Comparison of growth and nutritional status of juvenile Komodo monitors (Varanus komodoensis) maintained on rodent or poultry‐based diets

Nutrition and growth data were collected on six juvenile Komodo monitors (Varanus komodoensis) over 20 months. The animals were captive‐bred from two separate clutches, laid 6 months apart. Three animals were fed a rodent diet, and the other three were fed a poultry‐based diet. The animals were all weighed and measured weekly. Blood samples were collected monthly. Blood samples were analyzed for sodium (Na), potassium (K), calcium (Ca), phosphorus (P), magnesium (Mg), 25‐OH‐D, and cholesterol. Significant differences (P<0.05) were observed in dry matter intake (DMI) (1.12 vs. 0.90 %BW) and gross energy intake (GEI) (182.3 vs. 143.0 kcal GE/d), between rodent and poultry‐based diets, respectively. However, there were no differences in growth (average daily gain=6.13 vs. 6.33 g BW/d) between the two dietary treatments. Blood Na, K, Ca, P, Mg, and 25‐OH‐D concentrations were similar across treatments, while cholesterol levels were higher in the animals maintained on the rodent‐based diet. Zoo Biol 23:239–252, 2004. © 2004 Wiley‐Liss, Inc.     

Development of a multiplex PCR assay for fine-scale population genetic analysis of the Komodo monitor Varanus komodoensis based on 18 polymorphic microsatellite loci

Multiplex PCR assays for the coamplification of microsatellite loci allow rapid and cost-effective genetic analyses and the production of efficient screening protocols for international breeding programs. We constructed a partial genomic library enriched for di-nucleotide repeats and characterized 14 new microsatellite loci for the Komodo monitor (or Komodo dragon, Varanus komodoensis). Using these novel microsatellites and four previously described loci, we developed multiplex PCR assays that may be loaded on a genetic analyser in three separate panels. We tested the novel set of microsatellites for polymorphism using 69 individuals from three island populations and evaluated the resolving power of the entire panel of 18 loci by conducting (i) a preliminary assignment test to determine population(s) of origin and (ii) a parentage analysis for 43 captive Komodo monitors. This panel of polymorphic loci proved useful for both purposes and thus can be exploited for fine-scale population genetic analyses and as part of international captive breeding programs directed at maintaining genetically viable ex situ populations and reintroductions.     

Body temperature and thermoregulation of Komodo dragons in the field

Komodo dragons from hatchlings (≈0.1 kg) to adults (≤80 kg) express the full magnitude of varanid species size distributions. We found that all size groups of dragons regulated a similar preferred body temperature by exploiting a heterogeneous thermal environment within savanna, forest and mangrove habitats. All dragons studied, regardless of size, were able to regulate a daytime active body temperature within the range 34–35.6 °C for 5.1–5.6 h/day. The index of effectiveness of thermoregulation (a numerical rating of thermoregulatory activity) was not different among size groups of dragons. However, the index of closeness of thermoregulation, which rates the variability of body temperature, suggests a greater precision for regulating a preferred body temperature for medium compared to small and large dragons. Reference copper cylinders simulating small, medium and large Komodo dragons heated and cooled at the same rate, whereas actual dragons of all size groups heated faster than they cooled. Larger dragons heated and cooled more slowly than smaller ones. The mean operative environmental temperatures of copper cylinders representing medium sized dragons were 42.5, 32.0 and 29.4° C for savannah, forest and mangrove habitats, respectively. The index for average thermal quality of a habitat as measured by the absolute difference between operative environmental temperature and the dragon’s thermal range suggests the forest habitat offers the highest thermal quality to dragons and the savannah the lowest. The percent of total daytime that the operative environmental temperature was within the central 50% of the body temperatures selected by dragons in a thermal gradient (Phillips, 1984) was 45%, 15%, and 9% for forest, mangrove and savannah, respectively. Forest habitat offers the most suitable thermal environment and provides the greatest number of hours with conditions falling within the dragon’s thermal activity zone.     

Characterization of ten microsatellite marker loci in the Komodo Monitor (<Emphasis Type="Italic">Varanus komodoensis</Emphasis>)

The Komodo monitor (Varanus komodoensis) is a classic example of a species that has been fragmented into small isolated populations over a limited range. This species, classified as endangered under Appendix I of the Convention on the International Trade of Endangered Species. We describe 10 novel species-specific microsatellite loci characterized in representatives from three of the endemic island populations. One locus, 12HDZ820 appears to be fixed in one population at an allele size not found in the other two. This microsatellite suite should be helpful in augmenting the marker selection currently available for Komodo Monitor population studies.     

The effects of biting and pulling on the forces generated during feeding in the Komodo dragon (Varanus komodoensis)

In addition to biting, it has been speculated that the forces resulting from pulling on food items may also contribute to feeding success in carnivorous vertebrates. We present an in vivo analysis of both bite and pulling forces in Varanus komodoensis, the Komodo dragon, to determine how they contribute to feeding behavior. Observations of cranial modeling and behavior suggest that V. komodoensis feeds using bite force supplemented by pulling in the caudal/ventrocaudal direction. We tested these observations using force gauges/transducers to measure biting and pulling forces. Maximum bite force correlates with both body mass and total body length, likely due to increased muscle mass. Individuals showed consistent behaviors when biting, including the typical medial-caudal head rotation. Pull force correlates best with total body length, longer limbs and larger postcranial motions. None of these forces correlated well with head dimensions. When pulling, V. komodoensis use neck and limb movements that are associated with increased caudal and ventral oriented force. Measured bite force in Varanus komodoensis is similar to several previous estimations based on 3D models, but is low for its body mass relative to other vertebrates. Pull force, especially in the ventrocaudal direction, would allow individuals to hunt and deflesh with high success without the need of strong jaw adductors. In future studies, pull forces need to be considered for a complete understanding of vertebrate carnivore feeding dynamics.     

Response of hatchling Komodo Dragons (Varanus komodoensis) at Denver Zoo to visual and chemical cues arising from prey

Five hatchling Komodo Dragons (Varanus komodoensis) at Denver Zoo were observed in two experiments that studied the effects of visual and chemical cues arising from prey. Rate of tongue flicking was recorded in Experiment 1, and amount of time the lizards spent interacting with stimuli was recorded in Experiment 2. Our hypothesis was that young V. komodoensis would be more dependent upon vision than chemoreception, especially when dealing with live, moving, prey. Although visual cues, including prey motion, had a significant effect, chemical cues had a far stronger effect. Implications of this falsification of our initial hypothesis are discussed. Zoo Biol 28:29–34, 2009. © 2008 Wiley-Liss, Inc.     

Oldest known Varanus (Squamata: Varanidae) from the Upper Eocene and Lower Oligocene of Egypt: support for an African origin of the genus

Abstract: A large collection of lizard vertebrae from northern Africa represents the oldest unambiguous occurrence of the genus Varanus. The fossils come from late Eocene and early Oligocene freshwater deposits of the Fayum, Egypt, an area noted for many significant primate finds. The recovery and identification of this material indicate that the genus Varanus arose in Africa, before dispersing to Australia and Asia. This dispersal occurred prior to the early to mid‐Miocene, by which time fossil Varanus are known from Australia and Eurasia. Although the dispersal route remains unknown, the lizard material reported here supports the hypothesis that a corridor existed allowing freshwater and terrestrial organisms to cross from Africa to Asia.     

Activity areas and daily movements of an arboreal monitor lizard,Varanus tristis (Squamata: Varanidae) during the breeding season

During the breeding season, in the western Great Victoria Desert, Western Australia, male Varanus tristis move greater daily distances (186.5 m) than females (99.7 m) and have larger activity areas (40.3 ha vs 3.7 ha). V. tristis retreat predominantly to live and dead upright Eucalyptus gongylocarpa (marble gum) trees that have hollows in their trunks and limbs. There is no observable difference between males and females in their preferred habitat, but females are found more frequently in a lesser number of preferred retreats during the breeding season.     

Direct evidence for the localization of the steroid-binding site of the plasma sex steroid-binding protein (SBP or SHBG) at the interface between the subunits.

Complete dissociation of dimeric plasma sex steroid-binding protein (SBP or SHBG) was obtained in 6 M urea at 10 degrees C. Removal of urea resulted in the refolding of monomers, followed by reformation of dimeric SBP, which migrates with the same mobility as the native protein. Dimerization does not require Ca+2 or steroid. Renatured monomers yield dimers with dissociation constants for 5 alpha-dihydrotesterone (DHT) and 17 beta-estradiol (E2) indistinguishable from those of native human SBP. This phenomenon was also demonstrated by mixing human and rabbit SBPs that, upon renaturation, form a hybrid dimer composed of one human subunit and one rabbit subunit. The hybrid binds both DHT and E2 in contrast to rSBP, which only binds the androgen. Therefore, we conclude that (1) docking of the two subunits creates an asymmetric steroid-binding site located at the interface between the subunits, and (2) only one face of the dimer defines the specificity for binding E2 by encompassing portion of a structural motif that recognizes the flat ring A of E2. The remaining portion, which recognizes the saturated ring A of DHT, is shared by both faces of the dimer. Because native monomers do not exist alone, the often-asked question of whether the SBP monomer binds steroid can be considered meaningless; steroid-binding activity is expressed only in the dimeric state. Finally, formation of the hybrid indicates that SBP dimerization represents a conserved event during the molecular evolution of SBP, suggesting that the structural elements responsible for dimerization will be homologous in SBPs from other species.     

Comparative insights using the molecular homology model of BDNF (Brain derived neurotrophic factor) of Varanus komodoensis and the known NGF (Nerve growth factor) structure of Naja atra

BDNF (Brain derived neurotrophic factor) is a secretion protein and a member of the neurotrophin family of growth factors. Structural and functional characterization of BDNF Varanus komodoensis is of interest while its structure remains unknown. Thus, a homology molecular model of BDNF was constructed for gleaning possible structural insights. The model was compared with the structure of the homologous NGF (Nerve growth factor, another member of neuro-trophin family) from Naja atra. Comparative structural analysis of the models showed structural similarities with their predicted cavities for the interpretation of potential functional analogy.     

Masculinization of the gynogenetic juvenile ship sturgeon (Acipenser nudiventris Lovetsky, 1828) using 17α‐methyl testosterone

In sturgeons, the induction of gynogenesis and sex reversal could be important for potential production of neomale sturgeon and all‐female progeny for caviar production. The aim of this study was sex reversal of ship sturgeon (Acipenser nudiventris Lovetsky, 1828) gynogen into male sex. Five‐month‐old gynogens were sex reversed into male by including 17α‐methyl testosterone in their food for 7 months. Three treatments were considered as follows: (a) without treated (gynogen control), (b) 10 mg MT/kg diet, and (c) 50 mg MT/kg diet. All treatments (60 individuals) were sampled both the 30 and 36 months old and their sex was determined using classical histology method of gonad. The sex ratio of the progenies in the gynogen control were 73.3% female and 26.7% male. In treatment of 10 mg MT/kg feed, 18 specimens were studied that half of them (50%) showed pseudo‐testicular structure in the female gonad. That is 50% of the specimens were intersex, 27.7% were male and 22.3% were female. All of the fish fed by 50 mg MT/kg feed had been sex reversed to male. Sexual maturation of these fish had been recognized in stage III at 36 months old. In conclusion, 50 mg MT/kg feed found as effective dose for successful sex reversal in gynogenetic ship sturgeon.     

Rapid bioconcentration of steroids in the plasma of three-spined stickleback Gasterosteus aculeatus exposed to waterborne testosterone and 17β-oestradiol

The relationship over time between the concentrations of two steroids, singly and in combination, in a static exposure system and in the blood of three-spined stickleback Gasterosteus aculeatus , held within the exposure system was investigated. Groups of three-spined stickleback were exposed (nominally) to either 1000 ng l⁻¹ 17β-oestradiol (E2), testosterone (T) or E2 and T in combination at the same concentrations for 6 days. Both water and fish were sampled at intervals and steroid concentrations in both compartments were determined. The plasma steroid time profile revealed a rapid bioconcentration within the first 6 h of exposure. The plasma steroid levels attained at this time point (20–90 ng ml⁻¹) were up to 50-fold (E2) and 200-fold (T) greater than the actual levels of steroid measured in the exposure water, while levels in the blood of control fish did not exceed 4 ng ml⁻¹. The substantial elevation of plasma steroid levels relative to the concentrations of steroid to which the fish were exposed in the ambient water gives scope for delivery of the steroids to target endocrine tissues at levels far in excess of what might be predicted on the basis of passive branchial uptake alone. These results are discussed in relation to endocrine disruption, and in particular the occurrence of effects in fish exposed to levels of endocrine active substances that are seemingly physiologically irrelevant.     

Assessing the development and treatment of rheumatoid arthritis using multiparametric photoacoustic and ultrasound imaging

Rheumatoid arthritis (RA), characterized by polyarthritis, is a chronic, systemic and inflammatory autoimmune disease. In this study, we developed a dual‐modality multiparametric photoacoustic and ultrasound imaging technique, and successfully derived multiple parameters such as relative concentration of total hemoglobin (C_HbT), ratio of angiogenesis, joint size and area of synovia to assess the development and treatment of RA. We established a model of adjuvant arthritis using a total number of 15 rats and randomly divided them into three groups: (a) targeted group in which the rats received targeted antirheumatic drugs; (b) nontargeted group in which the rats were treated with nontargeted antirheumatic drugs; (c) control group. We longitudinally monitored the joints of the rats in all three groups for up to 20 days and carried out quantitative analysis to evaluate the development and treatment of RA based on the derived parameters. The results suggest that the proposed dual‐modality imaging technique is able to assess the effectiveness of the RA treatment using quantitative hemodynamic and morphological parameters. To show the clinical feasibility of this technique, we performed in vivo joint studies of health volunteers to visualize both structures and inside hemodynamics of the distal interphalangeal joint.     

Assessment of reproductive status and ovulation in female brown kiwi (Apteryx mantelli) using fecal steroids and ovarian follicle size

Despite being listed as endangered on the IUCN (World Conservation Union) red list [BirdLife International 2005], and intense conservation efforts on its behalf, little is known about the reproductive physiology of the brown kiwi (Apteryx mantelli). This study therefore was undertaken to describe ovarian function in brown kiwi using noninvasive methods that can be utilized in the field. This study describes a simple method for extraction and detection of steroid metabolites in brown kiwi feces by enzyme‐linked immunosorbent assay (ELISA). Average fecal steroid hormone metabolite concentrations were derived from 10 egg‐lay cycles in 2 hens. Testosterone began to increase between 23 and 18 days before oviposition (?23d to ?18d) and remained elevated until just before oviposition. Estradiol rose from ?28d to ?13d and remained elevated until 12 days after oviposition. Progesterone exhibited an increase of short duration from ?8d to +7d with a peak at ?3d. Ovarian follicle growth rate was determined by serial ultrasound measurements of follicles in three habituated female kiwi. Follicle growth rate was described by the formula y=132.54e^0.0569x (y=follicle diameter, x=days before oviposition). Follicles ranged in size from 10 to 76 mm. Day of ovulation was estimated using egg yolk size, follicle growth curve, and day of oviposition. This yielded an ovulation‐oviposition cycle length of 7–10 days, significantly shorter than the only other estimate of 16–17 days derived using body weights of a single kiwi hen. The correlation of fecal steroid hormone concentrations with follicle growth provides new insight into the reproductive physiology of the female brown kiwi. Zoo Biol 0:1–10, 2005. © 2005 Wiley‐Liss, Inc.     

Is tissue harmonic ultrasound imaging (THI) of the prostatic urethra and rectum superior to brightness (B) mode imaging? An observer study

Quality ultrasound images are an essential part of prostate brachytherapy procedure. The authors have previously reported that tissue harmonic ultrasound images (THI) are superior to brightness (B) mode for the prostate. The objective of the current study was to compare both imaging modes for visualization of the prostatic urethra and rectum.B and THI mode transrectal ultrasound images were acquired for ten patients. The prostatic urethra and rectal wall were contoured by a radiation oncologist (RO) and five observers on randomly presented images. The contours on one patient were repeated four additional times by four observers. All the images were qualitatively scored using a five-level Likert scale.The values of the Pearson product-moment correlation coefficients showed that the observers were in close agreement with the RO. Two sample paired student t-test showed that the rectum volumes with THI were significantly smaller than B-mode, but no significant difference for urethra. Two-factor analysis of variances showed significant observer variability in defining the rectum and urethra in both imaging modes. Observer consistency of the rectum volumes, estimated by standard deviations as percentages of means was significantly improved for THI. The Likert scale based qualitative assessment supported quantitative observations.The significant improvement in image quality of the prostate (reported previously) and rectum with THI may offer better-quality treatment plans for prostate brachytherapy and potential improvement in local control.     

睾酮对去睾丸家兔骨密度及血清钙磷的影响

目的:观察去睾丸和睾酮补充对雄兔骨密度和血清钙、镁、磷的影响.方法:周龄相同的雄性新西兰白兔随机分成对照组、去睾丸组和睾酮补充组(去睾丸后肌注十一酸睾酮).同等条件下饲养20周后测量各组兔全身骨密度、腰椎骨密度、股骨颈骨密度,并检测血清总睾酮(TT)、雌二醇(E2),脱氢表雄酮(DHEA)水平以及血清钙(Ca2 )、游离钙([Ca2 ]i)镁(Mg2 )、磷(P)和碱性磷酸酶(AKP)浓度.结果:去睾丸组血清TT水平明显下降(P<0.01),睾酮补充组血清TT水平升高接近对照组(P>0.05).去睾丸组血清E2和E2/TT比明显高于对照组(P<0.01),睾酮补充组血清E2和E2/TT下降,接近对照组水平(P均>0.05).与对照组相比,去睾丸组血清Ca2 、[Ca2 ]i、Mg2 以及AKP浓度明显升高(P均<0.01),睾酮补充组血清Ca2 、[Ca2 ]i、Mg2 以及AKP浓度较去睾丸组低,接近对照组水平(P>0.05).股骨颈骨密度在去睾丸组明显低于对照组和睾酮补充组(P<0.01),而后两组无差别(P>0.05).结论:去睾丸后雄兔血清TT明显下降,E2和E2/TT比以及Ca2 、[Ca2 ]i、Mg2 和AKP浓度明显升高,骨密度显著下降,睾酮补充使上述异常明显改善.     

Strain imaging of the lateral collateral ligament using high frequency and conventional ultrasound imaging: An ex-vivo comparison

Recent first attempts of in situ ultrasound strain imaging in collateral ligaments encountered a number of challenges and illustrated a clear need for additional studies and more thorough validation of the available strain imaging methods. Therefore, in this study we experimentally validated ultrasound strain measurements of ex vivo human lateral collateral ligaments in an axial loading condition. Moreover, the use of high frequency ultrasound (>20 MHz) for strain measurement was explored and its performance compared to conventional ultrasound. The ligaments were stretched up to 5% strain and ultrasound measurements were compared to surface strain measurements from optical digital image correlation (DIC) techniques. The results show good correlations between ultrasound based and DIC based strain measures with R² values of 0.71 and 0.93 for high frequency and conventional ultrasound, subsequently. The performance of conventional ultrasound was significantly higher compared to high frequency ultrasound strain imaging, as the high frequency based method seemed more prone to errors. This study demonstrates that ultrasound strain imaging is feasible in ex vivo lateral collateral ligaments, which are relatively small structures. Additional studies should be designed for a more informed assessment of optimal in vivo strain measurements in collateral knee ligaments.     

Early sex identification of 18‐month cultured beluga sturgeon (Huso huso) using ultrasonography,small surgery and plasma steroid hormones

Since sturgeons do not show clear sexual dimorphism particularly when are small in size, attempts were made to determine the best methods to identify early sex in farmed beluga sturgeon (Huso huso). The present study describes the ultrasonography, small surgery and plasma steroid hormone methods to determine gender at 18‐month fish, which no research has been conducted yet into the fish at such small ages. Twenty one cultured beluga sturgeon's gonad were imaged using an ultrasonograph unit with a 9–13 MHz linear transducer. Overall accuracy of sex determination using ultrasonography was 80.95%. Plasma testosterone (T) levels were significantly higher in males than in females whereas 17α,20βOH‐P levels were significantly higher in females than in males. Testosterone (T) and 17α,20βOH‐P were not correlated with morphometric parameters (TL, SL, W, CF) in 18‐month beluga sturgeon. Results of this study indicated that sex could be identified by each of ultrasonography, small surgery and analysis of blood plasma in such a small size (18‐month). Although direct observation was more efficient than the other methods, ultrasonography was the simplest and cost‐effective tool in sturgeon's sex determination compared to other methods, and the least invasive.