Barcode-style lateral flow immunochromatographic strip for the semi-quantitative detection of ochratoxin A in coffee samples.

Ochratoxin A (OTA) is a mycotoxin contaminating agricultural products produced by fungi, associated with important toxic effects. Thus, the development of fast, sensitive, and economical approaches for OTA detection is crucial. In this study, a barcode-style lateral flow assay for the semi-quantitative detection of OTA in coffee samples was developed. To achieve this goal, a BSA-OTA complex was immobilized in three test zones to compete with OTA molecules in the sample for binding with anti-OTA antibodies labeled with gold nanoparticles. Different concentrations of OTA in the sample produced distinct colour patterns, allowing semi-quantification of the analyte. The assay exhibited high sensitivity, with a limit of detection of 2.5 µg.L-1, and high reproducibility, with variation coefficient values between 2% and 13%. Moreover, the colour patterns obtained in the analysis with coffee samples were similar to the results obtained with standard OTA solutions, demonstrating a reliable applicability in real samples.

Localized Surface Plasmon Resonance-Based Nanosensor for Rapid Detection of Glyphosate in Food Samples.

In this study, we developed a biosensor based on the localized surface plasmon resonance (LSPR) phenomenon of gold nanoparticles (AuNPs) to detect the widely used herbicide glyphosate in food samples. To do so, either cysteamine or a specific antibody for glyphosate were conjugated to the surface of the nanoparticles. AuNPs were synthesized using the sodium citrate reduction method and had their concentration determined via inductively plasma coupled mass spectrometry. Their optical properties were analyzed using UV-vis spectroscopy, X-ray diffraction, and transmission electron microscopy. Functionalized AuNPs were further characterized via Fourier-transform infrared spectroscopy, Raman scattering, Zeta potential, and dynamic light scattering. Both conjugates succeeded in detecting the presence of glyphosate in the colloid, although nanoparticles functionalized with cysteamine tended to aggregate at high concentrations of the herbicide. On the other hand, AuNPs functionalized with anti-glyphosate functioned at a broad concentration range and successfully identified the presence of the herbicide in non-organic coffee samples and when it was added to an organic coffee sample. This study demonstrates the potential of AuNP-based biosensors to detect glyphosate in food samples. The low-cost and specificity of these biosensors make them a viable alternative to current methods for detecting glyphosate in foodstuffs.

Liposomal stem cell extract formulation from Coffea canephora shows outstanding anti-inflammatory activity, increased tissue repair, neocollagenesis and neoangiogenesis.

Coffea canephora plant stem cells can have bioactive compounds with tissue repairing and anti-inflammatory action. This study aimed to develop a liposomal stem cell extract formulation obtained from the leaves of C. canephora (LSCECC) and to investigate its capacity to contribute to the dynamic mechanisms of tissue repair. The liposome cream was developed and characterized through the dynamic light scattering technique, atomic force microscopy, and transmission electron microscopy. The excisional full-thickness skin wound model was used and daily topically treated with the LSCECC formulation or vehicle control. On days 2, 7, 14, and 21 after wounding, five rats from each group were euthanized and the rates of wound closure and re-epithelialization were evaluated using biochemical and histological tests. LSCECC resulted in faster re-epithelialization exhibiting a significant reduction in wound area of 36.4, 42.4, and 87.5% after 7, 10, and 14 days, respectively, when compared to vehicle control. LSCECC treated wounds exhibited an increase in granular tissue and a proper inflammatory response mediated by the reduction of pro-inflammatory cytokines like TNF-α and IL-6 and an increase of IL-10. Furthermore, wounds treated with LSCECC showed an increase in the deposition and organization of collagen fibers at the wound site and improved scar tissue quality due to the increase in transforming growth factor-beta and vascular endothelial growth factor. Our data showed that LSCECC improves wound healing, the formation of extracellular matrix, modulates inflammatory response, and promotes neovascularization being consider a promising bioactive extract to promote and support healthy skin. The graphical presents the action of LSCECC in all four phases of wound healing and tissue repair. The LSCECC can reduce the inflammatory infiltrate in the inflammatory phase by decreasing the pro-inflammatory cytokines like IL-6 and TNF-α, in addition to maintaining this modulation through lesser activation and recruitment of macrophages. The LSCECC can also increase the release of IL-10, an anti-inflammatory cytokine, decreasing local edema. The increase in VEGF provides neovascularization and the supply of nutrients to newly repaired tissue. Finally, signaling via TGF-ß increases the production and organization of collagen fibers in the remodeling phase.

Interaction effects between macromolecules and photosensitizer on the ability of AlPc and InPc-loaded PHB magnetic nanoparticles in photooxidatizing simple biomolecules.

The parameters used in the preparation of polymeric nanoparticles can influence its ability to photooxidate biomolecules. This work evaluated the effects of four parameter to prepare Poly(3-hydroxybutyrate) (PHB) nanoparticle loaded with aluminum and indium phthalocyanine (AlPc and InPc), together with iron oxide nanoparticles, assessing their influence on the size, the entrapment efficiency, and the nanoparticles recovery efficacy. The capability of free, and encapsulated, AlPc and InPc in photooxidating the bovine serum albumin (BSA) and tryptophan (Trp) was monitored by fluorescence. The AlPc-loaded nanoparticles had a larger size and a greater entrapment efficiency than that obtained by InPc-loaded nanoparticles. The free InPc was more efficient than the free AlPc to photooxidize the BSA and Trp; whereas the encapsulated AlPc was more efficient than encapsulated InPc to photooxidize the biomolecules. The higher hydrophobicity of the AlPc, combined with the greater aggregation state and the major interaction with the BSA, quenching the capacity of the free AlPc to photooxidate the biomolecules; whereas the greater interaction of the AlPc with PHB reduce the aggregation effect on the free molecules in the aqueous phase and increase the entrapment efficiency, resulting in an improving of the photodynamic efficiency and an increase of the photooxidation rate constant.

Impact of immobilization strategies on the activity and recyclability of lipases in nanomagnetic supports.

The use of enzymes immobilized on nanomagnetic supports has produced surprising results in catalysis, mainly due to the increase in surface area and the potential for recovery and reuse. However, the meticulous control of the process and difficulties in reproducibility have made industrial-scale applications unfeasible. Furthermore, the role of conjugation strategies in the catalytic activity and recycling of catalysts is unclear. Therefore, the objective of this study was to compare the conjugation of enzymes on nanomagnetic supports through physical adsorption (naked) or covalent bonding with mercaptopropyltrimethoxysilane (MPTS) and aminopropyltriethoxysilane (APTS) ligands. The free lipase obtained from Rhizomucor miehei was used as a model enzyme. Total protein and enzyme activity were determined using spectrophotometry (UV-Vis) and the p-nitrophenyl palmitate (p-NPP) hydrolysis method. The results indicated that a more significant enzyme surface loading does not always mean better immobilization success. The physical adsorption binding strategy had higher surface loading and low catalytic activity. On the other hand, covalent coupling with free NH2 had an excellent catalytic activity with very low surface loading. Finally, we show that recyclability can be improved with conjugation mediated by disulfide bonds. The findings presented here are essential for developing nanoconjugates with high enzymatic activity, which can guarantee the success of several industrial applications.

Epigallocatechin gallate has antibacterial and antibiofilm activity in methicillin resistant and susceptible Staphylococcus aureus of different lineages in non-cytotoxic concentrations.

Staphylococcus aureus is an opportunistic agent that can cause a variety of infections, both hospital and community-acquired. Epigallocatechin gallate (EGCG), a flavonoid present in the leaves of Camellia sinensis, has different biological activities, including antimicrobial potential. Here we evaluate the antibacterial and antibiofilm potential of EGCG in nine clinical strains of S. aureus with different genetic profile and antimicrobial susceptibilities. The minimum inhibitory concentrations (MIC) of EGCG ranged from 7.81 to 62.5 µg/mL, and bactericidal activity was observed at 4 times the MIC. Sub-inhibitory concentrations were able to inhibit biofilm production. Concentrations ≤62.5 µg/mL of EGCG were non-cytotoxic for murine macrophages. EGCG significantly reduced the mortality of infected Galleria mellonella larvae with the S. aureus, having shown relevant antibiofilm properties and efficacy in inhibiting the growth of different clinical isolates of S. aureus, thus being a promising substance for the treatment of infections caused by this agent.

Rapid and sensitive detection of ochratoxin A using antibody-conjugated gold nanoparticles based on Localized Surface Plasmon Resonance.

The regulation of tolerable levels of ochratoxin A in food for human and animal consumption has been defined in some countries. To meet these levels, simpler, more efficient, and faster analytical methods are being developed to facilitate the identification of this dangerous contaminant in food. Here, we combined gold nanoparticles (AuNPs) with anti-ochratoxin A (OTA) IgG to detect elementary levels of OTA based on Localized Surface Plasmon Resonance. AuNPs were prepared with trisodium citrate and characterized by UV-visible spectroscopy, X-ray, dynamic light scattering, and transmission electron microscopy. The conjugation of AuNPs to IgG anti-OTA was confirmed by bathochromic shift (UV-vis) and RAMAN spectroscopy. The sensitivity of the nanosensor was investigated by measuring LSPR band λmax shifts. Our results suggest this assay is highly sensitive, with a lower detection limit of about 0.001 pg mL-1. The LSPR nanosensor reduced detection limits by roughly 10 times compared to other methods. We demonstrated that the approach investigated here is a rapid and sensitive method for OTA detection.

Controlled biosynthesis of gold nanoparticles with Coffea arabica using factorial design.

Green synthesis of metallic nanoparticles has become incredibly popular, mainly by minimizing problems of environmental contamination and by being able to reduce, stabilize and potentially functionalize nanomaterials. Such compounds have possible applications in various areas, e.g., pharmaceuticals (drug delivery systems, cosmetics), textile industry (clothing with antimicrobial properties), diagnostic medicine (imaging, high efficiency biosensors), energy (solar panels), bioremediation, among others. However, the lack of reproducibility and information on the control mechanisms during synthesis have made the application of green-synthesized nanoparticles unfeasible. Thus, this study proposed the investigation of the main mechanisms affecting synthesis control, using factorial design for the preparation of gold nanoparticles with extract of Coffea arabica. We obtained stable (Zeta Potential, UV-vis and DLS), monodisperse, and quasi-spherical (TEM) nanoparticles, which presented adsorbed aromatic molecules (FTIR and RAMAN) and defined crystal structure (XRD), proving that the plant extract acted as a reducing agent, as well as a stabilizer and functionalizer for the synthesized nanostructures. The factorial design employed here to obtain gold nanoparticles with Coffea arabica extract allowed for a controlled and reproducible synthesis, enabling new possibilities for the application in several fields.

Impact of conjugation strategies for targeting of antibodies in gold nanoparticles for ultrasensitive detection of 17ß-estradiol.

Antibody-coated nanoparticles have recently attracted considerable attention, with the focus falling on diagnostics. Nevertheless, controlled antibody bioconjugation remains a challenge. Here, we present two strategies of bioconjugation with the aim of evaluating the best approach for the coupling of antibodies on the surface of nanomaterials in an oriented way. We employed electrostatic interaction (physical adsorption) and covalent conjugation in the orientation of antibodies on the metallic surface as coupling methods, and their influence on the detection of 17ß-estradiol was addressed with localized surface plasmon resonance. The understanding of these mechanisms is fundamental for the development of reproducible inorganic bioconjugates with oriented surface as well sensibility of immunoassays.

PLGA-PEG nanoparticles containing gallium phthalocyanine: Preparation, optimization and analysis of its photodynamic efficiency on red blood cell and Hepa-1C1C7.

Poly(lactide-co-glycolide) (PLGA) has been used for the encapsulation of phthalocyanine motived by its biocompatibility and biodegradability. Many studies have already been done to evaluate the influence of parameters used in the PLGA nanoparticle synthesis but without the evaluation of the combinatory interaction between these parameters on the nanoparticulate properties. Ga(III)-phthalocyanine (GaPc) was encapsulated into the PEGlated PLGA-nanoparticles and the individual and combinatory effects of the emulsification time, the method used for the nanoparticle synthesis and the temperature of the aqueous phase was evaluated on the size, entrapment efficiency, efficacy of nanoparticle recovery, residual PVA and zeta potential value using a 23 factorial design (FD). Mathematical models were adjustable to the data and evolutionary operations were performed to optimize the nanoparticle size. The ability of the optimized nanoparticle to decrease the viability of the Hepa-1C1C7 cell and the blood red cell was also evaluated. The FD disclosed the emulsification-diffusion method decreased the residual PVA and the size of PLGA-PEG nanoparticle, but also decreased the entrapment efficiency of GaPc, the zeta potential absolute value and the recovery efficacy of nanoparticles. The combinatory effect between the method used in the nanoparticle preparation and the temperature of aqueous phase influenced four of the five evaluated properties. The viability of Hepa-1C1C7 cells was reduced until 13× when the cells were irradiated in the presence of encapsulated GaPc while it was decreased until 4.7× when the experiment was carried out with the free GaPc. The encapsulated GaPc was also more efficient to cause the haemolysis of the RBC than it was the free GaPc. The optimization of the nanoparticles synthesis increased the efficiency of the GaPc to oxidize the evaluated cells.

Antibacterial Activity of Terpenes and Terpenoids Present in Essential Oils.

Background: The antimicrobial activity of essential oils has been reported in hundreds of studies, however, the great majority of these studies attribute the activity to the most prevalent compounds without analyzing them independently. Therefore, the aim was to investigate the antibacterial activity of 33 free terpenes commonly found in essential oils and evaluate the cellular ultrastructure to verify possible damage to the cellular membrane. Methods: Screening was performed to select substances with possible antimicrobial activity, then the minimal inhibitory concentrations, bactericidal activity and 24-h time-kill curve studies were evaluated by standard protocols. In addition, the ultrastructure of control and death bacteria were evaluated by scanning electron microscopy. Results: Only 16 of the 33 compounds had antimicrobial activity at the initial screening. Eugenol exhibited rapid bactericidal action against Salmonella enterica serovar Typhimurium (2 h). Terpineol showed excellent bactericidal activity against S. aureus strains. Carveol, citronellol and geraniol presented a rapid bactericidal effect against E. coli. Conclusions: The higher antimicrobial activity was related to the presence of hydroxyl groups (phenolic and alcohol compounds), whereas hydrocarbons resulted in less activity. The first group, such as carvacrol, l-carveol, eugenol, trans-geraniol, and thymol, showed higher activity when compared to sulfanilamide. Images obtained by scanning electron microscopy indicate that the mechanism causing the cell death of the evaluated bacteria is based on the loss of cellular membrane integrity of function. The present study brings detailed knowledge about the antimicrobial activity of the individual compounds present in essential oils, that can provide a greater understanding for the future researches.

Antioxidant, antimicrobial and cytotoxic activities of gold nanoparticles capped with quercetin.

In the present work, we report the antioxidant, antimicrobial and cytotoxic activities of quercetin-capped gold nanoparticles (AuNPsQct). The synthesis of AuNPsQct was confirmed by UV-Vis spectroscopy, FTIR and transmission electron microscopy (TEM) analyses. The FTIR spectrum showed the integrity of the quercetin molecules on the nanoparticle surface. The TEM images showed sizes less than 100 nm and a slight spherical shape. The electrostatic stability was confirmed by the zeta potential method. The antioxidant activity of quercetin, evaluated by DPPH, ABTS and nitric oxide free radical scavenging methods, was preserved in the gold nanoparticles, furthermore quercetin-capped gold nanoparticles (IR50 0.37 µg/mL) demonstrated a higher antioxidant activity than free quercetin (IR50 0.57 µg/mL) by nitric oxide free radical scavenging method. Strong antifungal activity was observed for Aspergillus fumigatus with concentrations ranging from 0.1 to 0.5 mg/mL. The nanoparticles with quercetin did not exhibit cytotoxicity to human fibroblasts (L929 cells). In conclusion, these results suggest that AuNPsQct, produced by cost-effective method, can act as a promising candidate for different medical applications.

Maltodextrin and Gum Arabic-Based Microencapsulation Methods for Anthocyanin Preservation in Juçara Palm (Euterpe edulis Martius) Fruit Pulp.

The juçara fruits (Euterpe edulis Martius), native to the Atlantic Forest, are rich in anthocyanins. To preserve the anthocyanins in juçara fruit pulp, this study aimed to evaluate the effectiveness of microencapsulation by spray drying and freeze drying with maltodextrin (dextrose equivalent 16.5 to 19.5) and gum arabic in different proportions. The obtained microparticles were characterized by quantifying the total polyphenol and anthocyanin contents, by performing differential scanning calorimetry, thermogravimetry, and infrared spectroscopy and by using scanning electron microscopy to analyze the morphology of the particles. The total amount of polyphenols in the fruit pulp was 750 ± 16.7 mg GAE/100 g of the freeze-dried sample. The total anthocyanins in the fruit pulp was 181.25 ± 5.36 (mg/100 g). The microparticles were formed by employing maltodextrin and gum arabic in a 1:1 proportion as the polymeric matrix; the mixtures of pulp and polymeric matrix were prepared in proportions of 2:3 and 2:1, preserving up to 83.69% of the anthocyanin content. Lyophilization of the 2:1 mixture resulted in an anthocyanin content of 116.89 ± 4.43 (mg/100 g), whereas lyophilization of the 2:3 mixture resulted in 151.68 ± 1.39 (mg/100 g) anthocyanin content, which did not differ from the value obtained by spray drying the 2:3 mixture (150.76 ± 5.79 (mg/100 g)). Thermal analyses showed that the microparticles obtained by freeze drying at a ratio of 2:3 presented greater resistance to degradation with increasing temperature. The incorporation of the pulp in the polymeric matrix was demonstrated by IR analyses. Microparticles obtained by freeze drying showed the formation of various-sized flakes, whereas those obtained by spray drying were spherical in shape. Microencapsulation is a possible alternative for improving the stability of the anthocyanins in this fruit.

Extracellular biosynthesis of silver nanoparticles using the cell-free filtrate of nematophagous fungus Duddingtonia flagrans.

The biosynthesis of metallic nanoparticles (NPs) using biological systems such as fungi has evolved to become an important area of nanobiotechnology. Herein, we report for the first time the extracellular synthesis of highly stable silver NPs (AgNPs) using the nematophagous fungus Duddingtonia flagrans (AC001). The fungal cell-free filtrate was analyzed by the Bradford method and 3,5-dinitrosalicylic acid assay and used to synthesize the AgNPs in the presence of a 1 mM AgNO3 solution. They have been characterized by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy, dynamic light scattering, Zeta potential measurements, Fourier-transform infrared, and Raman spectroscopes. UV-Vis spectroscopy confirmed bioreduction, while X-ray diffractometry established the crystalline nature of the AgNPs. Dynamic light scattering and transmission electron microscopy images showed approximately 11, 38 nm monodisperse and quasispherical AgNPs. Zeta potential analysis was able to show a considerable stability of AgNPs. The N-H stretches in Fourier-transform infrared spectroscopy indicate the presence of protein molecules. The Raman bands suggest that chitinase was involved in the growth and stabilization of AgNPs, through the coating of the particles. Our results show that the NPs we synthesized have good stability, high yield, and monodispersion.

Virtual Reconstruction and Three-Dimensional Printing of Blood Cells as a Tool in Cell Biology Education.

The cell biology discipline constitutes a highly dynamic field whose concepts take a long time to be incorporated into the educational system, especially in developing countries. Amongst the main obstacles to the introduction of new cell biology concepts to students is their general lack of identification with most teaching methods. The introduction of elaborated figures, movies and animations to textbooks has given a tremendous contribution to the learning process and the search for novel teaching methods has been a central goal in cell biology education. Some specialized tools, however, are usually only available in advanced research centers or in institutions that are traditionally involved with the development of novel teaching/learning processes, and are far from becoming reality in the majority of life sciences schools. When combined with the known declining interest in science among young people, a critical scenario may result. This is especially important in the field of electron microscopy and associated techniques, methods that have greatly contributed to the current knowledge on the structure and function of different cell biology models but are rarely made accessible to most students. In this work, we propose a strategy to increase the engagement of students into the world of cell and structural biology by combining 3D electron microscopy techniques and 3D prototyping technology (3D printing) to generate 3D physical models that accurately and realistically reproduce a close-to-the native structure of the cell and serve as a tool for students and teachers outside the main centers. We introduce three strategies for 3D imaging, modeling and prototyping of cells and propose the establishment of a virtual platform where different digital models can be deposited by EM groups and subsequently downloaded and printed in different schools, universities, research centers and museums, thereby modernizing teaching of cell biology and increasing the accessibility to modern approaches in basic science.

Effects of captopril on cardiovascular reflexes and respiratory mechanisms in rats submitted to monocrotaline-induced pulmonary arterial hypertension.

BACKGROUND: Pulmonary Arterial Hypertension (PAH) is a disease associated with increased arteriolar resistance in the lungs. Due to hypoxemia, some physiological mechanisms can be posteriorly affected, including respiratory and cardiovascular reflexes, but this has not yet been fully investigated. This study aimed to evaluate how these mechanisms were affected by monocrotaline (MCT)-induced PAH and the possible therapeutic role of angiotensin converting enzyme inhibitor (ACEi), captopril, in reversing this remodeling process. METHODS AND RESULTS: Groups of Wistar rats received MCT injections (60 mg kg(-1)). Three weeks later, they received captopril (CPT, 100 mg kg(-1)) in their drinking water (MCT + CPT) or water alone (MCT) for 2 weeks. As control, saline-treated animals received captopril in their drinking water (CPT) or water alone (CON), also for 2 weeks. Results showed that PAH was fully induced in the MCT group, evidenced by a high pulmonary index. Gasometrical and respiratory analyses showed hypoxemia and compensatory hyperventilation. CPT treatment brought these parameters to similar values to those observed in the CON group. We observed that autonomic dysfunction in the MCT group was suppressed by CPT. Finally, cardiovascular reflexes analysis showed increased chemoreflex responses in the MCT group, while baroreflex sensibility was decreased. Surprisingly, CPT normalized these reflex responses to values similar to the CON group. CONCLUSIONS: The present study demonstrates that MCT-induced PAH induces compensatory respiratory responses, dysautonomia, and baroreflex dysfunction and increases chemoreflex responses. The data also indicate that CPT was effective in reversing these cardio-respiratory disorders, suggesting that ACEi could be a potential therapeutic target for PAH.

Macrophages from chickens selected for high antibody response produced more nitric oxide and have greater phagocytic capacity.

Macrophages are fundamental cells of the innate immune system, which, through phagocytosis and nitric oxide production, eliminate pathogens. The aim of the present study was to determine if macrophages from chicken families divergently selected to high and low antibodies response differ in nitric oxide production and phagocytic capacity. Blood monocytes derived macrophages were activated with lipopolysaccharide and supernatant from chicken spleen lymphocytes cultured with Concanavalin A (containing chicken interferon). Nitric oxide production was evaluated in culture supernatants. Phagocytic capacity of activated and non-activated macrophages was assayed using yeasts and IgY opsonized sheep red blood cells. Activated and non-activated macrophages from the high antibodies response family produced higher nitric oxide levels, internalized more yeast and significantly more opsonized sheep red blood cells than macrophages from the low antibodies response family. Moreover, activated macrophages became more elongated and widely spread. These findings indicate that macrophages from the high antibodies response family were more active suggesting that the differences in antibody response also depend on macrophage function.

Evaluation of PvuII and XbaI polymorphisms in the estrogen receptor alpha gene (ESR1) in relation to menstrual cycle timing and reproductive parameters in post-menopausal women.

OBJECTIVE: To evaluate the association of -397T>C and -351A>G single nucleotide polymorphisms (SNPs) - also called PvuII and XbaI, respectively - located on estrogen receptor alpha (ERS1) gene with age at menarche, menopause onset, fertility and miscarriage in a population of post-menopausal women. STUDY DESIGN: Cross-sectional study with 273 healthy, high miscegenated, post-menopausal women (mean age of 63.1±9.7 years old). Subjects were genotyped for PvuII and XbaI SNPs by PCR-RFLP and confirmed by automatic sequencing. Reproduction informations (age at menarche, age at menopause, number of pregnancies, fertility rate and miscarriages) were obtained by retrospective study using a questionnaire. RESULT(S): Age at menarche, menopause onset, number of pregnancies, total fertility rate, and parity did not seem to be influenced by any of the studied genotypes (chi-square, p>0.05). However, women carrying the xx genotype showed a 44% higher chance of miscarriage, whereas this value did not trespass 16% for any other genotype analyzed. It has been also observed a higher occurrence of miscarriage in association with combined xxpp genotype of ERS1 gene (chi-square, p<0.01). CONCLUSION(S): The present data indicate that the studied SNPs on ERS1 gene do not influence the menstrual cycle timing and parity but there is a strong relationship between the xx ERS1 SNP genotype and the incidence of miscarriage in the post-menopausal population analyzed.

Regulatory T cell as a target for cancer therapy.

Advances in our understanding of CD4(+)CD25(+)Foxp3(+) regulatory T cells (T(Regs)) enabled the characterization of their activities in maintaining peripheral tolerance, preventing autoimmune diseases, and limiting chronic inflammatory diseases. Ironically, an effective action of these cells during tumor development can limit beneficial responses by suppressing immunity and limiting antitumor resistance, whereas one of the main functions of the immune system is to eliminate malignant cells. During the last years, the immunological role, mechanism of action, and clinical importance of these cells were profoundly characterized and the relationship between this subset of lymphocytes and cancerous cells arises as a key factor that influences tumor development. Recent insights obtained from clinical studies and experimental mouse models expand our perception of the potential role of T(Regs) in cancer treatment. In this review we describe the basic mechanisms of T(Reg) origin and differentiation, their potential role in cancer, as well as the future perspectives concerning the modulation of these cells as a potential approach for anticancer strategies.

Growth inhibition of Staphylococcus aureus by chicken egg yolk antibodies.

INTRODUCTION: The aim was to evaluate the ability of egg yolk antibody (IgY) in blocking Staphylococcus aureus growth in vitro. MATERIALS AND METHODS: Specific IgY was produced by immunizing hens with formalin-killed S. aureus (ATCC 33593). Specific IgY against S. aureus was obtained from the yolks of their eggs with a carrageenan solution. IgY was identified by SDS-PAGE and Western blot and its activity against S. aureus was tested by ELISA. A growth inhibition assay and protein concentration determination were also conducted. RESULTS: ELISA indicated that the IgY was specific to the antigen; this activity was confirmed by Western blotting. The growth of S. aureus was inhibited by the specific IgY at concentrations of 1-5 microg/ml The bacteriostatic function of IgY appeared to result possibly from the interaction of IgY with surface components of S. aureus. In vitro experiments showed that the immunoglobulin from egg yolk interfered with the culture growth of the S. aureus. CONCLUSION: These findings indicate that eggs from hens immunized with appropriate antigens are a potentially useful source of passive immunity.