ROS as a key player in quinolone antibiotic stress on Arabidopsis thaliana: From the perspective of photosystem function, oxidative stress and phyllosphere microbiome.

With the increasing use of antibiotics, their ecological impacts have received widespread attention. However, research on the toxicity of quinolone antibiotics is still limited, especially regarding the oxidative stress and phyllosphere of plants. In this study, the toxic effects of enrofloxacin, norfloxacin, and levofloxacin on Arabidopsis thaliana and their underlying mechanisms were investigated. The toxicity of the three quinolone antibiotics decreased in the following order: enrofloxacin > norfloxacin > levofloxacin. Physiological cellular changes, such as plasmolysis and chloroplast swelling, were observed using electron microscopy. Photosynthetic efficiency was inhibited with a decline in the effective photochemical quantum yield of photosystem II (Y(II)) and non-photochemical quenching (NPQ), indicating that quinolone antibiotics might reduce light energy conversion efficiency and excess light energy dissipation. Oxidative stress occurred in A. thaliana after quinolone antibiotic treatment, with an increase in reactive oxygen species (ROS) levels and malondialdehyde (MDA) content. High ROS levels stimulated the over-expression of superoxide-responsive genes for self-protection. Structural equation modeling (SEM) analysis showed that photosynthesis inhibition and cellular damage caused by oxidative stress were critical factors for growth inhibition, suggesting that the antioxidant response activated by ROS might be a potential mechanism. Furthermore, the diversity of the phyllospheric microbial communities decreased after enrofloxacin exposure. Additionally, specific microbes were preferentially recruited to the phyllosphere because of the higher ROS levels.

[Morphology and function of platelets stored in modified platelet additive solution at low temperature].

The aim of study was to evaluate the function of modified platelet additive solution (PAS-IIIM) with trehalose as a substitute of plasma for the storage of platelet concentrates at low temperature (10 degrees C). Apheresis platelets from 6 donors were divided and added with different media (group A: 100% plasma; group B: 70% PAS-IIIM/30% plasma; group C: 100% plasma/trehalose). Groups A, B, C were stored at 10 degrees C, 22 degrees C and -85 degrees C separately. In addition, group D (platelet concentrates stored with 100% plasma at 4 degrees C) was set up as control group for scan electronmicroscopy. The samples of each platelets were collected on day 0, 1, 5, 7 and 9 after storage respectively, while samples of platelets stored at -85 degrees C (group C) were collected on day 20 after storage. CD62p, hypotonic shock response (HSR), platelet aggregation, lactic dehydrogenase (LDH) and morphology of platelets were evaluated. The results showed that the expressions of CD62p in groups A and B increased in a time-dependent manner, but HSR and platelet aggregations decreased. The expression of CD62p, LDH release, and platelet aggregation in group A were significant higher than that in group B (p < 0.05). HSR in group A was significant lower than that in group B (p < 0.05). LDH release was significant high in samples of group C and the expression of CD62p was lower than that in other two groups (p < 0.05). It is concluded that the protective effects of 70% PAS-IIIM/30% plasma (10 degrees C) and plasma platelets (22 degrees C) on morphology of platelets are similar, but better than those of plasma platelets (4 degrees C) and plasma/trehalose (-85 degrees C). In short, PAS-IIIM serves as a good substitute of plasma for platelet storage, and protects the chilled platelets.

[Report on difficulty in blood group identification due to anti-H antibody in three cases].

Anti-H antibody belongs to IgM type cold antibody, which often induces the unconformity of positive and reverse typing and leads to the difficulty in clinical blood typing. Anti-H antibody was found during identification of the counter blood group in 3 cases. The antibody was found to be active at 37 degrees C, room temperature and 4 degrees C when determined by blood group serology, and was finally analyzed to be IgM. It is suggested that not to give erythrocytes of O group unreasoningly to blood recipient of AB group during emergent moment, but instead, to give same type of blood. If there was no same type of blood during urgent events, O type erythrocytes could be employed after being matched by saline centrifuging with host side coincidence and screened by incomplete method. In this case, anti-H antibody leading to adverse-reaction in blood transfusion should be prevented.