Although forest degradation caused by dwarf bamboo overabundance has a significant effect on the survival of wild giant pandas, the degradation process and its impact on soil C, N and P stocks remain unclear. By investigating the vegetation structure and physicochemical analysis of litter and soil, we explored the changes in soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP) and available phosphorus (AP) stocks and the driving forces at three degradation levels triggered by dwarf bamboo overabundance in an important giant panda habitat—the subalpine coniferous forest. Dwarf bamboo overabundance following forest logging prevented tree regeneration, resulting in simplified a vegetation structure; even after 23 years of natural recovery, the clear-cut forestlands remained in the shrub stage, and the tree density and basal area were only 1.6% and 38%, respectively, of those in primary subalpine coniferous forest. With increasing degradation intensity, the litter stock and litter quality showed a decreasing trend, as did the SOC, N and P stocks in the litter layer and topsoil. The vegetation structure and litter quality together explained more than 90% of the variance in the C, N and P stocks (SOC: 97.3%, TNsoil: 93.5%, ANsoil: 96.2%, TPsoil: 97.2% and APsoil: 97.0%), and litter quality had greater explanatory power than the vegetation structure. The SEM analysis results showed that the increase in dwarf bamboo density caused by the reduction in tree basal area affected the litter C/N and C/P ratios, and ultimately reduced the SOC, Nsoil and Psoil stocks. This study highlights that dwarf bamboo overabundance not only causes forest degradation but also reduces the carbon sequestration function of giant panda habitat, leading to the loss of soil N and P. We suggest that reducing bamboo abundance can promote the recovery of the soil carbon, nitrogen and phosphorus stocks in degraded giant panda habitats.

China announced the development of its first 5 national parks in 2021, the primary objective of which is to conserve the natural state and integrity of natural ecosystems. As such, ecosystem services and biodiversity levels are crucial assessment factors for the parks. For Giant Panda National Park (GPNP), we evaluated ecological sensitivity based on water and soil erosion and rocky desertification; ecosystem services based on headwater conservation, soil and water conservation, and biodiversity conservation; and presence of giant panda (Ailuropoda melanoleuca) and sympatric species (e.g., takin [Budorcas taxicolor], Asiatic black bear [Ursus thibetanus]) habitat suitability derived from niche modeling to identify the ecosystem status and assess ecological problems within the park. From our results, we proposed ecologically critical areas to target to meet the park's goals. The suitable habitat for pandas and sympatric species encompassed 62.98% of the park and occurred mainly in the Minshan Mountains. One quarter of the total area (25.67%) contained areas important for ecosystem services. Ecologically sensitive and extremely sensitive areas covered 88.78% of the park and were distributed mainly in Qionglaishan and Minshan Mountains. This coverage indicated that there was much habitat for pandas and sympatric species but that the ecosystems in GPNP are vulnerable. Therefore, ecologically critical areas encompassed all suitable habitats for all the species examined and areas important and extremely important to ecosystem service provision,ecologically sensitive and extremely sensitive areas, encompassed 15.17% of panda habitat, accounted for 16.37% of the GPNP area, and were distributed mainly in the Minshan Mountains. Our results indicated where conservation efforts should be focused in the park and that by identifying ecologically critical areas managers can provide targeted protection for wildlife habitat and ecosystems and effectively and efficiently protect the composite ecosystem. Additionally, our methods can be used to inform development of new national parks.

To achieve reproduction, male solitary mammals need to locate females using chemical communication with high levels of precision. In the case of giant pandas, the total estrus period of females was usually 15 days each year, however, successful mating activity is finished within 3 days from respective home range. The mating pattern of giant pandas, where multiple males compete for each female requires females employ efficient systems to communicate their estrus phases. To verifying whether the scent secretions of giant pandas changes by gender and estrus progression, the microbiota and compounds in 29 anogenital gland samples from 14 individuals during estrus were analyzed by 16S rRNA sequencing and GC-MS. We show that the microbiota communities covary by gender with 4 particular compounds of scent secretions. Among 597 genera, 34 were identified as biomarkers that could be used to distinguish between different estrus phases. By bacterial-compounds co-analysis, 3 fatty ester acids and squalene compounds covaried with the development of estrus in the bacterial communities of female giant pandas. This study helps clarify how a large, solitary mammal expresses accurate information to improve the likelihood of successful reproduction by changing the composition of microbiota and odor compounds of anogenital glands during estrus.

Tick infestations have been reported as one of the factors threatening the health of giant pandas, but studies of viral pathogens carried by ticks feeding on the blood of giant pandas are limited. To assess whether blood-sucking ticks of giant pandas can carry viral pathogens and if so, whether the viruses in ticks are associated with those previously detected in giant panda hosts, we determined the viromes of ticks detached from giant pandas in a field stocking area in Sichuan Province, southwest China. Using viral metagenomics we identified 32 viral species in ticks, half of which (including anellovirus [n = 9], circovirus [n = 3], and gemycircularvirus [n = 4]) showed homology to viruses carried by giant pandas and their associated host species (such as red pandas and mosquitoes) in the same living domain. Remarkably, several viruses in this study phylogenetically assigned as bunyavirus, hepe-like virus, and circovirus were detected with relatively high abundance, but whether these newly identified tick-associated viruses can replicate in ticks and then transmit to host animals during a blood meal will require further investigation. These findings further expand our understanding of the role of giant panda-infesting ticks in the local ecosystem, especially related to viral acquisition and transmission, and lay a foundation to assess the risk for giant panda exposure to tick-borne viruses. IMPORTANCE Ticks rank only second to mosquitoes as blood-feeding arthropods, capable of spreading pathogens (including viruses, bacteria, and parasites) to hosts during a blood meal. To better understand the relationship between viruses carried by ticks and viruses that have been reported in giant pandas, it is necessary to analyze the viromes of giant panda-parasitic blood-sucking ticks. This study collected 421 ticks on the body surface of giant pandas in Sichuan Province, China. We characterized the extensive genetic diversity of viruses harbored by these ticks and reported frequent communication of viruses between giant pandas and their ticks. While most of the virome discovered here are nonpathogenic viruses from giant pandas and potentially tick-specific viruses, we revealed some possible tick-borne viruses, represented by novel bunyaviruses. This research contributes to the literature because currently there are few studies on the virome of giant pandainfesting ticks.

Cross-species transmission events were commonplace, with numerous cases of host-switching during the viral evolutionary history, but relatively little evidence for onward transmission in different species living in the same ecosystem. For understanding the communications of viruses in giant pandas (Ailuropoda melanoleuca) and their associated organisms, based on a large size of samples (N = 2305) collected between 2015 and 2020 from giant panda (N = 776) and other four giant panda-associated organisms in the same ecosystem, red pandas (N = 700), stray cats (N = 32), wild rats (N = 42), and mosquitoes (N = 755), viromics was used for the virus identification and subsequent virus traceability. The results showed that a feline panleukopenia virus (FPV) was found in giant pandas with clinical signs of vomiting and mild diarrhea. Meanwhile, the same FPV strain was also prevalent in the healthy red panda (Ailurus fulgens) population. From the viromes of the five different organisms, 250 virus genomes were determined. Our data revealed that besides FPV, other putative pathogenic viruses, such as red panda amdoparvoviruses (RPAVs) and Getah viruses (GETVs) were responsible for previous disease or death of some red pandas. We also demonstrated that a number of viruses were involved in potential interspecies jumping events between giant pandas and their associated species. Collectively, our results shed light on the genetic diversity and relationship of diverse viral pathogens in 'Giant pandas-Associated animals-Arthropods' and report some cases of possible viral host-switching among these host species living in the same ecosystem.

Ticks rank second in the world as vectors of disease. Tick infestation is one of the factors threatening the health and survival of giant pandas. Here, we describe the mitogenomes of Ixodes acutitarsus and Ixodes ovatus parasitizing giant pandas, and perform comparative and phylogenetic genomic analyses on the newly sequenced and other available mitogenomes of hard ticks. All six newly determined mitogenomes contain a typical gene component and share an ancient Arthropoda gene arrangement pattern. Our study suggests that I. ovatus is a species complex with high genetic divergence, indicating that different clades of I. ovatus represent distinct species. Comparative mitogenomic analyses show that the average A + T content of Ixodidae mitogenomes is 78.08%, their GC-skews are strongly negative, while AT-skews fluctuate around 0. A large number of microsatellites are detected in Ixodidae mitogenomes, and the main microsatellite motifs are mononucleotide A and trinucleotide AAT. We summarize five gene arrangement types, and identify the trnY-COX1-trnS1-COX2-trnK-ATP8-ATP6-COX3-trnG fragment is the most conserved region, whereas the region near the control region is the rearrangement hotspot in Ixodidae mitogenomes. The phylogenetic trees based on 15 genes provide a very convincing relationship (Ixodes + (Robertsicus + ((Bothriocroton + Haemaphysalis) + (Amblyomma + (Dermacentor + (Rhipicentor + (Hyalomma + Rhipicephalus))))))) with very strong supports. Remarkably, Archaeocroton sphenodonti is embedded in the Haemaphysalis clade with strong supports, resulting in paraphyly of the Haemaphysalis genus, so in-depth morphological and molecular studies are essential to determine the taxonomic status of A. sphenodonti and its closely related species. Our results provide new insights into the molecular phylogeny and evolution of hard ticks, as well as basic data for population genetics assessment and efficient surveillance and control for the giant panda-infesting ticks.

Neutrophils contain an assembly of granules destined for regulated secretion, each granule type with distinct constituents formed before terminal differentiation. The earliest granules are designated azurophil (primary), followed in time by specific (secondary), and gelatinase granules as well as secretory vesicles. Transcription factors regulate the genes for the granule proteins to ensure that expression of the gene products to be stored in different organelles is separated in time. Similar to lysosomal enzymes, many granule proteins, in particular those of the heterogeneous azurophil granules, are trimmed by proteolytic processing into mature proteins. Rodent myeloid cell lines have been utilized for research on the processing and targeting of human granule proteins after transfection of cDNA. Results from extensive work on the hematopoietic serine proteases of azurophil granules, employing in vitro mutagenesis, indicate that both an immature and a mature conformation are compatible with targeting for storage in granules. On the other hand, the amino-terminal propeptide of myeloperoxidase facilitates both the export from the endoplasmic reticulum and targeting for storage in granules. Similarly, targeting of defensins rely on an intact propeptide. The proteolytic processing into mature granule protein is most commonly a post-sorting event. Mis-sorting of specific granule proteins into azurophil or lysosome-like granules can result in premature activation and degradation, but represents a potential for manipulating the composition and function of neutrophil granules.

Bulbophyllum guniuensis W.Y. Ni & J.W. Shao, a new species of Orchidaceae from Anhui Province, eastern China, is described and illustrated. This new species is similar to B. henanense in overall plant size and leaf morphology, but differs from the latter by the length of the scape and the morphology of the lateral sepals and lip. B. guniuensis is also similar to B. hirundinis in margin fimbriate-ciliate, 3-veined dorsal sepal and petals, but differs from it in oblique oblong (vs. linear) lateral sepals and pale yellow to orange yellow (vs. purplish-red to yellow) flowers.

A new species, Polygonatum praecox Y.F.Hu & J.W.Shao (Asparagaceae), is described and illustrated. This species is similar to P. cyrtonema, P. odoratum and P. caulialatum, but can be distinguished from P. cyrtonema by its racemose inflorescence, cylindrical hairless filaments and apex without a retrorse spur; from P. odoratum by its stout moniliform rhizome, straight stem and longer (1.7-2.2 cm long) floral tube; and from P. caulialatum by its upper part straight stem, yellowish-green corolla, lobes excurved and earlier flowering. The complete chloroplast genome of this new species is 155,115-155,256 bp in length. Phylogenetic analysis revealed that P. praecox is not genetically related to the above three morphological similar species, but is closely related to the two European species (P. multiforum and P. latifolium). This species is relatively common in mid-eastern China and has previously been confused with P. cyrtonema. As its wild resources have decreased in recent years due to over-exploitation for medicinal or edible purposes, we classify it as Near Threatened (NT) according to the IUCN Red List Criteria.

One strategy to protect endangered species, and improve the quality of habitat to meet the needs of both the wildlife and human communities that rely on large protected areas (such as national park), is by zoning its management for multiple uses. We assessed whether multi-use zoning of the Giant Panda National Park (GPNP) could achieve the goal of protecting the panda population and its habitat, while also promoting community development. We integrate panda presence data, human disturbance distribution, and environmental factors to evaluate panda habitat suitability, the effectiveness of zoning designations, and the impact of human disturbance on panda habitat. Our results show that panda habitat suitability has been partially improved, as certain areas of increased in suitability or stabilized (maintained suitability) across the research region between 2001–2003 and 2011–2013, based on the 3rd and 4th national surveys of the giant panda. Most of the optimum and suitable habitat for panda were located in the core protection area of the GPNP. However, the optimum habitat in the general control area is often located at the junction with the core protection area, indicating a particular need to strengthen management in these areas. Meanwhile, the encounter rates of livestock grazing were highest in optimum habitat and unsuitable habitat. As such, particular attention needs to be paid to the pressures on wildlife caused by human disturbances, such as livestock grazing, in the general control area. Our analyses and these findings have important implications for giant panda conservation and GPNP construction.

催产素(oxytocin,OT)是能够对社会关系和共情能力产生重要影响的肽类激素,通过与其受体(oxytocin receptor,OTR)结合而发挥作用(Crockford et al.,2013).对抚育幼体的啮齿类雌性动物,分娩时子宫的收缩会刺激下丘脑处的催产素神经元释放催产素,从而影响母性行为的产生,母性攻击行为可能表现得更明显(Pedersen and Boccia,2003).在妊娠和分娩期间,催产素水平升高则会与产后母婴关系更为亲密(Levine et al.,2007;Feld-man et al.,2010).分娩时释放的催产素可以刺激母性行为迅速出现,如母体舔舐幼仔行为(Kojima and Alberts,2011).哺乳动物催产素具有较为稳定的昼夜变化,这种相对稳定的分泌模式与其行为之间具有紧密的联系(Forsling et al.,1998;Blagrove et al.,2012).

Large-scale molecular phylogenetic studies of the avian order Strigiformes have been performed, and numerous mitochondrial genomes have been determined. However, their intergeneric relationships are still controversial, and few comprehensive comparative analyses of mitochondrial genomes have been conducted on Strigiformes. In this study, the mitochondrial genome of Otus lettia was determined and compared with other Strigiformes. The O. lettia mitochondrial genome was 16,951 bp in size. For Strigiformes, atp8 can be used as a suitable molecular marker for population genetic diversity, while cox1 is a candidate barcoding marker for species identification. All protein-coding genes may be under strong purifying selection pressure, and one extra cytosine insertion located in nad3 is common to all owls except Tyto longimembris, T. alba, and Athene noctua. Four different mitochondrial gene arrangement types were found among the Strigiformes mitogenomes, and their evolutionary relationship between each other can be perfectly explained by the tandem duplication and random loss model. The phylogenetic topologies using the mitochondrial genomes showed that target species O. lettia had a closer relationship with O. scops + O. sunia than O. bakkamoena, the genus Glaucidium was paraphyletic, and the Ninox clade was located at the basal position of Strigidae lineage. Our phylogenetic trees also supported the previous recommendations that Sceloglaux albifacies, Ciccaba nigrolineata, and Ketupa flavipes should be transferred to Ninox, Strix, and Bubo, respectively. These findings will be helpful in further unraveling the mitochondrial evolution and phylogeny of Strigiformes.

Background Lineage 4 of Mycobacterium tuberculosis complex (MTBC), mainly epidemic in Europe and Americas, presents in high proportions in South China and is believed to enter China around the 13th century, when the important human migratory events of the Maritime Silk Road and “Huguang Filling Sichuan” population migration happened in China. This study was to explain the coincidence of these two events with lineage 4’s high proportion in South China. Methods Based on the spatial interpolation analysis of the genotyping data of 25,575 MTBC isolates, the distribution of lineage 4 was compared with that of targeted surname populations and the Maritime Silk Road’s main ports. Results The results showed that lineage 4 distribution in China could be mapped to the regions affected by “Huguang Filling Sichuan” population migration; while the distribution of lineage 4’s two sub-lineages in Asia, Europe, Africa and Oceania could be best explained by the Maritime Silk Road. Conclusion Our results suggest that these two events might pose a crucial shared influence, leading to the greater incidence of lineage 4 in South China. And this may contribute to our better understanding of the prevailing tuberculosis landscape in China and facilitate the epidemiological investigations and tracking of emerging MTBC clones.

Giant pandas (Ailuropoda melanoleuca) possess highly specialized reproductive characteristics, but the maternal immune changes during reproduction are largely unclear. Here, 20 blood transcriptomes were used to determine immune changes at four key phases of giant panda reproduction, and a total of 4640 differential expression genes were identified. During estrus, six immune-related genes (TLR4, IL1B, SYK, SPI1, CD80, and ITK) were identified as hub genes. The up-regulation of the TLR family genes (TLR4, TLR5, TLR6, and TLR8) and inflammatory response related genes (IL1B) may reflect innate immune enhancement and local tissue remodeling events, while the up-regulation of SYK and SPI1, and the down-regulation of CD80 and ITK suggested that the enhanced humoral immunity and inhibited cellular immunity of female giant pandas during estrus. During early pregnancy, antigen presentation related genes and proinflammatory cytokine (IL1B) were down-regulated. This may indicate that partial immune functions were suppressed in early pregnancy to achieve immune tolerance, including reducing inflammatory to protect embryos. By the late pregnancy, the antiviral related genes were upregulated to strengthen defenses against external pathogen infection. KLRK1, which acts as a primary activation receptor for NK cells, was down regulated in estrus and pregnancy, suggesting that the activities of NK cells were inhibited, and KLRK1 may play a key role in the regulation the activities of pbNK cells during reproduction of giant pandas. Our results showed that there was no significant immune change in lactating females (post-natal 2 months) compared to anestrus females. This is the first time to observe the immune changes of giant panda during the breeding period and our data is expected to provide valuable resources for further studies on reproductive immunology of giant pandas.

The Canine Distemper Virus (CDV) is a high fatal virus to the giant panda (Ailuropoda melanoleuca), where CDV vaccination is a key preventative measure in captive giant pandas. However, the immune response of giant pandas to CDV vaccination has been little studied. In this study, we investigated the blood transcriptome expression profiles of five giant panda cubs after three inoculations, 21 days apart. Blood samples were collected before vaccination (0 Day), and 24 h after each of the three inoculations; defined here as 1 Day, 21  Day, and 42  Day. Compared to 0 Day, we obtained 1262 differentially expressed genes (DEGs) during inoculations. GO and KEGG pathways enrichment analysis of these DEGs found 222 GO terms and 40 pathways. The maximum immune-related terms were enriched by DEGs from comparisons of 21  Day and 0 Day. In the PPI analysis, we identified RSAD2, IL18, ISG15 immune-related hub genes from 1 Day and 21 Day comparison. Compared to 0 Day, innate immune-related genes, TLR4 and TLR8, were up-regulated at 1 Day, and the expressions of IRF1, RSAD2, MX1, and OAS2 were highest at 21  Day. Of the adaptive immune-related genes, IL15, promoting T cell differentiation into CD8+T cells, was up-regulated after the first two inoculations, IL12β, promoting T cell differentiation into memory cells, and IL10, promoting B cell proliferation and differentiation, were down-regulated during three inoculations. Our results indicated that the immune response of five giant panda cubs was strongest after the second inoculation, most likely protected against CDV infection through innate immunity and T cells, but did not produce enough memory cells to maintain long-term immunity after CDV vaccination.

Cathartidae is a small family of large-bodied carrion-feeding birds, of which the turkey vulture (Cathartes aura, Cathartidae) is the most widespread distributed. To investigate the chemoreception system, detoxification system, and immune system in the turkey vulture, we compared its genome to 14 other avian genomes. Comparative genomics demonstrated the expansion in the chemoreception system, especially the olfactory receptors, while the genes in the detoxification system of the turkey vulture did not show apparent expansion. We identified five positively selected genes associated with the immune system in the turkey vulture, which was likely to strengthen the immune defense against pathogenic invasion. Functional enrichment analysis indicated that many positively selected genes were involved in the regulation of immune system processes, implying important reorganization of the immune system in the turkey vulture. The turkey vulture-specific missense mutations were found in one positively selected gene (BCL6), and all the missense mutations were classified as deleterious by PolyPhen-2, possibly contributing to immune adaptation to the carrion feeding. Furthermore, we identified four turkey vulture-specific missense mutations in three β-defensin genes of the turkey vulture, which was an indispensable part in the innate immunity (a natural barrier against invasive microbes including bacteria, fungi, and viruses). Our genomic analyses in the turkey vulture provided insights into the genetic signatures of the adaptation to the carrion feeding.