A biochemical index of duration of the molt cycle for planktonic Crustacea based on the chitin‐degrading enzyme, chitobiase

Espie, Patrick J.; Roff, John C.

doi:10.4319/lo.1995.40.6.1028

Cited by 34 publications

(16 citation statements)

References 14 publications

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“…Alternatively, it may be a PRS-type response to temperature near the lower limit physiologically tolerable by Calanus pacificus (Anger 2001). Non-linear changes in the proportion of a developmental stage spent in premolt, in which premolt duration deviates from a constant proportion of stage duration only at extreme temperatures, have also been inferred for Daphnia magna (Espie & Roff 1995). Further work will be required to clarify the relationship between molt-phase duration and temperature.…”

Section: Discussionmentioning

confidence: 90%

Ecdysteroids in the oceanic copepod Calanus pacificus: variation during molt cycle and change associated with diapause

Johnson¹

2003

Mar. Ecol. Prog. Ser.

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Development through the molt cycle in arthropods is characterized both by changes in exoskeleton morphology and by cyclical changes in ecdysteroids, i.e. molting hormones. This study describes for Calanus pacificus ecdysteroid variation during the molt cycle in the fifth copepodid (CV) stage and compares ecdysteroid content of diapausing and active field-collected CVs. In C. pacificus CVs, the pattern of ecdysteroid variation relative to the molt cycle phase is similar to that found in decapod crustacean larvae. Ecdysteroid levels are lowest in the postmolt, the first phase after molting, and then increase to a peak during early premolt. Ecdysteroid levels measured in fieldcollected diapausing C. pacificus CVs were lower than those in active CVs, as expected based on the predominance of the postmolt phase among diapausing CVs. Ecdysteroid analysis provides a faster, less labor-intensive alternative to jaw-phase analysis for identifying the molt phase of field-collected copepodids, and can provide valuable insights into their life-history status. Measurement of copepod hormonal status in situ may provide a direct means of determining the proximate cues for diapause induction and termination in oceanic copepods.

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Section: Discussionmentioning

confidence: 90%

Ecdysteroids in the oceanic copepod Calanus pacificus: variation during molt cycle and change associated with diapause

Johnson¹

2003

Mar. Ecol. Prog. Ser.

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“…5c,d) leads to the major question as to whether the observed relation between released chitobiase activity and secondary production is valid for copepods in general. In 3 Daphnia species, ratios between the total chitobiase activity in the animal and the glucosamine content of the cuticle differ by 3-fold (Espie & Roff 1995a). Also, no inverse relation exists between total chitobiase activity in the animal and duration of the moult cycle among these cladoceran species.…”

Section: Chitobiase Activity Measured In Crustacean Tissuementioning

confidence: 92%

“…Chitobiase activity in the animal varies strongly over the moult cycle in D, magna, with a 5-fold increase during detachment of the old exoskeleton from the epidermis before the actual moult. Moulting rate varies as a function of temperature and food concentration, and significant relations have been established between moulting rate (from independent incubations) and the mean chitobiase activity in homogenates, in both laboratory cultures of D. magna and a field population of D. rosea (Espie & Roff 1995a). Variation of chitobiase activity during the moult cycle is also known for a marine crustacean: Buchholz (1989) measured enzyme activity in isolated integuments of the krill Euphausia superba, and observed a 13-fold increase in chitobiase activity between Stages D1 and D2.…”

Section: Chitobiase Activity Measured In Crustacean Tissuementioning

confidence: 99%

Release of the enzyme chitobiase by the copepod Temora longicornis:characteristics and potential tool for estimating crustacean biomass production in the sea

Oosterhuis¹,

Baars²,

Breteler³

2000

Mar. Ecol. Prog. Ser.

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ABSTRACT. The chitlnolytic enzyme chitobiase (N-acetyl-P-D-glucosaminidase), which is expressed during the pre-moult phase of crustaceans, is released into the ambient water after shedding of the exuvium. We examined the potential use of chitobiase activity in water samples as a measure of secondary production of crustaceans. Chitobiase activity, expressed on the substrate 4-methylumbelliferyl-N-acetyl-P-D-glucosaminide (MUFNAG), was measured in experiments with the marine copepod Ternora longicornis, with focus on the dissolved ('free', c0.2 pm) fraction. Significant activity of free chitobiase was found in the ambient water of individual copepodites when they moulted to enter the next stage. The activity of the chitobiase released was linearly related to body weight and to the increment of body weight. In bacteria-poor water (filtered through 0.2 pm), no significant decrease of free T longicornis chitobiase occurred in the first 24 h. In non-manipulated water, the decay of free T. longicornis chitobiase by bacteria was exponential with time, with relative rates varying by 4 to 13% h-' at 15°C. The particle-bound chitobiase activity was related to the number of bacteria. Different sources of chitoblase could be distinguished by enzyme characteristics. The K, value of T longicornis chitobiase was 55 pm01 I-', comparable to values published for Daphnia species. In Oxyrrhis marina, a heterotrophic dinoflagellate serving as the main food item in the longicornis culture, enzyme assays indicated a K, < 0.2 pm01 1-'. Water predominantly containing bacteria showed a K, > 100 pm01 1-l. The usefulness of free chitobiase as a natural tracer of secondary production was tested in a culture vessel of T. longicornis. The rate of chitobiase release was derived from the chitobiase activity in the ambient culture water over time and the rate of decay in water samples devoid of copepods. From the relation between release of chitobiase and increase of body weight of moultlng copepodites, the total daily biomass increase in the culture vessel was calculated. These estimates compared well wlth classical monitoring of biomass changes. If this relation found in T. longicornis is representative of marine crustaceans in general, tracking of free chitobiase in water samples could be a biochemical tool for estimating in situ secondary production in natural waters.

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“…Samples were centrifuged for 10 min at 10 000g and 4 • C, and the resulting supernatants were recovered and used to analyze the chitobiase activity. Chitobiase activity was measured using the method described by Espie and Roff (1996). The chitobiase reaction used 4-methylumbelliferyl-N-acetyl-ß-D-glucosaminide (MUFNAG) as a substrate and generated the fluorescent 4-methylumbelliferone (MUF), which was evaluated.…”

Section: Chitobiase Activitymentioning

confidence: 99%

Effects of chlordecone on 20-hydroxyecdysone concentration and chitobiase activity in a decapod crustacean, Macrobrachium rosenbergii

et al. 2016

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a b s t r a c tChlordecone (CLD) is an organochlorine insecticide abundant in aquatic environment of the French West Indies. However, few studies have investigated its impact on freshwater invertebrates. Whereas CLD is suspected of inducing endocrine disruption, this work aimed to study the effects of environmentally relevant concentrations of CLD on the 20-hydroxyecdysone (20-HE) hormone concentration and on the chitobiase activity, both having key roles in the molting process of crustaceans. In addition, the bioaccumulation of CLD was measured in the muscle tissue of Macrobrachium rosenbergii to underline potential dose-response relationship. The results have shown that CLD was bioaccumulated in exposed organisms according to a trend to a dose-response relationship. Moreover, it was observed that CLD decreased the 20-HE concentration in exposed prawns when compared to control, whatever the duration of exposure, as well as it inhibited the chitobiase activity after 30 days of exposure. The present study indicates that CLD could interfere with molting process of M. rosenbergii by disturbing the 20-HE concentration and the activity of chitobiase, suggesting consequences at the long term on the shrimp development. This study also confirmed that CLD could be an endocrine disruptor in decapod crustaceans, as it was already observed in vertebrates.

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A biochemical index of duration of the molt cycle for planktonic Crustacea based on the chitin‐degrading enzyme, chitobiase

Cited by 34 publications

References 14 publications

Ecdysteroids in the oceanic copepod Calanus pacificus: variation during molt cycle and change associated with diapause

Ecdysteroids in the oceanic copepod Calanus pacificus: variation during molt cycle and change associated with diapause

Release of the enzyme chitobiase by the copepod Temora longicornis:characteristics and potential tool for estimating crustacean biomass production in the sea

Effects of chlordecone on 20-hydroxyecdysone concentration and chitobiase activity in a decapod crustacean, Macrobrachium rosenbergii

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