RESUMO
AIMS: Cervical cancer incidence and mortality rates are approximately 55% higher in the Rio Grande Valley (RGV) along the Texas-Mexico border compared with the average rates in the US. Our aim was to improve cervical cancer prevention efforts in the RGV through a comprehensive multilevel intervention initiative focused on community education, patient navigation, and training of local providers. METHODS: We initiated a program in the RGV which consisted of (1) community education, (2) patient navigation, and (3) a training/mentoring program for local medical providers including hands-on training courses coupled with telementoring using Project ECHO® (Extension for Community Health Outcomes). We assessed the number of women undergoing cervical cancer screening, diagnosis, and treatment at three participating clinics caring for underserved women in the region. RESULTS: From November 2014 to October 2018, 14,846 women underwent cervical cancer screening. A total of 2030 (13.7%) women underwent colposcopy for abnormal results (179% increase over baseline) and 453 women underwent loop electrosurgical excision procedures (LEEPs) for treatment of cervical dysplasia. Invasive cancer was diagnosed in 39 women who were navigated to a gynecologic oncologist for treatment. Seven local medical providers were trained to perform colposcopy and/or LEEP. Project ECHO telementoring videoconferences were held every 2 weeks for a total 101 sessions with an average of 22 participants per session and a total of 180 patient cases presented and discussed. CONCLUSIONS: Our program led to a large number of women undergoing diagnosis and treatment of cervical dysplasia in the RGV. If sustained, we anticipate these efforts will decrease cervical cancer rates in the region. The program is currently being expanded to additional underserved areas of Texas and globally to low- and middle-income countries.
Assuntos
Navegação de Pacientes , Displasia do Colo do Útero , Neoplasias do Colo do Útero , Feminino , Humanos , Masculino , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/prevenção & controle , Texas/epidemiologia , México/epidemiologia , Detecção Precoce de CâncerRESUMO
It has been recognized that numerous synthetic compounds like Bisphenol A (BPA) and nonylphenols (NP) are present in effluents from wastewater treatment plants (WWTP) at levels of parts per billion (µg L(-1)) or even parts per trillion (ng L(-1)) with a high potential to cause endocrine disruption in the aquatic environment. Constructed wetlands (CW) are a cost-effective wastewater treatment alternative with promising performance to treat these afore mentioned compounds. This research was aimed to evaluate the efficacy of CW treatment of WWTP effluent for mitigating the effects endocrine disrupting compounds (EDCs). This research goal was accomplished by (1) quantifying the removal of BPA and NP in CWs; (2) isolating CW fungal strains and testing for laccase production; and (3) performing endocrine disruption (reproduction) bioassays using the fruit fly Drosophila melanogaster. Three pilot scale horizontal subsurface flow constructed wetlands (HSSF-CW) were operated for eight weeks: one planted with Phragmites australis; one planted with Heliconia psitacorum; and one unplanted. The Heliconia CW showed a removal efficiency of 73.3(± 19%) and 62.8(± 20.1%) for BPA and NP, respectively; while the Phragmites CW demonstrated a similar removal for BPA (70.2 ± 27%) and lower removal efficiency for NP 52.1(± 37.1%).The unplanted CW achieved 62.2 (± 33%) removal for BPA and 25.3(± 37%) removal for NP. Four of the eleven fungal strains isolated from the Heliconia-CW showed the capacity to produce laccase. Even though complete removal of EDCs was not achieved by the CWs, the bioassay confirmed a significant improvement (p < 0.05) in fly viability for all CWs, with Heliconia sp. being the most effective at mitigating adverse effects on first and second generational reproduction. This study showed that a CW planted with a native Heliconia sp. CW demonstrated a higher removal of endocrine disrupting compounds and better mitigation of reproductive disruption in the bioassay.
Assuntos
Compostos Benzidrílicos/análise , Fenóis/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Áreas AlagadasRESUMO
The potential of enhancing water uses using soil aquifer treatment (SAT) is an interesting alternative for tropical regions, limited only by lack of knowledge on its performance in local conditions and the feasibility of adapting this technology. A SAT pilot study was conducted to analyze the phenomena associated with the transformation of organic matter (OM) from domestic wastewater. Chemically enhanced primary effluent collected at the Cañaveralejo wastewater treatment plant (Cali, Colombia) was used to feed pilot-scale SAT units at a rate of 1.25 m.d⻹. Dissolved organic carbon (DOC) removal in a 5.0 m length and 0.1 m diameter column packed with sand was 64.4%, while a similar column packed with a Mollisol soil from Valle del Cauca region yielded 56.2%. Oxygen availability was an important factor in OM degradation, given that the sand column degraded OM aerobically and the soil column degraded OM under oxic as well as anoxic conditions. SAT acted as a reliable barrier for DOC in tropical conditions. Nevertheless, operational problems such as clogging indicated that probably Mollisol soil may not be the suitable for SAT or that this particular effluent requires further pre-treatment before SAT.
Assuntos
Água Subterrânea , Compostos Orgânicos/isolamento & purificação , Clima Tropical , Águas Residuárias , Purificação da Água/métodos , Projetos PilotoRESUMO
Magnetostatic (dipolar) interactions between nanoparticles promise to open new ways to design nanocrystalline magnetic materials and devices if the collective magnetic properties can be controlled at the nanoparticle level. Magnetic dipolar interactions are sufficiently strong to sustain magnetic order at ambient temperature in assemblies of closely-spaced nanoparticles with magnetic moments of ≥ 100â µ(B). Here we use electron holography with sub-particle resolution to reveal the correlation between particle arrangement and magnetic order in self-assembled 1D and quasi-2D arrangements of 15â nm cobalt nanoparticles. In the initial states, we observe dipolar ferromagnetism, antiferromagnetism and local flux closure, depending on the particle arrangement. Surprisingly, after magnetic saturation, measurements and numerical simulations show that overall ferromagnetic order exists in the present nanoparticle assemblies even when their arrangement is completely disordered. Such direct quantification of the correlation between topological and magnetic order is essential for the technological exploitation of magnetic quasi-2D nanoparticle assemblies.
Assuntos
Magnetismo , Nanopartículas Metálicas/química , Cobalto/química , Campos Magnéticos , Nanopartículas Metálicas/ultraestruturaRESUMO
Whole-cell immunofluorescent antibody (IFA) tests for detection of anti-Bartonella henselae immunoglobulin (Ig) G are commonly used to diagnose cat-scratch disease (CSD). The need to cultivate B. henselae in Vero cells for antigen preparation and the absence of routinely applied IFA assays for IgM constitute the major disadvantages of this form of test. We describe the results of an enzyme immunoassay (EIA) for IgM and IgG that used N-lauroyl-sarcosine-insoluble outer membrane antigens from agar-grown B. henselae performed in 84 patients with definite CSD (regional lymphadenitis, cat contact, and > or =1 confirmatory test: polymerase chain reaction, skin test, or B. henselae culture). Although this method has been used as a diagnostic tool in several case reports, it has not previously been evaluated in a large study of definitively proven CSD cases. Results of this study indicate that the EIA described herein can play an important role in the serodiagnosis of CSD, although improvement of the sensitivity, particularly that of the IgM, would be desirable.
Assuntos
Doença da Arranhadura de Gato/diagnóstico , Ensaios Enzimáticos Clínicos/métodos , Técnicas Imunoenzimáticas/métodos , Reação em Cadeia da Polimerase/métodos , Adolescente , Adulto , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Bartonella henselae/imunologia , Criança , Pré-Escolar , DNA Bacteriano/genética , Feminino , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Lactente , MasculinoRESUMO
Diagnosis of cat-scratch disease (CSD) by polymerase chain reaction (PCR) of lymph node fineneedle aspiration (FNA) and primary lesion specimens can be difficult owing to the minute amount of available material. A PCR assay specifically suited to test these specimens was developed. First, small-quantity (10 microL) samples were prepared from 17 CSD-positive and 16 CSD-negative specimens, and DNA extraction and amplification from these samples were compared using 3 methods. Sensitivity and specificity of PCR were 100% using material collected on glass microscope slides and by using Qiagen (Hilden, Germany) columns for DNA extraction. Then, this method was used to test 11 archival glass microscope slides of FNA (7 malignant neoplasms, 4 undiagnosed lymphadenitis) and 2 primary lesion specimens. Two of the 4 lymphadenitis samples and the 2 primary lesion specimens were PCR positive. The technique presented could facilitate CSD diagnosis from a wider range of clinical samples.
Assuntos
Bartonella henselae/isolamento & purificação , Doença da Arranhadura de Gato/diagnóstico , Reação em Cadeia da Polimerase/métodos , Bartonella henselae/genética , Biópsia por Agulha , Doença da Arranhadura de Gato/microbiologia , Doença da Arranhadura de Gato/patologia , Criança , DNA Bacteriano/isolamento & purificação , Humanos , Linfonodos/patologia , Pessoa de Meia-Idade , Sensibilidade e EspecificidadeRESUMO
El objetivo del presente trabajo fue evaluar la prescripción analgésica en el servicio quirúrgico de ginecología como paso previo a la elaboración de protocolos orientados a mejorar su prescripción. Para ello se realizó un estudio prospectivo durante sesenta días, seleccionándose a partir del sistema de distribución de medicamentos en dosis unitarias los pacientes que iniciaban tratamiento analgésico. De los tratamientos analgésicos se registraron el fármaco prescrito, dosis pautada, asociación analgésica, vía de administración e intervalo posológico utilizado. Se analizaron 3.600 prescripciones médicas de las que un 39.22 por ciento fueron tratamientos analgésicos. Los resultados más sobresalientes fueron la alta utilización de metamizol magnésico, la infradosificación de la mayoría de los analgésicos analizados, la gran prescripción de tratamientos a demanda, así como un importante porcentaje de combinaciones analgésicas incorrectas. Por todo ello parece necesario la implantación de protocolos analgésicos en el servicio a estudio (AU)
Assuntos
Feminino , Humanos , Analgésicos/uso terapêutico , Prescrições de Medicamentos/estatística & dados numéricos , Procedimentos Cirúrgicos em Ginecologia/métodos , Estudos ProspectivosRESUMO
Cell growth in yeast colonies is a complex process, the control of which is largely unknown. Here we present scanning electron micrographs of Saccharomyces cerevisiae colonies, showing changes in the pattern of cell organization and cell-cell interactions during colony development. In young colonies (=36 h), cell density is relatively low, and the cells seem to divide in a random orientation. However, as the colonies age, cell density increases and the cells seem to be oriented in a more orderly fashion. Unexpectedly, cells in starved colonies form connecting fibrils. A single connecting fibril 180 +/- 50 nm wide is observed between any two neighboring cells, and the fibrils appear to form a global network. The results suggest a novel type of communication between cells within a colony that may contribute to the ability of the community to cope with starvation.
Assuntos
Saccharomyces cerevisiae/ultraestrutura , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/fisiologiaRESUMO
Rpb4 and Rpb7 are two yeast RNA polymerase II (Pol II) subunits whose mechanistic roles have recently started to be deciphered. Although previous data suggest that Rpb7 can stably interact with Pol II only as a heterodimer with Rpb4, RPB7 is essential for viability, whereas RPB4 is essential only during some stress conditions. To resolve this discrepancy and to gain a better understanding of the mode of action of Rpb4, we took advantage of the inability of cells lacking RPB4 (rpb4Delta, containing Pol IIDelta4) to grow above 30 degrees C and screened for genes whose overexpression could suppress this defect. We thus discovered that overexpression of RPB7 could suppress the inability of rpb4Delta cells to grow at 34 degrees C (a relatively mild temperature stress) but not at higher temperatures. Overexpression of RPB7 could also partially suppress the cold sensitivity of rpb4Delta strains and fully suppress their inability to survive a long starvation period (stationary phase). Notably, however, overexpression of RPB4 could not override the requirement for RPB7. Consistent with the growth phenotype, overexpression of RPB7 could suppress the transcriptional defect characteristic of rpb4Delta cells during the mild, but not during a more severe, heat shock. We also demonstrated, through two reciprocal coimmunoprecipitation experiments, a stable interaction of the overproduced Rpb7 with Pol IIDelta4. Nevertheless, fewer Rpb7 molecules interacted with Pol IIDelta4 than with wild-type Pol II. Thus, a major role of Rpb4 is to augment the interaction of Rpb7 with Pol II. We suggest that Pol IIDelta4 contains a small amount of Rpb7 that is sufficient to support transcription only under nonstress conditions. When RPB7 is overexpressed, more Rpb7 assembles with Pol IIDelta4, enough to permit appropriate transcription also under some stress conditions.
Assuntos
RNA Polimerase II/metabolismo , Transcrição Gênica , Dimerização , Dosagem de Genes , Resposta ao Choque Térmico/fisiologia , Ligação Proteica , Conformação Proteica , RNA Polimerase II/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae , Supressão GenéticaRESUMO
Two regulatory mutations of Myxococcus xanthus, which cause an increase in the transcription of genes required for antibiotic TA synthesis, were mapped by transduction and their effect on transcription of four TA genes examined. The two regulatory mutations were closely linked and located within the 40-kb TA gene cluster on the M. xanthus chromosome. Recombinants were constructed which contained one of the regulatory mutations and promoter probes in the four different TA genes. Both regulatory mutations enhanced transcription of three of the four TA genes. However, construction of a strain containing the over-expression regulatory mutation in a wild-type background produced less antibiotic than the parental strain.
Assuntos
Antibacterianos/biossíntese , Regulação Bacteriana da Expressão Gênica , Myxococcus xanthus/metabolismo , Macrolídeos , Mutação , Transcrição GênicaRESUMO
The calcium-channel blockers are an ever-enlarging, heterogeneous group of drugs with widely variable effects on myocardium, sinoatrial and atrioventricular nodal function and conduction, peripheral blood vessels, and coronary circulation. Since the development and characterization of calcium-channel antagonists in the 1960s, these agents have become increasingly important in the treatment of many cardiovascular diseases. Nine calcium-channel blockers-nifedipine, nicardipine, amlodipine, felodipine, isradipine, nimodipine, diltiazem, verapamil, and bepridil-are all approved for use in the United States. Each major category has its own unique physiologic features. These drugs are extremely useful in the management of cardiac arrhythmias (particularly supraventricular arrhythmias) and/or ischemia. As future generations of calcium-channel blockers are developed with greater vasoselectivity, less negative inotropic effects, and reduced tendency to activate the renin-angiotensin system, their indications for use will continue to grow.
Assuntos
Antiarrítmicos/uso terapêutico , Arritmias Cardíacas/tratamento farmacológico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Isquemia Miocárdica/tratamento farmacológico , Angioplastia Coronária com Balão , Antiarrítmicos/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/fisiologia , Cocaína/efeitos adversos , Transplante de Coração , Humanos , Traumatismo por Reperfusão Miocárdica/prevenção & controleRESUMO
In Israel, senior citizens spend more time in hospitals than do members of any other age group. Chronic, age-related illnesses make the senior population especially dependent on the hospital system. Hospitalization, however, has its own risks-frequent and/or prolonged hospital stay can increase susceptibility to infections and complications, and can lead to impairment of mobility and of overall functioning. In this study, we'll be taking a look at the use of patient restraints in geriatric institutions. We'll look at the factors that induce attending staff to restrain elderly patients, the kinds of restraints used, and the feeling of the staff on this controversial issue. We'll also present the results of interviews with nursing services administrators in several geriatric institutions on the subject of restraining policies and procedures. Our findings indicate that procedures and policies regarding restraint vary from one institution to another. In some cases there are no clear written procedures, and patients are restrained without the written and signed order of a physician. We also found that attending staff are not sufficiently knowledgeable about the legal issues involved in patient restraint.
Assuntos
Instituição de Longa Permanência para Idosos , Política Organizacional , Restrição Física , Idoso , Atitude do Pessoal de Saúde , Coleta de Dados , Ética Médica , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Israel , Restrição Física/legislação & jurisprudência , Inquéritos e QuestionáriosRESUMO
PURPOSE: A variety of preoperative provocative tests have been used to define the risk of cardiac morbidity and mortality after peripheral vascular procedures, including dipyridamole myocardial scintigraphy and dobutamine stress echocardiography. Although highly sensitive, these tests are time-consuming and associated with significant expense. We investigated outpatient echocardiography as a less resource-intensive means of assessing cardiac risk with operation. METHODS: Over a 2-year period 250 consecutive patients underwent outpatient transthoracic echocardiography before elective peripheral vascular operation was performed. The accuracy of the Goldman, Detsky, and the American Society of Anesthesiologists' Physical Status Classification clinical indexes of cardiac risk were assessed with regard to the development of cardiac complications such as unstable angina, myocardial infarction, life-threatening ventricular arrhythmias, severe congestive heart failure, and cardiogenic shock. The accuracy of echocardiographically determined left ventricular ejection fraction was determined at threshold values between 20% and 60%. RESULTS: Perioperative cardiac events developed in 23 (9.2%) of the patients, and nine (3.6%) of the patients died as a result of these complications. Clinical indexes lacked sensitivity in the preoperative prediction of cardiac complications. Receiver operating curve analysis defined a left ventricular ejection fraction of less than 50% as an appropriate threshold for defining patients at high risk, with a sensitivity of 78% and a specificity of 81% in the identification of patients who had cardiac morbidity. The positive predictive value was 27%, and the negative predictive value was 97%. The economic impact of outpatient echocardiography was well below that of dipyridamole myocardial scintigraphy or dobutamine stress echocardiography. CONCLUSIONS: Outpatient echocardiography appears to offer a cost-efficient compromise between clinical criteria alone and provocative cardiac testing such as dipyridamole myocardial scintigraphy and dobutamine stress echocardiography in the preoperative screening of patients undergoing peripheral vascular surgical procedures.
Assuntos
Ecocardiografia , Cardiopatias/diagnóstico , Cuidados Pré-Operatórios , Procedimentos Cirúrgicos Vasculares/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial , Feminino , Cardiopatias/etiologia , Cardiopatias/mortalidade , Cardiopatias/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/prevenção & controle , Valor Preditivo dos Testes , Curva ROC , Fatores de Risco , Sensibilidade e Especificidade , Volume SistólicoRESUMO
We present a rare case of recurrent sustained maternal ventricular tachycardia associated with hypomagnesemia. The frequency of this arrhythmia was markedly reduced with magnesium sulfate therapy. Both maternal and fetal outcomes were good. To the best of our knowledge this is the first description of maternal ventricular tachycardia that was associated with hypomagnesemia and did not require treatment with conventional antiarrhythmic medications. We discuss the possible underlying pathophysiologic causes of this condition.
Assuntos
Magnésio/sangue , Complicações Cardiovasculares na Gravidez/etiologia , Taquicardia Ventricular/etiologia , Adulto , Feminino , Humanos , Sulfato de Magnésio/uso terapêutico , Gravidez , Complicações Cardiovasculares na Gravidez/sangue , Complicações Cardiovasculares na Gravidez/tratamento farmacológico , Taquicardia Ventricular/sangue , Taquicardia Ventricular/tratamento farmacológicoRESUMO
Transposition of TnV and Tn5lac into Myxococcus xanthus yielded 8,381 kanamycin-resistant mutants that were tested for antibiotic TA production. Twenty-four of the mutants were nonproducers of TA (less than 0.4 ng/ml), and 3 produced a higher level (2.5 micrograms/ml) than the parent strain (1.5 micrograms/ml). For most of the strains, there was 100% cotransduction between kanamycin resistance and the altered TA phenotype. Southern blot analysis of restriction digests of the mutant DNA indicated that the transposons were inserted at different sites on the M. xanthus chromosome. The TA genes were mapped by cotransduction between pairs of mutants following replacement of the initial insert of one of the pair with the tetracycline resistance transposon Tn5-132. Nine of the 13 nonproducers tested were linked over a 36-kb stretch of the chromosome. There was no linkage between one of the overproducers and any of the nonproducers tested.
Assuntos
Antibacterianos/biossíntese , Myxococcus/genética , Mapeamento Cromossômico , Elementos de DNA Transponíveis/genética , Resistência a Canamicina , Macrolídeos , Mutagênese , Myxococcus/metabolismo , FenótipoRESUMO
The beta-galactosidase activities arising from Tn5lac insertions in several genes required for antibiotic TA production were measured under different growth conditions. In all of the non-TA-producing mutants, the beta-galactosidase specific activity was higher when the cells were grown in nutrient-limited 0.5CTS medium (0.5% Casitone plus alanine, serine, and glucose) than in rich 2CT medium (2% Casitone). One of the mutants, 420, had low beta-galactosidase specific activity in both media. The other seven mutants containing inserts in genes essential for TA production had specific activities of 139 to 367 U/mg of protein in 0.5CTS medium and 11 to 48 U/mg of protein in 2CT medium. The beta-galactosidase specific activities of two strains, 1030 and 420, increased during exponential growth in 0.5CTS medium. The beta-galactosidase specific activities of both strains increased greatly when the cells were grown in the presence of magnesium phosphate, which traps ammonium ions. The Tn5lac insertions in 1030 and 420 were used to screen for mutants with increased levels of transcription. An N-methyl-N'-nitro-N-nitrosoguanidine-induced mutation in 1030 that mapped 17 kb from the omega 1010 insert increased the specific activity of beta-galactosidase 21 times in 2CT medium. The regulatory mutation appears to release the repression caused by 2CT medium. A UV-induced mutation in 420 increased the beta-galactosidase specific activity 1.4 to 2.4 times. Medium conditions that affect the transcription of TA genes are discussed in terms of enhanced antibiotic TA production.
Assuntos
Antibacterianos/biossíntese , Galactosidases/metabolismo , Myxococcus/enzimologia , Regulação Bacteriana da Expressão Gênica , Macrolídeos , Mutagênese , Myxococcus/genética , Myxococcus/metabolismo , Transcrição GênicaRESUMO
The adhesive antibiotic TA was applied to the dento-gingival junction of 8 human volunteers, suffering from moderate to severe gingivitis. 2 diametrically opposed quadrants of the mouth received 4 applications of 0.1 mg TA, while the other 2 quadrants were treated with a placebo and served as controls. The plaque index, gingival index and bleeding index were scored periodically for 2 weeks and in 4 patients for up to 30 days. The TA-treated quadrants showed a rapid decrease in all 3 indices following 2 treatments. A further improvement was observed with the 3rd and 4th treatments. 30 days after the onset of the experiment and 23 days after the last application, the indices were still considerably lower than the initial values.
Assuntos
Antibacterianos/uso terapêutico , Placa Dentária/prevenção & controle , Quimioterapia Combinada/uso terapêutico , Gengivite/prevenção & controle , Adulto , Índice de Placa Dentária , Método Duplo-Cego , Hemorragia Gengival/diagnóstico , Humanos , Macrolídeos , Índice Periodontal , PlacebosRESUMO
Autocide AMV of Myxococcus xanthus was purified and identified as phosphatidylethanolamine. Alkaline hydrolysis of AMV yielded a high proportion of mono- and diunsaturated fatty acids. The bactericidal activity of AMV on M. xanthus depended upon the density of target cells: the greater the cell density, the greater the killing by AMV. For example, at 2 U of AMV per ml, 0, 50, and 99% killing was measured with 2 X 10(4), 2 X 10(5), and 2 X 10(7) target cells per ml, respectively. The cell-density-dependent activity of AMV was also observed on solid medium. Studies with model lipid compounds suggest that the inhibitory activity of AMV is due to the fatty acid moiety, released from phosphatidylethanolamine by the concerted (enzymatic) activity of many cells. Mutants of M. xanthus selected for resistance to AMI (a mixture of fatty acids) were also resistant to AMV. The possible role of AMV in developmental lysis is discussed.
Assuntos
Myxococcales/crescimento & desenvolvimento , Fosfatidiletanolaminas/isolamento & purificação , Cromatografia em Camada Fina , Meios de Cultura , Resistência Microbiana a Medicamentos , Lipídeos/farmacologia , Mutação , Myxococcales/efeitos dos fármacos , Fosfatidiletanolaminas/fisiologia , Relação Estrutura-AtividadeRESUMO
Autocide AMI of Myxococcus xanthus was purified and shown to be a mixture of fatty acids: 46.4% saturated, 49.3% monounsaturated, and 4.3% diunsaturated. The specific autocidal activities (units per milligram) were as follows: purified AMI, 1,000; saturated fraction, 100; monounsaturated fraction, 800; diunsaturated fraction, 2,200. Model fatty acids mimicked to some extent the activity of AMI, although none of the fatty acids tested were as active as purified AMI. Spontaneous and induced mutants of M. xanthus were selected for resistance to AMI and to fatty acids. The AMI-resistant mutants were also resistant to the model fatty acids, whereas resistance to fatty acids was specific to the compound used for mutant selection. All AMI- and fatty acid-resistant mutants examined were found to be blocked in fruiting body formation. Some of these mutants were able to form normal fruiting bodies when mixed with the extracellular fluid of the parental strain. The data suggest that AMI plays a role in developmental lysis of M. xanthus.