RESUMO
Cassava brown streak disease (CBSD), caused by cassava brown streak ipomoviruses (CBSIs), has become the most debilitating biotic stress to cassava production in East and Central Africa. Lack of CBSD-resistant varieties has necessitated the search for alternative control measures. Most smallholder farmers reuse stems from previous crops for planting in the new season. Recycling planting material in this way can lead to "degeneration" owing to the compounding effects of disease. In this study, degeneration was defined as the increase in CBSD incidence and reduction in marketable root yield over time. An experiment was established to study the rates of degeneration in selected cassava varieties Chereko, KBH2002_135, Kipusa, Kizimbani, and Mkuranga1 and cultivars Kiroba and Kikombe under high-CBSD inoculum conditions in Bagamoyo, Tanzania from 2013 to 2017. The experiment was replicated across two seasons: the first planted during the long rains (Masika) between March and June and the second planted during the short rains (Vuli) between October and December. Mean abundance of the whitefly vector (Bemisia tabaci) was much greater during the Vuli season (>19 insects per plant) than the Masika season (<2 insects per plant). CBSD shoot symptoms occurred naturally and were observed only on Kikombe, Kiroba, and Kipusa. New materials had overall lower CBSD shoot incidences (1.5%) compared with recycled materials (6.9%) in Masika, although no significant differences were obvious in Vuli. However, Masika (8.7%) had an overall lower CBSD shoot incidence than Vuli (16.5%) in the varieties that had shoot symptoms. CBSD root incidences were higher in Vuli (10.3%) than Masika (4.4%), and root yields in Masika (29.4 t/ha) were significantly greater than those in Vuli (22.5 t/ha). The highest percentage of roots rendered unusable owing to CBSD was observed in Vuli. There was significantly higher unusable root incidence in recycled materials (3.7%) than in new materials (1.4%) in Masika but not in Vuli. Overall root yield was similar between recycled and new materials in either season. Significant reductions in root yield over the course of the experiment were observed both in Masika and Vuli, whereas changes in marketable yield were significant only in Masika. Differences in the response of varieties to degeneration led to the identification of four degeneration patterns, namely "strong," "moderate," "mild," and "delayed" degeneration. The strongest effects of degeneration were most obvious in the susceptible cultivar (Kikombe), which also had the lowest marketable yield in either season. Seasonal differences were a key driver of degeneration, because its effects were much greater in Vuli than Masika. To the best of our knowledge, this work reports the first study of degeneration caused by cassava viruses.[Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
Assuntos
Manihot , Potyviridae , África Central , Animais , Manihot/microbiologia , Manihot/virologia , Doenças das Plantas/virologia , Potyviridae/fisiologia , TanzâniaRESUMO
Salmon farming is the main economic activity in the fjords area of Southern Chile. This activity requires the use of antibiotics, such as oxytetracycline, for the control and prevention of diseases, which have a negative impact on the environment. We analyzed the abilities of endemic marine fungi to biodegrade oxytetracycline, an antibiotic used extensively in fish farming. We isolated marine fungi strains from sediment samples obtained from an area of fish farming activity. The five isolated strains showed an activity on oxytetracycline and were identified as Trichoderma harzianum, Trichoderma deliquescens, Penicillium crustosum, Rhodotorula mucilaginosa, and Talaromyces atroroseus by a scanning electron microscopy and characterized by molecular techniques. Results showed significant degradation in the concentration of oxytetracycline at the first 2 days of treatment for all strains analyzed. At 21 days of treatment, the concentration of oxytetracycline was decreased 92 % by T. harzianum, 85 % by T. deliquescens, 83 % by P. crustosum, 73 % by R. mucilaginosa, and 72 % by T. atroroseus, all of which were significantly higher than the controls. Given these results, we propose that fungal strains isolated from marine sediments may be useful tools for biodegradation of antibiotics, such as oxytetracycline, in the salmon industry.
Assuntos
Antibacterianos/análise , Monitoramento Ambiental/métodos , Fungos/crescimento & desenvolvimento , Sedimentos Geológicos/microbiologia , Oxitetraciclina/análise , Poluentes Químicos da Água/análise , Animais , Aquicultura , Biodegradação Ambiental , Chile , Estuários , Fungos/isolamento & purificação , Salmão/crescimento & desenvolvimento , Microbiologia da ÁguaRESUMO
Cassava is an important food crop in western Kenya, yet its production is challenged by pests and diseases that require routine monitoring to guide development and deployment of control strategies. Field surveys were conducted in 2022 and 2023 to determine the prevalence, incidence and severity of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), whitefly numbers and incidence of cassava green mite (CGM) in six counties of western Kenya. Details of the encountered cassava varieties were carefully recorded to determine the adoption of improved varieties. A total of 29 varieties were recorded, out of which 13 were improved, although the improved varieties were predominant in 60% of fields and the most widely grown variety was MM96/4271. The CMD incidence was higher in 2022 (26.4%) compared to 2023 (10.1%), although the proportion of CMD attributable to whitefly infection was greater (50.6%) in 2023 than in 2022 (18.0%). The CBSD incidence in 2022 was 6.4%, while in 2023 it was 4.1%. The CMD incidence was significantly lower (5.9%) for the improved varieties than it was for the local varieties (35.9%), although the CBSD incidence did not differ significantly between the improved (2.3%) and local varieties (9.7%). Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) were both detected. Most infections were single CBSV infections (82.9%), followed by single UCBSV (34.3%) and coinfection with both viruses (16.7%). Whiteflies were more abundant in 2023, in which 28% of the fields had super-abundant populations of >100/plant, compared to 5% in 2022. KASP SNP genotyping designated 92.8% of the specimens as SSA-ECA for 2022, while it was 94.4% for 2023. The cassava green mite incidence was 65.4% in 2022 compared to 79.9% in 2023. This study demonstrates that cassava viruses, whiteflies and cassava green mites continue to be important constraints to cassava production in western Kenya, although the widespread cultivation of improved varieties is reducing the impact of cassava viruses. The more widespread application of high-quality seed delivery mechanisms could further enhance the management of these pests/diseases, coupled with wider application of IPM measures for whiteflies and mites.
Assuntos
Manihot , Doenças das Plantas , Manihot/virologia , Manihot/parasitologia , Quênia/epidemiologia , Doenças das Plantas/virologia , Doenças das Plantas/parasitologia , Animais , Hemípteros/virologia , Potyviridae/genética , Potyviridae/isolamento & purificação , Incidência , Psychodidae/virologia , Psychodidae/parasitologiaRESUMO
The present study characterizes Bemisia tabaci and Bemisia afer from cassava in eastern Democratic Republic of Congo (DRC). The Mitochondrial COI sequencing revealed the occurrence of six cassava B. tabaci mitotypes, which were designated into four haplogroups (SSA-ECA, SSA-CA, SSA2, and SSA-ESA) using KASP SNP genotyping. SSA-ECA (72%) was the most prevalent and occurred in the northern part of the surveyed area, in the Ituri and Nord/Sud-Kivu provinces, whilst SSA-CA (21%) was present in the south, primarily in Haut-Katanga. SSA-ECA was predominant in the areas of north-eastern DRC most severely affected by cassava brown streak disease and was also reported in the new outbreak area in Pweto territory, Haut-Katanga, in the south. Bemisia afer comprised two major clusters with 85.5% of samples in cluster one, while the rest were in cluster two, which has no reference sequence in GenBank. This study provides important information on the genetic diversity of B. tabaci and B. afer in eastern DRC. This knowledge will be used as a basis for further studies to understand and to identify the role of whitefly haplogroups, their population densities and consequences for virus epidemics and spread as well as leading to improved vector and virus management strategies.
RESUMO
Bone morphogenetic proteins (BMPs) stimulate bone formation and thus constitute important protein therapeutics. Here, a novel procedure is presented which allows fast and efficient production of biologically active BMP-2 via a TWO-STEP procedure: the conditions are designed such that the first step favors formation of monomeric species with the correct intramolecular disulfide bridges, the conditions of the second folding reaction stimulate the formation of the intermolecular disulfide bridge. The short processing times and increased yields compared to previously published procedures allow low-cost production of this important protein drug.
Assuntos
Proteína Morfogenética Óssea 2/biossíntese , Fosfatase Alcalina/biossíntese , Proteína Morfogenética Óssea 2/química , Proteína Morfogenética Óssea 2/genética , Eletroforese em Gel de Poliacrilamida , Indução Enzimática , Escherichia coli/genética , Humanos , Corpos de Inclusão/química , Corpos de Inclusão/metabolismo , Oxirredução , Dobramento de Proteína , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMO
Cassava brown steak disease (CBSD), caused by Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), is the most important biotic constraint to cassava production in East and Central Africa. Concerted efforts are required to prevent further spread into West Africa as well as to reduce losses in areas already affected. The study reported here was part of a five-country (Kenya, Malawi, Mozambique, Tanzania and Uganda) programme that aimed to identify superior cassava cultivars resistant to CBSD and to disseminate them widely in the region. Seventeen tissue-cultured and virus-tested cultivars were evaluated in Tanzania across nine sites with diverse CBSD inoculum conditions. Experiments were planted using an alpha-lattice design and assessments were made of surrounding inoculum pressure, CBSD foliar and root incidence and root yield at harvest. There were large differences in CBSD infection between sites, with greatest spread recorded from the north-western Lake (Victoria) zone. Differences were driven by Bemisia tabaci whitefly vector abundance and CBSD inoculum pressure. Both CBSV and UCBSV were almost equally represented in cassava fields surrounding experimental plots, although CBSV predominated in the north-west whilst UCBSV was more frequent in coastal and southern sites. However, the incidence of CBSV was much greater than that of UCBSV in initially virus-free experimental plots, suggesting that CBSV is more virulent. Cultivars could be categorised into three groups based on the degree of CBSD symptom expression in shoots and roots. The seven cultivars (F10_30R2, Eyope, Mkumba, Mkuranga1, Narocass1, Nase3 and Orera) in the most resistant category each had shoot and root incidences of less than 20%. Fresh root yield differed between sites and cultivars, but there was no genotype by environment interaction for this trait, probably attributable to the large fertility and soil moisture differences between sites. Susceptible cultivars and the local check performed well in the absence of CBSD pressure, highlighting the importance of exploiting quality and yield traits of local landraces in breeding programmes. Overall, our results emphasized the importance of applying a balanced strategy for CBSD management. This should use both improved and local germplasm resources to generate high yielding cultivars for specific end-user traits, and combine the deployment of improved cultivars with phytosanitary control measures including the use of healthy planting material and planting during periods of reduced CBSD infection.
Assuntos
Resistência à Doença/genética , Manihot/virologia , Doenças das Plantas/virologia , Potyviridae/genética , Genótipo , Filogenia , Doenças das Plantas/genética , RNA Viral/genética , Análise de Sequência de DNA , TanzâniaRESUMO
The use of correlated microscopic techniques, including the scanning electron microscopic modes of backscattered electron imaging and energy dispersive x-ray analysis, aid in defining the process of dispersion of silicon-containing material around silicone rubber (polydimethylsiloxane) prosthetic devices.
Assuntos
Mama/metabolismo , Dimetilpolisiloxanos , Próteses e Implantes/efeitos adversos , Silício/metabolismo , Silicones , Mama/cirurgia , Mama/ultraestrutura , Dimetilpolisiloxanos/metabolismo , Feminino , Humanos , Silicones/metabolismo , Vacúolos/metabolismo , CicatrizaçãoRESUMO
Two and a half years of data of ambient concentrations of elemental mercury (Hg(0)), reactive gaseous mercury (RGM), and particle-bound mercury (Hg(p)) were collected at measurement sites at Elizabeth, New Jersey and New Brunswick, New Jersey with Tekran sampling units. The data were processed, summarized, and analyzed from a variety of perspectives. Data quality control and quality assurance procedures are described. Wind direction and wind speed data for each of the sites were also collected. Significant temporal variations in concentrations of all three species were observed. Some significant directional variations were also seen. The sporadic nature of many of the temporal variations is consistent with and could reflect highly variable emissions patterns from anthropogenic mercury sources. Overall mean concentrations of all species were determined. These were, for Hg(0), Hg(p), and RGM respectively; 2.25 +/- 0.04 nanograms per cubic meter (ng/m(3)), 8.21 +/- 0.39 picograms per cubic meter (pg/m(3)), and 8.93 +/- 0.31 pg/m(3) (arithmetic means and 95% confidence intervals) at Elizabeth, and 2.15 +/- 0.02 ng/m(3), 10.73 +/- 0.45 pg/m(3), and 6.04 +/- 0.30 pg/m(3) at New Brunswick. Mean concentrations were determined for 16 different sectors representing wind directions. The impact of one known large source is suggested by these data. Reasons for some directional variations are not apparent and suggest a need for further investigation.
Assuntos
Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental , Mercúrio/análise , Mercúrio/química , Vento , New JerseyRESUMO
The whitefy Bemisia tabaci, a species complex consisting of many morphologically indistinguishable species divided into distinct clades, is one of the most globally important agricultural pests and plant virus vectors. Cassava-colonizing B. tabaci transmits viruses that cause cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Half of all cassava plants in Africa are affected by these viral diseases, resulting in annual production losses of more than US$ 1 billion. Here we report the draft genome of the cassava whitefly B. tabaci Sub-Saharan Africa - East and Central Africa (SSA-ECA), the super-abundant population that has been associated with the rapid spread of viruses causing the pandemics of CMD and CBSD. The SSA-ECA genome assembled from Illumina short reads has a total size of 513.7â¯Mb and a scaffold N50 length of 497â¯kb, and contains 15,084 predicted protein-coding genes. Phylogenetic analysis suggests that SSA-ECA diverged from MEAM1 around 5.26 million years ago. A comprehensive genetic analysis of cassava-colonizing B. tabaci in Africa was also conducted, in which a total of 243 whitefly specimens were collected from 18 countries representing all major cassava-growing regions in the continent and genotyped using NextRAD sequencing. Population genomic analyses confirmed the existence of six major populations linked by gene flow and inferred the distribution patterns of these populations across the African continent. The genome of SSA-ECA and the genetic findings provide valuable resources and guidance to facilitate whitefly research and the development of strategies to control cassava viral diseases spread by whiteflies.
Assuntos
Distribuição Animal , Variação Genética , Genoma de Inseto , Hemípteros/genética , Herbivoria/genética , África , Animais , Comportamento Alimentar , Hemípteros/fisiologia , Manihot/crescimento & desenvolvimento , FilogeniaRESUMO
Marrow grafts were carried out between 16 canine sibling donor-recipient pairs. The pairs were matched by serological histocompatibility testing and were nonreactive in a one-way mixed leukocyte culture. Recipients were prepared for transplantation by 1500-1580 R of total body irradiation. Donor marrow was infused within 4 hr of irradiation. Recipients were not given immunosuppressive drug therapy after grafting. All 16 recipients showed evidence of prompt and sustained allogeneic marrow engraftment. Six died between 30 and 128 days after grafting with graft-versus-host disease, and three died between days 72 and 230 with pneumonia but no evidence of graft-versus-host disease with the exception of lymphoid atrophy. Seven recipients survived without graft-versus-host disease and are in excellent health between 200 and 684 after grafting. In summary, fatal graft-versus-host disease was observed in a number of canine recipients despite matching with their sibling donor by serological histocompatibility testing and by mixed leukocyte culture in a manner similar to that employed to define human HL-A matched sibling pairs. The graft-versus-host disease in these matched siblings developed more slowly than that observed in mismatched dogs, but the ultimate death of approximately half of the matched recipients emphasizes the need for posttransplantation immunosuppression even in this "compatible" situation.
Assuntos
Transplante de Medula Óssea , Cães/imunologia , Histocompatibilidade , Leucócitos/imunologia , Animais , Técnicas de Cultura , Doença Enxerto-Hospedeiro/etiologia , Terapia de Imunossupressão , Contagem de Leucócitos , Leucócitos/metabolismo , Metotrexato/uso terapêutico , Modelos Biológicos , Sorotipagem , Transplante HomólogoRESUMO
This report describes a search for tumor-specific transplantation antigens in man by testing four sets of identical siblings using the mixed leukocyte transformation reaction. In each case, one member of the set had acute leukemia in relapse. In no instance did the leukemic cells of the patient stimulate the cells of the normal twin, nor did cells from the normal twin stimulate cells from the leukemic patient. Possible explanations for the failure to detect a leukemia-associated antigen in these studies are discussed.
Assuntos
Doenças em Gêmeos/imunologia , Leucemia Linfoide/imunologia , Leucemia Mieloide Aguda/imunologia , Leucócitos/imunologia , Linfócitos/imunologia , Imunologia de Transplantes , Antígenos , Técnicas de Cultura , Humanos , Leucócitos/metabolismo , Ativação Linfocitária , Timidina/metabolismo , TrítioRESUMO
Some human chronic dermal wounds treated with recombinant platelet-derived growth factor-BB (rPDGF-BB) show increased healing coupled with fibroblast activation and granulation tissue formation. To determine whether endogenous PDGF is associated with healing and nonhealing dermal ulcer phenotypes, we developed monoclonal antibodies capable of recognizing the three isoforms of PDGF, AA, AB, and BB dimers, and capable of discriminating between two alternatively spliced A chain transcripts. We detected little PDGF isoform expression in normal skin and in nonhealing dermal ulcers. In contrast, in surgically created acute wounds and chronic ulcers treated with rPDGF-BB, markedly upregulated levels of PDGF-AA (long form) were found. In both types of wounds, increased PDGF-AA was detected primarily in capillaries and fibroblasts, although in rPDGF-BB-treated chronic wounds, widespread expression of PDGF-AA was somewhat delayed. With continued treatment, the long form of PDGF-AA, which can preferentially bind extracellular matrix, was expressed only in capillaries, while fibroblasts began synthesizing the short form of PDGF-AA. Within capillaries, all endothelial cells and varying numbers of pericytes and smooth muscle cells contained PDGF-AA. In all wounds, macrophages and keratinocytes were not a major contributor. While PDGF-BB and PDGF-AB were present in a minority of healing wounds, they were usually present at lower levels than PDGF-AA. PDGF-beta receptors, which bind only PDGF-BB and not other isoforms, were found in normal skin and granulation tissue, providing a molecular basis for treating human chronic wounds with exogenous rPDGF-BB.
Assuntos
Fator de Crescimento Derivado de Plaquetas/biossíntese , Fator de Crescimento Derivado de Plaquetas/uso terapêutico , Úlcera por Pressão/tratamento farmacológico , Úlcera por Pressão/fisiopatologia , Cicatrização , Adulto , Animais , Anticorpos Monoclonais , Arteríolas/patologia , Arteríolas/ultraestrutura , Becaplermina , Células CHO , Cricetinae , Endotélio Vascular/patologia , Endotélio Vascular/ultraestrutura , Fibroblastos/patologia , Fibroblastos/ultraestrutura , Humanos , Microscopia Imunoeletrônica , Fator de Crescimento Derivado de Plaquetas/análise , Úlcera por Pressão/patologia , Proteínas Proto-Oncogênicas c-sis , Proteínas Recombinantes/análise , Proteínas Recombinantes/uso terapêutico , Traumatismos da Medula Espinal/fisiopatologia , Transfecção , Cicatrização/efeitos dos fármacosRESUMO
Fusion proteins of monomeric alpha-glucosidase from Saccharomyces cerevisiae containing N- or C-terminal hexa-arginie peptides were expressed in the cytosol of Escherichia coli in soluble form. The polycationic peptide moieties allow noncovalent binding of the denatured fusion proteins to a polyanionic solid support. Upon removal of the denaturant, refolding of the matrix-bound protein can proceed without perturbation by aggregation. However, nonspecific interactions of the denatured polypeptide, or of folding intermediates, with the matrix cause a drastic decrease in renaturation under suboptimal folding conditions. At low salt concentrations, ionic interactions of the refolding polypeptide with the matrix result in lower yields of renaturation. At higher salt concentrations, renaturation is prevented by hydrophobic interactions with the matrix. Apart from ionic strength, renaturation of the denatured matrix-bound fusion protein must be optimized with respect to pH, temperature, cosolvents, and matrix material used. Under optimum conditions, immobilized alpha-glucosidase can be renatured with a high yield at protein concentrations up to 5 mg/ml, whereas folding of the wild-type enzyme in solution is feasible only at an extremely low protein concentration (15 micrograms/ml). Thus, folding of the immobilized alpha-glucosidase allows an extremely high yield of the renaturated model protein. The technology should be applicable to other proteins that tend to aggregate during refolding.
Assuntos
Proteínas Recombinantes de Fusão/química , Biotecnologia , Enzimas Imobilizadas , Escherichia coli/genética , Concentração Osmolar , Conformação Proteica , Desnaturação Proteica , Dobramento de Proteína , Proteínas Recombinantes de Fusão/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Cloreto de Sódio , Temperatura , alfa-Glucosidases/química , alfa-Glucosidases/genéticaRESUMO
We have designed a new method for enzyme immobilization using a fusion protein of yeast alpha-glucosidase containing at its C-terminus a polycationic hexa-arginine fusion peptide. This fusion protein can be directly adsorbed from crude cell extracts on polyanionic matrices in a specific, oriented fashion. Upon noncovalent immobilization by polyionic interactions, the stability of the fusion protein is not affected by pH-, urea-, or thermal-denaturation. Furthermore, the enzymatic properties (specific activity at increasing enzyme concentration, Michaelis constant, or activation energy of the enzymatic reaction) are not influenced by this noncovalent coupling. The operational stability of the coupled enzyme under conditions of continuous substrate conversion is, however, increased significantly compared to the soluble form. Fusion proteins containing polyionic peptide sequences are proposed as versatile tools for the production of immobilized enzyme catalysts.
Assuntos
Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Reatores Biológicos , Biotecnologia , Catálise , Desenho de Fármacos , Estabilidade Enzimática , Cinética , Saccharomyces cerevisiae/enzimologia , Solubilidade , alfa-Glucosidases/química , alfa-Glucosidases/metabolismoRESUMO
Gene delivery has shown potential in a variety of applications, including basic research, therapies for inborn genetic defects, cancer, AIDS, tissue engineering, and vaccination. Most available systems have serious drawbacks, such as safety hazards, inefficiency under in vivo-like conditions, and expensive production. When using naked DNA, for instance, a large amount of ultrapure DNA has to be applied as a result of degradation by nucleases. Similarly, the use of eukaryotic histones, synthetic peptides, or peptide nucleic acids may be limited by high production costs. We have demonstrated a biotechnologically feasible and economical approach for gene delivery using the histone-like protein from the hyperthermostable eubacterium Thermotoga maritima, TmHU as an efficient gene transfer reagent. HU can be easily isolated from recombinant Escherichia coli, is extraordinarily stable, and protects dsDNA from thermal denaturation. This study demonstrates its use as an inexpensive tool for gene delivery.
Assuntos
Proteínas de Bactérias/química , Proteínas de Ligação a DNA/genética , Técnicas de Transferência de Genes , Transfecção/métodos , Células 3T3 , Animais , Linhagem Celular , Proteínas de Ligação a DNA/química , Relação Dose-Resposta a Droga , Células Eucarióticas , Feminino , Galactosídeos/metabolismo , Histonas/química , Humanos , Indóis/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/metabolismo , Temperatura , Thermotoga maritima/química , Fatores de TempoRESUMO
Contamination and infection with extensive drug resistant (XDR) bacteria are increasing in urology with the exception of methicillin resistant Staphylococcus aureus (MRSA) (stabilization). They often lead to logistic and therapeutical problems. Only 30-50% of XDR cases are of exogenous origin. To slow this trend, screening, hygiene programs, isolation, decontamination, targeted therapy of symptomatic infections, education programs, and success controls should be applied. Furthermore, all regulatory and legal instructions should be followed. Local hygiene networks help to find apt measures for XDR control. It is important to balance hygiene measures against hygiene hysteria. To prepare urological instruments, a local instrument preparation plan that takes into consideration all legal instructions should be followed. The efforts in health system general prophylactic measures should be supported. Only with consistent implementation in all areas of daily life (health care, local environment, animal husbandry, and soil contaminated within the framework of animal husbandry) can a substantial reduction of XDR bacteria be achieved in the long term.
Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/prevenção & controle , Infecções Relacionadas a Cateter/prevenção & controle , Descontaminação/métodos , Higiene , Staphylococcus aureus Resistente à Meticilina , Infecções Urinárias/prevenção & controle , Infecções Bacterianas/etiologia , Infecções Relacionadas a Cateter/etiologia , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/etiologia , Infecção Hospitalar/prevenção & controle , Medicina Baseada em Evidências , Humanos , Recidiva , Prevenção Secundária/métodos , Infecções Urinárias/etiologiaRESUMO
Cassava brown streak disease (CBSD) is the most important virus disease of cassava and a major food security threat in Africa. Yearly economic losses of up to $100 million USD have been attributed to CBSD. The lack of information on plant-virus interactions has restricted progress in breeding for CBSD resistance. Virus quantification is becoming a major tool for the quick and reliable assessment of plant host resistance. Therefore, a protocol for specific absolute quantification of Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) was developed. CBSV and UCBSV coat protein (CP) specific standard templates: CBSV (pFer2, 826bp) and UCBSV (pUF1-R1-1, 732) respectively were generated and maintained in a TA cloning vector. These were used to construct standard curves using a TaqMan qPCR assay. Standard curves with acceptable amplification efficiencies (90-105%) and coefficients of determination (R2) greater than 0.99 were obtained. Infected cassava plants were sampled from a screenhouse and the field and used to validate this assay. Results obtained by testing several screenhouse and field samples revealed consistent absolute quantification assays for different CBSV and UCBSV isolates. This study presents the first protocol for absolute quantification of CBSVs and is expected to accelerate screening for CBSD resistance and hence breeding for CBSD resistance. The use of the method presented here should improve the clarity of virus quantification data as the results obtained are not influenced by varietal, host, seasonal or environmental conditions. Screening efficiency will also be greatly improved as there is no need for the use of reference genes consequently allowing for a larger number of samples to be analyzed. This will increase experimental precision in a timely and cost effective manner.
Assuntos
Potyviridae/isolamento & purificação , RNA Mensageiro/análise , RNA Viral/análise , Carga Viral/métodos , África , Vetores Genéticos , Manihot/virologia , Potyviridae/genética , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real/métodosRESUMO
BACKGROUND: The explosive growth in the rate of X-ray determination of protein structures is fuelled largely by the expectation that structural information will be useful for pharmacological and biotechnological applications. For example, there have been intensive efforts to develop orally administrable antithrombotic drugs using information about the crystal structures of blood coagulation factors, including thrombin. Most of the low molecular weight thrombin inhibitors studied so far are based on arginine and benzamidine. We sought to expand the database of information on thrombin-inhibitor binding by studying new classes of inhibitors. RESULTS: We report the structures of three new inhibitors complexed with thrombin, two based on 4-aminopyridine and one based on naphthamidine. We observe several geometry changes in the protein main chain and side chains which accompany inhibitor binding. The two inhibitors based on 4-aminopyridine bind in notably different ways: one forms a water-mediated hydrogen bond to the active site Ser195, the other induces a rotation of the Ser214-Trp215 peptide plane that is unprecedented in thrombin structures. These binding modes also differ in their 'weak' interactions, including CH-O hydrogen bonds and interactions between water molecules and aromatic pi-clouds. Induced-fit structural changes were also seen in the structure of the naphthamidine inhibitor complex. CONCLUSIONS: Protein flexibility and variable water structures are essential elements in protein-ligand interactions. Ligand design strategies that fail to take this into account may overlook or underestimate the potential of lead structures. Further, the significance of 'weak' interactions must be considered both in crystallographic refinement and in analysis of binding mechanisms.
Assuntos
Antitrombinas/química , Inibidores de Serina Proteinase/química , Trombina/química , 4-Aminopiridina/análogos & derivados , 4-Aminopiridina/química , Animais , Sítios de Ligação , Bovinos , Simulação por Computador , Cristalografia por Raios X , Desenho de Fármacos , Humanos , Ligantes , Modelos Moleculares , Dados de Sequência Molecular , Naftalenos/química , Relação Estrutura-AtividadeRESUMO
Skin necrosis was produced in 24 male Fischer 344 rats by intradermal injection of 0.5 ml of doxorubicin (Adriamycin) at a concentration of 2 mg/ml. The resulting wounds healed slowly over 6 to 7 weeks with the reduced contraction rate paralleling the prolonged morbidity of doxorubicin ulcers in humans. Electron microscopy showed bizarre rough endoplasmic reticulum, double-walled vacuoles, and swollen mitochondria from 1 through 12 weeks after injury. Myofibroblasts with 60- to 80-A microfilaments with electron-dense bodies, intercellular connections, and prominent microtubules were seen from 4 through 12 weeks after injury. Although the appearance of myofibroblasts was delayed, their structure was normal. The delayed contraction of doxorubicin-induced skin ulcers thus appears due to persistent nonspecific cellular damage at the nuclear level rather than to specific derangement of myofibroblast function.
Assuntos
Doxorrubicina/efeitos adversos , Úlcera Cutânea/induzido quimicamente , Animais , Retículo Endoplasmático/ultraestrutura , Masculino , Dilatação Mitocondrial , Miofibrilas/ultraestrutura , Necrose/patologia , Ratos , Ratos Endogâmicos F344 , Úlcera Cutânea/patologia , Fatores de Tempo , CicatrizaçãoRESUMO
While extravasation from intravenous (IV) lines is common and usually benign, leakage of certain drugs can cause severe skin ulceration. These ulcerogenic drugs can be conveniently divided into two categories, depending on whether they bind to DNA. Chemotherapeutic agents such as doxorubicin, which bind to DNA, are especially prone to cause severe extravasation skin ulcers. These ulcers are often chronic and progressive. Neither clinical nor experimental studies have shown an antidote to doxorubicin extravasation, which is best prevented by careful technique. If extravasation is suspected, the infusion should be immediately stopped. In the event of extravasation, elevation and ice are the currently recommended treatment. While small ulcerations may on occasion heal, large ulcerations require surgical excision for relief of pain and salvage of underlying tissues.