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Models of cardiac repair are needed to understand mechanisms underlying failure to regenerate in human cardiac tissue. Such studies are currently dominated by the use of zebrafish and mice. Remarkably, it is between these two evolutionary separated species that the adult cardiac regenerative capacity is thought to be lost, but causes of this difference remain largely unknown. Amphibians, evolutionary positioned between these two models, are of particular interest to help fill this lack of knowledge. We thus developed an endoscopy-based resection method to explore the consequences of cardiac injury in adult Xenopus laevis. This method allowed in situ live heart observation, standardised tissue amputation size and reproducibility. During the first week following amputation, gene expression of cell proliferation markers remained unchanged, whereas those relating to sarcomere organisation decreased and markers of inflammation, fibrosis and hypertrophy increased. One-month post-amputation, fibrosis and hypertrophy were evident at the injury site, persisting through 11 months. Moreover, cardiomyocyte sarcomere organisation deteriorated early following amputation, and was not completely recovered as far as 11 months later. We conclude that the adult Xenopus heart is unable to regenerate, displaying cellular and molecular marks of scarring. Our work suggests that, contrary to urodeles and teleosts, with the exception of medaka, adult anurans share a cardiac injury outcome similar to adult mammals. This observation is at odds with current hypotheses that link loss of cardiac regenerative capacity with acquisition of homeothermy.

Stable integration of foreign DNA into the frog genome has been the purpose of several studies aimed at generating transgenic animals or producing mutations of endogenous genes. Inserting DNA into a host genome can be achieved in a number of ways. In Xenopus, different strategies have been developed which exhibit specific molecular and technical features. Although several of these technologies were also applied in various model organizms, the attributes of each method have rarely been experimentally compared. Investigators are thus confronted with a difficult choice to discriminate which method would be best suited for their applications. To gain better understanding, a transgenesis workshop was organized by the X-omics consortium. Three procedures were assessed side-by-side, and the results obtained are used to illustrate this review. In addition, a number of reagents and tools have been set up for the purpose of gene expression and functional gene analyses. This not only improves the status of Xenopus as a powerful model for developmental studies, but also renders it suitable for sophisticated genetic approaches. Twenty years after the first reported transgenic Xenopus, we review the state of the art of transgenic research, focusing on the new perspectives in performing genetic studies in this species.

Three subspecies of banteng (Bos javanicus) have been described: B. j. javanicus in Java, B. j. lowi in Borneo, and B. j. birmanicus in Cambodia, Lao PDR, Myanmar, Thailand and Vietnam. In this paper we provide the first description of the karyotype of the Cambodian banteng. The chromosomal complement of B. j. birmanicus differs from that of B. j. javanicus, which was previously found to be similar to that of cattle, Bos taurus (2n = 60). The Cambodian banteng karyotype has a diploid number of 2n = 56 (FN = 62) and the karyotype consists of 26 pairs of acrocentric chromosomes and two pairs of submetacentric chromosomes. Comparisons with other species of the subtribe Bovina show that the two pairs of bi-armed chromosomes resulted from two centric fusions involving the equivalent of cattle chromosomes 1 and 29, and 2 and 28, respectively. Cross-species fluorescence in-situ hybridization (FISH) with B. taurus whole chromosome paints and satellite DNA I probes was used to identify the chromosomes involved in the translocations, and their orientation. We suggest that Robertsonian translocations (1;29) and (2;28) have been fixed in the common ancestor of Cambodian banteng as a consequence of hybridization with the kouprey (Bos sauveli) during the Pleistocene epoch.

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Abstract. Atherosclerosis is a common disease in pet birds, particularly in psittacines, and is frequently found when performing postmortem examinations on adult and old dogs, in which it is mainly associated with endocrine diseases, such as hypothyroidism and diabetes mellitus. However, atherosclerosis is poorly documented in reptiles and consequently poorly understood. In the current case report, atherosclerosis and pericardial effusion were diagnosed in a 2-year-old male central bearded dragon (Pogona vitticeps) based on ultrasound visualization, necropsy, and histologic examination.Key words: Atherosclerosis; bearded dragons; echocardiography; exotic pets; lizards; reptiles.A 0.4 kg, 2-year-old, male, captive-born central bearded dragon (Pogona vitticeps) was presented with a 3-week history of anorexia, extreme lethargy, and postural abnormality. The animal was purchased in a pet store and lived in isolation in a terrarium. Upon questioning, the owner described the general husbandry as adequate and appropriate in terms of ultraviolet B exposure, photoperiod, humidity, substrate, and temperature gradients. However, the animal's diet was unbalanced, consisting essentially of house crickets (Acheta domesticus), yellow mealworms (Tenebrio molitor), kingworm beetles (Zophobas morio), and greater wax moth larvae (Galleria mellonella). Vegetables, necessary for the omnivorous requirements of this species, were rarely if ever given.Physical examination revealed scoliosis, poor body condition, and lethargy. No additional abnormal findings were observed on physical examination. Auscultation revealed a normal heart rate (60 beats/min) and a regular cardiac rhythm. 25No biochemical abnormalities were noted except mild hyperglycemia and hypercholesterolemia (Table 1).5 Cardiomegaly was observed on survey thoracic radiographs (Fig. 1). 21 No lytic or proliferative osseous lesions were observed in association with the scoliosis. A 2-dimensional echocardiographic examination was performed in ventrodorsal recumbency using a ventral approach (Hochleitner C, Hochleitner M: 2004, Ultrasound in reptiles. Proceedings of the Association of Reptilian Amphibian Veterinarians, pp. 41-44. Naples, FL). a,3,8,15,17,19,20 The apical, transventricular, and subarterial short-axis sections of the heart revealed pericardial effusion, normal myocardium, and a 3 mm 3 4 mm mass located close to the aortic arches and the pulmonary trunk, surrounded by anechoic liquid (Fig. 2). A long-axis transarterial section revealed normal atrioventricular junctions.

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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.