RESUMEN
The endothelial glycocalyx (EG), the luminal cover of endothelial cells, is considered to be atheroprotective. During atherogenesis, platelets adhere to the vessel wall, possibly triggered by simultaneous EG modulation. It was the objective of this study to investigate both EG thickness and platelet-vessel wall interactions during atherogenesis in the same experimental model. Intravital fluorescence microscopy was used to study platelet-vessel wall interactions in vivo in common carotid arteries and bifurcations of C57bl6/J (B6) and apolipoprotein E knock-out (ApoE-/-) mice (age 7 - 31 weeks). At the same locations, EG thickness was determined ex vivo using two-photon laser scanning microscopy. In ApoE-/- bifurcations the overall median level of adhesion was 48 platelets/mm2 (interquartile range: 16 - 80), which was significantly higher than in B6 bifurcations (0 (0 - 16), p = 0.001). This difference appeared to result from a significant age-dependent increase in ApoE-/- mice, while no such change was observed in B6 mice. At the same time, the EG in ApoE-/- bifurcations was significantly thinner than in B6 bifurcations (2.2 vs. 2.5 µm, respectively; p < 0.05). This resulted from the fact that in B6 bifurcations EG thickness increased with age (from 2.4 µm in young mice to 3.0 µm in aged ones), while in bifurcations of ApoE-/- mice this growth appeared to be absent (2.2 µm at all ages). During atherogenesis, platelet adhesion to the wall of the carotid artery bifurcation increases significantly. At the same location, EG growth with age is hampered. Therefore, glycocalyx-reinforcing strategies could possibly ameliorate atherosclerosis.
Asunto(s)
Aterosclerosis/patología , Plaquetas/patología , Arterias Carótidas/patología , Células Endoteliales/patología , Glicocálix/patología , Adhesividad Plaquetaria , Factores de Edad , Animales , Apolipoproteínas E/genética , Aterosclerosis/sangre , Aterosclerosis/genética , Modelos Animales de Enfermedad , Hiperlipidemias/complicaciones , Hiperlipidemias/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microscopía Confocal , Microscopía Fluorescente , Microscopía de Fluorescencia por Excitación Multifotónica , Microscopía por Video , Factores de TiempoRESUMEN
Only a few decades after 1492, when Christopher Columbus arrived on a Caribbean island and Pedro Alvares Cabral claimed Brazil for Portugal in 1500, a German mercenary gave the first description of stingless bees in 1557. He got to know them when he was imprisoned for months by an anthropophagous tribe in the coastal region of Santos, today in the State of São Paulo. This rather short but nevertheless extremely exact record on stingless bees is hidden in the first book on Brazil. Three species and important aspects of their life history were treated. This early description has been completely overlooked by bee scientists until now. My note intends to close this evident gap.
Asunto(s)
Abejas , Publicaciones , Animales , BrasilRESUMEN
Nest architecture and demography of the non leaf-cutting fungus-growing ant species Mycocepurus goeldii and M. smithii (Attini: Formicidae) were studied in an agroforest habitat near Manaus, Brazil during the excavation of 13 nests. Both species built their nests in two different ways. The first type possessed a "tree-like" architecture, in which a vertical tunnel led downwards and lateral tunnels branched off at 90 degrees angles from the main tunnel, with a chamber at the end of each side branch. Alternatively, other nests displayed a "necklace-like" architecture, where the main tunnel also led down vertically, but entered each chamber from the top and exited it at the bottom, resulting in an architecture where chambers appeared like pearls on a necklace. The nest systems of M. goeldii and M. smithii consisted of 1-21 or 1-15 chambers, respectively. Of 199 excavated chambers, 57 % contained fungus-gardens. Chambers not containing fungus gardens were filled with organic matter from decaying fungus gardens or earthworm feces. Only M. smithii workers deposited loose soil in abandoned chambers during the construction of new nest chambers. Workers of M. smithii constructed significantly smaller chambers than those of M. goeldii. In both species, fungus garden-containing chambers were larger than non-garden chambers and were homogenously distributed in the soil between 17 cm and 105 cm depth. Neither fungus gardens nor abandoned chambers were encountered more frequently in deeper or shallower soil strata indicating that ants of both species did not abandon shallower versus deeper chambers, or move the colony to deeper soil layers with increasing colony age. Fungus gardens were suspended from the ceiling of the subterranean chambers and originated as small mycelial tufts. Through continual addition of organic debris, the tufts first grew vertically to strands before they expanded laterally until most of the chamber volume was filled with fungus garden curtains. New garden chambers were found at depths ranging from 17 to 83 cm, suggesting that new garden chambers were not constructed in deeper soil strata with increasing colony age. The size of M. goeldii and M. smithii colonies was dependent on their age. Worker counts varied between a few individuals in recently founded colonies and 1352 workers in an adult M. goeldii colony. The ratio of worker number per fungus garden chamber was higher in M. goeldii colonies than M. smithii colonies; the M. goeldii colonies were more populous. Both species were oligogynous with a maximum of four and three queens observed in a single chamber of M. goeldii and M. smithii, respectively. The reproductive status of each queen was unknown. In both species the ratio of brood to workers was approximately 2:3. Larvae and pupae were unequally distributed throughout the nest, but were only located in chambers containing a garden. Their location in the chamber was dependent upon the developmental state of the fungus garden.
Asunto(s)
Hormigas/fisiología , Hongos/fisiología , Comportamiento de Nidificación/fisiología , Animales , Hongos/crecimiento & desarrollo , Especificidad de la EspecieRESUMEN
Trypanosoma cruzi, the agent of Chagas disease, is known to cause enhanced nitric oxide (NO) production, which might be involved in host resistance. The inducible nitric-oxide-synthase (iNOS) is assumed to be responsible for the NO increase after several infections. We studied the potential role of NO in Calomys callosus, a natural reservoir of this protozoan parasite. The concentration of NO was determined in spleen and liver of animals infected with two different T. cruzi strains, BOL and BOL-SB. Furthermore, the iNOS mRNA expression was quantified in the same cell types. NO production was detectable in both tissues exhibiting only slight differences compared to non-infected controls. All measured NO values were significantly lower than those reported for a number of different mouse strains, which displayed extremely enhanced NO levels after T. cruzi infection. Surprisingly, iNOS mRNA expression was induced in infected C. callosus but without subsequent increase of NO levels, indicating a post-transcriptional regulation mechanism. In summary, our results, indicate that the tolerance of C. callosus to T. cruzi is only accompanied by non-toxic NO intracellular concentrations.
Asunto(s)
Óxido Nítrico/metabolismo , Sigmodontinae/metabolismo , Sigmodontinae/parasitología , Trypanosoma cruzi/fisiología , Animales , Células Cultivadas , Reservorios de Enfermedades , Regulación Enzimológica de la Expresión Génica , Hepatocitos/enzimología , Hepatocitos/parasitología , Interacciones Huésped-Parásitos , Ratones , Óxido Nítrico Sintasa de Tipo II/genética , Óxido Nítrico Sintasa de Tipo II/metabolismo , Parasitemia , ARN Mensajero/metabolismo , Bazo/citología , Bazo/parasitologíaRESUMEN
The ectoparasitic bee mite, Varroa destructor, is highly adapted to its natural and adopted honey bee hosts, Apis cerana and Apis mellifera. Adult females perforate the integument of bee pupae in such a way that they and their progeny can feed. We examined the wounds that founder females made, and usually found one, and rarely up to three, integumental wounds on pupae of A. mellifera multiply infested by V. destructor. The punctures were mainly on the 2nd abdominal sternite of the host. These perforations are used repeatedly as feeding sites by these hemolymph-sucking mites and by their progeny. The diameter of the wounds increased during pupal development. In brood cells containing 4-5 invading female mites and their progeny, healing of the wound is delayed, normally occurring just before the imaginal moult of the bee pupa. These wounds are subject to microbial infections, and they are relevant to the evolution of behavioral traits in these parasitic mites and their relations to host bees.
Asunto(s)
Animales , Masculino , Femenino , Abejas/parasitología , Mordeduras y Picaduras/parasitología , Ácaros/fisiología , Azul de Tripano , Conducta Alimentaria , Microscopía Electrónica de Rastreo , Mordeduras y Picaduras/patología , Pupa/parasitología , Pupa/ultraestructura , Interacciones Huésped-ParásitosRESUMEN
Diploid males have long been considered a curiosity contradictory to the haplo-diploid mode of sex determination in the Hymenoptera. In Apis mellifera, 'false' diploid male larvae are eliminated by worker cannibalism immediately after hatching. A 'cannibalism substance' produced by diploid drone larvae to induce worker-assisted suicide has been hypothesized, but it has never been detected. Diploid drones are only removed some hours after hatching. Older larvae are evidently not regarded as 'false males' and instead are regularly nursed by the brood-attending worker bees. As the pheromonal cues presumably are located on the surface of newly hatched bee larvae, we extracted the cuticular secretions and analyzed their chemical composition by gas chromatograph-mass spectrometry (GC-MS) analyses. Larvae were sexed and then reared in vitro for up to three days. The GC-MS pattern that was obtained, with alkanes as the major compounds, was compared between diploid and haploid drone larvae. We also examined some physical parameters of adult drones. There was no difference between diploid and haploid males in their weight at the day of emergence. The diploid adult drones had fewer wing hooks and smaller testes. The sperm DNA content was 0.30 and 0.15 pg per nucleus, giving an exact 2:1 ratio for the gametocytes of diploid and haploid drones, respectively. Vitellogenin was found in the hemolymph of both types of imaginal drones at 5 to 6 days, with a significantly lower titer in the diploids.
Asunto(s)
Animales , Masculino , Femenino , ADN , Abejas/genética , Diferenciación Sexual/genética , Diploidia , Espermatozoides/química , Haploidia , Cromatografía de Gases y Espectrometría de Masas , Hemolinfa/química , Larva , Vitelogeninas/sangreRESUMEN
The intracellular parasite Trypanosoma cruzi, the causative agent of Chagas disease, is known to comprise heterogeneous populations. One possibility to explain the obviously distinct phenotypes of different T. cruzi strains is differential expression of particular genes. This could result in environmental adaptations of the parasite within host organs, leading to distinct clinical symptoms. With the aim of identifying differentially expressed genes, we examined different T. cruzi strains by suppression subtractive hybridization analysis. The isolated clones were sequenced and Blasted for sequence-homology with known T. cruzi genes. A stage-specific glycoprotein (82gp), an 85-kDa protein with homology to heat-shock proteins, a beta-tubulin gene, a hexosetransporter, a dehydrogenase/ prostaglandin F2alpha-synthase and a cathepsin B-like protease were identified. The expression of these genes was analyzed by RT-PCR. Diverse expression patterns were detected for different T. cruzi strains, but no specific correlation between the gene expression and the classification of groups could be found. We discuss the presumed importance of these T. cruzi gene expression patterns for future strategies of molecular therapy of Chagas disease. For pathological studies, other parameters such as distinct gene/antigen expression could also be of interest, because they probably likewise correlate with distinct phenotypes.
Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Trypanosoma cruzi/clasificación , Animales , Enfermedad de Chagas/parasitología , ADN Protozoario/análisis , Humanos , Estadios del Ciclo de Vida , Hibridación de Ácido Nucleico/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Trypanosoma cruzi/genética , Trypanosoma cruzi/crecimiento & desarrolloRESUMEN
AIM: Development of a fast, automated and reliable screening method for screening of large collections of bacterial strains with minimal handling time. METHODS AND RESULTS: The method is based on the injection of a small headspace sample (100 microl) from culture vials (2 ml) in 96-well format directly into the mass spectrometry (MS). A special sample tray has been developed for liquid media, and anaerobically grown cultures. In principle, all volatile components can be measured, but a representative mass fragment has to be obtained in the MS. Representative masses for 3-methylbutanal, 2-methylpropanal and benzaldehyde are 58, 72 and 105, respectively. In 1 day over 1500 samples could be analysed and the coefficient of variation for the response was <5%. CONCLUSION: Screening of 72 strains belonging to the genus Lactococcus in quadruple on the production of the key-flavour compound 3-methylbutanal illustrated the effectiveness of the method. Furthermore, knowledge of the biochemistry and physiology of 3-methylbutanal formation was used to optimize the composition of the growth medium to enhance 3-methylbutanal production, and thereby improve the screening. SIGNIFICANCE AND IMPACT OF THE STUDY: A commonly used method to control flavour formation in fermented food products is the selection of bacterial strains, which are able to produce the desired flavour compounds. As large collections of strains are available for such screenings, studying biodiversity of micro-organisms on the level of metabolic routes is strongly facilitated by highly automated high throughput screening methods for measuring enzyme activities or production of metabolites. Therefore, this method will be a useful tool for selecting flavour-producing strains and for enhancing starter culture development.
Asunto(s)
Aldehídos/análisis , Aromatizantes/análisis , Microbiología de Alimentos , Lactococcus lactis/metabolismo , Benzaldehídos/análisis , Medios de Cultivo , Fermentación , Cromatografía de Gases y Espectrometría de Masas/métodos , Espectrometría de Masas/métodos , Reproducibilidad de los ResultadosRESUMEN
From wounds of honey bee pupae, caused by the mite Varroa destructor, coccoid bacteria were isolated and identified as Melissococcus pluton. The bacterial isolate was grown anaerobically in sorbitol medium to produce a toxic compound that was purified on XAD columns, gelfiltration and preparative HPLC. The toxic agent was identified by GC-MS and FTICR-MS as tyramine. The toxicity of the isolated tyramine was tested by a novel mobility test using the protozoon Stylonychia lemnae. A concentration of 0.2 mg/ml led to immediate inhibition of mobility. In addition the toxicity was studied on honey bee larvae by feeding tyramine/water mixtures added to the larval jelly. The lethal dosis of tyramine on 4-5 days old bee larvae was determined as 0.3 mg/larvae when added as a volume of 20 microl to the larval food in brood cells. Several other biogenic amines, such as phenylethylamine, histamine, spermine, cadaverine, putrescine and trimethylamine, were tested as their hydrochloric salts for comparison and were found to be inhibitory in the Stylonychia mobility test at similar concentrations. A quantitative hemolysis test with human red blood cells revealed that tyramine and histamine showed the highest membranolytic activity, followed by the phenylethylamine, trimethylamine and spermine, while the linear diamines, cadaverine and putrescine, showed a significantly lower hemolysis when calculated on a molar amine basis. The results indicate that tyramine which is a characteristic amine produced by M. pluton in culture, is the causative agent of the observed toxic symptoms in bee larvae. Thus this disease, known as European foulbrood, is possibly an infection transmitted by the Varroa destructor mite.
Asunto(s)
Abejas/microbiología , Bacterias Grampositivas/metabolismo , Bacterias Grampositivas/patogenicidad , Tiramina/toxicidad , Animales , Abejas/parasitología , Aminas Biogénicas/toxicidad , Movimiento Celular/efectos de los fármacos , Cromatografía , Cromatografía Líquida de Alta Presión , Cilióforos/efectos de los fármacos , Eritrocitos/efectos de los fármacos , Cromatografía de Gases y Espectrometría de Masas , Bacterias Grampositivas/crecimiento & desarrollo , Bacterias Grampositivas/aislamiento & purificación , Hemólisis , Humanos , Larva/efectos de los fármacos , Ácaros/microbiología , Ácaros/fisiología , Pupa/microbiología , Pupa/parasitología , Tiramina/biosíntesis , Tiramina/química , Tiramina/aislamiento & purificaciónRESUMEN
Various microorganisms, belonging to the genera Lactococcus, Lactobacillus, Streptococcus, Leuconostoc, Bifidobacterium, Propionibacterium, Brevibacterium, Corynebacterium and Arthrobacter, used in dairy fermentations such as cheese making, were analysed for their potential to convert leucine into flavour components, most notably 3-methylbutanal. A large variation between and within species was observed for various enzyme activities involved in the conversion pathway, e.g. transaminases, alpha-hydroxy acid dehydrogenase and alpha-keto acid decarboxylase. In particular, alpha-keto acid decarboxylase activity-leading to 3-methylbutanal-was found to be present in only two of the strains tested. It is proposed that this activity is rate-controlling in the conversion pathway leading to the flavour compound 3-methylbutanal.
Asunto(s)
Aldehídos/metabolismo , Bacterias/metabolismo , Queso/microbiología , Aromatizantes , Leucina/metabolismo , 3-Metil-2-Oxobutanoato Deshidrogenasa (Lipoamida)/metabolismo , Oxidorreductasas de Alcohol/metabolismo , Arthrobacter/metabolismo , Bifidobacterium/metabolismo , Biotransformación , Brevibacterium/metabolismo , Corynebacterium/metabolismo , Fermentación , Microbiología de Alimentos , Lactobacillus/metabolismo , Lactococcus/metabolismo , Leuconostoc/metabolismo , Propionibacterium/metabolismo , Streptococcus/metabolismo , Transaminasas/metabolismoRESUMEN
The damage to western honey bee, Apis mellifera, colonies caused by the originally Asian ectoparasitic mite Varroa destructor is mainly a consequence of the infestation of host bee pupae. In the capped brood cell, female mites puncture the host's integument at preferred sites in order to suck haemolymph. Due to repeated feeding by the mother mite and her progeny, these perforations are kept open until shortly before the imaginal moult of the bee. Thereafter scarring takes place, thus preventing microbial infection after the adult bee has emerged from the protected environment of the sealed brood cell. However, colonies of various bacteria were found in the open wounds of about 15-30% of all inspected host pupae with an abundance depended on the level of host brood cell infestation by the mite. The small punctures of the pupal integument are difficult to detect but, by vital staining with trypan blue, the wounds can be visualised. The ultrastructure of the pupal wounds, the bacterial colonies and the scarring process are documented by a series of scanning electron micrographs.
Asunto(s)
Bacterias/ultraestructura , Abejas/microbiología , Abejas/parasitología , Ácaros , Animales , Bacterias/crecimiento & desarrollo , Abejas/crecimiento & desarrollo , Abejas/ultraestructura , Femenino , Bacterias Grampositivas/crecimiento & desarrollo , Bacterias Grampositivas/ultraestructura , Hemocitos/ultraestructura , Interacciones Huésped-Parásitos , Metamorfosis Biológica , Microscopía Electrónica de Rastreo , Muda , Pupa/crecimiento & desarrollo , Pupa/microbiología , Pupa/parasitología , Pupa/ultraestructuraRESUMEN
Trypanosoma cruzi populations are characterized by diverse morphology, heterogeneous biological behavior, high genetic variability, and distinctly different clinical courses. The first objective of this work was to characterize different strains of T. cruzi with various molecular markers [simple-sequence-repeat PCR, randomly amplified polymorphic DNA (RAPD)-PCR, mini-exon genes]. All examined strains could be divided into two major lineages. Only one strain showed a different banding pattern in RAPD-PCR, which could be a further indication of the existence of a third lineage. The second aim was to examine the biological behavior of the different strains. Two animal models, Calomys callosus and Mus musculus, were infected. The results provide strong evidence that the biological behavior of the strains is not only lineage-specific. It appears that all factors, such as the infecting strain belonging to a certain lineage, the predominant morphological form of the isolate, and the immune response of the respective infected host, play an important role in the course of this infection.
Asunto(s)
Ratones/parasitología , Muridae/parasitología , Parasitemia/fisiopatología , Trypanosoma cruzi/genética , Animales , Enfermedad de Chagas/fisiopatología , ADN Protozoario/genética , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Geografía , Humanos , Reacción en Cadena de la Polimerasa , Especificidad de la Especie , Trypanosoma cruzi/crecimiento & desarrollo , Trypanosoma cruzi/aislamiento & purificaciónRESUMEN
The Drosophila Dmblm locus is a homolog of the human Bloom syndrome gene, which encodes a helicase of the RECQ family. We show that Dmblm is identical to mus309, a locus originally identified in a mutagen-sensitivity screen. One mus309 allele, which carries a stop codon between two of the helicase motifs, causes partial male sterility and complete female sterility. Mutant males produce an excess of XY sperm and nullo sperm, consistent with a high frequency of nondisjunction and/or chromosome loss. These phenotypes of mus309 suggest that Dmblm functions in DNA double-strand break repair. The mutant Dmblm phenotypes were partially rescued by an extra copy of the DNA repair gene Ku70, indicating that the two genes functionally interact in vivo.
Asunto(s)
Antígenos Nucleares , ADN Helicasas/genética , ADN Helicasas/fisiología , Proteínas de Unión al ADN/genética , Drosophila melanogaster/fisiología , Proteínas Nucleares/genética , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/fisiología , Alelos , Sustitución de Aminoácidos , Animales , Síndrome de Bloom/genética , Rotura Cromosómica , Daño del ADN , Reparación del ADN , Proteínas de Unión al ADN/fisiología , Drosophila melanogaster/enzimología , Drosophila melanogaster/genética , Femenino , Fertilidad , Genes de Insecto , Prueba de Complementación Genética , Marcadores Genéticos , Autoantígeno Ku , Masculino , Mutagénesis Insercional , Mutación , No Disyunción Genética , Proteínas Nucleares/fisiología , Fenotipo , RecQ Helicasas , Recombinación Genética , Eliminación de Secuencia , Espermatozoides/fisiología , Transgenes , Cromosoma Y/genéticaRESUMEN
Combinations of lactococcal strains from various origins with divers properties were developed as new starters for new dairy products. Flavour formation by such tailor-made cultures was studied. In some cases, a strongly enhanced flavour was observed. For instance, the combination of B1157 and SK110 strains in milk resulted in a very strong chocolate-like flavour. B1157 produces only a moderate chocolate-like flavour, whereas SK110 alone fails to produce this flavour. Headspace gas chromatography results corroborate the organoleptic evaluations. High levels of branched-chain aldehydes were found when B1157 and SK110 were grown together. The enzyme activities involved in this pathway were studied; both strains contain transaminase activity. Although B1157 had a very high amino acid decarboxylating activity, its release of amino acids from milk protein was limited. SK110 was strongly limited in decarboxylating activity, although this strain is very active in proteolysis. By combining these strains, the substrates released by SK110 can directly be used by the other strain, resulting in the completion of the whole flavour-formation pathway. This opens new avenues for the preparation of tailor-made cultures.
Asunto(s)
Lactococcus lactis/metabolismo , Leche/química , Leche/microbiología , Gusto , Aldehídos/química , Aldehídos/metabolismo , Aminoácidos/análisis , Animales , Cacao , Carboxiliasas/metabolismo , Bovinos , Extractos Celulares , Cetoácidos/metabolismo , Lactococcus lactis/enzimología , Lactococcus lactis/crecimiento & desarrollo , Lactococcus lactis/fisiología , Leucina/metabolismo , Leche/metabolismo , Proteínas de la Leche/química , Proteínas de la Leche/metabolismo , Transaminasas/metabolismoRESUMEN
Although Drosophila is a wonderful model organism, there is one molecular arena where it lags far behind its yeast and mouse model counterparts. Reverse genetics, whereby a piece of DNA is integrated into a target gene such that the gene is disrupted or replaced, is not easy in Drosophila. As Engels explains in his provocative Perspective, this may be set to change with the description of a new method for reverse genetics in Drosophila (Rong and Golic). This new technique should ensure that Drosophila remains the darling of geneticists for many years to come.
Asunto(s)
Drosophila melanogaster/genética , Marcación de Gen , Genes de Insecto , Mutagénesis , Recombinación Genética , Animales , Daño del ADN , Reparación del ADN , Replicación del ADN , Elementos Transponibles de ADN , Femenino , Masculino , Reacción en Cadena de la PolimerasaRESUMEN
Diabetes mellitus generally results in an increased systemic fatty acid mobilization which can be associated with an increase in mitochondrial and peroxisomal beta-oxidation of fatty acids in selected tissues. The latter is usually accompanied by a concomitant increase in the tissue content of cytoplasmic fatty acid-binding protein (FABP) which functions in the intracellular translocation of fatty acids. It was previously found that in liver clofibrate-induced proliferation of peroxisomes and increase in FABP expression each are dependent on the induction by cytochrome P4504A1 -mediated (CYP4A1) formation of dicarboxylic acids. We studied whether peroxisome proliferation and an increase of FABP contents in liver, heart and kidney of streptozotocin-induced diabetic rats are also accompanied by an increase of CYP4A1 activity, as this would indicate a possible regulatory role for dicarboxylic acids in peroxisome proliferation and FABP induction in diabetic organs other than liver. In livers of the diabetic rat, a concomitant increase was observed of the activities of CYP4A1 and the peroxisomal key enzyme fatty acyl-CoA oxidase (FACO) and of the FABP content. In the diabetic heart FACO activity and FABP content also increased, but there was no induction of CYP4A1 activity. Conversely, in diabetic kidney there was no increase in FACO activity nor FABP content in spite of a marked induction of CYP4A1 activity. It is concluded that streptozotocin-induced diabetes leads to increased peroxisome proliferation and increased levels of FABP in both liver and heart, which only in liver is accompanied by an induction of the cytochrome P450 system. Consequently, it is not likely that dicarboxylic acids are involved in the induction of peroxisome proliferation in the heart.
Asunto(s)
Proteínas Portadoras/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Diabetes Mellitus Experimental/metabolismo , Riñón/metabolismo , Hígado/metabolismo , Microcuerpos/metabolismo , Proteína P2 de Mielina/metabolismo , Miocardio/metabolismo , Proteínas de Neoplasias , Proteínas del Tejido Nervioso , Acil-CoA Deshidrogenasa , Animales , Glucemia/análisis , Peso Corporal , Citocromo P-450 CYP4A , Sistema Enzimático del Citocromo P-450/análisis , Ácido Graso Desaturasas/metabolismo , Proteína de Unión a los Ácidos Grasos 7 , Proteínas de Unión a Ácidos Grasos , Masculino , Microsomas/metabolismo , Oxigenasas de Función Mixta/metabolismo , Ratas , Ratas Wistar , Distribución TisularRESUMEN
We have cloned a mutS homolog from Drosophila melanogaster called spellchecker1 (spel1) and have constructed spel1 mutant flies. MutS proteins promote the correction of DNA mismatches and serve important roles in DNA replication, recombination, and repair. The spel1 gene belongs to a subfamily of mutS first characterized by the MSH2 gene of yeast and which also includes hMSH2, one of the two major hereditary nonpolyposis colon cancer loci of humans. Like msh2 mutants in other species, we find that flies lacking the spel1 gene suffer a highly increased rate of instability in long runs of dinucleotide repeats when analyzed after 10-12 fly generations. Using a new assay, we have also discovered that mutations in spel1 decrease the stability of a dinucleotide repeat when it is copied into the site of a double-strand break during gene conversion. Contrary to the case in mammalian cells, spel1 deficiency does not affect tolerance of flies to a methylating agent nor does it affect resistance to gamma-irradiation.
Asunto(s)
Adenosina Trifosfatasas , Proteínas Bacterianas/genética , Proteínas de Unión al ADN , Proteínas de Drosophila , Drosophila melanogaster/genética , Proteínas de Escherichia coli , Genes de Insecto , Repeticiones de Microsatélite/genética , Proteínas Recombinantes/genética , Animales , Reparación del ADN , Replicación del ADN , Datos de Secuencia Molecular , Proteína MutS de Unión a los Apareamientos Incorrectos del ADN , Mutación , Recombinación Genética , Homología de Secuencia de Ácido NucleicoRESUMEN
Several eukaryotic homologs of the Escherichia coli RecQ DNA helicase have been found. These include the human BLM gene, whose mutation results in Bloom syndrome, and the human WRN gene, whose mutation leads to Werner syndrome resembling premature aging. We cloned a Drosophila melanogaster homolog of the RECQ helicase family, Dmblm (Drosophila melanogaster Bloom), which encodes a putative 1487-amino-acid protein. Phylogenetic and dot plot analyses for the RECQ family, including 10 eukaryotic and 3 prokaryotic genes, indicate Dmblm is most closely related to the Homo sapiens BLM gene, suggesting functional similarity. Also, we found that Dmblm cDNA partially rescued the sensitivity to methyl methanesulfonate of Saccharomyces cerevisiae sgs1 mutant, demonstrating the presence of a functional similarity between Dmblm and SGS1. Our analyses identify four possible subfamilies in the RECQ family: (1) the BLM subgroup (H. sapiens Bloom, D. melanogaster Dmblm, and Caenorhabditis elegans T04A11.6); (2) the yeast RECQ subgroup (S. cerevisiae SGS1 and Schizosaccharomyces pombe rqh1/rad12); (3) the RECQL/Q1 subgroup (H. sapiens RECQL/Q1 and C. elegans K02F3.1); and (4) the WRN subgroup (H. sapiens Werner and C. elegans F18C5.2). This result may indicate that metazoans hold at least three RECQ genes, each of which may have a different function, and that multiple RECQ genes diverged with the generation of multicellular organisms. We propose that invertebrates such as nematodes and insects are useful as model systems of human genetic diseases.
Asunto(s)
Adenosina Trifosfatasas/genética , ADN Helicasas/genética , Drosophila melanogaster/genética , Evolución Molecular , Secuencia de Aminoácidos , Animales , Síndrome de Bloom/genética , Supervivencia Celular , Clonación Molecular , ADN Helicasas/química , Humanos , Proteínas de Insectos/genética , Modelos Biológicos , Modelos Genéticos , Datos de Secuencia Molecular , Filogenia , Plásmidos/genética , Reacción en Cadena de la Polimerasa , RecQ Helicasas , Alineación de Secuencia , Supresión GenéticaRESUMEN
The complete structure of the cysteine proteinase (CP1) gene reveals two large 5' introns as well as a small third intron. Deletion studies have shown that null mutations for the locus are female sterile with partial male sterility as well as wing and pigmentation effects. Null alleles can be produced by either deletions to the left or deletions to the right of a P element insertion in the long second intron of the gene. A nearby phenylalanyl tRNA synthetase gene (Pts) was also identified.