Functional assignment to positively selected sites in the core type III effector RipG7 from Ralstonia solanacearum

The soil‐borne pathogen Ralstonia solanacearum causes bacterial wilt in a broad range of plants. The main virulence determinants of R. solanacearum are the type III secretion system (T3SS) and its associated type III effectors (T3Es), translocated into the host cells. Of the conserved T3Es among R. solanacearum strains, the Fbox protein RipG7 is required for R. solanacearum pathogenesis on Medicago truncatula. In this work, we describe the natural ripG7 variability existing in the R. solanacearum species complex. We show that eight representative ripG7 orthologues have different contributions to pathogenicity on M. truncatula: only ripG7 from Asian or African strains can complement the absence of ripG7 in GMI1000 (Asian reference strain). Nonetheless, RipG7 proteins from American and Indonesian strains can still interact with M. truncatula SKP1‐like/MSKa protein, essential for the function of RipG7 in virulence. This indicates that the absence of complementation is most likely a result of the variability in the leucine‐rich repeat (LRR) domain of RipG7. We identified 11 sites under positive selection in the LRR domains of RipG7. By studying the functional impact of these 11 sites, we show the contribution of five positively selected sites for the function of RipG7_CMR15 in M. truncatula colonization. This work reveals the genetic and functional variation of the essential core T3E RipG7 from R. solanacearum. This analysis is the first of its kind on an essential disease‐controlling T3E, and sheds light on the co‐evolutionary arms race between the bacterium and its hosts.     

Attention Deficit/Hyperactivity Disorder and Urinary Nonylphenol Levels: A Case-Control Study in Taiwanese Children

Objective

Nonylphenol (NP) belongs to the family of endocrine disruptors, and it is widely used in industrial applications and is ubiquitous in daily foods. Animal studies have suggested that NP exposure might promote motor hyperactivity, likely by causing deficits in dopaminergic neurons. However, research assessing NP exposure and epidemiology studies on human populations are limited. The aim of this study was to explore the association between child NP exposure and ADHD while considering particular covariants, such as lead levels and dopamine-related gene variations.

Methods

A case-control study was conducted on patients with clinically diagnosed ADHD; the Swanson, Nolan and Pelham, Fourth Revision (SNAP-IV) questionnaire was used to identify normal controls aged 4–15 years. Participants were examined for urinary NP concentrations, blood lead levels, and select single-nucleotide polymorphisms of two dopamine-related genes (D4 dopamine receptor, DRD4, and dopamine transporter, DAT1). Socio-demographic variables, maternal lifestyle factors during pregnancy and family medical history were obtained using a questionnaire.

Results

A total of 97 children with doctor-diagnosed ADHD and 110 normal controls were enrolled. The blood lead levels in both groups were similar (1.57±0.73 vs. 1.73±0.77 μg/dL, p = 0.15). No significant difference in urinary NP concentration was found between the children with ADHD and the control subjects (4.52±3.22 μg/g cr. vs. 4.64±2.95 μg/g cr., p = 0.43). ADHD was significantly more prevalent among males in this study (male to female ratio: 5:1 for the ADHD group and 1.3:1 for the control group, p<0.01). The analysis was repeated after excluding the females, but this had no effect on the association between NP and ADHD. The regression model, including or excluding females, indicated no increased odds of having ADHD in the context of NP exposure after adjusting for covariants.

Conclusion

This study indicated that NP exposure might not promote ADHD in children, even though children in Taiwan had relatively high levels of NP compared to those reported previously and those in developed nations.     

Secondary Solid Organ Neoplasm in Patients with Acute Lymphoblastic Leukemia: A Nationwide Population-Based Study in Taiwan

BackgroundAcute lymphoblastic leukemia (ALL) is more common in children than in adults. Secondary neoplasms (SNs) in childhood ALL have been widely reported. However, only one study has demonstrated SNs in adult ALL. Because of the poorer survival of adult ALL, the incidence might be underestimated.ObjectiveTo evaluate the incidence and risk factors of secondary solid organ neoplasms among adult and child ALL patients.MethodsNewly diagnosed ALL patients between 1997 and 2011 were recruited from the Taiwan National Health Insurance database. Those who had antecedent or combined malignancies were excluded. Standardized incidence ratios (SIRs) were analyzed to compare the risk of our cohort to general population in the same age, sex and calendar year. Risk factors for SN development were analyzed by Cox proportional hazards models. Effects of treatments were treated as time-dependent variables.ResultsThe 15-year cumulative incidence of SN was 1.9% and 8.4% in 1,381 child and 2,154 adult ALL patients, respectively. The SIR was significantly increased in child ALL (SIR 6.06), but not in adult ALL (SIR 1.16). The SIRs of follow-up periods were 5.14, 2.24, .87 and .71 at ≥ 10 years, 5–10 years, 1–5 years and 0–1, respectively. Overall, 15 SNs developed, and CNS tumors (SIR 11.56) were the most common type. Multivariate analysis showed that age ≥ 20 years (hazard ratio [HR] 5.04), end-stage renal disease (HR 18.98) and cranial irradiation (HR 8.12) were independent risk factors for cancer development.ConclusionsWhen compared with the general population, child ALL shows a increased risk of developing SNs. CNS tumors are the most common type, and cranial irradiation is an independent risk factor. With longer follow-up, the risk of SNs increases. Hence, physicians need to pay more attention on the risk of developing SNs in long-term ALL survivors with risk factors.     

Reorganization of a novel vimentin-associated protein in 3T3-L1 cells during adipose conversion

We have found that the antibody A2, a marker for the capsule of steroidogenic lipid droplets, reacts with an intermediate filament-associated protein, P₂₀₀, in 3T3-L1 preadipocytes. Supporting evidence came from the colocalization pattern of P₂₀₀ with vimentin in double label experiments. The association of P₂₀₀ with vimentin was further confirmed by its copurification with vimentin after high salt extraction and colocalization of these two proteins in high salt-extracted and vinblastine-treated cells. In preadipocytes this protein was distributed on the vimentin filament network. At the early stage of adipose conversion, this protein was found to encircle nascent lipid droplets ranging from 0.1 to 0.2 μm, accompanied with a decreased distribution on the vimentin filament system. This infers a possible translocation of P₂₀₀ from the vimentin filaments to the droplet surface. Meanwhile, the vimentin filaments remained in a normal distribution in the cytoplasm and were apparently not associated with the nascent droplet. The association of vimentin filaments to droplet surfaces became prominent in lipid droplets larger than 0.2 μm, forming a typical vimentin cage. Immunogold staining also confirmed the translocation of P₂₀₀ immunoreactivity from the droplet surface to the vimentin cage. The relocation of P₂₀₀ from the cytoplasmic vimentin filaments to the droplet surface prior to the formation of the vimentin cage, as well as the reorganization of this protein in the vimentin cage, suggests a stabilizing role in the lipid droplet formation and an inducing function of this protein in the formation of the vimentin cage. J. Cell. Biochem. 67:84–91, 1997. © 1997 Wiley-Liss, Inc.     

中国苔类新植物

植物体黄绿色,极纤细,常常疏松交织丛生或散生于白发藓——鞭苔群落中。茎长5毫米,直径51微米,匍匐生长,具不规则1-3次羽状分枝。茎横断面的表皮细胞8个,12.8-9.6微米,圆方形。     

A Study on the Pollen Morphology in Trochodendron,Tetracentron and Euptelea

Trochodendron, Tetracentron and Euptelea are considered as a small group of the primitive angiosperms. They are endemic to or mainly distributed in China. Their systematic position has long been debated. The purpose of the present work is to present palynological data both for systematic discussion and for the identification of fossil pollen. The three genera share a number of pollen characters, for example, being spheroid in shape, exine surface distinctly reticulate and lumina rather small and irregular in shape, etc. They are, however, obviously different in other respects of pollen morphology. The pollen grains of Euptelea are the largest of three (c. 30 μm in diameter), those of Tetracentron, the smallest (c. 15) and those of Trochodendron, intermediate (c. 20), 3-colpate in Trochodendron and Tetracentron, and those in Euptelea are 3-celpate but with transitional apertures in one species and 6-rugate, not 3-colpate, in the other. The ruga membranes are coarsely granular (rod-shaped elements under SEM). The lumina are the smallest in Euptelea. Muri in Tetracentron are distinctly striate. Thus, the establishment of three separate families is supported by pollen morphology. Since the pollen grains of Trochodendron and Tetracentron are 3-colpate and those of Magnoliaceae are 1-sulcate, it seems unreasonable to refer them to Magnoliaceae (or Magnoliales). If the rugae of pollen grains in Euptelea further shortened and their number increased, they would resemble those of Hamamelidaceae (such as Sycopsis). Pollen morphology, therefore, suggests that Euptelea is related to Hamamelidales, and supports Cronquist’s viewpoint. Hutchinson (1969) includes both Trochodendron and Euptelea in the same family (Trochodendraceae). However, these two genera are rather distinct in morphology and structure, the presence or absence of vessels and chromosome number, etc. Pollen morphology of two genera also disagrees with the Hutchinson’s viewpoint.     

中国西藏藓类植物四新种

植物体中等大小,黄绿色或暗绿色,茎高5-8厘米,具3-5分枝下部和中上部被稀疏假根。叶密生,宽披针形,基部宽,向上渐狭,潮湿时伸展,干燥时稍呈镰刀状弯曲;叶缘平展,上部具齿突,中肋较宽,长达时尖部或突出,上部背面具齿突,横切面主细胞排列不整齐,其背、腹两侧均有分化付细胞;叶片中下部细胞长形,不规则,壁强烈加厚,具明显壁孔,上部细胞不整齐,略呈多边形,背面买明显的疵,角细胞发达,黄褐色,通常由3-4层细胞组成。     

朝鲜北部的苔藓植物

朝鲜是同我国一江之隔的友好邻邦,它有着很多与我国东北地区共同的植物种类。因此,对朝鲜苔藓植物的研究,为进一步研究我国东北地区苔藓植物种属的起源、演化和分布区等具有重要的意义。笔者于1979年7月17日至8月29日,曾以中国科学院植物分类学赴朝考察组的组员身份,到朝鲜进行了苔藓植物学方面的考察并收集了有关资料。根据这些标本资科和有关文献,加以分析和研究后写成了本文。