Enhanced biodegradable polyester film degradation in soil by sequential cooperation of yeast-derived esterase and microbial community

The degradation of biodegradable plastics poses a significant environmental challenge and requires effective solutions. In this study, an esterase derived from a phyllosphere yeast Pseudozyma antarctica (PaE) enhanced the degradation and mineralization of poly(butylene succinate-co-adipate) (PBSA) film in soil. PaE was found to substitute for esterases from initial degraders and activate sequential esterase production from soil microbes. The PBSA film pretreated with PaE (PBSA-E) rapidly diminished and was mineralized in soil until day 55 with high CO2 production. Soil with PBSA-E maintained higher esterase activities with enhancement of microbial abundance, whereas soil with inactivated PaE-treated PBSA film (PBSA-inact E) showed gradual degradation and time-lagged esterase activity increases. The fungal genera Arthrobotrys and Tetracladium, as possible contributors to PBSA-film degradation, increased in abundance in soil with PBSA-inact E but were less abundant in soil with PBSA-E. The dominance of the fungal genus Fusarium and the bacterial genera Arthrobacter and Azotobacter in soil with PBSA-E further supported PBSA degradation. Our study highlights the potential of PaE in addressing concerns associated with biodegradable plastic persistence in agricultural and environmental contexts.

Genome-wide detection of changes in allelic frequency in Landrace pigs selected for resistance to mycoplasma pneumonia of swine

Closed-pig line breeding could change the genetic structure at a genome-wide scale because of the selection in a pig breeding population. We investigated the changes in population structure among generations at a genome-wide scale and the selected loci across the genome by comparing the observed and expected allele frequency changes in mycoplasma pneumonia of swine (MPS)-selected pigs. Eight hundred and seventy-four Landrace pigs, selected for MPS resistance without reducing average daily gain over five generations, had 37,299 single nucleotide polymorphisms (SNPs) and were used for genomic analyses. Regarding population structure, individuals in the first generation were the most widely distributed and then converged into a specific group, as they were selected over five generations. For allele frequency changes, 96 and 14 SNPs had higher allele frequency changes than the 99.9% and 99.99% thresholds of the expected changes, respectively. These SNPs were evenly spread across the genome, and a few of these selected regions overlapped with previously detected quantitative trait loci for MPS and immune-related traits. Our results indicated that the considerable changes in allele frequency were identified in many regions across the genome by closed-pig line breeding based on estimated breeding value.

Establishment and characterization of the immortalized porcine lung-derived mononuclear phagocyte cell line

Mononuclear phagocytes (MNP), including monocytes, dendritic cells (DC), and macrophages, play critical roles in innate immunity. MNP are abundant in the lungs and contribute to host defense against airborne agents and pulmonary immune homeostasis. In this study, we isolated porcine lung-derived MNP (PLuM) from primary cultures of parenchymal lung cells and then immortalized them by transferring the SV40 large T antigen gene and porcine telomerase reverse transcriptase gene using lentiviral vectors. The established cell line, immortalized PLuM (IPLuM), expressed DC/macrophage markers; i.e., CD163, CD172a, and major histocompatibility complex class II, whereas they did not express a porcine monocyte-specific marker, CD52. The expression patterns of these cell surface markers indicate that IPLuM originate from the DC/macrophage lineage rather than the monocyte lineage. The bacterial cell wall components muramyl dipeptide and lipopolysaccharide induced the production of the interleukin-1 family of pro-inflammatory cytokines in IPLuM. Phagocytotic activity was also detected by time-lapse fluorescence imaging of live cells when IPLuM were cultured in the presence of pHrodo dye-conjugated E. coli BioParticles. It is worth noting that IPLuM are susceptible to African swine fever virus infection and support the virus' efficient replication in vitro. Taken together, the IPLuM cell line may be a useful model for investigating host-agent interactions in the respiratory microenvironments of the porcine lung.

Polymorphisms in Pattern Recognition Receptor Genes Are Associated with Respiratory Disease Severity in Pig Farms

Reduced productivity caused by infections, particularly respiratory diseases, is a serious problem in pig farming. We have previously reported polymorphisms in porcine pattern recognition receptor genes affecting molecular functions and demonstrated that the 2197A/C polymorphism in the nucleotide-binding oligomerization domain containing 2 (NOD2) gene influences porcine circovirus 2-induced mortality. Here, we investigated how these polymorphisms affect respiratory disease-induced lesions, using samples from a slaughterhouse dealing with pigs from two farms. Lung lesions were evaluated using two scoring systems, Goodwin (GW) and slaughterhouse pleuritis evaluation system (SPES), to determine the influence of Mycoplasma hyopneumoniae (Mhp) and Actinobacillus pleuropneumoniae (App), respectively. SPES scores were significantly higher when the 1205T allele of Toll-like receptor 5 (TLR5-1205T), rather than TLR5-1205C, was present. On the farm with more severe Mhp invasion, lower GW lesion scores were significantly associated with the presence of the NOD-like receptor family pyrin domain containing 3 (NLRP3)-2906G allele; where App invasion was worse, lower SPES scores were significantly associated with the presence of the NOD2-2197C allele. Combinations of polymorphisms in pattern recognition receptor genes can therefore be utilized for breeding for resistance against respiratory diseases in pigs. DNA markers of these polymorphisms can thus be used to improve productivity by reducing respiratory diseases due to bacterial pathogens in pig livestock.

Isolation and immortalization of macrophages derived from fetal porcine small intestine and their susceptibility to porcine viral pathogen infections

Macrophages are a heterogeneous population of cells that are present in all vertebrate tissues. They play a key role in the innate immune system, and thus, in vitro cultures of macrophages provide a valuable model for exploring their tissue-specific functions and interactions with pathogens. Porcine macrophage cultures are often used for the identification and characterization of porcine viral pathogens. Recently, we have developed a simple and efficient method for isolating primary macrophages from the kidneys and livers of swine. Here, we applied this protocol to fetal porcine intestinal tissues and demonstrated that porcine intestinal macrophages (PIM) can be isolated from mixed primary cultures of porcine small intestine-derived cells. Since the proliferative capacity of primary PIM is limited, we attempted to immortalize them by transferring the SV40 large T antigen and porcine telomerase reverse transcriptase genes using lentiviral vectors. Consequently, immortalized PIM (IPIM) were successfully generated and confirmed to retain various features of primary PIM. We further revealed that IPIM are susceptible to infection by the African swine fever virus and the porcine reproductive and respiratory syndrome virus and support their replication. These findings suggest that the IPIM cell line is a useful tool for developing in vitro models that mimic the intestinal mucosal microenvironments of swine, and for studying the interactions between porcine pathogens and host immune cells.

Uracil-auxotrophic marker recycling system for multiple gene disruption in Pseudozyma antarctica

The basidiomycetous yeast Pseudozyma antarctica, which has multiple auxotrophic markers, was constructed, without inserting a foreign gene, as the host strain for the introduction of multiple useful genes. P. antarctica was more resistant to ultraviolet (UV) irradiation than the model yeast Saccharomyces cerevisiae, and a Paura3 mutant (C867T) was obtained after 3 min of UV exposure. A uracil-auxotrophic marker (URA3) recycling system developed in ascomycetous yeasts and fungi was applied to the P. antarctica Paura3 strain. The PaLYS12 and PaADE2 loci were disrupted via site-directed homologous recombination of PaURA3 (pop-in), followed by the removal of PaURA3 (pop-out). In the obtained double auxotrophic strain (Palys12Δ, Paura3), PaADE2 was further disrupted, and PaURA3 was removed to obtain the triple auxotrophic strain PGB800 (Paura3, Palys12Δ, Paade2Δ). The whole-genome sequence of the PGB800 strain did not contain foreign genes used for genetic manipulation and disrupted PaADE2 and PaLYS12 and removed PaURA3, as planned.

NOD2 Genotypes Affect the Symptoms and Mortality in the Porcine Circovirus 2-Spreading Pig Population

The nucleotide oligomerization domain (NOD)-like receptor 2 (NOD2) is an intracellular pattern recognition receptor that detects components of peptidoglycans from bacterial cell walls. NOD2 regulates bowel microorganisms, provides resistance against infections such as diarrhea, and reduces the risk of inflammatory bowel diseases in humans and mice. We previously demonstrated that a specific porcine NOD2 polymorphism (NOD2-2197A > C) augments the recognition of peptidoglycan components. In this study, the relationships between porcine NOD2-2197A/C genotypes affecting molecular functions and symptoms in a porcine circovirus 2b (PCV2b)-spreading Duroc pig population were investigated. The NOD2 allele (NOD2-2197A) with reduced recognition of the peptidoglycan components augmented the mortality of pigs at the growing stage in the PCV2b-spreading population. Comparison of NOD2 allele frequencies in the piglets before and after invasion of PCV2b indicated that the ratio of NOD2-2197A decreased in the population after the PCV2b epidemic. This data indicated that functional differences caused by NOD2-2197 polymorphisms have a marked impact on pig health and livestock productivity. We suggest that NOD2-2197CC is a PCV2 disease resistant polymorphism, which is useful for selective breeding by reducing mortality and increasing productivity.

Genome-wide association studies for production, respiratory disease, and immune-related traits in Landrace pigs

Identification of a quantitative trait locus (QTL) related to a chronic respiratory disease such as Mycoplasmal pneumonia of swine (MPS) and immune-related traits is important for the genetic improvement of disease resistance in pigs. The objective of this study was to detect a novel QTL for a total of 22 production, respiratory disease, and immune-related traits in Landrace pigs. A total of 874 Landrace purebred pigs, which were selected based on MPS resistance, were genotyped using the Illumina PorcineSNP60 BeadChip. We performed single nucleotide polymorphism (SNP)-based and haplotype-based genome-wide association studies (GWAS) to detect a novel QTL and to evaluate the possibility of a pleiotropic QTL for these traits. SNP-based GWAS detected a total of six significant regions in backfat thickness, ratio of granular leucocytes to lymphatic cells, plasma concentration of cortisol at different ages, and complement alternative pathway activity in serum. The significant region detected by haplotype-based GWAS was overlapped across the region detected by SNP-based GWAS. Most of these detected QTL regions were novel regions with some candidate genes located in them. With regard to a pleiotropic QTL among traits, only three of these detected QTL regions overlapped among traits, and many detected regions independently affected the traits.

A specific promoter-type in ribonuclease L gene is associated with phagocytic activity in pigs

We have previously generated Large White pigs with high immune competence using a selection strategy based on phagocytic activity (PA), capacity of alternative complement pathway, and antibody response after vaccination against swine erysipelas. In this study, to identify the genetic changes caused by the immune selection pressure, we compared gene expression and polymorphisms in the promoter region between pigs subjected to the immune selection (immune-selected pigs) and those that were not (non-selected pigs). After lipid A stimulation, using a microarray analysis, 37 genes related to immune function and transcription factor activity showed a greater than three-fold difference in expression between macrophages derived from immune-selected and non-selected pigs. We further performed a polymorphic analysis of the promoter region of the differentially expressed genes, and elucidated the predominant promoter-types in the immune-selected and non-selected pigs, respectively, in the genes encoding ribonuclease L (RNASEL), sterile α motif and histidine-aspartate domain containing deoxynucleoside triphosphate triphosphohydrolase 1, signal transducer and activator of transcription 3, and tripartite motif containing 21. Analysis of the association between these promoter genotypes and the immune phenotypes revealed that the immune-selected promoter-type in RNASEL was associated with increased PA and was inherited recessively. Considering that RNASEL has been reported to be involved in antimicrobial immune response of mice, it may be possible to enhance the PA of macrophages and improve disease resistance in pig populations using RNASEL promoter-type as a DNA marker for selection.

Ligilactobacillus salivarius Strains Isolated From the Porcine Gut Modulate Innate Immune Responses in Epithelial Cells and Improve Protection Against Intestinal Viral-Bacterial Superinfection

Previously, we constructed a library of Ligilactobacillus salivarius strains from the intestine of wakame-fed pigs and reported a strain-dependent capacity to modulate IFN-β expression in porcine intestinal epithelial (PIE) cells. In this work, we further characterized the immunomodulatory activities of L. salivarius strains from wakame-fed pigs by evaluating their ability to modulate TLR3- and TLR4-mediated innate immune responses in PIE cells. Two strains with a remarkable immunomodulatory potential were selected: L. salivarius FFIG35 and FFIG58. Both strains improved IFN-β, IFN-λ and antiviral factors expression in PIE cells after TLR3 activation, which correlated with an enhanced resistance to rotavirus infection. Moreover, a model of enterotoxigenic E. coli (ETEC)/rotavirus superinfection in PIE cells was developed. Cells were more susceptible to rotavirus infection when the challenge occurred in conjunction with ETEC compared to the virus alone. However, L. salivarius FFIG35 and FFIG58 maintained their ability to enhance IFN-β, IFN-λ and antiviral factors expression in PIE cells, and to reduce rotavirus replication in the context of superinfection. We also demonstrated that FFIG35 and FFIG58 strains regulated the immune response of PIE cells to rotavirus challenge or ETEC/rotavirus superinfection through the modulation of negative regulators of the TLR signaling pathway. In vivo studies performed in mice models confirmed the ability of L. salivarius FFIG58 to beneficially modulate the innate immune response and protect against ETEC infection. The results of this work contribute to the understanding of beneficial lactobacilli interactions with epithelial cells and allow us to hypothesize that the FFIG35 or FFIG58 strains could be used for the development of highly efficient functional feed to improve immune health status and reduce the severity of intestinal infections and superinfections in weaned piglets.

Dexamethasone enhances CD163 expression in porcine IPKM immortalized macrophages

In our previous study, we established a unique porcine macrophage cell line, immortalized porcine kidney-derived macrophages (IPKM). The purpose of the present study was to further elucidate the characteristics of IPKM. CD163 is a scavenger receptor for the hemoglobin-haptoglobin complex and is used as a phenotypic marker of anti-inflammatory M2 macrophages. The expression of CD163 is enhanced by dexamethasone (DEX), a potent steroidal anti-inflammatory drug, in human and rodent macrophages in vitro. Therefore, we investigated the effects of DEX on CD163 expression in porcine IPKM. Treatment with DEX markedly enhanced CD163 expression in the IPKM. In addition, we found that SB203580, a selective inhibitor of p38 mitogen-activated protein kinase (MAPK), blocked the effects of DEX, suggesting that the p38 MAPK signaling pathway is involved in the regulation of the DEX-induced enhancement of CD163 expression. Since CD163 is considered to be a putative receptor for the porcine reproductive and respiratory syndrome virus (PRRSV), the effects of DEX on the infection of IPKM by PRRSV were evaluated. Although the IPKM were susceptible to infection by the Fostera PRRSV vaccine strain, DEX treatment did not affect the propagation of the virus in the IPKM. This suggests that the DEX-induced enhancement of CD163 expression alone is not sufficient to facilitate the infection of IPKM by PRRSV.

Susceptibility of immortalized porcine kidney macrophages to porcine reproductive and respiratory syndrome virus-2 infection

Porcine reproductive and respiratory syndrome virus (PRRSV) displays restricted tropism to porcine alveolar macrophages in nature. Meanwhile, non-porcine cell lines derived from African green monkey kidney cell lines are permissive to PRRSV, resulting in their widespread use in PRRSV research. Furthermore, genetically modified cell lines expressing receptors targeted by PRRSV have been established. We previously established porcine immortalized kidney-derived macrophages (IPKMs) that maintained typical macrophage function. In the present study, we demonstrated the advantages of IPKMs for PRRSV research. IPKMs expressed receptors for PRRSV such as CD163 and CD169. The efficiency of virus isolation from field biological samples was higher for IPKMs than for MARC-145 cells. Five different clusters of North American type PRRSV were propagated in IPKMs. Four field strains continuously produced progeny viruses during 10 continuous passages. The efficiency of virus isolation from field biological samples and continuous progeny virus production in the sequential passages using IPKMs indicated that these cells are good vessels for PRRSV research.

Porcine CLEC12B is expressed on alveolar macrophages and blood dendritic cells

CLEC12B is a C-type lectin-like receptor expressed on myeloid cells. In this study, we have characterized the porcine homologue of CLEC12B (poCLEC12B). To this end, we have generated constructs encoding a c-myc tagged version of the whole receptor, or its ectodomain fused to the Fc portion of human IgG1, from a cDNA clone obtained from an alveolar macrophage library, and raised monoclonal antibodies (mAb) against this molecule. Using these mAbs, poCLEC12B was found to be expressed on alveolar macrophages and, at lower levels, on blood conventional type 1 dendritic cells (cDC1) and plasmacytoid DCs. No binding was detected on monocytes, monocyte-derived macrophages or monocyte-derived DCs. Engagement of CLEC12B on alveolar macrophages with mAbs had no apparent effect on cytokine production (TNF-α, IL-8) induced by LPS. These results provide the basis for future investigations aimed to assess the role of poCLEC12B in different microbial infections and to evaluate its potential in vaccination strategies targeting DCs.

Characterization of the Porcine CLEC12A and Analysis of Its Expression on Blood Dendritic Cell Subsets

CLEC12A has been proposed as a suitable target for delivering antigen to dendritic cells (DCs) to enhance vaccine efficacy both in human and mouse. In this study, we have characterized the porcine homolog of CLEC12A (poCLEC12A). Using new monoclonal antibodies (mAb), raised against its ectodomain, poCLEC12A was found to be expressed on alveolar macrophages, blood conventional type 1 and type 2 DCs and plasmacytoid DCs, but not on monocytes, T cells, B cells or NK cells, in contrast to its human and murine homologs. Western blot analysis showed that in alveolar macrophages this receptor is expressed both as a monomer and a dimer. After binding to DCs, anti- poCLEC12A mAb was efficiently internalized. No significant changes were observed in TNFα or IFNα secretion by plasmacytoid DCs stimulated with either CpGs (ODN2216) or polyinosinic-polycytidylic acid (poly I:C), upon incubation with mAb. These results provide the basis for future investigations aimed to assess the ability of anti-poCLEC12A mAbs to improve vaccine efficacy by targeting antigen to DCs.

Full-scale simultaneous partial nitrification, anammox, and denitrification process for treating swine wastewater

A full-scale swine-wastewater activated sludge treatment plant that contains naturally enriched anammox biofilms was investigated for 2 years. Red biofilm in this system included Planctomycetes at a maximum of 62.5% of the total bacteria diversity, including Candidatus Jettenia and Candidatus Brocadia. The plant was operated with an influent containing 1,104 ± 513 mg/L biochemical oxygen demand (BOD) and 629 ± 198 mg/L total nitrogen (TN) (BOD/N of 1.78 ± 0.58) at a volumetric BOD loading rate of 0.32 ± 0.12 kg/m³/d. Notwithstanding drastically varying influent concentrations, BOD removal efficiency was stable at 95 ± 4%. However, TN removal fluctuated at 75 ± 14%. Dissolved oxygen (DO) concentrations in the aeration tank were 0.06-2.0 mg/L. DO concentration greatly affected nitrogen removal, e.g. when DO was lower than 0.3 mg/L, total inorganic nitrogen removal was 61 ± 14% (≤20 °C), 78 ± 16% (20-30 °C), and 75 ± 12% (≥30 °C), whereas at higher DO concentrations, removal rates were 47 ± 13%, 55 ± 16%, and 68%, respectively. As BOD concentration in the influent was limited compared to nitrogen concentration, nitrogen was likely removed by simultaneous nitrification, anammox, and denitrification (SNAD) under microaerobic conditions. Maintaining low DO concentrations would therefore be a simple method to improve nitrogen removal during SNAD processes for swine-wastewater treatment with fluctuating influent.

Effects of thiosulfate addition on ammonia and nitrogen removal in biofilters packed with Oyaishi (pumice tuff)

Ammonia removal is achieved partly by absorption and nitrification in biofilters, resulting in the accumulation of nitrogen and the necessity of treating the effluent water. We investigated the effects of thiosulfate addition to a biofilter containing pumice tuff for ammonia and nitrogen removal in a laboratory-scale experiment. The addition of thiosulfate to the circulating water led to a decreased nitrate and nitrite along with an increase of sulfate. The inorganic nitrogen in the circulating water decreased by up to 44% with thiosulfate addition compared to without thiosulfate. Batch experiments revealed that denitrification activity decreased exponentially along with increases in dissolved oxygen; however, approximately 30% of denitrification activity was maintained at dissolved oxygen concentration of 3.3 mg/L. Metabarcoding of 16S rRNA genes indicated that the genus Thiobacillus had a relative abundance of 0.002%-0.016% of total bacteria in the biofilter packing material. The circulating water pH was decreased below 5 with sulfur oxidation, and ammonium was accumulated without pH control resulting in a decrease in the relative abundance of the family Nitrosomonadaceae. Its relative abundance increased with control of pH to near neutral, indicating that ammonia-oxidizing activity could be maintained by adjusting pH. Thiosulfate addition could stimulate nitrogen removal by sulfur-dependent denitrification in biofiltration systems.

Analysis of the expression of porcine CD200R1 and CD200R1L by using newly developed monoclonal antibodies

CD200R1 and CD200R1-like are paired receptors which modulate activation of immune cells. Here, we describe the characterisation of their porcine homologues. Analysis of database porcine sequences shows an exceptionally high homology between the extracellular Ig-like domains of these receptors, being the rest more dissimilar. We have obtained two mAbs, PCT1 and PCT3, against a CD200R1-Fc recombinant protein, that bind on CHO cells expressing GFP-tagged CD200R1. The specificity of these mAbs was analysed on CD200R1 L, and also on a CD200R1 splicing variant that lacks the V-type Ig domain. PCT1 bound to both CD200R1 and CD200R1L, but not to the splicing variant, what suggests that recognises an epitope in the V-type Ig domain. PCT3 reacted with both CD200R1 variants, but not CD200R1L, probably binding to an epitope in the N-terminal sequence of CD200R1. Analysis of porcine cells with these mAbs showed expression of CD200R1/CD200R1L on B cells, monocytes and alveolar macrophages.

In vivo effect of a TLR5 SNP (C1205T) on Salmonella enterica serovar Typhimurium infection in weaned, specific pathogen-free Landrace piglets

Toll-like receptor 5 is a pattern-recognition receptor for bacterial flagellin. We previously reported that a single nucleotide polymorphism (SNP) of swine TLR5, C1205T, impairs recognition of Salmonella typhimurium (ST) flagellin and ethanol-killed Salmonella Choleraesuis (SC). In the present study, weaned, specific pathogen-free (SPF) Landrace piglets with CC, CT or TT genotypes were orally infected with ST (L-3569 strain) to determine the effect of this specific SNP on ST infection in vivo. Eighteen ST-infected piglets (six each with CC, CT, or TT) exhibited fever and diarrhea for 1 week after infection. TT piglets had the longest duration of fever. TT piglets had the greatest mean diarrhea score during the experimental period, followed by CT and CC piglets. Fecal ST shedding was greater in CT and TT pigs than CC pigs from 2 days after infection. Serum haptoglobin concentration increased in ST-infected piglets and to greater extents in CT and TT pigs than CC pigs. Daily weight gain was lower in infected pigs, particularly TT piglets, than control pigs. To the best of our knowledge, this study is the first to demonstrate that impairment of TLR recognition affects pig susceptibility to disease in vivo. Thus, piglets with the T allele of swine TLR5 (C1205T) exhibit impaired resistance to ST infection. Furthermore, elimination of the T allele of this SNP from Landrace pigs would lead to enhancement of their resistance to ST infection.

Differences in gene expression profiles for subcutaneous adipose, liver, and skeletal muscle tissues between Meishan and Landrace pigs with different backfat thicknesses

Backfat thickness is one of the most important traits of commercially raised pigs. Meishan pigs are renowned for having thicker backfat than Landrace pigs. To examine the genetic factors responsible for the differences, we first produced female crossbred pig lines by mating Landrace (L) × Large White (W) × Duroc (D) females (LWD) with Landrace (L) or Meishan (M) boars (i.e., LWD × L = LWDL for Landrace offspring and LWD × M = LWDM for the Meishan offspring). We confirmed that LWDM pigs indeed had a thicker backfat than LWDL pigs. Next, we performed gene expression microarray analysis in both genetic lines to examine differentially expressed genes (DEGs) in energy metabolism-related tissues, subcutaneous adipose (fat), liver, and longissimus dorsi muscle tissues. We analyzed the annotation of DEGs (2-fold cutoff) to functionally categorize them by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. The number of DEGs in muscle tissues of both lines was much less than that in fat and liver tissues, indicating that DEGs in muscle tissues may not contribute much to differences in backfat thickness. In contrast, several genes related to muscle (in fat tissue) and lipid metabolism (in liver tissue) were more upregulated in LWDM pigs than LWDL pigs, indicating that those DEGs might be responsible for differences in backfat thickness. The different genome-wide gene expression profiles in the fat, liver, and muscle tissues between genetic lines can provide useful information for pig breeders.

Distribution of the CD4 Alleles in Sus scrofa Demonstrates the Genetic Profiles of Western Breeds and Miniature Pigs

Widely used antipig CD4 monoclonal antibodies (mAbs) fail to recognize CD4 alleles characteristic of miniature pig lines such as the National Institutes of Health (NIH) miniature pigs and microminipigs. We surveyed polymorphisms in the coding sequence of the porcine CD4 gene among Western and Oriental pig breeds and Japanese wild boars and investigated their distribution. Of the 13 alleles that we identified among the 47 animals, 2 in group I and 3 in group II were found exclusively in Western breed pigs. Group IV alleles, which included mAb-nonbinding alleles, were found frequently in Oriental breed pigs, suggesting that the mAb-nonbinding allele arose from the gene pool of Oriental pigs. Group IV alleles were also found in Duroc and Large White pigs, suggesting genetic inflow from Oriental pig breeds into Western breeds. Comparison of the CD4 sequences of species in Cetartiodactyla suggested that the group IV alleles in Sus scrofa occurred before the divergence of this species from the other artiodactyls. The different antibody specificities of the various CD4 alleles may facilitate the discrimination of T-cell populations in transplantation studies using miniature pigs. The significance of the preservation of CD4 polymorphisms to immune function in pigs warrants further investigation.

Immortalization and Characterization of Porcine Macrophages That Had Been Transduced with Lentiviral Vectors Encoding the SV40 Large T Antigen and Porcine Telomerase Reverse Transcriptase

The domestic pig is an important agricultural animal, and thus, infectious diseases that affect pigs can cause severe economic losses in the global swine industry. Various porcine pathogens target macrophages, which are classical innate immune cells. Although macrophages basically protect the host from pathogens, they also seem to contribute to infectious processes. Therefore, cultured macrophages can be used to develop in vitro models for studying not only genes associated with porcine innate immunity but also the infectious processes of porcine pathogens. However, the availability of porcine macrophage cell lines is limited. In this study, we describe a novel immortalized porcine kidney-derived macrophage (IPKM) cell line, which was generated by transferring the SV40 large T antigen (SV40LT) and porcine telomerase reverse transcriptase (pTERT) genes into primary porcine kidney-derived macrophages using lentiviral vectors. The IPKM displayed a typical macrophage morphology and was routinely passaged (doubling time: about 4 days). These cells were immunostained for macrophage markers. In addition, they exhibited substantial phagocytosis of polystyrene microbeads and released inflammatory cytokines upon lipopolysaccharide (LPS) stimulation. Furthermore, the maturation and secretion of interleukin-1β were observed after nigericin-induced inflammasome activation in LPS-primed IPKM. These findings suggest that IPKM exhibit the typical inflammatory characteristics of macrophages. By transferring the SV40LT and pTERT genes using lentiviral vectors, we also successfully immortalized macrophages derived from the peripheral blood of a low-density lipoprotein receptor-deficient pig. These results suggest that the co-expression of SV40LT and pTERT is an effective way of immortalizing porcine macrophages.

Genomic sequence and virulence evaluation of MN184A-like porcine reproductive and respiratory syndrome virus in Japan

In this study, a porcine reproductive and respiratory syndrome virus (PRRSV) that was isolated from a 9-week-old diseased pig on a farm in Japan with a high mortality rate during 2007-2008 was characterized. This unique isolate, designated as Jpn5-37, did not have a high nucleotide identity in open reading frame 5 against any Japanese isolates. Among all available type 2 PRRSV complete genome sequences, Jpn5-37 shared the highest nucleotide identity (93.6%) with virulent strain MN184A. The genomic characteristics of Jpn5-37 were highly conserved with respect to the virulent MN184A, including a continuous eight amino acid deletion in the nonstructural protein 2 region. Moreover, virus distribution, viremia and the gross and microscopic characteristics of lesions were investigated in pigs 10 days post-inoculation to elucidate the pathogenicity of the isolate. Intranasal inoculation was found to rapidly result in viremia and dissemination of the Jpn5-37 isolate to several tissues in a similar manner to EDRD1; however, the amounts of Jpn5-37 RNA in serum were significantly greater. Similarly, the quantities of Jpn5-37 viral RNA in all organs tested tended to be higher than with EDRD1 infection. Mean rectal temperatures were significantly higher in the Jpn5-37-inoculated than in the control group at 4 and 6 days post infection (dpi) and in the EDRD1-inoculated group at 6 and 8 dpi. These results suggest that the Jpn5-37 strain replicates and is more efficiently distributed to the organs than is EDRD1 under the same conditions.

Anammox biofilm in activated sludge swine wastewater treatment plants

We investigated anammox with a focus on biofilm in 10 wastewater treatment plants (WWTPs) that use activated sludge treatment of swine wastewater. In three plants, we found red biofilms in aeration tanks or final sedimentation tanks. The biofilm had higher anammox 16S rRNA gene copy numbers (up to 1.35 × 10¹² copies/g-VSS) and higher anammox activity (up to 295 μmoL/g-ignition loss/h) than suspended solids in the same tank. Pyrosequencing analysis revealed that Planctomycetes accounted for up to 17.7% of total reads in the biofilm. Most of them were related to Candidatus Brocadia or Ca. Jettenia. The highest copy number and the highest proportion of Planctomycetes were comparable to those of enriched anammox sludge. Thus, swine WWTPs that use activated sludge treatment can fortuitously acquire anammox biofilm. Thus, concentrated anammox can be detected by focusing on red biofilm.