Sturgeons in Greece: a review

In the past, sturgeons were practically unknown in Greece, both to the public and to scientists, the latter not having had the opportunity to study wild populations of the four native species. Populations of stellate sturgeon (Αcipenser stellatus Pallas, 1771), Adriatic sturgeon (Acipenser naccarii Bonaparte, 1836), and beluga sturgeon (Huso huso L., 1758) gradually collapsed by the end of the 1970s. Only the River Evros (Thrace, N.W. Greece) sustained a small fishery and caviar canning operation with European sturgeon (A. sturio L., 1758) until 1975. Collapse of stocks was mainly attributed to overfishing, pollution and damming. Sturgeons became widely known after initial farming efforts by the Municipal Hatchery at Lake Ioannina in 1992. Broodstock or fertilized eggs of species with high aquaculture potential, such as sterlet (Acipenser ruthenus L., 1758), Russian sturgeon (Acipenser gueldenstaedtii Brandt, 1833), bester hybrid (A. ruthenus ×H. huso), paddlefish (Polyodon spathula Walbaum, 1792), Siberian sturgeon (Acipenser baerii Brandt, 1869) and white sturgeon (Acipenser transmontanus Richardson, 1836) were imported into Greece between 1992 and 2004. Hatchery technology, larval rearing and production systems are reviewed in this paper and, despite problems, past and present efforts appear to meet a particular interest of the aquaculture sector as well as of those interested in the restoration of wild stocks.     

Molecular phylogenetic systematics of twelve species of Acipenseriformes based on mtDNA ND4L -ND4 gene sequence analysis

Acipenseriformes is an endangered primitive fish group, which occupies a special place in the history of ideas concerning fish evolution, even in vertebrate evolution. However, the classification and evolution of the fishes have been debated. The mitochondrial DNA (mtDNA) ND4L and partial ND4 genes were first sequenced in twelve species of the order Acipenseriformes, including endemic Chinese species. The following points were drawn from DNA sequences analysis: (i) the two species of Huso can be ascribed to Acipenser; (ii) A. dabryanus is the mostly closely related to A. sinensis, and most likely the landlocked form of A. sinensis; (iii) genus Acipenser in trans-Pacific region might have a common origin; (iv) mtDNA ND4L and ND4 genes are the ideal genetic markers for phylogenetic analysis of the order Acipenseriformes.     

Molecular phylogenetic systematics of twelve species of Acipenseriformes based on mtDNA ND4L -ND4 gene sequence analysis

Acipenseriformes is an endangered primitive fish group, which occupies a special place in the history of ideas concerning fish evolution, even in vertebrate evolution. However, the classification and evolution of the fishes have been debated. The mitochondrial DMA (mtDNA) ND4L and partial A7D4 genes were first sequenced in twelve species of the order Acipenseriformes, including endemic Chinese species. The following points were drawn from DNA sequences analysis: (i) the two species of Huso can be ascribed to Acipenser; (ii) A. dabryanus is the mostly closely related to A. sinensis, and most likely the landlocked form of A. sinensis; (iii) genus Acipenser in trans-Pacific region might have a common origin; (iv) mtDNA ND4L and ND4 genes are the ideal genetic markers for phylogenetic analysis of the order Acipenseriformes.     

Developmental basis for telencephalon expansion in waterfowl: enlargement prior to neurogenesis

Some altricial and some precocial species of birds have evolved enlarged telencephalons compared with other birds. Previous work has shown that finches and parakeets, two species that hatch in an immature (i.e. altricial) state, enlarged their telencephalon by delaying telencephalic neurogenesis. To determine whether species that hatch in a relatively mature (i.e. precocial) state also enlarged their telencephalon by delaying telencephalic neurogenesis, we examined brain development in geese, ducks, turkeys and chickens, which are all precocial. Whereas the telencephalon occupies less than 55 per cent of the brain in chickens and turkeys, it occupies more than 65 per cent in ducks and geese. To determine how these species differences in adult brain region proportions arise during development, we examined brain maturation (i.e. neurogenesis timing) and estimated telencephalon, tectum and medulla volumes from serial Nissl-stained sections in the four species. We found that incubation time predicts the timing of neurogenesis in all major brain regions and that the telencephalon is proportionally larger in ducks and geese before telencephalic neurogenesis begins. These findings demonstrate that the expansion of the telencephalon in ducks and geese is achieved by altering development prior to neurogenesis onset. Thus, precocial and altricial species evolved different developmental strategies to expand their telencephalon.     

Anthropogenic changes in the freshwater fish fauna of Italy, with reference to the central region and Barbus graellsii, a newly established alien species of Iberian origin

In a survey of the west-central Italian rivers Ombrone, Fiora, Albegna and Bruna, among established exotic species, the Iberian barbel Barbus graellsti was recorded in Italian fresh waters for the first time. Morphological identification was supported by comparison of cytochrome b sequences with those from related barbel species. Other exotics of particular note were Barbus barbus, Pseudorasbora parva and Leuciscus cephalus , together with the Padano-Venetian Chondrostoma genei and Padogobius bonelli. Native species still present included Leuciscus lucumonis, Telestes muticellus, Rutilus rubilio and Padogobius nigricans , but were now more restricted to upper reaches and smaller watercourses. The deleterious effect of alien species on native forms is discussed with particular reference to probable competition between C. genei and L. lucumonis , and between the two gobies. The checklist of species introduced to the fresh waters of Italy is now updated to 34. For the Italian freshwater fish fauna in general, the conservation status of three native species ( Acipenser naccari, Salmo marmoratus and Knipowitschia punctatissima ) has been improved but five species are believed to be at risk ( Salmo carpio, L. lucumonis, Scardinius scardafa, Gobio benacensis and P. nigricans ) and four anadromous species ( Petromyzon marinus, Lampetra fluviatilis, Acipenser sturio and Huso huso ) no longer breed in Italian fresh waters. The processes of change in the composition of the Italian freshwater fish fauna as a whole may be summarized as successively 'padanization', 'danubization' and now 'globalization'.     

长江口中华鲟自然保护区潮间带鱼类群落结构

为深入了解鱼类对潮间带水域的利用,2010年5月、8月、11月在长江口中华鲟自然保护区潮间带水域进行了插网调查。结果表明:调查期间共出现28种鱼类,隶属于10目16科,鲤形目种类最多,其次为鲈形目;群落优势种为中国花鲈(Lateolabrax maculates)、鮻(Liza haematocheila)和窄体舌鳎(Cynoglossus gracilis);长江口中华鲟自然保护区潮间带鱼类群落可以分为河口定居鱼类、海洋偶见鱼类、降海洄游鱼类、溯河洄游鱼类、海洋洄游鱼类和淡水鱼类6种生态类群,其中河口定居鱼类和海洋洄游鱼类占据明显优势。对调查水域鱼类群落进行聚类分析,结果表明秋季和春夏季差异显著,鮻、中国花鲈、斑尾刺虾虎鱼(Acanthogobius ommaturus)是对季节差异贡献最大的3种鱼类。主成分分析结果表明,夏季鱼类群落主要受到海洋洄游鱼类的影响,而秋季主要受到河口定居鱼类的影响,这2种鱼类的幼鱼在不同季节利用潮间带水域索饵肥育可能是造成季节差异的主要原因。     

Fatty acid makeup of various Brucella species and its relationship to the culture medium]

Gas chromatographic method was applied to the study of the fatty acid composition (in Br. melitensis, Br. abortus, Br. suis, and Br. ovis strains. Fatty acid composition was similar in the mentioned brucellae species, except Br. suis No. 1330 significantly differing by this sign. Methyleneoctadecanoic acid content was considerably elevated, and that of octadecenoic -- reduced in brucellae grown on liver agar with the addition of serum and on meat-peptone agar in comparison with brucellae grown on liver agar; apparently this represents one of the mechanisms of the microorganism adaptation to the less favourable conditions of the nutrient medium. Passage of Br. ovis strain through the guinea pig organism led to the appearance of brucellae forming two types of colonies when grown on liver agar with the addition of serum. The fatty acid composition of brucellae forming small transparent colonies was the same as that of the initial culture with the prevalence of methyleneoctadecanoic acid; as to brucellae with larger colonies with irregular margin and nontransparent centre of the colony--octadecenoic acid prevailed in their fatty acid composition, i.e. their composition was similar to such in brucellae of the melitensis and abortus species grown on liver agar.     

Somatosensory evoked potentials in the telencephalon of Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>) following galvanic stimulation of the tail

Electric activity in the brain which is time-locked to a given stimulation of the somatosensory system can be recorded as a somatosensory evoked potential (SEP). We investigated whether a galvanic stimulation of the tail base in Atlantic salmon (Salmo salar) would elicit a SEP in the telencephalon. The telencephalon is central in learning and memory, and activity here may be a prerequisite for processing of external stimuli on a cognitive or emotional level. Anaesthetized salmon (n = 11) were subjected to craniotomy and a recording electrode was inserted into the telencephalon. The fish were given stimulations of four intensities, i.e., 2, 5, 10 and 20 mA. A SEP was elicited in the contralateral dorsal telencephalon for all intensities. This result agrees with findings in other fish species. Furthermore, there was a significant difference between the maximum peak amplitude and mean amplitude of the SEP elicited by putative non-noxious (2 mA) and putative noxious (20 mA) stimulation intensities (P < 0.01). The stronger stimulation intensities also tend to introduce longer-latencies components in the SEP. The results added to the body of literature indicates that the exteroceptive senses are represented by processing within the telencephalon of the fish.     

Growth Respiration of a Flood-Tolerant and a Flood-Intolerant Senecio Species: Correlation between Calculated and Experimental Values

Root growth respiration of Senecio aquaticus Hill (flood-tolerant) and Senecio jacobaea L. (flood-sensitive) was calculated, assuming different P: O ratios. The growth respiration values were calculated on the basis of the chemical composition of root and shoot dry matter, in combination with published data on the energy costs of biosynthetic and transport processes. The comparison between calculated and experimental values suggests a relatively low efficiency of ATP utilization in the roots of the flood-tolerant species. Root growth respiration of S. congestus (R.Br.)DC., which is also flood-tolerant, and Plantago lanceolata L. were also determined. The data showed that not all the flood-tolerant species investigated had high root growth respiration values. An “overflow model’ is proposed to explain observed differences in root growth respiration between species.     

Millipede (Diplopoda) communities in an arboretum: Influence of tree species and soil properties

The paper deals with the influence of tree species on millipede communities (Diplopoda). The research was carried out in nine sites in the Borová hora arboretum (Zvolen town, Central Slovakia). Each studied site represents a monoculture of one of nine tree species: Betula pubescens Ehrh., Pinus sylvestris L., Larix decidua Mill., Carpinus betulus L., Abies alba Mill., Picea abies (L.) Karst., Alnus incana (L.) Moench, Populus nigra L., Ulmus laevis Pall. Millipedes were collected by pitfall trapping during vegetation periods in 2008-2011. In total, 1064 individuals of 17 species and 7 families were obtained. The results of research confirmed (i) an influence of tree species on the composition of millipede communities, (ii) a significant influence of soil nitrogen on the species richness and biodiversity, and (iii) an impact of soil pH on the species composition of these terrestrial invertebrate communities. In terms of total dynamic activity and species richness of millipedes, the most favourable conditions were revealed in the forest stands of Alnus incana, Populus nigra, Ulmus laevis and Carpinus betulus. On the contrary, the least favourable biotopes were (from both points of view) the forest stands of Betula pubescens and Larix decidua.     

Comparative coelomic fluid composition of sterlet sturgeon Acipenser ruthenus Linnaeus, 1758, Siberian sturgeon Acipenser baerii Brandt, 1869, and Russian sturgeon Acipenser gueldenstaedtii Brandt & Ratzeburg, 1833

The objectives of this study were to compare the physicochemical properties of coelomic fluid (CF) in three sturgeon species, sterlet sturgeon Acipenser ruthenus (age 5–8 years), Siberian sturgeon Acipenser baerii (age 15–20 years), and Russian sturgeon Acipenser gueldenstaedtii (age 13–18 years). For the study, CF was collected by plastic pipette from the eggs of mature female sterlet sturgeon (N = 10), Siberian sturgeon (N = 7) and Russian sturgeon (N = 4); osmolality, pH, ionic composition (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^?), glucose, cholesterol and total protein of the CF were then analyzed. Mean concentration of K⁺ (4.4–6.11 mmol/L), Cl^? (89.8–98.0 mmol/L), Ca²⁺ (0.87–0.96 mmol/L), Mg²⁺ (0.57–0.67 mmol/L), cholesterol (0.13–0.16 mmol/L), total protein (2.41–3.57 g/L), pH (7.92–7.98), and osmolality (190–213 mOsm/kg) of CF were not significantly different among these three species. However, the mean concentration of Na⁺ was significantly lower in sterlet sturgeon (104.6 ± 7.7 mmol/L; p < .05) than in the Siberian (126.4 ± 6.2) and Russian (123.0 ± 5.9) sturgeon. For these three species, Na⁺, K⁺, Cl^?, and Mg²⁺ were the dominating ions; several significant correlations were observed among these ions and other physiochemical properties of CF. This is the first report on the ionic and biochemical composition of the CF of sterlet, Siberian and Russian sturgeon, which can be used as a reference point for further development of artificial media for the short‐term storage of unfertilized sturgeon eggs as well as for the standardization of the fertilization protocol for these species in controlled reproduction.     

中草药食品抗氧化剂的筛选

为了寻找质优、价廉、丰富、易得的天然食品抗氧化剂资源,本文采用“扩散板法”和“永停法”从51种中草药中筛选出了二十三种活性较强的,其中大黄、牡丹皮、老鹳草、川续断、芡实,山茱萸核、马齿苋、八角回香、千里光和鹅不食草等10种抗氧活性最强(AI>70％)。     

Haematology of juvenile Acipenser oxyrinchus and Acipenser brevirostrum at rest and following forced activity

In vivo experiments were conducted to examine the haematology of juveniles from two relic bony fishes, Atlantic sturgeon Acipenser oxyrhinchus and shortnose sturgeon Acipenser brevirostrum . Oxygen transport characteristics (haematocrit, haemoglobin and mean erythrocytic haemoglobin concentration), ionic composition (Na⁺, Cl⁻, K⁺ and osmolality), metabolite concentration (lactate, cortisol and glucose) and protein content in blood were measured or calculated at rest and during recovery from forced activity. Under resting conditions, plasma osmolality and concentrations of Na⁺, Cl⁻, lactate, cortisol and total protein were significantly different between Atlantic and shortnose sturgeon. All other resting variables were not different between species. Following forced activity, plasma lactate levels were significantly higher in both species than at rest. Plasma cortisol levels in both species were only significantly higher 1 h following forced activity compared to resting values. Plasma lactate levels were significantly higher in Atlantic sturgeon than in shortnose sturgeon, but these levels returned to resting levels by 1 h in both species. Cortisol increases were greater in shortnose sturgeon than in Atlantic sturgeon. In general, oxygen transport characteristics, blood glucose, plasma protein and plasma osmolality were not altered by forced activity in either sturgeon species. Overall, both species had reduced responses ( i.e . the magnitude of changes in measured variables) to forced activity compared with teleosts.     

Phylogenetic relationships of the North American sturgeons (order Acipenseriformes) based on mitochondrial DNA sequences

The evolutionary relationships of the extant species within the order Acipenseriformes are not well understood. Nucleotide sequences of four mitochondrial genes (12S rRNA, COII, tRNA(Phe), and tRNA(Asp) genes) in North American sturgeon and paddlefish were examined to reconstruct a phylogeny. Analysis of the combined gene sequences suggests a basal placement of the paddlefish with regard to the sturgeons. Nucleotide sequences of all four genes for the three Scaphirhynchus species were identical. The position of Scaphirhynchus based on our data was uncertain. Within the genus Acipenser, the two Acipenser oxyrinchus subspecies were very similar in sequence and found to be basal to the remaining Acipenser species examined. Based on our data, Acipenser transmontanus and Acipenser medirostris were sister taxa, as were Acipenser fulvescens and Acipenser brevirostrum. Comparison of our results with hypotheses of sturgeon relationships proposed by previous authors is presented. The sequence data presented here are phylogenetically useful and provide a solid foundation of genetic information for the North American Acipenseriformes that can be expanded to include Eurasian species to provide a global picture of sturgeon evolution.     

香港蕨类植物分布新记录和名称修订(一)

记载香港地区蕨类植物9种,其中分布新记录2种,即粗齿紫萁和铁芒萁;名称修订5种,即粗叶卷柏、福建莲座蕨、华南紫萁、阔边假脉蕨和华南膜蕨;报道珍稀濒危蕨类2种,即广东小石松和粤紫萁．     

Comparison of the effects of gonadotropic preparations of the carp and stellate sturgeon pituitaries on in vivo and in vitro oocyte maturation in the Siberian sturgeon Acipenser baeri brandt

Injections of 2.5 mg/kg of stellate sturgeon (Acipenser stellatus Pall.) pituitary extract and 5 mg/kg of carp (Cyprinus carpio L.) pituitary extract in Siberian sturgeon (Acipenser baeri Brandt) females did not reveal significant differences in the effects of these preparations. There were no differences in the percentage of females that responded by ovulation, duration of the period from injection to ovulation, rate of ovulation, or quality of mature eggs as estimated by the percentage of fertilization or percentage of normal embryos at the small yolk plug stage. Thus, an insufficient efficiency in the artificial reproduction of the Siberian sturgeon grown in captivity is not related to the use of the carp pituitary preparation as a stimulus. Estimation of the ratio of specific activities of the pituitary extracts and purified gonadotropins of the stellate sturgeon and carp by in vitro oocyte maturation has shown that it varies within wide limits as a function of the medium composition and physiological state of follicles. Hence, the ratio of activities of the gonadotropins of different species as determined by in vitro maturation of sturgeon oocytes may markedly differ from that upon injection of these preparations in breeders.     

Comparative study of sturgeon oocyte soluble proteins by isoelectric focusing

1. Soluble caviar (oocyte) proteins of four sturgeon species from the Caspian sea, Acipenser stellatus (Sevrouga), Acipenser guldenstadti (Ossietre), Acipenser nudiventris (Chipe) and Huso huso (Belouga) were studied by isoelectric focusing. 2. Isoelectric focusing patterns of these proteins differ from one species to another and allow the identification of the specific origin of caviar. 3. Moreover, this technique allowed the discrimination of a subspecies, Acipenser guldenstadti persicus from the species. 4. This biochemical characterization of caviar proteins allowing identification of sturgeon species producing caviar could be added to data used in fraud tests.     

Particulate Matter on Foliage of 13 Woody Species: Deposition on Surfaces and Phytostabilisation in Waxes – a 3-Year Study

Particulate matter (PM) as an air pollutant can be harmful for human health through allergic, mutagenic and carcinogenic effects. Although the main focus is on decreasing air pollution, after PM has been emitted to the atmosphere, one of the realistic options to decrease it's concentrations in urbanized area will be phytoremediation. This study compared the capacity to capture PM from air of seven tree species commonly cultivated in Poland (Catalpa bignonioides Walter, Corylus colurna L., Fraxinus pennsylvanica Marsh., Ginkgo biloba L., Platanus × hispanica Mill. ex Muenchh., Quercus rubra L., Tilia tomentosa Moench ‘Brabant’) and six shrub species (Acer tataricum subsp. ginnala (Maxim.) Wesm., Sambucus nigra L., Sorbaria sorbifolia (L.) A.Br., Spiraea japonica L.f., Syringa meyeri C.K. Schneid. ‘Palibin’, Viburnum lantana L.). Significant differences were found between species in mass of total PM accumulation for two PM categories and three size fractions determined and in amount of waxes. A positive correlation was found between in-wax PM of diameter 2.5–10 μm and amount of waxes, but not between amount of waxes and amount of total PM or of any size fraction.     

Otoliths of sub-adult Lake Sturgeon Acipenser fulvescens contain aragonite and vaterite calcium carbonate polymorphs

In this study we quantified the percent CaCO₃ polymorph composition in otoliths of larval and juvenile Lake Sturgeon Acipenser fulvescens via X-ray microdiffraction. Sagittal otoliths of sub-adults were primarily composed of aragonite (> 90%) while the lapilli otoliths were 100% vaterite. This is the first time the presence of aragonite in otoliths has been reported in an acipenseriform and is surprising given that the ability to form aragonite otoliths was not thought to have evolved until the separation of teleost and holostean species from other Actinopterygian fishes (e.g., sturgeon, paddlefish, gar).