Evaluating the climatic impacts on dryland crop growth using multi-source datasets across Australia

University of Technology Sydney. Faculty of Science.The rainfed cropland belt in Australia is of great importance to the world grain market but has the highest climate variability of all such regions globally. This thesis aims to quantify the spatial temporal climatic impacts on crop productivity, crop phenology and cropland photosynthesis activities across the Australian rainfed cropland belts using multiple source of observed datasets. The literature review on climate-crop growth relationship called for a future agenda on integrated climate driving factor employment, crop phenology and photosynthesis response focus, multiple source of datasets engagement, and bottom-up approaches for agricultural adaptation. Consistent findings from the three empirical studies in this thesis, which focused on different broad angles of the crop response, indicate that: (1) August and September are the optimum trigger months to spatially predict agricultural annual yield across the rainfed cropland belts in Australia; (2) two critical 8-day periods, beginning on day of the year (DoY) 257 (in September) and 289 (in October), were identified as the key ‘windows’ of crop growth variation that arose from the variability in climate and land surface temperature. (3) there was a seasonal hysteresis of crop photosynthesis activities in response to surface temperature change throughout the winter crop growing season in Australia. The optimum surface temperature range for satellite observed photosynthesis activity were identified as16.6-17.6 °C during August. This thesis systematically assessed the climatic impacts on crop growth across the Australian rainfed cropland belts. Practically, it provides new opportunities for large-scale cropland heat and water stress detection and can serve as an early warning system for agricultural adaptation in broad-acre rainfed cropping practices. Theoretically, it offers a fresh understanding for analyses of the climate-crop growth relationship across diverse spatial-temporal scales

The Mechanism of ATP-Dependent Allosteric Protection of Akt Kinase Phosphorylation

SummaryKinases use ATP to phosphorylate substrates; recent findings underscore the additional regulatory roles of ATP. Here, we propose a mechanism for allosteric regulation of Akt1 kinase phosphorylation by ATP. Our 4.7-μs molecular dynamics simulations of Akt1 and its mutants in the ATP/ADP bound/unbound states revealed that ATP occupancy of the ATP-binding site stabilizes the closed conformation, allosterically protecting pT308 by restraining phosphatase access and key interconnected residues on the ATP→pT308 allosteric pathway. Following ATP→ADP hydrolysis, pT308 is exposed and readily dephosphorylated. Site-directed mutagenesis validated these predictions and indicated that the mutations do not impair PDK1 and PP2A phosphatase recruitment. We further probed the function of residues around pT308 at the atomic level, and predicted and experimentally confirmed that Akt1H194R/R273H double mutant rescues pathology-related Akt1R273H. Analysis of classical Akt homologs suggests that this mechanism can provide a general model of allosteric kinase regulation by ATP; as such, it offers a potential avenue for allosteric drug discovery

Identification of novel urine proteomic biomarkers for high stamina in high-altitude adaptation

Introduction: We aimed to identify urine biomarkers for screening individuals with adaptability to high-altitude hypoxia with high stamina levels. Although most non-high-altitude natives experience rapid decline in physical ability when ascending to high altitudes, some individuals with high-altitude adaptability continue to maintain high endurance levels.Methods: We divided the study population into two groups: the LC group (low change in endurance from low to high altitude) and HC group (high change in endurance from low to high altitude). We performed blood biochemistry testing for individuals at high altitudes and sea level. We used urine peptidome profiling to compare the HH (high-altitude with high stamina) and HL (high-altitude with low stamina) groups and the LC and HC groups to identify urine biomarkers.Results: Routine blood tests revealed that the concentration of white blood cells, lymphocytes and platelets were significantly higher in the HH group than in the HL group. Urine peptidome profiling showed that the proteins ITIH1, PDCD1LG2, NME1-NME2, and CSPG4 were significantly differentially expressed between the HH and HL groups, which was tested using ELISA. Urine proteomic analysis showed that LRG1, NID1, VASN, GPX3, ACP2, and PRSS8 were urine proteomic biomarkers of high stamina during high-altitude adaptation.Conclusion: This study provides a novel approach for identifying potential biomarkers for screening individuals who can adapt to high altitudes with high stamina

Spatially Weighted Estimation of Broadacre Crop Growth Improves Gap-Filling of Landsat NDVI

Seasonal climate is the main driver of crop growth and yield in broadacre grain cropping systems. With a 40-year record of 30 m resolution images and 16-day revisits, the Landsat satellite series is ideal for producing long-term records of remotely sensed phenology to build understanding of how climate affects crop growth. However, the time-series of Landsat images exhibits gaps caused by cloud cover, which is common in wet periods when crops reach maximum growth. We propose a novel spatial–temporal approach to gap-filling that avoids data fusion. Crop growth curve estimation is used to perform temporal smoothing and incorporation of spatial weights allows spatial smoothing. We tested our approach using Landsat NDVI data acquired for an 8000 ha study area in Western Australia using a train/test approach where 157 available Landsat-7 images between 2013 and 2019 were used to train the model, and 95 at least 80% cloud-free Landsat-8 images from the same period were used to test its performance. We found that compared to nonspatial estimation, use of spatial weights in growth curve estimation improved correlation between observed and predicted NDVI by 75%, MAE by 31% and RMSE by 75%. For cropland, the correlation is improved by 58%, the MAE by 36% and the RMSE by 76%. We conclude that spatially weighted estimation of crop growth curves can be used to fill spatial and temporal gaps in Landsat NDVI for the purpose of within-field monitoring. Our approach is also applicable to other data sources and vegetation indices

Research Progress of Organic Corrosion Inhibitors in Metal Corrosion Protection

Metal materials are vulnerable to corrosion in the process of production and service, which often leads to serious disasters, including the decline of the performance of metal components and the shortened service life, and even causes catastrophic accidents and ecological damage. Adding a certain amount of corrosion inhibitors (CIs) to the corrosive medium is a simple, efficient, and economical anti-corrosion method to slow down and restrain the corrosion of metal materials. Organic corrosion inhibitors (OCIs) are considered to have good application prospects and are widely used for surface anti-corrosion of metal materials, as they generally have advantages such as good metal adsorption, low oxidation resistance, good thermal and chemical stability, and green environmental protection. This paper systematically summarized some major OCIs, including alkyl chains, imidazoles, and pyridines, and their structural characteristics, as well as the action mechanism of OCIs. Moreover, this paper discusses some natural compounds used as environmentally friendly CIs and provides a prospect for the development trend of OCIs

Silver Nanoclusters-Based Fluorescence Assay of Protein Kinase Activity and Inhibition

A simple and sensitive fluorescence method for monitoring the activity and inhibition of protein kinase (PKA) has been developed using polycytosine oligonucleotide (dC₁₂)-templated silver nanoclusters (Ag NCs). Adenosine-5′-triphosphate (ATP) was found to enhance the fluorescence of Ag NCs, while the hydrolysis of ATP to adenosine diphosphate (ADP) by PKA decreased the fluorescence of Ag NCs. Compared to the existing methods for kinase activity assay, the developed method does not involve phosphorylation of the substrate peptides, which significantly simplifies the detection procedures. The method exhibits high sensitivity, good selectivity, and wide linear range toward PKA detection. The inhibition effect of kinase inhibitor H-89 on the activity of PKA was also studied. The sensing protocol was also applied to the assay of drug-stimulated activation of PKA in HeLa cell lysates

A conserved megaprotein-based molecular bridge critical for lipid trafficking and cold resilience.

Cells adapt to cold by increasing levels of unsaturated phospholipids and membrane fluidity through conserved homeostatic mechanisms. Here we report an exceptionally large and evolutionarily conserved protein LPD-3 in C. elegans that mediates lipid trafficking to confer cold resilience. We identify lpd-3 mutants in a mutagenesis screen for genetic suppressors of the lipid desaturase FAT-7. LPD-3 bridges the endoplasmic reticulum (ER) and plasma membranes (PM), forming a structurally predicted hydrophobic tunnel for lipid trafficking. lpd-3 mutants exhibit abnormal phospholipid distribution, diminished FAT-7 abundance, organismic vulnerability to cold, and are rescued by Lecithin comprising unsaturated phospholipids. Deficient lpd-3 homologues in Zebrafish and mammalian cells cause defects similar to those observed in C. elegans. As mutations in BLTP1, the human orthologue of lpd-3, cause Alkuraya-Kucinskas syndrome, LPD-3 family proteins may serve as evolutionarily conserved highway bridges critical for ER-associated non-vesicular lipid trafficking and resilience to cold stress in eukaryotic cells