Gerbils Research Articles

Comparative Mitogenome Analysis of Gerbils and the Mitogenome Phylogeny of Gerbillinae (Rodentia: Muridae).

To enrich the mitogenomic database of Gerbillinae (Rodentia: Muridae), mitogenomes of three gerbils from different genera, Meriones tamariscinus (16,393bp), Brachiones przewalskii (16,357bp), and Rhombomys opimus (16,352bp), were elaborated and compared with those of other gerbils in the present study. The three gerbil mitogenomes consisted of 2 ribosomal RNA genes, 13 protein-coding genes (PCGs), 22 transfer RNA genes, and one control region. Here, gerbil mitogenomes have shown unique characteristics in terms of base composition, codon usage, non-coding region, and the replication origin of the light strand. There was no significant correlation between the nucleotide percentage of G+C and the phylogenetic status in gerbils, and between the GC content of PCGs and the leucine count. Phylogenetic relationships of the subfamily Gerbillinae were reconstructed by 7 gerbils that represented four genera based on concatenated mitochondrial DNA data using both Bayesian Inference and Maximum Likelihood. The phylogenetic analysis indicated that M. tamariscinus was phylogenetically distant from the genus Meriones, but has a close relationship with R. opimus. B. przewalskii was closely related to the genus Meriones rather than that of R. opimus.

Leishmania spp. infection in Rhombomys opimus and Meriones libycus as main reservoirs of zoonotic cutaneous leishmaniasis in central parts of Iran: Progress and implications in health policy

Rodents from the subfamily Gerbillinae are the principal reservoir of cutaneous leishmaniasis (CL) caused by Leishmania major in the center and northeast of Iran. This study was conducted to determine both naturally occurring Leishmania infection rates and the distribution of Leishmania species in the central parts of Iran during 2019-2020. In this regard, presence of Leishmania parasites were confirmed by microscopic examination and the species were identified by nested-PCR using the Internal Transcribed Spacer2- Ribosomal DNA (ITS2-rDNA). Finally, some samples were sequenced and, the blast analysis of L. major samples, showed a 92.45-100% homology to the L. major sequence. Of the 181 wild gerbils collected (Rhombomys opimus=157 and Meriones lybicus=24), 88 (48.6%) tested positive for Leishmania sp. by microscopic examination whereas 162 (89.5%) were positive by nested-PCR. Of the 162 infected gerbils, 103 showed single strain infections (30L. major, 28L. gerbilli and 45L. turanica), 43 showed dual infections with only the non-human species (L. gerbilli and L. turanica), and 16 were mixed infections of L. major and L. turanica (n=14) or L. gerbilli (n=2). All single or mixed L. major infections were detected in gerbils from areas with reports of human CL during the last decade. These findings suggest that Rhombomys opimus and Meriones libycus have a potential role in the maintenance of human and non-human transmission of Leishmania species in the CL foci.

First genetic identification of Sundevall’s jird Meriones crassus (Rodentia, Muridae) in Morocco and the hypothesis of range extension

Rodents from the subfamily Gerbillinae Gray, 1825, are an important component of small fauna in arid and desertic regions in Africa and Asia. Among this group of rodents, Sundevall’s jird, Meriones crassus, is one of the most widespread desert species, found in countries ranging from Morocco to Pakistan. In this study, we sequenced the cytochrome b gene of the mitochondrial DNA in two specimens captured in Morocco, constituting the first genetic identification for this species in the African continent. Molecular identification was complemented and supported with morphological evidence. Additionally, we propose the hypothesis of a northward extension of 250 km of the geographic distribution of Sundevall’s jird in Morocco, perhaps indicating the increasing desertification affecting North Africa. Further evidence will be required to test the latter hypothesis. Dataset published through Zenodo (Doi: 10.5281/zenodo.4674889)

Nattokinase reduces brain infarction, fibrinogen and activated partial thromboplastin time against cerebral ischemia-reperfusion injury

Natto is a traditional Japanese food prepared from fermented soybeans. nattokinase (NK) is considered one of the most active functional ingredients in natto. The present study evaluated the neuroprotective effects of NK in gerbils subjected to focal cerebral ischemia. The gerbils were separated into four groups: control group, ischemic group and two NK groups (4 and 40 mg/day i.g. for 7 days). All gerbils were fed standard chow with or without NK prior to cerebral ischemia. Focal cerebral ischemia was induced by the occlusion of the right common carotid artery and middle cerebral artery for 60 min, followed by reperfusion. Infarct volumes were determined by 2, 3, 5-triphenyltetrazolium chloride staining. Anti-thrombotic effects of NK, such as fibrinogen, prothrombin time and activated partial thromboplastin time, were also determined. Our data showed that NK significantly reduced infarct volumes by 54-68% (p ＜ 0.01), compared to the ischemic group. Prothrombin time was not significantly different in all groups. However, low dosage NK (4 mg/day) reversed ischemic-induced increase in fibrinogen concentrations and activated partial thromboplastin time. In summary, the data indicated that oral intake of NK for 7 days may alter fibrinolytic activity and provide neuroprotective effects against focal cerebral ischemia in gerbils.

Effects of swimming rehabilitation training on learning and memory function and CaMK II in gerbils with cerebral ischemia reperfusion

Objective To explore the protective effect and mechanism of swimming rehabilitation training on learning and memory impairment of cerebral ischemia reperfusion gerbil. Methods Forty adult healthy male gerbils were randomly divided into sham group, sham+ swimming group (Sham+ S group), cerebral ischemia / reperfusion group (I/R group), cerebral ischemia/reperfusion+ swimming group (I/R+ S group), with 10 rats in each group. The gerbil models of cerebral ischemia/reperfusion in I/R group and I/R+ S group were established by blocking bilateral common carotid artery, while for gerbils in Sham group and Sham+ S group, only bilateral common carotid arteries of gerbils were exposed, but no arteries were clamped. Morris water maze was used to detect the changes of learning and memory function in rats.Oxidative stress injury in hippocampal neurons was detected by detection kit analysis.And the expression of Bax, Bcl-2 and CaMK Ⅱ protein in hippocampal tissue was detected by Western blot. Results Compared with Sham group, the gerbils in I/R group had longer positioning cruise time and less shuttle times (both P<0.01). Compared with I/R group, the positioning cruise time and shuttle times in I/R+ S group were significantly shortened and increased respectively (both P<0.01). Compared with sham group(SOD: (123.13±7.50)U/mg, GSH: (42.10±2.17)μg/g, GSH-Px: (61.37±2.51)μg/g, MDA: (2.91±0.23)nmol/mg), the activities of SOD, GSH, GSH-Px in I/R group decreased significantly, while the content of MDA increased significantly(SOD: (75.50±6.96)U/mg, GSH: (22.50±1.64)μg/g, GSH-Px: (33.15±2.04)μg/g, MDA: (5.96±0.32)nmol/mg; all P<0.01). Furthermore, compared with I/R group, the above indexes in I/R+ S group were significantly reversed(SOD: (110.30±5.90)U/mg, GSH: (34.31±1.73)μg/g, GSH-Px: (50.13±2.31)μg/g, MDA: (3.57±0.29)nmol/mg; all P<0.01). Compared with Sham group, the expression of Bax protein in hippocampus of gerbils in I/R group was increased, while the expression of Bcl-2 protein and p-CaMK Ⅱ protein was decreased (all P<0.05). Compared with I/R group, the expression of Bax protein in hippocampus of gerbils in I/R+ S group was decreased, while the expression of Bcl-2 protein and p-CaMK Ⅱ protein was increased (all P<0.05). Conclusion Swimming rehabilitation training can improve learning and memory impairment of gerbils after ischemia-reperfusion through anti-oxidative stress and anti-apoptosis, which may be related to CaMK Ⅱ signaling system. Key words: Cerebral ischemia/reperfusion; Rehabilitation training by swimming; Calcium/calmodulin-dependent protein kinase Ⅱ; Learning and memory function; Gerbil

Baluchistan Gerbil hepatotoxicity as a new biomonitor of heavy metal pollution

Hepatotoxicity was targeted in Baluchistan Gerbil (Gerbillus nanus) as a biomonitor of pollution with heavy metals near Al-Asfar lake in Al-Ahsa province, KSA. The study showed as compared to reference animals that polluted gerbil’s liver recorded significant increase of lead and copper and significant decrease of zinc contents. In addition to significant decrease in RBC count, hemoglobin content, hematocrit percentage, MCH, MCV and MCHC. Also, significant increase in serum liver enzymes (aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase) activity was observed. Liver oxidative stress (OS) was evidenced by significant increase in, malondialdehyde level and significant decrease of superoxide dismutase and catalase enzyme activities. Light and ultra-histopathological results assessed the liver tissue impairment. In conclusion, the present study suggested that lead and copper could be the major heavy metals serving hepatotoxicity in gerbils. This study present Gerbillus nanus as the first bio monitor in native wild mammal in Al-Ahsa.

Common diseases of gerbils

Gerbils are members of the subfamily Gerbillinae, family Muridae, with the Mongolian gerbil (Meriones unguiculatus) being the most common pet species of gerbil available in the UK; they originate from desert regions. Gerbils come in various colourations and are highly social, nocturnal species, creating elaborate underground burrowing systems. While active, they are easily handled and can make good pets. Gerbils are medically more robust than some other rodent species commonly kept as pets; nevertheless there are a number of diseases that are seen in pet gerbils, and the veterinary surgeon should be aware of these. A number of antibiotics have been associated with development of intestinal dysbiosis and fatal enterotoxaemia in gerbils, and their use should be avoided.

Gerbils hear the light

Gerbils hear the light

Arthrospira platensis improves macrophages arginine metabolism and prevents insulin resistance in Psammomys obesus

Introduction: Chronic low grade inflammation is generally linked to the development of obesity-related metabolic diseases and tissue-resident macrophages play a major role in the regulation of the inflammation markers in the tissues. The cyanobacterium Arthrospira platensis also named spirulina is a blue green microalgae which has anti-inflammatory and anti diabetic properties. This study aimed to evaluate its potential therapeutic benefits on insulin resistance and peritoneal macrophages arginine metabolism in experimental gerbils named Psammomys obesus. Methods: A control group was fed its vegetable -based low caloric diet (halophilic plants). Two experimental groups were fed a high caloric diet for 12 weeks. Spirulina, or its vehicle (0.9% NaCl solution) were administrated daily by gastric intubation during 12 weeks. At the end of experiments, serum was collected to assess biochemical parameters and arginine metabolism was studied from isolated peritoneal macrophages. Results: Spirulina attenuated hyperlipidemia and prevented hyperinsulinemia, avoiding metabolic disturbances. Psammomys fed a high caloric diet displayed macrophages arginine metabolism toward pro-inflammatory phenotype while spirulina supplementation maintained peritoneal macrophages’ iNOS activity similar to that of the control group. Conclusion: Our study suggests that Arthrospira platensis is effective in improving insulin sensitivity by regulating peritoneal macrophages’ arginine metabolism.

Expression of vascular endothelial growth factor and microvessel density in gerbil model with inoculated hepatic alveolar echinococcsis

Objective To study the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD, CD34) in inoculated hepatic alveolar echinococcsis gerbil model and explore the clinical significance. Methods Sixty healthy gerbils were randomly divided into model group, control group and sham operation group. Each gerbil in both model and control groups had liver vaccination with 0.1 ml immature alveolar echinococcus protoscolex suspension or 0.1 ml phosphate buffered saline by open abdominal surgery, respectively, and the sham operation group only had abdominal surgical procedures. Gerbils were put to death on the 120th day post operation, extracted the eyeball and drawn the blood. The alveolar hydatid tissue, surrounding and distal liver tissue were removed from the model group, and normal liver tissue was collected from the other two groups. The VEGF and MVD-CD34 expression was detected by immunohistochemistry staining, Western Blot, and enzyme-linked immunosorbent assay (Elisa). Results Liver alveolar echinococcsis tissue was only observed in model group. The VEGF expression was observed as yellow or brown yellow granules located in the cytoplasma. The VEGF score and VEGF/β-actin ratio in the different parts were 5.13±1.81 and 1.12±0.05, 4.20±1.52 and 0.91±0.02, 2.46±1.06 and 0.28±0.02, 2.20±0.77 and 0.30±0.02, 2.13±1.72 and 0.25±0.01, respectively. The VEGF expression in different histological sites showed a gradient change, and bubble hydatid tissues had the highest VEGF expression (P<0.05). CD34 was expressed in alveolar hydatid tissue and surrounding liver tissue in model group and the CD34 positive cells was stained brown, while CD34 was mainly located in the cell membrane of endothelial cells. The CD34 scores and the CD34/β-actin ratio in the different parts were 5.06±2.46 and 0.66±0.01, 2.43±1.26 and 0.58±0.02, and the other tissues did not have CD34 expression. The alveolar hydatid tissue had higher CD34 expression than any other tissues (P<0.05). The respective serum VEGF and CD34 level in each group was (106.17±14.17)pg/ml, (38.13±21.36)pg/ml, (42.88±17.25)pg/ml, and (1.47±0.28)ng/ml; (0.82±0.12)ng/ml, (0.72±0.16)ng/ml, both are higher in model group than those in the other groups with statistical significance (P<0.05). Conclusion Angiogenesis is detected in gerbil alveolar hydatid tissues, which might be involved in the infiltrating growth of alveococcus. Key words: Alveolar echincoccosis, hepatic; Vascular endothelial growth factor; Microvessel density; Angiogenesis

Phylogenetic analysis of the Mongolian gerbil (Meriones unguiculatus) from China based on mitochondrial genome.

Meriones unguiculatus (Gerbillinae, Rodentia) is widely used as an animal model of human disease. Here, we provide the first report of the complete mitochondrial genome sequence of M. unguiculatus (GenBank accession Nos. KF425526 and NC_023263). The sequence contained the conserved vertebrate pattern of 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and 1 major noncoding region. We identified one extended termination-associated sequence and one conserved sequence block in the non-coding region. The putative origin of replication for the light strand (OL) was 35 bp long. The OL stem and adjacent sequences were highly conserved, but the loop region differed from those of other rodent species. Base composition and codon usage of the 13 protein-coding genes in M. unguiculatus were compared with those of 23 rodent species with previously sequenced mitochondrial genomes. An A+T content of 63.0% was present in M. unguiculatus; this is similar to the Murinae average (62.4 ± 0.8%) and falls between the average for Mus musculus (63.1 ± 0.1%) and Rattus sp (61.7 ± 0.4%). The AT and GC skew values of M. unguiculatus were 0.035 and -0.28, respectively, similar to those of Cricetinae species (0.057 ± 0.05 and -0.31 ± 0.05). The codon families exhibited similar abundance in all 24 species. Analysis of phylogenetic relationships with 23 other rodent species using neighbor-joining and maximum likelihood protocols and the 12 protein-coding regions on the H strand showed that M. unguiculatus should be classified as genus Meriones, sub-family Gerbillinae, family Muridae.

English

English

The effect of scalp acupuncture combined with rehabilitation training on the regulation of neuro-plasticity-associated protein MAP-2 in gerbils modelling cerebral ischemia and reperfusion

Objective To observe the effect of scalp acupuncture and rehabilitation training on the regulation of neuro-plasticity-associated protein MAP-2 in gerbils modelling cerebral ischemia and reperfusion. Methods Cerebral ischemia and reperfusion were modelled into thirty-six male gerbils. They were then randomly divided into a model group (A), a scalp acupuncture and rehabilitation training group (B) and a rehabilitation training group (C), each of 12 cases. The scalp acupuncture and rehabilitation training were administered daily to the gerbils in group B beginning 24 h after modeling, for 14 d. Any changes in Bederson scores were observed after one, 7 and 14 days. On the 14th day the expression of MAP-2 around the infarct focus was detected using western blotting in all 3 groups. Results On the 7th day the average Bederson score in group B (1.81±0.52) was not significantly different from that in group A (2.13±0.49) or group C (2.00±0.31) (P>0.05). At the end of the treatment, however, there were significant differences between the groups, with group B(0.47±0.31) scoring significantly better than groups C(1.04±0.63) and A(1.46±0.72)(P<0.05). Group C was also significantly better than group A (P<0.05). The expression of MAP-2 as measured as integrated optical intensity (IOD) in group B (0.91±0.18) was significantly higher than that in group A (0.43±0.21) and group C (0.67±0.24) (P<0.05); so was group C compared to group A (P<0.05). Conclusion The scalp acupuncture combined with rehabilitation training can improve the recovery of motor function and enhance the expression of neuro-plasticity-associated protein MAP-2 in gerbils with after cerebral ischemia and reperfusion. Key words: Cerebral ischemia-reperfusion; Scalp acupuncture; Microtubule-associated protein 2; Gerbil; Acupuncture

Establishment of Mongolian gerbil model of gastric cancer induced by Helicobacter pylori infection and its proteomics analysis

To establish an animal model of gastric cancer by long-term infection of Helicobacter pylori (H.pylori) and to elucidate the pathogenesis by proteomics analysis. Fifty male Mongolian gerbils (4-5 week-old and weighted 60-100 g) were infected with H.pylori and the gastric tissues were obtained after the infection at 3, 6, 12 and 24 months. Histological changes were evaluated by H-E staining of the gastric tissue sections. Detection of H.pylori was performed by in-vitro culture of fresh gastric tissue samples, PCR amplification of H.pylori 16s rRNA and localization by silver staining. In addition, proteins extracted from gastric tissue samples were subjected to two-dimensional electrophoresis (2-DE) at various infection time points. Protein spots with increased quantity over the course of H.pylori infection were selected and analyzed by LC-MS/MS. Finally, differentially expressed proteins between human gastric cancer tissue samples and lymph nodes were analyzed by real-time RT-PCR. Colonization of H.pylori was observed in gastric tissue of gerbils as early as 3 months after H.pylori infection, and persisted till 24 months. Pathological examination of infected animals showed various histological changes including acute gastritis, atrophic gastritis, intestinal metaplasia and gastric carcinoma. Seventy-eight differentially expressed proteins were identified by proteomics analysis, among which 36 proteins were up-regulated and 42 were down-regulated. Analyzed by LC-MS/MS, ten proteins were identified, including lactate dehydrogenase, ATP synthase, fatty acid-binding protein, COX5B, peroxiredoxin-4, peroxide reductase, transgelin, succinyl-CoA ligase, keratin and protein disulfide-isomerase A2, among which transgelin, ATP synthase and lactate dehydrogenase were highly expressed in human gastric carcinoma and lymph nodes. H.pylori infection induces the expression of transgelin, ATP synthase and lactate dehydrogenase, implying possible roles in the pathogenesis of gastric diseases including cancer.

Study on the spatial and temporal distribution of animal plague in Junggar Basin plague focus

To explore the spatial and temporal distributions of animal plague in Junggar Basin natural plague focus. Data regarding plague antibody (F1) in serum of Great Gerbil (Rhombomys opimus, R. opimus) which were collected from 2005 to 2012 in Junggar Basin and analyzed. The changing rates on the positivity of F1 that appeared spatially and temporally were also analyzed. A total of 4 825 R. opimus serum samples were collected in 13 administrative regions in Junggar Basin. showed that plague R. opimus existed in two areas-Gurbantonggut desert in the eastern-center and the clay desert of western Junggar Basin. However, in these two areas, the intensity of animal plague prevalence was different. In the former region where Yesinia pestis positive serum was detected from R. opimus, the detected rate of R. opimus was 8.39%. However, in the latter areas, the average positive rate was 1.56%. The changing trends of R. opimus plague prevalence were also varied annually. In the western Junggar Basin, the trend showed a slowly downward profile. The serum positive rate of R. opimus for Yesinia pestis decreased, from 7.59% in 2005 to 0.61% in 2008, and appeared as a resting state that none of the positive sample could be found since then. However, in the eastern-center Junggar Basin area-also named as Gurbantonggut desert which had been divided into 3 segments(western, central and eastern, according to related geographical characteristics), the changing trends of animal plague seemed quite complex. In the western segment, the animal plague had two epidemic peaks-in 2006 and 2010, with the interval of 4 years, with the higher peak of all the three geographic segments as 45.65% in 2010 and the positive serum of R. opimus for plague could be detected each year from 2006 to 2012. However, there were 3 epidemic peaks in the same period in the central and eastern segments. In the central segment, the peaks appeared in 2006, 2009 and 2011, with the intervals as 2.5 years and the average positive rate 8.92% was seen the lowest in Gurbantonggut desert. In the eastern segment, the first 2 peaks appeared the same season as in the central segment, but the third peak appeared in 2012, with the peak interval as 3 years. The positive rate of R. opimus for plague was also different in seasons, with the positive rate higher in autumn than in spring. These findings showed that the animal plague could be continuously prevalent from spring to autumn in the natural foci of plague in the Junggar Basin. Both geographical and temporal fluctuations of animal plague existed in the natural foci of Junggar Basin which was also named as geographical heterogeneity. Consequently, animal plague could be divided into two areas-the clay plains desert in the western and the Gurbantonggut desert in the eastern-center Junggar Basin.

Effects of Helicobacter pylori on the expression of catalytic subunit of the DNA-dependent protein kinase and Ku70/Ku80 heterodimer in gastric mucosa epithelial cells in vivo and in vitro

Objective To explore the effects of Helicobacter pylori (H.pylori) on the expression of catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs) and Ku70/Ku80 heterodimer in gastric mucosa epithelial cells in vivo and in vitro.Methods After treated with H.pylori for one,three,six,12 and 24 hours,the expressions of DNA-PKcs and Ku70/Ku80 heterodimer in gastric epithelial cells (GES) 1 and gastric adenocarinoma cells (AGS) were detected by Western blot.Mongolian gerbils were gavaged with H.pylori,and were sacrificed after infected for six and 12 months.The gastric mucosa tissues were taken for immunohistochemistry to detect the expressions of DNA-PKcs and Ku70/Ku80 heterodimer at protein level.The data were analyzed by t test and chi-square test.Results After H.pylori infection for one hour,the relative quantity of the expression of DNA-PKcs in GES-1 was 1.16±0.09,which was higher than that of non infected group (1.04±0.31) and the difference was statistically significant (t=4.67,P＜0.05).After infected by H.pylori for one,three,six,12 and 24 hours,the relative quantities of the expressions of Ku70/Ku80 heterodimer in GES-1 were 1.58±0.32,1.84±0.40,1.97±0.35,3.72±1.42 and 3.74±1.56,respectively,all were higher than that of non infected group (1.24±0.31) and the differences were statistically significant (t=3.57,4.20,5.03,8.11 and 8.14,all P＜0.05).The relative quantities of the expressions of Ku70/Ku80 heterodimer in AGS were 4.69 ± 0.87,3.67 ± 0.67,2.41±0.24,1.35±0.35 and 1.32±0.10 after H.pylori infected for one,three,six,12 and 24 hours,respectively,all were lower than that of no H.pylori infected group (4.84 ± 0.76) and the differences were statistically significant (t=34.13,27.68,19.81,4.47 and 5.69,all P＜0.05).In Mongolian gerbil models,DNA-PKcs did not express in H.pylori negative group (0/25),the total positive rate of H.pylori infected group was 98.1％ (53/54),the difference between the two groups was statistically significant (x2 =74.55,P＜0.01).The total positive rate of Ku70/Ku80 heterodimer in H.pylori negative group was 92.0％ (23/25) and in H.pylori infected group was 68.5％ (37/54),the difference between the two groups was statistically significant (x2=5.16,P＜0.05).Conclusion H.pylori infection affected cellular DNA damage repair through changing the expression of DNA-PKcs and Ku70/Ku80 heterodimer in gastric mucosa in vivo and in vitro,which may cause gastric mucosal lesions. Key words: DNA-binding proteins; Catalytic domain; Protein kinases; Fibrin fibrinogen degradation products; DNA damage; Helicobacter pylori; Gerbillinae

Distribution of interstitial cells of Cajal in Meriones unguiculatus and alterations in the development of incomplete intestinal obstruction.

The interstitial cells of Cajal (ICCs) act as pacemaker cells that are involved in gastrointestinal (GI) motility disorders, although the pathogenesis of these disorders is still unclear. The GI tract of Mongolian gerbils shares similar anatomical features with that of humans, but no investigation of ICCs has been reported in the GI tracts of this animal. In the present study, we first observed the distribution and morphological features of ICCs in the Mongolian gerbil GI tract. The ICCs were mainly distributed within the smooth muscle layers (ICC-IM), the myenteric plexus (ICC-MY), the deep muscular plexus in the small intestine (ICC-DMP) and the submucosal surface of the circular muscle layer in the colon (ICC-SM). The density of the ICC-IM gradually decreased from the stomach to the colon, whereas the density of the ICC-MY gradually increased. Second, we compared differences in the ICCs between the control and obstructed intestines, and no significant difference was observed in the number of ICCs after 7 days of obstruction. However, the numbers were reduced by approximately day 14 of obstruction. The pattern of immunoreactivity also partly differed from that of the control group, i.e., a scattered and interrupted network of ICCs was often observed. Western blotting revealed that p-Kit and SCF were significantly reduced in the dilated intestines by day 14. Our results indicate that the Mongolian gerbil may be a good animal model for studying changes in ICCs that may contribute to the pathogenesis of GI motility disorders.

Tracking Chromosome Evolution in Southern African Gerbils Using Flow-Sorted Chromosome Paints

Desmodillus and Gerbilliscus (formerly Tatera) comprise a monophyletic group of gerbils (subfamily Gerbillinae) which last shared an ancestor approximately 8 million years ago; diploid chromosome number variation among the species ranges from 2n = 36 to 2n = 50. In an attempt to shed more light on chromosome evolution and speciation in these rodents, we compared the karyotypes of 7 species, representing 3 genera, based on homology data revealed by chromosome painting with probes derived from flow-sorted chromosomes of the hairy footed gerbil, Gerbillurus paeba (2n = 36). The fluorescent in situ hybridization data revealed remarkable genome conservation: these species share a high proportion of conserved chromosomes, and differences are due to 10 Robertsonian (Rb) rearrangements (3 autapomorphies, 3 synapomorphies and 4 hemiplasies/homoplasies). Our data suggest that chromosome evolution in Desmodillus occurred at a rate of ∼1.25 rearrangements per million years (Myr), and that the rate among Gerbilliscus over a time period spanning 8 Myr is also ∼1.25 rearrangements/Myr. The recently diverged Gerbillurus (G. tytonis and G. paeba) share an identical karyotype, while Gerbilliscus kempi, G. afra and G. leucogaster differ by 6 Rb rearrangements (a rate of ∼1 rearrangement/Myr). Thus, our data suggests a very slow rate of chromosomal evolution in Southern African gerbils.

THE SPECTER OF PREDATION: THE EFFECTS OF VIPERS ON THE FORAGING BEHAVIOR OF TWO GERBILLINE RODENTS

ABSTRACT Predation may have profound effects on individual growth rates, population dynamics, and species interactions via its influence on prey foraging behavior. Here, we examine the response of two gerbil species (Gerbillus alletibyi and G. pyramidum) to greater sand vipers (Cerastes cerastes) and to added illumination (a factor associated with increased risk of predation from owls). We measured gerbil foraging behavior using the number of seed trays (resource patches) foraged and amount of seed resources left in each tray (giving-up densities; GUDs). Fewer seed trays foraged and higher GUDs indicate a higher perceived risk of predation. Accordingly, G. allenbyi foraged fewer seed trays in response to illumination and in the open microhabitat. In addition, vipers may have affected foraging activity in both gerbil species and caused G. pyramidum to forage in fewer trays in the bush microhabitat. Viper activity also caused both species to abandon seed trays at higher GUDs. Overall, gerbils altered their ...

KARYOTYPIC DATA ON RODENTS FROM SENEGAL

ABSTRACT New karyological data on rodents from Senegal are presented and compared with previous reports from other parts of Africa. Among the murid rodents, two clearly differentiated forms of Arvicanthis are described (2n = 62, NFa = 64 and 74), which confirms the probable polytypic structure of A. niloticus. On the other hand, such species as Myomys daltoni and Praomys tullbergi appear chromosomally stable over a large geographic range. Among the Gerbillidae studied, the karyotype of Desmodilliscus braueri (2n = 78, NFa = 104) is presented, as well as those of two species of Gerbillus newly reported for Senegal, G. henleyi (2n = 52, NFa = 59/60), and Gerbillus cf pyramidum (2n = 40, NFa = 74).