scholarly journals Insecticide exposure during brood or early-adult development reduces brain growth and impairs adult learning in bumblebees

2020 ◽  
Vol 287 (1922) ◽  
pp. 20192442 ◽  
Author(s):  
Dylan B. Smith ◽  
Andres N. Arce ◽  
Ana Ramos Rodrigues ◽  
Philipp H. Bischoff ◽  
Daisy Burris ◽  
...  
Keyword(s):  
Adult Development ◽  
Early Stage ◽  
Nervous System Development ◽  
Learning Performance ◽  
Lower Probability ◽  
Similar Degree ◽  
Micro Computed Tomography ◽  
Olfactory Conditioning ◽  
Social Bees ◽  
Computed Tomography Scanning

For social bees, an understudied step in evaluating pesticide risk is how contaminated food entering colonies affects residing offspring development and maturation. For instance, neurotoxic insecticide compounds in food could affect central nervous system development predisposing individuals to become poorer task performers later-in-life. Studying bumblebee colonies provisioned with neonicotinoid spiked nectar substitute, we measured brain volume and learning behaviour of 3 or 12-day old adults that had experienced in-hive exposure during brood and/or early-stage adult development. Micro-computed tomography scanning and segmentation of multiple brain neuropils showed exposure during either of the developmental stages caused reduced mushroom body calycal growth relative to unexposed workers. Associated with this was a lower probability of responding to a sucrose reward and lower learning performance in an olfactory conditioning test. While calycal volume of control workers positively correlated with learning score, this relationship was absent for exposed workers indicating neuropil functional impairment. Comparison of 3- and 12-day adults exposed during brood development showed a similar degree of reduced calycal volume and impaired behaviour highlighting lasting and irrecoverable effects from exposure despite no adult exposure. Our findings help explain how the onset of pesticide exposure to whole colonies can lead to lag-effects on growth and resultant dysfunction.

scholarly journals Engineering and Manufacturing Technology of Green Epoxy Resin Coatings Modified with Recycled Fine Aggregates

2021 ◽  
Author(s):  
Kamil Krzywiński ◽  
Łukasz Sadowski ◽  
Damian Stefaniuk ◽  
Aleksei Obrosov ◽  
Sabine Weiß
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Construction And Demolition Waste ◽  
Fine Aggregate ◽  
Micro Computed Tomography ◽  
Demolition Waste ◽  
Replacement Ratio ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Computed Tomography Scanning

AbstractNowadays, the recycled fine aggregate sourced from construction and demolition waste is not frequently used in manufacturing of epoxy resin coatings. Therefore, the main novelty of the article is to prepare green epoxy resin coatings modified with recycled fine aggregate in a replacement ratio of natural fine aggregate ranged from 20 to 100%. The microstructural properties of the aggregates and epoxy resin were analyzed using micro-computed tomography, scanning electron microscopy and nanoindentation. The macroscopic mechanical properties were examined using pull-off strength tests. The highest improvement of the mechanical properties was observed for epoxy resin coatings modified with 20% of natural fine aggregate and 80% of recycled fine aggregate. It has been found that even 100% of natural fine aggregate can be successfully replaced using the recycled fine aggregate with consequent improvement of the pull-off strength of analyzed epoxy resin coatings. In order to confirm the assumptions resulting from the conducted research, an original analytical and numerical failure model proved the superior behavior of modified coating was developed.

scholarly journals Bone Regeneration Capacity of Newly Developed Uncalcined/Unsintered Hydroxyapatite and Poly-l-lactide-co-glycolide Sheet in Maxillofacial Surgery: An In Vivo Study

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 22
Author(s):  
Huy Xuan Ngo ◽  
Quang Ngoc Dong ◽  
Yunpeng Bai ◽  
Jingjing Sha ◽  
Shinji Ishizuka ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Reconstructive Surgery ◽  
Early Stage ◽  
Maxillofacial Surgery ◽  
Male Rats ◽  
Regeneration Ability ◽  
Sprague Dawley ◽  
Micro Computed Tomography ◽  
Rat Mandible

Uncalcined/unsintered hydroxyapatite and poly-l-lactide-co-glycolide (u-HA/PLLA/PGA) is a new bioresorbable nanomaterial with superior characteristics compared with current bioresorbable materials, including appropriate mechanical properties, outstanding bioactive/osteoconductive features, and remarkably shorter resorption time. Nevertheless, the bone regeneration characteristics of this nanomaterial have not been evaluated in maxillofacial reconstructive surgery. In this study, we used a rat mandible model to assess the bone regeneration ability of u-HA/PLLA/PGA material, compared with uncalcined/unsintered hydroxyapatite and poly-l-lactide acid (u-HA/PLLA) material, which has demonstrated excellent bone regenerative ability. A 4-mm-diameter defect was created at the mandibular angle area in 28 Sprague Dawley male rats. The rats were divided into three groups: u-HA/PLLA/PGA (u-HA/PLLA/PGA graft + defect), u-HA/PLLA (u-HA/PLLA graft + defect), and sham control (defect alone). At 1, 3, 8, and 16 weeks after surgeries, the rats were sacrificed and assessed by micro-computed tomography, histological analysis with hematoxylin and eosin staining, and immunohistochemical analyses. The results confirmed that the accelerated bone bioactive/regenerative osteoconduction of u-HA/PLLA/PGA was comparable with that of u-HA/PLLA in the rat mandible model. Furthermore, this new regenerative nanomaterial was able to more rapidly induce bone formation in the early stage and had great potential for further clinical applications in maxillofacial reconstructive surgery.

scholarly journals Combined secondary compounds naturally found in nectars enhance honeybee cognition and survival

2021 ◽  
Vol 224 (6) ◽  
Author(s):  
Ignacio L. Marchi ◽  
Florencia Palottini ◽  
Walter M. Farina
Keyword(s):  
Cognitive Ability ◽  
Sucrose Solution ◽  
Synergistic Effects ◽  
Secondary Compounds ◽  
Learning Performance ◽  
Memory Retention ◽  
Olfactory Conditioning ◽  
Significant Survival ◽  
Short And Long Term

ABSTRACT The alkaloid caffeine and the amino acid arginine are present as secondary compounds in nectars of some flower species visited by pollinators. Each of these compounds affects honeybee appetitive behaviours by improving foraging activity and learning. While caffeine potentiates responses of mushroom body neurons involved in honeybee learning processes, arginine acts as precursor of nitric oxide, enhancing the protein synthesis involved in memory formation. Despite existing evidence on how these compounds affect honeybee cognitive ability individually, their combined effect on this is still unknown. We evaluated acquisition and memory retention in a classical olfactory conditioning procedure, in which the reward (sucrose solution) contained traces of caffeine, arginine or a mixture of the two. The results indicate that the presence of the single compounds and their most concentrated mixture increases bees' learning performance. However, memory retention, measured in the short and long term, increases significantly only in those treatments offering combinations of the two compounds in the reward. Additionally, the most concentrated mixture triggers a significant survival rate in the conditioned bees. Thus, some nectar compounds, when combined, show synergistic effects on cognitive ability and survival in an insect.

scholarly journals Exposure to the RXR agonist SR11237 in early life causes disturbed skeletal morphogenesis in a rat model

2019 ◽  
Author(s):  
Holly Dupuis ◽  
Michael Andrew Pest ◽  
Ermina Hadzic ◽  
Thin Xuan Vo ◽  
Daniel B. Hardy ◽  
...  
Keyword(s):  
Growth Plate ◽  
Bone Growth ◽  
Long Bone ◽  
Tunel Staining ◽  
Long Bones ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Calcified Tissue ◽  
Trap Staining ◽  
Tomography Scanning

AbstractLongitudinal bone growth occurs through endochondral ossification (EO), controlled by various signaling molecules. Retinoid X Receptor (RXR) is a nuclear receptor with important roles in cell death, development, and metabolism. However, little is known about its role in EO. In this study, the agonist SR11237 was used to evaluate RXR activation on EO.Rats given SR11237 from post-natal day 5 to 15 were harvested for micro-computed tomography scanning and histology. In parallel, newborn CD1 mouse tibiae were cultured with increasing concentrations of SR11237 for histological and whole mount evaluation.RXR agonist-treated rats were smaller than controls, and developed dysmorphia of the growth plate. Cells invading the calcified and dysmorphic growth plate appeared pre-hypertrophic in size and shape corresponding with P57 immunostaining. Additionally, SOX9 positive cells were found surrounding the calcified tissue. The epiphysis of SR11237 treated bones showed increased TRAP staining, and additional TUNEL staining at the osteo-chondral junction. MicroCT revealed morphological disorganization in the long bones of treated animals. Isolated mouse long bones treated with SR11237 grew significantly less than their DMSO controls.This study demonstrates that stimulation of the RXR receptor causes irregular ossification, premature closure of the growth plate, and disrupted long bone growth in rodent models.

Amentoflavone Inhibits Osteoclastogenesis and Wear Debris-Induced Osteolysis via Suppressing NF-κB and MAPKs Signaling Pathways

Planta Medica ◽  
2018 ◽  
Vol 84 (11) ◽  
pp. 759-767 ◽  
Author(s):  
Zhen Zhang ◽  
Shuai Zhao ◽  
Xiaolei Li ◽  
Xiaoqi Zhuo ◽  
Wu Zhang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Aseptic Loosening ◽  
Wear Debris ◽  
Mitogen Activated Protein Kinase ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Mitogen Activated Protein ◽  
And Function

AbstractWear debris-induced osteolysis is one of the major reasons for subsequent aseptic loosening after cementless hip arthroplasty. Increasing evidence suggests that receptor activator of nuclear factor kappa-B (NF-κB) ligand-mediated osteoclastogenesis and osteolysis are responsible for wear debris-induced aseptic loosening. In the present study, we explored the effect of amentoflavone (AMF) on inhibiting osteoclast generation and wear debris-induced osteolysis in vitro and in vivo. Twenty-four male C57BL/J6 mice were randomly divided into four groups: a sham group and groups with titanium wear debris treatment followed by intraperitoneal injection of various concentrations of AMF (0, 20, and 40 mg/kg/day). The micro computed tomography scanning and histological analysis were performed. Bone marrow-derived macrophages were cultured to investigate the effect of AMF on osteoclast generation and function. The results showed that AMF suppressed osteoclastogenesis, F-actin ring formation, and bone absorption without cytotoxicity. AMF prevented titanium wear debris-induced osteolysis in mice. AMF suppressed the relative proteins of NF-κB and mitogen-activated protein kinase (MAPKs) signaling pathways. Thus, the present study suggests that AMF derived from plants could inhibit osteoclastogenesis and titanium wear debris-induced osteolysis via suppressing NF-κB and MAPKs signaling pathways.

Multiscale imaging of the rat brain using an integrated diceCT and histology workflow

2021 ◽  
Author(s):  
Paul M. Gignac ◽  
Haley D. O’Brien ◽  
Jimena Sanchez ◽  
Dolores Vazquez Sanroman
Keyword(s):  
Computed Tomography ◽  
Low Cost ◽  
Three Dimensional ◽  
Adolescent Male ◽  
Cresyl Violet ◽  
Sprague Dawley ◽  
Biomedical Sciences ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Neural Tissues

Abstract Advancements in tissue visualization techniques have spurred significant gains in the biomedical sciences by enabling researchers to integrate their datasets across anatomical scales. Of particular import are techniques that enable the interpolation of multiple hierarchical scales in samples taken from the same individuals. This study demonstrates that two-dimensional histology techniques can be employed on neural tissues following three-dimensional diffusible iodine-based contrast-enhanced computed tomography (diceCT) without causing tissue degradation. This represents the first step toward a multiscale pipeline for brain visualization. We studied brains from adolescent male Sprague-Dawley rats, comparing experimental (diceCT-stained then de-stained) to control (without diceCT) brains to evaluate neural tissues for immunolabeling integrity, compare somata sizes, and distinguish neurons from glial cells within the telencephalon and diencephalon. We hypothesized that if experimental and control samples do not differ significantly in quantitative metrics, brain tissues are robust to the chemical, temperature, and radiation environments required for these multiple, successive imaging protocols. Visualizations for experimental brains were first captured via micro-computed tomography scanning of isolated, iodine-infused specimens. Samples were then cleared of iodine, serially sectioned, and prepared again using immunofluorescent, fluorescent, and cresyl violet labeling, followed by imaging with confocal and light microscopy, respectively. Our results show that many neural targets are resilient to diceCT imaging and compatible with downstream histological staining as part of a low-cost, multiscale brain imaging pipeline.

Ontogenetic development of the otic region in the new model organism, Leucoraja erinacea (Chondrichthyes; Rajidae)

2018 ◽  
Vol 109 (1-2) ◽  
pp. 105-114 ◽  
Author(s):  
Cathrin PFAFF ◽  
Jürgen KRIWET ◽  
Kyle MARTIN ◽  
Zerina JOHANSON
Keyword(s):  
Soft Tissues ◽  
Developmental Stages ◽  
Model Organism ◽  
Model Organisms ◽  
Biological Research ◽  
Developmental Studies ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Cartilaginous Fishes ◽  
Tomography Scanning

ABSTRACTCartilaginous fishes have a long evolutionary history dating back 440 million years and include model organisms in a number of fields of biological research. However, comparative developmental studies of these organisms, particularly neuroanatomical investigations, still remain sparse. Here, pre-hatching to adult developmental stages of the Little Skate, Leucoraja erinacea, are investigated using micro-computed tomography scanning in conjunction with staining procedures designed to improve visualisation of soft tissues. Within the ear, the anatomy of the skeletal labyrinth changes during ontogeny and differs substantially from the underlying membranous system, contrary to previous observations in sharks. Additionally, substantial morphological remodelling characterises the parietal fossa, which appears initially as a massive and hook-like structure and subsequently becomes slender and surrounded by soft tissue. The sizes of the vestibular system and neurocranium increase isometrically from pre- to post-hatching phases, and then exponentially after the post-hatching stages.

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