Plant atmospheric CO
2
fixation depends on the aperture of stomatal pores at the leaf epidermis. Stomatal aperture or closure is regulated by changes in the metabolism of the two surrounding guard ...cells, which respond directly to environmental and internal cues such as mesophyll-derived metabolites. Sucrose has been shown to play a dual role during stomatal movements. The sucrose produced in the mesophyll cells can be transported to the vicinity of the guard cells via the transpiration stream, inducing closure in periods of high photosynthetic rate. By contrast, sucrose breakdown within guard cells sustains glycolysis and glutamine biosynthesis during light-induced stomatal opening. Here, we provide an update regarding the role of sucrose in the regulation of stomatal movement highlighting recent findings from metabolic and systems biology studies. We further explore how sucrose-mediated mechanisms of stomatal movement regulation could be useful to understand evolution of stomatal physiology among different plant groups.
Background:
A single-item self-rated diet measure (SRD) may provide a quick, low-burden screener. However, assessment of its validity is limited. This study aimed to evaluate the association of an ...SRD construct with measured diet quality among adults in Puerto Rico (PR).
Methodology:
Participants (30–75 years old;
n
= 247) of the PR Assessment of Diet, Lifestyle, and Diseases (PRADLAD) cross-sectional study reported SRD with a single question (“How would you describe your current dietary habits and diet quality?”) with a five-point scale: excellent to poor. More complete diet quality was calculated using the Alternate Healthy Eating Index-2010 (AHEI), with 11 food and nutrient components assessed by the food frequency questionnaire. Multivariable general linear models were used to test associations between SRD with AHEI and its components. Associations were also tested between recall SRD in youth and current AHEI.
Results:
Most participants (35.2%) self-rated diet as “good,” 13.8% as “excellent,” and 4.1% as “poor,” with the remainder split between middle scale points. SRD was not significantly associated with AHEI, although participants with “excellent” vs. “poor” SRD had marginally higher AHEI (
P
= 0.07). SRD was significantly associated with higher fruit intake (
P
= 0.02) and marginally associated with intakes of vegetables (
P
= 0.07) and long-chain fatty acids (
P
= 0.07). Unexpectedly, AHEI was significantly higher among those reporting “poor” SRD in young adulthood (
P
= 0.01) or childhood (
P
= 0.05).
Conclusions:
SRD may capture current diet quality at extreme intakes. Larger studies should confirm these findings and replicate them in other underrepresented populations. Further research should clarify the inverse associations between adult AHEI and earlier reported SRD.
To characterize the molecular changes that occur in normal fibroblasts, adhesion fibroblasts, and mesothelial cells as a result of exposure to modified hyaluronic acid and carboxymethylcellulose ...(Seprafilm).
University research laboratory.
Human mesothelial and fibroblast cell culture.
Multiplex reverse transcriptase polymerase chain reaction was used to examine control and Seprafilm-treated normal peritoneal fibroblasts, adhesion fibroblasts, and mesothelial cells in culture for levels of messenger RNA from molecules known to be associated with adhesion development (transforming growth factor-β1, type I collagen, matrix metalloproteinase-1, matrix metalloproteinase-2, tissue inhibitor of metalloproteinase-1, and tissue plasminogen activator).
Seprafilm treatment of normal peritoneal fibroblasts, adhesion fibroblasts and mesothelial cells did not alter the expression of markers examined.
In the absence of a biological effect of Seprafilm on markers known to be involved in postoperative adhesion development, the ability of Seprafilm to reduce postoperative adhesions is most likely caused by its effect as a physical barrier.
A series of lamellarin derivatives have been studied as topoisomerase I (Top1) inhibitors. Molecular models of the ternary complexes formed between the DNA-Top1 ensemble and lamellarin D (LMD) or ...camptothecin (CPT) fully intercalated into the duplex DNA have been built and studied by means of nanosecond molecular dynamics simulations in aqueous solution. Our results show that the 20-OH and 8-OH of LMD can participate in hydrogen-bonding interactions with the side chains of Glu356 and Asn722, respectively, the latter being consistent with the finding that CEM/C2 cells, which are resistant to CPT, are cross-resistant to LMD. Our models also account for the observation that LMD stabilizes Top1 cleavage at CG sites in addition to the TG sites observed for CPT and rationalize the structure−activity relationships within the series. The deleterious effect of replacing the 20-OH in LMD with a hydrogen was confirmed using a set of thermodynamic integration free energy simulations.
Background
Pathological response to neoadjuvant chemotherapy (NAC) is critical in prognosis and selection of systemic treatments for patients with triple-negative breast cancer (TNBC). The aim of ...this study is to identify gene expression-based markers to predict response to NAC.
Patients and Methods
A survey of 43 publicly available gene expression datasets was performed. We identified a cohort of TNBC patients treated with NAC (
n
= 708). Gene expression data from different studies were renormalized, and the differences between pretreatment (pre-NAC), on-treatment (post-C1), and surgical (Sx) specimens were evaluated. Euclidean statistical distances were calculated to estimate changes in gene expression patterns induced by NAC. Hierarchical clustering and pathway enrichment analyses were used to characterize relationships between differentially expressed genes and affected gene pathways. Machine learning was employed to refine a gene expression signature with the potential to predict response to NAC.
Results
Forty nine genes consistently affected by NAC were involved in enhanced regulation of wound response, chemokine release, cell division, and decreased programmed cell death in residual invasive disease. The statistical distances between pre-NAC and post-C1 significantly predicted pathological complete response area under the curve (AUC) = 0.75;
p
= 0.003; 95% confidence interval (CI) 0.58–0.92. Finally, the expression of
CCND1
, a cyclin that forms complexes with CDK4/6 to promote the cell cycle, was the most informative feature in pre-NAC biopsies to predict response to NAC.
Conclusions
The results of this study reveal significant transcriptomic changes induced by NAC and suggest that chemotherapy-induced gene expression changes observed early in therapy may be good predictors of response to NAC.
Alcohol consumption is considered a major risk factor for disease and mortality worldwide. In the absence of effective treatments in alcohol use disorders, it is important to find new biological ...targets that could modulate alcohol consumption. We tested the role of the N‐terminal galanin fragment (1–15) GAL(1–15) in voluntary ethanol consumption in rats using the two‐bottle choice paradigm as well as compare the effects of GAL(1–15) with the whole molecule of GAL. We describe for the first time that GAL(1–15), via central mechanisms, induces a strong reduction in preference and ethanol consumption in rats. These effects were significantly different than GAL. GAL receptor (GALR) 2 was involved in these effects, because the specific GALR2 antagonist M871 blocked GAL(1–15) mediated actions in preference and ethanol intake. Importantly, the mechanism of this action involves changes in GALR expression and also in immediate‐early gene C‐Fos and receptors‐internalization‐related gene Rab5 in the striatum. The relevance of the striatum as a target for GAL(1–15) was supported by the effect of GAL(1–15) on the locomotor activity of rats after ethanol administration. These results may give the basis for the development of novel therapeutics strategies using GAL(1–15) analogues for the treatment of alcohol use disorders in humans.
The N‐terminal fragment GAL(1–15) induces a strong reduction in preference and ethanol consumption in rats. The mechanism of this action involves changes in striatum in GAL receptors expression and also in immediate‐early gene C‐Fos and receptors‐internalization‐related gene Rab5.
In this work, we compared the unique artificial neural networks (ANNs) technology with the usual statistical analysis to establish its utility as an alternative methodology in plant research. For ...this purpose, we selected a simple
in vitro proliferation experiment with the aim of evaluating the effects of light intensity and sucrose concentration on the success of the explant proliferation and finally, of optimizing the process taking into account any influencing factors. After data analysis, the traditional statistical procedure and ANNs technology both indicated that low light treatments and high sucrose concentrations are required for the highest kiwifruit microshoot proliferation under experimental conditions. However, this particular ANNs software is able to model and optimize the process to estimate the best conditions and does not need an extremely specialized background. The potential of the ANNs approach for analyzing plant biology processes, in this case, plant tissue culture data, is discussed.
A combination of variable temperature scanning tunneling microscopy, near edge X-ray adsorption fine structure and density functional theory has been used to investigate the chemisorption and ...self-assembly of metal-free protoporphyrin IX molecules on Cu(110) surface. The molecules in contact with the substrate suffer irreversible molecular transformations, mainly deprotonation of the carboxylic groups and metalation of the pyrroline subunits. The carboxylate group has been revealed as the anchored group versus the tetrapyrrole ring. We study the role played by the carboxylic acid groups in the surface-molecular bonding and how its presence affects the supramolecular structure.
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