Suppression of the maize phytoglobin ZmPgb1.1 promotes plant tolerance against Clavibacter nebraskensis.

MAIN CONCLUSION: Suppression of the maize phytoglobin ZmPgb1.1 enhances tolerance against Clavibacter nebraskensis by promoting hypersensitive response mechanisms mediated by ethylene and reactive oxygen species. Suppression of the maize phytoglobin, ZmPgb1.1, reduced lesion size and disease severity in leaves following inoculation with Clavibacter nebraskensis, the causal agent of Goss's bacterial wilt disease of corn. These effects were associated with an increase of the transcriptional levels of ethylene biosynthetic and responsive genes, which resulted in the accumulation of reactive oxygen species (ROS) and TUNEL-positive nuclei in the proximity of the inoculation site. An in vitro system, in which maize cells were treated with induced xylem sap, was employed to define the cause-effect relationship of these events. Phytoglobins (Pgbs) are hemoglobins able to scavenge nitric oxide (NO). Suppression of ZmPgb1.1 elevated the level of NO in cells exposed to the induced xylem sap causing a rise in the transcript levels of ethylene biosynthesis and response genes, as well as ethylene. Accumulation of ethylene in the same cells was sufficient to elevate the amount of reactive oxygen species (ROS), through the activation of the respiratory burst oxidase homologs (Rboh) genes, and trigger programmed cell death (PCD). The sequence of these events was demonstrated by manipulating the content of NO and ethylene in culture through pharmacological treatments. Collectively, our results illustrated that suppression of ZmPgb1.1 evokes tolerance against C. nebraskensis culminating in the execution of PCD, a key step of the hypersensitive response.

Lunar experiments: the moon as a site for certain physical measurements.

If the lunar surface becomes available for conducting physical experiments, it may be particularly suited to thermal neutron and molecular and atomic beam measurements. The application of these beams for the purpose of communication on the lunar surface appears possible.

Leukotriene D4: a potent coronary artery vasoconstrictor associated with impaired ventricular contraction.

Leukotriene D4 (2 c 10(-9) mole), injected into the left circumflex coronary artery of anesthetized sheep, produced profound coronary vasoconstriction and impaired regional ventricular wall motion. This cardiac effect was neither inhibited by prior treatment of the sheep with a cyclooxygenase inhibitor nor associated with thromboxane B2 release into the coronary sinus. Intravenous FPL 55712 completely abolished the coronary vasoconstriction of leukotriene D4, but a significant reduction of regional wall shortening persisted.

Seal lungs collapse during free diving: evidence from arterial nitrogen tensions.

Arterial blood nitrogen tensions of free-diving Weddell seals (Leptonychotes weddelli) were measured by attaching a microprocessor-controlled blood pump and drawing samples at depth to determine how these marine mammals dive to great depths and ascend rapidly without developing decompression sickness. Forty-seven samples of arterial blood were obtained from four Weddell seals during free dives lasting up to 23 minutes to depths of 230 meters beneath the sea ice of McMurdo Sound, Antarctica. Peak arterial blood nitrogen tensions of between 2000 and 2500 millimeters of mercury were recorded at depths of 40 to 80 meters during descent, indicating that the seal's lung collapses by 25 to 50 meters. Then arterial blood nitrogen tensions slowly decreased to about 1500 millimeters of mercury at the surface. In a single dive, alveolar collapse and redistribution of blood nitrogen allow the seal to avoid nitrogen narcosis and decompression sickness.

Mitochondrial Respiration and Hemoglobin Gene Expression in Barley Aleurone Tissue.

Previous studies have shown that plant hemoglobin (Hb) mRNA is expressed in barley (Hordeum vulgare L.) aleurone layers during hypoxia. We have examined the effect of a number of respiratory inhibitors on barley aleurone layers to determine the factors that influence Hb gene expression. Respiratory inhibitors that reduce O2 consumption, such as CO, cyanide, and antimycin A, strongly enhanced Hb mRNA levels. Treatment with the oxidative phosphorylation uncoupler 2,4-dinitrophenol markedly increased O2 consumption and had a similar positive effect on Hb gene expression. Hb transcript levels were also stimulated by the ATP synthase inhibitor oligomycin. The results suggest that the expression of Hb is not directly influenced by O2 usage or availability but is influenced by the availability of ATP in the tissue.

Abscisic Acid Structure-Activity Relationships in Barley Aleurone Layers and Protoplasts (Biological Activity of Optically Active, Oxygenated Abscisic Acid Analogs).

Optically active forms of abscisic acid (ABA) and their oxygenated metabolites were tested for their biological activity by examining the effects of the compounds on the reversal of gibberellic acid-induced [alpha]-amylase activity in barley (Hordeum vulgare cv Himalaya) aleurone layers and the induction of gene expression in barley aleurone protoplasts transformed with a chimeric construct containing the promoter region of an albumin storage protein gene. Promotion of the albumin storage protein gene response had a more strict stereochemical requirement for elicitation of an ABA response than inhibition of [alpha]-amylase gene expression. The naturally occurring stereoisomer of ABA and its metabolites were more effective at eliciting an ABA-like response. ABA showed the highest activity, followed by 7[prime]-hydroxyABA, with phaseic acid being the least active. Racemic 8[prime]-hydroxy-2[prime],3[prime]-dihydroABA, an analog of 8[prime]-hydroxyABA, was inactive, whereas racemic 2[prime],3[prime]-dihydroABA was as effective as ABA. The differences in response of the same tissue to the ABA enantiomers lead us to conclude that there exists more than one type of ABA receptor and/or multiple signal transduction pathways in barley aleurone tissue.

Mapping of antibody binding epitopes of a recombinant Poa p IX allergen.

Antibody binding epitopes of a recombinant Poa p IX allergen were delineated using recombinant DNA and solid-phase peptide synthesis procedures. The full-length cDNA clone KBG60 and its four overlapping recombinant fragments, KBG60.1, KBG60.2, KBG8.3 and KBG10 which spanned the entire molecule were synthesized in E. coli with aid of the plasmid expression vector, pWR590.1. The antigenic and allergenic sites of these recombinant proteins were analyzed by ELISA using human IgE and murine IgG antibodies. It was thus demonstrated that although the epitopes were found on all the fragments tested, the majority of these were located on a C-terminal fragment, rKBG8.3. Furthermore, synthetic peptides were also employed to identify the epitopes of rKBG60 protein. The use of antisera raised against native KBG pollen extract and the recombinant KBG8.3 protein to scan a total of 56 overlapping deca-penta peptides, covering the entire rKBG60 protein, revealed that 10 positive peptides involved in the antibody-binding site(s). Taken together, the results of these studies indicate that rKBG60 protein possesses at least 10 antibody binding epitopes.

Cloning and expression pattern of Hor v 9, the group 9 pollen isoallergen from barley.

In this study we report the cloning, sequence, and characterization of Hor v 9 allergen cDNAs from barley (Hordeum vulgare) pollen. Structural homologues of Kentucky bluegrass (Poa pratensis) group 9 pollen allergens were identified in a cDNA library of barley pollen expressed mRNAs. The Hor v 9 cDNA clone (hvp9742) contained an open reading frame encoding 313 amino acids which included a putative 27-residue signal peptide and one asparagine sequon for glycosylation. The mRNA corresponding to clone hvp9742 was produced abundantly in pollen during the late stages of anther development. The protein encoded by clone hvp974 was synthesized as a fusion protein in the E. coli expression vector pMAL. Immunoblots using antibodies to this recombinant allergen, rHor v 9, showed that Hor v 9 protein accumulated during pollen development and was produced maximally at pollen maturity. Using these antibodies, we also provide evidence that Hor v 9 protein localized to the extracellular matrix of mature pollen. Southern blots suggested that Hor v 9 allergens exist as multiple isoforms in barley. Sequence comparisons showed that the Hor v 9 cDNA clones were also homologous to group 5 allergens of Timothy grass (Phleum pratense) pollen and canary grass (Phalaris aquatica) pollen, and the group 9 allergen of ryegrass (Lolium perenne) pollen.

Very mild senile dementia of the Alzheimer type. II. Psychometric test performance.

A brief battery of psychometric tests was used to compare 41 individuals with very mild senile dementia of the Alzheimer type (SDAT) with 83 healthy participants and 66 individuals with mild SDAT. Although canonical analysis indicated that the same psychological functions (memory, speeded psychomotor performance, and language) are involved in both very mild and mild SDAT, objective levels of performance by the very mildly affected individuals overlapped extensively with those of both healthy aged and mildly demented individuals. Consideration of premorbid individual differences in psychological functions will probably be required if psychometric test performances are to be effective in detecting SDAT in the very mild stage.

Psychometric discrimination of moderate senile dementia of the Alzheimer type.

A brief psychometric battery was used to differentiate a sample of 56 individuals classified as having mild senile dementia of the Alzheimer type (SDAT) from 38 individuals with moderate SDAT. Using discriminant analysis techniques, a modest differentiation was obtained. It was noted that specific ability domains, namely, short-term recognition memory, visuospatial reasoning, and verbal ability, contributed to the discriminant function. Although the same domains have been found to differentiate SDAT at earlier stages, individual tests varied in the current sample as a function of marked decrements in ability levels at this advanced stage of the disease. The results suggest that the effectiveness of specific psychometrics for differentiating individuals with SDAT may vary as a function of relative disease stage.

Acid mine drainage and subsidence: effects of increased coal utilization.

The increases above 1975 levels for acid mine drainage and subsidence for the years 1985 and 2000 based on projections of current mining trends and the National Energy Plan are presented. No increases are projected for acid mine drainage from surface mines or waste since enforcement under present laws should control this problem. The increase in acid mine drainage from underground mines is projected to be 16 percent by 1985 and 10 percent by 2000. The smaller increase in 2000 over 1985 reflects the impact of the PL 95-87 abandoned mine program. Mine subsidence is projected to increase by 34 and 115 percent respectively for 1985 and 2000. This estimate assumes that subsidence will parallel the rate of underground coal production and that no new subsidence control measures are adopted to mitigate subsidence occurrence.

Determinants of functional abilities in dementia.

OBJECTIVES: To determine the extent to which selected variables within demographic, psychometric, and memory domains can predict functional abilities in dementia. DESIGN: Hierarchical regression analyses were employed to predict functional abilities, while controlling for disease severity, using the Mini-Mental State Exam (MMSE). SETTING AND PARTICIPANTS: A total of 2368 inhabitants of Kungsholmen parish in Stockholm, Sweden, aged 75 years of age or older. Eighty-one subjects with confirmed dementia (MMSE, M = 17.9; SD = 5.26) were selected from the study population. The mean age was 84.5 years (SD = 5.58), and 72% were female. MEASUREMENTS: Participants received a battery of standardized neuropsychological instruments and selected experimental tasks that measured visuospatial ability as well as primary and episodic memory. Self-care was assessed using the Katz index of activities of daily living (ADL); instrumental activities of daily living (IADL) were assessed through the primary caregiver, who responded to questions related to functional competence of the participant. RESULTS: Hierarchical regression procedures revealed that disease severity was the strongest predictor of ADL and IADL performance. Controlling for disease severity, a measure of visuoperception (Poppelreuter's figures) also made a significant contribution to the explanatory variance in both ADL and IADL function. Beyond disease severity and visuoperception, years of schooling and disease duration were marginally predictive of IADL performance. CONCLUSION: It is possible to predict functional abilities in dementia on the basis of individual difference variables. Multiple variables were initially correlated with ADL and IADL performance; however, after controlling for disease severity, visuoperception was the only predictor of ADL scores. In addition to visuoperception, IADL scores were also marginally predicted by education and disease duration. These findings highlight the importance of peripheral sensory processes in adaptive function in dementia. They also suggest that although many variables may be correlated with functional ability, their explanatory role, particularly with regard to self-care skills, is diminished in the presence of the disease.

Regional blood flow and pulmonary thromboxane release after sublethal endotoxin infusion in sheep.

Fifteen minutes after intravenous Escherichia coli endotoxin (EN) infusion the sheep lung transiently releases into the systemic circulation up to 12 micrograms of thromboxane A2 (TxA2)/min measured by radioimmunoassay as its metabolite thromboxane B2 (TxB2). To determine whether lung thromboxane release alters regional blood flow (RBF) we injected microspheres before and 20, 30, and 100 minutes after EN infusion in 13 awake sheep. In seven untreated control sheep (group 1) pulmonary vascular resistance (PVR) increased threefold at 20 and 30 minutes after EN infusion, coinciding with a large transpulmonary blood concentration gradient of TxB2. There was no measured RBF change to any systemic tissue or organ except the right ventricle at 20 minutes after EN infusion, when blood flow per gram of tissue doubled. In six sheep (group 2) treated with intravenous ibuprofen before EN infusion there was no increase in PVR, plasma TxB2, or blood flow to the right ventricle, and no difference of RBF to any other organ or tissue when compared to group 1. TxA2 is a potent local pulmonary vasoconstrictor but it rapidly hydrolyzes. Its short half-life and the circulatory delay in systemic arterial delivery prevent TxA2 from acting as a circulating vasoconstrictor.

Effects of leukotrienes B4 and C4 on coronary circulation and myocardial contractility.

Arachidonic acid is metabolized to prostaglandins and thromboxane via the cyclooxygenase pathway and to leukotrienes B4, C4, D4, and E4 via the lipooxygenase pathway. A possible role played by leukotrienes in cardiogenic shock resulting from anaphylaxis prompted us to investigate the action of these compounds on coronary vessels and myocardial contractility. In this study leukotriene B4 (LTB4) and C4 (LTC4) were injected directly into the left circumflex (LCx) coronary artery of nine anesthetized Suffolk sheep. LTB4 had no effect on coronary artery blood flow or myocardial contractility, but 3 X 10(-9) mole induced profound transient circulating neutropenia, reflecting the potent chemotactic and chemokinetic properties of this compound. Injecting as little as 1.6 X 10(-11) mole of LTC4 caused a 14.5 +/- 4.3% (mean +/- SE) reduction of LCx coronary artery flow while 1.6 X 10(-10) mole caused a 26.5 +/- 3.7% decrease of LCx coronary artery flow and an 18.1 +/- 3.2% decrease in systolic shortening of the myocardial region supplied by the LCx coronary artery. Since the decrease in systolic shortening was far greater than that expected on the basis of the reduction in coronary artery flow, we postulate that LTC4 has a direct negative inotropic effect. FPL 55712, a receptor antagonist of leukotrienes C4, D4, and E4, blocked the vasoconstriction induced by LTC4 but only partially blocked the negative inotropic effects of LTC4. LTC4 is a potent vasoconstrictor and negative inotropic agent and may play an important role in anaphylactic shock.

Episodic memory and visuospatial ability in detecting and staging dementia in a community-based sample of very old adults.

BACKGROUND: This study examined the efficacy of a cognitive test battery in detecting and staging dementia in a community-based sample of very old adults. METHOD: The sample consisted of 398 nondemented and 108 demented adults taken from all the inhabitants in the Kungsholmen parish of Stockholm, Sweden (2,368 individuals), aged 75 years and older, who were part of a large-scale epidemiological study on aging and dementia. Participants received a cognitive test battery that consisted of specialized episodic memory tasks, as well as standardized psychometric measures of visuospatial ability and primary memory. RESULTS: A discriminant analysis revealed that highly supported episodic memory tasks (recognition, cued recall) were primarily responsible for correctly classifying normal old adults (94.5%) from those with the diagnosis of dementia (66.7%). Using the Mini-Mental State Exam (MMSE) as the criterion of dementia severity, a correct classification of 88.9% was achieved for mildly demented subjects and 77.8% for moderately demented subjects. Visuospatial tasks made the greatest contribution in distinguishing those at different levels of dementia severity. CONCLUSION: The results of this investigation indicate that cognitively supported measures assessing episodic memory may be particularly useful in the detection of dementia, whereas visuospatial measures are more effective in staging the disease. Consistent with biological models of the progression of dementia, this suggests that visuospatial abilities may deteriorate later and/or at a slower rate than episodic memory skills in the early stages of dementia. It is noteworthy that these conclusions are based on samples of very old adults taken from the general population.

Microcomputer monitor and blood sampler for free-diving Weddell seals.

The equipment used for the first sampling of arterial blood at depth on free-diving Weddell seals Leptonychotes weddelli is described. Blood was withdrawn through an aortic catheter by a submersible, peristaltic roller pump and stored in a single- or multiple-sample collection device. The multiple sampler allowed up to eight individual blood samples to be collected during a single dive. The blood pump was controlled by a dedicated microcomputer that allowed initiation of blood sampling at flexible combinations of depth and/or time during either the descending or ascending phase of the dive. The dedicated microcomputer also recorded swimming depth, velocity, heart rate, and body temperature at selectable time intervals. These data were transmitted to a laboratory computer, and blood samples were retrieved, when the seal surfaced to breathe.

Hemoglobin concentrations and blood gas tensions of free-diving Weddell seals.

Arterial blood gas tensions, pH, and hemoglobin concentrations were measured in four free-diving Weddell seals Leptonychotes weddelli. A microprocessor-controlled sampling system enabled us to obtain 24 single and 31 serial aortic blood samples. The arterial O2 tension (PaO2) at rest [78 +/- 13 (SD) Torr] increased with diving compression to a maximum measured value of 232 Torr and then rapidly decreased to 25-35 Torr. The lowest diving PaO2 we measured was 18 Torr just before the seal surfaced from a 27-min dive. A consistent increase of arterial hemoglobin concentrations from 15.1 +/- 1.10 to 22.4 +/- 1.41 g/100 ml (dives less than 17 min) and to 25.4 +/- 0.79 g/100 ml (dives greater than 17 min) occurred during each dive. We suggest that an extension of the sympathetic outflow of the diving reflex possibly caused profound contraction of the Weddell seal's very large spleen (0.89% of body wt at autopsy), although we have no direct evidence. This contraction may have injected large quantities of red blood cells (2/3 of the total) into the seal's central circulation during diving and allowed arterial O2 content to remain constant for the first 15-18 min of long dives. The increase of arterial CO2 tensions during the dive and the compression increase of arterial N2 tensions were also moderated by injecting red blood cells sequestered at ambient pressure. After each dive circulating red blood cells are oxygenated and rapidly sequestered, possibly in the spleen during the first 15 min of recovery.

Efficacy of self-help behavior modification materials in smoking cessation.

We evaluated the efficacy of the Stanford Quit Kit, an eight-page self-administered smoking cessation program. Subjects were randomly assigned to receive the Quit Kit (n = 142) or a delayed intervention (n = 65). Confirmed abstinence (p less than .05) and reduced smoking among continuing smokers (p less than .002) were greater in the Quit Kit group than in the control group at the two-month follow-up. At the six-month follow-up 10.6 percent of the Quit Kit subjects were confirmed as abstinent. From these results we conclude that well-designed, self-administered behavior change materials can assist chronic smokers in quitting.

The influence of depressive symptomatology on episodic memory functioning among clinically nondepressed older adults.

The authors examined a community-based sample of 303 clinically nondepressed individuals aged 75 through 96 years on 4 recall tasks: free recall of rapidly presented random words, free recall of slowly presented random words, free recall of organizable words, and cued recall of organizable words. Using a classification taxonomy that identified mood- and motivation-related symptoms of depression, it was found that motivation-related symptoms had a negative effect on performance across all tasks, whereas mood-related symptoms had no effects. In addition, motivation-related symptoms negatively influenced the ability to benefit from more study time but had no effect on the ability to make use of item organization or category cues. An analysis of the specific motivation-related symptoms suggested that symptoms that may affect the ability to focus and sustain attention (e.g., concentration difficulties, lack of interest) were most strongly associated with performance deficits.

Nonsymbiotic haemoglobins in plants.

General aspects regarding the presence of nonsymbiotic haemoglobin in plants are presented with the emphasis on those related to its function. As it becomes apparent that the nonsymbiotic haemoglobins are widespread across the plant kingdom and that they represent a more primitive and evolutionary older form of the plant globin genes, the question of their function becomes more attractive. While the physiological functions of the symbiotic haemoglobins in plants are well understood, almost nothing is known about their nonsymbiotic predecessors. Therefore, the known and hypothetical functions of haemoglobins in various systems are described along with information concerning properties and the regulation of expression of the nonsymbiotic haemoglobins. Interestingly, a number of nonsymbiotic haemoglobins have been shown to be hypoxia-inducible. The spatial and temporal pattern of this induction in barley may suggest that it is an integral part of the plants response to limiting oxygen stress.