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Takashi Ikeda, Kenta Uchida, Yukiko Matsuura, Hiroshi Takahashi, Tsuyoshi Yoshida, Koichi Kaji, Itsuro Koizumi
The activity patterns of mammals are generally categorized as nocturnal, diurnal, crepuscular (active at twilight), and cathemeral (active throughout the day). These patterns are highly variable across regions and seasons even within the same species. However, quantitative data is still lacking, particularly for sympatric species. We monitored the seasonal and diel activity patterns of terrestrial mammals in Hokkaido, Japan. Through an intensive camera-trap survey a total of 13,279 capture events were recorded from eight mammals over 20,344 camera-trap days, i...
2016: PloS One
Lynn M Osikowicz, Sarah A Billeter, Maria Fernanda Rizzo, Michael P Rood, Ashley N Freeman, Joseph E Burns, Renjie Hu, Phalasy Juieng, Vladimir Loparev, Michael Kosoy
We investigated the prevalence of Bartonella washoensis in California ground squirrels (Otospermophilus beecheyi) and their fleas from parks and campgrounds located in seven counties of California. Ninety-seven of 140 (69.3%) ground squirrels were culture positive and the infection prevalence by location ranged from 25% to 100%. In fleas, 60 of 194 (30.9%) Oropsylla montana were found to harbor Bartonella spp. when screened using citrate synthase (gltA) specific primers, whereas Bartonella DNA was not found in two other flea species, Hoplopsyllus anomalus (n = 86) and Echidnophaga gallinacea (n = 6)...
October 5, 2016: Vector Borne and Zoonotic Diseases
Cory T Williams, Kathryn Wilsterman, Victor Zhang, Jeanette Moore, Brian M Barnes, C Loren Buck
The sexes differ in how and when they allocate energy towards reproduction, but how this influences phenotypic plasticity in daily activity patterns is unclear. Here, we use collar-mounted light loggers and triaxial accelerometers to examine factors that affect time spent above ground and overall dynamic body acceleration (ODBA), an index of activity-specific energy expenditure, across the active season of free-living, semi-fossorial arctic ground squirrels (Urocitellus parryii). We found high day-to-day variability in time spent above ground and ODBA with most of the variance explained by environmental conditions known to affect thermal exchange...
September 2016: Royal Society Open Science
Ruiqi Wu, Langting Su, Pai-Feng Yang, Li Min Chen
Reactivation of deafferented cortex plays a key role in mediating the recovery of lost functions, although the precise mechanism is not fully understood. This study simultaneously characterized the dynamic spatiotemporal features of tactile responses in areas 3b and 1 before and 6-8 weeks after partial dorsal column lesion (DCL), and examined how the reactivation relates to the recovery of simple hand use in squirrel monkeys. A combination of high spatiotemporal resolution functional intrinsic optical imaging, microelectrode mapping, behavioral assessment, and tracer histology methods were used...
September 2016: ENeuro
Lei Deng, Wei Li, Xingming Yu, Chao Gong, Xuehan Liu, Zhijun Zhong, Na Xie, Shuangshuang Lei, Jianqiu Yu, Hualin Fu, Hongwei Chen, Huailiang Xu, Yanchun Hu, Guangneng Peng
Enterocytozoon bieneusi is a common opportunistic pathogen causing diarrhea and enteric disease in a variety of animal hosts. Although it has been reported in many animals, there is no published information available on the occurrence of E. bieneusi in red-bellied tree squirrels. To understand the occurrence, genetic diversity, and zoonotic potential of E. bieneusi in red-bellied tree squirrels, 144 fecal specimens from Sichuan province, China, were examined by PCR amplification and sequencing of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene of E...
2016: PloS One
Yingying Han, Jinqi Zhan, Ying Xu, Fengwei Zhang, Zhengrong Yuan, Qiang Weng
The aim of the present study was to elucidate the regulatory role of cell proliferation and apoptosis in testicular development of wild Daurian ground squirrels during the breeding season (April), the non-breeding season (June) and before hibernation (September). Gross mass and hormonal analysis showed that the testis:body mass ratio and plasma testosterone concentration fluctuated seasonally, with a peak in April and lowest values in June. Similarly, spermatogenesis was fully developed in April but suppressed in June and September...
September 28, 2016: Reproduction, Fertility, and Development
Kayla Huemer, Jayne M Squirrell, Robert Swader, Danny C LeBert, Anna Huttenlocher, Kevin W Eliceiri
Zebrafish, an established model organism in developmental biology, is also a valuable tool for imaging wound healing in space and time with cellular resolution. However, long-term imaging of wound healing poses technical challenges as wound healing occurs over multiple temporal scales. The traditional strategy of larval encapsulation in agarose successfully limits sample movement but impedes larval development and tissue regrowth and is therefore not amenable to long-term imaging of wound healing. To overcome this challenge, we engineered a functionally compartmentalized device, the zebrafish Wounding and Entrapment Device for Growth and Imaging (zWEDGI), to orient larvae for high-resolution microscopy, including confocal and second harmonic generation (SHG), while allowing unrestrained tail development and regrowth...
September 27, 2016: Zebrafish
Long Xing Fan, En Qi Wu, Jun Liu, Xiao Chen Qu, Chao Liu, Bao An Ning, Ying Liu
Plague is a virulent infectious disease in China. In this study, '3S' technology was used to perform spatial autocorrelation analysis and spatial interpolation analysis for Spermophilus dauricus (S. Dauricus, a species of ground squirrel) captured in Manchuria City in 2015. The results were visually inspected. During the two-month (May to July) plague surveillance in 2015, 198 S. dauricus individuals were captured in the study area in Manchuria City (48 monitoring areas) by using a day-by-day catching method...
August 2016: Biomedical and Environmental Sciences: BES
Seongjun Choe, Dongmin Lee, Hansol Park, Hyeong-Kyu Jeon, Youngsun Lee, Ki-Jeong Na, In-Yong Lee, Keeseon S Eom
Parasites are recorded from the red squirrel, Sciurus vulgaris, from Cheongju, the Republic of Korea. A total of 5 road-killed squirrels were thoroughly examined for internal and external parasites from November 2011 to May 2014. Total 4 parasite species, including 1 tapeworm and 3 ectoparasite species were recovered. They were morphologically identified as Catenotaenia dendritica (Cestoda: Catenotaeniidae), Hirstionyssus sciurinus, Leptotrombidium pallidum, and Ceratophyllus (Monopsyllus) indages. Among them, C...
August 2016: Korean Journal of Parasitology
Willem J Laursen, Eve R Schneider, Dana K Merriman, Sviatoslav N Bagriantsev, Elena O Gracheva
The ability to sense heat is crucial for survival. Increased heat tolerance may prove beneficial by conferring the ability to inhabit otherwise prohibitive ecological niches. This phenomenon is widespread and is found in both large and small animals. For example, ground squirrels and camels can tolerate temperatures more than 40 °C better than many other mammalian species, yet a molecular mechanism subserving this ability is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal ion channel involved in the detection of noxious thermal and chemical stimuli by primary afferents of the somatosensory system...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
Jeffery R Werner, Elizabeth A Gillis, Rudy Boonstra, Charles J Krebs
Throughout much of North America's boreal forest, the cyclical fluctuations of snowshoe hare populations (Lepus americanus) may cause other herbivores to become entrained in similar cycles. Alternating apparent competition via prey switching followed by positive indirect effects are the mechanisms behind this interaction. Our purpose is to document a change in the role of indirect interactions between sympatric populations of hares and arctic ground squirrels (Urocitellus parryii plesius), and to emphasize the influence of predation for controlling ground squirrel numbers...
2016: PeerJ
E P Hoberg, A A Makarikov, V V Tkach, S Meagher, T N Nims, R P Eckerlin, K E Galbreath
Synoptic data and an understanding of helminth parasite diversity among diverse rodent assemblages across temperate latitudes of North America remain remarkably incomplete. Renewed attention to comprehensive survey and inventory to establish the structure of biodiverse faunas is essential in providing indicators and proxies for identifying the outcomes of accelerating change linked to climate warming and anthropogenic forcing. Subsequent to the description of Hymenolepis folkertsi in the oldfield mouse, Peromyscus polionotus, additional specimens of hymenolepidids were collected or discovered in archived museum repositories from multiple species of deer mice (Peromyscus maniculatus, Peromyscus leucopus), the golden mouse (Ochrotomys nuttalli), chipmunks (Tamias striatus, Tamias amoenus), the 13-lined ground squirrel (Ictidomys tridecemlineatus), and tree squirrels (Sciurus carolinensis, Sciurus niger) from disjunct localities in the USA spanning southern Georgia, Virginia, Pennsylvania, Connecticut, the Upper Peninsula of Michigan, Wisconsin, and central Idaho...
September 14, 2016: Parasitology Research
Samantha M Logan, Kenneth B Storey
Mammalian hibernation is characterized by a general suppression of energy expensive processes and a switch to lipid oxidation as the primary fuel source. Glucose-responsive carbohydrate responsive element binding protein (ChREBP) has yet to be studied in hibernating organisms, which prepare for the cold winter months by feeding until they exhibit an obesity-like state that is accompanied by naturally-induced and completely reversible insulin resistance. Studying ChREBP expression and activity in the hibernating 13-lined ground squirrel is important to better understand the molecular mechanisms that regulate energy metabolism under cellular stress...
October 2016: Cryobiology
Tomokazu Kawashima, Richard W Thorington, Paula W Bohaska, Fumi Sato
A long-standing issue in squirrel evolution and development is the origin of the styliform cartilage of flying squirrels, which extends laterally from the carpus to support the gliding membrane (patagium). Because the styliform cartilage is one of the uniquely specialized structures permitting gliding locomotion, the knowledge of its origin and surrounding transformation is key for understanding their aerodynamic evolution. The developmental study that would definitely answer this question would be difficult due to the rarity of embryological material...
September 9, 2016: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
R David, A Stoessel, A Berthoz, F Spoor, D Bennequin
The semicircular duct system is part of the sensory organ of balance and essential for navigation and spatial awareness in vertebrates. Its function in detecting head rotations has been modelled with increasing sophistication, but the biomechanics of actual semicircular duct systems has rarely been analyzed, foremost because the fragile membranous structures in the inner ear are hard to visualize undistorted and in full. Here we present a new, easy-to-apply and non-invasive method for three-dimensional in-situ visualization and quantification of the semicircular duct system, using X-ray micro tomography and tissue staining with phosphotungstic acid...
2016: Scientific Reports
Steven Heritage, David Fernández, Hesham M Sallam, Drew T Cronin, José Manuel Esara Echube, Erik R Seiffert
The "scaly-tailed squirrels" of the rodent family Anomaluridae have a long evolutionary history in Africa, and are now represented by two gliding genera (Anomalurus and Idiurus) and a rare and obscure genus (Zenkerella) that has never been observed alive by mammalogists. Zenkerella shows no anatomical adaptations for gliding, but has traditionally been grouped with the glider Idiurus on the basis of craniodental similarities, implying that either the Zenkerella lineage lost its gliding adaptations, or that Anomalurus and Idiurus evolved theirs independently...
2016: PeerJ
Yichi Zhang, Oscar A Aguilar, Kenneth B Storey
Background. Mammalian hibernation in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is characterized by dramatic changes on a physiological and molecular level. During hibernation, mammalian hearts show a propensity to hypertrophy due to the need for increasing contractility to pump colder and more viscous blood. While cardiac hypertrophy is quite often a process characterized by decompensation, the ground squirrel studied is an excellent model of cardiac plasticity and cardioprotection under conditions of hypothermia and ischemia...
2016: PeerJ
A A Lakhina, L N Markevich, N M Zakharova, V N Afanasyev, I K Kolomiytseva, E E Fesenko
In hibernating Yakutian ground squirrels S. undulatus, the content of total phospholipids in the nuclei of liver increased by 40% compared to that in animals in summer. In torpid state, the amount of sphingomyelin increased almost 8 times; phosphatidylserine, 7 times; and cardiolipin, 4 times. In active "winter" ground squirrels, the amount of sphingomyelin, phosphatidylserine, and cardiolipin decreased compared to the hibernating individuals but remained high compared to the "summer" ones. The torpor state did not affect the amount of lysophosphatidylcholine and phosphatidylinositol...
July 2016: Doklady. Biochemistry and Biophysics
Yichi Zhang, Shannon N Tessier, Kenneth B Storey
Foxo4 and MyoG proteins regulate the transcription of numerous genes, including the E3 ubiquitin ligases MAFbx and MuRF1, which are activated in skeletal muscle under atrophy-inducing conditions. In the thirteen-lined ground squirrel, there is little muscle wasting that occurs during hibernation, a process characterized by bouts of torpor and arousal, despite virtual inactivity. Consequently, we were interested in studying the regulatory role of Foxo4 and MyoG on ubiquitin ligases throughout torpor-arousal cycles...
October 2016: Cryobiology
Rita Gomes Rocha, Yuri Luiz Reis Leite, Leonora Pires Costa, Danny Rojas
The family Sciuridae is one of the most widespread and ecologically diverse lineage of rodents and represents an ideal model for investigating the evolution of locomotion modes and the historical biogeography of terrestrial mammals. We used a comprehensive database on locomotion modes, an updated phylogeny and novel biogeographic comparative methods to re-assess the evolution of locomotion of squirrels and to investigate if these locomotion modes evolved convergently in different continents. We found that locomotion changes occurred in different independent lineages of the family, including four reversals to terrestriality and one evolution of gliding...
September 3, 2016: Journal of Evolutionary Biology
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