RESUMEN
Dickeya dianthicola has caused an outbreak of blackleg and soft rot of potato in the eastern half of the United States since 2015. To investigate genetic diversity of the pathogen, a comparative analysis was conducted on genomes of D. dianthicola strains. Whole genomes of 16 strains from the United States outbreak were assembled and compared with 16 previously sequenced genomes of D. dianthicola isolated from potato or carnation. Among the 32 strains, eight distinct clades were distinguished based on phylogenomic analysis. The outbreak strains were grouped into three clades, with the majority of the strains in clade I. Clade I strains were unique and homogeneous, suggesting a recent incursion of this strain into potato production from alternative hosts or environmental sources. The pangenome of the 32 strains contained 6,693 genes, 3,377 of which were core genes. By screening primary protein subunits associated with virulence from all U.S. strains, we found that many virulence-related gene clusters, such as plant cell wall degrading enzyme genes, flagellar and chemotaxis related genes, two-component regulatory genes, and type I/II/III secretion system genes, were highly conserved but that type IV and type VI secretion system genes varied. The clade I strains encoded two clusters of type IV secretion systems, whereas the clade II and III strains encoded only one cluster. Clade I and II strains encoded one more VgrG/PAAR spike protein than did clade III. Thus, we predicted that the presence of additional virulence-related genes may have enabled the unique clade I strain to become predominant in the U.S. outbreak.
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Solanum tuberosum , Dickeya , Brotes de Enfermedades , Enfermedades de las Plantas , Estados UnidosRESUMEN
An outbreak of blackleg and soft rot of potato, caused primarily by the bacterial pathogen Dickeya dianthicola, has resulted in significant economic losses in the northeastern United States since 2015. The spread of this seedborne disease is highly associated with seed distribution; therefore, the pathogen likely spread with seed tubers. To describe the blackleg epidemic and track inoculum origins, a total of 1,183 potato samples were collected from 11 states associated with blackleg outbreak from 2015 to 2019. Of these samples, 39.8% tested positive for D. dianthicola. Seventeen isolates of D. dianthicola were recovered from these samples and the genetic diversity of these isolates was examined. Fingerprinting with BOX-A1R-based repetitive extragenic palindromic PCR and phylogenetic analysis based on sequences of the 16S rRNA and gapA genes indicated that D. dianthicola isolates were divided into three genotypes, denoted types I, II, and III. Ninety-five percent of samples from Maine were type I. Type II was found in Maine only in 2015 and 2018. Type II was present throughout the 5 years in some states at a lower percentage than type I. Type III was found in Pennsylvania, New Jersey, and Massachusetts, but not in Maine. Therefore, type I appears to be associated with Maine, but type II appeared to be distributed throughout the northeastern United States. The type II and rarer type III strains were closer to the D. dianthicola type strain isolated from the United Kingdom. This work provides evidence that the outbreak of blackleg of potato in the northeastern United States was caused by multiple strains of D. dianthicola. The geographic origins of these strains remain unknown.
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Solanum tuberosum , Dickeya , Brotes de Enfermedades , Genotipo , Geografía , Filogenia , Enfermedades de las Plantas , ARN Ribosómico 16S/genética , Estados UnidosRESUMEN
Potato common scab is an important soilborne disease worldwide that can significantly reduce the quality and economic values of potato. The disease is caused by multiple species of Streptomyces, which are not well controlled due to lack of effective strategies. Streptomyces galilaeus has been recently identified as a dominant species causing potato common scab in Inner Mongolia, China. This study was focused on screening and characterizing antagonists for biological control against pathogenic S. galilaeus. Bacterial strain PBSH9 was isolated from a potato tuber. PBSH9 was identified as a Streptomyces sp. on the basis of morphological, physiological, and biochemical characteristics, as well as DNA sequence analysis. PBSH9 inhibited S. galilaeus with a diameter of inhibitory zone of 19.8 mm on agar plates. The extracellular filtrate of PBSH9 also inhibited S. galilaeus growth with a diameter of inhibition zone of 10.0 mm. Furthermore, PBSH9 promoted potato sprouting and emergence. Disease control was up to 81.88% in greenhouse trials, and from 47.64 to 73.97% in 3-year field trials. Among the tested inoculation methods, seed treatment was more effective than soil drenching for PBSH9 application. PBSH9 not only effectively controlled potato common scab but also increased potato growth. Thus, it can be a potential candidate for biocontrol agent.
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Solanum tuberosum , Streptomyces , China , Enfermedades de las PlantasRESUMEN
American ginseng (Panax quinquefolius L.) is a highly valuable herb widely used for medicinal treatments. Its pharmacologically important compounds are the ginsenosides, which are secondary metabolites in American ginseng root. The concentrations of ginsenoside in roots can be changed by fungal infection, but it is unclear what specific root tissues are impacted and whether the change is systemic. In this study, American ginseng roots were inoculated with two fungal pathogens (Fusarium solani or F. oxysporum) and the levels of six ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1) were then measured in the phloem and xylem around the discolored lesions and adjacent healthy areas of the root. Results indicated that the growth of Fusarium spp. was strictly limited to phloem, and correspondingly the ginsenoside concentration was only altered in this infected phloem. The concentration of Rg1, Rd, and Rc significantly changed in phloem tissues where F. solani was inoculated, while only Rg1 and Rd changed significantly after F. oxysporum inoculation. However, no changes of any ginsenoside occurred in either xylem or phloem tissue adjacent to the inoculation point. In addition, when two Fusarium spp. were grown on ginsenoside-amended Czapek medium, the majority of ginsenosides were depleted. Therefore, pathogenic Fusarium spp. may reduce ginsenoside levels by consuming them.
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Fusarium/fisiología , Ginsenósidos/metabolismo , Panax/metabolismo , Panax/microbiología , Enfermedades de las Plantas/microbiología , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Ginsenósidos/químicaRESUMEN
Fistular onion stalk is used as a traditional herbal medicine, and its extract exhibits certain beneficial effects on cardiovascular disease. In this study, the effects of fistular onion stalk extract on the pathological features, circulating inflammatory cytokines, local renin-angiotensin-aldosterone system (RAAS) and signaling pathway activities were examined using an in vivo model of atherosclerosis. Atherosclerosis of the aorta was induced by loading Sprague Dawley rats with a high-fat diet and vitamin D2. Fistular onion stalk extract administration began five weeks after the induction of atherosclerosis and continued for 12 weeks. Rats treated with fistular onion stalk extract showed a significant reduction in the pathological region compared with the vehicle-treated controls. Inhibition of atherosclerosis was associated with preservation of the vascular wall and immune cell infiltration. The extract also reduced the levels of the local inflammatory cytokines interleukin (IL)-1ß, IL-6, monocyte chemoattractant protein-1 and tumor necrosis factor-α. Furthermore, the extract downregulated the local activity of the RAAS. In addition, extract treatment inhibited several inflammatory signaling pathways by preventing phosphorylation, including the nuclear factor κB, Janus kinase/signal transducers and activators of transcription and mitogen-activated protein kinase pathways. These data indicate that fistular onion stalk extract may be useful for the attenuation of atherosclerosis, and the mechanism includes the regulation of the local inflammatory response.
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CONTEXT: Living in a prediabetes state significantly increases a patient's risk for both diabetes and cardiovascular disease. Tianqi capsule, containing 10 Chinese herbal medicines, is used in China for the treatment of type 2 diabetes mellitus (T2DM). OBJECTIVE: The purpose of this study was to assess whether Tianqi prevented T2DM in subjects with impaired glucose tolerance (IGT) over the course of a 12-month treatment. METHODS: Individuals with IGT were randomly allocated in a double-blind manner to receive Tianqi (n = 210) or a placebo (n = 210) for 12 months. Oral glucose tolerance tests were conducted every 3 months to assess the development of diabetes or restoration to normal glucose tolerance. All subjects received the same lifestyle education. The primary endpoint was the conversion of IGT to T2DM. Body weight and body mass index were observed. Adverse effects were monitored. RESULTS: Of the 420 enrolled subjects with IGT, 389 completed the trial (198 in the Tianqi group and 191 in the placebo group). At the end of the 12-month trial, 36 subjects in the Tianqi group (18.18%) and 56 in the placebo group (29.32%) had developed diabetes (P = .01). There was a significant difference in the number of subjects who had normal glucose tolerance at the end of the study between the Tianqi and placebo groups (n = 125, 63.13%, and n = 89, 46.60%, respectively; P = .001). Cox's proportional hazards model analysis showed that Tianqi reduced the risk of diabetes by 32.1% compared with the placebo. No severe adverse events occurred in the trial. There were no statistical differences in body weight and body mass index changes between the Tianqi group and the placebo group during the 12-month trial. CONCLUSIONS: Treatment with a Tianqi capsule for 12 months significantly decreased the incidence of T2DM in subjects with IGT, and this herbal drug was safe to use.
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Diabetes Mellitus Tipo 1/prevención & control , Medicamentos Herbarios Chinos/uso terapéutico , Intolerancia a la Glucosa/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Estado Prediabético/tratamiento farmacológico , Adulto , Anciano , Glucemia , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Progresión de la Enfermedad , Método Doble Ciego , Femenino , Intolerancia a la Glucosa/prevención & control , Prueba de Tolerancia a la Glucosa , Humanos , Estilo de Vida , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
A novel formulation based on nanovesicles system for rapid-onset sublingual delivery of hydrophilic drug (sodium tanshinone IIA sulfonate, STS) was investigated. The nanovesicles system was composed of 1.5% soybean lecithin, 6% propylene glycol, and penetration enhancers (1% sodium dodecyl sulfate and 0.03% hyaluronan acid). The STS-loaded nanovesicles with an average diameter of 133 ± 9.04 nm and high entrapment efficiency of 85.65 ± 3.89% were characterized. The effects of permeation enhancers on the penetration of STS formulations were investigated using Franz diffusion cells in vitro, showing 86.1-235.8 times higher permeation rate than that of normal STS solution. The rapid symptom relief effect of the nanovesicles system on acute myocardial infarction rabbits was evaluated by in vivo study, ST-segment deviation(S and T wave abnormality in electrocardiogram) was attenuated markedly and rapidly within 5 min, infarct size of heart was significantly reduced and the biochemical indicators were substantially decreased, compared with the control groups (p < 0.05). This study provided a promising tool for the future sublingual delivery of hydrophilic compounds with the noninvasive and rapid onset clinical effect.
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Portadores de Fármacos/química , Medicamentos Herbarios Chinos/administración & dosificación , Medicamentos Herbarios Chinos/uso terapéutico , Infarto del Miocardio/tratamiento farmacológico , Fenantrenos/administración & dosificación , Fenantrenos/uso terapéutico , Administración Sublingual , Animales , Medicamentos Herbarios Chinos/farmacocinética , Corazón/efectos de los fármacos , Lecitinas/química , Masculino , Infarto del Miocardio/patología , Miocardio/patología , Nanoestructuras/química , Fenantrenos/farmacocinética , Propilenglicol/química , Conejos , Glycine max/químicaRESUMEN
BACKGROUND AND AIM: Chinese traditional medical science is generally used as a therapeutic method against functional dyspepsia (FD) in China. Although great effort is made to understand the pharmaceutical mechanisms of Chinese traditional medicine, such as typical traditional Chinese medicine, Wei Kangning, there are still many mysteries to be uncovered. METHODS: The model of FD was established by stimulating rats via tail damping and the rats were treated with traditional Chinese medicine, Wei Kangning. The proteins of the rat gastrointestinal tissues were extracted and run by 2-DE, then the differential proteins were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry and validated with Western blotting or fluorescent quantitation polymerase chain reaction. RESULTS: A total of 228 unique proteins in FD model rats were detected with significant changes in their expression levels corresponding with traditional Chinese medicine, Wei Kangning, administration. Twenty-eight of these proteins were identified, which are involved in many biological functions, such as organism antioxidant enzymes, energy metabolism, glutathione S-transferase, pi2, superoxide dismutase 2 and alpha-enolase and so on. CONCLUSIONS: These proteomic results presented therefore provide additional support to the hypothesis that glutathione S-transferase, pi2, superoxide dismutase 2, α-enolase and voltage-dependent anion channel are the targets of FD treated with traditional Chinese medicine, Wei Kangning.
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Medicamentos Herbarios Chinos/farmacología , Dispepsia/tratamiento farmacológico , Intestinos/efectos de los fármacos , Proteómica , Estómago/efectos de los fármacos , Estrés Psicológico/complicaciones , Animales , Western Blotting , Modelos Animales de Enfermedad , Dispepsia/etiología , Dispepsia/metabolismo , Dispepsia/fisiopatología , Electroforesis en Gel Bidimensional , Mucosa Gástrica/metabolismo , Motilidad Gastrointestinal/efectos de los fármacos , Gutatión-S-Transferasa pi/metabolismo , Mucosa Intestinal/metabolismo , Intestinos/fisiopatología , Fosfopiruvato Hidratasa/metabolismo , Proteómica/métodos , Ratas , Ratas Wistar , Reacción en Cadena en Tiempo Real de la Polimerasa , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Estómago/fisiopatología , Superóxido Dismutasa/metabolismo , Canales Aniónicos Dependientes del Voltaje/efectos de los fármacos , Canales Aniónicos Dependientes del Voltaje/metabolismoRESUMEN
AIM OF THE STUDY: To investigate the cardioprotective potential of Syringa pinnatifolia Hems1. var. alashanensis essential oil (SPEO) against experimental acute myocardial ischemia (AMI), hydrogen peroxide (H(2)O(2))-induced myocyte injury and activities against hypoxia and platelet aggregation. MATERIALS AND METHODS: Wistar rats, Kunming mice and primary cultured rat neonatal myocytes were used in this study. AMI in rats was induced by ligation of the left anterior descending (LAD) coronary artery, and deviation of ST-segment, as well as changes of myocardial enzyme activities were observed. Hypoxia test in Kunming mice was performed to evaluate the effect of SPEO against hypoxia. The protective effect of SPEO on H(2)O(2)-induced cell injury was evaluated in terms of cell viability assay. The in vitro effect of SPEO against platelet aggregation was studied using adenosine 5'-diphosphate (ADP) as agonist. RESULTS: Administration of SPEO reduced deviation of ST-segment, decreased the levels of lactate dehydrogenase (LDH), creatine kinase (CK) and Troponin T (TnT) while increased the activities of superoxide dismutase (SOD). The protective role of SPEO was further confirmed by histopathological examination. In the hypoxia test, both 8 and 32 mg/kg of SPEO could prolong survival time of mice under hypoxia condition. At the meantime SPEO showed remarkable protective effect on cultured rat myocyte death induced by H(2)O(2). SPEO also inhibited ADP-induced rat platelet aggregation by 47.4%, 37.0% and 32.9% at the dose of 5, 2.5 and 1.25 microg/mL, respectively. CONCLUSIONS: These results suggest that SPEO possessing activities against hypoxia, oxidative stress and platelet aggregation has a significant protective effect against experimental myocardial ischemia.
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Fármacos Cardiovasculares/uso terapéutico , Isquemia Miocárdica/tratamiento farmacológico , Daño por Reperfusión Miocárdica/prevención & control , Miocardio/patología , Aceites Volátiles/uso terapéutico , Agregación Plaquetaria/efectos de los fármacos , Syringa/química , Animales , Fármacos Cardiovasculares/farmacología , Muerte Celular/efectos de los fármacos , Creatina Quinasa/metabolismo , Modelos Animales de Enfermedad , Electrocardiografía/efectos de los fármacos , Femenino , Peróxido de Hidrógeno , Hipoxia/tratamiento farmacológico , Hipoxia/mortalidad , L-Lactato Deshidrogenasa/metabolismo , Masculino , Ratones , Ratones Endogámicos , Células Musculares/efectos de los fármacos , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/patología , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/patología , Miocardio/metabolismo , Aceites Volátiles/farmacología , Fitoterapia , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Tallos de la Planta , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismo , Troponina T/metabolismoRESUMEN
OBJECTIVE: To investigate the effects of extract of Bulbus Allii Caespitosi on cardiocyte viability of swines with myocardial reperfusion injury by analyzing the 18F-fluorodeoxyglucose ((18)F-FDG) position emission tomography (PET) imaging. METHODS: Twenty-four swines were randomly divided into sham-operated group, untreated group, trimethazine group and extract of Bulbus Allii Caespitosi group. Myocardial reperfusion injury was induced by plugging the anterior descending coronary artery of swine with sacculus. Bulbus Allii Caespitosi or trimetazidine was given twice daily for 28 days. Then myocardial perfusion was detected with (18)F-FDG PET/CT and the radioactivity distribution was evaluated. RESULTS: Compared with the untreated group, Bulbus Allii Caespitosi and trimetazidine could improve the activity of myocardial cells after myocardial infarction (P<0.01), and there were no significant differences between Bulbus Allii Caespitosi and trimetazidine (P>0.05). CONCLUSION: Bulbus Allii Caespitosi can improve myocardial metabolism after ischemia and reperfusion in swines.
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Daño por Reperfusión Miocárdica/tratamiento farmacológico , Miocardio/metabolismo , Extractos Vegetales/farmacología , Animales , Fluorodesoxiglucosa F18 , Infarto del Miocardio/fisiopatología , Daño por Reperfusión Miocárdica/metabolismo , Tomografía de Emisión de Positrones , PorcinosRESUMEN
OBJECTIVE: To explore the mechanism of Tiaozhong Granule (TZG), a compound traditional Chinese herbal medicine, in treating rats with mixed reflux esophagitis. METHODS: Fifty-eight SD rats were randomly divided into untreated group (n=12), sham-operated group (n=10), TZG-treated group (n=12), Banxia Xiexin Decoction (BXXXD)-treated group (n=12) and cisapride-treated group (n=12). Mixed reflux esophagitis was induced by esophago-duodenum end-to-side anastomosis. Four weeks later, the rats were orally administered twice daily for 12 days. Pathological changes of esophagus mucous membrane were observed by using HE staining. The expressions of proliferating cell nuclear antigen (PCNA) and p53 in the esophagus tissue were detected by immunohistochemical SABC method. Spectrophotometric method was used to detect the content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum. RESULTS: Compared with the untreated group, pathological changes of esophagus mucous membrane were relieved in different degrees in TZG-treated group, BXXXD-treated group and cisapride-treated group. Content of MDA and expressions of PCNA and p53 were obviously decreased in the three treated groups (P<0.01), and the activities of SOD and GSH-Px were significantly increased in the three treated groups (P<0.05, P<0.01). TZG had better effects than cisapride in decreasing the content of MDA and increasing the activities of SOD and GSH-Px (P<0.05). TZG was better in aspect of reducing the expressions of PCNA and p53 than BXXXD and cisapride tablets (P<0.05). CONCLUSION: Tiaozhong Granule can treat mixed reflux esophagitis in rats, and its action mechanisms may be associated with decreasing the expressions of PCNA and p53 in esophagus mucous membrane, reducing the content of MDA and increasing the activities of SOD and GSH-Px in serum.
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Medicamentos Herbarios Chinos/uso terapéutico , Esofagitis Péptica/tratamiento farmacológico , Esófago/efectos de los fármacos , Membrana Mucosa/efectos de los fármacos , Fitoterapia , Animales , Esófago/metabolismo , Femenino , Masculino , Membrana Mucosa/metabolismo , Antígeno Nuclear de Célula en Proliferación/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Superóxido Dismutasa/metabolismo , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
OBJECTIVE: To observe the protective effect of Huaxia shallot preparation on human umbilical vein endothelial cell (HUVEC) injury induced by oxidized low density lipoprotein (Ox-LDL) in vitro. METHODS: Ox-LDL was prepared and identified, and HUVECs were cultured. After 2-hour intervention of different drugs and 24-hour following intervention of Ox-LDL, the number of HUVECs was observed by phase contrast optical microscope and the activity of the HUVECs was observed by methyl thiazolyl tetrazolium (MTT) technique. Superoxide dismutase (SOD) activity and nitric oxide (NO) content were assayed by respective kit. The protein expressions and mRNA levels of peroxisome proliferators activated receptor gamma(PPAR-gamma) and endothelial nitric oxide synthase (eNOS) were measured by western blot technique and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Ox-LDL could increase the apoptosis rate of the HUVECs and decrease the NO release as compared with the blank control group (P<0.05). These effects induced by Ox-LDL were all significantly inhibited by Huaxia shallot preparation. It could up-regulate the protein expressions and mRNA levels of PPAR-gamma and eNOS significantly (P<0.05). Huaxia shallot preparation could decrease the apoptosis rate of the HUVECs. CONCLUSION: Ox-LDL may be involved in the initiation and progression of atherosclerosis by injuring the endothelial cells directly and may cause the endothelial dysfunction. Huaxia shallot preparation can protect against Ox-LDL induced endothelial cell injury by up-regulating the protein expressions and mRNA levels of PPAR-gamma and eNOS. It suggests that Huaxia shallot preparation may play a role in the prevention and treatment of cardiovascular disease.
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Antioxidantes/farmacología , Medicamentos Herbarios Chinos/farmacología , Células Endoteliales/patología , Lipoproteínas LDL/farmacología , Chalotes/química , Células Cultivadas , Células Endoteliales/efectos de los fármacos , Humanos , Óxido Nítrico Sintasa de Tipo III/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Estrés Oxidativo/efectos de los fármacos , PPAR gamma/genética , PPAR gamma/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Venas Umbilicales/citologíaRESUMEN
Formation of calcified tissues is a well regulated process. In dentin, the odontoblasts synthesize several biomolecules that function as nucleators or inhibitors of mineralization. To identify genes that are odontoblast-specific, a subtractive hybridization technique was employed that resulted in the identification of a previously undescribed novel gene synthesized by the odontoblasts. Based on the nomenclature in our laboratory, this gene has been named dentin matrix protein 4 (DMP4). The protein encoded by mouse DMP4 cDNA contained 579 amino acids, including a 26-amino acid signal peptide. Analysis of the protein sequence demonstrated the presence of a Greek key calcium-binding domain and one conserved domain of unknown function in all the species examined thus far. Calcium binding property was confirmed by (45)Ca binding assays and the corresponding change in conformation by far-ultraviolet circular dichroism. Northern analysis demonstrated high expression levels of a single 3-kb mRNA transcript in tooth, whereas low expression levels were detected in other tissues. In situ hybridization analysis showed high expression levels of DMP4 in odontoblasts and low levels in osteoblasts and ameloblasts during tooth development. Gain and loss of function experiments demonstrated that DMP4 had the potential to differentiate mesenchymal precursor cells into functional odontoblast-like cells.
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Proteínas de Unión al Calcio/metabolismo , Diferenciación Celular/fisiología , Proteínas de la Matriz Extracelular/metabolismo , Regulación de la Expresión Génica/fisiología , Células Madre Mesenquimatosas/metabolismo , Odontoblastos/metabolismo , Ameloblastos/citología , Ameloblastos/metabolismo , Animales , Calcio/metabolismo , Proteínas de Unión al Calcio/genética , Línea Celular Transformada , Dicroismo Circular , ADN Complementario/genética , Proteínas de la Matriz Extracelular/genética , Células Madre Mesenquimatosas/citología , Ratones , Odontoblastos/citología , Especificidad de Órganos/fisiología , Osteoblastos/citología , Osteoblastos/metabolismo , Unión Proteica/genética , Señales de Clasificación de Proteína/genética , Estructura Terciaria de Proteína/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Diente/citología , Diente/metabolismoRESUMEN
Odontoblasts and osteoblasts are two among the myriads of cell types present in the craniofacial complex. Both have a common ectomesenchymal origin and secrete macromolecules that are necessary for the formation of dentin and alveolar bone via matrix-mediated mechanisms. The mineralized matrices of bone and dentin differ in morphology and function but several mineral associated proteins, formerly thought to be tissue specific, have been found to be common in both tissues. To decipher the complex molecular mechanisms involved in mineralized dentin formation, the suppressive subtraction hybridization (SSH) approach has been used to identify the genes expressed by polarized odontoblasts. Employing SSH, 187 cDNA clones were identified from the subtracted cDNA library. Many of these genes have not been previously reported to be expressed by terminally differentiated odontoblasts. Genes were classified into seven groups based on the predicted function of the encoded proteins: extracellular matrix; cytoskeletal components, molecules involved in adhesion and cell-cell interaction; metabolic enzymes, transporters, ion channels; protein processing, protein transport and protein folding molecules; nuclear proteins (transcription factors, DNA processing enzymes); signaling molecules and genes of yet unknown function. Northern blot and in situ hybridization analysis performed for five putative novel genes and one new isoform of amelogenin revealed differential expression levels in the osteoblasts, ameloblasts and the odontoblasts of the developing rat molars. Some of the known genes isolated from this enriched pool were the cleavage products of dentin sialophosphoprotein (DSPP) namely, phosphophoryn (PP) and dentin sialoprotein (DSP). Interestingly amelogenin, ameloblastin and enamelin were also expressed in the odontoblasts during dentin formation.