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4.
Heliyon ; 10(16): e36620, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39258203

RESUMO

Due to sanctions, more Chinese high-tech SMEs are turning to rent AI computing power through cloud service providers. Therefore, it is necessary to give a variety of suggestions for China's high-tech SMEs to better develop AI applications through computing power leasing. Because traditional theories are difficult to explain this new technology adoption behavior, this research combines and extends TTF and UTAUT2 theories to take an empirical research. A total of 387 questionnaires were received, of which incomplete questionnaires and invalid questionnaires were issued, leaving 281 valid questionnaires. The results indicate that SME innovativeness, perceived risk, performance expectancy, price value and task technology fit are all significantly related to usage, whereas task technology fit moderates the other relationships significantly. Results give a variety of suggestions for China's high-tech SMEs to better develop AI applications through computing power leasing in the context of sanctions. This study not only suggests ways to increase the competitiveness of SMEs by optimizing leasing services but also give directions in investors' investment decisions. The findings are also applicable to the large-scale application of China's domestic AI chips in computing power leasing scenarios in the future.

5.
Arthroscopy ; 2024 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-39128679

RESUMO

PURPOSE: To enhance the understanding of histologic healing after repairing medial meniscal posterior root tears (MMPRTs) at an early stage, utilizing a goat model. METHODS: Eighteen adult goats, totaling 36 knee joints, were allocated into 3 groups (n = 12): sham group (Sham), root tear group (RT), and root tear with transosseous suture group (RTS). At 12- and 24-week intervals postsurgery, all the knees were harvested for imaging, macroscopic, histologic, and biomechanical assessments. RESULTS: The intact root served as a meniscus-bone interface that connected the tibial and circular fibers of the meniscus with a bony insertion and a root-meniscus transition. A direct fibrous connection was displayed at the bony insertion proximal to the synovium in the RTS group, while the remaining regions of the root displayed indirect fibrous healing. The healing in the RT group was disjointed and reminiscent of scar tissue. The RTS group exhibited a more pronounced coronal extrusion compared to the Sham group (0.42 ± 0.09 vs 0.19 ± 0.02, P = .0012) but was improved relative to that of the RT group (0.49 ± 0.02, P = .0028). The failure load and stiffness of the RTS group were notably higher than those of the RT group, with a strength of 42.67% and a stiffness of 83.75% of the intact root. All the samples ruptured at the root-meniscus transitions. CONCLUSIONS: The incomplete healing may be attributed to the histologic factors underlying the low healing rate and persistent medial meniscal extrusion. Notably, the region attached to the posterior cruciate ligament exhibited superior healing compared to other regions of the bony insertion in the repaired group. Conversely, the root-meniscus transition displayed discontinuity, representing a mechanical weakness in the healing process. CLINICAL RELEVANCE: Modifications of bone tunnel positioning and suture placement could be undertaken in subsequent studies to enhance the healing of the root-meniscus transition.

6.
Zhonghua Nan Ke Xue ; 30(2): 180-183, 2024 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-39177354

RESUMO

Pyroptosis, as a new programmed death mode, plays an important role in the development and progression of prostate cancer, and the drugs targeting the pyroptosis pathway, as a new therapeutic strategy, may produce a significant influence on the treatment of prostate cancer . However, the precise mechanism of cellular pyroptosis remains unclear, necessitating further investigation. This paper presents a summary of the role of cellular pyroptosis in prostate cancer over recent years. It includes a discussion of the mechanism of pyroptosis, its role in prostate cancer development, and its clinical applications. This will provide clinicians with a new strategy for treatment and drug development.


Assuntos
Progressão da Doença , Neoplasias da Próstata , Piroptose , Humanos , Neoplasias da Próstata/patologia , Masculino
7.
Huan Jing Ke Xue ; 45(6): 3661-3670, 2024 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-38897785

RESUMO

The impact of microplastics (MPs) as a new type of pollutant on water pollution has become a research hotspot. To explore the response relationship between the abundance of MPs and nitrogen metabolism function in a freshwater environment, Lake Ulansuhai was used as the research object; the abundance of MPs in the water was detected using a Zeiss microscope, and the distribution characteristics of nitrogen metabolism functional bacteria and functional genes in the water were analyzed using metagenomics sequencing. The correlation analysis method was used to explore the relationship between the abundance of MPs and nitrogen metabolism functional microorganisms and nitrogen metabolism functional genes. The results showed that the presence of MPs in freshwater environments had a higher impact on Cyanobacteria and Firmicutes as the dominant phyla, and the presence of MPs promoted their enrichment and growth. Among the dominant bacterial genera, MPs promoted the growth of Mycobacterium and inhibited Candidatus_Planktopila more significantly, further indicating that in freshwater environments, MPs affected normal nitrogen metabolism by affecting microbial communities, and pathways such as carbon and nitrogen fixation and denitrification were important pathways for MPs to affect nitrogen metabolism. From the perspective of nitrogen metabolism functional genes, it was found that the abundance of MPs significantly affected some functional genes during nitrification (pmoA-amoA, pmoB-amoB, and pmoC-amoC), denitrification (nirK and napA), and dissimilatory nitrate reduction (nrfA) processes (P < 0.05). Moreover, the influence of MPs abundance on different functional genes in the same pathway of nitrogen metabolism varied, making the impact of MPs on aquatic environments very complex; thus, its harm to the water environment cannot be underestimated.


Assuntos
Bactérias , Microplásticos , Nitrogênio , Poluentes Químicos da Água , Nitrogênio/metabolismo , Poluentes Químicos da Água/metabolismo , Bactérias/metabolismo , Bactérias/genética , Bactérias/classificação , Microbiologia da Água , Cianobactérias/metabolismo , Cianobactérias/genética , Lagos/microbiologia , China , Água Doce , Monitoramento Ambiental
8.
Huan Jing Ke Xue ; 45(5): 3088-3097, 2024 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-38629569

RESUMO

Mulching to conserve moisture has become an important agronomic practice in saline soil cultivation, and the effects of the dual stress of salinity and microplastics on soil microbes are receiving increasing attention. In order to investigate the effect of polyethylene microplastics on the microbial community of salinized soils, this study investigated the effects of different types (chloride and sulphate) and concentrations (weak, medium, and strong) of polyethylene (PE) microplastics (1% and 4% of the dry weight mass of the soil sample) on the soil microbial community by simulating microplastic contamination in salinized soil environments indoors. The results showed that:PE microplastics reduced the diversity and abundance of microbial communities in salinized soils and were more strongly affected by sulphate saline soil treatments. The relative abundance of each group of bacteria was more strongly changed in the sulphate saline soil treatment than in the chloride saline soil treatment. At the phylum level, the relative abundance of Proteobacteria was positively correlated with the abundance of fugitive PE microplastics, whereas the relative abundances of Bacteroidota, Actinobacteriota, and Acidobacteria were negatively correlated with the abundance of fugitive PE microplastics. At the family level, the relative abundances of Flavobacteriaceae, Alcanivoracaceae, Halomonadaceae, and Sphingomonasceae increased with increasing abundance of PE microplastics. The KEGG metabolic pathway prediction showed that the relative abundance of microbial metabolism and genetic information functions were reduced by the presence of PE microplastics, and the inhibition of metabolic functions was stronger in sulphate saline soils than in chloride saline soils, whereas the inhibition of genetic information functions was weaker than that in chloride saline soils. The secondary metabolic pathways of amino acid metabolism, carbohydrate metabolism, and energy metabolism were inhibited. It was hypothesized that the reduction in metabolic functions may have been caused by the reduced relative abundance of the above-mentioned secondary metabolic pathways. This study may provide a theoretical basis for the study of the effects of microplastics and salinization on the soil environment under the dual pollution conditions.


Assuntos
Microplásticos , Polietileno , Plásticos , Solo , Cloretos , Halogênios , Sulfatos , Microbiologia do Solo
9.
iScience ; 27(5): 109681, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38680664

RESUMO

Pannexins are large-pore ion channels expressed throughout the mammalian brain that participate in various neuropathologies; however, their physiological roles remain obscure. Here, we report that pannexin1 channels (Panx1) can be synaptically activated under physiological recording conditions in rodent acute hippocampal slices. Specifically, NMDA receptor (NMDAR)-mediated responses at the mossy fiber to CA3 pyramidal cell synapse were followed by a slow postsynaptic inward current that could activate CA3 pyramidal cells but was absent in Panx1 knockout mice. Immunoelectron microscopy revealed that Panx1 was localized near the postsynaptic density. Further, Panx1-mediated currents were potentiated by metabotropic receptors and bidirectionally modulated by burst-timing-dependent plasticity of NMDAR-mediated transmission. Lastly, Panx1 channels were preferentially recruited when NMDAR activation enters a supralinear regime, resulting in temporally delayed burst-firing. Thus, Panx1 can contribute to synaptic amplification and broadening the temporal associativity window for co-activated pyramidal cells, thereby supporting the auto-associative functions of the CA3 region.

10.
Dev Cell ; 59(11): 1410-1424.e4, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38593803

RESUMO

Endoplasmic reticulum exit sites (ERESs) are tubular outgrowths of endoplasmic reticulum that serve as the earliest station for protein sorting and export into the secretory pathway. How these structures respond to different cellular conditions remains unclear. Here, we report that ERESs undergo lysosome-dependent microautophagy when Ca2+ is released by lysosomes in response to nutrient stressors such as mTOR inhibition or amino acid starvation in mammalian cells. Targeting and uptake of ERESs into lysosomes were observed by super-resolution live-cell imaging and focus ion beam scanning electron microscopy (FIB-SEM). The mechanism was ESCRT dependent and required ubiquitinated SEC31, ALG2, and ALIX, with a knockout of ALG2 or function-blocking mutations of ALIX preventing engulfment of ERESs by lysosomes. In vitro, reconstitution of the pathway was possible using lysosomal lipid-mimicking giant unilamellar vesicles and purified recombinant components. Together, these findings demonstrate a pathway of lysosome-dependent ERES microautophagy mediated by COPII, ALG2, and ESCRTS induced by nutrient stress.


Assuntos
Vesículas Revestidas pelo Complexo de Proteína do Envoltório , Proteínas de Ligação ao Cálcio , Retículo Endoplasmático , Complexos Endossomais de Distribuição Requeridos para Transporte , Lisossomos , Microautofagia , Proteínas de Transporte Vesicular , Lisossomos/metabolismo , Retículo Endoplasmático/metabolismo , Humanos , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Transporte Proteico , Células HeLa , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genética , Autofagia/fisiologia , Serina-Treonina Quinases TOR/metabolismo , Cálcio/metabolismo
11.
J Adv Res ; 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38492734

RESUMO

INTRODUCTION: Our previous study showed that the abscisic acid receptor lanthionine synthetase C-like 2 (LanCL2) is a significant prognostic factor for overall survival in young glioblastoma patients. However, the role of LanCL2 in glioblastoma remains unclear yet. OBJECTIVES: This study aims to investigate the role of LanCL2 in regulating in-vitro cell invasion and in-vivo tumor progression of glioblastoma and its underlying mechanism. METHODS: Tyrosine 198 or 295 residue of LanCL2 was mutated using site-directed mutagenesis to block its phosphorylation. The role of LanCL2 in glioblastoma was investigated using transwell or 3D invasion assay, matrix degradation assay and intracranial xenograft model. RESULTS: This study showed that nuclear transport of LanCL2 was enhanced by overexpression of LanCL2 or its ligand abscisic acid in glioblastoma cells. Knockdown of LanCL2 suppressed migration, invasion and invadopodia formation of glioblastoma cells, whereas overexpression of wild-type LanCL2 enhanced them. Blocking of Tyr295 residue phosphorylation of LanCL2 impeded its nuclear transport, retarded glioblastoma cell motility and invadopodia formation, and deceased the phosphorylation of Cortactin and STAT3. c-Met was identified as the upstream tyrosine kinase of Tyr295 residue of LanCL2, and inhibition of c-Met markedly suppressed the nuclear transport of LanCL2. Moreover, overexpression of wild-type LanCL2 significantly promoted orthotopic tumor growth of glioblastoma in vivo and led to poor survival of mice with median survival time of 33.5 days, whereas Tyr295 mutation rescued it with median survival time of 49 days. CONCLUSION: Our findings suggested that Tyr295 phosphorylation is crucial to the activation and nuclear transport of LanCL2, as well as invadopodia formation and tumor progression of glioblastoma, providing the evidence of a novel signaling axis c-Met/LanCL2/STAT3/Cortactin and the first observation of the importance of Tyr295 phosphorylation to LanCL2.

12.
Arthrosc Sports Med Rehabil ; 6(2): 100881, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38328534

RESUMO

Purpose: To (1) evaluate the clinical and radiographic outcomes of patients with primary anterior cruciate ligament reconstruction (ACLR) with type II posterior lateral meniscus root tear (PLMRT) repair and (2) identify whether increased anterior tibial subluxation of the lateral compartment (ATSLC) and steeper posterior tibial slope (PTS) are associated with sagittal lateral meniscal extrusion (LME). Methods: Patients who underwent primary anatomic ACLR with concomitant type II PLMRTs using the all-inside side-to-side repair technique between November 2014 and September 2020 were identified. To be included, patients must have had a minimum of 2 years follow-up. All patients, including those with ATSLC and PTS and sagittal and coronal LME, were retrospectively reviewed clinically and radiologically. The patients were divided into 2 subgroups according to the occurrence of sagittal LME. Results: Forty patients were included in this study with a mean follow-up of 44 months (range, 24-94 months). In general, the postoperative parameters, including grade of pivot shift, side-to-side difference, ATSLC, Lysholm score, and International Knee Documentation Committee (IKDC) score, were significantly improved compared with the preoperative ones. However, postoperative sagittal LME was detected to be significantly larger than the preoperative one. Minimal clinically important difference (MCID) analysis for postoperative outcomes showed that the rate of patients who achieved MCID thresholds was 100% for Lysholm, 95% for IKDC, 42.50% for coronal LME, 62.50% for sagittal LME, 40% for ATSLC, and 100% for side-to-side difference. Further comparisons, where patients were divided into 2 subgroups according to the occurrence of sagittal LME, showed significant differences in PTS, ATSLC, and coronal LME. Conclusions: Clinical outcomes after type II PLMRT repair with primary ACLR were significantly improved, except for LME, at the 2-year postoperative follow-up. After repair of type II PLMRT injuries, the presence of sagittal LME was associated with increased PTS and ATSLC. Level of Evidence: Level III, retrospective cohort study.

14.
Eur J Med Res ; 28(1): 388, 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37770993

RESUMO

BACKGROUND: Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease predominantly affecting the axial skeleton. We aimed to describe the clinical characteristics of patients with non-radiographic axSpA (nr-axSpA) in China and compare the differences between adult- and juvenile-onset cases. METHODS: A cross-sectional study was conducted using data from 776 patients with nr-axSpA in the Clinical Characteristic and Outcome in Chinese Axial Spondyloarthritis (COCAS) study cohort. Patients were divided into two groups including the adult-onset group (n = 662) and the juvenile-onset group (n = 114) according to age at disease onset. Baseline demographics and clinical characteristics were compared between patients with adult-onset and juvenile-onset nr-axSpA. RESULTS: Overall, the male-to-female ratio was 1.26:1, the prevalence of HLA-B27 positivity was 72.2%, and the median age at disease onset of nr-axSpA was 22 years. Nearly 75% of nr-axSpA patients had peripheral arthritis in the disease course, and the prevalence of extra-articular manifestations was 10.4%. The juvenile-onset group contained a higher proportion of men (66.7% vs. 53.9%, P = 0.011) and a longer baseline disease duration (4.0 [4.0] vs. 1.6 [3.5], P < 0.001) than the adult-onset group. A family history of spondyloarthritis was more frequent in the juvenile-onset group than in the adult-onset group (23.7% vs. 15.4%, P = 0.028), but no significant difference in the prevalence of HLA-B27 positivity was observed between the two groups (P = 0.537). Regarding initial symptoms, peripheral arthritis occurred more often in patients with juvenile-onset nr-axSpA, whereas patients with adult-onset nr-axSpA presented more frequently with axial involvement. The prevalence of inflammatory back pain (IBP) was higher in the adult-onset group than in the juvenile-onset group (85.0% vs. 75.4%, P = 0.010), whereas the juvenile-onset group showed a higher prevalence of peripheral arthritis and enthesitis than the adult-onset group (67.5% vs. 48.5%, P < 0.001; 35.1% vs. 23.3%, P = 0.007, respectively). CONCLUSIONS: Compared with adult-onset nr-axSpA, juvenile-onset nr-axSpA was more common in men and those with a family history of spondyloarthritis. Juvenile-onset nr-axSpA presents with a "peripheral predominant" mode at disease onset and a higher frequency of peripheral arthritis and enthesitis during the disease course.


Assuntos
Espondiloartrite Axial não Radiográfica , Espondilartrite , Espondilite Anquilosante , Adulto , Feminino , Humanos , Masculino , Adulto Jovem , Estudos Transversais , Progressão da Doença , População do Leste Asiático , Antígeno HLA-B27/genética , Espondiloartrite Axial não Radiográfica/diagnóstico , Espondiloartrite Axial não Radiográfica/epidemiologia , Dor , Espondilartrite/epidemiologia , Espondilartrite/diagnóstico , Espondilite Anquilosante/diagnóstico , Espondilite Anquilosante/epidemiologia
15.
Sci Adv ; 9(37): eadi4147, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37703368

RESUMO

Mechanosensory corpuscles detect transient touch and vibration in the skin of vertebrates, enabling precise sensation of the physical environment. The corpuscle contains a mechanoreceptor afferent surrounded by lamellar cells (LCs), but corpuscular ultrastructure and the role of LCs in touch detection are unknown. We report the three-dimensional architecture of the avian Meissner (Grandry) corpuscle acquired using enhanced focused ion beam scanning electron microscopy and machine learning-based segmentation. The corpuscle comprises a stack of LCs interdigitated with terminal endings from two afferents. Simultaneous electrophysiological recordings from both cell types revealed that mechanosensitive LCs use calcium influx to trigger action potentials in the afferent and thus serve as physiological touch sensors in the skin. The elaborate architecture and bicellular sensory mechanism in the corpuscles, which comprises the afferents and LCs, create the capacity for nuanced encoding of the submodalities of touch.


Assuntos
Percepção do Tato , Tato , Animais , Pele , Potenciais de Ação , Cálcio
16.
World J Clin Cases ; 11(20): 4937-4943, 2023 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-37583990

RESUMO

BACKGROUND: Ischemic colitis (IC) is common, rising in incidence and associated with high mortality. Its presentation, disease behavior and severity vary widely, and there is significant heterogeneity in therapeutic strategies and prognosis. The common causes of IC include thromboembolism, hemodynamic insufficiency, iatrogenic factors and drug-induced. However, contrast-induced IC, especially isolated right colon ischemia is rarely reported. CASE SUMMARY: A 52-year-old man was admitted to the hospital due to intermittent chest distress accompanied by palpitation. Coronary angiography was performed using 60 mL of the iodinated contrast agent iohexol (Omnipaque 300), and revealed moderate stenosis of the left anterior descending artery and right coronary artery. At 3 h post-procedure, he complained of epigastric pain without fever, diarrhea and vomiting. Vital signs remained normal. An iodixanol-enhanced abdominal computed tomography (CT) scan revealed thickening, edema of the ascending and right transverse colonic wall and inflammatory exudate, without thrombus in mesenteric arteries and veins. Following 4 days of treatment with antibiotic and supportive management, the patient had a quick and excellent recovery with disappearance of abdominal pain, normalization of leucocyte count and a significant decrease in C reactive protein. There was no recurrence of abdominal pain during the patient's two-year follow-up. CONCLUSION: This case emphasizes that contrast-induced IC should be considered in the differential diagnosis of unexplained abdominal pain after a cardiovascular interventional procedure with the administration of contrast media. Timely imaging evaluation by CT and early diagnosis help to improve the prognosis of IC.

17.
Knee Surg Sports Traumatol Arthrosc ; 31(10): 4546-4550, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37308663

RESUMO

PURPOSE: There is currently no consensus on the optimal drilling direction of the fibular bone tunnel for anterior talofibular ligament (ATFL) reconstruction, and few studies have investigated the potential injury to the peroneus longus and brevis tendons and the possibility of fibular fractures during the drilling process. The aim of this study was to assess the potential risk of drilling the tunnel from different directions and determine the most appropriate tunnel direction. The hypothesis was that drilling the tunnel in the 45-degree direction would be the safest and most suitable for the fibular tunnel. METHODS: Forty-eight fibular tunnels were drilled on fresh ankle specimens using a K-wire guide and a 5.0 mm hollow drill. Three tunnel orientations were created, parallel to the sagittal plane of the long axis of the fibula and angled 30°, 45°, and 60° to the coronal plane. The length of the fibular tunnel and the distances from the outlet of the K-wire to the peroneus longus and brevis tendons were measured. The occurrence of a fibula fracture was also observed. RESULTS: The lengths of the bone tunnels in the three groups were 32.9 ± 6.1 mm (30°), 27.2 ± 4.4 mm (45°) and 23.6 ± 4.0 mm (60°). The length of the tunnel drilled at 30° was the longest when compared with that of the tunnels drilled at 45° and 60° (all p values < 0.05). The distances from the outlet of the K-wire to the peroneus longus tendon were 3.0 ± 3.8 mm (30°), 3.8 ± 3.2 mm (45°) and 5.3 ± 1.8 mm (60°), and the distances to the peroneus brevis tendon were 4.2 ± 4.0 mm (30°), 6.1 ± 3.8 mm (45°), 7.9 ± 3.5 mm (60°). In terms of protecting the peroneus longus and brevis tendons, drilling in the 60° direction was better than drilling in the 30° and 45° directions (all p values < 0.05). The risk of injury to the peroneal longus and brevis tendons was 62.5% (30°), 31.3% (45°), and 0% (60°). Although no fibular fractures were observed in any of the three directions, drilling the bone tunnel in the 60° direction disrupted the lateral cortex of the fibula. CONCLUSION: This study shows that drilling the tunnel in the 45° direction is less likely to cause injury to the peroneus longus and brevis tendons, while ensuring that the tunnel has a sufficient length and avoiding fracturing the distal fibula. Drilling a fibular bone tunnel in a 45° direction is safer and recommended for ATFL reconstruction.


Assuntos
Fíbula , Ligamentos Laterais do Tornozelo , Humanos , Fíbula/cirurgia , Ligamentos Laterais do Tornozelo/cirurgia , Articulação do Tornozelo/cirurgia , Tendões/cirurgia , Tornozelo
19.
Front Plant Sci ; 14: 1178245, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37235032

RESUMO

Introduction: Begonia L., one of the 10 largest plant genera, contains over 2,100 species, most of which have a very limited distribution range. Understanding the spatial genetic structure and distribution dynamics of a widespread species in this genus will contribute to clarifying the mechanism responsible for Begonia speciation. Methods: In this study, we used three chloroplast DNA markers (ndhF-rpl32, atpI-atpH, and ndhA intron), coupled with species distribution modeling (SDM), to investigate the population genetic structure and distribution dynamics of Begonia grandis Dryand., the species of Begonia with the widest distribution in China. Results: Thirty-five haplotypes from 44 populations clustered into two groups, and haplotype divergence began in the Pleistocene (1.75 Mya). High genetic diversity (H d = 0.894, H T = 0.910), strong genetic differentiation (F ST = 0.835), and significant phylogeographical structure (G ST/N ST = 0.848/0.917, P < 0.05) were observed. The distribution range of B. grandis migrated northwards after the last glacial maximum, but its core distribution area remained stable. Discussion: Combined, the observed spatial genetic patterns and SDM results identified the Yunnan-Guizhou Plateau, the Three Gorges region, and the Daba Mountains as potential refugia of B. grandis. BEAST-derived chronogram and haplotype network analysis do not support the Flora Reipublicae Popularis Sinicae and Flora of China for subspecies classification based on morphological characteristics. Our results support the hypothesis that population-level allopatric differentiation may be an important speciation process for the Begonia genus and a key contributor to its rich diversity.

20.
bioRxiv ; 2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37066170

RESUMO

Mechanosensory corpuscles detect transient touch and vibratory signals in the skin of vertebrates, enabling navigation, foraging, and precise manipulation of objects 1 . The corpuscle core comprises a terminal neurite of a mechanoreceptor afferent, the only known touch-sensing element within corpuscles, surrounded by terminal Schwann cells called lamellar cells (LCs) 2â€"4 . However, the precise corpuscular ultrastructure, and the role of LCs in touch detection are unknown. Here we used enhanced focused ion beam scanning electron microscopy and electron tomography to reveal the three-dimensional architecture of avian Meissner (Grandry) corpuscle 5 . We show that corpuscles contain a stack of LCs innervated by two afferents, which form large-area contacts with LCs. LCs form tether-like connections with the afferent membrane and contain dense core vesicles which release their content onto the afferent. Furthermore, by performing simultaneous electrophysiological recordings from both cell types, we show that mechanosensitive LCs use calcium influx to trigger action potential firing in the afferent and thus serve as physiological touch sensors in the skin. Our findings suggest a bi-cellular mechanism of touch detection, which comprises the afferent and LCs, likely enables corpuscles to encode the nuances of tactile stimuli.

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