Improving Occupational Exposure Assessment for Pesticide Epidemiological Studies
Project aims to validate exposure assessment methods in pesticide studies by using existing data, biomonitoring, and group comparisons. Key outcomes include validating EA methods against urine pesticide metabolites and comparing reliability of individual vs. grouped methods.
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Phloem Loading & Unloading by Subhamita Das
Introduction Phloem, a vascular tissue in plants, is responsible for transporting nutrients, primarily sugars (such as sucrose), from the site of photosynthesis (usually the leaves) to various parts of the plant, including roots, stems, flowers, and fruits. This long-distance transportation of sugars occurs through a process known as phloem loading and unloading. These mechanisms ensure that plants efficiently distribute energy sources to support growth, development, and metabolic activities in different tissues throughout their entire structure.
Loading 1.Symplastic Loading: In symplastic loading, sugars move through plasmodesmata, the microscopic channels connecting adjacent plant cells. Sucrose and other nutrients pass from mesophyll cells to companion cells and then into the sieve tube elements through these interconnected pathways. 2.Apoplastic Loading: Apoplastic loading involves the movement of sugars through the cell walls and intercellular spaces. Sugars are first transported into the apoplast of the mesophyll cells and then reabsorbed into the sieve elements via specific transporter proteins located in the plasma membrane of companion cells.
Unloading 1.Symplastic Unloading: In symplastic unloading, sugars move through plasmodesmata from the sieve tube elements to the sink cells. These sugars can then be utilized for various processes like growth or converted into storage compounds. 2.Apoplastic Unloading: In apoplastic unloading, the sugars are released into the apoplast surrounding the sink cells. They are subsequently taken up by the sink cells through specific transporter proteins located in their plasma membranes.
