The enzymic composition of the isolated cell wall and plasma membrane of baker''s yeast

A study was made of the enzyme content of the isolated cell walls and of a plasma-membrane preparation obtained by centrifugation after enzymic digestion of the cell walls of baker's yeast. The isolated cell walls showed no hexokinase, alkaline phosphatase, esterase or NADH oxidase activity. It was concluded that these enzymes exist only in the interior of the cell. Further, only a negligible activity of deamidase was detectable in the cell walls. Noticeable amounts of saccharase, phosphatases hydrolysing p-nitrophenyl phosphate, ATP, ADP, thiamin pyrophosphate and PP(i), with optimum activity at pH3-4, and an activity of Mg(2+)-dependent adenosine triphosphatase at neutral pH, were found in the isolated cell walls. During enzymic digestion, the other activities appearing in the cell walls were mostly released into the medium, but the bulk of the Mg(2+)-dependent adenosine triphosphatase remained in the plasma-membrane preparation. Accordingly, it may be assumed that the enzymes released into the medium during digestion are located in the cell wall outside the plasma membrane, whereas the Mg(2+)-dependent adenosine triphosphatase is an enzyme of the plasma membrane. This enzyme differs from the phosphatases with pH optima in the range pH3-4 with regard to location, pH optimum, substrate specificity and different requirement of activators.     

Chicken atrial natriuretic peptide (chANP) and its secretion

Summary An immunohistochemical study using antiserum raised against synthetic chicken natriuretic polypeptide was used to investigate the distribution of this peptide in the chicken heart. Immunoreactive cells, both in the atrial and ventricular walls, were identified by electron microscopy, and electron-dense granules in the atrial and ventricular cardiocytes were revealed to be storage sites of the peptide. The electron-dense material, thought to be the peptide, was found in the sarcoplasmic reticulum, and it is suggested that a secretory pathway of the peptide through the latter to extracellular space, may be present, in addition to an exocytotic one.     

Recent microscale disturbance of gene flow in threatened fluvial lamprey, Lethenteron sp. N, living in a paddy water system

We investigated whether the installation of sluice gates hindered gene flow among subpopulations of a fluvial lamprey, Lethenteron sp. N, inhabiting a paddy water system. Individuals were collected from three study sites and were genotyped at six polymorphic microsatellite loci. Our calculations indicated that, historically, gene flow among the subpopulations was frequent and bidirectional; however, contemporary gene flow was unidirectional (upstream to downstream). This indicates that the sluice gates have obstructed the movement of individuals between different subpopulations. Despite this, genetic diversity was similar across all three study sites. Thus, while the fluvial lamprey population does not appear to be in danger of losing genetic diversity, continued isolation is likely to affect gene flow by reducing migration between subpopulations. We recommend a management scheme wherein the sluice gates are periodically opened in order to facilitate migration. Since lampreys are an important part of the ecosystem, this should also help maintain the health of the paddy environment in general.     

Immunohistochemical study of atrial natriuretic polypeptides in the embryonic,fetal and neonatal rat heart

Summary An immunohistochemical study of atrial natriuretic polypeptides was carried out on embryonic, fetal and neonatal rat hearts, using an antiserum raised against -human atrial natriuretic polypeptide (-hANP). Weakly immunoreactive cells were seen in both atrial and ventricular walls at 11 days post coitum (pc). After this stage, the immunoreactive cells became more intensely stained in both atrial and ventricular walls. The immunoreactivity during the prenatal period was stronger in the superficial cell layer beneath the endocardium, than in the deep cell layer of the atrial wall. The cells in the trabecular meshwork also had an apparent, but weak, immunoreactivity, which showed a greater intensity in the left ventricle than in the right one. It is suggested that these immunoreactive cells in the ventricle may differentiate, in situ, into the cells of the impulse-conducting system during the further development of the heart.This research was supported in part by Grants-in-Aid for Scientific research to C. ura from the Ministry of Education of Japan (Nos. 5957009, 59570010)     

Polymorphic DNA haplotypes at the phenylalanine hydroxylase (PAH) locus in Asian families with phenylketonuria (PKU)

DNA polymorphisms at the phenylalanine hydroxylase (PAH) locus have proved highly effective in linkage diagnosis of phenylketonuria (PKU) in Caucasian families. More than 10 RFLP sites have been reported within the PAH structural locus in Caucasians. With information from affected and unaffected offspring in PKU families it is often possible to reconstruct complete RFLP haplotypes in parents and to use these haplotypes to follow the segregation of PKU within families and to determine the distribution of PKU chromosomes within populations. To establish the utility of these RFLPs in characterizing Asian families with PKU, we typed eight DNA sites in 21 Chinese families and 12 Japanese families with classical PKU. The eight RFLPs were chosen for their informativeness in Caucasians. From these families we reconstructed a total of 91 complete PAH haplotypes, 44 from non-PKU chromosomes and 47 from PKU-bearing chromosomes. Although all eight marker sites are polymorphic in both Chinese and Japanese, there is much less haplotypic variation in Asians than in Caucasians. In particular, one haplotype alone, haplotype 4, accounts for more than 77% of non-PKU chromosomes and for more than 80% of PKU-bearing chromosomes. Haplotype 4 is also relatively common in Caucasians. The next most common Asian haplotype is 10 times less frequent than haplotype 4. By contrast, in many Caucasian populations the sum of the frequencies of the five most common haplotypes is still less than 80%, and several of the most common haplotypes are equally frequent. Even though the extent of haplotypic variation in Asians is severely limited, the few haplotypes that are found often differ at a number of RFLP sites.(ABSTRACT TRUNCATED AT 250 WORDS)     

Application of a reverse line blot assay to the study of haemoparasites in cattle in Uganda

Recent advances in genomic technology have focused many veterinary researchers on the possibility of producing one multivalent recombinant vaccine against all the haemoparasites that infect cattle in the tropics. Before such a vaccine is developed it is essential to define target cattle populations as well as the range of anti-pathogen vaccines required in order to control disease. To further this objective, we have evaluated a reverse line blot (RLB) assay, which simultaneously detects the principal tick transmitted protozoan and rickettsial cattle pathogens, in different epidemiological scenarios in Uganda. A critical question is the sensitivity, particularly in relation to detecting carrier animals. As Theileria parva is considered to be the most important pathogen in the region, we assessed the sensitivity of the RLB assay for T. parva and showed that 1-2 x 10(3) parasites per ml of blood could be detected-a level comparable with previously developed PCR methods and well below conventional microscopic detection. We applied the RLB assay to evaluate the differences in pathogen profiles between crossbred and indigenous cattle and show that there were different profiles, with a low prevalence of T. parva and Theileria taurotragi in the indigenous cattle compared to a high prevalence in the crossbred cattle. In contrast, we show higher prevalences of Theileria mutans and Theileria velifera in the indigenous compared to the crossbred cattle. Interestingly Anaplasma marginale, Babesia bovis and Babesia bigemina were of low prevalence but a high prevalence of Ehrlichia bovis was seen, raising the question of whether this rickettsial species could be pathogenic in cattle. Analysis of animals with clinical symptoms of East Coast Fever showed that, while T. parva is a major cause of these symptoms, T. mutans and possibly T. taurotragi and T. velifera, may also cause clinical disease. Overall, the results presented here highlight the complexity of tick-borne pathogen infections in cattle in Uganda.     

Input-output budget of nitrogen and the effect of experimentally changed deposition in the forest ecosystems in central Japan

To evaluate the current nitrogen (N) status in Japanese forests, field measurements of rainfall, throughfall, litter layer percolation, and soil solution percolation were conducted in a red pine stand (Kannondai) and a deciduous stand (Yasato) located in central Japan. N input via throughfall was 31 and 14 kg ha(-1) year(-1) and output below rooting zone was 9.6 and 5.5 kg ha1 year(-1) in Kannondai and in Yasato, respectively. Two thirds of input N were retained in plant-soil systems. Manipulation of N input was carried out. Ionic constituents were removed from throughfall with ion exchange resin at removal sites and ammonium nitrate containing twice the N of the throughfall was applied at N addition sites periodically. SO4(2-) output below 20-cm soil layer changed depending on the input, while NO3- output was regulated mainly by the internal cycle and effect of manipulation was undetected. These Japanese stands were generally considered to have a larger capacity to assimilate N than NITREX sites in Europe. However, N output fluxes had large spatial variability and some sites in Kannondai showed high N leaching below rooting zone almost balanced with the input via throughfall.     

Studies on the biochemical action of ginseng saponin. I. Purification from ginseng extract of the active component stimulating serum protein biosynthesis.

Systematic isolation and purification of the biologically active component of ginseng extract were followed by observing the incorporation of labeled leucine into serum protein at 6 hr after a single intraperitoneal injection in a mouse. Ginseng saponin mixture (fraction 5) exhibited high activity for such incorporation. Seven saponins were isolated from fraction 5 by means of preparative TLC, and assayed. Administration of all these saponins (ginsenoside-Rb2, Rc, Rc2, Rd, Re, and Rg1)except for ginsenoside-Rb1, caused an increase of leucine incorporation over that in control animals. The incorporation rate was directly proportional to the dose in the case of ginsenoside-Rd, which had the highest activity. The increase specific radio-activity of serum protein was not due to a decrease in the pool size of free amino acids in the liver. It was conclusively shown that the active component stimulating serum protein biosynthesis is saponin.