Pleiotrophin inhibits HIV infection by binding the cell surface-expressed nucleolin

The growth factor pleiotrophin (PTN) has been reported to bind heparan sulfate and nucleolin, two components of the cell surface implicated in the attachment of HIV-1 particles to cells. Here we show that PTN inhibits HIV-1 infection by its capacity to inhibit HIV-1 particle attachment to the surface of permissive cells. The beta-sheet domains of PTN appear to be implicated in this inhibitory effect on the HIV infection, in particular the domain containing amino acids 60-110. PTN binding to the cell surface is mediated by high and low affinity binding sites. Other inhibitors of HIV attachment known to bind specifically surface expressed nucleolin, such as the pseudopeptide HB-19 and the cytokine midkine prevent the binding of PTN to its low affinity-binding site. Confocal immunofluorescence laser microscopy revealed that the cross-linking of surface-bound PTN with a specific antibody results in the clustering of cell surface-expressed nucleolin and the colocalization of both PTN and nucleolin signals. Following its binding to surface-nucleolin, PTN is internalized by a temperature sensitive mechanism, a process which is inhibited by HB-19 and is independent of heparan and chondroitin sulfate proteoglycans. Nevertheless, proteoglycans might play a role in the concentration of PTN on the cell surface for a more efficient interaction with nucleolin. Our results demonstrate for the first time that PTN inhibits HIV infection and suggest that the cell surface-expressed nucleolin is a low affinity receptor for PTN binding to cells and it is also implicated in PTN entry into cells by an active process.     

Le Paléoenvironnement des chasseursde Terra Amata (Nice,Alpes-Maritimes) au Pléistocène moyen. La flore et la faune de grands mammifères

The «living floors of the Acheulean huntersof Terra Amata are situated in their stratigraphical framework; they are included in a beach ridge and in a dune ascribed to the Mindelian glaciation and followed by a substantial paleosol ascribed to the Mindel-Riss interglacial. Palynological studies made in the deposits of the Middle Pleistocene show a rather great rate of forest-trees. The relative importance of trees growing in cool and wet areas and of thermophilous or typically mediterranean species, in every layers, allows to indicate a succession of climatic oscillations inside of a long and rather mild period. Among large mammals, the absence of any archaic form and of any recently appeared form, does not make it possible neither to confirm nor to exclude the hypothesis of a «Mindelian age for this fauna. The faunistic assemblage likewise corresponds to a temperate climate and a forest environment.     

The gene for the type 1 tumor necrosis factor receptor (TNF-R1) is localized on band 12p13

Summary The gene coding for the type I (p55) tumor necrosis factor receptor (TNF-R1) has been localized on human chromosome 12, band 12p13.2, by in situ hybridisation using a biotinylated genomic probe.     

The gene for the type II (p75) tumor necrosis factor receptor (TNF-RII) is localized on band 1p36.2–p36.3

Summary The gene encoding the type II (p75) tumor necrosis factor receptor (TNF-RII) has been localized on human chromosome 1, band 1p36.2 by nonradioactive in situ hybridization. The gene encoding the type I (p55) TNF-R, which is structurally homologous to the type II (p75) TNF-R, has been previously localized on chromosome 12 band 12p13. Thus, despite their probable common ancestry, the genes for the two TNF-Rs are localized on different chromosomes.     

Facteurs de limitation des populations d'Aphis fabae dans l'ouest de la France

Résumé Dans l'ensemble d'études consacrées aux épizooties àEntomophthoraceae surAphis fabae (Scopoli) en Bretagne, ce travail présente les résultats obtenus de 1972 à 1974 à l'aide d'échantillons importants (100 à 300 plantes). Ces résultats concernent principalementNeozygites fresenii (Now.)Remaudière & Keller. En 1972, les conditions climatiques sont tamponnées et constamment favorables aux mycoses. Le nombre d'aphides sains et d'aphides mycosés suit une évolution exponentielle particulièrement régulière; l'effet (évolution du pourcentage de mycosés) n'en est pas moins très brusque. L'arrivée des mycoses dans la parcelle a lieu en même temps que celle des pucerons, ce qui plaide en faveur d'une contamination exogène à laquelle prendraient part les ailés de différentes espèces. Le début du développement de la maladie n'est pas homogène dans l'espace. Les tout premiers mycosés apparaissent dans n'importe quelle colonie, mais très vite on constate que ce sont les colonies les plus grosses qui comportent le plus de mycosés. Cependant, cette relation, qui reste valable pendant la suite de l'épizootie, est très lache. A un moment donné de son déroulement, quelle que soit la taille des colonies concernées, il y a une large gamme de variabilité dans leur taux de parasitisme. Les formes adultes sont systématiquement plus mycosées que les formes larvaires, mais la différence s'amenuise jusqu'à s'annuler à la fin de l'épizootie. En juillet, selon les années, les pucerons mycosés peuvent ou non former des spores durables; en 1972, seulement 2,6 % d'entre eux en forment, mais la répartition de ces individus dans le champ est très homogène.

---

Summary This 4th study on epizootics that occur in the populations of the black bean aphid in Brittany, deals with data obtained between 1972 and 1974 using large samples (100 to 300 plants). The results concern mainlyNeozygites fresenii (Nowak) Remaudière & Keller. In 1972, the weather was not very changeable and always favourable for the fungi (table 1). The number of healthy aphids as well as the number of diseased ones, followed a remarkably regular exponential curve. As a result, the variation of the percentage of dead aphids was very sudden (fig. 1, fig. 2). The disease appeared in the fields at the same time as the aphids themselves; so it is possible to think that several species of winged aphids play a part in the introduction of the 1st inoculum into the field (table 2). At its beginning, the development of the disease was not homogeneous in space (table 4). The foremost diseased aphids could be found in any colony whatever its size, but before long it was found that the biggest colonies contained the greatest number of diseased aphids (table 3). Though this relation remained during the continuation of the epizooty, it was a loose one (table 5). At a given time, within colonies of a given size, the percentage of dead aphids was very variable (fig. 3). The adults (winged and apterae)_were systematically more diseased than the nymphs, but the difference became smaller as time went on, and it finally disappeared at the end of the epizooty (table 6). Some years in July, the diseased aphids could form resting spores; in 1972, 2.6% of them formed resting spores, and the spatial dispersion of these individuals was very regular (table 7).

---

---

Les 3 premiers mémoires de cette étude ont été publiés dansEntomophaga respectivement parRobert, Rabasse & Scheltes (18, 1973, 61–75) parRabasse & Robert (20, 1975, 49–63) et parDedryver (23, 1978, 137–151).     

Human C3 deficiency associated with impairments in dendritic cell differentiation, memory B cells, and regulatory T cells

Primary C3 deficiency, a rare autosomal inherited disease (OMIM 120700), was identified in a 2-year-old male suffering from recurrent pyogenic infections from early infancy with undetectable total complement hemolytic activity (CH50) and C3 values. The nonconsanguineous parents and the two patients' two siblings had 50% normal serum C3 concentration. The molecular abnormality associated a paternal allele coding C3 with the missense mutation p.Ser(550)Pro and an apparently null maternal allele, with production of a defective protein that could no longer be secreted. Vaccination of the child did not induce a long-term Ab response. Accordingly, switched memory IgD(-)CD27(+) B cells were barely detected, amounting to only 2.3% of peripheral blood CD19(+) cells. Cells were significantly defective in stimulating alloreactive responses. The in vitro development of immature dendritic cells and their maturation capacity were greatly impaired, with decreased CD1a expression and IL-12p70 secretion ability. These cells were unable to induce autologous B cell proliferation and Ig secretion in the presence of CD40L and C3. Finally, the regulatory T cell development ability of CD4(+) T cells after CD3 and CD46 activation in the presence of IL-2 was significantly impaired. Thus, the association of important functional defects of dendritic cells, acquisition of B cell memory, and regulatory T cells with human C3 deficiency strongly supports a major role for C3 in bridging innate and adaptive immunity in humans.     

Using macro-arrays to study routes of infection of Helicobacter pylori in three families

Background

Analysis of the evolutionary dynamics of Helicobacter pylori allowed tracing the spread of infection through populations on different continents but transmission pathways between individual humans have not been clearly described.

Materials and Methods

To investigate person-to-person transmission, we studied three families each including one child with persistence of symptoms after antibiotic treatment. Ten isolates from the antrum and corpus of stomach of each family member were analyzed both by sequencing of two housekeeping genes and macroarray tests.

Results

A total of 134 (8.4%) out of the 1590 coding sequences (CDSs) tested, including cag PAI and insertion sequences, were present in some but not all isolates (and are therefore defined as variable CDSs). Most of the variable CDSs encoded proteins of unknown function (76/134) or were selfish DNA including that encoding restriction/modification enzymes (13/134). Isolates colonizing the stomach of one individual can vary by point mutations, as seen in hspA, or by the gain or loss of one to five CDSs. They were considered as (genetic) variants. The phylogenetic clustering of gene profiles obtained on macro-arrays allowed identifying the different strains infecting families. Two to five strains circulated within a family. Identical strains were present in at least two members of all three families supporting the accepted model of intrafamilial transmission. Surprisingly, the mother was not implicated in the transmission of H. pylori in the two French families. Sibling-to-sibling transmission and acquisition of H. pylori from outside the family appeared to be probable in the transmission pathways.

Conclusion

Macroarray analysis based on previously selected CDSs gives a comprehensive view of the genome diversity of a pathogen. This approach combined with information on the origin of the hspA and glmM alleles revealed that Helicobacter pylori infection may be acquired by more diverse routes than previously expected.     

Delay in Diagnosis of Testicular Cancer; A Need for Awareness Programs

Background Aim

To gain insight into patient and doctor delay in testicular cancer (TC) and factors associated with delay.

Materials and Methods

Sixty of the 66 eligible men; median age 26 (range 17–45) years, diagnosed with TC at the University Medical Center Groningen completed a questionnaire on patients’ delay: interval from symptom onset to first consultation with a general practitioner (GP) and doctors’ delay: interval between GP and specialist visit.

Results

Median patient reported delay was 30 (range 1–365) days. Patient delay and TC tumor stage were associated (p = .01). Lower educated men and men embarrassed about their scrotal change reported longer patient delay (r = -.25, r = .79 respectively). Age, marital status, TC awareness, warning signals, nor perceived limitations were associated with patient delay. Median patient reported time from GP to specialist (doctors’ delay) was 7 (range 0–240) days. Referral time and disease stage were associated (p = .04). Six patients never reported a scrotal change. Of the 54 patients reporting a testicular change, 29 (54%) patients were initially ‘misdiagnosed’, leading to a median doctors’ delay of 14 (1–240) days, which was longer (p< .001) than in the 25 (46%) patients whose GP suspected TC (median doctors’ delay 1(0–7 days).

Conclusions

High variation in patients’ and doctors’ delay was found. Most important risk variables for longer patient delay were embarrassment and lower education. Most important risk variable in GP’s was ‘misdiagnosis’. TC awareness programs for men and physicians are required to decrease delay in the diagnosis of TC and improve disease free survival.     

Expression in Escherichia coli and purification of human recombinant connexin-43, a four-pass transmembrane protein

We have recently shown, using a well-defined in vitro model, that connexin 43 (Cx43) is directly involved in human cytotrophoblastic cell fusion into a multinucleated syncytiotrophoblast. Cx43 appears to interact with partner proteins within a fusogenic complex, in a multi factorial and dynamic process. This fusogenic complex remains to be characterized and constituent proteins need to be identified. In order to identify proteins interacting with the entire Cx43 molecule (extracellular, transmembrane and intracellular domains), we produced and purified full-length recombinant Cx43 fused to glutathione S-transferase (GST-Cx43) and used it as "bait" in GST pull-down experiments. Cx43 cDNA was first cloned into the pDEST15 vector in order to construct a GST-fusion protein, using the Gateway system. The fusion protein GST-Cx43 was then expressed in Escherichia coli strain BL21-AI? and purified by glutathione-affinity chromatography. The purified fusion protein exhibited the expected size of 70 kDa on SDS-PAGE, western blot and GST activity. A GST pull-down assay was used to show the capacity of the full-length recombinant protein to interact with known partners. Our results suggest that this method has the capacity to produce sufficient full-length recombinant protein for investigations aimed at identifying Cx43 partner proteins.