Maxillary Gland Research Articles

The lymphatic vascular system of the mouse head.

Histological studies of the lymphatic vascular system in adult mice are hampered because bones cannot be sectioned properly. Here, we decalcified the heads of 14-day-old mice, embedded them in paraffin and stained resultant serial sections with the lymphendothelial-specific antibodies Lyve-1 and Podoplanin. We show that the tissues with the highest lymphatic vascular density are the dermis and the oral mucous membranes. In contrast, the nasal mucous membrane is devoid of lymphatics, except for its most basal parts below the vomeronasal organ. The inferior nasal turbinate contains numerous lymphatics and is connected to the nasolacrimal duct (NLD), which is ensheathed by a dense network of lymphatics. The lymphatics of the eye lids and conjunctiva are connected to those of the inferior nasal turbinate. We suggest that cerebro-spinal fluid (CSF) can drain via the optic nerve and NLD lymphatics, whereas CSF drained via the Fila olfactoria into the nasal mucous membrane is used for moisturization of the respiratory air. Tongue, palatine and buccal mucous membranes possess numerous lymphatics, whereas the dental pulp has none. Lymphatics are present in the maxillary gland and close to the temporomandibular joint, suggesting the augmentation of lymph flow by chewing and yawning. Lymphatics can also be found in the dura mater and in the dural septae entering into deeper parts of the brain. Our findings are discussed with regard to CSF drainage and potential routes for ocular tumor dissemination.

Functional morphology of the maxillary and propharyngeal glands of Monomorium pharaonis (L.)

The maxillary and propharyngeal gland of all 3 castes of Monomorium pharaonis were examined with light and electron microscopy. Although both glands possess a pouch in which secretion can be stored temporarily, a proper reservoir is lacking. The paired maxillary gland opens at the base of the maxilla and consists of 4 secretory cells, which are smaller in workers as compared to queens and males. A digestive role is unlikely as the gland is not directly linked to the digestive system and the amount of rER is negligible. The propharyngeal gland consists of 2 clusters of 16 secretory cells, which open in the pharyngeal atrium through a duct. Secretory cells are smallest in males. Two types of endoplasmic vesicles are observed around the end apparatus, suggesting a release of at least 2 substances. High levels of rER indicate the production of digestive enzymes as one of its functions. No differences between mated versus virgin queens were observed for both glands. Further experiments on chemical and behavioural essays can improve our understanding of the role of both glands in the ant colony. Literature on this topic is very inconsistent. We provide a survey to unravel this chaotic nomenclature issue.

Review of Alaskaentomon (Protura: Acerentomidae, Nipponentominae)

Abstract Our reexamination of AlaskaentomonNosek, 1977 demonstrated that the type species, Alaskaentomon fjellbergiNosek, 1977, and Alaskaentomon condeiNosek, 1981 are united in the presence of two granulated appendices on the calyx of the maxillary gland, filiform sensilium tl and very long sensilium a on foretarsus, presence of two pairs of A-setae on mesonotum and metanotum, and presence of medial posterior (Pc) seta on tergite VII and sternites VI–VII. They differ from each other in the position of foretarsal sensilla d and a′’, number of setae on tergite VII and sternites II–III, and position of P3 on tergites II–VI. The original descriptions are corrected and supplemented with new characters, including head chaetotaxy, seta length and porotaxy.

Revision ofVesiculentomon, Nosekientomonn. g. (Protura: Acerentomidae, Nipponentominae), and a Key to Genera of Nipponentominae

AbstractBased on recent reexamination of types, Vesiculentomon rusekiNosek, 1977, differs significantly from Vesiculentomon marshalliRusek, 1974, in composition and shape of maxillary gland, number of anterior setae on metanotum, and shape of foretarsal sensillum t1. A new genus Nosekientomon is erected for V. ruseki. Nosekientomon n. gen. is characterized by three pairs of anterior setae on the metanotum, claviform foretarsal sensillum t1, and a smooth globular vesicle on the calyx of the maxillary gland. Vesiculentomon Rusek has four pairs of anterior setae on the metanotum, baculiform foretarsal sensillum t1, and a large vesicle near the calyx with dense granulation along its narrow proximal part. The original descriptions are corrected and supplemented with new characters, including head chaetotaxy, setal lengths, and porotaxy. A key to world genera of Nipponentominae is provided.

Without Gills: Localization of Osmoregulatory Function in the CopepodEurytemora affinis

The Pancrustacea, which include crustaceans and hexapods, have successfully colonized marine, freshwater, and terrestrial habitats. While members of the class Malacostraca (e.g., crabs, shrimp) often display immense osmoregulatory capacities, more basally branching crustaceans (e.g., copepods, branchiopods) tend to possess less-specialized osmoregulatory structures that have been poorly characterized. Remarkably, some of these more basal taxa have also colonized diverse habitats. For instance, the copepod Eurytemora affinis has recently invaded freshwater habitats multiple times independently but lack obvious osmoregulatory structures. To explore localization of ion exchange, we performed silver staining, immunohistochemical staining, and transmission electron microscopy. Our results revealed localization of ion transport within the maxillary glands and on four pairs of swimming legs. Silver staining revealed ion exchange at the maxillary pores and on the endopods and exopods of swimming legs P1 through P4. Immunohistochemical assays localized ion transport enzymes V-type H(+)-ATPase and Na(+)/K(+)-ATPase in the maxillary glands and swimming legs as well. Finally, transmission electron microscopy identified specialized ionocytes within these anatomical regions. These investigations uncovered novel osmoregulatory structures at the swimming legs, which we designate the "Crusalis organs." Our findings identified specific tissues specialized for ion transport, potentially enabling this small crustacean to rapidly transition into freshwater habitats.

Hesperentomon yangi sp. n. from Jiangsu Province, Eastern China, with analyses of DNA barcodes (Protura, Acerentomata, Hesperentomidae)

Hesperentomon yangi sp. n. is described from eastern China. Its DNA barcodes are sequenced and compared to the similar species of the genus. Hesperentomon yangi sp. n. is characterized by 12 posterior setae on tergites II–VI, 8 posterior setae on sternites IV–VI (seta Pc absent), absence of seta sd4 on head, absence of seta P2a on tergite VII, 6 and 8 anterior setae on mesosternum and metasternum respectively, and few teeth on comb. It differs from Hesperentomon xiningense Bu & Yin, 2007 and Hesperentomon nanshanensis Bu & Yin, 2007 in the chaetotaxy of mesosternum and metanotum, maxillary gland, length and shape of some sensilla on foretarsus, as well as the body porotaxy. The genetic divergences of DNA barcodes sequences between Hesperentomon yangi sp. n., Hesperentomon xiningense and Hesperentomon nanshanensis are 24.1% on average, which is distinctly higher than the divergences between individuals of the new species (0.5%). Molecular data provide a solid evidence of the new species identified by the morphological characters.

Baculentulus xizangensissp. nov. from Tibet, China (Protura: Acerentomata, Berberentulidae) with a Key to the Group ofBaculentulusSPP. with Foretarsal Sensillum B'

Baculentulus xizangensis sp. nov. from Tibet Autonomous Region, China is described. The new species is characterized by the presence of sensillum b' on foretarsus, short sensillum a' , one pair of A-setae (AS) on tergite VII, one pair of P-setae (P1) on sternite I, and comb with few teeth and straight hind margin. It is similar to Baculentulus ogawai (Imadaté, 1965) from Thailand, but differs in the length of sensilla a' and b' shape of maxillary gland and comb, and in the chaetotaxy on sternite I. The key to the group of Baculentulus spp. with foretarsal sensillum b' present is provided.

Squeezers and Leaf-cutters: Differential Diversification and Degeneration of the Venom System in Toxicoferan Reptiles

Although it has been established that all toxicoferan squamates share a common venomous ancestor, it has remained unclear whether the maxillary and mandibular venom glands are evolving on separate gene expression trajectories or if they remain under shared genetic control. We show that identical transcripts are simultaneously expressed not only in the mandibular and maxillary glands, but also in the enigmatic snake rictal gland. Toxin molecular frameworks recovered in this study were three-finger toxin (3FTx), CRiSP, crotamine (beta-defensin), cobra venom factor, cystatin, epididymal secretory protein, kunitz, L-amino acid oxidase, lectin, renin aspartate protease, veficolin, and vespryn. We also discovered a novel low-molecular weight disulfide bridged peptide class in pythonid snake glands. In the iguanian lizards, the most highly expressed are potentially antimicrobial in nature (crotamine (beta-defensin) and cystatin), with crotamine (beta-defensin) also the most diverse. However, a number of proteins characterized from anguimorph lizards and caenophidian snakes with hemotoxic or neurotoxic activities were recruited in the common toxicoferan ancestor and remain expressed, albeit in low levels, even in the iguanian lizards. In contrast, the henophidian snakes express 3FTx and lectin toxins as the dominant transcripts. Even in the constricting pythonid and boid snakes, where the glands are predominantly mucous-secreting, low-levels of toxin transcripts can be detected. Venom thus appears to play little role in feeding behavior of most iguanian lizards or the powerful constricting snakes, and the low levels of expression argue against a defensive role. However, clearly the incipient or secondarily atrophied venom systems of these taxa may be a source of novel compounds useful in drug design and discovery.

New ways to go—nasal floor structures as channelling system for vomeronasal stimuli in the shrew (Sorex araneus, Mammalia)

The mammalian lateral nasal gland (LNG, also called Steno’s gland) is known to be one source of so-called odorant-binding proteins, which are suggested to work as vehicles to carry chemosensory stimuli within the nasal cavity in order to guide them to olfactory and vomeronasal sensory neurons. Up to now, a largely unattended and unanswered question is how the secretions of the LNG migrate between the glandular opening at the upper edge of the anterior lateral nasal wall and the more caudally located vomeronasal organ. In order to address this issue, the functional morphology of the rostral nasal cavity of Sorex araneus was investigated histologically. Special interest was laid on the opening region of the LNG in the vestibular region of the nose and its topological connection to a hitherto largely unnoticed nasal concha, the atrioturbinate. It appears that the atrioturbinate serves as a specialised channel that directs the secretions of the LNG pointedly towards the entrance of the vomeronasal organ. In addition, it was observed that—contrary to previous reports—the LNG in Sorex araneus is anatomically clearly separated from the maxillary sinus gland and does not invade the maxillary sinus.

A novel method for producing mono-biotinylated, biologically active neurotrophic factors: An essential reagent for single molecule study of axonal transport

In this report, we describe a novel method for producing mature and biologically active mono-biotinylated nerve growth factors (mBtNGF) that can be used for single molecule studies of real-time movement of neurotrophins within axons of neurons. We inserted an AviTag sequence into the C-terminal of the full length mouse preproNGF cDNA and cloned the fusion construct into a pcDNA3.1 mammalian expression vector. We also subcloned the Escherichia coli biotin ligase, BirA, into a pcDNA3.1 vector. These two plasmids were then transiently co-expressed in HEK293FT cells. As a result, the AviTag located in the C-terminal of preproNGF was selectively ligated to a single biotin by BirA. The prepro sequence of NGF was subsequently cleaved within the cell. Mature mono-biotinylated NGF (mBtNGF) was secreted into cell culture media and was purified using Ni resin. We carried out activity assays and our results showed that mBtNGF retained biological activities that were comparable to normal NGF purified from mouse sub maxillary glands. We further verified the biotinylation efficiency of mBtNGF and the level of non-biotinylated NGF was virtually undetectable in the final preparation. Finally, by conjugating to quantum-dot streptavidin, mBtNGF was successfully used for single molecule study of axonal NGF trafficking in neurons.

Sugaentulus andrzeji sp. nov. from Siberia, Russia (Protura: Acerentomidae: Acerentominae) and key to Acerentominae genera

Sugaentulus andrzeji sp. nov. is described from Siberia. The new species is characterized by the peculiar shape of maxillary gland and striate band and leaf-like sensilla on maxillary palps. The related S. masumii differs from the new species by the broader calyx with distinct extra appendix and slender sensilla on maxillary palps. Postembryonic development of chaetotaxy and porotaxy also is described.

Two new species of Protura (Protentomidae and Hesperentomidae) from Northeastern China

Two new species of Protura, Neocondeellum chaoyangensis (Protentomidae), from Changchun city, Jilin Province, and Hesperentomon liaoningensis (Hesperentomidae), from Xingcheng city, Liaoning Province, are added to the known proturan fauna of China. Neocondeellum chaoyangensis differs from other Neocondeellum species by the chaetotaxy, absence of indentations on the interior surface of acrostylus, and the width of the calyx of maxillary gland. Hesperentomon liaoningensis differs from all other Hesperentomon species by the shape of the pseudoculus.

Tissue-specific expression of a bHLH-PAS protein homologous to ARNT during the development of crustacean Daphnia magna

cDNAs encoding a Daphnia magna homolog of aryl hydrocarbon receptor nuclear translocator (ARNT) were isolated and the structural and functional features as well as the expression pattern of their product, DmagARNT, were analyzed. Among the known bHLH-PAS proteins, the deduced amino acid sequences of DmagARNT showed the highest degree of identity to that of Drosophila ARNT (TGO). Expression of DmagARNT in ARNT-lacking mouse Hepa-c4 cells resulted in the compensation for the loss of hypoxia response, suggesting the formation of a dimer with mouse HIF-1α and that the resulting heterodimer binds to the hypoxia-responsive elements (HRE), leading to transcription of the downstream luciferase gene. Expression of D. magna ARNT was evident at the middle to late stages of embryonic development (about 25 h to 48 h after ovulation) in several tissues, including a pair of the 1st antenna, 2nd antenna, 2nd maxilla, five pairs of the thoracic limbs, the central nerve system, anus, dorsal organ, maxillary gland, and carapace. As observed in other species, the D. magna ARNT is likely to function broadly as an expressed dimerization partner in developmental processes. In contrast, expression of ARNT in adult D. magna was limited to the epipodites of thoracic limbs, suggesting that ARNT plays a role solely in hypoxia response in adult Daphnia.

Ultrastructure of the maxillary organ ofScutigera coleoptrata (Chilopoda, Notostigmophora): Description of a multifunctional head organ

The maxillary organ of Scutigera coleoptrata was investigated using light microscopy, electron microscopy, and maceration techniques. Additionally, we compared the maxillary organ of S. coleoptrata with those of two other notostigmophoran centipedes, Parascutigera festiva and Allothereua maculata, using SEM. The maxillary organ is located inside the posterior coxal lobes of the first maxillae and extends posteriorly as sac-like pouches. The narrow epidermis of the maxillae is differentiated to form the epithelium of the maxillary organ. Two types of epithelia are distinguishable: a simple cuboidal epithelium of different height and differentiation (types I, II, IV) and a pseudostratified columnar epithelium (type III). These epithelia are covered by a highly specialized cuticle. The pseudostratified epithelium is the most prominent feature of the maxillary organ. It is covered with hundreds of setae, protruding deep into the maxillary organ. Two different types of setae can be distinguished, filiform and fusiform. The maxillary organ communicates with the oral cavity, the maxillary organ gland, the maxillary nephridium, and with a large number of epidermal glands that secrete into the maxillary organ. Epithelium III allows the extension of the maxillary organ when its pouches are filled with secretion. The maxillary organ is a complex multifunctional organ. The organ probably stores excretion from the maxillary nephridia and secretory fluid from the maxillary organ gland and other epidermal glands. The fluid is primarily required as preening fluid. The ammonia of the excretory fluid is thought to evaporate via the setae and the wide opening of the maxillary organ. It is likely that parts of the fluid can be reabsorbed by the animal via the oral cavity.

Early evolution of the venom system in lizards and snakes

Among extant reptiles only two lineages are known to have evolved venom delivery systems, the advanced snakes and helodermatid lizards (Gila Monster and Beaded Lizard). Evolution of the venom system is thought to underlie the impressive radiation of the advanced snakes (2,500 of 3,000 snake species). In contrast, the lizard venom system is thought to be restricted to just two species and to have evolved independently from the snake venom system. Here we report the presence of venom toxins in two additional lizard lineages (Monitor Lizards and Iguania) and show that all lineages possessing toxin-secreting oral glands form a clade, demonstrating a single early origin of the venom system in lizards and snakes. Construction of gland complementary-DNA libraries and phylogenetic analysis of transcripts revealed that nine toxin types are shared between lizards and snakes. Toxinological analyses of venom components from the Lace Monitor Varanus varius showed potent effects on blood pressure and clotting ability, bioactivities associated with a rapid loss of consciousness and extensive bleeding in prey. The iguanian lizard Pogona barbata retains characteristics of the ancestral venom system, namely serial, lobular non-compound venom-secreting glands on both the upper and lower jaws, whereas the advanced snakes and anguimorph lizards (including Monitor Lizards, Gila Monster and Beaded Lizard) have more derived venom systems characterized by the loss of the mandibular (lower) or maxillary (upper) glands. Demonstration that the snakes, iguanians and anguimorphs form a single clade provides overwhelming support for a single, early origin of the venom system in lizards and snakes. These results provide new insights into the evolution of the venom system in squamate reptiles and open new avenues for biomedical research and drug design using hitherto unexplored venom proteins.

Orbital Floor Reconstruction Using Calcium Phosphate Cement Paste: An Animal Study

Orbital floor defects were created in 10 New Zealand white rabbits and were reconstructed using an injectable calcium phosphate paste. These animals were euthanized at 2, 4, 8, and 12 months after implantation and were examined for biocompatibility and osteoconductivity. Grossly, implants were found to be adherent to the floor and covered with fibrous tissues. There was no sign of infection, extrusion, or migration of implant within the orbit and maxilla. The orbital floor was completely restored. Histological examination showed active new bone formation that encroached within the implant and gradually increased in density with time. Maxillary mucosa and glands were likewise reconstituted. Thin fibrovascular tissues were seen on top of and within the surface of the implant, and few to slight inflammatory cells were seen. Microradiography showed direct apposition between the new bone and the implant. These findings compare favorably with previously published reports on the biocompatibility and osteoconductivity of calcium phosphate cement. The authors believe that, together with ease of use and structural integrity, calcium phosphate paste can be useful in orbital floor reconstruction.

Physical and Behavioral Description of a Captive Saola, Pseudoryx nghetinhensis

Since the discovery of the saola, Pseudoryx nghetinhensis , in central Viet Nam in 1992, little has been learned about this new bovid's behavior or ecology, and its taxonomic position remains in question; some place it in the subfamily Bovinae, others in Caprinae. In January 1996, a pregnant female was captured in central Laos and placed in a nearby menagerie. This was the first adult saola seen by the outside world and provided an opportunity to gather basic information about the species. The animal survived 18 days, during which time notes were made of her morphology and behavior. Noteworthy among physical traits were size and complexity of her maxillary glands and presence of pored skin nodules corresponding to white markings on the face. The saola exhibited remarkably tame behavior among humans, but intense stereotyped reactions toward domestic dogs. Characteristics such as round pupils and presence of four mammae fell more into the pattern of Bovinae than Caprinae. Other traits such as unique development of the maxillary gland were unlike either subfamily. This was among thirteen saola known to have been captured in Viet Nam and Laos since 1994, all of which soon died except one that was released. Consequently, basic field studies of the animal's requirements should probably precede any further attempts at live capture.

Metabolism-dependent activation and toxicity of chemicals in nasal glands

The mucosae of the nasal passages contain a large amount of glands which express secretory proteins as well as phase I and phase II biotransformation enzymes. In this review the metabolic activation, covalent binding and toxicity of chemicals in the Bowman's glands in the olfactory mucosa, in the sero-mucous glands in the nasal septum and in the lateral nasal glands and maxillary glands around the maxillary sinuses are discussed. Light microscopic autoradiographic studies have demonstrated a selective covalent binding of nasal toxicants and carcinogens such as halogenated hydrocarbons and N-nitrosamines, especially in the Bowman's glands following a single systemic exposure, suggesting a high rate of metabolic activation of chemicals in these glands. Special attention is put on the herbicide dichlobenil which induces necrosis in the olfactory mucosa following a cytochrome-P450-mediated metabolic activation and covalent binding in the Bowman's glands.

Discovery of Segmental Extranephridial Podocytes in Harpacticoida (Copepoda) and Bathynellacea (Syncarida)

ABSTRACT Segmental podocytes are reported for the first time to occur in the basal part of the pereiopods of different harpacticoid copepod species. In yet another species, segmental podocytes lie in the pleural folds, but also in closest vicinity to the pereiopods. The ultrastructure of these cells resembles not only that of other Crustacea (Isopoda, Cephalocarida, Decapoda), but also that of podocytes of the crustacean maxillary gland, as well as that of the of the Insecta. These results, together with the confirmation that the segmentally arranged so-called nephrocytes in the Bathynellacea (Syncarida) are in fact podocytes, support the view of a crustacean ancestor with segmental nephridial organs.

Submucosal glands after maxillary sinus surgery. An experimental study in rabbits.

Thirty New Zealand White rabbits underwent unilateral partial or complete removal of maxillary sinus mucosa in order to evaluate submucosal maxillary sinus glands. After three months, specimens were taken for examination from all operated on and control sinuses. Bacteriological cultures, light and electron microscopy were performed. Histopathological findings showed a decrease in the number of serous glands and significant inflammation was present in the sinus in which there was complete surgical removal. Electron microscopy revealed changes in the secretory cells of the serous glands in the regenerated post-surgical mucosa.