Reproduction of the Roman snail (Helix pomatia L.) from a local natural population in farm conditions and in a natural habitat

The aim of this study was to compare the quality of clutches and reproduction results of two groups of Roman snails (Helix pomatia) from the same local population, laying eggs simultaneously in semi-natural farm conditions and in a natural habitat. The study material were Roman snails aged 2 or more years which had entered the third phenological season of their life and thus the first season of sexual maturity. Observations were conducted at an earthen enclosure in a greenhouse belonging to the experimental farm for edible snails at the National Research Institute of Animal Reproduction in Balice near Kraków (Poland) as well as at a site where a local population naturally occurs in the uncultivated park surrounding the Radziwiłł Palace. In the June-July season, differences among such parameters as weight of clutch, number of eggs in clutch, mean egg weight, and hatchling percentage when compared to the total number of eggs in the clutch were compared. It was determined that clutches of eggs from the natural population laid in the greenhouse were of lesser weight (P<0.01), contained fewer eggs (P<0.05), and the mean weight of individual eggs was less (P<0.05) than in clutches laid simultaneously in a natural habitat. Both in the greenhouse and the natural habitat, in the first phase of laying eggs (June) the weight of the clutch and number of eggs its contained were greater than in the second phase (July). However, only for snails laying eggs in the greenhouse were these differences statistically significant (P<0.05) and highly significant (P<0.01), respectively. Statistically significant differences were not observed in hatchling percentage between eggs laid in the greenhouse and the natural habitat. The lower number of eggs laid in the farmed conditions of the greenhouse was successfully compensated for by the absence of mass destruction by rodents which occurred in the natural habitat.

Morphological characteristics of respiratory and digestive organs of Roman snail (Helix pomatia L., 1758)

The aim of this work was to study the structure of lung and hepatopancreas of Roman snail (Helix of pomatia of L., 1758). The study found that the lung occupies the lower turn of shell and presented by a saccate cavity, in the wall of that there are a kidney and heart with a pericardium, and also a rectum and ureter pass. An external surface of lungs covered by a shell and covered by an epidermis. An internal surface is covered by a flat ciliated epithelium and forms numerous folds in which pulmonary vessels and lacunae are accommodated. The branches of pulmonary vein have a thick muscular wall, that consists of circular and longitudinal muscular layers. An internal surface of lungs covered by the layer of mucus. Inhalation and exhalation are carried out due to reduction and relaxation of muscles of dorsal wall of the body that is named a “diaphragm”. Gas exchange occurs through the hemolymphatic capillaries of the lung wall. Respiratory motions take place not rhythmically, but through the different intervals of time depending on a requirement in oxygen. The frequency of pneumostome closing and opening is typically one time in a minute. At subzero humidity of atmospheric air of pneumostome closed by a mantle, and also one (or a few) epiphragms. The hepatopancreas (“liver” or liver gland) is in the upper rotation of the sink and formed by two parts: right and left, from which two liver ducts enter into the stomach respectively. The liver gland consists of many acinuss, surrounded by connecting tissue, that contains small number of muscular fibres. Calcium cells have a pyramidal form and usually do not reach the lumen of the acinus. Cytoplasm of calcium cells contains inclusions: grains of phosphoricacid lime and drops of fat. The digestive cells of the hepatopencreas are more elongated, often clavicular. Сytoplasm of digestive cells is loose and vacuolated and contain inclusions of yellow-green color. Enzyme cells on histopreparations are difficult to distinguish from digestive ones. They contain transparent vacuoles with a large round inclusion of yellow-green color, which consists of a cluster of several grains of different sizes. Hepatopancreas performs the following functions: secretory (enzyme cells), absorption and intracellular digestion (digestive cells), preservation of nutrients and calcium (calcium cells), and also excretory function.

Neonicotinoids: Spreading, Translocation and Aquatic Toxicity

Various environmental and ecotoxicological aspects related to applications of neonicotinoid insecticides are assessed. Dosages of neonicotinoids applied in seed coating materials were determined and are compared to other applications (spray and granule). Environmental levels in soils and affecting factors in translocation are discussed. Excretion of neonicotinoids via guttation from coated maize seeds up to two months upon emergence, as well as cross-contamination of plants emerged from non-coated seeds or weeds nearby have been demonstrated. Contamination of surface waters is discussed in scope of a worldwide review and the environmental fate of the neonicotinoid active ingredients and the formulating surfactant appeared to be mutually affected by each other. Toxicity of neonicotinoid active ingredients and formulations on Daphnia magna completed with some investigations of activity of the detoxifying glutathione S-transferase enzyme demonstrated the modified toxicity due to the formulating agents. Electrophysiological results on identified central neurons of the terrestrial snail Helix pomatia showed acetylcholine antagonist (inhibitory) effects of neonicotinoid insecticide products, but no agonist (ACh-like) effects were recorded. These data also suggested different molecular targets (nicotinergic acetylcholine receptors and acetylcholine esterase enzyme) of neonicotinoids in the snail central nervous system.

Roman Snail, Helix pomatia (Mollusca: Helicidae), in Canada

Populations of Roman Snail, Helix pomatia, a large European land snail, are reported for the first time in Canada from disturbed habitats in two distant locations: Sarnia, Ontario and Montrose, British Columbia. As Roman Snail is an edible species subject to international commercial trade, its deliberate, but illegal, introduction into Canada and intentional or unintentional releases are possible sources of these populations.

The Use of Exoglycosidases for the Assay of Two New Enzymatic Substrates, b-D-xylopyranosyl-4-nitrocatechol-1-yl and a-lactosyl-4-nitrocatechol-1-yl

Glycosylation acceptor, 4-nitrocatechol, has been prepared via 4-nitrocatechol sulfate (2-hydroxy-5-nitrophenyl sulfate). The two carbohydrates, D-xylose and lactose, were peracetylated and then served as glycosylation donors in a modified Helferich glycosylation method, by using BF3� OBu2 as a promotor. The new synthesized glycosides were crystallized from ethanol and then submitted to Z�mplen saponification and separated by preparative thin layer chromatography (TLC). We have isolated two xylosides. Reaction mixture of lactoside proved to be unitary, a single product could be isolated. Small portions of the synthetic glycosides were re-acetylated and their 1H and 13C NMR spectra registered. The two separated xylosides were b- and a-xylopyranoside-4-nitrocatechol-1-yl. Being submitted to the action of an enzymatic extract from digestive tract of snail (Helix pomatia) only the b-anomer was susceptible to enzymatic hydrolysis. The isolated lactoside proved to be the a-isomer. Under the action of an enzymatic extract from wheat (Triticum aestivum) germs, it was sequencially cleaved, as indicated by a kinetic TLC analysis.