Physical Attractiveness as a Signal of Biological Quality

It has been commonly thought that standards of beauty are arbitrary cultural conventions that vary between cultures and time. In my thesis I found that it is not so. Instead, I show that attractiveness and preferred traits serve as cues to phenotypic qualities that provide selective benefits for those who choose their mates based on these criteria. In the first study I show that attractive men have a stronger antibody response to the hepatitis b vaccine and higher levels of testosterone than their less attractive peers. Men with low levels of testosterone also tend to have high levels of the stress hormone cortisol, suggesting that their immune responses may have been inhibited by stress hormones. Thus, facial attractiveness may serve as an honest cue of the strength of immune defence in men. In the second study, I show that the attractiveness of the male body is also a cue of better immunity. In addition, I show that adiposity, both in men’s faces and bodies, is a better cue of the strength of immunity and attractiveness than of masculinity. In the third study, I test the preferences of women from 13 countries for facial cues of testosterone and cortisol. I show that there is cross-cultural variation in women’s preference for cues of testosterone and cortisol in male faces. I found a relationship between the health of a nation and women’s preferences for cues of testosterone in the male face and the interaction between preferences for cues of testosterone and cortisol. I show also a relationship between preferences for cues of testosterone and a societal-level measure of parasite stress. Thus, it seems that societal-level ecological factors influence the relative value of traits as revealed by combinations of testosterone and stress hormones. In the fourth study, I show that women’s immune responsiveness (amount of antibodies produced) does not predict facial attractiveness. Instead, plasma cortisol level is negatively associated with attractiveness, indicating that stressed women look less attractive. Fat percentage is curvilinearly associated with facial attractiveness, indicating that being too thin or too fat reduces attractiveness. This study suggests that in contrast to men, facial attractiveness in women does not indicate the strength of immune defence, but is associated with other aspects of long-term health and fertility: circulating levels of the stress hormone cortisol and the percentage of body fat. In the last study I show that the attractiveness of men’s body odor is positively correlated with stress hormone levels, suggesting also that the attractiveness of body odors may signal the phenotypic quality of males to females. However, the attractiveness of men’s body odor was not associated with testosterone levels. My thesis suggests that the standard of beauty is not in the eye of the beholder. Instead, our standard of beauty is hardwired in our brains by genes that are selected by natural selection and also influenced by current environmental conditions.

Use of grass carp (Ctenopharyngodon idella) as a biological control agent for submerged aquatic macrophytes

This study aimed to evaluate feed preference and control efficacy of grass carp (Ctenopharyngodon idella) on the aquatic macrophytes Ceratophyllum demersum, Egeria densa and Egeria najas. An experiment was carried out at mesocosms conditions with 2,000 liters capacity and water residence time of 2.8 days. C. demersum, E. densa e E. najas biomasses were offered individually with sixty g and coupled in similar quantities of 30 g of each species, evaluated during 81 days, envolving 6 treatments. (1 - C. demersum, 2 - E. najas, 3 -E. densa, 4 - C. demersum + E. najas, 5 - C. demersum + E. densa and 6 - E. najas + E. densa). When offered individually, E. najas and C. demersum presented the same predation rate by grass carp, which was higher than E. densa predation rate. When plants were tested in pairs, the order of feed preference was C. demersum > E. najas > E. densa. E. najas and C. demersum percentage control ranged from 73 to 83%. No relation between biomass consumption and grass carp body weight gain was observed, probably due to differences in nutritional quality among macrophyte species according to fish necessities. Therefore, it is concluded that the use of grass carp is one excellent technique to control submersed macrophytes in Brazil.

Thermal-biological aspects on the seed germination of Cucumis anguria L.: influence of the seed coat

The seed coat influences the early stages of germination of many seeds and sometimes maintains seed dormancy. Early reports have shown that the testa influences the germination response of Cucumis anguria seeds to light although the response to temperature as influenced by the tegument is not well understood. The main purpose of this study was to observe the influence of the testa on the germination of Cucumis anguria by using parameters as germinability and isothermal germination rate. The assays were carried out in a thermal-gradient block with water imbibed seeds kept in darkness. Estimates of the activation enthalpies (deltaH) show |deltaH| < 50 kJ.mol-1 between 26.1 °C and 35.2 °C (intact seeds) and between 25.4 °C and 35.2 °C (scarified seeds), whereas at temperatures greater than 35.2 °C the germination may be limited by processes with |deltaH| > 125 kJ.mol-1. It is suggested that the testa limits embryo expansion rather than interfering with diffusion processes.

Influence of surface functionalization on the behavior of silica nanoparticles in biological systems

Personalized nanomedicine has been shown to provide advantages over traditional clinical imaging, diagnosis, and conventional medical treatment. Using nanoparticles can enhance and clarify the clinical targeting and imaging, and lead them exactly to the place in the body that is the goal of treatment. At the same time, one can reduce the side effects that usually occur in the parts of the body that are not targets for treatment. Nanoparticles are of a size that can penetrate into cells. Their surface functionalization offers a way to increase their sensitivity when detecting target molecules. In addition, it increases the potential for flexibility in particle design, their therapeutic function, and variation possibilities in diagnostics. Mesoporous nanoparticles of amorphous silica have attractive physical and chemical characteristics such as particle morphology, controllable pore size, and high surface area and pore volume. Additionally, the surface functionalization of silica nanoparticles is relatively straightforward, which enables optimization of the interaction between the particles and the biological system. The main goal of this study was to prepare traceable and targetable silica nanoparticles for medical applications with a special focus on particle dispersion stability, biocompatibility, and targeting capabilities. Nanoparticle properties are highly particle-size dependent and a good dispersion stability is a prerequisite for active therapeutic and diagnostic agents. In the study it was shown that traceable streptavidin-conjugated silica nanoparticles which exhibit a good dispersibility could be obtained by the suitable choice of a proper surface functionalization route. Theranostic nanoparticles should exhibit sufficient hydrolytic stability to effectively carry the medicine to the target cells after which they should disintegrate and dissolve. Furthermore, the surface groups should stay at the particle surface until the particle has been internalized by the cell in order to optimize cell specificity. Model particles with fluorescently-labeled regions were tested in vitro using light microscopy and image processing technology, which allowed a detailed study of the disintegration and dissolution process. The study showed that nanoparticles degrade more slowly outside, as compared to inside the cell. The main advantage of theranostic agents is their successful targeting in vitro and in vivo. Non-porous nanoparticles using monoclonal antibodies as guiding ligands were tested in vitro in order to follow their targeting ability and internalization. In addition to the targeting that was found successful, a specific internalization route for the particles could be detected. In the last part of the study, the objective was to clarify the feasibility of traceable mesoporous silica nanoparticles, loaded with a hydrophobic cancer drug, being applied for targeted drug delivery in vitro and in vivo. Particles were provided with a small molecular targeting ligand. In the study a significantly higher therapeutic effect could be achieved with nanoparticles compared to free drug. The nanoparticles were biocompatible and stayed in the tumor for a longer time than a free medicine did, before being eliminated by renal excretion. Overall, the results showed that mesoporous silica nanoparticles are biocompatible, biodegradable drug carriers and that cell specificity can be achieved both in vitro and in vivo.

Genetic control of characters associated with bean golden mosaic geminivirus resistance in Phaseolus vulgaris L.

Bean golden mosaic is the most important viral disease of the bean crop (Phaseolus vulgaris L.) in Latin America. The genetics of resistance to a Brazilian strain of bean golden mosaic virus (BGMV), was studied in a 4 x 4 diallel cross without reciprocals, among the parental genotypes DOR 303, EMGOPA 201 Ouro, Carnaval, and Redlands Greenleaf C. Seedlings of the four parents, six F1 hybrids, 12 backcrosses, and F2 generations for each combination were inoculated on the eighth day after sowing by exposure to a viruliferous whitefly (Bemisia tabaci Genn.) population for 24 h, in a glasshouse, prior to transplantation to field conditions. The full set of two parents, F1, F2 and respective backcrosses for each combination was considered to be a family. Data were recorded and analyzed for foliar yellowing, plant dwarfing, and pod malformation, using a randomized block design, with two replications. Weighted generation mean analysis was performed for each of the six families. An additive gene action model was significant for the three characteristics evaluated. On the other hand, non-additive gene action had greater absolute value in most cases. Resistance to foliar yellowing conferred by genes from DRO 303 was highly heritable and was expressed equally well in the different genetic backgrounds evaluated. Such resistance may be oligogenic. Broad- and narrow-sense heritabilities were relatively high for all response traits. The three traits studied were all positively correlated, indicating that they can be simultaneously selected for enhancement. The highest correlation coefficient was obtained for dwarfing x pod malformation.

Techniques of radioautography for medical and biological research

Standard techniques for radioautography used in biological and medical research can be classified into three categories, i.e., macroscopic radioautography, light microscopic radioautography and electron microscopic radioautography. The routine techniques used in these three procedures are described. With regard to macroscopic radioautography, whole body radioautography is a standard technique which employs freezing and cryosectioning and can demonstrate organ distributions of both soluble and insoluble compounds. In contrast, in light and electron microscopic radioautography, soluble and insoluble techniques are separated. In order to demonstrate insoluble labeled compounds, conventional chemical fixations such as formalin for light microscopy or buffered glutaraldehyde and osmium tetroxide for both light and electron microscopy followed by dehydration, embedding and wet-mounting applications of radioautographic emulsions can be used. For the demonstration of soluble labeled compounds, however, cryotechniques such as cryofixation, cryosectioning, freeze-drying, freeze-substitution followed by dry-sectioning and dry-mounting radioautography should be employed both for light and electron microscopy. The outlines of these techniques, which should be utilized in various fields of biological and medical research, are described in detail

Expression and biological activity of two recombinant polypeptides related to subunit 1 of the interferon-a receptor

Abnormal production of interferon alpha (IFN-a) has been found in certain autoimmune diseases and can be also observed after prolonged therapy with IFN-a. IFN-a can contribute to the pathogenesis of allograft rejection in bone marrow transplants. Therefore, the development of IFN-a inhibitors as a soluble receptor protein may be valuable for the therapeutic control of these diseases. We have expressed two polypeptides encoding amino acids 93-260 (P1) and 261-410 (P2) of the extracellular domain of subunit 1 of the interferon-a receptor (IFNAR 1-EC) in E. coli. The activities of the recombinant polypeptides and of their respective antibodies were evaluated using antiproliferative and antiviral assays. Expression of P1 and P2 polypeptides was achieved by transformation of cloned plasmid pRSET A into E. coli BL21(DE3)pLysS and by IPTG induction. P1 and P2 were purified by serial sonication steps and by gel filtration chromatography with 8 M urea and refolded by dialysis. Under reducing SDS-PAGE conditions, the molecular weight of P1 and P2 was 22 and 17 kDa, respectively. Polyclonal anti-P1 and anti-P2 antibodies were produced in mice. P1 and P2 and their respective polyclonal antibodies were able to block the antiproliferative activity of 6.25 nM IFN-aB on Daudi cells, but did not block IFN-aB activity at higher concentrations (>6.25 nM). On the other hand, the polypeptides and their respective antibodies did not inhibit the antiviral activity of IFN-aB on Hep 2/c cells challenged with encephalomyocarditis virus.

New [18F]Tracers for Alzheimer's Disease Imaging. Labeling Synthesis And Biological Testing

Alzheimer’s disease (AD) is the most common form of dementia. Characteristic changes in an AD brain are the formation of β-amyloid protein (Aβ) plaques and neurofibrillary tangles, though other alterations in the brain have also been connected to AD. No cure is available for AD and it is one of the leading causes of death among the elderly in developed countries. Liposomes are biocompatible and biodegradable spherical phospholipid bilayer vesicles that can enclose various compounds. Several functional groups can be attached on the surface of liposomes in order to achieve long-circulating target-specific liposomes. Liposomes can be utilized as drug carriers and vehicles for imaging agents. Positron emission tomography (PET) is a non-invasive imaging method to study biological processes in living organisms. In this study using nucleophilic 18F-labeling synthesis, various synthesis approaches and leaving groups for novel PET imaging tracers have been developed to target AD pathology in the brain. The tracers were the thioflavin derivative [18F]flutemetamol, curcumin derivative [18F]treg-curcumin, and functionalized [18F]nanoliposomes, which all target Aβ in the AD brain. These tracers were evaluated using transgenic AD mouse models. In addition, 18F-labeling synthesis was developed for a tracer targeting the S1P3 receptor. The chosen 18F-fluorination strategy had an effect on the radiochemical yield and specific activity of the tracers. [18F]Treg-curcumin and functionalized [18F]nanoliposomes had low uptake in AD mouse brain, whereas [18F]flutemetamol exhibited the appropriate properties for preclinical Aβ-imaging. All of these tracers can be utilized in studies of the pathology and treatment of AD and related diseases.

Biological activity of Serratia marcescens cytotoxin

Serratia marcescens cytotoxin was purified to homogeneity by ion-exchange chromatography on a DEAE Sepharose Fast Flow column, followed by gel filtration chromatography on a Sephadex G100 column. The molecular mass of the cytotoxin was estimated to be about 50 kDa. Some biological properties of the cytotoxin were analyzed and compared with well-characterized toxins, such as VT1, VT2 and CNF from Escherichia coli and hemolysin produced by S. marcescens. The sensitivity of the cell lines CHO, HeLa, HEp-2, Vero, BHK-21, MA 104 and J774 to the cytotoxin was determined by the cell viability assay using neutral red. CHO and HEp-2 were highly sensitive, with massive cellular death after 1 h of treatment, followed by BHK-21, HeLa, Vero and J774 cells, while MA 104 was insensitive to the toxin. Cytotoxin induced morphological changes such as cell rounding with cytoplasmic retraction and nuclear compactation which were evident 15 min after the addition of cytotoxin. The cytotoxic assays show that 15 min of treatment with the cytotoxin induced irreversible intoxication of the cells, determined by loss of cell viability. Concentrations of 2 CD50 (0.56 µg/ml) of purified cytotoxin did not present any hemolytic activity, showing that the cytotoxin is distinct from S. marcescens hemolysin. Antisera prepared against S. marcescens cytotoxin did not neutralize the cytotoxic activity of VT1, VT2 or CNF toxin, indicating that these toxins do not share antigenic determinants with cytotoxin. Moreover, we did not detect gene sequences for any of these toxins in S. marcescens by PCR assay. These results suggest that S. marcescens cytotoxin is not related to any of these toxins from E. coli.

Biological evaluation of recombinant human erythropoietin in pharmaceutical products

The potencies of mammalian cell-derived recombinant human erythropoietin pharmaceutical preparations, from a total of five manufacturers, were assessed by in vivo bioassay using standardized protocols. Eight-week-old normocythemic mice received a single subcutaneous injection followed by blood sampling 96 h later or multiple daily injections with blood sampling 24 h after the last injection. Reticulocyte counting by microscopic examination was employed as the end-point using the brilliant cresyl blue or selective hemolysis methods, together with automated flow cytometry. Different injection schedules were investigated and dose-response curves for the European Pharmacopoeia Biological Reference Preparation of erythropoietin were compared. Manual and automated methods of reticulocyte counting were correlated with respect to assay validity and precision. Using 8 mice per treatment group, intra-assay precision determined for all of the assays in the study showed coefficients of variation of 12.1-28.4% for the brilliant cresyl blue method, 14.1-30.8% for the selective hemolysis method and 8.5-19.7% for the flow cytometry method. Applying the single injection protocol, a combination of at least two independent assays was required to achieve the precision potency and confidence limits indicated by the manufacturers, while the multiple daily injection protocol yielded the same acceptable results within a single assay. Although the latter protocol using flow cytometry for reticulocyte counting gave more precise and reproducible results (intra-assay coefficients of variation: 5.9-14.2%), the well-characterized manual methods provide equally valid alternatives for the quality control of recombinant human erythropoietin therapeutic products.

Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells

Patients expressing estradiol receptors in melanoma cells have been reported to have a better prognosis. We therefore decided to investigate the in vitro effects of ß-estradiol and tamoxifen on the growth and tyrosinase activity of SK-Mel 23 human melanoma cells. Twenty-four-hour treatment with 0.4 nM ß-estradiol inhibited cell proliferation in 30% (0.70 ± 0.03 x 10(5) cells) and increased tyrosinase activity in 50% (7130.5 ± 376.5 cpm/10(5) cells), as compared to untreated cells (1.0 ± 0.05 x 10(5) cells and 4769 ± 25.5 cpm/10(5) cells, respectively). Both responses were completely (100%) blocked by 1 µM tamoxifen. Higher concentrations (up to 1.6 nM) or longer treatments (up to 72 h) did not result in a larger effect of the hormone on proliferation or tyrosinase activity. Competition binding assays demonstrated the presence of binding sites to [2,4,6,7-³H]-ß-estradiol, and that the tritiated analogue was displaced by the unlabeled hormone (1 nM to 100 µM, Kd = 0.14 µM, maximal displacement of 93%) or by 10 µM tamoxifen (displacement of 60%). ß-estradiol also increased the phosphorylated state of two proteins of 16 and 46 kDa, after 4-h treatment, as determined by Western blot. The absorbance of each band was 1.9- and 4-fold the controls, respectively, as determined with Image-Pro Plus software. Shorter incubation periods with ß-estradiol did not enhance phosporylation; after 6-h treatment with the hormone, the two proteins returned to the control phosphorylation levels. The growth inhibition promoted by estradiol may explain the better prognosis of melanoma-bearing women as compared to men, and open new perspectives for drug therapy.

The biological effects of high-pressure gas on the yeast transcriptome

The aim of the present study was to examine the feasibility of DNA microarray technology in an attempt to construct an evaluation system for determining gas toxicity using high-pressure conditions, as it is well known that pressure increases the concentration of a gas. As a first step, we used yeast (Saccharomyces cerevisiae) as the indicator organism and analyzed the mRNA expression profiles after exposure of yeast cells to nitrogen gas. Nitrogen gas was selected as a negative control since this gas has low toxicity. Yeast DNA microarray analysis revealed induction of genes whose products were localized to the membranes, and of genes that are involved in or contribute to energy production. Furthermore, we found that nitrogen gas significantly affected the transport system in the cells. Interestingly, nitrogen gas also resulted in induction of cold-shock responsive genes. These results suggest the possibility of applying yeast DNA microarray to gas bioassays up to 40 MPa. We therefore think that "bioassays" are ideal for use in environmental control and protection studies.