Structural elucidation of hemicelluloses from oil-tea camellia fruit shell.

Oil-tea camellia fruit shell (CFS) is a very abundant waste lignocellulosic resource. The current treatments of CFS, i.e. composting and burning, pose a severe threat on environment. Up to 50 % of the dry mass of CFS is composed of hemicelluloses. However, chemical structures of the hemicelluloses in CFS have not been extensively studied, which limits their high-value utilization. In this study, different types of hemicelluloses were isolated from CFS through alkali fractionation with the assistance of Ba(OH)2 and H3BO3. Xylan, galacto-glucomannan and xyloglucan were found to be the major hemicelluloses in CFS. Through methylation, HSQC and HMBC analyses, we have found that the xylan in CFS is composed of →4)-ß-D-Xylp-(1→ and →3,4)-ß-D-Xylp-(1→ linked by (1→4)-ß glycosidic bond as the main chain; the side chains are α-L-Fucp-(1→, →5)-α-L-Araf-(1→, ß-D-Xylp-(1→, α-L-Rhap-(1→ and 4-O-Me-α-D-GlcpA-(1→, connected to the main chain through (1→3) glycosidic bond. The main chain of galacto-glucomannan in CFS consists of →6)-ß-D-Glcp-(1→, →4)-ß-D-Glcp-(1→, →4,6)-ß-D-Glcp-(1→ and →4)-ß-D-Manp-(1→; the side chains are ß-D-Glcp-(1→, →2)-ß-D-Galp-(1→, ß-D-Manp-(1→ and →6)-ß-D-Galp-(1→ connected to the main chain through (1→6) glycosidic bonds. Moreover, galactose residues are connected by α-L-Fucp-(1→. The main chain of xyloglucan is composed of →4)-ß-D-Glcp-(1→, →4,6)-ß-D-Glcp-(1→ and →6)-ß-D-Glcp-(1→; the side groups, i.e. ß-D-Xylp-(1→ and →4)-ß-D-Xylp-(1→, are connected to the main chain by (1→6) glycosidic bond; →2)-ß-D-Galp-(1→ and α-L-Fucp-(1→ can also connect to →4)-ß-D-Xylp-(1→ forming di- or trisaccharide side chains.

Computed tomography-based COVID-19 triage through a deep neural network using mask-weighted global average pooling.

Background: There is an urgent need to find an effective and accurate method for triaging coronavirus disease 2019 (COVID-19) patients from millions or billions of people. Therefore, this study aimed to develop a novel deep-learning approach for COVID-19 triage based on chest computed tomography (CT) images, including normal, pneumonia, and COVID-19 cases. Methods: A total of 2,809 chest CT scans (1,105 COVID-19, 854 normal, and 850 non-3COVID-19 pneumonia cases) were acquired for this study and classified into the training set (n = 2,329) and test set (n = 480). A U-net-based convolutional neural network was used for lung segmentation, and a mask-weighted global average pooling (GAP) method was proposed for the deep neural network to improve the performance of COVID-19 classification between COVID-19 and normal or common pneumonia cases. Results: The results for lung segmentation reached a dice value of 96.5% on 30 independent CT scans. The performance of the mask-weighted GAP method achieved the COVID-19 triage with a sensitivity of 96.5% and specificity of 87.8% using the testing dataset. The mask-weighted GAP method demonstrated 0.9% and 2% improvements in sensitivity and specificity, respectively, compared with the normal GAP. In addition, fusion images between the CT images and the highlighted area from the deep learning model using the Grad-CAM method, indicating the lesion region detected using the deep learning method, were drawn and could also be confirmed by radiologists. Conclusions: This study proposed a mask-weighted GAP-based deep learning method and obtained promising results for COVID-19 triage based on chest CT images. Furthermore, it can be considered a convenient tool to assist doctors in diagnosing COVID-19.

Phytochemical constituents of Camellia osmantha fruit cores with antithrombotic activity.

Camellia osmantha is a new species of the genus Camellia and is an economically important ornamental plant. Its activity and ingredients are less studied than other Camellia plants. This study investigated the antithrombotic effect and chemical components of C. osmantha fruit cores using platelet aggregation assays and coagulation function tests. The cores of C. osmantha fruits were extracted with ethanol to obtain a crude extract. The extract was dissolved in water and further eluted with different concentrations of methanol on an MCI resin column to obtain three fractions. These samples were used for antithrombotic activity tests and phytochemical analysis. The results showed that the extract and its fractions of C. osmantha have strong antithrombotic activity, significantly reducing the platelet aggregation rate and prolonging the thrombin time (TT). The total saponins, flavonoids, and polyphenols in the active fractions may be responsible for the antithrombotic activity. The chemical constituents were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). Twenty-three compounds were identified rapidly and accurately. Among them, ellagic acid, naringenin, and quercetin 3-O-glucuronide may be important antithrombotic constituents. Furthermore, interactions between these compounds and the P2Y1 receptor were investigated via molecular modeling, because the P2Y1 receptor is a key drug target of antiplatelet aggregative activity. The molecular docking results suggested that these compounds could combine tightly with the P2Y1R protein. Our results showed that C. osmantha fruit cores are rich in polyphenols, flavonoids, and saponins, which can be developed into a promising antithrombotic functional beverage for the prevention and treatment of cardiovascular and cerebrovascular diseases.

The complete chloroplast genome sequence of Camellia rostrata S. X. Yang & S. F. Chai (Theaceae), a critically endangered yellow camellia from southwest China.

Camellia rostrata S. X. Yang & S. F. Chai is a recently described yellow camellia species from Guangxi, China. It is a critically endangered species according to the IUCN Red List Categories and Criteria. Here, we report the complete chloroplast (cp) genome based on next-generation sequencing technology. The complete cp genome of C. rostrata is 156,547 bp in length and consists of a large single-copy (LSC, 86,199 bp) region, a small single-copy (SSC, 18,204 bp) region, and a pair of inverted repeats (IRs, 26,072 bp). The genome contains 135 genes including 40 tRNA, eight rRNA, and 87 protein-coding genes. Phylogenetic analysis resolved C. rostrata in a clade containing C. huana and C. impressinervis, both of which are classified to Camellia sect. Archecamellia. Our findings support the placement of C. rostrata in C. sect. Archecamellia as proposed by a previous study. The cp genome of C. rostrata provides valuable bioinformatic resources for the protection and utilization of this yellow camellia species.

The complete chloroplast genome sequence of Camellia zhaiana (Theaceae), a critically endangered species from China.

Camellia zhaiana S.X. Yang (Theaceae) is a recently described species reported from Guangxi, China. It was proposed as a critically endangered species according to the IUCN Red List Categories and Criteria. In this study, we report and characterize the complete chloroplast (cp) genome of C. zhaiana using Illumina pair-end sequencing data. This is the first report of a cp genome of a species classified in Camellia section. Longipedicellata. The cp genome of C. zhaiana is 156,627 bp in length and includes a large single-copy region (LSC, 86,196 bp), a small single-copy region (SSC, 18,281 bp), and a pair of inverted repeat regions (IRs, 26,075 bp). The genome contains 135 genes, including 40 tRNA, eight rRNA, and 87 protein-coding genes. Phylogenetic analysis showed a strongly supported sister relationship between C. zhaiana and C. longipedicellata, which is a species classified in sect. Longipedicellata. These data support the previous systematic findings of C. zhaiana and advance the bioinformatics of the genus Camellia.

Identification and expression analysis of PUB genes in tea plant exposed to anthracnose pathogen and drought stresses.

The plant U-box (PUB) gene family, one of the major ubiquitin ligase families in plants, plays important roles in multiple cellular processes including environmental stress responses and resistance. The function of U-box genes has been well characterized in Arabidopsis and other plants. However, little is known about the tea plant (Camellia sinensis) PUB genes. Here, 89 U-box proteins were identified from the chromosome-scale referenced genome of tea plant. According to the domain organization and phylogenetic analysis, the tea plant PUB family were classified into ten classes, named Class I to X, respectively. Using previously released stress-related RNA-seq data in tea plant, we identified 34 stress-inducible CsPUB genes. Specifically, eight CsPUB genes were expressed differentially under both anthracnose pathogen and drought stresses. Moreover, six of the eight CsPUBs were upregulated in response to these two stresses. Expression profiling performed by qRT-PCR was consistent with the RNA-seq analysis, and stress-related cis-acting elements were identified in the promoter regions of the six upregulated CsPUB genes. These results strongly implied the putative functions of U-box ligase genes in response to biotic and abiotic stresses in tea plant.

Feasibility of quantitative parameters of dynamically enhanced patterns of spiral computed tomography scanning integrated into tumour progression before targeted treatment of non-small cell lung cancer.

INTRODUCTION: The relationship between quantitative parameters of contrast-enhanced computed tomography (CT) and non-small cell lung cancer (NSCLC) progression remains controversial. We aimed to explore the usefulness of contrast-enhanced spiral CT scanning for confirming the time of tumour progression before targeted treatment of NSCLC. METHODS: Contrast-enhanced spiral CT scanning was performed on 33 NSCLC patients with a biopsy-proven diagnosis of NSCLC. All the patients were divided into three groups according to times of tumour progression (<6 weeks, 6-20 weeks, and >20 weeks). The perfusion CT data were used to calculate quantitative parameters, including enhanced peak values, peak time of tumour enhancement, ratio of tumour mass and enhanced aorta peak value and perfusion value of blood flow. Variance analysis was used for statistical analysis among the three groups using SAS 9.13 statistical software. RESULTS: Tumour perfusion values among the three group with different stage of TTP were significantly different from each other with P = 0.0129 (<6 weeks, perfusion value = 0.35 ± 0.15 mL/(min × mL); 6-20 weeks, perfusion value = 0.41 ± 0.086 mL/(min × mL); > 20 weeks, perfusion value = 0.47 ± 0.087 mL/(min × mL)). However, no significant differences were found in other parameters (enhanced peak values, peak time of tumour enhancement, ratios of tumour mass, and enhanced aorta peak value) among three groups (P > 0.05). CONCLUSION: The NSCLC patients with high perfusion value before targeted therapy are more sensitive to targeted therapy, and further experiments with larger sample size are needed.