RESUMO
ABSTRACT: Pork head meat may harbor Salmonella and contaminate other carcass by-products during harvest and fabrication. A large pork processing plant in the United States was sampled bimonthly for 11 months to determine the concentration, prevalence, seasonality, serotype diversity, and antimicrobial susceptibility of Salmonella enterica isolated from cheek meat and head trim of swine carcasses. Each collection consisted of 25 samples on two consecutive days in the morning and afternoon shifts, for a total of 100 cheek meat and 100 head trim samples each month. Tissues were cultured for Salmonella by using restrictive media and enrichment techniques, and a subset of isolates was serotyped, analyzed for antimicrobial susceptibility, and genome sequenced. Salmonella postenrichment prevalence did not differ (P = 0.20) between cheek meat (63%) and head trim (66%). Postenrichment prevalence differed (P < 0.05) by month (January, 94%; March, 80%; May, 54%; July, 59%; September, 47%; and November, 55%) and by processing shift (morning, 68%; afternoon, 62%). The subset (n = 618) of isolates selected for serotyping yielded 21 distinct serotypes: Typhimurium (49%), Infantis (10%), Heidelberg (8%), I 4,[5],12:i:- (8%), and 17 other types (≤5%). In total, 407 multidrug-resistant (MDR; resistance to three or more antibiotic classes) isolates were identified. There were 120 isolates that exhibited the penta-resistant ACSSuT phenotype. In addition, 113 isolates exhibited decreased susceptibility to ciprofloxacin (MIC ≥ 0.12 µg/mL). Resistance genes blaCARB, blaSHV, blaTEM, aac(6')-Ib-cr,qnrB, sul2, and dfrA were expressed in numerous MDR Salmonella isolates. The data herein suggest that pork products from the head, compared with data reported for carcasses, may have a relatively high prevalence of Salmonella with diverse serotypes and MDR.
Assuntos
Carne de Porco , Carne Vermelha , Salmonella enterica , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Farmacorresistência Bacteriana Múltipla , Carne , Testes de Sensibilidade Microbiana , Prevalência , Salmonella , Sorotipagem , Suínos , Estados UnidosRESUMO
ABSTRACT: A series of proof-of-concept studies were developed to determine whether a commercial bacteriophage cocktail could be utilized for the mitigation of Salmonella in bovine peripheral lymph nodes (LNs). The first objective sought to determine whether exogenous phage could be isolated from the LNs following administration. If isolation were successful, the second objective was to determine whether the phage in the LNs could effectively reduce Salmonella. Salmonella Montevideo was inoculated intradermally at multiple sites and multiple times, followed by delivery of the phage cocktail subcutaneously in two injections around each of the right and left prescapular and subiliac LNs. At the conclusion of each study, animals were euthanized, and the popliteal, prescapular, and subiliac LNs were examined. The inoculated phage was successfully isolated from the LNs; transmission electron microscopy revealed phages in the LNs of the treated cattle, and these phages were identical to those in the cocktail. Levels of phage were higher (P < 0.01) in the prescapular and subiliac LNs in the phage-treated than in the control cattle. In subsequent studies, the protocols were modified to increase Salmonella and phage levels within the LNs. Compared with the first study, overall Salmonella levels were increased in the LNs, and phage treatment decreased (P < 0.01) Salmonella in the some of the LNs. Phage levels were numerically but not significantly increased (P = 0.12) in the treated cattle. The final study was modified, hypothesizing that a 48-h postmortem period before LN removal would facilitate phage-Salmonella interaction; however, no differences (P > 0.10) in Salmonella levels were found among treatments. Salmonella-specific phages administered to live cattle can translocate to the LNs; however, these phages had limited to no effect on Salmonella in these LNs under these experimental conditions.
Assuntos
Doenças dos Bovinos , Terapia por Fagos , Salmonelose Animal , Fagos de Salmonella , Animais , Bovinos , Linfonodos , SalmonellaRESUMO
The southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), is a cosmopolitan pest of high-value cash crops, including cotton (Gossypium hirsutum L.; Malvales: Malvaceae). The pest can ingest and transmit disease-causing bacterial and fungal pathogens of cotton. We hypothesized that the size of the food canal may contribute to selective transmission, as observed in previous reports. The objective of this study was to examine food canal size and other morphometric parameters of the southern green stink bug stylet bundle at two locations (labium and head) to improve our understanding of factors that may contribute to pathogen transmission. For the food canal, females possessed significantly larger canals than males, major axes were significantly longer than minor axes, and canal sizes were numerically higher at the labium compared with the head. For salivary canal, mean axes lengths were similar between sexes and the head and labium. For both food and salivary canals, axes lengths were longer and area was larger at the labium compared with the head. These findings indicate the presence of a "funnel effect" with canals becoming narrower proximally. Sex and location significantly affected the size of the intact stylet bundle. Results indicate the food canal size was not a factor affecting previously observed selective passive transmission. Major and minor axes measurements, coupled with morphological observations of canal shapes and observed "funnel effect" in the food and salivary canals, improve our understanding of the hemipteran stylet bundle and its relationship with the insect's internal morphology.
Assuntos
Heterópteros/anatomia & histologia , Animais , Produtos Agrícolas , Feminino , Gossypium , Cabeça/anatomia & histologia , Masculino , Boca/anatomia & histologia , Ductos Salivares/anatomia & histologiaRESUMO
Antimicrobial resistance levels were examined for 365 Salmonella isolates recovered from the lymph nodes (n = 224) and cecal contents (n = 141) of market-age swine at slaughter. Antimicrobial resistance testing was performed by disk diffusion using 13 antibiotics common in the treatment of disease in human and veterinary medicine. Although none of the antibiotics tested were used subtherapeutically within the last 5 years on the farms sampled, resistance to chlortetracycline, penicillin G, streptomycin, and sulfisoxazole was common. Penicillin G resistance was significantly more frequent (P = 0.03) and sulfisoxazole resistance was significantly less frequent (P < 0.01) in lymph node versus cecal isolates. Multidrug resistance was observed among 94.7% of the lymph node isolates and 93.5% of the cecal isolates. The most frequent multidrug resistance pattern included three antibiotics-penicillin G, streptomycin, and chlortetracycline. Isolates in somatic serogroup B, and more specifically, Salmonella Agona and Salmonella Schwarzengrund isolates, were often resistant to a greater number of antibiotics than were isolates in the other serogroups. Streptomycin, sulfisoxazole, ampicillin (lymph node isolates), and nitrofurantoin (cecal isolates) resistance levels differed significantly between somatic serogroups. The prevalence of penicillin G-, streptomycin-, and sulfisoxazole-resistant isolates differed significantly between serovars for both lymph node and cecal isolates. Results of this study suggest that a correlation exists between the somatic serogroup or serovar of a Salmonella isolate and its antimicrobial resistance status, which is specific to the antibiotic of interest and the source of the isolate (lymph node versus cecal contents).
Assuntos
Antibacterianos/farmacologia , Ceco/microbiologia , Linfonodos/microbiologia , Salmonella/efeitos dos fármacos , Animais , Resistência Microbiana a Medicamentos , Resistência a Múltiplos Medicamentos , Testes de Sensibilidade Microbiana , Prevalência , Salmonella/crescimento & desenvolvimento , SuínosRESUMO
An epidemiologic survey was conducted to determine the prevalence of salmonellae in swine from 5 farms of an integrated swine operation. The purpose of this study was to evaluate the recovery efficiencies for salmonellae from swine lymph nodes and cecal contents when GN Hajna and tetrathionate were compared as initial enrichments. Salmonellae were isolated from 61% of 645 pigs at slaughter; 324 positive cultures were from lymph nodes, and 224 were from cecal contents. Frequently, pigs had salmonellae isolated from both the lymph nodes and cecal contents. Total isolations, regardless of source, were similar for GN Hajna (247) and tetrathionate (301). There was no difference (P > 0.05) in the number of isolations from lymph nodes when GN Hajna enrichment was compared with tetrathionate enrichment (174 vs. 150). However, there was a significant (P < 0.05) advantage of utilizing tetrathionate when compared with GN Hajna for isolations from cecal contents (151 vs. 73).
Assuntos
Salmonelose Animal/epidemiologia , Salmonella/isolamento & purificação , Doenças dos Suínos/epidemiologia , Matadouros , Animais , Ceco/microbiologia , Meios de Cultura , Estudos Epidemiológicos , Indicadores e Reagentes , Linfonodos/microbiologia , Prevalência , Salmonelose Animal/diagnóstico , Manejo de Espécimes , Suínos , Doenças dos Suínos/diagnóstico , Ácido TetratiônicoRESUMO
Arcobacter spp. were isolated from nursing sows and developing pigs on three farms of a farrow-to-finish swine operation and market-age pigs at slaughter. Isolates were identified by polymerase chain reaction and genotypic fragment patterns were examined by pulsed-field gel electrophoresis (PFGE). Incidences of Arcobacter-positive samples increased progressively as the pigs aged, resulting in all of the pens at the end of the growth cycle in the finishing barn containing Arcobacter-positive feces. However, only 10 of 350 cecal samples from slaughtered pigs were positive. There was little similarity between genotypic patterns for Arcobacter collected from the three farms. The level of genotypic variation revealed by PFGE suggested that pigs in this farrow-to-finish operation were colonized by multiple Arcobacter parent genotypes that may have undergone genomic rearrangement, common to members of Campylobacteraceae, during successive passages through the animals. Additionally, the level of genotypic diversity seen among Arcobacter isolates from farms of a single farrow-to-finish swine operation suggests an important role for genotypic phenotyping as a source identification and monitoring tool during outbreaks.
Assuntos
Arcobacter/isolamento & purificação , Portador Sadio/veterinária , Microbiologia de Alimentos , Infecções por Bactérias Gram-Negativas/veterinária , Doenças dos Suínos/microbiologia , Fatores Etários , Animais , Arcobacter/genética , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Surtos de Doenças/prevenção & controle , Eletroforese em Gel de Campo Pulsado/veterinária , Fezes/microbiologia , Feminino , Variação Genética , Genótipo , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Incidência , Masculino , Reação em Cadeia da Polimerase/veterinária , Prevalência , Suínos , Doenças dos Suínos/epidemiologia , Texas/epidemiologiaRESUMO
The objective of the present study was to evaluate how feed withdrawal and transportation influenced the cecal environment and cecal populations of Campylobacter in swine. Four miniature Yucatan gilts (8.8 kg), naturally infected with Campylobacter jejuni, were surgically implanted with cecal cannulas. The gilts were fasted for 48 h. Samples of cecal contents were collected for 7 days prior to and for 7 days after the fast, and mean values were determined for pH, volatile fatty acids (VFA), and CFU enumeration of C. jejuni. This was replicated three times. In another trial, gilts (full-fed) were transported in a livestock trailer for 4 h and cecal samples were collected before and after transport and analyzed for pH, VFA, and CFU. Following a 48-h fast, cecal pH increased (P < 0.05) by 1 unit; acetic and propionic acids decreased (P < 0.05) by 61% and 71%, respectively; and there was a twofold log10 increase (P < 0.05) in CFU/g cecal content of C. jejuni. Values of pH, VFA, and CFU of C. jejuni did not change in cecal samples from gilts following transportation. These data are important for food safety considerations because feed withdrawal, commonly associated with shipping and slaughter, can increase Campylobacter concentrations in the pig intestinal tract.
Assuntos
Campylobacter jejuni/isolamento & purificação , Ceco/microbiologia , Jejum , Suínos/microbiologia , Animais , Campylobacter jejuni/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Ácidos Graxos Voláteis/análise , Feminino , Concentração de Íons de Hidrogênio , Meios de TransporteRESUMO
Pigs may be a natural reservoir of Campylobacter and can be colonized as early as 24 h after birth. The purpose of the present study was to evaluate what effect early removal of piglets from Campylobacter-positive sows has on Campylobacter prevalence in neonates. In two trials, piglets were removed from sows within 24 h of birth and were reared in nurseries isolated from sows for 21 days. From the neonates rectal swabs were cultured for Campylobacter, and Campylobacter status of the isolated piglets was compared to that of littermates reared on sows. The nurseries consisted of wire-floored farrowing crates that were equipped with heaters and self-feeders. In trial I, the Campylobacter prevalence in nursery-reared piglets was 13 of 14 on day 2 and 0 of 14 on day 20. Campylobacter prevalence in the sow-reared piglets was 8 of 9 from days 2 to 20. In trial II, 12 of 29 on day 2, and 5 of 26 on day 20, of the nursery-reared piglets were culture positive for Campylobacter. For the sow-reared piglets, Campylobacter prevalence was 7 of 15 on day 1 and 15 of 15 (100%) on day 20. These data suggest that successful permanent colonization of the gut by Campylobacter is probably related to constant exposure of piglets to Campylobacter-positive feces. Campylobacter prevalence may be diminished in neonates that are reared off-sow in isolated nurseries.
Assuntos
Infecções por Campylobacter/veterinária , Campylobacter/crescimento & desenvolvimento , Doenças dos Suínos/microbiologia , Criação de Animais Domésticos/métodos , Animais , Animais Recém-Nascidos , Campylobacter/isolamento & purificação , Infecções por Campylobacter/epidemiologia , Infecções por Campylobacter/microbiologia , Feminino , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Transmissão Vertical de Doenças Infecciosas/veterinária , Masculino , Prevalência , Distribuição Aleatória , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/transmissão , Fatores de TempoRESUMO
OBJECTIVE: To enumerate the prevalence of Campylobacter isolates in the intestinal tract of market-weight swine raised in an integrated swine operation in Texas. SAMPLE POPULATION: Samples of cecal contents were collected from 595 pigs (mean body weight, 110 kg [242 lb]) at time of slaughter. Pigs were off-spring of Yorkshire-Landrace sows and Duroc or Hampshire boars. Pigs originated from 4 farrow-to-finish farms. PROCEDURE: During a 9-month period, visits were made to a slaughter plant to remove cecal contents from market-weight hogs. Samples were obtained from 50 pigs/visit from designated farms so that samples were obtained 3 times from pigs of each of 4 farms. Isolation of Campylobacter spp was accomplished by use of enrichment broth and restrictive media, using microaerophilic conditions. RESULTS: Campylobacter spp were isolated from 70 to 100% of the pigs, depending on the farm and the date the samples were collected. Campylobacter coli was isolated from 20 to 100% (mean, 60%) of samples, and C jejuni was isolated from 0 to 76% (mean, 31%) of samples. Campylobacter lari was isolated from 2 pigs. Concentrations of C coli or C jejuni ranged from 10(3) to 10(7) colony-forming units/g of cecal content. CONCLUSIONS AND CLINICAL RELEVANCE: Campylobacter coli generally is accepted as a common inhabitant of the intestinal tract of swine. However, analysis of results of this study suggests that a relatively high prevalence of C jejuni may be found in pigs raised on specific farms.
Assuntos
Infecções por Campylobacter/veterinária , Campylobacter/isolamento & purificação , Ceco/microbiologia , Doenças dos Suínos/epidemiologia , Animais , Campylobacter/classificação , Infecções por Campylobacter/epidemiologia , Contagem de Colônia Microbiana/veterinária , Qualidade de Produtos para o Consumidor , Feminino , Masculino , Carne/microbiologia , Prevalência , Saúde Pública , Suínos , Doenças dos Suínos/microbiologia , Texas/epidemiologiaRESUMO
Chicken heterophils activated in vivo following the intraperitoneal (i.p.) administration of Salmonella enteritidis-immune T lymphokines (SE-ILK) have been implicated in the protection against SE organ invasion. SE-ILK induces a heterophilia and directly (or indirectly) activates the granulocytes. The invasion of SE provides the secondary signal for directing activated heterophils to the site of bacterial invasion. We examined the mechanism of adherence within the avian heterophil system using an in vitro bovine serum albumin (BSA) matrix in which neutrophil adherence is primarily CD11/CD18 integrin mediated in mammalian systems. Activated heterophils displayed a four-fold increase in receptor-mediated adherence in vitro to BSA-coated slides as compared to control heterophils from PBS-injected birds. The increased adherence of activated heterophils can be partially blocked by either anti-alpha M (CD11b) or anti-beta 2 (CD18) antibodies in a dose dependent manner. Anti-alpha 3 (CD49c) antibody partially blocked adherence of both normal and activated cells. Fluorescence-activated cell scanning (FACS) analysis of the heterophils shows that both control and SE-ILK-activated heterophils collected at 4 h post injection with SE-ILK or PBS display similar amounts of integrin alpha 3 on their surface. This integrin is constitutively expressed and is responsible for the in vitro adherence of both groups. However, antibodies to the Mac-1 complex (CD11b/CD18) block only the adherence of SE-ILK-stimulated heterophils. Thus, the CD11b/CD18 heterodimer is apparently up regulated in response to the injected SE-ILK and plays a major role in the adherence of activated heterophils. Our studies in chickens parallel human and mouse studies showing the importance of the beta 2 integrins in adherence of activated cells.
Assuntos
Moléculas de Adesão Celular/metabolismo , Galinhas/metabolismo , Linfocinas/imunologia , Ativação de Neutrófilo/imunologia , Neutrófilos/metabolismo , Salmonella enteritidis/imunologia , Animais , Adesão Celular , Citometria de Fluxo/veterinária , Antígeno de Macrófago 1/imunologia , Microscopia Eletrônica de Varredura/veterinária , Neutrófilos/ultraestrutura , Soroalbumina Bovina/metabolismoRESUMO
Epoxy resins are mixtures of several components formulated in exact proportions to assure proper polymerization. It is necessary that this composition be maintained throughout the tissue being infiltrated to avoid embedding artifacts. Unfortunately, the separate resin components will not penetrate the tissue at the same rate unless they all have the same viscosity and molecular size. Failure to meet these criteria will result in component separation during tissue infiltration and may result in severe embedding defects. This and several ancillary problems such as low tissue contrast, damage to diamond knives, and poor postsection staining are explored in this brief discussion.
Assuntos
Resinas Epóxi , Microscopia Eletrônica/métodos , Inclusão do Tecido , Animais , Difusão , HumanosRESUMO
Primary cultures of Anaplasma marginale infected erythrocytes were used to determine conditions for in vitro cultivation of the rickettsia. The infected erythrocytes that were maintained by regular addition of Glasgow's MEM with fetal calf serum and uninfected erythrocytes showed a 1-5% increase in percent infected erythrocytes on the evaluation of Giemsa stained smears. This increase in parasitemia resulted in up to 70% change in the number of infected erythrocytes. Co-culture of the infected erythrocytes with endothelial cell monolayers allowed for longer maintenance with the parasitemia ranging from 5-13% through four passages over 16 weeks. Examination of cultures using transmission electron microscopy showed initial bodies within the erythrocytes at 10 days after the initial passage of the primary culture. The endothelial cell monolayers in the co-cultures contained multiple initial bodies. We have demonstrated that A. marginale can be grown for a limited number of passages in the co-culture system, which will facilitate the development of a continuous culture of the organism.
Assuntos
Anaplasma/crescimento & desenvolvimento , Anaplasmose/sangue , Endotélio Vascular/citologia , Endotélio Vascular/microbiologia , Eritrócitos/citologia , Eritrócitos/microbiologia , Anaplasma/ultraestrutura , Animais , Bovinos , Técnicas de Cocultura , Meios de Cultura , Endotélio Vascular/ultraestrutura , Eritrócitos/ultraestrutura , Masculino , Artéria Pulmonar , Fatores de TempoRESUMO
Bacterial colonization of cecal mucosal epithelium in 3-day-old chicks administered a characterized continuous-flow (CF) culture of 29 microorganisms on the day of hatch was evaluated by scanning electron microscopy. Extensive colonization of the mucosa was noted in the ceca of CF-treated chicks, with large colonies of bacteria located predominately within and between crypts. Cecal crypts from control chicks contained only thin strands of mucus with a few bacteria. Individual cells and clumps of bacteria were observed bound to the mucosal epithelium in both CF-treated and control chicks. Colonization by CF culture bacteria was accompanied by an increase in the concentration of volatile fatty acids in the cecal contents and increased resistance to colonization by Salmonella typhimurium .
RESUMO
The effect of incubating Salmonella typhimurium and S. typhimurium cell-free extracts with isolated intestinal segments from 1-day-old chicks was evaluated using scanning electron microscopy. Incubation of segments with intact bacteria or with cell-free extract resulted in the loss of mucosal epithelial integrity after as little as 30 min incubation. Loss of mucosal epithelial integrity was evidenced by the complete shedding of the epithelium. The addition of 2.5% D-mannose to the incubation medium inhibited the loss of epithelial cells, whether intestinal segments were incubated with intact bacteria or with cell-free extract. These results indicate that S. typhimurium exerts a D-mannose-sensitive cytotoxic effect on the mucosal epithelium of isolated intestinal segments and that the cytotoxic effector is present in cell-free extracts of the bacteria.
Assuntos
Mucosa Intestinal/ultraestrutura , Manose/farmacologia , Salmonella typhimurium/patogenicidade , Animais , Sistema Livre de Células , Galinhas , Epitélio/efeitos dos fármacos , Epitélio/microbiologia , Epitélio/ultraestrutura , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/microbiologia , Intestino Delgado , Microscopia Eletrônica de Varredura , Técnicas de Cultura de Órgãos , Salmonella typhimurium/efeitos dos fármacosRESUMO
The ultrastructure of several stages of Hepatozoon canis found in dogs with clinically diagnosed infections was determined using transmission electron microscopy. Stages were found in skeletal muscle tissue that corresponded to the 'onion skin' cyst stage, as described at the light microscopic level, and were composed of an electron-transparent material that appeared to radiate from a central core. Larger cysts, walled off by fibroblasts, contained a transformed host cell located centrally within them. The parasitic stage within these transformed cells contained numerous organelles including mitochondria and Golgi apparatus, and was singularly nucleated. In cardiac muscle, a meront was observed which produced merozoites by ectomerogony. Adjacent to this meront was a granuloma containing merozoites within mononuclear phagocytes which may either serve as a reservoir of parasites for reinfection of the host or differentiate into the circulating gamont stage of the parasite. Gamonts were found within parasitophorous vacuoles inside circulating neutrophils. They had a condensed cytoplasmic appearance and were extremely electron dense with respect to other observed parasite stages. In vitro cultivation of parasitized neutrophils resulted in the appearance of a stage of the parasite with altered ultrastructure compared with gamonts found in circulating neutrophils. This stage was judged to be a possible gamete stage of the parasite.
Assuntos
Coccidiose/veterinária , Doenças do Cão/parasitologia , Eucoccidiida/ultraestrutura , Animais , Coccidiose/parasitologia , Cães , Granuloma/parasitologia , Granuloma/veterinária , Coração/parasitologia , Microscopia Eletrônica , Músculos/parasitologia , Neutrófilos/parasitologiaRESUMO
Mouse and human erythrocytes are inherently different with respect to slow dialysis encapsulation used in preparing carrier erythrocytes. Fluorescein isothiocyanate (FITC)-dextran was added to five different stages of the encapsulation process to discern when endocytic vesiculation occurred. Mouse erythrocytes were much more unstable than human cells, with as many as 50% of mouse cells showing vesicles, as determined by flow cytometry. Mouse erythrocytes showed the ability to form vesicles at each stage beyond the washed-packed-cell stage. Up to 20% of the human cells formed vesicles at stages beyond the annealed-cell stage. Although vesiculation can occur at any stage of the encapsulation process, with the exception of washed-packed cells, the actual amount of FITC-dextran incorporated in the cells is extremely low when compared with dialysis encapsulation, namely 50 ng/10(7) cells as against 2,000 ng/10(7) cells. Thus preparation of carrier erythrocytes by slow hypo-osmotic dialysis induces certain instabilities that lead to a substantial percentage of cells with endocytic vesicles, while the actual amount endocytosed is low. The differences in vesiculation observed between human and mouse erythrocytes is apparently related to the intrinsic properties of the cells and is consistent with the fact that mouse erythrocytes are more fragile when undergoing slow dialysis than are human erythrocytes.
Assuntos
Portadores de Fármacos , Endocitose , Eritrócitos/fisiologia , Animais , Dextranos , Diálise , Citometria de Fluxo , Fluoresceína-5-Isotiocianato/análogos & derivados , Humanos , Camundongos , Microscopia de Fluorescência , Espectrometria de FluorescênciaRESUMO
Babesia odocoilei continuously cultured in white-tailed deer (Odocoileus virginianus) erythrocytes was examined by transmission and scanning electron microscopy. Merozoites, trophozoites, intermediate-stage forms, and dividing forms were observed. Merozoites possessed a single nucleus, inner membrane complex, rhoptries, free ribosomes, rough endoplasmic reticulum, and single membrane-bound vesicles. Trophozoites lacked an inner membrane complex and rhoptries. Intermediate stages were characterized by distinct segments of inner membrane complex. Dividing forms ranged from cells with an elongated nucleus to mature daughter cells joined by a ringlike structure. Babesia odocoilei was characterized by its close proximity to the erythrocyte membrane, membranous structures resembling feeding organelles, and reproduction via a method resembling budding sensu stricto.
Assuntos
Babesia/ultraestrutura , Babesiose/parasitologia , Cervos/parasitologia , Eritrócitos/parasitologia , Animais , Babesia/citologia , Babesia/crescimento & desenvolvimento , Divisão Celular , Cervos/sangue , Microscopia Eletrônica , Microscopia Eletrônica de VarreduraRESUMO
Babesia bovis cultured in bovine erythrocytes was passaged into white-tailed deer (Odocoileus virginianus) erythrocytes and medium containing either white-tailed deer serum or bovine serum. Deer erythrocytes supported the growth of the parasite only in the presence of bovine serum. Cryopreserved cultures were recovered successfully in white-tailed deer erythrocytes. By light and electron microscopy, B. bovis structure appeared similar in host cells of either species.
Assuntos
Babesia bovis/crescimento & desenvolvimento , Cervos/sangue , Eritrócitos/parasitologia , Animais , Babesia bovis/ultraestrutura , Preservação de Sangue/veterinária , Bovinos , Células Cultivadas , Criopreservação/veterinária , Meios de Cultura , Eritrócitos/ultraestrutura , Masculino , Microscopia EletrônicaRESUMO
Carrier erythrocytes are used to disseminate drugs in the circulatory system of animals. Carrier erythrocytes prepared from white-tailed deer (Odocoileus virginianus) do not circulate well in vivo. Although carrier cells were prepared from sickle and non-sickle cells with no apparent differences, their 24-hour survival was only 10 per cent. Osmotic fragility of carrier cells was increased over that of normal deer erythrocytes. Unlike erythrocytes from other ruminants, deer carrier erythrocytes are extremely fragile. Scanning electron micrographs of deer erythrocytes (sickle or non-sickle) in different stages of carrier cell preparation revealed no morphological differences. These data suggest that carrier cells from deer would not be amenable for use in long-term dissemination of drugs.
Assuntos
Cervos/sangue , Eritrócitos/ultraestrutura , Animais , Portadores de Fármacos , Envelhecimento Eritrocítico , Eritrócitos/fisiologia , Inulina/metabolismo , Microscopia Eletrônica de Varredura , Fragilidade Osmótica , Sacarose/metabolismoRESUMO
A method was explored to develop a general means to target erythrocytes to T-cells in vitro. Mouse erythrocytes were coupled with an anti-Thy-1.2 monoclonal antibody by two methods. Chromic chloride coupling of antibody was preferred to biotinylation. The morphology, osmotic fragility, and the hematological values of treated cells were normal compared with those of control erythrocytes. Antibody-coupled erythrocytes were incubated with cytotoxic T-lymphocytes (CTLL) in vitro at a 20:1 ratio. Approximately 60-70% of the CTLL formed rosettes. The cell mixture was subjected to gradient centrifugation and separated into four fractions. THe rosettes were clearly identified only in the treated group containing anti-Thy-1.2-coupled erythrocytes. No rosettes were found when aspecific monoclonal antibody was coupled to erythrocytes. Examination by scanning and transmission electron microscopy revealed CTLL with 4-5 erythrocytes attached to them but did not show any evidence of membrane fusion. Rosettes of CTLL incubated in vitro proliferated as well as CTLL alone and maintained their dependency on interleukin-2. Targeting of erythrocyte carriers to lymphocytes offers the potential for delivery of molecules directly to the target cell.