Heterozygous CAPZA2 mutations cause global developmental delay, hypotonia with epilepsy: a case report and the literature review.

CAPZA2 encodes the α2 subunit of CAPZA, which is vital for actin polymerization and depolymerization in humans. However, understanding of diseases associated with CAPZA2 remains limited. To date, only three cases have been documented with neurodevelopmental abnormalities such as delayed motor development, speech delay, intellectual disability, hypotonia, and a history of seizures. In this study, we document a patient who exhibited seizures, mild intellectual disability, and impaired motor development yet did not demonstrate speech delay or hypotonia. The patient also suffered from recurrent instances of respiratory infections, gastrointestinal and allergic diseases. A novel de novo splicing variant c.219+1 G > A was detected in the CAPZA2 gene through whole-exome sequencing. This variant led to exon 4 skipping in mRNA splicing, confirmed by RT-PCR and Sanger sequencing. To our knowledge, this is the third study on human CAPZA2 defects, documenting the fourth unambiguously diagnosed case. Furthermore, this splicing mutation type is reported here for the first time. Our research offers additional support for the existence of a CAPZA2-related non-syndromic neurodevelopmental disorder. Our findings augment our understanding of the phenotypic range associated with CAPZA2 deficiency and enrich the knowledge of the mutational spectrum of the CAPZA2 gene.

Tobacco Root Microbial Community Composition Significantly Associated With Root-Knot Nematode Infections: Dynamic Changes in Microbiota and Growth Stage.

The root-knot nematode (RKN) is an important pathogen that affects the growth of many crops. Exploring the interaction of biocontrol bacteria-pathogens-host root microbes is the theoretical basis for improving colonization and controlling the effect of biocontrol bacteria in the rhizosphere. Therefore, 16S and 18S rRNA sequencing technology was used to explore the microbial composition and diversity of tobacco roots (rhizosphere and endophytic) at different growth stages in typical tobacco RKN-infected areas for 2 consecutive years. We observed that RKN infection changed the α-diversity and microbial composition of root microorganisms and drove the transformation of microorganisms from bacteria to fungi. The abundance of Sphingomonas decreased significantly from 18% to less than 3%, while the abundance of Rhizobiaceae increased from 4 to 15% at the early growth stage during the first planting year, and it promoted the proliferation of Chryseobacterium at the late growth stage in rhizosphere microorganisms with the highest abundance of 17%. The overall trend of rhizosphere microorganisms changed in the early growth stage with increasing growth time. The specific results were as follows: (1) Rhizobiaceae and Chryseobacterium increased rapidly after 75 days, became the main abundant bacteria in the rhizosphere microorganisms. (2) The dominant flora in fungi were Fusarium and Setophoma. (3) Comparing the root microbes in 2017 and 2018, RKN infection significantly promoted the proliferation of Pseudomonas and Setophoma in both the rhizosphere and endophytes during the second year of continuous tobacco planting, increasing the relative abundance of Pseudomonas from 2 to 25%. Pseudomonas was determined to play an important role in plant pest control. Finally, a total of 32 strains of growth-promoting bacteria were screened from tobacco rhizosphere bacteria infected with RKN through a combination of 16S rRNA sequencing and life-promoting tests. The results of this research are helpful for analyzing the relationship between RKNs and bacteria in plants, providing reference data for elucidating the pathogenesis of RKNs and new ideas for the biological control of RKNs. GRAPHICAL ABSTRACT.

Potassium accumulation characteristics and expression of related genes involved in potassium metabolism in a high-potassium variety: tobacco (Nicotiana tabacum) as a model.

We investigated potassium (K) accumulation characteristics and expression of K metabolism related genes in one high-K variety (ND202) and a common variety (NC89) of tobacco (Nicotiana tabacum L.). Results showed that K accumulation and leaf K content in ND202 were higher than those in NC89. The distribution rate and K accumulation in the leaves of ND202 increased significantly, while the distribution rate in the roots and stems had lower values. In addition, the maximum K accumulation rate and high-speed K accumulation duration in ND202 were found to be better than those in NC89. The expression of NKT1 in the upper and middle leaves of ND202 had an advantage, and the relative expression of NtKC1 and NtTPK1 in both the upper and middle leaves, as well as the roots, was also significantly upregulated. Conversely, the expression of NTRK1 in the lower leaves and roots of ND202 was weaker. ND202 had significantly greater expression levels of NtHAK1 than NC89 in the upper and middle leaves and roots; moreover, the expression of NtKT12 in the upper leaves and roots of ND202 was also higher. In comparison with common varieties, high-K varieties had a stronger ability to absorb and accumulate K. They also possessed higher expression of K+ channel- and transporter-related genes and showed a superior K accumulation rate and longer duration of high-speed K accumulation. Furthermore, K accumulation rate at 40-60days can be suggested as an important reference for the selection of high-K tobacco varieties.

[Clinical characteristics and follow-up management of 135 children with myasthenia gravis].

OBJECTIVE: To investigate and analyze the clinical manifestations, classification, therapeutic approaches and follow-up of myasthenia gravis (MG) in children in order to improve its management and prognosis. METHODS: Clinical information of 135 children with MG, who were diagnosed between January 1993 to January 2008, were collected and retrospectively analyzed. And prospective following-up of these patients were conducted. RESULTS: Among the 135 cases, 59 were males and 76 females, giving the ratio of M/F around 1:1.3. Totally, 115 cases (85.2%) were type I MG (ocular type), of which only 4.2% developed to generalized type during the subsequent clinical course. Type II MG (generalized type)was found in 18 cases (13.4%) and type III MG in two cases(1.5%). The onset age ranged from 5 month to 15 years, with 50.3% before three years and 80.7% before seven years. Upper respiratory tract infection was presented in 26.7% (36/135) of the sick children before the onset of MG. Among the 106 children being followed up, recurrence of the disease identified in 50.9% and the number of relapse ranged from 1 to 9. Altogether, 40.19% (43/106) of the cases were positive for anti-acetylcholine receptor antibodies (AchR-Ab) on the initial examination, and the AchR-Ab postitive rate showed no difference among different clinical subtypes and states. However, during the follow-up, 53% (9/17) of the recurrent cases, who were negative at the first onset, turned to be positive, and 37.97% (30/79) were positive for repetitive nerve stimulation in electromyogram test. There were 71 % (45/63) of all the cases showed reduced levels of CD4+ and/or CD3+ and/or CD8+. Thymus proliferation was found in 5.93% (8/135) through CT scan and thymoma in 1.48% (2/135). Steroids and anti-cholinesterase administration were effective in most cases with good prognosis. CONCLUSION: Childhood MG, mainly type I, is relatively common in China, with specific characteristics which are different from western patients or adult MG in morbidity, sex distribution, progress, laboratory examination and treatment. The prevalence of myasthenia gravis crisis and mortality rate in MG children is low, and few are accompanied with thymoma. Most MG cases have a satisfied prognosis and few have neuropsychic sequela.

Activation of potassium released from soil by root-secreted organic acids in different varieties of tobacco (Nicotiana tabacum).

Organic acids secreted from the roots of plants play important roles in nutrient acquisition and metal detoxification; however, the precise underlying mechanisms of these processes remain poorly understood. In the present study we examined the content of organic acids exuded from roots and the effects of these organic acids on the activation of slowly available potassium (K) at different K levels, including normal K supply and K-deficient conditions. In addition, the study system also comprised a high-K tobacco variety (ND202) and two common ones (K326 and NC89). Our results showed that high-K varieties exhibited significantly higher contents of organic acids in its root exudates and available K in both rhizosphere and non-rhizosphere soils than the other varieties. This research also suggested that a cyclic process in which soil was acidified after being complexed by organic acids was involved in the release of slowly available K, and that this process primarily depended on the soil pH at high organic acids concentrations, but the complexation of organic ligands became dominant at low concentrations. In conclusion, tobacco roots secrete organic acids to increase available K content and improve the utilisation rate of soil K. High-K varieties probably enhance slowly available K activation by secreting relatively high amounts of organic acids, thus leading to more available K in soil for absorption by plants.

Clinical characteristics and therapeutic evaluation of childhood myasthenia gravis.

This study aimed to analyze the clinical characteristics, classification and treatment of childhood myasthenia gravis (MG) and address the prognosis through follow-up. The clinical data of 135 children with MG were grouped according to clinical type and therapeutic drugs, retrospectively analyzed and prospectively monitored. Of the 135 MG patients, 85.2% had type I (ocular type), with only 4.2% progressing to systemic MG; 13.4% had type II (general type); and 1.5% had type III (fulminating type). Relapse occurred in 46.1% of the 102 patients that were followed up. The positive rate for the primary acetylcholine receptor antibody was 40.19%, without significant differences among clinical subtypes. The positive rate of the repetitive nerve stimulation frequency test by electromyography was 37.97%. Decreased expression of CD4+, CD8+, or CD3+ was present in 71% of the patients. Thymic hyperplasia was present in 5.93% of the patients, while 1.48% had thymoma. Steroid treatment was effective in the majority of the patients. Ocular type MG was common in this cohort of patients. The incidence and mortality of myasthenia crisis were low, the presence of concurrent thymoma was rare and only a limited number of children developed neurological sequelae.

[Nitrogen uptake and allocation characteristics of flue-cured tobacco in Nanxiong tobacco-planting area of Guangdong Province].

By the method of field in situ culture and 15N isotopic tracer technique, and taking flue-cured tobacco (Nicotiana tobacum) cultivar K326 as test material, a field experiment was conducted in the Nanxiong tobacco-planting area of Guangdong Province to study the characteristics of soil nitrogen (N) mineralization, the patterns of N accumulation and allocation in tobacco plants, and the allocation of plant-absorbed fertilizer N applied in current growth season. In the study area, the amount of soil mineralized N increased with tobacco growth, peaked at 75 days after transplanting, and decreased thereafter. The soil mineralized N at each tobacco growth stage was significantly higher in the control than in the N fertilization treatment. The N accumulation in tobacco plant organs was in the order of leaf > stalk > root. Tobacco plants mainly absorbed fertilizer N at rosette stage and topping stage, and mainly absorbed soil N at mature stage. The absorbed N in tobacco whole growth period was mainly derived from soil N, and the absorbed soil N and its proportion to the total absorbed N increased evidently with extending growth stage and ascending leaf position. The fertilizer N use efficiency per plant and the residual rate and loss rate of applied fertilizer N were 30. 8%, 32. 3% , and 36. 9% , respectively. In the study area, soil N mineralization rate was relatively high, and soil N had greater effects on the quality of upper tobacco leaves. Under the application rate of 150 kg N x hm(-2), the residual amount and loss amount of applied fertilizer N were relatively high.

[Effects of nitrogen fertilization on leaf senescence, photosynthetic characteristics, yield, and quality of different flue-cured tobacco varieties].

Taking three flue-cured tobacco (Nicotiana tabacum L.) varieties Y5, Y7, and NC89 as test objects, this paper studied the effects of nitrogen fertilization on their leaf senescence, photosynthetic characteristics, yield, and quality. Increasing nitrogen supply increased the leaf superoxide dismutase (SOD) activity, chlorophyll content, and photosynthetic performance, and decreased the leaf malondialdehyde (MDA) content significantly. Accordingly, the leaf senescence was delayed. Compared with Y5 and NC89, variety Y7 had higher leaf MDA content and lower leaf SOD activity, chlorophyll content, and photosynthetic performance, and thus, its leaves senesced faster. High quality tobacco leaves with higher average price, gross value, superior leaves percentage, and reasonable chemical constituents were harvested under the application of 45 kg N x hm(-2), compared with applying 60 and 75 kg N x hm(-2). It was suggested that different flue-cured tobacco varieties had obvious differences in their leaf senescence physiological characteristics, and nitrogen fertilization played important roles in regulating their leaf senescence, yield, and quality. Appropriate nitrogen fertilization could improve the quality of tobacco leaves, and achieve higher economic benefits.

[Effects of different planting patterns on the senescence characteristics of flue-cured tobacco roots and leaves].

With flue-cured tobacco (Nicotiana tabacum) cultivar K326 as test material, a field experiment was conducted at Nanxiong area of Guangdong Province in 2008 to study the effects of four planting patterns, i.e., single-row ridge + film mulching at early stage, single-row ridge + film mulching at early and late stages, double-row concave ridge + film mulching at early stage, and double-row concave ridge + film mulching at early and late stages, on the senescence characteristics of its roots and leaves, and the economic traits of its leaves. Comparing with other three planting patterns, double-row concave ridge + film Aulching at early and late stages promoted the root growth of test cultivar during its whole growth period, with the root vigor increased significantly. Meanwhile, the leaf chlorophyll content and protective enzymes (SOD and POD) activities were higher, and the MDA content was lower. The leaf yield, output value, average price, and the proportion of superior leaves were also higher. Double-row concave ridge + film mulching at early and late stages alleviated the senescence characteristics of roots and leaves, and improved the economic traits of flue-cured tobacco leaves, being the efficient planting pattern to product high-quality flue-cured tobacco leaves in Nanxiong tobacco-growing area of Guangdong Province.