Iridoid glucosides in fouquieriaceae

From three Fouquieria sp. 12 iridoid glucosides were isolated and identified. Eight of these were structurally related to galioside (monotropein methylester), while four were hydroxy substitution products of deoxyloganin. In three cases the glucoside occurred together with the corresponding 10-O-acetate.     

Os penis of the rat. V. The distal cartilage process

The morphogenesis and morphology of the distally positioned cartilage of the os penis, the processus cartilagineus, are described in rats aged from 1 to 100 days. Based on observations of metachromacy of the process stained with toluidine blue it was found that a processus cartilagineus only exists in the period between 35 and 50 days of age. Before 35 days, the structure consists of connective tissue proper, and after 50 days the cartilage starts to calcify partially. The present paper also initiates studies of experimentally caused alterations of the normal development of the processus cartilagineus by subjecting 35-day-old rats to castration, with subsequent sacrifice at 100 days. Castration at that age causes a complete interruption of normal development of the processus cartilagineus as the structure in 100-day-old castrated rats has distinct morphological characteristics in common with those of 35-day-old normal rats. The present paper, thus, confirms that normal development of the processus cartilagineus seems to be male-hormone-dependent.     

DNA-damaging properties and cytotoxicity in human fibroblasts of tetrachlorohydroquinone, a pentachlorophenol metabolite

The DNA-damaging potential of pentachlorophenol (PCP) and its metabolite tetrachlorohydroquinone (TCH) was investigated. TCH was found to bind covalently to calf-thymus DNA and to cause single-strand breaks in PM2 DNA. No DNA-damaging effects were observed for PCP. Exposure of human fibroblasts to PCP and TCH showed that TCH is more toxic, when colony-forming ability after exposure to the agent is used as a measure of toxicity. In the evaluation of the mutagenic and carcinogenic potential of PCP the metabolite TCH should be taken into consideration.     

Demonstration of a beta-casomorphin immunoreactive material in the plasma of newborn calves after milk intake

Blood was collected from newborn calves before and after their first milk intake after birth; extracts of plasma were assayed by radioimmunoassay for the presence of beta-casomorphin-7 immunoreactive materials. No beta-casomorphin immunoreactivity was found in samples collected before milk ingestion; however, in samples collected after milk ingestion a beta-casomorphin-7 immunoreactive material was detected. Chromatographic characterization showed that this material was not identical with beta-casomorphin-7 but might rather represent a precursor thereof. The material proved resistant to enzymatic attack during a 30-min incubation period at 37 degrees C in the plasma of newborn calves, whereas beta-casomorphin-7 was degraded under these conditions. A physiological significance of beta-casomorphin-7 eventually cleaved from such a precursor material at any site in the newborn mammal is suggested.     

Ion balance in tomato cultivars differing in salt tolerance. I. Sodium and potassium accumulation and fluxes under moderate salinity

The magnitude of sodium and potassium fluxes in Lycopersicon escutentum cuhivars Ace and Edkawi (Edkawi is considered more sait-tolerant I was evaluated in planls grown for 10 days in aerated Hoagland solution with the addition of 25 or 100 mM NaCl. Ion accumulatiun in different plant pans, ion concentration in xylem exudate. transpiration and membrane leakiness were measured. Both cultivars responded very similarly to these levels of salinity in terms of growth. No conspicuous differences in membrane leakiness were observed. Net uprake rates were calculated from ion contents data. Potassium uptake rates were lower in salinized planls than in controls, especially in cv. Aee. Potassium/sodium selectivity ratios were much higher in Edkawi than in Ace. and higher in shoot uptake rates than in xy lem exudate. This indicates that Edakw i has a higher capacity to retain potassium under salinity, a character which could contribute to its salt-tolerance.     

Human appropriation of net primary production as driver of change in landscape-scale vertebrate richness

Aim

Land use is the most pervasive driver of biodiversity loss. Predicting its impact on species richness (SR) is often based on indicators of habitat loss. However, the degradation of habitats, especially through land-use intensification, also affects species. Here, we evaluate whether an integrative metric of land-use intensity, the human appropriation of net primary production, is correlated with the decline of SR in used landscapes across the globe.

Location

Global.

Time period

Present.

Major taxa studied

Birds, mammals and amphibians.

Methods

Based on species range maps (spatial resolution: 20 km × 20 km) and an area-of-habitat approach, we calibrated a “species–energy model” by correlating the SR of three groups of vertebrates with net primary production and biogeographical covariables in “wilderness” areas (i.e., those where available energy is assumed to be still at pristine levels). We used this model to project the difference between pristine SR and the SR corresponding to the energy remaining in used landscapes (i.e., SR loss expected owing to human energy extraction outside wilderness areas). We validated the projected species loss by comparison with the realized and impending loss reconstructed from habitat conversion and documented by national Red Lists.

Results

Species–energy models largely explained landscape-scale variation of mapped SR in wilderness areas (adjusted R²-values: 0.79–0.93). Model-based projections of SR loss were lower, on average, than reconstructed and documented ones, but the spatial patterns were correlated significantly, with stronger correlation in mammals (Pearson's r = 0.68) than in amphibians (r = 0.60) and birds (r = 0.57).

Main conclusions

Our results suggest that the human appropriation of net primary production is a useful indicator of heterotrophic species loss in used landscapes, hence we recommend its inclusion in models based on species–area relationships to improve predictions of land-use-driven biodiversity loss.     

Induced responses in three tropical dry forest plant species – direct and indirect effects on herbivory

Induced changes in plant quality are hypothesized to reduce herbivore numbers and subsequent damage to the plant. The resultant decrease in herbivory may be due to direct negative impacts on herbivores, through the reduction in foliage quality as food, or due to indirect effects of plant-induced traits interacting with the third trophic level, increasing predation and parasitism rates on herbivores. The relative importance of induced responses as direct and/or indirect defenses has not been evaluated in natural systems. Moreover, few studies have evaluated the influence of early-season damage on late-season herbivory in natural systems, particularly in the tropics. The presence of induced responses and subsequent impact on folivory as a consequence of early-season damage were evaluated in three plant species ( Croton pseudoniveus , Bursera instabilis and Piper stipulaceum ) in a tropical dry forest in Mexico. A two-factorial experiment was applied to determine if induced responses influenced subsequent herbivory directly, by reducing foliage quality, or indirectly, through their interaction with parasitoids and predatory arthropods. Plants from all three species with reduced early-season damage had higher herbivory rates through the rest of the growing season, compared to plants that were damaged during leaf expansion. Chemical analyses showed that early-season damage induced the production of total phenolics and condensed tannins for C. pseudoniveus and B. instabilis , respectively. The mechanism by which these compounds affected subsequent herbivory was most likely by directly reducing foliage quality as food for herbivores, given that predatory arthropods and parasitoids had no effects on herbivory in this study. I conclude that early-season damage in these three species influenced later-season herbivory through the induction of plant responses that may act to reduce plant quality as food for herbivores.     

Vegetation changes of a Danish mire 1957–1981

A Danish mire influenced by culture until ca. 100 years ago and since then with incipient growth of Betula pubescens , was analyzed in 1957 and 1981 with regard to height of the Betula trees and cover percentage of plant species in the field layer. In 1957, every m2 along a 110 m transect was examined; in 1981 only 56 m2 representatively selected from the transect were examined. Betula showed considerable changes with a net intake of 10 trees (23%) and a net loss of 23 trees (52%), i.e. a net loss of 13 trees (30%). The mean height of the trees has, however, increased by 80 cm and the sum of the height of the trees per m2 by 29 cm. An increased total cover was found for Em–petrum nigrum, Molinia coerulea , and Erica tetralix , and a decreased total cover for Calluna, Sphagnum magellanicum, S. nemoreum, S. rubellum, Hypnum cupressi–forme, Pleurozium schreberi , and Aulacomnium palustre. An almost unchanged total cover was found for Eriophorum vaginatum, E. angustifolium, Sphagnum recurvum, Andromeda polifolia, Drosera rotundifolia , and Oxycoccus palustris. On the basis of quantitative changes in the individual plots, a specific index of change is calculated, decreasing in the order Empetrum > Sphagnum magellanicum > S. recurvum = Molinia > Calluna > Hypnum cupressiforme > Pleurozium schreberi> Oxycoccus palustre> Sphagnum nemoreum = S. rubellum = Eriophorum vaginatum = E. angustifolium > Aulacomnium palustre > Erica> Drosera > Andromeda. Analyses from 1981 demonstrate that usually the light conditions and/or the water content and rarely the bulk density of the soil is correlated with the change in cover of the individual species. For some species it is also shown that the change is correlated with the strongly increased cover of Empetrum in particular. The changes are finally illustrated by showing the position of the species along ecological gradients in 1981.     

Phosphorylation of glycogen synthase I from human polymorphonuclear leukocytes

Summary Glycogen synthase I from human polymorphonuclear leukocytes was phosphorylated with cAMP dependent protein kinase, synthase kinase or phosvitin kinase prepared from these cells. Limited tryptic hydrolysis released four phosphopeptides (t-A, t-B, t-C, t-D). Subsequent α-chymotryptic hydrolysis of the trypsin resistant core released three phosphopeptides. (c-A, c-B, c-C). The kinetic changes of glycogen synthase were compared with the phosphorylation of the peptides. Equivalent kinetic changes (K_c=0.2–0.3 mM Glc-6-P) were obtained when 1 P_i/subunit was introduced by cAMP dependent protein kinase, 0.5 P_i/subunit by synthase kinase and 0.8 P_i/subunit by both kinases. Initially, cAMP dependent protein kinase phosphorylated peptides c-A and t-C in parallel and somewhat later also t-B, whereas synthase kinase initially phosphorylated only c-A. The ultimate effect of the two kinases on c-A was additive. It was concluded that the initial kinetic changes were dependent on phosphorylation of c-A, which contained two sites, one for each kinase. The same kinetic changes were induced by phosphorylation on each of the sites. In the subsequent phosphorylation the kinases, separately or together, phosphorylated peptide c-C indicating one non-specific phosphorylatable site in this peptide. The cAMP dependent protein kinase alone phosphorylated t-C maximally, whereas both kinases were required for an equal phosphorylation of t-A and t-B. It is suggested that the cAMP dependent protein kinase phosphorylated t-A and t-C, whereas the data did not allow a similar suggestion for t-B. The kinetic changes occurring during the later stages of phosphorylation were an increase in K_c for Glc. 6-P to 4–5 mM at 1.85 P_i/subunit and to 20 mM at 3.3 P_i/subunit, but the changes could not be assigned to phosphorylation of any specific peptide. Phosphorylation of the peptides t-D and c-B were insignificant, but c-B may be phosphorylated under other experimental conditions (25). The phosvitin kinase phosphorylated glycogen synthase extremely slowly to an extent of 0.8 P_i/subunit, mainly in peptide c-C. Glycogen synthase would appear without physiological importance as substrate for this kinase. Phosphorylase kinase from rabbit skeletal muscle incorporated 0.7 P_i/subunit, mainly in peptide c-A causing a decrease in RI to 0.3, which upon further incubation remained constant. The rate of decrease in RI to 0.5 was unaffected by several synthase modifiers, including Glc-6-P, but was inhibited by ADP and P_i. The rate of phosphorylation by cAMP dependent protein kinase and synthase kinase was diversely affected in different buffers, however, without affecting the ultimate phosphorylation pattern.