Xu, Meng-Meng; Wang, De-Hua
To better understand how desert rodents adapt to water scarcity, we examined urine osmolality, renal distribution and expression of aquaporins (AQPs) in Mongolian gerbils (Meriones unguiculatus) during 7 days of water deprivation (WD). Urine osmolality of the gerbils during WD averaged 7503 mOsm kg(-1). Renal distributions of AQP1, AQP2, and AQP3 were similar to that described in other rodents. After the 7 day WD, renal AQP2 was up-regulated, while resting metabolic rate and total evaporative water loss decreased by 43% and 36%, respectively. Our data demonstrated that Mongolian gerbils showed high urine concentration, renal AQPs expression and body water conservation to cope with limited water availability, which may be critical for their survival during dry seasons in cold deserts.
Mohanty, Madhu Chhanda; Ravindran, Balachandran
Meriones unguiculatus commonly known as gerbils are widely used as animal models for a variety of parasitic infections such as Brugia malayi, Entamoeba histolytica, Giardia duodenalis, Toxoplasma gondi, Helicobacter pylori, Strongyloides stercoralis and Echinococcus multilocularis. Groups of BALB/c mice, gerbils and XID mice were studied for antibody responses to T-independent antigens. Gerbils were found to be significantly deficient in eliciting antibodies to both dextran and phosphorylcholine (PC) in comparison to BALB/c mice. The antibody response of gerbils to T-independent antigens was found to be similar to the response observed in Bruton's tyrosine kinase (Btk) deficient XID mice, which are known to be poor responders to T-independent antigens. Similar to XID mice, normal gerbil sera were found to be deficient in naturally occurring antibodies to single stranded DNA (SS-DNA), lipopolysaccharide (LPS) and phospholipids. This raises the possibility of a deficiency of CD5+ B-lymphocytes (also known as B-1 cells) in gerbils, since deficiency of this sub-population of B-lymphocytes has been attributed to the absence of such naturally occurring antibodies in XID mice. These results indicate the need to study immunogenicity of parasite T-independent antigens and their relationship to protective immunity in parasitic infections in gerbils.
Williams, R. J.; Ladd, G. F.
Describes animal behavior experiments that can be easily performed by secondary school students. The experiments illustrate territorial behavior, social order, and exploratory behavior in Mongolian gerbils. (JR)
Shi, Yaolong; Wang, Dehua
Mongolian gerbils (Meriones unguiculatus) have evolved a wide thermoneutral zone (26.5-38.9 °C) and high upper critical temperature, and appear to have a high tolerance for heat exposure. Here, we use a metabolomic approach to measure global metabolite profiles for gerbils between lower (27 °C) and upper critical temperatures (38 °C) to investigate the role of metabolomic characterization in maintaining basal metabolic rates within a wide thermoneutral zone. We found that in serum and liver, 14 and 19 metabolites were significantly altered, respectively. In the aerobic respiration-related tricarboxylic cycle (TCA), 5 intermediates (isocitric acid, cis-aconitic acid, α-ketoglutaric acid, fumaric acid and malic acid) were increased in serum in 38 °C animals; however, no such increase was found in the liver. A stable level of hepatic TCA cycle intermediates may be related to the steady state of aerobic respiration at 38 °C. Metabolomic results also revealed that acute heat exposure caused increased oxidative stress and low molecular weight antioxidants in Mongolian gerbils. Increased methionine and 2-hydroxybutyrate suggest an accelerated synthesis of glutathione. Increased urate and its precursors, inosine and hypoxanthine, were detected at 38 °C. Glucuronate, threonate and oxalate involved in ascorbate synthesis and degradation were increased in serum at 38 °C. In conclusion, although dramatic metabolomic variation was found, a stable hepatic TCA cycle may contribute to maintaining a constant basal metabolic rate within a wide thermoneutral zone in Mongolian gerbils.
Agulnik, S I; Silver, L M
The classification of the African spiny mice (genus Acomys) within the Muridae family of rodents has been fraught with controversy. Morphological data suggest a close affinity between this group and true old world mice of the genus Mus. However, the combined results of immunological, biochemical, and DNA melting studies suggest that spiny mice should not even be considered as members of the Murinae subfamily. To further elucidate the position of the spiny mice within the rodent phylogenetic tree, we performed a direct sequence comparison of a 583-nucleotide homologous region from the spiny mouse type species Acomys cahirinus and five other representative rodent species. Our results provide incontrovertible evidence to support the contention that the spiny mouse is more closely related to the Mongolian gerbil Meriones unguiculatus than it is to Mus musculus.
Martínez, Ana; Ramos, Guillermo; Martínez-Torres, Martín; Nicolás, Leticia; Carmona, Agustín; Cárdenas, Mario; Luis, Juana
Here, we analyzed the effects of testosterone (T) and its metabolites, estradiol (E2) and dihydrotestosterone (DHT), on the onset of paternal behavior in virgin male Mongolian gerbils (Meriones unguiculatus). We hypothesized that T and E2, but not DHT, would facilitate the onset of paternal behavior. Seventy males displaying aggression toward pups were selected through a paternal behavior screening test. Forty males were bilaterally castrated. Of them, 10 were implanted with T, 10 with E2, and 10 with DHT, and 10 received no treatment. Another 30 males underwent a sham procedure. In these gerbils, T, E2 and DHT were measured to obtain the basal levels of these hormones. After treatment, the paternal behavior test was conducted again. Blood samples were obtained immediately after the administration of the test for the quantification of T, E2 and DHT by radioimmunoassay. Surprisingly, 100% of the males that received T, E2 and DHT implants stopped being aggressive and became paternal. Castrated and sham-operated males displayed no changes in their aggressive behaviors. This is the first report that T and its metabolites are involved in neuroendocrine mechanisms that inhibit aggression toward pups and facilitate paternal behavior in virgin male Mongolian gerbils. In addition, this is the first report of regulation of paternal behavior in a rodent by estrogenic and androgenic pathways.
Chadee, K.; Meerovitch, E.
Sequential development and pathology of experimentally induced amebic liver abscess in the gerbil (Meriones unguiculatus) were studied from 1 to 60 days after inoculation. Early lesions were characterized by an acute inflammatory response, which became granulomatous at 5 days. Early granulomas were discrete, with well-defined fibrohistiocytic walls. Trophozoite dissemination as a result of fibrolysis of granuloma wall was confined to the liver parenchyma. The granulomatous cellular infiltrate (less than 20 days) was characterized by granulocytes and histiocytes; older granulomas (greater than 30 days) were composed of lymphocytic infiltrate, plasma cells, and a few granulocytes, and were characterized by the absence of epithelioid histiocytes. The degree of pathologic change adjacent to liver granulomas followed the sequential development of the amebic liver abscess. Severe changes observed were portal canal lymphocytic infiltration, the presence of foreign body giant cells, periportal fibrosis, proliferation of bile duct epithelium, and hepatocyte anisonucleosis and ballooning degeneration. The pathogenesis of the infection and the usefulness of the gerbil model for the study of human amebiasis are discussed. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 PMID:6385727
Vikhlyantsev, I M; Okuneva, A D; Shpagina, M D; Shumilina, Yu V; Molochkov, N V; Salmov, N N; Podlubnaya, Z A
Changes in isoform composition, secondary structure, and titin phosphorylation in Mongolian gerbil (Meriones unguiculatus) cardiac muscle were studied after 12-day-long space flight onboard the Russian spacecraft Foton-M3. The effect of titin on the actin-activated myosin ATPase activity at pCa 7.5 and 4.6 was also studied. Almost twofold increase in titin long N2BA isoform content relative to that of short N2B isoform was found on electrophoregrams of cardiac muscle left ventricle of the flight group gerbils. Differences in secondary structure of titin isolated from cardiac muscle of control and flight groups of gerbils were found. An increase in phosphorylation (1.30-1.35-fold) of titin of cardiac muscle of the flight group gerbils was found. A decrease in activating effect of titin of cardiac muscle of the flight group gerbils on actomyosin ATPase activity in vitro was also found. The observed changes are discussed in the context of M. unguiculatus cardiac muscle adaptation to conditions of weightlessness.
Johnston, H S; McGadey, J; Thompson, G G; Moore, M R; Payne, A P
The Harderian gland, its secretory duct and porphyrin content were examined in the mongolian gerbil (Meriones unguiculatus). The gland consisted of tubules lined by a single layer of epithelial cells and a myoepithelial network. The tubule cells were often binucleate and possessed lipid vacuoles in the apical half of the cell, a corona of granular endoplasmic reticulum surrounding the nucleus, and cytoplasmic 'slashes'. The latter are probably derived from dense membranous couplets and may be precursors of the lipid vacuoles. Holocrine and merocrine secretion was observed. Interstitial cells included plasma cells, mast cells and (predominantly) melanocytes which render the gland black. The gland was surrounded by a collagen capsule and an outer layer of highly attenuated (possibly endothelioid) cells. Within the gland, the secretory duct was lined by a single layer of normal tubule cells. Outside the gland, the duct enlarged to form an ampulla, from which clefts led off to deep crypts. The ampulla and clefts were lined by cells with small dense apical granules and stubby microvilli; some possessed lipid vacuoles. The crypts were lined by serous cells with active Golgi regions. At the duct opening, ampullary cells became squamous and goblet cells occurred. Geometric crystalloid deposits (with a layered structure of 7.6 nm periodicity) occurred at cleft-crypt junctions. Islets of extra-glandular ductal tissue were occasionally found within the gland. Porphyrins were detectable both by chemical assay and fluorescence microscopy. There was a trend for female glands to have a higher content than males. Solid intraluminal accretions of porphyrin and/or lipid were present. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 PMID:6654750
de la Fuente, Roberto; Manterola, Marcia; Viera, Alberto; Parra, María Teresa; Alsheimer, Manfred; Rufas, Julio S; Page, Jesús
Telomeric DNA repeats are key features of chromosomes that allow the maintenance of integrity and stability in the telomeres. However, interstitial telomere sites (ITSs) can also be found along the chromosomes, especially near the centromere, where they may appear following chromosomal rearrangements like Robertsonian translocations. There is no defined role for ITSs, but they are linked to DNA damage-prone sites. We were interested in studying the structural organization of ITSs during meiosis, a kind of cell division in which programmed DNA damage events and noticeable chromatin reorganizations occur. Here we describe the presence of highly amplified ITSs in the pericentromeric region of Mongolian gerbil (Meriones unguiculatus) chromosomes. During meiosis, ITSs show a different chromatin conformation than DNA repeats at telomeres, appearing more extended and accumulating heterochromatin markers. Interestingly, ITSs also recruit the telomeric proteins RAP1 and TRF1, but in a stage-dependent manner, appearing mainly at late prophase I stages. We did not find a specific accumulation of DNA repair factors to the ITSs, such as γH2AX or RAD51 at these stages, but we could detect the presence of MLH1, a marker for reciprocal recombination. However, contrary to previous reports, we did not find a specific accumulation of crossovers at ITSs. Intriguingly, some centromeric regions of metacentric chromosomes may bind the nuclear envelope through the association to SUN1 protein, a feature usually performed by telomeres. Therefore, ITSs present a particular and dynamic chromatin configuration in meiosis, which could be involved in maintaining their genetic stability, but they additionally retain some features of distal telomeres, provided by their capability to associate to telomere-binding proteins.
Conlon, Lauren E; King, Ryan D; Moran, Nancy E; Erdman, John W
Evidence suggests that monounsaturated and polyunsaturated fats facilitate greater absorption of carotenoids than saturated fats. However, the comparison of consuming a polyunsaturated fat source versus a saturated fat source on tomato carotenoid bioaccumulation has not been examined. The goal of this study was to determine the influence of coconut oil and safflower oil on tomato carotenoid tissue accumulation in Mongolian gerbils ( Meriones unguiculatus ) fed a 20% fat diet. Coconut oil feeding increased carotenoid concentrations among many compartments including total carotenoids in the serum (p = 0.0003), adrenal glandular phytoene (p = 0.04), hepatic phytofluene (p = 0.0001), testicular all-trans-lycopene (p = 0.01), and cis-lycopene (p = 0.006) in the prostate-seminal vesicle complex compared to safflower oil. Safflower oil-fed gerbils had greater splenic lycopene concentrations (p = 0.006) compared to coconut oil-fed gerbils. Coconut oil feeding increased serum cholesterol (p = 0.0001) and decreased hepatic cholesterol (p = 0.0003) compared to safflower oil. In summary, coconut oil enhanced tissue uptake of tomato carotenoids to a greater degree than safflower oil. These results may have been due to the large proportion of medium-chain fatty acids in coconut oil, which might have caused a shift in cholesterol flux to favor extrahepatic carotenoid tissue deposition.
De Jesús-Gabino, A F; Mendoza-de Gives, P; Salinas-Sánchez, D O; López-Arellano, M E; Liébano-Hernández, E; Hernández-Velázquez, V M; Valladares-Cisneros, G
The anthelmintic effect of Prosopis laevigata (mezquite) n-hexanic extract was evaluated against Haemonchus contortus endoparasitic stages in artificially infected gerbils (Meriones unguiculatus). Prosopis laevigata leaves were collected from the Sierra de Huautla, Ecological Reserve of the Biosphere, in Morelos State, Mexico; dehydrated under shade and macerated with n-hexane for 3 days, followed by distillation for 8 h. This procedure was repeated three times and the final extract was kept at 4 degrees C. The in vivo effect of the plant extract was evaluated in gerbils artificially infected with H. contortus. Plant extract concentration was 40 mg/ml. Three groups of gerbils were as follows: group 1 (n = 7), P. laevigata extract at 100 microl intraperitoneally (IP); group 2 (n = 6), control--Tween 20 in water at a single dose of 100 microl IP; group 3 (n = 8) also served as a control, receiving water only, to determine the mortality due to causes other than the plant extract. An additional group of seven gerbils (group 4) was administered fenbendazole, as a positive control. Five days later the animals were euthanized and stomach and mucosa removed to quantify the nematodes. Data were analysed using the Student's t-test to compare the mean of nematodes obtained in groups 1, 2 and 3. The parasite population in the plant extract treated group 1 was reduced by 42.5% (P < 0.05) with respect to the control group 2; and when control group 3 was used for comparison the parasitic reduction was estimated as 53.11%. This study shows the in vivo anthelmintic effect of P. laevigata n-hexane extract for the first time, using gerbils as an in vivo model, with potential use in sheep.
Chadee, K.; Meerovitch, E.
The pathogenesis of experimentally induced cecal amebiasis in gerbils (Meriones unguiculatus) was studied from 5 to 60 days after inoculation. Ulcerative lesions were noted 10 to 60 days after inoculation. The sequential development of lesions was asynchronous and progressed from destruction of the interglandular epithelium and of glandular crypt elements to loss of mucosa and formation of granulomatous lesions in the submucosa involving the muscularis mucosae. Pathologic changes in the liver correlated with the formation of ulcerative cecal lesions. Subacute hepatic changes showed lymphocytic portal infiltrate, Kupffer cell hyperplasia, multinucleated giant cells, granuloma formation, and sinusoidal mononuclear and granulocytic infiltrates. Metastatic amebic liver abscesses occurred as early as 10 days after inoculation, and small abscesses were found in the portal areas of the right liver lobe. The sequential development and pathologic manifestation of the infection and the usefulness of the gerbil for the study of human intestinal amebiasis are discussed. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 PMID:4014436
Rehorek, Susan J; Cunningham, Jayna; Bruening, Amanda E; Johnson, Jessica L; Bhatnagar, Kunwar P; Smith, Timothy D; Hillenius, Willem J
The nasolacrimal apparatus (NLA) is a multicomponent functional system comprised of multiple orbital glands (up to four larger multicellular exocrine structures), a nasal chemosensory structure (vomeronasal organ: VNO), and a connecting duct (nasolacrimal duct: NLD). Although this system has been described in all tetrapod vertebrate lineages, albeit not always with all three main components present, considerably less is known about its ontogeny. The Mongolian gerbil (Meriones unguiculatus) is a common lab rodent in which the individual components of the adult NLA have been well studied, but as yet nothing is known about the ontogeny of the NLA. In this study, serial sections of 15 fetal and three adult Mongolian gerbil heads show that the development of the NLA falls into three fetal stages: inception (origin of all features), elongation (lengthening of all features), and expansion (widening of all features). No postnatal or juvenile specimens were observed in this study, but considerable growth evidently occurs before the final adult condition is reached. The development of the orbital glands and the VNO in the Mongolian gerbil is largely consistent with those in other mammals, despite a slight nomenclatural conundrum for the anterior orbital glands. However, the Mongolian gerbil NLD follows a more circuitous route than in other tetrapods, due mainly to the convoluted arrangement of the narial cartilages, the development of a pair of enlarged incisors as well as an enlarged infraorbital foramen. The impact of these associated features on the ontogeny and phylogeny of the NLA could be examined through the approach of network science. This approach allows for the incorporation of adaptations to specific lifestyles as potential explanations for the variation observed in the NLA across different tetrapod clades.
Chirgwin, Sharon R; Nowling, Jena M; Coleman, Sharon U; Klei, Thomas R
Infection of humans with filarial parasites has long been associated with the maintenance of a dominant Th2-type host immune response. This is reflected by increases in interleukin (IL)-4- and IL-5-producing T cells, elevated immunoglobulin (Ig)E and IgG4 levels, and a pronounced eosinophilia. The Mongolian gerbil (Meriones unguiculatus) is permissive for the filarial nematodes Brugia malayi and B. pahangi. As in humans, persistent microfilaremic infections of gerbils with Brugia spp. results in increases in Th2 cytokines such as IL-4 and IL-5. The association of dominant Th2 cytokine profiles with the maintenance of infection suggests that the introduction of Brugia spp. into a strongly Th1-biased environment may adversely affect parasite establishment. Indeed, studies conducted in mice with B. malayi suggest that depleting Th1 effectors such as interferon (IFN)-gamma and nitric oxide results in increased worm recoveries. In the present studies, the Mongolian gerbil was used as a model to investigate the effect of a dominant Th1 cytokine environment on the establishment of B. pahangi. Intraperitoneal (i.p.) administration of immunostimulatory oligodeoxynucleotide (IS ODN) induced the production of IFN-gamma in the peritoneal exudate cells and spleen of gerbils. The presence of IFN-gamma at the time of B. pahangi infection did result in an altered host immune response to B. pahangi. Gerbils that received IS ODN before i.p. B. pahangi infections showed lower levels of the Th2-type cytokines IL-4 and IL-5, compared with animals that received B. pahangi alone (0 + Bp). This alteration in cytokine profile, however, did not alter the establishment or development of B. pahangi in the peritoneal cavity. Furthermore, there was no difference in the granulomatous response of gerbils to soluble adult B. pahangi antigen bound to beads embolized in their lungs, regardless of treatment group, suggesting that IL-4 and IL-5 are not essential contributors to the systemic host
Juana, Luis; Bárbara, Vázquez-Gaytán; Martín, Martínez-Torres; Agustín, Carmona; Guillermo, Ramos-Blancas; Guadalupe, Ortíz
The first studies that correlated mammalian paternal behavior and testosterone levels indicated that the concentration of this steroid hormone decreases when males exhibit paternal care. However, recent studies have also shown that testosterone levels do not decrease when males display paternal behavior. In this study, we measured testosterone levels in plasma throughout the reproductive cycle of the Mongolian gerbil. Testosterone concentrations were correlated with paternal care as well as aggression. We also examined whether there is a trade-off between paternal behavior and aggression in this mammal. Our results show that Mongolian gerbil testosterone levels do not decrease when the males give paternal care. Likewise, male Mongolian gerbils exhibit high levels of aggression while displaying paternal behavior, indicating that there is no trade-off between aggression and paternal behavior. More studies are needed to determine whether testosterone is involved in the regulation of paternal behavior in this rodent.
Argüello-García, R; Ortega-Pierres, M G
In this work, we have analyzed the humoral immune response in Mongolian gerbils infected with Giardia duodenalis trophozoites of strains P-1 and WB. The course of infection in the animals was assessed by monitoring cyst shedding in feces, and serum samples were collected at weekly intervals to measure antibody levels by ELISA. Parallel studies were carried out to determine the patterns of total and surface antigens of the parasite recognized by antibodies using Western blot and radioimmunoprecipitation (RIP) assays with the use of homospecific enzyme conjugates. Typical patterns of cyst shedding were observed in the infected animals and cyst numbers per gram of feces were consistently higher in gerbils infected with WB strain. Antibody levels to G. duodenalis antigens were observed by week 2 post-infection and were still detectable 4 months after infection. G. duodenalis antigens showed a complex but quantitatively and qualitatively different recognition pattern by infection-induced antibodies in Western blot assays which related to infecting strain. However, RIP assays showed a more restricted and common pattern of recognition of surface antigens from either strain. Taken together, the data obtained in this study provides further information regarding direct comparisons among infecting strain, patterns of infectivity, and host immune response toward G. duodenalis antigens in the gerbil model.
Kai, O; Sakemi, K; Suzuki, Y; Sonoda, Y; Imai, K
Effects of age at first-pairing on the reproductive performance of the gerbil were studied throughout the reproductive life. Six groups of 7-30 female gerbils were paired monogamously with males at different ages. Out of 101 pairs in 6 groups, 79 (78.2%) produced 1 or more litters. The mean litter size at birth and mean weaning rate of 846 litters were 4.4 (totally 3,733 pups) and 67.4% (2,517 pups), respectively. Reproduction was compared in the 6 age groups. The littering rate (No. of females with litters/No. of female paired) was significantly lower in two groups in which mature females were paired with age-matched males (Group 4) or the oldest females with younger, sexually mature males (Group 6). The interval from pairing to the first litter was shortest in two groups in which mature females were paired with one month older, sexually mature males (Groups 3 and 5). Although the oldest pairs (Group 6) produced about 7 litters, the pairs from the other 5 groups produced about 10 or more litters throughout their reproductive life. The weaning rate was significantly higher in Group 6 (the oldest pairs) than in the younger groups. The effects of parity on reproduction were estimated from the data for the 61 pairs which produced more than 8 litters in the 6 groups. The number of pups at birth and the weaning rate were decreased in last 20-30% of the total parity in all 6 groups, although the age at the last litter in all groups was significantly different. The data suggest that any decline in reproduction may be due to not age but parity in the Mongolian gerbil.
Ilyin, E. A.; Smirnov, I. A.; Soldatov, P. E.; Guryeva, T. S.; Mednikova, E. I.
A successful experiment with 12 Mongolian gerbils was performed during the 12-day flight of Russian automatic spacecraft Foton-M3 (September 14-26, 2007). Foton-M3 was not equipped with an air supply system. Due to this, a self-contained "CONTOUR" module equipped with its own Life-Support System, was developed. The cage for animals was equipped with yellow LEDs. The day/night cycle was 12:12 hours. In addition, the module was equipped with a digital video recorder located on the outside surface in front of a transparent window. In space flight, the animals were provided with food bars made of natural products and contained about 20% of water. This moisture met gerbils requirements in water; therefore, the module was not equipped with a water supply system. In the module, the environmental parameters were as follows: p02 = 143-156 (mean 150) mm Hg, pC02 - not more than 0.76 (mean 0.64) mm Hg, temperature = 23-28 (mean 26.7) °C, and RH = 29% at the beginning and 57% at the end of flight (mean 39%). Throughout the entire flight video recording of the animals was performed continuously during the daytime.
Ren, Chaoran; Pu, Mingliang; Cui, Qi; So, Kwok-Fai
In this study we investigated the morphological features of the caudal periaqueductal gray (cPAG)-projecting retinal ganglion cells (RGCs) in Mongolian gerbils using retrograde labeling, in vitro intracellular injection, confocal microscopy and three-dimensional reconstruction approaches. cPAG-projecting RGCs exhibit small somata (10–17 µm) and irregular dendritic fields (201–298 µm). Sizes of somata and dendritic fields do not show obvious variation at different distance from the optic disk (eccentricity). Dendrites are moderately branched. Morphological analysis (n = 23) reveals that cPAG-projecting RGCs ramified in sublamina a and b in the inner plexiform layer. These cells exhibit different stratification patterns based on the thickness of dendritic bands in sublaminas a and b: majority of analyzed cells (16 out of 23) have two bands of arborizations share similar thickness. The rest of analyzed cells (7 out of 23) exhibit thinner band in sublamina a than in sublamina b. Together, the present study suggests that cPAG of Mongolian gerbil could receive direct retinal inputs from two types of bistratified RGCs. Furthermore, a small subset of melanopsin-expressing RGCs (total 41 in 6 animals) is shown to innervate the rostral PAG (rPAG). Functional characteristics of these non-visual center projecting RGCs remain to be determined. PMID:25054882
Yang, Hui-Di; Wang, Qian; Wang, De-Hua
This article is part of a Special Issue "Energy Balance". Effects of γ-aminobutyric acid (GABA) on food hoarding are unknown in rodents, and the effects of energy balance and GABA have not been evaluated in females. To evaluate the role of food deprivation and GABA on food hoarding, female Mongolian gerbils were given i.p. injection of diazepam (1mg/kg and 3mg/kg, respectively), a GABAA receptor agonist. Among food-deprived females, there was a bimodal pattern in the frequency of gerbils with different levels of food hoarding. High food hoarding (HFH) and low food hoarding (LFH) gerbils were analyzed. Diazepam blocked food deprivation-induced food hoarding in HFH gerbils, but not in LFH gerbils. This blockade was associated with increased cellular activation in selected brain areas, such as the nucleus accumbens (NAcc), caudate putamen (CP) and ventral tegmental area (VTA), which suggested that direct activation of GABA in the brain reward circuitry decreased food hoarding in HFH females. Moreover, diazepam increased Fos expression in field CA2 and CA3 of the hippocampus, but had no significant effect on Fos expression in field CA1 and dentate gyrus (DG) of the hippocampus, indicating that the hippocampus has area-specific effects on food hoarding in HFH gerbils. Diazepam did not alter food intake in both HFH and LFH gerbils. In addition, serum corticosterone concentrations were higher in the HFH than in the LFH ones. Together, these data indicated that food deprivation increased food hoarding in female gerbils, diazepam reduced food deprivation-induced food hoarding in HFH gerbils, and that GABA might influence food hoarding via classical reward circuitry via the mesolimbic dopamine system and specific hippocampal areas.
Fenton, Heather; Forzán, María J.; Desmarchelier, Marion; Woodland, Meghan; Sayi, Soraya; Gilroy, Cornelia V.
A 3-year-old female gerbil developed a non-healing skin wound due to a malignant neoplasm. Histology, immunohistochemistry (cytokeratin 19 positive; vimentin, estrogen, and progesterone receptor negative), and electron microscopy (no desmosomes or melanosomes) revealed an undifferentiated carcinoma with pulmonary metastasis. Unlike in previous reports, it did not arise from the abdominal pad’s sebaceous gland. PMID:26740704
Early experience and domestication affect auditory discrimination learning, open field behaviour and brain size in wild Mongolian gerbils and domesticated laboratory gerbils (Meriones unguiculatus forma domestica).
Stuermer, Ingo W; Wetzel, Wolfram
The influence of early experience and strain differences on auditory discrimination learning, open field behaviour and brain size was investigated in wild-type Mongolian gerbils (strain Ugoe:MU95) raised in the wild (wild F-0) or in the laboratory (wild F-1) and in domesticated Laboratory Gerbils (LAB). Adult males were conditioned for 10 days in a shuttle box go/no-go paradigm to discriminate two frequency-modulated tones. Significant learning was established within 5 days in wild F-0 and within 3 days in wild F-1 and LAB. Spontaneous jumps in the shuttle box (inter-trial crossings) were frequently seen in wild F-0 and F-1, but rarely in LAB. All groups exhibited nearly the same ability to remember after 2 weeks without training. In the open field test applied on 5 consecutive days, no differences in locomotion patterns and inner field preferences were found. Rearing frequency decreased over 5 days in wild gerbils. Running distances (4-6m/min) were similar in wild F-0 and LAB, but higher in wild F-1. The ratio of brain size to body weight did not differ between wild F-0 and F-1, but was 17.1% lower in LAB. Correspondingly high brain weights in wild F-1 and F-0 support our domestication hypothesis and negate any serious effect of early experience or captivity on brain size in Mongolian gerbils. In contrast, wild F-1 raised in the laboratory show a rapid improvement in learning performance, indicating that early experience rather that genetic differences between strains affect shuttle box discrimination learning in gerbils.
Infection with CagA-Positive Helicobacter Pylori Strain Containing Three EPIYA C Phosphorylation Sites is Associated with More Severe Gastric Lesions in Experimentally Infected Mongolian Gerbils (Meriones Unguiculatus)
Junior, M. Ferreira; Batista, S.A.; Vidigal, P.V.T; Cordeiro, A.A.C.; Oliveira, F.M.S.; Prata, L.O.; Diniz, A.E.T.; Barral, C.M.; Barbuto, R.C.; Comes, A.D.; Araujo, I.D.; Queiroz, D.M.M.; Caliari, M.V.
Infection with Helicobacter pylori strains containing high number of EPIYA-C phosphorylation sites in the CagA is associated with significant gastritis and increased risk of developing pre-malignant gastric lesions and gastric carcinoma. However, these findings have not been reproduced in animal models yet. Therefore, we investigated the effect on the gastric mucosa of Mongolian gerbil (Meriones unguiculatus) infected with CagA-positive H. pylori strains exhibiting one or three EPIYA-C phosphorilation sites. Mongolian gerbils were inoculated with H. pylori clonal isolates containing one or three EPIYA-C phosphorylation sites. Control group was composed by uninfected animals challenged with Brucella broth alone. Gastric fragments were evaluated by the modified Sydney System and digital morphometry. Clonal relatedness between the isolates was considered by the identical RAPD-PCR profiles and sequencing of five housekeeping genes, vacA i/d region and of oipA. The other virulence markers were present in both isolates (vacA s1i1d1m1, iceA2, and intact dupA). CagA of both isolates was translocated and phosphorylated in AGS cells. After 45 days of infection, there was a significant increase in the number of inflammatory cells and in the area of the lamina propria in the infected animals, notably in those infected by the CagA-positive strain with three EPIYA-C phosphorylation sites. After six months of infection, a high number of EPIYA-C phosphorylation sites was associated with progressive increase in the intensity of gastritis and in the area of the lamina propria. Atrophy, intestinal metaplasia, and dysplasia were also observed more frequently in animals infected with the CagA-positive isolate with three EPIYA-C sites. We conclude that infection with H. pylori strain carrying a high number of CagA EPIYA-C phosphorylation sites is associated with more severe gastric lesions in an animal model of H. pylori infection. PMID:26150158
Xia, Yong; Qian, Lei; Yang, Zhang-Nv; Xie, Rong-Hui; Sun, Yi-Sheng; Lu, Hang-Jing; Miao, Zi-Ping; Li, Chan; Li, Xiao; Liang, Wei-Feng; Huang, Xiao-Xiao; Xia, Shi-Chang; Chen, Zhi-Ping; Jiang, Jian-Min; Zhang, Yan-Jun; Mei, Ling-Ling; Liu, She-Lan; Gu, Hua; Xu, Zhi-Yao; Fu, Xiao-Fei; Zhu, Zhi-Yong; Zhu, Han-Ping
Neurogenic pulmonary edema caused by severe brainstem encephalitis is the leading cause of death in young children infected by Enterovirus 71 (EV71). However, no pulmonary lesions have been found in EV71-infected transgenic or non-transgenic mouse models. Development of a suitable animal model is important for studying EV71 pathogenesis and assessing effect of therapeutic approaches. We had found neurological disorders in EV71-induced young gerbils previously. Here, we report severe pulmonary lesions characterized with pulmonary congestion and hemorrhage in a gerbil model for EV71 infection. In the EV71-infected gerbils, six 21-day-old or younger gerbils presented with a sudden onset of symptoms and rapid illness progression after inoculation with 1×105.5 TCID50 of EV71 via intraperitoneal (IP) or intramuscular (IM) route. Respiratory symptoms were observed along with interstitial pneumonia, pulmonary congestion and extensive lung hemorrhage could be detected in the lung tissues by histopathological examination. EV71 viral titer was found to be peak at late stages of infection. EV71-induced pulmonary lesions, together with severe neurological disorders were also observed in gerbils, accurately mimicking the disease process in EV71-infected patients. Passive transfer with immune sera from EV71 infected adult gerbils with a neutralizing antibody (GMT=89) prevented severe pulmonary lesion formation after lethal EV71 challenge. These results establish this gerbil model as a useful platform for studying the pathogenesis of EV71-induced pulmonary lesions, immunotherapy and antiviral drugs. PMID:25767882
Experimental infection of Haemonchus contortus strains resistant and susceptible to benzimidazoles and the effect on mast cells distribution in the stomach of Mongolian gerbils (Meriones unguiculatus).
Königová, Alzbeta; Hrckova, Gabriela; Velebný, Samuel; Corba, Július; Várady, Marián
Establishment rate of Haemonchus contortus in non-suppressed and immunosuppressed gerbils within 14 days post-infection was compared after inoculation with 1,000 third-stage larvae (L3), exsheathed BZ-susceptible larvae. Based on significantly higher number of larvae in gerbils receiving low doses of immunosuppressant agent hydrocortisone, development of benzimidazole (BZ)-susceptible and BZ-resistant strain of nematode in the stomach was studied on days 4, 7, 10, and 14 p.i. Sections of stomach from both groups of animals were examined for overall histopathological response and dynamics of mucosal mast cells (MMC) and connective tissue mast cells (CTMC). In the immunosuppressed gerbils, H. contortus L3 stage larvae developed to the L4 stage on days 10 and 14 p.i., and their sex ratio was higher toward female worms. Significantly higher ratios of establishment rate were recorded for BZ-susceptible than BZ-resistant strain. Infection elicited strong inflammation mainly in the lamina propria mucosae, where MMC numbers peaked on day 7 p.i., being present in a significantly higher numbers in gerbils infected with BZ-susceptible strain. Infection with BZ-susceptible strain of nematode also resulted in a higher number of CTMC in comparison with the effect of BZ-resistant strain, which were observed in the tela submucosa only. Thus, H. contortus infection in gerbils seems to be a suitable model to study host-parasite interactions. Our results indicate that BZ-resistant strain of H. contortus have a decreased capacity to establish infection in direct relation with lower mucosal and connective tissue MCs counts in the stomach.
Zipperer, Ginger R; Arumugam, Sridhar; Chirgwin, Sharon R; Coleman, Sharon U; Shakya, Krishna P; Klei, Thomas R
Previous studies have shown that intradermally (ID) injected Brugia pahangi L3 s migrate through various tissues and into the lymphatics of gerbils in a distinct pattern. Excretory/secretory products (ES) produced at the time of invasion of B. pahangi are likely to be important in this early migration phase of the parasite life cycle in their rodent host. Hence, early L3 ES was collected from 24h in vitro cultures of B. pahangi L3 larvae and used in immunization experiments to investigate the effect of immunity to early L3 ES on worm migration, survival and development of B. pahangi. Immunization of gerbils with ES in RIBI adjuvant produced antibodies to numerous ES proteins eliciting a strong humoral response to ES and indirect fluorescent antibody (IFA) assay using anti-ES serum recognized the ES proteins on the surface of B. pahangi L3 larvae. Following ES immunization, gerbils were challenged either ID or intraperitoneally (IP) with 100 L3 s of B. pahangi and euthanized at 3 or 106 days post inoculation (DPI). Immunization with early ES slowed the migration of ID inoculated L3 at 3 DPI and significantly altered the locations of adult worms at 106 DPI. Immunization did not induce protection in any treatment group. However, immunized animals had significantly fewer microfilariae per female worm suggesting the antigens in ES are important in microfilariae development or survival in the host. The number of lymphatic granulomas was also significantly reduced in ES immunized animals. It is important to note that microfilariae serve as a nidus in these granulomas. Our results shows immunization with early Brugia malayi L3 ES alters the worm migration, affects circulating microfilarial numbers and reduces lymphatic granulomas associated with B. pahangi infection in gerbils.
Ejoh, Richard A; Dever, Joseph T; Mills, Jordan P; Tanumihardjo, Sherry A
Leafy vegetables are important sources of provitamin A carotenoids. Information on their ability to provide vitamin A is often misleading because of the methodology used to assess bioefficacy. Mongolian gerbils were used to evaluate the bioefficacy of provitamin A carotenoids in tropical leafy vegetables (i.e. Solanum nigrum, Moringa oleifera, Vernonia calvoana and Hibiscus cannabinus) that are indigenous to Africa. Gerbils (n 67) were vitamin A-depleted for 5 weeks. After a baseline kill (n 7), the gerbils were weight-matched and assigned to six treatment groups (n 10; four vegetable groups; negative and positive controls). For 4 weeks, the treatments included 35 nmol vitamin A (theoretical concentrations based on 100 % bioefficacy) in the form of vegetables or retinyl acetate. In addition to their diets, the control and vegetable groups received daily doses of oil, while the vitamin A group received retinyl acetate in oil matched to prior day intake. Serum and livers were analysed for vitamin A using HPLC. Serum retinol concentrations did not differ among groups, but total liver vitamin A of the vitamin A and vegetable groups were higher than that of the negative control group (P < 0.0001). Liver beta-carotene 15,15'-monooxygenase-1 expression levels were determined for two vegetable groups and were similar to the positive and negative controls. Conversion factors for the different leafy vegetables were between 1.9 and 2.3 microg beta-carotene equivalents to 1 microg retinol. Small quantities of these vegetables maintained vitamin A status in gerbils through efficient bioconversion of beta-carotene to retinol.
Bresnahan, Kara A; Davis, Christopher R; Tanumihardjo, Sherry A
Provitamin A biofortification of staple crops may decrease the prevalence of vitamin A (VA) deficiency if widely adopted in target countries. To assess the impact of processing methods on the VA value of plant foods, the unique bioefficacies of cis-βC isomers (formed during cooking) compared with all-trans (at) β-carotene (βC) must be determined. The bioefficacies of 9-cis (9c)- and 13-cis (13c)-βC isomers were compared with those of the at-βC isomer and VA positive (VA+) and negative (VA - ) controls in VA-depleted Mongolian gerbils (Meriones unguiculatus) in two experimental studies (study 1, n 56; study 2, n 57). A 3- or 4-week depletion period was followed by a 3- or 4-week treatment period in which the groups received oral doses of the 9c-, 13c- or at-βC isomers in cottonseed oil (study 1, 15 nmol/d; study 2, 30 nmol/d). In study 1, the βC isomers did not maintain baseline liver VA stores in all groups (0.69 (SD 0.20) μmol/liver) except in the VA+group (0.56 (SD 0.10) μmol/liver) (P= 0.0026). The βC groups were similar to the VA+group, but the 9c- and 13c-βC groups did not differ from the VA - group (0.39 (SD 0.09) μmol/liver). In study 2, the βC isomers maintained baseline liver VA stores in all the βC groups (0.35 (SD 0.13) μmol/liver), and in the VA+group, the VA supplement (0.54 (SD 0.19) μmol/liver) exceeded the baseline VA status (0.38 (SD 0.15) μmol/liver) (P< 0.0001); however, the 9c-βC group did not differ from the VA - group (0.20 (SD 0.07) μmol/liver). In vivo isomerisation of βC was confirmed in both experimental studies. Lower VA bioconversion factor values were obtained for the cis-βC isomers in study 2 when compared with study 1, but higher values were obtained for the at-βC isomer. Dose and VA status clearly affect bioconversion factors. In conclusion, the cis-βC isomers yielded similar liver VA stores to the at-βC isomer in Mongolian gerbils, and liver VA stores of the 9c- and 13c-βC groups did not differ when the
Ventura, Luciana L.A.; Fortes, Nathália C.L.; Santiago, Helton C.; Caliari, Marcelo V.; Gomes, Maria A.
Background Nowadays, the number of obese people in the world has reached alarming proportions. During the expansion of adipose tissue, a number of functions such as activation and release of cytokines and hormones may be affected. This leads the body to a pro-inflammatory pattern, which may affect the proper functioning of many tissues. Thus, studying the mechanisms by which obesity induces physiological disorders is necessary, and may be facilitated by the use of animal models, in particular rodents. We sought to characterize the metabolic and adipose tissue changes resulting from a diet rich in fats and simple sugars in gerbils. Methods We divided 14 gerbils into two experimental groups that received a diet rich in simple carbohydrates and fats with 5,86 kcal/g (OB, n = 7) or a standard diet with 4.15 kcal/g (CT; n = 7) for 11 weeks. The animals had free access to water and food. The animal weight and food consumption were measured weekly. Blood, adipose tissue and liver of each animal were collected at the end of experiment. The following parameters were determined: cholesterol (COL), triglycerides (TGL) and glycemia (GLI) in the plasma; cytokines (IL-6, IL-10 and TNF-α) and hormones (adiponectin and leptin) in adipose tissue; activity of superoxide dismutase (SOD) and catalase (CAT), extraction and differentiation of fat and histology in liver. Results The consumption of a diet rich in simple carbohydrates and fats led to increased total body weight and increased relative weights of liver and adipose tissue. In addition, we observed increased fasting glucose levels and circulating triglycerides, along with high TNF-α production in adipose tissue and increased total fat, cholesterol and triglyceride contents in the liver, contributing to higher intensity of hepatic steatosis. On the other hand, the animals of this group showed depletion in the enzyme activity of SOD and CAT in the liver, as well as reduction of IL-10 and adiponectin levels in adipose
Neufeld, Janina; Teuchert-Noodt, Gertraud; Grafen, Keren; Winter, York; Witte, A. Veronica
Still little is known about naturally occurring synaptogenesis in the adult neocortex and related impacts of epigenetic influences. We therefore investigated (pre)synaptic plasticity in various cortices of adult rodents, visualized by secondary lysosome accumulations (LA) in remodeling axon terminals. Twenty-two male gerbils from either enriched (ER) or impoverished rearing (IR) were used for quantification of silver-stained LA. ER-animals showed rather low LA densities in most primary fields, whereas barrel and secondary/associative cortices exhibited higher densities and layer-specific differences. In IR-animals, these differences were evened out or even inverted. Basic plastic capacities might be linked with remodeling of local intrinsic circuits in the context of cortical map adaptation in both IR- and ER-animals. Frequently described disturbances due to IR in multiple corticocortical and extracortical afferent systems, including the mesocortical dopamine projection, might have led to maladaptations in the plastic capacities of prefronto-limbic areas, as indicated by different LA densities in IR- compared with ER-animals. PMID:19809517
Schmaelzle, Samantha; Gannon, Bryan; Crawford, Serra; Arscott, Sara A.; Goltz, Shellen; Palacios-Rojas, Natalia; Pixley, Kevin V.; Simon, Philipp W.; Tanumihardjo, Sherry A.
Biofortification to increase provitamin A carotenoids is an agronomic approach to alleviate vitamin A deficiency. Two studies compared biofortified foods using in vitro and in vivo methods. Study 1 screened maize genotypes (n = 44) using in vitro analysis, which demonstrated decreasing micellarization with increasing provitamin A. Thereafter, seven 50% biofortified maize feeds that hypothesized a one-to-one equivalency between β-cryptoxanthin and β-carotene were fed to Mongolian gerbils. Total liver retinol differed among the maize groups (P = 0.0043). Study 2 assessed provitamin A bioefficacy from 0.5% high-carotene carrots added to 60% staple-food feeds, followed by in vitro screening. Liver retinol was highest in the potato and banana groups, maize group retinol did not differ from baseline, and all treatments differed from control (P < 0.0001). In conclusion, β-cryptoxanthin and β-carotene have similar bioefficacy; meal matrix effects influence provitamin A absorption from carrot; and in vitro micellarization does not predict bioefficacy. PMID:24341827
Immunization with a tetramer derivative of an anti-inflammatory pentapeptide produced by Entamoeba histolytica protects gerbils (Meriones unguiculatus) against experimental amoebic abscess of the liver.
Giménez-Scherer, Juan Antonio; Cárdenas, Guadalupe; López-Osuna, Martha; Velázquez, Juan Raymundo; Rico, Guadalupe; Isibasi, Armando; Maldonado, María del Carmen; Morales, María Esther; Fernández-Diez, Jorge; Kretschmer, Roberto R
Axenically grown Entamoeba histolytica produces a pentapeptide (Met-Gln-Cys-Asn-Ser) with several anti-inflammatory properties, including the inhibition of human monocyte locomotion (Monocyte Locomotion Inhibitory Factor (MLIF)). A construct displays the same effects as the native material. It remains to be seen if MLIF is used, or even produced in vivo by the tissue-invading parasite. If MLIF were to be relevant in invasive amoebiasis, immunizing against it could diminish this parasite advantage and prevent lesions. KLH-linked MLIF mixed with Freund's adjuvant was too aggressive an immunizing material to answer this question. However, immunization with a tetramer of MLIF (but not a scrambled version of MLIF) around a lysine core (MLIF-MAPS), that displays increased antigenicity, yet lacks excessive innate immunity activation, completely protects gerbils against amoebic abscess of the liver caused by the intraportal injection of virulent E. histolytica. Liver abscesses caused by Listeria monocytogenes were not prevented. Invasive E. histolytica may produce the parent protein of MLIF in vivo, and if appropriately cleaved, it may play a role in invasive amoebiasis. MLIF may join new vaccination strategies against amoebiasis.
Bazwinsky, I; Härtig, W; Rübsamen, R
Antibodies directed against calcium-binding proteins (CaBPs) parvalbumin, calbindin-D28k and calretinin were used as neuronal markers to identify and characterize different principal cell types in the mammalian cochlear nucleus. For this purpose, double immunofluorescence labeling and the combination of CaBP-labeling with pan-neuronal markers were applied to analyze the CaBPs distribution in neurons of the cochlear nucleus (CN) of the Mongolian gerbil (Meriones unguiculatus) and the gray short-tailed opossum (Monodelphis domestica). Despite of the fact, that these two mammalian species are not closely related, principal cell types in the CN of the two species showed many corresponding morphological features and similarities in immunolabeling of the CaBPs. Parvalbumin seems not to be suited as a differential neuronal marker in the CN since it is expressed by almost all neurons. In contrast, calbindin and calretinin were more restricted to specific cell types and showed a mostly complementary labeling pattern. As one of the most interesting findings, calbindin and calretinin were predominantly found in subpopulations of globular bushy cells and octopus cells in the ventral CN. Such a neuron-specific CaBP-expression in subpopulations of morphologically defined cell types argues for a more refined classification of CN cell types in Meriones and Monodelphis. Additionally, other cell types (cartwheel cells, unipolar brush cells, fusiform cells) were marked with calbindin or calretinin as well. Calretinin staining was predominantly observed in auditory nerve fibers and their endings including endbulbs of Held in Meriones. Spherical bushy cells showed a different calretinin-immunolabeling in Meriones and Monodelphis. This species-specific difference may be related to adaptive differences in auditory function.
Vianna, Gustavo José Caldas; de Melo, Alan Lane
A mouse-derived strain of Rodentolepis ( = Hymenolepis) nana was transferred to the Mongolian jird Meriones unguiculatus. It was found that M. unguiculatus has low susceptibility to R. nana mouse isolates. Likewise, adaptation of the parasite to jird hosts, in the absence of dexamethasone treatment, was not demonstrable, at least during ten-passage trials. Nevertheless, the parasite was able to establish, grow and develop to gravid adults in M. unguiculatus treated daily with dexamethasone. Prepatent periods in dexamethasone-treated jirds in ten-passage series ranged from 10 to 17 days post-infection (DPI), the average being 12 days, and the patent periods lasted from 18 to 30 DPI, with an average of 25 days. The population pattern of faecal egg output in immunosuppressed jirds suggests that under a daily dexamethasone treatment protocol, the parasite is able to maintain egg production as long as treatment is sustained.
Zhuang, Dafang; Du, Haiwen; Wang, Yong; Jiang, Xiaosan; Shi, Xianming; Yan, Dong
The nest flea index of Meriones unguiculatus is a critical indicator for the prevention and control of plague, which can be used not only to detect the spatial and temporal distributions of Meriones unguiculatus, but also to reveal its cluster rule. This study used global spatial autocorrelation and spatial hot spot detection methods to describe the relationship between different years and the autocorrelation coefficient of nest flea indexes; it also used a spatial detection method and GIS technology to detect the spatial gathered hot spot of Meriones unguiculatus in the epidemic areas. The results of this study showed that (1) there were statistically significant spatial autocorrelations in the nest flea indexes in 2006, 2012, 2013 and 2014. (2) Most of the distribution patterns of Meriones unguiculatus were statistically significant clusters of high values. (3) There were some typical hot spot regions of plague distributed along the Inner Mongolia plateau, north of China. (4) The hot spot regions of plague were gradually stabilized after increasing and decreasing repeatedly. Generally speaking, the number of hot spot regions showed an accelerated increase from 2005 to 2007, decreased slowly from 2007 to 2008, rapidly increased again after decreasing slowly from 2008 to 2010, showed an accelerated decrease from 2010 to 2011, and ultimately were stabilized after rapidly increasing again from 2011 to 2014. (5) The migration period of the hot spot regions was 2-3 years. The epidemic area of plague moved from southwest to east during 2005, 2007, 2008 and 2010, from east to southwest during 2007 and 2008, from east to west during 2010 and 2011, and from Midwest to east during 2011 and 2014. (6) Effective factors, such as temperature, rainfall, DEM, host density, and NDVI, can affect the spatial cluster of Meriones unguiculatus. The results of this study have important implications for exploring the temporal and spatial distribution law and distribution of the hot spot
Vaccination with a genetically modified Brugia malayi cysteine protease inhibitor-2 reduces adult parasite numbers and affects the fertility of female worms following a subcutaneous challenge of Mongolian gerbils (Meriones unguiculatus) with B. malayi infective larvae.
Arumugam, Sridhar; Wei, Junfei; Ward, Danielle; Abraham, David; Lustigman, Sara; Zhan, Bin; Klei, Thomas R
Vaccination of Mongolian gerbils with Brugia malayi cysteine protease inhibitor-2 in which the amino acid Asn66 was mutated to Lys66 (Bm-CPI-2M) resulted in reduced parasite numbers of 48.6% and 48.0% at 42 and 90 days p.i. with B. malayi L3s. Fertility of female worms was also affected at 90 days p.i. In vitro killing of L3s observed in the presence of gerbil peritoneal exudate cells and anti-Bm-CPI-2M sera suggests antibody-dependent cell-mediated cytotoxicity as a putative protective mechanism. These observations suggest that Bm-CPI-2M is a promising prophylactic and anti-fecundity vaccine candidate.
Poulaert, Marie; Gunata, Ziya; During, Alexandrine; Reboul, Emmanuelle; Laurent, Caroline; Gaillet, Sylvie; Dhuique-Mayer, Claudie
β,β-Carotene 15-15' mono-oxygenase 1 (BCMO1) is a key enzyme in vitamin A (VitA) metabolism in mammals. Dietary compounds, such as carotenoids and polyphenols, were reported to influence BCMO1 activity. The aim of this study was to evaluate the effect of hesperidin (Hes), on the VitA bioefficacy of β-carotene (Bc) from orange-fleshed sweet potato, using Mongolian gerbils, focussing on BCMO1 activity. Gerbils (n=50) depleted in VitA were divided into five groups fed with basal diet containing 3% white- or orange-fleshed sweet potatoes supplemented or not with Hes. Liver BCMO1 activity was low, with no significant differences between groups. Interestingly, intestinal mucosal BCMO1 activity was significantly higher in the gerbils fed without Bc or VitA than those fed with a VitA/Bc-supplemented diet. Finally, our results show that, under a low VitA status, Hes dramatically stimulated intestinal BCMO1 activity, an effect that could possibly be related to its action as an agonist of PPARγ.
Bazwinsky-Wutschke, I; Härtig, W; Kretzschmar, R; Rübsamen, R
In mammals, the superior olivary complex (SOC) of the brainstem is composed of nuclei that integrate afferent auditory originating from both ears. Here, the expression of different calcium-binding proteins in subnuclei of the SOC was studied in distantly related mammals, the Mongolian gerbil (Meriones unguiculatus) and the gray short-tailed opossum (Monodelphis domestica) to get a better understanding of the basal nuclear organization of the SOC. Combined immunofluorescence labeling of the calcium-binding proteins (CaBPs) parvalbumin, calbindin-D28k, and calretinin as well as pan-neuronal markers displayed characteristic distribution patterns highlighting details of neuronal architecture of SOC nuclei. Parvalbumin was found in almost all neurons of SOC nuclei in both species, while calbindin and calretinin were restricted to specific cell types and axonal terminal fields. In both species, calbindin displayed a ubiquitous and mostly selective distribution in neurons of the medial nucleus of trapezoid body (MNTB) including their terminal axonal fields in different SOC targets. In Meriones, calretinin and calbindin showed non-overlapping expression patterns in neuron somata and terminal fields throughout the SOC. In Monodelphis, co-expression of calbindin and calretinin was observed in the MNTB, and hence both CaBPs were also co-localized in terminal fields within the adjacent SOC nuclei. The distribution patterns of CaBPs in both species are discussed with respect to the intrinsic neuronal SOC circuits as part of the auditory brainstem system that underlie the binaural integrative processing of acoustic signals as the basis for localization and discrimination of auditory objects.
Mendoza-Elizalde, Sandra; Arteaga-Resendiz, Nancy K.; Valencia-Mayoral, Pedro; Luna, Raúl C.; Moreno-Espinosa, Sarbelio; Arenas-Huertero, Francisco; Zúñiga, Gerardo; Velázquez-Guadarrama, Norma
The bacterium Helicobacter pylori exhibits great genetic diversity, and the pathogenic roles of its virulence factors have been widely studied. However, the evolutionary dynamics of H. pylori strains during stomach colonization are not well-characterized. Here, we analyzed the microevolutionary dynamics of the toxigenic strain vacAs1m1, the non-toxigenic strain vacAs2m2, and a combination of both strains in an animal model over time. Meriones unguiculatus were inoculated with the following bacteria: group 1-toxigenic strain vacAs1m1/cagA+/cagE+/babA2+; ST181, group 2-non-toxigenic strain vacAs2m2/cagA+/cagE+/babA2+; ST2901, and group 3-both strains. The gerbils were euthanized at different time points (3, 6, 12, and 18 months). In group 1, genetic alterations were observed at 6 and 12 months. With the combination of both strains, group 3 also exhibited genetic alterations at 3 and 18 months; moreover, a chimera, vacA m1-m2, was detected. Additionally, four new sequence types (STs) were reported in the PubMLST database for H. pylori. Synonymous and non-synonymous mutations were analyzed and associated with alterations in amino acids. Microevolutionary analysis of the STs (PHYLOViZ) identified in each group revealed many mutational changes in the toxigenic (vacAs1m1) and non-toxigenic (vacAs2m2) strains. Phylogenetic assessments (eBURST) did not reveal clonal complexes. Our findings indicate that the toxigenic strain, vacAs1m1, and a combination of toxigenic and non-toxigenic strains acquired genetic material by recombination. The allelic combination, vacAs2m1, displayed the best adaptation in the animal model over time, and a chimera, m1-m2, was also identified, which confirmed previous reports. PMID:27877163
Buerbank, Stefanie; Schilling, Achim; Schulze, Holger
Noise induced hearing loss (NIHL) is a common disease in modern societies and may lead to maladaptations within the auditory system that finally result in subjective tinnitus. Available therapies may only alleviate the symptoms rather than restore normal hearing. In a previous study we demonstrated that the prophylactic application of Ginkgo biloba extract EGb 761® significantly reduces NIHL and tinnitus development in our Mongolian gerbil (Meriones unguiculatus) animal model. Here, we tested whether the application of EGb 761® has beneficial effects after the formation of permanent NIHL and tinnitus. To this end we monitored the therapeutic effects of EGb 761® on noise trauma-induced changes in signal processing within the auditory system of our animal model by behavioral (acoustic startle response, ASR) and electrophysiological approaches (auditory brainstem responses, ABR). We found that–in contrast to vehicle–three weeks of daily oral EGb 761® treatment (100 mg/kg body weight) led to a restoration of hearing thresholds back to pre-trauma conditions. In addition, all 9 animals that displayed behavioral signs of subjective tinnitus showed improvement, with 7 of them showing complete relief of tinnitus symptoms during the time of EGb 761® treatment. After discontinuation of EGb 761® treatment, tinnitus related behavior reappeared in all but one of these animals while auditory thresholds remained restored. A detailed analysis of ABR waves revealed that EGb 761® treatment did not simply change auditory processing back to pre-trauma conditions, but led to subtle changes of ABR wave amplitude and latency at different levels of the auditory pathway, with an overall increase of response to low stimulus intensities and a decrease at high intensities. The functional relevance of these changes may be the observed improvement of hearing thresholds while at the same time suppression of responses to high stimulus intensities may point to a global inhibitory
Mendoza-Elizalde, Sandra; Arteaga-Resendiz, Nancy K; Valencia-Mayoral, Pedro; Luna, Raúl C; Moreno-Espinosa, Sarbelio; Arenas-Huertero, Francisco; Zúñiga, Gerardo; Velázquez-Guadarrama, Norma
The bacterium Helicobacter pylori exhibits great genetic diversity, and the pathogenic roles of its virulence factors have been widely studied. However, the evolutionary dynamics of H. pylori strains during stomach colonization are not well-characterized. Here, we analyzed the microevolutionary dynamics of the toxigenic strain vacAs1m1, the non-toxigenic strain vacAs2m2, and a combination of both strains in an animal model over time. Meriones unguiculatus were inoculated with the following bacteria: group 1-toxigenic strain vacAs1m1/cagA+/cagE+/babA2+; ST181, group 2-non-toxigenic strain vacAs2m2/cagA+/cagE+/babA2+; ST2901, and group 3-both strains. The gerbils were euthanized at different time points (3, 6, 12, and 18 months). In group 1, genetic alterations were observed at 6 and 12 months. With the combination of both strains, group 3 also exhibited genetic alterations at 3 and 18 months; moreover, a chimera, vacA m1-m2, was detected. Additionally, four new sequence types (STs) were reported in the PubMLST database for H. pylori. Synonymous and non-synonymous mutations were analyzed and associated with alterations in amino acids. Microevolutionary analysis of the STs (PHYLOViZ) identified in each group revealed many mutational changes in the toxigenic (vacAs1m1) and non-toxigenic (vacAs2m2) strains. Phylogenetic assessments (eBURST) did not reveal clonal complexes. Our findings indicate that the toxigenic strain, vacAs1m1, and a combination of toxigenic and non-toxigenic strains acquired genetic material by recombination. The allelic combination, vacAs2m1, displayed the best adaptation in the animal model over time, and a chimera, m1-m2, was also identified, which confirmed previous reports.
Red carrots contain lycopene in addition to ß-Carotene. The utility of red carrot as a functional food depends in part on the bioavailability of its constituent carotenoids. Lycopene bioavailability was compared in Mongolian gerbils (Meriones unguiculatus) fed freeze-dried red carrot and tomato pa...
Dondzillo, Anna; Thompson, John A.; Klug, Achim
Principal neurons in the medial nucleus of the trapezoid body (MNTB) receive strong and temporally precise excitatory input from globular bushy cells in the cochlear nucleus through the calyx of Held. The extremely large synaptic currents produced by the calyx have sometimes led to the view of the MNTB as a simple relay synapse which converts incoming excitation to outgoing inhibition. However, electrophysiological and anatomical studies have shown the additional presence of inhibitory glycinergic currents that are large enough to suppress action potentials in MNTB neurons at least in some cases. The source(s) of glycinergic inhibition to MNTB are not fully understood. One major extrinsic source of glycinergic inhibitory input to MNTB is the ventral nucleus of the trapezoid body. However, it has been suggested that MNTB neurons receive additional inhibitory inputs via intrinsic connections (collaterals of glycinergic projections of MNTB neurons). While several authors have postulated their presence, these collaterals have never been examined in detail. Here we test the hypothesis that collaterals of MNTB principal cells provide glycinergic inhibition to the MNTB. We injected dye into single principal neurons in the MNTB, traced their projections, and immunohistochemically identified their synapses. We found that collaterals terminate within the MNTB and provide an additional source of inhibition to other principal cells, creating an inhibitory microcircuit within the MNTB. Only about a quarter to a third of MNTB neurons receive such collateral inputs. This microcircuit could produce side band inhibition and enhance frequency tuning of MNTB neurons, consistent with physiological observations. PMID:27489949
Hübner, Marc P; Torrero, Marina N; McCall, John W; Mitre, Edward
Litomosoides sigmodontis is a filarial nematode that is used as a mouse model for human filarial infections. The life cycle of L. sigmodontis comprises rodents as definitive hosts and tropical rat mites as alternate hosts. Here, we describe a method of infecting mice with third stage larvae (L3) extracted from the pleural space of recently infected jirds (Meriones unguiculatus). This method enables infection of mice with a known number of L3 larvae without the time-consuming dissection of L3 larvae from mites and results in higher worm recovery and patency rates than conventional methods. Additionally, this method allows for geographical separation of the facility maintaining the L. sigmodontis life cycle from the institution at which mice are infected.
Shigeno, Shizugi; Fujimaki, Yasunori; Toriyama, Kanan; Ichinose, Akitoyo; Mitsui, Yoshinori; Aoki, Yoshiki; Kimura, Eisaku
A single-dose treatment with diethylcarbamazine (DEC) reduced microfilaria (mf) counts of Brugia pahangi by >90% at 30 min post-treatment in Mongolian jirds (Meriones unguiculatus). The reduction was followed by a rapid increase in microfilaremia, with the count reaching pretreatment level in 3 hr. The mechanisms behind this temporary reduction of mf were investigated. Without treatment, mf accumulated in the lungs. At 30 min post-treatment, they had moved from the lungs and accumulated in the muscle. At the same time, electron microscopy revealed many mf in the muscle interstitium. DEC concentrations at 30 min were much lower in the muscle (12.2 microg/g of tissue) than in the lungs, liver, and kidneys (19.8-40.7 microg/g), all of which declined to < 0.6 microg/g by 3 hr. The presence of mf in the muscle would be advantageous for avoiding high DEC concentrations, and their extravascular location could prevent attack by host effector cells.
Sharma, M P; Mathur, R S; Mehta, K
Borax was injected at a dose level of 250 mg/kg b. wt for 16 days (total dose 4 g/kg b. wt) s.c. to active adult male gerbils. Borax caused several degenerative changes in the testes, of which giant cell formation, pyknosis and exfoliation are prominent. The increased activity of phosphatases was also noticed.
Dixit, V P; Sharma, O P; Agrawal, M
1. Light deprivation either by enucleation or darkness resulted in a wide-spread testicular damage. The changes consisted of loss of type A spermatogonia, spermatocytes, spermatids and spermatozoa. 2. The atrophic testes of eyeless gerbils regenerated after 20 weeks and were indistinguishable from those of untreated, continuous light exposed animals. The reversible effects were not seen in continuous dark exposure. 3. Light deprivation (enucleation/continuous darkness) inhibits the synthesis of RNA, protein and sialic acid in the testes, epididymides and seminal vesicles. The testicular cholesterol and alkaline phosphatase activity was increased. 4. Haemoglobulin, haematrocrit and serum-transaminase levels were all the time within normal limits. Histological preparations of the liver showed normal architecture. 5. Reduced androgen production following a long term light deprivation was reflected in low levels of RNA and sialic acid in the testes and epididymides and shrunken Leydig cell nuclei. 6. In conclusion, light deprivation caused damage to the male genital tract of gerbils.
Ukaji, Takao; Kai, Osamu
We designed primer sets specific to the immunoglobulin (Ig) heavy-chain constant region (IGHC) genes in Mongolian gerbil (Meriones unguiculatus) to amplify five gerbil IGHC cDNA sequences, Cμ, Cγ1, Cγ2, Cε, and Cα. Five gerbil-mouse heterohybridomas B11D2(C2), B11E2(D5).M, B5-3, D5, and C11 respectively expressed Cγ1, Cμ, Cγ2, Cγ2, and Cγ1. In contrast, a commercial isotyping kit for mouse Igs identified Cγ1, Cμ, Cγ3, Cγ3, and Cγ1, respectively, misidentifying gerbil IgG2 as IgG3 by cross-reactivity with anti-mouse IgG3 polyclonal antibody. These primer sets will allow the accurate estimation of gerbil Ig classes and IgG subclasses. These results from three gerbil strains indicate that the primer sets can be used for isotype analysis of gerbil mAbs and for evaluation of humoral immunity.
Petri, W A; Ravdin, J I
No protective antigens from Entamoeba histolytica have been previously defined. We tested the ability of the galactose-specific adherence lectin of E. histolytica to elicit a protective immune response in conjunction with Freund's incomplete and complete adjuvants. The gerbil (Meriones unguiculatus) model of an experimental amebic liver abscess was used. Gerbils were immunized intraperitoneally or subcutaneously with 10 micrograms of the affinity-purified lectin in complete Freund's adjuvant and then at 2 and 4 weeks with 10 micrograms of the lectin in incomplete Freund's adjuvant. All of the immunized animals developed antilectin antibody titers of greater than 1/1,024 as measured by a radioimmunoassay. The gerbil antilectin antibodies were shown by Western immunoblotting to be directed to the heavy subunit but not the light subunit of the lectin. Immune gerbil sera inhibited amebic adherence by 100% at a 1/10 dilution. Immune and control gerbils were challenged at 6 weeks by the intrahepatic injection of 5 x 10(5) E. histolytica trophozoites. Four independent trials demonstrated complete protection from amebic liver abscess formation in 67% of lectin-immunized gerbils. Unexpectedly, liver abscess weights were significantly higher in the gerbils that failed to become immune than in the control animals. Our results demonstrate that the galactose lectin is a protective antigen and provide an immune-animal model to study the mechanisms of protection and potential disease exacerbation conferred by the antilectin immune response. Images PMID:1987067
Sun, Yi-Sheng; Li, Ya-jing; Xia, Yong; Xu, Fang; Wang, Wei-wei; Yang, Zhang-Nv; Lu, Hang-Jing; Chen, Zhi-Ping; Miao, Zi-Ping; Liang, Wei-Feng; Xu, Zhi-Yao; Dong, Hong-Jun; Qiu, Dan-Hong; Zhu, Zhi-Yong; van der Veen, Stijn; Qian, Jie; Zhou, Bin; Yao, Ping-Ping; Zhu, Han-Ping
Coxsackievirus A16 (CA16) is one of the major pathogens associated with human hand, foot, and mouth disease (HFMD) in the Asia-pacific region. Although CA16 infections are generally mild, severe neurological manifestations or even death has been reported. Studies on CA16 pathogenesis and vaccine development are severely hampered because the small animal models that are currently available show major limitations. In this study, gerbils (Meriones unguiculatus) were investigated for their suitability as an animal model to study CA16 pathogenesis and vaccine development. Our results showed that gerbils up to the age of 21 days were fully susceptible to CA16 and all died within five days post-infection. CA16 showed a tropism towards the skeletal muscle, spinal cord and brainstem of gerbils, and severe lesions, including necrosis, were observed. In addition, an inactivated CA16 whole-virus vaccine administrated to gerbils was able to provide full protection to the gerbils against lethal doses of CA16 strains. These results demonstrate that gerbils are a suitable animal model to study CA16 infection and vaccine development. PMID:27667023
de Oliveira, Francisco Carlos R; Stabenow, Cristiane da S; Massad, Fabiana V; Lopes, Carlos Wilson G
Nine Mongolian gerbils (Meriones unguiculatus) were fed with 5.6 x 10(5) Cystoisospora sporulated oocysts orally. After 28 days post inoculation (DPI) four animals were euthanized, and their mesenteric lymph nodes were removed and they were submitted to peptic digestion technique and samples of them were submitted to transmission electron microscopy for hypnozoites identification. From lymph nodes digestion 4 x 10(2) hypnozoites/mL were obtained. Morphologically they were banana or stick form in shape, and measured 18.17 (15.09-20.02) in length by 6.21 (5.48-7.06) microm in width. In the same experiment, at 6 DAI, five gerbils were posted and liver, mesenteric lymph nodes and spleen were removed from each animal and were homogenized before given to three cats free of coccidia. All visceras used individually in each cat were capable to induce infection of species, C. felis and C. rivolta.
Fu, Heping; Zhang, Jinwei; Shi, Dazhao; Wu, Xiaodong
Rodent pest population outbreaks occur frequently in grassland ecosystems in northern China. The Mongolian gerbil (Meriones unguiculatus) is a dominant pest rodent which is distributed across the semi-desert grasslands of Inner Mongolia, China. In 2009, we studied the contraceptive effect of levonorgestrel-quinestrol (EP-1), concentration 50 ppm, on a wild Mongolian gerbil population. The one-off contraceptive treatment was compared with a control group using a semi-monthly live trapping method in the Ordos Semi-desert Grassland Region of Inner Mongolia. The results show that juveniles were not recruited in spring in the treatment group. Ratios of juveniles in the control and treatment groups showed significant semi-monthly differences from spring to summer (one-way ANOVA, F2, 14 = 7.53, P < 0.05). Between both groups, annual fluctuations of juvenile and total population densities were significantly different respectively (F2, 14 = 4.64, P < 0.05; F2, 18 = 7.72, P < 0.05). The contraceptive EP-1 delayed the normal reproductive pattern of Mongolian gerbil populations. This suppressed birth rates of gerbil populations, reduced their densities, and changed their age structures. The period of EP-1 baiting should be extended but it could be an ideal method for controlling Mongolian gerbil populations during each breeding season.
Risoud, Michaël; Bonne, Nicolas-Xavier; Fourdrinier, Martin; Hubert, Thomas; Vincent, Christophe
The Mongolian gerbil (Meriones unguiculatus) is commonly used in hearing research because the hearing frequency spectrum of the gerbil is rather similar to that of the human being. However, a precise description of the surgical post-auricular route has not been reported. The aim of this technical note is to provide details on the procedure and the surgical anatomy of the post-auricular route in the Mongolian gerbil. Surgery was performed under general anesthesia on eight (2 males and 6 females) adult Mongolian gerbils. All steps of the post-auricular route were detailed. This surgery provided an access to the following structures: the semi-circular posterior and lateral canals, the external auditory meatus, the tympanic membrane, the round window, the stapes, the stapedial artery and the reliefs of the cochlea. No anatomic variation was noticed among the 8 animals. This post-auricular route in the Mongolian gerbil defines a brief and simple surgery, overall standardized as a consequence of the absence of common anatomic variation, with painless and uncomplicated post-operative stage.
Wei, Yongfang; Hong, Qing; Chen, Daixiong; Liang, Chenjie; Liu, Haiying; Luo, Xiaodong; Zhu, Xunmin
The Mongolian gerbil (Meriones unguiculatus) has been indicated to be a useful experimental model host for studying nematode. To understand the possibility of the Mongolian gerbil as an animal model of Angiostrongylus cantonensis infection, we investigated the development, migration, and tissue distribution of A. cantonensis and pathological changes in the brain and lungs of the infected Mongolian gerbils. The first stage larvae of A. cantonensis in the stool of the infected gerbils were examined by direct smear method at 45th day postinfection (PI). In addition, a group of the infected gerbils were orally fed with albendazole (100 mg/kg/day/gerbil) at the 8th day PI and continued for 3 consecutive days. The results showed that mortality rate of Mongolian gerbils infected with 10 third stage larvae of A. cantonensis was about 62% at the 30th day PI; the peak period of death was from the 23rd to 30th day PI. About 93% (27/29) of the worms in survivors of infected gerbils could develop to complete sexual maturity at the 46th day PI, and the examinations of 12 gerbils in G3 group revealed that first stage larvae of A. cantonensis could be found in the feces of 4 gerbils at the 45th day PI. About 80% of the worms were in the brain of infected gerbils and 20% in the lungs from the 23rd to 25th day PI; during migration of the worms from the brain to lungs, more than 90% of the worms arrived to the lungs and less than 10% of them still stayed in the brain during from the 45th to 46th day PI. Pathological examination revealed that injuries induced by A. cantonensis in infected gerbils were characterized by eosinophilic meningitis and granulomatous pneumonia. Otherwise, albendazole exhibited a good larvicidal activity in the infected Mongolian gerbils. In contrast with infected control group, no gerbils died in administering albendazole, no worms were recovered, and no nervous system symptoms caused by the infection occurred at the 26th day PI. These findings clearly
Biofortification of staple crops to increase provitamin A carotenoids is a promising technique to alleviate vitamin A deficiency. ß-Carotene (ßC) and ß-cryptoxanthin (ßCX) are low in typical maize but higher in biofortified varieties. In vitro screening methods evaluate bioaccessibility of carotenoi...
McGinn, M D; Faddis, B T
Kangaroo rats develop spongiform degeneration of the central auditory system similar to that seen in the gerbil. Light microscopic and transmission electron microscopic study of the cochlear nucleus and auditory nerve root (ANR) of Dipodomys deserti and D. merriami show that spongiform lesions develop in dendrites and oligodendrocytes of the cochlear nucleus and in oligodendrocytes of the ANR that are morphologically indistinguishable from those extensively described in the Mongolian gerbil, Meriones unguiculatus. As in Mongolian gerbils, the spongiform degeneration in Dipodomys were much more numerous in animals continually exposed to modest levels of low-frequency noise (< 75 dB SPL). The kangaroo rats with extensive spongiform degeneration also show slightly, but significantly, elevated auditory brainstem evoked response (ABR) thresholds to low-frequency stimuli, a result also found in Mongolian gerbils. These results suggest that the elevated ABR thresholds may be the result of spongiform degeneration. Because low-frequency noise-induced spongiform degeneration has now been shown in the cochlear nucleus of animals from separate families of Rodentia (Heteromyidae and Muridae), the possibility should be investigated that similar noise-induced degenerative changes occur in the central auditory system of other mammals with good low-frequency hearing.
de Godoy, Isabela; de Campos, Camila Gonçalves; Pescador, Caroline Argenta; Galceran, João Vitor Amorim; Cândido, Stéfhano Luis; Dutra, Valéria; Nakazato, Luciano
Conidiobolomycosis is an emerging entomophthoramycosis caused by fungi Conidiobolus spp. Animal models are essential for the study of infectious disease in various areas such as pathogenesis, diagnostic methods, treatment and prevention. There is not currently an animal model for conidiobolomycosis. The aim of this study was to create an experimental infection protocol for Conidiobolus lamprauges in gerbils (Meriones unguiculatus). The study animals were randomly divided into four groups of four animals: immunosuppressed with cyclophosphamide (CPA) and infected with C. lamprauges (G1), immunocompetent and infected with C. lamprauges (G2), immunosuppressed with CPA (G3), and an immunocompetent control group (G4). Clinical signs were observed only in G1 animals, where the mortality rate reached 75% by day 7 after infection (AI) with a median survival of 2 days. C. lamprauges was detected only in G1, both by PCR and by isolation. Necropsies of the G1 animals showed lesions in the nasal cavity and lung tissue. These lesions were characterized by polymorphonuclear infiltrate cells and by the presence of hyphal structures under silver staining. This animal model will be useful for further investigation of diseases caused by C. lamprauges, particularly of those associated with immunosuppression factors in naturally occurring animal infections.
Schulze, Holger; Hess, Andreas; Ohl, Frank W; Scheich, Henning
The segregation of an individual sound from a mixture of concurrent sounds, the so-called cocktail-party phenomenon, is a fundamental and largely unexplained capability of the auditory system. Speaker recognition involves grouping of the various spectral (frequency) components of an individual's voice and segregating them from other competing voices. The important parameter for grouping may be the periodicity of sound waves because the spectral components of a given voice have one periodicity, viz. fundamental frequency, as their common denominator. To determine the relationship between the representations of spectral content and periodicity in the primary auditory cortex (AI), we used optical recording of intrinsic signals and electrophysiological mapping in Mongolian gerbils (Meriones unguiculatus). We found that periodicity maps as an almost circular gradient superimposed on the linear tonotopic gradient in the low frequency part of AI. This geometry of the periodicity map may imply competitive signal processing in support of the theory of "winner-takes-all".
Mauck, Matthew C.; Mancuso, Katherine; Kuchenbecker, James A.; Connor, Thomas B.; Hauswirth, William W.; Neitz, Jay; Neitz, Maureen
Delivery of foreign opsin genes to cone photoreceptors using recombinant adeno-associated virus (rAAV) is a potential tool for studying the basic mechanisms underlying cone based vision and for treating vision disorders. We used an in vivo retinal imaging system to monitor, over time, expression of virally-delivered genes targeted to cone photoreceptors in the Mongolian gerbil (Meriones unguiculatus). Gerbils have a well-developed photopic visual system, with 11-14% of their photoreceptors being cones. We used replication deficient serotype 5 rAAV to deliver a gene for green fluorescent protein (GFP). In an effort to direct expression of the gene specifically to either S or M cones, the transgene was under the control of either the human X-chromosome opsin gene regulatory elements, i.e., an enhancer termed the Locus Control Region (LCR) and L promoter, or the human S-opsin promoter. Longitudinal fluorescence images reveal that gene expression is first detectable about 14 days post-injection, reaches a peak after about 3 months, and is observed more than a year post-injection if the initial viral concentration is sufficiently high. The regulatory elements are able to direct expression to a subpopulation of cones while excluding expression in rods and non-photoreceptor retinal cells. When the same viral constructs are used to deliver a human long-wavelength opsin gene to gerbil cones, stimulation of the introduced human photopigment with long-wavelength light produces robust cone responses. PMID:18598398
Yang, Hui-Di; Wang, Qian; Wang, Zuoxin; Wang, De-Hua
Mongolian gerbils (Meriones unguiculatus) display food hoarding and thus provide an opportunity to study the neuromechanisms underlying this behavior. In the present study, male gerbils exhibited a bimodal expression of food hoarding behavior-some displayed high levels of food hoarding whereas others virtually lacked this behavior under normal laboratory conditions with free access to food. Food hoarding was found to be associated with an increase in neuronal activation, indicated by Fos immunoreactive (ir) staining, in several brain areas including the nucleus accumbens, ventral tegmental area (VTA), and lateral hypothalamus. Food hoarding was also associated with increases in the number of cells labeled for tyrosine hydroxylase (TH-ir), the rate limiting enzyme for dopamine conversion, and the number of cells co-labeled for TH-ir/Fos-ir in the VTA, suggesting that dopamine in the brain reward circuitry may be involved in food hoarding. Further, we found that 22 h of food deprivation induced food hoarding in some, but not all, males that naturally did not display food hoarding. In these males, however, food hoarding did not increase TH-ir or TH-ir/Fos-ir expression in the VTA. Together, these data indicate that male Mongolian gerbils display diverse phenotypes of food hoarding behavior and that dopamine in the brain reward circuitry may be involved in the control of naturally occurring, but not food deprivation-induced, food hoarding.
Shen, Wei; Zhang, Xue-Ying; Liu, Ding-Zhen; Wang, De-Hua
Parker's sperm competition model predicts a negative relationship between pre-copulatory (social status) and post-copulatory (sperm quality and quantity) sexually selected traits, however, empirical studies have revealed considerable inconsistency in this relationship. We hypothesized that there was a trade-off between pre- and post-copulatory sexually selected traits, and hormones (corticosterone, CORT; testosterone, T) orchestrate this relationship. In this study, we measured energetic parameters in the dominant-subordinate Mongolian gerbils (Meriones unguiculatus), whose relationship was established under chronic social encounters in a neutral arena, and then tested the relationship between their social status and sperm quality and quantity. Our results showed that dominant males initiated attack sooner and displayed more aggression, self-grooming and locomotion behaviors in daily social encounters across seven consecutive days. Dominant gerbils also had more and better quality of sperm than that of subordinate males, yet showed no significant differences in energy intake and RMR in comparison with subordinate individuals. In addition, dominant males had higher concentrations of serum T than subordinate males, whereas the concentrations of CORT showed a reverse pattern. The frequency and duration of aggression (indicative of social status) increased with elevated T concentrations. Sperm quality in terms of number and activity were associated with higher concentrations of serum T in dominant gerbils, whereas small sperm counts and poor-quality sperm were associated with relatively higher concentrations of serum CORT in subordinate gerbils. Together, our data indicated that there was no trade-off between pre- and post-copulatory sexually selected traits but hormones orchestrated the relationship between these traits in male Mongolian gerbils.
Atyakshin, D A; Bykov, E G
Optical (light) microscopy and histochemical techniques were used for the first-ever studies of the population characteristics of tissue basocytes in the jejunum mucous membrane in three groups of gerbils Meriones unguiculatus: flown over 12 days aboard space platform Foton-M3, subjected to spaceflight factors simulation (SFS) in dedicated system Kontur-L (2) and maintained in standard vivarium conditions (control). Space flight was shown to induce quantitative and qualitative changes in the population of jejunum mucus labrocytes. Reduction of the basocytes population, alterations in age composition and ratio of the morphofunctional cell types in microgravity were indicative of cytoplasmic aggregation intensity, paths of biosynthesis products release into the intersticium, and their tinctorial properties. Also, heparin maturation and liberalization into the extracellular space in support of the jejunum mucus adaptive functions progressed with greater intensity. SFS did not affect size of the basocytes population significantly although it did cause qualitative rearrangements in the population structure.
Abbas, Leila; Rivolta, Marcelo N.
The Mongolian gerbil, Meriones unguiculatus, has been widely employed as a model for studies of the inner ear. In spite of its established use for auditory research, no robust protocols to induce ototoxic hair cell damage have been developed for this species. In this paper, we demonstrate the development of an aminoglycoside-induced model of hair cell loss, using kanamycin potentiated by the loop diuretic furosemide. Interestingly, we show that the gerbil is relatively insensitive to gentamicin compared to kanamycin, and that bumetanide is ineffective in potentiating the ototoxicity of the drug. We also examine the pathology of the spiral ganglion after chronic, long-term hair cell damage. Remarkably, there is little or no neuronal loss following the ototoxic insult, even at 8 months post-damage. This is similar to the situation often seen in the human, where functioning neurons can persist even decades after hair cell loss, contrasting with the rapid, secondary degeneration found in rats, mice and other small mammals. We propose that the combination of these factors makes the gerbil a good model for ototoxic damage by induced hair cell loss. PMID:25783988
Atiakshin, D A; Bykov, E G; Il'in, E A; Pashkov, A N
Glycogen cytochemistry and distribution in hepatocytes of the classic liver lobules were studied in three groups of gerbils Meriones unguiculatus: vivarium, synchronous control and flown in the 12-d Foton-M3 mission. The control animals were shown to have the central glycogen distribution with a large pool of polysaccharides found in hepatocytes of the pericentral and intermediate lobules and a small pool in the periportal area. Glycogen in hepatocyte plasm was within the physiological norm in the alpha- and beta-granules, typically localized on the cell periphery. Exposure to the spaceflight conditions decreased significantly glycogen concentrations in each functional region of the hepatic lobules and reduced the gradient of polysaccharide distribution from the portal triads toward the central vein. In parallel, high glycogen heterogeneity formed in adjacent hepatocytes and loci. The presence of glycosomes evidenced disturbance of carbohydrates metabolism. In addition, intracellular topography of glycogen granules in cytoplasm was altered. Trends of glycogen in gerbils of the synchronous control were similar to the space flown animals but much less pronounced.
Hadi Mansouri, S; Siegford, Janice M; Ulibarri, Catherine
This study examined the response of the spinal nucleus of the bulbocavernosus (SNB) and the bulbocavernosus (BC) muscle, to testosterone in male Mongolian gerbils (Meriones unguiculatus) during the early postnatal period. Male gerbil pups were given testosterone propionate (TP) or vehicle for 2 days, then perfused on postnatal day (PND) 3, 5, 10 or 15. The BC and levator ani (LA) muscles were removed, weighed, and sectioned. Cross-sections of BC muscle fibers were measured and muscle fiber morphology examined. Spinal cords were removed and coronally sectioned in order to count and measure the SNB motoneurons. Following TP treatment, male pups of all ages had significantly heavier BC-LA muscles and larger fibers in the BC muscle compared to age-matched controls. The increase in muscle weight following TP treatment was greatest at PND10, while fiber size increased to a similar degree at all ages suggesting that hyperplasia as well as hypertrophy was responsible for the increase in muscle mass at this time. SNB motoneurons increased significantly in number and size with age and TP treatment. We hypothesize that the increase in SNB motoneuron number during normal ontogeny that can be augmented by TP treatment and represents an unusual means of establishing sexual dimorphism in the nervous system of a mammal through cell recruitment to the motor pool of a postnatal animal.
Grando, Thirssa H; Baldissera, Matheus D; Gressler, Lucas T; de Sá, Mariângela Facco; Bortoluzzi, Bruna N; Schafer, Andressa S; Ebling, Rafael C; Raffin, Renata P; Santos, Roberto C V; Stefani, Lenita M; Vaucher, Rodrigo; Leal, Marta L R; Monteiro, Silvia G
Gastrointestinal parasites are one of the biggest health problems faced in sheep, mainly due to their pathogenicity and resistance to drugs used to control these parasites. Thus, the following study aimed to assess the anthelmintic efficacy of Melaleuca alternifolia against Haemonchus contortus in gerbils (Meriones unguiculatus) experimentally infected. Three treatments were tested: M. alternifolia essential oil, popularly known as tea tree oil (TTO), a solid lipid nanocarrier made with essential oil of Melaleuca (nanoTTO), and terpinen-4-ol (terp-4-ol). In vivo studies were performed by determining the mean worm burden of H. contortus in gerbils TTO (0.75 mL/kg); nanoTTO (0.5 mL/kg) and terp-4-ol (0.5 mL l/kg) were able to reduce 46.36%; 48.64%, and 43.18% worm burden, respectively. H. contortus increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, as demonstrated by liver injury. It was found that the TTO, nanoTTO, and terp-4-ol were not toxic to liver and kidneys since hepatic and renal functions were not affected. Moreover, terp-4-ol was able to prevent increased levels of seric AST and ALT in infected animals, indicating a hepatoprotective effect. Thus, our results indicate that TTO, nanoTTO, and terp-4-ol are safe and efficient against H. contortus infection in gerbils, and possibly the terp-4-ol may be considered the compound present in the Melaleuca alternifolia responsible for parasitic action against H. contortus.
Nitsch, C; Scotti, A L; Nitsch, F M
In the gerbil (Meriones unguiculatus) hippocampal formation, the calcium-binding protein parvalbumin (PV) shows a unique species-specific distribution: it is present in the perforant path from the entorhinal cortex to the stratum molecular of the dentate are and cornu ammonis. A possible relation of this to the seizure-sensitivity of gerbils has been suggested. In addition, as in other species, PV is contained in a subpopulation of GABAergic nerve cells of the gerbil hippocampus. The characteristics of these PV-containing neurons are here described. Distribution and shape of the PV-positive neurons in general agreed with the features described for rat hippocampus with two notable exceptions: in CA2 PV-containing perikarya were densely crowded and gave rise to an intense immunoreactive plexus around the pyramidal cells and, in CA1, the number of stained neurons was variable, often much lower than in rats and occasionally not a single PV-positive neuron was present. In parasagittal brain sections of the lateralities 1.0, 1.6 and 2.2 mm from the midline, obtained from 27 male gerbils, the number of PV-containing neurons was determined. The data set obtained in CA3 and dentate area resembled unimodal distributions, while in CA1 a bimodal frequency distribution was present. Since parametric and non-parametric correlation tests rely on a unimodal distribution of the data set, they gave falsely significant values in CA1. The bimodal distribution suggests that, with respect to the PV-containing interneurons in CA1, two different populations of gerbils were included in our sample, those with many positive neurons and those with only a few. Since the nerve terminal staining is preserved also in those gerbils with only a few positive perikarya in CA1, it seems possible that an unknown factor influenced PV expression and storage in the soma. Sex, age, seasonal or circadian rhythm or quality of immunocytochemical staining did not influence the outcome of the quantitative
Mercer, N.J.; Holub, B.J.
The hepatic synthesis of sterol was measured in the male Mongolian gerbil (Meriones unguiculatus) in vivo following the administration of (/sup 3/H)water by monitoring the incorporation of radioactivity into digitonin-precipitable sterol. A diurnal rhythm in cholesterol synthesis was exhibited under conditions of ad libitum feeding with alternating 12-hour periods of light (0200 to 1400 hr) and dark (1400 to 0200 hr). The zenith was reached between 1500 and 2100 hr and the nadir approximately 10-12 hours later between 0200 and 0400 hr, which provided a zenith/nadir ratio of 9.6 to 1.0. The in vivo rates of hepatic sterol synthesis and plasma cholesterol levels were measured in gerbils fed semi-purified diets containing either 19.5% beef tallow + 0.5% safflower, 20% lard, or 20% safflower oil and widely differing ratios of polyunsaturated: saturated fatty acids. All diets were equalized to contain 0.01% cholesterol and 0.05% plant sterol. After 3 days on the experimental diets, the mean rates of cholesterol synthesis (nmol/g liver per hr) were 41.5, 26.6, and 13.8 for animals fed the diets containing beef tallow, lard, and safflower oil, respectively. After 7 and 14 days, synthetic rates were lowest in the gerbils fed safflower oil as were also the plasma cholesterol levels. These results indicate that the type of dietary lipid can significantly influence the in vivo rate of sterol biosynthesis in gerbil liver. This response may contribute, at least in part, to the observed differences in plasma cholesterol levels.
Colleta, Simone J; Antoniassi, Julia Q; Zanatelli, Marianna; Santos, Fernanda C A; Góes, Rejane M; Vilamaior, Patricia S L; Taboga, Sebastião R
Bisphenol A (BPA) and cadmium (Cd) are environmental pollutants that are implicated in potential reproductive effects, including damage to the prostate gland. Their action during puberty requires analysis to determine the relationship of these compounds with the testosterone peak that occurs during this phase. This study evaluated whether exposure to BPA and Cd during puberty can cause changes in the morphology, proliferation and cell death and androgen receptor (AR) immunostaining of the ventral prostates of normal and castrated male gerbils (Meriones unguiculatus), considering an acute exposure to the chemicals and evaluation after short (52d) and long (120d) periods. Generally, morphometric-stereological results demonstrated that administration of BPA and Cd (individually or in combination) increased epithelial height, smooth muscle layer (SML) thickness and nuclear area and perimeter, and that these parameters were reduced in castrated animals. In addition, these groups showed important inflammatory processes but not prostate lesions. The proliferation/death rates of prostatic cells obtained by PCNA and TUNEL immunostaining demonstrated increased cell death in the 52d groups; in contrast, the gland acquired a more proliferative nature in the 120d groups. AR immunostaining showed that BPA and Cd compounds interact with ARs in different ways depending on the evaluated period and the hormonal profile of the animal. We conclude that BPA and cadmium are important agents in changing the morphology, proliferation and death of prostatic cells, in addition to interacting with ARs in different patterns. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 48-61, 2017.
Mills, Jordan P; Simon, Philipp W; Tanumihardjo, Sherry A
Red carrots contain lycopene in addition to alpha- and beta-carotene. The utility of red carrot as a functional food depends in part on the bioavailability of its constituent carotenoids. Lycopene bioavailability was compared in Mongolian gerbils (Meriones unguiculatus) fed freeze-dried red carrot and tomato paste (Study 1, n = 47) and whole food extracts dissolved in cottonseed oil (Study 2, n = 39). Diets and supplements were equalized for lycopene and intakes did not differ. Both studies utilized negative (oil) and positive [purified lycopene (Lyc)] controls. In Study 1, vitamin A liver stores (0.68 +/- 0.13 micromol/liver) of the red carrot group did not differ from baseline (0.63 +/- 0.13 micromol/liver) and were greater than those of the tomato paste (0.43 +/- 0.12 micromol/liver), Lyc (0.51 +/- 0.14 micromol/liver), and control (0.38 +/- 0.17 micromol/liver) groups (P < 0.003). A similar pattern was observed in Study 2. In both studies, hepatic lycopene was higher in the tomato paste (82.7 +/- 26.7 and 80.7 +/- 20.2 nmol/liver) groups compared with red carrot groups (59.3 +/- 21.9 and 39.5 +/- 14.1 nmol/liver, P < 0.0001). Hepatic lycopene from tomato paste was higher than Lyc in Study 1, but tomato paste extract and Lyc did not differ in Study 2, when both were dissolved in oil. Red carrot maintains vitamin A status, but constituent beta-carotene may interfere with lycopene bioavailability. These results confirm prior studies in humans on the relative bioavailability of lycopene from red carrots and tomato paste and expand them by suggesting the mechanism and determining vitamin A value.
Kuznetsova, Tatyana A; Kam, Michael; Khokhlova, Irina S; Kostina, Natalia V; Dobrovolskaya, Tatiana G; Umarov, Marat M; Degen, A Allan; Shenbrot, Georgy I; Krasnov, Boris R
Rodents affect soil microbial communities by burrow architecture, diet composition, and foraging behavior. We examined the effect of desert rodents on nitrogen-fixing bacteria (NFB) communities by identifying bacteria colony-forming units (CFU) and measuring nitrogen fixation rates (ARA), denitrification (DA), and CO2 emission in soil from burrows of three gerbil species differing in diets. Psammomys obesus is folivorous, Meriones crassus is omnivorous, consuming green vegetation and seeds, and Dipodillus dasyurus is predominantly granivorous. We also identified NFB in the digestive tract of each rodent species and in Atriplex halimus and Anabasis articulata, dominant plants at the study site. ARA rates of soil from burrows of the rodent species were similar, and substantially lower than control soil, but rates of DA and CO2 emission differed significantly among burrows. Highest rates of DA and CO2 emission were measured in D. dasyurus burrows and lowest in P. obesus. CFU differed among bacteria isolates, which reflected dietary selection. Strains of cellulolytic representatives of the family Myxococcaceae and the genus Cytophaga dominated burrows of P. obesus, while enteric Bacteroides dominated burrows of D. dasyurus. Burrows of M. crassus contained both cellulolytic and enteric bacteria. Using discriminant function analysis, differences were revealed among burrow soils of all rodent species and control soil, and the two axes accounted for 91 % of the variance in bacterial occurrences. Differences in digestive tract bacterial occurrences were found among these rodent species. Bacterial colonies in P. obesus and M. crassus burrows were related to bacteria of A. articulata, the main plant consumed by both species. In contrast, bacteria colonies in the burrow soil of D. dasyurus were related to bacteria in its digestive tract. We concluded that gerbils play an important role as ecosystem engineers within their burrow environment and affect the microbial complex of
Murphy, James E.
Describes the natural habitat, life-history, and behavior of gerbils. These animals do not drink water, are virtually odorless, can withstand wide temperature ranges, and require minimal attention. As a result they have become popular in research and science classrooms in recent years. (JR)
Atiashkin, D A; Bykov, É G
Gastric wall of Meriones unguiculatus is distinguished by species-specific properties arising from the peculiar proportion of interstitium, muscle and epithelial tissues. Exposure to the factors of the 12-d Foton-M3 flight led to microfocal lesions of the mucous coat, dystrophic developments in the acid glands, dissociation of the mucous barrier function and deterioration of its biosynthetic function. Modifications of the tinctorial properties of the interstitium reticulum in every stomach layer progressed concurrently with reductions in prismatic epithelium height, as well as in mucous and muscular layer thickness. It is assumed that existence in the low gravity aboard the Biosat stimulated involutory processes in the gastric wall. Animals of the ground synchronous control conducted in the flight equipment mockup (Kontur-L) exhibited though similar yet less pronounced changes.
Johnson, Olga; Marais, Sumine; Walters, Jacklynn; van der Merwe, Elizabeth L; Alagaili, Abdulaziz N; Mohammed, Osama B; Bennett, Nigel C; Kotzé, Sanet H
The proportion of mucin phenotypes (which form the protective biofilm of the gastrointestinal tract) differs between intestinal regions. This study examines the distribution of mucin secreting cells in the gastrointestinal tracts of the Eastern spiny mouse (Acomys dimidiatus), King jird (Meriones rex) and Libyan jird (Meriones libycus), which inhabit the dry and hot deserts of Saudi Arabia. Intestinal tract samples were processed to wax and tissue sections stained with Alcian Blue-Periodic Acid Schiff (AB-PAS) and High Iron Diamine-Alcian Blue (HID-AB) in order to determine different mucin phenotypes by quantitative analysis. Mixed mucin secreting cells (combined neutral and acid) was the predominant mucin secreting cell type observed throughout the gastrointestinal tract in all species. Acid mucin secreting goblet cells were mainly located in the colon. A. dimidiatus presented with significantly more total sialo than sulfomucin secreting cells while the opposite was true for both Meriones species. The distribution of mucin secreting cells is therefore similar to previously reported results for small mammals not living under arid conditions.
A method is described for studying the morphological features of extensive axonal projections within the central nervous system of the gerbil, Meriones anguiculatus. Potentially long descending axonal projections between the auditory thalamus and lower brainstem were used as a model. The inferior colliculus (IC) in the tectum was injected in vivo with a fluorescent retrograde tracer, Fluoro-Gold, to label cells in the medial geniculate body (MGB) that had descending projections to the IC, and cells in the superior olivary complex (SOC) that had ascending projections to the IC. Another fluorescent retrograde tracer, fast blue, was injected into the cochlea to label olivocochlear (OC) cells in the SOC. Inferomedially curved parasagittal slices containing ipsilateral auditory cell groups from the thalamus to the brainstem were cut and descending axons of the pre-labeled MGB cells were traced anterogradely with Biocytin. After visualizing histologically the injected Biocytin, discretely labeled IC-projecting axons of the MGB cells were traced including their collaterals that extended further into the SOC. In the SOC, these axons terminated on pre-labeled cells including OC cells. The combination of anterograde and retrograde tracing in the slice preparations described here demonstrated extensive descending axonal projections from the thalamus to their targets in the lower brainstem that had known ascending/descending projections within the auditory system.
Bleich, Eva-Maria; Martin, Myriam; Bleich, André; Klos, Andreas
Mongolian gerbils are used as biomedical research models for a variety of diseases and are in some cases suited better than other rodents for basic research and therapeutic studies. The aim of this study was to establish and characterize a dextran sulphate sodium (DSS)-induced model in gerbils for the human inflammatory bowel disease (IBD) and to utilize them for a therapeutic study in vivo. Four concentrations (0.5%, 1%, 2% and 4%) of DSS were administered via drinking water for 7 days; based on these results, a concentration of 3% DSS was given for 9 days in a second approach. Fluid uptake and general clinical condition were assessed daily using a clinical score. Caecum and colon were scored histologically. Fluid uptake was affected by addition of DSS to the drinking water. First clinical symptoms were observed at day 4 of DSS treatment with a considerable increase in clinical score parameters only in gerbils receiving 2% or 4% DSS. Histologically, ulceration and inflammation were observed predominantly in the caecum of gerbils treated with at least 1% DSS; reproducible inflammation in the colon required at least 2% DSS. Using 3% DSS for 9 days, considerably more inflammation was induced in the colon, comparable with lesions usually observed in the mouse model. Using an optimized protocol, DSS treatment induces reproducibly typhlocolitis in Mongolian gerbils, rendering them as a useful model for IBD. PMID:20113376
Lingner, Andrea; Kugler, Kathrin; Grothe, Benedikt; Wiegrebe, Lutz
Reverberation can dramatically reduce the depth of amplitude modulations which are critical for speech intelligibility. Psychophysical experiments indicate that humans' sensitivity to amplitude modulation in reverberation is better than predicted from the acoustic modulation depth at the receiver position. Electrophysiological studies on reverberation in rabbits highlight the contribution of neurons sensitive to interaural correlation. Here, we use a prepulse-inhibition paradigm to quantify the gerbils' amplitude modulation threshold in both anechoic and reverberant virtual environments. Data show that prepulse inhibition provides a reliable method for determining the gerbils' AM sensitivity. However, we find no evidence for perceptual restoration of amplitude modulation in reverberation. Instead, the deterioration of AM sensitivity in reverberant conditions can be quantitatively explained by the reduced modulation depth at the receiver position. We suggest that the lack of perceptual restoration is related to physical properties of the gerbil's ear input signals and inner-ear processing as opposed to shortcomings of their binaural neural processing.
Berger-Tal, Oded; Mukherjee, Shomen; Kotler, Burt P; Brown, Joel S
Predator-prey interactions are often behaviourally sophisticated games in which the predator and prey are players. Past studies teach us that hungrier prey take higher risks when foraging and that hungrier predators increase their foraging activity and are willing to take higher risks of injury. Yet no study has looked at the simultaneous responses of predator and prey to their own and each other's hunger levels in a controlled environment. We looked for evidence of a state-dependent game between predators and their prey by simultaneously manipulating the hunger state of barn owls, and Allenby's gerbils as prey. The owls significantly increased their activity when hungry. However, they did not appear to respond to changes in the hunger state of the gerbils. The gerbils reacted strongly to the owls' state, as well as to their own state when the risk was perceived as high. Our study shows that predator-prey interactions give rise to a complex state-dependent game.
Schaefers, Andrea T. U.; Grafen, Keren; Teuchert-Noodt, Gertraud; Winter, York
Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils. PMID:20508828
Schaefers, Andrea T U; Grafen, Keren; Teuchert-Noodt, Gertraud; Winter, York
Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils.
Yeruham, I; Hadani, A; Galker, F
Splenectomized gerbils (Acomys cahirinus) have been found to be susceptible to Babesia ovis applied via blood inoculation, whereas intact gerbils were not infected. Blood from splenectomized latently infected gerbils caused infection in a splenectomized lamb. Intact Acomys cahirinus gerbils did not become infected by B. ovis, and all captured rodents in an enzootic area, intact and splenectomized, were found to be negative for B. ovis. It can thus be concluded that Acomys cahirinus does not serve as a natural reservoir for B. ovis.
Arumugam, Sridhar; Pfarr, Kenneth M; Hoerauf, Achim
The rodent filaria Litomosoides sigmodontis harbour Wolbachia, endosymbionts essential for worm embryogenesis, larval development and adult survival. To study the effect of tetracycline, which depletes Wolbachia, on the development of microfilariae (L1s, MF) to L3 in the intermediate host Ornithonyssus bacoti, and to observe the development of Wolbachia-depleted L3s in Mongolian gerbils (Meriones unguiculatus); microfilaremic gerbils were treated orally with tetracycline for 6 weeks (primary infected Tet) or untreated (primary Con). Treatment resulted in a significant reduction of Wolbachia per MF in primary Tet gerbils. Naïve mites then fed on the primary Tet and primary Con gerbils in the week after treatment ended, when MF levels were not significantly different, and used to infect new gerbils (secondary infected ) Tet, secondary Con) via natural infection. The infection rate from dissected mites was 9% and 54% (primary Tet and primary Con, respectively). After 3 months, worms were isolated from secondary gerbils. Significantly fewer female worms developed in secondary Tet gerbils. In contrast, there was no difference in the number of male worms that developed in secondary gerbils, resulting in a male biased sex-ratio. Although secondary Tet male worms had fewer Wolbachia than secondary Con males, development was not impaired. Female worms that developed from Wolbachia-depleted MF had Wolbachia levels equivalent to worms from secondary Con animals. Thus, tetracycline pre-treatment selected for female worms with high numbers of Wolbachia, whereas male worms had median Wolbachia levels significantly lower than secondary Con males. Therefore, female worms require a higher threshold of Wolbachia for their development. The worms analysed were only exposed to tetracycline as MF, ruling out direct effects of tetracycline during larval development in the mites or secondary gerbils, suggesting that the depletion of Wolbachia in MF was the cause of impaired larval
Zhang, T; Cieslak, P R; Stanley, S L
Amebiasis, infection by the intestinal protozoan parasite Entamoeba histolytica, is a leading parasitic cause of death. As a step in the development of a recombinant antigen vaccine to prevent E. histolytica infection, we looked at the ability of a recombinant version of the serine-rich E. histolytica protein (SREHP) to elicit a protective immune response against invasive amebic disease. Gerbils, a standard model for amebic liver abscess, were immunized with either a recombinant SREHP/maltose-binding protein (MBP) fusion, recombinant MBP alone, or phosphate-buffered saline (PBS), all combined with complete Freund's adjuvant. In the first trial (group 1), gerbils received a primary and two booster immunizations intraperitoneally; in the second trial (group 2), gerbils were immunized by a single intradermal injection. SREHP/MBP-immunized gerbils in both groups produced antibody to native SHEHP and developed delayed-type hypersensitivity responses to recombinant SREHP. All gerbils were challenged by an intrahepatic injection with 5 x 10(4) virulent E. histolytica HM1-IMSS trophozoites. Complete protection from amebic liver abscess was seen in 64% of the SHEHP/MBP-immunized gerbils in group 1 and in 100% of the SREHP/MBP-immunized gerbils in group 2. There was no protection observed in MBP- or PBS-immunized gerbils in either group. Our results indicate that the SREHP molecule has potential as a vaccine to prevent amebic infection and demonstrate that successful vaccination of animals with recombinant E. histolytica antigen vaccines is possible. Images PMID:8132322
Pritchett-Corning, Kathleen R; Gaskill, Brianna N
In cases where different species might be housed in the same room or secondary enclosure, the Guide for the Care and Use of Laboratory Animals recommends that the animals should be behaviorally compatible and have the same health status. Syrian hamsters and Mongolian gerbils, both desert-dwelling rodents, appear to be reasonable candidates for such a combination. This study was undertaken to evaluate whether housing hamsters and gerbils in the same secondary enclosure is an acceptable practice. Weanling and breeding-age hamsters and gerbils were housed in open-topped cages in an isolator for 5 mo; the isolator also contained with nude and haired mice, which acted as sentinels. Cages housing hamsters and gerbils were rotated between species, and dirty bedding was exchanged between species in an effort to transmit microorganisms. In addition, sentinel mice housed in the isolator were supplied with dirty bedding from both hamsters and gerbils. Neither species showed clinical signs of illness, the health status of neither the hamsters nor the gerbils changed significantly, and the sentinel mice acquired only 2 infectious organisms, a Helicobacter species and Staphylococcus aureus. Both hamsters and gerbils bred successfully when housed together in the same isolator, and no infanticide or mortality was seen. Breeding performance did not differ between isolator breeding and barrier breeding. This study supports the housing of hamsters and gerbils in the same secondary enclosure.
Pritchett-Corning, Kathleen R; Gaskill, Brianna N
In cases where different species might be housed in the same room or secondary enclosure, the Guide for the Care and Use of Laboratory Animals recommends that the animals should be behaviorally compatible and have the same health status. Syrian hamsters and Mongolian gerbils, both desert-dwelling rodents, appear to be reasonable candidates for such a combination. This study was undertaken to evaluate whether housing hamsters and gerbils in the same secondary enclosure is an acceptable practice. Weanling and breeding-age hamsters and gerbils were housed in open-topped cages in an isolator for 5 mo; the isolator also contained with nude and haired mice, which acted as sentinels. Cages housing hamsters and gerbils were rotated between species, and dirty bedding was exchanged between species in an effort to transmit microorganisms. In addition, sentinel mice housed in the isolator were supplied with dirty bedding from both hamsters and gerbils. Neither species showed clinical signs of illness, the health status of neither the hamsters nor the gerbils changed significantly, and the sentinel mice acquired only 2 infectious organisms, a Helicobacter species and Staphylococcus aureus. Both hamsters and gerbils bred successfully when housed together in the same isolator, and no infanticide or mortality was seen. Breeding performance did not differ between isolator breeding and barrier breeding. This study supports the housing of hamsters and gerbils in the same secondary enclosure. PMID:26045450
McGinn, M D; Faddis, B T
Spongiform lesions arise in dendrites and glia in the brainstem of domestic Mongolian gerbils. Most pronounced within the cochlear nucleus (CN), this disorder is dynamic and progressive; the lesions increase in number, size, and extent with age. It has not been clear whether these spongioid lesions either cause or are associated with significant neural degeneration. In contrast, feral Mongolian gerbils (wild-trapped in Tuva) and their offspring show few spongiform lesions. The Tuvan gerbils provide an appropriate within-species control. We compared degeneration in the brainstem of domestic and Tuvan gerbils using the amino-cupric-silver (ACS) stain of de Olmos et al. [(1994) Neurotoxicol. Teratol., 16:545-561]. Positive histologic controls were provided by cerebellar stab wounds in domestic gerbils and by unilateral kainic acid injections into the CN of Tuvan gerbils. The ACS stain revealed extensive degeneration of axons, terminals, dendrites, and neurons in the brainstem of domestic gerbils. Neurodegeneration was most pronounced in the CN and was coextensive with spongiform lesions. Neurodegeneration was also seen in the trapezoid body, lateral lemniscus, and inferior colliculus, but was less pronounced than in the CN. The cerebellar stab wounds resulted in silver-stained Purkinje cells restricted to the stab wound local region. Kainic acid produced extensive neuronal and spongiform degeneration of the injected CN that was very similar to that spontaneously occurring in domestic gerbils. In contrast, the non-injected CN of Tuvan gerbils showed no neuronal or spongiform degeneration with the ACS stain. We conclude that, in domestic gerbils, the naturally occurring spongiform lesions of the CN and the accompanying neurodegeneration are both results of a common mechanism, most probably excitotoxic.
Demas, G E; Bartness, T J
Food hoarding plays an important role in the energetic repertoire of a variety of mammalian species. Both food hoarding and food intake have been examined in rodents using several energetic challenges including food deprivation, treatment with metabolic fuel blockers, and enhancement of fuel storage. In the present experiment, we examined food hoarding by female jirds (Meriones shawi), a desert rodent species occupying the arid steppes and desert regions of Egypt. Jirds are prodigious hoarders in the field; however, virtually nothing is known about their hoarding within controlled laboratory settings. In the present study, the effects of food deprivation as well as alterations in metabolic fuel utilization (i.e., 2-deoxy-D-glucose and isophane insulin) on food hoarding and food intake were tested in female jirds using a simulated burrow system. Jirds decreased body mass and increased food consumption following either 32 or 56-h food deprivation. Food hoarding, however, was virtually abolished after food deprivation and treatment with 2-DG. In contrast, isophane insulin treatment had no effect on food consumption or hoarding in this species. Taken together, the present results suggest that total body mass (fat), rather than short-term metabolic fuel utilization, regulates both food consumption and hoarding in female jirds. In addition, these results provide a novel set of appetitive responses to these energetic challenges in small mammals.
Boettcher, Flint A.
The effect of age on susceptibility to noise-induced hearing loss (NIHL), the effect of gender on the interaction of age-related hearing loss (ARHL) and NIHL, and the relative contributions of ARHL and NIHL to total hearing loss are poorly understood. The issues are difficult to resolve empirically in human subjects because of lack of control over extrinsic variables and for ethical reasons. Accordingly, these issues were examined in a well-studied animal model of both ARHL and NIHL, the Mongolian gerbil. Animals were exposed to an intense tone (3.5 kHz, 113 dB SPL, 1 h) either as young adults (6-8 months) or near the end of the average lifespan of the species (34-38 months). Hearing thresholds were determined with the auditory brainstem response (ABR). ARHL was approximately 5-10 dB, with slightly more observed in males at 16 kHz (p<0.05). NIHL of approximately 15-20 dB was similar for the young and old groups, suggesting no differences in susceptibility as a function of age. There were no gender differences in NIHL. The relative contributions of ARHL and NIHL to total hearing loss in aged, noise-exposed gerbils were predicted by an addition of ARHL and NIHL in dB, similar to an international standard on hearing loss allocation, ISO-1999 [Determination of Occupational Noise Exposure and Estimation of Noise-Induced Hearing Impairment (1990)]. Previous evaluations of ISO-1999 using the gerbil animal model concluded that addition of ARHL and NIHL in dB overpredicts total hearing loss. However, in these studies, ARHL was large and nearly equal to NIHL. In the current study, where ARHL was much less than NIHL, addition of the two factors in dB, as recommended by ISO-1999, results in fairly accurate predictions of total hearing loss.
Hayes, K C; Pronczuk, Andrzej; Wijendran, Vasuki; Beer, Michael
To determine whether phytosterols (PST) facilitate excretion of whole body cholesterol and whether dietary fat or enhancing gallbladder contraction with curcumin might influence this process, four experiments were conducted in gerbils. In Experiment 1, naive gerbils received cholesterol-free purified diets with 30% energy from fat and 0% or 0.75% free PST from tall oil for 4 weeks. In Experiment 2, body cholesterol pools were expanded by feeding a diet containing 0.3% cholesterol for 3 weeks. Subsequently, PST was provided in either fat-free or normal-fat diets without cholesterol for only 2 h each morning, followed by a low-fat diet for the rest of the day and food restriction overnight. In Experiment 3, gerbils were preloaded with cholesterol, followed by either PST alone or PST+curcumin to enhance gallbladder contraction. In Experiment 4, curcumin or curcumin+PST were fed with 30% as fat and 0.15% cholesterol throughout the study. Because of the small whole body cholesterol pool in Experiment 1, the impact of PST was limited. When whole body cholesterol was expanded in Experiments 2 and 3, subsequent reductions of liver esterified cholesterol by PST were significant. In the presence of dietary fat, PST caused a greater reduction (23%) than in a fat-free diet (8%) compared to respective controls. Curcumin (Experiments 3 and 4) proved ineffective in reducing liver or plasma cholesterol pools, and the 3:1 ratio between PST/diet cholesterol was less effective at blocking cholesterol absorption than a 5:1 ratio previously employed. Thus, free PST removed whole body cholesterol, which was enhanced by concomitant fat intake, but was unaffected by a gallbladder contracting agent.
Overstreet, Edward H.; Ruggero, Mario A.
Stapes vibrations were measured in deeply anesthetized adult and neonatal (ages: 14 to 20 days) Mongolian gerbils. In adult gerbils, the velocity magnitude of stapes responses to tones was approximately constant over the entire frequency range of measurements, 1 to 40 kHz. Response phases referred to pressure near the tympanic membrane varied approximately linearly as a function of increasing stimulus frequency, with a slope corresponding to a group delay of 30 μs. In neonatal gerbils, the sensitivity of stapes responses to tones was lower than in adults, especially at mid-frequencies (e.g., by about 15 dB at 10-20 kHz in gerbils aged 14 days). The input impedance of the adult gerbil cochlea, calculated from stapes vibrations and published measurements of pressure in scala vestibuli near the oval window [E. Olson, J. Acoust. Soc. Am. 103, 3445-3463 (1998)], is principally dissipative at frequencies lower than 10 kHz. Conclusions: (a) middle-ear vibrations in adult gerbils do not limit the input to the cochlea up to at least 40 kHz, i.e., within 0.5 oct of the high-frequency cutoff of the behavioral audiogram; and (b) the results in both adult and neonatal gerbils are inconsistent with the hypothesis that mass reactance controls high-frequency ossicular vibrations and support the idea that the middle ear functions as a transmission line.
Osaki, Takako; Matsuki, Takahiro; Asahara, Takashi; Zaman, Cynthia; Hanawa, Tomoko; Yonezawa, Hideo; Kurata, Satoshi; Woo, Timothy Derg-hoong; Nomoto, Koji; Kamiya, Shigeru
Quantitative (qt) real time PCR using 16SrDNA primers is useful for determination of the bacterial composition of the gastric microbiota in Mongolian gerbils. The aim of this study was to determine the change in the gastric microbiota after long-term infection with Helicobacter pylori. One year after inoculation with H. pylori, five gerbils were determined as H. pylori-positive and 6 gerbils H. pylori-negative by culture and real time qt PCR methods. The gastric microbiota of each group of gerbils was also compared with that of 6 gerbils uninfected with H. pylori. DNA from the Atopobium cluster, Bifidobacterium spp., Clostridium coccoides group, Clostridium leptum subgroup, Enterococcus spp. and Lactobacillus spp. were detected in the gastric mucus of both infected and uninfected gerbils. In contrast, Eubacterium cylindroides group and Prevotella spp. were detected only in H. pylori-negative gerbils. The numbers of C. leptum subgroup, C. coccoides group and Bifidobacterium spp. in gastric mucus of H. pylori-negative Mongolian gerbils were significantly lower than those in non-infected gerbils. The results obtained suggest that the composition of gastric indigenous microbiota in Mongolian gerbils may be disturbed by long-term infection with H. pylori, and that these changes may in fact inhibit H. pylori infection.
Lee, Jin-Uk; Kim, Okjin
AIM: To investigate maternal H pylori infection status to determine the potential of maternal transmission. METHODS: In the present study, we examined these issues in an experimental murine model, which is a Mongolian gerbil model that has been reported as an optimal laboratory animal model to study H pylori. Pregnant Mongolian gerbils, infected experimentally with H pylori, were divided into as four groups. Following the experimental design, the stomachs of the mother and litters were isolated and assessed for transmission of H pylori at the prenatal period, parturition day, 1-wk old and 3-wk old respectively. Bacterial culture and polymerase chain reaction (PCR) were used to examine the presence of transmitted H pylori. RESULTS: All litters showed no transmission of H pylori during pregnancy and at parturition day. However, they revealed 33.3% and 69.6% at 1-wk and 3-wk of age respectively by PCR. CONCLUSION: These results suggested that vertical infection during the prenatal period or delivery procedure is unlikely as a route of mother-to-child H pylori infection. It may be that H pylori is acquired through breast-feeding, contaminated saliva and fecal-oral transmission during co-habitation. PMID:17007019
Wilkie, D M; Slobin, P
In Experiment 1 six hungry gerbils received six trials per day on a 17-arm radial maze. During each trial the subjects were allowed to choose freely among the arms, each of which contained a food pellet, until each arm had been visited once or until eight minutes had elapsed. An error was recorded when the subject entered a previously visited arm. The gerbils quickly learned not to re-enter previously visited arms and generally made errors on fewer than 15% of entries, performance comparable to that of the rat and superior to that of other species tested in the radial arm maze. The intertrial-interval duration did not affect accuracy of arm choices during acquisition but did influence asymptotic accuracy. Accuracy did not change systematically over the six trials. A high proportion of arm entries were to nearby arms. Errors occurred most often towards the end of a trial. Odor cues were not important. When the number of trials per day was reduced from six to one, accuracy deteriorated slightly. In Experiment 2 neither the transposition of extramaze cues nor the placement of the maze in a different room had large disruptive effects on accuracy. In Experiment 3 the addition of three explicit intramaze brightness cues aided accuracy, perhaps by permitting the subjects to decompose the large maze into three smaller mazes, although there was no direct evidence that this was the case. Implications of a number of these results for models of spatial maze performance were discussed. PMID:6655427
Morick, Danny; Krasnov, Boris R; Khokhlova, Irina S; Gottlieb, Yuval; Harrus, Shimon
A high prevalence of Bartonella infection is found in many natural systems; however, the transmission dynamics leading to observations of these infections is not fully understood. The capability of Xenopsylla ramesis fleas to serve as competent vectors of Bartonella sp. OE 1-1 (a strain closely related to the zoonotic Bartonella elizabethae) to Meriones crassus jirds was investigated. Naïve X. ramesis fleas were placed for 72 h on naïve jirds or jirds that were either experimentally or naturally infected with Bartonella sp. strain OE 1-1, after which they were placed on naïve jirds. Postfeeding, 69 to 100% of the fleas collected from each Bartonella-positive jird contained Bartonella DNA, and all naïve jirds became positive for Bartonella sp. OE 1-1 after infestation with the infected fleas. In addition, maternal transmission of Bartonella sp. OE 1-1 in jirds was tested by mating 5 Bartonella-positive and 5 naïve female jirds with 10 naïve male jirds in the absence of fleas. Fifteen offspring were delivered by each group. Cultures of blood drawn from all offspring on days 35 and 47 postdelivery were found to be negative for Bartonella. A single spleen sample from the offspring of a Bartonella-positive mother was found molecularly positive for Bartonella sp. OE 1-1. This study demonstrates that X. ramesis fleas are competent vectors of Bartonella sp. OE 1-1 to M. crassus jirds and indicates that maternal transmission is probably not the major transmission route from female jirds to their offspring. We suggest that the dynamics of Bartonella sp. OE 1-1 in the M. crassus jird population in nature is mostly dependent on its vectors.
Lindstrom, Nicole M; Moore, David M; Zimmerman, Kurt; Smith, Stephen A
Hamsters, gerbils, rats, and mice are presented to veterinary clinics and hospitals for prophylactic care and treatment of clinical signs of disease. Physical examination, history, and husbandry practice information can be supplemented greatly by assessment of hematologic parameters. As a resource for veterinarians and their technicians, this article describes the methods for collection of blood, identification of blood cells, and interpretation of the hemogram in mice, rats, gerbils, and hamsters.
Lindstrom, Nicole M; Moore, David M; Zimmerman, Kurt; Smith, Stephen A
Hamsters, gerbils, rats, and mice are presented to veterinary clinics and hospitals for prophylactic care and treatment of clinical signs of disease. Physical examination, history, and husbandry practice information can be supplemented greatly by assessment of hematologic parameters. As a resource for veterinarians and their technicians, this article describes the methods for collection of blood, identification of blood cells, and interpretation of the hemogram in mice, rats, gerbils, and hamsters.
Background One of the major challenges in evolutionary biology is identifying rare species and devising management plans to protect them while also sustaining their genetic diversity. However, in attempting a broad understanding of rarity, single-species studies provide limited insights because they do not reveal whether the factors that affect rare species differ from those that affect more common species. To illustrate this important concept and to arrive at a better understanding of the form of rarity characterizing the rare Gerbillus henleyi, we explored its population genetic structure alongside that of the locally common Gerbillus andersoni allenbyi. We trapped gerbils in several locations in Israel's western and inner Negev sand dunes. We then extracted DNA from ear samples, and amplified two mitochondrial sequences: the control region (CR) and the cytochrome oxidase 2 gene (CO2). Results Nucleotide diversity was low for all sequences, especially for the CR of G. a. allenbyi, which showed no diversity. We could not detect any significant population genetic structure in G. henleyi. In contrast, G. a. allenbyi's CO2 sequence showed significant population genetic structure. Pairwise PhiPT comparisons showed low values for G. henleyi but high values for G. a. allenbyi. Analysis of the species' demographic history indicated that G. henleyi's population size has not changed recently, and is under the influence of an ongoing bottleneck. The same analysis for G. a. allenbyi showed that this species has undergone a recent population expansion. Conclusions Comparing the two species, the populations of G. a. allenbyi are more isolated from each other, likely due to the high habitat specificity characterizing this species. The bottleneck pattern found in G. henleyi may be the result of competition with larger gerbil species. This result, together with the broad habitat use and high turnover rate characterizing G. henleyi, may explain the low level of differentiation
Ilyin, E A
Missions of unmanned spacecraft Foton-M2 (2005) and Foton-M3 (2007) of 16 and 12 days in duration, respectively, provided an opportunity to conduct the Russian/US experiments with snails (Helix lucorum and Helix aspera), newts (Pleurodeles waltli), geckos (Pachydactilus turneri) and microorganisms (Streptomyces lividans 66, E. coli and others). Besides, Foton-M3 carried a Russian experiment with Mongolian gerbils (Meriones unguiculatus). Objectives of the space experiments were to study the micro-g effects on the living systems' behavior, structure and functioning, post-traumatic regeneration of bone and organs, stable inheritance of plasmid pIJ 702, and melanin pigment synthesis by streptomycets. The survey paper presents the major findings of a large team of investigators.
Gustavsen, Carsten R; Kvicerova, Jana; Dickinson, Hayley; Heller, R Scott
Acomys, also called spiny mice, were once used as a diabetes model. We have recently demonstrated that the closest relatives to the Acomys, members of the family Gerbillinae, lack the transcription factor Pdx-1. Therefore, we sought to determine if members of this family also lack Pdx-1, and describe the pancreatic morphology in three different species of Acomys: Acomys cahirinus (Egyptian spiny mouse), Acomys cilicicus (Asia Minor spiny mouse) and Acomys dimidiatus (eastern spiny mouse). We successfully cloned the Acomys Pdx-1 gene and we demonstrate by immunocytochemistry that the Pdx-1 protein is expressed in the pancreatic insulin immunoreactive cells and in a subset of the somatostatin cells. The basic islet structure is very similar to other rodents - with the insulin cells in the center, and glucagon, somatostatin, PP and occasional PYY cells in the periphery. No ghrelin or CART cells were identified. Nkx6.1 was localized specifically to the insulin immunoreactive cells, while Nkx2.2 was found in all endocrine cells except the somatostatin immunoreactive cells. Both MafA and MafB were expressed in the islets; MafA being specific for the insulin cells, while MafB was primarily in the glucagon cells but also found in some insulin cells. Isl-1 was localized in all endocrine cell types. In conclusion, the closest relatives to the Gerbils express a Pdx-1 protein that is 90% similar to other rodents but also has a unique 3 amino acid insert compared to other species. During the evolution of the spiny mice and the gerbils, it appears that the Pdx-1 gene was lost.
Kuo, Chao-Hung; Yu, Fang-Jung; Tsai, Pei-Yun; Yang, Sheau-Fang; Chang, Lin-Li; Jan, Chang-Ming; Wang, Wen-Ming; Wu, Deng-Chyang
A strong correlation between Helicobacter pylori infection and gastric cancer has been reported. Mongolian gerbils are regarded as the most suitable animal model in which to study carcinogenesis associated with H. pylori. The aim of our study was to evaluate the accuracy of the serologic test for detecting H. pylori infection in Mongolian gerbils. The model was developed as follows: the H. pylori colony (vacuolating cytotoxin A (+)/cytotoxin-associated gene A (+)) was cultured from the mucosas of previously H. pylori-fed gerbils. These colonies were cultured in broth. Then,we fed the gerbils with 0.5-1 mL of broth (about 10(9) CFU/mL) (intragastric administration) twice within a 3-day period. After inoculation for 6 or 26 weeks, the gerbils were sacrificed and their gastric mucosas were sampled for a series of examinations. Blood samples for serologic testing (STAT-PAK) were collected. H. pylori infection was confirmed. Statistical analysis was performed using the Chi-square test. Differences were regarded as significant when the p value was less than 0.05. A total of 50 gerbils were inoculated with H. pylori and the success rate reached 88%. All 10 gerbils in the control group showed a negative result. Damage to the mucosas was more obvious following increasing periods of inoculation. The rates of sensitivity and specificity, as determined by the STAT-PAK test, were 90.9% and 100%, respectively. The positive and negative predictive values were 100% and 60%, respectively. The STAT-PAK test seemed to be more sensitive and accurate (p < 0.05) in high H. pylori densities. In conclusion, the STAT-PAK test (blood-sampling) showed acceptable results and was suitable for long-term observation of H. pylori infection.
Chang, Chi-Fen; Chau, Yat-Pang; Lu, Kuo-Shyan
The anterior medial gland (AMG), located in the submucosa of rodent nasal septum, is suggested to provide fluid for humidification of inspired air. Tremendous variation of the environmental air humidity, on which rats and gerbils depend to live, leads us to expect a multiplicity on ultrastructure and various subcellular glycoconjugate distribution within the AMG acinar cells between these two species. Electron microscopy revealed that: (1) The nucleus of AMG acinar cells in rat was irregular-shaped, but that in gerbil was round or elliptical; (2) Secretory granules in rat AMG acinar cells contained homogenous content with various electron density. However, two types of secretory granules in gerbil AMG acinar cells were found: one with lamellated-structure and high electron density, while the others had particulate materials; (3) Myoepithelial cells were present in the acinus of medial and posterior regions in rat AMG, but absent in gerbil; and (4) Nerve terminals were present only in the medial and posterior rat AMG, but in all three regions of the gerbil AMG. Lectin histochemistry demonstrated that: (1) Rat and gerbil AMG acinar cells expressed strong affinity toward Con A and WGA, but neither showed any reactivity toward UEA and PNA; and (2) Varying degrees of reactivity toward different lectins, including DBA, PNA, SBA and EBL, were recognized in rat and gerbil AMG acinar cells. We confirm the species variation on the ultrastructure and lectin histochemistry of AMG in rats and gerbils, and speculate that these variations may be due to the different living environment.
The interplay of homeostasis and circadian rhythmicity in the control of body temperature was studied in the fat-tailed gerbil (Pachyuromys duprasi). In a first study, the body temperature rhythm of 8 gerbils maintained at 24 degrees C under a 14L:10D light-dark cycle was studied by telemetry. Data from 9 other species of small mammals were also obtained for comparison. The gerbils were found to exhibit a robust rhythm of body temperature (the most robust of the 10 species) with a high plateau during the dark phase of the light-dark cycle and a low plateau during the light phase. In a second experiment, 5 gerbils were allowed to select the temperature of their environment by moving along a thermal gradient. The animals consistently selected higher ambient temperatures during the light phase of the light-dark cycle (when their body temperature was at the low plateau). In a third experiment, the metabolic response of 8 gerbils to an acute cold exposure was determined by indirect calorimetry. Greater cold-induced thermogenesis was observed during the light phase. The fact that the animals selected higher ambient temperatures and displayed greater cold-induced thermogenesis when their body temperature was lower contradicts the hypothesis that the body temperature rhythm is caused by a rhythmic oscillation of the thermoregulatory set point.
Wappler, Edina A; Szilágyi, Géza; Gál, Anikó; Skopál, Judit; Nyakas, Csaba; Nagy, Zoltán; Felszeghy, Klára
Transient occlusion of common carotid arteries in gerbils is a simple and widely used model for assessing histological and functional consequences of transient forebrain ischemia and neuroprotective action of pharmaceuticals. In the present study we aimed to introduce additional behavioural tests as novel object recognition and food-motivated hole-board learning in order to measure attention and learning capacity in gerbils. For validating these cognitive tests the effects of ageing (4, 9 and 18 months) and those of transient forebrain ischemia induced by bilateral carotid occlusion at 9 months of age were investigated. Neuronal cell death was estimated in the hippocampus using TUNEL and caspase-3 double fluorescence labelling and confocal microscopy. Ageing within the selected range although influenced ambulatory activity, did not considerably change attention and memory functions of gerbils. As a result of transient ischemia a selective neuronal damage in CA1 and CA2 regions of the hippocampus has been observed and tested 4 days after the insult. Ischemic gerbils became hyperactive, but showed decreased attention and impaired spatial memory functions as compared to sham-operated controls. According to our results the novel object recognition paradigm and the hole-board spatial learning test could reliably be added to the battery of conventional behavioural tests applied previously in this species. The novel tests can be performed within a wide interval of adult age and provide useful additional methods for assessing ischemia-induced cognitive impairment in gerbils.
Oh, Yun-Jung; Kim, Heung-No; Jeong, Ji-Heon; Park, Dae-Kyoon; Park, Kyung-Ho; Ko, Jeong-Sik; Kim, Duk-Soo
We investigated the temporal alterations of adrenocorticotropic hormone (ACTH) immunoreactivity in the hippocampus after seizure onset. Expression of ACTH was observed within interneurons in the pre-seizure group of seizure sensitive gerbils, whereas its immunoreactivities were rarely detected in seizure resistant gerbil. Three hr after the seizure, ACTH immunoreactivity was significantly increased in interneurons within all hippocampal regions. On the basis of their localization and morphology through immunofluorescence staining, these cells were identified as GABAA α1-containing interneurons. At the 12 hr postictal period, ACTH expression in these regions was down-regulated, in a similar manner to the pre-seizure group of gerbils. These findings support the increase in ACTH synthesis that contributes to a reduction of corticotrophin-releasing factor via the negative feedback system which in turn provides an opportunity to enhance the excitability of GABAergic interneurons. Therefore, ACTH may play an important role in the reduction of excitotoxicity in all hippocampal regions.
Robinson, Alan M.; Vujanovic, Irena; Richter, Claus-Peter
This animal study was designed to determine if minocycline ameliorates cochlear damage is caused by intratympanic injection of the ototoxic aminoglycoside antibiotic neomycin. Baseline auditory-evoked brainstem responses were measured in gerbils that received 40 mM intratympanic neomycin either with 0, 1.2, or 1.5 mg/kg intraperitoneal minocycline. Four weeks later auditory-evoked brainstem responses were measured and compared to the baseline measurements. Minocycline treatments of 1.2 mg/kg and 1.5 mg/kg resulted in significantly lower threshold increases compared to 0 mg/kg, indicating protection of hearing loss between 6 kHz and 19 kHz. Cochleae were processed for histology and sectioned to allow quantification of the spiral ganglion neurons and histological evaluation of organ of Corti. Significant reduction of spiral ganglion neuron density was demonstrated in animals that did not receive minocycline, indicating that those receiving minocycline demonstrated enhanced survival of spiral ganglion neurons, enhanced survival of sensory hairs cells and spiral ganglion neurons, and reduced hearing threshold elevation correlates with minocycline treatment demonstrating that neomycin induced hearing loss can be reduced by the simultaneous application of minocycline. PMID:25950003
Noto, Jennifer M; Romero-Gallo, Judith; Piazuelo, M Blanca; Peek, Richard M
The Mongolian gerbil is an efficient, robust, and cost-effective rodent model that recapitulates many features of H. pylori-induced gastric inflammation and carcinogenesis in humans, allowing for targeted investigation of the bacterial determinants and environmental factors and, to a lesser degree, host constituents that govern H. pylori-mediated disease. This chapter discusses means through which the Mongolian gerbil model has been used to define mechanisms of H. pylori-inflammation and cancer as well as the current materials and methods for utilizing this model of microbially induced disease.
Rocha, Fernando Allan de Farias; Gomes, Bruno Duarte; Silveira, Luiz Carlos de Lima; Martins, Sonia Limara; Aguiar, Renata Genaro; de Souza, John Manuel; Ventura, Dora Fix
A new method is presented to determine the retinal spectral sensitivity function S(λ) using the electroretinogram (ERG). S(λ)s were assessed in three different species of myomorph rodents, Gerbils (Meriones unguiculatus), Wistar rats (Ratus norvegicus), and mice (Mus musculus). The method, called AC Constant Method, is based on a computerized automatic feedback system that adjusts light intensity to maintain a constant-response amplitude to a flickering stimulus throughout the spectrum, as it is scanned from 300 to 700 nm, and back. The results are presented as the reciprocal of the intensity at each wavelength required to maintain a constant peak to peak response amplitude. The resulting S(λ) had two peaks in all three rodent species, corresponding to ultraviolet and M cones, respectively: 359 nm and 511 nm for mice, 362 nm and 493 nm for gerbils, and 362 nm and 502 nm for rats. Results for mouse and gerbil were similar to literature reports of S(λ) functions obtained with other methods, confirming that the ERG associated to the AC Constant-Response Method was effective to obtain reliable S(λ) functions. In addition, due to its fast data collection time, the AC Constant Response Method has the advantage of keeping the eye in a constant light adapted state. PMID:26800521
Du, Xiaoyan; Chen, Zhenwen; Li, Wei; Tan, Yuanqing; Lu, Jing; Zhu, Xiangdong; Zhao, Taiyun; Dong, Gang; Zeng, Lin
The objectives of this study are to establish microsatellite loci for the Mongolian gerbil based on mouse microsatellite DNA sequences and to investigate genetic variation in the laboratory gerbil (Capital Medical University, CMU) and 2 wild gerbil populations (from Yin Chuan city [YIN] and the Hohehot Municipality [HOH]). In total, 536 mouse microsatellite markers were chosen to identify polymorphic dinucleotide repeat loci in the gerbil by cross-amplification. Of these markers, 313 (58.39%) have been discretely amplified from the CMU laboratory gerbil and been sequenced. Of the 313 sequenced markers, 130 were confirmed as simple sequence repeat (SSR) loci in the gerbil. In total, 6 of those newly identified loci plus 6 identified in previous reports were used to estimate the genetic polymorphism for 30 laboratory gerbils and 54 wild gerbils (27 each of the HOH and YIN groups). A total of 29 alleles were observed in the 3 populations, and 11 of 12 loci (91.67%) are polymorphic markers. Nei's standard genetic distances of 0.0592 (CMU vs. HOH) and 0.1033 (CMU vs. YIN) were observed. The averages of observed versus expected heterozygosity are 0.5231/0.4008, 0.5051/0.3882, and 0.4825/0.3665 for the YIN, HOH, and CMU populations, respectively. These results show that cross-amplification using mouse microsatellite primers is an efficient way to identify gerbil SSR loci. By using these 12 selected markers, we have demonstrated that genetic variation level within the CMU population is higher than that has been reported previously and are comparable with the levels found in 2 wild populations.
Mikiel-Hunter, Jason; Kotak, Vibhakar; Rinzel, John
A high-frequency, subthreshold resonance in the guinea pig medial superior olive (MSO) was recently linked to the efficient extraction of spatial cues from the fine structure of acoustic stimuli. We report here that MSO neurons in gerbil also have resonant properties and, based on our whole-cell recordings and computational modeling, that a low-voltage-gated potassium current, IKLT, underlies the resonance. We show that resonance was lost following dynamic clamp replacement of IKLT with a leak conductance and in the model when voltage-gating of IKLT was suppressed. Resonance was characterized using small amplitude sinusoidal stimuli to generate impedance curves as typically done for linear systems analysis. Extending our study into the nonlinear, voltage-dependent regime, we increased stimulus amplitude and found, experimentally and in simulations, that the subthreshold resonant frequency (242Hz for weak stimuli) increased continuously to the resonant frequency for spiking (285Hz). The spike resonance of these phasic-firing (type III excitable) MSO neurons and of the model is of particular interest also because previous studies of resonance typically involved neurons/models (type II excitable, such as the standard Hodgkin-Huxley model) that can fire tonically for steady inputs. To probe more directly how these resonances relate to MSO neurons as slope-detectors, we presented periodic trains of brief, fast-rising excitatory post-synaptic potentials (EPSCs) to the model. While weak subthreshold EPSC trains were essentially low-pass filtered, resonance emerged as EPSC amplitude increased. Interestingly, for spike-evoking EPSC trains, the threshold amplitude at spike resonant frequency (317Hz) was lower than the single ESPC threshold. Our finding of a frequency-dependent threshold for repetitive brief EPSC stimuli and preferred frequency for spiking calls for further consideration of both subthreshold and suprathreshold resonance to fast and precise temporal processing
Treagust, David F.; And Others
A laboratory exercise using a gerbil is described for use in the high school biology class and in accordance with the National Science Teachers Association guidelines. The authors cite references that deal with current awareness of the moral status concerning animals. The exercise includes measurement and calculations. (SA)
Biofortification efforts have increased concentrations of bioactive compounds in carrots. Vitamin A bioefficacy and antioxidant potential of four biofortified carrot varieties [purple/orange (PO), purple/orange/red (POR), orange/red (OR) and orange (O)] were measured in Mongolian gerbils (n = 73). ...
Bae, Minkyung; Lim, Joo Weon; Kim, Hyeyoung
Helicobacter pylori (H. pylori) induced DNA damage which may be related to gastric cancer development. The DNA damage response coordinates DNA repair, cell-cycle transition, and apoptosis through activation of DNA damage response molecules. The damaged DNA is repaired through non-homologous end joining (NHEJ) or homologous recombination (HR). In the present study, we investigated the changes of HR DNA repair proteins (ataxia-telangiectasia-mutated; ATM, ATM and Rad3-related; ATR), NHEJ repair proteins (Ku70/80), cell cycle regulators (Chk1, Chk2), and apoptosis marker (p53/p-p53) were determined in H. pylori-infected Mongolian gerbils. In addition, the effect of an antioxidant N-acetylcysteine (NAC) on H. pylori-induced DNA damage response was determined to assess the involvement of oxidative stress on DNA damage of the animals infected with H. pylori. One week after intragastric inoculation with H. pylori, Mongolian gerbils were fed with basal diet with or without 3% NAC for 6 weeks. After 6 week, the expression levels of DNA repair proteins (Ku70/80, ATM, ATR), cell cycle regulators (Chk1, Chk2) and apoptosis marker (p-p53/p53) were increased in gastric mucosa of Mongolian gerbils, which was suppressed by NAC treatment. In conclusion, oxidative stress mediates H. pylori-induced DNA damage response including NHEJ and HR repairing processes, cell cycle arrest and apoptosis in gastric mucosa of Mongolian gerbils.
Kling, Melissa A
The purpose of this article is to provide for practitioners a comprehensive overview of respiratory diseases, both infectious and noninfectious, in the mouse, rat, hamster, and gerbil. The information presented will also be useful for veterinarians pursuing board certification. Anatomy and physiology are briefly addressed, as those two facets alone could encompass an entire article for these species.
Saqui-Salces, Milena; Neri-Gómez, Teresa; Gamboa-Dominguez, Armando; Ruiz-Palacios, Guillermo; Camacho-Arroyo, Ignacio
AIM: We studied the estrogen receptor (ER) and progesterone receptor (PR) isoforms expression in gastric antrum and corpus of female gerbils and their regulation by estradiol (E2) and progesterone (P4). METHODS: Ovariectomized adult female gerbils were subcutaneously treated with E2, and E2 + P4. Uteri and stomachs were removed, the latter were cut along the greater curvature, and antrum and corpus were excised. Proteins were immunoblotted using antibodies that recognize ER-alpha, ER-beta, and PR-A and PR-B receptor isoforms. Tissues from rats treated in the same way were used as controls. RESULTS: Specific bands were detected for ER-alpha (68 KDa), and PR isoforms (85 and 120 KDa for PR-A and PR-B isoforms, respectively) in uteri, gastric antrum and corpus. We could not detect ER-beta isoform. PR isoforms were not regulated by E2 or P4 in uterus and gastric tissues of gerbils. ER-alpha isoform content was significantly down-regulated by E2 in the corpus, but not affected by hormones in uterus and gastric antrum. CONCLUSION: The presence of ER-alpha and PR isoforms in gerbils stomach suggests that E2 and P4 actions in this organ are in part mediated by their nuclear receptors. PMID:18837087
Soomro, Majid Hussain; Shi, Ruihan; She, Ruiping; Yang, Yifei; Hu, Fengjiao; Li, Heng
We examined the effect of hepatitis E virus (HEV) on the renal tissue pathogenesis, morphological damages and related molecular mechanisms following swine HEV suspension intraperitoneally inoculation in Mongolian gerbils. The microscopic and ultramicroscopic analyses of kidney tissue structure were carried out at different points after inoculation of HEV. The immunohistochemistry, real-time PCR and Western blot were performed to explore the molecular mechanisms associated with HEV presence in the renal tissues. Real-time PCR revealed that the copies of HEV RNA in the kidney were detected at 7 dpi, and peaked at 14 dpi at a concentration was 7.18 logs g(-1), with detection of HEV ORF2 antigen by immunohistochemistry. Hematoxylin and eosin (HE) staining showed pathological lesions including glomerular atrophy, degeneration, edema and necrosis of renal tubular epithelial cells and Mallory and Sirius red staining indicated the presence of collagen fibers and fibrosis in kidney tissues of inoculated gerbils. Ultrastructural studies of basal membrane of renal tubules demonstrated the rough and uneven with mitochondria swelling and vacuolation in the tissues of HEV inoculated animals. Similarly, significantly higher number of (TUNEL)-positive cells were seen in renal tubule tissues compared to control group. Moreover, immuno histochemical results indicated that significant increase expression of the B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), FAS and Caspase-3 in HEV inoculated Mongolian gerbils at each time points. Relative mRNA expression by real-time PCR revealed a significantly higher (P<0.05) mRNA level of BAX, Bcl-2 and caspase-3 transcription in HEV inoculated Mongolian gerbils. Our results demonstrates that activation of mitochondria and Caspase-3 protease might be induced the apoptosis which subsequently cause the necrosis and cell death of renal epithelial cells during acute phase of HEV infection in HEV inoculated Mongolian gerbils.
Shimamura, Hideo; Hirota, Mikako; Miyazawa, Mitsuo; Kinjo, Noriko; Mineshita, Satoru
The contractile and extensile effects of red and white wine on rat and Mongolian gerbil (gerbil) gastrointestinal smooth muscle were investigated. Both wines elicited contractile responses on rat and gerbil duodenum and ileum but had no such effects on the colon or rectum. Dichloromethane extracts derived from either wine showed extensile responses only on rat duodenum and ileum, and did not elicit extensile effects on the colon or rectum. In contrast, wine dichloromethane extracts did not elicit any extensile effects on either gerbil duodenum or ileum. Moreover, dichloromethane extracts had suppressive effects on acetylcholine-induced contractile responses. Red and white wine has been documented to contain a number of organic acids such as tartaric, malic, lactic, and citric acid. Individually, such compounds evoked contractile response on rat duodenum with an order of contractile potency; citric > tartaric >or= malic > lactic acid. The abundance of such compounds in either wine implicates them as the active component responsible for gastrointestinal smooth muscle responses.
Fischer, Peter U.; Curtis, Kurt C.; Marcos, Luis A.; Weil, Gary J.
Human paragonimiasis is an emerging disease in Missouri. To characterize local parasites, we examined crayfish from three rivers. Metacercaeriae consistent with Paragonimus kellicotti were detected in 69%, 67%, and 37% of crayfish from the Big Piney, Huzzah, and Black Rivers, respectively. Sequencing of the second internal transcribed spacer and other DNA markers confirmed the species identification and the presence of identical parasite sequences in clinical specimens from two human cases. Mongolian gerbils were infected by intraperitoneal injection with 3–8 metacercariae. Most gerbils died 15–49 days post-infection. Necropsies showed pulmonary hemorrhage with necrosis, and flukes as long as 8 mm were recovered from intrathoracic tissues. Western blot analysis using P. kellicotti antigen showed a strong antibody response in gerbils 39 days post-infection. These results demonstrate that P. kellicotti is common in Missouri crayfish. The gerbil model may be useful for research on the pathogenesis, immunology, and treatment of paragonimiasis. PMID:21633042
Bleich, A; Köhn, I; Glage, S; Beil, W; Wagner, S; Mähler, M
The Mongolian gerbil is an excellent animal model for Helicobacter pylori-induced gastritis in humans. In this study, initially low colonization rates of the H. pylori strains ATCC 43504, SS1, or HP87 inoculated into gerbils caused difficulties in establishing this model. In order to increase the colonization ability and pathogenicity, the clinical HP87 isolate was selected for adaptation to the gerbil stomach by multiple in vivo passages through gerbils. Development of gastritis was examined histologically at 4-52 weeks after infection. The proportion of gerbils which tested positive for H. pylori by culture at four weeks after inoculation gradually increased from 11.1% of gerbils inoculated with HP87 without prior in vivo passage (P0) to 100% of gerbils inoculated with HP87 with seven in vivo passages (P7). In addition, adaptation of HP87 resulted in more severe histopathological changes. Gerbils infected with adapted HP87 (P7) exhibited severe infiltration by monomorphonuclear and polymorphonuclear leukocytes in the mucosa, submucosa, and subserosa of the gastric antrum, as well as epithelial changes consisting of hyperplasia, erosion, and ulceration. Histopathological changes increased in severity from four to 52 weeks after infection. Adaptation of HP87 during its passages through gerbils could be due to genetic changes in bacterial colonization factors. Identification of these changes might be useful to understand the underlying mechanism of gastric adaptation and pathogenesis of H. pylori.
Varty, Geoffrey B; Morgan, Cynthia A; Cohen-Williams, Mary E; Coffin, Vicki L; Carey, Galen J
Several neurokinin NK1 receptor antagonists currently being developed for anxiety and depression have reduced affinity for the rat and mouse NK1 receptor compared with human. Consequently, it has proven difficult to test these agents in traditional rat and mouse models of anxiety and depression. This issue has been overcome, in part, by using non-traditional lab species such as the guinea pig and gerbil, which have NK1 receptors closer in homology to human NK1 receptors. However, there are very few reports describing the behavior of gerbils in traditional models of anxiety. The aim of the present study was to determine if the elevated plus-maze, a commonly used anxiety model, could be adapted for the gerbil. Using a specially-designed elevated plus-maze, gerbils exhibited an 'anxious' behavioral profile similar to that observed in rats and mice, i.e., reduced entries into, and time spent exploring, an open, aversive arm. The anxiolytic drugs diazepam (0.03-3 mg/kg i.p.), chlordiazepoxide (0.3-10 mg/kg i.p.), and buspirone (0.3-30 mg/kg s.c.) increased open arm exploration and produced anxiolytic-like effects on risk-assessment behaviors (reduced stretch-attend postures and increased head dips). Of particular interest, the antidepressant drugs imipramine (1-30 mg/kg p.o.), fluoxetine (1-30 mg/kg, p.o.) and paroxetine (0.3-10 mg/kg p.o.) each produced some acute anxiolytic-like activity, without affecting locomotor activity. The antipsychotic, haloperidol, and the psychostimulant, amphetamine, did not produce any anxiolytic-like effects (1-10 mg/kg s.c). The anxiogenic beta-carboline, FG-7142, reduced time spent in the open arm and head dips, and increased stretch-attend postures (1-30 mg/kg, i.p.). These studies have demonstrated that gerbils exhibit an anxiety-like profile on an elevated plus-maze, and that the gerbil elevated plus-maze may have predictive validity for anxiolytics, and antidepressants with potential anxiolytic-like effects.
Frazão-Teixeira, Edwards; de Oliveira, Francisco Carlos Rodrigues; Fiuza, Vagner Ricardo da Silva; Jiménez-Sanz, Amanda Lucía; Detmann, Edenio
The impact of Cystoisospora felis infection on the nutritional efficiency of gerbils was studied. The variables weight gain and feed intake were measured during four weeks in 28 laboratory gerbils, of which 14 were inoculated with 3.5 × 10(5) sporulated oocysts of C. felis and the remaining 14 were controls. The animals from both groups were weighted, killed, eviscerated and had their carcasses and tissues weighted and compared. A modern tool designed for measuring nutritional performance of farm animals was applied. The results showed compromised nutritional efficiency of the infected animals within the first week after infection. The consequences of these results are discussed here, including the potential impact of infection on farm animals performance.
Semiane, Nesrine; Foufelle, Fabienne; Ferré, Pascal; Hainault, Isabelle; Ameddah, Souad; Mallek, Aicha; Khalkhal, Ali; Dahmani, Yasmina
A high intake of sugars has been linked to diet-induced health problems. The aim of this study was to assess whether the long-term consumption of a high-carbohydrate diet (HCD) would cause the hepatic histopathological and metabolic abnormalities that characterize nonalcoholic steatohepatitis (NASH) in a desert gerbil, Gerbillus gerbillus. Compared to natural diet, HCD leads to several metabolic disorders including adiposity, dyslipidemia, insulin resistance, ectopic fat deposition in the liver, which were associated with higher levels of transcripts of genes involved with fat synthesis, endoplasmic reticulum (ER) stress, and fibrosis. In the same way, the experimented animals showed enhanced oxidative stress. Taken together, these results demonstrate that HCD consumption in gerbils induces metabolic disorders and damaged liver, which are key contributors to NASH development. These results suggest that this rodent represents a valuable natural model for human diet-induced metabolic disorders and nonalcoholic fatty liver disease (NAFLD).
Musacchia, X. J.
Bioenergetic studies on hamsters during depressed metabolic states are reported. External support of blood glucose extended the survival times of hibernating animals. Radioresistance increased in hibernating as well as in hypothermic hamsters. Marked changes in hamster catecholamine turnover rates were observed during acclimatization to high temperature stress. High radioresistance levels of the gerbil gastrointestinal system were attributed in part to the ability of the gut to maintain functional integrity.
Gea, Stefan L R; Decraemer, Willem F; Funnell, W Robert J; Funnell, Robert W J; Dirckx, Joris J J; Maier, Hannes
The middle ear is too complex a system for its function to be fully understood with simple descriptive models. Realistic mathematical models must be used in which structural elements are represented by geometrically correct three-dimensional (3D) models with correct physical parameters and boundary conditions. In the past, the choice of boundary conditions could not be based on experimental evidence as no clear-cut data were available. We have, therefore, studied the deformation of the tympanic membrane (TM) at its boundaries using X-ray microscopic computed tomography in human and gerbil while static pressure was applied to the ear canal. The 3D models of the TM and its bony attachments were carefully made and used to measure the deformation of the TM with focus on the periphery and the manubrium attachment. For the pars flaccida of the gerbil, the boundary condition can, for the most part, be described as simply supported. For the human pars flaccida, the situation is more complicated: superiorly, the membrane contacts the underlying bone more and more when pushed further inward, and it gradually detaches from the wall when sucked outward. In gerbil, the attachment of the TM to the manubrium can be described as simply supported. In human, the manubrium is attached underneath the TM via the plica mallearis and the contact of the TM with the bone is indirect. For both human and gerbil, a simple boundary condition for the peripheral edge of the pars tensa is not appropriate due to the intricate structure at the edge: the TM thickens rapidly before continuing into the annulus fibrosis which finally makes contact with the bone.
Elgot, Abdeljalil; El hiba, Omar; Gamrani, Halima
Dehydration is a powerful stimulus causing disequilibrium in homeostasis of water and electrolytes resulting from depletion in total body water. Most studies have focused on domestic and laboratory animals; however, the study of desert animals allows improved understanding about water balance and resistance to dehydration and associated behavioral changes, including those related to mood disorders. Meriones shawi (Shaw's Jird) is a desert rodent characterized by its resistance to long periods of thirst that can extend for several months. In the present study, M. shawi were subjected to water deprivation for 1 and 3 months. We used 5-HT immunohistochemistry to evaluate the effects of prolonged dehydration on the serotoninergic system in both dorsal and median raphe nuclei (DRN, MRN), which are the main sources of 5-HT input to several brain areas. In addition, a dark/light box was used to evaluate the anxiolytic-like or anxiogenic-like effects of dehydration on M. shawi. The results showed a reduction in the 5-HT immunolabelling in both DRN and MRN following 1 and 3 months of dehydration. This diminution of serotonin immunoreactivity was accompanied by noticeable changes in anxiety behavior of Meriones, with animals spending more time in the light box, suggesting anxiogenic-like effects caused by dehydration. Overall, the results indicate that dehydration is able to reduce serotoninergic neurotransmission, which might be involved in generating anxiety behavior in this desert animal.
Olson, Merle E; Heine, Josef
The objectives of the study were to determine the optimal dose of febantel, pyrantel embonate and a combination of febantel/pyrantel embonate required to effectively treat Giardia in a gerbil model and to determine if there is a synergistic effect with the two drugs. SPF gerbils were infected by oral inoculation with 105 Giardia duodenalis trophozoites (day 0). On days 5 to 7, animals (n = 6) were treated once daily via oral gavage with febantel, pyrantel embonate, febantel and pyrantel embonate, metronidazole or placebo. Gerbils were euthanised 24 hours after last treatment and duodenal trophozoites were enumerated on a haemocytometer to obtain a concentration of trophozoites/ cm of gut. Febantel alone, effectively eliminated Giardia trophozoites at 160 and 80 mg/kg. Pyrantel embonate did not eliminate Giardia from the animals but significantly reduced parasite counts at all dosages. Febantel combined with pyrantel embonate effectively eliminated Giardia trophozoites at 160, 80 and 40 mg/kg. Metronidazole did not eliminate Giardia trophozoites from the gut. All placebo-treated animals were heavily infected with Giardia trophozoites. It can be concluded that febantel is more effective in elimination of Giardia infections when combined with pyrantel embonate compared to the agents used alone.
Lv, Lin; Wang, Yapei; Feng, Weili; Hernandez, Jorge A; Huang, Wanyi; Zheng, Yuxiang; Zhou, Xue; Lv, Shumei; Chen, Yajun; Yuan, Zi-Guo
The aim of our study was to detect differentially regulated proteins and specific signaling pathways in Mongolian gerbil brains during chronic Toxoplasma gondii (T.gondii) PRU strain infection. We use a iTRAQ-based strategy to detecte 4935 proteins, out of which 110 proteins were differentially expressed (>/=2.0-fold, p value <0.05) when the brain of gerbils infected with T.gondii was compared to control brain tissues. We confirmed the authenticity and the accuracy of iTRAQ results through quantitative real-time PCR and western blot (WB), which was consistent with mass spectrometry analysis. Pathway analysis and GO (Gene Ontology) annotations indicated the deregulation of several pathways related to immune response, metabolism and neurological processes, like neuronal growth and neurotransmitter transport. Through the iTRAQ-based strategy, we obtained a comparative proteome profile of brain tissues from Mongolian gerbils with chronic infection of T.gondii. Several differentially expressed proteins involved in neurological pathways, like Parvalbumin, Drebrin or Synaptotagmin, can be further investigated to enhance our understanding of central nervous system (CNS) injury caused by T.gondii.
Yamada, Takanori; Wei, Min; Toyoda, Takeshi; Yamano, Shoutaro; Wanibuchi, Hideki
Helicobacter pylori (H. pylori) infection is well known to be associated with chronic gastritis and also development of gastric cancer. Raphanobrassica (RB) is an intergeneric hybrid of the genera Raphanus (radish) and Brassica (cabbages) containing appreciable amounts of glucoraphanin (GR) and glucoraphenin (GRe), which are actively hydrolyzed by the enzyme myrosinase to sulforaphane and sulforaphene, respectively. Both of these metabolites exert antimicrobial and anti-inflammatory activity. The purpose of the present study was to investigate the effect of two freeze-dried products of RB (RB1 and RB2) on H. pylori-induced gastritis in Mongolian gerbils. Six-week-old male Mongolian gerbils were inoculated orally with H. pylori (ATCC 43504), and 2weeks later were fed diets containing no additives or diets supplemented with 2% RB1 (containing both GR and GRe) or 2% RB2 (containing GR only) for 10weeks. In the RB1, but not the RB2 group, mononuclear cell infiltration, mRNA expression of IL-6, and cell proliferation in the gastric mucosa were significantly suppressed. These results indicate that RB1 containing both GR and GRe exerted significant inhibitory effects on H. pylori-induced gastritis in Mongolian gerbils apparently mediated via suppression of IL-6 expression and chronic inflammation.
Klinge, Astrid; Klump, Georg
By applying a Go/NoGo paradigm, thresholds for detecting mistuning of components of a 200 Hz complex were determined in the Mongolian gerbil and compared with thresholds obtained in a previous study with an 800 Hz complex. Frequency difference limens (FDLs) for detecting mistuning decreased with increasing harmonic frequency and harmonic number (0.5% to 0.01% Weber fraction). It was furthermore examined how starting and ending the mistuned component earlier than the remaining complex affects the FDL (duration of all components 400 ms, time shift 30 to 500 ms). Large FDLs that are similar to pure tone FDLs (between 21% and 6.7%) were found for onset asynchronies of 300 ms and more, indicating separate processing of the mistuned component. Small FDLs that are similar to FDLs of the synchronous condition were found if the temporal overlap between the mistuned component and the remaining complex was 100 ms or more. These experimental data in combination with a simulation of processing of the harmonic complexes by the gerbil's peripheral auditory filters led to the conclusion that the phase and amplitude modulations in the filter outputs can provide cues that allow gerbils a sensitive detection of mistuning across a wide range of frequencies.
Otsubo, K; Katayama, Y; Kashiwagi, F; Muramatsu, H; Terashi, A
The effects of glycerol and mannitol, as well as urea, on delayed neuronal death (DND) in the gerbil hippocampus were investigated. 20% solution of glycerol, mannitol and urea were prepared, and 6.5 ml/kg of each agent, or saline, was administered to male Mongolian gerbils intraperitoneally 30 min before ischemia. The animals were subjected to transient forebrain ischemia for 5 min. Seven days after the ischemic insult, the brains were fixed and stained for histopathological analysis. The number of normal neurons (neuronal density, ND) in a 1 mm linear length of hippocampal CA1 region was counted. ND of sham-operated group (n = 6) was 275.3 +/- 16.7 (mean +/- SD). ND in the saline-treated group (n = 6) was 14.8 +/- 5.0. ND of groups treated with glycerol (n = 6), mannitol (n = 6) and urea (n = 4) was 68.2 +/- 56.7 (p < 0.01), 52.8 +/- 54.4 (p < 0.01) and 12.0 +/- 2.5 (NS), respectively. The present study demonstrates that glycerol and mannitol have some protective effects against DND in the gerbil hippocampus, whereas urea has no effect.
Bradley, B F; Starkey, N J; Brown, S L; Lea, R W
Lavender is a popular treatment for stress and mild anxiety in Europe and the USA. The present study investigated the effects of (Lavandula angustifolia Mill. (Lamiaceae)) lavender odour inhalation over 2 weeks or 24 h periods, on gerbil behaviour in the elevated plus maze in mature male and female gerbils, and compared results with the effects of diazepam (1 mg/kg) i.p. after 30 min and 2-week administration. Traditional measures of open entries showed an increasing trend over the 2 weeks exposure, whereas ethological measures indicative of anxiety; stretch-attend frequency and percentage protected head-dips, were significantly lower. Exploratory behaviour, total head-dip frequency, increased after 24 h lavender and 2 weeks exposure. These results are comparable with diazepam administration. There were sex differences in protected head-dip an ethological indicator of anxiety: females showed a significant decrease in protected head-dips compared to both males and to female controls. In conclusion exposure to lavender odour may have an anxiolytic profile in gerbils similar to that of the anxiolytic diazepam. In addition, prolonged, 2-week lavender odour exposure increased exploratory behaviour in females indicating a further decrease in anxiety in this sex.
Ravicz, Michael E; Cooper, Nigel P; Rosowski, John J
Middle-ear sound transmission was evaluated as the middle-ear transfer admittance H(MY) (the ratio of stapes velocity to ear-canal sound pressure near the umbo) in gerbils during closed-field sound stimulation at frequencies from 0.1 to 60 kHz, a range that spans the gerbil's audiometric range. Similar measurements were performed in two laboratories. The H(MY) magnitude (a) increased with frequency below 1 kHz, (b) remained approximately constant with frequency from 5 to 35 kHz, and (c) decreased substantially from 35 to 50 kHz. The H(MY) phase increased linearly with frequency from 5 to 35 kHz, consistent with a 20-29 micros delay, and flattened at higher frequencies. Measurements from different directions showed that stapes motion is predominantly pistonlike except in a narrow frequency band around 10 kHz. Cochlear input impedance was estimated from H(MY) and previously-measured cochlear sound pressure. Results do not support the idea that the middle ear is a lossless matched transmission line. Results support the ideas that (1) middle-ear transmission is consistent with a mechanical transmission line or multiresonant network between 5 and 35 kHz and decreases at higher frequencies, (2) stapes motion is pistonlike over most of the gerbil auditory range, and (3) middle-ear transmission properties are a determinant of the audiogram.
Selaković, Vesna; Rauš Balind, Snežana; Radenović, Lidija; Prolić, Zlatko; Janać, Branka
The aim of study was to investigate the effects of extremely low frequency magnetic field (ELF-MF; 50 Hz; 0.1, 0.25 and 0.5 mT) on oxidative stress in the brain of 3- (adult) and 10-month-old (middle-aged) gerbils. Nitric oxide (NO) level, superoxide (O2(-)) production, superoxide dismutase (SOD) activity, and index of lipid peroxidation (ILP) were measured in the forebrain cortex, striatum, hippocampus, and cerebellum immediately and 3 days after cessation of 7-day exposure. In all gerbils, ELF-MF significantly increased oxidative stress in all tested brain regions. This effect was correlated with the value of magnetic induction and was higher in middle-aged gerbils. Three days after cessation of exposure, the values of examined parameters were closer to control levels. In adult gerbils, the effect of ELF-MF of 0.1 mT on NO level, O2(-) production and SOD activity was almost fully disappeared, and ILP was at the control level regardless of the value of magnetic induction. In middle-aged gerbils, the effect of ELF-MF was still present but to a lesser degree than those observed immediately after cessation of exposure. These findings pointed out the ability of ELF-MF to induce age- and magnetic induction-dependent modification of oxidative stress in the brain.
Kim, Ji-Eun; Kwak, Sung-Eun; Choi, Hui-Chul; Song, Hong-Ki; Kim, Yeong-In; Jo, Seung-Mook; Kang, Tae-Cheon
In the present study, we investigated the distribution of voltage-gated Na(+) channels (VGSCs) in the normal and epileptic hippocampus of gerbils (a genetic epilepsy model) in order to confirm the relationship between VGSC and seizure activity in these animals. There was no difference of VGSC I immunoreactivity in the hippocampus between seizure-resistant (SR) and seizure sensitive (SS) gerbils. VGSC II immunoreactivity was rarely detected in the perikarya of principal neurons and interneurons in the SR gerbil hippocampus. However, in the SS gerbil hippocampus, VGSC II immunoreactivity was densely observed in the somata of interneurons located in the stratum radiatum and stratum lacunosum-moleculare. Double immunofluorescent study showed immunoreactivity for calretinin (approximately 80% in VGSC II-positive neurons) or calbindin D-28k (approximately 20% in VGSC II-positive neurons) in VGSC II-immunoreactive neurons. VGSC II-immunoreactive neurons did not show parvalbumin immunoreactivity. These findings suggest that seizure activity in SS gerbils may be related to the selective hyperactivation of interneurons in stratum lacunosum-moleculare via the up-regulation of VGSC II expression, which leads to the disinhibition of CA1 pyramidal cells.
Wallace-Boone, Tanya L; Newton, Amy E; Wright, Robert N; Lodge, Nicholas J; McElroy, John F
Several studies have suggested that neurokinin-1 (NK1) receptor antagonists may have therapeutic potential as novel antidepressant drugs. To test these compounds preclinically, gerbils have become one of the preferred species in that they demonstrate close NK1 receptor homology with humans and bind NK1 antagonists with higher affinity than rats and mice. The intent of the present study was to determine whether the forced-swim test (FST), one of the most commonly used animal tests of antidepressant-like activity, could be adapted for use with the gerbil. Critical factors in the establishment of this assay included swim tank diameter, weight, and sex of the animals tested. Pharmacological validation of the FST using standard antidepressant compounds (eg fluoxetine, paroxetine, desipramine) resulted in decreased immobility time during the test, indicative of an antidepressant-like effect. Similar to results reported for the rat and mouse FST, the antipsychotic drug haloperidol increased immobility, whereas the psychostimulant, amphetamine decreased immobility, and anxiolytic drugs (eg buspirone) had no effect. Investigation into the locomotor effects of all compounds tested was consistent with previous reports in other species, with the exception of paroxetine, which produced hyperactivity at therapeutically effective doses in gerbils. In addition to standard antidepressants, NK1 antagonists (L-733060, MK-869, and CP-122721) all reduced immobility in the gerbil FST without affecting locomotor activity. Overall, these results suggest that the gerbil is an ideal species for use in the FST, and that this paradigm may have predictive validity for identifying novel antidepressant compounds.
Mason, Matthew J
Anatomists and zoologists who study middle ear morphology are often interested to know what the structure of an ear can reveal about the auditory acuity and hearing range of the animal in question. This paper represents an introduction to middle ear function targetted towards biological scientists with little experience in the field of auditory acoustics. Simple models of impedance matching are first described, based on the familiar concepts of the area and lever ratios of the middle ear. However, using the Mongolian gerbil Meriones unguiculatus as a test case, it is shown that the predictions made by such 'ideal transformer' models are generally not consistent with measurements derived from recent experimental studies. Electrical analogue models represent a better way to understand some of the complex, frequency-dependent responses of the middle ear: these have been used to model the effects of middle ear subcavities, and the possible function of the auditory ossicles as a transmission line. The concepts behind such models are explained here, again aimed at those with little background knowledge. Functional inferences based on middle ear anatomy are more likely to be valid at low frequencies. Acoustic impedance at low frequencies is dominated by compliance; expanded middle ear cavities, found in small desert mammals including gerbils, jerboas and the sengi Macroscelides, are expected to improve low-frequency sound transmission, as long as the ossicular system is not too stiff.
Macedo, Iara Tersia Freitas; Oliveira, Lorena Mayana Beserra de; Ribeiro, Wesley Lyeverton Correia; Santos, Jessica Maria Leite dos; Silva, Kaline das Chagas; Araújo Filho, José Vilemar de; Camurça-Vasconcelos, Ana Lourdes Fernandes; Bevilaqua, Claudia Maria Leal
Parasitic nematodes are of major economic importance in livestock. An alternative for the control of parasites is phytotherapy. This study evaluated the efficacy of Cymbopogon citratus decoction (CcD), C. citratus essential oil (CcEo) and citral against Haemonchus contortus using in vitro egg hatch test (EHT) and larval development test (LDT) and an in vivo test using a Meriones unguiculatus (gerbil) model. The effect of 800 mg/kg CcEo was evaluated in gerbils that had been artificially infected with 5,000 third-stage H. contortus larvae. The effective concentrations required to inhibit 50% (EC50) of egg hatching were 0.46, 0.14 and 0.13 mg/mL for CcD, CcEo and citral, respectively. The EC50 values in the LDT were 5.04, 1.92 and 1.37 mg/mL for CcD, CcEo and citral, respectively. H. contortus population in the group treated with C. citratus essential oil was reduced by 38.5% (P< 0.05) in comparison to the control group. These results suggest that it may be possible to use C. citratus essential oil to control of H. contortus parasite of small ruminant.
Marti, E; Blasi, J; Ferrer, I
The expression of secretogranin-II and its major proteolytic product secretoneurin (SN) is under the control of neuronal excitation, as demonstrated by treating rats with the excitotoxic kainic acid (KA). Differences in the structure and function of the hippocampus in rats and gerbils have been described; these suggest possible differential reactive responses to KA. In the present study, the SN immunostaining pattern in relation with cell damage is analyzed from 6 h to 4 days following KA administration in rats and gerbils. Dramatic differences in the expression of SN were found in the hippocampal complex following KA administration in gerbils and rats. A robust increase in SN immunoreactivity was detected in the pyramidal cell layer of the rat hippocampus, especially in the CA1 area. In the gerbil, however, a strong increase in SN immunostaining was detected in interneurons of the hippocampal formation, as shown by double-labeling immunohistochemistry to SN and the calcium-binding proteins parvalbumin, calbindin, and calretinin. In addition, no damage (in the hippocampal formation) or moderate damage (in the entorhinal cortex) was observed in the gerbil, in contrast to the rat. The administration of KA and the GABA-B receptor inhibitors (CGP56999A or CGP36742) to the gerbil resulted in a strong rise in SN immunoreactitivty in the CA1 pyramidal cell layer of the hippocampus, as in the rat. However, no increased cell damage was observed under these conditions. The present data provide evidence of a species-differential reactive response to KA that might be based, in part, on distinct inhibitory intrahippocampal circuitry.
Roulo, Rebecca M.; Fishburn, Jillian D.; Amosu, Mayowa; Etchison, Ashley R.
Listeria monocytogenes is a food-borne pathogen that can result in adverse pregnancy outcomes, such as stillbirth or premature delivery. The Mongolian gerbil was recently proposed as the most appropriate small-animal model of listeriosis due to its susceptibility to the same invasion pathways as humans. The objectives of this study were to investigate invasion and adverse pregnancy outcomes in gerbils orally exposed to L. monocytogenes, to compare the dose-response data to those of other animal models, and to investigate differences in the responses of pregnant versus nonpregnant gerbils. Gerbils were orally exposed to 0 (control), 103, 105, 107, or 109 CFU L. monocytogenes in whipping cream. L. monocytogenes was recovered in a dose-dependent manner from fecal samples, adult organs, and pregnancy-associated tissues. Dams exposed to 109 CFU had more invaded organs and higher concentrations of L. monocytogenes in almost all organs than nonpregnant animals, though no differences in fecal shedding were seen between the two groups. Adverse pregnancy outcomes occurred only in the dams treated with 109 CFU. A 50% infectivity dose (ID50) of 2.60 × 106 CFU for fetuses was calculated by fitting the data to a logistic model. Our results suggest that the 50% lethal dose (LD50) falls within the range of 5 × 106 to 5 × 108 CFU. This range includes the guinea pig and nonhuman primate LD50s, but the observation that L. monocytogenes-induced stillbirths can be seen in guinea pigs and primates exposed to lower doses than those at which stillbirths were seen in gerbils indicates that gerbils are not more sensitive to L. monocytogenes invasion. PMID:25156729
Roulo, Rebecca M; Fishburn, Jillian D; Amosu, Mayowa; Etchison, Ashley R; Smith, Mary Alice
Listeria monocytogenes is a food-borne pathogen that can result in adverse pregnancy outcomes, such as stillbirth or premature delivery. The Mongolian gerbil was recently proposed as the most appropriate small-animal model of listeriosis due to its susceptibility to the same invasion pathways as humans. The objectives of this study were to investigate invasion and adverse pregnancy outcomes in gerbils orally exposed to L. monocytogenes, to compare the dose-response data to those of other animal models, and to investigate differences in the responses of pregnant versus nonpregnant gerbils. Gerbils were orally exposed to 0 (control), 10(3), 10(5), 10(7), or 10(9) CFU L. monocytogenes in whipping cream. L. monocytogenes was recovered in a dose-dependent manner from fecal samples, adult organs, and pregnancy-associated tissues. Dams exposed to 10(9) CFU had more invaded organs and higher concentrations of L. monocytogenes in almost all organs than nonpregnant animals, though no differences in fecal shedding were seen between the two groups. Adverse pregnancy outcomes occurred only in the dams treated with 10(9) CFU. A 50% infectivity dose (ID50) of 2.60 × 10(6) CFU for fetuses was calculated by fitting the data to a logistic model. Our results suggest that the 50% lethal dose (LD50) falls within the range of 5 × 10(6) to 5 × 10(8) CFU. This range includes the guinea pig and nonhuman primate LD50s, but the observation that L. monocytogenes-induced stillbirths can be seen in guinea pigs and primates exposed to lower doses than those at which stillbirths were seen in gerbils indicates that gerbils are not more sensitive to L. monocytogenes invasion.
Zhao, Xue-Yan; Wu, Chun-Fang; Yang, Jun; Gao, Yang; Sun, Fang-Jie; Wang, Da-Xin; Wang, Chang-Hong; Lin, Bao-Cheng
Brain edema formation is one of the most important mechanisms of ischemia-evoked cerebral edema. It has been demonstrated that arginine vasopressin (AVP) receptors are involved in the pathophysiology of secondary brain damage after focal cerebral ischemia. In a well-characterized animal model of ischemic stroke of Mongolian gerbils, the present study was undertaken to clear the effect of AVP on cortex edema in cerebral ischemia. The results showed that (1) occluding the left carotid artery of Mongolian gerbils not only decreased the cortex specific gravity (cortex edema) but also increased AVP levels in the ipsilateral cortex (ischemic area) including left prefrontal lobe, left parietal lobe, left temporal lobe, left occipital lobe and left hippocampus for the first 6 hours, and did not change of the cortex specific gravity and AVP concentration in the right cortex (non-ischemic area); (2) there were many negative relationships between the specific gravity and AVP levels in the ischemic cortex; (3) intranasal AVP (50 ng or 200 ng), which could pass through the blood-brain barrier to the brain, aggravated the focal cortex edema, whereas intranasal AVP receptor antagonist-D(CH2)5Tyr(ET)DAVP (2 µg) mitigated the cortex edema in the ischemic area after occluding the left carotid artery of Mongolian gerbils; and (4) either intranasal AVP or AVP receptor antagonist did not evoke that edema in the non-ischemic cortex. The data indicated that AVP participated in the process of ischemia-evoked cortex edema, and the cerebral AVP receptor might serve as an important therapeutic target for the ischemia-evoked cortex edema.
Al-Rousan, Rabaa M; Manzoor, Kamran; Paturi, Satyanarayana; Arvapalli, Ravi Kumar; Laurino, Joseph P; Darnon, Lucy; Walker, Ernest M; Blough, Eric R
Iron-induced cardiovascular disease is the leading cause of death in iron-overloaded patients. Deferasirox is a novel tridentate oral chelator that exhibits a half-life suitable for once-daily dosing; however, little is known regarding the effectiveness of this agent in preventing iron-induced cardiovascular disease. Adult male Mongolian gerbils were randomly divided into 3 groups: control, iron overload, and iron overload followed by deferasirox treatment. Iron-overloaded animals received iron dextran 100 mg/kg intraperitoneally (ip)/5 days for 10 weeks, while deferasirox was given 100 mg/kg per d orally (po) for 9 months post iron loading. Cardiac and aortic iron levels were determined by inductively coupled plasma atomic emission spectrometry. Gerbil electro- and echocardiograms were obtained in anesthetized animals at regular intervals. Compared to control animals, iron concentration was 3.3- and 2.4-fold higher in iron-overloaded heart and aorta, respectively (P < .05). Deferasirox treatment reduced cardiac and aortic iron levels by 32% and 35%, respectively (P < .05). These results were consistent with the decrease in cellular iron deposition observed with Prussian Blue iron staining. Iron-overloaded gerbils were found to exhibit frequent arrhythmias including premature ventricular contractions, supraventricular tachycardia, and recurrent ventricular tachycardia. In addition, echocardiographic assessment demonstrated iron overload-associated increase in left ventricular dimensions including left ventricular posterior wall dimension (LVPWd: 49%), left ventricular internal dimension (LVIDd: 26%), and left ventricular septum thickness (LVSd: 42%). These parameters were significantly reduced with deferasirox treatment (LVPWd: 23%, LVIDd: 24%, and LVSd: 27%). Iron overload was also associated with reduced ejection fraction (EF: by 30%) and fractional shortening (FS: by 23%) in comparison with controls (P < .05). With deferasirox treatment, these values were higher
Järbe, T U; Ohlin, G C
Open-field activity and rectal temperature were measured in mongolian gerbils treated with alcholol (1 and 2 g/kg) only and when alcohol was combined with bemegride (20 and 40 mg/kg), DH-524 (20 mg/kg), or d-amphetamine (8 mg/kg). None of the purported antagonists normalized the alcholol-produced changes in the open-field test, nor did they reverse the alcohol-induced hypothermia. However, alcohol offered protection against bemegride-induced convulsion and death. When compared with pervious data (1) it is suggested that alcohol is differentiated from pentobarbital and diazepam on the basis of their interactional effects with bemegride.
Ten Ham, M; Loskota, W J; Lomax, P
Beta9-THC was injected daily for 6 days into gerbils from our breeding colony that exhibit spontaneous epileptiform seizures. At a dose of 20 mg/kg no effect was seen on the latency, duration or severity of the seizures induced after 1 and 6 days of treatment. Delta9-THC (50 mg/kg) completely abolished the seizures after a single injection but tolerance developed to this effect so that no protection was afforded after 6 daily doses. Severe toxic signs were evident at the higher dose level with marked depression of spontaneous motor activity. The toxic effect increased progressively with chronic treatment and half the animals failed to survive.
Embar, Keren; Mukherjee, Shomen; Kotler, Burt P
In predator-prey foraging games, predators should respond to variations in prey state. The value of energy for the prey changes depending on season. Prey in a low energetic state and/or in a reproductive state should invest more in foraging and tolerate higher predation risk. This should make the prey more catchable, and thereby, more preferable to predators. We ask, can predators respond to prey state? How does season and state affect the foraging game from the predator's perspective? By letting owls choose between gerbils whose states we experimentally manipulated, we could demonstrate predator sensitivity to prey state and predator selectivity that otherwise may be obscured by the foraging game. During spring, owls invested more time and attacks in the patch with well-fed gerbils. During summer, owls attacked both patches equally, yet allocated more time to the patch with hungry gerbils. Energetic state per se does not seem to be the basis of owl choice. The owls strongly responded to these subtle differences. In summer, gerbils managed their behavior primarily for survival, and the owls equalized capture opportunities by attacking both patches equally.
Randall, Jan A.; McCowan, Brenda; Collins, Kellie C.; Hooper, Stacie L.; Rogovin, Konstantin
The great gerbil, Rhombomys opinus, is a highly social rodent that usually lives in family groups consisting of related females, their offspring, and an adult male. The gerbils emit alarm vocalizations in the presence of diverse predators with different hunting tactics. Alarm calls were recorded in response to three predators, a monitor lizard, hunting dog, and human, to determine whether the most common call type, the rhythmic call, is functionally referential with regard to type of predator. Results show variation in the alarm calls of both adults and subadults with the type of predator. Discriminant function analysis classified an average of 70% of calls to predator type. Call variation, however, was not limited to the predator context, because signal structure also differed by sex, age, individual callers, and family groups. These variations illustrate the flexibility of the rhythmic alarm call of the great gerbil and how it might have multiple functions and communicate in multiple contexts. Three alarm calls, variation in the rhythmic call, and vibrational signals generated from foot-drumming provide the gerbils with a varied and multi-channel acoustic repertoire.
Rauš, Snežana; Selaković, Vesna; Radenović, Lidija; Prolić, Zlatko; Janać, Branka
The purpose of this study was to evaluate behavioural effects of an extremely low frequency magnetic field (ELF-MF) in 3-month-old Mongolian gerbils submitted to global cerebral ischemia. After 10-min occlusion of both common carotid arteries, the gerbils were placed in the vicinity of an electromagnet and continuously exposed to ELF-MF (50Hz, 0.5mT) for 7 days. Their behaviour (locomotion, stereotypy, rotations, and immobility) was monitored on days 1, 2, 4, 7, and 14 after reperfusion for 60min in the open field. It was shown that the 10-min global cerebral ischemia per se induced a significant motor activity increase (locomotion, stereotypy and rotations), and consequently immobility decrease until day 4 after reperfusion, compared to control gerbils. Exposure to ELF-MF inhibited development of ischemia-induced motor hyperactivity during the whole period of registration, but significantly in the first 2 days after reperfusion, when the postischemic hyperactivity was most evident. Motor activity of these gerbils was still significantly increased compared to control ones, but only on day 1 after reperfusion. Our results revealed that the applied ELF-MF (50Hz, 0.5mT) decreased motor hyperactivity induced by the 10-min global cerebral ischemia, via modulation of the processes that underlie this behavioural response.
Kotler, Burt P; Brown, Joel; Mukherjee, Shomen; Berger-Tal, Oded; Bouskila, Amos
Foraging animals have several tools for managing the risk of predation, and the foraging games between them and their predators. Among these, time allocation is foremost, followed by vigilance and apprehension. Together, their use influences a forager's time allocation and giving-up density (GUD) in depletable resource patches. We examined Allenby's gerbils (Gerbilus andersoni allenbyi) exploiting seed resource patches in a large vivarium under varying moon phases in the presence of a red fox (Vulpes vulpes). We measured time allocated to foraging patches electronically and GUDs from seeds left behind in resource patches. From these, we estimated handling times, attack rates and quitting harvest rates (QHRs). Gerbils displayed greater vigilance (lower attack rates) at brighter moon phases (full < wane < wax < new). Similarly, they displayed higher GUDs at brighter moon phases (wax > full > new > wane). Finally, gerbils displayed higher QHRs at new and waxing moon phases. Differences across moon phases not only reflect changing time allocation and vigilance, but changes in the state of the foragers and their marginal value of energy. Early in the lunar cycle, gerbils rely on vigilance and sacrifice state to avoid risk; later they defend state at the cost of increased time allocation; finally their state can recover as safe opportunities expand. In the predator-prey foraging game, foxes may contribute to these patterns of behaviours by modulating their own activity in response to the opportunities presented in each moon phase.
Jeong, Mi-Jin; Jeon, Chang-Jin
Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are involved in circadian rhythm and pupil responses. The purpose of this study was to reveal the organization of melanopsin-immunoreactive (IR) neurons in the Mongolian gerbil retina using immunocytochemistry. Melanopsin-IR cells were primarily located in the ganglion cell layer (GCL; M1c; 75.15%). Many melanopsin-IR cells were also observed in the inner nuclear layer (INL; M1d; 22.28%). The M1c and M1d cell types extended their dendritic processes into the OFF sublayer of the inner plexiform layer (IPL). We rarely observed bistratified cells (M3; 2.56%) with dendrites in both the ON and OFF sublayers of the IPL. Surprisingly, we did not observe M2 cells which are well observed in other rodents. Melanopsin-IR cell somas were small to medium in size and had large dendritic fields. They had 2-5 primary dendrites that branched sparingly and had varicosities. Melanopsin-IR cell density was very low: they comprised 0.50% of the total ganglion cell population. Moreover, none of the melanopsin-IR cells expressed calbindin-D28K, calretinin, or parvalbumin. These results suggest that in the Mongolian gerbil, melanopsin-IR cells are expressed in a very small RGC subpopulation, and are independent of calcium-binding proteins-containing RGCs.
Lipets, E N; Ponomareva, E V; Ogneva, I V; Vikhliantsev, I M; Karaduleva, E V; Kratashkina, N L; Kuznetsov, S L; Podlubnaia, Z A; Shenkman, B S
The work had the goal to compare the microgravity effects on gerbil's muscles-antagonists, m. soleus and m. tibialis anterior. The animals were exposed in 12-d space microgravity aboard Earth's artificial satellite "Foton-M3". Findings of the analysis of single skinned fibers contractility are 19.7% diminution of the diameter and 21.8% loss of the total contractive force of m. soleus fibers post flight. However, there was no significant difference in calcium sensitivity which agrees with the absence of changes in the relative content of several major cytoskeletal proteins (titin and nebulin ratios to heavy chains of myosin were identical in the flight and control groups) and a slight shifting of the myosin phenotype toward the "fast type" (9%, p < 0.05). These parameters were mostly unaffected by the space flight in m. tibialis anterior. To sum up, the decline of contractility and diminution of gerbil's myofibers after the space flight were less significant as compared with rats and did not impact the sytoskeletal protein ratios.
Decraemer, W. F.; Khanna, S. M.; Olson, E. S.
Recent measurements of three-dimensional stapes motion in gerbil indicated that the piston component of stapes motion was the primary contributor to intracochlear pressure. In order to make a detailed correlation between stapes piston motion and intracochlear pressure behind the stapes, simultaneous pressure and motion measurements were undertaken. We found that the scala vestibuli pressure followed the piston component of the stapes velocity with high fidelity, reinforcing our previous finding that the piston motion of the stapes was the main stimulus to the cochlea. The present data allowed us to calculate cochlear input impedance and power flow into the cochlea. Both the amplitude and phase of the impedance were quite flat with frequency from 3 kHz to at least 30 kHz, with a phase that was primarily resistive. With constant stimulus pressure in the ear canal the intracochlear pressure at the stapes has been previously shown to be approximately flat with frequency through a wide range, and coupling that result with the present findings indicates that the power that flows into the cochlea is quite flat from about 3 to 30 kHz. The observed wide-band intracochlear pressure and power flow are consistent with the wide-band audiogram of the gerbil. PMID:18459001
Rhee, Chung-Ku; Bae, Sung Huyn; Chang, So-Young; Chung, Phil-Sang; Jung, Jae-Yun
Aim: to investigate effectiveness of Low level laser therapy (LLLT) in rescueing ouabain induced spiral ganglion cell damage using Mongolian gerbils. Methods: Animals were divided into 3 groups; Control, Ouabain, Ouabain + LLLT group. Auditory neuropathy was induced by topical application of ouabain (1 mmol/L, 3uL) on the round window membrane in gerbils. Transmeatal LLLT was irradiated into the right ear for 1h (200mW, 720 J) daily for 7d in Ouabain + LLLT group. Before and 7 days after ouabain application, hearing was evaluated using both ABR and distortion product otoacoustic emissions (DPOAE). Seven days after ouabain application, animals were sacrificed to evaluate the morphological changes of cochlea using cochlear section image and whole mount Immunofluorescent staining. Results: DPOAE tests were normal in all animals after ouabain topical treatment indicating intact outer hair cells. Ouabain group showed ABR threshold increase compared with control group. Ouabain+LLLT group showed significant improvement of ABR threshold compared to ouabain only group. H and E stains of mid-modiolar section of cochlear showed spiral ganglion cells, neurofilaments, and post synaptic receptor counts were decreased while inner and outer hair cells were preserved in ouabain group. Ouabain +LLLT group showed higher numbers of spiral ganglion cells, density of neurofilaments and post synaptic receptor counts compared to ouabain group. Conclusions: The results demonstrated that LLLT was effective to rescue ouabain-induced spiral ganglion neuropathy.
Pentón-Rol, Giselle; Marín-Prida, Javier; Pardo-Andreu, Gilberto; Martínez-Sánchez, Gregorio; Acosta-Medina, Emilio Felino; Valdivia-Acosta, Alain; Lagumersindez-Denis, Nielsen; Rodríguez-Jiménez, Efraín; Llópiz-Arzuaga, Alexey; López-Saura, Pedro Antonio; Guillén-Nieto, Gerardo; Pentón-Arias, Eduardo
Although the huge economic and social impact and the predicted incidence increase, neuroprotection for ischemic stroke remains as a therapeutically empty niche. In the present study, we investigated the rationale of the C-Phycocyanin (C-PC) treatment on global cerebral ischemia/reperfusion (I/R) injury in gerbils. We demonstrated that C-PC given either prophylactically or therapeutically was able to significantly reduce the infarct volume as assessed by triphenyltetrazolium chloride (TTC) staining and the neurological deficit score 24h post-stroke. In addition, C-PC exhibited a protective effect against hippocampus neuronal cell death, and significantly improved the functional outcome (locomotor behavior) and gerbil survival after 7 days of reperfusion. Malondialdehyde (MDA), peroxidation potential (PP) and ferric reducing ability of plasma (FRAP) were assayed in serum and brain homogenates to evaluate the redox status 24h post-stroke. The treatment with C-PC prevented the lipid peroxidation and the increase of FRAP in both tissue compartments. These results suggest that the protective effects of C-PC are most likely due to its antioxidant activity, although its anti-inflammatory and immuno-modulatory properties reported elsewhere could also contribute to neuroprotection. To our knowledge, this is the first report of the neuroprotective effect of C-PC in an experimental model of global cerebral I/R damage, and strongly indicates that C-PC may represent a potential preventive and acute disease modifying pharmacological agent for stroke therapy.
Acute dependence on a single dose of morphine in mice, rats and gerbils was assessed by observing several signs of abstinence precipitated by various doses of naloxone, diprenorphine and Mr 2097. In mice and rats acutely dependent on morphine, naloxone, diprenorphine and Mr 2097 precipitated dose-dependently the signs of abstinence such as jumping, urination, teeth chattering, chewing, paw shakes, head shakes and ptosis. In these two species, the precipitation of these signs were mediated by stereospecific opiate receptors, as Mr 2096, the non-antagonistic isomer of Mr 2097, did not precipitate any of them. In gerbils acutely dependent on morphine, naloxone precipitated urination, teeth chattering, chewing, paw shakes, head shakes, "wet dog" shakes, yawning and writhing. In naive animals of all three species, the opioid antagonists produced varying degrees of "abstinoid" signs. The precipitated withdrawal might be the result of "abstinoid" effects superimposed on real abstinence signs. High doses of naloxone and diprenorphine showed a regression of "abstinoid" signs probably because of interfering morphinomimetic properties. The present data indicate that these three rodents may be successfully employed in the rapid identification of drugs to produce morphine-like dependence or to precipitate withdrawal.
Schmid, B V; Jesse, M; Wilschut, L I; Viljugrein, H; Heesterbeek, J A P
Speculation on how the bacterium Yersinia pestis re-emerges after years of absence in the Prebalkhash region in Kazakhstan has been ongoing for half a century, but the mechanism is still unclear. One of the theories is that plague persists in its reservoir host (the great gerbil) in so-called hotspots, i.e. small regions in which the conditions remain favourable for plague to persist during times where the conditions in the Prebalkhash region as a whole have become unfavourable for plague persistence. In this paper we use a metapopulation model that describes the dynamics of the great gerbil. With this model we study the minimum size of an individual hotspot and the combined size of multiple hotspots in the Prebalkhash region that would be required for Y. pestis to persist through an inter-epizootic period. We show that the combined area of hotspots required for plague persistence is so large that it would be unlikely to have been missed by existing plague surveillance. This suggests that persistence of plague in that region cannot solely be explained by the existence of hotspots, and therefore other hypotheses, such as survival in multiple host species, and persistence in fleas or in the soil should be considered as well.
Ravicz, Michael E.; Cooper, Nigel P.; Rosowski, John J.
Middle-ear sound transmission was evaluated as the middle-ear transfer admittance HMY (the ratio of stapes velocity to ear-canal sound pressure near the umbo) in gerbils during closed-field sound stimulation at frequencies from 0.1 to 60 kHz, a range that spans the gerbil’s audiometric range. Similar measurements were performed in two laboratories. The HMY magnitude (a) increased with frequency below 1 kHz, (b) remained approximately constant with frequency from 5 to 35 kHz, and (c) decreased substantially from 35 to 50 kHz. The HMY phase increased linearly with frequency from 5 to 35 kHz, consistent with a 20–29 μs delay, and flattened at higher frequencies. Measurements from different directions showed that stapes motion is predominantly pistonlike except in a narrow frequency band around 10 kHz. Cochlear input impedance was estimated from HMY and previously-measured cochlear sound pressure. Results do not support the idea that the middle ear is a lossless matched transmission line. Results support the ideas that (1) middle-ear transmission is consistent with a mechanical transmission line or multiresonant network between 5 and 35 kHz and decreases at higher frequencies, (2) stapes motion is pistonlike over most of the gerbil auditory range, and (3) middle-ear transmission properties are a determinant of the audiogram. PMID:18646983
Lee, Sang-Hak; Ko, Il-Gyu; Kim, Sung-Eun; Hwang, Lakkyong; Jin, Jun-Jang; Choi, Hyun-Hee; Kim, Chang-Ju
Cerebral ischemia is caused by reduced cerebral blood flow due to a transient or permanent cerebral artery occlusion. Ischemic injury in the brain leads to neuronal cell death, and eventually causes neurological impairments. Cordyceps, the name given to the fungi on insects, has abundant useful natural products with various biological activities. Cordyceps is known to have nephroprotective, hepatoprotective, anti-inflammatory, antioxidative, and antiapoptotic effects. We investigated the effects of Cordyceps on short-term memory, neuronal apoptosis, and cell proliferation in the hippocampal dentate gyrus following transient global ischemia in gerbils. For this study, a step-down avoidance test, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, immunohistochemistry for caspase-3 and 5-bromo-2′-de-oxyuridine, and western blot for Bax, Bcl-2, brain-derived neurotrophic factor (BDNF), and tyrosin kinase B were performed. In the present study, Cordyceps alleviated cerebral ischemia-induced short-term memory impairment. Cordyceps showed therapeutic effects through inhibiting cerebral ischemia-induced apoptosis in the hippocampus. Cordyceps suppressed cerebral ischemia-induced cell proliferation in the hippocampal dentate gyrus due to the reduced apoptotic neuronal cell death. Cordyceps treatment also enhanced BDNF and TrkB expressions in the hippocampus of ischemic gerbils. It can be suggested that Cordyceps overcomes cerebral ischemia-induced neuronal apoptosis, thus facilitates recovery following cerebral ischemia injury. PMID:27162767
Lee, Sang-Hak; Ko, Il-Gyu; Kim, Sung-Eun; Hwang, Lakkyong; Jin, Jun-Jang; Choi, Hyun-Hee; Kim, Chang-Ju
Cerebral ischemia is caused by reduced cerebral blood flow due to a transient or permanent cerebral artery occlusion. Ischemic injury in the brain leads to neuronal cell death, and eventually causes neurological impairments. Cordyceps, the name given to the fungi on insects, has abundant useful natural products with various biological activities. Cordyceps is known to have nephroprotective, hepatoprotective, anti-inflammatory, antioxidative, and antiapoptotic effects. We investigated the effects of Cordyceps on short-term memory, neuronal apoptosis, and cell proliferation in the hippocampal dentate gyrus following transient global ischemia in gerbils. For this study, a step-down avoidance test, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, immunohistochemistry for caspase-3 and 5-bromo-2'-de-oxyuridine, and western blot for Bax, Bcl-2, brain-derived neurotrophic factor (BDNF), and tyrosin kinase B were performed. In the present study, Cordyceps alleviated cerebral ischemia-induced short-term memory impairment. Cordyceps showed therapeutic effects through inhibiting cerebral ischemia-induced apoptosis in the hippocampus. Cordyceps suppressed cerebral ischemia-induced cell proliferation in the hippocampal dentate gyrus due to the reduced apoptotic neuronal cell death. Cordyceps treatment also enhanced BDNF and TrkB expressions in the hippocampus of ischemic gerbils. It can be suggested that Cordyceps overcomes cerebral ischemia-induced neuronal apoptosis, thus facilitates recovery following cerebral ischemia injury.
Plahta, W C; Clark, D L; Colbourne, F
Pretreatment with 17beta-estradiol attenuates ischemia-induced hippocampal cornu ammonis 1 (CA1) neuronal death. We assessed whether this is mediated through prevention of hyperthermia that normally follows ischemia in gerbils. Male gerbils were given sustained-released 17beta-estradiol pellets or sham operation. Later, a guide cannula was implanted for brain temperature measurement and some were implanted with core temperature telemetry probes. Gerbils were subjected to either 5 min bilateral carotid artery occlusion or sham procedures 2 weeks after pellet surgery. Brain temperature was normothermic during surgery in all cases. In experiment 1, only core temperature was measured afterward in untreated and estrogen-treated gerbils. In experiment 2, postischemic core temperature was measured in untreated and two estrogen-treated ischemic groups, one of which had their postischemic temperature increased, via infrared lamp, to mimic the untreated group. Habituation was assessed on days 5 and 6. Hyperthermia, like that which occurs spontaneously, was forced on untreated and estrogen-treated ischemic animals in the third experiment, where brain temperature was measured. CA1 cell counts were assessed after a 7-day survival. A fourth experiment measured brain and core temperature simultaneously in normal gerbils during heating with an infrared lamp. Estrogen did not affect core temperature of non-ischemic gerbils whereas spontaneous postischemic hyperthermia was blocked. Estrogen reduced cell death and provided behavioral protection when gerbils regulated their own core temperature, but not when core hyperthermia was enforced. Conversely, estrogen reduced cell death in gerbils that had their brain temperature elevated. Experiment 4 showed that the brain becomes overheated (by approximately 1 degree C) when core temperature is elevated. Accordingly, estrogen likely failed to reduce CA1 injury in experiment 2, when core hyperthermia was enforced, because of overheating the
Vollenweider, Florence; Herrmann, Martina; Otten, Uwe; Nitsch, Cordula
Ischemia results in increased interleukin-6 (IL-6) expression in the brain. To prove a connection between IL-6 upregulation and IL-6 receptor (IL-6R) expression following ischemia, we analyzed cell-type specific expression changes of IL-6R using transient global ischemia in the gerbil as a model. In sham operated animals, IL-6R mRNA and protein were mainly detected in hippocampal pyramidal cells and interneurons. After ischemia, IL-6R was expressed in neurons but there was no increase during the peak IL-6 expression. Neuronal IL-6R mRNA and protein decreased in parallel with pyramidal cell death, starting 2 days after ischemia. Double-labeling experiments revealed that in postischemic hippocampus IL-6R was not present in GFAP-reactive astrocytes but that the surviving parvalbumin containing interneurons expressed IL-6R mRNA.
Taylor, D H; Morris, D L; Reffin, D; Richards, K S
The efficacy of albendazole (50 mg/kg/d), mebendazole (50 mg/kg/d) and praziquantel (500 mg/kg/d) against established intraperitoneal infections of Echinococcus multilocularis in gerbils was compared by monitoring parasite weight and making ultrastructural observations on treated and untreated material. Praziquantel was the most active protoscolicidal agent, reducing protoscolex viability to less than 2%, although it did not inhibit cyst growth. Albendazole was the most effective agent in reducing cyst growth and was, when compared with other regimes significantly more effective than mebendazole (p less than 0.05), praziquantel (p less than 0.01) or untreated controls (p less than 0.01). Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:2583567
Dickman, J. D.; Angelaki, D. E.; Correia, M. J.
The responses from isolated single otolith afferent fibers were obtained to small angle sinusoidal pitch and roll tilts in anesthetized gerbils. The stimulus directions that produced the maximum (response vector) and minimum response sensitivities were determined for each otolith afferent, with response vectors for the units being spread throughout the horizontal plane, similar to those reported for other species. A breadth of tuning measure was derived, with narrowly tuned neurons responding maximally to stimulation in one direction and minimally along an orthogonal ('null') direction. Most (approximately 80%) otolith afferents are narrowly tuned, however, some fibers were broadly tuned responding significantly to stimulations in any direction in the horizontal plane. The number of broadly tuned otolith afferents (approximately 20%) differs significantly from the more substantial number of broadly tuned vestibular nuclei neurons (88%) recently reported in rats.
Kia, Eshrat Beigom
Echinococcus multilocularis, the small fox tapeworm, has an extensive geographical range in the northern hemisphere where foxes and small rodents represent natural hosts. The larval stage of this parasite, alveolar echinococcosis (AE), is an emerging zoonosis of increasing importance. It is a serious human illness which is often misdiagnosed as hepatic cancer. If not identified at an early stage of parasite development it can lead to the death of patients. Histological examination of biopsies is one of the classical methods of diagnosis. In this study, in order to gain unequivocal histopathological diagnosis of AE, the immunoperoxidase staining technique was performed on routinely processed histological sections of an experimentally infected gerbil, using rabbit anti-E. multilocularis protoscolex IgG labelled with horseradish peroxidase. Demonstration of AE antigen was achieved by dark brown stain of cyst membranes against a blue background of the host liver cells stained with hematoxylin.
Sabry, I; Al-Azemi, M; Al-Ghaith, L
The Harderian gland is a large orbital structure. Several functions have been ascribed to the gland such as lubrication of the eye, a source of pheromones, thermoregulartory lipids and photoprotective secretions and a part of the retinal-pineal axis. In the present study, the Harderian gland of the Cheesman's gerbil, Gerbillus cheesmani, is described for the first time. The gland is located around the posterior portion of the eyeball. The gland is compound tubular, surrounded by a thin connective tissue capsule. Only one secretory epithelial cell type was recognized, characterized by the presence of lipid vacuoles and cytoplasmic slashes in high numbers; the former being more concentrated towards the apical part while the latter being more concentrated towards the central and basal parts. Some of the cytoplasmic slashes contained electron dense filamentous structures. Similar structures were observed in the lipid vacuoles. Thus, a functional relationship between the cytoplasmic slashes and the lipid vacuoles is suggested. A unique structure was observed, termed dome-like cells, located between the epithelial cells and the basement membrane. These cells were characterized by the extensive presence of pleomorphic mitochondria and compact lamellae of granular endoplasmic reticulum (GER) in the form of finger prints. The gland was found to be actively secreting porphyrins as well as lipids. Cellular debris was also seen in the tubular lumina. Myoepithelial cells with their spindle shape and elongated nuclei were evident between the basement membrane and the secretory epithelium. Sparse interstitial tissue was observed in-between the gland tubules of both male and female gerbils. Macrophages, dendritic melanocytes and lymphocytes are the most represented cellular components of the interstitium. Further studies are required to investigate the function of the dome-like cells as well as the role of lymphocytes in the rodents Harderian gland.
Ogneva, Irina V; Kurushin, Vsevolod A; Altaeva, Erzhena G; Ponomareva, Elena V; Shenkman, Boris S
Gravitational unloading leads to destructive changes in the structure and function of muscle fibers. However, the role of the EMG activity level is still unclear. We measured changes caused by one- and three-day hypogravity in the following muscles: Soleus (Sol), Tibialis anterior (TA) and Gastrocnemius c.m. (MG). We used Wistar rats and Mongolian gerbils. The following parameters were assessed: the specific force of contraction of isolated fibers by tensometry, the transverse stiffness of the contractile apparatus by atomic force microscopy, and the calcium content by Fluo-4. We detected the accumulation of calcium ions in all muscles even after one-day unloading. In Sol this effect was more significant than in other muscles. After one-day of hypogravity we detected an increase in the specific force in all muscle types and species. Meanwhile, the transverse stiffness of the contractile apparatus, M-band and Z-disc increased only in fast muscles but not in Sol. After three-days of unloading, the specific force in Sol decreased, and the transverse stiffness of the contractile apparatus behaved in the same way as the force. The specific tension of fast muscle fibers decreased significantly in comparison with one-day unloading. In addition, the transverse stiffness of some areas of MG had a tendency to decrease in comparison to "one-day" unloading, although there was no such a tendency in the fibers of TA. In Mongolian gerbils the tendencies were the same as in the rats, but showed less dramatic changes. The reduction in the magnitude of changes in the Sol-MG-TA series correlates with EMG activity.
Pan, Qian; Li, Min; Shi, Yao-Long; Liu, Huwei; Speakman, John R; Wang, De-Hua
Mongolian gerbils (Meriones unguiculatus) have high physiological flexibility in response to acute temperature changes, and have the widest thermoneutral zone (TNZ, 26.5-38.9 °C) reported among small mammals. At the upper critical temperature (T(uc), 38.9 °C), body temperatures of gerbils were significantly increased (39-41 °C) while metabolic rates were maintained at the basal level. In contrast, below the lower critical temperature (T(lc), 26.5 °C), metabolism was elevated and body temperature stable. Rapid changes in mitochondrial membrane lipidome were hypothesized to play an important role during acute thermoregulation of gerbils. Taking advantage of a recent lipidomic technique, we examined changes in the membrane phospholipids environment and free fatty acids (FFA) production in mitochondria between 38 and 27 °C (in the TNZ), and between 27 and 16 °C (below the TNZ). At 38 °C, acute heat stress elicited distinct remodeling in mitochondrial membrane lipidome which related to a potential decrease in mitochondrial respiration and membrane fluidity compared to 27 °C. At 16 °C, a sharply decreased unsaturation index and increased chain lengths were detected in mitochondrial FFA production both in muscle and brown adipose tissue. Our results suggest that mitochondrial membrane lipid remodeling may stabilize membrane function and activity of respiration related membrane protein to maintain a stable metabolic rate at T(uc), and improve heat production by decomposing less fluid fatty acid conjugates of membrane lipids under acute cold exposure. These data therefore imply an important role of membrane remodeling during acute thermoregulation in a non-hibernating endotherm.
ZAREI, Zabiholah; MOHEBALI, Mehdi; HEIDARI, Zahra; DAVOODI, Jaber; SHABESTARI, Afshin; MOTEVALLI HAGHI, Afsaneh; KHANALIHA, Khadijeh; KIA, Eshrat Beigom
Background: Rodents have important role as reservoirs of different parasites. The aim of this study was to determine helminth parasites of abundant rodents in Meshkin-Shahr, Ardabil Province northwest Iran. Methods: From April 2014 to March 2015; 205 rodents including 118 Meriones persicus, 63 Mus musculus and 24 Cricetulus migratorius were collected, using live traps. All rodents were dissected and their different tissues examined for infectivity with helminth parasites. Results: Overall, 74.2% of rodents were infected with helminth parasites. The rate of infectivity in M. persicus, M. musculus and C. migratorius was 82.2%, 61.9%, 66.7%, respectively. In general, among all 205 rodents, the species and infection rates of helminthes were as follows: Nematoda: Trichuris sp. (46.8%), Capillaria hepatica (18.1%), Syphacia frederici (14.2%), Aspicularis tetraptera (3.4%), Trichuris rhombomidis (2%), Heligmosomom sp. (2%), Streptopharagus kuntzi (0.5%), Spiruridae gen. sp. (0.5%); Cestoda: Hymenolepis nana fraterna (16.6%) Hymenolepis diminuta (7.3%) tetratiridium of Mesocestoides sp. (1%), Paranoplocephala sp. (0.5%), Cysticercus fasciolaris (0.5%), Taenia endothoracicus larva (0.5%), and Acanthocephala: Moniliformis moniliformis (18.5%). Conclusions: Variable species of helminthes circulate in the rodents of the study area. Presence of several zoonotic species highlights the potential risk of infections for public health. PMID:28096855
Miyawaki, Takahiro; Yokota, Hidenori; Oguro, Keiji; Kato, Kengo; Shimazaki, Kuniko
In normal gerbils, intracellular zinc ions ([Zn2+]i) and calcium ions ([Ca2+]i) accumulate in hippocampal CA1 neurons after global ischemia. We examined whether ischemic preconditioning modifies these changes in gerbil hippocampal slices. In normal slices, large increases in [Zn2+]i and [Ca2+]i were observed in the stratum radiatum of the CA1 area after oxygen-glucose deprivation. In preconditioned slices, there were significantly decreased peak levels of [Zn2+]i and [Ca2+]i in CA1. However, there were no differences in the peak levels of these ions in CA3 and dentate gyrus. These results suggest that modified [Zn2+]i and [Ca2+]i accumulation after an ischemic insult might be important for the mechanisms of ischemic tolerance induced by preconditioning.
Blum, S L; Balsiger, D; Ricci, J S; Spiegel, D K
Comparisons were made between male and female gerbils reared by ventral gland-excised and intact patents. Repeated measurements before and after puberty failed to reveal an effect of gland odor exposure on body weight, ventral gland size, open-field defecation, and time of vaginal opening. Exposed animals were more attracted than nonexposed animals to a strange male's gland odor during preference tests involving "marked" and "unmarked" paper strips. Opposite-sex pairs of exposed animals engaged in more social behavior than did nonexposed pairs, but there was no difference in fighting frequency or, during extended cohabiitation, in fecundity. While early exposure to gland odor apparently does not affect physical maturation, it may enhance later responsiveness to stimuli (gland odors) that are useful in locating conspecifics and that facilitate social interactions between previously unacquainted gerbils.
Yang, Yifei; Shi, Ruihan; She, Ruiping; Soomro, Majid Hussain; Mao, Jingjing; Du, Fang; Zhao, Yue; Liu, Can
Previous studies have shown that hepatitis E virus (HEV) can be transmitted between rats, pigs, cattle, rabbits, chicken, cats, and deer. Because wild and domestic rodents have anti-HEV antibodies, they are considered potential reservoirs of HEV. In the current study, Mongolian gerbils were experimentally infected with swine hepatitis E virus and the effects of this infection were investigated. After inoculation with HEV, the liver-to-body weight ratio increased at 7 dpi. Mongolian gerbils demonstrated significant increase (p<0.05) in Aspartate Transaminase (AST), alanine transaminase (ALT) and total bilirubin (T-BIL) concentrations in the sera, and HEV IgG was detected at 21 days post-inoculation (dpi). Real-time PCR revealed that the copies of HEV RNA in the liver were detected at 7 dpi, and peaked at 28 dpi at a concentration of 7.73 logs g(-1). Using both light and electron microscopy, hepatic lesions were observed in the HEV inoculated animals. In the experimental group, characteristic viral hepatitis lesions were prominent in the liver. HEV antigen was detected in the liver by immunohistochemistry, and HEV ORF3 antigen was detectable in liver by Western blot. These results clearly demonstrate that viral load of HEV in livers was dynamic, and ultrastructural hepatic injury in HEV infected Mongolian gerbils and anti-HEV IgG positive seroconversion were observed during infection.
Wasserberg, G.; Kotler, B.P.; Morris, D.W.; Abramsky, Z.
Background: An optimal habitat selection model called centrifugal community organization (CCO) predicts that species, although they have the same primary habitat, may co-exist owing to their ability to use different secondary habitats. Goal: Test the predictions of CCO with field experiments. Species: The Egyptian sand gerbil (40 g), Gerbillus pyramidum, and Allenby's gerbil (25 g), G. andersoni allenbyi. Site: Ashdod sand dunes in the southern coastal plain of Israel. Three sandy habitats are present: shifting, semi-stabilized, and stabilized sand. Gerbils occupied all three habitats. Methods: We surveyed rodent abundance, activity levels, and foraging behaviour while experimentally removing G. pyramidum. Results: Three predictions of the CCO model were supported. Both species did best in the semi-stabilized habitat. However, they differed in their secondary habitats. Gerbillus pyramidum preferred the shifting sand habitat, whereas G. a. allenbyi preferred the stabilized habitat. Habitat selection by both species depended on density. However, in contrast to CCO, G. pyramidum dominated the core habitat and excluded G. a. allenbyi. We term this variant of CCO, 'asymmetric CCO'. Conclusions: The fundamental feature of CCO appears valid: co-existence may result not because of what each competing species does best, but because of what they do as a back-up. But in contrast to the prediction of the original CCO model, all dynamic traces of interaction can vanish if the system includes interference competition. ?? 2007 Gideon Wasserberg.
Kondo, F; Kondo, Y; Makino, H; Ogawa, N
Hyperglycemia worsens ischemic-induced neuronal damage. Many reports argue the delayed neuronal cell death (DND) after forebrain ischemia in gerbils is due to apoptosis. We examined the effects of hyperglycemia and indomethacin on DND after forebrain ischemia in gerbils. Complete occlusion of both common carotid arteries was performed for 3.5 min followed by declamping and reperfusion. Blood glucose levels were maintained at 25-30 mmol/1 for 24 h after reperfusion in the hyperglycemic groups. We examined morphological changes consistent with DND using Nissel-stained sections and DNA fragmentation using TUNEL staining, at 12, 24, 36, 48, 60, 72, 84, 96, 108, 120 h, and 7 days after reperfusion. DND was noted 96-120 h after ischemia in normoglycemic group. Hyperglycemia enhanced the development of DND at an earlier stage (48-84 h after ischemia). TUNEL positive neurons were detected 72-108 h after reperfusion in normoglycemic group, but very few TUNEL positive neurons were detected in hyperglycemic group at 36-48 h. Indomethacin reduced the number of TUNEL-positive cells in normoglycemia and completely inhibited the appearance of TUNEL-positive cells under hyperglycemia. The number of viable neurons at 7 days after ischemia was markedly higher in indomethacin-treated groups than vehicle-treated group. Our results indicate that hyperglycemia worsens DND after forebrain ischemia in gerbils but such process is not associated with DNA fragmentation. Our results also showed that indomethacin provides a neuroprotective effect in normo- and hyperglycemic conditions.
Li, Zhenkun; Huo, Xueyun; Zhang, Shuangyue; Lu, Jing; Li, Changlong; Guo, Meng; Fu, Rui; He, Zhengming; Du, Xiaoyan; Chen, Zhenwen
Deformities in the Circle of Willis (CoW) can significantly increase the risk of cerebrovascular disease in humans. However, the molecular mechanisms underlying these deformities have not been understood. Based on our previous studies, variations in the CoW of gerbils are hereditary. A normal CoW is observed in approximately 60% of gerbils, a percentage that also applies to humans. Thus, gerbil is an ideal experimental model for studying variations in the CoW. To study the mechanisms underlying these variations, we selected genes associated with different types of the CoW using suppression subtractive hybridization (SSH). After evaluating the efficiency of SSH using quantitative real-time polymerase chain reaction (qPCR) on subtracted and unsubtracted cDNA and Southern blotting on SSH PCR products, 12 SSH libraries were established. We identified 4 genes (CST3, GNAS, GPx4 and PFN2) associated with variations in the CoW. These genes were identified with qPCR and Western blotting using 70 expressed sequence tags from the SSH libraries. Cloning and sequencing allowed us to demonstrate that the 4 genes were closely related to mouse genes. We may assume that these 4 genes play an important role in the development of variations in the CoW. This study provides a foundation for further research of genes related to development of variations in the CoW and the mechanisms of dysmorphosis of cerebral vessels.
Cao, Donghui; Jiang, Jing; You, Lili; Jia, Zhifang; Tsukamoto, Tetsuya; Cai, Hongke; Wang, Shidong; Hou, Zhen; Suo, Yue-er; Cao, Xueyuan
18β-Glycyrrhetinic acid (GRA), a major component of Glycyrrhiza glabra, is widely used therapeutically in clinic. In this study, the effect of GRA on Helicobacter pylori- (H. pylori-) infected gastritis was investigated in Mongolian gerbils in vivo. The gerbils were randomly divided into groups: uninfected; H. pylori-infected; H. pylori + antibiotics (clarithromycin, amoxicillin, and esomeprazole); and H. pylori + GRA. The gastric intraluminal pH value, histopathological changes, and the expression levels of inflammation-related cytokines (IL-1β, TNF-α, COX-2, and iNOS) were investigated. The results showed that, in the H. pylori + GRA group, the intraluminal gastric pH value was lower (2.14 ± 0.08 versus 3.17 ± 0.23, P < 0.05), erosion and hyperplasia were alleviated, the infiltration of neutrophils and mononuclear cells was attenuated (P < 0.05), and the expression levels of TNF-α, IL-1β, COX-2, and iNOS were decreased (P < 0.05) compared with the H. pylori-infected group. There was no significant difference in results between the H. pylori + GRA group and the H. pylori + antibiotics group. This study indicated that GRA significantly attenuated H. pylori-infected gastritis in gerbils and has the potential to be developed as a new therapeutic drug. PMID:27006947
Zibaei, Mohammad; Sadjjadi, Seyed Mahmoud; Karamian, Mehdi; Uga, Shoji; Oryan, Ahmad; Jahadi-Hosseini, Seyed Hamidreza
The aim of this study was to compare the performance of three in-house diagnostic tests, that is, histopathology, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR), for the diagnosis after experimental infection with Toxocara cati. Twenty Mongolian gerbils and Wistar rats were divided into ten groups (n = 2/group). Toxocara cati infections were established in Mongolian gerbils and Wistar rats by administering doses of 240 and 2500 embryonated Toxocara cati eggs by gavage, respectively. Tissue sections were stained with Haematoxylin and Eosin and observed under the light microscope. Sera and vitreous fluid collected from separate infected groups were tested against Toxocara cati antigens, for 92 days postinfection. Genomic DNA was extracted from formalin-fixed paraffin-embedded (FFPE) blocks, and aqueous fluids belong to the animals. The histopathology test gave negative results among the groups of animals examined between 5 and 92 days postinfection. The ELISA results showed that anti-Toxocara antibodies have risen between 7 and 61 days postinfection in sera and vitreous fluid in the animals infected, respectively. Analysis of PCR products revealed positive band (660 bp) in the orbital tissue infected Mongolian gerbils at 5 days postinfection. Of the three evaluated methods, the PCR could be recommended for scientific and laboratory diagnoses of toxocariasis in experimentally infected animals.
Bayssade-Dufour, Ch; Vuong, P N; René, M; Martin-Loehr, C; Martins, C
Over the past few years, the cercarial dermatitis has become a new problem of public health, obviously linked to the prolonged stay of migrant birds on our territory. This is a skin affection characterized by pruriginous and papulous eruptions caused by penetration of avian bilharzian larvae under the skin. These larvae are emitted by molluscs, mostly limneids. In aquatic birds, especially in migrating Anatidae, these larvae reach the visceral vessels, become adults in a few weeks, lay eggs, then degenerate. Corresponding miracidia contaminate new limneids. Since 1993, the total number of annual cases of cercarial dermatitis has increased from only ten to thousands in France and the affection rages in pools where limneids, migrating water birds and swimmers gather together. Fever, respiratory and/or digestive allergic symptoms appear in some cases. This clinical pattern has encouraged to undertake research on the future of these bilharzian larvae in mammals organism. A preliminary investigation on a rodent model showed that, once the skin barrier had been crossed, the schistosomulae migrated into the lungs of the host; there they survived a week and induced lesions. The goal of this study is to carry on the research, over a longer period, after exposure to cercariae, simultaneously in mammals and birds, with two species of bilharziae present in France. The selected models are the gerbil Meriones unguiculatus for mammals, and the ducks Anas platyrhynchos and Cairina moschata, for birds. 5 M. unguiculatus and 2 A. platyrhynchos were exposed to cercariae emitted by Radix auricularia; 2 gerbils and 5 A. platyryhnchos to larvae of R. peregra, 3 C. moschata to larvae emitted by two species of molluscs: 70-230 from R. auricularia and 330-585 from R. peregra. 5 gerbils died between 2 and 5 weeks after exposure, 2 gerbils sacrificed early, served as control animals for skin manifestations. Eight ducks were sacrificed between 2 and 4 weeks after; the 2 last ones, exposed
Winkler, D T; Scotti, A L; Nitsch, C
Mongolian gerbils are epilepsy-prone animals. In adult gerbils two major groups can be differentiated according to their seizure behavior: Highly seizure-sensitive gerbils exhibit facial and forelimb clonus or generalized tonic-clonic seizures from the first test on, while kindled-like gerbils are seizure free for the first three to six consecutive tests, later develop forelimb myoclonus, and eventually progress to generalized tonic-clonic seizures. In the hippocampus, seizure history of the individual animal is mirrored in the intensity in which GABAergic neurons are immunostained for the calcium-binding protein parvalbumin: they lose parvalbumin with increasing seizure incidence. In a first step to clarify the influence of hippocampal projection neurons on spontaneous seizure behavior and related parvalbumin expression, we induced degeneration of the CA1 pyramidal cells by transient forebrain ischemia. This results in a decreased seizure sensitivity in highly seizure-sensitive gerbils. The kindling-like process, however, is not permanently blocked by the ischemic nerve cell loss, suggesting that an intact CA1 field is not a prerequisite for the development of seizure behavior. The seizure-induced loss of parvalbumin from the ischemia-resistant interneurons recovers after ischemia. Thus, changes in parvalbumin content brought about by repeated seizures are not permanent but can rather be modulated by novel stimuli.
Lalor, J.H.; Llewellyn, G.C.
The interaction of sodium selenite (Na/sub 2/SeO/sub 3/) and aflatoxin B/sub 1/ (AFB/sub 1/) was studied in 6-wk-old male Mongolian gerbils. Each of four groups of gerbils were fed one of the following diets during a 12-wk experimental period: control (commercial Chow), 5.0 ppm Na/sub 2/SeO/sub 3/, 12.8 ppm AFB/sub 1/, or 5.0 ppm Na/sub 2/SeO/sub 3/ + 12.8 ppm AFB/sub 1/. Animals receiving Na/sub 2/SeO/sub 3/ in the diet, alone and with AFB/sub 1/, had a significantly lower mean total weight gain during the experiment than did control animals. Animals receiving both compounds together displayed a very high level of physical activity compared to the three other groups. Blood analysis showed no change in total leukocytes, but the relative percentage of lymphocytes increased and the percentage of neutrophils decreased concurrently in the order: control < AFB/sub 1/ < Na/sub 2/SeO/sub 3/ + AFB/sub 1/ < Na/sub 2/SeO/sub 3/. A significant reduction in organ weight relative to body weight was observed in the liver, kidney, and lung of the animals fed AFB/sub 1/ alone but only in the liver of those fed both Na/sub 2/SeO/sub 3/ and AFB/sub 1/. No similar alterations were observed in the Na/sub 2/SeO/sub 3/ group. Histopathological examination revealed considerably less hepatic damage in animals fed Na/sub 2/SeO/sub 3/ with AFB/sub 1/ than in those receiving either compound alone. Renal and intestinal damage, however, was most severe in this double-treatment group. Hepatic protein analysis revealed two protein peaks in the Na/sub 2/SeO/sub 3/ + AFB/sub 1/ group that were absent in all other groups. It was concluded that these proteins may be selenoproteins directly or indirectly involved in the lower incidence of histopathological damage in this group.
Himeda, Toshiki; Hayakawa, Natsumi; Tounai, Hiroko; Sakuma, Mio; Kato, Hiroyuki; Araki, Tsutomu
We investigated the immunohistochemical alterations of parvalbumin (PV)-expressing interneurons in the hippocampus after transient cerebral ischemia in gerbils in comparison with neuronal nitric oxide synthase (nNOS)-expressing interneurons. We also examined the effect of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pitavastatin against the damage of neurons and interneurons in the hippocampus after cerebral ischemia. Severe neuronal damage was observed in the hippocampal CA1 pyramidal neurons 5 and 14 days after ischemia. The PV immunoreactivity was unchanged up to 2 days after ischemia. At 5 and 14 days after ischemia, in contrast, a conspicuous reduction of PV immunoreactivity was observed in interneurons of the hippocampal CA1 sector. Furthermore, a significant decrease of PV immunoreactivity was found in interneurons of the hippocampal CA3 sector. No damage of nNOS-immunopositive interneurons was detected in the gerbil hippocampus up to 1 day after ischemia. Thereafter, a decrease of nNOS immunoreactive interneurons was found in the hippocampal CA1 sector up to 14 days after ischemia. Pitavastatin significantly prevented the neuronal cell loss in the hippocampal CA1 sector 5 days after ischemia. Our immunohistochemical study also showed that pitavastatin prevented significant decrease of PV- and nNOS-positive interneurons in the hippocampus after ischemia. Double-labeled immunostainings showed that PV immunoreactivity was not found in nNOS-immunopositive interneurons of the brain. The present study demonstrates that cerebral ischemia can cause a loss of both PV- and nNOS-immunoreactive interneurons in the hippocampal CA1 sector. Our findings also show that the damage to nNOS-immunopositive interneurons may precede the neuronal cell loss in the hippocampal CA1 sector after ischemia and nNOS-positive interneurons may play some role in the pathogenesis of cerebral ischemic diseases. Furthermore, our present study indicates that pitavastatin can
Khazaee, Manoochehr; Hamidian, Amir Hossein; Alizadeh Shabani, Afshin; Ashrafi, Sohrab; Mirjalili, Seyyed Ali Ashghar; Esmaeilzadeh, Esmat
Rodents frequently serve as bioindicator to monitor the quality of the environment. Concentrations of 11 elements (Cd, Co, Ti, Fe, Mn, Cu, Sb, As, Sr, Ni, and Cr) were investigated and compared in liver, hair, femur, and lung of the Persian jird (Meriones persicus) from Darreh Zereshk copper mine, Iran. Metals were determined in different tissues of 39 individuals of Persian jird, collected by snap trap in 2014 from five areas of Darreh Zereshk copper mine. Samples were prepared by wet digestion method, and the contents of elements were analyzed with ICP-OES (VARIAN, 725-ES) instrument. Cadmium, Sb, and Co were below the limit of detection, and Mn and As were found only in hair and liver tissues. We detected the highest concentration of Cu, As, Ti, Fe, Mn, Cr, and Ni in hair in comparison with other tissues. Significant higher levels of Ti in femur and hair; Fe in liver and hair; Mn in liver; As in hair; Sr in lung; Cr in lung, hair, femur, and liver; Cu in femur; and Ni in liver and lung tissues were observed in females. Nearly all element concentrations in the tissues of Persian jird from flotation site, Darreh Zereshk and Hasan Abad villages and leaching site (mining areas) were higher than those from tailing dump site (reference site). We found the highest concentrations of As in liver and hair; Ni and Cr in liver, hair, and lung; and Sr in lung and hair tissues of Persian jird in leaching site. We tried to specify the status of elements before fully exploitation of Darreh Zereshk copper mine by using bioindicator species. Based on our achievements, initial activities did not strongly pollute the surrounded environment of the mine. The high abundance of Persian jird as well as their several proper features makes them a suitable species for biomonitoring programs especially for further studies will be performed after full exploitation of Darreh Zereshk copper mine.
Rennie, K. J.; Ricci, A. J.; Correia, M. J.
1. Membrane potential responses of dissociated gerbil type I semicircular canal hair cells to current injections in whole cell current-clamp have been measured. The input resistance of type I cells was 21.4 +/- 14.3 (SD) M omega, (n = 25). Around the zero-current potential (Vz = -66.6 +/- 9.3 mV, n = 25), pulsed current injections (from approximately -200 to 750 pA) produced only small-amplitude, pulse-like changes in membrane potential. 2. Injecting constant current to hyperpolarize the membrane to around -100 mV resulted in a approximately 10-fold increase in membrane resistance. Current pulses superimposed on this constant hyperpolarization produced larger and more complex membrane potential changes. Depolarizing currents > or = 200 pA caused a rapid transient peak voltage before a plateau. 3. Membrane voltage was able to faithfully follow sine-wave current injections around Vz over the range 1-1,000 Hz with < 25% attenuation at 1 kHz. A previously described K conductance, IKI, which is active at Vz, produces the low input resistance and frequency response. This was confirmed by pharmacologically blocking IKI. This conductance, present in type I cells but not type II hair cells, would appear to confer on type I cells a lower gain, but a much broader bandwidth at Vz, than seen in type II cells.
Araki, T; Kato, H; Liu, X H; Kogure, K; Kato, K; Itoyama, Y
We investigated postischemic changes of non-pyramidal neurons in the gerbil hippocampus 1 h - 7 days after 10 min of cerebral ischemia, with parvalbumin and microtubule-associated protein 2 (MAP2)-immunohistochemistry. Parvalbumin-immunoreactive interneurons in the hippocampus were unaffected up to 24 h after ischemia. A slight reduction of the immunoreactivity in neuronal processes was seen in the hippocampal CA1 sector 48 h after ischemia. Seven days after ischemia, a marked loss of parvalbumin-immunoreactive interneurons was observed in the hippocampal CA1 and CA3 sectors. Furthermore, reduced staining in the dentate granular and molecular layers was observed. MAP2-immunoreactive pyramidal neurons in the hippocampus were unchanged up to 48 h after ischemia. Seven days after ischemia, a severe loss of MAP2 immunoreactivity was found in the hippocampal CA1 and CA3 neurons and dentate hilar neurons. However, scattered CA1 neurons, most likely interneurons, preserved MAP2 immunoreactivity. The results demonstrate that transient cerebral ischemia can cause a loss of parvalbumin-immunoreactive interneurons in the hippocampus. Furthermore, some interneurons seem to lose parvalbumin synthesis. Although dentate granule cells are resistant to ischemia, considerable reductions of afferent input was suggested by parvalbumin staining.
Mori, S; Tanaka, R; Minakawa, T; Onda, K
Confluent monolayers of capillary endothelial cells derived from Mongolian gerbil brain were irradiated with a single exposure of x-rays, and their radiosensitivity and sequential changes in morphology, staining intensity for factor VIII-related antigen (F VIII RAg), and capacity to produce prostacyclin (PGI2) were examined. The radiobiologic parameters that characterized the dose-response survival curve for these cells were found to be n = 1.9, Dq = 140 rad, and D0 = 190 rad. Morphologically, nuclear and cytoplasmic swelling, vacuolation of cytoplasm, and giant cell formation occurred in a dose dependent manner after 24 hours from irradiation. Decreased staining intensity for F VIII RAg was observed in morphologically affected cells. The capacity to synthesize PGI2 was significantly enhanced at 24 hours, but less significant at 72 hours after irradiation. The present data suggest that the radiosensitivity of brain capillary endothelial cells may be somewhat lower than that of endothelial cells originated from larger vessels, and that radiation induced morphological and functional changes in the brain capillary endothelial cells may be quantitatively similar to the changes in endothelial cells of larger vessels.
Araki, T; Kogure, K
We investigated the effect of vinconate, a novel vinca alkaloid derivative, on delayed neuronal death using Mongolian gerbils. The animals were allowed to survive for 7 d after 3 or 5 min of forebrain ischemia induced by bilateral occlusion of the common carotid arteries. Morphological changes and calcium (45Ca) accumulation were evaluated in the CA1 sector of the hippocampus after ischemia. Vinconate (50, 100, and 300 mg/kg) showed protective effects against neuronal death in a dose-dependent manner when administered intraperitoneally (ip) 10 min before 5 min of ischemia. However, the administration of vinconate (100 and 300 mg/kg, ip) immediately after 5 min of ischemia showed no therapeutic effect, whereas a marked therapeutic effect of vinconate (50 and 100 mg/kg, ip) was observed when administered immediately after 3 min of ischemia. An anesthetic dose of pentobarbital (40 mg/kg, ip) also produced significant protection against neuronal death. Furthermore, a 45Ca autoradiographic study indicated that a marked calcium accumulation was found in the Ca1 sector at 7 d after 5 min of ischemia, which was consistent with the extent of histological neuronal damage. When vinconate (100 and 300 mg/kg, ip) was administered 10 min before 5 min of ischemia, the abnormal calcium accumulation was not detected in the CA1 sector. These data indicate that suppression of abnormal neuronal activity may be owing to the antagonistic action of vinconate on calcium accumulation.
Sannes, P. L.; Hayes, T. G.
A number of studies concerning the effects of hypergravity on bone have shown increases in bone mass or bone dimensions. Correlative studies, which could provide clues to the mechanism for such a response, have been lacking. The purpose of the present study was to evaluate the ultrastructure of parathyroid glands of Mongolian gerbils exposed to a continuous 2 X gravity force for 60 d. It was found that the experimental animals had parathyroid glands which had a greater percentage of chief cells in the active stage of their secretory cycle when compared with control animals. This result was interpreted to indicate an increase in parathyroid gland secretory activity and, hence, an increase in parathyroid hormone release. It was suggested that increased parathyroid secretory activity was necessary to maintain serum calcium levels of hypergravity animals within normal limits. Cellular forms resembling water clear cells and highly compact, degenerating cells were described in experimental animals but not in controls. Areas suggestive of cellular dissolution and disorganization were also reported in experimental parathyroids.
Park, Joon Ha; Shin, Bich Na; Chen, Bai Hui; Kim, In Hye; Ahn, Ji Hyeon; Cho, Jeong-Hwi; Tae, Hyun-Jin; Lee, Jae-Chul; Lee, Choong-Hyun; Kim, Young-Myeong; Lee, Yun Lyul; Kim, Sung Koo; Won, Moo-Ho
Atomoxetine (ATX) is a non-stimulant selective norepinephrine reuptake inhibitor that is widely used for the treatment of attention-deficit/hyperactivity disorder (ADHD). In this study, we firstly examined neuroprotective effects of pre- or post-treatment with 15 and 30 mg/kg ATX against ischemic damage in the gerbil hippocampal cornus ammonis 1 (CA1) region subjected to 5 min of transient cerebral ischemia using cresyl violet staining, neuronal nuclei immunohistochemistry and Fluoro-J B histofluorescence staining. We found that only pre-treatment with 30 mg/kg ATX protected CA1 pyramidal neurons from ischemic insult. In addition, pre-treatment with 30 mg/kg ATX, which had neuroprotective effect against ischemic damage, distinctly attenuated the activation of astrocytes and microglia in the ischemic CA1 region compared with the vehicle-treated ischemia group by glial fibrillary acidic protein (for astrocytes) and ionized calcium-binding adapter molecule 1 (for microglia) immunohistochemistry. In brief, our present results indicate that ATX has neuroprotective effect against transient cerebral ischemic insult and that the neuroprotective effect of ATX may be closely associated with attenuated glial activation.
Schnupp, Jan W. H.; Garcia-Lazaro, Jose A.; Lesica, Nicholas A.
Periodicities in sound waveforms are widespread, and shape important perceptual attributes of sound including rhythm and pitch. Previous studies have indicated that, in the inferior colliculus (IC), a key processing stage in the auditory midbrain, neurons tuned to different periodicities might be arranged along a periodotopic axis which runs approximately orthogonal to the tonotopic axis. Here we map out the topography of frequency and periodicity tuning in the IC of gerbils in unprecedented detail, using pure tones and different periodic sounds, including click trains, sinusoidally amplitude modulated (SAM) noise and iterated rippled noise. We found that while the tonotopic map exhibited a clear and highly reproducible gradient across all animals, periodotopic maps varied greatly across different types of periodic sound and from animal to animal. Furthermore, periodotopic gradients typically explained only about 10% of the variance in modulation tuning between recording sites. However, there was a strong local clustering of periodicity tuning at a spatial scale of ca. 0.5 mm, which also differed from animal to animal. PMID:26379508
Onodera, H.; Sato, G.; Kogure, K.
Quantitative receptor autoradiography was used to measure the binding of gamma-aminobutyric acid (GABA) and benzodiazepine receptors after ischemia by means of transient occlusion of bilateral common carotid arteries in the gerbil. (/sup 3/H)Muscimol was used to label the GABAA receptors and (/sup 3/H)flunitrazepam to label central type benzodiazepine receptors. In the superolateral convexities of the frontal cortices, (/sup 3/H)muscimol binding was increased in 60% of the animals killed 3 days after ischemia, and decreased in 67% of the animals killed 27 days after ischemia. Twenty-seven days after ischemia, (/sup 3/H)flunitrazepam binding in the substantia nigra pars reticulata increased to 252% of the control, though the increase in (/sup 3/H)muscimol binding was not significant. In the dorsolateral region of the caudate putamen, marked neuronal necrosis and depletion of both (/sup 3/H)muscimol and (/sup 3/H)flunitrazepam binding sites were observed 27 days after ischemia, the ventromedial region being left intact. In spite of the depletion of pyramidal cells in the CA1 region of the hippocampus, both (/sup 3/H)muscimol and (/sup 3/H)flunitrazepam binding sites were preserved 27 days after ischemia. Since our previous study revealed that adenosine A1 binding sites were depleted in the CA1 subfield of the hippocampus after ischemia correlating with neuronal damage, GABAA and benzodiazepine receptors may not be distributed predominantly on the pyramidal cells in the CA1 region.
Okada, Masahiro; Kawaguchi, Akira T; Hakuba, Nobuhiro; Takeda, Shoichiro; Hyodo, Jun; Imai, Kiyohiro; Hato, Naohito; Gyo, Kiyofumi
To test liposome-encapsulated hemoglobin (LEH) in transient cochlear ischemia/reperfusion as a model of sudden deafness, Mongolian gerbils were randomly assigned to receive 2 mL/kg of either low-affinity LEH (l-LEH, P₅₀0₂ = 40 mm Hg), high-affinity LEH (h-LEH, P₅₀0₂ = 10 mm Hg), homologous red blood cells (RBCs), or saline (each group n = 6) 30 min before 15-min occlusion of the bilateral vertebral arteries and reperfusion. Sequential changes in hearing were assessed by auditory brain response 1, 4, and 7 days after ischemia/reperfusion, when the animals were sacrificed for pathological studies. h-LEH was significantly more protective than l-LEH in suppressing hearing loss, in contrast to RBC or saline treatment, at 8, 16, and 32 kHz, where hearing loss was most severe (P < 0.05 between any two groups) on the first day after cochlear ischemia/reperfusion. Thereafter, hearing loss improved gradually in all groups, with a significant difference among groups up to 7 days, when morphological studies revealed that the inner hair cells but not the outer hair cells, were significantly lost in the groups in the same order. The results suggest that pretreatment with h-LEH is significantly more protective than l-LEH in mitigating hearing loss and underlying pathological damage, in contrast to transfusion or saline infusion 7 days after transient cochlear ischemia/reperfusion.
Mirjalali, H; Kia, E B; Kamranrashani, B; Hajjaran, H; Sharifdini, M
Rodentolepis nana (syn. Hymenolepis nana) is a cyclophyllidean zoonotic enteric parasite with worldwide distribution. In humans, it is more prevalent in children, especially in temperate zones. A morphologically similar species of R. nana occurs in different rodents, including gerbils. In the present study molecular characterization of five isolates of R. nana from Rhombomys opimus in the Golestan Province (n= 2) and Razavi Khorasan Province (n= 3), both in north-eastern Iran, were analysed. After DNA extraction, the internal transcribed spacer 2 (ITS2) region of the R. nana isolates was amplified and sequenced, and genetic variation was analysed. Accordingly, two isolates from the Razavi Khorasan Province showed ITS2 signatures that differed from the isolates from the Golestan Province. The third isolate from Razavi Khorasan did not reveal these specific signatures, but exhibited sparse nucleotide polymorphisms in the ITS2 sequence. The ITS gene is conserved, and variation in this fragment could be an interesting subject for further inspection of existing variation in the genome of R. nana, among different domestic and wildlife host species and from different areas.
Donzelli, Andrea; Braida, Daniela; Finardi, Annamaria; Capurro, Valeria; Valsecchi, Anna Elisa; Colleoni, Mariapia; Sala, Mariaelvina
Genistein is a naturally occurring plant-derived phytoestrogen, present in the human diet, known to possess some beneficial effects. The present study investigated the effect of genistein on neuroprotection evaluated through electroencephalographic and behavioural correlates in a model of global cerebral ischemia in gerbils. Over the dose range tested, genistein (3 and 10 mg/kg), given 5 min after recirculation antagonized the ischemia-induced electroencephalographic total spectral power decrease 7 days after ischemia; fully prevented ischemia-induced hyperlocomotion evaluated 1 day after ischemia; reversed ischemia-induced memory impairment evaluated through both nest building behaviour and object recognition test; decreased malondialdehyde overproduction in the brain, evaluated 7 days after reperfusion; and fully promoted the survival of pyramidal cells in the CA(1) hippocampal subfield. The selective antagonist for estrogen receptor-β (ERβ), 4-[2-phenyl-5,7-bis(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-3-yl]phenol (PHTPP) given 30 min before carotid occlusion, fully prevented the neuroprotective effect of genistein at the dose of 3 mg/kg. These results demonstrate the neuroprotective effect of genistein through the activation of ERβ and provide further grounds for the growing interest concerning the true potential of phytoestrogens as compounds to beneficially affect brain injury without having the disadvantages of estrogens.
Experimentally transient global cerebral ischemia using animal models have been thoroughly studied and numerous reports suggest the involvement of oxidative stress in the pathogenesis of neuronal death in ischemic lesions. In animal models, during the reperfusion period after ischemia, increased oxygen supply results in the overproduction of reactive oxygen species (ROS), which are involved in the process of cell death. ROS, such as superoxide anions, hydroxyl free radicals, hydrogen peroxide and nitric oxide are produced as a consequence of metabolic reactions and central nervous system activity. These reactive species are directly involved in the oxidative damage of cellular macromolecules such as nucleic acids, lipids and proteins in ischemic tissues, which can lead to cell death. Antioxidant enzymes are believed to be among the major mechanisms by which cells counteract the deleterious effect of ROS after cerebral ischemia. Consequently, antioxidant strategies have been long suggested as a therapy for experimental ischemic stroke; however, clinical trials have not yet been able to promote the translation of this concept into patient treatment regimens. This article focuses on the contribution of oxidative stress or antioxidants to the post-ischemic neuronal death following transient global cerebral ischemia by using a gerbil model. PMID:25276473
Li, B; Azhati, Rehemu; Meng, W W; Luo, T; Li, B; Abulimiti, Maituohuti; Wang, X H; Dai, X; Zhang, Y J
Objective: To understand the histopathological and ultrastructural pathology changes of great gerbils in the Junggar Basin to Yersinia pestis infection. Methods: Forty captured great gerbils from the Junggar Basin that tested negative for anti-F1 antibodies were infected. The Y. pestis strain 2504, isolated from a live great gerbil in the natural plague foci of the Junggar Basin in 2005 with a median lethal dose (LD(50)) of <10 CFU/ml, was used in this study. Forty great gerbils were divided into seven infection groups and were subcutaneously infected with 7.4×10(5), 7.4×10(6), 7.4×10(7), 7.4×10(8), 7.4×10(9), 7.4×10(10), or 3.0×10(11) CFU/ml of 2504. One milliliter of physiological saline was injected in the noninfected group as a control. We collected the liver, spleen, heart, and lung from all animals for histopathologic and ultrastructural pathology examination. Results: Great gerbils in the 7.4×10(8)-3.0×10(11) CFU/ml groups did not survive and exhibited pathological changes and altered ultrastructural pathology. The liver tissue of infected great gerbils showed spotty necrosis and fatty degeneration, intranuclear canaliculi with increased hepatocytes, and uneven distribution of organelles. Additionally, reactive proliferation of lymphoid tissue in the spleen, blood sinusoid lacunae with neutrophil infiltration, and phagocytosed bacteria in phagocyte cells were observed. Myocardial fiber hypertrophy and interstitial indistinction, nuclear matrices decreased in cardiac myocytes, and loose arrangement of myogenic fibers in myocardial cells were also observed. Angiectasia, capillary congestion, and tissue necrosis were found in the lung. No significant difference in histopathological and ultrastructural pathology in the parenchymal organ was observed between the 7.4×10(5)-7.4×10(7) CFU/ml groups and the 7.4×10(8)-3.0×10(11) CFU/ml groups, and no specific death caused by Y. pestis infection was apparent in the 7.4×10(5)-7.4×10(7) CFU/ml groups
Peitz, B; Foreman, D; Schmitt, M
The testes of the spiny mice showed asymmetry, the left being significantly heavier than the right (P = 0.025). Histological studies indicated that spermatozoa were first present in the testes of animals 35--45 days of age but the maturation of the accessory glands, especially the lateral prostates and coagulating glands, occurred later. The highest fructose concentration in the adult was in the lateral prostates (126.97 +/- 22.23 mg fructose/100 g, n = 5) and coagulating glands (99.38 +/- 17.65 mg fructose/100 g gland weight, n = 5). Coagulation tests of mixtures of extracts of seminal vesicles and coagulating glands from spiny mice and rats indicated that the vesiculase of the spiny mouse was active on rat substrates and vice versa. Cross-reactions of extracts of house mouse (Mus musculus), hamster (Mesocricetus auratus), gerbil (Meriones unguiculatus), and guinea-pig (Cavia porcellus) seminal vesicles (substrate) and coagulating glands (vesiculase) with those of rats and spiny mice showed that although the substrates of rat and spiny mouse were readily coagulated by vesiculase from all the other species, rat and spiny mouse vesiculase were not equally active on substrates of the other species.
Kváč, Martin; Hofmannová, Lada; Hlásková, Lenka; Květoňová, Dana; Vítovec, Jiří; McEvoy, John; Sak, Bohumil
The morphological, biological, and molecular characteristics of Cryptosporidium hedgehog genotype are described, and the species name Cryptosporidium erinacei n. sp. is proposed to reflect its specificity for hedgehogs under natural and experimental conditions. Oocysts of C. erinacei are morphologically indistinguishable from Cryptosporidium parvum, measuring 4.5-5.8 μm (mean=4.9 μm) × 4.0-4.8 μm (mean=4.4 μm) with a length to width ratio of 1.13 (1.02-1.35) (n=100). Oocysts of C. erinacei obtained from a naturally infected European hedgehog (Erinaceus europaeus) were infectious for naïve 8-week-old four-toed hedgehogs (Atelerix albiventris); the prepatent period was 4-5 days post infection (DPI) and the patent period was longer than 20 days. C. erinacei was not infectious for 8-week-old SCID and BALB/c mice (Mus musculus), Mongolian gerbils (Meriones unguiculatus), or golden hamsters (Mesocricetus auratus). Phylogenetic analyses based on small subunit rRNA, 60 kDa glycoprotein, actin, Cryptosporidium oocyst wall protein, thrombospondin-related adhesive protein of Cryptosporidium-1, and heat shock protein 70 gene sequences revealed that C. erinacei is genetically distinct from previously described Cryptosporidium species.
Zosuls, Aleks; Rupprecht, Laura C.; Mountain, David C.
Here we present the results from a new high-frequency mechanical stimulation system that was designed to provide more precise local excitation and motion sensing of the organ of Corti (OC/BM complex). It is based on mechanical tissue excitation via a small vibrating probe and measurement using stroboscopic video microscopy. The system is currently capable of measuring sub-micrometer motion at frequencies from DC to 60 kHz. Measurements were performed on excised Mongolian gerbil (Meriones unguiculatus) cochleae. The underside of the BM was mechanically stimulated in the direction normal to the membrane with a 20 μm diameter glass probe. Data was collected at multiple focal planes from the BM to the tectorial membrane in order to capture motion for cellular and extracellular structures. For this study, inner hair cell hair bundles and basilar membrane collagen fiber bundle regions of interest were selected and displacements quantified using a cross-correlation technique. Displacement magnitude and phase was measured as a function of distance from the probe and a function of stimulus frequency. At certain frequencies both magnitudes and phases decreased with distance from the probe in a manner that suggests that both direct longitudinal coupling and wave propagation were contributing to the responses.
Wagner, I; Capesius, I
The relative amounts of the five nucleosides (deoxycytidine, 5-methyldeoxycytidine, deoxyadenosine, deoxyguanosine and thymidine) in the DNA of nine plant species, one plant satellite DNA, and one animal species were determined by high performance liquid chromatography. The method allows the clean separation of the nucleosides from 10 microgram samples with 15 min. The following values for the proportion of methylated cytosines among all cytosines were obtained: Lobularia maritima 18.5%, Nicotiana tabacum 32.6%, Pisum sativum 23.2%, Rhinanthus minor 29.2%, Sinapsis alba 12.2%, Vicia faba 30.5%, Viscum album 23.2%, Cymbidium pumilum 18.8%, Cymbidium pumilum AT-rich satellite DNA 15.8%, Triticum aestivum 22.4%. DNA of an animal, the gerbil, Meriones unguiculatus, had a methylation percentage of 3.1%. An estimate of the GC content based on the buoyant density of DNA tends to be lower than the actual value, an estimate based on the melting temperature tends to be higher. This supports the finding by other authors that DNA methylation decreases the buoyant density and may increase the melting temperature at high m5C concentration.
The generation of distortion product otoacoustic emissions (DPOAEs) has been summarized using a two-mechanism theory consisting of nonlinear distortion and linear coherent reflection. However, the precise generation site in the cochlea is still unclear. The current study in gerbils used a third tone in different cochlear regions to probe the cochlear origin site of DPOAEs. DPOAEs and their intracochlear sources, distortion products (DPs), were simultaneously measured. Our results suggest that the major generation site of DPOAEs evoked by an f2/f1 ratio of 1.25 extends basal to the primary f2 place, which is consistent with notions about the location of the cochlear amplifier.
Lelas, Snjezana; Li, Yu-Wen; Wallace-Boone, Tanya L; Taber, Matthew T; Newton, Amy E; Pieschl, Rick L; Davis, Carl D; Molski, Thaddeus F; Newberry, Kimberly S; Parker, Michael F; Gillman, Kevin W; Bronson, Joanne J; Macor, John E; Lodge, Nicholas J
The known interactions between the serotonergic and neurokinin systems suggest that serotonin reuptake inhibitor (SSRIs) efficacy may be improved by neurokinin-1 receptor (NK1R) antagonism. In the current studies combination of a subeffective dose of an SSRI (0.3 mg/kg fluoxetine or 0.03 mg/kg citalopram) with a subeffective dose of an NK1R antagonist (0.3 mg/kg aprepitant or 1 mg/kg CP-122,721) produced efficacy in the gerbil forced swim test (FST). Serotonin transporter (SERT) occupancy produced by 1 mg/kg fluoxetine (lowest efficacious dose) was 52 ± 5% and was reduced to 29 ± 4% at 0.3 mg/kg, a dose that was efficacious in combination with 0.3 mg/kg aprepitant or 1 mg/kg CP-122,721; the corresponding NK1R occupancies were 79 ± 4% and 61 ± 4% for aprepitant and CP-122,721, respectively. For citalopram, SERT occupancy at the lowest efficacious dose (0.1 mg/kg) was 50 ± 4% and was reduced to 20 ± 5% at 0.03 mg/kg, a dose that was efficacious when combined with aprepitant (0.3 mg/kg). Aprepitant (10 mg/kg) augmented the serotonin elevation produced by fluoxetine (1 or 10 mg/kg) in the gerbil prefrontal cortex; i.e. NK1R antagonism can modulate serotonin responses. A novel orally-available dual-acting NK1R antagonist/SERT inhibitor BMS-795176 is described; gerbil Ki = 1.4 and 1 nM at NK1R and SERT, respectively. BMS-795176 was efficacious in the gerbil FST; efficacy was observed with 35 ± 3% SERT occupancy and 73 ± 3% NK1R occupancy. The interaction between NK1R antagonism and SERT inhibition to lower the SERT occupancy required for antidepressant-like efficacy suggests that BMS-795176 has the potential to improve efficacy with a reduction in SSRI-associated side effects.
Jarvers, Christian; Brosch, Tobias; Brechmann, André; Woldeit, Marie L.; Schulz, Andreas L.; Ohl, Frank W.; Lommerzheim, Marcel; Neumann, Heiko
Biologically plausible modeling of behavioral reinforcement learning tasks has seen great improvements over the past decades. Less work has been dedicated to tasks involving contingency reversals, i.e., tasks in which the original behavioral goal is reversed one or multiple times. The ability to adjust to such reversals is a key element of behavioral flexibility. Here, we investigate the neural mechanisms underlying contingency-reversal tasks. We first conduct experiments with humans and gerbils to demonstrate memory effects, including multiple reversals in which subjects (humans and animals) show a faster learning rate when a previously learned contingency re-appears. Motivated by recurrent mechanisms of learning and memory for object categories, we propose a network architecture which involves reinforcement learning to steer an orienting system that monitors the success in reward acquisition. We suggest that a model sensory system provides feature representations which are further processed by category-related subnetworks which constitute a neural analog of expert networks. Categories are selected dynamically in a competitive field and predict the expected reward. Learning occurs in sequentialized phases to selectively focus the weight adaptation to synapses in the hierarchical network and modulate their weight changes by a global modulator signal. The orienting subsystem itself learns to bias the competition in the presence of continuous monotonic reward accumulation. In case of sudden changes in the discrepancy of predicted and acquired reward the activated motor category can be switched. We suggest that this subsystem is composed of a hierarchically organized network of dis-inhibitory mechanisms, dubbed a dynamic control network (DCN), which resembles components of the basal ganglia. The DCN selectively activates an expert network, corresponding to the current behavioral strategy. The trace of the accumulated reward is monitored such that large sudden
Seidl, Armin H; Grothe, Benedikt
Sound localization is one of the most important tasks performed by the auditory system. Differences in the arrival time of sound at the two ears are the main cue to localize low-frequency sound in the azimuth. In the mammalian brain, such interaural time differences (ITDs) are encoded in the auditory brain stem; first by the medial superior olive (MSO) and then transferred to higher centers, such as the dorsal nucleus of the lateral lemniscus (DNLL), a brain stem nucleus that gets a direct input from the MSO. Here we demonstrate for the first time that ITD sensitivity in gerbils undergoes a developmental maturation after hearing onset. We further show that this development can be disrupted by altering the animal's acoustic experience during a critical period. In animals that had been exposed to omnidirectional white noise during a restricted time period right after hearing onset, ITD tuning did not develop normally. Instead, it was similar to that of juvenile animals 3 days after hearing onset, with the ITD functions not adjusted to the physiological range. Animals that had been exposed to omnidirectional noise as adults did not show equivalent abnormal ITD tuning. The development presented here is in contrast to that of the development of neuronal representation of ITDs in the midbrain of barn owls and interaural intensity differences in ferrets, where the representations are adjusted by an interaction of auditory and visual inputs. The development of ITD tuning presented here most likely depends on normal acoustic experience and may be related to the maturation of inhibitory inputs to the ITD detector itself.
Rhee, Chung-Ku; Kwon, Pil Seung; Ahn, Jin Chul; Chung, Phil Sang; Ge, Ruifeng
The aim of this study was to evaluate antibacterial effects of PDT on common bacteria causing otitis media with effusion (OME). In vitro study was carried out using a hematoporphyrin derivative sensitizer (photogem) and 632 nm diode laser on H. influenzae, M. catarrhalis, and S. pneumoniae. One ml of each bacterial suspension was incubated for 3 hours and various concentrations of photogem were administered into the suspension. The suspensions were irradiated with 632 diode laser (15 J/cm2). The presence of colony forming units of the bacteria was examined, microscopic structures of bacteria were examined by TEM, and cytometry of bacteria was performed. The PDT was effective in killing all 3 kinds of bacteria. TEM showed damaged bacterial cell membrane and cytoplasmic structures and the flow cytometry showed lower number of viable bacteria in PDT group comparing to the control group. In vivo PDT study was performed using gerbil. S. pneumoniae or H. influenzae was injected into bullae. Photogem was injected into bullae in 2 days by when OME was developed and transcanal irradiation of 632 nm diode laser (90 J) was performed with a fiber perforated through an ear drum into a middle ear cavity and bulla. Four days after PDT, middle ear and bulla were washed with DPBS and the washed DPBS was cultured. The presence of bacterial colonies was examined. PDT was effective in killing S. pneumoniae in 87 % of the infected bullae with OME while it was effective to eradicate H. influenzae in 50 % of the infected bullae with OME. The results of these studies demonstrated that PDT may be effective to treat otitis media. It may have clinical implication to treat otitis media that is resistant to antibiotic therapy.
Fochi, Ricardo A; Santos, Fernanda C A; Goes, Rejane M; Taboga, Sebastião R
Testosterone (T) and oestrogen are the main active steroid hormones in the male and female reproductive system respectively. In female rodents progesterone (P4), together with testosterone and oestrogen, has an essential role in the regulation of the oestrous cycle, which influences the prostate physiology through their oscillations. In this work we investigated how the male and female prostate gland of Mongolian gerbils responds to surgical castration at the start of puberty and what are the effects of T, oestradiol (E2) and P4 replacement, using both quantitative and qualitative methods. We also examined the location of the main steroid receptors present in the prostate. In the castrated animals of both sexes an intense glandular regression, along with disorganization of the stromal compartment, and abundant hyperplasia was observed. The replacement of P4 secured a mild recovery of the glandular morphology, inducing the growth of secretory cells and restoring the androgen receptor (AR) cells. The administration of P4 and E2 eliminated epithelial hyperplasia and intensified gland hypertrophy, favouring the emergence of prostatic intraepithelial neoplasia (PIN). In animals treated with T and P4, even though there are some inflammatory foci and other lesions, the prostate gland revealed morphology closer to that of control animals. In summary, through the administration of P4, we could demonstrate that this hormone has anabolic characteristics, promoting hyperplasia and hypertrophy, mainly in the epithelial compartment. When combined with E2 and T, there is an accentuation of glandular hypertrophy that interrupts the development of hyperplasia and ensures the presence of a less dysplastic glandular morphology.
Fochi, Ricardo A; Santos, Fernanda C A; Goes, Rejane M; Taboga, Sebastião R
Testosterone (T) and oestrogen are the main active steroid hormones in the male and female reproductive system respectively. In female rodents progesterone (P4), together with testosterone and oestrogen, has an essential role in the regulation of the oestrous cycle, which influences the prostate physiology through their oscillations. In this work we investigated how the male and female prostate gland of Mongolian gerbils responds to surgical castration at the start of puberty and what are the effects of T, oestradiol (E2) and P4 replacement, using both quantitative and qualitative methods. We also examined the location of the main steroid receptors present in the prostate. In the castrated animals of both sexes an intense glandular regression, along with disorganization of the stromal compartment, and abundant hyperplasia was observed. The replacement of P4 secured a mild recovery of the glandular morphology, inducing the growth of secretory cells and restoring the androgen receptor (AR) cells. The administration of P4 and E2 eliminated epithelial hyperplasia and intensified gland hypertrophy, favouring the emergence of prostatic intraepithelial neoplasia (PIN). In animals treated with T and P4, even though there are some inflammatory foci and other lesions, the prostate gland revealed morphology closer to that of control animals. In summary, through the administration of P4, we could demonstrate that this hormone has anabolic characteristics, promoting hyperplasia and hypertrophy, mainly in the epithelial compartment. When combined with E2 and T, there is an accentuation of glandular hypertrophy that interrupts the development of hyperplasia and ensures the presence of a less dysplastic glandular morphology. PMID:24205795
Sound energy propagates in the cochlea through a forward-traveling or slow wave supported by the cochlear partition and fluid inertia. Additionally, cochlear models support traveling wave propagation in the reverse direction as the expected mechanism for conveying otoacoustic emissions out of the cochlea. Recently, however, this hypothesis has been questioned, casting doubt on the process by which otoacoustic emissions travel back out through the cochlea. The proposed alternative reverse travel path for emissions is directly through the fluids of the cochlea as a compression pressure in the form of a fast wave. In the present study, a custom-made micro-pressure sensor was used in vivo in the gerbil cochlea to map two-tone-evoked pressure responses at distinct longitudinal and vertical locations in both the scala tympani and scala vestibuli. Analyses of the magnitude and phase of intracochlear pressure responses at the primary tone and distortion product frequencies were used to distinguish between fast and slow waves in both the forward- and reverse-propagation directions. Results demonstrated that distortion products may travel in both forward and reverse directions post-generation and the existence of both traveling and compression waves. The forward-traveling component appeared to duplicate the process of any external tone, tuned to the local characteristic-frequency place, as it increased compressively and nonlinearly with primary-tone levels. A compression wave was evidenced at frequencies above the cutoff of the recording site. In the opposite direction, a reverse-traveling wave played the major role in driving the stapes reversely and contributed to the distortion product otoacoustic emission. The compression wave may also play a role in reverse propagation when distortion products are generated at a region close to the stapes.
Yoo, Dae Young; Lee, Kwon Young; Park, Joon Ha; Jung, Hyo Young; Kim, Jong Whi; Yoon, Yeo Sung; Won, Moo-Ho; Choi, Jung Hoon; Hwang, In Koo
Recent evidence exists that glucose transporter 3 (GLUT3) plays an important role in the energy metabolism in the brain. Most previous studies have been conducted using focal or hypoxic ischemia models and have focused on changes in GLUT3 expression based on protein and mRNA levels rather than tissue levels. In the present study, we observed change in GLUT3 immunoreactivity in the adult gerbil hippocampus at various time points after 5 minutes of transient forebrain ischemia. In the sham-operated group, GLUT3 immunoreactivity in the hippocampal CA1 region was weak, in the pyramidal cells of the CA1 region increased in a time-dependent fashion 24 hours after ischemia, and in the hippocampal CA1 region decreased significantly between 2 and 5 days after ischemia, with high level of GLUT3 immunoreactivity observed in the CA1 region 10 days after ischemia. In a double immunofluorescence study using GLUT3 and glial-fibrillary acidic protein (GFAP), we observed strong GLUT3 immunoreactivity in the astrocytes. GLUT3 immunoreactivity increased after ischemia and peaked 7 days in the dentate gyrus after ischemia/reperfusion. In a double immunofluorescence study using GLUT3 and doublecortin (DCX), we observed low level of GLUT3 immunoreactivity in the differentiated neuroblasts of the subgranular zone of the dentate gyrus after ischemia. GLUT3 immunoreactivity in the sham-operated group was mainly detected in the subgranular zone of the dentate gyrus. These results suggest that the increase in GLUT3 immunoreactivity may be a compensatory mechanism to modulate glucose level in the hippocampal CA1 region and to promote adult neurogenesis in the dentate gyrus. PMID:27651772
Yoho, E R; Thomopoulos, G N; Thalmann, I; Thalmann, R; Schulte, B A
The distribution of organ of Corti protein II (OCP-II) was assessed in the developing and mature gerbil cochlea by light and electron microscopic immunohistochemistry. In the adult cochlea, OCP-II was expressed only in certain epithelial cells which included all supporting cells of the organ of Corti, inner and outer sulcus cells and interdental cells. Inner and outer hair cells lacked immunoreactivity. The highest gold particle labeling density was seen overlying intracellular regions devoid of organelles. In the developing inner ear, OCP-II was first detected at 2 days after birth (DAB) with the strongest staining in immature Deiters, inner phalangeal and pillar cells. Immunostaining intensity increased gradually in cells lying laterally and medially to the more centrally located supporting cells and reached adult levels in all reactive cell types around 18 DAB. The results demonstrated conclusively that OCP-II is a cytosolic protein and fail to support its role as a transcription factor postulated on the basis of its homology with p15 or a role in the control of the cycle as suggested by its near-identity with p19Skp1, a cyclin A/CDK2-associated protein. The continued high level of expression in the mature cochlea argues against OCP-II's involvement in regulating the development and differentiation of epithelial cells. The protein's unique distribution and its gradual increase in expression prior to and during the onset and maturation of hearing, however, support its potential function in the recycling of K+ effluxed from hair cells and neurons back to endolymph.
Jarvers, Christian; Brosch, Tobias; Brechmann, André; Woldeit, Marie L; Schulz, Andreas L; Ohl, Frank W; Lommerzheim, Marcel; Neumann, Heiko
Biologically plausible modeling of behavioral reinforcement learning tasks has seen great improvements over the past decades. Less work has been dedicated to tasks involving contingency reversals, i.e., tasks in which the original behavioral goal is reversed one or multiple times. The ability to adjust to such reversals is a key element of behavioral flexibility. Here, we investigate the neural mechanisms underlying contingency-reversal tasks. We first conduct experiments with humans and gerbils to demonstrate memory effects, including multiple reversals in which subjects (humans and animals) show a faster learning rate when a previously learned contingency re-appears. Motivated by recurrent mechanisms of learning and memory for object categories, we propose a network architecture which involves reinforcement learning to steer an orienting system that monitors the success in reward acquisition. We suggest that a model sensory system provides feature representations which are further processed by category-related subnetworks which constitute a neural analog of expert networks. Categories are selected dynamically in a competitive field and predict the expected reward. Learning occurs in sequentialized phases to selectively focus the weight adaptation to synapses in the hierarchical network and modulate their weight changes by a global modulator signal. The orienting subsystem itself learns to bias the competition in the presence of continuous monotonic reward accumulation. In case of sudden changes in the discrepancy of predicted and acquired reward the activated motor category can be switched. We suggest that this subsystem is composed of a hierarchically organized network of dis-inhibitory mechanisms, dubbed a dynamic control network (DCN), which resembles components of the basal ganglia. The DCN selectively activates an expert network, corresponding to the current behavioral strategy. The trace of the accumulated reward is monitored such that large sudden
Kaufman, G. D.; Shinder, M. E.; Perachio, A. A.
Vestibular compensation is a central nervous system process resulting in recovery of functional movement and control following a unilateral vestibular lesion. Small pressure injections of phosphorothioate 20mer oligonucleotides were used to probe the role of the Fos transcription protein during vestibular compensation in the gerbil brainstem. During isoflurane gas anesthesia, antisense probes against the c-fos mRNA sequence were injected into the medial vestibular and prepositus nuclei unilaterally prior to a unilateral surgical labyrinthectomy. Anionic dyes, which did not interact with the oligonucleotides, were used to mark the injection site and help determine the extent of diffusion. The antiFos oligonucleotide injections reduced Fos expression at the injection site in neurons which normally express Fos after the lesion, and also affected circling behavior induced by hemilabyrinthectomy. With both ipsilateral and contralateral medial vestibular and prepositus nuclei injections, less ipsilateral and more contralateral circling was noted in animals injected with antiFos injections as compared to non-injected controls. The degree of change in these behaviors was dependent upon the side of the injection. Histologically, antiFos injections reduced the number of Fos immunolabeled neurons around the injection site, and increased Fos expression contralaterally. The correlation of the number of neurons with Fos expression to turning behavior was stronger for contralateral versus ipsilateral turns, and for neurons in the caudal and ipsilateral sub-regions of the medial vestibular and prepositus nuclei. The results are discussed in terms of neuronal firing activity versus translational activity based on the asymmetrical expression of the Fos inducible transcription factor in the medial vestibular and prepositus nuclei. Although ubiquitous in the brain, transcription factors like Fos can serve localized and specific roles in sensory-specific adaptive stimuli. Antisense
Pennello, Anthony; Taylor, Justin; Matlack, Robin; Karp, Jonathan; Riggs, James
Analysis of the immune system of spiny mice (Acomys cahirinus) has been limited. Originally grouped with Mus, Acomys has recently been placed closer to Meriones (gerbils). This study compared immunity in Acomys, Mus, and Meriones. Lymphocytes from all rodents examined proliferated in response to mitogen and superantigen stimulation. Only Mus T cells responded to anti-CD3 stimulation. Acomys, like Meriones, and Mus that express xid, did not respond to thymus-independent type 2 antigens. Flow cytometric analyses revealed that T cell-specific MAbs did not bind Acomys or Meriones lymphocytes. The B cell-specific anti-CD45R (B220) MAb detected all rodent B cells and revealed the absence of a CD45R(lo) subset in the peritoneal cavity of Acomys and Meriones. Bone marrow from Acomys and Meriones failed to reconstitute B cell function in SCID mice. Thus, in terms of immunity, Acomys appears to be more similar to Meriones than Mus.
Strelkova, M V; Eliseev, L N; Ponirovskiĭ, E N; Erokhin, P I; Rakitskaia, T A; Valevich, T A; Sysoev, V V; Allenov, V A; Adamishina, T A; Dergacheva, T I
In 1991-1992, 230 isolates were obtained in the Tedzhen oasis and its adjacent desert areas: 172 isolates from great gerbils, 39 from P. papatasi, and 19 from human cutaneous leishmaniasis patients. All the isolates were identified by the isoenzyme polyacrylamide gel electrophoresis by 8 enzymes. The characteristics of Leishmania circulation in the hyperendemic foci of Turkmenistan were similar to those previously studied in the mesoendemic areas of Uzbekistan and Kazakhstan. L. turanica which is non-pathogenic for man prevailed among infected great gerbils in winter, spring, and early summer, making the natural foci epidemiologically safe in that period of time. It was only in August-September that the great gerbil infection rate by L. major appeared to increase, occasionally reaching 100%. Epizootics due to L. major are developing in the presence of L. turanica, therefore most isolates are clone mixtures of L. major and L. turanica. P. papatasi is the only vector in the Tedzhen oasis; there has been strong evidence for its transmission of both L. major and L. turanica, which makes the concept inconsistent that P. papatasi is associated only with L. major. The overall analysis of recent findings of the distribution of L. major in the populations of great gerbils makes it possible to limit the former endemic zoonotic cutaneous leishmaniasis areas to 40 degrees N latitude and the southern borders of Turkmenistan and Uzbekistan. Within this area, the distribution of L. major is uneven and associated basically with rivers, valleys, oases, and foothill desert plains.
Wang, Wei; Wang, Tao; Feng, Wan-Yu; Wang, Zhan-You; Cheng, Mao-Sheng; Wang, Yun-Jie
Ecdysterone (EDS), a common derivative of ecdysteroid, has shown its effects on alleviating cognitive impairment and improving the cognition and memory. However, the mechanisms remain unknown. Using temporal global forebrain ischemia and reperfusion-induced brain injury as a model system, we investigated the roles of EDS in improving cognitive impairment in gerbil. Our results demonstrated that intraperitoneal injection of EDS obviously increased the number of surviving neuron cells by Nissl and neuronal nuclei (NeuN) staining. Indeed, the protecting effects of EDS are because of its ability to prevent the apoptosis of neuron cells as evidenced by TUNEL staining and caspase-3 deactivation in the brain of temporal global forebrain ischemia/reperfusion-treated gerbil. Moreover, EDS administration suppressed the ischemia stimulated activity of astrocytes and microglia cells by inhibiting the production of tumor necrosis alpha (TNF-α) in the brain of gerbil. More importantly, these actions of neurons and astrocytes/microglia cells in response to EDS treatment played pivotal roles in ameliorating the cognitive impairment in the ischemia/reperfusion-injured gerbil. In view of these observations, we not only decipher the mechanisms of EDS in reducing the syndrome of ischemia, but also provide novel perspectives to combat ischemic stroke.
Marshburn, T. H.; Kaufman, G. D.; Purcell, I. M.; Perachio, A. A.
Immunolabeling patterns of the immediate early gene-related protein Fos in the gerbil brainstem were studied following stimulation of the sacculus by both hypergravity and galvanic stimulation. Head-restrained, alert animals were exposed to a prolonged (1 h) inertial vector of 2 G (19.6 m/s2) head acceleration directed in a dorso-ventral head axis to maximally stimulate the sacculus. Fos-defined immunoreactivity was quantified, and the results compared to a control group. The hypergravity stimulus produced Fos immunolabeling in the dorsomedial cell column (dmcc) of the inferior olive independently of other subnuclei. Similar dmcc labeling was induced by a 30 min galvanic stimulus of up to -100 microA applied through a stimulating electrode placed unilaterally on the bony labyrinth overlying the posterior canal (PC). The pattern of vestibular afferent firing activity induced by this galvanic stimulus was quantified in anesthetized gerbils by simultaneously recording from Scarpa's ganglion. Only saccular and PC afferent neurons exhibited increases in average firing rates of 200-300%, suggesting a pattern of current spread involving only PC and saccular afferent neurons at this level of stimulation. These results suggest that alteration in saccular afferent firing rates are sufficient to induce Fos-defined genomic activation of the dmcc, and lend further evidence to the existence of a functional vestibulo-olivary-cerebellar pathway of adaptation to novel gravito-inertial environments.
Gomes, Maria Aparecida; de Oliveira, Dirce Ribeiro; de Freitas, Sabrina Emanuele; de Pinho Viana, Marcelo; Borges, Elizabeth Lage
Studies have shown that symptomatic infection by Giardia lamblia causes acute or chronic diarrhea, dehydration, abdominal pain and malabsorption, leading to undernutrition and weight loss. The aim of the present study was to evaluate the effects of giardiasis and its combination with a low-protein diet on the intestinal absorption of glucose and electrolytes in gerbils. The intestinal absorption of glucose, sodium and potassium was investigated in male gerbils weighing 46-64 g (n≥5). A Tyrode solution containing twice the glucose, sodium and potassium concentration (pH 7.4) was infused through the intestinal loops for 40 min. Glucose absorption was not significantly affected by diet and infection. However, there was a significant increase in sodium absorption in the Giardia-infected group (57.2±6.1, p<0.05) in comparison to the control, low-protein diet and low-protein diet+Giardia-infected groups (8.9±6.5, 2.8±11.1 and 0.8±7.9, respectively; p<0.05). Moreover, potassium was absorbed in the Giardia-infected group (0.45±0.30), while the other groups exhibited potassium secretion. A low-protein diet and Giardia infection had no influence over glucose absorption. However, Giardia infection increased sodium and potassium uptake, suggesting a compensatory mechanism for maintaining homeostasis after likely hypernatremia and hypokalemia caused by the diarrhea that accompanies giardiasis.
Crouch, J J; Sakaguchi, N; Lytle, C; Schulte, B A
We mapped the cellular and subcellular distribution of the Na-K-Cl co-transporter (NKCC) in the adult gerbil inner ear by immunostaining with a monoclonal antibody (MAb T4) generated against human colon NKCC. Heavy immunolabeling was seen in the basolateral plasma membrane of marginal cells in the stria vascularis and dark cells in the vestibular system. Subpopulations of fibrocytes in the cochlear spiral ligament and limbus and underlying the vestibular neurosensory epithelium also stained with moderate to strong intensity, apparently along their entire plasmalemma. Because MAb T4 recognizes both the basolateral secretory (NKCC1) and the apical absorptive (NKCC2) isoforms of the co-transporter, we employed reverse transcription and the polymerase chain reaction (RT-PCR) to explore isoform diversity in inner ear tissues. Using NKCC1 and NKCC2 isoform-specific PCR primers based on mouse and human sequences, only transcripts for NKCC1 were detected in the gerbil inner ear. The presence of abundant NKCC1 in the basolateral plasmalemma of strial marginal and vestibular dark cells confirms conclusions drawn from pharmacological and physiological data. The co-expression of NKCC1 and Na,K-ATPase in highly specialized subpopulations of cochlear and vestibular fibrocytes provides further evidence for their role in recycling K+ leaked or effluxed through hair cells into perilymph back to endolymph, as postulated in current models of inner ear ion homeostasis.
Eads, David; Biggins, Dean E.; Xu, Lei; Liu, Qiyong
Plague, a rodent-associated, flea-borne zoonosis, is one of the most notorious diseases in history. Rates of plague transmission can increase when fleas are abundant. Fleas commonly desiccate and die when reared under dry conditions in laboratories, suggesting fleas will be suppressed during droughts in the wild, thus reducing the rate at which plague spreads among hosts. In contrast, fleas might increase in abundance when precipitation is plentiful, producing epizootic outbreaks during wet years. We tested these hypotheses using a 27-yr data set from two rodents in Inner Mongolia, China: Mongolian gerbils (Meriones unguiculatus) and Daurian ground squirrels (Spermophilus dauricus). For both species of rodents, fleas were most abundant during years preceded by dry growing seasons. For gerbils, the prevalence of plague increased during wet years preceded by dry growing seasons. If precipitation is scarce during the primary growing season, succulent plants decline in abundance and, consequently, herbivorous rodents can suffer declines in body condition. Fleas produce more offspring and better survive when parasitizing food-limited hosts, because starving animals tend to exhibit inefficient behavioral and immunological defenses against fleas. Further, rodent burrows might buffer fleas from xeric conditions aboveground during dry years. After a dry year, fleas might be abundant due to the preceding drought, and if precipitation and succulent plants become more plentiful, rodents could increase in density, thereby creating connectivity that facilitates the spread of plague. Moreover, in wet years, mild temperatures might increase the efficiency at which fleas transmit the plague bacterium, while also helping fleas to survive as they quest among hosts. In this way, dry years could provide context for epizootics of plague in wet years.
Scotti, A L; Kalt, G; Bollag, O; Nitsch, C
Mongolian gerbils are epilepsy prone animals, a trait observable at the behavioural level during the 2nd month of life. As a unique species difference, gerbils express the calcium-binding protein parvalbumin (PV) in the perforant path from the entorhinal cortex to the hippocampus. In this study, we determined the time of appearance of PV in the layer II neurons of the entorhinal cortex and the perforant path terminals in gerbils between post-natal days 30 and 50. Signs of low grade seizures were observed in few animals from P40 onward. PV stain in the entorhinal cortex and perforant path terminals was already detectable at P30, well before the onset of behavioural seizures and did not change with age. It is suggested that the presence of PV in this pathway may be related to the generation early in life of an epileptogenic focus in the limbic forebrain. Altered inhibitory hippocampal circuits have also been suggested as a cause of seizures in the gerbil. Therefore, we quantitated hippocampal GABA-immunoreactive neurons and the PV-immunoreactive subpopulation. A group of gerbils with a high density of stained pyramidal interneurons in CA1 and one lacking PV-stained perikarya could be distinguished at P40 and P50. The density of GABA-immunoreactive nerve cells however, remained the same in both groups and through the ages studied. Thus, perikaryal PV is lost from intact GABAergic nerve cells at the same time as behavioural seizures are observed. The loss of PV from GABAergic neurons may affect their functional properties and be instrumental for the maintainance of behavioural seizures.
Maftoon, Nima; Funnell, W Robert J; Daniel, Sam J; Decraemer, Willem F
We present a finite-element model of the gerbil middle ear that, using a set of baseline parameters based primarily on a priori estimates from the literature, generates responses that are comparable with responses we measured in vivo using multi-point vibrometry and with those measured by other groups. We investigated the similarity of numerous features (umbo, pars-flaccida and pars-tensa displacement magnitudes, the resonance frequency and break-up frequency, etc.) in the experimental responses with corresponding ones in the model responses, as opposed to simply computing frequency-by-frequency differences between experimental and model responses. The umbo response of the model is within the range of variability seen in the experimental data in terms of the low-frequency (i.e., well below the middle-ear resonance) magnitude and phase, the main resonance frequency and magnitude, and the roll-off slope and irregularities in the response above the resonance frequency, but is somewhat high for frequencies above the resonance frequency. At low frequencies, the ossicular axis of rotation of the model appears to correspond to the anatomical axis but the behaviour is more complex at high frequencies (i.e., above the pars-tensa break-up). The behaviour of the pars tensa in the model is similar to what is observed experimentally in terms of magnitudes, phases, the break-up frequency of the spatial vibration pattern, and the bandwidths of the high-frequency response features. A sensitivity analysis showed that the parameters that have the strongest effects on the model results are the Young's modulus, thickness and density of the pars tensa; the Young's modulus of the stapedial annular ligament; and the Young's modulus and density of the malleus. Displacements of the tympanic membrane and manubrium and the low-frequency displacement of the stapes did not show large changes when the material properties of the incus, stapes, incudomallear joint, incudostapedial joint, and
Magnusson, Anna K; Kapfer, Christoph; Grothe, Benedikt; Koch, Ursula
The neurones of the medial superior olive (MSO) are the most temporally sensitive neurones in the brain. They respond to the arrival time difference of sound at the two ears with a microsecond resolution; these interaural time differences are used to localize low-frequency sounds. In addition to the excitatory inputs from each ear, the MSO neurones also receive binaural glycinergic projections, which have a critical role in sound localization processing. Recently, it was shown that the glycinergic input to the MSO undergoes an experience-dependent structural reorganization after hearing onset. To explore the maturation of inhibition during the development of sound localization on a cellular level, glycinergic currents and potentials were measured in gerbil MSO principal cells from postnatal (P) day P12–P25 by whole-cell patch-clamp recordings. The synaptic glycinergic currents accelerated to rapid decay kinetics (∼2 ms) and rise times (∼0.4 ms) after hearing onset, reaching maturity around P17. Since the kinetics of miniature glycinergic currents did not change with age, it is likely that a higher degree of transmitter release synchrony is the underlying mechanism influencing the acceleration of the kinetics. During the same period, the synaptic glycinergic potentials accelerated four-fold, largely as a result of a prominent decrease in input resistance. In accordance with a reorganization of the glycinergic inputs, the evoked peak conductances decreased more than two-fold, together with a three-fold reduction in the frequency of miniature events after hearing onset. These age-dependent changes were absent in animals that had been reared in omni-directional noise, indicating that an experience-dependent pruning of synaptic inputs is important for the maturation of functional inhibition in the MSO. Taken together, these striking developmental adjustments of the glycinergic inhibition in the MSO most probably reflect an adaptation to improve the encoding of
Kaufman, G. D.; Shinder, M. E.; Perachio, A. A.
Three classes of vestibular-related neurons were found in and near the prepositus and medial vestibular nuclei of alert or decerebrate gerbils, those responding to: horizontal translational motion, horizontal head rotation, or both. Their distribution ratios were 1:2:2, respectively. Many cells responsive to translational motion exhibited spatiotemporal characteristics with both response gain and phase varying as a function of the stimulus vector angle. Rotationally sensitive neurons were distributed as Type I, II, or III responses (sensitive to ipsilateral, contralateral, or both directions, respectively) in the ratios of 4:6:1. Four tested factors shaped the response dynamics of the sampled neurons: canal-otolith convergence, oculomotor-related activity, rotational Type (I or II), and the phase of the maximum response. Type I nonconvergent cells displayed increasing gains with increasing rotational stimulus frequency (0.1-2.0 Hz, 60 degrees /s), whereas Type II neurons with convergent inputs had response gains that markedly decreased with increasing translational stimulus frequency (0.25-2.0 Hz, +/-0.1 g). Type I convergent and Type II nonconvergent neurons exhibited essentially flat gains across the stimulus frequency range. Oculomotor-related activity was noted in 30% of the cells across all functional types, appearing as burst/pause discharge patterns related to the fast phase of nystagmus during head rotation. Oculomotor-related activity was correlated with enhanced dynamic range compared with the same category that had no oculomotor-related response. Finally, responses that were in-phase with head velocity during rotation exhibited greater gains with stimulus frequency increments than neurons with out-of-phase responses. In contrast, for translational motion, neurons out of phase with head acceleration exhibited low-pass characteristics, whereas in-phase neurons did not. Data from decerebrate preparations revealed that although similar response types could
Purcell, I. M.; Perachio, A. A.
Anterograde labeling techniques were used to examine peripheral innervation patterns of vestibular efferent neurons in the crista ampullares of the gerbil. Vestibular efferent neurons were labeled by extracellular injections of biocytin or biotinylated dextran amine into the contralateral or ipsilateral dorsal subgroup of efferent cell bodies (group e) located dorsolateral to the facial nerve genu. Anterogradely labeled efferent terminal field varicosities consist mainly of boutons en passant with fewer of the terminal type. The bouton swellings are located predominately in apposition to the basolateral borders of the afferent calyces and type II hair cells, but several boutons were identified close to the hair cell apical border on both types. Three-dimensional reconstruction and morphological analysis of the terminal fields from these cells located in the sensory neuroepithelium of the anterior, horizontal, and posterior cristae were performed. We show that efferent neurons densely innervate each end organ in widespread terminal fields. Subepithelial bifurcations of parent axons were minimal, with extensive collateralization occurring after the axons penetrated the basement membrane of the neuroepithelium. Axonal branching ranged between the 6th and 27th orders and terminal field collecting area far exceeds that of the peripheral terminals of primary afferent neurons. The terminal fields of the efferent neurons display three morphologically heterogeneous types: central, peripheral, and planum. All cell types possess terminal fields displaying a high degree of anisotropy with orientations typically parallel to or within +/-45 degrees of the longitudinal axis if the crista. Terminal fields of the central and planum zones predominately project medially toward the transverse axis from the more laterally located penetration of the basement membrane by the parent axon. Peripheral zone terminal fields extend predominately toward the planum semilunatum. The innervation
Wasan, K M; Najafi, S; Wong, J; Kwong, M; Pritchard, P H
The purpose of this project was to determine the effect of a FM-VP4 when incorporated into the diet or drinking water on plasma lipids, body weight, and hepatic and renal function following chronic oral administration to gerbils. Gerbils were administered water and food daily containing either no FM-VP4 (controls; n=6), 2% or 4% FM-VP4 incorporated into the gerbil diet (n=6 each treatment group) or 2% or 4% FM-VP4 dissolved in the drinking water (n=6 each treatment group). Body weight and food and water intake were monitored weekly. Following 8 weeks of this regiment blood was obtained via a cardiac puncture and all animals were sacrificed humanely. Plasma obtained from this blood was analyzed for total cholesterol, total triglyceride and high-density lipoprotein (HDL)-cholesterol levels by standard enzymatic and precipitation techniques. Low-density lipoprotein (LDL)-cholesterol levels were determined by the Friedewald equation. The plasma was also analyzed for changes in hepatic enzyme (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) and plasma creatinine (renal function) concentrations. 2% and 4% FM-VP4 administration incorporated both into the diet and in the drinking water resulted in a significant decrease in total plasma cholesterol and LDL cholesterol concentration compared to controls. Animals administered 4% FM-VP4 in either their diet or drinking water had significantly lower body weight following the 8 weeks of treatment compared to the other groups. Significant differences in daily water intake was observed in all treatment groups with the exception of the 2% FM-VP4 in diet group compared to controls. Significant differences in daily food intake were observed in gerbils administered 2% FM-VP4 in the drinking water and 4% FM-VP4 in the diet and drinking water groups compared to controls. A significant decrease in total plasma triglyceride concentration was observed in gerbils administered 4% FM-VP4 in their drinking water compared
Park, Jin-A; Park, Joon Ha; Ahn, Ji Hyeon; Kim, Jong-Dai; Won, Moo-Ho; Lee, Choong-Hyun
Antioxidant-like protein-1 (AOP-1) reduces the intracellular level of reactive oxygen species. In the present study, the age-related change in AOP-1 expression in the hippocampus among young, adult and aged gerbils was compared using western blot analysis and immunohistochemistry. The results demonstrated that the protein expression of AOP-1 was gradually and significantly increased in the hippocampus during the normal aging process. In addition, the age-dependent increase in AOP-1 immunoreactivity was also observed in pyramidal neurons of the hippocampus proper; however, in the dentate gyrus, AOP-1 immunoreactivity was not altered during the normal aging process. These results indicated that the expression of AOP-1 is significantly increased in the hippocampus proper, but not in the dentate gyrus, during the normal aging process. PMID:27511601
Yoo, Ki-Yeon; Kim, In Hye; Cho, Jeong-Hwi; Ahn, Ji Hyeon; Park, Joon Ha; Lee, Jae-Chul; Tae, Hyun-Jin; Kim, Dae Won; Kim, Jong-Dai; Hong, Seongkweon; Won, Moo-Ho; Kang, Il Jun
In this study, we tried to verify the neuroprotective effect of Chrysanthemum indicum Linne (CIL) extract, which has been used as a botanical drug in East Asia, against ischemic damage and to explore the underlying mechanism involving the anti-inflammatory approach. A gerbil was given CIL extract for 7 consecutive days followed by bilateral carotid artery occlusion to make a cerebral ischemia/reperfusion model. Then, we found that CIL extracts protected pyramidal neurons in the hippocampal CA1 region (CA1) from ischemic damage using neuronal nucleus immunohistochemistry and Fluoro-Jade B histofluorescence. Accordingly, interleukin-13 immunoreactivities in the CA1 pyramidal neurons of CIL-pretreated animals were maintained or increased after cerebral ischemia/reperfusion. These findings indicate that the pre-treatment of CIL can attenuate neuronal damage/death in the brain after cerebral ischemia/reperfusion via an anti-inflammatory approach. PMID:27073380
Buytaert, Jan A N; Salih, Wasil H M; Dierick, Manual; Jacobs, Patric; Dirckx, Joris J J
In order to improve realism in middle ear (ME) finite-element modeling (FEM), comprehensive and precise morphological data are needed. To date, micro-scale X-ray computed tomography (μCT) recordings have been used as geometric input data for FEM models of the ME ossicles. Previously, attempts were made to obtain these data on ME soft tissue structures as well. However, due to low X-ray absorption of soft tissue, quality of these images is limited. Another popular approach is using histological sections as data for 3D models, delivering high in-plane resolution for the sections, but the technique is destructive in nature and registration of the sections is difficult. We combine data from high-resolution μCT recordings with data from high-resolution orthogonal-plane fluorescence optical-sectioning microscopy (OPFOS), both obtained on the same gerbil specimen. State-of-the-art μCT delivers high-resolution data on the 3D shape of ossicles and other ME bony structures, while the OPFOS setup generates data of unprecedented quality both on bone and soft tissue ME structures. Each of these techniques is tomographic and non-destructive and delivers sets of automatically aligned virtual sections. The datasets coming from different techniques need to be registered with respect to each other. By combining both datasets, we obtain a complete high-resolution morphological model of all functional components in the gerbil ME. The resulting 3D model can be readily imported in FEM software and is made freely available to the research community. In this paper, we discuss the methods used, present the resulting merged model, and discuss the morphological properties of the soft tissue structures, such as muscles and ligaments.
Bresnahan, Kara A; Arscott, Sara A; Khanna, Harjeet; Arinaitwe, Geofrey; Dale, James; Tushemereirwe, Wilberforce; Mondloch, Stephanie; Tanumihardjo, Jacob P; De Moura, Fabiana F; Tanumihardjo, Sherry A
Banana is a staple crop in many regions where vitamin A deficiency is prevalent, making it a target for provitamin A biofortification. However, matrix effects may limit provitamin A bioavailability from bananas. The retinol bioefficacies of unripe and ripe bananas (study 1A), unripe high-provitamin A bananas (study 1B), and raw and cooked bananas (study 2) were determined in retinol-depleted Mongolian gerbils (n = 97/study) using positive and negative controls. After feeding a retinol-deficient diet for 6 and 4 wk in studies 1 and 2, respectively, customized diets containing 60, 30, or 15% banana were fed for 17 and 13 d, respectively. In study 1A, the hepatic retinol of the 60% ripe Cavendish group (0.52 ± 0.13 μmol retinol/liver) differed from baseline (0.65 ± 0.15 μmol retinol/liver) and was higher than the negative control group (0.39 ± 0.16 μmol retinol/liver; P < 0.0065). In study 1B, no groups differed from baseline (0.65 ± 0.15 μmol retinol/liver; P = 0.20). In study 2, the 60% raw Butobe group (0.68 ± 0.17 μmol retinol/liver) differed from the 60% cooked Butobe group (0.87 ± 0.24 μmol retinol/liver); neither group differed from baseline (0.80 ± 0.27 μmol retinol/liver; P < 0.0001). Total liver retinol was higher in the groups fed cooked bananas than in those fed raw (P = 0.0027). Body weights did not differ even though gerbils ate more green, ripe, and raw bananas than cooked, suggesting a greater indigestible component. In conclusion, thermal processing, but not ripening, improves the retinol bioefficacy of bananas. Food matrix modification affects carotenoid bioavailability from provitamin A biofortification targets.
Pickles, A R; Hagan, J J; Jones, D N C; Hendrie, C A
Mongolian gerbils are highly sensitive to manipulations of their social environments. Housing females individually for short periods (in the order of 7-21 days) has been shown to produce robust and reliable impairments of their subsequent social behaviour. These effects are typified by a marked reduction in the social investigation of an unfamiliar male in a neutral arena and/or a marked increases in levels of freezing whilst and only whilst they are being socially investigated (Immobile in contact). These responses demonstrate housing induced impaired motivation to socially interact. These effects have also been shown to be sensitive to treatment with chronic (but not acute) administration of the selective serotonin reuptake inhibitor (SSRI) fluoxetine. It was therefore of interest to know if similar effects would be produced by treatment with the tricyclic antidepressant Imipramine. This mixed NA/5-HT reuptake inhibitor first developed in the 1950's is a commonly used standard in animal models of depression and remains in clinical use today. Female gerbils were individually housed for 7 days or maintained in single-sex groups of 4 for the same period. All animals were then randomly allocated to be administered with either 0, 10 or 20 mg/kg imipramine. Acute administration did not reverse the social impairments produced by the individual housing but did produce non-specific stimulant effects on locomotion in both housing conditions. These social impairments were however reduced after a further 14 days chronic treatment with 10 or 20 mg/kg imipramine and stimulant effects were no longer seen. Following chronic administration in group-housed animals locomotor stimulation was replaced with sedation, which resulted in a reduction in social behaviour. That is, opposite to the effect seen in Individual housed animals. It is therefore concluded that chronic treatment with imipramine serves to increase social behaviour but only in those animals with a pre-existing social
Ferrer, I; Soriano, M A; Vidal, A; Planas, A M
HSP-70 was induced in the gerbil following 20 min of forebrain ischemia. The induction, as revealed with immunohistochemistry, is stronger and longer-lasting in CA3 and dentate gyrus than in CA1. Most neurons in this region, except GABAergic interneurons containing the calcium-binding protein parvalbumin, eventually cease to live as a result of delayed cell death. Double-labeling of inducible HSP-70 and parvalbumin has shown that no co-localization occurs in the hippocampus and neocortex of the gerbil in this model of transient forebrain ischemia. These results show that different thresholds of sensitivity and vulnerability exist for different subpopulations of neurons in the ischemic hippocampus, and suggest that HSP-70 protein induction is probably not essential for the survival of particular neuronal subpopulations subjected to transient ischemia.
Mezei, Orsolya; Chou, Chris N; Kennedy, Kathleen J; Tovar-Palacio, Claudia; Shay, Neil F
Soy intake reduces cholesterol levels, but neither the exact component in soy causing this reduction nor the mechanism by which cholesterol is reduced is known with certainty. In this study, a genetic screen was performed to identify hepatic mRNA in gerbils regulated by soy or soy isoflavones. Gerbils were fed casein, an alcohol-washed soy-based diet (containing low levels of isoflavones), and the soy-based diet supplemented with an isoflavone-containing soy extract. After feeding for 28 d, gerbils were killed, hepatic RNA was isolated, and genes that were differentially expressed in any of the three dietary conditions were identified. Fifteen different mRNA were originally selected, including two mRNA that were studied further and shown to be highly regulated. Messenger RNA levels for both cytochrome P450-2A and phosphoribosylpyrophosphate synthetase-associated protein were up-regulated in a dose-dependent manner when soy replaced casein in the diet at 0, 33, 67 and 100% of original casein levels. A subsequent experiment used purified amino acid mixtures resembling the percentage amino acid composition of soy and casein to ensure that isoflavone-free protein sources could be tested. Using these mixtures, a 2 x 2 x 2 design tested: natural vs. synthetic protein sources, casein- vs. soy-based diets, and isoflavone extract-supplemented or supplement-free diets. This design demonstrated that these two mRNA were again significantly up-regulated more than twofold (P < 0.05) in gerbils fed all diets containing isoflavones. Induction of these two mRNA by soy may be due to the aryl hydrocarbon receptor element in the promoter region of both genes.
Heimesaat, Markus M.; Fischer, André; Plickert, Rita; Wiedemann, Tobias; Loddenkemper, Christoph; Göbel, Ulf B.
Background Gastrointestinal (GI) inflammation in mice and men are frequently accompanied by distinct changes of the GI microbiota composition at sites of inflammation. Helicobacter (H.) pylori infection results in gastric immunopathology accompanied by colonization of stomachs with bacterial species, which are usually restricted to the lower intestine. Potential microbiota shifts distal to the inflammatory process following long-term H. pylori infection, however, have not been studied so far. Methodology/Principal Findings For the first time, we investigated microbiota changes along the entire GI tract of Mongolian gerbils after 14 months of infection with H. pylori B8 wildtype (WT) or its isogenic ΔcagY mutant (MUT) strain which is defective in the type IV secretion system and thus unable to modulate specific host pathways. Comprehensive cultural analyses revealed that severe gastric diseases such as atrophic pangastritis and precancerous transformations were accompanied by elevated luminal loads of E. coli and enterococci in the caecum and together with Bacteroides/Prevotella spp. in the colon of H. pylori WT, but not MUT infected gerbils as compared to naïve animals. Strikingly, molecular analyses revealed that Akkermansia, an uncultivable species involved in mucus degradation, was exclusively abundant in large intestines of H. pylori WT, but not MUT infected nor naïve gerbils. Conclusion/Significance Taken together, long-term infection of Mongolian gerbils with a H. pylori WT strain displaying an intact type IV secretion system leads to distinct shifts of the microbiota composition in the distal uninflamed, but not proximal inflamed GI tract. Hence, H. pylori induced immunopathogenesis of the stomach, including hypochlorhydria and hypergastrinemia, might trigger large intestinal microbiota changes whereas the exact underlying mechanisms need to be further unraveled. PMID:24941045
Rauš Balind, Snežana; Selaković, Vesna; Radenović, Lidija; Prolić, Zlatko; Janać, Branka
Magnetic field as ecological factor has influence on all living beings. The aim of this study was to determine if extremely low frequency magnetic field (ELF-MF, 50 Hz, 0.5 mT) affects oxidative stress in the brain of gerbils submitted to 10-min global cerebral ischemia. After occlusion of both carotid arteries, 3-month-old gerbils were continuously exposed to ELF-MF for 7 days. Nitric oxide and superoxide anion production, superoxide dismutase activity and index of lipid peroxidation were examined in the forebrain cortex, striatum and hippocampus on the 7th (immediate effect of ELF-MF) and 14th day after reperfusion (delayed effect of ELF-MF). Ischemia per se increased oxidative stress in the brain on the 7th and 14th day after reperfusion. ELF-MF also increased oxidative stress, but to a greater extent than ischemia, only immediately after cessation of exposure. Ischemic gerbils exposed to ELF-MF had increased oxidative stress parameters on the 7th day after reperfusion, but to a lesser extent than ischemic or ELF-MF-exposed animals. On the 14th day after reperfusion, oxidative stress parameters in the brain of these gerbils were mostly at the control levels. Applied ELF-MF decreases oxidative stress induced by global cerebral ischemia and thereby reduces possible negative consequences which free radical species could have in the brain. The results presented here indicate a beneficial effect of ELF-MF (50 Hz, 0.5 mT) in the model of global cerebral ischemia. PMID:24586442
Zhang, T; Stanley, S L
The protozoan parasite Entamoeba histolytica causes extensive morbidity and mortality worldwide through intestinal infection and amebic liver abscess. Here we show that vaccination of gerbils, a standard model for amebic liver abscess, with recombinant proteins derived from the 170-kDa galactose-binding adhesin of E. histolytica and the serine-rich E. histolytica protein or a combination of the two recombinant antigens provides excellent protection against subsequent hepatic challenge with virulent E. histolytica trophozoites. PMID:8188384
Park, Sunmin; Kim, Da Sol; Moon, Bo Reum
Since Chungkookjang, a short-term fermented soybean, is known to improve glucose metabolism and antioxidant activity, it may prevent the neurological symptoms and glucose disturbance induced by artery occlusion. We investigated the protective effects and mechanisms of traditional (TFC) and standardized Chungkookjang fermented with Bacillus licheniformis (BLFC) against ischemia/reperfusion damage in the hippocampal CA1 region and against hyperglycemia after transient cerebral ischemia in gerbils. Gerbils were subjected to either an occlusion of the bilateral common carotid arteries for 8 min to render them ischemic or a sham operation. Ischemic gerbils were fed either a 40% fat diet containing 10% of either cooked soybean (CSB), TFC, or BLFC for 28 days. Neuronal cell death and cytokine expression in the hippocampus, neurological deficit, serum cytokine levels, and glucose metabolism were measured. TFC and BLFC contained more isoflavonoid aglycones than CSB. Artery occlusion increased the expressions of IL-1β and TNF-α as well as cell death in the hippocampal CA1 region and induced severe neurological symptoms. CSB, TFC, and BLFC prevented the neuronal cell death and the symptoms such as dropped eyelid, bristling hair, reduced muscle tone and flexor reflex, and abnormal posture and walking patterns, and suppressed cytokine expressions. CSB was less effective than TFC and BLFC. Artery occlusion induced glucose intolerance due to decreased insulin secretion and β-cell mass. TFC and BLFC prevented the impairment of glucose metabolism by artery occlusion. Especially TFC and BLFC increased β-cell proliferation and suppressed the β-cell apoptosis by suppressing TNF-α and IL-1β which in turn decreased cleaved caspase-3 that caused apoptosis. In conclusion, TFC and BLFC may prevent and alleviate neuronal cell death in the hippocampal CA1 region and neurological symptoms and poststroke hyperglycemia in gerbils with artery occlusion. This might be associated with
Park, Sunmin; Kim, Da Sol; Kang, Sunna; Moon, Bo Reum
Since Chungkookjang, a short-term fermented soybean, is known to improve glucose metabolism and antioxidant activity, it may prevent the neurological symptoms and glucose disturbance induced by artery occlusion. We investigated the protective effects and mechanisms of traditional (TFC) and standardized Chungkookjang fermented with Bacillus licheniformis (BLFC) against ischemia/reperfusion damage in the hippocampal CA1 region and against hyperglycemia after transient cerebral ischemia in gerbils. Gerbils were subjected to either an occlusion of the bilateral common carotid arteries for 8 min to render them ischemic or a sham operation. Ischemic gerbils were fed either a 40% fat diet containing 10% of either cooked soybean (CSB), TFC, or BLFC for 28 days. Neuronal cell death and cytokine expression in the hippocampus, neurological deficit, serum cytokine levels, and glucose metabolism were measured. TFC and BLFC contained more isoflavonoid aglycones than CSB. Artery occlusion increased the expressions of IL-1β and TNF-α as well as cell death in the hippocampal CA1 region and induced severe neurological symptoms. CSB, TFC, and BLFC prevented the neuronal cell death and the symptoms such as dropped eyelid, bristling hair, reduced muscle tone and flexor reflex, and abnormal posture and walking patterns, and suppressed cytokine expressions. CSB was less effective than TFC and BLFC. Artery occlusion induced glucose intolerance due to decreased insulin secretion and β-cell mass. TFC and BLFC prevented the impairment of glucose metabolism by artery occlusion. Especially TFC and BLFC increased β-cell proliferation and suppressed the β-cell apoptosis by suppressing TNF-α and IL-1β which in turn decreased cleaved caspase-3 that caused apoptosis. In conclusion, TFC and BLFC may prevent and alleviate neuronal cell death in the hippocampal CA1 region and neurological symptoms and poststroke hyperglycemia in gerbils with artery occlusion. This might be associated with
Braack, L E; Horak, I G; Jordaan, L C; Segerman, J; Louw, J P
Red veld rats (Aethomys chrysophilus) and bushveld gerbils (Tatera leucogaster) were trapped at monthly intervals, when possible, over a 2-year period, in the southern Kruger National Park, Mpumalanga Province. Forty-six specimens of each species were caught, euthenased and microscopically examined for fleas, lice, ticks and mites. Clear differences existed between the two rodent hosts in infestation intensity and also parasite species. The flea, Xenopsylla brasiliensis, commonly and exclusively utilized red veld rats, whereas Xenopsylla frayi was common and specific to bushveld gerbils. T. leucogaster were commonly infested with the lice Hoplopleura biseriata and Polyplax biseriata, while only a single A. chrysophilus hosted the louse, Hoplopleura patersoni. Red veld rats harboured small numbers of the immature stages of Haemaphysalis leachi/spinulosa and relatively large numbers of Rhipicephalus simus. The larvae of R. simus were irregularly collected from February to September and the nymphs from March to November. Bushveld gerbils hosted fewer ticks than did the rats, with a single specimen of H. leachi/spinulosa and low numbers of immature Hyalomma truncatum, the latter erratically present from June to October. Miles were abundant on both rodent hosts, A. chrysophilus hosting 13 species in six families, and T. leucogaster hosting 12 species representing seven families, with clear differences in mite assemblages between the two rodents. As the rats and gerbils were collected from the same trap lines at the same times, the differences in species composition and infestation intensity of their parasites, suggest that immunological behavioural or other segregating mechanisms are in operation to maintain discrete parasite assemblages.
Ahn, Ji Yun; Yan, Bing Chun; Park, Joon Ha; Ahn, Ji Hyeon; Lee, Dae Hwan; Kim, In Hye; Cho, Jeong-Hwi; Chen, Bai Hui; Lee, Jae-Chul; Cho, Young Shin; Shin, Myoung Chul; Cho, Jun Hwi; Hong, Seongkweon; Won, Moo-Ho; Kim, Sung Koo
Lacosamide, which is a novel antiepileptic drug, has been reported to exert various additional therapeutic effects. The present study investigated the neuroprotective effects of lacosamide against transient cerebral ischemia-induced neuronal cell damage in the hippocampal cornu ammonis (CA)-1 region of a gerbil model. Neuronal Nuclei immunohistochemistry demonstrated that pre- and post-surgical treatment (5 min ischemia) with 25 mg/kg lacosamide protected CA1 pyramidal neurons in the lacosamide-treated-ischemia-operated group from ischemic injury 5 days post-ischemia, as compared with gerbils in the vehicle-treated-ischemia-operated group. Furthermore, treatment with 25 mg/kg lacosamide markedly attenuated the activation of astrocytes and microglia in the ischemic CA1 region at 5 days post-ischemia. The results of the present study suggested that pre- and post-surgical treatment of the gerbils with lacosamide was able to protect against transient cerebral ischemic injury-induced CA1 pyramidal neuronal cell death in the hippocampus. In addition, the neuroprotective effects of lacosamide may be associated with decreased activation of glial cells in the ischemic CA1 region.
Sloto, Ronald A.
, which is about 190 feet north of the source area. A much larger area was affected by chlorobenzene than benzene. Chlorobenzene concentrations decreased in the source area and increased at and beyond the site boundary. Water from four wells in and northeast of the source area sampled in 2008 exceeded the 5.06 ug/L ARAR for 1,1-dichloroethane (1,1-DCA). Increases in 1,1-DCA concentration between pre-shutdown samples collected in July 2006 and samples collected in February 2008 ranged from 0.4 to 20 ug/L. Water from two wells in the source area sampled in 2008 exceeded the 175 ug/L ARAR for total xylene. The 1,1-DCA and xylene plumes appear to extend in an east-northeast direction from the source area. Large drawdowns in the Upper Merion Reservoir during droughts in 1998 and 2001 affected water levels in the Chester Valley and at the Henderson Road Site, except for well HR-17-170. After the drought of 2001, water levels in the Chester Valley showed a protracted recovery lasting from September 2001 until June 2005 (46 months). Water-level data were evaluated temporally for 1997-2008 and spatially for (1) June 16, 2003, when the extraction wells were pumping at the full rate prior to the start of the June 2003 shutdown test; (2) July 10, 2006, during the period of reduced pumping after the June 2003 shutdown test; and (3) February 25-29, 2008, when the extraction wells were not pumping. Except for well HR-5-195, wells were categorized as shallow, intermediate-depth, and deep wells. The potentiometric surface for shallow wells did not appear to be affected by pumping of the extraction wells. The general direction of ground-water flow was to the north. The potentiometric surface for intermediate-depth wells showed a cone of depression when the extraction wells were pumping at the full rate but did not show a cone of depression when the extraction wells were pumping at the reduced rate. The ground-water-flow direction was toward the north and northeast, similar to
Arumugam, Sridhar; Wei, Junfei; Liu, Zhuyun; Abraham, David; Bell, Aaron; Bottazzi, Maria Elena; Hotez, Peter J.; Zhan, Bin; Lustigman, Sara; Klei, Thomas R.
Background The Brugia malayi Bm-103 and Bm-RAL-2 proteins are orthologous to Onchocerca volvulus Ov-103 and Ov-RAL-2, and which were selected as the best candidates for the development of an O. volvulus vaccine. The B. malayi gerbil model was used to confirm the efficacy of these Ov vaccine candidates on adult worms and to determine whether their combination is more efficacious. Methodology and Principle Findings Vaccine efficacy of recombinant Bm-103 and Bm-RAL-2 administered individually, concurrently or as a fusion protein were tested in gerbils using alum as adjuvant. Vaccination with Bm-103 resulted in worm reductions of 39%, 34% and 22% on 42, 120 and 150 days post infection (dpi), respectively, and vaccination with Bm-RAL-2 resulted in worm reductions of 42%, 22% and 46% on 42, 120 and 150 dpi, respectively. Vaccination with a fusion protein comprised of Bm-103 and Bm-RAL-2 resulted in improved efficacy with significant reduction of worm burden of 51% and 49% at 90 dpi, as did the concurrent vaccination with Bm-103 and Bm-RAL-2, with worm reduction of 61% and 56% at 90 dpi. Vaccination with Bm-103 and Bm-RAL-2 as a fusion protein or concurrently not only induced a significant worm reduction of 61% and 42%, respectively, at 150 dpi, but also significantly reduced the fecundity of female worms as determined by embryograms. Elevated levels of antigen-specific IgG were observed in all vaccinated gerbils. Serum from gerbils vaccinated with Bm-103 and Bm-RAL-2 individually, concurrently or as a fusion protein killed third stage larvae in vitro when combined with peritoneal exudate cells. Conclusion Although vaccination with Bm-103 and Bm-RAL-2 individually conferred protection against B. malayi infection in gerbils, a more consistent and enhanced protection was induced by vaccination with Bm-103 and Bm-RAL-2 fusion protein and when they were used concurrently. Further characterization and optimization of these filarial vaccines are warranted. PMID:27045170
Gannon, Bryan M; Pixley, Kevin V; Tanumihardjo, Sherry A
Background: Vitamin A (VA) and zinc deficiencies are prevalent. Maize is a common staple, and milling affects nutrient and nutrient-modifier profiles.Objective: We investigated the interaction of maize milling methods (i.e., whole grain compared with refined) in male Mongolian gerbils aged 29-35 d with conventionally bred provitamin A-biofortified (orange) or white maize on VA and zinc status.Methods: Study 1 (n = 67) was a 2 × 3 milling (whole compared with refined) by VA [no-vitamin A placebo group (VA-), orange, and VA-supplemented group (VA+)] design, with 4 wk of VA depletion followed by six 4-wk treatments (n = 10/treatment). Study 2 (n = 33) was a 2 × 2 milling-by-zinc [no-zinc placebo group (Zn-) compared with zinc-supplemented group (Zn+)] design, including 2 wk of VA depletion followed by four 3-wk treatments (n = 8-9/treatment). For study 1, positive and negative control groups were given supplemental VA at equimolar amounts to β-carotene equivalents consumed by the orange groups (74 ± 5 nmol/d) or placebo, respectively. For study 2, positive and negative control groups were given 152 μg Zn/d or placebo, respectively.Results: Milling significantly affected zinc concentration, providing 44-45% (whole grain) or 9-14% (refined) NRC requirements. In study 1, orange maize improved liver VA concentrations (mean ± SD: 0.28 ± 0.08 μmol/g) compared with the white maize groups (0.072 ± 0.054 μmol/g). Provitamin A bioefficacy was similar. In study 2, neither zinc nor milling influenced liver retinol. Refined Zn- gerbils weighed less than others by day 14 (46.6 ± 7.1 compared with 56.5 ± 3.5 g, respectively; P < 0.0001). Milling affected pancreas zinc concentrations (refined Zn-: 21.1 ± 1.8 μg Zn/g; whole Zn-: 32.5 ± 5.8 μg Zn/g).Conclusions: Whole-grain intake improved zinc and did not affect provitamin A bioefficacy. Other factors affected by milling (e.g., shelf life, preference, aflatoxin fractioning) need to be considered to maximize health.
Chevret, P; Denys, C; Jaeger, J J; Michaux, J; Catzeflis, F M
Spiny mice of the genus Acomys traditionally have been classified as members of the Murinae, a subfamily of rodents that also includes rats and mice with which spiny mice share a complex set of morphological characters, including a unique molar pattern. The origin and evolution of this molar pattern, documented by many fossils from Southern Asia, support the hypothesis of the monophyly of Acomys and all other Murinae. This view has been challenged by immunological studies that have suggested that Acomys is as distantly related to mice (Mus) as are other subfamilies (e.g., hamsters: Cricetinae) of the muroid rodents. We present molecular evidence derived from DNA.DNA hybridization data that indicate that the spiny mouse Acomys and two African genera of Murinae, Uranomys and Lophuromys, constitute a monophyletic clade, a view that was recently suggested on the basis of dental characters. However, our DNA.DNA hybridization data also indicate that the spiny mice (Acomys) are more closely related to gerbils (Gerbillinae) than to the true mice and rats (Murinae) with which they have been classified. Because Acomys and the brush-furred mice Uranomys and Lophuromys share no derived morphological characters with the Gerbillinae, their murine morphology must have evolved by convergence, including the molar pattern previously considered to support the monophyly of the Murinae.
Chevret, P; Denys, C; Jaeger, J J; Michaux, J; Catzeflis, F M
Spiny mice of the genus Acomys traditionally have been classified as members of the Murinae, a subfamily of rodents that also includes rats and mice with which spiny mice share a complex set of morphological characters, including a unique molar pattern. The origin and evolution of this molar pattern, documented by many fossils from Southern Asia, support the hypothesis of the monophyly of Acomys and all other Murinae. This view has been challenged by immunological studies that have suggested that Acomys is as distantly related to mice (Mus) as are other subfamilies (e.g., hamsters: Cricetinae) of the muroid rodents. We present molecular evidence derived from DNA.DNA hybridization data that indicate that the spiny mouse Acomys and two African genera of Murinae, Uranomys and Lophuromys, constitute a monophyletic clade, a view that was recently suggested on the basis of dental characters. However, our DNA.DNA hybridization data also indicate that the spiny mice (Acomys) are more closely related to gerbils (Gerbillinae) than to the true mice and rats (Murinae) with which they have been classified. Because Acomys and the brush-furred mice Uranomys and Lophuromys share no derived morphological characters with the Gerbillinae, their murine morphology must have evolved by convergence, including the molar pattern previously considered to support the monophyly of the Murinae. PMID:8475093
Magari, Hirohito; Shimizu, Yasuhito; Inada, Ken-ichi; Enomoto, Shotaro; Tomeki, Tatsuji; Yanaoka, Kimihiko; Tamai, Hideyuki; Arii, Kenji; Nakata, Hiroya; Oka, Masashi; Utsunomiya, Hirotoshi; Tsutsumi, Yutaka; Tsukamoto, Tetsuya; Tatematsu, Masae; Ichinose, Masao E-mail: email@example.com
The effect of the selective COX-2 inhibitor, etodolac, on Helicobacter pylori (Hp)-associated stomach carcinogenesis was investigated in Mongolian gerbils (MGs). Hp-infected MGs were fed for 23 weeks with drinking water containing 10 ppm N-methyl-N-nitrosourea. They were then switched to distilled water and placed on a diet containing 5-30 mg/kg/day etodolac for 30 weeks. We found that etodolac dose-dependently inhibited the development of gastric cancer, and no cancer was detected at a dose of 30 mg/kg/day. Etodolac did not affect the extent of inflammatory cell infiltration or oxidative DNA damage, but it significantly inhibited mucosal cell proliferation and dose-dependently repressed the development of intestinal metaplasia in the stomachs of Hp-infected MGs. These results suggest that COX-2 is a key molecule in inflammation-mediated stomach carcinogenesis and that chemoprevention of stomach cancer should be possible by controlling COX-2 expression or activity.
Park, Joon Ha; Lee, Choong Hyun; Kim, In Hye; Ahn, Ji Hyeon; Cho, Jeong-Hwi; Yan, Bing Chun; Lee, Jae-Chul; Lee, Tae Hun; Seo, Jeong Yeol; Cho, Jun Hwi; Won, Moo-Ho; Kang, Il-Jun
Glucose is a main energy source for normal brain functions. Glucokinase (GK) plays an important role in glucose metabolism as a glucose sensor, and GK activity is modulated by glucokinase regulatory protein (GKRP). In this study, we examined the changes of GK and GKRP immunoreactivities in the gerbil hippocampus after 5 min of transient global cerebral ischemia. In the sham-operated-group, GK and GKRP immunoreactivities were easily detected in the pyramidal neurons of the stratum pyramidale of the hippocampus. GK and GKRP immunoreactivities in the pyramidal neurons were distinctively decreased in the hippocampal CA1 region (CA), not CA2/3, 3 days after ischemia-reperfusion (I-R). Five days after I-R, GK and GKRP immunoreactivities were hardly detected in the CA1, not CA2/3, pyramidal neurons; however, at this point in time, GK and GKRP immunoreactivities were newly expressed in astrocytes, not microglia, in the ischemic CA1. In brief, GK and GKRP immunoreactivities are changed in pyramidal neurons and newly expressed in astrocytes in the ischemic CA1 after transient cerebral ischemia. These indicate that changes of GK and GKRP expression may be related to the ischemia-induced neuronal damage/death.
Custodio, Ana Maria G; Santos, Fernanda C A; Campos, Silvana G P; Vilamaior, Patricia S L; Góes, Rejane M; Taboga, Sebastião R
Different from the classic view, the prostate is not a gland exclusive to the male, also being an organ of the female genital system presenting morphofunctional similarity between human and rodent. Thus structural, ultrastructural, morphometric-stereological features of the female prostate (Skene's paraurethral gland) and steroid serological levels were evaluated during young, adult, and senile ages in the Mongolian gerbil. The morphofunctional precocity of the female gland in comparison with the male gland occurring in young gland is probably associated with the female circulating steroid levels. The hormonal imbalance in senesce coincides with its susceptibility to histopathological lesions, such as epithelial hypertrophy, metaplasia, and intraepithelial neoplasia. Differently than that of males, the aging degeneration of the female gland involves the accumulation of lipofuscin granules. However, the alterations in senile prostate did not damage its functionality. These analyses reinforce the use of this experimental model for the comprehension of glandular morphofunctional aspects with special attention to senescence. Thus, the appreciation of this organ becomes relevant to avoid future discomfort to women's health.
Mollace, Vincenzo; Iannone, Michelangelo; Muscoli, Carolina; Palma, Ernesto; Granato, Teresa; Modesti, Andrea; Nisticò, Robert; Rotiroti, Domenicantonio; Salvemini, Daniela
Background Overproduction of free radical species has been shown to occur in brain tissues after ischemia-reperfusion injury. However, most of free radical scavengers known to antagonize oxidative damage (e.g. superoxide dismutase, catalase), are unable to protect against ischemia-reperfusion brain injury when given in vivo, an effect mainly due to their difficulty to gain access to brain tissues. Here we studied the effect of a low molecular weight superoxide dismutase mimetic (M40401) in brain damage subsequent to ischemia-reperfusion injury in Mongolian gerbils. Results In animals undergoing ischemia-reperfusion injury, neuropathological and ultrastructural changes were monitored for 1–7 days either in the presence or in the absence of M40401 after bilateral common carotid artery occlusion (BCCO). Administration of M40401 (1–40 mg/kg, given i.p. 1 h after BCCO) protected against post-ischemic, ultrastructural and neuropathological changes occurring within the hippocampal CA1 area. The protective effect of M40401 was associated with a significant reduction of the levels of malondialdehyde (MDA; a marker of lipid peroxidation) in ischemic brain tissues after ischemia-reperfusion. Conclusion Taken together, these results demonstrate that M40401 provides protective effects when given early after the induction of ischemia-reperfusion of brain tissues and suggest the possible use of such compounds in the treatment of neurological dysfunction subsequent to cerebral flow disturbances. PMID:12809567
Wang, Qun; Tompkins, Kenneth D; Simonyi, Agnes; Korthuis, Ronald J; Sun, Albert Y; Sun, Grace Y
Increased production of reactive oxygen species (ROS) following cerebral ischemia-reperfusion (I/R) is an important underlying cause for neuronal injury leading to delayed neuronal death (DND). In this study, apocynin, a specific inhibitor for NADPH oxidase, was used to test whether suppression of ROS by the NADPH oxidase inhibitor can protect against ischemia-induced ROS generation and decrease DND. Global cerebral ischemia was induced in gerbils by a 5-min occlusion of bilateral common carotid arteries (CCA). Using measurement of 4-hydroxy-2-nonenal (HNE) as a marker for lipid peroxidation, apocynin (5 mg/kg body weight) injected i.p. 30 min prior to ischemia significantly attenuated the early increase in HNE in hippocampus measured at 3 h after I/R. Apocynin also protected against I/R-induced neuronal degeneration and DND, oxidative DNA damage, and glial cell activation. Taken together, the neuroprotective effects of apocynin against ROS production during early phase of I/R and subsequent I/R-induced neuronal damage provide strong evidence that inhibition of NADPH oxidase could be a promising therapeutic mechanism to protect against stroke damage in the brain.
Dekanski, Dragana; Selaković, Vesna; Piperski, Vesna; Radulović, Zeljka; Korenić, Andrej; Radenović, Lidija
The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral ischemia/reperfusion brain injury are well known. Mediterranean diet, rich in olive products, is associated with lower incidence of cardiovascular disease, cancer, inflammation and stroke. In this study, the possible neuroprotective effect of standardized dry olive leaf extract (OLE) is investigated for the first time. Transient global cerebral ischemia in Mongolian gerbils was used to investigate the OLE effects on different parameters of oxidative stress and neuronal damage in hippocampus. The biochemical measurements took place at different time points (80min, 2, 4 and 24h) after reperfusion. The effects of applied OLE were compared with effects of quercetin, a known neuroprotective plant flavonoid. Pretreatment with OLE (100mg/kg, per os) significantly inhibited production of superoxide and nitric oxide, decreased lipid peroxidation, and increased superoxide dismutase activity in all time points examined. Furthermore, OLE offered histological improvement as seen by decreasing neuronal damage in CA1 region of hippocampus. The effects of applied OLE were significantly higher than effects of quercetin (100mg/kg, per os). Our results indicate that OLE exerts a potent neuroprotective activity against neuronal damage in hippocampus after transient global cerebral ischemia, which could be attributed to its antioxidative properties.
CHO, YOUNG SHIN; CHO, JUN HWI; SHIN, BICH-NA; CHO, GEUM-SIL; KIM, IN HYE; PARK, JOON HA; AHN, JI HYEON; OHK, TAEK GEUN; CHO, BYUNG-RYUL; KIM, YOUNG-MYEONG; HONG, SEONGKWEON; WON, MOO-HO; LEE, JAE-CHUL
Glucokinase (GK) is involved in the control of blood glucose homeostasis. In the present study, the effect of ischemic preconditioning (IPC) on the immunoreactivities of GK and its regulatory protein (GKRP) following 5 min of transient cerebral ischemia was investigated in gerbils. The gerbils were randomly assigned to four groups (sham-operated group, ischemia-operated group, IPC + sham-operated group and IPC + ischemia-operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia, followed by 1 day of recovery. In the ischemia-operated group, a significant loss of neurons was observed in the stratum pyramidale (SP) of the hippocampal CA1 region (CA1) at 5 days post-ischemia; however, in the IPC+ischemia-operated group, the neurons in the SP were well protected. Following immunohistochemical investigation, the immunoreactivities of GK and GKRP in the neurons of the SP were markedly decreased in the CA1, but not the CA2/3, from 2 days post-ischemia, and were almost undetectable in the SP 5 days post-ischemia. In the IPC + ischemia-operated group, the immunoreactivities of GK and GKRP in the SP of the CA1 were similar to those in the sham-group. In brief, the findings of the present study demonstrated that IPC notably maintained the immunoreactivities of GK and GKRP in the neurons of the SP of CA1 following ischemia-reperfusion. This indicated that GK and GKRP may be necessary for neuron survival against transient cerebral ischemia. PMID:26134272
Prosser-Loose, Erin J; Verge, Valerie M K; Cayabyab, Francisco S; Paterson, Phyllis G
Previously it has been demonstrated that protein-energy malnutrition (PEM) impairs habituation in the open field test following global ischemia. The present study examined the hypothesis that PEM exerts some of its deleterious effects on functional outcome by altering the post-ischemic expression of the plasticity-associated genes brain-derived neurotrophic factor (BDNF), its receptor tropomyosin-related kinase B (trkB), and growth-associated protein-43 (GAP-43). Male, Mongolian gerbils (11-12 wk) were randomized to either control diet (12.5% protein) or PEM (2% protein) for 4 wk, and then underwent 5 min bilateral common carotid artery occlusion or sham surgery. Tympanic temperature was maintained at 36.5 ± 0.5°C during surgery. Brains collected at 1, 3 and 7 d post-surgery were processed by in-situ hybridization or immunofluorescence. BDNF and trkB mRNA expression was increased in hippocampal CA1 neurons after ischemia at all time points and was not significantly influenced by diet. However, increased trkB protein expression after ischemia was exacerbated by PEM at 7 d in the CA1 region. Post-ischemic GAP-43 protein increased at 3 and 7 d in the CA1 region, and PEM intensified this response and extended it to the CA3 and hilar regions. PEM exerted these effects without exacerbating CA1 neuron loss caused by global ischemia. The findings suggest that PEM increases the stress response and/or hyper-excitability in the hippocampus after global ischemia. Nutritional care appears to have robust effects on plasticity mechanisms important to recovery after brain ischemia.
Park, Seung Min; Park, Chan Woo; Lee, Tae-Kyeong; Cho, Jeong Hwi; Park, Joon Ha; Lee, Jae-Chul; Chen, Bai Hui; Shin, Bich-Na; Ahn, Ji Hyeon; Tae, Hyun-Jin; Shin, Myoung Cheol; Ohk, Taek Geun; Cho, Jun Hwi; Won, Moo-Ho; Choi, Soo Young; Kim, In Hye
Ischemic preconditioning (IPC) is a condition of sublethal transient global ischemia and exhibits neuroprotective effects against subsequent lethal ischemic insult. We, in this study, examined the neuroprotective effects of IPC and its effects on immunoreactive changes of antioxidant enzymes including superoxide dismutase (SOD) 1 and SOD2, catalase (CAT) and glutathione peroxidase (GPX) in the gerbil hippocampal CA1 region after transient forebrain ischemia. Pyramidal neurons of the stratum pyramidale (SP) in the hippocampal CA1 region of animals died 5 days after lethal transient ischemia without IPC (8.6% (ratio of remanent neurons) of the sham-operated group); however, IPC prevented the pyramidal neurons from subsequent lethal ischemic injury (92.3% (ratio of remanent neurons) of the sham-operated group). SOD1, SOD2, CAT and GPX immunoreactivities in the sham-operated animals were easily detected in pyramidal neurons in the stratum pyramidale (SP) of the hippocampal CA1 region, while all of these immunoreactivities were rarely detected in the stratum pyramidale at 5 days after lethal transient ischemia without IPC. Meanwhile, their immunoreactivities in the sham-operated animals with IPC were similar to (SOD1, SOD2 and CAT) or higher (GPX) than those in the sham-operated animals without IPC. Furthermore, their immunoreactivities in the stratum pyramidale of the ischemia-operated animals with IPC were steadily maintained after lethal ischemia/reperfusion. Results of western blot analysis for SOD1, SOD2, CAT and GPX were similar to immunohistochemical data. In conclusion, IPC maintained or increased the expression of antioxidant enzymes in the stratum pyramidale of the hippocampal CA1 region after subsequent lethal transient forebrain ischemia and IPC exhibited neuroprotective effects in the hippocampal CA1 region against transient forebrain ischemia. PMID:27630689
Rodríguez Cruz, Yamila; Mengana Támos, Yuneidys; Muñoz Cernuda, Adriana; Subirós Martines, Nelvis; González-Quevedo, Alina; Sosa Testé, Iliana; García Rodríguez, Julio César
Vascular illness of the brain constitutes the third cause of death and the first cause of disability in Cuba and many other countries. Presently, no medication has been registered as a neuroprotector. Neuroprotection with intranasal Neuro-EPO (EPO, erythropoietin) has emerged as a multifunctional therapy that plays a significant role in neural survival and functional recovery in an animal model of stroke. On the other hand, there is limited access to the brain through the blood brain barrier (BBB) for intravenously applied EPO, and the high EPO dosages needed to obtain a protective effect increase the danger of elevated hematocrit levels and practically exclude chronic or subchronic treatment with EPO. A promising approach has been recently developed with a nonerythropoietic variant of EPO, Neuro-EPO, with low sialic acid content, a very short plasma half-life, and without erythropoietic activity, probably similar to endogenous brain EPO. The objective of this work was to determine the neuroprotective effect of intranasal Neuro-EPO in comparison with the human recombinant EPO injected intraperitoneally in the acute phase of cerebral ischemia, employing the common carotid artery occlusion model in gerbils. Neuro-EPO has demonstrated a better neuroprotective effect, evidenced through increased viability, improvements of the neurological state and cognitive functions, as well as protection of the CA3 region of the hippocampus, temporal cortex, and the thalamus. In conclusion, the intranasal application of Neuro-EPO has a better neuroprotective effect than intraperitoneal EPO, evidenced by the significant improvement of neurological, cognitive, and histological status in the animal model of stroke employed.
Park, Seung Min; Park, Chan Woo; Lee, Tae-Kyeong; Cho, Jeong Hwi; Park, Joon Ha; Lee, Jae-Chul; Chen, Bai Hui; Shin, Bich-Na; Ahn, Ji Hyeon; Tae, Hyun-Jin; Shin, Myoung Cheol; Ohk, Taek Geun; Cho, Jun Hwi; Won, Moo-Ho; Choi, Soo Young; Kim, In Hye
Ischemic preconditioning (IPC) is a condition of sublethal transient global ischemia and exhibits neuroprotective effects against subsequent lethal ischemic insult. We, in this study, examined the neuroprotective effects of IPC and its effects on immunoreactive changes of antioxidant enzymes including superoxide dismutase (SOD) 1 and SOD2, catalase (CAT) and glutathione peroxidase (GPX) in the gerbil hippocampal CA1 region after transient forebrain ischemia. Pyramidal neurons of the stratum pyramidale (SP) in the hippocampal CA1 region of animals died 5 days after lethal transient ischemia without IPC (8.6% (ratio of remanent neurons) of the sham-operated group); however, IPC prevented the pyramidal neurons from subsequent lethal ischemic injury (92.3% (ratio of remanent neurons) of the sham-operated group). SOD1, SOD2, CAT and GPX immunoreactivities in the sham-operated animals were easily detected in pyramidal neurons in the stratum pyramidale (SP) of the hippocampal CA1 region, while all of these immunoreactivities were rarely detected in the stratum pyramidale at 5 days after lethal transient ischemia without IPC. Meanwhile, their immunoreactivities in the sham-operated animals with IPC were similar to (SOD1, SOD2 and CAT) or higher (GPX) than those in the sham-operated animals without IPC. Furthermore, their immunoreactivities in the stratum pyramidale of the ischemia-operated animals with IPC were steadily maintained after lethal ischemia/reperfusion. Results of western blot analysis for SOD1, SOD2, CAT and GPX were similar to immunohistochemical data. In conclusion, IPC maintained or increased the expression of antioxidant enzymes in the stratum pyramidale of the hippocampal CA1 region after subsequent lethal transient forebrain ischemia and IPC exhibited neuroprotective effects in the hippocampal CA1 region against transient forebrain ischemia.
Park, Joon Ha; Park, Ok kyu; Cho, Jeong-Hwi; Chen, Bai Hui; Kim, In Hye; Ahn, Ji Hyeon; Lee, Jae-Chul; Yan, Bing Chun; Yoo, Ki-Yeon; Lee, Choong Hyun; Hwang, In Koo; Kwon, Seung-Hae; Lee, Yun Lyul; Won, Moo-Ho; Choi, Jung Hoon
Tanshinone I (TsI) is an important lipophilic diterpene extracted from Danshen (Radix Salvia miltiorrhizae) and has been used in Asia for the treatment of cerebrovascular diseases such as ischemic stroke. In this study, we examined the neuroprotective effect of TsI against ischemic damage and its neuroprotective mechanism in the gerbil hippocampal CA1 region (CA1) induced by 5 min of transient global cerebral ischemia. Pre-treatment with TsI protected pyramidal neurons from ischemic damage in the stratum pyramidale (SP) of the CA1 after ischemia-reperfusion. The pre-treatment with TsI increased the immunoreactivities and protein levels of anti-inflammatory cytokines [interleukin (IL)-4 and IL-13] in the TsI-treated-sham-operated-groups compared with those in the vehicle-treated-sham-operated-groups; however, the treatment did not increase the immunoreactivities and protein levels of pro-inflammatory cytokines (IL-2 and tumor necrosis factor-α). On the other hand, in the TsI-treated-ischemia-operated-groups, the immunoreactivities and protein levels of all the cytokines were maintained in the SP of the CA1 after transient cerebral ischemia. In addition, we examined that IL-4 injection into the lateral ventricle did not protect pyramidal neurons from ischemic damage. In conclusion, these findings indicate that the pre-treatment with TsI can protect against ischemia-induced neuronal death in the CA1 via the increase or maintenance of endogenous inflammatory cytokines, and exogenous IL-4 does not protect against ischemic damage.
During April 19-May 19, 2013 it was realized 30-days flight of Russian biosatellite Bion-M1. The main goal of this flight was to study effects of microgravity upon behavior and structural-functional state of different physiological systems of vertebrates. The folloving species were accommodated aboard of biosatellite: 45 mice C57bl/6, 8 Mongolian gerbils Meriones unguiculatus, 15 lizards, i.e. geckos Chondrodctylus turneri Gray, and fish Oreochromis mossambicus. The selection and traing of mice for the flight and ground-based control experiments was carried out at the Research Institute of Mitoengineering by Moscow State University. The protocols for animals care and reserch were revised and adopted by Bioethics Commission of above mentioned institute (decision on November 01, 2013, N35). The final version of Bion-M1 Scientific Reseach Program and protocols for separate experiments were discussed and adopted by Biomedical Ethics Commission of Institute of Biomedical Problems (decision on April 4, 2014, N317). The IMBP Commission has a status of Physiological Section of Russian Bioethics Committee by Russian Commision for UNESCO affairs and follows the Russian Bioethical Guidelines for Experiments in Aerospace and Naval Medicine and other national and international rules including COSPAR International Policy and Guidelines for Animal Care and Use in Space-born Research. Because US-scientists were the main partners in mice investigations the decision of IMBP Biomedical Commission related to Bion-M1 project was sended for information to Institutional Animal Care and Use Committee of NASA Ames Research Center. Postflight estimation of mice was done by Russian veterinary with the participation of NASA Chief veterinary.
Sager, H; Moret, C Steiner; Müller, N; Staubli, D; Esposito, M; Schares, G; Hässig, M; Stärk, K; Gottstein, B
The protozoan parasite Neospora caninum is one of the most important abortifacient organisms in cattle worldwide. The dog is known to act as definitive host although its potential role as infection source for bovines still remains unelucidated. The aim of the present study was to compile initial epidemiological data on the prevalence and incidence of N. caninum in Swiss dogs acting as definitive hosts. Thus, 249 Swiss dogs were investigated coproscopically in monthly intervals over a period of 1 year. A total of 3289 fecal samples was tested by the flotation technique. Among these, 202 were shown to contain Sarcocystis sp. (6.1%), 149 Cystoisospora sp. (=Isospora sp.; 4.5%) and 25 Hammondia/Neospora-like oocysts (HNlO) (0.7%). All but one sample containing HNlO were from different dogs; one dog shed HNlO at two subsequent time points. Calculation of the yearly incidence for HNlO resulted in the surprisingly high value of 9.2%. Farm dogs exhibited a higher incidence for HNlO than urban family dogs. Thirteen out of the 25 HNlO-samples showed sporulation after 5 days incubation at room temperature. HNlO were further differentiated by species-specific PCR. However, all HNlO-samples were negative for N. caninum, Hammondia heydorni and Toxoplasma gondii. One reason may be the low oocyst density found in most fecal samples, which did not permit us to carry out PCR under optimal conditions. Three out of the 25 HNlO-cases contained enough oocysts to allow further enrichment and purification by the flotation technique. Subsequently, twenty to fifty sporulated HNlO-oocysts were orally administered to Meriones unguiculatus. All gerbils were seronegative for N. caninum at 5 weeks p.i. A N. caninum-seroprevalence of 7.8% was determined by ELISA upon 1132 serum samples collected from dogs randomly selected by veterinarians among their clinical patients.
Trattner, Barbara; Gravot, Céline Marie; Grothe, Benedikt; Kunz, Lars
Neuronal activity is energetically costly, but despite its importance, energy production and consumption have been studied in only a few neurone types. Neuroenergetics is of special importance in auditory brainstem nuclei, where neurones exhibit various biophysical adaptations for extraordinary temporal precision and show particularly high firing rates. We have studied the development of energy metabolism in three principal nuclei of the superior olivary complex (SOC) involved in precise binaural processing in the Mongolian gerbil (Meriones unguiculatus). We used immunohistochemistry to quantify metabolic markers for energy consumption (Na+/K+-ATPase) and production (mitochondria, cytochrome c oxidase activity and glucose transporter 3 (GLUT3)). In addition, we calculated neuronal ATP consumption for different postnatal ages (P0–90) based upon published electrophysiological and morphological data. Our calculations relate neuronal processes to the regeneration of Na+ gradients perturbed by neuronal firing, and thus to ATP consumption by Na+/K+-ATPase. The developmental changes of calculated energy consumption closely resemble those of metabolic markers. Both increase before and after hearing onset occurring at P12–13 and reach a plateau thereafter. The increase in Na+/K+-ATPase and mitochondria precedes the rise in GLUT3 levels and is already substantial before hearing onset, whilst GLUT3 levels are scarcely detectable at this age. Based on these findings we assume that auditory inputs crucially contribute to metabolic maturation. In one nucleus, the medial nucleus of the trapezoid body (MNTB), the initial rise in marker levels and calculated ATP consumption occurs distinctly earlier than in the other nuclei investigated, and is almost completed by hearing onset. Our study shows that the mathematical model used is applicable to brainstem neurones. Energy consumption varies markedly between SOC nuclei with their different neuronal properties. Especially for the
Azimi-Zonooz, A; Kawa, C B; Dowell, C D; Olivera, B M
In the mammalian central nervous system, transient global ischemia of specific duration causes selective degeneration of CA1 pyramidal neurons in hippocampus. Many of the ischemia-induced pathophysiologic cascades that destroy the neurons are triggered by pre- and postsynaptic calcium entry. Consistent with this, many calcium channel blockers have been shown to be neuroprotective in global models of ischemia. omega-Conotoxin MVIIA, a selective N-type VGCC blocker isolated from the venom of Conus magus, protects CA1 neurons in the rat model of global ischemia, albeit transiently. The mechanism by which this peptide renders neuroprotection is unknown. We performed high-resolution receptor autoradiography with the radiolabeled peptide and observed highest binding in stratum lucidum of CA3 subfield, known to contain inhibitory neurons potentially important in the pathogenesis of delayed neuronal death. This finding suggested that the survival of stratum lucidum inhibitory neurons might be the primary event, leading to CA1 neuroprotection after ischemia. Testing of this hypothesis required the reproduction of its neuroprotective effects in the gerbil model of global ischemia. Surprisingly, we found that omega-MVIIA did not attenuate CA1 hippocampal injury after 5 min of cerebral ischemia in gerbil. Possible reasons are discussed. Lastly, we show that the peptide can be used as a synaptic marker in assessing short and long-term changes that occur in hippocampus after ischemic injury.
Bénéré, E; VAN Assche, T; Cos, P; Maes, L
This study investigated the molecular and biological variation among different Giardia duodenalis assemblages. In vitro growth and susceptibility to albendazole, fenbendazole, flubendazole, metronidazole, tinidazole and furazolidone was studied for laboratory (AI: WB, AII: G1 and B: GS/M-83-H7) and 6 field isolates of assemblage subtype AI, AII, B and EIII. Additionally, isolates of the 3 assemblages were evaluated in the gerbil upon 3-day oral treatment with albendazole (6 mg/kg), flubendazole (5 mg/kg) and metronidazole (20 mg/kg). Assemblage AI grew significantly faster than all other assemblage subtypes, which showed comparable generation times. The assemblage A laboratory strains displayed altered in vitro drug susceptibilities compared to their matching AI or AII field isolate. No variation in drug susceptibility was observed between field isolates of assemblages A and E. However, assemblage A laboratory strains were more susceptible to the benzimidazoles and less susceptible to the nitro-imidazoles and furazolidone than the assemblage B laboratory strain. In the gerbil, no markedly different drug susceptibilities were observed. In conclusion, the Giardia assemblage subtype can be associated with differences in growth characteristics rather than in drug susceptibility.
Perez, Ana P S; Biancardi, Manoel F; Vilamaior, Patricia S L; Góes, Rejane M; Santos, Fernanda C A; Taboga, Sebastião R
There is an increasing variety of endocrine disrupting chemicals (EDCs) either with (anti)estrogenic or (anti)androgenic potential widely present in the environment. These xenosteroids may mimic endogenous steroid hormones disrupting the homeostasis of physiological pathways and leading to several disturbances, especially in tissues highly dependent on steroid hormones such as the prostate. Taking this into account, this comparative study aimed to verify the potential of ethinylestradiol (EE) and testosterone acting as ECDs on the prostate of both male and female adult gerbils exposed to these agents during the embryonic phase. Consequently, pregnant gerbils were treated either with 10 μg/kg/day of EE or with a single dose of 1 mg of testosterone cypionate. The pups that were born 6-8 days after testosterone exposure and the pups that were born after 3 days of EE exposure were allowed to grow but were sacrificed within 4 months. Serological, morphological, stereological, and immunohistochemical analyses were used. Overall, the results showed that both sexes exposed to testosterone and EE during gestation had a prostatic gland with an increased stromal and epithelial and a reduced luminal compartment. Moreover, we observed that glands affected with prostatic intraepithelial neoplasia showed intense stromal reshuffling. In conclusion, although these alterations were observed in both sexes, more relevant to this study was the differential responsiveness of males and females exposed to these different drugs. Whereas the EE affected males more, the testosterone was more harmful to the females.
Teste, Iliana Sosa; Tamos, Yuneidys Mengana; Cruz, Yamila Rodríguez; Cernada, Adriana Muñoz; Rodríguez, Janette Cruz; Martínez, Nelvis Subirós; Antich, Rosa Maria Coro; González-Quevedo, Alina; Rodríguez, Julio Cesar García
Cerebrovascular disease is the third leading cause of death and the leading cause of disability in Cuba and in several developed countries. A possible neuroprotective agent is the rHu-EPO, whose effects have been demonstrated in models of brain ischemia. The Neuro-EPO is a derivative of the rHu-EPO that avoids the stimulation of erythropoiesis. The aim of this study was to determine the Neuro-EPO delivery into the central nervous system (CNS) to exert a neuroprotective effect in cerebral ischemia model of the Mongolian gerbil. The Neuro-EPO in a rate of 249.4 UI every 8 hours for 4 days showed 25% higher viability efficacy (P > 0.01), improving neurological score and behavior of the spontaneous exploratory activity, the preservation of CA3 areas of the hippocampus, the cortex, and thalamic nuclei in the focal ischemia model of the Mongolian gerbil. In summary, this study, the average dose-used Neuro-EPO (249.4 UI/10 μL/every 8 hours for 4 days), proved to be valid indicators of viability, neurological status, and spontaneous exploratory activity, being significantly lower than that reported for the systemically use of the rHu-EPO as a neuroprotectant. Indeed, up to 12 h after brain ischemia is very positive Neuro-EPO administration by the nasal route as a candidate for neuroprotection.
Immunohistochemical localization of nerve growth factor, glial fibrillary acidic protein and ciliary neurotrophic factor in mesencephalon, rhombencephalon, and spinal cord of developing mongolian gerbil.
Park, Il-Kwon; Lee, Kyoug-Youl; Song, Chi-Won; Kwon, Hyo-Jung; Park, Mi-Sun; Lee, Mi-Young; Lee, Keun-Jwa; Jeong, Young-Gil; Lee, Chul-Ho; Ha, Kwon-Soo; Rhee, Man-Hee; Lee, Kang-Yi; Kim, Moo-Kang
The distribution of the nerve growth factor (NGF), the glial fibrillary acidic protein (GFAP) and the ciliary neurotrohic factor (CNTF) was performed in coronal sections of the mesencephalon, rhombencephalon and spinal cord in the developing Mongolian gerbils. Generally, NGF specifically recognizes neurons with the NGF receptor, whereas GFAP does the glia, and CNTF does the motor neurons. The receptor expression was examined separately in gerbils between embryonic days 15 (E15) and postnatal weeks 3 (PNW 3). The NGF-IR was first observed in the spinal cord at E21, which might be related to the maturation. The GFAP reactivity was peaked at the postnatal days 2 (PND2), while the highest CNTF-reaction was expressed at PNW 2. The GFAP stains were observed in the aqueduct and the spinal cord, which appeared to project laterally at E19. The CNTF was observed only after the birth and found in both the neurons and neuroglia of the substantia nigra, mesencephalon, cerebellum and the spinal cord from PND1 to PNW3. These results suggest that NGF, GFAP and CNTF are important for the development of the neurons and the neuroglia in the central nervous system at the late prenatal and postnatal stages.
Teste, Iliana Sosa; Tamos, Yuneidys Mengana; Cruz, Yamila Rodríguez; Cernada, Adriana Muñoz; Rodríguez, Janette Cruz; Martínez, Nelvis Subirós; Antich, Rosa Maria Coro; González-Quevedo, Alina; Rodríguez, Julio Cesar García
Cerebrovascular disease is the third leading cause of death and the leading cause of disability in Cuba and in several developed countries. A possible neuroprotective agent is the rHu-EPO, whose effects have been demonstrated in models of brain ischemia. The Neuro-EPO is a derivative of the rHu-EPO that avoids the stimulation of erythropoiesis. The aim of this study was to determine the Neuro-EPO delivery into the central nervous system (CNS) to exert a neuroprotective effect in cerebral ischemia model of the Mongolian gerbil. The Neuro-EPO in a rate of 249.4 UI every 8 hours for 4 days showed 25% higher viability efficacy (P > 0.01), improving neurological score and behavior of the spontaneous exploratory activity, the preservation of CA3 areas of the hippocampus, the cortex, and thalamic nuclei in the focal ischemia model of the Mongolian gerbil. In summary, this study, the average dose-used Neuro-EPO (249.4 UI/10 μL/every 8 hours for 4 days), proved to be valid indicators of viability, neurological status, and spontaneous exploratory activity, being significantly lower than that reported for the systemically use of the rHu-EPO as a neuroprotectant. Indeed, up to 12 h after brain ischemia is very positive Neuro-EPO administration by the nasal route as a candidate for neuroprotection. PMID:22701364
Kim, Dong Won; Cho, Jeong-Hwi; Cho, Geum-Sil; Kim, In Hye; Park, Joon Ha; Ahn, Ji Hyeon; Chen, Bai Hui; Shin, Bich-Na; Tae, Hyun-Jin; Hong, Seongkweon; Cho, Jun Hwi; Kim, Young-Myeong; Won, Moo-Ho; Lee, Jae-Chul
It is well known that neurons in the dentate gyrus (DG) of the hippocampus are resistant to short period of ischemia. Hyperthermia is a proven risk factor for cerebral ischemia and can produce more extensive brain damage related with mortality rates. The aim of this study was to examine the effect of hyperthermic conditioning (H) on neuronal death, gliosis and expressions of SODs as anti-oxidative enzymes in the gerbil DG following 5 min-transient cerebral ischemia. The animals were randomly assigned to 4 groups: 1) (N+sham)-group was given sham-operation with normothermia (N); 2) (N+ischemia)-group was given 5 min-transient ischemia with N; 3) (H+sham)-group was given sham-operation with H; and 4) (H+ischemia)-group was given 5 min-transient cerebral ischemia with H. H (39±0.5°C) was induced by subjecting the animals to a heating pad for 30 min before and during the operation. In the (N+ischemia)-groups, a significant neuronal death was observed in the polymorphic layer (PL) from 1 day after ischemia-reperfusion. In the (H+ischemia)-groups, neuronal death was also observed in the PL from 1day post-ischemia; the degree of the neuronal death was severer than that in the (N+ischemia)-groups. In addition, we examined the gliosis of astrocytes and microglia using anti-glial fibrillary acidic protein (GFAP) and anti- ionized calcium-binding adapter molecule 1 (Iba-1). GFAP(+) and Iba-1(+) glial cells were much more activated in the (H+ischemia)-groups than those in the (N+ischemia)-groups. On the other hand, immunoreactivities and levels of SOD1 rather than SOD2 were significantly lower in the (H+ischemia)-groups than those in the (N+ischemia)-groups. In brief, on the basis of our findings, we suggest that cerebral ischemic insult with hyperthermic conditioning brings up severer neuronal damage and gliosis in the polymorphic layer through reducing SOD1 expression rather than SOD2 expression in the DG.
Soomro, Majid Hussain; Shi, Ruihan; She, Ruiping; Yang, Yifei; Wang, Tongtong; Wu, Qiaoxing; Li, Heng; Hao, Wenzhuo
Hepatitis E virus (HEV) infection has been associated with a wide range of extrahepatic manifestations, so this study was designed to examine the effect and role of HEV on structural and molecular changes in the testicular tissues of Mongolian gerbils experimentally infected with swine HEV. HEV RNA was first detected in testis at 14 day post inoculation and reached a peak between 28 to 42 days later with viral load between 3.12 logs g-¹ to 6.23 logs g-¹ by PCR assays. Microscopic changes showed vacuolation, sloughing of germ cells, formation of multinuclear giant cells, degeneration, necrosis of tubules and damaged blood-testis barrier was observed through transmission electron microscopy. HEV ORF2 antigen was detected in the sperm cell cytoplasm along with decrease in relative protein of zonula occludens-1 through immunohistochemistry. HEV ORF3 antigen and ZO-1 protein was detectable through western blot. Lower (P<0.05) serum testosterone and higher (P<0.05) blood urea nitrogen (BUN) level was observed in inoculated Mongolian gerbils. Likewise, increased (P<0.05) germ cell apoptosis rate was detected with significant increased expression of Fas-L, Fas in HEV inoculated groups at each time points. Up-regulation (P < 0.05 or P < 0.01) in mRNA level of Fas-L, Fas, Bax, Bcl-2 and caspase-3 were seen in HEV RNA positive testes. Our study demonstrated that after experimental inoculation, HEV can be detected in testis tissues and viral proteins produce structural and molecular changes that in turn disrupt the blood-testis barrier and induce germ cell apoptosis. This article is protected by copyright. All rights reserved.
Perez, Ana Paula Silva; Biancardi, Manoel Francisco; Góes, Rejane Maira; dos Santos, Fernanda Alcântara; Taboga, Sebastião Roberto
Steroids perform significant functions in prostatic development and growth, so that interferences of this equilibrium may predispose the gland to the development of diseases during the life. Embryonic and neonatal exposure to xenoestrogens, many of them with endocrine-disrupting potential, has been related to the induction of disturbances in reproductive system organs. Thus, this study aimed to analyse morphological and immunocytochemical aspects of prostate in both male and female adult gerbils either exposed to ethinylestradiol during the prenatal phase (pregnant females received 10 μg/kg, by gavage) (EE group) or exposed to testosterone (1 mg/kg) during the postnatal period (EE/T group). Serological analysis revealed a rise in estradiol levels in adult males and females of the EE group. A higher incidence of prostatic intraepithelial neoplasia (PIN) was observed in the male and female prostate of the treated groups, besides an increase in collagen and reticular fibres. Immunocytochemistry showed an increase in prostatic epithelial cells immunoreactive to AR and a presence of a smooth muscle layer, evidenced by α actin, in injured regions this way absent in prostatic epithelial buds. These pieces of evidence suggest that the alterations verified in the prostate in adulthood of both sexes may be due to the high oestrogen levels. Either males or females of the EE/T group showed normalized estradiol levels, although prostatic lesions could be observed. While the prostatic gland of male gerbils was more affected than the female prostate, this study showed that the exposure to EE during this critical period of development disrupts the prostate of both sexes in terms of prostatic lesions. PMID:21314741
Malek, Michal; Duszczyk, Malgorzata; Zyszkowski, Marcin; Ziembowicz, Apolonia; Salinska, Elzbieta
Anoxic brain injury resulting from cardiac arrest is responsible for approximately two-thirds of deaths. Recent evidence suggests that increased oxygen delivered to the brain after cardiac arrest may be an important factor in preventing neuronal damage, resulting in an interest in hyperbaric oxygen (HBO) therapy. Interestingly, increased oxygen supply may be also reached by application of normobaric oxygen (NBO) or hyperbaric air (HBA). However, previous research also showed that the beneficial effect of hyperbaric treatment may not directly result from increased oxygen supply, leading to the conclusion that the mechanism of hyperbaric prevention of brain damage is not well understood. The aim of our study was to compare the effects of HBO, HBA and NBO treatment on gerbil brain condition after transient forebrain ischemia, serving as a model of cardiac arrest. Thereby, we investigated the effects of repetitive HBO, HBA and NBO treatment on hippocampal CA1 neuronal survival, brain temperature and gerbils behavior (the nest building), depending on the time of initiation of the therapy (1, 3 and 6 h after ischemia). HBO and HBA applied 1, 3 and 6 h after ischemia significantly increased neuronal survival and behavioral performance and abolished the ischemia-evoked brain temperature increase. NBO treatment was most effective when applied 1 h after ischemia; later application had a weak or no protective effect. The results show that HBO and HBA applied between 1 and 6 h after ischemia prevent ischemia-evoked neuronal damage, which may be due to the inhibition of brain temperature increase, as a result of the applied rise in ambient pressure, and just not due to the oxygen per se. This perspective is supported by the finding that NBO treatment was less effective than HBO or HBA therapy. The results presented in this paper may pave the way for future experimental studies dealing with pressure and temperature regulation.
Kim, Min Joung; Cho, Jun Hwi; Cho, Jeong-Hwi; Park, Joon Ha; Ahn, Ji Hyeon; Tae, Hyun-Jin; Cho, Geum-Sil; Yan, Bing Chun; Hwang, In Koo; Lee, Choong Hyun; Bae, Eun Joo; Won, Moo-Ho; Lee, Jae-Chul
Hyperthermia can exacerbate the brain damage produced by ischemia. In the present study, we investigated the effects of hyperthermia before and during ischemia-reperfusion on neuronal damage and glial changes in the gerbil hippocampus following transient cerebral ischemia using cresyl violet staining, NeuN immunohistochemistry and Fluoro-Jade B histofluorescence staining. The animals were randomly assigned to 4 groups: (1) sham-operated animals with normothermia (normothermia + sham group); (2) ischemia-operated animals with normothermia (normothermia + ischemia group); (3) sham-operated animals with hyperthermia (hyperthermia + sham group); and (4) ischemia-operated animals with hyperthermia (hyperthermia + ischemia group). Hyperthermia (39.5 ± 0.2°C) was induced by exposing the gerbils to a heating pad connected to a rectal thermistor for 30 min before and during ischemia-reperfusion. In the normothermia+ischemia groups, a significant delayed neuronal death was observed in the stratum pyramidale (SP) of the hippocampal CA1 region (CA1) 5 days after ischemia-reperfusion. In the hyperthermia+ischemia groups, neuronal death in the SP of the CA1 occurred at 1 day post-ischemia, and neuronal death was observed in the SP of the CA2/3 region at 2 days post-ischemia. In addition, we examined activations of astrocytes and microglia using immunohistochemistry for anti-glial fibrillary acidic protein (GFAP) and anti-ionized calcium-binding adapter molecule 1 (Iba-1). GFAP-positive astrocytes and Iba-1-positive microglia in the ischemic hippocampus were activated much earlier and much more accelerated in the hyperthermia+ischemia groups than those in the normothermia+ischemia groups. Based on our findings, we suggest that an experimentally hyperthermic pre-condition before cerebral ischemic insult produces more extensive neuronal damage and glial activation in the ischemic hippocampus.
Yu, Dong-Kun; Yoo, Ki-Yeon; Shin, Bich Na; Kim, In Hye; Park, Joon Ha; Lee, Choong Hyun; Choi, Jung Hoon; Cho, Yong-Jun; Kang, Il-Jun; Kim, Young-Myeong; Won, Moo-Ho
Although there are many studies on ischemic brain damage in the gerbil, which is a good model of transient cerebral ischemia, studies on neuronal damage according to the duration of ischemia-reperfusion (I-R) time are limited. We carried out neuronal damage in the gerbil hippocampus after various durations of I-R (5, 10, 15 and 20 min) using Fluoro-Jade B (F-J B, a maker for neuronal degeneration) histofluorescence as well as cresyl violet (CV) staining. The changes of CV positive ((+)) neurons were well detected in the hippocampal CA1 region, not in the other regions. F-J B histofluorescence staining showed apparent neuronal damage in all the hippocampal subregions. In the CA1, most of the pyramidal neurons of the stratum pyramidale (SP) were stained with F-J B (about 100/mm(2) in a section), and F-J B(+) neurons in the other ischemia-groups were not changed. In the CA2, a few F-J B(+) neurons were detected in the SP of the 5 min ischemia-group, and F-J B(+) neurons were gradually increased with the longer time of ischemia: in the 20 min ischemia-group, the mean number of F-J B(+) neurons was about 85/mm(2) in a section. In the CA3, some F-J B(+) neurons were observed only in the SP of the 20 min ischemia-group. In the dentate gyrus, some F-J B positive neurons were detected only in the polymorphic layer (PL) of the 5 min ischemia-group, and the number of F-J B(+) neurons were gradually increased with the longer ischemic time. Our findings indicate that F-J B histofluorescence showed a very high quality of neuronal damage in all the hippocampal subregions.
Oral immunization with an attenuated vaccine strain of Salmonella typhimurium expressing the serine-rich Entamoeba histolytica protein induces an antiamebic immune response and protects gerbils from amebic liver abscess.
Zhang, T; Stanley, S L
Attenuated salmonellae represent attractive candidates for the delivery of foreign antigens by oral vaccination. In this report, we describe the high-level expression of a recombinant fusion protein containing the serine-rich Entamoeba histolytica protein (SREHP), a protective antigen derived from virulent amebae, and a bacterially derived maltose-binding protein (MBP) in an attenuated strain of Salmonella typhimurium. Mice and gerbils immunized with S. typhimurium expressing SREHP-MBP produced mucosal immunoglobulin A antiamebic antibodies and serum immunoglobulin G antiamebic antibodies. Gerbils vaccinated with S typhimurium SREHP-MBP were protected against amebic liver abscess, the most common extraintestinal complication of amebiasis. Our findings indicate that the induction of mucosal and immune responses to the amebic SREHP antigen is dependent on the level of SREHP-MBP expression in S. typhimurium and establish that oral vaccination with SREHP can produce protective immunity to invasive amebiasis. PMID:8613356
High salt diets dose-dependently promote gastric chemical carcinogenesis in Helicobacter pylori-infected Mongolian gerbils associated with a shift in mucin production from glandular to surface mucous cells.
Kato, Sosuke; Tsukamoto, Tetsuya; Mizoshita, Tsutomu; Tanaka, Harunari; Kumagai, Toshiko; Ota, Hiroyoshi; Katsuyama, Tsutomu; Asaka, Masahiro; Tatematsu, Masae
Intake of salt and salty food is known as a risk factor for gastric carcinogenesis. To examine the dose-dependence and the mechanisms underlying enhancing effects, Mongolian gerbils were treated with N-methyl-N-nitrosourea (MNU), Helicobacter pylori and food containing various concentrations of salt, and were sacrificed after 50 weeks. Among gerbils treated with MNU and H. pylori, the incidences of glandular stomach cancers were 15% in the normal diet group and 33%, 36% and 63% in the 2.5%, 5% and 10% NaCl diet groups, showing dose-dependent increase (p < 0.01). Intermittent intragastric injection of saturated NaCl solution, in contrast, did not promote gastric carcinogenesis. In gerbils infected with H. pylori, a high salt diet was associated with elevation of anti-H. pylori antibody titers, serum gastrin levels and inflammatory cell infiltration in a dose-dependent fashion. Ten percent NaCl diet upregulated the amount of surface mucous cell mucin (p < 0.05), suitable for H. pylori colonization, despite no increment of MUC5AC mRNA, while H. pylori infection itself had an opposing effect, stimulating transcription of MUC6 and increasing the amount of gland mucous cell mucin (GMCM). High salt diet, in turn, decreased the amount of GMCM, which acts against H. pylori infection. In conclusion, the present study demonstrated dose-dependent enhancing effects of salt in gastric chemical carcinogenesis in H. pylori-infected Mongolian gerbils associated with alteration of the mucous microenvironment. Reduction of salt intake could thus be one of the most important chemopreventive methods for human gastric carcinogenesis.
Deming, D M; Boileau, A C; Lee, C M; Erdman, J W
Current dietary guidelines recommend a decrease in fat intake and an increase in fiber consumption. Decreased bioavailability (BV) of carotenoids is thought to be associated with both of these recommendations. A 2 x 4 factorial design was used to test the effects of dietary fat level at 10 or 30% of total energy and fiber type using no fiber, silica, citrus pectin or oat gum (7 g/100 g) on beta-carotene (betaC) BV in 4- to 5-wk-old Mongolian gerbils. We assessed BV as both accumulation of betaC and bioconversion of betaC to vitamin A (VA) in tissues. A VA- and betaC-deficient diet was fed for 1 wk followed by one of eight isocaloric, semipurified diets supplemented with carrot powder [ approximately 1 microgram betaC, 0.5 microgram alpha-carotene (alphaC)/kJ diet] for 2 wk (n = 12/group). Increasing dietary fat resulted in higher VA (P: = 0.074) and lower betaC (P: = 0.0001) stores in the liver, suggesting that consumption of high fat diets enhances conversion of betaC to VA. The effect of soluble fiber on hepatic VA storage was dependent on fiber type. Consumption of citrus pectin resulted in lower hepatic VA stores and higher hepatic betaC stores compared with all other groups, suggesting less conversion of betaC to VA. In contrast, consumption of oat gum resulted in hepatic VA and betaC stores that were higher (P = 0.012) and lower (P = 0.022), respectively, than those of citrus pectin-fed gerbils. The level of dietary fat consumed with soluble fiber had no interactive effects on hepatic VA, betaC or alphaC stores. Results demonstrate that betaC BV is independently affected by dietary fat level and type of soluble fiber, and suggest that these dietary components modulate postabsorptive conversion of betaC to VA. This study confirms the negative effects of citrus pectin on betaC BV, and suggests that oat gum does not adversely affect betaC BV.
Iijima, T; Sawa, H; Shiokawa, Y; Saito, I; Ishii, H; Nakamura, Z; Sankawa, H
Thromboxane A2 accumulates in the hippocampus after global ischemia and may play a key role in postischemic hypoperfusion. Thromboxane synthetase inhibitor (OKY-046) inhibits the accumulation of thromboxane A2 and promotes prostacycline production. Therefore, we set out to determine whether the inhibition of thromboxane synthesis would ameriolate postischemic neuronal death. Three groups of six Mongolian gerbils were subjected to different treatments: untreated control, untreated ischemia, and treated ischemia. Immediately after forebrain ischemia, OKY-046 (10 mg/kg) was injected intraperitoneally into the treated group. After 7 days of survival, the histopathology of the brain was examined. Pyramidal cell density in the CA1 sector in the treated group was 147 +/- 70 nuclei/mm (mean +/- SD), which was significantly (p < 0.05) higher than than in the untreated group (33 +/- 10 (nuclei/mm). The findings were 231 +/- 7 nuclei/mm for the control group. No significant difference was seen in the profile of temporal muscle temperature before and after ischemia between the groups. Ultrastructurally, the vessels in the CAI sector showed lumen patency in the treated group, whereas occluded vessels with an extended perivascular space were observed in the untreated group. Thromboxane synthetase inhibitor thus partly ameliorates the selective vulnerability of the hippocampus after forebrain ischemia, suggesting that thromboxane A2 is involved in the development of delayed neuronal death, independently of any thermal effect.
Chatterjee, Aparajita; Bandini, Giulia; Motari, Edwin
Enteric protozoan parasites, which are spread by the fecal-oral route, are important causes of diarrhea (Giardia duodenalis) and amebic dysentery (Entamoeba histolytica). Cyst walls of Giardia and Entamoeba have a single layer composed of fibrils of β-1,3-linked GalNAc and β-1,4-linked GlcNAc (chitin), respectively. The goal here was to determine whether hand sanitizers that contain ethanol or isopropanol as the active microbicide might reduce transmission of these parasites. We found that treatment with these alcohols with or without drying in a rotary evaporator (to model rapid evaporation of sanitizers on hands) kills 85 to 100% of cysts of G. duodenalis and 90 to 100% of cysts of Entamoeba invadens (a nonpathogenic model for E. histolytica), as shown by nuclear labeling with propidium iodide and failure to excyst in vitro. Alcohols with or without drying collapsed the cyst walls of Giardia but did not collapse the cyst walls of Entamoeba. To validate the in vitro results, we showed that treatment with alcohols eliminated oral infection of gerbils by 1,000 G. duodenalis cysts, while a commercial hand sanitizer (Purell) killed E. invadens cysts that were directly applied to the hands. These results suggest that expanded use of alcohol-based hand sanitizers might reduce the transmission of Giardia and Entamoeba. PMID:26282413
Remmerswaal, Danielle; Muris, Peter; Huijding, Jorg
Using an experimental approach, we examined the effects of verbal information as provided by the mothers on children's fear of real novel animals. Mothers of children aged 8 to 12 years (N=47) were shown a cage containing a pair of exotic rodents (i.e., Mongolian gerbils) and then received either positive or negative information about these animals. Mothers were told that their child would have to approach the animals and had the opportunity to prepare their children for this confrontation. Results showed that mothers spontaneously passed over the information they had received to their children. Most importantly, this information to some extent determined children's fear reactions towards the animals. That is, whereas no clear effects of information were found on subjective fear ratings, the data did indicate that children of mothers in the negative information condition were more reluctant to approach the animals as compared to children of mothers who had received positive information. The findings provide further support for the idea that verbal information as provided by parents may induce fear in their offspring.
Araki, T; Kato, H; Kogure, K
1. We investigated the alterations in binding sites of three major second messengers, phorbol 12,13-dibutyrate, inositol 1,4,5-trisphosphate and forskolin following transient cerebral ischemia in gerbils, and examined the effects of a novel vinca alkaloid derivative, vinconate against the alterations in the binding of the second messengers following ischemia. 2. Transient cerebral ischemia produced by bilateral occlusion of the common carotid arteries was induced for 10 min, and intraperitoneal administration of vinconate (100 mg/kg and 300 mg/kg) was given 10 min before ischemia. 3. Morphological study indicated that transient ischemia can produce severe neuronal damage in striatum, hippocampal CA1 sector and hippocampal CA3 sector. 4. Transient cerebral ischemia caused the postischemic alterations in the binding of three second messengers. 5. The postischemic alterations in the binding of second messengers were ameliorated by pretreatment with vinconate. This effect was especially observed in the striatum which was most vulnerable to ischemia. 6. These findings are discussed in relation to the mechanism of ischemic neuronal damage.
Choi, In-Young; Hwang, Lakkyong; Jin, Jun-Jang; Ko, Il-Gyu; Kim, Sung-Eun; Shin, Mal-Soon; Shin, Key-Moon; Kim, Chang-Ju; Park, Sung-Wook; Han, Jin-Hee; Yi, Jae-Woo
Cerebral ischemia results from cerebrovascular occlusion, which leads to neuronal cell death and eventually causes neurological impairments. Dexmedetomidine is a potent and highly selective α2-adrenoreceptor agonist with actions such as sedation, anxiolysis, analgesia and anesthetic-sparing effects. We investigated the effect of dexmedetomidine on apoptosis in the hippocampus after transient global ischemia in gerbils. Transient global ischemia was induced by ligation of both common carotid arteries. Dexmedetomidine was administrated intraperitoneally at three respective doses (0.1, 1 and 10 µg/kg) once per day for 14 consecutive days beginning a day after surgery. Short-term memory was assessed by use of a step-down avoidance task. Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling assay, immunohistochemistry for caspase-3, and western blot analysis of Bcl-2-associated X protein, B-cell lymphoma 2, Bid, cytochrome c, apoptotic protease activating factor-1 and caspase-9 in the hippocampus. Induction of global ischemia deteriorated short-term memory by enhancing the expression of apoptosis-related molecules in the hippocampus. Treatment with dexmedetomidine suppressed the expression of apoptosis-related molecules under ischemic conditions, resulting in short-term memory improvement. Under normal conditions, dexmedetomidine exerted no significant effect on apoptosis in the hippocampus. The present results suggest that the α2-adrenoceptor agonist dexmedetomidine may be a useful therapeutic agent for the treatment of ischemic brain diseases. PMID:28123477
Wallhäusser-Franke, E; Mahlke, C; Oliva, R; Braun, S; Wenz, G; Langner, G
Subjective tinnitus is a phantom sound sensation that does not result from acoustic stimulation and is audible to the affected subject only. Tinnitus-like sensations in animals can be evoked by procedures that also cause tinnitus in humans. In gerbils, we investigated brain activation after systemic application of sodium salicylate or exposure to loud noise, both known to be reliable tinnitus-inductors. Brains were screened for neurons containing the c-fos protein. After salicylate injections, auditory cortex was the only auditory area with consistently increased numbers of immunoreactive neurons compared to controls. Exposure to impulse noise led to prolonged c-fos expression in auditory cortex and dorsal cochlear nucleus. After both manipulations c-fos expression was increased in the amygdala, in thalamic midline, and intralaminar areas, in frontal cortex, as well as in hypothalamic and brainstem regions involved in behavioral and physiological defensive reactions. Activation of these non-auditory areas was attributed to acute stress, to aversive-affective components and autonomous reactions associated with the treatments and a resulting tinnitus. The present findings are in accordance with former results that provided evidence for suppressed activation in auditory midbrain but enhanced activation of the auditory cortex after injecting high doses of salicylate. In addition, our present results provide evidence that acute stress coinciding with a disruption of hearing may evoke activation of the auditory cortex. We interpret these results in favor of our model of central tinnitus generation.
Chatterjee, Aparajita; Bandini, Giulia; Motari, Edwin; Samuelson, John
Enteric protozoan parasites, which are spread by the fecal-oral route, are important causes of diarrhea (Giardia duodenalis) and amebic dysentery (Entamoeba histolytica). Cyst walls of Giardia and Entamoeba have a single layer composed of fibrils of β-1,3-linked GalNAc and β-1,4-linked GlcNAc (chitin), respectively. The goal here was to determine whether hand sanitizers that contain ethanol or isopropanol as the active microbicide might reduce transmission of these parasites. We found that treatment with these alcohols with or without drying in a rotary evaporator (to model rapid evaporation of sanitizers on hands) kills 85 to 100% of cysts of G. duodenalis and 90 to 100% of cysts of Entamoeba invadens (a nonpathogenic model for E. histolytica), as shown by nuclear labeling with propidium iodide and failure to excyst in vitro. Alcohols with or without drying collapsed the cyst walls of Giardia but did not collapse the cyst walls of Entamoeba. To validate the in vitro results, we showed that treatment with alcohols eliminated oral infection of gerbils by 1,000 G. duodenalis cysts, while a commercial hand sanitizer (Purell) killed E. invadens cysts that were directly applied to the hands. These results suggest that expanded use of alcohol-based hand sanitizers might reduce the transmission of Giardia and Entamoeba.
Lehmann, Konrad; Rodriguez, Enrique Garea; Kratz, Oliver; Moll, Gunther H; Dawirs, Ralph R; Teuchert-Noodt, Gertraud
Adrenal steroid hormones and neuronal growth factors are two interacting systemic factors that mediate the environment's influence on the brain's structure and function. In order to further elucidate their role and relationship in the effects of early stressful experience and isolated rearing (IR), this study measured blood corticosterone titres and relative adrenal weights and assessed nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) concentrations in brain regions of both hemispheres of young adult Mongolian gerbils injected on postnatal day 14 with a single high dose of methamphetamine (MA) or saline and raised after weaning either in an enriched or an impoverished environment. Irrespective of MA challenge, IR decreased corticosterone titres to about half, but increased relative adrenal weights. BDNF concentrations were decreased by IR in saline-injected animals in the left prefrontal and parietal cortices and right entorhinal and hippocampal cortices, and in the subcortical regions of both hemispheres. NGF concentrations were unaltered by IR in saline-injected animals, but increased in MA challenged animals in the entorhinal/hippocampal cortices and subcortical areas of both hemispheres. MA application induced shifts of the lateral asymmetry in NGF contents in prefrontal and entorhinal cortices. The results suggest that an early pharmacological traumatization can set a switch for further brain development, and that growth factor concentrations might possibly be influenced by peripheral stress hormones.
Biancardi, Manoel F; Perez, Ana PS; Caires, Cássia RS; Falleiros, Luiz R; Góes, Rejane M; Vilamaior, Patrícia SL; Freitas, Diógenes R; Santos, Fernanda CA; Taboga, Sebastião R
The prostate is an accessory sex gland that develops under precise androgenic control. It is known that hormonal imbalance may disrupt its development predisposing this gland to develop diseases during aging. Although the hypothesis regarding earlier origins of prostate diseases was proposed many years ago, the mechanisms underlying this complex phenomenon are poorly understood. Therefore, the aim of this study was to evaluate the prostates of old male gerbils exposed to testosterone during intrauterine and postnatal life using morphological, biometrical, stereological, Kariometric, immunohistochemical, and immunofluorescence analyses. Our findings demonstrate that prenatal and pubertal exposure to testosterone increases the susceptibility to the development of prostate diseases during aging. The presence of a more proliferative gland associated with foci of adenomatous hyperplasia in animals exposed to testosterone during the prenatal and pubertal phase show that the utero life and the pubertal period are important phases for prostatic morphophysiology establishment, which is a determinant for the health of the gland during aging. Therefore, these findings reinforce the idea that prostate disease may result from hormonal disruptions in early events during prostate development, which imprint permanently on the gland predisposing it to develop lesions in later stages of life. PMID:26780870
Chen, Bai Hui; Park, Joon Ha; Ahn, Ji Hyeon; Cho, Jeong Hwi; Kim, In Hye; Lee, Jae Chul; Won, Moo-Ho; Lee, Choong-Hyun; Hwang, In Koo; Kim, Jong-Dai; Kang, Il Jun; Cho, Jun Hwi; Shin, Bich Na; Kim, Yang Hee; Lee, Yun Lyul; Park, Seung Min
Quercetin (QE; 3,5,7,3′,4′-pentahydroxyflavone), a well-known flavonoid, has been shown to prevent against neurodegenerative disorders and ischemic insults. However, few studies are reported regarding the neuroprotective mechanisms of QE after ischemic insults. Therefore, in this study, we investigated the effects of QE on ischemic injury and the expression of antioxidant enzymes in the hippocampal CA1 region of gerbils subjected to 5 minutes of transient cerebral ischemia. QE was pre-treated once daily for 15 days before ischemia. Pretreatment with QE protected hippocampal CA1 pyramidal neurons from ischemic injury, which was confirmed by neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, pretreatment with QE significantly increased the expression levels of endogenous antioxidant enzymes Cu/Zn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase in the hippocampal CA1 pyramidal neurons of animals with ischemic injury. These findings demonstrate that pretreated QE displayed strong neuroprotective effects against transient cerebral ischemia by increasing the expression of antioxidant enzymes.
Biancardi, Manoel F; Perez, Ana Ps; Caires, Cássia Rs; Falleiros, Luiz R; Góes, Rejane M; Vilamaior, Patrícia Sl; Freitas, Diógenes R; Santos, Fernanda Ca; Taboga, Sebastião R
The prostate is an accessory sex gland that develops under precise androgenic control. It is known that hormonal imbalance may disrupt its development predisposing this gland to develop diseases during aging. Although the hypothesis regarding earlier origins of prostate diseases was proposed many years ago, the mechanisms underlying this complex phenomenon are poorly understood. Therefore, the aim of this study was to evaluate the prostates of old male gerbils exposed to testosterone during intrauterine and postnatal life using morphological, biometrical, stereological, Kariometric, immunohistochemical, and immunofluorescence analyses. Our findings demonstrate that prenatal and pubertal exposure to testosterone increases the susceptibility to the development of prostate diseases during aging. The presence of a more proliferative gland associated with foci of adenomatous hyperplasia in animals exposed to testosterone during the prenatal and pubertal phase show that the utero life and the pubertal period are important phases for prostatic morphophysiology establishment, which is a determinant for the health of the gland during aging. Therefore, these findings reinforce the idea that prostate disease may result from hormonal disruptions in early events during prostate development, which imprint permanently on the gland predisposing it to develop lesions in later stages of life.
Park, Chan Woo; Lee, Jae-Chul; Ahn, Ji Hyeon; Lee, Dae Hwan; Cho, Geum-Sil; Yan, Bing Chun; Park, Joon Ha; Kim, In Hye; Lee, Hui Young; Won, Moo-Ho; Cho, Jun Hwi
The extent of neuronal damage/death in some brain regions is highly correlated to duration time of transient ischemia. In the present study, we carried out neuronal degeneration/death and glial changes in the septum 4 days after 5, 10, 15, and 20 min of transient cerebral ischemia using gerbils. To examine neuronal damage, Fluoro-Jade B (F-J B, a marker for neuronal degeneration) histofluorescence staining was used. F-J B positive ((+)) cells were detected in the septo-hippocampal nucleus (SHN) of the septum only in the 20 min ischemia-group; the mean number of F-J B(+) neurons was 14.9 ± 2.5/400 μm(2) in a section. Gliosis of astrocytes and microglia was examined using anti-glial fibrillary acidic protein (GFAP) and anti-ionized calcium-binding adapter molecule 1 (Iba-1), respectively. In all the ischemia-groups, GFAP- and Iba-1-immunoreactive astrocytes and microglia, respectively, were increased in number, and apparently tended to be increased in their immunoreactivity. Especially, in the 20 min ischemia-group, the number and immunoreactivity of Iba-immunoreactive microglia was highest and strongest in the ischemic SHN 4 days after ischemia-reperfusion. In brief, our findings showed that neuronal damage/death in the SHN occurred and gliosis was apparently increased in the 20 min ischemia-group at 4 days after ischemia-reperfusion.
Lin, Jing-Ying; Cheng, Fu-Chou; Chung, Shu-Ying; Lin, Ming-Cheng
Cell death after cerebral ischemia is mediated by the accumulation of excitatory amino acids, calcium influx into cells and the generation of free radicals. The aim of this study was to evaluate changes in energy-related metabolites in the striatum of gerbils subjected to focal cerebral ischemia after pretreatment with Ginkgo biloba extract (EGb761), a well-known antioxidant, and FK506, a calcium-dependent phosphatase calcineurin inhibitor. Ischemia was induced by occlusion of the right common carotid artery and the right middle cerebral artery for 60 min. A microdialysis probe was inserted into the right striatum to monitor extracellular glucose, lactate and pyruvate levels. This study showed decreases in glucose (10% of the baseline), pyruvate (20% of the baseline) and lactate (60% of the baseline), and a 5-fold increase in the lactate to pyruvate ratio during ischemia in the control group. Both EGb761 treatment and the combination (EGb761 and FK506) therapy significantly preserved glucose (50% of the baseline) and pyruvate (60% of the baseline) levels during ischemia. The marked increase in the lactate to pyruvate ratio was not observed in the combination group. These results suggest that preservation of cellular energy metabolism during cerebral ischemia and after restoration with reperfusion may contribute to the neuroprotective effects of EGb761 and FK506.
Liu, D S; Achouche, J; Wu, A H; Trotier, D; Tran Ba Huy, P
Using primary cultures of marginal cells of stria vascularis from guinea pig and gerbil, ionic channels located on the luminal membrane were investigated by means of patch clamp technique. Recordings were performed in cell-attached and inside-out configurations. In cell-attached configuration, single channel activity was identified with a conductance of about 25 pS. I-V curve was linear. The probability of opening was increased upon depolarization. Up to 7 channels could be present in the same patch, indicating a rather high density. In inside-out configuration, the reversal potential was 0 mV, suggesting a non-specific cationic channel. These luminal non-specific cationic channels would allow the passive K+ efflux and Na+ influx across the apical membrane of marginal cells. This finding is consistent with the "one-pump" model of strial activity. The present study suggests that culture of strial marginal cells may be a suitable model for in-depth investigation of endolymph physiology.
Wang, Qun; Sun, Albert Y; Pardeike, Jana; Müller, Rainer H; Simonyi, Agnes; Sun, Grace Y
The group IIA secretory phospholipase A2 (sPLA(2)-IIA) has been studied extensively because of its involvement in inflammatory processes. Up-regulation of this enzyme has been shown in a number of neurodegenerative diseases including cerebral ischemia and Alzheimer's disease. PX-18 is a selective sPLA(2) inhibitor effective in reducing tissue damage resulting from myocardial infarction. However, its use as a neuroprotective agent has been hampered due to its low solubility. In this study, we test the possible neuroprotective effects of PX-18 formulated as a suspension of nanocrystals. Transient global cerebral ischemia was induced in gerbils by occlusion of both common carotid arteries for 5 min. Four days after ischemia/reperfusion (I/R), extensive delayed neuronal death, DNA damage, and increases in reactive astrocytes and microglial cells were observed in the hippocampal CA1 region. PX-18 nanocrystals (30 and 60 mg/kg body wt) and vehicle controls were injected i.p. immediately after I/R. PX-18 nanocrystal injection significantly reduced delayed neuronal death, DNA damage, as well as glial cell activation. These findings demonstrated the effective neuroprotection of PX-18 in the form of nanocrystal against I/R-induced neuronal damage. The results also suggest that nanocrystals hold promise as an effective strategy for the delivery of compounds with poor solubility that would otherwise be precluded from preclinical development.
Lee, Jae-Chul; Ahn, Ji Hyeon; Kim, In Hye; Park, Joon Ha; Yan, Bing Chun; Cho, Geum-Sil; Ohk, Taek Geun; Park, Chan Woo; Cho, Jun Hwi; Kim, Young-Myeong; Lee, Hui Young; Won, Moo-Ho
Chemokines and their receptors are important players in organism homeostasis, development and immune response to inflammatory stimuli. In the present study, we examined effects of ischemia-reperfusion injury on the immunoreactivity and protein levels of chemokine C-C motif receptor 7 (CCR7) in the gerbil hippocampus (CA1-3 regions) after 5 min of transient global cerebral ischemia. CCR7 immunoreactivity was dramatically changed in the pyramidal neurons of the CA1, not CA2/3, region after ischemia-reperfusion. The immunoreactivity was increased after ischemia-reperfusion, and it was barely found from 5 days post-ischemia. In addition, CCR7 immunoreactivity was newly expressed in astrocytes, not microglia, in the ischemic CA1 region from 5 days post-ischemia. However, we did not observe this finding in the ischemic CA2/3 region. Furthermore, CCR7 protein levels in the ischemic CA1 region were changed like the change pattern of its immunoreactivity. These results indicate that both CCR7 immunoreactivity and protein levels are distinctively altered only in the CA1 region after transient cerebral ischemia and that the changes in CCR7 expression may be related to the ischemia-induced delayed neuronal death.
Li, Hua; Park, Joon Ha; Yan, Bingchun; Yoo, Ki-Yeon; Lee, Choong Hyun; Choi, Jung Hoon; Hwang, In Koo; Won, Moo-Ho
The extract of Alpinia katsumadai, a member of the family Zingiberaceae, shows anti-inflammatory effects and antioxidant activity. We observed the neuroprotective effects of the extract from Alpinia katsumadai seed (EAKS) against ischemic damage in gerbils administered oral EAKS (25, and 50 mg/kg) once a day for 7 days before transient cerebral ischemia. In the 50 mg/kg EAKS-treated ischemia group, about 67% of neurons in the hippocampal CA1 region (CA1) survived after ischemia/reperfusion (I/R) based on cresyl violet staining. We observed that EAKS treatment significantly maintained brain-derived neurotrophic factor (BDNF) immunoreactivity in the ischemic CA1 region after I/R. In addition, protein levels of BDNF in the 50 mg/kg EAKS-treated ischemia group were much higher than those in the vehicle-treated ischemia group after I/R. These findings indicate that repeated supplementation of EAKS protects neurons from ischemic damage, such that BDNF is distinctively maintained in ischemic areas.
Hwang, In Koo; Hua, Li; Yoo, Ki-Yeon; Kim, Dae Won; Kang, Tae-Cheon; Choi, Soo Young; Won, Moo Ho; Kim, Do-Hoon
In the present study, we observed chronological changes of antioxidant-like protein 1 (AOP-1) in the gerbil hippocampal CA1 region after 5 min of transient forebrain ischemia using immunohistochemistry and western blot. AOP-1 was significantly altered in the CA1 region after transient ischemia. In the sham-operated group, AOP-1 immunoreactivity was detected in pyramidal and non-pyramidal cells of the CA1 region. At 30 min after ischemic insult, AOP-1 immunoreactivity and protein level was decreased in the CA1 region. At 12 h after ischemic insult, AOP-1 immunoreactivity and protein level was highest in this region. At this time, after ischemia, AOP-1 immunoreactivity in non-pyramidal cells was high compared to the sham-operated group. Based on double immunofluorescence study, AOP-1-immunoreactive neurons were identified as GABAergic, which were stained with GAD or parvalbumin. Thereafter, AOP-1 immunoreactivity and protein levels were decreased time-dependently. From 4 days after ischemic insult, AOP 1 immunoreactivity was generally expressed in astrocytes. Five days after ischemic insult, AOP-1 immunoreactivity and protein level was increased again to 1.4 folds compared to that of the sham-operated group. In brief, AOP-1 immunoreactivity was increased in GABAergic non-pyramidal cells in the hippocampal CA1 region at early time after ischemic insult and was expressed in astrocytes at late time after ischemia. This result suggests that AOP-1 may be important role in homeostasis of GABAergic neurons because these neurons are resistant to ischemic damage.
Kim, Dong Won; Lee, Jae-Chul; Cho, Jeong-Hwi; Park, Joon Ha; Ahn, Ji Hyeon; Chen, Bai Hui; Shin, Bich-Na; Tae, Hyun-Jin; Seo, Jeong Yeol; Cho, Jun Hwi; Kang, Il Jun; Hong, Seongkweon; Kim, Young-Myeong; Won, Moo-Ho; Kim, In Hye
Ischemic preconditioning (IPC) induced by sublethal transient cerebral ischemia could reduce neuronal damage/death following a subsequent lethal transient cerebral ischemia. We, in this study, compared expressions of interleukin (IL)-2 and tumor necrosis factor (TNF)-α as pro-inflammatory cytokines, and IL-4 and IL-13 as anti-inflammatory cytokines in the gerbil hippocampal CA1 region between animals with lethal ischemia and ones with IPC followed by lethal ischemia. In the animals with lethal ischemia, pyramidal neurons in the stratum pyramidale (SP) of the hippocampal CA1 region were dead at 5 days post-ischemia; however, IPC protected the CA1 pyramidal neurons from lethal ischemic injury. Expressions of all cytokines were significantly decreased in the SP after lethal ischemia and hardly detected in the SP at 5 days post-ischemia because the CA1 pyramidal neurons were dead. IPC increased expressions of anti-inflammatory cytokines (IL-4 and IL-13) in the stratum pyramidale of the CA1 region following no lethal ischemia (sham-operation), and the increased expressions of IL-4 and IL-13 by IPC were continuously maintained is the SP of the CA1 region after lethal ischemia. However, pro-inflammatory cytokines (IL-2 and TNF-α) in the SP of the CA1 region were similar those in the sham-operated animals with IPC, and the IL-4 and IL-13 expressions in the SP were maintained after lethal ischemia. In conclusion, this study shows that anti-inflammatory cytokines significantly increased and longer maintained by IPC and this might be closely associated with neuroprotection after lethal transient cerebral ischemia.
Gouaref, Inès; Detaille, Dominique; Wiernsperger, Nicolas; Khan, Naim Akhtar; Leverve, Xavier; Koceir, Elhadj-Ahmed
Introduction While metformin (MET) is the most widely prescribed antidiabetic drug worldwide, its beneficial effects in Psammomys obesus (P. obesus), a rodent model that mimics most of the metabolic features of human diabetes, have not been explored thoroughly. Here, we sought to investigate whether MET might improve insulin sensitivity, glucose homeostasis, lipid profile as well as cellular redox and energy balance in P. obesus maintained on a high energy diet (HED). Materials and methods P. obesus gerbils were randomly assigned to receive either a natural diet (ND) consisting of halophytic plants (control group) or a HED (diabetic group) for a period of 24 weeks. MET (50 mg/kg per os) was administered in both animal groups after 12 weeks of feeding, i.e., the time required for the manifestation of insulin resistance in P. obesus fed a HED. Parallel in vitro experiments were conducted on isolated hepatocytes that were shortly incubated (30 min) with MET and energetic substrates (lactate + pyruvate or alanine, in the presence of octanoate). Results In vivo, MET lowered glycemia, glycosylated haemoglobin, circulating insulin and fatty acid levels in diabetic P. obesus. It also largely reversed HED-induced hepatic lipid alterations. In vitro, MET increased glycolysis but decreased both gluconeogenesis and ketogenesis in the presence of glucogenic precursors and medium-chain fatty acid. Importantly, these changes were associated with an increase in cytosolic and mitochondrial redox states along with a decline in respiration capacity. Conclusions MET prevents the progression of insulin resistance in diabetes-prone P. obesus, possibly through a tight control of gluconeogenesis and fatty acid β-oxidation depending upon mitochondrial function. While the latter is increasingly becoming a therapeutic issue in diabetes, the gut microbiota is another promising target that would need to be considered as well. PMID:28222147
Zampini, Valeria; Johnson, Stuart L.; Franz, Christoph; Knipper, Marlies; Holley, Matthew C.; Magistretti, Jacopo; Russo, Giancarlo; Marcotti, Walter; Masetto, Sergio
Hearing relies on faithful signal transmission by cochlear inner hair cells (IHCs) onto auditory fibres over a wide frequency and intensity range. Exocytosis at IHC ribbon synapses is triggered by Ca2+ inflow through CaV1.3 (L-type) Ca2+ channels. We investigated the macroscopic (whole-cell) and elementary (cell-attached) properties of Ca2+ currents in IHCs positioned at the middle turn (frequency ∼2 kHz) of the adult gerbil cochlea, which is their most sensitive hearing region. Using near physiological recordings conditions (body temperature and a Na+ based extracellular solution), we found that the macroscopic Ca2+ current activates and deactivates very rapidly (time constant below 1 ms) and inactivates slowly and only partially. Single-channel recordings showed an elementary conductance of 15 pS, a sub-ms latency to first opening, and a very low steady-state open probability (Po: 0.024 in response to 500-ms depolarizing steps at ∼−18 mV). The value of Po was significantly larger (0.06) in the first 40 ms of membrane depolarization, which corresponds to the time when most Ca2+ channel openings occurred clustered in bursts (mean burst duration: 19 ms). Both the Po and the mean burst duration were smaller than those previously reported in high-frequency basal IHCs. Finally, we found that middle turn IHCs are likely to express about 4 times more Ca2+ channels per ribbon than basal cells. We propose that middle-turn IHCs finely-tune CaV1.3 Ca2+ channel gating in order to provide reliable information upon timing and intensity of lower-frequency sounds. PMID:25409445
Ohk, Taek Geun; Yoo, Ki-Yeon; Park, Seung Min; Shin, Bich Na; Kim, In Hye; Park, Joon Ha; Ahn, Hee Cheol; Lee, Young Joo; Kim, Myong Jo; Kim, Tae Young; Won, Moo-Ho; Cho, Jun Hwi
Ischemic damage occurs well in vulnerable regions of the brain, including the hippocampus and striatum. In the present study, we examined neuronal damage/death and glial changes in the striatum 4 days after 5, 10, 15 and 20 min of transient cerebral ischemia using the gerbil. Spontaneous motor activity was increased with the duration time of ischemia-reperfusion (I-R). To examine neuronal damage, we used Fluoro-Jade B (F-J B, a marker for neuronal degeneration) histofluorescence staining. F-J B positive cells were detected only in the 20 min ischemia-group, not in the other groups. In addition, we examined gliosis of astrocytes and microglia using anti-glial fibrillary acidic protein (GFAP) and anti- ionized calcium-binding adapter molecule 1 (Iba-1), respectively. In the 5 min ischemia-group, GFAP-immunoreactive astrocytes were distinctively increased in number, and the immunoreactivity was stronger than that in the sham-group. In the 10, 15 and 20 min ischemia-groups, GFAP-immunoreactivity was more increased with the duration of I-R. On the other hand, the immunoreactivity and the number of Iba-1-immunoreactive microglia were distinctively increased in the 5 and 10 min ischemia-groups. In the 15 min ischemia-group, cell bodies of microglia were largest, and the immunoreactivity was highest; however, in the 20 min ischemia-group, the immunoreactivity was low compared to the 15 min ischemia-group. The results of western blotting for GFAP and Iba-1 were similar to the immunohistochemical data. In brief, these findings showed that neuronal death could be detected only in the 20 min ischemia-group 4 days after I-R, and the change pattern of astrocytes and microglia were apparently different according to the duration time of I-R.
Lee, Hui Young; Tae, Hyun-Jin; Cho, Geum-Sil; Kim, In Hye; Cho, Jeong Hwi; Park, Joon Ha; Ahn, Ji Hyeon; Chen, Bai Hui; Shin, Bich-Na; Won, Moo-Ho; Park, Chan Woo; Cho, Jun Hwi; Seo, Jeong Yeol; Lee, Jae-Chul
Objective(s): In the present study, we investigated the effect of ischemic preconditioning (IPC) on c-myb immunoreactivity as well as neuronal damage/death after a subsequent lethal transient ischemia in gerbils. Materials and Methods: IPC was subjected to a 2 min sublethal ischemia and a lethal transient ischemia was given 5 min transient ischemia. The animals in all of the groups were given recovery times of 1 day, 2 days and 5 days and we examined change in c-myb immunoreactivity as well as neuronal damage/death in the hippocampus induced by a lethal transient ischemia. Results: A lethal transient ischemia induced a significant loss of cells in the stratum pyramidale (SP) of the hippocampal CA1 region at 5 days post-ischemia, and this insult showed that c-myb immunoreactivity in cells of the SP of the CA1 region was significantly decreased at 2 days post-ischemia and disappeared at 5 days post-ischemia. However, IPC effectively prevented the neuronal loss in the SP and showed that c-myb immunoreactivity was constitutively maintained in the SP after a lethal transient ischemia. Conclusion: Our results show that a lethal transient ischemia significantly decreased c-myb immunoreactivity in the SP of the CA1 region and that IPC well preserved c-myb immunoreactivity in the SP of the CA1 region. We suggest that the maintenance of c-myb might be related with IPC-mediated neuroprotection after a lethal ischemic insult. PMID:27482343
Wang, Yuan; Sakano, Hitomi; Beebe, Karisa; Brown, Maile R; de Laat, Rian; Bothwell, Mark; Kulesza, Randy J; Rubel, Edwin W
Neuronal dendrites are structurally and functionally dynamic in response to changes in afferent activity. The fragile X mental retardation protein (FMRP) is an mRNA binding protein that regulates activity-dependent protein synthesis and morphological dynamics of dendrites. Loss and abnormal expression of FMRP occur in fragile X syndrome (FXS) and some forms of autism spectrum disorders. To provide further understanding of how FMRP signaling regulates dendritic dynamics, we examined dendritic expression and localization of FMRP in the reptilian and avian nucleus laminaris (NL) and its mammalian analogue, the medial superior olive (MSO), in rodents and humans. NL/MSO neurons are specialized for temporal processing of low-frequency sounds for binaural hearing, which is impaired in FXS. Protein BLAST analyses first demonstrate that the FMRP amino acid sequences in the alligator and chicken are highly similar to human FMRP with identical mRNA-binding and phosphorylation sites, suggesting that FMRP functions similarly across vertebrates. Immunocytochemistry further reveals that NL/MSO neurons have very high levels of dendritic FMRP in low-frequency hearing vertebrates including alligator, chicken, gerbil, and human. Remarkably, dendritic FMRP in NL/MSO neurons often accumulates at branch points and enlarged distal tips, loci known to be critical for branch-specific dendritic arbor dynamics. These observations support an important role for FMRP in regulating dendritic properties of binaural neurons that are essential for low-frequency sound localization and auditory scene segregation, and support the relevance of studying this regulation in nonhuman vertebrates that use low frequencies in order to further understand human auditory processing disorders.
Scott, Luisa L; Hage, Travis A; Golding, Nace L
Principal neurons of the medial superior olive (MSO) convey azimuthal sound localization cues through modulation of their rate of action potential firing. Previous intracellular studies in vitro have shown that action potentials appear highly attenuated at the soma of MSO neurons, potentially reflecting specialized action potential initiation and/or a physically distant site of generation. To examine this more directly, we made dual patch-clamp recordings from MSO principal neurons in gerbil brainstem slices. Using somatic and dendritic whole-cell recordings, we show that graded action potentials at the soma are highly sensitive to the rate of rise of excitation and undergo strong attenuation in their backpropagation into the dendrites (length constant, 76 microm), particularly during strong dendritic excitation. Using paired somatic whole-cell and axonal loose-patch recordings, we show that action potentials recorded in the axon at distances > 25 microm are all-or-none, and uniform in amplitude even when action potentials appear graded at the soma. This proximal zone corresponded to the start of myelination in the axon, as assessed with immunocytochemical staining for myelin basic protein in single-labelled neurons. Finally, the axon was capable of sustaining remarkably high firing rates, with perfect entrainment occurring at frequencies of up to 1 kHz. Together, our findings show that action potential signalling in MSO principal neurons is highly secure, but shows a restricted invasion of the somatodendritic compartment of the cell. This restriction may be important for minimizing distortions in synaptic integration during the high frequencies of synaptic input encountered in the MSO.
Zampini, Valeria; Johnson, Stuart L; Franz, Christoph; Knipper, Marlies; Holley, Matthew C; Magistretti, Jacopo; Russo, Giancarlo; Marcotti, Walter; Masetto, Sergio
Hearing relies on faithful signal transmission by cochlear inner hair cells (IHCs) onto auditory fibres over a wide frequency and intensity range. Exocytosis at IHC ribbon synapses is triggered by Ca(2+) inflow through Ca(V)1.3 (L-type) Ca(2+) channels. We investigated the macroscopic (whole-cell) and elementary (cell-attached) properties of Ca(2+) currents in IHCs positioned at the middle turn (frequency ∼ 2 kHz) of the adult gerbil cochlea, which is their most sensitive hearing region. Using near physiological recordings conditions (body temperature and a Na(+) based extracellular solution), we found that the macroscopic Ca(2+) current activates and deactivates very rapidly (time constant below 1 ms) and inactivates slowly and only partially. Single-channel recordings showed an elementary conductance of 15 pS, a sub-ms latency to first opening, and a very low steady-state open probability (Po: 0.024 in response to 500-ms depolarizing steps at ∼-18 mV). The value of Po was significantly larger (0.06) in the first 40 ms of membrane depolarization, which corresponds to the time when most Ca(2+) channel openings occurred clustered in bursts (mean burst duration: 19 ms). Both the Po and the mean burst duration were smaller than those previously reported in high-frequency basal IHCs. Finally, we found that middle turn IHCs are likely to express about 4 times more Ca(2+) channels per ribbon than basal cells. We propose that middle-turn IHCs finely-tune Ca(V)1.3 Ca(2+) channel gating in order to provide reliable information upon timing and intensity of lower-frequency sounds.
Porres, Christian P; Meyer, Elisabeth M M; Grothe, Benedikt; Felmy, Felix
Neurons in the dorsal nucleus of the lateral lemniscus (DNLL) receive excitatory and inhibitory inputs from the superior olivary complex (SOC) and convey GABAergic inhibition to the contralateral DNLL and the inferior colliculi. Unlike the fast glycinergic inhibition in the SOC, this GABAergic inhibition outlasts auditory stimulation by tens of milliseconds. Two mechanisms have been postulated to explain this persistent inhibition. One, an "integration-based" mechanism, suggests that postsynaptic excitatory integration in DNLL neurons generates prolonged activity, and the other favors the synaptic time course of the DNLL output itself. The feasibility of the integration-based mechanism was tested in vitro in DNLL neurons of Mongolian gerbils by quantifying the cellular excitability and synaptic input-output functions (IO-Fs). All neurons were sustained firing and generated a near monotonic IO-F on current injections. From synaptic stimulations, we estimate that activation of approximately five fibers, each on average liberating ∼18 vesicles, is sufficient to trigger a single postsynaptic action potential. A strong single pulse of afferent fiber stimulation triggered multiple postsynaptic action potentials. The steepness of the synaptic IO-F was dependent on the synaptic NMDA component. The synaptic NMDA receptor current defines the slope of the synaptic IO-F by enhancing the temporal and spatial EPSP summation. Blocking this NMDA-dependent amplification during postsynaptic integration of train stimulations resulted into a ∼20% reduction of the decay time course of the GABAergic inhibition. Thus, our data show that the NMDA-dependent amplification of the postsynaptic activity contributes to the GABAergic persistent inhibition generated by DNLL neurons.
Shafrir, Eleazar; Ziv, Ehud; Kalman, Rony
The dietary effects of hyperglycemia increasingly result in type 2 diabetes in humans. Two species, the spiny mice (Acomys cahirinus) and the desert gerbil (Psammomys obesus), which have different metabolic responses to such effects, are discussed. Spiny mice exemplify a pathway that leads to diabetes without marked insulin resistance due to low supply of insulin on abundant nutrition, possibly characteristic of a desert animal. They respond with obesity and glucose intolerance, beta-cell hyperplasia, and hypertrophy on a standard rodent diet supplemented with fat-rich seeds. The accompanying hyperglycemia and hyperinsulinemia are mild and intermittent but after a few months, the enlarged pancreatic islets suddenly collapse, resulting in loss of insulin and ketosis. Glucose and other secretagogues produce only limited insulin release in vivo and in vitro, pointing to the inherent disability of the beta-cells to respond with proper insulin secretion despite their ample insulin content. On a 50% sucrose diet there is marked lipogenesis with hyperlipidemia without obesity or diabetes, although beta-cell hypertrophy is evident. P.obesus is characterized by muscle insulin resistance and the inability of insulin to activate the insulin signaling on a high-energy (HE) diet. Insulin resistance imposes a vicious cycle of Hyperglycemia and compensatory hyperinsulinemia, leading to beta-cell failure and increased secretion of proinsulin. Ultrastructural studies reveal gradual disappearance of beta-cell glucokinase, GLUT 2 transporter, and insulin, followed by apoptosis of beta-cells. Studies using the non-insulin-resistant HE diet-fed animals maintained as a control group are discussed. The insulin resistance that is evident to date in the normoglycemic state on a low-energy diet indicates sparing of glucose fuel in muscles of a desert-adapted animal for the benefit of glucose obligatory tissues. Also discussed are the effect of Psammomys age on the disabetogenicity of the HE
Lee, Jae-Chul; Cho, Jeong-Hwi; Kim, In Hye; Ahn, Ji Hyeon; Park, Joon Ha; Cho, Geum-Sil; Chen, Bai Hui; Shin, Bich Na; Tae, Hyun-Jin; Park, Seung Min; Ahn, Ji Yun; Kim, Dong Won; Cho, Jun Hwi; Bae, Eun Joo; Yong, Jun-Hwan; Kim, Young-Myeong; Won, Moo-Ho; Lee, Yun Lyul
The participation of Na(+)/H(+) exchanger (NHE) in neuronal damage/death in the hippocampal CA1 region (CA1) induced by transient forebrain ischemia has not been well established, although acidosis may be involved in neuronal damage/death. In the present study, we examined the effect of ischemic preconditioning (IPC) on NHE1 immunoreactivity following a 5min of transient forebrain ischemia in gerbils. The animals used in the study were randomly assigned to four groups (sham-operated-group, ischemia-operated-group, IPC plus (+) sham-operated-group and IPC+ischemia-operated-group). IPC was induced by subjecting animals to 2min of ischemia followed by 1day of recovery. A significant neuronal loss was found in the stratum pyramidale (SP) of the CA1, not the CA2/3, of the ischemia-operated-group at 5days post-ischemia. However, in the IPC+ischemia-operated-group, neurons in the SP of the CA1 were well protected. NHE1 immunoreactivity was not detected in any regions of the CA1-3 of the sham- and IPC+sham-operated-groups. However, the immunoreactivity was apparently expressed in the SP of the CA1-3 after ischemia, and the NHE1immunoreactivity was very weak 5days after ischemia; however, at this point in time, strong NHE1immunoreactivity was found in astrocytes in the CA1. In the CA2/3, NHE1immunoreactivity was slightly changed, although NHE1immunoreactivity was expressed in the SP. In the IPC+ischemia-operated-groups, NHE1 immunoreactivity was also expressed in the SP of the CA1-3; however, the immunoreactivity was more slightly changed than that in the ischemia-operated-groups. In brief, our findings show that IPC dramatically protected CA1 pyramidal neurons and strongly inhibited NHE1 expression in the SP of the CA1 after ischemia-reperfusion. These findings suggest that the inhibition of NHE1 expression may be necessary for neuronal survival from transient ischemic damage.
Reimann, Katrin; Krishnamoorthy, Gayathri; Wangemann, Philine
Cochlear blood flow regulation is important to prevent hearing loss caused by ischemia and oxidative stress. Cochlear blood supply is provided by the spiral modiolar artery (SMA). The myogenic tone of the SMA is enhanced by the nitric oxide synthase (NOS) blocker L-N(G)-nitro-arginine (LNNA) in males, but not in females. Here, we investigated whether this gender difference is based on differences in the cytosolic Ca(2+) concentration and/or the Ca(2+) sensitivity of the myofilaments. Vascular diameter, myogenic tone, cytosolic Ca(2+), and Ca(2+) sensitivity were evaluated in pressurized SMA segments isolated from male and female gerbils using laser-scanning microscopy and microfluorometry. The gender difference of the LNNA-induced tone was compared, in the same vessel segments, to tone induced by 150 mM K(+) and endothelin-1, neither of which showed an apparent gender-difference. Interestingly, LNNA-induced tone in male SMAs was observed in protocols that included changes in intramural pressure, but not when the intramural pressure was held constant. LNNA in male SMAs did not increase the global Ca(2+) concentration in smooth muscle cells but increased the Ca(2+) sensitivity. This increase in the Ca(2+) sensitivity was abolished in the presence of the guanylyl cyclase inhibitor ODQ or by extrinsic application of either the nitric oxide (NO)-donor DEA-NONOate or the cGMP analog 8-pCPT-cGMP. The rho-kinase blocker Y27632 decreased the basal Ca(2+) sensitivity and abolished the LNNA-induced increase in Ca(2+) sensitivity in male SMAs. Neither LNNA nor Y27632 changed the Ca(2+) sensitivity in female SMAs. The data suggest that the gender difference in LNNA-induced tone is based on a gender difference in the regulation of rho-kinase mediated Ca(2+) sensitivity. Rho-kinase and NO thus emerge as critical factors in the regulation of cochlear blood flow. The larger role of NO-dependent mechanisms in male SMAs predicts greater restrictions on cochlear blood flow under
Pungarcher, India; Mourao, Luciana; Davis, Christopher R; Simon, Philipp; Pixley, Kevin V; Tanumihardjo, Sherry A
Background: Crops such as maize, sorghum, and millet are being biofortified with provitamin A carotenoids to ensure adequate vitamin A (VA) intakes. VA assessment can be challenging because serum retinol concentrations are homeostatically controlled and more sensitive techniques are resource-intensive. Objectives: We investigated changes in serum retinol relative differences of isotope amount ratios of 13C/12C (δ13C) caused by natural 13C fractionation in C3 compared with C4 plants as a biomarker to detect provitamin A efficacy from biofortified (orange) maize and high-carotene carrots. Methods: The design was a 2 × 2 × 2 maize (orange compared with white) by carrot (orange compared with white) by a VA fortificant (VA+ compared with VA−) in weanling male Mongolian gerbils (n = 55), which included a 14-d VA depletion period and a 62-d treatment period (1 baseline and 8 treatment groups; n = 5−7/group). Liver VA and serum retinol were quantified, purified by HPLC, and analyzed by GC combustion isotope ratio mass spectrometry for 13C. Results: Treatments affected liver VA concentrations (0.048 ± 0.039 to 0.79 ± 0.24 μmol/g; P < 0.0001) but not overall serum retinol concentrations (1.38 ± 0.22 μmol/L). Serum retinol and liver VA δ13C were significantly correlated (R2 = 0.92; P < 0.0001). Serum retinol δ13C differentiated control groups that consumed white maize and white carrots (−27.1 ± 1.2 δ13C‰) from treated groups that consumed orange maize and white carrots (−21.6 ± 1.4 δ13C‰ P < 0.0001) and white maize and orange carrots (−30.6 ± 0.7 δ13C‰ P < 0.0001). A prediction model demonstrated the relative contribution of orange maize to total dietary VA for groups that consumed VA from mixed sources. Conclusions: Provitamin A efficacy and quantitative estimation of the relative contribution to dietary VA were demonstrated with the use of serum retinol δ13C. This method could be used for maize efficacy or effectiveness studies and with
Postischemic alteration of muscarinic acetylcholine and adenosine A1 binding sites in gerbil brain. Protective effects of a novel vinca alkaloid derivative, vinconate, and pentobarbital using an autoradiographic study.
Araki, T; Kato, H; Kogure, K
We studied the alterations in the binding of muscarinic cholinergic and adenosine A1 receptors following transient cerebral ischemia in Mongolian gerbils and examined the effects of the novel vinca alkaloid derivative vinconate and pentobarbital against the alterations in the binding of these receptors. Animals were allowed to survive for 5 h and 7 days after 10 min of cerebral ischemia induced by bilateral occlusion of common carotid arteries. [3H]Quinuclidinyl benzilate (QNB) and [3H]cyclohexyladenosine (CHA) were used to label muscarinic cholinergic and adenosine A1 receptors, respectively. The [3H]QNB and [3H]CHA bindings showed no significant alteration in the gerbil brain 5 h after ischemia. However, these bindings in the striatum, the hippocampal CA1 sector, and the hippocampal CA3 sector revealed a significant reduction 7 days after ischemia. The [3H]CHA binding also showed a significant decline in the dentate molecular layer 7 days after ischemia. Intraperitoneal application of vinconate (100 and 300 mg/kg) 10 min and pentobarbital (40 mg/kg) 30 min before ischemia showed a mild reduction in the [3H]CHA binding in the brain 5 h after ischemia. Especially, the reduction was found in the hippocampal CA1 sector and the dentate molecular layer. However, the [3H]QNB binding revealed no significant alteration in the brain 5 h after ischemia. Seven days after ischemia, both drugs prevented a marked reduction in the [3H]CHA binding in the striatum, but not in the hippocampal CA1 sector, the hippocampal CA3 sector, and the dentate molecular layer. By contrast, vinconate and pentobarbital failed to prevent the reduction in the [3H]QNB binding in the striatum. Morphological study indicated that vinconate and pentobarbital ameliorated the neuronal damage to the striatum, but not the hippocampal damage 7 days after ischemia. This histological finding was relatively consistent with the alteration in the [3H]CHA binding. These receptor autoradiographic and histological
Tomida, S; Wagner, H G; Klatzo, I; Nowak, T S
Regional cerebral blood flow (rCBF) was compared in the gerbil by means of [3H]nicotine, [14C]-iodoantipyrine, and hydrogen clearance techniques. In agreement with other studies, nicotine and iodoantipyrine methods gave virtually identical results. With these methods, it was observed that a reduction in blood flow occurred shortly after insertion of an electrode into the striatum for hydrogen clearance measurement, affecting rCBF throughout the impaled hemisphere. The reduction was moderate (30%) in the striatum and hippocampus, but much greater (70%) in cortical regions. Identical deficits were observed following brief penetrations involving only cortex. Following chronic electrode placement in the striatum, regional blood flow values obtained with [3H]nicotine returned to the control range within 6 h. Blood flow estimates obtained in the striatum with the implanted electrode increased with a similar time course, so that by 6-24 h, hydrogen clearance gave values indistinguishable from control values obtained with [3H]nicotine. These results clearly demonstrate that reduction of CBF subsequent to electrode placement can account for the low values frequently obtained with the hydrogen clearance method in small animals. The distribution of the deficit and the time course of its recovery are similar to blood flow changes associated with spreading depression. While mechanisms responsible for this effect remain to be fully identified, chronic implantation is a practical solution that allows the continued use of hydrogen clearance as a convenient method for repeated measurement of blood flow in the same animal.
Marié, Jean-Lou; Fournier, Pierre-Edouard; Rolain, Jean-Marc; Briolant, Sébastien; Davoust, Bernard; Raoult, Didier
The prevalences of Bartonella spp. and Rickettsia spp. were investigated using molecular methods in 77 rodent fleas collected in November 2002 by the French forces detachment in Kabul, Afghanistan. Overall, Bartonella DNA was detected in 15.5% of gerbil fleas and 40.5% of rat fleas, whereas Rickettsia felis was found in 9% of gerbil fleas. We described for the first time in this country Bartonella quintana, B. koehlerae, B. taylorii, and Rickettsia felis in fleas from the gerbil species Meriones lybicus, and B. elizabethae and B. doshiae in rat fleas. Of these, B. quintana, B. elizabethae, B. koehlerae, and R. felis are recognized human pathogens. These results emphasize the potential risk of flea-borne infections transmitted by rodents in this area, and suggest that preventive measures should be taken in the general framework of zoonoses management.
Helfert, R.H.; Schwartz, I.R.; Ryan, A.F.
Two populations of olivocochlear (OC) neurons have been identified in the gerbil brain stem on the basis of differential labeling patterns of 3H-D-aspartic acid (D-ASP) and wheatgerm agglutinin-horseradish peroxidase conjugate (WGA/HRP) from the cochlear perilymph. While both populations are capable of uptake and retrograde uptake of WGA/HRP, one population accumulates and retrogradely transports D-ASP (D-ASP OC neurons) and the other does not (non-D-ASP OC neurons). D-ASP OC neurons are found in or near the lateral superior olive, are small in size, and receive very few synaptic contacts. The vast majority of these synapses contain small, mildly pleomorphic vesicles with scattered dense core vesicles. Synapses with distinctly larger pleomorphic vesicles have also been observed. These neurons possess all of the features common to neurons of the lateral olivocochlear system. Non-D-ASP OC neurons are found primarily in the ventral nucleus of the trapezoid body, as well as in the area between the medial superior olive and the medial nucleus of the trapezoid body. These neurons are larger and receive greater numbers and types of synaptic contacts than those found on D-ASP OC neurons. The 2 most common synapses found on non-D-ASP OC neurons are axosomatic ones containing small, mildly pleomorphic vesicles and scattered dense core vesicles similar to those seen on the D-ASP OC neurons, and axodendritic synapses containing large, round vesicles. Much less frequently observed are synapses containing small, round vesicles or ones containing predominantly flat vesicles. The ultrastructural features of the non-D-ASP OC neurons correspond to those described for neurons of the medial olivocochlear system.
Lv, Xiaobo; Yang, Jue; Song, Hui; Li, Tong; Guo, Le; Xing, Yingying; Xi, Tao
Vaccination is an effective means of preventing infectious diseases, including those caused by Helicobacter pylori. In this study, we constructed a novel multi-epitope vaccine, CTB-UE, composed of the cholera toxin B subunit and tandem copies of the B and Th cell epitopes from the H. pylori urease A and B subunits. We evaluated the therapeutic efficacy of the multi-epitope vaccine CTB-UE against H. pylori infection in a Mongolian gerbil model and studied its immuno-protective mechanisms. The experimental results indicated that urease activity, H. pylori colonisation density, the levels of IL-8 and TNF-α in the serum, and the levels of COX-2 and NAP in gastric tissue were significantly lower and the IgG level in the serum and the IFN-γ level in spleen lymphocytes were significantly higher in the vaccinated group compared with the model control group; additionally, gastric mucosal inflammation was notably alleviated following vaccination. The results showed that CTB-UE had a good therapeutic effect on H. pylori infection. The immuno-protective mechanism was closely related to the immune response mediated by microRNA-155, the expression of which was strongly up-regulated after CTB-UE administration. The expression levels of the microRNA-155 target proteins IFN-γRα, AID, and PU.1 were significantly down-regulated; these results indicated that CTB-UE induced an immune response biased towards Th1 cells by up-regulating microRNA-155 to inhibit IFN-γRα expression and induced a humoral immune response towards B cells by up-regulating microRNA-155 to inhibit PU.1 and AID expression. These results demonstrate that the multi-epitope vaccine CTB-UE may be a promising therapeutic vaccine against H. pylori infection and is a new therapeutic tool for human use.
Parab, P B; Rajasekariah, G R; Chandrashekar, R; Alkan, S S; Braun, D G; Subrahmanyam, D
Monoclonal antibodies were produced following immunization of mice with live infective larvae of Brugia malayi. One of these, 46.08.76, is an antibody that promotes adherence of mouse peritoneal macrophages and human peripheral blood leucocytes to the infective larvae of B. malayi and Wuchereria bancrofti, respectively, and kills them. Fresh normal serum, as a source of complement, augments this effect. The same monoclonal antibody conferred 89% protection to jirds (Meriones unguiculatus) against challenge infection of B. malayi stage-three larvae. This monoclonal antibody recognizes antigens of 80,000, 67,000, 52,000 and 36,000 MW proteins present among the antigens of larvae, as detected by an immunoblotting technique. The antibody also reacts with antigens of infective larvae of Litomosoides carinii, Dipetalonema viteae and B. pahangi, but to a smaller extent. Images Figure 1 Figure 2 PMID:3384450
Lower Merion Township School District, Ardmore, PA.
AFTER AN EVALUATION MADE BY THE TEACHERS OF KINDERGARTEN THROUGH GRADE 6, THE FOLLOWING AREAS OF CLARIFICATION, REWRITING, OR ADDITIONS WERE INDICATED--THE PURPOSE AND USE OF THE SCIENCE GUIDE, EVALUATION OF THE UNITS BY GRADES, ADDITIONAL MATERIALS FOR THE UNITS, A REWRITING OF PARTICULAR UNITS, HEALTH UNITS FOR GRADES 1 THROUGH 5, THE USE OF…
Mason, Matthew J
Many species of small desert mammals are known to have expanded auditory bullae. The ears of gerbils and heteromyids have been well described, but much less is known about the middle ear anatomy of other desert mammals. In this study, the middle ears of three gerbils (Meriones, Desmodillus and Gerbillurus), two jerboas (Jaculus) and two sengis (elephant-shrews: Macroscelides and Elephantulus) were examined and compared, using micro-computed tomography and light microscopy. Middle ear cavity expansion has occurred in members of all three groups, apparently in association with an essentially 'freely mobile' ossicular morphology and the development of bony tubes for the middle ear arteries. Cavity expansion can occur in different ways, resulting in different subcavity patterns even between different species of gerbils. Having enlarged middle ear cavities aids low-frequency audition, and several adaptive advantages of low-frequency hearing to small desert mammals have been proposed. However, while Macroscelides was found here to have middle ear cavities so large that together they exceed brain volume, the bullae of Elephantulus are considerably smaller. Why middle ear cavities are enlarged in some desert species but not others remains unclear, but it may relate to microhabitat.
Ribeiro, Wesley Lyeverton Correia; Macedo, Iara Tersia Freitas; dos Santos, Jessica Maria Leite; de Oliveira, Erick Falcão; Camurça-Vasconcelos, Ana Lourdes Fernandes; de Paula, Haroldo Cesar Beserra; Bevilaqua, Claudia Maria Leal
Phytotherapy has been described as an alternative method for the control of gastrointestinal nematodes in small ruminants. Goal of the encapsulation of essential oils in biopolymer matrices is to optimize the biological effects of these oils. The aim of the present study was to evaluate the in vitro and in vivo anthelmintic activity of encapsulated Eucalyptus staigeriana essential oil (EncEs) on the eggs and larvae of Haemonchus contortus. Therefore, the egg hatching test (EHT), larval development test (LDT) and worm load evaluation were performed to evaluate Meriones unguiculatus experimentally infected with H. contortus. The chemical constituents of E. staigeriana essential oil (EsEO) and the in vitro oil release profile from the chitosan matrix at a pH of 1.2 and 7.0 were also characterized. EncEs and EsEO inhibited larval hatching by 97.19% and 99.96% at doses of 1.5 and 1.0 mg ml(-1), respectively. In the LDT, EncEs and EsEO induced a larvicidal effect greater than 95% at concentrations of 5.8 and 8 mg ml(-1), respectively. EncEs and EsEO decreased H. contortus load in M. unguiculatus by 40.51% and 46.44%, respectively. The major chemical constituents of EsEO were (+)-Limonene (72.9%), 1,8-Cineole (9.5%) and o-Cimene (4.6%). The release profile of EsEO was 30% in acid and 25% at neutral pH. The similar efficacy of EncEs and EsEO demonstrates that there was no optimization of anthelmintic action following the encapsulation process. Therefore, the use of new encapsulation matrices with controlled release in the pH of the abomasum should be investigated.
Lengemann, F W; Marchell, T F; Chmielewicz, M; Georgi, J R
Ten radioisotopes (133Ba, 207Bi, 109Cd, 51Cr, 59Fe, 203Hg, 54Mn, 125Sb and 75Se) were used to label the L-3 stage of Brugia malayi. The in vitro uptake at 4 hours in a buffered salt solution was greatest for 207Bi and exceeded that of 203Hg, by a factor of 6 and the rest of the radionuclides by factors of 26 or more. Dimethylsulfoxide (DMSO) (1%) in the medium only slightly enhanced the uptake of 207Bi but increased 203Hg uptake by a factor of 2.5. After incubation in non-radioactive medium only 2% of the 207Bi was retained; for 203Hg the retention was 70% or better. Increasing the labeling time increased total uptake and retention of the radionuclides. The retention of the 203Hg injected intraperitoneally into jirds (Meriones unguiculatus) in the form of labeled L-3s was followed over a 16 day period by counting the jirds in a whole animal NaI crystal detector. One L-4 stage of B malayi was recovered at the end of this period.
Lengemann, F.W.; Marchell, T.F.; Chmielewicz, M.; Georgi, J.R.
Ten radioisotopes (/sup 133/Ba, /sup 207/Bi, /sup 109/Cd, /sup 51/Cr, /sup 59/Fe, /sup 203/Hg, /sup 54/Mn, /sup 125/Sb and /sup 75/Se) were used to label the L-3 stage of Brugia malayi. The in vitro uptake at 4 hours in a buffered salt solution was greatest for /sup 207/Bi and exceeded that of /sup 203/Hg, by a factor of 6 and the rest of the radionuclides by factors of 26 or more. Dimethylsulfoxide (DMSO) (1%) in the medium only slightly enhanced the uptake of /sup 207/Bi but increased /sup 203/Hg uptake by a factor of 2.5. After incubation in non-radioactive medium only 2% of the /sup 207/Bi was retained; for /sup 203/Hg the retention was 70% or better. Increasing the labeling time increased total uptake and retention of the radionuclides. The retention of the /sup 203/Hg injected intraperitoneally into jirds (Meriones unguiculatus) in the form of labeled L-3s was followed over a 16 day period by counting the jirds in a whole animal NaI crystal detector. One L-4 stage of B malayi was recovered at the end of this period.
Dangi, Anil; Vedi, Satish; Nag, Jeetendra Kumar; Paithankar, Sameer; Singh, Mahendra Pratap; Kar, Santosh Kumar; Dube, Anuradha; Misra-Bhattacharya, Shailja
Wolbachia is an intracellular endosymbiont of Brugia malayi parasite whose presence is essential for the survival of the parasite. Treatment of B. malayi-infected jirds with tetracycline eliminates Wolbachia, which affects parasite survival and fitness. In the present study we have tried to identify parasite proteins that are affected when Wolbachia is targeted by tetracycline. For this Wolbachia depleted parasites (B. malayi) were obtained by tetracycline treatment of infected Mongolian jirds (Meriones unguiculatus) and their protein profile after 2-DE separation was compared with that of untreated parasites harboring Wolbachia. Approximately 100 protein spots could be visualized followed by CBB staining of 2-D gel and included for comparative analysis. Of these, 54 showed differential expressions, while two new protein spots emerged (of 90.3 and 64.4 kDa). These proteins were subjected to further analysis by MALDI-TOF for their identification using Brugia coding sequence database composed of both genomic and EST sequences. Our study unravels two crucial findings: (i) the parasite or Wolbachia proteins, which disappeared/down-regulated appear be essential for parasite survival and may be used as drug targets and (ii) tetracycline treatment interferes with the regulatory machinery vital for parasites cellular integrity and defense and thus could possibly be a molecular mechanism for the killing of filarial parasite. This is the first proteomic study substantiating the wolbachial genome integrity with its nematode host and providing functional genomic data of human lymphatic filarial parasite B. malayi.
Mitsui, Y; Takamura, N; Fujimaki, Y; Yamaguchi, T; Kitagawa, T; Aoki, Y
A sensitive and reproducible competitive enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of diethylcarbamazine (DEC) in biological fluids was developed. Since DEC has no functional group to conjugate with bovine serum albumin (BSA), N-(2-aminoethyl)-N-ethyl-4-methyl-1-piperazinecarboxamide (DEC-NH2) was first synthesized. This compound was then converted to carboxyl DEC (DEC-COOH) and conjugated to BSA and to poly-L-lysine for use as immunogen and solid-phase marker, respectively. The competitive ELISA was conducted by simultaneously incubating DEC with mouse anti-DEC antiserum over DEC-poly-L-lysine solid phase. Subsequently, the binding of anti-DEC antibody was detected by using sheep anti-mouse IgG peroxidase conjugate as a tracer. The reliability, determined by the coefficient of variation for inter and intra-assay, was satisfactory. The cross-reactivities of anti-DEC antibodies with DEC metabolites, related compounds and ivermectin were negligible. Using this assay, DEC levels were easily determined in serum of Mongolian jirds (Meriones unguiculatus) up to 4 hours following a single dose of DEC citrate base (100 mg/kg of body weight) via intraperitoneal route.
Matuschka, F R; Spielman, A
To determine whether blackbirds (Turdus merula), the most abundant and most abundantly tick-infested ecotonal bird of Central Europe, may contribute to the transmission of the Lyme disease spirochete (Borrelia burgdorferi), we compared the infectivity to ticks of naturally as well as experimentally infected blackbirds and rodents. European blackbirds experience intense exposure to Ixodes ricinus ticks and to the pathogens that they transmit. In nature, subadult I. ricinus ticks found feeding on these birds generally contain no spirochetes, although infection is universal in those found on black-striped mice (Apodemus agrarius). Those found on yellow-necked mice (A. flavicollis) are less frequently infected. Ticks lose infection in the course of feeding on blackbirds and fail to infect them. Subadult I. ricinus ticks readily feed on blackbirds, black-striped mice, and jirds (Meriones unguiculatus), but engorge less fully on the bird than on the rodents. Although birds may burden human health by establishing new infestations of I. ricinus ticks, our observations indicate that particular birds may benefit health by locally diminishing transmission of the Lyme disease spirochete.
Morick, Danny; Krasnov, Boris R; Khokhlova, Irina S; Gottlieb, Yuval; Harrus, Shimon
Bartonella are emerging and re-emerging pathogens affecting humans and a wide variety of animals including rodents. Horizontal transmission of Bartonella species by different hematophagous vectors is well acknowledged but vertical transmission (from mother to offspring) is questionable and was never explored in fleas. The aim of this study was to investigate whether the rodent flea, Xenopsylla ramesis, can acquire native Bartonella from wild rodents and transmit it transovarially. For this aim, Bartonella-free laboratory-reared X. ramesis fleas were placed on six naturally Bartonella-infected rodents and six species-matched Bartonella-negative rodents (three Meriones crassus jirds, two Gerbillus nanus gerbils and one Gerbillus dasyurus gerbil) for 7 days, 12-14h per day. The fleas that were placed on the Bartonella-positive rodents acquired four different Bartonella genotypes. Eggs and larvae laid and developed, respectively, by fleas from both rodent groups were collected daily for 7 days and molecularly screened for Bartonella. All eggs and larvae from both groups were found to be negative for Bartonella DNA. Interestingly, two of five gut voids regurgitated by Bartonella-positive fleas contained Bartonella DNA. The naturally infected rodents remained persistently infected with Bartonella for at least 89 days suggesting their capability to serve as competent reservoirs for Bartonella species. The findings in this study indicate that X. ramesis fleas can acquire several Bartonella strains from wild rodents but cannot transmit Bartonella transovarially.
Gholamrezaei, Mostafa; Mohebali, Mehdi; Hanafi-Bojd, Ahmad Ali; Sedaghat, Mohammad Mehdi; Shirzadi, Mohammad Reza
Zoonotic cutaneous leishmaniasis (ZCL), caused by Leishmania major, is a common zoonotic vector-borne disease in Iran. Close contact with infected reservoir hosts increases the probability of transmission of Leishmania parasite infections to susceptible humans. Four gerbil species (Rodentia: Gerbillidae) serve as the main reservoir hosts for ZCL in different endemic foci of Iran. These species include Rhombomys opimus, Meriones libycus, Meriones hurrianae and Tatera indica; while notable infection has been reported in Nesokia indica as well. The purpose of this study is to model the distribution of these reservoirs to identify the risk areas of ZCL. A data bank was developed including all published data during the period of 1970-2015. Maximum entropy model was used to find the most appropriate ecological niches for each species. The areas under curve obtained were 0.961, 0.927, 0.922, 0.997 and 0.899, instead of 1, for training test in R. opimus, M. libycus, T. indica, M. hurrianae and N. indica, respectively. The environmental variable with the highest gain when used in isolation was slope for R. opimus and N. indica, annual mean temperature for M. libycus, and seasonal precipitation for T. indica and M. hurrianae. Summation of presence probabilities for three main species, i.e., R. opimus, M. libycus and T. indica revealed favorable ecological niches in wide areas of 16 provinces. This is the first study to predict the distribution of ZCL reservoir hosts in Iran. Climatology and topography variables had high contributions toward the prediction of potential distribution of the main reservoir species; therefore, as climate changes, the models should be updated periodically with novel data, and the results should be used in disease-monitoring programs.
Lucius, R.; Textor, G.; Kern, A.; Kirsten, C. )
Jirds (Meriones unguiculatus) were immunized with irradiated (35 krad) stage-3 larvae (L3) of Acanthocheilonema viteae. The induced resistance against homologous challenge infection and the antibody response of the animals were studied. Immunization with 3, 2, or 1 dose of 50 irradiated L3 induced approximately 90% resistance. Immunization with a single dose of only 5 irradiated L3 resulted in 60.8% protection while immunization with a single dose of 25 L3 induced 94.1% protection. The protection induced with 3 doses of 50 irradiated L3 did not decrease significantly during a period of 6 months. Sera of a proportion, but not all resistant jirds, contained antibodies against the surface of vector derived L3 as defined by IFAT. No surface antigens of microfilariae or adult worms were recognized by the sera. Vaccinated animals had antibody responses against antigens in the inner organs of L3 and in the cuticle and reproductive organs of adult worms as shown by IFAT. Immunoblotting with SDS-PAGE-separated L3 antigens and L3-CSN revealed that all sera contained antibodies against two exported antigens of 205 and 68 kDa, and against a nonexported antigen of 18 kDa. The 205-kDa antigen easily degraded into fragments of 165, 140, 125, and 105 kDa which were recognized by resistant jird sera. Various antigens of adult worms, but relatively few antigens of microfilariae, were also recognized. To test the relevance of exported antigens of L3 to resistance, jirds were immunized with L3-CSN together with a mild adjuvant. This immunization induced 67.7% resistance against challenge infection and sera of the immunized animals recognized the 205- and 68-kDa antigens of L3.
Verma, Meenakshi; Pathak, Manisha; Shahab, Mohd; Singh, Kavita; Mitra, Kalyan; Misra-Bhattacharya, Shailja
Moxidectin is a macrocyclic lactone belonging to milbemycin family closely related to ivermectin and is currently progressing towards Phase III clinical trial against human infection with the filaria Onchocerca volvulus (Leuckart, 1894). There is a single report on the microfilaricidal and embryostatic activity of moxidectin in case of the human lymphatic filarial parasite Brugia malayi (Brug, 1927) in Mastomys coucha (Smith) but without any adulticidal action. In the present study, the in vitro and in vivo antifilarial efficacy of moxidectin was evaluated on, B. malayi. In vitro moxidectin showed 100% reduction in adult female worm motility at 0.6 μM concentration within 7 days with 68% inhibition in the reduction of MTT (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide dye) (which is used to detect viability of worms). A 50% inhibitory concentration (IC50) of moxidectin for adult female parasite was 0.242 μM, for male worm 0.186 μM and for microfilaria IC50 was 0.813 μM. In adult B. malayi-transplanted primary screening model (Meriones unguiculatus Milne-Edwards), moxidectin at a single optimal dose of 20 mg/kg by oral and subcutaneous route was found effective on both adult parasites and microfilariae. In secondary screening (M coucha, subcutaneously inoculated with infective larvae), moxidectin at the same dose by subcutaneous route brought about death of 49% of adult worms besides causing sterilisation in 54% of the recovered live female worms. The treated animals exhibited a continuous and sustained reduction in peripheral blood microfilaraemia throughout the observation period of 90 days. The mechanism of action of moxidectin is suggested to be similar to avermectins. The in silico studies were also designed to explore the interaction of moxidectin with glutamate-gated chloride channels of B. malayi. The docking results revealed a close interaction of moxidectin with various GluCl ligand sites of B. malayi.
Kváč, Martin; McEvoy, John; Loudová, Martina; Stenger, Brianna; Sak, Bohumil; Květoňová, Dana; Ditrich, Oleg; Rašková, Veronika; Moriarty, Elaine; Rost, Michael; Macholán, Miloš; Piálek, Jaroslav
Two house mouse subspecies occur in Europe, eastern and northern Mus musculus musculus (Mmm) and western and southern Mus musculus domesticus (Mmd). A secondary hybrid zone occurs where their ranges meet, running from Scandinavia to the Black Sea. In this paper, we tested a hypothesis that the apicomplexan protozoan species Cryptosporidium tyzzeri has coevolved with the house mouse. More specifically, we assessed to what extent the evolution of this parasite mirrors divergence of the two subspecies. In order to test this hypothesis, we analysed sequence variation at five genes (ssrRNA, Cryptosporidium oocyst wall protein (COWP), thrombospondin-related adhesive protein of Cryptosporidium 1 (TRAP-C1), actin and gp60) in C. tyzzeri isolates from Mmd and Mmm sampled along a transect across the hybrid zone from the Czech Republic to Germany. Mmd samples were supplemented with mice from New Zealand. We found two distinct isolates of C. tyzzeri, each occurring exclusively in one of the mouse subspecies (C. tyzzeri-Mmm and C. tyzzeri-Mmd). In addition to genetic differentiation, oocysts of the C. tyzzeri-Mmd subtype (mean: 4.24×3.69μm) were significantly smaller than oocysts of C. tyzzeri-Mmm (mean: 4.49×3.90 μm). Mmm and Mmd were susceptible to experimental infection with both C. tyzzeri subtypes; however, the subtypes were not infective for the rodent species Meriones unguiculatus, Mastomys coucha, Apodemus flavicollis or Cavia porcellus. Overall, our results support the hypothesis that C. tyzzeri is coevolving with Mmm and Mmd.
Kváč, Martin; McEvoy, John; Loudová, Martina; Stenger, Brianna; Sak, Bohumil; Květoňová, Dana; Ditrich, Oleg; Rašková, Veronika; Moriarty, Elaine; Rost, Michael; Macholán, Miloš; Piálek, Jaroslav
Two house mouse subspecies occur in Europe, eastern and northern Mus musculus musculus (Mmm) and western and southern Mus musculus domesticus (Mmd). A secondary hybrid zone occurs where their ranges meet, running from Scandinavia to the Black Sea. In this paper, we tested a hypothesis that the apicomplexan protozoan species Cryptosporidium tyzzeri has coevolved with the house mouse. More specifically, we assessed to what extent the evolution of this parasite mirrors divergence of the two subspecies. In order to test this hypothesis, we analyzed sequence variation at five genes (ssrRNA, Cryptosporidium oocyst wall protein (COWP), thrombospondin-related adhesive protein of Cryptosporidium 1 (TRAP-C1), actin and gp60) in C. tyzzeri isolates from Mmd and Mmm sampled along a transect across the hybrid zone from the Czech Republic to Germany. Mmd samples were supplemented with mice from New Zealand. We found two distinct isolates of C. tyzzeri, each occurring exclusively in one of the mouse subspecies (C. tyzzeri-Mmm and C. tyzzeri-Mmd). In addition to genetic differentiation, oocysts of the C. tyzzeri-Mmd subtype (mean: 4.24 × 3.69 μm) were significantly smaller than oocysts of C. tyzzeri-Mmm (mean: 4.49 × 3.90 μm). Mmm and Mmd were susceptible to experimental infection with both C. tyzzeri subtypes; however, the subtypes were not infective for the rodent species Meriones unguiculatus, Mastomys coucha, Apodemus flavicollis or Cavia porcellus. Overall, our results support the hypothesis that C. tyzzeri is coevolving with Mmm and Mmd. PMID:23791796
Shakya, Shilpy; Bajpai, Preeti; Sharma, Sharad; Misra-Bhattacharya, Shailja
The discovery of the endosymbiont Wolbachia, which has a mutualistic relationship with filarial nematodes, and its importance in filarial parasite biology has provided a lead for developing novel chemotherapeutic agents against human filariasis. Wolbachia also appears to be involved in immunopathological responses as well as adverse reactions after antifilarial therapy. The aim of the present study was to explore the potential of administering anti-Wolbachial therapy before antifilarial treatment to improve the filaricidal efficacy of the present-day filaricide diethylcarbamazine. An additional objective was to minimize host inflammatory reactions using a rodent model Mastomys coucha and Meriones unguiculatus infected with human lymphatic filariid Brugia malayi. We observed: (1) a 40-day treatment schedule of tetracycline alone resulted in delayed reduction in microfilaraemia and a low degree of macrofilaricidal efficacy; (2) tetracycline therapy followed by 100 mg/kg diethylcarbamazine (DEC) x5 days led to marked reduction in microfilaraemia from day 48 onward after initiation of treatment. The combination treatment also brought about approximately 70% death of adult B. malayi and sterilization of 82.3% of the surviving female worms, thus exhibiting remarkable enhancement in the antifilarial activity of DEC; (3) tissue inflammatory reactions and pathogenesis were significantly reduced as observed by histopathology, and peritoneal macrophage mediated oxidative burst shown by fluorescence-activated cell sorting (FACS) analysis using dichlorofluorescein diacetate (DCF-DA); and (4) the characteristic filarial antigen-specific and mitogen-specific cellular unresponsiveness was significantly reversed, possibly due to marked clearance of microfilaraemia. It is therefore advisable to give an anti-Wolbachial antibiotic trial before starting antifilarial therapy to achieve maximum benefits.
Dobrota, Dusan; Fedorova, Tatiana; Stvolinsky, Sergey; Babusikova, Eva; Likavcanova, Katarina; Drgova, Anna; Strapkova, Adriana; Boldyrev, Alexander
Carnosine, a specific constituent of excitable tissues of vertebrates, exhibits a significant antioxidant protecting effect on the brain damaged by ischemic-reperfusion injury when it was administered to the animals before ischemic episode. In this study, the therapeutic effect of carnosine was estimated on animals when this drug was administered intraperitoneally (100 mg/kg body weight) after ischemic episode induced by experimental global brain ischemia. Treatment of the animals with carnosine after ischemic episode under long-term (7-14 days) reperfusion demonstrated its pronounced protective effect on neurological symptoms and animal mortality. Carnosine also prevented higher lipid peroxidation of brain membrane structures and increased a resistance of neuronal membranes to the in vitro induced oxidation. Measurements of malonyl dialdehyde (MDA) in brain homogenates showed its increase in the after brain stroke animals and decreased MDA level in the after brain stroke animals treated with carnosine. We concluded that carnosine compensates deficit in antioxidant defense system of brain damaged by ischemic injury. The data presented demonstrate that carnosine is effective in protecting the brain in the post-ischemic period.
Nam, Jong-Hoon; Liu, Yanju; Gracewski, Sheryle M.
Through model simulations, we investigated the cochlear traveling waves formed by outer hair cell (OHC) motility. Two sets of governing equations, one representing the solid domain of the organ of Corti complex (OCC) and the other representing the fluid domain, were solved simultaneously in the time domain. The OHCs incorporated electro-mechanical motility driven by prestin molecules. The combined fluid-solid interaction model was verified by simulating passive traveling waves along the cochlear coil. When stimulated with an electrical impulse, the OCC formed traveling waves propagating toward the apex. Without the Y-shaped structures in the OCC formed by the OHCs and the Deiter's cell processes, the active OHCs form dispersive waves rather than traveling waves upon electrical stimulation.
Takeuchi, S; Ando, M; Kozakura, K; Saito, H; Irimajiri, A
The basolateral membrane of isolated strial marginal cells has been probed for conductive pathways by the patch-clamp technique. Two types of voltage-insensitive channels were identified in both cell-attached and excised patches. Of these, frequently (69% of excised patches) observed was a Ca(2+)-activated nonselective cation channel having a unit conductance of 24.9 +/- 0.5 pS (N = 16). Other characteristics of this type in excised patches include: 1) linear I-V relations with 150 mM K+ (pipette)/150 mM Na+ (bath), 2) a permeability sequence of NH4+ > Na+ = K+ = Rb+ > Li+, 3) a flickering block by quinine or quinidine (both 1 mM), and 4) a dose dependent block of its activity by ADP or ATP (IC50,ATP/IC50,ADP = 20-35), both from the cytosolic side. Channels with similar characteristics were found in the apical membrane of the same cell; however, the basolateral channels were 2-4 times more densely distributed than the apical counterparts. Also frequently (57%) detected was a Cl- channel of 80.0 +/- 0.5 pS (N = 6), whose activity was Ca2+ independent. Additionally, this Cl- channel had: 1) linear I-V relations with symmetric Cl-, 2) a permeability sequence of Cl- > Br- > I- > or = NO3- > or = gluconate-, and 3) a complete and reversible block by 1 mM diphenylamine-2-carboxylate. In contrast to the apical Cl- channels, the basolateral ones had a much higher density (57% vs. < 1%) as well as a higher unit conductance (80 pS vs. 50 pS) than the apical counterpart. The relative abundance of these two types as the major conductive pathways for Na+, K+, and Cl- in the basolateral region must be taken into account when addressing the role of strial marginal cells in generating the positive endocochlear potential. The Cl- channel may facilitate Cl- distribution across the basolateral membrane.
Willey, D.W.; van Riper, Charles
We studied first-year movements of Mexican Spotted Owls (Strix occidentalis lucida) during natal dispersal in canyonlands of southern Utah. Thirty-one juvenile Mexican Spotted Owls were captured and radiotracked during 1992-95 to examine behavior and conduct experiments related to the onset of natal dispersal. Juvenile Spotted Owls dispersed from their nest areas during September to October each year, with 85% leaving in September. The onset of movements was sudden and juveniles dispersed in varied directions. The median distance from nest area to last observed location was 25.7 km (range = 1.7-92.3 km). Three of 26 juveniles tracked (11%) were alive after one year, although none were observed with mates. We conducted a feeding experiment, using Mongolian gerbils (Meriones unguicuculatus), to test the influence of increased food supply on dispersal onset. The mean dispersal date of five owls that received supplemental food (Julian day no. 255 ?? 2.6 SD) was significantly different than a control group (day no. 273 ?? 12.3).
Ceballos, Laura; Mackenzie, Charles; Geary, Timothy; Alvarez, Luis; Lanusse, Carlos
The goal of elimination of the human filariases would benefit greatly from the use of a macrofilaricidal agent. In vivo trials in humans and many experimental animal models suggest that flubendazole (FLBZ) is a highly efficacious macrofilaricide. However, since serious injection site reactions were reported in humans after parenteral FLBZ administration, the search for alternative pharmaceutical strategies to improve the systemic availability of FLBZ and its metabolites has acquired urgency in both human and veterinary medicine. The goal of the current work was to compare the systemic exposure of FLBZ formulated as either an aqueous hydroxypropyl-β-cyclodextrin (CD) or aqueous carboxymethyl cellulose (CMC) suspension or a Tween 80-based formulation (TWEEN) in rats and jirds (Meriones unguiculatus). Healthy animals of both species were allocated into four experimental groups of 44 animals each: FLBZ-CDoral and FLBZ-CDsc, treated with the FLBZ-CD formulation by the oral or subcutaneous routes, respectively; FLBZ-TWEENsc, dosed subcutaneously with the FLBZ-TWEEN formulation; and FLBZ-CMCoral, treated orally with the FLBZ suspension. The FLBZ dose was 5 mg/kg. FLBZ and its hydrolyzed (H-FLBZ) and reduced (R-FLBZ) metabolites were recovered in plasma samples collected from rats and jirds treated with the different FLBZ formulations. In both species, FLBZ parent drug was the main analyte recovered in the bloodstream. In rats, FLBZ systemic exposure (AUC0-LOQ) was significantly (P<0.05) higher after the FLBZ-CD treatments, both oral (4.8±0.9 µg.h/mL) and subcutaneous (7.3±0.6 µg.h/mL), compared to that observed after oral administration of FLBZ-CMC suspension (0.93±0.2 µg.h/mL). The same differences were observed in jirds. In both species, parenteral administration of FLBZ-TWEEN did not improve the systemic availability of FLBZ compared to FLBZ-CDoral treatment. In conclusion, formulation approaches that enhance the availability of flubendazole in the rat and jird
Batrel, Charlène; Huet, Antoine; Hasselmann, Florian; Wang, Jing; Desmadryl, Gilles; Nouvian, Régis
Auditory nerve fibers (ANFs) transmit acoustic information from the sensory hair cells to the cochlear nuclei. In experimental and clinical audiology, probing the whole ANF population remains a difficult task, as the ANFs differ greatly in their threshold and onset response to sound. Thus, low spontaneous rate (SR) fibers, which have rather higher thresholds, delay and larger jitter in their first spike latency are not detectable in the far-field compound action potential of the auditory nerve. Here, we developed a new protocol of acoustic stimulation together with electrophysiological signal processing to track the steady state activity of ANFs. Mass potentials at the round window were recorded in response to repetitive 300-ms bursts of 1/3 octave band noise centered on a frequency probe. Analysis was assessed during the last 200-ms of the response to capture the steady-state response of ANFs. To eliminate the microphonic component reflecting the sensory cells activity, repetitive pairs of sounds of opposite polarities were used. The spectral analysis was calculated on the average of two consecutive responses, and the neural gain was calculated by dividing point-by-point the spectrum to sound over unstimulated condition. In response to low-sound-level stimulation, neural gain predominated in the low-frequency cochlear regions, while a second component of responses centered on higher cochlear frequency regions appeared beyond 30 dB SPL. At 60 dB SPL, neural gain showed a bimodal shape, with a notch near 5.6 kHz. In addition to correlate with the functional mapping of ANFs along the tonotopic axis, the deletion of low-SR fibers leads to a reduction in the high-frequency response, where the low-SR fibers are preferentially located. Thus, mass potentials at the round window may provide a useful tool to probe the SR-based distribution of ANFs in humans and in other species in which direct single-unit recordings are difficult to achieve or not feasible. PMID:28085968
Photocopy of photograph (source and date unknown) FRONT ELEVATION - Merion Friends Meeting House, 615 Montgomery Avenue (changed from Montgomery Avenue & Meetinghouse Lane), Narberth, Montgomery County, PA
Tziridis, Konstantin; Ahlf, Sönke; Jeschke, Marcus; Happel, Max F. K.; Ohl, Frank W.; Schulze, Holger
In this study, we describe differences between neural plasticity in auditory cortex (AC) of animals that developed subjective tinnitus (group T) after noise-induced hearing loss (NIHL) compared to those that did not [group non-tinnitus (NT)]. To this end, our analysis focuses on the input activity of cortical neurons based on the temporal and spectral analysis of local field potential (LFP) recordings and an in-depth analysis of auditory brainstem responses (ABR) in the same animals. In response to NIHL in NT animals we find a significant general reduction in overall cortical activity and spectral power as well as changes in all ABR wave amplitudes as a function of loudness. In contrast, T-animals show no significant change in overall cortical activity as assessed by root mean square analysis of LFP amplitudes, but a specific increase in LFP spectral power and in the amplitude of ABR wave V reflecting activity in the inferior colliculus (IC). Based on these results, we put forward a refined model of tinnitus prevention after NIHL that acts via a top-down global (i.e., frequency-unspecific) inhibition reducing overall neuronal activity in AC and IC, thereby counteracting NIHL-induced bottom-up frequency-specific neuroplasticity suggested in current models of tinnitus development. PMID:25713557
ß-cryptoxanthin is a precursor to vitamin A and has other potential health benefits. However, there is a lack of knowledge regarding its metabolism, storage, and dose-response effects. This study investigated the whole body metabolism of ß-cryptoxanthin in an appropriate small animal model for huma...
Rautenberg, Philipp L; Grothe, Benedikt; Felmy, Felix
In the mammalian medial superior olive (MSO), neurons compute the azimuthal location of sound sources by temporally precise coincidence detection. It is assumed that the dendritic morphology of MSO neurons plays a crucial role in this computational process. However, few quantitative data about the morphology of these neuronal coincidence detectors are available, limiting theoretical approaches. Such a quantitative morphological description of neurons of the mammalian MSO would also allow a comparative analysis with its avian analog, the nucleus laminaris. We used single-cell electroporation, microscopic reconstruction, and compartmentalization to extract anatomical parameters of MSO neurons and quantitatively describe their morphology and development between postnatal day 9 and 36. We found that developmental refinement occurs until P27, generating morphologically compact, cylinder-like cells with axons originating from the soma. The complexity of higher order dendrites decreases between postnatal days 9 and 21. This decrease in dendritic complexity is judged from counting and analyzing the location of dendritic branches and determining the distribution of the surface area and total length of neurons. During this developmental period, the average length of terminal branches increases about twofold, indicating an elimination of predominantly small branches. The cell volume increases more than 1.5-fold between P9 and P27, a change that can be attributed to an increase in dendritic diameter during this developmental period. The developmental profile of the morphology of MSO neurons obtained indicates that maturation is reached 2 weeks after hearing onset.
3. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 NORTHEAST ELEVATION. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
10. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 MANTEL (NOT ORIGINAL) SOUTHEAST PARLOR. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
14. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 INTERIOR DETAIL, SOUTHEAST BEDROOM. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
7. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 SOUTH (FRONT) ELEVATION. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
4. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 SOUTHWEST ELEVATION. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
Historic American Buildings Survey, Stanley P. Mixon, Photographer, September 12, 1940 EXTERIOR DETAIL OF END GABLE OF ELL ADDED TO ORIGINAL BUILDING. - Merion Friends Meeting House, 615 Montgomery Avenue (changed from Montgomery Avenue & Meetinghouse Lane), Narberth, Montgomery County, PA
Historic American Buildings Survey, D.H. Smith, Photographer, 1923 VIEW OF FRONT AND SIDE. - Merion Friends Meeting House, 615 Montgomery Avenue (changed from Montgomery Avenue & Meetinghouse Lane), Narberth, Montgomery County, PA
Historic American Buildings Survey, Stanley P. Mixon, Photographer, September 12, 1940 EXTERIOR, GENERAL VIEW OF ORIGINAL MEETING, FROM WEST, SHOWING CORNER PRIVIES. - Merion Friends Meeting House, 615 Montgomery Avenue (changed from Montgomery Avenue & Meetinghouse Lane), Narberth, Montgomery County, PA
... (Sub-No. 1X)] East Penn Railroad, LLC--Abandonment Exemption--in Montgomery County, PA East Penn... Bridgeport, and milepost 2.14 at Henderson Road in Upper Merion Township, in Montgomery County, Pa. The...
Beckett, Amber C; Piazuelo, M Blanca; Noto, Jennifer M; Peek, Richard M; Washington, M Kay; Algood, Holly M Scott; Cover, Timothy L
Epidemiologic studies have provided conflicting data regarding an association between Helicobacter pylori infection and iron deficiency anemia (IDA) in humans. Here, a Mongolian gerbil model was used to investigate a potential role of H. pylori infection, as well as a possible role of diet, in H. pylori-associated IDA. Mongolian gerbils (either H. pylori infected or uninfected) received a normal diet or one of three diets associated with increased H. pylori virulence: high-salt, low-iron, or a combination of a high-salt and low-iron diet. In an analysis of all infected animals compared to uninfected animals (independent of diet), H. pylori-infected gerbils had significantly lower hemoglobin values than their uninfected counterparts at 16 weeks postinfection (P < 0.0001). The mean corpuscular volume (MCV) and serum ferritin values were significantly lower in H. pylori-infected gerbils than in uninfected gerbils, consistent with IDA. Leukocytosis and thrombocytosis were also detected in infected gerbils, indicating the presence of a systemic inflammatory response. In comparison to uninfected gerbils, H. pylori-infected gerbils had a higher gastric pH, a higher incidence of gastric ulcers, and a higher incidence of fecal occult blood loss. Anemia was associated with the presence of gastric ulceration but not gastric cancer. Infected gerbils consuming diets with a high salt content developed gastric ulcers significantly more frequently than gerbils consuming a normal-salt diet, and the lowest hemoglobin levels were in infected gerbils consuming a high-salt/low-iron diet. These data indicate that H. pylori infection can cause IDA and that the composition of the diet influences the incidence and severity of H. pylori-induced IDA.
Bochkov, Andre V
Mites of the family Myocoptidae (Acariformes: Sarcoptoidea) of the former USSR are revised based on the collection of the Zoological Institute RAS (St. Petersburg, Russia). Seventeen described species are recorded. Four species are described as new for science: Trichoecius dubininae sp. nov. from Lasiopodomys gregalis (Pallas) (Rodentia: Cricetidae) from Russia (Chelyabinsk Prov., type locality), Kazakhstan and Kirghizia, T. lemmus sp. nov. from Lemmus sibiricus (Kerr) (Rodentia: Cricetidae) from Russia (Taymyr peninsula), T. meriones sp. nov. from Meriones meridianus (Pallas) (Rodentia: Muridae) from Turkmenia, and Myocoptes meriones sp. nov. from Meriones tamariscinus (type host) from Kirghizia (type locality) and Meriones libycus (Lichtenstein) from Tajikistan. In addition, the presence of 7 more species in the fauna of the former USSR is considered highly probable. Myocoptids of the former USSR represent all 6 genera currently recognized in the family. Keys to species, their hosts and localities are provided and all data are summarized in tabular format. A new name Apocalyptoides nom. nov. is proposed for the preoccupied generic name Apocalypsis Bochkov, 2010 not Butler (1876).
Sahabi, Z; Goodarzian, P; Nadim, A
For the study of the seasonal and hourly activity of the great gerbil, Rhombomys opimus in an endemic focus of zoonotic cutaneous leishmaniasis (Isfahan), two colonies were selected in which the number of gerbils was counted by visual sighting. The study shows that the gerbils are quite active from August through December. After a decrease in January and February, once again they become active but not as much as early Autumn. In the hot months of the year the gerbils are active only early in the morning and late in the afternoon. In the cooler months, they are active in the middle of the day. In cold parts of the year the activity of gerbils decreases very considerably.
Reversal of age-related increase in brain protein oxidation, decrease in enzyme activity, and loss in temporal and spatial memory by chronic administration of the spin-trapping compound N-tert-butyl-alpha-phenylnitrone
Carney, J.M.; Starke-Reed, P.E.; Oliver, C.N.; Landum, R.W.; Cheng, M.S.; Wu, J.F.; Floyd, R.A. )
Oxygen free radicals and oxidative events have been implicated as playing a role in bringing about the changes in cellular function that occur during aging. Brain readily undergoes oxidative damage, so it is important to determine if aging-induced changes in brain may be associated with oxidative events. Previously we demonstrated that brain damage caused by an ischemia/reperfusion insult involved oxidative events. In addition, pretreatment with the spin-trapping compound N-tert-butyl-alpha-phenylnitrone (PBN) diminished the increase in oxidized protein and the loss of glutamine synthetase (GS) activity that accompanied ischemia/reperfusion injury in brain. We report here that aged gerbils had a significantly higher level of oxidized protein as assessed by carbonyl residues and decreased GS and neutral protease activities as compared to young adult gerbils. We also found that chronic treatment with the spin-trapping compound PBN caused a decrease in the level of oxidized protein and an increase in both GS and neutral protease activity in aged Mongolian gerbil brain. In contrast to aged gerbils, PBN treatment of young adult gerbils had no significant effect on brain oxidized protein content or GS activity. Male gerbils, young adults (3 months of age) and retired breeders (15-18 months of age), were treated with PBN for 14 days with twice daily dosages of 32 mg/kg. If PBN administration was ceased after 2 weeks, the significantly decreased level of oxidized protein and increased GS and neutral protease activities in old gerbils changed in a monotonic fashion back to the levels observed in aged gerbils prior to PBN administration. We also report that old gerbils make more errors than young animals and that older gerbils treated with PBN made fewer errors in a radial arm maze test for temporal and spatial memory than the untreated aged controls.
Morsy, T A; Sabry, A H; Rifaat, M M; Wahba, M M
In the Middle East, the fat sand rat Psammomys obesus is the most important reservoir host of zoonotic cutaneous leishmamiasis (ZCL). It is the most incriminated host in outbreaks. Two P. obesus caught in Wadi El Gedeiret (Al Arish, North Sinai) were found naturally infected with Leishmania major as indicated by enzyme electrophoresis. In Egypt, the already known reservoir hosts are Gerbillus pyramidum I. Geoffroy St. Hilaire, 1825; Meriones crassus Sundevall, 1984 and Meriones sacramenti Thomas, 1922. The hostal role of P. obesus was discussed.
Chatterjee, Z. Hashin, and R.B. Pipes ct:• Materials Sciences Corporation B2ue Bell Office Campus Merion-Towle House Blue Bell, PA 19422 August 1979 Final...Materials Sciences Corporation Blue Bell Office Campus Merion-lowle House Blue Bell, PA 19422 d~ ~~ ocuou M or P b c r Jera Im I IC TV Ii~~ `-A \\~ W 5t...Campus erion-Towle House -al •e _B ll • 194’ It. CONTTROLLINc.OFFICE NAME ANO ADDRESS 12. REIPORT DATE Naval Air Development Center b7 Warminster, PA 19422
9. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 CLOSE-UP OF SMALL FRONT FIREPLACE, SOUTHWEST ROOM. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
11. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 SOUTHWEST ROOM SHOWING ORIGINAL CORNER FIREPLACE, OPENING BEHIND BAR. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
8. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 REEDING DETAIL OF MANTEL IN NORTHEAST PARLOR. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
2. Historic American Buildings Survey, Copy of an eary photograph, courtesy of Montgomery County Historical Society, Norristown, Pa., THE KING OF PRUSSIA INN, c.1880. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
13. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 STAIR DETAIL, SECOND FLOOR LEVEL (INSPECTION OF STAIR REVEALS PRESENCE OF A STRING OPPOSITE BANNISTER ORIGINALLY). - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
6. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 NORTHWEST ROOM SHOWING COOK FIREPLACE, ORIGINAL MANTEL, CRANE AND OPENING FOR BAKE OVEN. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
12. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 CLOSE-UP DETAIL OF CORNER FIREPLACE. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
1. Historic American Buildings Survey, Copy of an eary photograph, courtesy of Montgomery County Historical Society, Norristown, Pa., THE KING OF PRUSSIA INN, c.1860-1870. - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
5. Historic American Buildings Survey, Pierre LeBoutillier and Trusten M. Baldwin, Photographers, April, 1960 INTERIOR DETAIL, NORTHEAST AND SOUTHEAST PARLORS, ORIGINAL MANTEL (LEFT - RADIATOR COVERED). - King of Prussia Inn, U.S. Route 202 (Upper Merion Township), King of Prussia, Montgomery County, PA
of Kentucky bluegrass (Poa pratensis L. var. ’Merion’), red fescue ( Festuca rubra L. var. ’Pennlawn’) and annual ryegrass. The mixtures were grown in...turfgrass mixtures. A mixture of tall fescue ( Festuca arundinacea Scheb var. ’K-31’) and annual ryegrass (Lolium multiflorum Lam.) was compared to a mixture
Describes the activities of Dr. Albert Barnes and the Barnes Foundation Galleries in Merion, Pennsylvania, in promoting Black art and supporting Black artists through research and education grants. Focuses on the educative relationship between Dr. Barnes and four Black artists who became accomplished university art teachers. (Author/MJL)
This paper examines the progressive understanding of art advanced by Albert Barnes, and asks how the educational vision for his large collection of art might be preserved as it has now moves from its location in the idyllic suburban setting in Merion, PA to the hustle and bustle of central Philadelphia. I submit that the vision will be endangered…
paper was then placed over the fibers on the net and the mat was dried in place. The net was then separated from the filter paper , leaving a thin...E-ME-MM, Mr. W. A. Wilson, Building 4720 1 Materials Sciences Corporation, Blue Bell Campus, Merion Towle Building, Elue Bell, Pennsylvania 19422
School Science Review, 1977
Includes procedures for demonstrating anaerobic respiration in peas, isolating virgin Drosophila females, solving mortality problems in young gerbils, measuring dissolved oxygen, constructing models for transpiration and DNA molecules, freezing chick embryos, mixing nutrient media, illustrating Darwinian ecological principles, and detecting…
... to be seen with the naked eye Furry animals: cats, dogs, guinea pigs, gerbils, rabbits, and other ... Clothing and toys: made, trimmed, or stuffed with animal hair Latex: household and school articles, such as ...
Quihui-Cota, Luis; León-Trujillo, Rocio; Astiazarán-García, Humberto; Esparza-Romero, Julián; del Refugio Robles, María; Robles-Zepeda, Ramón E; Canett, Rafael; Sánchez-Escalante, Jesús
Human giardiosis is a public health problem in Mexico, where the national prevalence was estimated to be up to 68%. Misuse of antiprotozoal drugs may result in low effectiveness and undesirable side effects. Research on natural products is a good strategy for discovering more effective antiparasitic compounds. This study evaluated the antigiardial activity of extracts of Yucca baccata, which is native to northwestern Mexico. Forty-two gerbils (females) were weighed and orally inoculated with 5 × 10(6) Giardia trophozoites. Two gerbils were selected at random to confirm infection. Forty living gerbils were randomly allocated into 5 treatment groups (8 per group). Gerbils were randomly assigned to be treated with 24.4 mg/mL, 12.2 mg/mL, and 6.1 mg/mL of extracts, metronidazole (2 mg/mL) or PBS, which were intragastrically administered once per day for 3 days. Nine gerbils died during the study course. On day 10 postinfection, gerbils were euthanized and trophozoites were quantified. Yucca extracts reduced, albeit not significantly, the trophozoite counts in the duodenum segment. Only the high-extract concentration significantly reduced the trophozoite counts in the proximal segment and it was similar to that of metronidazole. Extracts of Y. baccata may represent an effective and natural therapeutic alternative for human giardiosis.
Embar, Keren; Raveh, Ashael; Hoffmann, Ishai; Kotler, Burt P
In predator-prey foraging games, the prey's reaction to one type of predator may either facilitate or hinder the success of another predator. We ask, do different predator species affect each other's patch selection? If the predators facilitate each other, they should prefer to hunt in the same patch; if they interfere, they should prefer to hunt alone. We performed an experiment in a large outdoor vivarium where we presented barn owls (Tyto alba) with a choice of hunting greater Egyptian gerbils (Gerbillus pyramidum) in patches with or without Saharan horned vipers (Cerastes cerastes). Gerbils foraged on feeding trays set under bushes or in the open. We monitored owl location, activity, and hunting attempts, viper activity and ambush site location, and the foraging behavior of the gerbils in bush and open microhabitats. Owls directed more attacks towards patches with vipers, and vipers were more active in the presence of owls. Owls and vipers facilitated each other's hunting through their combined effect on gerbil behavior, especially on full moon nights when vipers are more active. Owls forced gerbils into the bushes where vipers preferred to ambush, while viper presence chased gerbils into the open where they were exposed to owls. Owls and vipers took advantage of their indirect positive effect on each other. In the foraging game context, they improve each other's patch quality and hunting success.
Quihui-Cota, Luis; León-Trujillo, Rocio; Astiazarán-García, Humberto; Esparza-Romero, Julián; Robles, María del Refugio; Robles-Zepeda, Ramón E.; Canett, Rafael; Sánchez-Escalante, Jesús
Human Giardiosis is a public health problem in Mexico, where the national prevalence was estimated to be up to 68%. Misuse of antiprotozoal drugs may result in low effectiveness and undesirable side effects. Research on natural products is a good strategy for discovering more effective antiparasitic compounds. This study evaluated the antigiardial activity of extracts of Yucca baccata, which is native to northwestern Mexico. Forty-two gerbils (females) were weighed and orally inoculated with 5 × 106 Giardia trophozoites. Two gerbils were selected at random to confirm infection. Forty living gerbils were randomly allocated into 5 treatment groups (8 per group). Gerbils were randomly assigned to be treated with 24.4 mg/mL, 12.2 mg/mL, and 6.1 mg/mL of extracts, metronidazole (2 mg/mL) or PBS, which were intragastrically administered once per day for 3 days. Nine gerbils died during the study course. On day 10 postinfection, gerbils were euthanized and trophozoites were quantified. Yucca extracts reduced, albeit not significantly, the trophozoite counts in the duodenum segment. Only the high-extract concentration significantly reduced the trophozoite counts in the proximal segment and it was similar to that of metronidazole. Extracts of Y. baccata may represent an effective and natural therapeutic alternative for human giardiosis. PMID:25250335
Fasihi Harandi, Majid; Madjdzadeh, Seyed Massoud; Ahmadinejad, Mohammad
Fifty-one specimens of small mammals were collected from different locations of Kerman province, southeastern Iran during 2007 and 2009. They constitute six species of rodents (Meriones persicus, Meriones libycus, Tatera indica, Dryomys nitedula and Mus musculus), one species of Erinaceomorpha (Paraechinus hypomelas) and one species of hare (Lepus europeus). The rate of helminthic infection was 45.1 % among all trapped specimens. In 28 out of 51 hunted specimens no intestinal helminth parasite was found. Of all mammals examined, 15 (29.4 %) had nematodes, 5 (9.8 %) had cestodes, and 3 (5.9 %) were infected with Acanthocephala. Five different species of parasites were isolated: Trichuris muris, Moniliformis moniliformis, Hymenolepis diminuta, Hymenolepis nana, and Mastophorus muris. Results of the present study indicate the potential of small mammals in the transmission of zoonotic helminthic infection.
Nateghpour, Mehdi; Motevalli-Haghi, Afsaneh; Akbarzadeh, Kamran; Akhavan, Amir Ahmad; Mohebali, Mehdi; Mobedi, Iraj; Farivar, Leila
Background: This study was aimed to collect wild rodents for endoparasites determination in some parts of Sistan and Baluchistan Province, southeastern Iran nearby Pakistan and Afghanistan countries. Methods: A total of 100 wild rodents were captured alive with cage traps. Various samples were collected from blood and feces, also impression smear prepared from different organs. The samples were prepared by formalin-ether or stained with Giemsa, after that were examined under microscope. Results: All the caught rodents (47 Tatera indica, 44 Meriones hurriana, 5 Gerbilus nanus and 4 Meriones libycus) were studied for endoparasites emphasizing to their zoonotic aspects. Endoparasites including Spirurida, Hymenolepis diminuta, Hymenolepis nana feraterna, Trichuris trichiura, Skerjabino taenia, Trichostrongylus spp, Entamoeba muris, Chilomastix mesnili and Leishmania spp were parasitologically identified. Conclusion: Among 9 genera or species of the identified parasites at least 5 of them have zoonotic and public health importance. PMID:26114139
Yoon, Y.; Kim, N.; Puria, S.; Steele, C. R.
In this work, basilar membrane velocity (VBM), scala tympani intracochlear pressure (PST), and cochlear input impedances (Zc) for gerbil and chinchilla are implemented using a three-dimensional hydro-dynamic cochlear model using 1) time-averaged Lagrangian, 2) push-pull mechanism in active case, and 3) the complex anatomy of cochlear scalae by micro computed tomography (μCT) scanning and 3-D reconstructions of gerbil and chinchilla temporal bones. The objective of this work is to compare the calculations and the physiological measurements of gerbil and chinchilla cochlear such as VBM (Ren and Nuttall ), PST (Olson ), and ZC (Decraemer et al. , Songer and Rosowski , Ruggero et al. ) with present model. A WKB asymptotic method combined with Fourier series expansions is used to provide an efficient simulation. VBM and PST simulation results for the gerbil cochlea show good agreement both in the magnitude and the phase for the physiological measurements without larger phase excursion. ZC simulation from the gerbil and chinchilla model show reasonably good agreement with measurement.
Alves Neto, Aldo F; Bandini, Luciana A; Nishi, Sandra M; Soares, Rodrigo M; Driemeier, David; Antoniassi, Nadia A B; Schares, Gereon; Gennari, Solange M
The aim of the present study was to evaluate the viability of Neospora caninum sporulated oocysts after various chemical and physical treatments. Bioassays in gerbils and molecular techniques (PCR-RFLP) were used for identification of the oocysts shed by experimentally infected dogs. Sporulated oocysts were purified and divided into 11 treatment groups as follows: absolute ethanol for 1 hr; 20 C for 6 hr; 4 C for 6 hr; 60 C for 1 min; 100 C for 1 min; 10% formaldehyde for 1 hr; 10% ammonia for 1 hr; 2% iodine for 1 hr; 10% sodium hypochlorite for 1 hr; 70% ethanol for 1 hr; and one group was left untreated and kept as a positive control. All chemical treatments were performed at room temperature (37 C). A total of 33 gerbils, or 3 gerbils per treatment, were used for bioassays. After treatment, the oocysts were divided into aliquots of 1,000 oocysts and orally administered to gerbils. After 63 days, the gerbils were anesthetized and killed with 0.2 ml of T61; blood and tissue samples were collected for serological (IFAT and western blotting), molecular (real-time PCR), histopathology, and immunohistochemical tests. Treatments were considered effective only if all 5 detection techniques tested negative. High temperatures at 100 C for 1 min and 10% sodium hypochlorite for 1 hr were the only treatments that met this condition, effectively inactivating all oocysts.
Samy, Abdallah M; Annajar, Badereddin B; Dokhan, Mostafa Ramadhan; Boussaa, Samia; Peterson, A Townsend
Cutaneous leishmaniasis ranks among the tropical diseases least known and most neglected in Libya. World Health Organization reports recognized associations of Phlebotomus papatasi, Psammomys obesus, and Meriones spp., with transmission of zoonotic cutaneous leishmaniasis (ZCL; caused by Leishmania major) across Libya. Here, we map risk of ZCL infection based on occurrence records of L. major, P. papatasi, and four potential animal reservoirs (Meriones libycus, Meriones shawi, Psammomys obesus, and Gerbillus gerbillus). Ecological niche models identified limited risk areas for ZCL across the northern coast of the country; most species associated with ZCL transmission were confined to this same region, but some had ranges extending to central Libya. All ENM predictions were significant based on partial ROC tests. As a further evaluation of L. major ENM predictions, we compared predictions with 98 additional independent records provided by the Libyan National Centre for Disease Control (NCDC); all of these records fell inside the belt predicted as suitable for ZCL. We tested ecological niche similarity among vector, parasite, and reservoir species and could not reject any null hypotheses of niche similarity. Finally, we tested among possible combinations of vector and reservoir that could predict all recent human ZCL cases reported by NCDC; only three combinations could anticipate the distribution of human cases across the country.
Samy, Abdallah M.; Annajar, Badereddin B.; Dokhan, Mostafa Ramadhan; Boussaa, Samia; Peterson, A. Townsend
Abstract Cutaneous leishmaniasis ranks among the tropical diseases least known and most neglected in Libya. World Health Organization reports recognized associations of Phlebotomus papatasi, Psammomys obesus, and Meriones spp., with transmission of zoonotic cutaneous leishmaniasis (ZCL; caused by Leishmania major) across Libya. Here, we map risk of ZCL infection based on occurrence records of L. major, P. papatasi, and four potential animal reservoirs (Meriones libycus, Meriones shawi, Psammomys obesus, and Gerbillus gerbillus). Ecological niche models identified limited risk areas for ZCL across the northern coast of the country; most species associated with ZCL transmission were confined to this same region, but some had ranges extending to central Libya. All ENM predictions were significant based on partial ROC tests. As a further evaluation of L. major ENM predictions, we compared predictions with 98 additional independent records provided by the Libyan National Centre for Disease Control (NCDC); all of these records fell inside the belt predicted as suitable for ZCL. We tested ecological niche similarity among vector, parasite, and reservoir species and could not reject any null hypotheses of niche similarity. Finally, we tested among possible combinations of vector and reservoir that could predict all recent human ZCL cases reported by NCDC; only three combinations could anticipate the distribution of human cases across the country. PMID:26863317
Ma, Libin; Gorochov, Andrej V; Zhang, Yalin
A bark cricket genus Duolandrevus Kirby, 1906 is discussed here. These species are brownish with depressed bodies, with reduced elytra, lack hind wings and live in the bark of dead trees or branches. Duolandrevus are distributed from the south of China and Japan to the Philippines, the Malay Archipelago and New Guinea. Only one species, Duolandrevus hongkongae Otte, 1988, was recorded in China. Here, one additional species, Duolandrevus (Eulandrevus) unguiculatus sp. nov. is described from Southern China. Its description and illustrations and the key to the subgenera of Duolandrevus worldwide are given.
Zubova, O A; Guliaev, V D; Kornienko, S A
A new species Soricinia sawadai sp. n. parasitizing shrews of Sakhalin Island (Sores unguiculatus and S. caecutiens) is described. The new species differs from other species of the genus Soricinia Spassky et Spasskaja, 1954 in having specific armament and size of the cirrus. Soricinia sawadai sp. n. differs from S. aurita (Irzhavsky et al., 2005) in having half size of the ovary (0.076-0.08 x 0.03-0.038 versus 0.135-0.14 x 0.037-0.04) and the cirrus bursa extending into the aporal fraction of the middle part of segment. The new species differs from S. quarta (Karpenko, 1983) in having half size of the cirrus (0.025-0.026 versus 0.05-0.055) and half number of hexacants in uterine segments (20-22 versus 40-45). The new species differs from S. infirma (Zarnowski, 1955) in having other cirrus armament, larger number of segments and lesser number of hexacants. The species Insectivorolepis macracetobulosa Sawada et Koyasu, 1991 parasitizing Sorex unguiculatus on Hokkaido Island is synonymized with Soricinia quarta. The species Insectivorolepis macracetobulosa sensu Sawada et Harada, 1993 parasitizing Sorex shinto shinto on Honshu Island is described as a separate species Soricinia haradai sp. n.
Greening, Gary A.
Presented are science units for kindergarten and first-grade classes which include one or more non-verbal test items constructed to determine whether the student has learned the material presented in the unit. Units include: light, senses, gerbils, beans and peas, animal activities, and hatching chicks. (SL)
Agro, Sally; And Others
In this set of two booklets for primary grades, students learn how to make a home for their animals (amphibians, insects, fish, crayfish) and a home for their rodents (hamsters, guinea pigs, gerbils, mice). The major emphasis in all Unified Sciences and Mathematics for Elementary Schools (USMES) units is on open-ended, long-range investigations of…
Vansant, Rhonda; Dondiego, Barbara L.
Studying pets fosters children's natural curiosity about the world around them and encourages them to use their five senses. This cross-curricular guide provides opportunities for children to build concepts by introducing them to a variety of household pets beginning with cats and dogs, and including mice, gerbils, hamsters, rabbits, guinea pigs,…
Texas Child Care, 1994
Notes that rodents and rabbits share many characteristics that make them suitable classroom pets and gives background information on rabbits, guinea pigs, hamsters, and gerbils. Offers advice on buying a classroom pet, the pet's home, feeding, helping the children handle the pet, and pet health and family planning. (TJQ)
National Academy of Sciences - National Research Council, Washington, DC. Board on Agricultural and Renewable Resources.
This report deals with the nutrient requirements of seven species of animals used extensively for biomedical research in the United States. Following an introductory chapter of general information on nutrition, chapters are presented on the nutrient requirements of the laboratory rat, mouse, gerbil, guinea pig, hamster, vole, and fishes. Each…
Nottingham, Theodore J.
This book of fables from the animal kingdom contains: "The Frog Who Knew Too Much"; "Long Tail the Lizard"; "The Otter Who Went to the Bottom of the Sea"; "The Single-Wattled Cassowary and His Lethal Toe"; "The Rebel Gerbil"; "Why Hairless Monkeys Turn Out So Bad"; and "The Eagles'…
McLaughlin, Alicia; Strunk, Anneliese
Small exotic mammal pets such as rats, mice, hamsters, gerbils, degus, hedgehogs, and sugar gliders are becoming more popular. Because these animals are prone to a variety of health problems, and require specialized husbandry care to remain healthy, they may present to emergency hospitals in critical condition. This article provides a basic overview of common emergency presentations of these species.
Hendon, David H.; Barlow, Judith L.
Presents (with tongue in cheek) a four-style behavior model guaranteed to produce excellence in the four types of trainees: nematodes (docile but learn nothing), gerbils (fond of noncompetitive games and hugging), warthogs (like to attend expensive seminars), and Cro-Magnon (like to interpret to others as opposed to actually learning anything…
Musacchia, X. J.
Studies are presented of the physiology of depressed metabolism, radio-resistance in depressed metabolic states, comparative aspects of depressed metabolism, and gastrointestinal responses to ionizing radiation. Specific data cover helium-cold induced hypothermia in white rats and hamsters, and radiation responses and intestinal absorption in the gerbil.
Hood, J D; Banks, R M; Brewer, M D; Fish, J P; Manger, B R; Poulton, M E
A novel series of milbemycin antibiotics were produced by soil isolate, strain E225 which was shown to be a Streptomyces species. The antibiotics displayed anthelmintic activity against Trichostrongylus colubriformis in the gerbil. Two of the compounds, VM 44857 and VM 44866 were shown to be potent anthelmintics against mixed nematode infections in sheep.
Bakhshi, Hasan; Oshaghi, Mohammad Ali; Abai, Mohammad Reza; Rassi, Yavar; Akhavan, Amir Ahmad; Mohebali, Mehdi; Hajaran, Homa; Mohtarami, Fatemeh; Mirzajani, Hossein; Maleki-Ravasan, Naseh
Background: Great gerbils, Rhombomys opimus, are the main reservoir host of zoonootic cutaneous leishmaniasis (ZCL) in Iran and neighboring countries. Based on morphological traits two subspecies R. opimus sodalis and R. opimus sargadensis have reported in the country. However, variation in infection rate and signs to Leishmania parasites, phenotype, size, and sexual polymorphisms demand more details to elucidate clearly the role of great gerbils in ZCL epidemiology. Methods: PCR-RFLP and PCR-direct sequencing were used to analyze mitochondrial DNA cytochrome B (mtDNA-cytB) gene structure of R. opimus collected from Golestan and Khorasan-e-Razavi Provinces in 2011 that are neighbor to Turkmenistan Country where ZCL is endemic in both sides of the borderline. Results: All of the specimens (n= 61) were morphologically or genetically similar to the typical R. opimus sodalis. However, there were 9 (1.5%) DNA substitutions throughout the 583 bp of the Cyt b gene of the samples sequenced comprising six DNA haplotypes. Maximum likelihood or neighbor joining phylogenetic trees inferred from the sequences could resolve the populations according to their subspecies as well as geographical origins. Discussion: The DNA polymorphisms in the great gerbils may correspond to the signs and infection rate in the animal. However, further studies are needed to match these six haplotypes with different signs and parasite sustaining following infection with L. major in the great gerbils. PMID:24409443
This resource book presents 37 behavioral experiments that can be performed with commonly-found classroom animals including hamsters, gerbils, mice, goldfish, guppies, anolis lizards, kittens, and puppies. Each experiment explores the five steps of the scientific method: (1) Question; (2) Hypothesis; (3) Methods; (4) Result; and (5) Conclusion.…
... considered retail pet stores: Dogs, cats, rabbits, guinea pigs, hamsters, gerbils, rats, mice, gophers... or purchase of any animal, except wild or exotic animals, dogs, or cats, and who derives no more than... three to four the number of breeding female dogs, cats, and/or small exotic or wild mammals that...
... the number of breeding female dogs, cats, and/or small exotic or wild mammals that a person may... as pets are considered retail pet stores: Dogs, cats, rabbits, guinea pigs, hamsters, gerbils, rats..., dogs, or cats, and who derives no more than $500 gross income from the sale of such animals....
OFFICE CAMPUS * MERION TOWLE HOUSE OBWL DELL, PA. 19422 21.542--400 Si UnclIasqi f iPed SECURITYCA4FICATION OF THIS PAGE ("o Dcive Entered) 2. GVT...and the direction in which the delamination propagates is governed by the least of the three P cr values. Finite Element Analysis of a Delaminated Beam...process or a service defect that is a result of cyclic loading, impact, etc. Considering a typical practicalI application to be an aircraft wing, the
Radice, A. D.; Myers, R. F.; Halisky, P. M.
Punctodera punctata completed its life cycle on Poa annua (annual bluegrass), P. pratensis (Merion Kentucky bluegrass), Lolium perenne (perennial ryegrass), and Festuca rubra rubra (spreading fescue). Minimum time for completion of a life cycle from second-stage juvenile to mature brown cyst was 40 days at 22-28 C. Inoculation by single juveniles indicated that reproduction was most likely by amphimixis. Infestation levels of 50 or 500 juveniles/250 cm³ soil did not affect top dry weight, root dry weight, or total dry weight of Poa annua. PMID:19294077
Jeffrey, Amy; Denys, Christiane; Stoetzel, Emmanuelle; Lee-Thorp, Julia A.
The stable isotope composition of small mammal tissues has the potential to provide detailed information about terrestrial palaeoclimate and environments, because their remains are abundant in palaeontological and archaeological sites, and they have restricted home ranges. Applications to the Quaternary record, however, have been sparse and limited by an acute lack of understanding of small mammal isotope ecology, particularly in arid and semi-arid environments. Here we document the oxygen and carbon isotope composition of Gerbillinae (gerbil) tooth apatite across a rainfall gradient in northwestern Africa, in order to test the relative influences of the 18O/16O in precipitation or moisture availability on gerbil teeth values, the sensitivity of tooth apatite 13C/12C to plant responses to moisture availability, and the influence of developmental period on the isotopic composition of gerbil molars and incisors. The results show that the isotopic composition of molars and incisors from the same individuals differs consistent with the different temporal periods reflected by the teeth; molar teeth are permanently rooted and form around the time of birth, whereas incisors grow continuously. The results indicate that tooth choice is an important consideration for applications as proxy Quaternary records, but also highlights a new potential means to distinguish seasonal contexts. The oxygen isotope composition of gerbil tooth apatite is strongly correlated with mean annual precipitation (MAP) below 600 mm, but above 600 mm the teeth reflect the oxygen isotope composition of local meteoric water instead. Predictably, the carbon isotope composition of the gerbil teeth reflected C3 and C4 dietary inputs, however arid and mesic sites could not be distinguished because of the high variability displayed in the carbon isotope composition of the teeth due to the microhabitat and short temporal period reflected by the gerbil. We show that the oxygen isotope composition of small
Shepherd, A. J.; Leman, P. A.; Hummitzsch, D. E.
Susceptibility studies were undertaken to determine the response of some South African wild rodent species to experimental plague (Yersinia pestis) infection. A degree of plague resistance was found in three gerbil species captured in the plague enzootic region of the northern Cape Province, these being the Namaqua gerbil, Desmodillus auricularis, (LD50 1 X 10(6) organisms), the bushveld gerbil, Tatera leucogaster, (LD50 9.1 X 10(5)) and the highveld gerbil, T. brantsii (LD50 4 X 10(2)). Animals from a population of the four-striped mouse, Rhabdomys pumilio, captured in the plague area of Port Elizabeth, proved moderately resistant to experimental plague infection (LD50 1.3 X 10(4)) while those from another population of the same species captured in a plague-free area of the Orange Free State were extremely susceptible (LD50, 5 organisms). The response of both populations however was a heterogeneous one. Marked differences in susceptibility were also found between two populations of multimammate mice, Mastomys natalensis (2n = 32) although both originated from areas outwith the known distribution of plague in southern Africa. The 50% infectious dose was relatively high in T. leucogaster (3.2 X 10(2)) and D. auricularis (1.7 X 10(3)), but was low (2-16 organisms) in the other rodent species tested. The plague antibody response, determined by enzyme-linked immunosorbent assay (ELISA), was extremely short-lived in T. leucogaster, only 10% of inoculated animals remaining seropositive at low titres after 11 weeks. Antibodies persisted for only slightly longer in the sera of T. brantsii which were reinoculated with 2 X 10(3) plague organisms 6 weeks after initial challenge. The demonstration of the existence of both susceptible and resistant populations of R. pumilio and M. natalensis indicates that these species must be considered as potential plague reservoir hosts in parts of South Africa. The results suggest that resistance to plague infection in previously epizootic
Nateghpour, M; Akhavan, A A; Hanafi-Bojd, A A; Telmadarraiy, Z; Ayazian Mavi, S; Hosseini-Vasoukolaei, N; Motevalli-Haghi, A; Akbarzadeh, K
During 2008-2009 a total of 67 individuals of rodents, Tetera indica, Meriones hurrianae, Meriones libycus and Gerbillus nanus were trapped in three areas, Bampor, Daman and Qasre Qand from Iranshahr and Nikshahr districts. There is a significant difference between comparative abundance of four species (P<0.05). A total of 1422 ectoparasites collected including 299 mites (21%), 127 fleas (8.9%), 972 lice (68.4%) and 24 ticks (1.7%). Significant findings amongst the ectoparasites is the lice group with three species identified, Laelaps accuninata, Andralaelaps hermophrodita and Paracheylaellaps pyriformis being the first record in the study areas. All four captured genera of rodents are known as main/ potential reservoir hosts of zoonotic cutaneous leishmaniasis. The migration habit of rodents may affect the spatial distribution of parasitic ticks and their transmitted diseases like CCHF, which has been reported in recent years from Sistan and Baluchestan province. Monitoring of rodent populations and their ectoparasites will help to predict the potential of zoonotic arthropod-borne diseases.
Xu, Wanlong; Zhao, Xibin; Wang, Qing; Sun, Jungang; Xu, Jiangbo; Zhou, Wenzheng; Wang, Hao; Yan, Shigui; Yuan, Hong
During radiotherapy to kill femoral hydatid tapeworms, the sciatic nerve surrounding the focus can be easily damaged by the treatment. Thus, it is very important to evaluate the effects of radiotherapy on the surrounding nervous tissue. In the present study, we used three-dimensional, conformal, intensity-modulated radiation therapy to treat bilateral femoral hydatid disease in Meriones meridiani. The focus of the hydatid disease on the left femur was subjected to radiotherapy (40 Gy) for 14 days, and the right femur received sham irradiation. Hematoxylin-eosin staining, electron microscopy, and terminal deoxynucleotidyl transferase-dUTP nick end labeling assays on the left femurs showed that the left sciatic nerve cell structure was normal, with no obvious apoptosis after radiation. Trypan blue staining demonstrated that the overall protoscolex structure in bone parasitized with Echinococcus granulosus disappeared in the left femur of the animals after treatment. The mortality of the protoscolex was higher in the left side than in the right side. The succinate dehydrogenase activity in the protoscolex in bone parasitized with Echinococcus granulosus was lower in the left femur than in the right femur. These results suggest that three-dimensional conformal intensity-modulated radiation therapy achieves good therapeutic effects on the secondary bone in hydatid disease in Meriones meridiani without damaging the morphology or function of the sciatic nerve. PMID:25422645
Huang, Ting; Yan, Chaochao; Tan, Zheng; Tu, Feiyun; Yue, Bisong; Zhang, Xiuyue
The elegant water shrew (Nectogale elegans) belongs to the family Soricidae, and distributes in northern South Asia, central and southern China and northern Southeast Asia. In this study, the complete mitochondrial genome of N. elegans was sequenced. It was determined to be 17,460 bases, and included 13 protein-coding genes (PCGs), 22 tRNA genes, 2 ribosomal RNA genes and one non-coding region, which is similar to other mammalian mitochondrial genomes. Bayesian inference and maximum likelihood methods were used to construct phylogenetic trees based on 12 heavy-strand concatenated PCGs. Phylogenetic analyses further confirmed that Crocidurinae diverged prior to Soricinae, and Sorex unguiculatus differentiated earlier than N. elegans.
Nakamura, Ichiro; Hang'ombe, Bernard Mudenda; Sawa, Hirofumi; Kobayashi, Shintaro; Orba, Yasuko; Ishii, Akihiro; Thomas, Yuka; Isozumi, Rie; Yoshimatsu, Kumiko; Mweene, Aaron S; Takada, Ayato; Sugimoto, Chihiro; Arikawa, Jiro
A total of 466 rodents were captured in the Republic of Zambia from 2006 to 2010. Based on morphological observations and phylogenetic analyses of mitochondrial gene sequences, rodents were divided into 10 groups consisting of 39 Rattus rodents, 263 multimammate rats, 18 other Murinae rodents, 95 gerbils, 11 pouched mice, 1 giant-pouched rat, 38 fat mice and 1 dormouse. Rodent antibodies except that from Rattus were examined for their cross-reactivity to commercially available antibody detection reagents. Anti-mouse immunoglobulin G (IgG) was most cross-reactive to heterologous antibodies including multimammate rat, gerbil, pouched mouse and fat mouse. Thus, anti-mouse IgG would be a useful detection tool in serological examination of the Zambian rodent population. Preliminary sero-surveillance for plague, leptospirosis and hantavirus infection was performed by ELISA.
Rivero, Fernando D; Saura, Alicia; Prucca, Cesar G; Carranza, Pedro G; Torri, Alessandro; Lujan, Hugo D
Giardia lamblia is a human intestinal pathogen. Like many protozoan microorganisms, Giardia undergoes antigenic variation, a mechanism assumed to allow parasites to evade the host's immune response, producing chronic and/or recurrent infections. Recently, we found that the mechanism controlling variant-specific surface protein (VSP) switching in Giardia involves components of the RNA interference machinery and that disruption of this pathway generates trophozoites simultaneously expressing many VSPs. Here we use these altered trophozoites to determine the role of antigenic variation in a gerbil model of giardiasis. Our results show that either primary infection with trophozoites simultaneously expressing many VSPs or immunization with purified VSPs from the transgenic cells protects gerbils from subsequent Giardia infections. These results constitute, to our knowledge, the first experimental evidence that antigenic variation is essential for parasite survival within hosts and that artificial disruption of this mechanism might be useful in generating vaccines against major pathogens that show similar behavior.
Nonaka, N; Iwaki, T; Okamoto, M; Ooi, H K; Oku, Y; Ohbayashi, M; Kamiya, M
Taenia taeniaeformis were isolated from Norway rats captured at Sapporo (SRN isolate) and Kuala Lumpur, Malaysia (KRN) and from Bedford's gray red-backed voles at Toubetsu (TCR) and Abuta (ACR). SRN, KRN and TCR isolates showed similar degree of infectivity to various rodents in which cysticerci with hooks were obtained in laboratory rats, white tuberous lesions in mice and no cysts or lesions in Mongolian gerbils and voles. Contrary to this, inoculation with ACR isolate eggs resulted in strobilocerci formation in the liver of voles, but no cysts were observed in rats, mice or gerbils. This host specificity of ACR isolate to voles suggests that it might be a new species of Taenia.
Stenseth, Nils Chr; Samia, Noelle I; Viljugrein, Hildegunn; Kausrud, Kyrre Linné; Begon, Mike; Davis, Stephen; Leirs, Herwig; Dubyanskiy, V M; Esper, Jan; Ageyev, Vladimir S; Klassovskiy, Nikolay L; Pole, Sergey B; Chan, Kung-Sik
The bacterium Yersinia pestis causes bubonic plague. In Central Asia, where human plague is still reported regularly, the bacterium is common in natural populations of great gerbils. By using field data from 1949-1995 and previously undescribed statistical techniques, we show that Y. pestis prevalence in gerbils increases with warmer springs and wetter summers: A 1 degrees C increase in spring is predicted to lead to a >50% increase in prevalence. Climatic conditions favoring plague apparently existed in this region at the onset of the Black Death as well as when the most recent plague pandemic arose in the same region, and they are expected to continue or become more favorable as a result of climate change. Threats of outbreaks may thus be increasing where humans live in close contact with rodents and fleas (or other wildlife) harboring endemic plague.
Von Lubitz, D K; Lin, R C; McKenzie, R J; Devlin, T M; McCabe, R T; Skolnick, P
Chronic treatment of gerbils with 1-aminocyclopropanecarboxylic acid (a high affinity, partial agonist at strychnine-insensitive glycine receptors) resulted in a 3-fold increase in survival, a significant improvement in neurological status, and an extensive protection of vulnerable brain regions following severe forebrain ischaemia. A bolus of 1-aminocyclopropanecarboxylic acid 30 min prior to ischaemia did not further improve outcome compared to gerbils receiving their last injection 24 h prior to ischaemia. These findings are consistent with the hypothesis that chronic treatment with a glycine partial agonist desensitizes the N-methyl-D-aspartate receptor complex. Pharmacological intervention at the strychnine-insensitive glycine receptor may be an effective means of ameliorating the consequences of neuronal degeneration caused by excitotoxic phenomena.
Lossi, Laura; D'Angelo, Livia; De Girolamo, Paolo; Merighi, Adalberto
The anatomical features distinctive to each of the very large array of species used in today's biomedical research must be born in mind when considering the correct choice of animal model(s), particularly when translational research is concerned. In this paper we take into consideration and discuss the most important anatomical and histological features of the commonest species of laboratory rodents (rat, mouse, guinea pig, hamster, and gerbil), rabbit, and pig related to their importance for applied research.
Levy, D E; Zwies, A; Duffy, T E
A mask was developed for the administration of volatile anesthetics and other gases to small, spontaneously breathing laboratory animals. A vacuum-powered venting system surrounding the inspiratory gas supply prevented potentially hazardous gases from escaping into the environment. This system was used to deliver nitrous oxide, halothane, and methoxyflurane to rats, gerbils, and newborn dogs. It was used to vary the oxygen and carbon dioxide concentrations inspired by spontaneously breathing animals undergoing physiological experiments.
Satoh, Kunio; Niwa, Masayuki; Binh, Nguyen Huy; Nakashima, Masaya; Kobayashi, Kazuhiro; Takamatsu, Manabu; Hara, Akira
The ischemic damage in the hippocampal CA1 region following transient forebrain ischemia, delayed neuronal death, is a typical apoptotic response, but the underlying mechanisms are not fully understood. We have reported that mild hyperthermia (38 °C) accelerates DNA fragmentation of the gerbil CA1 pyramidal neurons following transient forebrain ischemia. Recently, we reported that galectin-3, a β-galactosidase-binding lectin, is spatio-temporally expressed only by activated microglial cells located within CA1 region following transient forebrain ischemia in gerbils. Furthermore, expression of galectin-3 and Iba-1 (a specific microglial cell marker) are strongly reduced by hypothermia during ischemic insult. To further elucidate the effect of hyperthermia on the expression of galectin-3 by micloglia in delayed neuronal death, we examined immunohistochemical expression of galectin-3 and Iba-1, in situ terminal dUTP-biotin nick end labeling of DNA fragmentation (for determination of cell death) and hematoxylin and eosin staining (for morphological observation). We observed that between 37 °C and 39 °C, there was a temperature-dependent enhancement of galectin-3 expression in microglial cells in the CA1 region following transient ischemia. Apoptotic DNA fragmentation, detected by TUNEL staining, was observed in CA1 region in normothermia. This TUNEL staining was enhanced by hyperthermia at 37.5 °C and 38 °C, but not at 39 °C. Ischemia-induced neuronal degeneration in CA1 region in gerbil hippocampus subjected to hyperthermia (37.5 °C, 38 °C and 39 °C) observed by HE staining is similar to that in normothermic gerbils. These findings imply that galectin-3 expression in microglia may influence the survival of CA1 pyramidal neurons in cases such as hyperthermia-related neuronal injury.
Correia, Manning J.; TABARACCI
The general goal was to examine tilt sensitivity of horizontal semicircular canal afferents. Computer programs were tested which controlled the short axis centrifuge at the Vestibular Research Facility, acquired action potentials and produced data reduction analyses including histograms and gain and phase calculations. A pre-amplifier was also developed for the acquisition of action potentials. The data were gathered that can be used to contribute toward the understanding of the tilt sensitivity of semicircular canal afferents in the unanesthetized gerbil preparation.
Strelkova, M V; Shendrik, A G; El Fari, M; Schonian, G
A PCR fingerprinting approach with single non-specific primers--(GTG)5 and T3B--was apply to investigate variations in the genotyping of three species of Leishmania species within the Rhombomys opimus area. Forty-three strains of Leishmania major, L. turanica, and L. gerbilli circulating among great gerbils in Turkmenistan, Uzbekistan, Kazakhstan, and Mongolia were examined. PCR fingerprint revealed a high genetic intraspecific heterogeneity among L. turanica strains. Three groups of strains were clearly identified. The strains from Mongolia greatly differed from other L. turanica ones. The second group was formed by strains from Kazakhstan, they also demonstrated rather different patterns. L. turanica strains from Turkmenistan and Uzbekistan showed only minor differences, but greatly different from those from Kazakhstan and Mongolia. The groups identified by the PCR fingerprint correlate with the conditions of circulation: the duration of a transmission season and as the result of different periods of retention of Leishmania in the skin of great gerbils, as well as the presence or absence of L. major as coexisting species. There were no differences between L. turanica strains isolated from different hosts in the same geographical region, as well as between L. turanica strains isolated in the hyper- or meso and hypoendemic foci. There was no correlation between the genotypic and phenotypic characteristics of L. turanica. No intraspecific polymorphism was found among L. major and L. gerbilli strains from different geographical regions within the great gerbil area.
Gutman, Roee; Choshniak, Itzhak; Kronfeld-Schor, Noga
Golden spiny mice, which inhabit rocky deserts and do not store food, must therefore employ physiological means to cope with periods of food shortage. Here we studied the physiological means used by golden spiny mice for conserving energy during food restriction and refeeding and the mechanism by which food consumption may influence thermoregulatory mechanisms and metabolic rate. As comparison, we studied the response to food restriction of another rocky desert rodent, Wagner's gerbil, which accumulates large seed caches. Ten out of 12 food-restricted spiny mice (resistant) were able to defend their body mass after an initial decrease, as opposed to Wagner's gerbils (n = 6). Two of the spiny mice (nonresistant) kept losing weight, and their food restriction was halted. In four resistant and two nonresistant spiny mice, we measured heart rate, body temperature, and oxygen consumption during food restriction. The resistant spiny mice significantly (P < 0.05) reduced energy expenditure and entered daily torpor. The nonresistant spiny mice did not reduce their energy expenditure. The gerbils' response to food restriction was similar to that of the nonresistant spiny mice. Resistant spiny mice leptin levels dropped significantly (n = 6, P < 0.05) after 24 h of food restriction, and continued to decrease throughout food restriction, as did body fat. During refeeding, although the golden spiny mice gained fat, leptin levels were not correlated with body mass (r(2) = 0.014). It is possible that this low correlation allows them to continue eating and accumulate fat when food is plentiful.
Kim, Namkeun; Yoon, Yongjin; Steele, Charles; Puria, Sunil
A novel micro computed tomography (μCT) image processing method was implemented to measure anatomical features of the gerbil and chinchilla cochleas, taking into account the bent modailosis axis. Measurements were made of the scala vestibule (SV) area, the scala tympani (SV) area, and the basilar membrane (BM) width using prepared cadaveric temporal bones. 3-D cochlear structures were obtained from the scanned images using a process described in this study. It was necessary to consider the sharp curvature of mododailosis axis near the basal region. The SV and ST areas were calculated from the μCT reconstructions and compared with existing data obtained by Magnetic Resonance Microscopy (MRM), showing both qualitative and quantitative agreement. In addition to this, the width of the BM, which is the distance between the primary and secondary osseous spiral laminae, is calculated for the two animals and compared with previous data from the MRM method. For the gerbil cochlea, which does not have much cartilage in the osseous spiral lamina, the μCT-based BM width measurements show good agreement with previous data. The chinchilla BM, which contains more cartilage in the osseous spiral lamina than the gerbil, shows a large difference in the BM widths between the μCT and MRM methods. The SV area, ST area, and BM width measurements from this study can be used in building an anatomically based mathematical cochlear model.
Avila, Guillermina; Teran, Nancy; Aguilar-Vega, Laura; Maravilla, Pablo; Mata-Miranda, Pilar; Flisser, Ana
Human beings are the only hosts of adult Taenia solium; thus, many aspects of the host-parasite relationship are unknown. The development of successful experimental models of taeniasis allows in-depth investigations of the host-parasite relationship. We established experimental models in hamsters, gerbils and chinchillas. Here we review our findings regarding the characteristics of the tapeworms, their anchoring site and development, as well as the humoral and cellular immune response they elicit. We also used statistics to analyze the data obtained in different infections performed along several years. Furthermore, we compared the size of T. solium rostellum and strobila recovered from hamsters and gerbils to those obtained from humans. Our data indicate that these rodents are adequate experimental models for studying T. solium in its adult stage; that parasites induce immune responses and that hamsters seem to be more permissive hosts than gerbils, since parasites survive for longer times, grow longer and develop more, and the inflammatory response in the intestinal mucosa against T. solium is moderate. Finally, chinchillas are the most successful experimental definitive model for adult T. solium, since tapeworms with gravid proglottids are obtained, and the life cycle can be continued to the intermediate host.
Dubey, J P; Sreekumar, C; Lindsay, D S; Hill, D; Rosenthal, B M; Venturini, L; Venturini, M C; Greiner, E C
A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits, outbred Swiss Webster and interferon gamma gene knockout mice. Bradyzoites were infective orally to gerbils and cats. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells. Schizonts were seen in the lamina propria of the small intestine of cats fed tissue cysts; the largest ones measured 52 x 45 microm. Schizonts were also present in mesenteric lymph nodes, livers, and other extra-intestinal organs of cats fed tissue cysts. Oocysts were 10-14 x 10-13 microm in size. This rabbit-derived species of Besnoitia resembled B. darlingi of the North American opossum, Didelphis virginiana with an opossum-cat cycle, but it was not transmissible to D. virginiana, and B. darlingi of opossums was not transmissible to rabbits. Based on biological, serological, antigenic, and molecular differences between the rabbit and the opossum Besnoitia, a new name, B. oryctofelisi is proposed for the parasite from domestic rabbits from Argentina.
Saidi, S; Tesh, R; Javadian, E; Sahabi, Z; Nadim, A
Human and animal sera from an endemic area of sandfly fever in Iran were tested by plaque reduction neutralization method against five different Phlebotomus fever virus serotypes (Naples, Sicilian, Karimabad, Salehabad, and I-47). The overall prevalence of Naples, Sicilian, and Karimabad virus antibodies among the human population was 17%, 25%, and 66%, respectively. All sera were negative against Salehabad and I-47 viruses. Age-specific antibody rates suggested that Sicilian and Karimabad viruses were endemic in the study area but that Naples virus activity was sporadic. These observations were confirmed by isolations of Sicilian and Karimabad viruses from sandflies collected in the study area. Among the animal sera tested, evidence of Phlebotomus fever virus infection was detected only in gerbils. Of 38 Rhombomys opimus tested, 34% had neutralizing antibodies against Sicilian virus and 32% against Karimabad. These results indicate that gerbils are infected with these two viruses and possibly might serve as reservoirs or amplifying hosts. The serologic studies also suggest that the ecology of Sicilian and Karimabad viruses involves chiefly sandflies, gerbils, and man, an epidemiologic pattern previously demonstrated for cutaneous leishmaniasis in the same region of Iran.
Zarrintab, Mohammad; Mirzaei, Rouhollah
In the present study, the effects of sex, age, nutritional status, and habitat use on hair and internal tissue concentrations of some trace metals (Zn, Cu, Ni, Pb and Cd) in brown rat (Rattus norvegicus) and great gerbil (Rhombomys opimus) from Aran-O-Bidgol City in Central Iran were investigated. Five sampling stations in different land-uses were selected for the study. Concentrations of Cd and Pb in liver and whole body concentration as well as concentration of Zn in hair of male rats were significantly higher than females. A significantly higher concentration was only observed for Pb in kidney of male gerbils than females. In numerous cases, age had significantly negative correlations with concentration of metals in different tissues of both species, and was only significantly (and positively) correlated with the concentration of Cd in kidney and Zn in liver of gerbils. This finding may indicate that the early neonatal age is a critical period for metals accumulation. The relationships between nutritional status and metal concentrations for both species were negative, which can be ascribed to the weight-specific metabolic rate that cause to a relatively low uptake of metals per unit of body weight. No significant differences were observed for soil metals concentrations in different sites. So, this suggests that the influence of life history, microhabitat use and foraging behavior did significantly influence on inter and intra specific variation of metals concentration in small mammals. Our observations suggest that hair cannot be used alone for monitoring exposure of metals.
Chen, Yi-Wen; Sanes, Dan H.
Hearing-impaired individuals experience difficulties in detecting or understanding speech, especially in background sounds within the same frequency range. However, normally hearing (NH) human listeners experience less difficulty detecting a target tone in background noise when the envelope of that noise is temporally gated (modulated) than when that envelope is flat across time (unmodulated). This perceptual benefit is called modulation masking release (MMR). When flanking masker energy is added well outside the frequency band of the target, and comodulated with the original modulated masker, detection thresholds improve further (MMR+). In contrast, if the flanking masker is antimodulated with the original masker, thresholds worsen (MMR−). These interactions across disparate frequency ranges are thought to require central nervous system (CNS) processing. Therefore, we explored the effect of developmental conductive hearing loss (CHL) in gerbils on MMR characteristics, as a test for putative CNS mechanisms. The detection thresholds of NH gerbils were lower in modulated noise, when compared with unmodulated noise. The addition of a comodulated flanker further improved performance, whereas an antimodulated flanker worsened performance. However, for CHL-reared gerbils, all three forms of masking release were reduced when compared with NH animals. These results suggest that developmental CHL impairs both within- and across-frequency processing and provide behavioral evidence that CNS mechanisms are affected by a peripheral hearing impairment. PMID:28215119
Shepherd, A J; Leman, P A; Swanepoel, R
Eleven species of small African wild mammals, laboratory rabbits, guinea pigs, and Syrian hamsters were infected with Crimean-Congo hemorrhagic fever (CCHF) virus. Low-titered viremia followed by development of antibody was observed in scrub hares (Lepus saxatilis), Cape ground squirrels (Xerus inauris), red veld rats (Aethomys chrysophilus), white tailed rats (Mystromys albicaudatus), bushveld gerbils (Tatera leucogaster), striped mice (Rhabdomys pumilio), and guinea pigs. The maximum viremic titer in 4 scrub hares was 10(1.7-4.2) 50% mouse lethal doses/ml. Viremia was detected in 1/17 infected laboratory rabbits. Antibody response was only detected in South African hedgehogs (Atelerix frontalis), highveld gerbils (T. brantsii), Namaqua gerbils (Desmodillus auricularis), 2 species of multimammate mouse (Mastomys natalensis and M. coucha), and Syrian hamsters. The results of the study indicate that a proportion of infected scrub hares develop CCHF viremia of an intensity shown in the Soviet Union to be sufficient for infection of feeding immature ixodid ticks, but that South African hedgehogs and wild rodents are unlikely to be of importance as maintenance hosts of the virus in southern Africa.
Walters, Jacklynn; Marais, Sumine; Johnson, Olga; Bennett, Nigel C; Alagaili, Abdulaziz N; Mohammed, Osama B; Kotzé, Sanet H
Meriones rex (King jird), Meriones libycus (Libyan jird), Acomys dimidiatus (Eastern spiny mouse), Acomys cahirinus (Egyptian spiny mouse), and Dipodillus dasyurus (Wagner's dipodil) are five species of small rodents of the superfamily Muroidea with distributions in Eastern Africa, Egypt, and the desert regions of the Arabian Peninsula. Water is scarce in these regions and may result in relatively low-digestible food. The aim of the present study is to describe and compare the gastrointestinal tract morphology and morphometry of these five species in order to elucidate whether morphology is influenced by phylogeny or dietary preference. Each segment of the gastrointestinal tract of each species was macroscopically examined and the length and basal surface area of each segment was measured. Standard histologic procedures were performed to determine a surface enlargement factor to determine the mucosal luminal surface area. A unilocular-hemiglandular stomach was observed in all the species examined. The caeca of all the species were long and arranged into a loose spiral toward the caecal tip with the ileocaecal and caeco-colic openings positioned close together. Two rows of oblique folds could be observed in the proximal colon of all species except in D. dasyurus which had longitudinal folds. Morphometric analysis showed the largest stomach in A. cahirinus and the largest caecum and colon in M. libycus. All the species can be grouped in the family Muridae in two subfamilies and similarities were observed including the hemiglandular stomach and relatively large caecum. It could be concluded that phylogeny plays an important role in determining gastrointestinal morphology while diet plays a subordinate role in the desert rodents in the present study.
Min, Dongyu; Guo, Feng; Zhu, Shu; Xu, Xiaoxue; Mao, Xiaoyuan; Cao, Yonggang; Lv, Xintong; Gao, Qinghua; Wang, Lei; Chen, Tianbao; Shaw, Chris; Hao, Liying; Cai, Jiqun
The two critical forms of dementia are Alzheimer's disease (AD) and vascular dementia (VD). The alterations of Ca(2+)/calmodulin/CaMKII/CaV1.2 signaling in AD and VD have not been well elucidated. Here we have demonstrated changes in the levels of CaV1.2, calmodulin, p-CaMKII, p-CREB and BDNF proteins by Western blot analysis and the co-localization of p-CaMKII/CaV1.2 by double-labeling immunofluorescence in the hippocampus of APP/PS1 mice and VD gerbils. Additionally, expression of these proteins and intracellular calcium levels were examined in cultured neurons treated with Aβ1-42. The expression of CaV1.2 protein was increased in VD gerbils and in cultured neurons but decreased in APP/PS1 mice; the expression of calmodulin protein was increased in APP/PS1 mice and VD gerbils; levels of p-CaMKII, p-CREB and BDNF proteins were decreased in AD and VD models. The number of neurons in which p-CaMKII and CaV1.2 were co-localized, was decreased in the CA1 and CA3 regions in two models. Intracellular calcium was increased in the cultured neurons treated with Aβ1-42. Collectively, our results suggest that the alterations in CaV1.2, calmodulin, p-CaMKII, p-CREB and BDNF can be reflective of an involvement in the impairment in memory and cognition in AD and VD models.
Yazdanshenas, Hamed; Ashouri, Anousheh; Kaufman, Galen
Introduction Unilateral labyrinthectomy and intra-tympanic gentamycin have been employed in the treatment of Ménière's disease, but the efficacy of these techniques has not been well established. Objective The objective of this study is to measure the time course of recovery from a unilateral labyrinthectomy either after ipsilateral topical treatment with gentamicin to the inner ear or without the previous insult. Methods Twenty-nine adult Mongolian gerbils were randomized into two experimental groups. Group 1 (n = 17) received a right ear gentamicin drug-induced lesion by unilateral labyrinthectomy (UL). Group 2 (n = 12) only received a right unilateral labyrinthectomy lesion. We measured the horizontal vestibulo-ocular responses in gerbils before and after the lesion. The gerbils received an angular acceleration stimulus and their eye movements were recorded. Results The gentamicin lesion resulted in a quicker recovery. Experimental groups underwent a similar time course of recovery. Statistical analysis showed no significant difference between the two groups. Both groups displayed adaptation to the lesion by day 21, but long-term compensation did not completely revert to the original pre-lesion state. Conclusions In a lesion requiring both static and dynamic compensation as in UL, the need for a static compensation may alter pre-existing compensation from a previous dynamic insult and require a new compensation. A previous lesion and adaptation is not preserved for a second lesion and the subject has to re-compensate. Therefore, surgical treatment in Meniere's disease such as UL can be considered without prior gentamicin treatment. Static and dynamic compensations do not appear to be as independent as previous studies have suggested. PMID:27096015
Xu, Lei; Schmid, Boris V.; Liu, Jun; Si, Xiaoyan; Stenseth, Nils Chr.; Zhang, Zhibin
Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change. PMID:25540277
Wilschut, L I; Addink, E A; Heesterbeek, J A P; Dubyanskiy, V M; Davis, S A; Laudisoit, A; M Begon; Burdelov, L A; Atshabar, B B; de Jong, S M
Plague is a zoonotic infectious disease present in great gerbil populations in Kazakhstan. Infectious disease dynamics are influenced by the spatial distribution of the carriers (hosts) of the disease. The great gerbil, the main host in our study area, lives in burrows, which can be recognized on high resolution satellite imagery. In this study, using earth observation data at various spatial scales, we map the spatial distribution of burrows in a semi-desert landscape. The study area consists of various landscape types. To evaluate whether identification of burrows by classification is possible in these landscape types, the study area was subdivided into eight landscape units, on the basis of Landsat 7 ETM+ derived Tasselled Cap Greenness and Brightness, and SRTM derived standard deviation in elevation. In the field, 904 burrows were mapped. Using two segmented 2.5 m resolution SPOT-5 XS satellite scenes, reference object sets were created. Random Forests were built for both SPOT scenes and used to classify the images. Additionally, a stratified classification was carried out, by building separate Random Forests per landscape unit. Burrows were successfully classified in all landscape units. In the 'steppe on floodplain' areas, classification worked best: producer's and user's accuracy in those areas reached 88% and 100%, respectively. In the 'floodplain' areas with a more heterogeneous vegetation cover, classification worked least well; there, accuracies were 86 and 58% respectively. Stratified classification improved the results in all landscape units where comparison was possible (four), increasing kappa coefficients by 13, 10, 9 and 1%, respectively. In this study, an innovative stratification method using high- and medium resolution imagery was applied in order to map host distribution on a large spatial scale. The burrow maps we developed will help to detect changes in the distribution of great gerbil populations and, moreover, serve as a unique empirical
Xu, Lei; Schmid, Boris V; Liu, Jun; Si, Xiaoyan; Stenseth, Nils Chr; Zhang, Zhibin
Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change.
Jie, Hu Jun; Yu, Meng; Fen, Yang Yan; Mei, Guo Yan; Yan, Yang; Esch, G W; QingTuan, Fu
Fecal samples of 945 dogs were examined microscopically in 2 refuge facilities in China from March 2010 to November 2011. In 8 dogs, oocysts, 9-14 μm in size, were found. Their morphology was similar to those of Hammondia heydorni and Neospora caninum. Sporulated Hammondia/Neospora-like oocysts were fed to 2 dogs, 2 gerbils, 2 guinea pigs, and 2 KM mice; tissues from these inoculated animals were then fed to coccidia-free dogs to determine species susceptibility to these oocysts. Oocysts were not excreted in the feces of dogs or rodents inoculated with oocysts. However, the dogs fed the tissues of gerbils or guinea pigs that were inoculated orally with oocysts excreted fresh oocysts. Dogs fed tissues from guinea pigs inoculated with brain and muscular homogenate from guinea pigs that were fed sporulated Hammondia/Neospora-like oocysts did not excrete oocysts. These findings indicated that the oocysts from naturally infected dogs had an obligatory 2-host life cycle, with gerbils and guinea pigs as intermediate hosts. DNA isolated from these oocysts could not be amplified using N. caninum- and Toxoplasma gondii-specific primers. However, positive amplification with the H. heydorni-specific primers confirmed the presence of H. heydorni DNA in the samples. A comparison of the intron 1 sequence of the alpha tubulin gene with those from H. heydorni from dogs and H. triffittae from foxes showed that dog-derived oocysts possessed a different alpha tubulin gene. Both our dog-derived sequence and 2 previous alpha tubulin gene sequences from H. triffittae from foxes contained a 9-bp insertion relative to 3 sequences of H. heydorni from dogs. However, when the 9-bp insertion from H. triffittae sequences were compared, the 9-bp insertion in our dog-derived sequence had a nucleotide substitution. The present study, therefore, provides new evidence of genetic diversity among isolates from dogs. This is the first survey for H. heydorni in dogs from China.
Kim, Mia; Shin, Mal Soon; Lee, Jae Min; Cho, Han Sam; Kim, Chang Ju; Kim, Young Joon; Choi, Hey Ran
Purpose Berberine is a type of isoquinoline alkaloid that has been used to treat various diseases. A neuroprotective effect of berberine against cerebral ischemia has been reported; however, the effects of berberine on apoptosis in relation to reactive astrogliosis and microglia activation under ischemic conditions have not yet been fully evaluated. In the present study, we investigated the effects of berberine on global ischemia-induced apoptosis, and focused on the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway in the hippocampus using gerbils. Methods Gerbils received berberine orally once a day for 14 consecutive days, starting one day after surgery. In this study, a step-down avoidance task was used to assess short-term memory. Furthermore, we employed the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay to evaluate DNA fragmentation, immunohistochemistry to investigate glial fibriallary acidic protein, CD11b, and caspase-3, and western blot to assess PI3K, Akt, Bax, Bcl-2, and cytochrome c. Results Our results revealed that berberine treatment alleviated ischemia-induced short-term memory impairment. Treatment with berbeine also attenuated ischemia-induced apoptosis and inhibited reactive astrogliosis and microglia activation. Furthermore, berberine enhanced phospho-PI3K and phospho-Akt expression in the hippocampus of ischemic gerbils. Conclusions Berberine exerted a neuroprotective effect against ischemic insult by inhibiting neuronal apoptosis via activation of the PI3K/Akt signaling pathway. The antiapoptotic effect of berberine was achieved through inhibition of reactive astrogliosis and microglia activation. Berberine may therefore serve as a therapeutic agent for stroke-induced neurourological problems. PMID:25279238
Wang, Ge; Romero-Gallo, Judith; Benoit, Stéphane L.; Piazuelo, M. Blanca; Dominguez, Ricardo L.; Morgan, Douglas R.; Peek, Richard M.
ABSTRACT A known virulence factor of Helicobacter pylori that augments gastric cancer risk is the CagA cytotoxin. A carcinogenic derivative strain, 7.13, that has a greater ability to translocate CagA exhibits much higher hydrogenase activity than its parent noncarcinogenic strain, B128. A Δhyd mutant strain with deletion of hydrogenase genes was ineffective in CagA translocation into human gastric epithelial AGS cells, while no significant attenuation of cell adhesion was observed. The quinone reductase inhibitor 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO) was used to specifically inhibit the H2-utilizing respiratory chain of outer membrane-permeabilized bacterial cells; that level of inhibitor also greatly attenuated CagA translocation into AGS cells, indicating the H2-generated transmembrane potential is a contributor to toxin translocation. The Δhyd strain showed a decreased frequency of DNA transformation, suggesting that H. pylori hydrogenase is also involved in energizing the DNA uptake apparatus. In a gerbil model of infection, the ability of the Δhyd strain to induce inflammation was significantly attenuated (at 12 weeks postinoculation), while all of the gerbils infected with the parent strain (7.13) exhibited a high level of inflammation. Gastric cancer developed in 50% of gerbils infected with the wild-type strain 7.13 but in none of the animals infected with the Δhyd strain. By examining the hydrogenase activities from well-defined clinical H. pylori isolates, we observed that strains isolated from cancer patients (n = 6) have a significantly higher hydrogenase (H2/O2) activity than the strains isolated from gastritis patients (n = 6), further supporting an association between H. pylori hydrogenase activity and gastric carcinogenesis in humans. PMID:27531909
Primary alveolar echinococcosis: course of larval development and antibody responses in intermediate host rodents with different genetic backgrounds after oral infection with eggs of Echinococcus multilocularis.
Matsumoto, Jun; Kouguchi, Hirokazu; Oku, Yuzaburo; Yagi, Kinpei
We investigated parasite establishment, subsequent larval development and antibody responses in gerbils, cotton rats and 4 inbred mouse strains until 16 weeks post inoculation (p.i.) with 200 eggs of Echinococcus multilocularis. The rate of parasite establishment in the liver determined at 4 weeks p.i. was highest in DBA/2, followed by AKR/N, C57BL/10 and C57BL/6 mice, whereas gerbils harboured few parasite foci. The accurate number of liver lesions in cotton rats could not be determined due to rapid growth and advanced multivesiculation of the parasite observed at 2 weeks p.i. The course of larval development was most advanced in DBA/2 mice with mature protoscolex formation at 16 weeks p.i., followed by AKR/N harbouring metacestodes with sparsely distributed immature protoscoleces. On the other hand, C57BL/6 and C57BL/10 mice had infertile metacestodes without any protoscolex formation. The parasite growth in mice was totally slower than those in gerbils and cotton rats. Specific IgG and IgM responses against 3 types of native crude antigens of larval E. multilocularis were evaluated using somatic extracts of and vesicle fluid of metacestode, and somatic extracts from purified protoscoleces. The 4 mouse strains demonstrated basically similar kinetics with apparent IgG and IgM increases at 9 weeks p.i. and thereafter, except C57BL/10, exhibited higher levels of IgM against crude antigens at some time point of infection. On the other hand, a follow-up determination of specific IgG and IgM levels against recombinant antigens from larval E. multilocularis revealed that each mouse strain showed different antibody-level kinetics. The findings in the present study demonstrate that the course of host-parasite interactions in primary alveolar echinococcosis, caused by larval E. multilocularis, clearly varies among intermediate host rodents with different genetic backgrounds.
Veysi, Arshad; Vatandoost, Hassan; Arandian, Mohammad Hossein; Jafari, Reza; Yaghoobi-Ershadi, Mohammad Reza; Rassi, Yavar; Akhavan, Amir Ahmad
Background Zoonotic cutaneous leishmaniasis is a growing health problem in many rural areas of Iran. Rhombomys opimus, the great gerbil, is the main animal reservoir of ZCL in the northeast and central part of Iran. The aim of the current study was to evaluate the rodenticidal effect of Coumavec® (a mixture of Coumatetralyl 0.5% and Etofenprox 0.5%) on R. opimus under laboratory condition. Methods: Great gerbils were collected from Sejzi rural district, Esfahan Province, Iran. Four groups of 19 great gerbils were treated with the poisoned baits of different concentrations and one group was considered as control. The bating procedure was conducted in three stages: first, second (a week after first) and third (a month after first stage), in each stage baits were offered in 1 day, based on national protocol for rodent control operation in purpose of ZCL control. Results: The mortality rate for 0.03, 0.0625, 0.125 and 0.25% concentrations in the first stage of baiting were obtained 36.8%, 31.5%, 52.6% and 36.8%, in the second stage 47.3%, 52.6%, 68.4% and 52.6%, and in the third stage 52.6%, 63.1%, 68.4% and 57.8% respectively. The maximum and minimum mortality has occurred in 5–6 days and 31–40 days intervals consequently. Conclusion: The results of this study showed that, Coumavec® has some rodenticidal effects on R. opimus in laboratory condition. For the appropriate rodenticide-insecticide contamination of the rodent body and also considering to the economic issues, we suggest the use of 0.125% concentration for rodent control operation in the field condition. PMID:24409445
of gonads and/or neurons. This study evaluated the existence of age-related changes in transcriptional expression of HSC70, HSP72 , and c-fos mRNA...young animals compared with that in adult animals showed: (1) more rapid and /or prolonged expression of HSC70, HSP72 , and c-fos mRNAs; (2) a marked...induction of HSP72 protein; and (3) enhanced pyramidal cell survival. The observed endogenous ’tolerance’ of CA1 neurons in young gerbils to ischemia/reperfusion injury may be related to the expression of HSC70, HSP72 and c-fos.
Reliable estimates are lacking of key epizootiologic parameters for plague caused by Yersinia pestis infection in its natural reservoirs. We report results of a 3-year longitudinal study of plague dynamics in populations of a maintenance host, the great gerbil (Rhombomys opimus), in 2 populations in Kazakhstan. Serologic results suggest a mid-summer peak in the abundance of infectious hosts and possible transmission from the reservoir to humans. Decrease in antibody titer to an undetectable level showed no seasonal pattern. Our findings did not support the use of the nitroblue-tetrazolium test characterization of plague-infected hosts. Y. pestis infection reduced survival of otherwise asymptomatic hosts.
Background Plague (Yersinia pestis infection) is a vector-borne disease which caused millions of human deaths in the Middle Ages. The hosts of plague are mostly rodents, and the disease is spread by the fleas that feed on them. Currently, the disease still circulates amongst sylvatic rodent populations all over the world, including great gerbil (Rhombomys opimus) populations in Central Asia. Great gerbils are social desert rodents that live in family groups in burrows, which are visible on satellite images. In great gerbil populations an abundance threshold exists, above which plague can spread causing epizootics. The spatial distribution of the host species is thought to influence the plague dynamics, such as the direction of plague spread, however no detailed analysis exists on the possible functional or structural corridors and barriers that are present in this population and landscape. This study aims to fill that gap. Methods Three 20 by 20 km areas with known great gerbil burrow distributions were used to analyse the spatial distribution of the burrows. Object-based image analysis was used to map the landscape at several scales, and was linked to the burrow maps. A novel object-based method was developed – the mean neighbour absolute burrow density difference (MNABDD) – to identify the optimal scale and evaluate the efficacy of using landscape objects as opposed to square cells. Multiple regression using raster maps was used to identify the landscape-ecological variables that explain burrow density best. Functional corridors and barriers were mapped using burrow density thresholds. Cumulative resistance of the burrow distribution to potential disease spread was evaluated using cost distance analysis. A 46-year plague surveillance dataset was used to evaluate whether plague spread was radially symmetric. Results The burrow distribution was found to be non-random and negatively correlated with Greenness, especially in the floodplain areas. Corridors and
Klassovskiy, Nikolay; Ageyev, Vladimir; Suleimenov, Bakhtiar; Atshabar, Bakhyt; Bennett, Malcolm
Reliable estimates are lacking of key epizootiologic parameters for plague caused by Yersinia pestis infection in its natural reservoirs. We report results of a 3-year longitudinal study of plague dynamics in populations of a maintenance host, the great gerbil (Rhombomys opimus), in 2 populations in Kazakhstan. Serologic results suggest a mid-summer peak in the abundance of infectious hosts and possible transmission from the reservoir to humans. Decrease in antibody titer to an undetectable level showed no seasonal pattern. Our findings did not support the use of the nitroblue-tetrazolium test characterization of plague-infected hosts. Y. pestis infection reduced survival of otherwise asymptomatic hosts. PMID:16494753
Evans, Erika E; Souza, Marcy J
African pygmy and European hedgehogs, sugar gliders, and rodents such as rats, mice, gerbils, hamsters, guinea pigs, and chinchillas are becoming increasingly popular as pets in the United States, and more practitioners are being asked to examine, diagnose, and treat these animals for a bevy of disorders and diseases. Many procedures and techniques used in traditional small and large animal medicine are used for these species, with minor adaptations or considerations. This article examines available diagnostic tools and treatment methodologies for use in hedgehogs, sugar gliders, and selected rodents.
Hughes, S E; Sloan, H E; Jones, L B; Oakley, B
A Silastic cuff containing either colchicine (1% w/v) or no colchicine was placed around the lingual disorder tympani nerve of the Mongolian gerbil. After 3 days of exposure to colchicine, the mean period of the myelin sheaths was 23% less than the period observed in nerves treated with cuffs lacking colchicine, while the average number of lamellae was unaltered. At the same time colchicine reduced the volume of axoplasm by an average of 19%, an effect which was independent of fiber diameter.
Pritchett-Corning, Kathleen R; Peery, Harry E; Crossland, Janet P; Wyatt, Heather M; Stuart, Marilyne; Mothersill, Carmel E
Helicobacter species can be found in a wide variety of animals and remain common contaminants of laboratory rodents. Fostering of neonatal pups has been used to eliminate Helicobacter spp. from various laboratory rodents, including laboratory mice and gerbils. Deer mice (Peromyscus maniculatus) from a captive colony enzootic for at least one Helicobacter species were mated, and the pups produced were fostered on laboratory mice 24 h after birth. After 2 rounds of fostering, both foster dams and pups were free of Helicobacter spp. as determined by fecal PCR analysis. Removal of Helicobacter infection through neonatal fostering has not been described previously for Peromyscus maniculatus. PMID:26224445
Nikaido, M; Kawai, K; Cao, Y; Harada, M; Tomita, S; Okada, N; Hasegawa, M
The complete mitochondrial genomes of two microbats, the horseshoe bat Rhinolophus pumilus, and the Japanese pipistrelle Pipistrellus abramus, and that of an insectivore, the long-clawed shrew Sorex unguiculatus, were sequenced and analyzed phylogenetically by a maximum likelihood method in an effort to enhance our understanding of mammalian evolution. Our analysis suggested that (1) a sister relationship exists between moles and shrews, which form an eulipotyphlan clade; (2) chiropterans have a sister-relationship with eulipotyphlans; and (3) the Eulipotyphla/Chiroptera clade is closely related to fereuungulates (Cetartiodactyla, Perissodactyla and Carnivora). Divergence times on the mammalian tree were estimated from consideration of a relaxed molecular clock, the amino acid sequences of 12 concatenated mitochondrial proteins and multiple reference criteria. Moles and shrews were estimated to have diverged approximately 48 MyrBP, and bats and eulipotyphlans to have diverged 68 MyrBP. Recent phylogenetic controversy over the polyphyly of microbats, the monophyly of rodents, and the position of hedgehogs is also examined.
The related new genera Austrocyphon and Tasmanocyphon are erected for 42 small Australian marsh beetles resembling members of the genus Cyphon Paykull in habitus. They are distinguished from Cyphon. Only males are known of most species but for two of them larvae and pupae are also available. Austrocyphon species occur in all Australian Federal States, and one species is Australasian and shared with Papua New Guinea. The following species are included: Austrocyphon acaciae sp. n., A. aculeatus sp. n., A. acustropicus sp. n., A. adelaidae (Blackburn), A. asper sp. n., A. bidens sp. n., A. bifidus sp. n., A. charon sp. n., A. crinitus (Klausnitzer), A. curvispina, sp. n., A. deserticola sp. n., A. doctus (Lea), A. enigmaticus sp. n., A. excisus sp. n., A. fenestratus (Blackburn), A. flagellifer sp. n., A. furcatus sp. n., A. hamatus sp. n., A. harpago sp. n., A. leptophallus sp. n., A. linguatus sp. n., A. lobatus sp. n., A. neptunus sp. n., A. noctua sp. n., A. ovensensis (Blackburn), A. papilio sp. n., A. perdoctus sp. n., A. pictus (Blackburn), A. quadridens sp. n., A. quinquespinosus sp. n., A. robustus sp. n., A. setifer sp. n., A. spiculifer sp. n., A. stylatus sp. n., A. stylifer sp. n., A. submersus sp. n., A. tinea sp. n., A. tomweiri sp. n., A. tribulator sp. n., A. tropicus sp. n., A. unguiculatus sp. n., A. wattsi sp. n.Tasmanocyphon is endemic to Tasmania, and only the adult male is known. The genus is monotypic, including only T. heideae, sp. n.
Sato, Itaru; Nakaki, Shinichi; Murata, Koichi; Takeshita, Hiroshi; Mukai, Toshiji
As part of an investigation of a case of pet animal abuse, we attempted to identify small mammalian species by morphological analysis and single-nucleotide polymorphism (SNP) typing of the cytochrome b gene using guard hairs as an analytical material. Guard hair samples from several species were measured for length, width, medulla formation, and cuticle scale pattern under a light microscope or scanning electron microscope. These samples were also analyzed for SNPs in the cytochrome b gene using a multiplex single-base primer extension reaction. Morphological analysis of cuticle scale pattern and medulla formation was able to discriminate ferret hairs from other hair samples that included rabbit, gerbil, degu, and Djungarian hamster. However, this also revealed a similarity of the guard hairs of the ferret (Mustela putorius furo) and Japanese weasel (Mustela itatsi). Although at three sites, the nucleotide color signals of SNPs in the cytochrome b gene could be used to discriminate completely among human, dog, and gerbil, the signals for cat, ferret, and Japanese weasel occurred at the same nucleotide sites. Unfortunately, no signals were obtained from degu, Djungarian hamster, and rabbit hairs. Although the discriminated hair samples were 100% identical to those of the ferret, there was only a 5% difference from Japanese weasel in the partial sequence of the cytochrome b gene. Construction of a database of mammalian hairs would be useful not only in forensic science, but also for investigating smuggling of endangered species in contravention of the Washington Convention.
Kanski, J; Lauderback, C; Butterfield, D A
The antioxidant properties of 5-aminosalicylic acid in vitro were evaluated in a synaptosomal membrane system prepared from gerbil cortical synaptosomes using EPR spin labeling and spectroscopic techniques. MAL-6 (2,2,6,6-tetramethyl-4-maleimidopiperidin-1-oxyl) and 5-NS (5-nitroxide stearate) spin labels were used to assess changes in protein oxidation and membrane lipid fluidity, respectively. Synaptosomal membranes were subjected to oxidative stress by incubation with 1 mM azo-bis(isobutyronitrile) (AIBN) or 1 mM 2,2'-azobis(amidino propane) dihydrochloride (AAPH) at 37 degrees C for 30 minutes. The EPR analyses of the samples showed significant oxidation of synaptosomal proteins and a decrease in membrane fluidity. 5-Aminosalicylic acid also was evaluated by means of FRAP (the ferric reducing ability of plasma) test as a potential antioxidant. 5-Aminosalicylic acid also showed protection against the oxidation in gerbil cortical synaptosomes system caused by AIBN and AAPH. These results are consistent with the notion of antioxidant protection against free radical induced oxidative stress in synaptosomal membrane system by this agent.
Chirgwin, Sharon R; Coleman, Sharon U; Porthouse, Kristina H; Klei, Thomas R
Infection with mosquito-born filarial nematodes occurs when hosts are bitten by a vector carrying the infective third stage larvae (L3) of the parasites. These larvae, deposited on the skin by the feeding mosquito, are presumed to enter the skin via the vector-induced puncture wound. Larvae of Brugia spp. must then migrate from the entry site, penetrate various skin layers, and locate a lymphatic vessel that leads to their lymphatic predilection site. We have recently established an intradermal (ID) infection model using B. pahangi and the Mongolian gerbil, allowing us to investigate the migratory capability ofB. pahangi. Larval and adult parasites recovered from the peritoneal cavities of gerbils were capable of establishing an infection following ID (larvae) or subcutaneous (adult) injection. Third and fourth stage larvae both migrated away from the injection site within hours, although data suggest they localize to different lymphatic tissues at 3 days postinfection (DPI). Immature adult (28 day) B. pahangi also migrated away from their SC inoculation site within 7 DPI. Mature (45 day) adult B. pahangi displayed little migration away from the SC infection site, suggesting tissue migration may be limited to developing stages of the parasite.
Plavsic, Militsa Justine
Disturbance is now recognized as a key ecosystem process but few studies have examined its indirect effects on individuals in a population or its relationship to ecological dominance in a community. Using an ecologically dominant small mammal population in experimentally burned habitat as a model, I empirically tested the effect of disturbance on survival, abundance and fecundity and investigated whether recently burned habitat is a population sink. I also examined the effect of fire on community diversity, particularly how fire influenced dominance by bushveld gerbils Tatera leucogaster (Peters 1852). Live trapping in the first year post-fire yielded a total of 4,774 captures of 1,076 individual bushveld gerbils in a tropical savanna in southern Africa. The robust design allowed for an investigation of the effects of fire, sex and temporal variation on survival while controlling for potential differences in detection and temporary emigration. Although there were fewer individuals in burned savanna during the first 6 months post-fire, their apparent monthly survival was not significantly lowered compared with the control, with males and females surviving equally well. Fecundity, represented by proportion of females lactating, was unaffected by fire and, overall, recently burned habitat does not appear to be sink habitat. The disturbance resistance exhibited by this species is likely a contributing factor to its ecological dominance in the area, which is subject to relatively frequent fires. Results of this study highlight the need to consider disturbance regimes when evaluating patterns of species richness and evenness in an ecosystem.
Embar, Keren; Raveh, Ashael; Burns, Darren; Kotler, Burt P
In a foraging game, predators must catch elusive prey while avoiding injury. Predators manage their hunting success with behavioral tools such as habitat selection, time allocation, and perhaps daring-the willingness to risk injury to increase hunting success. A predator's level of daring should be state dependent: the hungrier it is, the more it should be willing to risk injury to better capture prey. We ask, in a foraging game, will a hungry predator be more willing to risk injury while hunting? We performed an experiment in an outdoor vivarium in which barn owls (Tyto alba) were allowed to hunt Allenby's gerbils (Gerbillus andersoni allenbyi) from a choice of safe and risky patches. Owls were either well fed or hungry, representing the high and low state, respectively. We quantified the owls' patch use behavior. We predicted that hungry owls would be more daring and allocate more time to the risky patches. Owls preferred to hunt in the safe patches. This indicates that owls manage risk of injury by avoiding the risky patches. Hungry owls doubled their attacks on gerbils, but directed the added effort mostly toward the safe patch and the safer, open areas in the risky patch. Thus, owls dared by performing a risky action-the attack maneuver-more times, but only in the safest places-the open areas. We conclude that daring can be used to manage risk of injury and owls implement it strategically, in ways we did not foresee, to minimize risk of injury while maximizing hunting success.
Horemans, Tessa; Boulet, Gaëlle; van Kerckhoven, Marian; Bogers, Johannes; Thys, Sofie; Vervaet, Chris; Vervaeck, Anouck; Delputte, Peter; Maes, Louis; Cos, Paul
The emergence of antibiotic-resistant Helicobacter pylori strains impacts the efficacy of eradication therapy and promotes the development of alternative treatment strategies. Apocynin inhibits neutrophil NADPH oxidase and hence may decrease reactive oxygen species-mediated tissue damage in H. pylori-infected stomach tissue. Apocynin was tested in vitro for its cytotoxic and direct antibacterial effects. The therapeutic efficacy of orally administered apocynin (100 mg/kg/day through drinking water or 200 mg/kg/day through combined administration of drinking water and slow-release formulation) was assessed at 9 weeks after infection in the Mongolian gerbil model. Bacterial burdens were quantified by viable plate count and quantitative PCR. Histopathological evaluation of antrum and pylorus provided insight into mucosal inflammation and injury. Apocynin showed no cytotoxic or direct antibacterial effects in vitro or in vivo. Nine weeks of apocynin treatment at 200 mg/kg/day reduced active H. pylori gastritis as neutrophil infiltration in the mucous neck region and pit abscess formation decreased significantly. In our gerbil model, prolonged high-dose apocynin treatment significantly improved H. pylori-induced pit abscess formation without indications of drug toxicity and thus further investigation of the dosage regimen and formulation and the long-term impact on neoplastic development should be carried out.
YOON, YONGJIN; PURIA, SUNIL; STEELE, CHARLES R.
In our previous work, the basilar membrane velocity VBM for a gerbil cochlea was calculated and compared with physiological measurements. The calculated VBM showed excessive phase excursion and, in the active case, a best-frequency place shift of approximately two fifths of an octave higher. Here we introduce a refined model that uses the time-averaged Lagrangian for the conservative system to resolve the phase excursion issues. To improve the overestimated best-frequency place found in the previous feed-forward active model, we implement in the new model a push-pull mechanism from the outer hair cells and phalangeal process. Using this new model, the VBM for the gerbil cochlea was calculated and compared with animal measurements, The results show excellent agreement for mapping the location of the maximum response to frequency, while the agreement for the response at a fixed point as a function of frequency is excellent for the amplitude and good for the phase. PMID:20485540
Songsri, Jiraporn; Aukkanimart, Ratchadawan; Boonmars, Thidarut; Ratanasuwan, Panaratana; Laummaunwai, Porntip; Sriraj, Pranee; Sripan, Panupan
Echinostomes are intestinal trematodes that infect a wide range of vertebrate hosts, including humans, in their adult stage and also parasitize numerous invertebrate and cold-blooded vertebrate hosts in their larval stages. The purpose of this study was to compare Echinostoma malayanum parasite growth, including worm recovery, body size of adult worms, eggs per worm, eggs per gram of feces, and pathological changes in the small intestine of experimental animals. In this study, 6-8-week-old male hamsters, rats, mice, and gerbils were infected with echinostome metacercariae and then sacrificed at day 60 post-infection. The small intestine and feces of each infected animal were collected and then processed for analysis. The results showed that worm recovery, eggs per worm, and eggs per gram of feces from all infected hamsters were higher compared with infected rats and mice. However, in infected gerbils, no parasites were observed in the small intestine, and there were no parasite eggs in the feces. The volume of eggs per gram of feces and eggs per worm were related to parasite size. The results of histopathological changes in the small intestine of infected groups showed abnormal villi and goblet cells, as evidenced by short villi and an increase in the number and size of goblet cells compared with the normal control group. PMID:26951978
Rajinikanth, Paruvathanahalli Siddalingam; Karunagaran, Lakshmi Narayanan; Balasubramaniam, Jagdish; Mishra, Brahmeshwar
The objective of the study was to develop a stomach-specific drug delivery system for controlled release of clarithromycin for eradication of Helicobacter pylori (H. pylori). Floating-bioadhesive microspheres of clarithromycin (FBMC) were prepared by emulsification-solvent evaporation method using ethylcellulose as matrix polymer and Carbopol 934P as mucoadhesive polymer. The prepared microspheres were subjected to evaluation for particle size, incorporation efficiency, in vitro buoyancy, in vitro mucoadhesion and in vitro drug release characteristics. The prepared microspheres showed a strong mucoadhesive property with good buoyancy. The formulation variables like polymer concentration and drug concentration influenced the in vitro drug release significantly in simulated gastric fluid (pH. 2.0). The in vivo H. pylori clearance efficiency of prepared FBMC in reference to clarithromycin suspension following repeated oral administration to H. pylori infected Mongolian gerbils was examined by polymerase chain reaction (PCR) technique and by a microbial culture method. The FBMC showed a significant anti-H. pylori effect in the in vivo gerbil model. It was also noted that the required amount of clarithromycin for eradication of H. pylori was significantly less in FBMC than from corresponding clarithromycin suspension. The results further substantiated that FBMC improved the gastric stability of clarithromycin (due to entrapment within the microsphere) and eradicated H. pylori from the gastrointestinal tract more effectively than clarithromycin suspension because of the prolonged gastrointestinal residence time of the formulation.
Yoon, Yong-Jin; Steele, Charles R.; Puria, Sunil
The high sensitivity and wide bandwidth of mammalian hearing are thought to derive from an active process involving the somatic and hair-bundle motility of the thousands of outer hair cells uniquely found in mammalian cochleae. To better understand this, a biophysical three-dimensional cochlear fluid model was developed for gerbil, chinchilla, cat, and human, featuring an active “push-pull” cochlear amplifier mechanism based on the cytoarchitecture of the organ of Corti and using the time-averaged Lagrangian method. Cochlear responses are simulated and compared with in vivo physiological measurements for the basilar membrane (BM) velocity, VBM, frequency tuning of the BM vibration, and Q10 values representing the sharpness of the cochlear tuning curves. The VBM simulation results for gerbil and chinchilla are consistent with in vivo cochlea measurements. Simulated mechanical tuning curves based on maintaining a constant VBM value agree with neural-tuning threshold measurements better than those based on a constant displacement value, which implies that the inner hair cells are more sensitive to VBM than to BM displacement. The Q10 values of the VBM tuning curve agree well with those of cochlear neurons across species, and appear to be related in part to the width of the basilar membrane. PMID:21190651
Holman, B.L.; Jolesz, F.A.; Polak, J.F.; Kronauge, J.F.; Adams, D.F.
Both I-123 IMP scintigraphy and MRI have been suggested as sensitive detectors of changes shortly after acute cerebral infarction. We compared the uptake of N-isopropyl I-123 p-iodoamphetamine (IMP) and MR spectroscopy of the brain after internal carotid artery ligation. Thirteen gerbils were lightly anesthetized with ether. After neck dissection, an internal carotid artery was occluded. After 2.8 hours, 100 muCi I-123 IMP was injected intravenously into the 13 experimental animals plus three controls. Seven gerbils remained asymptomatic while six developed hemiparesis. At 3 hours after ligation, the animals were killed. The brains were bisected and T1 and T2 relaxation times were determined for the right and left hemispheres by MR spectroscopy immediately after dissection. I-123 IMP uptake was then determined in the samples. Interhemispheric differences in uptake for I-123 IMP were 0.1 +/- 1.7% (SEM) in the control, 33.5 +/- 10% in the asymptomatic and 54.6 +/- 9.7% in the symptomatic animals. Significant differences were seen with I-123 IMP in 6/7 asymptomatic and 6/6 symptomatic animals. In conclusion, I-123 is more sensitive than T1 or T2 relaxation times for the detection of cerebral perfusion abnormalities. Prolongation in T1 and T2 relaxation times correlates closely with increased brain tissue water content and the development of symptoms, indicators of structural brain damage and probable infarction.
Matic, Agnella Izzo; Walsh, Joseph T.; Richter, Claus-Peter
Artificial neural stimulation is widely used in clinic, rehabilitation, and research. One of the limitations of electrical stimulation is the current spread in tissue. Recently, pulsed mid-infrared laser stimulation of nerves has been investigated as an alternative stimulation method. The likely benefits of infrared neural stimulation (INS) include spatial selectivity of stimulation, noncontact mode of operation, and the lack of stimulation artifact in simultaneous electrical recordings. The hypothesis for this study is that INS of the cochlear spiral ganglion at low pulse energy is as spatially selective as low-level tonal stimulation of the cochlea. Spatial selectivity was measured using a masking method. An optical pulse with fixed optical parameters was delivered through a 200-μm diameter optical fiber. An acoustic tone, variable in frequency and level, was presented simultaneously with the optical pulse. Tone-on-light masking in gerbils revealed tuning curves with best frequencies between 5.3 and 11.4 kHz. The width of the tone-on-light tuning curves was similar to the width of tone-on-tone tuning curves. The results indicate that the spatial area of INS in the gerbil cochlea is similar to the cochlear area excited by a low level acoustic tone, showing promising results for future use of INS in implantable cochlear prostheses.
Reynoso-Robles, R.; Ponce-Macotela, M.; Rosas-López, L. E.; Ramos-Morales, A.; Martínez–Gordillo, M. N.; González-Maciel, A.
Giardiasis is a neglected parasitic disease that affects primarily children, in whom it delays physical and mental development. The pathophysiology of giardiasis in not well understood, and most reports have identified Giardia intestinalis trophozoites only in the lumen and on the brush border of the small intestine. We identified Giardia trophozoites within the epithelium of the small intestine of a lactose intolerance patient. The Giardia trophozoites were obtained and cultured in vitro. In addition, we demonstrated Giardia trophozoite invasion in an animal model. Giardia trophozoites invaded the intestinal mucosa and submucosa of infected gerbils. The invasive trophozoites were observed at 21, 30 and 60 days age, and the average numbers of invaded sites were 17 ± 5, 15 ± 4, and 9 ± 3, respectively. We found trophozoites between epithelial cells, at the base of empty goblet cells, in lacteal vessels and within the submucosa. The morphological integrity of the invasive trophozoites was demonstrated via electron microscopy. The analysis of the gerbils infected with the trophozoites of the WB reference strain did not show intraepithelial trophozoites. These results demonstrate another Giardia pathogenic mechanism, opening the door to numerous future studies. PMID:26470844
Schulte, Bradley A.; Goddard, John C.; Hedrick, Michelle; Schulte, Jason B.; Wei, Ling; Schmiedt, Richard A.
Application of ouabain to the round window membrane of the gerbil selectively induces the death of most spiral ganglion neurons and thus provides an excellent model for investigating the survival and differentiation of embryonic stem cells (ESCs) introduced into the inner ear. In this study, mouse ESCs were pretreated with a neural-induction protocol and transplanted into Rosenthal’s canal (RC), perilymph, or endolymph of Mongolian gerbils either 1–3 days (early post-injury transplant group) or 7 days or longer (late post-injury transplant group) after ouabain injury. Overall, ESC survival in RC and perilymphatic spaces was significantly greater in the early post-injury microenvironment as compared to the later post-injury condition. Viable clusters of ESCs within RC and perilymphatic spaces appeared to be associated with neovascularization in the early post-injury group. A small number of ESCs transplanted within RC stained for mature neuronal or glial cell markers. ESCs introduced into perilymph survived in several locations, but most differentiated into glia-like cells. ESCs transplanted into endolymph survived poorly if at all. These experiments demonstrate that there is an optimal time window for engraftment and survival of ESCs that occurs in the early post-injury period. PMID:18449604
Narui, Yuya; Minekawa, Akira; Iizuka, Takashi; Furukawa, Masayuki; Kusunoki, Takeshi; Koike, Takuji; Ikeda, Katsuhisa
Distortion product otoacoustic emissions (DPOAEs) have been used to examine the development of hearing in the rat and gerbil. However, no reports of DPOAE measurement from the onset of hearing in mice are available. Commercially-available components were assembled and adapted to provide a suitable probe microphone and sound delivery system for measuring DPOAE in developing C57BL/6J mice. Furthermore, DPOAE data were compared with the findings of the auditory brainstem response (ABR). DPOAEs were obtained at 8 kHz from 11 days after birth, 20 kHz from 12 days, and 30 kHz from 13 days. Adult-like patterns of DPOAE were obtained 21 days at 8 and 20 kHz, and 28 days at 30 kHz. On the other hand, the ABR thresholds at 12 to 36 kHz appeared between 11 and 12 days and were saturated at 14 days. Based on these data, the onset of measureable DPOAEs in the mouse were earlier than in the rat and gerbil. The maturation of DPOAE in the mouse begins at a lower frequency in the high frequency range. In addition, the ABR threshold reached maturation earlier than DPOAE.
Stange, Annette; Myoga, Michael H; Lingner, Andrea; Ford, Marc C; Alexandrova, Olga; Felmy, Felix; Pecka, Michael; Siveke, Ida; Grothe, Benedikt
Across all sensory modalities, the effect of context-dependent neural adaptation can be observed at every level, from receptors to perception. Nonetheless, it has long been assumed that the processing of interaural time differences, which is the primary cue for sound localization, is nonadaptive, as its outputs are mapped directly onto a hard-wired representation of space. Here we present evidence derived from in vitro and in vivo experiments in gerbils indicating that the coincidence-detector neurons in the medial superior olive modulate their sensitivity to interaural time differences through a rapid, GABA(B) receptor-mediated feedback mechanism. We show that this mechanism provides a gain control in the form of output normalization, which influences the neuronal population code of auditory space. Furthermore, psychophysical tests showed that the paradigm used to evoke neuronal GABA(B) receptor-mediated adaptation causes the perceptual shift in sound localization in humans that was expected on the basis of our physiological results in gerbils.
Li, Liwen; Tang, Qinghuang; Nakamura, Takashi; Suh, Jun-Gyo; Ohshima, Hayato; Jung, Han-Sung
The anatomic and functional combinations of cusps and lophs (ridges) define the tooth shape of rodent molars, which distinguishes species. The species-specific cusp patterns result from the spatiotemporal induction of enamel knots (EKs), which require precisely controlled cellular behavior to control the epithelial invagination. Despite the well-defined roles of EK in cusp patterning, the determinants of the ultimate cuspal shapes and involvement of epithelial cellular geometry are unknown. Using two typical tooth patterns, the lophodont in gerbils and the bunodont in mice, we showed that the cuspal shape is determined by the dental epithelium at the cap stage, whereas the cellular geometry in the inner dental epithelium (IDE) is correlated with the cuspal shape. Intriguingly, fine tuning Rac1 and RhoA interconvert cuspal shapes between two species by remolding the cellular geometry. Either inhibition of Rac1 or ectopic expression of RhoA could region-distinctively change the columnar shape of IDE cells in gerbils to drive invagination to produce cusps. Conversely, RhoA reduction in mice inhibited invagination and developed lophs. Furthermore, we found that Rac1 and RhoA modulate the choices of cuspal shape by coordinating adhesion junctions, actin distribution, and fibronectin localization to drive IDE invagination. PMID:27892530
Wilschut, L.I.; Addink, E.A.; Heesterbeek, J.A.P.; Dubyanskiy, V.M.; Davis, S.A.; Laudisoit, A.; M.Begon; Burdelov, L.A.; Atshabar, B.B.; de Jong, S.M.
Plague is a zoonotic infectious disease present in great gerbil populations in Kazakhstan. Infectious disease dynamics are influenced by the spatial distribution of the carriers (hosts) of the disease. The great gerbil, the main host in our study area, lives in burrows, which can be recognized on high resolution satellite imagery. In this study, using earth observation data at various spatial scales, we map the spatial distribution of burrows in a semi-desert landscape. The study area consists of various landscape types. To evaluate whether identification of burrows by classification is possible in these landscape types, the study area was subdivided into eight landscape units, on the basis of Landsat 7 ETM+ derived Tasselled Cap Greenness and Brightness, and SRTM derived standard deviation in elevation. In the field, 904 burrows were mapped. Using two segmented 2.5 m resolution SPOT-5 XS satellite scenes, reference object sets were created. Random Forests were built for both SPOT scenes and used to classify the images. Additionally, a stratified classification was carried out, by building separate Random Forests per landscape unit. Burrows were successfully classified in all landscape units. In the ‘steppe on floodplain’ areas, classification worked best: producer's and user's accuracy in those areas reached 88% and 100%, respectively. In the ‘floodplain’ areas with a more heterogeneous vegetation cover, classification worked least well; there, accuracies were 86 and 58% respectively. Stratified classification improved the results in all landscape units where comparison was possible (four), increasing kappa coefficients by 13, 10, 9 and 1%, respectively. In this study, an innovative stratification method using high- and medium resolution imagery was applied in order to map host distribution on a large spatial scale. The burrow maps we developed will help to detect changes in the distribution of great gerbil populations and, moreover, serve as a unique
Turner, J Scott; Pinshow, Berry
Burrows are common animal habitations, yet living in a burrow presents physiological challenges for its inhabitants because the burrow isolates them from sources and sinks for oxygen, carbon dioxide, water vapor and ammonia. Conventionally, the isolation is thought to be overcome by either diffusion gas exchange within the burrow or some means of capturing wind energy to power steady or quasi-steady bulk flows of air through it. Both are examples of what may be called 'DC' models, namely steady to quasi-steady flows powered by steady to quasi-steady winds. Natural winds, however, are neither steady nor quasi-steady, but are turbulent, with a considerable portion of the energy contained in so-called 'AC' (i.e. unsteady) components, where wind velocity varies chaotically and energy to power gas exchange is stored in some form. Existing DC models of burrow gas exchange do not account for this potentially significant source of energy for ventilation. We present evidence that at least two AC mechanisms operate to ventilate both single-opening burrows (of the Cape skink, Trachylepis capensis) and double-opening model burrows (of Sundevall's jird, Meriones crassus). We propose that consideration of the physiological ecology and evolution of the burrowing habit has been blinkered by the long neglect of AC ventilation.
Marciano, Odelya; Gutiérrez, Ricardo; Morick, Danny; King, Roni; Nachum-Biala, Yaarit; Baneth, Gad; Harrus, Shimon
Bartonella infection was explored in wild animals from Israel. Golden jackals (Canis aureus), red foxes (Vulpes vulpes), rock hyraxes (Procavia capensis), southern white-breasted hedgehogs (Erinaceus concolor), social voles (Microtus socialis), Tristram's jirds (Meriones tristrami), Cairo spiny mice (Acomys cahirinus), house mice (Mus musculus) and Indian crested porcupines (Hystrix indica) were sampled and screened by molecular and isolation methods. Bartonella-DNA was detected in 46 animals: 9/70 (13%) golden jackals, 2/11 (18%) red foxes, 3/35 (9%) rock hyraxes, 1/3 (33%) southern white-breasted hedgehogs, 5/57 (9%) Cairo spiny mice, 25/43 (58%) Tristram's jirds and 1/6 (16%) house mice. Bartonella rochalimae and B. rochalimae-like were widespread among jackals, foxes, hyraxes and jirds. This report represents the first detection of this zoonotic Bartonella sp. in rock hyraxes and golden jackals. Moreover, DNA of Bartonella vinsonii subsp. berkhoffii, Bartonella acomydis, Candidatus Bartonella merieuxii and other uncharacterized genotypes were identified. Three different Bartonella strains were isolated from Tristram's jirds, and several genotypes were molecularly detected from these animals. Furthermore, this study reports the first detection of Bartonella infection in a southern hedgehog. Our study indicates that infection with zoonotic and other Bartonella species is widespread among wild animals and stresses their potential threat to public health.
Richards, G.A.; Mulchi, C.L.; Hall, J.R.
The increased prevalence of phytotoxic levels of oxidants during inversions in urban regions prompted an evaluation of the sensitivities of turf species to different doses of ozone at several stages of plant development. Warm and cool season turfgrass species and cultivars were exposed in fumigation chambers to various concentrations of ozone then scored for vegetative damage. The warm season entries Meyer zoysiagrass (Zoysia japonica Steud.) and Tufcote bermudagrass (Cynodon doctylon L., Pers.) exhibited greater tolerance to ozone than the cool season entries which included tall fescue (Festuca arundinaceae Schreb), perennial ryegrass (Lolium perenne L.), bentgrass (Agrostic paulustris Huds.), red fescue (Festuca rubra L.), Kentucky bluegrass (Poa pratensis L.), and annual bluegrass (Poa annua L.). The cool season grases which exhibited the highest and lowest tolerance to ozone were Merion Kentucky bluegrass and annual bluegrass, respectively. Increasing the ozone exposure from 3.5 to 7.0 hours/day for 5 days at 0.1 ppM caused twice the level of vegetative damage. As a group, seedlings 9 to 14 days of age exhibited greater susceptibility and uniformity in treatment response than seedlings 66 to 71 days of age to ozone exposures of 0.3 to 0.5 ppM for 3 hours.
GHOLIPOURY, Monireh; REZAI, Hamid Reza; NAMROODI, Somayeh; ARAB KHAZAELI, Fatemeh
Background: This study was conducted to collect informative data on the parasitic infection of wild rodents, emphasizing on finding parasites, which have medical importance to human. Methods: During 2012–2014, a total number of 91 wild rodents were captured from rural areas of Turkmen Sahra, Golestan Province, using handmade traps. Animals were anesthetized, surveyed for any ectoparasite and then their carcasses were carefully dissected for examination of endoparsites. Results: Four species of rodents including Mus musculus (52.75%), Rattus norvegicus (38.46%), Rhombomys opimus (4.40%) and Meriones libycus (4.40%) were captured. Parasitic infestation was detected in 38.5% of sampled rodents. Parasite infestation rates of sampled rodents was Hymenolepis diminuta = 7.7%, Cryptosporidium spp = 6.6%, Trichuris spp.= 5.5%, Cysticercus fasciolaris = 2.20%, Angiostrongylus spp.= 2.20%, Capillaria sp.= 1.09%, Rhipicephalus spp. = 8.70%, Nosopsyllus fasciatus = 1.09%, and Laelaps nuttalli = 3.29%. Among 10 genera/species of identified parasites, at least 8 of them were zoonotic with public health importance. L. nuttalli and N. fasciatus were the only two non-zoonotic detected parasites in this survey. Conclusion: Harboring a wide variety of zoonotic parasites in sampled wild rodents particularly when they live nearby villages, represents a potential risk to native inhabitants. Hence, controlling rodents’ population in residential regions and improving awareness of local people about the risk of disease transmission through rodents seems to be entirely necessary. PMID:28127340
Alagaili, Abdulaziz N; Mohammed, Osama B; Omer, Sawsan A
The gastrointestinal parasites and prevalence of infestation in the Arabian red fox Vulpes vulpes arabica Thomas, were investigated at the King Khalid Wildlife Research Centre (KKWRC) in Thumamah, Riyadh Province, Saudi Arabia. Faecal samples were collected from 58 wild caught foxes while under anaesthesia and examined for gastrointestinal parasites stages. Male and female foxes were infected with three major groups of parasites; cestodes, nematodes, protozoa as well as an acanthocephalan. Faecal analyses revealed that 22 foxes (37.9%) were infected with two different Isospora spp. and three (5.2%) with an undescribed Eimeria sp., 12 (20.7%). Nine individuals (15.5%) harboured hookworms, (Trichosomoides sp.), two (3.5%) were infected with Trichuris sp. (probably Trichuris vulpes) and one individual (1.7%) with Taenia sp. (probably Taenia hydatigena). Carcasses of five male and three female foxes were necropsied. Four of the necropsied carcasses yielded Ancylostoma caninum, two each harboured Pterygodermatitis affinis, T. vulpes and Macracanthorhynchus catalinus, in six foxes Joyeuxiella echinorynchoides was found. Five and four foxes were infected with T. hydatigena and Diplopylidium nölleri, respectively. The possible role of the Arabian red fox as an intercalary host essential for the life cycle of Trichosomoides sp., common to the Libyan jird, Meriones libycus, in particular and the importance of this species as a vector for zoonotic infections and in the spread of other parasites to wild and domestic animals in general is discussed.
Shoukry, Nahla M; El-Naggar, Mostafa H; Darwish, Ahmed B; Soliman, Belal A; El-Sawaf, Bahira M
The distribution of rodents was studied in three different habitats. Seven rodent species were identified: Rattus norvegicus, R. alexandrinus, R. frugivorous, Mus musculus, Acomys russatus, Meriones sacramenti and Gerbillus pyramidum. The species distribution varied with the habitat type. The highest density of rodents was in July and August and the lowest one was in January. However, some species were collected all the year round. The rodents were investigated for the endo- and ecto-parasites. No Leishmania parasites were found. The ectoparasites were: Xenopsylla cheopis, Leptopsylla segnis and Ctenocephalides felis, Polyplax spinulos, Hyalomma dromedarii (nymph) and Echinolaelaps echidninus and Hemolaelaps glassgowi. Ecto-parasites were on rodents all year-round in domestic habitat and peridomestic habitats. In wild one, ecto-parasites activity was from March to December. The rodents' role as reservoir for L. major was experimentally studied. Rodents inoculated with L. major together with hamster and BALB-c mice developed cutaneous lesions. The active lesions, the rodents' ecological habitats and the presence of insect-vector may pave the way to an epidemic zoonotic leishmaniasis role.
Krasnov, B R; Shenbrot, G I; Medvedev, S G; Vatschenok, V S; Khokhlova, I S
We studied flea assemblages on rodents in different habitats of the Ramon erosion cirque in the Negev Desert to examine whether host-habitat relations influence flea spatial distribution. Eleven flea species parasitizing 12 rodent species were recorded. There was significant positive relationship between flea species richness and body mass of the host species; no relationships were found between relative richness of flea assemblage and either the number of habitats occupied by the host species or the size of host geographical range. The differences in pattern of flea parasitism among habitat types within host species were determined by both environmental features of a habitat and the specific pattern of habitat use by rodents. There was replacement of Xenopsylla conformis by Xenopsylla ramesis on Meriones crassus and Gerbillus dasyurus among different habitats. The results of ordination of the flea collections from each individual host demonstrated that the flea assemblages were segregated mainly along 4 axes, which explained 86% of total variance. Each of the ordination axes corresponded with a change in flea species composition. The directions of these changes were (1) among-hosts within a habitat and (2) among-habitats within a host.
Morsy, T A; al Dakhil, M A; el Bahrawy, A F
Cutaneous leishmaniasis caused by Leishmania major (zoonotic, ZCL) and L. tropica (anthroponotic, ACL) is found in most countries of the Eastern Mediterranean Region. Phlebotomus papatasii is the proven vector of L. major and rodents Rhombomys opimus, Psammomys obesus, Meriones spp. and Gerbillus spp. serve as animal reservoirs. Ph. sergenti is the vector of L. tropica in the majority of endemic foci. On the other hand; in the Eastern African highlands (mainly Ethiopia and Kenya), stable foci of L. aethiopica are maintanined by hyraxes and transmitted by Ph. longipes and Ph. pedifer. In this paper, natural Leishmania sp. infection was demonstrated serologically (IHAT) and parasitologically (smear examination) in two out of four rock hyraxes trapped in the highlands of Najran, southern part of the Kingdom. It is concluded that the identity of the Leishmania parasite(s)in such a focus is essential since it has implication in control and treatment. Also, passive case-detection and isolates from man and sandfly in the vicinity of Najran for typing is a must.
Tabbabi, Ahmed; Ghrab, Jamila; Aoun, Karim; Ready, Paul Donald; Bouratbine, Aïda
From 2009 to 2010, 3129 sandflies were caught in CDC light traps placed in various habitats in Ghomrassen, Tataouine governorate, southeast Tunisia, a mixed focus of human cutaneous leishmaniasis caused by Leishmania tropica and Leishmania major. Species diversity was quantified in anthropogenic, semi-anthropogenic and semi-natural locations. Sandflies were identified according to morphological characters and also by the comparative sequence analysis of a fragment of the mitochondrial cytochrome b gene to distinguish between two putative local vectors of L. tropica, namely Phlebotomus chabaudi and Phlebotomus riouxi. The lowest sandfly diversities were found in L. major sites, where the incriminated vector P. papatasi predominated in the burrows of the rodent reservoir hosts (Meriones) as well as inside and outside houses of human cases. In L. tropica sites, the incriminated peri-domestic vector Phlebotomus sergenti was the most abundant species inside houses, whereas P. riouxi or P. chabaudi was the dominant species in the semi-natural rocky habitats favoured by the putative rodent reservoir, Ctenodactylus gundi. All specimens of P. chabaudi identified molecularly had the diagnostic cytochrome b characters of P. riouxi, indicating either that the latter represents only a geographical variant of P. chabaudi or that these two species may sometimes hybridize.
Warburton, Elizabeth M; Khokhlova, Irina S; Dlugosz, Elizabeth M; Der Mescht, Luther Van; Krasnov, Boris R
Parents may alter offspring phenotype depending on the type of environment they encounter. Parasitism is a common stressor; therefore, maternal reproductive investment could change in response to parasitic infection. However, few experiments have investigated the relationship between parasitism and maternal investment, whereas earlier field studies provided contradictory evidence. We investigated number, sex ratio, and growth of offspring in two rodent species, solitary altricial Meriones crassus and social precocial Acomys cahirinus, exposed to parasitism by fleas Xenopsylla ramesis and Parapulex chephrenis. No effect of treatment on litter size or sex ratio of a litter was found in either rodent species. Flea parasitism was found to affect pre-weaning body mass gain in M. crassus, but not in A. cahirinus pups. Furthermore, it appeared that female M. crassus invested resources into their offspring differently in dependence of litter size. In small litters (1-3 offspring), pups from infested females gained more body mass before weaning than pups from uninfested mothers. However, this trend was reversed in females with large litters indicating that parasitized females have a finite amount of resources with which to provision their young. Thus, M. crassus mothers parasitized by fleas seemed to receive some sort of external cues (e.g., stress caused by infestation) that prompted them to alter offspring provisioning, depending on species-specific possibilities and constraints. Therefore, parasites could be a mediator of environmentally induced maternal effects and offspring provisioning may have adaptive value against parasitism.
Morick, Danny; Krasnov, Boris R; Khokhlova, Irina S; Gutiérrez, Ricardo; Fielden, Laura J; Gottlieb, Yuval; Harrus, Shimon
Numerous pathogens are transmitted from one host to another by hematophagous insect vectors. The interactions between a vector-borne organism and its vector vary in many ways, most of which are yet to be explored and identified. These interactions may play a role in the dynamics of the infection cycle. One way to evaluate these interactions is by studying the effects of the tested organism on the vector. In this study, we tested the effects of infection with Bartonella species on fitness-related variables of fleas by using Bartonella sp. strain OE 1-1, Xenopsylla ramesis fleas, and Meriones crassus jirds as a model system. Feeding parameters, including blood meal size and metabolic rate during digestion, as well as reproductive parameters, including fecundity, fertility, and life span, were compared between fleas experimentally infected with Bartonella and uninfected fleas. In addition, the developmental time, sex ratio, and body size of F1 offspring fleas were compared between the two groups. Most tested parameters did not differ between infected and uninfected fleas. However, F1 males produced by Bartonella-positive females were significantly smaller than F1 males produced by Bartonella-negative female fleas. The findings in this study suggest that bartonellae are well adapted to their flea vectors, and by minimally affecting their fitness they have evolved to better spread themselves in the natural environment.
Khokhlova, Irina S; Dlugosz, Elizabeth M; Krasnov, Boris R
We investigated interspecific interactions between two flea species (Parapulex chephrenis and Xenopsylla ramesis) via evaluation of their feeding success (the size of a blood meal and time to death after a single blood meal) when they exploited rodent hosts [Acomys cahirinus (a characteristic host of the former) or Meriones crassus (a characteristic host of the latter)] in single-species or mixed-species groups. We predicted that the negative interactions between the two fleas will result in smaller blood meals and shorter survival time in mixed- versus single-species infestations. We also predicted that the negative effect of mixed-species infestation on feeding performance would be less pronounced when fleas exploited their characteristic host rather than a non-characteristic host. When exploiting a characteristic host, P. chephrenis took larger blood meals in single- than in mixed-species groups, whereas the blood meal size in X. ramesis did not differ between treatments. When exploiting a non-characteristic host, no effect of group composition was found in either flea species. Survival time after a single blood meal was not affected by co-infestation or host species in either flea. Our results suggest context-dependence of the negative effect of co-infestation on feeding performance in fleas with the manifestation of this effect varying in dependence of flea and host species identities.
Morick, Danny; Krasnov, Boris R.; Khokhlova, Irina S.; Gutiérrez, Ricardo; Fielden, Laura J.; Gottlieb, Yuval
Numerous pathogens are transmitted from one host to another by hematophagous insect vectors. The interactions between a vector-borne organism and its vector vary in many ways, most of which are yet to be explored and identified. These interactions may play a role in the dynamics of the infection cycle. One way to evaluate these interactions is by studying the effects of the tested organism on the vector. In this study, we tested the effects of infection with Bartonella species on fitness-related variables of fleas by using Bartonella sp. strain OE 1-1, Xenopsylla ramesis fleas, and Meriones crassus jirds as a model system. Feeding parameters, including blood meal size and metabolic rate during digestion, as well as reproductive parameters, including fecundity, fertility, and life span, were compared between fleas experimentally infected with Bartonella and uninfected fleas. In addition, the developmental time, sex ratio, and body size of F1 offspring fleas were compared between the two groups. Most tested parameters did not differ between infected and uninfected fleas. However, F1 males produced by Bartonella-positive females were significantly smaller than F1 males produced by Bartonella-negative female fleas. The findings in this study suggest that bartonellae are well adapted to their flea vectors, and by minimally affecting their fitness they have evolved to better spread themselves in the natural environment. PMID:23542614
Al-Quraishy, Saleh; Gewik, Mohamed M; Abdel-Baki, Abdel-Azeem S
The present study sought to assess the potential of the cestode Hymenolepis diminuta as a bioindicator for lead accumulation in two industrial areas of the city of Riyadh, Saudi Arabia. Rats (Meriones libycus) were collected from two sites (industrial area II and Salbukh) in Riyadh. In the industrial area II, the mean levels of lead concentrations were found to be 1.96, 1.92, 1.4 and 30.72 μg/g in the rats' liver, kidney and intestine, and in H. diminuta, respectively. In Salbukh, meanwhile, the lead concentrations were 1.63, 1.52, 1.20 and 21.31 μg/g in the rats' liver, kidney, and intestine, and in H. diminuta, respectively. In addition, in industrial area II, compared with the liver, kidney and intestine of their host, the bioconcentration factors of lead were found to be, respectively, 15.6, 16 and 21.9 times higher in H. diminuta, and were 7.5, 8, and 10.2 times higher in the same organs compared to H. diminuta in Salbukh. The present study, therefore, proved that H. diminuta could be used as a bioindicator for heavy metal contamination in the industrial areas of the city of Riyadh.
Rausch, W D; Schallauer, E; Chan, W W; Riederer, P; Weiser, M
Mongolian gerbils of both sexes received a single daily dose of 40 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) over 4 consecutive days. On the fifth day the animals were treated with 15 mg/kg i.p. of L-deprenyl or amantadine or the combination of both drugs. At different time intervals (1, 2, 5 hours) the animals were sacrificed. In the caudate nuclei dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were measured by an HPLC technique. MPTP affected the dopaminergic (HVA -25%) as well as the serotoninergic system (5-HT -54%, 5-HIAA -31%). L-deprenyl and amantadine accumulated DA and 5-HT in the MPTP affected caudates. Synergistic effects of the drug combination could be proven.
Meenderink, Sebastiaan W. F.
Distortion product otoacoustic emissions (DPOAEs) are traditionally evoked by two-tone stimuli. In this study, emission data from Mongolian gerbils are reported that were obtained with stimuli consisting of six to 10 tones. The stimuli were constructed by replacing one of the tones of a tone pair by a narrowband multitone complex. This produced rich spectra of the ear canal sound pressure in which many of the third-order DPOAEs originated from the interaction of triplets of stimulus components. A careful choice of the stimulus frequencies ensured that none of these DPOAE components coincided. Three groups of DPOAEs are reported, two of which are closely related to DPOAEs evoked by tone pairs. The third group has no two-tone equivalent and only arises when using a multitone stimulus. We analyzed the relation between multitone-evoked DPOAEs and DPOAEs evoked by tone pairs, and explored the new degrees of freedom offered by the multitone paradigm. PMID:20838846
Degnan, Andrew P; Tora, George O; Han, Ying; Rajamani, Ramkumar; Bertekap, Robert; Krause, Rudolph; Davis, Carl D; Hu, Joanna; Morgan, Daniel; Taylor, Sarah J; Krause, Kelly; Li, Yu-Wen; Mattson, Gail; Cunningham, Melissa A; Taber, Matthew T; Lodge, Nicholas J; Bronson, Joanne J; Gillman, Kevin W; Macor, John E
Depression is a serious illness that affects millions of patients. Current treatments are associated with a number of undesirable side effects. Neurokinin 1 receptor (NK1R) antagonists have recently been shown to potentiate the antidepressant effects of serotonin-selective reuptake inhibitors (SSRIs) in a number of animal models. Herein we describe the optimization of a biaryl chemotype to provide a series of potent dual NK1R antagonists/serotonin transporter (SERT) inhibitors. Through the choice of appropriate substituents, the SERT/NK1R ratio could be tuned to afford a range of target selectivity profiles. This effort culminated in the identification of an analog that demonstrated oral bioavailability, favorable brain uptake, and efficacy in the gerbil foot tap model. Ex vivo occupancy studies with compound 58 demonstrated the ability to maintain NK1 receptor saturation (>88% occupancy) while titrating the desired level of SERT occupancy (11-84%) via dose selection.
Kretzschmar, Christina; Kalenscher, Tobias; Güntürkün, Onur; Kaernbach, Christian
It is unknown whether birds are able to retain the memory of purely sensory auditory information such as white noise over an extended period of time. In a Pavlovian heart rate conditioning paradigm, four pigeons were trained to associate a mild electric shock with periodic random waveforms, and no shock with aperiodic noise. Periodic waveform detection requires echoic memory, i.e., the online retention of a waveform pattern over a limited time. Starting with 40ms, the waveform period was increased after successful learning until no significant stimulus discrimination could be found. Significant discrimination was achieved at periods of up to 2560ms. This is the first demonstration that echoic memory performance in birds is clearly superior to cats and gerbils, and comparable to naive human performance.
Dietz, Gunnar P H; Bähr, Mathias
Short basic amino acid sequences, often called cell-penetrating peptides (CPPs), allow the delivery of proteins and other molecules into cells and across the blood-brain barrier (BBB). Although the ability of basic proteins to facilitate such trafficking is known for a long time, only the application of genetic methods and overexpression of fusion proteins in Escherichia coli has lead to a wide application of CPP in many research areas, including signal transduction, cancer, angiogenesis, apoptosis, bone development, cardioprotection, cell cycle, neurobiology, and many others. For the neuroscientist, CPPs are particularly attractive, as a number of articles in the last 5 years have reported their use for neuronal rescue in a number of models for neurodegenerative diseases in vitro and in vivo in rats, mice, or gerbils. Here, we give a detailed description of the protein purification methodology and applications in neuroscience.
Sheh, Alexander; Fox, James G
The discovery of Helicobacter pylori overturned the conventional dogma that the stomach was a sterile organ and that pH values < 4 were capable of sterilizing the stomach. H. pylori are an etiological agent associated with gastritis, hypochlorhydria, duodenal ulcers, and gastric cancer. It is now appreciated that the human stomach supports a bacterial community with possibly 100s of bacterial species that influence stomach homeostasis. Other bacteria colonizing the stomach may also influence H. pylori-associated gastric pathogenesis by creating reactive oxygen and nitrogen species and modulating inflammatory responses. In this review, we summarize the available literature concerning the gastric microbiota in humans, mice, and Mongolian gerbils. We also discuss the gastric perturbations, many involving H. pylori, that facilitate the colonization by bacteria from other compartments of the gastrointestinal tract, and identify risk factors known to affect gastric homeostasis that contribute to changes in the microbiota. PMID:23962822
Domenici, Rosaria Maria; Mingfu, Luo; Tebano, Maria Teresa; Reggio, Rosaria; Chiarotti, Flavia; Petti, Filomena; Liguori, Aldo; Popoli, Patrizia
The effects of electroacupuncture (EA) has been studied in a model of global cerebral ischaemia performed in gerbils through the bilateral carotid artery occlusion (BCAO). Animals, under isofluorane anaesthesia, underwent 5 min of BCAO and were killed after 7 days. The effects of EA were evaluated both on functional (with electrophysiological recordings of synaptic potentials in hippocampal slices) and morphological parameters (by counting the number of survived neurons in CA1 area of the hippocampus). The results demonstrated that the treatment of animals with EA (5 min before, during and 20 min after BCAO and 30 min per day in the following 5 days) did not modify either the ischaemia-induced reduction of synaptic potentials amplitude, either ischaemia-induced neuronal loss in the hippocampus. We conclude that, at least in this animal model of cerebral ischaemia, EA does not exert a neuroprotective effect.
Levy, B M
The usual laboratory animals, such as rats and hamsters, may not fit the criteria for an analogue of human periodontal disease, although they may be useful in the study of dental caries. Rats, hamsters, mice, guinea pigs and rabbits have been the animals of choice in studies relating nutritional deficiencies and excesses to the dental and oral tissues. Gerbils, dogs, cats, horses, cows and fowl are useful in the study of mineralized tissues of teeth and bones. Recently, primate analogues have been developed for the study of periodontal diseaes and dental caries, the two most important dental diseases afflicting man. The use of a wide variety of laboratory animals in basic dental research makes it timely to review some of the guidelines for the selection of specific animals for particular diseases.
Reichenbach, Tobias; Stefanovic, Aleksandra; Nin, Fumiaki; Hudspeth, A J
Sound is detected and converted into electrical signals within the ear. The cochlea not only acts as a passive detector of sound, however, but can also produce tones itself. These otoacoustic emissions are a striking manifestation of the cochlea's mechanical active process. A controversy remains of how these mechanical signals propagate back to the middle ear, from which they are emitted as sound. Here, we combine theoretical and experimental studies to show that mechanical signals can be transmitted by waves on Reissner's membrane, an elastic structure within the cochlea. We develop a theory for wave propagation on Reissner's membrane and its role in otoacoustic emissions. Employing a scanning laser interferometer, we measure traveling waves on Reissner's membrane in the gerbil, guinea pig, and chinchilla. The results are in accord with the theory and thus support a role for Reissner's membrane in otoacoustic emissions.
Johnson-Delaney, Cathy A
Nondomesticated species are commonly being kept as companion animals. These include the African pygmy hedgehog (Atelerix albi-ventris), the North American black-tailed prairie dog (Cynomys lu-dovicianus), and exotic rodents such as the degu (Octodon degus)and duprasi or fat-tailed gerbil (Pachyuromys duprasi). Common companion marsupials include the sugar glider (Petaurus breviceps),Bennett's or Tammar (Dama) wallabies (Macropus rufogriseus rufo-griseus and Macropus eugenii, respectively), the Brazilian or South American gray short-tailed opossum (Monodelphis domestica), and the North American Virginia opossum (Didelphis virginiana). Although many of these animals are now bred domestically and are fairly docile when human-raised, they are essentially wild animals and hence have strong instincts to hide illness and pain.
Schulz, Andreas L.; Woldeit, Marie L.; Gonçalves, Ana I.; Saldeitis, Katja; Ohl, Frank W.
Goal directed behavior and associated learning processes are tightly linked to neuronal activity in the ventral striatum. Mechanisms that integrate task relevant sensory information into striatal processing during decision making and learning are implicitly assumed in current reinforcement models, yet they are still weakly understood. To identify the functional activation of cortico-striatal subpopulations of connections during auditory discrimination learning, we trained Mongolian gerbils in a two-way active avoidance task in a shuttlebox to discriminate between falling and rising frequency modulated tones with identical spectral properties. We assessed functional coupling by analyzing the field-field coherence between the auditory cortex and the ventral striatum of animals performing the task. During the course of training, we observed a selective increase of functional coupling during Go-stimulus presentations. These results suggest that the auditory cortex functionally interacts with the ventral striatum during auditory learning and that the strengthening of these functional connections is selectively goal-directed. PMID:26793085
Stanton, Patric K; Potter, Pamela E; Aguilar, Jennifer; Decandia, Maria; Moskal, Joseph R
GLYX-13 (threonine-proline-proline-threonine-amide) is an amidated di-pyrrolidine that acts as a functional partial agonist at the glycine site on N-methyl-D-aspartate glutamate receptors (NMDARs). GLYX-13 can both increase NMDAR conductance at NR2B-containing receptors, and reduce conductance of non-NR2B-containing receptors. Here, we report that GLYX-13 potently reduces delayed (24 h) death of CA1 pyramidal neurons produced by bilateral carotid occlusion in Mongolian gerbils, when administered up to 5 h post-ischemia. GLYX-13 also reduced delayed (24 h) neuronal death of CA1, CA3, and dentate gyrus principal neurons elicited by oxygen/glucose deprivation in in-vitro hippocampal organotypic slice cultures, when applied up to 2 h post-oxygen/glucose deprivation. The glycine site full agonist D-serine completely occluded neuroprotection, indicating that GLYX-13 acts by modulating activation of this site.
Rau, Christoph; Richter, Claus-Peter
At present, imaging of cochlear mechanics at mid-cochlear turns has not been accomplished. Although challenging, this appears possible with partially coherent hard x-rays. The present study shows results from stroboscopic x-ray imaging of a test object at audio frequencies. The vibration amplitudes were quantified. In a different set of experiments, an intact and calcified gerbil temporal bone was used to determine displacements of the reticular lamina, tectorial membrane, and Reissner’s membrane with the Lucas and Kanade video flow algorithm. The experiments validated high frequency x-ray imaging and imaging in a calcified cochlea. The present work is key for future imaging of cochlear micromechanics at a high spatial resolution.
Mann, David A; Colbert, Debborah E; Gaspard, Joseph C; Casper, Brandon M; Cook, Mandy L H; Reep, Roger L; Bauer, Gordon B
Auditory evoked potential (AEP) measurements of two Florida manatees (Trichechus manatus latirostris) were measured in response to amplitude modulated tones. The AEP measurements showed weak responses to test stimuli from 4 kHz to 40 kHz. The manatee modulation rate transfer function (MRTF) is maximally sensitive to 150 and 600 Hz amplitude modulation (AM) rates. The 600 Hz AM rate is midway between the AM sensitivities of terrestrial mammals (chinchillas, gerbils, and humans) (80-150 Hz) and dolphins (1,000-1,200 Hz). Audiograms estimated from the input-output functions of the EPs greatly underestimate behavioral hearing thresholds measured in two other manatees. This underestimation is probably due to the electrodes being located several centimeters from the brain.
Meenderink, Sebastiaan W. F.; van der Heijden, Marcel
Cochlear microphonic potentials were recorded from the Mongolian gerbil in response to low-frequency auditory stimuli. Provided that contamination of the potentials by the phase-locked neurophonic is avoided, these recordings can be interpreted "as if recorded from a single outer hair cell". It is found that the instantaneous I/O-curves resemble the well-known Boltzmann activation curve. The dynamic aspect of the I/O-curves does reveal hysteresis and a level-dependent gain that is not observed in static measures of these curves. We explore a model that simulates CM generation from hair cell populations, but find it inadequate to reproduce the data. Rather, there seem to be fast, adaptive mechanisms probably at the level of the transduction channels themselves.
Myoga, Michael H; Lehnert, Simon; Leibold, Christian; Felmy, Felix; Grothe, Benedikt
Neurons in the medial superior olive (MSO) detect microsecond differences in the arrival time of sounds between the ears (interaural time differences or ITDs), a crucial binaural cue for sound localization. Synaptic inhibition has been implicated in tuning ITD sensitivity, but the cellular mechanisms underlying its influence on coincidence detection are debated. Here we determine the impact of inhibition on coincidence detection in adult Mongolian gerbil MSO brain slices by testing precise temporal integration of measured synaptic responses using conductance-clamp. We find that inhibition dynamically shifts the peak timing of excitation, depending on its relative arrival time, which in turn modulates the timing of best coincidence detection. Inhibitory control of coincidence detection timing is consistent with the diversity of ITD functions observed in vivo and is robust under physiologically relevant conditions. Our results provide strong evidence that temporal interactions between excitation and inhibition on microsecond timescales are critical for binaural processing.