Detection of hybridization between two loach species (<Emphasis Type="Italic">Paramisgurnus dabryanus</Emphasis> and <Emphasis Type="Italic">Misgurnus anguillicaudatus</Emphasis>) in wild populations

Artificial interspecific hybrids between large scale loach P. dabryanus and tetraploid pond loach M. anguillicaudatus (Cobitidae, Cypriniformes) are viable. To detect the occurrence of possible natural hybridization, genetic analyses by using microsatellite markers were performed for natural populations of large scale loach and pond loach, the reciprocal laboratory hybrids, and “supposed hybrids” with ambiguous morphology. The fertility of the artificial hybrids was also tested. At one diagnostic microsatellite (Mac50), one out of 20 “supposed hybrids” was identified to be F₁ hybrid between the two loach species because it had the same genotype as that of the laboratory hybrids. The triploid hybrids between the two species were confirmed to be female-sterile. The results show that rare hybridization has occurred between diploid large scale loach and tetraploid pond loach in nature although it may have little effect in genetic introgression. This study is helpful for fish conservation and encourages further investigation on natural hybridization and introgression of loaches.     

Genetic and environmental variations in quantitative characters in fishes: a comparative analysis of monoclonal triploid and bisexual tetraploid spined loaches (<Emphasis Type="Italic">Cobitis</Emphasis>, Cobitidae)

The heritability estimates of 25 external morphometric characters and 23 craniometric indices are obtained by use of variances in monoclonal all-female triploids and bisexual tetraploids of spined loaches (genus Cobitis, Cobitidae) collected from the same breeding biotope. Most of studied traits demonstrate low heritability confirming previous conclusion on the similarity between external morphometric characters and craniological indices in relative effects of genetic and environmental components in their total phenotypic variation. Low heritability estimates in most of external morphological traits correspond to their low diagnostic value in Cobitis species. As a whole, in spite of certain deviations, studies on clonal forms do not refute the concept on higher heritability estimates in diagnostically significant traits in comparison with traits without diagnostic values in the same taxonomic group. Low heritability in most morphometric traits more probably is resulted from their low additive genetic variation caused by strong selection of evolutionary developed specific body shape in spined loaches, because strong selection should reduce the genetic variance in body proportions to minimal size. Sex differences observed in heritability estimates should be interpreted as a result of linkage of several additive genes controlling these traits to sex chromosomes. A few characters demonstrating high heritability estimates up to 0.492–0.580 are of great interest for taxonomic and phylogenetic studies in genus Cobitis and related taxa.     

Spawning habitat in the spined loach, <Emphasis Type="Italic">Cobitis taenia</Emphasis> (Cypriniformes: Cobitidae)

Spawning habitat of the endangered spined loach Cobitis taenia was studied in northwestern Germany. The distribution of eggs of the loach in the field was best correlated with the density of vegetation but had little correlation with current velocity, water depth, or bottom substrate. In the aquarium, the loach chose dense vegetation for an oviposition site, as inferred by the direct observations of spawning and the location of spawned eggs. It is concluded that such habitat specialization is an important element in the autecology of the endangered fish and a critical stage in the habitat requirements of its populations.     

Spatial and ontogenetic variability in the microhabitat use of stream-dwelling spined loach (Cobitis taenia) and stone loach (Barbatula barbatula)

Ontogenetic and spatial variability in microhabitat use of spined loach Cobitis taenia (Linnaeus), considered as one species for the purposes of this study, and stone loach Barbatula barbatula (Linnaeus) were examined in the River Great Ouse basin, England, using multivariate and habitat suitability methods, including a technique for handling spatial variation in collections of preference curves. Distinct ordinations of spined age classes and stone loach developmental stages, respectively, in canonical correspondence analysis of species × variables × samples relationships suggest that the two species occupy completely different microhabitats; however, young‐of‐the‐year spined loach occurred more often than expected with all developmental stages of stone loach except young larvae. Water velocity and filamentous algae were the most influential microhabitat variables, the latter decreasing in importance with increasing age of both fish species. Preferred water velocities generally decreased with age in spined loach and increased in stone loach, with substratum size generally increasing with fish age in both species. Spatial variation in microhabitat preferences was great in both species but less so in the spined loach, suggesting that limited plasticity in habitat use could account, at least in part, for the latter species’ limited distribution and abundance in the catchment. Preference curves for a species, if generated and verified for all life intervals and all seasons, could be used as a management tool for a given stream or sector of river basin. But preference curves should be generated for each location to ensure that river management decisions with regard habitat and species conservation consider local‐level species requirements. Thus, a multi‐(eco)species and multi‐scale approach is required in habitat suitability assessments.     

Genetic variation among populations of the endangered fan mussel <Emphasis Type="Italic">Pinna nobilis</Emphasis> (Mollusca: Bivalvia) along the Tunisian coastline

The Mediterranean fan mussel Pinna nobilis is an endangered invertebrate due to overexploitation and habitat deterioration. In this species, two distinctive morphs, the “combed” and “straight and wide” forms, have been recorded and it is not known whether this morphometric variability is attributed to genetic or environmental factors. In this study, we used mitochondrial COI sequences to describe the genetic variability of five Pinna nobilis populations sampled along the northern, eastern, and southern Tunisian coastline, and to examine whether there is a genetic differentiation between the two forms of this species. DNA sequences of 675 bp from the mitochondrial COI gene have revealed 10 different haplotypes among 49 examined specimens. Haplotype diversity was high, ranging between 0.40441 and 0.80952, and showed a decreasing North-East gradient, which seems to be explained by the hydrogeography of the study area. The mitochondrial COI marker did not suggest a genetic distinctiveness between the two Pinna nobilis shell forms, “combed” and “straight and wide”. Although the morphometric plasticity of the fan mussel could be due to the influence of environmental factors, further genetic studies using nuclear markers are envisaged to investigate whether this differentiation is associated to gene flow restrictions.     

Sex differences in optimal incubation temperatures in a scincid lizard species

Most theoretical models for the evolution of temperature-dependent sex determination (TSD) rely upon differential fitness of male and female offspring incubated under different thermal regimes. However, there are few convincing data on this topic. We studied incubation effects in a lizard species (Bassiana duperreyi, Scincidae) with genotypic sex determination, so that we could separate effects due to incubation temperatures from those due to offspring gender. We incubated eggs under two different fluctuating-temperature regimes that simulated hot and cold natural nest-sites. The effects of our incubation treatments on phenotypes of the hatchling lizards (morphology and locomotor performance) differed between the sexes. Females emerging from eggs exposed to the “hot nest” treatment (diel cycling, 23–31°C) were larger, and ran faster, than did their sisters from the “cold nest” treatment (16–24°C). Males showed a smaller and less consistent phenotypic response than females. These incubation-induced responses were relatively stable during the first few weeks of life post-hatching, at least in captive lizards maintained under laboratory conditions. These kinds of sex differences in the phenotypic responses of hatchling reptiles to incubation conditions provide a plausible basis for the evolution of temperature-dependent sex determination in reptiles. Received: 07 May 1998 / Accepted: 16 November 1998     

Simultaneous formation of haploid, diploid and triploid eggs in diploid–triploid mosaic loaches

In the loach Misgurnus anguillicaudatus , very few diploid–triploid mosaic individuals, which are generated by accidental incorporation of the sperm nucleus into diploid eggs produced by clonal diploid loach, occur in nature. Ploidy examination of gynogenetic progeny induced by activation with ultraviolet-irradiated goldfish sperm indicated that diploid–triploid mosaic females laid haploid, diploid and triploid eggs, simultaneously. In addition, triploid eggs exhibited larger egg sizes. Microsatellite genotyping of diploid–triploid mosaics revealed that triploid genotypes of mosaic mothers possessed two alleles specific to the clonal diploid and one allele from normal diploid male. Diploid eggs from a mosaic mother had genotypes absolutely identical to the diploid clone. Most genotypes of triploid eggs were identical to the mosaic mother, and one of the three alleles of the mosaic mother was transmitted to haploid eggs. These results suggested that diploid germ cells, which had a clonal genome, were differentiated into clonal diploid eggs, and triploid and haploid eggs were produced from triploid germ cells in the same ovary of mosaic individuals.     

Polymorphism of canonical and noncanonical <Emphasis Type="Italic">gypsy</Emphasis> sequences in different species of <Emphasis Type="Italic">Drosophila </Emphasis><Emphasis Type="Italic">melanogaster</Emphasis> subgroup: possible evolutionary relations

Mobile genetic elements constitute a substantial part of eukaryotic genome and play an important role in its organization and functioning. Co-evolution of retrotransposons and their hosts resulted in the establishment of control systems employing mechanisms of RNA interference that seem to be impossible to evade. However, “active” copies of endogenous retrovirus gypsy escape cellular control in some cases, while its evolutionary elder “inactive” variants do not. To clarify the evolutionary relationship between “active” and “inactive” gypsy we combined two approaches: the analysis of gypsy sequences, isolated from G32 Drosophila melanogaster strain and from different Drosophila species of the melanogaster subgroup, as well as the study of databases, available on the Internet. No signs of “intermediate” (between “active” and “inactive”) gypsy form were found in GenBank, and four full-size G32 gypsy copies demonstrated a convergence that presumably involves gene conversion. No “active” gypsy were revealed among PCR generated gypsy ORF3 sequences from the various Drosophila species indicating that “active” gypsy appeared in some population of D. melanogaster and then started to spread out. Analysis of sequences flanking gypsy variants in G32 revealed their predominantly heterochromatic location. Discrepancy between the structure of actual gypsy sites in G32 and corresponding sequences in database might indicate significant inter-strain heterochromatin diversity. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Reproduction of spined loach, Cobitis taenia, (Cypriniformes; Cobitidae) under laboratory conditions

A simple and reliable method is described for breeding spined loach, Cobitis taenia Linnaeus, 1758, under laboratory conditions. Three 40 L aquaria were each provided with a thick tuft of moss placed on top of a gauze-covered plastic box to serve as a spawning site. Ovoposition always occurred in the most densely available vegetation. The nonadhesive eggs fell through the gauze into the box. The spined loach is a fractional spawner releasing eggs in 14–18 batches at intervals of 2–23 (median 6) days. The total number of eggs per female was 2905–4282 during the reproductive season of 101–120 days. Yolks measured 1.14 ± 0.07 mm and eggs were 2.54 ± 0.22 mm in diameter. Total larval length was 5.03 ± 0.34 mm at hatching and 6.77 ± 0.34 mm at the beginning of exogenous feeding. The method allowed the rearing of numerous young for conservation measures and experimental investigations.     

Echiniscus corrugicaudatus (Heterotardigrada; Echiniscidae) a new species from Ellsworth Land, Antarctica

Echiniscus corrugicaudatus sp. nov., (Heterotardigrada; Echiniscidae) was found in the limited vegetation from the inland nunataks of Ellsworth Land, West Antarctica. The tardigrade fauna of this a rarely explored region shows limited overlap with the fauna from the maritime or coastal continental Antarctic. This species is placed within the Echiniscus “arctomys-group” based on the characteristic of, “a lack of body appendages other than cirrus A”. It has less well-defined edges to the dorsal plates than other species within the group and distinct ridges on the caudal plate. Males were found in the population indicating gonochoristic reproduction, and a large number of juveniles suggesting an over-wintering strategy of eggs or a biennial population over-wintering as adults/sub-adults and eggs.     

Phenotypic plasticity in the Antarctic fish <Emphasis Type="Italic">Trematomus newnesi</Emphasis> (Nototheniidae) from the South Shetland Islands

The presence of the two morphs, “typical” and “large mouth”, in the Antarctic fish species Trematomus newnesi (Perciformes, Notothenioidei) was recorded for the first time in nearshore waters of the South Shetland Islands (Potter Cove) and western Antarctic Peninsula (Petermann Island). The two morphs were distinguishable in specimens of 60–241 mm total length (TL); about 30% of the specimens constituted intermediate forms. In addition to the previously known characters separating the morphs, we found that the “relative size of the eye” can also be used to identify smaller and larger fish of the typical morph. The ecological significance of the two morphs remains unclear. Ratios of diagnostic characters for identification of the species at two size ranges (60–131 and 132–241 mm TL) are provided.     

Incipient morphological castes in <Emphasis Type="Italic">Polistes gallicus</Emphasis> (Vespidae,Hymenoptera)

The occurrence of a pre-imaginal caste determination represents a sort of “point of no return” to eusociality. In some social insect taxa, including Polistes species, the occurrence of distinct queen and worker castes is still debated. Before this report, no clear morphological differences between reproductive and non-reproductive individuals were known. Here we show that several pre-imaginal morphological differences of the Van der Vecht organ occur between foundresses (queens) and workers. Geometric morphometrics revealed that queens are characterized by shape deformations of this organ, which is responsible for a typical allometric growth of the secretory area. This organ is predicted to be larger in foundresses compared to workers because its secretion is involved in defense against ants, in nestmate recognition and in preventing workers from challenging for direct reproduction. The results presented here indicate the existence of an incipient morphological caste determination Polistes gallicus and suggest that this species may have passed the “point of no return” for eusociality.     

Study on high-temperature-resistant and high-yield <Emphasis Type="Italic">Laminaria</Emphasis> variety “Rongfu”

Hybridization of gametophytes, continuous self-crossing and targeted selection were utilized to breed a new Laminaria variety. After five-generation selection breeding, the new variety “Rongfu” was obtained. Its male parent “Yuanza No.10” was the high-yield cultivation variety, and its female parent was variety “Fujian” which could tolerate relatively high seawater temperature. “Yuanza No.10” and “Fujian” were different but complement in their morphological characteristics and biological habits. Variety “Rongfu” was bred through their hybridization which exhibited high-yield potential and high seawater temperature tolerance. The results of traits evaluation in consecutive years showed that “Rongfu” attained higher yields by 24–27% compared to the control (widely used commercial variety) and also contained considerable amounts of iodine, mannitol, and algin. When seawater temperature was 18–21°C, the blade growth of “Rongfu” was maintained and tissue loss by abrasion was significantly lower than the control. Since the adoption of variety “Rongfu” in 2001, its cultivation areas have been extended to Shandong, Fujian and Guangdong province and have reached 14,133 ha currently, i.e., almost one-tenth of the total cultivation areas of Laminaria in China. The results of Random Amplified Polymorphic DNA analysis showed that the relationship between “Rongfu” and other cultivation varieties in China was very close.     

Clonal diversity of <Emphasis Type="Italic">Clintonia udensis</Emphasis> Trautv. <Emphasis Type="Italic">et</Emphasis> Mey. populations and its correlation with ecological factors

The clonal diversity of Clintonia udensis Trautv. et Mey. was detected by ISSR markers among 16 populations, and its correlation with ecological factors was analyzed as well in this work. Results showed that individuals (clonal ramets) per genotype were 1.12 and 1.149 at population and species levels, respectively, and that the 16 populations were all multiclonal. The detected genotypes were localized, without exception, within populations but demonstrated relatively high clonal differentiation among populations. The clonal diversity of the studied populations was high, with the average Simpson’s index of 0.975, while the genets showed a clonal architecture of “guerilla”. The population genetic diversities revealed by genet were consistent with those by ramet, further confirming their genetic differentiation among populations. And its genotype diversity within populations probably resulted largely from the frequent seedling regeneration and self-compatibility. In addition, the correlation analysis further revealed that, among the ecological factors, Simpson’s index of C. udensis had a significant positive correlation (P<0.05) with pH values in the soil but not others.     

Genetic structure of a diploid-polyploid complex of the spined loach Cobitis taenia (Cypriniformes: Cobitidae) from the middle Dnieper bassin

Biochemical genetic typing and cytometry showed that polyploid females account for 87% of the spined loach Cobitis taenia population from the middle Dnieper basin. The polyploidy series included triploids, tetraploids, and, possibly, a few pentaploids. A characteristic feature of the genetic structure of polyploids was that their genetic variation was due to the clonal variation in the haploid portion of the genome originating from Cobitis sp. and to polymorphism of the diploid portion originating from C. taenia. The results are discussed with regard to comparative evolution of alloploid complexes in fish and terrestrial vertebrates.     

Chemistry, antiproliferative properties, tumor selectivity, and molecular mechanisms of novel gold(III) compounds for cancer treatment: a systematic study

Abstract  

The antiproliferative properties of a group of 13 structurally diverse gold(III) compounds, including six mononuclear gold(III) complexes, five dinuclear oxo-bridged gold(III) complexes, and two organogold(III) compounds, toward several human tumor cell lines were evaluated in vitro using a systematic screening strategy. Initially all compounds were tested against a panel of 12 human tumor cell lines, and the best performers were tested against a larger 36-cell-line panel. Very pronounced antiproliferative properties were highlighted in most cases, with cytotoxic potencies commonly falling in the low micromolar—and even nanomolar—range. Overall, good-to-excellent tumor selectivity was established for at least seven compounds, making them particularly attractive for further pharmacological evaluation. Compare analysis suggested that the observed antiproliferative effects are caused by a variety of molecular mechanisms, in most cases “DNA-independent,” and completely different from those of platinum drugs. Remarkably, some new biomolecular systems such as histone deacetylase, protein kinase C/staurosporine, mammalian target of rapamycin/rapamycin, and cyclin-dependent kinases were proposed for the first time as likely biochemical targets for the gold(III) species investigated. The results conclusively qualify gold(III) compounds as a promising class of cytotoxic agents, of outstanding interest for cancer treatment, while providing initial insight into their modes of action.     

PIT-tagging Italian spined loach (Cobitis bilineata): Methodology,survival and behavioural effects

The Italian spined loach (Cobitis bilineata) is an elongated, small-sized (<12 cm) spined loach native to northern Italy, Slovenia and Croatia. As for loaches in general, little is known about the individual movements of this loach in nature. Passive integrated transponders (PIT-tags) are small (typically 7–32 mm), relatively cheap and allow tracking of individual fish movements and behaviour. A fundamental assumption in animal telemetry is that the performance of a tagged animal does not deviate substantially from its natural performance. Although PIT-tagged fish often display high survival and tag retention, the effect varies between species and contexts, and few studies have looked at behavioural effects of PIT-tagging. Here we demonstrate a PIT-tagging methodology for spined loaches, and compare survival, activity and provoked escape response (maximum swimming speed) between tagged and control fish. We also track tag retention in the tagged fish. Italian spined loaches tagged with 12 mm PIT-tags displayed high tag retention and no extra mortality, and no effects of tagging on activity or maximum swimming speed were observed. The tag-to-fish weight and length ratios in our study ranged from 2% to 5% and from 10% to 16%, respectively, and we conclude that PIT-tagging, within these ratios, appears suitable for Italian spined loach.     

Variation of coloration in <Emphasis Type="Italic">Lycodes yamatoi</Emphasis> Toyoshima, 1985 (Pisces: Zoarcidae) in the northern Sea of Japan

Specimens of eelpouts were found in the northern Sea of Japan that were externally similar to Lycodes yamatoi Toyoshima, 1985, but their coloration differed from the coloring known for this species. Comparative analysis of meristic characters and sequence comparison of mtDNA COI and cytb gene fragments did not reveal distinctions between specimens with different types of coloration. All studied specimens belong to L. yamatoi. The live color pattern of L. yamatoi is characterized by high variation, with two main types of coloration, “dark” and “bright.”     

Traditional Knowledge and Management of <Emphasis Type="Italic">Feijoa (Acca sellowiana)</Emphasis> in Southern Brazil

Traditional Knowledge and Management of Feijoa (Acca sellowiana) in Southern Brazil. This paper investigates traditional knowledge of the use and management of Acca sellowiana in southern Brazil. Fifty-six informants from three rural communities were assigned to one of four subgroups (“maintainers,” “managers,” “cultivators,” or “users”) based on their responses regarding management and use of A. sellowiana. Traditional knowledge related to use of this species is widespread among rural residents, but traditional knowledge related to management is fragmented depending on whether one uses, manages, or cultivates the species. Knowledge held in rural communities suggests that A. sellowiana could play an expanded role in local economies as well as biodiversity conservation. We suggest that participatory research could stimulate greater local use as well as on-farm conservation of A. sellowiana.