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Biochemical Evidence (biochemical + evidence)
Selected AbstractsMolecular and Biochemical Evidence for Phenylpropanoid Synthesis and Presence of Wall-linked Phenolics in Cotton FibersJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 7 2009Ling Fan Abstract The mature cotton (Gossypium hirsutum L.) fiber is a single cell with a typically thickened secondary cell wall. The aim of this research was to use molecular, spectroscopic and chemical techniques to investigate the possible occurrence of previously overlooked accumulation of phenolics during secondary cell wall formation in cotton fibers. Relative quantitative reverse transcription-polymerase chain reaction analysis showed that GhCAD6 and GhCAD1 were predominantly expressed among seven gene homologs, only GhCAD6 was up-regulated during secondary wall formation in cotton fibers. Phylogenic analysis revealed that GhCAD6 belonged to Class I and was proposed to have a major role in monolignol biosynthesis, and GhCAD1 belonged to Class III and was proposed to have a compensatory mechanism for monolignol biosynthesis. Amino acid sequence comparison showed that the cofactor binding sites of GhCADs were highly conserved with high similarity and identity to bona fide cinnamyl alcohol dehydrogenases. The substrate binding site of GhCAD1 is different from GhCAD6. This difference was confirmed by the different catalytic activities observed with the enzymes. Cell wall auto-fluorescence, Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) and chemical analyses confirmed that phenolic compounds were bound to the cell walls of mature cotton fibers. Our findings may suggest a potential for genetic manipulation of cotton fiber properties, which are of central importance to agricultural, cotton processing and textile industries. [source] Biochemical evidence that an S431F mutation in acetylcholinesterase-1 of Aphis gossypii mediates resistance to pirimicarb and omethoatePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2004Dr Jürgen Benting Abstract Molecular changes in acetylcholinesterase (AChE) leading to target-site resistance to carbamate and organophosphate insecticides have recently been identified. Of particular interest is the S431F mutation in ace2 and its orthologue ace1 of Myzus persicae Sulzer and Aphis gossypii Glover, respectively. This mutation has been correlated with resistance to pirimicarb, but biochemical evidence has not yet been provided. Here, we describe for the first time that recombinantly expressed AChE1 from A gossypii carrying the S431F mutation is insensitive to pirimicarb and omethoate, but sensitive to demeton-S-methyl and hypersensitive to carbofuran. Furthermore, site-directed mutagenesis of the serine residue at position 431 in ace1 from a pirimicarb-susceptible clone of A gossypii conferred insensitivity to pirimicarb. We conclude that AChE1 of A gossypii is the target of toxicological relevance of carbamates and organophosphates. Copyright © 2004 Society of Chemical Industry [source] Schizophrenia; from structure to function with special focus on the mediodorsal thalamic prefrontal loopACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2009B. Pakkenberg Objective:, To describe structural and biochemical evidence from postmortem brains that implicates the reciprocal connections between the mediodorsal thalamic nucleus and the prefrontal cortex in cognitive symptoms of schizophrenia. Method:, The estimation of the regional volumes and cell numbers was obtained using stereological methods. The biochemical analyses of molecular expression in postmortem brain involve quantitative measurement of transcripts and proteins by in-situ (RNA) or Western blot/autoradiography in brains from patients with schizophrenia and comparison subjects. Results:, Stereological studies in postmortem brain from patients with schizophrenia have reported divergent and often opposing findings in the total number of neurons and volume of the mediodorsal (MD) thalamic nucleus, and to a lesser degree in its reciprocally associated areas of the prefrontal cortex. Similarly, quantitative molecular postmortem studies have found large inter-subject and between-study variance at both the transcript and protein levels for receptors and their interacting molecules of several neurotransmitter systems in these interconnected anatomical regions. Combined, large variation in stereological and molecular studies indicates a complex and heterogeneous involvement of the MD thalamic-prefrontal loop in schizophrenia. Conclusion:, Based on a considerable heterogeneity in patients suffering from schizophrenia, large variation in postmortem studies, including stereological and molecular postmortem studies of the MD thalamus and frontal cortex, might be expected and may in fact partly help to explain the variable endophenotypic traits associated with this severe psychiatric illness. [source] The feeding behavior of Trichogramma brassicae: new evidence for selective ingestion of solid foodENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000Z.X. Wu Abstract A descriptive study of the feeding behavior and structures of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) was conducted. Based on direct observational and biochemical evidence, larvae feed predominantly on particulate materials, starting ca. 25 h post-oviposition. Feeding lasted for ca. 9 h, at 25±1 °C. During this feeding period the shape of the larvae changed from vermiform to pyriform and then to sacciform, resulting in a ca. 40-fold increase in body size. Larvae used elaborate feeding behaviors as they pulled solid food particles to their oral opening, broke small particles from larger ones, and took the particles into the stomodaeum, which is a powerful pump. In the stomodaeum, peristaltic movement further macerated the particles, which eventually passed through the cardiac valve into the midgut. As indicated by changes in fluorescently labeled casein, digestive enzymes aid in the extra-oral chemical digestion of food. The contents of the gut, during and shortly after feeding, were almost entirely closely packed solid particles. The behavioral activity of feeding larvae centered almost exclusively on processing and ingesting solid food particles. The rapid larval growth is much more plausibly explained by their feeding on the highly concentrated nutrients found in solid foods, rather than the extensive concentration required if dilute liquids were the principal source of nutrients. The implications of these findings for the development of practical artificial diets are discussed. [source] Genetic, immunological and biochemical evidence for a Rnf complex in the acetogen Acetobacterium woodiiENVIRONMENTAL MICROBIOLOGY, Issue 6 2009Eva Biegel Summary Acetogenic bacteria grow by the oxidation of various substrates coupled to the reduction of carbon dioxide (acetogenesis) or other electron acceptors but the mechanisms of energy conservation are still enigmatic. Here, we report the presence of a rnf gene cluster rnfCDGEAB in Acetobacterium woodii that is speculated to encode a novel, energy-conserving ferredoxin:NAD+ -oxidoreductase complex composed of at least six different subunits. Transcriptional analysis revealed that the genes constitute an operon. RnfC and RnfG were heterologously produced and antibodies were generated. Western blot analyses demonstrated that these subunits were produced and are associated with the cytoplasmic membrane. The subunits were present in cells respiring with either carbon dioxide or caffeate. A preparation with NADH dehydrogenase activity was obtained from detergent solubilized membranes that contained RnfC and RnfG. [source] Identification of phospholipids as new components that assist in the in vitro trimerization of a bacterial pore proteinFEBS JOURNAL, Issue 3 2001Hans De Cock The in vitro trimerization of folded monomers of the bacterial pore protein PhoE, into its native-like, heat- and SDS-stable form requires incubations with isolated cell envelopes and Triton X-100. The possibility that membranes could be isolated that are enriched in assembly factors required for assembly of the pore protein was now investigated. Fractionation of total cell envelopes of Escherichia coli via various techniques indeed revealed the existence of membrane fractions with different capacities to support assembly in vitro. Fractions containing mainly inner membrane vesicles supported the formation of trimers that were associated with these membrane vesicles. However, only a proportion of these trimers were heat- and SDS-stable and these were formed with slow kinetics. In contrast, fractions containing mainly outer membrane vesicles supported formation of high amounts of heat-stable trimers with fast kinetics. We identified phospholipids as active assembly components in these membranes that support trimerization of folded monomers in a process with similar characteristics as observed with inner membrane vesicles. Furthermore, phospholipids strongly stimulate the kinetics of trimerization and increase the final yield of heat-stable trimers in the context of outer membranes. We propose that lipopolysaccharides stabilize the assembly competent state of folded monomers as a lipochaperone. Phospholipids are involved in converting the folded monomer into new assembly competent intermediate with a short half-life that will form heat-stable trimers most efficiently in the context of outer membrane vesicles. These results provide biochemical evidence for the involvement of different lipidic components at distinct stages of the porin assembly process. [source] PCNA clamp facilitates action of DNA cytosine methyltransferase 1 on hemimethylated DNAGENES TO CELLS, Issue 10 2002Tetsuo Iida Background: Proliferating cell nuclear antigen (PCNA) is a ring-shaped protein known as a processivity factor of DNA polymerase ,. In addition to this role, PCNA interacts with a number of other proteins to increase their local concentration at replicated DNA sites. DNA cytosine methyltransferase 1 (Dnmt1), which preserves epigenetic signals by completing the methylation of hemimethylated DNA after DNA replication, has been indicated as one of these PCNA binding proteins by a previous work. However, the molecular mechanisms and functional significance of their association have not yet been studied. Results: Dnmt1 can be readily isolated from nuclear extracts by PCNA affinity chromatography. Studies of the interactions between the two proteins demonstrate that the N-terminal region of Dnmt1, which contains a typical PCNA binding motif, has core PCNA binding activity, and that the remaining portion of the protein exerts a negative influence on the interaction of Dnmt1 with PCNA. The affinity of Dnmt1 for DNA is much higher for DNA bound by PCNA than for free DNA. Furthermore, DNA methylation assays with hemimethylated DNA as a substrate revealed that PCNA clamp-bound DNA is methylated more efficiently by Dnmt1 than is free DNA. Conclusion: These results provide the first biochemical evidence that physical interactions between PCNA and Dnmt1 facilitate the methylation of newly neplicated DNA, on which PCNA remains associated as a functional clamp. [source] Proteasome inhibition suppresses Schwann cell dedifferentiation in vitro and in vivoGLIA, Issue 16 2009Hyun Kyoung Lee Abstract The ubiquitin-proteasome system (UPS), lysosomes, and autophagy are essential protein degradation systems for the regulation of a variety of cellular physiological events including the cellular response to injury. It has recently been reported that the UPS and autophagy mediate the axonal degeneration caused by traumatic insults and the retrieval of nerve growth factors. In the peripheral nerves, axonal degeneration after injury is accompanied by myelin degradation, which is tightly related to the reactive changes of Schwann cells called dedifferentiation. In this study, we examined the role of the UPS, lysosomal proteases, and autophagy in the early phase of Wallerian degeneration of injured peripheral nerves. We found that nerve injury induced an increase in the ubiquitin conjugation and lysosomal-associated membrane protein-1 expression within 1 day without any biochemical evidence for autophagy activation. Using an ex vivo explant culture of the sciatic nerve, we observed that inhibiting proteasomes or lysosomal serine proteases prevented myelin degradation, whereas this was not observed when inhibiting autophagy. Interestingly, proteasome inhibition, but not leupeptin, prevented Schwann cells from inducing dedifferentiation markers such as p75 nerve growth factor receptor and glial fibrillary acidic protein in vitro and in vivo. In addition, proteasome inhibitors induced cell cycle arrest and cellular process formation in cultured Schwann cells. Taken together, these findings indicate that the UPS plays a role in the phenotype changes of Schwann cells in response to nerve injury. © 2009 Wiley-Liss, Inc. [source] Glutamatergic systems in Alzheimer's diseaseINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue S1 2003Paul T. Francis Abstract Glutamate is the major transmitter of the brain and is involved in all aspects of cognitive function since it is the transmitter of cortical and hippocampal pyramidal neurones. Furthermore, glutamate and glutamate receptors are involved in long-term potentiation, a process believed to underlie learning and memory. Histological studies indicate loss of pyramidal neurones and their synapses in Alzheimer's disease (AD), this together with biochemical evidence suggests presynaptic (and postsynaptic) glutamatergic hypoactivity. This represents a ,double blow' as the activity of glutamatergic neurones is heavily influenced by the cholinergic system, which is also dysfunctional in AD. The clinical relevance of these changes is emphasised because glutamatergic and cholinergic dysfunction are strong correlates of cognitive decline in AD. The mechanism by which glutamatergic (and cholinergic) cells die is likely to be a combination of necrosis and apoptosis caused by a range of factors which include tangle formation and the effects of too much and too little glutamatergic neurotransmission. Copyright © 2003 John Wiley & Sons, Ltd. [source] Co-localization of PARP-1 and lamin B in the nuclear architecture: A halo-fluorescence- and confocal-microscopy studyJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2005Melita Vidakovi Abstract A functional interaction between poly(ADP-ribose) polymerase-1 (PARP-1) and lamin B has recently been proposed by nuclear fractionation, crosslinking, and immunoprecipitation experiments. Here we use fluorescence microscopy to verify and extend these findings. We analyze nuclear halo preparations by fluorescence in situ immuno staining (FISIS), which shares attributes with traditional nuclear fractionation techniques, and by confocal laser scanning microscopy (CLSM). The results agree in that a major part of the enzyme co-localizes with lamin B under physiological conditions, where PARP-1 only has basal activity. After DNA damage and the associated activation of PARP-1, and during the subsequent entry into apoptosis, dramatic changes occur: a gradual release of the enzyme from the lamina, accompanied by its accumulation in nucleoli. Our observations are in line with biochemical evidence for lamin B-PARP-1 interactions under physiological conditions and suggest ways by which these interactions are modified to support PARP-functions in damage and its fate in apoptosis. © 2005 Wiley-Liss, Inc. [source] Hepatitis C infection in children: A Melbourne perspectiveJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 4 2000B Karim Objective: To examine the clinical spectrum of hepatitis C virus (HCV) infected children in our care by determining presentation, mode of acquisition, degree of co-infection, biochemical evidence of persisting hepatitis and treatment outcome. Methodology: A retrospective review of the medical records of all children attending the Royal Children's Hospital, Melbourne, between 1990 and 1998, who had antibodies to HCV infection detected. Detailed clinical information, investigations and the results of treatment were extracted from the clinical notes. Results: A total of 94 children (age range 2 weeks to 19.7 years) were identified, of whom nine had passive transfer of maternal antibodies from HCV-positive mothers and were excluded from analysis. Sixty-seven children (79%) were infected by transfusion of blood or blood products. Perinatal transmission occurred in 11 children (13%), and six children (7%) had a history of i.v. drug abuse. The majority of children were asymptomatic at presentation. Of the 65 patients tested for HCV-ribonucleic acid, 43 (66%) were positive. Fifty-seven cases had serial alanine aminotransaminase (ALT) measurements over a mean of 28 months. Of these, 38 (67%) had an abnormal ALT. Ten cases (12%) were co-infected with hepatitis B virus, HIV or both. Of 12 patients treated with interferon, four responded with normalisation of ALT from 3 to 12 months post-commencement of therapy. Conclusions: Although HCV was largely an asymptomatic condition in our clinic population, more than half the patients had biochemical evidence of ongoing liver damage. Given the chronicity of this infection in the majority of patients and the long-term risks of cirrhosis and hepatocellular carcinoma, children with HCV infection represent a high-risk group worthy of regular follow up. [source] Preventive effect of Aegle marmelos leaf extract on isoprenaline-induced myocardial infarction in rats: biochemical evidenceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2005P. Stanely Mainzen Prince We have evaluated the preventive effects of an aqueous Aegle marmelos leaf extract (AMLEt) in isoprenaline (isoproterenol)-induced myocardial infarction in rats. Rats were pretreated with AMLEt (50, 100 or 200 mg kg,1) for 35 days. After the treatment period, isoprenaline (200 mg kg,1) was administered subcutaneously to rats at an interval of 24 h for two days. The activity of creatine kinase (CK) and lactate dehydrogenase (LDH) was significantly increased in serum and significantly decreased in heart of isoprenaline-treated rats. Pretreatment with AMLEt decreased the activity of CK and LDH in serum and increased them in the heart. The activity of sodium-potassium dependent adenosine triphosphatase (Na+K+ATPase) was significantly decreased while the activity of calcium dependent adenosine triphosphatase (Ca2+ATPase) was simultaneously increased in the heart and aorta. AMLEt pretreatment increased the activity of Na+K+ATPase and decreased the activity of Ca2+ATPase in the heart and aorta simultaneously. The levels of cholesterol and triglycerides increased, while the levels of phospholipids decreased in the heart and aorta of isoprenaline-treated rats. In AMLEt-pretreated rats the levels of cholesterol and triglycerides decreased whereas phospholipids increased in heart and aorta. All the deranged biochemical parameters were restored with 200 mg kg,1 AMLEt. Similarly ,-tocopherol (60 mg kg,1)-pretreatment to isoprenaline-treated rats exhibited a significant effect on all the parameters studied. The results from this study may have clinical relevance. [source] Acid-base balance of cats with chronic renal failure: effect of deterioration in renal functionJOURNAL OF SMALL ANIMAL PRACTICE, Issue 6 2003J. Elliott In a previous cross-sectional study of feline chronic renal failure (CRF), metabolic acidosis was identified in 52·6 per cent of animals with severe renal failure (plasma creatinine concentration > 400 umol/litre). The aim of this longitudinal study was to determine whether metabolic acidosis preceded or accompanied a deterioration in renal function in cats with CRF. Data were analysed from 55 cats with CRF that had been followed longitudinally for at least four months. Twenty-one cases showed deterioration in renal function over the period of the study, as evidenced by significant rises in their plasma creatinine concentrations and decreases in bodyweight. In five of the 21 cases, acidaemia accompanied the deterioration in renal function. Only one of these cats had evidence of metabolic acidosis before renal function deterioration. One other case developed metabolic acidosis without a rise in plasma creatinine concentration. These data suggest that biochemical evidence of metabolic acidosis does not generally occur until late in the course of feline CRF. [source] Assessment of acid-base status of cats with naturally occurring chronic renal failureJOURNAL OF SMALL ANIMAL PRACTICE, Issue 2 2003J. Elliott Metabolic acidosis is reported to be a common complication of feline chronic renal failure (CRF) but acid-base status of feline patients with this disease is rarely assessed by general practitioners. A cross-sectional study involving 59 cases of naturally occurring feline CRF was conducted to determine the prevalence of acid-base disturbances. Cases were categorised on the basis of their plasma creatinine concentrations as mild, moderate or severe. A group of 27 clinically healthy, age-matched cats was assessed for comparison. A low venous blood pH (<7·270) was found in 10 of the 19 severe cases (52·6 per cent), three of the 20 moderate cases (15 per cent) and none of the 20 mild cases. Acidaemia was associated with an increased anion gap contributed to by both low plasma bicarbonate and low chloride ion concentrations. Biochemical analysis of urine samples showed urine pH to decrease with increasing severity of renal failure. Urinary loss of bicarbonate was not associated with the occurrence of acidaemia and there was a tendency for urinary ammonium ion excretion to decrease as the severity of renal failure increased. Cats with naturally occurring CRF do not show plasma biochemical evidence of acid-base disturbances until the disease is advanced. [source] Clinical improvement in patients with decompensated liver disease caused by hepatitis B after treatment with lamivudineLIVER TRANSPLANTATION, Issue 6 2000Craig A. Sponseller Lamivudine is effective in inhibiting hepatitis B virus (HBV) replication, and its clinical use in patients with chronic hepatitis B is associated with improvements in serum aminotransferase levels and liver histopathologic characteristics. Few data are available on its use in patients with advanced liver disease. We report on the outcomes of 5 patients with hepatic decompensation caused by chronic hepatitis B treated long term with lamivudine. All patients were adult white men seropositive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) before therapy. All 5 patients had biopsy-proven cirrhosis with clinical and biochemical evidence of hepatic decompensation. Two patients had Child's class C cirrhosis; 2 patients, class B; and 1 patient, class A (although this patient had persistent portasystemic encephalopathy and developed variceal bleeding). HBV DNA became undetectable in all patients and remained so throughout the study. Both patients with Child's class C and 1 patient with class B cirrhosis had significant clinical improvement. Child-Pugh scores improved from 12 to 7 and 11 to 7 in the 2 patients with Child's class C cirrhosis, and the patient with class B cirrhosis had complete resolution of troublesome encephalopathy. Serum aminotransferase, albumin, and total bilirubin levels improved significantly in 3 of 5 patients. One patient with Child's class B cirrhosis underwent orthotopic liver transplantation at week 13 after dramatic increases in liver tests and clinical worsening. The patient subsequently cleared HBeAg and HBsAg from serum posttransplantation. In conclusion, prolonged therapy with lamivudine resulted in improved serum biochemical values and loss of HBV DNA in patients with decompensated cirrhosis. Clinical improvements, reflected in Child-Pugh classification and functional status, may also occur, particularly among those with Child's class C disease initially. [source] Analysis of the requirements for pilus biogenesis at the outer membrane usher and the function of the usher C-terminusMOLECULAR MICROBIOLOGY, Issue 2 2006Stephane Shu Kin So Summary Uropathogenic strains of Escherichia coli assemble type 1 and P pili to colonize the bladder and kidney respectively. These pili are prototype structures assembled by the chaperone/usher secretion pathway. In this pathway, a periplasmic chaperone works together with an outer membrane (OM) usher to control the folding of pilus subunits, their assembly into a pilus fibre and secretion of the fibre to the cell surface. The usher serves as the assembly and secretion platform in the OM. The usher has distinct functional domains, with the N-terminus providing the initial targeting site for chaperone,subunit complexes and the C-terminus required for subsequent stages of pilus biogenesis. In this study, we investigated the molecular interactions occurring at the usher during pilus biogenesis and the function of the usher C-terminus. We provide genetic and biochemical evidence that the usher functions as a complex in the OM and that interaction of the pilus adhesin with the usher is critical to prime the usher for pilus biogenesis. Analysis of C-terminal truncation and substitution mutants of the P pilus usher PapC demonstrated that the C-terminus is required for proper binding of chaperone,subunit complexes to the usher and plays an important role in assembly of complete pili. [source] The distribution and expression of a biotrophy-related gene, CIH1, within the genus ColletotrichumMOLECULAR PLANT PATHOLOGY, Issue 4 2000Sarah E. Perfect During the biotrophic phase of the infection process of the hemibiotrophic anthracnose fungus Colletotrichum lindemuthianum, an intracellular hypha develops within epidermal cells of its host, Phaseolus vulgaris. This is followed by the formation of secondary hyphae during the necrotrophic phase. Previous work using a monoclonal antibody, UB25, has identified a glycoprotein that is specific to the interfacial matrix that forms between the wall of the intracellular hypha and the invaginated host plasma membrane. The gene encoding the protein identified by UB25 was cloned by immunoscreening and designated CIH1. The predicted amino acid sequence revealed a proline-rich glycoprotein, and biochemical evidence suggested that it formed a cross-linked structure at the biotrophic interface. Although CIH1 is a fungal gene, its product has several similarities to plant cell wall proteins. In this paper, we have surveyed the distribution and expression of CIH1 within the genus Colletotrichum, encompassing both necrotrophic and hemibiotrophic species. The results show that homologues of the CIH1 gene are present in all the Colletotrichum species tested. Northern blot studies of the time course of the infection process in planta have shown that CIH1 is expressed by both C. lindemuthianum in bean and C. trifolii in alfalfa during the biotrophic phase of fungal development. Immunofluorescence labelling of infected epidermal strips with UB25 revealed that the intracellular hyphae formed by C. destructivum as it infects alfalfa were specifically labelled in a similar way to those formed by C. lindemuthianum in bean. Northern and Western analysis showed that CIH1 was also expressed by C. lindemuthianum in vitro, though not constitutively. Overall, the evidence supports a role for CIH1 in biotrophy within the genus Colletotrichum. [source] Olive oil production on bronze age Crete: nutritional properties, processing methods and storage life of Minoan olive oilOXFORD JOURNAL OF ARCHAEOLOGY, Issue 1 2002F.R. Riley Archaeological studies on olive oil produced in Crete in the Bronze Age focus primarily on aspects such as the period when olive cultivation became widespread, the number of olive trees cultivated, or the quantity of oil stored in the Minoan palaces. Olive oil is however an organic substance, a perishable product, the nutritional and storage properties of which are determined by environmental, agronomic, processing and storage conditions. In this paper archaeological, environmental and biochemical evidence is combined to present a comprehensive picture of the potential quality, nutritional and storage properties of Minoan olive oil. The comparative evidence presented suggests that Minoan olive oil was equal in quality to the cold-pressed virgin olive oils produced today, and as such, the oil was nutritionally important in the Bronze Age and a valuable trade commodity. [source] Malnutrition-Associated Rash of Cystic FibrosisPEDIATRIC DERMATOLOGY, Issue 5 2000Gary L. Darmstadt M.D. We measured essential fatty acid (EFA) levels in the serum of a 4-month-old girl with an erythematous, desquamating, periorificially accentuated rash in association with malnutrition and her 2-year-old sister who was diagnosed concurrently with CF but had no rash or signs of malnutrition. Both patients had biochemical evidence of EFA deficiency, suggesting that development of the rash is multifactorial. Clinical presentation, management, and possible modes of pathogenesis of the rash are reviewed. Pathogenesis of the rash appears to involve a complex interaction among deficiencies of EFAs, zinc, protein, and possibly copper, leading to disordered prostaglandin metabolism or cytokine production, or free radical-induced damage to cellular membranes due to a lack of nutrient-derived protective antioxidants. [source] Biochemical evidence that an S431F mutation in acetylcholinesterase-1 of Aphis gossypii mediates resistance to pirimicarb and omethoatePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2004Dr Jürgen Benting Abstract Molecular changes in acetylcholinesterase (AChE) leading to target-site resistance to carbamate and organophosphate insecticides have recently been identified. Of particular interest is the S431F mutation in ace2 and its orthologue ace1 of Myzus persicae Sulzer and Aphis gossypii Glover, respectively. This mutation has been correlated with resistance to pirimicarb, but biochemical evidence has not yet been provided. Here, we describe for the first time that recombinantly expressed AChE1 from A gossypii carrying the S431F mutation is insensitive to pirimicarb and omethoate, but sensitive to demeton-S-methyl and hypersensitive to carbofuran. Furthermore, site-directed mutagenesis of the serine residue at position 431 in ace1 from a pirimicarb-susceptible clone of A gossypii conferred insensitivity to pirimicarb. We conclude that AChE1 of A gossypii is the target of toxicological relevance of carbamates and organophosphates. Copyright © 2004 Society of Chemical Industry [source] The Ginkgo biloba extract, EGb 761, fails to reduce brain infarct size in rats after transient, middle cerebral artery occlusion in conditions of unprevented, ischemia-induced feverPHYTOTHERAPY RESEARCH, Issue 6 2006Keli Carina Miltus de Lima Abstract There is much biochemical evidence, but very few studies in animal models of stroke in vivo, to suggest that Ginkgo biloba (EGb 761) may offer neuroprotection against regional, ischemic brain damage; additional investigations are needed to ensure future clinical trials. This study reports the effects of EGb 761 given acutely or chronically before ischemia. Rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h and the brain infarct size was assessed 24 h later. Dipyrone (100 mg/kg, i.p.) was injected 30 min before ischemia, and 2.5 and 5.5 h after ischemia, to reduce ischemia-induced fever. EGb 761 (Tebonin®) was given acutely (200 mg/kg, p.o., 60 min before ischemia) or chronically (100 mg/kg, p.o., once daily, for 14 days before ischemia). Acute or chronic treatment with EGb 761, either alone or in combination with dipyrone, did not reduce the infarct size compared with saline alone (p > 0.05). Dipyrone failed to prevent ischemia-induced fever during the intra-ischemic period (p > 0.05 vs saline; p < 0.001 vs sham). In the reperfusion phase, dipyrone reduced fever to normothermic levels in the group treated acutely with EGb 761 (p < 0.01 vs saline, p > 0.05 vs sham) but not after chronic EGb 761 (p < 0.01 vs sham), indicating possible pharmacokinetic interaction. In conclusion, within the context of unprevented, ischemia-induced fever, the present results demonstrate that EGb 761 has no significant effect on brain infarct size. Copyright © 2006 John Wiley & Sons, Ltd. [source] Identification of overlapping but distinct cAMP and cGMP interaction sites with cyclic nucleotide phosphodiesterase 3A by site-directed mutagenesis and molecular modeling based on crystalline PDE4BPROTEIN SCIENCE, Issue 8 2001Wei Zhang Abstract Cyclic nucleotide phosphodiesterase 3A (PDE3A) hydrolyzes cAMP to AMP, but is competitively inhibited by cGMP due to a low kcat despite a tight Km. Cyclic AMP elevation is known to inhibit all pathways of platelet activation, and thus regulation of PDE3 activity is significant. Although cGMP elevation will inhibit platelet function, the major action of cGMP in platelets is to elevate cAMP by inhibiting PDE3A. To investigate the molecular details of how cGMP, a similar but not identical molecule to cAMP, behaves as an inhibitor of PDE3A, we constructed a molecular model of the catalytic domain of PDE3A based on homology to the recently determined X-ray crystal structure of PDE4B. Based on the excellent fit of this model structure, we mutated nine amino acids in the putative catalytic cleft of PDE3A to alanine using site-directed mutagenesis. Six of the nine mutants (Y751A, H840A, D950A, F972A, Q975A, and F1004A) significantly decreased catalytic efficiency, and had kcat/Km less than 10% of the wild-type PDE3A using cAMP as substrate. Mutants N845A, F972A, and F1004A showed a 3- to 12-fold increase of Km for cAMP. Four mutants (Y751A, H840A, D950A, and F1004A) had a 9- to 200-fold increase of Ki for cGMP in comparison to the wild-type PDE3A. Studies of these mutants and our previous study identified two groups of amino acids: E866 and F1004 contribute commonly to both cAMP and cGMP interactions while N845, E971, and F972 residues are unique for cAMP and the residues Y751, H836, H840, and D950 interact with cGMP. Therefore, our results provide biochemical evidence that cGMP interacts with the active site residues differently from cAMP. [source] TcYSL3, a member of the YSL gene family from the hyper-accumulator Thlaspi caerulescens, encodes a nicotianamine-Ni/Fe transporterTHE PLANT JOURNAL, Issue 1 2007Delphine Gendre Summary The two main features of plant hyper-accumulator species are the massive translocation of heavy metal ions to the aerial parts and their tolerance to such high metal concentrations. Recently, several lines of evidence have indicated a role for nicotianamine (NA) in metal homeostasis, through the chelation and transport of NA,metal complexes. The function of transport of NA,metal chelates, required for the loading and unloading of vessels, has been assigned to the Yellow Stripe 1 (YSL)-Like family of proteins. We have characterized three YSL genes in Thlaspi caerulescens in the context of hyper-accumulation. The three YSL genes are expressed at high rates compared with their Arabidopsis thaliana homologs but with distinct patterns. While TcYSL7 was highly expressed in the flowers, TcYSL5 was more highly expressed in the shoots, and the expression of TcYSL3 was equivalent in all the organs tested. In situ hybridizations have shown that TcYSL7 and TcYSL5 are expressed around the vasculature of the shoots and in the central cylinder in the roots. The exposure to heavy metals (Zn, Cd, Ni) does not affect the high and constitutive expression of the TcYSL genes. Finally, we have demonstrated by mutant yeast complementation and uptake measurements that TcYSL3 is an Fe/Ni,NA influx transporter. This work provides therefore molecular, histological and biochemical evidence supporting a role for YSL transporters in the overall scheme of NA and NA,metal, particularly NA,Ni, circulation in a metal hyper-accumulator plant. [source] Recrudescent Tobacco Exposure Following Heart Transplantation: Clinical Profiles and Relationship with Athero-Thrombosis Risk MarkersAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2005Mandeep R. Mehra To identify tobacco recidivism among 86 heart transplant recipients who were smokers but demonstrated compliance with a smoking cessation program pre-transplant, we used a questionnaire and randomly tested urine for nicotine and its by-products. In 36 patients, we also evaluated circulating levels of HS-CRP, homocysteine and MPV. Twenty-eight (32.5%) of 86 patients met our definition for tobacco exposure. In this cohort, 28 (32.5%) of 86 patients met our definition for tobacco exposure. Of these 28, 12 patients self-reported tobacco use and demonstrated biochemical verification; 14 patients demonstrated only biochemical evidence of significant tobacco exposure; 2 patients self-reported tobacco use but did not demonstrate biochemical positivity. Smoking cessation within 6 months of transplantation (r = 0.52) and time post-transplantation (r = 0.43) were independent predictors for recidivism of tobacco use, p < 0.01. No differences in HS-CRP, homocysteine and MPV levels were noted among the groups. Our investigation demonstrates a high rate of tobacco recidivism among heart transplant recipients, yet few admit to it. The adverse effects of tobacco do not appear to be directly modulated by an effect on athero-thrombotic risk markers. [source] Identification of endo- and exo-polygalacturonase activity in Lygus hesperus (Knight) salivary glands,ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2009Maria de la Paz Celorio-Mancera Abstract Polygalacturonase (PG) activity found in the salivary gland apparatus of the western tarnished plant bug (WTPB, Lygus hesperus Knight) has been thought to be the main chemical cause of the damage inflicted by this mirid when feeding on its plant hosts. Early viscosity and thermal stability studies of the PG activity in L. hesperus protein extracts were difficult to interpret. Thus, it has been suggested that one or more PG protein(s) with different hydrolytic modes of action are produced by this mirid. In order to understand the quantitative complexity of the WTPB salivary PG activity, PG purification from a protein extract from salivary glands excised from L. hesperus insects was performed using affinity and ion exchange chromatography. To elucidate the qualitative complexity of the purified PGs, the digestion products generated by the PGs were separated using high performance anion exchange chromatography with pulsed amperometric detection. At least five PG proteins were detected; these differing in terms of their glycosylation, mass-to-charge ratios, and/or molecular mass. The characterization of the products generated by these PGs showed that endo- and exo-acting PGs are produced by WTPB. Although none of the PGs was purified to homogeneity, the present work provides biochemical evidence of a multiplicity of PGs that degrade the pectin component of the plant tissue in different fashions. The implications of these findings affect the understanding of WTPB feeding damage and, potentially, help identify ways to control this important crop pest. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley-Liss, Inc. [source] The high-resolution structure of pig heart succinyl-CoA:3-oxoacid coenzyme A transferaseACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2010Shu-Fen Coker The enzyme succinyl-CoA:3-oxoacid coenzyme A transferase (SCOT) participates in the metabolism of ketone bodies in extrahepatic tissues. It catalyses the transfer of coenzyme A (CoA) from succinyl-CoA to acetoacetate with a classical ping-pong mechanism. There is biochemical evidence that the enzyme undergoes conformational changes during the reaction, but no domain movements have been reported in the available crystal structures. Here, a structure of pig heart SCOT refined at 1.5,Å resolution is presented, showing that one of the four enzyme subunits in the crystallographic asymmetric unit has a molecule of glycerol bound in the active site; the glycerol molecule is hydrogen bonded to the conserved catalytic glutamate residue and is likely to occupy the cosubstrate-binding site. The binding of glycerol is associated with a substantial relative movement (a 13° rotation) of two previously undefined domains that close around the substrate-binding site. The binding orientation of one of the cosubstrates, acetoacetate, is suggested based on the glycerol binding and the possibility that this dynamic domain movement is of functional importance is discussed. [source] Hepatocellular carcinoma with secondary abscessation in a catAUSTRALIAN VETERINARY JOURNAL, Issue 12 2005M SINGH A 16-year-old castrated male domestic shorthair cat was presented for investigation of weight loss, lethargy, inappetence and polydypsia. On serum biochemical analysis there was evidence of severe hepatocellular damage and cholestasis. Abdominal ultrasonographic examination revealed an irregular lesion of mixed echogenicity in a left hepatic lobe. It was compromised of a hypoechoic periphery surrounding an anechoic central area containing highly echogenic densities with distal acoustic shadowing suggestive of gas formation. On necropsy, the only gross abnormality was a solitary 5 cm×3 cm×3 cm multilobulated mass in the left lateral hepatic lobe, containing foul-smelling purulent fluid within a thick fibrous wall. Cytological examination of the fluid revealed numerous degenerate neutrophils and large numbers of Gram-positive sporeforming rods. The histopathological diagnosis was hepatocellular carcinoma with secondary abscessation. The bacterial morphology was consistent with Clostridia sp. Both hepatocellular carcinoma and focal hepatic abscessation are rare in cats. Hepatic abscesses should be included in the differential diagnosis of cats with non-specific signs, even in the absence of biochemical evidence of a hepatopathy. [source] Crystallization and preliminary crystallographic characterization of GumK, a membrane-associated glucuronosyltransferase from Xanthomonas campestris required for xanthan polysaccharide synthesisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2006Máximo Barreras GumK is a membrane-associated inverting glucuronosyltransferase that is part of the biosynthetic route of xanthan, an industrially important exopolysaccharide produced by Xanthomonas campestris. The enzyme catalyzes the fourth glycosylation step in the pentasaccharide-P-P-polyisoprenyl assembly, an oligosaccharide diphosphate lipid intermediate in xanthan biosynthesis. GumK has marginal homology to other glycosyltransferases (GTs). It belongs to the CAZy family GT 70, for which no structure is currently available, and indirect biochemical evidence suggests that it also belongs to the GT-B structural superfamily. Crystals of recombinant GumK from X. campestris have been grown that diffract to 1.9,Å resolution. Knowledge of the crystal structure of GumK will help in understanding xanthan biosynthesis and its regulation and will also allow a subsequent rational approach to enzyme design and engineering. The multiwavelength anomalous diffraction approach will be used to solve the phase problem. [source] Behavioural and biochemical evidence for interactions between ,9-tetrahydrocannabinol and nicotineBRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2002Emmanuel Valjent Behavioural and pharmacological effects of ,9-tetrahydrocannabinol (THC) and nicotine are well known. However, the possible interactions between these two drugs of abuse remain unclear in spite of the current association of cannabis and tobacco in humans. The present study was designed to analyse the consequences of nicotine administration on THC-induced acute behavioural and biochemical responses, tolerance and physical dependence. Nicotine strongly facilitated hypothermia, antinociception and hypolocomotion induced by the acute administration of THC. Furthermore, the co-administration of sub-threshold doses of THC and nicotine produced an anxiolytic-like response in the light,dark box and in the open-field test as well as a significant conditioned place preference. Animals co-treated with nicotine and THC displayed an attenuation in THC tolerance and an enhancement in the somatic expression of cannabinoid antagonist-precipitated THC withdrawal. THC and nicotine administration induced c-Fos expression in several brain structures. Co-administration of both compounds enhanced c-Fos expression in the shell of the nucleus accumbens, central and basolateral nucleus of the amygdala, dorso-lateral bed nucleus of the stria terminalis, cingular and piriform cortex, and paraventricular nucleus of the hypothalamus. These results clearly demonstrate the existence of a functional interaction between THC and nicotine. The facilitation of THC-induced acute pharmacological and biochemical responses, tolerance and physical dependence by nicotine could play an important role in the development of addictive processes. British Journal of Pharmacology (2002) 135, 564,578; doi:10.1038/sj.bjp.0704479 [source] Prolonged low-dose thrombolytic therapy: A novel adjunctive strategy in the management of an infected right atrial thrombusCLINICAL CARDIOLOGY, Issue 7 2002Sheila Chuang M.D. Abstract An 81-year-old man presented with a large, infected right atrial thrombus that was refractory to anticoagulants and several courses of antibiotics. The risk of surgical removal of the thrombus, which was associated with a pacemaker electrode, was considered prohibitive. The patient was treated for 7 days with low-dose (40 mg/day) tissue-type plasminogen activator (t-PA). Hemostatic monitoring during infusion revealed (1) aplasma t-PA antigen that was approximately 5% of that achieved during short-course t-PA for acute myocardial infarction, (2) biochemical evidence of prolonged clot lysis, and (3) no significant depletion of fibrinogen or plas-minogen. Nearly complete dissolution of the thrombus was observed. His bacteremia was eradicated by intravenous penicillin despite the presence of the pacemaker lead. This case highlights the benefits of combined antibiotic and thrombolytic therapy and documents for the first time the response of the human hemostatic system to prolonged t-PA infusion and the plasma t-PA levels attained when thrombolytic therapy is administered in this manner. Prolonged courses of fibrinolytic agents may be a good alternative to surgical intervention in selected patients with infected, right-sided intracardiac thrombi. [source] | |||||||||||||||||||||||||