Red pandas with different diets and environments exhibit different gut microbial functional composition and capacity.

The red panda (Ailurus fulgens) is a distinctive mammal known for its reliance on a diet primarily consisting of bamboo. The gut microbiota and overall health of animals are strongly influenced by diets and environments. Therefore, conducting research to explore the taxonomical and functional variances within the gut microbiota of red pandas exposed to various dietary and environmental conditions could shed light on the dynamic complexities of their microbial communities. In this study, normal fecal samples were obtained from red pandas residing in captive and semi-free environments under different dietary regimes and used for metabolomic, 16S rRNA, and metagenomic sequencing analysis, with the pandas classified into four distinct cohorts according to diet and environment. In addition, metagenomic sequencing was conducted on mucus fecal samples to elucidate potential etiological agents of disease. Results revealed an increased risk of gastrointestinal diseases in red pandas consuming bamboo shoots due to the heightened presence of pathogenic bacteria, although an increased presence of microbiota-derived tryptophan metabolites appeared to facilitate intestinal balance. The red pandas fed bamboo leaves also exhibited a decrease in gut microbial diversity, which may be attributed to the antibacterial flavonoids and lower protein levels in leaves. Notably, red pandas residing in semi-free environments demonstrated an enriched gut microbial diversity. Moreover, the occurrence of mucus secretion may be due to an increased presence of species associated with diarrhea and a reduced level of microbiota-derived tryptophan metabolites. In summary, our findings substantiate the influential role of diet and environment in modulating the gut microbiota of red pandas, offering potential implications for improved captive breeding practices.

Design of carboxymethylcellulose-conjugated polymeric prodrug micelles for enhanced in vivo performance of docetaxel.

Docetaxel (DTX) has become one of the most important cytotoxic drugs to treat cancer; nevertheless, its poor hydrophilicity and non-specific distribution of DTX lead to detrimental side effects. In this article, we devised carboxymethylcellulose (CMC)-conjugated polymeric prodrug micelles (mPEG-CMC-DTX PMs) for DTX delivery. The ester-bonded polymeric prodrug, mPEG-CMC-DTX, was synthesized and exhibited the capacity for self-assembling into polymeric micelles. The CMC is profusely substituted and acetylated to promote the coupling rate of DTX. Covalent binding of DTX and CMC through an ester bond can be hydrolyzed to dissociate the bond under the action of esterase in the tumor. The mPEG-CMC-DTX PMs displayed promoted drug loading (>50 %, wt), commendable stability, and sustained release behavior in vitro. The gradual release of the prodrug amplified the selectivity of cytotoxicity between normal cells and tumor cells, mitigating the systemic toxicity of mPEG-CMC-DTX PMs and enabling dose intensification. Notably, mPEG-CMC-DTX PMs demonstrated a superior antitumor efficacy and low systemic toxicity due to the elevated tolerance dosage (even at 40 mg/kg DTX). In summation, mPEG-CMC-DTX PMs harmonized the antitumor efficacy and toxicity of DTX. In essence, innovative perspectives for the rational design of CMC-conjugated polymeric prodrug micelles for the delivery of potently toxic drugs were proffered.

Bamboo Plant Part Preference Affects the Nutrients Digestibility and Intestinal Microbiota of Geriatric Giant Pandas.

Bamboo part preference plays a critical role in influencing the nutrient utilization and gastrointestinal microbiota composition of captive giant pandas. However, the effects of bamboo part consumption on the nutrient digestibility and gut microbiome of geriatric giant pandas remain unknown. A total of 11 adult and 11 aged captive giant pandas were provided with bamboo shoots or bamboo leaves in the respective single-bamboo-part consumption period, and the nutrient digestibility and fecal microbiota of both adult and aged giant pandas in each period were evaluated. Bamboo shoot ingestion increased the crude protein digestibility and decreased the crude fiber digestibility of both age groups. The fecal microbiome of the bamboo shoot-fed giant pandas exhibited greater alpha diversity indices and significantly different beta diversity index than the bamboo leaf-fed counterparts regardless of age. Bamboo shoot feeding significantly changed the relative abundance of predominant taxa at both phylum and genus levels in adult and geriatric giant pandas. Bamboo shoot-enriched genera were positively correlated with crude protein digestibility and negatively correlated with crude fiber digestibility. Taken together, these results suggest that bamboo part consumption dominates over age in affecting the nutrient digestibility and gut microbiota composition of giant pandas.

Antimicrobial resistance, serogroups, virulence gene profiles and MLST of Escherichia coli from giant panda.

Escherichia coli is a major bacterial pathogen which causes diarrhea in the giant panda. This study investigated the biological characteristics of 100 E. coli strains isolated from fecal samples collected from 100 captive giant pandas of different age groups and sexes. A standard Kirby-Bauer disk diffusion antimicrobial susceptibility test was performed with the isolates and we then further evaluated the antibiotic resistance genes (ARGs) by high-throughput quantitative PCR. Additionally, we then analyzed O serogroups through a slide agglutination test, virulence genes and the multi-locus sequence typing (MLST) by PCR. Antimicrobial susceptibility testing demonstrated that the 100 E. coli strains were mainly resistant to ENR (68%), AM (56%), IPM (55%), AMX (54%) and CA (52%), but were susceptible to MEM and FOX. The resistance to TZP, AK, FEP, CAZ, AMS, AZM, AT and IPM was significantly related to age (p < 0.05); the resistance rate of E. coli isolated from female giant pandas to N was significantly higher than in males (p < 0.05). Forty-five different types of ARGs were found, which included a total of 2,258 ARGs, in the 100 E. coli isolates. The top 10 of detection rate of ARGs were: acrA-04, acrA-05, aacC, blaCTX-M-04, ampC-04, blaSHV-01, blaTEM, sul2, blaOXY, tetA-02. ARGs aac (6')I1, blaCTX-M-03, tetD-02, blaSHV-02 and blaOXY were significantly related to age (p < 0.05), blaSHV-02, blaNDM and ampC-04 were related to sex (p < 0.05). Twelve different O serogroups from 32 E. coli isolates were distinguished, including O4, O8, O9, O15, O18, O20, O55, O88, O112, O157, O158, and O167. The most prevalent O serotype was O20, but O28, O45, O101, O149, and O152 were not detected. Fourteen different types of virulence genes were detected in the 100 E. coli isolates, of which papA (99%) were highly detected, while hlyA, elt and estA were not detected. MLST showed that 41 STs, which had one CCs and six groups with SLVs, in the 100 E. coli strains were identified, the main type was ST37. Our results advocate the need of strict biosecurity and surveillance programs in order to prevent the spread of pathogenic bacteria in the captive giant panda population.

PLANT NATRIURETIC PEPTIDE A and Its Putative Receptor PNP-R2 Antagonize Salicylic Acid-Mediated Signaling and Cell Death.

The plant stress hormone salicylic acid (SA) participates in local and systemic acquired resistance, which eventually leads to whole-plant resistance to bacterial pathogens. However, if SA-mediated signaling is not appropriately controlled, plants incur defense-associated fitness costs such as growth inhibition and cell death. Despite its importance, to date only a few components counteracting the SA-primed stress responses have been identified in Arabidopsis (Arabidopsis thaliana). These include other plant hormones such as jasmonic acid and abscisic acid, and proteins such as LESION SIMULATING DISEASE1, a transcription coregulator. Here, we describe PLANT NATRIURETIC PEPTIDE A (PNP-A), a functional analog to vertebrate atrial natriuretic peptides, that appears to antagonize the SA-mediated plant stress responses. While loss of PNP-A potentiates SA-mediated signaling, exogenous application of synthetic PNP-A or overexpression of PNP-A significantly compromises the SA-primed immune responses. Moreover, we identify a plasma membrane-localized receptor-like protein, PNP-R2, that interacts with PNP-A and is required to initiate the PNP-A-mediated intracellular signaling. In summary, our work identifies a peptide and its putative cognate receptor as counteracting both SA-mediated signaling and SA-primed cell death in Arabidopsis.

Uncoupled Expression of Nuclear and Plastid Photosynthesis-Associated Genes Contributes to Cell Death in a Lesion Mimic Mutant.

Chloroplast-to-nucleus retrograde signaling is essential for the coupled expression of photosynthesis-associated nuclear genes (PhANGs) and plastid genes (PhAPGs) to ensure the functional status of chloroplasts (Cp) in plants. Although various signaling components involved in the process have been identified in Arabidopsis (Arabidopsis thaliana), the biological relevance of such coordination remains an enigma. Here, we show that the uncoupled expression of PhANGs and PhAPGs contributes to the cell death in the lesion simulating disease1 (lsd1) mutant of Arabidopsis. A daylength-dependent increase of salicylic acid (SA) appears to rapidly up-regulate a gene encoding SIGMA FACTOR BINDING PROTEIN1 (SIB1), a transcriptional coregulator, in lsd1 before the onset of cell death. The dual targeting of SIB1 to the nucleus and the Cps leads to a simultaneous up-regulation of PhANGs and down-regulation of PhAPGs. Consequently, this disrupts the stoichiometry of photosynthetic proteins, especially in PSII, resulting in the generation of the highly reactive species singlet oxygen (1O2) in Cps. Accordingly, inactivation of the nuclear-encoded Cp protein EXECUTER1, a putative 1O2 sensor, significantly attenuates the lsd1-conferred cell death. Together, these results provide a pathway from the SA- to the 1O2-signaling pathway, which are intertwined via the uncoupled expression of PhANGs and PhAPGs, contributing to the lesion-mimicking cell death in lsd1.

Seroprevalence and risk factors of Chlamydia infection in dogs in Southwestern China.

Chlamydia spp. are obligate intracellular bacteria distributed globally, known to cause various forms of diseases in animals and humans. To date, there is limited information about the seroprevalence of Chlamydia and the risk factors associated with Chlamydia infection in dogs in the world. In the present study, a serological survey was undertaken to examine the seroprevalence and risk factors associated with dog chlamydiosis in Yunnan Province, southwestern China. A total of 591 dogs were sampled, antibodies to Chlamydia were determined by indirect hemagglutination assay (IHA). The overall seroprevalence was estimated at 17.6%. The risk factors associated with seroprevalence were determined by a multivariate logistic regression analysis. Gender and age of dogs were not significant in the logistic regression analysis (P>0.05) and left out of the final model. Type and geographical origin of dogs were considered as main risk factors associated with Chlamydia infection, stray dogs (31.37%) were more than 16 times (OR=16.167, 95% CI=6.283-41.599, P<0.01) at risk of acquiring the infection compared to the police dogs (7.62%), while pet dogs (14.41%) had a 3 times (OR=2.968, 95% CI=1.349-6.529, P=0.007) higher risk. Positive dogs were found in 5 districts of Yunnan Province with prevalence ranging from 2.56% to 31.67% except Diqing (0/56). Dogs in Kunming (20.21%) had a 9 times higher risk of being seropositive compared to dogs in Lijiang (2.56%) (OR=9.057, 95% CI=1.211-67.714, P=0.032), although no regional differences were found in other 4 administrative divisions compared to Lijiang (P>0.05). Our study revealed a widespread and high prevalence of Chlamydia infection in dogs in Yunnan Province, southwestern China, with higher exposure risk in stray dogs and distinct geographical distribution. These findings suggest the potential importance of dogs in the transmission of zoonotic Chlamydia infection, and thus Chlamydia should be taken into consideration in diagnosing dog diseases.

Characterization of Fasciola samples by ITS of rDNA sequences revealed the existence of Fasciola hepatica and Fasciola gigantica in Yunnan Province, China.

On mainland China, liver flukes of Fasciola spp. (Digenea: Fasciolidae) can cause serious acute and chronic morbidity in numerous species of mammals such as sheep, goats, cattle, and humans. The objective of the present study was to examine the taxonomic identity of Fasciola species in Yunnan province by sequences of the first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA (rDNA). The ITS rDNA was amplified from 10 samples representing Fasciola species in cattle from 2 geographical locations in Yunnan Province, by polymerase chain reaction (PCR), and the products were sequenced directly. The lengths of the ITS-1 and ITS-2 sequences were 422 and 361-362 base pairs, respectively, for all samples sequenced. Using ITS sequences, 2 Fasciola species were revealed, namely Fasciola hepatica and Fasciola gigantica. This is the first demonstration of F. gigantica in cattle in Yunnan Province, China using a molecular approach; our findings have implications for studying the population genetic characterization of the Chinese Fasciola species and for the prevention and control of Fasciola spp. in this province.

Seroprevalence of Toxoplasma gondii antibodies from slaughter pigs in Chongqing, China.

Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii which infects most genera of warm-blooded animals, including humans. The objective of this investigation is to evaluate the seroprevalence of toxoplasmosis in pigs in Chongqing Municipality, southwest China. Slaughterhouse pigs' serum samples collected from six different regions in Chongqing were assayed for T. gondii antibodies by an indirect hemagglutination test. The average seroprevalence of T. gondii were found in 30.6% (278/908) in slaughter pigs, ranging from 21.6% to 40.9% among different sampling sites. The results indicated that toxoplasmosis in swine of Chongqing Municipality was relatively serious, and the pork may be an important source for human infection with T. gondii. Comprehensive measures are needed to strengthen further prevention and control of the disease in Chongqing.