Assessment of the elementary school students' schoolbag weight in the urban environment in Poland: A cross-sectional study carried out as a part of the 'Lightweight Schoolbag' and 'Let's Get the Kids Moving' projects.

BACKGROUND: Carrying a properly weighted schoolbag is an important factor in preventing the occurrence of muscular skeletal disorder in early school age children. OBJECTIVE: The purpose of this cross- sectional observational study was to examine the schoolbag weight and to determine the percentage of children were carrying overloaded schoolbag. METHODS: The study group included pupils from five primary public schools in Wroclaw, Poland. Anthropometrical measurements such body weight (BW) and height were conducted on 650 children (51.1% of boys). Children's age, gender, Cole's Index was juxtaposed with schoolbag weight. The mean age of the examined students was 8.7±0.8 years (range 7 to 10 years). RESULTS: The mean schoolbags weight was 3.7±0.92 kg, which represented 13.0±3.8% of pupils' BW. The percentage of pupils carry the schoolbags weighing more than 10% of their BW was 77.9%. More than a quarter of Polish children carry school backpack above 15% of their BW. The majority (96.8%) had schoolbags which may be carried on both shoulders. A significant negative correlation was observed between relative schoolbag weight and Cole's Index (rho = -0.44, p < 0.05). CONCLUSIONS: The problem of overloaded schoolbags among elementary school children was frequent. Pupils ought to be educated in the proper packing of their school backpacks. Additionally, parents and teachers should pay attention regarding the contents carried by children in their respective schoolbags.

EPIP as an abscission promoting agent in the phytohormonal pathway.

Understanding the mechanisms underlying the activation of the abscission zone (AZ) responsible for organ separation from plant body in crop species will help improve their yielding and economic importance. Special attention has been given recently to the role of the INFLORESCENCE DEFICIENT IN ABSCISSION protein, particularly its functional fragment, EPIP peptide. Its stimulatory effect on abscission in different crops has been demonstrated. Recently we described the role of EPIP in the redox, lipid, and pectin-related events taking place in AZ of Lupinus luteus flowers, which undergo massive abscission in natural conditions. To further examine EPIP contribution in AZ functioning, here, we analyze its impact on the ultrastructural changes, synthesis of two hormonal abscission stimulators - abscisic acid (ABA) and ethylene (ET), and the appearance of phosphoproteins. As our results show, the response of flower AZ to exogenous EPIP involves the induction of distinct modifications related to the one hand with upregulation of cell activity but on the other hand degradation processes and possible autophagy. Furthermore, the EPIP stimulated biosynthesis pathways of ABA and ET precisely in AZ cells. In addition, progressive phosphorylation of proteins has been observed under EPIP influence. The highly accumulated ones were identified as those, related to primary metabolism and reactive oxygen species homeostasis, and their role in abscission has been discussed. To summarizing, the presented detailed description of EPIP action in AZ cells in combination with our previous data offers new insights into its regulatory function and provides opportunities to counteract excessive flower abscission in lupine.

EPIP-Evoked Modifications of Redox, Lipid, and Pectin Homeostasis in the Abscission Zone of Lupine Flowers.

Yellow lupine is a great model for abscission-related research given that excessive flower abortion reduces its yield. It has been previously shown that the EPIP peptide, a fragment of LlIDL (INFLORESCENCE DEFICIENT IN ABSCISSION) amino-acid sequence, is a sufficient molecule to induce flower abortion, however, the question remains: What are the exact changes evoked by this peptide locally in abscission zone (AZ) cells? Therefore, we used EPIP peptide to monitor specific modifications accompanied by early steps of flower abscission directly in the AZ. EPIP stimulates the downstream elements of the pathway-HAESA and MITOGEN-ACTIVATED PROTEIN KINASE6 and induces cellular symptoms indicating AZ activation. The EPIP treatment disrupts redox homeostasis, involving the accumulation of H2O2 and upregulation of the enzymatic antioxidant system including superoxide dismutase, catalase, and ascorbate peroxidase. A weakening of the cell wall structure in response to EPIP is reflected by pectin demethylation, while a changing pattern of fatty acids and acyl lipids composition suggests a modification of lipid metabolism. Notably, the formation of a signaling molecule-phosphatidic acid is induced locally in EPIP-treated AZ. Collectively, all these changes indicate the switching of several metabolic and signaling pathways directly in the AZ in response to EPIP, which inevitably leads to flower abscission.