Lateral jaw muscles of Elachistodon westermanni Reinhardt (Reptilia: Serpentes)

1976 ◽  
Vol 54 (4) ◽  
pp. 510-521 ◽  
Author(s):  
Herbert I. Rosenberg ◽  
Carl Gans
Keyword(s):  
Adductor Muscle ◽  
Minor Role ◽  
Jaw Muscles ◽  
Lower Jaw ◽  
Adductor Muscles ◽  
Harderian Glands ◽  
A Minor ◽  
Shift Of Origin ◽  
First Time ◽  
Jaw Musculature

Lateral jaw musculature of the very rare Elachistodon is described for the first time and compared with Dasypeltis. The enormous Harderian glands of both genera and their relationships with adjacent muscles are also described. Myological differences and similarities between Elachistodon, Dasypeltis, and some generalized colubrid snakes are tabulated. The primary myological differences are found in the adductor muscles of the lower jaw. Elachistodon and Dasypeltis have a single, major adductor muscle of the lower jaw, that attaches dorsally along the length of the quadrate and ventrally along the lower jaw. This muscle probably represents a fused medialis and profundus. Both species also have a small superficialis that may play a minor role in elevating the lower jaw. The reduction in size and shift of origin of the adductors is discussed in terms of functional demands associated with egg eating. Morphological similarities indicate that Elachistodon and Dasypeltis are probably related.

scholarly journals Occurrence of L1014F and L1014S mutations in insecticide resistant Culex quinquefasciatus from filariasis endemic districts of West Bengal, India

2022 ◽  
Vol 16 (1) ◽  
pp. e0010000
Author(s):  
Priyanka Rai ◽  
Dhiraj Saha
Keyword(s):  
Culex Quinquefasciatus ◽  
West Bengal ◽  
Economic Status ◽  
Minor Role ◽  
Resistance Development ◽  
Vector Population ◽  
A Minor ◽  
First Time

Introduction Lymphatic filariasis causes long term morbidity and hampers the socio-economic status. Apart from the available treatments and medication, control of vector population Culex quinquefasciatus Say through the use of chemical insecticides is a widely applied strategy. However, the unrestrained application of these insecticides over many decades has led to resistance development in the vectors. Methods In order to determine the insecticide susceptibility/resistance status of Cx. quinquefasciatus from two filariasis endemic districts of West Bengal, India, wild mosquito populations were collected and assayed against six different insecticides and presence of L1014F; L1014S kdr mutations in the voltage-gated sodium channel gene was also screened along with the use of synergists to evaluate the role of major detoxifying enzymes in resistance development. Results The collected mosquito populations showed severe resistance to insecticides and the two synergists used–PBO (piperonyl butoxide) and TPP (triphenyl phosphate), were unable to restore the susceptibility status of the vector thereupon pointing towards a minor role of metabolic enzymes. kdr mutations were present in the studied populations in varying percent with higher L1014F frequency indicating its association with the observed resistance to pyrethroids and DDT. This study reports L1014S mutation in Cx. quinquefasciatus for the first time.

scholarly journals Jaw musculature of Cyclarhis gujanensis (Aves: Vireonidae)

2015 ◽  
Vol 75 (3) ◽  
pp. 655-661 ◽  
Author(s):  
DM. Previatto ◽  
SR. Posso
Keyword(s):  
Functional Anatomy ◽  
Feeding Apparatus ◽  
Temporal Fossa ◽  
Jaw Muscles ◽  
Number Of Components ◽  
Caudal Portion ◽  
Jaw Apparatus ◽  
Adductor Muscles ◽  
Anatomical Knowledge ◽  
Jaw Musculature

AbstractCyclarhis gujanensis is a little bird which feeds on high number of large preys, such frogs, lizards, snakes, bats and birds. As there are few studies on the cranial anatomy of this species, we aimed to describe the cranial myology to contribute to the anatomical knowledge of this species and to make some assumptions about functional anatomy. Thus, we described the muscles from the jaw apparatus (external and internal adductor muscles, the muscles of the pterygoid system and the depressor muscles of the mandible). The adductor system is the greatest and multipinulated, particularly in its origin in the caudal portion of the temporal fossa. The depressor jaw muscles systems are enlarged with many components in complexity. The most of jaw apparatus muscles are short, but the strength (biting or crushing forces) from short feeding apparatus fibers probably is increased by high number of components and pinnulation. These anatomical aspects of the muscles indicate a considerable force in the jaws, without which C. gujanensis probably could not cut their prey into smaller pieces. However, functional approaches to analysis of forces of the muscle fibers are needed to corroborate / refute the hypotheses mentioned above.

scholarly journals Natural Competence Is a Major Mechanism for Horizontal DNA Transfer in the Oral Pathogen Porphyromonas gingivalis

mBio ◽  
2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Gena D. Tribble ◽  
Todd W. Rigney ◽  
Doan-Hieu V. Dao ◽  
Cindy T. Wong ◽  
Jennifer E. Kerr ◽  
...  
Keyword(s):  
Porphyromonas Gingivalis ◽  
Dna Transfer ◽  
Extracellular Dna ◽  
Minor Role ◽  
Chromosomal Dna ◽  
Natural Competence ◽  
Content Type ◽  
A Minor ◽  
First Time

ABSTRACTPorphyromonas gingivalisis a Gram-negative anaerobe that resides exclusively in the human oral cavity. Long-term colonization byP. gingivalisrequires the bacteria to evade host immune responses while adapting to the changing host physiology and alterations in the composition of the oral microflora. The genetic diversity ofP. gingivalisappears to reflect the variability of its habitat; however, little is known about the molecular mechanisms generating this diversity. Previously, our research group established that chromosomal DNA transfer occurs betweenP. gingivalisstrains. In this study, we examine the role of putative DNA transfer genes in conjugation and transformation and demonstrate that natural competence mediated bycomFis the dominant form of chromosomal DNA transfer, with transfer by a conjugation-like mechanism playing a minor role. Our results reveal that natural competence mechanisms are present in multiple strains ofP. gingivalis, and DNA uptake is not sensitive to DNA source or modification status. Furthermore, extracellular DNA was observed for the first time inP. gingivalisbiofilms and is predicted to be the major DNA source for horizontal transfer and allelic exchange between strains. We propose that exchange of DNA in plaque biofilms by a transformation-like process is of major ecological importance in the survival and persistence ofP. gingivalisin the challenging oral environment.IMPORTANCEP. gingivaliscolonizes the oral cavities of humans worldwide. The long-term persistence of these bacteria can lead to the development of chronic periodontitis and host morbidity associated with tooth loss.P. gingivalisis a genetically diverse species, and this variability is believed to contribute to its successful colonization and survival in diverse human hosts, as well as evasion of host immune defenses and immunization strategies. We establish here that natural competence is the major driving force behindP. gingivalisDNA exchange and that conjugative DNA transfer plays a minor role. Furthermore, we reveal for the first time the presence of extracellular DNA inP. gingivalisbiofilms, which is most likely the source of DNA exchanged between strains within dental plaque. These studies expand our understanding of the mechanisms used by this important member of the human oral flora to transition its relationship with the host from a commensal to a pathogenic relationship.

scholarly journals The Response of Parameterized Orographic Gravity Waves to Rapid Warming over the Tibetan Plateau

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1016
Author(s):  
Runqiu Li ◽  
Xin Xu ◽  
Yuan Wang ◽  
Miguel A. C. Teixeira ◽  
Jianping Tang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Gravity Waves ◽  
Horizontal Wind ◽  
Buoyancy Frequency ◽  
Minor Role ◽  
The Tibetan Plateau ◽  
A Minor ◽  
Increasing Trends ◽  
First Time

Using the ERA-Interim reanalysis during 1979–2017, this work for the first time investigates the climatology and long-term trend of orographic gravity waves (OGWs) in the Tibetan Plateau (TP). The linkage between the trends of OGWs and the rapid warming over the TP is also studied. Climatologically, the most prominent surface wave momentum flux (SWMF) of OGWs occurs in the western and southeastern TP, while it is weak in the central TP. The SWMF is stronger in winter and spring than in autumn and summer. Overall, the mean SWMF over the TP experienced a weak decreasing trend. The decrease of SWMF mainly took place in the western and southeastern TP in spring. However, increasing trends were found in the central TP in winter. Changes of SWMF are mainly caused by the changes of horizontal wind near the surface, while buoyancy frequency and air density play a minor role. In response to the inhomogeneous warming over the TP, the surface winds were adjusted through thermal wind balance. In spring (winter), the most remarkable warming occurred in the northern (southern) TP, which reduced (enhanced) the meridional temperature gradient across the plateau, and thus led to a deceleration (acceleration) of the horizontal wind.

Cranial morphology of the Loxommatidae (Amphibia: Labyrinthodontia)

1977 ◽  
Vol 280 (971) ◽  
pp. 29-101 ◽  
Keyword(s):  
Functional Morphology ◽  
Cranial Morphology ◽  
Additional Material ◽  
Jaw Muscles ◽  
Skull Shape ◽  
New Family ◽  
The Family ◽  
Basal Articulation ◽  
First Time ◽  
Jaw Musculature

The labyrinthodont superfamily Loxommatoidea is now divided into two families. The highly aberrant Spathicephalus is placed in a new family, the Spathicephalidae, to be described elsewhere. The family Loxommatidae is retained for the remaining genera, Loxomma, Megalocephalus and Baphetes . Additional material and further preparation has made possible a redescription of the three loxommatid genera and new skull restorations have been produced for most species. In particular the loxommatid braincase and palatoquadrate are reconstructed for the first time; in many features their structure is more primitive than that hitherto described for any temnospondyl. Since an intertemporal bone is found to be a feature of Baphetes as well as Loxomma , these two genera have been separated on the basis of skull shape and on stratigraphical grounds. A specimen from the Communis zone, Westphalian A, is attributed to Loxomma , as L. rankini sp.nov., while ‘ Loxomma bohemicum ’ has been transferred to the genus Baphetes as B. bohemicus (Fritsch). A further specimen, originally associated with Macrerpeton , has also been referred to this genus as B. lintonensis sp.nov. The skull of Megalocephalus pachycephalus can be described in greater detail than that of any other loxommatid species and thus forms the basis for discussion of the functional morphology. Jaw muscles are reconstructed for this species and it is concluded that the antorbital vacuity, which characterizes the Loxommatoidea, evolved as a bulging hole for a large pterygoideus muscle associated with a piscivorous habit and a kinetic inertial system of jaw closure. Consideration of the mechanics of jaw closure sheds light on a further enigma, i.e. the function of the basipterygoid articulation in the primitive temnospondyl skull. The loxommatid skull is considered divisible into two units. The presence of a specialized cranial joint between the quadrate and quadratojugal allows potential for any movement at the basal articulation to be accommodated in the main at this site. It is suggested that the system described for loxommatids represents an alternative design to the mobile cheek region of anthracosaurs and that the articulations represent zones of elasticity, which accommodate the stresses on the skull caused by a powerful jaw musculature.

Делоо«Брауншвейгскомсемействе»

2019 ◽  
pp. 194-223
Author(s):  
L.I. Levin
Keyword(s):  
20Th Century ◽  
Minor Role ◽  
Joint Work ◽  
Historical Events ◽  
History Of ◽  
The Creation ◽  
Actual Contribution ◽  
A Minor ◽  
First Time

статья посвящена истории создания рукописи The Brunswick Family, которая впервые основана на обширные архивные материалы освещали жизнь младенца Император Иван VI Антонович, свергнутый в 1741 г. семья. Основными источниками для статьи были следующие: черновик рукописи В. В. Стасова с пометками М. А. Корфа, The Brunswick Family рукопись опубликована под именем Korf в 1993 году, переписка между Стасовым и Корфом и некоторые другие документы. Была предпринята попытка определить, каков был фактический вклад обоих авторы к совместной работе с целью выявления принципиальных различий в их точки зрения и оценки исторических событий и личностей. В 20 веке некоторые историки считали, что Стасов играл второстепенную роль роль и действовал по указанию Корфа (который инициировал создание Рукопись The Brunswick Family, предоставила Стасову доступ к источникам, и кто постоянно редактировал рукопись). Однако, после расследовать различные материалы и история рукописи, что заявление появляется необоснованныйThe article is dedicated to the history of a manuscript The Brunswick Family , which for the first time based on extensive archival materials highlighted the life of the infant Emperor Ivan VI Antonovich, dethroned in 1741, and his family. The main sources for the article were the following: a draft manuscript by V.V. Stasov with M.A. Korfs notes, The Brunswick Family manuscript published under the name of Korf in 1993, the correspondence between Stasov and Korf, and some other documents. An attempt was made to determine what was the actual contribution of both authors to the joint work in order to identify the fundamental differences in their viewwpoints and evaluations of historical events and personalities. In the 20th century, some historians believed that Stasov played a minor role and acted according to Korfs instructions (who initiated the creation of The Brunswick Family manuscript, provided Stasov with access to sources, and who constantly edited the manuscript). However, after investigating of various materials and the history of the manuscript, that statement appears groundless

Direct observation of syringeal muscle function in songbirds and a parrot

2002 ◽  
Vol 205 (1) ◽  
pp. 25-35
Author(s):  
Ole Næsbye Larsen ◽  
Franz Goller
Keyword(s):  
Minor Role ◽  
Tracheal Lumen ◽  
Experimental Conditions ◽  
Cardinalis Cardinalis ◽  
Direct Observations ◽  
Adductor Muscles ◽  
Simultaneous Activation ◽  
Muscle Groups ◽  
A Minor ◽  
Aperture Control

SUMMARYThe role of syringeal muscles in controlling the aperture of the avian vocal organ, the syrinx, was evaluated directly for the first time by observing and filming through an endoscope while electrically stimulating different muscle groups of anaesthetised birds.In songbirds (brown thrashers, Toxostoma rufum, and cardinals, Cardinalis cardinalis), direct observations of the biomechanical effects of contraction largely confirm the functions of the intrinsic syringeal muscles proposed from indirect studies. Contraction of the dorsal muscles, m. syringealis dorsalis (dS) and m. tracheobronchialis dorsalis, constricts the syringeal lumen and thus reduces airflow by adducting connective tissue masses, the medial (ML) and lateral (LL) labia. Activity of the medial portion of the dS appears to affect the position of the ML and, consequently, plays a previously undescribed role in aperture control. Under the experimental conditions used in this study, full constriction of the syringeal lumen could not be achieved by stimulating adductor muscles. Full closure may require simultaneous activation of extrinsic syringeal muscles or the supine positioning of the bird may have exerted excessive tension on the syrinx. Contraction of m. tracheobronchialis ventralis enlarges the syringeal lumen and thus increases airflow by abducting the LL but does not affect the ML. The largest syringeal muscle, m. syringealis ventralis, plays a minor role, if any, in direct aperture control and thus in gating airflow.In parrots (cockatiels, Nymphicus hollandicus), direct observations show that even during quiet respiration the lateral tympaniform membranes (LTMs) are partially adducted into the tracheal lumen to form a narrow slot. Contraction of the superficial intrinsic muscle, m. syringealis superficialis, adducts the LTMs further into the tracheal lumen but does not close the syringeal aperture fully. The intrinsic deep muscle, m. syringealis profundus, abducts the LTMs through cranio-laterad movement of a paired, protruding half-ring. The weakly developed extrinsic m. sternotrachealis seems to increase tension in the ipsilateral LTM but does not move it in or out of the syringeal lumen.

scholarly journals Runaways and shells around the CMa OB1 association

2019 ◽  
Vol 628 ◽  
pp. A44 ◽  
Author(s):  
B. Fernandes ◽  
T. Montmerle ◽  
T. Santos-Silva ◽  
J. Gregorio-Hetem
Keyword(s):  
Star Formation ◽  
Supernova Remnant ◽  
Original Position ◽  
Minor Role ◽  
Star Forming ◽  
Large Shell ◽  
A Minor ◽  
First Time ◽  
Astrometric Data ◽  
Runaway Stars

Context. The origin of the arc-shaped Sh 2-296 nebula is still unclear. Mainly due to its morphology, the nebula has been suggested to be a 0.5 Myr old supernova remnant (SNR) that could be inducing star formation in the CMa OB1 association. This means that the region might be an excellent laboratory for investigating the influence of massive stars on their surroundings. Aims. We aim to show for the first time that the nebula is part of a large shell-like structure, which we have designated the “CMa shell”, enclosing a bubble created by successive supernova (SN) explosions. We identify three runaway stars, associated with bow-shock structures, in the direction of the CMa shell, and we investigate the possibility that they have originated in the center of the shell. Methods. By analyzing images of the CMa OB1 association at several wavelengths, we clearly saw that the Sh 2-296 nebula is in fact part of a large structure that can be approximated by a large elliptical shell (with a diameter of ~60 pc). Using the recent Gaia DR2 astrometric data, we traced back the path of the three runaway stars, in order to determine their original position in the past, with relation to the CMa shell. We also revised the heating and ionization of the Sh 2-296 nebula by comparing the photon budget provided by the O stars in the region with results from radio observations. Results. We find that the runaway stars have likely been ejected from a Trapezium-like progenitor cluster on three successive SN explosions that occurred ~6, ~2 and ~1 Myr ago. We also show that the few late-type O stars in the region cannot explain the ionization of the Sh 2-296 nebula, and that other mechanisms need to be at work. Conclusions. We argue that although we now have evidence for several SNe events in the CMa OB1 association, the SNe probably played a minor role in triggering star formation in these clouds. In contrast, the CMa OB1 association as it is now likely testifies to the last stages of a star-forming region.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

1958 ◽  
Vol 02 (05/06) ◽  
pp. 462-480 ◽  
Author(s):  
Marc Verstraete ◽  
Patricia A. Clark ◽  
Irving S. Wright
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Minor Role ◽  
Rabbit Lung ◽  
Coagulation Mechanism ◽  
Time Test ◽  
The One ◽  
A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

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