Impact of <Emphasis Type="Italic">Quillaja saponaria</Emphasis> saponins on grapevine ecosystem organisms

The control of grapevine pathogens is a rising concern in Vitis vinifera culture. The current international trend is toward banning chemicals that are highly toxic to the environment and human workers, and adopting tighter regulations. We evaluated the impact of saponins on three kinds of organisms found in grapevine culture. The ectoparasitic nematode Xiphinema index, the parasitic fungus Botrytis cinerea and various yeast strains representative of the must fermentation population were incubated on synthetic media supplemented with variable concentrations of Quillaja saponaria saponins. Saponins induced reduction in the growth of B. cinerea and showed nematicide effects on X. index. The control of X. index and Botrytis cinerea is discussed in the context of the potential use of these chemicals as environmentally-friendly grapevine treatments. With Saccharomyces cerevisiae and other yeasts, saponins showed higher toxicity against S. cerevisiae strains isolated from wine or palm wine whereas laboratory strains or strains isolated from oak exhibited better resistance. This indicates that Q. saponaria saponins effects against yeast microflora should be assessed in the field before they can be considered an environmentally-safe new molecule against B. cinerea and X. index.     

Assessment of Metabolomic and Proteomic Biomarkers in Detection and Prognosis of Progression of Renal Function in Chronic Kidney Disease

Chronic kidney disease (CKD) is part of a number of systemic and renal diseases and may reach epidemic proportions over the next decade. Efforts have been made to improve diagnosis and management of CKD. We hypothesised that combining metabolomic and proteomic approaches could generate a more systemic and complete view of the disease mechanisms. To test this approach, we examined samples from a cohort of 49 patients representing different stages of CKD. Urine samples were analysed for proteomic changes using capillary electrophoresis-mass spectrometry and urine and plasma samples for metabolomic changes using different mass spectrometry-based techniques. The training set included 20 CKD patients selected according to their estimated glomerular filtration rate (eGFR) at mild (59.9±16.5 mL/min/1.73 m²; n = 10) or advanced (8.9±4.5 mL/min/1.73 m²; n = 10) CKD and the remaining 29 patients left for the test set. We identified a panel of 76 statistically significant metabolites and peptides that correlated with CKD in the training set. We combined these biomarkers in different classifiers and then performed correlation analyses with eGFR at baseline and follow-up after 2.8±0.8 years in the test set. A solely plasma metabolite biomarker-based classifier significantly correlated with the loss of kidney function in the test set at baseline and follow-up (ρ = −0.8031; p<0.0001 and ρ = −0.6009; p = 0.0019, respectively). Similarly, a urinary metabolite biomarker-based classifier did reveal significant association to kidney function (ρ = −0.6557; p = 0.0001 and ρ = −0.6574; p = 0.0005). A classifier utilising 46 identified urinary peptide biomarkers performed statistically equivalent to the urinary and plasma metabolite classifier (ρ = −0.7752; p<0.0001 and ρ = −0.8400; p<0.0001). The combination of both urinary proteomic and urinary and plasma metabolic biomarkers did not improve the correlation with eGFR. In conclusion, we found excellent association of plasma and urinary metabolites and urinary peptides with kidney function, and disease progression, but no added value in combining the different biomarkers data.     

Bestandsentwicklung, Durchzug und Herkunft des KormoransPhalacrocorax carbo an einem Winterrastplatz auf Helgoland

Zusammenfassung Die Rastbestände des Kormorans auf Helgoland sind seit den 1970er Jahren stark angestiegen. Die Summe der Pentadenmaxima nahm von 1984 bis 1989 um jährlich 47 % zu. Obwohl sich die Beobachtungsintensität für Rastbestände seit 1991 stark verringerte, stieg die Maximalzahl bis 1996 auf 661 Kormorane. Bis Ende der siebziger Jahre wurden die Maxima in den Zugzeiten erreicht, seit etwa 1980 wird Helgoland dagegen zunehmend als Winterrastplatz genutzt. Die Rastbestände stiegen vor allem im September/Oktober an, erreichten Maxima von Dezember bis März und sanken von Ende März bis Mai. Der Winterbestand baute sich von 1979 bis 1996 im Herbst zunehmend schneller auf (um mehr als 100 Tage) und nahm im Frühjahr zeitiger ab (um 43 Tage). Ziehende Kormorane wurden hingegen vor allem im März/April (Median: 12. April) und von Ende Juli bis Oktober (Median: 16. September) beobachtet. Im Frühjahr ziehen Kormorane überwiegend in ost-/nordöstliche, im Herbst in west/südwestliche Richtung. 67 % flogen in Trupps mit 11–40 Individuen (Median: 27). Zugbeobachtungen fielen mit 69 % der Individuen in die Zeit bis 12 Uhr (Median: 10:05 Uhr). Von 6 Ringfunden stammen je 1 aus den Niederlanden und Norwegen sowie 4 aus Dänemark. Von 36 Totfunden auf Helgoland seit 1984 gehörten 19 nach Maßen sicher zur UnterartPhalacrocorax c. carbo, nur 9 zuP. c. sinensis. Das Gros der auf Helgoland überwinternden Kormorane stellt demnach vermutlichP. c. carbo. Vögel dieser Subspezies überwintern zudem weniger weit im Süden alssinensis und bevorzugen marine Habitate und felsige Küsten. Ein Wintermaximum vonP. c. sinensis ist daher zwar für Überwinterungsgebiete in Mittel- und Südeuropa bekannt, nicht aber aus dem Bereich der übrigen Nordsee und dem Wattenmeer. Die Brutbestände vonsinensis haben in Dänemark und Südschweden seit 1980/81 stark zugenommen, weniger diejenigen voncarbo in Norwegen. Parallel zur Zunahme der Winterbestände vonsinensis im Skagerrak und Kattegat, einem bisher typischen Überwinterungsraum voncarbo, kam es 1983–1985 zu mindestens 9 Ringfunden norwegischer Vögel in Mittel- und Südeuropa sowie 1976–1989 zu 6 Ringfunden in Nordost-Deutschland. Möglicherweise trug eine zunehmende Konkurrenz im Skagerrak und Kattegat zu dem Aufbau und der starken Zunahme der Winterbestände auf Helgoland bei. Parallelen einer Konkurrenz zwischencarbo undsinensis sind in Westfrankreich zu finden.

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Numbers, migration and origin of CormorantsPhalacrocorax carbo at a wintering site on the island of Helgoland (German Bight, North Sea)

The numbers of Cormorants resting on the island of Helgoland (54° 11 N, 7° 53 E) have increased considerably since the 1970s. Annual totals of the maxima per five-day period rose by 47 % per year from 1984 to 1989. Although the observation effort decreased, annual maxima further increased to 661 birds in 1996 (Fig. 1). Up to the late seventies, annual maxima of resting birds were occurred during the migration periods, whereas since about 1980 Helgoland is increasingly used as a wintering site. Resting numbers grew mainly in September/October, reached their maxima from December to March and fell again from the end of March to May (Fig. 2). Today arrival takes place more than 100 days earlier and departure 43 days earlier than in 1979 (Fig. 3). Migrating Cormorants were mainly observed in March and April (median: 12. April) and from the end of July to October (median: 16. September, Fig. 4). They prefer eastern and north-eastern directions in spring, and western and southwestern directions in autumn (Fig. 5). 67 % of the individuals were observed to migrate in flocks of 11 to 40 individuals (median 27, Fig. 6), and 69 % of migrating individuals were counted before midday (median: 10:05 hours, Fig. 7). Six ringed birds were found or observed at Helgoland. They were ringed in The Netherlands (1), Denmark (4) and Norway (1). According to their body measurements, 19 out of a total of 36 Cormorants found dead at Helgoland are assumed to belong to the subspeciescarbo, whereas only 9 are presumablyP. c. sinensis. Hence, we believe that most birds wintering at Helgoland belong toP. c. carbo. This subspecies winters less far south thansinensis and prefers marine habitats and rocky shores. Winter maxima ofsinensis are only known from wintering sites further south but not from the North Sea and the Wadden Sea, where maxima occur during spring and autumn migration. Breeding numbers ofP. c. sinensis have increased considerably in Denmark and south Sweden since 1980/81, whereas thoseP. c. carbo numbers have increased at a lesser rate. Coinciding with the increase of winteringsinensis in the Skagerrak and Kattegat area (a formerly typical wintering site ofcarbo), there were at least 9 recoveries of birds ringed in Norway in central and south Europe from 1983–85 and 6 in northeastern Germany from 1976–89. Probably, the establishment and growth of the winter population at Helgoland is a result of increasing competition in the Skagerrak and Kattegat. Similar developments betweencarbo andsinensis have been observed in northwest France.

     

Flooding, gas exchange and hydraulic root conductivity of highbush blueberry

Highbush blueberry plants ( Vaccinium corymbosum L. cv. Bluecrop) growing in containers were flooded in the laboratory for various durations to determine the effect of flooding on carbon assimilation, photosynthetic response to varying CO₂ and O₂ concentrations and apparent quantum yield as measured in an open flow gas analysis system. Hydraulic conductivity of the root was also measured using a pressure chamber. Root conductivity was lower and the effect of increasing CO₂ levels on carbon assimilation less for flooded than unflooded plants after short-(i-2 days), intermediate-(10–14 days) and long-term (35–40 days) flooding. A reduction in O₂ levels surrounding the leaves from 21 to 2% for unflooded plants increased carbon assimilation by 33% and carboxylation efficiency from 0.012 to 0.021 mol CO₂ fixed (mol CO₂)⁻¹. Carboxylation efficiency of flooded plants, however, was unaffected by a decrease in percentage O₂, averaging 0.005 mol CO₂ fixed (mol CO₂)⁻¹. Apparent quantum yield decreased from 2.2 × 10⁻¹ mol of CO₂ fixed (mol light)⁻¹ for unflooded plants to 2.0 × 10⁻³ and 9.0 × 10⁻⁴ for intermediate- and long-term flooding durations, respectively. Shortterm flooding reduced carbon assimilation via a decrease in stomatal conductance, while longer flooding durations also decreased the carboxylation efficiency of the leaf.     

Short-Term Flooding Effects on Gas Exchange and Quantum Yield of Rabbiteye Blueberry (Vaccinium ashei Reade)

Roots of 1.5-year-old `Woodard' rabbiteye blueberry plants (Vaccinium ashei Reade) were flooded in containers or maintained at container capacity over a 5-day period. Carbon assimilation, and stomatal and residual conductances were monitored on one fully expanded shoot/plant using an open flow gas analysis system. Quantum yield was calculated from light response curves. Carbon assimilation and quantum yield of flooded plants decreased to 64 and 41% of control values, respectively, after 1 day of flooding and continued decreasing to 38 and 27% after 4 days. Stomatal and residual conductances to CO₂ also decreased after 1 day of flooding compared with those of unflooded plants with residual conductance severely limiting carbon assimilation after 4 days of flooding. Stomatal opening occurred in 75 to 90 minutes and rate of opening was unaffected by flooding.     

Net photosynthetic rate of sour cherry (Prunus cerasus L. ‘Montmorency’) during the growing season with particular reference to fruiting

Diurnal and seasonal net photosynthetic rates (Pn) of sour cherry were determined. Leaf Pn was not significantly affected by shoot excision. Under constant environmental conditions (PFD, 1200 mol m^-2 s^-1; temp. 25; relative humidity, 80–90%) there was no significant diurnal fluctuation in Pn for individual leaves. However, there was a pronounced fluctuation in Pn for whole trees measured under constant temperature but natural variation in sunlight from sunrise to sunset. Maximum Pn occurred before solar noon, remained constant for 1–2 hr, then declined. Photosynthetic rate of recently expanded leaves fluctuated through out the season but, in general, was greatest in the spring as leaves expanded, reached a peak, remained stable for several weeks, then gradually declined. The Pn of leaves on terminal shoots was not significantly different from the Pn of leaves on spurs of the same physiological age. The presence of fruit did not have a consistent effect on the Pn of sour cherry leaves.Michigan Agricultural Experiment Station Journal Article No. 10739.     

Structure and dynamics of phosphate linkages and sugars in an abasic hexaloop RNA hairpin

Hairpins containing hexaloops are well represented among the diverse conformations adopted by the RNA molecules. To investigate the intrinsic properties of a backbone submitted to a hexaloop fold, we present here a molecular dynamics study of an abasic hexaloop closed by an A-form 6 basepair stem. The analysis of the 23 ns trajectory made in explicit solvent shows that both the sugars and the torsion angles in the loop undergo numerous conformational transitions. The south sugars, although not in a majority, are the major actors of the loop stretching. The five torsion angles, epsilon, zeta, alpha, beta, and gamma, are unequally variable, and only zeta and alpha exhibit trimodal distributions. The analysis of the phosphate linkages in terms of epsilonzeta'-alpha'-beta'-gamma-combinations allows us to define five conformational families, each one composed of one major substate in equilibrium with several less populated ones. The transitions between the substates within a family follow specific pathways involving the angles epsilon, zeta, and alpha. Thus, this work reveals that the backbone conformational space is both reduced and ordered even in a hexaloop devoid of bases.     

The p76 and p100 truncated forms of the Rb protein exert antagonistic roles on cell death regulation in human cell lines

Several caspase-cleaved forms of the retinoblastoma protein have been described. Here, we compared the effect of full-length Rb versus the truncated p76^Rb and p100^Rb proteins on cell death regulation in five human cell lines. Interestingly, we observed that p76^Rb triggers cell death in all tested cell lines and that p100^Rb protects two cell lines against etoposide or TNF-α-induced cell death, whereas full-length Rb has no apoptotic effect. These results show that truncated forms of Rb can have specific activities in the regulation of cell death. They also suggest that caspase cleavage of Rb should not be simply assimilated to a degradation process. Finally, we show that cell death induced by p76^Rb is Bax-dependent and is diminished by Bcl-2 overexpression or by caspase inhibition and that p100^Rb could inhibit cell death by decreasing both p53 stability and caspase activity.     

Lifespan extension by preserving proliferative homeostasis in Drosophila

Regenerative processes are critical to maintain tissue homeostasis in high-turnover tissues. At the same time, proliferation of stem and progenitor cells has to be carefully controlled to prevent hyper-proliferative diseases. Mechanisms that ensure this balance, thus promoting proliferative homeostasis, are expected to be critical for longevity in metazoans. The intestinal epithelium of Drosophila provides an accessible model in which to test this prediction. In aging flies, the intestinal epithelium degenerates due to over-proliferation of intestinal stem cells (ISCs) and mis-differentiation of ISC daughter cells, resulting in intestinal dysplasia. Here we show that conditions that impair tissue renewal lead to lifespan shortening, whereas genetic manipulations that improve proliferative homeostasis extend lifespan. These include reduced Insulin/IGF or Jun-N-terminal Kinase (JNK) signaling activities, as well as over-expression of stress-protective genes in somatic stem cell lineages. Interestingly, proliferative activity in aging intestinal epithelia correlates with longevity over a range of genotypes, with maximal lifespan when intestinal proliferation is reduced but not completely inhibited. Our results highlight the importance of the balance between regenerative processes and strategies to prevent hyperproliferative disorders and demonstrate that promoting proliferative homeostasis in aging metazoans is a viable strategy to extend lifespan.