Antiproliferative activity of Humulus lupulus extracts on human hepatoma (Hep3B), colon (HT-29) cancer cells and proteases,tyrosinase, β-lactamase enzyme inhibition studies

The aims of this study were to examine the antiproliferation of Humulus lupulus extracts on human hepatoma carcinoma (Hep3B) and human colon carcinoma (HT-29) cell lines along with enzyme inhibitory effects of the crude extracts. Potential cell cytotoxicity of six different H. lupulus extracts were assayed on various cancer cells using MTT assay at 24, 48 and 72?h intervals. Methanol-1 extract has inhibited the cell proliferation with doses of 0.6–1?mg/mL in a time dependent (48 and 72 hours) manner in Hep3B cells with 70% inhibition, while inhibitory effect was not seen in colon cancer cells. Acetone extract has increased the cell proliferation at low doses of 0.1?mg/mL for 72?h in Hep3B cells and 0.1–0.2?mg/mL for 48 and 72?h in HT29 cells. The inhibitory effects of the extracts were compared by relative maximum activity values (V_max) using proteases such as α-chymotrypsin, trypsin and papain, tyrosinase and β-lactamase (penicillinase).     

Effects of long-term exposure to 900 megahertz electromagnetic field on heart morphology and biochemistry of male adolescent rats

The pathological effects of exposure to an electromagnetic field (EMF) during adolescence may be greater than those in adulthood. We investigated the effects of exposure to 900 MHz EMF during adolescence on male adult rats. Twenty-four 21-day-old male rats were divided into three equal groups: control (Cont-Gr), sham (Shm-Gr) and EMF-exposed (EMF-Gr). EMF-Gr rats were placed in an EMF exposure cage (Plexiglas cage) for 1 h/day between postnatal days 21 and 59 and exposed to 900 MHz EMF. Shm-Gr rats were placed inside the Plexiglas cage under the same conditions and for the same duration, but were not exposed to EMF. All animals were sacrificed on postnatal day 60 and the hearts were extracted for microscopic and biochemical analyses. Biochemical analysis showed increased levels of malondialdehyde and superoxide dismutase, and reduced glutathione and catalase levels in EMF-Gr compared to Cont-Gr animals. Hematoxylin and eosin stained sections from EMF-Gr animals exhibited structural changes and capillary congestion in the myocardium. The percentage of apoptotic myocardial cells in EMF-Gr was higher than in either Shm-Gr or Cont-Gr animals. Transmission electron microscopy of myocardial cells of EMF-Gr animals showed altered structure of Z bands, decreased myofilaments and pronounced vacuolization. We found that exposure of male rats to 900 MHz EMF for 1 h/day during adolescence caused oxidative stress, which caused structural alteration of male adolescent rat heart tissue.     

Oral vitamin C and E combination modulates blood lipid peroxidation and antioxidant vitamin levels in maximal exercising basketball players

Oxidative stress occurs during maximal exercise, perhaps as a result of increased consumption of oxygen. Vitamins C and E can overcome the effects of antioxidants in exercise. We investigated the effects of supplementation with a combination of vitamin C and E (VCE) on blood lipid peroxidation (LP) and antioxidant levels following maximal training in basketball players. Blood samples were taken from 14 players (group A) and divided into two subgroups namely maximal training (group B) and maximal training plus VCE groups (group C). Group B maximally exercised for 35 days. VCE was supplemented to group C for 35 days and blood samples were taken from group B and C. Plasma and hemolyzed erythrocyte samples were obtained from the players. Erythrocyte glutathione peroxidase (GSH‐Px) activity and plasma vitamin E concentration were lower in group B than in group A, whereas plasma and erythrocyte LP levels were higher in group B than in group A. Plasma vitamin A, vitamin E, erythrocyte GSH‐Px, and reduced glutathione (GSH) values were higher in group C than in groups A and B although LP levels in plasma and erythrocytes were lower in group C than in group A and B. β‐Carotene values did not change in the three groups. In conclusion, VCE supplementation in maximal exercising basketball players may strengthen the antioxidant defense system by decreasing reactive oxygen species (ROS). Copyright © 2010 John Wiley & Sons, Ltd.     

Aphid–ant mutualism: how honeydew sugars influence the behaviour of ant scouts

Honeydew is the keystone on which ant–aphid mutualism is built. The present study investigates how each sugar identified in Aphis fabae Scopoli honeydew acts upon the feeding and the laying of a recruitment trail by scouts of the aphid‐tending ant Lasius niger Linnaeus, and thus may enhance collective exploitation by the ant mutualists. The feeding preferences shown by L. niger for honeydew sugars are: melezitose = sucrose = raffinose > glucose = fructose > maltose = trehalose = melibiose = xylose. Although feeding is a prerequisite to the launching of trail recruitment, the reverse is not necessarily true: not all ingested sugar solutions elicit a trail‐laying behaviour among fed scouts. Trail mark laying is only triggered by raffinose, sucrose or melezitose, with the latter sugar being specific to honeydew. By comparing gustatory and recruitment responses of ant foragers to sugar food sources, the present study clarifies the role of honeydew composition both as a source of energy and as a mediator in ant–aphid interactions. Lasius niger feeding preferences can be related to the physiological suitability of each sugar (i.e. their detection by gustatory receptors as well as their ability to be digested and converted into energy). Regarding recruitment, the aphid‐synthesized oligosaccharide (melezitose) could be used by ant scouts as a cue indicative of a long‐lasting productive resource that is worthy of collective exploitation and defence against competitors or aphid predators.     

Ant cues affect the oviposition behaviour of fruit flies (Diptera: Tephritidae) in Africa

Abstract. Although most studies on fruit fly oviposition behaviour focus on horizontal interactions with competitors and cues from host plants, vertical interactions with predators are poorly documented. The present study provides direct evidence indicating that the oviposition behaviour of the two main mango fruit fly species, Ceratitis cosyra (Walker) and Bactrocera invadens Drew‐Tsurata & White, is affected by secretions of the dominant arboreal ant Oecophylla longinoda (Latreille). When offered ant‐exposed and unexposed mangoes in the absence of the ants, both fly species are reluctant to land on ant‐exposed fruits and, when having landed, often take off quickly and fail to oviposit. The number of puparia collected from unexposed mangoes is approximately eight‐fold higher than from ant‐exposed ones. The results obtained from laboratory experiments and field observations confirm that adult fruit flies are more affected through repellence by ant cues than by direct predation. The use of cues by fruit flies in predator avoidance has implications for evolutionary ecology, behavioural ecology and chemical ecology.     

Phylogeny and biogeography Eupholidoptera Mařan (Orthoptera,Tettigoniidae): morphological speciation in correlation with the geographical evolution of the eastern Mediterranean

Recently, the systematics and biogeography of the Mediterranean biota have received much attention. This paper deals with Eupholidoptera Ma?an, a Mediterranean lineage of Tettigoniidae. The genus is restricted to the northern and eastern basin of the Mediterranean, with a significant number of species found on the Aegean islands. To produce a phylogeny and use it to make assumptions about the historical biogeography of Eupholidoptera, material of 46 species from several collections was studied. A phylogenetic analysis based mainly on morphological characters suggested two lineages in the genus: the E. chabrieri and the E. prasina groups. Based on the consistency between historical geographical events and branching events on the phylogenetic tree, Eupholidoptera is assumed to have evolved from an ancestor present in the Aegeid plate in the Mid‐Miocene. The division of the Aegeid plate into Anatolia and Greece in the Tortonian, the reoccurrence of terrestrial corridors between these mainlands in the Messinian, the regression of the Aegean area in the Pliocene and sea level changes in the Pleistocene are assumed to have been the main palaeogeographical events directing speciation in Eupholidoptera. As most of the species are allopatric, vicariance is suggested to be the main pattern. By combining the nature of the characters used in the phylogenetic analysis, the phylogenetic tree produced and the biogeographical assumptions, four tentative conclusions can be made: (i) radiation in the genus is a result of divergence in morphology; (ii) because the main character source is male genitalia, there has possibly been intensive sexual selection, which leads to morphological speciation; (iii) as the difference in temporal parameters of the song is prominent in sympatric/parapatric species pairs only, co‐occurrence is suggested to be the main reason driving divergence in the song; (iv) there seems to be a negative correlation between the size of the distribution range and the evolutionary rate in speciation; this may be the reason why the E. prasina group (restricted to a small part of the range of the genus) is more diverse than the E. chabrieri group, which is distributed over the entire range.     

Immobilized Growth of the Peridinin-Producing Marine Dinoflagellate Symbiodinium in a Simple Biofilm Photobioreactor

Products from phototrophic dinoflagellates such as toxins or pigments are potentially important for applications in the biomedical sciences, especially in drug development. However, the technical cultivation of these organisms is often problematic due to their sensitivity to hydrodynamic (shear) stress that is a characteristic of suspension-based closed photobioreactors (PBRs). It is thus often thought that most species of dinoflagellates are non-cultivable at a technical scale. Recent advances in the development of biofilm PBRs that rely on immobilization of microalgae may hold potential to circumvent this major technical problem in dinoflagellate cultivation. In the present study, the dinoflagellate Symbiodinium voratum was grown immobilized on a Twin-Layer PBR for isolation of the carotenoid peridinin, an anti-cancerogenic compound. Biomass productivities ranged from 1.0 to 11.0 g m^?2 day^?1 dry matter per vertical growth surface and a maximal biomass yield of 114.5 g m^?2, depending on light intensity, supplementary CO₂, and type of substrate (paper or polycarbonate membrane) used. Compared to a suspension culture, the performance of the Twin-Layer PBRs exhibited significantly higher growth rates and maximal biomass yield. In the Twin-Layer PBR a maximal peridinin productivity of 24 mg m^?2 day^?1 was determined at a light intensity of 74 μmol m^?2 s^?1, although the highest peridinin content per dry weight (1.7 % w/w) was attained at lower light intensities. The results demonstrate that a biofilm-based PBR that minimizes hydrodynamic shear forces is applicable to technical-scale cultivation of dinoflagellates and may foster biotechnological applications of these abundant marine protists.