Larva hybridization

In addition to the unique and quite dramatic differences in feeding/survival of larvae of the P. glaucus complex and their hybrids (2 0) (Table III), tulip tree and quaking aspen represent phytochemically intriguing foodplants for several other North... 

In our experiments, black cutworm (Agrotls Ipsllon) (BCT7) larvae were fed corn seedlings and artificial diet. While there appear to be species of plants that are even more susceptible to BCTJ larvae than com, corn was not statistically different from the most susceptible species tested by Buschlng and Turpin (52), and certainly BCW can occasionally be extremely damaging to corn. Further, Wilson et al. (53), Tseng et al. (54), and Jarvis et al. (55) have screened thousands of maize introductions, inbred lines, and hybrids, and have found only a very few sources of even moderate resistance. 

Vines wilt suddenly. Cause Squash vine borers. These fat, white, 1" long larvae burrow into the stems and exude masses of yellow-green, sawdustlike excrement. For an illustration of this pest, see page 214. Slit stems lengthwise above injury with a sharp knife and kill larvae. Cover cut stems with moist soil so they will form new roots. Injecting stems with BTK or parasitic nematodes may also control borers. To reduce problems, plant the cultivar Sweet Mama Hybrid , which is resistant to vine borers. Or spray base of stems with BTK once a week in late spring and early summer. 

Tomatidine (298) was found to be a feeding deterrent to sixth instar larvae of the spruce budworm Choristoneura fumiferana [658] and it strongly inhibited growth in the Xenopus embryo teratogenesis assay [651]. The 3-oxo derivative of 298, and the 23-acetoxy derivative have been isolated from roots of a hybrid of Lycopersicon esculentum x L hirsutum [640],... 

Haygood, M.G. and Davidson, S.K. (1997) Small-subunit rRNA genes and in situ hybridization with oligonucleotides specific for the bacterial symbionts in the larvae of the bryozoan Bugula neritina and proposal of Candidatus endobugula sertula . Appl. Environ. Microbiol. 63 4612-4616. 

Figure.6 Dot-blot hybridizations of a labeled DNA sequence that is highly repetitive in Onchocerca volvulus and specific for that species to DNA of infections of black flies from two localities in Cameroon (Campement du Syrien lanes A and B Wakwa Lane C). The parasitic larvae used are indicated on the left side (e.g. 3 L3 means 3 third stage larvae were blotted). The corresponding hybridization pattern is shown on the right side. Only 6 larvae proved to be O. volvulus.

Unlike 2-tridecanone-mediated resistance, which is inherited recessively (45) and kills early instar larvae, the lameliar-based resistance is a dominant or incompletely dominant character. Its presence is observed when larvae are fed PI 134417 foliage from which glandular trichomes have been removed, or Fi hybrid (L, esculentum x PI 134417) foliage, which does not possess 2-tridecanone-mediated resistance (52),... 

In field cage studies in which zea larvae on several plant lines were exposed to adult parasitoids (one plant line per cage), percent paras itization by both species was significantly lower on BC2, (a backcross ((L, esculentum x PI 134417) x PI 134417) line with intermediate levels of 2-tridecanone and glandular trichome density), and PI 134417 than on L. esculentum and the Fi hybrid (L. esculentum X PI 134417) (Table ViTT. This pattern reflects levels of 2-tridecanone-mediated resistance to sexta. These data indicate that fewer zea larvae are parasitized on the more resistant plant lines but do not indicate whether this is due to elevated densities of glandular trichomes or methyl ketones, or both. 

The question, whether the discrepancy between the rDNA values for brain and liver tissues of the rat is the result of technical errors or represents true rDNA amplification, has been answered unequivocally by Mohan et al. (1969). Cross-hybridization between rRNA and DNA from rat liver and brain in all combinations resulted in identical saturation plateaus within the limits of measurement. This result clearly indicates that rDNA amplification does not take place in rat brain tissue. Furthermore, Ryffel et al. (1973) have shown that the number of rRNA genes remains unchanged in liver and tail muscle of Xenopus laevis larvae during thyroxine-induced metamorphosis, although the synthesis of rRNA is increased in larval tissues in response to hormone treatment. This observation casts some doubt on the validity of the interpretation by Koeh and Cruceanu (1971), especially because they used exceedingly high concentrations of the hormone. 

Plants containing demissin are not affected by the larva of the potato beetle 29). This doubtlessly arises from the presence of the alkaloid, since, normally, potato leaves are avoided when they have a gelatinous layer containing demissin. Crossbreeding between species containing solanin and demissin does not lead to the expected resistance, because the demissin content decreases in the hybridization 31). 

Specific whole-mount ISH protocols for the embryos, larvae, or small pieces of tissue of a number of other organisms have been published, including Xeno-pus (4,5), sea urchin (6,7), zebrafish (8), Drosophila (9), chicken (10,11), axolotl (12), and the leech (13). Protocols for the simultaneous hybridization and subsequent detection of two probes with different nonradioactive labels are also available (14,15). 

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