Genetic disruption of mammalian endoplasmic reticulum-associated protein degradation: Human phenotypes and animal and cellular disease models

Endoplasmic reticulum-associated protein degradation (ERAD) is a stringent quality control mechanism through which misfolded, unassembled and some native proteins are targeted for degradation to maintain appropriate cellular and organelle homeostasis. Several in vitro and in vivo ERAD-related studies have provided mechanistic insights into ERAD pathway activation and its consequent events; however, a majority of these have investigated the effect of ERAD substrates and their consequent diseases affecting the degradation process. In this review, we present all reported human single-gene disorders caused by genetic variation in genes that encode ERAD components rather than their substrates. Additionally, after extensive literature survey, we present various genetically manipulated higher cellular and mammalian animal models that lack specific components involved in various stages of the ERAD pathway.     

Genetic relationships among actinomycetes that produce the immunosuppressant macrolides FK506, FK520/FK523 and rapamycin

Summary A polyphasic taxonomic study was undertaken to establish the genetic and phenotypic relationships among six actinomycetes that produce the immunosuppressant macrolides FK506, FK520/FK523 and rapamycin. Chemotaxonomic studies reveal that all have Type I cell walls. Gas chromatography (GC) of fatty acid methyl esters revealed patterns consistent for strains ofStreptomyces with 160 and 150anteiso predominating. Principal component analysis of GC data revealed distinct profiles for each culture. Reciprocal DNA homology studies atT _m -25 showed the rapamycin-producing strain and one FK506-producing strain to have 38–50% homology with the type strain ofStreptomyces hygroscopicus (ATCC 27438). The remaining strains exhibited 6–17% homology. To further explore the relationships among these strains all were probed for the presence of anO-methyltransferase gene specific to this biosynthetic pathway. Among the strains of interest, onlyStreptomyces hygroscopicus subsp.yakushimaensis, the patent strain for FK520/FK523, failed to hybridize with the probes.     

Tetanus toxin selectively impairs anti-tumoral but not anti-microbial macrophage-mediated effector functions

Abstract The present study was designed to establish the susceptibility of macrophage-mediated effector functions to tetanus toxin (TT). Using the murine macrophage cell line, GG2EE, generated in vitro by v- raf /v- myc oncogenes, we have previously provided evidence that TT selectively inhibits interferon gamma (IFN-γ), but not basal, lysozyme activity. Here we show that while neither phagocytic nor candidacidal activities are affected by TT treatment, antitumoral activity is significantly impaired after exposure to TT. This phenomenon, which is dose-dependent, is fully ascribed to the holotoxin, as heat inactivated TT, C or A-B fragments result ineffective. Furthermore, C but not A-B fragment competes with TT in abrogating its inhibitory effects. Overall, these data indicate that TT is not a broad-spectrum, down-regulating signal on macrophage-mediated functions, thus implying that its toxic action is exerted on specific molecular targets.     

First fossil evidence of samaras of Ventilago Gaertn. (Rhamnaceae) from India and its implications

The Ventilago Gaertn. (Rhamnaceae) is widely distributed in pantropical areas of Africa, Asia, and Australia. However, fossil records of this taxon are sparse, which limits understanding of the evolution and biogeographic history of the genus. In the present study, we report and describe two new fossil species of Ventilago, V. siwalika sp. nov. from the Miocene sediments of Himachal Pradesh, western Himalaya, and V. pliocenica sp. nov. from the Pliocene sediments of Jharkhand, eastern India based on single-winged samaras. Ventilago pliocenica is characterized by a prominent midvein, obtuse to sub-round apex with mucronate tip, longitudinal secondary veins extending the full length of the fruit, and reticulate nature of higher-order veins, the presence of equatorial rim, the hypanthium, and short pedicel. On the other hand, V. siwalika is characterized by a prominent midvein, obtuse to sub-round apex with mucronate tip, longitudinal secondary veins extending the full length of the fruit, and reticulate nature of higher-order veins. Our discovery represents the first unambiguous fossil record of single-winged samara of Ventilago from India and provides valuable insights into the evolution of this genus. In this paper, we also review its biogeographic history and add new information to understand its hypothetical migration route. Present and earlier records of Ventilago also suggest that this genus was a common forest element during Neogene (Miocene time) in Asia.     

Molecular cloning and complete nucleotide sequence of the repeated unit and flanking gene of the scallop Pecten maximus mitochondrial DNA: Putative replication origin features

In the bivalve mollusc Pecten maximus, the size of the mitochondrial DNA molecules ranges from 20 to 25.8 kbp. This variability is mainly correlated with the occurrence of a variable domain composed with two to five 1.6-kbp repeated units tandemly arrayed in the genome. DNA fragments spanning the 1,586-base-pair-long repeated element and the nearest flanking gene have been cloned and sequenced. This sequence was analyzed regarding its base composition and potential secondary structures. The repeated unit domain was positioned and oriented with regard to the known flanking gene. It ends 2 base pairs upstream relative to the beginning of the tRNA^gly gene. The peculiar properties of the repeated unit were compared with those of the 1,442-bp repeated element found in the mitochondrial genome of the deep sea scallop Placopecten magellanicus. This comparison provided evidence for the absence of nucleotide conservation, except for a small sequence engaged in a secondary structure, but argued for a strong pressure maintaining domains with specific nucleotide content. A possible role for the conserved sequence is discussed.Correspondence to: A. Rigaa     

Ataxia with Vitamin E Deficiency: Refinement of Genetic Localization and Analysis of Linkage Disequilibrium by Using New Markers in 14 Families

Ataxia with vitamin E deficiency (AVED) is an autosomal recessive disease characterized clinically by neurological symptoms with often striking resemblance to those of Friedreich ataxia. This disorder has been reported previously as familial isolated vitamin E deficiency. We have mapped recently the AVED locus to a 5-cM confidence interval on chromosome 8q by homozygosity mapping in six Mediterranean families. We have now analyzed six new and two previously described families and demonstrate genetic homogeneity despite important clinical variability and wide geographic origins. Analysis of nine new tightly linked microsatellite markers, including four characterized in this study, revealed a predominant but not unique mutation in northern African populations, where this condition is more frequent. Haplotype analysis but also classical recombinations allowed us to refine the AVED position to a 1-cM interval. A YAC contig over this interval was constructed from marker STSs and YAC fingerprint data, in order to facilitate the search of the AVED gene.     

Benthic foraminiferal fauna during the time of the Indian-Asian contact, in southern Balochistan, Pakistan

Cretaceous and early Paleocene benthic foraminifera were studied from one section along the western Gaj River, southern Balochistan, Pakistan, to reconstruct the paleoenvironment of the Tethys Sea during the Indian-Asian contact. We recognize three lithostratigraphic units in ascending order: the Mughal Kot Formation, the Pab Sandstone, and the Jamburo Group. Both the Maastrichtian Mughal Kot Formation, which consists of shale with grey marly limestone, and the Maastrichtian Pab Sandstone, which consists of quartzose sandstone, indicate an open ocean environment as they have diversified planktic and benthic foraminiferal assemblages. The Maastrichtian-Paleocene Jamburo Group, consisting of dark grey, calcareous shale and marlstone with some sulfide grains, is characterized by low diversities of benthic assemblages. The change to the lower diversities may be associated with the development of poor circulation of deeper water that was caused by narrowing of the Tethys Sea.The Trochammina spp. Assemblage from the Jamburo Group, which can be correlated with flysch-type agglutinated foraminiferal assemblages, has a low benthic species diversity, indicating an unfavorable condition for calcareous foraminifera because of the development of oxygen-depleted water. The absolute abundance of agglutinated specimens shows a remarkable change from low numbers in the Maastrichtian to high ones in the Paleocene. The benthic foraminiferal evidence supports the hypothesis that the collision of the Asian and Indian plates occurred near the end of the Cretaceous.     

Drug-induced circling preference in rats

Drugs of abuse, such as phencyclidine (PCP), methamphetamine (METH), and cocaine (COC) are known to affect several behaviors in rats, such as motor activity, stereotypy, and circling. In this study, we evaluated whether these drugs produce circling preferences in the presence or absence of unilateral 6-hydroxydopamine (6-OHDA)-induced lesions of the caudate nucleus. Adult male CD rats were lesioned with 10 μg 6-OHDA/site. Animals were dosed with PCP (15 mg/kg, ip), its congener, (+) MK-801 (0.15 mg/kg, ip), METH (2 mg/kg, ip), COC (60 mg/kg, ip), or apomorphine (0.2 mg/kg, ip). circling preference was recorded in control and lesioned rats for 2 h before animals were sacrificed to determine monoamine levels by HPLC/EC. In control animals, administration of these drugs produced 60–70% left circling. In, lesioned animals, these drugs produced 78–90% ipsilateral (toward the lesion) circling, except apomorphine, which produced 60–80% contralateral (away from the lesion) circling. Dopamine (DA) and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) concentrations significantly decreased ipsilaterally in lesioned caudate nucleus (CN) and substantia nigra (SN). However, no significant changes were observed in nucleus accumbens (NA) and olfactory tubercles (OT). These data demonstrate that drugs of abuse like PCP, its congener (+) MK-801, METH, and COC produce a greater preference to turn toward the left than the right, a finding similar to that found in human psychosis. Since 6-OHDA lesions enhanced the circling bias and depleted DA and its metabolites DOPAC and HVA, it also suggests that the dopaminergic system may be involved in the circling behavior.