Intraspecific morphological variation of the sperm storing organ in two hermaphroditic land snail species

Green Seaweeds as a Potential Source of Biomolecules and Bioactive Peptides: Recent Progress and Applications - A Review

Over the past few decades, seaweed has been explored as a sustainable source in biotechnological and biomedical industries because of its multiple biopotential actions. However, the composition of biomolecules such as carbohydrates, lipids, fatty acids, free amino acids, ash, minerals, vitamins, and especially protein in green seaweeds varies from species to species based on their growth stage and the environmental conditions. Specifically, seaweed-derived bioactive proteins and peptides have the potential for several health benefits. They serve as a balanced diet. Protein which is an extensive macronutrient in human nutrition, should be explored to avoid using animal-sourced protein, which is expensive to consume. Bioactive peptides that are isolated from marine algae consist of various kinds of functional properties. In the food industry, seaweeds are novel molecules for being used in both nutritional foods and nutraceuticals. In both in vitro and In vivo conditions, various seaweed-derived bioactive compounds have shown a broad range of biological activities including anti-cancer and immunomodulatory, anti-hypertensive, and anti-coagulant activities. Hence, this review paper discusses the screening of seaweed-derived biochemicals with a special focus on their proteins, peptide contents, and nutra-pharmaceutical values.

Activities of antioxidant enzymes and Hsp levels in response to elevated temperature in land snail species with varied latitudinal distribution

Land snails occupy a variety of habitats, with differing temperature and humidity regimes and exhibit a wide span of adaptations, to withstand abiotic condition changes. The present work's aim was to examine the correlation of habitat's thermal adversity in different Mediterranean type habitats with the land snail's antioxidant and heat shock responses. For this purpose, snails of different species from populations along a north-south axis from the islands and mainland of Greece were exposed to elevated temperature and antioxidant enzyme activities, and Hsp70 and Hsp90 levels were determined in their tissues. The ATP, ADP, and AMP levels and the adenylate energy charge (AEC) were also determined. The comparison of protein levels and enzymatic activities across time intervals revealed significant differences for all factors examined. While the gradation pattern over time for a given factor was similar in all populations the absolute values over time differed. Catalase activity and the Hsp90 protein levels had the higher contribution in separating the different species and populations, followed by the activity of glutathione reductase and Hsp70 protein levels which contributed to a lesser degree. In general, populations from the southern part of their distribution in Greece tend to display a faster increase than northern populations in induction levels of all factors examined. Our data seem to be in line with the concept of preparation for oxidative stress (POS) while the changes in the AEC indicate an early preparation to cover the energy demand for the induction and synthesis of antioxidant enzymes and Hsps.

Seasonal cellular stress phenomena and phenotypic plasticity in land snail Helix lucorum populations from different altitudes

Temperature, a major abiotic environmental factor, regulates various physiological functions in land snails and therefore determines their biogeographical distribution. Thus, species with different distributions may present different thermal tolerance limits. Additionally, the intense reactivation of snail metabolic rate upon arousal from hibernation or estivation may provoke stress. Land snails, Helix lucorum, display a wide altitudinal distribution resulting in populations being exposed to different seasonal temperature variations. The aim of the present study was to investigate the expression of heat shock proteins (Hsps), mitogen activated protein kinases (MAPKs) and proteins that are related to apoptosis (Bcl-2, ubiquitin), that have 'cytoprotective' roles and are also considered to be reliable indicators of stress because of their crucial role in maintaining cellular homeostasis. These proteins were assessed in H. lucorum individuals from two different populations, one at Axios (sea level, 0 m) and the other at Kokkinopilos (Olympus, 1250 m), as well as after mutual population exchanges, in order to find out whether the different responses of these stress-related proteins depend solely on the environmental temperature. The results showed seasonally altered levels in all studied proteins in the hepatopancreas and foot of snails, both among different populations and between the same populations exposed to varying altitudes. However, individuals of the same population in their native habitat or acclimatized to a different habitat showed a relatively similar pattern of expression, supporting the induction of the specific proteins according to the life history of each species.

An Assessment of Snail-Farm Systems Based on Land Use and Farm Components

In this study, the structural and management characteristics of snail farms in Greece were analyzed to maximize sustainable food production. Objectives, such as the classification of farming systems and assessing the effects of various annual production parameters, were investigated. Data were collected (2017) via a questionnaire, and sampling was conducted in 29 snail farms dispersed in six different regions (Thrace, Central Macedonia, West Macedonia, Thessaly, Western Greece, and the Attica Islands). Descriptive statistics for continuous variables and frequencies for categorical variables were calculated. The similarity between farms was analyzed using nonmetric multidimensional scaling (nMDS). The average farm operation duration exceeded eight months and the mean annual production was 1597 kg of fresh, live snails. Results recorded five farming systems: elevated sections (7%), net-covered greenhouse (38%), a mixed system with a net-covered greenhouse (10%), open field (38%), and mixed system with an open field (7%). Snail farms differ in the type of substrate, available facilities, and equipment (60% similarity between most of the open field farms). The geographical location of a farms' settlement affects productivity but also influences the duration of operation, especially in open field farms, due to their operation under a wide assortment of climatic types.