RESUMEN
AIMS: Infectious spleen and kidney necrosis virus (ISKNV) has recently been recognized as a causative agent of serious systemic disease in tilapia. Our objective was to establish a new colorimetric loop-mediated isothermal amplification (LAMP) assay with pre-addition of hydroxynapthol blue (blue-LAMP) to investigate ISKNV transmission in tilapia. METHODS AND RESULTS: The blue-LAMP, targeting a major capsid protein gene of ISKNV, was conducted at 65°C for 45 min, allowing unaided visual detection of the pathogen based on colour change without cross-amplification of other known fish pathogens tested. Comparison of blue-LAMP and PCR assays revealed a higher detection level for blue-LAMP assay (41·33%) in a population of farmed tilapia infected with ISKNV. The investigation of ISKNV transmission pattern in farmed red tilapia using the blue-LAMP revealed a possible matroclinical form. The presence of ISKNV in the gonad samples was confirmed by in situ LAMP assay. Positive signals only appeared in ovarian follicles, and not in oocytes. Moreover, tissue tropism assay revealed that the brain was the main target organ in both farmed red tilapia (40%) and Nile tilapia (20%). CONCLUSIONS: The developed blue-LAMP assay has the potential to be used as a viable tool for screening covert and natural infections of ISKNV in tilapia. The evidence of vertical transmission of ISKNV infection in tilapia indicates the seriousness of this disease and will require a close attention and collaboration between tilapia hatcheries and disease experts in order to find a solution. SIGNIFICANCE AND IMPACT OF THE STUDY: The new blue-LAMP assay is a time-saving and economically viable detection tool, which allows unaided visual detection for ISKNV in tilapia, and it could be applicable for field applications. Evidence on the vertical transmission of ISKNV in farmed tilapia suggests a need for developing farm management practices to control the spread of virus in aquaculture industries.
Asunto(s)
Enfermedades de los Peces/virología , Técnicas de Amplificación de Ácido Nucleico , Infecciones por Retroviridae/veterinaria , Tilapia/virología , Animales , Acuicultura/métodos , Colorimetría/métodos , Enfermedades de los Peces/transmisión , Infecciones por Retroviridae/diagnóstico , Infecciones por Retroviridae/transmisión , Infecciones por Retroviridae/virología , Sensibilidad y Especificidad , Virus de la Necrosis Esplénica del Pato de Trager/genética , Virus de la Necrosis Esplénica del Pato de Trager/aislamiento & purificaciónRESUMEN
UNLABELLED: Streptococcus agalactiae and Strep. iniae are bacterial pathogens that cause streptococcosis in many fish species. An accelerated colorimetric loop-mediated isothermal amplification (LAMP) assay with pre-addition of calcein was established, and the transmission and detection of Strep. agalactiae and Strep. iniae in tilapia under natural aquatic environment were investigated. A positive reaction was observed by a colour change from orange to green through the naked eyes after completion at 63°C for 30 min with 10 times higher sensitivity than that of nested PCR assays and without cross-amplification with other fish bacterial pathogens. All sample types of Nile and red tilapia (broodstock, fertilized egg, fry) were Strep. agalactiae- and Strep. iniae positive by this new method, implying that they could be vertically transmitted. With its application for screening broodstock and fry before stocking and for monitoring fish health in grow-out ponds, the method would become very useful in fish farming industry. SIGNIFICANCE AND IMPACT OF THE STUDY: The application of colorimetric LAMP with pre-addition of calcein offers simple, rapid and sensitive technique with applicability for small field laboratories. This technique explored the possible vertical transmission mode of Strep. agalactiae and Strep. iniae under natural aquatic environment. It could be such preliminary data provided for the screening broodstock before breeding and/or the specific-pathogen-free production.
Asunto(s)
Colorimetría/métodos , Enfermedades de los Peces/microbiología , Técnicas de Amplificación de Ácido Nucleico/métodos , Infecciones Estreptocócicas/veterinaria , Streptococcus/aislamiento & purificación , Animales , Enfermedades de los Peces/diagnóstico , Infecciones Estreptocócicas/diagnóstico , Infecciones Estreptocócicas/microbiología , Streptococcus/genética , Streptococcus agalactiae/genética , Streptococcus agalactiae/aislamiento & purificación , Tilapia/microbiologíaRESUMEN
BACKGROUND AND AIM: Some degenerative diseases of the nervous system have been linked to hormonal imbalance in postmenopausal women. It is argued that young coconut juice (YCJ) could have some estrogen-like characteristics, but this is still debatable. Our aim was to investigate this argument, and to examine whether YCJ has any neuroprotective effects. MATERIALS AND METHODS: Four groups of female rats (10 in each group) were included in this study. These included sham-operated, overiectomized (ovx), ovx and receiving estradiol benzoate (EB) injections intraperitoneally, and ovx and receiving YCJ orally. At the end of the five-week study, the rats were sacrificed, and their serum estradiol (E2) level was measured by chemiluminescent immunoassay. Moreover, the rat brains were excised, and the cortical pyramidal neurons were examined using markers of neuronal cell death, namely anti-neurofilament (NF200) and anti-parvalbumin (PV) antibodies. RESULTS: Our results showed that the rat group which received YCJ had its serum E2 level significantly (P<0.05) higher than the ovx group which did not receive any treatment, and the sham-operated group. A similar trend was observed with the group which received EB injections, but no significant difference was present when the latter was compared with the sham-operated group. In addition, a significant reduction in neuronal cell death was observed in the YCJ-treated group, as compared to the ovx group which did not receive any treatment. This was indicated by the significantly (P<0.05) higher number of neurons which were immunopositive for NF200 and PV. Interestingly, the number of these neurons was also significantly (P<0.05) higher in the YCJ group, as compared to the EB group. CONCLUSION: This study confirms the argument that YCJ has estrogen-like characteristics, and it also adds more evidence to the observation that hormonal imbalance could induce some brain pathologies in females.
Asunto(s)
Encéfalo/efectos de los fármacos , Cocos/química , Fitoestrógenos/farmacología , Fitoterapia , Extractos Vegetales/farmacología , Animales , Encéfalo/metabolismo , Muerte Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Estradiol/sangre , Femenino , Frutas/química , Humanos , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica , Proteínas de Neurofilamentos/metabolismo , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Ovariectomía , Parvalbúminas/metabolismo , Posmenopausia , Ratas , Ratas WistarRESUMEN
A rapid and sensitive PCR-ELISA has been developed for detection of hepatopancreatic parvovirus (HPV) in Penaeus monodon. The specific primer set amplified 156 bp fragment and could detect as a little as 0.01 fg of purified HPV DNA which equivalent to three viral particles. No cross-reactivity was observed when nucleic acid templates from white spot syndrome virus, yellow-head virus, monodon baculovirus and shrimp were tested. The crude DNA simple prepared from hepatopancreas can be used as DNA template and provide a favorable result. Using this technique for detection of HPV infection in 87 carrier shrimps revealed the higher sensitivity and efficiency of detection when compared to histological examination and conventional PCR. Sixty-two percent infection was detected by PCR-ELISA from samples with HPV negative diagnosed by histological examination. Therefore, this sensitive and specific method is promisingly useful for early detection of HPV infection in broodstock, carriers and for ex situ application where large numbers of samples can be analyzed simultaneously.
Asunto(s)
Infecciones por Parvoviridae/virología , Parvoviridae/aislamiento & purificación , Penaeidae/virología , Reacción en Cadena de la Polimerasa/normas , Animales , Cartilla de ADN , ADN Viral/análisis , Sistema Digestivo/virología , Ensayo de Inmunoadsorción Enzimática , Parvoviridae/genética , Infecciones por Parvoviridae/diagnóstico , Infecciones por Parvoviridae/veterinaria , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y EspecificidadRESUMEN
N-acetyltransferase (NAT) and melatonin were determined in the optic lobe of the giant freshwater prawn Macrobrachium rosenbergii de Man. The prawns were divided into three groups: fast-growing "jumper" males; slow-growing "laggard" males; and females. Both NAT and melatonin levels in the jumper and laggard males were comparable, whereas those of the female were significantly lower. The results suggested a sexual dimorphism in the NAT and melatonin in the optic lobe of this species. It was also found that when one optic lobe was isolated, the level of NAT and melatonin in the contralateral optic lobe did not show a compensatory increase in either males or females. On the contrary, melatonin was suppressed in the remaining optic lobes in both sexes.
Asunto(s)
Arilamina N-Acetiltransferasa/análisis , Melatonina/análisis , Lóbulo Óptico de Animales no Mamíferos/química , Palaemonidae/química , Caracteres Sexuales , Análisis de Varianza , Animales , Femenino , Masculino , Lóbulo Óptico de Animales no Mamíferos/enzimología , Palaemonidae/enzimologíaRESUMEN
Commercial, intensive, earthen shrimp ponds (188) in southern Thailand were stocked with postlarvae (PL) of Penaeus monodon that had tested positive or negative for white-spot syndrome virus (WSSV) infection by polymerase chain reaction (PCR) assay. All the PL were grossly healthy. At 2 wk intervals after stocking, shrimp from each pond were examined for gross WSSV lesions and tested for WSSV by PCR. Shrimp from all the ponds stocked with WSSV-PCR-positive PL (Group 0, n = 43) eventually showed gross signs of white-spot disease (WSD) at an average of 40 d after stocking. Of the remaining ponds stocked with WSSV-PCR-negative PL (n = 145), some remained WSSV-PCR-negative throughout the study (Group 5, n = 52), while others (93) became WSSV-PCR-positive after stocking, during the first month (Group 1, n = 23), second month (Group 2, n = 40), third month (Group 3, n = 24), or fourth month (Group 4, n = 6). Crop failure was defined as a pond drain or forced harvest before 14 wk or 98 d of cultivation. For Group 0 the proportion of ponds failing was 0.953, while it was only 0.019 for Group 5. Thus, the relative risk of failure for Group 0 was approximately 50 times that of Group 5. The relative risk of failure for Group 0 was also 3 times that for ponds stocked with WSSV-PCR-negative PL. Obviously, not all WSSV outbreaks resulted in crop failure. Of the 93 ponds stocked with PCR-negative PL that later yielded WSSV-PCR-positive shrimp, 53% reached successful harvest. The study showed that PCR screening of PL and rejection of WSSV-positive batches before stocking could greatly improve the chances of a successful harvest.
Asunto(s)
Acuicultura , Virus ADN/aislamiento & purificación , Penaeidae/virología , Animales , Virus ADN/genética , ADN Viral/análisis , Larva/virología , Reacción en Cadena de la Polimerasa , Tailandia , Factores de TiempoRESUMEN
Hepatopancreatic parvovirus (HPV) causes disease in several species of penaeid shrimp. Heavy infections may result in poor growth and reduced production for shrimp farmers. From one southern Thai shrimp pond with a high prevalence of HPV infection, 790 shrimp were sampled randomly and the hepatopancreas (HP) removed. Most HP were preserved in liquid nitrogen. However, every 10th HP (79 total) was divided into 2 parts appropriately fixed for examination by transmission electron microscopy (TEM) and light microscopy. Based on light microscopy, the prevalence of HPV infection in the pond was approximately 30% and its presence was confirmed by TEM of parallel samples. The virus was subsequently purified from hepatopancreatic homogenates of the samples preserved in liquid nitrogen. Negative staining of the purified viral preparation revealed unenveloped, icosahedral viral particles 22 to 24 nm in diameter. Agarose gel electrophoresis of nucleic acid extracts revealed the presence of 2 fragments, one very intense (5.8 kb) and the other weak (4.2 kb). The larger fragment was degraded by DNase I and S1 nuclease, indicating single-stranded DNA (ssDNA) characteristic of the viral family Parvoviridae. The smaller fragment was degraded by DNase I but not by S1 nuclease, indicating that it comprised double-stranded DNA. A genomic DNA library of the 5.8 kb ssDNA was constructed in pUC18 and a clone containing a 659 bp fragment specific and sensitive for HPV was selected for sequencing. Based on this sequence, an HPV-specific primer set was designed to yield a 156 bp amplicon by polymerase chain reaction (PCR) amplification. The expected 156 bp amplicon was obtained only in the presence of HPV DNA template (at as little as 1 fg purified DNA) and not with nucleic acid templates extracted from healthy shrimp tissue or other shrimp pathogens. It is hoped that this PCR assay will be useful to shrimp aquaculturists for early detection and screening of shrimp larvae, parental broodstock or other possible carriers of HPV in the shrimp cultivation system.
Asunto(s)
ADN Viral/química , Parvovirus/aislamiento & purificación , Penaeidae/virología , Animales , Acuicultura , Secuencia de Bases , Southern Blotting , Clonación Molecular , Cartilla de ADN/química , Hibridación in Situ , Hígado/virología , Microscopía Electrónica , Datos de Secuencia Molecular , Páncreas/virología , Parvovirus/genética , Parvovirus/ultraestructura , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Análisis de Secuencia de ADN , TailandiaRESUMEN
White spot syndrome virus (WSSV) of the black tiger prawn Penaeus monodon is a recently discovered baculo-like virus disease which is currently the cause of very serious and widespread losses in the shrimp industry in Thailand and elsewhere in Asia. Three suspected crab carriers of this virus commonly found in shrimp-rearing areas were investigated. These were Sesarma sp., Scylla serrata and Uca pugilator. All these crabs could be infected with WSSV by injection and they sustained heavy viral infections for up to 45 d (confirmed by normal histology, specific in situ DNA hybridization and PCR amplification) without visible signs of disease or mortality. All of them also transferred the disease to P. monodon via water while physically separated in aquarium cohabitation tests. Transfer of the virus to the shrimp was monitored using in situ DNA hybridization and PCR assay at 12 h intervals after cohabitation began. With U. pugilator, WSSV could be detected in the shrimp cohabitants after 24 h using PCR amplification and after 60 h using in situ hybridization. With S. serrata, the shrimp were positive for WSSV after 36 h using PCR and after 60 h using DNA in situ hybridization. With Sesarma sp. they were positive after 48 h using PCR and 72 h using in situ hybridization. These laboratory studies demonstrated that crab carriers of WSSV may pose a real threat to cultivated shrimp. However, the studies were carried out in containers with a small volume and with relatively clean sea water as compared to shrimp cultivation ponds. Pond-based studies are now needed to determine whether factors such as pond volume, pond water quality and shrimp and crab behavior can influence the rate and success of transfer.
Asunto(s)
Braquiuros/virología , Penaeidae/virología , Animales , Acuicultura , Virus ADN , ADN Viral/análisis , Vectores de Enfermedades , Hemolinfa/virología , Hibridación in Situ/veterinaria , Reacción en Cadena de la Polimerasa , Síndrome , TailandiaRESUMEN
The effect of melatonin administration on nerve growth factor (NGF) was studied in the submandibular glands of adult Swiss male mice. Melatonin injection, at 1 microg daily for 30 days, resulted in an increase in the NGF content as detected by immunohistochemistry. The submandibular gland weight and the area of the granular convoluted tubules, which contained NGF, were also increased significantly. These effects were not observed when the dose of melatonin was increased to 10 and 50 microg daily. None of the melatonin treatments used influenced the weights or histology of the testes or seminal vesicles of the mice. The results suggest that melatonin, at physiological concentrations, directly regulates NGF synthesis in the mouse submandibular gland.
Asunto(s)
Melatonina/farmacología , Factores de Crecimiento Nervioso/metabolismo , Glándula Submandibular/efectos de los fármacos , Glándula Submandibular/metabolismo , Animales , Técnicas para Inmunoenzimas , Masculino , Ratones , Tamaño de los Órganos/efectos de los fármacos , Glándula Submandibular/citologíaRESUMEN
The activities of the enzymes N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) and the hormone melatonin were studied in the optic lobe of the subadult giant tiger shrimp Penaeus monodon. Compared with the level in other species, a relatively high level of NAT activity that was temperature- and pH-dependent were observed. The NAT enzyme had a relatively high maximum velocity (Vmax, 100 pmol/hr/micrograms protein) and low Michaelis constant (Km, 22 microM), when tryptamine is used as substrate. In contrast to the high level of NAT activity, HIOMT activity and melatonin levels were low in the optic lobe of the giant tiger shrimp. Sex differences in the levels of NAT activity and melatonin, which are observed in a freshwater species Macrobrachium rosenbergii, were not noticeable in the saltwater species P. monodon, at least not when they were in their subadult stage.
Asunto(s)
Acetilserotonina O-Metiltransferasa/análisis , Arilamina N-Acetiltransferasa/análisis , Melatonina/análisis , Lóbulo Óptico de Animales no Mamíferos/química , Animales , PenaeidaeRESUMEN
Giant freshwater prawns, Macrobrachium rosenbergii de Man, were reared under three different lighting conditions: continuous darkness (DD), 12 hr of light and 12 hr of darkness (LD 12:12) and continuous light (LL). After one month, the prawns were sacrificed and optic lobes isolated from the eyestalks were determined for N-acetyltransferase (NAT) activities and melatonin concentrations. Gonads were weighed and examined under light microscopy. The optic lobes from LL prawns contained significantly higher activities of NAT than those from LD 12:12 prawns. The melatonin concentrations and size and histological features of the gonads from the three groups of prawns did not differ. The results indicate that continuous light increases NAT activities in the optic lobe of M. rosenbergii but has no drastic effect on gonadal growth.
Asunto(s)
Arilamina N-Acetiltransferasa/metabolismo , Luz , Palaemonidae/enzimología , Animales , Oscuridad , Femenino , Gónadas/anatomía & histología , Gónadas/enzimología , Masculino , Melatonina/metabolismo , Lóbulo Óptico de Animales no Mamíferos/enzimología , Tamaño de los Órganos , PeriodicidadRESUMEN
The presence of adenosine and its receptors in the pineal gland suggests that they could have a regulatory influence on pineal physiology. Rat pineal glands cultured in the presence of the adenosine analog 5'-N-ethylcarboxamido adenosine (NECA) promoted a significant increase in pineal adenosine 3'5'-monophosphate (cAMP) content, similar to that caused by the beta-adrenergic receptor agonist isoproterenol (ISO). A potentiation of the cAMP response occurred when the glands were simultaneously stimulated with both NECA and ISO. Whereas high cAMP levels induced by ISO were associated with an increased N-acetyltransferase (NAT) activity and rise in the melatonin production and release, the NECA-induced rise in cAMP concentration failed to promote an increase in the activity of either NAT or another pineal enzyme thyroxine 5'-deiodinase type II; likewise, pineal melatonin levels did not rise.
Asunto(s)
Adenosina/análogos & derivados , Arilamina N-Acetiltransferasa/metabolismo , AMP Cíclico/metabolismo , Yoduro Peroxidasa/metabolismo , Melatonina/biosíntesis , Glándula Pineal/efectos de los fármacos , Vasodilatadores/farmacología , Adenosina/farmacología , Adenosina-5'-(N-etilcarboxamida) , Análisis de Varianza , Animales , Medios de Cultivo , Isoproterenol/farmacología , Masculino , Técnicas de Cultivo de Órganos , Glándula Pineal/enzimología , Radioinmunoensayo , Ratas , Ratas EndogámicasRESUMEN
Membrane preparation from the optic lobe of the giant freshwater prawn, Macrobrachium rosenbergii de Man, was examined for the presence of specific L-(3H) glutamate binding. The optic lobes were isolated from live animals. The tissue was homogenized and the membrane fraction isolated by differential centrifugation. The membrane suspension was incubated with 10-1,000 nM of L-(3H) glutamate at 37 degrees C for 60 min. Nonspecific binding was determined by incubating the mixture with 100 microM L-glutamate. L-(3H) glutamate specifically bound to the membrane fraction with a dissociation equilibrium constant (Kd) of 205 nM and maximum number of binding sites (Bmax) of 2.04 n mol/mg protein. By using LIGAND computerized program, the saturation isotherm binding pattern indicates a single type of binding. To determine the type of glutamate receptors, competitive inhibition and IC50 of several glutamate agonists and antagonists were determined. The study reveals a metabotropic type of binding site.
Asunto(s)
Glutamatos/metabolismo , Lóbulo Óptico de Animales no Mamíferos/metabolismo , Palaemonidae/metabolismo , Animales , Unión Competitiva , Calcio/farmacología , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Antagonistas de Aminoácidos Excitadores , Ácido Glutámico , Proteínas de la Membrana/metabolismo , Lóbulo Óptico de Animales no Mamíferos/efectos de los fármacosRESUMEN
1. Interferon-gamma (IFN-gamma) has been shown to suppress N-acetyltransferase (NAT) activity in cultured rat pineal glands when stimulated with isoproterenol (ISO). 2. Conversely, IFN-gamma has also been shown to increase the melatonin content of the rat pineal gland in organ culture. 3. Circumstantial evidence leads to a hypothesis that the NAT suppressive effect may be due to the action of IFN-gamma on the sympathetic nerve terminals. 4. To test this hypothesis, pineal glands from intact (INT) and superior cervical ganglionectomized (SCGX) rats, which had been operated 5 days earlier, were cultured with either ISO or ISO + IFN-gamma. 5. The concentration of ISO was 10(-8) M and that of IFN-gamma was 300 antiviral units/ml. 6. The pineals were incubated for a total period of 5.5 hr, after which the activities of NAT and hydroxyindole-O-methyltransferase (HIOMT) and the levels of melatonin and cAMP were estimated. 7. Suppression of NAT by IFN-gamma was observed in the pineals from INT rats, but not in those from SCGX animals. 8. IFN-gamma significantly enhanced melatonin levels over those in ISO-stimulated pineals and culture media from the SCGX animals, but not from the INT animals. 9. IFN-gamma treatment had no effect on either the HIOMT activity or cAMP levels. 10. The results indicate that the IFN-gamma-induced NAT suppression requires the integrity of the sympathetic nerve terminals and the IFN-gamma-induced enhancement of melatonin production is accomplished through its direct action on pinealocytes.
Asunto(s)
Interferón gamma/fisiología , Glándula Pineal/metabolismo , Sistema Nervioso Simpático/metabolismo , Acetilserotonina O-Metiltransferasa/metabolismo , Análisis de Varianza , Animales , Arilamina N-Acetiltransferasa/metabolismo , AMP Cíclico/metabolismo , Masculino , Técnicas de Cultivo de Órganos , Glándula Pineal/citología , Ratas , Ratas EndogámicasRESUMEN
The purpose of this study was to examine the effects of chronic administration of sublethal doses of carbaryl on pineal melatonin synthesis. N-methyl 1-naphthylcarbamate (carbaryl) (8.33 mg/kg B.W. daily) was administered orally to adult male albino rats for 6 successive days. Nocturnal (0100) N-acetyltransferase and hydroxyindole-O-methyltransferase activities were increased (roughly 75% and 60%, respectively) by carbaryl administration; likewise, carbaryl augmented serum melatonin levels at 2300. Pineal tryptophan. 5-hydroxytryptophan, serotonin, and 5-hydroxindole acetic acid levels were unaffected at all three time points. The results indicate that the carbamate pesticide, i.e., carbaryl, modifies pineal melatonin synthesis in vivo.
Asunto(s)
Acetilserotonina O-Metiltransferasa/metabolismo , Arilamina N-Acetiltransferasa/metabolismo , Carbaril/toxicidad , Melatonina/sangre , Glándula Pineal/efectos de los fármacos , 5-Hidroxitriptófano/metabolismo , Administración Oral , Animales , Carbaril/administración & dosificación , Ácido Hidroxiindolacético/metabolismo , Masculino , Glándula Pineal/enzimología , Radioinmunoensayo , Ratas , Serotonina/metabolismo , Estadística como Asunto , Triptófano/metabolismoRESUMEN
The effect of interferon-gamma (IFN-gamma) on melatonin production was determined in rat pineal glands in organ culture. IFN-gamma enhanced the production of melatonin in the glands incubated with either 10 nM or 1,000 nM isoproterenol (ISO, a beta-adrenergic receptor agonist) but decreased the 100 nM ISO response. The enhanced melatonin production was accompanied by either unchanged or a lower level of N-acetyltransferase (NAT) activity, whereas the suppression was accompanied by a reduced NAT activity. IFN-gamma did not change the activity of the enzyme hydroxyindole-O-methyltransferase (HIOMT) in the ISO-stimulated pineal glands. The results indicate that IFN-gamma has a dual action on the pineal gland: One is to increase melatonin production through yet unknown mechanisms, and the other is to suppress NAT activity. These results also suggest that the pineal gland, under physiological stimulation, is modulated by IFN-gamma to increase melatonin production. A hypothetical model is proposed to explain the delicate regulation of pineal function by the immune system.
Asunto(s)
Interferón gamma/farmacología , Melatonina/biosíntesis , Glándula Pineal/efectos de los fármacos , Acetilserotonina O-Metiltransferasa/metabolismo , Animales , Arilamina N-Acetiltransferasa/metabolismo , Isoproterenol/farmacología , Masculino , Técnicas de Cultivo de Órganos , Glándula Pineal/metabolismo , Ratas , Ratas Endogámicas , Proteínas RecombinantesRESUMEN
The effect of organochlorine insecticides lindane (1,2,3,4,5,6-hexachlorocyclohexane) and DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) were studied in terms of their effects on the rat pineal N-acetyltransferase (NAT) activity, hydroxyindole-O-methyltransferase (HIOMT) activity and pineal and serum melatonin levels during the day (2000h) and at night (2300 and 0100h). Additionally, pineal levels of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindole acetic acid (5-HIAA) were estimated. Nocturnal NAT activity was increased after lindane administration; likewise, lindane augmented pineal and serum melatonin levels at 2300h. Conversely, DDT was without a statistically significant effect on either NAT activity or on pineal or serum melatonin levels. Neither lindane nor DDT significantly influenced pineal HIOMT values either during the day or at night. Likewise, neither insecticide consistently influenced pineal levels of either 5-HTP, 5-HT or 5-HIAA. The results indicate that the organochlorine insecticide, lindane, modifies pineal melatonin synthesis in vivo.
Asunto(s)
Acetiltransferasas/metabolismo , Arilamina N-Acetiltransferasa/metabolismo , Ritmo Circadiano/efectos de los fármacos , DDT/farmacología , Hexaclorociclohexano/farmacología , Melatonina/metabolismo , Glándula Pineal/metabolismo , 5-Hidroxitriptófano/metabolismo , Acetilserotonina O-Metiltransferasa/metabolismo , Animales , Ácido Hidroxiindolacético/metabolismo , Masculino , Melatonina/sangre , Glándula Pineal/efectos de los fármacos , Ratas , Serotonina/metabolismoRESUMEN
The effect of photoperiod on growth of juvenile giant freshwater prawns, Macrobrachium rosenbergii de Man, was tested. The prawns were divided into four groups and each group was reared under one of the following light-dark conditions: continuous darkness (L0:D24), 12 hr light: 12 hr dark (L12:D12), 16 hr light: 8 hr dark (L16:D8), and 20 hr light: 4 hr dark (L20:D4). Body size was determined at the age of 45, 75, and 110 days by measuring total length, orbital length, and carapace length; body weight was determined at the age of 110 days. At 110 days of age, the prawns reared under L0:D24 photoperiod were significantly longer and heavier than those reared under other light-dark conditions. The survival rate of the prawns reared under L0:D24 photoperiod was also higher than that of other groups. This study indicates a positive effect of continuous darkness on growth and survival rate of juvenile giant freshwater prawns, M. rosenbergii.
Asunto(s)
Ritmo Circadiano/fisiología , Oscuridad , Palaemonidae/crecimiento & desarrollo , Animales , Ecdisteroides , Glándulas Endocrinas/fisiología , Hormonas de Invertebrados/fisiología , Palaemonidae/fisiologíaRESUMEN
The purpose of this study was to test the effects of recombinant rat interferon-gamma (IFN-gamma) on rat pineal function in organ culture. The glands were pre-incubated with IFN-gamma (50, 100, and 1,000 antiviral units/ml) for two hours, followed by a stimulation with isoproterenol (ISO, 10(-6) M) (in the presence of IFN-gamma) for an additional three hours. The effect of IFN-gamma alone on the pineal function was also tested by adding another group incubated with IFN-gamma (1,000 antiviral units/ml) without ISO stimulation. The following parameters were estimated at the end of the incubation: the activities of N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), the levels of melatonin, 5-hydroxytryptophan (5HTP), 5-hydroxytryptamine (5HT), and 5-hydroxyindole acetic acid (5HIAA), and the 5HT/5HIAA ratio. IFN-gamma had no effect on either NAT or HIOMT activities in the pineal glands. At 50 units/ml, IFN-gamma increased the melatonin content over the ISO-stimulated level in the pineal but not in the media. IFN-gamma alone, at 1,000 units/ml, also increased the melatonin content significantly over the control level. The levels of 5HTP and 5HIAA were significantly suppressed by IFN-gamma, either alone or in combination with ISO. The level of 5HT was not altered by any of the treatments. The 5HT/5HIAA ratio was significantly increased by IFN-gamma, either when given alone or when given in combination with ISO. The results suggest that IFN-gamma enhances melatonin production in the pineal gland by suppressing the oxidative deamination of 5HT to 5HIAA and shunting the biosynthetic pathway toward melatonin production.
Asunto(s)
Indoles/metabolismo , Interferón gamma/farmacología , Glándula Pineal/metabolismo , 5-Hidroxitriptófano/metabolismo , Acetilserotonina O-Metiltransferasa/metabolismo , Acetiltransferasas/metabolismo , Análisis de Varianza , Animales , Ácido Hidroxiindolacético/metabolismo , Isoproterenol/farmacología , Masculino , Melatonina/biosíntesis , Técnicas de Cultivo de Órganos , Glándula Pineal/efectos de los fármacos , Ratas , Ratas Endogámicas , Proteínas Recombinantes , Serotonina/metabolismoRESUMEN
Effects of melatonin on the ventral prostate of castrated rats supplemented with testosterone were studied using light microscopy. Stereological measurements were made of volume fractions of acini and stroma and surface fractions of glandular epithelium. From these figures and the weights of the glands, the volumes and surface areas were calculated, as well as the mean epithelial heights, mean acinar diameters, and mean distances between glandular acini. Doses of melatonin were varied, to verify its physiological and pharmacological effects. Castration without hormonal treatments produced atrophic changes, with decreases in acinar and stromal volume and widenings in the mean distances between the acini. None of these measurements differed among intact controls, sham-operated controls, and testosterone-supplemented castrated rats. In the castrated rats receiving both testosterone and melatonin, however, there were changes according to the doses of melatonin given. The animals receiving low doses of melatonin (50 and 400 micrograms daily) showed significant decreases in the volumes of the stroma and epithelium and the height of the epithelium. These stereological changes occurred without a significant reduction in the prostatic weights. The animals receiving the higher dose (800 micrograms daily) of melatonin showed no difference in any measurement compared with those of the testosterone-supplemented castrated rats. In rats receiving 2,000 micrograms of melatonin daily, there were significant reductions in the weights of the prostates and the volumes of the acini. These results suggest a direct action of melatonin on the ventral prostate, and the effects depend on the dose given.