The fine structure of conidium development in Phialocephala dimorphospora

1974 ◽  
Vol 52 (10) ◽  
pp. 2119-2128 ◽  
Author(s):  
George C. Carroll ◽  
Fanny E. Carroll
Keyword(s):  
Developmental Stages ◽  
Lateral Wall ◽  
The Body ◽  
Lipid Bodies ◽  
Dense Granules ◽  
Conidium Formation ◽  
Secondary Conidium ◽  
Apical Vesicles ◽  
Myelin Figures ◽  
Primary Conidium

Sequential developmental stages from synchronously sporulating cultures of Phialocephala dimorphospora Kendrick have been examined. Apical vesicles characterize growth of the primary conidium. These are not, however, seen during secondary conidium formation; instead, large vesicles containing minute membrane fragments develop just below the phialide neck and contribute to wall formation as they fuse with the plasmalemma. The occurrence of microtubules in the neck of the phialide is restricted to primary conidium formation. Just as the primary conidial initial begins to swell, electron-dense granules 50-75 nm in diameter arise in association with the plasmalemma. Such granules are not seen during secondary conidium formation; they are thought to be involved in pigment deposition in the collarette. During both primary and secondary conidium production the conidia go through a sequence of maturation in which the cytoplasm becomes very dense and contains lipid bodies and flocculent aggregations of electron-transparent granules. Subsequently the conidia become less electron dense and reveal a simple internal substructure consisting of a nucleus, mitochondria, micro-bodies, free ribosomes, and presumed storage bodies. The plasmalemma becomes convoluted in a network of interdigitated grooves. Septum formation occurs rapidly and involves the fusion of vesicles with the lateral wall. Mature septa are non-perforate. Although Woronin bodies have been repeatedly observed in young conidia, they are never seen in mature conidia. Myelin figures associated with mitochondria occur consistently in the body of the phialide during conidiation. These may be the source of the lipid bodies in the conidia. In phialides from cultures over 1 week old, signs of senescence are apparent. These include vacuolization of the upper portion of the phialide and the presence of many disorganized sheets of membrane. Spores still present within the collarette of such phialides are smaller than those produced early in the life of the phialide.

A histological study of the invasive and developmental processes of the aphid pathogen Erynia neoaphidis (Zygomycotina: Entomophthorales) in the pea aphid Acyrthosiphon pisum

1990 ◽  
Vol 68 (10) ◽  
pp. 2153-2163 ◽  
Author(s):  
T. M. Butt ◽  
A. Beckett ◽  
N. Wilding
Keyword(s):  
Germ Tube ◽  
Acyrthosiphon Pisum ◽  
Histological Study ◽  
The Body ◽  
Plant Cuticle ◽  
Erynia Neoaphidis ◽  
Secondary Conidium ◽  
Aphid Pathogen ◽  
Aphid Host ◽  
Primary Conidium

On landing on the surface of an aphid host, the primary conidium of Erynia neoaphidis produced either a secondary conidium, a germ tube, or an appressorium. Appressoria were usually globose or clavate and each produced a single penetration peg. A circular bore hole marked the penetration site. Once the fungus had breached the cuticle, it formed protoplasts that failed to elicit an obvious immune response and multiplied rapidly in the haemocoel and in tissues. When the body of the host was occluded (about 3 days after penetration at 20 °C), the protoplasts regenerated a wall and differentiated into rhizoids, which were confined to the midventral region of the dead insect, pseudocystidia, and conidiophores. The rhizoids terminated in a digitate holdfast that adhered firmly to the plant cuticle but did not penetrate it. Conidiophores appeared to break out through the host cuticle using a combination of enzymatic and mechanical means. Key words: Erynia neoaphidis, Entomophthorales, infection, development, aphid.

Modeling the Mechanics of Tethers Pulled From the Cochlear Outer Hair Cell Membrane

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Kristopher R. Schumacher ◽  
Aleksander S. Popel ◽  
Bahman Anvari ◽  
William E. Brownell ◽  
Alexander A. Spector
Keyword(s):  
Cell Membrane ◽  
Hair Cell ◽  
Outer Hair Cell ◽  
Lateral Wall ◽  
Outer Hair Cells ◽  
The Body ◽  
Computational Method ◽  
Membrane Properties ◽  
Bending Modulus ◽  
Sound Amplification

Cell membrane tethers are formed naturally (e.g., in leukocyte rolling) and experimentally to probe membrane properties. In cochlear outer hair cells, the plasma membrane is part of the trilayer lateral wall, where the membrane is attached to the cytoskeleton by a system of radial pillars. The mechanics of these cells is important to the sound amplification and frequency selectivity of the ear. We present a modeling study to simulate the membrane deflection, bending, and interaction with the cytoskeleton in the outer hair cell tether pulling experiment. In our analysis, three regions of the membrane are considered: the body of a cylindrical tether, the area where the membrane is attached and interacts with the cytoskeleton, and the transition region between the two. By using a computational method, we found the shape of the membrane in all three regions over a range of tether lengths and forces observed in experiments. We also analyze the effects of biophysical properties of the membrane, including the bending modulus and the forces of the membrane adhesion to the cytoskeleton. The model’s results provide a better understanding of the mechanics of tethers pulled from cell membranes.

scholarly journals Seasonal occurrence of some larval stages of endoparasites in three cyprinids from the Nwanedi-Luphephe dams, the Limpopo River System, South Africa

2015 ◽  
Vol 52 (3) ◽  
pp. 229-235 ◽  
Author(s):  
E. M. Mbokane ◽  
J. Theron ◽  
W. J. Luus-Powell
Keyword(s):  
Developmental Stages ◽  
River System ◽  
Intestinal Wall ◽  
The Body ◽  
Seasonal Occurrence ◽  
Seasonal Fluctuations ◽  
Metazoan Parasites ◽  
Larval Stages ◽  
Parasite Communities ◽  
Third Stage

Abstract This study provides information on seasonal occurrence of developmental stages of endoparasites infecting three cyprinids in the Nwanedi-Luphephe dams, Limpopo River System. Labeobarbus marequensis (Smith, 1841), Barbus trimaculatus Peters, 1852 and Barbus radiatus Peters, 1853 were investigated seasonally from January 2008 to October 2008. The following larvae of metazoan parasites were collected: Diplostomum sp. from the eyes of L. marequensis and B. trimaculatus; Ornithodiplostomum sp. from the gills of B. trimaculatus; Posthodiplostomum sp. from muscle, skin and fins of B. trimaculatus and B. radiatus; third-stage Contracaecum larvae (L3) from the mesentery fats and on the liver lobes of L. marequensis and B. trimaculatus and gryporynchid cestode larvae from the outer intestinal wall of B. radiatus. All the flukes encountered were metacercariae. Diplostomum sp. and Contracaecum sp. dominated the parasite communities. Their prevalence exhibited seasonal fluctuations with maxima in summer. Factors likely to influence fish infection such as the body size of fish and their condition factors were also briefly considered in this study.

The Medial Wall of the Cavernous Sinus: Microsurgical Anatomy

Neurosurgery ◽  
2004 ◽  
Vol 55 (1) ◽  
pp. 179-190 ◽  
Author(s):  
Alexandre Yasuda ◽  
Alvaro Campero ◽  
Carolina Martins ◽  
Albert L. Rhoton ◽  
Guilherme C. Ribas
Keyword(s):  
Pituitary Gland ◽  
Cavernous Sinus ◽  
Thin Sheet ◽  
Single Layer ◽  
Lateral Wall ◽  
The Body ◽  
Medial Wall ◽  
Microsurgical Anatomy ◽  
Pituitary Fossa ◽  
Adjacent Structures

Abstract OBJECTIVE: This study was conducted to clarify the boundaries, relationships, and components of the medial wall of the cavernous sinus (CS). METHODS: Forty CSs, examined under ×3 to ×40 magnification, were dissected from lateral to medial in a stepwise fashion to expose the medial wall. Four CSs were dissected starting from the midline to lateral. RESULTS: The medial wall of the CS has two parts: sellar and sphenoidal. The sellar part is a thin sheet that separates the pituitary fossa from the venous spaces in the CS. This part, although thin, provided a barrier without perforations or defects in all cadaveric specimens studied. The sphenoidal part is formed by the dura lining the carotid sulcus on the body of the sphenoid bone. In all of the cadaveric specimens, the medial wall seemed to be formed by a single layer of dura that could not be separated easily into two layers as could the lateral wall. The intracavernous carotid was determined to be in direct contact with the pituitary gland, being separated from it by only the thin sellar part of the medial wall in 52.5% of cases. In 39 of 40 CSs, the venous plexus and spaces in the CS extended into the narrow space between the intracavernous carotid and the dura lining the carotid sulcus, which forms the sphenoidal part of the medial wall. The lateral surface of the pituitary gland was divided axially into superior, middle and inferior thirds. The intracavernous carotid coursed lateral to some part of all the superior, middle, and inferior thirds in 27.5% of the CSs, along the inferior and middle thirds in 32.5%, along only the inferior third in 35%, and below the level of the gland and sellar floor in 5%. In 18 of the 40 CSs, the pituitary gland displaced the sellar part of the medial wall laterally and rested against the intracavernous carotid, and in 6 there was a tongue-like lateral protrusion of the gland that extended around a portion of the wall of the intracavernous carotid. No defects were observed in the sellar part of the medial wall, even in the presence of these protrusions. CONCLUSION: The CS has an identifiable medial wall that separates the CS from the sella and capsule of the pituitary gland. The medial wall has two segments, sellar and sphenoidal, and is formed by just one layer of dura that cannot be separated into two layers as can the lateral wall of the CS. In this study, the relationships between the medial wall and adjacent structures demonstrated a marked variability.

Developmental stages in the Digenea

Parasitology ◽  
1964 ◽  
Vol 54 (2) ◽  
pp. 295-312 ◽  
Author(s):  
Elon E. Byrd ◽  
William P. Maples
Keyword(s):  
Body Wall ◽  
Developmental Stages ◽  
Snail Host ◽  
The Body ◽  
Body Movements ◽  
Hatching Enzyme ◽  
Apical Papilla ◽  
Short Time ◽  
Membranous Body ◽  
Egg Capsule

The naturally oviposited egg of Dasymetra conferta is fully embryonated and it hatches only after it is ingested by the snail host, Physa spp.Hatching appears to be in response to some stimulus supplied by the living snail. The stimulus causes the larva to exercise a characteristic series of body movements and to liberate a granular sustance (hatching enzyme) from the larger pair of its cephalic glands. This enzyme reacts with the vitelline fluid to create pressure within the egg capsule, and with the cementum of the operculum, so that it may be lifted away. The larva's escape from the shell, therefore, is due to a combination of pressure and body movements.The hatched larva has a membranous body wall, supporting six epidermal plates, an apical papilla, two penetration glands and a central matrix (the presumptive brood mass).It lives for about an hour within the snail and during this time there is a reorganization of the central matrix which terminates in the formation of an 8-nucleated syncytial brood mass.The miracidial ‘case’, consisting of the body wall and the epidermal plates, ultimately ruptures to liberate the brood mass. Once the brood mass is free it penetrates through the gut wall in an incredibly short time.

scholarly journals Early ontogenesis of the angelfish, Pterophyllum scalare Schultze, 1823 (Cichlidae)

2012 ◽  
Vol 10 (3) ◽  
pp. 567-576 ◽  
Author(s):  
Agata Korzelecka-Orkisz ◽  
Zuzanna Szalast ◽  
Dorota Pawlos ◽  
Izabella Smaruj ◽  
Adam Tañski ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Artemia Salina ◽  
The Body ◽  
Pigment Cells ◽  
Alkaline Ph ◽  
Membrane Structures ◽  
Egg Membrane ◽  
Newly Hatched Larvae ◽  
Item Size ◽  
Pterophyllum Scalare

This study describes the egg membrane structures of angelfish (Pterophyllum scalare), morpho-physiological changes during angelfish embryogenesis from activation to hatching under optimal conditions (28°C; pH 6.8), the developing larvae and fry, the effect of alkaline pH on the early developmental stages of the species, the relationship between food item size and fry survival. Egg membranes (thin, transparent, 1.67-2.18 µm thick) are covered by a sticky substance. The amber-coloured angelfish eggs were oval in shape, with average diameters of 1.436 and 1.171 mm, i.e., a mean volume of 1.033 ± 0.095 mm³. The survival rate of embryos and larvae kept in water with an elevated, slightly alkaline pH was very low: as few as 2% of the embryos survived, while in the batch kept in optimal water conditions very few eggs died. The first larvae hatched after 1288 h of embryonic development. The newly hatched larvae measured on average 2.60 ± 0.093 mm and had large (0.64 ± 0.077 mm³) yolk sacs. They attached themselves to the substrate with a secretion of thin, viscous threads, which was released from glands situated on the top of the head. The glands vanished on day 5. The 1-day-old larvae showed the first pigment cells on the body and the eyes of the 2-day-olds were already fully pigmented. Between day 4 and 5 of larval life, the larvae began feeding on live food. The 23-day-old fry looked like a miniature versions of the adults. Mortality of the angelfish larvae during their first days after hatching was higher in those fed brine shrimp (Artemia salina) nauplii than those fed protozoans and rotifers.

The morphology of the British Prostriata with particular reference to Ixodes hexagonus Leach. II

Parasitology ◽  
1953 ◽  
Vol 42 (3-4) ◽  
pp. 161-186 ◽  
Author(s):  
D. R. Arthur
Keyword(s):  
Developmental Stages ◽  
Egg Laying ◽  
The Body ◽  
Dorsal Margin ◽  
Leg Length ◽  
Large Size ◽  
Attachment Sites ◽  
Wide Range ◽  
Primitive Condition ◽  
Basis Capituli

The palps of all stages of Ixodes trianguliceps are provided with a ventral plate below the basal article; formerly this plate was thought to be the first palpal article. This article in the larva and nymph is produced forward into a spur, but in the female tick this spur is incorporated into the basis capituli as the sella. The hypostomes of I. trianguliceps and I. canisuga are redescribed to clear up existing inaccuracies.Ticks in which the rostrum does not extend beyond the apex of the first palpal article are found on birds, and this probably represents a primitive condition. Those with palpal spurs, which may or may not be fused with the basis capituli, are found on birds (not in Britain) or on mammals of the mouse size group, and those where the rostrum is produced beyond the first palpal article occur on a wide range of large and small animals. The longer and more heavily toothed digits of ticks appear to be associated with a wide host range and vice versa. The structure of the digit may also influence the choice of attachment sites by ticks on their hosts because the microstructure of the skin varies in different parts.Variations in size and form of the scuta of some British ticks are described, and the mean growth rate is ascertained from this data. The information shows that the material of I. ricinus and I. hexagonus is homogeneous, and that specific differences occur in size, shape, the position and type of dermal ducts and in the relation between scutal and alloscutal bristles.The morphology of Gené's organ in I. hexagonus is described. It consists of a basal sac-like portion surmounted by four horns and lined with a cuticle beneath an epithelium. The gland is a proliferation of the epithelium and located near the bifurcation of the base into the horns. A watery refractile fluid, secreted by the gland, accumulates between the epidermis and the cuticle in the horn-like extensions. Proximally the thick endocuticle and epidermis lie close together, and two cuticularized rods penetrate the endocuticle for about half-way along the stalk. The rods arise from the postero-dorsal margin of the basis capituli. Muscles, arising from the free ends of the rods, pass back to near the hind-margin of the scutum; they retract the basis capituli after egg laying and indirectly assist in the retraction of Gené's organ. A suggested mechanism for everting Gené's organ in I. hexagonus is outlined.During feeding the opisthosomatic cuticle of all developmental stages of the tick is much stretched. In the larva, where the cuticle is thin, this is effected by the flattening of the epicuticular pleats, but nymphs and females have, in addition, two longitudinal folds alongside the body which stretch to a far greater extent than do the epicuticular pleats. Similar folds are present between the hard ventral plates and the scutum and between the epimeral and median plates in the male. Coupled with the large size of the male digit, this suggests that morphologically, at least, males can imbibe blood.The growth of the leg segments of I. hexagonus is not constant from stage to stage, and as a result the shortest ‘leg-length’ of the female exceeds the longest ‘leg-length’ of the male.

Growth, development and allometry of Philophthalmus nocturnus in the eyes of domestic chicks

1992 ◽  
Vol 66 (2) ◽  
pp. 100-107 ◽  
Author(s):  
V. G. M. Swarnakumari ◽  
R. Madhavi
Keyword(s):  
Growth Rate ◽  
Developmental Stages ◽  
Adult Stage ◽  
The Body ◽  
Lag Phase ◽  
Allometric Growth ◽  
Body Width ◽  
Rapid Phase ◽  
Growth Development ◽  
Two Phases

ABSTRACTFifty day-old chicks were each infected with 10 excysted metaccreariae of Philophthalimus nocturnus Looss. 1907 around each orbit and growth, development and allometry were studied. The growth rate showed two phases over a period of 35 days, a limited lag phase lasting two days post-infection in which flukes did not exceed 440 μm in length, and a rapid phase during which growth was rapid and flukes reached a size of 3·008–3·504 mm on day 35. Five developmental stages were noticed during the course of development of the metacercaria to the egg-producing adult stage. Eggs appeared in the uterus on day 14 and oculate miracidia on day 25. The hindhody, testes and ovary showed positive allometric growth, the pharnyx less so, whereas negative allometric growth was shown by the forebody. Body width, oral sucker and ventral sucker were close to isometry, growing at the same rate as the body length.

scholarly journals Morphological description of the developmental stages of Parauchenipterus galeatus (Linnaeus, 1766) (Siluriformes, Auchenipteridae) on the floodplain of the upper Paraná River

1999 ◽  
Vol 59 (3) ◽  
pp. 429-438 ◽  
Author(s):  
P. V. SANCHES ◽  
K. NAKATANI ◽  
A. BIALETZKI
Keyword(s):  
Developmental Stages ◽  
Paraná River ◽  
The Body ◽  
Morphological Description ◽  
Body Parts ◽  
Morphometric Data ◽  
Double Membrane ◽  
Parana River ◽  
Upper Paraná River ◽  
Development Analysis

We provide morphological and morphometric descriptions of the developmental stages of Parauchenipterus galeatus, from the floodplain of the Upper Paraná River. Specimens were obtained by induced spawning. The species has large adhesive eggs with a double membrane. The incubation period is long, 65 hours at 27°C. The larvae are well developed at hatching, with relatively rapid larval development. Analysis of the morphometric data showed that the body parts of P. galeatus grow proportionately.

scholarly journals Seasonal maturation of Glypthelmins vitellinophilum (Trematoda: Digenea) in Lysapsus limellus (Anura: Pseudidae) from an Argentinian subtropical permanent pond

2006 ◽  
Vol 66 (1a) ◽  
pp. 85-93 ◽  
Author(s):  
M. I. Hamann
Keyword(s):  
Body Length ◽  
Developmental Stages ◽  
Small Body ◽  
Stage Iv ◽  
The Body ◽  
Climatic Fluctuations ◽  
Parasite Stage ◽  
Permanent Pond ◽  
Body Sizes ◽  
The Relationship

From December 1995 to November 2000, the seasonal maturation of Glypthelmins vitellinophilum Dobbin, 1958, in its definitive host, the frog Lysapsus limellus Cope, 1862, was studied in a subtropical permanent pond in northeastern Argentina. The objectives of this study were: 1) to determine the infrapopulation dynamics of the parasite, analyzing the seasonal maturation cycle throughout the years; and 2) to examine the relationship between the intensity of trematode infection in different developmental stages (recruitment, growth and maturation) and the host's body length. Of a total of 1,400 frogs examined over 60 months (5 years), 38% were found to be infected with G. vitellinophilum, and the intensity of infection was 1-15 trematodes per frog. Specimens of G. vitellinophilum were present in L. limellus throughout the years, but did not show a pronounced seasonal maturation cycle. Possible reasons for these findings are discussed with reference to climatic fluctuations and biotic factors. The infective period of the parasite (stage I) occurred in summer, autumn and spring, coinciding with the time each frog cohort appeared. These infections were found principally in small body sizes (classes 1 and 2) of L. limellus. Juvenile and nongravid specimens of worms (stage II and III) were found in frogs of different body sizes throughout the period of investigation. Gravid specimens of the parasite (stage IV) were generally recorded in autumn, winter and spring, mainly in the bodies of larger frogs. The body length of Trematodes in stages I and IV was significantly and positively correlated with that of the frogs.

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