Development of Induction Heating System Ensuring Increased Heating Efficiency of the Charge Material in a Forging

This study performs a complex analysis and review of the currently applied methods of inductively heating the charge material in hot die forging processes, as well as elaborates and verifies a more effective heating method. On this basis, a device for inductive heating using variable frequency inductors was designed and constructed, which made it possible to reduce the scale and decarburization with respect to the heater used so far. In the first place, the temperature distributions in the heater in the function of time were modeled with the use of the CEDRAT FLUX software. The aim of the research was to analyze the temperature gradient and value diversification on the surface and in the material core, as well as to determine the process stability. The following stage was designing and constructing a heater with an automatic system of loading and positioning of the charge on the exit, as well as with a possibility of working in a fully automated system adjusted to the work center. The last stage of investigations was the verification of the elaborated effective heating method on the basis of a short production series and a continuous work for the period of 8 h, both in the quantitative and qualitative aspect (reduced oxidation and decarburization as well as a gradient between the core and the surface). The obtained results confirm the effectiveness of the proposed solution referring to heating the charge material, especially in the aspect of stability and repeatability of the process, as well as a significant reduction in oxidation and decarburization of the material surface.

The prognostic value of fixed time and self-paced walking tests in patients diagnosed with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic fibrosing interstitial pneumonia that has an unknown etiology. The natural history of the disease is characterized by a progressive decline in pulmonary function and overall health and well-being. The median survival time is between 2-3 years; however, the disease course is variable and unpredictable. The twelve-minute walking test (12MWT) and six-minute walking test (6MWT) are two fixed time tests that are commonly used in clinical practice. Our short and clinically oriented narrative review attempted to summarize current evidence supporting the use of fixed time, self-paced walking tests in predicting the outcome of patients diagnosed with IPF. A number of studies have justified that the 6MWT is a simple, cost-effective, well documented, fixed time, and self-paced walking test which is a valid and reliable measure of disease status and can also be used as a prognostic tool in patients with IPF. However, there is a need for dedicated and validated reference equations for this population of patients. It is also necessary to fill the knowledge gap about the role of the 12MWT. We hypothesize that it would be useful in evaluating patients that are in the early stages of the disease.

MCORD - MPD Cosmic Ray Detector a new features

The main detector system at the Nuclotron-based Ion Collider fAcility (NICA) located in Dubna, Russia is the Multi-Purpose Detector (MPD). For better calibration reason, the MPD needs an additional trigger system for an off-beam calibration of MPD sub-detectors and for rejection (veto) of cosmic muons. The system should also be useful for practical astrophysics observations of cosmic showers. The consortium NICA-PL group defines goals and basic assumptions for the MPD Cosmic Ray Detector (MCORD). This article describes the conceptual design and simulation plans of the MCORD detector based on plastic scintillators with SiPM photodetectors and electronic digital system based on the MicroTCA crate.

State of The Art of Instrumentation in Experimental Nanodosimetry

Nanodosimetry is a branch of dosimetry for investigation and modeling of the interaction pattern of ionizing radiation in nanometre site-sizes (at unit density), which dates back to the 1970's (Pszona S. A track ion counter. Proceedings of Fifth Symposium on Microdosimetry EUR 5452 d-e-f, Published by the Commission of the European Communities, Luxemburg, pp. 1107-1122 (1976)). To date, the different experimental approaches have lead to developing of three fully functional nanodosimeters: the Jet Counter operated at NCBJ, the Ion Counter operated at PTB and Startrack Counter operated at INFN-LNL. Descriptions of each nanodosimeter as well as of the techniques used to investigate the track structure of ionizing particles are presented.

NANODOSIMETRY: TOWARDS A NEW CONCEPT OF RADIATION QUALITY

The biological action of ionizing charged particles is initiated at the DNA level, and the effectiveness with which the initial physical effect changes into measurable biological damage is likely ruled by the stochastics of ionizations produced by the incident ions in subcellular nanometric volumes. Based on this hypothesis, experimental nanodosimetry aims at establishing a new concept of radiation quality that builds on measurable characteristics of the particle track structure at the nanometer scale. Three different nanodosimetric detection systems have been developed to date that allow measurements of the number of ionizations produced by the passage of a primary particle in a nanometer-size gas volume (in unit density scale). Within the Italian project MITRA (MIcrodosimetry and TRAck structure), funded by the Italian Istituto Nazionale di Fisica Nucleare (INFN) and the EMRP Joint Research Project 'BioQuaRT' (Biologically Weighted Quantities in Radiotherapy), experiments have been carried out, in which the frequency distribution of ionizations produced by proton and carbon ion beams of given energy was measured with the three nanodosimetric detectors. Descriptors of the track structure can be derived from these distributions. In particular, the first moment M1, representing the mean number of ionizations produced in the target volume, and the cumulative probability Fk of measuring a number ν ≥ k of ionizations. The correlation between measured nanodosimetric quantities and experimental radiobiological data available in the literature is here presented and discussed.

The metabolic profile of growing lambs fed diets rich in unsaturated fatty acids

The effect of two diets enriched with unsaturated fatty acids--one containing the addition of dried distillers grains with solubles (DGS) and the other the addition of false flax--Camelina sativa cake (CS)--on some metabolic parameters and hormone concentration in growing lambs was determined in this experiment. A total of 21 ram lambs of the Polish Whiteheaded mutton sheep were divided into three groups (the control, receiving DGS and CS). The diets were administered to animals for 6 weeks. During the experiment, peripheral blood was collected. Glucose (GL), total cholesterol (CH), triglycerides (TG), free fatty acids (FFA), insulin (IN), leptin (LE), triiodothyronine (T3) and thyroxine (T4) were assayed in serum. The age-dependent reduction in CH and TG limited by both experimental diets were observed. A significant increase in FFA concentration was observed in samples collected in the last, that is, third, time period. This was most probably caused by a 12-h pre-slaughter fasting period. A significantly lower dynamic of FFA increase in that experimental period was found in animals receiving the experimental feed. Insulin concentration in DGS-receiving lambs was increased, in contrast to the CS-receiving lambs, in which it was lower when compared to the control. LE concentration was decreased by both experimental diets, more markedly in the DGS-receiving animals. No differences between the experimental groups and the control were observed in T3 and T4 concentrations. The effect of 12-h pre-slaughter fasting was statistically highly significant for the levels of examined blood markers and hormones, except for TG and IN in the group of lambs receiving the experimental diet with CS.

Quantum-chemical calculations of the electronic structure of 2-amino-1,3-dicyano-5,6,7,8-tetrahydronaphthalene derivatives

The UV-Visible absorption spectra of six, newly synthesized donor-substituted 2-amino-1,3-dicyano-5,6,7,8-tetrahydronaphthalene have been measured in methylcyclohexane (MCH) and assigned with the help of quantum-chemical calculations. Our calculations have been performed to assess information regarding the electronic state energy values, corresponding oscillator strengths, x-, y-, z-components of the transition dipole moments and molecular orbitals involved in the main electronic transitions of the studied compounds. Additionally, the experimental absorption transition dipole moments were calculated, on the basis of spectroscopic data, and compared with results of our quantum-chemical calculations. On the basis of the experimental results and quantum-chemical calculations, it was shown that the long-wavelength absorption band involves an overlap of three electronic transitions of different character. For all studied donor-acceptor (D-A) compounds in vapour-phase, the long-wavelength transition (S0→S1) does not possess charge transfer character, whereas the S0→S2 transition possesses electron transfer character e.g., π-electrons of the acceptor moiety are moved to the donor part. Moreover, it is found that the electronic structure of the studied biphenyl derivatives can be approximately described within composite-model of decoupled moieties: donor and acceptor.

Changes in the anaerobic threshold in an annual cycle of sport training of young soccer players

The aim of the study was to assess changes in the anaerobic threshold of young soccer players in an annual training cycle. A group of highly trained 15-18 year old players of KKS Lech Poznań were tested. The tests included an annual training macrocycle, and its individual stages resulted from the time structure of the sports training. In order to assess the level of exercise capacities of the players, a field exercise test of increasing intensity was carried out on a soccer pitch. The test made it possible to determine the 4 millimolar lactate threshold (T LA 4 mmol · l^-1) on the basis of the lactate concentration in blood [LA], to establish the threshold running speed and the threshold heart rate [HR]. The threshold running speed at the level of the 4 millimolar lactate threshold was established using the two-point form of the equation of a straight line. The obtained indicators of the threshold running speed allowed for precise establishment of effort intensity used in individual training in developing aerobic endurance. In order to test the significance of differences in mean values between four dates of tests, a non-parametric Friedman ANOVA test was used. The significance of differences between consecutive dates of tests was determined using a post-hoc Friedman ANOVA test. The tests showed significant differences in values of selected indicators determined at the anaerobic threshold in various stages of an annual training cycle of young soccer players. The most beneficial changes in terms of the threshold running speed were noted on the fourth date of tests, when the participants had the highest values of 4.01 m · s^-1 for older juniors, and 3.80 m · s^-1 for younger juniors. This may be indicative of effective application of an individualized programme of training loads and of good preparation of teams for competition in terms of players’ aerobic endurance.

Efficient design of multituned transmission line NMR probes: the electrical engineering approach

Transmission line-based multi-channel solid state NMR probes have many advantages regarding the cost of construction, number of RF-channels, and achievable RF-power levels. Nevertheless, these probes are only rarely employed in solid state-NMR-labs, mainly owing to the difficult experimental determination of the necessary RF-parameters. Here, the efficient design of multi-channel solid state MAS-NMR probes employing transmission line theory and modern techniques of electrical engineering is presented. As technical realization a five-channel ((1)H, (31)P, (13)C, (2)H and (15)N) probe for operation at 7 Tesla is described. This very cost efficient design goal is a multi port single coil transmission line probe based on the design developed by Schaefer and McKay. The electrical performance of the probe is determined by measuring of Scattering matrix parameters (S-parameters) in particular input/output ports. These parameters are compared to the calculated parameters of the design employing the S-matrix formalism. It is shown that the S-matrix formalism provides an excellent tool for examination of transmission line probes and thus the tool for a rational design of these probes. On the other hand, the resulting design provides excellent electrical performance. From a point of view of Nuclear Magnetic Resonance (NMR), calibration spectra of particular ports (channels) are of great importance. The estimation of the π/2 pulses length for all five NMR channels is presented.

Kinetics of C. elegans DcpS cap hydrolysis studied by fluorescence spectroscopy

DcpS (scavenger decapping enzyme) from nematode C. elegans readily hydrolyzes both monomethyl- and trimethylguanosine cap analogues. The reaction was followed fluorimetrically. The marked increase of fluorescence intensity after the cleavage of pyrophosphate bond in dinucleotides was used to determine K(m) and V(max)values. Kinetic parameters were similar for both classes of substrates and only slightly dependent on pH. The hydrolysis was strongly inhibited by methylene cap analogues (m(7)Gp(CH(2))ppG and m(7)Gpp(CH(2))pG) and less potently by ARCA (m(7,3' O)GpppG).

Neurodevelopmental rehabilitation according to Glenn Doman (the Philadelphia Neurodevelopment Method)

Neurodevelopmental rehabilitation methods for children with nonprogressive brain injury began to take shape in the late 1940s in the US and Europe. One of the most important centers continuously involved in promoting neurodevelopmental concepts is the Institute for the Achievement of Human Potential. The method of child neurodevelopment is based on the theory of neurological organization. In practice this global method seeks to provide the child's brain with ordered information suitable for his or her present level of development, with increasing duration, frequency, and intensity. As is the case with other rehabilitation methods, the theoretical foundations and clinical efficacy of these rehabilitation techniques have not yet been adequately documented, which has been pointed out by the numerous critics of these methods.

[Diagnostic value of sleep deprivation as the EEG activation method in diagnosis of epilepsy in developmental age]

The paper presented the significance of EEG activation in diagnosing epilepsy in children and adolescents. EEG records of 108 patients between 3-19 years of age with the occurrence of various types of paroxysmal disorders who were admitted to Chair and Department of Developmental Neurology University of Medical Sciences in Poznań were analysed. Standard EEG was administered to all children twice: the first examination at rest with hyperventilation (HV) and photostimulation (FS) and the second one after total or partial sleep deprivation (DS). At awaking state normal records were stated in 57% of cases, in 15% paroxysmal changes in HV or FS appeared, in the rest of cases (28%) generalised paroxysmal disorders, localised changes, lateralised or diffused were noted. Among EEG activation methods DS occurred to be the most effective after it, 52 patients (48%) were diagnosed for generalised paroxysmal changes, 20% for localised, 3% lateralised and for 6% for diffused changes. Normal EEG were recorded in 22% of examined children and adolescents. The epilepsy were diagnosed in 59 (55%) of patients mostly with generalised seizures (28) partial secondarily generalised (16) and partially complex (11). In 49 (45%) children were diagnosed with other paroxysmal disorders.

[Correlation between oncologically suspicious cytologic smears and colposcopic images of the uterine cervix and results of histopathologic examination taken from material provided by the Gynecology Department of the Pruszkow Municipal Hospital from 1995 to 1997]

The objective of the paper was an evaluation of relationship between oncologically suspicious cytologic smear and colposcopic images, and the results of histopathological examination of samples collected from the vaginal portion of uterine cervix and from cervical canal scrapings. The material consisted of 60 patients with cytologic group 3 and 13 patients with group 4 and 5 according to Papanicolaou, who had been selected during a two-year preventive examination period. Cytologic group 3 patients (group 1) were subjected to cytological assessment and colposcopic examination again in order to determine further diagnostic indications. Cytologic group 4 and 5 women (group 2) were collected samples from the vaginal portion of uterine cervix under colposcopic supervision, without waiting for the result of cytologic re-assessment. All these patients were also collected samples from the vaginal portion of uterine cervix. In patients of cytologic group 3 the cytologic and colposcopic examination results were found to be compatible with histopathologic examination results in 53.3% cases. In patients of cytologic group 4 or 5 this factor was established at 92.3%.

Culture of human nasal epithelial cells from nasal polyps on collagen matrix

Epithelial cell cultures became an experimental model employed for both animal and human studies. We established a modified method of culture of human nasal epithelial cells from nasal polyps using serum-free, hormonally supplemented Ham's F-12 medium and Vitrogen 100 collagen matrix. Cells reached confluent monolayer structures in 5 to 7 days (mean time 6 +/- 0.89 days) of culture. The confluent cultures consisted of pure epithelial cells, which was confirmed by light and electron microscopy, and immunohistochemical staining with anticytokeratin antibody. The success ratio of cultures was 61.5%. The culture system described is efficient enough to provide pure epithelial cells for further functional studies.

[A case of Potter syndrome in a male newborn infant]

The Potter syndrome was discussed based on the reference materials. The aim of the work is to present the course of pregnancy of 19-year-old nullipara ended by the delivery of male newborn with signs of above described syndrome.

Effect of rapid rigor mortis processes on protein functionality in pectoralis major muscle of domestic turkeys

The pale, soft, exudative (PSE) phenomenon in turkey pectoralis major (breast) muscle was studied using a combination of biochemical, meat quality, microscopic, and gel electrophoresis techniques. Breast muscle samples were collected from turkeys characterized by slow vs fast postmortem glycolysis assessed by muscle pH at 20 min after death. The PSE group was characterized by lower muscle ATP (P < .05) and higher lactate levels (P < .05) compared with the normal group. Excess water-holding capacity and cooking yield were significantly lower (P < .05) in the PSE group than in normal turkeys. Breast muscle of the PSE group was also lighter (P < .05) than that in the normal group as determined by Minolta L* values. The SDS-PAGE, Western blotting, and immunofluorescence microscopy revealed that phosphorylase, a soluble enzyme, became tightly associated with the myofibrils in muscle from the PSE group. Also, less myosin could be solubilized from PSE vs normal myofibril samples. The results indicate that irreversible myosin insolubility due to low pH and high-temperature conditions is decisive in the development of PSE turkey breast muscle.

Medical emergencies in commercial air travel

There are physiologic and logistic concerns involved in caring for patients with inflight emergencies. This article presents the physiologic changes that occur at altitude, the types of medical problems that can be encountered, and management strategies. An overview is also presented of the medical training of flight attendants and the medical equipment that is available on commercial aircraft.

Isolation and characterization of a cDNA from flowers of Cynara cardunculus encoding cyprosin (an aspartic proteinase) and its use to study the organ-specific expression of cyprosin

Poly(A)+ RNA isolated from flower buds of Cynara cardunculus has been used to prepare a cDNA library. Screening of the cDNA after expression of cloned DNA with antibodies raised against the large subunit of cyprosin 3 resulted in the isolation of six positive clones. One of these clones (cypro1s; a 1.7 kb Eco RI fragment) codes for cyprosin. The nucleotide sequence contain a 1419 bp open reading frame coding for 473 amino acids (aa) including a putative full-length mature protein (440 aa) and a partial prosequence (33 aa). Cypro1s contains a 162 bp 3' non-coding region followed by a poly(A) tail. The deduced amino acid sequence shows high homology to other plant aspartic proteinases. The homology to mammalian and microbial aspartic proteinases is somewhat lower. Plant aspartic proteinases contain an insert of around 100 aa. We are modelling where this plant-specific insert will appear in the structure of cyprosin. Using cypro1s as a probe in northern blot analysis, the expression of cyprosin in developing flowers and other tissues has been studied. The signal on the northern blot increased for RNA samples from early (flower buds 6 mm in length) to later stages of floral development (flower buds up to 40 mm in length). In late stages of floral development (open flowers 50 mm in length and styles from such flowers) no hybridization signal was visualized showing that the synthesis of mRNA encoding the cyprosin starts in early stages of floral development and switches off at maturation of the flower.(ABSTRACT TRUNCATED AT 250 WORDS)

Mutation analysis of the C-terminal vacuolar targeting peptide of tobacco chitinase: low specificity of the sorting system, and gradual transition between intracellular retention and secretion into the extracellular space

The C-terminal propeptide of tobacco (Nicotiana tabacum) chitinase A has been shown to be necessary and sufficient for targeting of chitinases to the plant vacuole. The sequence specificity of this vacuolar targeting peptide (VTP) has now been analysed using transient expression of chitinases in Nicotiana plumbaginifolia protoplasts. An extracellular cucumber chitinase, previously used as a secreted reporter protein in transgenic tobacco, was also secreted into the incubation medium by the transiently transformed protoplasts. Addition of six to seven amino acids at the C-terminus to generate the VTP of tobacco chitinase A were sufficient to cause retention of most of the cucumber chitinase within the protoplasts. The chitinase A itself, as well as a mutant lacking the N-terminal chitin-binding domain, were retained to 80% in the protoplasts when low concentrations of the plasmid were used in the transient expression system. At high concentrations of plasmid, causing high levels of transiently expressed chitinase, retention was reduced, indicating saturation of the sorting system. Deletion of the C-terminal methionine did not affect the intracellular location, but deletion of even a single internal amino acid of the VTP caused predominantly secretion of tobacco chitinase A. In contrast, exchanges of amino acids in the VTP as well as substitution of the VTP with random sequences had intermediary effects that covered the whole range from retention to secretion. The results suggest that the sorting system responsible for the diversion of secretory proteins to the vacuole has a low specificity for the sequence of C-terminal targeting peptides, and that sequence changes in the VTP allow a gradual transition from vacuolar retention to secretion.

Prehospital care and the military

Significant evolution has occurred in prehospital care over the past decade. Civilian emergency medical service (EMS) systems have become progressively sophisticated. Military systems have tended to maintain a wartime philosophy toward prehospital care, and thus its peacetime ambulance service, at times, is not prepared to provide the same standard of care given by the civilian community. This article reviews the current status of civilian and military EMS and attempts to put in perspective the directions that the military could go to improve on the prehospital care it provides.

Evaluation of minor head trauma in children younger than two years

The recent medical literature emphasizes the limitations of skull films in the evaluation of minor head trauma. However, the emergency medicine literature places little emphasis on the particular risks in children younger than 2 years old with blunt head injury. These children have immature bone and unfused sutures that may increase risk of cranial injury and delayed complications. A case is presented to illustrate this point. Unlike severe head trauma, where evaluation is directed toward computed tomography, the literature continues to be controversial regarding the indications for skull radiographs and computed tomography in minor head trauma. The authors recommend a low threshold for radiographic imaging in blunt heat injuries in children younger than 2 years.

Electrophoresis of DNA restriction fragments in poly-N-acryloyl-tris gels

Poly-N-acryloyl-tris(hydroxymethyl)aminomethane (NAT) gels were evaluated as a matrix for DNA electrophoresis. The resolution of DNA restriction fragments in three poly(NAT)-N,N'-methylenebisacrylamide (Bis) gels (4, 5, and 6%) was compared with the resolution in polyacrylamide (AA)-Bis gels of the same percentage. Poly(NAT) gels were found to give a substantially improved separation of DNA fragments larger than 200 bp. In contrast to poly(AA) gels, DNA fragments of up to 4 kbp were well resolved in the new matrix. By pulse-field electrophoresis the useful separation range of poly(NAT) gels was expanded to at least 23 kbp. For DNA fragments below 10 kbp, the resolution was better than that in a 0.7% agarose gel. Thus poly(NAT) gels are most suitable for the electrophoretic separation of DNA molecules whose size is out of the optimal fractionation range of poly(AA) or agarose gels.

Translation products of cauliflower mosaic virus ORF V, the coding region corresponding to the retrovirus pol gene

Open reading frame (ORF) V of cauliflower mosaic virus (CaMV), the candidate for the reverse transcriptase gene, has been expressed in E. coli under control of the PR promoter of bacteriophage lambda either as an N-terminal polypeptide fused to beta-galactosidase or as the total ORF V without fusion. Antibodies against these proteins were used to analyze extracts from CaMV-infected plants by immunoblotting. ORF V-specific polypeptides of 80, 62, 58, 22, and 18 kD apparent molecular weights were detected, with the largest species corresponding to the full length translation product. The 62 and 22 kD species could be assigned to the N-terminus and the remaining two species to the C-terminus of the ORF.

Expression in plants of two bacterial antibiotic resistance genes after protoplast transformation with a new plant expression vector

Two bacterial antibiotic resistance genes, one coding for the neomycin phosphotransferase (NPT I) from Tn903, and the other coding for the chloramphenicol acetyltransferase from Tn9 were used as plant selectable markers. Both genes were introduced into the Nicotiana tabacum genome in a new plant expression vector, using the direct gene transfer method. The vector pDH51, used in these experiments contains a plant expression unit as a movable cassette, consisting of the strong cauliflower mosaic virus (CaMV) 35S RNA promoter and transcription terminator separated by a polylinker containing several unique restriction sites.

Replication of the cauliflower mosaic virus: role and stability of the cloned delta 3 discontinuity sequence

A fragment of cauliflower mosaic virus (CaMV) DNA, containing delta 3, one of the three discontinuity sequences, was cloned in various ways into CaMV DNA deleted for the delta 3 sequence. The series of constructions was monitored for the appearance of the typical single-strand (ss) discontinuity after hybrid CaMV replication in plants. The delta 3 discontinuity was observed only if the orientation of inserted DNA sequence was the same as in the wild-type virus. Long polylinker sequences used for insertion of the fragment into cloned viral DNA, affected the stability of the insert in progeny viral DNA in plants by acting as recombination targets.

[Growth and maturation of children of normal short stature in the light of selected auxological determinants]

In longitudinal complex auxological studies of healthy short stature children in the first decade of life the authors analyse the dynamics of height velocity and growth rate of 11 somatic patterns with skeletal maturation of the hand and wrist as well as the influence of some genetic, paragenetic and biological determinants (morbidity). They find that the degree of stature deficit is on the same level during the period of observation (5-10 years) with slow growth rate in some of the analysed anthropological parameters. The delay of skeletal maturation typical for children under study is coexistent with a number of minor anomalies of hands and wrists which are more frequent than in healthy normal children. These minor anomalies are more frequent in boys than in girls. The analysed paragenetic determinants seem not to be significant, however there exists a strong association between the short stature of mothers and children under study. Moreover a higher morbidity of respiratory tracts is observed in short stature children than in general population.

Purification and properties of two ribonucleases and a nuclease from barley seeds

Three enzymes possessing RNAase activity were isolated from barley seeds. These enzymes were further purified by ammonium sulphate precipitation DEAE-cellulose chromatography, gel filtration on Sephadex G-75 and DEAE-Sephadex A-50 chromatography. These enzymes have been characterized and classified as: 1. Plant RNAase I (EC 3.1.27.1). It has a pH optimum at 5.7 and molecular weight of 19 000. 2. Plant RNAase II (EC 3.1.27.1). It has a pH optimum at 6.35 and molecular weight of 19 000. 3. Plant nuclease I (EC 3.1.30.2). It has a pH optimum at 6.8 and molecular weight of 37 000. Two RNAases were purified to homogeneity by means of affinity chromatography on poly(G)-Sepharose 4B, as shown by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.

Plant tRNA nucleotidyltransferase : I. Isolation and purification of tRNA nucleotidyltransferase from Lupinus luteus seeds

A method for purification of tRNA nucleotidyltransferase from Lupinus luteus L. seeds on a preparative scale is presented. This involved ammonium sulfate fractionation and chromatography on DEAE-cellulose, hydroxylapatite, and QAE-Sephadex A-50. The final enzyme prepartion was apparently homogeneous and a 2000-fold purification was achieved. Data presented suggest the existence of only one form of tRNA nucleotidyltransferase in dry lupin seeds.

Plant tRNA nucleotidyltransferase : II. Some properties of the purified enzyme from Lupinus luteus seeds

Purified lupine tRNA nucleotidyltransferase catalyzed only the incorporation of AMP and CMP into 3'-terminal-C-C-A sequences of tRNA as determined by terminal analysis of the reaction product. The incorporation of AMP and CMP was inhibited by their respective triphosphates to different degrees; UTP also showed an inhibitory effect. The pH optimum of the purified enzyme was found to be 9.5 in glycine buffer. The enzyme required magnesium or manganese ions for its activity.-SH reagents reversibly inhibited the action of the enzyme. Kinetic data, the different effects of ionic strength on the incorporation of AMP and CMP, and different rates of thermal inactivation for AMP and CMP incorporation in connection with chromatographic properties of the enzyme suggest the existence of only one form of tRNA nucleotidyltransferase with different catalytic sites for ATP and CTP.