Superconductivity and Charge-Density-Wave-Like Transition in Th2Cu4As5.

We report the synthesis, crystal structure, and physical properties of a novel ternary compound, Th2Cu4As5. The material crystallizes in a tetragonal structure with lattice parameters a = 4.0639(3) Å and c = 24.8221(17) Å. Its structure can be described as an alternating stacking of fluorite-type Th2As2 layers with antifluorite-type double-layered Cu4As3 slabs. The measurement of electrical resistivity, magnetic susceptibility, and specific heat reveals that Th2Cu4As5 undergoes bulk superconducting transition at 4.2 K. Additionally, all these physical quantities exhibit anomalies at 48 K, accompanied by a sign change in the Hall coefficient, suggesting a charge-density-wave-like (CDW) phase transition. Drawing from both experimental data and band calculations, we propose that the superconducting and CDW-like phase transitions are, respectively, associated with the Cu4As3 slabs and the As plane in the Th2As2 layers.

Tunable origami metastructure based on liquid crystal for curvature sensing.

In this paper, a liquid crystal (LC) tunable origami metastructure (OMS) designed for curvature sensing on cylindrical surfaces to measure their curvature is introduced. The LC employed is K15 (5CB) and the applicable band is 0.36∼23 GHz. When excited by electromagnetic waves (EMWs) within the 4∼16 GHz, the resonance frequency of the OMS shifts from 10.24 GHz to 10.144 GHz, corresponding to a change in absorption amplitude ranging from 0.773 to 0.920. In terms of curvature sensing, the detectable range of curvature spans from 0 to 0.327 mm-1. The maximum sensitivity (S) achieved for curvature measurement reaches 0.918/mm-1, accompanied by a quality factor (Q-factor) of 25.88. The proposed OMS embodies numerous excellent traits, including wide-range sensing capabilities and heightened S, promising for applications in bionic skin, smart robotics, and related fields.

The Role of CXCL11 and its Receptors in Cancer: Prospective but Challenging Clinical Targets.

Chemokine ligand 11 is a member of the CXC chemokine family and exerts its biological function mainly through binding to CXCR3 and CXCR7. The CXCL11 gene is ubiquitously overexpressed in various human malignant tumors; however, its specific mechanisms vary among different cancer types. Recent studies have found that CXCL11 is involved in the activation of multiple oncogenic signaling pathways and is closely related to tumorigenesis, progression, chemotherapy tolerance, immunotherapy efficacy, and poor prognosis. Depending on the specific expression of its receptor subtype, CXCL11 also has a complex 2-fold role in tumours; therefore, directly targeting the structure-function of CXCL11 and its receptors may be a challenging task. In this review, we summarize the biological functions of CXCL11 and its receptors and their roles in various types of malignant tumors and point out the directions for clinical applications.

CXCL11 is found in many types of cancer and affects how cancer cells grow and respond to treatments. This paper delves into the intricate dance between CXCL11 and its receptors in various types of cancer. Like a versatile actor playing different roles on stage, CXCL11 can either promote or hinder cancer growth depending on its interaction with specific receptors. Understanding how CXCL11 works could help develop new treatments for cancer, but it's a complex challenge because CXCL11 can have different effects depending on the type of cancer and which receptors it binds to.

Cast versus Kirschner wire fixation in type II paediatric phalangeal neck fractures.

PURPOSE: To compare the outcomes of type II pediatric phalangeal neck fractures (PPNFs) treated with closed reduction and cast immobilization (CRCI) versus closed reduction percutaneous pinning (CRPP), and evaluated the clinical efficacy of conservative versus surgical treatment of type II PPNFs via meta-analysis. METHODS: Patients aged ≤ 14 years with type II PPNFs were divided into conservative (CRCI) and operative (CRPP) groups. Radiographs measured angulation and translation; hand function was assessed with total active range of motion (TAM) and Quick-DASH. Complication rates were also compared between the groups. A meta-analysis of conservative versus operative treatment confirmed the clinical results. Statistical analysis was performed using SPSS 26.0 and R studio 3.0 with two-tailed, chi-squared, and Mann-Whitney U or t-tests, P < 0.05. Meta-analysis used fixed or random effects models, calculating mean differences and odds ratios for outcomes, and assessing heterogeneity with I2 and Q tests. RESULTS: Final angulation (3.4° ± 3.7° and 4.9° ± 5.4° vs. 3.6° ± 3.7° and 4.2° ± 4.3°) and displacement (6.3% ± 5.8% and 5.7% ± 4.7% vs. 5.8% ± 5.5% and 3.2% ± 4.2%) in the coronal and sagittal planes were not different statistically between the conservative and surgical groups (P > 0.05), but improved significantly compared to preoperative values (P < 0.05). Although Quick-DASH scores were comparable in both groups (P = 0.105), conservatively treated patients had a significantly better TAM at the last follow-up visit (P = 0.005). The complication rates were 24.2% and 41.7% in the surgical and conservatively treated groups respectively (P = 0.162). However, the latter primarily experienced imaging-related complications, whereas the former experienced functional complications (P = 0.046). Our meta-analysis (n = 181 patients) also showed comparable functional (P = 0.49) and radiographic (P = 0.59) outcomes and complication rates (P = 0.21) between the surgical (94 patients) and conservative (87 patients) groups. CONCLUSIONS: Conservative and surgical treatments are both reliable and safe approaches for managing type II PPNF in children. However, conservatively treated patients generally experience similar radiographic outcomes, lower complication rates, and better functional outcomes than surgically treated ones.

Oral appliance therapy vs. positional therapy for managing positional obstructive sleep apnea; a systematic review and meta-analysis of randomized control trials.

AIM: To assess the efficacy of positional therapy and oral appliance therapy for the management of positional obstructive sleep apnea. METHODS: We searched PubMed, Web of Science, Cochrane, and SCOPUS for relevant clinical trials. Quality assessment of the included trials was evaluated according to Cochrane's risk of bias tool. We included the following outcomes: The apnea-hypopnea index (AHI), AHI non-supine, AHI supine, sleep efficiency, percentage of supine sleep, Adherence (≥ 4 h/night, ≥ 5 days/week), Oxygen desaturation Index, Arousal Index, Epworth Sleepiness Scale score (ESS), Mean SpO2, and Functional Outcomes of Sleep Questionnaire. RESULTS: The AHI non-supine and the ESS scores were significantly lower in the OAT cohort than in the PT cohort. The PT cohort was associated with a significantly decreased percentage of supine sleep than the OAT cohort (MD= -26.07 [-33.15, -19.00], P = 0.0001). There was no significant variation between PT cohort and OAT cohort regarding total AHI, AHI supine, ODI, sleep efficiency, arousal index, FOSQ, adherence, and mean SpO2. CONCLUSION: Both Positional Therapy and Oral Appliance Therapy effectively addressed Obstructive Sleep Apnea. However, Oral Appliance Therapy exhibited higher efficiency, leading to increased supine sleep percentage and more significant reductions in the Apnea Hypopnea Index during non-supine positions, as well as lower scores on the Epworth Sleepiness Scale.

Using signal-to-cutoff ratios of HIV screening assay to predict HIV infection.

BACKGROUND: The sensitivity of HIV screening assays often leads to a high rate of false-positive results, requiring retests and confirmatory tests. This study aimed to analyze the capability of signal-to-cutoff (S/CO) ratios of HIV screening assay to predict HIV infection. METHODS: A retrospective study on the HIV screening-positive population was performed at Zhongshan Hospital, Xiamen University, the correlation between HIV screening assay S/CO ratios and HIV infection was assessed, and plotted Receiver Operating Characteristic (ROC) curves were generated to establish the optimal cutoff value for predicting HIV infection. RESULTS: Out of 396,679 patients, 836 were confirmed to be HIV-infected, with an HIV prevalence of 0.21%. The median S/CO ratios in HIV infection were significantly higher than that in non-HIV infection (296.9 vs. 2.41, P < 0.001). The rate of confirmed HIV infection was increased with higher S/CO ratios in the screening assay. The ROC curve based on the HIV screening assay S/CO ratio achieved a sensitivity of 93.78% and a specificity of 93.12% with an optimal cutoff value of 14.09. The area under the ROC curve was 0.9612. Further analysis of the ROC curve indicated that the S/CO ratio thresholds yielding positive predictive values of 99%, 99.5%, and 100% for HIV infection were 26.25, 285.7, and 354.5, respectively. CONCLUSION: Using HIV screening assay S/CO ratio to predict HIV infection can largely reduce necessitating retests and confirmatory tests. Incorporating the S/CO ratio into HIV testing algorithms can have significant implications for medical and public health practices.

Mallory-Weiss syndrome in four hemodialysis patients: a case study.

BACKGROUND: Hemodialysis patients are prone to gastrointestinal bleeding, and Mallory-Weiss syndrome (MWS) is one of the causes. Mallory-Weiss syndrome is often induced by severe vomiting, manifests as upper gastrointestinal bleeding, and is self-limited with a good prognosis. However, mild vomiting in hemodialysis patients can lead to the occurrence of MWS, and the mild early symptoms are easy to misdiagnose, leading to the aggravation of the disease. CASE PRESENTATION: In this paper, we report four hemodialysis patients with MWS. All patients displayed symptoms of upper gastrointestinal bleeding. The diagnosis of MWS was confirmed by gastroscopy. One patient had a history of severe vomiting; however, the other three reported histories of mild vomiting. Three patients received the conservative hemostasis treatment, and the gastrointestinal bleeding stopped. One patient underwent the gastroscopic and interventional hemostasis treatments. The conditions of three of the patients improved. Unfortunately, one of the patients died due to the cardia insufficiency. CONCLUSIONS: We think that the mild symptoms of MWS are easily covered up by other symptoms. This may lead to delays in diagnosis and treatment. For patients with severe symptoms, gastroscopic hemostasis is still the first choice, and interventional hemostasis can also be considered. For patients with mild symptoms, drug hemostasis is the first consideration.

Enhancement of sonodynamic treatment of ovarian cancer based on Pt-B-P ternary nanoparticles.

Sonodynamic therapy (SDT) can noninvasively focus sound energy to deep tumor tissues and activate sonosensitizer (such as chlorin e6(Ce6)) to produce antitumor effects. However, due to the hypoxic microenvironment of the tumor, the effect of sonodynamic therapy is limited. In this work, we successfully synthesized Platinum-Boron-Phosphorus ternary nanoparticles (Pt-B-P NPs) for the first time to efficiently catalyze the decomposition of hydrogen peroxide (H2O2) in tumor tissues to produce sufficient oxygen (O2) and improve the effect of sonodynamic treatment of ovarian cancer. In vitro studies, we found that compared with Platinum nanoparticles (Pt NPs), Pt-B-P NPs have the significantly increased ability to catalyze the decomposition of H2O2 to produce oxygen and thus the hypoxic environment of tumor cells could be improved efficiently. Meanwhile, the bio-distribution, therapeutic effect and bio-safety of Pt-B-P NPs in vivo were evaluated using BALB/c-nu mouse model of ovarian cancer and the desired result had been achieved.

The Effectiveness of Smartphone App-Based Interventions for Assisting Smoking Cessation: Systematic Review and Meta-analysis.

BACKGROUND: Smoking is a leading cause of premature death globally. Quitting smoking reduces the risk of all-cause mortality by 11%-34%. Smartphone app-based smoking cessation (SASC) interventions have been developed and are widely used. However, the evidence for the effectiveness of smartphone-based interventions for smoking cessation is currently equivocal. OBJECTIVE: The purpose of this study was to synthesize the evidence for the effectiveness of smartphone app-based interventions for smoking cessation. METHODS: We conducted a systematic review and meta-analysis of the effectiveness of smartphone interventions for smoking cessation based on the Cochrane methodology. An electronic literature search was performed using the Cochrane Library, Web of Science, PubMed, Embase, PsycINFO, China National Knowledge Infrastructure, and Wanfang databases to identify published papers in English or Chinese (there was no time limit regarding the publication date). The outcome was the smoking abstinence rate, which was either a 7-day point prevalence abstinence rate or a continuous abstinence rate. RESULTS: A total of 9 randomized controlled trials involving 12,967 adults were selected for the final analysis. The selected studies from 6 countries (the United States, Spain, France, Switzerland, Canada, and Japan) were included in the meta-analysis between 2018 and 2022. Pooled effect sizes (across all follow-up time points) revealed no difference between the smartphone app group and the comparators (standard care, SMS text messaging intervention, web-based intervention, smoking cessation counseling, or apps as placebos without real function; odds ratio [OR] 1.25, 95% CI 0.99-1.56, P=.06, I2=73.6%). Based on the subanalyses, 6 trials comparing smartphone app interventions to comparator interventions reported no significant differences in effectiveness (OR 1.03, 95% CI 0.85-1.26, P=.74, I2=57.1%). However, the 3 trials that evaluated the combination of smartphone interventions combined with pharmacotherapy compared to pharmacotherapy alone found higher smoking abstinence rates in the combined intervention (OR 1.79, 95% CI 1.38-2.33, P=.74, I2=7.4%). All SASC interventions with higher levels of adherence were significantly more effective (OR 1.48, 95% CI 1.20-1.84, P<.001, I2=24.5%). CONCLUSIONS: This systematic review and meta-analysis did not support the effectiveness of delivering smartphone-based interventions alone to achieve higher smoking abstinence rates. However, the efficacy of smartphone-based interventions increased when combined with pharmacotherapy-based smoking cessation approaches. TRIAL REGISTRATION: PROSPERO CRD42021267615; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=267615.

Depression, anxiety and stress among metastatic breast cancer patients on chemotherapy in China.

OBJECTIVE: This study aimed to assess the level of depression, anxiety and stress among metastatic breast cancer (MBC) patients undergoing chemotherapy (CT) in Beijing, China. METHODS: A cross-sectional study was conducted on 176 MBC women receiving CT, selected by purposive sampling. Data were collected using self-administered questionnaires that included participants' socio-demographic status, DASS-21 and Brief COPE. Data were analyzed using descriptive statistics and general linear regression analysis. RESULTS: The incidence of depression, anxiety and stress among MBC women were 52.3%, 60.2% and 36.9%, respectively. General linear regression showed that age, marital status, monthly income, physical functioning, emotional functioning, pain, dyspnea, and appetite loss were associated with depression. All variance determined the depression (R2) was 35.6%. Marital status, self-blame and behavioral disengagement were the predictors of stress and accounted for a 35.4% stress variance in MBC women. CONCLUSION: Our study demonstrated depression, anxiety, and stress prevalence are high in MBC women. Assessment of psychological distress (depression, anxiety, and stress) is important to recognise MBC patients who need help and further medical and mental help support. This study's findings can increasingly highlight that depression, anxiety, and stress are substantial problems in MBC patients. Therefore, psychological interventions are needed to reduce depression, anxiety, and stress for MBC patients.

Methods to detect and characterize introgression.

Introgression, also known as introgressive hybridization, refers to the process that genetic components from the gene pool of one population transfer to the other via constant backcrossing. Introgression is widespread in nature, which plays important roles in increasing genetic diversity and improving adaptability to the environment, and in turn, influences the evolutionary progress of animals, plants and humans. Being as an important evolutionary event, researchers pay great attention to the detection of introgression, the introgression direction, the introgression timing, the pattern of introgression and so on. With the rapid development of high-throughput sequencing technologies, methods to detect and characterize introgression based on genome-wide data are continuously developed. In this review, we summarize a series of methods for introgression detection, and introduce the design principles and applications of these methods. We also discuss the maintenance and selection of gene segments after introgression. This review provides a relatively comprehensive reference for the studies on introgression.

Metabolomic and regular analysis reveal phytotoxic mechanisms of sterigmatocystin in Amaranthus retroflexus L.

Sterigmatocystin (STE) is a common hepatotoxic and nephrotoxic contaminant in cereals, however, its phytotoxicity and mechanisms are poorly understood. Here, the phytotoxic mechanisms of STE were investigated via the metabolomics of Amaranthus retroflexus L. A total of 140 and 113 differential metabolites were detected in the leaves and stems, respectively, among which amino acids, lipids, and phenolic compounds were significantly perturbed. Valine, leucine, isoleucine, and lysine biosynthesis were affected by STE. These metabolic responses revealed that STE might be toxic to plants by altering the plasma membrane and inducing oxidative damage, which was verified by measuring the relative electrical conductivity and quantification of reactive oxygen species. The elevated amino acids, as well as the decreased of D-sedoheptuiose-7-phosphate indicated increased proteolysis and carbohydrate metabolism restriction. Furthermore, the IAA level also decreased. This study provides a better understanding of the impacts of STE on the public health, environment and food security.

Bacterial community in saline farmland soil on the Tibetan plateau: responding to salinization while resisting extreme environments.

BACKGROUND: Salinization damages the health of soil systems and reduces crop yields. Responses of microbial communities to salinized soils and their functional maintenance under high salt stress are valuable scientific problems. Meanwhile, the microbial community of the salinized soil in the plateau environment is less understood. Here, we applied metagenomics technology to reveal the structure and function of microorganisms in salinized soil of the Tibetan Plateau. RESULTS: The diversity of composition and function of microbial community in saline soil have changed significantly. The abundances of chemoautotrophic and acidophilic bacteria comprising Rhodanobacter, Acidobacterium, Candidatus Nitrosotalea, and Candidatus Koribacter were significantly higher in saline soil. The potential degradation of organic carbon in the saline soil, as well as the production of NO and N2O via denitrification, and the production of sulfate by sulfur oxidation were significantly higher than the non-saline soil. Both types of soils were rich in genes encoding resistance to environmental stresses (i.e., cold, ultraviolet light, and hypoxia in Tibetan Plateau). The resistance of the soil microbial communities to the saline environment is based on the absorption of K+ as the main mechanism, with cross-protection proteins and absorption buffer molecules as auxiliary mechanisms in our study area. Network analysis showed that functional group comprising chemoautotrophic and acidophilic bacteria had significant positive correlations with electrical conductivity and total sulfur, and significant negative correlations with the total organic carbon, pH, and available nitrogen. The soil moisture, pH, and electrical conductivity are likely to affect the bacterial carbon, nitrogen, and sulfur cycles. CONCLUSIONS: These results indicate that the specific environment of the Tibetan Plateau and salinization jointly shape the structure and function of the soil bacterial community, and that the bacterial communities respond to complex and harsh living conditions. In addition, environmental feedback probably exacerbates greenhouse gas emissions and accelerates the reduction in the soil pH. This study will provide insights into the microbial responses to soil salinization and the potential ecological risks in the special plateau environment.

LINC00958 promotes bladder cancer carcinogenesis by targeting miR-490-3p and AURKA.

BACKGROUND: Bladder cancer is a prevalent malignancy of the urinary system, in which long non-coding RNAs (lncRNAs) are highly associated. We aimed to elucidate the role of LINC00958 in bladder cancer. METHODS: LINC00958 expression levels were measured using qRT-PCR. The interaction of LINC00958-miR-490-3p-AURKA was analyzed by luciferase, RIP, and RNA pull-down assays. The biological roles of LINC00958, miR-490-3p, and AURKA in bladder cancer cells were analyzed using CCK8, BrdU, and transwell assays. RESULTS: Increased expression of LINC00958 and AURKA was observed in bladder cancer tissues and cell lines. Decreased LINC00958 expression repressed bladder cancer progression and downregulation of miR-490-3p accelerated bladder cancer cell progression. Moreover, LINC00958 sponges miR-490-3p to upregulate AURKA expression, thereby promoting carcinogenesis in bladder cancer cells. CONCLUSIONS: Our study revealed that LINC00958 facilitated cell proliferation and invasion, and suppressed cell apoptosis by sponging miR-490-3p and upregulating AURKA, thus inspiring a new treatment method for bladder cancer.

T cells participate in bone remodeling during the rapid palatal expansion.

Palatal expansion has been widely used for the treatment of transverse discrepancy or maxillae hypoplasia, but the biological mechanism of bone formation during this procedure is largely unknown. Osteoclasts, which could be regulated by T cells and other components of the immune system, play a crucial role in force-induced bone remodeling. However, whether T cells participate in the palatal expansion process remains to be determined. In this study, we conducted the tooth borne rapid palatal expansion model on the mouse, and detect whether the helper T cells (Th) and regulatory T cells (Treg) could affect osteoclasts and further bone formation. After bonding open spring palatal expanders for 3-day, 5-day, 7-day, and retention for 28-day, micro-computed tomography scanning, histologic, and immunofluorescence staining were conducted to evaluate how osteoclasts were regulated by T cells during the bone remodeling process. We revealed that the increased osteoclast number was downregulated at the end of the early stage of rapid palatal expansion. Type 1 helper T (Th1) cells and Type 17 helper T (Th17) cells increased initially and promoted osteoclastogenesis. Thereafter, the regulatory T (Treg) cells emerged and maintained a relatively high level at the late stage of the experiment to downregulate the osteoclast number by inhibiting Th1 and Th17 cells, which governed the new bone formation. In conclusion, orchestrated T cells are able to regulate osteoclasts at the early stage of rapid palatal expansion and further facilitate bone formation during retention. This study identifies that T cells participate in the palatal expansion procedure by regulating osteoclasts and implies the potential possibility for clinically modulating T cells to improve the palatal expansion efficacy.

Horseshoe kidney with PLA2R-positive membranous nephropathy.

BACKGROUND: Horseshoe kidney (HSK) is a common congenital defect of the urinary system. The most common complications are urinary tract infection, urinary stones, and hydronephrosis. HSK can be combined with glomerular diseases, but the diagnosis rate of renal biopsy is low due to structural abnormalities. There are only a few reports on HSK with glomerular disease. Here, we have reported a case of PLA2R-positive membranous nephropathy occurring in a patient with HSK. CASE PRESENTATION: After admission to the hospital due to oedema of both the lower extremities, the patient was diagnosed with nephrotic syndrome due to abnormal 24-h urine protein (7540 mg) and blood albumin (25 g/L) levels. Abdominal ultrasonography revealed HSK. The patient's brother had a history of end-stage renal disease due to nephrotic syndrome. Therefore, the patient was diagnosed with PLA2R-positive stage II membranous nephropathy through renal biopsy under abdominal ultrasonography guidance. He was administered adequate prednisone and cyclophosphamide, and after 6 months of treatment, urinary protein excretion levels significantly decreased. CONCLUSION: The risk and difficulty of renal biopsy in patients with HSK are increased due to structural abnormalities; however, renal biopsy can be accomplished through precise positioning with abdominal ultrasonography. In the literature, 20 cases of HSK with glomerular disease have been reported thus far. Because of the small number of cases, estimating the incidence rate of glomerular diseases in HSK is impossible, and the correlation between HSK and renal pathology cannot be stated. Further studies should be conducted and cases should be accumulated to elucidate this phenomenon.

LOX-1 (Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1) Deletion Has Protective Effects on Stroke in the Genetic Background of Stroke-Prone Spontaneously Hypertensive Rat.

Background and Purpose- oxLDL (oxidized low-density lipoprotein) has been known for its potential to induce endothelial dysfunction and used as a major serological marker of oxidative stress. Recently, LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1), a lectin-like receptor for oxLDL, has attracted attention in studies of neuronal apoptosis and stroke. We aim to investigate the impact of LOX-1-deficiency on spontaneous hypertension-related brain damage in the present study. Methods- We generated a LOX-1 deficient strain on the genetic background of stroke-prone spontaneously hypertensive rat (SHRSP), an animal model of severe hypertension and spontaneous stroke. In this new disease model with stroke-proneness, we monitored the occurrence of brain abnormalities with and without salt loading by multiple procedures including T2 weighted magnetic resonance imaging and also explored circulatory miRNAs as diagnostic biomarkers for cerebral ischemic injury by microarray analysis. Results- Both T2 weighted magnetic resonance imaging abnormalities and physiological parameter changes could be detected at significantly delayed timing in LOX-1 knockout rats compared with wild-type SHRSP, in either case of normal rat chow and salt loading (P<0.005 in all instances; n=11-20 for SHRSP and n=13-23 for LOX-1 knockout rats). There were no significant differences in the form of magnetic resonance imaging findings between the strains. A number of miRNAs expressed in the normal rat plasma, including rno-miR-150-5p and rno-miR-320-3p, showed significant changes after spontaneous brain damage in SHRSP, whereas the corresponding changes were modest or almost unnoticeable in LOX-1 knockout rats. There appeared to be the lessening of correlation of postischemic miRNA alterations between the injured brain tissue and plasma in LOX-1 knockout rats. Conclusions- Our data show that deficiency of LOX-1 has a protective effect on spontaneous brain damage in a newly generated LOX-1-deficient strain of SHRSP. Further, our analysis of miRNAs as biomarkers for ischemic brain damage supports a potential involvement of LOX-1 in blood brain barrier disruption after cerebral ischemia. Visual Overview- An online visual overview is available for this article.

Identification of quantitative trait loci for kernel-related traits and the heterosis for these traits in maize (Zea mays L.).

Heterosis has been extensively applied for many traits during maize breeding, but there has been relatively little attention paid to the heterosis for kernel size. In this study, we evaluated a population of 301 recombinant inbred lines derived from a cross between 08-641 and YE478, as well as 298 hybrids from an immortalized F2 (IF2) population to detect quantitative trait loci (QTLs) for six kernel-related traits and the mid-parent heterosis (MPH) for these traits. A total of 100 QTLs, six pairs of loci with epistatic interactions, and five significant QTL × environment interactions were identified in both mapping populations. Seven QTLs accounted for over 10% of the phenotypic variation. Only four QTLs affected both the trait means and the MPH, suggesting the genetic mechanisms for kernel-related traits and the heterosis for kernel size are not completely independent. Moreover, more than half of the QTLs for each trait in the IF2 population exhibited dominance, implying that dominance is more important than other genetic effects for the heterosis for kernel-related traits. Additionally, 20 QTL clusters comprising 46 QTLs were detected across ten chromosomes. Specific chromosomal regions (bins 2.03, 6.04-6.05, and 9.01-9.02) exhibited pleiotropy and congruency across diverse heterotic patterns in previous studies. These results may provide additional insights into the genetic basis for the MPH for kernel-related traits.

Genetic dissection of yield-related traits and mid-parent heterosis for those traits in maize (Zea mays L.).

BACKGROUND: Utilization of heterosis in maize could be critical in maize breeding for boosting grain yield. However, the genetic architecture of heterosis is not fully understood. To dissect the genetic basis of yield-related traits and heterosis in maize, 301 recombinant inbred lines derived from 08 to 641 × YE478 and 298 hybrids from the immortalized F2 (IF2) population were used to map quantitative trait loci (QTLs) for nine yield-related traits and mid-parent heterosis. RESULTS: We observed 156 QTLs, 28 pairs of loci with epistatic interaction, and 10 significant QTL × environment interactions in the inbred and hybrid mapping populations. The high heterosis in F1 and IF2 populations for kernel weight per ear (KWPE), ear weight per ear (EWPE), and kernel number per row (KNPR) matched the high percentages of QTLs (over 50%) for those traits exhibiting overdominance, whereas a notable predominance of loci with dominance effects (more than 70%) was observed for traits that show low heterosis such as cob weight per ear (CWPE), rate of kernel production (RKP), ear length (EL), ear diameter (ED), cob diameter, and row number (RN). The environmentally stable QTL qRKP3-2 was identified across two mapping populations, while qKWPE9, affecting the trait mean and the mid-parent heterosis (MPH) level, explained over 18% of phenotypic variations. Nine QTLs, qEWPE9-1, qEWPE10-1, qCWPE6, qEL8, qED2-2, qRN10-1, qKWPE9, qKWPE10-1, and qRKP4-3, accounted for over 10% of phenotypic variation. In addition, QTL mapping identified 95 QTLs that were gathered together and integrated into 33 QTL clusters on 10 chromosomes. CONCLUSIONS: The results revealed that (1) the inheritance of yield-related traits and MPH in the heterotic pattern improved Reid (PA) × Tem-tropic I (PB) is trait-dependent; (2) a large proportion of loci showed dominance effects, whereas overdominance also contributed to MPH for KNPR, EWPE, and KWPE; (3) marker-assisted selection for markers at genomic regions 1.09-1.11, 2.04, 3.08-3.09, and 10.04-10.05 contributed to hybrid performance per se and heterosis and were repeatedly reported in previous studies using different heterotic patterns is recommended.

Maize brachytic2 (br2) suppresses the elongation of lower internodes for excessive auxin accumulation in the intercalary meristem region.

BACKGROUND: Short internodes contribute to plant dwarfism, which is exceedingly beneficial for crop production. However, the underlying mechanisms of internode elongation are complicated and have been not fully understood. RESULTS: Here, we report a maize dwarf mutant, dwarf2014 (d2014), which displays shortened lower internodes. Map-based cloning revealed that the d2014 gene is a novel br2 allele with a splicing variation, resulting in a higher expression of BR2-T02 instead of normal BR2-T01. Then, we found that the internode elongation in d2014/br2 exhibited a pattern of inhibition-normality-inhibition (transient for the ear-internode), correspondingly, at the 6-leaf, 12-leaf and 14-leaf stages. Indeed, BR2 encodes a P-glycoprotein1 (PGP1) protein that functions in auxin efflux, and our in situ hybridization assay showed that BR2 was mainly expressed in vascular bundles of the node and internode. Furthermore, significantly higher auxin concentration was detected in the stem apex of d2014 at the 6-leaf stage and strictly in the node region for the ear-internode at the 14-leaf stage. In such context, we propose that BR2/PGP1 transports auxin from node to internode through the vascular bundles, and excessive auxin accumulation in the node (immediately next to the intercalary meristem) region suppresses internode elongation of d2014. CONCLUSIONS: These findings suggest that low auxin levels mediated by BR2/PGP1 in the intercalary meristem region are crucial for internode elongation.