Intrahost distribution and transmission of a new species of cyclopoid copepod endosymbiotic to a freshwater snail, Pomacea canaliculata (Caenogastropoda, Ampullariidae), from Argentina.

A new species of cyclopoid copepod, Ozmana huarpium, is described as a symbiont to Pomacea canaliculata (Lamarck 1822) (Caenogastropoda, Ampullariidae). Rather large numbers (about one hundred copepods per snail) were found, although there was no evidence of harm to the host. To our knowledge, O. haemophila (symbiont to P. maculata), and the currently described species, O. huarpium, are the only copepod species ever recorded as endosymbionts to freshwater invertebrates. While O. haemophila is restricted to the haemocoel of its host, O. huarpium predominate in the penis sheath, the ctenidium and the mantle cavity, figuring in these pallial organs 63-65% of total mature forms. The sex ratio of the symbiont is skewed to the female side in these organs, specially in male hosts. The hypothesis that a special female tropism for the male host's pallial organs might ensure interindividual transmission of the symbiont was tested, with indications that the symbiont is mainly transmitted during copulation.

Intrahost distribution and trasmission of a new species of cyclopoid copepod endosymbiotic to a freshwater snail, Pomacea canaliculata (Caenogastropoda, Ampullariidae), from Argentina

A new species of cyclopoid copepod, Ozmana huarpium, is described as a symbiont to Pomacea canaliculata (Lamarck 1822) (Caenogastropoda, Ampullariidae). Rather large numbers (about one hundred copepods per snail)were found, althought there was no evidence of harm to the host. To our knowledge, O. haemophila (symbiont to P. maculata), and the currently described species, O. huarpium, are the only copepod species ever recorded as endosymbionts to freshwater invertebrates. While O. haemophila is restricted to the haemocoel of its host, O. harpium predominate in the penis sheath, the ctenidium and the mantle cavity, figuring in these pallial organs 63-65 por ciento of total mature forms. The sex ratio of the symbiont is skewed to the female side in these organs, specially in male hosts. The hypothesis that a special female tropism for the male host´s pallial organs might ensure interindividual transmission of the symbiont was tested, with indications that the symbiont is mainly transmitted during copulation.

Synergistic effect of cortisol and thyrotrophin releasing hormone on lung maturation in the fetal sheep entails connective tissue maturation.

Pressure-volume relationships and collagen and elastin contents were measured in the lungs of fetal sheep infused either with saline (n = 4), thyrotrophin-releasing hormone (TRH; n = 6), cortisol (n = 9) or TRH plus cortisol (n = 10) at 128 days of gestation (term = 149 days) for 7 days. Lung distensibility (V40 = 1.8 +/- 0.1 ml/g wet wt; mean +/- SD) and stability (V5 = 0.6 +/- 0.1) increased along with collagen (C) (10.1 +/- 2.7 micrograms/mg) and elastin (E) contents (128 +/- 35 ng/mg) in the animals infused with TRH plus cortisol and were significantly higher (p < 0.05) than those observed in TRH (V40 0.62 +/- 0.07; V5 0.32 +/- 0.04; C 3.53 +/- 1.3; E 38.2 +/- 8.3), cortisol (V4 0.66 +/- 0.6; V5 0.27 +/- 0.03; C 4.27 +/- 0.8; E 41.02 +/- 12.7) or saline infused fetuses (V40 0.40 +/- 0.1; V5 0.20 +/- 0.06; C 3.28 +/- 0.9; E 31.5 +/- 9.2). Plasma concentrations of prolactin (PRL), triiodothyronine (T3) and cortisol (F) were also higher in the group of fetuses infused with both hormones in comparison with the other groups. In fetuses treated with TRH plus cortisol, PRL (32 +/- 8.3 ng/ml) and T3 (308.3 +/- 36 micrograms/dl) were significantly higher than in those infused with cortisol alone (PRL 3.7 +/- 2.3; T3 128 +/- 30) or with saline (PRL 4.2 +/- 1.6; T3 < 5 micrograms/dl). In the group treated with TRH alone, PRL also increased significantly (37 +/- 6.4), but T3 increased only slightly (18 +/- 3.4).(ABSTRACT TRUNCATED AT 250 WORDS)