Analysis Of Rodents Research Articles

Effect of Earthing Mats on Sleep Quality in Rats.

Grounding, a therapeutic technique involving direct contact with the earth, has been proposed by various studies to potentially have beneficial effects on pressure, sleep quality, stress, inflammation, and mood. However, the scientific evidence supporting its sedative effects remains incomplete. This study examined the sedative effectiveness of an earthing mat on sleep quality and investigated the underlying neural mechanisms using electroencephalography (EEG) analysis in rodents, focusing on orexin and superoxide dismutase (SOD) levels in the brain. Rats were randomly assigned to four groups: the naïve normal group (Nor), the group exposed to an earthing mat for 7 days (A-7D), the group exposed to an earthing mat for 21 days (A-21D), and the group exposed to an electronic blanket for 21 days (EM). EEG results revealed that the A-21D group exhibited significantly reduced wake time and increased rapid eye movement (REM), non-rapid eye movement (NREM), and total sleep time compared to the Nor group (p < 0.05). Moreover, the A-21D group demonstrated a significant increase in NREM sleep (p < 0.001), REM sleep (p < 0.01), and total sleep time (p < 0.001), along with a decrease in wake time compared to the EM group (p < 0.001). The orexin level in the A-21D group was significantly lower compared to the Nor group (p < 0.01), while SOD1 expression was markedly elevated in the A-21D group compared to the Nor group (p < 0.001). These results suggest that the earthing mat may represent a promising new method for promoting sleep quality and could serve as an effective therapeutic technique.

Gold nanoparticle-enhanced X-ray microtomography of the rodent reveals region-specific cerebrospinal fluid circulation in the brain

Cerebrospinal fluid (CSF) is essential for the development and function of the central nervous system (CNS). However, the brain and its interstitium have largely been thought of as a single entity through which CSF circulates, and it is not known whether specific cell populations within the CNS preferentially interact with the CSF. Here, we develop a technique for CSF tracking, gold nanoparticle-enhanced X-ray microtomography, to achieve micrometer-scale resolution visualization of CSF circulation patterns during development. Using this method and subsequent histological analysis in rodents, we identify previously uncharacterized CSF pathways from the subarachnoid space (particularly the basal cisterns) that mediate CSF-parenchymal interactions involving 24 functional-anatomic cell groupings in the brain and spinal cord. CSF distribution to these areas is largely restricted to early development and is altered in posthemorrhagic hydrocephalus. Our study also presents particle size-dependent CSF circulation patterns through the CNS including interaction between neurons and small CSF tracers, but not large CSF tracers. These findings have implications for understanding the biological basis of normal brain development and the pathogenesis of a broad range of disease states, including hydrocephalus.

Effect of Theobroma cacao L. on the Efficacy and Toxicity of Doxorubicin in Mice Bearing Ehrlich Ascites Carcinoma.

Background and objective: Doxorubicin is a widely used chemotherapeutic agent that causes oxidative stress leading to cardiotoxicity, hepatotoxicity, and nephrotoxicity. In contrast, Theobroma cacao L. has been recorded as an anticancer agent and found to be protective against multiple chemical-induced organ injuries, including heart, liver, and kidney injuries. The present study investigated the possible role of extracts from T. cacao beans for organ-protective effects in doxorubicin-induced toxicity in mice bearing Ehrlich ascites carcinoma (EAC). Methodology: After survival analysis in rodents, cocoa bean extract (COE) was investigated for its efficacy against EAC-induced carcinoma and its organ-protective effect against doxorubicin-treated mice with EAC-induced carcinoma. Results: Significant reductions in EAC and doxorubicin-induced alterations were observed in mice administered the COE, either alone or in combination with doxorubicin. Furthermore, COE treatment significantly increased the mouse survival time, life span percentage, and antioxidant defense system. It also significantly improved cardiac, hepatic, and renal function biomarkers and markers for oxidative stress, and it also reduced doxorubicin-induced histopathological changes. Conclusion: COE acted against doxorubicin-induced organ toxicity; potent antioxidant and anticancer activities were also reflected by the COE itself. The COE may therefore serve as an adjuvant nutraceutical in cancer chemotherapy.

Viral Metagenomics Analysis of Rodents From Two Border Provinces Located in Northeast and Southwest China

ObjectiveWild animal pathogen surveillance will help to understand the next possible pandemic in advance. Rodents, which have close contact with humans, are generally regarded as a key factor for zoonotic disease control. Given the variation in rodent virus composition in diverse ecologies, we conducted a study on the viral infection of rodents of diverse species in different typical environments of Heilongjiang and Yunnan Provinces, located in northeastern and southwestern China, respectively.MethodsViral metagenomics sequencing and bioinformatic analysis were performed to determine the different distributions of rodent-borne viruses in typical environments of Heilongjiang and Yunnan Provinces, China. After viral culture and PCR confirmation, genomic and phylogenetic quantitative analysis was performed on the detected hantaviruses (HVs) and Beilong viruses (BeiVs).ResultsNineteen rodents from three species and 35 rodents from five species of rodents were collected from Heilongjiang and Yunnan Provinces, respectively. Although the number and number of species of rodents trapped in the northeast were fewer than those in the southwest, viruses annotated from rodents in Heilongjiang were more diverse than those in Yunnan. Rodents carried 22 virus families in Heilongjiang and 13 families in Yunnan. Sequences assembled from Rattus norvegicus were annotated to the M, L, and S segments of HV, and all were clustered within the Seoul-type hantavirus (SEOV). There were 2 (R81Q, S698T) and 4 (K153R, M168I, I279S, and R1790K) amino acid site substitutions in M and L compared with the versions in the most homologous strains. Two BeiV isolates from Rattus norvegicus were closely related to BeiV from brown rats in Hong Kong, with high bootstrap values of >90% in the N segment and > 95% in the L segment. They were further clustered with Tailam virus, forming a distinct group in Paramyxoviridae.ConclusionThe rodents from Heilongjiang and Yunnan located in northeast and southwest China, respectively, had different viral spectra, and only one-third (10/32) of virus families were detected in both areas. The predominant viruses were HV and BeiV in the Hantaviridae and Paramyxoviridae families, respectively. Rodent-borne viruses in the same species were similar in different geographic disparate areas owing to their similar close contact with human habitats and human activities. Additional attention should be given to the monitoring of neglected rodent-borne viruses, especially opportunistic viruses with currently low loads.

Post-Stroke Hemiplegic Rodent Evaluation: A Framework for Assessing Forelimb Movement Quality Using Kinematics.

Kinematics is the gold-standard method for measuring detailed joint motions. Recent research demonstrates that post-stroke kinematic analysis in rats reveals reaching abnormalities similar to those seen in humans after stroke. Nonetheless, behavioral neuroscientists have failed to incorporate kinematic methods for assessing movement quality in stroke models. The availability of a user-friendly method to assess multi-segment forelimb kinematics models should greatly increase uptake of this approach. Here, we present a framework for multi-segment forelimb analysis in rodents after stroke. This method greatly enhances the understanding of post-stroke forelimb motor recovery by including several movement quality metrics often used in human clinical work, such as upper-limb linear and angular kinematics, movement smoothness and kinetics, abnormal synergies, and compensations. These metrics may constitute a preclinical surrogate for the Fugl-Meyer assessment of hemiplegic patients. The data obtained using this method are 83 outputs of linear and angular kinematics and kinetics. The outputs also include 24 time series of continuous data, which afford a graphical representation of the kinematics and kinetics of the reaching cycle. We show that post-stroke rodents displayed many features resembling those seen in humans after stroke that are evident only when multi-segment kinematics models are considered. This method expands the knowledge derived from methods constrained to paw movements to a multi-segment forelimb movement quality framework. Moreover, it highlights the need for preclinical work to consider more sensitive measures of sensorimotor impairment and recovery as a means to enhance the interpretation of true recovery and compensation. © 2022 Wiley Periodicals LLC. Basic Protocol: Recording and data analysis of rodents performing the Montoya staircase task.

Improved 3D tracking and automated classification of rodents' behavioral activity using depth-sensing cameras.

Analysis of rodents' behavior/activity is of fundamental importance in many research fields. However, many behavioral experiments still rely on manual scoring, with obvious problems in reproducibility. Despite important advances in video-analysis systems and computational ethology, automated behavior quantification is still a challenge. The need for large training datasets, background stability requirements, and reduction to two-dimensional analysis (impairing full posture characterization), limit their use. Here we present a novel integrated solution for behavioral analysis of individual rats, combining video segmentation, tracking of body parts, and automated classification of behaviors, using machine learning and computer vision methods. Low-cost depth cameras (RGB-D) are used to enable three-dimensional tracking and classification in dark conditions and absence of color contrast. Our solution automatically tracks five anatomical landmarks in dynamic environments and recognizes seven distinct behaviors, within the accuracy range of human annotations. The developed free software was validated in experiments where behavioral differences between Wistar Kyoto and Wistar rats were automatically quantified. The results reveal the capability for effective automated phenotyping. An extended annotated RGB-D dataset is also made publicly available. The proposed solution is an easy-to-use tool, with low-cost setup and powerful 3D segmentation methods (in static/dynamic environments). The ability to work in dark conditions means that natural animal behavior is not affected by recording lights. Furthermore, automated classification is possible with only ~30 minutes of annotated videos. By creating conditions for high-throughput analysis and reproducible quantitative measurements of animal behavior experiments, we believe this contribution can greatly improve behavioral analysis research.

The Use of Percent Change in RR Interval for Data Exclusion in Analyzing 24-h Time Domain Heart Rate Variability in Rodents.

While epidemiological data support the link between reduced heart rate variability (HRV) and a multitude of pathologies, the mechanisms underlying changes in HRV and disease progression are poorly understood. Even though we have numerous rodent models of disease for mechanistic studies, not being able to reliably measure HRV in conscious, freely moving rodents has hindered our ability to extrapolate the role of HRV in the progression from normal physiology to pathology. The sheer number of heart beats per day (>800,000 in mice) makes data exclusion both time consuming and daunting. We sought to evaluate an RR interval exclusion method based on percent (%) change of adjacent RR intervals. Two approaches were evaluated: % change from “either” and “both” adjacent RR intervals. The data exclusion method based on standard deviation (SD) was also evaluated for comparison. Receiver operating characteristic (ROC) curves were generated to determine the performance of each method. Results showed that exclusion based on % change from “either” adjacent RR intervals was the most accurate method in identifying normal and abnormal RR intervals, with an overall accuracy of 0.92–0.99. As the exclusion value increased (% change or SD), the sensitivity (correctly including normal RR intervals) increased exponentially while the specificity (correctly rejecting abnormal RR intervals) decreased linearly. Compared to the SD method, the “either” approach had a steeper rise in sensitivity and a more gradual decrease in specificity. The intersection of sensitivity and specificity where the exclusion criterion had the same accuracy in identifying normal and abnormal RR intervals was 10–20% change for the “either” approach and ∼ 1 SD for the SD-based exclusion method. Graphically (tachogram and Lorenz plot), 20% change from either adjacent RR interval resembled the data after manual exclusion. Finally, overall (SDNN) and short-term (rMSSD) indices of HRV generated using 20% change from “either” adjacent RR intervals as the exclusion criterion were closer to the manual exclusion method with lower subject-to-subject variability than those generated using the 2 SD exclusion criterion. Thus, 20% change from “either” adjacent RR intervals is a good criterion for data exclusion for reliable 24-h time domain HRV analysis in rodents.

Open source code for behavior analysis in rodents.

AimWe have conducted a series of behavioral tests, which cover a broad range of behavioral domains, on various strains of genetically engineered mice. For the behavioral screening, we have been using Image J plugins that we developed for most of the tests in the battery. Our behavioral analysis system with the plugins enables systematic and automated image analysis of behavior. The plugins are freely available on the “Mouse Phenotype Database” website (http://www.mouse-phenotype.org/software.html). Here, we release the source code of the plugins in a Git repository with the aim of promoting their use and expanding their functionality.MethodsWe published the source code of the Image J plugins for behavioral analysis at Git repository (https://github.com/neuroinformatics). The source code for light/dark transition, elevated plus maze, open filed, T‐maze, and fear conditioning tests was made publicly available in the repository.ConclusionsThe source code of the plugins for the behavioral tests as well as the pre‐compiled binaries can be freely obtained. The open source code could promote the development and modification of the plugins for additional behavioral indices in these tests and for other behavioral tests.

Using Optical Coherence Tomography and Optokinetic Response As Structural and Functional Visual System Readouts in Mice and Rats.

Optical coherence tomography (OCT) is a fast, non-invasive, interferometric technique allowing high-resolution retinal imaging. It is an ideal tool for the investigation of processes of neurodegeneration, neuroprotection and neuro-repair involving the visual system, as these often correlate well with retinal changes. As a functional readout, visually evoked compensatory eye and head movements are commonly used in experimental models involving the visual function. Combining both techniques allows a quantitative in vivo investigation of structure and function, which can be used to investigate the pathological conditions or to evaluate the potential of novel therapeutics. A great benefit of the presented techniques is the possibility to perform longitudinal analyses allowing the investigation of dynamic processes, reducing variability and cuts down the number of animals needed for the experiments. The protocol described aims to provide a manual for acquisition and analysis of high quality retinal scans of mice and rats using a low cost customized holder with an option to deliver inhalational anesthesia. Additionally, the proposed guide is intended as an instructional manual for researchers using optokinetic response (OKR) analysis in rodents, which can be adapted to their specific needs and interests.

Cystometric and External Urethral Sphincter Measurements in Awake Rats with Implanted Catheter and Electrodes Allowing for Repeated Measurements.

Lower urinary tract function is mainly assessed by means of cystometric bladder function analysis in rodents. Conventional cystometries are usually performed as terminal analysis under urethane anesthesia. It is well known that anesthetic drugs can influence bladder function. Hence, the aim of this technique is to perform cystometric measurements of the urinary bladder and external urethral sphincter in lightly restrained awake rats. For this purpose, a bladder catheter is implanted into the bladder dome. Subsequently, two electrodes are implanted bilateral to the external urethral sphincter and a ground electrode is sutured to a non-responsive skeletal muscle. The bladder catheter and the three electrodes are finally tunneled subcutaneously to the neck region and affixed to a harness. With this technique, the lower urinary tract can be measured at multiple time points in the same animal to assess lower urinary tract function. The main application of this technique is the follow-up of simultaneous urinary bladder and external urethral sphincter function in awake healthy rats and after induction of a disease or injury. Moreover, subsequent lower urinary tract monitoring can be performed during evaluation of the disease/injury and to monitor treatment efficacy.

Sleep Disturbance and Hyperactivity Detected by Actigraphy in Rats with Allergic Rhinitis or Attention-Deficit Hyperactivity Disorder.

Actigraphy is an easy and noninvasive method used to monitor human ultradian cycles. However, to our knowledge, it has been not applied to experiments with rodents. Therefore, using actigraphy, we assessed the ultradian cycles and behavior of rats. Rats with or without allergic rhinitis wore an actigraphy device, and triaxial acceleration was recorded. The counts that represent physical activity were lower from 8:00 to 20:00 than those from 20:00 to 8:00 in control rats, suggesting that their sleep phase was from 8:00 to 20:00 and their awake phase from 20:00 to 8:00. The counts from 8:00 to 10:00 were significantly higher in allergic rhinitis rats than in control rats (p < 0.01), suggesting the presence of difficulty with sleep induction in rats with allergic rhinitis. The counts from 18:00 to 20:00 were also significantly higher in allergic rhinitis rats than in control rats (p < 0.05), suggesting the presence of early awakening in rats with allergic rhinitis. Moreover, the counts were significantly higher in allergic rhinitis rats than in control rats from 20:00 to 8:00. These results suggest that rats with allergic rhinitis experienced hyperactivity disorder during the daytime. Additionally, hyperreactivity and difficulty with sleep induction were observed in 6-hydroxydopamine-lesioned rats, an animal model of attention-deficit hyperactivity disorder. This study shows for the first time that actigraphy can be successfully used for behavioral analysis in rodents. These rat models could be useful for analyzing the mechanisms involved in sleep disturbances and hyperactivity disorder.

A Non‐invasive Novel Method to Assess Necrotizing Enterocolitis in Rodents

Necrotizing enterocolitis (NEC) is the leading cause of mortality due to gastrointestinal (GI) disease in premature neonates. The precise pathogenesis of NEC is unknown, but early stages are thought to be characterized by damage to the intestinal mucosa and changes to the microbiota; while full intestinal necrosis, perforation, and multi‐system failure occur during the later stages. The early diagnosis of NEC would drastically reduce morbidity and mortality, but there are currently no predictive tests available to clinicians.Heart rate variability (HRV) is a non‐invasive way to measure changes in vagal tone, and our laboratory has shown that the high frequency power spectra, an indicator of vagal tone, is a useful factor to predict NEC in neonates before the onset of clinical symptoms (Doheny et al. Neurogastroenterol. Motil., 2014). Technical issues prevent the same power analysis in rodents; however, time‐domain analysis of HRV analyzes inter‐beat‐interval differences (IBID) to discriminate vagal tone. Our unpublished data indicate a correlation between IBID and GI motility, thus validating the usefulness of cardiac vagal tone measures as a non‐invasive indicator of GI motility (Meister and Travagli, unpublished).In the present work we hypothesize that: i) in rodents IBID is a valid marker of NEC; and, ii) the alterations of the neurochemical phenotype of myenteric and vagal preganglionic neurons are proportional to the severity of NEC.Increasing severity stages of NEC are induced in newborn Sprague‐Dawley rats including i) mild NEC (&lt;Stage 2) through twice daily exposure to cold stress and hypoxia, ii) mild NEC and vagotomy (Stage 2–3), and iii) NEC (Stage 4) through maternal separation and formula feeding in addition to cold stress and hypoxia. Rats underwent HRV measures using bilateral electrodes before and after stress exposure on postnatal days (PD) 1 and 5, before being sacrificed on PD9. Gastrointestinal and brain tissues were fixed and analyzed with H&amp;E (to identify NEC stages) and fluorescence immunohistochemistry (to assess the neurochemical phenotype).Control rats displayed typical developmental increases in IBID, while NEC treatments attenuated this effect. Control and all NEC rat groups showed similar numbers of neurons in the myenteric plexus (MP; PGP 9.5 staining) and similar proportion of choline acetyltransferase immunoreactivity (ChAT) in both the MP and DVC. NEC rats showed increases in nitric oxide synthase immunoreactivity (NOS) in both the MP and DVC. Finally, both mild NEC and NEC rats showed decreases in tyrosine hydroxylase immunoreactivity (TH) in the MP, but increases in the DVC. Data are summarized in the Table below.Our data indicate that: i) NEC rodents had an attenuated IBID, consistent with human HRV data; and, ii) myenteric and vagal preganglionic neurons undergo alterations in the NEC model proportional to the severity of the treatments.We suggest that HRV measures are a promising predictive measure of decreased vagal tone and therefore NEC in rodents. This novel NEC model provides a non‐invasive tool to test the efficacy of preventative experimental measures.Support or Funding InformationNIH DK99350 IBIDPD1 IBIDPD5 PGP 9.5 (neurons/field) ChAT NOS TH (MP: % of total; DVC: neurons/slice) MP MP DVC MP DVC MP DVC ControlN=2–7 1.039 ± 0.106 2.361 ± 0.505* 52 ± 2 67 ± 4 157 ± 16 22 ± 4 5 ± 1 26 ± 11 2 ± 1 Mild NECN=2–7 1.004 ± 0.146 1.300 ± 0.011 48 ± 3 60 ± 1 168 ± 20 31 ± 1 ‐‐‐ 18 ± 5* 40 ± 18* Mild NEC + vagotomyN=2–7 1.161 ± 0.218 1.465 ± 0.171 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ NECN=2–7 ‐‐‐ ‐‐‐ 58 ± 10 56 ± 2 194 ± 19 44 ± 3* 11 ± 4* 10 ± 1* 24 ± 6* p&lt;0.05

Preclinical Evaluation of 18F-PF-05270430, a Novel PET Radioligand for the Phosphodiesterase 2A Enzyme.

The enzyme phosphodiesterase 2A (PF-05270430) is a potential target for development of novel therapeutic agents for the treatment of cognitive impairments. The goal of the present study was to evaluate the PDE2A ligand (18)F-PF-05270430, 4-(3-fluoroazetidin-1-yl)-7-methyl-5-(1-methyl-5-(4-(trifluoromethyl)phenyl)-1H-pyrazol-4-yl)imidazo[1,5-f][1,2,4]triazine, in nonhuman primates. (18)F-PF-05270430 was radiolabeled by 2 methods via nucleophilic substitution of its tosylate precursor. Tissue metabolite analysis in rodents and PET imaging in nonhuman primates under baseline and blocking conditions were performed to determine the pharmacokinetic and binding characteristics of the new radioligand. Various kinetic modeling approaches were assessed to select the optimal method for analysis of imaging data. (18)F-PF-05270430 was synthesized in greater than 98% radiochemical purity and high specific activity. In the nonhuman primate brain, uptake of (18)F-PF-05270430 was fast, with peak concentration (SUVs of 1.5-1.8 in rhesus monkeys) achieved within 7 min after injection. The rank order of uptake was striatum > neocortical regions > cerebellum. Regional time-activity curves were well fitted by the 2-tissue-compartment model and the multilinear analysis-1 (MA1) method to arrive at reliable estimates of regional distribution volume (VT) and binding potential (BPND) with 120 min of scan data. Regional VT values (MA1) ranged from 1.28 mL/cm(3) in the cerebellum to 3.71 mL/cm(3) in the putamen, with a BPND of 0.25 in the temporal cortex and 1.92 in the putamen. Regional BPND values estimated by the simplified reference tissue model (SRTM) were similar to those from MA1. Test-retest variability in high-binding regions (striatum) was 4% ± 6% for MA1 VT, 13% ± 6% for MA1 BPND, and 13% ± 7% SRTM BPND, respectively. Pretreatment of animals with the PDE2A inhibitor PF-05180999 resulted in a dose-dependent reduction of (18)F-PF-05270430 specific binding, with a half maximal effective concentration of 69.4 ng/mL in plasma PF-05180999 concentration. (18)F-PF-05270430 displayed fast and reversible kinetics in nonhuman primates, as well as specific binding blockable by a PDE2A inhibitor. This is the first PET tracer with desirable imaging properties and demonstrated ability to image and quantify PDE2A in vivo.

Striatal Circuits as a Common Node for Autism Pathophysiology.

Autism spectrum disorders (ASD) are characterized by two seemingly unrelated symptom domains—deficits in social interactions and restrictive, repetitive patterns of behavioral output. Whether the diverse nature of ASD symptomatology represents distributed dysfunction of brain networks or abnormalities within specific neural circuits is unclear. Striatal dysfunction is postulated to underlie the repetitive motor behaviors seen in ASD, and neurological and brain-imaging studies have supported this assumption. However, as our appreciation of striatal function expands to include regulation of behavioral flexibility, motivational state, goal-directed learning, and attention, we consider whether alterations in striatal physiology are a central node mediating a range of autism-associated behaviors, including social and cognitive deficits that are hallmarks of the disease. This review investigates multiple genetic mouse models of ASD to explore whether abnormalities in striatal circuits constitute a common pathophysiological mechanism in the development of autism-related behaviors. Despite the heterogeneity of genetic insult investigated, numerous genetic ASD models display alterations in the structure and function of striatal circuits, as well as abnormal behaviors including repetitive grooming, stereotypic motor routines, deficits in social interaction and decision-making. Comparative analysis in rodents provides a unique opportunity to leverage growing genetic association data to reveal canonical neural circuits whose dysfunction directly contributes to discrete aspects of ASD symptomatology. The description of such circuits could provide both organizing principles for understanding the complex genetic etiology of ASD as well as novel treatment routes. Furthermore, this focus on striatal mechanisms of behavioral regulation may also prove useful for exploring the pathogenesis of other neuropsychiatric diseases, which display overlapping behavioral deficits with ASD.

Molecular Survey of Bartonella Species and Yersinia pestis in Rodent Fleas (Siphonaptera) From Chihuahua, Mexico.

Rodent fleas from northwestern Chihuahua, Mexico, were analyzed for the presence of Bartonella and Yersinia pestis. In total, 760 fleas belonging to 10 species were tested with multiplex polymerase chain reaction analysis targeting the gltA (338-bp) and pla genes (478-bp) of Bartonella and Y. pestis, respectively. Although none was positive for Y. pestis, 307 fleas were infected with Bartonella spp., resulting in an overall prevalence of 40.4%. A logistic regression analysis indicated that the presence of Bartonella is more likely to occur in some flea species. From a subset of Bartonella-positive fleas, phylogenetic analyses of gltA gene sequences revealed 13 genetic variants clustering in five phylogroups (I–V), two of which were matched with known pathogenic Bartonella species (Bartonella vinsonii subsp. arupensis and Bartonella washoensis) and two that were not related with any previously described species or subspecies of Bartonella. Variants in phylogroup V, which were mainly obtained from Meringis spp. fleas, were identical to those reported recently in their specific rodent hosts (Dipodomys spp.) in the same region, suggesting that kangaroo rats and their fleas harbor other Bartonella species not reported previously. Considering the Bartonella prevalence and the flea genotypes associated with known pathogenic Bartonella species, we suggest that analysis of rodent and flea communities in the region should continue for their potential implications for human health. Given that nearby locations in the United States have reported Y. pestis in wild animals and their fleas, we suggest conducting larger-scale studies to increase our knowledge of this bacterium.

A Translational Kinetic Analysis of Rodent and Human Hearts Shows Species‐specific Differences and Increases in Monoamine Oxidase Activity with Obesity/Diabetes

Cardiac monoamine oxidase (MAO) has been shown to have an etiological role in heart failure due to the mitochondrial toxicity of the reactive oxygen (ROS) and catechol‐aldehyde species (RCS) produced by this enzyme. A causal role for MAO in cardiomyopathy with obesity and type 2 diabetes has been proposed due to the elevated sympathetic tone that occurs in these conditions, although this has never been investigated in either experimental or clinical models. We performed a cross‐species kinetic analysis of MAO isoform‐specific (A &amp; B) oxidation of dopamine (DA), phenylethylamine (PEA), serotonin (5‐HT), norepinephrine (NE), and Tyramine (TYR) in heart tissue from nondiabetic/control (Ctl) and obese/diabetic (ObD) mice (n=12), rats (n=12), and humans (n=46) using MAO‐derived ROS production as index. In mouse hearts, maximal MAO‐B activity &gt;&gt; MAO‐A, in rat hearts MAO‐A &gt;&gt; MAO‐B, while in humans the isoform activity appears to be equivalent. Maximal MAO activity (both A &amp; B) was significantly higher in ObD mouse and rat hearts with TYR and DA substrates compared with Ctl. ObD mouse hearts also had higher rates of MAO activity with PEA. In human myocardium, MAO activity (both A &amp; B) was 1.5‐fold and 3‐fold higher in ObD patients compared to Ctl patients with NE and DA, respectively. Cardiac MAO‐B activity with 5‐HT also was significantly greater in ObD patients. These translational findings suggest that in obese/diabetic hearts, increased MAO activity and the ROS/RCS derived from it may contribute to cardiomyopathy, and imply that targeting cardiac MAO may have therapeutic potential.

Immuno-Electron Microscopy and Electron Microscopic In Situ Hybridization for Visualizing piRNA Biogenesis Bodies in Drosophila Ovaries.

Immuno-electron microscopy and electron microscopic in situ hybridization are powerful tools to identify the precise subcellular localization of specific proteins and RNAs at the ultramicroscopic level. Here we describe detailed procedures for how to detect the precise location of a specific target labeled with both fluorescence and gold particles. Although they have been developed for the analysis of Drosophila ovarian somatic cells, these techniques are suitable for a wide range of biological applications including human, primate, and rodent analysis.

Oral LD50 toxicity modeling and prediction of per- and polyfluorinated chemicals on rat and mouse

Quantitative structure-activity relationship (QSAR) analyses were performed using the LD(50) oral toxicity data of per- and polyfluorinated chemicals (PFCs) on rodents: rat and mouse. PFCs are studied under the EU project CADASTER which uses the available experimental data for prediction and prioritization of toxic chemicals for risk assessment by using the in silico tools. The methodology presented here applies chemometrical analysis on the existing experimental data and predicts the toxicity of new compounds. QSAR analyses were performed on the available 58 mouse and 50 rat LD(50) oral data using multiple linear regression (MLR) based on theoretical molecular descriptors selected by genetic algorithm (GA). Training and prediction sets were prepared a priori from available experimental datasets in terms of structure and response. These sets were used to derive statistically robust and predictive (both internally and externally) models. The structural applicability domain (AD) of the models were verified on 376 per- and polyfluorinated chemicals including those in REACH preregistration list. The rat and mouse endpoints were predicted by each model for the studied compounds, and finally 30 compounds, all perfluorinated, were prioritized as most important for experimental toxicity analysis under the project. In addition, cumulative study on compounds within the AD of all four models, including two earlier published models on LC(50) rodent analysis was studied and the cumulative toxicity trend was observed using principal component analysis (PCA). The similarities and the differences observed in terms of descriptors and chemical/mechanistic meaning encoded by descriptors to prioritize the most toxic compounds are highlighted.

Evaluation of a Quantitative Magnetic Resonance Imaging System for Whole Body Composition Analysis in Rodents

We evaluated the EchoMRI-900 combination rat and mouse quantitative magnetic resonance (QMR) body composition method in comparison to traditional whole-body chemical carcass composition analysis (CCA) for measurements of fat and fat-free mass in rodents. Live and postmortem (PM) QMR fat and lean mass measurements were obtained for lean, obese and outbred strains of rats and mice, and compared with measurements obtained using CCA. A second group of rats was measured before and after 18 h food or water deprivation. Significant positive correlations between QMR and CCA fat and lean mass measurements were shown for rats and mice. Although all live QMR fat and lean measurements were more precise than CCA for rats, values obtained for mice significantly differed from CCA for lean mass only. QMR performed PM slightly overestimated fat and lean values relative to live QMR but did not show lower precision than live QMR. Food deprivation reduced values for both fat and lean mass; water deprivation reduced estimates of lean mass only. In summary, all measurements using this QMR system were comparable to those obtained by CCA, but with higher overall precision, similar to previous reports for the murine QMR system. However, PM QMR measurements slightly overestimated live QMR values, and lean and fat mass measurements in this QMR system are influenced by hydration status and animal size, respectively. Despite these caveats, we conclude that the EchoMRI QMR system offers a fast in vivo method of body composition analysis, well correlated to but with greater overall precision than CCA.

The structure and evolution of the MaSMC4 gene of common vole Microtus arvalis (Arvicolidae, Rodentia)

In eukaryotes, the SMC (Structural Maintenance of Chromosomes) gene family is represented by at least six genes. Some of these genes have tissue-specific homologs. Eukaryotic SMC structural proteins are the members of biochemical complexes responsible for cohesion of sister chromatids, recombination, repair, regulation of gene expression, and formation of mitotic chromosomes. In the present study, the structure of the SMC4 sub-family gene was examined in common vole Microtus arvalis. Comparative analysis of rodent (M. arvalis, Mus musculus. and Rattus norvegicus), human, and Xenopus SMC4 orthologous genes was carried out, and the main patterns of their organization and regulation were established. The SMC4 genes contain 24 exons; open reading frame starts at exon 2. The SMC4 5' regions contain the CpG islands, extending in the region of exon-intron I and exon 2. The SMC4 genes are characterized by the presence of multiple transcription startpoints. The region of the major transcription startpoint contains the INR CCA,1TTTT element. The SMC4 5' region is characterized by the presence of putative binding site for basal transcription factor Sp and factor E2F, typical of the genes induced in the G I/S phase of the cell cycle. The divergence level of the SMC4 coding region was examined. The mean Ka/Ks ratio for the SMC4 genes examined was 0. 123. The region of exon 2 was found to be the most variable (Ka/Ks = 0.715), while the most conservative was the region coding for the C-globular domain, which contained the DA box (Ka/Ks = 0.024).