Bacillus amyloliquefaciens PMB05 Increases Resistance to Bacterial Wilt by Activating Mitogen-Activated Protein Kinase and Reactive Oxygen Species Pathway Crosstalk in Arabidopsis thaliana

Bacterial wilt caused by Ralstonia solanacearum can infect many crops, causing significant losses worldwide. The use of beneficial microorganisms is considered a feasible method for controlling this disease. Our previous study showed that Bacillus amyloliquefaciens PMB05 can control bacterial wilt through intensifying immune signals triggered by a pathogen-associated molecular pattern (PAMP) from R. solanacearum. It is still uncertain whether induction of the mitogen-activated protein kinase (MAPK) pathway during PAMP-triggered immunity (PTI) is responsible for enhancing disease resistance. To gain more insights on how the presence of PMB05 regulates PTI signaling, its association with the MAPK pathway was assayed. Our results showed that the activation of MPK3/6 and expression of wrky22 upon treatment with the PAMP, PopW, was increased during co-treatment with PMB05. Moreover, the disease resistance conferred by PMB05 to bacterial wilt was abolished in mekk1, mkk5, and mpk6 mutants. To determine the relationship between the MAPK pathway and plant immune signals, the assay on reactive oxygen species (ROS) generation and callose deposition showed that only the ROS generation was strongly reduced in these mutants. Because ROS generation is highly correlated with RbohD, the results revealed that the effects of PMB05 on both PopW-induced ROS generation and disease resistance to bacterial wilt were eliminated in the rbohD mutant, suggesting that the generation of ROS is also required for PMB05-enhanced disease resistance. Taken together, we concluded that the crosstalk between the initiation of ROS generation and further activation of the MAPK pathway is necessary when PMB05 is used to improve disease resistance to bacterial wilt. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Labiolingual and mesiodistal positioning of maxillary permanent incisors during the eruption process

This study aimed to establish radiographical parameters concerning the tipping, the labiolingual positioning and the angulation of the maxillary permanent incisors in the mixed dentition. Three groups of 20 cephalograms and 20 orthopantomographic radiographs taken from children aging from 7 to 12 years old, with normal occlusion were compared. The Group I presented only the eruption of the central permanent incisors, the Group II presented both the central and lateral permanent incisors and the Group III presented central, lateral incisors and permanent canine teeth. The tipping and the labiolingual positioning were measured, respectively, using U1/PP and U1<-->AVERT. Mesiodistally, the angles between the teeth axis and the line that touched the lower border of the orbit in the orthopantomographic radiographs were measured. The mean values of tipping, labiolingual positioning and angulation of the central and lateral incisors obtained from Groups I, II and III were respectively 112 degrees, 1.2 mm, 90.4 degrees and 91.7 degrees; 112 degrees, 2.6 mm, 89.5 degrees and 96.8 degrees and 114 degrees, 2.7 mm, 87.4 degrees and 92.6 degrees. The tipping levels were similar for all groups, the mean values of the labiolingual positioning were significantly different at 5% when Group I was compared to both Groups II and III. And the mean values of the angulation were significantly different 5% for the central incisors between Groups I and III, and at 1% for the lateral incisors between Groups I and II, and, II and III.

Transfer of methohexital across the perfused human placenta

STUDY OBJECTIVES

To evaluate the transfer properties of methohexital and the influence of protein binding using the in vitro human placental perfusion model.

DESIGN

Fresh term human placentae from healthy parturients were perfused bidirectionally via a cannulated fetal chorionic artery and vein and needles placed into the maternal intervillous space. Maternal-to-fetal (M-->F) and fetal-to-maternal (F-->M) transfer and ultimate distribution of methohexital was investigated using a closed (recirculating) placental perfusion model.

SETTING

Obstetric anesthesia laboratories of two university medical centers.

PATIENTS

No patient participation occurred as placentae were obtained after delivery.

INTERVENTION

M-->F and F-->M transfer of methohexital was compared in vitro in perfusates with equal protein concentrations (2 g/100 mL in both perfusates) or albumin-simulated physiologic protein binding concentrations (maternal 8 g/100 mL; fetal 4 g/100 mL).

MEASUREMENTS AND MAIN RESULTS

Data obtained consisted of measurements of methohexital and antipyrine concentrations by high-performance liquid chromatography. Glucose and lactate concentrations and perfusate loss were measured to assess placental viability. Methohexital protein binding was assessed at 2, 4, and 8 g/100 mL of albumin by equilibrium dialysis. The transfer index of 0.83 +/- 0.11 for the M-->F perfusions was significantly greater (p < or = 0.05) than in the F-->M direction (0.61 +/- 0.04) when albumin concentration was equal in both perfusates. This transfer asymmetry disappeared when albumin concentrations simulating maternal (8 g/100 mL) versus fetal (4 g/100 mL) protein concentrations in the perfusate were used (M-->F 0.87 +/- 0.12 and F-->M 0.95 +/- 0.11).

CONCLUSION

Methohexital readily crosses the placenta in both directions. Protein binding has significant effects on the degree of transfer of methohexital at any time when compared with antipyrine and its ultimate fetal/maternal distribution.