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See detailAn endogenous gibbon ape leukemia virus (GALV) identified in a rodent (Melomys sp.) from Indonesia
Alfano, niccolo; Michaux, Johan ULg; Fabre, Pierre-Henri et al

in Journal of Virology (2016)

Gibbon ape leukemia virus (GALV) and koala retrovirus (KoRV) most likely originated froma cross-species transmission of an ancestral retrovirus into koalas and gibbons via one or moreintermediate as yet ... [more ▼]

Gibbon ape leukemia virus (GALV) and koala retrovirus (KoRV) most likely originated froma cross-species transmission of an ancestral retrovirus into koalas and gibbons via one or moreintermediate as yet unknown hosts. A highly similar virus to GALV has been identified in anAustralian rodent (Melomys burtoni) after extensive screening of Australian wildlife. GALV-likeviruses have also been discovered in several Southeast Asian species although screening has not beenextensive and viruses discovered to date are only distantly related to GALV. We therefore screened 26Southeast Asian rodent species for KoRV- and GALV-like sequences, using hybridization capture andhigh-throughput sequencing, in the attempt to identify potential GALV and KoRV hosts. Only onespecies, an undescribed species of Melomys from Indonesia, was positive yielding an endogenousprovirus very closely related to a strain of GALV. The sequence of the critical receptor domain forGALV infection in the Indonesian Melomys sp. was consistent with the susceptibility of the species toGALV infection. The discovery of a GALV in a second Melomys species provides further evidencethat Melomys may play a role in the spread of GALV-like viruses, especially since the genus is foundin Indonesia, Papua New Guinea and Australia, connecting the home ranges of koalas and gibbons [less ▲]

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See detailAn endogenous gibbon ape leukemia virus (GALV) identified in a rodent (Melomys sp.) from Indonesia
Niccolo, Alfano; Michaux, Johan ULg; Fabre, pierre-Henri et al

in Journal of Virology (2016), sous presse

ABSTRACT Gibbon ape leukemia virus (GALV) and koala retrovirus (KoRV) most likely originated from a cross-species transmission of an ancestral retrovirus into koalas and gibbons via one or more ... [more ▼]

ABSTRACT Gibbon ape leukemia virus (GALV) and koala retrovirus (KoRV) most likely originated from a cross-species transmission of an ancestral retrovirus into koalas and gibbons via one or more intermediate as yet unknown hosts. A highly similar virus to GALV has been identified in an Australian rodent (Melomys burtoni) after extensive screening of Australian wildlife. GALV-like viruses have also been discovered in several Southeast Asian species although screening has not been extensive and viruses discovered to date are only distantly related to GALV. We therefore screened 26 Southeast Asian rodent species for KoRV- and GALV-like sequences, using hybridization capture and high-throughput sequencing, in the attempt to identify potential GALV and KoRV hosts. Only one species, an undescribed species of Melomys from Indonesia, was positive yielding an endogenous provirus very closely related to a strain of GALV. The sequence of the critical receptor domain for GALV infection in the Indonesian Melomys sp. was consistent with the susceptibility of the species to GALV infection. The discovery of a GALV in a second Melomys species provides further evidence that Melomys may play a role in the spread of GALV-like viruses, especially since the genus is found in Indonesia, Papua New Guinea and Australia, connecting the home ranges of koalas and gibbons. IMPORTANCE The gibbon ape leukemia virus (GALV) and the koala retrovirus (KoRV) are very closely related, yet their hosts are neither closely related nor overlap geographically. Direct cross-species infection between koalas and gibbons is unlikely. Therfore, GALV and KoRV may have arisen via a cross-species transfer from an intermediate host that overlaps in range with both gibbons and koalas. Using hybridization capture and high-throughput sequencing, we have screened a wide range of rodent candidate hosts from Southeast Asia for KoRV- and GALV-like sequences. Only a Melomys species from Indonesia was positive for GALV. We report the genome sequence of this newly identified GALV, the critical domain for infection of its potential cellular receptor and its phylogenetic relationships with the other previously characterized GALVs. We hypothesize that the genus Melomys may have played a key role in cross-species transmission to other taxa. [less ▲]

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See detailEndogenous Glutamate Involvement in Pulsatile Secretion of Gonadotropin-Releasing Hormone: Evidence from Effect of Glutamine and Developmental Changes
Bourguignon, Jean-Pierre ULg; Gerard, Arlette ULg; Alvarez Gonzalez, Maria-Luz ULg et al

in Endocrinology (1995), 136(3), 911-6

The secretion of GnRH can be stimulated by glutamate (GLU) and GLU agonists, whereas GLU receptor antagonists inhibit GnRH. Using 6-diazo-5-oxo-L-norleucine (DON), an inhibitor of glutaminase, we aimed to ... [more ▼]

The secretion of GnRH can be stimulated by glutamate (GLU) and GLU agonists, whereas GLU receptor antagonists inhibit GnRH. Using 6-diazo-5-oxo-L-norleucine (DON), an inhibitor of glutaminase, we aimed to study the involvement of endogenous GLU in GnRH secretion through the effects of impaired GLU biosynthesis from its precursor glutamine (GLN). GnRH secretion by hypothalamic explants of male rats, aged 15 and 50 days, was compared, because the frequency of spontaneous GnRH secretory pulses showed a 2-fold increase between those two ages. Using explants of 50-day-old rats, GLN elicited GnRH secretion in a similar dose-related manner as GLU. DON prevented GLN-evoked secretion of GnRH, whereas the effect of GLU was not altered. DON also markedly inhibited spontaneous pulsatile secretion of GnRH and the secretory response to veratridine, a Na+ channel opener. The inhibitory effect of DON on veratridine-evoked secretion of GnRH was directly related to the duration of exposure to DON and the frequency of GnRH secretory episodes. Using explants of 15-day-old rats, GLN could elicit GnRH release, although this response was lower than GLU-evoked secretion of GnRH. The DON concentrations required for inhibition of veratridine-evoked secretion of GnRH were lower at 15 days than at 50 days. These data indicate that 1) GLU biosynthesis from GLN is a prerequisite to the physiological mechanism of pulsatile GnRH secretion; and 2) inhibition of veratridine- or GLN-induced secretion of GnRH requires higher DON concentrations after the onset of puberty than before. This suggests that glutaminase, the enzyme controlling GLU biosynthesis from GLN, shows increased activity after the onset of puberty when the frequency of pulsatile GnRH secretion is increased as well. [less ▲]

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See detailEndogenous Growth and Regional Dynamics in an OLG Model with Land
Artige, Lionel ULg

Conference (2000, June)

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See detailEndogenous growth and regional dynamics in an OLG model with land
Artige, Lionel ULg

Conference (2001, November)

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See detailEndogenous Growth in an OLG Model with a Fixed Factor
Artige, Lionel ULg

E-print/Working paper (2010)

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See detailEndogenous mode of competition in general equilibrium
Tharakan, Joseph ULg

Conference (2005, November)

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See detailEndogenous mode of competition in general equilibrium
Tharakan, Joseph ULg

Conference (2006, November)

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See detailEndogenous mode of competition in general equilibrium
Tharakan, Joseph ULg

Conference (2009, March)

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See detailEndogenous mode of competition in general equilibrium
Tharakan, Joseph ULg

Conference (2011, October)

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See detailEndogenous mode of competition in general equilibrium
Tharakan, Joseph ULg

Conference (2007, May)

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See detailEndogenous mode of competition in general equilibrium
Tharakan, Joseph ULg

Conference (2010, December)

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See detailEndogenous murine leukemia retroviral variation across wild European and inbred strains of house mouse
Hartmann, Stephanie; Hasenkamp, Natasha; Mayer, Jens et al

in BMC Genomics (2015), DOI 10.1186/s12864-015-1766-z

Background: Endogenous Q1 murine leukemia retroviruses (MLVs) are high copy number proviral elements difficult to comprehensively characterize using standard low throughput sequencing approaches. However ... [more ▼]

Background: Endogenous Q1 murine leukemia retroviruses (MLVs) are high copy number proviral elements difficult to comprehensively characterize using standard low throughput sequencing approaches. However, high throughput approaches generate data that is challenging to process, interpret and present. 8 9 10 Results: Next generation sequencing (NGS) data was generated for MLVs from two wild caught Mus musculus domesticus (from mainland France and Corsica) and for inbred laboratory mouse strains C3H, LP/J and SJL. Sequence reads were grouped using a novel sequence clustering approach as applied to retroviral sequences. A Markov cluster algorithm was employed, and the sequence reads were queried for matches to specific xenotropic (Xmv), polytropic (Pmv) and modified polytropic (Mpmv) viral reference sequences. 11 12 13 14 15 Conclusions: Various MLV subtypes were more widespread than expected among the mice, which may be due to the higher coverage of NGS, or to the presence of similar sequence across many different proviral loci. The results did not correlate with variation in the major MLV receptor Xpr1, which can restrict exogenous MLVs, suggesting that endogenous MLV distribution may reflect gene flow more than past resistance to infection. [less ▲]

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See detailEndogenous nitric oxide modulates acetylcholine-induced edema and vasoconstriction in isolated perfused rabbit lungs.
Delaunois, Annie ULg; Gustin, Pascal ULg; Ansay, Michel ULg

in Journal of Pharmacology and Experimental Therapeutics (The) (1995), 274(2), 559-97

The modulatory role of endogenous nitric oxide (NO) on pulmonary edema induced by acetylcholine (ACh), capsaicin, substance P (SP) and 5-hydroxytryptamine (5-HT) was investigated by using an inhibitor of ... [more ▼]

The modulatory role of endogenous nitric oxide (NO) on pulmonary edema induced by acetylcholine (ACh), capsaicin, substance P (SP) and 5-hydroxytryptamine (5-HT) was investigated by using an inhibitor of NO synthase, N-omega-nitro-L-arginine (L-NNA). The effects of endogenous NO on the hemodynamic response to ACh, 5-HT and SP were also investigated. The capillary filtration coefficient (Kf,c), the total pressure gradient (delta Pt) and its four components [arterial (delta Pa), pre- (delta Pa') and post-capillary (delta Pv'), and venous gradient (delta Pv)] were evaluated on isolated, ventilated, perfused rabbit lungs. ACh (10(-8) to 10(-4) M) and SP (10(-10) to 10(-6) M) induced a concentration-dependent increase in the Kf,c. Capsaicin (10(-4) M) and 5-HT (10(-4) M) also increased this parameter. L-NNA (10(-4) M) completely inhibited the effects of ACh and capsaicin on the Kf,c, without preventing the effects of SP and 5-HT. ACh induced a concentration-dependent vasoconstriction in the precapillary segment. Pretreatment with L-NNA enhanced this increase in delta Pa' but also increased delta Pv' and delta Pv. 5-HT increased delta Pt and delta Pa proportionally to the concentration. This effect was enhanced by L-NNA, which also increased delta Pa'. SP had no significant hemodynamic effect. Pretreatment with L-NNA did not modify the response to SP. Sodium nitroprusside (10(-5) M) induced a left shift of the concentration-response curve to ACh on the Kf,c, although it did not change the response to SP. Sodium nitroprusside also inhibited the hemodynamic effect of ACh. It was concluded that endogenous NO is involved in ACh-and capsaicin-induced edema via a prejunctional stimulatory effect on the C-fibers. Endogenous NO can also modulate ACh- and 5-HT-induced vasoconstriction by exerting a vasodilator action on the whole pulmonary vascular bed. [less ▲]

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See detailEndogenous nitric oxide production and atrial natriuretic peptide biological activity in infants undergoing cardiac operations
Seghaye, Marie-Christine ULg; Duchateau, J.; Bruniaux, J. et al

in Critical Care Medicine (1997), 25(6), 1063-1070

Objectives: To examine whether preoperative heart failure end cardiac surgery influence nitric oxide production and atrial natriuretic peptide (ANP) biological activity in infants and whether nitric oxide ... [more ▼]

Objectives: To examine whether preoperative heart failure end cardiac surgery influence nitric oxide production and atrial natriuretic peptide (ANP) biological activity in infants and whether nitric oxide and ANP participate in the control of postoperative pulmonary vascular tone. Design: Prospective, clinical study. Setting: Tertiary pediatric cardiac intensive care unit in a referral cardiosurgical center. Patients: Nineteen infants (median age 4 months) undergoing cardiac surgery: 13 infants with ventricular or atrioventricular septal defect associated with heart failure and pulmonary hypertension (group 1); and six infants with tetralogy of Fallot, without heart failure (group 2). Interventions: Blood samples obtained from indwelling catheters or bypass circuit outlets. Measurements and Main Results: Nitrite and nitrate blood concentrations (as a marker for nitric oxide synthesis) and the molar ratio of cyclic guanosine 3',5'-monophosphate (cGMP) to ANP (as a marker for ANP biological activity) were determined before, during, and up to 24 hrs after cardiopulmonary bypass (CPB). In group 1 patients, these biological parameters were related to postoperative pulmonary arterial pressure. Preoperative nitrite and nitrate concentrations were higher in group 1 patients than in group 2 patients (p < .02), and this difference persisted during CPB. Nitrite and nitrate concentrations 24 hrs postoperatively were lower than preoperative values in group 1 patients (p < .05) end were unchanged in group 2 patients. An inverse correlation was observed postoperatively between nitrite and nitrate concentrations and systolic pulmonary arterial pressure (r2 = 0.4, p < .05). Group 1 patients had a lower preoperative cGMP/ANP ratio than group 2 patients (p < .05), despite higher ANP levels (p < .005). The cGMP/ANP ratio decreased during CPB in both groups (p < .0001), and in group 2 patients, cGMP and ANP values remained below preoperative values ≤24 hrs postoperatively. A correlation was observed between ANP levels and systolic pulmonary arterial pressure 2 and 4 hrs postoperatively (r2 = .4, p < .05, respectively), but no correlation was observed between ANP biological activity and postoperative pulmonary arterial pressure. Conclusions: Infants with heart failure and pulmonary hypertension have increased nitric oxide synthesis and decreased ANP biological activity; both phenomena may be involved in the pathophysiology of this clinical condition. CPB has no detectable effect on nitric oxide production but does decrease ANP biological activity. In patients with preoperative heart failure and pulmonary hypertension, endogenous nitric oxide appears to play a role in the control of postoperative pulmonary vascular tone. [less ▲]

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See detailEndogenous Production of Specific Antibodies Does Not Decrease Hypocalcemic Response to Calcitonin in Young Rabbits
Reginster, Jean-Yves ULg; Azria, M.; Lismonde, Stéphanie ULg et al

in Calcified Tissue International (1992), 50

In order to evaluate the potential inhibition of the acute anti-osteoclastic activity of salmon calcitonin (SCT) by specific antibodies (Ab), we compared the SCT-induced hypocalcemic effect in young male ... [more ▼]

In order to evaluate the potential inhibition of the acute anti-osteoclastic activity of salmon calcitonin (SCT) by specific antibodies (Ab), we compared the SCT-induced hypocalcemic effect in young male rabbits with significant titers of high affinity Ab and in matched animals without Ab. Immunization of rabbits was performed by repetitive s.c. injections of SCT and Freund adjuvant. Ab were present in four-fifths of SCT-treated rabbits (Ab+). Their titer varied from 0.8 x 10(-9) to 30 x 10(-9) M/liter and their constant of affinity from 0.97 x 10(9) to 4.2 x 10(9) L/M. Intravenous injection of 1 IU/kg SCT to Ab+ rabbits induced a significant decrease (P less than 0.01) of ionized serum calcium (Ca2+) after 30 minutes (mean +/- SD: -9 +/- 0.6%) and until the 240th minute of the test (-16.7 +/- 4.7%), with a maximum after 120 minutes (-22.6 +/- 2%). This was not significantly different from the hypocalcemic effect measured after the same procedure performed in matched animals without Ab (Ab-): significant decrease in Ca2+ (P less than 0.01) after 30 minutes (-8.2 +/- 2.2%), maximal after 150 minutes (-23.2 +/- 4.9%), and lasting until 210 minutes (-14.5 +/- 3.7%). We conclude that, in the particular model of the male young rabbit, specific anti-SCT Ab do not block or reduce the acute anti-osteoclastic activity of SCT. [less ▲]

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See detailEndogenous reproductive hormones and nocturnal rhythms in partner preference and sexual behavior of ATD-treated male rats.
Bakker, Julie ULg; van Ophemert, J.; Timmerman, M. A. et al

in Neuroendocrinology (1995), 62(4), 396-405

Male rats received subcutaneously silastic capsules, containing the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD), shortly after birth. Control males were given silastic capsules containing ... [more ▼]

Male rats received subcutaneously silastic capsules, containing the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD), shortly after birth. Control males were given silastic capsules containing cholesterol. The capsules were removed at the age of 21 days. In adulthood, blood serum was collected early and late in the dark phase of the light/dark cycle (experiment I). Testosterone and luteinizing hormone and follicle stimulating hormone (FSH) fluctuated nocturnally, both in ATD and control males, with highest levels late in the dark phase. FSH levels were significantly higher in ATD males. Nocturnal levels of inhibin, a selective suppressor of pituitary FSH secretion, also fluctuated in both ATD and control males, with lowest levels late in the dark phase. In experiment II, ATD and control males were tested for partner preference behavior in a three-compartment box (choice: sexually active male vs. estrous female) early and late in the dark phase. When gonadally intact, ATD males, but not controls, showed a clear nocturnal rhythmicity in partner preference behavior and sexual behavior. Early in the dark phase, such ATD males preferred the vicinity of and interaction with a sexually active male. Late in the dark phase, this preference for the active male shifted to a preference for the estrous female. Control males preferred the estrous female. After castration and subsequent treatment with testosterone via silastic capsules, which ensured constant blood serum levels, ATD males continued to show their nocturnal rhythms in partner preference behavior and in sexual behavior. Thus, the underlying mechanism of the nocturnal rhythmicity phenomenon is an organizational effect of neonatal ATD treatment rather than an activational effect of fluctuating serum hormone levels. [less ▲]

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See detailEndogenous substrate oxidation during exercise and variations in breath 13CO2/12CO2.
Gautier, J. F.; Pirnay, Freddy ULg; Jandrain, Bernard ULg et al

in Journal of Applied Physiology (Bethesda, Md. : 1985) (1993), 74(1), 133-8

This study attempted to induce a major shift in the utilization of endogenous substrates during exercise in men by the use of a potent inhibitor of adipose tissue lipolysis, Acipimox, and to see to what ... [more ▼]

This study attempted to induce a major shift in the utilization of endogenous substrates during exercise in men by the use of a potent inhibitor of adipose tissue lipolysis, Acipimox, and to see to what extent this affects the 13C/12C ratio in expired air CO2. Six healthy volunteers exercised for 3 h on a treadmill at approximately 45% of their maximum O2 uptake, 75 min after having ingested either a placebo or 250 mg Acipimox. The rise in plasma free fatty acids and glycerol was almost totally prevented by Acipimox, and no significant rise in the utilization of lipids, evaluated by indirect calorimetry, was observed. Total carbohydrate oxidation averaged 128 +/- 17 (placebo) and 182 +/- 21 g/3 h (Acipimox). Conversely, total lipid oxidation was 84 +/- 5 (placebo) and 57 +/- 6 g/3 h (Acipimox; P < 0.01). Under placebo, changes in expired air CO2 delta 13C were minimal, with only a 0.49/1000 significant rise at 30 min. In contrast, under Acipimox, the rise in expired air CO2 delta 13C averaged 1/1000 and was significant throughout the 3-h exercise bout; in these conditions calculation of a "pseudooxidation" of an exogenous sugar naturally or artificially enriched in 13C, but not ingested, would have given an erroneous value of 19.8 +/- 2.6 g/3 h. Thus under conditions of extreme changes in endogenous substrate utilization, an appropriate control experiment is mandatory when studying exogenous substrate oxidation by 13C-labeled substrates and isotope-ratio mass spectrometry measurements on expired air CO2. [less ▲]

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See detailEndogenous versus exogenous markers of adult neurogenesis in canaries and other birds: advantages and disadvantages.
Balthazart, Jacques ULg; Ball, Gregory F.

in The Journal of comparative neurology (2014), 522(18), 4100-20

Although the existence of newborn neurons had originally been suggested, but not broadly accepted, based on studies in adult rodent brains, the presence of an active neurogenesis process in adult ... [more ▼]

Although the existence of newborn neurons had originally been suggested, but not broadly accepted, based on studies in adult rodent brains, the presence of an active neurogenesis process in adult homoeothermic vertebrates was first firmly established in songbirds. Adult neurogenesis was initially studied with the tritiated thymidine technique, later replaced by the injection and detection of the marker of DNA replication 5-bromo-2'-deoxyuridine (BrdU). More recently, various endogenous markers were used to identify young neurons or cycling neuronal progenitors. We review here the respective advantages and pitfalls of these different approaches in birds, with specific reference to the microtubule-associated protein, doublecortin (DCX), that has been extensively used to identify young newly born neurons in adult brains. All these techniques of course have limitations. Exogenous markers label cells replicating their DNA only during a brief period and it is difficult to select injection doses that would exhaustively label all these cells without inducing DNA damage that will also result in some form of labeling during repair. On the other hand, specificity of endogenous markers is difficult to establish due to problems related to the specificity of antibodies (these problems can be, but are not always, addressed) and more importantly because it is difficult, if not impossible, to prove that a given marker exhaustively and specifically labels a given cell population. Despite these potential limitations, these endogenous markers and DCX staining in particular clearly represent a useful approach to the detailed study of neurogenesis especially when combined with other techniques such as BrdU. [less ▲]

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