The apical pore fibrous complex: a new cytological feature of some dinoflagellates

PROTOPLASMA ◽  
1987 ◽  
Vol 137 (1) ◽  
pp. 65-69 ◽  
Author(s):  
K. R. Roberts ◽  
P. Timpano ◽  
Ann E. Montegut
Keyword(s):  
Cytological Feature ◽  
Apical Pore

Comparative ultrastructural analysis of mycorrhizal associations

1983 ◽  
Vol 61 (3) ◽  
pp. 917-943 ◽  
Author(s):  
Silvano Scannerini ◽  
Paola Bonfante-Fasolo
Keyword(s):  
Electron Microscopy ◽  
Surface Area ◽  
Ultrastructural Analysis ◽  
Nutrient Transfer ◽  
Cytological Feature ◽  
Symbiotic Interactions ◽  
Mycorrhizal Associations ◽  
Host Pathogen ◽  
Bacterial Associations ◽  
Functional Mechanisms

Electron microscopy is a powerful tool in understanding functional mechanisms in symbiosis (i.e., recognition and transfer of nutrients between partners), but mycorrhizal associations are not yet so well known as host–pathogen and host – mutualistic bacterial associations. However, the study of mycorrhizal ultrastructure has provided some interesting information. In fact unknown symbionts can be recognized with electron microscopy and mycorrhizae can be classified according to a sequence linking intercellular and intracellular interactions between host and fungus. General conclusions can be drawn from this ultrastructural sequence. (i) The most significant cytological feature in mycorrhizae is the presence of an interface through which partners communicate along a vast surface area. This is the key area for symbiotic interactions (both recognition and nutrient transfer) and can vary a great deal mostly in intracellular interactions. (ii) The ultracytochemical aspects of those interfaces, mostly as regards the components of the interfacial matrix, appear quite different from those of host–pathogen associations and suggest a compatibility mechanism. (iii) As regards the transfer of nutrients, even though it has been claimed that transfer of nutrient in all intracellular interactions is achieved by a digestion mechanism of the fungus by the host, available ultrastructural data are not consistent with this hypothesis.

Miconia renatogoldenbergii (Miconieae, Melastomataceae), a new species from savanna enclaves in southern Amazonia, Brazil

Phytotaxa ◽  
2017 ◽  
Vol 298 (2) ◽  
pp. 187
Author(s):  
JULIA MEIRELLES ◽  
LUCAS F. BACCI
Keyword(s):  
New Species ◽  
Wide Distribution ◽  
Forest Understory ◽  
Abaxial Surface ◽  
Mato Grosso ◽  
Leaf Apex ◽  
Apical Pore ◽  
Southern Amazonia ◽  
Amazonian Region ◽  
A New Species

A new species of Miconia section Miconia, subsection Seriatiflorae from the Brazilian Amazonian region is described. Miconia renatogoldenbergii has a wide distribution in areas of savanna and forest understory in the states of Pará, Mato Grosso and Rondônia. It is similar to M. punctata as both species have chartaceous leaves with rusty lepidote indument on the abaxial surface. The new species can be distinguished by its mucronate leaf apex, a thyrse with short scorpioid branches, and subulate anthers, with round apex, dehiscent through an apical pore and with cordate connective appendages.

Ultrastructural studies of ascospore liberation in Pyronema domesticum

1977 ◽  
Vol 55 (19) ◽  
pp. 2544-2549 ◽  
Author(s):  
Ching-Yuan Hung
Keyword(s):  
Single Unit ◽  
Spore Wall ◽  
Main Body ◽  
Large Vacuole ◽  
Ultrastructural Studies ◽  
Apical Pore ◽  
Total Disappearance

Ascospores of Pyronema domesticum contain three distinct spore wall layers. The liberation of ascospores presumably commences immediately after the three spore wall layers are formed. This is evidenced by the fact that vesiculation of the investing membrane was observed at the time when three wall layers could be distinguished. Vesiculation continues until the total disappearance of the perispore. Concurrently the epiplasm of the ascus degenerates and converts into a large vacuole within the ascus. Spores are violently ejected through the apical pore that is surrounded by a weakened apical ring. Presumably eight ascospores are discharged at the same time but do not adhere as a single unit. The operculum is generally not hinged to the main body of the ascus and an ascus without ascospores degenerates.

Observations on North American Gomphoneis. III. Gomphoneis septa comb.nov.

1986 ◽  
Vol 64 (11) ◽  
pp. 2764-2768 ◽  
Author(s):  
J. P. Kociolek ◽  
E. F. Stoermer ◽  
L. L. Bahls
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
North American ◽  
Size Range ◽  
Taxonomic Position ◽  
Apical Pore ◽  
Close Relationship ◽  
Ultrastructural Characteristics ◽  
Scanning Electron

The valvar ultrastructure of the diatom Gomphonema septum Mogh. was investigated with scanning electron microscopy and is discussed with regard to the taxonomic position of this species. Ultrastructural features include striae composed of double rows of puncta, presence of a narrow axial plate which is responsible for the image of longitudinal lines, and apical pore fields composed of pores dissimilar in appearance from the puncta. These and other ultrastructural characteristics point to a close relationship between G. septum and members of the genus Gomphoneis. A transfer of Gomphonema septum to Gomphoneis is proposed. Information supplemental to previous observations on the size range and variability of this species is presented.

Fine structure of aesthetasc chemoreceptors in the crayfish Orconectes propinquus

1986 ◽  
Vol 64 (2) ◽  
pp. 392-399 ◽  
Author(s):  
Ann Jane Tierney ◽  
C. S. Thompson ◽  
D. W. Dunham
Keyword(s):  
Distal Portion ◽  
Main Body ◽  
Decapod Crustaceans ◽  
Orconectes Propinquus ◽  
Outer Sheath ◽  
Apical Pore ◽  
Cell Layers ◽  
Chemical Stimuli ◽  
Sensory Endings ◽  
Sheath Cells

The outer antennular flagella of decapod crustaceans bear chemoreceptive hairs called aesthetascs. In the crayfish Orconectes propinquus these sensilla are located ventrally on the 11–13 most distal segments of the outer flagella. Two clumps of 3–6 aesthetascs occur on each segment, giving a total of approximately 80 aesthetascs per outer flagellum. Aesthetascs are100–150 μm long and about 12 μm in diameter. Each has a single annulation 30 μm from the hair base. The sensilla arise from immovable sockets and are directed distally at a 45° angle to the main body of the antennule. Aesthetascs lack an apical pore. However, the distal portion of each sensillum has thin cuticular walls which are readily penetrated by dye; this is probably the site where chemical stimuli enter. In O. propinquus each aesthetasc is innervated by 40–110 sensory neurons. Each neuron gives rise to a dendrite that branches into two cilia (9 × 2 + 2 structure; 0.15–0.20 μm in diameter). No further branching of outer dendritic segments occurs and thus each aesthetasc contains 80–220 sensory endings. Within the antennule lumen the dendrites are surrounded by two sheath cell layers, an inner layer and an outer layer. The inner sheath cells ascend 50 μm into the aesthetasc lumen; the outer sheath cells terminate at the sensilla bases. The outer dendritic segments gradually taper in diameter and terminate 25 μm from the sensilla tips.

scholarly journals Three new needle-shaped Fragilaria species from Central America and the Tibetan Plateau

Phytotaxa ◽  
2021 ◽  
Vol 479 (1) ◽  
pp. 1-22
Author(s):  
KIM J. KRAHN ◽  
ANJA SCHWARZ ◽  
CARLOS E. WETZEL ◽  
SERGIO COHUO-DURÁN ◽  
GERHARD DAUT ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Specific Conductivity ◽  
Central Area ◽  
High Elevation ◽  
Width Ratio ◽  
Similar Species ◽  
The Tibetan Plateau ◽  
Alkaline Ph ◽  
Apical Pore ◽  
Lake Nam Co

Three new needle-shaped Fragilaria species from freshwater lake Apastepeque in El Salvador (Fragilaria salvadoriana sp. nov., F. maarensis sp. nov.) and subsaline lake Nam Co on the Tibetan Plateau (F. huebeneri sp. nov.) are described and compared based on light and scanning electron microscopy observations and morphometric analyses. Fragilaria salvadoriana sp. nov. is characterized by narrowly linear-lanceolate, sometimes centrally constricted valves, subcapitate to rarely capitate apices, and a distinct, dented appearing central area. Striae are composed of 2−5 occluded areolae. It can be differentiated from similar needle-shaped species by the valve outline, relatively low striae density, and shark fin-shaped spines. Characteristic of F. maarensis sp. nov. are a very narrowly lanceolate valve outline and subcapitate apices. The apical pore field is composed of 2–3 rows of poroids and acute, irregularly oriented spines are present at the junction between valve face and mantle. This taxon is clearly different from other Fragilaria species, displaying a high length-to-width ratio and a low number of areolae per stria. The Tibetan species, F. huebeneri sp. nov., forms long ribbon-like colonies linked together by spatula-shaped spines. Valves have subcapitate apices, a spindle- to needle-shaped outline and an indistinct central area. Striae are alternate and composed of 3–5 areolae per stria. Teratological forms of F. huebeneri sp. nov. were commonly observed in the sediment trap samples. Fragilaria salvadoriana sp. nov. and F. maarensis sp. nov. were found in a warm, tropical crater lake characterized by low conductivity and dissolved oxygen content, medium alkaline pH, and magnesium-calcium-bicarbonate-rich waters. Fragilaria huebeneri sp. nov. was frequent in a large, high elevation lake with increased specific conductivity, alkaline pH and sodium-bicarbonate-rich waters. The new species are compared to morphologically similar species from the genus Fragilaria Lyngbye and ecological preferences are discussed.

scholarly journals New and poorly known “araphid” diatom species (Bacillariophyta) from regions near Lake Titicaca, South America and a discussion on the continued use of morphological characters in “araphid” diatom taxonomy

PhytoKeys ◽  
2021 ◽  
Vol 187 ◽  
pp. 23-70
Author(s):  
Eduardo A. Morales ◽  
Carlos E. Wetzel ◽  
Luc Ector
Keyword(s):  
Morphological Characters ◽  
Ecological Change ◽  
Lake Titicaca ◽  
Molecular Approaches ◽  
The Andes ◽  
Apical Pore ◽  
Andean Altiplano ◽  
Continued Use ◽  
Species Distinction ◽  
Diatom Taxonomy

Based on two Andean Altiplano samples and on light and scanning electron microscopy analyses, we present six new species of “araphid” diatoms in the genus Pseudostaurosira, P. aedessp. nov., P. frankenaesp. nov., P. heteropolarissp. nov., P. oblongasp. nov., P. occultasp. nov., and P. pulchrasp. nov. Additional data are provided for four other known taxa, Nanofrustulum cataractarum, N. rarissimum, P. sajamaensis and P. vulpina, the latter species corresponding to a stat. nov. based on a variety of P. laucensis. Each taxon is described morphologically and compared with closely related published taxa, using characters such as axial area, virgae, vimines, areolar shape, volae, internal striae depositions, spines, flaps and apical pore fields, which are not usually used for species distinction within the genus. It is our intention that the detailed morphological descriptions of each taxon and the elaborate comparative tables we provide serve as a basis for correction of neo and paleo-databases for the Altiplano to produce a better account of autecological data and ecological change in the region. Some arguments for our continued use of a morphologically based approach are given in the context of rapid environmental degradation in the Andes and the difficulties in applying molecular approaches in countries such as Bolivia.

scholarly journals Seven new Neocallimastigomycota genera from fecal samples of wild, zoo-housed, and domesticated herbivores: Description ofGhazallomyces constrictusgen. nov., sp. nov.,Aklioshbomyces papillarumgen. nov., sp. nov.,Agriosomyces longusgen. nov., sp. nov.,Capellomyces foraminisgen. nov., sp. nov. andCapellomyces elongatussp. nov.,Joblinomyces apicalisgen. nov., sp. nov.,Khoyollomyces ramosusgen. nov., sp. nov., andTahromyces munnarensisgen. nov., sp. nov

2019 ◽  
Author(s):  
Radwa A. Hanafy ◽  
Vikram B. Lanjekar ◽  
Prashant K. Dhakephalkar ◽  
Tony M. Callaghan ◽  
Sumit S. Dagar ◽  
...  
Keyword(s):  
Indian States ◽  
Fecal Samples ◽  
Boer Goat ◽  
Zoospore Release ◽  
Apical Pore ◽  
The Us ◽  
Culture Independent ◽  
Microscopic Features ◽  
Axis Deer ◽  
Sporangial Wall

ABSTRACTWe isolated and characterized sixty-five anaerobic gut fungi (AGF, Neocallimastigomycota) strains from fecal samples of five wild (W), one zoo-housed (Z), and three domesticated (D) herbivores in the US states of Texas (TX) and Oklahoma (OK), Wales (WA), and the Indian states of Kerala (KE) and Haryana (HA). Phylogenetic assessment based on D1-D2 region of the large rRNA subunit (LSU) identified seven distinct lineages, with strains recovered from Axis Deer (W-TX) clustering within theOrpinomyces-Neocallimastix-Pecoramyces-Feramycesclade; Boer Goat-domesticated Goat strains (W-TX, D-KE) clustering within theOontomyces-Anaeromyces-Liebetanzomycesclade; and domesticated Goat and Sheep strains (D-HA) as well as Nilgiri Tahr strains (W-KE) forming two distinct clades associated with genusBuwchfawromyces. The remaining three lineages, represented by strains recovered from Mouflon-Boer Goat (W-TX), White Tailed Deer (W-OK), and Zebra-Horse (Z-OK, and D-WA), displayed no specific suprageneric affiliation. All strains displayed monocentric thalli and produced mono/uniflagellate zoospores with the exception of Axis Deer strains, which produced polyflagellate zoospores. Isolates displayed multiple interesting microscopic features including sporangia with tightly constricted necks and fine septa at the base (Axis Deer), papillated and pseudo-intercalary sporangia (White-Tailed Deer), swollen sporangiophores and zoospores with long flagella (Mouflon-Boer Goat), zoospore release through an apical pore followed by either sporangial wall collapse (Axis Deer and Boer Goat-domesticated Goat) or sporangial wall remaining intact after discharge (Zebra-Horse), multi-sporangiated thalli with branched sporangiophores (Zebra-Horse), and short sporangiophores with subsporangial swellings (Nilgiri Tahr). Internal transcribed spacer-1 region (ITS-1) sequence analysis indicated that Zebra-Horse strains are representatives of the AL1 lineage, frequently encountered in culture-independent surveys of the alimentary tract and fecal samples from hindgut fermenters. The other six lineages, five of which were isolated from wild herbivores, have not been previously encountered in such surveys. Our results significantly expand the genus level diversity within the Neocallimastigomycota, and strongly suggest that wild herbivores represent a yet-untapped reservoir of AGF diversity. We propose the creation of seven novel genera and eight novel Neocallimastigomycota species to accommodate these strains, for which we propose the namesAgriosomyces longus(Mouflon and wild Boer Goat),Aklioshbomyces papillarum(White tailed Deer),Capellomyces foraminis(wild Boar Goat) andC. elongatus(domesticated Goat),Ghazallomyces constrictus(Axis Deer),Joblinomyces apicalis(domesticated Goat and Sheep),Khoyollomyces ramosus(Zebra-Horse), andTahromyces munnarensis(Nilgiri Tahr). The type species are strains Axs-31, WT-2, MS-4, BGB-11, GFKJa1916, GFH683, ZS-33, and TDFKJa193, respectively.

A new species of Cymbella (Bacillariophyceae, Cymbellaceae) from the Pavana River, Western Ghats, India

Phytotaxa ◽  
2019 ◽  
Vol 395 (3) ◽  
pp. 209 ◽  
Author(s):  
ANBUKKARASU VIGNESHWARAN ◽  
MAXIM S. KULIKOVSKIY ◽  
ANTON GLUSHCHENKO ◽  
JOHN PATRICK KOCIOLEK ◽  
BALASUBRAMANIAN KARTHICK
Keyword(s):  
New Species ◽  
Western Ghats ◽  
Species Description ◽  
Diatom Species ◽  
Diatom Flora ◽  
Apical Pore ◽  
Lotic System ◽  
New Species Description ◽  
A New Species

New diatom species from the genus Cymbella is described, Cymbella pavanaensis from the Pavana River situated in Pimpri-Chinchwad, Pune, Maharashtra, India. The new species description is based on detailed LM and SEM morphological observations. Comparison of the new species with similar, previously-described taxa is made. C. pavanaensis belongs to a group of small-celled species of the genus, which lack differentiated, rounded porelli comprising the apical pore fields. This taxon is reported from a moderately to the highly-polluted urban lotic system, which signifies that even the diatom flora of easily accessible habitats of India is yet to be fully documented.

scholarly journals Kliopsyllus schminkei sp. n. (Copepoda, Harpacticoida, Paramesochridae) — a new copepod from the southeast Atlantic deep sea (Angola Basin)

Zootaxa ◽  
2009 ◽  
Vol 2096 (1) ◽  
pp. 313-326 ◽  
Author(s):  
GRITTA VEIT-KÖHLER ◽  
JAN DREWES
Keyword(s):  
New Species ◽  
Body Size ◽  
Deep Sea ◽  
The Other ◽  
Whole Body ◽  
Apical Pore ◽  
A New Species

A new species of Kliopsyllus (Paramesochridae) has been collected with a multicorer from the abyssal Angola Basin in 2000 (on the DIVA-1 cruise, RV Meteor 48/1). Kliopsyllus schminkei sp. n. is the second most abundant Kliopsyllus- species in the Angola Basin and raises the number of valid members of the genus to 33. The new species is placed in the genus Kliopsyllus because of its typical segmentation and the setation of the swimming legs. K. schminkei sp. n. is unique within the genus and can be distinguished from the other species by a large apical pore on the P5 baseoendopodal lobes of the male, a length:width ratio of the furcal rami of 9 to 10:1 in both sexes, and an exceptional ratio of the length of the furcal rami to the whole body size of one fourth in the female and one fifth in the male. The new species is one of the four deep-sea Kliopsyllus-species described until now.

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