Masting promotes transformation from predation to mutualism in an oak-weevil-rodent system.

The significance of ecological non-monotonicity (a function whose first derivative changes signs) in shaping the structure and functions of the ecosystem has recently been recognized, but such studies involving high-order interactions are rare. Here, we have proposed a three-trophic conceptual diagram on interactions among trees, rodents, and insects in mast and non-mast years and tested the hypothesis that oak (Quercus wutaishanica) masting could result in increased mutualism and less predation in an oak-weevil-rodent system in a warm temperate forest of China. Our 14-year dataset revealed that mast years coincided with a relatively low rodent abundance but a high weevil abundance. Masting not only benefited seedling recruitment of oaks through increased dispersal by rodents but also a decrease in predation by rodents and weevils, as well as an increase in the overwintering survival of rodents. Masting appeared to have increased weevil survival by reducing predation of infested acorns by rodents. These results suggest that masting benefits all participants in the plant-insect-rodent system by increasing mutualism and reducing predation behavior (i.e., a non-monotonic function). Our study highlights the significance of masting in maintaining the diversity and function of the forest ecosystem by facilitating the transformation from predation to mutualism among trophic species.

Dibutyl phthalate adsorbed on multi-walled carbon nanotubes can aggravate liver injury in mice via the Jak2/STAT3 pathway.

Phthalic acid esters (PAEs) and carbon nanotubes (CNTs) are common environmental pollutants and may degrade differently with different resulting biotoxicity, when present together. This study investigated the toxicological effects of singular or combined exposure to dibutyl phthalate (DBP) and multi-walled carbon nanotubes (MWCNTs) in KM mice. Results indicated that combined exposure led to slower weight gain and an increased leukocyte count in the blood, as well as liver tissue lesions and downregulation of organ coefficients. Additionally, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were elevated in the liver, and glucose, pyruvate, triglyceride (TG), and total cholesterol (T-CHO) were significantly reduced, suggesting compromised liver function. Furthermore, mRNA levels of genes related to hepatic glucose and lipid metabolism were significantly altered. These findings suggest that combined exposure to DBP and MWCNTs can have severe impacts on liver function in mice, highlighting the importance of considering interactions between multiple contaminants in environmental risk assessments.

Combined exposure to multiwalled carbon nanotubes and dibutyl phthalates aggravated airway inflammation in rats.

Previous work has shown that mice exposed to dibutyl phthalate (DBP) adsorbed onto multi-walled carbon nanotubes (MWCNTs), via tail vein injection, displayed black lesions in their lungs. To investigate the mechanism causing this toxicity in the lung tissue, we performed an experiment with rats, exposing them to DBP adsorbed onto MWCNTs via a tail vein injection for 14 days. The results revealed pulmonary edema and greyish-black lung tissue in the MWCNTs and the MWCNTs + DBP combined exposure groups. In the combined exposure group there was evident alveolar fragmentation and adhesion, and lung tissue sections showed significant levels of black particles. Sections of the non-cartilaginous region of the trachea had significant folding of the pseudostratified ciliated columnar epithelium and marked thickening of the submucosa. In broncho alveolar lavage fluid, the number of leukocytes (WBC), lymphocytes (Lym), neutrophils (Neu), and eosinophils (Eos), as well as levels of immunoglobulin E (IgE), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin 1ß (IL-1ß) were all significantly higher. TNF-α, IL-6, signal transducer and activator of transcription 3 (STAT3), and α-smooth muscle actin (α-SMA) mRNA expression were all elevated in the lung tissue. The combined exposure group, which had considerable airway remodeling, had a greater degree of tracheal constriction and luminal narrowing, according to the results of the α-SMA immunofluorescence assay. According to these experimental findings, the exposure to both MWCNTs and DBP seemed to have a synergistic effect and exacerbated rats' impaired respiratory function that resulted from exposure to MWCNTs alone.

Dibutyl Phthalate Adsorbed on Multiwalled Carbon Nanotubes Causes Fetal Developmental Toxicity in Balb/C Mice.

This study investigated whether using multiwalled carbon nanotubes (MWCNTs) as a carrier for dibutyl phthalate (DBP) could delay the degradation rate of DBP in mice and increase its estrogen-like interference effect. Pregnant Balb/C mice were divided into four groups and exposed to different treatments via tail-vein injection every 3 days until gestational day 20. The female and male mice were then sacrificed for toxicological study. The results showed that the combination of MWCNTs and DBP resulted in a higher fetal mortality rate than if the mice were exposed to MWCNTs or DBP alone. H&E staining showed that the estrous period of the exposed mice was delayed, the development of oocytes was blocked in the combination group, the number of spermatogenic cells decreased, and the quality of sperm decreased. Our experiment showed that the expression levels of the genes involved in sex hormone synthesis in the testis and ovaries were significantly increased after combined treatment compared with the MWCNT group (p < 0.01). The study suggests that DBP degradation is delayed when absorbed on MWCNTs, which increases its estrogen-like interference and interferes with fetal development, ultimately leading to increased fetal mortality.

Asymmetric competition for seeds between two sympatric food hoarding rodents: implications for coexistence.

Asymmetric competition occurs when some species have distinct advantages over their competitors and is common in animals with overlapping habitats and diet. However, the mechanism allowing coexistence between asymmetric competitors is not fully clear. Chinese white-bellied rats (Niviventer confucianus, CWR) and Korean field mice (Apodemus peninsulae, KFM) are common asymmetric competitors in shrublands and forests west of Beijing city. They share similar diet (e.g. plant seeds) and activity (nocturnal), but differ in body size (CWR are bigger than KFM), food hoarding habit (CWR: mainly larder hoarding; KFM: both larder and scatter hoarding), and ability to protect cached food (CWR are more aggressive than KFM). Here, we tested seed competition in 15 CWR-KFM pairs over a 10-day period under semi-natural enclosure conditions to uncover the differences in food hoarding, cache pilferage, and food protection between the 2 rodents, and discuss the implication for coexistence. Prior to pilferage, CWR harvested and ate more seeds than KFM. CWR tended to larder hoard seeds, whereas KFM preferred to scatter hoard seeds. Following pilferage, CWR increased consumption, decreased intensity of hoarding, and pilfered more caches from KFM than they lost, while KFM increased consumption more than they hoarded, and they preferred to hoard seeds in low and medium competition areas. Accordingly, both of the 2 rodent species increased their total energy consumption and hoarding following pilferage. Both rodent species tended to harvest seeds from the source, rather than pilfer caches from each other to compensate for cache loss via pilferage. Compared to CWR, KFM consumed fewer seeds when considering seed number, but hoarded more seeds when considering the seeds' relative energy (energy of hoarded seeds/rodent body mass2/3 ) at the end of the trials. These results suggest that asymmetric competition for food exists between CWR and KFM, but differentiation in hoarding behavior could help the subordinate species (i.e. KFM) hoard more energy than the dominant species (i.e. CWR), and may contribute to their coexistence in the field.

A global evaluation of the associations between long-term dynamics of seed falls and rodents.

One classic system of pulsed resource and animal population is mast seeding and population dynamics of seed-eating rodents in forests. However, we still lack an understanding of the global patterns regarding the contributions of seed falls to rodent outbreaks or population dynamics. We analyzed a global dataset of coupled long-term time series of seed abundances and rodent populations from published literature, including 66 and 89 time series (156 rodent-seed pairs from 37 studies) for rodent and seed abundances, respectively. We found only half of the examined rodent populations showed statistically significant coincidence between rodent outbreak and mast-seeding years. Over all the coupled time series, seed abundance was found to positively correlate with rodent abundance with a one-year lag, and the relative importance of seed abundance was much lower than that of density dependence in affecting rodent population growth rates. We also found the relative importance of seed abundance decreased, but that of rodent density dependence increased with the latitude of study. For the first time, our work provides a global pattern on the associations between seed falls and rodent population dynamics mostly in mid- and high-latitude forests, and highlights the necessity of more long-term studies on this subject in more forest ecosystems.

Whole-genome sequencing reveals the genetic mechanisms of domestication in classical inbred mice.

BACKGROUND: The laboratory mouse was domesticated from the wild house mouse. Understanding the genetics underlying domestication in laboratory mice, especially in the widely used classical inbred mice, is vital for studies using mouse models. However, the genetic mechanism of laboratory mouse domestication remains unknown due to lack of adequate genomic sequences of wild mice. RESULTS: We analyze the genetic relationships by whole-genome resequencing of 36 wild mice and 36 inbred strains. All classical inbred mice cluster together distinctly from wild and wild-derived inbred mice. Using nucleotide diversity analysis, Fst, and XP-CLR, we identify 339 positively selected genes that are closely associated with nervous system function. Approximately one third of these positively selected genes are highly expressed in brain tissues, and genetic mouse models of 125 genes in the positively selected genes exhibit abnormal behavioral or nervous system phenotypes. These positively selected genes show a higher ratio of differential expression between wild and classical inbred mice compared with all genes, especially in the hippocampus and frontal lobe. Using a mutant mouse model, we find that the SNP rs27900929 (T>C) in gene Astn2 significantly reduces the tameness of mice and modifies the ratio of the two Astn2 (a/b) isoforms. CONCLUSION: Our study indicates that classical inbred mice experienced high selection pressure during domestication under laboratory conditions. The analysis shows the positively selected genes are closely associated with behavior and the nervous system in mice. Tameness may be related to the Astn2 mutation and regulated by the ratio of the two Astn2 (a/b) isoforms.

Exposure to dibutyl phthalate adsorbed to multi-walled carbon nanotubes causes neurotoxicity in mice by inducing the release of BDNF.

Multi-walled carbon nanotubes (MWCNTs) and dibutyl phthalate (DBP) exist extensively in the environment, and they are easy to form compound pollution through π-π interactions in the environment. We investigate whether DBP, an environmental hormone disruptor, mediated by CNTs can more easily cross the blood-brain barrier, and whether DBP entering the brain has neurotoxic effects on the cells in the brain. Experimental subjects were 40 male Kunming (KM) mice randomly divided into 4 groups: the control group; the MWCNTs group; the DBP group; and the MWCNTs+DBP group. The mice were exposed via tail intravenous injection once every 3 days for 21 days, following which toxicology studies were carried out. The results of behavioral experiments showed that the mice in the combined exposure group (MWCNTs+DBP) exhibited spatial learning and memory impairment, and anxiety-like behavior. Staining of hippocampal sections of mouse brain tissue showed that, in the CA1, CA2, and DG areas, the number of neurons decreased, the nucleus was pyknotic, the cell body was atrophied, and levels of the microglia marker Iba-1 increased. By proteomic KEGG analysis, we found that the DEPs were mainly those related to neurodegenerative diseases. Immunohistochemistry in the hippocampus indicated that the level of brain-derived neurotrophic factor (BDNF) in the DG region was significantly increased. RT-PCR results revealed that the expression levels of P53, caspase3, and Bax genes related to apoptosis were up-regulated. The experimental results demonstrated that the mechanism of the combined-exposure injury to neurons in the hippocampus of mice may be that MWCNTs with adsorbed DBP can induce the release of BDNF, accelerate the apoptosis of neurons, and reduce the number of nerve cells, which activates microglia, causing neuroinflammation and nervous system toxicity.

Reproductive toxicity of dibutyl phthalate adsorbed on carbon nanotubes in male Balb/C mice.

Dibutyl phthalate (DBP) is an environmental hormone disrupter. This study was designed to investigate whether DBP adsorbed in multi-walled carbon nanotubes (MWCNTs) can easily cross the blood-testis barrier and slow down the degradation of DBP in male mice, thereby prolonging the interference effect of DBP. The results showed that: in male Balb/C mice, the sperm density of the MWCNTs group and the DBP plus MWCNTs group decreased significantly (p < 0.05); and the sperm deformity rate increased significantly (p < 0.05). Testicular tissue sections from the combined exposure group showed that most of the seminiferous tubules were atrophied, there were more large gaps between the cells in the tubules, and the number of mature-sperm decreased. The reactive oxygen species (ROS) levels increased significantly in the combined exposure group (p < 0.01). Proteomics results showed that there were 231 differentially expressed proteins in the combined exposure group compared with the MWCNTs only group, and 69 differentially expressed proteins compared with the DBP group. GO enrichment analysis showed that the differentially expressed proteins mainly include: 60 s acid ribosomal protein P1; nuclear autoantigen sperm protein; centromere protein V; and other proteins related to cell division. These results indicate that MWCNTs with adsorbed DBP can increase oxidative damage in the testis of male mice, interfere with DNA replication and cell division in testicular tissue cells, induce cell apoptosis, and destroy the normal spermatogenic function of the testis.

Exposure to a combination of MWCNTs and DBP causes splenic toxicity in mice.

The large conjugated π bond in the molecular structure of carbon nanotubes (CNTs) interacts with the benzene ring structure in di (n-butyl) phthalates (DBP) through a π - π bond. Compounds of CNTs and DBP form easily, becoming another environmental pollutant of concern. We explore whether CNTs entering animals slow down the degradation of the DBP adsorbed in the CNT cavity, thereby prolonging the "hormonal activity" of DBP. In our study, male BALb/c mice were used as experimental subjects divided into four groups: the control group; the multi-walled carbon nanotubes (MWCNTs) exposure group (10mg/kg/d); the DBP exposure group (2.15 mg/kg/d); and the compound exposure group (MWCNTs + DBP). After 30 days of exposure, the mice were sacrificed and their spleens used for immunotoxicology study. The results showed that the exposure groups exhibited splenomegaly and suffered severe oxidative damage to the spleen. In the compound exposure group: levels of IgA and IgG in the serum of the mice changed, and were significantly different from levels in both the MWCNTs and DBP exposure groups (p <0.05); the pathological sections of the spleen showed that the boundary between the white pulp area (WP) and the red pulp area (RP) was blurred, that the cell arrangement was loose, and that more red blood cells were retained in the spleen. Proteomics mass spectrometry analysis showed that compared with the control group, 70 proteins were up-regulated and 27 proteins were down-regulated in the MWCNTs group, 36 proteins were up-regulated and 23 proteins were down-regulated in the DBP group, 87 proteins were up-regulated and 21 proteins were down-regulated in the compound exposure group. The results of GO enrichment analysis and KEGG enrichment analysis of the differentially expressed proteins showed that the compound exposure harmed the spleen antigen recognition, processing, and presentation, inhibited the activation and proliferation of B cells and T cells, and hindered the adaptive immune responses. Our results showed that MWCNTs and DBP compounds can damage the spleen, and impair the innate and adaptive immune functions of the body.

Assessment of habitat change on bird diversity and bird-habitat network of a Coral Island, South China Sea.

BACKGROUND: Understanding how island ecosystems change across habitats is a major challenge in ecological conservation under the conditions of habitat degradation. According to a 2-year investigation on Dong Island of the Paracel Islands, South China Sea, we assessed the roles of different habitats at the species level and community level of birds using topological and network analysis. RESULTS: In addition to the thousands of Sula sula (a large-sized arboreal seabird) inhabiting the forests, there were 56 other bird species were recorded, representing 23 families and 12 orders, ranging in habitats of wetlands, forests, shrublands, grasslands, and/or beaches. The bird-habitat network had high nestedness, and bird species showed obvious clustering distribution. Integrated topological and network analysis showed that wetlands had a high contribution to species diversity and network structure, and it was a cluster center of migrant birds. Forests and grasslands were species hub and connector respectively, and forests were also the key habitat for residents. Beaches and shrublands were peripherals. The loss of wetlands and forests will result in a sharp reduction of species richness, and even make the S. sula, and most of the resident birds, become locally extinct. CONCLUSIONS: These results suggest that the wetland and forest habitats on the focal island are key important for migrant birds and resident birds respectively, and therefore much more attention should be paid to conservation of the focal island ecosystems.

Does public fear that bats spread COVID-19 jeopardize bat conservation?

With >1 400 species, bats comprise the second-largest order of mammals and provide critical ecological services as insect consumers, pollinators, and seed dispersers. Yet, bats are frequently associated with infectious human diseases such as SARS, MERS, and Ebola. As early as the end of January 2020, several virological studies have suggested bats as a probable origin for SARS-CoV-2, the causative agent of COVID-19. How does the public view the role of bats in COVID-19? Here we report pilot data collected shortly after the outbreak of COVID-19 using two online surveys, combined with a conservation intervention experiment, primarily on people who are receiving or have received higher education in China. We found that 84% of the participants of an online survey (n = 13 589) have misunderstood the relationship between bats and COVID-19, which strengthened negative attitudes towards bats. Knowledge of bats, gender, and education level of the participants affected their attitudes towards bats. Participants who indicated a better knowledge of bats had a more positive attitude towards bats. The proportion of female participants who had negative attitudes towards bats was higher than that of male participants. Participants with a higher education level indicated a more positive attitude towards bats after the outbreak of COVID-19. A specially prepared bat conservation lecture improved peoples' knowledge of bats and the positive attitudes, but failed to correct the misconception that bats transmit SARS-CoV-2 to humans directly. We suggest that the way virologists frame the association of bats with diseases, the countless frequently inaccurate media coverages, and the natural perceptual bias of bats carrying and transmitting diseases to humans contributed to the misunderstandings. This probably led to a rise in the events of evicting bats from dwellings and structures by humans and the legislative proposal for culling disease-relevant wildlife in China. A better understanding of the relationship between disease, wildlife and human health could help guide the public and policymakers in an improved program for bat conservation.

Mutualism between antagonists: its ecological and evolutionary implications.

Mutualism or antagonism between species is often investigated within the framework of monotonic interactions of either mutualism or antagonism, but studies on transition from mutualism to antagonism (within the context of nonmonotonic interactions) have been largely ignored. In this paper, through a brief review and synthesis, we highlighted the role of mutualism between antagonists in regulating the ecological and evolutionary processes, as well as maintaining the stability and complexity of ecosystems. Mutualism between antagonistic species represents the density-dependent transition between mutualism and antagonism, which is beneficial to species coexistence and stability of complex ecosystems; thus, it should be favored by natural selection. Species may face selection of conflicting pressure on functional traits in co-balancing mutualism and antagonism, which may result in evolution of the dual character of species with moderate mutualistic or antagonistic traits. Coevolution and co-balance of these traits are driving forces in shaping mutualism-antagonism systems. Rewards for mutualists, punishment for exploiters, and competition of meta-communities are essential in stabilizing mutualism between antagonists. We appeal for more studies on mutualism between antagonists and its ecological and evolutionary implications by expanding the conventional ecological studies from monotonic to nonmonotonic regimes.

Effects of masting on seedling establishment of a rodent-dispersed tree species in a warm-temperate region, northern China.

Masting is an evolutionary strategy used by plants to promote seed survival and/or seed dispersal under animal predation, but its effects on seedling establishment in field condition are rarely tested by long-term experiments incorporating combined effects of seed and animal abundance. Here, we tracked seed production, rodent-mediated seed dispersal, and seedling establishment in Armeniaca sibirica from 2005 to 2014 in a warm-temperate forest in northern China, and examined the effects of seed abundance and per capita seed availability on seed fate and seedling recruitment rate. Our results showed that seed abundance or per capita seed availability generally benefited the seedling recruitment of A. sibirica through increasing dispersal intensity, supporting predator dispersal hypothesis. However, seedling recruitment showed satiated or even dome-shaped association with per capita seed availability, suggesting the benefit to trees would be decreased when seed abundance were too high as compared to rodent abundance (a satiated effect). Our results suggest that the predator dispersal and satiation effects of masting on seedling recruitment can operate together in one system and conditionally change with seed and animal abundance.

Learning and memory impairment of mice caused by gaseous formaldehyde.

In order to study the e of formaldehyde exposure on learning and memory ability of mice. We used Kun Ming (KM) mice to demonstrate the neurotoxic effects of FA, and Balb/c mice to explore the neurobiological mechanism. The Morris water maze (MWM) test showed that the exposure of gaseous formaldehyde could cause spatial learning and memory impairment in mice. H & E staining showed that in the 3.0 mg/m3 formaldehyde exposed group, the arrangement of pyramidal cells in CA1 area of mouse hippocampus was loose and disordered, the cell morphology was swollen and deformed, and the apical dendrites were shortened or even disappeared. Biochemical indicators revealed high doses of FA exposure could cause oxidative damage in brain. Compared with the control group, there were significant differences in the levels of ROS, MDA, GSH and 8-OHDG in the 3.0 mg/m3 group (P < 0.01), also the monoamine neurotransmitters content and the content of TNF-α, IL-1ß and Caspase-3 (P < 0.01). Furthermore, the concentrations of cAMP, cGMP, NO and the activity of NOS in the cerebral cortex, hippocampus and brain stem after high doses of FA exposure were significantly different from those in the control group, indicating that FA exposure could interfere with the transduction of NO/cGMP signaling pathway. The results showed that FA could induce cognitive deficits and this extended investigation found that the toxicity of FA to the mouse nervous system is related to the NO/cGMP and cAMP signaling pathways.

Context-dependent responses of food-hoarding to competitors in Apodemus peninsulae: implications for coexistence among asymmetrical species.

Superior species may have distinct advantages over subordinates within asymmetrical interactions among sympatric animals. However, exactly how the subordinate species coexists with superior species is unknown. In the forests west of Beijing City, intense asymmetrical interactions of food competition exist among granivorous rodents (e.g. Apodemus peninsulae, Niviventer confucianus, Sciurotamias davidianus and Tscherskia triton) that have broadly overlapping habitats and diets but have varied body size (range 15-300 g), hoarding habits (scatter vs larder) and/or daily rhythm (diurnal vs nocturnal). The smallest rodent, A. peninsulae, which typically faces high competitive pressure from larger rodents, is an ideal model to explore how subordinate species coexist with superior species. Under semi-natural enclosure conditions, we tested responses of seed-hoarding behavior in A. peninsulae to intraspecific and interspecific competitors in the situations of pre-competition (without competitor), competition (with competitor) and post-competition (competitor removed). The results showed that for A. peninsulae, the intensity of larder-hoarding increased and the intensity of scatter-hoarding declined in the presence of intraspecifics and S. davidianus, whereas A. peninsulae ceased foraging and hoarding in the presence of N. confucianus and T. triton. A. peninsulae reduced intensity of hoarding outside the nest and moved more seeds into the nest for larder-hoarding under competition from intraspecific individuals and S. davidianus. In most cases, the experimental animals could recover to their original state of pre-competition when competitors were removed. These results suggest that subordinate species contextually regulate their food-hoarding strategies according to different competitors, promoting species coexistence among sympatric animals that have asymmetrical food competition.

Low concentrations of FA exhibits the Hormesis effect by affecting cell division and the Warburg effect.

Formaldehyde (FA), a ubiquitous indoor environmental pollutant, has been classified as a carcinogen. There are many studies showed that low levels of FA could promote cell proliferation, however, little is known about the signal pathways. To determine the potential molecular mechanisms, human chronic myeloid leukemia cells (K562 cells) and human bronchial epithelial cells (16HBE cells) were exposed to different concentrations of FA. The data showed that FA at 0-125 µM or 0-60 µM promoted the proliferation of K562 cells or 16HBE cells respectively, indicating that FA did have the Hormesis effect. FA at 75 µM (K562 cells) and 40 µM (16HBE cells) significantly promoted cell proliferation, increased intracellular reactive oxygen species (ROS) levels, and decreased glutathione (GSH) content. At the same time, FA treatment induced a marked increase in the key molecules of cell division like CyclinD-cdk4 and E2F1. In addition, pyruvate kinase isozyme M2 (PKM2), glucose, glucose transporter 1 (GLUT1), lactic acid and lactate dehydrogenase A (LDHA) content in the Warburg effect were increased. Administering Vitamin E (VE), significantly disrupted cell division and disturbed the Warburg effect, effectively indicating the decrease of cell activity. Conclusively, these findings suggested that low concentrations of FA could promote cell proliferation by accelerating cell division process or enhancing the Warburg effect to embody the Hormesis effect.

Visual and auditory cues facilitate cache pilferage of Siberian chipmunks (Tamias sibiricus) under indoor conditions.

In the struggle for survival, scatter-hoarding rodents are known to cache food and pilfer the caches of others. The extent to which rodents utilize auditory/visual cues from conspecifics to improve cache-pilfering is unknown. Here, Siberian chipmunks (Tamias sibiricus) were allowed to search for caches of Corylus heterophylla seeds (man-made caches and animal-made caches) after experiencing cues from a conspecific's cache-searching events. For each type of cache, 3 experimental scenarios were presented: (1) alone (control); (2) auditory/visual (hearing and seeing conspecific's cache-searching events); and (3) auditory only (hearing conspecific's cache-searching events only) with random orders. The subjects located man-made caches faster, harvested more caches, and hoarded more seeds both in the auditory/visual and the auditory only treatments compared to the control, while scatter-hoarding more seeds in the auditory/visual treatment but larder-hoarding more seeds in the auditory only treatment. Compared to the control, the animals spent less time locating animal-made caches, harvested more caches, ate fewer seeds, larder-hoarded more seeds and hoarded more seeds in total both in the auditory/visual and the auditory only treatments, while eating more seeds and hoarded fewer seeds in total in the auditory only treatment than in the auditory/visual treatment. The results also show that females spent less time locating the animal-made caches, but they scatter-hoarded fewer seeds than males in the auditory/visual treatment. To the best of our knowledge, this is the first report that visual and/or auditory cues of conspecifics improve cache-pilfering and hoarding in rodents.

UCH-L1 Inhibition Suppresses tau Aggresome Formation during Proteasomal Impairment.

In conditions of proteasomal impairment, the damaged or misfolded proteins, collectively known as aggresome, can accumulate in the perinuclear space and be subsequently eliminated by autophagy. Abnormal aggregation of microtubule-associated protein tau in the cytoplasm is a common neuropathological feature of tauopathies. The deficiency in ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), a proteasomal deubiquitinating enzyme, is closely related to tau aggregation; however, the associated mechanisms remain unclear. Here, we showed that UCH-L1 inhibition interrupts proteasomal impairment-induced tau aggresome formation. By reducing the production of lysine (K63)-linked ubiquitin chains, UCH-L1 inhibition decreases HDAC6 deacetylase activity and attenuates the interaction of HDAC6 and tau protein, finally leading to tau aggresome formation impairment. All these results indicated that UCH-L1 plays a key role in the process of tau aggresome formation by regulating HDAC6 deacetylase activity and implied that UCH-L1 may act as a signaling molecule to coordinate the effects of the ubiquitin-proteasome system and the autophagy-lysosome pathway, which mediate protein aggregates degradation in the cytoplasm.