Effect of bitter gourd and spent turmeric on constituents of glycosaminoglycans in different tissues in streptozotocin induced diabetic rats

Diet is now one of the well established means in the management of diabetes. Bitter gourd and spent turmeric at 10% level were tested for their efficacy on glycosaminoglycan metabolism in various tissues viz., liver, spleen, lungs, heart and testis in control, diabetic and treated rats. The glycosaminoglycans (GAGs) were isolated from defatted and dried tissues. The contents of sulfated GAGs decreased in all the tissues and the decrease was more prominent in heart and testis. In the isolated GAGs, contents of total sugar, amino sugar, uronic acid and sulfate were studied. Decrease in total sugar content was maximum in testis. Amino sugar content decreased considerably in testis (38%) and lungs (15%). The content of uronic acid also decreased in testis (33%) besides heart (29%) and liver (25%). Sulfate groups in GAGs perform pivotal functions in many biological events and decrease in sulfate content was significant in heart (40%), testis (37%) and liver (37%). GAGs profile on the cellulose acetate electrophoresis revealed that heparan sulfate (HS), hyaluronic acid (HA) and chondroitin sulfate/dermatan sulfate (CS/DS) were present in liver, spleen and lungs. HS, CS were present in heart, DS/CS was observed in testis. The observed beneficial effects in GAGs metabolism during diabetes may be due to the presence of high amounts of dietary fibres present in bitter gourd and spent turmeric, besides, possible presence of bioactive compounds in one or both of them.     

Novel<Emphasis Type="Italic"> eceriferum</Emphasis> mutants in<Emphasis Type="Italic"> Arabidopsis thaliana</Emphasis>

We conducted a novel non-visual screen for cuticular wax mutants in Arabidopsis thaliana (L.) Heynh. Using gas chromatography we screened over 1,200 ethyl methane sulfonate (EMS)-mutagenized lines for alterations in the major A. thaliana wild-type stem cuticular chemicals. Five lines showed distinct differences from the wild type and were further analyzed by gas chromatography and scanning electron microscopy. The five mutants were mapped to specific chromosome locations and tested for allelism with other wax mutant loci mapping to the same region. Toward this end, the mapping of the cuticular wax (cer) mutants cer10 to cer20 was conducted to allow more efficient allelism tests with newly identified lines. From these five lines, we have identified three mutants defining novel genes that have been designated CER22, CER23, and CER24. Detailed stem and leaf chemistry has allowed us to place these novel mutants in specific steps of the cuticular wax biosynthetic pathway and to make hypotheses about the function of their gene products.Abbreviations EMS Ethyl methane sulfonate - SEM Scanning electron microscopy - SSLP Simple sequence length polymorphism - WT Wild type     

Leaf surface properties of Norway spruce needles exposed to sulphur dioxide and ozone in an open-air fumigation system at Liphook

Samples of current-year and 1-year-old foliage were taken from Norway spruce (Picea abies (L.) Karst.) trees in April 1991, 4 months after a 3–4 year controlled fumigation with O₃ and SO₂ in the open at Liphook, south-east England. Trees were grown in seven plots, and treated in a factorial design with three levels of SO₂ and two levels of O₃ (ambient and c. 1.3 × ambient), with an extra ambient air plot. All statistical analyses were made on plot means. Leaf wettability, as measured by the contact angle of water droplets, was significantly affected by needle age and by SO₂ treatment (P≤0–05. in older needles, decreasing with increasing SO₂ concentration. There was no effect of O₃ on wettability, and no effect of any treatment on amounts of surface wax extracted by immersion of needles in chloroform. Electrolyte leakage rates from detached current-year needles were not affected by prior exposure to O₃, but decreased significantly (P= 0.034) with increasing exposure to SO₂. There was no detectable effect of fumigation on the rate of water loss from detached needles. Similarly, there was no effect of fumigation on the dry weight/fresh weight ratio of needles. The total sulphur content of needles increased significantly (P≤0.0001) with exposure to SO₂ and with needle age. Amounts of water-extractable sulphate, however, varied greatly among plots, but with no pattern with respect to fumigation treatment. It is concluded that leaf wettability and electrolyte leakage rates may be good indicators of the persistent effects of SO₂ on Norway spruce growing in the open air, and that the observed changes in leaf surface properties in response to SO₂ fumigation have implications for the processes, both biotic and abiotic, that occur on leaf surfaces.     

Leaf surface waxbloom in Pisum sativum influences predation and intra-guild interactions involving two predator species

Suppression of shared prey populations by insect predators can be influenced by interactions among these predators (intra-guild interactions). Intra-guild interactions among predators attacking herbivores may be influenced by plant characteristics, but this possibility has not been examined. Plant surface waxes are a ubiquitous and variable morphological feature that are known to affect insect predator behavior, and potentially in- fluence inter-predator interactions. To test this possibility we measured the effectiveness of individual and multiple predators on Pisum sativum L. lines with either wild-type crystalline waxes (normal waxbloom) or with reduced waxbloom resulting from a genetic mutation. On caged five-node plants of each line, reduction in populations of Acyrthosiphon pisum (Harris) (Homoptera: Aphidae) by individuals or pairs of second-instar Hippodamia con- vergens Guerin de Meneville (Coleoptera: Coccinellidae), and second-instar Chrysoperla plorabunda (Fitch) (Neuroptera: Chrysopidae), was significantly greater on the reduced waxbloom plants. Intra-specific interference by H. convergens depended on plant waxbloom type. Pairs of H. convergens larvae were no more effective than individuals of this species at reducing aphid populations on normal waxbloom plants, indicating interference, but were additive in their reduction of aphids on reduced waxbloom plants, indicating no interference. In contrast, pairs of C. plorabunda apparently interfered regardless of plant waxbloom type; pairs were no more effective at reducing aphids than individuals of this species. Heterospecific pairs of H. convergens and C. plorabunda were more effective on reduced waxbloom plants and showed no evidence of interference on either waxbloom type. Differences in behavior of the two predator species provided a partial explanation for the asymmetrical effect on intraspecific interactions in the two species. H. conver- gens spent significantly more time walking and less time ”scrambling” (ineffective locomotion) on reduced waxbloom plants than on normal waxbloom plants, and distributed these activities differently among plant parts on the two waxbloom types. In contrast, C. plorabunda spent the same amount of time walking and scrambling on each waxbloom type, although they distributed this walking and scrambling differently among plant parts of the two waxbloom types. The stronger influence of plant waxbloom on H. convergens behavior is consistent with the difference in intra-specific interference for this species on the two waxbloom types. The mechanisms of intra-specific interference by H. convergens on normal waxbloom plants and by C. plorabunda on both waxbloom types were not determined. Received: 14 July 1999 / Accepted: 10 January 2000     

Screening the ability of rice roots to overcome the mechanical impedance of wax layers: importance of test conditions and measurement criteria

The development of a wax layer method for screening the ability of rice (Oryza sativa L.) roots to overcome mechanical impedance is described. Wax layers (3 mm thick) made of mixtures of white soft paraffin and paraffin wax were installed 50 mm deep in tubes of sand. The sand was watered with nutrient solution and planted with 3-d old rice seedlings. The numbers of root axes per plant that had penetrated the wax layers 24 d after planting were counted. The ratio of penetrated to total root axes per plant gave a misleading measure of root penetration ability, as rice varieties differed in the ratio of penetrated to total axes in a low impedance (3% wax) control. In non-flooded conditions, a 60% wax layer decreased root penetration (number of roots penetrating the wax layer per plant) to a mean of 74% of the low impedance control, whereas an 80% wax layer decreased mean root penetration to 31% of the control. The best measure of root penetration in non-flooded conditions was the number of axes penetrating an 80% wax layer. Flooding decreased root penetration of a 60% wax layer to a mean of 26% of the low impedance control. The best measure of root penetration in flooded conditions was the number of axes penetrating a 60% wax layer.     

Waxes enhance Plutella xylostella oviposition in response to sinigrin and cabbage homogenates

Oviposition by the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), on substrates treated with host stimuli (cabbage homogenate or sinigrin) and/or waxes (paraffin or a mixture of 10 single chain n-alkanes) was quantified using continuous observations and endpoint bioassays. Paraffin or an n-alkane mixture applied over cabbage homogenate or sinigrin caused an increase in oviposition compared to that on any single stimulus in choice tests. Sinigrin alone at 10^–5 M to 10^–2 M is an ovipositional stimulant; addition of alkane over sinigrin made all sinigrin concentrations (10^–6 M to 10^–2 M) significantly more stimulatory than controls. Waxes alone do not stimulate oviposition. In choice tests, insect movement between sinigrin/alkane treatment combinations was random, however, once encountered, visit duration was significantly longer on sinigrin with alkane than on sites treated with either stimulus alone. Given the ubiquity of waxes on plant surfaces and the interaction between waxes and host-specific chemical stimuli, waxes should be included when considering factors that significantly influence herbivore host acceptance.     

Diffusion in plant cuticles as affected by temperature and size of organic solutes: similarity and diversity among species

Mobilities of lipophilic organic solutes in cuticular membranes (CM) isolated from mature leaves of Citrus aurantium L., Citrus grandis L., Hedera helix L., IIex aquifolium L., Ilex paraguariensis St.-Hil., Mains domestica Borkh., Prunus armeniaca L., Primus laurocerasus L., Pyrus communis L., Pyrus pyrifolia (Burm. f.) Nakai, Stephanotis florihunda Brongn. and Strophantus gratus Baill. were measured over a temperature range of 15–78°C. In this range, solute mobilities increased up to 1000-fold, which corresponds to temperature coefficients Q₁₀ of 3 (IAA in P. armeniaca) to 14 (cholesterol in H. helix). For most species, Arrhenius graphs showed good linearity up to 40°C, and up to 78°C for some species, while for others activation energies declined with increasing temperature. However, no distinct phase transitions caused by sudden structural changes in the CM were observed. In three species we examined whether heating to 70°C changed solute mobility irreversibly by comparing Arrhenius graphs for two successive experiments with the same CM. The two graphs were very similar for P. laurocerasus, while mobilities in the second graph were somewhat reduced for C. aurantium and greatly increased (at 25 and 35°C) for H. helix. This indicates rearrangements of at least some wax constituents when heated to high temperatures. The activation energies of diffusion (E_D) ranged from 75 to 189 KJ mol^?11 depending on species and solute size. Size selectivity and variability between cuticles decreased with increasing temperature, and this is caused by differences in (E_D). An excellent correlation between the pre-exponential factor of the Arrhenius equation and E_D was observed, which is evidence that organic solutes differing greatly in molecular size (130–349 cm³ mol^?1) and cuticle/water partition coefficient (25–10⁸) use similar diffusion paths in the CM of all 12 plant species tested. Diffusion occurs in regions with identical physicochemical properties and differs only in magnitude.     

Phase behaviour and crystallinity of plant cuticular waxes studied by Fourier transform infrared spectroscopy

The phase behaviour of cuticular waxes from leaves of Hedera helix L. and Juglans regia L. was studied by Fourier transform infrared spectroscopy. For this purpose reconstituted waxes, isolated cuticular membranes, dewaxed polymer matrix membranes and whole leaves were studied in the horizontal attenuated total reflection and transmission modes. Melting curves of cuticular waxes were derived from temperature-dependent changes in the absorption maximum of the symmetric stretching mode of CH₂ groups (ν_s, at approx. 2856–2848 cm⁻¹). With increasing temperature absorption band doublets due to CH₂ scissoring (δ_sciss) and rocking (δ_rock) movements (at approx. 1473–1471 and 730–720 cm⁻¹, respectively) indicative of an orthorhombic arrangement of alkyl chains merged into a single peak. The area ratio of the peaks at approx. 720 and 730 cm⁻¹ was used as a measure for aliphatic crystallinity of plant cuticular waxes at a given temperature. The investigations of reconstituted cuticular waxes and those still embedded in isolated cuticles or in situ on the leaf produced comparable results. The findings are discussed in terms of the properties of the cuticular transport barrier. Received: 21 March 1997 / Accepted: 25 April 1997     

Purity of the sacred lotus, or escape from contamination in biological surfaces

The microrelief of plant surfaces, mainly caused by epicuticular wax crystalloids, serves different purposes and often causes effective water repellency. Furthermore, the adhesion of contaminating particles is reduced. Based on experimental data carried out on microscopically smooth (Fagus sylvatica L., Gnetum gnemon L., Heliconia densiflora Verlot, Magnolia grandiflora L.) and rough water-repellent plants (Brassica oleracea L., Colocasia esculenta (L.) Schott., Mutisia decurrens Cav., Nelumbo nucifera Gaertn.), it is shown here for the first time that the interdependence between surface roughness, reduced particle adhesion and water repellency is the keystone in the self-cleaning mechanism of many biological surfaces. The plants were artificially contaminated with various particles and subsequently subjected to artificial rinsing by sprinkler or fog generator. In the case of water-repellent leaves, the particles were removed completely by water droplets that rolled off the surfaces independent of their chemical nature or size. The leaves of N. nucifera afford an impressive demonstration of this effect, which is, therefore, called the “Lotus-Effect” and which may be of great biological and technological importance. Received: 19 August 1996 / Accepted: 12 November 1996     

An avian equivalent of make-up?

We report that a long-distance migrating shorebird, the red knot, makes a complete switch from commonly occurring monoester preen waxes to a much rarer class of higher-molecular-weight diester waxes at the time of take-off to the high arctic breeding grounds. The cold arctic climate would have required a lowering of wax-viscosity, and thus, a shift in the reverse direction. We propose that a sexually selected need for a brilliant plumage has lead to this conter-intuitive temporary shift from monoesters to diester waxes. The difficulty of application of the diester preen waxes under cold conditions would ensure the reliability of the quality-signalling function of this most probably sexually selected trait.