Effects of retinoic acid on the development of liver fibrosis produced by carbon tetrachloride in mice

The role of retinoic acid (RA) in liver fibrogenesis was previously studied in cultured hepatic stellate cells (HSCs). RA suppresses the expression of alpha2(I) collagen by means of the activities of specific nuclear receptors RARalpha, RXRbeta and their coregulators. In this study, the effects of RA in fibrogenesis were examined in carbon tetrachloride (CCl4) induced liver fibrosis in mice. Mice were treated with CCl4 or RA and CCl4, along side control groups, for 12weeks. RA reduced the amount of histologically detectable fibrosis produced by CCl4. This was accompanied by a attenuation of the CCl4 induced increase in alpha2(I) collagen mRNA and a lower (2-fold versus 3-fold) increase in liver hydroxyproline. Furthermore, RA reduced the levels of 3-nitrotyrosine (3-NT) protein adducts and thiobarbituric acid (TBA) reactive substance (TBARS) in the liver, which are formed as results of oxidative stress induced by CCl4 treatment. These in vivo findings support our previous in vitro studies in cultured HSC of the inhibitory effect of RA on type I collagen expression. The data also provide evidence that RA reduces CCl4 induced oxidative stress in liver, suggesting that the anti-fibrotic role of RA is not limited to the inhibition of type I collagen expression.     

Optimization of citric acid production by Aspergillus niger using two downgraded Algerian date varieties

In the present work, the GHARS and the MECH DEGLA downgraded date varieties were used in a fermentation medium in order to produce citric acid by the Aspergillus niger. The biochemical characteristics of the dates were investigated, along with the chemical and physical characteristics of the solutions of both samples. The analyzed parameters included the moisture and sugar content, the ash residual, the pH values, and the electrical conductivity. The effect of the following fermentation parameters was studied: initial pH, temperature, incubation period, and methanol. For the GHARS and MECH DEGLA date varieties respectively, the ash residual measured at 1.90% and 2.47%. For each date variety, the moisture and total sugars were measured at 11.59% and 85%, for the GHARS, and 12.82% and 80.47% for the MECH DEGLA. Citric acid production using either of the two varieties of dates showed a high yield in a short time.The obtained results showed that the highest production of citric acid by both medium of dates was achieved at the initial pH value of 3.0, temperature 30 °C, and an incubation period of 8 days. Also, the maximum amount of citric acid was produced when both mediums contained 4% of methanol. Both varieties of dates showed a good yield for the citric acid and can be used as a culture medium since they are economic and ensure good growth for the Aspergillus niger.     

Divergence in style length and pollen size leads to a postmating‐prezygotic reproductive barrier among populations of Silene latifolia

A central tenet of speciation research is the need to identify reproductive isolating barriers. One approach to this line of research is to identify the phenotypes that lead to reproductive isolation. Several studies on flowering plants have shown that differences in style length contribute to reproductive isolation between species, leading us to consider whether style length could act as a reproductive barrier among populations of a single species. This could occur if style length varied sufficiently and pollen size covaried with style length. Populations of Silene latifolia exhibit variation in flower size, including style length, that is negatively correlated with annual precipitation. We show that this divergence in style length has a genetic basis and acts as a reproductive barrier: males from small‐flowered populations produced relatively small pollen grains that were poor at fertilizing ovules when crossed to females from large‐flowered populations, leading to a significant reduction in seed production. Manipulating the distance pollen tubes had to travel revealed that this failure was purely mechanical and not the result of other incompatibilities. These results show that style length acts as a postmating‐prezygotic reproductive barrier and indicate a potential link between ecotypic differentiation and reproductive isolation within a species.     

Facial correlates of sociosexuality

Previous studies have documented variation in sexual behaviour between individuals leading to the notion of ‘restricted’ individuals (i.e., people who prefer long-term relationships) and ‘unrestricted’ individuals (i.e., people who are open to short-term relationships). This distinction is often referred to as sociosexual orientation. Observers have been previously found to distinguish sociosexuality from video footage of individuals, although the specific cues used have not been identified. Here we assessed the ability of observers to judge sexual strategy based specifically on cues in both facial composites and real faces. We also assessed how observers' perceptions of the masculinity/femininity and attractiveness of faces relate to the sociosexual orientation of the pictured individuals. Observers were generally able to identify restricted vs. unrestricted individuals from cues in both composites and real faces. Unrestricted sociosexuality was generally associated with greater attractiveness in female composites and real female faces and greater masculinity in male composites. Although male observers did not generally associate sociosexuality with male attractiveness, female observers generally preferred more restricted males' faces (i.e., those with relatively strong preferences for long-term relationships). Collectively, our results support previous findings that androgenisation in men is related to less restricted sexual behaviour and suggest that women are averse to unrestricted men.     

Fyn kinase activity is required for normal organization and functional polarity of the mouse oocyte cortex

The objective of the present study was to determine whether Fyn kinase participated in signaling events during sperm–egg interactions, sperm incorporation, and meiosis II. The functional requirement of Fyn kinase activity in these events was tested through the use of the protein kinase inhibitor SKI‐606 (Bosutinib) and by analysis of Fyn‐null oocytes. Suppression of Fyn kinase signaling prior to fertilization caused disruption of the functional polarity of the oocyte with the result that sperm were able to fuse with the oocyte in the immediate vicinity of the meiotic spindle, a region that normally does not allow sperm fusion. The loss of functional polarity was accompanied by disruption of the microvilli and cortical granule‐free zone that normally overlie the meiotic spindle. Changes in the distribution of cortical granules and filamentous actin provided further evidence of disorganization of the oocyte cortex. Rho B, a molecular marker for oocyte polarity, was unaffected by suppression of Fyn activity; however, the polarized association of Par‐3 with the cortex overlying the meiotic spindle was completely disrupted. The defects in oocyte polarity in Fyn‐null oocytes correlated with a failure of the MII chromosomes to maintain a position close to the oocyte cortex which seemed to underlie the above defects in oocyte polarity. This was associated with a delay in completion of meiosis II. Pronuclei, however, eventually formed and subsequent mitotic cleavages and blastocyst formation occurred normally. Mol. Reprod. Dev. 76: 819–831, 2009. © 2009 Wiley‐Liss, Inc.     

High affinity glycosaminoglycan and autoantigen interaction explains joint specificity in a mouse model of rheumatoid arthritis

In the K/BxN mouse model of rheumatoid arthritis, autoantibodies specific for glucose-6-phosphate isomerase (GPI) can transfer joint-specific inflammation to most strains of normal mice. Binding of GPI and autoantibody to the joint surface is a prerequisite for joint-specific inflammation. However, how GPI localizes to the joint remains unclear. We show that glycosaminoglycans (GAGs) are the high affinity (83 nm) joint receptors for GPI. The binding affinity and structural differences between mouse paw/ankle GAGs and elbows/knee GAGs correlated with the distal to proximal disease severity in these joints. We found that cartilage surface GPI binding was greatly reduced by either chondroitinase ABC or beta-glucuronidase treatment. We also identified several inhibitors that inhibit both GPI/GAG interaction and GPI enzymatic activities, which suggests that the GPI GAG-binding domain overlaps with the active site of GPI enzyme. Our studies raise the possibility that GAGs are the receptors for other autoantigens involved in joint-specific inflammatory responses.     

A novel osteoclast precursor cell line, 4B12, recapitulates the features of primary osteoclast differentiation and function: Enhanced transfection efficiency before and after differentiation

Osteoclasts are bone‐resorbing multinucleated cells differentiated from monocyte/macrophage lineage precursors. A novel osteoclast precursor cell line, 4B12 was established from Mac‐1⁺c‐Fms⁺RANK⁺ cells from calvaria of 14‐day‐old mouse embryos using immunofluorescence and cell‐sorting methods. Like M‐CSF‐dependent bone marrow macrophages (M‐BMMs), M‐CSF is required for 4B12 cells to differentiate into TRAP‐positive multinucleated cells [TRAP(+) MNCs] in the presence of RANKL. Bone‐resorbing osteoclasts differentiated from 4B12 cells on dentine slices possess both a clear zone and ruffled borders and express osteoclast‐specific genes. Bone‐resorbing activity, but not TRAP, was enhanced in the presence of IL‐1α. The number of TRAP(+) MNCs and the number of pits formed from 4B12 cells on dentine slices was fourfold higher than that from M‐BMMs. 4B12 cells were identified as macrophages with Mac‐1 and F4/80, yet lost these markers upon differentiation into osteoclasts as determined by confocal laser scanning microscopy. The 4B12 cells do not have the potential to differentiate into dendritic cells indicating commitment to the osteoclast lineage. 4B12 cells are readily transfectable with siRNA transfection before and after differentiation. These data show that 4B12 cells faithfully replicate the properties of primary cells and are a useful and powerful model for analyzing the molecular and cellular regulatory mechanisms of osteoclastogenesis and osteoclast function. J. Cell. Physiol. 221: 40–53, 2009. © 2009 Wiley‐Liss, Inc