenicity. Overall, these findings highlight B. amyloliquefaciens AsL-1 as a promising protein-based biocontrol agent and show that latex-associated microbes may serve as valuable sources of new antifungal strategies. Full article

Uterine angiomyolipoma (AML) is an exceptionally rare mesenchymal tumor of the perivascular epithelioid cell tumor (PEComa) family. Most cases are benign and exhibit a triphasic histologic pattern. Although extragenital PEComas typically show strong, diffuse HMB-45 reactivity, uterine AMLs/PEComas often exhibit weak or negative staining, thereby introducing diagnostic uncertainty. We describe a rare case of uterine AML with diffuse nuclear atypia in a postmenopausal woman, which mimicked a degenerative leiomyoma or leiomyosarcoma. A 49-year-old postmenopausal woman presented with the rapid enlargement of a uterine mass that had been followed for four years as a presumed leiomyoma. Imaging revealed a well-circumscribed uterine mass with heterogeneous enhancement, cystic degeneration, and restricted diffusion on MRI. A total hysterectomy was performed. Grossly, the tumor measured 8 cm. Microscopically, it consisted of pleomorphic epithelioid cells (70%), mature adipose tissue (20%), and thick-walled vessels. Immunohistochemistry revealed diffuse smooth muscle actin (SMA) positivity, while Human Melanoma Black (HMB)-45 and Melan-A were negative. Only one mitosis per 50 HPF was identified, with no atypical mitoses or necrosis, and the Ki-67 index was low (<5%). The patient has remained disease-free for 56 months post-surgery. This case represents the first documented HMB-45-negative uterine angiomyolipoma with diffuse nuclear atypia, characterized by a low mitotic index, low Ki-67 proliferation rate, and a benign 56-month follow-up. It broadens the morphologic spectrum of uterine AML, demonstrating that diffuse nuclear atypia can occur in HMB-45-negative tumors with benign behavior, and that atypia alone should not be interpreted as evidence of malignancy. Recognition of this rare variant is essential to avoid misdiagnosing it as leiomyosarcoma. Full article

Cutaneous melanoma remains one of the most aggressive tumors, yet the role innate immunity plays in its progression remains poorly understood. Effector elements with high regulatory potential, capable of both promoting and inhibiting tumor growth—mast cells (MCs), are of particular interest. This includes quantitatively characterizing the interactions between tryptase-positive mast cells (MCs) with atypical Melanin—A⁺ cells and describing their spatial phenotype, in relation to the stage of cutaneous melanoma. A retrospective analysis was carried out on samples retrieved from 128 patients with cutaneous melanoma (AJCC 8th edition: IA–IIID). Histological analysis, histochemistry (toluidine blue, Giemsa), and diplex /multiplex IHC for tryptase and Melan-A were performed; as well as Fluorescence imaging, 3D reconstructions and quantitative mapping in QuPath v 0.6.0. Proximity was assessed by the nucleus-to-nucleus distance: <10 μm (contact), 10–20 μm (paracrine zone), >20 μm (out of interaction). The relative amount of MCs in the intratumoral zone was lower than in the intact dermis, with a simultaneous increase in their absolute density per mm² in the melanoma microenvironment, maximum in the peritumoral area and most pronounced at stage II. Three types of interactions were identified: (i) juxtaposition without secretion, (ii) degranulation of MCs directed to tumor cells, (iii) melanosecretion of Melanin—A⁺ cells directed towards MCs, followed by phagocytosis of melanocores. An inverse intratumoral connection between the number of MCs and the number of Melanin—A⁺ cells was noted; MCs with elongated forms, extensive contacts and polarized tryptase secretion, including granule localization near/at the nuclei of adjacent cells, were frequently observed. The obtained data indicate stage-region-dependent bidirectional cross-talk between melanin and MCs, forming tissue spatial signals, potentially useful as biomarkers and targets for personalized therapy. Full article

Hemocytes (insect blood cells) consist of several morphological types and perform a variety of physiological processes, including immune responses. However, we do not know how many cell types are functionally differentiated in hemocytes or how they perform independent physiological processes. To address this fundamental question, we analyzed hemocyte transcripts with a single-cell RNA-sequencing (scRNA-Seq) technique. The hemocytes were collected from larvae of a lepidopteran insect, Spodoptera exigua, in which four different hemocyte types were morphologically recognized. scRNA-Seq discriminated 24 hemocyte clusters based on the transcripts of each cell. The clusters were separated into seven functional groups predicted from the top three highly expressed and annotated genes in each cluster: active protein synthesis (12 clusters), apoptosis (5 clusters), melanization (2 clusters), modulating cell shape (6 clusters), antimicrobial peptide production (9 clusters), calcium homeostasis (8 clusters), and cell repairing (1 cluster). Signal components of Toll/IMD immune pathways were variably expressed among the clusters. Biosynthetic genes associated with oxylipin immune mediators were specifically expressed among the clusters. Immune effectors such as melanization and apoptosis were expressed in specific hemocyte clusters. Specifically expressed genes that discriminate hemocyte types were used to develop fluorescence in situ hybridization (FISH) markers. In addition, five new hemocyte groups, which were not among the four known hemocyte types in the transcript profile, were identified and discriminated with their specific FISH markers. The hemocyte clusters underwent dynamic changes upon immune challenge. A trajectory analysis using the transcriptome suggests at least three different hemocyte differentiation pathways. These results indicate that the hemocytes of S. exigua are functionally highly differentiated and exhibit a dynamic transition in response to environmental changes. Full article

The codling moth Cydia pomonella (L.) represents a substantial threat to the apple tree industry, with its cellular content being agronomically vital as it serves as the final immunological and toxicological barrier of the pest. Key hemocyte types identified in the hemolymph include plasmatocytes, granulocytes, spherulocytes, and oenocytoids. Hemolymph samples were in vitro suspended in various salt buffers (physiological saline, phosphate saline buffer (PBS) and Galleria mellonella anticoagulant buffer) to determine the most suitable one for agricultural monitoring purposes. The pH influenced the total hemocyte counts and the type of cells that adhered to the slides. PBS (pH 6.5) was found to be optimal for such studies due to its high levels of cellular attachment, cell viability, absence of melanization, and cellular degeneration effects. The supplementation of 5% CaCl₂ to PBS did not enhance the functional utility of the buffer. The in vivo bacterial challenge of larval hemolymph with 4 × 10⁸ sp/mL Bacillus subtilis provided complete clearance from the microbial invader within 30 min. Hemocytes released antimicrobial lysozyme as part of their innate immune responses. Hemocytic examination of larvae as an agricultural practice is strongly recommended for baseline insecticide resistance avoidance and predictive efficiency of integrated pest management in the apple farm. Full article

Carnosic acid (CA) is a phenolic diterpene with high antioxidant activity that supports its radioprotective capacity. This study aims to determine whether the radiosensitizing effect of CA established in B16F10 melanoma cells also occurs in other melanin-producing cells. Cell survival analysis, apoptosis, intracellular glutathione levels, and cell cycle progression were evaluated by comparing radiosensitive cells (PNT2) with radioresistant melanin-producing cells (MELAN A, SK-MEL-1, and B16F10). In PNT2 cells, CA exhibited radioprotective capacity, with 100% cell survival after exposure to 20 Gy of X-rays (p < 0.001), decreasing apoptosis (p < 0.001) and increasing the GSH/GSSG ratio (p < 0.01), without significant modification in cell cycle progression. However, CA administration to irradiated cells failed to exert radioprotection in MELAN A and SK-MEL-1 cells, and even doubled cell death in B16F10 cells (p < 0.001). Specifically, CA did not alter apoptosis or prevent the decrease in GSH/GSSG ratio in MELAN A and SK-MEL-1 cells, while it intensified radiation-induced cell cycle disruptions in all melanin-producing cells. All of these led to a loss of radioprotective capacity in the melanin-producing cells (MELAN A and SK-MEL-1) and even induced a radiosensitizing effect in B16F10 cells. Understanding the mechanisms of action of substances such as CA could promote new applications that protect healthy cells and exclusively damage neoplastic cells when both are present within the same irradiated volume in cancer patients requiring radiotherapy. Full article

Verticillium wilt, caused by Verticillium dahliae, severely threatens various crops and trees worldwide. This study aimed to characterize the function of a CUE (coupling of ubiquitin conjugation to endoplasmic reticulum (ER) degradation)-domain-containing protein, VdCUE, in V. dahliae, which exhibits sequence divergence between the defoliating strain XJ592 and the non-defoliating strain XJ511. We generated ∆VdCUE-knockout mutants and evaluated their phenotypes in growth and virulence. Functional analyses included verifying the signal peptide activity of VdCUE, testing its ability to induce cell death or inhibit BAX-induced cell death in Nicotiana benthamiana leaves, and identifying host targets via yeast two-hybrid screening. The ∆VdCUE mutants showed reduced formation of melanized microsclerotia but no other obvious growth defects. Cotton plants infected with the ∆VdCUE mutants exhibited a significantly lower disease index and defoliation rate. VdCUE was confirmed to be secreted via a functional signal peptide, but it neither triggered cell death nor inhibited BAX-induced cell death. Three putative host targets were identified and supported by AI-based three-dimensional structural modeling, including tRNA-specific 2-thiouridylase, peptidyl-prolyl cis-trans isomerase, and 40S ribosomal protein, which may mediate VdCUE-dependent virulence regulation. These findings reveal VdCUE as a key virulence factor in V. dahliae, contributing to our understanding of its pathogenic mechanism. Full article

Background: Nested melanoma is a rare subtype of superficial spreading melanoma. Due to its typical histology, characterized by the predominance of large melanocytic nests in an extensive horizontal spread, it is challenging to distinguish it from other benign nested melanocytic lesions. There is a need to identify additional histopathological parameters that can support the diagnosis of nested melanoma. Methods: In this retrospective case-control study, we analyzed immunohistochemical staining for PRAME in 10 cases of superficial spreading melanoma with prominent nests and 26 nested melanomas. Dysplastic melanocytic nevi were used as the control group. Results: We found a diffuse PRAME positivity (>75% of melanocytes) in 60% of superficial spreading melanoma with prominent nests and 19% of nested melanoma cases, whereas the control group showed no diffuse PRAME positivity. Furthermore, using Melan A immunohistochemistry, we found an absence of pagetoid spread in 31% of nested melanoma and single cells in suprabasal epidermal layers in 69% of cases. All cases with no pagetoid spread were PRAME negative, whereas 28% of cases with a mild pagetoid spread demonstrated diffuse PRAME positivity. Conclusions: We found lower PRAME positivity in nested melanoma compared to superficial spreading melanoma with prominent nests. Particularly in cases without pagetoid intraepidermal spread of melanocytes, negative PRAME staining does not rule out the possibility of nested melanoma. The diagnosis should be made based on typical histomorphological and clinical criteria. Full article

The aggressiveness of oral melanoma can be related to several mutations that occur during development. Based on the knowledge of the role of transcription factors of the SOX family in other neoplastic types, it is necessary to understand their behavior in oral melanomas. In this work, the expression of SOX2, SOX3, and SOX10 and its relationship with the proliferative index and histological aspects indicative of aggressiveness in canine oral melanomas were evaluated. Thirty tumors were histologically reviewed and the expression of Melan-A, SOX2, SOX3, SOX10, and Ki67 in these tumors were determined. All tumors presented histomorphological characteristics compatible with malignant tumors and immunopositivity for Melan-A. The expression of SOX2, SOX3, and SOX10 was observed in 7/30 (23.3%), 6/30 (20%), and 23/30 (76.6%) of the cases, respectively. Among the analyzed markers, the relationship between the loss of SOX3 expression in tumors with higher proliferative rates was highlighted. An inverse correlation was also observed between the expression cytoplasmic SOX10 and nuclear SOX10, suggesting a change in the location of this protein in oral melanomas. Among the SOX family proteins studied, the SOX3 protein plays a role in the regulation of cell proliferation in oral melanomas, and it is suggested that the SOX2 and SOX10 proteins are constitutively expressed in these neoplasms, without a determining role for aggressiveness. New studies of this gene transcription pathway may assist in possible prognostic and predictive determinations of the SOX3 protein in oral canine melanoma. Full article

The pupal endoparasitoid B. lasus injects venom into its host G. mellonella during oviposition, yet knowledge about the venom remains limited. This study explores how parasitism and venom from B. lasus impair the host’s cellular and humoral immunity. At 12–24 h post-parasitization, parasitized G. mellonella pupae had significantly lower total hemocyte counts and also exhibited higher mortality than non-parasitized controls. The proportion of plasmatocytes decreased, while the percentage of granulocytes increased. Parasitism also suppressed in vitro hemocyte spreading, with no significant difference in melanization between parasitized and control groups. Venom treatment significantly inhibited hemocyte spreading and increased cell mortality. Notably, venom-exposed hemocytes showed elevated reactive oxygen species levels and calcium ion concentrations, along with a significant decrease in mitochondrial membrane potential, while caspase 3 activity remained unchanged. These results suggest that both B. lasus parasitism and its venom suppress the cellular immunity of G. mellonella and have strong hemocytotoxic effects. The findings emphasize the role of venom in disrupting host defenses for the development of parasitoid offspring. Full article

Paracoccidioides brasiliensis is a thermally dimorphic fungal pathogen and the main etiological agent of paracoccidioidomycosis (PCM), a neglected systemic mycosis endemic in Latin America. The virulence of P. brasiliensis is closely associated with its capacity to survive under hostile host conditions, including acidic environments. In this study, we demonstrate that acidic pH induces melanization in P. brasiliensis, modulates its cell wall composition, and alters the interaction with macrophages. Cultivation at acidic pH resulted in reduced fungal growth without compromising viability and triggered increased production of melanin-like pigments, as confirmed by enhanced laccase activity and upregulation of genes in the DHN-melanin biosynthetic pathway. Additionally, growth under acidic pH induced significant remodeling of the fungal cell wall, leading to increased chitin on the cell wall surface and reduced mannan content, while β-glucan levels remained unchanged. These modifications correlated with decreased viability to Congo Red, suggesting altered cell wall stability. Importantly, P. brasiliensis grown under acidic conditions exhibited reduced phagocytosis by RAW 264.7 macrophages, along with changes in nitric oxide and cytokine production, indicating potential mechanisms of immune evasion. Collectively, our findings suggest that environmental acidification promotes fungal adaptations that enhance survival and modulate host–pathogen interactions, contributing to P. brasiliensis virulence. Understanding how acidic pH regulates these processes provides new insights into the pathobiology of PCM and may contribute to understanding the mechanisms of fungal immune evasion. Full article

Gynecologic perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms characterized by the co-expression of melanocytic markers (HMB-45 and Melan-A) and smooth muscle markers (SMA, desmin, and caldesmon). The uterus is the most common organ affected, with approximately 110 cases reported worldwide, while occurrences in the cervix, vagina, ovary, and other gynecologic locations are exceptionally rare. These tumors typically present with nonspecific symptoms such as abnormal uterine bleeding and pelvic pain, often mimicking other uterine neoplasms. Histopathologically, PEComas exhibit epithelioid and spindle cell morphology with variable nuclear atypia, mitotic activity, and characteristic immunohistochemical profiles. Although most PEComas behave benignly, a subset demonstrates malignant potential, associated with larger tumor sizes, an increased mitotic index, necrosis, and vascular invasion; however, standardized diagnostic criteria remain scarce. Molecular alterations frequently involve the mTOR signaling pathway through tuberous sclerosis complex (TSC) 1 and TSC2 gene mutations, offering potential targets for therapy. Surgical resection with clear margins remains the cornerstone of treatment. For advanced or metastatic cases, mTOR inhibitors have shown promising efficacy, whereas the role of radiotherapy remains uncertain. This review aims to synthesize current knowledge regarding the epidemiology, clinical presentation, histologic features, malignant potential, and treatment of uterine PEComas, emphasizing the importance of accurate histopathological classification and molecular profiling to guide individualized therapeutic strategies. Full article

Introduction: Among uterine tumors resembling ovarian sex cord tumors (UTROSCTs), it has been suggested that GREB1-rearranged cases are biologically distinct from ESR1-rearranged cases and might be considered as a separate entity. Objectives: The aim of this systematic review was to assess the difference between GREB1- and ESR1-rearranged UTROSCTs with regard to several clinico-pathological parameters. Methods: Three electronic databases were searched from their inception to February 2025 for all studies assessing the presence of GREB1 and ESR1 rearrangements in UTROSCTs. Exclusion criteria comprised overlapping patient data, case reports, and reviews. Statistical analysis was performed to compare clinicopathological variables between GREB1- and ESR1-rearranged UTROSCTs. Dichotomous variables were compared by using Fisher’s exact test; continuous variables were compared by using Student’s t-test. A p-value < 0.05 was considered significant. Results: Six studies with 88 molecularly classified UTROSCTs were included. A total of 36 cases were GREB1-rearranged, and 52 cases were ESR1-rearranged. GREB1-rearranged UTROSCTs showed a significantly older age (p < 0.001), larger tumor size (p = 0.002), less common submucosal/polypoid growth (p = 0.005), higher mitotic index (p = 0.010), more common LVSI (p = 0.049), and higher likelihood to undergo hysterectomy (p = 0.008) compared to ESR1-rearranged cases. No significant differences were detected with regard to margins, cytological atypia, necrosis, retiform pattern, and rhabdoid cells. No significant differences were found in the immunohistochemical expression of any of the assessed markers (wide-spectrum cytokeratins, α-inhibin, calretinin, WT1, CD10, CD56, CD99, smooth muscle actin, desmin, h-caldesmon, Melan-A/MART1, SF1, or Ki67). GREB1-rearranged UTROSCTs showed significantly lower disease-free survival compared to ESR1-rearranged UTROSTCs (p = 0.049). Conclusions: In conclusion, GREB1-rearranged UTROSCTs occur at an older age, are less likely to display a submucosal/polypoid growth, and exhibit larger size, a higher mitotic index, more common lymphovascular space invasion, and lower disease-free survival compared to ESR1-rearranged UTROSCTs. Nonetheless, the similar immunophenotype suggests that they belong to the same tumor family. Further studies are necessary to confirm this point. Full article

Uterine tumors resembling ovarian sex-cord tumors (UTROSCTs) are among the rarest types of uterine tumors. Diagnosis of a UTROSCT is often challenging. Imaging techniques such as ultrasound and MRI are limited in distinguishing UTROSCTs as their appearance is usually suggestive of uterine leiomyoma or adenomyosis. Additionally, the value of a preoperative biopsy remains uncertain due to the heterogeneous composition of the tumor and the inadequacy of limited samplings. We present a rare case of UTROSCT in a 59-year-old woman and we have performed a narrative review of the literature on PubMed, Scopus, and Web of Science from 2000 to June 2024, identifying 133 cases. According to our review, at histological exam UTROSCTs are mainly composed of cells resembling ovarian sex-cord elements which are arranged in cords or trabeculae, typically with a mild cytologic atypia. The most expressed sex-cord differentiation markers include inhibin, calretinin, melan A, CD56, CD99, SF1, WT1, CD10, and FOXL2. For women who have completed their reproductive plans, a total hysterectomy with adnexectomy is an adequate treatment for tumors confined to the uterus. For younger patients who wish to preserve fertility, tumorectomy via hysteroscopy or laparoscopy is the preferred treatment option and the recurrence rates range from 5% to 30%. Treatments for recurrent disease include surgery, chemotherapy, and radiation therapy, often used in combination. Advancements in molecular profiling and immunohistochemistry will improve our ability to diagnose and manage this tumor. Such investigations will enhance prognostic stratification, facilitating more accurate predictions of biological behavior and recurrence risk. Full article