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PubMed2000

Multiplex PCR for the identification of white Tuber species.

Species-specific primers selected from the internal transcribed spacer region sequence were used to set up a multiplex polymerase chain reaction (PCR) able to simultaneously identify the white truffle species Tuber magnatum, Tuber borchii, Tuber maculatum and Tuber puberulum. Furthermore, a primer specific for the competitive fungus Sphaerosporella brunnea was designed and added to the multiplex PCR set, allowing the detection of the Tuber species and the contaminant fungus in a one-step reaction.

Fungi↗
PubMed1994

Characterization of Monoclonal Antibodies Specific for Erwinia carotovora subsp. atroseptica and Comparison of Serological Methods for Its Sensitive Detection on Potato Tubers.

Seven monoclonal antibodies (MAbs) to Erwinia carotovora subsp. atroseptica have been produced. One, called 4G4, reacted with high specificity for serogroup I of E. carotovora subsp. atroseptica, the most common serogroup on potato tubers in different serological assays. Eighty-six strains belonging to different E. carotovora subsp. atroseptica serogroups were assayed. Some strains of serogroup XXII also reacted positively. No cross-reactions were observed against other species of plant pathogenic bacteria or 162 saprophytic bacteria from potato tubers. Only one strain of E. chrysanthemi from potato cross-reacted. A comparison of several serological techniques to detect E. carotovora subsp. atroseptica on potato tubers was performed with MAb 4G4 or polyclonal antibodies. The organism was extracted directly from potato peels of artificially inoculated tubers by soaking or selective enrichment under anaerobiosis in a medium with polypectate. MAb 4G4 was able to detect specifically 240 E. carotovora subsp. atroseptica cells per ml by indirect immunofluorescence and immunofluorescence colony staining and after soaking by ELISA-DAS (double-antibody sandwich enzyme-linked immunosorbent assay) after enrichment. The same amount of cells was detected by using immunolectrotransfer with polyclonal antibodies, and E. carotovora subsp. atroseptica and subsp. carotovora were distinguished by the latter technique. ELISA-DAS using MAb 4G4 with an enrichment step also efficiently detected E. carotovora subsp. atroseptica in naturally infected tubers and plants.

Journal Article↗
PubMed1999

Analgesia-producing mechanism of processed Aconiti tuber: role of dynorphin, an endogenous kappa-opioid ligand, in the rodent spinal cord.

The analgesia-producing mechanism of processed Aconiti tuber was examined using rodents whose nociceptive threshold was decreased by loading repeated cold stress (RCS). The antinociceptive effect of processed Aconiti tuber (0.3 g/kg, p.o.) in RCS-loaded mice was antagonized by pretreatment with a kappa-opioid antagonist, nor-binaltorphimine (10 mg/kg, s.c.), and was abolished by an intrathecal injection of anti-dynorphin antiserum (5 microg). The Aconiti tuber-induced antinociception was inhibited by both dexamethasone (0.4 mg/kg, i.p.) and a dopamine D2 antagonist, sulpiride (10 mg/kg, i.p.), in RCS-loaded mice, and it was eliminated by both an electric lesion of the hypothalamic arcuate nucleus (HARN) and a highly selective dopamine D2 antagonist, eticlopride (0.05 microg), administered into the HARN in RCS-loaded rats. These results suggest that the analgesic effect of processed Aconiti tuber was produced via the stimulation of kappa-opioid receptors by dynorphin released in the spinal cord. It was also shown that dopamine D2 receptors in the HARN were involved in the expression of the analgesic activity of processed Aconiti tuber.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed2003

Induction mechanism of 3-hydroxy-3-methylglutaryl-CoA reductase in potato tuber and sweet potato root tissues.

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR, EC1.1.1.34), the key enzyme in isoprenoid biosynthesis, was purified from microsomes of potato tuber tissue, and a polyclonal antibody and two monoclonal antibodies against the purified enzyme were prepared. HMGR protein content was measured by immunotitration and radioimmunoassay using these antibodies. HMGR activity was very low in the fresh tissues of both potato tuber and sweet potato root. The activity in potato tuber was increased by cutting and further by additional fungal infection of the cut tissues. In sweet potato root tissue, the activity was scarcely increased after cutting alone, but was markedly increased by additional fungal infection or chemical treatment. The HMGR protein contents in both fresh potato tuber and sweet potato root tissues were also very low, and increased markedly in response to cutting and fungal infection. From these results, we proposed a hypothesis on the induction mechanism of HMGR after cutting and fungal infection in potato tuber and sweet potato root tissues.

Animals↗
PubMed2000

[Evaluation of the possible technological uses of some dioscoreas tubers: name congo (Dioscorea bulbifera) and mapuey (Dioscorea trifida)].

A comparison between the chemical composition and physical characteristics of ñame congo (Dioscorea bulbifera) and mapuey (Dioscorea trifida) white and purple varieties, was made. The tubers were evaluated for their physical attributes (morphology, size and weight). The chemical analysis was done according to AOAC methods (1990) and the pasting properties of the flours were evaluated using the Brabender Viscoamilograph. The mapuey tubers have an elongated shape, with one end wider while ñame congo presents a rounded shape. The results of the chemical analysis show that mapuey tubers have more proteins content (p < or = 0.05) than either purple mapuey tubers purple or ñame congo tubers. The flours overall viscosity, measured at the same concentration, was higher for white mapuey varieties. The gelatinization temperature range was similar among the flours. The negative breakdown datas suggest that the flours viscosity increases during the gelatinization process of all flours. Neither suspensions showed a viscosity peak. Set-back and consistency were lower in the ñame congo flour. The absence of a viscosity peak and the high temperature stability of the ñame congo flour make it an ideal ingredient for instant soup mixes. The flours high viscosity level developed by white and purple mapuey varieties should make it a suitable sauces thickener.

Flour↗
PubMed2005

Nutritional properties of tubers of conventionally bred and transgenic lines of potato resistant to necrotic strain of Potato virus Y (PVYN).

The potential effect of genetic modification on nutritional properties of potatoes transformed to improve resistance to a necrotic strain of Potato virus Y was determined in a rat experiment. Autoclaved tubers from four transgenic lines were included to a diet in the amount of 40% and compared with the conventional cv. Irga. The experiment lasted 3 weeks and special attention was paid to nutritional properties of diets, caecal metabolism and serum indices. Genetic modification of potato had no negative effect on the chemical composition and nutritional properties of tubers, ecosystem of the caecum, activity of serum enzymes and non-specific defence mechanism of the rats. Obtained results indicate that transgenic potato with improved resistance to PVY(N): line R1F (truncated gene coding for PVY(N) polymerase in sense orientation), R2P (truncated gene coding for PVY(N) polymerase in antisense orientation), and NTR1.16 (non-translated regions of PVY(N) genome in sense orientation) are substantial and nutritional equivalence to the non-transgenic cultivar. Tubers of transgenic line NTR2.27 (non-translated regions of PVY(N) genome in antisense orientation) increased the bulk of caecal digesta and the production of SCFA as compared to tubers of the conventional cultivar and the other transgenic clones. Taking into account some deviations, it seems reasonable to undertake a long-term feeding study to confirm the nutritional properties of tubers of transgenic lines.

Animals↗
PubMed1993

Expression of the potato tuber ADP-glucose pyrophosphorylase in Escherichia coli.

cDNA clones encoding the putative mature forms of the large and small subunits of the potato tuber ADP-glucose pyrophosphorylase have been expressed separately and together in an Escherichia coli B mutant deficient in ADP-glucose pyrophosphorylase activity. Expression of both subunits from compatible vectors resulted in restoration of ADP-glucose pyrophosphorylase activity. Maximal enzyme activity required both subunits. The expressed ADP-glucose pyrophosphorylase was purified and characterized. The recombinant enzyme exhibited catalytic and allosteric kinetic properties very similar to the enzyme purified from potato tuber. The expressed enzyme activity was neutralized by incubation with antibodies raised against potato tuber and spinach leaf ADP-glucose pyrophosphorylases but not with anti-Escherichia coli enzyme serum. 3-Phosphoglycerate was the most efficient activator and its effect was increased by dithiothreitol. In the ADP-glucose synthesis direction, 3-phosphoglycerate activated the recombinant enzyme nearly 100-fold in the presence of dithiothreitol, with an A0.5 value of 57 microM. The recombinant ADP-glucose pyrophosphorylase was less sensitive to P(i) inhibition and more sensitive to heat denaturation than the potato tuber enzyme. Results suggest that bacterial expression of potato tuber cDNAs could be used to study the role and interaction of the subunits of the native ADP-glucose pyrophosphorylase.

Allosteric Regulation↗
PubMed1996

Loss of tuberin from cerebral tissues with tuberous sclerosis and astrocytoma.

We studied the expression of tuberin, the TSC2 gene product, in cerebra with or without tuberous sclerosis. Tuberin was abundant in the gray matter of normal cerebra, but was undetectable in the subependymal astrocytomas from 3 patients with tuberous sclerosis. In 1 patient, cortical tubers and normally appearing cortical tissue also showed a marked loss of tuberin. These results indicate the critical role of tuberin in the neuropathology of tuberous sclerosis.

Adolescent↗
PubMed2004

Tuberous sclerosis and polycystic kidney disease in a 3-month-old infant.

Tuberous sclerosis (TSC) is an autosomal dominantly inherited multisystemic disease characterized by the development of hamartomas predominantly in brain and kidneys. The TSC2 gene for tuberous sclerosis is localized on chromosome 16p13.3 immediately adjacent to PKD1, the gene for autosomal dominant polycystic kidney disease (ADPKD). A TSC2-PKD1 contiguous gene syndrome caused by chromosomal microdeletions disrupting both the TSC2 and PKD1 genes has been identified in patients with TSC and early-onset severe ADPKD. We report a 3-month-old Caucasian girl of non-consanguineous parents with TSC and early manifestation of ADPKD. She presented with right-sided focal seizures, two small hypopigmented areas on the left flank, and elevated blood pressure requiring antihypertensive treatment. Brain magnetic resonance imaging revealed typical signs of tuberous sclerosis and abdominal ultrasonography showed bilaterally enlarged kidneys with multiple cysts resembling those seen in ADPKD. There was no family history of renal disease or of tuberous sclerosis. Findings were highly suspicious of TSC2-PKD1 contiguous gene syndrome. Using fluorescence in situ hybridization and plasmid probe CW23, which spans the adjacent 3' regions of TSC2 and PKD1 genes, we identified a submicroscopic deletion on only one of the chromosomes 16p13.3, thus permitting the diagnosis of the TSC2-PKD1 contiguous gene syndrome.

Brain↗
PubMed2003

Regulation of PCNA and CAF-1 expression by the two tuberous sclerosis gene products.

Tuberous sclerosis is an autosomal dominant tumor suppressor gene syndrome affecting about 1 in 6000 individuals. Two genes have been shown to be responsible for this disease: TSC1, encoding hamartin and TSC, encoding tuberin. A variety of tumors characteristically occur in different organs of tuberous sclerosis patients and are believed to result from defects in cell cycle/cell size control. In this study, we performed two-dimensional gel electrophoresis with subsequent mass spectrometrical identification of protein spots after overexpression of TSC1 or TSC2. We found expression of PCNA and the p48 subunit of CAF-1 to be regulated by two tuberous sclerosis gene products. CAF-1 and PCNA interact as major regulators of chromatin assembly during DNA repair. We suggest that deregulation of the control of chromatin assembly might contribute to development of tumors in tuberous sclerosis patients and provide important new insights into the molecular development, especially since deregulation of chromatin assembly and DNA repair results in genomic instability, a hallmark of tumor development.

Chromatin Assembly Factor-1↗
PubMed1998

A mutation screen of the TSC1 gene reveals 26 protein truncating mutations and 1 splice site mutation in a panel of 79 tuberous sclerosis patients.

The entire coding region of the TSC1 gene has been screened for mutations in 79 unrelated patients with tuberous sclerosis. Causative mutations have been found in 27 of these patients and five other variations in the gene have been identified. 26 of the mutations are predicted to cause premature truncation of the protein product of the gene and one mutation is in a splice site. The mutation screen has revealed that TSC1 mutations are rarer in sporadic tuberous sclerosis patients than in familial cases. We have also found that the only previously described case of non-penetrance can no longer be described as such, and that a single ungual fibroma is not necessarily diagnostic of tuberous sclerosis, important findings for the genetic counselling of tuberous sclerosis patients.

Blotting, Southern↗
PubMed2004

Abnormal cortical cells and astrocytomas in the Eker rat model of tuberous sclerosis complex.

PURPOSE: In patients with tuberous sclerosis complex (TSC), a wide range of neurologic abnormalities develop, including mental retardation and seizures. Brains from TSC patients are characterized by the presence of cortical tubers, large dysmorphic neurons, and abnormal cytomegalic cells. Although analysis of human TSC brain samples led to the identification of these abnormal cell types, very little is known about how these cells function. In an effort to model TSC-associated CNS abnormalities (and ultimately to analyze the electrophysiologic properties of abnormal cells), we examined Eker rats carrying a Tsc2 mutation. Anatomic studies, including standard histologic stains and immunocytochemistry, were performed on young Eker rats exposed to a carcinogen in utero or aged untreated Eker rats (18-24 months old). METHODS: Pregnant TSC2+/- females were injected once a day with hydroquinone (HQ), and offspring were killed at postnatal day P14 or P28. Coronal tissue sections throughout the CNS were prepared and stained for cresyl violet. In separate studies, brains of old untreated Eker rats were sectioned for anatomic analysis by using standard immunohistochemical techniques. RESULTS: Tissue sections stained with cresyl violet did not reveal any gross differences between HQ-treated Eker (Tsc2Ek/+) rats and siblings (Tsc2+/+). However, two classes of abnormal giant cells were observed in brain sections from untreated aged Eker rats: (a) large dysmorphic pyramid-like cells immunoreactive for NeuN, tuberin, and EAAC-1 in layers IV-VI; and (b) abnormal cytomegalic cells immunoreactive for glial fibrillary acidic protein (GFAP), vimentin, and nestin in deep cortical layers or along the white matter. In addition, large subependymal astrocytomas were observed in four animals. CONCLUSIONS: Our data suggest that cortical tuber formation in Eker rats is a rare event and that prenatal exposure to a nongenotoxic carcinogen such as HQ is not sufficient to induce tuber formation. However, with advanced age, an increased likelihood of astrocytoma formation and the emergence of dysmorphic neurons and cytomegalic cells in the Eker rat brain might exist; each of these abnormalities mimics those seen clinically and could contribute to neurologic problems associated with TSC. Further analysis of this rodent model may be warranted.

Animals↗
PubMed2005

Developmental origin of subependymal giant cell astrocytoma in tuberous sclerosis complex.

Children with tuberous sclerosis complex (TSC) harbor developmental brain abnormalities (cortical tubers) and low-grade tumors (subependymal giant cell astrocytomas [SEGAs]). Using gene expression profiling to identify neuroglial differentiation markers in Tsc1 conditional knockout mice, the authors demonstrate that giant cells of SEGAs aberrantly express similar neuroglial differentiation markers as do cortical tubers. These results suggest that both tubers and SEGAs result from related defects in progenitor cell differentiation during brain development.

Adolescent↗
PubMed1987

Magnetic resonance imaging in tuberous sclerosis.

Twenty-five patients with tuberous sclerosis were studied with magnetic resonance imaging (MRI), and these findings were compared with those of computed cranial tomography (CCT) and with the clinical severity of the disease. Multiple high-signal MRI lesions involving the cerebral cortex are characteristic of tuberous sclerosis and probably correspond to the hamartomas and gliotic areas seen pathologically. These cortical lesions were only occasionally seen with CCT. The periventricular calcific lesions characteristic of tuberous sclerosis are better visualized with CCT than with MRI, but the larger periventricular calcifications produce low-signal MRI abnormalities. Seven patients had high-signal MRI lesions of the cerebellum; small calcific cerebellar lesions were also noted with CCT in three patients. As in earlier studies, no clear correlation was seen between the number of abnormalities visible with CCT and the clinical severity of the disease. By contrast, the more severely affected patients tend to have a higher number of cerebral cortical lesions detected with MRI. Thus, MRI may be useful in predicting the eventual clinical severity of younger children with newly diagnosed tuberous sclerosis.

Adolescent↗
PubMed2000

Hamartomas of the iris and ciliary epithelium in tuberous sclerosis complex.

Astrocytic hamartomas of the retina are the principal ocular manifestation of tuberous sclerosis complex. Iris abnormalities are rare in tuberous sclerosis complex and include focal areas of stromal depigmentation and atypical colobomata. We describe 2 patients who were found on histopathological examination to have lesions consistent with hamartomas of the iris pigment epithelium and ciliary body epithelium. Iris abnormalities, including pupillary irregularities, were noted on clinical examination prior to the development of iris neovascularization in both patients. These observations suggest that iris abnormalities, including atypical colobomas, may be caused by hamartomas of the iris pigment epithelium and ciliary epithelium in some patients with tuberous sclerosis complex. To our knowledge, hamartomas of tissues derived from the anterior part of the neuroectodermal optic cup have not been reported in cases of tuberous sclerosis complex.

Child, Preschool↗
PubMed2003

Analysis of protein profiles of genetically modified potato tubers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Traceability of genetically modified (GM) foods demands the development of appropriate reliable techniques in order to identify and quantify peptide or nucleic acid residues in GM plants and food products through the food chain. In this study the applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was demonstrated for the characterization of proteins of transformed and untransformed potato (Solanum Tuberosum L.) tubers. In GM tubers the expression level of the G1-1 gene, which regulates transition from dormancy to sprouting tubers, was inhibited by antisense technology. The analysis of antisense transformed lines showed that several of them exhibited a significant delay in sprouting relative to the control lines, in accordance with a decrease in the transcript level. Preliminary attempts to compare the protein patterns obtained from transformed and control lines using traditional electrophoresis were not able to reveal differences in the low-kDa range. Instead, MALDI-TOFMS applied to total peptide extract without any purification was able to distinguish spectral patterns of transformed and untransformed lines. In particular, several characteristic peaks from m/z 4373 to 4932 were detected only in the mass spectra of GM tuber samples.

Food, Genetically Modified↗
PubMed1995

The loss of 40-kDa chromosomal protein in tuberous sclerosis lesions.

Tuberous sclerosis is an genetic disease characterized by systemic hamartomas. Some of the cultured cells derived from tuberous sclerosis show the distinct chromosomal disarrangement and abnormal cell division. To detect the proteins responsible for this phenomenon, we investigated many nuclear components related to cell division. 40-kDa protein (p40) recognized by one monoclonal antibody M108, which was present in nucleus, chromosomes and cytoplasm of many vertebrate culture cells, significantly decreased in the tuberous sclerosis cells. Immunoblot analysis revealed that in all the fractions the quantity of p40 of severe tuberous sclerosis cells was approximately 4 times less than p40 in normal fibroblasts.

Antibodies, Monoclonal↗
PubMed1984

Coarctation of the aorta and renal artery stenosis in tuberous sclerosis.

Among neurocutaneous disorders, coarctation of the abdominal aorta and renal artery stenosis have traditionally been associated with neurofibromatosis. We report a 5-year-old girl who, during the evaluation of asymptomatic hypertension, was discovered to have bilateral renal artery stenosis, coarctation of the abdominal aorta, renal cysts and typical skin lesions of tuberous sclerosis. Renal vascular hypertension has not been reported previously in tuberous sclerosis. We conclude that the tuberous sclerosis complex should be expanded to include vascular malformations and that hypertension should not be assumed to be secondary to renal hamartomata or cysts in patients with tuberous sclerosis.

Aortic Coarctation↗