An 11-bp Insertion in Zea mays fatb Reduces the Palmitic Acid Content of Fatty Acids in Maize Grain

The ratio of saturated to unsaturated fatty acids in maize kernels strongly impacts human and livestock health, but is a complex trait that is difficult to select based on phenotype. Map-based cloning of quantitative trait loci (QTL) is a powerful but time-consuming method for the dissection of complex traits. Here, we combine linkage and association analyses to fine map QTL-Pal9, a QTL influencing levels of palmitic acid, an important class of saturated fatty acid. QTL-Pal9 was mapped to a 90-kb region, in which we identified a candidate gene, Zea mays fatb (Zmfatb), which encodes acyl-ACP thioesterase. An 11-bp insertion in the last exon of Zmfatb decreases palmitic acid content and concentration, leading to an optimization of the ratio of saturated to unsaturated fatty acids while having no effect on total oil content. We used three-dimensional structure analysis to explain the functional mechanism of the ZmFATB protein and confirmed the proposed model in vitro and in vivo. We measured the genetic effect of the functional site in 15 different genetic backgrounds and found a maximum change of 4.57 mg/g palmitic acid content, which accounts for ∼20–60% of the variation in the ratio of saturated to unsaturated fatty acids. A PCR-based marker for QTL-Pal9 was developed for marker-assisted selection of nutritionally healthier maize lines. The method presented here provides a new, efficient way to clone QTL, and the cloned palmitic acid QTL sheds lights on the genetic mechanism of oil biosynthesis and targeted maize molecular breeding

Size-Fractionated Filtration Combined with Molecular Methods Reveals the Size and Diversity of Picophytoplankton

In this study, flow cytometry (FCM) and size-fractionated filtration, together with high-throughput molecular sequencing methods (SM), were used to investigate picophytoplankton. A particle separation filter and a higher-throughput sequencing method were used to evaluate the composition of a euphotic zone of picophytoplankton—especially picoeukaryotic phytoplankton—in the Western Pacific, and the results of flow cytometry, which is a classic way to detect picophytoplankton, were used as a standard to evaluate the reliability of the results of the SMs. Within a water column of 200 m, six water depths (5, 25, 50, 113 (DCM), 150, and 200 m) were established. In order to further study the particle size spectra of the picophytoplankton, size-fractionated filtration was used to separate water samples from each water depth into three particle size ranges: 0.2–0.6, 0.6–1.2, and 1.2–2 μm. A total of 36 (6 × 3 × 2) samples were obtained through PCR amplification of the 18S rRNA V4 hypervariable region and 16S rRNA, which were biased toward phytoplankton plastids, and then high-throughput sequencing was performed. The estimation of the picophytoplankton diameter relied on forward scattering (FSC) through FCM. The estimation of the vertical distribution and diameter of the picophytoplankton using the SM was consistent with the results with FCM; thus, we believe that the estimation of picophytoplankton composition with the SM has value as a reference, although the size-fractionated filtration seemed to cause some deviations. In addition to Prochlorococcus and Synechococcus, the SM was used to evaluate the composition of picoeukaryotic phytoplankton, which mainly included Prymnesiophycea (Haptophyta) (38.15%), Cryptophyceae (Cryptophyta) (22.36%), Dictyochophyceae (Chrysophyta) (12.22%), and Mamiellophyceae (Chlorophyta) (3.31%). In addition, the SM also detected Dinophyceae (Dinoflagellata) (11.69%) sequences and a small number of Bacillariophyceae (Diatom) (1.64%) sequences, which are generally considered to have large particle sizes. The results of the SM also showed that the picoeukaryotic phytoplankton were not evenly distributed in the euphotic layer, and the vertical distributions of the different picoeukaryotic phytoplankton were different. An analysis of correlations with environmental factors showed that temperature was the main environmental factor controlling the vertical distribution of picophytoplankton

Ammonium Nitrogen Streamflow Transport Modelling and Spatial Analysis in Two Chinese Basins

Ammonium nitrogen (NH4+-N), which naturally arises from the decomposition of organic substances through ammonification, has a tremendous influence on local water quality. Therefore, it is vital for water quality protection to assess the amount, sources, and streamflow transport of NH4+-N. SPAtially Referenced Regressions on Watershed attributes (SPARROW), which is a hybrid empirical and mechanistic modeling technique based on a regression approach, can be used to conduct studies of different spatial scales on nutrient streamflow transport. In this paper, the load and delivery of NH4+-N in Poyang Lake Basin (PLB) and Haihe River Basin (HRB) were estimated using SPARROW. In PLB, NH4+-N load streamflow transport originating from point sources and farmland accounted for 41.83% and 32.84%, respectively. In HRB, NH4+-N load streamflow transport originating from residential land and farmland accounted for 40.16% and 36.75%, respectively. Hence, the following measures should be taken: In PLB, it is important to enhance the management of the point sources, such as municipal and industrial wastewater. In HRB, feasible measures include controlling the domestic pollution and reducing the usage of chemical fertilizers. In addition, increasing the vegetation coverage of both basins may be beneficial to their nutrient management. The SPARROW models built for PLB and HRB can serve as references for future uses for different basins with various conditions, extending this model’s scope and adaptability

Ammonium Nitrogen Streamflow Transport Modelling and Spatial Analysis in Two Chinese Basins

Ammonium nitrogen (NH4+-N), which naturally arises from the decomposition of organic substances through ammonification, has a tremendous influence on local water quality. Therefore, it is vital for water quality protection to assess the amount, sources, and streamflow transport of NH4+-N. SPAtially Referenced Regressions on Watershed attributes (SPARROW), which is a hybrid empirical and mechanistic modeling technique based on a regression approach, can be used to conduct studies of different spatial scales on nutrient streamflow transport. In this paper, the load and delivery of NH4+-N in Poyang Lake Basin (PLB) and Haihe River Basin (HRB) were estimated using SPARROW. In PLB, NH4+-N load streamflow transport originating from point sources and farmland accounted for 41.83% and 32.84%, respectively. In HRB, NH4+-N load streamflow transport originating from residential land and farmland accounted for 40.16% and 36.75%, respectively. Hence, the following measures should be taken: In PLB, it is important to enhance the management of the point sources, such as municipal and industrial wastewater. In HRB, feasible measures include controlling the domestic pollution and reducing the usage of chemical fertilizers. In addition, increasing the vegetation coverage of both basins may be beneficial to their nutrient management. The SPARROW models built for PLB and HRB can serve as references for future uses for different basins with various conditions, extending this model’s scope and adaptability

Propensity Score Matching Analysis of the Influence of Waiting Time Satisfaction on Community Resident’s Satisfaction With Medical Institutions: An Extensive Survey of Outpatient Population in Shantou City of Southern China

Objective: This study was designed to perform a nuanced analysis of the multifaceted association between community residents’ satisfaction and their perceived satisfaction concerning the visit duration at medical facilities, that could be harnessed to enhance and streamline the process of hierarchical diagnosis and treatment, thereby augmenting healthcare outcomes and patient experiences. Methods: Respondents who had utilized services from medical institutions were invited to fill out questionnaires by scanning QR codes. Additionally, surveys also distributed questionnaires through WeChat groups of community residents in densely populated areas of the community, as well as WeChat groups for patients who had previously visited local hospitals. To balance differences between groups, propensity score matching was applied to analyze the contrast between residents satisfied and dissatisfied with their medical visits. After eliminating the interference of confounding factors, a comparative analysis was conducted on the relationship between resident satisfaction and medical institution experience.After eliminating the interference of confounding factors, a comparative analysis was conducted to delve deeply into the relationship between residents’ satisfaction and their experiences at medical facilities. Results: The study incorporated a large dataset encompassing 2356 community residents. Upon successful propensity score matching, logistic regression analysis elucidated several determinants of overall resident satisfaction. Notably, the grade of the medical institution (χ 2  = 8.226, P  < .05), satisfaction with the time invested in the registration process (χ 2  = 11.04, P  < .05), satisfaction with the waiting duration for consultation (χ 2  = 15.759, P  < .05), and satisfaction with the travel time to the hospital (χ 2  = 45.157, P  < .05) each exerted significant influence on the holistic satisfaction of residents with their medical experience. Conclusion: Factors such as the grade of the medical institution, satisfaction related to registration and waiting durations, and travel time to the hospital emerged as crucial determinants shaping community residents’ holistic satisfaction with their medical encounters. These findings underscore the exigency for strategic allocation and optimization of medical resources, refinement of the classification system, and enhancement of public health education on the graded diagnosis and treatment schema. The study also demonstrates the value of employing advanced propensity score matching and predictive modelling techniques in health services research

Response of Size-Fractionated Chlorophyll a to Upwelling and Kuroshio in Northeastern South China Sea

The variability of size-fractionated chlorophyll a (Chl a) biomass and related environmental variables was investigated in a survey conducted in the northeastern South China Sea (NESCS), to assess their responses to upwelling, Kuroshio, and nutrients in the summer of 2017. The depth-weighted total Chl a concentration varied from 0.057 to 0.496 &mu;g/L. The contribution of size-fractionated Chl a to total Chl a biomass was determined, with the contributions of pico-Chl a (0.2&ndash;2 &mu;m), nano-Chl a (2&ndash;20 &mu;m), and micro-Chl a (&gt;20 &mu;m) found to be 52.87%, 38.54%, and 8.59%, respectively. We found that nano-Chl a contributes more to total-Chl a than pico-Chl a in areas affected by upwelling. In addition, the results indicated an upward shift in the deep chlorophyll maximum (DCM) content in the upwelling area and the Kuroshio intrusion area. The Chl a biomass was increased in the physical process. Overall, correlation analysis showed that environmental variables (temperature, salinity, phosphate, silicate, nitrate, nitrite, ammonium) significantly influenced the phytoplankton biomass. However, physical processes determined the changes in environmental variables, with upwelling and Kuroshio being the main factors regulating the distribution of Chl a

Response of Size-Fractionated Chlorophyll <i>a</i> to Upwelling and Kuroshio in Northeastern South China Sea

The variability of size-fractionated chlorophyll a (Chl a) biomass and related environmental variables was investigated in a survey conducted in the northeastern South China Sea (NESCS), to assess their responses to upwelling, Kuroshio, and nutrients in the summer of 2017. The depth-weighted total Chl a concentration varied from 0.057 to 0.496 μg/L. The contribution of size-fractionated Chl a to total Chl a biomass was determined, with the contributions of pico-Chl a (0.2–2 μm), nano-Chl a (2–20 μm), and micro-Chl a (>20 μm) found to be 52.87%, 38.54%, and 8.59%, respectively. We found that nano-Chl a contributes more to total-Chl a than pico-Chl a in areas affected by upwelling. In addition, the results indicated an upward shift in the deep chlorophyll maximum (DCM) content in the upwelling area and the Kuroshio intrusion area. The Chl a biomass was increased in the physical process. Overall, correlation analysis showed that environmental variables (temperature, salinity, phosphate, silicate, nitrate, nitrite, ammonium) significantly influenced the phytoplankton biomass. However, physical processes determined the changes in environmental variables, with upwelling and Kuroshio being the main factors regulating the distribution of Chl a

Effects of typhoon Roke and Haitang on phytoplankton community structure in northeastern South China sea

The influence of typhoon and Kuroshio intrusion process on the natural phytoplankton assemblages in the northeastern South China Sea (neSCS) was examined during a cruise in summer 2017. One hundred ninety-six seawater samples were collected and analyzed in the neSCS. In total, 299 species were identified belonging to 82 genera, mostly dominated by Bacillariophyta (159), followed by Dinophyta (132), Cyanophyta (4) and Chrysophyta (4). Among all, Thalassionema nitzschioides, Thalassionema frauenfeldii, Thalassiosira minima, in Bacillariophyta, Prorocentrum lenticulatum, Prorocentrum compressum in Dinophyta, and Trichodesmium thiebautii, in the Cyanophyta were the most dominated species, respectively. Correlation analysis shows compared with other groups Bacillariophyta was mostly influenced by silicate, whereas, Dinophyta and Cyanophyta showed significant correlation with temperature, salinity, phosphate, and nitrate. After the typhoon, the higher abundance of Dinophyta was observed, whereas it was lower in case of Bacillariophyta and Cyanophyta, shows typhoon “Roke“ and ”Haitang” had a significant influence on the phytoplankton assemblages, which could be manifested by the variations of total phytoplankton abundance in the surface water of neSCS. Overall, our present study provides the latest in-depth information about how the environmental factors influencing the phytoplankton density and diversity in the neSCS during summer

Effects of shade treatments on photosynthetic characteristics, chloroplast ultrastructure, and physiology of Anoectochilus roxburghii.

Anoectochilus roxburghii was grown under different shade treatments-50%, 30%, 20%, and 5% of natural irradiance-to evaluate its photosynthetic characteristics, chloroplast ultrastructure, and physiology. The highest net photosynthetic rates and stomatal conductance were observed under 30% irradiance, followed in descending order by 20%, 5%, and 50% treatments. As irradiance decreased from 50% to 30%, electron transport rate and photochemical quenching increased, while non-photochemical quenching indexes declined. Reductions in irradiance significantly increased Chl a and Chl b contents and decreased Chl a/b ratios. Chloroplast ultrastructure generally displayed the best development in leaves subjected to 30% irradiance. Under 50% irradiance, leaf protein content remained relatively stable during the first 20 days of treatment, and then increased rapidly. The highest peroxidase and superoxide dismutase levels, and the lowest catalase activities, were observed in plants subjected to the 50% irradiance treatment. Soluble sugar and malondialdehyde contents were positively correlated with irradiance levels. Modulation of chloroplast development, accomplished by increasing the number of thylakoids and grana containing photosynthetic pigments, is an important shade tolerance mechanism in A. roxburghii