Advances of polymer-monomer production by cyanobacterial cell factory / 生物工程学报

Cyanobacteria is one of the promising microbial chassis in synthetic biology, which serves as a typical host for light-driven production. With the gradual depletion of fossil resources and intensification of global warming, the research on cyanobacterial cell factory using CO2 as carbon resource is ushering in a new wave. For a long time, research focus on cyanobacterial cell factory has mainly been the production of energy products, such as liquid fuels and hydrogen. One of the critical bottlenecks occurring in cyanobacterial cell factory is the poor economic performance, which is mainly caused by the inherent inefficiency of cyanobacteria. The problem is particularly prominent for these extremely cost-sensitive energy products. As an indispensable basis for modern industry, polymer monomers belong to the bulk chemicals with high added value. Therefore, increasing attention has been focused on polymer monomers which are superior in overcoming the economic barrier in commercialization of cyanobacterial cell factories. Here, we systematically review the progress on the production of polymer monomers using cyanobacteria, including the strategies for improving production, and the related technologies for the application of this important microbial cell factory. Finally, we summarize several issues in cyanobacterial synthetic biology and proposed future developing trends in this field.

Research progress of phase separation of intracellular biological macromolecules / 生物工程学报

The phenomenon of phase separation of intracellular biological macromolecules is an emerging research field that has received great attention in recent years. As an aggregation and compartment mechanism of cell biochemical reactions, it widely exists in nature and participates in important physiological processes such as gene transcription and regulation, as well as influences organism's response to external stimuli. Disequilibrium of phase separation may lead to the occurrence of some major diseases. Researchers in cross-cutting fields are trying to examine dementia and other related diseases from a new perspective of phase separation, exploring its molecular mechanism and the potential possibility of intervention and treatment. This review intends to introduce the latest research progress in this field, summarize the major research directions, biochemical basis, its relationship with disease occurrence, and giving a future perspective of key problems to focus on.

Spondias mombin L. [Anacardiaceae] enhances detoxification of hepatic and macromolecular oxidants in acetaminophen-intoxicated rats

Oxidative stress is a common pathological condition associated with drug-induced hepatotoxicity. This study investigated Spondias mombin L. aqueous leaf extract on reactive oxygen species and acetaminophen-mediated oxidative onslaught in rats' hepatocytes. Hepatotoxic rats were orally administered with the extract and vitamin C for 4 weeks. The extract dose-dependently scavenged DPPH, hydrogen peroxide and hydroxyl radicals, with ICso values of 0.13, 0.66, and 0.64 mg/mL, and corresponding % inhibitions of 89, 80, and 90%, respectively at 1.0 mg/mL. Ferric ion was also significantly reduced. The marked [p<0.05] increases in the activities of alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase were reduced following treatment with the extract. The extract also significantly [p<0.05] induced the activities of antioxidant enzymes. These inductions reversed the acetaminophen-erihanced reduction in the specific activities of these enzymes as well as attenuated the observed elevated concentrations of auto-oxidized products and rived DNA in the acetaminophen-intoxicated animals. The observed effects competed with those of vitamin C and are suggestive of hepatoprotective and antioxidative attributes of the extract. Overall, the data from the present findings suggest that S. Mombin aqueous leaf extract is capable of ameliorating acetaminophen-mediated oxidative hepatic damage via enhancement of antioxidant defense systems.

A local-optimization refinement algorithm in single particle analysis for macromolecular complex with multiple rigid modules

Single particle analysis, which can be regarded as an average of signals from thousands or even millions of particle projections, is an efficient method to study the three-dimensional structures of biological macromolecules. An intrinsic assumption in single particle analysis is that all the analyzed particles must have identical composition and conformation. Thus specimen heterogeneity in either composition or conformation has raised great challenges for high-resolution analysis. For particles with multiple conformations, inaccurate alignments and orientation parameters will yield an averaged map with diminished resolution and smeared density. Besides extensive classification approaches, here based on the assumption that the macromolecular complex is made up of multiple rigid modules whose relative orientations and positions are in slight fluctuation around equilibriums, we propose a new method called as local optimization refinement to address this conformational heterogeneity for an improved resolution. The key idea is to optimize the orientation and shift parameters of each rigid module and then reconstruct their three-dimensional structures individually. Using simulated data of 80S/70S ribosomes with relative fluctuations between the large (60S/50S) and the small (40S/30S) subunits, we tested this algorithm and found that the resolutions of both subunits are significantly improved. Our method provides a proof-of-principle solution for high-resolution single particle analysis of macromolecular complexes with dynamic conformations.

Género y trayectorias profesionales de las médicas de familia en Andalucía, España, a comienzos del siglo XXI / Gender and career paths of female primary care physicians in Andalusia, Spain, at the beginning of 21st century

El objetivo de este trabajo es estudiar, desde una perspectiva feminista, la diversidad y homogeneidad en las trayectorias profesionales de las médicas de familia que ejercían en Andalucía a comienzos del siglo XXI, a través del análisis de los significados que ellas mismas confieren a su desarrollo profesional y de la influencia de los factores personales, familiares y laborales. Realizamos un estudio cualitativo con seis grupos de discusión. Participaron 32 médicas de familia que se encontraban trabajando en los centros de salud urbanos de la red sanitaria pública de Andalucía. El análisis del discurso revela que la mayoría de las médicas no planifican sus metas profesionales y que, cuando lo hacen, las van entrelazando con las necesidades familiares. Esto se traduce en que sus trayectorias profesionales sean discontinuas. Por el contrario, las trayectorias orientadas al desarrollo profesional y a la planificación consciente de metas son más frecuentes entre las médicas que ocupan cargos de dirección en centros de salud.

The purpose of this article was to study, from a feminist perspective, the diversity and homogeneity in the career paths of female primary care physicians from Andalusia, Spain in the early 21st century, by analyzing the meanings they give to their careers and the influence of personal, family and professional factors. We conducted a qualitative study with six discussion groups. Thirty-two female primary care physicians working in urban health centers of the public health system of Andalusia participated in the study. The discourse analysis revealed that most of the female physicians did not plan for professional goals and, when they did plan for them, the goals were intertwined with family needs. Consequently, their career paths were discontinuous. In contrast, career paths oriented towards professional development and the conscious planning of goals were more common among the female doctors acting as directors of health care centers.

Complementary data on four methods for sampling free-living ticks in the Brazilian Pantanal / Dados complementares de quatro métodos para amostragem de carrapatos em vida livre no Pantanal brasileiro

In this study, four methods for sampling free-living ticks that are used in ecological and human tick-bite risk studies were evaluated. Cloth dragging, carbon dioxide traps and visual searches and inspection of plant litter on the ground were used in field and forest areas within the Brazilian Pantanal. Among the three tick species collected, Amblyomma sculptum predominated, followed by Amblyomma parvum and Amblyomma ovale. Dragging, a cheap and simple technique, yielded the highest numbers of ticks, particularly nymphs. The visual search detected a high number of adult ticks and provided information on tick questing height. Even though laborious, plant litter examination showed that large numbers of ticks may use this stratum. Carbon dioxide (CO2) traps are expensive and difficult to handle, but they are highly efficient for adult ticks, especially A. parvum. These data indicate that one method alone is incapable of providing a representative sample of the tick fauna in a particular area and that multiple techniques should be used for tick population studies.

Neste estudo, foram avaliados quatro métodos de amostragem de carrapatos em vida livre, usados em estudos ecológicos e avaliação do risco de picadas em humanos. Arraste de flanela, armadilhas de gás carbônico (CO2), busca visual e inspeção de serrapilheira foram aplicados em áreas campestres e florestais no Pantanal brasileiro. Dentre três espécies coletadas, a predominância foi de Amblyomma sculptum, seguida por Amblyomma parvum e Amblyomma ovale. O arraste, técnica simples e de baixo custo, resultou em maior número de carrapatos, particularmente de ninfas. A busca visual detectou alto número de carrapatos adultos e forneceu informações sobre altura de espera por hospedeiros. Apesar de trabalhoso, o exame da serrapilheira demonstrou que grande número de carrapatos pode utilizar esse estrato. Armadilhas de CO2 têm custo elevado e são difíceis de manusear, entretanto, são altamente eficientes para carrapatos adultos, em especial para A. parvum. Esses dados indicam que somente um método é incapaz de fornecer amostra representativa da ixodofauna em uma área particular e que, para estudos populacionais, técnicas múltiplas devem ser usadas.

Interacciones moleculares de un flavonoide prenilado con transportadores de antimicóticos dependientes de ATP / Molecular interactions of a prenylated flavonoid with ATP-depending antimycotic transporters

Uno de los principales mecanismos para la resistencia de Candida albicans a azoles es la sobreexpresión de transportadores que extruyen los fármacos antimicóticos y disminuyen su concentración intracelular. Anteriormente nuestros laboratorios habían informado que el flavonoide prenilado 2', 4'-dihidroxi - 5'-(1'''-dimetilalil)-6-prenil pinocembrina (6PP) inhibe en forma competitiva los transportadores cdr, dependientes del ATP, además de ser antimicrobiano per se. En este trabajo realizamos estudios bioinformáticos para analizar los posibles sitios de interacción molecular estereoespecífica del 6PP, fluconazol y adenosín trifosfato (ATP) con los transportadores cdr1 y cdr2. Se confeccionaron los modelos tridimensionales de los ligandos y de los transportadores a través de estudios de homología de datos respecto de otras macromoléculas. Se calculó la variación de energía libre de Gibbs ( G) asociada a 45 modelos de interacción molecular y se estudiaron cdr1 y cdr2 en formacomparativa, dada su similitud estructural. Se seleccionaron los modelos más probables desde el punto de vista termodinámico. El 6PP y el fluconazol podrían competir de diversas maneras por un sitio estereoespecífico que atraviesa la membrana de la levadura. Este sitio, numerado como 1, fue estudiado exhaustivamente, es común a los transportadores cdr1 y cdr2 y aporta selectivamente distintosaminoácidos. Entre estos últimos, los de mayor participación en los modelos de interacción fueron, en cdr1 y cdr2, respectivamente: PHE 754,756 y TYR 747,749 . Se seleccionaron los 9 mejores complejos formados por cada ligando, de acuerdo a su energía de afinidad decreciente (en KJ/mol en mejor modelo de cdr2: 6PP = -9,3; fluconazol = -6,8). Además el flavonoide prenilado competiría con el ATP en el dominio citosólico y con menor probabilidad lo imitaría el fluconazol ( G en KJ/mol en mejor modelo de cdr2: 6P P= -8,2, ATP = -7,6; fluconazol = -6,7)...

Current progress in research on the nanomaterials for biological macromolecules recognition / 生物医学工程学杂志

The combination of nanotechnology and molecular imprinting technique, including their application research in biomedical domain, provides a new solution to the problem of the substitutes for antibodies, enzymes, and other native biological structures as well as cell bracket materials. Nanocavity biomaterials with recognition specificity imprinted by using proteins as templates have numerous applications in biotechnology, medicine and so on. This review presents the aspects of molecular imprinting nanostructure involved in the biomacromolecules imprinting, and it explores the precent developments and achievements of nanomaterials for molecular imprinting technology.

Analysis of two drying methods on the yield and activity of sulfated polysaccharides extracted from Halymenia sp (Rhodophyceae) / Análise de dois métodos de secagem sobre o rendimento e atividade de polissacarídeos sulfatados extraídos da rodofícea Halymenia sp

Sulfated polysaccharides (SPs) have attracted growing interest for various biotechnological applications. We evaluated the efficiency of two methods of drying SPs (M I and II) extracted from Halymenia sp Rhodophyceae in order to compare the yield, purification and anticoagulant activity. The total SPs (TSPs) were first extracted with papain in 100 mM sodium acetate (pH 5.0) containing cysteine and EDTA (5 mM). The TSPs obtained were dried in an oven (M I) or lyophilized (M II) and then examined by ion exchange chromatography (DEAE-cellulose) using the NaCl gradient technique. The fractions were analyzed by 0.5% agarose gel electrophoresis and the in vitro anticoagulant activity was evaluated by the activated partial thromboplastin time test using normal human plasma and compared to heparin (HEP) (193.00 IU mg-1). There was a difference in TSP yield of 19.05% and similar chromatographic SP profiles. Electrophoresis revealed fractions with distinct resolutions. The fractions eluted with 0.75 M of salt (M I and II) were the most active, measuring 27.40 and 72.66 IU mg-1, respectively, when compared to HEP. Therefore, obtaining SP with anticoagulant activity from Halymenia sp. is more efficient by freeze-drying.

Os polissacarídeos sulfatados (PS) têm despertado interesse crescente para diversas aplicações em biotecnologia. Avaliou-se a eficiência de duas metodologias de secagem de PSs (M I e II) extraídos da rodofícea Halymenia sp. a fim de se comparar o rendimento, a purificação e a atividade anticoagulante. Inicialmente, os PS totais (PSTs) foram extraídos com papaína em tampão acetato de sódio 100 mM (pH 5,0) contendo cisteína e EDTA (5 mM). Os PSTs foram secados em estufa (M I) ou liofilizados (M II), seguido por cromatografia de troca iônica (DEAE-celulose) utilizando um gradiente de NaCl. As frações foram analisadas por eletroforese em gel de agarose a 0,5% e a atividade anticoagulante "in vitro" avaliada por meio do teste do tempo de tromboplastina parcial ativada usando plasma humano normal e comparadas à heparina (HEP) (193.00 UI mg-1). Verificaram-se diferença no rendimento de PSTs (19,05%) e semelhantes perfis cromatográficos de PS, revelando, por eletroforese, frações de PS distintas em grau de resolução entre os métodos. As frações eluídas com 0,75 M de sal (M I e II) foram as mais ativas, com valores de atividade da ordem de 27,40 e 72,66 UI mg-1, respectivamente, em relação à HEP. Portanto, a secagem por liofilização seria uma forma mais eficaz na obtenção de PSs com atividade anticoagulante de Halymenia sp.

effect of macromolecule source and type of media during in vitro maturation of sheep oocytes on subsequent embryo development

Oocyte maturation and subsequent in vitro production [IVP] of embryos are affected by diverse groups of chemicals in maturation medium which are needed for successful mammalian oocyte maturation during which the dramatic cytoplasmic and nuclear reprogramming events take place. This study was designed to evaluate the effects of protein source [fetal bovine serum, FBS, and bovine serum albumin, BSA] as well as two different maturation media during in vitro maturation of ovine oocytes on subsequent embryo development. Cumulus oocyte complexes were recovered from ovaries obtained from slaughter house and cultured for 24 hr in either TCM-199 or SOFaa maturation medium supplemented with 10% [v/v] FBS or 0.8% [w/v] BSA. Data were analyzed by one-way ANOVA using Sigma Stat [Ver. 2]. A p-value smaller than 0.05 was considered statistically significant. The proportions of cleavage and total blastocyst [evaluated on days 3 and 6, respectively] were significantly higher in FBS than BSA supplemented groups, though no differences were observed between the two used different maturation media. The cryotolerance of blastocysts was negatively influenced by the presence of FBS rather than BSA during IVM. The quality of produced embryos, however, was affected neither by the source of macromolecules nor the maturation medium in terms of hatching rate, total blastocyst cells and inner cell mass/total cell ratio. The rate of oocyte development was improved by the presence of FBS, though the cryosurvival of resulting blastocysts was negatively influenced by the presence of the serum during in vitro production of sheep oocytes

M cell in vitro model and its application in oral delivery of macromolecular drugs / 药学学报

The oral administration of bioactive macromolecular drugs such as proteins, peptides and nucleic acids represents unprecedented challenges from the drug delivery point of view. One key consideration is how to overcome the gastrointestinal tract absorption barrier. Recent studies suggest that microfold cell (M cell), a kind of specialized antigen-sampling epithelial cell which is characterized by a high endocytic rate and low degradation ability, may play an important role in macromolecule oral absorption. The development of an in vitro M cell coculture system and its modified models greatly advanced the study of M cells and the development of oral delivery system for macromolecular drugs. The special structure, function and formation characteristics, and biomarkers of M cell are summarized in this review. The applications of in vitro M cell models in developing oral delivery system ofbioactive macromolecular drugs are discussed.

Acute phase reaction of different macromolecule vascular grafts healing in rat muscle / 生物工程学报

To find out which biomaterial had the best biocompatibility, we compared the acute phase reaction of common biomaterials preparing for vascular grafts with the material of polyurethane modified by silk fibroin (SF-PU(1:1)). After transplanted the materials of dacron, polyterafluoroethylene (e-PTFE), polyurethane (PU), SF-PU(1:1) in rat muscle for one week, we studied the influence of different biomaterials on the histocompatibility by using rat acute toxicity test, test of local reaction in muscle, tissue section staining, WBC and PLT count. As a result, dacron had the worst histocompatibility. The other biomaterials had slight local inflammatory reaction. The WBC and PLT was nearly the same with the blank except dacron. e-PTFE, pure PU and SF-PU(1:1) had the better histocompatibility than traditional dacron. Especially SF-PU(1:1) had the best histocompatibility. Because of the better physical properties and histocompatibility of SF-PU( 1:1), the prospect of preparing small-diameter vascular grafts with SF-PU was cheerful.

Therapeutic effect of ossicular reconstruction with bioceramic or porous macromolecular polyethylene partial ossicular replacement prosthesis in patients with tympanosclerosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of ossicular reconstruction with partial ossicular replacement prosthesis (PORP) in patients with tympanosclerosis.</p><p><b>METHODS</b>The data of 31 cases of tympanosclerosis treated between 1992 and 2009 were reviewed. Of the 31 patients, 17 (17 ears) underwent ossicular reconstruction with porous macromolecular polyethylene PORP, and 14 (14 ears) with bioceramic PORP. All the patients were followed up for 3-24 months.</p><p><b>RESULTS</b>Significant improvement was found in postoperative speech frequency (500, 1000, 2000 Hz) pure tone average (PTA) and air-bone gap (ABG) (P < 0.05) after the treatments without statistically significant differences between the two groups (P > 0.05).</p><p><b>CONCLUSION</b>Porous macromolecular polyethylene and bioceramic are valuable ossicular prosthesis for tympanosclerosis.</p>

Modeling of diffusion transport through oral biofilms with the inverse problem method / 国际口腔科学杂志·英文版

<p><b>AIM</b>The purpose of this study was to develop a mathematical model to quantitatively describe the passive transport of macromolecules within dental biofilms.</p><p><b>METHODOLOGY</b>Fluorescently labeled dextrans with different molecular mass (3 kD, 10 kD, 40 kD, 70 kD, 2000 kD) were used as a series of diffusion probes. Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum were used as inocula for biofilm formation. The diffusion processes of different probes through the in vitro biofilm were recorded with a confocal laser microscope.</p><p><b>RESULTS</b>Mathematical function of biofilm penetration was constructed on the basis of the inverse problem method. Based on this function, not only the relationship between average concentration of steady-state and molecule weights can be analyzed, but also that between penetrative time and molecule weights.</p><p><b>CONCLUSION</b>This can be used to predict the effective concentration and the penetrative time of anti-biofilm medicines that can diffuse through oral biofilm. Furthermore, an improved model for large molecule is proposed by considering the exchange time at the upper boundary of the dental biofilm.</p>

A review of automatic particle recognition in Cryo-EM images / 生物医学工程学杂志

Advances in cryo-electron microscopy (Cryo-EM) and single-particle reconstruction have led to increasingly high resolutions of macromolecular three-dimensional reconstruction. However, for keeping up the continuing improvements in resolution, it is necessary to increase the number of particles included in performing reconstructions. Manual selection of particles, even assisted by computer, is a bottleneck of single-particle reconstruction. Cryo-EM image has low signal-to-noise ratio and low contrast, which leads to difficulty in particle picking. Various approaches have been developed to address the problem of automatic particle. This paper describes the application of template-based method, edge based method, feature-based method, neural network, DoG-based and simulated annealing approach in particle picking. The characteristics of various approaches are discussed, and the future development is presented.

Progress in researches on synthetic antimicrobial macromolecular polymers / 生物医学工程学杂志

Broad-spectrum antimicrobial peptides provide a new way to address the urgent growing problem of bacterial resistance. However, the limited natural resources and the high cost of extraction and purification of natural antimicrobial peptides can not meet the requirements of clinical application. In order to solve this problem, researchers have utilized two basic common structural features (amphiphilic and cationic) for designing and preparing synthetic antimicrobial macromolecular polymers. During the last decade, several kinds of amphiphilic polymers, including arylamide oligomers, phenylene ethynylenes, polymethacrylates, polynorbornenes as well as nylon-3 polymers have been synthesized. In this paper, the structures, antibacterial activities and selectivities of these polymers are reviewed, and the effects of molecular size, polarity and ratio of hydrophobic groups, positive charge density on antibacterial activity and selectivity are also summarized.

Progress on antineoplastic constituents derived from polypore fungi / 中国中药杂志

Polypore fungi is a cluster of important pharmacological fungi with significant antitumor activity. In recent years, the antineoplastic constituents from polypore fungi have been comprehensively studied. Through investigating the domestic and overseas studied paper, the antitumor active constituents derived from polypore fungi including high molecular weight compounds such as polysaccharides, glycopeptides, glycoproteins, lectins, and lipid soluble low molecular weight compounds such as terpenoids, steroids, phenolics, benzopyranones, were reviewed. In addition, the significance in the exploitation of new drug for antitumor by the application of polypore fungi was discussed at the end of this paper.

Evaluation of AB-8 macroporous adsorption resin for adsorption of total flavones in liquorice / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the performance of AB-8 macroporous adsorption resin for adsorption and desorption of flavones in liquorice.</p><p><b>METHODS</b>The concentration of flavones in liquorice was determined by ultraviolet spectrophotometry, and the adsorption behavior of AB-8 macroporous adsorption resin to flavones in liquorice was examined for the adsorption capacity and the volume of solution loaded.</p><p><b>RESULTS</b>Optimal adsorption of flavones was achieved with the sample pH of 5, total flavones concentration in the solution of 0.85 mg/ml, sample flow velocity of 3 BV/h, and washing with 60% ethanol at the flow velocity of 3 BV/h.</p><p><b>CONCLUSION</b>AB-8 macroporous adsorption resin can be well applicable for enrichment of flavones in liquorice.</p>