AN APPARATUS FOR EXCHANGING DIETS RAPIDLY DURING ARTIFICIAL FEEDING OF SUCKING INSECTS

1977 ◽  
Vol 109 (1) ◽  
pp. 15-20 ◽  
Author(s):  
W. G. Friend ◽  
J. J. B. Smith

AbstractAn apparatus is described which permits either continuous or interrupted flow of diet under a membrane through which piercing and sucking insects can feed. The flow does not affect feeding behaviour while allowing a replacement of one diet by another which is 99% effective in less than 2 sec, using approximately 2 ml of diet. Monitoring electrical conductivity of a diet at the feeding membrane permits quantitative evaluation of exchange efficiency. Use of this apparatus in experiments on dietary requirements and mass-rearing are discussed.

2020 ◽  
Vol 30 (0) ◽  
pp. 115-118
Author(s):  
Kazuyuki HIGASHI ◽  
Shuji KAWAKAMI ◽  
Juri NAKASHIMA ◽  
Minoru FUJISAKI ◽  
Mamoru NISHIOKA

1980 ◽  
Vol 58 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Timothy K. Twongo

Development of feeding behaviour in young rainbow trout, Salmo gairdneri, from "swim-up" to day 57 after hatch at 8.5 °C is described relative to food type (live Artemia salina or dry trout ration) and water flow (current or no current). Earliest signs of feeding behaviour appear during the process of swim-up at days 27 to 29, with the movement of the eyes to fixate particles and the beginning of a snap response which intensifies within 2 days. Initially the alevins are nonselective between food and inert targets, but by about day 25 at the test temperature they have become able to discriminate food from nonfood items, and show a marked increase in exogenous feeding activity. The timing, which will differ at different rearing temperatures, coincides approximately with final absorption of the visible yolk sac and follows disappearance of the oesophageal plug by about 10 days. This would seem to be the best time to initiate artificial feeding of hatchery-reared alevins, with the fish showing a preference for ingestion of live food (shrimp nauplii) over dry rations. Despite evident behavioural differences in current and no-current conditions this factor had little effect on timing or ultimate success of first feeding. Failure of some alevins to begin feeding, or feed adequately for survival, is associated with the agonistic behaviour of more aggressive siblings.


Author(s):  
John C. Russ ◽  
Nicholas C. Barbi

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.


Author(s):  
Klaus-Ruediger Peters ◽  
Samuel A. Green

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.


Physica ◽  
1952 ◽  
Vol 18 (2) ◽  
pp. 1147-1150
Author(s):  
D MAEDER ◽  
V WINTERSTEIGER

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