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M J Jaffe

Publications and source records attributed to M J Jaffe.

At least 37 records · Page 2Linked to original sources
PubMed1985

Computer-assisted image analysis of plant growth, thigmomorphogenesis and gravitropism.

A nonintrusive auxonometric system, based on the DARWIN image processor (Telewski et al. 1983 Plant Physiol 72: 177-181), is described and demonstrated in the analysis of gravitropism and thigmomorphogenesis in corn seedlings (Zea mays). Using this system, growth and bending of regularly shaped plants or organs can be quickly and accurately measured without, in any way, interfering with the plant. Furthermore, the growth and bending curves are automatically plotted. Thigmomorphogenesis in the aerial part of corn seedlings involves growth promotion at a low force load and growth retardation at higher force loads. The time courses of the two kinds of response are somewhat different, with retardation occurring immediately after mechanical perturbation and growth promotion taking somewhat longer to begin. Gravitropic experiments show that when dark-grown corn seedlings are placed on their side in the light, the resulting curvature is due to two consecutive morphological mechanisms. In the first instance, lasting for about 15 minutes, the elongation of the bottom edge of the plant accelerates, while the elongation of the top edge remains constant. After that, for the next 1.75 hours, the elongation of the top edge decelerates and stops while that of the bottom edge remains constant at the increased rate for most of the period. The measurements taken from both experiments at relatively high resolution (0.08-0.1 millimeter) show that the growth curves are not smooth but show many small irregularities which may or may not involve micronutations.

Evaluation Studies as Topic↗
PubMed1984

Spatial contrast sensitivity. Importance of controlling the patient's visibility criterion.

Clinical spatial contrast sensitivity measurements are typically made using psychophysical methods that do not specify the response criterion being used by the patient in judging grating visibility. Results of this report show the necessity of such methods for (1) maximizing detectability of early contrast sensitivity deficits by minimizing normal sample variance, and (2) ensuring that changes in an individual's contrast sensitivity reflect changes in vision and not simply fluctuations in the patient's criterion for judging grating visibility.

Adult↗
PubMed1984

Callose deposition during gravitropism of Zea mays and Pisum sativum and its inhibition by 2-deoxy-D-glucose.

In etiolated corn (Zea mays L.) and etiolated pea (Pisum sativum L.) seedlings, a gravitropic stimulation induces the deposition of callose. In the corn coleoptiles this occurs within 5 min of gravity stimulation, and prior to the beginning of curvature. Both gravitropic curvature and callose deposition reach their maxima by 12 h. Within the first 2 h more callose is deposited on the upper (concave) side, but after 2-3 h, this deposition pattern is reversed. An inhibitor of protein glycosylation, 2-deoxy-D-glucose (DDG), inhibits callose production and considerably retards gravitropic bending in both species of plants. Mannose can relieve the inhibition of gravitropic bending by DDG. The pea mutant "Ageotropum", which does not respond to gravity when etiolated, also fails to produce callose in response to a gravitic stimulus. These correlations indicate that callose deposition may be a biochemical component of gravitropism in plant shoots.

Deoxyglucose↗
PubMed1984

Imaging of urinary tract disease. Current approaches.

Current modalities and techniques used in imaging of the urinary tract offer prompt and accurate diagnoses as well as treatment in some cases. Careful planning and judgement in the choice of the imaging sequence is important in avoiding redundant or ill-advised tests. Individual tailoring will be necessary in some patients. It is hoped that with the rational use of the diagnostic tools now available and with the continued improvement in MRI technology, safe and accurate diagnoses will be expected in practically all patients with diseases of the urinary tract.

Abscess↗
PubMed1984

Physiological Studies on Pea Tendrils : XIV. Effects of Mechanical Perturbation, Light, and 2-Deoxy-d-Glucose on Callose Deposition and Tendril Coiling.

When excised tendrils of pea (Pisum sativum L. cv Alaska) are mechanically perturbed there is an immediate and transient increase in callose deposition in the sieve cells. Mechanical perturbation (MP) results in a coiling response in light-grown tendrils and in dark-adapted tendrils, provided, in the latter case, that they receive adequate illumination within a limited period of time after MP. In nonperturbed tendrils the number of callose deposits decreases to some minimum with increasing time in the dark, and their ability to coil in the dark in response to MP diminishes with time in the dark. The transient increase of callose deposition due to MP, however, occurs whether or not tendrils are dark adapted, and whether they receive light or are retained in the dark after MP. This indicates that if callose is directly involved in tendril coiling, then it exerts its effect on the sensory perception of the mechanical stimulus. In the present investigation, there is never tendril coiling without the transient increase in callose, and the time after MP at which the peak of callose deposition occurs precedes the time of the peak amount of coiling.An inhibitor of callose formation, 2-deoxy-d-glucose (DDG), is equally effective at inhibiting tendril coiling and MP-induced callose deposition, indicating, within the limitations of the specificity of DDG, that callose deposition may be required in order for the coiling response to occur. Alternatively, DDG may prevent the availability of some other factor necessary for tendril coiling.

Journal Article↗
PubMed1984

Thigmomorphogenesis: on the mechanical properties of mechanically perturbed bean plants.

The mechanical properties of control and mechanically perturbed (MP) bean stems (Phaseolus vulgaris L., cv. Cherokee wax) were compared. The rubbed plants were greatly hardened against mechanical rupture by previous MP. This hardening was due to a dramatic increase in the flexibility of the stems, but not in their stiffness. The MP-plants were able to bend more than 90 degree without breaking, whereas the control plants broke after just slight bending. A comparison with other work reveals that different species utilize different tactics for achieving similar resistance to rupture due to mechanical stress.

Biomechanical Phenomena↗
PubMed1984

Thigmomorphogenesis: the relationship of mechanical perturbation to elicitor-like activity and ethylene production.

An extracellular solution obtained from bean (Phaseolus vulgaris L. cv. Resistant Cherokee Wax) stems induced phytoalexin-like substance and ethylene production in a soybean [Glycine max (L.) Merr. cv. Wayne] cotyledon bioassay. The elicitor-like activity for phytoalexin formation and ethylene production was increased by mechanical perturbation of bean stems. Moreover, the application of extracted or known elicitors to bean plants mimicked the effect of mechanical perturbation (i.e., inhibition of stem elongation and enhancement of radial growth). The effects of extract when applied exogenously, on elicitor-like activity in the bioassay as well as stem thickening were decreased by aminoethoxyvinylglycine, an inhibitor of ethylene biosynthesis. These results suggest that elicitor-like substances which are formed in response to mechanical perturbation contribute to the thigmomorphogenesis.

Amino Acids↗
PubMed1984

Hyperprolactinemia, amenorrhea, and galactorrhea. A retrospective assessment of twenty-five cases.

The syndrome of hyperprolactinemia, galactorrhea, and amenorrhea is frequently caused by a pituitary tumor. Transsphenoidal surgical removal is often advocated for microadenomas, tumors smaller than 10 mm, to prevent the progression of these small adenomas into large tumors. Because no strong evidence indicates that microadenomas naturally progress to macroadenomas, we studied 25 women who had had hyperprolactinemia, amenorrhea, or galactorrhea for a mean duration of 11.3 years. Their mean initial prolactin level was 225 ng/mL (normal, less than 36 ng/mL). Of 22 patients presenting with amenorrhea, 7 resumed menses spontaneously. Galactorrhea resolved completely in 6 of the 19 patients with this disorder. Only 1 patient had progression of a sellar abnormality, and this was slight. Visual fields remained full in all patients, and basal adrenal and thyroid functions remained normal. The mean prolactin level was 155 ng/mL at the reevaluation (p less than 0.01, initial versus reevaluation levels). Hyperprolactinemia apparently has a benign clinical course in most women, and we advocate a conservative approach to management of this disorder.

Adenoma↗
PubMed1984

Further studies of auxin and ACC induced feminization in the cucumber plant using ethylene inhibitors.

The present study was designed to establish the role of an essential hormone controlling sex expression in cucumber. A potent anti-ethylene agent, AgNO3, completely inhibited pistillate flower formation caused by IAA, ACC or ethephon. Inhibitors of ethylene biosynthesis, AVG and CoCl2 also suppressed feminization due to exogenous IAA or ACC. Though AVG also suppressed ethephon-induced feminization, this may be due to the second effect of AVG rather than the effect on ACC biosynthesis. These results confirm that ethylene is a major factor regulating feminization and that exogenous auxin induces pistillate flower formation through its stimulation of ethylene production, rather than ACC production.

Amino Acids↗
PubMed1984

Pithiness in plants: I. The effect of mechanical perturbation and the involvement of ethylene in petiole pithiness in celery.

Mechanical perturbation (MP) applied to celery (Appium graveolens L. cv. Florida 683) leaf petioles or ethephon application to the plant did not induce thigmomorphogenesis (inhibition of elongation and increase in thickness of the petiole). However, the two treatments did cause the parenchyma breakdown which leads to pithiness or increased natural pithiness, mainly at the base of the petiole. Nevertheless, MP (but not ethephon) decreased the severity of drought-stress or GA3-induced pithiness. Although MP stimulates ethylene production, mainly at the middle part of the petiole, it seems that the protection by MP of the petiole may not be directly mediated by ethylene production. The exposure of the plant to drought stress brought about an increase in ethylene evolution. Upon reirrigating the plants, the first steps of pithiness were accompanied by a sharp decline in ethylene production. This decrease might be due to membrane disruption. The increase in ethylene production during drought stress may be one of the events which stimulate pithiness of the celery leaf petiole.

Apiaceae↗
PubMed1983

Computer-Assisted Image Analysis of Tissues of Ethrel-Treated Pinus taeda Seedlings.

A microcomputer based video image analyzer is described and demonstrated in the analysis and comparison of tissue types of 6-month-old Ethrel-treated and control seedlings of loblolly pine (Pinus taeda L.). Two different programs were employed. ;Topographer I' sought, identified, and measured cell or resin canal lumen areas, and ;Area' measured tracheid length and silhouette areas. Ethrel treatment induced an increase in radial growth and a decrease in shoot elongation and needle growth. Bark production was stimulated by the same treatment. The tracheid lumens of Ethrel-treated plants were shorter and had a smaller cross-sectional area, whereas the tracheid cell walls increased in thickness. The treatment also increased resin canal formation in the xylem.

Journal Article↗
PubMed1979

Hemodynamics and metabolism of the in vivo vascularly isolated canine pancreas.

Surgical procedures are detailed that have yielded for the first time an in vivo vascularly isolated, autoperfused preparation of the entire pancreas in anesthetized dogs. Previous studies had isolated only part of the pancreas or had resorted to blood-flow techniques not requiring pooled pancreatic venous blood, necessary for metabolic studies of the organ. Pancreatic blood flow (48 ml/min), O2 uptake (180 mumol/min), glucose uptake (51.0 mumol/min), lactate output (6.6 mumol/min), net free fatty acid uptake (2.23 mumol/min), all per 100 g tissue, and various other measured and calculated hemodynamic and metabolic variables were determined on the preparation during control conditions. The stability of the preparation was verified by serial determinations of these parameters and of blood alpha-amylase and beta-glucuronidase levels from 1 to 2.5 h postsurgery. Metabolic rate and glucose uptake were both found to be much higher than in intestinal tissues and approached values characteristic of liver tissue.

Animals↗
PubMed1975

Cholinesterases from plant tissues. VI. Preliminary characterization of enzymes from Solanum melongena L. and Zea mays L.

Enzymes capable of hydrolyzing esters of thiocholine have been assayed in extracts of Solanum melongena L. (eggplant) and Zea Mays L. (corn). The enzymes from both species are inhibited by the anti-cholinesterases neostigmine, physostigmine, and 284c51 and by AMO-1618, a plant growth retardant and they both have pH optima near pH 8.0. The enzyme from eggplant is maximally active at a substrate concentration of 0.15 mM acetylthiocholine and is inhibited at higher substrate concentrations. On the basis of this last property, the magnitude of inhibition by the various inhibitors, and the substrate specificity, we conclude that the enzyme from eggplant, but not that from corn, is a cholinesterase.

Acetylthiocholine↗
PubMed1974

Cholinesterases from Plant Tissues: III. Distribution and Subcellular Localization in Phaseolus aureus Roxb.

The distribution and localization of cholinesterase in Phaseolus aureus, Glycine max, and Pisum sativum is described. The enzyme is present in roots, leaves, stems, root callus tissue, root cells suspension cultures, and root nodules. Cholinesterase in roots is found primarily in the cell wall. In cell fractionation experiments, at least 95% of the cholinesterase activity is associated with cell wall material. The enzyme can be solubilized by salt solutions, whereas Triton X-100 and sodium deoxycholate solubilize relatively small amounts of the enzyme. Cytochemical techniques have been employed to show the presence of cholinesterase activity at the cell surface and in the cell wall of certain cells of the root.

Journal Article↗
PubMed1974

Cholinesterases from plant tissue: v. Cholinesterase is not pectin esterase.

Several properties of the cholinesterase from Phaseolus aureus Roxb. and of pectin (methyl) esterases from both Phaseolus aureus and Lycopersicon esculentum (L.) Mill. are contrasted. Cholinesterase activity is inhibited by all of the concentrations of NaCl tested, from 0.05 m to 0.9 m, a property which differs sharply from published data pertaining to pectin esterase. Although crude preparations of cholinesterase contain pectin esterase activity, further purification by gel filtration of the cholinesterase results in a nearly complete elimination of the pectin esterase activity. The activity of neither the pectin esterase from Lycopersicon esculentum nor that from Phaseolus aureus is affected by 25 mum neostigmine, a potent inhibitor of the cholinesterase activity extracted from Phaseolus aureus.

Journal Article↗
PubMed1973

The Role of ATP in Mechanically Stimulated Rapid Closure of the Venus's Flytrap.

When the midribs of untreated traps of Dionaea muscipula are frozen in liquid nitrogen after rapid closure, they contain significantly less ATP than those frozen before closure. Exogenous ATP causes a significant increase in the rate of mechanically stimulated trap closure. Illuminated traps close faster than those kept in the dark. The traps of plants placed in 100% O(2) close much faster than do air controls, while 100% CO(2) inhibits closure. It is concluded that ATP is probably the native source of potential energy for contraction of the trap's midrib, and that if the endogenous ATP titer is increased by oxidative phosphorylation or an exogenous source, the trap will close faster.

Journal Article↗