Phylogenetic analyses of Chilomastix and Retortamonas species using in vitro excysted flagellates.

In vitro excystation of cysts of microscopically identified Chilomastix mesnili and Retortamonas sp. isolated from Japanese macaques and Retortamonas sp. isolated from small Indian mongooses could be induced using an established protocol for Giardia intestinalis and subsequently by culturing with H2S-rich Robinson's medium supplemented with Desulfovibrio desulfuricans. Excystation usually began 2 h after incubation in Robinson's medium. DNA was isolated from excysted flagellates after 4 h of incubation or from cultured excysted flagellates. Phylogenetic analysis based on their 18S rRNA genes revealed that two isolates of C. mesnili from Japanese macaques belonged to the same cluster as a C. mesnili isolate from humans, whereas a mammalian Retortamonas sp. isolate from a small Indian mongoose belonged to the same cluster as that of an amphibian Retortamonas spp. isolate from a 'poison arrow frog' [sequence identity to AF439347 (94.9%)]. These results suggest that the sequence homology of the 18S rRNA gene of the two C. mesnili isolates from Japanese macaques was similar to that of humans, in addition to the morphological similarity, and Retortamonas sp. infection of the amphibian type in the small Indian mongoose highlighted the possibility of the effect of host feeding habitats.

Acute pancreatitis in slender-tailed meerkats (Suricata suricatta).

Four adult, full-sibling slender-tailed meerkats (Suricata suricatta) were diagnosed with acute pancreatitis. The incident case presented with lethargy, anorexia, abdominal guarding, and a cranial abdominal mass. Serum was grossly lipemic, with elevated cholesterol and triglyceride concentrations and increased amylase and lipase activity. An exploratory laparotomy confirmed chylous peritonitis and included excision of a saponified spleno-duodenal mass, a partial pancreatectomy, and a splenectomy. Histopathology revealed severe, multifocal, subacute necrotizing and granulomatous pancreatitis. Within 13 days of the incident case, the second meerkat was identified with essentially identical clinical, surgical, and histologic findings. During subsequent physical examinations of apparently unaffected cohorts (n=12), physical and hematologic findings suggestive of pancreatitis were identified in the two remaining siblings of the first two cases. The definitive cause for these four cases is undetermined; however, common risk factors identified were obesity and hyperlipidemia, a change to a higher-fat diet, and genetic predisposition. To assess its usefulness in the diagnosis of meerkat pancreatitis, serum canine and feline pancreatic lipase immunoreactivity (cPLI and fPLI) concentrations were measured in serum samples (n=61) from two unrelated meerkat populations. Although these assays are highly sensitive and specific for the diagnosis of pancreatitis in domestic carnivores, similar correlation was not apparent for meerkats. In addition, hyperlipidemia was inconsistently present in many meerkats, with no apparent correlation to the development of clinical illness. Based on these observations, sensitive and specific diagnostic tests for pancreatitis in meerkats are currently unavailable.

Molecular systematics and origin of sociality in mongooses (Herpestidae, Carnivora).

The Herpestidae are small terrestrial carnivores comprising 18 African and Asian genera, currently split into two subfamilies, the Herpestinae and the Galidiinae. The aim of this work was to resolve intra-familial relationships and to test the origin of sociality in the group. For this purpose we analysed sequences of the complete cytochrome b gene for 18 species of Herpestidae. The results showed that the mongooses were split into three clades: (1) the Malagasy taxa (Galidiinae and Cryptoprocta), (2) the true social mongooses and (3) the solitary mongooses, each group being also supported by morphological and chromosomal data. Our results suggested unexpected phylogenetic relationships: (1) the genus Cynictis is included in the solitary mongoose clade, (2) the genera Liberiictis and Mungos are sister-group, and (3) the genus Herpestes is polyphyletic. We examined the evolution of the sociality in mongooses by combining behavioural traits with the cytochrome b data. Some of the behavioural traits provided good synapomorphies for characterizing the social species clade, showing the potential benefit of using such characters in phylogeny. The mapping of ecological and behavioural features resulted in hypothesizing solitary behavior and life in forest as the conditions at the base of the mongoose clade.

How the mongoose can fight the snake: the binding site of the mongoose acetylcholine receptor.

The ligand binding site of the nicotinic acetylcholine receptor (AcChoR) is within a short peptide from the alpha subunit that includes the tandem cysteine residues at positions 192 and 193. To elucidate the molecular basis of the binding properties of the AcChoR, we chose to study nonclassical muscle AcChoRs from animals that are resistant to alpha-neurotoxins. We have previously reported that the resistance of snake AcChoR to alpha-bungarotoxin (alpha-BTX) may be accounted for by several major substitutions in the ligand binding site of the receptor. In the present study, we have analyzed the binding site of AcChoR from the mongoose, which is also resistant to alpha-neurotoxins. It was shown that mongoose AcChoR does not bind alpha-BTX in vivo or in vitro. cDNA fragments of the alpha subunit of mongoose AcChoR corresponding to codons 122-205 and including the presumed ligand binding site were cloned, sequenced, and expressed in Escherichia coli. The expressed protein fragments of the mongoose, as well as of snake receptors, do not bind alpha-BTX. The mongoose fragment is highly homologous (greater than 90%) to the respective mouse fragment. Out of the seven amino acid differences between the mongoose and mouse in this region, five cluster in the presumed ligand binding site, close to cysteines 192 and 193. These changes are at positions 187 (Trp----Asn), 189 (Phe----Thr), 191 (Ser----Ala), 194 (Pro----Leu), and 197 (Pro----His). The mongoose like the snake AcChoR has a potential glycosylation site in the binding site domain. Sequence comparison between species suggests that substitutions at positions 187, 189, and 194 are important in determining the resistance of mongoose and snake AcChoR to alpha-BTX. In addition, it was shown that amino acid residues that had been reported to be necessary for acetylcholine binding are conserved in the toxin-resistant animals as well.

Identification and patterns of synapsis of the autosomally translocated Y-chromosome of the Indian mongoose, Herpestes auropunctatus (Hodgson).

The multiple sex chromosome system, X1X2Y male/X1X1X2X2 female, in the small Indian mongoose, Herpestes auropunctatus, results from a translocation of a part of Y chromosome to an autosome. It is not possible to distinguish the autosome which harbours the Y chromosome element in the somatic complement. By employing the surface-spreading technique to prophase I meiocytes we have identified the region to which the Y chromosome has been translocated as the short arm of chromosome 9 which is a subtelocentric chromosome. This Y chromosome component lacks heterochromatin and no sex vesicle is organised during meiotic prophase. This suggests to us that Y heterochromatin in mammals may be required for the production of a sex vesicle.