Rodent Research Articles

A cytotaxonomic survey of Rodents from Niger: implications for systematics, biodiversity and biogeography

Nous avons realise un inventaire des rongeurs du Niger qui s'appuie essentiellement sur des donnees cytotaxonomiques non ambigues a cause de la presence de nombreux complexes d'especes jumelles. Trente neuf especes ont pu etre recensees, l'une d'entre-elles correspondant a une nouvelle forme chromosomique de Taterillus. De plus, 3 cytotypes toujours sans attribution specifique ont ete retrouves (Mastomys sp., Tatera sp. et Acomys sp.) et des donnees caryotypiques nouvelles sont presentees pour Gerbillus nancillus, Graphiurus cf. parvus, Massouteria mzabi et Xerus erythropus. Les cartes de repartition de nombreuses especes peu connues sont completees. Aucun gradient n'est observe entre les faunes d'Afrique occidentale et celles d'Afrique orientale, les especes se repartissant essentiellement en fonction de la latitude. Le massif de l'Air apparait plutot comme un prolongement de la zone sahelienne que comme un refuge sahelien dans le Sahara. Parmi les especes de rongeurs inventoriees, cinq grands groupes biogeographiques peuvent etre distingues: 1) des especes infeodees a la zone soudanienne recevant moins de 700 mm; 2) un groupe d'especes tres largement reparties de la zone soudanienne (plus de 700 mm) au nord de la zone sahelienne, et incluant parfois des localites sahariennes; 3) des especes typiquement sahariennes; 4) des especes infeodees aux massifs sahariens montagneux; 5) quelques especes strictement commensales. Par ailleurs, la progression de plusieurs taxons vers le sud confirme la desertification du Sahel qui resulte a la fois d'une aridification naturelle et des activites humaines.

Considerations for an automated cage-processing system.

The author explains the advantages of installing automated cagewash systems when building or renovating laboratory animal facilities. Such automated systems lead to monetary savings and are also healthier for staff members who must wash thousands of soiled rodent cages.

Modification of the anal tape method for detection of pinworms in rodents.

A modification of Graham's anal tape technique for detection of oxyurid worm eggs involves a coverslip or microscope slide covered with a thin layer of adhesive. The worm eggs stick to the adhesive and can be directly observed under the microscope.

Treatment after rodent exposure necessary to avoid death from rabies

Treatment after rodent exposure necessary to avoid death from rabies

Partial characterization of an intra-acrosomal protein, human acrin1 (MN7).

Acrin1 (MN7), a 90-kd glycoprotein, is localized in the sperm acrosome of several rodents. The purpose of this study was to determine the molecular size and subcellular localization of acrin1 (MN7) in human sperm, and its organization in spermatids during spermiogenesis. Immunocytochemical and biochemical analyses revealed that acrin1 (MN7) is localized in the anterior acrosome and its molecular size is 90 kd, the same as in rodents. Based on molecular size, acrin1 (MN7) is likely to be a novel human acrosomal protein. During spermiogenesis, acrin1 (MN7) is initially localized in the head-cap portion of spermatids from the cap phase to the end of the acrosomal phase, and then relocates from the posterior to the anterior region of the acrosome in the maturation phase in spermatids. Such a morphological organization mechanism is also basically the same as that in rodents. Thus, acrin1 (MN7) is a common acrosomal protein of 90 kd in rodents and humans.

Maintaining diversity through intermediate disturbances: evidence from rodents colonizing rehabilitating coastal dunes

AbstractRodents inhabit the coastal dune forests of KwaZulu‐Natal, South Africa. Here habitat rehabilitation following mining of dunes has resulted in coastal dune forest succession similar to that recorded in nonmined forests. We investigated the colonization of rehabilitating stands and evaluate the role of disturbance in maintaining rodent diversity. A trapping programme was established between July 1993 and February 1995 during which rodent colonization, local extinction and species richness were recorded for rehabilitating stands of different ages. Trends in these variables were closely associated with one of three possible outcomes for a disturbed patch over time, with no intervening disturbances following the initial disturbance. Colonization was initially high which led to an increase in species richness. Extinction was lower than colonization, but became higher when the habitat was 3 years old, which led to a decline in richness. We extrapolate this result assuming negligibly small disturbances after the initiation of rehabilitation and suggest that intermediate levels of disturbance maintain rodent species richness in coastal dune forests. Furthermore, our results illustrated species turnover, a prediction of the recorded outcome, with young stands dominated by Mastomys natalensis and older stands by Saccostomus campestris or Aethomys chrysophilus.

The rodent route to celebrity

The rodent route to celebrity

Completion of human Chromosome 21, the Human Genome Project, and Steps towards Understanding Ourselves through Comparative Genomics

Chromosome 21 is the smallest human chromosome and represents a model for physical mapping of the entire human genome. Three copies of this autosome cause Down syndrome, the most frequent genetic disorder associated with significant mental retardation. Five years ago, in the framework of the international human genome project, and as an integrated part of the chromosome 21 community, a consortium, of academic groups from Japan and Germany was formed to map and sequence this chromosome. Several whole-genome and chromosome-specific DNA libraries were constructed for mapping purposes. Using a combination of nested-deletion [1] and shotgun sequencing approaches, our center determined and analyzed over 17 million bases of high-quality data. In total, over 33.5 million basepairs of DNA, distributed over four contigs, were sequenced with very high accuracy [2]. The largest of these contigs is nearly 25.5Mb long. Only three small clone gaps remain, which together comprise approximately 100kb. Thus, we achieved a coverage of 99.7% of 21q. In addition, 211,116 bp from the short arm were also sequenced. Analysis of the chromosome revealed far fewer genes than previously estimated. Instead of 800-1000 expected genes, we found only 225 genes, of which 127 are known genes and 98 are predicted genes. In addition, 59 pseudogenes were identified. The completion of the 21q sequence provides a unique resource for understanding the molecular pathophysiology of Down syndrome, as well as all other monogenic and complex disorders that map to this chromosome, including Alzheimer’s disease, leukemia, autoimmune disease, epilepsy and manic-depressive psychosis. It also stands as a structural framework from which the complete molecular architecture of the chromosome can be determined. With the announcement of the first “working draft” of the human genome by the international human genome sequencing consortium this past June, there has been a great interest in the total number of genes in the human genome[3]. Some of the current estimates range from as low as 34,000 genes to as high as 140,000 genes. The low gene-density of chromosome 21 was quite unexpected. Most striking is a 7-Mb region near the region near the centromere that contains only one gene. This region is much larger than the whole genome of some species, such as Escherichia coli, yet evolutionary processes permitted the existence of such a gene-poor SNA segment. This finding leads us to propose that there are additional large gene-less regions in other human/mammalian chromosomes. By combining the gene numbers of chromosomes 21 and 22 [4] (770genes; 2-3% of human genome) and assuming that together they represent the average gene content of the human genome, we estimate that the total number of human genes may be close to 40,000. As part of the international human genome sequencing project, we are also sequencing parts of chromosomes 11 and 18. Our high-throughput sequence production line generates about 10 Mb per day. In order to handle such a high volume of output, we have developed a system for automated data assembly, annotation and release. All the data is released through our website and through the DNA Database of Japan immediately according to the policies established by the international consortium. In addition to chromosomes 11, 18 and 21, we are also interested in the structure of the entire human genome. In collaboration with the University of Tokyo, we have developed a database called HGREP [5] (Human Genome Reconstruction Project) that contains working draft and finished sequences which cover more than 85% of the human genomic sequences. Sequence entries are aligned along the chromosomes based on sequence similarities to STS markers, BAC-end and other entry sequences. Further, biological features, such as genes, gene functions, repeats and CpG islands, are fully annotated on these entries. To identify evolutionally conserved and biologically important information in the genome, we are taking the strategy of comparative genomic sequence analysis between human and other related genomes such as those of rodents and primates. We are currently sequencing several regions of the mouse, including some regions that are counterpart to human chromosome 21, and are preparing genomic resources for sequencing of the chimpanzee. Through comparative methods, we are also trying to understand telomeric regions, structures at the end of chromosomes that play an important role in several biological functions and have been associated with human diseases like an oncogenesis and a cellular aging. The structure and function of all genes and their regulatory regions can only be fully understood by looking at how they interact under different circumstances and in several different backgrounds. Determining which genes and elements are human-specific will lead to a deeper understanding of who we are and will advance medical sciences drastically.

Transmembrane versus soluble stem cell factor expression in human testis.

The interaction between stem cell factor (SCF), a ligand produced by Sertoli cells, and its c-kit receptor on germ cells is necessary for successful spermatogenesis in animal models. SCF can be alternatively spliced into soluble and transmembrane forms, and it is the transmembrane form that is required for spermatogenesis in rodents. c-Kit receptors are also present on Leydig cells, and soluble SCF has been implicated in the regulation of testosterone production. This study had two goals: To test the hypothesis that the extent of germ cell production in human males is correlated with the expression of transmembrane SCF, and to examine the relationship between testosterone production and the expression of soluble SCF in humans. Reverse transcriptase polymerase chain reaction was used to determine the ratio of transmembrane-to-soluble SCF in testicular tissue. Clinical analysis, hormonal measurements, and histological methods were used to evaluate the causes of infertility and to seek correlations with the pattern of SCF expression. SCF was preferentially expressed as the transmembrane type in all testicular samples, regardless of the state of germ cell production. Furthermore, the percent of transmembrane SCF expression was independent of clinical and histopathological diagnosis (r(s) = 0.111, n = 28) and unrelated to the extent of spermatogenesis. This contrasts with rat models of testicular injury that exhibit a decreased proportion of transmembrane SCF with atrophy. A significant correlation (r(s) = 0.665, P < .02, n = 16) was found between testosterone levels and percent soluble SCF, which suggests that, in humans, there may be a regulatory interaction between soluble SCF and testosterone.

Global harmonization of laboratory rodent health surveillance standards.

The authors discuss the need for international standards for the microbiologic and genetic quality of rodents.

Red-carpet rodent care: making the most of dollars and sense in the animal facility.

Cutting-edge biomedical research programs have entered an era in which phenotypic characterizations for genetically altered rodents can facilitate appropriate care. The veterinary care requirements necessary to support such animal models can include the procedures already adapted as standard practice in companion animal hospitals, and can decrease data variability while increasing survival rates.

Rains, rodents, and unexplained deaths.

Rains, rodents, and unexplained deaths.

Spontaneous hyperplasia of the ventral lobe of the prostate in aging genetically hypertensive rats.

Recent studies have shown that the prostatic autonomic innervation takes part in its homeostasis and growth. Other works showed that spontaneously hypertensive rats (SHR) show excessive sympathetic activity, accompanied by lower urinary tract symptoms, increased growth capacity of prostatic stromal cells, and increased levels of androgens and their receptors. Furthermore, young SHR were reported to present incipient stages of benign prostatic hyperplasia (BPH). The aim of the present study was to examine whether this strain indeed develops spontaneous BPH with age, and can thus serve as a genuine natural model for this disorder. For this purpose, ventral lobes of prostates of one-year-old, male SHR and their normotensive counterparts, Wistar Kyoto (WKY) rats, were examined histopathologically, and the degree of hyperplasia was evaluated according to a score-chart protocol (histoscore). SHR exhibited severe adenomatous spontaneous BPH, characterized by piling-up of epithelial cells, with papillary formations, accompanied by a mild increase in the amount of fibrocytes and smooth muscle cells in the stroma. This was reflected by histoscore values of 38 +/-2. Thickening of prostatic arterioles also was noted, as well as mild chronic inflammatory exudate. WKY rats did not show any of these features of BPH despite their age (histoscore 17 +/- 3, significantly different from that of SHR). We conclude that SHR can serve as a rodent model for the spontaneous development of BPH with age, most probably due to the excessive neuroendocrine activity characteristic of this rat strain.

Experimental Stroke Alters Depressive-like Behavior in Mice.

P68 Depression is a common consequence of stroke in humans and is associated with an increase in cognitive deficits and impaired functional recovery. However, the etiology of post-stroke depression remains unknown. The purpose of the present study was to determine if focal cerebral ischemia in mice induces changes in a rodent behavioral model of depression that can be reversed through treatment with fluoxetine,a selective serotonin reuptake inhibitor. Increased time spent immobile versus actively swimming in the Porsolt Swim Test is a commonly used index of depressive-like behavior in rodents. Male C57/BL6 mice were subjected to a 2 min forced swim one day prior to 60 min middle cerebral artery occlusion (MCAO; using a 6.0 nylon filament) or sham-surgery. Beginning 7 days after surgery, the animals were injected IP daily with fluoxetine or the vehicle. One week later, the animals were subjected to a second swim test and the amount of time spent actively swimming versus immobile was recorded. Experimental stroke increased frequency and time spent immobile during the Porsolt Swim Test. Furthermore, chronic treatment of MCAO animals with 20 mg/kg of fluoxetine restored swimming behavior to SHAM levels (see table). These data suggest that post-ischemic affective disorders can be modeled in animals and are modulated by antidepressants.

Coadministration of bone marrow cells and an inhibitor of apoptosis (Z-VAD) promotes bone marrow cell survival and neurological functional recovery after focal cerebral ischemia in adult rat

P222 Most bone marrow cells (BMCs) transplanted into the ischemic brain of adult rodents die shortly after they are grafted, similar to the 90%-95% of the fetal cells that die after transplantation into Parkinson s patients. We tested whether coadministration of BMCs and Z-Val-Ala-DL-Asp-fluoromethylketone (Z-VAD), an inhibitor of apoptosis, into the ischemic boundary zone of the striatum and the cortex in rat brain promotes BMC survival. Adult Wistar rats were subjected to transient (2 h) middle cerebral artery occlusion (MCAo). At 1 d after ischemia, saline (n=9, Group 1); BMCs (1x10 6 in 10 :l, n=8, Group 2); or BMCs with Z-VAD (50 nM/ml, n=4, Group 3) were injected into brain. BMCs were harvested from donor adult rats injected with bromodeoxyuridine (BrdU, as a tracer). Rats were subjected to rotarod-motor and adhesive-removal somatosensory functional tests before MCAo and at 1 and 7 d after MCAo. Rats in Group 3 exhibited significant improvement (10.3±2.6 seconds, p 6 transplanted cells) increased significantly (p 6 cells) at 7 d. In the grafting areas, apoptotic cells were less clustered ( 240 per region) and apoptotic cells were significantly decreased (12.3±1.7/mm 2 vs. 25.9±2.1/mm 2 , ∼47%, p

Neurite Outgrowth Inhibition by Chondroitin Sulfate Proteoglycan: Stalling/Stopping Exceeds Turning in Human Neuroblastoma Growth Cones

Chondroitin sulfate proteoglycan (CSPG) inhibits outgrowth from embryonic chick and rodent neurons in vivo and in vitro and is upregulated during development and following injury. The role of CSPG in outgrowth from human neurons has been largely untested, but is critical for our understanding of regeneration in humans following nervous system injury. Here we determined the effects of CSPG on platelet-derived growth factor (PDGF)-stimulated neurite outgrowth from SH-SY5Y human neuroblastoma cells, a well-accepted model of neuronal differentiation. Cells were plated on glass coverslips adsorbed with laminin (LN), CSPG, or a patterned substratum consisting of alternating stripes of the two molecules. Similar to other studies using chick or rodent neurons, SH-SY5Y cells extend neurites on LN, displaying a 15.2% increase in the total neurite length/cell as compared to cells plated on glass. Cells plated on CSPG alone exhibited reduced neurite outgrowth compared to cells plated on glass or LN. Interestingly, SH-SY5Y growth cones extending on LN and then encountering a CSPG border display more stopping/stalling (62.3%) than turning (27.9%) behaviors. Soluble CSPG inhibits neurite initiation from SH-SY5Y cells plated on glass, but not on LN. These data demonstrate that several CSPG-elicited responses of human neuron-like cells are similar to those from nonhuman neurons. However, approximately 70% of SH-SY5Y growth cones stop or stall at a CSPG border while over 80% of chick sensory neurons turn at a CSPG border. The experimental difference between these models may well indicate a functional difference between animal and human neuronal regeneration.

Molecular scanning for mutations in the melanocortin-4 receptor gene in obese/diabetic Japanese.

Decreased function of the melanocortin-4 receptor (MC4R) was reported to cause late-onset obesity and insulin resistance in rodents. Thus mutations in the MC4R gene drew strong attention as a possible cause of obesity and diabetes. We screened for mutations in the MC4R gene in extremely obese [body mass index (BMI) > or = 35 kg/m2] Japanese with diabetes by direct sequencing. A heterozygous mutation (V103I) was detected in one case (2.0 %), however the frequency was not significantly different from that in non-obese (BMI < or = 24 kg/m2) and non-diabetic subjects (2.7 %). No other mutations were detected. These results suggest that mutations including V103I in the MC4R gene are not a major cause of obesity or diabetes in Japanese.

Measurement of prostate-specific antigen and human glandular kallikrein 2 in different body fluids.

It has been demonstrated that prostate-specific antigen (PSA), in spite of its name, can be detected in body fluids and tumors from a variety of organs. Investigations have shown that human glandular kallikrein 2 (hK2), a related prostate-secreted protease, can activate the zymogen form of PSA, suggesting that the two enzymes might work as a functional unit, with hK2 as the activator molecule and PSA as the effector molecule. If this is true, then hK2 should be found together with PSA in body fluids other than seminal plasma, as well. Recently, a sensitive and specific assay was devised for hK2, enabling its measurement in picogram quantities. With this assay, the concentration of hK2 was determined in samples of seminal plasma, amniotic fluid, breast milk, and saliva. Simultaneously, the samples were assayed for molecular forms of PSA. In seminal plasma, the mean PSA concentration was 0.82 mg/ml, while the hK2 level was around two orders of magnitude lower: mean value, 6.4 microg/ml. Approximately the same ratio of PSA to hK2 as in seminal plasma was found in amniotic fluid and breast milk, but in most samples, the hK2 values were too low for direct measurements and had to be concentrated prior to analysis. Measurable levels of PSA, all in the free form, were detected in amniotic fluid at the thirteenth week of gestation and then gradually increased to levels around and over 1 microg/L from the twentieth week. Significant levels of PSA were detected in amniotic fluid collected at delivery, also. Measurable levels of mammary PSA were primarily detected in colostrum, with a range from less than 0.03 microg/L to 2.1 mg/L. Around half of the molecules were in complex with protease inhibitor. Most surprisingly, determinations on saliva samples showed that none of them had detectable PSA levels but had measurable concentrations of hK2 with a mean value, 0.09 microg/L. The presence in saliva suggests that hK2 can be the human equivalent to one of the mouse salivary kallikreins with important biological function, like the epidermal growth factor-binding protein or the gamma subunit of nerve growth factor. However, this was ruled out, as a phylogenetic analysis showed that the human and mouse glandular kallikreins evolved independently from a common precursor after the separation of the primate and rodent lineages. In conclusion, the measurements show that in addition to the previously known secretion in seminal plasma, hK2 is secreted in amniotic fluid, breast milk, and saliva. Furthermore, the concerted expression of PSA and hK2 in seminal plasma, amniotic fluid, and breast milk suggests that the two proteases might form a functional unit but not always as demonstrated by the sole presence of hK2 in saliva.

Tumor profiles and carcinogenic potency in rodents and humans: Value for cancer risk assessment

Tumor profiles and carcinogenic potency in rodents and humans: Value for cancer risk assessment Romualdo Benigni a & Alessandro Giuliani b a Laboratory of Comparative Toxicology and Ecotoxicology , Istituto Superiore di Sanita’ , Viale Regina Elena 299, Rome, 00161, Italy E-mail: b Laboratory of Comparative Toxicology and Ecotoxicology , Istituto Superiore di Sanita’ , Viale Regina Elena 299, Rome, 00161, Italy Published online: 19 Nov 2008.

BIOCHRONOLOGY OF THE PLEISTOCENE MAMMAL FAUNA FROM PONTE GALERIA (ROME) AND REMARKS ON THE MIDDLE GALERIAN FAUNAS

Taking into account the fossil mammal material recently discovered at Cava di Breccia (sands outcropping at Ponte Galeria, Rome), the revised fossils from the area and the updated stratigraphical settings of the Ponte Galeria Formation (Rome), the Authors discuss the biochronology of the Middle Galerian faunal assemblages with a new definition of its Faunal Units. 1) The mammal fauna of Isernia in our opinion is strongly conditioned by palaeoenvironmental factors and by human influence. The occurrence at Isernia La Pineta of the rodent Arvicola cantiana, which was widespread in Western Europe from 0.6 MA, does not match with the biochronology of the fauna and with the absolute dating (0.736 MA). A new radiometric dating will be useful to determine the age of the Isernia La Pineta local fauna, which can be considered younger than 0.736 MA on the basis of its faunal assemblage. 2) The age of the faunal assemblage of Ponte Galeria is between 0.8 and 0.75 MA, approximately in correspondence with the Brunhes-Matuyama paleomagnetic reversal event. The first occurrence of Bos galerianus and Megaloceros savini testifies a faunal renewal in comparison with the faunal assemblage of Slivia. The megacerine cervids from Ponte Galeria are more primitive than those from Isernia La Pineta and Venosa-Notarchirico. The Ponte Galeria local fauna has to be considered as a distinct Faunal Unit, younger than Slivia F.U. and older than the Isernia La Pineta fauna. SHORT NOTE