Enterococcus faecalis provides protection during scavenging in carrion crow (Corvus corone)

The gut microbiota significantly influences host physiology and provides essential ecosystem services.While diet can affect the composition of the gut microbiota,the gut microbiota can also help the host adapt to specific dietary habits.The carrion crow(Corvus corone),an urban facultative scavenger bird,hosts an abundance of pathogens due to its scavenging behavior.Despite this,carrion crows infrequently exhibit illness,a phenomenon related to their unique physiological adaptability.At present,however,the role of the gut microbiota remains incompletely understood.In this study,we performed a comparative analysis using 16S rRNA amplicon sequencing technology to assess colonic content in carrion crows and 16 other bird species with different diets in Beijing,China.Our findings revealed that the dominant gut microbiota in carrion crows was primarily composed of Proteobacteria(75.51%)and Firmicutes(22.37%).Significant differences were observed in the relative abundance of Enterococcus faecalis among groups,highlighting its potential as a biomarker of facultative scavenging behavior in carrion crows.Subsequently,E.faecalis isolated from carrion crows was transplanted into model mice to explore the protective effects of this bacterial community against Salmonella enterica infection.Results showed that E.faecalis down-regulated the expression of pro-inflammatory cytokines tumor necrosis factor alpha(TNF-α),interferon gamma(IFN-γ),and interleukin 6(IL-6),prevented S.enterica colonization,and regulated the composition of gut microbiota in mice,thereby modulating the host’s immune regulatory capacity.Therefore,E.faecalis exerts immunoregulatory and anti-pathogenic functions in carrion crows engaged in scavenging behavior,offering a representative case of how the gut microbiota contributes to the protection of hosts with specialized diets.

Influence of Fireworks Igniting in Spring Festival of 2014 on Heavy Metal Content of Beijing Dust

Under strong influence of human activity,dust on urban street accumulates a large number of heavy metals difficult to be decomposed. Under certain dynamic conditions, dust with heavy metals enter into the air by re-suspension ,which harms environmental system and human health. Before and after fireworks igniting during Spring Festival of 2014,111 dust samples were randomly collected in Beijing, Tianjin, Shangqiu of Henan Province, and Shaoxing of Zhejiang Province and then Pb, Cr, Zn, As, Cu and Ni content was nondestructively analyzed. The results showed that when compared with soil background value, dust collected in Beijing very strongly accumulated Zn and Cu ;strongly accumulated Pb, moderately accumulated Cr due to human activities, while weakly accumulated As and Ni implying a little effect of human activity. Influenced by industry and port, heavy metals content in dust from coastal cities including Pb from Shaoxing, Cr from Tianjin and Shaoxing, Zn from Tianjin and Ni from Shaoxing, were relatively higher than that from inland cities including Beijing and Shangqiu. Otherwise, the average content of Cu in dust from Beijing was higher than that from other cities, probably released from smelting, fireworks igniting, and burning or abrading from automobile＇s gasoline, engine, lubricating oil or gold-plated parts. Fireworks igniting could variably increase the content of most heavy metals in dust. Cu content increased by 192.57%, Pb and Zn did by 23.73% and 34.05% respectively; Cr and Ni raised unobviously by 4.48% and 2.41% respectively.

Seasonal Trends of Polycyclic Aromatic Hydrocarbons in Particulate Matter at an Urban Site in Beijing, China

This study was conducted to examine the impact of vehicular traffic emissions on the seasonal trends of polycyclic aromatic hydrocarbons (PAHs) concentration in particulate matter in Beijing. The PM10 and PM2.5 samples were collected at an urban site near the Third Ring Road in Beijing, China, from July 2009 to March 2010. Individual PAH concentrations at urban traffic site ranged from n.d. (below the detection limit, 0.2 ng/m3) to 558.49 ng/m3 of benzo(b)fluoranthene in PM10 samples and from n.d. to 177.93 ng/m3 also for benzo(b)fluoranthene in PM2.5 samples. Seasonal variations of PAHs compounds indicated that PAHs concentration in autumn and winter was higher than those in spring and summer. Results of PCA give four and five significant factors, which could explain 83.1% of the variation for PM2.5 and 85.3% of the variation for PM10, respectively.

Musk secretion in muskrats(Ondatra zibethicus L.):association with lipid and cholesterol metabolism-related pathways

Male muskrats(Ondatra zibethicus L.)secrete musk from their scent glands during musk secretion season.Musk plays an important role as a communication pheromone during the breeding season.In this study,gas chromatography–mass spectrometry(GC–MS)was used to analyze the main components of musk.The GC–MS results after methyl esterification showed that 71.55%of the musk is composed of fatty acids.The other components of muskrat musk include cholesterol(9.31%)and other organics.Transcriptome comparison between musk secretion and non-secretion seasons showed significant changes in the scent glands for 53 genes involved in fatty acid and cholesterol synthesis and metabolism regulatory pathways,which include fatty acid biosynthesis,elongation,and metabolism;steroid biosynthesis;steroid hormone biosynthesis pathways.A reverse transcription–polymerase chain reaction analysis confirmed these detected changes.Overall,our results indicated that lipid synthesis and metabolism play important roles in musk compound synthesis by providing energy for musk production,and the produced musk provides a mechanism for male muskrats to communicate with females during the breeding season.

Diet drives convergent evolution of gut microbiomes in bamboo-eating species

Gut microbiota plays a critical role in host physiology and health.The coevolution between the host and its gut microbes facilitates animal adaptation to its specific ecological niche.Multiple factors such as host diet and phylogeny modulate the structure and function of gut microbiota.However,the relative contribution of each factor in shaping the structure of gut microbiota remains unclear.The giant(Ailuropoda melanoleuca)and red(Ailurus styani)pandas belong to different families of order Carnivora.They have evolved as obligate bamboo-feeders and can be used as a model system for studying the gut microbiome convergent evolution.Here,we compare the structure and function of gut microbiota of the two pandas with their carnivorous relatives using 16S rRNA and metagenome sequencing.We found that both panda species share more similarities in their gut microbiota structure with each other than each species shares with its carnivorous relatives.This indicates that the specialized herbivorous diet rather than host phylogeny is the dominant driver of gut microbiome convergence within Arctoidea.Metagenomic analysis revealed that the symbiotic gut microbiota of both pandas possesses a high level of starch and sucrose metabolism and vitamin B12 biosynthesis.These findings suggest a diet-driven convergence of gut microbiomes and provide new insight into host-microbiota coevolution of these endangered species.