Variation in leaf dark respiration among C3 and C4 grasses is associated with use of different substrates.

Measurements of respiratory properties have often been made at a single time point either during daytime using dark-adapted leaves or during nighttime. The influence of the day-night cycle on respiratory metabolism has received less attention but is crucial to understand photosynthesis and photorespiration. Here, we examined how CO2- and O2-based rates of leaf dark respiration (Rdark) differed between midday (after 30-min dark adaptation) and midnight in 8 C3 and C4 grasses. We used these data to calculate the respiratory quotient (RQ; ratio of CO2 release to O2 uptake), and assessed relationships between Rdark and leaf metabolome. Rdark was higher at midday than midnight, especially in C4 species. The day-night difference in Rdark was more evident when expressed on a CO2 than O2 basis, with the RQ being higher at midday than midnight in all species, except in rice (Oryza sativa). Metabolomic analyses showed little correlation of Rdark or RQ with leaf carbohydrates (sucrose, glucose, fructose, or starch) but strong multivariate relationships with other metabolites. The results suggest that rates of Rdark and differences in RQ were determined by several concurrent CO2-producing and O2-consuming metabolic pathways, not only the tricarboxylic acid cycle (organic acids utilization) but also the pentose phosphate pathway, galactose metabolism, and secondary metabolism. As such, Rdark was time-, type- (C3/C4) and species-dependent, due to the use of different substrates.

It's only natural: Plant respiration in unmanaged systems.

Respiration plays a key role in the terrestrial carbon cycle and is a fundamental metabolic process in all plant tissues and cells. We review respiration from the perspective of plants that grow in their natural habitat and how it is influenced by wide-ranging elements at different scales, from metabolic substrate availability to shifts in climate. Decades of field-based measurements have honed our understanding of the biological and environmental controls on leaf, root, stem, and whole-organism respiration. Despite this effort, there remain gaps in our knowledge within and across species and ecosystems, especially in more challenging-to-measure tissues like roots. Recent databases of respiration rates and associated leaf traits from species representing diverse biomes, plant functional types, and regional climates have allowed for a wider-lens view at modeling this important CO2 flux. We also re-analyze published data sets to show that maximum leaf respiration rates (Rmax) in species from around the globe are related both to leaf economic traits and environmental variables (precipitation and air temperature), but that root respiration does not follow the same latitudinal trends previously published for leaf data. We encourage the ecophysiological community to continue to expand their study of plant respiration in tissues that are difficult to measure and at the whole plant and ecosystem levels to address outstanding questions in the field.

The crucial roles of mitochondria in supporting C4 photosynthesis.

C4 photosynthesis involves a series of biochemical and anatomical traits that significantly improve plant productivity under conditions that reduce the efficiency of C3 photosynthesis. We explore how evolution of the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK types) has affected the functions and properties of mitochondria. Mitochondria in C4 NAD-ME and PCK types play a direct role in decarboxylation of metabolites for C4 photosynthesis. Mitochondria in C4 PCK type also provide ATP for C4 metabolism, although this role for ATP provision is not seen in NAD-ME type. Such involvement has increased mitochondrial abundance/size and associated enzymatic capacity, led to changes in mitochondrial location and ultrastructure, and altered the role of mitochondria in cellular carbon metabolism in the NAD-ME and PCK types. By contrast, these changes in mitochondrial properties are absent in the C4 NADP-ME type and C3 leaves, where mitochondria play no direct role in photosynthesis. From an eco-physiological perspective, rates of leaf respiration in darkness vary considerably among C4 species but does not differ systematically among the three C4 types. This review outlines further mitochondrial research in key areas central to the engineering of the C4 pathway into C3 plants and to the understanding of variation in rates of C4 dark respiration.

Dark respiration rates are not determined by differences in mitochondrial capacity, abundance and ultrastructure in C4 leaves.

Our understanding of the regulation of respiration in C4 plants, where mitochondria play different roles in the different types of C4 photosynthetic pathway, remains limited. We examined how leaf dark respiration rates (Rdark ), in the presence and absence of added malate, vary in monocots representing the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK) using intact leaves and extracted bundle sheath strands. In particular, we explored to what extent rates of Rdark are associated with mitochondrial number, volume and ultrastructure. Based on examination of a single species per C4 type, we found that the respiratory response of NAD-ME and PCK type bundle sheath strands to added malate was associated with differences in mitochondrial number, volume, and/or ultrastructure, while NADP-ME type bundle sheath strands did not respond to malate addition. In general, mitochondrial traits reflected the contributions mitochondria make to photosynthesis in the three C4 types. However, despite the obvious differences in mitochondrial traits, no clear correlation was observed between these traits and Rdark . We suggest that Rdark is primarily driven by cellular maintenance demands and not mitochondrial composition per se, in a manner that is somewhat independent of mitochondrial organic acid cycling in the light.

Responses of leaf respiration to heatwaves.

Mitochondrial respiration (R) is central to plant physiology and responds dynamically to daily short-term temperature changes. In the longer-term, changes in energy demand and membrane fluidity can decrease leaf R at a common temperature and increase the temperature at which leaf R peaks (Tmax ). However, leaf R functionality is more susceptible to short-term heatwaves. Catalysis increases with rising leaf temperature, driving faster metabolism and leaf R demand, despite declines in photosynthesis restricting assimilate supply and growth. Proteins denature as temperatures increase further, adding to maintenance costs. Excessive heat also inactivates respiratory enzymes, with a concomitant limitation on the capacity of the R system. These competing push-and-pull factors are responsible for the diminishing acceleration in leaf R rate as temperature rises. Under extreme heat, membranes become overly fluid, and enzymes such as the cytochrome c oxidase are impaired. Such changes can lead to over-reduction of the energy system culminating in reactive oxygen species production. This ultimately leads to the total breakdown of leaf R, setting the limit of leaf survival. Understanding the heat stress responses of leaf R is imperative, given the continued rise in frequency and intensity of heatwaves and the importance of R for plant fitness and survival.

[Evaluation of yogurt intake status of Chinese adults in 8 cities and its relationship with metabolic syndrome in 2016].

OBJECTIVE: To investigate the level of yogurt intake in the Chinese population and its relationship between the level of yogurt intake and metabolic syndrome. METHODS: Samples were taken from populations in 8 cities in China. Dietary surveys, physical examinations, and blood sample were collected. The level of yogurt intake of the population were calculated and evaluated. The relationship between yogurt intake and metabolic syndrome and its components was analyzed by multiple logistic regression. The yogurt intake was investigated using a diet frequency questionnaire to record the frequency and intake of yogurt in the past month. RESULTS: A total of 1508 respondents were included in this study, including 538 males and 970 females; the average age was 51.74 years; the distribution ratio in the North and South regions was 5∶4.The rate of Chinese population in 8 cities which eat yogurt was 50.1%. The intake of yogurt was 3.7 g/d. Yogurt accounts for 27.22% of dairy products. There were differences in the distribution of different yogurt intake groups in different genders, age groups, Body Mass Index(BMI)groups, regions, education levels, monthly income, and smoking. The differences in calcium, fruit, and total dairy product intake among different yogurt intake groups were statistically significant difference. Sample analysis found that yogurt intake was negatively correlated with metabolic syndrome and its components. We adjusted gender, age group, body mass index group, region, education grade, monthly income, smoking, total energy, protein, fat, Ca, fruit, total dairy products for multi-factor analysis and found that this negative correlation was weakened. But this negative correlation remained on abnormal blood glucose[OR=0.61(95%CI 0.42-0.89)]. CONCLUSION: The yoghurt intake of Chinese residents is low. The intake of yogurt has a negative correlation with abnormal blood glucose.

Leaf trait variation is similar among genotypes of Eucalyptus camaldulensis from differing climates and arises in plastic responses to the seasons rather than water availability.

We used a widely distributed tree Eucalyptus camaldulensis subsp. camaldulensis to partition intraspecific variation in leaf functional traits to genotypic variation and phenotypic plasticity. We examined if genotypic variation is related to the climate of genotype provenance and whether phenotypic plasticity maintains performance in a changing environment. Ten genotypes from different climates were grown in a common garden under watering treatments reproducing the wettest and driest edges of the subspecies' distribution. We measured functional traits reflecting leaf metabolism and associated with growth (respiration rate, nitrogen and phosphorus concentrations, and leaf mass per area) and performance proxies (aboveground biomass and growth rate) each season over a year. Genotypic variation contributed substantially to the variation in aboveground biomass but much less in growth rate and leaf traits. Phenotypic plasticity was a large source of the variation in leaf traits and performance proxies and was greater among sampling dates than between watering treatments. The variation in leaf traits was weakly correlated to performance proxies, and both were unrelated to the climate of genotype provenance. Intraspecific variation in leaf traits arises similarly among genotypes in response to seasonal environmental variation, instead of long-term water availability or climate of genotype provenance.

[Dietary evaluation of 52 lactating mothers in Beijing in 2018 and its relationship with breast milk composition].

OBJECTIVE: To investigate the dietary nutrition status of lactating mothers in Beijing and the relationship between dietary nutrition level and breast milk composition. METHODS: Using convenient sampling, fifty-two lactating mothers were investigated and their breast milk was collected from May 2018 to July 2018. Dietary nutrient intake and the incidence of insufficiency nutrients intake were calculated. Dietary nutrient intake was compared with the dietary reference intake of Chinese residents. The relationship between dietary nutrition and breast milk composition was analyzed by multiple linear regression. RESULTS: The total energy intake was(1674. 15±655. 85) kcal, which was lower than the recommended value; protein(72. 77(45. 33, 92. 25)g), fat(66. 94(39. 26, 83. 83)g) and carbohydrates((208. 34±85. 77)g) were insufficient, of which the energy supply ratio of carbohydrates(49. 8%) was lower than the recommended value, while the protein(17. 39%) and fat(35. 99%) were higher than the recommended value. The insufficiency rate of vitamin A(73. 1%), folic acid(76. 9%), calcium(75. 0%) were also high. The ratio of energy produced by three meals was about 3∶4∶3, and the proportion of high-quality protein in dietary protein exceeded 50%. The fat(P=0. 007), dry matter(P=0. 006) and total energy(P=0. 006) in breast milk were affected by the protein in the diet, but protein(P=0. 283)and sugar(P=0. 307) in breast milk were not affected by dietary factors. CONCLUSION: The intakes of many nutrients of lactating mother are insufficient, especially energy and macronutrients. The fat, dry matter and total energy in breast milk are affected by the protein in the diet.

Transcriptomic analysis of small intestinal mucosa from porcine epidemic diarrhea virus infected piglets.

Caused by porcine epidemic diarrhea virus (PEDV), porcine epidemic diarrhea (PED) is an acute infectious disease which causes damage to the intestine including intestinal villus atrophy and shedding, leading to serious economic losses to the pig industry worldwide. In order to obtain detailed information about the pathogenesis and host immune response in a PEDV-infected host for first In vivo study we used high-throughput sequencing to analyze the gene expression differences of the small intestinal mucosa after infection with PEDV. Transcripts obtained were over 65,525,000 clean reads after reassembly were 22,605 genes detected, of which 22,248 were known genes and 371 new genes were predicted. Moreover, 3168 genes expression was up-regulated and 3876 genes down-regulated. (Gene Ontology) GO annotation and functional enrichment analysis indicated that all of the DEGs (differentially expressed genes) were annotated into biological process, cellular component and molecular function. Most of these unigenes are annotated in cellular processes, the cell and binding. KEGG analysis of the DEGs showed that a total of 7044 DEGs unigenes were annotated into 323 pathways classified into 6 main categories. Most of these unigenes are annotated were related to immune system response to the infectious diseases pathways. In addition, 20 DEGs were verified by quantitative real-time PCR. As the first, in vivo, RNAseq analysis of piglets and PEDV infection, our study provides knowledge about the transcriptomics of intestinal mucosa in PEDV-infected piglets, from which a complex molecular pathways and pathogenesis-related biological processes are involved in PEDV interaction with piglet intestinal mucosa.

Gut bacterial profiles in Parkinson's disease: A systematic review.

INTRODUCTION: Recent advances have highlighted the relationships between gut dysbiosis and Parkinson's disease (PD). Microbiota transplantation from PD patients to mice can induce increased alpha-synuclein-mediated motor deficits. Human studies have identified differences in the gut microbiota of PD patients compared to healthy controls. We undertook a systematic review to evaluate the available evidence for the involvement of gut bacteria in the etiology of PD. METHODS: The PubMed databank, the China National Knowledge Infrastructure databank, and Wanfang Data were searched from inception until June 2021 to identify human case-control studies that investigated relationships between PD and microbiota quantified from feces. We evaluated the resulting studies focusing on bacterial taxa that were different between PD patients and healthy controls. RESULTS: Twenty-six studies were found in which 53 microbial families and 98 genera exhibited differences between patients with PD and healthy controls. The genera identified by more than two studies as increased in PD were Bifidobacterium, Alistipes, Christensenella, Enterococcus, Oscillospira, Bilophila, Desulfovibrio, Escherichia/Shigella, and Akkermansia, while Prevotella, Blautia, Faecalibacterium, Fusicatenibacter, and Haemophilus had three or more reports of being lower in PD patients. More than one report demonstrated that Bacteroides, Odoribacter, Parabacteroides, Butyricicoccus, Butyrivibrio, Clostridium, Coprococcus, Lachnospira, Lactobacillus, Megasphaera, Phascolarctobacterium, Roseburia, Ruminococcus, Streptococcus, and Klebsiella were altered in both directions. CONCLUSION: Our review shows that the involvement of the gut microbiome in the etiology of PD may involve alterations of short-chain fatty acids (SCFAs)-producing bacteria and an increase in putative gut pathobionts. SCFAs-producing bacteria may vary above or below an "optimal range," causing imbalances. Considering that Bifidobacterium, Lactobacillus, and Akkermansia are beneficial for human health, increased Bifidobacterium and Lactobacillus in the PD gut microbiome may be associated with PD medications, especially COMT inhibitors, while a high level of Akkermansia may be associated with aging.

Oral, Nasal, and Gut Microbiota in Parkinson's Disease.

Parkinson's disease (PD) is the second most frequently diagnosed neurodegenerative disease. The purpose of this study was to investigate the link between microbiota composition in important mucosal interfaces (oral, nasal, and intestinal) and PD. Sequencing was undertaken of the V4-V5 region of the 16S ribosomal RNA (rRNA) gene of the microbiome from the oral cavity, nasal cavity, and gut of 91 PD patients and 91 healthy controls. Significant differences were found in microbiota composition in the oral cavity and gut, but not the nasal cavity, between PD patients and healthy controls after adjusting for age, gender, and body mass index (BMI). More genera in the oral cavity were significantly positively correlated with clinical characteristics, such as the HAMA and HAMD rating scales. The taxa c_Clostridia, o_Clostridiales, and f_Ruminococcaceae in the gut microbiota were associated with weight and MMSE score. Furthermore, as a result of dysbiosis, there was an enrichment of ion channel-, oxidative phosphorylation-, and carbohydrate metabolism-related pathways in the oral cavity and glycolysis/gluconeogenesis- and propanoate metabolism-related pathways in the intestine. Changes in these pathways can influence metabolism and inflammation, thereby contributing to PD pathogenesis. In addition, several subnetworks containing differentially abundant microbiota in the oral cavity and gut samples from PD patients may regulate microbial composition and function in PD. Overall, our results indicate that oral and gut dysbiosis may affect PD progression and provide a basis for understanding the pathogenesis of PD and identifying potential therapeutic targets for the treatment of this disease.

Notch signaling maintains proliferation and survival of the HL60 human promyelocytic leukemia cell line and promotes the phosphorylation of the Rb protein.

The Notch signaling pathway has been implicated in the development of several leukemia and lymphoma. In order to investigate the relationship between Notch signaling and acute myeloid leukemia (AML), in this study, we expressed a recombinant Notch ligand protein, the DSL domain of the human Jagged1 fused with GST (GST-Jag1). GST-Jag1 could activate Notch signaling in the human promyelocytic leukemia cell line HL60, as shown by a reporter assay and the induced expression of Notch effector gene Hes1 and Hes5. However, GST-Jag1 had no effect on the proliferation and survival of HL60 cells. HL60 cells expressed both Notch ligands and receptors, and had a potential of reciprocal stimulation of Notch signaling between cells. We, therefore, blocked Notch signaling in cultured HL60 cells using a gamma-secretase inhibitor (GSI). We found that GSI inhibited the proliferation of HL60 cells significantly by blocking the cell-cycle progression in the G1 phase. Furthermore, GSI induced remarkably apoptosis of HL60 cells. These changes in GSI-treated HL60 cells correlated with the down-regulation of c-Myc and Bcl2, and the low phosphorylation of the Rb protein. These results suggested that reciprocal Notch signaling might be necessary for the proliferation and survival of AML cells, possibly through the maintenance of the expression of c-Myc and Bcl2, as well as the phosphorylation of the Rb protein.

[Effects of genistein on colon cancer cells in vitro and in vivo and its mechanism of action].

OBJECTIVE: To study the effects of genistein on the proliferation, apoptosis induction and expression of related gene proteins of human colon cancer cells in vitro and in vivo, and its mechanisms of action. METHODS: MTT colorimetric assay was used to detect the effects of genistein on the proliferation of human colon adenocarcinoma SW480 cells. Light and transmission electron microscopy were used to study the histological and ultrastructural changes. Flow cytometry was used to determine the effects of genistein on cell cycle and apoptosis. Flow cytometry and immunohistochemistry were used to determine the effects of genistein on apoptosis induction and expression of related gene proteins of colon cancer cells. RESULTS: The MTT colorimetric assay showed that genistein inhibited the proliferation of SW480 cells in a dose-dependent and time-dependent manner, and the highest inhibition rate was 60.2% after 80 microg/ml genistein treatment for 72 h. The light microscopy revealed that many genistein-treated cancer cells were shrunken, disrupted, or showing cytoplasmic vacuolization. The electron microscopic examination showed cell shrinkage, nuclear fragmentation and pronounced chromatin condensation, sometimes formed crescent chromatin condensation attached to the nuclear membrane. The results of flow cytometry showed that: after SW480 cells were treated with 0, 20, 40, 80 microg/ml genistein for 48 h, the FI values of PCNA were 1.49 +/- 0.02, 1.28 +/- 0.04, 1.14 +/- 0.03, and 0.93 +/- 0.08; the FI values of VEGF were 1.75 +/- 0.02, 1.34 +/- 0.06, 1.32 +/- 0.04, and 1.23 +/- 0.04; the fluorescence index (FI) values of p21 were 1.26 +/- 0.05, 1.36 +/- 0.06, 1.61 +/- 0.03, and 1.73 +/- 0.03, respectively. There were statistically significant differences between the control group and each treatment group (P < 0.05 or P < 0.01). The scores of immunohistochemical staining of PCNA and VEGF proteins were decreased, while p21 increased. There were statistically significant differences between the control group and each treatment group (P < 0.05 or P < 0.01). CONCLUSION: Genistein can inhibit the growth of colon cancer cells via apoptosis induction and cell cycle arrest at G(2)/M phase. The anti-tumor mechanisms of genistein may be related with the down-regulation of expression of VEGF and PCNA, and up-regulation of the expression of p21.

The combination of gas-phase fluorophore technology and automation to enable high-throughput analysis of plant respiration.

BACKGROUND: Mitochondrial respiration in the dark (Rdark) is a critical plant physiological process, and hence a reliable, efficient and high-throughput method of measuring variation in rates of Rdark is essential for agronomic and ecological studies. However, currently methods used to measure Rdark in plant tissues are typically low throughput. We assessed a high-throughput automated fluorophore system of detecting multiple O2 consumption rates. The fluorophore technique was compared with O2-electrodes, infrared gas analysers (IRGA), and membrane inlet mass spectrometry, to determine accuracy and speed of detecting respiratory fluxes. RESULTS: The high-throughput fluorophore system provided stable measurements of Rdark in detached leaf and root tissues over many hours. High-throughput potential was evident in that the fluorophore system was 10 to 26-fold faster per sample measurement than other conventional methods. The versatility of the technique was evident in its enabling: (1) rapid screening of Rdark in 138 genotypes of wheat; and, (2) quantification of rarely-assessed whole-plant Rdark through dissection and simultaneous measurements of above- and below-ground organs. DISCUSSION: Variation in absolute Rdark was observed between techniques, likely due to variation in sample conditions (i.e. liquid vs. gas-phase, open vs. closed systems), indicating that comparisons between studies using different measuring apparatus may not be feasible. However, the high-throughput protocol we present provided similar values of Rdark to the most commonly used IRGA instrument currently employed by plant scientists. Together with the greater than tenfold increase in sample processing speed, we conclude that the high-throughput protocol enables reliable, stable and reproducible measurements of Rdark on multiple samples simultaneously, irrespective of plant or tissue type.

[Construction and expression of fusion protein TRX-hJagged1 in E.coli BL21].

This study was purposed to construct prokaryotic expression vector and to investigate the expression of Notch ligand Jagged1 in E.coli. An expression vector pET-hJagged1 was constructed, which can be inserted in Jagged1 with different lengths, but the DSL domain of human Jagged1 should be contained. Then the recombinant plasmids were transformed into the competent cell of E.coli BL21, and the expression of the fusion protein was induced by IPTG. Fusion protein was purified from the supernatant of cell lysates via the Nickel affinity chromatography. The results showed that prokaryotic expression vectors pET-hJagged1 (Bgl II), pET-hJagged1 (Hind I) and pET-hJagged1 (Stu I) were successfully constructed, but only pET-hJagged1 (Stu I) could express the soluble TRX-hJagged1. The purified TRX-Jagged1 protein could be obtained via the Nickel affinity chromatography, and then confirmed by Western Blot. It is concluded that prokaryotic expression vector pET-hJagged1 is successfully constructed, but only pET-hJagged1 (Stu I) can express the soluble TRX-hJagged1 and the TRX-Jagged1 fusion protein is obtained through the prokaryotic expression system, which laid a solid foundation for further to explore the effects of Jagged1 in hematopoietic and lymphoid system.