Examination of seven specimens of an undescribed species of bamboo shark (Orectolobiformes: Hemiscylliidae), currently referred to as Chiloscyllium sp. 1, from Sri Lanka yielded three new species of 'tetraphyllidean' cestodes, one each in the genera Carpobothrium Shipley et Hornell, 1906, Spiniloculus Southwell, 1925, and Yorkeria Southwell, 1927. Carpobothrium marjorieae Caira, Otto et Jensen sp. n. differs from its three valid congeners in total length, number of testes, and size of the apical sucker of its anterior bothridial flap. Like Carpobothrium eleanorae Koontz et Caira, 2016 it possesses spherical eggs with highly elongate bipolar filaments, but its eggs are conspicuously larger than those of the latter species. Spiniloculus akshayi Caira, Otto et Jensen sp. n. can be distinguished from its five congeners in total length and number of proglottids. Yorkeria sachiniae Caira, Otto et Jensen sp. n. differs from its 16 congeners in number of proglottids and testes, total length, terminal proglottid, cirrus sac, and cephalic peduncle length, hook size, genital pore position, and bothridial shape. The eggs of Y. sachiniae Caira, Otto et Jensen sp. n. are spindle-shaped and bear a single long, polar filament. All three species were found to exhibit microthrix patterns on their scolices like those of the majority of their congeners that have been examined to date with scanning electron microscopy. Microtriches on the distal surfaces of the bothridial pouches of a species of Carpobothrium were characterised for the first time; C. marjorieae Caira, Otto et Jensen sp. n. was found to possess a modified form of gladiate spinithrix on this surface. Among the seven members of the genus, this is the first species of Chiloscyllium Müller et Henle that has been found to host representatives of all three of these 'tetraphyllidean' genera. However, unlike most of its congeners, a representative of the non-hooked genus Scyphophyllidium Woodland, 1927 was not found infecting Chiloscyllium sp. 1.
- MeSH
- Cestoda * anatomy & histology classification isolation & purification MeSH
- Cestode Infections veterinary MeSH
- Classification MeSH
- Microscopy, Electron, Scanning MeSH
- Fish Diseases parasitology MeSH
- Testis anatomy & histology MeSH
- Sharks parasitology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Sri Lanka MeSH
The At-Hook Motif Nuclear Localized Protein (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 is involved in regulation of the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from a decreased LRP initiation. The over-expression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. AHL18 is thus involved in the formation of lateral roots at both LRP initiation and their later development. We conclude that AHL18 participates in modulation of root system architecture through regulation of root apical meristem activity, lateral root initiation and emergence; these correspond well with expression pattern of AHL18.
- MeSH
- Arabidopsis genetics growth & development metabolism MeSH
- AT-Hook Motifs MeSH
- DNA-Binding Proteins chemistry genetics metabolism MeSH
- Plant Roots genetics growth & development metabolism MeSH
- Mutation MeSH
- Arabidopsis Proteins chemistry genetics metabolism MeSH
- Gene Expression Regulation, Plant MeSH
- Gene Expression Regulation, Developmental MeSH
- Publication type
- Journal Article MeSH
Transmission electron microscopy (TEM) was used to study the ultrastructure of the uterus and egg morphology in the enigmatic bothriocephalidean tapeworm Tetracampos ciliotheca. The uterine wall, underlain by well-developed muscle bundles, consists of a syncytial epithelium which is characterized by the abundance of free ribosomes, mitochondria and cisternae of granular endoplasmic reticulum (GER). On the apical surface of the uterine epithelium, there is an abundant network of cytoplasmic microlamellae projecting into the uterine lumen. The lumen is filled with freely lying eggs which are located close to the uterine wall but do not contact with the microlamellae of the uterine epithelium. The developed eggs possess an oncosphere surrounded by four envelopes: (1) a thin egg shell; (2) an outer envelope; (3) a syncytial, ciliated inner envelope; and (4) the oncospheral membrane. The mature hexacanth is armed with three pairs of oncospheral hooks, as well as somatic and hook muscles and five types of cells (1) binucleated subtegumental cell, (2) somatic cells, (3) penetration gland cells, (4) nerve cells and (5) germinative cells. Considering the relative scarcity of descriptive and comparative studies on the ultrastructure of the uterus and egg morphology in the order Bothriocephalidea, we concluded that Tet. ciliotheca displays a unique type of egg development. Based on these results, we discuss plausible ideas relating to the function of these structures for consideration in future studies.
- MeSH
- Cestoda physiology ultrastructure MeSH
- Cestode Infections parasitology veterinary MeSH
- Larva ultrastructure MeSH
- Fish Diseases parasitology MeSH
- Ovum ultrastructure MeSH
- Catfishes parasitology MeSH
- Microscopy, Electron, Transmission MeSH
- Uterus ultrastructure MeSH
- Animals MeSH
- Check Tag
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The apical hook is a transiently formed structure that plays a protective role when the germinating seedling penetrates through the soil towards the surface. Crucial for proper bending is the local auxin maxima, which defines the concave (inner) side of the hook curvature. As no sign of asymmetric auxin distribution has been reported in embryonic hypocotyls prior to hook formation, the question of how auxin asymmetry is established in the early phases of seedling germination remains largely unanswered. Here, we analyzed the auxin distribution and expression of PIN auxin efflux carriers from early phases of germination, and show that bending of the root in response to gravity is the crucial initial cue that governs the hypocotyl bending required for apical hook formation. Importantly, polar auxin transport machinery is established gradually after germination starts as a result of tight root-hypocotyl interaction and a proper balance between abscisic acid and gibberellins.This article has an associated 'The people behind the papers' interview.
- MeSH
- Arabidopsis MeSH
- Plants, Genetically Modified MeSH
- Gibberellins metabolism MeSH
- Hypocotyl growth & development MeSH
- Germination physiology MeSH
- Plant Roots growth & development MeSH
- Abscisic Acid metabolism MeSH
- Indoleacetic Acids metabolism MeSH
- Meristem growth & development MeSH
- Gravity Sensing physiology MeSH
- Arabidopsis Proteins metabolism MeSH
- Gene Expression Regulation, Plant MeSH
- Plant Growth Regulators metabolism MeSH
- Seedlings growth & development MeSH
- Gene Expression Regulation, Developmental MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Auxin phytohormones control most aspects of plant development through a complex and interconnected signaling network. In the presence of auxin, AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors are targeted for degradation by the SKP1-CULLIN1-F-BOX (SCF) ubiquitin-protein ligases containing TRANSPORT INHIBITOR RESISTANT 1/AUXIN SIGNALING F-BOX (TIR1/AFB). CULLIN1-neddylation is required for SCFTIR1/AFB functionality, as exemplified by mutants deficient in the NEDD8-activating enzyme subunit AUXIN-RESISTANT 1 (AXR1). Here, we report a chemical biology screen that identifies small molecules requiring AXR1 to modulate plant development. We selected four molecules of interest, RubNeddin 1 to 4 (RN1 to -4), among which RN3 and RN4 trigger selective auxin responses at transcriptional, biochemical, and morphological levels. This selective activity is explained by their ability to consistently promote the interaction between TIR1 and a specific subset of AUX/IAA proteins, stimulating the degradation of particular AUX/IAA combinations. Finally, we performed a genetic screen using RN4, the RN with the greatest potential for dissecting auxin perception, which revealed that the chromatin remodeling ATPase BRAHMA is implicated in auxin-mediated apical hook development. These results demonstrate the power of selective auxin agonists to dissect auxin perception for plant developmental functions, as well as offering opportunities to discover new molecular players involved in auxin responses.
- MeSH
- Arabidopsis genetics metabolism MeSH
- F-Box Proteins metabolism MeSH
- Transcription, Genetic drug effects MeSH
- Plants, Genetically Modified genetics MeSH
- Indoleacetic Acids metabolism MeSH
- NEDD8 Protein genetics MeSH
- SKP Cullin F-Box Protein Ligases metabolism MeSH
- Arabidopsis Proteins genetics metabolism MeSH
- Proteolysis * MeSH
- Receptors, Cell Surface metabolism MeSH
- Gene Expression Regulation, Plant MeSH
- Plant Growth Regulators genetics metabolism MeSH
- Seedlings metabolism MeSH
- Signal Transduction MeSH
- Transcription Factors metabolism MeSH
- Plant Development genetics physiology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Plant hormones through signaling networks mutually regulate several signaling and metabolic systems essential for both plant development and plant responses to different environmental stresses. Extensive research has enabled the main effects of all known phytohormones classes to be identified. Therefore, it is now possible to investigate the interesting topic of plant hormonal crosstalk more fully. In this review, we focus on the role of brassinosteroids and ethylene during plant growth and development especially flowering, ripening of fruits, apical hook development, and root and shoot growth. As well as it summarizes their interaction during various abiotic stress conditions.
A very small adult specimen of symbiotic palaemonid shrimp collected from Kavieng Lagoon, N.W. New Ireland Island, Papua New Guinea, is described as a new genus and species. Due to the slender subcylindrical body, reduced rostrum, elongated eyes and distolaterally produced uropodal exopods, the new species is somewhat similar to shrimps of the endosymbiotic sponge genus Nippontonia. Both second pereiopods are lost, but the specimen is unique by its bidentate scaphocerites, an apical corona of spiniform teeth on the mandibular molar process, five posterior telson cuspidate setae from which the median and intermediate ones are long, hooked, and the broadly spoon-like dactyli of the first pereiopods chelae with marginal pectination. Based on those characters, the new genus is without parallel among all symbiotic palaemonid shrimps. Its close phylogenetic relationship to the spongobiotic genera Nippontonia, Onycocaridella, and Thaumastocaris, is also confirmed by molecular comparison.
- MeSH
- Animal Structures MeSH
- Decapoda MeSH
- Phylogeny * MeSH
- Islands MeSH
- Palaemonidae * MeSH
- Animal Distribution MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Islands MeSH
- Papua New Guinea MeSH
Regobothrium microhamulinum n. gen. and n. sp. (Bothriocephalidea: Bothriocephalidae) is proposed to accommodate a new cestode from flatfish Catathyridium jenynsii (Chabanaud, 1922) (Pleuronectiformes: Acharidae; type host) and another 3 freshwater fishes of the orders Characiformes, Cyprinodontiformes, and Siluriformes in the Neotropical Region. The new genus is placed in the Bothriocephalidae because it possesses medioventral uterine and mediodorsal genital pores and a follicular vitellarium. Regobothrium n. gen. is characterized by possessing a tiny, slightly subovate scolex narrower than the strobila, with an apical disc armed with 2 semicircles of 15-17 tiny hooks in each and an acraspedote strobila. Regobothrium n. gen. differs from all bothriocephalid cestodes that have a scolex armed with hooks by their small size (maximum length less than 20 μm) and a triangular shape with the basal part (handle or basal plate) shorter than the distal coniform part (blade). In the other hooked bothriocephalids, hooks have a longer handle than a blade. Regobothrium microhamulinum n. gen. and n. sp. is the third bothriocephalidean cestode described from freshwater teleosts in South America but the first out of Patagonia. Molecular phylogenetics consider Regobothrium as a member of a lineage consisting of (up to now exclusively) freshwater bothriocephalids from the Ethiopian biogeographic region, thus indicating Gondwanan relationship.
- MeSH
- Cestoda anatomy & histology classification ultrastructure MeSH
- Characiformes parasitology MeSH
- Cyprinodontiformes parasitology MeSH
- Phylogeny MeSH
- Microscopy, Electron, Scanning MeSH
- Fish Diseases parasitology MeSH
- Flatfishes parasitology MeSH
- Fresh Water MeSH
- Catfishes parasitology MeSH
- Tropical Climate MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Brazil MeSH
- Ethiopia MeSH
- South America MeSH
Two new species of two genera of the order Diphyllidea van Beneden in Carus, 1863, Halysioncum Caira, Marques, Jensen, Kuchta et Ivanov, 2013 and Echinobothrium van Beneden, 1849 sensu stricto are described from Aetomylaeus cf. nichoffi (Bloch et Schneider) off the Iranian coast of the Persian Gulf. Halysioncum kishiense sp. n. differs from all other congeners in the number of apical hooks with the exception of H. hoffmanorum (Tyler, 2001) and H. pigmentatum (Ostrowski de Núñez, 1971). Halysioncum kishiense sp. n. can be easily differentiated from H. hoffmanorum and H. pigmentatum by the number of hooklets and testis numbers. Echinobothrium parsadrayaiense sp. n. is differentiated from all its congeners except for E. acanthinophyllum Rees, 1961 by its hook formula. The number of spines per column on the cephalic peduncle, the number of testes and possession of a thick-walled rather than thin-walled vagina distinguish E. parsadrayaiense sp. n. from E. acanthinophyllum. To date, with these two new species, five species of Diphyllidea have been reported from the Persian Gulf.
- MeSH
- Cestoda classification ultrastructure MeSH
- Cestode Infections epidemiology parasitology MeSH
- Fish Diseases epidemiology parasitology MeSH
- Skates, Fish MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Indian Ocean MeSH
The type species of the genus Glossocercus Chandler, 1935, G. cyprinodontis Chandler, 1935, was described as metacestode (larval stage) from the mesentery of the sheepshead minnow fish (Cyprinodon variegatus Lacépède) from Galveston Bay, Texas. The description was based on the morphology of the rostellar hooks; however, the features of the internal morphology of the proglottides could no be provided. In the present study we describe for the first time the features of the adult G. cyprinodontis from the intestine of Pelecanus occidentalis Linnaeus, Nycticorax nycticorax Linnaeus and Egretta rufescens Gmelin in Mexico. Glossocercus cyprinodontis possesses similar strobilar morphology with the two other congeneric species, both distributed in the Neartic and Neotropical regions, i.e. Glossocercus caribaensis (Rysavy et Macko, 1971) and Glossocercus auritus (Rudolphi, 1819). However, G. cyprinodontis differs mainly in the shape of the rostellar hooks (those of G. cyprinodontis possess the handle and the guard strongly sclerified compared to those of G. auritus and G. caribaensis) and their size (total length of 175-203 microm in G. cyprinodontis compared to 189-211 microm in G. caribaensis and 220-285 microm in G. auritus). Generic diagnosis of Glossocercus is emended: rostellar hooks in two rows with ten hooks of different shape and length in each, scolex large and globular, proglottides craspedote, wider than long, genital pores irregularly alternating, vagina transverse, surrounded by epithelial cells, ventral to cirrus-sac, uterus bar-shaped in mature proglottides, occupies all space between osmoregulatory ducts with eggs in gravid proglottides, ovary lobed in middle of proglottis, cirrus-sac elongate, between osmoregulatory canals, cirrus armed with spinitriches and apical tuft of slender spinitriches.
- MeSH
- Cestoda anatomy & histology classification MeSH
- Cestode Infections epidemiology parasitology veterinary MeSH
- Species Specificity MeSH
- Bird Diseases parasitology MeSH
- Birds MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Mexico MeSH
