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Bromodomain protein BRD4 binds to acetylated histones to regulate transcription. BRD4 also drives cancer cell proliferation. However, the role of BRD4 in normal cell growth has remained unclear. Here, we investigated this question by using mouse embryonic fibroblasts with conditional Brd4 knockout (KO). We found that Brd4KO cells grow more slowly than wild type cells; they do not complete replication, fail to achieve mitosis, and exhibit extensive DNA damage throughout all cell cycle stages. BRD4 was required for expression of more than 450 cell cycle genes including genes encoding core histones and centromere/kinetochore proteins that are critical for genome replication and chromosomal segregation. Moreover, we show that many genes controlling R-loop formation and DNA damage response (DDR) require BRD4 for expression. Finally, BRD4 constitutively occupied genes controlling R-loop, DDR and cell cycle progression. In summary, BRD4 epigenetically marks above genes and serves as a master regulator of normal cell growth.
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Introduction and Objective. Pets infected with zoonotic pathogens might become a source of infections for their owners, especially those who are immuno-compromised. The aim of this report is to describe a case of chronic, untreatable pneumonia in a domestic ferret. Materials and method. The subject was a 5-year-old female ferret suffering from recurrent pneumonia. Ante-mortally, swabs from the nasal cavity, alveolus and throat were collected from the animal. Post-mortally, lesioned organ fragments were collected. Standard microbiological testing was performed. Additionally, mycobacterial diagnosis including culture and molecular tests was performed. Results. The co-infection of Mycobacterium avium and Klebsiella pneumoniae was microbiologically confirmed. Conclusions. This case demonstrates the need to pay attention to the possibility of zoonotic pathogens in ferrets. Veterinarians diagnosing ferrets are potentially exposed to Mycobacteria spp. infections and other pathogens.
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Coinfecção , Furões , Infecções por Klebsiella , Klebsiella pneumoniae , Mycobacterium avium , Animais , Furões/microbiologia , Feminino , Klebsiella pneumoniae/isolamento & purificação , Coinfecção/veterinária , Coinfecção/microbiologia , Infecções por Klebsiella/veterinária , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/diagnóstico , Mycobacterium avium/isolamento & purificação , Tuberculose/veterinária , Tuberculose/microbiologia , Tuberculose/diagnóstico , Evolução FatalRESUMO
Salmonella diarizonae (IIIb) is frequently isolated from reptiles and less frequently from birds and mammals. However, its isolation from invasive human infections has not been widely reported. Migratory mallard ducks are excellent bioindicators of pathogen presence and pathogen antibiotic resistance (AMR). We present the first isolation from a mallard duck in central Europe of the antibiotic-resistant Salmonella enterica subsp. diarizonae with the unique antigenic pattern 58:r:z53 and report its whole-genome sequencing, serosequencing, and genotyping, which enabled the prediction of its pathogenicity and comparison with phenotypic AMR. The isolated strain was highly similar to S. diarizonae isolated from humans and food. Twenty-four AMR genes were detected, including those encoding aminoglycoside, fluoroquinolone, macrolide, carbapenem, tetracycline, cephalosporin, nitroimidazole, peptide antibiotic, and disinfecting agent/antiseptic resistance. Six Salmonella pathogenicity islands were found (SPI-1, SPI-2, SPI-3, SPI-5, SPI-9, and SPI-13). An iron transport system was detected in SPI-1 centisome C63PI. Plasmid profile analyses showed three to be present. Sequence mutations in the invA and invF genes were noted, which truncated and elongated the proteins, respectively. The strain also harbored genes encoding type-III secretion-system effector proteins and many virulence factors found in S. diarizonae associated with human infections. This study aims to elucidate the AMR and virulence genes in S. enterica subsp. diarizonae that may most seriously threaten human health.
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Patos , Animais , Patos/microbiologia , Humanos , Salmonella/genética , Salmonella/patogenicidade , Salmonella/isolamento & purificação , Salmonella/efeitos dos fármacos , Sequenciamento Completo do Genoma , Ilhas Genômicas/genética , Salmonelose Animal/microbiologia , Antibacterianos/farmacologia , Salmonella enterica/genética , Salmonella enterica/patogenicidade , Salmonella enterica/isolamento & purificação , Salmonella enterica/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Filogenia , Farmacorresistência Bacteriana/genética , Plasmídeos/genéticaRESUMO
Multiple myeloma (MM) is an incurable plasma cell malignancy that exploits transcriptional networks driven by IRF4. We employ a multi-omics approach to discover IRF4 vulnerabilities, integrating functional genomics screening, spatial proteomics, and global chromatin mapping. ARID1A, a member of the SWI/SNF chromatin remodeling complex, is required for IRF4 expression and functionally associates with IRF4 protein on chromatin. Deleting Arid1a in activated murine B cells disrupts IRF4-dependent transcriptional networks and blocks plasma cell differentiation. Targeting SWI/SNF activity leads to rapid loss of IRF4-target gene expression and quenches global amplification of oncogenic gene expression by MYC, resulting in profound toxicity to MM cells. Notably, MM patients with aggressive disease bear the signature of SWI/SNF activity, and SMARCA2/4 inhibitors remain effective in immunomodulatory drug (IMiD)-resistant MM cells. Moreover, combinations of SWI/SNF and MEK inhibitors demonstrate synergistic toxicity to MM cells, providing a promising strategy for relapsed/refractory disease.
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Proteínas de Ligação a DNA , Fatores Reguladores de Interferon , Mieloma Múltiplo , Plasmócitos , Fatores de Transcrição , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/patologia , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Fatores Reguladores de Interferon/metabolismo , Fatores Reguladores de Interferon/genética , Animais , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Humanos , Camundongos , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Plasmócitos/efeitos dos fármacos , Plasmócitos/metabolismo , Plasmócitos/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Linhagem Celular Tumoral , Diferenciação Celular/efeitos dos fármacosRESUMO
The gut and liver are recognized to mutually communicate through the biliary tract, portal vein, and systemic circulation. However, it remains unclear how this gut-liver axis regulates intestinal physiology. Through hepatectomy and transcriptomic and proteomic profiling, we identified pigment epithelium-derived factor (PEDF), a liver-derived soluble Wnt inhibitor, which restrains intestinal stem cell (ISC) hyperproliferation to maintain gut homeostasis by suppressing the Wnt/ß-catenin signaling pathway. Furthermore, we found that microbial danger signals resulting from intestinal inflammation can be sensed by the liver, leading to the repression of PEDF production through peroxisome proliferator-activated receptor-α (PPARα). This repression liberates ISC proliferation to accelerate tissue repair in the gut. Additionally, treating mice with fenofibrate, a clinical PPARα agonist used for hypolipidemia, enhances colitis susceptibility due to PEDF activity. Therefore, we have identified a distinct role for PEDF in calibrating ISC expansion for intestinal homeostasis through reciprocal interactions between the gut and liver.
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Intestinos , Fígado , Animais , Camundongos , Proliferação de Células , Fígado/metabolismo , PPAR alfa/metabolismo , Proteômica , Células-Tronco/metabolismo , Via de Sinalização Wnt , Intestinos/citologia , Intestinos/metabolismoRESUMO
BRD4 binds to acetylated histones to regulate transcription and drive cancer cell proliferation. However, the role of BRD4 in normal cell growth remains to be elucidated. Here we investigated the question by using mouse embryonic fibroblasts with conditional Brd4 knockout (KO). We found that Brd4KO cells grow more slowly than wild type cells: they do not complete replication, fail to achieve mitosis, and exhibit extensive DNA damage throughout all cell cycle stages. BRD4 was required for expression of more than 450 cell cycle genes including genes encoding core histones and centromere/kinetochore proteins that are critical for genome replication and chromosomal segregation. Moreover, we show that many genes controlling R-loop formation and DNA damage response (DDR) require BRD4 for expression. Finally, BRD4 constitutively occupied genes controlling R-loop, DDR and cell cycle progression. We suggest that BRD4 epigenetically marks those genes and serves as a master regulator of normal cell growth.
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In the period 1996-2012, two outbreaks of animal tuberculosis were noted in the population of free-living European bison (Bison bonasus caucasicus) in the Bieszczady Mountains, Southern Poland. As the European bison is an endangered species and particularly susceptible to tuberculosis, not to mention a national icon, the decision was made to test all deceased bison for TB in Poland. The screened bison were obtained by elimination due to poor health or natural death. A total of 159 European bison have been examined over the last 10 years. The individuals came from four regions of Poland (Bialowieza Forest, Bieszczady Mountains, Borecka Forest, Knyszynska Forest), not only from the area where tuberculosis is still endemic. Mycobacterium bovis and Mycobacterium avium spp. hominisuis were identified in two different herds. The isolation of M. bovis from European bison was the first case described in Poland. So far, the only causative agent of tuberculosis identified in European bison in Poland, both in the wild and in captive herds, was Mycobacterium caprae. The isolated M. bovis spoligotype has not previously been registered in international spoligotype databases so far. The obtained results highlight the need to monitor TB in European bison in Poland.
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Food business operators must include the results of shelf life testing in their HACCP plan. Ready-to-eat preservative-free meat products enriched with blood plasma are an unfathomable area of research in food safety. We tested modified atmosphere (80% N2 and 20% CO2) and vacuum packaged RTE preservative-free baked and smoked pork bars with dried blood plasma for Aerobic Plate Count, yeast and mould, lactic acid bacteria, Staphylococcus aureus, Enterobacteriaceae, Escherichia coli, and Campylobacter spp., and the presence of Listeria monocytogenes and Salmonella spp. during storage (temperatures from 4 to 34 °C) up to 35 days after production. The obtained data on the count of individual groups of microorganisms were subjected to analysis of variance (ANOVA) and statistically tested (Student's t-test with the Bonferroni correction); for temperatures at which there were statistically significant differences and high numerical variability, the trend of changes in bacterial counts were visualised using mathematical modelling. The results show that the optimal storage conditions are refrigerated temperatures (up to 8 °C) for two weeks. At higher temperatures, food spoilage occurred due to the growth of aerobic bacteria, lactic acid bacteria, yeast, and mould. The MAP packaging method was more conducive to spoilage of the bars, especially in temperatures over 8 °C.
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Oncogenic RAS mutations are common in multiple myeloma (MM), an incurable malignancy of plasma cells. However, the mechanisms of pathogenic RAS signaling in this disease remain enigmatic and difficult to inhibit therapeutically. We employ an unbiased proteogenomic approach to dissect RAS signaling in MM. We discover that mutant isoforms of RAS organize a signaling complex with the amino acid transporter, SLC3A2, and MTOR on endolysosomes, which directly activates mTORC1 by co-opting amino acid sensing pathways. MM tumors with high expression of mTORC1-dependent genes are more aggressive and enriched in RAS mutations, and we detect interactions between RAS and MTOR in MM patient tumors harboring mutant RAS isoforms. Inhibition of RAS-dependent mTORC1 activity synergizes with MEK and ERK inhibitors to quench pathogenic RAS signaling in MM cells. This study redefines the RAS pathway in MM and provides a mechanistic and rational basis to target this mode of RAS signaling.
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Genes ras , Mieloma Múltiplo , Fatores de Transcrição , Aminoácidos/metabolismo , Genes ras/genética , Genes ras/fisiologia , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Mutação , Isoformas de Proteínas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
How pioneer factors interface with chromatin to promote accessibility for transcription control is poorly understood in vivo. Here, we directly visualize chromatin association by the prototypical GAGA pioneer factor (GAF) in live Drosophila hemocytes. Single-particle tracking reveals that most GAF is chromatin bound, with a stable-binding fraction showing nucleosome-like confinement residing on chromatin for more than 2 min, far longer than the dynamic range of most transcription factors. These kinetic properties require the full complement of GAF's DNA-binding, multimerization and intrinsically disordered domains, and are autonomous from recruited chromatin remodelers NURF and PBAP, whose activities primarily benefit GAF's neighbors such as Heat Shock Factor. Evaluation of GAF kinetics together with its endogenous abundance indicates that, despite on-off dynamics, GAF constitutively and fully occupies major chromatin targets, thereby providing a temporal mechanism that sustains open chromatin for transcriptional responses to homeostatic, environmental and developmental signals.
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Proteínas de Drosophila , Fatores de Transcrição , Animais , Cromatina , Proteínas de Ligação a DNA/metabolismo , Drosophila/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Cinética , Fatores de Transcrição/metabolismoRESUMO
The "One Health" approach increasingly demonstrates the global spread of pathogenic microorganisms and their antimicrobial resistance in the environment, both in animals and humans. Salmonella enterica subsp. diarizonae is nowadays very often isolated from cold-blooded reptiles to a lesser extent from sheep, but unfortunately more and more often from humans. However, there are a few studies describing the isolation of Salmonella enterica subsp. diarizonae from migratory wild birds. The mallard duck (Anas platyrhynchos), a wild animal that traverses the continent of Eurasia, can be an excellent indicator of the spread of intestinal microbes as well as their resistance to antibiotics. This is the first report of the Salmonella enterica subsp. diarizonae detection in Poland in a migrating mallard duck. This research presented the identification difficulties associated with the isolation of Salmonella enterica subsp. diarizonae using three different biochemical tests and advanced serology tests. At the same time, we detected very high antimicrobial resistance in the isolated strain. By using the minimum inhibitory concentration (MIC) method, it was found that the isolated strain of S. enterica subsp. diarizonae has high antibiotic resistance against 14 of the 33 tested antimicrobials agents. The resistance genes that have been identified in S. enterica subsp. diarizonae include aadA, strA/strB, and blaTEM.
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Alaria alata is an emerging parasite that poses a potential risk for those consuming game, pork, snails and frogs. One paratenic host of A. alata that is known to play an important role in its spread through its feeding habitats is the wild boar. However, no statistical analysis of the influence of aquatic environments and carnivores on the occurrence of A. alata in wild boars has yet been performed. The present study combines a small-scale analysis based on hunting districts in the Mazowieckie province with a large-scale analysis based on data for all provinces in Poland. We applied various modeling approaches, including logistic regression and a generalized linear model in order to determine the presence, intensity and prevalence of A. alata. We used the Alaria mesocercariae migration technique (AMT) to estimate the risk of A. alata among wild boar in a given hunting district or province. The small-scale analysis found that mesopredators (red fox (Vulpes vulpes)) and racoon dog (Nyctereutes procyinoides) were likely to influence A. alata infestation of wild boar; however, the effect was weak, probably as a result of the large home range size of these animals. The large-scale analysis found that wetlands influence the prevalence of A. alata in wild boar, with the estimated risk increasing in the north of the country; this finding is consistent with other studies. Our findings indicate that the occurrence of A. alata in wild boar requires analysis on many levels, and environmental factors play a key role in risk assessment.
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Despite the threat posed by tuberculosis (TB) to the protected European bison (Bison bonasus), no validated TB tests exist for this species. This pilot study evaluates two tests based on detecting cellular immunity for this purpose: interferon gamma release assay (IGRA) and tuberculin skin test (TST). Ten animals were subjected to ante-mortem and post-mortem examinations. IGRA was performed using a commercial test, and the comparative TST was performed in the eyelids. The lesions were assessed post-mortem and material was collected for mycobacterial culture. The isolated strains were subjected to genotyping. At post-mortem examination, five out of ten individuals demonstrated both tuberculous lesions and positive culture results (Mycobacterium caprae). Compared to the palpebral TST, the findings of the IGRA are easier to interpret when diagnosing tuberculosis in European bison.
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BACKGROUND: The consumption of raw or undercooked meat, especially pork, and offal containing infective tissue cysts is suspected to be a significant route of infection with Toxoplasma gondii. Although the use of "animal-friendly pig production systems" ensuring direct contact with the natural environment offers ethical benefits, it limits the ability to ensure animal health; it may also increase the probability of infections by pathogens such as T. gondii, and thus their entry into the food chain. This study determines the seroprevalence of T. gondii in pigs from different housing systems and farms with different hygiene standards in Poland, as well as among pigs of different age groups from farms with high hygiene standards. In total 760 pig serum samples were examined for the presence of specific antibodies using the PrioCHECK® Toxoplasma Ab porcine commercial ELISA test (Prionics, Switzerland). RESULTS: Test results with PP ≥ 20% were regarded as positive, as indicated by the manufacturer. Antibodies to T. gondii were found in 193 of 760 (25.4%) tested sera. Regarding different housing systems, antibodies were found in 117 pigs: of these, 52.6% (61/116) were from organic farms, 40.9% (47/115) from farms with low hygiene standards, 5.4% (9/167) from farms with high hygiene standards and 0% (0/40) from a farm with a high level of biosecurity. Regarding age groups, antibodies were found in 76 animals on farms with high hygiene standards: 11.1% (7/63) were pigs younger than 3 months, 0% (0/60) aged 3-4 months, 12.3% (7/57) aged 5-6 months (final fattening stage) and 43.7% (62/142) were sows aged 9 months and older. CONCLUSIONS: Antibodies to T. gondii were most often found in pigs from organic and low-hygiene farms, as well as in pigs aged 9 months and older. Meat derived from seropositive animals can pose a potential source of infection for humans. As maternal antibodies to T. gondii can be present in the blood of piglets aged up to 3-4 months, serological examination is unjustified in piglets up to this age.
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Doenças dos Suínos , Toxoplasma , Toxoplasmose Animal , Animais , Anticorpos Antiprotozoários , Feminino , Habitação , Agricultura Orgânica , Polônia/epidemiologia , Estudos Soroepidemiológicos , Suínos , Doenças dos Suínos/epidemiologia , Toxoplasmose Animal/epidemiologiaRESUMO
High-intensity transcription and replication supercoil DNA to levels that can impede or halt these processes. As a potent transcription amplifier and replication accelerator, the proto-oncogene MYC must manage this interfering torsional stress. By comparing gene expression with the recruitment of topoisomerases and MYC to promoters, we surmised a direct association of MYC with topoisomerase 1 (TOP1) and TOP2 that was confirmed in vitro and in cells. Beyond recruiting topoisomerases, MYC directly stimulates their activities. We identify a MYC-nucleated "topoisome" complex that unites TOP1 and TOP2 and increases their levels and activities at promoters, gene bodies, and enhancers. Whether TOP2A or TOP2B is included in the topoisome is dictated by the presence of MYC versus MYCN, respectively. Thus, in vitro and in cells, MYC assembles tools that simplify DNA topology and promote genome function under high output conditions.
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DNA Topoisomerases Tipo II/metabolismo , Neoplasias/enzimologia , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transcrição Gênica , Animais , Replicação do DNA , DNA Topoisomerases Tipo I/genética , DNA Topoisomerases Tipo I/metabolismo , DNA Topoisomerases Tipo II/genética , DNA de Neoplasias/biossíntese , DNA de Neoplasias/genética , DNA Super-Helicoidal/biossíntese , DNA Super-Helicoidal/genética , Ativação Enzimática , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Humanos , Células K562 , Complexos Multienzimáticos , Neoplasias/genética , Neoplasias/patologia , Proteínas de Ligação a Poli-ADP-Ribose/genética , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/genética , RatosRESUMO
INTRODUCTION AND OBJECTIVE: In recent years, bovine tuberculosis (BTB) has become one of the major health hazards facing the European bison (EB, Bison bonasus), a vulnerable species that requires active protection, including regular and effective health monitoring. Monitoring of zoonotic disease in wildlife is also an important part of public health protection. The aim of the study was to determine whether BTB still influences the EB population in Poland. MATERIAL AND METHODS: During 2017-2019, mandibular, retropharyngeal and mediastinal lymph nodes were collected from 90 EB during post-mortem examination, and then cultivated on Lowenstein-Jensen and Stonebrink media. Isolated strains were subjected to molecular analysis to determine the species, spoligotype and MIRU-VNTR pattern. RESULTS: Lesions were found in lymph nodes originating from eight EB (8.89%). Positive microbiological cultures for mycobacteria were obtained in samples from six (6.67%) EB. The isolated strains were identified as Mycobacterium caprae (material from four EB) and atypical mycobacteria (material from two EB). For M. caprae strains spoligotype M. bovis 4_CA 1600 was identified and the MIRU-VNTR pattern was identified as 345751355413232. CONCLUSIONS: It is recommended that this potentially dangerous disease should be monitored in EB via a comprehensive strategy based on a combination of microbiological and molecular methods. Such monitoring will protect the health of both animals and humans.
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Bison , Mycobacterium bovis , Tuberculose Bovina , Animais , Animais Selvagens , Bovinos , Mycobacterium bovis/genética , Polônia/epidemiologiaRESUMO
Transcription initiation by RNA polymerase II (RNA Pol II) requires preinitiation complex (PIC) assembly at gene promoters. In the dynamic nucleus, where thousands of promoters are broadly distributed in chromatin, it is unclear how multiple individual components converge on any target to establish the PIC. Here we use live-cell, single-molecule tracking in S. cerevisiae to visualize constrained exploration of the nucleoplasm by PIC components and Mediator's key role in guiding this process. On chromatin, TFIID/TATA-binding protein (TBP), Mediator, and RNA Pol II instruct assembly of a short-lived PIC, which occurs infrequently but efficiently within a few seconds on average. Moreover, PIC exclusion by nucleosome encroachment underscores regulated promoter accessibility by chromatin remodeling. Thus, coordinated nuclear exploration and recruitment to accessible targets underlies dynamic PIC establishment in yeast. Our study provides a global spatiotemporal model for transcription initiation in live cells.
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Complexo Mediador/metabolismo , RNA Polimerase II/metabolismo , Iniciação da Transcrição Genética/fisiologia , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/fisiologia , Complexo Mediador/genética , Nucleossomos/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Análise Espaço-Temporal , Proteína de Ligação a TATA-Box/genética , Fator de Transcrição TFIID/genética , Transcrição Gênica/genéticaRESUMO
Distomum musculorum suis (DMS), the mesocercariae of Alaria alata, is typically found accidently during examination of wild boar meat for Trichinella spp. The aim of the study was to compare DMS detection methods. Briefly, 232 wild boar meat samples were tested by mesocercariae migration technique (AMT) as a reference method; of these, 104 were found to be positive. Selected positive samples were tested again with the three other methods: compressorium method (Compressor), digestion with magnetic stirrer (Digestion) and by modified digestion with Pancreatin® bile and pancreatic enzymes (D + P). The results were analyzed by logistic regression, the non-parametric Kruskal-Wallis test and the Mann-Whitney U test. Of the 43 samples found positive by the AMT, 20 were found positive by Digestion and 25 by D + P. The Compressor identified DMS in seven of the 19 tested samples. The Digestion and D + P methods gave similar intensities (P = 0.506), i.e. 1.4 and 1.3 DMS respectively, but the AMT detected seven times higher number of parasites. The probability of detection of DMS in the meat sample by the Digestion or by D + P was higher than 0.5 when at least seven (Digestion) or five (D + P) DMS were present in the sample (AMT). The Compressor was the least sensitive method: at least 14 DMS must be present in the meat sample for detection. AMT should be considered the most accurate method of DMS detection.
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The present study examines the esophageal wall of animals from two distinct families of the Ruminantia: domestic goats and European roe deer. Five fragments were collected from the entire length of the esophageal wall in five goats and four roe deer and subjected to microscopic and morphometric analyses. All layers of the esophageal wall except the tela submucosa were found to be thicker in the goats. In both species, the esophagus was lined by parakeratinized stratified squamous epithelium, and the tela submucosa was deprived of glands along its entire length. However, the structure of the lamina muscularis mucosae was better developed in goats: it was found to be discontinuous in the proximal part, and then became fused in the cervical part, that is around the most proximal quarter of its length. In contrast, in roe deer, the lamina muscularis mucosae began as sparse, thin muscle bundles at the pharyngeal-esophageal junction, which thickened and clustered further down the esophagus, but did not fuse. Our findings regarding the microscopic structure of the ruminant esophagus are not fully consistent with the widely-accepted view and suggest that the histological structure of the esophagus demonstrates interspecies variation within this large suborder. More precisely, species-specific differences can be seen regarding the presence of esophageal glands and parakeratinized epithelium, and in the organization of the lamina muscularis mucosae.