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1.
Rapid Commun Mass Spectrom ; : e9184, 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34472672

RESUMO

RATIONALE: α-amanitin is a highly toxic peptide widely found in species of poisonous mushrooms. Matrix effect has been a major hinder for accurate determination of α-amanitin in plasma sample by LC-MS/MS. In this study, the strategy to eliminate matrix effect of α-amanitin with one step dilution approach after deproteinization was applied. METHODS: Rat plasma samples were processed by protein precipitation with methanol followed by a 9-fold dilution with pure water. The matrix effect value of α-amanitin was 19.7%-22.2% by protein precipitation and then changed to 87.5%-88.7% after dilution. α-amanitin and internal standard (roxithromycin) were analysed on an ACQUITY UPLC® BEH C18 (50 mm × 2.1 mm, 1.7 µm) column within 3.0 min by gradient elution. RESULTS: The linear ranges were 0.90-600 ng/mL with a correlation coefficient r > 0.9958. The lower limit of quantification (LLOQ) of 0.90 ng/mL was achieved using only 50 µL of rat plasma. The intra- and inter-day precisions for the analyte ranged from 3.2% to 7.5% and 3.1% to 7.1%, respectively, and the accuracy ranged from -5.3% to -8.0%. CONCLUSIONS: The matrix effect of α-amanitin was reduced by sample dilution after plasma deproteinization. A reliable LC-MS/MS method for the determination of α-amanitin in rat plasma was developed. This method was successfully applied for a toxicokinetic study of rats after intravenous injection of α-amanitin with subacute toxicity dose at 0.10 mg/kg.

2.
Front Cell Infect Microbiol ; 11: 691092, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34490138

RESUMO

Oral microbiota is constantly changing with the host state, whereas the oral microbiome of chronic erythematous candidiasis remains poorly understood. The aim of this study was to compare oral microbial signatures and functional profiling between chronic erythematous candidiasis and healthy subjects. Using shotgun metagenomic sequencing, we analyzed the microbiome in 12 chronic erythematous candidiasis, 12 healthy subjects, and 2 chronic erythematous candidiasis cured by antifungal therapy. We found that the salivary microbiota of chronic erythematous candidiasis was significantly different from that of healthy subjects. Among them, Rothia mucilaginosa and Streptococcus mitis were the most abundant disease-enriched species (Mann-Whitney U-test, P < 0.05). In addition, co-occurrence network analysis showed that C. albicans formed densely connected modules with oral bacterial species and was mainly positive connected to Streptococcus species. Furthermore, we investigated the functional potentials of the microbiome and identified a set of microbial marker genes associated with chronic erythematous candidiasis. Some of these genes enriching in chronic erythematous candidiasis are involved in eukaryotic ribosome, putative glutamine transport system, and cytochrome bc1 complex respiratory unit. Altogether, this study revealed the changes of oral microbial composition, the co-occurrence between C. albicans and oral bacteria, as well as the changes of microbial marker genes during chronic erythematous candidiasis, which provides evidence of oral microbiome as a target for the treatment and prevention of chronic erythematous candidiasis.

3.
BMC Infect Dis ; 21(1): 931, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34496794

RESUMO

BACKGROUND: To develop a machine learning-based CT radiomics model is critical for the accurate diagnosis of the rapid spreading coronavirus disease 2019 (COVID-19). METHODS: In this retrospective study, a total of 326 chest CT exams from 134 patients (63 confirmed COVID-19 patients and 71 non-COVID-19 patients) were collected from January 20 to February 8, 2020. A semi-automatic segmentation procedure was used to delineate the volume of interest (VOI), and radiomic features were extracted. The Support Vector Machine (SVM) model was built on the combination of 4 groups of features, including radiomic features, traditional radiological features, quantifying features, and clinical features. By repeating cross-validation procedure, the performance on the time-independent testing cohort was evaluated by the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity. RESULTS: For the SVM model built on the combination of 4 groups of features (integrated model), the per-exam AUC was 0.925 (95% CI 0.856 to 0.994) for differentiating COVID-19 on the testing cohort, and the sensitivity and specificity were 0.816 (95% CI 0.651 to 0.917) and 0.923 (95% CI 0.621 to 0.996), respectively. As for the SVM models built on radiomic features, radiological features, quantifying features, and clinical features, individually, the AUC on the testing cohort reached 0.765, 0.818, 0.607, and 0.739, respectively, significantly lower than the integrated model, except for the radiomic model. CONCLUSION: The machine learning-based CT radiomics models may accurately classify COVID-19, helping clinicians and radiologists to identify COVID-19 positive cases.

4.
Dev Cell ; 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34508658

RESUMO

Membrane contact between intracellular organelles is important in mediating organelle communication. However, the assembly of molecular machinery at membrane contact site and its internal organization correlating with its functional activity remain unclear. Here, we demonstrate that a gel-like condensation of Cidec, a crucial protein for obesity development by facilitating lipid droplet (LD) fusion, occurs at the LD-LD contact site (LDCS) through phase separation. The homomeric interaction between the multivalent N terminus of Cidec is sufficient to promote its phase separation both in vivo and in vitro. Interestingly, Cidec condensation at LDCSs generates highly plastic and lipid-permeable fusion plates that are geometrically constrained by donor LDs. In addition, Cidec condensates are distributed unevenly in the fusion plate generating stochastic sub-compartments that may represent unique lipid passageways during LD fusion. We have thus uncovered the organization and functional significance of geometry-constrained Cidec phase separation in mediating LD fusion and lipid homeostasis.

5.
J Nanobiotechnology ; 19(1): 275, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34503490

RESUMO

BACKGROUND: Skin injury and the resultant defects are common clinical problems, and usually lead to chronic skin ulcers and even life-threatening diseases. Copper, an essential trace element of human body, has been reported to promote the regeneration of skin by stimulating proliferation of endothelial cell and enhance angiogenesis. RESULTS: Herein, we have prepared a new donut-like metal-organic frameworks (MOF) of copper-nicotinic acid (CuNA) by a simple solvothermal reaction. The rough surface of CuNA is beneficial for loading/release basic fibroblast growth factor (bFGF). The CuNAs with/without bFGF are easily processed into a light-responsive composite hydrogel with GelMA, which not only show excellent mechanical properties, but also display superior biocompatibility, antibacterial ability and bioactivity. Moreover, in the in vivo full-thickness defect model of skin wound, the resultant CuNA-bFGF@GelMA hydrogels significantly accelerate the wound healing, by simultaneously inhibiting the inflammatory response, promoting the new blood vessels formation and the deposition of collagen and elastic fibers. CONCLUSIONS: Considering the superior biocompatibility, antibacterial ability and bioactivity, the CuNA and its composite light-responsive hydrogel system will be promising in the applications of skin and even other tissue regeneration.

6.
J Nanobiotechnology ; 19(1): 269, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34493305

RESUMO

BACKGROUND: Many patients suffer from implant loosening after the implantation of titanium alloy caused by immune response to the foreign bodies and this could inhibit the following osteogenesis, which could possibly give rise to aseptic loosening and poor osteointegration while there is currently no appropriate solution in clinical practice. Exosome (Exo) carrying miRNA has been proven to be a suitable nanocarrier for solving this problem. In this study, we explored whether exosomes overexpressing miR-181b (Exo-181b) could exert beneficial effect on promoting M2 macrophage polarization, thus inhibiting inflammation as well as promoting osteogenesis and elaborated the underlying mechanism in vitro. Furthermore, we aimed to find whether Exo-181b could enhance osteointegration. RESULTS: In vitro, we firstly verified that Exo-181b significantly enhanced M2 polarization and inhibited inflammation by suppressing PRKCD and activating p-AKT. Then, in vivo, we verified that Exo-181b enhanced M2 polarization, reduced the inflammatory response and enhanced osteointegration. Also, we verified that the enhanced M2 polarization could indirectly promote the migration and osteogenic differentiation by secreting VEGF and BMP-2 in vitro. CONCLUSIONS: Exo-181b could suppress inflammatory response by promoting M2 polarization via activating PRKCD/AKT signaling pathway, which further promoting osteogenesis in vitro and promote osteointegration in vivo.

8.
BMC Med ; 19(1): 197, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34474668

RESUMO

BACKGROUND: Current methods for cervical cancer screening result in an increased number of referrals and unnecessary diagnostic procedures. This study aimed to develop and evaluate a more accurate model for cervical cancer screening. METHODS: Multiple predictors including age, cytology, high-risk human papillomavirus (hrHPV) DNA/mRNA, E6 oncoprotein, HPV genotyping, and p16/Ki-67 were used for model construction in a cross-sectional population including women with normal cervix (N = 1085), cervical intraepithelial neoplasia (CIN, N = 279), and cervical cancer (N = 551) to predict CIN2+ or CIN3+. A base model using age, cytology, and hrHPV was calculated, and extended versions with additional biomarkers were considered. External validations in two screening cohorts with 3-year follow-up were further conducted (NCohort-I = 3179, NCohort-II = 3082). RESULTS: The base model increased the area under the curve (AUC, 0.91, 95% confidence interval [CI] = 0.88-0.93) and reduced colposcopy referral rates (42.76%, 95% CI = 38.67-46.92) compared to hrHPV and cytology co-testing in the cross-sectional population (AUC 0.80, 95% CI = 0.79-0.82, referrals rates 61.62, 95% CI = 59.4-63.8) to predict CIN2+. The AUC further improved when HPV genotyping and/or E6 oncoprotein were included in the base model. External validation in two screening cohorts further demonstrated that our models had better clinical performances than routine screening methods, yielded AUCs of 0.92 (95% CI = 0.91-0.93) and 0.94 (95% CI = 0.91-0.97) to predict CIN2+ and referrals rates of 17.55% (95% CI = 16.24-18.92) and 7.40% (95% CI = 6.50-8.38) in screening cohort I and II, respectively. Similar results were observed for CIN3+ prediction. CONCLUSIONS: Compared to routine screening methods, our model using current cervical screening indicators can improve the clinical performance and reduce referral rates.

9.
Artigo em Inglês | MEDLINE | ID: mdl-34540319

RESUMO

The occurrence of coronavirus disease 2019 (COVID-19) was followed by a small burst of cases around the world; afterward, due to a series of emergency non-pharmaceutical interventions (NPIs), the increasing number of confirmed cases slowed down in many countries. However, the subsequent gradual easing of governance led to a sudden increase in cases in late July 2020, arousing deep concern across the globe. This study evaluates the situation of the COVID-19 pandemic in countries and territories worldwide from January 2020 to February 2021. According to the time-varying reproduction number (R(t)) of each country or territory, the results show that almost half of the countries and territories in the world have never controlled the epidemic. Among the countries and territories that had once contained the occurrence, nearly half failed to maintain their prevention and control, causing the COVID-19 pandemic to rebound across the world-resulting in even higher waves in half of the rebounding countries or territories. This work also proposes and uses a time-varying country-level transmission risk score (CTRS), which takes into account both R(t) and daily new cases, to demonstrate country-level or territory-level transmission potential and trends. Time-varying hierarchical clustering of time-varying CTRS values was used to successfully reveal the countries and territories that contributed to the recent aggravation of the global pandemic in the last quarter of 2020 and the beginning of 2021, and to identify countries and territories with an increasing risk of COVID-19 transmission in the near future. Furthermore, a regression analysis indicated that the introduction and relaxation of NPIs, including workplace closure policies and stay-at-home requirements, appear to be associated with recent global transmission changes. In conclusion, a systematic evaluation of the global COVID-19 pandemic over the past year indicates that the world is now in an unexpected situation, with limited lessons learned. Summarizing the lessons learned could help in designing effective public responses for constraining future waves of COVID-19 worldwide.

10.
J Genet Genomics ; 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34537414

RESUMO

Multi-factors have been reported to affect the gut microbiome, including genotype, age, diet, and nutrition. However, few reports have investigated the relative capacity of different factors to shape the gut microbiome in a single study. Our design used a genetic Vitamin A deficient mouse model, the Rbp4-/- mouse, feeding with the low Vitamin A diets at different ages of initiation (4 or 7 weeks) for 28 days. Fecal samples were collected for bacterial profiling at seven time points after diet controlling. With RBP4 depletion, Akkermansia decreased and Bacteroides increased, while Desulfovibrio, Barnesiella, Clostridium_XlVa, and Lactobacillus fluctuated. The bacterial community swiftly adjusted with the Vitamin A-deficient diet administration and gradually changed (e.g., decrease of Barnesiella and increase of Desulfovibrio). Age exerted a relatively weaker but long-last influence. At an earlier age to feed a Vitamin-A deficient diet, a higher microbial dysbiosis index (MDI) will be valued. Of note, the shaping effects of diet and age on the bacterial community varied with the difference of genotype, which might indicate a greater role of genotype than diet and age in shaping the gut microbiome.

11.
J Agric Food Chem ; 69(34): 9743-9753, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34465092

RESUMO

Indirect defense is an important strategy employed by sessile plants to defend against herbivorous insects by recruiting the natural enemies of herbivores mediated by herbivore-induced plant volatiles (HIPVs). We aimed to determine whether indirect defense occurs in Compositae with Chrysanthemum morifolium as the model and elucidate the mechanisms underlying the biosynthesis of HIPVs. Using two-choice olfactometer bioassays, we showed that C. morifolium plants following infestation by larvae of the tobacco cutworm (Spodoptera litura, TCW) were significantly more attractive to two natural enemies of TCW larvae than control plants, indicating that indirect defense is an active defense strategy of C. morifolium. The chemical cue responsible for indirect defense in C. morifolium was identified as a complex blend of volatiles predominated by sesquiterpenes and monoterpenes. A total of 11 candidate terpene synthase (TPS) genes were identified by comparing the transcriptomes of healthy and TCW-infested plants. Gene expression analysis confirmed that up-regulated CmjTPS genes are consistent with the elevated emission of terpenes after herbivory treatment. Our study showed that the herbivore-induced emission of JA-dependent volatile terpenes attracted both predatory and parasitic enemies of herbivores. Generally, our findings indicate that indirect defense might be an important defense mechanism against insects in C. morifolium.


Assuntos
Chrysanthemum , Herbivoria , Animais , Chrysanthemum/genética , Larva , Spodoptera/genética , Terpenos
12.
Phytochemistry ; 191: 112899, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34481346

RESUMO

Among the factors that have made flowering plants the most species-rich lineage of land plants is the interaction between flower and insect pollinators, for which floral scent plays a pivotal role. Water lilies belong to the ANA (Amborellales, Nymphaeales, and Austrobaileyales) grade of basal flowering plants. In this study, Victoria cruziana was investigated as a model night-blooming water lily for floral scent biosynthesis. Four volatile compounds, including three benzenoids and one fatty acid methyl ester methyl hexanoate, were detected from the flowers of V. cruziana during their first bloom, with methyl hexanoate accounting for 45 % of total floral volatile emission. Emission rates were largely constant before significant drop starting at the end of second bloom. To understand the molecular basis of floral scent biosynthesis in V. cruziana, particularly methyl hexanoate, a transcriptome from the whole flowers at the full-bloom stage was created and analyzed. Methyl hexanoate was hypothesized to be biosynthesized by SABATH methyltransferases. From the transcriptome, three full-length SABATH genes designated VcSABATH1-3 were identified. A full-length cDNA for each of the three VcSABATH genes was expressed in Escherichia coli to produce recombinant proteins. When tested in in vitro methyltransferase enzyme assays with different fatty acids, both VcSABATH1 and VcSABATH3 exhibited highest levels of activity with hexanoic acid to produce methyl hexanoate, with the specific activity of VcSABATH1 being about 15 % of that for VcSABATH3. VcSABATH1 and VcSABATH3 showed the highest levels of expression in stamen and pistil, respectively. In phylogenetic analysis, three VcSABATH genes clustered with other water lily SABATH methyltransferase genes including the one known for making other fatty acid methyl esters, implying both a common evolutionary origin and functional divergence. Fatty acid methyl esters are not frequent constituents of floral scents of mesangiosperms, pointing to the importance for the evolution of novel fatty acid methyltransferase for making fatty acid methyl esters in the pollination biology of water lilies.


Assuntos
Nymphaea , Caproatos , Flores , Odorantes , Filogenia , Polinização
13.
Curr Med Imaging ; 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34533448

RESUMO

BACKGROUND: Lung transplantation might be a viable alternative for patients with irreversible lung injury secondary to coronavirus disease 2019 (COVID-19). Here, we describe two patients with end-stage COVID-19 that received lung transplantations, the clinical-radiologic manifestations of post-operative complications, and the imaging features of allograft rejection.

Case presentation: Case 1, a 66-year-old woman presented severe hypoxia after lung transplantation. Chest imaging revealed diffuse homogeneous infiltration in the donor lung. Dramatic resolution of the imaging abnormalities after intravenous administration of methylprednisolone favored a diagnosis of hyperacute rejection. The second is a 70-year-old man, who was infected with bacterial postoperatively. During the empiric antibiotic therapy, chest CT showed newly developed ground glass opacities with septal thickening, suggesting a diagnosis of acute rejection. High-dose corticosteroids therapy was initiated, and the patient recovered gradually.

Conclusion: This is the first report describing post-operative complications of lung transplantation in patients with advanced COVID-19. We presumed that imaging procedures could be a useful tool in early detecting lung transplant complications and selecting specific interventions for patients with COVID-19.

14.
Pharm Biol ; 59(1): 1245-1255, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34511043

RESUMO

CONTEXT: Icariin has attracted increasing attention because of its wide variety of pharmacological effects. OBJECTIVE: This study investigates whether icariin could promote fracture healing in young and old rats and its mechanisms. MATERIALS AND METHODS: A Wistar rat model for the tibia fracture in relatively young and old rats, respectively, was established. The rats were divided into four groups: model group, L-icariin (50 mg/kg icariin), M-icariin (100 mg/kg icariin) and H-icariin (200 mg/kg icariin), and intragastric administration of icariin was performed for 10 days or 20 days. In addition, isolated and cultured rat bone mesenchymal stem cells (rBMSCs) from young and old rats were cultured with 5% and 20% of icariin-containing serum, respectively, then cell viability and alkaline phosphatase (ALP) activity were measured. RESULTS: Icariin administration induced the expression of Runx2, Osterix, BMP-2, p-Smad5 and osteocalcin secretion (young rats: model: 2.50 ± 0.71; L-icariin: 10.10 ± 1.55; M-icariin: 24.95 ± 2.19; H-icariin: 36.80 ± 2.26; old rats: model: 1.55 ± 0.49; L-icariin:6.55 ± 0.50; M-icariin: 15.00 ± 0.85; H-icariin:20.50 ± 2.27) at the fracture site, and increased the levels of bone formation markers (OC, BAP, NTX-1 and CTX-1) in a dose-dependent manner. In vitro, icariin treatment promoted rBMSC viability, increased ALP activity and the expression of BMP-2/Smad5/Runx2 pathway proteins. DISCUSSION AND CONCLUSIONS: Icariin may accelerate fracture healing by activating the BMP-2/Smad5/Runx2 pathway in relatively young and old rats. The research on the mechanism of icariin to promote fracture healing can provide a theoretical basis for the clinical application and promotion of icariin.

15.
Am J Manag Care ; 27(9): e330-e335, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34533916

RESUMO

OBJECTIVES: Whether and how the COVID-19 pandemic affected utilization of routine medical care in areas with low infection risk, such as Taiwan, has not been widely addressed. We aimed to evaluate the impact of the COVID-19 pandemic on access to medical care. STUDY DESIGN: Before and after exposure (COVID-19 pandemic) design with a historical control group for comparison of clinical visits based on a retrospective cohort of 6722 customary patients of a community hospital in Zhunan, Taiwan. METHODS: Repeated measurements of medical utilization in 4-month periods (January to April) of 2019 and 2020 in light of the emerging COVID-19 pandemic were collected. Access to medical care was defined as the mean frequencies of clinical visits. The impacts of the COVID-19 pandemic on access in the overall and specific groups were quantified with a multivariable Poisson regression model. RESULTS: The overall outpatient visits per month declined by 39% (rate ratio [RR], 0.61; P < .0001) after adjusting for demographics. A notable reduction in visits was observed in foreign patients (RR, 0.50; P < .0001). The visits of the elderly (≥ 80 years) were the most frequent before the COVID-19 pandemic but were reduced by 44% (RR, 0.56; P < .0001) after it began. Most disease categories revealed a declining trend, but the size of reduction varied by International Classification of Diseases codes. CONCLUSIONS: The COVID-19 pandemic prevented some individuals from keeping regular medical appointments even in an area with a low infection risk. Our findings imply that more research is required to mitigate the effects of delayed medical care for patients who infrequently utilized medical care during and after the long-lasting pandemic period.

16.
J Agric Food Chem ; 69(37): 10907-10919, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34461020

RESUMO

Moderate red wine consumption has been linked to reduced chronic disease risk. Thus far, little has been known about the physicochemical properties and potential biological effects of high-molecular-weight polyphenolic complexes (HPPCs), a major fraction of red wine polyphenols. In this work, the stability and biochemical properties of HPPCs under simulated gastrointestinal conditions in vitro were studied. The results showed that HPPCs were resistant to simulated gastric digestion (SGD) and simulated intestinal digestion (SID). They exhibited significant inhibitory activity against key metabolic syndrome-associated digestive enzymes, achieving 17.1-90.9% inhibition of pancreatic α-amylase, lipase, and cholesterol esterase at 0.02-0.45 mg/mL. HPPCs were metabolized by gut microbiota (GM), leading to significantly enhanced antioxidant capacity when compared with the original, SGD, and SID samples. Furthermore, they favorably modulated GM profiles, which was accompanied by significantly increased short-chain fatty acid generation during the early colonic fermentation phase. These findings suggest that HPPCs are a promising modulator of human metabolic disease risk.

18.
BMC Womens Health ; 21(1): 284, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34348700

RESUMO

BACKGROUND: Adenomyoepithelioma (AME) of the breast is a rare subtype of breast tumor. Most of AMEs reported are solid, however, cystic or prominent cystic changes are extremely rare. CASE PRESENTATION: A 51-year-old woman presented a lump in the upper outer quadrant of right breast, and it was accompanied by continuous breast pain and bilateral axillary itching for more than 2 months. There were no other symptoms found. Preoperative mammography and ultrasound examination were performed. Mammography showed a noncalcified lobulated mass, and it was considered to be a benign cyst with septum on ultrasound, but ductal carcinoma of breast, adenoid cystic carcinoma could not be excluded. At first, AME was not considered preoperatively, because the imaging features of this rare tumor may vary widely, which may result in an incorrect diagnosis. But eventually, AME was diagnosed by postoperative pathology and immunohistochemistry. CONCLUSION: We herein present a rare case of breast AME with prominent cystic changes. AME has no-specific imaging features, but the benign or malignant nature of the lesion might be suspected on imaging.


Assuntos
Adenomioepitelioma , Neoplasias da Mama , Carcinoma Adenoide Cístico , Adenomioepitelioma/diagnóstico por imagem , Adenomioepitelioma/cirurgia , Mama/diagnóstico por imagem , Mama/cirurgia , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/cirurgia , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade
19.
Plant Biotechnol J ; 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34375461

RESUMO

Azalea belongs to Rhododendron, which is one of the largest genera of flowering plants and is well known for the diversity and beauty in its more than 1000 woody species. Rhododendron contains two distinct groups: the most high-altitude and a few low-altitude species; however, the former group is difficult to be domesticated for urban landscaping, and their evolution and adaptation are little known. Rhododendron ovatum has broad adaptation in low-altitude regions but possesses evergreen characteristics like high-altitude species, and it has floral fragrance that is deficient in most cultivars. Here we report the chromosome-level genome assembly of R. ovatum, which has a total length of 549 Mb with scaffold N50 of 41 Mb and contains 41 264 predicted genes. Genomic micro-evolutionary analysis of R. ovatum in comparison with two high-altitude Rhododendron species indicated that the expansion genes in R. ovatum were significantly enriched in defence responses, which may account for its adaptability in low altitudes. The R. ovatum genome contains much more terpene synthase genes (TPSs) compared with the species that lost floral fragrance. The subfamily b members of TPS are involved in the synthesis of sesquiterpenes as well as monoterpenes and play a major role in flora scent biosynthesis and defence responses. Tandem duplication is the primary force driving expansion of defence-responsive genes for extensive adaptability to the low-altitude environments. The R. ovatum genome provides insights into low-altitude adaptation and gain or loss of floral fragrance for Rhododendron species, which are valuable for alpine plant domestication and floral scent breeding.

20.
Infection ; 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34409563

RESUMO

PURPOSE: To estimate the central tendency and dispersion for incubation period of COVID-19 and, in turn, assess the effect of a certain length of quarantine for close contacts in active monitoring. METHODS: Literature related to SARS-CoV-2 and COVID-19 was searched through April 26, 2020. Quality was assessed according to Agency for Healthcare Research and Quality guidelines. Log-normal distribution for the incubation period was assumed to estimate the parameters for each study. Incubation period median and dispersion were estimated, and distribution was simulated. RESULTS: Fifty-six studies encompassing 4095 cases were included in this meta-analysis. The estimated median incubation period for general transmissions was 5.8 days [95% confidence interval (95% CI): 5.3, 6.2]. Incubation period was significantly longer for asymptomatic transmissions (median: 7.7 days; 95% CI 6.3, 9.4) than for general transmissions (P = 0.0408). Median and dispersion were higher for SARS-CoV-2 incubation compared to other viral respiratory infections. Furthermore, about 12 in 10,000 contacts in active monitoring would develop symptoms after 14 days, or below 1 in 10,000 for asymptomatic transmissions. Meta-regression suggested that each 10-year increase in age resulted in an average 16% increment in length of median incubation (incubation period ratio, 1.16, 95% CI 1.01, 1.32; P = 0.0250). CONCLUSION: This study estimated the median and dispersion of the SARS-CoV-2 incubation period more precisely. A 14-day quarantine period is sufficient to trace and identify symptomatic infections.

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