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 immeditely 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.     

Chlorophyll differences in Mono Lake (California) observable on Landsat imagery

In Mono Lake (California), a large saline lake, chlorophyll concentrations in the euphotic zone increased from 4 to 45 µg l^–1 between July and October 1979. These seasonal changes in chlorophyll are detectable on imagery obtained with the multispectral scanner on Landsat. Computer-compatible tapes of Landsat images were normalized for solar zenith and corrected for atmospheric scatter and absorption to obtain Landsat band 4 emittances (W m^–2 str^–1) of 13.4 ± 0.5 when chlorophyll was 4 µg l^–1 and 4.6 ± 0.3 when chlorophyll was 45 µg l^–1. Lake wide, spatial heterogeneity of chlorophyll of 2 µg l^–1 in July and 8 µg l^–1 in October was not detectable on the Landsat imagery.     

Calcium-Stimulated Proteolysis in Myelin: Evidence for a Ca2+-Activated Neutral Proteinase Associated with Purified Myelin of Rat CNS

Incubation of myelin purified from rat spinal cord with CaCl2 (1-5 mM) in 10-50 mM Tris-HCl buffer at pH 7.6 containing 2 mM dithiothreitol resulted in the loss of both the large and small myelin basic proteins (MBPs), whereas incubation of myelin with Triton X-100 (0.25-0.5%) and 5 mM EGTA in the absence of calcium produced preferential extensive loss of proteolipid protein (PLP) relative to MBP. Inclusion of CaCl2 but not EGTA in the medium containing Triton X-100 enhanced degradation of both PLP and MBPs. The Ca2+-activated neutral proteinase (CANP) activity is inhibited by EGTA (5 mM) and partially inhibited by leupeptin and/or E-64c. CANP is active at pH 5.5-9.0, with the optimum at 7-8. The threshold of Ca2+ activation is approximately 100 microM. The 150K neurofilament protein (NFP) was progressively degraded when incubated with purified myelin in the presence of Ca2+. These results indicate that purified myelin is associated with and/or contains a CANP whose substrates include MBP, PLP, and 150K NFP. The degradation of PLP (trypsin-resistant) in the presence of detergent suggests either release of enzyme from membrane and/or structural alteration in the protein molecule rendering it accessible to proteolysis. The myelin-associated CANP may be important not only in the turnover of myelin proteins but also in myelin breakdown in brain diseases.     

Antifungal therapy of dermatophytosis in guinea pigs and congenitally athymic rats

Guinea pigs and athymic nude (RNU/RNU) rats were used to assess the efficacy of three orally administered antifungal agents — Tolciclate, Tolnaftate, and Ketoconazole — against Trichophyton mentagrophytes dermatophytosis. All three antifungal agents inhibited the test strain of T. mentagrophytes in vitro. Antifungal agents were tested in intervention (oral therapy started 5 days after challenge) or prophylaxis (oral therapy started 5 days before challenge) protocols. Oral treatment of dermatophytosis on guinea pig skin demonstrated that Tolciclate and Tolnaftate alleviated clinical symptoms and shortened the duration of the dermatophytosis, in comparison to nontreated controls. Assessment of antifungal efficacy in the guinea pig model was time consuming (30–35 days) and variability in the duration and severity of clinical symptoms on guinea pig skin was common.Oral therapy of chronically infected athymic rats demonstrated that Tolciclate, Tolnaftate, and Ketoconazole were effective antifungal agents in vivo. Obvious improvement in clinical symptoms of dermatophytosis (i.e. less erythema and fewer lesions) was evident with all three antifungal agents within 10 days of starting oral therapy. By day 20, athymic rats that were treated with either Tolciclate or Ketoconazole showed marked clinical improvement of the chronic dermatophytosis.Chronically infected athymic rats, which lack thymus matured T-cells, are a promising new model to evaluate the efficacy of antifungal agents by culture, histology, and visual observations of clinical symptoms.     

The use of catheter-tipped pressure transducers for chronic measurement of genital tract pressures in the ewe. I. Implantation technique, catheter performance and data analysis

A computerised system for chronic in vivo monitoring of genital tract pressure in the ewe is described. Solid-state, catheter-tipped pressure transducers were surgically implanted in the uterine tube (ampulla), ipsilateral uterine horn and abdomen of five non-pregnant parous ewes. The catheters were connected to a portable computer which recorded the pressure at each location once per second and was programmed to analyse the data as mean pressure and area under the contraction curve over given periods. The catheters remained implanted for up to 129 days and 252 daily recordings were made. Analysis of spontaneous activity showed little variation in mean pressure of work done over four successive ten-minute periods. Although the amplitude of uterine contractions varied quite dramatically, chiefly in relation to variation in the plasma progesterone concentration, ampullary activity was unaffected by such changes. Genital tract pressures did not appear to be influenced by abdominal events. The catheters provoked minimal tissue reaction, and it is suggested that the system is suitable for chronic in vivo recording of genital tract pressure in the ewe.     

Reduction in headache patients' medical expenses associated with biofeedback and relaxation treatments

Comparisons are made of self-reported medical costs from a sample of headache patients who underwent various combinations of relaxation training and biofeedback training. The average costs for the 2 years prior to self-regulatory treatment were $955±480 (3 SEM) for 45 patients; for the 2 years after completing treatment the average costs were $52±28 (3 SEM) for patients. Within the limitations of the study, medical costs do seem to have been markedly reduced.This research was supported by a grant from NINCDS, NS-15235.     

Effect of indomethacin on proteinuria in rats with autologous immune complex nephropathy

Although non-steroidal anti-inflammatory agents have been used to reduce levels of urinary protein excretion in patients with the nephrotic syndrome, the general usefulness of these drugs in proteinuric states remains unclear. The present study was designed to confirm the efficacy and to investigate some of the mechanism/s of action of non-steroidal anti-inflammatory agents in animals with proteinuria as the result of a single form experimental renal disease. Autologous immune complex nephropathy was produced in groups of Lewis rats by the administration of autologous tubular F×1A antigen. After marked proteinuria developed, indomethacin (8 mg/kg/day) was administered orally to one group of animals for five days while a control group received only vehicle. The level of urinary protein excretion in the indomethacin treated animals was 420 ± 198 mg/day compared to a level of 1180 ± 306 seen in the untreated animals (p < 0.05). When the indomethacin-treated and control animals were compared, the reduction in proteinuria could not be found to be associated with a change in the glomerular filtration rate, urine electrolyte or osmolar excretion rates, electron microscopic appearance of the glomerular basement membrane, or a change in the glomerular permeability to neutral dextran. Treatment of animals with either sodium salicylate or lower doses of indomethacin (both of which resulted also in significant falls in urinary prostaglandin E excretion rates) failed to reduce the levels of proteinuria. Thus, indomethacin was capable of reducing the levels of protein excretion in rats with autologous immune complex nephropathy although the mechanism of action of this agent remains unclear.     

Effects of phorbol myristate acetate,phorbol dibutyrate,ethanol, dimethylsulfoxide,phenol, and seven metabolities of phenol on metabolic cooperation between chinese hamster v79 lung fibroblasts

The effect of phorbol myristate acetate, phorbol dibutyrate, ethanol, dimethylsulfoxide, phenol, and seven metabolites of phenol on metabolic cooperation were assessed as a function of mutant cell recovery from populations of cocultivated hypoxanthine-guanine phosphoribosyl transferase-deficient mutant (HGPRT–) and wild-type (HGPRT+) Chinese hamster V79 lung fibroblasts. Phorbol myristate acetate and phorbol diputyrate, two established tumor promoters, were potent inhibitors of metabolic cooperation. Ethanol and dimethylsulfoxide, solvents commonly used to prepare chemicals for testing, weakly inhibited metabolic cooperation. Phenol and phenylglucuronide had no effect on metabolic cooperation. Four oxidative metabolites (1,4-benzoquinone, catechol, hydroxyquinol and quinol) inhibited metabolic cooperation. Phenylsulfate weakly inhibited metabolic cooperation. Conversely, 2-methoxyphenol, a methylated derivative of catechol, appeared to enhance metabolic cooperation. These results generallyAbbreviations CAS Chemical Abstracts Service - DMSO dimethylsulfoxide - ETOH ethanol - HGPRT hypoxanthine-guanine phosphoribosyl transferase - HGPRT+ HGPRT-competent - HGPRT– HGPRT-te]deficient - MC metabolic cooperation - MC+ metabolic cooperation-competent - MC– metabolic cooperation-deficient - MEM minimum essential medium - PDBu phorbol dibutyrate - PMA phorbol myristate acetate - 6TG 6-thioguanine - 6TG^r 6-thioguanine-resistant - 6TG^s 6-thioguanine-sensitive - V79/MC assay Chinese hamster V79 lung fibroblast assay for metabolic cooperation     

Foliar flavonoid aglycones of Phoebanthus

The diploid Phoebanthus tenuifolius and the tetraploid P. grandiflorus yielded identical complements of foliar flavonoid aglycones, including the compounds nepetin, jaceosidin, and hymenoxin. Flavonoid data do not resolve the origin of the tetraploid species. The similarity between the flavonoids of Phoebanthus and those earlier reported for Helianthus would support a merger of the two genera.