Immunocompetent Infants as a Human Reservoir for Pneumocystis jirovecii: Rapid Screening by Non-Invasive Sampling and Real-Time PCR at the Mitochondria1 Large Subunit rRNA Gene

ABSTRACT. We tested a real-time PCR assay targeting the Pneumocystis jirovecii mitochondria1 large subunit rRNA gene on 240 archival nasopharyngeal aspirates from non-immunosuppressed infants. The sensitivity of this assay appeared close to that of a conventional nested-PCR assay targeting the same locus. Because of its one-step procedure, and its sensitivity and rapidity, the real-time PCR assay is particularly suitable for screening individuals parasitized by P. jirovecii within large populations.     

Effects of small-scale sedimentary patchiness on the distribution of tubificid and lumbriculid worms in Lake Geneva

SUMMARY. 1. The sediment consists of pillow-like formations (0.7 m wide) separated by trenches, 0.2 m wide and 0.1 m deep, over large areas of Lake Geneva (Switzerland).
2. Biomass and total abundance of tubificid and lumbriculid worms were higher on the pillows than in the trenches. Potamothrix vejdovskyi, P. hammoniensis, P. heuscheri and Tubifex tubifex were more abundant on pillows whereas Peloscolex velutinus and Stylodrilus heringianus were relatively more abundant in the trenches.
3. These differences between worm communities suggested that organic sedimentation was higher on the pillows. Sedimentological analyses confirmed this interpretation.
4. Results of large-scale surveys can be biased if sampling design is not adapted to such small-scale patchiness.     

Orthophosphate Relations of Root: NO-3 Effects on Orthophosphate Influx, Accumulation and Secretion into the Xylem

Lamaze, T., Sentenac, H. and Grignon, C. 1987. Orthophosphaterelations of root: NO^–₃effects on orthophosphate influx,accumulation and secretion into the xylem.—J. exp. Bot.38: 923–934. Orthophosphate (Pi) accumulation by barley (Hordeum vulgareL.) roots was specifically inhibited by NO^–₃ as comparedto Cl^– and SO₄^{2 –}, and Pi secretion into the xylemwas stimulated. The inhibition of Pi accumulation by NO^–₃was also observed in roots of intact photosynthesizing horsebean(Vicia faba L.), rice (Oryza sativa L.) and soybean (Glycinemax L.) plants. NO^–₃ effects on Pi transport by rootswere more thoroughly investigated with corn (Zea mays L.). Theywere due to intracellular NO^–₃. Pi secretion was stillstimulated by NO^–₃ after Pi withdrawal from the absorptionsolution. ³²Pi influx decreased during Pi accumulation, supportingthe hypothesis that this ion allosterically regulated its owntransport system by feedback control. This control was modulatedby other anions: the decrease was more pronounced in the presenceof nitrate. Chronologically, the depressive effect of NO^–₃on ³²Pi influx appeared after the inhibition of Pi accumulation.Furthermore, under conditions where Pi accumulation was notaffected by NO^–₃, ³²Pi influx and Pi secretion into thexylem became insensitive to the presence of nitrate. Our hypothesisis that the stimulative effect of NO^–₃ on Pi secretionand the depressive one on ³²Pi influx are the repercussionsof an increase in the Pi cytosolic concentration due to an NO^–₃-induced decrease in Pi uptake by the vacuoles. Key words: Root, orthophosphate fluxes, orthophosphate accumulation, nitrate, ionic interaction     

Contribution à la cytotaxonomie de l'Amelanchier ovalis Medikus (Rosaceae)

L'espèce Amelanchier ovalis Medikus (Syn. Mespilus amelanchier L.), largement distribuée en Europe, comprend une race diplode (2 n = 34) et une race tétraplode (2 n = 68). Celles-ci diffèrent l'une de l'autre par des caractères quantitatifs (taille des feuilles, longuer des pédicelles, des pétales et des graines). Le nom A. ovalis est typifié ici-même par un specimen (L.H. 646.11) de l'Herbier de Linné qui représents le cytotype diplode. Le cytotype tétraplode est nommé ici: A. ovalis subsp. embergeri Favarger et Stearn. Les caractères cytologiques, la distribution et la nomenclature des deux sous-espèces sont discutés.     

Does the M-Phase Promoting Factor (MPF) Activate a Major Ca2+-and Cyclic Nucleotide-Independent Protein Kinase in Starfish Ocytes?

In starfish, the activity of a major Ca²⁺-and cyclic nuleotide-independent protein kinase has been shown to fluctuate in phase with that of MPF along meiotic and mitotic cell cycle (23, 25). Microinjection of α-naphthylphosphate (α-NP), a potent phosphatase inhibitor, increased considerably (from 15 to 546 picomoles/min/mg protein) the activity of this major cycling kinase in homogenates. Although this result supported the view that kinase phosphorylation might induce its own activation, this hypothesis was eliminated because injection of cytoplasm from hormone-stimulated enucleated oocytes, which contained the fully activated kinase but no MPF, failed to trigger kinase activation in recipient oocytes. In contrast, kinase activation was induced in recipient oocytes injected with either cytoplasm taken from nucleated maturing oocytes, which contained high MPF and kinase activities, or cytoplasm taken later from hormone-stimulated and ATP-γ-S-injected oocytes which contained high MPF but low kinase activites. These results indicate that inhibiting dephosphorylation of some regulatory protein activates the M-phase-specific protein kinase. The possibility that the M-phase or maturation-promoting factor (MPF) might be this regulatory protein is discussed.     

Effect of weather on the reproductive rate of Rock Ptarmigan Lagopus muta in the eastern Pyrenees

Understanding the effects of climate on avian life history traits is essential if we wish to predict the demographic consequences of expected climatic changes. We investigated the influence of weather conditions on the reproductive success of Rock Ptarmigan Lagopus muta in the eastern French Pyrenees, one of the southernmost areas inhabited by the species. Reproductive success was estimated in early August between 1997 and 2006 by counting adults and well-grown chicks with pointing dogs. The number of young per adult varied from 0.08 to 0.72. Using Poisson regression and Akaike's information criterion, we selected the best model explaining the effect of weather (date of snowmelt and, for both laying/incubation and post-hatching periods, mean minimum and maximum temperatures, monthly rainfall and number of days with rain) on the proportion of young in August. Reproductive success was positively associated with early appearance of snow-free ground, and date of snowmelt alone was the model that best explained annual variation in reproductive success. Other models, which included a negative effect of rainfall, particularly after hatching, also had some support. Hence, both pre-laying and post-hatching weather conditions influenced reproductive success of Rock Ptarmigan in the eastern French Pyrenees. On a continental scale, reproductive success of alpine populations of Rock Ptarmigan is consistently lower than that of northern populations. This difference in productivity may be partly correlated with climatic conditions observed along an arctic–alpine gradient, the amount and variation of rainfall being greater in southern alpine areas than elsewhere in the species' range.     

Demonstration by organ culture of a cerebral hormone stimulating the secretion of testicular androgen in the oligochaete annelid,Eisenia foetida f. typica Sav.

Previous culture experiments revealed that, in reproductively active E. foetida, the central nervous sytem (CNS) produces a neurohormone necessary for the secretion of an androgen by testes. The tracing of the origin of this neurohormone has now been done by culturing in vitro ovaries and testes with different ganglia of the nerve cord. In the presence of cerebral ganglia (CG), the percentage of testes transformed into ovotestes was low (3%), while reaching respectively 32% and 17% in the associations with sub-esophageal ganglia (SEG) or ganglia of the male or female genital segments (GS ♂ or ♀). Only the neurohormone produced by CG was able to stimulate secretion of the testicular androgen, the existence of which was proved by previous experiments. The secretion of this androgen was enough to transform 28% of the ovaries into ovotestes. On the other hand, no masculinization of the ovaries was observed in the presence of various ganglia of the ventral nerve cord (SEG, GS ♂ or ♀). It appears, therefore, that the secretion of the testicular androgen is stimulated by the CG.     

Variation of DNA Polymerase Activities in Chick Neural Retina as a Function of Age

The activities of DNA polymerases α, β, and γ and of thymidine kinase were determined in the chick neural retina at different stages of embryonic development (starting at seven days) and after hatching (up to five years). Crude extracts of neural retinae were fractionated by centrifugation on sucrose gradients and the enzymatic activities measured using specific assays. The DNA polymerase a activity decreases greatly between 7 and 11 days of incubation. This decrease parallels the decline in mitotic activity. However, a constant residual activity remains after hatching, even in the oldest animals. DNA polymerase β activity increases slightly between 7 and 14 days of incubation; it then decreases slowly until seven days after hatching and remains constant thereafter. DNA polymerase γ activity is maximal between 7 and 14 days of incubation and then decreases until hatching. The activity of thymidine kinase increases slightly during the embryonic life until hatching and remains almost constant thereafter. The implication of these enzymes in DNA replication and repair processes is discussed.