Golden Hamsters Mesocricetus Auratus Research Articles

Renal Dysplasia in a Free-Living Giant Anteater Cub (Myrmecophaga tridactyla) - Ultrasonographic and Tomographic Aspects

Background: Renal dysplasia is a congenital disorder that occurs during differentiation of the renal parenchyma or as a consequence of a functional and/or structural obstruction of the lower urinary tract. In wild animals, this pathology has been reported in cynomolgus monkeys (Macaca fascicularis), golden hamsters (Mesocricetus auratus) and African elephants (Loxodanta africana). However, there are no reports of the disease in the giant anteater (Myrmecophaga tridactyla). Thus, this paper describes a case of renal dysplasia in a free-living giant anteater cub, which was sent to the wild animal clinic of the Federal University of Mato Grosso (UFMT) in Cuiabá, MT, Brazil. Case: The rescued animal had a good body condition score and clinical parameters within the normal range for the species. After a routine clinical evaluation, the anteater cub was subjected to radiography and ultrasound tests. Blood tests, serum tests for hepatic and renal profiles, urinalysis, urinary protein creatinine ratio, and chest X-rays did not reveal significant changes. However, the abdominal ultrasound examination revealed a volumetric loss of about 1.17 cm in length in the left kidney, and a renal length to aortic artery diameter ratio of approximately 2.8. This kidney showed irregular contours, loss of corticomedullary demarcation, with preserved echogenicity and cortical echotexture. The right kidney showed the standard size of the species, with a length of approximately 3.08 cm. In view of the suspicion of renal dysplasia, a contrast-enhanced CT scan was performed in order to assess the dynamics of uptake and excretion of the contrast medium in the affected kidney and in the ipsilateral collecting system. An examination of the tomographic images indicated that the volume of the left kidney was reduced, isodense in relation to the right kidney, with discrete and homogeneous uptake in all phases after administration of the contrast medium, no occurrence of nephrogram and pyelogram phases, or any detection of contrast in the corresponding ureter.Discussion: Giant anteaters (Myrmecophaga tridactyla) are animals classified as a species vulnerable to extinction. Today, most research involving this species focuses on its ecology, behavior, diet, morphology and parasitology, but little is known about the imaging aspects of the species or about congenital changes such as renal dysplasia. Although the definitive diagnosis of this pathology depends on a histopathological examination, the same diagnosis can be made with a wide margin of safety by assessing the epidemiological aspects and the dynamics of renal uptake of the contrast medium through computed tomography. In this analysis, both vascularization and renal filtration capacity can be assessed. Thus, based on CT imaging, it was concluded that this was a case of renal dysplasia, since the left kidney showed a discrete homogeneous uptake stable in both the arterial and venous phases, without producing any accumulation of contrast medium in the pelvic region or the collecting system, proving to be completely nonfunctional. These findings differ from cases of renal hypoplasia, which, although they reduce renal volume, do not cause structural changes in the renal parenchyma or disturbances in the filtration dynamics of contrast media. They also differ from cases of acquired chronic nephropathy, since, albeit associated with reduced renal volume and changes in renal filtration dynamics, they produce different parenchymal ultrasound changes that usually occur in elderly animals and generally produce bilateral lesions.

Melatonin ameliorates Bisphenol S induced testicular damages by modulating Nrf-2/HO-1 and SIRT-1/FOXO-1 expressions.

BPS has detrimental effects on human reproductive health and emerged as an environmental contaminant for global health concern. This study deals with the adverse impact of BPS exposure on testicular oxidative stress, inflammation and apoptosis in adult male golden hamster, Mesocricetus auratus and its amelioration by melatonin. BPS (75 mg/kg BW/day) exposure caused testicular impairment as evident by histological degenerative changes, declined sperm quality (viability and motility), serum levels of testosterone and melatonin with a concomitant decrease in testicular androgen receptor (AR) and melatonin receptor (MT1) expression. The BPS exposure caused marked increase in testicular oxidative load, inflammation (NF-kB/COX-2) and apoptosis (caspase-3). Melatonin (10 mg/kg BW/alternate day) pretreatment to BPS exposed hamsters resumed normal testicular histoarchitecture, sperm quality and decreased testicular oxidative load as evident by enhanced antioxidant enzymes (SOD and catalase) activities and decreased lipid peroxidation (LPO) level. Further, melatonin also stimulated the testicular antioxidant proteins Nrf-2/HO-1, SIRT-1/FOXO-1 and reduced inflammatory proteins NF-kB/COX-2 expression to counteract BPS induced testicular damages. Melatonin administration to the BPS treated hamsters resulted in increased testicular cell proliferation (PCNA), survival (Bcl-2), gap junction (connexin-43) and decreased apoptosis (caspase-3). In conclusion, our study documented the detrimental effects of BPS on testes that compromises male fertility. Further, melatonin was found as a potent molecule that rescued the BPS induced testicular damages in male golden hamster Mesocricetus auratus.

Influence of phytomelatonin on immune cell function in male golden hamsters

BACKGROUND: An assortment of plant animal groups incorporates phytomelatonin, shows the similar pattern as in animals recommending its capacity can be closely resemble animals as in plants. AIMS AND OBJECTIVES: An in vivo research work needed to explore the impact of dietary phytomelatonin, i.e., the cabbage and carrot, on immune cell functions in a male rodent golden hamster (Mesocricetus auratus). MATERIALS AND METHODS: In this study, we examined the general immune response (spleen weight, total leukocyte count, and % lymphocyte), delayed type hypersensitivity (DTH) response, the blastogenic response of peripheral blood mononuclear cell (PBMC), splenocytes, and bone marrow mononuclear cell proliferation in terms of granulocyte macrophage colony forming unit (GM CFU) count, as an indicator of bone marrow macrophages. RESULTS: An increased circulatory melatonin level due to melatonin supplemented diet enhanced the total leukocyte count, % lymphocyte count, a proliferation of splenocytes, PBMCs, GM CFU count, % DTH response, and serum cytokine (interleukin 2 and interferon γ) production. CONCLUSION: A correlation study recommended that incited serum melatonin is emphatically corresponded with the improvement of the safe status of hamsters. In this way, our information infers that dietary melatonin may impact resistance on account of its high selectivity and sensitivity. Thus, it could be suggested that the dietary phytomelatonin might be one of the strong restorative procedures to enhance the immune responses for better well being of a person at its any age of life.

Types of sterilization in feed containing different lipidic sources for golden hamster (Mesocricetus auratus)

Abstract The Golden hamster has been gaining significance as a new experimental biomodel, finding use as a reliable diagnostic tool in biomedical research and for zoonosis. Authentic data in terms of digestibility, interactions among raw materials and essential nutrients, besides the influence exerted by various sterilization processes on animal behavior remain unclear. We aimed to assess the influence of sterilization, via autoclaving and irradiation, of pellet feeds prepared using salmon or linseed oil on the digestibility and plasma biochemical parameters in Golden hamsters. Randomized evaluations were conducted on 36 adult male Golden hamsters (Mesocricetus auratus), distributed in six treatments and six replications, namely: common salmon oil; radiated salmon; autoclaved salmon; common linseed oil; radiated linseed and autoclaved linseed. A remarkable effect of the sterilization was evident on the digestibility and protein solubility of the feed, which was lower for autoclaved diets. There was also a significant effect on blood parameters. Animals fed diets containing linseed oil showed lower blood glucose compared to the others. Thus, the inference reached was that while salmon and linseed oil can be used in laboratory hamster feeds, autoclaving disturbs the nutritional quality of the rations.

Aggression and plasma testosterone in male golden hamsters (Mesocricetus auratus) in response to encounters with receptive vs. nonreceptive females

Exposure to sexual stimuli can lead to increased aggression in male mammals, but it is unclear whether the aggression is related to the receptiveness of the females. Interactions with receptive females elicit testosterone (T) pulses that are important for sexual behaviors. We investigated the effects of male–female interactions on subsequent aggressive behaviors and T responses in the golden hamster (Mesocricetus auratus (Waterhouse, 1839)). Three groups (n = 18, 17, and 18) of males were exposed to receptive females, nonreceptive females, and blank (control), respectively. Then, we randomly chose eight animals from each group and measured their aggression toward an unfamiliar male conspecific; the remaining 29 males were used for a T assay (to avoid effects of aggression on T levels). The results show that interactions with females led to significantly higher male aggression and T levels than were found in control males. The increased aggression was not related to the receptiveness of the females, but receptive females elicited higher levels of T in males than nonreceptive females. Our findings suggest that the elevated aggression following the sexual encounter may serve to defend the female, by enhancing the ability of males to exclude other males from the vicinity of females, whereas the post-encounter T release may serve to assist mating behaviors and reproductive success.

Interferon response in a hamster model of arenavirus hemorrhagic disease

A difficulty in studying hemorrhagic arenavirus pathogenesis is a lack of animal models that recapitulate human disease and which can be manipulated at BSL-3 or lower. Pirital virus (PIRV), a South American arenavirus hosted by Alston’s cotton rats ( Sigmodon alstoni ), has not been shown to cause disease in humans and is considered a BSL-3 agent. Infection of Syrian golden hamsters ( Mesocricetus auratus ) causes a disease that shares many features of the South American hemorrhagic fevers and Lassa fever. Significantly, neurological manifestations occur, a feature commonly found in Argentine hemorrhagic fever and which is absent in most other models of arenavirus disease. We examined the pathogenesis of PIRV infection by clinical and molecular methods, with a focus on gene expression of the antiviral type I interferon response using RNA-Seq. More than 3,000 genes were differentially expressed in the livers of infected hamsters, of which 86 are involved with antiviral responses. Several of these genes participate in apoptosis and autophagy, which may suggest a mechanism of pathogenesis observed in damaged livers.

<i>Opisthorchis felineus</i> Infection and Harmful Metals Bio-Concentration: A Pilot Study in Hamster Model

Nowadays, the question about the negative impacts of liver fluke on the host organism and mechanisms of this damage is open. The bio-concentration of some heavy and toxic metals in tissue of adult forms of Opisthorchis felineus and its accumulation in liver tissue and cardiac muscle in the Syrian Golden Hamster (Mesocricetus auratus) model was analyzed. It is outlined, that Opisthorchis felineus infection leads to accumulating aluminum in a liver tissue of the host. It was also found, that adult fluke bio-concentrates iron and aluminum in their tissue. The shortage of such essential elements as Mn, Zn and Сu in infected organism is discussed.

Removal of the vomeronasal organ impairs predator odor detection in female golden hamsters

The main and accessory olfactory systems of mammals are involved in the detection of predator odor; however, the relative importance assigned to each varies between studies. We examined the behavioral responses of vomeronasal organ removed (VNOx) and sham operated (VNOi) female golden hamsters (Mesocricetus auratus) to urine odor from a predator, the ferret (Mustela putorius furo). We quantified the duration and frequency of the defensive behaviors vigilant rearing and concealment, and the neutral behaviors grooming and investigation, in female golden hamsters in a visible burrow system. We found that VNOx females exposed to predator urine odor spent significantly less time in concealment and more time rearing than VNOi females. Further experiments in which females were exposed to formaldehyde odor showed that their behavioral responses to ferret odor differed from those to formaldehyde odor. This shows that the female hamsters’ behavioral responses are not adverse reactions to noxious odors, but typical reactions to predators. Golden hamsters have been laboratory-reared for over 80 years, but defensive behavior in females appears to be innate and can be impaired by surgical removal of the vomeronasal organ. Therefore, the accessory olfactory system, via the vomeronasal organ, plays a role in the detection of predator odor by golden hamsters, even though it has not been found to function in conspecific odor discrimination.

Evolution conservatively of SCAR DNA localization in genome isochores of warm-blooded vertebrates

In meiotic prophase I, chromatin fibrils attached to the lateral elements of the synaptonemal complexes form loops. Synaptonemal complex associated regions of DNA (SCARs DNA) are a family of genomic DNA sequences tightly associated with the synaptonemal complex; they are located at the chromatin loop basements. Isochore compositional fractions of the human and chicken genomes were used as 32P labeled probes for hybridization with SCAR DNA isolated previously from the spermatocyte nuclei of the golden hamster Mesocricetus auratus. Nucleotide sequences similar to the golden hamster’s SCAR DNA were found in human and chicken genome isochores. The localization of SCAR DNA in isochore compartments of the examined genomes was established to be evolutionary conservative.

Allergy to hamster - 4 case reports

Background Hamsters are increasingly popular as domestic pets. Different species can be found in the domestic setting: the Syrian (golden) hamster (Mesocricetus auratus), the European hamster (Cricetus cricetus), the Siberian hamster (Phodopus sungorus) and the Rhoborovski hamster (Phodopus roborovskii). Several cases of asthma upon contact with hamsters and anaphylaxis following hamster bites have been described, but the allergen(s) responsible are either unidentified or poorly characterized. In the Syrian hamster, salivary lipocalins were found to be specifically expressed in male submandibular glands. MSP (male specific submandibular salivary gland protein) is detectable in saliva as two major forms of 20.5 and 24 kDa. The objectives of the present study were to determine if MSP is an allergen, to analyse IgE reactive proteins in different hamster fur extracts and to determine patient reactivity to different extracts.

Vitellogenesis of the digenean Plagiorchis elegans (Rudolphi, 1802) (Plagiorchioidea, Plagiorchiidae)

The ultrastructural organization of vitellogenesis of Plagiorchis elegans (Rudolphi, 1802), experimentally obtained from the golden hamster Mesocricetus auratus (Linnaeus, 1758), is described using transmission electron microscopy. This study is the first ultrastructural study of vitellogenesis in a member of the superfamily Plagiorchioidea. The four stages usually observed during vitellogenesis are described: stage I, cytoplasm of the vitellocytes mainly filled with ribosomes and few mitochondria; stage II, beginning of the synthetic activity; stage III, active synthesis of the shell globule clusters; stage IV, vitellocytes are filled with shell globule clusters and contain several lipid droplets, and glycogen granules are grouped around clusters and droplets. Vitellogenesis in P. elegans is compared with that of other Digenea. The differences among P. elegans and previously studied digeneans include, but are not limited to the occurrence of dense coiled endoplasmic reticulum saccules and the concentration of glycogen in the mesenchyme, which may be considered as a fifth stage of maturation of the vitelline glands. This peculiarity was not observed in all trematodes, which clearly indicates differences in the vitellogenesis in various digenean lineages at different stages of maturation of their vitelline cells.

Persistence of experimental Rocio virus infection in the golden hamster (Mesocricetus auratus)

Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR). The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC). ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection.

Uterotrophic response of immature golden hamsters (Mesocricetus auratus) to model estrogen agonists and antagonists

Uterotrophic response of immature golden hamsters (Mesocricetus auratus) to model estrogen agonists and antagonists

Vacuolation and mineralisation as dominant age-related findings in hamster brains

Syrian golden hamsters (Mesocricetus auratus) are laboratory animals increasingly used for research and toxicological studies. Despite the need for an adequate knowledge of spontaneously occurring lesions, studies investigating the background pathology of different organ systems in hamsters are lacking. The aim of this study was to investigate the occurrence of spontaneous, age-dependent lesions in the central nervous system of this species. Multiple brain and spinal cord transverse sections of 520 hamsters of 1, 3, 6, 12, and 24 months of age were investigated using histology and immunohistochemistry. Vacuolation of grey matter neuropil and mineralisation especially in the brain stem were the most prominent findings. They gradually increased in severity and frequency with age. Vacuolation and mineralisation affected approximately 100% and 50% of 24-month-old hamsters, respectively. In addition, pigment deposition and mast cell infiltration were commonly detected. Whether vacuolation and mineralisation represent an incidental finding or are related to a cognitive dysfunction syndrome remains to be determined.

Roborovskin, a Lipocalin in the Urine of the Roborovski Hamster, Phodopus roborovskii

Many rodents are now known to exhibit an obligate proteinuria that delivers urine-mediated chemosignals. In this paper, we explore the urinary proteins of the Roborovski hamster (Phodopus roborovskii). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of urine from individual male and female Roborovski hamsters revealed 2 proteins, with approximate masses of 6 and 17 kDa, the expression pattern of which showed little variation between individuals or between sexes. Peptide mass fingerprints obtained from these 2 proteins revealed a number of features: 1) the proteins of a given mass were the same in all individuals regardless of sex, 2) the 6 kDa protein was not a fragment of the 21 kDa protein, and 3) neither protein was a fragment of a larger, conserved protein such as serum albumin. Electrospray mass spectrometry of purified protein preparations established the mass of the larger protein as invariant, at 17144 ± 2 Da in all samples. This protein has been termed roborovskin. The primary structure of roborovskin was determined by tandem mass spectrometry of peptides derived from independent and overlapping digestion with 3 proteases, supported by Edman degradation of the protein N-terminus. Roborovskin shared significant homology with olfactory-binding proteins from Myodes glareolus (bank vole) and with aphrodisin and submandibular protein from the golden hamster Mesocricetus auratus, all of which belong to the lipocalin superfamily. Lower levels of homology were also indicated between a variety of other lipocalins including the major urinary proteins from house mice and Norway rats. A model of the tertiary structure of roborovskin was constructed from the primary sequence by homology modeling. This model structure resembled other 8-stranded beta barrel lipocalins. Thus, the Roborovski hamster may demonstrate another variant of urinary lipocalin expression, as for the animals studied here, there appears to be no polymorphism in expression either between sexes or individuals.

New insights into the karyotypic evolution in muroid rodents revealed by multicolor banding applying murine probes

Muroid rodents are composed of a wide range of species characterized by extensive karyotypic evolution. Even if this group includes such important laboratory animal models as domestic mouse (Mus musculus), Norway rat (Rattus norvegicus), Chinese hamster (Cricetulus griseus), and golden hamster (Mesocricetus auratus), comparative cytogenetic studies between rodents are difficult due to the characteristic rapid karyotypic evolution. Molecular cytogenetic methods can help resolve problems of comparing muroid chromosomes. Here, we used cross-species comparative multicolour banding with probes obtained from mouse chromosomes 3, 6, 18, and 19 to study the karyotypes of nine muroid species from the three subfamilies Murinae, Cricetinae, and Arvicolinae. Results from multicolour banding with these murine probes (mcb) allowed us to improve the comparative homology maps between these species and to obtain new insights into their karyotypic evolution. We identified evolutionary conserved chromosomal breakpoints and revealed four previously unrecognized homologous segments, four inversions, and 14 evolutionary new centromeres in the nine muroid species studied. We found Mus apomorphic rearrangements, not seen in other muroids, and defined several subfamily specific chromosome breaks, characteristic for Arvicolinae and Cricetinae. We show that mcb libraries are an effective tool both for the cytogenetic characterisation of important laboratory models such as the rat and hamster as well as elucidating the complex phylogenomics relationships of muroids.

Desynchronisation of circadian activity rhythms in golden hamsters (Mesocricetus auratus) housed in deep bedding

In the wild, golden hamsters live in deep burrow systems, and hidings like shelters or burrows should also be available to animals in captivity. The aim of the present paper was to investigate putative effects on the circadian activity rhythm of golden hamsters with bedding material as enrichment. Three different bedding depths (10 cm, 40 cm, 80 cm) were investigated in 45 males (15 per group) kept singly. Their wheel-running activity was recorded continuosly. The light–dark cycle was 12:12 h with 30-min dusk and dawn periods. Activity onsets coincided well with lights-off in low bedding depth, but in the groups with 40 and 80 cm the activity rhythms did free run with a significant increase in tau with bedding depth. All hamsters in medium and deep bedding built and lived in self-constructed burrows. It is possible the difference in light intensity between light (50–85 lux) and dark conditions (0.5–2 lux) might have been too low. As a consequence the LD zeitgeber was not strong enough to entrain the activity rhythms, though the light was bright enough to stop running at least in some animals (masking). Hamsters of the low bedding group were continuously exposed to the light–dark cycle and thus were able to synchronise their activity rhythm. We conclude that bedding depth can influence the circadian rhythm of golden hamsters which has to be taken into account when performing chronobiological studies.

Activity measurement by three different techniques in golden hamsters (Mesocricetus auratus): a comparison between burrow systems and standard cages

In a previous study, golden hamsters living in self-constructed burrows showed reduced running wheel activity and decreased activity outside the burrows compared with animals without the possibility to dig burrows. Since different activity apportionments might account for that, different activity measurements were performed to show the relationship of different parts of general activity: running-wheel activity, activity inside and activity outside the bedding. Twelve hamsters in low bedding (<10 cm) were compared with 12 hamsters in deep bedding (80 cm). To further test the synchronisation to the light system, the animals were observed under light–dark (L:D) and under constant dark (D:D) conditions. Hamsters in deep bedding were significantly less synchronised to the light system, developed longer circadian rhythms tau (τ), had later activity onsets in the running wheel and a lower running wheel activity than hamsters in low bedding cages. Their activity onsets inside the bedding were later. Time differences between the onset of movements inside the bedding and the onset of running wheel activity were not significant. Thus, the later appearance of golden hamsters kept in deep bedding was not fully compensated by more activity inside the burrows.

Food hoarding behaviour in the golden hamster (Mesocricetus auratus): effects of body weight loss and hoard-size discrimination.

Two experiments investigated some of the factors that influence food hoarding behaviour in the golden hamster (Mesocricetus auratus). In Experiment 1, hamsters given limited access to food failed to increase the amount of food they consumed at each meal. Instead, they exhibited a significant increase in the amount of food taken to hoard during the limited access period, and this permitted hamsters who were allowed to retain their hoard to maintain body weight at levels comparable to free-feeding controls. Hamsters that were not allowed to retain hoarded food rapidly lost body weight. There was also an inverse correlation between body weight and amount of food taken to hoard in all hamsters given limited access to food, suggesting that body weight loss was one factor directly related to increased hoarding during periods of limited food accessibility. Experiment 2 investigated the effect of hoard-size discrimination on food hoarding in hamsters by artificially manipulating hoard size. The results suggested that hoarding behaviour could be influenced by artificially depleting and repleting the hoard, and this factor appears to influence hoarding in the absence of any significant changes in body weight. These results are discussed in relation to the kinds of adaptive feeding strategies that hamsters may utilize in their natural environment.

Schistosome albumin is of host, not parasite, origin

Recent work has implicated schistosome albumin as part of a mechanism for neutralizing the oxidative assault by host immune defenses and suggested that the gene had been acquired by horizontal transfer from the mammalian host. In the course of proteomic analyses of Schistosoma mansoni adult worm vomitus and eggs recovered from mice, we identified numerous peptides, largely derived from murine rather than parasite albumin. We therefore conjectured that the supposed S. mansoni albumin sequence deposited on GenBank might be the result of contamination rather than horizontal gene transfer. Based on phylogenetic analysis the most likely source was the Syrian (golden) hamster Mesocricetus auratus. Proteomic analysis of Syrian hamster albumin generated peptide identities to S. mansoni as the top hit, with a high ion score >1,500 and 63% coverage of the translated cDNA sequence. RT-PCR using specific primers permitted amplification of the M. auratus albumin transcript, which is identical to the deposited S. mansoni albumin sequence. PCR amplification of a fragment of the M. auratus albumin gene from genomic DNA suggests a homologous structure to the Mus musculus albumin gene. We were unable to find the S. mansoni albumin gene sequence by in silico searching on either version 3 of the S. mansoni genome assembly or the >3 million shotgun DNA reads. Finally, Southern blotting detected the albumin gene in M. auratus but not in S. mansoni genomic DNA, even when the latter was present in a 10-fold excess. Collectively, our data make the strongest case that the schistosome albumin protein described in previous reports is of host origin and all nucleotide-derived data are the result of contamination with host material. By analogy, we suggest that other reported examples of horizontal gene transfer to schistosomes might similarly be explained by complementary/genomic DNA contamination.