Spatial trade-offs in the digestive and reproductive systems of grape phylloxera

2011 ◽  
Vol 59 (6) ◽  
pp. 392 ◽  
Author(s):  
K. B. Andrews ◽  
D. Kemper ◽  
K. S. Powell ◽  
P. D. Cooper

Trade-offs between reproduction and other energy-requiring activities are present in insects. However, feeding and reproduction are not often thought to be trade-offs, although in small insects space may be limiting for both ingestion of food and egg development. This study characterised the structure of the digestive system of radicicolae Daktulosphaira vitifoliae (Hemiptera: Phylloxeridae) to investigate how feeding and egg development occur in this species. Using light and electron microscopy, the midgut of D. vitifoliae was observed to be composed of anterior and posterior regions, separated by a hindgut connection. The midgut is compressed during the development of parthenogenetically produced eggs in adults; individual eggs are ~30% of the adult length and in volume internally occupy 3–5% of the body cavity. The midgut posterior chamber is suggested to be essential for the continual supply of energy during periods of reduced food intake. The presence of the hindgut and an anal opening indicated that waste excretion through the anus was physiologically possible, although honeydew excretion was not observed. The structure of the digestive system of radicicolae D. vitifoliae is atypical, containing adaptations that may assist the survival of the monophagous insect during dispersal events to a new Vitis food source.

1999 ◽  
Vol 47 (3) ◽  
pp. 245 ◽  
Author(s):  
Lorenzo Alibardi ◽  
Michael B. Thompson

Formation of the scutes and dermis of the embryonic shell of the turtle Emydura macquarii was studied using light and electron microscopy. Shell morphogenesis begins at embryonic stage 15 and the shape of the shell is mostly completed by embryonic stage 19. The carapace anlagen arises as a thickening of the skin in the dorsal part of the mid-trunk region between the anterior and posterior limbs. This thickening extends ventro-laterally to form ridges at the margins of the carapace. Each ridge forms as a thick epidermal placode over a condensation of mesenchymal cells. The epidermis behind the advancing margins of the carapace is cuboidal or columnar but does not form placodes. The margins of the carapace expand rapidly in all directions. The plastron anlagen is derived from epidermal cells localised in the latero-ventral regions between the fore- and hind-limbs. Plastron placodes are present laterally, while the mid-ventral and central epidermis remains cuboidal or columnar but does not form placodes at embryonic stage 16. The plastron thickening rapidly moves from a latero-ventral position to a flat ventral position between embryonic stages 16 and 19. Dermal–epidermal anchoring complexes occur throughout placodes of both the carapace and plastron, but are rare in non-placode areas. The accumulation of a dense mesenchyme beneath the shell epidermis forms a dermal cushion that surrounds the body cavity. The superficial dermis close to the epidermis is made of mesenchymal fibroblasts at embryonic stage 19, although the inner-most areas contain bipolar fibroblasts and extracellular fibrils. Scutes with serrations at their borders form as invaginations of the epidermis into the dermis in the mid-dorsal areas of the embryo at embryonic stages 18–19. Dermal–epidermal anchoring complexes are located around the infoldings that form the scutes of the hinge region. The epidermis of the shell has 2–3 suprabasal cells at embryonic stages 19–22, and lacks keratinisation before embryonic stage 22 when it has 4–6 suprabasal layers with 2–3 external layers made of flat cells. The dermis thickens and has numerous collagen fibrils after embryonic stage 19. The formation of dermal bones begins at embryonic stage 18–19 in the plastron. Only small areas of the carapace near to the bridge have begun to form dermal bone at embryonic stage 19. Calcification begins at embryonic stage 19, but is still incomplete at embryonic stages 24–25.


Parasitology ◽  
1998 ◽  
Vol 116 (5) ◽  
pp. 437-447
Author(s):  
B. S. DEZFULI ◽  
S. ONESTINI ◽  
M. CARCUPINO ◽  
C. MISCHIATI

Light and electron microscopy were used to study the ultrastructure of the cement apparatus, namely cement glands and cement ducts of mature specimens of the acanthocephalan parasite Pomphorhynchus laevis Müller, 1776, recovered from the digestive tracts of fish Leuciscus cephalus Risso, 1826. In addition, the cement glands of immature P. laevis found within the body cavity of the fish Alburnus alburnus alborella De Filippi, 1844 were examined. In a mature male of P. laevis the 6 cement glands are rounded to oval in shape and each of them has an outer cytoplasmic layer containing nuclei and surrounding a space for storage of the cement material within the gland. The nuclei have an irregular outline and the cytoplasm of the cells contains round, membrane-bound secretory granules approximately 1 μm in diameter. Nuclei surrounded by secretory granules were present inside the gland lumen. Within the gland ducts of mature males, granules were present within the wall thickness and, inside the luminal area, mitochondria were encountered. In contrast, within the cement glands of immature P. laevis there were no secretory granules and the chromatin of the nuclei appeared condensed. The nature of the secretory product of the cement glands was investigated with histological and electrophoretic methods. A protein with molecular weight of 23 kDa was recorded as a major component of cement.


Parasitology ◽  
1924 ◽  
Vol 16 (1) ◽  
pp. 111-112
Author(s):  
Edward Hindle

In December, 1922, whilst dissecting a large female example of Bufo regularis, one of my students noticed a cylindrical structure extending along the ventral region of the body-cavity. A careful examination showed that this structure consisted of an elongated sac-like diverticulum of the right lung, containing an almost full-grown specimen of a dipterous larva, which could be seen through the membraneous wall of the diverticulum. The base of the latter, in addition to its point of origin from the lung, was also connected to the dorsal surface of the liver by strands of fibrous tissue, suggesting that the growth had been in existence some considerable time in order to cause such adhesions. Posteriorly, the diverticulum hung freely in the body cavity and extended to the extreme hinder end. Its dimensions were 5·5 cm. in length, by 0·5 cm. in diameter, but tapering towards each extremity.


1968 ◽  
Vol 46 (3) ◽  
pp. 321-327 ◽  
Author(s):  
M. A. Alikhan

Tbe circulatory system, lying in the mid-dorsal line of the body, consists of an oval heart, the opthalmic artery, and a dorsal abdominal artery.The digestive system comprises a wide, large alimentary tube and two pairs of digestive glands. An oesophagus, a proventriculus, midgut, and a short proctodacum or hindgut form the digestive tube. The digestive glands are very well developed and are beaded in form; each pair lies on either side of the alimentary canal.The reproductive organs are well developed in both sexes: in the male they consist of paired testes and their vas deferentia, and in the female paired bilobed ovaries and oviducts.A cerebral or supraoesophageal ganglion, a suboesophageal ganglion, and seven thoracic ganglia form the nervous system. The supraoesophageal ganglion is united with the suboesophageal ganglion by means of the circumoesophageal commissures, whereas the thoracic ganglia and suboesophageal ganglia are linked with each other by paired connectives.The gills and the tracheae are the organs of respiration. The gills are borne of the bases of the pleopods and are enclosed in the branchial chamber. The tracheae are located on the lateral lobes of the first two pleopods only.


1962 ◽  
Vol 40 (7) ◽  
pp. 1269-1275 ◽  
Author(s):  
Joan F. Bronskill

In third and fourth instar larvae of Aedes aegypti (L.), juveniles of the rhabditoid, DD136, penetrate the blood sinus and cardial epithelium of the proventriculus to enter the body cavity of the host, where they complete their development. By 5 hours, a thick capsule developed about many of the ensheathed immature adults of DD136 within the body cavity of A. aegypti larvae. This rapid defence reaction of the mosquito to DD136, which has both a melanin and a cellular manifestation, occurs both in the exotic mosquito A. aegypti and in the two endemic species tested, Aedes stimulans (Walker) and Aedes trichurus (Dyar). The resistance of A. stimulans to an endemic rhabditoid, possibly of the Diplogasteridae, is also similar. The histological structure of the capsule is not affected during metamorphosis in A. aegypti; however, during histogenesis of adult tissue displacement and (or) distortion of some tissues and organs may be caused by the presence of the capsule within the host's body cavity. The activity of the adult A. aegypti is normal when this distortion or displacement is minor. Though usually encapsulated DD136 are retained within the body cavity of A. aegypti during metamorphosis, sometimes they are partially or completely expelled from the host's body cavity at the time of molting.


2011 ◽  
Vol 279 (1732) ◽  
pp. 1287-1292 ◽  
Author(s):  
Roi Holzman ◽  
David C. Collar ◽  
Samantha A. Price ◽  
C. Darrin Hulsey ◽  
Robert C. Thomson ◽  
...  

Morphological diversification does not proceed evenly across the organism. Some body parts tend to evolve at higher rates than others, and these rate biases are often attributed to sexual and natural selection or to genetic constraints. We hypothesized that variation in the rates of morphological evolution among body parts could also be related to the performance consequences of the functional systems that make up the body. Specifically, we tested the widely held expectation that the rate of evolution for a trait is negatively correlated with the strength of biomechanical trade-offs to which it is exposed. We quantified the magnitude of trade-offs acting on the morphological components of three feeding-related functional systems in four radiations of teleost fishes. After accounting for differences in the rates of morphological evolution between radiations, we found that traits that contribute more to performance trade-offs tend to evolve more rapidly, contrary to the prediction. While ecological and genetic factors are known to have strong effects on rates of phenotypic evolution, this study highlights the role of the biomechanical architecture of functional systems in biasing the rates and direction of trait evolution.


1949 ◽  
Vol 26 (1) ◽  
pp. 1-15
Author(s):  
J. D. SMYTH

1. Plerocercoid larvae of the pseudophyllidean cestode Ligula intestinalis from the body cavity of roach, were cultured in vitro at 40°C. in a variety of saline and nutrient media. About 65% of such cultures were aseptic. 2. During cultivation, larvae produced acid by-products (unidentified) and the pH fell rapidly. 3. The presence of these acid by-products slowed down development, or, if present in sufficient quantity, caused death. 4. In order to obtain development in nutrient media in a period (3 days) comparable to that required in a bird (the normal host) it was necessary to renew the medium 24-hourly. 5. 6% of the eggs produced from a worm cultured in horse serum were fertile. Fertile eggs were never obtained from larvae cultured in any other media. 6. Certain bacterial infections had no apparent detrimental effect on development, but others were toxic. 7. Some larvae underwent development in non-nutrient medium (¾ strength Locke's solution). The exact conditions under which this occurred was not determined. 8. Fragments (3 cm. long), of larvae or larvae with either scolex or posterior half removed, underwent development to the stage of oviposition in nutrient media. 9. Histochemical examination revealed that the plerocercoid larvae were almost fat-free. During cultivation, very large quantities of cytoplasmic fat were produced the quantity being proportional to the duration of cultivation. Fat was produced even under starvation conditions (i.e. during cultivation in saline) and can be considered a metabolic by-product. 10. The fresh plerocercoid contained great quantities of glycogen in the parenchyma and muscle regions. After cultivation in nutrient or saline media, considerable quantities were still present.


Author(s):  
Vrushali P. Kale Vrushali Purushottam Kale

According to Ayurveda, Jatharagni plays main role in the digestion process. Jatharagni carries its functions through Pachaka pitta. Grahani is an organ of gastrointestinal tract located between Amashaya and Pakwashaya, where digestion takes place. According to classical literature Pitta is same as Agni. Tridosha also plays very important role in the digestion process. In the recent days, irregular life style affects the digestive system and Jatharagni very badly. Whenever Agni gets (Vikrut) unbalanced due to wrong food habits and lifestyle, it should be understood that along with Agni, Pachaka Pitta will also get disturbed. Agnimandya is the root cause of most of the disorders like Grahani. Grahani organ is the main location of Jatharagni. Grahani is the organ where Pachak Pitta and Samanvayu carry out digestion. The most important function of Grahani is digestion of food with the help of Jatharagni, Pachakpitta, Pittadhara Kala and Samnvayu. Agni inside the body, digest the food give strength and maintain health. Samanvayu regulates the movements of the Grahani and helps in digestion. Hence, in this article we attempt to analyze and correlate patho-physiology of Grahani with respect to Physiological analysis of Agni and disturbed doshas. Etiological factors induces imbalance in Jatharagni, Pachak Pitta and Samanvayu and prolonged imbalance state weakens the Pittadhara Kala, which results in disease Grahani. Health of Grahani entirely depends on balanced state of Jatharagni, Pachaka Pitta, Pittadhara Kala and Samanvayu. The irregular life style, incompatible food habits creates Ama causes Grahani, affecting the digestive system and Jatharagni very badly.


Author(s):  
Aleksey Borisovich Petrukhin

Gastroenterology belongs to one of the leading branches of therapy. In the structure of diseases of the internal organs, diseases of the digestive system occupy a particularly important place due to their high prevalence, which increases with age. As a rule, these diseases have a chronic, progressive, recurrent course, which ultimately leads to severe disorders of the activity of many organs and systems of the body. The article presents the basic requirements for the formation of a clinical diagnosis of diseases of the gastrointestinal tract, which are most common in the practice of a family doctor.


Author(s):  
M. Barson

Clarias gariepinus were collected from Lake Chivero, Zimbabwe, and examined for nematode parasites from November 2000 to May 2002. Of the 202 specimens collected, 42.6 % were infected with third-stage larvae of Contracaecum sp. in the body cavity. The intensity of the infection was 1-7 worms per fish (mean intensity = 2.2). Seasonal variation in the prevalence of the parasite was not obvious and there was no significant difference in the prevalence of infection between males and females (c2 = 2.228; P > 0.05). No significant relationship between host size and prevalence was established. There was also no significant relationship between intensity and the body condition factor (r = 0.11; P > 0.05). The low parasite prevalence may have been caused by the disruption of the infection cycle since piscivorous birds, which are the final hosts of the parasite, do not feed on C. gariepinus in Lake Chivero.


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