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1.
J Neuroendocrinol ; 29(8)2017 08.
Article in English | MEDLINE | ID: mdl-28718206

ABSTRACT

With the aim of studying delta-like protein 1 (DLK1) with respect to the relationship between adipocyte leptin and adenohypophyseal hormones, we carried out an immunohistochemical study analysing the presence of receptors for these hormones in the pituitary and adipose cells of male wild-type (WT) mice (Dlk1+/+ ) compared to knockout (KO) mice (Dlk1-/- ). The mRNA expression of these molecules was also determined using the reverse transcriptase-polymerase chain reaction. The results obtained showed that, in WT adipose cells, all of the adenohypophyseal hormone receptors were present, with a higher mRNA expression for growth hormone (GH) receptor and thyroid-stimulating hormone (TSH) receptor. Of the total cells in the anterior pituitary lobe, 17.09±0.9% were leptin receptor (LEPR) immunoreactive (-IR), mainly in GH-IR and prolactin (PRL)-IR cells (41.5±3.8%; 13.5±1.7%, respectively). In Dlk1-/- mice, adipocyte cells showed a significant increase in the TSH receptor mRNA expression level. Moreover, the percentage of LEPR-IR GH cells showed a statistically significant increase compared to controls, from 41.5±3.8% to 53.1±4.0%. By contrast, only 3.0±0.6% of LEP-IR anterior pituitary cells were detected in Dlk1 KO mice, as opposed to 6.8±1.1% observed in WT mice. The results suggest that relationships exist between adipocytes and pituitary GH, PRL and TSH cells, in addition to an influence with respect to the synthesis and release of pituitary leptin, particularly in PRL cells.


Subject(s)
Adipose Tissue/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Pituitary Gland/metabolism , Animals , Intracellular Signaling Peptides and Proteins/genetics , Male , Membrane Proteins/genetics , Mice , Mice, Knockout , Pituitary Hormones, Anterior/metabolism , Prolactin/metabolism , RNA, Messenger/metabolism , Receptors, Leptin/metabolism , Receptors, Somatotropin/metabolism , Receptors, Thyrotropin/metabolism
2.
J Neuroendocrinol ; 23(9): 849-59, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21756269

ABSTRACT

To better understand the role of the non-canonical Notch ligand delta-like protein 1 (DLK1), in hormone-producing cells, we studied the cell distribution and subcellular localisation of DLK1 in the pituitary of male adult 129/SvJ mice, and analysed the variations in the hormone-producing cells associated with the lack of this gene in Dlk1 knockout mice. The results obtained showed the presence of DLK1-immunoreactive (ir) cells in all hormone-producing cells of the anterior pituitary. Immunoelectron microscopy showed DLK1-ir in the rough endoplasmic reticulum and inside secretory vesicles, suggesting that DLK1 is released together with pituitary hormones. Moreover, we found that prolactin (PRL)-DLK1-ir cells are in intimate contact with follicle-stimulating hormone (FSH)-ir-DLK1-negative cells. In Dlk1 knockout mice, we detected a significantly lower number of gowth hormone (GH)-ir cells, a reduction in the FSH and PRL immunostaining intensity, and a significant decrease in FSH mRNA expression compared to wild-type mice. An increase in pituitary GH mRNA expression and serum leptin levels was also found. These findings provide evidence supporting several regulatory functions of DLK1 in the pituitary gland.


Subject(s)
Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Pituitary Gland/cytology , Pituitary Gland/metabolism , Receptors, Notch/metabolism , Animals , Follicle Stimulating Hormone/genetics , Follicle Stimulating Hormone/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Leptin/blood , Ligands , Male , Membrane Proteins/genetics , Mice , Mice, Knockout
3.
Lett Appl Microbiol ; 52(1): 49-55, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21118278

ABSTRACT

AIM: To evaluate the association of the polar and lateral flagella with biofilm formation on plastic surfaces in 76 Aeromonas caviae strains isolated from environment (lagoon water), food (vegetables, fish and cheese) and human source (faeces). METHODS AND RESULTS: Both polar (flaA) and lateral (lafA) flagellin genes have been investigated by means of PCR and colony blot hybridization assays. The ability to form biofilm in polystyrene microtitre plates was evaluated and correlated with the presence and absence from these genes. The flaA and lafA genes had a frequency of 94% and 71%, respectively. All lafA(+) strains were also flaA(+) . Biofilm formation was observed in 72% of strains. Ninety-four per cent of flaA(+) lafA(+) strains could form biofilm and those that presented an intense biofilm production harboured both genes. All flaA(-) lafA(-) isolates, as well as 76% of flaA(+) lafA(-) strains, were incapable of forming biofilm. All the fish strains were flaA(+) lafA(+) and displayed higher biofilm formation (88%). Lagoon water samples exhibited lower positivity rate for the lafA gene (57%) and decreased ability to produce biofilm (39%). CONCLUSIONS: Both polar and lateral flagellar function contribute to biofilm formation in Aer. caviae strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides evidence for the association of both flagella with biofilm formation, a factor required for pathogenicity of Aer. caviae strains of varied sources, especially food and human.


Subject(s)
Aeromonas caviae/growth & development , Aeromonas caviae/genetics , Biofilms/growth & development , Flagellin/genetics , Flagellin/metabolism , Aeromonas caviae/pathogenicity , Bacterial Adhesion/genetics , Flagella/genetics , Flagella/metabolism , Genotype , Humans , Plastics
4.
Biochem Biophys Res Commun ; 382(1): 74-8, 2009 Apr 24.
Article in English | MEDLINE | ID: mdl-19254695

ABSTRACT

Leishmania (V.) braziliensis, the causative agent of mucocutaneous leishmaniasis in the New World, may present an LD1 type genomic amplification that appears as a small 245 kb linear chromosome, and is not clearly associated to the presence of a selection agent. A bt1 gene, codifying for a biopterin transporter protein, was identified in this small chromosome. Leishmania are auxotrophic for pterins and one of the proposed explanations for the appearance of this amplification is the improvement of biopterin capture by the parasite. We analyzed some biological aspects of two lineages of L. braziliensis strain M2903, with and without the small amplified chromosome. We showed differences in infectivity of these lineages, in macrophages and the insect vector Lutzomyia longipalpis, as well as in the uptake and metabolization of intermediates of the Leishmania biopterin salvage pathway. Our results suggest that the genomic amplification favors survival due to improved biopterin capture and at the same time hinders the infective capability, suggesting that within a population different parasites can perform different roles.


Subject(s)
Leishmania braziliensis/genetics , Leishmania braziliensis/pathogenicity , Leishmaniasis, Mucocutaneous/parasitology , Membrane Transport Proteins/genetics , Protozoan Proteins/genetics , Animals , Cell Line , Chromosomes/genetics , Gene Amplification , Insect Vectors/parasitology , Leishmania braziliensis/metabolism , Macrophages/parasitology , Methotrexate/pharmacology , Mice , Pteridines/metabolism
5.
J Neuroendocrinol ; 20(9): 1052-7, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18624930

ABSTRACT

The neurotensin (NT) produced in the hypothalamus and in pituitary gonadotrophs and thyrotrophs participates in neuroendocrine regulation. Recently, the involvement of this peptide in normal and neoplastic cell proliferation has been postulated. In the present study, we evaluated the expression of NT and its receptors (NTR1, 2 and 3) in a series of 50 pituitary adenomas [11 growth hormone (GH)-, eight prolactin (PRL)-, four adrenocorticotrophic hormone (ACTH)- and 27 nonfunctioning adenomas]. NT mRNA expression was significantly higher in functioning compared to nonfunctioning adenomas and with normal pituitary. Nonfunctioning pituitary adenomas showed lower expression of NT mRNA than normal pituitary. In the immunohistochemical study of functioning adenomas, NT was colocalised with GH, PRL and ACTH secreting cells. In nonfunctioning adenomas, the NT immunoreactivity intensity was variable among the samples. NTR3 mRNA expression was observed in all examined samples and was higher in the adenomas, both functioning and nonfunctioning, compared to normal pituitary. By contrast, NTR1 and NTR2 mRNA were not detected in either pituitary adenomas or normal tissue. The higher expression of NTR3, as well as the expression of NT by tumoural corticotrophs, lactotrophs and somatotrophs, which are cells types that do not express this peptide in the normal pituitary, suggests that NT autocrine and/or paracrine stimulation mediated by NTR3 may be a mechanism associated with the tumourigenesis of functioning adenomas.


Subject(s)
Adenoma/genetics , Neurotensin/genetics , Pituitary Neoplasms/genetics , Receptors, Neurotensin/genetics , Adenoma/metabolism , Adenoma/pathology , Adult , Aged , Autocrine Communication/genetics , Autocrine Communication/physiology , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Neurotensin/metabolism , Paracrine Communication/genetics , Paracrine Communication/physiology , Pituitary Neoplasms/metabolism , Pituitary Neoplasms/pathology , RNA, Messenger/metabolism , Receptors, Neurotensin/metabolism , Tumor Cells, Cultured , Young Adult
6.
J Anat ; 212(6): 817-26, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18510508

ABSTRACT

We have studied here the cellular distribution of several regulatory peptides in hormone-producing cells of the human pituitary during the fetal period. Immunohistochemistry was used to show the expression of several regulatory peptides, namely Angiotensin-II, Neurotensin and Galanin, at successive gestational stages and their co-localization with hormones in the human fetal adenohypophysis. Somatotrophs, gonadotrophs and thyrotrophs were differentiated earliest. At gestational week 9, Angiotensin-II immunoreactivity was co-localized only with growth hormone immunoreactivity in somatotrophs, one of the first hormone-producing cells to differentiate. This co-localization remained until week 37. Neurotensin immunoreactivity was present in gonadotrophs and thyrotrophs in week 23, after FSH and TSH hormone differentiation. Galanin immunoreactivity was present in all hormone-producing cell types except corticotrophs. The different pro-opiomelanocortin-derived peptides were detected at different stages of gestation and adrenocorticotrophic hormone immunoreaction was the last to be detected. Our results show an interesting relationship between regulatory peptides and hormones during human fetal development, which could imply that these peptides play a regulatory role in the development of pituitary function.


Subject(s)
Angiotensin II/analysis , Galanin/analysis , Neurotensin/analysis , Pituitary Gland, Anterior/embryology , Adrenocorticotropic Hormone/analysis , Cell Differentiation , Corticotrophs/chemistry , Gestational Age , Gonadotrophs/chemistry , Humans , Immunohistochemistry , Pituitary Gland, Anterior/chemistry , Somatotrophs/chemistry , Thyrotrophs/chemistry
7.
Anat Histol Embryol ; 37(4): 272-8, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18215203

ABSTRACT

A histological and immunochemical study of adenohypophysis development in two bird species: chicken (Gallus gallus) and Japanese quail (Coturnix coturnix japonica) was carried out, focussing firstly morphologically on the origin of its different lobes, then secondly on the differentiation of hormone-producing cells from the adenohypophysial anlage and their involvement in the differentiation of three calcium-binding proteins. The results of the morphological development study show how the origin of the adenohypophysis in chicken is totally ectodermic, whilst in Japanese quail the endoderm, in the form of Sessel's pouch, participates in forming the rostral zone of the anterior lobe. After studying the organogenesis and spatio/temporal differentiation of the hormone-producing cells proceeding from the adenohypophysial anlage, a regionalization model is proposed for the origin of the different lobes and cell types as well as time sequence, fundamentally the origin of cell regionalization in the adult adenohypophysis. In this process, at least in the two bird species studied, the results obtained from expressing the calcium-binding proteins, calbindin D 28K, calretinin and parvalbumin show a characteristic distribution pattern for each, suggesting distinct functions.


Subject(s)
Calcium-Binding Proteins/metabolism , Chick Embryo/embryology , Coturnix/embryology , Pituitary Gland, Anterior/embryology , Animals , Cell Differentiation , Gene Expression Regulation, Developmental , Pituitary Gland, Anterior/physiology
8.
Anat Histol Embryol ; 37(4): 263-71, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18215204

ABSTRACT

A developmental study of the adenohypophysis of the mouse was carried out in response to several as yet unanswered questions about its organogenesis and differentiation. The main objectives were to establish the origin of adenohypophysial lobes and cells from the Rathke's pouch (RP) and elucidate the mechanisms of development and functional differentiation of the gland. Using diverse techniques, the morphological development, proliferation and differentiation were studied in order to delimit different proliferative regions in the RP, and provide a satisfactory explanation for the distribution of each cell type in the adult gland. Combining the proliferation and differentiation studies, corticotropic and somatotropic cells appear to mainly originate from undifferentiated precursors located within each of these proliferative regions. The involvement of transcription factor Pitx 2 and calcium-binding protein Calbindin D 28K in the differentiation of corticotropic and somatotropic cells is further clarified.


Subject(s)
Homeodomain Proteins/metabolism , Organogenesis/physiology , Pituitary Gland, Anterior , S100 Calcium Binding Protein G/metabolism , Transcription Factors/metabolism , Animals , Biomarkers , Calbindin 1 , Calbindins , Cell Differentiation , Cell Proliferation , Female , Gene Expression Regulation, Developmental , Male , Mice , Pituitary Gland, Anterior/cytology , Pituitary Gland, Anterior/embryology , Pituitary Gland, Anterior/growth & development , Pituitary Gland, Anterior/metabolism , Homeobox Protein PITX2
9.
Vet Parasitol ; 150(1-2): 65-74, 2007 Nov 30.
Article in English | MEDLINE | ID: mdl-17905514

ABSTRACT

The purpose of the present study was the genetic characterization, sequencing and phylogenetic analysis of 18S rDNA sequences of Cryptosporidium isolates obtained from different animal hosts in Brazil. Fecal samples containing Cryptosporidium oocysts were obtained from chickens, ducks, quails, guinea pigs, dairy calves, dogs and cats. For amplification of 18S rDNA sequences the Secondary-PCR product of the extracted DNA from fecal suspension of each studied animal was utilized. The primary genetic characterization of Cryptosporidium sp. was performed using RFLP with the enzymes SspI and VspI. DNA samples were sequenced and subjected to phylogenetic analysis. The results showed C. baileyi infecting two ducks and one quail and C. melagridis infecting one chicken. The sequences obtained from Cryptosporidium sp. infecting guinea pigs were not identified within groups of known Cryptosporidium species. The isolates found parasitizing cats and one dog were diagnosed as C. felis and C. canis, respectively. One isolate of calf origin was identified as C. parvum. The phylogenetic analysis showed clear distribution of isolates between two Cryptosporidium sp. groups according to their gastric or intestinal parasitism. A great genetic distance was observed between C. felis and C. canis from Brazil when compared to the reference sequences obtained from GenBank. The results obtained during this study constitute the first report of rDNA sequences from C. baileyi, C. meleagridis, C. felis, C. canis and C. parvum isolated in Brazil.


Subject(s)
Animals, Domestic/parasitology , Cryptosporidium/classification , Cryptosporidium/genetics , Animals , Birds/parasitology , Brazil , Cryptosporidiosis/parasitology , Cryptosporidiosis/veterinary , Cryptosporidium/isolation & purification , DNA, Protozoan/genetics , Feces/parasitology , Genotype , Mammals/parasitology , Molecular Sequence Data , Phylogeny
10.
Histol Histopathol ; 22(7): 709-17, 2007 07.
Article in English | MEDLINE | ID: mdl-17455145

ABSTRACT

This study assesses the action of hypercortisolism on the hormone and peptide periadenoma region of removed ACTH-producing microadenoma. Our findings show that cortisol excess affects both ACTH and GH production, with no immunoreaction for these hormones. The remaining pituitary hormones (TSH, FSH and PRL) and POMC-derived peptides (betaEnd, alphaMSH and betaMSH) were not modified. Likewise, we observed pituitary immunoreactive cells for Neurotensin (NT), Intestinal vasoactive peptide (VIP), Substance P (SP) and Angiotensin-II (Ang-II). The colocalization demonstrated that NT was expressed in thyrotrope and gonadotrope cells, VIP in gonadotrope cells and SP in corticotrope cells. The results about Ang-II were inconclusive. On the other hand, immunoreaction for the NPY and Gal peptides were not present. In the adenomatous cells, the peptide NT is present in ACTH cells as well as SP. These results suggest a peptide regulation of pituitary cells in the pathological state that can differ between normal and tumoural cells of the same pituitary.


Subject(s)
ACTH-Secreting Pituitary Adenoma/chemistry , Adenoma/chemistry , Cushing Syndrome/etiology , Neuropeptides/analysis , Pituitary Hormones/analysis , ACTH-Secreting Pituitary Adenoma/complications , ACTH-Secreting Pituitary Adenoma/pathology , Adenoma/complications , Adenoma/pathology , Adrenocorticotropic Hormone/analysis , Adult , Angiotensin II/analysis , Corticotrophs/chemistry , Cushing Syndrome/metabolism , Cushing Syndrome/pathology , Female , Gonadotrophs/chemistry , Human Growth Hormone/analysis , Humans , Immunohistochemistry , Neurotensin/analysis , Substance P/analysis , Thyrotrophs/chemistry , Vasoactive Intestinal Peptide/analysis
11.
Neuroendocrinology ; 79(2): 90-9, 2004 Feb.
Article in English | MEDLINE | ID: mdl-15004431

ABSTRACT

Besides its potential roles as a central neuromodulator or a hypothalamic neurohormone, neurotensin (NT) may also have endocrine function in the anterior pituitary of mammals. We previously found that NT immunoreactivity is present in the secretory granules of gonadotropes and thyrotropes in both male and female rats, where its levels of expression are under the control of sex steroids. In this work, using immunocytochemistry and in situ hybridization, we have studied the postnatal development of NT-like immunoreactivity (NTir) and the mRNA encoding NT (mRNA-NT) in specific anterior pituitary cells of both male and female rats. NT expression starts after birth and displays an identical pattern in both sexes until sexual maturity, with mRNA-NT being detected from day 2 of postnatal life in thyrotropes localized in the central portion of the anterior lobe. This pattern of expression develops progressively throughout the 2nd and 3rd weeks in both sexes. By the beginning of the 3rd week, mRNA-NT can also be detected in gonadotropes localized in the periphery of the gland coinciding with a rise in serum estradiol concentrations in both sexes, and by day 21, mRNA-NT is extensively present in both the periphery and the central region. NTir is observed from days 5-6 in thyrotropes predominantly localized in the central portion of the anterior lobe, and by day 21, NTir is also detected in gonadotropes localized in the periphery of the gland. This pattern remains similar in both sexes until the time of puberty, when female rats start displaying plastic changes in NT expression according to the stage of the estrous cycle. These findings indicate that NT expression in the rat anterior pituitary is cell specific, and develops from birth to adulthood under the control of sex steroid hormones. In addition, preliminary data showing the presence of NT receptors in rat pituitary cells support the hypothesis of a paracrine or an autocrine role for this peptide within the pituitary.


Subject(s)
Aging/physiology , Gonadal Steroid Hormones/blood , Neurotensin/metabolism , Pituitary Gland, Anterior/metabolism , Sexual Maturation/physiology , Animals , Estradiol/blood , Female , Gene Expression Regulation, Developmental , Immunohistochemistry , In Situ Hybridization , Male , Neurotensin/genetics , Pituitary Gland, Anterior/cytology , Progesterone/blood , RNA, Messenger/analysis , Rats , Rats, Sprague-Dawley , Sex Characteristics , Testosterone/blood
12.
Neuroscience ; 103(4): 1025-31, 2001.
Article in English | MEDLINE | ID: mdl-11301209

ABSTRACT

The function of a particular neuronal population is in part determined by its neurotransmitter phenotype. We have found that a neuronal-derived septal cell line (SN56), known for its cholinergic properties, also synthesizes and releases luteinizing hormone-releasing hormone. In addition, these cells express the messenger RNAs encoding estrogen and progesterone receptors. The activation of these receptors by their respective ligands cooperatively modulates the depolarization-induced release of luteinizing hormone-releasing hormone in these cells. We have also found that a number of septal neurons in postnatal (1-week-old) mice are immunoreactive to both choline acetyltransferase and luteinizing hormone-releasing hormone. These results indicate that both neurotransmitters, acetylcholine and luteinizing hormone-releasing hormone, may co-exist in septal neurons of the CNS and that they could be modulated by gonadal hormones, and suggest that luteinizing hormone-releasing hormone could be involved in some of the actions of sex steroids on cholinergic neurotransmission.


Subject(s)
Choline O-Acetyltransferase/metabolism , Gonadal Steroid Hormones/physiology , Gonadotropin-Releasing Hormone/metabolism , Prosencephalon/metabolism , Animals , Animals, Newborn/metabolism , Cell Line , Electrophysiology , Estrogen Receptor alpha , Estrogen Receptor beta , Gonadotropin-Releasing Hormone/genetics , Immunohistochemistry , Mice , Neurons/metabolism , Prosencephalon/cytology , Prosencephalon/physiology , RNA, Messenger/metabolism , Receptors, Estrogen/genetics , Receptors, Progesterone/genetics , Reverse Transcriptase Polymerase Chain Reaction
13.
Cardiol Young ; 11(6): 609-13, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11813911

ABSTRACT

INTRODUCTION: The frequent occurrence of prenatal hypertrophy of the muscular ventricular septum has been widely reported in fetuses of diabetic mothers. OBJECTIVES: This experimental study was carried out to test the hypothesis that the weight of the heart, the ratio of the cardiac weight to that of the body, the thickness of the muscular ventricular septum, and the myocytic profile within the ventricular septum are all increased in fetuses of diabetic rats in comparison to fetuses of normal rats. METHODS: Diabetes was induced in 5 pregnant Wistar rats, bearing 30 fetuses, on the eighth day after conception, by intraperitoneal injection of 50 mg/kg of streptozotocin. Five normal pregnant Wistar rats, bearing 20 fetuses, made up the control group. Morphometric data were obtained by a computer-assisted method applied to the measurements of the thickness of the ventricular septum, and myocytic nuclear area. Statistical analysis utilized Student's t-test and Kruskal-Wallis test. RESULTS: The mean thickness of the septum was 675.56 microm (+/-159) in the control fetuses, and 904.39 microm (+/-262) in the fetuses carried by diabetic mothers (p < 0.001). The cardiac weight was 0.016 g (+/-0.004) in the control group, and 0.023 g (+/-0.005) in the group of diabetic fetuses (p < 0.001). The ratio of cardiac to body weight was 0.294% (+/-0.079) in the control group, and 0.514% (+/-0.073) in the diabetic group (p < 0.001). The myocytic nuclear area was 14.70 microm2 in the control group, and 21.43 microm2 in the diabetic group (p < 0.001). CONCLUSIONS: The presence of cellular and morphologic cardiac hypertrophy in fetuses of diabetic rats was demonstrated by the significant difference between the two groups for each analyzed feature.


Subject(s)
Cardiomegaly/etiology , Diabetes, Gestational/complications , Fetus/abnormalities , Myocardium/pathology , Animals , Blood Glucose/analysis , Disease Models, Animal , Female , Fetal Weight , Heart/growth & development , Liver/growth & development , Models, Cardiovascular , Organ Size , Pregnancy , Pregnancy in Diabetics/complications , Rats , Rats, Wistar , Statistics as Topic
14.
Dis Aquat Organ ; 42(3): 233-6, 2000 Sep 28.
Article in English | MEDLINE | ID: mdl-11104076

ABSTRACT

The effect of Clinostomum detruncatum metacercaria infection on the activities of the antioxidant enzymes superoxide dismutase and catalase in muscle of the freshwater fish Rhamdia quelen was analyzed. Tert-butyl hydroperoxide-initiated chemiluminescence, a measure of lipid peroxidation, was also investigated. Enzyme activities were similar in infected and uninfected fishes. However, the chemiluminescence was almost 2-fold higher in muscle of infected fishes than in muscle of uninfected ones. These results indicate that parasite infection induces oxidative stress and a higher level of membrane damage in the fish muscle due to an imbalance between pro-oxidants and non-enzymatic antioxidants. Our results suggest that fish response to parasite infection could involve, as in other vertebrates, reactive oxygen intermediates.


Subject(s)
Catfishes , Fish Diseases/parasitology , Lipid Peroxidation , Muscle, Skeletal/parasitology , Trematoda/pathogenicity , Trematode Infections/veterinary , Animals , Brazil , Catalase/analysis , Fish Diseases/pathology , Luminescent Measurements , Muscle, Skeletal/enzymology , Muscle, Skeletal/pathology , Oxidative Stress , Scintillation Counting/veterinary , Superoxide Dismutase/analysis , Trematode Infections/parasitology , Trematode Infections/pathology , tert-Butylhydroperoxide/chemistry
15.
Mem Inst Oswaldo Cruz ; 94(6): 795-802, 1999.
Article in English | MEDLINE | ID: mdl-10585658

ABSTRACT

The intestinal microbiota, a barrier to the establishment of pathogenic bacteria, is also an important reservoir of opportunistic pathogens. It plays a key role in the process of resistance-genes dissemination, commonly carried by specialized genetic elements, like plasmids, phages, and conjugative transposons. We obtained from strains of enterobacteria, isolated from faeces of newborns in a university hospital nursery, indication of phenotypical gentamicin resistance amplification (frequencies of 10(-3) to 10(-5), compatible with transposition frequencies). Southern blotting assays showed strong hybridization signals for both plasmidial and chromosomal regions in DNA extracted from variants selected at high gentamicin concentrations, using as a probe a labeled cloned insert containing aminoglycoside modifying enzyme (AME) gene sequence originated from a plasmid of a Klebsiella pneumoniae strain previously isolated in the same hospital. Further, we found indications of inactivation to other resistance genes in variants selected under similar conditions, as well as, indications of co-amplification of other AME markers (amikacin). Since the intestinal environment is a scenario of selective processes due to the therapeutic and prophylactic use of antimicrobial agents, the processes of amplification of low level antimicrobial resistance (not usually detected or sought by common methods used for antibiotic resistance surveillance) might compromise the effectiveness of antibiotic chemotherapy.


Subject(s)
Feces/microbiology , Gentamicins/pharmacology , Klebsiella pneumoniae/drug effects , Drug Resistance, Microbial/genetics , Gene Amplification , Hospitalization , Humans , Infant, Newborn , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/isolation & purification , Stem Cells
16.
J Neuroendocrinol ; 11(10): 785-94, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10520127

ABSTRACT

In addition to regulating anterior pituitary function by being released from the median eminence, mammalian neurotensin (NT) may also exert an autocrine or a paracrine action within the anterior pituitary. In this study, using double immunostaining with elution restaining, we identified the specific anterior pituitary cells which express NT immunoreactivity (NT-IR) during the rat oestrous cycle. In the normal cycling rat, NT-IR was present in both gonadotrophs and thyrotrophs and displayed plastic changes along the oestrous cycle. Both the number of TSH-NT positive cells and the intensity of immunological reaction were elevated during dioestrus, and decreased through pro-oestrus and early oestrus. NT-IR was also high in both follicle stimulating hormone (FSH)- or luteinizing hormone (LH)-positive cells during early pro-oestrus, and decreased during late pro-oestrus. Treatment of intact rats with either the anti-oestrogens Tamoxifen or LY117018, or the anti-progestagen RU486 prevented the normal expression of NT-IR in thyroid-stimulating hormone (TSH)-, FSH-, and LH-positive cells during pro-oestrus. Bilateral ovariectomy induced a dramatic reduction in the number of NT-IR cells. This effect was completely prevented by treatment of ovariectomized rats with oestradiol and progesterone, and was unaffected by the concurrent administration of a GnRH antagonist. Furthermore, administration of an anti-oestrogen together with an anti-progestagen to ovariectomized-oestrogen, progesterone-treated rats, blocked the stimulatory effect of ovarian hormones on NT-IR in anterior pituitary cells. These findings demonstrate that, in female rats, NT is specifically localized in gonadotrophs or thyrotrophs. In addition, they strongly suggest that changes in circulating concentrations of ovarian steroids may control both NT synthesis in, and release from, these cells.


Subject(s)
Estradiol/physiology , Gonadotropins, Pituitary/biosynthesis , Neurotensin/biosynthesis , Pituitary Gland, Anterior/metabolism , Progesterone/physiology , Thyrotropin/biosynthesis , Animals , Estrogen Receptor Modulators/pharmacology , Estrus/drug effects , Estrus/physiology , Female , Follicle Stimulating Hormone/metabolism , Gonadotropin-Releasing Hormone/antagonists & inhibitors , Immunohistochemistry , Luteinizing Hormone/metabolism , Ovariectomy , Pituitary Gland, Anterior/cytology , Pituitary Gland, Anterior/physiology , Progesterone/antagonists & inhibitors , Rats , Rats, Sprague-Dawley
17.
Proc Natl Acad Sci U S A ; 91(24): 11442-6, 1994 Nov 22.
Article in English | MEDLINE | ID: mdl-7972081

ABSTRACT

Trypanosomatid protozoans are pterin auxotrophs, a finding noted decades ago which heralded the discovery of key metabolic roles played by pteridines in eukaryotes. We have now identified the enzyme mediating unconjugated pteridine salvage in the human parasite Leishmania major, PTR1 (pteridine reductase 1, formerly hmtxr or ltdh). PTR1 is the gene in the amplified H region responsible for methotrexate (MTX) resistance, and belongs to a large family of oxidoreductases with diverse substrates and roles. We generated Leishmania lacking PTR1 by homologous gene targeting, and these ptr1- mutants required reduced biopterin (dihydro- or tetrahydrobiopterin) for growth. PTR1 purified from engineered Escherichia coli exhibited a MTX-sensitive, NADPH-dependent biopterin reductase activity. PTR1 showed good activity with folate and significant activity with dihydrofolate and dihydrobiopterin, but not with quinonoid dihydrobiopterin. PTR1 thus differs considerably from previously reported pteridine reductases of trypanosomatids and vertebrates. Pteridine reductase activity was diminished in ptr1- Leishmania and was elevated in transfected parasites bearing multiple copies of PTR1; correspondingly, ptr1- was MTX-hypersensitive whereas the multicopy transfectant was MTX-resistant. The concordance of the biochemical and genetic properties of PTR1 suggests that this is the primary enzyme mediating pteridine salvage. These findings suggest several possible mechanisms for PTR1-mediated MTX resistance and should aid in the design of rational chemotherapy.


Subject(s)
Genes, Protozoan , Leishmania major/metabolism , Oxidoreductases/genetics , Pteridines/metabolism , Animals , Base Sequence , Cloning, Molecular , DNA Primers/chemistry , Drug Resistance , Methotrexate/pharmacology , Molecular Sequence Data , Mutagenesis, Insertional
18.
J Comp Neurol ; 348(4): 511-30, 1994 Oct 22.
Article in English | MEDLINE | ID: mdl-7836560

ABSTRACT

The distribution of neurotensin (NT) was studied in the brain of three species belonging to the three major classes of cold-blooded vertebrates: teleost fishes (Carassius auratus), anuran amphibians (Hyla meridionalis), and reptiles (Gallotia galloti; Lacertidae). By using antibodies directed against synthetic bovine NT in the three species, immunoreactive cell bodies were discovered mostly in the telencephalon and diencephalon, in particular at the level of the preoptic region the mediobasal hypothalamus, and the thalamus. In the frog and the lizard, additional immunoreactive (ir) structures were observed in the optic tectum and the tegmentum of the mesencephalon. In the goldfish pituitary, an extensive innervation was consistently observed at the level of the rostral pars distalis, whereas in both frog and lizard, positive fibers were only detected in the external layer of the median eminence. In the three species there is a striking overlap between the distribution of the NT-ir cell bodies and that of the target cells for sexual steroids. The results are discussed in relation with those reported in birds and mammals, and with the possible interactions among NT, sexual steroids, and the neuroendocrine control of pituitary hormone release, in particular prolactin and gonadotrophin.


Subject(s)
Amphibians/metabolism , Brain Chemistry/physiology , Goldfish/metabolism , Neuropeptides/analysis , Neurotensin/analysis , Reptiles/metabolism , Amino Acid Sequence , Animals , Biological Evolution , Molecular Sequence Data
19.
Neurosci Lett ; 177(1-2): 131-4, 1994 Aug 15.
Article in English | MEDLINE | ID: mdl-7824164

ABSTRACT

The presence of tyrosine hydroxylase (TH) in the rat pineal gland was studied using a combination of immunochemical and biochemical methods. In superior cervical ganglionectomized (SCGx) animals and in isolated pineals incubated for 72 h, both TH immunoreactive (TH-IR) fibers and TH biochemical activity were still present but reduced. Conversely, in dispersed pinealocytes incubated for only 24 h we were unable to detect either TH activity or TH-positive cells. Since in the pineal gland of intact rats total 3-methoxy-4-hydroxy phenylglycol (MHPG) was undetectable, and only traces of norepinephrine (NE) were present in the pineal of ganglionectomized animals, the results suggest a central pinealopetal catecholaminergic pathway which could use dopamine as a neurotransmitter.


Subject(s)
Dopamine/physiology , Nerve Tissue Proteins/analysis , Pineal Gland/enzymology , Tyrosine 3-Monooxygenase/analysis , Animals , Dopamine/analysis , Male , Methoxyhydroxyphenylglycol/analysis , Norepinephrine/analysis , Pineal Gland/innervation , Rats , Rats, Sprague-Dawley , Superior Cervical Ganglion/physiology , Superior Cervical Ganglion/surgery , Sympathectomy
20.
Dev Neurosci ; 16(5-6): 260-6, 1994.
Article in English | MEDLINE | ID: mdl-7539360

ABSTRACT

A study was made on the development of cortical synapses in the gracile nucleus of rats using degeneration methods. A total of 46 animals, 1 adult and 45 neonates whose ages varied from 1 to 7 days, had the right somatosensory motor cortex destroyed. The survival period varied from 1 to 30 days. Identification of axonal terminals in the gracile nucleus was also achieved by tracing the cortical fibres of 1 adult rat using horseradish peroxidase-wheat germ agglutinin (HRP-WGA). Degenerating axodendritic and axosomatic terminals that originated from cortical fibres were seen in the adult animal which survived 2 days. Their origin was confirmed by the presence of HRP-WGA inside the terminals. Light or electron microscopic changes were not seen, and in particular, the gracile nucleus was not smaller than in the control adult animals which survived 30 days or in neonates which survived 8-30 days, consistent with the small component of cortifugal fibres believed to terminate in secondary sensory nuclei. In neonates that survived a shorter period, terminal degeneration was only seen in cases operated at 4 days and later, indicating that cortical axons do not synapse in the gracile nucleus until postnatal day 4. Our results provide further support for the existence of a period in which the fibres approach their target but do not penetrate it to form synaptic junctions during the growth of cortical axons toward their targets, since previous studies have demonstrated that cortical fibres persisting to adulthood decussate completely at the level of the medulla at 12-36 h after birth.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Cerebral Cortex/growth & development , Medulla Oblongata/growth & development , Nerve Fibers/physiology , Animals , Animals, Newborn , Cerebral Cortex/cytology , Horseradish Peroxidase , Medulla Oblongata/cytology , Medulla Oblongata/ultrastructure , Motor Cortex/physiology , Nerve Degeneration/physiology , Rats , Rats, Wistar , Somatosensory Cortex/physiology , Synapses/physiology , Tissue Fixation , Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate , Wheat Germ Agglutinins
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