A Bioinformatics Approach to Characterize Mammalian Selenoprotein T

The exact function and trafficking of selenoprotein T (SelT) are still unclear. This study was focused on using bioinformatics analysis as an approach to understanding the structure-function relationship of SelT and the trafficking of SelT between cellular compartments. Blast analysis revealed that SelT is present in mammals, birds, frogs, zebra fish, and green algae. Structural analyses revealed that SelT contains a CxxU motif in a thioredoxin-like fold, suggesting a redox function of SelT. Cysteine (Cys) residues were found in the place of selenocysteine in SelT Cys homologs in insects, roundworms, and plants. The SignalP program recognized signal peptides in both SelT and SelT Cys homologs. Mammalian SelT was predicted to contain an N-terminal signal peptide of 19 amino acid residues, which may be involved in targeting SelT to the endoplasmic reticulum. Finally, SelT may be localized in the plasma membrane in addition to its presence in the Golgi apparatus and the endoplasmic reticulum.     

Colocalization of MCT1, CD147, and LDH in mitochondrial inner membrane of L6 muscle cells: evidence of a mitochondrial lactate oxidation complex

Results of previous studies suggested a role of mitochondria in intracellular and cell-cell lactate shuttles. Therefore, by using a rat-derived L6 skeletal muscle cell line and confocal laser-scanning microscopy (CLSM), we examined the cellular locations of mitochondria, lactate dehydrogenase (LDH), the lactate-pyruvate transporter MCT1, and CD147, a purported chaperone protein for MCT1. CLSM showed that LDH, MCT1, and CD147 are colocalized with the mitochondrial reticulum. Western blots showed that cytochrome oxidase (COX), NADH dehydrogenase, LDH, MCT1, and CD147 are abundant in mitochondrial fractions of L6 cells. Interactions among COX, MCT1, and CD147 in mitochondria were confirmed by immunoblotting after immunoprecipitation. These findings support the presence of a mitochondrial lactate oxidation complex associated with the COX end of the electron transport chain that might explain the oxidative catabolism of lactate and, hence, mechanism of the intracellular lactate shuttle.     

Interferon-beta induces the development of type 2 dendritic cells

Suppression of interleukin 12 (IL-12) production by dendritic cells (DCs) has been hypothesized to be a principal mechanism underlying the biological action of interferon (IFN)-beta used for treatment of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system with possible autoimmune origin. How IFN-beta interacts with DCs to inhibit IL-12 production remains unclear. In this study, we found that DCs derived from human blood monocytes, upon culture in the presence of IFN-beta with granulocyte-macrophage colony- stimulating factor (GM-CSF) and IL-4, differentiated into a population expressing CD14- CD1a- HLA-DR+. This population expressed CD123 (IL-3Ralpha). IFN-beta dose-dependently increased IL-3Ralpha+ DCs and decreased CD1a+ DCs. After 7 days' culture with IFN-beta at a concentration of 10 000 U/ml, more than 40% of DCs expressed IL-3Ralpha. IFN-beta, together with GM-CSF and IL-4, also induced maturation of IL-3Ralpha-expressing cells, as reflected by upregulation of HLA-DR and of the costimulatory molecules CD40, CD80 and CD86. In contrast to control DCs, IFN-beta-treated DCs produced predominantly IL-10 but only low levels of IL-12p40. Correspondingly, IFN-beta-treated DCs strongly suppressed IFN-gamma production but enhanced IL-10 production by allogeneic blood mononuclear cells. Our data suggest that IFN-beta in vitro can induce the development of DC2, which provide a permissive environment for Th2 differentiation. This finding represents a novel mechanism for action of IFN-beta in MS.     

Importance of target innervation in recovery from axotomy-induced loss of androgen receptor in rat perineal motoneurons

In adult male rats, axotomy of the spinal nucleus of the bulbocavernosus (SNB) motoneurons transiently down-regulates androgen receptor (AR) immunoreactivity. The present study investigates the importance of target reinnervation in the recovery of AR expression in axotomized SNB motoneurons after short (up to 5 days) and long (1 to 6 weeks) periods of recovery. In the long-term recovery experiment, animals were divided into two groups. In one, the two stumps of the cut pudendal nerve, which carries the axons of the SNB motoneurons, were sutured together immediately after axotomy. In the second group, the proximal stump was ligated immediately after axotomy to prevent target reinnervation. Axotomy of the SNB motoneurons caused a significant down-regulation in AR immunoreactivity within 3 days. At 6 weeks, AR immunoreactivity was still depressed in ligated animals but had recovered to control levels in resutured animals. The recovery in the resutured group was coincident with the first signs of reinnervation of the target perineal muscles, although reinnervation seemed to lag behind AR immunoreactivity. SNB soma size was significantly reduced 2 weeks after axotomy and returned to control levels after 6 weeks of recovery only in the resutured animals. These findings suggest that the target perineal muscles play a role in the regulation of AR expression and androgen sensitivity in the SNB motoneurons, perhaps mediated by muscle-derived trophic factors. © 1995 John Wiley & Sons, Inc.     

<Emphasis Type="Italic">Nocardia zhihengii</Emphasis> sp. nov., an actinobacterium isolated from rhizosphere soil of <Emphasis Type="Italic">Psammosilene tunicoides</Emphasis>

A Nocardia-like actinobacterial strain, designated YIM TG2190^T, was isolated from rhizosphere soil of Psammosilene tunicoides collected from Gejiu, Yunnan province, China. The cells of strain YIM TG2190^T were observed to be Gram-stain positive and non-motile. The strain forms extensively branched substrate mycelia that fragments into rod-shaped elements. The 16S rRNA gene sequence analysis showed that strain YIM TG2190^T is closely related to Nocardia nova (97.5%), Nocardia jiangxiensis (97.1%) and Nocardia miyunensis (96.8%). Growth occurs at 4–30?°C (optimum 28?°C), pH 6.0–8.0 (optimum pH 7.0) and the strain can tolerate NaCl (w/v) up to 3% (optimum 0–1%). The cell walls were found to contain meso-diaminopimelic acid. The whole-cell sugars were identified as glucose, mannose, ribose, galactose, arabinose and fucose. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylglycerol and an unidentified phospholipid. The menaquinones detected were MK-9 (H₂) and MK-8 (H₄). The major fatty acids (>?5%) were found to be C_16:0 (33.9%), summed feature 3 (21.7%), C_18:0 10-methyl TBSA (13.7%) and C_18:1ω9c (7.0%). The DNA G+C content was determined to be 61.1 mol%. DNA-DNA relatedness between the strain YIM TG2190^T and N. nova CGMCC 4.1705^T, N. jiangxiensis CGMCC 4.1905^T and N. miyunensis CGMCC 4.1904^T were 46.9?±?2.6, 36.8?±?1.3, and 35.7?±?2.6%, respectively, values which are less than the threshold value (70%) for the delineation of prokaryotic genomic species. The phenotypic, chemotaxonomic and phylogenetic data indicates that strain YIM TG2190^T represents a novel species of the genus Nocardia, for which the name Nocardia zhihengii sp. nov. is proposed. The type strain is YIM TG2190^T (=KCTC 39596^T?=?DSM 100515^T).     

Influence of cold pretreatment on shoot regeneration from callus in date palm (Phoenix dactylifera L.) cv. ‘Barhee’

Mass propagation of date palm through indirect somatic embryogenesis or organogenesis has attracted the interest of commercial producers. But, this technique still faces some problems that hindered the production of date palm plantlets in vitro. Tissue browning is one of the serious problems that reduce callus growth and shoot regeneration. So the objective of the present study is to investigate the effect of cold pretreatment on callus growth, shoot regeneration, and polyphenol oxidase (PPO) activity during the callus culture. Results showed that a high survival rate of callus cultures (100%) were obtained when cultures were incubated in low temperature (cold treatment) for 45 and 75?days. On the other hand, total amount on phenolic compounds was also reduced to 0.47 and 0.53?mg GAE/g after same period of incubation (45 and 75?days respectively) at low temperature. In additional, our results showed that the highest frequency of shoot formation (66.67 and 73.34, %) and the highest shoot numbers (7.8 and 8.6 shoots/100?mg) were obtained from callus treated with low temperature for 45 and 75?days, respectively.     

Isolation,characterization, cloning and bioinformatics analysis of a novel receptor from black cut worm (Agrotis ipsilon) of Bacillus thuringiensis vip 3Aa toxins

Black cutworm (BCW) is an economically important lepidopteran insect. The control of this insect by a Bt toxin and the understanding of the interaction between the Bt toxin and its receptor molecule were the objectives of this research work. A gene coding for a Vip3A receptor molecule was identified, characterized, and cloned, from the brush border membrane vesicles (BBMV) of the BCW. The nucleotide sequence analysis of the cloned putative Vip3A-receptor gene revealed that the gene was 1.3-kb long and exhibited no homology with any gene in the gene bank. We succeeded in identifying and characterizing most of the Vip3A-receptor gene sequence; and the nucleotide sequence analysis of the cloned putative Vip3A-receptor gene (accession no. KX858809) revealed about 92% of the expected sequence was recovered, which exhibited no homology with any gene in the GenBank.     

Vital Parameters Assessments of Starvation Tolerance of <i>in vitro Populus alba</i> Culture

Populus alba is a large woody deciduous plant. The plant has been introduced to shooting, then multiplication of rooting on Murashige and Skoog (MS) medium. This work was designed to estimate the effect of two factors (low levels of 1-Naphthaleneacetic acid NAA and sucrose) on P. alba response resulting in 6 treatments compared to the control, with twelve measured responses. There was a significant difference in some measurements in morphology, like plantlets fresh-weight, shoot-, root-length, and leaf number. In the physiological measurements, there were significant differences in all the measured parameters. The low concentrations of sucrose and media composition/power (MS grams/L) led to starvation in plants; however, these conditions led to enhancement in some morphological and physiological parameters to overcome the starvation effect, compared to the control. The RAPD-PCR molecular marker (four decamers) was used to evaluate the new individuals’ genetic variation (instability), resulting in a total polymorphism percentage of 50.83%. It was formerly known that the plantlets were identical to each other and to the mother plant. In this study, however, the use of distinct media power, hormonal and sucrose levels resulted in molecular variation reflected in P. alba’s morphological and physiological responses.