Barley β-Galactosidase: Structure, Function, Heterogeneity, and Gene Origin

Barley (Hordeum vulgare) β-galactosidase is composed of a large (45 kDa) and a small (33 kDa) polypeptide. N-terminal sequencing of the polypeptides and antibody reactivity data place the barley enzyme and heterodimeric plant β-galactosidases from jack bean, maize, and wheat in family 35 of the glycosyl hydrolases. Sequence analysis indicates the existence of a subfamily of genes coding for polypeptide precursors that are cleaved to produce the two subunits in heterodimeric β-galactosidases. The heterogeneity of the barley holoenzyme is related, but not restricted, to the N-glycosylation of the small polypeptide. Both polypeptides are essential for the catalytic activity of the enzyme.     

Analyses of Elaeocarpus sphaericus Extract for Antioxidant,Antiproliferative and Gene Repression Activities against HIF-1α and VEGF

The study presents antioxidant, phytochemical, anti-proliferative, and gene repression activities against Hypoxia-inducible factor (HIF-1) alpha and Vascular endothelial growth factor (VEGF) of Elaeocarpus sphaericus extract. Elaeocarpus sphaericus dried and crushed plant leaves were extracted using water and methanol by ASE (Accelerated Solvent Extraction) method. Total phenolic content (TPC) and total flavonoid content (TFC) were used to measure the extracts′ phytochemical activity (TFC). Antioxidant potential of the extracts was measured through DPPH, ABTS, FRAP, and TRP. Methanolic extract of the leaves of E. sphaericus has shown a higher amount of TPC (94.666±4.040 mg/gm GAE) and TFC value (172.33±3.21 mg/gm RE). The antioxidant properties of extracts in the yeast model (Drug Rescue assay) showed promising results. Ascorbic acid, gallic acid, hesperidin, and quercetin were found in the aqueous and methanolic extracts of E. sphaericus at varying amounts, according to a densiometric chromatogram generated by HPTLC analysis. Methanolic extract of E. sphaericus (10 mg/ml) has shown good antimicrobial potential against all bacterial strains used in the study except E. coli. The anticancer activity of the extract in HeLa cell lines ranged from 77.94±1.03 % to 66.85±1.95 %, while it ranged from 52.83±2.57 % to 5.44 % in Vero cell lines at varying concentration (1000 μg/ml–31.2 μg/ml). A promising effect of extract was observed on the expression activity of HIF-1 and VEGF gene through RT-PCR assay.     

Inflammatory,Apoptotic, and Survival Gene Signaling in Alzheimer’s Disease

Aging is associated with an enhanced susceptibility to brain dysfunction, loss of memory, and cognitive decline and significantly influences the quality of life for the affected individual. Recent molecular–genetic approaches have provided powerful insights into common age-related diseases that are both progressive and multifactorial, such as Alzheimer’s disease (AD), and in vitro in AD models. These investigations have uncovered consistent deficits in brain gene signaling mechanisms and neurotrophic substances known to contribute to normal brain function. Inflammatory signaling pathways involving up-regulation of cytosolic phospholipase A₂ and the arachidonic acid cycle, the depletion of the brain-essential fatty acid docosahexaenoic acid (DHA) and DHA-derived neuroprotectin D1, and changes in the expression of key proapoptotic and antiapoptotic members of the Bcl-2 gene family are thought to be major contributors to pathogenic processes in degenerating brain tissue. This review will focus on the roles of stress genes, apoptosis-related genes, and inflammation in the molecular genetics of AD with emphasis on the interactive nature of inflammatory, neurotrophic, and apoptotic signaling and will highlight areas of rapid progress in the characterization of action of DHA and neuroprotectin D1 and address important research challenges. We also attempt to integrate these molecular, genetic, and neurochemical changes with cellular pathways involved in brain aging to formulate an integrated understanding of multifactorial age-related neurologic disease and pharmacotherapeutic strategies that may be useful in the restoration of homeostatic brain function.     

��-Amyloid1�C42 Gene Transfer Model Exhibits Intraneuronal Amyloid, Gliosis, Tau Phosphorylation, and Neuronal Loss

Alzheimer disease is characterized by extracellular β-amyloid (Aβ) plaques and intracellular inclusions containing neurofibrillary tangles of phospho-Tau and intraneuronal Aβ associated with neuronal cell death. We generated a novel gene transfer animal model using lentiviral Aβ_1–42 that resulted in intracellular but not extracellular Aβ accumulations in the targeted rat primary motor cortex. Expression of intracellular Aβ_1–42 led to pathological changes seen in human Alzheimer disease brains, including cell death, inflammatory signs, activation of two Tau kinases, and Tau hyperphosphorylation. Promoting clearance of lentiviral Aβ_1–42 reversed these effects, demonstrating that intraneuronal Aβ_1–42 is a toxic peptide that lies upstream of Tau modification. These studies reveal the role of intracellular Aβ_1–42 in a novel gene transfer animal model, which is a useful tool to study intraneuronal Aβ_1–42-induced pathology in the absence of extracellular plaques. Targeted delivery of Aβ will allow speedy delineation of pathological mechanisms associated with specific neurodegenerative lesions.     

Gene Conversion and Functional Divergence in the β-Globin Gene Family

Different models of gene family evolution have been proposed to explain the mechanism whereby gene copies created by gene duplications are maintained and diverge in function. Ohta proposed a model which predicts a burst of nonsynonymous substitutions following gene duplication and the preservation of duplicates through positive selection. An alternative model, the duplication–degeneration–complementation (DDC) model, does not explicitly require the action of positive Darwinian selection for the maintenance of duplicated gene copies, although purifying selection is assumed to continue to act on both copies. A potential outcome of the DDC model is heterogeneity in purifying selection among the gene copies, due to partitioning of subfunctions which complement each other. By using the d_N/d_S () rate ratio to measure selection pressure, we can distinguish between these two very different evolutionary scenarios. In this study we investigated these scenarios in the -globin family of genes, a textbook example of evolution by gene duplication. We assembled a comprehensive dataset of 72 vertebrate -globin sequences. The estimated phylogeny suggested multiple gene duplication and gene conversion events. By using different programs to detect recombination, we confirmed several cases of gene conversion and detected two new cases. We tested evolutionary scenarios derived from Ohtas model and the DDC model by examining selective pressures along lineages in a phylogeny of -globin genes in eutherian mammals. We did not find significant evidence for an increase in the ratio following major duplication events in this family. However, one exception to this pattern was the duplication of -globin in simian primates, after which a few sites were identified to be under positive selection. Overall, our results suggest that following gene duplications, paralogous copies of -globin genes evolved under a nonepisodic process of functional divergence.[Reviewing Editor: Martin Kreitman]     

Organization, Structure, and Evolution of the Nonadult Rat β-Globin Gene Cluster

The β-globin gene cluster of Wistar rat was extensively cloned and the embryonic genes were mapped and sequenced. Four overlapping λ Dash recombinant clones cover about 31 kb and contain four nonadult β-globin genes, 5′–ε1–γ1–γ2–ψγ3–3′. The ε1 and γ2 are active genes, since their protein products were detected in the fetal stage of the rat (Iwahara et al., J Biochem 119:360–366, 1996). The γ1 locus might be a pseudogene, since the ATA box in the promoter region is mutated to GTA; however, no other defect is observed. The ψγ3 locus is a truncated pseudogene because a 19-base deletion, which causes a shift of the reading frame, is observed between the second nucleotide of the putative codon 68 and codon 76. A sequence comparison suggests that the ψγ3 might be produced by a gene conversion event of the proto-γ-globin gene set. Possible histories of the evolution of rat nonadult β-globin genes are discussed. Received: 6 August 1998 / Accepted: 12 February 1999     

α Cell Function and Gene Expression Are Compromised in Type 1 Diabetes

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Transformation of Pea Lectin Gene and Parasponia Haemoglobin Gene into Rice and Their Expressions

Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene ( pl ) and Parasponia hemoglobin gene ( phb ) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pl and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pl gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pl gene was expressed in 3 out of 18 plants with 17% and 7.5%in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum bv. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.     

Comparison of β-Adrenergic and Glucocorticoid Signaling on Clock Gene and Osteoblast-Related Gene Expressions in Human Osteoblast

Most living organisms exhibit circadian rhythms that are generated by endogenous circadian clocks, the master one being present in the suprachiasmatic nuclei (SCN). Output signals from the SCN are believed to transmit standard circadian time to peripheral tissue through sympathetic nervous system and humoral routes. Therefore, the authors examined the expression of clock genes following treatment with the β-adrenergic receptor agonist, isoprenaline, or the synthetic glucocorticoid, dexamethasone, in cultured human osteoblast SaM-1 cells. Cells were treated with 10^?6 M isoprenaline or 10^?7 M dexamethasone for 2?h and gene expressions were determined using real-time polymerase chain reaction (PCR) analysis. Treatment with isoprenaline or dexamethasone induced the circadian expression of clock genes human period 1 (hPer1), hPer2, hPer3, and human brain and muscle Arnt-like protein 1 (hBMAL1). Isoprenaline or dexamethasone treatment immediately increased hPer1 and hPer2 and caused circadian oscillation of hPer1 and hPer2 with three peaks within 48?h. hPer3 expression had one peak after isoprenaline or dexamethasone treatment. hBMAL expression had two peaks after isoprenaline or dexamethasone treatment, the temporal pattern being in antiphase to that of the other clock genes. Dexamethasone treatment delayed the oscillation of all clock genes for 2–6?h compared with isoprenaline treatment. The authors also examined the expression of osteoblast-related genes hα-1 type I collagen (hCol1a1), halkaline phosphatase (hALP), and hosteocalcin (hOC). Isoprenaline induced oscillation of hCol1a1, but not hALP and hOC. On the other hand, dexamethasone induced oscillation of hCol1a1 and hALP, but not hOC. Isoprenaline up-regulated hCol1a1 expression, but dexamethasone down-regulated hCol1a1 and hALP expression in the first phase. (Author correspondence: togariaf@dpc.agu.ac.jp)     

Effects of Selenium-Enriched Yeast Improved Aflatoxin B1-Induced Changes in Growth Performance,Antioxidation Capacity,IL-2 and IFN-γ Contents,and Gene Expression in Mice

Sixty Kunming mice were randomly assigned into three groups. Mice in a control group were fed a basal diet, while mice in AFB1 group and AFB1-Se group were fed the basal diet supplemented with 250 μg/kg AFB1 or the basal diet supplemented with 250 μg/kg AFB1 and 0.2 mg/kg selenium as selenium-enriched yeast, respectively. On day 30 of the experiment, growth performance, glutathione peroxidase (GSH-Px) activities, total antioxidant capacity (T-AOC) levels, and malondialdehyde (MDA) contents in liver, interleukin-2 (IL-2), and interferon-γ (IFN-γ) contents in serum, and cytochrome P3a11 (Cyp3a11), IL-2, IFN-γ, and GSH-Px1 mRNA levels in liver were determined. The results showed that final weights, weight gains, T-AOC levels, GSH-Px1, and IFN-γ mRNA levels in AFB1-Se group and control group were higher or significantly higher than those in AFB1 group (P < 0.05 or P < 0.01), respectively. Body length gains in AFB1 group were lower than those in the control group (P < 0.05), while there was no significant difference between the AFB1-Se and control groups (P > 0.05). IL-2 contents and liver IL-2 mRNA levels in AFB1-Se group were significantly higher than those in the AFB1 group and control group (P < 0.01), and IL-2 contents in the control group were also significantly higher than those in the AFB1 group (P < 0.01). IFN-γ contents in AFB1-Se group and AFB1 group were significantly higher than those in control group (P < 0.01), while IFN-γ contents in AFB1-Se group were significantly lower than those in AFB1 group (P < 0.01). Cyp3a11 mRNA levels in AFB1-Se group and AFB1 group were significantly higher than those in the control group (P < 0.01). The results indicated that selenium-enriched yeast could partly reduce the toxicity induced by AFB1 in mice, including improving growth performance, antioxidation capacity, IL-2 and IFN-γ contents, and enhancing IL-2, IFN-γ, and GSH-Px1 mRNA levels.

     

Vitamin D Receptor Gene and Aggrecan Gene Polymorphisms and the Risk of Intervertebral Disc Degeneration — A Meta-Analysis

Background

A series of studies have been conducted to evaluate the associations between vitamin D receptor (VDR) and aggrecan variable numbers of tandem repeat (VNTR) polymorphisms and the risk of intervertebral disc degeneration (IDD), but produced conflicting results.

Objective

we performed a meta-analysis to address a more accurate estimation of the associations between the above gene polymorphisms and the risk of IDD.

Methods

A comprehensive literature search was conducted to identify all the relevant studies. The fixed or random effect model was selected based on the heterogeneity test among studies evaluated using the I ². Publication bias was estimated using Begg''s funnel plots and Egger''s regression test.

Results

A total of 9, 5, 3, and 7 studies were finally included in the analyses for the associations between the VDR TaqI (rs731236), FokI (rs2228570), ApaI (rs7975232), or aggrecan VNTR polymorphisms and the risk of IDD, respectively. The combined results showed that none of the VDR (TaqI, FokI, ApaI) polymorphisms were significantly associated with the risk of IDD. In contrast, the alleles with shorter VNTR length was found to significantly increase the risk of IDD (≦25 vs. >25: OR = 1.850, 95%CI 1.477–2.318; ≦23 vs. >23: OR = 1.955, 95%CI 1.41–2.703). Subgroup analysis confirmed the above results. After excluding studies deviated from Hardy-Weinberg equilibrium (HWE) in controls, no other studies were found to significantly influence the pooled effects in each genetic model. No potential publication bias was detected.

Conclusion

This meta-analysis suggested that the alleles with shorter VNTR length significantly increased the risk of IDD, while the VDR (TaqI, FokI, ApaI) gene polymorphisms were not significantly associated with the risk of IDD. Since potential confounders could not be ruled out completely, further studies are needed to confirm these results.     

Identification and Characteristics of a Novel E1 Like Gene nUBE1l in Human test

The selective degradation of many short一lived or abnormal Proteins in eukaryotic cells 15 carried out by the ubiquitin system.In this Pathway,Proteins are targeted for degradation by covalent ligation to ubiquitin,a highly conserved 76一resid…