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1.
Conserv Physiol ; 12(1): coae003, 2024.
Article in English | MEDLINE | ID: mdl-38343723

ABSTRACT

Obtaining endocrinological profiles using non-invasive methodologies by the measurement of hormone fecal metabolites is a widely used method to monitor ovarian activity and pregnancy in wild species. These tools allow the obtention of physiological information without causing capture-related stress on the individuals. In this research, we aimed to 1) biologically validate a non-invasive method to assess fecal progestagens and estrogens fluctuations during gestation in guanacos (Lama guanicoe) and 2) apply this technique to assess pregnancy in a wild free-ranging population. Fecal samples were collected through the gestation period (~12 months) of female guanacos in a 6.5-ha paddock. An increase in fecal metabolites of both hormones was detected. Progestagens increased gradually, in contrast to estrogens, which remained at basal values for most of the gestation period and peaked only a few days before calving. To assess pregnancy in wild free-ranging animals, fecal samples were collected from a population of La Payunia provincial reserve (Mendoza, Argentina) during the beginning of gestation and at the end of gestation. Through the first months of possible gestation, pregnant females represented between 40 and 80% of the population; at the end of gestation, only 20-40% of the females had confirmed pregnancies. Our results demonstrated that the polyclonal antisera and sexual hormone metabolite assays used here detect variations in the metabolites excreted through feces in guanacos and provide the possibility of non-invasive hormone monitoring of female reproductive status. Also, the findings in wild conditions suggest that natural abortions could have occurred during the first months of gestation. Although some abortions may be natural, the harsh environmental conditions that challenge the support of such a long gestational process may be another relevant factor to consider. The results obtained here enhance our understanding of the reproductive physiology of one of the most emblematic ungulates in South America.

2.
Arq. bras. med. vet. zootec. (Online) ; 71(4): 1387-1394, jul.-ago. 2019. tab
Article in Portuguese | VETINDEX, LILACS | ID: biblio-1038596

ABSTRACT

Objetivou-se, com este estudo, verificar a influência da suplementação com diferentes associações entre minerais orgânicos sobre o desempenho e as características de carcaça, bem como avaliar sua viabilidade econômica, para suínos em terminação. Foram utilizados 88 machos castrados, divididos entre quatro tratamentos: controle com dieta basal e suplementação com CrFe, MgSe e CrFeMgSe, durante os 28 dias que antecederam o abate. O delineamento experimental foi em blocos ao acaso, com parcela experimental representada por dois animais. Os animais suplementados com CrFeMgSe apresentaram piores índices de peso final, ganho de peso diário e consumo durante todo o período, com consequente redução no peso de carcaça, menor profundidade de lombo, área de olho-de-lombo e menor quantidade de carne magra na carcaça. Houve um aumento no custo da dieta para os grupos CrFe, MgSe e CrFeMgSe, respectivamente. O uso de cromo mais ferro e magnésio mais selênio, associados dois a dois, não altera os parâmetros de desempenho e as características de carcaça. A associação dos quatro minerais, no entanto, promove piora nessas características e aumenta o custo da dieta.(AU)


This study aimed to verify the influence of supplementation with different associations between organic minerals on performance, carcass characteristics and economic viability for finishing swine. 88 castrated males were divided in four treatments: control with basal diet and supplementation with CrFe, MgSe and CrFeMgSe during the 28 days prior to slaughter. The experimental design was randomized blocks with an experimental plot represented by two animals. The animals supplemented with CrFeMgSe had worse final weight, daily weight gain and consumption throughout the period, with consequent reduction in carcass weight, lower loin depth, loin eye area and amount of lean meat. There was an increase in the effective operational cost of diet with CrFe, MgSe and CrFeMgSe groups, respectively. The use of chromium plus iron and magnesium plus selenium, associated two by two, did not alter the performance parameters and carcass. However, the four minerals association promote a worsening in these characteristics and increase the cost of production.(AU)


Subject(s)
Animals , Swine , Dietary Minerals/administration & dosage , Dietary Supplements/economics , Animal Feed/economics , Costs and Cost Analysis
3.
Reproduction ; 156(4): 331-341, 2018 10 01.
Article in English | MEDLINE | ID: mdl-30306766

ABSTRACT

The purpose of this study was to evaluate the intragestational role of ghrelin in offspring development and reproductive programming in a mouse model of ghrelin imbalance during pregnancy. Female mice were injected with ghrelin (supraphysiological levels: 4 nmol/animal/day), antagonist (endogenous ghrelin inhibition with (D-Lys3)GHRP-6, 6 nmol/animal/day) or vehicle (control = normal ghrelin levels) throughout the pregnancy. Parameters evaluated in litters were growth, physical, neurobiological and sexual development and, at adulthood, reproductive function. Litter size and initial weight did not vary between treatments. Male pups from dams treated with ghrelin showed higher body weight increase until adulthood (31.7 ± 0.8 vs control = 29.7 ± 0.7, n = 11­14 litters/treatment; P < 0.05). Postnatal physical and neurobiological development was not modified by treatments. The antagonist accelerated male puberty onset, evidenced as earlier testis descent and increased relative testicular weight (antagonist = 0.5 ± 0.0% vs ghrelin = 0.4 ± 0.0% and control = 0.4 ± 0.0%, n = 5­10 litters/treatment; P < 0.05). At adulthood, these males exhibited lower relative testicular weight and reduced sperm motility (63.9 ± 3.6% vs control = 70.9 ± 3.3 and ghrelin = 75.6 ± 3.0, n = 13­15 animals; P < 0.05), without changes in plasma testosterone or fertility. Female pups intragestationally exposed to the antagonist showed earlier vaginal opening (statistically significant only at Day 25) and higher ovarian volume (antagonist = 1085.7 ± 64.0 mm3 vs ghrelin = 663.3 ± 102.8 mm3 and control = 512.3 ± 116.4 mm3; n = 4­6 animals/treatment; P < 0.05), indicating earlier sexual maturation. At adulthood, these females and those exposed to ghrelin showed a tendency to higher percentages of embryo loss and/or foetal atrophy. In conclusion, ghrelin participates in reproductive foetal programming: alterations in ghrelin activity during pregnancy modified body weight increase and anticipated puberty onset, exerting (or tending to) negative effects on adult reproductive function.


Subject(s)
Ghrelin/physiology , Prenatal Exposure Delayed Effects , Sexual Development , Animals , Female , Male , Mice , Pregnancy , Reproduction
4.
J Anim Sci ; 93(6): 2872-84, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26115274

ABSTRACT

The objective of this study was to evaluate the effects of ractopamine (Rac) and Arg fed to pregnant sows from d 25 to 53 of gestation on fetal muscle development as well as the performance and carcass characteristics of the progeny. One hundred sows were divided into 4 treatments including a control diet, the control plus 1% Arg, the control plus 20 mg/kg Rac, and the control diet supplemented with both additives at the same levels as those used separately. During the farrowing process the data evaluated were the weight of placenta to calculate the placental efficiency and the number of piglets born alive, stillborn, and mummified. To evaluate the fiber number and area, 12 male piglets from each treatment were euthanized to harvest semitendinosus muscle. During the lactation, the preweaning mortality, weaned weights, and number of piglets weaned per litter were evaluated. After weaning, the pig performance was evaluated until the slaughter following the sow treatment. At end of finishing phase, 1 male pig of each treatment replicate was selected to evaluation the carcass and pork quality. All variables measured were analyzed using the MIXED procedure of SAS and least squares means were compared using the Tukey test with P < 0.05. The control diet + supplementation of 1.0% of L-Arg + 20 mg/kg of ractopamine HCl from d 25 to 53 of gestation (Arg+Rac) treatment had a greater number of stillborn piglets (P = 0.014) than the control group. Piglet birth weights from sows fed Rac were 11% greater (P = 0.031) than those of piglets of the control treatment. The semitendinosus muscle fiber diameters of piglets at birth from sows that received Arg, Rac, and Arg+Rac were greater (P < 0.0001) than those of control piglets, and as consequence, the fiber number per square millimeter decreased (P < 0.0001). The final nursery BW of progeny from sows fed Arg and Rac individually were greater (P = 0.010) than those of progeny of the control group. At 110 d of age, in the beginning of the finisher 1 phase, pigs from Arg-fed sows were 1.9 kg heavier (P = 0.010) than pigs from the Arg+Rac-fed sows. The HCW were 2.97 and 1.64 kg heavier (P < 0.0001) for progeny of the Arg and Rac sows, respectively, compared with those of progeny of the control. In conclusion, the trial showed that the use of Rac for gestating sows increased the piglets' weight at birth. The size of muscular fiber was increased in the semitendinosus muscle of piglets originating from sows receiving Rac or Arg. However, the combination of both compounds did not have an additive effect in comparison with the control treatment but increased the stillbirth number.


Subject(s)
Arginine/pharmacology , Dietary Supplements , Muscle, Skeletal/growth & development , Phenethylamines/pharmacology , Sus scrofa/growth & development , Animals , Arginine/administration & dosage , Birth Weight/drug effects , Birth Weight/physiology , Body Weight/drug effects , Body Weight/physiology , Female , Fetus/drug effects , Fetus/physiology , Least-Squares Analysis , Male , Muscle, Skeletal/drug effects , Phenethylamines/administration & dosage , Pregnancy , Swine
5.
Transpl Infect Dis ; 17(4): 610-2, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26061146

ABSTRACT

Lactobacillus rhamnosus is a rare clinical pathogen. A case of bacteremia caused by L. rhamnosus in a kidney transplant recipient is described. Once considered only as a contaminant or a low-virulence organism, L. rhamnosus might be an opportunistic pathogen in immunocompromised patients. To our knowledge, this is the first report of primary bloodstream infection caused by L. rhamnosus in a kidney transplant recipient.


Subject(s)
Bacteremia/diagnosis , Immunocompromised Host , Kidney Transplantation , Lacticaseibacillus rhamnosus/isolation & purification , Postoperative Complications/diagnosis , Adult , Bacteremia/immunology , Female , Humans , Postoperative Complications/immunology
6.
Arq. bras. med. vet. zootec ; 67(2): 535-546, Mar-Apr/2015. tab
Article in English | LILACS, VETINDEX | ID: lil-747057

ABSTRACT

The aim of this work was to evaluate the effects of adding different levels of glycerin in the feeding on the lipid profile and cholesterol of the meat of finishing pigs. The experiment was arranged in a completely randomized design (CRD) with factorial 5x2, being five levels of glycerin in the diet and two genders. Sixty (60) swine of the Topigs genetics (30 barrows and 30 gilts) were used; they presented initial average weight of 79.3+4.0kg and were finished with the weight of 106.2+4.5kg. The levels of glycerin utilized were 0, 50, 100, 150 and 200g/kg in the natural matter. The analyses of lipid and cholesterol profile were conducted in the muscles longissimus dorsi (loin) andsemimembranosus (ham) on the left side of the carcasses. Interaction occurred between the levels of crude glycerin in the diet and the sexual category for the profile of fatty acids and cholesterol. On the loin the meat of the barrows presented higher means of C16:0, C16:1, C20:3ω3, C18:1ω9c, Total of saturated (SFA) and monounsaturated (MUFA) fatty acids. On the ham, increased means were found for the fatty acids C18:1ω9c, MUFA, activity of ∆9-desaturaseC18 and ElongaseC16-18 in barrows. The sows' meat presented higher proportions of polyunsaturated fatty acids and of the series ω6 for both the cuts. The amount of cholesterol in the sows' meat presented increase according to the level of glycerin in the meat. The barrows' meat presented indices of atherogenicity greater than the gilts. The levels of glycerin altered the lipid profile and cholesterol content according to the sexual category, promoting a distinct effect on the loin and ham.(AU)


O objetivo deste trabalho foi avaliar os efeitos do fornecimento de diferentes níveis de glicerina na alimentação sobre o perfil lipídico e colesterol da carne de suínos em terminação. O delineamento experimental foi organizado inteiramente ao acaso (DIC), com fatorial 5x2, sendo: cinco níveis de glicerina na dieta e dois sexos. Foram utilizados 60 suínos da genética Topigs (30 machos castrados e 30 fêmeas), apresentando peso médio inicial de 79,3+4,0kg, e foram terminados com peso de 106,2+4,5kg. Os níveis de glicerina utilizados foram de 0, 50, 100, 150 e 200g/kg na matéria natural. As análises de perfil lipídico e de colesterol foram realizadas nos músculos longissimus dorsi (lombo) e semimembranosus (pernil) do lado esquerdo das carcaças. Ocorreu interação entre os níveis de glicerina bruta na dieta e a categoria sexual para o perfil de ácidos graxos e colesterol. A carne dos machos castrados apresentou no lombo maiores médias de C16:0, C16:1, C20:3ω3, C18:1ω9c, Total de ácidos graxos Saturados (SFA) e Monoinsaturados (MUFA). No pernil, maiores médias foram verificadas para os ácidos graxos C18:1ω9c, MUFA, atividade da ∆9-desaturaseC18 e ElongaseC16-C18 em machos castrados. A carne das fêmeas suínas apresentou maiores proporções de ácidos graxos poli-insaturados e da série ω6 para ambos os cortes. A quantidade de colesterol na carne das fêmeas suínas apresentou aumento em função do nível de glicerina na dieta. A carne dos machos castrados apresentou maiores índices de aterogenicidade que das fêmeas. Os níveis de glicerina alteraram o perfil lipídico e teor de colesterol em função da categoria sexual, promovendo efeito diferenciado no lombo e pernil.(AU)


Subject(s)
Animals , Swine , Cholesterol , Glycerol/administration & dosage , Lipids , Animal Feed , Meat/analysis
7.
Arq. bras. med. vet. zootec ; 66(2): 583-592, Jan.-Apr. 2014. graf, tab
Article in Portuguese | LILACS | ID: lil-709301

ABSTRACT

O objetivo deste trabalho foi avaliar os efeitos do fornecimento de diferentes níveis de glicerina na alimentação sobre a qualidade da carne de suínos em terminação. Foram utilizados 30 machos castrados e 30 fêmeas que apresentaram peso inicial de 79,3±4,0kg. Utilizou-se delineamento em blocos casualizados (peso inicial) em esquema fatorial 2 × 4 + 2, sendo duas categorias sexuais (macho castrado e fêmea), quatro níveis de glicerina bruta (50, 100, 150 e 200g/kg) e dois grupos controle (macho castrado e fêmea alimentados com dieta sem glicerina), totalizando dez tratamentos com seis repetições e a unidade experimental representada por um animal. Após o abate, foram realizadas as análises físico-químicas e centesimais dos músculos Longissimus dorsi (lombo) e Semimembranosus (pernil) do lado esquerdo das carcaças. Os resultados mostraram interação entre os níveis de glicerina e sexo para a intensidade de vermelho e cinzas no pernil. Observou-se que, nos corte do lombo, o pH final dos machos castrados foi maior do que o das fêmeas suínas. Os resultados indicaram que suínos machos castrados apresentaram maior teor de extrato etéreo no pernil e no lombo quando comparados às fêmeas. No pernil, o teor de cinzas das fêmeas suínas foi superior ao dos machos castrados. Entretanto, no lombo, não se verificou influência dos níveis de glicerina sobre a composição centesimal. Contudo, apesar de o uso da glicerina ter ocasionado modificação na cor vermelha e teor de cinzas no pernil de machos castrados, de forma geral não provocou mudanças relevantes sobre as características físico-químicas e centesimais da carne de suínos, podendo ser utilizada até o nível de 200g/kg na alimentação desses animais...


The objective of this study was to evaluate the effects of providing different levels of glycerin in the diet on meat quality of finishing pigs. 30 barrow and 30 female pigs were used, with initial weight of 79.3±4.0kg. A randomized block design was used (initial weight) in a factorial 2 x 4 + 2, being two sex categories (barrow and female), four levels of crude glycerin (50, 100, 150 and 200g/kg) and two control groups (barrow and female fed diet without glycerin), in a total of ten treatments with six replications and the experimental unit represented by an animal. After slaughter were carried out the physico-chemical and centesimal analysis of Longissimus dorsi (loin) and Semimembranosus (ham) on the left side of the carcasses. The results showed interaction between barrows and levels of glycerin to the redness and ash of the ham. It was observed that in the loin cut the final pH of the barrows was higher than the female pigs. The results indicate that barrows had higher ether extract content in the ham and loin compared to females. In the shank, the ash content of sows was higher than that of barrows. However, in the loin, there was no influence of the levels of glycerin on chemical composition. Nevertheless, despite the use of glycerin having caused changes in the red color and ash content in the leg of castrated males, in general it did not cause significant changes on the physico-chemical and centesimal characteristics of pork and can be used up to the level of 200g/kg in the feed of these animals...


Subject(s)
Animals , Male , Female , Animal Feed , Meat/classification , Glycerol/administration & dosage , Swine/growth & development , Food Quality , Muscles/anatomy & histology
8.
J Anim Physiol Anim Nutr (Berl) ; 97(5): 896-903, 2013 Oct.
Article in English | MEDLINE | ID: mdl-22882138

ABSTRACT

The objective of this study was to determine the apparent metabolisable energy corrected for nitrogen balance (AMEn) of some products containing glycerine from soybean oil (GOIL), a mixture of frying oil and lard (GMIX) and a semi-purified process (GSP) in broilers of different ages (10, 20, 30 and 40 days post-hatching), using two methodologies. In trial 1, the basal diets were replaced with 100 g/kg of each studied glycerine product and the diets were supplied ad libitum. Three hundred broilers were used in five replicates, with five, four, three and three animals per cage in each age group, respectively. The AMEn was calculated for each experimental unit. In trial 2, dietary treatments included the addition of glycerine at 0, 40, 80 or 120 g/kg for each crude glycerine product, with 900 broilers in six replicates, using the same number of animals per cage as described in trial 1. Depending on the experimental unit, the feeding was restricted in 88%, 92%, 96% and 100% of estimated intake according to the Cobb guide. The AMEn was determined using linear regression between the feed intake and the AMEn of each diet. In both trials, the total excreta collection method was used. Because of the chemical composition, GMIX was not considered crude glycerine. The mean AMEn values of the products were 20.55 MJ/kg, 15.80 MJ/kg and 15.05 MJ/kg for GMIX, GSP and GOIL, respectively. There was a linear decrease (p < 0.01) in the AMEn values with the increasing age of the broilers. Numerically, it was observed that the AMEn values decreased until 28-30 day post-hatching and then remained constant until the finishing phase. It is concluded that products containing glycerine can be used as an energy source for broilers, but that AMEn values can vary according to age. Younger broilers have a higher capacity of energy utilisation from these feedstuffs.


Subject(s)
Aging/physiology , Animal Feed/analysis , Chickens/metabolism , Diet/veterinary , Glycerol/metabolism , Animal Nutritional Physiological Phenomena , Animals , Biofuels , Dietary Fats/analysis , Soybean Oil/analysis
9.
Arq. bras. med. vet. zootec ; 63(6): 1519-1525, dez. 2011. tab
Article in Portuguese | LILACS | ID: lil-608977

ABSTRACT

Dois experimentos foram realizados para avaliar a influência de duas porcentagens de lisina associada à restrição alimentar sobre o desempenho e balanço de nitrogênio de suínos em terminação. No experimento I, foram utilizados 48 suínos machos castrados, com média de peso de 76,2±2,3kg, distribuídos em delineamento em blocos ao acaso, em esquema fatorial 2x2 (duas porcentagens de lisina total - normal ou com 30 por cento a mais - e duas formas de arraçoamento - à vontade ou com restrição). Com 28 dias, a porcentagem de inclusão de lisina não influenciou o ganho de peso, mas a porcentagem mais alta resultou em menor consumo e melhor conversão alimentar. A restrição alimentar diminuiu o ganho de peso sem afetar a conversão alimentar. No experimento II, 24 suínos machos castrados, com média de peso de 74,1±2,5kg, foram alojados em gaiolas de metabolismo para receber os mesmos tratamentos. Aos 14 dias de experimento, as dietas não influenciaram a absorção de nitrogênio e a ureia plasmática, porém a dieta ad libitum com a maior porcentagem de lisina reduziu a retenção de nitrogênio. Aos 28 dias, essa mesma dieta aumentou a concentração de ureia plasmática. Conclui-se que o aumento da lisina nas rações melhora o desempenho de suínos machos castrados em terminação, independentemente da forma de arraçoamento, e que a restrição alimentar, nesta fase, não é benéfica.


Two experiments were led to evaluate the influence of two percentages of lysine associated to feed restriction over performance and nitrogen balance of finishing barrows. In experiment I, 48 barrows were used, weighing 76.2±2.3kg, distributed in a randomized blocks design in factorial scheme 2x2 (two levels of total lysine - normal or added in 30 percent - and two feed programs - restricted or ad libitum). At 28 days, the levels of lysine did not influence weight gain, but the higher level provided lesser feed intake and better feed:gain. The feed restriction decreased the weight gain without affecting feed:gain. In Experiment II, 24 barrows, weighing 74.1±2.5kg, were put in metabolic cages to receive the same previously described treatments. At 14 days of the experiment, the diets did not influence the nitrogen absorption and the plasmatic urea, however, the ad libitum diet associated at the higher lysine level reduced nitrogen retention. At 28 days, this same diet increased the plasmatic urea concentration. It was concluded that the increase of lysine levels in diets improves performance in finishing barrows, regardless of the feed program, and feed restriction, in this phase, is not beneficial.

10.
Epidemiol Infect ; 139(3): 411-8, 2011 Mar.
Article in English | MEDLINE | ID: mdl-20513254

ABSTRACT

This study assessed risk factors for 30-day mortality in 66 patients with carbapenem-resistant Acinetobacter baumannii (CRAB) infection or colonization during an outbreak in an intensive-care unit. Clinical and demographic characteristics were evaluated. The overall 30-day mortality was 47·0%. In the multivariate Cox regression model, septic shock [adjusted hazard ratio (aHR) 5·01, 95% confidence interval (CI) 2·32-10·01] and APACHE II score at onset of infection (aHR 1·11, 95% CI 1·04-1·18) were significantly associated with 30-day mortality. Administration of appropriate therapy was a protective factor, but it was not statistically significant (aHR 0·48, 95% CI 0·21-1·12). A sample of isolates tested (n=27) carried the blaOXA-23 gene. Severity of baseline condition and severity of infection presentation were major risk factors for mortality during the outbreak. Patients who received appropriate therapy tended to have lower mortality rates, although therapy was started late and dosage was suboptimal in most cases.


Subject(s)
Acinetobacter Infections/epidemiology , Acinetobacter Infections/mortality , Acinetobacter baumannii/drug effects , Carbapenems/pharmacology , Disease Outbreaks , beta-Lactam Resistance , APACHE , Acinetobacter Infections/complications , Acinetobacter Infections/pathology , Acinetobacter baumannii/isolation & purification , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Cross Infection/epidemiology , Cross Infection/mortality , Cross Infection/pathology , Female , Humans , Intensive Care Units , Male , Risk Factors , Shock, Septic/mortality , Shock, Septic/pathology
11.
Transplant Proc ; 36(4): 891-3, 2004 May.
Article in English | MEDLINE | ID: mdl-15194306

ABSTRACT

Cytomegalovirus (CMV) infection is the single most frequent infectious complication in renal transplant recipients. The purpose of this study was to analyze the diagnostic efficacy of PCR-RFLP compared to antigenemia for CMV disease (CMVD) in kidney transplant recipients. From November 2001 to February 2002, 19 renal adult transplant recipients were followed with weekly measurements of CMV pp65 antigen to monitor the activity of CMV from the week 4 to 12 posttransplantation. Only 4 (21.1%) patients did not develop viremia during the first 12 posttransplantation weeks. Active infection was observed in 15 patients (78.9%): asymptomatic viremia in 6 (31.6%) and CMVD in 9 (47%). All patients who developed CMVD showed positivity in both methods during the observation period. The number of positive cells ranged from 11 to 292 cells in patients with CMVD and one to eight cells among those with asymptomatic viremia. Both methods revealed 100% sensitivity for CMVD diagnosis. The specificity was 60% for antigenemia and 70% for PCR, with positive predictive values of 60% and 75%, respectively.


Subject(s)
Antigens, Viral/blood , Cytomegalovirus Infections/epidemiology , Cytomegalovirus/isolation & purification , Kidney Transplantation/statistics & numerical data , Phosphoproteins/blood , Viral Matrix Proteins/blood , Acute Disease , Cytomegalovirus/genetics , Humans , Polymerase Chain Reaction/methods , Polymorphism, Restriction Fragment Length , Predictive Value of Tests , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity , Viremia/epidemiology
12.
Cell Microbiol ; 3(11): 745-51, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11696034

ABSTRACT

Enteropathogenic Escherichia coli (EPEC) is able to inject its own receptor, a transmembrane protein called translocated intimin receptor, Tir, into the host epithelial cell. The bacterium then uses an outer membrane protein, intimin, to bind to Tir and remains firmly attached to the host cell surface for the duration of the infection. The bacterium is also able to trigger the rearrangement of several host cell proteins, culminating with the formation of an actin-rich, pedestal-like structure beneath the EPEC adherence site. Although several cytoskeletal proteins are rearranged following EPEC infection, the exact role played by these proteins during pedestal formation remains unknown. We report here that talin, an integrin-binding protein, is recruited by EPEC and associates directly with Tir. By surface plasmon resonance (SPR), the predicted value for the dissociation constant (KD) for Tir-talin binding was 1.86 x 10(-7) M. We also demonstrate that microinjection of anti-talin antibodies into HeLa cells resulted in the complete inability to focus actin filaments beneath the attached bacterium. These findings demonstrate that talin is essential for EPEC-induced pedestal formation in infected cells.


Subject(s)
Escherichia coli Proteins , Escherichia coli/physiology , Escherichia coli/pathogenicity , Receptors, Cell Surface/metabolism , Talin/metabolism , Actins/metabolism , Escherichia coli Infections/microbiology , HeLa Cells , Humans , Protein Binding , Surface Plasmon Resonance , Virulence
13.
J Med Microbiol ; 49(9): 801-810, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10966228

ABSTRACT

Thermostable direct haemolysin (TDH) produced by Vibrio parahaemolyticus is thought to play an important role in the severe diarrhoea caused by this organism. This study investigated the enterotoxicity of TDH for human intestinal cells. Addition of TDH to the mucosal side of human colonic tissue in Ussing chambers caused increased short circuit currents (Isc), a process that was inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), an inhibitor of Ca2+ -activated chloride (Cl-) channels. With human colonic epithelial (Caco-2) cells, high Isc and intracellular Ca2+ concentrations ([Ca2+]in) were detected after the addition of TDH to the apical side of the cell monolayer. The Isc decreased with the addition of DIDS, but not with glybenclamide, 5-nitro-2-(3-phenylpropylamino) benzoic acid, or gadolinium chloride. No Isc increase with TDH was observed when the Cl- in the medium was replaced by gluconate or when Ca2+ was depleted. Similarly, TDH did not raise [Ca2+]in after depletion of extracellular Ca2+. R7, a mutant form of TDH, reduced the effects of TDH on Isc and [Ca2+]in, as did protein kinase C (PKC) inhibitors. Thus, TDH increases Cl- secretion in human colonic epithelial cells, apparently through mechanisms involving cell binding and Ca2+ influx, followed by elevation of [Ca2+]in associated with PKC phosphorylation.


Subject(s)
Chlorides/metabolism , Enterotoxins/pharmacology , Hemolysin Proteins/pharmacology , Intestines/drug effects , Vibrio parahaemolyticus/pathogenicity , 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid/pharmacology , Bacterial Toxins , Biological Transport , Caco-2 Cells , Calcium/metabolism , Cell Line , Chloride Channels/antagonists & inhibitors , Colon/cytology , Colon/drug effects , Diffusion Chambers, Culture , Electric Conductivity , Enterotoxins/genetics , Hemolysin Proteins/genetics , Humans , Intestinal Mucosa/cytology , Intestinal Mucosa/drug effects , Intestines/cytology , Protein Kinase C/antagonists & inhibitors , Recombinant Proteins/pharmacology
14.
Infect Immun ; 68(1): 382-6, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10603412

ABSTRACT

Infection of cultured HeLa epithelial cells with enteropathogenic Escherichia coli (EPEC) or enterohemorrhagic E. coli (EHEC) O157:H7 results in accumulation of cortactin under the adherent bacteria. Tyrosine phosphorylation of cortactin is not induced following HeLa cell infection with EHEC or EPEC, contrary to what has been reported to occur with Shigella flexneri.


Subject(s)
Bacterial Adhesion/physiology , Escherichia coli O157/pathogenicity , Escherichia coli/pathogenicity , Microfilament Proteins/physiology , Actins/metabolism , Binding Sites , Cortactin , Cytochalasin D/pharmacology , Enzyme Inhibitors/pharmacology , Escherichia coli/physiology , Escherichia coli O157/physiology , HeLa Cells , Humans , Microscopy, Confocal , Phosphorylation , Protein Binding , Protein-Tyrosine Kinases/antagonists & inhibitors , Shigella flexneri/pathogenicity , Shigella flexneri/physiology , Staurosporine/pharmacology , Tyrosine/metabolism , Virulence
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