QTLs and Candidate Loci Associated with Drought Tolerance Traits of Kaybonnet x ZHE733 Recombinant Inbred Lines Rice Population.

Rice is the most important staple crop for the sustenance of the world's population, and drought is a major factor limiting rice production. Quantitative trait locus (QTL) analysis of drought-resistance-related traits was conducted on a recombinant inbred line (RIL) population derived from the self-fed progeny of a cross between the drought-resistant tropical japonica U.S. adapted cultivar Kaybonnet and the drought-sensitive indica cultivar ZHE733. K/Z RIL population of 198 lines was screened in the field at Fayetteville (AR) for three consecutive years under controlled drought stress (DS) and well-watered (WW) treatment during the reproductive stage. The effects of DS were quantified by measuring morphological traits, grain yield components, and root architectural traits. A QTL analysis using a set of 4133 single nucleotide polymorphism (SNP) markers and the QTL IciMapping identified 41 QTLs and 184 candidate genes for drought-related traits within the DR-QTL regions. RT-qPCR in parental lines was used to confirm the putative candidate genes. The comparison between the drought-resistant parent (Kaybonnet) and the drought-sensitive parent (ZHE733) under DS conditions revealed that the gene expression of 15 candidate DR genes with known annotations and two candidate DR genes with unknown annotations within the DR-QTL regions was up-regulated in the drought-resistant parent (Kaybonnet). The outcomes of this research provide essential information that can be utilized in developing drought-resistant rice cultivars that have higher productivity when DS conditions are prevalent.

Molecular mapping and characterization of QTLs for grain quality traits in a RIL population of US rice under high nighttime temperature stress.

Elevated nighttime temperatures resulting from climate change significantly impact the rice crop worldwide. The rice (Oryza sativa L.) plant is highly sensitive to high nighttime temperature (HNT) during grain-filling (reproductive stage). HNT stress negatively affects grain quality traits and has a major impact on the value of the harvested rice crop. In addition, along with grain dimensions determining rice grain market classes, the grain appearance and quality traits determine the rice grain market value. During the last few years, there has been a major concern for rice growers and the rice industry over the prevalence of rice grains opacity and the reduction of grain dimensions affected by HNT stress. Hence, the improvement of heat-stress tolerance to maintain grain quality of the rice crop under HNT stress will bolster future rice value in the market. In this study, 185 F12-recombinant inbred lines (RILs) derived from two US rice cultivars, Cypress (HNT-tolerant) and LaGrue (HNT-sensitive) were screened for the grain quality traits grain length (GL), grain width (GW), and percent chalkiness (%chalk) under control and HNT stress conditions and evaluated to identify the genomic regions associated with the grain quality traits. In total, there were 15 QTLs identified; 6 QTLs represented under control condition explaining 3.33% to 8.27% of the phenotypic variation, with additive effects ranging from - 0.99 to 0.0267 on six chromosomes and 9 QTLs represented under HNT stress elucidating 6.39 to 51.53% of the phenotypic variation, with additive effects ranging from - 8.8 to 0.028 on nine chromosomes for GL, GW, and % chalk. These 15 QTLs were further characterized and scanned for natural genetic variation in a japonica diversity panel (JDP) to identify candidate genes for GL, GW, and %chalk. We found 6160 high impact single nucleotide polymorphisms (SNPs) characterized as such depending on their type, region, functional class, position, and proximity to the gene and/or gene features, and 149 differentially expressed genes (DEGs) in the 51 Mbp genomic region comprising of the 15 QTLs. Out of which, 11 potential candidate genes showed high impact SNP associations. Therefore, the analysis of the mapped QTLs and their genetic dissection in the US grown Japonica rice genotypes at genomic and transcriptomic levels provide deep insights into genetic variation beneficial to rice breeders and geneticists for understanding the mechanisms related to grain quality under heat stress in rice.

Identification of Genomic Regions Controlling Chalkiness and Grain Characteristics in a Recombinant Inbred Line Rice Population Based on High-Throughput SNP Markers.

Rice (Oryza sativa L.) is the primary food for half of the global population. Recently, there has been increasing concern in the rice industry regarding the eating and milling quality of rice. This study was conducted to identify genetic information for grain characteristics using a recombinant inbred line (RIL) population from a japonica/indica cross based on high-throughput SNP markers and to provide a strategy for improving rice quality. The RIL population used was derived from a cross of "Kaybonnet (KBNT lpa)" and "ZHE733" named the K/Z RIL population, consisting of 198 lines. A total of 4133 SNP markers were used to identify quantitative trait loci (QTLs) with higher resolution and to identify more accurate candidate genes. The characteristics measured included grain length (GL), grain width (GW), grain length to width ratio (RGLW), hundred grain weight (HGW), and percent chalkiness (PC). QTL analysis was performed using QTL IciMapping software. Continuous distributions and transgressive segregations of all the traits were observed, suggesting that the traits were quantitatively inherited. A total of twenty-eight QTLs and ninety-two candidate genes related to rice grain characteristics were identified. This genetic information is important to develop rice varieties of high quality.

Distending Media Used During Hysteroscopy: Perioperative Nursing Implications.

Hysteroscopy is a gynecological procedure that may be indicated for abnormal uterine bleeding, diagnosis and management of infertility, contraception, or sterilization. Surgeons use distending media during hysteroscopy to view the uterine cavity. Media options include carbon dioxide gas and both electrolytic and nonelectrolytic fluids. All distending media is absorbed by the patient's body, but the manner in which each media is absorbed is unique to its chemical composition. Understanding the properties of each distending medium and the risks involved with its use is critical to safe perioperative nursing care for patients undergoing hysteroscopy. This article provides perioperative nurses with a review of uterine anatomy and evidence-based information on the types of distending media used during hysteroscopy and the corresponding perioperative nursing implications.

Mix and Match: Coassembly of Amphiphilic Dendrimers and Phospholipids Creates Robust, Modular, and Controllable Interfaces.

Self-assembly of supramolecular structures has become an attractive means to create new biologically inspired materials and interfaces. We report the first robust hybrid bilayer systems readily coassembled from amphiphilic dendrimers and a naturally occurring phospholipid. Both concentration and generation of the dendrimers have direct impacts on the biophysical properties of the coassemblies. Raising the dendrimer concentration increases the hybrid bilayer stability, while changes in the generation and the concentration of the embedded dendrimers impact the fluidity of the coassembled systems. Multivalent dendrimer amine terminals allow for nondestructive in situ derivatization, providing a convenient approach to decorate and modulate the local environment of the hybrid bilayer. The coassembly of lipid/dendrimer interfaces offers a unique platform for the creation of hybrid systems with modular and precisely controllable behavior for further applications in sensing and drug delivery.

On-Demand Formation of Supported Lipid Membrane Arrays by Trehalose-Assisted Vesicle Delivery for SPR Imaging.

The fabrication of large-scale, solid-supported lipid bilayer (SLB) arrays has traditionally been an arduous and complex task, primarily due to the need to maintain SLBs within an aqueous environment. In this work, we demonstrate the use of trehalose vitrified phospholipid vesicles that facilitate on-demand generation of microarrays, allowing each element a unique composition, for the label-free and high-throughput analysis of biomolecular interactions by SPR imaging (SPRi). Small, unilamellar vesicles (SUVs) are suspended in trehalose, deposited in a spatially defined manner, with the trehalose vitrifying on either hydrophilic or hydrophobic SPR substrates. SLBs are subsequently spontaneously formed on-demand simply by in situ hydration of the array in the SPR instrument flow cell. The resulting SLBs exhibit high lateral mobility, characteristic of fluidic cellular lipid membranes, and preserve the biological function of embedded cell membrane receptors, as indicated by SPR affinity measurements. Independent fluorescence and SPR imaging studies show that the individual SLBs stay localized at the area of deposition, without any encapsulating matrix, confining coral, or boundaries. The introduced methodology allows individually addressable SLB arrays to be analyzed with excellent label-free sensitivity in a real-time, high-throughput manner. Various protein-ganglioside interactions have been selected as a model system to illustrate discrimination of strong and weak binding responses in SPRi sensorgrams. This methodology has been applied toward generating hybrid bilayer membranes on hydrophobic SPR substrates, demonstrating its versatility toward a range of surfaces and membrane geometries. The stability of the fabricated arrays, over medium to long storage periods, was evaluated and found to be good. The highly efficient and easily scalable nature of the method has the potential to be applied to a variety of label-free sensing platforms requiring lipid membranes for high-throughput analysis of their properties and constituents.

Synthesis, characterization, and antitumor activity of unusual pseudo five coordinate gold(III) complexes: distinct cytotoxic mechanism or expensive ligand delivery systems?

Gold(III) complexes bearing bidentate ligands based on the 1,10-phenanthroline and 2,2'-bipyridine scaffolds have shown promising anticancer activity against a variety of tumor cell lines. In particular, our laboratory has previously found that a pseudo five coordinate gold(III) complex possessing the 2,9-di-sec-butyl-1,10-phenanthroline ligand {[((di-sec-butyl)phen)AuCl3]} exhibits antitumor activity against a panel of five different lung and head-neck tumor cell lines. However, the [((di-sec-butyl)phen)AuCl3] complex was determined to be less active than the free 2,9-di-sec-butyl-1,10-phenanthroline ligand. In order to determine if this class of gold(III) complexes has a distinct mechanism of initiating tumor cell death or if these gold complexes simply release the polypyridyl ligand in the intracellular environment, structural analogues of the [((di-sec-butyl)phen)AuCl3] complex have been synthesized and structurally characterized. These structural congeners were prepared by using mono-alkyl and di-phenyl substituted 1,10-phenanthroline ligands, di-alkyl and di-phenyl substituted 4-methyl-1,10-phenanthroline ligands, and mono-alkyl 2,2'-bipyridine ligands. The redox stability of this library of distorted square pyramidal gold(III) complexes has been studied and the in vitro antitumor activity of gold(III) complexes and corresponding polypyridyl ligands has been determined. The [((di-n-butyl)phen)AuCl3] and [((mono-n-butyl)phen)AuCl3] complexes have been found to be significantly more potent at inhibiting the growth of A549 lung tumor cells than the clinically used drug cisplatin. More importantly, these two gold(III) complexes are significantly more active than their respective free ligands, providing evidence that this class of pseudo five coordinate gold(III) complexes has a mechanism of initiating tumor cell death that is independent of the free ligand.

Synthesis, characterization, and stability of iron (III) complex ions possessing phenanthroline-based ligands.

It has previously been demonstrated that phenanthroline-based ligands used to make gold metallotherapuetics have the ability to exhibit cytotoxicity when not coordinated to the metal center. In an effort to help assess the mechanism by which these ligands may cause tumor cell death, iron binding and removal experiments have been considered. The close linkage between cell proliferation and intracellular iron concentrations suggest that iron deprivation strategies may be a mechanism involved in inhibiting tumor cell growth. With the creation of iron (III) phen complexes, the iron binding abilities of three polypyridal ligands [1,10-phenanthroline (phen), 2,9-dimethyl-1, 10-phenanthroline (methylphen), and 2,9-di-sec-butyl-1, 10-phenanthroline ( sec-butylphen)] can be tested via a competition reaction with a known iron chelator. Therefore, iron (III) complexes possessing all three ligands were synthesized. Initial mass spectrometric and infrared absorption data indicate that iron (III) tetrachloride complex ions with protonated phen ligands (RphenH+) were formed: [phenH][FeCl4], [methylphenH][FeCl4], [ sec-butylphenH][FeCl4]. UV-Vis spectroscopy was used to monitor the stability of the complex ions, and it was found that the sec-butylpheniron complex was more stable than the phen and methylphen analogues. This was based on the observation that free ligand was observed immediately upon the addition of EDTA to the [phenH][FeCl4] and [methylphenH] [FeCl4] complex ions.

[Risk factors associated with bronchiolitis in children under 2 years of age]. / Factores de riesgo asociados a bronquiolitis en niños menores de dos años.

INTRODUCTION: The objective of this study was to determine the risk factors associated to bronchiolitis in infants less than two years of age. MATERIALS AND METHODS: Prospective case-control study was performed in a hospital of second level of attention. The sample size was calculated for a level of confidence of 95%, a power of 90%, and a difference of exposure of 15% between cases and controls. For each case, there was one control matched for age and sex. The cases were obtained in the pediatric emergency room and the controls were healthy infants who came to the preventive medicine service of the same hospital. The diagnosis of bronchiolitis was established by direct observation in accordance to clinical criteria and chest X-ray. All the patients were weighed to the moment to be included in the study, and through structured interview the following variables were investigated: family history of bronchial asthma and atopy in immediate family members, prematurity, mechanical ventilation, bronchopulmonary dysplasia, present-day breast-feeding, length of time of breast feeding, early weaning, passive tobacco smoke exposure, maternal smoking, housing and living with domestic animals. The global significance of the study was probed by multiple logistic regression. RESULTS: Were studied 110 pairs with a range of age of 10 days to 23 months (average of 7.1 +/- 4.7 months), 49 pairs were female and 61 male (ratio 1:1.2) The variablés significantly associated (P < or = 0.05) to bronchiolitis were family history of bronchial asthma in immediate family members (OR: 2.9, IC 95% 1.29-6.34) and prematurity (OR: 3.0, IC 95% 1.04-8.87). The early weaning(OR: 0.44, IC 95% 0.24-0.79) and present-day breast-feeding (OR: 0.53, IC 95% 0.30-0.95) revealed a significant negative association. The other studied variables didn't show statistically significant association with bronchiolitis. CONCLUSIONS: Factors that increase the risk of bronchiolitis are a history of prematurity, and family history of bronchial asthma. Factors that have a protective effect are early weaning, and present-day breast-feeding.

Factores de riesgo asociados a bronquiolitis en niños menores de dos años / Risk factors associated with bronchiolitis in children under 2 years of age

INTRODUCTION: The objective of this study was to determine the risk factors associated to bronchiolitis in infants less than two years of age. MATERIALS AND METHODS: Prospective case-control study was performed in a hospital of second level of attention. The sample size was calculated for a level of confidence of 95, a power of 90, and a difference of exposure of 15 between cases and controls. For each case, there was one control matched for age and sex. The cases were obtained in the pediatric emergency room and the controls were healthy infants who came to the preventive medicine service of the same hospital. The diagnosis of bronchiolitis was established by direct observation in accordance to clinical criteria and chest X-ray. All the patients were weighed to the moment to be included in the study, and through structured interview the following variables were investigated: family history of bronchial asthma and atopy in immediate family members, prematurity, mechanical ventilation, bronchopulmonary dysplasia, present-day breast-feeding, length of time of breast feeding, early weaning, passive tobacco smoke exposure, maternal smoking, housing and living with domestic animals. The global significance of the study was probed by multiple logistic regression. RESULTS: Were studied 110 pairs with a range of age of 10 days to 23 months (average of 7.1 +/- 4.7 months), 49 pairs were female and 61 male (ratio 1:1.2) The variablÚs significantly associated (P < or = 0.05) to bronchiolitis were family history of bronchial asthma in immediate family members (OR: 2.9, IC 95 1.29-6.34) and prematurity (OR: 3.0, IC 95 1.04-8.87). The early weaning(OR: 0.44, IC 95 0.24-0.79) and present-day breast-feeding (OR: 0.53, IC 95 0.30-0.95) revealed a significant negative association. The other studied variables didn't show statistically significant association with bronchiolitis. CONCLUSIONS: Factors that increase the risk of bronchiolitis are a history of prematurity, and family history of bronchial asthma. Factors that have a protective effect are early weaning, and present-day breast-feeding.