Natural Variation in Arabidopsis Cvi-0 Accession Reveals an Important Role of MPK12 in Guard Cell CO2 Signaling

Plant gas exchange is regulated by guard cells that form stomatal pores. Stomatal adjustments are crucial for plant survival; they regulate uptake of CO2 for photosynthesis, loss of water, and entrance of air pollutants such as ozone. We mapped ozone hypersensitivity, more open stomata, and stomatal CO2-insensitivity phenotypes of the Arabidopsis thaliana accession Cvi-0 to a single amino acid substitution in MITOGEN-ACTIVATED PROTEIN (MAP) KINASE 12 (MPK12). In parallel, we showed that stomatal CO2-insensitivity phenotypes of a mutant cis (CO2-insensitive) were caused by a deletion of MPK12. Lack of MPK12 impaired bicarbonate-induced activation of S-type anion channels. We demonstrated that MPK12 interacted with the protein kinase HIGH LEAF TEMPERATURE 1 (HT1)-a central node in guard cell CO2 signaling-and that MPK12 functions as an inhibitor of HT1. These data provide a new function for plant MPKs as protein kinase inhibitors and suggest a mechanism through which guard cell CO2 signaling controls plant water management.</p

Indoor air quality-induced respiratory symptoms of a hospital staff in Iran

The ambient air of hospitals contains a wide range of biological and chemical pollutants. Exposure to these indoor pollutants can be hazardous to the health of hospital staff. This study aims to evaluate the factors affecting indoor air quality and their effect on the respiratory health of staff members in a busy Iranian hospital. We surveyed 226 hospital staff as a case group and 222 office staff as a control group. All the subjects were asked to fill in a standard respiratory questionnaire. Pulmonary function parameters were simultaneously measured via a spirometry test. Environmental measurements of bio-aerosols, particulate matter, and volatile organic compounds in the hospital and offices were conducted. T-tests, chi-square tests, and multivariable logistic regressions were used to analyze the data. The concentration of selected air pollutants measured in the hospital wards was more than those in the administrative wards. Parameters of pulmonary functions were not statistically significant (p > 0.05) between the two groups. However, respiratory symptoms such as coughs, phlegm, phlegmatic coughs, and wheezing were more prevalent among the hospital staff. Laboratory staff members were more at risk of respiratory symptoms compared to other occupational groups in the hospital. The prevalence of sputum among nurses was significant, and the odds ratio for the presence of phlegm among nurses was 4.61 times greater than office staff (p = 0.002). The accumulation of indoor pollutants in the hospital environment revealed the failure of hospital ventilation systems. Hence, the design and implementation of an improved ventilation system in the studied hospital is recommended