Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
3 Biotech ; 14(3): 91, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38419684

RESUMO

Oil palm processing generates substantial waste materials rich in organic content, posing various environmental challenges. Anaerobic digestion (AD), particularly for palm oil mill effluent (POME), offers a sustainable solution, by converting waste into valuable biomethane for thermal energy or electricity generation. The synergistic activities of the AD microbiota directly affect the biomethane production, and the microbial community involved in biomethane production in POME anaerobic digestion has been reported. The composition of bacterial and archaeal communities varies under different substrate and physicochemical conditions. This review discusses the characteristics of POME, explores the microbial members engaged in each stage of AD, and elucidates the impacts of substrate and physicochemical conditions on the microbial community dynamics, with a specific focus on POME. Finally, the review outlines current research needs and provides future perspectives on optimizing the microbial communities for enhanced biomethane production from oil palm wastes.

2.
J Pharm Policy Pract ; 17(1): 2308617, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38420042

RESUMO

Background: The safety, side effects and efficacy profile of COVID-19 vaccines remain subjects of ongoing concern among the public in Malaysia. The aim of this study was to determine the types of adverse effects following immunisation with COVID-19 vaccines and the differences based on various types of COVID-19 vaccines to raise public awareness and reduce vaccine hesitancy among the public. Methods: A total of 901 Malaysian adults (≥18 years) who received various COVID-19 vaccines were selected to participate in our cross-sectional study through an online survey between December 2021 and January 2022. Results: A total of 814 (90.3%) of the participants reported ≥1 side effect following COVID-19 immunisation. Of these, the predominant symptoms were swelling at the injection site (n = 752, 83.5%), headache (n = 638, 70.8%), pain or soreness at the injection site (n = 628, 69.7%), fatigue or tiredness (n = 544, 60.4%), muscle weakness (n = 529, 58.7%) and diarrhea (n = 451, 50.1%). Recipients of the Pfizer-BioNTech (Comirnaty ®) vaccine reported the highest number of adverse effects (n = 355, 43.6%), followed by mixed COVID-19 vaccines (n = 254, 31.2%), the Oxford-AstraZeneca (ChAdOx1-®[recombinant]) vaccine (n = 113, 13.9%) and the Sinovac (CoronaVac®) vaccine (n = 90, 11.1%). The study showed that individuals who reported significantly more side effects were of elderly age, female gender and high educational level [P value < 0.05]. Mixed COVID-19 vaccine recipients also reported significantly more local and systemic symptoms after the first dose and third dose when compared with other single vaccine recipients. Conclusion: This study demonstrated the types of self-reported adverse effects following immunisation with single and mixed COVID-19 vaccines. These findings may provide the side effects of different COVID-19 vaccines with the hope of educating the public on the safety profiles of these vaccines and reducing vaccine hesitancy among the public.

3.
Microbiol Resour Announc ; 12(12): e0063323, 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-37982654

RESUMO

We report the complete genome sequence of Methylomonas sp. UP202 isolated from an urban waterway sediment in Singapore. The genome contains genes involved in methane, methanol, formaldehyde, and formate oxidation. It also contains genes utilizing various nitrogen sources such as nitrogen, nitrate, nitrite, urea, and ammonium.

4.
Mol Biol Rep ; 50(3): 2367-2379, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36580194

RESUMO

BACKGROUND: The basidiomycete fungus, Ganoderma boninense is the main contributor to oil palm Basal Stem Rot (BSR) in Malaysia and Indonesia. Lanosterol 14α-Demethylase (ERG11) is a key enzyme involved in biosynthesis of ergosterol, which is an important component in the fungal cell membrane. The Azole group fungicides are effective against pathogenic fungi including G. boninense by inhibiting the ERG11 activity. However, the work on molecular characterization of G. boninense ERG11 is still unavailable today. METHODS AND RESULTS: This study aimed to isolate and characterize the full-length cDNA encoding ERG11 from G. boninense. The G. boninense ERG11 gene expression during interaction with oil palm was also studied. A full-length 1860 bp cDNA encoding ERG11 was successfully isolated from G. boninense. The G. boninense ERG11 shared 91% similarity to ERG11 from other basidiomycete fungi. The protein structure homology modeling of GbERG11 was analyzed using the SWISS-MODEL workspace. Southern blot and genome data analyses showed that there is only a single copy of ERG11 gene in the G. boninense genome. Based on the in-vitro inoculation study, the ERG11 gene expression in G. boninense has shown almost 2-fold upregulation with the presence of oil palm. CONCLUSION: This study provided molecular information and characterization study on the G. boninense ERG11 and this knowledge could be used to design effective control measures to tackle the BSR disease of oil palm.


Assuntos
Ganoderma , Arecaceae/genética , Arecaceae/metabolismo , DNA Complementar/genética , DNA Complementar/metabolismo , Ganoderma/genética , Lanosterol/metabolismo , Doenças das Plantas/microbiologia
5.
Plants (Basel) ; 11(11)2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35684239

RESUMO

Essential oils protect plants, and due to their natural origin, there is much interest in using them as antimicrobial agents. The purpose of this study was to determine the phytochemical constituents of ginger essential oil (GEO), antimicrobial activity, and mode of action against Burkholderia glumae (Bg). In addition, the volatile active compounds (AIs) were studied using GC-MS, FTIR, and Raman spectroscopy. A total of 45 phytochemical components were detected and the most prevalent bioactive compounds were Geranial, 1,8-Cineole, Neral, Camphene, α-Zingiberene, and α-Farnesene. Furthermore, it was found that the most dominant terpenes in GEO were monoterpenes. The diameter zone of inhibition values varied from 7.1 to 15 mm depending on the concentration tested. In addition, the MIC and MBC values were 112.5 µL/mL. Faster killing time and lower membrane potential were observed in 1xMIC treatment compared to 0.5xMIC treatment, whereas the control had the maximum values. From observations of various images, it was concluded that the mode of action of GEO affected the cytoplasmic membrane, causing it to lose its integrity and increase its permeability. Therefore, the antibacterial study and mechanism of action revealed that GEO is very effective in suppressing the growth of B. glumae.

6.
Mar Environ Res ; 175: 105589, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35228143

RESUMO

Harmful algal blooms (HABs) were not new to the tropical semi-enclosed Johor Strait, with incident records that could trace back to the 1980s. HAB monitoring in the area, often, is reactive, focusing only on HAB taxa previously causing problems but neglecting potential emerging HABs. To develop datasets on HABs that can better inform and improve management practices, monitoring should expand to sample whole microphytoplankton communities. In this study, microphytoplankton community structure across the Strait was investigated. Abundances of microphytoplankton and a suite of in situ water parameters of temperatures, salinity, pH, dissolved oxygen levels, macronutrients, and chlorophyll-a contents were collected at ten sites across the Strait at monthly intervals from January 2017 to December 2018. A total of 48 genera (51 taxa) microphytoplankton were identified microscopically. Diatom was the most diverse group (32 genera), followed by dinophyte (15 genera). Bloom-forming species included diatoms Chaetoceros, Coscinodiscus, Eucampia, Pseudo-nitzschia, Rhizosolenia, Skeletonema, Thalassiosira, and dinophytes Blixaea quinquecornis and Scrippsiella. Diatom taxa that exhibit high in situ growth rates were predominant in the low-nutrient marine-influenced environment. Bloom-forming taxa including HAB taxa were found dominant in the environment with high nutrient levels and mesohaline, salinity-stratified conditions. This study provides valuable baseline data that could assist in monitoring and prediction of HABs in the Johor Strait and could be of reference to other similar tropical coastal systems.


Assuntos
Diatomáceas , Dinoflagellida , Microalgas , Proliferação Nociva de Algas , Malásia
7.
Bioresour Bioprocess ; 9(1): 16, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38647867

RESUMO

Biohydrogen production through dark fermentation is very attractive as a solution to help mitigate the effects of climate change, via cleaner bioenergy production. Dark fermentation is a process where organic substrates are converted into bioenergy, driven by a complex community of microorganisms of different functional guilds. Understanding of the microbiomes underpinning the fermentation of organic matter and conversion to hydrogen, and the interactions among various distinct trophic groups during the process, is critical in order to assist in the process optimisations. Research in biohydrogen production via dark fermentation is currently advancing rapidly, and various microbiology and molecular biology tools have been used to investigate the microbiomes. We reviewed here the different systems used and the production capacity, together with the diversity of the microbiomes used in the dark fermentation of industrial wastes, with a special emphasis on palm oil mill effluent (POME). The current challenges associated with biohydrogen production were also included. Then, we summarised and discussed the different molecular biology tools employed to investigate the intricacy of the microbial ecology associated with biohydrogen production. Finally, we included a section on the future outlook of how microbiome-based technologies and knowledge can be used effectively in biohydrogen production systems, in order to maximise the production output.

8.
Biology (Basel) ; 10(9)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34571758

RESUMO

Approximately 15-18% of crops losses occur as a result of animal pests, while weeds and microbial diseases cause 34 and 16% losses, respectively. Fungal pathogens cause about 70-80% losses in yield. The present strategies for plant disease control depend transcendently on agrochemicals that cause negative effects on the environment and humans. Nanotechnology can help by reducing the negative impact of the fungicides, such as enhancing the solubility of low water-soluble fungicides, increasing the shelf-life, and reducing toxicity, in a sustainable and eco-friendly manner. Despite many advantages of the utilization of nanoparticles, very few nanoparticle-based products have so far been produced in commercial quantities for agricultural purposes. The shortage of commercial uses may be associated with many factors, for example, a lack of pest crop host systems usage and the insufficient number of field trials. In some areas, nanotechnology has been advanced, and the best way to be in touch with the advances in nanotechnology in agriculture is to understand the major aspect of the research and to address the scientific gaps in order to facilitate the development which can provide a rationale of different nanoproducts in commercial quantity. In this review, we, therefore, described the properties and synthesis of nanoparticles, their utilization for plant pathogenic fungal disease control (either in the form of (a) nanoparticles alone, that act as a protectant or (b) in the form of a nanocarrier for different fungicides), nano-formulations of agro-nanofungicides, Zataria multiflora, and ginger essential oils to control plant pathogenic fungi, as well as the biosafety and limitations of the nanoparticles applications.

10.
Folia Microbiol (Praha) ; 66(4): 677-688, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34041694

RESUMO

The basidiomycete fungus, Ganoderma boninense, has been identified as the main causal agent of oil palm basal stem rot (BSR) disease which has caused significant economic losses to the industry especially in Malaysia and Indonesia. Various efforts have been initiated to understand the disease and this plant pathogen especially at the molecular level. This is the first study of its kind on the development of a polyethylene glycol (PEG)-mediated protoplast transformation system for G. boninense. Based on the minimal inhibitory concentration study, 60 µg/mL and above of hygromycin were effective to completely inhibit G. boninense growth. Approximately 5.145 × 107 cells/mL of protoplasts with the viability of 97.24% was successfully obtained from G. boninense mycelium tissue. The PEG-mediated G. boninense protoplast transformation using 1 µg of transformation vector, 25% of PEG solution, 10 min of pre-transformation incubation, and 30 min of post-transformation incubation has improved the transformation rate as compared with the previous reported protocols for other basidiomycete fungi. Optimization of four transformation parameters has improved the transformation efficiency of G. boninense from an average of 2 to 67 putative transformants. The presence of hygromycin phosphotransferase (hpt) and enhanced green fluorescent protein (eGFP) genes in the putative transformants was detected by PCR and verified by gene sequence analysis. Southern hybridization result further confirmed the integration of hpt gene in G. boninense transformants, and the green fluorescent signal was detected in the G. boninense transformants under the microscopic analysis. The establishment of this transformation system will accelerate the gene function studies of G. boninense especially those genes that may contribute to the pathogenesis of this fungus in oil palm.


Assuntos
Ganoderma , Biologia Molecular , Polietilenoglicóis , Protoplastos , Transformação Genética , Ganoderma/efeitos dos fármacos , Ganoderma/genética , Biologia Molecular/métodos , Polietilenoglicóis/metabolismo , Protoplastos/efeitos dos fármacos , Protoplastos/metabolismo
11.
Environ Sci Pollut Res Int ; 27(34): 42948-42959, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32725555

RESUMO

The Johor Strait has experienced rapid development of various human activities and served as the main marine aquaculture area for the two countries that bordered the strait. Several fish kill incidents in 2014 and 2015 have been confirmed, attributed to the algal blooms of ichthyotoxic dinoflagellates; however, the cause of fish kill events after 2016 was not clarified and the causative organisms remained unknown. To clarify the potential cause of fish kills along the Johor Strait, a 1-year field investigation was conducted with monthly sampling between May 2018 and April 2019. Monthly vertical profiles of physical water parameters (temperature, salinity, and dissolved oxygen levels) were measured in situ at different depths (subsurface, 1 m, 5 m, and 8 m) depending on the ambient depth of the water column at the sampling stations. The spatial-temporal variability of macronutrients and chlorophyll a content was analyzed. Our results showed that high chlorophyll a concentration (up to 48.8 µg/L) and high biomass blooms of Skeletonema, Chaetoceros, Rhizosolenia, and Thalassiosira were observed seasonally at the inner part of the strait. A hypoxic to anoxic dead zone, with the dissolved oxygen levels ranging from 0.19 to 1.7 mg/L, was identified in the inner Johor Strait, covering an estimated area of 10.3 km2. The occurrence of high biomass diatom blooms and formation of the hypoxic-anoxic zone along the inner part Johor Strait were likely the culprits of some fish kill incidents after 2016.


Assuntos
Diatomáceas , Dinoflagellida , Animais , Biomassa , Clorofila A , Eutrofização
12.
RSC Adv ; 10(27): 15800-15814, 2020 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35493652

RESUMO

The first layer of defense that plants deploy to ward off a microbial invasion comes in the form of pattern-triggered immunity (PTI), which is initiated when the pattern-recognition receptors (PRRs) bind with the pathogen-associated molecular patterns (PAMPs) and co-receptor proteins, and transmit a defense signal. Although several plant PRRs have been discovered, very few of them have been fully characterized, and their functional parameters assessed. In this study, the 3D-model prediction of an entire plant PRR protein, Xa21, was done by implementing multiple in silico modeling techniques. Subsequently, the PAMP RaxX21-sY (sulphated RaxX21) and leucine-rich repeat (LRR) domain of the co-receptor OsSERK2 were docked with the LRR domain of Xa21. The docked complex of these three proteins formed a heterodimer that closely resembles the other crystallographic PTI complexes available. Molecular dynamics simulations and MM/PBSA calculations were applied for an in-depth analysis of the interactions between Xa21 LRR, RaxX21-sY, and OsSERK2 LRR. Arg230 and Arg185 from Xa21 LRR, Val2 and Lys15 from RaxX21-sY and Lys164 from OsSERK2 LRR were found to be the prominent residues which might contribute significantly in the formation of a heterodimer during the PTI process mediated by Xa21. Additionally, RaxX21-sY interacted much more favorably with Xa21 LRR in the presence of OsSERK2 LRR in the complex, which substantiates the necessity of the co-receptor in Xa21 mediated PTI to recognize the PAMP RaxX21-sY. However, the free energy binding calculation reveals the favorability of a heterodimer formation of PRR Xa21 and co-receptor OsSERK2 without the presence of PAMP RaxX21-sY, which validate the previous lab result.

13.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-825406

RESUMO

@#A 4-year-old boy complained of dryness of lips for a 3-month duration. The dryness progressed to becoming scaly and painful, and lesions extended beyond the lip area. The condition was associated with peri-oral itchiness. The boy was observed to be licking his lips subconsciously a few times per minute. The lesions started with a habitual licking of the lips. There was no history of allergies or any recent intake of a new drug. There was also no history of atopy in the patient or his family

14.
Pol J Microbiol ; 67(3): 283-290, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30451444

RESUMO

Lower temperature biohydrogen production has always been attractive, due to the lower energy requirements. However, the slow metabolic rate of psychrotolerant biohydrogen-producing bacteria is a common problem that affects their biohydrogen yield. This study reports on the improved substrate synthesis and biohydrogen productivity by the psychrotolerant Klebsiella sp. strain ABZ11, isolated from Antarctic seawater sample. The isolate was screened for biohydrogen production at 30°C, under facultative anaerobic condition. The isolate is able to ferment glucose, fructose and sucrose with biohydrogen production rate and yield of 0.8 mol/l/h and 3.8 mol/g, respectively at 10 g/l glucose concentration. It also showed 74% carbohydrate uptake and 95% oxygen uptake ability, and a wide growth temperature range with optimum at 37°C. Klebsiella sp. ABZ11 has a short biohydrogen production lag phase, fast substrate uptake and is able to tolerate the presence of oxygen in the culture medium. Thus, the isolate has a potential to be used for lower temperature biohydrogen production process.


Assuntos
Temperatura Baixa , Hidrogênio/metabolismo , Klebsiella/metabolismo , Regiões Antárticas , Metabolismo dos Carboidratos , Carboidratos , Meios de Cultura/química , Fermentação , Concentração de Íons de Hidrogênio , Klebsiella/genética , Oxigênio/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Água do Mar/microbiologia
15.
J Microbiol Immunol Infect ; 50(4): 427-434, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26427880

RESUMO

BACKGROUND/PURPOSE: Currently, silver nanoparticles (AgNPs) have gained importance in various industrial applications. However, their impact upon release into the environment on microorganisms remains unclear. The aim of this study was to analyze the effect of polyvinylpyrrolidone-capped AgNPs synthesized in this laboratory on two bacterial strains isolated from the environment, Gram-negative Citrobacter sp. A1 and Gram-positive Enterococcus sp. C1. METHODS: Polyvinylpyrrolidone-capped AgNPs were synthesized by ultrasound-assisted chemical reduction. Characterization of the AgNPs involved UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. Citrobacter sp. A1 and Enterococcus sp. C1 were exposed to varying concentrations of AgNPs, and cell viability was determined. Scanning electron microscopy was performed to evaluate the morphological alteration of both species upon exposure to AgNPs at 1000 mg/L. RESULTS: The synthesized AgNPs were spherical in shape, with an average particle size of 15 nm. The AgNPs had different but prominent effects on either Citrobacter sp. A1 or Enterococcus sp. C1. At an AgNP concentration of 1000 mg/L, Citrobacter sp. A1 retained viability for 6 hours, while Enterococcus sp. C1 retained viability only for 3 hours. Citrobacter sp. A1 appeared to be more resistant to AgNPs than Enterococcus sp. C1. The cell wall of both strains was found to be morphologically altered at that concentration. CONCLUSION: Minute and spherical AgNPs significantly affected the viability of the two bacterial strains selected from the environment. Enterococcus sp. C1 was more vulnerable to AgNPs, probably due to its cell wall architecture and the absence of silver resistance-related genes.


Assuntos
Antibacterianos/farmacologia , Citrobacter/efeitos dos fármacos , Enterococcus/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Nanopartículas/química , Povidona/farmacologia , Prata/farmacologia , Citrobacter/isolamento & purificação , Citrobacter/fisiologia , Enterococcus/isolamento & purificação , Enterococcus/fisiologia , Microbiologia Ambiental , Microscopia Eletrônica , Oxirredução , Análise Espectral , Ultrassonografia , Difração de Raios X
16.
Nutrients ; 8(3): 95, 2016 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-26927161

RESUMO

Diabetic dyslipidemia contributes to an increased risk of cardiovascular disease. Hence, its treatment is necessary to reduce cardiovascular events. Honey reduces hyperglycemia and dyslipidemia. The reproducibility of these beneficial effects and their generalization to honey samples of other geographical parts of the world remain controversial. Currently, data are limited and findings are inconclusive especially with evidence showing honey increased glycosylated hemoglobin in diabetic patients. It was hypothesized that this deteriorating effect might be due to administered high doses. This study investigated if Nigerian honey could ameliorate hyperglycemia and hyperlipidemia. It also evaluated if high doses of honey could worsen glucose and lipid abnormalities. Honey (1.0, 2.0 or 3.0 g/kg) was administered to diabetic rats for three weeks. Honey (1.0 or 2.0 g/kg) significantly (p < 0.05) increased high density lipoprotein (HDL) cholesterol while it significantly (p < 0.05) reduced hyperglycemia, triglycerides (TGs), very low density lipoprotein (VLDL) cholesterol, non-HDL cholesterol, coronary risk index (CRI) and cardiovascular risk index (CVRI). In contrast, honey (3.0 g/kg) significantly (p < 0.05) reduced TGs and VLDL cholesterol. This study confirms the reproducibility of glucose lowering and hypolipidemic effects of honey using Nigerian honey. However, none of the doses deteriorated hyperglycemia and dyslipidemia.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Experimental/prevenção & controle , Dislipidemias/prevenção & controle , Mel , Lipídeos/sangue , Aloxano , Animais , Biomarcadores/sangue , Peso Corporal , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/induzido quimicamente , Dislipidemias/sangue , Dislipidemias/induzido quimicamente , Nigéria , Ratos Wistar , Medição de Risco , Fatores de Risco
17.
J Immigr Minor Health ; 17(4): 1114-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24946936

RESUMO

Respiratory illness were a major problem and caused high hospital admission during hajj seasons. One of the contributing cause to this illness is infection. Various measures had been implemented to reduce respiratory infections. The aim on the study is to determine the effect of influenza vaccination against acute respiratory illness among Malaysian Hajj pilgrims. This is an observational cohort study. Influenza vaccination was given to pilgrims at least 2 weeks prior to departure. The occurrence of symptoms for respiratory illness such as cough, fever, sore throat and runny nose was monitored daily for 6 weeks during pilgrimage using a health diary. A total of 65 vaccinated hajj pilgrims and 41 controls were analyzed. There was no significant difference in pattern of occurrence of symptoms of respiratory illness by duration of pilgrimage as well as the number of symptoms between both groups. Hajj pilgrims have frequent respiratory symptoms. We were unable to document benefit from influenza vaccination, but our study was limited by a small sample size and lack of laboratory testing for influenza.


Assuntos
Vacinas contra Influenza/uso terapêutico , Doenças Respiratórias/epidemiologia , Viagem/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Islamismo , Malásia/etnologia , Masculino , Pessoa de Meia-Idade , Doenças Respiratórias/prevenção & controle , Arábia Saudita/epidemiologia , Adulto Jovem
18.
Org Biomol Chem ; 11(4): 612-20, 2013 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-23208549

RESUMO

Human lysyl-tRNA synthetase (hLysRS) is known to interact directly with human immunodeficiency virus type-1 (HIV-1) GagPol polyproteins, and both hLysRS with tRNA(Lys3) are selectively packaged into emerging HIV-1 viral particles. This packaging process appears to be mediated by contact between the motif 1 helix h7 of hLysRS and the C-terminal dimerization domain of the HIV-1 capsid protein (CA) segment of Gag or GagPol. Given similarities between hLysRS and Escherichia coli (E. coli) heat shock protein LysU, we investigate if LysU might be an hLysRS surrogate for interactions with Gag or GagPol proteins. We report on a series of studies involving three CA C-domains: CA(146) (intact domain), CA(151) (truncated domain), and CA(146)-M185A (M185A, CA dimer interface mutant). After confirming that LysU and CA(146) are dimeric whilst CA(151) and M185A remain monomeric, we use glutathione S-transferase (GST) pull-down assays to demonstrate the existence of specific interactions between LysU and all three CA-C domains. By means of (1)H-NMR titration experiments, we estimate K(d) values of 50 µM for the interaction between LysU and CA(146) or >500 µM for interactions between LysU and CA(151) or LysU and M185A. The reason for these binding affinity differences may be that interactions between LysU and CA(146) take place through dimer-dimer interactions resulting in a α(2)ß(2) heterotetramer. LysU/CA-C protein interactions are weaker than those reported between hLysRS and the Gag, CA or CA(146) proteins, and hLysRS/Gag binding interactions have also been suggested to involve only αß heterodimer formation. Nevertheless, we propose that LysU could act as a surrogate for hLysRS with respect to Gag and GagPol polyprotein interactions although arguably not sufficiently for LysU to act as an inhibitor of the HIV-1 life cycle without further adaptation or mutation. Potentially, LysU and/or LysU mutants could represent a new class of anti-HIV-1 therapeutic agent.


Assuntos
Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli , HIV-1/metabolismo , Lisina-tRNA Ligase/metabolismo , Motivos de Aminoácidos , Proteínas de Transporte/química , Proteínas de Escherichia coli/química , Humanos , Isoenzimas/química , Isoenzimas/metabolismo , Lisina-tRNA Ligase/química , Modelos Moleculares , Ligação Proteica , Multimerização Proteica , Estrutura Quaternária de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos
19.
J Biol Chem ; 288(6): 4452-61, 2013 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-23212911

RESUMO

Heat shock protein 47 (HSP47) is a single-substrate molecular chaperone crucial for collagen biosynthesis. Although its function is well established, the molecular mechanisms that govern binding to procollagen peptides and triple helices in the endoplasmic reticulum (followed by controlled release in the Golgi) are unclear. HSP47 binds procollagen at a neutral pH but releases at a pH similar to the pK(a) of the imidazole side chain of histidine residues. It thus seems likely that these residues are involved in this pH-dependent mechanism. Murine HSP47 has 14 histidine residues grouped into three clusters, known as the breach, gate, and shutter. Here, we report the use of histidine mutagenesis to demonstrate the relative contribution of these three clusters to HSP47 structure and the "pH switch." Many of the tested mutants are silent; however, breach mutants H197A and H198A show binding but no apparent pH switch and are unable to control release. Another breach mutant, H191A, shows perturbed collagen release characteristics, consistent with observed perturbations in pH-driven trans-conformational changes. Thus, His-198, His-197 and His-191 are important (if not central) to HSP47 mechanism of binding/release to collagen. This is consistent with the breach cluster residues being well conserved across the HSP47 family.


Assuntos
Proteínas de Choque Térmico HSP47/química , Histidina/química , Mutação de Sentido Incorreto , Pró-Colágeno/química , Substituição de Aminoácidos , Animais , Proteínas de Choque Térmico HSP47/genética , Proteínas de Choque Térmico HSP47/metabolismo , Histidina/genética , Histidina/metabolismo , Concentração de Íons de Hidrogênio , Camundongos , Mapeamento de Peptídeos/métodos , Pró-Colágeno/genética , Pró-Colágeno/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína
20.
Forensic Sci Int ; 223(1-3): 53-63, 2012 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-22955030

RESUMO

Most of the automotive companies use cast iron for their engine blocks. Restoration of obliterated number on these iron surfaces by chemical etching is known to be quite difficult. Heating of the obliterated surface using oxyacetylene flame is an alternative recovery treatment suggested in literature and used in practice. However chemical etching has been established to be the most sensitive technique for detection of metal deformation present under stamped serial numbers. Hence, the current work investigated the suitability of some common etchants on cast iron surfaces with a view to determining the most suitable one for revealing the obliterated marks. The reagents tested were mostly copper containing Fry's reagent and its modifications. Two cast iron engine blocks (3.29%C and 3.1%C) of two cars--a Proton Saga and a Toyota--were utilized for the experiments. The engine blocks were cut into several small plates and each plate was stamped with some numerical characters at 8 kN load using Instron Table Mounted Universal Testing Machine. The depth of stamping impression varied between 0.2 mm and 0.3 mm. The stamped number was completely ground off manually using a metal file. The grounded surface was then polished smooth using emery papers and etched with a few selected reagents mostly by swabbing. Experimental results showed that a modified Fry's composition consisting of 4 5g CuCl(2), 100 mL HCl, and 180 mL H(2)O restored the number with better contrast at a reasonably shorter time. The above reagent is a slightly modified form of one of the Fry's original compositions--45 g CuCl(2), 180 mL HCl, and 100 mL H(2)O. Quite importantly the proposed reagent restored the original stamped numbers of both Proton and Toyota cars and also a Mitsubishi car that had been obliterated. The most widely used Fry's composition (90 g CuCl(2), 120 mL HCl and 100 mL H(2)O), although recovered the obliterated number, did not cause the desired contrast.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...