Age, Growth, and Sexual Development in the Self-fertilizing Hermaphroditic Fish Rivulus marmoratus

We studied age, growth, and sexual development in the early life intervals of the self-fertilizing mangrove killi-fish, Rivulus marmoratus. Newly hatched (day 0) individuals had sagittal otoliths of 60m radius, with about 30 increments. Sequential sampling until about day 60 after hatching yielded otoliths with the number of increments outside the 60m radius equal to the daily age of the fish. Alizarin complexone marking of otoliths also confirmed the increments were daily, and demonstrated the applicability of this technique to field studies for capture-mark-recapture, or age and growth estimates. Individuals fed a restricted amount of food formed fewer daily otolith growth increments than fish fed to satiation each day. Using histological analysis for identifying gonad morphogenesis, we found no correlation between gonadal development and external appearance (caudal ocellus, orange fin colouration) in young fish of known ages. The caudal ocellus was not present until 9mm total length, and developed thereafter. Of 136 individuals examined, fish less than 17.2mm total length (TL, n = 124) were females. Testicular tissue first appeared among individuals 17–18mm TL (n = 3), while some individuals greater than 18mm TL (n = 8) were functional hermaphrodites. The single male in our study was relatively of small body size (9.6mm, day 37) with a distinct caudal ocellus, indicating that it is presumably a primary male.     

Forensic biological pursuits of exotic fish origins: piranha in Hawaii

Synopsis The otoliths of an adult red-bellied piranha, Pygocentrus nattereri, captured from a reservoir in Hawaii were scrutinized to determine the fish's origin and growth history. Sagittal otoliths of the piranha, P. nattereri, contained internal microincrements visible by Scanning Electron Microscopy. The medial cross sectional plane of the sagitta was resolved to provide counts for the most visible micro-increments. An opportune spawning of confiscated adults provided samples for verification of daily increment formation. Daily formation of microincrements was verified from hatched individuals, and confirmed the suitability of otoliths for revealing daily patterns in the age and growth of piranhas. The central area of the sagitta was diffuse in regards to otolith microstructure and indicated the fish was held in an unchanging environment (aquarium). Therefore, otoliths provide important life history or forensic information incorporated within their structural components. The visualization of daily microincrements in the otolith of a juvenile allowed the determination of age at and since release. Fish grew rapidly after being released into the wild. From otolith increments the date of release for an individual fish can be calculated with acceptable accuracy. As presented, otolith structural information can provide age and growth data which are essential to the management of introduced species.     

Evidence of downstream migration of Sakhalin taimen, <Emphasis Type="Italic">Hucho perryi</Emphasis>, as revealed by Sr : Ca ratios of otolith

The migratory history of Sakhalin taimen, Hucho perryi, was examined in terms of strontium (Sr) and calcium (Ca) uptake in the otolith by using wavelength dispersive X-ray spectrometry on an electron microprobe. Otolioth Sr:Ca ratios of freshwater-reared samples remained consistently at low levels throughout the otolith. The Sr:Ca ratios of samples from Lake Aynskoye of Sakhalin Island showed a low value from the core up to a point of 700–2140µm. Thereafter, the ratios increased sharply and remained at higher levels up to the outermost regions. The difference in Sr:Ca ratio might be the result of the presence of individuals that underwent seawater and freshwater life history phases, probably reflecting the ambient salinity or the seawater–freshwater gradient in Sr concentration. Otolith Sr:Ca ratio analysis revealed downstream migration history in H. perryi.     

Estimating the age of Antarctic larval fish from otolith microstructure using light and electron microscopy

Larval fish of Antarctica have very narrow rings on their otoliths (<1 m) that may not be resolved with light microscopy. In this study, age data from the otoliths of larval Nototheniidae (Gobionotothen gibberifrons and Lepidonotothen larseni), determined using light and scanning electron microscopy, are compared. Rings 0.4 m wide were observed on otoliths viewed under electron microscopy; however, light microscopy could only resolve rings 0.5 m wide. Scanning electron microscopy is more time consuming and costly than light microscopy but has greater resolving power and is recommended to validate ring counts made using light microscopy in otolith studies with Antarctic larval fish.     

Determination of the freshwater mark in otoliths of Japanese eel elvers using microstructure and Sr/Ca ratios

The microstructure, in particular checks within the otolith edge, of Anguilla japonica glass-eels and elvers and changes in otolith Sr/Ca ratios were examined to ascertain the environmental history of the eels, especially with regard to the time when glass-eels entered the river, and as a benchmark for count daily increments. The percentage of glass eels and elvers with checks and the mean number of checks within the otoliths of glass-eels caught at four localities, Tosa Bay off Tosa City, the mouth of the Gokase River, the mouth of the Saigo River and the dam of the Tsuri River were 0% (0), 15.0% (0.2), 51.6% (1.0) and 100.0% (4.2), respectively. The Sr/Ca ratios and Sr content peaked in the region where checks were formed and the values decreased rapidly towards the edge of the checks; on the other hand, these decreased gradually in the otolith when checks were not formed. These checks were estimated to be formed by stress when the glass-eels were affected by ambient fresh water within the river. The innermost check was called the freshwater mark in the present study and this mark may be useful as a benchmark in studying the growth history of the eel before and after entering freshwater.     

Growth of Juvenile Centropomus undecimalis in a Tropical Island

Age, growth rates and hatching dates were determined for juvenile common snook, Centropomus undecimalis, collected in several Puerto Rican estuarine systems. Two growth models (von Bertalanffy and power curve) were used and compared based on the fitting, the residual distribution and homogeneity of variances. A multiple linear regression was also fit to predict age from otolith weight, fish weight and standard length. Hatching dates back-calculated from age estimates, suggested that spawning occurs throughout the year but peaks from May to October. Early juveniles (age < 100d) recruited during the wet season (August to November) showed a significantly higher growth rate (0.67mmd^–1) than the dry season (December to July) recruits (0.41mmd^–1). These results are compared with snook collected in west Florida.     

Cathodoluminescence Microscopy: A Useful Tool for Assessing Incremental Chemical Variation in Otoliths

Otoliths taken from fish from Eden Lake, Manitoba show yellow–green and red cathodoluminescence of varying intensity that corresponds to their annular structure. Proton-induced X-ray emission analysis shows manganese (Mn) concentrations of between 2 and 205ppm, zinc (Zn) concentrations between 2 and 290ppm and strontium (Sr) concentrations up to 1500ppm in the otoliths. The distribution of luminescence correlates with the distribution of Mn. The Mn, Zn and Sr are likely derived from the monzonitic rocks surrounding the lake. Variations in the distribution of cathodoluminescence may be a useful tool for evaluating changes in environmental chemistry and fish life histories.     

Trophic Assemblages of the Rocky Intertidal Zone in Vostok Bay,Sea of Japan

The ratios between the indices of relative abundance for different trophic life forms have been used to characterize bionomical types of a rocky intertidal zone. It has been shown that the distribution of life forms is determined by the geomorphological peculiarities of the surveyed intertidal areas. A brief critical historical review has been provided of the terms bionomy and bionomical type.     

Ultrastructure of four types of striated muscle fibers in the atlantic hagfish (Myxine glutinosa,L.)

Summary Four types of striated muscle fibers with distinctive ultrastructure were defined in the Atlantic hagfish (Myxine glutinosa, L.): white, intermediate, and red fibers of m. parietalis, and red fibers of m. craniovelaris.White fibers are thick, contain very few mitochondria and fat vacuoles, and possess distinct and separate myofibrils with thin Z-disks and distinct M-lines. Intermediate fibers are thinner, possess largely similar myofibrils that often are even better separated due to a higher content of fat vacuoles and especially mitochondria and glycogen granules. Red fibers of m. parietalis contain large amounts of mitochondria, fat vacuoles, and glycogen granules. Their myofibrils possess M-lines, and although branching more, the myofibrils of red fibers conform with a Fibrillenstruktur pattern like those of white and intermediate fibers. Red fibers of m. craniovelaris are very thin, possess many smaller fat vacuoles, and large amounts of mitochondria and glycogen granules. The myofibrils are significantly thinner than in m. parietalis fibers, run as quite independent well separated units, possess thicker Z-disks, and lack M-lines. Large amounts of myosatellite cells are associated with these red fibers.Triads are located near A/I-junctions in all four fiber types and occur irregularly, the density of triads being different in the various fiber types.We are indebted to Dr. Finn Walvig, Biological Station, University of Oslo, Drøbak, for supply of hagfishes, and we also wish to thank Dr. Jan K. S. Jansen, Institute of Physiology, University of Oslo, for valuable suggestions during this study.     

Coexistence of Anadromous and Resident Life History Styles of Pond Smelt, <Emphasis Type="Italic">Hypomesus nipponensis</Emphasis>, in Lake Ogawara,Japan, as determined by Analyses of Otolith Structure and Strontium:Calcium Ratios

Anadromous and resident forms of pond smelt, Hypomesus nipponensis, were found to occur in sympatry in Lake Ogawara, Japan. Profiles of Sr: Ca ratios from individuals could be grouped to two patterns (1) a resident pattern with low Sr: Ca ratios from core to edge and (2) an anadromous pattern with relatively low Sr: Ca ratios near the core with abrupt increases in ratios at a location approximately 0.3mm from the core. Spawners smaller than 60mm standard length (SL) were resident, between 60 to 80mm were mixed resident and anadromous, and larger than 80mm were anadromous. Anadromous individuals first migrated after 40 to 82 days from hatching (mean±sd, 59.1±13.5d) and 14.6 to 30.9mm SL (22.2±5.3mm). There was no difference in SL between resident and anadromous individuals during age at first migration, suggesting that size may not be the mechanism for divergence of alternative life history styles.     

Contribution to the Biology of the Vermilion Snapper, Rhomboplites aurorubens, in Trinidad and Tobago, West Indies

Reproduction and growth of the vermilion snapper, Rhomboplites aurorubens, were studied in Trinidad and Tobago. The smallest individual caught measured 145mm total length (TL) and all fish appeared to be mature. It was not possible to precisely determine size at first maturity due to the use of macroscopic techniques. The smallest spent male and female measured 181 and 211mm TL respectively, suggesting a size at first maturity below these sizes. Spawning occurred throughout the year, with a period of peak spawning from about June to November in the rainy season when river runoff increased. Sagittal otolith sections were used for age determination and the opaque ring, which was counted as the annulus, was deposited from January to May in the dry season. A total of 11 age groups between the ages of 2–12 years (155–505mm total length) were found. The von Bertalanffy growth parameters were: L=532mm, K=0.13y^–1, and t₀=–0.17, where L is the asymptotic length, K is the growth coefficient and t₀ is the theoretical age at zero length. The relationship between weight (WT) and length (TL) was WT=3.43×10^–5 TL^2.82. Vermilion snapper in this study area appears to grow slower and attain a smaller asymptotic length, but has a longer lifespan than found in populations in higher latitudes. This may be attributed to different levels of exploitation, which may be higher in the latter areas.     

Presence of hybridizing DNA sequences homologous to bovine acidic and basicβ-crystallins in all classes of vertebrates

Summary The eye lens-crystallins in cow and chicken are encoded by a family of at least six genes. In order to assess the distribution of the corresponding genes among other vertebrates we hybridized -crystallin sequences (A2, A3/A1, A4, B1, B2, B3), isolated from a bovine lens cDNA library, to Southern blots on whichEcoR1-digested chromosomal DNA was blotted from different vertebrate species. These included human, chimpanzee, calf, rat, pigeon, duck, monitor lizard, toad, trout, and lamprey. Positive hybridization signals were found in the representatives of virtually all classes of vertebrates. The basic B-crystallins gave hybridization signals in more species than the acidic A ones. In monitor lizard and toad the weakest hybridization signals for basic crystallin probes were found. For acidic crystallin probes the distribution pattern was more simple; among cold-blooded vertebrates a signal for A2 was found in trout and lamprey, for A4 in trout, and for A3/A1 only in toad. The results demonstrate that the duplications leading to the -crystallin gene family occurred before or during the earliest stages of vertebrate evolution.     

Cryptic growth in Klebsiella pneumoniae

Summary The ability of Klebsiella pneumoniae to grow on its own soluble lysis products is shown in a series of batch growth experiments. Maximum specific growth rate coefficients ranging from 0.69 to 1.46 h^-1 were obtained with experimental cryptic yield coefficients ranging between 0.42 to 0.52 (mg-cell-C/mg-substrate-C). These kinetic data are used to calibrate a model which demonstrates that depression of theoretical maximum yield coefficients relative to experimentally obtained values can be explained by cryptic growth phenomena without the need to resort to the use of physiologically undefined, mathematical constants. Growth of K. pneumoniae on sonicated cells derived from steady-state chemostat cultures was followed in batch culture and observed to occur with no lag phase. Batch growth curves did not indicate either diauxic or polyauxic growth, suggesting simultaneous utilization of the complex organic substrate mixture. These data suggest that cryptic growth is probably a real event occurring in growing chemostat cultures under ideal growth conditions and most probably also under starvation conditions.     

Peptide des β-Alanins als Ersatz für die freie Aminosäure bei pantothensäurebedürftigen Hefezellen und ihr Verhalten gegenüber dem β-Alanin-Antagonisten Asparagin

Zusammenfassung Pantothensäurebedürftige Hefezellen können ihren Bedarf an diesem Vitamin nicht allein aus -Alanin decken, sondern auch aus Benzoyl--Alanin, -Alanyl-d,l-Norleucin und -Alanyl-l-Histidin. Der Antagonist Asparagin hemmt die Verwertung dieser Peptide genauso wie diejenige der freien Aminosäure. Durch höhere Konzentrationen an -Alanin oder -Alanyl-d,l-Norleucin läßt sich die Hemmwirkung nicht allein kompensieren, es kommt sogar zu einer Förderung des Hefewachstums. Der Antagonist wird dann zum Synergisten.

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Summary The -alanine containing peptides benzoyl--alanine, -alanyl-d,l-norleucine and -alanyl-l-histidine can substitute for the amino acid -alanine in a pantothenic acid requiring yeast. Asparagine, an antagonist of -alanine, affects these peptides in a similar manner. In combination with an overdose of -alanine or -alanyl-d,l-norleucine, asparagine is no longer an antagonist but becomes a synergist.

     

Flora Palinologica Italiana,Sezione Aeropalinologica: S 205 -Pinus pinea L. (Pinaceae)

Summary According to the program Palynological Italian Flora, Aeropalynological section, the pollen morphological card ofPinus pinea L. is presented. The study is carried out on pollen coming from three Italian localities and regards fresh and acetolyzed pollen. For each sample, measurements are carried out on 30 fresh pollen grains in glicerol jelly with fuchsin and on 30 acetolyzed pollen grains in water/glicerol (1/1); general observations regard 1000 fresh and 1000 acetolyzed pollen grains/sample. Some observations on the main differences between fresh and acetolyzed pollen are mentioned.

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Riassunto Nell'ambito della Flora Palinologica Italiana, Sezione Aeropalinologica, è presentata la scheda morfopalinologica diPinus pinea L. nella versione su polline fresco e polline acetolizzato, su tre campioni di diversa provenienza. Vengono notate le principali differenze tra polline fresco e polline acetolizzato.

     

Host length,age, diet,parasites and stable isotopes as predictors of yellow perch (<Emphasis Type="Italic">Perca flavescens</Emphasis>Mitchill), trophic status in nutrient poor Canadian Shield lakes

We used data from parasites and stable isotopes of yellow perch, Perca flavescens, to determine trophic status in four small Canadian Shield lakes as parasites allow the identification of both prey and non-prey dietary components in the host's community. Stable C isotope ratios for all perch ranged from –34 to –19 while stable N isotope ratios ranged from 4.5 to 12.5. These ranges are larger than those observed in many other fish species. Perch age was the most significant predictor of stable C isotope ratio and perch parasite fauna was the most significant predictor of stable N ratios. In particular, parasite fauna indicative of zooplanktivorous or piscivorous perch were most accurate for predicting fish trophic position and thus stable isotope ratio. Fish length and age showed fewer significant relationships with isotope ratios than parasite infracommunity or diet and suggests that trophic category for perch cannot always be predicted based on size.     

Role of βγ-Dimers of GTP-Binding Proteins in Processes of Hormonal Signal Transduction

This review summarizes and analyzes data on structural and functional peculiarities of - and -subunits of heterotrimeric G proteins and their participation in -dimer in processes of hormonal signal transduction to the cell. The molecular mechanisms are discussed, which are responsible for formation of the -dimer complex and its interaction with the wide spectrum of signal and structural proteins, such as G protein -subunit, serpentine type receptors, kinases of G protein-coupled receptors, adenylyl cyclase, phospholipase C2, phosphatidyl-inositol-3-kinase, Raf-kinase, potassium and calcium channels, microtubular and RGS-proteins. The characteristics of - and -subunits are given for living organisms of different phylogenetic levels (lower eukaryotes, fungi, plants, vertebrates, and invertebrates). It is concluded that the -dimer is the most important regulatory link in various signal systems to carry out switch from one signal cascade to another and thereby to determine the final cellular response to the signal impulse.     

Microsampling of Fish Otoliths: A Comparison Between DM 2800 and Dremel in Stable Isotope Analysis

This paper describes and compares two microsampling methods, DM 2800 and Dremel, which were used in taking aragonite samples from otolith zones of cod, Gadus morhua, for stable isotope analysis. There were no significant differences between the two sampling methods both in carbon and oxygen isotope ratios (¹³C/¹²C, ¹⁸O/¹⁶O) and in annual and seasonal otolith zones. The possible finite effect with Dremel could be minimized or negligible by selecting otoliths of younger fishes. Thus, Dremel may be accepted as a convenient microsampling method in stable isotope analysis of otoliths.     

On the sufficiency of the velocity field for perception of heading

All models of self-motion from optical flow assume the instantaneous velocity field as input. We tested this assumption for human observers using random-dot displays that simulated translational and circular paths of movement by manipulating the lifetime and displacement of individual dots. For translational movement, observers were equally accurate in judging direction of heading from a velocity field with a two-frame dot life and a direction field in which the magnitudes of displacement were randomized while the radial pattern of directions was preserved, but at chance with a speed field in which the directions were randomized, preserving only magnitude. Accuracy declined with increasing noise in vector directions, but remained below 2.6° with a 90° noise envelope. Thus, the visual system uses the radial morphology of vector directions to determine translational heading and can tolerate large amounts of noise in this pattern. For circular movement, observers were equally accurate with a 2-frame velocity field, 3-frame acceleration displays, and 2-frame and 3-frame direction fields, consistent with the use of the pattern of vector directions to locate the center of rotation. The results indicate that successive independent velocity fields are sufficient for perception of translational and circular heading.     

Biology of the western minnow,Galaxias occidentalis Ogilby (Teleostei : Galaxiidae), in a south-western Australian river

The size and age composition, growth and diet of the western minnow, Galaxias occidentalis, in the southern branch of the Collie River in south-western Australia were determined from samples collected at approximately monthly intervals between January 1984 and December 1986. The prominent, narrow hyaline zone on otoliths was shown to be formed annually and thus valid for ageing these fish. An examination of the otoliths of 4711 fish indicated that 69.2 and 26.8% of the fish caught belonged to the 0 + and I + age classes, respectively. While the vast majority of the remaining fish represented the II + age class, a few III + and IV + and one V + fish were also recorded. Growth was seasonal, being greatest in spring and autumn and effectively ceasing in winter. Females began to grow faster than males during their first autumn of life. The respective mean lengths of males and females were 70 and 75 mm at the end of the first year and 90 and 100 mm at the end of the second year. The largest fish caught was a III + female measuring 163 mm and weighing 32.0 g. The respective von Bertalanffy growth curve parameters for L, K and t₀ were 109, 0.758 and - 0.338 for males, and 124, 0.762 and - 0.223 for females. Although the diet of G. occidentalis was always dominated by small terrestrial fauna, and particularly insects, conspicuous seasonal differences were found between the more important of the other components. Data on body size, growth and diet of G. occidentalis are compared with those recorded for other galaxiids.