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1

Does crustacean ethoxyresorufin O-deethylase activity vary during the molting cycle?  

PubMed

The authors examined fluctuation in microsomal ethoxyresorufin O-deethylase (EROD) activity in the hepatopancreas during the molting cycle of the fiddler crab, Uca pugilator. Results showed that microsomal EROD activity fluctuates significantly during the molting cycle, with the lowest enzymatic activity occurring in the late premolt stage. These results clearly show that molting physiology influences crustacean EROD activity, suggesting that when using crustacean EROD assays in evaluating pollution, only individuals from the same molt stage should be used. The authors propose that the high level of EROD activity in postmolt and intermolt stages is an additional mechanism crustaceans use to prevent any untimely rise in ecdysteroid levels. PMID:23843096

Hotard, Kate; Zou, Enmin

2013-10-01

2

Stage-specific changes in calcium concentration in crustacean (Callinectes sapidus) Y-organs during a natural molting cycle, and their relation to the hemolymphatic ecdysteroid titer.  

PubMed

Secretion of ecdysteroid molting hormones by crustacean Y-organs is suppressed by molt-inhibiting hormone (MIH). The suppressive effect of MIH on ecdysteroidogenesis is mediated by one or more cyclic nucleotide second messengers. In addition, existing data indicate that ecdysteroidogenesis is positively regulated (stimulated) by intracellular Ca(++). Despite the apparent critical role of calcium in regulating ecdysteroidogenesis, the level of Ca(++) in Y-organ cells has not been previously measured during a natural molting cycle for any crustacean species. In studies reported here, a fluorescent calcium indicator (Fluo-4) was used to measure Ca(++) levels in Y-organs during a molting cycle of the blue crab, Callinectes sapidus. Mean calcium fluorescence increased 5.8-fold between intermolt (C4) and stage D3 of premolt, and then dropped abruptly, reaching a level in postmolt (A) that was not significantly different from that in intermolt (P>0.05). The level of ecdysteroids in hemolymph of Y-organ donor crabs (measured by radioimmunoassay) showed an overall pattern similar to that observed for calcium fluorescence, rising from 2.9 ng/mL in intermolt to 357.1 ng/mL in D3 (P<0.05), and then dropping to 55.3 ng/mL in D4 (P<0.05). The combined results are consistent with the hypothesis that ecdysteroidogenesis is stimulated by an increase in intracellular Ca(++). PMID:22683690

Chen, Hsiang-Yin; Dillaman, Richard M; Roer, Robert D; Watson, R Douglas

2012-06-07

3

Carbonic anhydrase activity in a calcium-mobilizing epithelium of the crustacean Orchestia cavimana during molting  

Microsoft Academic Search

We investigated the involvement of the enzyme, carbonic anhydrase, in the calcification-decalcification processes occurring in the posterior caeca of the midgut of the terrestrial crustacean, Orchestia cavimana, before and after exuviation. This enzyme was ultrahistochemically localized throughout the membranes of the caecal epithelium as well as extracellularly, i.e., within pre-exuvial calcareous concretions and postexuvial calcified spherules. During the molt cycle,

J. C. Meyran; F. Graf; J. Fournié

1987-01-01

4

Nontarget effects of the insecticide methoprene on molting in the estuarine crustacean Neomysis integer (Crustacea: Mysidacea)  

Microsoft Academic Search

Ecdysteroids, the molting hormones in crustaceans and other arthropods, play a crucial role in the control of growth, reproduction and embryogenesis of these organisms. Insecticides are often designed to target specific endocrine-regulated functions such as molting and larval development such as methoprene, a juvenile hormone analogue.The aim of this study was to examine the effects of methoprene on molting in

An Ghekiere; Tim Verslycke; Nancy Fockedey; Colin R. Janssen

2006-01-01

5

FIRST-CYCLE MOLTS IN NORTH AMERICAN FALCONIFORMES  

Microsoft Academic Search

I examined 1849 specimens of 20 North American Falconiform species to elucidate the occurrence and nomenclature of partial first-cycle molts. As reported in the literature, American Kestrel (Falco sparverius) and White-tailed Kite (Elanus leucurus) have relatively complete body-feather molts that occur during the first fall; in the kite, this molt can also include up to all rectrices and 2-6 secondaries,

PETER PYLE

6

Expression Analysis of Ecdysone Receptor and Ultraspiracle through Molting Period in Mysid Crustacean, Americamysis bahia  

Microsoft Academic Search

Ecdysteroids, primarily 20-hydroxyecdysone (20E), play a central role in the growth of arthropods. Molecular target of the ecdysteroids is known as a receptor complex composed of ecdysone receptor (EcR) and ultraspiracle (USP) protein. It is important to clarify the expression profile of EcR\\/USP in crustacean for understanding the endocrine disrupting effects of environmental xenobiotics on crustacean. However, despite EcR\\/USP has

Masashi HIRANO; Hiroshi ISHIBASHI; Ryoko YAMAUCHI

7

Calcium balance in crustaceans: nutritional aspects of physiological regulation  

Microsoft Academic Search

Calcium homeostasis in crustaceans is influenced by their natural molting cycle that periodically requires replacement of the calcified exoskeleton in order for growth to occur. Whole body Ca balance transitions from intermolt (zero net flux) to premolt (net efflux) and postmolt (net influx at the rate of 2 mmolkg?1h?1). As such, molting provides a convenient model to study up- and

F. P Zanotto; M. G Wheatly

2002-01-01

8

Molt-related susceptibility and regenerative limb growth as sensitive indicators of aquatic pollutant toxicity to crustaceans  

SciTech Connect

The study evaluated the comparative toxicity of various pollutants to intermolt and molting grass shrimp (Palaemonetes pugio). Most of the tested materials (pentachlorophenol, tetrachlorophenols, trichlorophenols, methylenebis dichlorophenol, dibutyl phthalate, chromium, and drilling mud) were more toxic to molting shrimp than to intermolt shrimp. Radio-tracer studies with 2,4,5-trichlorophenol and pentachlorophenol indicated that the increased susceptibility of newly molted shrimp is linked to increased pollutant uptake.

Rao, K.R.; Conklin, P.J.

1986-01-01

9

TNF-? induces apoptosis of Molt4 cells and cell cycle specificity of Bcl2 phosphorylation  

Microsoft Academic Search

Objective  The aim of the study was to observe the expression of Bcl-2 and its phosphorylation in Molt-4 cells induced by tumor necrosis\\u000a factor-? (TNF-?), and to investigate the possible mechanism of cell cycle specificity of apoptosis.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Exponentially growing Molt-4 cells were treated with TNF-?. Apoptosis was detected by DNA fragmentation assay. API method\\u000a was applied to illustrate the cell cycle

Changyong Yang; Huijie Zhao; Jianping Gong

2010-01-01

10

Role of ecdysteroids in the molting and reproductive cycles of the white shrimp, Penaeus vannamei  

SciTech Connect

The molt cycle was characterized in the white shrimp Penaeus vannamei based upon changes in the morphology of pleopod setae. These characters were used subsequently to determine changes in ecdysteroids and related biosynthetic events during the stages of the molting cycle and in relation to reproduction. Ecdysteroid titers were measured during the molting cycle. They increased during the premolt, decreased at ecdysis and remained minimal through the intermolt. 20-hydroxyecdysone (20-OHE) was the major ecdysteroid present during the premolt. Injection of ({sup 3}H)ecdysone resulted in label accumulation in the epidermis and hepatopancreas in the form of 20-OHE which was subsequently hydroxylated further to a polar metabolite. ({sup 3}H)ecdysone was not metabolized by the Y-organ, hemolymph, muscle or intestine. Eyestalk ablation elevated hemolymph ecdysteroid titers and reduced the duration of all molt stages. However, 20-OHE injection into intact animals caused a disproportionate reduction in the durations of only the intermolt and early premolt stages.

Chan, S.M.

1989-01-01

11

Molt Cycle of the Red-Backed Sandpiper (Calidris Alpina) in Western North America.  

National Technical Information Service (NTIS)

The pterylography, molts, molt schedule, and criteria for age determination of Calidris alpina along the west coast of North America are described. The relationships of molt with breeding and with migration are discussed for this species, which nests at a...

R. T. Holmes

1966-01-01

12

I. Muscle Structure at Molting  

Microsoft Academic Search

Rhodnius prolixus, a South American insect, molts five times in its development to an adult after emerging from the egg. Each molting cycle is triggered with a blood-meal. The ventral intersegmental abdominal muscles of Rhodnius develop during each molting cycle and are functional at molting. The fine structure of these fully developed muscles from fourth stage larval insects is studied.

INTERSEGMENTAL ABDOMINAL MUSCLES; PAUL A. TOSELLI; FRANK A. PEPE

13

Pterostilbene induces cell cycle arrest and apoptosis in MOLT4 human leukemia cells.  

PubMed

Pterostilbene, a polyphenolic compound present in grapes and other fruits, has been demonstrated to inhibit growth and induce apoptosis and autophagy in some cancer cell types. We found that pterostilbene at the IC(90) concentration of 44 µM inhibited proliferation and induced apoptosis in MOLT4 human leukemia cells. Treatment with pterostilbene resulted in a transient accumulation of cells in the G(0)/G(1)-cell cycle phase followed by the S-phase arrest. Pterostilbene-induced apoptotic death of MOLT4 cells was mediated by caspase-3 activation and was accompanied by the disruption of mitochondrial membrane potential, phosphatidylserine externalization and internucleosomal DNA fragmentation. Our results suggest that pterostilbene could serve as a potential additional chemotherapeutic agent for the treatment of leukemia. PMID:23264221

Siedlecka-Kroplewska, Kamila; Jozwik, Agnieszka; Kaszubowska, Lucyna; Kowalczyk, Anna; Boguslawski, Wojciech

2012-01-01

14

Cloning of prophenoloxidase from hemocytes of the blue crab, Callinectes sapidus and its expression and enzyme activity during the molt cycle.  

PubMed

The arthropods cuticle undergoes dramatic morphological and biochemical changes from being soft to hardness through each molting process. Prophenoloxidase (PPO) known as a key enzyme in the arthropod innate immune system involved in the melanization reaction, has been related with the initial shell-hardening process, specifically in the sclerotization of the protein matrix in the new cuticle. Since hemocytes have been reported as the main PPO source in arthropods, the transport of hemocyte PPO into the newly laid, soft cuticle has been proposed for shell-hardening occurring during and immediately after ecdysis. In order to define the role of hemocyte PPO in the shell-hardening of crustaceans, the full-length cDNA sequence (2806 nt) of hemocytes PPO of the blue crab Callinectes sapidus (CasPPO-hemo) is isolated using degenerate PCR and 5'-3' RACE. CasPPO-hemo encodes a putative PPO (672 aa) showing three hemocyanin domains: N, M, and C in order and two copper binding sites (CuA & CuB). The sequence analysis identifies the putative CasPPO-hemo as zymogen which requires the cleavage at the N-terminus for its activation. Hemocyte extract (CasHLS) contains the PO, the activity of which depends on the in vitro activation of trypsin. The expression levels of CasPPO-hemo are kept constant during the molt cycle. The increase in the number of hemocytes at early premolt correlates with the elevated PO activity, while at late premolt, the increment in hemocyte numbers does not reflect on the PO activity. The functional importance of the changes in the levels of CasHLS-PO activity during molt cycle is discussed in relation to cuticle hardening process. PMID:23968691

Alvarez, Javier V; Chung, J Sook

2013-08-20

15

Surveillance of Salmonella populations, prevalence and serotype diversity in layer feces as a function of production cycle and molting  

Microsoft Academic Search

Salmonella species are recognized as a major cause of foodborne illnesses that are closely associated with the consumption of contaminated poultry and egg products. The objective of this study was to determine whether the hen's laying cycle and the practice of reduced caloric intake molting influenced the prevalence and populations of Salmonella in layer feces and to evaluate the serotype

B. W. SHELDON; X. LI; J. B. PAYNE; F. B. O. SANTOS; K. E. ANDERSON

16

Organic and inorganic compound variations in haemolymph, epidermal tissue and cuticle over the molt cycle in Scylla serrata (Decapoda)  

Microsoft Academic Search

Analysis of organic and inorganic compounds in haemolymph, epidermal tissue and cuticle, allowed the correlation of their content variation during the molt cycle in Scyllaserrata (Decapoda). The extrusion of carbohydrate, chitin, H2O- and NaOH-soluble proteins of the epidermal tissue from D2 stage on suggested an early formation of the organic fraction in the new cuticle. The additional secretion of HCl-soluble

Boonyarath Pratoomchat; Pichan Sawangwong; Pannee Pakkong; Jorge Machado

2002-01-01

17

The mechanism of sensory transduction in a mechanoreceptor. Functional stages in campaniform sensilla during the molting cycle  

PubMed Central

This paper describes the ultrastructural modifications that cockroach campaniform sensilla undergo at three major stages in the molting cycle and finds that the sensilla are physiological functional at all developmental stages leading to ecdysis. Late stage animals on the verge of ecdysis have two completely separate cuticles. The campaniform sensillum sends a 220-mum extension of the sensory process through a hole in its cap in the new (inner) cuticle across a fluid-filled molting space to its functional insertion in the cap in the old (outer) cuticle. Mechanical stimulation of the old cap excites the sensillum. The ultrastructural geometry of late stage sensilla, coupled with the observation they are physiolgically functional, supports the hypotheses (a) that sensory transduction occurs at the tip of the sensory process, and (b) that cap identation causes the cap cuticle to pinch the tip of the sensory process, thereby stimulating the sensillum.

1976-01-01

18

Influence of molt cycle and beta-ecdysone on protein synthesis in the chelicerate arthropod, Limulus polyphemus.  

PubMed

1. The effect of molt cycle stage and beta-ecdysone on protein synthesis in the horsehoe crab, Limulus polyphemus, was examined. 2. A pronounced decline in protein specific radioactivity after incubation with 14C-leucine was noted in muscle, midgut gland and operculum from postmolt to intermolt to premolt and in gut and gill tissue from intermolt to premolt. 3. beta-Ecdysone injections produced an early stimulation of protein synthesis in the midgut gland followed by strong inhibition within 48 hr. 4. Results are compared with those obtained in mandibulate arthropods. PMID:95691

Winget, R R; Herman, W S

1979-01-01

19

Ecdysteroid metabolism in crustaceans.  

PubMed

The molting gland, or Y-organ (YO), is the primary site for ecdysteroid synthesis in decapod crustaceans. Ecdysteroid biosynthesis is divided into two stages: (1) conversion of cholesterol to 5?-diketol and (2) conversion of 5?-diketol to secreted products. Stage 1 involves the conversion of cholesterol to 7-dehydrocholesterol (7DC) by 7,8-dehydrogenase, the "Black Box" reactions involving 3-oxo-?(4) intermediates, and the conversion of ?(4)-diketol to 5?-diketol by 5?[H]-reductase. The stage 2 reactions generate four major products, depending on species: ecdysone, 3-dehydroecdysone (3DE), 25-deoxyecdysone (25dE), and 3-dehydro-25-deoxyecdysone (3D25dE). Peripheral tissues convert these compounds to the active hormones 20-hydroxyecdysone (20E) and ponasterone A (25-deoxy-20-hydroxyecdysone or 25d20E). The hydroxylations at C25, C22, C2, and C20 are catalyzed by cytochrome P-450 mono-oxygenases, which are encoded by the Halloween genes Phantom, Disembodied, Shadow, and Shade, respectively, in insects. Orthologs of these genes are present in the Daphnia genome and a cDNA encoding Phantom has been cloned from prawn. Inactivation involves conversion of ecdysteroids to polar metabolites and/or conjugates, which are eliminated in the urine and feces. The antennal gland is the major route for excretion of ecdysteroids synthesized by the YO. The hepatopancreas eliminates ingested ecdysteroids by forming apolar conjugates. The concentrations of ecdysteroids vary over the molt cycle and are determined by the combined effects biosynthesis, metabolism, and excretion. PMID:20837145

Mykles, Donald L

2010-09-15

20

PHYSIOLOGY, ENDOCRINOLOGY, AND REPRODUCTION The Effect of an Induced Molt and a Second Cycle of Lay on Skeletal Integrity of White Leghorns1  

Microsoft Academic Search

The effect of an induced molt and a second egg laying cycle on White Leghorns hen's skeletal integ- rity was investigated in a series of 3 experiments. Using dual-energy X-ray absorptiometry, bone mineral density (BMD) and bone mineral content (BMC) of the left tibia and humerus were measured in live hens and excised bones and correlated with invasive bone measurement

H. Mazzuco; P. Y. Hester

21

Ecdysteroid metabolism in crustaceans  

Microsoft Academic Search

The molting gland, or Y-organ (YO), is the primary site for ecdysteroid synthesis in decapod crustaceans. Ecdysteroid biosynthesis is divided into two stages: (1) conversion of cholesterol to 5?-diketol and (2) conversion of 5?-diketol to secreted products. Stage 1 involves the conversion of cholesterol to 7-dehydrocholesterol (7DC) by 7,8-dehydrogenase, the “Black Box” reactions involving 3-oxo-?4 intermediates, and the conversion of

Donald L. Mykles

22

Primary molt of California condors  

USGS Publications Warehouse

Primary molt of the California Condor (Gymnogyps californianus) was studied intensively from 1982 through 1985, using repeated flight photographs of the remaining individuals in the wild population as a basis for most analyses. On the average, wild condors replaced 4.4 of the 8 emarginated primaries on each wing each year. The sepcific primaries molted were generally the ones missed in the previous year and were usually well-distributed among the eight possibilities, with a tendency for low-numbered primaries to molt earlier than high-numbered primaries. Within individuals, molt of one wing was commonly very different from that of the other wing. Primarily molt of captive juveniles was similar to that of wild juveniles. The interval from loss to full replacement of individual primary feathers was normally 3 1/2 to 4 months, with the primaries closest to the leading edge of the wing growing most slowly. Most primarities were shed between 1 February and 1 September. Primaries lost in late fall and early winter were not replaced until the following summer, indicating interrupted molt over the winter. In general, primary molt of the condor differs from that of smaller cathartids in being highly seasonal, highly variable in sequence, highly asymmetric between wings, and in following a roughly 2-year cycle. Molt of the condor shows many similarities to that of the White Stork (Ciconia ciconia) and to that of large accipitrid vultures.

Snyder, N.F.R.; Johnson, E.V.; Clendenen, D.A.

1987-01-01

23

Molting Mania  

ERIC Educational Resources Information Center

|Most children are unaware of the process of molting, the periodic shedding and replacement of part or all of a coat or an outer covering of an animal, but it is an animal characteristic they are sure to be interested in and should have the opportunity to observe. In this article, the author shares how she and her students observed various…

Arce, Christina

2006-01-01

24

Cell Cycle-related Expression of p120 Nucí colar Antigen in Normal Human Lymphocytes and in Cells of HL60 and MOLT4 Leukemic Lines: Effects of Methotrexate, Camptothecin, and Teniposide1  

Microsoft Academic Search

Expression of the proliferation-associated nucleolar antigen pi 20 was studied by flow cytometry in human quiescent and phytohemagglutinin- stimulated lymphocytes, as well as in human lymphocytic (MOLT-4) and promyelocytic (HL-60) cell lines. Divariate analysis of pl20 and DNA content made it possible to correlate p120 expression with cell position in the cycle. Proliferating lymphocytes and MOLT-4 and HL- 60 cells

Wojciech Gorczyca; Silvia Bruno; Myron R. Melamed; Zbigniew Darzynkiewicz

25

Immunohistochemical and morphological studies of hyperglycemic hormone-and molt-inhibiting hormone-producing cells in the eyestalk of kuruma prawn, Penaeus japonicus, in relation to molting  

Microsoft Academic Search

The objective of this study is to explore if immunohistochemical and morphological changes occur in crustacean hyperglycemic hormone (CHH, Pej-SGP-III)-and molt-inhibiting hormone (MIH, Pej-SGP-IV)- producing cells during molt stages. Consecutive sections prepared from immature female eyestalks at different molt stages were stained immunohistochemically. Neurosecretory cells producing each of Pej-SGP-III (Pej-SGP-III cells, CHH cells) and Pej-SGP-IV (Pej-SGP-IV cells, MIH cells) were

TUNG-WEI SHIH; YUZURU SUZUKI; HIROMICHI NAGASAWA; KATSUMI AIDA

2003-01-01

26

Control of molting in crustacea  

SciTech Connect

The single, overriding event that occurs during all proecdysial periods in crustaceans is the synthesis of a new exoskeleton that encompasses an enlarged animal when the old shell is cast off. Regeneration of missing appendages and larval or puberty metamorphoses also occur during proecdysis. Proecdysial periods have been divided into substages defined by the occurrence of specific events. Although a number of factors must be postulated to account for individual proecdysial events, only the molting hormone, 20-hydroxyecdysone, has been identified and isolated. Much evidence indicates that the X-organ sinus glands complex, a neurosecretory tissue located in the eyestalks, is the source of a molt inhibiting hormone (MIH) responsible for maintaining animals in anecdysis. An exuviation factor has been proposed to support the extrication of the animal from the old exoskeleton. There is evidence for a limb growth inhibitory factor (LGIF) that affects the rate of growth of regenerating limbs. We are proposing an anecdysial limb autotomy factor (LAF/sub an/) that propels into precocious molts anecdysial limb autotomy factor (LAF/sub pro/) that interrupts the proecdysial period of animals that lose one or more normal or partially regenerated pereopods before a critical time in proecdysis.

Skinner, D.M.; Graham, D.E.; Holland, C.A.; Mykles, D.L.; Soumoff, C.; Yamaoka, L.H.

1982-01-01

27

Molt cycle related changes and effect of short term starvation on the biochemical constituents of the blue swimmer crab Portunus pelagicus  

PubMed Central

Synthesis and hardening of a new exoskeleton are essential to the arthropod molting process. The present study emphasizes the variations in the levels of hemolymph total free sugars, hepatopancreas glycogen and cuticular proteins during the molting stages of Portunus pelagicus. It also reports the effect of short-term starvation conditions on the biochemical constituents of the hemolymph. Intermolt crabs were subjected to 6 days of starvation and hemolymph samples were taken. Standard biochemical procedures were followed toward the quantification of total proteins, total free sugars and total lipids. The total free sugar level in the hemolymph of P. pelagicus was observed to increase during early premolt D0 (3.108 ± 0.032 g/ml) and a gradual decrease till late postmolt B stage (0.552 ± 0.124 g/ml), suggesting the need for total free sugars to provide energy for the apolysis process. Increase in the levels of hepatopancreas glycogen was observed from 1225 ± 0.04 ?g/mg in early premolt D0 to 1700 ± 0.3 ?g/mg in late premolt D2–3. This is in correlation with the decreased levels of free sugars during premolt stages, suggesting an increase in the storage of glycogen reserves in the hepatopancreas. Cuticular proteins increased during stage B (2.702 ± 0.093 g/ml) and stage C (3.065 ± 0.012 g/ml), indicating exoskeleton hardening and mineralization. Results of the starvation studies clearly showed a steady decline in the level of total free sugars till day 6 (0.099 ± 0.00 g/ml) when compared to the control (8.646 ± 0.08 g/ml). Gradual decrease of total lipids was also observed from the first day of the experiment (6.088 ± 2.44 g/ml) to the last day of the study (0.401 ± 0.20 g/ml) which was 85% lesser than the control (8.450 ± 0.49 g/ml)suggesting the efficient usage of total sugars to consolidate the loss of energy reserves during starvation. The knowledge of Molt-cycle events can be used as a tool for the evaluation of the developmental state providing a morphological reference system for physiological and biochemical studies related to crab aquaculture. Starvation studies enlightens that increasing carbohydrate levels in crab feed together with good protein content could alleviate the natural effects of starvation, improve farm productivity and reduce the deleterious impact of nitrogen pollution generated by rich-protein feeds used in crab farming.

Sugumar, V.; Vijayalakshmi, G.; Saranya, K.

2012-01-01

28

crustaceans drawer  

NSDL National Science Digital Library

Crustaceans are arthropods with two pairs of antennae in front of the mouth, and one pair grinding or biting limbs (mandibles) behind the mouth. The group includes crabs, lobsters, shrimp and the extinct phyllocarids.

2001-03-01

29

Qualitative and quantitative changes in exoskeletal proteins synthesized throughout the molt cycle of the Bermuda land crab  

SciTech Connect

During the premolt period in Crustacea, a single layer of epidermal cells that underlies the exoskeleton is thought to be responsible for the degradation of the old exoskeleton and synthesis of a new one. In order to identify molt-specific proteins and their temporal appearance, they cultured epidermis and associated integumentary tissue from the gill chambers of crab in vitro in the presence of one of three radiolabeled amino acids. Autoradiographs of (/sup 35/S)Met-labeled tissues indicate a low level of synthesis in epidermal cells of intermolt animals; synthesis increases during premolt and stage B of postmolt. Label is also found in the innermost layer of the old exoskeleton while it is being degraded and in new exoskeletal layers during their synthesis. Fluorographs of gels of integumentary proteins show marked quantitative changes in 44 and 56 kD proteins late in premolt. Qualitative changes include synthesis of 46 and 48 kD proteins during late premolt and three proteins (all of approx. 170 kD) detectable only in postmolt. Solubilized gel slices of (/sup 3/H)Leu-labeled proteins indicate maximum synthesis at an earlier premolt stage than seen in Met-labeled proteins. Other proteins of 20, 24, 29, 32, and 96 kD are synthesized in a stage-dependent manner while (/sup 3/H)Tyr labels small proteins that appear only in late premolt.

Stringfellow, L.A.; Skinner, D.M.

1987-05-01

30

Effects of endosulfan exposure and Taura Syndrome Virus infection on the survival and molting of the marine penaeid shrimp, Litopenaeus vannamei.  

PubMed

Molting in crustaceans is an important endocrine-controlled biological process that plays a critical role in growth and reproduction. Many factors can affect this physiological cycle in crustaceans including environmental stressors and disease agents. For example the pathology of Taura Syndrome Virus (TSV) of shrimp is closely related to molting cycle. Similarly, endosulfan, a commonly used pesticide is a potential endocrine disruptor. This study explores interrelationships between pesticide exposure, virus infection and their interactions with physiology and susceptibility of the shrimp. Litopenaeus vannamei (Pacific white shrimp) were challenged with increasing doses of endosulfan and TSV (TSV-C, a Belize reference strain) to determine the respective median lethal concentrations (LC(50)s). The 96-h endosulfan LC(50) was 5.32 ?g L(-1), while the 7-d TSV LC(50) was 54.74 mg L(-1). Subsequently, based on their respective LC(50) values, a 20-d interaction experiment with sublethal concentrations of endosulfan (2 ?g L(-1)) and TSV (30 mg L(-1)) confirmed a significant interaction (p<0.05, ?(2)=5.29), and thereby the susceptibility of the shrimp. Concurrently, molt-stage of animals, both at the time of exposure and death, was compared with mortality. For animals challenged with TSV, no strong correlation between molt-stage and mortality was observed (p>0.05). For animals exposed to endosulfan, animals in the postmolt stage were shown to be more susceptible to acute toxicity (p<0.05). For animals exposed to both TSV and endosulfan, interference of endosulfan-associated stress lead to increasingly higher susceptibility at postmolt (p<0.05) during the acute phase of the TSV disease cycle. PMID:22119282

Tumburu, Laxminath; Shepard, Eleanor F; Strand, Allan E; Browdy, Craig L

2011-11-25

31

Testing competing hypotheses for chronology and intensity of lesser scaup molt during winter and spring migration  

USGS Publications Warehouse

We examined chronology and intensity of molt and their relationships to nutrient reserves (lipid and protein) of Lesser Scaup (Aythya affinisK/i>) to test predictions of two competing hypotheses. The "staggered cost" hypothesis states that contour-feather molt is nutritionally costly and should not occur during nutritionally costly periods of the annual cycle unless adequate nutrients are available. The "breeding plumage" hypothesis states that prealternate molt must be complete prior to nesting, regardless of nutrient availability. Males and females were completing prebasic molt during winter (Louisiana) and had similar molt intensities. Females underwent prealternate molt during spring migration (Illinois and Minnesota) and prebreeding (Manitoba) periods; 53% and 93% of females were in moderate to heavy molt in Minnesota and Manitoba, respectively, despite experiencing other substantial nutritional costs. Intensity of prealternate molt was not correlated with lipid reserves even though females, on average, were nutritionally stressed. Molt intensity was not negatively correlated with protein reserves at any location. Chronology and intensity of prealternate molt varied little and were not temporally staggered from other nutritionally costly events. Prealternate molt did not influence nutrient reserves, and nutrient reserves likely were not the ultimate factor influencing chronology or intensity of prealternate molt of females. We surmise that nutrients required for prealternate molt come from exogenous sources and that the "staggered cost" hypothesis does not explain chronology of prealternate molt in female Lesser Scaup; rather, it appears that molt must be complete prior to nesting, consistent with the "breeding plumage" hypothesis.

Anteau, Michael J.; Anteau, Andrea C. E.; Afton, Alan D.

2011-01-01

32

The lunar-tide cycle viewed by crustacean and mollusc gatherers in the State of Paraíba, Northeast Brazil and their influence in collection attitudes.  

PubMed

Traditional human communities have a wide knowledge of their environment. Collection of animals in estuarine and coastal areas are directly influenced by tidal cycles. The aim of this study is to evaluate the understanding of the tides associated with the lunar cycle held by people who gather crustaceans and molluscs in the State of Paraiba. The empirical knowledge of 20 crab gatherers and 30 mollusc gatherers was recorded through open interviews and structured questionnaires. The results showed that the gatherers have an accurate comprehension of tidal phenomenon based on their exploitation of natural resources, which perpetuates through generations. PMID:16393342

Nishida, Alberto K; Nordi, Nivaldo; Alves, Rômulo R N

2006-01-04

33

Stimulation of molting in megalopae of the Asian shore crab Hemigrapsus sanguineus: physical and chemical cues  

Microsoft Academic Search

The Asian shore crab Hemigrapsus sanguineus is a recent invader and abundant mem- ber of rocky intertidal coastlines of the eastern USA. Understanding factors influencing the settlement and metamorphosis of its larvae is important for predict- ing colonization of the species. For many species of brachyuran crustaceans studied to date, chemical cues in the natural environment stimulate molting of megalopae,

Nancy J. O'Connor

2007-01-01

34

Influence of hen age and molting treatments on shell egg exterior, interior, and contents microflora and Salmonella prevalence during a second production cycle.  

PubMed

The objective of this study was to determine if increasing hen age and 3 different molting treatments influenced the total microflora counts or the prevalence of Salmonella spp. on the exterior of the egg shell, within the interior shell, or in the contents. Eggs from Hy-Line W-98 and Bovans White layer strains were sampled approximately every 28 d from 70 to 114 wk of age, with the molting period from 66 to 70 wk of age. Layers were utilized from the 35th North Carolina Layer Performance and Management Test and managed under identical husbandry practices. This study consisted of nonfasted, nonmolted, and feed-restricted treatments with the use of 135 eggs per layer strain, for a total of 270 eggs sampled per period. The exterior, interior shell, and contents were spiral plated onto plate count agar to calculate the total aerobic counts. Additional preenrichment, enrichment, conformational, and biochemical procedures were performed to test for the presence of Salmonella spp. Hen age and molting treatment significantly (P < 0.05) affected the microbial loads on all 3 egg components. Exterior, interior, yolk, and albumen counts increased during the molt period to as much as 1 log unit higher than the highest countable plate, which was 10(5). Exterior, interior, and contents counts significantly increased (P < 0.05) during period 15, with a significant increase (P < 0.05) in the interior also in period 14, and in the contents in periods 14 and 17. There were a total of 360 egg pools, and of those, 4 were positive Salmonella samples. Both the interior and exterior shell components and 2 of the 3 molting treatments had positive samples. Of these positives, 4 were confirmed as Salmonella Braenderup. Three positives were associated with the interior component, whereas 1 positive was associated with the exterior shell component. Three of the 4 samples were related to the nonfasted treatment, whereas the remaining positive was found in the non-molted treatment. PMID:18809879

Kretzschmar-McCluskey, V; Curtis, P A; Anderson, K E; Kerth, L K; Berry, W D

2008-10-01

35

Further Studies on Signaling Pathways for Ecdysteroidogenesis in Crustacean Y-Organs  

Microsoft Academic Search

SYNOPSIS. The Y-organs of crustaceans secrete ecdysteroids (molting hormones) and are regulated (negatively) by a neurosecretory peptide, molt-inhibiting hor- mone (MIH). Signaling path(s) in Y-organs were explored that connect MIH re- ceptors ultimately with suppression of receptor number for the uptake of choles- terol (ecdysteroid precursor) and of gene expression of steroidogenic enzymes. Ex- periments were conducted in vitro with

Eugene Spaziani; Thomas C. Jegla; Wenan L. Wang; Jeffrey A. Booth; Shanon M. Connolly; Corey C. Conrad; Matt J. Dewall; Christopher M. Sarno; Danice K. Stone; Rex Montgomery

2001-01-01

36

Effects of non-feed removal molting methods on egg quality traits in commercial brown egg laying hens in Turkey  

Microsoft Academic Search

Non-feed removal molting programme in commercial brown laying hens and its influence on pre-molting, post-molting and end\\u000a of cycle egg quality traits were investigated. Overall 54 birds were randomly divided into three treatment groups and each\\u000a group was fed with one of the following diets during 10 days of molting period: (i) grain barley, (ii) alfalfa meal, or (iii)\\u000a commercial

Metin Petek; S. Sule Gezen; Fazli Alpay; Recep Cibik

2008-01-01

37

Toward a unified model of developmental timing: A "molting" approach.  

PubMed

Animal development requires temporal coordination between recurrent processes and sequential events, but the underlying timing mechanisms are not yet understood. The molting cycle of C. elegans provides an ideal system to study this basic problem. We recently characterized LIN-42, which is related to the circadian clock protein PERIOD, as a key component of the developmental timer underlying rhythmic molting cycles. In this context, LIN-42 coordinates epithelial stem cell dynamics with progression of the molting cycle. Repeated actions of LIN-42 may enable the reprogramming of seam cell temporal fates, while stage-specific actions of LIN-42 and other heterochronic genes select fates appropriate for upcoming, rather than passing, life stages. Here, we discuss the possible configuration of the molting timer, which may include interconnected positive and negative regulatory loops among lin-42, conserved nuclear hormone receptors such as NHR-23 and -25, and the let-7 family of microRNAs. Physiological and environmental conditions may modulate the activities of particular components of this molting timer. Finding that LIN-42 regulates both a sleep-like behavioral state and epidermal stem cell dynamics further supports the model of functional conservation between LIN-42 and mammalian PERIOD proteins. The molting timer may therefore represent a primitive form of a central biological clock and provide a general paradigm for the integration of rhythmic and developmental processes. PMID:24058853

Monsalve, Gabriela C; Frand, Alison R

2012-10-01

38

Molt frequency of the isopod Porcellio scaber, as a measure of zinc-contaminated food  

Microsoft Academic Search

The effect of zinc-contaminated leaf litter (250--10,000 μg\\/g dry wt.) diets on molting in Porcellio scaber, a terrestrial isopod was measured under controlled conditions. The duration of the premolt stage, the period between two successive ecdyses and the rate of molting, was followed during the exposure. Increased zinc concentration in the food caused prolongation of the molt cycle and decreased

Damjana Drobne; J. Strus

1996-01-01

39

Flexibility and constraints in the molt schedule of long-distance migratory shorebirds: causes and consequences  

PubMed Central

Molt is a major component of the annual cycle of birds, the timing and extent of which can affect body condition, survival, and future reproductive success through carry-over effects. The way in which molt is fitted into the annual cycle seems to be a somewhat neglected area which is both of interest and of importance. Study of the causes of annual variation in the timing of molt and its potential consequence in long-distance migratory birds was examined using the Curlew Sandpiper, Calidris ferruginea, as a model species. Using the maximum likelihood molt models of Underhill and Zucchini (1988, Ibis 130:358–372), the relationship between annual variability in the start dates of molt at the population level with conditions on the breeding area was explored. Adult males typically started early in years when temperature in June on the Arctic breeding grounds were high compared to cold years while adult females molted later in years of high breeding success and/or warm July temperature and vice versa. When molt started later, the duration was often shorter, indicating that late completion of molt might have fitness consequences, probably jeopardizing survival. Evidence of this was seen in the low body condition of birds in years when molt was completed late. The results indicate that these migratory shorebirds follow a fine-tuned annual life cycle, and disturbances at a certain stage can alter next biological events through carry-over effects.

Barshep, Yahkat; Minton, Clive D T; Underhill, Les G; Erni, Birgit; Tomkovich, Pavel

2013-01-01

40

Flexibility and constraints in the molt schedule of long-distance migratory shorebirds: causes and consequences.  

PubMed

Molt is a major component of the annual cycle of birds, the timing and extent of which can affect body condition, survival, and future reproductive success through carry-over effects. The way in which molt is fitted into the annual cycle seems to be a somewhat neglected area which is both of interest and of importance. Study of the causes of annual variation in the timing of molt and its potential consequence in long-distance migratory birds was examined using the Curlew Sandpiper, Calidris ferruginea, as a model species. Using the maximum likelihood molt models of Underhill and Zucchini (1988, Ibis 130:358-372), the relationship between annual variability in the start dates of molt at the population level with conditions on the breeding area was explored. Adult males typically started early in years when temperature in June on the Arctic breeding grounds were high compared to cold years while adult females molted later in years of high breeding success and/or warm July temperature and vice versa. When molt started later, the duration was often shorter, indicating that late completion of molt might have fitness consequences, probably jeopardizing survival. Evidence of this was seen in the low body condition of birds in years when molt was completed late. The results indicate that these migratory shorebirds follow a fine-tuned annual life cycle, and disturbances at a certain stage can alter next biological events through carry-over effects. PMID:23919143

Barshep, Yahkat; Minton, Clive D T; Underhill, Les G; Erni, Birgit; Tomkovich, Pavel

2013-05-23

41

Molt chronology of northern pintails in California  

USGS Publications Warehouse

Intensity and chronology of molt in 10 feather groups (head, neck, breast, belly, back, rump, side, scapular, tertial, and tail) were measured using percentages of developing feathers (pinfeathers) converted to molt scores (0-100) in samples plucked monthly from northern pintails (Anas acuta) collected by shooting from August through March 1980-82 in the Sacramento Valley, California. Data to supplement sample size of immatures were obtained from October 1982 through January 1983. Molt scores of the prealternate molt peaked (30-40% pinfeathers) in immature and adult females and adult males in October when nearly all feather groups were molting. The prealternate molt in immature males did not peak until November. Adult males nearly completed this molt by December; no new feather growth occurred after January. Immature males were still growing new neck, side, rump, scapular, and tertial feathers in December. Molt scores of the prebasic molt among adult and immature females peaked (30-40% new growth) in February in both years. The prealternate molt of breast and belly feathers (both sexes) peaked earlier (Sep) than molt of most other feathers (Oct). Increased molt scores in peak months were a function of a disproportionate increase of molt activity within each feather group and the number of feather groups with molt. Molt scores of the prebasic molt in adult females were less during December and January of the dry (1980-81) than the wet (1981-82) winter. Restriction or delay of molt may conserve energy or other nutrients during poor habitat conditions.

Miller, M. R.

1986-01-01

42

What do we (need to) know about the melatonin in crustaceans?  

PubMed

Melatonin (N-acetyl-5-methoxy-tryptamine) was first discovered from the bovine pineal gland extract in 1958. Since then, its synthesis, metabolism, physiological, and patho-physiological functions are well studied in vertebrates; there is an increasing recognition of melatonin in invertebrates and especially in crustaceans. The presence of melatonin in crustaceans is now well documented and some functional aspects in the framework of crustacean biology have been demonstrated. This review aims at giving a comprehensive overview of the various physiological events regulated by this pleiotropic hormone. Topics include: glucose homeostasis, regulation of reproduction, molting, limb regeneration, and antioxidant properties. Finally, perspectives on current and possible research are offered. PMID:23650247

Sainath, S B; Swetha, Ch; Reddy, P Sreenivasula

2013-05-06

43

UTILIZATION OF ALFALFA AS A POTENTIAL MOLTING DIET FOR LAYING HENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Molting is a process by which a hen's reproductive tract is rejuvenated prior to the beginning of a laying cycle. This process is often artificially induced in commercial settings in order to extend the productive life of a flock of hens. The most common method for the induction of molt is feed de...

44

Glycogen storage in relation to the moult cycle in the two crustaceans Emerita asiatica and Ligia exotica  

Microsoft Academic Search

InEmerita asiatica, the quantitative fluctuations in the glycogen content of the hepatopancreas were markedly related to the moult cycle. The glycogen content of the hepatopancreas was maximum during premoult stages. It has been suggested that reserve glycogen, in addition to meeting general metabolic needs, may be especially involved in the genesis of the sugar precursors of chitin. The marked fall

K. Parvathy

1971-01-01

45

Crustaceans of Southern Australia  

NSDL National Science Digital Library

This intriguing resource on the Crustaceans of Southern Australia is provided by Dr. Gary Poore of the Museum of Victoria. Hundreds of images offer a peak into the diverse and colorful underwaters of Australia; images are accompanied by concise text, offering solid introductory information on the biology of marine crustaceans. Users will find this a worthy educational tool to learn more about Australian crustaceans from barnacles to crabs, ghost shrimps to lobsters.

1998-01-01

46

The effects of intense wing molt on diving in alcids and potential influences on the evolution of molt patterns.  

PubMed

Large and medium-sized alcids have a very intense wing molt wherein many flight feathers are shed in rapid succession and wing surface area is reduced by as much as 40%. Although these birds are rendered flightless during wing molt, they must still use their wings to propel themselves underwater. A molt-induced loss of wing area could simply reduce wing propulsion such that more muscular work would be required to maintain a given speed. Alternatively, molt could reduce drag on the wings, making a bird more penguin-like and actually enhancing diving ability. I addressed this issue by filming captive common guillemots Uria aalge and tufted puffins Fratercula cirrhata using an array of video cameras to plot the birds' movements in three dimensions. From these coordinate data I calculated swimming velocities, angles of descent and absolute depths. These values allowed me to estimate the forces due to drag and buoyancy that must be counteracted by flapping, which in turn yielded estimates of the amount of work generated during each flap as well as the average power and cost of transport. Within-bird comparisons of diving performance when wings were intact and during several stages of wing molt indicated that molt is associated with more frequent flapping, reduced displacement during the flap cycle, and possibly reduced work per flap. These negative effects on diving may explain why primary and secondary molts were offset in the birds I studied such that the period during which all of the flight feathers are effectively missing is minimized. PMID:15277555

Bridge, Eli S

2004-08-01

47

Methods and Compositions of Ecdysozoan Molt Inhibition.  

National Technical Information Service (NTIS)

In general, this invention relates to nucleic acid and amino acid sequences involved in molting and the use of these sequences as targets for the development of compounds that disrupt Ecdysozoan molting, and are useful as insecticides, nematicides, and an...

A. Frand G. Ruvkun

2003-01-01

48

Digestive proteinases of red shrimp Pleoticus muelleri (Decapoda, Penaeoidea): partial characterization and relationship with molting  

Microsoft Academic Search

The present study describes the activity and some characteristics of proteinases in the hepatopancreas of red shrimp Pleoticusmuelleri during the different stages of the molting cycle. Proteolytic activity was highest between pH 7.5 and 8. The hepatopancreatic protein content in the premolt stage was higher than in the other stages of the molting cycle (P<0.05). No significant differences were found

A. V. Fernandez Gimenez; F. L Garc??a-Carreño; M. A Navarrete del Toro; J. L Fenucci

2001-01-01

49

Least squares estimation of avian molt rates  

USGS Publications Warehouse

A straightforward least squares method of estimating the rate at which birds molt feathers is presented, suitable for birds captured more than once during the period of molt. The date of molt onset can also be estimated. The method is applied to male and female mourning doves.

Johnson, D. H.

1989-01-01

50

Chemosensory Sensilla in Crustaceans  

Microsoft Academic Search

\\u000a Crustaceans, like most other animals, have two types of chemosensory organs. In crustaceans these organs consist of sensilla\\u000a that differ structurally as well as functionally. Unimodal olfactory sensilla are usually considered as more long-range and\\u000a bimodal chemo- and mechanosensory sensilla as short-range or contact chemosensory sensilla. All chemosensory sensilla are\\u000a characterized by the presence of ciliated bipolar sensory cells. The

Eric Hallberg; Malin Skog

51

RESEARCH ARTICLE Rheb, an activator of target of rapamycin, in the blackback land crab, Gecarcinus lateralis: cloning and effects of molting and unweighting on expression in skeletal muscle  

Microsoft Academic Search

SUMMARY Molt-induced claw muscle atrophy in decapod crustaceans facilitates exuviation and is coordinated by ecdysteroid hormones. There is a 4-fold reduction in mass accompanied by remodeling of the contractile apparatus, which is associated with an 11-fold increase in myofibrillar protein synthesis by the end of the premolt period. Loss of a walking limb or claw causes a loss of mass

Kyle S. MacLea; Ali M. Abuhagr; Natalie L. Pitts; Joseph A. Covi; Brandon D. Bader; Ernest S. Chang; Donald L. Mykles

2012-01-01

52

Molting in workers of the Formosan subterranean termite Coptotermes formosanus.  

PubMed

The Formosan subterranean termite, Coptotermes formosanus, with its huge colonies, is a major urban pest in several southern states and Hawaii as well as in South Asia. Because of their cryptic nature (underground habitat) and very long life cycle, not much is known about molting in termite workers. In C. formosanus, the workers stop foraging and lose their gut fauna, respectively, approximately 10 and 5 days prior to ecdysis. In any given colony an average of 1.01% (range 0.6-1.8) of the workers were found to molt each day under laboratory conditions. Workers destined to molt become sluggish and their head capsules develop a mottled texture one day prior to ecdysis. Ecdysis was generally accomplished with the assistance of other workers, which also fed on the exuviae. Immediately after molting worker mandibles were light pink in color and became fully melanized approximately two days later. Gut fauna were acquired on the fourth day after molting. Flagellates were transferred as small encysted cells from other workers through proctodeal feeding. Juvenile hormone III titer ranged between 30-41 pg/mg bodyweight in all stages except in workers sampled 6 days prior to ecdysis. In these workers the titer was 80.5 pg/mg. The high juvenile hormones (JH) titer may also be involved in causing defaunation. Ecdysteroid titer increased from 2.1 pg/mg in non-molting workers to 359.5 and 332.4 pg/mg one and two days following defaunation, respectively. There was a second smaller peak two days prior to ecdysis. PMID:17904575

Raina, Ashok; Park, Yong Ihl; Gelman, Dale

2007-09-08

53

Potential of alfalfa as an alternative molt induction diet for laying hens: egg quality and consumer acceptability  

Microsoft Academic Search

Dietary molt induction to initiate additional egg laying cycles in commercial laying hen flocks is a wide spread practice in the United States. Feed deprivation is the most commonly used method but this practice has generated several concerns which has lead to research for viable alternative approaches. From a management standpoint a single ingredient molting diet consisting of high fiber-low

K. L. Landers; Z. R. Howard; C. L. Woodward; S. G. Birkhold; S. C. Ricke

2005-01-01

54

Cloning of a nitric oxide synthase from green shore crab, Carcinus maenas: A comparative study of the effects of eyestalk ablation on expression in the molting glands (Y-organs) of C. maenas, and blackback land crab, Gecarcinus lateralis  

Microsoft Academic Search

Molting in decapod crustaceans is regulated by ecdysteroids produced by a pair of Y-organs (YOs) located in the cephalothorax. YO ecdysteroidogenesis is suppressed by molt-inhibiting hormone (MIH), a neuropeptide produced in the X-organ of the eyestalk (ES) ganglia. MIH signaling may involve nitric oxide synthase (NOS) and NO-sensitive guanylyl cyclase (GC-I). A full-length cDNA encoding Carcinus maenas NOS (Cm-NOS; 3836

Audrey A. McDonald; Ernest S. Chang; Donald L. Mykles

2011-01-01

55

Crustacean endocrine toxicology: a review  

Microsoft Academic Search

Crustaceans are major constituents to aquatic ecosystems that provide a variety of ecological and economic services. Individual\\u000a crustacean species are adept at occupying diverse niches and their success, in part, stems from neuro-endocrine signaling\\u000a cascades that regulate physiology in response to environmental and internal cues. Peptide hormones are major signal transducers\\u000a in crustaceans. The crustacean hyperglycemic hormone family of peptides

Gerald A. LeBlanc

2007-01-01

56

Hemolymph ion composition and volume changes in the supralittoral isopod Ligia pallasii Brandt, during molt  

Microsoft Academic Search

We analyzed ion composition and volume of the hemolymph of Ligia pallasii in four different stages of the molt cycle using capillary electrophoresis and 3H-inulin. The main ions in the hemolymph were Na+, K+, Mg2+, Ca2+, and Cl?. The Ca2+concentration increased significantly during the molt by 47% from intermolt to intramolt and by 37% from intermolt to postmolt,\\u000a probably due

A. Ziegler; T. Grospietsch; T. H. Carefoot; J. P. Danko; M. Zimmer; I. Zerbst-Boroffka; S. C. Pennings

2000-01-01

57

Hormonally-regulated functions in crustaceans as biomarkers of environmental pollution.  

PubMed

The effects of organic and inorganic contaminants on functions regulated by hormones in crustaceans are being investigated with increasing frequency because several of these phenomena show promise of being useful biomarkers of environmental contamination. Heavy metals and organic compounds have been found in studies with crustaceans to negatively affect hormonally-regulated functions, specifically reproduction, molting, blood glucose level, and pigmentary effectors. Neurotransmitters, including 5-hydroxytryptamine and dopamine, have been identified as being involved in stimulating or inhibiting release of specific crustacean neurohormones such as the pigment-dispersing and pigment-concentrating ones involved in color changes. The effects of pollutants on at least some of these hormonally-regulated processes appear due at least in part to impacting release of a neurohormone, possibly by affecting release of the neurotransmitter that normally stimulates release of that particular neurohormone. PMID:9827049

Fingerman, M; Jackson, N C; Nagabhushanam, R

1998-10-01

58

Phenol oxidase is a necessary enzyme for the silkworm molting which is regulated by molting hormone.  

PubMed

Insect molting is an important developmental process of metamorphosis, which is initiated by molting hormone. The molting process includes the activation of dermal cells, epidermal cells separation, molting fluid secretion, the formation of new epidermis and old epidermis excoriation etc. Polyphenol oxidases (PPOs), dopa decarboxylase and acetyltransferase are necessary enzymes for this process. Traditionally, the phenol oxidase was considered as an enzyme for epidermal layer's tanning and melanization. This work suggested that polyphenol oxidases are one set of the key enzymes in molting, which closely related with the role of ecdysone in regulation of molting processes. The data showed that the expression peak of phenol oxidase in silkworm is higher during molting stage, and decreases after molting. The significant increase in the ecdysone levels of haemolymph was observed in the artificially fed silkworm larvae with ecdysone hormone. Consistently, the phenol oxidase expression was significantly elevated compared to the control. PPO1 RNAi induced phenol oxidase expression obviously declined in the silkworm larvae, and caused the pupae incomplete pupation. Overall, the results described that the phenol oxidase expression is regulated by the molting hormone, and is a necessary enzyme for the silkworm molting. PMID:23275200

Wang, Mei-xian; Lu, Yan; Cai, Zi-zheng; Liang, Shuang; Niu, Yan-shan; Miao, Yun-gen

2012-12-29

59

MGA AS AN ALTERNATIVE MOLTING METHOD FOR HENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inducing hens to molt increases egg quality, egg production and extends the productive life of hens. Molting is normally accomplished by feed withdrawal, which has received criticism, and alternatives described thus far have resulted in poor post-molt performance. The process of molting leads to ces...

60

Predicting crustacean zooplankton species richness  

Microsoft Academic Search

Data from 66 North American lakes were collected to construct a model for predicting the number of crustacean zooplankton species expected in a lake. The chosen lakes have a range from 4 m* to 80 x lo9 m2 surface area, range from ultra-oligotrophic to hypereutrophic, and have zooplankton species lists based on several years of observation. The number of crustacean

STANLEY DODSON

1992-01-01

61

Tissue-Specific Patterns and Steady-State Concentrations of Ecdysteroid Receptor and Retinoid-X-Receptor mRNA during the Molt Cycle of the Fiddler Crab, Uca pugilator  

Microsoft Academic Search

In the fiddler crab,Uca pugilator,we have investigated the temporal expression of receptors in various tissues using probes that encodeUcaecdysteroid receptor (UpEcR) and retinoid-X-receptor (UpRXR) gene homologs. During molt stages C4through D1–4,UpEcRandUpRXRtranscripts are expressed in regenerating limb buds, gills, eyestalks, hypodermis, hepatopancreas, muscle from nonregenerating walking legs, and the large cheliped. Some of these tissues have not previously been recognized as

Arthur C.-K. Chung; David S. Durica; Penny M. Hopkins

1998-01-01

62

Functional analysis of crustacean Hyperglycemic Hormone by in vivo assay with wild-type and mutant recombinant proteins  

Microsoft Academic Search

The neuro-endocrine X-organ sinus-gland complex regulates important crustacean physiological processes, such as growth, reproduction and molting. Its major products are the neuropeptides of the cHH\\/MIH\\/GIH family. Until now the structure–function relationships of these neuropeptides were established by sequence comparison. To study the functional relevance of conserved amino acid residues or peptide motifs, we generated point and deletion mutants of the

Romina Mettulio; Piero Giulio Giulianini; Enrico Antonio Ferrero; Simonetta Lorenzon; Paolo Edomi

2004-01-01

63

AGE AND SEX DIFFERENCES IN MOLT OF  

Microsoft Academic Search

Age and sex differences in the timing and pattern of feather molt in Montagu's harrier (Circus pygargus) was studied in 184 museum specimens and live birds collected throughout their breed- ing and wintering ranges. Molt in adults lasted 6-8 mo, starting in May-June in the breeding areas and finishing in January-February on the wintering grounds. Apparently, Montagu's harriers do not

S HARRIER

1996-01-01

64

When the seasons don't fit: speedy molt as a routine carry-over cost of reproduction.  

PubMed

The failure of animals to fit all life-cycle stages into an annual cycle could reduce the chances of successful breeding. In some cases, non-optimal strategies will be adopted in order to maintain the life-cycle within the scope of one year. We studied trade-offs made by a High Arctic migrant shorebird, the red knot Calidris canutus islandica, between reproduction and wing feather molt carried out in the non-breeding period in the Dutch Wadden Sea. We compared primary molt duration between birds undertaking the full migratory and breeding schedule with birds that forego breeding because they are young or are maintained in captivity. Molt duration was ca. 71 days in breeding adults, which was achieved by an accelerated feather replacement strategy. Second-year birds and captive adults took ca. 22% and 27% longer, respectively. Second-year birds start molt in late June, more than four weeks before captive adults, and almost seven weeks before adults that return from breeding in late July-August. Adults finish molt in October when steeply increasing thermostatic costs and reductions in food availability occur. Primary molt duration was longer in female than in male knots (all ages), which was accordance with the somewhat larger body size of females. Since fast growth leads to lower quality feathers, the speedy wing molt shown by Arctic-breeding birds may represent a time constraint that is an unavoidable and routine cost of reproduction. So far it was hypothesized that only birds over 1 kg would have difficulty fitting molt within a year. Here we show that in birds an order of magnitude smaller, temporal imperatives may impose the adoption of non-optimal life-cycle routines in the entire actively breeding population. PMID:23349758

Dietz, Maurine W; Rogers, Ken G; Piersma, Theunis

2013-01-17

65

Binding Proteins for an Ecdysone Metabolite in the Crustacean Hepatopancreas  

PubMed Central

When crustacean hepatopancreas is incubated in the presence of ?-3H]ecdysone of high specific activity and is then homogenized and centrifuged, a peak of protein-radioactivity is recovered after gel filtration of the 105,000 × g supernatant. Analysis of this peak by sucrose gradient centrifugation revealed the presence of two complexes of protein and labeled material (?11.5 S and 6.35 S). The same results were obtained in vivo. On standing at low ionic strength, the lighter component disappeared, suggesting that the heavier component is an aggregate of the lighter one. Chemical analysis of radioactive material in the complex revealed that it is not ?- or ?-ecdysone nor any previously described metabolite of the ecdysones. This new metabolite of ?-ecdysone is found mainly in the incubated hepatopancreas. Partial structures consistent with the analytical data are inferred for this metabolite. It is suggested that the metabolite may be active in the action of molting hormone.

Gorell, Thomas A.; Gilbert, Lawrence I.; Siddall, John B.

1972-01-01

66

Apoptosis-inducing effect of Jinke on Molt4 cells and its mechanism  

Microsoft Academic Search

Objective  To investigate the apoptosis-inducing effect of Jinke on Molt-4 cells and its possible mechanism.\\u000a \\u000a \\u000a \\u000a Methods  The Molt-4 cells were treated with different concentrations of Jinke and then cultured for necessary time. The Annexin-V \\/\\u000a PI method was used to detect the apoptosis rate. The cell cycle was analyzed by DNA content with flow cytometry. Double parameters\\u000a analysis of cyclins \\/ DNA

Zhenchuang Zhu; Yixin Tong; Yangping Yue; Yu Deng; Dongdong Yu; Wei Xiao; Xiaolan Li; Deding Tao; Junbo Hu; Jianping Gong

2008-01-01

67

Lunar-rhythmic molting in laboratory populations of the noble crayfish Astacus astacus (Crustacea, Astacidea): an experimental analysis.  

PubMed

Juvenile noble crayfish, Astacusastacus (Crustacea, Astacidea) in the second year of age were kept in the laboratory for a twelve-month period under continuing "summer conditions" (LD 16:8, 19°C). Molting processes in this population could be synchronized by artificial moonlight cycles. Peaks of exuviations occurred at "new moons". Males showed a slightly higher degree of synchronization than females. A phase-shift of the artificial lunar cycle in relation to the natural cycle resulted in a corresponding shift of the molting cycle. This clearly demonstrates that changes in the nocturnal light regime provide the primary external information for the lunar-monthly molting rhythm. There is a first indication that lunar photic stimuli do not act directly but as a zeitgeber which entrains an endogenous molting rhythm to the lunar cycle. Moreover, the results of the long-term experiments suggest that the hibernal resting period of A. astacus in the field (no molts between October and April) may also involve some endogenous programming. Continuing artificial summer conditions can delay but not completely suppress this resting period. The adaptive significance of the phenomena and how the findings may be applied to improve the management of crowded crayfish stocks are discussed. PMID:23840899

Franke, Robert; Hoerstgen-Schwark, Gabriele

2013-07-01

68

Induction of Molting in Horseshoe Crab Larvae by Polyhydroxy Steroids.  

National Technical Information Service (NTIS)

Molting in stage 1 horseshoe crab larvae, Limulus polyphemus, can be induced by polyhydroxy steriods that stimulate molting in insects. The effect of the injected steroids in shortening the intermolt period is dependent on dose and time of injection after...

T. C. Jegla J. D. Costlow

1969-01-01

69

Exploring neurogenesis in crustaceans.  

PubMed

Plasticity, learning and memory, and neurological disease are exciting topics for students. Discussion around these subjects often results in the consideration of the role of neurogenesis in development, or its involvement in a potential cure for some diseases. We have therefore designed a lab that allows students to experimentally examine how the rate of neurogenesis can be altered by environmental factors. Neuronal cell division in crayfish is identified with fluorescently-labeled BrdU and quantified using conventional or confocal microscopy. Recent studies indicate a conservation of mechanisms that control neurogenesis from insects and crustaceans to mammals. Yet the use of invertebrate models such as crayfish or lobsters has advantages over mammalian models. Invertebrate nervous systems have a simpler organization and larger, identifiable neurons - qualities that make such preparations easier for students to manage. This lab offers many opportunities for student designed experiments and discovery-oriented learning by exploring factors that regulate neurogenesis such as environment, hormones and light. This article illustrates our first experience with the lab, using an experiment designed by our students. We include ideas for expansion of this model and suggestions for avoiding potential pitfalls. It is written in the form of a scientific paper, reporting on a single student experiment, to aid as a teaching tool for future classes. PMID:23493254

Paul, Carol Ann; Goergen, Erin M; Beltz, Barbara S

2002-10-15

70

Chitinase activity in the epidermis of the fiddler crab, Uca pugilator, as an in vivo screen for molt-interfering xenobiotics.  

PubMed

We describe an in vivo screening assay that uses epidermal chitinase activity as the endpoint following a 7-day exposure of Uca pugilator to test chemicals. Chitinase, a chitinolytic enzyme, is the end product of endocrine cascades of a multi-hormonal system for control of crustacean molting. Wherever a molt-interfering agent adversely impacts the Y-organ-ecdysteroid receptor axis, the effect should be manifested by the activity of chitinase in the epidermis. Therefore, epidermal chitinase activity is an ideal endpoint for molt-interfering effects of xenobiotics. The validity of epidermal chitinase activity being used for such a purpose is supported by our finding that two injections of 20-hydroxyecdysone at 25 microg/g live weight induced a twofold increase in chitinase activity in the epidermis of U. pugilator. A total of nine chemicals were screened for molting hormone and anti-molting activities. o,p'-DDT was found to significantly inhibit epidermal chitinase activity while kepone and methoxychlor exhibited a tendency of inhibition of enzymatic activity. None of the remaining six chemicals, namely, p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), atrazine, tributyltin (TBT), methoprene, dieldrin and permethrin, had an effect on epidermal chitinase activity. PMID:15683831

Zou, Enmin; Bonvillain, Ryan

2004-12-01

71

Inhibitory effect of molt-inhibiting hormone on phantom expression in the Y-organ of the kuruma prawn, Marsupenaeus japonicus.  

PubMed

Molting in crustaceans is induced by ecdysteroids as in insects. The ecdysteroid titre in hemolymph is negatively regulated by molt-inhibiting hormone (MIH) that inhibits the secretion of ecdysteroids from the Y-organ, an ecdysteroid-producing gland of crustaceans, whereas little is known about the molecular mechanism of inhibition by MIH. Recently, the Halloween genes encoding cytochrome P450 monooxygenases were characterized as the steroidogenic enzymes in insects. To elucidate whether the ecdysteroidogenesis in the Y-organ is regulated by molt-inhibiting hormone (MIH), we analyzed the expression level of an orthologue of a member of the Halloween genes, phantom (Cyp306a1, phm), in the Y-organ of a decapod crustacean, Marsupenaeus japonicus. A cDNA encoding phm (Mj-phm) was cloned by degenerate PCR and 5'- and 3'-RACEs. The deduced amino acid sequence of Mj-phm showed about 40% identity to those of insect phm. The six motif sequences and the four substrate recognition sites were well conserved between Mj-PHM and other PHM. RT-PCR showed the specific expression of Mj-phm mRNA in the Y-organ. In addition, quantitative real-time PCR verified that the expression level of Mj-phm was significantly increased at the pre-molt stage and decreased after ecdysis. Furthermore, exposure of the Y-organ to MIH significantly decreased the Mj-phm expression level in vitro. These results indicate that the transcription of Mj-phm in the Y-organ may be regulated by the inhibitory mechanism of MIH of M. japonicus, which involves the consequent negative regulation of ecdysteroidogenesis at the transcriptional level. PMID:19802900

Asazuma, Hideaki; Nagata, Shinji; Nagasawa, Hiromichi

2009-12-01

72

Utilizing Different Ratios of Alfalfa and Layer Ration for Molt Induction and Performance in Commercial Laying Hens  

Microsoft Academic Search

Molting is a common practice used by the commercial egg industry to rejuvenate flocks for a second or third laying cycle. During this time the hens rest from production, and the reproductive organs are rejuvenated to increase production and quality during the next laying cycle.Althoughfeedwithdrawal(FW)isthemostpopular andeffective methodof moltinduction, ithascome under scrutiny due to food safety issues and animal welfare issues.

L. M. Donalson; W. K. Kim; C. L. Woodward; P. Herrera; L. F. Kubena; D. J. Nisbet; S. C. Ricke

73

Recent advances in crustacean genomics.  

PubMed

Crustaceans are a diverse and ancient group of arthropods that have long been studied as interesting model systems in biology, especially for understanding animal evolution and physiology and for environmentally relevant studies. Like many model systems, advances in DNA-sequencing methodologies have led to a large amount of genomics-related projects. The purpose of this article is to highlight the genome projects and functional genomics (transcriptomics) projects that are currently underway in crustacean biology. Specifically, we have surveyed the amount of publicly available DNA sequence data (both genomic and EST data) across all crustacean taxa for which a significant number of DNA sequences have been generated. Several ongoing projects are presented including the ecology of invasive species, thermal physiology, ion and water balance, ecology and evolutionary biology, and developmental biology. PMID:21669837

Stillman, Jonathon H; Colbourne, John K; Lee, Carol E; Patel, Nipam H; Phillips, Michelle R; Towle, David W; Eads, Brian D; Gelembuik, Greg W; Henry, Raymond P; Johnson, Eric A; Pfrender, Michael E; Terwilliger, Nora B

2008-10-30

74

Expression of recombinant eyestalk crustacean hyperglycemic hormone from the tropical land crab, Gecarcinus lateralis, that inhibits Y-organ ecdysteroidogenesis in vitro.  

PubMed

Crustacean hyperglycemic hormone (CHH) is a pleiotropic neuropeptide that regulates carbohydrate and lipid metabolism, molting, reproduction, and osmoregulation in decapod crustaceans. CHH elevates glucose levels in the hemolymph by stimulating glycogenolysis in target tissues. It also inhibits ecdysteroidogenesis in the molting gland, or Y-organ (YO), possibly as a response to environmental stress. CHH acts via binding to a membrane receptor guanylyl cyclase, which is expressed in most tissues, including the YO. Large amounts of biologically active neuropeptide are required to investigate the mechanism of CHH signaling in the YO. Consequently, the eyestalk ganglia CHH (EG-CHH) isoform was cloned into a yeast (Pichia pastoris) expression vector to express recombinant mature peptide (rEG-CHH) with or without a C-terminal c-Myc/polyhistidine tag. Yeast cultures with untagged or tagged rEG-CHH inhibited ecdysteroidogenesis in YOs from European green crab (Carcinus maenas) 36% (P < 0.002) and 51% (P < 0.006), respectively. Purified tagged EG-CHH inhibited YO ecdysteroidogenesis 32% (P < 0.002), but lacked hyperglycemic activity in vivo. This is the first report of recombinant EG-CHH inhibiting YO ecdysteroidogenesis. The data suggest that the tagged recombinant peptide can be used to elucidate the CHH signaling pathway in the crustacean molting gland. PMID:18595002

Zarubin, Tyler P; Chang, Ernest S; Mykles, Donald L

2008-07-02

75

The L3 to L4 molt of Brugia malayi: real time visualization by video microscopy.  

PubMed

Brugia malayi and other filarial parasites have been studied in great detail, especially in the context of human disease. In common with other nematodes, these organisms molt 4 times in their life cycles, but details of this process have not been described. We have recently developed an in vitro culture system that supports the L3 to L4 molt at high efficiency. This has permitted us to visualize, for the first time, details of this molt using real-time video microscopy. Molting is preceded by a phase of altered motility during which the larva exhibits contractile, coiling movements. The earliest evidence of ecdysis is a clearing at one end, more frequently caudal, caused by the larva retracting from that end. A cleavage develops in the cuticle near the head end, forming a rostral cap, which is continuous with the pharyngeal cuticle. Simultaneously, it retracts out of the cuticle using coiling and writhing movements. This process takes 5 to 10 min. Finally, it retracts out of the cap and extrudes the pharyngeal cuticle. Detachment of the pharyngeal cuticle is the final event in the process and continues up to an hour after the rest of the cuticle has been shed. PMID:16419744

Ramesh, Manish; McGuiness, Carol; Rajan, T V

2005-10-01

76

Crustacean hyperglycemic hormone (CHH) neuropeptidesfamily: Functions, titer, and binding to target tissues.  

PubMed

The removal of the eyestalk (s) induces molting and reproduction promoted the presence of regulatory substances in the eyestalk (ES), particularly medulla terminalis X-organ and the sinus gland (MTXO-SG). The PCR-based cloning strategies have allowed for isolating a great number of cDNAs sequences of crustacean hyperglycemic hormone (CHH) neuropeptides family from the eyestalk and non-eyestalk tissues, e.g., pericardial organs and fore- and hindguts. However, the translated corresponding neuropeptides in these tissues, their circulating concentrations, the mode of actions, and specific physiological functions have not been well described. The profiles of CHH neuropeptides present in the MTXO-SG may differ among decapod crustacean species, but they can be largely divided into two sub-groups on the basis of structural homology: (1) CHH and (2) molt-inhibiting hormone (MIH)/mandibular organ-inhibiting hormone (MOIH)/vitellogenesis/gonad-inhibiting hormone (V/GIH). CHH typically elevating the level of circulating glucose from animals under stressful conditions (hyper- and hypothermia, hypoxia, and low salinity) has multiple target tissues and functions such as ecdysteroidogenesis, osmoregulation, and vitellogenesis. Recently, MIH, known for exclusively suppressing ecdysteroidogenesis in Y-organs, is also reported to have an additional role in vitellogenesis of adult female crustacean species, suggesting that some CHH neuropeptides may acquire an extra regulatory role in reproduction at adult stage. This paper reviews the regulatory roles of CHH and MIH at the levels of specific functions, temporal and spatial expression, titers, their binding sites on the target tissues, and second messengers from two crab species: the blue crab, Callinectes sapidus, and the European green crab, Carcinus maenas. It further discusses the diverse regulatory roles of these neuropeptides and the functional plasticity of these neuropeptides in regard to life stage and species-specific physiology. PMID:20026335

Chung, J Sook; Zmora, N; Katayama, H; Tsutsui, N

2009-12-22

77

Hemolymph proteins in marine crustaceans  

PubMed Central

This study is done with the aim to bring together the various antimicrobial peptides that are present in the crustacean hemolymph and their sources along with its characteristics. Invertebrates lack immune systems that involve antigen-antibody reactions and do not have an immune memory, therefore most invertebrate species show no evidence of acquired immunity. Crustaceans possess an open circulatory system, where nutrients, oxygen, hormones, and cells are distributed in the hemolymph. They lack adaptive immune system and rely exclusively on their innate immune mechanisms that include both cellular and humoral responses. Antimicrobial peptides and proteins form an important means of host defense in eukaryotes. In addition to their role as endogenous antibiotics, antimicrobial peptides have functions in inflammation, wound repair and regulation of the adaptive immune system. Over the past several years, many antimicrobial peptides have been found and characterized in crabs.

Fredrick, W Sylvester; Ravichandran, S

2012-01-01

78

Identification of Crustacean Sex Pheromones  

Microsoft Academic Search

\\u000a Odor and fragrances can carry information about an organism and have long been suggested as vital mechanisms that affect or\\u000a control animal behavior. The use of such chemical signals is widespread in the aquatic environment, and crustaceans such as\\u000a lobsters, shrimps, crabs, barnacles, and crayfish are known to utilize odor for predator–prey interactions, mating, establishing\\u000a of dominance or social hierarchies

Joerg D. Hardege; John A. Terschak

79

Cellular Pharmacology of Cyclopentenyl Cytosine in Molt4 Lymphoblasts  

Microsoft Academic Search

The toxicity, uptake, and metabolism of the oncolytic nucleoside cyclopentenyl cytosine (CPEC) have been examined in the Molt-4 line of human lymphoblasts. This compound is known to be converted to its 5'- triphosphate, which inhibits CTP synthetase and depletes the pools of cytidine nucleotides. In the Molt-4 system, the concentration of drug reducing proliferation by 50% in a 24-h incubation

Harry Ford; David A. Cooney; Gurpreet S. Ahluwalia; Michael E. Rommel; LeRoi Hicks; Kathryn A. Dobyns; Joseph E. Tomaszewski; David G. Johns

80

Movements of flightless long-tailed ducks during wing molt  

USGS Publications Warehouse

We examined the movements of flightless Long-tailed Ducks (Clangula hyemalis) during the wing molt in the near-shore lagoons of the Beaufort Sea in Alaska. Estimates of site fidelity during the 21-day flightless period ranged from 1-100%, with considerable variation among locations and within locations among years. There was no effect of low-level experimental disturbance or an underwater seismic survey on site fidelity of molting Long-tailed Ducks. Birds molting along a relatively consistent habitat gradient were more likely to move than those molting in a fragmented habitat. While flocks of birds are consistently observed in the same locations, these data suggest considerable turnover within these aggregations. These results, in conjunction with other studies, suggest that forage is relatively uniformly distributed within lagoons. We conclude that habitat selection by molting Long-tailed Ducks is likely influenced by protection from wind and associated waves.

Flint, P. L.; Lacroix, D. L.; Reed, J. A.; Lanctot, R. B.

2004-01-01

81

Crustacean primary cell culture: A technical approach  

Microsoft Academic Search

Crustacean cell culture has gained attention as a potent model to assist in the development of diagnostic reagents and probes for use in the shrimp, crayfish and lobster industries. The availability of such cellular tools is especially important to industries which use intensive aquaculture methods and thus have increased risk of disease problems. Indeed, crustacean cell cultures offer potential for

Jean-Yves Toullec

1999-01-01

82

Comparison of crustacean and insect mechanoreceptive setae  

Microsoft Academic Search

Mechanosensitive cells of crustacean setae show important cytological differences compared with those of insects. The mechanosensitive cells in arthropod setae can be classified in 2 groups, which are structurally and functionally different. The typical mechanosensitive cells of insect setae show a tubular body at the tip of their dendrites, whereas mechanosensitive cells of aquatic crustaceans never show such a structure

Yves Crouau

1997-01-01

83

ENVIRONMENT, HEALTH, AND BEHAVIOR Comparison of Zinc Acetate and Propionate Addition on Gastrointestinal Tract Fermentation and Susceptibility of Laying Hens to Salmonella enteritidis During Forced Molt  

Microsoft Academic Search

Feed deprivation is the most common method used to induce molting and stimulate multiple egg-laying cycles in laying hens for commercial egg pro- duction. Unfortunately, an increased risk of Salmonella enteritidis (SE) colonization may result from the use of this method. Methods to stimulate multiple egg-laying cycles without increasing the risk of SE are needed. In each of 3 experiments,

R. W. Moore; S. Y. Park; L. F. Kubena; J. A. Byrd; J. L. McReynolds; M. R. Burnham; M. E. Hume; S. G. Birkhold; D. J. Nisbet; S. C. Ricke

84

MOLT PATTERNS AND WEIGHT CHANGES OF THE llMERICAN WOODCOCK  

Microsoft Academic Search

EW data are available on the timing and extent of molts in the American Woodcock (Philohela minor). Pettingill (1936) described the plumages, pterylae, and certain aspects of the molt sequence. Martin (1964) studied flight feather molt and developed a rapid aging technique, while Sheldon (1967) provided molt data for 13 birds. Numerous workers have reported weights of male and female

WILLIAM B. KROHN

85

Primary feather molt of adult mourning doves in North and South Carolina  

USGS Publications Warehouse

Examination of 8,141 adult mourning doves (Zenaida macroura) in North and South Carolina revealed that substantial numbers complete primary feather molt in September. Adult mourning doves shed primaries at the rate of 1 per 14 days. No difference was found in this rate between sexes or among years, 1969-74. The initiation of molt differed from year to year, and female molt always preceded male molt. Available data show that southern doves complete primary molt a month earlier than northern doves. Therefore, age based on primary molt can be biased upward if all molt-complete wings from southern hunting samples are considered immature.

Haas, G.H.; Amend, S.R.

1979-01-01

86

Growth and molting in epizoic pedunculate barnacles genus Octolasmis (Crustacea: Thecostraca: Cirripedia: Thoracica).  

PubMed

Scanning electron microscopy, light microscopy, and histology were used to study growth in species of the pedunculate barnacle genus Octolasmis (O. angulata, O. cor, O. californiana, O. mülleri). These species are epizoic in the gill chamber of portunid crabs and have highly reduced capitular shell plates, with large areas of general cuticle in between. The external integument grows by means of a system of narrow growth zones, one encircling the peduncle and a Y-shaped system on either side of the capitulum. Growth is by a regular series of molts, but shedding of old cuticle and production of new layers is entirely restricted to the growth zones. Just prior to ecdysis, the new cuticle lies in a highly folded fashion beneath the old cuticle that is about to be shed. At ecdysis, the old cuticle breaks along the margins of the growth zones and the resulting scars remain as a system of "ecdysial lines" along either side of the zone. Once exposed after ecdysis, the new cuticle remains as a part of the permanent external integument. The growth zones divide the externa into five cuticular areas, two on the peduncle and three on the capitulum. The calcareous shell plates (carina, paired scuta, and, when present, paired terga) all lie within the capitular regions and the ecdysial lines pass across, not around, these mineralized areas. The number, relative spacing, and topology of the ecdysial lines form a record of the growth history of the specimen. These and other growth patterns demonstrate that size increase is due to the formation of new cuticle by molting in the growth zones, while expansion of the shell plates by mineralization follows only after production of the new cuticle. Thus, although specialized, growth in Octolasmis still complies with the general crustacean model, complicated only by the mineralization of parts of the capitular cuticle into shell plates. The results are compared with the very scarce information on molting in other barnacles. We argue that at least the circular peduncular growth zone is omnipresent in the Cirripedia Thoracica. PMID:15108155

Blomsterberg, Mikkel; Glenner, Henrik; Høeg, Jens T

2004-05-01

87

Crustacean hyperglycaemic hormone in the nervous system of the primitive crustacean species Daphnia magna and Artemia salina (Crustacea: Branchiopoda)  

Microsoft Academic Search

Crustacean hyperglycaemic hormone-immunoreactive neuronal systems are detected in the central and peripheral nervous systems of two entomostracan crustaceans, Daphnia magna and Artemia salina, by immunocytochemistry using specific antisera against crustacean hyperglycaemic hormones of the decapod crustaceans Orconectes limosus and Carcinus maenas. In D. magna, four small putative interneurones are detected in the brain. In the thorax, ten bipolar peripheral neurones

Qian Zhang; Rainer Keller; Heinrich Dircksen

1997-01-01

88

Trolox Inhibits Apoptosis in Irradiated MOLT-4 Lymphocytes.  

National Technical Information Service (NTIS)

MOLT-4 cells, a human lymphocytic leukemia line, undergo apoptosis in response to a variety of stimuli, including exposure to ionizing radiation. Very little is known of the molecular mechanisms by which radiation induces apoptosis. Morphology changes and...

D. E. McClain J. F. Kalinich N. Ramakrishnan

1995-01-01

89

Molt patterns, age, and sex criteria for selected highland Costa ...  

Treesearch

Treesearch Home ... Description: Demographic studies within temperate latitudes often use molt and ... of bird ecology in coffee plantations and forest habitats in the Cordillera de Tilarán, Costa Rica (winter and spring of 2006/07 and 2007/08).

90

Nuclear hormone receptor CHR3 is a critical regulator of all four larval molts of the nematode Caenorhabditis elegans  

PubMed Central

CHR3 (nhr-23, NF1F4), the homologue of Drosophila DHR3 and mammalian ROR/RZR/RevErbA nuclear hormone receptors, is important for proper epidermal development and molting in the nematode Caenorhabditis elegans. Disruption of CHR3 (nhr-23) function leads to developmental changes, including incomplete molting and a short, fat (dumpy) phenotype. Here, we studied the role of CHR3 during larval development by using expression assays and RNA-mediated interference. We show that the levels of expression of CHR3 (nhr-23) cycle during larval development and reduction of CHR3 function during each intermolt period result in defects at all subsequent molts. Assaying candidate gene expression in populations of animals treated with CHR3 (nhr-23) RNA-mediated interference has identified dpy-7 as a potential gene acting downstream of CHR3. These results define CHR3 as a critical regulator of all C. elegans molts and begin to define the molecular pathway for its function.

Kostrouchova, Marta; Krause, Michael; Kostrouch, Zdenek; Rall, Joseph Edward

2001-01-01

91

Alternative procedures for molt induction: practical aspects.  

PubMed

Shortening daylight (to 10.5 to 11 h/d) slightly reduced the rest period (the interval between last egg and first clutch), whereas feeding a low-protein diet during the 22-d period following 8 d of feed withdrawal (FW) (recovery period) markedly extended it. Feed withdrawal accompanied by a short-daylight regime and a long recovery period led to the best postmolt production. However, production per hen housed during the whole experimental period was only slightly increased. Thus, a long rest period may mask the positive effects of short daylight and recovery diet. At least 140 to 170 d were needed to enable the molted hens to compensate for the loss of eggs during the rest period. Therefore, under certain economic conditions, rearing of nonmolting hens for 640 to 700 d should be an economic consideration. Ten days of feeding of a diet containing 0.06% nicarbazin (NICR) arrested egg production and caused a 22-d rest period but not a typical molt. Few variables of production or shell quality were improved by NICR but to a lesser extent than by FW or Zn feeding. Five days of feeding on a high-Zn diet (20 g Zn/kg; HZn) improved postmolt performances similarly to FW. Ten days of feeding on a modest-Zn (2.8 g Zn/kg), low-Ca, and low-P diet (Zn-CaP) affected postmolt performances inconsistently. In one out of two trials (trial 2), the effects of Zn-CaP were similar to those of FW or HZn; in the other (trial 3), the effects were less pronounced, more time was required for egg arrest, and more eggs were laid occasionally during the rest period. In trial 2, only the Zn-CaP diet was accompanied by short daylight. In both trials, feed intake during the induction period was only slightly reduced. Zn feeding increased the yolk Zn content slightly in eggs laid during the induction period and at the onset of production. In trial 2, only Zn-CaP markedly increased yolk Zn of eggs laid during the first 5 d of production. PMID:12710472

Bar, A; Razaphkovsky, V; Shinder, D; Vax, E

2003-04-01

92

ALTERATIONS IN THE GROWTH, REPRODUCTION AND ENERGY METABOLISM OF ESTUARINE CRUSTACEANS AS INDICATORS OF POLLUTANT STRESS  

EPA Science Inventory

An estuarine mysid (Mysidopsis bahia) has been identified as one of the most sensitive members of the estuarine community to pollutant stress (for a review see Nimmo and Hamaker, 1982). n the majority of life-cycle toxicity tests using this planktonic estuarine crustacean, sublet...

93

Inverse Demographic Analysis of Compensatory Responses to Resource Limitation in the Mysid Crustacean Americamysis bahia  

EPA Science Inventory

Most observations of stressor effects on marine crustaceans are made on individuals or even-aged cohorts. Results of these studies are difficult to translate into ecological predictions, either because life cycle models are incomplete, or because stressor effects on mixed age po...

94

Complex Population Responses to Food Resources in the Marine Crustacean Americamysis Bahia  

EPA Science Inventory

Most observations of stressor effects on marine crustaceans are made on individuals or even-aged cohorts. Results of these studies are difficult to translate into ecological predictions, either because life cycle models are incomplete, or because stressor effects on mixed age po...

95

Changes in Timing, Duration, and Symmetry of Molt of Hawaiian Forest Birds  

PubMed Central

Food limitation greatly affects bird breeding performance, but the effect of nutritive stress on molt has barely been investigated outside of laboratory settings. Here we show changes in molting patterns for an entire native Hawaiian bird community at 1650–1900 m elevation on the Island of Hawaii between 1989–1999 and 2000–2006, associated with severe food limitation throughout the year beginning in 2000. Young birds and adults of all species took longer to complete their molt, including months never or rarely used during the 1989–1999 decade. These included the cold winter months and even the early months of the following breeding season. In addition, more adults of most species initiated their molt one to two months earlier, during the breeding season. Suspended molt, indicated by birds temporarily not molting primary flight feathers during the months of peak primary molt, increased in prevalence. Food limitation reached the point where individuals of all species had asymmetric molt, with different primary flight feathers molted on each wing. These multiple changes in molt, unprecedented in birds, had survival consequences. Adult birds captured during January to March, 2000–2004, had lower survival in four of five species with little effect of extended molt. Extended molt may be adaptive for a nutrient stressed bird to survive warm temperatures but not cool winter temperatures that may obliterate the energy savings. The changing molt of Hawaiian birds has many implications for conservation and for understanding life history aspects of molt of tropical birds.

Freed, Leonard A.; Cann, Rebecca L.

2012-01-01

96

Role of calcium-dependent proteinase in molt-induced claw muscle atrophy  

SciTech Connect

The claw closer muscle of the Bermuda land crab Gecarcinus lateralis undergoes a sequential atrophy and restoration during each intermolt cycle. Muscle protein decreases 40% during proecdysis and is restored following ecdysis. Amino acid incorporation into protein of postecdysial muscle is five times greater than that in anecdysial muscle. Since the rates of protein synthesis in anecdysial and proecdysial muscle are the same it appears that proecdysial muscle atrophy is caused primarily by an increase in protein degradation. A calcium-dependent proteinase (CDP) active at neutral pH has been implicated in the nonlysosomal hydrolysis of myofibrillar proteins. We have examined the role of a CDP in atrophy of the claw closer muscle. The many similarities between crustacean and vertebrate CDPs have established this crustacean system as a simple and convenient model for the role of Ca/sup 2 +/-dependent proteolysis in myofibrillar protein turnover and its manifestation in the structure of the sarcomere. 16 references, 8 figures. (ACR)

Mykles, D.L.; Skinner, D.M.

1984-01-01

97

Expression of biologically active crustacean hyperglycemic hormone (CHH) of Penaeus monodon in Pichia pastoris.  

PubMed

Crustacean hyperglycemic hormone (CHH), molt-inhibiting hormone (MIH), and gonad-inhibiting hormone (GIH) are members of a major peptide family produced from the X-organ sinus gland complex in the eyestalk of crustaceans. This peptide family plays important roles in controlling several physiologic processes such as regulation of growth and reproduction. In this study the complementary DNA encoding a peptide related to the CHH/MIH/GIH family (so-called Pem-CMG) of the black tiger prawn Penaeus monodon was successfully expressed in the yeast Pichia pastoris under the control of the AOX1 promoter. The recombinant Pem-CMG was secreted into the culture medium using the alpha-factor signal sequence; of Saccharomyces cerevisiae without the Glu-Ala-Glu-Ala spacer peptide. The amino terminus of the recombinant Pem-CMG was correctly processed as evidenced by amino-terminal peptide sequencing. The recombinant Pem-CMG was purified by reverse-phase high-performance liquid chromotography and used in a biological assay for CHH activity. The final yield of the recombinant Pem-CMG after purification was 260 micro g/L of the culture medium. Both crude and purified recombinant Pem-CMG produced from P. pastoris showed the ability to elevate the glucose level in the hemolymph of eyestalk-ablated P. monodon, which demonstrates that Pem-CMG peptide functions as hyperglycemic hormone in P. monodon. PMID:14719165

Treerattrakool, Supattra; Udomkit, Apinunt; Eurwilaichitr, Lily; Sonthayanon, Burachai; Panyim, Sakol

98

Topographical and typological comparison of the rodlike setae of ambulatory dactylopodites in decapod crustaceans  

SciTech Connect

The arrangement and external morphology of the rodlike setae and associated structures located on the dactylopodites of the walking legs of six species of decapod crustaceans are compared. The dactyls of littoral species, represented by the rock crab, Cancer antennarius, and the spiny lobster, Panulirus interruptus, have dense tufts and bands of rodlike setae, as is typical of many decapods, and additionally only a few small plumed setae. The arrangement of setae on the dactyls of the recently discovered Galapagos vent crab. Bythograea thermydron, closely resembles that of C. antennarius. Rodlike and long plumed setae occur in about equal numbers on the dactyls of the pelagic anomuran, Pleuroncodes planipes. The dactyls having the fewest rodlike setae are those of the terrestrial hermit crab, Coenobita perlatus, and those of the kelp crab, Pugettia producta, where flat setae typical of Majidae have replace most rodlike setae. The presence and structures of the terminal pores in rodlike setae vary intra- and interspecifically, possibly as a function of molt stage. Variations in some features of rodlike setae, such as tip acuity and presence of microsetae and surface sculpting, appear to be related to development. Serrated setae occur on the dactyls of megalopal P. producta but not in later stages. The topography and typolgy of setae located on the ambulatory dactyls of decapod crustaceans are considered in light of recent interest in using seta characteristics to determine the sensory functions of sensilla and to clarify the phylogeny of arthropod groups.

Hamilton, K.A.

1983-01-01

99

Mineral deposition in bacteria-filled and bacteria-free calcium bodies in the crustacean Hyloniscus riparius (Isopoda: Oniscidea).  

PubMed

Crustacean calcium bodies are epithelial sacs which contain a mineralized matrix. The objectives of this study were to describe the microscopic anatomy of calcium bodies in the terrestrial isopod Hyloniscus riparius and to establish whether they undergo molt-related structural changes. We performed 3D reconstruction of the calcium bodies from paraffin sections and analyzed their structure with light and electron microscopy. In addition, we analyzed the chemical composition of their mineralized matrices with micro-Raman spectroscopy. Two pairs of these organs are present in H. riparius. One pair is filled with bacteria while the other pair is not. In non-molting animals, the bacteria-filled calcium bodies contain apatite crystals and the bacteria-free calcium bodies enclose CaCO3-containing concretions with little organic matrix. During preparation for molt, an additional matrix layer is deposited in both pairs of calcium bodies. In the bacteria-filled calcium bodies it contains a mixture of calcium carbonate and calcium phosphate, whereas only calcium carbonate is present in bacteria-free calcium bodies. After ecdysis, all mineral components in bacteria-free calcium bodies and the additional matrix layer in bacteria-filled calcium bodies are completely resorbed. During calcium resorption, the apical surface of the calcium body epithelium is deeply folded and electron dense granules are present in spaces between epithelial cells. Our results indicate that the presence of bacteria might be linked to calcium phosphate mineralization. Calcium bodies likely provide a source of calcium and potentially phosphate for the mineralization of the new cuticle after molt. Unlike other terrestrial isopods, H. riparius does not form sternal CaCO3 deposits and the bacteria-free calcium bodies might functionally replace them in this species. PMID:23554963

Vittori, Miloš; Rozman, Alenka; Grdadolnik, Jože; Novak, Urban; Štrus, Jasna

2013-03-12

100

A molt timer is involved in the metamorphic molt in Manduca sexta larvae.  

PubMed

Manduca sexta larvae are a model for growth control in insects, particularly for the demonstration of critical weight, a threshold weight that the larva must surpass before it can enter metamorphosis on a normal schedule, and the inhibitory action of juvenile hormone on this checkpoint. We examined the effects of nutrition on allatectomized (CAX) larvae that lack juvenile hormone to impose the critical weight checkpoint. Normal larvae respond to prolonged starvation at the start of the last larval stage, by extending their subsequent feeding period to ensure that they begin metamorphosis above critical weight. CAX larvae, by contrast, show no homeostatic adjustment to starvation but start metamorphosis 4 d after feeding onset, regardless of larval size or the state of development of their imaginal discs. By feeding starved CAX larvae for various durations, we found that feeding for only 12-24 h was sufficient to result in metamorphosis on day 4, regardless of further feeding or body size. Manipulation of diet composition showed that protein was the critical macronutrient to initiate this timing. This constant period between the start of feeding and the onset of metamorphosis suggests that larvae possess a molt timer that establishes a minimal time to metamorphosis. Ligation experiments indicate that a portion of the timing may occur in the prothoracic glands. This positive system that promotes molting and the negative control via the critical weight checkpoint provide antagonistic pathways that evolution can modify to adapt growth to the ecological needs of different insects. PMID:23852731

Suzuki, Yuichiro; Koyama, Takashi; Hiruma, Kiyoshi; Riddiford, Lynn M; Truman, James W

2013-07-12

101

Selenoprotein TRXR-1 and GSR-1 are essential for removal of old cuticle during molting in Caenorhabditis elegans  

PubMed Central

Selenoproteins, in particular thioredoxin reductase, have been implicated in countering oxidative damage occurring during aging but the molecular functions of these proteins have not been extensively investigated in different animal models. Here we demonstrate that TRXR-1 thioredoxin reductase, the sole selenoprotein in Caenorhabditis elegans, does not protect against acute oxidative stress but functions instead together with GSR-1 glutathione reductase to promote the removal of old cuticle during molting. We show that the oxidation state of disulfide groups in the cuticle is tightly regulated during the molting cycle, and that when trxr-1 and gsr-1 function is reduced, disulfide groups in the cuticle remain oxidized. A selenocysteine-to-cysteine TRXR-1 mutant fails to rescue molting defects. Furthermore, worms lacking SELB-1, the C. elegans homolog of Escherichia coli SelB or mammalian EFsec, a translation elongation factor known to be specific for selenocysteine in E. coli, fail to incorporate selenocysteine, and display the same phenotype as those lacking trxr-1. Thus, TRXR-1 function in the reduction of old cuticle is strictly selenocysteine dependent in the nematode. Exogenously supplied reduced glutathione reduces disulfide groups in the cuticle and induces apolysis, the separation of old and new cuticle, strongly suggesting that molting involves the regulated reduction of cuticle components driven by TRXR-1 and GSR-1. Using dauer larvae, we demonstrate that aged worms have a decreased capacity to molt, and decreased expression of GSR-1. Together, our results establish a function for the selenoprotein TRXR-1 and GSR-1 in the removal of old cuticle from the surface of epidermal cells.

Stenvall, Jorgen; Fierro-Gonzalez, Juan Carlos; Swoboda, Peter; Saamarthy, Karunakar; Cheng, Qing; Cacho-Valadez, Briseida; Arner, Elias S. J.; Persson, Olof P.; Miranda-Vizuete, Antonio; Tuck, Simon

2011-01-01

102

CpG oligodeoxynucleotide 5mer-induced apoptosis in MOLT-4 leukaemia cells does not require caspase 3 or new protein synthesis  

PubMed Central

We have established that CpG oligodeoxynucleotide 5mers, of sequence type CGNNN (N = A, G, C or T), rapidly induce apoptosis/cell cycle arrest in human leukaemia lines. The 5?-CpG is obligatory for these effects. Induction of apoptosis in MOLT-4 cells did not require new protein synthesis and was insensitive to the caspase 3 inhibitor, Ac-DEVD-CHO, although the latter abrogated DNA laddering, phosphatidylserine externalization and collapse of the mitochondrial transmembrane potential. A subline of MOLT-4 cells, MOLT-4CpGR, was selected for acquired resistance to CpG 5mers. Differences in gene expression between MOLT-4 and MOLT-4CpGR cells were identified following three independent reciprocal cDNA subtractions, consensus selection and virtual cloning through targeted display. Several known genes were implicated in the action of or resistance to CpG oligodeoxynucleotide 5mers. Their protein products listed below immediately suggest cell signalling pathways/processes worthy of further investigation in elucidating the mechanism of CpG 5mer activity: caspase 2, the transcription factors Atf4, Hic, HoxB3 and Rqcd1, the splicing factors Rbmx, Sfrs5 and Sfrs7, the DNA replication factors Mcm5 and Brd4, phosphoinositide-3-kinase, annexin A1, mucosa-associated lymphoid tissue lymphoma translocation 1 and three enzymes involved in protein ubiquitylation, Siah1, Gsa7 and Nin283.

Tidd, David M.; Broughton, Caroline M.; Clark, Richard E.

2003-01-01

103

Hormonal treatment and flight feather molt in immature Sandhill Cranes  

USGS Publications Warehouse

Molt, the production of a new generation of feathers, is a poorly understood physiological phenomenon in nondomestic birds. Often in large birds like geese, flight is restricted by clipping the primary remiges on 1 wing and flight is restored after the molt when the primaries are replaced. A similar technique would be desirable for use with cranes conditioned for release to the native habitat. However, immature sandhill cranes (Grus canadensis) did not appear to replace their primaries annually; therefore, we studied their flight feather molt (from 4 months to 3.5 years of age) and attempted to influence molting. Under natural conditions tail feathers (rectrices) were replaced annually and all secondaries replaced in 2.5-year-old birds. However, replacement of primaries in immature sandhill cranes appears to be a gradual process beginning the 2nd year; about 33% of the original primaries (present at 10 months of age) persisted in the 3.5-year-oId birds. Pulling out the primaries of immature sandhill cranes induces the growth of new primaries, as is true of many other birds. However, the new primaries were incapable of supporting flight, fell out repeatedly, and those that remained were often deformed. Pulling the primaries, under the influence of tranquilizers and anesthetics to relax the feather papillae, also did not induce normal growth of the replacement primaries. Progesterone (including excessively high doses), thyroxine, and follicle stimulating hormone, although effective in inducing feather replacement in domestic poultry, had no effect on crane molt.

Gee, G.F.

1982-01-01

104

The Feasibility of Closed System Mariculture: Preliminary Experiments with Crab Molting.  

National Technical Information Service (NTIS)

A recirculation system for inducing shedding in the blue crab, Callinectes sapidus Rathbun, and preliminary experiments on crab molting are described. The most important result was the inducement of out of season molting (January-March) in the Delaware Ba...

R. R. Winget D. Maurer L. Anderson

1973-01-01

105

VITELLOGENISIS AND IT'S ENDOCRINE CONTROL IN DECAPOD CRUSTACEANS  

EPA Science Inventory

Vitellogenesis, the production of vitellin (major yolk protein), is controlled in decapod crustaceans by several hormones. With increasing efforts world-wide to successfully culture economically important crustaceans, such as shrimp, there is growing interest in attaining a bette...

106

A review on development of novel strategies for controlling Salmonella Enteritidis colonization in laying hens: fiber-based molt diets.  

PubMed

Limiting Salmonella Enteritidis from table eggs can involve intervention approaches at several levels of the production cycle, beginning at the hatchery and ending at the processing or table egg production facilities. Likewise, interventions that limit Salmonella Enteritidis dissemination can be implemented at various stages during the life cycle of infection of Salmonella in the laying hen. However, achieving complete elimination of Salmonella infestation in egg products has remained elusive. There is a multitude of reasons for this, including adaptability of the organism, virulence properties, and persistence. Likewise, environmental factors in the layer house such as transmission routes, reservoirs, and feed sources can influence the exposure of susceptible laying hens to Salmonella Enteritidis. Consequently, successful applications of control measures depend not only on the timing of when they are applied but also on effective surveillance to detect frequency and level of infection of Salmonella. Several studies demonstrated that molt induction by feed withdrawal altered the immune system and the gastrointestinal tract of hens, making them susceptible to Salmonella Enteritidis colonization of the gastrointestinal tract. To alleviate this, the development of alternative methods to induce a molt became necessary. The use of several fiber-containing diets was shown to effectively induce a molt with alfalfa-based diets being the most extensively studied. Further reduction of Salmonella Enteritidis levels in eggs will probably require application of multiple interventions at several steps during egg production and processing as well as a better understanding of the mechanisms used by Salmonella Enteritidis to persist in laying flocks. PMID:23300320

Ricke, S C; Dunkley, C S; Durant, J A

2013-02-01

107

Identification and developmental expression of mRNAs encoding crustacean cardioactive peptide (CCAP) in decapod crustaceans  

Microsoft Academic Search

Full-length cDNAs encoding crustacean cardioactive peptide (CCAP) were isolated from several decapod (brachyuran and astacuran) crustaceans: the blue crab Callinectes sapidus, green shore crab Carcinus maenas, European lobster Homarus gamarus and calico crayfish Orconectes immunis. The cDNAs encode open reading frames of 143 (brachyurans) and 139-140 (astacurans) amino acids. Apart from the predicted signal peptides (30-32 amino acids), the conceptually

J. S. Chung; D. C. Wilcockson; N. Zmora; Y. Zohar; H. Dircksen; S. G. Webster

2006-01-01

108

Trolox inhibits apoptosis in irradiated MOLT4 lymphocytes  

Microsoft Academic Search

MOLT-4 cells, a human lymphocytic leukemia line, undergo apoptosis in response to a variety of stimuli, including exposure to ionizing radiation. Very little is known of the molecular mechanisms by which radiation induces apoptosis. Morphology changes and chromatin cleavage at in- ternucleosomal sites accompany apoptosis in these cells. We found that trolox, a water-soluble deriva- tive of vitamin E that

JOHN F. KALINICH; NARAYANI RAMAKRISHNAN

109

Behavior of laying hens on alfalfa crumble molt diets  

Technology Transfer Automated Retrieval System (TEKTRAN)

Induced molting by feed withdrawal has been a common practice in the commercial layer industry and usually involves the removal of feed for a period of up to 14 days. However, this is a practice that is believed to adversely influence the welfare of the hens and there is a need to examine behavoria...

110

In vivo Effects of a Recombinant Molt-Inhibiting Hormone on Molt Interval and Hemolymph Ecdysteroid Level in the Kuruma Prawn, Marsupenaeus japonicus  

Microsoft Academic Search

In order to determine the function of molt-inhibiting hormone (MIH) in vivo , we examined the effects of injecting of a recombinant MIH on the molt interval and hemolymph ecdysteroid level in the kuruma prawn, Marsupenaeus japonicus . The injection of recombinant MIH significantly prolonged the molt interval (9.0 ± 0.4 days in the control group, 9.5 ± 0.5 days

Takuji Okumura; Tsuyoshi Ohira; Hidekazu Katayama; Hiromichi Nagasawa

2005-01-01

111

EFFECT OF DIFLUBENZURON ON AN ESTUARINE CRUSTACEAN  

EPA Science Inventory

Data are reported for tests exposing a small, estuarine crustacean, Mysidopsis bahia, to diflubenzuron (Dimilin, TH-6040, (1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea)) in flowing seawater. Tests were conducted in intermittent flows from a diluter or continuous flowing water i...

112

Ontogenic changes in cardiac function in crustaceans  

Microsoft Academic Search

Ontogenic changes in cardiac function were studied in four different species of crustaceans; the water flea Daphnia magna (“wild-type” and clone), the amphipod Gammarus duebeni, the lobster Nephrops norvegicus and the brine shrimp Artemia franciscana. The pattern of cardiac function, from its first appearance through to sexual maturity, was similar in each of the species examined: the main differences were

John I. Spicer; David Morritt

1996-01-01

113

Molt-inhibiting hormone from the tropical land crab, Gecarcinus lateralis: cloning, tissue expression, and expression of biologically active recombinant peptide in yeast.  

PubMed

Molt-inhibiting hormone (MIH), a member of the crustacean hyperglycemic neuropeptide hormone family, inhibits ecdysteroidogenesis in the molting gland or Y-organ (YO). A cDNA encoding MIH of the land crab (Gel-MIH) was cloned from eyestalk ganglia (EG) by a combination of reverse transcriptase polymerase chain reaction (RT-PCR) and 3'- and 5'-rapid amplification of cDNA ends (RACE). The cDNA (1.4 kb) encoded MIH prohormone containing a 35 amino acid signal peptide and a 78 amino acid mature peptide. The mature peptide had the six cysteines, one glycine, two arginines, one aspartate, one phenylalanine, and one asparagine in identical positions in the highly conserved sequence characteristic of other crustacean MIHs. Gel-MIH was expressed only in the EG, as determined by RT-PCR; it was not detected in Y-organ, heart, integument, gill, testis, ovary, hepatopancreas, thoracic ganglion, or skeletal muscle. A cDNA encoding the mature peptide was used to express recombinant MIH (rMIH) using a yeast (Pichia pastoris) expression system. Two constructs were designed to yield either a mature MIH fusion protein with a c-myc epitope and histidine (His) tag at the carboxyl terminus or an untagged mature protein without the c-myc and His sequences. Immunoreactive peptides were detected in Western blots of the cell culture media with both MIH constructs, indicating secretion of the processed rMIH into the medium. Culture media containing the untagged mature peptide significantly inhibited ecdysteroid secretion by YOs from land crab and green crab (Carcinus maenas) cultured in vitro, indicating that the Gel-rMIH was biologically active. PMID:17094991

Lee, Kara J; Kim, Hyun-Woo; Gomez, Andrea M; Chang, Ernest S; Covi, Joseph A; Mykles, Donald L

2006-11-13

114

Expression and functions of dopa decarboxylase in the silkworm, Bombyx mori was regulated by molting hormone.  

PubMed

Insect molting is an important developmental process of metamorphosis, which is initiated by molting hormone. Molting includes the activation of dermal cells, epidermal cells separation, molting fluid secretion, the formation of new epidermis and old epidermis shed and other series of continuous processes. Polyphenol oxidases, dopa decarboxylase and acetyltransferase are necessary enzymes for this process. Traditionally, the dopa decarboxylase (BmDdc) was considered as an enzyme for epidermal layer's tanning and melanization. This work suggested that dopa decarboxylase is one set of the key enzymes in molting, which closely related with the regulation of ecdysone at the time of biological molting processes. The data showed that the expression peak of dopa decarboxylase in silkworm is higher during molting stage, and decreases after molting. The significant increase in the ecdysone levels of haemolymph was also observed in the artificially fed silkworm larvae with ecdysone hormone. Consistently, the dopa decarboxylase expression was significantly elevated compared to the control. BmDdc RNAi induced dopa decarboxylase expression obviously declined in the silkworm larvae, and caused the pupae appeared no pupation or incomplete pupation. BmDdc was mainly expressed and stored in the peripheral plasma area near the nucleus in BmN cells. In larval, BmDdc was mainly located in the brain and epidermis, which is consisted with its function in sclerotization and melanization. Overall, the results described that the dopa decarboxylase expression is regulated by the molting hormone, and is a necessary enzyme for the silkworm molting. PMID:23640098

Wang, Mei-xian; Cai, Zi-zheng; Lu, Yan; Xin, Hu-Hu; Chen, Rui-ting; Liang, Shuang; Singh, Chabungbam Orville; Kim, Jong-Nam; Niu, Yan-shan; Miao, Yun-gen

2013-05-03

115

The timing of wing molt in tundra swans: energetic and non-energetic constraints  

USGS Publications Warehouse

Date of wing molt initiation, based on the regression of tenth primary length on capture date, was calculated for breeding and nonbreeding Tundra Swans (Cygnus columbianus columbianus) on the Colville River Delta, Alaska. Breeding females initiated wing molt significantly later than breeding males and nonbreeding males and females; the molt of breeding females was correlated with the date on which their eggs hatched. Breeding males did not differ significantly from nonbreeding males and females in the date of molt initiation. Timing of molt in breeding males and females was consistent with the views that females delay molt while replenishing energy spent on reproduction, but was also consistent with the breeding pair's need for primaries to defend territories and to defend and brood young. Other results, including an increase in an index of female body condition throughout most of the molt period, and a positive correlation between clutch size and female hatch-to-molt interval, were not predicted by the hypothesis that past energy expenditures constrain the timing of molt. Patterns of wing molt within and among other Northern Hemisphere geese and swans are also difficult to explain on the basis of energetics alone. For example, breeding females initiate molt before breeding males in many species. Also, there is extreme asynchrony between mates in two swan species; one of those species also exhibits variation in which sex initiates wing molt first. Both patterns suggest that asynchrony, per se, is important, probably to facilitate brood protection or territory defense. In Tundra Swans and other northern breeding geese and swans, the non-energetic demands of territory defense, brood defense, and brooding are probably important constraints on the timing of wing molt.

Earnst, S. L.

1992-01-01

116

Temporal and spatial shifts in habitat use by Black Brant immediately following flightless molt  

USGS Publications Warehouse

Each year thousands of Pacific Black Brant (Branta bernicla nigricans) undergo flightless wing molt in the Teshekpuk Lake Special Area (TLSA), Alaska, in two distinct habitats: inland, freshwater lakes and coastal, brackish wetlands. Brant lose body mass during wing molt and likely must add reserves upon regaining flight to help fuel their 2,500 km migration to autumn staging areas. We characterized movements and habitat use by Brant during post-molt (the period immediately following the recovery of flight) by (1) marking individual Brant with GPS (global positioning system) transmitters, and (2) conducting a series of replicate aerial surveys. Individuals molting in inland habitats promptly abandoned their molt wetland during the post-molt and moved into coastal habitats. Consequently, inland habitats were nearly deserted by early August when Brant had regained flight, a decrease of >5,000 individuals from the flightless period of early July. Conversely, coastal molting Brant largely remained in coastal habitats during the post-molt and many coastal wetlands were occupied by large flocks (>1,000 birds). Our results indicate that inland, freshwater wetlands were less suitable post-molt habitats for Brant, while coastal wetlands were preferred as they transitioned from flightless molt. The immediacy with which Brant vacated inland habitats upon regaining flight suggests that food may be limiting during molt and they are not selecting inland molt sites strictly for food resources, but rather a balance of factors including predator avoidance and acquisition of protein for feather growth. Our data clearly demonstrate that patterns of habitat use by Brant in the TLSA change over the course of the molt season, an important consideration for management of future resource development activities in this area. ?? 2010 by the Wilson Ornithological Society.

Lewis, T. L.; Flint, P. L.; Schmutz, J. A.; Derksen, D. V.

2010-01-01

117

Lake acidification: Effects on crustacean zooplankton populations  

SciTech Connect

The ranked acid sensitivities of six common crustacean zooplankton taxa were determined from a multilake field survey in Ontario and from laboratory bioassays. The two approaches gave the same ranking (from most to least sensitive): Daphnia galeata mendotae, Daphnia retrocurva, and Skistodiaptomus oregonensis > Diaphanosoma birgei > Mesocyclops edax > Bosmina longirostris. This finding suggests that acidification has caused the widespread damage which has been documented for the zooplankton of Ontario and northeastern US lakes. 24 refs., 3 figs., 2 tabs.

Havens, K.E. (Kent State Univ., OH (United States)); Yan, N.D. (Ontario Ministry of the Environment, Dorset (Canada)); Keller, W. (Ontario Ministry of the Environment, Sudbury (Canada))

1993-08-01

118

Survival and movements of molting male black ducks in Labrador  

USGS Publications Warehouse

We marked 26 flightless male American black ducks with transmitters during the post-nuptial molt in northern Labrabor to determine survival and movements. Twelve ducks remained in the watershed where marked and 11 ducks moved to different watersheds. The period survival rate (PSR) for these flightless males was 0.89 using the Kaplan-Meier estimator. Only 2 ducks were killed by predators. Death of these 2 ducks might have been influenced by our disturbance, thus we considered the PSR minimal.

Bowman, T.D.; Longcore, J.R.

1989-01-01

119

Demographic characteristics of molting black brant near Teshekpuk Lake, Alaska  

USGS Publications Warehouse

Molting Brant in the Teshekpuk Lake Special Area (TLSA) on the Arctic Coastal Plain of Alaska were studied from 1987 to 1992 using capture-mark-recapture techniques to determine origin, age and sex composition, return rates and site fidelity. Brant originated from 10 nesting colonies in Canada and Alaska. The captured birds were 76% adults and 57% males. Ninety-one percent of known-age recaptures were

Bollinger, K. S.; Derksen, D. V.

1996-01-01

120

Chronobiology of deep-water decapod crustaceans on continental margins.  

PubMed

Species have evolved biological rhythms in behaviour and physiology with a 24-h periodicity in order to increase their fitness, anticipating the onset of unfavourable habitat conditions. In marine organisms inhabiting deep-water continental margins (i.e. the submerged outer edges of continents), day-night activity rhythms are often referred to in three ways: vertical water column migrations (i.e. pelagic), horizontal displacements within benthic boundary layer of the continental margin, along bathymetric gradients (i.e. nektobenthic), and endobenthic movements (i.e. rhythmic emergence from the substrate). Many studies have been conducted on crustacean decapods that migrate vertically in the water column, but much less information is available for other endobenthic and nektobenthic species. Also, the types of displacement and major life habits of most marine species are still largely unknown, especially in deep-water continental margins, where steep clines in habitat factors (i.e. light intensity and its spectral quality, sediment characteristics, and hydrography) take place. This is the result of technical difficulties in performing temporally scheduled sampling and laboratory testing on living specimens. According to this scenario, there are several major issues that still need extensive research in deep-water crustacean decapods. First, the regulation of their behaviour and physiology by a biological clock is almost unknown compared to data for coastal species that are easily accessible to direct observation and sampling. Second, biological rhythms may change at different life stages (i.e. size-related variations) or at different moments of the reproductive cycle (e.g. at egg-bearing) based on different intra- and interspecific interactions. Third, there is still a major lack of knowledge on the links that exist among the observed bathymetric distributions of species and selected autoecological traits that are controlled by their biological clock, such as the diel rhythm of behaviour. Species evolved in a photically variable environment where intra- and inter-specific interactions change along with the community structure over 24 h. Accordingly, the regulation of their biology through a biological clock may be the major evolutionary constraint that is responsible for their reported bathymetric distributions. In this review, our aim is to propose a series of innovative guidelines for a discussion of the modulation of behavioural rhythms of adult decapod crustaceans, focusing on the deep waters of the continental margin areas of the Mediterranean as a paradigm for other marine zones of the world. PMID:20959158

Aguzzi, Jacopo; Company, Joan B

2010-01-01

121

Progress of primary feather molt of adult mourning doves in Missouri  

USGS Publications Warehouse

The examination of 7,892 adult doves in Missouri between 1953 and 1965 showed that less than 2.5% of adult doves completed their molt before October 1. Adult doves of both sexes began molting their primary feathers during early June in Missouri and lost the last (tenth) primary during the latter half of October. Approximately 140-150 days were required to complete the molt. Thus, early-hatched immatures, which begin their primary molt 25-30 days after hatching, contributed the bulk of the wings with completed molts in September. By correctly classifying September samples of dove wings with a completed molt as young-of-the-year a more accurate young:adult ratio is obtained.

Sadler, K.C.; Tomlinson, R.E.; Wight, H.M.

1970-01-01

122

Variation in plumage, molt, and morphology of the Whiskered Auklet (Aethia pygmaea) in Alaska  

USGS Publications Warehouse

We studied molt and size variation in Whiskered Auklets collected at sea in August from the Aleutian Islands in 1992 and 1993. We evaluated size differences from external and skeletal measurements. Adults were molting extensively in August, indicating that molt began in July. Primaries 1-5 had been completely replaced, while primaries 6-8 were in various stages of replacement, and primaries 9 and 10 were old in most birds. We also found that juveniles were not molting. This pattern is similar to other species of small auklets where breeding and molt in adults overlap, but juveniles do not molt until the following summer. This suggests that Whiskered Auklets are subjected to similar ecological constraints as other auklets. We provide the first skeletal measurements of Whiskered Auklets and some new external measurements. Results of statistical analyses indicate that there is no sexual dimorphism in adults. A small sample of juveniles suggests that they are similar in size to adults.

Pitocchelli, J.; Piatt, J. F.; Carter, H. R.

2003-01-01

123

50 CFR 665.440 - Mariana crustacean fisheries. [Reserved  

Code of Federal Regulations, 2011 CFR

...MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC Mariana Archipelago Fisheries § 665.440 Mariana crustacean fisheries....

2011-10-01

124

Hormonal correlates and thermoregulatory consequences of molting on metabolic rate in a northerly wintering shorebird.  

PubMed

Even though molt involves both endocrine and energetic changes in bird bodies, this study is among the first to combine assessments of energy costs together with thyroid hormone variations in molting birds. Individual shorebirds (red knots Calidris canutus islandica) were measured while in full summer and winter plumage as well as during peak of molt. Molt was associated with a 9.8% increase in average mass-independent basal metabolic rate (BMR) above nonmolting levels. Individual plasma levels of thyroxine (T(4)) were correlated with individual rate of body feather renewal, confirming that T(4) is related to body molt but also showing that it is potentially regulating its rate. Across seasons, mass-independent average heat loss measured as conductance gradually declined with conductance during molt falling between measured values for summer and winter. During the molting period, however, body molting rate was positively correlated with thermal conductance, indicating that for a given ambient temperature below thermoneutrality, the fastest molting birds were losing more body heat. Across seasons, triiodothyronine (T(3)), a hormone typically upregulated in response to a cold stimulus, was correlated with individual thermal conductance and BMR. We suggest that the increased heat loss of fast-molting birds leads to a cold-acclimatization response that may be partly responsible for the elevated BMR measured during molt. This could be mediated through a stimulatory effect of T(3) on BMR in response to increased heat loss. Our interpretation is supported by a positive relationship between the individual changes in conductance and the change in BMR from summer to the molting period. PMID:19199554

Vézina, François; Gustowska, Anna; Jalvingh, Kirsten M; Chastel, Olivier; Piersma, Theunis

125

Intestinal and eggshell calbindin, and bone ash of laying hens as influenced by age and molting.  

PubMed

A series of trials was conducted in order to study the effects of age and molt on intestinal and eggshell gland (ESG) calbindin, and on bone ash. For this purpose an ELISA for chicken calbindin was developed. Age did not significantly affect duodenal or ESG calbindin. Bone ash increased (but not significantly in this study) from 8 to 16 months of age. During molt induction, egg laying was arrested, duodenal and ESG calbindin almost completely disappeared and ovary mass, plasma estradiol and total calcium (Ca) decreased markedly, whereas bone ash and body mass (BW) decreased moderately. During the non-laying period that followed the feed withdrawal period, duodenal and ESG calbindin remained low, whereas plasma estradiol and other estrogen-dependent variables, such as plasma total Ca and bone ash, increased slightly. At the onset of egg production following molting, duodenal and ESG calbindin levels were similar to pre molt level. Bone ash was higher than at the pre molt period. Body mass, small yellow follicles, ovary and oviduct mass and plasma estradiol were lower than their values prior to molt induction. Bone ash contents in the molted hens at the ages of 583 and 820 days were similar to or even slightly higher than those in the non-molted hens, whereas duodenal and ESG calbindin were not significantly different. These results suggest that the improvement of shell quality in the molted birds does not involve mechanisms associated with calbindin synthesis. PMID:14613795

Yosefi, Sara; Braw-Tal, Ruth; Bar, Arie

2003-11-01

126

Population dynamics and parasitation of planktonic and epibenthic crustaceans in the Baltic Schlei fjord  

NASA Astrophysics Data System (ADS)

The planktonic and epibenthic crustacean fauna from two sites of the brackish Schlei fjord, Northern Germany, was investigated over a six-month period. Calanoid and cyclopoid copepods were more abundant in lower salinities, whereas, benthic decapods, isopods and amphipods prevailed in the site of higher salinity. Cestodan larvae were found only in spring which may be due to the timing of the respective life-cycles. Parasites of benthic crustaceans, mostly digenean metacercariae but also cestodans, acanthocephalans and nematodes, appeared from spring to late summer. Decreasing salinities caused lower intensities of the most abundant parasite, Maritrema subdolum; only the true brackish-water species among the hosts were more heavily infested than those found in higher salinities. The correlation of parasite size and host size at infestation became apparent. Therefore, Crangon crangon is an optimal host for the large Podocotyle atomon metacercariae. Coevolutive trends between some hosts and parasites are made evident.

Gollasch, S.; Zander, C. D.

1995-03-01

127

Arsenic trioxide induces apoptosis equally in T lymphoblastoid leukemia MOLT4 cells and P-gp-expressing daunorubicin-resistant MOLT4 cells  

Microsoft Academic Search

Purpose. To investigate the effects of arsenic trioxide (As2O3) on human T-lymphoblastoid leukemia MOLT-4 cells and P-gp-expressing daunorubicin-resistant MOLT-4 (MOLT-4\\/DNR) cells. Methods. Cell growth was measured by an MTT assay. Cell viability was determined by a dye exclusion test. The level of P-gp expression was estimated using phycoerythrin-conjugated anti-P-gp monoclonal antibody 17F9. The function of P-gp was evaluated in terms

Xiao-Mei Hu; Toshihiko Hirano; Kitaro Oka

2003-01-01

128

Biogenic Amines and Aggression: Experimental Approaches in Crustaceans  

Microsoft Academic Search

This review summarizes our experimental approaches attempting to link amines and their metabolites to aggression in crustaceans. The results demonstrate (i) that agonistic behavior in crustaceans can be quantified, (ii) that the amines themselves have telling and subtle effects on the fighting behavior of animals, (iii) that pharmacological interventions are possible that might allow a biochemical dissection of the underlying

R. Huber; M. Orzeszyna; N. Pokorny; E. A. Kravitz

1997-01-01

129

Limnetic crustacean zooplankton of Lake Oahe, May-October 1969  

USGS Publications Warehouse

The limnetic crustacean zooplankton of Lake Oahe was dominated by copepods. Cyclops bicuspidatus thomasi was the dominant crustacean throughout the lake. Mesocyclops edax, Diaptomus ashlandi and Daphnia pulex were major components of the zooplankton in the deep, downstream portion of the lake while Bosmina longirostris and Daphnia retrocurva were important constituents in the river-like, upstream section of the lake.

Selgeby, James H.

1974-01-01

130

Bergmann's Principle and Deep-Water Gigantism in Marine Crustaceans  

Microsoft Academic Search

We present a review of the Bergmann's principle and deep-water gigantism in marine crustaceans. An increase in the geographic latitude and depth of crustaceans habitat (correlating mainly with lower temperatures) leads to an increased cell size, life span of the animal, and, as a result, an increase in the body size. Since Bergmann's principle and deep-water gigantism appear to be

S. F. Timofeev

2001-01-01

131

In vivo effects of a recombinant molt-inhibiting hormone on molt interval and hemolymph ecdysteroid level in the kuruma prawn, Marsupenaeus japonicus.  

PubMed

In order to determine the function of molt-inhibiting hormone (MIH) in vivo, we examined the effects of injecting of a recombinant MIH on the molt interval and hemolymph ecdysteroid level in the kuruma prawn, Marsupenaeus japonicus. The injection of recombinant MIH significantly prolonged the molt interval (9.0 +/-0.4 days in the control group, 9.5+/-0.5 days in the 2500 ng/g-body weight/injection-group, mean+/-SD), and significantly decreased the hemolymph ecdysteroid level (ratio of levels between after and before injection: 1.94+/-1.09 in the control and 1.28+/-0.39 in the 3000 ng/g-body weight/injection-group, mean+/-SD). These results conclusively show the inhibitory effects of MIH on molting in vivo. PMID:15795494

Okumura, Takuji; Ohira, Tsuyoshi; Katayama, Hidekazu; Nagasawa, Hiromichi

2005-03-01

132

Social Facilitation of Synchronized Molting Behavior in the Spider Amaurobius ferox (Araneae, Amaurobiidae)  

Microsoft Academic Search

During the social period, molting behavior of the young spider, Amaurobius ferox, is highly synchronized within the clutch. Result of the experimental study suggests that social facilitation among group members increased the synchronization. The duration of the molting period of grouped spiderlings was significantly shorter than that of individually isolated spiderlings. Involving the particular maternal strategy in food supply, this

Kil Won Kim

2001-01-01

133

Molting and cuticle deposition in the subterranean trichoniscid Titanethes albus (Crustacea, Isopoda)  

PubMed Central

Abstract Terrestrial isopods are a suitable group for the study of cuticle synthesis and calcium dynamics because they molt frequently and have evolved means to store calcium during molt. Little data is currently available on molting in Synocheta and subterranean isopods. We studied the molting dynamics in the subterranean trichoniscid Titanethes albus under laboratory conditions and performed a microscopic investigation of sternal CaCO3 deposits and the tergal epithelium during molt in this species. In accordance with its lower metabolic rate, molting in the laboratory is roughly 2–3 times less frequent in Titanethes albus than would be expected for an epigean isopod under similar conditions. Animals assumed characteristic postures following the molt of each body half and did not consume the posterior exuviae after posterior molt. The structure of sternal calcium deposits and the ultrastructural characteristics of the epidermis during cuticle formation in Titanethes albus are similar to those described in representatives of Ligiidae. During the deposition of the exocuticle, the apical plasma membrane of epidermal cells forms finger-like extensions and numerous invaginations. In the ecdysial space of individuals in late premolt we observed cellular extensions surrounded by bundles of tubules.

Vittori, Milos; Kostanjsek, Rok; Znidarsic, Nada; Strus, Jasna

2012-01-01

134

Isolation and Purification of the Molting Hormones from the American Lobster (Homarus americanus).  

National Technical Information Service (NTIS)

A detailed procedure for the isolation of molting hormones from a lobster is described. Ecdysterone has been isolated from postmolt adult female lobsters. This molting hormone by itself, or in combination with other ecdysones, plays a major role in the mo...

R. B. Gagosian R. A. Bourbonniere

1974-01-01

135

Survival and other observations of adult female northern pintails molting in California  

USGS Publications Warehouse

Survival rates of nine adult female Northern Pintails (Anas acuta) that became flightless after being radio-marked in the Sacramento Valley, California in August 1987-1989 were estimated. Seven of the radio-marked pintails molted in the Sacramento Valley, a nontraditional molting region, and two flew 280 km north to the Klamath Basin to molt. Molting marshes were dominated by emergent vegetation in both locations. Two ducks, while flightless in the Sacramento Valley, were killed by predators. Molting pintails remained sedentary (did not fly) for an average of 36 d, and the daily survival rate during this period was 0.9934. The resulting sedentary-period survival rate was 0.79. Primary feather 9 on two captive ducks grew an average of 4.2 mm per day. Mean body mass of molting ducks that died was lower than that for molting ducks that survived (P < 0.10). The number of pintails molting on Sacramento Valley refuges is probably <200.

Miller, M. R.; Fleskes, J. P.; Orthmeyer, D. L.; Gilmer, D. S.

1992-01-01

136

Molt performance and bone density of cortical, medullary, and cancellous bone in laying hens during feed restriction or alfalfa-based feed molt.  

PubMed

A study was conducted to evaluate the effects of alfalfa-based molt diets on molting performance and bone qualities. A total of 36 Single Comb White Leghorn hens were used for the study. There were 6 treatments: pretrial control (PC), fully fed (FF), feed withdrawal (FW), 90% alfalfa:10% layer ration (A90), 80% alfalfa:20% layer ration (A80), and 70% alfalfa:30% layer ration (A70). For the PC treatment, hens were euthanized by CO(2) gas, and bones were collected before molt was initiated. At the end of the 9-d molt period, hens were euthanized, and femurs and tibias were collected to evaluate bone qualities by peripheral quantitative computed tomography, mechanical testing, and conventional ash weights. The hens fed alfalfa-based molt diets and FW stopped laying eggs within 5 d after molt started, and all hens in these groups had reduced ovary weights compared with those of the FF hens. In the FW and A90 groups, total femur volumetric bone mineral densities (vBMD) at the midshaft were significantly lower, but those of the A80 and A70 groups were not significantly different from the values for the PC and FF hens. In cortical bone density, the midshaft tibial vBMD were significantly higher for FF and A70 hens than for PC hens. The medullary bone densities at the midshaft femur or tibia of the FW, A90, A80, and A70 hens were reduced compared with those of the PC hens. Femur cancellous densities at the distal femur for the FW and A90 hens were significantly reduced compared with those of the PC and FF hens. The FW, A80, and A70 hens yielded significantly higher elastic moduli, and the A80 hens had higher ultimate stress compared with the PC hens, suggesting that the mechanical integrity of the midshaft bone was maintained even though the medullary vBMD was reduced. These results suggest that alfalfa-based molt diets exhibit molt performance similar to FW, that medullary and cancellous bones are labile bone compartments during molting, and that alfalfa-based molt diets may be beneficial to maintain the mechanical properties of bones during molt. PMID:17704367

Kim, W K; Donalson, L M; Bloomfield, S A; Hogan, H A; Kubena, L F; Nisbet, D J; Ricke, S C

2007-09-01

137

Calcium transport mechanism in molting crayfish revealed by microanalysis  

SciTech Connect

Crayfish provide a good model in which to study the transport mechanism of Ca ions. During the molting stage, decalcified Ca ions are transferred into the blood and accumulate in the gastrolith epithelium, after which a gastrolith is formed on the surface of the epithelium. The gastrolith is dissolved in the stomach after molting, and the Ca is reabsorbed and redistributed throughout the newly formed exoskeleton. We studied the mechanism of Ca transport by cytochemical precipitation of Ca ions and by electron microanalysis, including X-ray microanalysis (EDX) and electron energy-loss spectroscopy (EELS), with a computer. In EDX analysis, the fine precipitates of K-antimonate in the gastrolith mitochondria clearly defined Ca with antimony; we also observed a large amount of Ca-oxalate in the mitochondria, and Ca-K X-ray pulses were clearly defined. Ca-K X-rays were also detected from fresh freeze-substituted mitochondria. Finally, we succeeded in taking a Ca-L EELS image from the mitochondria of fresh freeze-substituted thin sections. Only a very small amount of Ca was detected from the cell membrane and other organelles. Ca-adenosine triphosphatase (ATPase) and Mg-ATPase activity was also very clearly demonstrated in the mitochondria. These enzymes may play an important role in Ca metabolism.

Mizuhira, V.; Ueno, M.

1983-01-01

138

Requirements for molting of the crochet epidermis of the tobacco hornworm larva in vivo and in vitro  

Microsoft Academic Search

In the tobacco hornworm,Manduca sexta, the epidermis which underlies the larval crochets is the first tissue to become independent of the prothoracic glands (PG) in a larval molt. In each successive larval molt, crochet forming cells increase in size, form hooks at their distal ends and, finally, secrete cuticle. This paper examines the endocrine requirements for competence to molt and

Margery J. Fain; Lynn M. Riddiford

1977-01-01

139

[Bergmann's principle and deep-water gigantism in marine crustaceans].  

PubMed

We present a review of the Bergmann's principle and deep-water gigantism in marine crustaceans. An increase in the geographic latitude and depth of crustaceans habitat (correlating mainly with lower temperatures) leads to an increased cell size, life span of the animal, and, as a result, an increase in the body size. Since Bergmann's principle and deep-water gigantism appear to be based on the same biological mechanisms, we propose a unified principle, according to which the size of the crustacean's body increases along the temperature gradient. PMID:15926344

Timofeev, S F

140

Radio-sensitization of human leukaemic molt-4 cells by DNA-dependent protein kinase inhibitor, NU7026.  

PubMed

In this paper we describe the influence of NU7026, a specific inhibitor of DNA-dependent protein kinase, phosphoinositide 3-kinase, and ATM-kinase on molecular and cellular mechanisms triggered by ionising irradiation in human T-lymphocyte leukaemic MOLT-4 cells. We studied the effect of this inhibitor (10 1microM) combined with gamma-radiation (1 Gy) leading to DNA damage response and induction of apoptosis. We used methods for apoptosis assessment (cell viability count and flow-cytometric analysis) and cell cycle analysis (DNA content measurement) and we detected expression and post-translational modifications (Western blotting) of proteins involved in DNA repair signalling pathways. Pre-treatment with NU7026 resulted into decreased activation of checkpoint kinase-2 (Thr68), p53 (Ser15 and Ser392), and histone H2A.X (Ser139) 2 hours after irradiation. Subsequently, combination of radiation and inhibitor led to decreased amount of cells in G2-phase arrest and into increased apoptosis after 72 hours. Our results indicate that in leukaemic cells the pre-incubation with inhibitor NU7026 followed by low doses of ionising radiation results in radio-sensitising of MOLT-4 cells via diminished DNA repair and delayed but pronounced apoptosis. This novel approach might offer new strategies in combined treatment of leukaemia diseases. PMID:23101268

Tichý, Ales; Novotná, Eva; Durisová, Kamila; Salovská, Barbora; Sedlaríková, Radka; Pejchal, Jaroslav; Zárybnická, Lenka; Vávrová, Jirina; Sinkorová, Zuzana; Rezácová, Martina

2012-01-01

141

Breeding chronology, molt, and measurements of accipiter hawks in northeastern Oregon  

USGS Publications Warehouse

Most northern goshawks completed laying eggs in April, while most Cooper's hawks completed their clutches in May with essentially no overlap. The sharp-shinned hawks laid in late May and June. Juvenile females represented 4% of the northern goshawk breeding population; 22% of the Cooper's hawk breeding population (highest reported for the species) and 60% of the sharp-shinned hawk breeding population, northern goshawks and Cooper's hawks in juvenal plumage generally nested later in the season, but not sharp-shinned hawks. Females of each species began molting first. Primaries were molted from the innermost outward in all species, but rectrix molt sequence was variable. Usually R1 was molted first. Primary molt of the 2 wings was usually synchronous; however, the rectrix molt was not as orderly. Arrested molt was observed in some individuals of all species; it probably has an energy-saving function. Wing chords of adult northern goshawks from Oregon were not different from Wisconsin fall migrants or birds from Alaska; however, rectrices were significantly shorter in Oregon than Wisconsin. Cooper's hawks nesting in Oregon were much smaller than those trapped in Wisconsin. Wing chords and rectrices were significantly shorter for both sexes, and, although weights were not directly comparable, Oregon Cooper's hawks also weighed much less. The limited number of sharp-shinned hawks measured precluded statistical analyses.

Henny, C.J.; Olson, R.A.; Fleming, T.L.

1985-01-01

142

Physiological trade-offs in self-maintenance: plumage molt and stress physiology in birds.  

PubMed

Trade-offs between self-maintenance processes can affect life-history evolution. Integument replacement and the stress response both promote self-maintenance and affect survival in vertebrates. Relationships between the two processes have been studied most extensively in birds, where hormonal stress suppression is down regulated during molt in seasonal species, suggesting a resource-based trade-off between the two processes. The only species found to differ are the rock dove and Eurasian tree sparrow, at least one of which performs a very slow molt that may reduce resource demands during feather growth, permitting investment in the stress response. To test for the presence of a molt-stress response trade-off, we measured hormonal stress responsiveness during and outside molt in two additional species with extended molts, red crossbills (Loxia curvirostra) and zebra finches (Taeniopygia guttata). We found that both species maintain hormonal stress responsiveness during molt. Further, a comparative analysis of all available species revealed a strong relationship between molt duration and degree of hormonal suppression. Though our results support trade-off hypotheses, these data can also be explained by alternative hypotheses that have not been formally addressed in the literature. We found a strong relationship between stress suppression and seasonality of breeding and evidence suggesting that the degree of suppression may be either locally adaptable or plastic and responsive to local environmental conditions. We hypothesize that environmental unpredictability favors extended molt duration, which in turn allows for maintenance of the hormonal stress response, and discuss implications of a possible trade-off for the evolution of molt schedules. PMID:21795575

Cornelius, Jamie M; Perfito, Nicole; Zann, Richard; Breuner, Creagh W; Hahn, Thomas P

2011-08-15

143

Blood chemistry of wild Brazilian Coscoroba Swans during molt.  

PubMed

The Coscoroba Swan (Coscoroba coscoroba) is an unusual member of the Anatidae found in South America, from the Falkland Islands and Tierra del Fuego through Chile and Argentina, Uruguay, and Paraguay as far north as Mato Grosso do Sul in Brazil. The species is not threatened globally, but some local populations have declined and the status of others is unknown. The objective of this study was to quantify the plasma chemistry of a wild population of Coscoroba Swans in southern Brazil during their molting period. We captured 12 chicks, 14 juveniles, and 31 mature birds. The following blood parameters were measured: glucose, cholesterol, triglycerides, HDL cholesterol, uric acid, creatine-kinase, aspartate amino transferase, alanine-aminotransferase, alkaline phosphatase, amylase, and pancreatic amylase. Significant differences between males and females were not observed for any of the parameters, and only the levels of alkaline phosphatase differed significantly among age groups. PMID:20688656

Calabuig, Cecilia Pérez; Ferrer, Miguel; Muriel, Roberto

2010-04-01

144

Hox genes and study of Hox genes in crustacean  

NASA Astrophysics Data System (ADS)

Homeobox genes have been discovered in many species. These genes are known to play a major role in specifying regional identity along the anterior-posterior axis of animals from a wide range of phyla. The products of the homeotic genes are a set of evolutionarily conserved transcription factors that control elaborate developmental processes and specify cell fates in metazoans. Crustacean, presenting a variety of body plans not encountered in any other class or phylum of the Metazoa, has been shown to possess a single set of homologous Hox genes like insect. The ancestral crustacean Hox gene complex comprised ten genes: eight homologous to the hometic Hox genes and two related to nonhomeotic genes presented within the insect Hox complexes. The crustacean in particular exhibits an abundant diversity segment specialization and tagmosis. This morphological diversity relates to the Hox genes. In crustacean body plan, different Hox genes control different segments and tagmosis.

Hou, Lin; Chen, Zhijuan; Xu, Mingyu; Lin, Shengguo; Wang, Lu

2004-12-01

145

50 CFR 665.240 - Hawaii crustacean fisheries. [Reserved  

Code of Federal Regulations, 2011 CFR

50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Hawaii crustacean fisheries. [Reserved] 665.240 Section 665.240 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...

2011-10-01

146

50 CFR 665.640 - PRIA crustacean fisheries. [Reserved  

Code of Federal Regulations, 2012 CFR

50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false PRIA crustacean fisheries. [Reserved] 665.640 Section 665.640 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...

2012-10-01

147

50 CFR 665.240 - Hawaii crustacean fisheries. [Reserved  

Code of Federal Regulations, 2012 CFR

50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Hawaii crustacean fisheries. [Reserved] 665.240 Section 665.240 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...

2012-10-01

148

50 CFR 665.440 - Mariana crustacean fisheries. [Reserved  

Code of Federal Regulations, 2012 CFR

50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Mariana crustacean fisheries. [Reserved] 665.440 Section 665.440 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...

2012-10-01

149

Deception in Visual and Chemical Communication in Crustaceans  

Microsoft Academic Search

\\u000a Deception in animal communication occurs when one animal causes another to respond to a condition that does not exist or to\\u000a fail to respond to one that does. Signals that bluff produce the first kind of error, behavior that hides causes the second,\\u000a and both are common in visual communication by crustaceans. In contrast, crustacean chemical communication may usually be

John H. Christy; Dan Rittschof

150

Crustacean hyperglycemic hormone from the tropical land crab, Gecarcinus lateralis: cloning, isoforms, and tissue expression.  

PubMed

Crustacean hyperglycemic hormone (CHH) regulates carbohydrate metabolism, molting, and ion and water transport. cDNAs encoding four CHH isoforms (designated EG-CHH-A, -B, -C, and -D) were cloned from eyestalk ganglia (EG) from land crab, Gecarcinus lateralis. The isoforms differed in the 3' region of the open reading frame and/or the length of the 3' untranslated region. All encoded essentially identical preprohormones containing a 28-amino acid (aa) signal peptide, a 42-aa precursor related peptide and a 72-aa mature CHH. All deduced aa sequences had the six cysteines, two arginines, one aspartate, one phenylalanine, and one arginine originally identified as characteristic of this neuropeptide family. There was a single aa difference between the EG-CHH-D mature hormone and the other three isoforms. The EG-CHH isoforms were expressed in EG, hindgut, and thoracic ganglion. A fifth CHH isoform, designated pericardial organ (PO)-CHH, was similar to the PO-CHH isoform described in green crab, Carcinus maenas. It was expressed in hindgut and testis, but not in eyestalk ganglia; its expression in PO was not determined. The deduced aa sequence of the PO-CHH was identical to that of the EG-CHH isoforms through aa #40 of the mature peptide. The divergent aa sequence between positions #41 and #73 was encoded by an insertion of a 111-bp sequence absent in EG-CHH cDNAs. The data suggest that EG-CHH and PO-CHH isoforms are generated by alternative splicing of at least two CHH genes. PMID:17586505

Lee, Kara J; Doran, Rachelle M; Mykles, Donald L

2007-05-24

151

Evidence for a Molt Inhibiting Hormone in the Barnacle 'Balanus improvisus' (Crustacea, Cirripedia).  

National Technical Information Service (NTIS)

The type of neuroendocrine system regulating molting hormone production in the Cirripedia was investigated. Eyestalk extracts of Uca pugilator, when injected into Stage C Balanus improvisus, had no effect on the time to ecdysis, but significantly increase...

C. W. Davis J. D. Costlow

1974-01-01

152

Trade-offs between molt and immune activity in two populations of house sparrows ( Passer domesticus )  

Microsoft Academic Search

Molt and immune defense are critical activities in which all birds must invest. Because each is costly, wild passerines may have to decrease their investment in one activity if they are to increase investments to others. Here, I studied such molt-immune trade-offs in one neotropical and one north-temperate population of house sparrows (Passer domesticus (L., 1758)). I included two populations

Lynn B. Martin II

2005-01-01

153

Effects of Estrogenic Xenobiotics on Molting of the Water Flea, Daphnia magna  

Microsoft Academic Search

The effects of five xenobiotics, 2,4,5-trichloribiphenyl (PCB29), the polychlorinated biphenyl (PCB) Aroclor 1242, diethyl phthalate, lindane, and 4-octylphenol, on molting ofDaphnia magnawere investigated. All except PCB29 are known to have unexpected estrogenicity in vertebrates. Daphnids exposed to PCB29, Aroclor 1242, and diethyl phthalate took significantly more time to complete four molts than did the controls. The inhibitory effects of theseortho-chlorinated

Enmin Zou; Milton Fingerman

1997-01-01

154

Timing of breeding and molting in six species of Hawaiian honeycreepers  

USGS Publications Warehouse

The timing of breeding and molting was studied in six species of Hawaiian honeycreepers with differing food habits on the Island of Hawaii. The availability of nectar was highly seasonal, whereas insect abundance was relatively constant throughout the year. All six species of honeycreeper had extended breeding and molting periods with peak breeding between April and July and peak molting in August. Breeding and molting periods for Apapane (Himatione sanguinea) and Iiwi (Vestiaria coccinea), two nectarivorous species, were shorter than those for the more insectivorous Common Amakihi (Hemignathus virens), Hawaii Creeper (Oreomystis mana), Akepa (Loxops coccineus), and Akiapolaau (Hemignathus munroi). Missing or growing flight feathers and either a brood patch or enlarged cloacal protuberance occurred simultaneously in only 3.2% of 2.786 adult birds examined. Although overlap of breeding and molting was rare, some individuals may have been able to allocate energy resources to both activities because of low clutch size, extended brooding of young, and a low rate of molting.

Ralph, C.J.; Fancy, S.G.

1994-01-01

155

Host partitioning by parasites in an intertidal crustacean community.  

PubMed

Patterns of host use by parasites throughout a guild community of intermediate hosts can depend on several biological and ecological factors, including physiology, morphology, immunology, and behavior. We looked at parasite transmission in the intertidal crustacean community of Lower Portobello Bay, Dunedin, New Zealand, with the intent of: (1) mapping the flow of parasites throughout the major crustacean species, (2) identifying hosts that play the most important transmission role for each parasite, and (3) assessing the impact of parasitism on host populations. The most prevalent parasites found in 14 species of crustaceans (635 specimens) examined were the trematodes Maritrema novaezealandensis and Microphallus sp., the acanthocephalans Profilicollis spp., the nematode Ascarophis sp., and an acuariid nematode. Decapods were compatible hosts for M. novaezealandensis, while other crustaceans demonstrated lower host suitability as shown by high levels of melanized and immature parasite stages. Carapace thickness, gill morphology, and breathing style may contribute to the differential infection success of M. novaezealandensis and Microphallus sp. in the decapod species. Parasite-induced host mortality appears likely with M. novaezealandensis in the crabs Austrohelice crassa, Halicarcinus varius, Hemigrapsus sexdentatus, and Macrophthalmus hirtipes, and also with Microphallus sp. in A. crassa. Overall, the different parasite species make different use of available crustacean intermediate hosts and possibly contribute to intertidal community structure. PMID:20950092

Koehler, Anson V; Poulin, Robert

2010-04-30

156

Insect molting hormone and sterol biosynthesis in spinach  

SciTech Connect

Insect molting hormones, which are produced by plants and are effective molecules in the control of insect crop pests, are biosynthesized in developing spinach leaves (Spinacia oleracea L.). The major sterols biosynthesized by spinach are avenasterol (24{alpha}-ethyl-5{alpha}-cholesta-7,24(28)-dien-3{beta}-ol), spinasterol (24{alpha}-ethyl-5{alpha}-cholesta-7,22-dien-3{beta}-ol), and 22-dihydrospinasterol (24{alpha}-ethyl-5{alpha}-cholest-7-en-3{beta}-ol). The major ecdysteroids biosynthesized are ecdysterone (2{beta},3{beta},14{alpha},20R,22R,25-hexahydroxy-5{beta}-cholest-7-en-6-one) and polypodine B (2{beta},3{beta},5{beta},14{alpha},20R,22R,25-heptahycroxycholest-7-en-6-one) and polypodine B (2{beta},3{beta},5{beta},14{alpha},20R,22R,25-heptahydroxycholest-7-en-6-one). When labeled 2-{sup 14}C-mevalonic acid was incorporated into young leaves isolated squalene, sterols and ecdysteroids contained the label. During a short (16 h) incorporation period in intact young leaves of 100 day old plants, the avenasterol has the highest specific activity in counts per minute per {mu}g of sterol followed by 22-dihydrospinasterol which is more highly labeled than spinasterol. The ecdysteroids synthesized, on an entire plant basis, account for 20% of the total steroid (sterol and ecdysteroid) isolated from the plant.

Grebenok, R.J.; Adler, J.H. (Michigan Technological Univ., Houghton (USA))

1990-05-01

157

Haste Makes Waste but Condition Matters: Molt Rate–Feather Quality Trade-Off in a Sedentary Songbird  

Microsoft Academic Search

BackgroundThe trade-off between current and residual reproductive values is central to life history theory, although the possible mechanisms underlying this trade-off are largely unknown. The ‘molt constraint’ hypothesis suggests that molt and plumage functionality are compromised by the preceding breeding event, yet this candidate mechanism remains insufficiently explored.Methodology\\/Principal FindingsThe seasonal change in photoperiod was manipulated to accelerate the molt rate.

Csongor I. Vágási; Péter L. Pap; Orsolya Vincze; Zoltán Benk?; Attila Marton; Zoltán Barta

2012-01-01

158

Meta-iodobenzylguanidine inhibits complex I and III of the respiratory chain in the human cell line molt-4  

Microsoft Academic Search

In this paper we report the effects of meta-iodobenzylguanidine (MIBG), a structural analogue of norepinephrine, on cell proliferation and several parameters related to mitochondrial respiration in Molt-4 cells. In micromolar concentrations, MIBG completely inhibited the proliferation of Molt-4 cells. In intact Molt-4 cells, a progressive increase in the lactate to pyruvate ratio was observed after incubation of these cells with

Jan Cornelissen; Ronald J. A. Wanders; Albert H. van Gennip; Coby van den Bogert; P. A. Voûte; André B. P. van Kuilenburg

1995-01-01

159

40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.  

Code of Federal Regulations, 2010 CFR

...Aquatic Ecosystem § 230.31 Fish, crustaceans, mollusks...variously affect populations of fish, crustaceans, mollusks...production and accumulation of toxins, or by ingestion and retention...movements of some species of fish and crustacea, thus...

2009-07-01

160

40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.  

Code of Federal Regulations, 2010 CFR

...Aquatic Ecosystem § 230.31 Fish, crustaceans, mollusks...variously affect populations of fish, crustaceans, mollusks...production and accumulation of toxins, or by ingestion and retention...movements of some species of fish and crustacea, thus...

2010-07-01

161

Cloning of a nitric oxide synthase from green shore crab, Carcinus maenas: a comparative study of the effects of eyestalk ablation on expression in the molting glands (Y-organs) of C. maenas, and blackback land crab, Gecarcinus lateralis.  

PubMed

Molting in decapod crustaceans is regulated by ecdysteroids produced by a pair of Y-organs (YOs) located in the cephalothorax. YO ecdysteroidogenesis is suppressed by molt-inhibiting hormone (MIH), a neuropeptide produced in the X-organ of the eyestalk (ES) ganglia. MIH signaling may involve nitric oxide synthase (NOS) and NO-sensitive guanylyl cyclase (GC-I). A full-length cDNA encoding Carcinus maenas NOS (Cm-NOS; 3836 base pairs) of 1164 amino acid residues (estimated mass 131,833 Da) was cloned with 88% identity to Gecarcinus lateralis NOS (Gl-NOS). End-point reverse transcription-polymerase chain reaction (RT-PCR) showed that Cm-NOS was expressed at varying levels in the YO, testis, ovary, hepatopancreas, midgut, hindgut, heart, thoracic ganglion, and skeletal muscle and was not detected in the gill. Immunofluorescence microscopy showed localization of NOS and cGMP in the steroidogenic cells and the surrounding connective tissue layer of the C. maenas YO. ES ablation (ESA) induced molting in G. lateralis; hemolymph ecdysteroid titers increased during premolt and reached a peak of about 400 pg/?L at 20 days and 24 days post-ESA. By contrast, ESA did not induce molting in C. maenas; hemolymph ecdysteroid titers increased about 2-fold (53 to 121 pg/?L) by 3 days post-ESA and remained at that level at 7 days post-ESA. Real time PCR was used to quantify the effects of ESA on the expression of NOS in C. maenas and G. lateralis YOs. ESA caused 32-fold and 5-fold increases in Gl-NOS and Cm-NOS transcripts by 24 days and 7 days post-ESA, respectively, which were correlated with hemolymph ecdysteroid levels. In addition, GC-I catalytic subunit (Gl-GC-I?) mRNA level increased 7.4-fold by 24 days post-ESA, but there was no significant effect of ESA on membrane GC (Gl-GC-II) mRNA level. These data indicate that the YO up-regulates NO signaling components in response to withdrawal of ES neuropeptides. PMID:20959144

McDonald, Audrey A; Chang, Ernest S; Mykles, Donald L

2010-10-16

162

Body condition, food habits, and molt status of late-wintering ruddy ducks in California  

USGS Publications Warehouse

We studied body condition, food habits, and molt status of late-wintering ruddy ducks (Oxyura jamaicensis) using drainwater evaporation ponds in the southern San Joaquin Valley, California. Levels of body fat and protein were similar by sex but varied by age (adults greater than immatures). Masses of breast and leg muscle protein were greatest in adult males and lowest in immature males, but similar in adult and immature females. Fat and protein levels in late-wintering ruddy ducks were independent of their body size. We detected no differences among sex-age classes in the proportion of animal foods consumed. Aquatic invertebrates composed 85% of the diet; midge larvae (Diptera: Chironomidae) and brine flies (Diptera: Ephydridae) were the principal taxa consumed. Molt score by feather region and overall molt score did not vary by sex or age. Light to moderate molt (25 to 50% molting feathers) was recorded in all feather regions. High levels of body fat and protein were attributed to premigratory hyperphagia and consumption of foods with a high protein:energy ratio.

Hohman, W. L.; Ankney, C. D.; Roster, D.L.

1992-01-01

163

Evidence for wing molt and breeding site fidelity in King Eiders  

USGS Publications Warehouse

Fidelity of King Eiders (Somateria spectabilis) to breeding and wing molt sites was examined using satellite telemetry data obtained opportunistically when battery life of transmitters provided locations in a second year. Consecutive breeding locations were obtained for eleven female and 23 male King Eiders. All females exhibited breeding site fidelity by returning to sites within 15 km of first year breeding areas on the North Slope of Alaska. Breeding locations of males in a subsequent year were located on average >1000 km from their prior breeding sites and were primarily outside Alaska, on the coasts of Russia and Canada. Second-year wing molt locations were obtained for two female and six male King Eiders. Wing molt sites of males were located 6.2 ?? 3.1 km apart on average in successive years, while female wing molt locations averaged almost 50 km apart. Our results demonstrate site fidelity of female King Eiders to a breeding area on the North Slope of Alaska, document the dispersal of male King Eiders between breeding seasons, and present the first evidence for wing molt site fidelity in males.

Phillips, L. M.; Powell, A. N.

2006-01-01

164

Relative costs of prebasic and prealternate molts for male blue-winged teal  

USGS Publications Warehouse

We compared masses of definitive basic and alternate plumages of male Blue-winged Teal (Anas discors) to evaluate the hypothesis that nutritional investments in basic and alternate plumages are related to the duration that plumages are worn and to assess the relative costs of prebasic and prealternate molts. Because these plumages are worn by males for approximately equal durations, we predicted that masses of the basic and alternate body plumages would be similar. To assess nutritional stress (demands greater than available resources) associated with molt, we examined the relation between remigial length and structural size and compared predicted and observed plum-age masses of Blue-winged Teal and other ducks. If birds were nutritionally challenged during remigial molt, then we predicted remigial length would be influenced by nutrition rather than size, and remigial length and size would be unrelated. Alternate body plumage of male Blue-winged Teal weighed about 10% more than the basic body plumage; however, masses of both plumages were less than that predicted on the basis of lean body mass. We argue that deviations between observed and predicted plumage masses were related to factors other than nutrition. Further, remigial lengths were significantly, albeit weakly, related to structural size. We therefore concluded that, although the potential for molt-induced stress may be greatest in small-bodied waterfowl species, there was no clear evidence that molting male Blue-winged Teal were nutritionally stressed. ?? The Cooper Ornithological Society 1997.

Hohman, W. L.; Manley, S. W.; Richard, D.

1997-01-01

165

OSMOTIC AND IONIC REGULATION IN THE ISOPOD CRUSTACEAN LIGIA OCEANICA  

Microsoft Academic Search

Little is known of the physiology of isopods, and although much work has been done on the osmoregulation of other crustacean groups in both marine and fresh- water environments, the isopods have been rarely studied. The occurrence of related isopod species in marine, fresh-water and terrestrial habitats should provide interesting material for comparative physiological study. Ligia oceanica (L.) is the

G. PARRY

166

The role of behavior in the success of invasive crustaceans  

Microsoft Academic Search

Many crustaceans have been moved to new locations where they have caused ecological or economic problems, that is, have become invasive. This article focuses on the role of animal behavior in contributing to their success. Certain behaviors are particularly relevant, including (1) feeding: outcompeting native species for food or eating native species of concern; (2) predator avoidance: the invader may

Judith S. Weis

2010-01-01

167

Behavioural evidence for colour vision in stomatopod crustaceans  

Microsoft Academic Search

If an organism can be taught to respond in a particular way to a wavelength of light, irrespective of that light's intensity, then it must be able to perceive the colour of the stimulus. No marine invertebrate has yet been shown to have colour vision. Stomatopod crustaceans (mantis shrimps) are colourful animals and their eyes have many adaptations which indicate

N. J. Marshall; J. P. Jones; T. W. Cronin

1996-01-01

168

Use of plant protein sources in crustacean diets  

Technology Transfer Automated Retrieval System (TEKTRAN)

World production of crustaceans has experienced a steady expansion that is expected to continue as world population increases and demand for quality sea food continues to rise. Paralleling the growth of industry has been an expansion in feed production, which has been primarily dominated by marine s...

169

Ontogenic changes of amino acid composition in planktonic crustacean species  

Microsoft Academic Search

Changes in amino acid composition (AAC) during ontogeny of some planktonic crustacean species commonly found in fresh and brackish coastal waters were compared. For these comparisons two calanoid copepods (Eurytemora velox and Calanipeda aquae-dulcis), two cyclopoid copepods (Diacyclops bicuspidatus odessanus and Acanthocyclops robustus) and two Daphnia (Daphnia pulicaria and Daphnia magna) species were selected. A discriminant analysis was performed to

Sandra Brucet; Dani Boix; Rocìo López-Flores; Anna Badosa; Xavier D. Quintana

2005-01-01

170

Non-visual functions of crustacean eyestalk ganglia  

Microsoft Academic Search

Summary Ablation experiments demonstrated that in several crustacean groups, the proximal eyestalk ganglia are important in a variety of behavior patterns:1.Chemical elicitation of feeding via the antennules is altered in lobsters, hermit crabs, and some brachyuran crabs by bilateral eyestalk ablation; the ablation of one antennule and the contralateral eyestalk is effective in lobsters and hermit crabs;2.increased chewing of inedible

Brian A. Hazlett

1971-01-01

171

IN BIODEGRADATION OF CRUSTACEAN REMAINS IN LACUSTRINE HABITATS  

Microsoft Academic Search

This study presents results of re- search on occurrence of chitinolytic bacteria and fungi in water, bottom sediments, and watershed soil of an eutrophic lake and on their ability to use the crustacean skeletons (shrimp waste) as a respi- ration substrate. It was found that the respiration rate of bacteria and fungi during decomposition of chitin varied in different environments.

Maria SWIONTEK BRZEZINSKA; Wojciech DONDERSKI

172

Sex Steroids Effects on the Molting Process of the Helminth Human Parasite Trichinella spiralis  

PubMed Central

We evaluated the in vitro effects of estradiol, progesterone, and testosterone on the molting process, which is the initial and crucial step in the development of the muscular larvae (ML or L1) to adult worm. Testosterone had no significative effect on the molting rate of the parasite, however, progesterone decreased the molting rate about a 50% in a concentration- and time-independent pattern, while estradiol had a slight effect (10%). The gene expression of caveolin-1, a specific gene used as a marker of parasite development, showed that progesterone and estradiol downregulated its expression, while protein expression was unaffected. By using flow citometry, a possible protein that is recognized by a commercial antiprogesterone receptor antibody was detected. These findings may have strong implications in the host-parasite coevolution, in the sex-associated susceptibility to this infection and could point out to possibilities to use antihormones to inhibit parasite development.

Hernandez-Bello, Romel; Ramirez-Nieto, Ricardo; Muniz-Hernandez, Sae; Nava-Castro, Karen; Pavon, Lenin; Sanchez-Acosta, Ana Gabriela; Morales-Montor, Jorge

2011-01-01

173

Sex steroids effects on the molting process of the helminth human parasite Trichinella spiralis.  

PubMed

We evaluated the in vitro effects of estradiol, progesterone, and testosterone on the molting process, which is the initial and crucial step in the development of the muscular larvae (ML or L1) to adult worm. Testosterone had no significative effect on the molting rate of the parasite, however, progesterone decreased the molting rate about a 50% in a concentration- and time-independent pattern, while estradiol had a slight effect (10%). The gene expression of caveolin-1, a specific gene used as a marker of parasite development, showed that progesterone and estradiol downregulated its expression, while protein expression was unaffected. By using flow citometry, a possible protein that is recognized by a commercial antiprogesterone receptor antibody was detected. These findings may have strong implications in the host-parasite coevolution, in the sex-associated susceptibility to this infection and could point out to possibilities to use antihormones to inhibit parasite development. PMID:22162638

Hernández-Bello, Romel; Ramirez-Nieto, Ricardo; Muñiz-Hernández, Saé; Nava-Castro, Karen; Pavón, Lenin; Sánchez-Acosta, Ana Gabriela; Morales-Montor, Jorge

2011-11-03

174

Molting of megalopae of the Asian shore crab Hemigrapsus sanguineus in intertidal habitats of Northeastern North America  

Microsoft Academic Search

Planktonic larvae of many benthic taxa settle and metamorphose in response to certain habitat cues. Although laboratory investigations of the importance of potential cues are numerous, field experiments are less common. We modified a field caging technique first developed for analysis of molting specificity of fiddler crab megalopae to test potential habitat cues affecting molting of megalopae of the non-native

Nancy J. O'Connor; Michael L. Judge

2010-01-01

175

Molted feathers from clay licks in Peru provide DNA for three large macaws ( Ara ararauna , A. chloropterus , and A. macao )  

Microsoft Academic Search

Conservation genetic analyses of wildlife have increased greatly in the past 10 yr, yet genetic studies of parrots are rare because of difficulties associated with capturing them and obtaining samples. Recent studies have demonstrated that molted feathers can provide a useful source of DNA, but success rates have varied considerably among studies. Our objective was to determine if molted macaw

Kara J. Gebhardt; Donald Brightsmith; George Powell; Lisette P. Waits

2009-01-01

176

Molting success of Ixodes scapularis varies among individual blood meal hosts and species.  

PubMed

The blacklegged tick (Ixodes scapularis) is an important vector of emerging human pathogens. It has three blood-feeding stages, as follows: larva, nymph, and adult. Owing to inefficient transovarial transmission, at least for the Lyme disease agent (Borrelia burgdorferi), larval ticks rarely hatch infected, but they can acquire infection during their larval blood meal. Nymphal ticks are primarily responsible for transmitting pathogens to hosts, including humans. The transition from uninfected host-seeking larva to infectious host-seeking nymph is therefore a key aspect of human risk of infection. It can be divided into a series of steps, as follows: finding a host, taking a blood meal, becoming infected, molting, and overwintering. The chance of succeeding in each of these steps may depend on the species identity of the blood meal host. We used a Bayesian method to estimate the molting success of larval I. scapularis collected from four commonly parasitized species of birds and eight commonly parasitized small and mid-sized mammals found in the forests of Dutchess County, New York. We show that molting success varies substantially among host species; white-footed mice, veeries, and gray catbirds support particularly high molting success, whereas ticks feeding on short-tailed shrews, robins, and wood thrushes were less successful. We also show that larval molting success varies substantially between individual blood meal hosts, and that this intraspecific variability is much higher in some species than in others. The causes of both inter- and intraspecific variation in molting success remain to be determined. PMID:21845946

Brunner, Jesse L; Cheney, Laura; Keesing, Felicia; Killilea, Mary; Logiudice, Kathleen; Previtali, Andrea; Ostfeld, Richard S

2011-07-01

177

[Effects of dimilin, a chitin inhibitor 1 (4 chlorophenyl) 3 (2-6 difluorobenzoyl) urea on the oenocytes and molting in the processionary caterpillar (Thaumetopoea pityocampa Schiff.) (Lepidoptera) (author's transl)].  

PubMed

Te oenocytes of the processionary caterpillar show histophysiological variations during their developing cycle. Grafting experiments and culture in vitro, have not so far allowed us to reveal the least participation of the oenocytes in the determinism of molting and in the transformation of cholesterol into ecdysone. On the other hand, histochemical studies of the oenocytes during the last period of their larval state, reveal, just before nymphosis, the existence of polysaccharides which probably correspond to the synthesis of pre-cuticular substance. When the caterpillars are treated with a chitin inhibitor (pH - 60-40 = Dimilin), the polysaccharides are not longer to be seen in the oenocytes. This deficiency in cuticular material could well be the consequence of one of the most spectacular effects of this product that is a profound perturbation in the formation of the cuticle that leads to the death of animals when molting. PMID:565611

Denneulin, J C; Lamy, M

1977-01-01

178

Effects of a premolt calcium and low-energy molt program on laying hen performance, egg quality, and economics.  

PubMed

The objectives of this study were to evaluate and compare the effects of production, physiology, egg quality, and economics of laying hens housed in a cage system when offered a calcium premolt treatment and low-energy molt diets versus a traditional feed withdrawal (FW) treatment during and after molt. In total, 981 Hy-Line W-36 laying hens (85 wk of age) housed 3 per cage were used. Six treatments were compared in a 2 × 3 factorial design with 2 calcium premolt treatments (fine and coarse) and 3 molt diets (FW, soybean hulls, and wheat middlings). The coarse Ca was a 50:50 mix of fine (0.14-mm mean diameter) and coarse (2.27-mm mean diameter) CaCO(3), whereas the fine Ca was an all-fine CaCO(3). Both diets were formulated to contain 4.6% Ca, such that only the particle size of the CaCO(3) differed. Production parameters in experiment 1 included egg production, egg weight and mass, specific gravity, Haugh units, egg components, feed consumption and utilization, and BW. Physiological parameters in experiment 2 included ovary and oviduct weights, femur- and humerus-ash percentages, heterophil to lymphocyte ratios, plasma Ca and inorganic P concentrations, and alkaline phosphatase activity. Data were analyzed by ANOVA and P < 0.05 was significant. The fine-Ca premolt treatment was more effective than the coarse-Ca treatment at decreasing egg production during molt and increasing it postmolt, regardless of the molt diet. The FW molt diet resulted in the greatest decrease in production, but the soybean hulls diet resulted in lower production and ovary and oviduct weights during molt compared with those of the wheat middlings molt diet. Therefore, a fine-Ca premolt treatment and a low-energy molt diet, particularly soybean hulls, can be useful alternatives to a FW molt. PMID:22252340

Dickey, E R; Johnson, A K; Stalder, K J; Bregendahl, K

2012-02-01

179

Developmental toxicity of testosterone in the crustacean Daphnia magna involves anti-ecdysteroidal activity  

Microsoft Academic Search

Testosterone has been shown to cause developmental arrest of embryonic daphnids (Daphnia magna). The present study was undertaken to determine whether this toxicity might be due to anti-ecdysteroidal activity associated with testosterone. The effect of testosterone on molt frequency of early instar daphnids was first evaluated to determine whether testosterone interfered with this ecdysteroid-regulated process. Molt frequency was delayed by

Xueyan Mu; Gerald A LeBlanc

2002-01-01

180

Ultrahistochemical localization of Na+?K+ ATPase, Ca2+ATPase and alkaline phosphatase activity in a calcium-transporting epithelium of a crustacean during moulting  

Microsoft Academic Search

Periodical changes in Na+-K+-ATPase, Ca2+-ATPase and non-specific alkaline-phosphatase activity were observed using cytochemical techniques in the posterior caeca of the crustacean amphipod, Orchestia cavimana, during the moult cycle. These changes were considered in relation to the calcium transport mechanisms in the posterior caecal epithelium. For both ATPases as well as alkaline phosphatase, the specific reaction products were most intense during

J. C. Meyran; F. Graf

1986-01-01

181

Annual survival and site fidelity of Stellar's Eiders molting along the Alaska Peninsula  

USGS Publications Warehouse

Populations of Steller?s eiders (Polysticta stelleri) molting and wintering along the Alaska Peninsula have declined since the 1960's. We captured and marked a large sample of Steller's eiders molting in 2 lagoons along the Alaska Peninsula between 1975-97. We used mark-recapture analysis techniques to estimate annual survival and movement probabilities within and among lagoons for male and female eiders. Estimates of annual survival (?SE) were 0.899 ? 0.032 for females and 0.765 ? 0.044 for males. Both sexes showed high rates of fidelity to specific molting locations (>95%) within lagoons; yet we found no evidence that annual probability of survival differed among groups molting in different locations either within or among lagoons. We found weak evidence that annual survival decreased between the periods 1975-81 and 1991-97. The lower survival of males compared to females is unusual for waterfowl and may result in a female-biased sex ratio. We conclude that a decrease in adult survival may have initiated the long-term population decline. Further, a shortage of males may be limiting reproductive potential.

Flint, P.L.; Petersen, M.R.; Dau, C.P.; Hines, J.E.; Nichols, J.D.

2000-01-01

182

Effect of vitamins, probiotics and protein on semen traits in post-molt male broiler breeders.  

PubMed

The study aimed to investigate the comparative effect of vitamins E and C, probiotics, lower than normal protein level and the combination of these treatments in male broiler breeders after Zn-induced molting. One hundred and eighty birds at 65 weeks of age were divided into six groups (five replicates per group) in a completely randomized block design. Birds were induced to molt by mixing zinc oxide in feed at the rate of 3000 mg/kg of feed. Upon completion of molting, birds were fed different supplements. One group was kept as a control, while the other groups were fed: vitamin E (100 IU/kg), vitamin C (500 IU/kg), probiotics (50 mg/L of water), lower dietary protein level (14%) or the combination of these treatments. Results revealed that vitamins (E and C) supplementation increased (P<0.05) semen volume, however, sperm motility and egg fertility were significantly higher only in vitamin E supplemented group compared to control. The dead sperm percentage decreased (P<0.05) in vitamin C fed group, whereas, sperm concentration did not differ (P>0.05) between the control and treated groups. The results validate the key role of antioxidant vitamins in male broiler breeders' fertility after Zn-induced molting. PMID:23078867

Khan, R U; Rahman, Zia-ur; Javed, I; Muhammad, F

2012-09-26

183

Entomogenous fungus Nomuraea rileyi inhibits host insect molting by C22-oxidizing inactivation of hemolymph ecdysteroids.  

PubMed

The entomogenous fungus Nomuraea rileyi reportedly secretes a proteinaceous substance inhibiting larval molt and metamorphosis in the silkworm Bombyx mori. We studied the possibility that N. rileyi controls B. mori development by inactivating hemolymph molting hormone, ecdysteroids. Incubation of ecdysone (E) and 20-hydroxyecdysone (20E) in fungal-conditioned medium resulted in their rapid modification into products with longer retention times in reverse-phase HPLC. Each modified product from E and 20E was purified by HPLC, and identified by NMR as 22-dehydroecdysone and 22-dehydro-20-hydroxyecdysone. Some other ecdysteroids with a hydroxyl group at position C22 were also modified. Injection of the fungal-conditioned medium into Bombyx mori larvae in the mid-4th instar inhibited larval molt but induced precocious pupal metamorphosis, and its injection into 5th instar larvae just after gut purge blocked pupal metamorphosis. In hemolymph of injected larvae, E and 20E disappeared and, in turn, 22-dehydroecdysone and 22-dehydro-20-hydroxyecdysone accumulated. These results indicate that N. rileyi secretes a specific enzyme that oxidizes the hydroxyl group at position C22 of hemolymph ecdysteroids and prevents molting in B. mori larvae. PMID:12489132

Kiuchi, Makoto; Yasui, Hiroe; Hayasaka, Shoji; Kamimura, Manabu

2003-01-01

184

DISCRIMINATION OF CONSPECIFIC MALE MOLT ODOR SIGNALS BY MALE CRAYFISH, ORCONECTES RUSTICUS  

Microsoft Academic Search

For many organisms, chemoreception plays a key role in numerous aspects of daily life. Crayfish use chemical signals to find mates, warn conspecifics of predators, and relay social status. While many of these situations have been studied in detail, behavior of conspecifics toward chemical signals from molted individuals has not been thoroughly examined. The physiology of crayfish changes dramatically during

Julie A. Adams; Paul A. Moore

2003-01-01

185

Influence of extracts of adult crabs on molting of fiddler crab megalopae ( Uca pugnax )  

Microsoft Academic Search

Larvae of many benthic invertebrates metamorphose in response to habitat cues, which include the presence of adult conspecifics. Prior research showed that fiddler crab [Uca pugnax (Smith)] megalopae advance molting to the first crab stage in seawater in which conspecific adult crabs were maintained. In the present study, extracts of adult crabs were prepared and the specificity and protein content

N. J. O’Connor

2005-01-01

186

The Gastrointestinal Tract Ecology of Salmonella Enteritidis Colonization in Molting Hens  

Microsoft Academic Search

There is an interaction between feed with- drawal induced-molting and foodborne Salmonella Enter- itidis colonization and invasion in susceptible laying hens. Less is known about the ecology of the indigenous microflora and their response to feed removal, the re- sponse of S. Enteritidis to feed removal (virulence expres- sion), and the interaction between the gastrointestinal tract microenvironment and S. Enteritidis.

S. C. Ricke

187

LINOLEIC AND LINOLELAIDIC ACIDS DIFFERENTIALLY INFLUENCE PROLIFERATION AND APOPTOSIS OF MOLT4 LEUKAEMIA CELLS  

Microsoft Academic Search

The effects of varying concentrations of linoleic acid and its transisomer linolelaidic acid on the proliferation the ultrastructural morphology of MOLT-4 T-lymphoblastic leukaemia cells were investigated. At 2 and 4 days after exposure to the fatty acids, the cells were counted by flow cytometry and observed by electron microscopy. After 4 days of treatment, linoleic acid was growth stimulatory at

M. C. Phoon; Charles Desbordes; J. Howe; Vincent T. K. Chow

2001-01-01

188

Demecology in the Cambrian: synchronized molting in arthropods from the Burgess Shale  

PubMed Central

Background The Burgess Shale is well known for its preservation of a diverse soft-bodied biota dating from the Cambrian period (Series 3, Stage 5). While previous paleoecological studies have focused on particular species (autecology) or entire paleocommunities (synecology), studies on the ecology of populations (demecology) of Burgess Shale organisms have remained mainly anecdotal. Results Here, we present evidence for mass molting events in two unrelated arthropods from the Burgess Shale Walcott Quarry, Canadaspis perfecta and a megacheiran referred to as Alalcomenaeus sp. Conclusions These findings suggest that the triggers for such supposed synchronized molting appeared early on during the Cambrian radiation, and synchronized molting in the Cambrian may have had similar functions in the past as it does today. In addition, the finding of numerous juvenile Alalcomenaeus sp. molts associated with the putative alga Dictyophycus suggests a possible nursery habitat. In this nursery habitat a population of this animal might have found a more protected environment in which to spend critical developmental phases, as do many modern species today.

2013-01-01

189

Phylogenetic position of the Pentastomida and (pan)crustacean relationships.  

PubMed

Pentastomids are a small group of vermiform animals with unique morphology and parasitic lifestyle. They are generally recognized as being related to the Arthropoda; however, the nature of this relationship is controversial. We have determined the complete sequence of the mitochondrial DNA (mtDNA) of the pentastomid Armillifer armillatus and complete or nearly complete mtDNA sequences from representatives of four previously unsampled groups of Crustacea: Remipedia (Speleonectes tulumensis), Cephalocarida (Hutchinsoniella macracantha), Cirripedia (Pollicipes polymerus) and Branchiura (Argulus americanus). Analyses of the mtDNA gene arrangements and sequences determined in this study indicate unambiguously that pentastomids are a group of modified crustaceans probably related to branchiurans. In addition, gene arrangement comparisons strongly support an unforeseen assemblage of pentastomids with maxillopod and cephalocarid crustaceans, to the exclusion of remipedes, branchiopods, malacostracans and hexapods. PMID:15129965

Lavrov, Dennis V; Brown, Wesley M; Boore, Jeffrey L

2004-03-01

190

Phylogenetic position of the pentastomida and [pan]crustacean relationships  

SciTech Connect

Pentastomids are a small group of vermiform animals with unique morphology and parasitic lifestyle. They are generally recognized as being related to the Arthropoda, however the nature of this relationship is controversial. We have determined the complete sequence of the mitochondrial DNA (mtDNA) of the pentastomid Armillifer armillatus and complete, or nearly complete, mtDNA sequences from representatives of four previously unsampled groups of Crustacea: Remipedia (Speleonectes tulumensis), Cephalocarida (Hutchinsoniella macracantha), Cirripedia (Pollicipes polymerus), and Branchiura (Argulus americanus). Analyses of the mtDNA gene arrangements and sequences determined in this study indicate unambiguously that pentastomids are a group of modified crustaceans likely related to branchiurans. In addition, gene arrangement comparisons strongly support an unforeseen assemblage of pentastomids with maxillopod and cephalocarid crustaceans, to the exclusion of remipedes, branchiopods, malacos tracans and insects.

Lavrov, Dennis V.; Brown, Wesley M.; Boore, Jeffrey L.

2004-01-31

191

"Population dynamics of crustaceans": introduction to the symposium.  

PubMed

Crustaceans are a globally-distributed faunal group, found across all habitats from the equator to the poles. They are an ideal focal assemblage for assessment of the impacts of climatic change and anthropogenic disturbance on nonmodel systems, such as how sea currents influence the movements of zooplankton communities in the open ocean, or how ecosystem processes affect phytoplanktonic species with restricted geographic distributions across a cluster of island lakes that could be a new model system for studies of speciation. This symposium introduced early-career researchers working in the fields of phylogeography, ecogenomics, fisheries management, and ecosystem processes with the aim of highlighting the different genetic and ecological approaches to the study of population dynamics of freshwater, estuarine, and marine crustacean species. PMID:21856734

Buhay, Jennifer E

2011-08-19

192

Daphnia Halloween genes that encode cytochrome P450s mediating the synthesis of the arthropod molting hormone: Evolutionary implications  

Microsoft Academic Search

BACKGROUND: In crustaceans and insects, development and reproduction are controlled by the steroid hormone, 20-hydroxyecdysone (20E). Like other steroids, 20E, is synthesized from cholesterol through reactions involving cytochrome P450s (CYPs). In insects, the CYP enzymes mediating 20E biosynthesis have been identified, but evidence of their probable presence in crustaceans is indirect, relying solely on the ability of crustaceans to synthesize

Kim F Rewitz; Lawrence I Gilbert

2008-01-01

193

Mitochondrial genomes suggest that hexapods and crustaceans are mutually paraphyletic  

PubMed Central

For over a century the relationships between the four major groups of the phylum Arthropoda (Chelicerata, Crustacea, Hexapoda and Myriapoda) have been debated. Recent molecular evidence has confirmed a close relationship between the Crustacea and the Hexapoda, and has included the suggestion of a paraphyletic Hexapoda. To test this hypothesis we have sequenced the complete or near-complete mitochondrial genomes of three crustaceans (Parhyale hawaiensis, Squilla mantis and Triops longicaudatus), two collembolans (Onychiurus orientalis and Podura aquatica) and the insect Thermobia domestica. We observed rearrangement of transfer RNA genes only in O. orientalis, P. aquatica and P. hawaiensis. Of these, only the rearrangement in O. orientalis, an apparent autapomorphy for the collembolan family Onychiuridae, was phylogenetically informative. We aligned the nuclear and amino acid sequences from the mitochondrial protein-encoding genes of these taxa with their homologues from other arthropod taxa for phylogenetic analysis. Our dataset contains many more Crustacea than previous molecular phylogenetic analyses of the arthropods. Neighbour-joining, maximum-likelihood and Bayesian posterior probabilities all suggest that crustaceans and hexapods are mutually paraphyletic. A crustacean clade of Malacostraca and Branchiopoda emerges as sister to the Insecta sensu stricto and the Collembola group with the maxillopod crustaceans. Some, but not all, analyses strongly support this mutual paraphyly but statistical tests do not reject the null hypotheses of a monophyletic Hexapoda or a monophyletic Crustacea. The dual monophyly of the Hexapoda and Crustacea has rarely been questioned in recent years but the idea of both groups' paraphyly dates back to the nineteenth century. We suggest that the mutual paraphyly of both groups should seriously be considered.

Cook, Charles E; Yue, Qiaoyun; Akam, Michael

2005-01-01

194

Bacteria-Induced Dscam Isoforms of the Crustacean, Pacifastacus leniusculus  

Microsoft Academic Search

The Down syndrome cell adhesion molecule, also known as Dscam, is a member of the immunoglobulin super family. Dscam plays an essential function in neuronal wiring and appears to be involved in innate immune reactions in insects. The deduced amino acid sequence of Dscam in the crustacean Pacifastacus leniusculus (PlDscam), encodes 9(Ig)-4(FNIII)-(Ig)-2(FNIII)-TM and it has variable regions in the N-terminal

Apiruck Watthanasurorot; Pikul Jiravanichpaisal; Haipeng Liu; Irene Söderhäll; Kenneth Söderhäll

2011-01-01

195

Mitochondrial genomes suggest that hexapods and crustaceans are mutually paraphyletic.  

PubMed

For over a century the relationships between the four major groups of the phylum Arthropoda (Chelicerata, Crustacea, Hexapoda and Myriapoda) have been debated. Recent molecular evidence has confirmed a close relationship between the Crustacea and the Hexapoda, and has included the suggestion of a paraphyletic Hexapoda. To test this hypothesis we have sequenced the complete or near-complete mitochondrial genomes of three crustaceans (Parhyale hawaiensis, Squilla mantis and Triops longicaudatus), two collembolans (Onychiurus orientalis and Podura aquatica) and the insect Thermobia domestica. We observed rearrangement of transfer RNA genes only in O. orientalis, P. aquatica and P. hawaiensis. Of these, only the rearrangement in O. orientalis, an apparent autapomorphy for the collembolan family Onychiuridae, was phylogenetically informative.We aligned the nuclear and amino acid sequences from the mitochondrial protein-encoding genes of these taxa with their homologues from other arthropod taxa for phylogenetic analysis. Our dataset contains many more Crustacea than previous molecular phylogenetic analyses of the arthropods. Neighbour-joining, maximum-likelihood and Bayesian posterior probabilities all suggest that crustaceans and hexapods are mutually paraphyletic. A crustacean clade of Malacostraca and Branchiopoda emerges as sister to the Insecta sensu stricto and the Collembola group with the maxillopod crustaceans. Some, but not all, analyses strongly support this mutual paraphyly but statistical tests do not reject the null hypotheses of a monophyletic Hexapoda or a monophyletic Crustacea. The dual monophyly of the Hexapoda and Crustacea has rarely been questioned in recent years but the idea of both groups' paraphyly dates back to the nineteenth century. We suggest that the mutual paraphyly of both groups should seriously be considered. PMID:16024395

Cook, Charles E; Yue, Qiaoyun; Akam, Michael

2005-06-22

196

Consequences of Prairie Wetland Drainage for Crustacean Biodiversity and Metapopulations  

Microsoft Academic Search

Much of Illinois was once wet prairie, dotted with ancient (ca. 10,000-year-old) ephemeral wet- lands. Most wetland habitat (85%) was converted to agriculture over a span of about 100 years (ca. 1850- 1950). The consequences of this severe habitat fragmentation on wetland communities and metapopulations are unknown. We studied crustacean communities (weekly stovepipe samples throughout hydroperiods) for 3 years in

David G. Jenkins; Scott Grissom; Keith Miller

2003-01-01

197

Global diversity of Isopod crustaceans (Crustacea; Isopoda) in freshwater  

Microsoft Academic Search

The isopod crustaceans are diverse both morphologically and in described species numbers. Nearly 950 described species (?9%\\u000a of all isopods) live in continental waters, and possibly 1,400 species remain undescribed. The high frequency of cryptic species\\u000a suggests that these figures are underestimates. Several major freshwater taxa have ancient biogeographic patterns dating from\\u000a the division of the continents into Laurasia (Asellidae,

George D. F. Wilson

2008-01-01

198

Global diversity of Isopod crustaceans (Crustacea; Isopoda) in freshwater  

Microsoft Academic Search

The isopod crustaceans are diverse both morphologically and in described species numbers. Nearly 950 described species (~\\u000a 9% of all isopods) live in continental waters, and possibly 1,400 species remain undescribed. The high frequency of cryptic\\u000a species suggests that these figures are underestimates. Several major freshwater taxa have ancient biogeographic patterns\\u000a dating from the division of the continents into Laurasia

George D. F. Wilson

199

Photoinduced Toxicity of Fluoranthene to Seven Marine Benthic Crustaceans  

Microsoft Academic Search

.   Seven marine benthic crustaceans were exposed in 4 d water-only toxicity tests to five concentrations of fluoranthene. After\\u000a exposures, mortality (LC50) and the ability to bury in clean sediment (EC50) were determined. Survivors were then exposed to UV radiation for 1 h. The differences between LC50s and EC50s before and after UV exposure were used to assess photoinduced toxicity.

B. L. Boese; J. O. Lamberson; R. C. Swartz; R. J. Ozretich

1997-01-01

200

Molecular cloning and expression patterns of the molt-regulating transcription factor HHR3 from Helicoverpa armigera.  

PubMed

Molt-regulating transcription factors, hormone receptor 3 (HR3), play important roles in regulating expression of tissue-specific genes involved in insect molting and metamorphosis. A 1668 bp cDNA encoding a molt-regulating transcription factor (HHR3) was cloned from Helicoverpa armigera, which encodes a protein made up of 556 amino acids. This 62 kDa protein was found to have an isoelectric point (pI) of 6.52. There was no signal peptide or N-glycosylation site found in this cDNA. A DNA-binding region signature of nuclear hormone receptor was found from amino acids 107-133. A possible outside to inside transmembrane helice was found from amino acids 72-90. Northern blots of the larvae revealed five bands of HHR3 named as band 0, 1, 2, 3 and 4 with molecular masses determined as 2.1, 2.6, 3.6, 4.5 and 5.5 kb, respectively. The expression patterns of HHR3 in vivo were variable with developmental stages and tissues. Results showed that band 1-4 of HHR3 was only briefly expressed during molting, which suggested these bands are involved in the regulation of molting cascade, whereas band 0 was expressed in both molting and feeding larvae. Band 1 and 2 of HHR3 could be induced from epidermis of newly molted 6th instar larvae by non-steroidal ecdysone agonist, RH-2485. PMID:15271213

Zhao, X-F; Wang, J-X; Xu, X-L; Li, Z-M; Kang, C-J

2004-08-01

201

Effect of novel dinuclear platinum(II) complexes on redox status of MOLT-4 leukemic cells.  

PubMed

Abstract As the alkylating agents metabolism is accompanied by reactive oxygen species (ROS) generation, the aim of this study has been to compare the effect of cisplatin and novel platinum(II) complexes, Pt2(isopropylamine)4(berenil)2, Pt2(piperazine)4(berenil)2, Pt2(2-picoline)4(berenil)2, Pt2(3-picoline)4(berenil)2, Pt2(4-picoline)4(berenil)2, on the redox state of human leukemic T-cells line Molt-4. Treatment of Molt-4 with the novel complexes has shown that all compounds enhance total ROS and superoxide anion generation as well as change the activity of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. Moreover, all the above-mentioned compounds cause a decrease in the level of non-enzymatic antioxidants such as GSH as well as vitamin C, E and A. Such a situation is conducive to oxidative stress formation and oxidative modifications of cellular macromolecules. DNA damage of MOLT-4 leukemic cells is connected with 8-hydroxy-2'-deoxyguanosine and N7-methyldeoxyguanosine generation. The increased level of protein carbonyl groups and dityrosine indicates enhanced protein oxidative modifications, while an increase in the level of lipid peroxidation products, MDA, 4-HNE and isoprostanes proves the significant lipid peroxidation after treatment of Molt-4 cells with the complexes. Moreover, the complexes enhance expression of Bax and cytochrome c as well as decrease the expression of Bcl-2 and p53 protein. The novel platinum(II) complexes in comparison with cisplatin disturb redox status more intensively and lead to oxidative stress in Molt-4 cells. The enhanced oxidative modifications of macromolecules of human leukemic cancer cells lead to a shift in the proapoptotic-antiapoptotic balance into the proapoptotic direction. PMID:23859055

Jarocka, Iwona; G?gotek, Agnieszka; Bielawska, Anna; Bielawski, Krzysztof; Luczaj, Wojciech; Hodun, Tomasz; Skrzydlewska, El?bieta

2013-08-12

202

Immunolocalisation of crustacean-SIFamide in the median brain and eyestalk neuropils of the marbled crayfish  

Microsoft Academic Search

Crustacean-SIFamide (GYRKPPFNGSIFamide) is a novel neuropeptide that was recently isolated from crayfish nervous tissue. We\\u000a mapped the localisation of this peptide in the median brain and eyestalk neuropils of the marbled crayfish (Marmorkrebs),\\u000a a parthenogenetic crustacean. Our experiments showed that crustacean-SIFamide is strongly expressed in all major compartments\\u000a of the crayfish brain, including all three optic neuropils, the lateral protocerebrum

M. A. Polanska; A. Yasuda; S. Harzsch

2007-01-01

203

Endocrine regulation of the reproduction in crustaceans: Identification of potential targets for toxicants and environmental contaminants  

Microsoft Academic Search

Progress in ecotoxicological research documents that crustaceans are highly vulnerable to diverse chemicals and toxicants\\u000a in the environment. In particular, pollutants affecting endocrine homeostasis in crustaceans (i.e., endocrine disruptors)\\u000a are intensively studied, and serious reproductive disorders have been documented. In this review, current knowledge about\\u000a the endocrine regulation of the crustacean reproduction is put together with the published ecotoxicological data

Edita Mazurová; Klára Hilscherová; Rita Triebskorn; Heinz-R. Köhler; Blahoslav Maršálek; Lud?k Bláha

2008-01-01

204

Ecdysteriod titers during the molt cycle of the blue crab resemble those of other crustacea  

SciTech Connect

Callinectes sapidus is the only true crab (brachyuran) whose pattern of ecdysteroid titers has been described as departing from the pattern seen in other decapods. While ecdysteroids in other crabs reach a peak just prior to ecdysis, those of C. sapidus were claimed to reach their maxima after ecdysis. The data reported here challenge these findings. Ecdysteroids were measured in hemolymph, ovaries, and whole animal extracts of blue crabs using a radioimmunoassay. In hemolymph and whole animals, ecdysteroid levels rose during premolt to a maximum at stage D/sub 3/. Ecdysteroids declined rapidly from late premolt stage D/sub 4/ through postmolt stage A/sub 2/, increased slightly at postmolt stage B, and returned to low levels where they remained during intermolt stage C. Ecdysteroid levels in males and immature females were not significantly different but mature females, having reached a terminal anecdysis, had signifincatly lower ecdysteroid levels. Ovaries of mature females accumulated ecdysteroids during vitellogenesis while the concentration of ecdysteroids in hemolymph was low.

Soumoff, C.; Skinner, D.M.

1983-08-01

205

Dissociation of Circadian and Circatidal Timekeeping in the Marine Crustacean Eurydice pulchra  

PubMed Central

Summary Background Tidal (12.4 hr) cycles of behavior and physiology adapt intertidal organisms to temporally complex coastal environments, yet their underlying mechanism is unknown. However, the very existence of an independent “circatidal” clock has been disputed, and it has been argued that tidal rhythms arise as a submultiple of a circadian clock, operating in dual oscillators whose outputs are held in antiphase i.e., ?12.4 hr apart. Results We demonstrate that the intertidal crustacean Eurydice pulchra (Leach) exhibits robust tidal cycles of swimming in parallel to circadian (24 hr) rhythms in behavioral, physiological and molecular phenotypes. Importantly, ?12.4 hr cycles of swimming are sustained in constant conditions, they can be entrained by suitable stimuli, and they are temperature compensated, thereby meeting the three criteria that define a biological clock. Unexpectedly, tidal rhythms (like circadian rhythms) are sensitive to pharmacological inhibition of Casein kinase 1, suggesting the possibility of shared clock substrates. However, cloning the canonical circadian genes of E. pulchra to provide molecular markers of circadian timing and also reagents to disrupt it by RNAi revealed that environmental and molecular manipulations that confound circadian timing do not affect tidal timing. Thus, competent circadian timing is neither an inevitable nor necessary element of tidal timekeeping. Conclusions We demonstrate that tidal rhythms are driven by a dedicated circatidal pacemaker that is distinct from the circadian system of E. pulchra, thereby resolving a long-standing debate regarding the nature of the circatidal mechanism.

Zhang, Lin; Hastings, Michael H.; Green, Edward W.; Tauber, Eran; Sladek, Martin; Webster, Simon G.; Kyriacou, Charalambos P.; Wilcockson, David C.

2013-01-01

206

The First Complete Mitochondrial Genome Sequences for Stomatopod Crustaceans: Implications for Phylogeny  

SciTech Connect

We report the first complete mitochondrial genome sequences of stomatopods and compare their features to each other and to those of other crustaceans. Phylogenetic analyses of the concatenated mitochondrial protein-coding sequences were used to explore relationships within the Stomatopoda, within the malacostracan crustaceans, and among crustaceans and insects. Although these analyses support the monophyly of both Malacostraca and, within it, Stomatopoda, it also confirms the view of a paraphyletic Crustacea, with Malacostraca being more closely related to insects than to the branchiopod crustaceans.

Swinstrom, Kirsten; Caldwell, Roy; Fourcade, H. Matthew; Boore, Jeffrey L.

2005-09-07

207

Metamorphosis in the cirripede crustacean Balanus amphitrite.  

PubMed

Stalked and acorn barnacles (Cirripedia Thoracica) have a complex life cycle that includes a free-swimming nauplius larva, a cypris larva and a permanently attached sessile juvenile and adult barnacle. The barnacle cyprid is among the most highly specialized of marine invertebrate larvae and its settlement biology has been intensively studied. By contrast, surprisingly few papers have dealt with the critical series of metamorphic events from cementation of the cyprid to the substratum until the appearance of a suspension feeding juvenile. This metamorphosis is both ontogenetically complex and critical to the survival of the barnacle. Here we use video microscopy to present a timeline and description of morphological events from settled cyprid to juvenile barnacle in the model species Balanus amphitrite, representing an important step towards both a broader understanding of the settlement ecology of this species and a platform for studying the factors that control its metamorphosis. Metamorphosis in B. amphitrite involves a complex sequence of events: cementation, epidermis separation from the cypris cuticle, degeneration of cypris musculature, rotation of the thorax inside the mantle cavity, building of the juvenile musculature, contraction of antennular muscles, raising of the body, shedding of the cypris cuticle, shell plate and basis formation and, possibly, a further moult to become a suspension feeding barnacle. We compare these events with developmental information from other barnacle species and discuss them in the framework of barnacle settlement ecology. PMID:22666355

Maruzzo, Diego; Aldred, Nick; Clare, Anthony S; Høeg, Jens T

2012-05-30

208

Mechanistic mathematical modelling of mercaptopurine effects on cell cycle of human acute lymphoblastic leukaemia cells  

Microsoft Academic Search

The antimetabolite mercaptopurine (MP) is widely used to treat childhood acute lymphoblastic leukaemia (ALL). To study the dynamics of MP on the cell cycle, we incubated human T-cell leukaemia cell lines (Molt-4 sensitive and resistant subline and P12 resistant) with 10 ?M MP and measured total cell count, cell cycle distribution, percent viable, percent apoptotic, and percent dead cells serially

J C Panetta; W E Evans; M H Cheok

2006-01-01

209

Molt-inhibiting hormone stimulates vitellogenesis at advanced ovarian developmental stages in the female blue crab, Callinectes sapidus 2: novel specific binding sites in hepatopancreas and cAMP as a second messenger  

PubMed Central

The finding that molt-inhibiting hormone (MIH) regulates vitellogenesis in the hepatopancreas of mature Callinectes sapidus females, raised the need for the characterization of its mode of action. Using classical radioligand binding assays, we located specific, saturable, and non-cooperative binding sites for MIH in the Y-organs of juveniles (J-YO) and in the hepatopancreas of vitellogenic adult females. MIH binding to the hepatopancreas membranes had an affinity 77 times lower than that of juvenile YO membranes (KD values: 3.22 × 10-8 and 4.19 × 10-10 M/mg protein, respectively). The number of maximum binding sites (BMAX) was approximately two times higher in the hepatopancreas than in the YO (BMAX values: 9.24 × 10-9 and 4.8 × 10-9 M/mg protein, respectively). Furthermore, MIH binding site number in the hepatopancreas was dependent on ovarian stage and was twice as high at stage 3 than at stages 2 and 1. SDS-PAGE separation of [125I] MIH or [125I] crustacean hyperglycemic hormone (CHH) crosslinked to the specific binding sites in the membranes of the J-YO and hepatopancreas suggests a molecular weight of ~51 kDa for a MIH receptor in both tissues and a molecular weight of ~61 kDa for a CHH receptor in the hepatopancreas. The use of an in vitro incubation of hepatopancreas fragments suggests that MIH probably utilizes cAMP as a second messenger in this tissue, as cAMP levels increased in response to MIH. Additionally, 8-Bromo-cAMP mimicked the effects of MIH on vitellogenin (VtG) mRNA and heterogeneous nuclear (hn) VtG RNA levels. The results imply that the functions of MIH in the regulation of molt and vitellogenesis are mediated through tissue specific receptors with different kinetics and signal transduction. MIH ability to regulate vitellogenesis is associated with the appearance of MIH specific membrane binding sites in the hepatopancreas upon pubertal/final molt.

Zmora, Nilli; Sagi, Amir; Zohar, Yonathan; Chung, J Sook

2009-01-01

210

Oxygen Consumption Rates and Oxygen Concentration in Molt4 Cells and Their mtDNA Depleted ( ? 0) Mutants  

Microsoft Academic Search

Respiratory deficient cell lines are being increasingly used to elucidate the role of mitochondria and to understand the pathophysiology of mitochondrial genetic disease. We have investigated the oxygen consumption rates and oxygen concentration in wild-type (WT) and mitochondrial DNA (mtDNA) depleted (?0) Molt-4 cells. Wild-type Molt-4 cells have moderate oxygen consumption rates, which were significantly reduced in the ?0 cells.

Jiangang Shen; Nadeem Khan; Lionel D. Lewis; Ray Armand; Oleg Grinberg; Eugene Demidenko; Harold Swartz

2003-01-01

211

A molecular genetic approach to the biosynthesis of the insect steroid molting hormone.  

PubMed

Insect growth, development, and molting depend upon a critical titer of the principal molting hormone of arthropods, 20-hydroxyecdysone (20E). Although the structure of 20E as a polyhydroxylated steroid was determined more than five decades ago, the exact steps in its biosynthesis have eluded identification. Over the past several years, the use of the fly database and the techniques and paradigms of biochemistry, analytical chemistry, and molecular genetics have allowed the cloning and sequencing of four genes in the Halloween gene family of Drosophila melanogaster, all of them encoding cytochrome P450 (CYP) enzymes, each of which mediates one of the four terminal hydroxylation steps in 20E biosynthesis. Further, the sequence of these hydroxylations has been determined, and developmental alterations in the expression of each of these genes have been quantified during both embryonic and postembryonic life. PMID:16399407

Gilbert, Lawrence I; Warren, James T

2005-01-01

212

Effect of gamma radiation on membrane fluidity of MOLT-4 nuclei  

SciTech Connect

These experiments measured the effect of gamma radiation on the nuclear envelope using doxyl-fatty acid spin-label probes. Nuclei were isolated from cultured MOLT-4 cells, a radiation-sensitive human T-cell lymphocyte. Membrane fluidity was measured from the electron paramagnetic resonance spectra of the probes. MOLT-4 cells were grown under standard conditions, and suspension were exposed to CO radiation at room temperature. The spectra of 5-doxylstearic acid in the nuclei were those of a strongly immobilized label. A difference in the membrane fluidity was detected in a series of experiments comparing labeled irradiated and nonirradiated nuclei. The change in fluidity was measured by comparing the changes in the order parameter, S, of the spin label in irradiated nuclei with those in control nuclei.

McClain, D.E.; Trypus, C.A.; May, L.

1990-01-01

213

Adult neurogenesis in the decapod crustacean brain: a hematopoietic connection?  

PubMed

New neurons are produced and integrated into circuits in the adult brains of many organisms, including crustaceans. In some crustacean species, the first-generation neuronal precursors reside in a niche exhibiting characteristics analogous to mammalian neurogenic niches. However, unlike mammalian niches where several generations of neuronal precursors co-exist, the lineage of precursor cells in crayfish is spatially separated allowing the influence of environmental and endogenous regulators on specific generations in the neuronal precursor lineage to be defined. Experiments also demonstrate that the first-generation neuronal precursors in the crayfish Procambarus clarkii are not self-renewing. A source external to the neurogenic niche must therefore provide cells that replenish the first-generation precursor pool, because although these cells divide and produce a continuous efflux of second-generation cells from the niche, the population of first-generation niche precursors is not diminished with growth and aging. In vitro studies show that cells extracted from the hemolymph, but not other tissues, are attracted to and incorporated into the neurogenic niche, a phenomenon that appears to involve serotonergic mechanisms. We propose that, in crayfish, the hematopoietic system may be a source of cells that replenish the niche cell pool. These and other studies reviewed here establish decapod crustaceans as model systems in which the processes underlying adult neurogenesis, such as stem cell origins and transformation, can be readily explored. Studies in diverse species where adult neurogenesis occurs will result in a broader understanding of fundamental mechanisms and how evolutionary processes may have shaped the vertebrate/mammalian condition. PMID:21929622

Beltz, Barbara S; Zhang, Yi; Benton, Jeanne L; Sandeman, David C

2011-09-01

214

The impact of pathogens on exploited populations of decapod crustaceans.  

PubMed

Several crustacean fisheries have experienced significant outbreaks of disease that have damaged their industries. Not only do fisheries suffer from direct losses to pathogens, such as disease-induced mortalities or reduced product value, but they can also incur indirect losses such as stunting, castration, and increased risk of predation. In some cases, the indirect losses can be substantial, yet they are often overlooked by the fishing industry as their primary focus is on recruits to the fishery, and not on the affected juvenile pre-recruits. Low levels of pathogens are to be expected in natural populations of commercial species, but baseline data on the prevalence and intensity of even the most common agents is often lacking. It is important to establish baselines for two reasons. First, it is important to know what pathogens exist in heavily exploited populations so as to gauge their potential to damage the industry; and second, during outbreaks, it is important to know whether an outbreak is a newly emergent event or whether it is a component of a cyclical phenomenon. Pathogens frequently act in concert with environmental stressors, and a variety of stressors have contributed to outbreaks of emerging agents in crustacean fisheries. Pollution, poor water quality, hypoxia, temperature extremes, and overexploitation have all been implicated as stressors in various outbreaks. This review focuses on epidemic diseases of commercially fished crustaceans. Outbreaks in cultured stocks are not covered. Disease epizootics have occurred in fished populations of crayfish and shrimp but they are less well known than the issues arising from extensive aquaculture of these species. PMID:22434001

Shields, Jeffrey D

2012-03-14

215

Immunohistochemical localization and morphometry of somatotrophs and lactotrophs in protein, probiotic and symbiotic supplemented molted layers.  

PubMed

Two-hundred Single Comb White Leg-Horn spent hens at the age of 70 weeks were purchased from a commercial layer farm. The birds were shifted to the Poultry Research Station, Department of Physiology and Pharmacology, University of Agriculture, Faisalabad, Pakistan. High dietary zinc (3g/kg feed/day) was used to induce molting in all the birds after one week of acclimatization. Thereafter, birds were divided in groups of 50 birds each, with the following treatments: G1 [control; crude protein (CP)16%, no other supplement], G2 (CP18%, no other supplement), G3 (CP16%, Symbiotic, 85 mg/L drinking water) and G4 (CP16%, Probiotic, 85mg/L in drinking water). Fifteen birds were slaughtered at 5% of peak of production each to collect their pituitary glands. The better egg production was seen in all the supplemented groups as compared to the control. Especially an earlier post molt production recovery and delayed decline was seen in the G2 as compared to all other groups. The immunohistochemistry of the pituitary gland reveals the decrease (P?0.01) in the cell and nucleus size as well as area of somatotrophs in G2 and G4 as compared to G1. The cell and nucleus size as well as area of lactotrophs decreased (P?0.01) in G2, G3 and G4 as compared to G1. The better and earlier post molt production in G2 highlights the potential role of protein supplementation in connection with the decreased lactotroph size and area in molted birds. PMID:23027344

Anwar, H; Rahman, Z U; Muhammad, F; Javed, I

2012-06-29

216

Larval Culture of Tachypleus gigas and Its Molting Behavior Under Laboratory Conditions  

Microsoft Academic Search

\\u000a Horseshoe crab populations along the northeast coast of India are under threat due to degradation of the breeding beaches.\\u000a To augment the trend, attempts were made to culture the larvae of Tachypleus gigas and study its growth rate by enhancing the molting pattern in the laboratory condition. Trilobites of T. gigas were cultured on a controlled diet of brine shrimp

J. K. Mishra

217

The Function and Evolution of the Halloween Genes: The Pathway to the Arthropod Molting Hormone  

Microsoft Academic Search

The Halloween genes of Drosophila melanogaster were first described in the 1980s using cytogenetic methodology. During the past several years the genes have been cloned,\\u000a expressed and the gene products have been characterized as cytochrome P450 enzymes (CYPs) and four have been functionalized\\u000a as mediating the final steps in the biosynthesis of the arthropod molting hormone, 20-hydroxyecdysone (20E). A fifth

Lawrence I. Gilbert; Kim F. Rewitz

218

Developmental expression of Manduca shade, the P450 mediating the final step in molting hormone synthesis  

Microsoft Academic Search

The ecdysone 20-monooxygenase (E20MO; 20-hydroxylase) is the enzyme that mediates the conversion of ecdysone (E) to the active insect molting hormone, 20-hydroxyecdysone (20E), which coordinates developmental progression. We report the identification and developmental expression of the Halloween gene shade (shd; CYP314A1) that encodes the E20MO in the tobacco hornworm, Manduca sexta. Manduca Shd (MsShd) mediates the conversion of E to

Kim F. Rewitz; Robert Rybczynski; James T. Warren; Lawrence I. Gilbert

2006-01-01

219

Female resistance and male preference in a stream-dwelling isopod: effects of female molt characteristics  

Microsoft Academic Search

In the stream-dwelling isopod, Lirceus fontinalis, mating contests between males and females occur prior to pair formation. We examined the relative contribution of male preference\\u000a and female resistance to contest outcomes. We first quantified male and female behavior during typical mating interactions\\u000a and examined the relationship between time until molt (TTM) and mating outcomes. We then examined the role of

Timothy C. Sparkes; Daniel P. Keogh; Kristin E. Haskins

2000-01-01

220

A review of gastric processing in decapod crustaceans.  

PubMed

This article reviews the mechanical processes associated with digestion in decapod crustaceans. The decapod crustacean gut is essentially an internal tube that is divided into three functional areas, the foregut, midgut, and hindgut. The foregut houses the gastric mill apparatus which functions in mastication (cutting and grinding) of the ingested food. The processed food passes into the pyloric region of the foregut which controls movement of digesta into the midgut region and hepatopancreas where intracellular digestion takes place. The movements of the foregut muscles and gastric mill are controlled via nerves from the stomatogastric ganglion. Contraction rates of the gastric mill and foregut muscles can be influenced by environmental factors such as salinity, temperature, and oxygen levels. Gut contraction rates depend on the magnitude of the environmental perturbation and the physiological ability of each species. The subsequent transit of the digesta from the foregut into the midgut and through the hindgut has been followed in a wide variety of crustaceans. Transit rates are commonly used as a measure of food processing rates and are keys in understanding strategies of adaptation to trophic conditions. Transit times vary from as little as 30 min in small copepods to over 150 h in larger lobsters. Transit times can be influenced by the size and the type of the meal, the size and activity level of an animal and changes in environmental temperature, salinity and oxygen tension. Ultimately, changes in transit times influence digestive efficiency (the amount of nutrients absorbed across the gut wall). Digestive efficiencies tend to be high for carnivorous crustaceans, but somewhat lower for those that consume plant material. A slowing of the transit rate allows more time for nutrient absorption but this may be confounded by changes in the environment, which may reduce the energy available for active transport processes. Given the large number of articles already published on the stomatogastric ganglion and its control mechanisms, this area will continue to be of interest to scientists. There is also a push towards studying animals in a more natural environment or even in the field and investigation of the energetic costs of the components of digestion under varying biotic and environmental conditions will undoubtedly be an area that expands in the future. PMID:23266655

McGaw, Iain J; Curtis, Daniel L

2012-12-25

221

Manganese bioconcentration in aquatic insects: Mn oxide coatings, molting loss, and Mn(II) thiol scavenging.  

PubMed

Streams below mountaintop removal-valley fill coal mining operations often have elevated Mn concentrations, but it remains unclear if Mn plays a role in biodiversity reduction. We examined various aspects of aqueous Mn interactions with aquatic insects exposed to environmentally relevant Mn concentrations, revealing complex behavior. First, Mn accumulation rates varied widely among 9 species. A significant percentage of total Mn accrued (mean 74%, range 24-95%) was associated with the cuticle, predominantly in the form of Mn-oxides, and to a lesser degree Mn(II). Mn II is also absorbed into tissues, possibly through calcium transporters. Increased ambient calcium concentrations decreased both adsorbed and absorbed Mn accumulation from solution. Though species showed similar Mn efflux rate constants (0.032-0.072 d(-1)), the primary mode of Mn loss was through molting. Both adsorbed and absorbed Mn is lost during the molt. Subcellular compartmentalization studies revealed an overwhelming tendency for internalized Mn to associate with the heat stable cytosolic protein fraction. After short dissolved Mn exposures, intracellular glutathione and cysteine levels were markedly reduced relative to controls. These findings suggest that Mn exposure results in transient physiological stress in aquatic insects which is likely relieved, in part, during the molting process. PMID:21049994

Dittman, Elizabeth K; Buchwalter, David B

2010-11-04

222

Identification of the molting hormone of the sweet potato (Bemisia tabaci) and greenhouse (Trialeurodes vaporariorum) whitefly.  

PubMed

In order to identify the whitefly molting hormone, whole body extracts of mature 4th instar and newly formed pharate adult Bemisia tabaci (Biotype B) and Trialeurodes vaporariorum were prepared and subjected to reverse phase high performance liquid chromatography (RPHPLC). Ecdysteroid content of fractions was determined by enzymeimmunoassay (EIA). The only detectable ecdysteroids that were present in significant amounts in whitefly extracts were ecdysone and 20-hydroxyecdysone. The concentrations of 20-hydroxyecdysone in B. tabaci and T. vaporariorum extracts, respectively, were 40 and 15 times greater than the concentrations of ecdysone. The identity of the two ecdysteroids was confirmed by normal phase high performance liquid chromatography (NPHPLC). When ecdysteroid content of RPHPLC fractions was assayed by radioimmunoassay (RIA), small amounts of polar ecdysteroids were also detected indicating that these ecdysteroids have a very low affinity for the antiserum used in the EIA. Ecdysteroid at 10.4 mM administered by feeding stimulated 2nd instar whitefly nymphs to molt. Based on our results, it appears that 20-hydroxyecdysone is the whitefly molting hormone. PMID:15686645

Gelman, Dale B; Blackburn, Michael B; Hu, Jing S

2005-01-01

223

An introductory survey of ecology and sensory receptors of tropical eastern pacific crustaceans  

Microsoft Academic Search

A comparative survey of sensory organs (mainly visual) of 35 species of crustaceans (Mysidacea, Stomatopoda and Decapoda) was initiated in the SE Gulf of California, Mexico, an enclosed sea which has been well studied for its physical conditions and the taxonomy of crustacean species. The purpose of this survey was to study how the perceptive capacities are conditioned by the

Helga Schiff; Michel E. Hendrickx

1997-01-01

224

Crustaceans associated with Cnidaria, Bivalvia, Echinoidea and Pisces at São Tomé and Príncipe islands  

Microsoft Academic Search

Symbiotic crustaceans were searched for at sea anemones (Actiniaria), encrusting anemones (Zoantharia), horny coral (Gorgonaria), black coral (Antipatharia), bivalves (Bivalvia), and sea urchins (Echinoidea) at São Tomé and Príncipe Islands (Gulf of Guinea, eastern central Atlantic). Sixteen species of crustaceans were found in association with these invertebrate hosts; eleven of them were new records for the area and two species,

PETER WIRTZ

225

Insecticidal Juvenile Hormone Analogs Stimulate the Production of Male Offspring in the Crustacean Daphnia magna  

Microsoft Academic Search

Juvenile hormone analogs (JHAs) represent a class of insecticides that were designed specifically to disrupt endocrine-regulated processes relatively unique to insects. Recently we demonstrated that the crustacean juvenoid hormone methyl farnesoate programs oocytes of the crustacean Daphnia magna to develop into males. We hypothesized that insecticidal JHAs might mimic the action of methyl far- nesoate, producing altered sex ratios of

Allen W. Olmstead; Gerald A. LeBlanc

2003-01-01

226

Activity of crustacean myotropic neuropeptides on the oviduct and hindgut of the crayfish Astacus leptodactylus  

Technology Transfer Automated Retrieval System (TEKTRAN)

In crustaceans, a large number of peptides have been identified because of their effect on visceral muscles. Predominantly the heart and the hindgut have been used to purify myotropic peptides from crustaceans. Lately, a number of myotropins were purified from the central nervous system of crustace...

227

Do Decapod Crustaceans Have Nociceptors for Extreme pH?  

PubMed Central

Background Nociception is the physiological detection of noxious stimuli. Because of its obvious importance, nociception is expected to be widespread across animal taxa and to trigger robust behaviours reliably. Nociception in invertebrates, such as crustaceans, is poorly studied. Methodology/Principal Findings Three decapod crustacean species were tested for nociceptive behaviour: Louisiana red swamp crayfish (Procambarus clarkii), white shrimp (Litopenaeus setiferus), and grass shrimp (Palaemonetes sp.). Applying sodium hydroxide, hydrochloric acid, or benzocaine to the antennae caused no change in behaviour in the three species compared to controls. Animals did not groom the stimulated antenna, and there was no difference in movement of treated individuals and controls. Extracellular recordings of antennal nerves in P. clarkii revealed continual spontaneous activity, but no neurons that were reliably excited by the application of concentrated sodium hydroxide or hydrochloric acid. Conclusions/Significance Previously reported responses to extreme pH are either not consistently evoked across species or were mischaracterized as nociception. There was no behavioural or physiological evidence that the antennae contained specialized nociceptors that responded to pH.

Puri, Sakshi; Faulkes, Zen

2010-01-01

228

Discovery and functional study of a novel crustacean tachykinin neuropeptide.  

PubMed

Tachykinin-related peptide (TRP) refers to a large and structurally diverse family of neuropeptides found in vertebrate and invertebrate nervous systems. These peptides have various important physiological functions, from regulating stress in mammals to exciting the pyloric (food filtering) rhythm in the stomatogastric nervous system (STNS) of decapod crustaceans. Here, a novel TRP, which we named CalsTRP (Callinectes sapidus TRP), YPSGFLGMRamide (m/z 1026.52), was identified and de novo sequenced using a multifaceted mass spectrometry-based platform in both the central nervous system (CNS) and STNS of C. sapidus. We also found, using isotopic formaldehyde labeling, that CalsTRP in the C. sapidus brain and commissural ganglion (CoG) was up-regulated after food-intake, suggesting that TRPs in the CNS and STNS are involved in regulating feeding in Callinectes. Using imaging mass spectrometry, we determined that the previously identified CabTRP Ia (APSGFLGMRamide) and CalsTRP were co-localized in the C. sapidus brain. Lastly, our electrophysiological studies show that bath-applied CalsTRP and CabTRP Ia each activates the pyloric and gastric mill rhythms in C. sapidus, as shown previously for pyloric rhythm activation by CabTRP Ia in the crab Cancer borealis. In summary, the newly identified CalsTRP joins CabTRP Ia as a TRP family member in the decapod crustacean nervous system, whose actions include regulating feeding behavior. PMID:22247794

Hui, Limei; Zhang, Yuzhuo; Wang, Junhua; Cook, Aaron; Ye, Hui; Nusbaum, Michael P; Li, Lingjun

2011-12-21

229

Decoupling elongation and segmentation: notch involvement in anostracan crustacean segmentation.  

PubMed

Repeated body segments are a key feature of arthropods. The formation of body segments occurs via distinct developmental pathways within different arthropod clades. Although some species form their segments simultaneously without any accompanying measurable growth, most arthropods add segments sequentially from the posterior of the growing embryo or larva. The use of Notch signaling is increasingly emerging as a common feature of sequential segmentation throughout the Bilateria, as inferred from both the expression of proteins required for Notch signaling and the genetic or pharmacological disruption of Notch signaling. In this study, we demonstrate that blocking Notch signaling by blocking ?-secretase activity causes a specific, repeatable effect on segmentation in two different anostracan crustaceans, Artemia franciscana and Thamnocephalus platyurus. We observe that segmentation posterior to the third or fourth trunk segment is arrested. Despite this marked effect on segment addition, other aspects of segmentation are unaffected. In the segments that develop, segment size and boundaries between segments appear normal, engrailed stripes are normal in size and alignment, and overall growth is unaffected. By demonstrating Notch involvement in crustacean segmentation, our findings expand the evidence that Notch plays a crucial role in sequential segmentation in arthropods. At the same time, our observations contribute to an emerging picture that loss-of-function Notch phenotypes differ significantly between arthropods suggesting variability in the role of Notch in the regulation of sequential segmentation. This variability in the function of Notch in arthropod segmentation confounds inferences of homology with vertebrates and lophotrochozoans. PMID:22765208

Williams, Terri; Blachuta, Beata; Hegna, Thomas A; Nagy, Lisa M

2012-07-01

230

Structural marsh management effects on coastal fishes and crustaceans  

NASA Astrophysics Data System (ADS)

Structural marsh management, using levees and water-control structures, is used in the coastal zone for many objectives, for example, to reduce marsh loss, to enhance waterfowl habitat, to revegetate open-water areas, and to reduce saltwater intrusion. The literature was evaluated to categorize structural marsh management and to determine some of its effects on fishes and crustaceans. Structural marsh management had positive effects on standing stock of most resident organisms and negative effects on marine-transient organisms. Emigration was negatively affected for both resident and marine-transient organisms. Techniques such as opening structures at critical migration times, designing structures that offer the greatest management flexibility, and using structures to create a flow-through system could reduce these impacts. More effort should be put into monitoring managed areas to determine if the objectives are being met and to evaluate the effects on fishes and crustaceans. Although frequent manipulation could reduce these impacts, the costs and problems incurred may outweigh the anticipated benefits.

Rogers, Donna R.; Rogers, Barton D.; Herke, William H.

1994-05-01

231

Higher-level crustacean phylogeny: consensus and conflicting hypotheses.  

PubMed

This paper presents an overview of current hypotheses of higher-level crustacean phylogeny in order to assist and help focus further research. It concentrates on hypotheses proposed or debated in the recent literature based on morphological, molecular and combined evidence phylogenetic analyses. It can be concluded that crustacean phylogeny remains essentially unresolved. Conflict is rife, irrespective of whether one compares different morphological studies, molecular studies, or both. Using the number of recently proposed alternative sister group hypotheses for each of the major tetraconatan taxa as a rough estimate of phylogenetic uncertainty, it can be concluded that the phylogenetic position of Malacostraca remains the most problematic, closely followed by Branchiopoda, Cephalocarida, Remipedia, Ostracoda, Branchiura, Copepoda and Hexapoda. Future progress will depend upon a broader taxon sampling in molecular analyses, and the further exploration of new molecular phylogenetic markers. However, the need for continued revision and expansion of morphological datasets remains undiminished given the conspicuous lack of agreement between molecules and morphology for positioning several taxa. In view of the unparalleled morphological diversity of Crustacea, and the likely nesting of Hexapoda somewhere within Crustacea, working out a detailed phylogeny of Tetraconata is a crucial step towards understanding arthropod body plan evolution. PMID:19944189

Jenner, Ronald A

2009-11-28

232

Multiple defender effects: synergistic coral defense by mutualist crustaceans.  

PubMed

The majority of our understanding of mutualisms comes from studies of pairwise interactions. However, many hosts support mutualist guilds, and interactions among mutualists make the prediction of aggregate effects difficult. Here, we apply a factorial experiment to interactions of 'guard' crustaceans that defend their coral host from seastar predators. Predation was reduced by the presence of mutualists (15% reduction in predation frequency and 45% in volume of coral consumed). The frequency of attacks with both mutualists was lower than with a single species, but it did not differ significantly from the expected frequency of independent effects. In contrast, the combined defensive efficacy of both mutualist species reduced the volume of coral tissue lost by 73%, significantly more than the 38% reduction expected from independent defensive efforts, suggesting the existence of a cooperative synergy in defensive behaviors of 'guard' crustaceans. These emergent 'multiple defender effects' are statistically and ecologically analogous to the emergent concept of 'multiple predator effects' known from the predation literature. PMID:22374368

McKeon, C Seabird; Stier, Adrian C; McIlroy, Shelby E; Bolker, Benjamin M

2012-02-29

233

Ultraviolet polarisation sensitivity in the stomatopod crustacean Odontodactylus scyllarus.  

PubMed

The ommatidia of crustacean eyes typically contain two classes of photoreceptors with orthogonally oriented microvilli. These receptors provide the basis for two-channel polarisation vision in the blue-green spectrum. The retinae of gonodactyloid stomatopod crustaceans possess a great variety of structural specialisations for elaborate polarisation vision. One type of specialisation is found in the small, distally placed R8 cells within the two most ventral rows of the mid-band. These ultraviolet-sensitive photoreceptors produce parallel microvilli, a feature suggestive for polarisation-sensitive photoreceptors. Here, we show by means of intracellular recordings combined with dye-injections that in the gonodactyloid species Odontodactylus scyllarus, the R8 cells of mid-band rows 5 and 6 are sensitive to linear polarised ultraviolet light. We show that mid-band row 5 R8 cells respond maximally to light with an e-vector oriented parallel to the mid-band, whereas mid-band row 6 R8 cells respond maximally to light with an e-vector oriented perpendicular to the mid-band. This orthogonal arrangement of ultraviolet-sensitive receptor cells could support ultraviolet polarisation vision. R8 cells of rows 5 and 6 are known to act as quarter-wave retarders around 500 nm and thus are the first photoreceptor type described with a potential dual role in polarisation vision. PMID:19924415

Kleinlogel, Sonja; Marshall, N Justin

2009-11-19

234

The effects of ethidium bromide induced loss of mitochondrial DNA on mitochondrial phenotype and ultrastructure in a human leukemia T-cell line (MOLT4 cells)  

Microsoft Academic Search

Mitochondrial DNA-deficient (?0) cells were generated following a 26-day incubation of MOLT-4 lymphoblastoid T cells in ethidium bromide (3,8-diamino-5-ethyl-6-phenylphenanthridinium bromide). The absence of mitochondrial DNA (mtDNA) in the resultant MOLT-4 ?0 cells was confirmed by Southern analysis and quantitative polymerase chain reaction (PCR). MOLT-4 ?0 cells proliferated more slowly than parental cells (wild type) and produced significantly more lactate (approximately

Ray Armand; Jacqueline Y Channon; Jennifer Kintner; Kristina A White; Kristin A Miselis; Raymond P Perez; Lionel D Lewis

2004-01-01

235

The complete mitochondrial genome of the stomatopod crustacean Squilla mantis  

PubMed Central

Background Animal mitochondrial genomes are physically separate from the much larger nuclear genomes and have proven useful both for phylogenetic studies and for understanding genome evolution. Within the phylum Arthropoda the subphylum Crustacea includes over 50,000 named species with immense variation in body plans and habitats, yet only 23 complete mitochondrial genomes are available from this subphylum. Results I describe here the complete mitochondrial genome of the crustacean Squilla mantis (Crustacea: Malacostraca: Stomatopoda). This 15994-nucleotide genome, the first described from a hoplocarid, contains the standard complement of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a non-coding AT-rich region that is found in most other metazoans. The gene order is identical to that considered ancestral for hexapods and crustaceans. The 70% AT base composition is within the range described for other arthropods. A single unusual feature of the genome is a 230 nucleotide non-coding region between a serine transfer RNA and the nad1 gene, which has no apparent function. I also compare gene order, nucleotide composition, and codon usage of the S. mantis genome and eight other malacostracan crustaceans. A translocation of the histidine transfer RNA gene is shared by three taxa in the order Decapoda, infraorder Brachyura; Callinectes sapidus, Portunus trituberculatus and Pseudocarcinus gigas. This translocation may be diagnostic for the Brachyura. For all nine taxa nucleotide composition is biased towards AT-richness, as expected for arthropods, and is within the range reported for other arthropods. Codon usage is biased, and much of this bias is probably due to the skew in nucleotide composition towards AT-richness. Conclusion The mitochondrial genome of Squilla mantis contains one unusual feature, a 230 base pair non-coding region has so far not been described in any other malacostracan. Comparisons with other Malacostraca show that all nine genomes, like most other mitochondrial genomes, share a bias toward AT-richness and a related bias in codon usage. The nine malacostracans included in this analysis are not representative of the diversity of the class Malacostraca, and additional malacostracan sequences would surely reveal other unusual genomic features that could be useful in understanding mitochondrial evolution in this taxon.

Cook, Charles E

2005-01-01

236

Catalogue of epidermal genes: Genes expressed in the epidermis during larval molt of the silkworm Bombyx mori  

PubMed Central

Background The insect cuticle is composed of various proteins and formed during the molt under hormonal regulation, although its precise composition and formation mechanism are largely unknown. The exhaustive catalogue of genes expressed in epidermis at the molt constitutes a massive amount of information from which to draw a complete picture of the molt and cuticle formation in insects. Therefore, we have catalogued a library of full-length cDNAs (designated epM) from epidermal cells during the last larval molt of Bombyx mori. Results Of the 10,368 sequences in the library, we isolated 6,653 usable expressed sequence tags (ESTs), which were categorized into 1,451 nonredundant gene clusters. Seventy-one clusters were considered to be isoforms or premature forms of other clusters. Therefore, we have identified 1,380 putative genes. Of the 6,653 expressed sequences, 48% were derived from 92 cuticular protein genes (RR-1, 24; RR-2, 17; glycine-rich, 29; other classes, 22). A comparison of epM with another epidermal EST data set, epV3 (feeding stage: fifth instar, day 3), showed marked differences in cuticular protein gene. Various types of cuticular proteins are expressed in epM but virtually only RR-1 proteins were expressed in epV3. Cuticular protein genes expressed specifically in epidermis, with several types of expression patterns during the molt, suggest different types of responses to the ecdysteroid pulse. Compared with other Bombyx EST libraries, 13 genes were preferentially included in epM data set. We isolated 290 genes for proteins other than cuticular proteins, whose amino acid sequences retain putative signal peptides, suggesting that they play some role in cuticle formation or in other molting events. Several gene groups were also included in this data set: hormone metabolism, P450, modifier of cuticular protein structure, small-ligand-binding protein, transcription factor, and pigmentation genes. Conclusion We have identified 1,380 genes in epM data set and 13 preferentially expressed genes in epidermis at the molt. The comparison of the epM and other EST libraries clarified the totally different gene expression patterns in epidermis between the molting and feeding stages and many novel tissue- and stage-specifically expressed epidermal genes. These data should further our understanding of cuticle formation and the insect molt.

Okamoto, Shun; Futahashi, Ryo; Kojima, Tetsuya; Mita, Kazuei; Fujiwara, Haruhiko

2008-01-01

237

Filling the gap between identified neuroblasts and neurons in crustaceans adds new support for Tetraconata  

PubMed Central

The complex spatio-temporal patterns of development and anatomy of nervous systems play a key role in our understanding of arthropod evolution. However, the degree of resolution of neural processes is not always detailed enough to claim homology between arthropod groups. One example is neural precursors and their progeny in crustaceans and insects. Pioneer neurons of crustaceans and insects show some similarities that indicate homology. In contrast, the differentiation of insect and crustacean neuroblasts (NBs) shows profound differences and their homology is controversial. For Drosophila and grasshoppers, the complete lineage of several NBs up to formation of pioneer neurons is known. Apart from data on median NBs no comparable results exist for Crustacea. Accordingly, it is not clear where the crustacean pioneer neurons come from and whether there are NBs lateral to the midline homologous to those of insects. To fill this gap, individual NBs in the ventral neuroectoderm of the crustacean Orchestia cavimana were labelled in vivo with a fluorescent dye. A partial neuroblast map was established and for the first time lineages from individual NBs to identified pioneer neurons were established in a crustacean. Our data strongly suggest homology of NBs and their lineages, providing further evidence for a close insect–crustacean relationship.

Ungerer, Petra; Scholtz, Gerhard

2007-01-01

238

Digestion in relation to feeding strategies exhibited by crustacean larvae.  

PubMed

Decapod crustaceans have adopted a full range of reproductive strategies from the release of large numbers of small eggs (Penaeoidea) to the release of relatively low numbers of large advanced larvae (Nephropidae). As larval size determines trophic position in planktonic food webs, all food sources from phyto- to zooplankton are exploited, with many species changing trophic level during ontogenetic development. Comparative studies on digestive enzymes, levels of activity and changes during ontogeny, together with measurements of gastroevacuation rates and food energy values appear to reveal a general pattern. While herbivorous decapod larvae adapt to low food energy values with high enzyme activity levels, rapid food turnover and low assimilation efficiency, carnivorous larvae exhibit low levels of enzyme activity but compensate by extending retention time of high-energy food to maximise assimilation efficiency. New studies on digestive enzyme levels during development in the penaeid Litopenaeus vannamei, the caridean Lysmata debelius and the cirriped Elminius modestus, appear to agree with previous observations. PMID:11246049

Le Vay, L; Jones, D A; Puello-Cruz, A C; Sangha, R S; Ngamphongsai, C

2001-03-01

239

Photoinduced toxicity of fluoranthene to seven marine benthic crustaceans.  

PubMed

Seven marine benthic crustaceans were exposed in 4 d water-only toxicity tests to five concentrations of fluoranthene. After exposures, mortality (LC50) and the ability to bury in clean sediment (EC50) were determined. Survivors were then exposed to UV radiation for 1 h. The differences between LC50s and EC50s before and after UV exposure were used to assess photoinduced toxicity. UV exposure enhanced fluoranthene toxicity by as much as tenfold in five of the seven species tested (Rhepoxynius abronius, Eohaustorius estuarius, Leptocheirus plumulosus, Grandidierella japonica, and Corophium insidiosum). Species having the greatest potential for natural exposure to sunlight (Excirolana vancouverensis and Emerita analoga) were the least sensitive to photoinduced fluoranthene toxicity. Although photoinduced toxicity needs to be considered in environmental risk assessments, testing should be done, using ecologically relevant species and exposures. PMID:9175504

Boese, B L; Lamberson, J O; Swartz, R C; Ozretich, R J

1997-05-01

240

THE FINE STRUCTURE OF FAST AND SLOW CRUSTACEAN MUSCLES  

PubMed Central

Known phasic and tonic muscle fibers of the crab Cancer magister were studied by electron microscopy. Phasic fibers have sarcomeres about 4.5 µ long, small polygonal myofibrils, and a well-developed sarcoplasmic reticulum. The thick myofilaments, disposed in hexagonal array, are each surrounded by six thin filaments. The tonic fibers have a sarcomere length of about 12 µ, larger myofibrils, a poorly developed sarcoplasmic reticulum, and a disorderly array of myofilaments. Each thick myofilament is surrounded by 10–12 thin filaments. The same morphological type of slow muscle has been found in the crustaceans, Macrocyclops albidus, Cypridopsis vidua, and Balanus cariosus, in each case in an anatomical location consistent with tonic action. A search of the literature indicates that this type of muscle is found in all classes of arthropods and is confined to visceral and postural muscles or specializations of these.

Fahrenbach, Wolf H.

1967-01-01

241

Recrudescence Mechanisms and Gene Expression Profile of the Reproductive Tracts from Chickens during the Molting Period  

PubMed Central

The reproductive system of chickens undergoes dynamic morphological and functional tissue remodeling during the molting period. The present study identified global gene expression profiles following oviductal tissue regression and regeneration in laying hens in which molting was induced by feeding high levels of zinc in the diet. During the molting and recrudescence processes, progressive morphological and physiological changes included regression and re-growth of reproductive organs and fluctuations in concentrations of testosterone, progesterone, estradiol and corticosterone in blood. The cDNA microarray analysis of oviductal tissues revealed the biological significance of gene expression-based modulation in oviductal tissue during its remodeling. Based on the gene expression profiles, expression patterns of selected genes such as, TF, ANGPTL3, p20K, PTN, AvBD11 and SERPINB3 exhibited similar patterns in expression with gradual decreases during regression of the oviduct and sequential increases during resurrection of the functional oviduct. Also, miR-1689* inhibited expression of Sp1, while miR-17-3p, miR-22* and miR-1764 inhibited expression of STAT1. Similarly, chicken miR-1562 and miR-138 reduced the expression of ANGPTL3 and p20K, respectively. These results suggest that these differentially regulated genes are closely correlated with the molecular mechanism(s) for development and tissue remodeling of the avian female reproductive tract, and that miRNA-mediated regulation of key genes likely contributes to remodeling of the avian reproductive tract by controlling expression of those genes post-transcriptionally. The discovered global gene profiles provide new molecular candidates responsible for regulating morphological and functional recrudescence of the avian reproductive tract, and provide novel insights into understanding the remodeling process at the genomic and epigenomic levels.

Ahn, Suzie E.; Lim, Chul-Hong; Lee, Jin-Young; Bae, Seung-Min; Kim, Jinyoung; Bazer, Fuller W.; Song, Gwonhwa

2013-01-01

242

Chymotrypsin-like peptidases from Tribolium castaneum: a role in molting revealed by RNA interference.  

PubMed

Chymotrypsin-like peptidases (CTLPs) of insects are primarily secreted into the gut lumen where they act as digestive enzymes. We studied the gene family encoding CTLPs in the genome of the red flour beetle, Tribolium castaneum. Using an extended search pattern, we identified 14 TcCTLP genes that encode peptidases with S1 specificity pocket residues typically found in chymotrypsin-like enzymes. We further analyzed the expression patterns of seven TcCTLP genes at various developmental stages. While some TcCTLP genes were exclusively expressed in feeding larval and adult stages (TcCTLP-5A/B, TcCTLP-6A), others were also detected in non-feeding embryonic (TcCTLP-5C, TcCTLP-6D) and pupal stages (TcCTLP-5C, TcCTLP-6C/D/E). TcCTLP genes were expressed predominantly in the midgut, where they presumably function in digestion. However, TcCTLP-6C and TcCTLP-5C also showed considerable expression in the carcass. The latter two genes might therefore encode peptidases that act as molting fluid enzymes. To test this hypothesis, we performed western blots using protein extracts from larval exuviae. The extracts reacted with antibodies to TcCTLP-5C and TcCTLP-6E suggesting that the corresponding peptidases are secreted into the molting fluid. Finally, we performed systemic RNAi experiments. While injections of five TcCTLP-dsRNAs into penultimate larvae did not affect growth or development, injection of dsRNA for TcCTLP-5C and TcCTLP-6C resulted in severe molting defects. PMID:19897036

Broehan, Gunnar; Arakane, Yasuyuki; Beeman, Richard W; Kramer, Karl J; Muthukrishnan, Subbaratnam; Merzendorfer, Hans

2009-11-06

243

Proteolytic cleavage of phospholipase C-gamma1 during apoptosis in Molt-4 cells.  

PubMed

Apoptosis is a cell suicide mechanism that requires the activation of cellular death proteases for its induction. We examined whether the progress of apoptosis involves cleavage of phospholipase C-gamma1 (PLC-gamma1), which plays a pivotal role in mitogenic signaling pathway. Pretreatment of T leukemic Molt-4 cells with PLC inhibitors such as U-73122 or ET-18-OCH(3) potentiated etoposide-induced apoptosis in these cells. PLC-gamma1 was fragmented when Molt-4 cells were treated with several apoptotic stimuli such as etoposide, ceramides, and tumor necrosis factor alpha. Cleavage of PLC-gamma1 was blocked by overexpression of Bcl-2 and by specific inhibitors of caspases such as Z-DEVD-CH(2)F and YVAD-cmk. Purified caspase-3 and caspase-7, group II caspases, cleaved PLC-gamma1 in vitro and generated a cleavage product of the same size as that observed in vivo, suggesting that PLC-gamma1 is cleaved by group II caspases in vivo. From point mutagenesis studies, Ala-Glu-Pro-Asp(770) was identified to be a cleavage site within PLC-gamma1. Epidermal growth factor receptor (EGFR) -induced tyrosine phosphorylation of PLC-gamma1 resulted in resistance to cleavage by caspase-3 in vitro. Furthermore, cleaved PLC-gamma1 could not be tyrosine-phosphorylated by EGFR in vitro. In addition, tyrosine-phosphorylated PLC-gamma1 was not significantly cleaved during etoposide-induced apoptosis in Molt-4 cells. This suggests that the growth factor-induced tyrosine phosphorylation may suppress apoptosis-induced fragmentation of PLC-gamma1. We provide evidence for the biochemical relationship between PLC-gamma1-mediated signal pathway and apoptotic signal pathway, indicating that the defect of PLC-gamma1-mediated signaling pathway can facilitate an apoptotic progression. PMID:10834929

Bae, S S; Perry, D K; Oh, Y S; Choi, J H; Galadari, S H; Ghayur, T; Ryu, S H; Hannun, Y A; Suh, P G

2000-06-01

244

Arthropod phylogeny revisited, with a focus on crustacean relationships.  

PubMed

Higher-level arthropod phylogenetics is an intensely active field of research, not least as a result of the hegemony of molecular data. However, not all areas of arthropod phylogenetics have so far received equal attention. The application of molecular data to infer a comprehensive phylogeny of Crustacea is still in its infancy, and several emerging results are conspicuously at odds with morphology-based studies. In this study, we present a series of molecular phylogenetic analyses of 88 arthropods, including 57 crustaceans, representing all the major lineages, with Onychophora and Tardigrada as outgroups. Our analyses are based on published and new sequences for two mitochondrial markers, 16S rDNA and cytochrome c oxidase subunit I (COI), and the nuclear ribosomal gene 18S rDNA. We designed our phylogenetic analyses to assess the effects of different strategies of sequence alignment, alignment masking, nucleotide coding, and model settings. Our comparisons show that alignment optimization of ribosomal markers based on secondary structure information can have a radical impact on phylogenetic reconstruction. Trees based on optimized alignments recover monophyletic Arthropoda (excluding Onychophora), Pancrustacea, Malacostraca, Insecta, Myriapoda and Chelicerata, while Maxillopoda and Hexapoda emerge as paraphyletic groups. Our results are unable to resolve the highest-level relationships within Arthropoda, and none of our trees supports the monophyly of Myriochelata or Mandibulata. We discuss our results in the context of both the methodological variations between different analyses, and of recently proposed phylogenetic hypotheses. This article offers a preliminary attempt to incorporate the large diversity of crustaceans into a single molecular phylogenetic analysis, assessing the robustness of phylogenetic relationships under varying analysis parameters. It throws into sharp relief the relative strengths and shortcomings of the combined molecular data for assessing this challenging phylogenetic problem, and thereby provides useful pointers for future studies. PMID:19854296

Koenemann, Stefan; Jenner, Ronald A; Hoenemann, Mario; Stemme, Torben; von Reumont, Björn M

2009-11-05

245

Decapod crustaceans in fresh waters of southeastern Bahia, Brazil.  

PubMed

A total of 117 species of freshwater decapod crustaceans are known from Brazil. Knowledge regarding the fauna of Decapoda from inland waters in the state of Bahia, northeast Brazil, is incipient. In spite of its wide territory and rich hydrographic net, only 13 species of limnetic decapods have been reported from that state. The objective of this contribution was to survey decapod crustaceans of some hydrographic basins in southeastern Bahia. The material described herein was obtained in samplings conducted between 1997 and 2005. Voucher specimens were deposited in the carcinological collections of the Museu de Zoologia, Universidade Estadual de Santa Cruz, Ilhéus, Brazil, and Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, Brazil. A total of 13 species was collected. The carideans were represented by the atyids Atya scabra (Leach, 1815) and Potimirim potimirim (Müller, 1881) and the palaemonids Macrobrachium acanthurus (Wiegmann, 1836), M. amazonicum (Heller, 1862), M. carcinus (Linnaeus, 1758), M. heterochirus (Wiegmann, 1836), M. jelskii (Miers, 1877), M. olfersi (Wiegmann, 1836), and Palaemon (Palaemon) pandaliformis (Stimpson, 1871). The brachyurans were represented by the portunids Callinectes bocourti A. Milne-Edwards, 1879 and C. sapidus Rathbun, 1895, the trichodactylid Trichodactylus fluviatilis Latreille, 1828 and the panopeid Panopeus rugosus A. Milne-Edwards, 1881. Macrobrachium heterochirus represents a new record from Bahia, and M. amazonicum is reported for the first time in southeast Bahia. The occurrence of two extreme different forms of T. fluviatilis was observed. Form A is characterized by the frontal margin of carapace bordered by conspicuous granules, the anterolateral margin provided with developed teeth plus granules, and the posterolateral margin provided with granulation similar to that found on the front. In form B the frontal margin is smooth or has an inconspicuous granulation; the anterolateral margin is usually provided with 1-3 notches, and teeth (1-2), if present, are small; and the posterolateral margin is smooth or slightly granulated. PMID:19419041

de Almeida, Alexandre Oliveira; Coelho, Petrônio Alves; Luz, Joaldo Rocha; dos Santos, José Tiago Almeida; Ferraz, Neyva Ribeiro

2008-09-01

246

Effects of aluminum and acidity of the drift, mortality, and molting of stream insects. Research report  

SciTech Connect

Responses of nine stream insects to short-term increases of acidity and aluminum concentrations in artificial streams were studied. For the mayflies studied (Stenonema modestum Ephemerella subvaria and E. catawba) drifting behavior increased when aluminum concentrations were elevated above 1 ppm and mortality was increased at pH 5. Three of the four caddisflies studied (Hydropsyche ssp., Macrostemum zebratum, and Chimarra obscurra) were affected by increased salinities in high aluminum treatments, but were not adversely affected by short-term increases in acidity or aluminum concentrations. Molting success of the insects was reduced by increased acidity.

Cook, W.; Haney, J.

1986-01-01

247

Unique pattern of molt leads to low intraindividual variation in feather mercury concentrations in penguins.  

PubMed

The authors hypothesized that the catastrophic annual molt of penguins (Sphenisciformes) would lead to reduced intraindividual variation of mercury concentrations in body feathers. While mean mercury concentrations varied significantly among 8 penguin species, intraindividual variability did not differ among species and was 3 times lower than values observed in other seabirds. The findings of the present study suggest that a single body feather collected at random per individual can be adequate to estimate mercury exposure at the population level in penguins. Environ Toxicol Chem 2013;32:2331-2334. © 2013 SETAC. PMID:23761066

Brasso, Rebecka L; Drummond, Bridgette E; Borrett, Stuart R; Chiaradia, André; Polito, Michael J; Rey, Andrea Raya

2013-08-14

248

Molecular cloning and sequencing of a cDNA encoding partial putative molt-inhibiting hormone from Penaeus chinensis  

NASA Astrophysics Data System (ADS)

Total RNA was extracted from eyestalks of shrimp Penaeus chinensis. Eyestalk cDNA was obtained from total RNA by reverse transcription. Reverse transcriptase-polymerase chain reaction (RT-PCR) was initiated using eyestalk cDNA and degenerate primers designed from the amino acid sequence of molt-inhibiting hormone from shrimp Penaeus japonicus. A specific cDNA was obtained and cloned into a T vector for sequencing. The cDNA consisted of 201 base pairs and encoding for a peptide of 67 amino acid residues. The peptide of P. chinensis had the highest identity with molt-inhibiting hormones of P. japonicus. The cDNA could be a partial gene of molt-inhibiting hormones from P. chinensis. This paper reports for the first time cDNA encoding for neuropeptide of P. chinensis.

Wang, Zai-Zhao; Xiang, Jian-Hai

2002-09-01

249

Size Dimorphism, Molt Status, and Body Mass Variation of Prairie Falcons Nesting in the Snake River Birds of Prey National Conservation Area  

Microsoft Academic Search

Birds face challenges in how they allocate energy during the reproductive season. Most temperate zone species do not breed and molt at the same time, presumably because of the high energy demands of these two activities (Espie et al. 1996 and citations therein). However, representatives of at least four raptor genera are known to molt during the nesting season (Schmutz

Karen Steenhof; James O. McKinley; Cheryl R. Dykstra

2006-01-01

250

Morphometric analysis of the calcium-transporting sternal epithelial cells of the terrestrial isopods Ligia oceanica, Ligidium hypnorum, and Porcellio scaber during molt  

Microsoft Academic Search

Isopods shed first the posterior and then the anterior half of the body. Before molt, most terrestrial species resorb CaCO3 from the posterior mineralized cuticle. The mineral is stored in anterior sternal deposits, which are used to calcify the new posterior cuticle after molt. For Porcellio scaber it is known that the anterior sternal epithelium has specific structural differentiations for

Juliane Glötzner; Andreas Ziegler

2000-01-01

251

POLYCLONAL ANTISERA AGAINST ESTUARINE CRUSTACEAN VITELLINS: A MOLECULAR APPROACH TO REPRODUCTIVE ENDOCRINOLOGY AND TOXICOLOGY  

EPA Science Inventory

To fully elucidate the action of crustacean hormones, or their agonists, on reproduction and vitellogenesis it has become increasingly important to develop sensitive assays that indicate a stimulatory or inhibitory effect on easily measured endpoints. Because of the relative abun...

252

POLYCLONAL ANTISERA AGAINST ESTUARINE CRUSTACEAN VITELLINS: A MOLECULAR APPROACH TO REPRODUCTIVE ENDOCRINOLOGY AND TOXICOLOGY.  

EPA Science Inventory

To fully elucidate the action of crustacean hormones, or their agonists, on vitellogenesis and reproduction, it has become increasingly important to develop sensitive assays that indicate a stimulatory or inhibitory effect on easily measured endpoints. Because of the relative ab...

253

A new inosine disaccharide from the crustacean Ligia exotica: isolation and structure elucidation by total synthesis.  

PubMed

A novel nucleoside has been isolated from the crustacean Ligia exotica, and the structure was elucidated as 3'-O-(alpha-D-glucosyl)inosine, 1, by analysis of spectroscopic data and by total synthesis. PMID:11000016

Kim, S H; Yoo, S M; Park, I S; Kim, Y H

2000-09-01

254

Molecular cloning of tropomyosins identified as allergens in six species of crustaceans.  

PubMed

Although tropomyosin is known to be a major allergen of crustaceans, its structural information is limited to only five species. In this study, tropomyosin was confirmed to be a major allergen in six species of crustaceans (black tiger prawn, kuruma prawn, pink shrimp, king crab, snow crab, and horsehair crab) by immunoblotting. Then, the amino acid sequences of tropomyosins from these crustaceans were elucidated by a cDNA cloning technique. Sequence data for crustacean tropomyosins including the obtained results reveal that fast tropomyosins are contained in shrimps (or prawns) and lobsters, slow tropomyosins in crabs, and both tropomyosins in crayfishes and hermit crabs. Although fast and slow tropomyosins share a high sequence identity (about 90%) with each other, significant differences are observed in specific regions between both tropomyosins. PMID:17263503

Motoyama, Kanna; Suma, Yota; Ishizaki, Shoichiro; Nagashima, Yuji; Shiomi, Kazuo

2007-02-01

255

Amino Acids and TOR Signaling Promote Prothoracic Gland Growth and the Initiation of Larval Molts in the Tobacco Hornworm Manduca sexta  

PubMed Central

Molting in arthropods is orchestrated by a series of endocrine changes that occur towards the end of an instar. However, little is understood about the mechanisms that trigger these endocrine changes. Here, nutritional inputs were manipulated to investigate the minimal nutritional inputs required for a Manduca sexta larva to initiate a molt. Amino acids were found to be necessary for a larva to molt, indicating the involvement of an amino acid sensitive pathway. Feeding rapamycin, an inhibitor of the target of rapamycin (TOR) signaling, delayed the onset of a molt and resulted in abnormally larger larvae. Rapamycin also suppressed the growth of the prothoracic glands relative to the whole body growth, and this was accompanied by suppression of ecdysone production and secretion. Higher doses of rapamycin also slowed the growth rate, indicating that TOR signaling also plays a role in systemic growth. TOR signaling therefore couples the nutritional status of the larva to the endocrine system to regulate the timing of a molt.

Kemirembe, Karen; Liebmann, Kate; Bootes, Abigail; Smith, Wendy A.; Suzuki, Yuichiro

2012-01-01

256

Process for preparing pasty proteinous material or proteinous food from crustaceans  

US Patent & Trademark Office Database

According to the process of the present invention for preparing a pasty proteinous material or a proteinous food, crustaceans are boiled and milled under sufficient conditions for inactivating enzymes contained therein and then proteolytic enzyme(s) and/or micro-organism(s) are allowed to act thereon. Thus various protein sources including crustacean meat remaining in the trunks and carapaces, which have been disposed hitherto, can be efficiently utilized.

1989-04-11

257

Chemical Communication in Crustaceans: Research Challenges for the Twenty-First Century  

Microsoft Academic Search

\\u000a Chemical signals play an important role during various life stages of crustaceans. Settling of larvae, parent–offspring communication,\\u000a mate finding, mate choice, aggressive contests, and dominance hierarchies are all mediated by chemical signals. Enormous advances\\u000a have been made on understanding the function of chemical signals in crustaceans and we are on the doorstep of major advances\\u000a in chemical characterization of pheromones.

Martin Thiel; Thomas Breithaupt

258

Epipodite and fat cells as sites of hemoglobin synthesis in the branchiopod crustacean Daphnia magna  

Microsoft Academic Search

In contrast to the malacostracan crustaceans that use hemocyanin as the oxygen carrier, a number of branchiopod crustaceans,\\u000a such as the water flea Daphnia magna, utilize hemoglobin (Hb) as the respiratory protein. By means of in situ hybridization (ISH) techniques with subsequent signal\\u000a amplification using catalyzed reporter deposition, sites of Hb synthesis were localized in Daphnia magna. Based on a

Torsten Goldmann; Bertram Becher; Klaus H. Wiedorn; Ralph Pirow; Michael E. Deutschbein; Ekkehard Vollmer; Rüdiger J. Paul

1999-01-01

259

Effect of gamma radiation on membrane fluidity of MOLT-4 nuclei  

SciTech Connect

These experiments measured the effect of gamma radiation on the nuclear envelope using doxyl-fatty acid spin-label probes. Nuclei were isolated from cultured MOLT-4 cells, a radiation-sensitive human T-cell lymphocyte. Membrane fluidity was measured from the electron paramagnetic resonance spectra of the probes. MOLT-4 cells were grown under standard conditions, and suspensions were exposed to 60Co gamma radiation at room temperature. The spectra of 5-doxylstearic acid in the nuclei were those of a strongly immobilized label. A difference in the membrane fluidity was detected in a series of experiments comparing labeled irradiated and nonirradiated nuclei. The change in fluidity was measured by comparing the changes in the order parameter, S, of the spin label in irradiated nuclei with those in control nuclei. The change in the S ratio is dependent on radiation dose, increasing with doses up to 15 Gy. The maximum change of the order parameter with time after irradiation occurs 16-20 h after radiation exposure. These observations are correlated with changes in cell viabilities.

McClain, D.E.; Trypus, C.A.; May, L. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

1990-09-01

260

RNAi studies reveal a conserved role for RXR in molting in the cockroach Blattella germanica.  

PubMed

Ecdysteroids play a major role during developmental growth in insects. The more active form of these hormones, 20-hydroxyecdysone (20E), acts upon binding to its heterodimeric receptor, formed by the two nuclear receptors, EcR and RXR/USP. Functional characterization of USP has been exclusively conducted on the holometabolous insect Drosophila melanogaster. However, it has been impossible to extend such analysis to primitive-hemimetabolous insects since species of this group are not amenable to genetic analysis. The development of methodologies based on gene silencing using RNA interference (RNAi) after treatment with double-stranded RNA (dsRNA) in vivo has resolved such limitations. In this paper, we show that injection of dsRNA into the haemocoel of nymphs and adults of the cockroach Blattella germanica can be used to silence gene function in vivo. In our initial attempt to test RNAi techniques, we halted the expression of the adult-specific vitellogenin gene. We then used the same technique to silence the expression of the B. germanica RXR/USP (BgRXR) gene in vivo during the last nymphal instar. BgRXR knockdown nymphs progressed through the instar correctly but they arrested development at the end of the stage and were unable to molt into adults. The results described herein suggest that RXR/USP function, in relation to molting, is conserved across the insect Class. PMID:16427073

Martín, David; Maestro, Oscar; Cruz, Josefa; Mané-Padrós, Daniel; Bellés, Xavier

2006-01-19

261

Functional identification of the stable transfection C5aR cell line Molt-4.  

PubMed

The complement C5 anaphylatoxin receptor is a member of the seven transmembrane-spanning G protein-coupled receptor superfamily that signals through Galphai and Galpha16. C5aR is mostly expressed on neutrophils, macrophages and endothelial cells. C5a and C5aR interaction plays an important role in numerous biological effects such as in vivo cytokine storm which results in inflammatory damage. Considering the limitation of collection of human peripheral blood neutrophils and their short half life, the stably transfected cell line for studying the biological effects of C5aR is needed. In this study, we transfected C5aR gene into Molt-4 cell line and examined the function of ectopic C5aR. Our results showed stable expression of the C5aR in Molt-4 cell line and their interaction with human C5a induced ERK1/2 phosphorylation, Ca++ influx. This stable transfected cell line may provide a useful tool for studying signal pathways related to C5a and C5aR interplay and antibody development specific for C5aR. PMID:18163958

Zhang, Chunmei; Xu, Ruonan; Wang, Jianan; Han, Gencheng; Chen, Guojiang; Wang, Renxi; Wei, Huawei; Shen, Beifen; Ma, Yuanfang; Li, Yan

2007-12-01

262

Global Diversity of Marine Isopods (Except Asellota and Crustacean Symbionts)  

PubMed Central

The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa) comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10–1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species are known from the bathyal and abyssal Antarctic than Arctic GOODS provinces, and more from the larger Pacific than Atlantic oceans. Two areas with many species known are the New Zealand-Kermadec and the Northern North Pacific provinces. Deep hard substrates such as found on seamounts and the slopes are underrepresented in samples. This, the documented numbers of undescribed species in recent collections and probable cryptic species suggest a large as yet undocumented fauna, potentially an order of magnitude greater than presently known.

Poore, Gary C. B.; Bruce, Niel L.

2012-01-01

263

Global diversity of marine isopods (except Asellota and crustacean symbionts).  

PubMed

The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa) comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10-1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species are known from the bathyal and abyssal Antarctic than Arctic GOODS provinces, and more from the larger Pacific than Atlantic oceans. Two areas with many species known are the New Zealand-Kermadec and the Northern North Pacific provinces. Deep hard substrates such as found on seamounts and the slopes are underrepresented in samples. This, the documented numbers of undescribed species in recent collections and probable cryptic species suggest a large as yet undocumented fauna, potentially an order of magnitude greater than presently known. PMID:22952700

Poore, Gary C B; Bruce, Niel L

2012-08-31

264

Correlation between DNA replication and expression of cyclins A and B1 in individual MOLT-4 cells.  

PubMed

Cyclins A and B1 activate cyclin-dependent kinases CDK2 and CDC2, which regulate cell progression through S and G2. Expression of these cyclins is generally measured in populations of synchronized cells, by immunoblotting. Such studies neither provide information regarding intercellular variability in cyclin expression nor yield precise data on a time relationship between initiation and termination of DNA replication in relation to cyclin expression. Furthermore, cell synchronization by DNA polymerase inhibitors or excess of thymidine induces cell growth imbalance and alters expression of cyclins, thereby introducing an experimental bias. Using a novel flow cytometric method of detection of incorporated bromodeoxyuridine (BrdUrd) in the present study, we have been able to correlate expression of immunocytochemically discerned cyclins A and B1 with incorporation of BrdUrd and the cell cycle position of individual MOLT-4 cells. On the basis of differences in amount of incorporated BrdUrd and DNA content, the following cohorts of cells in narrow windows of the cell cycle were identified: (a) cells initiating and (b) terminating DNA replication during a 1-h pulse of BrdUrd; (c) cells replicating DNA throughout the duration of BrdUrd pulse; (d) G1 cells; and (e) G2 cells that remained in G2 for at least 1 h after exiting S phase. These populations were characterized with respect to expression of cyclins A and B1. Expression of cyclin A was an early event of S phase, and 84% of cells entering S phase during 1 h of exposure to BrdUrd were already cyclin A positive. More than 95% of S-phase cells, as well as the cells exiting S during BrdUrd pulse, were also cyclin A positive. The maximal rate of accumulation of cyclin A was seen during the first hour of progression through S phase. In contrast, the maximal accumulation rate of cyclin B1 showed cells during the first hour of progression through G2. A strong correlation between expression of cyclin A and the rate of DNA replication, estimated by the degree of BrdUrd incorporation (r = 0.99), was observed. PMID:9041174

Juan, G; Li, X; Darzynkiewicz, Z

1997-03-01

265

Neurogenesis in the central olfactory pathway of adult decapod crustaceans: development of the neurogenic niche in the brains of procambarid crayfish  

PubMed Central

Background In the decapod crustacean brain, neurogenesis persists throughout the animal's life. After embryogenesis, the central olfactory pathway integrates newborn olfactory local and projection interneurons that replace old neurons or expand the existing population. In crayfish, these neurons are the descendants of precursor cells residing in a neurogenic niche. In this paper, the development of the niche was documented by monitoring proliferating cells with S-phase-specific markers combined with immunohistochemical, dye-injection and pulse-chase experiments. Results Between the end of embryogenesis and throughout the first post-embryonic stage (POI), a defined transverse band of mitotically active cells (which we will term 'the deutocerebral proliferative system' (DPS) appears. Just prior to hatching and in parallel with the formation of the DPS, the anlagen of the niche appears, closely associated with the vasculature. When the hatchling molts to the second post-embryonic stage (POII), the DPS differentiates into the lateral (LPZ) and medial (MPZ) proliferative zones. The LPZ and MPZ are characterized by a high number of mitotically active cells from the beginning of post-embryonic life; in contrast, the developing niche contains only very few dividing cells, a characteristic that persists in the adult organism. Conclusions Our data suggest that the LPZ and MPZ are largely responsible for the production of new neurons in the early post-embryonic stages, and that the neurogenic niche in the beginning plays a subordinate role. However, as the neuroblasts in the proliferation zones disappear during early post-embryonic life, the neuronal precursors in the niche gradually become the dominant and only mechanism for the generation of new neurons in the adult brain.

2012-01-01

266

Epstein-Barr virus infectivity of Raji and Molt 4 cells: differences in cellular membrane lipids and apparent microviscosity.  

PubMed

Infection of lymphocytes by the Epstein-Barr virus (EBV) is initiated by attachment of the major virus glycoprotein gp350/220 to a cell surface glycoprotein, known as CR2 (CD21). In a productive infection the virus envelope fuses with host cell membranes either at the cell surface or within endocytic vesicles. To investigate the relevance of host cell membrane properties in the fusion process, we used the lymphoblastoid cell lines Raji and Molt 4. Both cell lines express CR2 and bind EBV; however, only the Raji cell supports virus-cell fusion. Lipid analysis of the two cell lines indicated that Raji cells had a significantly lower cholesterol to phospholipid molar ratio due to a greater membrane content of phospholipid relative to protein. Determination of cell membrane fluid dynamics by fluorescence polarization indicated that the apparent membrane microviscosity of Molt 4 cells was significantly greater than that of Raji. Increasing Raji cell membrane apparent microviscosity to values similar to those of Molt 4 cells by incubation with cholesteryl-hemisuccinate caused a reduction in EBV fusion with Raji cells. However, experiments designed to allow EBV infection of Molt 4 cells whose plasma membranes had been fluidized were unsuccessful. These studies suggest that the lipid composition and other as yet unidentified factors are involved in entry of EBV into cells. PMID:8391180

Patel, R A; Hutt-Fletcher, L M; Crews, F T

1993-07-01

267

Retention of the cucurbit yellow vine disease bacterium, Serratia marcescens, through transstadial molt of the vector, Anasa tristis (Hemiptera: Coreidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Retention or loss of transmissibility after molting was tested for adult and nymphal stages of the squash bug, Anasa tristis DeGeer, a natural vector of the plant pathogen, Serratia marcescens Bizio, the causal agent of cucurbit yellow vine disease. Squash bug adults and nymphs fed from bacteria-i...

268

Crustacean social behavioral changes in response to isolation.  

PubMed

Periods of isolation during which animals have no social contact are common in the design of behavioral experiments. They are used, for example, to test memory and recognition responses, or to ensure a baseline condition before experimental manipulations commence. We investigated the effect of isolation periods on the aggressive behavior of matched pairs of the crayfish Cherax destructor in two contexts. The first experiment tested the effects of a period of isolation between two encounters. The second experiment tested the effects of isolation before an encounter by pairing one crayfish from a communal living environment with another crayfish from an isolated one. Fight outcome and aggression levels were analyzed, resulting in three conclusions about the social biology of C. destructor. First, encounters between familiar opponents are influenced by the outcome of the familiarization fight for about 2 weeks. Second, the level of aggression and the outcome of an encounter are affected over different time frames. Third, individuals that are isolated before an encounter can be disadvantaged. These data suggest that isolation, or events that occur during periods of isolation, affect multiple elements of social behavior in C. destructor. This suggestion has implications for the interpretation of previous results and future studies in crustaceans and other taxa. PMID:17928525

Hemsworth, Robert; Villareal, Wil; Patullo, Blair W; MacMillan, David L

2007-10-01

269

Evolution and development in cave animals: from fish to crustaceans  

PubMed Central

Cave animals are excellent models to study the general principles of evolution as well as the mechanisms of adaptation to a novel environment: the perpetual darkness of caves. In this article, two of the major model systems used to study the evolution and development (evo–devo) of cave animals are described: the teleost fish Astyanax mexicanus and the isopod crustacean Asellus aquaticus. The ways in which these animals match the major attributes expected of an evo–devo cave animal model system are described. For both species, we enumerate the regressive and constructive troglomorphic traits that have evolved during their adaptation to cave life, the developmental and genetic basis of these traits, the possible evolutionary forces responsible for them, and potential new areas in which these model systems could be used for further exploration of the evolution of cave animals. Furthermore, we compare the two model cave animals to investigate the mechanisms of troglomorphic evolution. Finally, we propose a few other cave animal systems that would be suitable for development as additional models to obtain a more comprehensive understanding of the developmental and genetic mechanisms involved in troglomorphic evolution.

Protas, Meredith; Jeffery, William R.

2013-01-01

270

Evolution and development in cave animals: from fish to crustaceans.  

PubMed

Cave animals are excellent models to study the general principles of evolution as well as the mechanisms of adaptation to a novel environment: the perpetual darkness of caves. In this article, two of the major model systems used to study the evolution and development (evo-devo) of cave animals are described: the teleost fish Astyanax mexicanus and the isopod crustacean Asellus aquaticus. The ways in which these animals match the major attributes expected of an evo-devo cave animal model system are described. For both species, we enumerate the regressive and constructive troglomorphic traits that have evolved during their adaptation to cave life, the developmental and genetic basis of these traits, the possible evolutionary forces responsible for them, and potential new areas in which these model systems could be used for further exploration of the evolution of cave animals. Furthermore, we compare the two model cave animals to investigate the mechanisms of troglomorphic evolution. Finally, we propose a few other cave animal systems that would be suitable for development as additional models to obtain a more comprehensive understanding of the developmental and genetic mechanisms involved in troglomorphic evolution. PMID:23580903

Protas, Meredith; Jeffery, William R

271

Photosensitive neurogenic heart of the isopod crustacean Ligia exotica.  

PubMed

The heart of animals is regulated through the central nervous system in response to external sensory stimuli. We found, however, that the adult neurogenic heart of the isopod crustacean Ligia exotica has photosensitivity. The beat frequency of the isolated heart decreased in response to a light stimulus. Magnitude of the response was stimulus intensity dependent and the heartbeat frequency decreased to less than 80% of the dark value during illumination of the white light with an intensity of 6.0 mW cm-2. The spectral sensitivity curve of the heart photoresponse peaked at a wavelength around 520 nm. In response to 530 nm monochromatic light, the relationship between light intensity and response magnitude was linear and the threshold intensity was 7.26 x 1012 quanta cm-2 s-1. Bursting activity of the cardiac ganglion, which is located in the heart and acts as the cardiac pacemaker deceased in frequency in response to illumination by white light. This fact suggests that the heart photoresponse of L. exotica results from the photosensitivity of the cardiac ganglion neurons. The photoresponse of the heart therefore contributes to regulation of cardiac output in addition to other regulatory systems. PMID:16959646

Miyamoto, Hiroshi; Horiguchi, Hiroko; Hariyama, Takahiko; Takano, Satoshi; Yamagishi, Hiroshi

2006-10-01

272

Kinetic properties of hexameric tyrosinase from the crustacean Palinurus elephas.  

PubMed

Tyrosinases catalyze hydroxylation of monophenols to o-diphenols and their subsequent oxidation to o-quinones, whereas catecholoxidases catalyze only the latter reaction. Both enzymes occur in all organisms and are Type 3 copper proteins that perform the first steps of melanin formation. In arthropods, they play an essential role in the sclerotization of the exoskeleton. Very few phenoloxidases are characterized structurally or kinetically and the existence of an actual tyrosinase activity has not been demonstrated in most cases. Here we present for the first time a complete kinetic characterization of a tyrosinase from a crustacean (Palinurus elephas) including the influence of inhibitors. In contrast to most tyrosinases which are monomeric or dimeric, this tyrosinase occurs as a hexamer. However, the data did not indicate cooperativity in steady-state kinetics for the two substrates used, the monophenol tyramine and the diphenol dopamine. Mimosine as well as phenylthiourea (PTU) inhibited both monophenolhydroxylase and diphenoloxidase activity. Inhibition by mimosine was competitive, whereas PTU was a noncompetitive inhibitor. Furthermore, for the diphenolase activity substrate inhibition was observed, which was apparently abolished by adding PTU. These observations lead to the hypothesis that a secondary, allosteric binding site exists, which binds dopamine and PTU and reduces the catalytic activity. PMID:18422877

Brack, Antje; Hellmann, Nadja; Decker, Heinz

2008-04-12

273

Photosensitive neurogenic heart of the isopod crustacean Ligia exotica  

PubMed Central

The heart of animals is regulated through the central nervous system in response to external sensory stimuli. We found, however, that the adult neurogenic heart of the isopod crustacean Ligia exotica has photosensitivity. The beat frequency of the isolated heart decreased in response to a light stimulus. Magnitude of the response was stimulus intensity dependent and the heartbeat frequency decreased to less than 80% of the dark value during illumination of the white light with an intensity of 6.0?mW?cm?2. The spectral sensitivity curve of the heart photoresponse peaked at a wavelength around 520?nm. In response to 530?nm monochromatic light, the relationship between light intensity and response magnitude was linear and the threshold intensity was 7.26×1012?quanta?cm?2?s?1. Bursting activity of the cardiac ganglion, which is located in the heart and acts as the cardiac pacemaker deceased in frequency in response to illumination by white light. This fact suggests that the heart photoresponse of L. exotica results from the photosensitivity of the cardiac ganglion neurons. The photoresponse of the heart therefore contributes to regulation of cardiac output in addition to other regulatory systems.

Miyamoto, Hiroshi; Horiguchi, Hiroko; Hariyama, Takahiko; Takano, Satoshi; Yamagishi, Hiroshi

2006-01-01

274

Molting-specific downregulation of C. elegans body-wall muscle attachment sites: the role of RNF-5 E3 ligase.  

PubMed

Repeated molting of the cuticula is an integral part of arthropod and nematode development. Shedding of the old cuticle takes place on the surface of hypodermal cells, which are also responsible for secretion and synthesis of a new cuticle. Here, we use the model nematode Caenorhabditis elegans to show that muscle cells, laying beneath and mechanically linked to the hypodermis, play an important role during molting. We followed the molecular composition and distribution of integrin mediated adhesion structures called dense bodies (DB), which indirectly connect muscles to the hypodermis. We found the concentration of two DB proteins (PAT-3/beta-integrin and UNC-95) to decrease during the quiescent phase of molting, concomitant with an apparent increase in lateral movement of the DB. We show that levels of the E3-ligase RNF-5 increase specifically during molting, and that RNF-5 acts to ubiquitinate the DB protein UNC-95. Persistent high levels of RNF-5 driven by a heatshock or unc-95 promoter lead to failure of ecdysis, and in non-molting worms to a progressive detachment of the cuticle from the hypodermis. These observations indicate that increased DB dynamics characterizes the lethargus phase of molting in parallel to decreased levels of DB components and that temporal expression of RNF-5 contributes to an efficient molting process. PMID:20385102

Zaidel-Bar, Ronen; Miller, Shahar; Kaminsky, Rachel; Broday, Limor

2010-04-10

275

Using body mass dynamics to examine long-term habitat shifts of arctic-molting geese: Evidence for ecological change  

USGS Publications Warehouse

From 1976 onward, molting brant geese (Branta bernicla) within the Teshekpuk Lake Special Area, Alaska, shifted from inland, freshwater lakes toward coastal wetlands. Two hypotheses explained this redistribution: (1) ecological change: redistribution of molting brant reflects improvements in coastal foraging habitats, which have undergone a succession toward salt-tolerant plants due to increased coastal erosion and saltwater intrusion as induced by climate change or (2) interspecific competition: greater white-fronted geese (Anser albifrons) populations increased 12-fold at inland lakes, limiting food availability and forcing brant into coastal habitats. Both hypotheses presume that brant redistributions were driven by food availability; thus, body mass dynamics may provide insight into the relevance of these hypotheses. We compared body mass dynamics of molting brant across decades (1978, 1987–1992, 2005–2007) and, during 2005–2007, across habitats (coastal vs. inland). Brant lost body mass during molt in all three decades. At inland habitats, rates of mass loss progressively decreased by decade despite the increased number of greater white-fronted geese. These results do not support an interspecific competition hypothesis, instead suggesting that ecological change enhanced foraging habitats for brant. During 2005–2007, rates of mass loss did not vary by habitat. Thus, while habitats have improved from earlier decades, our results cannot distinguish between ecological changes at inland versus coastal habitats. However, we speculate that coastal forage quality has improved beyond that of inland habitats and that the body mass benefits of these higher quality foods are offset by the disproportionate number of brant now molting coastally.

Lewis, Tyler L.; Flint, Paul L.; Derksen, Dirk V.; Schmutz, Joel A.; Taylor, Eric J.; Bollinger, Karen S.

2011-01-01

276

Daphnia Halloween genes that encode cytochrome P450s mediating the synthesis of the arthropod molting hormone: Evolutionary implications  

PubMed Central

Background In crustaceans and insects, development and reproduction are controlled by the steroid hormone, 20-hydroxyecdysone (20E). Like other steroids, 20E, is synthesized from cholesterol through reactions involving cytochrome P450s (CYPs). In insects, the CYP enzymes mediating 20E biosynthesis have been identified, but evidence of their probable presence in crustaceans is indirect, relying solely on the ability of crustaceans to synthesize 20E. Results To investigate the presence of these genes in crustaceans, the genome of Daphnia pulex was examined for orthologs of these genes, the Halloween genes, encoding those biosynthetic CYP enzymes. Single homologs of spook-CYP307A1, phantom-CYP306A1, disembodied-CYP302A1, shadow-CYP315A1 and shade-CYP314A1 were identified in the Daphnia data base. Phylogenetic analysis indicates an orthologous relationship between the insect and Daphnia genes. Conserved intron/exon structures and microsynteny further support the conclusion that these steroidogenic CYPs have been conserved in insects and crustaceans through some 400 million years of evolution. Conclusion Although these arthropod steroidogenic CYPs are related to steroidogenic CYPs in Caenorhabditis elegans and vertebrates, the data suggest that the arthropod steroidogenic CYPs became functionally specialized in a common ancestor of arthropods and are unique to these animals.

2008-01-01

277

Effects of alfalfa and fructooligosaccharide on molting parameters and bone qualities using dual energy X-ray absorptiometry and conventional bone assays.  

PubMed

The aim of this study was to evaluate effects of alfalfa and fructooligosaccharides (FOS) on molting performance and bone parameters compared with the conventional feed withdrawal molting procedure. A total of 36 Single Comb White Leghorn hens (84 wk of age) were used for this experiment. The hens were divided into 6 treatment groups with 6 birds per treatment: pre-trial control (PC), full fed (FF), feed withdrawal (FW), 100% alfalfa (A100), A100 + 0.375% FOS (A100L), and A100 + 0.75% FOS (A100H). At the end of the 9-d molt period, hens were euthanized, and tibia and femurs were collected to evaluate bone qualities using dual-energy x-ray absorptiometry (DXA), Instron (Model 1011 Instron Universal Testing Machine, Instron Corp., Canton. MA), and conventional bone assays. Egg production was recorded during the molting period to evaluate first day out of production, and ovary was also collected to measure ovary weight. Alfalfa molting diets had comparable molting parameters, such as percentage of BW loss, ovary weight, and first day out of egg production, to the conventional feed withdrawal molting procedure, and FOS supplementation did not have any detrimental effects on molting performance. Conventional bone assay and DXA results suggest that hens lose a considerable amount of bone minerals during a molting period. The tibia and femur bone strengths of the FF, FW, A100, and A100L hens were significantly lower than the PC hens, whereas hens fed A100H had similar tibia bone breaking strength to that of the PC hens. The bone parameters measured by conventional assays, bone breaking strength measured by Instron, and bone density and mineral content measured by DXA were highly correlated to each other. PMID:16493940

Kim, W K; Donalson, L M; Mitchell, A D; Kubena, L F; Nisbet, D J; Ricke, S C

2006-01-01

278

RNA interference to reveal roles of ?-N-acetylglucosaminidase gene during molting process in Locusta migratoria.  

PubMed

?-N-acetylglucosaminidases are crucial enzymes involved in chitin degradation in insects. We identified a ?-N-acetylglucosaminidase gene (LmNAG1) from Locusta migratoria. The full-length complementary DNA (cDNA) of LmNAG1 consists of 2 667 nucleotides, including an open reading frame (ORF) of 1 845 nucleotides encoding 614 amino acid residues, and 233- and 589-nucleotide non-coding regions at the 5'- and 3'-ends, respectively. Phylogenetic analysis grouped the cDNA-deduced LmNAG1 protein with the enzymatically characterized ?-N-acetylglucosaminidases in group I. Analyses of stage- and tissue-dependent expression patterns of LmNAG1 were carried out by real-time quantitative polymerase chain reaction. Our results showed that LmNAG1 transcript level in the integument was significantly high in the last 2 days of the fourth and fifth instar nymphs. LmNAG1 was highly expressed in foregut and hindgut. RNA interference of LmNAG1 resulted in an effective silence of the gene and a significantly reduced total LmNAG enzyme activity at 48 and 72 h after the injection of LmNAG1 double-stranded RNA (dsRNA). As compared with the control nymphs injected with GFP dsRNA, 50% of the dsLmNAG1-injected nymphs were not able to molt successfully and eventually died. Our results suggest that LmNAG1 plays an essential role in molting process of L. migratoria. PMID:23955831

Rong, Shuo; Li, Da-Qi; Zhang, Xue-Yao; Li, Sheng; Zhu, Kun Yan; Guo, Ya-Ping; Ma, En-Bo; Zhang, Jian-Zhen

2012-11-22

279

Scale-dependent analysis of an otter-crustacean system in Argentinean Patagonia  

NASA Astrophysics Data System (ADS)

The Southern river otter or ‘huillin’, Lontra provocax, is an endangered species endemic of the Andean Patagonian region of Argentina and Chile. It feeds almost exclusively on the genera of macro-crustacea: Aegla and Sammastacus. The aim of this study was to analyse the role of food availability on the huillin’s distribution using a scale-dependent analysis of crustacean and otter distributions. We compared the distributions of otters and macro-crustaceans along a north-south regional gradient, between river basins of northern Patagonia, in an altitudinal gradient within a river basin, and between habitat types within a lake. We investigated the distribution of otters by sign surveys along lake shores, river banks and marine coasts, and of crustaceans using surveys in the water, undigested remains in mink ( Mustela vison) scats, presence of external skeletons at the waterside and through interviews with local people. Our results show that there were heterogeneities in the distributions of macro-crustaceans at four scales and these were generally reflected in the distributions of freshwater otters. We conclude that the main factor limiting the distributions of L. provocax in freshwater environments is the availability of macro-crustaceans. This paper shows how scale-dependent type analyses of population distribution serves as a method for identifying key environmental factors for species for which the use of long-term demographies is unfeasible.

Cassini, Marcelo H.; Fasola, Laura; Chehébar, Claudio; MacDonald, David W.

2009-05-01

280

Temporal dynamics of convergent modulation at a crustacean neuromuscular junction.  

PubMed

At least 10 different substances modulate the amplitude of nerve-evoked contractions of the gastric mill 4 (gm4) muscle of the crab, Cancer borealis. Serotonin, dopamine, octopamine, proctolin, red pigment concentrating hormone, crustacean cardioactive peptide, TNRNFLRFamide, and SDRNFLRFamide increased and -allatostatin-3 and histamine decreased the amplitude of nerve-evoked contractions. Modulator efficacy was frequency dependent; TNRNFLRFamide, proctolin, and allatostatin-3 were more effective when the motor neuron was stimulated at 10 Hz than at 40 Hz, whereas the reverse was true for dopamine and serotonin. The modulators that were most effective at high stimulus frequencies produced a significant decrease in muscle relaxation time; those that were most effective at low stimulus frequencies produced modest increases in relaxation time. Thus modulator actions that appear redundant when examined only at one stimulus frequency are differentiated when a range of stimulus dynamics is studied. The effects of TNRNFLRFamide, serotonin, proctolin, dopamine, and -allatostatin-3 on the amplitude and facilitation of nerve-evoked excitatory junctional potentials (EJPs) in the gm4 and gastric mill 6 (gm6) muscles were compared. The EJPs in gm4 have a large initial amplitude and show relatively little facilitation, whereas the EJPs in gm6 have a small initial amplitude and show considerable facilitation. Modulators that enhanced contractions also enhanced EJP amplitude; -allatostatin-3 reduced EJP amplitude. The effects of these modulators on EJP amplitude were modest and showed no significant frequency dependence. This suggests that the frequency dependence of modulator action on contraction results from effects on excitation-contraction coupling. The modulators affected facilitation at these junctions in a manner consistent with a change in release probability. They produced a change in facilitation that is inversely related to their action on EJP amplitude. PMID:9819263

Jorge-Rivera, J C; Sen, K; Birmingham, J T; Abbott, L F; Marder, E

1998-11-01

281

Behavioural, ventilatory and respiratory responses of epigean and hypogean crustaceans to different temperatures.  

PubMed

Impact of temperature (from -2 to 28 degrees C) on survival, oxygen consumption, locomotory and ventilatory activities was measured in two aquatic subterranean crustaceans (Niphargus rhenorhodanensis and Niphargus virei) and in a morphologically close surface-dwelling crustacean (Gammarus fossarum). The hypogean N. virei presented all characteristics of a stenothermal organism: it showed small thermal plasticity and optimised its performance on a narrow range of temperature. In contrast, the epigean G. fossarum and more surprisingly the hypogean N. rhenorodanensis can be both characterized as eurythermal organisms: they exhibited important survival times and conserved their performance optimum throughout a large range of temperature. Such differences of survival and performance patterns in two hypogean organisms were unexpected since they both live in very thermally buffered biotopes. Our data suggest fresh hypotheses about the role of glaciations in the history and adaptation of hypogean crustaceans. PMID:15893488

Issartel, Julien; Hervant, Frédéric; Voituron, Yann; Renault, David; Vernon, Philippe

2005-05-01

282

Characteristics and value of the Thukela Banks crustacean and linefish fisheries, and the potential impacts of changes in river flow  

Microsoft Academic Search

This study describes the Thukela Banks crustacean and linefish fisheries and investigates the potential impacts of reduced flow from the Thukela River on the value of these fisheries. Data were obtained from published and unpublished material, key informants and government records. The crustacean fishery employs about 300 people, and comprises an inshore and offshore fishery. Inshore catches and effort are

J K Turpie; S J Lamberth

2010-01-01

283

Coping with extreme: highland eurasian tree sparrows with molt-breeding overlap express higher levels of corticoserone-binding globulin than lowland sparrows.  

PubMed

In birds, suppressed expression of stress-induced corticosterone (CORT) during pre-basic molt is generally thought to reflect a physiological trade-off in self-maintenance. And reduced CORT during breeding in extreme environments may maximize reproductive success and optimize their fitness. Highland Eurasian tree sparrows (Passer montanus) are known to express significantly higher stress-induced CORT levels during the pre-basic molt stage. Here, we show that these highland sparrows are characterized by a life history strategy of molt-breeding overlap, with higher corticosterone-binding globulin (CBG) levels favoring molt and breeding consistent with fitness optimization on the Tibetan Plateau. These unique behavioral and physiological strategies reflect natural selection under strong evolutionary pressures in extreme high-altitude environments. J. Exp. Zool. 319A: 482-486, 2013. © 2013 Wiley Periodicals, Inc. PMID:23847036

Li, Dongming; Zhang, Ji; Liu, Dan; Zhang, Li; Hu, Yonghong; Duan, Xianglin; Wu, Yuefeng

2013-07-11

284

Ontogeny of behavioural adaptations in beach crustaceans: some temporal considerations for integrated coastal zone management and conservation  

NASA Astrophysics Data System (ADS)

So-called "typical" behavioural responses of coastal animals to particular stimuli have previously been shown often to vary cyclically in phase with diel or tidal cycles in the environment. Less well-studied are differences in the behaviour of adults and juveniles of the same species at the same time of day or tidal state, or in response to the same stimulus. Experimental studies of such differences in behaviour are reviewed and compared for three species of beach crustaceans, namely, the crab Carcinus maenas, the isopod Eurydice pulchra and the amphipod Orchestoidea tuberculata. Juvenile, but not adult, Carcinus will entrain circatidal rhythmicity after exposure to artificial tidal cycles of immersion/emersion; juvenile, but not adult, Eurydice express pronounced free-running circatidal swimming rhythms at neap tides as well as at springs; and, in Orchestoidea, juveniles and adults express patterns of daily locomotor activity that are complementary, both on the shore and in the laboratory. These ontogenetic differences are discussed in relation to distributional and behavioural differences between adults and juveniles in each species, drawing attention to their adaptive significance and wider implications for coastal management and conservation.

Naylor, E.; Kennedy, F.

2003-10-01

285

A gene family of cathepsin L-like proteases of filarial nematodes are associated with larval molting and cuticle and eggshell remodeling  

Microsoft Academic Search

Cysteine proteinases are involved in a variety of important biological processes and have been implicated in molting and tissue remodeling in free living and parasitic nematodes. We show that in the lymphatic filarial nematode Brugia pahangi molting of third-stage larvae (L3) to fourth-stage larvae is dependent on the activity of a cathepsin L-like cysteine protease (CPL), which can be detected

David B. Guiliano; Xiqiang Hong; James H. McKerrow; Mark. L. Blaxter; Yelena Oksov; Jing Liu; Elodie Ghedin; Sara Lustigman

2004-01-01

286

A novel lignan composition from Cedrus deodara induces apoptosis and early nitric oxide generation in human leukemia Molt4 and HL60 cells  

Microsoft Academic Search

AP9-cd, a standardized lignan composition from Cedrus deodara consisting of (?)-wikstromal, (?)-matairesinol, and dibenzyl butyrolactol, showed cytotoxicity in several human cancer cell lines reported earlier. An attempt was made in this study to investigate the mechanism of cell death in human leukemia Molt-4 and HL-60 cells. It inhibited Molt-4 cell proliferation with 48-h IC50 of ?15?g\\/ml, increased sub-G0 cell fraction

Bhushan Shashi; Singh Jaswant; Rao J. Madhusudana; Saxena A. Kumar; Qazi G. Nabi

2006-01-01

287

Involvement of SAPK\\/JNK pathway in X-ray-induced rapid cell death of human T-cell leukemia cell line MOLT4  

Microsoft Academic Search

We found that SAPK\\/JNK was phosphorylated during X-ray-induced rapid cell death of MOLT-4 cells and that acid Sphingomyelinase inhibitor D609 suppressed the rapid cell death as well as phosphorylation of SAPK\\/JNK. Also C2-ceramide caused phosphorylation of SAPK\\/JNK, followed by rapid cell death. Further we isolated X-ray-resistant radiation-hybrid clones from MOLT-4 and 50 Gy irradiated mouse FM3A cells by repeated selections

Atsushi Enomoto; Norio Suzuki; Kazuya Hirano; Yoshihisa Matsumoto; Akinori Morita; Kazuo Sakai; Hideki Koyama

2000-01-01

288

Induction of multidrug resistance in MOLT4 cells by anticancer agents is closely related to increased expression of functional P-glycoprotein and MDR1 mRNA  

Microsoft Academic Search

Purpose: The aim of this study was to investigate the multidrug resistance (MDR) pattern, MDR gene and P-glycoprotein (P-gp) expression, and P-gp function in drug-induced human T-lymphoblastoid leukemia MOLT-4 sublines. Methods: The MDR sublines were developed by exposing the parental MOLT-4 cells to stepwise increasing concentrations of anticancer drugs daunorubicin (DNR), vinblastine (VBL) and doxorubicin (DOX). Degrees of resistance were

Zhen-Li Liu; Kenji Onda; Sachiko Tanaka; Tsugutoshi Toma; Toshihiko Hirano; Kitaro Oka

2002-01-01

289

Cytotoxicity of Dihydroartemisinin Toward Molt-4 Cells Attenuated by N-Tert-butyl-alpha-phenylnitrone and Deferoxamine.  

PubMed

Derivatives of artemisinin, a compound extracted from the wormwood Artemisia annua L, have potent anticancer properties. The anticancer mechanisms of artemisinin derivatives have not been fully-elucidated. We hypothesize that the cytotoxicity of these compounds is due to the free radicals formed by interaction of their endoperoxide moiety with intracellular iron in cancer cells. The effects of N-tert-butyl-alpha-phenylnitrone (PBN), a spin-trap free radical scavenger, and deferoxamine (DX), an iron chelating agent, on the in vitro cytotoxicity of dihyroartemisinin (DHA) toward Molt-4 human T-lymphoblastoid leukemia cells were investigated in the present study. Dihydroartemisinin effectively killed Molt-4 cells in vitro. Its cytotoxicity was significantly attenuated by PBN and DX. Based on the data of our present and previous studies, we conclude that one anticancer mechanism of dihydroartemisinin is the formation of toxic-free radicals via an iron-mediated process. PMID:24123007

Chan, Ho Wing; Singh, Narendra P; Lai, Henry C

2013-10-01

290

Recruitment patterns of decapod crustacean megalopae in a shallow inlet (SW Spain) related to life history strategies  

NASA Astrophysics Data System (ADS)

Decapod crustacean megalopae were sampled weekly (spring/neap tides) during late-spring/summer of 1998 by using two planktonic nets located close to the surface and the bottom, at a fixed station in the mouth of the R?´o San Pedro inlet (SW Spain). Sampling was carried out during 25 h cycles to ascertain the flux of megalopae in relation to the main environmental (diel, tidal, tidal amplitude) cycles. The hypothesis that megalopae of some species may be using tidal-stream transport as a mechanism of re-invading the inlet was tested and the relationship between megalopal behaviour and life history strategy was analysed. In general, the flux of megalopae was higher during spring tides, but such differences were only statistically significant for Pisidia longicornis and Liocarcinus sp.2 due to the considerable interdate variation. With the exception of Macropodia sp., megalopae were more abundant close to the bottom. The diel/tidal flux of most abundant species suggested two different patterns of behaviour: megalopae of Liocarcinus spp., Panopeus africanus, Uca tangeri and Brachynotus sexdentatus seemed to be re-invading the inlet (specially at nocturnal floods), while megalopae of Ilia nucleus, Nepinnotheres pinnotheres and Macropodia sp. may have been just looking for a suitable place for settlement. The first group corresponded to the species whose zoeal development occurs in open sea, and the second one to species that complete their life cycle within the studied system, suggesting a relationship between the duration of the larval phase and the life cycle strategy of the species.

González-Gordillo, J. I.; Arias, A. M.; Rodr?´guez, A.; Drake, P.

2003-03-01

291

Size and temperature-dependent variations in intermolt duration and size increment at molt of Northern Shrimp, Pandalus borealis  

Microsoft Academic Search

Growth of Pandalus borealis post-larval stages was measured in relation to size and temperature. Growth characteristics, including intermolt period (IP),\\u000a molt increment (MI) in size and mass, and tissue allocation in juvenile, male, and female shrimp, were evaluated at 2, 5,\\u000a and 8°C, the temperature range where this species is generally found in the Northwest Atlantic. Significant variations in\\u000a growth

Dounia Daoud; Yvan Lambert; Céline Audet; Denis Chabot

2010-01-01

292

Juvenile hormone acts at embryonic molts and induces the nymphal cuticle in the direct-developing cricket.  

PubMed

During embryogenesis of hemimetabolous insects, the sesquiterpenoid hormone, juvenile hormone (JH), appears late in embryogenesis coincident with formation of the first nymphal cuticle. We tested the role of embryonic JH by treating cricket embryos with JH III, or the JH-mimic (JHM) pyriproxifen, during early embryogenesis. We found two discrete windows of JH sensitivity. The first occurs during the formation of the first (E1) embryonic cuticle. Treatment with JHM prior to this molt produced small embryos that failed to complete the movements of katatrepsis. Embryos treated after the E1 molt but before the second embryonic (pronymphal) molt completed katatrepsis but then failed to complete dorsal closure and precociously formed nymphal, rather than pronymphal characters. This second sensitivity window was further assessed by treating embryos with low doses of JH III prior to the pronymphal molt. With low doses, mosaic cuticles were formed, bearing features of both the pronymphal and nymphal stages. The nymphal characters varied in their sensitivity to JH III, due at least in part to differences in the timing of their sensitivity windows. Unexpectedly, many of the JH III-treated embryos with mosaic and precocious nymphal cuticles made a second nymphal cuticle and successfully hatched. JH treatment also affected the growth of the embryos. By focusing on the developing limb, we found that the effect of JH upon growth was asymmetric, with distal segments more affected than proximal ones, but this was not reflected in misexpression of Distal-less or Bric-a-brac, which are involved in proximal-distal patterning of the limb. PMID:15170568

Erezyilmaz, Deniz F; Riddiford, Lynn M; Truman, James W

2004-05-29

293

Both UDP N-acetylglucosamine pyrophosphorylases of Tribolium castaneum are critical for molting, survival and fecundity.  

PubMed

A bioinformatics search of the genome of the red flour beetle, Tribolium castaneum, resulted in the identification of two genes encoding proteins closely related to UDP-N-acetylglucosamine pyrophosphorylases (UAPs), which provide the activated precursor, UDP-N-acetylglucosamine, for the synthesis of chitin, glycoproteins and glycosylphosphoinositide (GPI) anchors of some membrane proteins as well as for the modification of other substrates. This is in contrast to other arthropods whose genomes have been completely sequenced, all of which have only a single copy of this gene. The two T. castaneum UAP genes, TcUAP1 and TcUAP2, share both nucleotide and amino acid sequence identities of about 60%. RT-PCR analysis revealed that the two genes differ in their developmental and tissue-specific patterns of expression. RNA interference (RNAi) indicated roles for TcUAP1 and TcUAP2 at the molt and intermolt stages, respectively: RNAi for TcUAP1 resulted in specific arrest at the larval-larval, larval-pupal or pupal-adult molts, depending on time of injection of double-stranded RNAs, whereas RNAi for TcUAP2 prevented larval growth or resulted in pupal paralysis. Analysis of elytral cuticle indicated loss of structural integrity and chitin staining after RNAi for TcUAP1, but not after RNAi for TcUAP2. Loss of peritrophic matrix (PM)-associated chitin was also observed following RNAi for TcUAP1, but not after RNAi for TcUAP2. Down-regulation of transcripts for either TcUAP gene at the mature adult stage resulted in cessation of oviposition in females, as well as fat body depletion and eventual death in both sexes. These results demonstrate that both TcUAP genes are critical for beetle development and survival, but that only TcUAP1 is clearly associated with synthesis of cuticular or PM chitin. However, both of these genes appear to have additional critical role(s) unrelated to chitin synthesis, presumably in the glycosylation of proteins and/or secondary metabolites. PMID:20920581

Arakane, Yasuyuki; Baguinon, Marilyn C; Jasrapuria, Sinu; Chaudhari, Sujata; Doyungan, Alison; Kramer, Karl J; Muthukrishnan, Subbaratnam; Beeman, Richard W

2010-10-27

294

Binding affinity of nonsteroidal ecdysone agonists against the ecdysone receptor complex determines the strength of their molting hormonal activity.  

PubMed

N-tert-Butyl-N,N'-dibenzoylhydrazine and its analogs are nonsteroidal ecdysone agonists that exhibit insect molting hormonal and larvicidal activities. The interaction mode of those ecdysone agonists with the heterodimer of the ecdysone receptor and ultraspiracle has not been fully elucidated. We expressed the ecdysone receptor B1 and the ultraspiracle of the lepidopteran, Chilo suppressalis, using an in vitro transcription/translation system and confirmed, using gel-shift assays, that the proteins function as ecdysone receptors. We also analyzed their ligand-binding affinity. A potent ecdysteroid, ponasterone A, specifically bound to the ecdysone receptor with low affinity (KD = 55 nm), and the specific binding was dramatically increased (KD = 1.2 nm) in the presence of the ultraspiracle. For seven nonsteroidal ecdysone agonists and five ecdysteroids, the binding activity to the in vitro-translated ecdysone receptor-ultraspiracle complex was linearly correlated with the binding activity to the inherent receptor protein in the cell-free preparation of C. suppressalis integument. The binding to the ecdysone receptor-ultraspiracle complex for a series of compounds was highly correlated with their molting hormonal activity, indicating that the binding affinity of nonsteroidal ecdysone agonists to the ecdysone receptor-ultraspiracle complex primarily determines the strength of their molting hormonal activity. PMID:14519121

Minakuchi, Chieka; Nakagawa, Yoshiaki; Kamimura, Manabu; Miyagawa, Hisashi

2003-10-01

295

Radiation-induced association of beta-glucuronidase with purified nuclei from irradiated MOLT-4 and HeLa cells  

SciTech Connect

Beta-glucuronidase, a lysosomal marker enzyme, associates with purified nuclei from HeLa and MOLT-4 cell lines in a radiation dose-dependent manner, up to 300 cGy in MOLT-4 cells, and 1000 cGy in HeLa cells. In MOLT-4 cells (200-cGy exposure), there is a significant increase in beta-glucuronidase activity detected in the nuclear fraction 24 h postirradiation with a maximum association occurring at 72 h. In HeLa cells (1000-cGy exposure), a significant association is first detected 24 h postirradiation with a maximum association at 48 h. The association is not the result of nonspecific contamination occurring during nuclei purification since nuclei from irradiated cells show no greater levels of plasma membrane marker and mitochondrial marker than controls. The nature of the association remains unclear, but activity is not removed by detergents used in the nuclei isolation procedure, and incubation of the nuclei with EDTA reverses the association only modestly. Exposure of nuclei from irradiated cells to anisotonic buffers also results in only a small decrease in beta-glucuronidase activity associated with the nuclei. These observations suggest that lysosomal hydrolases become intimately associated with the nuclei of irradiated cells.

McClain, D.E.; Kalinich, J.F.; Poplack, J.K.; Snyder, S.L.

1989-02-01

296

Developmental expression of Manduca shade, the P450 mediating the final step in molting hormone synthesis.  

PubMed

The ecdysone 20-monooxygenase (E20MO; 20-hydroxylase) is the enzyme that mediates the conversion of ecdysone (E) to the active insect molting hormone, 20-hydroxyecdysone (20E), which coordinates developmental progression. We report the identification and developmental expression of the Halloween gene shade (shd; CYP314A1) that encodes the E20MO in the tobacco hornworm, Manduca sexta. Manduca Shd (MsShd) mediates the conversion of E to 20E when expressed in Drosophila S2 cells. In accord with the central dogma, the data show that Msshd is expressed mainly in the midgut, Malpighian tubules, fat body and epidermis with very low expression in the prothoracic gland and nervous system. Developmental variations in E20MO enzymatic activity are almost perfectly correlated with comparable changes in the gene expression of Msshd in the fat body and midgut during the fifth instar and the beginning of pupal-adult development. The results indicate three successive and overlapping peaks of expression in the fat body, midgut and Malpighian tubules, respectively, during the fifth larval instar. The data suggest that precise tissue-specific transcriptional regulation controls the levels, and thereby the activity, of the Manduca E20MO. PMID:16473459

Rewitz, Kim F; Rybczynski, Robert; Warren, James T; Gilbert, Lawrence I

2006-02-13

297

CONTROL AND COORDINATION OF VENTILATION AND CIRCULATION IN CRUSTACEANS: RESPONSES TO HYPOXIA AND EXERCISE  

Microsoft Academic Search

SUMMARY The functional morphology, nervous and hormonal control and co- ordination of the cardiovascular and ventilatory systems in decapodan crustaceans is reviewed. Pacemaker function reflects the reliance of crus- taceans on small numbers of large, multipolar neurones. Respiratory gas exchange and transport may be limited by the potential diffusion barrier presented by chitin on the gills and by the relatively

E. W. TAYLOR

1983-01-01

298

DETERMINATION OF LETHAL DISSOLVED OXYGEN LEVELS FOR SELECTED MARINE AND ESTUARINE FISHES, CRUSTACEANS AND A BIVALVE  

EPA Science Inventory

The objective of this study was to provide a database of the incipient lethal concentrations for reduced dissolved oxygen (DO) for selected marine and estuarine species including 12 species of fish, 9 crustaceans, and 1 bivalve. All species occur in the Virginian Province, USA, w...

299

Charles Darwin and Joseph de Bosquet – Brothers in barnacles: How diminutive crustaceans helped shape a theory  

Microsoft Academic Search

Ten years after his return to England on board ‘The Beagle’ in 1836, Charles Robert Darwin (1809–1882) started collecting, dissecting, describing and interpreting both extant and fossil acorn and goose barnacles (cirripedes). In all, he spent eight years on this animal group and, between 1851 and 1855, published four authoritative and admirably illustrated volumes on these sessile crustaceans; a highly

John W. M. Jagt

2011-01-01

300

Molecular Characterization of Crustacean Visual Pigments and the Evolution of Pancrustacean Opsins  

Microsoft Academic Search

Investigations of opsin evolution outside of vertebrate systems have long been focused on insect visual pigments, whereas other groups have received little attention. Furthermore, few studies have explicitly investigated the selective influences across all the currently characterized arthropod opsins. In this study, we contribute to the knowledge of crustacean opsins by sequencing 1 opsin gene each from 6 previously uncharacterized

Megan L. Porter; Thomas W. Cronin; David A. McClellan; Keith A. Crandall

2006-01-01

301

Transglutaminase activity in the hematopoietic tissue of a crustacean, Pacifastacus leniusculus, importance in hemocyte homeostasis  

Microsoft Academic Search

BACKGROUND: Transglutaminases (TGases) form a group of enzymes that have many different substrates and among the most well known are fibrin for Factor XIIIa and the clotting protein in crustaceans. We also found that TGase is an abundant protein in the hematopoietic tissue (Hpt) cells of crayfish and hence we have studied the possible function of this enzyme in hematopoiesis.

Xionghui Lin; Kenneth Söderhäll; Irene Söderhäll

2008-01-01

302

The relative importance of bacteria and algae as food sources for crustacean zooplankton  

Microsoft Academic Search

There is increasing evidence that the main role of the microbial loop in aquatic food webs is rapid remineralization of organic nutrients with little C being transferred to higher trophic levels. There is also evidence, however, that the transfer of C from algae to crustaceans is equally inefficient. This finding suggests that simultaneous determination of C flow from both bacteria

JOHN L. WYLIE; DAVID J. CURRIE

1991-01-01

303

Modulation of Oscillator Interactions in the Crab Stomatogastric Ganglion by Crustacean Cardioactive Peptide  

Microsoft Academic Search

The modulation of the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis, by crustacean cardio- active peptide (CCAP) is described. CCAP activated pyloric rhythms in most silent preparations, and altered the phase relationships of pyloric motor neuron firing in all prepara- tions. In CCAP, the pyloric rhythms were characterized by long lateral pyloric (LP) neuron bursts of

James M. Weimann; Petra Skiebe; Hans-Georg Heinzel; Cristina Soto; Nancy Kopell; Juan Carlos Jorge-Rivera; Eve Marder

1997-01-01

304

Sexual Contests in Aquatic Crustaceans: What's Physiology Got To Do with It?  

ERIC Educational Resources Information Center

|Describes a science laboratory on reproductive behavior and studies the dynamics in Lirceus, an aquatic crustacean of which the females evaluate the males' quality through mating contests. Explains collecting isopods and developing colonies in the lab environment. Investigates food deprivation, locomotor activity, and behavioral trials to…

Keogh, Daniel P.; Sparkes, Timothy C.

2003-01-01

305

Protein synthesis and specific dynamic action in crustaceans: effects of temperature  

Microsoft Academic Search

Temperature influences the specific dynamic action (SDA), or rise in oxygen uptake rate after feeding, in eurythermal and stenothermal crustaceans by changing the timing and the magnitude of the response. Intra-specific studies on the eurythermal crab, Carcinus maenas, show that a reduction in acclimation temperature is associated with a decrease in SDA magnitude, resulting from an increase in SDA duration

N. M. Whiteley; R. F. Robertson; J. Meagor; A. J. El Haj; E. W. Taylor

2001-01-01

306

The effects of temperature on walking and righting in temperate and Antarctic crustaceans  

Microsoft Academic Search

Antarctic marine invertebrates live in a cold, thermally stable environment and cannot tolerate large changes in body temperature (i.e. they are stenothermal). Their temperate relatives, by contrast, are eurythermal, living in warmer and thermally more variable environments. Have these different environments influenced how specific behaviours are affected by changes of temperature? This question was addressed in two temperate crustaceans, the

John S. Young; Lloyd S. Peck; Thomas Matheson

2006-01-01

307

Determination of lethal dissolved oxygen levels for selected marine and estuarine fishes, crustaceans, and a bivalve  

Microsoft Academic Search

The objective of this study was to provide a database of the incipient lethal concentrations for reduced dissolved oxygen (DO) for selected marine and estuarine species including 12 species of fish, 9 crustaceans, and 1 bivalve. All species occur in the Virginian Province, USA, which is a cold temperate region. The study period was August 1987 to September 1995. Standard

D. Miller; S. Poucher; L. Coiro

2002-01-01

308

Skeletal adaptations for forwards and sideways walking in three species of decapod crustaceans  

Microsoft Academic Search

Crustaceans have been successfully employed to study legged locomotion for decades. Most studies have focused on either forwards-walking macrurans, or sideways-walking brachyurans. Libinia emarginata is a Majoid crab (Brachyura) and as such belongs to the earliest group to have evolved the crab form from homoloid ancestors. Unlike most brachyurans, Libinia walks forwards 80% of the time. We employed standard anatomical

A. G. Vidal-Gadea; M. D. Rinehart; J. H. Belanger

2008-01-01

309

Physiological stress in decapod crustaceans ( Munida rugosa and Liocarcinus depurator) discarded in the Clyde Nephrops fishery  

Microsoft Academic Search

Crustacean discards experience stress during commercial fishing operations, due to increased exercise while in the trawl and aerial exposure during sorting of the catch. Physiological stress and recovery were assessed following trawling of two ecologically important decapod species, regularly discarded in the Clyde Nephrops fishery. Haemolymph samples taken from trawled swimming crabs, Liocarcinus depurator, and squat lobsters, Munida rugosa, had

Melanie Bergmann; Alan C Taylor; P Geoffrey Moore

2001-01-01

310

Chemical composition and buoyancy of midwater crustaceans as function of depth of occurrence off Southern California  

Microsoft Academic Search

Water, ash, C, H, N, lipid, carbohydrate, chitin and protein contents were determined for 28 species of midwater crustaceans. Variation of these components as a function of depth of occurrence, relative buouancy and respiratory rate of these species was examined. Vertical distribution data for 10 of the species based on discrete depth crawls is provided. The relative bouyancies of 16

J. J. Childress; M. Nygaard

1974-01-01

311

Immunolocalisation of crustacean-SIFamide in the median brain and eyestalk neuropils of the marbled crayfish.  

PubMed

Crustacean-SIFamide (GYRKPPFNGSIFamide) is a novel neuropeptide that was recently isolated from crayfish nervous tissue. We mapped the localisation of this peptide in the median brain and eyestalk neuropils of the marbled crayfish (Marmorkrebs), a parthenogenetic crustacean. Our experiments showed that crustacean-SIFamide is strongly expressed in all major compartments of the crayfish brain, including all three optic neuropils, the lateral protocerebrum with the hemiellipsoid body, and the medial protocerebrum with the central complex. These findings imply a role of this peptide in visual processing already at the level of the lamina but also at the level of the deeper relay stations. Immunolabelling is particularly strong in the accessory lobes and the deutocerebral olfactory lobes that receive a chemosensory input from the first antennae. Most cells of the olfactory globular tract, a projection neuron pathway that links deuto- and protocerebrum, are labelled. This pathway plays a central role in conveying tactile and olfactory stimuli to the lateral protocerebrum, where this input converges with optic information. Weak labelling is also present in the tritocerebrum that is associated with the mechanosensory second antennae. Taken together, we suggest an important role of crustacean-SIFamidergic neurons in processing high-order, multimodal input in the crayfish brain. PMID:17828557

Polanska, M A; Yasuda, A; Harzsch, S

2007-09-09

312

The role of crustacean fisheries and aquaculture in global food security: past, present and future.  

PubMed

The 1996 World Food Summit defined food security as "Food security exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life". This paper looks at the status of production from both shrimp capture fisheries and shrimp aquaculture, as well as trade, in order to understand the contribution of the crustacean sector to overall fish production and thus to global food security. This paper also examines some sustainability issues that will potentially affect the contribution of the crustacean sector (particularly shrimp) to food security. These include sustainable shrimp capture fisheries, sustainable shrimp trade and sustainable shrimp aquaculture. The paper concludes that crustaceans are an important source of aquatic food protein. Production (as food and ornamental) and trade are extremely important for developing countries. It provides both economic development and empowerment in terms of contribution to GDP, consumption, employment, catch value and exports. The crustacean sector generates high value export products which enables producers to buy lower value products in the world market - thus a positive contribution to food security in both producing and exporting countries. PMID:22433997

Bondad-Reantaso, Melba G; Subasinghe, Rohana P; Josupeit, Helga; Cai, Junning; Zhou, Xiaowei

2012-03-14

313

Distribution patterns of decapod crustaceans in polar areas: a result of magnesium regulation?  

Microsoft Academic Search

Nearly all decapod crustaceans found in Antarctic waters south of the Antarctic Convergence are caridean shrimps (Natantia) while the group of Reptantia is largely absent in this area. Progress in the development of a physiological hypothesis is reported, which explains this distribution pattern based on differences in the regulation of magnesium levels in the haemolymph ([Mg2+]HL) and on the Mg2+

Markus Frederich; Franz Sartoris; Hans-O. Pörtner

2001-01-01

314

Ecological determinants and sensory mechanisms in habitat selection of crustacean postlarvae  

Microsoft Academic Search

Animals use sensory stimuli to assess and select habitats, mates, and food as well as to communicate with other individuals. One of the great mysteries of crustacean ecology is how postlarvae locate the relatively rare patches of coral reef habitat on which they settle. The present study aimed to estimate, by experiments in aquaria and biochemical analysis, the sensory modalities

David Lecchini; Suzanne C. Mills; Christophe Brié; Robert Maurin; Bernard Banaigs

2010-01-01

315

Annotated checklist of decapod crustaceans of Atlantic coastal and continental shelf waters of the United States  

Microsoft Academic Search

The decapod crustacean assemblage inhabiting estuarine, neritic and continental shelf waters (to 190 m) of the temperate eastern United States is diverse, with 391 species reported from Maine to Cape Canaveral, Florida. Three recognized biogeographic provinces (Boreal in part, Virginian and Car­ olinian) are included in this region. The assemblage contains 122 shrimp spe­ cies (28 penaeids, 2 stenopodids, and

Martha S. Nizinski

316

Fish and macro-crustacean communities and their dynamics in the Severn Estuary  

Microsoft Academic Search

The species of fish and macro-crustacean living within the Severn Estuary are reviewed. The fish community is notably species rich and exceeds 100 species in total for the estuary. Standardised long-term sampling at Hinkley Point in Bridgwater Bay gives a total complement of 83 for a single locality and this number is increasing by about one new species every two

P. A. Henderson; D. J. Bird

2010-01-01

317

Insect protein as a partial replacement of fishmeal in the diets of juvenile fish and crustaceans  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter represents a review of the published literature to determine if insect protein is an important supplement to - or even a replacement for - fishmeal in diets for juvenile fish and crustaceans. Fishmeal is becoming a finite resource. This chapter highlights areas of opportunity for produc...

318

Insect Protein as a partial Replacement of Fishmeal in the Diets of Juvenile Fish and Crustaceans  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter represents a review of the published literature to determine if insect protein is an important supplement to - or even a replacement for - fishmeal in diets for juvenile fish and crustaceans. Fishmeal is becoming a finite resource. This chapter highlights areas of opportunity for produc...

319

Subunit compositions of crustacean haemocyanins are species-specific: evidence from non-decapod species  

Microsoft Academic Search

Electrophoretic examination of dissociated haemocyanin subunits from a number of amphipod, decapod and isopod crustaceans supports the hypothesis that subunit composition is species-specific, despite marked within-species variation in many species. General patterns of heterogeneity on native PAGE gels were also evident between groupings within the Amphipoda. Gammarid amphipods could be split into two groups; one characterised by a high degree

Emily Hodgson; John I Spicer

2001-01-01

320

Effects of sewage-impacted sediment on reproduction in the benthic crustacean Leptocheirus plumulosus  

Microsoft Academic Search

Several organic contaminants in sewage effluent have been shown to elicit an estrogenic response in juvenile fish. Comparatively little emphasis has been placed on assessing these effects in marine invertebrates, particularly benthic organisms inhabiting sediment where lipophilic contaminants tend to persist. The present study examined reproductive effects in the benthic crustacean Leptocheirus plumulosus exposed to sewage-impacted sediment from Jamaica Bay,

A. M Zulkosky; P. L Ferguson; A. E McElroy

2002-01-01

321

Insect protein as a partical replacement of fishmeal in the diets of juvenile fish and crustaceans  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter represents a review of the published literature to determine if insect protein is an important supplement to - or even a replacement for - fishmeal in diets for juvenile fish and crustaceans. Fishmeal is becoming a finite resource. This chapter highlights areas of opportunity for prod...

322

Changes in Nucleic Acids over the Molt Cycle in Relation to Food Availability and Temperature in 'Homarus americanus' Postlarvae.  

National Technical Information Service (NTIS)

Postlarval lobsters Homarus americanus, hatched from three females collected in 1989 from Block Island Sound, Rhode Island were reared individually in the laboratory under nine treatment combinations of temperature (15, 18 and 20C) and feeding (starved, l...

M. A. R. Juinio J. S. Cobb D. Bengtson M. Johnson

1992-01-01

323

A comparison of cell killing by heat and/or x rays in Chinese hamster V79 cells, Friend erythroleukemia mouse cells, and human thymocyte MOLT-4 cells  

SciTech Connect

The radiation and/or heat sensitivity of Chinese hamster V79 cells, Friend erythroleukemia (FELC) mouse cells, and MOLT-4 human transformed thymocytes were compared. MOLT-4 cells were more radiosensitive (D/sub o/=0.50 Gy) than FELC (D/sub o/ = 0.65 Gy) and V79 cells (D/sub o/ = 1.43 Gy). Arrhenius analysis showed that MOLT-4 cells were more heat sensitive than FELC or V79 cells below 42.0/sup 0/C, but more heat resistant at higher temperatures. In addition, the MOLT-4 cells showed a single-heat inactivation energy between 41.0 and 45.0/sup 0/C, while FELC and V79 cells both showed a transition in the inactivation energy at about 43.0 and 43.5/sup 0/C, respectively. These differences may be related to the fact that the upper temperature limit for the development of thermal tolerance during continuous heating was lower for MOLT-4 cells than for FELC or V79 cells. Killing of FELC and V79 cells was dependent on the sequence in which heat and X rays were applied, but the greatest effect was obtained when both treatments were given simultaneously. Recovery occurred when treatments were separated by incubation at 37.0/sup 0/C. The MOLT-4 cells did not show a sequence dependence for heating and irradiation. Survival of MOLT-4 cells after heating and/or irradiation was compared using trypan blue dye exclusion or colony formation. Both assays showed similar qualitative responses, but survival levels measured by the trypan blue assay were much higher than those determined from the colony-forming assay.

Raaphorst, G.P.; Szekely, J.; Lobreau, A.; Azzam, E.I.

1983-05-01

324

The Salmon Louse Lepeophtheirus salmonis (Copepoda: Caligidae) Life Cycle Has Only Two Chalimus Stages.  

PubMed

Each year the salmon louse (Lepeophtheirussalmonis Krøyer, 1838) causes multi-million dollar commercial losses to the salmon farming industry world-wide, and strict lice control regimes have been put in place to reduce the release of salmon louse larvae from aquaculture facilities into the environment. For half a century, the Lepeophtheirus life cycle has been regarded as the only copepod life cycle including 8 post-nauplius instars as confirmed in four different species, including L. salmonis. Here we prove that the accepted life cycle of the salmon louse is wrong. By observations of chalimus larvae molting in incubators and by morphometric cluster analysis, we show that there are only two chalimus instars: chalimus 1 (comprising the former chalimus I and II stages which are not separated by a molt) and chalimus 2 (the former chalimus III and IV stages which are not separated by a molt). Consequently the salmon louse life cycle has only six post-nauplius instars, as in other genera of caligid sea lice and copepods in general. These findings are of fundamental importance in experimental studies as well as for interpretation of salmon louse biology and for control and management of this economically important parasite. PMID:24069203

Hamre, Lars A; Eichner, Christiane; Caipang, Christopher Marlowe A; Dalvin, Sussie T; Bron, James E; Nilsen, Frank; Boxshall, Geoff; Skern-Mauritzen, Rasmus

2013-09-12

325

The Salmon Louse Lepeophtheirus salmonis (Copepoda: Caligidae) Life Cycle Has Only Two Chalimus Stages  

PubMed Central

Each year the salmon louse (Lepeophtheirussalmonis Krøyer, 1838) causes multi-million dollar commercial losses to the salmon farming industry world-wide, and strict lice control regimes have been put in place to reduce the release of salmon louse larvae from aquaculture facilities into the environment. For half a century, the Lepeophtheirus life cycle has been regarded as the only copepod life cycle including 8 post-nauplius instars as confirmed in four different species, including L. salmonis. Here we prove that the accepted life cycle of the salmon louse is wrong. By observations of chalimus larvae molting in incubators and by morphometric cluster analysis, we show that there are only two chalimus instars: chalimus 1 (comprising the former chalimus I and II stages which are not separated by a molt) and chalimus 2 (the former chalimus III and IV stages which are not separated by a molt). Consequently the salmon louse life cycle has only six post-nauplius instars, as in other genera of caligid sea lice and copepods in general. These findings are of fundamental importance in experimental studies as well as for interpretation of salmon louse biology and for control and management of this economically important parasite.

Dalvin, Sussie T.; Bron, James E.; Nilsen, Frank; Boxshall, Geoff; Skern-Mauritzen, Rasmus

2013-01-01

326

The nymphal-adult molt of the silverleaf whitefly (Bemisia argentifolii): Timing, regulation, and progress.  

PubMed

The developmental progress of silverleaf whitefly (Bemisia argentifolii) 3rd instars and 4th instar/pharate adults was monitored using a tracking system that had been designed to identify synchronous individuals in another species of whitefly, the greenhouse whitefly, Trialeurodes vaporariorum. When reared on greenbean under conditions of LD 16:8 and a temperature of 26 +/- 2 degrees C, the body depth of 3rd instar SLWFs increased from approximately 0.04 mm (Stage 2) to 0.175-0.2 mm (Stage 7-8) and the body depth of the 4th instar increased from approximately 0.1 mm (Stage 1) to 0.25-0.30 mm (Stage 4-5). The durations of the 3rd instar and the 4th instar/pharate adult were approximately 3 and 7 days, respectively. Examination of coronal sections of 4th instars revealed that adult eye and wing development are initiated during Stage 6, the stage in which an external examination showed that the eye has begun to undergo pigment diffusion. Ecdysteroid titers peaked at approximately 400 fg/ micro g protein during stages 4 through 6A of the 4th instar, i.e., just prior to and upon the initiation of the pharate adult stage. Although adult development is initiated later in the SLWF than in the GHWF (adult eye and wing development begin in Stages 4 and 5, respectively, in GHWFs), the same rapidity of metamorphosis is observed in both species. Within approximately 24 h, the simple bi-layered wing bud developed into a deeply folded wing of nearly adult proportions and within an additional 12-24 h, the nymphal eye and wing bud had been replaced by the well-differentiated eye and wing of the adult whitefly. Our study is the first to describe the regulation, timing, and progress of the nymphal-adult molt and of the structural changes that accompany nymphal-adult metamorphosis in the SLWF. PMID:12232874

Gelman, Dale B; Blackburn, Michael B; Hu, Jing S; Gerling, Dan

2002-10-01

327

Amino acids and TOR signaling promote prothoracic gland growth and the initiation of larval molts in the tobacco hornworm Manduca sexta.  

PubMed

Molting in arthropods is orchestrated by a series of endocrine changes that occur towards the end of an instar. However, little is understood about the mechanisms that trigger these endocrine changes. Here, nutritional inputs were manipulated to investigate the minimal nutritional inputs required for a Manduca sexta larva to initiate a molt. Amino acids were found to be necessary for a larva to molt, indicating the involvement of an amino acid sensitive pathway. Feeding rapamycin, an inhibitor of the target of rapamycin (TOR) signaling, delayed the onset of a molt and resulted in abnormally larger larvae. Rapamycin also suppressed the growth of the prothoracic glands relative to the whole body growth, and this was accompanied by suppression of ecdysone production and secretion. Higher doses of rapamycin also slowed the growth rate, indicating that TOR signaling also plays a role in systemic growth. TOR signaling therefore couples the nutritional status of the larva to the endocrine system to regulate the timing of a molt. PMID:22984508

Kemirembe, Karen; Liebmann, Kate; Bootes, Abigail; Smith, Wendy A; Suzuki, Yuichiro

2012-09-12

328

Sampling Daphnia's expressed genes: preservation, expansion and invention of crustacean genes with reference to insect genomes  

PubMed Central

Background Functional and comparative studies of insect genomes have shed light on the complement of genes, which in part, account for shared morphologies, developmental programs and life-histories. Contrasting the gene inventories of insects to those of the nematodes provides insight into the genomic changes responsible for their diversification. However, nematodes have weak relationships to insects, as each belongs to separate animal phyla. A better outgroup to distinguish lineage specific novelties would include other members of Arthropoda. For example, crustaceans are close allies to the insects (together forming Pancrustacea) and their fascinating aquatic lifestyle provides an important comparison for understanding the genetic basis of adaptations to life on land versus life in water. Results This study reports on the first characterization of cDNA libraries and sequences for the model crustacean Daphnia pulex. We analyzed 1,546 ESTs of which 1,414 represent approximately 787 nuclear genes, by measuring their sequence similarities with insect and nematode proteomes. The provisional annotation of genes is supported by expression data from microarray studies described in companion papers. Loci expected to be shared between crustaceans and insects because of their mutual biological features are identified, including genes for reproduction, regulation and cellular processes. We identify genes that are likely derived within Pancrustacea or lost within the nematodes. Moreover, lineage specific gene family expansions are identified, which suggest certain biological demands associated with their ecological setting. In particular, up to seven distinct ferritin loci are found in Daphnia compared to three in most insects. Finally, a substantial fraction of the sampled gene transcripts shares no sequence similarity with those from other arthropods. Genes functioning during development and reproduction are comparatively well conserved between crustaceans and insects. By contrast, genes that were responsive to environmental conditions (metal stress) and not sex-biased included the greatest proportion of genes with no matches to insect proteomes. Conclusion This study along with associated microarray experiments are the initial steps in a coordinated effort by the Daphnia Genomics Consortium to build the necessary genomic platform needed to discover genes that account for the phenotypic diversity within the genus and to gain new insights into crustacean biology. This effort will soon include the first crustacean genome sequence.

Colbourne, John K; Eads, Brian D; Shaw, Joseph; Bohuski, Elizabeth; Bauer, Darren J; Andrews, Justen

2007-01-01

329

Identification and cloning of a selenophosphate synthetase (SPS) from tiger shrimp, Penaeus monodon, and its transcription in relation to molt stages and following pathogen infection.  

PubMed

Complementary (c)DNA encoding selenophosphate synthetase (SPS) messenger (m)RNA of the tiger shrimp Penaeus monodon, designated PmSPS, was obtained from the hepatopancreas by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The 1582-bp cDNA contained an open reading frame (ORF) of 1248 bp, a 103-bp 5'-untranslated region (UTR), and a 231-bp 3'-UTR, which contained a conserved selenocysteine insertion sequence (SECIS) element, a conventional polyadenylation signal, and a poly A tail. The molecular mass of the deduced amino acid (aa) sequence (416 aa) was 45.5 kDa with an estimated pI of 4.85. It contained a putative selenocysteine residue which was encoded by the unusual stop codon, (275)TGA(277), which formed at the active site with residues Sec(58) and Lys(61). A comparison of amino acid sequences showed that PmSPS was more closely related to invertebrate SPS1, such as those of Heliothis virescens and Drosophila melanogaster a and b. PmSPS cDNA was synthesized in all tested tissues, especially in the hepatopancreas. PmSPS in the hepatopancreas of shrimp significantly increased after an injection with either Photobacterium damsela or white spot syndrome virus (WSSV) in order to protect cells against damage from oxidation, and enhance the recycling of selenocysteine or selenium metabolism, indicating that PmSPS is involved in the disease-resistance response. The PmSPS expression by hemocytes significantly increased in stage C, and then gradually decreased until stage A, suggesting that the cloned PmSPS in hemocytes might play a role in viability by renewing hemocytes and antioxidative stress response for new exoskeleton synthesis during the molt cycle of shrimp. PMID:21664929

Yeh, Maw-Sheng; Huang, Chang-Jen; Guo, Chih-Hung; Liu, Kuan-Fu; Tsai, Inn-Ho; Cheng, Winton

2011-06-12

330

Metabolic rates and energy content of deep-sea benthic decapod crustaceans in the western Mediterranean Sea  

Microsoft Academic Search

A total of 23 species of deep-sea benthic decapod crustaceans were collected in the Catalan Sea (western Mediterranean) at different depths (200–1250m) but at the same environmental temperature (13°C) in winter 1992 and winter 1993. Studies on oxygen consumption and energy content were carried out on crustaceans exhibiting two life strategies: nektobenthic species (benthic species with a slight locomotory ability)

F. Sarda

1998-01-01

331

Comparative distribution of a putative egg-laying hormone in neural and reproductive tissues of four Decapoda crustaceans  

Microsoft Academic Search

Evidence for the presence of a putative egg-laying (ELH) hormone has been previously described in the black tiger shrimp,\\u000a Penaeus monodon, so a further investigation was carried out to detect its presence in a range of Decapoda crustaceans prior to a full molecular\\u000a analysis. The crustaceans were represented by the Australian fresh water yabbie, Cherax destructor, the Australian southern rock

Zhipeng Liu; John Donald; Peter Hanna; Parinyaphon Nuurai; Prasert Sobhon

2009-01-01

332

Metabolismof l-ß-D-Arabinofuranosyl-5-azacytosme and Incorporationinto DMAof HumanT-LymphoblasticCells (Molt4)1  

Microsoft Academic Search

ß-D-Arabinofuranosyl-5-azacytosine(ara-5-aza-Cyd) had po tent cytotoxicity against human T-type lymphoblastic cells in culture. When Molt-4 cells were exposed to ara-5-aza-Cyd for 24 h, clonogenic survival was reduced by 50 and 98% at initial concentrations of 10~7and 10~6M, respectively, compared to 3 x 10~8and 10~6M, respectively, for the same effect with 1-\\/3-D- arabinofuranosylcytosine (ara-C). The analogue is chemically unstable, with a iv2

Alan Townsend; Jean-Marie Ledere; Ginger Dutschman; David Cooney; Yung-chi Cheng

333

Assemblages of peracarid crustaceans in subtidal sediments from the Ría de Aldán (Galicia, NW Spain)  

NASA Astrophysics Data System (ADS)

Peracarid crustaceans inhabit many marine benthic habitats and are good indicators of environmental conditions. There is, however, a lack of information about diversity and distribution of peracarid crustaceans on the shallow subtidal sediments of the Galician rias. In the summer of 1997, 27 subtidal stations were sampled in the Ría de Aldán, a ria on the southern margin of the mouth of the Ría de Pontevedra (Galicia, NW Spain). A total of 16,191 peracarid individuals were collected, comprising 125 species belonging to five orders. Amphipods were dominant in number of species and individuals, followed by isopods and cumaceans. Multivariate analyses of these data indicated that depth and sediment granulometry were major determinants of distribution and composition of peracarid assemblages in the ria.

Lourido, Antía; Moreira, Juan; Troncoso, Jesús S.

2008-12-01

334

Crustacean assemblages in a polluted estuary from South-Western Spain.  

PubMed

The spatial-temporal variation in crustacean assemblages of the Odiel-Tinto estuary, one of the most polluted areas in the world, was studied in 2000, 2002 and 2004. The crustacean assemblages were mainly established according to the natural gradient from estuarine to marine environment (based on water and sediment characteristics such as dissolved oxygen, salinity, granulometry or organic content). Pollutants such as copper, zinc or phosphates could also explain partially this pattern based on BIOENV and canonical correspondence analyses. However, there were clear symptoms of perturbation, mainly in the inner areas, such as a low number of species and a low abundance, especially in relation to the typical estuarine species (e.g. Cyathura carinata, Corophium spp.). This study provides baseline information which can be used as a reference point in a long-term perspective. PMID:20701928

Sánchez-Moyano, J Emilio; García-Asencio, Isabel

2010-08-10

335

Effects of temperature and salinity on the development of the amphipod crustacean Eogammarus sinensis  

NASA Astrophysics Data System (ADS)

The amphipod crustacean Eogammarus sinensis has useful features that make it suitable for use in the aquaculture of fish and large decapod crustaceans. In this study, we investigated the effects of temperature and salinity on the development, fecundity, survival, and growth rate of E. sinensis. The results show that temperature significantly affected E. sinensis development, but salinity. As temperature increased, the duration of E. sinensis embryonic development decreased. Fecundity was affected significantly by temperature and the combination of temperature and salinity, but by salinity alone. In addition, high temperatures accelerated E. sinensis juvenile growth rates, whereas high salinity reduced it. Therefore, our data suggest that E. sinensis tolerates a wide range of salinities and that temperature has more significant effects than salinity on the embryonic development, fecundity, and growth of E. sinensis. Our results shall be useful for mass production of this species for use in aquaculture.

Xue, Suyan; Fang, Jianguang; Zhang, Jihong; Jiang, Zengjie; Mao, Yuze; Zhao, Fazhen

2013-09-01

336

Selfing in a malacostracan crustacean: why a tanaidacean but not decapods  

NASA Astrophysics Data System (ADS)

The crustacean class Malacostraca, with over 22,000 species, includes commercially important members, such as crabs, shrimps, and lobsters. A few simultaneous hermaphrodites are known in this group, but self-fertilization was unknown. Here we show, through microscopy and breeding experiments, that the simultaneously hermaphroditic malacostracan Apseudes sp. (order Tanaidacea) can self-fertilize; individuals reared in isolation become hermaphroditic via a male-like phase and produce eggs that develop into fertile adults. Although selfing occurs in crustaceans like the Branchiopoda, in which simultaneous hermaphrodites have the sex ducts united, in decapods the separation of gonadal ducts and gonopores, specialized mating organs, and complex mating behavior appear to have constrained the evolution of selfing. In contrast, in most tanaidaceans, sperm is released externally by a male and reaches the eggs in the female brood pouch, where fertilization occurs. This mode of fertilization permitted Apseudes sp. to achieve selfing without large modifications in morphology or behavior.

Kakui, Keiichi; Hiruta, Chizue

2013-09-01

337

Crustaceans from bitumen clast in Carboniferous glacial diamictite extend fossil record of copepods.  

PubMed

Copepod crustaceans are extremely abundant but, because of their small size and fragility, they fossilize poorly. Their fossil record consists of one Cretaceous (c. 115?Ma) parasite and a few Miocene (c. 14?Ma) fossils. In this paper, we describe abundant crustacean fragments, including copepods, from a single bitumen clast in a glacial diamictite of late Carboniferous age (c. 303?Ma) from eastern Oman. Geochemistry identifies the source of the bitumen as an oilfield some 100-300?km to the southwest, which is consistent with an ice flow direction from glacial striae. The bitumen likely originated as an oil seep into a subglacial lake. This find extends the fossil record of copepods by some 188?Ma, and of free-living forms by 289?Ma. The copepods include evidence of the extant family Canthocamptidae, believed to have colonized fresh water in Pangaea during Carboniferous times. PMID:20975721

Selden, Paul A; Huys, Rony; Stephenson, Michael H; Heward, Alan P; Taylor, Paul N

2010-08-10

338

Purinergic olfactory cells of crustaceans: response characteristics and similarities to internal purinergic cells of vertebrates  

Microsoft Academic Search

1.Purinergic cells, stimulated by adenosine and adenine nucleotides, are found internally in the brain, heart, and other organs of vertebrates. The olfactory systems of two marine crustaceans also possess purinergic receptors that exhibit response specificities and antagonistic effects similar to a type of vertebrate purinoceptor.2.Electrophysiological recordings from single olfactory cells in the antennules of the spiny lobsterPanulirus argus (this study),

Charles D. Derby; William E. S. Carr; Barry W. Ache

1984-01-01

339

N -glycan moieties of the crustacean egg yolk protein and their glycosylation sites  

Microsoft Academic Search

Vitellogenin (Vg) is the precursor of the egg yolk glycoprotein of crustaceans. In the prawn Macrobrachium rosenbergii, Vg is synthesized in the hepatopancreas, secreted to the hemolymph, and taken up by means of receptor-mediated endocytosis\\u000a into the oocytes. The importance of glycosylation of Vg lies in its putative role in the folding, processing and transport\\u000a of this protein to the

Ziv Roth; Shmuel Parnes; Simy Wiel; Amir Sagi; Nili Zmora; J. Sook Chung; Isam Khalaila

2010-01-01

340

Long-term fish and macro-crustacean community variation in a Mediterranean lagoon  

Microsoft Academic Search

The fish and macro-crustacean community of the Vaccarès lagoon (Rhône River delta, South France) was sampled monthly from 1993 to 2002. The lagoon salinity shifted from 15 in 1993 to 5 in 1994–1997 and went back to 15 in 1999–2002. Connections with the sea also varied during the study period with larger openings in 1996–1997. During the study period, the

Gilles Poizat; Elizabeth Rosecchi; Philippe Chauvelon; Pascal Contournet; Alain J Crivelli

2004-01-01

341

Development of an RNA interference method in the cladoceran crustacean Daphnia magna  

Microsoft Academic Search

Daphnids are small crustaceans ubiquitous in fresh water; they have been a subject of study in ecology, evolution, and environmental\\u000a sciences for decades. To understand data accumulated in daphnid biology at the molecular level, expressed sequence tags and\\u000a a genome sequence have been determined. However, these discoveries lead to the problem of how to understand the functions\\u000a of newly discovered

Yasuhiko Kato; Yasuhiro Shiga; Kaoru Kobayashi; Shin-ichi Tokishita; Hideo Yamagata; Taisen Iguchi; Hajime Watanabe

2011-01-01

342

Evolution of Hox3 and ftz in arthropods: insights from the crustacean Daphnia pulex  

Microsoft Academic Search

The Drosophila melanogaster genes zerknüllt (zen) and fushi tarazu (ftz) are members of the Hox gene family whose roles have changed significantly in the insect lineage and thus provide an opportunity to study the mechanisms\\u000a underlying the functional evolution of Hox proteins. We have studied the expression of orthologs of zen (DpuHox3) and ftz (Dpuftz) in the crustacean Daphnia pulex

Daniel Papillon; Maximilian J. Telford

2007-01-01

343

Effects of Pollutants on Olfactory Mediated Behaviors in Fish and Crustaceans  

Microsoft Academic Search

\\u000a Streams, lakes and the sea are the final sinks of various pollutants which means that aquatic organisms are exposed to many\\u000a different chemicals present in the ambient water. Several studies demonstrate that these pollutants may interfere with chemoreception\\u000a of aquatic animals. Many aquatic vertebrates and invertebrates depend on chemical senses for their survival and reproduction.\\u000a In fish and crustaceans, olfactory

K. Håkan Olsén

344

Megabenthic decapod crustacean assemblages on the Galician continental shelf and upper slope (north-west Spain)  

Microsoft Academic Search

The structure of megabenthic decapod crustacean assemblages on the Galician (north-west Spain) continental shelf (100 to\\u000a 200 depth) and upper slope (200 to 500 m) was analyzed based on surveys carried out in autumn and spring, from 1980 to 1987.\\u000a Forty species belonging to 19 families were caught. The portunid crab Polybius henslowii, a species with pelagic phases, was the

A. C. Fariña; J. Freire; E. González-Gurriarán

1997-01-01

345

Accumulation of aluminium by the freshwater crustacean Asellus aquaticus in neutral water  

Microsoft Academic Search

This study examined the accumulation of aluminium (Al), mostly as the insoluble (Al(OH)3) species, by the freshwater crustacean Asellus aquaticus at neutral pH. Animals were exposed to a range of Al concentrations (5–356 ?g l?1) in three experiments. The first two were of 30 and 50 days duration, respectively, followed by transfer of the A. aquaticus to water containing no

R Elangovan; S Ballance; K. N White; C. R McCrohan; J. J Powell

1999-01-01

346

Cool-sensitive Neurons in the Ventral Nerve Cord of Crustaceans  

Microsoft Academic Search

The firing properties and distribution of the cool-sensitive neurons in the ventral nerve cord were studied in four crustacean species (Panulirus japonicus, Penaeus japonicus, Homarus americanus and Ligia exotica). Several efferent axons in each of the three nerve roots (r1, r2, r3) initiated impulses or raised frequency of spontaneous impulses when the isolated nerve cord was cooled for 3–5 min.

Masaki Tani; Taketeru Kuramoto

1998-01-01

347

Reef-associated crustacean fauna: biodiversity estimates using semi-quantitative sampling and DNA barcoding  

Microsoft Academic Search

The cryptofauna associated with coral reefs accounts for a major part of the biodiversity in these ecosystems but has been\\u000a largely overlooked in biodiversity estimates because the organisms are hard to collect and identify. We combine a semi-quantitative\\u000a sampling design and a DNA barcoding approach to provide metrics for the diversity of reef-associated crustacean. Twenty-two\\u000a similar-sized dead heads of Pocillopora

L. Plaisance; N. Knowlton; G. Paulay; C. Meyer

2009-01-01

348

Biological monitoring of fish and crustaceans in the Wadden Sea — potential and problems  

Microsoft Academic Search

Monitoring of fish and crustaceans in the Wadden Sea (WS) must cope with rapid changes in distribution patterns, access to\\u000a certain areas and gear efficiency. Application and limitations of a variety of fishing devices (fyke nets, gill nets, enclosures,\\u000a stow nets, purse seines, beam trawls, push nets, beach seines, bottom trawls, pelagic trawls) are discussed with regard to\\u000a different objectives

Maarten Ruth; Rüdiger Berghahn

1989-01-01

349

THE EFFECT OF PRE- AND POSTMOLT DIETS HIGH IN OMEGA-3 FATTY ACIDS AND MOLT PROGRAMS ON SKELETAL INTEGRITY AND INSULIN-LIKE GROWTH FACTOR-I OF WHITE LEGHORNS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study investigated changes in bone integrity and circulating levels of insulin-like growth factor I (IGF-I) of hens subjected to two distinct molting regimens and fed pre- and post molt diets either high or low in omega-3 fatty acids (FA). A dual energy X-ray absorptiometer determined bone mine...

350

The Environmental-Endocrine Basis of Gynandromorphism (Intersex) in a Crustacean  

PubMed Central

Commensurate with the decline in many crustacean populations has been an accumulation in reports of sexually ambiguous individuals within these populations. The cause of gynandromorphism or intersex among crustaceans is unknown. We show that gynandromorphism in the branchiopod crustacean Daphnia magna is initiated by the sex-determining hormone methyl farnesoate when levels of the hormone are intermediate between low levels that stimulate the production of broods containing all female offspring and high levels that stimulate the production of broods of all male offspring. The incidence of hormonally-induced gynandromorphism was low (0.14% at the maximum stimulatory hormone concentrations) but was significantly increased (46-fold) when the animals were hormone-treated at 30oC. Some environmental chemicals also can stimulate the gynandromorphic phenotype as we demonstrated with the insecticide pyriproxyfen. Gynandromorphism occurs due to inadequate signaling of male-sex determination since: a) gynandromorphs did not occur in a population that was producing only female offspring; and, b) conditions that stimulated gynandromorphism also reduced the incidence of male offspring. We suggest that male sex determination normally occurs prior to the first embryonic cleavage. Elevated temperature may alter the timing of sex determination such that methyl farnesoate signaling occurs after the first embryonic cleavage and bilateral gynandromorphism occurs as a consequence of signaling to only one of the daughter cells. These results demonstrate that environmental factors can cause aberrant sex determination via perturbations in methyl farnesoate signaling.

Olmstead, Allen W.; LeBlanc, Gerald A.

2007-01-01

351

Metal toxicity, uptake and bioaccumulation in aquatic invertebrates--modelling zinc in crustaceans.  

PubMed

We use published data on the different patterns of the bioaccumulation of zinc by three crustaceans, the caridean decapod Palaemon elegans, the amphipod Orchestia gammarellus and the barnacle Amphibalanus amphitrite, to construct comparative biodynamic models of the bioaccumulation of zinc into metabolically available and detoxified components of accumulated zinc in each crustacean under both field and laboratory toxicity test conditions. We then link these bioaccumulation models to the onset of toxic effects on exposure of the crustaceans to high dissolved zinc bioavailabilities, using the tenets that toxicity effects are related to the total uptake rate of the toxic metal, and that toxicity is not usually dependent on the total accumulated metal concentration but always on the concentration of accumulated metal that is metabolically available. We dismiss the general concept that there is a critical accumulated body concentration of a metal in an invertebrate at which toxicity ensues, except under specific circumstances involving a rare lack of storage detoxification of accumulated metal. We thus propose a theoretical framework that can be extended to other metals and other aquatic invertebrates (indeed other animals) to explain the variation in the relationship between bioaccumulated body concentrations and toxicity, and subsequently to predict this relationship in many other species for which we have bioaccumulation modelling data. PMID:21872557

Rainbow, P S; Luoma, S N

2011-08-09

352

Timing and ecdysteroid regulation of the molt in last instar greenhouse whiteflies (Trialeurodes vaporariorum).  

PubMed

A system of markers has been devised to track the development of 3rd and 4th instar/pharate adult greenhouse whiteflies. Instars were identified based on measurements of body width and body length. Depending upon the host plant, the product of the two measurements was exceptionally useful in distinguishing between instars. Body depth was used to divide the 3rd instar into eight stages and body depth and color and appearance of the developing adult eye were used to divide the 4th instar/pharate adult into nine stages. Under conditions of L:D 16:8 and a temperature of 26+/-2 degrees C, the body depth of 3rd instars reared on greenbean increased from 0.025 (stage 1) to 0.2mm (stage 8) and the instar duration was approximately 3 days. The body depth of 4th instars increased from approximately 0.1+/-0.02 (Stage 1) to 0.3+/-0.03mm (Stage 5) and then remained constant or decreased slightly during adult development. Ecdysteroid titers peaked at approximately 120fg/&mgr;g protein during Stages 3 through 6 of the 4th instar. Based on an external examination of developing 4th instars and the fluctuations in ecdysteroid titer, it appears that adult development is initiated in Stage 4 or 5 4th instars. Results from histological studies support this view. In Stage 4 nymphs, a subtle change was observed in the corneagenous cells of the eye. However, most Stage 4 4th instars possessed wing development characteristic of earlier, immature stages. In all Stage 5 insects, wing development had been initiated and the corneagenous cells had become quite distinct. In Stage 6 whiteflies, the wing buds were deeply folded and by Stage 7, spines were observed on the new cuticle, indicating that the adult cuticle was well-formed by this stage. Our study is the first to investigate the timing and regulation of the molt, to monitor ecdysteroid titers in precisely staged 4th instar whiteflies and to examine the internal anatomical changes associated with metamorphosis in these tiny homopteran insects. PMID:12770133

Gelman, D B.; Blackburn, M B.; Hu, J S.

2002-01-01

353

Asparagine synthetase expression alone is sufficient to induce l-asparaginase resistance in MOLT-4 human leukaemia cells.  

PubMed

Childhood acute lymphoblastic leukaemia (ALL) is treated by combination chemotherapy with a number of drugs, always including the enzyme L-asparaginase (ASNase). Although the initial remission rate is quite high, relapse and associated drug resistance are a significant problem. In vitro studies have demonstrated increased asparagine synthetase (AS) expression in ASNase-resistant cells, which has led to the hypothesis that elevated AS activity permits drug-resistant survival. The data presented show that not only is elevated AS expression a property of ASNase-resistant MOLT-4 human leukaemia cells, but that short-term (12 h) treatment of the cells with ASNase causes a relatively rapid induction of AS expression. The results also document that the elevated expression of AS in ASNase-resistant cells is not fully reversible, even 6 weeks after ASNase removal from the culture medium. Furthermore, ASNase resistance, assessed as both drug-insensitive cell growth rates and decreased drug-induced apoptosis, parallels this irreversible AS expression. Mimicking the elevated AS activity in ASNase-resistant cells by overexpression of the human AS protein by stable retroviral transformation of parental MOLT4 cells is sufficient to induce the ASNase-resistance phenotype. These data document that ASNase resistance in ALL cells is a consequence of elevated AS expression and that although other drug-induced metabolic changes occur, they are secondary to the increased asparagine biosynthetic rate. PMID:11415466

Aslanian, A M; Fletcher, B S; Kilberg, M S

2001-07-01

354

Interactions between behaviour and physical forcing in the control of horizontal transport of decapod crustacean larvae.  

PubMed

We summarize what is known of the biophysical interactions that control vertical migration and dispersal of decapod larvae, asking the following main questions: How common is vertical migration in decapod crustacean larvae? What is the vertical extent of the migrations? What are the behavioural mechanisms that control vertical migrations? How does vertical migration interact with the physics of the ocean to control the dispersal of larvae? These questions are analysed by first giving a synopsis of the physical processes that are believed to significantly affect horizontal transport, and then by describing migration patterns according to taxon, to ecological category based on the habitat of adults and larvae, and to stage within the larval series. Some kind of vertical migration has been found in larval stages of virtually all species that have been investigated, irrespective of taxonomic or ecological category. Most vertical migration schedules have a cyclic nature that is related to a major environmental cyclic factor. Tidal (ebb or flood) migration and daily (nocturnal and twilight) migration are the two types of cyclic migration that have been identified. In general, all species show some type of daily migration, with nocturnal migration being the most common, whereas tidal migrations have only been identified in species that use estuaries during part of their life cycle. Moreover, there are several examples indicating that the phasing and extent of migration both change throughout ontogeny. Reported ranges of vertical displacement vary between a few metres in estuaries and several tens of metres (sometimes more than 100 m) in shelf and oceanic waters. Vertical movements are controlled by behavioural responses to the main factors of the marine environment. The most important factors in this respect are light, pressure and gravity, but salinity, temperature, turbulence, current and other factors, also influence behaviour. Many of these factors change cyclically, and the larvae respond with cyclic behaviours. The type of response may be endogenous and regulated by an internal clock, as in the case of some tidally synchronised migrations, but in most cases it is a direct response to a change in an environmental variable, as in diel migration. The reaction of the larvae to exogenous cues depends both on the rate of change of the variable and on the absolute amount of change. A series of dispersal types, involving different spatial and temporal scales, have been identified in decapod larvae: retention of the larval series within estuaries; export from estuarine habitats, dispersal over the shelf, and reinvasion of estuaries by the last stage; hatching in shelf waters and immigration to estuaries by late larvae or postlarvae; complete development on the shelf; and hatching in shelf waters, long-range dispersal in the ocean, and return to the shelf by late stages. In all of these cases, vertical migration behaviour and changes of behaviour during the course of larval development have been related to particular physical processes, resulting in conceptual mechanisms that explain dispersal and recruitment. Most decapod larvae are capable of crossing the vertical temperature differences normally found across thermoclines in natural systems. This ability may have significant consequences for horizontal transport within shelf waters, because amplitude and phase differences of the tidal currents across the thermocline may be reflected in different trajectories of the migrating larvae. PMID:15596167

Queiroga, Henrique; Blanton, Jack

2005-01-01

355

Survivorship in micro fungi and crustacean resting stages during ultraviolet (UV) and vacuum land testing of EXPOSE unit  

NASA Astrophysics Data System (ADS)

Dormancy protects animals and plants in harsh environmental conditions within a special resting phases of life cycle lasting from months up to hundred years. This phenomenon is perspective for space researches on interplanetary quarantine within space missions. Direct experiments in open space supported in principle the fact of survivorship of bacteria and fungi spores in open space during long time experiments (Novikova et al. 2007). The rate of survivorship in long-term mission was low but enough to conclude that biological invasion to Mars is a real danger. The possibility for resting stages to survive under UV treatment in vacuum without some protection was not clear. To test it dormant stages (spores) of primitive fungi Aspergillus versicolor, Aspergillus sydowii, Penicillium expansum, and Penicillium aurantiogriseum derived from ISS environment were used in the land EXPOSE imitation of outside space station UV and vacuum conditions. Survivorship in resting eggs of some crustaceans with dried (cladoceran Daphnia magna, fair-shrimp Streptocephalus torvicornis and ostracode Eucypris ornate from hemi desert Caspian area) and wet diapause state (copepod Mixodiaptomus tatricus from the Tatra mountains, altitude 1510 m) was tested also. The total UV dose of 9,1x10 to the 4th KJ/m2 during this imitation was accomplished with a SOL 2000 sun simulator lamp. The final vacuum value achieved during EST was 10 to the minus 6 Pa. Temperature during the experiment fluctuated in the range 19-25 o C. Micro fungi showed a high level of survivorship in samples treated with UV samples varied from 95 till 100 Supported by RFBR grant 07-04-00006.

Alekseev, Victor; Alekseev, Victor; Novikova, Nataliya; Sychev, Vladimir; Levinskikh, Margarita; Deshevaya, Elena; Brancelj, Anton; Malyavin, Stanislav

356

A new rearranged cholestane glycoside from ornithogalum saundersiae bulbs exhibiting potent cytostatic activities on leukemia HL60 and molt-4 cells  

Microsoft Academic Search

A new rearranged cholestane glycoside (1) was isolated from Ornithogalum saundersiae bulbs by monitoring the cytostatic activity on leukemia HL-60 cells. Compound 1 was exceptionally cytostatic against HL-60 and MOLT-4 cells, which was revealed to be mediated partially through induction of apoptosis.

Kazuo Koike; Tamotsu Nikaido

1996-01-01

357

Abundance of ringed seals (Pusa hispida) in the fjords of Spitsbergen, Svalbard, during the peak molting period  

USGS Publications Warehouse

Ringed seal (Pusa hispida) abundance in Spitsbergen, Svalbard, was estimated during the peak molting period via aerial, digital photographic surveys. A total of 9,145 images, covering 41.7%?100% of the total fast-ice cover (1,496 km2) of 18 different fjords and bays, were inspected for the presence of ringed seals. A total of 1,708 seals were counted, and when accounting for ice areas that were not covered by images, a total of 3,254 (95% CI: 3,071?3,449) ringed seals were estimated to be hauled out during the surveys. Extensive behavioral data from radio-tagged ringed seals (collected in a companion study) from one of the highest density fjords during the molting period were used to create a model that predicts the proportion of seals hauled out on any given date, time of day, and under various meteorological conditions. Applying this model to the count data from each fjord, we estimated that a total of 7,585 (95% CI: 6,332-9,085) ringed seals were present in the surveyed area during the peak molting period. Data on interannual variability in ringed seal abundance suggested higher numbers of seals in Van Keulenfjorden in 2002 compared to 2003, while other fjords with very stable ice cover showed no statistical differences. Poor ice conditions in general in 2002 probably resulted in seals from a wide area coming to Van Keulenfjorden (a large fjord with stable ice in 2002). The total estimated number of ringed seals present in the study area at the time of the survey must be regarded as a population index, or at least a minimum estimate for the area, because it does not account for individuals leaving and arriving, which might account for a considerable number of animals. The same situation is likely the case for many other studies reporting aerial census data for ringed seals. To achieve accurate estimates of population sizes from aerial surveys, more extensive knowledge of ringed seal behavior will be required.

Krafft, B.A.; Kovacs, K.M.; Andersen, M.; Aars, J.; Lydersen, C.; Ergon, T.; Haug, T.

2006-01-01

358

Chemoreceptors of crustaceans: similarities to receptors for neuroactive substances in internal tissues.  

PubMed Central

A description is given of crustacean chemosensory systems and the neurophysiological procedures used to study them. Their response properties and tuning characteristics are discussed. A review is then provided of specific crustacean chemoreceptors that are stimulated selectively by either purine nucleotides, taurine, glutamate, or glycine, all of which have neuroactive properties in internal tissues. Two distinctly different types of purinergic chemoreceptors occur on the antennules of the spiny lobster. P1-like chemoreceptors have a potency sequence of AMP greater than ADP greater than ATP greater than adenosine and show a strict structural requirement for the ribose phosphate moiety. P2-like chemoreceptors have a potency sequence of ATP greater than ADP greater than AMP or adenosine and show a broad sensitivity to nucleotide triphosphates with modifications in both the purine and ribose phosphate moieties. Sensilla containing the dendrites of chemosensory neurons also possess an ectonucleotidase(s) that inactivates excitatory nucleotides to yield adenosine which is subsequently internalized by a sensillar uptake system. Narrowly tuned taurinergic chemoreceptors are present on both the antennules and legs of lobsters. Although taurine itself is the most effective stimulant, the taurine analogs hypotaurine and beta-alanine are also very excitatory. Structure-activity studies indicate these chemoreceptors have marked similarities to taurine-sensitive systems in internal tissues of vertebrates. By contrast, comparative studies of glutamatergic chemoreceptors on the legs of lobsters indicate response spectra different from those of the glutamate receptors in lobster neuromuscular junctions and the three classes of excitatory amino acid receptors identified internally in vertebrates. Crustacean chemoreceptors for glycine, ecdysteroids, and pyridine are also described. The hypothesis that receptors for internal neuroactive agents may have originally evolved as external chemoreceptors of primitive aquatic organisms is discussed.

Carr, W E; Ache, B W; Gleeson, R A

1987-01-01

359

Habitats and biodiversity of decapod crustaceans in the SE Gulf of California, Mexico.  

PubMed

Samples of benthic macro-fauna were obtained in different habitats along and off the coast of Southern Sinaloa, Gulf of California, Mexico, from 1978 to 1991. Occurrence of species of decapod crustaceans was registered for six habitats, from the interidal to depth of 1200 m. A total of 299 species were collected, belonging to 53 families and including 17 species of Penaeoidea, 45 of Caridea, 6 of Thalassinidea, 5 of Palinura, 1 of Astacidea, 63 of Anomura, and 162 of Brachyura. Number of species varied considerably from one habitat to another. Highest biodiversity was observed in the Bay of Mazatlán, with 121 species, followed by the continental shelf and the rocky interidal (107 species each), the estuarine/coastal lagoons (48 species), the upper slope (18 species) and the sandy beaches (9 species). One species was found to be strictly insular-terrestrial and two are primarily associated with the flotsam. The results of this survey were compared with distribution data available for decapod crustaceans fauna from the SE Gulf of California and the Eastern Tropical Pacific zoogeographic region (ETP). The fauna collected represents 82% of the species cited for the area for coastal and shallow subtidal habitats (to ca. 115 m depth) and 57.6% of deep water (> 200 m) species known to occur in the Gulf of California. Except in two cases, similarity indices (SI) based on the number of species common to any pair of habitats were all very low. Continental shelf and the Bay of Mazatlán have 57 species in common (SI = 0.50), while rocky shore habitat and the Bay of Mazatlán share 27 species (SI = 0.24). Comparative studies of decapod crustaceans communities for the ETP are almost lacking altogether. Available data, however, indicate that biodiversity observed on Southern Sinaloa is so far the highest on record for marine and brackish-water habitants for a given section of this tropical zoogeographic region. PMID:9246369

Hendrickx, M E

1996-08-01

360

High-definition de novo sequencing of crustacean hyperglycemic hormone (CHH)-family neuropeptides.  

PubMed

A complete understanding of the biological functions of large signaling peptides (>4 kDa) requires comprehensive characterization of their amino acid sequences and post-translational modifications, which presents significant analytical challenges. In the past decade, there has been great success with mass spectrometry-based de novo sequencing of small neuropeptides. However, these approaches are less applicable to larger neuropeptides because of the inefficient fragmentation of peptides larger than 4 kDa and their lower endogenous abundance. The conventional proteomics approach focuses on large-scale determination of protein identities via database searching, lacking the ability for in-depth elucidation of individual amino acid residues. Here, we present a multifaceted MS approach for identification and characterization of large crustacean hyperglycemic hormone (CHH)-family neuropeptides, a class of peptide hormones that play central roles in the regulation of many important physiological processes of crustaceans. Six crustacean CHH-family neuropeptides (8-9.5 kDa), including two novel peptides with extensive disulfide linkages and PTMs, were fully sequenced without reference to genomic databases. High-definition de novo sequencing was achieved by a combination of bottom-up, off-line top-down, and on-line top-down tandem MS methods. Statistical evaluation indicated that these methods provided complementary information for sequence interpretation and increased the local identification confidence of each amino acid. Further investigations by MALDI imaging MS mapped the spatial distribution and colocalization patterns of various CHH-family neuropeptides in the neuroendocrine organs, revealing that two CHH-subfamilies are involved in distinct signaling pathways. PMID:23028060

Jia, Chenxi; Hui, Limei; Cao, Weifeng; Lietz, Christopher B; Jiang, Xiaoyue; Chen, Ruibing; Catherman, Adam D; Thomas, Paul M; Ge, Ying; Kelleher, Neil L; Li, Lingjun

2012-10-01

361

Endogenous production of endo-beta-1,4-glucanase by decapod crustaceans.  

PubMed

The potential ability to produce cellulase enzymes endogenously was examined in decapods crustaceans including the herbivorous gecarcinid land crabs Gecarcoidea natalis and Discoplax hirtipes, the amphibious freshwater crab Austrothelphusa transversa, the terrestrial hermit crab, Coenobita variabilis the parastacid crayfish Euastacus, and the crayfish Cherax destructor. The midgut gland of both G. natalis and D. hirtipes contained substantial total cellulase activities and activities of the cellulase enzymes endo-beta-1,4-glucanase and beta-glucosidase. With the exception of total cellulase and beta-glucosidase from D. hirtipes, the enzyme activities within the midgut gland were higher than those within the digestive juice. Hence, the enzyme activities appear to reside predominantly within midgut gland, providing indirect evidence for endogenous synthesis of cellulase enzymes by this tissue. A 900 bp cDNA fragment encoding a portion of the endo-beta-1,4-glucanase amino acid sequence was amplified by RT-PCR using RNA isolated from the midgut gland of C. destructor, Euastacus, A. transversa and C. variabilis. This provided direct evidence for the endogenous production of endo-beta-1,4-glucanase. The 900 bp fragment was also amplified from genomic DNA isolated from the skeletal muscle of G. natalis and D. hirtipes, clearly indicating that the gene encoding endo-beta-1,4-glucanase is also present in these two species. As this group of evolutionary diverse crustacean species possesses and expresses the endo-beta-1,4-glucanase gene it is likely that decapod crustaceans generally produce cellulases endogenously and are able to digest cellulose. PMID:16408228

Linton, Stuart M; Greenaway, Peter; Towle, David W

2006-01-12

362

Do osmoregulators have lower capacity of muscle water regulation than osmoconformers? A study on decapod crustaceans.  

PubMed

Decapod crustaceans occupy various aquatic habitats. In freshwater they are osmoregulators, while marine species are typically osmoconformers. Freshwater crustaceans are derived from marine ancestors. The hypothesis tested here was that osmoregulators, which can rely on salt transport by interface epithelia to prevent extracellular disturbance, would have a lower capacity of tissue water regulation when compared with osmoconformers. Four species of decapod crustaceans (the marine osmoconformer crab Hepatus pudibundus, and three osmoregulators of different habitats) have been exposed in vivo to a salinity challenge, for up to 24 hr. Osmoregulators were: the estuarine shrimp Palaemon pandaliformis, the diadromous freshwater shrimp Macrobrachium acanthurus, and the hololimnetic red crab Dilocarcinus pagei. H. pudibundus displayed hemolymph dilution already after 0.5 hr in 25 per thousand, reaching approximately 30% reduction in osmolality, but its muscle degree of hydration did not increase. To make the different in vivo salinity challenges directly comparable, the ratio between the maximum change in muscle hydration with respect to the control value measured for the species and the maximum change in hemolymph osmolality was calculated (x 1,000): H. pudibundus (25 per thousand, 8.1% kg H(2)O/mOsm x 10(3))>P. pandaliformis (2 per thousand, 9.2)>M. acanthurus (30 per thousand, 12.6)>P. pandaliformis (35 per thousand, 16.7)>D. pagei (7 per thousand, 60.4). Muscle slices submitted in vitro to a 30% osmotic challenge confirmed in vivo results. Thus, the estuarine/freshwater osmoregulators displayed a lower capacity to hold muscle tissue water than the marine osmoconformer, despite undergoing narrower variations in hemolymph osmolality. PMID:19844979

Foster, Clarice; Amado, Enelise M; Souza, Marta M; Freire, Carolina A

2010-02-01

363

A novel relapsing fever Borrelia sp. infects the salivary glands of the molted hard tick, Amblyomma geoemydae.  

PubMed

A novel relapsing fever Borrelia sp. was found in Amblyomma geoemydae in Japan. The novel Borrelia sp. was phylogenetically related to the hard (ixodid) tick-borne relapsing fever Borrelia spp. Borrelia miyamotoi and B. lonestari. The novel relapsing fever Borrelia sp. was detected in 39 A. geoemydae (39/274: 14.2%), of which 14 (14/274: 5.1%) were co-infected with the novel relapsing fever Borrelia sp. and Borrelia sp. tAG, one of the reptile-associated borreliae. Transstadial transmission of the novel relapsing fever Borrelia sp. occurred in the tick midgut and the salivary glands, although Borrelia sp. tAG was only detected in the tick midgut. The difference of the borrelial niche in molted ticks might be associated with borrelial characterization. PMID:22910061

Takano, Ai; Sugimori, Chieko; Fujita, Hiromi; Kadosaka, Teruki; Taylor, Kyle R; Tsubota, Toshio; Konnai, Satoru; Tajima, Tomoko; Sato, Kozue; Watanabe, Haruo; Ohnishi, Makoto; Kawabata, Hiroki

2012-07-27

364

Life cycle of tortoise tick Hyalomma aegyptium under laboratory conditions.  

PubMed

The tortoise tick Hyalomma aegyptium has a typical three-host life-cycle. Whereas its larvae and nymphs are less host-specific feeding on a variety of tetrapods, tortoises of the genus Testudo are principal hosts of adults. Ticks retained this trait also in our study under laboratory conditions, while adults were reluctant to feed on mammalian hosts. Combination of feeding larvae and nymphs on guinea pigs and feeding of adults on Testudo marginata tortoises provided the best results. Feeding period of females was on average 25 days (range 17-44), whereas males remain after female engorgement on tortoise host. Female pre-oviposition period was 14 days (3-31), followed by 24 days of oviposition (18-29). Pre-eclosion and eclosion, both together, takes 31 days (21-43). Larvae fed 5 days (3-9), then molted to nymphs after 17 days (12-23). Feeding period of nymphs lasted 7 days (5-10), engorged nymphs molted to adults after 24 days (19-26). Sex ratio of laboratory hatched H. aegyptium was nearly equal (1:1.09). The average weight of engorged female was 0.95 (0.72-1.12) g. The average number of laid eggs was 6,900 (6,524-7,532) per female, it was significantly correlated with weight of engorged female. Only 2.8% of engorged larvae and 1.8% of engorged nymphs remained un-molted and died. Despite the use of natural host species, feeding success of females reached only 45%. The whole life-cycle was completed within 147 days (98-215). PMID:21431927

Siroký, Pavel; Erhart, Jan; Petrželková, Klára J; Kamler, Martin

2011-03-24

365

Parasitic crustaceans as vectors of viruses, with an emphasis on three penaeid viruses.  

PubMed

Parasitic crustaceans serve as both hosts and vectors of viruses as well as of parasites and other microbial pathogenic agents. Few of the presumably numerous associations are known, but many can be anticipated. Recently, branchiurans and gnathiid isopods have been documented to host helminths and blood parasites. Because the agents can be observed readily with a microscope, these are better recognized than are the smaller viral, bacterial, and fungal agents. Some agents are harmful to the host of the crustacean parasite and others are not. Viruses probably fit both these categories, since viruses that do not appear pathogenic are often seen in ultrastructural images from a range of invertebrate hosts, including crustaceans. Some viruses have been implicated in causing disease in the host, at least under appropriate conditions. For example, lymphocystis virus may possibly be transmitted to the dermis of its fish hosts by copepods and to the visceral organs by a cymothoid isopod. Similarly, argulid branchiurans seem to transmit the viral agent of spring viremia of carp as well as carp pox, and copepods have been implicated in transmitting infectious hematopoietic necrosis, infectious salmon anemia, and infectious pancreatic necrosis to salmon. Other viruses can be vectored to their hosts through an additional animal. We exposed three viruses, Taura syndrome virus (TSV), white spot syndrome virus (WSSV), and yellowhead virus (YHV), all of which cause mortalities in wild and cultured penaeid shrimps, to crustacean parasites on fish and crabs. Using real-time polymerase chain reaction analysis, we show that TSV in the cyclopoid copepod Ergasilus manicatus on the gill filaments of the Gulf killifish, Fundulus grandis, the acorn barnacle Chelonibia patula on the carapace of the blue crab, Callinectes sapidus, and gooseneck barnacle Octolasmis muelleri on the gills of C. sapidus, can replicate for at least 2 weeks and establish what should be an infective dose. This result was additionally supported by positive in situ hybridization reactions. All three parasites are the first known non-penaeid hosts in which replication occurs. The mean log copy number of WSSV also suggested that replication occurred in E. manicatus. The mean log copy number of YHV gradually decreased in all three parasites and both hosts over the 2-week period. The vector relationships indicate an additional potential means of transmitting and disseminating the disease-causing agents to the highly susceptible and economically valuable penaeid shrimp hosts. PMID:21669853

Overstreet, Robin M; Jovonovich, Jean; Ma, Hongwei

2009-06-14

366

Measurement of DNA damage and apoptosis in Molt-4 cells after in vitro exposure to radiofrequency radiation.  

PubMed

To determine whether exposure to radiofrequency (RF) radiation can induce DNA damage or apoptosis, Molt-4 T lymphoblastoid cells were exposed with RF fields at frequencies and modulations of the type used by wireless communication devices. Four types of frequency/modulation forms were studied: 847.74 MHz code-division multiple-access (CDMA), 835.62 MHz frequency-division multiple-access (FDMA), 813.56 MHz iDEN(R) (iDEN), and 836.55 MHz time-division multiple-access (TDMA). Exponentially growing cells were exposed to RF radiation for periods up to 24 h using a radial transmission line (RTL) exposure system. The specific absorption rates used were 3.2 W/kg for CDMA and FDMA, 2.4 or 24 mW/kg for iDEN, and 2.6 or 26 mW/kg for TDMA. The temperature in the RTLs was maintained at 37 degrees C +/- 0.3 degrees C. DNA damage was measured using the single-cell gel electrophoresis assay. The annexin V affinity assay was used to detect apoptosis. No statistically significant difference in the level of DNA damage or apoptosis was observed between sham-treated cells and cells exposed to RF radiation for any frequency, modulation or exposure time. Our results show that exposure of Molt-4 cells to CDMA, FDMA, iDEN or TDMA modulated RF radiation does not induce alterations in level of DNA damage or induce apoptosis. PMID:14731070

Hook, Graham J; Zhang, Peng; Lagroye, I; Li, Li; Higashikubo, Ryuji; Moros, Eduardo G; Straube, William L; Pickard, William F; Baty, Jack D; Roti Roti, Joseph L

2004-02-01

367

Binding sites of crustacean hyperglycemic hormone and its second messengers on gills and hindgut of the green shore crab, Carcinus maenas: A possible osmoregulatory role  

Microsoft Academic Search

To determine the possible involvement of crustacean hyperglycemic hormone (CHH) in osmoregulation in crustaceans, ligand binding and second messenger assays were performed on gills and hindgut preparations of the green shore crab Carcinus maenas, whilst midgut gland, previously known as one of the target tissues of CHH served as a control tissue. Classical receptor binding analyses using [125I]CHH by saturation

J. Sook Chung; S. G. Webster

2006-01-01

368

Analysis of the expression pattern of Mysidium columbiae wingless provides evidence for conserved mesodermal and retinal patterning processes among insects and crustaceans  

Microsoft Academic Search

The Wnt family includes a number of genes, such as wingless (wg), which encode secreted glycoproteins that function in numerous developmental patterning processes. In order to gain a better understanding of crustacean pattern formation, a wg orthologue was cloned from the malacostracan crustacean Mysidium columbiae (mysid), and the expression pattern of this gene was compared with that of Drosophila wg.

Molly Duman-Scheel; Nicole Pirkl; Nipam H. Patel

2002-01-01

369

[Effect of human blood feeding on the fecundity, fertility and biological cycle of Rhodnius prolixus (Hemiptera: Reduviidae)].  

PubMed

The effect of several human blood fractions artificially fed to Rhodnius prolixus Stal 1859 on oviposture (fecundity), egg-hatching (fertility) and life cycle was observed. Specimens fed on man's blood were more fecund than those fed with woman's blood. There were no significant differences in fertility related to host sex. The nymphal development time and number of feedings to molt to the following instar were estimated. Animals fed only on blood plasm did not finish nymphal development, while those fed only blood red cells ended their life cycle in the third nymphal instar. Total life cycle lasts 129 days in individuals fed with whole blood. PMID:11935922

Aldana, E; Lizano, E; Valderrama, A

2001-06-01

370

Cytarabine and paclitaxel exhibit different cell-cycle specificities in different cell growing status  

Microsoft Academic Search

Objective  To investigate the cell-cycle specificites of cytarabine and paclitaxel in different growing status of target cell.\\u000a \\u000a \\u000a \\u000a Methods  Using flow cytometry, we tested the cell-cycle specificities of cytarabine and paclitaxel on acute lymphocte leukemia cell\\u000a line Molt-4 in different growing status and on clinical acute lymphocyte leukemia specimens in vitro as well as in leukemia patients in vivo.\\u000a \\u000a \\u000a \\u000a Results  Cytarabine induced S phase

Peng Zhang; Yi Zhou; Deding Tao; Jianfeng Zhou; Jianping Gong

2006-01-01

371

Melatonin: Neuritogenesis and neuroprotective effects in crustacean x-organ cells  

PubMed Central

Melatonin has both neuritogenic and neuroprotective effects in mammalian cell lines such as neuroblastoma cells. The mechanisms of action include receptor-coupled processes, direct binding and modulation of calmodulin and protein kinase C, and direct scavenging of free radicals. While melatonin is produced in invertebrates and has influences on their physiology and behavior, little is known about its mechanisms of action. We studied the influence of melatonin on neuritogenesis in well-differentiated, extensively-arborized crustacean x-organ neurosecretory neurons. Melatonin significantly increased neurite area in the first 24 h of culture. The more physiological concentrations, 1 nM and 1 pM, increased area at 48 h also, whereas the pharmacological 1?M concentration appeared to have desensitizing effects by this time. Luzindole, a vertebrate melatonin receptor antagonist, had surprising and significant agonist-like effects in these invertebrate cells. Melatonin receptors have not yet been studied in invertebrates. However, the presence of membrane-bound receptors in this population of crustacean neurons is indicated by this study. Melatonin also has significant neuroprotective effects, reversing the inhibition of neuritogenesis by 200 and 500 ?M hydrogen peroxide. Because this is at least in part a direct action not requiring a receptor, melatonin’s protection from oxidative stress is not surprisingly phylogenetically-conserved.

Cary, Gregory A.; Cuttler, Anne S.; Duda, Kirsten A.; Kusema, Escar T.; Myers, Jennifer A.; Tilden, Andrea R.

2011-01-01

372

The origin of crustaceans: new evidence from the Early Cambrian of China.  

PubMed Central

One of the smallest arthropods recently discovered in the Early Cambrian Maotianshan Shale Lagerstätte is described. Ercaia gen. nov. has an untagmatized trunk bearing serially repeated biramous appendages (long and segmented endopods and flap-like exopods), a head with an acron bearing stalked lateral eyes and a sclerite and two pairs of antennae. The position of this 520 million-year-old tiny arthropod within the Crustacea is supported by several anatomical features: (i) a head with five pairs of appendages including two pairs of antennae, (ii) highly specialized antennae (large setose fans with a possible function in feeding), and (iii) specialized last trunk appendages (segmented pediform structures fringed with setae). The segmentation pattern of Ercaia (5 head and 13 trunk) is close to that of Maxillopoda but lacks the trunk tagmosis of modern representatives of the group. Ercaia is interpreted as a possible derivative of the stem group Crustacea. Ercaia is likely to have occupied an ecological niche similar to those of some Recent meiobenthic organisms (e.g. copepods living in association with sediment). This new fossil evidence supports the remote ancestry of crustaceans well before the Late Cambrian and shows, along with other fossil data (mainly Early Cambrian in China), that a variety of body plans already coexisted among the primitive crustacean stock.

Chen, J Y; Vannier, J; Huang, D Y

2001-01-01

373

Digestive Enzymes of the Crustaceans Munida and Their Application in Cheese Manufacturing: A Review  

PubMed Central

Crustaceans Munida (fam. Galatheideae, ord. Decapodi) were fished in the Southern Adriatic Sea and their proteolytic activities were characterized and tested for potential application in cheese manufacturing. Enzymes extracted from whole crustaceans, mainly serine proteases, showed high caseinolytic and moderate clotting activities. Analysis by 2D zymography of the digestive enzymes extracted from Munida hepatopancreas, showed the presence of several isotrypsin- and isochymotrypsin-like enzymes in the range of 20–34 kDa and 4.1–5.8 pI. Moreover, specific enzymatic assays showed the presence of aminopeptidases and carboxypeptidases A and B. Overall, optimum activity was achieved at pH 7.5 and 40–45 °C. Caseinolytic activity, determined both spectrophotometrically and by SDS gel electrophoresis, indicated higher activity on ?-casein than on ?-casein. Miniature cheddar-type cheeses and Pecorino-type cheeses were manufactured by adding starter, rennet and Munida extracts to milk. Reverse-phase HPLC and MALDI-ToF mass spectrometry showed a more complex pattern of proteolytic products in cheeses made using Munida instead of chymosin. Munida extracts were found to degrade the chymosin-derived ?-casein fragment f193–209, one of the peptides associated with bitterness in cheese. In conclusion, Munida digestive enzymes represent a promising tool for development of new cheese products and shorten cheese ripening when used either alone or in addition to calf rennet.

Rossano, Rocco; Larocca, Marilena; Riccio, Paolo

2011-01-01

374

Skeletal adaptations for forwards and sideways walking in three species of decapod crustaceans.  

PubMed

Crustaceans have been successfully employed to study legged locomotion for decades. Most studies have focused on either forwards-walking macrurans, or sideways-walking brachyurans. Libinia emarginata is a Majoid crab (Brachyura) and as such belongs to the earliest group to have evolved the crab form from homoloid ancestors. Unlike most brachyurans, Libinia walks forwards 80% of the time. We employed standard anatomical techniques and motion analysis to compare the skeleton, stance, and the range of motion of the legs of Libinia to the sideways-walking green shore crab (Carcinus maenas), and to the forwards-walking crayfish (Procambarus clarkii). We found animals tended to have greater ranges of motion for joints articulating in the preferred direction of locomotion. Leg segments proximal to such joints were comparatively longer. Thorax elongation, leg length and placement at rest also reflected walking preference. Comparative studies of walking in Libinia and other brachyurans may shed light on the neuroethology of legged locomotion, and on the anatomical and physiological changes necessary for sideways-walking in crustaceans. PMID:18089130

Vidal-Gadea, A G; Rinehart, M D; Belanger, J H

2007-07-05

375

Axogenesis in the central and peripheral nervous system of the amphipod crustacean Orchestia cavimana.  

PubMed

We describe the formation of the major axon pathways in the embryonic central and peripheral nervous systems of the amphipod crustacean Orchestia cavimana Heller, 1865 by means of antibody staining against acetylated alpha-tubulin. The data add to a long list of previous studies of various other aspects of development in Orchestia and provide a basis for future studies of neurogenesis on a deeper cellular and molecular level. Orchestia exhibits a tripartite dorsal brain, which is a characteristic feature of euarthropods. Its anlagen are the first detectable structures in the developing nervous system and can be traced back to distinct neuronal cell clusters in the early embryo. The development of the ventral nervous system proceeds with an anteroposterior gradient of development. In each trunk segment, the longitudinal connectives and the anterior commissure form first, followed by the intersegmental nerve, the posterior commissure and segmental nerves, respectively. A single commissure of a vestigial seventh pleonal segment is found. In the peripheral nervous system we observe a spatial and temporal pattern of leg innervation, which is strikingly similar in both limb types, the uniramous pereopods and the biramous pleopods. A proximal leg nerve splitting distally into two separated nerves probably reflects a general feature of crustaceans. PMID:21392360

Ungerer, Petra; Geppert, Maria; Wolff, Carsten

2011-03-01

376

Digestive enzymes of the crustaceans Munida and their application in cheese manufacturing: a review.  

PubMed

Crustaceans Munida (fam. Galatheideae, ord. Decapodi) were fished in the Southern Adriatic Sea and their proteolytic activities were characterized and tested for potential application in cheese manufacturing. Enzymes extracted from whole crustaceans, mainly serine proteases, showed high caseinolytic and moderate clotting activities. Analysis by 2D zymography of the digestive enzymes extracted from Munida hepatopancreas, showed the presence of several isotrypsin- and isochymotrypsin-like enzymes in the range of 20-34 kDa and 4.1-5.8 pI. Moreover, specific enzymatic assays showed the presence of aminopeptidases and carboxypeptidases A and B. Overall, optimum activity was achieved at pH 7.5 and 40-45 °C. Caseinolytic activity, determined both spectrophotometrically and by SDS gel electrophoresis, indicated higher activity on ?-casein than on ?-casein. Miniature cheddar-type cheeses and Pecorino-type cheeses were manufactured by adding starter, rennet and Munida extracts to milk. Reverse-phase HPLC and MALDI-ToF mass spectrometry showed a more complex pattern of proteolytic products in cheeses made using Munida instead of chymosin. Munida extracts were found to degrade the chymosin-derived ?-casein fragment f193-209, one of the peptides associated with bitterness in cheese. In conclusion, Munida digestive enzymes represent a promising tool for development of new cheese products and shorten cheese ripening when used either alone or in addition to calf rennet. PMID:21822412

Rossano, Rocco; Larocca, Marilena; Riccio, Paolo

2011-07-07

377

Parasite transfer from crustacean to fish hosts in the Lübeck Bight, SW Baltic Sea  

NASA Astrophysics Data System (ADS)

Four helminth parasites out of 19 species found in the Lübeck Bight, Baltic Sea, were chosen for investigations on the transfer from invertebrate to small-sized fish hosts: larvae of the tapeworms Schistocephalus sp. and Bothriocephalus sp. (Cestoda) living in planktonic copepods as primary hosts; Podocotyle atomon (Digenea) and Hysterothylacium sp. (Nematoda) were found in benthic crustaceans, especially Gammarus spp. These hosts were the prey of 3 gobiid fishes, Gobiusculus flavescens (feeding mainly on plankton), Pomatoschistus minutus (preferring benthos), and P. pictus (feeding more on plankton than benthos). Because the fishes selected smaller sizes of crustaceans, they ingested all stages of the copepods but only the smaller-sized groups of gammarids which were often less infested by parasites. In order to evaluate the probability for a fish to be parasitized by a helminth, an infestation potential index (IP) was calculated. Podocotyle atomon and Hysterothylacium sp. revealed an IP which was far lower in gobies than expected when the prevalences of the previous hosts were taken into consideration. The IP of tapeworm larvae was mainly influenced by the feeding pressure of the gobiid predators, which might change with developmental stage and season. It is concluded that parasite transfer to the next host decreases when sizes of prey and predator differ only moderately. This mechanism can reduce the numbers of parasites transferred to less suitable or wrong hosts.

Zander, C. D.; Groenewold, S.; Strohbach, U.

1994-03-01

378

Evidence for widespread Wolbachia infection in isopod crustaceans: molecular identification and host feminization.  

PubMed

Wolbachia are maternally inherited, intracellular, alpha proteobacteria that infect a wide range of arthropods. They cause three kinds of reproductive alterations in their hosts: cytoplasmic incompatibility, parthenogenesis and feminization. There have been many studies of the distribution of Wolbachia in arthropods, but very few crustacean species are known to be infected. We investigated the prevalence of Wolbachia in 85 species from five crustacean orders. Twenty-two isopod species were found to carry these bacteria. The bacteria were found mainly in terrestrial species, suggesting that Wolbachia came from a continental environment. The evolutionary relationships between these Wolbachia strains were determined by sequencing bacterial genes and by interspecific transfers. All the bacteria associated with isopods belonged to the Wolbachia B group, based on 16S rDNA sequence data. All the terrestrial isopod symbionts in this group except one formed an independent clade. The results of interspecific transfers show evidence of specialization of Wolbachia symbionts to their isopod hosts. They also suggest that host species plays a more important role than bacterial phylogeny in determining the phenotype induced by Wolbachia infection. PMID:9684374

Bouchon, D; Rigaud, T; Juchault, P

1998-06-22

379

Comparative toxicity of pyrethroid insecticides to two estuarine crustacean species, Americamysis bahia and Palaemonetes pugio.  

PubMed

Pyrethroid insecticides are widely used on agricultural crops, as well as for nurseries, golf courses, urban structural and landscaping sites, residential home and garden pest control, and mosquito abatement. Evaluation of sensitive marine and estuarine species is essential for the development of toxicity testing and risk-assessment protocols. Two estuarine crustacean species, Americamysis bahia (mysids) and Palaemonetes pugio (grass shrimp), were tested with the commonly used pyrethroid compounds, lambda-cyhalothrin, permethrin, cypermethrin, deltamethrin, and phenothrin. Sensitivities of adult and larval grass shrimp and 7-day-old mysids were compared using standard 96-h LC(50) bioassay protocols. Adult and larval grass shrimp were more sensitive than the mysids to all the pyrethroids tested. Larval grass shrimp were approximately 18-fold more sensitive to lambda-cyhalothrin than the mysids. Larval grass shrimp were similar in sensitivity to adult grass shrimp for cypermethrin, deltamethrin, and phenothrin, but larvae were approximately twice as sensitive to lambda-cyhalothrin and permethrin as adult shrimp. Acute toxicity to estuarine crustaceans occurred at low nanogram per liter concentrations of some pyrethroids, illustrating the need for careful regulation of the use of pyrethroid compounds in the coastal zone. © 2013 Wiley Periodicals, Inc. Environ Toxicol, 2013. PMID:23364944

E Delorenzo, Marie; Key, Peter B; Chung, Katy W; Sapozhnikova, Yelena; Fulton, Michael H

2013-01-30

380

Probing the evolution of appendage specialization by Hox gene misexpression in an emerging model crustacean  

PubMed Central

Changes in the expression of Hox genes have been widely linked to the evolution of animal body plans, but functional demonstrations of this relationship have been impeded by the lack of suitable model organisms. A classic case study involves the repeated evolution of specialized feeding appendages, called maxillipeds, from anterior thoracic legs, in many crustacean lineages. These leg-to-maxilliped transformations correlate with the loss of Ultrabithorax (Ubx) expression from corresponding segments, which is proposed to be the underlying genetic cause. To functionally test this hypothesis, we establish tools for conditional misexpression and use these to misexpress Ubx in the crustacean Parhyale hawaiensis. Ectopic Ubx leads to homeotic transformations of anterior appendages toward more posterior thoracic fates, including maxilliped-to-leg transformations, confirming the capacity of Ubx to control thoracic (leg) versus gnathal (feeding) segmental identities. We find that maxillipeds not only are specified in the absence of Ubx, but also can develop in the presence of low/transient Ubx expression. Our findings suggest a path for the gradual evolutionary transition from thoracic legs to maxillipeds, in which stepwise changes in Hox gene expression have brought about this striking morphological and functional transformation.

Pavlopoulos, Anastasios; Kontarakis, Zacharias; Liubicich, Danielle M.; Serano, Julia M.; Akam, Michael; Patel, Nipam H.; Averof, Michalis

2009-01-01

381

Do the neurohormones VIH (vitellogenesis inhibiting hormone) and CHH (crustacean hyperglycemic hormone) of crustaceans have a common precursor? Immunolocalization of VIH and CHH in the X-organ sinus gland complex of the lobster, Homarus americanus  

Microsoft Academic Search

The present study deals with the location of the vitellogenesis inhibiting hormone (VIH)-producing cells in the eyestalk of the lobster Homarus americanus. In the present study, the neurosecretory pathways of VIH in Homarus, have been described immunocytochemically by use of a mouse serum against Homarus VIH. The location of the VIH cells was compared with the location of the crustacean

JANINE KALLEN; JEAN-JACQUES MEUSY

1989-01-01

382

Arsenic trioxide induces apoptosis in cells of MOLT4 and its daunorubicin-resistant cell line via depletion of intracellular glutathione, disruption of mitochondrial membrane potential and activation of caspase-3  

Microsoft Academic Search

PurposeTo demonstrate that arsenic trioxide (As 2O 3) induces apoptosis via a mitochondrial pathway in both parent T lymphoblastoid leukemia MOLT-4 cells and cells of its daunorubicin-resistant subline, MOLT-4\\/DNR, expressing functional P-gp.MethodsCell growth was measured using an MTT assay. Cell viability was determined using a dye exclusion test. Intracellular glutathione (GSH) was measured using a glutathione assay kit. Mitochondrial membrane

Xiao-Mei Hu; Toshihiko Hirano; Kitaro Oka

2003-01-01

383

Comparative strategies of heavy metal accumulation by crustaceans: zinc, copper and cadmium in a decapod, an amphipod and a barnacle  

Microsoft Academic Search

This study investigates the comparative strategies of accumulation under standardised laboratory conditions of the essential metals zinc and copper, and the non-essential metal cadmium by three crustaceans of different taxa; vizPalaemon elegans Rathke (Malacostraca: Eucarida: Decapoda),Echinogammarus pirloti (Sexton & Spooner) (Malacostraca: Peracarida: Amphipoda) and the barnacleElminius modestus Darwin (Cirripedia: Thoracica).

P. S. Rainbow; S. L. White

1989-01-01

384

Analysis of the factors affecting crustacean trawl fishery catch rates in the northern Tyrrhenian Sea (western Mediterranean)  

Microsoft Academic Search

The aim of this study was to analyse the main factors affecting catch rates of the most important decapod crustaceans of the bottom trawl fishery in the northern Tyrrhenian Sea, western Mediterranean. Catch per unit effort (CPUE) data (kg\\/fishing day\\/boat) of deep water rose shrimp, Parapenaeus longirostris, Norway lobster, Nephrops norvegicus, and red shrimps, Aristaemorpha foliacea and Aristeus antennatus, were

Mario Sbrana; Paolo Sartor; Paola Belcari

2003-01-01

385

Identification and isolation of a spiroplasma pathogen from diseased freshwater prawns, Macrobrachium rosenbergii, in China: A new freshwater crustacean host  

Microsoft Academic Search

Disease epizootics in freshwater cultured crustaceans, including freshwater prawns (Macrobrachium rosenbergii), gained high attention recently in Jiangsu, China due to intensive development of freshwater aquaculture and their susceptibility to massive mortalities. Morphological observation indicated that the pathogen in diseased M. rosenbergii had a helical morphology and lacked a cell wall. The agent could infect hemocytes and all the connective tissues

Tingming Liang; Xinlun Li; Jie Du; Wei Yao; Guiyao Sun; Xuehong Dong; Zhiguo Liu; Jiangtao Ou; Qingguo Meng; Wei Gu; Wen Wang

2011-01-01

386

INFLUENCE OF SALINITY ON HABITAT UTILIZATION OF OYSTER REEFS BY RESIDENT FISHES AND DECAPOD CRUSTACEANS IN THE CALOOSAHATCHEE ESTUARY, FLORIDA.  

EPA Science Inventory

A spatiotemporal comparison of habitat suitability of oyster reefs for fishes and decapod crustaceans was conducted for the lower Caloosahatchee Estuary, Florida. Lift nets (1-m2) containing 5 liters (volume displacement) of oyster clusters were deployed monthly at three sites al...

387

[Biochemical composition of crustacean zooplankton and their grazing on phytoplankton and ciliated protozoans in a recently founded reservoir (Sahela, Morocco].  

PubMed

In order to assess the impact of crustacean zooplankton on phytoplankton and protozoan ciliates in the Sahela reservoir under semi-arid climate, we conducted experiments during the period from July to December 1999 at the deepest point in the lake (15 m). Samplings and measurements were carried out in diffusion chambers submerged in situ over a period of 7 h without (control chambers) and with (experimental chambers) crustacean zooplankton. During these experiments, counts were conducted on phytoplankton and ciliates to determine the abundance and the mortality of these organisms due to zooplankton in each diffusion chambers at t = 0 and t = 7 h of incubation. The study showed that the growth rates of phytoplankton and ciliates populations varied between 0.02 and 0.05 h-1 and from 0.01 to 0.07 h-1, respectively. The mortality caused by zooplankton grazing fluctuated from 0.07 to 0.2 h-1 of phytoplankton and from 0.01 to 0.2 h-1 of ciliates. These mortalities were significantly and positively correlated with the growth rates (r = 0.8; p < 0.02; n = 9). Moreover, the heavy predation by the crustacean zooplankton was exerted on small-sized phytoplankton and ciliates and we demonstrated the relationships between protozoans and zooplankton for the transfer of matter and energy in aquatic food webs. Furthermore, the crustacean zooplankton metabolism was different, whether zooplankton was present in diffusion chambers or in the lake. PMID:14608696

Derraz, Khalid; Elalami, Rachid; Atiki, Ilham; Mhamdi, Mohamed Alaoui

2003-08-01

388

Habitat and feeding preferences of crustacean mesoherbivores inhabiting the brown seaweed Ascophyllum nodosum (L.) Le Jol. and its epiphytic macroalgae  

Microsoft Academic Search

Habitat and feeding preferences of crustacean mesoherbivores inhabiting the brown alga Ascophyllum nodosum (L.) Le Jol. and its macroepiphytes were examined on the Swedish west coast. After an initial survey of the epifauna, three species of mesoherbivores, the isopods Idotea granulosa Rahtke and Jaera albifrons Leach, and the amphipod Gammarus locusta (L.), were selected for further studies. The role of

Henrik Pavia; Herman Carr; Per Åberg

1999-01-01

389

Subcellular distribution of zinc and cadmium in the hepatopancreas and gills of the decapod crustacean Penaeus indicus  

Microsoft Academic Search

The decapod crustacean Penaeus indicus accumulated Cd and Zn in different subcellular compartments of hepatopancreas and gill cells. Most of the Cd and part of the Zn accumulates within the soluble fraction of the cells, while the remainder of the Zn is found in insoluble inclusions, associated with P, Ca, Mg and Si in B-, F- and R-cells in the

G. Nunez-Nogueira; C. Mouneyrac; J. C. Amiard; P. S. Rainbow

2006-01-01

390

Hypothesis for heritable, anti-viral immunity in crustaceans and insects  

PubMed Central

Background It is known that crustaceans and insects can persistently carry one or more viral pathogens at low levels, without signs of disease. They may transmit them to their offspring or to naïve individuals, often with lethal consequences. The underlying molecular mechanisms have not been elucidated, but the process has been called viral accommodation. Since tolerance to one virus does not confer tolerance to another, tolerance is pathogen-specific, so the requirement for a specific pathogen response mechanism (memory) was included in the original viral accommodation concept. Later, it was hypothesized that specific responses were based on the presence of viruses in persistent infections. However, recent developments suggest that specific responses may be based on viral sequences inserted into the host genome. Presentation of the hypothesis Non-retroviral fragments of both RNA and DNA viruses have been found in insect and crustacean genomes. In addition, reverse-transcriptase (RT) and integrase (IN) sequences are also common in their genomes. It is hypothesized that shrimp and other arthropods use these RT to recognize "foreign" mRNA of both RNA and DNA viruses and use the integrases (IN) to randomly insert short cDNA sequences into their genomes. By chance, some of these sequences result in production of immunospecific RNA (imRNA) capable of stimulating RNAi that suppresses viral propagation. Individuals with protective inserts would pass these on to the next generation, together with similar protective inserts for other viruses that could be amalgamated rapidly in individual offspring by random assortment of chromosomes. The most successful individuals would be environmentally selected from billions of offspring. Conclusion This hypothesis for immunity based on an imRNA generation mechanism fits with the general principle of invertebrate immunity based on a non-host, "pattern recognition" process. If proven correct, understanding the process would allow directed preparation of vaccines for selection of crustacean and insect lines applicable in commercial production species (e.g., shrimp and bees) or in control of insect-borne diseases. Arising from a natural host mechanism, the resulting animals would not be artificially, genetically modified (GMO). Reviewers This article was reviewed by Akria Shibuya, Eugene V. Koonin and L. Aravind.

Flegel, Timothy W

2009-01-01

391

Regulation of the Transcription Factor E75 by 20-Hydroxyecdysone and Juvenile Hormone in the Epidermis of the Tobacco Hornworm, Manduca sexta,during Larval Molting and Metamorphosis  

Microsoft Academic Search

The homolog of the ecdysteroid-induced transcription factor E75A inDrosophila melanogasterwas cloned from the tobacco hornworm,Manduca sexta,and its developmental expression and hormonal regulation were analyzed. Both E75A and E75B mRNAs were found in the abdominal epidermis during both the larval and the pupal molts, with E75A appearing before E75B, coincident with the rise of ecdysteroid. Exposure of either fourth or fifth

Baohua Zhou; Kiyoshi Hiruma; Marek Jindra; Tetsuro Shinoda; William A. Segraves; Fae Malone; Lynn M. Riddiford

1998-01-01

392

Effects of light intensity on molting, growth, precocity, digestive enzyme activity, and chemical composition of juvenile Chinese mitten crab Eriocheir sinensis  

Microsoft Academic Search

A 74-day growth trial was carried out to investigate the effects of light intensity on the juvenile Chinese mitten crab, Eriocheir sinensis, under semi-natural conditions. The experiment had three light intensity treatment groups, natural light (NL), middle light\\u000a (ML), and low light (LL), as light intensity became weaker. The results indicated that light intensity had no significant\\u000a effect on molting

Xiaowu LI; Zhongjie LI; Jiashou LIU; Tanglin Zhang; Chaowen Zhang

2011-01-01

393

The IMP dehydrogenase inhibitor mycophenolic acid antagonizes the CTP synthetase inhibitor 3-deazauridine in MOLT3 human leukemia cells: A central role for phosphoribosyl pyrophosphate  

Microsoft Academic Search

Mycophenolic acid, an inhibitor of the enzyme IMP dehydrogenase, antagonizes the CTP synthetase inhibitor 3-deazauridine in its anti-proliferative effects on MOLT-3 human T leukemia cells. No depletion of CTP occurred, and decreased amounts of 3-deazauridine-triphosphate were measured in cells incubated with mycophenolic acid and 3-deazauridine. Most probably, these phenomena are related to the increased amounts of PRPP observed, which can

A. André Van Berg; Petra A. W. Mooyer; Henk Van Lenthe; Elisabeth H. Stet; Ronney A. De Abreu; André B. P. Van Kuilenburg; Albert H. Van Gennip

1995-01-01

394

Relationships between structure and molting hormonal activity of tebufenozide, methoxyfenozide, and their analogs in cultured integument system of Chilo suppressalis Walker  

Microsoft Academic Search

The molting hormonal activity of methoxyfenozide (RH-2485), tebufenozide (RH-5992), five analogs with various alkyl groups, and 18 acyl analogs was measured by using cultured integument of rice stem borers, Chilo suppressalis Walker. The hormonal activity of methoxyfenozide was remarkably high (EC50 = 1.1 × 10?9 M), being equivalent to that of tebufenozide (RH-5992). The hormonal activity of several tebufenozide analogs

Yoshiaki Nakagawa; Kazunari Hattori; Chieka Minakuchi; Soichi Kugimiya; Tamio Ueno

2000-01-01

395

Differences in the effect of ionizing radiation on NA\\/sup +\\/-dependent amino acid transport in human T (Molt4) and human B (RPMI 1788) lymphoid cells  

Microsoft Academic Search

We have investigated the effects of ionizing radiation (0.10 to 10 krad) on the Na\\/sup +\\/-dependent transport of 2-aminoisobutyric acid and the involvement of a plasma membrane sulfhydryl-protein component which modulates this transport system in a human T (Molt-4) and a B (RPMI 1788) lymphoid cell line. The radiosensitivity of this transport system and a putative sulfhydryl membrane regulatory component

L. Kwock; P. S. Lin; L. Ciborowski

1979-01-01

396

Long-term pyrene exposure of grass shrimp, Palaemonetes pugio, affects molting and reproduction of exposed males and offspring of exposed females.  

PubMed Central

The objective of this study was to investigate the impact of long-term pyrene exposure on molting and reproduction in the model estuarine invertebrate, the grass shrimp (Palaemonetes pugio). Grass shrimp were exposed to measured concentrations of 5.1, 15.0, and 63. 4 ppb (microg/L) pyrene for 6 weeks, during which time we determined molting and survivorship. At the end of the exposure, we immediately sacrificed some of the shrimp for biomarker (CYP1A and vitellin) analyses. The remaining shrimp were used to analyze fecundity and embryo survivorship during an additional 6 weeks after termination of pyrene exposure. Male shrimp at the highest pyrene dose (63 ppb) experienced a significant delay in molting and in time until reproduction, and showed elevated ethoxycoumarin o-deethylase (ECOD) activity immediately after the 6-week exposure period. In contrast, 63 ppb pyrene did not affect these parameters in female shrimp. Females produced the same number of eggs per body weight, with high egg viability (98-100%) at all exposure levels, but with decreased survival for the offspring of the 63-ppb pyrene-exposed females. In addition, vitellin levels were elevated only in females at 63 ppb pyrene after the 6-week exposure. We hypothesize that the elevated vitellin binds pyrene and keeps it biologically unavailable to adult females, resulting in maternal transfer of pyrene to the embryos. This would account for the lack of effect of pyrene exposure on ECOD activity, molting, and reproduction in the adult females, and for reduced survival of their offspring. Images Figure 1 Figure 2 Figure 3

Oberdorster, E; Brouwer, M; Hoexum-Brouwer, T; Manning, S; McLachlan, J A

2000-01-01

397

Release of Thy-1 from a human T cell line (Molt-3) by phosphatidylinositol-specific phospholipase C (PI-PLC)  

SciTech Connect

The mode of attachment of Thy-1 to cell surface is controversial. Recently, Low and Kincade showed by immunofluorescence that phosphatidylinositol is the membrane anchoring domain of murine Thy-1. Here they report that Thy-1 is cleaved from human T cells, but not B cells. Three lymphoblastoid cell lines, Molt-3, Raji (human B cell), and Yac-1 (mouse T cell), were radiolabelled with /sup 125/I. The labelled cells were washed with PBS and resuspended in buffer (RPMI-1640 with 20 mM HEPES). The cells were incubated with PI-PLC at 37/sup 0/C for 60 min, then centrifuged. /sup 125/I labelled proteins in the supernatant were precipitated with anti-Thy-1 antibodies, separated by SDS-PAGE, and detected by autoradiography. The results showed that two bands of approximately 16,000 and 18,000 daltons were present in the precipitate from PI-PLC-treated Molt-3 cells, but absent in that of untreated Molt-3 cells. No band was detectable in the case for Raji cells with or without PI-PLC. Two bands were detected in the precipitates from both PI-PLC-treated and untreated Yac-1 cells. There was considerable lysis of Yac-1 and Raji, but not Molt-3, cells during iodination. Cell lysis might have caused the release of Thy-1 by activation of endogenous PI-PLC. Their results indicate that human Thy-1, like murine Thy-1, is anchored to cell membrane via a lipid moiety containing phosphatidylinositol.

Tung, E.; Wang, I.Y.; Wang, A.C.

1986-03-05

398

Ethanolic extract of fermented Thunb induces human leukemic HL-60 and Molt-4 cell apoptosis via oxidative stress and a mitochondrial pathway.  

PubMed

Houttuynia cordata Thunb (HCT) is a medicinal plant of the Saururaceae family which features antimutagenic and antiviral properties. For extraction, the whole plants were fermented or non-fermented with yeast and ethanol then the whole plants were dried, ground and extracted with 95% ethanol or water. The aims of this study were to compare cytotoxic effects, apoptosis induction, and mechanism(s) with the ethanolic and water extracts of fermented and non-fermented HCT. Cytotoxicity was assessed using the MTT assay in human leukemic HL-60, Molt-4 and peripheral blood mononuclear cells (PBMCs). Apoptotic death was characterized by staining with propidium iodide and examined under a fluorescence microscope. Peroxide radical production and reduction of mitochondrial transmembrane potential (MTP) were determined using 2',7'-dichlorohydrofluorescein diacetate and 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, respectively. The expression of caspase-9 was identified by immunoblotting. The ethanolic extract of fermented HCT was cytotoxic to HL-60 >Molt- 4 > PBMCs, to a greater extent than the non-fermented preparation and the number of apoptotic cells was higher. The alcoholic (fermented) extract produced more radicals than the non-fermented in HL-60 cells but the converse was observed in Molt-4 cells. Reduction of MTP was found in HL-60 and Molt-4 cells treated with the alcoholic (fermented) extract and caspase-9 was cleaved dose-dependently in both cells. In conclusion, the alcoholic extract of fermented HCT was more toxic to human leukemic cells than the non-fermented and both cell lines underwent apoptosis via oxidative stress and a mitochondrial pathway. PMID:22393956

Banjerdpongchai, Ratana; Kongtawelert, Prachya

2011-01-01

399

Moult cycle specific differential gene expression profiling of the crab Portunus pelagicus  

Microsoft Academic Search

Background  Crustacean moulting is a complex process involving many regulatory pathways. A holistic approach to examine differential gene\\u000a expression profiles of transcripts relevant to the moulting process, across all moult cycle stages, was used in this study.\\u000a Custom cDNA microarrays were constructed for Portunus pelagicus. The printed arrays contained 5000 transcripts derived from both the whole organism, and from individual organs

Anna V Kuballa; Timothy A Holton; Brian Paterson; Abigail Elizur

2011-01-01

400

Paleozoic-Mesozoic crayfish from Antarctica: Earliest evidence of freshwater decapod crustaceans  

NASA Astrophysics Data System (ADS)

Discovery of an Early Permian claw from Antarctica extends the fossil record of crayfish by ˜65 m.y. and demonstrates that decapod crustaceans had radiated into freshwater habitats by the late Paleozoic. Burrows in Lower Triassic rocks of Antarctica are among the oldest apparently constructed by crayfish. Their morphology is similar to modern crayfish burrows, and this demonstrates that burrowing behavior was established early in the evolution of this group. The new discoveries show that the earliest Permian crayfish were distributed in high paleolatitudes of southernmost Pangea, where they lived in freshwater lakes fed by glacial meltwater. Modern crayfish habitat, used as a guide to crayfish temperature tolerance, indicates that summer temperatures of streams and lakes near the South Pole that supported the crayfish probably reached 10 20 °C during Permian-Triassic interglacial intervals.

Babcock, Loren E.; Miller, Molly F.; Isbell, John L.; Collinson, James W.; Hasiotis, Stephen T.

1998-06-01

401

Long-term fish and macro-crustacean community variation in a Mediterranean lagoon  

NASA Astrophysics Data System (ADS)

The fish and macro-crustacean community of the Vaccarès lagoon (Rhône River delta, South France) was sampled monthly from 1993 to 2002. The lagoon salinity shifted from 15 in 1993 to 5 in 1994-1997 and went back to 15 in 1999-2002. Connections with the sea also varied during the study period with larger openings in 1996-1997. During the study period, the community changed to revert in 2002 to a state similar to 1993. These changes consisted of a sequence of increased and decreased patterns of freshwater species and some marine species. Typical lagoon species tended to resist to salinity changes. Freshwater species colonised the lagoon when the salinity was low. Marine species may have varied both in relation to connections with the sea and to indirect effects of freshwater outflow. This study shows that community changes following environmental variations can be delayed in time, and emphasises the need for long-term studies.

Poizat, Gilles; Rosecchi, Elizabeth; Chauvelon, Philippe; Contournet, Pascal; Crivelli, Alain J.

2004-04-01

402

Determination of bioactivity of chemical fractions of liquid wastes using freshwater and saltwater algae and crustaceans  

SciTech Connect

Complex wastes from industrial and municipal outfalls were fractionated chemically and tested for toxicity with freshwater and saltwater algae and crustaceans. The organic fraction of each waste was subfractionated into acid-, base-, and neutral-extractable portions, and the inorganic fraction was subfractionated into its anion and cation components. All wastes affected growth of the algae Skeletonema costatum (saltwater) and Monoraphidium capricornutum (freshwater) or survival of Mysidopsis bahia (saltwater) and Daphnia magna (freshwater). Usually, bioactivity was limited to one or two subfractions. In some cases, algal growth was stimulated by a fraction or subfraction, whereas stimulation was not detected in whole waste. It is suggested that fractionation must be done in order to estimate the full potential impact of complex wastes on aquatic systems. The method can also be used to identify toxic factors before application of cost-effective control technology.

Walsh, G.E. (US Environmental Protection Agency, Gulf Breeze, FL); Garnas, R.L.

1983-03-01

403

Direct and indirect fitness consequences of female choice in a crustacean.  

PubMed

Understanding the evolution and maintenance of female mate choice requires information on both the benefits (the sum of direct and indirect benefits) and costs of selective mating. In this study, I assessed the fitness consequences of female mate choice in a freshwater crustacean. In Hyalella amphipods, males attempt to form precopulatory pairs with females. Large males, bearing large posterior gnathopods, tend to be over-represented in precopulatory pairs. I show that females receive both direct (reduced risk of predation while paired) and indirect (sexy sons) benefits from mating with these males. Furthermore, the behavioral mechanisms used to filter male phenotypes carry no detectable energetic cost for females. Thus, females that choose males with successful phenotypes are expected to have higher Darwinian fitness than females that mate at random. This study shows that direct and indirect selection act together to favor large male size, which explains the sexual size dimorphism and size-based mating biases observed in this species. PMID:18410531

Cothran, Rickey D

2008-07-01

404

Effects of sewage-impacted sediment on reproduction in the benthic crustacean Leptocheirus plumulosus.  

PubMed

Several organic contaminants in sewage effluent have been shown to elicit an estrogenic response in juvenile fish. Comparatively little emphasis has been placed on assessing these effects in marine invertebrates, particularly benthic organisms inhabiting sediment where lipophilic contaminants tend to persist. The present study examined reproductive effects in the benthic crustacean Leptocheirus plumulosus exposed to sewage-impacted sediment from Jamaica Bay, New York. Data from chronic 28-day tests showed a 50% reduction in the average number of young (juveniles + embryos) produced per surviving female in exposures to sediment from Jamaica Bay (JB). Nonylphenol ethoxylate ('NPEO) concentrations at this site were measured at 44.2 microg/g dw, concentrations two orders of magnitude higher than reference site concentrations in central Long Island Sound (CLIS). Dose-response studies with nonylphenol (NP) amended reference sediment, however, did not significantly affect reproduction suggesting that other contaminants may have contributed to the effects observed. PMID:12408626

Zulkosky, A M; Ferguson, P L; McElroy, A E

405

Unscheduled CDK1 activity in G1 phase of the cell cycle triggers apoptosis in X-irradiated lymphocytic leukemia cells  

Microsoft Academic Search

.  Cyclin-dependent kinase 1 (CDK1) is a major component of the cell cycle progression engine. Recently, several investigations\\u000a provided evidence demonstrating that unscheduled CDK1 activation may also be involved in apoptosis in cancerous cells. In\\u000a this article, we demonstrate that X-ray irradiation induced G1 arrest in MOLT-4 lymphocytic leukemia cells, the arrest being\\u000a accompanied by reduction in the activity of CDK2,

J. Wu; Y. Feng; D. Xie; X. Li; W. Xiao; D. Tao; J. Qin; J. Hu; K. Gardner; S. I. V. Judge; Q. Q. Li; J. Gong

2006-01-01

406

Astakine 2--the dark knight linking melatonin to circadian regulation in crustaceans.  

PubMed

Daily, circadian rhythms influence essentially all living organisms and affect many physiological processes from sleep and nutrition to immunity. This ability to respond to environmental daily rhythms has been conserved along evolution, and it is found among species from bacteria to mammals. The hematopoietic process of the crayfish Pacifastacus leniusculus is under circadian control and is tightly regulated by astakines, a new family of cytokines sharing a prokineticin (PROK) domain. The expression of AST1 and AST2 are light-dependent, and this suggests an evolutionarily conserved function for PROK domain proteins in mediating circadian rhythms. Vertebrate PROKs are transmitters of circadian rhythms of the suprachiasmatic nucleus (SCN) in the brain of mammals, but the mechanism by which they function is unknown. Here we demonstrate that high AST2 expression is induced by melatonin in the brain. We identify RACK1 as a binding protein of AST2 and further provide evidence that a complex between AST2 and RACK1 functions as a negative-feedback regulator of the circadian clock. By DNA mobility shift assay, we showed that the AST2-RACK1 complex will interfere with the binding between BMAL1 and CLK and inhibit the E-box binding activity of the complex BMAL1-CLK. Finally, we demonstrate by gene knockdown that AST2 is necessary for melatonin-induced inhibition of the complex formation between BMAL1 and CLK during the dark period. In summary, we provide evidence that melatonin regulates AST2 expression and thereby affects the core clock of the crustacean brain. This process may be very important in all animals that have AST2 molecules, i.e. spiders, ticks, crustaceans, scorpions, several insect groups such as Hymenoptera, Hemiptera, and Blattodea, but not Diptera and Coleoptera. Our findings further reveal an ancient evolutionary role for the prokineticin superfamily protein that links melatonin to direct regulation of the core clock gene feedback loops. PMID:23555281

Watthanasurorot, Apiruck; Saelee, Netnapa; Phongdara, Amornrat; Roytrakul, Sittiruk; Jiravanichpaisal, Pikul; Söderhäll, Kenneth; Söderhäll, Irene

2013-03-21

407

The Global Diversity of Parasitic Isopods Associated with Crustacean Hosts (Isopoda: Bopyroidea and Cryptoniscoidea)  

PubMed Central

Parasitic isopods of Bopyroidea and Cryptoniscoidea (commonly referred to as epicarideans) are unique in using crustaceans as both intermediate and definitive hosts. In total, 795 epicarideans are known, representing ?7.7% of described isopods. The rate of description of parasitic species has not matched that of free-living isopods and this disparity will likely continue due to the more cryptic nature of these parasites. Distribution patterns of epicarideans are influenced by a combination of their definitive (both benthic and pelagic species) and intermediate (pelagic copepod) host distributions, although host specificity is poorly known for most species. Among epicarideans, nearly all species in Bopyroidea are ectoparasitic on decapod hosts. Bopyrids are the most diverse taxon (605 species), with their highest diversity in the North West Pacific (139 species), East Asian Sea (120 species), and Central Indian Ocean (44 species). The diversity patterns of Cryptoniscoidea (99 species, endoparasites of a diverse assemblage of crustacean hosts) are distinct from bopyrids, with the greatest diversity of cryptoniscoids in the North East Atlantic (18 species) followed by the Antarctic, Mediterranean, and Arctic regions (13, 12, and 8 species, respectively). Dajidae (54 species, ectoparasites of shrimp, mysids, and euphausids) exhibits highest diversity in the Antarctic (7 species) with 14 species in the Arctic and North East Atlantic regions combined. Entoniscidae (37 species, endoparasites within anomuran, brachyuran and shrimp hosts) show highest diversity in the North West Pacific (10 species) and North East Atlantic (8 species). Most epicarideans are known from relatively shallow waters, although some bopyrids are known from depths below 4000 m. Lack of parasitic groups in certain geographic areas is likely a sampling artifact and we predict that the Central Indian Ocean and East Asian Sea (in particular, the Indo-Malay-Philippines Archipelago) hold a wealth of undescribed species, reflecting our knowledge of host diversity patterns.

Williams, Jason D.; Boyko, Christopher B.

2012-01-01

408

Evolutionary changes in the olfactory projection neuron pathways of eumalacostracan crustaceans.  

PubMed

Output from the olfactory lobe (primary olfactory center) of eumalacostracan crustaceans is transmitted to the medulla terminalis (MT) and hemiellipsoid body (HB) in the lateral protocerebrum (higher order center) by a large population of projection neurons. In eureptantian crustaceans (lobsters, crayfish, and crabs), these projection neurons also form the output pathway from an additional neuropil, the accessory lobe (higher order center), which appears to have arisen de novo in these animals. In a previous study of lobsters and crayfish we showed that whereas projection neurons innervating the olfactory lobe project primarily to the MT, those innervating the accessory lobe project exclusively to the HB (Sullivan and Beltz [ 2001a] J. Comp. Neurol. 441:9-22). In the present study, we used focal dye injections to examine the olfactory projection neuron pathways of representatives of four eumalacostracan taxa (Stomatopoda, Dendrobranchiata, Caridea, and Stenopodidea) that diverged from the eureptantian line prior to the appearance of the accessory lobe. These experiments were undertaken both to examine the evolution of the olfactory pathway in the Eumalacostraca and to provide insights into the changes in this pathway that accompanied the appearance of the accessory lobe. The innervation patterns of the olfactory projection neurons of the species examined were found to differ markedly, varying from that observed in the most basal taxon examined (Stomatopoda), in which the neurons primarily project to the MT, to those observed in the two highest taxa examined (Caridea and Stenopodidea), in which they primarily target the HB. These results suggest that substantial changes in the relative importance of the MT and HB within the olfactory pathway have occurred during the evolution of the Eumalacostraca. PMID:14755523

Sullivan, Jeremy M; Beltz, Barbara S

2004-02-23

409

Discrete Pulses of Molting Hormone, 20-Hydroxyecdysone, During Late Larval Development of Drosophila melanogaster: Correlations With Changes in Gene Activity  

PubMed Central

Periodic pulses of the insect steroid molting hormone 20-hydroxyecdysone (20E), acting via its nuclear receptor complex (EcR/USP), control gene expression at many stages throughout Drosophila development. However, during the last larval instar of some lepidopteran insects, subtle changes in titers of ecdysteroids have been documented, including the so-called "commitment peak". This small elevation of 20E reprograms the larva for metamorphosis to the pupa. Similar periods of ecdysteroid immunoreactivity have been observed during the last larval instar of Drosophila. However, due to low amplitude and short duration, along with small body size and staging difficulties, their timing and ecdysteroid composition have remained uncertain. Employing a rigorous regimen of Drosophila culture and a salivary gland reporter gene, Sgs3-GFP, we used RP-HPLC and differential ecdysteroid RIA analysis to determine whole body titers of 20E during the last larval instar. Three small peaks of 20E were observed at 8, 20 and 28 hr following ecdysis, prior to the well-characterized large peak around the time of pupariation. The possible regulation of 20E levels by biosynthetic P450 enzymes and the roles of these early peaks in coordinating gene expression and late larval development are discussed.

Warren, James T.; Yerushalmi, Yoram; Shimell, Mary Jane; O'Connor, Michael B.; Restifo, Linda; Gilbert, Lawrence I.

2008-01-01

410

Caspase-3-like activity determines the type of cell death following ionizing radiation in MOLT-4 human leukaemia cells  

PubMed Central

Caspases, a family of cysteine proteases, play a central role in the pathways leading to apoptosis. Recently, it has been reported that a broad spectrum inhibitor of caspases, the tripeptide Z-VAD-fmk, induced a switch from apoptosis to necrosis in dexamethasone-treated B lymphocytes and thymocytes. As such a cell death conversion could increase the efficiency of radiation therapy and in order to identify the caspases involved in this cell death transition, we investigated the effects of caspase-3-related proteases inhibition in irradiated MOLT-4 cells. Cells were pretreated with Ac-DEVD-CHO, an inhibitor of caspase-3-like activity, and submitted to X-rays at doses ranging from 1 to 4 Gy. Our results show that the inhibition of caspase-3-like activity prevents completely the appearance of the classical hallmarks of apoptosis such as internucleosomal DNA fragmentation or hypodiploid particles formation and partially the externalization of phosphatidylserine. However, this was not accompanied by any persistent increase in cell survival. Instead, irradiated cells treated by this inhibitor exhibited characteristics of a necrotic cell death. Therefore, functional caspase-3-subfamily not only appears as key proteases in the execution of the apoptotic process, but their activity may also influence the type of cell death following an exposure to ionizing radiation. © 2000 Cancer Research Campaign

Coelho, D; Holl, V; Weltin, D; Lacornerie, T; Magnenet, P; Dufour, P; Bischoff, P

2000-01-01

411

Digestive proteinase activity in corn earworm (Helicoverpa zea) after molting and in response to lowered redox potential.  

PubMed

Insect digestive proteinases are often strongly influenced by ambient physicochemical conditions, such as pH, ionic strength, and oxidation-reduction potential. Although the effects of the former two parameters are well documented, the influence of redox potential on catalytic rates of digestive enzymes is not well understood. In this study, we manipulated the midgut redox potential of a generalist caterpillar (the corn earworm, Helicoverpa zea) by augmenting artificial diet with dithiothreitol, a powerful thiol reducing agent that lowers the redox potential in the lumen by 40-45 mV. Effects on total proteolytic activity, as well as on elastase, chymotrypsin, trypsin, leucine aminopeptidase, and carboxypeptidase A and B activities were measured using azocasein and nitroanilide model substrates. The profiles of proteinase activities in the epithelium and lumen were also monitored on days 1, 2, and 3 after the molt in penultimate instar larvae. Although the reducing agent strongly inhibited the activity of some proteinases in vitro, ingestion of the reducing diet failed to affect in vivo proteinase activities. There was also no effect on larval relative growth, consumption, or digestive efficiencies. We conclude that dietary reducing agents must lower midgut redox potential to below -40 mV to significantly impact digestive efficiency. Arch. PMID:10918310

Johnson, K S; Felton, G W

2000-08-01

412

Multiple adaptive mechanisms affect asparagine synthetase substrate availability in asparaginase-resistant MOLT-4 human leukaemia cells.  

PubMed

Childhood acute lymphoblastic leukaemia is treated by combination chemotherapy with a number of drugs, almost always including the enzyme L-asparaginase (ASNase). Although the initial remission rate is quite high, relapse and associated drug resistance remain a problem. In vitro studies have demonstrated an adaptive increase in asparagine synthetase (AS) expression in ASNase-resistant cells, which is believed to permit ASNase-resistant human leukaemia cells to survive in vivo. The present results, obtained with ASNase-sensitive and -resistant human MOLT-4 leukaemia cell lines, illustrate that several other adaptive processes occur to provide sufficient amounts of the AS substrates, aspartate and glutamine, required to support this increased enzymic activity. In both cell populations, aspartate is derived almost exclusively from intracellular sources, whereas the necessary glutamine arises from both intracellular and extracellular sources. Transport of glutamine into ASNase-resistant cells is significantly enhanced compared with the parental cells, whereas amino acid efflux (e.g. asparagine) is reduced. Most of the adaptive change for the amino acid transporters, Systems A, ASC and L, is rapidly (12 h) reversed following ASNase removal. The enzymic activity of glutamine synthetase is also enhanced in ASNase-resistant cells by a post-transcriptional mechanism. The results demonstrate that there are several sites of metabolic adaptation in ASNase-treated leukaemia cells that serve to promote the replenishment of both glutamine and asparagine. PMID:11485552

Aslanian, A M; Kilberg, M S

2001-08-15

413

Water Cycle  

NSDL National Science Digital Library

4th Grade Science - Water Cycle Water Cycle two day interactive lesson plan. DAY 1: Welcome to the Water Cycle! Today we are going to be exploring and finding out more about the wonderful Water Cycle! For starters we are going to start with a movie, click the following link and watch the video and ...

Staley, Mrs.

2009-11-09

414

Impact of heat processing on the detection of the major shellfish allergen tropomyosin in crustaceans and molluscs using specific monoclonal antibodies.  

PubMed

The major heat-stable shellfish allergen, tropomyosin, demonstrates immunological cross-reactivity, making specific differentiation of crustaceans and molluscs for food labelling very difficult. The aim of this study was to evaluate the application of allergen-specific monoclonal antibodies in differential detection of shellfish-derived tropomyosin in 11 crustacean and 7 mollusc species, and to study the impact of heating on its detection. Cross-reactive tropomyosin was detected in all crustacean species, with partial detection in molluscs: mussels, scallops and snails but none in oyster, octopus and squid. Furthermore, we have demonstrated that heating of shellfish has a profound effect on tropomyosin detection. This was evident by the enhanced recognition of multiple tropomyosin variants in the analysed shellfish species. Specific monoclonal antibodies, targetting the N-terminal region of tropomyosin, must therefore be developed to differentiate tropomyosins in crustaceans and molluscs. This can help in correct food labelling practices and thus protection of consumers. PMID:23993581

Kamath, Sandip D; Abdel Rahman, Anas M; Komoda, Toshikazu; Lopata, Andreas L

2013-07-03

415

Heterospecific transgenesis in Drosophila suggests that engrailed.a is regulated by POU proteins in the crustacean Sacculina carcini  

Microsoft Academic Search

Almost all knowledge of the regulation of segmentation genes in arthropods comes from Drosophila. In order to study the regulation of the segment-polarity gene engrailed in a non-insect arthropod we focussed on putative regulatory regions of the engrailed.a (en.a) gene in the barnacle crustacean Sacculina carcini. In this animal, en.a is expressed in segmental stripes like the engrailed genes of

Jean-Michel Gibert; Nicolas Joannin; Marylin Blin; Catherine Rigolot; Emmanuèle Mouchel-Vielh; Eric Quéinnec; Jean S. Deutsch

2002-01-01

416

Rapid Isolation of Nanogram Amounts of Crustacean Erythrophore Concentrating Hormone from Invertebrate Nerve Tissue by RP-HPLC  

Microsoft Academic Search

A reverse phase-high performance liquid chromatography (rp-hplc) method was developed for the rapid isolation of nanogram amounts of crustacean erythrophore concentrating hormone (CECH) from invertebrate nerve tissue. Tissue homogenates from the shrimp, Paleomenetes pugio, were subjected to a multistep work-up to remove proteins and lipids prior to analysis by rp-hplc. Samples were eluted with a concave gradient of 0.1% trifluoroacetic

Howard Jaffe; Marcia Loeb; Dora K. Hayes; Nancy Holston

1982-01-01

417

Seasonality and abundance of some dominant crustacean zooplankton in Lake Awasa, a tropical rift valley lake in Ethiopia  

Microsoft Academic Search

The zooplankton of a Rift Valley lake in Ethiopia, Awasa, was sampled at 3 stations for 2 years (1986 and 1987) concurrently\\u000a with various meteorological and limnological measurements. The spatial and temporal variation in abundance of some numerically\\u000a dominant crustaceans, Mesocyclops aequatorialis similis (Copepoda), Thermocyclops consimilis (Copepoda) and Diaphanosoma excisum (Cladocera) is discussed. Temporal (months, sampling dates) rather than spatial

Seyoum Mengestou; C. H. Fernando

1991-01-01

418

The Effect of Agro-Wastes and Crustacean Fillers on Poly (Vinyl-Acetate) Emulsion Wood Adhesives  

Microsoft Academic Search

Cellulosic and crustacean filler materials were used to study their effects on poly(vinyl-acetate) (PVAC) emulsion wood adhesives. The elastoplastic behavior of the filler-treated PVAC emulsion was studied using differential scanning calorimetry and dynamic mechanical thermal analysis. The result revealed that the glass transition temperature (Tg) of the filler-treated polymer is not significantly changed by the addition of the filler materials,

I. U. Ogban; O. Ogbobe

2008-01-01

419

Fishes and decapod crustaceans of Cape Cod eelgrass meadows: Species composition, seasonal abundance patterns and comparison with unvegetated substrates  

Microsoft Academic Search

Bimonthly trawl samples from eelgrass and nearby unvegetated areas on Cape Cod, Massachusetts, showed greater species richness\\u000a in eelgrass meadows relative to unvegetated areas, and greater summer abundance in vegetation for decapod crustaceans and\\u000a fishes. The composition of eelgrass-associated decapods and fishes was dominated by cold-water taxa and was strikingly different\\u000a from that of the better studied eelgrass meadows of

K. L. Heck; K. W. Able; M. P. Fahay; C. T. Roman

1989-01-01

420

Changes in the pelagic crustacean zooplankton of high-boreal Island Lake, Saskatchewan, associated with uranium mining  

Microsoft Academic Search

Island Lake, Saskatchewan, has become eutrophic, subsaline (salinity between 0.5 and 3.0 g I-1) and contaminated with several metals over the last decade. In this study, the crustacean zooplankton community in the lake in early summer 1989 is compared to the community during the early summers of the baseline years 1978 and 1979, based on archived environmental impact assessment samples.

G. E. Melville

1995-01-01

421

Day-night migrations by deep-sea decapod crustaceans in experimental samplings in the Western Mediterranean sea  

Microsoft Academic Search

Analysis of abundance and size frequency data on decapod crustacean species in two different habitats (inside and outside a submarine canyon) in the Western Mediterranean during two near-continuous 24-h sampling periods using commercial bottom trawls provided an indication of migratory ability and ac­ tivity of the numerically dominant species. Certain nektobenthic species (e.g. Aristeus antennatus) carried out migrations up the

J. E. Cartes; F. Sarda; J. Lleonart

1993-01-01

422

Crustacean communities as food resources for fish in shallow Polesie lakes with contrasting development of submerged macrophytes  

Microsoft Academic Search

The aim of the research was to evaluate crustacean forage resources for fish in five shallow lakes varied in respect to species richness and coverage of submerged macrophytes, and thus representing different alternative stable states. The results revealed that lakes with a high or moderate abundance of macrophytes and moderate visibility (macrophyte-dominated Lake Rotcze, phytoplankton-macrophyte dominated lakes Sumin and G??bokie)

Ma?gorzata Adamczuk; Ryszard Kornijów

2011-01-01

423

Limb development in a primitive crustacean, Triops longicaudatus : subdivision of the early limb bud gives rise to multibranched limbs  

Microsoft Academic Search

Recent advances in developmental genetics of Drosophila have uncovered some of the key molecules involved in the positioning and outgrowth of the leg primordia. Although expression\\u000a patterns of these molecules have been analyzed in several arthropod species, broad comparisons of mechanisms of limb development\\u000a among arthropods remain somewhat speculative since no detailed studies of limb development exist for crustaceans, the

T. A. Williams; Gerd B. Müller

1996-01-01

424

Role of crustacean hyperglycemic hormone (CHH) in the environmental stressor-exposed intertidal copepod Tigriopus japonicus.  

PubMed

To identify and characterize CHH (TJ-CHH) gene in the copepod Tigriopus japonicus, we analyzed the full-length cDNA sequence, genomic structure, and promoter region. The full-length TJ-CHH cDNA was 716bp in length, encoding 136 amino acid residues. The deduced amino acid sequences of TJ-CHH showed a high similarity of the CHH mature domain to other crustaceans. Six conserved cysteine residues and five conserved structural motifs in the CHH mature peptide domain were also observed. The genomic structure of the TJ-CHH gene contained three exons and two introns in its open reading frame (ORF), and several transcriptional elements were detected in the promoter region of the TJ-CHH gene. To investigate transcriptional change of TJ-CHH under environmental stress, T. japonicus were exposed to heat treatment, UV-B radiation, heavy metals, and water-accommodated fractions (WAFs) of Iranian crude oil. Upon heat stress, TJ-CHH transcripts were elevated at 30°C and 35°C for 96h in a time-course experiment. UV-B radiation led to a decreased pattern of the TJ-CHH transcript 48h and more after radiation (12kJ/m(2)). After exposure of a fixed dose (12kJ/m(2)) in a time-course experiment, TJ-CHH transcript was down-regulated in time-dependent manner with a lowest value at 12h. However, the TJ-CHH transcript level was increased in response to five heavy metal exposures for 96h. Also, the level of the TJ-CHH transcript was significantly up-regulated at 20% of WAFs after exposure to WAFs for 48h and then remarkably reduced in a dose-dependent manner. These findings suggest that the enhanced TJ-CHH transcript level is associated with a cellular stress response of the TJ-CHH gene as shown in decapod crustaceans. This study is also helpful for a better understanding of the detrimental effects of environmental changes on the CHH-triggered copepod metabolism. PMID:23797038

Kim, Bo-Mi; Jeong, Chang-Bum; Han, Jeonghoon; Kim, Il-Chan; Rhee, Jae-Sung; Lee, Jae-Seong

2013-06-21

425

The effects of temperature on peripheral neuronal function in eurythermal and stenothermal crustaceans.  

PubMed

To determine whether neuronal function in Antarctic crustaceans is adapted to the low and narrow range of temperatures at which these animals live, we have compared conduction velocities in the peripheral nervous systems of two temperate species, the decapod Carcinus maenas and the isopod Ligia oceanica, and two Antarctic species, the isopod Glyptonotus antarcticus and the amphipod Paraceradocus gibber. Neuronal conduction velocity differs among the species in the order C. maenas > G. antarcticus > P. gibber > L. oceanica. When measured at the normal environmental temperatures characteristic of each species, conduction velocity of the Antarctic peracarid P. gibber is greater than that of its similar sized temperate relative L. oceanica, demonstrating complete thermal compensation. The temperate decapod C. maenas has a higher thermal dependence of neuronal conduction velocity than either of the Antarctic species, G. antarcticus and P. gibber, but the temperate L. oceanica does not. These data, when collated with published values, indicate that peracarid crustaceans (L. oceanica, G. antarcticus and P. gibber) have lower neuronal conduction velocities and a lower thermal dependence of neuronal conduction velocity than do other arthropods, irrespective of habitat. There is a linear dependence of conduction velocity on temperature down to -1.8 degrees C in all three species. Our data extend by more than 10 degrees the lower range of temperatures at which conduction velocities have been tested systematically in previous studies. The upper thermal block of neuronal conduction is similar in C. maenas, G. antarcticus, P. gibber and L. oceanica at 24.5, 19.5, 21.5 and 19.5 degrees C, respectively. This suggests that failure to conduct action potentials is not what determines the mortality of Antarctic invertebrates at approximately 10 degrees C. The excitability of axons in the leg nerve of G. antarcticus is not affected by temperatures ranging from -1.8 to +18 degrees C. The responses of sensory neurones activated by movements of spines on the leg, however, are strongly modulated by temperature, with maximal responses at 5-10 degrees C; well above the normal environmental temperature range for the species. The responses fail at 20-22 degrees C. The number of large diameter axons (which produce the fast action potentials recorded in this study) is the same in L. oceanica and G. antarcticus, but the median axon diameter is greater in L. oceanica than G. antarcticus. In G. antarcticus, however, there are glial wrappings around some large (>5 microm diameter) axons that may increase their conduction velocity. Such wrappings are not found in L. oceanica. PMID:16651562

Young, John S; Peck, Lloyd S; Matheson, Thomas

2006-05-01

426

Neuroendocrine regulation of osmoregulation and the evolution of air-breathing in decapod crustaceans.  

PubMed

Gills are the primary organ for salt transport, but in land crabs they are removed from water and thus ion exchanges, as well as CO(2) and ammonia excretion, are compromised. Urinary salt loss is minimised in land crabs by redirecting the urine across the gills where salt reabsorption occurs. Euryhaline marine crabs utilise apical membrane branchial Na(+)/H(+) and Cl(-)/HCO(3)(-) exchange powered by a basal membrane Na(+)/K(+)-ATPase, but in freshwater crustaceans an apical V-ATPase provides for electrogenic uptake of Cl(-) in exchange for HCO(3)(-). The HCO(3)(-) is provided by carbonic anhydrase facilitating CO(2) excretion while NH(4)(+) can substitute for K(+) in the basal ATPase and for H(+) in the apical exchange. Gecarcinid land crabs and the terrestrial anomuran Birgus latro can lower the NaCl concentration of the urine to 5 % of that of the haemolymph as it passes across the gills. This provides a filtration-reabsorption system analogous to the vertebrate kidney. Crabs exercise hormonal control over branchial transport processes. Aquatic hyper-regulators release neuroamines from the pericardial organs, including dopamine and 5-hydroxytryptamine (5-HT), which via a cAMP-mediated phosphorylation stimulate Na(+)/K(+)-ATPase activity and NaCl uptake. Freshwater species utilise a V-ATPase, and additional mechanisms of control have been suggested. Crustacean hyperglycaemic hormone (CHH) has now also been confirmed to have effects on hydromineral regulation, and a putative role for neuropeptides in salt and water balance suggests that current models for salt regulation are probably incomplete. In a terrestrial crabs there may be controls on both active uptake and diffusive loss. The land crab Gecarcoidea natalis drinking saline water for 3 weeks reduced net branchial Na(+) uptake but not Na(+)/K(+)-ATPase activity, thus implying a reduction in diffusive Na(+) loss. Further, in G. natalis Na(+) uptake and Na(+)/K(+)-ATPase were stimulated by 5-HT independently of cAMP. Conversely, in the anomuran B. latro, branchial Na(+) and Cl(-) uptake and Na(+)/K(+)-ATPase are inhibited by dopamine, mediated by cAMP. There has been a multiple evolution of a kidney-type system in terrestrial crabs capable of managing salt, CO(2) and NH(3) movements. PMID:11171421

Morris, S

2001-03-01

427

From genes to behavior: investigations of neurochemical signaling come of age for the model crustacean Daphnia pulex.  

PubMed

The cladoceran crustacean Daphnia pulex has served as a standard organism for aquatic toxicity testing for decades. The model organism status of D. pulex rests largely on its remarkable ability to rapidly adapt morphologically, physiologically and behaviorally to a wide range of environmental challenges, as well as on its parthenogenetic reproduction and ease of laboratory culture. As in all multicellular organisms, neurochemical control systems are undoubtedly major contributors to the functional flexibility of Daphnia. Surprisingly, little work has focused on understanding its neurochemistry at any level. Recently, D. pulex has been the subject of extensive genome and transcriptome sequencing, and it is currently the only crustacean with a fully sequenced, publicly accessible genome. Although the molecular work was initiated for gene-based investigations of ecotoxicology and toxicogenomics, the data generated have allowed for investigations into numerous aspects of Daphnia biology, including its neurochemical signaling. This Commentary summarizes our knowledge of D. pulex neurochemistry obtained from recent genomic and transcriptomic studies, and places these data in context with other anatomical, biochemical and physiological experiments using D. pulex and its sister species Daphnia magna. Suggestions as to how the Daphnia molecular data may be useful for future investigations of crustacean neurochemical signaling are also provided. PMID:22786629

Christie, Andrew E; McCoole, Matthew D

2012-08-01

428

Muscle water control in crustaceans and fishes as a function of habitat, osmoregulatory capacity, and degree of euryhalinity.  

PubMed

This study aimed at detecting possible patterns in the relationship between Anisosmotic Extracellular Regulation (AER) and Isosmotic Intracellular Regulation (IIR) in crustaceans and teleost fish from different habitats and evolutionary histories in fresh water (FW), thus different osmoregulatory capabilities, and degrees of euryhalinity. Crustaceans used were the hololimnetic FW Aegla schmitti, and Macrobrachium potiuna, the diadromous FW Macrobrachium acanthurus, the estuarine Palaemon pandaliformis and the marine Hepatus pudibundus; fishes used were the FW Corydoras ehrhardti, Mimagoniates microlepis, and Geophagus brasiliensis, and the marine-estuarine Diapterus auratus. The capacity for IIR was assessed in vitro following wet weight changes of isolated muscle slices incubated in anisosmotic saline (~50% change). M. potiuna was the crustacean with the highest capacity for IIR; the euryhaline perciforms G. brasiliensis and D. auratus displayed total capacity for IIR. It is proposed that a high capacity for IIR is required for invading a new habitat, but that it is later lost after a long time of evolution in a stable habitat, such as in the FW anomuran crab A. schmitti, and the Ostariophysian fishes C. ehrhardti and M. microlepis. More recent FW invaders such as the palaemonid shrimps (M. potiuna and M. acanthurus) and the cichlid G. brasiliensis are euryhaline and still display a high capacity for IIR. PMID:18325804

Freire, Carolina A; Amado, Enelise M; Souza, Luciana R; Veiga, Marcos P T; Vitule, Jean R S; Souza, Marta M; Prodocimo, Viviane

2008-02-11

429

Selected endocrine disrupting compounds (Vinclozolin, Flutamide, Ketoconazole and Dicofol): Effects on survival, occurrence of males, growth, molting and reproduction of Daphnia magna  

Microsoft Academic Search

Background, Aim and Scope  Pollution-induced endocrine disruption in vertebrates and invertebrates is a worldwide environmental problem, but relatively\\u000a little is known about effects of endocrine disrupting compounds (EDCs) in planktonic crustaceans (including Daphnia magna). Aims of the present study were to investigate acute 48 h toxicity and sub-chronic (4–6 days) and chronic (21 days) effects\\u000a of selected EDCs in D. magna.

Maher H. Haeba; Klára Hilscherová; Edita Mazurová; Ludek Bláha

2008-01-01

430

Effects of vitamins, probiotics, and protein level on semen traits and some seminal plasma macro- and microminerals of male broiler breeders after zinc-induced molting.  

PubMed

This study was conducted to investigate the effects of vitamin E, vitamin C, probiotics, dietary protein level, and their combination on semen traits and seminal plasma macro- and microminerals in 65-week-old male broiler breeders after zinc-induced molting. One hundred eighty birds were induced to molt by mixing zinc oxide (3,000 mg/kg) in the diet. The birds were divided into six groups (five replicates) by completely randomized design. One group was kept as control (16% CP), while the other five were supplemented with vitamin E (100 IU/kg feed), vitamin C (500 IU/kg feed) probiotics (50 mg/L), protein level (14% CP), and their combination. Semen samples were weekly collected for determination of semen volume, sperm concentration, motility, and dead sperm percentage. Analyses of Na, K, Ca and Mg, Zn, Fe, Mn, and Cu in seminal plasma were also performed. Overall, mean semen volume was significantly high in vitamin E and C supplemented groups compared to control. Overall mean sperm motility was significantly higher in vitamin E supplemented group, whereas dead sperm percentage was significantly lower in the vitamin C group compared to control. Mineral analyses revealed that overall mean seminal plasma Mg increased significantly in vitamin E and C supplemented groups compared to control. Similarly, significantly high overall mean seminal plasma Cu concentration was observed in vitamins E and C and combination groups. It can be concluded that vitamins have a vital role in improving semen quality and bioavailability of Mg and Cu in seminal plasma of the post-molt cockerels. PMID:22318702

Khan, Rifat Ullah; Zia-Ur-Rahman; Javed, Ijaz; Muhammad, Faqir

2012-02-09

431

The Life Cycle of the Antarctic Nematode Plectus murrayi Under Laboratory Conditions  

PubMed Central

We study and describe the life cycle of Plectus murrayi, a free-living, bacterivorous soil nematode endemic to terrestrial Antarctica. The study was performed at 15°C, a temperature identified as optimal for growth rate studies in the laboratory. Under these conditions, we observed that the first molt occurs in the egg, and second-stage juveniles hatch 12 to 14 d after egg laying. Individuals undergo three subsequent molts to become adults 23 to 26 d after hatching with a final average length of 950 ?m. Egg-laying begins 41 to 43 d after hatching, resulting in an egg-to-egg life cycle ranging from 53 to 57 d under our experimental conditions. Considering that the average soil temperature during austral summers in the McMurdo Dry Valleys is only a few degrees above freezing, it is highly likely that many, if not most of these animals, require more than 1 yr to complete their entire life cycle. Our study supports other research that establishes P. murrayi as an important model organism for studying adaptation to extreme environmental stress.

de Tomasel, Cecilia Milano; Adams, Byron J.; Tomasel, Fernando G.; Wall, Diana H.

2013-01-01

432

The Life Cycle of the Antarctic Nematode Plectus murrayi Under Laboratory Conditions.  

PubMed

We study and describe the life cycle of Plectus murrayi, a free-living, bacterivorous soil nematode endemic to terrestrial Antarctica. The study was performed at 15°C, a temperature identified as optimal for growth rate studies in the laboratory. Under these conditions, we observed that the first molt occurs in the egg, and second-stage juveniles hatch 12 to 14 d after egg laying. Individuals undergo three subsequent molts to become adults 23 to 26 d after hatching with a final average length of 950 ?m. Egg-laying begins 41 to 43 d after hatching, resulting in an egg-to-egg life cycle ranging from 53 to 57 d under our experimental conditions. Considering that the average soil temperature during austral summers in the McMurdo Dry Valleys is only a few degrees above freezing, it is highly likely that many, if not most of these animals, require more than 1 yr to complete their entire life cycle. Our study supports other research that establishes P. murrayi as an important model organism for studying adaptation to extreme environmental stress. PMID:23589658

de Tomasel, Cecilia Milano; Adams, Byron J; Tomasel, Fernando G; Wall, Diana H

2013-03-01

433

Expression of annual cycles in preen wax composition in red knots: constraints on the changing phenotype.  

PubMed

Birds living in seasonal environments change physiology and behavior in correspondence to temporally changing environmental supplies, demands and opportunities. We recently reported that the chemical composition of uropygial gland secretions of sandpipers (Scolopacidae, order Charadriformes) changes during the breeding season from mixtures of monoesters to diesters, which fulfill specific functions related to incubation. A proper temporal match between the expression of diester preen waxes and incubation requires a flexible organization of the trait. Here we analyze the possible degrees of flexibility with reference to the functionality of better-understood molt and body mass cycles of free-living and captive red knots (Calidris canutus). The relative flexibility of seasonal cycles in preen wax composition was examined by two experimental perturbations: (1) giving birds restricted access to food and (2) monitoring them long-term under a constant photoperiodic regime. We found that wax type cannot change instantaneously, but that changing the type of wax is under similar organizational time constraints as the replacement of feathers. Just as molt and mass cycles, the seasonal rhythm of diester secretion appeared to be under endogenous control: most birds placed in a constant photoperiod still maintained seasonally changing preen waxes. Diester preen wax secretion was synchronized with the peak in body mass in spring, but became less well expressed under constant photoperiodic conditions and when food availability was limited. PMID:17397066

Reneerkens, Jeroen; Piersma, Theunis; Damsté, Jaap S Sinninghe

2007-03-01

434

The IMP dehydrogenase inhibitor mycophenolic acid antagonizes the CTP synthetase inhibitor 3-deazauridine in MOLT-3 human leukemia cells: a central role for phosphoribosyl pyrophosphate.  

PubMed

Mycophenolic acid, an inhibitor of the enzyme IMP dehydrogenase, antagonizes the CTP synthetase inhibitor 3-deazauridine in its anti-proliferative effects on MOLT-3 human T leukemia cells. No depletion of CTP occurred, and decreased amounts of 3-deazuridine-triphosphate were measured in cells incubated with mycophenolic acid and 3-deazuridine. Most probably, these phenomena are related to the increased amounts of PRPP observed, which can result in an increased pyrimidine biosynthesis de novo and, as a consequence, a decreased metabolism of 3-deazauridine via the salvage pathway. PMID:7575666

van Berg, A A; Mooyer, P A; van Lenthe, H; Stet, E H; De Abreu, R A; van Kuilenburg, A B; van Gennip, A H

1995-09-28