The distribution of capillaries in the somatic musculature of two vertebrate types with particular reference to teleost fish

The distribution of capillaries in teleost and rat striated muscles was investigated using a number of different methods. A new method for directly viewing capillaries was developed. Teleost white muscle has a capillary: fibre (C:F) ratio of between 0.2 and 0.3; and 0.6 to 1.0 peripheral capillaries per muscle fibre. 26-49% of fibres had no peripheral capillaries. Values for the rat gastrocnemius were 1.2, 2.6 and 4.8% respectively which compares well with literature values. Flathead red muscle had a C:F ratio of between 1.9 and 2.5; and between 5.3 and 6.6 peripheral capillaries per muscle fibre depending on the method used. Values for rat soleus were 1.8 and 4.1 respectively. Teleost pink fibres had an intermediate number of capillaries. Rat striated muscle, particularly the gastrocnemius, was found to be heterogeneous with respect to the distribution of capillaries. Flathead red muscle was homogeneous whilst teleost white muscle was only slightly variable. Flathead red muscle fibres are well suppled with subsarcolemmal mitochondria. These show a clumped distribution corresponding to the position of capillaries. In contrast teleost white fibres are almost totally devoid of these and all other mitochondria. No differences were observed in the vascularisation of either muscle type along the length of the fish. The results are discussed in relation to the division of labour between fibre types during swimming.     

Serine proteinase inhibitors of seminal plasma of teleost fish: distribution of activity, electrophoretic profiles and relation to proteinase inhibitors of blood

Anti-proteinase activity has been found in seminal plasma of eight teleost fish species: brown trout, rainbow trout, brook trout, lake whitefish, bream, northern pike, Danube salmon and burbot. This activity correlated with seminal plasma protein and sperm concentrations. Using a mammalian (bovine) trypsin for detecting proteinase inhibitors it was found for the first time that there are species-specific electrophoretic profiles of anti-proteinase activity. One to three bands could be identified by this method. However, additional proteinase inhibitors could be identified by using fish (cod) trypsin. These inhibitors were detected in seminal plasma of salmonids and coregonids and have a slow migration rate. Fast-migrating proteinase inhibitors were present in rainbow, brown and brook trout, northern pike, whitefish and burbot. These inhibitors could be detected in brook and brown trout by using either trypsins. However, they were detected only with bovine trypsin in rainbow trout, northern pike, whitefish and burbot. These results suggest that multiple forms of serine proteinase inhibitors exist in seminal plasma of teleost fish and they differ in their affinity toward serine proteinases. Seminal plasma serine proteinase inhibitors of rainbow trout migrated during electrophoresis similarly to blood plasma proteinase inhibitors, and suggests that the two inhibitors may be similar or the same. Anti-proteinase specific activity was similar in blood and seminal plasma. Proteinase inhibitors of fish seminal plasma seem to be an important part of sperm physiology, possibly related to protection of spermatozoa. Staining for detection of serine proteinase inhibitors also allowed detection of presence of nonspecific esterase in seminal plasma of most species.     

Types and development pathways of lateral line scales in some teleost species

Voronina, E.P. and Hughes, D.R. 2011. Types and development pathways of lateral line scales in some teleost species. —Acta Zoologica (Stockholm) 00 : 1–13. A comparative study of lateral line scales (lls) in nine teleost species was undertaken to trace their ontogenetic structural changes. Three universal characters were used to describe and classify definitive and developing lls. The four main structural types in teleosts are represented. In adult fish, lls are the same structural type in all parts of lateral line in any one specimen, but number of tubules and their orientation may vary. In juvenile fish, except for one species, the structural type of every lls changes with growth, and this process progresses along the lateral line in the direction of development typical for the species. Definitive structural type of the lls is not determined by common scale type and size, presence or absence of nerve foramen on lls, scale overlapping or time of initiation of scales and trunk canal. Development pathways are proposed in which terminal states correspond to the final development of the most complex lls type in Cyprinus carpio, Carassius carassius, Oncorhynchus mykiss, Diplodus annularis and Mullus barbatus. The intermediate states of these pathways correspond to other types of lls as examples of pedomorphosis in Perca fluviatilis, Sander lucioperca, Symphysodon aequifasciatus and Hippoglossoides platessoides.     

闽南-台湾浅滩渔场地形及水深与中上层鱼类群聚分布的关系

根据闽南－台湾浅滩渔场灯光围网信息船1989－1999年的渔捞纪录,研究闽南－台湾浅滩渔场海底地形,水深与中上鱼类群聚的关系。结果表明,渔场地形起伏,水深变化大,中上层鱼类分布较为密集,但各渔区间的分布不均匀,南北方向上渔获产量分布是由北向南递增,东西方向上渔获产量分布是由浅滩两侧向浅滩的南,北中部靠拢;中上层鱼类主要分布在海峡南部混合水和海峡暖水区,其中心渔场位于上升流终年存在的高盐区,同时群聚于海底断裂区和海底隆起边缘区;中上层鱼类群聚区或中心渔场随海峡南部混合水和海峡暖水的季节变化而变化,不仅与渔场地形,水深有关,还与影响海区季风的风向,风力和不同水系强弱有关;本渔场中上层鱼类在不同季节群聚水深,春,夏季为30－60m,秋,冬季为40－80m。     

Fibre types in the locomotory muscles of an antarctic teleost,Notothenia rossii

Summary The metabolic and structural differentiation of locomotory muscles of Notothenia rossii has been investigated. In this species sustained locomotion is achieved by sculling with enlarged pectoral fins (labriform locomotion), whilst the segmental myotomal muscle is reserved for burst activity. Red, white and subepidermal fibres can be distinguished in the trunk by histochemical and ultrastructural criteria. The main pectoral muscle (m. adductor profundus) consists entirely of red fibres. These three main fibres types show differences in histochemical staining profiles, capillarization, myofibril shape and packing, and lipid and mitochondrial content. The fractional volume of mitochondria amounts to 38% for pectoral, 30% for red myotomal and 1.9% for white myotomal fibres. Enzyme activities of red pectoral muscle are consistent with a higher potential for aerobic glucose and fatty acid oxidation than for the red myotomal fibres. Mg²⁺ Ca²⁺ -myofibrillar ATPase activities are similar for red pectoral and myotomal muscles and approximately half of those white fibres. Specialisations of N. rossii muscles associated with labriform swimming and locomotion at Antarctic temperatures are discussed.     

Sea warming and fish distribution: the case of the small pelagic fish, Sardinella aurita, in the western Mediterranean

This study analyses the temporal and spatial changes in abundance and distribution of the warm water species round sardinella (Sardinella aurita) in the western Mediterranean over the last decades in relation to sea water temperature. In the western Mediterranean basin (1950–2003), a significant positive relationship was found between round sardinella landings and temperature anomalies. Along a latitudinal gradient off the Mediterranean Iberian coast (1989–2004), a gradual increase in species abundance was observed from south to north, with a certain time lag going northwards, associated with the increase in sea water temperature. The abundance of round sardinella in the two warmest and southernmost areas was positively and significantly correlated with sea surface temperature registered during the start of gonad maturation the previous year. In addition, the positive relationship established between water temperature and abundance of round sardinella in the coldest and northernmost study area demonstrates that there is a temperature limit for the distribution of this species in the western Mediterranean. In addition, this study analyses round sardinella larvae distribution and abundance in the summers of 2003 and 2004, and conducts a comparison with the situation 20 years ago (summer 1983). Results show a marked increase in larval abundance during the last decades and the present appearance of larvae in the northernmost study areas, where they did not occur 20 years ago. This indicates the successful reproduction of round sardinella in the northern part of the Mediterranean, where the species has expanded, confirming its establishment in the area.     

Morphology, histochemistry, and function of epaxial cervical musculature in the horse (Equus caballus).

The semispinalis capitis and splenius muscles of the horse were analyzed for gross morphology, microarchitecture, fiber length, and fiber type. Although these two muscles are similar in size and anatomical position, they are very different from one another in structural design and histochemistry, implying diverse functional roles in the animal's behavior. The histochemical staining profile was limited to two fiber types: slow oxidative and fast glycolytic. The splenius muscle has simple architecture, long fibers, and a 60/40 ratio of SO to FG cross-sectional area. The semispinalis capitis has complex architecture with short-fibered, concentric compartments dorsal to its central tendon and longer-fibered compartments ventrally. The entire dorsal region has an increasing gradient of slow oxidative fiber percentage from caudal to cranial (58-71% SO). In contrast, the ventral region has a decreasing gradient of slow oxidative fibers from caudal to cranial (48-67% FG). These patterns can be interpreted within the context of the cervical musculature during locomotion and posture to indicate the functional advantages of this organization.     

Age‐related changes in stem cell dynamics,neurogenesis, apoptosis,and gliosis in the adult brain: A novel teleost fish model of negligible senescence

Adult neurogenesis, the generation of new neurons in the adult central nervous system, is a reported feature of all examined vertebrate species. However, a dramatic decline in the rates of cell proliferation and neuronal differentiation occurs in mammals, typically starting near the onset of sexual maturation. In the present study, we examined possible age‐related changes associated with adult neurogenesis in the brain of brown ghost knifefish (Apteronotus leptorhynchus), a teleost fish distinguished by its enormous neurogenic potential. Contrary to the well‐established alterations in the mammalian brain during aging, in the brain of this teleostean species we could not find evidence for any significant age‐related decline in the absolute levels of stem/progenitor cell proliferation, neuronal and glial differentiation, or long‐term survival of newly generated cells. Moreover, there was no indication that the amount of glial fibrillary acidic protein or the number of apoptotic cells in the brain was altered significantly over the course of adult life. We hypothesize that this first demonstration of negligible cellular senescence in the vertebrate brain is related to the continued growth of this species and to the lack of reproductive senescence during adulthood. The establishment of the adult brain of this species as a novel model of negligible senescence provides new opportunities for the advancement of our understanding of the biology of aging and the fundamental mechanisms that underlie senescence in the brain. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 74: 514–530, 2014     

Pelagic cephalopods from eastern Australia: species composition, horizontal and vertical distribution determined from the diets of pelagic fishes

The distribution and relative biomass of cephalopods from pelagic waters off eastern Australia was examined between 1997 and 2004 from stomach contents of swordfish, yellowfin tuna and dolphinfish taken in the domestic longline fishery. A total of 38 taxa from 19 families were identified. Comparison of the species composition of the three predators indicated pronounced differences in cephalopod species composition. In swordfish, species of the family Ommastrephidae, particularly Ommastrephes bartramii (Lesueur 1821) and Nototodarus gouldi (McCoy 1888) dominated, whereas a more diverse mix of species was identified from yellowfin-sampled cephalopods. Todaropsis eblanae (Ball 1841) was the main cephalopod sampled from the surface-dwelling dolphinfish. For swordfish-sampled cephalopods, significant relationships were found between biomass and season, fluorescence and year. In yellowfin tuna, cephalopod biomass was significantly correlated with season, area and sea surface temperature. Significant factors differed between predator-sampler, possibly reflecting the limits of the predator, but could also give insights into individual cephalopod species distributions. However, the increase in cephalopod biomass over summer in both swordfish and yellowfin tuna suggested cephalopod biomass was higher over summer in the region.     

Effects of calcium and phosphate on the corpuscles of Stannius of the teleost fish,Oreochromis mossambicus

Summary Removal of the corpuscles of Stannius (CS) in Oreochromis mossambicus leads to hypercalcemia and hypophosphatemia. The effects on CS size and ultrastructure of different calcium and phosphate concentrations of the ambient water and of the food were investigated. A six-fold increase of the calcium concentration of the water leads to a four-fold increase in CS volume; this is mainly caused by an increase in the size and number of the type-1 cells. The effect of external calcium is most probably mediated by the calcium concentration of the blood plasma. Plasma ionic calcium may be the relevant factor. Changes in the calcium concentration of the food had no effect on the CS. Similarly, hyperphosphatemia or hypophosphatemia induced by high phosphate concentrations of the water or the food, or by a phosphate-deficient diet, had no noticeable effect on the CS. The results support the hypothesis that the type-1 cells produce the hypocalcemic factor of the CS. There is no evidence for the production by the CS of an endocrine factor involved in the control of phosphate metabolism.     

Neuronal and synaptic organization of the lateral geniculate nucleus of the tree shrew,Tupaia glis

Summary The ultrastructural study of the lateral geniculate nucleus (LGN) of the tree shrew (Tupaia glis) revealed two types of neurons: (1) a large thalamocortical relay cell (TCR), which may bear cilia, and (2) a small Golgi type-II interneuron (IN) with an invaginated nucleus. The narrow rim of pale cytoplasm of the IN contains fewer lysosomes and fewer Nissl bodies than the cytoplasm of the TCR. The IN perikarya, which in some cases establish somatosomatic contacts, frequently contain flattened or pleomorphic synaptic vesicles. The ratio of TCR to IN is 31.Three types of axon terminals were observed in the LGN. Two of them contain round synaptic vesicles but differ in size. The large RL boutons undergo dark degeneration after enucleation; they are the terminals of retino-geniculate fibers. The smaller RS boutons show dark degeneration after ablation of the visual cortex; they are the terminals of the cortico-geniculate fibers. The third type of bouton (F₁ does not degenerate after either intervention. The boutons of this type are filled with flattened vesicles and are believed to be intrageniculate terminals. F₂-profiles were interpreted as presynaptic dendrites of the IN. The characteristic synaptic glomeruli found in the LGN contain in their center an optic terminal. These optic terminals establish synaptic contacts with dendrites or spine-like dendritic protrusions of TCRs as well as with presynaptic dendrites. Synaptic triads were also seen. The distribution of the individual types of synaptic contacts in layers 3 and 4 was determined. Layer 4 contains only one third of the retino-geniculate synapses and of the synaptic contacts of F₁-terminals.     

Combining stereo‐video monitoring and physiological trials to estimate reef fish metabolic demands in the wild

Organismal metabolic rates (MRs) are the basis of energy and nutrient fluxes through ecosystems. In the marine realm, fishes are some of the most prominent consumers. However, their metabolic demand in the wild (field MR [FMR]) is poorly documented, because it is challenging to measure directly. Here, we introduce a novel approach to estimating the component of FMR associated with voluntary activity (i.e., the field active MR [AMRfield]). Our approach combines laboratory‐based respirometry, swimming speeds, and field‐based stereo‐video systems to estimate the activity of individuals. We exemplify our approach by focusing on six coral reef fish species, for which we quantified standard MR and maximum MR (SMR and MMR, respectively) in the laboratory, and body sizes and swimming speeds in the field. Based on the relationships between MR, body size, and swimming speeds, we estimate that the activity scope (i.e., the ratio between AMRfield and SMR) varies from 1.2 to 3.2 across species and body sizes. Furthermore, we illustrate that the scaling exponent for AMRfield varies across species and can substantially exceed the widely assumed value of 0.75 for SMR. Finally, by scaling organismal AMRfield estimates to the assemblage level, we show the potential effect of this variability on community metabolic demand. Our approach may improve our ability to estimate elemental fluxes mediated by a critically important group of aquatic animals through a non‐destructive, widely applicable technique.     

Population dynamics of two small pelagic fish in the central-south area off Chile: delayed density-dependence and biological interaction

It is widely believed that environmental variability is the main cause for fluctuations in commercially exploited small pelagic fish populations around the world. Nevertheless, density-dependent factors also can drive population dynamics. In this paper, we analyzed thirteen years of a relative abundance index of two clupeoids fish populations coexisting in the central-south area off Chile, namely the common sardine, Strangomera bentincki, and anchovy, Engraulis ringens. We applied the classical diagnostic tools of time series analysis to the observed time-series. Also, the realized per capita population growth rate was studied with the aim of detecting the feedback structure that is characterizing the population dynamics of the two species. The analysis suggests that population fluctuations of the two species have an important density-dependent component, displaying first-order (direct density-dependent) and second-order (delayed density-dependent) simultaneously. The density-dependent component explained 70.5 and 55.6 % of the realized per capita population growth rate of common sardine and anchovy, respectively. The deterministic skeleton model showed an asymptotic convergence to equilibrium density. In presence of a stochastic environment, fluctuations were reproduced for the species showing a component of fluctuation with a period of 4 year. The intrinsic dynamics of each species is typical of interacting species resulting from trophic interactions. It is postulated that the second-order dynamics of S. bentincki and E. ringens in central-south Chile, may be the result from interactions with a specialist predator (the fishing fleet), interacting with exogenous environmental factors.     

Unique features of pedicellate attachment of the upper jaw teeth in the adult gobiid fish Sicyopterus japonicus (Teleostei,Gobiidiae): Morphological and structural characteristics and development

Sicyopterus japonicus (Teleostei, Gobiidae), a hill‐stream herbivorous gobiid fish, possesses an unusual oral dentition among teleost fishes on account of its feeding habitat. By using scanning electron microscopy, light microscopy, and transmission electron microscopy, including vital staining with tetracycline, we examined the development of the attachment tissues of the upper jaw teeth in this fish. The functional teeth of S. japonicus had an asymmetrical dentine shaft. The dentine shaft attached to the underlying uniquely shaped pedicel by means of two different attachment mechanisms. At the lingual base, collagen fiber bundles connected the dentine shaft with the pedicel (hinged attachment), whereas the labial base articulated with an oval‐shaped projection of the pedicel (articulate attachment). The pedicel bases were firmly ankylosed to the crest of the thin flange of porous spongy bone on the premaxillary bone, which afforded a flange‐groove system on the labial surface of the premaxillary bone. Developmentally, the pedicel and thin flange of spongy bone were completely different mineralized attachment tissues. The pedicel had a dual origin, i.e., the dental papilla cells, which differentiated into odontoblasts that constructed the internal surface of the pedicel, and the mesenchymal cells, which differentiated into osteoblasts that formed the outer face of the pedicel. A thin flange of spongy bone was deposited on the superficial resorbed labial side of the premaxillary bone proper, and later rapid bone remodeling proceeded toward the pedicel base. These unique features of pedicellate tooth attachment for the upper jaw teeth in the adult S. japonicus are highly modified teeth for enhancing the ability of individual functional teeth to move closely over irregularities in the rock surfaces during the scraping of algae. J. Morphol., 2013. © 2012 Wiley Periodicals, Inc.     

The distribution and abundance of young fish in the Banc d'Arguin,Mauritania

The importance of the Banc d'Arguin (Mauritania) for juvenile fish has been investigated in September 1988. Fish have been sampled with a 2 m beam trawl at 50 locations in the coastal zone between Cap Sainte Anne and Cap Timiris. Water depth varied between 1 and 16 metres. Temperature and salinity at each station have been measured, as well as the weight of the catch and total length of the individual fish. The largest catches — in numbers as well as in weight — were obtained around the shallows of Tidra and Arel. This region has a large diversity in species, and contains large numbers of juvenile fish and cephalopods. The deeper areas seem to be much poorer in species, but average length and weight of the sampled fish are higher than around Tidra and Arel.     

Thermosensitive ion channel TRPV1 is endogenously expressed in the sperm of a fresh water teleost fish (Labeo rohita) and regulates sperm motility

Sperm cells exhibit extremely high sensitivity in response to slight changes in temperature, osmotic pressure and/or presence of various chemical stimuli. In most cases throughout the evolution, these physico-chemical stimuli trigger Ca²⁺-signaling and subsequently alter structure, cellular function, motility and survival of the sperm cells. Few reports have recently demonstrated the presence of Transient Receptor Potential (TRP) channels in the sperm cells from higher eukaryotes, mainly from higher mammals. In this work, we have explored if the sperm cells from lower vertebrates can also have thermo-sensitive TRP channels. In this paper, we demonstrate the endogenous presence of one specific thermo-sensitive ion channel, namely Transient Receptor Potential Vanilloid family member sub type 1 (TRPV1) in the sperm cells collected from fresh water teleost fish, Labeo rohita. By using western blot analysis, fluorescence assisted cell sorting (FACS) and confocal microscopy; we confirm the presence of this non-selective cation channel. Activation of TRPV1 by an endogenous activator NADA significantly increases the quality as well as the duration of fish sperm movement. The sperm cell specific expression of TRPV1 matches well with our in silico sequence analysis. The results demonstrate that TRPV1 gene is conserved in various fishes, ranging from 1–3 in copy number, and it originated by fish-specific duplication events within the last 320 million years (MY). To the best of our knowledge, this is the first report demonstrating the presence of any thermo-sensitive TRP channels in the sperm cells of early vertebrates as well as of aquatic animals, which undergo external fertilization in fresh water. This observation may have implications in the aquaculture, breeding of several fresh water and marine fish species and cryopreservation of fish sperms.     

基于eDNA metabarcoding探究北京市主要河流鱼类分布及影响因素

使用eDNA宏条形码(eDNA metabarcoding)和地笼法检测了北京市3条水系在夏季和秋季两个季节的鱼类多样性, 旨在研究北京市鱼类群落的空间格局特征, 探索适用于北京鱼类生物多样性监测及保护的新方法。结果表明: 在北京市的34个采样点中, 利用eDNA metabarcoding共检测出鱼类55种, 显著高于传统方法所捕获的鱼类种数(35种), 鱼类组成以鲤形目和鲈形目为主。山区河流清水鱼的多样性要显著高于城区河流, 城区河流(北运河水系)群落结构较为单一, 以鲫(Carassius auratus)、麦穗鱼(Pseudorasbora parva)、泥鳅(Misgurnus anguillicaudatus)等耐污种为优势种; 山区河流(潮白河水系及大清河水系)以宽鳍鱲(Zacco platypus)、拉氏鱥(Rhynchocypris lagowskii)、马口鱼(Opsariichthys uncirostris)等为优势种。不同季节影响清水鱼群落结构的环境因子不同, 夏季主要是总溶解固体和电导率, 秋季主要是海拔和温度。清水鱼丰富度与环境因子及人类活动的相关性表明, 清水鱼的丰富度随着总溶解固体及灯光指数增加而显著降低, 且均与海拔、温度等存在显著相关性。本研究证明了eDNA metabarcoding方法用于监测北京市鱼类多样性及其时空分布的可行性。     

Free amino compounds and cell volume regulation in erythrocytes from different marine fish species under hypoosmotic conditions: the role of a taurine channel

Erythrocytes from the marine fish species ballan wrasse (Labrus berggylta Ascanius), bullhead (Myoxocephalus scorpius L.), cod (Gadus morhua L.), dab (Limanda limanda L.), eelpout (Zoarces viviparus L.), flounder (Platichthys flesus L.), lumpfish (Cyclopterus lumpus L.), plaice (Pleuronectes platessa L.), sole (Solea solea L.) and turbot (Scophthalmus maxima L.) possess the capacity for regulatory volume decrease. This property was demonstrated in vitro by reduction of the osmolality of the incubation medium from 330 to 255 mosmol·kg^-1. During the 4-h incubation period only the lumpfish cells completely regained the original volume. Twenty-seven free amino compounds were present in detectable amounts in the erythrocytes. At normal osmolality the taurine content was between 14.0 mol·g dry weight^-1 (lumpfish) and 147.4 mol·g dry weight^-1 (sole). Except in the bullhead, taurine was the quantitatively dominating amino compound in the erythrocytes from all species, and accounted for betwee 23% (lumpfish) and 88% (sole) of the total content of free amino compounds. In each species the regulatory volume decrease was associated with a reduction in the cellular content of taurine. Taurine contributed to between 6% (lumpfish) and 36% (flounder) of the cell shrinkage. There was a significant negative correlation, however, between the cellular concentration of taurine at normal osmolality and the capacity of the cells for regulatory volume decrease. Gamma-aminobutyric acid and/or glycine also contributed to the process of volume regulation, but to a lesser extent than taurine. The volume regulatory efflux of taurine and -aminobutyric acid were mediated by taurine channels. It is suggested that these channels also mediated the reduction in the cellular contents of glycine.Abbreviations cmp counts per minute - dw dry weight - GABA -amino-n-butyric acid - MW molecular weight - SD standard deviation - ww wet weight