Entomotoxic action of Sambucus nigra agglutinin i in Acyrthosiphon pisum aphids and Spodoptera exigua caterpillars through caspase‐3‐like‐dependent apoptosis

In this project, the toxicity and mechanism of action of the ricin‐B‐related lectin SNA‐I from elderberry (Sambucus nigra) in the pea aphid (Acyrthosiphon pisum) and the beet armyworm (Spodoptera exigua), two important pest insects in agriculture, were studied. SNA‐I is a chimeric lectin belonging to the class of ribosome‐inactivating proteins and consists of an A‐chain with N‐glycosidase activity and a carbohydrate‐binding B‐chain. Incorporation of 2 mg/ml of SNA‐I in the diet of neonates and adults of A. pisum caused 40–46% mortality within 2 days, while in third instars of S. exigua, the larval biomass was significantly reduced by 12% after feeding for 3 days on a diet containing 5 mg/g of SNA‐I. Interestingly, extracts of the (mid)gut of treated A. pisum and S. exigua demonstrated DNA fragmentation and this was accompanied with an increase in caspase‐3‐like activity. The involvement of cell death or apoptosis in the entomotoxicity of SNA‐I through induction of caspase‐3‐like activity was also confirmed by addition of the permeable caspase‐3 inhibitor III in the diet, leading to a rescue of the treated aphid neonates. Finally, similar to the chimeric lectin SNA‐I, the hololectin SNA‐II, consisting of two carbohydrate‐binding B‐chains caused high mortality to neonate A. pisum aphids with an LC₅₀ of 1.59 mg/ml, suggesting that the entomotoxic action of the lectins under study mainly relies on their carbohydrate‐binding activity. © 2010 Wiley Periodicals, Inc.     

Strong increase in hepatic and blood histamine levels after partial hepatectomy in rats]

The histamine rates, when established by fluorometry, according to the method of Shore, in the residual liver and in the whole blood of Wistar-Commentry male rats, quickly increase after partial hepatectomy carried out as described by Higgins and Anderson. The levels reach a peak 24 h after hepatectomy, then progressively lower, and on the 4th day are almost equal to the rates of control or sham operated animals.     

Fluctuations of Feulgen- and diphenylamine-DNA in peripheral leukocytes

The circulating leukocyte is usually considered a mature, differentiated cell which does not normally divide. Cytophotometry of human and mouse leukocyte nuclei, however, reveals significant fluctuations in amounts of Feulgen-DNA in all leukocytes at various times of the day. When analyzed for DNA content by the diphenylamine method, the same samples demonstrate variations closely correlated with those obtained by cytophotometry. Although these data may be interpreted as suggesting, among other things, the presence of metabolic DNA, a preliminary radioautographic study of the uptake of tritiated thymidine in mouse leukocytes failed to demonstrate evidence of DNA synthesis in the entire population of cells. In this study only 6–7% of the total leukocyte population was labelled over a 24-hour period. This discrepancy, when considered in light of other uncertainties concerning the Feulgen and diphenylamine reactions, has led to reservations over the ability of either reaction to reflect the true amount of DNA in cells at all times. Rather, we consider it more likely that both procedures reveal similar incomplete fractions of leukocyte DNA at various times of the day, and that the magnitude of this fraction is, perhaps, determined by cyclic influences acting on such parameters as nuclear volume and degree of packing of the nucleohistones.     

V.A.T.E.R. association and its limits

Comparative investigation of 92 cases of V.A.T.E.R. syndrome (4 personal cases) and 62 cases of caudal regression (Duhamel syndrome) (2 personal cases) are performed. There is much analogy between these two entities. Initial impairment would be an early dysfunction of mesoderm setting up located on esophagus in V.A.T.E.R. syndrome and on kidneys in Duhamel syndrome. Etiopathogenic factors remain unknown. Genetic counseling is good. Detection of only one mesodermal malformation leads to inquire other unnoticed anomalies (kidneys, heart, spine, alimentary duct).