scholarly journals Unique histological features of the tail skin of cotton rat (Sigmodon hispidus) related to caudal autotomy

Biology Open ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. bio058230
Author(s):  
Marina Hosotani ◽  
Teppei Nakamura ◽  
Osamu Ichii ◽  
Takao Irie ◽  
Yuji Sunden ◽  
...  
Keyword(s):  
Muscle Layer ◽  
Fracture Plane ◽  
Sigmodon Hispidus ◽  
Tail Regeneration ◽  
Cotton Rat ◽  
Histological Features ◽  
Laboratory Rats ◽  
Cotton Rats ◽  
Caudal Autotomy ◽  
Rat Tail

ABSTRACTCaudal autotomy in rodents is an evolutionarily acquired phenomenon enabling escape from predators, by discarding the tail skin after traumatic injuries. The histological mechanisms underlying caudal autotomy seem to differ among species. Cotton rats (Sigmodon hispidus), which are important laboratory rodents for human infectious diseases, possess a fragile tail. In this study, we compared the tail histology of cotton rats with that of laboratory rats (Rattus norvegicus), which have no fragility on their tail, to elucidate the process of rodent caudal autotomy. First, the cotton rats developed a false autotomy characterized by loss of the tail sheath with the caudal vertebrae remaining without tail regeneration. Second, we found the fracture plane was continuous from the interscale of the tail epidermis to the dermis, which was lined with an alignment of E-cadherin+ cells. Third, we found an obvious cleavage plane between the dermis and subjacent tissues of the cotton-rat tail, where the subcutis was composed of looser, finer, and fragmented collagen fibers compared with those of the rat. Additionally, the cotton-rat tail was easily torn, with minimum bleeding. The median coccygeal artery of the cotton rat had a thick smooth muscle layer, and its lumen was filled with the peeled intima with fibrin coagulation, which might be associated with reduced bleeding following caudal autotomy. Taken together, we reveal the unique histological features of the tail relating to the caudal autotomy process in the cotton rat, and provide novel insights to help clarify the rodent caudal autotomy mechanism.

Echinococcus multilocularis in the cotton rat. Asexual proliferation following the intraperitoneal inoculation of graded doses of protoscolices

1972 ◽  
Vol 50 (7) ◽  
pp. 941-946 ◽  
Author(s):  
M. E. Rau ◽  
C. E. Tanner
Keyword(s):  
Intermediate Host ◽  
Echinococcus Multilocularis ◽  
Sigmodon Hispidus ◽  
Cotton Rat ◽  
Cotton Rats ◽  
The Mean ◽  
Intraperitoneal Inoculation

One hundred and nine cotton rats (Sigmodon hispidus) were each inoculated intraperitoneally with one of seven graded doses of Echinococcus multilocularis protoscolices. As the size of the inoculating dose increased, corresponding gains in the mean total parasitic cyst weight, measured 60 days later, became progressively less pronounced until a plateau was reached which even massive inoculations failed to elevate significantly. Mean total cyst weights attained within 60 days of inoculation varied seasonally, probably reflecting changes in the susceptibility of the intermediate host. Thus, cotton rats incubating infections during September, October, or November bore significantly lighter parasite burdens than rats incubating infections between December and August. Furthermore, at least 10 times the number of protoscolices were required to consistently establish infections during the three autumn months than at any other time of the year. Corresponding variations in the total cyst weight could be induced experimentally by manipulating the host's photoperiod.

scholarly journals BIFURCACIÓN DE COLA DE Plestiodon copei (TAYLOR, 1933) (SQUAMATA: SCINCIDAE)

2020 ◽  
Vol 3 (2) ◽  
pp. 143
Author(s):  
Orlando Suárez Rodríguez
Keyword(s):  
Energetic Cost ◽  
Fracture Plane ◽  
Tail Regeneration ◽  
X Ray ◽  
Cartilage Formation ◽  
In The Wild ◽  
Caudal Autotomy

Caudal autotomy is a common defensive scape strategy from predation in lizards, this strategy can affect the fitness of the individuals associated to energetic cost caused by tail regeneration. Several records of tail anomalies have been reported in various families of lizards. In this note we reported a tail bifurcation specimen of Plestiodon copei found in the wild. An X-ray showed that the two branches are not ossified after the fracture plane in the tail, with cartilage formation in both branches instead.

scholarly journals Comparison of Ovarian Morphology and Follicular Disturbances between Two Inbred Strains of Cotton Rats (Sigmodon hispidus)

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1768
Author(s):  
Md Rashedul Islam ◽  
Osamu Ichii ◽  
Teppei Nakamura ◽  
Takao Irie ◽  
Akio Shinohara ◽  
...  
Keyword(s):  
Cell Death ◽  
Strain Differences ◽  
Inbred Strains ◽  
Ovarian Follicles ◽  
Sigmodon Hispidus ◽  
Cotton Rat ◽  
Ovarian Histology ◽  
Ovarian Morphology ◽  
Cotton Rats ◽  
Single Nucleus

Most mammalian ovarian follicles contain only a single oocyte having a single nucleus. However, two or more oocytes and nuclei are observed within one follicle and one oocyte, respectively, in several species, including cotton rat (CR, Sigmodon hispidus). The present study compared ovarian histology, focusing on folliculogenesis, between two inbred CR strains, HIS/Hiph and HIS/Mz. At 4 weeks of age, ovarian sections from both the strains were analyzed histologically. Multi-oocyte follicles (MOFs) and double-nucleated oocytes (DNOs) were observed in all stages of developing follicles in HIS/Hiph, whereas HIS/Mz had MOFs up to secondary stages and lacked DNOs. The estimated total follicles in HIS/Mz were almost half that of HIS/Hiph, but interstitial cells were well developed in HIS/Mz. Furthermore, immunostaining revealed no clear strain differences in the appearance of oocytes positive for Ki67, PCNA, and p63 in MOF or DNOs; no cell death was observed in these oocytes. Ultrastructural analysis revealed more abundant mitochondrial clouds in oocytes of HIS/Hiph than HIS/Mz. Thus, we clarified the strain differences in the CR ovary. These findings indicate that early events during folliculogenesis affect the unique ovarian phenotypes found in CRs, including MOFs or DNOs, and their strain differences.

scholarly journals The swamp rice rat (Oryzomys palustris natator) as a possible laboratory animal for special purposes

1951 ◽  
Vol 49 (4) ◽  
pp. 427-429 ◽  
Author(s):  
J. S. Steward
Keyword(s):  
Laboratory Animal ◽  
Routine Screening ◽  
Screening Tests ◽  
Sigmodon Hispidus ◽  
Cotton Rat ◽  
Weight Range ◽  
Cotton Rats ◽  
Oryzomys Palustris

The Florida cotton rat, Sigmodon hispidus, has become established as a laboratory animal largely because it is the best known host of the filariid worm, Litomosoides carinii, which is used in routine screening tests for filariacides.Cotton rats are unsuitable for infecting when very small, and as the filariae take several months to develop enough for the purpose of the test, most of the cotton rats are fully grown at the time of testing. Their weight range is 125–225 g., average about 170 g.

Diversifying animal models: the use of hispid cotton rats (Sigmodon hispidus) in infectious diseases

2002 ◽  
Vol 36 (4) ◽  
pp. 357-372 ◽  
Author(s):  
Stefan Niewiesk ◽  
Gregory Prince
Keyword(s):  
Animal Models ◽  
Infectious Diseases ◽  
Immune Responses ◽  
Laboratory Animal ◽  
State Of The Art ◽  
Immunological Methods ◽  
Sigmodon Hispidus ◽  
Cotton Rat ◽  
Specific Antibodies ◽  
Cotton Rats

The hispid cotton rat ( Sigmodon hispidus) has been a longstanding laboratory animal model of infectious diseases. In this review, the most common usage of hispid cotton rats as models of infectious diseases is discussed in detail and all organisms, which have been shown to infect cotton rats, are listed. A state of the art overview is given on handling and maintenance of hispid cotton rats as well as experimental techniques such as narcosis and blood withdrawal. Most importantly, through the development of new reagents, the hispid cotton rat can be used to study immune responses against the respective pathogen. Hispid cotton rat cytokine and chemokine genes have been sequenced and cotton rat specific antibodies and cell lines have been produced which in connection with the establishment of immunological methods should facilitate the use of hispid cotton rats as animal models in the pathogenesis of infectious diseases.

scholarly journals Efficacy of the Herpes Simplex Virus 2 (HSV-2) Glycoprotein D/AS04 Vaccine against Genital HSV-2 and HSV-1 Infection and Disease in the Cotton Rat Sigmodon hispidus Model

2015 ◽  
Vol 89 (19) ◽  
pp. 9825-9840 ◽  
Author(s):  
Marina Boukhvalova ◽  
Jamall McKay ◽  
Aissatou Mbaye ◽  
Hannah Sanford-Crane ◽  
Jorge C. G. Blanco ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Genital Herpes ◽  
Sigmodon Hispidus ◽  
Cotton Rat ◽  
Cotton Rats ◽  
Simplex Virus ◽  
Herpes Simplex Virus 2 ◽  
Genital Disease ◽  
Hsv 1

ABSTRACTSubunit vaccines based on the herpes simplex virus 2 (HSV-2) glycoprotein D (gD-2) have been the major focus of HSV-2 vaccine development for the past 2 decades. Based on the promising data generated in the guinea pig model, a formulation containing truncated gD-2, aluminum salt, and MPL (gD/AS04) advanced to clinical trials. The results of these trials, however, were unexpected, as the vaccine protected against HSV-1 infection but not against HSV-2. To address this discrepancy, we developed a Depot medroxyprogesterone acetate (DMPA)-treated cotton ratSigmodon hispidusmodel of HSV-2 and HSV-1 genital infection. The severity of HSV-1 genital herpes was less than that of HSV-2 genital herpes in cotton rats, and yet the model allowed for comparative evaluation of gD/AS04 immunogenicity and efficacy. Cotton rats were intramuscularly vaccinated using a prime boost strategy with gD/AS04 (Simplirix vaccine) or control vaccine formulation (hepatitis B vaccine FENDrix) and subsequently challenged intravaginally with HSV-2 or HSV-1. The gD/AS04 vaccine was immunogenic in cotton rats and induced serum IgG directed against gD-2 and serum HSV-2 neutralizing antibodies but failed to efficiently protect against HSV-2 disease or to decrease the HSV-2 viral load. However, gD/AS04 significantly reduced vaginal titers of HSV-1 and better protected animals against HSV-1 compared to HSV-2 genital disease. The latter finding is generally consistent with the clinical outcome of the Herpevac trial of Simplirix. Passive transfer of serum from gD/AS04-immunized cotton rats conferred stronger protection against HSV-1 genital disease. These findings suggest the need for alternative vaccine strategies and the identification of new correlates of protection.IMPORTANCEIn spite of the high health burden of genital herpes, there is still no effective intervention against the disease. The significant gap in knowledge on genital herpes pathogenesis has been further highlighted by the recent failure of GSK HSV-2 vaccine Simplirix (gD/AS04) to protect humans against HSV-2 and the surprising finding that the vaccine protected against HSV-1 genital herpes instead. In this study, we report that gD/AS04 has higher efficacy against HSV-1 compared to HSV-2 genital herpes in the novel DMPA-synchronized cotton rat model of HSV-1 and HSV-2 infection. The findings help explain the results of the Simplirix trial.

The effect of maternal mass on litter size and offspring survival in the hispid cotton rat (Sigmodon hispidus)

1995 ◽  
Vol 73 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Michael T. Campbell ◽  
Norman A. Slade
Keyword(s):  
Body Mass ◽  
Litter Size ◽  
Growing Season ◽  
Litter Production ◽  
Sigmodon Hispidus ◽  
Offspring Survival ◽  
Cotton Rat ◽  
Pregnant Females ◽  
Cotton Rats ◽  
Selection For

We tested the proposition that maternal body mass affects litter production and recruitment in the cotton rat (Sigmodon hispidus) in Kansas. We also addressed hypotheses about why cotton rats in Kansas are larger and more fecund than conspecifics in Texas. We livetrapped cotton rats on both control and food-supplemented grids. Pregnant females were briefly confined until parturition; their pups were weighed and toe-clipped, then mother and young were returned to the site of capture. Subsequent trapping revealed survival of the offspring, i.e., ability of mothers to recruit pups into the population. Heavier mothers on both sets of grids gave birth to larger, heavier litters and had more pups survive to recruitment. The percentage of pups surviving was not related to maternal mass or to pup mass, so the increased recruitment resulted primarily from heavier mothers' having more rather than heavier pups. Mothers on the supplemented grids bore larger and heavier litters than their same-mass counterparts on the control grids. Despite their larger litters, lighter (ca. 100 g) mothers on the supplemented grids recruited fewer pups than their same-mass counterparts on control grids. Because heavier female cotton rats are more fecund, our results are consistent with the hypothesis that cotton rats in Kansas are larger than in those in Texas because of selection for increased litter size in Kansas. Seasonality in Kansas restricts the number of breeding opportunities and provides a nutrient pulse that supports rapid reproduction in the growing season.

scholarly journals At What Cost? Trade-Offs and Influences on Energetic Investment in Tail Regeneration in Lizards Following Autotomy

2021 ◽  
Vol 9 (4) ◽  
pp. 53
Author(s):  
James I. Barr ◽  
Catherine A. Boisvert ◽  
Philip W. Bateman
Keyword(s):  
Environmental Factors ◽  
Future Research ◽  
Fracture Plane ◽  
Tail Regeneration ◽  
Regeneration Rate ◽  
Trade Offs ◽  
Short And Long Term ◽  
The Individual ◽  
Species Specific ◽  
Caudal Autotomy

Caudal autotomy, the ability to shed a portion of the tail, is a widespread defence strategy among lizards. Following caudal autotomy, and during regeneration, lizards face both short- and long-term costs associated with the physical loss of the tail and the energy required for regeneration. As such, the speed at which the individual regenerates its tail (regeneration rate) should reflect the fitness priorities of the individual. However, multiple factors influence the regeneration rate in lizards, making inter-specific comparisons difficult and hindering broader scale investigations. We review regeneration rates for lizards and tuatara from the published literature, discuss how species’ fitness priorities and regeneration rates are influenced by specific, life history and environmental factors, and provide recommendations for future research. Regeneration rates varied extensively (0–4.3 mm/day) across the 56 species from 14 family groups. Species-specific factors, influencing regeneration rates, varied based on the type of fracture plane, age, sex, reproductive season, and longevity. Environmental factors including temperature, photoperiod, nutrition, and stress also affected regeneration rates, as did the method of autotomy induction, and the position of the tail also influenced regeneration rates for lizards. Additionally, regeneration could alter an individual’s behaviour, growth, and reproductive output, but this varied depending on the species.

Taste Preferences in the Cotton Rat (Sigmodon Hispidus)

1977 ◽  
Vol 45 (2) ◽  
pp. 379-385 ◽  
Author(s):  
James R. Nevitt ◽  
Arthur E. Harriman
Keyword(s):  
Sex Differences ◽  
Comparative Data ◽  
Taste Preferences ◽  
Sigmodon Hispidus ◽  
Acid Solutions ◽  
Salt Solutions ◽  
Cotton Rat ◽  
Cotton Rats

This study focused on taste preferences in hispid cotton rats ( Sigmodon hispidus) as measured by 2-bottle, 48-hr. drinking tests. In a series of continuous tests, fluid intakes were recorded for 5 sugar solutions (fructose, glucose, sucrose, maltose and lactose), 3 salt solutions (KCl, MgSO4 and NaCl), and 2 acid solutions. In an attempt to supplement incomplete and divergent comparative data on rodents' taste preferences, this study investigated sugar and salt preferences at five concentrations (.005, .05, .10, .50, and 1.0 M) and acid preferences at six concentrations (4.0, 2.3, 2.0, 1.8, 1.6, and 1.5 pH). Significant differences in concentration in intake of all salts, acids and sugars were noted. Significant sex differences were observed for intakes of sucrose and NaCl at several concentrations. All sugars were preferred maximally at .10 M. The salts NaCl and KCl were preferred maximally at .005 M and MgSO4 was preferred maximally at .05 M. The role of the sugars used in the experiment was discussed in terms of incentive values and possible reinforcers for later experiments.

scholarly journals Resistance of Cotton Rats, Sigmodon hispidus, to Primary Infection by Nippostrongylus brasiliensis

2002 ◽  
Vol 64 (5) ◽  
pp. 423-426 ◽  
Author(s):  
Hendra WIBAWA ◽  
Deni NOVIANA ◽  
Kimiyuki TSUCHIYA ◽  
Fadjar SATRIJA ◽  
Yoichiro HORII
Keyword(s):  
Primary Infection ◽  
Nippostrongylus Brasiliensis ◽  
Sigmodon Hispidus ◽  
Cotton Rats
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