Aquilegia, Vol. 35 No. 4, Winter 2011: Newsletter of the Colorado Native Plant Society

https://epublications.regis.edu/aquilegia/1109/thumbnail.jp

Somatostatin Serves a Modulatory Role in the Mouse Olfactory Bulb: Neuroanatomical and Behavioral Evidence

Somatostatin (SOM) and somatostatin receptors (SSTR1–4) are present in all olfactory structures, including the olfactory bulb (OB), where SOM modulates physiological gamma rhythms and olfactory discrimination responses. In this work, histological, viral tracing and transgenic approaches were used to characterize SOM cellular targets in the murine OB. We demonstrate that SOM targets all levels of mitral dendritic processes in the OB with somatostatin receptor 2 (SSTR2) detected in the dendrites of previously uncharacterized mitral-like cells. We show that inhibitory interneurons of the glomerular layer (GL) express SSTR4 while SSTR3 is confined to the granule cell layer (GCL). Furthermore, SOM cells in the OB receive synaptic inputs from olfactory cortical afferents. Behavioral studies demonstrate that genetic deletion of SSTR4, SSTR2 or SOM differentially affects olfactory performance. SOM or SSTR4 deletion have no major effect on olfactory behavioral performances while SSTR2 deletion impacts olfactory detection and discrimination behaviors. Altogether, these results describe novel anatomical and behavioral contributions of SOM, SSTR2 and SSTR4 receptors in olfactory processing

Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.

BACKGROUND: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development. RESULTS: The genome has been sequenced to 2 × coverage using Sanger sequencing, enhanced with additional next generation sequencing and the integration of extensive physical and linkage maps to build the genome assembly. We also sequenced the tammar transcriptome across many tissues and developmental time points. Our analyses of these data shed light on mammalian reproduction, development and genome evolution: there is innovation in reproductive and lactational genes, rapid evolution of germ cell genes, and incomplete, locus-specific X inactivation. We also observe novel retrotransposons and a highly rearranged major histocompatibility complex, with many class I genes located outside the complex. Novel microRNAs in the tammar HOX clusters uncover new potential mammalian HOX regulatory elements. CONCLUSIONS: Analyses of these resources enhance our understanding of marsupial gene evolution, identify marsupial-specific conserved non-coding elements and critical genes across a range of biological systems, including reproduction, development and immunity, and provide new insight into marsupial and mammalian biology and genome evolution

Validation of a novel device to measure and provide feedback on sedentary behavior

Purpose. Pedometers, which enable self-monitoring of step counts, are effective in facilitating increases in physical activity. Similar devices which provide real-time feedback on sedentary (sitting) behavior are limited. This study aimed to develop and validate a novel device – the SitFIT – which could accurately measure and provide feedback on sedentary behavior and physical activity. Methods. The SitFIT is a tri-axial accelerometer, developed by PAL Technologies, which is worn in the front trouser pocket. This enables tracking of thigh inclination and therefore differentiation between sitting and upright postures, as well as tracking of step count. It has a display to provide user feedback. To determine the validity of the SitFIT for measuring sedentary behavior and step counts, 21 men, aged 30-65 years, with body mass index 26.6±3.9 kg.m-2 wore a SitFIT in a front trouser pocket and an activPAL accelerometer attached to their thigh for up to seven days. Outputs from the SitFIT were compared with the activPAL, which was assumed to provide gold-standard measurements of sitting and step counts. Results. Mean step counts were ~4% lower with the SitFIT than activPAL, with correlation between the two methods being very high (r=0.98) and no obvious bias from the line of equality (regression line: y=1.0035x+418.35). Mean sedentary time was ~5% higher with the SitFIT than activPAL, correlation between methods was high (r=0.84) and the equation of the regression line was close to the line of equality (y=0.8728x+38.445). Conclusions. The SitFIT has excellent validity for measurement of free-living step counts and sedentary time and therefore addresses a clear need for a device that can be used as a tool to provide feedback on sedentary behavior to facilitate behavior change

The vomeronasal organ and the role of pheromones in the reproduction of the tammar wallaby, Macropus eugenii

© 2008 Dr. Nanette Yvette SchneiderOdours are important for successful reproduction. The main olfactory system is responsible for smell detection but the vomeronasal system (VS) can detect sexual pheromones. This study investigated the development and function of both systems in the tammar using morphological, physiological, behavioural and genetic approaches. Male tammars had a well developed VS that appears to detect the reproductive state of females. Both olfactory systems are functional at birth and odours appear to guide the young to the pouch

Olfactory Perception

International audienc

Correspondence: In reply to the correspondence by Jing‐Zhan Wu and Chun‐Hai Tang

International audienceIn reply to the correspondence “A combination of sectional micro-anatomy and micro-stereoscopic anatomy is an improved micro-dissection method” by Jing-Zhan Wu and Chun-Hai Tang: We agree with the authors that it is important to collect data using diverse techniques (two and three dimensional) for the best possible understanding of a species' brain structure.The authors speak of “discrepancies,” especially concerning the shape and size of cerebral ventricles, between their study (Wu et al. 2021) conducted on 40-day-old (juvenile) rabbits and our study on 4-day-old (newborn) rabbits (Schneider et al. 2018). They also mention differences observed in the brain of adult rabbits studied by Shek et al. (1986). These are differences, not “discrepancies”, and they are not surprising because the brain changes shape during development, especially in the size and shape of the ventricles (e.g. Scelsi et al. 2020). These same changes occur in rabbits. Most importantly, shortly after birth, the brain of the newborn rabbit changes very rapidly – indeed, we observed clear differences between neonates (0-day-old) (Schneider et al. 2016) and 4-day-old rabbit pups (Schneider et al. 2018). Therefore, it is important that Wu et al. 2021 compare literature describing brain sections of 40-day-old rabbits, or extend their own studies to the brain of 4-day-old rabbit pups, to get a clear understanding of any differences observed. Such differences might not be due to different techniques

Spontaneous brain processing of the mammary pheromone in rabbit neonates prior to milk intake

International audienceChemical signals play a critical role in interindividual communication, including mother-young relationships. Detecting odor cues released by the mammary area is vital to the newborn's survival. European rabbit females secret a mammary pheromone (MP) in their milk, which releases sucking related orocephalic movements in newborns. Pups spontaneously display these typical movements at birth, independently of any perinatal learning. Our previous Fos mapping study (Charra et al., 2012) performed in 4-day-old rabbits showed that the MP activated a network of brain regions involved in osmoregulation, odor processing and arousal in comparison with a control odor. However, at this age, the predisposed appetitive value of the MP might be reinforced by previous milk intake. Here, the brain activation induced by the MP was examined by using Fos immunocytochemistry and compared to a neutral control odor in just born pups (day 0) that did not experienced milk intake. Compared to the control odor, the MP induced an increased Fos expression in the posterior piriform cortex. In the lateral hypothalamus, Fos immunostaining was combined with orexin detection since this peptide is involved in arousal/food-seeking behavior. The number of double-labeled cells was not different between MP and control odor stimulations but the total number of Fos stained cells was increased after MP exposure. Our results indicate that the MP does not activate the same regions in 0- vs. 4-day-old pups. This difference between the two ages may reflect a changing biological value of the MP in addition to its constant predisposed releasing value. (C) 2016 Elsevier B.V. All rights reserved

Corrélats cérébraux de la perception synthétique d'un mélange d'odorants chez le lapin nouveau-né

Résumé de posterA chaque étape du développement, les organismes sont confrontés à de très nombreux odorants, présents le plus souvent en mélanges. Il leur faut simplifier ce volume d’informations pour se focaliser sur les plus pertinentes biologiquement. La perception synthétique des mélanges, c’est-à-dire l’attribution à un mélange d’une odeur distincte de celles de ses constituants, peut contribuer à cela. Ici, nous avons étudié cette perception au niveau cérébral en utilisant comme modèle le nouveau-né lapin. Nous savions en effet qu’après conditionnement à l’éthyl maltol (odorant A), les lapereaux ne répondent ni à l’isobutyrate d’éthyle (odorant B) ni au mélange AB (ratio 70/30) de ces odorants; en revanche, ils répondent au mélange A’B’ (ratio 32/68 des mêmes odorants). Le mélange AB semble ainsi perçu de manière synthétique alors que le mélange A’B’ le serait de façon analytique (reconnaissance des constituants). L’activation cérébrale engendrée par AB et A’B’ a été étudiée par immunohistochimie de la protéine Fos chez des lapereaux de 4 jours après conditionnement à A. Les premières analyses des bulbes olfactifs suggèrent une hétérogénéité de l’expression de Fos entre AB et A’B’. Au niveau des régions centrales, le mélange A’B’ engendre, comparativement à AB, des activations plus prononcées du cortex piriforme antérieur et postérieur, de la ténia tecta, de l’amygdale basale et médiale, de l’hippocampe ventral et du noyau paraventriculaire du thalamus antérieur. Ainsi, de mêmes odorants activent le cerveau néonatal de manière différente selon que leur mélange est traité de façon analytique ou synthétique, en lien avec une réponse comportementale contrastée