Chemical diversity and potential biological functions of the pygidial gland secretions in two species of Neotropical dung roller beetles

Dung roller beetles of the genus Canthon (Coleoptera: Scarabaeinae) emit an odorous secretion from a pair of pygidial glands. To investigate the chemical composition of these secretions, we used stir bar sorptive extraction (SBSE), coupled with gas chromatography–mass spectrometry (GC–MS) for analysis of extracts of pygidial gland secretions secreted by the dung roller beetles Canthon femoralis femoralis and Canthon cyanellus cyanellus. Chemical analyses of volatiles collected from pygidial gland secretions comprise a great diversity of the functional groups. Chemical profile comparisons showed high intra- and interspecific variability. The pygidial gland secretion of Canthon f. femoralis was dominated by sesquiterpene hydrocarbons, whereas the profile of Canthon c. cyanellus was dominated by carboxylic acids. The different pygidial secretions have a high diversity of chemical compounds suggesting a multifunctional nature involving some key functions in the biology. We discuss the biological potential of these compounds found in the pygidial glands of each species with respect to their ecological and behavioral relevance.

Chemical Composition of Metapleural Gland Secretions of Fungus-Growing and Non-fungus-growing Ants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Decreasing pH of mammary gland secretions is associated with parturition and is correlated with electrolyte concentrations in prefoaling mares

The objectives of this study were to determine pH of the mammary gland secretions and the corresponding electrolyte concentrations in prefoaling mares. Pregnant mares (seven primiparous and seven multiparous) were monitored daily from 310.320 days of gestation until parturition. Prefoaling mammary gland secretions were collected, and pH was immediately determined with a pH meter and pH strip test. An aliquot of prefoaling mammary secretions was frozen and stored until further analyses. After parturition, samples from day .4 to 0 (day of foaling) were thawed and electrolyte concentrations (ie, Ca2+, Mg2+, Na+, K+ and Cl-) were determined with an automated analyser. Data were analysed via a mixed model with the mare as a random effect. Correlations were determined between pH and electrolyte concentrations by the Pearson product-moment for each pair. There was significant reduction in pH of mammary secretions on the day of foaling (P<0.0001), and most mares (11/14) with a pH .7 foaled within 24 hours. There was high correlation between the two pH methods (r=0.93). Additionally, there were significant (P<0.05) increases in Ca2+ and K+ concentrations, and significant decreases in Na+ and Cl- concentrations from one day before to the day of foaling. The pH of mammary secretions was highly and significantly (P<0.001) correlated with Na + (r=0.87), Cl- (r=0.85), Ca2+ (r=-0.88); and K+(r=.0.80) concentrations, and moderately correlated with Mg 2+ (r=-0.58). Daily evening pH measure of the mammary gland secretions can predict foaling in most mares.

Submucosal gland secretions in airways from cystic fibrosis patients have normal [Na+] and pH but elevated viscosity

Fluid and macromolecule secretion by submucosal glands in mammalian airways is believed to be important in normal airway physiology and in the pathophysiology of cystic fibrosis (CF). An in situ fluorescence method was applied to measure the ionic composition and viscosity of freshly secreted fluid from airway glands. Fragments of human large airways obtained at the time of lung transplantation were mounted in a humidified perfusion chamber and the mucosal surface was covered by a thin layer of oil. Individual droplets of secreted fluid were microinjected with fluorescent indicators for measurement of [Na+], [Cl−], and pH by ratio imaging fluorescence microscopy and viscosity by fluorescence recovery after photobleaching. After carbachol stimulation, 0.1–0.5 μl of fluid accumulated in spherical droplets at gland orifices in ≈3–5 min. In gland fluid from normal human airways, [Na+] was 94 ± 8 mM, [Cl−] was 92 ± 12 mM, and pH was 6.97 ± 0.06 (SE, n = 7 humans, more than five glands studied per sample). Apparent fluid viscosity was 2.7 ± 0.3-fold greater than that of saline. Neither [Na+] nor pH differed in gland fluid from CF airways, but viscosity was significantly elevated by ≈2-fold compared to normal airways. These results represent the first direct measurements of ionic composition and viscosity in uncontaminated human gland secretions and indicate similar [Na+], [Cl−], and pH to that in the airway surface liquid. The elevated gland fluid viscosity in CF may be an important factor promoting bacterial colonization and airway disease.

Function of the Dufour's gland in solitary and social Hymenoptera

The poison gland and Dufour's gland are the two glands associated with the sting apparatus in female Apocrita (Hymenoptera). While the poison gland usually functions as an integral part of the venom delivery system, the Dufour's gland has been found to differ in its function in various hymenopteran groups. Like all exocrine glands, the function of the Dufour's gland is to secrete chemicals, but the nature and function of the secretions varies in different taxa. Functions of the Dufour's gland secretions range from serving as a component of material used in nest building, larval food, and pheromones involved in communicative functions that are important for both solitary and social species. This review summarizes the different functions reported for the Dufour's gland in hymenopterans, illustrating how the Dufour's gland secretions can be adapted to give rise to various functions in response to different challenges posed by the ways of life followed by different taxa. Aspects of development, structure, chemistry and the evolution of different functions are also touched upon briefly.

Cloning from tissue surrogates: antimicrobial peptide (esculentin) cDNAs from the defensive skin secretions of Chinese ranid frogs

The defensive skin secretions of amphibians are a rich source of bioactive peptides. Here we describe a rapid technique for skin granular gland transcriptome cloning from a surrogate tissue-the secretion itself. cDNA libraries were constructed from lyophilized skin secretion from each of the Chinese frogs (Rana schmackeri, Rana versabilis, and Rana plancyi fukienensis) using magnetic oligo(dT) bead-captured polyadenylated mRNA as templates. Specific esculentin cDNAs were amplified by 3'-RACE using a degenerate primer designed for a consensus nucleotide sequence in the 5' untranslated region of previously characterized ranid frog peptide cDNAs. The cloned cDNAs were found to encode the antimicrobial peptides esculentins 1 and 2 from each of the species examined. The presence of predicted peptide structures in skin secretions was confirmed by MALDI-TOF mass spectrometry and automated Edman degradation. This experimental approach can thus rapidly expedite parallel transcriptome and peptidome analysis of amphibian granular gland secretions without harming or sacrificing donor animals.

The chemical composition of the mandibular gland secretion of Melipona bicolor lepeletier, 1836 (Hymenoptera, Apidae, Meliponini): A comparative study among castes and sexes

The mandibular gland secretions of newly emerged, nurse and forager workers, virgin and physogastric queens and males of Melipona bicolor were analyzed by gas chromatography-mass spectrometry. The secretion is composed of a blend of hydrocarbons, alcohols, esters, and acids. The secretion is caste-sex specific and also differs with the tasks performed by the workers and the physiological reproductive condition of the queens.

Correlation between mandibular gland secretion and cuticular hydrocarbons in the stingless bee Melipona quadrifasciata

We investigated whether Melipona quadrifasciata worker mandibular gland secretions contribute directly to their cuticular hydrocarbon profile. The mandibular gland secretion composition and cuticular surface compounds of newly emerged worker bees, nurse bees, and foragers were determined by gas chromatography and mass spectrometry and compared. Both the mandibular gland secretions and the cuticular surface compounds of all worker stages were found to be composed almost exclusively of hydrocarbons. Although the relative proportion of hydrocarbons from the cuticular surface and gland secretion was statistically different, there was a high similarity in the qualitative composition between these structures in all groups of bees. © FUNPEC-RP.

Correlation between mandibular gland secretion and cuticular hydrocarbons in the stingless bee Melipona quadrifasciata

We investigated whether Melipona quadrifasciata worker mandibular gland secretions contribute directly to their cuticular hydrocarbon profile. The mandibular gland secretion composition and cuticular surface compounds of newly emerged worker bees, nurse bees, and foragers were determined by gas chromatography and mass spectrometry and compared. Both the mandibular gland secretions and the cuticular surface compounds of all worker stages were found to be composed almost exclusively of hydrocarbons. Although the relative proportion of hydrocarbons from the cuticular surface and gland secretion was statistically different, there was a high similarity in the qualitative composition between these structures in all groups of bees.

Tear analysis and lens-tear interactions:part II. Ocular lipids-nature and fate of meibomian gland phospholipids

Purpose: Published data indicate that the polar lipid content of human meibomian gland secretions (MGS) could be anything between 0.5% and 13% of the total lipid. The tear film phospholipid composition has not been studied in great detail and it has been understood that the relative proportions of lipids in MGS would be maintained in the tear film. The purpose of this work was to determine the concentration of phospholipids in the human tear film. Methods: Liquid chromatography mass spectrometry (LCMS) and thin layer chromatography (TLC) were used to determine the concentration of phospholipid in the tear film. Additionally, an Amplex Red phosphatidylcholine-specific phospholipase C (PLC) assay kit was used for determination of the activity of PLC in the tear film. Results: Phospholipids were not detected in any of the tested human tear samples with the low limit of detection being 1.3 µg/mL for TLC and 4 µg/mL for liquid chromatography mass spectrometry. TLC indicated that diacylglycerol (DAG) may be present in the tear film. PLC was in the tear film with an activity determined at approximately 15 mU/mL, equivalent to the removal of head groups from phosphatidylcholine at a rate of approximately 15 µM/min. Conclusions: This work shows that phospholipid was not detected in any of the tested human tear samples (above the lower limits of detection as described) and suggests the presence of DAG in the tear film. DAG is known to be at low concentrations in MGS. These observations indicate that PLC may play a role in modulating the tear film phospholipid concentration.

Automated surface sampling of lipids from worn contact lenses coupled with tandem mass spectrometry

The deposition of biological material (biofouling) onto polymeric contact lenses is thought to be a major contributor to lens discomfort and hence discontinuation of wear. We describe a method to characterize lipid deposits directly from worn contact lenses utilizing liquid extraction surface analysis coupled to tandem mass spectrometry (LESA-MS/MS). This technique effected facile and reproducible extraction of lipids from the contact lens surfaces and identified lipid molecular species representing all major classes present in human tear film. Our data show that LESA-MS/MS is a rapid and comprehensive technique for the characterization of lipid-related biofouling on polymer surfaces.

Investigation of biofilm production and icaA and icaD genes in Staphylococcus aureus isolated from heifers and cows with mastitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Associação da geoprópolis à quimioterápicos: ação citotóxica e antiproliferativa sobre células HEp-2 e mecanismos envolvidos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microbiologic characterization of equine mastitis

Mastitis occurrence in mares is low if compared to other livestock species. The microorganisms often isolated and detected in milk and mammary gland secretions of mares are Streptococcus beta-haemolytica, Staphylococcus spp., Pseudomonas aeruginosa, Actinobacillus spp., and enterobacter. The present experiment was designed to evaluate the main microorganisms present in the milk of healthy mares and having a mammary infection. One hundred and ten mammary glands from 55 lactating mares were analyzed, ranging from 15 to 150 d post-partum. The mastitis diagnostic was performed through analysis of the milk via the screened test of the mug with dark background (Tamis), mammary gland inflammation and/or systemic signs. The subclinical mammary gland infection was characterized via the California Mastitis Test (CMT). From the 55 lactating mares, 2 (3.64%) had clinical mastitis. Following the CMT, the mares presented: 13 (23.60%), 7 (12.72%), and 12 (21.88%) scores from 1+, 2+, and 3+, respectively. From the 110 mamary glands were analysed, in 47 (85.45%) of these samples strains of microorganisms were isolated. In summary, results from our experiment suggest a low occurrence of clinical mastitis in lactating mares.