The complex relationship between ontogeny and phylogeny has been the subject of attention and controversy since von Baer's formulations in the 19th century. The classic concept that embryogenesis ...progresses from clade general features to species-specific characters has often been revisited. It has become accepted that embryos from a clade show maximum morphological similarity at the so-called phylotypic period (i.e., during mid-embryogenesis). According to the hourglass model, body plan conservation would depend on constrained molecular mechanisms operating at this period. More recently, comparative transcriptomic analyses have provided conclusive evidence that such molecular constraints exist. Examining cis-regulatory architecture during the phylotypic period is essential to understand the evolutionary source of body plan stability. Here we compare transcriptomes and key epigenetic marks (H3K4me3 and H3K27ac) from medaka (Oryzias latipes) and zebrafish (Danio rerio), two distantly related teleosts separated by an evolutionary distance of 115-200 Myr. We show that comparison of transcriptome profiles correlates with anatomical similarities and heterochronies observed at the phylotypic stage. Through comparative epigenomics, we uncover a pool of conserved regulatory regions (≈700), which are active during the vertebrate phylotypic period in both species. Moreover, we show that their neighboring genes encode mainly transcription factors with fundamental roles in tissue specification. We postulate that these regulatory regions, active in both teleost genomes, represent key constrained nodes of the gene networks that sustain the vertebrate body plan.
FtsZ is a widely conserved tubulin-like GTPase that directs bacterial cell division and a new target for antibiotic discovery. This protein assembly machine cooperatively polymerizes forming ...single-stranded filaments, by means of self-switching between inactive and actively associating monomer conformations. The structural switch mechanism was proposed to involve a movement of the C-terminal and N-terminal FtsZ domains, opening a cleft between them, allosterically coupled to the formation of a tight association interface between consecutive subunits along the filament. The effective antibacterial benzamide PC190723 binds into the open interdomain cleft and stabilizes FtsZ filaments, thus impairing correct formation of the FtsZ ring for cell division. We have designed fluorescent analogs of PC190723 to probe the FtsZ structural assembly switch. Among them, nitrobenzoxadiazole probes specifically bind to assembled FtsZ rather than to monomers. Probes with several spacer lengths between the fluorophore and benzamide moieties suggest a binding site extension along the interdomain cleft. These probes label FtsZ rings of live
and
, without apparently modifying normal cell morphology and growth, but at high concentrations they induce impaired bacterial division phenotypes typical of benzamide antibacterials. During the FtsZ assembly-disassembly process, the fluorescence anisotropy of the probes changes upon binding and dissociating from FtsZ, thus reporting open and closed FtsZ interdomain clefts. Our results demonstrate the structural mechanism of the FtsZ assembly switch, and suggest that the probes bind into the open clefts in cellular FtsZ polymers preferably to unassembled FtsZ in the bacterial cytosol.
Focused femtosecond laser pulses have been used to modify the optical properties of glass doped with CdSxSe1-x nanocrystals. Large positive refractive index changes have been observed and exploited ...for the fabrication of photonic devices. In particular, we report on highly confining optical waveguides and single and multi-layer volume diffraction gratings.
Our study aimed to identify the prevalence and severity of gastrointestinal (GI) symptoms and dysphagia in patients with amyotrophic lateral sclerosis (ALS) and to assess whether a correlation exists ...between these symptoms and the severity of ALS progression.
The presence and severity of GI symptoms and dysphagia were identified by means of the Gastrointestinal Symptom Rating Scale (GSRS) and the Functional Outcome Swallowing Scale (FOSS). The Revised ALS Functional Rating Scale (ALSFRS-R) was utilized to determine the severity of ALS. Analysis of data was performed with Spearman correlations in semi-qualitative variables of clinical scales. ALSFRS-R scores were divided into 2 categories: those with mild to moderate ALS (≥40-30 points) and patients with moderate to advanced ALS (29-≤20 points).
We studied 43 patients with definite ALS. The most frequent GI symptoms were constipation (60.5%), rectal tenesmus (57.5%), hard stools (55.0%), and borborygmus (42.5%). The moderate to advanced ALS stage was correlated with constipation (r = 0.334; p = 0.028), acid regurgitation (r = 0.384; p = 0.013), eructation (r = 0.334; p = 0.032), rectal tenesmus (r = 0.498; p = 0.001), and functional dysphagia (r = 0.656; p = <0.001).
Early detection of these GI symptoms can guide timely therapeutic decisions to avoid weight loss, a predictor for worse prognosis. This study highlights the relevance of the detection of these symptoms in ALS patients who score ≤29 points in the ALSFRS-R scale to establish an appropriate treatment, prevent systemic complications, provide more comfort, and improve quality of life.
The particular features of gold have generated widespread interest for applications in different areas of science and technology. Notably, gold nanoparticles can be prepared with different sizes and ...forms and can be easily functionalized with a wide range of ligands. Developing effective experimental techniques to characterize such properties is thus important. In this work, photoacoustic spectroscopy was used to explore the relationship between the nanoparticle size and the optical absorption coefficient (at 405 nm and 532 nm) of gold colloid solutions, according to the Beer–Lambert’s law. A correlation between this optical parameter and the nanoparticle size was found. In addition, for comparison purposes, conventional UV–visible spectroscopy was used for measuring the absorbance at these two wavelengths. Very good agreement was obtained between the optical properties measured by the two methodologies at 405 nm. However, large discrepancies were obtained when measurements were performed at 532 nm. At the latter wavelength, the extent of radiation dispersion is too large for the Beer–Lambert’s law to be valid when the conventional spectroscopy technique is used. Unlike the UV–visible spectroscopy, the photoacoustic method is minimally affected by radiation dispersion effects. Thus, the photoacoustic method presents fewer limitations in that regard in characterizing the optical properties of metallic colloidal suspensions.
Maternal nutrition during gestation has important effects on gene expression-mediated metabolic programming in offspring. To evaluate the effect of a protein-restricted maternal diet during ...gestation, pancreatic islets from male progeny of Wistar rats were studied at postnatal days (PND) 36 (juveniles) and 90 (young adults). The expression of key genes involved in β-cell function and the DNA methylation pattern of the regulatory regions of two such genes,
(pancreatic and duodenal homeobox 1) and
(musculoaponeurotic fibrosarcoma oncogene family, protein A), were investigated. Gene expression analysis in the pancreatic islets of restricted offspring showed significant differences compared with the control group at PND 36 (
< 0.05). The insulin 1 and 2 (
and
),
(glucose transporter 2),
, and
(activating transcription factor 2), genes were upregulated, while glucokinase (
) and
(neuronal differentiation 1) were downregulated. Additionally, we studied whether the gene expression differences in
and
between control and restricted offspring were associated with differential DNA methylation status in their regulatory regions. A decrease in the DNA methylation levels was found in the 5' flanking region between nucleotides -8118 to -7750 of the
regulatory region in restricted offspring compared with control pancreatic islets. In conclusion, low protein availability during gestation causes the upregulation of
gene expression in pancreatic β-cells in the male juvenile offspring at least in part through DNA hypomethylation. This process may contribute to developmental dysregulation of β-cell function and influence the long-term health of the offspring.
Abstract
Non‐linear excitation microscopy offers several advantages for in‐vivo imaging compared to conventional confocal techniques. However, tissue penetration can still be an issue due to ...scattering and spherical aberrations induced on focused beams by the tissue. The use of low numerical aperture objectives to pass through the outer layers of the skin, together with high dioptric power microlenses implanted in‐vivo close to the observation volume, can be beneficial to the reduction of optical aberrations. Here, Fibroblast cell culture plano‐convex microlenses to be used for non‐linear imaging of biological tissue are developed and tested. The microlenses can be used as single lenses or multiplexed in an array. A thorough test of the lenses wavefront is reported together with the modulation transfer function and wavefront profile. Magnified fluorescence images can be retrieved through the microlenses coupled to commercial confocal and two‐photon excitation scanning microscopes. The signal‐to‐noise ratio of the images is not substantially affected by the use of the microlenses and the magnification can be adjusted by changing the relative position of the microlens array to the microscope objective and the immersion medium. These results are opening the way to the application of implanted micro‐optics for optical in‐vivo inspection of biological processes.
Indoor air pollution is considered to be a serious public health issue in Mexico; therefore, more studies regarding this topic are necessary. In this context, we assessed exposure to polycyclic ...aromatic hydrocarbons (PAHs) and volatile organic compounds in: (i) women who use firewood combustion (indoor) for cooking and heating using traditional open fire; (ii) women who use firewood combustion (outdoor) for cooking and heating using traditional open fire; and (iii) women who use LP gas as the principal energy source. We studied 96 healthy women in San Luis Potosi, México. Urine samples were collected, and analyses of the following urinary exposure biomarkers were performed by high‐performance liquid chromatography: 1‐hydroxypyrene (1‐OHP), trans, trans‐muconic acid, and hippuric acid (HA). The highest levels of 1‐OHP, trans, trans‐muconic acid, and HA were found in communities where women were exposed to indoor biomass combustion smoke (or products; geometric mean ± s.d., 3.98 ± 5.10 μmol/mol creatinine; 4.81 ± 9.60 μg/l 1‐OHP; 0.87 ± 1.78 mg/g creatinine for trans, trans‐muconic acid; and 1.14 ± 0.91 g/g creatinine for HA). Our findings indicate higher exposure levels to all urinary exposure biomarkers studied in women who use indoor firewood combustion for cooking and heating (using traditional open fire).
Practical Implications
High mean levels of 1‐hydroxypyrene, t,t‐muconic acid, and hippuric acid were found in women who use firewood combustion (indoor) for cooking and heating using traditional open fire and taking into account that millions of women and children in Mexico are living in scenarios similar to those studied in this report, the assessment of health effects in women and children exposed to polycyclic aromatic hydrocarbons and volatile organic compounds is urgently needed. Moreover, it is immediately necessary an intervention program to reduce exposure.
Aims: Cannabinoids are known to control energy homeostasis. Atypical cannabinoids produce pharmacological effects via unidentified targets. We sought to investigate whether the atypical cannabinoid ...O‐1602 controls food intake and body weight.
Methods: The rats were injected acutely or subchronically with O‐1602, and the expression of several factors involved in adipocyte metabolism was assessed by real‐time polymerase chain reaction. In vivo findings were corroborated with in vitro studies incubating 3T3‐L1 adipocytes with O‐1602, and measuring intracellular calcium and lipid accumulation. Finally, as some reports suggest that O‐1602 is an agonist of the putative cannabinoid receptor GPR55, we tested it in mice lacking GPR55.
Results: Central and peripheral administration of O‐1602 acutely stimulates food intake, and chronically increases adiposity. The hyperphagic action of O‐1602 is mediated by the downregulation of mRNA and protein levels of the anorexigenic neuropeptide cocaine‐ and amphetamine‐regulated transcript. The effects on fat mass are independent of food intake, and involve a decrease in the expression of lipolytic enzymes such as hormone sensitive lipase and adipose triglyceride lipase in white adipose tissue. Consistently, in vitro data showed that O‐1602 increased the levels of intracellular calcium and lipid accumulation in adipocytes. Finally, we injected O‐1602 in GPR55 −/− mice and found that O‐1602 was able to induce feeding behaviour in GPR55‐deficient mice.
Conclusions: These findings show that O‐1602 modulates food intake and adiposity independently of GPR55 receptor. Thus atypical cannabinoids may represent a novel class of molecules involved in energy balance.
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