Nature et faune : revue internationale pour la conservation de la nature en Afrique = Wildlife and nature : international journal on nature conservation in Africa.

2.3-4

Nature et faune : revue internationale pour la conservation de la nature en Afrique = Wildlife and nature : international journal on nature conservation in Africa.

6.4

Nature et faune : revue internationale pour la conservation de la nature en Afrique = Wildlife and nature : international journal on nature conservation in Africa.

21.2

Some observations on the biology and morphology of the immature stages of Psychodopygus wellcomei fraiha, shaw and lainson, 1971: (Diptera: psychodidae)

Under laboratory conditions, the development from egg to adult of P. wellcomei takes an average of 42 days. The larval tages are similar to those of P. arthuri, described by barretto (1941), but can be distinguished from this species by the ratio of the first to second antennal segment, by the form of the lateral head seate and prothoracic dorsolateral setae. The pupal stage of P. wellcomei is characterized by a trifid pre-alar seta and simple spine-like thoracic and abdominal setae.

Thymulin: biochemistry, biology and therapeutical applications

Thymulin is a pharmacologically active metallononapeptide inducing the differentiation of T cells and enhancing several functions of the various T cell subsets in normal or partially thymus-deficient recipients. Its effect on suppressor T cells is, so far, the most remarkable and should be the first to find useful clinical applications. The peptide is a natural hormone, available in synthetic form. It is not toxic and one may foresee its clinical use as one of the major immunoregulatory agents in the near future.

The cell biology of mosquito vitellogenesis

Insect vitellogenesis involves coordinated activities of the fat body and oocytes. We have studied these activities at the cellular level in the mosquito. During each vitellogenic cycle, the fat body undergoes three successive stages: 1) proliferation of biosynthetic organelles, 2) vitellogenin synthesis, 3) termination of vitellogenin synthesis and degradation of biosynthetic organelles by lysosomes. Analysis with monoclonal antibodies and radiolabelling demonstrated that the mosquito yolk protein consists of two subunits (200-kDa and 65-kDa). Both subunits are glycosylated, their carbohydrate moieties are composed of high-mannose oligosaccharides. The yolk protein subunits are derived from a single 220 kDa precursor detected by an in vitro translation. Oocytes become competent to internalize proteins as a result of juvenile hormone-mediated biogenesis of endocytotic organelles. The yolk protein is then accumulated by receptor-mediated endocytosis. A pathway of the yold protein and factors determining its routing in the oocyte have been studied.