Proboscis lateralis: a case report

A lateral proboscis usually occurs in the region of the inner canthus. We present a case of holoprosencephaly accompanied by an oblique facial cleft and an anterior encephalocele in which a proboscis lateralis occurred in a very lateral location.     

Nasal fossa malformations and paramedian facial cleft: new perspectives.

Choanal atresia may be associated with other cranio-facial malformations, including various degrees of nasal fossa malformation, and may be a part of paramedian facial clefts (as described by Tessier et al. [1977]). We identified five such cases with combined clinical elements corresponding to Tessier's paramedian facial cleft, including eyelid coloboma, mild to severe choanal and nasal fossa anomalies, ethmoidal hypoplasia and anterior skull base malformation, sometimes with proboscis lateralis and half-nose hypoplasia. These observations incited us, first, to elaborate a conception which accounts for the likely embryological mechanisms involved; second, to propose a new classification based on anatomical and pathogenic embryological considerations; and last, to propose the use of transpalatal approach to restore choanal permeability, since endonasal laser therapy is particularly dangerous in such cases.     

A comparative survey of proboscis morphology and associated structures in fruit-piercing, tear-feeding, and blood-feeding moths in Calpinae (Lepidoptera: Erebidae)

Functional feeding categories for adult species of Calpinae are described. Structures associated with the proboscis were examined using exemplar species in fruit-piercing, blood-feeding, and tear-feeding species using both light microscopy and SEM methods. At least three genera currently placed in Calpini, and several others in related groups lack specialized piercing structures. The proboscis of the tear-feeding species, Hemiceratoides hieroglyphica, is equipped with specialized cuticular hooks not yet observed in other tear-feeding species. Tearing hooks moveable by blood pressure are restricted to Calpini species, and little additional variation within this taxon exists, suggesting proboscis morphology may not be strongly correlated with feeding behavior (e.g., fruit piercing vs. blood feeding). A glossary of terms and character codings for proboscis structures is provided, and morphologies for all included calpine taxa are described. We discuss the taxonomic significance of proboscis morphology in Calpinae and the evolutionary implications of their associated feeding behaviors. This survey indicates morphology provides powerful prediction, but not proof of lepidopteran adult food habits.     

Experimental study of visual projection specificity in microphthalm and monophthalm embryos and adults of Gallus domesticus L.]

Research was carried out into the visual projections of embryos and chickens of Gallus domesticus L. who had undergone early optic vesicle removal and into microphthalmy or monophthalmy with ipsilateral optic fibres resulting from such removal. The architectonics of primary visual centres (nuclei ectomamillaris, geniculatus lateralis, lateralis anterior superficialis synencephali, griseus tectalis and the tectum opticum superficiale) and of the isthmo-opticus nucleus were compared with the architectonics of the same centres in anophthalms. From this research it can be seen that:--1. Optic fibres coming from limited ocular formation in microphthalms can reach the ectomamillaris nucleus in most cases and sustain existence; they may reach the tectum opticum without playing a qualitatively discernable morphogenetic role and act upon the isthmo-opticus nucleus. For these microphthalms, the nuclei lateralis anterior, geniculatus lateralis, superficialis synencephali and griseus tectalis are comparable to those of anophthalms. 2. Ipsilateral optic fibers can develop and show the same specificity and morphogenetic function as the microphthalms' optic fibres. 3. After hatching, some anophthalms shows an isthmo-opticus nucleus with scores of neurons. In general, observations during this research have shown that the specificity of microphthalms' optic fibres and ipsilateral optic fibres remain strictly the same whatever the operation under consideration.     

Structural insights into the processivity of endopolygalacturonase I from Aspergillus niger

Endopolygalacturonase I is a processive enzyme, while the 60% sequence identical endopolygalacturonase II is not. The 1.70 A resolution crystal structure of endopolygalacturonase I reveals a narrowed substrate binding cleft. In addition, Arg96, a residue in this cleft previously shown to be critical for processivity, interacts with the substrate mimics glycerol and sulfate in several well-defined conformations in the six molecules in the asymmetric unit. From this we conclude that both Arg96 and the narrowed substrate binding cleft contribute to retaining the substrate while it moves through the active site after a cleavage event has occurred.     

The Proboscis Armature of Turbellaria-Kalyptorhynchia,a Derivative of the Basement Lamina?

The fine structure analysis of the proboscis teeth in the genus Carcharodorhynchus Meixner and of the proboscis hooks in the genus Diascorhynchus Meixner revealed that these structures are not derived from local cuticularizations of the epidermis, but rather are closely associated with the basement lamina of the proboscis sheath epithelium. In Diascorhynchus the hooks are specializations within the basement lamina enclosing the proboscis. The proboscis teeth in Carcharodorhynchus seem to be either an intracellular differentiation within the modified proboscis sheath epithelium or, as in Diascorhynchus , a derivative of the basement lamina. The latter is supported by the finding of similar, dermal teeth clearly derived from the basement lamina in the body wall of several species of the genus Carcharodorhynchus. It appears from this study that most "cutic-ular" differentiations of the body wall in Turbellaria are either derivatives of the basement lamina or of the cytoplasm of the epidermis cells. These considerations are discussed in the light of possible evolutionary pathways leading from a ciliated epidermis (e.g. free-living acoelomates) to a cuticularized hypodermis (e.g. Aschelmimhes and Articulata).     

Metamorphic remodeling of a planktotrophic larva to produce the predatory feeding system of a cone snail (Mollusca, Neogastropoda)

I used histological sections and 3D reconstructions to document development through metamorphosis of the foregut and proboscis in the conoidean neogastropod Conus lividus. A goal was to determine how highly derived features of the post-metamorphic feeding system of this gastropod predator develop without interfering with larval structures for microherbivory. A second goal was to compare foregut development in this conoidean with previous observations on foregut development in the buccinoidean neogastropod Nassarius mendicus. These two neogastropods both have a feeding larval stage, but they show major differences in post-metamorphic foregut morphology. Basic events in development of the proboscis and proboscis sheath in C. lividus and N. mendicus were similar. However, the elongate buccal tube of C. lividus forms during metamorphosis as a composite of apical epidermal tissue that grows inward and ventral foregut tissue that extends outward. The larval mouth is not carried through metamorphosis. Comparative observations on foregut development in caenogastropods, which now include data on C. lividus, suggest that the foregut incorporates dorsal and ventral modules having different ontogenetic and functional fates. This developmental modularity may have facilitated evolutionary diversification of the post-metamorphic foregut. Foregut diversification in predatory gastropods may have been further fast-tracked by developmental uncoupling of larval and post-metamorphic mouths.     

THE TOXOGLOSSAN PROBOSCIS: STRUCTURE AND FUNCTION

The structure of the proboscis and anterior alimentary systemis described and reviewed in the three families (Conidae, Terebridae,Turridae) of the Conoidea (=Toxoglossa). A number of proboscisforms are shown, characterized by the presence of a permanentrhynchodeum, modified alimentary system and a venom apparatus.Despite the diversity of prey types in the Conidae (polychaetes,molluscs and fish) they have a uniform proboscis structure witha long buccal tube and functional buccal and venom apparati.This homogeneity is not present in the Turridae and the Terebridaewhich show a variety of proboscis structures. Terebrids feedonly on polychaetes or hemichordates but appear to have threeprimary feeding modes based on significant difference in thestructure and function of the buccal tube and associated buccalorgans. The greatest variety of proboscis type is found in thediverse Turridae which feed mainly on polychaetes, but includesipunculans, gastropods and nemerteans in their diet.     

Retinofugal projections in salamanders of the family Plethodontidae

Summary A comparison of the retinofugal projections in 14 species of plethodontid salamanders by means of the horseradish peroxidase (HRP) technique revealed almost identical contralateral projections. In all species studied three optic tracts were found. Behind the chiasma opticum the basal optic tract runs to the peduncle region, there forming the basal optic neuropil. The marginal optic tract courses from the chiasma over the thalamus to the tectum opticum where it covers the entire surface. In the anterior thalamus the marginal optic tract innervates the neuropil Bellonci-pars lateralis and the corpus geniculatum thalamicum, and more caudally the neuropil posterior thalami. The medial optic tract supplies the neuropil Bellonci-pars lateralis and pars medialis in the anterior thalamus from where it runs medial to the marginal optic tract as a separate tract to the uncinate field in the posterior thalamus.The ipsilateral projections show differences among the species studied, although the global organization remains constant. The differences mainly concern the marginal optic tract which varies from being weakly labeled and restricted to the rostral part of the tectum opticum, to being heavily labeled and innervating the entire tectum to its caudal edge. Species with the heaviest ipsilateral projections all belong to the plethodontid tribe Bolitoglossini, all of which show direct development, a highly projectile tongue, rather frontally oriented eyes and excellent depth perception. In these species the thalamic ipsilateral projection areas are equal in size and shape to the contralateral one. The ipsilateral projections to the tectum show two distinct layers, a superficial and a deep one, which intermingle with the contralateral projections. The two other ipsilateral tracts do not differ significantly among the plethodontid species: the medial optic tract is always heavily and the basal optic tract always weakly labeled.     

Flies and concealed nectar sources: morphological innovations in the proboscis of Bombyliidae (Diptera)

Bee-flies (Bombyliidae) have morphological adaptations of the mouthparts to particular floral traits. To investigate this the short, plesiomorphic proboscis of Hemipenthes morio was compared with the long, apomorphic proboscis of Bombylius major . A novel feeding position enables B. major to use flowers that open to the side as additional nectar sources. The new horizontal feeding position is enabled by the prolonged ventral base of the proboscis. Bombylius major exploits deep corolla tubes with an elongate proboscis, and an increased efficiency in both the suction pumps and the sealing mechanisms of the proboscis. The exploitation of narrow corolla tubes is made possible by the shift from a sponging feeding mode, exhibited by H. morio , to the exclusively sucking mode in B. major . Besides quantitative changes in the proportions of the different proboscis components, labellar movements as well as the structures of saliva distribution are changed along with this shift. The labial musculature of B. major does not significantly differ from the plesiomorphic state, since both examined species do not only feed on nectar, but also on pollen.     

3H]-GABA selective retrograde labeling of neurons in the pigeon thalamo-Wulst pathway

Evidence is presented which is consistent with a specific retrograde labeling of GABAergic neurons following [3H]-GABA application in their zone of termination. [3H]-GABA injection in the pigeon Wulst leads to perikaryal retrograde labeling in the ipsilateral thalamic visual relay, n. dorsolateralis anterior thalami, pars lateralis (DLLv). This result gives further support to the biochemical evidence of the existence, in the pigeon, of a GABAergic projection from DLLv to the ipsilateral visual Wulst.     

True median cleft of the upper lip associated with three pedunculated club-shaped skin masses

A rare case of true median cleft of the upper lip associated with three skin masses is reported. While 114 cases of median cleft of the upper lip have been reported, in our literature review we found only 1 case, reported by Sharma, in which the median cleft was associated with skin masses. The embryology of this case is also discussed.     

Feeding of the Cymatiid Gastropod, Argobuccinum argus, in Relation to the Structure of the Proboscis and Secretions of the Proboscis Gland

Several gastropod families belonging to the superfamily Tonnaceaare known to bore into the calcareous shells of echinoids andbivalves, but little work has been done on the family Cymatiidae.New observations show that the cymatiid, Argobuccinum argus,which feeds on the tubicolous polychaete, Gunnarea capensis,possesses large proboscis glands which secrete 0.4 to 0.5N H₂SO₄;further, the secretion dissolves greater amounts of pure CaCO₃than does O.47N H₂SO₄, alone. A toxin is also present, whichabolishes responses to light and touch in several invertebrates. The proboscis is atypically pleurembolic, having a permanentproboscis sheath. Retraction is due to the muscles ot the probosciswall, and the contracted proboscis is not inverted. Unlike othermesogastropods, the Tonnacea have three pairs ofglands associatedwith the foregut: proboscis glands, true salivary glands, anda small, partly paired gland of unknown function immediatelyposterior to the buccal mass. It is concluded that because of an abundance of readily availablefood in the form of Gunnarea, A. argus does not drillinto animalsprotected by a calcareous shell. The presence of a CaCO₃ dissolvingmechanism indicates that the Cymatiidae ingeneral may be ableto employ this method of feeding.     

Mouthparts of heliconius butterflies (LEPIDOPTERA : NYMPHALIDAE) : a search for anatomical adaptations to pollen-feeding behavior

Proboscis length, the length of the tip, the number and length of the various sensilla throughout the proboscis, and the size and shape of the labial palpi were compared in 25 species of pollen-feeding and non-pollen-feeding Heliconiinae (Lepidoptera, Nymphalidae). The mouthparts of pollen-feeding species (all belonging to the genera Heliconius and Laparus) do not have structures exclusive to them. However, in comparison with non-pollen-feeding Heliconiiti, the pollen-feeding species have a significantly longer proboscis without elongation of the tip-region ; the bristle-shaped sensilla trichodea were found to be significantly more numerous and longer on the proximal and mid-region of the proboscis, while the sensilla of the tip-region are significantly shorter. In addition to these proboscis features, the labial palpi were shorter in the pollen-feeding species, which is likewise possibly associated with pollen-feeding behavior. The biological role of these features is discussed and the evolution of this unique feeding behavior among Lepidoptera is considered in the context of the phylogenetic relationships among genera of Heliconiini.     

A new type of gastropod proboscis: the foregut of Hastula bacillus (Gastropoda: Terebridae)

Hastula bacillus (Deshayes) is a small terebrid gastropod which inhabits sandy surf beaches in southern Thailand, where it feeds upon spionid polychaetes. It possesses a foregut anatomy unlike that of any other gastropod. An elongate arborescent muscular organ, known as the accessory proboscis structure, is extended through the mouth during foraging. When retracted, it is folded into an 's' shape in the permanent rhynchodeum. The accessory proboscis structure bears numerous tufts of short, stiff cilia which are associated with pairs or triplets of dome-like structures. It is suggested that the structures may be chemosensory and concerned with prey location. Hastula bacillus also possesses a retractable labial tube, a long proboscis and buccal tube, dart-shaped radular teeth, an odontophore, an accessory salivary gland, a pair of salivary glands and a well-developed venom gland with muscular bulb. A comparison with other terebrid species suggests that H. bacillus is the most plesiomorphic taxon yet described from the family.     

Simultaneous Recording of Calcium Signals from Identified Neurons and Feeding Behavior of Drosophila melanogaster

To study neuronal networks in terms of their function in behavior, we must analyze how neurons operate when each behavioral pattern is generated. Thus, simultaneous recordings of neuronal activity and behavior are essential to correlate brain activity to behavior. For such behavioral analyses, the fruit fly, Drosophila melanogaster, allows us to incorporate genetically encoded calcium indicators such as GCaMP¹, to monitor neuronal activity, and to use sophisticated genetic manipulations for optogenetic or thermogenetic techniques to specifically activate identified neurons^2-5. Use of a thermogenetic technique has led us to find critical neurons for feeding behavior (Flood et al., under revision). As a main part of feeding behavior, a Drosophila adult extends its proboscis for feeding⁶ (proboscis extension response; PER), responding to a sweet stimulus from sensory cells on its proboscis or tarsi. Combining the protocol for PER⁷ with a calcium imaging technique⁸ using GCaMP3.0^{1, 9}, I have established an experimental system, where we can monitor activity of neurons in the feeding center – the suboesophageal ganglion (SOG), simultaneously with behavioral observation of the proboscis. I have designed an apparatus ("Fly brain Live Imaging and Electrophysiology Stage": "FLIES") to accommodate a Drosophila adult, allowing its proboscis to freely move while its brain is exposed to the bath for Ca²⁺ imaging through a water immersion lens. The FLIES is also appropriate for many types of live experiments on fly brains such as electrophysiological recording or time lapse imaging of synaptic morphology. Because the results from live imaging can be directly correlated with the simultaneous PER behavior, this methodology can provide an excellent experimental system to study information processing of neuronal networks, and how this cellular activity is coupled to plastic processes and memory.     

Effects of age and blood sugar levels on the proboscis extension of the blow fly Phormia regina

In some insects the proboscis is extended to imbibe a sugar solution if the concentration of sugar applied to the chemosensilla exceeds the behavioural threshold value. Recently, I found a reversal of the threshold values of this "proboscis extension reflex" (PER) in the blow fly (Phormia regina M.) for glucose and fructose. It depended on maturation and physiological conditions, both of which are explicable in terms of changing concentration of haemolymph trehalose. The direct injection of trehalose into the fly haemocoele brought about a dramatic shift of the threshold values of PER measured on tarsi or labellar sensilla, suggesting a strong dependence of PER on the blood sugar level. Using the tip-recording method, the dose-response (impulse frequency) curves for glucose and fructose were obtained on individual largest labellar chemosensilla. The curves for glucose and fructose crossed at one point because the former had a steeper gradient and higher maximum response than the latter. Injection experiments with trehalose were also carried out to test for changes in gustatory response. The shifting of the behavioural dose-response curves for glucose and fructose two hours after injection of 1 M trehalose (2 μl) into the haemocoele of the fly was associated with significant reduction in responsiveness of labellar chemosensilla to glucose, but less so to fructose. No change in responsiveness was found following injection of mannose. A hypothesis to explain the reversal relation of the PER thresholds, based on a shift in the firing rate in gustatory sensilla and possibly also interneurons, is discussed.     

Paleoneurological evidence against a proboscis in the sauropod dinosaur Diplodocus

The dinosaur Diplodocus has a single, relatively large external bony narial orifice that is positioned far back between the orbits. In some mammals, such as elephants and tapirs, the caudal position of the narial opening is associated with a proboscis, so it has been suggested that Diplodocus possibly also had a trunk. In elephants, the facial nerve is large as it emerges from the brain. A branch of this nerve and a branch of the trigeminal nerve unite to form the proboscidial nerve that supplies the muscles of the powerful and complex motor system of the trunk. In contrast to the situation in modern elephants, the absolute as well as the relatively small size of the facial nerve in Diplodocus (deduced from an endocranial cast) indicates that there is no paleoneuroanatomical evidence for the presence of an elephant-like proboscis in this genus.