Digital anatomical features of morphological development in C2-C7 neurocentral synchondrosis in children aged 1-6 years: a retrospective study of CT images.

BACKGROUND: With the continuous improvement of diagnosis and treatment technology for cervical spine-related diseases in children at home and abroad, the demand for exploring the developmental anatomy and function of children's cervical spine of different ages is increasing. So the aim of this study was to investigate the changes of anatomical indicators in neurocentral synchondrosis (NCS) of C2-C7 with age and the developmental characteristics of different vertebrae in children aged 1-6 years old. METHOD: A retrospective collection of 160 cases of normal cervical spine CT images of children aged 1-6 years old in provincial tertiary hospitals, according to the age group of 1-year-old into 6 groups. The original data of continuously scanned cervical spine tomography images were imported into Mimics16.0 software, under the two-dimensional image window, selected the measurement tool under the Measurements toolbar to measure and statistically analyzed the anatomical indicators such as cross diameter, sagittal diameter, height, perimeter and area of NCS in the C2-C7 segment of the cervical spine on the coronal plane and cross-section. RESULTS: There was no significant difference in the anatomical indexes of cervical spine NCS in children compared with the left and right sides of the same vertebrae (P > 0.05). The same cervical spine generally had differences between the age groups of 1-4 years old and 5-6 years old (P < 0.05).The transverse diameter and circumference gradually decreased with age; the sagittal diameter and height showed a slight increase trend; there was a maximum area at 2 years of age. In different cervical vertebrae of the same age group, the NCS values of C3, C4, and C5 varied greatly, which showed that the ossification process of cervical cartilage was faster than that at the upper and lower ends. There were obvious differences between C2 and the rest of the cervical vertebral segments' NCS ossification process. C7 was also very different from the rest of the cervical vertebrae segments, presumably more similar to the thoracic spine. CONCLUSIONS: The anatomical indexes of C2-C7 NCS in children have obvious developmental regularities at different ages, and there are also regularities between cervical segments.

Digital anatomical features of morphological development in the atlantoaxial synchondroses in children aged 1 to 6 years old: a retrospective study of CT images.

OBJECTIVE: To investigate the anatomical indexes and anatomical positional indexes of the atlantoaxial synchondroses in normal Chinese Han children aged 1-6 years, and to analyze the changing law of the atlantoaxial cartilage union with the growth and development of age and its influence on the atlantoaxial ossification in children. METHODS: A retrospective collection of CT imaging of 160 cases of normal cervical spine in children aged 1 to 6 years old was conducted. The cases were divided into six age groups, with each group representing a one-year age range. Measure the morphological anatomical indicators and anatomical positional indicators of the atlantoaxial synchondroses. Record and statistically analyze the measurements of each indicator. RESULTS: Measurements were taken on various parameters of the atlantoaxial synchondroses. TD, SD, height, area, and perimeter all gradually decreased among the groups. Distance between bilateral atlantal anterolateral synchondroses increased gradually from Group A to Group F, while the angle formed along the long axis in the cross-section showed a decreasing trend. Distance between the axoid dentolateral synchondroses and between the neurocentral synchondroses increased gradually from Group A to Group F, with the angle value in the cross-section showing a gradual decrease, and distance from the odontoid apex increasing from Group A to Group F. CONCLUSIONS: The atlantoaxial synchondroses gradually decrease in size with age, and ossification levels increase with age, with faster ossification occurring during a 1-2 years-old period. The anterolateral synchondroses, dentolateral synchondroses, and neurocentral synchondroses all gradually ossify towards the lateral direction with increasing age.

Persulfidation maintains cytosolic G6PDs activity through changing tetrameric structure and competing cysteine sulfur oxidation under salt stress in Arabidopsis and tomato.

Glucose-6-phosphate dehydrogenases (G6PDs) are essential regulators of cellular redox. Hydrogen sulfide (H2 S) is a small gasotransmitter that improves plant adaptation to stress; however, its role in regulating G6PD oligomerization to resist oxidative stress remains unknown in plants. Persulfidation of cytosolic G6PDs was analyzed by mass spectrometry (MS). The structural change model of AtG6PD6 homooligomer was built by chemical cross-linking coupled with mass spectrometry (CXMS). We isolated AtG6PD6C159A and SlG6PDCC155A transgenic lines to confirm the in vivo function of persulfidated sites with the g6pd5,6 background. Persulfidation occurs at Arabidopsis G6PD6 Cystine (Cys)159 and tomato G6PDC Cys155, leading to alterations of spatial distance between lysine (K)491-K475 from 42.0 Å to 10.3 Å within the G6PD tetramer. The structural alteration occurs in the structural NADP+ binding domain, which governs the stability of G6PD homooligomer. Persulfidation enhances G6PD oligomerization, thereby increasing substrate affinity. Under high salt stress, cytosolic G6PDs activity was inhibited due to oxidative modifications. Persulfidation protects these specific sites and prevents oxidative damage. In summary, H2 S-mediated persulfidation promotes cytosolic G6PD activity by altering homotetrameric structure. The cytosolic G6PD adaptive regulation with two kinds of protein modifications at the atomic and molecular levels is critical for the cellular stress response.

Distribution and characteristics of microplastics in sediment at representative dredged material ocean dumping sites, China.

Dredged material ocean dumping activities are likely an important source of microplastics (MPs) in coastal areas but have received little attention globally. In this study, we investigated the spatiotemporal distribution and characteristics of MPs in sediments at eight dredged material dumping sites of China. MPs were separated from sediment through density flotation, and polymer types were identified using µ-FTIR. The results showed that the average MP abundance was 112.82 ± 109.68 items/kg d.w. The MPs were more abundant at nearshore dumping sites than at distant dumping sites. Dumping activities may be the main contributor of MPs to Site BD1, the farthest dumping site from shore, but only a minor source of MPs at the other dumping sites. The characteristics of MPs were dominated by transparent PET fibers <1 mm. Overall, sediments at the dumping sites exhibited relatively low to moderate concentrations of MPs in comparison to most other coastal sediments.

Hydrogen sulfide improves salt tolerance through persulfidation of PMA1 in Arabidopsis.

KEY MESSAGE: A new interaction was found between PMA1 and GRF4. H2S promotes the interaction through persulfidated Cys446 of PMA1. H2S activates PMA1 to maintain K+/Na+ homeostasis through persulfidation under salt stress. Plasma membrane H+-ATPase (PMA) is a transmembrane transporter responsible for pumping protons, and its contribution to salt resistance is indispensable in plants. Hydrogen sulfide (H2S), a small signaling gas molecule, plays the important roles in facilitating adaptation of plants to salt stress. However, how H2S regulates PMA activity remains largely unclear. Here, we show a possible original mechanism for H2S to regulate PMA activity. PMA1, a predominant member in the PMA family of Arabidopsis, has a non-conservative persulfidated cysteine (Cys) residue (Cys446), which is exposed on the surface of PMA1 and located in cation transporter/ATPase domain. A new interaction of PMA1 and GENERAL REGULATORY FACTOR 4 (GRF4, belongs to the 14-3-3 protein family) was found by chemical crosslinking coupled with mass spectrometry (CXMS) in vivo. H2S-mediated persulfidation promoted the binding of PMA1 to GRF4. Further studies showed that H2S enhanced instantaneous H+ efflux and maintained K+/Na+ homeostasis under salt stress. In light of these findings, we suggest that H2S promotes the binding of PMA1 to GRF4 through persulfidation, and then activating PMA, thus improving the salt tolerance of Arabidopsis.

Nitric oxide induces S-nitrosylation of CESA1 and CESA9 and increases cellulose content in Arabidopsis hypocotyls.

Nitric oxide (NO), a small signaling gas molecule, participates in several growth and developmental processes in plants. However, how NO regulates cell wall biosynthesis remains unclear. Here, we demonstrate a positive effect of NO on cellulose content that may be related to S-nitrosylation of cellulose synthase 1 (CESA1) and CESA9. Two S-nitrosylated cysteine (Cys) residues, Cys562 and Cys641, which are exposed on the surface of CESA1 and CESA9 and located in the cellulose synthase catalytic domain, were identified to be S-nitrosylated. Meanwhile, Cys641 was located on the binding surface of CESA1 and CESA9, and Cys562 was very close to the binding surface. Cellulose synthase complexes (CSCs) dynamics are closely associated with cellulose content. S-nitrosylation of CESA1 and CESA9 improved particles mobility and thus increased the accumulation of cellulose in Arabidopsis hypocotyl cells. An increase in hemicellulose content as well as an alteration in pectin content facilitated cell wall extension and contributed to cell growth, finally promoting elongation of Arabidopsis hypocotyls. Overall, our work provides a path to investigate the way NO affects the cellulose content of plants.