Reproduction in Australian Pearl Oysters (Lamellibranchia). I. Pinctada albina (Lamarck): Gametogenesis

1958 ◽  
Vol 9 (1) ◽  
pp. 135 ◽  
Author(s):  
DJ Tranter
Keyword(s):  
Germ Cells ◽  
The Body ◽  
First Year ◽  
Visceral Mass ◽  
Male And Female ◽  
Pearl Oysters ◽  
Sexually Mature ◽  
Development Proceeds ◽  
Urogenital Papilla ◽  
Do So

The primary gonad of Pinctada albina consists of paired systems of confluent tubules ("follicles") opening to the exterior at laterally situated urogenital openings. There are no morphologically differentiated gonoducts; the gonads empty into a short ciliated genital vestibule through the primary gonad follicles. A duct from each kidney enters each vestibule just inside the urogenital papilla. There is no superficial difference between the gonads of male and female, except in colour: the testis is cream and the ovary yellow. The follicles originate in the connective tissue behind the openings, and spread through the space between external epithelium and viscera, by invagination, branching, and ramification. As they do so they carry with them, attached to the follicle walls, the primary germ cells ("stem cells"). There are four main follicular systems on each side of the body, but as development proceeds they tend to coalesce. Soon the gonad loses its bilateral appearance and envelops the whole visceral mass. The species becomes sexually mature in its first year, often within 4 or 5 months.

SPECT-Befunde bei Hemiparkinson-Syndrom mit 99mTc-HMPAO

1989 ◽  
Vol 28 (03) ◽  
pp. 92-94 ◽  
Author(s):  
C. Neumann ◽  
H. Baas ◽  
R. Hefner ◽  
G. Hör
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Basal Ganglia ◽  
Neuronal Activity ◽  
Tracer Uptake ◽  
The Body ◽  
99Mtc Hmpao ◽  
Do So

The symptoms of Parkinson’s disease often begin on one side of the body and continue to do so as the disease progresses. First SPECT results in 4 patients with hemiparkinsonism using 99mTc-HMPAO as perfusion marker are reported. Three patients exhibited reduced tracer uptake in the contralateral basal ganglia One patient who was under therapy for 1 year, showed a different perfusion pattern with reduced uptake in both basal ganglia. These results might indicate reduced perfusion secondary to reduced striatal neuronal activity.

scholarly journals Reproductive Isolation and Morphogenetic Evolution in Drosophila Analyzed by Breakage of Ethological Barriers

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 231-242 ◽  
Author(s):  
Lucas Sánchez ◽  
Pedro Santamaria
Keyword(s):  
Reproductive Isolation ◽  
Germ Cells ◽  
Morphological Analysis ◽  
Seminal Fluid ◽  
Germ Line ◽  
Regulatory Gene ◽  
Motile Sperm ◽  
Male And Female ◽  
Drosophila Yakuba

Abstract This article reports the breaking of ethological barriers through the constitution of soma-germ line chimeras between species of the melanogaster subgroup of Drosophila, which are ethologically isolated. Female Drosophila yakuba and D. teissieri germ cells in a D. melanogaster ovary produced functional oocytes that, when fertilized by D. melanogaster sperm, gave rise to sterile yakuba-melanogaster andteissieri-melanogaster male and female hybrids. However, the erecta-melanogaster and orena-melanogaster hybrids were lethal, since female D. erecta and D. orena germ cells in a D. melanogaster ovary failed to form oocytes with the capacity to develop normally. This failure appears to be caused by an altered interaction between the melanogaster soma and the erecta and orena germ lines. Germ cells of D. teissieri and D. orena in a D. melanogaster testis produced motile sperm that was not stored in D. melanogaster females. This might be due to incompatibility between the teissieri and orena sperm and the melanogaster seminal fluid. A morphological analysis of the terminalia of yakuba-melanogaster and teissieri-melanogaster hybrids was performed. The effect on the terminalia of teissieri-melanogaster hybrids of a mutation in doublesex, a regulatory gene that controls the development of the terminalia, was also investigated.

scholarly journals Voyageurs malgré eux: Silence, embodiment, and exposure in Minh Tran Huy and Doan Bui

2021 ◽  
pp. 095715582110259
Author(s):  
Caroline D. Laurent
Keyword(s):  
Second Generation ◽  
Life Stories ◽  
The Body ◽  
French Society ◽  
Dual Identity ◽  
Vietnamese Literature ◽  
Asian Descent ◽  
Vietnamese Community ◽  
Body Self ◽  
Do So

In recent Franco-Vietnamese literature written by descendants of immigrants, the liminality of exile is portrayed in all its complexity through migrant bodies – that of parents’ bodies – and through political and social bodies – linked to History and the Việt Kiều’s positionality in French society. The experience of external movement becomes an internal one, creating porosity between the outside and the body, self and others, places and times. This article argues that, in Minh Tran Huy’s Voyageur malgré lui and Doan Bui’s Le Silence de mon père, by representing their family’s migration, both authors present the silenced histories of the Vietnamese community in France. In order to do so, Tran Huy and Bui first focus on uncovering and writing the stories of their silent fathers: through their embodiment of exilic history, the fathers transmit the wound of their immigrant condition to their daughters. Consequently, daughters come to manifest similar bodily expressions of traumas they have not experienced and know little about. The fathers’ histories are eventually voiced and re-invested by the second generation. This shows how the unearthing of their fathers’ life stories is also about reappropriating a dual identity as well as making Asian diasporic perspectives and histories visible, notably to create new avenues of representation for French individuals of Asian descent.

PRE-MATERNAL ISOLATION EFFECTS ON BEHAVIOUR AND ENDOCRINE FUNCTION OF OFFSPRING

1969 ◽  
Vol 62 (2) ◽  
pp. 367-384 ◽  
Author(s):  
A. M. Sackler ◽  
A. S. Weltman ◽  
R. Schwartz ◽  
P. Steinglass
Keyword(s):  
Locomotor Activity ◽  
Growth Rates ◽  
Female Offspring ◽  
The Body ◽  
Endocrine Function ◽  
Male And Female ◽  
Isolation Stress ◽  
Developmental Growth ◽  
Body Weights ◽  
And Control

ABSTRACT This report was designed to determine combined effects of maternal endocrine imbalances and abnormal behaviour due to prolonged isolation stress of female mice on the behaviour, developmental growth rate and endocrine function of their offspring. Sixty female albino mice averaging 19 g were divided equally into isolated and control groups. The isolated females were housed singly; control females were maintained in groups of 2 mice per cage. After observation of behavioural and physiological effects characteristic of isolation stress in the test mice, all isolated and control mice were mated after a 6½ month experimental, isolation period. No differences were observed in fertility and fecundity of the two groups of mothers. Analyses of developmental growth rates of the litters of the isolated versus control mothers showed significantly lower body weights in the test offspring at 3 and 4 weeks of age. The body weights of the female offspring remained significantly lower from the 4th to 11th weeks. The effects on the body weights of the male offspring declined and were no longer statistically significant at the 5th to 11 weeks. Locomotor activity at 4½ and 8 weeks of age was markedly or significantly higher in the male and female mice from isolated mothers. Tail-blood samples taken prior to autopsy at 5 and 11 weeks of age revealed significant decreases in the total leukocyte and eosinophil counts of both sexes. At the two ages, the absolute and relative spleen and thymus weights of the male and female offspring were markedly and/or significantly lower than the values observed in counterpart young from control females. Significant decreases were also observed in the absolute gonadal organ weights of both sexes at 11 weeks of age. The various data indicated inhibited growth rates, heightened locomotor activity and evasiveness, as well as evidence of increased adrenocortical function in the offspring from test mothers. The gonadal weight decreases suggested retarded gonadal development. Further studies using split-litter techniques are required to differentiate the effects of prenatal endocrine imbalances versus postnatal maternal influence (i. e., nursing care) on the offspring.

scholarly journals Defence Is a Priority in Female Juveniles and Adults of Taxus baccata L.

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 844
Author(s):  
Kinga Nowak ◽  
Marian J. Giertych ◽  
Emilia Pers-Kamczyc ◽  
Peter A. Thomas ◽  
Grzegorz Iszkuło
Keyword(s):  
Starch Content ◽  
Pollen Grains ◽  
Pot Experiment ◽  
Total Phenolic ◽  
First Year ◽  
Specific Response ◽  
Taxus Baccata ◽  
Dioecious Plants ◽  
A Priority ◽  
Sexually Mature

Female individuals of dioecious plants invest their resources more in storage and defence, and the males have higher nitrogen content invested in the production of pollen grains. An unresolved problem is whether this strategy occurs only in sexually mature plants or can also occur in juvenile plants. To answer this, Taxus baccata (L.) needles from the mature plants and rooted cuttings (juveniles) in a pot experiment were compared for the content of carbon, nitrogen, starch, total non-structural carbohydrates (TNC), and total phenolic compounds (TPhC). The results indicate that the differences between sexes occurred mainly in sexually mature plants, where the starch content was higher in females and nitrogen in males. However, the novelty of the results is that TPhC was generally higher in females than males in both adults and juveniles, suggesting that defence is a priority for females from an early age. We do not know if this is an innate trait because the strobili production (albeit at a very low level) of juveniles was observed in all individuals after the autumn of the first year. We found no effect of fertilization on sex-specific response in the pot experiment, which may be related to the lower reproductive effort of juveniles.

The Body in Theory

1998 ◽  
Vol 16 (4) ◽  
pp. 387-400 ◽  
Author(s):  
Felicity J Callard
Keyword(s):  
Queer Theory ◽  
20Th Century ◽  
The Body ◽  
The Other ◽  
Industrial Capitalism ◽  
Late 20Th Century ◽  
The Social ◽  
Theoretical Investigations ◽  
The One ◽  
Do So

Geographers are now taking the problematic of corporeality seriously. ‘The body’ is becoming a preoccupation in the geographical literature, and is a central figure around which to base political demands, social analyses, and theoretical investigations. In this paper I describe some of the trajectories through which the body has been installed in academia and claim that this installation has necessitated the uptake of certain theoretical legacies and the disavowal or forgetting of others. In particular, I trace two related developments. First, I point to the sometimes haphazard agglomeration of disparate theoretical interventions that lie under the name of postmodernism and observe how this has led to the foregrounding of bodily tropes of fragmentation, fluidity, and ‘the cyborg‘. Second, I examine the treatment of the body as a conduit which enables political agency to be thought of in terms of transgression and resistance. I stage my argument by looking at how on the one hand Marxist and on the other queer theory have commonly conceived of the body, and propose that the legacies of materialist modes of analysis have much to offer current work focusing on how bodies are shaped by their encapsulation within the sphere of the social. I conclude by examining the presentation of corporeality that appears in the first volume of Marx's Capital. I do so to suggest that geographers working on questions of subjectivity could profit from thinking further about the relation between so-called ‘new’ and ‘fluid’ configurations of bodies, technologies, and subjectivities in the late 20th-century world, and the corporeal configurations of industrial capitalism lying behind and before them.

scholarly journals Cleaner birds: an overview for the Neotropics

2010 ◽  
Vol 10 (4) ◽  
pp. 195-203 ◽  
Author(s):  
Ivan Sazima ◽  
Cristina Sazima
Keyword(s):  
Marine Mammals ◽  
Bird Species ◽  
The Body ◽  
Domestic Dog ◽  
Large Herbivores ◽  
Broad Category ◽  
Organic Debris ◽  
Marine Reptiles ◽  
Black Vulture ◽  
Do So

Several bird species feed on a variety of external parasites and epibionts, organic debris, dead and wounded tissue, clots and blood, and secretions from the body of other vertebrates (hosts or clients). We present an overview of so called cleaner birds from the Neotropics based on field records, literature, and photo survey. We found that 33 bird species in 16 families practice cleaning even if some of them do so very occasionally. The birds range from the Galápagos ground finch Geospiza fuliginosa to the widespread black vulture Coragyps atratus. Clients mostly are large herbivores such as capybaras, deer, and livestock, but also include medium-sized herbivores such as iguanas and tortoises, and carnivores such as boobies and seals - a few bird species associate with these latter marine mammals. No carnivorous terrestrial mammal client is recorded to date except for a domestic dog, from whose hair black vultures picked organic debris. Some clients adopt particular inviting postures while being cleaned, whereas others are indifferent or even disturbed by the activity of cleaner birds. Capybaras, giant tortoises, and iguanas are among the inviting clients, whereas boobies try to dislodge the 'vampire' finch Geospiza difficilis. Most of the Neotropical cleaner birds may be lumped in one broad category (omnivores that dwell in open areas and associate with large to medium-sized herbivores). A second, restricted category accommodates some species from Patagonia and the Galápagos Islands (omnivores that dwell in open areas and associate with carnivorous marine mammals, or seabirds and marine reptiles). Two still more restricted categories accommodate the following: 1) forest-dwelling cleaner birds; and 2) marine coastal cleaners. Additional records of Neotropical cleaner birds will mostly fall in the broad category.

Development of the germ cells and reproductive primordia in male and female embryos of Rhodnius prolixus Stål (Hemiptera: Reduviidae)

1994 ◽  
Vol 72 (6) ◽  
pp. 1100-1119 ◽  
Author(s):  
B. S. Heming ◽  
E. Huebner
Keyword(s):  
Germ Cells ◽  
Dorsal Surface ◽  
Interstitial Cells ◽  
Rhodnius Prolixus ◽  
Posterior Pole ◽  
Male And Female ◽  
Functional Aspects ◽  
Pole Plasm ◽  
Blastodermal Cells ◽  
Sheath Cells

Newly deposited eggs of Rhodnius prolixus lack a visible pole plasm and require 14 days to develop at 27 °C and 70% RH. The first germ cells originate at 9% of embryogenesis by asynchronous mitosis of blastodermal cells behind the germ Anlage at the posterior pole of the egg. From 9 to 17%, these proliferate to a mean of 270 cells and, from 13 to 18%, migrate forward over the dorsal surface of the mesoderm and lodge in abdominal segments 3–7. Between 22 and 30%, they shift laterally and segregate into three or four paired clumps between segments 3 and 4, 4 and 5, 5 and 6, and, sometimes, 6 and 7 and, from 30 to 37%, gradually assemble into a continuous longitudinal mass on either side of segments 3–6, where they begin to associate with mesodermal cells. Between 37 and 46%, these collect between (males) and around the germ cells to form the rudiments of the terminal filaments (females), inner and outer gonadal sheaths, interstitial cells (males), and primary exit ducts. Dorsally situated sheath cells then invaginate ventrally into each gonadal rudiment, partitioning it into seven compartments, each containing a mean of 15 oogonia or 16 spermatogonia. These seem to fuse into a rosette, at least in females, but do not begin to divide again until after hatch. Excluded germ cells lodge within the rudiments of one or both exit ducts. The evolutionary and functional aspects of our findings are addressed and new observations are presented on the mechanism of anatrepsis.

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