SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Gland

178

The assassin bug venom system plays diverse roles in prey capture, defence and extra-oral digestion, but it is poorly characterised, partly due to its anatomical complexity. Here we demonstrate that this complexity results from numerous adaptations that enable assassin bugs to modulate the composition of their venom in a context-dependent manner. Gland reconstructions from multimodal imaging reveal three distinct venom gland lumens: the anterior main gland (AMG); posterior main gland (PMG); and accessory gland (AG). Transcriptomic and proteomic experiments demonstrate that the AMG and PMG produce and accumulate distinct sets of venom proteins and peptides. PMG venom, which can be elicited by electrostimulation, potently paralyses and kills prey insects. In contrast, AMG venom elicited by harassment does not paralyse prey insects, suggesting a defensive role. Our data suggest that assassin bugs produce offensive and defensive venoms in anatomically distinct glands, an evolutionary adaptation that, to our knowledge, has not been described for any other venomous animal.

Concepts: Evolution, Gland, Hemiptera, Toxin, Caterpillar, Venom, Scorpion, Spider bite

123

Perspiration-based wearable biosensors facilitate continuous monitoring of individuals' health states with real-time and molecular-level insight. The inherent inaccessibility of sweat in sedentary individuals in large volume (≥10 µL) for on-demand and in situ analysis has limited our ability to capitalize on this noninvasive and rich source of information. A wearable and miniaturized iontophoresis interface is an excellent solution to overcome this barrier. The iontophoresis process involves delivery of stimulating agonists to the sweat glands with the aid of an electrical current. The challenge remains in devising an iontophoresis interface that can extract sufficient amount of sweat for robust sensing, without electrode corrosion and burning/causing discomfort in subjects. Here, we overcame this challenge through realizing an electrochemically enhanced iontophoresis interface, integrated in a wearable sweat analysis platform. This interface can be programmed to induce sweat with various secretion profiles for real-time analysis, a capability which can be exploited to advance our knowledge of the sweat gland physiology and the secretion process. To demonstrate the clinical value of our platform, human subject studies were performed in the context of the cystic fibrosis diagnosis and preliminary investigation of the blood/sweat glucose correlation. With our platform, we detected the elevated sweat electrolyte content of cystic fibrosis patients compared with that of healthy control subjects. Furthermore, our results indicate that oral glucose consumption in the fasting state is followed by increased glucose levels in both sweat and blood. Our solution opens the possibility for a broad range of noninvasive diagnostic and general population health monitoring applications.

Concepts: Health, Electrochemistry, Cystic fibrosis, Gland, Exocrine gland, Glands, Exocrine system, Sweat gland

90

We present an organoid regeneration assay in which freshly isolated human mammary epithelial cells are cultured in adherent or floating collagen gels, corresponding to a rigid or compliant matrix environment. In both conditions, luminal progenitors form spheres, whereas basal cells generate branched ductal structures. In compliant but not rigid collagen gels, branching ducts form alveoli at their tips, express basal and luminal markers at correct positions, and display contractility, which is required for alveologenesis. Thereby, branched structures generated in compliant collagen gels resemble terminal ductal-lobular units (TDLUs), the functional units of the mammary gland. Using the membrane metallo-endopeptidase CD10 as a surface marker enriches for TDLU formation and reveals the presence of stromal cells within the CD49f(hi)/EpCAM(-) population. In summary, we describe a defined in vitro assay system to quantify cells with regenerative potential and systematically investigate their interaction with the physical environment at distinct steps of morphogenesis.

Concepts: Epithelium, Basement membrane, Basal lamina, Natural environment, Cornea, Connective tissue, Gland, Exocrine gland

86

An important feature of the mammary gland is its ability to undergo repeated morphological changes during each reproductive cycle with profound tissue expansion in pregnancy and regression in involution. However, the mechanisms that determine the tissue’s cyclic regenerative capacity remain elusive. We have now discovered that Cre-Lox ablation of Rac1 in mammary epithelia causes gross enlargement of the epithelial tree and defective alveolar regeneration in a second pregnancy. Architectural defects arise because loss of Rac1 disrupts clearance in involution following the first lactation. We show that Rac1 is crucial for mammary alveolar epithelia to switch from secretion to a phagocytic mode and rapidly remove dying neighbors. Moreover, Rac1 restricts the extrusion of dying cells into the lumen, thus promoting their eradication by live phagocytic neighbors while within the epithelium. Without Rac1, residual milk and cell corpses flood the ductal network, causing gross dilation, chronic inflammation, and defective future regeneration.

Concepts: Prolactin, Secretion, Epithelium, Milk, Skin, Progesterone, Gland, Mammary gland

47

Amphibian skin is rich in mucous glands and poison glands, secreting substances important for gas exchange and playing a fundamental role in chemical defense against predators and microorganisms. In the caecilian Siphonops annulatus (Mikan, 1920) we observed a concentration of enlarged mucous glands in the head region. In the posterior region of the body a similar concentration is made up of enlarged poison glands. These accumulations of glands structurally resemble the macroglands previously reported in anurans and salamanders. The skin glands in these regions are each surrounded by collagen walls forming a honeycomb-like structure. The collagen network in the head region firmly attaches to tiny pits in the bones of the skull. The two extremities of the body produce different secretions, containing exclusive molecules. Considering the fossorial lifestyle of caecilians, it seems evident that the secretions of the head and caudal region serve different functions. The anterior macrogland of mucous glands, rich in mucous/lipid secretion, in conjunction with the funnel-shaped head, may act to lubricate the body and penetrate the soil, thus facilitating locomotion underground. The blunt posterior end bearing an internalized macrogland of poison glands in the dermis may act in chemical defense and/or by blocking invasion of tunnels.

Concepts: Secretion, Epithelium, Skin, Gland, Tetrapod, Amphibian, Caecilian, Caeciliidae

47

As tawny crazy ants (Nylanderia fulva) invade the southern USA, they often displace imported fire ants (Solenopsis invicta). Following exposure to S. invicta venom, N. fulva applies abdominal exocrine gland secretions to its cuticle. Bioassays reveal that these secretions detoxify S. invicta venom. Further, formic acid, from N. fulva venom, is the detoxifying agent. N. fulva exhibits this detoxification behavior after conflict with a variety of ant species; however, it expresses it most intensely after interactions with S. invicta. This behavior may have evolved in their shared South American native range. The unique capacity to detoxify a major competitor’s venom likely contributes substantially to its ability to displace S. invicta populations, making this behavior a causative agent in the ecological transformation of regional arthropod assemblages.

Concepts: Ecology, Gland, Exocrine gland, Ant, Red imported fire ant, Fire ant, Solenopsis daguerrei, Ants

28

The present study investigated the effect of the Iodoform-containing root canal filling material on the viability of cultured macrophages and epithelial cells, and on cytokine secretion.

Concepts: Cell, Cell biology, Epithelium, Gland

28

The presence of the leptin receptor (ObR) has already been highlighted in the human major salivary glands and it has been hypothesized that leptin may act by regulating the gland’s growth. No data are reported on domestic animals so, considering the important role that these glands play, not only related to food ingestion and digestion, and the important functional role hypothesized to explain the presence of ObR in humans salivary glands, the aim of the present work was to investigate the presence and the distribution of the leptin receptor in horse parotid and mandibular glands, by immunohistochemical techniques. The presence of ObR was evidenced in parotid and mandibular glands, exclusively localized in duct epithelial cells; their positivity was localized in the cytoplasm and was most evident near its apical portion. Immuno-positivity not only affects the intralobular ducts (intercalated and striated) but also the interlobular ones. Our results indicate that horse major salivary glands, like those of humans, are likely targets of leptin actions, suggesting a functional role of leptin on these glands.

Concepts: Protein, Digestive system, Epithelium, Gland, Glands, Parotid gland, Salivary gland, Submandibular gland

28

Adhesives that are naturally produced by marine organisms are potential sources of inspiration in the search for medical adhesives. Investigations of barnacle adhesives are at an early stage but it is becoming obvious that barnacles utilize a unique adhesive system compared to other marine organisms. The current study examined the fine structure and chemistry of the glandular system that produces the adhesive of the barnacle Lepas anatifera. All components for the glue originated from large single-cell glands (70-180 μm). Staining (including immunostaining) showed that L-3,4-dihydroxyphenylalanine and phosphoserine were not present in the glue producing tissues, demonstrating that the molecular adhesion of barnacles differs from all other permanently gluing marine animals studied to date. The glandular tissue and adhesive secretion primarily consisted of slightly acidic proteins but also included some carbohydrate. Adhesive proteins were stored in cytoplasmic granules adjacent to an intracellular drainage canal (ICC); observations implicated both merocrine and apocrine mechanisms in the transport of the secretion from the cell cytoplasm to the ICC. Inside the ICC, the secretion was no longer contained within granules but was a flocculent material which became “clumped” as it traveled through the canal network. Hemocytes were not seen within the adhesive “apparatus” (comprising of the glue producing cells and drainage canals), nor was there any structural mechanism by which additions such as hemocytes could be made to the secretion. The unicellular adhesive gland in barnacles is distinct from multicellular adhesive systems observed in marine animals such as mussels and tubeworms. Because the various components are not physically separated in the apparatus, the barnacle adhesive system appears to utilize completely different and unknown mechanisms for maintaining the liquid state of the glue within the body, as well as unidentified mechanisms for the conversion of extruded glue into hard cement. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.

Concepts: Cell, Secretion, Cytoplasm, Liquid, Gland, Exocrine gland, Adhesive, Animal glue

28

BACKGROUD: Perianal Paget’s disease is a rare malignant condition affecting the epidermal apocrine gland that is usually complicated, with a confusing clinical picture, and diagnosis is therefore often delayed. Although, more than 100 years has gone by since its first description by Darier and Coulillaud in 1893, proper treatment guidelines have yet to be established. OBJECTIVE: To review the available literature, emphasizing various current treatment strategies and aiming to increase clinicians' awareness of this rare disease, along with its management, for better practice and improvement of patient prognosis. METHODS: The review of the concerned literature was done by searching and compiling data available on PubMed, Medline, and other databases using the key words “perianal Paget’s disease,” “extramammary Paget’s disease,” “intraepithelial adenocarcinoma,” and “apocrine glands.” CONCLUSIONS: Surgery is the mainstay of treatment. Some noninvasive therapeutic modalities were also reported to be effective, such as photodynamic therapy, imiquimod, radiotherapy, chemotherapy, anti-androgen therapy, and carbon dioxide. Management of perianal Paget’s disease remains difficult, and large controlled, multicentric studies should be performed to compare the effectiveness of current thera-peutic modalities.

Concepts: Medicine, Carbon dioxide, Cancer, Surgery, Therapy, Gland, James Paget, Extramammary Paget's disease