Effect of different inflammation states on the antimicrobial components in milk of goat udders after milking cessation.

The aim of this study was to examine the effects of milking cessation under different inflammatory conditions on the changes in antimicrobial components in milk and the process of mammary gland involution. Twenty udder halves were divided into two groups: those with (LPS) and without (control) lipopolysaccharide infusion, followed by cessation of milking for 8 weeks. Milk samples were collected weekly. Udder tissue was collected 4 weeks after milking cessation to measure the area of the lobule and connective tissue. After milking cessation, the somatic cell count (SCC) in the control group increased, whereas that in the LPS group did not. Lactoferrin (LF) and cathelicidin (Cath)-2 concentrations increased in both groups, whereas only LF was significantly lower in the LPS group than in the control group at week 4. The Cath-7 and S100A8 concentrations were significantly lower in the LPS group than in the control group. The lobule area was higher, and the connective tissue area was lower in the LPS group than in the control group. These results indicate that inflammation at milking cessation decreased the concentrations of some antimicrobial components and interfered with mammary gland involution. Therefore, animals with mastitis should recover prior to the onset of the dry period.

A moderate anticoccidial effect of cedrol on Eimeria tenella in broiler chickens.

As drug-resistant strains of Eimeria have emerged and concerns about drug residues in poultry have grown, there is renewed interest in identifying natural alternatives to control coccidiosis. Cedrol, a natural sesquiterpene alcohol, was used in this study to test anticoccidial efficacy in chicks. Both the control and treatment groups were orally challenged with 2 × 104 oocysts per chicken. Chicks administered with cedrol had reduced oocyst count, an increase in the relative weight gain rate of chicks, and a decrease in severe swelling of the cecum. Based on the above, ACI was calculated and the cedrol group reached moderate anti-coccidial activity (169.34). In chickens treated with cedrol, there were no changes in serum biochemical parameters, but oxidative stress biomarkers and cytokine levels associated with anticoccidial response were altered. These changes suggest that the administered concentration of cedrol did not have any adverse effects on the chickens while enhancing their antioxidant capacity and immunity, leading to an improved anticoccidial ability. In conclusion, this study shows that the addition of cedrol in poultry production has an anticoccidial effect and successfully improves growth performance during the growth period.

Artificial Spider Silk with Buckled Sheath by Nano-Pulley Combing.

The axial orientation of molecular chains always results in an increase in fiber strength and a decrease in toughness. Here, taking inspiration from the skin structure, artificial spider silk with a buckled sheath-core structure is developed, with mechanical strength and toughness reaching 1.61 GPa and 466 MJ m-3 , respectively, exceeding those of Caerostris darwini silk. The buckled structure is achieved by nano-pulley combing of polyrotaxane hydrogel fibers through cyclic stretch-release training, which exhibits axial alignment of the polymer chains in the fiber core and buckling in the fiber sheath. The artificial spider silk also exhibits excellent supercontraction behavior, achieving a work capacity of 1.89 kJ kg-1 , and an actuation stroke of 82%. This work provides a new strategy for designing high-performance and intelligent fiber materials.

Identification and Characterization of Eimeria tenella Rhoptry Protein 35 (EtROP35).

Rhoptry proteins (ROPs) of Apicomplexa are crucial secreted virulence factors and sources of vaccine candidates. To date, Eimeria tenella ROPs are not well studied. This study identified and characterized a novel E. tenella ROP (EtROP35), which showed the highest levels among 28 putative ROPs in previous sporozoite and merozoite transcriptomes. Sequence analysis showed that EtROP35 contains an N-terminal secretory signal and a protein kinase domain including eight conserved ROP35-subfamily motifs. Subsequent experiments confirmed that it is a secretory protein. Subcellular localization revealed it localized at the apical end of the sporozoites and merozoites, which was consistent with the ROPs of other Apicomplexan parasites. To further understand the biological meaning of EtROP35, expression levels in different developmental stages and sporozoite invasion-blocking assay were investigated. EtROP35 showed significantly higher levels in sporozoites (6.23-fold) and merozoites (7.00-fold) than sporulated oocysts. Sporozoite invasion-blocking assay revealed that anti-EtROP35 polyclonal antibody significantly reduced the sporozoite invasion rate, suggesting it might participate in host cell invasion and be a viable choice as a vaccine candidate. The immunological protective assays showed that EtROP35 could induce a high level of serum IgY and higher mean body weight gain, and lower cecum lesion score and oocysts excretion than the challenged control group. These data indicated that EtROP35 had good immunogenicity and may be a promising vaccine candidate against E. tenella.

Identification and characterization of Eimeria tenella EtTrx1 protein.

Thioredoxin (Trx) is a widespread protein regulator of redox reactions in all organisms. It operates together with NADPH and thioredoxin reductase as a general protein disulfide catalytic system. Recently, Trx has been found to be related to the process by which apicomplexan protozoa invade host cells. In this study, Eimeria tenella thioredoxin (EtTrx1) was identified and its gene structural features, expression levels at different developmental stages, localization in sporozoites, roles in adhesion and invasion, and immunogenicity were investigated. Sequence analysis indicated that EtTrx1 contains a Trx domain with a WCGPC motif in 29-33 aa and a typical Trx fold, and belongs to thioredoxin family. EtTrx1 was detected on the surface of sporozoites using anti-EtTrx1 polyclonal antibodies under non-permeabilized conditions by indirect immunofluorescence assay (IFA) and also in a secretion form. EtTrx1 protein was highly transcribed and expressed in merozoites and sporozoites by quantitative PCR and western blot. The attachment assay showed that the adherence rates of yeast cells expressing EtTrx1 on the surface to host cells were 3.1-fold higher than those of the blank control. Specific anti-EtTrx1 antibodies inhibited the invasion of sporozoites into DF-1 cells. The highest inhibition rate was up to 36.75% compared to the control group. Immunization with recombinant EtTrx1 peptides also showed significant protection against lethal infections in chickens. It could offer moderate protective efficacy (Anticoccidial Index [ACI]: 163.70), induce humoral responses, and be an effective candidate for the development of new vaccines.

The Impacts of Environmental Dynamism on Chinese Tour Guides' Sustainable Performance: Factors Related to Vitality, Positive Stress Mindset and Supportive Policy.

Although previous research shows great interest in improving the sustainability of organizations' performance, little is known about individual sustainable performance, especially for special groups such as tour guides. Drawing on the Conservation of Resources (COR) theory, this study aimed to investigate the effect of environmental dynamism caused by COVID-19 on tour guides' sustainable performance and mediating role of vitality and intervention mechanism in this relationship. Adopting a quantitative research method, we collected data from 382 professional tour guides in China via three surveys. The Structural Equation Model (SEM) and PROCESS were used to test the hypotheses. The results revealed that: (1) environmental dynamism was negatively related to tour guides' sustainable performance and (2) vitality at work mediated this negative effect; (3) a positive stress mindset moderated the relationship between environmental dynamism and vitality; (4) supportive policy's moderating role in the relationship of vitality and sustainable performance was not significant. The above conclusions contribute to the literature about the external environment, emotional state, performance management and application boundary of COR theory in the context of the COVID-19 pandemic.

Tuning the reversibility of hair artificial muscles by disulfide cross-linking for sensors, switches, and soft robotics.

Tensile and torsional artificial muscles from biocompatible and biodegradable materials are highly desired for soft robotics, sensors, and controllers in bio-related applications. Twisted fibers can be used to prepare tensile and torsional artificial muscles, while torsional tethering is always required to avoid release of the inserted twist, which adds complexity to the device design. Moreover, the tuning of the reversibility of twisted fiber artificial muscles has not been realized. Here disulfide cross-linking was used to prepare novel tether-free hygroresponsive tensile and torsional fiber artificial muscles in twisted hair fibers. Increasing the cross-linking level converted the fiber artificial muscle from irreversible to reversible actuation. Different types of actuations including rotation, contraction, and elongation were realized for the twisted, the homochirally coiled, and the heterochirally coiled hair fibers, respectively. A reversible torsional fiber artificial muscle showed 122.4° mm-1 rotation, homochiral and heterochiral fiber artificial muscles showed 94% contraction and 3000% elongation, respectively, and a maximum work capacity and energy density of 6.35 J kg-1 and 69.8 kJ m-3, respectively, were realized, on exposure to water fog. This work provides a new strategy for preserving the inserted twist in bio-fiber artificial muscles and for tuning of muscle reversibility, which show application perspectives in biocompatible smart materials, sensors, and robotics.

Astaxanthin Z-isomer-rich diets enhance egg yolk pigmentation in laying hens compared to that in all-E-isomer-rich diets.

The effects of feeding diets containing astaxanthin with different Z-isomer ratios to laying hens on egg qualities, such as astaxanthin concentration in egg yolk and yolk color, were investigated. As the astaxanthin source, a natural microorganism Paracoccus carotinifaciens was used. Astaxanthin with different Z-isomer ratios was prepared by thermal treatment with different conditions and then added to the basal diet at a final astaxanthin concentration of 8 mg/kg. We found that, as the Z-isomer ratios of astaxanthin in the diet increased, the astaxanthin concentration in egg yolk and the yolk color fan score also increased significantly. Importantly, feeding a 50.6% Z-isomer ratio diet increased astaxanthin concentration in egg yolk by approximately fivefold and the color fan score by approximately 2 compared to that in hens fed an all-E-isomer-rich diet. Moreover, we showed that feeding Z-isomer-rich astaxanthin to laying hens increased plasma astaxanthin concentration by more than five times in comparison to that in hens fed an all-E-isomer-rich diet. These results indicate that Z-isomers of astaxanthin have higher bioavailability than that of the all-E-isomer and thus they exhibit greater egg yolk-accumulation efficiency.

Escape or stay? Effects of haze pollution on domestic travel: Comparative analysis of different regions in China.

Haze pollution has significant impacts on tourist perception and behaviour, including a sharp increase in risk perception and a decline in tourism experience quality. However, given the intervention of multiple factors, whether these impacts necessarily have a negative effect on the overall scale of regional tourism remains unknown. Hence, this paper explored the overall effect of haze pollution on domestic travel. Using 28 major cities in China as examples, we employed a two-way fixed effect panel model to investigate this issue. Combined with the comparisons between the results of different subgroups, including high cities, medium cities, low cities, outbreak cities and non-outbreak cities, this study found that there was no significant effect of haze concentration on domestic travel, but public awareness of haze pollution had a significant positive effect on that. Meanwhile, public awareness exerted a negative moderating effect of haze concentration and domestic travel. The findings are beneficial for understanding the new situation faced by the tourism industry, and several suggestions are provided for policy makers and travel agencies.