Zofia Lassota

The activity of acetylcholinesterase during development of the moth, Celerio euphorbiae.

Abstract Acetylcholinesterase activity and acetylcholine content both increase during the growth of larvae and become inversely correlated in pharate pupae and emerged pupae. Dramatic changes of ACh and AChE occur in the abdomen during the first 8 days after the larval-pupal ecdysis and are sex-dependent and do not involve the central nervous system.

The effect of 20-hydroxyecdysone on expression of genes coding for low molecular weight silk proteins of Galleria mellonella

Abstract The low molecular weight Galleria silk proteins of 24 and 29–30 kDa are coded by the 1100 nucleotides long mRNAs of the posterior silk gland (PSG) cells. The synthesis of these proteins starts during the first 2 days of the last instar when the endogenous ecdysteroid titre is very low. The synthesis of 24 kDa protein precedes the synthesis of 30 kDa protein. PSGs from day 1 last instar larvae are sensitive to exogenous 20-hydroxyecdysone (20-HE) in vitro at 0.5 μg/ml concentration causing an increase of 1100 nucleotides long mRNAs. The electrophoretic analysis of the in vitro labelling proteins indicates that 20-HE may induced the synthesis of 30 kDa protein. Juvenile hormone II in vitro suppresses the stimulatory effect of 20-HE. PSGs from day 3 last instar larvae are insensitive to exogenous 20-HE in vitro .

Effect of spatial position of uterine quail blastoderms cultured in vitro on bilateral symmetry formation

SummaryA method of in vitro culture for uterine quail blastoderms has been developed, which allows them to develop from cleavage throughout gastrulation and further: stages 4–10 of Hamburger and Hamilton (1951). The method consists of cultivating the blastoderms on egg albumen in a vertical position; this permits about 50% of the blastoderms explanted before area pellucida formation to develop bilateral symmetry and to form normal primitive streak, somites and head structures. Development of the blastoderms explanted after their area pellucida was already formed, occurred normally and was not influenced by their spatial position in the culture.

Polyadenylated RNA in diapausing and developing embryos of Bombyx mori

Abstract The polysome fraction from diapausing embryos of Bombyx mori contains polyadenylated RNA which does not show messenger activity in vitro. The enhanced synthesis and polyadenylation of RNA during development of the embryo results in the appearance of active mRNA in polysomes.

Acetylcholinesterase in Celerio euphorbiae during pupal development with diapause

Abstract Striking changes in AChE activity and Ach content occur in the tissues of the abdomen of Celerio pupae during development with diapause. These changes are sex-dependent and unrelated to the nervous system. The pattern of changes is similar in development with and without diapause, but its correlation with the morphological changes in the central nervous system and lysis of the fat body differs for the two types of development.

Polysomes in diapausing and developing embryos of Bombyx mori

Abstract Particles sedimenting in a 12 to 36% sucrose gradient like polysomes were found in diapausing embryos of Bombyx mori . The predominance of heavy components and an unusually high protein content were characteristic for these “dormant” polysomes.

Choline and β-methylcholine acetylation in pupae of the moth, Celerio euphorbiae

Abstract Acetylation of choline and β-methylcholine in the tissues of Celerio euphorbiae was investigated during development after larval-pupal ecdysis in diapausing and non-diapausing generations. β-Methylcholine was acetylated more efficiently than choline. The stage- and sex-dependent changes in acetylating activity have been observed, their patterns being similar for both substrates. K + and Na + ions do not influence the specificity of the acetylation process.

Acetyl-β-methylcholine: The chief non-lipid choline derivative in Lepidoptera

Abstract The cholinergic substance present in large amounts in the tissues of Celerio euphorbiae and other Lepidoptera, and previously assumed to be acetylcholine, was identified by chromatographic, electrophoretic, and pharmacological tests as acetyl-β-methylcholine. In Celerio pupae and/or pharate adults acetyl-β-methylcholine occurs together with small amounts of acetylcholine. The possible metabolic role of acetyl-β-methylcholine in insects is discussed.

Brain factor fromGalleria mellonella (Lepidoptera) stimulating silk gland activity

Brain extracts from day 1–4 last instar larvae ofGalleria mellonella (Lepidoptera) stimulate RNA synthesis in cultured silk glands from day 3 last instar larvae. When the fibroin-synthesizing posterior parts of silk glands were incubated for 3 h in vitro in the presence of brain extract (0.1 brain equivalent), [3H]-uridine incorporation into RNA was stimulated more than twofold. The stimulating effect of brain extract showed a dose response relationship. It is suggested that the heat-resistant and protease-sensitive brain factor is a peptide.

Effect of hormones on acetylcholinesterase activity and RNA synthesis in diapausing Celerio euphorbiae pupae

Abstract Administration of either juvenile hormone (20 μg) or β-ecdysone (7.5 μg) to diapausing pupae of Celerio euphorbiae results in accelerated appearance of transitory acetylcholinesterase activity in abdominal tissues and in similarly accelerated eclosion of the moth. The enzyme activity, preceded by stimulation of RNA synthesis, appears within few hours after juvenile hormone injection whereas the activity induced by β-ecdysone is visible only after 3 days of hormone action.