Tumor formation in hybrids between Solanum lycopersicum and S. habrochaites

Genetic tumors are neoplastic growths that arise spontaneously in particular genotypes in plants. In the present study, we observed the occurrence of tumors in interspecific hybrids between Solanum lycopersicum L. and Solanum habrochaites S. Knapp and D. M. Spooner. The hybridity of these plants was confirmed based on morphological characteristics, flow cytometry and random amplified polymorphic DNA analysis. Hybrids formed tumors when the plants were grown in a growth chamber. These tumors were formed most frequently on leaves, but also on cotyledons, stems and petioles. When hybrid plants bearing tumors were transferred to a greenhouse, the tumors disappeared and necrotic brown spots were visible in the positions where tumors existed previously. Further analyses indicated that tumors were never formed in the greenhouse. These results suggest that environmental conditions influenced tumorigenesis in hybrids raised from S. lycopersicum × S. habrochaites crosses. In addition, when stem segments of hybrids were cultured in vitro on plant growth regulator-free medium, tumors and shoot formation were induced. Thus, hybrids between S. lycopersicum × S. habrochaites provide an excellent experimental system to study plant tumorigenesis and to understand cell division and differentiation.Keywords: Environmental condition, growth abnormality, interspecific cross, tomato, tissue culture, tumorAfrican Journal of Biotechnology Vol. 12(15), pp. 1745-175

Gymnemic acids inhibit rabbit glyceraldehyde-3-phosphate dehydrogenase and induce a smearing of its electrophoretic band and dephosphorylation

AbstractGymnemic acids (GA) inhibited rabbit muscle glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. Binding of GA to GAPDH was observed by surface plasmon resonance measurement. Incubation of GAPDH with GA induced a smearing of the GAPDH band in SDS–PAGE. The GA-induced smearing was diminished by prior incubation of GA with γ-cyclodextrin or by GA treatment with NAD. GA treatment did not affect the electrophoretic mobility of glucose-6-phosphate isomerase and dehydrogenase. GA treatment diminished the GAPDH band detected by an antibody to phosphoserine, but did not affect the phosphoserine bands of glucose-6-phosphate isomerase and dehydrogenase. These results indicated that GA specifically induced dephosphorylation of GAPDH

Extensively Hydrated but Folded: A Novel State of Globular Proteins Stabilized at High Pressure and Low Temperature

AbstractWe studied conformational fluctuations of the transcription factor c-Myb R2 subdomain (52 residues with three Trp) at high pressure and low temperature (5°C) using two different spectroscopic methods, Trp fluorescence and 1H NMR, on its chemically stable mutant C130I (pseudo-wild-type (WTS)), which has a large internal cavity. As pressure was increased from 3 to 300 MPa, the Trp fluorescence λmax of WTS shifted from 342 to ∼355 nm, clearly showing that the three Trp rings become fully exposed to the polar environment, which usually is taken to indicate that the protein underwent unfolding. In contrast, as pressure was increased from 3 to 300 MPa, the high-field-shifted 1H NMR signals characteristic of the folded state showed a still higher-field shift, but no significant changes in their intensity. The last result unequivocally shows that the protein remains largely folded at 300 MPa. The apparent discrepancy between the two predictions would only be solved if one were to postulate the existence of an extensively hydrated but folded state in WTS. Intriguingly, such a state was not found in a cavity-filling mutant of WTS, C130I/V103L, suggesting that this state is mediated by cavity hydration. The generality and significance of this state in proteins are discussed

STM/STS study on electronic superstructures in the superconducting state of high-T-c cuprate Bi2Sr2CaCu2O8+delta

We report STM/STS measurements at 8 K in underdoped Bi2Sr2CaCu2O8+delta crystals (T-c = 76 K and hole-doping level p similar to 0.12) whose energy spectra around the Fermi level are characterized by a two-gap structure consisting of spatially inhomogeneous pseudogap (PG) and comparatively homogeneous superconducting gap (SCG). Two electronic superstructures, checkerboard modulation (CBM) and Cu-O-Cu bond-centered modulation (BCM), are observed with mapping spectral weights at low energies within the SCG and the ratio of spectral weights at +/-Delta(PG) (PG energy), respectively. On the basis of the present findings, we suggest that the lower-energy scale CBM is an intrinsic property of Cu-O planes and can coexist with the BCM whose characteristic energy is similar to Delta(PG) in identical regions in real space

Strict De Novo Methylation of the 35S Enhancer Sequence in Gentian

A novel transgene silencing phenomenon was found in the ornamental plant, gentian (Gentiana triflora × G. scabra), in which the introduced Cauliflower mosaic virus (CaMV) 35S promoter region was strictly methylated, irrespective of the transgene copy number and integrated loci. Transgenic tobacco having the same vector did not show the silencing behavior. Not only unmodified, but also modified 35S promoters containing a 35S enhancer sequence were found to be highly methylated in the single copy transgenic gentian lines. The 35S core promoter (−90)-introduced transgenic lines showed a small degree of methylation, implying that the 35S enhancer sequence was involved in the methylation machinery. The rigorous silencing phenomenon enabled us to analyze methylation in a number of the transgenic lines in parallel, which led to the discovery of a consensus target region for de novo methylation, which comprised an asymmetric cytosine (CpHpH; H is A, C or T) sequence. Consequently, distinct footprints of de novo methylation were detected in each (modified) 35S promoter sequence, and the enhancer region (−148 to −85) was identified as a crucial target for de novo methylation. Electrophoretic mobility shift assay (EMSA) showed that complexes formed in gentian nuclear extract with the −149 to −124 and −107 to −83 region probes were distinct from those of tobacco nuclear extracts, suggesting that the complexes might contribute to de novo methylation. Our results provide insights into the phenomenon of sequence- and species- specific gene silencing in higher plants

A Case of Streptobacillus moniliformis Infection with Cutaneous Leukocytoclastic Vasculitis

A 71-year-old man presented with a high fever, polyarthralgia, petechiae and palpable purpura accompanied by livedoid change on his legs and feet. Histopathological findings of the purpura revealed perivascular infiltration of neutrophils, mononuclear cells, and nuclear debris, and extravasation of red cells mainly in the upper dermis: all signs consistent with leukocytoclastic vasculitis. Small vessel thrombi, which are characteristic features of septic vasculopathy, were also observed. Direct immunofluorescence showed negative results. Blood culture revealed the growth of gram-negative bacilli. Subsequently, 16S rRNA sequencing of DNA confirmed the organism as Streptobacillus moniliformis, which is the causative pathogen of rat-bite fever. He had frequently encountered wild rats in his house although there was no evidence of rat bite on his body. Empiric therapy with intravenous administration of ceftriaxone in combination with azithromycin hydrate led to a prompt resolution of the symptoms. Precise history-taking related to contact with rats and detection of skin eruptions suggestive of leukocytoclastic vasculitis on the extremities, especially on the feet, can be clues to Streptobacillus moniliformis infection. Familiarity with its cutaneous features is important for early diagnosis; the evidence herein may also help in understanding its underlying pathogenesis

Role of Gremlins in the Aortic Arch of Spontaneously Hypertensive and Hyperlipidemic Rats

Atherosclerosis is a lifestyle-related disease that plays a major role in cardiovascular disease. Recently, we found that gene expression of Gremlin 2, an antagonist of bone morphogenetic protein (BMP), was significantly increased in the aorta of spontaneously hypertensive and hyperlipidemic rats (SHHRs) fed a high-fat, 30% sucrose solution diet (HFDS). However, the role of Gremlin 1 (Grem1) and Gremlin 2 (Grem2) in the aortic arch of rats under hypertensive, hyperlipidemic, and hyperglycemic conditions remains unclear. Therefore, in the present study we investigated the molecular role of Gremlins in the aorta of SHHRs. Four-month-old male Sprague-Dawley rats and SHHRs were fed a normal diet or the HFDS ad libitum for 4 months. Then, gene and protein expression was analyzed using quantitative polymerase chain reaction and western blotting, respectively. Grem1 and Grem2 protein expression was increased, whereas phosphorylated Smad1/5 protein expression was low, in the aorta of SHHRs fed the HFDS. In addition, the expression of the downstream gene targets of BMP, namely inhibitor of DNA binding 1 (Id1) and atonal homolog 8 (Atoh8), was decreased in aortas of SHHRs fed the HFDS. Furthermore, mRNA expression of Snail, α-smooth muscle actin (αSMA), and Fibronectin was increased in SHHRs fed the HFDS. These findings suggest that upregulation of Gremlins attenuates the activation of BMP signaling, which contributes to fibrogenesis of the aorta

Effects of arterial carbon dioxide manipulation on cerebral oxidative metabolism during hemorrhagic hypotension in dogs

[Background] : Development of brain acidosis is concerned during prolonged hemor- rhagic hypotension due to blood-brain barrier disruption, even though cerebral blood flow is maintained. There is possibility that PaC02 manipulation affects brain acidosis induced deterioration of cerebral oxidative metabolism by influencing the brain acid- base equilibrium. [Methods] : A dog model of hemorrhagic hypotension was used. Mean arterial pressure was kept at the lower limit of autoregulation to assure maintained cerebral blood flow. One of three different PaC02 manipulations, hypocapnia, normocapnia or hy-percapnia, was applied during hypotension and the effect of PaC02 manipulations on cerebral oxidative metabolism was estimated. [Results] : Cerebral blood flow and cerebral metabolic rate for oxygen remained unal-tered during hypotension. Brain acidosis was developed regardless of the PaC02 ma-nipulation used, being most acidotic with hypercapnia. Hypercapnia was accompanied by a significant decrease in phosphocreatinine and an increase in the L/P ratio com-pared to hypocapnia and normocapnia. [Conclusions] : PaC02 manipulation differentially affects cerebral oxidative metabolism during hemorrhagic hypotension with preserved cerebral blood flow, being worse with hypercapnia