Abstract Multiple studies have focused on the environmental damage done by invasive species and highlighted them as a major threat to biodiversity. Invasive species can completely eliminate some native species. On the other hand, the invasion potential of alien species is strongly influenced by abiotic factors. Taking these factors into consideration, the present study has focused on the competitive interaction between an invasive freshwater pulmonate snail Physella acuta Draparnaud, 1805 (Gastropoda: Physidae) and sympatrically occurring Racesina luteola Lamarck, 1822 (Gastropoda: Lymnaeidae) in India. Competitive superiority of the exotic species was assessed by comparing the reproductive output of the invasive and indigenous species subjected to interactions observed in a community. To investigate the role of temperature as a driving force of the competitive superiority of the invasive snail, 4 temperatures were considered. At all temperatures, the invasive snail P. acuta deposited more egg clutches per individual than the native snail R. luteola did, irrespective of the interaction types. The reproductive output of both species increased with the gradual increase in temperature up to 30°C. At 35°C, the production of egg capsules (clutches) per individual and eggs per individual again decreased for both species. Their reproductive output was the highest at 30°C, while at 20°C, R. luteola laid lower numbers of egg clutches and eggs per individual when kept with P. acuta than when living with conspecifics only. This study shows that temperature can strongly affect the outcome of competition between invasive and indigenous species.
Abstract Inflammation is the immune system’s response to infection and injury. Although it is a natural and beneficial process, it has been implicated in the pathogeneses of arthritis, cancer, neurodegenerative, and cardiovascular disease. In this study, we evaluated the in vitro anti-inflammatory activity of the alcohol and aqueous extracts of marine gastropods Pachymelania aurita and Tympanotonos fuscatus (syn. Tympanotonus fuscatus) var. radula in peritoneal macrophage cells treated with lipopolysaccharide. Peripheral macrophages were harvested from mice following the injection of foetal calf serum into the peritoneal space. The cytotoxicity of the extracts on the macrophages and the maximum non-toxic dose was determined using the MTT assay. Cells were challenged with lipopolysaccharide and treated with crude extracts of T. fuscatus and P. aurita 24 h later. The antioxidant activity was also evaluated, using the DPPH assay. Both extracts of P. aurita and T. fuscatus exhibited significant anti-inflammatory activities in terms of their ability to inhibit the production of NO, TNF-α, IL-1 and PGE2, which are key mediators of the inflammation response. Also, the alcohol extracts proved to be as effective as vitamin C in the free radical scavenging of DPPH. Thus, the extracts from P. aurita and T. fuscatus are useful candidates for further drug studies, especially as drug candidates for the treatment of inflammatory conditions.
Abstract Lactobacillus brevis PCM 2570 is a strain of lactic acid bacteria, i.e. probiotic bacteria whose major fermentation product is lactic acid. The efficiency of lactic acid production is limited by the value of ambient pH. This study aimed to increase the survival of this bacterial strain at a reduced pH (3.9), which would result in an increased yield of lactic acid fermentation. In our experiment the survival rate of probiotic bacteria L. brevis PCM 2570 was increased 1.2-fold to 6.96-fold due to the presence of Fe3O4 magnetic nanoparticles, as compared to the control. The minimum concentration of nanoparticles with a positive effect was 8 mg/ml, but the optimum concentration was 20 mg/ml.
Abstract To investigate powdery mildew resistance in rye (Secale cereale), 397 inbred lines of winter rye were tested for susceptibility to infection with Blumeria graminis f. sp. secalis. The 50 most tolerant lines and 50 most infected lines were chosen for comparison. They were next tested for the presence of 4 markers linked to 4 alleles for resistance to powdery mildew, identified earlier in common wheat (Triticum aestivum). We found Pm3a only in 3 susceptible genotypes of winter rye, although this marker is linked to the powdery mildew resistance gene in wheat. The other 3 markers linked to Blumeria graminis f. sp. secalis resistance genes (Pm3b, Pm3c, Pm3d) were found in neither resistant nor susceptible rye genotypes.
Abstract Based on length, weight, and age data, we examined allometry and growth parameters for common pandora, Pagellus erythrinus, commercially collected seasonally from northern and southern Tunisian coasts in 2007. A total of 370 specimens (14–27.5 cm in length) were used to assess the allometric variation at seasonal scales. The slope b values (regression coefficient) of the length-weight relationship varied between 2.494 to 3.237, indicating (roughly) an isometric to negative allometric growth pattern. The allometric relationship, as a proxy for fish condition, seems to be affected by seasons and sex in the northern population, while only seasons seem to have a strong effect in the southern population, as indicated by ANOVA. The von Bertalanffy growth parameters were identified at L ∞ = 34.076 and 28.017 cm, k = 0.153 and 0.150/year, and t 0 = −1.922 and −3.961 years for the northern and southern sample, respectively.
