Chemical Composition Of Secretions Research Articles

Morphoanatomy, histochemical and secretions process of extrafloral nectaries in Joannesia princeps Vell. (Euphorbiaceae)

Joannesia princeps presents two acropetiolar glands, with topography and morphology similar to extrafloral nectaries (EFNs). In the present study we described the anatomy and the ultrastructure of acropetiolar glands, and analyzed the histochemistry and chemical composition of secretion in order to (i) verify if these glands are nectaries and (ii) understand the complexity of secretion and the cell compartment involved with the production and exudation. The samples were processed according to the standard methodology for anatomical and ultrastructural studies. The gland has uniseriate epidermis composed by palisade secretory cells. The secretion produced by the secretory epidermis is accumulated in a subcuticular space, which causes distention of the cuticle until it be broken, allowing the exudation. Xylem and phloem vascularize the gland, with the phloem reaching the nectariferous parenchyma, even close to the secretory epidermis. The histochemical tests revealed polysaccharides, mucilage and protein in the secretion, whereas the exudate chemical analysis showed that glucose, fructose and sucrose are components of the nectar, being fructose the sugar predominant. The secretion is complex and different organelles are involved in this synthesis and secretion process. Secretory parenchyma cells presented a large peripheral nucleus, vacuole with granular material, conspicuous endoplasmic reticulum, numerous mitochondria, plastids, and plasmodesmata. During the secretion process, a granular material is accumulated into the vacuole, which merges with the plasma membrane of the secretory epidermis, releasing this material into the periplasmatic spaces. After crossing the cell wall of the epidermal cell, the secretion is accumulated in a subcuticular space, until ready to be released by the cuticle disruption. Based on this study, we can affirm that the glands of it are extrafloral nectaries.

The chemical composition of the secretions, their antibacterial activity, and the pygidial gland morphology of selected European Carabini ground beetles (Coleoptera: Carabidae)

The pygidial glands of carabids produce strong-smelling vapours. In this study, we examined the chemical composition of the gland secretions and the structure of the glands in five species of Carabini ground beetles (one species from the subtribe Calosomatina and four species from the subtribe Carabina): Calosoma (Calosoma) maderae (Fabricius, 1775), Carabus (Carabus) granulatus Linnaeus, 1758, C. (Limnocarabus) clathratus Linnaeus, 1760, C. (Carabus) ulrichii Germar, 1823, and C. (Procerus) gigas Creutzer, 1799. Additionally, we tested the antibacterial potential of the pygidial gland secretions of the two latter species against 11 bacterial strains. In order to detect the chemical content of the secretions, we used gas chromatography–mass spectrometry (GC–MS). The secretion extracts were applied against selected strains of medically important bacteria. We used bright-field microscopy to examine the morphology of the glands. We discovered a total of 11 chemical compounds in the pygidial gland extracts of the ground beetles we analysed. Ten of these compounds were identified as seven carboxylic acids, two hydrocarbons, and one aromatic aldehyde, while one chemical remained unidentified. Most of the components were isolated from the secretion of C. (L.) clathratus (nine), while the lowest number of compounds was found in C. (P.) gigas (two). Methacrylic acid was the most dominant compound by percentage in all five species, while angelic acid was also detected in all samples. As expected, salicylaldehyde was exclusively found in the species of the genus Calosoma Weber, 1801. The secretion of C. (P.) gigas was shown to achieve the highest level of antibacterial activity against Pseudomonas aeruginosa, Salmonella enterica, and S. typhimurium (even the same level as the positive control streptomycin), while the secretion of C. (C.) ulrichii achieved the highest antimicrobial potential against Staphylococcus epidermidis, S. aureus, Listeria monocytogenes, and Bacillus cereus. The most noticeable difference in the structure of the glands between the two genera is that the reservoir in Calosoma is more significantly narrowed as it leads into the efferent duct, compared to that of Carabus.

On the Diversity of Semiochemicals of the Pygidial Gland Secretions of Subterranean Ground Beetles (Coleoptera: Carabidae)

Pygidial glands are of great importance to ground beetles for defense against predators, especially for the species that live in subterranean habitats. The purpose of our study is to better understand the chemistry of the pygidial gland secretions of subterranean ground beetles, as well as the function and structure of the glands. We studied both the chemical composition of the pygidial gland secretion and morphology of the glands in adults of the troglophilic ground beetle species Laemostenus (Antisphodrus) cavicola (Schaum, 1858). The chemical composition of its defensive secretion was revealed using gas chromatography-mass spectrometry (GC-MS), while pygidial gland morphology of the beetle was investigated using bright-field microcopy. In total, seven chemical compounds were detected in the secretion mixture. Formic acid was the most dominant compound, followed by dodecyl acetate and undecane. Other chemicals were present in minor amounts. The morphological structure of the pygidial glands of L. (A.) cavicola was compared with the structure of the glands of the related congeneric troglophilic species Laemostenus (Pristonychus) punctatus (Dejean, 1828). Summary data on the semiochemicals that have been recorded so far in subterranean ground beetle species are presented, and the differences in the chemical composition of the secretions between and among troglobitic and troglophilic species are discussed. So far, forty-four compounds have been detected in four subterranean ground beetle species (two troglobites belonging to the tribe Trechini and two troglophiles belonging to the tribe Sphodrini). The results of this study indicate the great diversity of chemicals in the pygidial gland secretions of subterranean ground beetles.

Патогенетична роль мікрофлори кишечника в розвитку ожиріння

The purpose of the study was to analyze the sources of modern literature of domestic and foreign researchers on the role of intestinal microbiota in the pathogenesis of obesity. Results and discussion. The number of patients with obesity and associated cardio-metabolic disorders such as arterial hypertension, dyslipidemia, coronary heart disease, type 2 diabetes mellitus is constantly increasing. The increase in the prevalence of obesity and metabolic disorders cannot be attributed solely to changes in the human genome, dietary habits, or reduced levels of physical activity. In addition to the generally recognized reasons, one of the factors affecting the microorganism’s energy homeostasis is the intestinal microbiota. Intestinal microbiota is a collection of bacteria that inhabit the gastrointestinal tract. Intestinal microbiota and its active metabolites are involved in intestinal and hepatic gluconeogenesis, in fat homeostasis, in the synthesis of incretin hormones, and influence on the appetite regulation. Short-chain fatty acids are the most important metabolites of intestinal microbiota. Some bacteria of the Firmicutes, Eubacterium rectale/Roseburia phylum and Faecalibacterium prausnitzii and others produce short-chain fatty acids. Short-chain fatty acids perform a detoxifying function, maintain water and electrolyte balance, and participate in immune response processes by reducing the synthesis of pro-inflammatory interleukins. Intestinal microbiota is also considered as one of the potential sources of metabolic endotoxemia formation. The role of endotoxin in the human body is performed by one of the components of the outer membrane of gram-negative bacteria – lipopolysaccharide. It is constantly present in the blood, and at “physiological” concentrations it maintains the balance of the immune system, and “excessive” concentration of lipopolysaccharide in the blood leads to low-grade inflammation, endothelial dysfunction, and other inflammation-associated conditions. The degree of endotoxemia positively correlates with the severity of negative changes in lipid and carbohydrate metabolism. Also, intestinal microbiota can send signals to the central nervous system through the enteric nervous system or through the afferent fibers of the nervus vagus, both directly and through the release of neurotransmitters into the bloodstream. In turn, when transmitting signals from top to bottom, the autonomic nervous system and the hypothalamus-pituitary-adrenal axis affects intestinal microbiota, probably due to changes in the chemical composition of secretions. Conclusion. Members of intestinal microbiota can inhibit the activity of the enzyme adenosine monophosphate-activated protein kinase in muscle and liver, which entails a decrease in fatty acid oxidation and an increase in body fat. As it turned out, almost all known cardiovascular risk factors are to a greater or lesser extent interconnected with the state of the intestinal microbiota, so understanding its role and methods for correcting the composition of the intestinal microbiota can be of great importance in solving important issues in medicine

Costs of injury for scent signalling in a strepsirrhine primate

Honesty is crucial in animal communication when signallers are conveying information about their condition. Condition dependence implies a cost to signal production; yet, evidence of such cost is scarce. We examined the effects of naturally occurring injury on the quality and salience of olfactory signals in ring-tailed lemurs (Lemur catta). Over a decade, we collected genital secretions from 23 (13 male, 10 female) adults across 34 unique injuries, owing primarily to intra-group fights. Using gas chromatography-mass spectrometry, we tested for differences in the chemical composition of secretions across pre-injury, injury and recovery, in animals that did and did not receive antibiotics. Lemur genital secretions were significantly dampened and altered during injury, with patterns of change varying by sex, season and antibiotics. Using behavioural bioassays (excluding odorants from antibiotic-treated animals), we showed that male ‘recipients’ discriminated injury status based on scent alone, directing more competitive counter marking towards odorants from injured vs. uninjured male ‘signallers.’ That injured animals could not maintain their normal signatures provides rare evidence of the energetic cost to signal production. That conspecifics detected olfactory-encoded ‘weakness’ suggests added behavioural costs: By influencing the likelihood of intra- or inter-sexual conflict, condition-dependent signals could have important implications for socio-reproductive behaviour.

Chemical signals in desert lizards: Are femoral gland secretions of male and female spiny-tailed lizards, Uromastyx aegyptia microlepis adapted to arid conditions?

Many lizards use femoral gland secretions in intraspecific chemical communication, but specific compounds have been identified in only a few species. Chemical composition of secretions may depend on phylogeny, but it may also evolve to maximize efficacy of signals in a given environment. In deserts, the extreme dry and hot environmental conditions are hostile for chemical signals and, therefore, we expected desert lizards to have secretions with highly stable compounds. Using GC–MS, we identified 74 lipophilic compounds in femoral secretions of male and female spiny-tailed lizards, Uromastyx aegyptia microlepis (Fam. Agamidae), from the Qatar desert. Compounds included mainly steroids and fatty acids, but also terpenoids, ketones, tocopherol, aldehydes and alcohols. We found differences between males and females; males had higher proportions of fatty acids and tocopherol, but lower proportions of ketones than females. Contrary to expectations, the most abundant compounds were not stable in the desert climatic conditions at the surface. However, secretions could be rather adapted to microclimatic conditions inside burrows where these lizards spend long periods of time. We suggest that in addition to phylogenetic and environmental characteristics, we should know the ecology of a lizard species before making generalizations on the potential characteristics of its chemical signals.

Ultrastructural detection of lipids in the cephalic salivary glands of Apis mellifera and Scaptotrigona postica (Hymenoptera: Apidae) workers

Secretory cells of the cephalic salivary glands (CSGs) of eusocial bees produce and accumulate lipid-like secretion in the lumens of their alveoli. Correspondingly, secretory cells present typical ultrastructural features of lipid-compound producers. Previous work on bees has revealed inter-specific differences in the chemical composition of secretion, and the production mechanisms and secretory cycle of secretory cells. In this work a comparative analysis of the mechanisms of lipid storage in the CSGs of Apis mellifera (Linnaeus, 1758) and Scaptotrigona postica (Latreille, 1807) workers was carried out. The ultrastructural location of lipids was ascertained using imidazole-osmium (IO), using individuals in different stages of their life cycles. Lipid deposits were identified inside glandular cells and in the alveolar lumens in all individuals, but differences were observed between the species. The glandular cells of A. mellifera workers presented positive reactions to IO as droplets dispersed in the cytoplasm, as vesicles and in the channels formed by apical plasma membrane infolds. In S. postica , lipid compounds were detected inside the mitochondrial matrix and in smooth endoplasmic reticulum cisterns. In both species, forager workers exhibited the largest amounts of lipids stored in the alveolar lumen. The differences between the species are discussed, taking into account specific behavioral differences.

ENVIRONMENTAL SCANNING ELECTRON MICROSCOPY (ESEM) OF Morinda citrifolia L. (Rubiaceae) COLLETERS

This study describes the colleters of <em>Morinda citrifolia L. </em>(Rubiaceae) by using environmental scanning electron microscopy (ESEM) and energy dispersive x-ray spectroscopy (EDS). Two different developmental stages were characterized as well as the chemical composition of secretion. Colleters are secretory structures that produce mucilage protecting the meristems and leaf primordia against desiccation and/or pathogens. Although these secretory structures are common on Rubiaceae, the results reported here is to the best of our knowledge the first record of colleters on <em>Morinda</em> genus. Colleters are present at the stipule adaxial surface, distributed in lines. These secretory structures are standard type and have no base constriction, differently from all studied species until now. In order to better understand the colleters structure and secretion, two phases were distinguished: a secretory phase and a senescence one. On secretory phase standard type colleters were visualized between leaf primordia and stipule, emerge on secretion. They present smooth surface, however was also possible to observe the contours of secretory cells anticlinal walls. In senescent phase colleters morphology was alternated exhibiting rough surface and blunt to point tips. The surface was rough and on stipule sections was possible to observe idioblasts with raphides bundles. The secretion process of <em>M. citrifolia </em>colleters occurs with the disruption of cuticle and the chemical elements are mostly dominated by carbon and oxygen.

Study on pathway and characteristics of ion secretion of salt glands of Limonium bicolor

Recretohalophytes with specialized salt-secreting structures, including salt glands and salt bladders, can secrete excess salts from plant tissues and enhance salinity tolerance of plants. However, the pathway and property of salt secretion by the salt gland has not been elucidated. In the article, Limonium bicolor Kuntze was used to investigate the pathway and characteristics of salt secretion of salt gland. Scanning electron microscope micrographs showed that each of the secretory cells had a pore in the center of the cuticle, and the rice grain-like secretions were observed above the pore. The chemical composition of secretions from secretory pores was mainly NaCl using environmental scanning electron microscope technique. Non-invasive micro-test technology was used to directly measure ion secretion rate of salt gland, and secretion rates of Na+ and Cl− were greatly enhanced by a 200-mmol/L NaCl treatment. However, epidermal cells and stoma showed little secretion of ions. In conclusion, our results provide evidence that the salt glands of L. bicolor have four secretory pores and that NaCl is secreted through these pores of salt gland.

Inter-island variation in femoral secretions of the Balearic lizard, Podarcis lilfordi (Lacertidae)

Many lizards use femoral gland secretions in intraspecific communication. Although there is a consistent interspecific variation in chemical composition of secretions, considerable variation is also often found between populations, which may affect conspecifc recognition and lead to speciation processes. Balearic lizards (Podarcis lilfordi) are currently distributed only in several isolated islets offshore of the main islands with different environmental conditions (vegetation, diet, density of population, etc). Also, there is a high genetic variability between populations. We examined whether there was a similar variation in the composition of the femoral secretions of male lizards, and which could be the causes of such variation. By using GC–MS analyses, we found 75 lipophilic compounds in femoral gland secretions of male P. lilfordi from three representative island populations. Main compounds were steroids (94.4%), mainly cholesterol, but we also found alkanes, ketones, waxy esters, squalene, carboxylic acids and their ethyl esters, alcohols and other minor compounds. However, there were clear differences between populations with respect to the number and relative proportions of compounds. Using the patterns of presence and abundance of compounds in secretions it is possible to predict the population of origin of a lizard. We discuss how these differences could be explained considering genetic and environmental differences between populations.

Effects of testosterone supplementation on chemical signals of male Iberian wall lizards: consequences for female mate choice

In some lizards, female mate choice is influenced by chemicals secreted by males, e.g., via the femoral glands. Secretions of the femoral glands are under direct androgenic control and vary seasonally with androgen production. However, whether increased testosterone (T) levels affect the concentration and chemical composition of secretions or their attractiveness to females is unknown. We manipulated T levels of male Iberian wall lizards, Podarcis hispanica, with silastic implants. Differential tongue-flick rates indicated that females detected and discriminated between femoral secretions of control and T-implanted males based on chemical cues alone. Females showed greater responses to secretions of T-males, which might suggest that T increased the concentration of chemical signals. Further analyses by gas chromatography–mass spectrometry indicated that T supplementation induced qualitative changes in lipid composition of femoral secretions. T-males had decreased relative proportions of cholesta-5,7-dien-3-ol in secretions, which might be related to the negative effects of T on the immune system and on lipid metabolism. However, experiments of choice of males’ scent showed that females neither preferred nor avoided the scent marks of T-males but preferred males that maintained higher proportions of cholesta-5,7-dien-3-ol in secretions, independently of the experimental manipulation. Thus, because this steroid is negatively affected by T, there might be trade-offs among increasing T levels to increase the production of chemical secretions, maintain metabolism, and attract females.

クモの糸の化学

The paper describes the following items ; (a) the construction of orb-web, (b) the chemical composition of secretions and the adhesive materials, (c) the toxin of spider, (d) the courtship and ferromon, (e) the thermal properties of spider's drag line, (f) the change in color of drag line. For example, the toxin of spider contains spermine whose existence is detected in human semen. The DSC curve between room temperature and 600°C shows that the spider's thread should be at least stable up to 200°C. The color of drag line changes from white to yellow with changing seasons from summer to autumn. The fact suggests a possibility that the color of spider's thread protects the spider from foreign invaders.

Individual and Sex Differences in the Chemical Composition of Pheromone-Like Substances from the Skin Glands of the Rabbit, Oryctolagus cuniculus

The chemical compositions of secretions from the anal, chin, and inguinal glands from 1450 rabbits, Oryctolagus cuniculus, caught in the field in Australia, were analyzed using gas chromatography, thin-layer chromatography, and electrophoresis on agar and polyacrylamide gels. Analyses were carried out on pure secretions obtained from anal and chin glands, on sebum scraped from the inguinal pouches, and on lipid extracts of homogenates prepared from whole glands. Differences in the chemical composition of secretions from separate types of glands were found. In addition, variations in the composition of the same type of gland related to sex, as well as variations between individuals were demonstrated. Gland secretions contained proteins and carbohydrates. Lipid extracts obtained from gland homogenates consisted of hydrocarbons, nonglyceryl esters, fatty acids, and cholesterol. Triglycerides, diglycerides and monoglycerides were also present in extracts from the chin gland and the sebaceous portions of the inguinal glands. The significance of the results is discussed briefly.