Alterations in DNA methylation and genome structure in two rice mutant lines induced by high pressure

By using high-pressure treatment, two mutant lines were obtained from a genetically stable japonica rice cultivar Bijing38. Genomic DNA of the mutant lines, together with the original line (Bijing38), was either undigested or digested by Hpa II/Msp I, and then subjected to molecular analysis using two markers, ISSR and RAPD. Results indicated that changes in the PCR amplification profiles of both markers are apparent in the two mutant lines compared with the original rice cultivar, suggesting that there had been both sequence changes and DNA methylation modifications in the mutant lines. Southern blot analysis using diverse sequences, including two cellular genes (S2 and S3), a set of retrotransposons (Osr7, Osr36, Tos19 and more), and a MITE transposon family (mPing and Pong), confirmed the results, and indicated that changes in DNA methylation pattern, genomic structure, and possible activation of some transposons indeed occurred in the mutant lines. Moreover, these changes are stably maintained through selfed generations and in different organs. Thus, our results indicate that it is possible to obtain stable mutants in rice by high pressure treatments, and the molecular basis of the mutants may include both genetic and epigenetic changes. Therefore, high hydrostatic pressure seems a promising approach for plant mutagenesis.     

Inhibition of polyglutamine protein aggregation and cell death by novel peptides identified by phage display screening

Proteins with expanded polyglutamine domains cause eight inherited neurodegenerative diseases, including Huntington's, but the molecular mechanism(s) responsible for neuronal degeneration are not yet established. Expanded polyglutamine domain proteins possess properties that distinguish them from the same proteins with shorter glutamine repeats. Unlike proteins with short polyglutamine domains, proteins with expanded polyglutamine domains display unique protein interactions, form intracellular aggregates, and adopt a novel conformation that can be recognized by monoclonal antibodies. Any of these polyglutamine length-dependent properties could be responsible for the pathogenic effects of expanded polyglutamine proteins. To identify peptides that interfere with pathogenic polyglutamine interactions, we screened a combinatorial peptide library expressed on M13 phage pIII protein to identify peptides that preferentially bind pathologic-length polyglutamine domains. We identified six tryptophan-rich peptides that preferentially bind pathologic-length polyglutamine domain proteins. Polyglutamine-binding peptide 1 (QBP1) potently inhibits polyglutamine protein aggregation in an in vitro assay, while a scrambled sequence has no effect on aggregation. QBP1 and a tandem repeat of QBP1 also inhibit aggregation of polyglutamine-yellow fluorescent fusion protein in transfected COS-7 cells. Expression of QBP1 potently inhibits polyglutamine-induced cell death. Selective inhibition of pathologic interactions of expanded polyglutamine domains with themselves or other proteins may be a useful strategy for preventing disease onset or for slowing progression of the polyglutamine repeat diseases.     

Angiostatin's molecular mechanism: aspects of specificity and regulation elucidated

Tumor growth requires the development of new vessels that sprout from pre-existing normal vessels in a process known as "angiogenesis" [Folkman (1971) N Engl J Med 285:1182-1186]. These new vessels arise from local capillaries, arteries, and veins in response to the release of soluble growth factors from the tumor mass, enabling these tumors to grow beyond the diffusion-limited size of approximately 2 mm diameter. Angiostatin, a naturally occurring inhibitor of angiogenesis, was discovered based on its ability to block tumor growth in vivo by inhibiting the formation of new tumor blood vessels [O'Reilly et al. (1994a) Cold Spring Harb Symp Quant Biol 59:471-482]. Angiostatin is a proteolytically derived internal fragment of plasminogen and may contain various members of the five plasminogen "kringle" domains, depending on the exact sites of proteolysis. Different forms of angiostatin have measurably different activities, suggesting that much remains to be elucidated about angiostatin biology. A number of groups have sought to identify the native cell surface binding site(s) for angiostatin, resulting in at least five different binding sites proposed for angiostatin on the surface of endothelial cells (EC). This review will consider the data supporting all of the various reported angiostatin binding sites and will focus particular attention on the angiostatin binding protein identified by our group: F(1)F(O) ATP synthase. There have been several developments in the quest to elucidate the mechanism of action of angiostatin and the regulation of its receptor. The purpose of this review is to describe the highlights of research on the mechanism of action of angiostatin, its' interaction with ATP synthase on the EC surface, modulators of its activity, and issues that should be explored in future research related to angiostatin and other anti-angiogenic agents.     

Effects of nicotine and vitamin E on carbonic anhydrase activity in some rat tissues in vivo and in vitro

Effects of nicotine, nicotine + vitamin E and nicotine + Hippophea rhamnoides L. extract (HRe-1) on muscle, heart, lungs, testicle, kidney, stomach, brain and liver carbonic anhydrase (CA; EC 4.2.1.1.) enzyme activities were investigated in vivo. Groups of rats were given nicotine (0.5 mg/kg/day, i.p.), nicotine + vitamin E (75 mg/kg/day, i.g.), nicotine + HRe-1 (250 mg/kg/day, i.g.) and a control group vehicle only. The results showed that nicotine inhibited the heart, lung, stomach and liver CA enzyme activities by approximately 80% (p < 0.001), approximately 94% (p < 0.001), approximately 47% (p < 0.001) and approximately 81% (p < 0.001) respectively, and activated muscle and kidney, but had no effects on the testicle and brain CA activities. Nicotine + vitamin E inhibited the heart and liver CA enzyme activities by approximately 50% (p < 0.001), and approximately 50% (p < 0.001), respectively, and nicotine + vitamin E activated the muscle CA activity. However, nicotine + vitamin E had no effect on lung, testicle, kidney, stomach and brain CA activities. Nicotine + HRe-1 inhibited the heart and stomach CA enzyme activities by approximately 51% (p < 0.001), and approximately 32% (p < 0.002), respectively, and activated the muscle and brain CA activities, but had no effects on the lung, testicle, kidney, and liver CA activities. In vitro CA inhibition results for similar experiments correlated well with the in vivo experimental results in lungs, testicles, kidney, stomach, brain and liver tissues.     

The isolation and characterization of Campylobacter jejuni subsp. jejuni from domestic geese (Anser anser)

AIMS: The objectives of this study were to determine the presence of thermophilic Campylobacter spp. in free range domestic geese, and to characterize isolated strains using phenotyping criteria and SDS-PAGE of whole-cell proteins. METHODS AND RESULTS: Forty cloacal swabs from two different flocks of domestic geese were examined. All Camp. jejuni strains isolated from geese were biotyped using the Lior biotyping scheme. Twelve Camp. jejuni isolates were also tested for their susceptibility to 17 different antibacterial agents by a disc diffusion METHOD: Fourteen of the isolates were also subjected to SDS-PAGE. All of the geese examined were found to harbour Camp. jejuni. Six geese carried more than one species of Campylobacter. All strains examined were susceptible to various antibiotics but resistant to penicillin G and cephalothin. Eleven strains (92%) were resistant to sodium cefuroxime, and eight (67%) were resistant to cloxacillin, ampicillin and colistin sulphate. Three strains (25%) were resistant to tetracycline, and one strain was resistant to sulfamethoxazole/trimethoprim and kanamycin. Nine strains were subtyped as Camp. jejuni subsp. jejuni biotype II and the remaining ones as biotype I. There were 96% and 100% similarities between all the strains examined by SDS-PAGE. CONCLUSION: This study showed that Camp. jejuni were common in the intestinal tract of domestic geese. SIGNIFICANCE AND IMPACT OF THE STUDY: Geese should be considered as potential reservoirs for human and animal campylobacteriosis. The antibiotic resistance data from this study also showed that fluoroquinolone resistance, which appears to be a problem in poultry isolates in some countries, is not yet a problem in these geese.