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.

Chlorpyrifos inhibits sperm maturation and induces a decrease in mouse male fertility.

BACKGROUND: Pesticides, especially organophosphorus pesticides such as chlorpyrifos (CPF), play an important role in modern agriculture. Studies have shown that pesticide residues are an important cause of male reproductive injury in mammal. AIM: The aim of this study was to evaluate the reproductive damage caused by CPF in male mice and investigate the underlying mechanisms. METHODS: In vivo, C57BL/6 mice (6-8 weeks old) were treated with CPF for 14, 70, and 80 days by intraperitoneal injection, intragastric administration, and dietary supplementation, respectively. Then, sperm from the cauda epididymidis was cultured in vitro to confirm the deleterious effects of CPF. RESULTS: The in vivo results indicated that, after treatment with CPF by dietary supplementation and intraperitoneal injection, the expression of reproduction-related genes in the mouse testes was altered, although the mice were fertile and the testes presented no morphological abnormalities. Notably, mating experiments revealed that the fertility of male mice was decreased following CPF administration by gavage. Sperm motility within the cauda epididymidis declined significantly after CPF treatment, which was accompanied by a decrease in sperm density, upregulation of relative reactive oxygen species (ROS) levels, and downregulation of glutathione reductase activity. In vitro incubation experiments showed that sperm rapidly lost their capacity for linear movement; the relative ROS levels also increased significantly, while the mitochondrial membrane potential (MMP) showed a significant decrease. However, the integrity of the plasma membrane was not affected by CPF administration. CONCLUSIONS: The above data indicated that exposure to CPF reduces sperm motility by disrupting mitochondrial function and increasing the level of oxidative stress during sperm maturation, thereby reducing the fecundity of male mice.

Half-metallicity and ferromagnetism in penta-AlN2 nanostructure.

We have performed a detailed first-principles study of the penta-AlN2 nanostructure in the Cairo pentagonal tiling geometry, which is dynamically stable due to the absence of imaginary mode in the calculated phonon spectrum. The formation energy and the fragment cohesive energy analyses, the molecular dynamics simulations, and the mechanical property studies also support the structural stability. It could withstand the temperature as high as 1400 K and sustain the strain up to 16.1% against structural collapse. The slightly buckled penta-AlN2 is found to be a ferromagnetic semiconductor. The strain of ~9% could drive the structural transition from the buckled to the planar. Interestingly, the strain of >7% would change the conducting properties to show half-metallic characters. Furthermore, it could be also used to continuously enhance the magnetic coupling strength, rendering penta-AlN2 as a robust ferromagnetic material. These studies shed light on the possibilities in synthesizing penta-AlN2 and present many unique properties, which are worth of further studying on both theory and experiment.

Penta-BxNy sheet: a density functional theory study of two-dimensional material.

By using density functional theory with generalized gradient approximation, we have carried out detailed investigations of two-dimensional BxNy nanomaterials in the Cairo pentagonal tiling geometry fully composed of pentagons (penta-BxNy). Only penta-BN and BN2 planar structures are dynamically stable without imaginary modes in their phonon spectra. Their stabilities have been further evaluated by formation energy analysis, first-principles molecular dynamics simulation, and mechanical stability analysis. Penta-BN2 is superior to penta-BN in structural stability. Its stability analysis against oxidization and functional group adsorption as well as its synthesizing reaction path analysis show possibilities in fabricating penta-BN2 on experiment. Furthermore, the penta-BN2 could be transferred from metallic to semiconducting by ionizing or covalently binding an electron per dinitrogen. Also, it has been found to have superior mechanical properties, such as the negative Poisson's ratio and the comparable stiffness as that of hexagonal h-BN sheet. These studies on the stabilities, electronic properties, and mechanical properties suggest penta-BN2 as an attractive material to call for further studies on both theory and experiment.

[Treatments of second mesiobuccal canals in maxillary permanent molar: a report of 2 cases].

With the increasing maturation of 3D printing technology, as well as its application in various industries, investigation of 3D printing technology into clinic medical education becomes an important task of the current medical education. The teaching content of oromaxillofacial head and neck surgical oncology is complicated and diverse, making lower understanding/memorizing efficiency and insufficient skill training. To overcome the disadvantage of traditional teaching method, it is necessary to introduce 3D printing technique into teaching of oromaxillofacial head and neck surgical oncology, in order to improve the teaching quality and problem solving capabilities, and finally promote cultivation of skilled and innovative talents.