Exploring the potential immunomodulatory effects of gallic acid on milk phagocytes in bovine mastitis caused by Staphylococcus aureus

Bovine mastitis caused by Staphylococcus aureus may exacerbate by resulting in significant economic losses and impacting milk quality. To date, the use of gallic acid, a phenolic compound naturally occurring in various plants, holds promise due to its potent anti-oxidant and anti-inflammatory effects in many pieces of literature, thus, making it a subject of interest in bovine innate immunity research. Here we used gallic acid to assess its potential immunomodulation on milk phagocytes in vitro challenges with mastitis-causing bacteria. Our findings indicated that cells exposed to gallic acid showed no harm to cell viability but might maintain the longevity of cells during the bacterial infection. Gallic acid-treated cells displayed reduced cell migration, phagocytosis, and bacterial killing ability, while showing an increase in ROS production, all of which are undoubtedly linked to the intracellular killing abilities of the cells. Nonetheless, the extracellular structure called neutrophil extracellular traps (NETs) was significantly released after receiving gallic acid, representing extracellular killing. We also reported that gallic acid neutralizes inflammation by regulating specific pro-inflammatory genes (IL1B, IL6, TNF) and ROS-generating genes (CYBA, LAMP1, RAC1), subsequently preventing tissue damage. Regarding apoptosis-related genes and proteins, the increased production of caspase-3 and Bcl-2 family proteins could potentially promote the longevity of cells, implicated in the mechanism of combating bacterial invasion during udder inflammation and infection. The novel role of gallic acid on milk phagocytes highlights its potential immunomodulatory properties and contributes to our understanding of its effects on bacterial-host interactions, and provides valuable molecular insights

Mammalian sperm capacitation: In vivo and in vitro juxtaposition

The development of assisted reproductive technologies (ART) in mammalian species such as in vitro embryo production (IVEP) has the potential to provide great benefits for significant population increase, improve genetic performance and advancement, and reduce transmission of venereal diseases. Correspondingly, in vitro capacitation of sperm is also paramount, related to the ability of sperm to fertilize oocytes, and was created to imitate in vivo conditions in the female reproductive tract. Amid in vitro capacitation developments, studies on how far in vitro capacitation has progressed in mimicking in vivo scenes have not been thoroughly reviewed as a comparative form. Therefore, the present study outlined the series of alterations in mammalian sperm capacitation during their journey in the female reproductive tract by exploring and juxtaposing processes under in vivo and in vitro conditions. Several essential aspects that become gaps between in vivo and in vitro were also identified and elaborated comprehensively in this systematic literature review. We noted that although in vitro capacitation procedures in certain mammalian species have made promising progress and improvements, it is still poorly successful in other species like horses. Our findings further postulated that the occurrence of cryocapacitation, the high ratio of capacitated sperm/oocyte required for successful fertilization, and the incidence of polyspermy cause capacitation under in vitro settings is less efficient and not yet fully comparable to in vivo. This work is therefore proposed several aspects that need to be bettered from in vitro milieu to make it analogous to in vivo environments in modulating sperm capacitation

In Vitro

The in vitro virustatic and virucidal tests of the crude extract of Cynodon dactylon against infection with porcine reproductive and respiratory syndrome virus (PRRSV), a cause of major devastating pig disease, were described. Crude extract of C. dactylon was prepared for cytotoxicity on tissue-culture cells that were used to measure virustatic and virucidal activities against PRRSV. Crude extract of C. dactylon at 0.78 mg/mL showed no cytotoxicity on the cell line, and at that concentration significantly inhibited replication of PRRSV as early as 24 hours post infection (hpi). C. dactylon also inactivated PRRSV as determined by immunoperoxidase monolayer assay (IPMA) compared to the control experiments. In summary, the present study may be among the earliest studies to describe virustatic and virucidal activities of C. dactylon crude extract against PRRSV in vitro. Extracts of C. dactylon may be useful for PRRSV control and prevention on pig farms

Current perspectives on ruminant sperm freezability: Harnessing molecular changes related to semen quality through omics technologies

The recent advances in sperm cryopreservation transcend cryobanking and other assisted reproductive technologies. Since its discovery, cryopreservation has contributed positive impacts on animal breeding as well as in genetic exchange, improvement, and conservation efforts. However, cryoinjury and variabilities in cryopreservation outcomes remain as key challenges to sperm cryobiology. The present work explored the molecular bases for such freezability differences and freezing-thawing injuries in the ruminant sperm. Relevant biomarkers identified in the seminal plasma and the spermatozoa were highlighted, including lipids, proteins, metabolites, transcripts, and genes. Specific molecular mechanisms concerning sperm structures and functions were also examined relative to their association to cryotolerance, and spermiogram or seminogram modifications following cryopreservation procedures. Current conflicts and gaps in the knowledge base on ruminant spermatozoa were also emphasized. Further investigation of these areas using the available breakthrough molecular tools such as omics technologies is therefore proposed to improve, optimize, or even predict the overall quality of frozen-thawed ruminant semen towards reproductive efficiency

Characterisation of <i>Salmonella enterica</i> clones carrying <i>mcr</i>-1 plasmids in meat products and patients in Northern Thailand using long read sequencing

Salmonella spp. is an important foodborne pathogen associated with consumption of contaminated food, especially food of livestock origin. Antimicrobial resistance (AMR) in Salmonella has been reported globally and increasing AMR in food production is a major public health issue worldwide. The objective of this study was to describe the genetic relatedness among Salmonella enterica isolates, which displayed identical DNA fingerprint profiles. Ten S. enterica isolates were selected from meat and human cases with an identical rep-PCR profile of serovars Rissen (n=4), Weltevreden (n=4), and Stanley (n=2). We used long-read whole genome sequencing (WGS) on the MinION sequencing platform to type isolates and investigate in silico the presence of specific AMR genes. Antimicrobial susceptibility testing was tested by disk diffusion and gradient diffusion method to corroborate the AMR phenotype. Multidrug resistance and resistance to more than one antimicrobial agent were observed in eight and nine isolates, respectively. Resistance to colistin with an accompanying mcr-1 gene was observed among the Salmonella isolates. The analysis of core genome and whole genome MLST revealed that the Salmonella from meat and human salmonellosis were genetically related. Hence, it could be concluded that meat is one of the important sources for Salmonella infection in human

Characterisation of <i>Salmonella enterica</i> clones carrying <i>mcr</i>-1 plasmids in meat products and patients in Northern Thailand using long read sequencing

Salmonella spp. is an important foodborne pathogen associated with consumption of contaminated food, especially food of livestock origin. Antimicrobial resistance (AMR) in Salmonella has been reported globally and increasing AMR in food production is a major public health issue worldwide. The objective of this study was to describe the genetic relatedness among Salmonella enterica isolates, which displayed identical DNA fingerprint profiles. Ten S. enterica isolates were selected from meat and human cases with an identical rep-PCR profile of serovars Rissen (n=4), Weltevreden (n=4), and Stanley (n=2). We used long-read whole genome sequencing (WGS) on the MinION sequencing platform to type isolates and investigate in silico the presence of specific AMR genes. Antimicrobial susceptibility testing was tested by disk diffusion and gradient diffusion method to corroborate the AMR phenotype. Multidrug resistance and resistance to more than one antimicrobial agent were observed in eight and nine isolates, respectively. Resistance to colistin with an accompanying mcr-1 gene was observed among the Salmonella isolates. The analysis of core genome and whole genome MLST revealed that the Salmonella from meat and human salmonellosis were genetically related. Hence, it could be concluded that meat is one of the important sources for Salmonella infection in human

Core genome sequence analysis to characterize <i>Salmonella enterica</i> serovar Rissen ST469 from a swine production chain

Salmonella enterica subsp. enterica serotype Rissen is the predominant serotype found in Thai pork production and can be transmitted to humans through contamination of the food chain. This study was conducted to investigate the genetic relationships between serovar Rissen isolates from all levels of the pork production chain and evaluate the ability of the in silico antimicrobial resistance (AMR) genotypes to predict the phenotype of serovar Rissen. A total of 38 serovar Rissen isolates were tested against eight antibiotic agents by a disk diffusion method and the whole genomes of all isolates were sequenced to detect AMR genetic elements using the ResFinder database.A total of 86.84% of the isolates were resistant to tetracycline, followed by ampicillin (78.96%) and sulfonamide-trimethoprim (71.05%). Resistance to more than one antimicrobial agent was observed in 78.95% of the isolates, with the most common pattern showing resistance to ampicillin, chloramphenicol, streptomycin, sulfonamide-trimethoprim, and tetracycline. The results of genotypic AMR indicated that 89.47% of the isolates carried tet(A), 84.22% carried blaTEM-1B, 78.95% carried sul3, and 78.95% carried dfrA12. The genotypic prediction of phenotypic resistance resulted in a mean sensitivity of 97.45% and specificity of 75.48%. Analysis by core genome multilocus sequence typing (cgMLST) demonstrated that the Salmonella isolates from various sources and different locations shared many of the same core genome loci. This implies that serovar Rissen has infected every stage of the pork production process and that contamination can occur in every part of the production chain

Genetic control of chicken heterophil function in advanced intercross lines: associations with novel and with known Salmonella resistance loci and a likely mechanism for cell death in extracellular trap production

Heterophils, the avian polymorphonuclear leukocyte and the counterpart of mammalian neutrophils, generate the primary innate response to pathogens in chickens. Heterophil performance against pathogens is associated with host disease resistance, and heterophil gene expression and function are under genetic control. To characterize the genomic basis of heterophil function, heterophils from F13 advanced intercross chicken lines (broiler × Leghorn and broiler × Fayoumi) were assayed for phagocytosis and killing of Salmonella enteritidis, oxidative burst, and extracellular trap production. A whole-genome association analysis of single nucleotide polymorphisms at 57,636 loci identified genomic locations controlling these functional phenotypes. Genomic analysis revealed a significant association of extracellular trap production with the SAL1 locus and the SLC11A1 gene, which have both been previously associated with resistance to S. enteritidis. Fine mapping supports SIVA1 as a candidate gene controlling SAL1-mediated resistance and indicates that the proposed cell-death mechanism associated with extracellular trap production, ETosis, likely functions through the CD27/Siva-1-mediated apoptotic pathway. The SLC11A1 gene was also associated with phagocytosis of S. enteritidis, suggesting that the Slc11a1 protein may play an additional role in immune response beyond depleting metal ions to inhibit intracellular bacterial growth. A region of chromosome 6 with no characterized genes was also associated with extracellular trap production. Further characterization of these novel genes in chickens and other species is needed to understand their role in polymorphonuclear leukocyte function and host resistance to disease

Effects of genetic background and dietary immunomodulators on chicken heterophil function and <i>Salmonella</i> resistance

Immune responses in poultry can be influenced by genetic background, nutrition, environment and management, or any combination of the above. Chicken heterophils are the first line of defense that can launch a series of intra- and extracellular antimicrobial mechanisms. Salmonella enterica serovar Enteritidis (SE) is a causative agent of a bacterial foodborne illness, commonly occurring after consumption of contaminated eggs and meat. In 2008, SE affected 3 out of 100,000 U.S. inhabitants on average and it is now receiving increased public awareness. The limited scope of current knowledge about basis for the difference in heterophil responses during and after exposure to immunomodulators prompted the study of heterophil defense mechanisms against Salmonella enterica serovar Enteritidis (SE) infection in three genetically distinct chicken lines (Leghorn, broiler and Fayoumi) supplemented with dietary immunomodulators (β-glucan, ascorbic acid and corticosterone). We hypothesize that heterophil function in three genetic chicken lines during exposure to dietary immunomodulators and challenge with SE will be significantly different. To test the hypothesis, we have isolated blood heterophils from three diverse chicken genetic lines; [outbred broiler and two highly inbred layer lines (Leghorn and Fayoumi)] that were fed diet supplemented with immunomodulators (β-glucan, ascorbic acid and cortisol) and challenged with SE. We used heterophil extracellular trap release (HETs, phagocytosis, bacterial killing and oxidative burst to determine heterophil function differences from different treatment groups. The emphasis of this dissertation was on the role of genetic background and dietary immunomodulators on chicken heterophil function in order to prevent and control SE colonization and shedding, using selected breeds of chickens. First, the baseline heterophil function was monitored in vitro using oxidative burst, phagocytosis and bacterial killing to study intracellular killing mechanisms. Additionally, HETs-DNA release has been for the first time described in avian species and used to explore a potential role of extracellular heterophil killing. We compared the responses of different chicken lines with dietary immunomodulatory effects when exposed to SE challenge. In vivo heterophil function and bacterial clearance by bacterial cultures were evaluated in both challenged and non challenged chickens. The responses of chicken heterophils to dietary immunomodulators and SE challenge were significantly influenced by genetic background, and dietary immunomodulators have significant effect on heterophil function in both non-challenged and challenged chickens. Increased SE clearance in challenged birds that were fed with supplemented diet was also observed. This dissertation provides evidence of the significant role of the genetic background of chicken innate immune system and it's responses to dietary immunomodulation and disease challenge. The results of the studies presented in this dissertation support the use of dietary immunomodulators to manipulate heterophil function in chickens from the same genetic background. The modification of the immune system of chickens with targeted genetic selection and diet supplementation in production settings can lead to improved SE (disease) resistance and reduced risk of food borne illnesses.</p