Externally visible fluorochrome marks and allometries of growing sea urchins

Externally visible, growing calcitic structures can be marked using fluorochromes. Such marks are useful for field recapture studies in ecology, evolution, and aquaculture as well as for studies on mechanisms of growth and development. We marked 2‐month‐old sea urchins (Strongylocentrotus droebachiensis) with the fluorochromes calcein, calcein blue, and tetracycline by batch‐marking via immersion. Neither growth nor survival was affected by marking. Marks were externally visible on the skeletal plates, demipyramids, and spines of 100% of the marked sea urchins up to 63 d post‐marking. After 342 d, marks were still externally visible on 100% of calcein‐marked, 98% of calcein blue‐marked, and 22% of tetracycline‐marked sea urchins. Marks were brightest on calcein‐marked and faintest on tetracycline‐marked sea urchins, in correspondence to the fluorochrome dose. Growth marks in the aboral oculogenital ring, followed for 333 d, showed that genital plate growth in the hoop direction was greatest adjacent to the anal suture and that both the oculogenital ring and periproct grew less than isometrically. Internal marks (not externally visible) were subsequently seen on 99% of the demipyramids at 342 d post‐marking. Such fluorochrome marks on demipyramids have previously been used to measure aboral and oral‐end demipyramid growth to allometrically calibrate diametrical growth rates of field sea urchins. We found that although aboral demipyramid marks were always clear, 13% of marks on the oral end were obscured. However, we show that measuring only aboral end growth is sufficient for allometric calibration. In a separate experiment, multiple marks of the above three fluorochromes plus alizarin complexone, administered by injection to larger (12.9–37.1 mm diameter) sea urchins, persisted internally for at least 2 years. Multi‐color, internally and externally visible, persistent marks will enhance experimental designs in laboratory, field, and common garden experiments.     

Mass marking of Leuciscus idus larvae using Artemia salina as a vector of fluorescent dyes

A method for the mass marking of ide Leuciscus idus larvae by feeding them Artemia salina nauplii that were immersed in different solutions of alizarin red S, tetracycline hydrochloride and calcein was tested. The best quality marks were obtained after feeding fish for 4 days with nauplii that had been immersed in 200 mg l^?1 alizarin red S.     

A new fluorescence method for alkaline phosphatase histochemistry.

We have developed a new fluorescence method for the histochemical localization of alkaline phosphatase activity. Calcium phosphate deposited at the sites of alkaline phosphatase activity in a Gomori-type reaction are identified by calcium binding fluorochromes. The calcium binding fluorochromes calcein, calcein blue, and xylenol orange were investigated, with each fluorochrome being included in the alkaline phosphatase incubating medium and used in a single-step procedure. Alkaline phosphatase activity was studied in freeze-substituted, resin-embedded human liver and jejunal biopsies, and each fluorochrome produced intense fluorescence of different colors at sites of alkaline phosphatase activity. Calcein, calcein blue, and xylenol orange produced green, blue, and red fluorescence, respectively. Sites of enzyme activity were accurately localized without evidence of diffusion, and there was an absence of non-enzyme-catalyzed binding of any of the fluorochromes to tissue. This fluorescence method, which is particularly suited to investigating the localization and distribution of the activity of different enzymes in the same section, was used to investigate the distribution and co-localization of alkaline phosphatase and aminopeptidase M in human liver and jejunum.     

Growth and energy allocation in the deep-sea urchin Echinus affinis

Growth of regular echinoids, expressed as test diameter through time, generally shows a sigmoidal pattern. However, when urchin size is considered in terms of test volume we show that growth of the deep-sea echinoid Echinus affinis is ultimately linear, rather than saturating. We construct a simple allometric model of energy allocation that produces linear growth in volume in mature urchins by allocating an increasing proportion of net assimilate to reproduction. This model provides an excellent fit to the observed growth curve data. Data on gonad weight as a function of test diameter allow us to test the relationship between allocation to reproduction and urchin size predicted from the growth curve fit. Simultaneous fitting of the growth curve and gonad weight data allow us to consider a model where the allometry of net assimilation is allowed to vary. We investigate possible explanations for the fact that net assimilation appears to rise faster than linearly with weight in E. affinis. We conclude that strategic models of individual energetics provide a useful tool for the analysis of the limited data available on deep-sea populations.     

Gonad growth in the sea urchin, Strongylocentrotus purpuratus (Stimpson) (echinodermata: Echinoidea) and the assumptions of gonad index methods

In central Oregon intertidal populations, the echinoid Strongylocentrotus purpuratus (Stimpson) first begins to produce mature gametes at a diameter of 25 mm during the second year of its life. All individuals above 40 mm in diameter have mature gametes during the mid-winter spawning season. Gonad size increases rapidly relative to body size until the animals are ≈45 mm in diameter and have a total dry weight of ≈ 15 g. The ratio of gonad to body size reaches its maximum in animals between 40 mm and 50 mm in diameter; thereafter the ratio drops slightly with increasing size. The curvilinear relation between gonad size and body size is not related to a relative difference in body proportions with size. Internal volume, height, and diameter increase linearly with size. Body proportions did not differ between the two populations studied. Differences between populations in the ratio of gonad to body size extend to all sizes in the populations and the direction but not the amount of the difference is consistent from year to year. These differences between habitats are probably related to food supply. The use of gonad ratio methods to normalize gonad size assumes that, within a given population, animals of different body size have the same ratio of gonad size to body size. This assumption is not correct for four species of sea urchins. Gonad index or ratio methods are useful for comparing animals of the same size through time within a population or from different habitats. Restriction of the size range of animals used and use of samples of sufficient size permit gonad ratios to be used to assess the capacity of different habitats to support gonad production in sea urchins and other animals.     

遮蔽行为对海刺猬摄食、生长和性腺性状的影响

海胆遮蔽行为对于海胆的生长和发育的影响目前还不清楚,在实验室条件下,研究了遮蔽行为对海刺猬(Glyptocidariscrenularis)摄食、生长和性腺性状的影响。实验设两个对照组和一个处理组:对照组为无任何遮蔽条件的空白组和以堆积砖块创造的黑暗空间来满足海胆的掩蔽行为的掩蔽组,遮蔽组则以菲律宾蛤仔(Ruditapes philippinarum)的贝壳作为遮蔽物来满足海胆的遮蔽行为。结果显示:遮蔽组的海胆周摄食量要显著大于掩蔽组(P<0.05),而空白组与遮蔽组和掩蔽组之间的差异不显著(P>0.05);各组海胆的存活率没有显著差异(P>0.05);空白组和遮蔽组海胆的壳径、壳高、体重要显著大于掩蔽组(P<0.05),而空白组和遮蔽组之间没有显著性的差异(P>0.05);空白组和遮蔽组的性腺湿重、性腺干重、性腺指数、壳湿重、壳干重、亚氏提灯湿重、亚氏提灯干重要显著大于掩蔽组(P<0.05),而空白组和遮蔽组之间没有显著性的差异(P>0.05);空白组的提灯指数要显著小于遮蔽组和掩蔽组(P<0.05),而遮蔽组和掩蔽组之间没有显著的差异(P>0.05)。结果证明,遮蔽和掩蔽行为对海刺猬生长及发育的影响是有差别的,掩蔽行为对海刺猬的生长与发育造成了负面影响,而遮蔽行为在一定的生活环境条件下不会对其生长造成影响。研究表明,海刺猬的遮蔽行为反映了其对外界不利环境条件的一种适应性,且这种行为对其生长和发育的影响与掩蔽行为有所不同。至于海刺猬遮蔽行为的进化选择压力,目前的研究还不足以下定论,需要进一步深入的研究。     

The use of live and frozen Artemia salina nauplii enriched with fluorochromes for mass‐marking vendace Coregonus albula (L.) larvae

The aim of this study was to investigate the use of Artemia salina nauplii enriched with chosen fluorochromes for mass marking vendace Coregonus albula (L.) larvae. In the experiment, vendace larvae (6 DPH) were fed with live or frozen A. salina nauplii immersed in tetracycline hydrochloride (TC), calcein (Cal) or alizarin red S (ARS) for four subsequent days. More successful effects (marking otoliths) were obtained by feeding the fish with live nauplii enriched with fluorochromes, regardless of the dye type. The highest percentage of marked otoliths (100%) was recorded in the group fed with live nauplii immersed in TC. In the groups fed live or frozen nauplii enriched with Cal and ARS, a lower percentage of marked individuals (63.3%–73.7% and 56.7%–63.3%, respectively) were recorded. The survival rate of vendace larvae in particular groups oscillated between 93.7% and 95.7%. There were no significant differences in the total body length and body weight of the reared vendace larvae among different groups. In conclusion, for mass marking of vendace larvae using a feeding method, fish fed A. salinalive nauplii enriched with TC at a dose of 600 ppm is recommended for fishery practice.     

Select light spectra affect gonad color in the sea urchin Lytechinus variegatus

It is suggested that gonad color in sea urchins depends upon the in vivo accumulation and metabolism of red and yellow carotenoid pigments. We hypothesized that differential light exposure could affect carotenoid deposition and, hence, gonad color in sea urchins. We therefore performed two experiments to determine whether light spectra affect the gonad color of Lytechinus variegatus. In the first experiment, urchins were fed a formulated feed supplemented with or without β-carotene and held beneath three lighting regimes designed to emit differing wavelengths of the visible spectrum. After 12 weeks, urchins were dissected and gonad color (CIE L*a*b*) was measured with a Pantone Capsure RM200. Actinic light significantly increased the value of a* (red) in gonad color. Color in the orange and yellow spectra in the gonads increased in individuals fed the β-carotene supplemented diet. In the second experiment, we cultured urchins for nine weeks under lamps specialized to emit UV radiation. All urchins in this experiment received diets supplemented with β-carotene. There was no significant difference in harvested gonad color between these treatments. These data suggest that light quality and dietary carotenoids affect carotenoid deposition in the gonads.     

The commercial potential of the common sea urchin Echinus esculentus from the west coast of Scotland

Sea urchin roe is a valuable food product. The commercial potential of Echinus esculentusL. (Echinodermata: Echinoidea) was assessed both by surveying field populations and gonad growth in response to artificial feeds. Urchins were collected from four locations on the Scottish west coast between June and August of 1998. The roe content was found to be of variable quality. A relatively low percentage of urchins (34.9%) had roe which was considered marketable both in terms of yield and colour. Urchins with a marketable yield of roe were found where algal growth or encrusting organisms were most prolific. Good roe colours and high roe yields were not necessarily coincident. The data suggest an urchin fishery is likely to be impractical economically. In tank-based trials large E. esculentus were fed either commercially available salmon feed, a pelletised urchin diet or the macroalgae Laminaria saccharina. Urchins fed the artificial diets increased in test diameter during the 24-week experiment. At the end of the trial urchins fed salmon feed had a significantly higher gonad and alimentary index than those in the other treatments. E. esculentusis able to successfully exploit a diet rich in animal-origin oils. The diets also influenced gonad colour. The proportion of urchins with marketable gonad colours was highest (85%) in the treatment receiving salmon feed. As this species appears robust in culture and as artificial diets promote somatic and gonadal growth, an investigation into the practicalities of a fully farmed approach to gonad production may be worthwhile.     

Long-Term Changes in the Gonad Condition of the Sea Urchin Strongylocentrotus intermediusfrom Alekseev Bight (Amurskii Bay) under Polluted Conditions

The gonad condition of the sea urchin Strongylocentrotus intermediuscollected in August 1997 at two stations in Peter the Great Bay was examined. One of the stations was located in a polluted area (Alekseev Bight, Popov Island) and the other, in a relatively clean area (the Verkhovskii Islands). The results were compared with analogous data for 1984, 1985, and 1989. In 1997, the gonad condition of sea urchins inhabiting the two areas differed significantly. The mean value of the gonad index (GI) for sea urchins from Alekseev Bight was less than half and the maturity index was about twice that of sea urchins from the Verkhovskii Islands. The GI of sea urchins from Alekseev Bight decreased by a factor of 1.5 between 1984 and 1997. Pronounced histopathological changes were found in sea urchin gonads at this station: granular and hydropic dystrophy of oocytes, resorption and a sharp decrease in the number of gametes (in about 20% of the sea urchins, hardly any gametes were found in the gonads), changes in the morphology of accessory cells (hypertrophy, atrophy, and necrosis), and accumulation of lipofuscin in the cytoplasm of accessory cells and oocytes, in the hemal sinuses and mesentery. The suppressed gonad condition of the sea urchin S. intermediusin Alekseev Bight may be a consequence of the unfavorable environmental situation that formed in the bight in the 1980s–1990s. The main negative factor is anthropogenic pollution of Amurskii Bay.     

The effect of temperature on feeding and growth characteristics of the sea urchin Lytechinus variegatus fed a formulated feed

We investigated the effect of culture temperature on feed intake, absorption, organismal growth, and tissue production of Lytechinus variegatus by culturing individuals at three different temperatures representing the normal range of temperature exposure in wild populations in the northern Gulf of Mexico. Large L. variegatus (ca. 42 + 0.6 mm diameter, 36 + 1.3 g wet weight, n = 97) were collected at St. Joseph Bay, Florida, in October 2001. Eight sea urchins were held individually in 1-L containers within an 80-L aquarium with recirculated synthetic seawater at 32-ppt salinity. Three aquaria with the containers were each placed in three incubators at temperatures of 16, 22, or 28 °C for 8 weeks. Sea urchins held at 22 °C had the highest rate of feed intake. Feed intake in individuals held at 16 °C decreased significantly during the first 2 weeks of exposure and then increased to values not significantly different from those held at 28 °C by week 6. The dry matter absorption efficiency of individuals held at 28 °C was significantly higher than those held at 16 °C or 22 °C. The percentage of organic matter in the feces did not vary significantly with temperature. Individuals increased significantly in diameter, wet weight, and gonad weight at all temperatures. The wet weights of individuals held at 22 °C were significantly higher than those held at 28 °C or 16 °C, which did not differ significantly. The gut weight varied inversely with temperature. The wet weight of gonads of individuals held at 22 °C was significantly higher than those held at 28 °C, but neither differed significantly from those held at 16 °C. Production efficiencies, both organismal and gonadal, were inversely proportional to temperature, indicating that the overall metabolic cost of production increased with increasing temperatures. Organism production efficiencies were lower and gonad production efficiencies were higher than those found in small sea urchins, emphasizing that patterns of nutrient allocation vary between small and large sea urchins. Physiological processes associated with feed intake, absorption, and nutrient allocations vary with temperature, but allow the sea urchins to maintain growth and gonad production at a variety of temperatures. These data suggest that temperatures near the upper limits do not promote efficient use of resources, an important consideration for future commercial culture. Since gonad (roe) production is the ultimate goal of many aquaculture operations, gonad production efficiencies will provide a valuable tool for evaluating the efficacy of various feeds and feeding conditions on gonad production.     

Natural growth lines in echinoid ossicles are not reliable indicators of age: a test using Strongylocentrotus droebachiensis

Abstract. Natural growth lines in the ossicles of echinoids have been used to estimate age, calculate growth curves, and infer population age-structure. However, few studies evaluate whether these bands are added annually–a critical assumption of the aging technique. We tested whether the banding pattern is annual in Strongylocentrotus droebachiensis. Sea urchins were tagged with a fluorescent marker, released into tidepools, and collected 1 year later. We quantified the position of the fluorescent mark relative to subsequent growth bands. In 30 individuals ranging in test diameter from 14 to 77 mm, and in a series of ∼2 mm size intervals, we examined 3 interambulacral plates (aboral, ambital, and oral) and a rotula from Aristotle's lantern. Overall, only 7 sea urchins (23%) added a complete band to all 4 ossicles. In 6 sea urchins (20%) at least 1 ossicle added more than 1 complete band. In many sea urchins, especially those >55 mm in diameter, most ossicles added less than 1 band. The banding pattern in ossicles seriously underestimates age in S. droebachiensis and population parameters inferred from these growth lines are biased. Before using the growth-band aging method in other echinoids, it must be demonstrated that 1 band is added annually for all sizes in a population under field conditions.     

Experimental evaluation of using calcein and alizarin red S for immersion marking of bighead carp Aristichthys nobilis (Richardson, 1845) to assess growth and identification of marks in otoliths,scales and fin rays

In order to evaluate the effects of immersion marking with calcein (CAL) and alizarin red S (ARS) on growth and mortality of juvenile bighead carp Aristichthys nobilis, and assess mark quality in otoliths, scales, and fin rays, CAL from 50 to 200 mg L^?1 and ARS from 150 to 300 mg L^?1 concentrations were used. With the exception of non‐lateral line scales from 50 mg L^?1 CAL treatments, immersion for 24 h produced detectable marks in sagittae, lateral line and non‐lateral line scales, and fin rays (dorsal, pectoral, ventral, anal, and caudal) at 100 days post‐marking. Detectable fluorescent marks in sagittae were readily observed at concentrations of 150–200 mg L^?1 CAL or 150–300 mg L^?1 ARS. Marks were poorly visible in all non‐lateral line scales from both CAL‐ and ARS‐treated groups. Fluorescent marks were readily detected in lateral line scales at 100–200 mg L^?1 CAL or 150–300 mg L^?1 ARS, and in fin rays at 150–200 mg L^?1 CAL or 150–300 mg L^?1 ARS. In particular, optimal marks were observed at the highest concentrations investigated in sagittae (300 mg L^?1 ARS), lateral line scales (150–200 mg L^?1 CAL or 250–300 mg L^?1 ARS), and fin rays (200 mg L^?1 CAL or 250–300 mg L^?1 ARS). However, fluorescent marks visible to the naked eye were not produced by any of the CAL or ARS treatments in sagittae, scales, or fin rays during this experiment. In addition, there was no significant difference on survival and growth of marked fish compared to controls throughout the experiment (P > 0.05).     

Habitat-dependent growth in a Caribbean sea urchin <Emphasis Type="Italic">Tripneustes ventricosus</Emphasis>: the importance of food type

The sea urchin Tripneustes ventricosus is a common, yet relatively poorly known, grazer of seagrass beds and coral reefs throughout the Caribbean. We compared the size and abundance of urchins between adjacent seagrass and coral reef habitats (where macroalgae are the dominant primary producers). We also conducted a laboratory experiment comparing the growth rate of juvenile urchins fed a diet of either macroalgae or seagrass. Reef urchins had significantly larger test diameter than those in the seagrass on some sampling dates. This size difference may be at least partially explained by diet, because laboratory-reared urchins fed macroalgae grew significantly faster than those fed seagrass. The seagrass population, however, was stable over time, whereas the reef population exhibited strong fluctuations in abundance. Overall, our study indicates that both the seagrass and coral reef habitats are capable of supporting healthy, reproductive populations of T. ventricosus. Each, however, appears to offer a distinct advantage: faster growth on the reef and greater population stability in the seagrass.     

Effect of macrophyte diet and initial size on the survival and somatic growth of sub-adult <Emphasis Type="Italic">Strongylocentrotus purpuratus</Emphasis>: a laboratory experimental approach

Recently recruited urchins from the same brood, but with different initial sizes, may respond differently to similar environmental factors. The aim of this study was to assess and compare the effects of starvation and diet on the survival, growth rates in size and weight, and gonad index among small and large sub-adult purple sea urchins, Strongylocentrotus purpuratus. Small urchins ranged from 7.3 to 7.8 mm and large urchins from 11.8 to 14.1 mm (test diameters). Two independent experiments were performed. In the first experiment, sea urchins were fed during 22 weeks on Egregia menziesii (ad libitum) and for only 1 day month⁻¹ (starved condition). Feeding regime significantly affected survival, somatic growth rate in size and weight, and gonad index, with higher means in the ad libitum treatments than in starving conditions. A recurrent cannibalism event by conspecifics occurred in small sea urchins under starving conditions. In the second experiment, sea urchins were fed during 13 weeks ad libitum with four diets: kelp (E. menziesii), coralline algae (Bossiella orbigniana), eelgrass (Phyllospadix scouleri) and a mixed diet of the three species. Survival was not affected by diet or urchin size, but diet significantly affected somatic growth rate in size and weight and gonad index. Kelp promoted the highest growth rate (2.23 ± 0.21 mm month⁻¹), the mixed diet produced an intermediate growth (1.26 ± 0.21 mm month⁻¹), while the lowest values corresponded to coralline algae and the eelgrass (0.30 ± 0.12 and 0.10 ± 0.03 mm month⁻¹, respectively, means ± SE). The mean growth rate of small urchins (averaging all diets) was higher than in large specimens (1.17 ± 0.37 and 0.77 ± 0.28 mm month⁻¹, respectively).     

Batch marking of otoliths and fin spines to assess the stock enhancement of Argyrosomus japonicus

Juvenile mulloway Argyrosomus japonicus (54·6 ± 4·6 mm total length, mean ±  s . e .) were immersed in a range of oxytetracycline (OTC) solutions ranging between 0–600 mg l⁻¹ in salinities of 5 (diluted sea water) and 35 (undiluted sea water), and alizarin complexone (ALC) solutions ranging between 0–60 mg l⁻¹ in undiluted sea water, for 6, 12 and 24 h. Optimal marking conditions were 600 mg l⁻¹ OTC for 24 h in a salinity of 5, and 30 mg l⁻¹ ALC for 12 h respectively. Mark quality (MQ) was assessed using a score of 0–3 in both otoliths and anal fin spines, with a score >2 found to be acceptable for adequate mark identification. Acceptable marks were not produced using OTC in undiluted sea water. Immersion in OTC or ALC, or reduced salinity had no effect on survival relative to controls. Transverse sections of vertebrae from the ALC and OTC treatments with the highest otolith mark quality showed no discrete marks. Optimal marking techniques were used to produce double marks with a 3 day interval between marking, and marking techniques were applied to 130 000 juvenile mulloway in batch mode with minimal mortality. A numerical model of the chemical behaviour of OTC in sea water describes the decline of available OTC in increasing salinity, so that a species' salinity tolerance and successful marking can be optimized.     

The effect of dietary protein and carbohydrate concentration on the biochemical composition and gametogenic condition of the sea urchin Lytechinus variegatus

Previously starved urchins, Lytechinus variegatus, (36.0 ± 0.8 (SE) mm test diameter) were held in replicated (3) 10-L aquaria with artificial seawater at 22 ± 2  °C and 32‰ salinity and fed three diet treatments. Urchins were fed diets containing 9 : 35, 20 : 23 or 31 : 12% dry protein: % dry carbohydrate (P : C) ad libitum for a 65-day period. Gonads from urchins fed the 9 : 35 P : C diet had similar organic, lower ash, and lower water content than urchins fed the 31 : 12 P : C protein diet. Water content varied with both diet and nutritional history; consequently, water content may have limited value as a predictor of gonad nutritional status. Protein and carbohydrate concentrations in the gonad were directly related to the dietary composition of these nutrients; gonad lipids did not vary with diet. Excess carbohydrates are frequently stored as fats in fish and mammals but this does not appear to be the case in L. variegatus. Test carbohydrate storage and gut protein storage also reflected dietary composition. Image analysis of ovaries indicated decreased nutritive phagocyte volume, increased germinal epithelium volume and larger oocyte diameters in urchins fed high protein, low carbohydrate diets. Analysis of testes also indicated decreased nutritive phagocyte volume and increased gamete volume with urchins fed high protein, low carbohydrate diets, but differences among treatments were less obvious than in ovaries. This study suggests that high protein, low carbohydrate diets promote gamete growth and development. In addition, the biochemical and gametic composition of gonads can be altered by manipulating dietary composition. This could affect the quality and value of sea urchin roe for human consumption.     

Identification of protein components from the mature ovary of the sea urchin Evechinus chloroticus (Echinodermata: Echinoidea)

The gonads of sea urchins are a high value seafood product, with considerable research being undertaken worldwide on the development of sea urchin aquaculture. As the best prices are obtained for specific gonad attributes, research has also focused on the development of artificial diets that enhance gonad quality and quantity. Total protein has been used as a measure of gonad quality; yet no studies to date have applied proteomics technology to diet development. Here we use a MudPIT and 2-DE approach to describe the major proteins in mature ovaries of a New Zealand sea urchin Evechinus chloroticus. This tissue, which is a target seafood product, contained 138 proteins that were identified from the recently completed sea urchin genome (Strongylocentrotus purpuratus) with high confidence. The majority of these proteins had general functions, with only 12 related to ovarian reproductive function. Eighteen proteins were located on the 2-DE; four of these were directly identified from S. purpuratus protein sequences. In combination this paper shows that the genome resources of S. purpuratus can be used to identify proteins in sea urchins from different families; describes the proteome of E. chloroticus mature ovary; and, provides proteomic tools for analysis of gonads from other edible sea urchins.     

流速对光棘球海胆行为和生长的影响

海胆在海藻床生态系统结构和功能调控中发挥重要作用。深入理解流速对海胆摄食和生长的影响具有重要的生态学研究价值。研究了长时间(49 d)不同流速(2 cm/s, 10 cm/s和20 cm/s)对光棘球海胆幼胆(Mesocentrotus nudus,壳径：约20 mm)摄食行为、摄食量和生长的影响,以评估不同流速下,海胆摄食行为和生长的差异。实验结果表明,流速对光棘球海胆的存活无显著影响,但显著影响其生长。2 cm/s下海胆的壳径和体重显著大于10和20 cm/s。在实验开始后的第2周和第3周,2 cm/s下海胆的体重和壳径已显著高于20 cm/s。流速显著影响光棘球海胆的摄食量(P<0.001)和觅食行为(20 cm/s,P=0.004),但口器咬合行为未受显著影响(P=0.113)。管足附着时间在流速为10 cm/s和20 cm/s下显著长于其在2 cm/s。同样的,相较于2 cm/s(P=0.02)和10 cm/s(P=0.03),20 cm/s的流速可显著削弱光棘球海胆的翻正行为。综上,高流速(20 cm/s)通过影响海胆管足活动削弱其觅食行为(而非摄食行为),进而降低其...     

Monocyte function is severely impaired by the fluorochrome calcein acetomethylester

For rapid chemotaxis quantification, cell prelabelling is often performed with the fluorochrome calcein acetomethylester (calcein AM). We investigated whether calcein AM-prelabelling is reliable for monocyte migration analysis. Human monocytes were either preexposed to calcein AM or unlabelled. Monocyte migration towards the potent chemoattractants transforming growth factor-beta1 (TGF-beta1) and N-formyl-Methionin-Leucin-Phenylalanin (fMLP) was assessed using a 48-well micro-chemotaxis chamber. For quantification, cells were visualized by light microscopy and counted. Surprisingly, random migration of calcein AM-prelabelled cells was significantly impaired compared to the unlabelled control. Accordingly, monocyte chemotaxis towards either TGF-beta1 or fMLP dramatically declined. Adherence of calcein AM-labelled monocytes on plastic was also significantly decreased compared to control cells. As adhesion is regarded as an essential component of monocyte migration, the reduced migration observed in calcein AM-labelled monocytes might be explained by a fluorochrome-induced adhesion defect. Therefore, use of the fluorochrome calcein AM cannot be recommended for functional testing of monocytes.