Mineralized cartilage in the skeleton of chondrichthyan fishes

The cartilaginous endoskeleton of chondrichthyan fishes (sharks, rays, and chimaeras) exhibits complex arrangements and morphologies of calcified tissues that vary with age, species, feeding behavior, and location in the body. Understanding of the development, evolutionary history and function of these tissue types has been hampered by the lack of a unifying terminology. In order to facilitate reciprocal illumination between disparate fields with convergent interests, we present levels of organization in which crystal orientation/size delimits three calcification types (areolar, globular, and prismatic) that interact in two distinct skeletal types, vertebral and tessellated cartilage. The tessellated skeleton is composed of small blocks (tesserae) of calcified cartilage (both prismatic and globular) overlying a core of unmineralized cartilage, while vertebral cartilage usually contains all three types of calcification.     

Fauna and zoogeography of deep-benthic chondrichthyan fishes around the Japanese Archipelago

The deep-benthic chondrichthyan fishes collected by 584 hauls of otter-trawl from the Okinawa Trough, Kyushu-Palau Ridge, Pacific continental slope off northern Honshu Island (“Tohoku Slope”) and continental slope of Okhotsk Sea off Hokkaido (“Okhotsk Slope”) were analyzed. Sixty-one species were recorded from 200 to 1,520 m in depths; 37 species from the Okinawa Trough, 10 from the Kyushu-Palau Ridge, 18 from the Tohoku Slope, and nine from the Okhotsk Slope. The Okinawa Trough has the most varied composition, with many species of the Squalidae, Scyliorhinidae, and Rajidae (genusRaja). The Kyushu-Palau Ridge has a relatively high number of squalid species, but no species of the Rajidae or Chimaeriformes. The Tohoku Slope fauna is relatively varied, comprising six families, of which the Rajidae (genusBathyraja) is the most numerous, followed by the Squalidae. The Okhotsk Slope has the least number of species, and is characterized by a remarkable dominance of the Rajidae (genusBathyraja).     

A modern system of Fusarium taxonomy

A modern system of Fusarium taxonomy is proposed, based on the study over 30 years, of the morphology and growth characteristics of fungi of this genus, and their variability under a wide range of conditions. The system proposed here comprises 13 sections, 33 species and 14 varieties. It differs from systems published by other authors mainly in the sections Eupionnotes, Sporotrichiella, Arthrosporiella, Gibbosum, Discolor, Macroconia and Martiella.     

Immunization of fishes: a review

Immune response in fishes, which are ectothermic animals, depends on temperature. The optimum response is at the optimum temperature for the species. It is, however, slower in coldwater fishes, such as salmonids, and faster in warmwater fishes. Serum of fishes contains proteins very similar, but not identical, with those of mammals. Immune bodies are contained in gamma, beta, and alpha globulins. Gamma globulin is absent in some fishes. Fishes can be effectively immunized by injection of antigens, however, this is not a practical method. For this reason oral immunization has been attempted repeatedly but the effectiveness is variable.     

Bacterial flora of fishes: A review

Bacterial floras isolated from eggs, skin, gills, and intestines have been described for a limited number of fish species. Generally, the range of bacterial genera isolated is related to the aquatic habitat of the fish and varies with factors such as the salinity of the habitat and the bacterial load in the water. In many investigations, identification of isolates to the genus level only makes it difficult to determine the precise relationships of aquatic and fish microfloras. Bacteria recovered from the skin and gills may be transient rather than resident on the fish surfaces. Microfloras of fish intestines appear to vary with the complexity of the fish digestive system. The genera present in the gut generally seem to be those from the environment or diet which can survive and multiply in the intestinal tract, although there is evidence for a distinct intestinal microflora in some species. While obligate anaerobes have been recovered from carp and tilapia intestines, low ambient temperatures may prevent colonization by anaerobes in species such as rainbow trout.     

Transgenic fishes: modern state of the problem

Transgenic fishes are the object for the specialists in different research fields. It seems very promising to cultivate the rapidly growing objects resistant to diseases and negative environmental factors as well as the indicators of pollutions, models for oncological investigations etc. Some methodical, piscicultural, medical, ecological and others aspects of investigations of transgenic fishes as well as the legislative basis of Ukraine on this problem are discussed in the article.     

Protist taxonomy: an ecological perspective

This is an exploration of contemporary protist taxonomy within an ecological perspective. As it currently stands, the 'morphospecies' does not accommodate the information that might support a truly ecological species concept for the protists. But the 'morphospecies' is merely a first step in erecting a taxonomy of the protists, and it is expected to become more meaningful in the light of genetic, physiological and ecological research in the near future. One possible way forward lies in the recognition that sexual and asexual protists may all be subject to forces of cohesion that result in (DNA) sequence-similarity clusters. A starting point would then be the detection of 'ecotypes'--where genotypic and phenotypic clusters correspond; but for that we need better information regarding the extent of clonality in protists, and better characterization of ecological niches and their boundaries. There is some progress with respect to the latter. Using the example of a community of ciliated protozoa living in the stratified water column of a freshwater pond, it is shown to be possible to gauge the potential of protists to partition their local environment into ecological niches. Around 40 morphospecies can coexist in the superimposed water layers, which presumably represent different ecological niches, but we have yet to discover if these are discrete or continuously variable. It is a myth that taxonomic problems are more severe for protists than for animals and plants. Most of the fundamental problems associated with species concepts (e.g. asexuals, sibling species, phenotypic variation) are distributed across biota in general. The recent history of the status of Pfiesteria provides a model example of an integrated approach to solving what are essentially taxonomic problems.     

Spatial scales in the study of reef fishes: A theoretical perspective

Abstract Theoretical models imply that spatial scale derives its greatest importance through interactions between density-dependent processes and spatial variation in population densities and environmental variables. Such interactions cause population dynamics on large spatial scales to differ in important ways from predictions based on measurements of population dynamics at smaller scales, a phenomenon called the scale transition. These differences can account for large-scale population stability and species coexistence. The interactions between density dependence and spatial variation that lead to the scale transition can be understood by the process of non-linear averaging, which shows how variance originating on various spatial scales contributes to large-scale population dynamics. Variance originating below the scale of density dependence contributes less to the scale transition as the spatial scale of the variation declines, while variation originating on or above the scale of density dependence contributes independently of the spatial scale of the variation.     

A phylogenetic perspective on the evolution of Mediterranean teleost fishes

The Mediterranean Sea is a highly diverse, highly studied, and highly impacted biogeographic region, yet no phylogenetic reconstruction of fish diversity in this area has been published to date. Here, we infer the timing and geographic origins of Mediterranean teleost species diversity using nucleotide sequences collected from GenBank. We assembled a DNA supermatrix composed of four mitochondrial genes (12S ribosomal DNA, 16S ribosomal DNA, cytochrome c oxidase subunit I and cytochrome b) and two nuclear genes (rhodopsin and recombination activating gene I), including 62% of Mediterranean teleost species plus 9 outgroups. Maximum likelihood and Bayesian phylogenetic and dating analyses were calibrated using 20 fossil constraints. An additional 124 species were grafted onto the chronogram according to their taxonomic affinity, checking for the effects of taxonomic coverage in subsequent diversification analyses. We then interpreted the time-line of teleost diversification in light of Mediterranean historical biogeography, distinguishing non-endemic natives, endemics and exotic species. Results show that the major Mediterranean orders are of Cretaceous origin, specifically ~100-80 Mya, and most Perciformes families originated 80-50 Mya. Two important clade origin events were detected. The first at 100-80 Mya, affected native and exotic species, and reflects a global diversification period at a time when the Mediterranean Sea did not yet exist. The second occurred during the last 50 Mya, and is noticeable among endemic and native species, but not among exotic species. This period corresponds to isolation of the Mediterranean from Indo-Pacific waters before the Messinian salinity crisis. The Mediterranean fish fauna illustrates well the assembly of regional faunas through origination and immigration, where dispersal and isolation have shaped the emergence of a biodiversity hotspot.     

川蔓藻属系统分类和演化评述

川蔓藻属Ruppia为沉水单子叶植物,世界广布,主要为咸水和盐水生境,具有重要的生态价值、环境指示作用以及植物系统学研究意义.长期以来,川蔓藻属内种的数目以及属的系统位置一直存在争议.根据已有研究资料,目前川蔓藻属共有5个种--R.maritima、R cirrhosa、R. tuberosa、R, megacarpa和R.tuberosa、R.megacarpa和R.palycarpa得到多数学者的认可.关于其系统位置,主要有隶属于眼子菜科Potamogetonaceae和独立成川蔓藻科Ruppiaceae两种观点.尽管目前许多被子植物分类系统都承认了川蔓藻科.近年来分子系统学研究显示川蔓藻属与丝粉藻科cymodoceaceae和波喜荡科Posidoniaceae有近的亲缘关系,但对川蔓藻属和眼子菜属Potamogeton区别特征的比较结果倾向于支持将其放在眼子菜科.本文还结合川蔓藻属及相关类群的化石记录和果实特征对其演化进行了初步探讨,化石属Limnocarpus和Midravalva被认为是川蔓藻属较早的祖先类群,并认为该属植物应该是由淡水祖先逐渐演变成现在的咸水生长植物.最后,提出了在川蔓藻属未来研究中有待进一步解决的问题.     

The pharyngeal jaw apparatus of labrid fishes: A functional morphological perspective

Among the acanthopterygian fishes, the Labridae possess the most highly integrated and specialized pharyngeal jaw apparatus. The integrated feature involves many osteological components and aspects of muscle form, architecture, composition, and function. The upper jaw articulates by means of a true diarthrosis with the pharyngeal process of the parasphenoid, whereas the lower jaw has established physical contact with the cleithrum. Complex muscle fusions have contributed significantly in the development of a double muscle sling operating the lower jaw. The original levator externus 4 fuses with the central head of the obliquus posterior, whereas the original levator posterior combines with the lateral head of the obliquus posterior as well as with the adductor branchialis 5. During the masticatory cycle, both upper and lower jaws undergo complex movement orbits resulting in shearing and crushing functions. Shearing occurs as the forward moving upper jaw collides with the dorsally held lower jaw. Crushing is effected by an extreme posterodorsal movement of the lower jaw against the retracted upper jaw, thereby establishing full occlusion of the teeth. The specialized morphological and functional design of the labrid pharyngeal jaw apparatus is similar to that found in cichlids. In sharp contrast to primitive acanthopterygian fishes, the Labridae and Cichlidae exhibit a spectacular morphological diversity that parallels their ecological diversification. Our combined functional and historical analysis has established a correlation between the complex integration of the pharyngeal jaw apparatus and morphological and ecological diversity in the Labridae and Cichlidae.     

Cholesterol accumulation in prostate cancer: A classic observation from a modern perspective

Prostate cancer (PCa) is the most common cancer in men in developed countries. Epidemiological studies have associated high blood-cholesterol levels with an increased risk of PCa, whilst cholesterol-lowering drugs (statins) reduce the risk of advanced PCa. Furthermore, normal prostate epithelial cells have an abnormally high cholesterol content, with cholesterol levels increasing further during progression to PCa. In this review, we explore why and how this occurs.     

A phylogenetic and biogeographic perspective on the evolution of poeciliid fishes

Phylogenetic relationships of members of the subfamily Poeciliinae (Cyprinodontiformes) are investigated to test alternate hypotheses of diversification resulting from the assembly of the Central America and the Caribbean from the Cretaceous period onwards. We use 4333 aligned base pairs of mitochondrial DNA and 1549 aligned base pairs of nuclear DNA from 55 samples representing 48 ingroup and seven outgroup species to test this hypothesis. Mitochondrial genes analyzed include those encoding the 12S and 16S ribosomal RNAs; transfer RNAs coding for valine, leucine, isoleucine, glutamine, methionine, tryptophan, alanine, asparagine, cysteine and tyrosine; and complete cytochrome b and NADH dehydrogenase subunit I and II; nuclear gene analyzed included the third exon of the recombination activation gene 1 (RAG1). Analyses of combined mtDNA and nuclear DNA data sets result in a well-supported phylogenetic hypothesis. This hypothesis is in conflict with the classical taxonomic assignment of genera into tribes and phylogenetic hypotheses based on the taxonomy; however, the molecular hypothesis defines nine clades that are geographically restricted and consistent with the geological evolution of Central America and the Caribbean. Our analyses support multiple colonization events of Middle America followed by a mix of vicariance and dispersal events.     

鱼类亲代抚育行为的研究进展

亲代抚育行为（parental care behavior）是指动物对其后代或其亲缘后代提供保护和养育的所有活动,属于本能行为的一种,广泛存在于动物界之中。鱼类在其为数不多的科中充分发展了几乎所有类型的亲代抚育行为,因而成为研究该行为的最佳物种之一。随着威廉斯原理（Williams’s Principle）的提出和应用,人们对鱼类亲代抚育行为的探索逐步由定性向定量发展,普遍认同了在鱼类进化中,雄性抚育模式得以占据支配地位的缘由并非是因为雄性在抚育活动中获得了较多的利益,而是由于在获取相同利益时雄性损失的未来投资成本较雌性低的观点。近年来的研究证实,在亲代抚育过程中存在着某种动态调整机制,其中四个比较关键的影响因素分别为：亲本所抚育的子代数量、亲本先前的投资、亲本与被抚育子代间的遗传关联度和亲本未来的交配机会。     

A specification of numerical taxonomy: Thermodynamical taxonomy

Thermodynamic taxonomy (ThT) is established from both a theoretical and pragmatical point of view. An application of thermodynamic taxonomy is given.     

Fluctuating asymmetry and exogenous stress in fishes: a review

Fluctuating asymmetry (FA), which has been examined in a variety of plants and animals, is widely promoted as a useful bioindicator of exogenous stressors in habitats, whether of natural or anthropogenic origin. Wildlife managers and researchers often use a specific group of organisms as an indicator of the health of a given habitat. The purpose of this review is to demonstrate that FA can be an effective fish biomonitoring tool by presenting a vote counting meta-analysis of 81 fish FA studies published between 1966 and the first half of 2009. The vote counts were analyzed with the G test for independence to determine whether the probability of observing significant morphological asymmetry is determined by character type, exogenous stressor type, or fish order. The information obtained from these papers and their analysis is then used to outline areas in which FA studies can be improved: (1) carefully considering character choice; (2) distinguishing between asymmetry types; (3) determining the level of measurement error in between-sides character variation; (4) determining baseline FA levels in populations; (5) increasing the number of laboratory studies which corroborate field observations of FA; (6) conducting true replications of studies to validate previous findings. Only with more critical experimental design and data analysis can FA be used as a powerful tool for assessing environmental degradation.