the leaf nitrogen content is generally accepted as an indicator of food quality and as a factor affecting host selection by phytophagous insects. the alate pea aphids (acyrthosiphon pisum harris, aphididae) were given a choice among non-nodulated pea plants (pisum sativum l.) supplied with one of four nitrate-n levels (0, 3, 15 and 30 mm). when whole plants were exposed to aphids for 7 days, th...

Background: Intracytoplasmic sperm injection (ICSI) can be considered the solstice in vitro insemination technique because it has powerfully allowed the treatment of male factor infertility, but in this procedure, except visual morphological selection, there is no standardization for sperm selection. Recently, hypo osmotic swelling test (HOST) has been proposed to have the potential to select i...

Background: During ICSI, motile sperm with normal morphology are selected and injected into oocyte. But integrity of chromatin is not observable. Therefore, researchers are trying for to present novel method of sperm selection with high percentage of normal chromatin. HOST test is a useful assay of functional integrity of the human sperm membrane. We decide to use HOST test after DGC for infert...

A rapid DNA cloning system is a research interest of many scientists. TA cloning is one of the methods used for the cloning of PCR-amplified DNA molecules. The TA cloning method is a convenient and labor-saving replacement to traditional, restriction enzyme-mediated cloning strategies. A T-vector called pBlueskript ΙΙ SK-1 with the lethal gene ccdB was designed to construct a positive selection...

Host plant selection by insects is often divided into „host plant finding‟ and „host plant acceptance.‟ While the two are easy to separate conceptually, in practice, they are really part of a continuum of three, rather than two, inextricably bonded links. However, the central link of host plant finding, thought previously to be governed by volatile chemicals, has, until now, proved intractable ...