Dominant Mutations in GRHL3 Cause Van der Woude Syndrome and Disrupt Oral Periderm Development

Mutations in interferon regulatory factor 6 (IRF6) account for ∼70% of cases of Van der Woude syndrome (VWS), the most common syndromic form of cleft lip and palate. In 8 of 45 VWS-affected families lacking a mutation in IRF6, we found coding mutations in grainyhead-like 3 (GRHL3). According to a zebrafish-based assay, the disease-associated GRHL3 mutations abrogated periderm development and were consistent with a dominant-negative effect, in contrast to haploinsufficiency seen in most VWS cases caused by IRF6 mutations. In mouse, all embryos lacking Grhl3 exhibited abnormal oral periderm and 17% developed a cleft palate. Analysis of the oral phenotype of double heterozygote (Irf6^+/−;Grhl3^+/−) murine embryos failed to detect epistasis between the two genes, suggesting that they function in separate but convergent pathways during palatogenesis. Taken together, our data demonstrated that mutations in two genes, IRF6 and GRHL3, can lead to nearly identical phenotypes of orofacial cleft. They supported the hypotheses that both genes are essential for the presence of a functional oral periderm and that failure of this process contributes to VWS.     

Muscle performance during maximal isometric and dynamic contractions is influenced by the stiffness of the tendinous structures.

Contractile force is transmitted to the skeleton through tendons and aponeuroses, and, although it is appreciated that the mechanocharacteristics of these tissues play an important role for movement performance with respect to energy storage, the association between tendon mechanical properties and the contractile muscle output during high-force movement tasks remains elusive. The purpose of the study was to investigate the relation between the mechanical properties of the connective tissue and muscle performance in maximal isometric and dynamic muscle actions. Sixteen trained men participated in the study. The mechanical properties of the vastus lateralis tendon-aponeurosis complex were assessed by ultrasonography. Maximal isometric knee extensor force and rate of torque development (RTD) were determined. Dynamic performance was assessed by maximal squat jumps and countermovement jumps on a force plate. From the vertical ground reaction force, maximal jump height, jump power, and force-/velocity-related determinants of jump performance were obtained. RTD was positively related to the stiffness of the tendinous structures (r = 0.55, P < 0.05), indicating that tendon mechanical properties may account for up to 30% of the variance in RTD. A correlation was observed between stiffness and maximal jump height in squat jumps and countermovement jumps (r = 0.64, P < 0.05 and r = 0.55, P < 0.05). Power, force, and velocity parameters obtained during the jumps were significantly correlated to tendon stiffness. These data indicate that muscle output in high-force isometric and dynamic muscle actions is positively related to the stiffness of the tendinous structures, possibly by means of a more effective force transmission from the contractile elements to the bone.     

Quantitative comparison of the mycolic and fatty acid compositions of Mycobacterium leprae and Mycobacterium gordonae

The mycolic and fatty acids of three samples each of Mycobacterium leprae and Mycobacterium gordonae were compared. Acids released by whole-organism alkaline hydrolysis were converted to 4-nitrobenzyl esters and mycolic acids were further derivatized to t-butyldimethylsilyl ethers. Thin-layer chromatography of the derivatized long-chain extracts showed that all three M. leprae preparations contained so-called alpha-mycolates and ketomycolates but that the M. gordonae samples had a methoxymycolate in addition to the above types. Silica gel normal-phase high-performance liquid chromatography of the total mycolic acid derivatives confirmed the lack of detectable amounts of methoxymycolates in M. leprae and reverse-phase chromatography of the individual mycolate types demonstrated the homogeneity of the chain lengths of the mycolic acids in each species. Non-hydroxylated fatty acid 4-nitrobenzyl esters were transformed to methyl esters and examined by gas chromatography. Tuberculostearic (10-methyloctadecanoic) acid was a major component of the lipids of all three M. leprae preparations but it was absent in one M. gordonae strain and a very minor component in the other representatives of this latter species. On the basis of fatty and mycolic acid compositions, therefore, a previously suggested close relationship between M. leprae and M. gordonae was not supported.     

Wild-type Leishmania donovani promastigotes block maturation, increase integrin expression and inhibit detachment of human monocyte-derived dendritic cells – the influence of phosphoglycans

The protective immune response against the parasite, including the role of dendritic cells (DC) in the course of infection, plays a fundamental role. This study shows that wild-type (WT) Leishmania promastigotes and specifically the phosphoglycans family of virulence-associated antigens inhibit human monocyte-derived dendritic cells (MoDC) maturation and detachment to distinct surfaces. Immature phagocytosis of Leishmania donovani promastigotes by immature MoDC results in the increased expression of CD11b and CD51, and inhibition of cell detachment to distinct surfaces, which was dependent on the presence of phosphoglycans. These findings demonstrate that phosphoglycans of WT L. donovani might also inhibit human DC migration to lymphoid organs.     

An <Emphasis Type=Italic>in vivo</Emphasis> reporter of BMP signaling in organogenesis reveals targets in the developing kidney

Background  

Bone morphogenetic proteins (BMPs) regulate essential processes during organogenesis, and a functional understanding of these secreted proteins depends on identification of their target cells. In this study, we generate a transgenic reporter for organogenesis studies that we use to define BMP pathway activation in the developing kidney.     

Characterization of cells in the developing human liver

Human hepatic progenitor cells (HPCs) have been shown to co-express the hematopoietic stem cell (HSC) markers, CD117 and CD34. These cells differentiate not only into hepatocytes and cholangiocytes but also into pancreatic ductal and acinar cells under certain conditions. The fetal liver (FL) is rich in precursor/stem cells; however, little is known about (i) the markers expressed by liver cells during fetal development and (ii) whether an equivalent to the adult liver stem-like progenitors exists in the FL. Here, (i) FL tissue obtained from human 5-18-week-old fetuses were evaluated by means of flow cytometry, immunocyto-, and histochemistry for the emergence of cells expressing and co-expressing known hematopoietic, hepatic, and pancreatic cell markers, and (ii) isolated putative HPCs were phenotypically and molecularly characterized. We report that (i) red blood and endothelial cell precursors were most abundant in early gestation. Cells expressing HSC and pancreatic markers were found in the first trimester, while cells expressing hepatic markers appeared in the second trimester. Very few committed cells were present in FLs obtained early in the first trimester. In addition, cells expressing pancreatic markers co-expressed the HSC marker CD117. (ii) Isolated CD117+/CD34+/CD90- cells in vitro expressed both the genes and proteins for the hepatic markers such as albumin, alpha feto protein (AFP), alpha1-antitrypsin, and cytokeratin 19 (CK19). Our study suggests that hepatoblast and ductal plate/bile duct development mainly occurs during the second trimester. FLs in gestation weeks 5-9 had the highest numbers of precursor cells and the least committed cells. Cells that differentiate into Alb+ or CK19+ can be isolated from early FLs and may be appropriate progenitors for establishing novel systems to investigate basic mechanisms for cell therapy.     

A Program for Monitoring Biological Diversity in the Amazon: An Alternative Perspective to Threat-based Monitoring

Ferraz et al . (2008) indicated the need for planning in biological monitoring in the Amazon, and reviewed what they considered recent progress. The problems and solutions they discuss are well known, and it is unlikely that many biologists would disagree with most of them. However, the authors do not indicate that most of these issues are already being addressed in practice in the Amazon, especially by the Programa de Pesquisas em Biodiversidade (PPBio) of the Brazilian Ministry of Science and Technology. The only major issue about which we do not agree with Ferraz et al . (2008) relates to the design of monitoring programs. The authors recommended tailoring experimental designs to specific threats, which will result in a multitude of idiosyncratic designs and incompatible data sets. We suggest that generic broad-scale designs will allow us to answer more questions with greater confidence, because the investment in each location provides information about regional and global questions. Although specific designs may be more effective in some cases, there are insufficient resources available to install different research infrastructure for every possible threat.     

Decreased prevalence of Plasmodium falciparum resistance markers to amodiaquine despite its wide scale use as ACT partner drug in Zanzibar

ABSTRACT: BACKGROUND: Zanzibar has recently undergone a rapid decline in Plasmodium falciparum transmission following combined malaria control interventions with artemisinin-based combination therapy (ACT) and integrated vector control. Artesunate-amodiaquine (ASAQ) was implemented as first-line treatment for uncomplicated P. falciparum malaria in Zanzibar in 2003. Resistance to amodiaquine has been associated with the single nucleotide polymorphism (SNP) alleles pfcrt 76T, pfmdr1 86Y, 184Y and 1246Y. An accumulation of these SNP alleles in the parasite population over time might threaten ASAQ efficacy. The aim of this study was to assess whether prolonged use of ASAQ as first-line anti-malarial treatment selects for P. falciparum SNPs associated with resistance to the ACT partner drug amodiaquine. METHODS: The individual as well as the combined SNP allele prevalence were compared in pretreatment blood samples from patients with uncomplicated P. falciparum malaria enrolled in clinical trials conducted just prior to the introduction of ASAQ in 2002-2003 (n = 208) and seven years after wide scale use of ASAQ in 2010 (n = 122). RESULTS: There was a statistically significant decrease of pfcrt 76T (96-63%), pfmdr1 86Y (75-52%), 184Y (83-72%), 1246Y (28-16%) and the most common haplotypes pfcrt/pfmdr1 TYYD (46-26%) and TYYY (17-8%), while an increase of pfcrt/pfmdr1 KNFD (0.4-14%) and KNYD (1-12%). CONCLUSIONS: This is the first observation of a decreased prevalence of pfcrt 76T, pfmdr1 86Y, 184Y and 1246Y in an African setting after several years of extensive ASAQ use as first-line treatment for uncomplicated malaria. This may support sustained efficacy of ASAQ on Zanzibar, although it was unexpected considering that all these SNPs have previously been associated with amodiaquine resistance. The underlying factors of these results are unclear. Genetic dilution by imported P. falciparum parasites from mainland Tanzania, a de-selection by artesunate per se and/or an associated fitness cost might represent contributing factors. More detailed studies on temporal trends of molecular markers associated with amodiaquine resistance are required to improve the understanding of this observation.     

Synthesis of selected aminodeoxy analogs of globotriosylceramide

Four aminodeoxy analogs of globotriosylceramide (6"-, 4"-, 2"-, and 6'-aminodeoxy) were synthesized by glycosylation of 3-O-benzoylated azidosphingosine with the corresponding aminodeoxy-globotriose trichloroacetimidate, followed by reduction of the azido group, N-acylation with 1-adamantaneacetic acid, and removal of the protecting groups.