Ubiquitination modifications permit the degradation of labelled target proteins with the assistance of proteasomes and lysosomes, which is the main protein degradation pathway in eukaryotic cells. Polyubiquitination modifications of proteins can also affect their functions. De-ubiquitinating enzymes reverse the process of ubiquitination via cleavage of the ubiquitin molecule, which is known as a de-ubiquitination. It was demonstrated that ubiquitination and de-ubiquitination play key regulatory roles in fatty acid transport, de novo synthesis, and desaturation in dairy mammary epithelial cells. In addition, natural plant extracts, such as stigmasterol, promote milk fat synthesis in epithelial cells via the ubiquitination pathway. This paper reviews the current research on ubiquitination and de-ubiquitination in dairy milk fat production, with a view to providing a reference for subsequent research on milk fat and exploring new directions for the improvement of milk quality.

Burkholderia contaminans, an emerging pathogen related to cystic fibrosis, is known to cause potentially fatal infections in humans and ruminants, especially in immunocompromised individuals. However, the immune responses in cows following its infection have not been fully elucidated. In this study, T- and B-lymphocytes-mediated immune responses were evaluated in 15 B. contaminans-induced mastitis cows and 15 healthy cows with multi-parameter flow cytometry. The results showed that infection with B. contaminans was associated with a significant decrease in the number and percentage of B lymphocytes but with a significant increase in the proportion of IgG⁺CD27⁺ B lymphocytes. This indicated that humoral immune response may not be adequate to fight intracellular infection, which could contribute to the persistent bacterial infection. In addition, B. contaminans infection induced significant increase of γδ T cells and double positive (DP) CD4⁺CD8⁺ T cells but not CD4⁺ or CD8⁺ (single positive) T cells in blood. Phenotypic analysis showed that the percentages of activated WC1⁺ γδ T cells in peripheral blood were increased in the B. contaminans infected cows. Interestingly, intracellular cytokine staining showed that cattle naturally infected with B. contaminans exhibited multifunctional TNF-α⁺IFN-γ⁺IL-2⁺B. contaminans-specific DP T cells. Our results, for the first time, revealed a potential role of IgG⁺CD27⁺ B cells, CD4⁺CD8⁺ T cells and WC1⁺ γδ T cells in the defense of B. contaminans-induced mastitis in cows.

Daphnis nerii cypovirus-23 (DnCPV-23) is a new type of cypovirus that has a lethal effect on many species of Sphingidae pests. DnCPV-23 can replicate in Spodoptera frugiperda Sf9 cells, but the replication characteristics of the virus in this cell line are still unclear. To determine the replication characteristics of DnCPV-23 in Sf9 cells, uninfected Sf9 cells and Sf9 cells at 24 and 72 h after DnCPV-23 infection were collected for transcriptome analysis. Compared to uninfected Sf9 cells, a total of 188 and 595 differentially expressed genes (DEGs) were identified in Sf9 cells collected at 24 hpi and 72 h, respectively. KEGG analyses revealed that 139 common DEGs in two treatment groups were related to nutrition and energy metabolism-related processes, cell membrane integrity and function-related pathways, detoxification-related pathways, growth and development-related pathways, and so on. We speculated that these cellular processes might be manipulated by viruses to promote replication. This study provides an important basis for further in-depth research on the mechanism of interaction between viruses and hosts. It provides additional basic information for the future exploitation of DnCPV-23 as a biological insecticide.

This study investigated the effects of fermented Chinese chive (FCC) juice supplementation on growth performance, blood parameters, meat quality, and fresh meat volatile compounds in Small-Tailed Han sheep. Sixty sheep were randomly assigned to a control group (CG; basal diet) or an FCC juice treatment group (TG; basal diet supplemented with 1.0 mL/kg feed offered on an as-fed basis), with three pens per treatment and 10 sheep per pen. FCC juice significantly increased average weight gain (AWG) and average daily gain (ADG) (p < 0.05), whereas carcass traits were not significantly affected (p > 0.05). Most meat quality traits, antioxidant indices, and serum biochemical parameters were unchanged, although serum glucose (GLU) and cholesterol (CHO) decreased in the FCC juice treatment group (p < 0.05). GC × GC-TOF/MS analysis showed that FCC juice altered the volatile profile of fresh sheep meat. Compared with the control group, the FCC juice treatment group showed higher relative contents of aldehydes, ketones, and heterocyclic compounds, but lower contents of hydrocarbons and acids. Seventeen differential volatile compounds were identified using VIP > 1 and FDR-adjusted p < 0.05, with esters representing the major upregulated class. Based on the published odor descriptors of the identified volatile compounds, the FCC juice treatment group showed stronger green and apple-like aroma-associated characteristics. Overall, FCC juice showed a modest positive effect on growth performance and altered the volatile compound profile of fresh sheep meat; however, flavor-related findings should be regarded as preliminary because of the limited slaughter sample size and the absence of direct sensory validation.

Fluorescence resonance energy transfer (FRET)-PCR is widely recognized for its high sensitivity and specificity in pathogen detection. However, there are some gaps in probe design when it is applied for simultaneous detection and differentiation of similar targets. This study aims to investigate the effects of the numbers and position of nucleotide mismatches (NM) in probe on PCR efficiency and melting temperature (T_m). The results indicated that NM at the center reduces amplification efficiency and T_m more significantly than NM at the 5′-terminal or 3′-terminal of the probe.