DNA methylation is an epigenetic modification required for transposable element (TE) silencing, genome stability, and genomic imprinting. Although DNA methylation has been intensively studied, the ...dynamic nature of methylation among different species has just begun to be understood. Here we summarize the recent progress in research on the wide variation of DNA methylation in different plants, organs, tissues, and cells; dynamic changes of methylation are also reported during plant growth and development as well as changes in response to environmental stresses. Overall DNA methylation is quite diverse among species, and it occurs in CG, CHG, and CHH (H = A, C, or T) contexts of genes and TEs in angiosperms. Moderately expressed genes are most likely methylated in gene bodies. Methylation levels decrease significantly just upstream of the transcription start site and around transcription termination sites; its levels in the promoter are inversely correlated with the expression of some genes in plants. Methylation can be altered by different environmental stimuli such as pathogens and abiotic stresses. It is likely that methylation existed in the common eukaryotic ancestor before fungi, plants and animals diverged during evolution. In summary, DNA methylation patterns in angiosperms are complex, dynamic, and an integral part of genome diversity after millions of years of evolution.
The effect of the output impedance of peaking power amplifier (PA) on Doherty PAs (DPAs) is analyzed in this paper. In the design procedure of DPAs, the ideal case is that the output impedance of ...auxiliary PA is infinite at output power back-off (OPBO) level. However, it is almost impossible to realize this perfect condition in broadband DPAs. Therefore, when the output impedance of peaking path deviates from infinity, some potential effects on DPAs must be produced. In this paper, these effects are explained at the internal plane of transistors. The conclusion is that, at different normalized frequencies, there are different optimal impedance regions for the output impedance of peaking stage. This means that the noninfinite output impedances of peaking stage can enhance the performances of broadband DPAs so long as they are elaborately processed. A 1.65-2.7-GHz (48% bandwidth) broadband DPA is designed considering the effects of peaking PA. The experimental results show that this DPA obtains a drain efficiency of 41%-59.6% at 6-dB OPBO levels and a drain efficiency of 55.8%-72.2% at saturation power levels. The maximum output power across the entire operating band is 43.1-45.2 dBm with a gain of 9.0-10.2 dB. Furthermore, the designed DPA achieves an adjacent channel leakage ratio of -45.8 dBc with an output power of 36.1 dBm at 2.0 GHz after digital predistortion when it is excited by 5-MHz WCDMA signal with a peaking-to-average power ratio of 8.6 dB.
Increasing seed oil content is one of the most important breeding goals for soybean due to a high global demand for edible vegetable oil. However, genetic improvement of seed oil content has been ...difficult in soybean because of the complexity of oil metabolism. Determining the major variants and molecular mechanisms conferring oil accumulation is critical for substantial oil enhancement in soybean and other oilseed crops. In this study, we evaluated the seed oil contents of 219 diverse soybean accessions across six different environments and dissected the underlying mechanism using a high-resolution genome-wide association study (GWAS). An environmentally stable quantitative trait locus (QTL), GqOil20, significantly associated with oil content was identified, accounting for 23.70% of the total phenotypic variance of seed oil across multiple environments. Haplotype and expression analyses indicate that an oleosin protein-encoding gene (GmOLEO1), colocated with a leading single nucleotide polymorphism (SNP) from the GWAS, was significantly correlated with seed oil content. GmOLEO1 is predominantly expressed during seed maturation, and GmOLEO1 is localized to accumulated oil bodies (OBs) in maturing seeds. Overexpression of GmOLEO1 significantly enriched smaller OBs and increased seed oil content by 10.6% compared with those of control seeds. A time-course transcriptomics analysis between transgenic and control soybeans indicated that GmOLEO1 positively enhanced oil accumulation by affecting triacylglycerol metabolism. Our results also showed that strong artificial selection had occurred in the promoter region of GmOLEO1, which resulted in its high expression in cultivated soybean relative to wild soybean, leading to increased seed oil accumulation. The GmOLEO1 locus may serve as a direct target for both genetic engineering and selection for soybean oil improvement.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this letter, the bandwidth of the series of continuous modes (SCMs) power amplifiers (PAs) is extended. The SCMs are composed of a series of continuous working modes between Class-B/J and Class-F ...continuums. The second harmonic load of the series of continuums is purely reactive. By introducing resistive part to the purely reactive second harmonic load of the series of continuous modes, the operation bandwidth of power amplifiers is expanded. A broadband PA working across 0.8-3.05 GHz (117% bandwidth) is simulated and fabricated. Experimental results show that the drain efficiencies in interesting band are 57.4%-79%. The fabricated PA can deliver output power of 10.1-20.7 W.
Catheter-related bloodstream infections (CRBSIs) are a significant cause of morbidity and mortality in critically ill patients, contributing to prolonged hospital stays and increased costs. Whether ...taurolidine lock solutions (TLS) are beneficial for the prevention of CRBSIs remains controversial. In this meta-analysis, we aim to assess the efficacy of TLS for preventing CRBSIs.
We conducted a systematic search of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Eligible studies included randomized controlled trials that reported on the effects of TLS for preventing CRBSIs. The primary outcome in these studies was catheter-related bloodstream infections, with microbial distribution of CRBSI and catheter-associated thrombosis as secondary outcomes. Data were combined using random-effects models owing to significant clinical heterogeneity.
Six randomized controlled trials (RCTs) conducted from 2004 through 2013 involving 431 patients and 86,078 catheter-days were included in the review. TLS were significantly associated with a lower incidence of CRBSIs when compared to heparin lock solutions (Risk Ratio RR, 0.34; 95% Confidence Interval CI, 0.21-0.55). Use of TLS significantly decreased the incidence of CRBSIs from gram-negative (G-) bacteria (P = 0.004; RR, 0.27; CI, 0.11-0.65), and was associated with a non-significant decrease in gram-positive (G+) bacterial infections (P = 0.07; RR, 0.41; CI, 0.15-1.09). No significant association was observed with TLS and catheter-associated thrombosis (RR, 1.99; CI, 0.75-5.28).
The use of TLS reduced the incidence of CRBSIs without obvious adverse effects or bacterial resistance. However, the susceptibility of G+ and G- bacteria to taurolidine and the risk for catheter-associated thrombosis of TLS are indeterminate due to limited data. The results should be treated with caution due to the limited sample sizes and methodological deficiencies of included studies. Therefore, additional well-designed and adequately powered RCTs are needed to confirm these findings.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•An aerobic denitrifier, P. stutzeri XL-2, was newly isolated.•Strain XL-2 presents great capability to reduce nitrate aerobically.•The production of N2 was much greater than N2O by strain XL-2.•The ...optimal conditions for nitrate removal were investigated.•Denitrification genes of napA, nirS, norB and nosZ were successfully amplified.
An aerobic denitrifier was newly isolated and identified as Pseudomonas stutzeri strain XL-2. Strain XL-2 removed 97.9% of nitrate with an initial concentration about 100 mg/L. Nitrogen balance indicates that 12.4% of the initial nitrogen was converted to N2O, and 62.4% was converted to N2. Single factor experiments indicate that the optimal conditions for nitrate removal were C/N ratio of 10, temperature of 30 °C and shaking speed of 120 rpm. Sequence amplification indicates that the denitrification genes of napA, nirS, norB and nosZ were present in strain XL-2. Combined with nitrogen balance, strain XL-2 presents the metabolic pathway of NO3− → NO2− → NO → N2O → N2 under aerobic conditions. The expression of napA and nirS might be responsible for the tolerance of dissolved oxygen by strain XL-2 during denitrification process.
Polysaccharides are a major class of biomacromolecules. Their bioactivities depend on chemical structure, which includes monosaccharide composition, linkages below sugar residues, and solution ...conformation. Many researchers report that chemical modifications of polysaccharides lead to a significantly increase in the structural diversity, promoting bioactivity and even add new bioactivities, including antioxidant and anti-tumor properties as well as anticoagulant and immunoregulatory activities. This paper reviews the recent progress of chemical modification of polysaccharides, including i) the common synthetic methods of chemical modification; ii) their structural characterization; iii) their bioactivities; and iv) the structure activity relationships of these modified polysaccharides. This review also suggests future directions for researchers and new applications for chemically modified polysaccharide derivatives in the pharmaceutical and food industries.
•Chemically modified polysaccharides of the past two decades of online review research.•These generalizations are better for people to understand the research status of chemical modified polysaccharides.•This review suggests future directions and new applications for researchers and in the pharmaceutical and food industries.
Seed development is programmed by expression of many genes in plants. Seed maturation is an important developmental process to soybean seed quality and yield. DNA methylation is a major epigenetic ...modification regulating gene expression. However, little is known about the dynamic nature of DNA methylation and its effects on gene expression during plant development. Through whole-genome bisulfite sequencing, we showed that DNA methylation went through dynamic changes during seed maturation. An average of 66% CG, 45% CHG and 9% CHH contexts was methylated in cotyledons. CHH methylation levels in cotyledons changed greatly from 6% at the early stage to 11% at the late stage. Transcribed genes were approximately two-fold more likely to be differentially methylated than non-transcribed genes. We identified 40, 66 and 2136 genes containing differentially methylated regions (DMRs) with negative correlation between their expression and methylation in the CG, CHG and CHH contexts, respectively. The majority of the DMR genes in the CHH context were transcriptionally down-regulated as seeds mature: 99% of them during early maturation were down-regulated, and preferentially associated with DNA replication and cell division. The results provide novel insights into the dynamic nature of DNA methylation and its relationship with gene regulation in seed development.
Among the approximately 20 million patients with drug‐resistant epilepsy (DRE) worldwide, the vast majority can benefit from surgery to minimize seizure reduction and neurological impairment. Precise ...preoperative localization of epileptogenic zone (EZ) and complete resection of the lesions can influence the postoperative prognosis. However, precise localization of EZ is difficult, and the structural and functional alterations in the brain caused by DRE vary by etiology. Neuroimaging has emerged as an approach to identify the seizure‐inducing structural and functional changes in the brain, and magnetic resonance imaging (MRI) and positron emission tomography (PET) have become routine noninvasive imaging tools for preoperative evaluation of DRE in many epilepsy treatment centers. Multimodal neuroimaging offers unique advantages in detecting EZ, especially in improving the detection rate of patients with negative MRI or PET findings. This approach can characterize the brain imaging characteristics of patients with DRE caused by different etiologies, serving as a bridge between clinical and pathological findings and providing a basis for individualized clinical treatment plans. In addition to the integration of multimodal imaging modalities and the development of special scanning sequences and image post‐processing techniques for early and precise localization of EZ, the application of deep machine learning for extracting image features and deep learning‐based artificial intelligence have gradually improved diagnostic efficiency and accuracy. These improvements can provide clinical assistance for precisely outlining the scope of EZ and indicating the relationship between EZ and functional brain areas, thereby enabling standardized and precise surgery and ensuring good prognosis. However, most existing studies have limitations imposed by factors such as their small sample sizes or hypothesis‐based study designs. Therefore, we believe that the application of neuroimaging and post‐processing techniques in DRE requires further development and that more efficient and accurate imaging techniques are urgently needed in clinical practice.
Level of Evidence
5
Technical Efficacy
Stage 2
A novel strain AL-6, which was identified as Acinetobacter baumannii, presented an efficient ability to remove ammonium. Nitrogen balance indicates that 55.8% of the initial NH4+–N was ultimately ...converted to N2 through heterotrophic nitrification and aerobic denitrification, while 30.6% was contributed to assimilation. More interestingly, efficient ammonium removal could be achieved in the presence of Cr(VI) of 0–10 mg L−1 by strain AL-6. Meanwhile, Cr(VI) reduction was observed. The Cr(VI) was mainly reduced to less toxic Cr(III) by strain AL-6 in the culture, while a small part of Cr(VI) might be accumulated in bacterial cells in the formation of Cr(III). The optimal conditions for ammonium removal as well as Cr(VI) reduction was pH of 7 and C/N ratio of 10–15. This study provided a potential prospect for the treatment of Cr(VI)-containing ammonium wastewater.
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