Digestibility of phosphorus in protein-rich ingredients for pig diets

Two experiments were run to determine the digestibility of phosphorus in different vegetable and animal proteins for the pig diet. Each experiment comprised two 4 x 4 Latin squares run concurrently. Pigs initially weighing 30 kg were kept in metabolism crates and fed twice daily at about 2.5-fold metabolisable energy requirement for maintenance. A semi-purified basal diet low in phosphorus and without intrinsic phytase activity was fed either alone or after blending into mixtures with one of the ingredients to be tested. Mixtures were calculated to contain not more than 2 g digestible P/kg DM and between 5.0 and 6.0 g Ca/kg DM. Faeces and urine were quantitatively collected for 8 days after 7 days of adaptation. Phosphorus digestibility for ingredients under test was calculated assuming the digestibility of phosphorus from the basal diets to be constant in all diets. P digestibilities in solvent extracted soybean meal from dehulled seed, rapeseed and solvent extracted rapeseed meal were 37, 42 and 24%, respectively. Supplementation of a microbial phytase (750 U/kg diet) improved digestibility coefficients significantly to 76, 66 and 73%, respectively. Digestibility of phosphorus in 3 different batches of fish meal ranged from 85 to 90%, without significant differences between batches. In 3 different types of carcass meal, digestibility coefficients were 80, 82 and 83% without significant differences between types, and digestibility of phosphorus from bone meal was 80%.

Regulations for combined effects of pollutants: consequences from risk assessment in aquatic toxicology

In the analysis of combined effects two reference concepts are currently considered as equally valid for the assessment of mixture toxicities: these are LOEWE additivity (concentration addition) and BLISS independence (response addition) (Greco et al., 1995). The aim of this study of 137 binary mixtures of pesticides and surfactants using an algal biotest was to find rational procedures for the assessment of mixture toxicities in the aquatic environment. By introducing an index on prediction quality the quantitative relationships between predicted and observed effects are evaluated for each concept. It is shown that LOEWE additivity leads to good predictions of mixture toxicities for most combinations, whereas BLISS independence tends to underestimate mixture toxicities. By this it is reaffirmed that there is a solid basis for forthcoming regulatory activities on mixtures of chemicals.

Converging evidence for domain-specific slowing from multiple nonlexical tasks and multiple analytic methods

Older and young adults were tested on eight nonlexical tasks that overlapped extensively in complexity: disjunctive choice reaction time, line-length discrimination, letter classification, shape classification, mental rotation, visual search, abstract matching, and mental paper-folding. Performance on the first seven tasks was associated with equivalently low error rates in both groups, making it possible to directly compare their response times (RTs) on these tasks. Consistent with domain-specific slowing, the relationship between the RTs of the older adults and the RTs of the young adults was well described by a task-independent mathematical (Brinley) function. Evidence from this analysis and from analyses based on task-specific information-processing models leads to similar conclusions and provides converging support for general cognitive slowing in the nonlexical domain.

A property level analysis of lexical semantic representation in Alzheimer's disease

In order to assess the hypotheses that Alzheimer's disease (AD) results in a property level restructuring, loss, or degradation of lexical-semantic knowledge, Alzheimer's patients and normal elderly subjects were presented with a property verification task in which they were asked to judge the truth value of telegraphic statements which paired objects with their properties (e.g., "Apple is red."). Objects with either high- or low-typical exemplars of categories (e.g., "oak" is a high typical exemplar of the category "tree." while "palm" is a less typical item). Properties were varied with respect to normatively determined dominance (e.g, "fins" is a high dominant property of "trout," while "slimy" is a less dominant property) and whether they were distinctive (i.e., served to distinguish between subsets of exemplars within a category) or shared among most or all category members (e.g., "stem" for the category "fruit"). Analyses of accuracy and reaction time data suggested that AD results in neither a loss per se of representation of properties, nor a reorganization of relations between objects' properties. However, results were consistent with a property level degradation of AD patients' object concepts. While there was no evidence for a differential degradation of distinctive vs shared properties, results suggested that AD patients have degraded representations of lower dominant properties and properties of low-typical category exemplars.

Linguistic processes in the two cerebral hemispheres: implications for modularity vs interactionism

Three experiments are reported on lexical decision to target stimuli presented to the right or left visual field (RVF, LVF) following a variety of priming stimuli, words, incomplete sentences, and scrambled sentences. Lexical decision performance is always superior for stimuli presented to the RVF. Primes always facilitate the discrimination of words from nonword target stimuli presented to either visual field. However, when the prime is a sentence which is completed syntactically and semantically by a target word (normal, congruent sentence), the facilitation for RVF presented targets is significantly greater than for LVF targets. When the prime is either: (1) a single word, (2) a nonstructured (scrambled) sentence, or (3) a noncongruent-related sentence, the difference in facilitation between RVF and LVF presented targets is much smaller. These data are discussed with respect to (1) the nature of priming by sentences versus words, (2) language processing by the two hemispheres, and (3) modularity versus interactionism in language processing.

Genome analysis of the moss Physcomitrella patens (Hedw.) B.S.G

A wild-type (WT) strain of the moss Physcomitrella patens (Hedw.) B.S.G., two mutants derived from it (PC22 and P24), and a somatic hybrid, PC22(+)P24, were analysed. Staining of metaphases revealed 54 +/- 2 chromosomes in the somatic hybrid and 27 chromosomes in the wild type and the two mutants. Using flow cytometry (FCM), DNA contents were calculated to be 0.6 pg (WT, PC22), 1.2 pg (P24), and 1.6 pg (PC22(+)P24) per nucleus, respectively. Southern hybridization provided evidence for at least one family of highly repetitive DNA and, furthermore, revealed different amounts of repetitive DNA in the four genotypes. However, these sequences cannot account for the 100% increase in the nuclear DNA amount in mutant P24, relative to wild type. In FCM analyses every moss genotype generated just one single peak of fluorescence, indicating an arrest in the cell cycle during the daytime. Thermal denaturation of wild-type DNA revealed a G+C content of 34.6% for total DNA and 38.6% for plastid DNA. A cDNA library of 1.2 x 10(6) independent clones was established, from which sequences homologous to cab and rbcS, respectively, were isolated. These genes show significant homologies to those of higher plants, and, likewise, comprise multigene families. No restriction fragment length polymorphisms could be detected between the four moss genotypes using these cDNA probes.

Hemispheric specialization or reading habits: evidence from lexical decision research with Hebrew words and sentences

This paper reports the results of a lexical decision-visual hemifield protocol using Hebrew words and nonwords. The lexical decision task was combined with sentence priming to examine the impact of hemispheric specialization and sentence length. The data are relevant to the Kirsner and Schwartz (1986) hypothesis that reading habits can explain the oft-reported right visual field (RVF) superiority in linguistic tasks. Both the target stimuli and the sentence primes were in Hebrew and 26 male right-handed native Hebrew speakers served as subjects. Hebrew is written and read from right to left. Therefore, according to the favorable foveal viewing explanation (Kirsner & Schwartz, 1986), there should have been no RVF superiority. The results indicated, however, highly significant RVF superiority. Furthermore, priming sentences, written in Hebrew, should direct the attention of the subject to the left visual field in expectation of the appearance of a target word. Nevertheless, the RVF superiority was even more significant when target stimuli were preceded by priming sentences. Both results indicated that reading habits and directed reading attention cannot explain RVF superiority in lexical decision.

[Sleep-related respiratory disorders: early detection and follow-up by close patient contact]

Sleep apnoea (SA) ist a challenge to clinical research, since it occurs in up to 10% of the male professionally active population. It is indeed a challenge in respect of diagnosis, clinical aspects and therapy. SA is not only responsible for mental handicaps during daytime caused by disturbed sleep (increased tendency to doze or fall asleep, proneness to accidents), it will also enhance morbidity and mortality in aspect of cardiopulmonary and cardiovascular diseases (hypertension, cardiac insufficiency, disturbances of cardiac rhythm). All kinds of secondary and/or subsequent damage are reversible, provided diagnosis and rigidly introduced and maintained treatment have been performed well in time. SA can be diagnosed, treated and followed up by means of methods that can be flexibly employed outside the hospital, i.e. on an outpatient basis, such as questionnaires, MESAM IV, behavioural counselling, drug therapy). Within the framework of the current three-year project a stepwise concept was developed for diagnosis and treatment that also includes outpatient examination procedures. This system integrates anamnesis, outpatient monitoring, sleep laboratory, therapy and therapy control into a comprehensive feedback system of patient care. The following standardised procedural steps are included in the outpatient part of this system: baseline examination, treatment that can be performed on an outpatient basis, short-term, medium-term and long-term therapy follow-up. If these steps do not yield satisfactory results or if there is a high acute risk, the patient is subjected to in-patient treatment. At present, 683 first examinations and 420 follow-ups have been recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

The genomic structure of the human UFO receptor

Using a DNA transfection-tumorigenicity assay we have recently identified the UFO oncogene. It encodes a tyrosine kinase receptor characterized by the juxtaposition of two immunoglobulin-like and two fibronectin type III repeats in its extracellular domain. Here we describe the genomic organization of the human UFO locus. The UFO receptor is encoded by 20 exons that are distributed over a region of 44 kb. Different isoforms of UFO mRNA are generated by alternative splicing of exon 10 and differential usage of two imperfect polyadenylation sites resulting in the presence or absence of 1.5-kb 3' untranslated sequences. Primer extension and S1 nuclease analyses revealed multiple transcriptional initiation sites including a major site 169 bp upstream of the translation start site. The promoter region is GC rich, lacks TATA and CAAT boxes, but contains potential recognition sites for a variety of trans-acting factors, including Sp1, AP-2 and the cyclic AMP response element-binding protein. Proto-UFO and its oncogenic counterpart exhibit identical cDNA and promoter regions sequences. Possible modes of UFO activation are discussed.

Hemisphericity and top-down processing of language

This study investigated the impact of contextual prompts (priming words and sentences) on the classical finding of superior performance with right visual field stimulation in a lexical decision task. Subjects were presented with prompts of varying lengths (one, three, or six words). The prompts were followed by a target stimulus (word/nonword) to the right or the left visual field. Subjects were required to respond whether the target was a word or a nonword. The major purpose of the study was to determine the extent of right visual field (RVF) superiority, reflecting left hemisphere superiority, in language processing when target stimuli are preceded by semantically meaningful prompts. The results showed that increasing the number of priming words congruent with the target (creating a meaningful context) increased the advantage of the RVF over the left visual field presentation in lexical decision. Thus, even with an available strategy provided by congruent priming stimuli, RVF superiority in lexical decision is retained and even increased.

The murine ufo receptor: molecular cloning, chromosomal localization and in situ expression analysis

We have cloned the mouse homologue of the ufo oncogene. It encodes a novel tyrosine kinase receptor characterized by a unique extracellular domain containing two immunoglobulin-like and two fibronectin type III repeats. Comparison of the predicted ufo amino acid sequences of mouse and man revealed an overall identity of 87.6%. The ufo locus maps to mouse chromosome 7A3-B1 and thereby extends the known conserved linkage group between mouse chromosome 7 and human chromosome 19. RNA in situ hybridization analysis established the onset of specific ufo expression in the late embryogenesis at day 12.5 post coitum (p.c.) and localized ufo transcription to distinct substructures of a broad spectrum of developing tissues (e.g. subepidermal cells of the skin, mesenchymal cells of the periosteum). In adult animals ufo is expressed in cells forming organ capsules as well as in connective tissue structures. ufo may function as a signal transducer between specific cell types of mesodermal origin.

[Sleep-related respiratory disorders: from syndromes to risk factors]

In the past, sleep related breathing disorders (SRBD) have been described rather heterogeneously in terms of complex diseases, syndromes. During the past ten years, the relevant pathogenetic mechanisms of most of the SRBD could be defined, and data concerning their epidemiology were collected. Epidemiology and dangerousness being relevant criteria, the obstructive sleep apnea syndrome must be regarded as the most considerable SRBD. According to ICSD, the prevalence of a manifest obstructive sleep apnea syndrome is estimated at 1% of the entire population at least. Our measurings have shown that more than 10% of the middle-aged (20 to 60 years) male population suffer from 10 and more mixed obstructive apneas per hour of sleep. In this group, also the other pathogenetic factors for the obstructive sleep apnea syndrome, namely hyperventilation and fragmentation of sleep due to central arousal reactions, are found. All these patients snore, and there is a broad transition from primary snoring, which has no effects on the cardiovascular system and the blood gases, via obstructive snoring up to inter-apneic snoring. With the help of today's technical equipment, it is possible to determine the role of subclinical SRBDs in terms of risk factors, e.g. for cardiovascular diseases. We expect a plain contribution to the clearing up of instances of arterial hypertonus, early invalidity, and mortality.

Evaluation of the isobologram method for the assessment of mixtures of chemicals. Combination effect studies with pesticides in algal biotests

The aim of this paper is an evaluation of isobolograms, a method proposed for the assessment of combined effects of chemicals. In order to examine potentials and shortcomings of this approach for ecotoxicological purposes, algal biotests with selected pesticidal compounds were performed. Additivity, as defined by the model, is demonstrated for the combination of atrazine and metribuzin for different combination ratios, response levels, and parameters. Subadditivity is shown for amitrole and glufosinate-ammonium. The results and inherent biometrical features are discussed in terms of criteria considered suitable for comparative evaluation of biometrical models for the assessment of mixtures of chemicals.

Occupational performance of a paced secondary task under conditions of sensory deprivation. I. Heart rate changes in train drivers as a result of monotony

Twelve experienced train drivers were asked to operate the train function safety circuit (SIFA)--a paced secondary motor task which is expected to guarantee the driver's fitness for service on engines of the German Federal Railway--under laboratory conditions of extreme monotony. In spite of massive decreases in vigilance as shown by theta-activity in the EEG, all subjects were able to operate the device without major errors. A prerequisite for adequate performance is an EEG-defined arousal reaction, which is synchronized with the SIFA cycles. For 7 subjects the time-related cross-correlation coefficients between SIFA operation, alpha-activity (indicative of alertness), theta-activity (indicative of reduced vigilance), and heart rate were calculated. The central-nervous arousal found in the EEG corresponded to distinct increases in heart rate. The moments of SIFA operation after phases of light sleep correlated significantly and positively with increases in heart rate. These increases constituted a physiological overcompensation as far as the physical readiness was concerned which reached its peak after the task had been performed satisfactorily, constituting additional and superfluous occupational stress. The results of this study indicate clearly that monotony stress is not a result of occupational monotony itself, but the result of the physiological effort which is required in order to regain a level of alterness which allows adequate performance under monotonous conditions.

Occupational performance of a paced secondary task under conditions of sensory deprivation. II. The influence of professional training

Twelve truck drivers operated the train function safety circuit (SIFA), a paced secondary task used as a job monitor on German railways engines, under laboratory conditions of extreme monotony, in a comparison with 12 train drivers who were well acquainted with SIFA. Alertness was determined by means of EEG evaluations. Heart rate was monitored as the parameter for physical load, and the precoded SIFA tasks as the active response parameter. In spite of significantly more frequent and more distinct decreases in alterness, the SIFA-trained subjects (TS) performed better. Nine out of 12 TS reached the stage of light sleep at least once during the experimental run, as compared to 4 out of 12 untrained subjects (US). Nevertheless, the ratio acoustic warnings/occurrence of light sleep was significantly lower in TS (P less than 0.01), and there were three operational errors (equivalent to emergency braking) in US. Whereas US received fewer acoustic warnings in the stages of slightly reduced altertness, this trend was reversed as soon as low frequency theta-activity appeared in the EEG. A time-related calculation of the cross-correlation coefficients between SIFA operation, alpha-activity, theta-EEG-activity, and heart rate showed that timing of SIFA operation interrupting phases of light sleep correlated significantly and positively with increases in heart rate. The results suggest that a mechanism of rhythmic central nervous arousal interrupting phases of decreased alertness/drowsiness can be learned, whereas the physiological consequences of the effort to prevent the deterioration of performance under conditions of monotony are not reduced by professional adaptation.

[Diagnosis of sleep apnea: required equipment for staged diagnosis]

In view of the high prevalence of sleep apnoea (SA) a stepped concept for diagnosis and therapy is needed. Such a concept requires appropriate instrumentation. The apparative requirement for a five-stage concept, and the experience gained with it, are presented, in particular these newly introduced stages: screening instrument, based on an analysis of heart rate and breathing sounds, and a mobile sleep laboratory based on oxygen saturation measurement combined with inductive plethysmography and four further parameters. Experience obtained with such a stepped concept demonstrates its efficiency and necessity in the diagnosis of sleep-related breathing disturbances.

[Diagnosis of sleep apnea: initial experiences with a staged procedure]

The high prevalence of sleep-related breathing disturbances (SRBD), in association with cardiopulmonary disease, and the impairment by such disorders of the quality of the patients life, together with the good response of SRBD to therapy when diagnosed early on, point up the importance of incorporating the diagnostic evaluation of SRBD into the routine medical and pneumological diagnostic work-up. Since classical polysomnography requires a considerable effort, a stepwise diagnostic procedure was needed for use in practice. This includes a narrowing down of the indications, a brief questionnaire and a detailed questionnaire. For positive demonstration of a respiratory disturbance or differential diagnostic purposes, the following measures are employed on an outpatient basis in the following order: High-resolution 24-hour (Holter) ECG; analysis of heart rate and respiratory sounds, including, in particular snoring, with the MESAM system; induction plethysmography and continuous oxygen partial pressure measurement (pO2tc). Only after exhaustive use has been made of the ambulatory work-up, are the following diagnostic inhospital measures employed in the order indicated: 10-channel recording using the SIDAS system (respiration 3 channels, oxygen saturation, EOG, actogram, heart rate, intrathoracic pressure fluctuations), complete polysomnography. Once SRBD has been established, the patient is sent to the sleep laboratory to establish a baseline. Baseline measurement is accompanied by the determination of a marker, that is, a readily determined parameter capable of providing information about the success of therapy, is established. This permits complete polysomnography to be concentrated on differential-diagnostic and treatment-refractory problem cases.(ABSTRACT TRUNCATED AT 250 WORDS)

[Long-term acceptance of nasal continuous positive airway pressure therapy in 70 patients with sleep apnea over a 6-month treatment period]

NCPAP therapy is considered to be an effective method of treatment in cases of obstructive and mixed sleep apnea (SA). We investigated its effectiveness during initiation of therapy, and the acceptance of the ambulatory long-term treatment. Here we present the first 70 patients (68 m, 2f) treated with nCPAP for at least six to a maximum of 20 months (on average: eleven months). Sixty-seven of the 70 patients were effectively treated with a nCPAP pressure of 5-15 mbar. The apnea index was reduced from 49 apnea episodes per hour (range 12-125) to 2 episodes per hour (range 0-8) on average. Therapy failed in one case (anatomical defect of the nasopharynx) and had to be abandoned in two cases (claustrophobia, acute rhinitis). Sixty-three patients, decided in favour of ambulatory long-term therapy. These patients were asked to complete a questionnaire about their experience with nCPAP. Four patients abandoned therapy (all within the first four weeks because of intolerance towards the apparatus), and one patient died 10 days after terminating treatment of an infection of the upper airway. Fifty-eight patients (82% of all) are still undergoing treatment. Eighty-eight per cent of these are using nCPAP for 5-7 nights a week throughout the entire sleep period, or at least for five hours. All patients report a marked reduction in or elimination of subjective symptoms. Mild local side effects occur quite frequently, but can be greatly reduced or eliminated in most cases. In individual cases they lead to a shortening of the nocturnal duration of application.(ABSTRACT TRUNCATED AT 250 WORDS)

[Snoring and sleep apnea syndrome]

Sleep apnea and obstructive snoring are sleep related breathing disorders (SRBD). Nevertheless, there is only a quantitative difference between snoring and the obstructive form of sleep apnea. Snoring occurs in at least 20% of the population; 50% of the 50 year old male snore. Although in most of the cases only harmless snoring is concerned. It becomes serious if it leads as the independent SRBD "obstructive snoring" to a continuous oxygen desaturation and a sleep disturbance or, if in cases of sleep apnea a postapnoic snoring is concerned. The snoring pattern "loud and irregular" is always a sign for a serious SRBD. Still, no exact statement can be given concerning the frequency of obstructive snoring. However, the prevalence of sleep apnea in men of the mean age group has been determined to 10%. By the so-called sleep apnea syndrome are summarized clinical pictures with symptoms and findings caused by sleep apnea, respectively with those which can be reduced by sufficiently early introduced therapy. Most frequent symptoms and findings are: hypertension, loud and irregular snoring, daytime sleepiness and nocturnal cardiac arrhythmias. Especially hypersomnia has always to be taken seriously. In relation with other symptoms and findings associated with apnea it is always an indication for the examination for sleep apnea and obstructive snoring.

Lexical decision and visual hemifield: an examination of the RT-accuracy relationship

Visual hemifield, stimulus duration and angle of eccentricity were manipulated using a lexical decision paradigm (discrimination of words from non-words). Lexical decision was measured by several dependent variables: reaction time, (RT); accuracy, d'; and beta. The results support the generalization of RVF superiority in a lexical decision task for parafoveal stimulation for three dependent variables, RT, accuracy and d'. No significant effect of any stimulus manipulation was found for beta. When RT is plotted as a function of accuracy, the data separate into two groups (one for words, one for non-words) each best described by a linear equation with negative slope. The implication of this analysis is discussed, and the hypothesis offered that the same basic process discriminates words from non-words in a lexical decision task, regardless of visual field, parafoveal angle of eccentricity or stimulus duration. Visual field is processed no differently from the other stimulus manipulations.

Effect of paclobutrazol on water stress-induced abscisic Acid in apple seedling leaves

Abscisic acid (ABA) was quantitated by enzyme-linked immunosorbent assay (ELISA) in water-stressed leaves from control apple seedlings, and also from apple seedlings treated for 28 days with paclobutrazol ([2RS, 3RS]-1-[4-chlorophenyl]-4,4-dimethyl-2-[1,2,4-triazol-1-yl] pentan-3-ol). The ELISA quantitative estimates were also validated by gas chromatography-electron capture detector and lettuce seed germination inhibition bioassay. Paclobutrazol treatment reduced endogenous ABA levels by about one-third, and prevented the marked accumulation of water-stress-induced ABA that occurred in untreated seedlings. The presence of ABA in the apple leaf extracts was confirmed by gas chromatography-mass spectrometry.

Translocation of paclobutrazol, a gibberellin biosynthesis inhibitor, in apple seedlings

The [(2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1- yl)-pentan-3-ol] (paclobutrazol, PP333) measured in apple seedlings (;York Imperial' Malus domestica Borkh) was confirmed by gas chromatography-mass spectrometry. Data showed that paclobutrazol was taken up through roots and transported primarily in the xylem through the stems and accumulated in leaves. No detectable basipetal movement of paclobutrazol in apple seedlings was found.

Storytelling as an age-dependent skill: oral recall of orally presented stories

During experiment 1, three taped prose passages read by college student, middle-aged, or old tellers were orally recalled by college students in an incidental memory paradigm. More story units were remembered as the age of the teller increased (r = +.642, p less than .05). Comparison of these results, with prior research using written, as opposed to oral, presentation and recall of these stories, showed no differences in specific story units remembered. Teller age predicted recall on the two "storied" passages. These passages elicited more favorable comments from listeners when read by older tellers. The third, descriptive passage was less favorably regarded by listeners hearing older tellers. During experiment 2, taped storied passages read by middle-aged tellers were falsely attributed to young, middle-aged, or old persons before the college students listened. Incidental recall did not show an age of teller effect in this case, but the listener's evaluation of the speaker exhibited age-dependent stereotypes. It was concluded that 1) physical qualities of older voices lead to more effective oral transmission; 2) that one expects to receive certain types of oral information from older persons; and 3) that a mismatch between physical vocal quality and age attribution effects evaluation of the speaker, not recall of the information.

Social class distribution of fathers of children enrolled in the Iowa Autism Program

The social class distribution of fathers with autistic children attending a locally well-known and state-supported modern autism program was examined and was compared to the social class distributions observed in a nonautistic, mentally retarded population, in children with other psychiatric disorders, and in the general population from which the present autistic sample was drawn. No significant differences were found among the groups. The findings supported the view that if studies are not biased by certain selection factors outside the autistic child's clinical picture and diagnosis, and if services become better known and readily available, then no differences in social class distribution between autistic and nonautistic groups occur. The results suggest that social class is not an important factor in the origin of autistic syndrome.

Methylated constituents of poly(A)- and poly(A)+ polyribosomal RNA of sea urchin embryos

We have examined the poly(A)- and poly(A)+ polyribosomal (Ps) RNAs of developing sea urchin embryos to see whether they contain the capped structures previously observed in the poly(A)+ cytoplasmic RNA (mRNA) of a variety of eucaryotic organisms. We have found that both classes of Ps RNA contain 7-methylguanosine linked to the RNA by a 5'-5' triphosphate bridge. Capped structures derived from either class of Ps RNA appear to be of the type m7G5'ppp5'NmpNp, with only a single sugar-methylated nucleoside per cap, and we have estimated that both classes of Ps RNA are capped to the same extent. The 5' terminal 2'-0-methylated nucleosides have been identified and quantitated. The relative amounts are Am = 78%, Gm = 14%, Cm = 5%, Um = 3% for poly(A)- Ps RNA, and Am = 78%, Gm = 15%, Cm = 5%, Um = 2% for poly (A)+ Ps RNA. In addition, both classes of Ps RNA contain 2-4 internal residues of N6-methyladenylic acid per molecule.

m7G5'ppp5'GmptcpUp at the 5' terminus of reovirus messenger RNA

In the presence of S-adenosyl methionine the 5' terminal guanosine residue of in vitro synthesized reovirus mRNA becomes methylated at the 2'-OH position. In addition, 7-methyl guanylic acid is condensed covalently at the 5' terminus resulting in the formation of a 5' to 5' triphosphate bridge. Analysis of the 5' terminal sequence of methylated reovirus mRNA revealed that it has the structure m7G5'ppp5'GmpCpUp.

In vitro methylation of nascent reovirus mRNA by a virion-associated methyl transferase

Chymotrypsin-derived cores, but not virions, catalyze the transfer of methyl groups from S-adenosyl methionine (SAM) to nascent mRNA synthesized in vitro by the core polymerase. The reaction requires Mg(++), and is dependent on the presence of all 4 ribonucleoside triphosphates (rNTPs). Methylation proceeds optimally at 51 degrees C. All ten species of mRNA become methylated during transcription and it is estimated that one methyl residue is incorporated per RNA chain. Experiments designed to determine the location of the methylated nucleotide clearly demonstrate that methylation occurs exclusively at the 5' ends of nascent mRNA.

Glucose metabolism of various tissues of pear buds

Various tissues in flower buds of Pyrus calleryana Decne. differ in their metabolic activity. Brown outer scales utilized more exogenously supplied glucose, particularly through the pentose phosphate pathway, than did the central axes and the green inner scales. They also contained more endogenous reducing sugars, and glucose leaked out more readily from the brown scales than from the other tissues. In contrast, respiration of the central axes was nine times as great as that of the brown scales, and two to four times as much glucose was metabolized through glycolysis. Membranes of the central axes were less permeable to glucose. Because the brown scales are 75% of the dry weight of the bud, they dominate its pattern of glucose metabolism.

Calcium transport in apple trees

(45)Ca, applied to roots of apple seedlings, moved readily to the developing leaves. Kinetin, benzyladenine, and B sprays increased movement. NO(3) (-) as the source of N increased movement and accumulation of Ca into mature leaves; NH(4) (+) increased movement into new leaves. Translocation in the stem is effected by a nonspecific ion exchange. Any divalent cation can free Ca for ascent. The exchange may be a property of lignin. Genetic differences in the uptake and translocation of Ca exist among apple seedlings. Those which show juvenile leaf characteristics translocate Ca into mature leaves more readily. Translocation of Ca in woody species appears to be similar to that reported for herbaceous plants.

Pear bud metabolism: seasonal changes in glucose utilization

Utilization of glucose, uracil and valine by flower and leaf buds of seedling pear trees (Pyrus calleryana Decne.) from the time of flower bud initiation to flowering was investigated. A very high rate of glucose utilization through the pentose phosphate pathway was observed throughout the development of buds. There was no difference in the type of glucose metabolism between flower and leaf buds except immediately before flowering, when the metabolism in flower buds was shifted toward the glycolytic pathway. Such a shift did not occur in leaf buds. The incorporation of uracil and valine into the nucleic acid and protein fraction of buds, respectively, was high throughout bud development, perhaps indicating a high rate of turnover in the resting buds. Incorporation of both compounds decreased when buds started to expand prior to flowering.

Ontogenetic changes in respiratory pathways in cortland apple skin during storage

Ontogenic changes in respiratory pathways of skins of detached apple fruits were measured during a 4 month period. Results showed that an increase in pentose pathway occurred with increasing senescence in this tissue. Variation in temperature at any given age did not result in an alteration of the C(6)/C(1) ratio. CO(2) evolution from the pentose pathway in senescent fruit was directly related to O(2) uptake. Glucose uptake increased with increasing senescence indicating a change in cell permeability.