Livestock grazing is associated with the gut microbiota and antibiotic resistance genes in sympatric plateau pika (Ochotona curzoniae).

With the overuse of antibiotics in health care and animal husbandry, antibiotic resistance becomes a serious threat to public health. Antibiotic residues from veterinary medicine have increased the dissemination of antibiotic resistance genes (ARGs) by horizontal gene transfer globally, leading to the enrichment of ARGs in wildlife. Plateau pika (Ochotona curzoniae) is a small herbivore endemic to the Qinghai-Tibetan Plateau. Previous studies reveal that pika evolves a coprophagy behavior toward cohabitated yak, which makes the pika population a potential reservoir of ARGs. Yet, little is known about the resistome of pika under different grazing intensities. Here, we sampled the cecum content of pika from three different grazing intensity areas in the Qinghai-Tibetan Plateau to evaluate the effect of grazing on its gut microbiota and resistome. By using the 16S full-length amplicon and metagenomic sequencing, our study revealed that livestock grazing significantly altered the gut microbial community of plateau pika as compared to prohibited grazing areas. We found bacterial lineage Prevotellaceae, Lachnospirales, and RF39 increased in grazing areas. Analysis of the resistome revealed that pika from continuous grazing areas enriched a higher abundance of colistin (MCR) and streptogramin (vat) resistance genes. Moreover, we observed significant correlations between the gut microbial community, ARGs, and mobile genetic element profiles, hinting that pika gut microbiota was an important shaping force of the resistome. In future studies, the continuous monitoring of wildlife gut resistome and environmental antibiotic residues is imperative for a better understanding and for tackling the horizontal gene transfer of ARGs across the wildlife-livestock interface.

Enhancing organic selenium content and antioxidant activities of soy sauce using nano-selenium during soybean soaking.

Nano-selenium has a greater potential than inorganic selenium in preventing selenium-deficiency diseases due to its higher safety. In this study, spherical nano-selenium particles (53.8 nm) were prepared using sodium selenite, ascorbic acid and chitosan. Selenium-enriched soy sauces were prepared by soaking soybean in nano-selenium and sodium selenite solutions (2-10 mg/L), respectively. Total selenium and organic selenium contents of soy sauces prepared by nano-selenium and sodium selenite were increased by 32-191-fold and 29-173-fold compared to the control (without selenium), and organic selenium accounted for over 90% of total selenium. Soy sauce prepared using 6 mg/L nano-selenium had the strongest antioxidant activities, which were 9.25-28.02% higher than the control. Nano-selenium (6 mg/L) markedly enhanced the koji's enzyme activities (9.76-33.59%), then the latter promoted the release of total phenolics (27.54%), total flavonoids (27.27%) and the formation of free amino acids (16.19%), Maillard reaction products (24.50%), finally the antioxidant activities of selenium-enriched soy sauce were enhanced.

Genomic insights into zokors' phylogeny and speciation in China.

The phylogeny and speciation of subterranean zokors in China are unclear, as previous studies on morphology and limited molecular markers have generated conflicting results. This study unraveled the complex evolutionary history of eight zokor species in China based on de novo assembly at chromosome level and whole-genome sequencing of 23 populations. We found extensive phylogenetic discordances between nuclear and mitochondrial phylogenies, and different coalescent phylogenies, which could be explained by introgression and incomplete lineage sorting (ILS). The recent Qinghai-Tibet Plateau uplift (∼3.60 million y ago; Mya) drove Eospalax to speciate into clade A and clade B (∼3.22 Mya), and discordant phylogenies in this node were mainly attributed to introgression rather than ILS. Clade A rapidly diverged into three lineages due to geographical isolation and glaciation, while glaciation and C4 plant expansion contributed to the speciation of clade B. ILS contributed to the discordances of two rapidly radiated nodes rather than introgression. The effective population sizes (Ne's) of all the species of Eospalax were affected by three glaciations. Ancient polymorphisms and divergence hitchhiking contribute to genomic islands of all the species pairs. Positively selected genes putatively related to specific inhabitation adaptations were identified, such as heart development, neurogenesis, DNA repair, and immune response. Climate, geological tectonism, and C4 vegetation shaped the adaptation and speciation of zokors in China.

Long-Term Effects of Climate Variability on Seed Rain Dynamics of Four Fagaceae Sympatric Species in Qinling Mountains, China.

Seed rain, as the beginning of species dispersal, is a key process for forest structure and regeneration. In this study, the seed rain of four Fagaceae sympatric plant species (Castaneamollissima, Quercus aliena, Quercus variabilis, and Quercus serrata) in the Qinling Mountains were monitored for ten consecutive years, and the responses of seed rain dynamics of the four species to major climatic factors (temperature and precipitation) were analyzed. We found there were significant differences in the seed rain dynamics between C. mollissima of Castanea and the other three species of Quercus in the initial period and end period and the duration of the whole seed rain process among the 10 years. This could indicate to some extent that there was no concentrated flowering and fruiting among different plants of different genera, and they could well avoid fierce competition for similar resources and coexist in the same region. This may also be a reproductive strategy for plants. Seed rain dynamics of different plant species had different sensitivities to climate factors (temperature and precipitation), which indicated that mainly because of their different responses to climate factors, they could well avoid fierce competition for similar climate resources. In addition, the differences in seed rain dropping dynamics could reduce consumption in large numbers by seed predators, thereby promoting their own dispersal and regeneration. All of the above contribute to their better coexistence in the same domain.

Anti-fertility effect of levonorgestrel and/or quinestrol on striped field mouse (Apodemus agrarius): evidence from both laboratory and field experiments.

The effect of combined levonorgestrel (P) and quinestrol (E) on the fertility of striped field mouse (Apodemus agrarius) has not been evaluated. We performed a series of experiments in both the laboratory and field to assess the effect of P and/or E on the fertility of A. agrarius. In the laboratory, to test the time-dependent anti-fertility effects of P and E, as well as their mixtures, 90 male striped field mice were randomly assigned to 6 treatment groups (n = 60), and a control group (n = 30). Mice in 3 treatment groups were administered 1 of the 3 compounds (1 mg⋅kg- 1 [body weight] EP-1, 0.34 mg⋅kg-1 E, 0.66 mg⋅kg-1 P) for 3 successive days (another half for 7 successive days) via oral gavage; mice were then sacrificed 15 and 45 days after initiating the gavage treatment. Our findings indicated that E and EP-1 treatment, but not P or control treatment, significantly decreased the sperm count in the caudal epididymis, as well as the weight of the testes, epididymides, and seminal vesicles. Additionally, fertile female mice mated with E- and EP-1-treated males produced smaller pups. These data indicate that E and EP-1 can induce infertility in male A. agrarius. In the field, the population density of A. agrarius was significantly influenced by EP-1, and the rodent density in the treatment group was lower than that in the control group. Overall, our results indicate that EP-1 is an effective contraceptive in A. agrarius, a dominant rodent species in the farmland.

Seed traits and rodent community interact to determine seed fate: evidence from both enclosure and field experiments.

Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise. However, few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees. We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds. Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents. We found that seeds with heavy weight, thick coat, and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents. These results support both the handling time hypothesis and the high nutrition hypothesis. Surprisingly, we also found that rodents, maybe, preferred to consume seeds with low levels of crude fiber in situ, and to harvest and hoard those with high levels of crude fiber for later consumption. The sympatric rodent species, Cansumys canus, the largest rodent in our study, harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits, while Apodemus draco, the smallest rodent, harvested more Q. serrata seeds with low physical and nutritional traits, and Niviventer confucianus harvested and hoarded more Q. aliena seeds with medium physical and nutritional traits. Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.

Characterization of the aroma-active compounds in black soybean sauce, a distinctive soy sauce.

Black soybean sauce's (BSS) aroma was scarcely investigated, which seriously affected BSS's quality and consumers' preference. Thus the aroma compounds in BSS were characterized using gas chromatography-mass spectrometry/gas chromatography-olfactometry coupling with recombination and omission experiments. Sensory evaluation showed the fruity odor was increased by 63% and the malty, alcoholic, floral, smoky, caramel-like and sour odors were decreased by 24-35% when compared to the control soy sauce (SS, p < 0.05). Totally, 126 volatile compounds, 44 aroma-active compounds and 22 vital aroma-active compounds were identified in BSS. Compared to SS, BSS exhibited a distinctive aroma characteristics which was caused by significantly higher odor activity values (OAVs) of 3-methylbutyl acetate (357%), ethyl propanoate (144%), ethyl 3-methylbutanoate (70%), ethyl 2-methylbutanoate (102%) and lower OAVs of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (52%), 4-hydroxy-2-ethyl-5-methyl-3(2H)-furan-3-one (50%), ethanol (48%), 4-vinylguaiacol (41%), 3-methylthiopropanal (37%), 3-methylbutanol (33%), 4-ethylguaiacol (28%). The results would contribute to BSS's quality control and aroma improvement.

Ougan juice debittering using ultrasound-aided enzymatic hydrolysis: Impacts on aroma and taste.

The optimal sonication conditions (40 kHz, 80 W/L and 60 min) during Ougan juice debittering by Aspergillus niger koji extract were established. Enzymatic hydrolysis degrees of naringin and limonin were enhanced to 89.90% and 36.16%, and enzymatic hydrolysis time was shortened by 33%. Sonication significantly enhanced activities of α-l-rhamnosidases, ß-glucosidases and limoninases from A. niger koji extract and facilitated break of CO bonds in naringin (p < 0.05). These accounted for the enhanced enzymatic hydrolysis degrees and velocities of bitter compounds. Meanwhile, sonication lowered 40%, 7% and 21%, 13%, 11%, 25% of bitter, sour tastes and green, citrus-like, floral, woody notes, but enhanced 18% and 15% of fruity and sweet notes, resulting in 38% and 33% increases in over-all taste and aroma scores. Lowered levels of bitter compounds, organic acids, green, citrus-like, floral, woody aroma compounds and enhanced levels of fruity, sweet aroma compounds caused by sonication accounted for the flavor improvements.

Alteration in oxytocin levels induced by early social environment affects maternal behavior and estrogen receptor alpha in mandarin voles (Microtus mandarinus).

Many studies have shown that the early social environment exerts long-term effects on the brain and also the parental behavior of adults. Oxytocin (OXT) is one of the most important neurotransmitters that regulate social behavior; howerve, whether the early social environment affects parental behavior via OXT remains unclear. Using socially monogamous adult mandarin voles (Microtus mandarinus), the present study found that 1) both paternal deprivation and early social deprivation significantly decreased OXT expression in both the paraventricular hypothalamic nucleus (PVN) and the supraoptic nucleus (SON) of F2 generation offspring; 2) systemic neonatal OXT injection in naïve animals promoted maternal but not paternal behavior in adult F2 offspring; 3) systemic neonatal OXT injection significantly increased ERα expression in both the medial preoptic area (MPOA) and the ventro medial hypothalamic nucleus (VMH) in female but not in male mandarin voles; 4) systemic neonatal administration of an OXT antagonist significantly reduced ERα expression in the bed nucleus of the stria terminalis (BNST), VMH, and the arcuate hypothalamic nucleus (Arc) in females and in all examined brain regions in males. In summary, the obtained data demonstrate that the early social environment could affect OXT level, which in turn leads to long-term effects on ERα expression in relevant brain regions, consequently affecting maternal behavior but not paternal behavior.