apical cells
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2021 ◽  
Vol 9 ◽  
Author(s):  
Xi Fu ◽  
Dan-Feng Bao ◽  
Zong-Long Luo ◽  
Xiu He ◽  
Hong-Yan Su

Pleosporales is the largest order of Dothideomycetes. In recent years, systematics of Pleosporales have undergone considerable revisions. Dictyosporiaceae is one of the newly established families within this order proposed to accommodate holomorphic saprobic Dothideomycetes. Currently 18 genera are recognised in Dictyosporiaceae. The new species, Jalapriya aquaticum sp. nov. and J. apicalivaginatum sp. nov. were collected from freshwater habitats in Gansu and Yunnan Provinces, China, respectively and are introduced, based on morphology and molecular analysis of combined ITS, LSU, SSU and TEF1-α sequence data. We also recovered one fresh collection of Dictyocheirospora vinaya D’souza, Bhat & K.D. Hyde, which is a new record for China. Jalapriya aquaticum differs from extant species of Jalapriya in rows converging at the apex and apical cells with spherical-like appendages. Jalapriya apicalivaginatum differs from extant species of Jalapriya in having the rows of conidia mostly arranged in a plane. The phylogenetic analysis place the new collections within Dictyosporiaceae (Pleosporales). Descriptions and illustrations of Jalapriya aquaticum, J. apicalivaginatum and Dictyocheirospora vinaya are provided. A synopsis of characters of species of Jalapriya is also provided.



2020 ◽  
Vol 52 (6) ◽  
pp. 437-453
Author(s):  
Mikhail P. Zhurbenko ◽  
Yoshihito Ohmura

AbstractFive species of lichenicolous fungi are described as new to science: Buelliella ohmurae Zhurb. & Diederich (on Icmadophila), with a non-granulose epihymenium, not or only slightly enlarged, pale brown apical cells of paraphysoids and 1-septate, smooth ascospores; Catillaria japonica Zhurb. & Hafellner (on Dibaeis and Pseudobaeomyces), with a medium to dark reddish brown epihymenium, exciple and hypothecium, rather frequently branched and anastomosed paraphyses with only slightly enlarged apical cells without a dark cap, and Catillaria-type asci; Cryptodiscus ihlenii Zhurb. (on Dibaeis), with persistently immersed ascomata, non-amyloid asci and hymenium, not or only slightly enlarged apical cells of paraphyses and narrowly obovate, 1-septate ascospores; Llimoniella chilensis Zhurb. (on Dibaeis and a sterile microsquamulose lichen), with a K+ green exciple and epihymenium and aseptate, broadly ellipsoid ascospores; and Stigmidium phyllobaeidis Zhurb., Etayo & Flakus (on apothecial discs of Phyllobaeis), with a hemiamyloid interascal gel, not previously reported in that genus, well-developed, 1‒2(‒4)-celled periphysoids, elongate asci and hyaline, 1-septate ascospores. An undescribed species of Arthonia (on Pseudobaeomyces) is briefly characterized. Sphaerellothecium coniodes is newly reported for Asia. A key to the 32 species of lichenicolous fungi and lichens known to occur on baeomycetoid lichens and Icmadophila is provided.



2020 ◽  
Vol 64 (1) ◽  
pp. 11-18
Author(s):  
S. G. Olukole ◽  
O. M. Coker ◽  
B. O. Oke

AbstractThe epididymis plays an important role in sperm maturation, storage, transport and in the secretion of enzymes and proteins into the tubular lumen. In this study, we examined the histology, microstereology and immunohistochemical localization of alpha smooth muscle (αSMA) in the three regions of the epididymis of the African four-toed hedgehog (Atelerix albiventris). Ten adult males were captured from the wild in Ibadan, Nigeria, between May and October, 2016. The animals were euthanized and the epididymis (caput, corpus and cauda regions) were retrieved and fixed in buffered neutral formalin ahead of the paraffin technique, following standard procedures. The duct of the epididymis was lined by pseudostratified columnar epithelium comprising basal, principal and apical cells as well as intraepithelial lymphocytes in proximity to basal cells. The principal cells, the major cells encountered within the epididymal epithelium of the animal, decreased in population from the caput to the cauda epididymidis while the apical cells were more abundant in the cauda epididymidis. Positive reactions to αSMA were observed in the peritubular muscular coat of the epididymal duct as well as blood vessels across the three regions of the epididymis with the caput and cauda epididymidis showing stronger positive reactions compared to the corpus epididymidis. This study demonstrated that the histology, microstereology as well as the cellular constituents of the epididymal duct of the Atelerix albiventris are similar to those of other mammals with a slight variation. It has also highlighted variation in the localization of αSMA across the regions of the epididymis of the animal.



2019 ◽  
Vol 25 (05) ◽  
pp. 1273-1282 ◽  
Author(s):  
Dalia Ibrahim ◽  
Fatma M. Abdel-Maksoud

AbstractIn order to evaluate the influence of reproductive activity on the functional role of the epididymal epithelium in the Egyptian dromedary camel, Connexin-43 (Cx-43), vascular endothelial growth factor (VEGF), and androgen receptor (AR) immunoreactivity in the epididymal epithelium and the fine structure of the principal, dark, basal, apical, and halo cells were investigated. The secretory activity of the principal cells was amplified in the breeding season, while its endocytotic function became more active in the nonbreeding season. This was evidenced by punctate strong immunoreactive signals for Cx-43, which appeared to be more intense in the apical region of these epithelial cells, and the extremely long slender stereocilia (microvilli) with multiple junctional complexes. The nonbreeding principal cells revealed granular immunoreactive signals for VEGF scattered in the apical and basal cytoplasm. Ultrastructurally, both extreme vacuolation and several multivesicular inclusion bodies were observed in their cytoplasm. Dark cell size greatly diminished in the nonbreeding season and their nuclear morphology greatly changed from oval to lobulated shape. The plasma membrane of the apical cells expressed several infoldings (microvilli) in the breeding season. However, it was almost smooth in the nonbreeding season except for a small microvillus that appeared as a bleb-like projection. In some regions, a strong dense immunoreactivity for VEGF could be recognized in the cytoplasm of the apical cells and some basal ones. Halo cells with numerous multivesicular inclusions occupying most of the cytoplasm and a lobulated eccentric nucleus were detected in the nonbreeding season. In conclusion, these findings indicate that the reproductive activity has a significant impact on the immunohistochemical and ultrastructural profiles of the epithelial cells lining the Egyptian dromedary camel epididymis.



Phytotaxa ◽  
2017 ◽  
Vol 314 (2) ◽  
pp. 251 ◽  
Author(s):  
YING ZHANG ◽  
CHENG-SHAN CAI ◽  
GUO-ZHU ZHAO

Dictyosporium wuyiense, a new anamorphic fungus collected on a dead branch of bamboo in Tongmugou, Wuyi Mountain, China, is described and illustrated. It is characterised by being cheiroid, septate, complanate, and yellow, with two types of conidia composed mostly of five parallel compact rows of cells, sometimes with variable hyaline apical vesical appendages. Type 1 conidia are longer and the three central rows are protruding with swollen apical cells; type 2 conidia are wider and fan-shaped, with rows of apical cells approximately the same length. The conidial morphology on potato dextrose agar plates was variable, most with 2–3 vesical appendages. In phylogenetic analyses of the internal transcribed spacer (ITS) of rDNA, Dictyosporium wuyiense clustered with most Dictyosporium species in Dictyosporiaceae, but was a distinct species. Both morphological and molecular evidence support its description as a new species. A brief review of Dictyosporium and allied species is provided.



Zootaxa ◽  
2017 ◽  
Vol 4281 (1) ◽  
pp. 232
Author(s):  
MARÍA INÉS CATALANO ◽  
CHRISTOPHER H. DIETRICH

 Two new genera, Sakakidikra n. gen. and Tricella n. gen., of tribe Dikraneurini McAtee are described from Ecuador, each based on a single new species, Sakakidikra jazminae n. sp. and Tricella antonellae n. sp. Both new genera described have only three apical cells in the forewing, an unusual characteristic in Typhlocybinae, but given the differences in the forewing and hind wing venation and male genitalia characters we consider it more appropriate to place the specimens in two separate monotypic genera. 



2015 ◽  
Vol 47 (1–2) ◽  
pp. 143-152
Author(s):  
Krystyna Idzikowska ◽  
Alicja Szweykowska

Fine structure of the protonema is described, with a special attention to its differentiation depending on the position of cells in the protanemal filament, as well as in response to a cytokinin treatment. Complexes of micro-filaments with osmiophilic globules represented structures of particular interest. They appeared temporarily, almost exclusively in apical cells. The cytokinin treatment resulted in the apical cells in an increased number of cytokinetic figures and in structural changes indicating increased metabolic activity. In the intercalary cells, changes in response to the cytokinin were much smaller and mostly concerned an augmented development of the thylakoid system in chloroplasts. After a prolonged (5 days) treatment, degeneration symptoms developed in all cells, particularly in nuclei and chloroplasts, whereas the structure of mitochondria was relatively stable. The results are compared with the observations concerning the cytokinin-induced gametophore buds and with the data of biochemical and physiological investigations of the protonema.



2014 ◽  
Vol 52 (2) ◽  
pp. 165-172
Author(s):  
Adam Woźny ◽  
Urszula Nowak ◽  
Alicja Szweykowska

In the protonema of <em>Ceratodon purpureus</em> (Hedw.) Brid., apical parts of the protonemal filaments (apical cells, initials of protonemal side branches and of gametophore buds) proved to be preferential sites of [<sup>14</sup>C]-leucine incorporation into proteins. In some filaments, a similar preference for [<sup>3</sup>H]-uridine incorporation into RNA was observed, whereas in others there was a rather uniform distribution of label over all cells. A short (0.5-2 h) treatment with cytokinin (N<sup>6</sup>-2-isopentenyladenine) enhanced [<sup>14</sup>C]-leucine incorporation, without changing the relative distribution of label. No such enhancement, as well as no change in label distribution could be observed in [<sup>3</sup>H]-uridine incorporation. No direct relationship seems to exist between the early promotion of protein synthesis by cytokinin in the protonema and cytokinin induction of gametophore buds.



2014 ◽  
Vol 49 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Maria Kwiatkowska ◽  
Mirosław Godlewski

Effects of GA<sub>3</sub> (10<sup>-11</sup>-10<sup>-4</sup> M) and AMO-1618 (10<sup>-6</sup>-10<sup>-4</sup> M) on the development of generatively matured thalli of <em>Chara vulgaris</em> were investigated during 21-day culture of plants in axenic conditions. It has been found that in the main bud the divisions of apical cells of the thalli are not stimulated by GA<sub>3</sub>, whereas in the lateral buds the cell divisions are stimulated by higher GA<sub>3</sub> concentrations. Subsequent mitotic activity of the apical cells in the branches of the main axis is not stimulated by GA<sub>3</sub>, whereas the lateral buds of these branches are activated. The development of rhizoids in younger nodes is accelerated by high GA<sub>3</sub> concentrations. The elongation of the polynuclear, internodal cells of the main axis and that of pleuridia are inhibited proportionally to the GA<sub>3</sub> concentration. AMO-1618 stimulates the development of new nodes, elongation of internodes and delays the activation of lateral buds as well as the formation of rhizoids. These results suggest that the GA<sub>3</sub>-induced inhibition of elongation of the thalli and diminution of the apical domination is connected with a high level of endogenous gibberellins in the generatively matured thallus.



2014 ◽  
Vol 66 (4) ◽  
pp. 25-34 ◽  
Author(s):  
Aneta Sulborska

Micromorphology and distribution of glandular and non-glandular trichomes on the above-ground organs of <em>Inula helenium </em>L. were investigated using light and scanning electron microscopy (SEM). Two types of biseriate glandular trichomes, i.e. sessile and stalk hairs, and non-glandular trichomes were recorded. Sessile glandular trichomes were found on all examined <em>I. helenium </em>organs (with their highest density on the abaxial surface of leaves and disk florets, and on stems), whereas stalk glandular trichomes were found on leaves and stems. Sessile trichomes were characterised by a slightly lower height (58–103 μm) and width (32–35 μm) than the stalk trichomes (62–111 μm x 31–36 μm). Glandular hairs were composed of 5–7 (sessile trichomes) or 6–9 (stalk trichomes) cell tiers. Apical trichome cell tiers exhibited features of secretory cells. Secretion was accumulated in subcuticular space, which expanded and ruptured at the top, and released its content. Histochemical assays showed the presence of lipids and polyphenols, whereas no starch was detected. Non-glandular trichomes were seen on involucral bracts, leaves and stems (more frequently on involucral bracts). Their structure comprised 2–9 cells; basal cells (1–6) were smaller and linearly arranged, while apical cells had a prozenchymatous shape. The apical cell was the longest and sharply pointed. Applied histochemical tests revealed orange-red (presence of lipids) and brow colour (presence of polyphenols) in the apical cells of the trichomes. This may suggest that beside their protective role, the trichomes may participate in secretion of secondary metabolites.



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