Hatching Stimulus Research Articles

Synthesis and Testing of Compounds That Inhibit Soybean Cyst Nematode Egg Hatch

Soybean cyst nematode infestation continues to be a serious agricultural problem. As part of an interdisciplinary effort to identify a biorational solution to the problem, analogs of glycinoeclepin A, a natural hatching stimulus of the nematode, were prepared and tested. Several of the analogs were discovered to inhibit the hatching of soybean cyst nematode eggs. On the basis of the results of egg hatch tests, the minimum functionality for egg hatch inhibition appears to be a keto diacid.

Structure-activity Relationship of Glycinoeclepin A

Abstract In a course of studies on glycinoeclepin A, which is a natural hatching stimulus for the soybean cyst nematode isolated from the roots of kidney bean, the relationship of the structure and activity has been investigated with use of various synthetic compounds.

Release of Potato Cyst Nematode Hatching Stimulus from Hairy Root Cultures of Some Solanaceae Plants.

Release of Potato Cyst Nematode Hatching Stimulus from Hairy Root Cultures of Some Solanaceae Plants.

Production of Potato Cyst Nematode Hatching Stimulus by Hairy Root Cultures of Tomato.

Hairy root clones of tomato (Lycopevsicon esculentum) were obtained by inoculation of the stems of sterile plants with Agrobacterium rhizogenes. The transformed root cultures produced a potato cyst nematode hatching stimulus, which was detected both in the extract of the cultured roots and in th culture medium. The hatching stimulus was also produced by non-transformed tomato root cultures. Large portions of the hatching stimuli synthesized in the hairy and non-transformed roots were found to be released into the medium. Five independent clones of the tomato hairy root cultures displayed considerable variation in the production of stimulus.

Triterpenoid total synthesis. Part 2. Synthesis of glycinoeclepin A, a potent hatching stimulus for the soybean cyst nematode

Glycinoeclepin A, a natural hatching stimulus for the soybean cyst nematode, was enantioselectively synthesized starting from two chiral building blocks, both of which were obtained by reduction of prochiral 1,3-diketones with baker's yeast. The key reactions are aldol condensation to introduce asymmetry at C-12 and -13 and reductive lactone cleavage followed by aldol-type condensation for c-ring formation.

ダイズシストセンチュウ（大豆包のう線虫）のふ化促進物質，グリシノエクレピンＡの単離研究をふりかえって

Some cyst-forming nematodes, such as potato cyst nematode (Globodera rostochiensis) and soybean cyst nematode (Heterodera glycines), are known as serious pests in agriculture. The eggs in these cysts remain dormant until hatching is stimulated by root exudates from host plants. Since the first discovery by Baunacke (1922) of this phenomenon for the potato cyst nematode, the isolation of the stimulus has been the object of considerable research. However, its extremely low concentration and relative instability have prevented its isolation.In this article, we describe how we have isolated the first hatching stimulus, glycinoeclepin A, from the dried roots of kidney bean (Phaseolus vulgaris), one of the host plants of the nematode. This substance is active at the concentration of 10-11-12g/ml in vitro against the soybean cyst nematode.

Glycinoeclepins B and C, nortriterpenes related to glycinoeclepin a

The structure of two new nortriterpenes, glycinoeclepins B and C, isolated from the aqueous extracts of roots of kidney bean and related structurally to glycinoeclepin A, a natural hatching stimulus for the soybean cyst nematode, has been elucidated to be formulas 2 and 3, respectively.

Glycinoeclepin A, a natural hatching stimulus for the soybean cyst nematode

A large-scale of isolation of glycinoeclepin A, a natural hatching stimulus for the soybean cyst nematode, and its structure elucidation by spectroscopic and X-ray methods are described.

Isolation of a natural hatching stimulus, glycinoeclepin A, for the soybean cyst nematode

The cyst nematodes (genera Heterodera, Globodera and others)1 generally have a limited host range. This specificity arises from the fact that the hatching of larvae from cysts occurs in response to specific stimuli secreted by the host plants2–4. Because of the scientific interest and importance in agriculture of these stimuli, since their first recognition5 in 1922 much time and effort2–4 has been expended in attempts to purify and characterize them. However, success has been limited by the extremely small amounts of active substance available. We report here the isolation of a natural hatching stimulus for the soybean cyst nematode from the roots of kidney bean. The substance, designated as glycinoeclepin A, stimulates the hatching of larvae from the eggs in vitro at a concentration of 10−11 to ∼10−12 g ml−1 in water at 25 °C.

Eggs of Floodwater Mosquitoes XII. Installment Hatching of Aedes vexans (Diptera: Culicidae)1

Eggs of Aedes vexans (Meigen) obtained from mosquitoes reared and conditioned under controlled conditions will hatch in toto when subjected to a terminal hatching stimulus of reduced oxygen. However, eggs in the field, or when brought to the laboratory from the field, will not respond equally to this hatching stimulus. It was the objective of this investigation to demonstrate that sequential temperatures, location of the eggs, and circadian regimens of light during the antecedent generation could result in erratic or installment hatching.

Studies of incubation and broody behaviour in the pheasant ( Phasianus colchicus

Evidence is presented which indicates that hen pheasants show responses other than incubation as incubation progresses. Some types of behaviour are observed only by hens in the advanced stages of incubation. Other responses may be detected throughout incubation. The development of this behaviour in the first half of incubation coincides with the rapid rise in the content of prolactin in the pituitary. Experimental reduction and prolongation of the incubation period yield data which suggest that prolactin has a conditioning effect on the brooding hen. Prior to this conditioning, a premature hatching stimulus does not elicit brooding behaviour in hens with no previous breeding experience. Delay of the hatching stimulus does not appear to affect chick acceptance. The typical behaviour of the pheasant cock to the incubating hen and the chicks is described. The few cocks which incubated eggs showed the same development of behaviour and broody activity which was observed in hens.

The Physiology of Hatching of Aedine Mosquito Eggs: Hatching Stimulus

By polarographic determination of the dissolved oxygen concentration of media used to flood eggs of Aedes aegypti and A. nigromaculis, the effect of dissolved oxygen in stimulating hatching was found to be twofold. An inverse relation occurred between dissolved oxygen and hatching of eggs flooded under conditions of static oxygen level, very low levels being required to induce a high degree of hatching. In contrast, even a slight lowering of the oxygen level while eggs were flooded proved a powerful hatching stimulus. A decline lasting several hours was found in the dissolved oxygen level at the soil-water interface of flooded soil, so that a decreasing level, rather merely a very low level, of dissolved oxygen seems to represent the natural mode of stimulation. Exposure of eggs to 50% relative humidity significantly reduced the hatching response as compared with that of eggs kept under high-humidity conditions.