Read e-book online Biology of Hydra PDF

By Allson Burnett (Eds.)

Show description

Read or Download Biology of Hydra PDF

Best biology books

Download e-book for kindle: The Biology of Seeds: Recent Research Advances by G Nicolas, K J Bradford, D Come, H W Pritchard

This ebook provides edited and revised papers from the 7th foreign Workshop on Seeds, held in Salamanca, Spain, in may possibly 2002. the foremost themes addressed contain seed improvement, germination and dormancy, in addition to desiccation, seed ecology and seed biotechnology.

Root Hairs: Cell and Molecular Biology - download pdf or read online

Root hairs are tip-growing cells that originate from epidennal cells referred to as trichoblasts. Their function will be easily regarded as extending the skin sector of the basis to facilitate absorption of food and water. notwithstanding, as you'll find during this e-book, the basis hair is much greater than that. To an more and more higher variety of plant biologists, the foundation hair is a version phone.

Read e-book online Advances in Enzymology and Related Areas of Molecular PDF

Advances in Enzymology and comparable components of Molecular Biology is a seminal sequence within the box of biochemistry, delivering researchers entry to authoritative studies of the newest discoveries in all parts of enzymology and molecular biology. those landmark volumes date again to 1941, offering an unequalled view of the ancient improvement of enzymology.

Additional resources for Biology of Hydra

Example text

1963) suggest that substances other than GSH (for example, trypsin), which induce mouth opening in Hydra, operate through a mechanism of inducing nematocyst discharge. They postulated that the feeding stimulator, possibly G S H , is present in the nematocyst capsule and is released on discharge. H. M. Lenhoff (1968a) established that trypsin did not initiate mouth opening by causing nematocyst discharge, thereby releasing GSH into the medium. The clarifying experiment utilized the pH optimum curves for glutathione (broadly, from 4 to 8), and for trypsin (restricted to around pH 6).

RUSHFORTH position for one or two minutes before contracting again, repeating the cycle of activity. " He observed that such activity was more frequent in hungry Hydra, a finding not substantiated by later investigators (Passano and McCullough, 1964; Rushforth and Hofman, 1972). In a series of studies, Reis (1946a,b,c) described factors affecting the frequency of contractions and extensions in Pelmatohydra oligactis {Hydra oligactis). He found that the variable temporal and spatial patterns of extensions in the animal were more frequent when food was present in the gut, but were not affected by the presence of attached buds.

IV. Response to External Stimulation The previous sections of this chapter described relatively complex behavioral sequences of locomotion and feeding in Hydra. The range of such behavior appears quite wide, particularly since coelenterates are often thought of as simple sessile animals, not having a rich spectrum of activities. The effects of chemostimulation, in the form of reduced glutathione, in initiating various components of the feeding response have been described in some detail. This section will consider the responses of Hydra to other forms of stimulation.

Download PDF sample

Rated 4.05 of 5 – based on 12 votes