Assignment of the Human Homologue of the mTRiC-P5 Gene (TRICS) to Band 1q23 by Fluorescence in Situ Hybridization

The TCP1 ring complex (TRiC) is a molecular chaperone involved in actin and tubulin folding. Little is known about the components of this complex. The first component identified was TCP1, a protein coded by a gene in the t -complex locus on mouse chromosome 17. This locus is involved in several embryonic defects, male sterility, and the transmission ratio distortion. In humans, the t-complex genes map to chromosome 6. Other components of TRiC are thought to be TCP1-related proteins. Recently, a mouse cDNA coding for one of these proteins has been cloned and named mTRiC-P5. Here we report the cloning of a partial human cDNA clone, homologous to mTRiC-P5, and its chromosome localization by fluorescence in situ hybridization. The human TRiC-P5 gene (TRIC5) maps to human chromosome 1q23, a region known to be a preferential chromosomal breakpoint involved in leukemia. Therefore, even if TCP1 and TRiC-P5 are related proteins and are found in the same protein complex, they are not coded by syntenic genes in humans.     

Dissecting the impact of regional identity and the oncogenic role of human-specific NOTCH2NL in an hESC model of H3.3G34R-mutant glioma

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Osmotic shock improves <Emphasis Type="Italic">Tnt1</Emphasis> transposition frequency in <Emphasis Type="Italic">Medicago truncatula</Emphasis> cv Jemalong during in vitro regeneration

Insertion mutant collections are powerful tools for genetic studies in plants. Although large-scale insertional mutagenesis using T-DNA is not feasible in legumes, the Tnt1 tobacco retrotransposon can be used as a very efficient mutagen in the Medicago truncatula R108 genotype. In this article, we show that Tnt1 can also be exploited to create insertional mutants via transformation and/or regeneration in the reference cultivar Jemalong. Tnt1 insertional mutagenesis in Jemalong following Agrobacterium tumefaciens-mediated transformation was found to be very efficient, with an average of greater than 15 insertions/line. In contrast, regeneration using low-copy transgenic starter lines resulted in a highly variable rate of new Tnt1 insertions. With the goal of increasing the number of additional Tnt1 insertions during regeneration of starter lines, we have compared the insertion frequencies for a number of different regeneration protocols. In addition, we have been able to show that sucrose-mediated osmotic shock preceding regeneration significantly increases the transposition frequency. Under optimal conditions, 95% of the regenerated Jemalong plants possess new insertions.     

Resistance factors to intralesional immunotherapy with BCG or Corynebacterium parvum in rat tumors

Summary We have studied two variants of a single 3-MCA-induced transplantable tumor of rats, one of which is susceptible (S) to intratumoral (IT) injection of BCG, while the other is resistant (R). Some characteristics are identical in both tumors: growth curves, histology, and virulence, and there is cross immunity between (S) and (R).Other characteristics are different: (1) Living BCG administered IT persisted for 3 weeks in (S) but disappeared rapidly in (R). (2) After IT administration of BCG or Corynebacterium parvum, there was progressive lymphoid infiltration into (S) and cure without necrosis, while in (R) there was virtually no lymphoid cell infiltration at any time and no histological manifestation of regression. (3) Tumor tissue permeability was tested by the IV injection of ⁵¹Cr-labeled isologous red blood cells, ⁵¹Cr-labeled white blood cells, or ¹³¹I-labeled human albumin. These markers penetrated (S) to a greater extent than (R). Local injection of histamine and serotonin increased the penetration of the labeled protein into both tumors, but penetration of labeled cells only into (S). Passive local anaphylactic reactions augmented the penetration of markers in both tumors, but less in (R) than (S). (4) The immune response to sheep red blood cells was increased in rats bearing either (R) or (S). However, tuberculin skin tests in BCG-immunized rats were impaired more by (R) than by (S). Passive cutaneous anaphylactic reactions were more severely depressed by (R) than by (S).Resistance factors to IT immunotherapy are probably numerous, and may be linked to some differential characteristics of the variant (parisophanous) tumors.     

Ineffectiveness of Two Annual Legumes as Nurse Plants for Establishment of Artemisia californica in Coastal Sage Scrub

Annual legumes are often used as nurse plants for restoration projects, but two commonly used legume species were competitors at all densities with Artemisia californica (California sagebrush), a dominant shrub of southern California coastal sage scrub. Survival of Artemisia was not reduced by the lowest densities of the native Lupinus succulentus (arroyo lupine) at ratios of Artemisia to Lupinus of 1:1 or 1:3 or by the exotic Trifolium hirtum (rose clover) at the 1:1 density, but its survival was as low as 4% at the highest densities of Trifolium (1:16) and 1:32). Overall, Trifolium was more detrimental to survival of Artemisia, but the biomass of Artemisia was reduced by 90% or more in mixtures with both legumes even at the lowest densities of 1:1. The total soil nitrogen either did not change or decreased in two of the mixtures between planting and harvest dates, indicating that the legumes not only did not add nitrogen to the soil within one growing season but even depleted it in these two cases. Whereas Lupinus had greater aboveground bio-mass than Trifolium, it had a lower root density than Trifolium. The Artemisia root system was more shallow than either Trifolium or Lupinus, possibly explaining the poor growth of Artemisia in mixtures, The legumes were one to two orders of magnitude greater in aboveground biomass than Artemisia at the 1:1 ratio and therefore may be inappropriate choices as nurse plants. There is no evidence from this study that either of these legumes can act as nurse plants, even at the lowest ratio of one nurse plant to on shrub. Nurse plants are probably more important in harsher environments than in coastal sage scrub.     

Biphasic Activation of WNT Signaling Facilitates the Derivation of Midbrain Dopamine Neurons from hESCs for Translational Use

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Galactofuranose attenuates cellular adhesion of Aspergillus fumigatus

Galactofuranose (Gal f ) is a major molecule found in cell wall polysaccharides, secreted glycoproteins, membrane lipophosphoglycans and sphingolipids of Aspergillus fumigatus . The initial step in the Galf synthetic pathway is the re-arrangement of UDP-galactopyranose to UDP-Galf through the action of UDP-galactopyranose mutase. A mutant lacking the Af UGM1 gene encoding the UDP-galactopyranose mutase has been constructed. In the mutant, though there is a moderate reduction in the mycelial growth associated with an increased branching, it remains as pathogenic and as resistant to cell wall inhibitors and phagocytes as the wild-type parental strain. The major phenotype seen is a modification of the cell wall surface that results in an increase in adhesion of the mutants to different inert surfaces (glass and plastic) and epithelial respiratory cells. The adhesive phenotype is due to the unmasking of the mannan consecutive to the removal of galactofuran by the ugm1 mutation. Removal of the mannan layer from the mutant surface by a mannosidase treatment abolishes mycelial adhesion to surfaces.     

Desensitization to ANG II in guinea pig ileum depends on membrane repolarization: role of maxi-K+ channel

Desensitization of ANG II tonic contractile response of theguinea pig ileum is related to membrane repolarization determined byCa²⁺-activatedK⁺(maxi-K⁺) channelopening. ANG II-stimulated depolarized myocytes presented sustainedactivation of maxi-K⁺ channels,characterized by reduction from 415 to 12 ms of the closed timeconstant. ANG II desensitization was prevented by 100 nM iberiotoxin,being reversible within 30 min. Depolarization by KCl, higher than 4 mM, impaired desensitization, suggesting that the membrane potentialmust attain a threshold to counteract the repolarization induced bymaxi-K⁺ channel opening. Once thisvalue is attained, there is no time dependency because thedesensitization process was shut off by addition of KCl along the timecourse of the tonic response. In contrast, the sustained ACh toniccomponent was not altered by these maneuvers. We conclude thatdesensitization of the ANG II tonic component is foremost due to theopening of maxi-K⁺ channels,leading to membrane repolarization, thus closing the voltage-dependentCa²⁺ channels responsible for theCa²⁺ influx that sustains thetonic component in this muscle.

     

Genetic diversity of <Emphasis Type="Italic">Leishmania amazonensis</Emphasis>strains isolated in northeastern Brazil as revealed by DNA sequencing,PCR-based analyses and molecular karyotyping

Background  

Leishmania (Leishmania) amazonensis infection in man results in a clinical spectrum of disease manifestations ranging from cutaneous to mucosal or visceral involvement. In the present study, we have investigated the genetic variability of 18 L. amazonensis strains isolated in northeastern Brazil from patients with different clinical manifestations of leishmaniasis. Parasite DNA was analyzed by sequencing of the ITS flanking the 5.8 S subunit of the ribosomal RNA genes, by RAPD and SSR-PCR and by PFGE followed by hybridization with gene-specific probes.