Quantificação de erros de incorporação em proteínas recombinantes

Mestrado em Biologia Molecular CelularA síntese de proteínas de acordo com o código genético é essencial para manter proteoma estável e para a homeostase celular. No entanto, os erros podem ocorrer naturalmente durante a síntese da proteína a partir do seu mRNA, variando entre 10-3 a 10-4 erros por codão. Estes erros ocorrem com mais frequncia em proteínas recombinantes sobre-expressas em hospedeiros heterólogos. Quantidades crescentes de proteína não-funcional estão geralmente relacionados à tradução em condições de stress. Neste estudo utilizou-se Saccharomyces cerevisiae como um organismo hospedeiro para expressar o gene lacZ-GST para quantificar o erro de tradução. A levedura foi tratada com diversos agentes de stress tais como o etanol, o crómio (CrO3), e aminoglicósido antibiótico - geneticina (G418). A incorporação de erros foi estudada em proteína solúvel e insolúvel para determiner se os erros de tradução aumentam a agregação de proteína. Usando esta abordagem, verificou-se que o stress aumenta o erro de tradução para níveis de 5.6 × 10-3 a 8 × 10-3, 60 - 80 vezes mais que o nível normal. Esta taxa de erro inesperadamente elevada tem implicações para a utilização terapêutica de proteínas recombinantes.The synthesis of protein according to genetic code of a gene determines the basis of life and a stable proteome is necessary for cell homeostatis. Faithful translation of protein give gurantee of cell survival. However, errors occur naturally during translation of protein from its mRNA, which varies from 10-3 to 10-4 per codon. These errors are more frequent in recombinant protein overexpressed in heterologous hosts and affect protein functionality. The increasing amount of nonfunctional protein is often related to mistranslation of a gene under stress. In the present study, we used Saccharomyces cerevisiae as a host organism to overexpress E. coli lacZ gene fusion with GST to quantify misincorporation of amino acid in GST-β galactosidase recombinant protein. The yeast was treated with various stressors such as ethanol, chromium (CrO3), and aminoglycoside antibiotic - geneticin (G418) to induce protein aggregation. The misincorporation of amino acids was studied in both soluble and insoluble protein fractions by mass-spectrometry to determine how much misincorporation occur and whether this is associated with protein insolubility. We found that under experimental stress conditions the misincorporation of amino acids ranges from 5.6 × 10-3 to 8 × 10-3, which represents 60-80 fold higher than reported level. The unexpectedly high error rate has implications for the therapeutic use of the heterologous host derived recombinant proteins

Effective composting of oil palm industrial waste by filamentous fungi: A review.

Palm oil production is a major agricultural industry in Malaysia, in which palm oil mill effluent (POME) and oil palm empty fruit bunch (EFB) are considered as major waste products from the palm oil industry. These waste products create an environmental hazard and entail high disposal costs every year. Composting is a biologically based process which is practiced to stabilize the organic matter for soil amendment (producing compost) and to protect the environment from the detrimental effects of these waste products. This study reviews the composting process of EFB and POME as a single substrate and/or their mixture by using potential filamentous fungi that are especially lignocellulolytic and antibiotic (in a matured stage) in nature within several effective parameters, for example, C/N ratio, moisture content, pH, temperature, etc. Several studies record the mature composting process as being 60 days. In most cases, temperature and moisture content was maintained up to 70 °C and 60–75%, respectively. In addition, this study reviews EFB and POME with their constituents for an efficient composting process

Multilocus Microsatellite Typing reveals intra-focal genetic diversity among strains of Leishmania tropica in Chichaoua Province, Morocco

AbstractIn Morocco, cutaneous leishmaniasis (CL) caused by Leishmania (L.) tropica is a major public health threat. Strains of this species have been shown to display considerable serological, biochemical, molecular biological and genetic heterogeneity; and Multilocus Enzyme Electrophoresis (MLEE), has shown that in many countries including Morocco heterogenic variants of L. tropica can co-exist in single geographical foci. Here, the microsatellite profiles discerned by MLMT of nine Moroccan strains of L. tropica isolated in 2000 from human cases of CL from Chichaoua Province were compared to those of nine Moroccan strains of L. tropica isolated between 1988 and 1990 from human cases of CL from Marrakech Province, and also to those of 147 strains of L. tropica isolated at different times from different worldwide geographical locations within the range of distribution of the species. Several programs, each employing a different algorithm, were used for population genetic analysis. The strains from each of the two Moroccan foci separated into two phylogenetic clusters independent of their geographical origin. Genetic diversity and heterogeneity existed in both foci, which are geographically close to each other. This intra-focal distribution of genetic variants of L. tropica is not considered owing to in situ mutation. Rather, it is proposed to be explained by the importation of pre-existing variants of L. tropica into Morocco

A proposed resistance-to-time converter with switching impulse calibrators for resistive bridge sensors

This paper presents a simple resistance-to-time converter. It consists of two voltage comparators, a ramp voltage generator, two logic gates and impulse voltage calibrators. A square-wave generator circuit is suggested in this paper. The design is simple and independent of the OPAMP offset issues. The resulting square-wave is rectified to get its DC equivalent and to a triangular output; the two outputs are applied to a comparator for generating a digital output with duty cycle proportional to a change in resistance upon which is dependent the DC

Various risks and safety analysis to reduce fire in oil refinery plant

It is quite hazardous to produce the final product of oil or gas in a petrochemical refinery plant due to its flammable or combustible and explosive materials. Small mistakes can cause massive damage to life, property, pollution, injury, ecosystem, and business by fire. The entire system is challenging to manage. Therefore, fire risk assessment and forecasting are necessary to overcome personal, environmental, and refinery plants' hazard situations. There have been four main threats in any refinery facility: electrical, mechanical, civil, and chemical issues, maximum cases its result burning. This research aimed to study and assess fire risk in the refinery plant by using a multi-stage early warning system and reducing the fire. The fire hazard safety layer technique would be used for our petrochemical process. Some equipment is set in place to forecast the danger and execution before and after it happens. Geographic information systems (GIS), remote sensing (RS) are some techniques for fire incidents tracking. Flame detectors, heat detectors, and gas detectors are used to maintain good contact in the entire risk analyzer portion. Various techniques and monitoring have been proposed to operate the plant efficiently and safely, like controlling, predicting, and pre-warning strategic planning

Avirulence gene based RFLP and rep-PCR distinguish the genetic variation of Xanthomonas oryzae pv. oryzae pathotypes in Bangladesh

Bacterial blight (BB) caused by X. oryzae pv. oryzae is one of the devastating diseases of rice mostly in Asia. Genomes of X. oryzae pv. oryzae is highly variable due to rearrangement of the large contents of transposable elements and dynamic changes of X. oryzae pv. oryzae population regulated efficiency of the control measures used for BB management of rice worldwide. In this study, genetic variation of X. oryzae pv. oryzae pathotypes of Bangladesh was studied using aviruelnce gene based RFLP and rep-PCR techniques aimed to formulate pathogen targeted effective control measures against BB of rice. Eight pathotypes of X. oryzae pv. oryzae field isolates were identified based on their reactions against 10 Near Isogenic Lines (NILs). Among eight pathotypes, pathotypes IV and V contained higher number of isolates which were 30.13% and 23.01% respectively while pathotype VIII revealed as minimum containing only 2.51% of total isolates. These eight pathotypes were studied for their genetic variation by RFLP using avrBs3 repeat domain as probe. The results conceded that Bangladeshi X. oryzae pv. oryzae strains seem carrying a minimum of two and maximum of nine avrBs3 family genes homologs. The resistance phenotype on IRBB7 and IRBB10 NILs also indicated presence of two major avrBs3 family genes viz. avrxa7 and avrXa10 in some pathotypes. Relationship of phylogenicity exhibited that X. oryzae pv. oryzae pathotypes assorted into two RFLP haplotypes as well as these haplotypes are largely distributed in Bangladesh. Phylogenetic analyses carried out by (REP, ERIC), rep-PCR and BOX depicted the presence of two main molecular haplotypes of X. oryzae pv. oryzae pathotypes. The relationship between pathotypes and molecular haplotypes of X. oryzae pv. oryzae in Bangladesh indicated that the same lineage possesses different pathotypes and different lineage possesses different pathotypes. The results indicated that eight different pathotypes might have originated from common inherited haplotypes with a wide genetic variation

Microbial lipid extraction from Lipomyces starkeyi using irreversible electroporation

The aim of the study was to investigate the feasibility of using irreversible electroporation (EP) as a microbial cell disruption technique to extract intracellular lipid within short time and in an eco-friendly manner. An EP circuit was designed and fabricated to obtain 4 kV with frequency of 100 Hz of square waves. The yeast cells of Lipomyces starkeyi (L. starkeyi) were treated by EP for 2-10 min where the distance between electrodes was maintained at 2, 4, and 6 cm. Colony forming units (CFU) were counted to observe the cell viability under the high voltage electric field. The forces of the pulsing electric field caused significant damage to the cell wall of L. starkeyi and the disruption of microbial cells was visualized by field emission scanning electron microscopic (FESEM) image. After breaking the cell wall, lipid was extracted and measured to assess the efficiency of EP over other techniques. The extent of cell inactivation was up to 95% when the electrodes were placed at the distance of 2 cm, which provided high treatment intensity (36.7 kWh m ). At this condition, maximum lipid (63 mg g ) was extracted when the biomass was treated for 10 min. During the comparison, EP could extract 31.88% lipid while the amount was 11.89% for ultrasonic and 16.8% for Fenton's reagent. The results recommend that the EP is a promising technique for lowering the time and solvent usage for lipid extraction from microbial biomass. © 2018 American Institute of Chemical Engineers Biotechnol

Wide variation of heterozygotic genotypes of recent fasciolid hybrids from livestock in Bangladesh assessed by rDNA internal transcribed spacer region sequencing and cloning

Fascioliasis causes high economic losses in livestock and underlies public health problems in rural areas, mainly of low-income countries. The increasing animal infection rates in Bangladesh were assessed, by focusing on host species, different parts of the country, and rDNA sequences. Fasciolid flukes were collected from buffaloes, cattle, goats and sheep from many localities to assess prevalences and intensities of infection. The nuclear rDNA internal transcribed spacer (ITS) region including ITS-1 and ITS-2 spacers was analyzed by direct sequencing and cloning, given the detection of intermediate phenotypic forms in Bangladesh. The 35.4% prevalence in goats and 55.5% in buffaloes are the highest recorded in these animals in Bangladesh. In cattle (29.3%) and sheep (26.8%) prevalences are also high for these species. These prevalences are very high when compared to lowlands at similar latitudes in neighboring India. The high prevalences and intensities appear in western Bangladesh where cross-border importation of animals from India occur. The combined haplotype CH3A of Fasciola gigantica widely found in all livestock species throughout Bangladesh fits its historical connections with the western Grand Trunk Road and the eastern Tea-Horse Road. The “pure” F. hepatica sequences only in clones from specimens showing heterozygotic positions indicate recent hybridization events with local “pure” F. gigantica, since concerted evolution did not yet have sufficient time to homogenize the rDNA operon. The detection of up to six different sequences coexisting in the cloned specimens evidences crossbreeding between hybrid parents, indicating repeated, superimposed and rapidly evolving hybridization events. The high proportion of hybrids highlights an increasing animal infection trend and human infection risk, and the need for control measures, mainly concerning goats in household farming management. ITS-1 and ITS-2 markers prove to be useful for detecting recent hybrid fasciolids. The introduction of a Fasciola species with imported livestock into a highly prevalent area of the other Fasciola species may lead to a high nucleotide variation in the species-differing positions in the extremely conserved fasciolid spacers. Results suggest that, in ancient times, frequent crossbreeding inside the same Fasciola species gave rise to the very peculiar characteristics of the present-day nuclear genome of both fasciolids