Comparative effects of dimethylbenz(a)anthacene and a 15% olive-oil diet on cellular components and expression of apoptosis-related proteins in the spleen and mammary gland tumors of rats.

We compared effects of a high fat diet and a carcinogen on cellular elements of the spleen and mammary gland tumors in rats. Animals were fed a 15% olive-oil diet and a group of them were exposed to a carcinogen, dimethylbenz(a)anthacene (DMBA), in two doses of 10 mg/rat. Results of the experiments were evaluated after 4 months. We studied changes in the areas of different zones of the spleen related to production of B and T lymphocytes and also the number of cells in the spleen and tumors with positive reaction to receptors related to manifestation of apoptosis (FasL and p53) and receptors related to inhibition of apoptosis (bcl-2). In the spleen, dietary fats as well as DMBA alone decreased the zones related to production of B lymphocytes and increased the number of T lymphocytes. The combined effect of a carcinogen and a high fat diet manifested in an increase in the number of lymphoid cells and macrophages. In tumors from rats fed a low-fat diet, an extremely high number of lymphoid cells was seen in the border of tumors with T cell killers as a main component of these infiltrates. In tumors from rats fed a 15% olive-oil diet, the main component of the infiltrates were macrophages. High levels of p53+ and bcl-2+ cells were found in the spleen of rats exposed to a carcinogen. The combined effect of a carcinogen and the 15% olive-oil diet inhibited production of FasL and p53 receptors and stimulated synthesis of bcl-2 protein. In tumors, a carcinogen alone stimulated the high expression of FasL and p53 proteins, but in combination with the 15% olive-oil diet synthesis of these receptors decreased while production of bcl-2 protein increased sharply. This observation may serve as an additional proof of tumor-promoter effects of a high fat diet.

Transplacental effects of a 15% olive-oil diet on chemically-induced tumorigenesis in offspring.

We evaluated whether feeding pregnant female rats a diet high in olive-oil, that showed a tumor-preventive effect in adults, has a similar preventive effect on chemically-induced cancer in offspring (i.e. mammary glands and colon cancer in rats). The control group was fed the same 7% corn-oil diet as their mothers. Experimental group I was fed a 7% corn-oil diet while their mothers received a 15% olive-oil diet. Experimental group II was fed the same 15% olive-oil diet as their mothers. Female offspring were twice administered 7,12-dimethylbenz(a)antracene (DMBA) in doses of 10 mg/rat. Male offspring were injected 6 times with 1, 2-dimethylhydrazine (DMH) in doses of 20 mg/kg body weight. Effect of DMBA was manifested in a high rate of tumorigenesis: the number of tumor-bearing rats in control offspring reached 52.0%. This effect increased to 60.6% among offspring of experimental group II and to 67.7% in offspring of experimental group I. The mean tumor size increased significantly in control offspring. Following administration of DMH number of tumor-bearing rats was similar in all groups of offspring: 36.7%, 40.7% and 42.8%. Tumor types differed: the majority of tumors in the control group were benign polyps and adenomas (72.1%) and the number of adenocarcinomas was low (27.9%). The number of malignant tumors increased to 37.5% in offspring of experimental group II and to 45.5% in offspring of experimental group I. In control group offspring, a distinct tendency to increased body weight and a significant increase in spleen weight were seen. The findings indicate that feeding mothers a diet high in fat concentrations, even those with known tumor preventive significance in adults, lose this cancer-inhibiting role in offspring.

Evidence for volatile chemical attractants in the beetleMaladera matrida argaman (Coleoptera: Scarabaeidae).

TheMaladera matrida beetle (Coleoptera, Scarabaeidae, Melolonthinae), a relatively new species to science, was first identified in Israel in 1983. In the course of field observations it was found that adultM. matrida beetles emerged from the soil at sunset to feed and mate. During the first 20 min of flight, most of the beetles were males. The females emerged shortly afterwards, and aggregations numbering 20-30 individuals with equal proportions of males and females were eventually formed on peanut plants. Laboratory olfactometer bioassays showed that peanut leaves (food) attracted both males and females. Field-trapping experiments and olfactometer studies showed thatM. matrida beetles were highly attracted by live virgin females in the presence of food (cut-up peanut leaves). Another set of field trapping experiments indicated that airborne volatiles produced by live virgin females plus food had the same attracting ability as live virgin females plus food. The attraction exerted by the combination of live virgin females and peanut leave volatiles suggests a synergism effect. Accordingly, we propose a two-stage mechanism of chemical communication in theM. matrida beetles: first, the males cause mechanical damage to the host plant to attract both sexes; later, the females emit attractants (sex pheromone) while eating or shortly thereafter.

(Z,E)-alpha-farnesene--an electroantennogram-active component of Maladera matrida volatiles.

It has previously been shown in field-trapping experiments and laboratory olfactometer bioassays that virgin females of Maladera matrida Argaman (Coleoptera, Scarabaeidae) and their volatiles, both in the presence of food (cut peanut leaves), are efficient attractants for M. matrida males and females. In this study GC-EAD experiments using male antennae and GC-MS experiments revealed that (Z,E)-alpha-farnesene is an active component of M. matrida female volatiles. The identification and quantitive electrophysiological responses (EAG) of synthetic (Z,E)-alpha-farnesene were obtained with male and female antennae. It was also shown that (Z,E)-alpha-farnesene is not a component of the plant volatiles that serve as synergistic components of the mixture of attractants or of the source of food for M. matrida.