Analysis of immunoglobulin organization and complexity in mink (Neovison vison).

Mink are susceptible to viruses such as SARS-CoV-2, H1N1 and H9N2, so they are considered a potential animal model for studying human viral infections. Therefore, it is important to study the immune system of mink. Immunoglobulin (Ig) is an important component of humoral immunity and plays an important role in the body's immune defense. In this study, we described the gene loci structure of mink Ig germline by genome comparison, and analysed the mechanism of expression diversity of mink antibody library by 5'RACE and next-generation sequencing (NGS). The results were as follows: the IgH, Igκ and Igλ loci of mink were located on chromosome 13, chromosome 8 and chromosome 3, respectively, and they had 25, 36 and 7 V genes, 3, 5 and 7 J genes and 10 DH genes, respectively. Mink Ig heavy chain preferred the IGHV1, IGHD2 and IGHJ4 subgroups, κ chain mainly use the IGKV1, IGKJ1 and IGHL4 subgroups, and λ chain mainly use the IGLV3 and IGLJ3 subgroups. Linkage diversity analysis revealed that N nucleotide insertion was the main factor affecting the linkage diversity of mink Igs. On the mutation types of mink Ig Somatic Hypermutation (SHM), the high mutation types of heavy chain were mainly G > A, C > T, T > C, A > G, C > A, G > T, A > C, and T > G; the high mutation types of κ chain were G > A and T > C; and the high mutation types of λ chain were G > A and A > G. The objective of this study was to analyse the loci structure and expression diversity of Ig in mink. The results contribute to our comprehension of Ig expression patterns in mink and were valuable for advancing knowledge in mink immunogenetics, exploring the evolution of adaptive immune systems across different species, and conducting comparative genomics research.

Differential analysis of immunoglobulin gene expression pattern in chickens of distinct breeds and developmental periods.

Immunoglobulin is an essential component of the body's defense against pathogens, aiding in the recognition and clearance of foreign antigens. Research concerning immunoglobulin gene and its diversity of expression across different breeds within the same species is relatively scarce. In this study, we employed RACE (Rapid Amplification of cDNA Ends) technology, prepared DNA libraries, performed high-throughput sequencing, and conducted related bioinformatics analysis to analyze the differences in immunoglobulin gene diversity and expression at different periods in Hy-line brown hens, Lueyang black-bone chickens, and Beijing-You chickens. The study found that the composition of chicken immunoglobulin genes is relatively simple, with both the light chain and heavy chain having a functional V gene. Additionally, the mechanisms of immunoglobulin diversity generation tended to be consistent among different breeds and periods of chickens, primarily relying on abundant junctional diversity, somatic hypermutation (SHM), and gene conversion (GCV) to compensate for the limitations of low-level V(D)J recombination. As the age increased, the junctional diversity of IgH and IgL tended to diversify and showed similar expression patterns among different breeds. In the three chicken breeds, the predominant types of mutations observed in IGHV and IGLV SHM were A to G and G to A transitions. Specifically, IGLV exhibited a preference for A to G mutations, whereas IGHV displayed a bias toward G to A mutations. The regions at the junctions between framework regions (FR) and complementarity-determining regions (CDR) and within the CDR regions themselves are typically prone to mutations. The locations of GCV events in IGLV and IGHV do not show significant differences, and replacement segments are concentrated in the central regions of FR1, CDR, and FR2. Importantly, gene conversion events are not random occurrences. Additionally, our investigation revealed that CDRH3 in chickens of diverse breeds and periods the potential for diversification through the incorporation of cysteine. This study demonstrates that the diversity of immunoglobulin expression tends to converge among Hy-line brown hens, Lueyang black-bone chickens, and Beijing-You chickens, indicating that the immunoglobulin gene expression mechanisms in different breeds of chickens do not exhibit significant differences due to selective breeding.

Immunoglobulins play a key role in the organism's defense against pathogens, and their diverse expression allows the body to generate a wide array of antibodies. This diversity serves as a critical safeguard for the immune system against various pathogens. Natural geographical variances and artificial breeding and selection can potentially lead to different immune responses in distinct populations of the same species when confronted with the same pathogen. In this study, we investigated the diversity of immunoglobulin gene expression in the natural state of different chicken breeds (Hy-line brown hens, Lueyang black-bone chickens, and Beijing-You chickens) and at different periods from the perspective of immunoglobulin gene expression mechanism. We analyzed the diversity of immunoglobulin based on the results of high-throughput sequencing by extracting Fabricius bursa RNA, RACE (Rapid Amplification of cDNA Ends) technique, and constructing DNA libraries. Our study reveals that the junctional diversity, somatic hypermutation, CDR3 diversity, and gene conversion expression of immunoglobulins in Hy-line brown hens, Lueyang black-bone chickens, and Beijing-You chickens converge during the same time period. This indicates that the immunoglobulin gene expression mechanisms in different chicken breeds do not exhibit significant variations as a result of selective breeding.

Effect of Five Different Antioxidants on the Effectiveness of Goat Semen Cryopreservation.

The effective combination of semen cryopreservation and artificial insemination has a positive effect on the conservation of germplasm resources, production and breeding, etc. However, during the process of semen cryopreservation, the sperm cells are very susceptible to different degrees of physical, chemical, and oxidative stress damage. Oxidative damage is the most important factor that reduces semen quality, which is affected by factors such as dilution equilibrium, change of osmotic pressure, cold shock, and enzyme action during the freezing-thawing process, which results in the aggregation of a large amount of reactive oxygen species (ROS) in sperm cells and affects the quality of semen after thawing. Therefore, the method of adding antioxidants to semen cryoprotective diluent is usually used to improve the effect of semen cryopreservation. The aim of this experiment was to investigate the effects of adding five antioxidants (GLP, Mito Q, NAC, SLS, and SDS) to semen cryoprotection diluent on the cryopreservation effect of semen from Saanen dairy goats. The optimal preservation concentrations were screened by detecting sperm viability, plasma membrane integrity, antioxidant capacity, and acrosomal enzyme activities after thawing, and the experimental results were as follows: the optimal concentrations of GLP, Mito Q, NAC, SLS, and SDS added to semen cryopreservation diluent at different concentrations were 0.8 mg/mL, 150 nmol/L, 0.6 mg/mL, 0.15 mg/ mL, 0.6 mg/mL, and 0.15 mg/mL. The optimal concentrations of the five antioxidants were added to the diluent and analyzed after 1 week of cryopreservation, and it was found that sperm viability, plasma membrane integrity, and mitochondrial activity were significantly enhanced after thawing compared with the control group (P < 0.05), and their antioxidant capacity was significantly enhanced (P < 0.05). Therefore, the addition of the above five antioxidants to goat sperm cryodilution solution had a better enhancement of sperm cryopreservation. This study provides a useful reference for exploring the improvement of goat semen cryoprotection effect.

[Application of Micro-aerobic Hydrolysis Acidification in the Pretreatment of Petrochemical Wastewater].

Micro-aerobic hydrolysis acidification technology was applied in the reconstruction of ananaerobic hydrolysis acidification tank in a north petrochemical wastewater treatment plant. After put into operation, the monitoring results showed that the average removal rate of COD was 11.7% when influent COD was 490.3-673.2 mg x L(-1), hydraulic retention time (HRT) was 24 and the dissolved oxygen (DO) was 0.2-0.35 mg x L(-1). In addition, the BOD5/COD value was increased by 12.4%, the UV254 removal rate reached 11.2%, and the VFA concentration was increased by 23.0%. The relative molecular weight distribution (MWD) results showed that the small molecule organic matter (< 1 x 10(3)) percentage was increased from 59.5% to 82.1% and the high molecular organic matter ( > 100 x 10(3)) percentage was decreased from 31.8% to 14.0% after micro-aerobic hydrolysis acidification. The aerobic biodegradation batch test showed that the degradation of petrochemical wastewater was significantly improved by the pretreatment of micro-aerobic hydrolysis acidification. The COD of influent can be degraded to 102.2 mg x L(-1) by 48h aerobic treatment while the micro-aerobic hydrolysis acidification effluent COD can be degraded to 71.5 mg x L(-1) on the same condition. The effluent sulfate concentration of micro-aerobic hydrolysis acidification tank [(930.7 ± 60.1) mg x L(-1)] was higher than that of the influent [(854.3 ± 41.5) mg x L(-1)], indicating that sulfate reducing bacteria (SRB) was inhibited. The toxic and malodorous gases generation was reduced with the improvement of environment.