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1.
J Invertebr Pathol ; 174: 107436, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32619548

RESUMEN

Several isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitacae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitacae) have been investigated as possible microbial control agents of key citrus pests in South Africa. Although laboratory results have been promising, field trials against foliar pests have shown limited success. These findings highlighted the need to investigate other biological attributes of these fungal isolates besides virulence in order to select candidates that may be better suited for the foliar environment. Thus, this study investigated the influence of temperature on the in vitro growth of seven indigenous local isolates and the humidity requirements necessary to promote successful infection, in comparison with two commercial isolates (B. bassiana PPRI 5339 and M. anisopliae ICIPE 69). All the fungal isolates grew across a range of temperatures (8-34 °C) and optimally between 26 and 28 °C. Similarly, fungal infection of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) fifth instars occurred across a range of humidity levels (12%, 43%, 75%, 98%) regardless of fungal concentration, although external sporulation was restricted to treatments exposed to 98% relative humidity. It was concluded that neither temperature nor humidity, when considered alone, is likely to significantly influence the efficacy of any of the isolates in the field, given that they are active within temperature and humidity ranges experienced in South African citrus orchards.


Asunto(s)
Beauveria/fisiología , Humedad , Metarhizium/fisiología , Mariposas Nocturnas/microbiología , Control Biológico de Vectores , Temperatura , Animales , Beauveria/patogenicidad , Citrus/crecimiento & desarrollo , Larva/crecimiento & desarrollo , Larva/microbiología , Metarhizium/patogenicidad , Mariposas Nocturnas/crecimiento & desarrollo , Sudáfrica , Virulencia
2.
Fungal Biol ; 124(5): 304-310, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32389292

RESUMEN

Seven indigenous entomopathogenic fungal isolates were identified as promising biocontrol agents of key citrus pests including false codling moth, Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), citrus thrips, Scirtothrips aurantii Faure (Thysanoptera: Thripidae) and citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae) under laboratory conditions. Even though field trials using the two most virulent isolates (Beauveria bassiana G Ar 17 B3 and Metarhizium anisopliae FCM Ar 23 B3) against soil-dwelling life stages of T. leucotreta were positive, foliar application against citrus mealybugs and thrips, has been disappointing. Thus, the UV sensitivity of the seven initial promising isolates (four B. bassiana and three M. anisopliae) in comparison with two commercial isolates (M. anisopliae ICIPE 69 and B. bassiana PPRI 5339) and their formulated products were investigated in this study. All isolates investigated were highly sensitive to UV radiation, and a 2 h exposure to simulated full-spectrum solar radiation at 0.3 W/m2 killed conidia of all tested isolates. Nonetheless, variability in susceptibility was found amongst isolates after exposure for 1 h. The most virulent M. anisopliae isolate, FCM Ar 23 B3, was the most susceptible to UV radiation with <3 % relative germination, 48-51 h post-exposure. Whilst isolates of the two mycoinsecticides showed similar susceptibility to UV radiation, their formulated products (vegetable oil and emulsifiable concentrate) were tolerant, when tested for 1 h. These findings indicate that a suitable UV protectant formulation of these fungi or a different application strategy will be required for success against P. citri and S. aurantii.


Asunto(s)
Beauveria , Metarhizium , Rayos Ultravioleta , Animales , Beauveria/efectos de la radiación , Agentes de Control Biológico/efectos de la radiación , Citrus/microbiología , Metarhizium/efectos de la radiación
3.
Arch Virol ; 161(10): 2917-20, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27456426

RESUMEN

The complete genomes of two novel South African betabaculovirus isolates, namely Phthorimaea operculella granulovirus (PhopGV-SA) and Plutella xylostella granulovirus (PlxyGV-SA), were sequenced and compared to the respective reference isolates PhopGV-1346 and PlxyGV-K1. For both isolates, the genome size and guanine-cytosine (GC) content were similar to those of the respective reference genomes. However, numerous-single nucleotide polymorphisms (SNPs) and several insertions/deletions were observed, revealing the novelty of the isolates. Focus was placed on analysing the observed insertion/deletion events by conducting amino acid sequence alignments for all ORFs of each isolate against all respective ORFs in the corresponding reference isolate. Certain ORFs in each granulovirus genome contained significant insertion/deletion events. In addition, the PlxyGV-SA genome had single-nucleotide insertions/deletions in ORFs 38 and 49 that resulted in the extension and complete overlap of these two ORFs with the neighbouring ORFs 39 and 48, respectively. These novel isolates have significant potential for development and application as biopesticides in South Africa, and the genetic variations observed may have important implications for the biological activity and management of host resistance in the field.


Asunto(s)
ADN Viral/química , ADN Viral/genética , Genoma Viral , Granulovirus/clasificación , Granulovirus/genética , Composición de Base , Variación Genética , Mutación INDEL , Sistemas de Lectura Abierta , Polimorfismo de Nucleótido Simple , Alineación de Secuencia , Análisis de Secuencia de ADN , Sudáfrica
4.
J Econ Entomol ; 109(4): 1578-85, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27341886

RESUMEN

Some of South Africa's citrus export markets require mandatory postharvest cold treatment of citrus fruit as a phytosanitary risk mitigation treatment for Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). An alternative to this may be partial cold treatment as one of the final steps in a systems approach to mitigate phytosanitary risk. Consequently, the efficacy of such partial cold treatments was evaluated. It was first determined that a 2°C cold treatment was significantly more effective against fourth and fifth instars (the most cold-tolerant instars) than treatments at 3°C and 4°C for a duration of 18 d. Secondly, it was determined that 2°C for 18 d and 1°C for 16 d were similarly effective, but both treatments were significantly more effective than 1°C for 14 d. Mean mortality of fourth and fifth instars treated with 2°C for 18 d in seven replicates from four trials was 99.94%. Finally, it was determined that the inability of the majority of surviving larvae to develop to adulthood would further increase the efficacy of a 2°C for 18 d treatment to 99.96%. Inclusion of reproductive nonviability of survivors increased mortality to 99.99%.


Asunto(s)
Citrus/fisiología , Control de Insectos/métodos , Mariposas Nocturnas/fisiología , Control Biológico de Vectores/métodos , Animales , Frutas/fisiología , Larva/crecimiento & desarrollo , Larva/fisiología , Mariposas Nocturnas/crecimiento & desarrollo , Sudáfrica , Análisis de Sistemas
5.
J Econ Entomol ; 109(4): 1564-70, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27341887

RESUMEN

A systems approach has been developed for mitigation of risk associated with Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), in citrus fruit exported from South Africa, as an alternative to a stand-alone cold treatment. This study was undertaken to assess compliance with inspection standards applicable to various steps within the systems approach and to determine its overall efficacy. Larval infestation of fruit was monitored weekly in fruit from 33 orchards, until the time of harvest, postpicking, and postpacking into export cartons. Significant positive regressions were recorded between infestation of fruit during the full monitoring period in the orchard and the last 4 wk before harvest, between the last 4 wk before harvest and on delivery to the packinghouse, and on delivery to the packinghouse and in the packed carton. There was an improvement in the level of compliance with each of these successive steps in the system, thus verifying that the grading and inspection thresholds were appropriately sensitive and confirmed the effectiveness of the system. The overall risk mitigation efficacy of the systems approach was calculated. The calculation included several known compounding under estimations of efficacy. Nonetheless, the proportion of fruit that could be infested with T. leucotreta after application of the systems approach was between P ≤ 5.328 × 10(-6) and P ≤ 8.380 × 10(-7), 6-38 times less than the proportion associated with the probit 9 (P ≤ 3.2 × 10(-5)) standard for a stand-alone cold treatment, being three survivors in 100,000 at the 95% confidence level.


Asunto(s)
Citrus/crecimiento & desarrollo , Mariposas Nocturnas , Control Biológico de Vectores/normas , Animales , Comercio , Frutas/crecimiento & desarrollo , Larva/crecimiento & desarrollo , Mariposas Nocturnas/crecimiento & desarrollo , Sudáfrica , Análisis de Sistemas
6.
J Econ Entomol ; 109(4): 1571-7, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27341890

RESUMEN

Some of South Africa's export markets require postharvest cold treatment of citrus fruit for phytosanitary risk mitigation for Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). An alternative to a standalone cold treatment may be a reduced intensity cold treatment as a step in a systems approach. For cold treatment trials, large numbers of larvae are required. Due to recent dramatic improvement of T. leucotreta control in the field, sufficient naturally infested citrus fruit are no longer available. Artificial infestation of fruit is not viable due to rapid decay of the fruit. Consequently, it is necessary to use laboratory-reared T. leucotreta larvae in artificial diet. In trials, field-collected larvae from the Eastern Cape were at least as cold-tolerant as those from other regions. Larvae in Navel oranges showed the median level of susceptibility in a range of citrus types evaluated at 6°C, and their use in trials was considered acceptable due to their greater natural susceptibility to T. leucotreta infestation. We demonstrated that larvae at high density in artificial diet were at least as cold-tolerant as larvae at lower densities. When exposed to 2°C for 18 d or longer, larvae in artificial diet as used in the trials were at least as cold-tolerant as larvae in fruit. Very few surviving larvae from fruit completed development, with no subsequent generation. Consequently, it is considered justifiable to conduct cold-treatment trials with laboratory-reared T. leucotreta larvae in artificial diet without risk of overestimating the effect of cold on feral larvae in citrus fruit. [corrected]


Asunto(s)
Citrus/fisiología , Control de Insectos/métodos , Mariposas Nocturnas/fisiología , Control Biológico de Vectores/métodos , Animales , Frutas/fisiología , Larva/crecimiento & desarrollo , Larva/fisiología , Mariposas Nocturnas/crecimiento & desarrollo , Sudáfrica
7.
J Econ Entomol ; 108(6): 2610-9, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26318002

RESUMEN

The effect of cold immobilization and long-distance transport of irradiated Thaumatotibia leucotreta (Meyrick) on the flight ability of male (♂) and female (♀) moths, the longevity of male and female moths, and the realized fecundity of mating pairs CIM (chilled irradiated moths) ♀ × CIM♂, CIM♀ × NIP (nonirradiated pupae) ♂, NIP♀ × CIM♂, and NIP♀ × NIP♂ was examined to improve application of the sterile insect technique (SIT). Adult moths treated with 150 Gy of gamma radiation were immobilized with cold temperature between 4 and 6°C inside a polyurethane cooler box and transported for 12 h by road from Citrusdal, Western Cape Province, to Addo, Eastern Cape Province. Nonirradiated moths were transported as pupae inside a cardboard tray and removed by hand after which male and female pupae were separated and placed inside containers for eclosion. Male and female moths were individually placed inside petri dishes to determine longevity or paired with irradiated and nonirradiated counterparts to evaluate realized fecundity before incubation in 100% darkness at 25°C and 75% relative humidity. Flight tests were conducted indoors at 25°C by release of individual moths per hand. A significant decrease in flight ability and longevity of irradiated false codling moth was found after handling, cold immobilization, and transport, although critically, realized fecundity was not affected. Because of the impact of long-distance transport on quality of the released insects as well as the efficacy of SIT, comprehensive protocols for this critical step in the process need to be developed for a pestiferous insect with phytosanitary status such as false codling moth.


Asunto(s)
Aptitud Genética , Mariposas Nocturnas , Control Biológico de Vectores , Transportes , Animales , Frío , Femenino , Fertilidad , Vuelo Animal , Longevidad , Masculino
8.
Neuroscience ; 171(4): 1265-72, 2010 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-20951774

RESUMEN

Inheritance of the APOE4 allele is a well established genetic risk factor linked to the development of late onset Alzheimer's disease. As the major lipid transport protein in the central nervous system, apolipoprotein (apo) E plays an important role in the assembly and maintenance of synaptic connections. Our previous work showed that 7 month old human apoE4 targeted replacement (TR) mice displayed significant synaptic deficits in the principal neurons of the lateral amygdala, a region that is critical for memory formation and also one of the primary regions affected in Alzheimer's disease, compared to apoE3 TR mice. In the current study, we determined how age and varying APOE genotype affect synaptic integrity of amygdala neurons by comparing electrophysiological and morphometric properties in C57BL6, apoE knockout, and human apoE3, E4 and E2/4 TR mice at 1 month and 7 months. The apoE4 TR mice exhibited the lowest level of excitatory synaptic activity and dendritic arbor compared to other cohorts at both ages, and became progressively worse by 7 months. In contrast, the apoE3 TR mice exhibited the highest synaptic activity and dendritic arbor of all cohorts at both ages. C57BL6 mice displayed virtually identical synaptic activity to apoE3 TR mice at 1 month; however this activity decreased by 7 months. ApoE knockout mice exhibited a similar synaptic activity profile with apoE4 TR mice at 7 months. Consistent with previous reports that APOE2 confers protection, the apoE4-dependent deficits in excitatory activity were significantly attenuated in apoE2/4 TR mice at both ages. These findings demonstrate that expression of human apoE4 contributes to functional deficits in the amygdala very early in development and may be responsible for altering neuronal circuitry that eventually leads to cognitive and affective disorders later in life.


Asunto(s)
Amígdala del Cerebelo/citología , Apolipoproteína E2/metabolismo , Apolipoproteína E4/metabolismo , Neuronas/fisiología , Sinapsis/genética , Factores de Edad , Animales , Apolipoproteína E2/genética , Apolipoproteína E4/genética , Apolipoproteínas E/deficiencia , Potenciales Postsinápticos Excitadores/genética , Genotipo , Humanos , Técnicas In Vitro , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Técnicas de Placa-Clamp , Método Simple Ciego
9.
Neuroscience ; 164(4): 1389-97, 2009 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-19786076

RESUMEN

Previous behavioral studies have shown that neuropeptides intrinsic to the amygdala formation can alter fear and anxiety states. We have previously shown that the anxiogenic neuropeptide cholecystokinin (CCK) increases inhibitory neurotransmission in basolateral amygdala. We have since observed that CCK induces synchronized rhythmic activity composed of compound postsynaptic potentials (cPSPs). We have now further characterized these cPSPs by inducing cPSPs routinely in 5 mM extracellular K(+). CCK facilitated cPSP occurrence in a dose dependent manner in brain slices from both young and mature rats. The cPSPs were attenuated by glutamate receptor antagonists (NBQX or DL-AP5) or low concentrations of GABA(A) receptor antagonists (bicuculline methiodide (BMI), SR95531, or picrotoxin), but not by the GABA(B) receptor antagonist, CGP52432. Low concentrations of tetrodotoxin (TTX, 10 nM) also attenuated the cPSPs. The Na-K-2Cl cotransporter blocker, bumetanide (1 or 10 microM) also blocked the cPSPs. The anxiogenic neuropeptide corticotropin-releasing factor (CRF) facilitated cPSPs while anxiolytic neuropeptides (neuropeptide Y (NPY) and somatostatin) attenuated cPSPs. The benzodiazepine agonist diazepam dose-dependently modulated cPSPs. Mefloquine facilitated cPSPs within 10 min of application. We hypothesize that cPSPs are generated by positive feedback between a subset of interneurons and a subset of glutamatergic projection neurons.


Asunto(s)
Amígdala del Cerebelo/efectos de los fármacos , Neuropéptidos/farmacología , Potenciales Sinápticos/efectos de los fármacos , Potenciales de Acción , Amígdala del Cerebelo/fisiología , Animales , Ansiolíticos/farmacología , Cationes Monovalentes , Cloruros/fisiología , Colecistoquinina/farmacología , Hormona Liberadora de Corticotropina/farmacología , Diazepam/farmacología , Uniones Comunicantes/efectos de los fármacos , Uniones Comunicantes/fisiología , Homeostasis , Masculino , Mefloquina/farmacología , Neuropéptido Y/farmacología , Técnicas de Placa-Clamp , Periodicidad , Potasio/líquido cefalorraquídeo , Ratas , Receptores de GABA/fisiología , Receptores de Glutamato/fisiología , Somatostatina/farmacología
10.
Neuropeptides ; 41(6): 453-63, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17904218

RESUMEN

The neuropeptide cholecystokinin (CCK) is anxiogenic in studies of human and animal behavior. As the amygdala formation has been implicated in generation of emotional states such as anxiety, we tested the effect of CCK on spontaneous synaptic events in the basolateral amygdala (BLA) using whole cell patch recordings in rat brain slice preparation. We found that CCK increased the frequency of spontaneous inhibitory postsynaptic potentials (sIPSPs) and currents (sIPSCs). This effect was blocked by the fast sodium channel blocker tetrodotoxin (TTX), indicating that the CCK effect is likely mediated by direct excitation of GABAergic interneurons. The CCK(B) receptor subtype antagonist, CR2945, blocked the CCK effect, while CCK4, a specific CCK(B) agonist, increased sIPSC frequency. We hypothesize that these actions may underlie the anxiogenic effects of CCK observed in behavioral studies.


Asunto(s)
Amígdala del Cerebelo/fisiología , Encéfalo/fisiología , Colecistoquinina/fisiología , Transmisión Sináptica , Animales , Ansiedad , Colecistoquinina/antagonistas & inhibidores , Potenciales Postsinápticos Inhibidores , Interneuronas , Técnicas de Placa-Clamp , Ratas , Ácido gamma-Aminobutírico
11.
Minerva Pediatr ; 56(1): 1-28, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15249911

RESUMEN

Pediatric interventional catheterization is an expanding specialty with a range of mature, emerging, and investigative procedures and technologies. Many dysfunctional obstructions and/or shunts caused by congenital heart defects may be treated or significantly palliated in the catheterization laboratory. These include valvar pulmonary or aortic stenosis, the patent ductus arteriosus, coarctation of the aorta, branch pulmonary stenosis, atrial septal defects and even ventricular septal defects. Valve replacement technology, approaches to complex heart diseases such as single ventricle, and fetal interventions are subjects of active investigations. A comprehensive review of the present and future of interventional pediatric cardiology is presented.


Asunto(s)
Cardiología/tendencias , Pediatría/tendencias , Cateterismo Cardíaco , Procedimientos Quirúrgicos Cardíacos/métodos , Servicio de Cardiología en Hospital/tendencias , Cateterismo de Swan-Ganz , Niño , Servicios de Salud del Niño/tendencias , Cardiopatías/congénito , Cardiopatías/diagnóstico por imagen , Defectos del Tabique Interventricular/cirugía , Humanos , Radiografía
12.
Neuropharmacology ; 46(1): 1-9, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14654092

RESUMEN

Benzodiazepines are among the most widely prescribed therapeutic agents, having anxiolytic, anticonvulsant, sedative/hypnotic, and amnestic properties (Mehta and Ticku, Brain Res. Rev. 29 (1999) 196). Recent research indicates that these disparate actions are dissociable (Nature 401 (1999) 796; Science 290 (2000) 131; Kralic et al., Neuropharmacology 43 (2002) 685). Behavioral studies indicate that the amygdala plays a critical role in the anxiolytic effect of benzodiazepines (Nagy et al., Neuropharmacology 18 (1979) 573; The amygdala: anxiety and benzodiazepines. The Amygdala: a Functional Analysis. p. 195). However, the neuronal substrates of this anxiolytic effect remain unclear. Our study characterizes the physiological response to acute application of the benzodiazepine diazepam and the non-benzodiazepine sedative zolpidem using whole cell patch recording in two discrete amygdala subnuclei. We found that acute application of diazepam enhances GABA(A) receptor-mediated inhibitory postsynaptic currents (IPSCs) with equal potency in the basolateral (BL) and central (Ce) amygdala subnuclei. However, zolpidem enhanced IPSCs with similar potency only in the BL, and was effective in the Ce only at high concentrations. This finding is in agreement with histochemical data regarding the localization of GABA(A) receptor isoforms in the amygdala (J. Comp. Neurol. 359 (1995) 154; Brain Res. 964 (2003) 91) and suggests that anxiolytic effects of allosteric modulators of the GABA(A) receptor may be further dissociated from their hypnotic/sedative effects.


Asunto(s)
Amígdala del Cerebelo/efectos de los fármacos , Bicuculina/análogos & derivados , Diazepam/farmacología , Agonistas del GABA/farmacología , Moduladores del GABA/farmacología , Piridinas/farmacología , Valina/análogos & derivados , Animales , Animales Recién Nacidos , Bicuculina/farmacología , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Estimulación Eléctrica , Potenciales Evocados/efectos de los fármacos , Potenciales Evocados/efectos de la radiación , Antagonistas de Aminoácidos Excitadores/farmacología , Antagonistas del GABA/farmacología , Técnicas In Vitro , Masculino , Inhibición Neural/efectos de los fármacos , Técnicas de Placa-Clamp/métodos , Quinoxalinas/farmacología , Ratas , Ratas Sprague-Dawley , Valina/farmacología , Zolpidem
13.
J Dairy Sci ; 85(3): 504-6, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11949852

RESUMEN

Eight lactating Holstein dairy cows (80 d in milk) were used to examine the effects of exogenous bovine somatotropin (bST) on hepatic contents of mRNA encoding pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK), and microsomal triglyceride transfer protein (MTP). Concentrations of bST in plasma were higher and milk production increased 20% in bST-treated cows. Liver samples from cows treated with bST had significantly higher total lipid contents than those from control cows. Although there were small numerical tendencies, neither triglyceride concentrations in liver nor nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), or glucose in plasma differed significantly between bST-treated and control cows. Short-term bST treatment had no detectable effects on contents of PC, PEPCK, and MTP mRNA in the liver. In summary, exogenous bST stimulation of milk production is not mediated through enhanced liver gluconeogenesis, but may involve partitioning of glucose and fatty acids for preferential use by the mammary gland.


Asunto(s)
Bovinos/metabolismo , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Glucosa/metabolismo , Hormona del Crecimiento/farmacología , Lactancia/efectos de los fármacos , Hígado/enzimología , Leche/metabolismo , Animales , Proteínas Portadoras/metabolismo , Bovinos/fisiología , Metabolismo Energético , Ácidos Grasos no Esterificados/sangre , Femenino , Fosfoenolpiruvato Carboxiquinasa (ATP)/metabolismo , Piruvato Carboxilasa/metabolismo , ARN Mensajero/análisis
14.
Biochemistry ; 40(45): 13583-91, 2001 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-11695906

RESUMEN

Salmonella phage P22, which serves as an assembly paradigm for icosahedral double-stranded DNA viruses, packages its viral genome through a capsid channel (portal) comprising 12 copies of a 725-residue subunit. Secondary and tertiary structures of the portal subunit in monomeric and dodecameric states have been investigated by Raman spectroscopy using a His6-tagged recombinant protein that self-assembles in vitro [Moore, S. D., and Prevelige, P. E., Jr. (2001) J. Biol. Chem. 276, 6779-6788]. The portal protein exhibits Raman secondary structure markers typical of a highly alpha-helical subunit fold that is little perturbed by assembly. On the other hand, Raman markers of subunit side chains change dramatically with assembly, an indication of extensive changes in side chain environments. The cysteinyl Raman signature of the portal consists of a complex pattern of sulfhydryl stretching bands, revealing diverse hydrogen-bonding states for the four S-H groups per subunit (Cys 153, Cys 173, Cys 283, and Cys 516). Upon assembly, the population of strongly hydrogen-bonded S-H groups decreases, while the population of weakly hydrogen-bonded S-H groups increases, implying that specific intrasubunit S-H.X hydrogen bonds must be weakened to effect dodecamer assembly and that the molecular mechanism involves reorganization of subunit domains without appreciable changes in domain conformations. Comparison with other viral protein assemblies suggests an assembly process not requiring metastable intermediates. The recently published X-ray structure of the phi29 portal [Simpson, A. A., et al. (2000) Nature 408, 745-750] shows that residues 125-225 lining the channel surface form alpha-helical modules spaced by short beta-strands and turns; a surprisingly close secondary structure homology is predicted for residues 240-350 of the P22 portal, despite no apparent sequence homology. This motif is proposed as an evolutionarily conserved domain involved in DNA translocation.


Asunto(s)
Bacteriófago P22/química , Proteínas de la Cápside , Cápside/química , Bacteriófago P22/fisiología , Cisteína/química , Modelos Moleculares , Conformación Proteica , Espectrometría Raman/métodos , Triptófano/química , Tirosina/química , Ensamble de Virus/fisiología
15.
J Neurophysiol ; 86(3): 1422-9, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11535688

RESUMEN

Although the synaptic physiology of the amygdala has been studied with single neuron recordings, the properties of the networks between the various nuclei have resisted characterization because of the limitations of field recording in a neuronally diffuse structure. We addressed this issue in the rat amygdala complex in vitro by using a photodiode array coupled with a voltage-sensitive dye. Low-intensity single pulse stimulation of the lateral amygdala nucleus produced a complex multi-phasic potential. This signal propagated to the basolateral nucleus and the amygdalostriatal transition zone but not to the central nucleus. The local potential, which depended on both synaptic responses and activation of voltage-dependent ion channels, was reduced in amplitude by the non-N-methyl-D-aspartate (non-NMDA) glutamate receptor antagonist 6,7-dinitroquinoxaline (DNQX) and reduced to a lesser extent by the NMDA glutamate receptor antagonist D-2-amino-5-phosphonovaleric acid (D-APV). We next characterized the less complex signals that propagated to more distal regions with or without the addition of the GABA receptor antagonist bicuculline (BIC). BIC alone greatly increased the signal propagation and permitted activation of previously silent areas within the amygdala. DNQX blocked signal propagation to amygdala regions outside of La, even in the presence of BIC, whereas D-APV had minimal effects on these distal signals. These data represent several novel findings: the characterization of the multi-component potential near the site of stimulation, the gating of signal propagation within the amygdala by GABAergic inhibition, the critical role of non-NMDA receptor-mediated depolarization in signal propagation, and the lack of a role for NMDA receptors in maintaining propagation.


Asunto(s)
Amígdala del Cerebelo/fisiología , Receptores AMPA/fisiología , Receptores de GABA/fisiología , Receptores de N-Metil-D-Aspartato/fisiología , Transmisión Sináptica/fisiología , 2-Amino-5-fosfonovalerato/farmacología , Animales , Bicuculina/farmacología , Colorantes , Antagonistas de Aminoácidos Excitadores/farmacología , Antagonistas del GABA/farmacología , Procesamiento de Imagen Asistido por Computador , Masculino , Técnicas de Cultivo de Órganos , Quinoxalinas/farmacología , Ratas , Ratas Sprague-Dawley , Transmisión Sináptica/efectos de los fármacos
16.
J Clin Psychopharmacol ; 21(1): 94-8, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11199956

RESUMEN

This study was conducted to evaluate the effect of bupropion sustained-release (SR) on smoking cessation in patients with chronic posttraumatic stress disorder (PTSD). Fifteen veterans with chronic PTSD who desired to stop smoking enrolled in a 12-week double-blind evaluation of bupropion SR and placebo. Patients were randomly assigned in a 2:1 ratio to receive either bupropion SR or placebo. Bupropion SR was initiated at 150 mg daily for 3 or 4 days and increased to a final dose of 150 mg twice daily (300 mg daily total). Ten patients received bupropion SR and five received placebo. Nine of the patients who received bupropion SR were already being treated with at least one other psychotropic medication. One of the ten patients did not complete the study because of medication side effects. Eighty percent of patients receiving bupropion SR successfully stopped smoking by the end of week 2, and 6 (60%) of these 10 maintained smoking cessation at the study endpoint (week 12). At the 6-month follow-up, 40% of the patients (4 of 10) who received bupropion SR maintained smoking cessation. One (20%) of the five patients who received placebo stopped smoking and maintained smoking cessation at the 6-month follow-up. Bupropion SR was generally well-tolerated in combination with other psychotropic medications. Bupropion SR may be effective in helping patients who desire to quit smoking and who also have a concomitant anxiety disorder, such as PTSD.


Asunto(s)
Antidepresivos de Segunda Generación/uso terapéutico , Bupropión/uso terapéutico , Cese del Hábito de Fumar , Trastornos por Estrés Postraumático/complicaciones , Adulto , Antidepresivos de Segunda Generación/efectos adversos , Bupropión/efectos adversos , Enfermedad Crónica , Preparaciones de Acción Retardada , Método Doble Ciego , Estudios de Seguimiento , Humanos , Masculino , Trastornos por Estrés Postraumático/tratamiento farmacológico , Resultado del Tratamiento
17.
J Biol Chem ; 276(9): 6779-88, 2001 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-11092883

RESUMEN

The Salmonella typhimurium bacteriophage P22 assembles an icosahedral capsid precursor called a procapsid. The oligomeric portal protein ring, located at one vertex, comprises the conduit for DNA entry and exit. In conjunction with the DNA packaging enzymes, the portal ring is an integral component of a nanoscale machine that pumps DNA into the phage head. Although the portal vertex is assembled with high fidelity, the mechanism by which a single portal complex is incorporated during procapsid assembly remains unknown. The assembly of bacteriophage P22 portal rings has been characterized in vitro using a recombinant, His-tagged protein. Although the portal protein remained primarily unassembled within the cell, once purified, the highly soluble monomer assembled into rings at room temperature at high concentrations with a half time of approximately 1 h. Circular dichroic analysis of the monomers and rings indicated that the protein gained alpha-helicity upon polymerization. Thermal denaturation studies suggested that the rings contained an ordered domain that was not present in the unassembled monomer. A combination of 4,4'-dianilino-1,1'-binapthyl-5,5'-disulfonic acid (bis-ANS) binding fluorescence studies and limited proteolysis revealed that the N-terminal portion of the unassembled subunit is meta-stable and is susceptible to structural perturbation by bis-ANS. In conjunction with previously obtained data on the behavior of the P22 portal protein, we propose an assembly model for P22 portal rings that involves a meta-stable monomeric subunit.


Asunto(s)
Bacteriófago P22/fisiología , Proteínas Virales/química , Ensamble de Virus , Naftalenosulfonatos de Anilina/metabolismo , Dicroismo Circular , Polímeros/química , Pliegue de Proteína , Estructura Secundaria de Proteína , Proteínas Virales/fisiología
18.
J Consult Clin Psychol ; 68(5): 923-7, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11068979

RESUMEN

The present study assessed drug use and the validity of self-reports of substance use among help-seeking veterans referred to a specialty clinic for the assessment of posttraumatic stress disorder (PTSD). Patients (n = 341) were asked to provide a urine sample for use in drug screening as part of an evaluation of PTSD. Self-reports of substance use were compared with same-day supervised urine samples for 317 patients who volunteered to participate in a drug screening. Results suggested that self-reports were generally quite valid. Only 8% of the cases involved patients not reporting substance use detected by urine screens. A total of 42% of the participants were identified as using drugs of abuse (excluding alcohol) through self-report and urine drug screens. Among participants using drugs, PTSD diagnosis was significantly associated with greater marijuana and depressant use as compared with stimulant (cocaine and amphetamines) use.


Asunto(s)
Autorrevelación , Detección de Abuso de Sustancias/métodos , Trastornos Relacionados con Sustancias/diagnóstico , Trastornos Relacionados con Sustancias/orina , Veteranos/psicología , Adulto , Cannabinoides/orina , Depresores del Sistema Nervioso Central/orina , Estimulantes del Sistema Nervioso Central/orina , Ensayo de Inmunoadsorción Enzimática , Alucinógenos/orina , Hospitales de Veteranos , Humanos , Drogas Ilícitas/orina , Masculino , Persona de Mediana Edad , North Carolina , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Trastornos Relacionados con Sustancias/psicología , Encuestas y Cuestionarios
19.
J Consult Clin Psychol ; 68(2): 269-76, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10780127

RESUMEN

The present study investigated the relationship between daily diary affect ratings and ambulatory cardiovascular activity in 117 male Vietnam combat veterans (61 with posttraumatic stress disorder [PTSD] and 56 without PTSD). Participants completed 12-14 hr of ambulatory monitoring and daily diary affect ratings. Compared with veterans without PTSD, veterans with PTSD reported higher negative affect and lower positive affect in daily diary ratings. No differences were detected for mean laboratory initial recordings or mean ambulatory heart rate (HR), systolic blood pressure (SBP), or diastolic blood pressure (DBP). However, compared with veterans without PTSD, veterans with PTSD demonstrated higher SBP and DBP variability and a higher proportion of HR activity (compared with initial recording values) during daily activity. There was a significant Time of Day x Group interaction for mean HR, with a trend for PTSD participants to maintain HR levels during evening hours.


Asunto(s)
Nivel de Alerta , Trastornos de Combate/diagnóstico , Electrocardiografía Ambulatoria , Veteranos/psicología , Afecto/fisiología , Nivel de Alerta/fisiología , Sistema Nervioso Autónomo/fisiopatología , Presión Sanguínea/fisiología , Trastornos de Combate/fisiopatología , Trastornos de Combate/psicología , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad
20.
Cytogenet Cell Genet ; 88(1-2): 35-7, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10773661

RESUMEN

Copper does not exist in a free state within cells but is found consistently bound to metalloproteins. Specific metallochaperones escort copper to numerous targets within the cell, providing protection from the toxic effects of intracellular free copper. Many metallochaperones have been characterized in yeast, mouse, and human. To further characterize mouse metallochaperones, we cloned murine Ccsd from an adult mouse cDNA brain library, including both the coding region and the 5' and 3' UTRs. We obtained a 1,174-bp cDNA with an 825-bp open reading frame, translating a 274 amino acid protein that is 86.9% identical to human CCS. Using a mouse x hamster radiation hybrid panel, we mapped Ccsd to a proximal position on mouse chromosome 19. We mapped human CCS to 11q13 (homologous with mouse chromosome 19), utilizing a human x hamster radiation hybrid panel. The human and mouse metallochaperones are ubiquitously expressed in the major tissues of the body but seem to have different transcription products.


Asunto(s)
Mapeo Cromosómico , Cromosomas Humanos Par 11/genética , Chaperonas Moleculares/genética , Secuencia de Aminoácidos , Animales , Encéfalo/metabolismo , Clonación Molecular , Cricetinae , Perfilación de la Expresión Génica , Humanos , Células Híbridas , Escala de Lod , Ratones , Chaperonas Moleculares/química , Datos de Secuencia Molecular , Peso Molecular , Sistemas de Lectura Abierta/genética , ARN Mensajero/análisis , ARN Mensajero/genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Regiones no Traducidas/genética
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