Transcriptome and Metabonomics Combined Analysis Revealed the Defense Mechanism Involved in Hydrogen-Rich Water-Regulated Cold Stress Response of Tetrastigma hemsleyanum.

The poor resistance to cold stress conditions has become the bottleneck problem in Tetrastigma hemsleyanum (T. hemsleyanum) planting industry. Exogenous hydrogen (H2) plays an important role in improving stress resistance in plants. However, the key factors and regulatory network of plants in response to hydrogen-rich water (HRW) treatment under environmental stress are not clear. Here, we conducted integrative analyses of metabolome and transcriptome profiles to reveal the defense mechanism involved in the HRW-regulated cold stress response of T. hemsleyanum. The application of 75% HRW could alleviate stress damage by decreasing stomatal apparatus density and significantly increasing photosynthetic efficiency and mitigating physiological indexes of resistance, such as Pn, Cond, MDA, SOD, etc., which were changed by cold stress conditions. A total of 7,883 DEGs and 439 DEMs were identified. DEGs were the most relevant to phenylpropanoid, isoflavonoid, monoterpenoid, and flavonoid biosynthesis pathways. Using gene co-expression analysis (WGCNA), we identified one gene module that showed a strong correlation between total antioxidant capacity and transpiration rate. Trend analysis indicated that the phenylpropanoid biosynthesis pathway played a major role in the transcription and metabolism process of HRW treatment under cold stress. Based on the integrated analysis of genes and metabolites, the results showed cold stress upregulated the expression of PAL, CHS, COMT, CCR, AtBG1, etc., resulting in the accumulation of coniferyl alcohol and eriodictyol contents in T. hemsleyanum under cold stress, but the 75% HRW treatment could attenuate the enhancement. The study not only identified the main strategy of HRW protection against cold stress but also provided candidate genes for flavonoid biosynthesis, so as to better improve cold tolerance through molecular breeding techniques.

The effect of a loading dose of meropenem on outcomes of patients with sepsis treated by continuous renal replacement: study protocol for a randomized controlled trial.

BACKGROUND: Sepsis and continuous renal replacement therapy (CRRT) are both responsible for the alterations of the pharmacokinetics of antibiotics. For patients with sepsis receiving CRRT, the serum concentrations of meropenem in the early phase (< 48 h) was significantly lower than that in the late phase (> 48 h). This current trial aimed to investigate whether administration of a loading dose of meropenem results in a more likely achievement of the pharmacokinetic (PK)/pharmacodynamics (PD) target (100% fT > 4 × MIC) and better therapeutic results in the patients with sepsis receiving CRRT. METHODS: This is a single-blinded, single-center, randomized, controlled, two-arm, and parallel-group trial. This trial will be carried out in Guangzhou First People's Hospital, School of Medicine, South China University of Technology Guangdong, China. Adult patients (age ≥ 18 years) with critical sepsis or sepsis-related shock receiving CRRT will be included in the study. The subjects will be assigned to the control group and the intervention group (LD group) randomly at a 1:1 ratio, the estimated sample size should be 120 subjects in each group. In the LD group, the patient will receive a loading dose of 1.5-g meropenem resolved in 30-ml saline which is given via central line for 30 min. Afterward, 0.75-g meropenem will be given immediately for 30 min every 8 h. In the control group, the patient will receive 0.75-g meropenem for 30 min every 8 h. The primary objective is the probabilities of PK/PD target (100% fT > 4 × MIC) achieved in the septic patients who receive CRRT in the first 48 h. Secondary objectives include clinical cure rate, bacterial clearance rate, sepsis-related mortality and all-cause mortality, the total dose of meropenem, duration of meropenem treatment, duration of CRRT, Sequential Organ Failure Assessment (SOFA), C-reactive protein levels, procalcitonin levels, white blood cell count, and safety. DISCUSSION: This trial will assess for the first time whether administration of a loading dose of meropenem results in a more likely achievement of the PK/PD target and better therapeutic results in the patients with sepsis receiving CRRT. Since CRRT is an important therapeutic strategy for sepsis patients with hemodynamic instability, the results from this trial may help to provide evidence-based therapy for septic patients receiving CRRT. TRIAL REGISTRATION: Chinese Clinical Trials Registry, ChiCTR2000032865 . Registered on 13 May 2020, http://www.chictr.org.cn/showproj.aspx?proj=53616 .

Identification of Chalcone Isomerase Family Genes and Roles of CnCHI4 in Flavonoid Metabolism in Camellia nitidissima.

Camellia nitidissima is a woody plant with high ornamental value, and its golden-yellow flowers are rich in a variety of bioactive substances, especially flavonoids, that are beneficial to human health. Chalcone isomerases (CHIs) are key enzymes in the flavonoid biosynthesis pathway; however, there is a scarcity of information regarding the CHI family genes of C. nitidissima. In this study, seven CHI genes of C. nitidissima were identified and divided into three subfamilies by phylogenetic analysis. The results of multiple sequence alignment revealed that, unlike CnCHI1/5/6/7, CnCHI2/3/4 are bona fide CHIs that contain all the active site and critical catalytic residues. Analysis of the expression patterns of CnCHIs and the total flavonoid content of the flowers at different developmental stages revealed that CnCHI4 might play an essential role in the flavonoid biosynthesis pathway of C. nitidissima. CnCHI4 overexpression significantly increased flavonoid production in Nicotiana tabacum and C. nitidissima. The results of the dual-luciferase reporter assay and yeast one-hybrid system revealed that CnMYB7 was the key transcription factor that governed the transcription of CnCHI4. The study provides a comprehensive understanding of the CHI family genes of C. nitidissima and performed a preliminary analysis of their functions and regulatory mechanisms.

Optimization of Ultrasonic-assisted Extraction and Fatty Acid Composition of Oil from Paeonia suffruticosa Andr. Seed.

Response surface methodology (RSM) was applied to optimize the effects of extraction parameters including time, power, temperature and liquid-to-solid ratio on peony seed oil yield. Box-Behnken design (BBD) was employed for optimization of extraction parameters in oil yield that extracted assisting by ultrasonic while petroleum ether as solvent. The chemical composition of peony seed oil under optimal condition in ultrasonic-assisted extract method was analyzed by gas chromatography-mass spectrometry (GC-MS). The optimal conditions were that extraction time 45 min, extraction temperature 45°C, extraction power 90 W and liquid-to-solid ratio 7:1, respectively. Under this condition, the extraction yield value was 33.90% which was with 95% confidence level, hence indicated the reliability of RSM in optimizing ultrasonic-assisted extraction of oil from Paeonia suffruticosa Andr. seed. Three unsaturated fatty acid of peony oil such as n-3 α-linolenic acid (39.75%), n-6 linoleic acid (26.32%) and the oleic acid (23.66%), totally more than 89.00% was determined at optimum condition.

Effect of Rhizophora apiculata plantation for improving water quality, growth, and health of mud crab.

A deteriorated water quality is closely associated with disease outbreaks in aquaculture, where microorganisms play indispensable roles in improving water quality and aquatic animals' health. Mangrove is known to be a natural water quality filter and microbiological buffer of pathogen and prebiotics. However, it is unclear how and to what extent Rhizophora apiculata plantation is of benefits to the gut microbiota and growth over mud crab (Scylla paramamosain) aging. To address these concerns, we explored the bacterial communities in mud crab gut and rearing water at 45, 114, and 132 days after incubation, roughly corresponding to juvenile, pre-adult, and adult stages of mud crab. Results showed that 1-year R. apiculata plantation slightly increased the body weight of mud crab and improved water quality to a certain extent. Both bacterioplankton and gut bacterial communities were highly temporal dynamic, while the two communities were significantly distinct (ANOSIM r = 0.90, P = 0.0001). Relative abundances of dominant taxa in water and gut significantly varied between the plantation and the control conditions over mud crab aging. R. apiculata plantation promoted the stability of gut microbiota, as evidenced by more diverse core species. Furthermore, R. apiculata plantation led to the dominance of Verrucomicrobiae species in water and probiotic Bacteroidetes and Lactobacillales taxa in gut. A structural equation model revealed that water variables directly constrained gut microbiota, which in turn affected the body weight of mud crab (r = 0.52, P < 0.001). In addition, functional pathways facilitating immunity and lipid metabolism significantly increased in mud crab gut under the plantation, while those involved in infectious diseases exhibited the opposing trend. These findings greatly expand our understanding of the R. apiculata plantation effects on water quality, gut microbiota, and growth feature of mud crab. Overall, R. apiculata plantation is beneficial for mud crab growth and health. KEY POINTS: • A short-term R. apiculata plantation could potentially improve water quality. • Bacterioplankton is more sensitive than mud crab gut microbiota in response to R. apiculata plantation. • R. apiculata plantation enhances mud crab resistance against pathogen invasion. • R. apiculata plantation alters mud crab gut microbiota, which in turn promotes their body weight.

Apatinib, a selective VEGFR2 inhibitor, improves the delivery of chemotherapeutic agents to tumors by normalizing tumor vessels in LoVo colon cancer xenograft mice.

Tumor vascular normalization has been proposed as a therapeutic strategy for malignant neoplasms, which can also interpret the synergistic effect of anti-angiogenesis agents combined with chemotherapy. Apatinib (Apa), a highly selective VEGFR2 inhibitor, attracts much attentions due to its encouraging anticancer activity, especially in the clinical trials of combined treatment. In this study, we investigated whether Apa could promote vascular normalization in tumor in a certain time window. Mice bearing LoVo colon cancer xenograft were orally administrated Apa (150 mg kg-1 per day) for 5, 7, 10, or 12 days. Apa significantly inhibited tumor growth and decreased the microvessel density. Using multi-photon microscopy and electron microscopy, we found that Apa improved tumor vessel morphology by pruning distorted vessel branches and decreased the gap between endothelial cells after a 7-day treatment. Furthermore, Apa decreased vessel leakage and increased pericyte coverage on vascular endothelial cells, suggesting that tumor vessels were more mature and integrated. The intratumoral distribution of adriamycin (ADR) in Apa group was improved from day 7 to 10 without change in plasma drug concentration. Tumor blood perfusion was also increased in this window, and the expression of hypoxia induced factor 1α was downregulated, suggesting the effect of Apa on alleviating tumor hypoxic micro-environment. In conclusion, Apa may improve the effective perfusion of tumor vessels and increase the intratumoral distribution of ADR in a certain time window via normalizing tumor vessels. This normalization window (7 to 10 days of treatment) may contribute to develop a regimen of combined medication in clinic use of Apa.

Starvation stress affects the interplay among shrimp gut microbiota, digestion and immune activities.

Aquatic animals are frequently suffered from starvation due to restricted food availability or deprivation. It is currently known that gut microbiota assists host in nutrient acquisition. Thus, exploring the gut microbiota responses would improve our understanding on physiological adaptation to starvation. To achieve this, we investigated how the gut microbiota and shrimp digestion and immune activities were affected under starvation stress. The results showed that the measured digestion activities in starved shrimp were significantly lower than in normal cohorts; while the measured immune activities exhibited an opposite trend. A structural equation modeling (SEM) revealed that changes in the gut bacterial community were directly related to digestive and immune enzyme activities, which in turn markedly affected shrimp growth traits. Notably, several gut bacterial indicators that characterized the shrimp nutrient status were identified, with more abundant opportunistic pathogens in starved shrimp, although there were no statistical differences in the overall diversity and the structures of gut bacterial communities between starved and normal shrimp. Starved shrimp exhibited less connected and cooperative interspecies interaction as compared with normal cohorts. Additionally, the functional pathways involved in carbohydrate and protein digestion, glycan biosynthesis, lipid and enzyme metabolism remarkably decreased in starved shrimp. These attenuations could increase the susceptibility of starved shrimp to pathogens infection. In summary, this study provides novel insights into the interplay among shrimp digestion, immune activities and gut microbiota in response to starvation stress.

De novo Assembly of the Camellia nitidissima Transcriptome Reveals Key Genes of Flower Pigment Biosynthesis.

The golden camellia, Camellia nitidissima Chi., is a well-known ornamental plant that is known as "the queen of camellias" because of its golden yellow flowers. The principal pigments in the flowers are carotenoids and flavonol glycosides. Understanding the biosynthesis of the golden color and its regulation is important in camellia breeding. To obtain a comprehensive understanding of flower development in C. nitidissima, a number of cDNA libraries were independently constructed during flower development. Using the Illumina Hiseq2500 platform, approximately 71.8 million raw reads (about 10.8 gigabase pairs) were obtained and assembled into 583,194 transcripts and 466, 594 unigenes. A differentially expressed genes (DEGs) and co-expression network was constructed to identify unigenes correlated with flower color. The analysis of DEGs and co-expressed network involved in the carotenoid pathway indicated that the biosynthesis of carotenoids is regulated mainly at the transcript level and that phytoene synthase (PSY), ß -carotene 3-hydroxylase (CrtZ), and capsanthin synthase (CCS1) exert synergistic effects in carotenoid biosynthesis. The analysis of DEGs and co-expressed network involved in the flavonoid pathway indicated that chalcone synthase (CHS), naringenin 3-dioxygenase (F3H), leucoanthocyanidin dioxygenase(ANS), and flavonol synthase (FLS) play critical roles in regulating the formation of flavonols and anthocyanidin. Based on the gene expression analysis of the carotenoid and flavonoid pathways, and determinations of the pigments, we speculate that the high expression of PSY and CrtZ ensures the production of adequate levels of carotenoids, while the expression of CHS, FLS ensures the production of flavonols. The golden yellow color is then the result of the accumulation of carotenoids and flavonol glucosides in the petals. This study of the mechanism of color formation in golden camellia points the way to breeding strategies that exploit gene technology approaches to increase the content of carotenoids and flavonol glucosides and to decrease anthocyanidin synthesis.

Overexpression of CaAPX Induces Orchestrated Reactive Oxygen Scavenging and Enhances Cold and Heat Tolerances in Tobacco.

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized an APX (CaAPX) gene from Camellia azalea. Quantitative real-time PCR (qRT-PCR) analysis showed that CaAPX was expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated with CaAPX expression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes including Cu/Zn-SOD, CAT, DHAR, and MDHAR, and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role of CaAPX to orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related to CaAPX expression and provides insights to breed crops with high temperature tolerances.