The eye lens weight and age in the common carp, Cyprinus carpio L.

The validity of the use of the weight of dried eye lenses as an indicator of age in the common carp, Cyprinus carpio L., is tested. There is a significant difference between males and females for fish of two and three years old. Otherwise no significant difference is noted between sexes. The linear relationship between the dry weight of eye lenses and age + 1 are: In Y + 1= 0.5202 + 16.4928 X ( r = 0.93) for female and ln Y + 1=0.4276 + 16.7364 X ( r = 0.94) for male.
The method for determining age is valuable for fish until three years old. However for older fish, in spite of a correlation coefficient between lens weight and age and even with a significant difference between annual groups, the age determination may be misleading due to the overlap in lens weights. In conclusion therefore this method may not be useful for back calculation of growth, for production estimates or studies in which accurate estimates of age are needed.     

Evaluation of the eye lens method for age determination in roe deer<Emphasis Type="Italic">Capreolus capreolus</Emphasis>

Eye lens weight curves were obtained from a sample of 522 male and 171 female free-living roe deerCapreolus capreolus (Linnaeus, 1758), collected during the regular annual harvest 1998/99–2005/06 (May–January) in 12 different field hunting grounds in Vojvodina (North part of Serbia). We found no significant differences in eye lens weight between males and females within the same age class (except age class 1). Thus, the eye lens weight data for both sexes within the same age class were pooled for further analyses. The rate of increase in eye lens weight declined at a relatively early age, but lenses continued to increase in weight through age class 9. However, there was a considerable overlap in ranges of eye lens weights within all age classes, which restricted the usefulness of this method. The estimate precision of the eye lens method in determining age was evaluated by the comparison of “known age” (cementum layer technique) and predicted age (eye lens weight technique). We examined model validity on 78 roe deer not used previously to construct the regression line. The lack of correspondence between the two techniques was evident among individuals within older age classes. The percentage of correctly determined age rapidly declined already from age class 4 (<30%).     

Reduction in below-ground biomass estimates from freezing of soil cores

Study was designed to quantify the effects of freezing soil cores prior to washing on estimates of below-ground biomass. Cores were extracted from nearly pure stands of 3 native grasses growing in a southern USA mixed-grass prairie. Estimates of crown + rhizome biomass in the top 10-cm of the soil profile did not differ as a function of pre-washing treatment (frozenvs unfrozen). However, estimates of root biomass were 26% less from frozen (434 g m^–2) than unfrozen samples (585 g m^–2).     

Effects of dietary deficiency of selective amino acids on the function of the cornea and lens in rats

Summary.  Effects of dietary deficiencies of tryptophan and methionin on the transparency of cornea and lens were investigated in young rats (Brown-Norway, BN; Sprague-Dawley, SD) over 3 months. Transparency of the cornea and lens were evaluated in weekly intervals using a photo-slitlamp microscope. After sacrifice and lens fresh weight determination the lenses were prepared for histopathology. Methionin deficiency had no effect on the parameters investigated. Tryptophan deficiency caused severe loss of body weight in both strains, with additional loss of hair in SD rats. These developed corneal neovascularisations and cataracts. BN rats showed an enhanced zone of discontinuity in the lens. Diet intermission arrested the pathological processes in the eye which restarted when feeding the diet again. This observation is supported by lens fresh weight data. DNA staining evidenced that tryptophan deficiency arrested lens fiber maturation in both strains but stimulated corneal neovascularisation only in SD rats. Received June 29, 2001 Accepted August 6, 2001 Published online July 31, 2002     

Freeze or dehydrate: only two options for the survival of subzero temperatures in the arctic enchytraeid<Emphasis Type="Italic"> Fridericia ratzeli</Emphasis>

Hygrophilic soil animals, like enchytraeids, overwintering in frozen soil are unlikely to base their cold tolerance on supercooling of body fluids. It seems more likely that they will either freeze due to inoculative freezing, or dehydrate and adjust their body fluid melting point to ambient temperature as has been shown for earthworm cocoons and Collembola. In the present study we tested this hypothesis by exposing field-collected adult Fridericia ratzeli from Disko, West Greenland, to freezing temperatures under various moisture regimes. When cooled at –1 °C min^–1 under dry conditions F. ratzeli had a mean temperature of crystallisation (T_c) of –5.8 °C. However, when exposed to temperatures above standard T_c for 22 h, at –4 °C, most individuals (90%, n= 30) remained unfrozen. Slow cooling from –1 °C to –6 °C in vials where the air was in equilibrium with the vapour pressure of ice resulted in freezing in about 65% of the individuals. These individuals maintained a normal body water content of 2.7–3.0 mg mg^–1 dry weight and had body fluid melting points of about –0.5 °C with little or no change due to freezing. About 35% of the individuals dehydrated drastically to below 1.1 mg mg^–1 dry weight at –6 °C, and consequently had lowered their body fluid melting point to ca. –6 °C at this time. Survival was high in both frozen and dehydrated animals at –6 °C, about 60%. Approximately 25% of the animals (both frozen and dehydrated individuals) had elevated glucose concentrations, but the mean glucose concentration was not increased to any great extent in any group due to cold exposure. The desiccating potential of ice was simulated using aqueous NaCl solutions at 0 °C. Water loss and survival in this experiment were in good agreement with results from freezing experiments. The influence of soil moisture on survival and tendency to dehydrate was also evaluated. However, soil moisture ranging between 0.74 g g^–1 and 1.15 g g^–1 dry soil did not result in any significant differences in survival or frequency of dehydrated animals even though the apparent wetness and structure of the soil was clearly different in these moisture contents.Abbreviations DW dry weight - FW fresh weight - MP melting point - RH relative humidity - Tc crystallisation temperatures - WC water contentCommunicated by I.D. Hume     

Effects of live-trapping and toe-clipping on body weight of European and African rodent species

Summary Changes in body weights of four species of small rodents were monitored to evaluate the method of toe-clipping for individual identification. If carefully applied the method was found to be without any biologically meaningful effects on the animals. Secondly, body weight changes in prolonged live-trapping studies were evaluated in five species of small rodents. It was found that the animals generally do not recover from the stress of trapping within 24 h. Absolute weight losses were small on a daily basis but mounted up when animals were trapped day after day.     

Relative influence of unfrozen fraction and salt concentration on the survival of slowly frozen eight-cell mouse embryos

This laboratory has previously reported that the survival of frozen-thawed human erythrocytes is determined more by the fraction of the extracellular solution that remains unfrozen than by the salt concentration in that fraction, especially when the cells are frozen at low hematocrit. To determine the extent to which these findings are applicable to nucleated mammalian cells, we have studied the survival of some 3300 mouse embryos as a function of the unfrozen fraction and the concentration of salt in that unfrozen fraction. Also varied in the study was the weight percentage ratio of glycerol to salt. The concentration of embryos in these experiments (i.e., the cytocrit) was so low that embryo-embryo contacts should have been rare during the freezing. As in the case of the red cells at low hematocrit, we find that the survival of slowly frozen eight-cell embryos is not affected by the high concentrations of salt produced by freezing, at least up to 3.3 molal NaCl, and therefore is not affected by the extent to which the cells shrink below their isotonic volume, nor in general is survival influenced by the temperature at which given salt concentrations and unfrozen fractions are attained or by the glycerol concentration at those temperatures. On the other hand, the attainment of low values of the unfrozen fraction (U) is damaging, but the damage appears in part to be due to the fact that low values of U had to be achieved by placing embryos in solutions hypotonic with respect to NaCl, which caused their volume to be greater than isotonic prior to freezing.     

Studies on Freezing Injury in Plant Cells : II. Protein and Lipid Changes in the Plasma Membranes of Jerusalem Artichoke Tubers during a Lethal Freezing in Vivo

Plasma membranes were isolated from both unfrozen and frozen tissues of Jerusalem artichoke tubers (Helianthus tuberosus L.) in high purity utilizing an aqueous two-polymer phase partition system. Although the recovery of the plasma membranes was decreased significantly by freezing of tissues even at the nonlethal temperature (−5°C), the isolated plasma membrane samples were considered to be representative of the plasma membranes in situ. Freezing of the tissues at sublethal temperatures resulted in marked changes in the chemical composition of the plasma membrane. Those are losses of sterols and phosphatidylethanolamine from the plasma membranes, and a change of specific proteins with relatively high molecular weights into low molecular weight peptides. These specific proteins were designated as frost susceptible proteins. The properties of the plasma membrane ATPase seem to be not affected so much by the in vivo freezing of cells. However, inhibition of the plasma membrane ATPase by N,N′-dicyclohexylcarbodiimide (DCCD) was relatively low before and after freezing in vivo at the nonlethal temperature at −5°C, but was markedly enhanced by freezing in vivo at sublethal temperatures below −10°C. From the results, it is assumed either that the enzyme molecule was partially modified, especially at the presumed DCCD binding sites or that the DCCD had become more accessible to the enzyme as a result of increased permeability of the plasma membranes. These observed changes are discussed in connection with the mechanism of cell injury.     

Accuracy and precision of age determination using growth layer groups for California sea lions (Zalophus californianus) with known ages

Age determination from counts of growth layer groups (GLGs) in tooth dentine is a common method for aging marine mammals. Using known‐aged animals, we validated this method for acid etched teeth of California sea lions (CSLs), Zalophus californianus. Between 1991 and 2013, the upper left canine (n = 33) was collected opportunistically during necropsy from animals tagged or branded as pups that later died. Overall, 55%–61% of age estimates by GLG counting were within 1 yr of the known‐age in the sample of 1–30‐yr‐old CSLs. Accuracy of age estimates was found to be dependent on age of the CSLs, however. 71%–79% of age estimates were within 1 yr of the known‐age in CSLs <10 yr old. These findings support the validity of counting GLGs to estimate age for CSLs <10 yr old to within 1 yr of accuracy.     

Presbyopia and heat: changes associated with aging of the human lens suggest a functional role for the small heat shock protein, alpha-crystallin, in maintaining lens flexibility

Presbyopia, the inability to focus up close, affects everyone by age 50 and is the most common eye condition. It is thought to result from changes to the lens over time making it less flexible. We present evidence that presbyopia may be the result of age-related changes to the proteins of the lens fibre cells. Specifically, we show that there is a progressive decrease in the concentration of the chaperone, α-crystallin, in human lens nuclei with age, as it becomes incorporated into high molecular weight aggregates and insoluble protein. This is accompanied by a large increase in lens stiffness. Stiffness increases even more dramatically after middle age following the disappearance of free soluble α-crystallin from the centre of the lens. These alterations in α-crystallin and aggregated protein in human lenses can be reproduced simply by exposing intact pig lenses to elevated temperatures, for example, 50 °C. In this model system, the same protein changes are also associated with a progressive increase in lens stiffness. These data suggest a functional role for α-crystallin in the human lens acting as a small heat shock protein and helping to maintain lens flexibility. Presbyopia may be the result of a loss of α-crystallin coupled with progressive heat-induced denaturation of structural proteins in the lens during the first five decades of life.     

A Newer Method for Isolation of the 7S Globulin in Soybean Seeds

The effects of freezing on the proteolysis of beef during storage at 4°C after being thawed was investigated.

A sarcoplasmic 32-kDa protein in frozen as well as unfrozen beef decreased rapidly during storage at 4°C, and a more than 100-kDa protein appeared in both beef samples. And the increment of peptides in the frozen beef during the storage at 4°C was larger than that in the unfrozen beef, suggesting that the proteolysis was faster during the storage of the former than the latter. However, its increment in the frozen beef for 10 weeks during the storage at 4°C became smaller than that of the one frozen for less than 5 weeks.

To discover an indicator for evaluation of the conditioning of frozen and unfrozen beef, peptides produced during the storage of beef at 4°C were surveyed. A peptide, APPPPAEVPEVHEEV, was detected and seemed to be available as an indicator in the conditioning of beef.     

Eye lens ageing in the dogfish (Mustelus canis).

1. Age-related alterations in the distribution of water-soluble, high molecular weight (colloidal), and water-insoluble proteins of the lens of smooth dogfish (Mustelus canis) were measured. 2. The ages of these animals ranged approx from 2 to 50 yr, during which time the lenses grew from 100 to 1500 mg (wet wt). The lenses contained approx 50% water. 3. Water-insoluble protein accumulated to a level greater than 50% of the total proteins by the time the animals reached maturity. The lenses of other animals, such as mammals and humans, would be opaque if they had a similar insoluble protein content. 4. Each protein fraction contained the same protein chains (mol. et 1900-25,000 daltons), as observed by SDS polyacrylamide gel electrophoresis, except the water-insoluble fraction, which seemed to contain several extra protein chains with higher molecular weights, which represent fiber cell membrane components. 5. Further purification of these fiber cell membranes indicated that their protein chain makeup was mainly from the same low molecular weight chains present in the soluble and high molecular weight colloidal proteins.     

The process of freezing and the mechanism of damage during hepatic cryosurgery

Experiments were performed to correlate the structures of liver tissue frozen during cryosurgery, liver frozen at various constant cooling rates, and unfrozen, dried normal liver. The results show that during freezing of tissue ice forms and propagates along the vascular system, expanding during freezing at low cooling rates. This expansion occurs over most of the region frozen during cryosurgery and may be one of the mechanisms of damage to tissue during cryosurgery.     

Sturgeons,sharks, and rays have multifocal crystalline lenses and similar lens suspension apparatuses

Crystalline lenses with multiple focal lengths in monochromatic light (multifocal lenses) are present in many vertebrate groups. These lenses compensate for chromatic aberration and create well‐focused color images. Stabilization of the lens within the eye and the ability to adjust focus are further requirements for vision in high detail. We investigated the occurrence of multifocal lenses by photorefractometry and lens suspension structures by light and electron microscopy in sturgeons (Acipenseriformes, Chondrostei) as well as sharks and rays (Elasmobranchii, Chondrichthyes). Multifocal lenses were found in two more major vertebrate groups, the Chondrostei represented by Acipenseriformes and Chondrichthyes represented by Elasmobranchii. The lens suspension structures of sturgeons, sharks, and rays are more complex than described previously. The lens is suspended by many delicate suspensory fibers in association with a ventral papilla in all groups studied. The arrangements of the suspensory fibers are most similar between sturgeons and sharks. In rays, the lens is suspended by a smaller ventral papilla and the suspensory fibers are arranged more concentrically to the lens. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.     

Crystallin distribution patterns in Litoria infrafrenata and Phyllomedusa sauvagei lenses

The eye lens remains transparent because of soluble lens proteins known as crystallins. For years γ-crystallins have been known as the main lens proteins in lower vertebrates such as fish and amphibians. The unique growth features of the lens render it an ideal structure to study ageing; few studies have examined such changes in anuran lenses. This study aimed to investigate protein distribution patterns in Litoria infrafrenata and Phyllomedusa sauvagei species. Lenses were fractionated into concentric layers by controlled dissolution. Water-soluble proteins were separated into high (HMW), middle (MMW) and low molecular weight (LMW) fractions by size-exclusion HPLC and constituents of each protein class revealed by 1DE and 2DE. Spots were selected from 2DE gels on the basis of known ranges of subunit molecular weights and pH ranges and were identified by MALDI-TOF/TOF MS following trypsin digestion. Comparable lens distribution patterns were found for each species studied. Common crystallins were detected in both species; the most prominent of these was γ-crystallin. Towards the lens centre, there was a decrease in α- and β-crystallin proportions and an increase in γ-crystallins. Subunits representing taxon-specific crystallins demonstrating strong sequence homology with ζ-crystallin/quinone oxidoreductase were found in both L. infrafrenata and P. sauvagei lenses. Further work is needed to determine which amphibians have taxon-specific crystallins, their evolutionary origins, and their function.     

Overexpression of the vimentin gene in transgenic mice inhibits normal lens cell differentiation

To investigate the role of the intermediate filament protein vimentin in the normal differentiation and morphogenesis of the eye lens fiber cells, we generated transgenic mice bearing multiple copies of the chicken vimentin gene. In most cases, the vimentin transgene was overexpressed in the lenses of these animals, reaching up to 10 times the endogenous levels. This high expression of vimentin interfered very strongly with the normal differentiation of the lens fibers. The normal fiber cell denucleation and elongation processes were impaired and the animals developed pronounced cataracts, followed by extensive lens degeneration. The age of appearance and extent of these abnormalities in the different transgenic lines were directly related to the vimentin level. Electron microscopic analysis revealed that the accumulated transgenic protein forms normal intermediate filaments.     

Photon correlation spectroscopy of light scattered by eye lenses in in vivo conditions.

The application of photon correlation spectroscopy on mammalian eye lenses in vivo is revisited. It is shown that the use of a short wavelength laser type and a logarithmic correlator improves the signal-to-noise ratio to such an extent that shorter measurement times are possible without impairing the information content of the correlation function. Experimental correlation functions obtained in vivo on a rabbit eye lens, are analyzed with several techniques. The histogram approach is most successful for the determination of the distribution function of relaxation processes in the correlation function and proposes four different populations of components in the lens. This result is comparable to that from in vitro measurements on highly concentrated solutions of alpha-crystallins and of fiber cell cytoplasm, the former proteins being the main scattering components both in vivo and in vitro in the eye lens system. Our results indicate that the application of photon correlation spectroscopy on eye lenses in vivo offers new perspectives to use this technique as a fast, noninvasive tool to study relaxation phenomena in normal and cataractous lenses. The sensitivity of the method allows it to be used as an important analytical technique in the study of prevention and treatment of cataract.     

Cryobanking as tool for conservation of biodiversity: effect of brown trout sperm cryopreservation on the male genetic potential

Sperm cryobanking could be a good alternative to breeding in captivity in order to preserve genetic diversity. Sperm from two well-characterized brown trout populations originating from two river basins in the Northwest of Spain (Esla and Duerna), both threatened by extinction, was cryopreserved. In order to determine whether a sperm cryobank is the best option for preserving genetic profiles, cell viability, chromatin fragmentation, fertility and genetic variability of the offspring obtained with fresh and frozen sperm, were analyzed. Sperm viability was not reduced by freezing (87.0 ± 3.32% to 77.9 ± 3.59% and 77.6 ± 6.53% to 76.6 ± 2.61% in fresh and frozen sperm from Esla and Duerna, respectively). The percentage of fragmented DNA increased after freezing in spermatozoa from Esla males (from 4.7 ± 0.23% to 6.0 ± 0.28%), but not those from Duerna males.After freezing/thawing, the percentage of eyed embryos drops from 66.8 ± 6.77% to 16.1 ± 3.46% and from 50 ± 8.97% to 11.5 ± 2.50% in the Esla and Duerna basins, respectively. This reduction indicates that many spermatozoa have lost their ability to contribute to embryo development and this loss is not related to either spermatozoa viability or the DNA integrity. Genotypic determination by microsatellite analysis showed that frozen/thawed sperm provided offspring with a similar genetic profile to unfrozen milt, demonstrating the accuracy of the cryopreservation procedure.Taking into account the prolificacy of this species, even a low rate of success of fry after cryopreservation, could provide enough individuals to recover stable populations without altering the genetic profiles of the preserved strains. Therefore, cryopreservation is considered a safe, simple and cheap technology for gene banking in the analyzed brown trout populations.     

Aberrations of chick eyes during normal growth and lens induction of myopia

Understanding the control of eye growth may lead to the prevention of nearsightedness (myopia). Chicks develop refractive errors in response to defocusing lenses by changing the rate of eye elongation. Changes in optical image quality and the optical signal in lens compensation are not understood. Monochromatic ocular aberrations were measured in 16 chicks that unilaterally developed myopia in response to unilateral goggles with −15D lenses and in 6 chicks developing naturally. There is no significant difference in higher-order root mean square aberrations (RMSA) between control eyes of the goggled birds and eyes of naturally developing chicks. Higher-order RMSA for a constant pupil size exponentially decreases in the chick eye with age more slowly than defocus. In the presence of a defocusing lens, the exponential decrease begins after day 2. In goggled eyes, asymmetric aberrations initially increase significantly, followed by an exponential decrease. Higher-order RMSA is significantly higher in goggled eyes than in controls. Equivalent blur, a new measure of image quality that accounts for increasing pupil size with age, exponentially decreases with age. In goggled eyes, this decrease also occurs after day 2. The fine optical structure, reflected in higher-order aberrations, may be important in understanding normal development and the development of myopia.     

Reconstruction of the shape and optics of the lenses in the abathochroal‐eyed trilobite Neocobboldia chinlinica

Until now, the structure and optics of the calcite lenses in abathochroal trilobite eyes have not been investigated. So, the relationship of the abathochroal eye to other types of trilobite eyes has remained unclear. We have reconstructed the exact shape and optics of the lenses in the eodiscid trilobite Neocobboldia chinlinica to determine the mechanism of its abathochroal eye. The distal lens surface has a convex profile, while on the proximal lens surface there is a small central bulge, resulting in an undulating profile. Due to this bulge, the curvature and refractive power of the central region of the lens are greater than those of the peripheral zone. Consequently, the lens is bifocal. However, Neocobboldia could not take advantage of this bifocal property of its tiny lenses because of the diffraction of light and the infinite depth of field in object space. For the same reason, it is also sure that the undulating lower surface of the abathochroal lens did not evolve as a Huygensian profile, correcting for spherical aberration, as suggested earlier. This undulation is a result of the presence of the central bulge, the evolutionary significance of which remains enigmatic. On the basis of our results, we have outlined an evolutionary scenario for development of the optics of the lenses in trilobite eyes.