Neural Responses to Multimodal Ostensive Signals in 5-Month-Old Infants

Infants'' sensitivity to ostensive signals, such as direct eye contact and infant-directed speech, is well documented in the literature. We investigated how infants interpret such signals by assessing common processing mechanisms devoted to them and by measuring neural responses to their compounds. In Experiment 1, we found that ostensive signals from different modalities display overlapping electrophysiological activity in 5-month-old infants, suggesting that these signals share neural processing mechanisms independently of their modality. In Experiment 2, we found that the activation to ostensive signals from different modalities is not additive to each other, but rather reflects the presence of ostension in either stimulus stream. These data support the thesis that ostensive signals obligatorily indicate to young infants that communication is directed to them.     

A Dynamic Gene Regulatory Network Model That Recovers the Cyclic Behavior of Arabidopsis thaliana Cell Cycle

Cell cycle control is fundamental in eukaryotic development. Several modeling efforts have been used to integrate the complex network of interacting molecular components involved in cell cycle dynamics. In this paper, we aimed at recovering the regulatory logic upstream of previously known components of cell cycle control, with the aim of understanding the mechanisms underlying the emergence of the cyclic behavior of such components. We focus on Arabidopsis thaliana, but given that many components of cell cycle regulation are conserved among eukaryotes, when experimental data for this system was not available, we considered experimental results from yeast and animal systems. We are proposing a Boolean gene regulatory network (GRN) that converges into only one robust limit cycle attractor that closely resembles the cyclic behavior of the key cell-cycle molecular components and other regulators considered here. We validate the model by comparing our in silico configurations with data from loss- and gain-of-function mutants, where the endocyclic behavior also was recovered. Additionally, we approximate a continuous model and recovered the temporal periodic expression profiles of the cell-cycle molecular components involved, thus suggesting that the single limit cycle attractor recovered with the Boolean model is not an artifact of its discrete and synchronous nature, but rather an emergent consequence of the inherent characteristics of the regulatory logic proposed here. This dynamical model, hence provides a novel theoretical framework to address cell cycle regulation in plants, and it can also be used to propose novel predictions regarding cell cycle regulation in other eukaryotes.     

Role of lactoferrin and its receptors on biliary epithelium

Human lactoferrin is an iron-binding glycoprotein present at high concentrations in breast milk and colostrum. It is produced by many exocrine glands and widely distributed in a variety of body fluids. This protein has antimicrobial, immunomodulatory, antioxidant, and anticancer properties. Two important hLf receptors have been identified: LDL receptor related protein (LRP1), a low specificity receptor, and intelectin-1 (ITLN1), a high specificity receptor. No data are present on the role of hLf on the biliary epithelium. Our aims have been to evaluate the expression of Lf and its receptors in human and murine cholangiocytes and its effect on proliferation. Immunohistochemistry and immunofluorescence (IF) were conducted on human healthy and primary biliary cholangitis (PBC) liver samples as well as on liver samples obtained from normal and bile duct ligated (BDL) mice to evaluate the expression of Lf, LRP1 and ITLN1. Cell proliferation in vitro studies were performed on human cholangiocyte cell lines via 3-(4,5-dimetiltiazol-2-il)-2,5-diphenyltetrazolium assay as well as IF to evaluate proliferating cell nuclear antigen (PCNA) expression. Our results show that mouse and human cholangiocytes express Lf, LRP1 and ITLN1, at higher extent in cholangiocytes from BDL and PBC samples. Furthermore, the in vitro addition of bovine Lf (bLf) has a proliferative effect on human cholangiocyte cell line. The results support a proliferative role of hLf on the biliary epithelium; this pro-proliferative effect of hLf and bLf on cholangiocytes could be particularly relevant in human cholangiopathies such as PBC, characterized by cholangiocyte death and ductopenia.     

β-1,4-endoglucanases from Talaromyces amestolkiae: Production of glucooligosaccharides from different β-glucans

Abstract

This article presents the purification and characterization of two β-1,4-endoglucanases from Talaromyces amestolkiae. The cellulase activities secreted by this fungus were studied in the presence of different carbon sources, attaining the maximal levels in the presence of Avicel as carbon source. In these conditions, two glycosylated β-1,4-endoglucanases with molecular masses of 25,573?kDa (EG1) and 51,825?kDa (EG2), were purified. Both isoenzymes have acidic isoelectric points, 5.4 and 4.6, respectively. Their optimum pH and temperature, either in crudes or after purification, were in the range normally used for the simultaneous saccharification and fermentation in bioethanol production. In addition, the enzymatic hydrolysis of different β-glucans by both enzymes was studied. In the assayed conditions, both enzymes hydrolysed carboxymethylcellulose, a typical substrate for endoglucanases, although EG2 was much more efficient. However, EG1 was also able to hydrolyse lichenan and laminarin. These findings suggest the potential interest of EG2 for specific hydrolysis of cellulose, present in plant cell walls, to produce bioethanol, while the more promiscuous enzyme EG1 could be used for production of glucooligosaccharides.     

The new clinical standard of integrated quadruple stress echocardiography with ABCD protocol

Background

The detection of regional wall motion abnormalities is the cornerstone of stress echocardiography. Today, stress echo shows increasing trends of utilization due to growing concerns for radiation risk, higher cost and stronger environmental impact of competing techniques. However, it has also limitations: underused ability to identify factors of clinical vulnerability outside coronary artery stenosis; operator-dependence; low positivity rate in contemporary populations; intermediate risk associated with a negative test; limited value of wall motion beyond coronary artery disease. Nevertheless, stress echo has potential to adapt to a changing environment and overcome its current limitations.

Integrated-quadruple stress-echo

Four parameters now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-stress echo. They are: 1- regional wall motion abnormalities; 2-B-lines measured by lung ultrasound; 3-left ventricular contractile reserve assessed as the stress/rest ratio of force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D); 4- coronary flow velocity reserve on left anterior descending coronary artery (with color-Doppler guided pulsed wave Doppler). IQ-Stress echo allows a synoptic functional assessment of epicardial coronary artery stenosis (wall motion), lung water (B-lines), myocardial function (left ventricular contractile reserve) and coronary small vessels (coronary flow velocity reserve in mid or distal left anterior descending artery). In “ABCD” protocol, A stands for Asynergy (ischemic vs non-ischemic heart); B for B-lines (wet vs dry lung); C for Contractile reserve (weak vs strong heart); D for Doppler flowmetry (warm vs cold heart, since the hyperemic blood flow increases the local temperature of the myocardium). From the technical (acquisition/analysis) viewpoint and required training, B-lines are the kindergarten, left ventricular contractile reserve the primary (for acquisition) and secondary (for analysis) school, wall motion the university, and coronary flow velocity reserve the PhD program of stress echo.

Conclusion

Stress echo is changing. As an old landline telephone with only one function, yesterday stress echo used one sign (regional wall motion abnormalities) for one patient with coronary artery disease. As a versatile smart-phone with multiple applications, stress echo today uses many signs for different pathophysiological and clinical targets. Large scale effectiveness studies are now in progress in the Stress Echo2020 project with the omnivorous “ABCD” protocol.

     

Silver/silver chloride nanoparticles inhibit the proliferation of human glioblastoma cells

Glioblastomas (GBM) are aggressive brain tumors with very poor prognosis. While silver nanoparticles represent a potential new strategy for anticancer therapy, the silver/silver chloride nanoparticles (Ag/AgCl-NPs) have microbicidal activity, but had not been tested against tumor cells. Here, we analyzed the effect of biogenically produced Ag/AgCl-NPs (from yeast cultures) on the proliferation of GBM02 glioblastoma cells (and of human astrocytes) by automated, image-based high-content analysis (HCA). We compared the effect of 0.1–5.0 µg mL^?1 Ag/AgCl-NPs with that of 9.7–48.5 µg mL^?1 temozolomide (TMZ, chemotherapy drug currently used to treat glioblastomas), alone or in combination. At higher concentrations, Ag/AgCl-NPs inhibited GBM02 proliferation more effectively than TMZ (up to 82 and 62% inhibition, respectively), while the opposite occurred at lower concentrations (up to 23 and 53% inhibition, for Ag/AgCl-NPs and TMZ, respectively). The combined treatment (Ag/AgCl-NPs?+?TMZ) inhibited GBM02 proliferation by 54–83%. Ag/AgCl-NPs had a reduced effect on astrocyte proliferation compared with TMZ, and Ag/AgCl-NPs?+?TMZ inhibited astrocyte proliferation by 5–42%. The growth rate and population doubling time analyses confirmed that treatment with Ag/AgCl-NPs was more effective against GBM02 cells than TMZ (~?67-fold), and less aggressive to astrocytes, while Ag/AgCl-NP?+?TMZ treatment was no more effective against GBM02 cells than Ag/AgCl-NPs monotherapy. Taken together, our data indicate that 2.5 µg mL^?1 Ag/AgCl-NPs represents the safest dose tested here, which affects GBM02 proliferation, with limited effect on astrocytes. Our findings show that HCA is a useful approach to evaluate the antiproliferative effect of nanoparticles against tumor cells.     

Reduction of indole‐3‐acetic acid methyltransferase activity compensates for high‐temperature male sterility in Arabidopsis

High temperature is a general stress factor that causes a decrease in crop yield. It has been shown that auxin application reduces the male sterility caused by exposure to higher temperatures. However, widespread application of a hormone with vast effects on plant physiology may be discouraged in many cases. Therefore, the generation of new plant varieties that locally enhance auxin in reproductive organs may represent an alternative strategy. We have explored the possibility of increasing indole‐3‐acetic acid (IAA) in ovaries by reducing IAA methyltransferase1 (IAMT1) activity in Arabidopsis thaliana. The iamt1 mutant showed increased auxin signalling in funiculi, which correlated with a higher growth rate of wild‐type pollen in contact with mutant ovaries and premature ovule fertilization. While the production of seeds per fruit was similar in the wild type and the mutant at 20 °C, exposure to 29 °C caused a more severe decrease in fertility in the wild type than in the mutant. Loss of IAMT1 activity was also associated with the production of more nodes after flowering and higher tolerance of the shoot apical meristem to higher temperatures. As a consequence, the productivity of the iamt1 mutant under higher temperatures was more than double of that of the wild type, with almost no apparent trade‐off.     

New ribosome-inactivating proteins with polynucleotide:adenosine glycosidase and antiviral activities from Basella rubra L. and Bougainvillea spectabilis Willd.

New single-chain (type 1) ribosome-inactivating proteins (RIPs) were isolated from the seeds of Basella rubra L. (two proteins) and from the leaves of Bougainvillea spectabilis Willd. (one protein). These RIPs inhibit protein synthesis both in a cell-free system, with an IC₅₀ (concentration causing 50% inhibition) in the 10⁻¹⁰ M range, and by various cell lines, with IC₅₀s in the 10⁻⁸–10⁻⁶ M range. All three RIPs released adenine not only from rat liver ribosomes but also from Escherichia coli rRNA, polyadenylic acid, herring sperm DNA, and artichoke mottled crinkle virus (AMCV) genomic RNA, thus being polynucleotide:adenosine glycosidases. The proteins from Basella rubra had toxicity to mice similar to that of most type 1 RIPs (Barbieri et al., 1993, Biochim Biophys Acta 1154: 237–282) with an LD₅₀ (concentration that is 50% lethal) ≤ 8 mg · kg⁻¹ body weight, whilst the RIP from Bougainvillea spectabilis had an LD₅₀ >32 mg · kg⁻¹. The N-terminal sequence of the two RIPs from Basella rubra had 80–93% identity, whereas it differed from the sequence of the RIP from Bougainvillea spectabilis. When tested with antibodies against various RIPs, the RIPs from Basella gave some cross-reactivity with sera against dianthin 32, and weak cross-reactivity with momordin I and momorcochin-S, whilst the RIP from Bougainvillea did not cross-react with any antiserum tested. An RIP from Basella rubra and one from Bougainvillea spectabilis were tested for antiviral activity, and both inhibited infection of Nicotiana benthamiana by AMCV. Received: 5 March 1997 / Accepted: 27 May 1997     

Activation of the IGF1 system characterizes cholangiocyte survival during progression of primary biliary cirrhosis.

We evaluated the IGF1 system in cholangiocytes of primay biliary cirrhosis (PBC) patients and investigated the relationships with apoptosis. Biopsies of PBC patients (n=32) and normal subjects (n=5) were investigated by immunohistochemistry for expression in cholangiocytes of IGF1, IGF1-R, pAKT, terminal deoxynucleotide transferase end labeling (TUNEL), Bax (proapoptotic protein), and Bcl2 (antiapoptotic protein). Whereas normal cholangiocytes were almost negative, cholangiocytes of PBC patients showed strong IHC staining for IGF1, IGF1-R, and pAKT, which increases from stage I to stage IV, where >70% of cholangiocytes were positive. Bax/Bcl2 ratio reached the highest value (4.6) in PBC stage III when apoptosis is maximal (24% TUNEL positivity), whereas it declines in stage IV (1.4) when only 7.8% cholangiocytes were TUNEL positive. In PBC stages III and IV, expression of IGF1, IGF1-R, and pAKT in cholangiocytes was directly correlated with the antiapoptotic Bcl2 and inversely correlated with proapoptotic Bax, Bax/Bcl2 ratio, and TUNEL positivity. In conclusion, cholangiocytes of PBC patients showed a marked increase in IGF1, IGF1-R, and pAKT expression involving most cholangiocytes surviving in the terminal ductopenic stage. This was associated and correlated with a balance of pro- and antiapoptotic proteins favoring survival rather than apoptosis, suggesting a major role of IGF1 system in promoting cholangiocyte survival.     

Estimation of genetic purging under competitive conditions

Inbreeding depression for fitness traits is a key issue in evolutionary biology and conservation genetics. The magnitude of inbreeding depression, though, may critically depend on the efficiency of genetic purging, the elimination or recessive deleterious mutations by natural selection after they are exposed by inbreeding. However, the detection and quantification of genetic purging for nonlethal mutations is a rather difficult task. Here, we present two comprehensive sets of experiments with Drosophila aimed at detecting genetic purging in competitive conditions and quantifying its magnitude. We obtain, for the first time in competitive conditions, an estimate for the predictive parameter, the purging coefficient (d), that quantifies the magnitude of genetic purging, either against overall inbreeding depression (d ≈ 0.3), or against the component ascribed to nonlethal alleles (d_NL ≈ 0.2). We find that competitive fitness declines at a high rate when inbreeding increases in the absence of purging. However, in moderate size populations under competitive conditions, inbreeding depression need not be too dramatic in the medium to short term, as the efficiency of purging is also very high. Furthermore, we find that purging occurred under competitive conditions also reduced the inbreeding depression that is expressed in the absence of competition.