Eugenol for anesthesia of African clawed frogs (Xenopus laevis)

OBJECTIVE: To determine the level of anesthesia attained in Xenopus laevis frogs with eugenol at different doses and by different routes of administration. STUDY DESIGN: Prospective experimental trial. ANIMALS: Sixty X. laevis nonbreeding female frogs weighing between 90 and 140 g. METHODS: Three different routes of administration were tested - subcutaneous injections into the dorsal lymph sacs, topical administration using a gauze patch, and immersion in a bath containing eugenol. Following the determination of the best route of administration, the acetic acid test, the withdrawal reflex, righting reflex, heart rate, and respiratory frequency were used to evaluate central nervous system depression following eugenol bath administration. In an additional group, the response to a surgical incision of the abdominal wall was evaluated. The pharmacokinetics of eugenol were determined following bath immersion administration, and pharmacokinetic parameters were calculated following blood concentration determination by tandem liquid chromatography/mass spectrometry analyses. RESULTS: It was not possible to induce anethesia with subcutaneous and patch administration, independent of the eugenol dose administered. The immersion bath was the only efficacious route for anesthesia inducing surgical anesthesia for at least 30 minutes with postoperative analgesia. Histopathology of selected tissues (heart, lung, liver, kidneys, eyes) showed no evidence of lesions 24 hours following bath immersion. The elimination half-life (T(1/2)) was 4 hours. CONCLUSIONS: When administered as a single-bath immersion (dose 350 mg L(-1)) for 15 minutes, eugenol may serve as an effective anesthetic in X. laevis frogs for short surgical procedures.     

Case of cutaneous necrosis in African clawed frogs Xenopus laevis after the topical application of eugenol

Case of cutaneous necrosis in African Clawed frogs Xenopus laevis after the topical application of eugenol. African Clawed frogs showed necrotic cutaneous lesions after a topical application of high concentrations of eugenol, an analgesic and anesthetic agent. Microscopically, ulceration of the epidermis, a loss of mucous and serous glands as well as an infiltration of inflammatory cells were observed.     

Mycobacterium szulgai infection in a captive population of African clawed frogs (Xenopus tropicalis).

A colony of captive Xenopus tropicalis became infected with Mycobacterium szulgai. Clinical signs, when observed, were lethargy, weight loss, and emaciation. Visceral granulomas were common findings at laparoscopy and necropsy. The diagnosis of mycobacteriosis was based on histologic appearance and Ziehl-Neelsen staining of tissues. The identification of M. szulgai organisms was based on comparison of the 16S rRNA gene sequence with several GenBank databases. There have been no reports of this mycobacterial species as the causative agent of naturally occurring disease in amphibians.     

Mycobacterium gordonae as potential cause of granulomatous lesions of the toe tips in the South African clawed frog (Xenopus laevis)

During regular health status monitoring of the colony of amphibian, Mycobacterium (M.) gordonae were isolated from granulomatous lesions of the tiptoes from the South African clawed frog (Xenopus laevis) maintained at the Tierforschungszentrum of the University of Ulm. During a period of three years a total of 21 animals of the colony, consisting of 350-400 frogs, showed granuloma of the tip of the toes and a loss of the claws. The general condition and the behavior of the frogs appeared to be unchanged. Using a selective medium one isolate was cultured and identified by sequencing of the 16S rRNA gene. To apply a rapid diagnostic method for detecting mycobacteria, in particular M. gordonae in the health monitoring programme of the Xenopus laevis colony, we established the rpoB gene PCR followed by HaeIII restriction analysis of the PCR product. We identified M. gordonae from granuloma of the tiptoes and from unaltered tissue samples of the lungs and skin by PCR restriction analysis. Since mycobacterial species apparently are widespread in granulomatous lesions of the tiptoes of Xenopus laevis, we hypothesize a pathogenic potential. This view is supported by an increasing number of reports in the literature on infections with nontuberculous, "non-pathogenic" mycobacteria in Xenopus laevis.     

Oral immunization of the African clawed frog (Xenopus laevis) upregulates the mucosal immunoglobulin IgX

The frog Xenopus laevis is a model species for developmental biology but is also of significant interest to comparative immunologists. Amphibians are the oldest group of organisms in which both the B lymphocytes of some species undergo immunoglobulin (Ig) class switch recombination and also have a dedicated mucosal Ig isotype. The purpose of this study was to test the hypothesis that frog IgX would be produced in response to oral immunization. In order to facilitate studies of humoral, and especially mucosal immunity, in this model species, we developed a gavage technique for oral immunization. The result of this oral administration of antigen to frogs was assayed by the induction of the mucosal antibody isotype, IgX, in plasma by enzyme linked immunosorbant assay (ELISA), and a significant IgX upregulation was detected compared to frogs receiving systemic immunization into the coelom. These data are consistent with the view that IgX is the functional analog of mammalian IgA and mandate further studies of the relationship between IgX and IgA. Additionally, the gavage technique should be adaptable for functional studies of gut-associated immunology in other small aquatic vertebrates.     

Expression patterns of glycoconjugates in the three distinctive olfactory pathways of the clawed frog, Xenopus laevis

Xenopus laevis has three distinctive olfactory neuroepithelia. We examined the axonal projection from each of these epithelia to the olfactory bulb by Di-I labeling, and confirmed that the Xenopus primary olfactory pathways involve the dorsal pathway from the olfactory epithelium to the dorsal region of the main olfactory bulb, the ventral pathway from the middle chamber epithelium to the ventral region of the main olfactory bulb, and the vomeronasal pathway from the vomeronasal epithelium to the accessory olfactory bulb. We next examined expression patterns of glycoconjugates in the three olfactory pathways by lectin-histochemistry using 21 biotinylated lectins. Fourteen out of 21 lectins stained the Xenopus primary olfactory system. RCA-I stained the three olfactory pathways uniformly. PHA-E stained only the dorsal pathway. LEL, STL, PNA, ECL and UEA-I stained the dorsal pathway more intensely than the ventral pathway, and among them, only UEA-I stained the vomeronasal pathway. In contrast, s-WGA, DBA, SBA, BSL-I VVA, SJA and PHA-L showed intense stainings in the ventral pathway and moderate stainings in the vomeronasal pathway, but faint or weak stainings in the dorsal pathway. These observations suggest that the ventral pathway expresses glycoconjugates shared commonly with either the dorsal or the vomeronasal pathway. In addition, from the binding patterns of the lectins with a binding specificity for N-acetylgalactosamine, glycoconjugates containing this saccharide seem to play an important role for the organization of the olfactory pathways.     

Propagation method of saving valuable strains from a Mycobacterium liflandii infection in Western clawed frogs (Silurana tropicalis)

Mycobacterium liflandii has been responsible for an emerging infection reported in the international trade of Western clawed frogs (Silurana tropicalis). This study shows that this mycolactone-producing Mycobacterium (MPM) has expanded its distribution range to France. The results of this study suggest that the use of in vitro fertilization to maintain genetic lines could be a temporary solution for valuable S. tropicalis propagation.     

Glomerulonephritis and anasarca in a colony of frogs.

A colony of frogs experienced excessive mortality due to glomerulonephritis. The presenting symptom in all cases was bloating due to hydrocoelom and anasarca. Mycobacteria sp was suspected to be a source of chronic antigenic stimulation that resulted in the glomerulonephritis. The prognosis was grave once symptoms appeared. Histopathology from some of the affected frogs is described, and mycobacterial disease in amphibians is discussed.     

Bilateral ocular anomalies in a South African fur seal (Arctocephalus pusillus pusillus)

A female South African fur seal (Arctocephalus pusillus pusillus) began having obvious clinical ophthalmologic problems by 8 weeks of age. The initial clinical sign was diffuse corneal edema, which progressed to bullae formation and ulcers; the underlying cause of corneal edema and bullous keratopathy was not identified antemortem. An ophthalmological evaluation was performed when the fur seal was approximately 6 months of age, but due to the diffuse corneal edema, intraocular structures could not be easily evaluated. An underlying infectious etiology was suspected; therefore, appropriate diagnostics were pursued, but did not identify a cause. Initial improvement was noted, but the fur seal then became blind and eventually became very painful. Due to decreased quality of life and aggressive behavior, the fur seal was euthanized. Histopathological diagnoses were persistent tunica vasculosa lentis and persistent hyperplastic primary vitreous with bilateral hypermature resorbed cataracts and retinal detachments with rosette formation.     

Cytosystematics of the South African Aethomys (Rodentia: Muridae)

The G-and C-band chromosome patterns and the location of the nucleolus organizer regions (NORs) are presented for A. namaquensis (2n = 24), A. granti (2n = 32) and A. chrysophilus (2n = 44; 2n = 50). The presence of two distinct cytotypes in what is conventionally recognized as A. chrysophilus is indicative of the presence of two discrete species which, karyology apart, appear to be indistinguishable using existing identification keys. The chromosomal relationships of the South African species and the taxonomic implications of these data are discussed.     

Occurrence of avian Schistosomatidae (Trematoda) in South African birds as determined by a faecal survey

The abundance, prevalence and distribution of avian Schistosomatidae in South African birds has been estimated by means of a survey for parasite eggs in faecal samples. Eight types of eggs were recovered, mostly from members of the Anatidae and Laridae and these have been assigned to the following schistosome genera: Austrobilharzia (1), Gigantobilharzia (1), Trichobilharzia (5) and Ornithobilharzia (1).     

Invasion of a South African Anguilla mossambica (Anguillidae) opulation by the alien gill worm Pseudodactylogyrus anguillae (Monogenea)

The parasitic gill monogenean Pseudodactylogyrus anguillae is alien to Africa. In an investigation of 227 longfin eel, Anguilla mossambica, and 26 mottled eel, Anguilla marmorata, sampled from four river systems in the Eastern Cape, South Africa, this parasite was only present on the gills of A. mossambica sampled from the Great Fish River system. In the Great Fish River, it infected 73.2% of the sampled population at a mean intensity of 63.8±34.3 parasites per fish. High prevalence and intensity are indicative of a well-established alien invasive parasitic species. Results showing the absence of P. anguillae from the co-occurring but less abundant A. marmorata indicate that this species may be less susceptible to P. anguillae infection.     

光滑爪蟾皮肤抗菌肽的分离纯化及活性检测

通过高效液相色谱法,对光滑爪蟾皮肤分泌物进行分离纯化,得到具有抗菌活性的光滑爪蟾皮肤抗菌肽。通过最小抑菌浓度（MIC）试验、溶血活性试验及癌细胞抑制试验,对其体外生物活性进行研究。结果表明,经过纯化得到2个纯度高且具有活性的抗菌肽（AMP1和AMP2）,质谱鉴定结果得出其相对分子质量分别为1 082.78和2237.34。MIC结果表明,AMP1对S.aureus ATCC25923、Escherichia coli ATCC25922的MIC值分别为23.63、8.71mg/L,对MRSA无抑菌作用。AMP2对S.aureus ATCC25923,Escherichia coli ATCC25922、MRSA的MIC值分别为4.94、10.7、86.6mg/L。溶血试验显示AMP1,AMP2具有极弱溶血活性,且对癌细胞SW480具有抑制作用。     

New Records of Ocnerodrilidae and Lumbricidae (Oligochaeta) from South African Rivers

The columella amis in Crocodilus niloticus has been found to comprise the two upper segments of the hyoid arch, viz., a forked pharyngohyal and an epihyal. To these two primary arch divisions becomes added a laterohyal component derived from delaminating subepidermal blasteme. The crocodilian stapes represents the infrapharyngohyal; the suprastapedial stem (or basal portion of the lacertilian dorsal process) represents the suprapharyngohyal while the extrastapedial represents essentially the epihyal to which laterohyal material contributes the tympanic process as well as the suprastapedial (or lacertilian intercalary). The lateral limb of the so-called lateral prong of the reptilian and avian columella auris is also a laterohyal derivative. It is concluded that in reptiles and birds: (a) the lateral limb and intercalary represent the dorsal articular head of the rhipidistian hyomandibula, (b) the proximal end of the epihyal represents its ventral articular head and (c) the so-called Huxley's foramen is the original passage between the two. Since the lacertilian internal process arises from the pharyngohyal it cannot represent the original rhipidistian quadrate-hyomandibular articulation.