Effects of the surfactant tween 80 on enzymatic hydrolysis of newspaper

The effects of Tween 80 on the enzymatic hydrolysis of newspaper were tested. By monitoring sugar production it was found that the surfactant (0.1%) increased the rate and extent of cellulose saccharification. Consequently, the rate of enzyme usage in the hydrolysis reactor was improved by 33%. In addition, in the presence of surfactant the recovery of enzymes was higher. Analysis of the enzyme solution showed that with Tween 80 present larger fractions of enzyme remained in solution throughout hydrolysis. Thus, it appears that the surfactant hindered the immobilization of the enzymes on the substrates by reducing the strength of adsorption.     

The immunoglobulin-like protein Hibris functions as a dose-dependent regulator of myoblast fusion and is differentially controlled by Ras and Notch signaling.

Hibris (Hbs) is a transmembrane immunoglobulin-like protein that shows extensive homology to Drosophila Sticks and stones (Sns) and human kidney protein Nephrin. Hbs is expressed in embryonic visceral, somatic and pharyngeal mesoderm among other tissues. In the somatic mesoderm, Hbs is restricted to fusion competent myoblasts and is regulated by Notch and Ras signaling pathways. Embryos that lack or overexpress hbs show a partial block of myoblast fusion, followed by abnormal muscle morphogenesis. Abnormalities in visceral mesoderm are also observed. In vivo mapping of functional domains suggests that the intracellular domain mediates Hbs activity. Hbs and its paralog, Sns, co-localize at the cell membrane of fusion-competent myoblasts. The two proteins act antagonistically: loss of sns dominantly suppresses the hbs myoblast fusion and visceral mesoderm phenotypes, and enhances Hbs overexpression phenotypes. Data from a P-homed enhancer reporter into hbs and co-localization studies with Sns suggest that hbs is not continuously expressed in all fusion-competent myoblasts during the fusion process. We propose that the temporal pattern of hbs expression within fusion-competent myoblasts may reflect previously undescribed functional differences within this myoblast population.     

Migration of zebrafish primordial germ cells: a role for myosin contraction and cytoplasmic flow

The molecular and cellular mechanisms governing cell motility and directed migration in response to the chemokine SDF-1 are largely unknown. Here, we demonstrate that zebrafish primordial germ cells whose migration is guided by SDF-1 generate bleb-like protrusions that are powered by cytoplasmic flow. Protrusions are formed at sites of higher levels of free calcium where activation of myosin contraction occurs. Separation of the acto-myosin cortex from the plasma membrane at these sites is followed by a flow of cytoplasm into the forming bleb. We propose that polarized activation of the receptor CXCR4 leads to a rise in free calcium that in turn activates myosin contraction in the part of the cell responding to higher levels of the ligand SDF-1. The biased formation of new protrusions in a particular region of the cell in response to SDF-1 defines the leading edge and the direction of cell migration.     

Cognitive and emotional alterations are related to hippocampal inflammation in a mouse model of metabolic syndrome

Converging clinical data suggest that peripheral inflammation is likely involved in the pathogenesis of the neuropsychiatric symptoms associated with metabolic syndrome (MetS). However, the question arises as to whether the increased prevalence of behavioral alterations in MetS is also associated with central inflammation, i.e. cytokine activation, in brain areas particularly involved in controlling behavior. To answer this question, we measured in a mouse model of MetS, namely the diabetic and obese db/db mice, and in their healthy db/+ littermates emotional behaviors and memory performances, as well as plasma levels and brain expression (hippocampus; hypothalamus) of inflammatory cytokines. Our results shows that db/db mice displayed increased anxiety-like behaviors in the open-field and the elevated plus-maze (i.e. reduced percent of time spent in anxiogenic areas of each device), but not depressive-like behaviors as assessed by immobility time in the forced swim and tail suspension tests. Moreover, db/db mice displayed impaired spatial recognition memory (hippocampus-dependent task), but unaltered object recognition memory (hippocampus-independent task). In agreement with the well-established role of the hippocampus in anxiety-like behavior and spatial memory, behavioral alterations of db/db mice were associated with increased inflammatory cytokines (interleukin-1β, tumor necrosis factor-α and interleukin-6) and reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus but not the hypothalamus. These results strongly point to interactions between cytokines and central processes involving the hippocampus as important contributing factor to the behavioral alterations of db/db mice. These findings may prove valuable for introducing novel approaches to treat neuropsychiatric complications associated with MetS.     

The RADAR Study: Week 48 Safety and Efficacy of RAltegravir Combined with Boosted DARunavir Compared to Tenofovir/Emtricitabine Combined with Boosted Darunavir in Antiretroviral-Naive Patients. Impact on Bone Health

Background

NRTI-sparing regimens may avoid long-term mitochondrial, bone and renal toxicities and maintain viral suppression.

Methods

In the RADAR study, 85 antiretroviral-naïve HIV-infected patients were randomized to receive either raltegravir (RAL) (n = 42) or tenofovir/emtricitabine (TDF/FTC) (n = 43), each with ritonavir-boosted darunavir (DRV/r). Virologic efficacy was assessed at weeks 24 and 48. Bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry (DXA) scan at baseline and week 48, and bone turnover markers (BTM) assessed at weeks 0, 16 and 48.

Results

Using an intention-to-treat analysis, 62.5% of RAL subjects and 83.7% of TDF/FTC subjects were responders (VL<48 copies/mL) at week 48 (p = 0.045; chi-square test). The proportions of patients achieving VL<200 copies/mL were similar: 72.5% and 86.0% (p = 0.175). Premature treatment discontinuation was the main cause for failure. No treatment-emergent resistance was observed. Changes from baseline in RAL vs. TDF/FTC for CD4⁺ (+199 vs. +216 cells/µL, p = 0.63), total cholesterol/HDL (−0.25 vs. −0.71 mg/dL (p = 0.270), and eGFR (−4.4 vs. −7.9 ml/min, p = 0.44) were comparable between groups. Changes in subtotal BMD to week 48 were: +9.2 with RAL vs. −7 g/cm² with TDF/FTC (p = 0.002). Mean CTX changes were +0.04 vs. +0.24 ng/mL (p = 0.001), and mean P1NP changes were +3.59 vs. +30.09 ng/mL (p = 0.023). BTM changes at week 16 predicted change in BMD by week 48 (R = −0.394, p = 0.003 for CTX; and R = −0.477, p<0.001 for P1NP).

Conclusion

The NRTI-sparing regimen RAL+DRV/r did not achieve similar week 48 virologic efficacy compared with TDF/FTC+DRV/r, but was better with regard to markers of bone health.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT 00677300","term_id":"NCT00677300"}}NCT 00677300     

Oriented cell division in vertebrate embryogenesis

Tissue morphogenesis depends on the spatial arrangement of cells during development. A number of mechanisms have been described to contribute to the final shape of a tissue or organ, ranging from cell intercalation to the response of cells to chemotactic cues. One such mechanism is oriented cell division. Oriented cell division is determined by the position of the mitotic spindle. Indeed, there is increasing evidence implicating spindle misorientation in tissue and organ misshaping, which underlies disease conditions such as tumorigenesis or polycystic kidneys. Here we review recent studies addressing how the direction of tissue growth is determined by the orientation of cell division and how both extrinsic and intrinsic cues control the position of the mitotic spindle.