Evaluation of phytochemical and antimicrobial properties of leaf extract of Tapinanthus sessilifolius (P. Beauv) van Tiegh

Leaf extracts of T. sessilifolius growing on five different host plants (Psidium guajava, Citrus lemon, Vernonia amygdalina, Persea americana and Jatropa curcas) were evaluated for antimicrobial activity of the plant. Powdered leaves of T. sessilifolius collected from each host plant was divided into two portions. One portion was used for aqueous infusion and the other portion was successively extracted with hexane, ethylacetate and methanol. Infusion of aqueous extract of powdered leaves did not show antimicrobial effect even at the concentration of 1000 and 2000 microg/ml on test microorganisms (Staph. aureus, E. coli, Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans). However in broth culture, methanolic and hexane extract had MIC range of 62.5-500 microg/ml and ethylacetate extract had 250-500 microg/ml. Phytochemical screening of leaf samples of T. sessilifolius collected from different host plants showed positive test for hydrolysable tannins, saponins, flavonoids, terpenes, cardiac glycoside, reducing sugars and proteins. LD50 concentration was found to be > 1.500 mg/kg for samples from P. guajava; 489.89 mg/kg for J. curcas and C. lemon; and 692 mg/kg for V. amydalina in mice.     

POC1A Truncation Mutation Causes a Ciliopathy in Humans Characterized by Primordial Dwarfism

Primordial dwarfism (PD) is a phenotype characterized by profound growth retardation that is prenatal in onset. Significant strides have been made in the last few years toward improved understanding of the molecular underpinning of the limited growth that characterizes the embryonic and postnatal development of PD individuals. These include impaired mitotic mechanics, abnormal IGF2 expression, perturbed DNA-damage response, defective spliceosomal machinery, and abnormal replication licensing. In three families affected by a distinct form of PD, we identified a founder truncating mutation in POC1A. This gene is one of two vertebrate paralogs of POC1, which encodes one of the most abundant proteins in the Chlamydomonas centriole proteome. Cells derived from the index individual have abnormal mitotic mechanics with multipolar spindles, in addition to clearly impaired ciliogenesis. siRNA knockdown of POC1A in fibroblast cells recapitulates this ciliogenesis defect. Our findings highlight a human ciliopathy syndrome caused by deficiency of a major centriolar protein.     

Recessive mutations in DOCK6, encoding the guanidine nucleotide exchange factor DOCK6, lead to abnormal actin cytoskeleton organization and Adams-Oliver syndrome

Adams-Oliver syndrome (AOS) is defined by the combination of aplasia cutis congenita (ACC) and terminal transverse limb defects (TTLD). It is usually inherited as an autosomal-dominant trait, but autosomal-recessive inheritance has also been documented. In an individual with autosomal-recessive AOS, we combined autozygome analysis with exome sequencing to identify a homozygous truncating mutation in dedicator of cytokinesis 6 gene (DOCK6) which encodes an atypical guanidine exchange factor (GEF) known to activate two members of the Rho GTPase family: Cdc42 and Rac1. Another homozygous truncating mutation was identified upon targeted sequencing of DOCK6 in an unrelated individual with AOS. Consistent with the established role of Cdc42 and Rac1 in the organization of the actin cytoskeleton, we demonstrate a cellular phenotype typical of a defective actin cytoskeleton in patient cells. These findings, combined with a Dock6 expression profile that is consistent with an AOS phenotype as well as the very recent demonstration of dominant mutations of ARHGAP31 in AOS, establish Cdc42 and Rac1 as key molecules in the pathogenesis of AOS and suggest that other regulators of these Rho GTPase proteins might be good candidates in the quest to define the genetic spectrum of this genetically heterogeneous condition.     

Microbial communities of urban stormwater sediments: the phylogenetic structure of bacterial communities varies with porosity

This study focuses on the distribution of bacterial and fungal communities within the microstructure of a multi-contaminated sedimentary layer resulting from urban stormwater infiltration. Fractionation was performed on the basis of differential porosity and aggregate grain size, resulting in five fractions: leachable fitting macroporosity, < 10, 10-160, 160-1000 μm fitting aggregates, > 1000 μm. Amounts of both bacterial and fungal biomasses are greater in the < 10 μm and leachable fractions. The aggregates contain numerous bacteria but very low amounts of fungal biomass. Single-strand conformational polymorphism molecular profiles highlighted the differences between bacterial and fungal communities of the leachable fraction and those of the aggregates. Random Sanger sequencing of ssu clones revealed that these differences were mainly because of the presence of Epsilonproteobacteria and Firmicutes in the leachable fractions, while the aggregates contained more Cyanobacteria. The Cyanobacteria phylotypes in the aggregates were dominated by the sequences related to Microcoleus vaginatus while the leachable fractions presented the sequences of chloroplastic origin. Therefore, more than 50% of the phylotypes observed were related to Proteobacteria while 40% were related to Cyanobacteria and Bacteroidetes. Preferential distribution of clades in almost all the phyla or classes detected was observed. This study provides insight into the identities of dominant members of the bacterial communities of urban sediments. Microcoleus vaginatus appeared to predominate in pioneer soils.     

Effect of the aqueous extract of African mistletoe,Tapinanthus sessilifolius (P. Beauv) van Tiegh leaf on gastrointestinal muscle activity

Effects of the aqueous extract of T. sessilifolius on the gastrointestinal muscle were investigated on smooth muscle preparations isolated from rabbit jejunum, guinea pig ileum and on gastrointestinal transit in mice. Elemental analysis of the extract was also carried out. The aqueous extract of T. sessilifolius evoked a concentration dependent contraction of the rabbit jejunum and guinea pig ileum. The contractions evoked by the extract were not attenuated either by atropine or mepyramine, but they were completely blocked by verapamil. The elemental analysis revealed the presence of Mg, Zn, Fe, Cu, and very high concentration of Ca. The intraperitoneal LD50 in mice was found to be 1500 mg/kg. The aqueous extract of T. sessilifoliius possesses active components that may be mediating the observed biological activity through calcium mobilization.     

Mutations in NALCN Cause an Autosomal-Recessive Syndrome with Severe Hypotonia,Speech Impairment,and Cognitive Delay

Sodium leak channel, nonselective (NALCN) is a voltage-independent and cation-nonselective channel that is mainly responsible for the leaky sodium transport across neuronal membranes and controls neuronal excitability. Although NALCN variants have been conflictingly reported to be in linkage disequilibrium with schizophrenia and bipolar disorder, to our knowledge, no mutations have been reported to date for any inherited disorders. Using linkage, SNP-based homozygosity mapping, targeted sequencing, and confirmatory exome sequencing, we identified two mutations, one missense and one nonsense, in NALCN in two unrelated families. The mutations cause an autosomal-recessive syndrome characterized by subtle facial dysmorphism, variable degrees of hypotonia, speech impairment, chronic constipation, and intellectual disability. Furthermore, one of the families pursued preimplantation genetic diagnosis on the basis of the results from this study, and the mother recently delivered healthy twins, a boy and a girl, with no symptoms of hypotonia, which was present in all the affected children at birth. Hence, the two families we describe here represent instances of loss of function in human NALCN.     

Mutations in DDX59 Implicate RNA Helicase in the Pathogenesis of Orofaciodigital Syndrome

Orofaciodigital syndrome (OFD) is a recognized clinical entity with core defining features in the mouth, face, and digits, in addition to various other features that have been proposed to define distinct subtypes. The three genes linked to OFD—OFD1, TMEM216, and TCTN3—play a role in ciliary biology, a finding consistent with the clinical overlap between OFD and other ciliopathies. Most autosomal-recessive cases of OFD, however, remain undefined genetically. In two multiplex consanguineous Arab families affected by OFD, we identified a tight linkage interval in chromosomal region 1q32.1. Exome sequencing revealed a different homozygous variant in DDX59 in each of the two families, and at least one of the two variants was accompanied by marked reduction in the level of DDX59. DDX59 encodes a relatively uncharacterized member of the DEAD-box-containing RNA helicase family of proteins, which are known to play a critical role in all aspects of RNA metabolism. We show that Ddx59 is highly enriched in its expression in the developing murine palate and limb buds. At the cellular level, we show that DDX59 is localized dynamically to the nucleus and the cytoplasm. Consistent with the absence of DDX59 representation in ciliome databases and our demonstration of its lack of ciliary localization, ciliogenesis appears to be intact in mutant fibroblasts but ciliary signaling appears to be impaired. Our data strongly implicate this RNA helicase family member in the pathogenesis of OFD, although the causal mechanism remains unclear.     

Petroselinum sativum protects HepG2 cells from cytotoxicity and oxidative stress induced by hydrogen peroxide

Molecular Biology Reports - A number of liver diseases are known to be caused by oxidative stress. Petroselinum sativum (P. sativum; parsley) is popular for its anti-inflammatory, antimicrobial,...