H1° and H3.3B mRNA levels in developing rat brain

Two overlapping rat cDNAs, covering a continuous region of 1107 base pairs, have been isolated and sequenced. The clones contain identical open reading frames, encoding a 136 amino acid long polypeptide which exhibits 100% identity to other mammalian H3.3 histone variants. We show that the inserts derive, in particular, from the H3.3B gene. We used these inserts and an insert from an H1° encoding clone, previously described (6), as probes to study the accumulation of mRNAs encoding the corresponding histone replacement variants (namely, H1° and H3.3) during rat brain development. We found that the concentration of both H1° and H3.3B mRNAs decreases from the embryonal day 18 (E18) to the postnatal day 10 (P10), with inverse correlation to protein accumulation.This paper is dedicated to our friend Paolo Carbone who devoted his life to research and teaching in Genetics. We will always remember him for scientific honesty and for his unique qualities of humanity.     

Coccoid Helicobacter pylori Not Culturable In Vitro Reverts in Mice

An experimental rodent model was used to demonstrate the viability of the coccoid form of Helicobacter pylori. Concentrated suspensions were prepared for the two different morphologies: at 2 days incubation for the bacillary forms and at 20 days incubation for the “dormant” forms. The strains used for incubation were two fresh isolates from humans with duodenal ulceration, and two collection strains. Five hundred microliters of culture (OD₅₅₀ = 5 Mc Farland) of Helicobacter pylori with bacillary (2-5×10⁹ CFU/ml) and coccoid (0 CFU/ml) morphology were inoculated intragastrically in BALB/c mice. The gastric mucosa of the mice was colonized by Helicobacter pylori with the administration of fresh bacillary and coccoid cultures and not with the established cultures. Helicobacter pylori was isolated at 1 week after inoculation with the administration of fresh bacillary cultures, while fresh coccoid Helicobacter pylori was recovered in mice stomachs after 2 weeks of inoculation. After colonization, histopathologic changes occurred after 1 month from inoculation; all colonized mice showed a systemic antibody response to Helicobacter pylori. These results support the thesis of the viability of coccoid Helicobacter pylori non-culturable in vitro and confirm that concentrated bacterial suspensions are able to colonize and to produce gastric alterations in this suitable animal model.     

Campodimele Study: Blood Pressure and Heart Rate Pattern in Clinically Healthy Elderly Subjects

Noninvasive ambulatory blood pressure (BP) monitoring is a developing method in clinical practice. Its interpretation needs reference standards stratified by age and gender. This study addresses ambulatory BP monitoring in elderly people with the purpose of quantifying the discrete and periodic variability of BP pattern over a 24-h period. The ABPM was performed in 92 clinically healthy subjects (45 men and 47 women) ranging in age from 76 to 102 years. The results refer to the time-qualified mean values with their dispersion, to the circadian rhythm with its parameters, and to the daily baric impact (BI) with its variability. The conclusion is drawn that BP preserves its nychtohemeral variability and circadian rhythmicity despite old age. The daily BP mean level and BI in older people in good health are comparable with those of young subjects, suggesting that humans surviving into old age are characterized by a eugenic control of their pressure regimen.     

大血藤科植物的分类学研究

作者对大血藤科植物的花性、叶片内部结构形态、花粉形态、染色体核型及过氧化物酶和脂酶同工酶进行了比较研究,结果表明：１）大血藤科植物外形上的两性花,其雄蕊的形态退化、花药始终不开裂,为功能上的雌花,因此其花为单性,同株,同序或异序;１２）首次指出大血藤属植物的染色体数为２ｎ＝２ｘ＝２２,属小型染色体,与木通科植物２ｎ＝２ｘ＝３２、３０、２８的染色体数明显不同,支持Ｓｔａｐｆ（１９２６）将其从木通科分出另立为科的观点;３）单叶和复叶可出现于同一植株上,而且在叶片内部结构、花粉形态、染色体核型、过氧化物酶及脂酶同工酶等性状上,大血藤与单叶血滕间均无实质性的差异,因此将单叶血藤归并于大血藤中。     

Toxicity of and mutagenesis by chlorate are independent of nitrate reductase activity in Chlamydomonas reinhardtii

Summary Spontaneous chlorate-resistant (CR) mutants have been isolated from Chlamydomonas reinhardtii wildtype strains. Most of them, 244, were able to grow on nitrate minimal medium, but 23 were not. Genetic and in vivo complementation analyses of this latter group of mutants indicated that they were defective either at the regulatory locus nit-2, or at the nitrate reductase (NR) locus nit-1, or at very closely linked loci. Some of these nit-1 or nit-2 mutants were also defective in pathways not directly related to nitrate assimilation, such as those of amino acids and purines. Chlorate treatment of wild-type cells resulted in both a decrease in cell survival and an increase in mutant cells resistant to a number of different chemicals (chlorate, methylammonium, sulphanilamide, arsenate, and streptomycin). The toxic and mutagenic effects of chlorate in minimal medium were not found when cells were grown either in darkness or in the presence of ammonium, conditions under which nitrate uptake is drastically inhibited. Chlorate was also able to induce reversion of nit ^– mutants of C. reinhardtii, but failed to produce His ⁺ revertants or Ara^r mutants in the BA-13 strain of Salmonella typhimurium. In contrast, chlorate treatment induced mutagenesis in strain E1F1 of the phototrophic bacterium Rhodobacter capsulatus. Genetic analyses of nitrate reductase-deficient CR mutants of C. reinhardtii revealed two types of CR, to low (1.5 mM) and high (15 mM) chlorate concentrations. These two traits were recessive in heterozygous diploids and segregated in genetic crosses independently of each other and of the nit-1 and nit-2 loci. Three her loci and four lcr loci mediating resistance to high (HC) and low (LC) concentrations of chlorate were identified. Mutations at the nit-2 locus, and deletions of a putative locus for nitrate transport were always epistatic to mutations responsible for resistance to either LC or HC. In both nit ⁺ and nit ^– chlorate-sensitive (CS) strains, nitrate and nitrite gave protection from the toxic effect of chlorate. Our data indicate that in C. reinhardtii chlorate toxicity is primarily dependent on the nitrate transport system and independent of the existence of an active NR enzyme. At least seven loci unrelated to the nitrate assimilation pathway and mediating CR are thought to control indirectly the efficiency of the nitrate transporter for chlorate transport. In addition, chlorate appears to be a mutagen capable of inducing a wide range of mutations unrelated to the nitrate assimilation pathway.     

Angiotensin II Type 1 Receptor mRNA Levels in the Brains of Normotensive and Spontaneously Hypertensive Rats

Abstract: The type 1 angiotensin II (All) receptor (AT₁-R) has been implicated in the physiological actions mediated by All in the brain. In view of the reported hyperactivity of the brain All system in the spontaneously hypertensive rat (SHR), we compared the expression of AT,-R mRNAs in the brains of normotensive [Wistar Kyoto (WKY)] and SHR animals. Northern blot analysis showed about three- and ∼20-fold increases in the levels of AT₁-R mRNAs from the hypothalamus and brainstem areas, respectively, of the SHR compared with the WKY rat brain. This was attributable to greater levels of both AT,_1A- and AT,_1B-R mRNA subtypes in these areas from the SHR. These observations suggest that increased All receptor levels in SHR brain may, in part, be a result of increased expression of the AT₁-R gene.