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1

Proteomics and signal transduction in the crustacean molting gland  

Microsoft Academic Search

Synopsis Regulation of the molting cycle in decapod crustaceans involves 2 endocrine organs: the X-organ\\/sinus gland (XO\\/SG) complex located in the eyestalk ganglia and the Y-organ (YO) located in the cephalothorax. Two neuropeptides (molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH)) are produced in the XO\\/SG complex and inhibit ecdysteroidogenesis in the YO. Thus, YO activation is induced by eyestalk

Sung Gu Lee; Donald L. Mykles

2006-01-01

2

What is Molt-Inhibiting Hormone? The Role of an Ecdysteroidogenesis Inhibitor in the Crustacean Molting Cycle  

Microsoft Academic Search

The in vivo molt-inhibitory effects of the ecdysone biosynthesis inhibitors 3-hydroxy-L-kynurenine and xanthurenic acid were investigated. These ecdysone biosynthesis inhibitors, isolated from the eyestalks of blue crabs (Callinectes sapidus), were injected into eyestalk-ablated crayfish (Procambarus clarkii). The active factor was found to be species-nonspecific within crabs and crayfish. The seasonal profiles of the xanthurenic acid and ecdysone titers exhibited a

Yoko Naya; Mayumi Ohnishi; Midori Ikeda; Wataru Miki; Koji Nakanishi

1989-01-01

3

Endogenous xanthurenic acid as a regulator of the crustacean molt cycle  

Microsoft Academic Search

By means of in vitro assay, it has been demonstrated that xanthurenic acid, a metabolite of 3-hydroxy-L-kynurenine which is contained in crustacean eyestalks (X-organ), acts as an inhibitor of ecdysteroidogenesis in Y-organs. Xanthurenic acid directly prevents an oxygenase (probably cytochrome P-450 mediated) from acting on ecdysone precursor(s). Injection with physiological doses of 3-hydroxy-L-kynurenine in saline delayed the onset of induced

Y. Naya; W. Miki; M. Ohnishi; K. Nakanishi

1989-01-01

4

Proteomics and signal transduction in the crustacean molting gland.  

PubMed

Regulation of the molting cycle in decapod crustaceans involves 2 endocrine organs: the X-organ/sinus gland (XO/SG) complex located in the eyestalk ganglia and the Y-organ (YO) located in the cephalothorax. Two neuropeptides [molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH)] are produced in the XO/SG complex and inhibit ecdysteroidogenesis in the YO. Thus, YO activation is induced by eyestalk ablation (ESA), which removes the primary source of MIH and CHH. Cyclic nucleotides (cAMP and cGMP) and nitric oxide (NO) appear to mediate neuropeptide suppression of the YO. Proteomics was used to identify potential components of signal transduction pathways ("targeted" or cell-map proteomics) as well as assess the magnitude of protein changes in response to activation ("global" or expression proteomics) in the tropical land crab, Gecarcinus lateralis. Total proteins in YOs from intact and ES-ablated animals were separated by two-dimensional gel electrophoresis and expression profiles were assessed by image analysis and gene clustering software. ESA caused a >3-fold increase in the levels of 170 proteins and >3-fold decrease in the levels of 89 proteins; a total of 543 proteins were quantified in total YO extracts. ESA induced significant changes in the levels of 3 groups of proteins eluting from a phosphoprotein column and detected with phosphoprotein staining of two-dimensional gels; ?17 kDa and ?150 kDa phosphoproteins increased in activated YOs, while ?12 kDa phosphoproteins decreased. A ?150 kDa phosphoprotein, which was isolated only from activated YO, was identified as NO synthase by western blotting and mass spectrometry of trypsin peptides. These data show that phosphorylation of NO synthase is associated with activation of the YO. A neuropeptide signaling pathway involving NO synthase and NO-sensitive guanylyl cyclase is proposed. PMID:21672800

Lee, Sung Gu; Mykles, Donald L

2006-12-01

5

Characterization of Limb Autotomy Factor Proecdysis (LAFpro), Isolated From Limb Regenerates, That Suspends Molting in the Land Crab Gecarcinus lateralis  

Microsoft Academic Search

Molting and limb regeneration are tightly cou- pled processes, both of which are regulated by ecdysteroid hormone synthesized and secreted by the Y-organs. Regen- eration of lost appendages can affect the timing and duration of the proecdysial, or premolt, stage of the molt cycle. Autotomy of all eight walking legs induces precocious molts in various decapod crustacean species. In the

XIAOLI YU; ERNEST S. CHANG; DONALD L. MYKLES

6

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

7

MOLT-RELATED SUSCEPTIBILITY AND REGENERATIVE LIMB GROWTH AS SENSITIVE INDICATORS OF AQUATIC POLLUTANT TOXICITY TO CRUSTACEANS  

EPA Science Inventory

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 dril...

8

The ultrastructure of the oenocytes in the molt/intermolt cycle of an insect.  

PubMed

The structure and development of the permanent oenocytes of Calpodes ethlius (Lepidoptera, Hesperiidae) are described. There are three sorts of oenocyte. The permanent oenocytes are arranged ventral to the last two pairs of spiracles on abdominal segments 7 and 8 in four clusters of about 45 cells each. The molt cycle oenocytes are ventral to the other spiracles and only enlarge at molting. The subdermal oenocytes differentiate from the epidermis in large numbers shortly before pupation. The permanent oenocytes are large polyploid cells characterized by a cytoplasm of densely packed smooth tubular endoplasmic reticulum, and a plasma membrane invaginated in a meshwork of tubes ending in a reticular layer about 12 micro below the surface. There are two sorts of Golgi complex, one small and of conventional form, the other composed of clouds of microvesicles. 'Dense bodies', believed to belong to the microbody class of organelles, arise directly from the STER. There is a variety of membranous and 'crystalline' inclusions. The formation of isolation membranes from the tubular endoplasmic reticulum, and the origin of isolation bodies and autophagic vacuoles are described. Some autophagy takes place at all times in the molt/intermolt cycle, but there are phases of massive autophagy before the 4th-5th molt and the 5th-pupal molt. These phases coincide with pinocytosis of blood proteins and overlap with or are followed by phases of nuclear replication, RNA synthesis (ribosomes) and ER regeneration. Nuclear blebbing occurs before pupation. The morphology of the oenocytes is most like that of vertebrate cells engaged in steroid hormone synthesis. It is pointed out that the oenocytes rather than the prothoracic glands could be the source of ecdysone and the stimulus for molting. PMID:18631462

Locke, M

1969-01-01

9

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

10

Variation in lipid classes during the molting cycle of the prawn Penaeus japonicus  

Microsoft Academic Search

The variation in the concentration and fatty acid composition of lipid classes during the molting cycle of the prawn Penaeus japonicus was investigated. The lipid concentration of the whole body reached a maximum at mid-premolt (Stage D2) and then decreased to low level at late premolt (Stage D3–4). The accumulation of lipids during the premolt period seemed to be attributable

S. Teshima; A. Kanazawa; H. Okamoto

1977-01-01

11

Molt cycle regulation of protein synthesis in skeletal muscle of the blackback land crab, Gecarcinus lateralis, and the differential expression of a myostatin-like factor during atrophy induced by molting or unweighting.  

PubMed

In decapod crustaceans, claw muscle undergoes atrophy in response to elevated ecdysteroids while thoracic muscle undergoes atrophy in response to unweighting. The signaling pathways that regulate muscle atrophy in crustaceans are largely unknown. Myostatin is a negative regulator of muscle growth in mammals, and a myostatin-like cDNA is preferentially expressed in muscle of the land crab, Gecarcinus lateralis (Gl-Mstn). Contrary to prediction, levels of Gl-Mstn mRNA decreased dramatically in both the claw closer and weighted thoracic muscles when molting was induced by either eyestalk ablation (ESA) or multiple limb autotomy (MLA). However, the effect of molt induction was greater in the claw muscle. By late premolt, Gl-Mstn mRNA in the claw muscle decreased 81% and 94% in ESA and MLA animals, respectively, and was negatively correlated with ecdysteroids. Gl-Mstn mRNA in thoracic muscle decreased 68% and 82% in ESA and MLA animals, respectively, but was only weakly correlated with ecdysteroid. Claw and thoracic muscles also differed to varying extents in the expression of ecdysteroid receptor (Gl-EcR and Gl-RXR), elongation factor-2 (Gl-EF-2), and calpain T (Gl-CalpT) in response to molt induction, but levels of the four transcripts were not correlated with ecdysteroid. The downregulation of Gl-Mstn expression in premolt claw muscle coincided with 11- and 13-fold increases in protein synthesis in the myofibrillar and soluble protein fractions, respectively. Furthermore, the rate of the increase in the synthesis of soluble proteins was greater than that of myofibrillar proteins during early premolt (1.4:1, soluble:myofibrillar), but the two were equivalent during late premolt. By contrast, Gl-Mstn mRNA increased 3-fold and Gl-CalpT mRNA decreased 40% in unweighted thoracic muscle; there was little or no effect on Gl-EF-2, Gl-EcR, and Gl-RXR mRNA levels. These data indicate that Gl-Mstn expression is negatively regulated by both ecdysteroids and load-bearing contractile activity. The downregulation of Gl-Mstn in claw muscle may induce the elevated protein turnover associated with remodeling of the contractile apparatus during molt-induced atrophy. The upregulation of Gl-Mstn in unweighted thoracic muscle suggests that this factor is also involved in disuse atrophy when hemolymph ecdysteroid levels are low. PMID:20008374

Covi, J A; Bader, B D; Chang, E S; Mykles, D L

2010-01-01

12

Characterization of limb autotomy factor-proecdysis (LAF(pro)), isolated from limb regenerates, that suspends molting in the land crab Gecarcinus lateralis.  

PubMed

Molting and limb regeneration are tightly coupled processes, both of which are regulated by ecdysteroid hormone synthesized and secreted by the Y-organs. Regeneration of lost appendages can affect the timing and duration of the proecdysial, or premolt, stage of the molt cycle. Autotomy of all eight walking legs induces precocious molts in various decapod crustacean species. In the land crab Gecarcinus lateralis, autotomy of a partially regenerated limb bud before a critical period during proecdysis (regeneration index <17) delays molting so that a secondary limb bud (2 degrees LB) forms and the animal molts with a complete set of walking legs. It is hypothesized that 2 degrees LBs secrete a factor, termed limb autotomy factor-proecdysis (LAF(pro)), that inhibits molting by suppressing the Y-organs from secreting ecdysone. Molting was induced by autotomy of eight walking legs; autotomy of primary (1 degrees ) LBs reduced the level of ecdysteroid hormone in the hemolymph 73% by one week after limb bud autotomy (LBA). Injection of extracts from 2 degrees LBs, but not 1 degrees LBs, inhibited 1 degrees LB growth in proecdysial animals, thus having the same effect on molting as LBA. The inhibitory activity in 2 degrees LB extracts was stable after boiling in water for 15 min, but was destroyed by boiling 15 min in 0.1 N acetic acid or incubation with proteinase K. These results support the hypothesis that LAF(pro) is a peptide that resembles a molt-inhibiting hormone. PMID:12086991

Yu, Xiaoli; Chang, Ernest S; Mykles, Donald L

2002-06-01

13

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

14

Larval development of Lynceus brachyurus (Crustacea, Branchiopoda, Laevicaudata): redescription of unusual crustacean nauplii, with special attention to the molt between last nauplius and first juvenile.  

PubMed

The larval development of "conchostracans" has received only scattered attention. Here I present the results of a study on the larval (naupliar) development and the metamorphosis of Lynceus brachyurus, a member of the bivalved branchiopod order the Laevicaudata. Lynceus brachyurus is the only species of the "Conchostraca" in Denmark. The phylogenetic position of the Laevicaudata has traditionally been a source of controversy, and this study does not solve the question completely. This work focuses on features potentially important for phylogeny. The general appearance of the larvae of L. brachyurus has been known for more than a century and a half, and some of its unique features include a large, larval dorsal shield; a huge, plate-like labrum; and a pair of immovable, horn-like antennules. However, many details relating to limb morphology, potentially important for phylogeny, have not been studied previously. Based on size categories, five or six larval stages can be recognized. The larvae approximately double their length and width during development (length: 230-520 microm). Most morphological features stay largely unchanged during development, but the antennal coxal masticatory spines are significant exceptions: they become bifid after one of the first molts. In all larval stages only the antennae and the mandibles actively move. In late naupliar stages the trunk limbs become visible as rows of laterally placed, undeveloped, and still immovable lobes. Swimming is performed by the antennae, whereas the mandibles appear to be involved mainly in feeding, as in other branchiopod larvae. The last naupliar stage undergoes a small metamorphosis to the first juvenile stage, the details of which in part were studied by following the premolt juvenile condition through the cuticle of the last stage nauplius. Among other changes there is a characteristic change in the shape and morphology of the univalved dorsal naupliar shield to a bivalved juvenile carapace. The general morphologies of the antennae and the mandibles are very similar to those of other branchiopod larvae and fall well within the "branchiopod naupliar feeding apparatus" recognized as a branchiopod synapomorphy by Olesen (2003), but some specific features shared with the larvae of other "conchostracans" are also identified. These special "conchostracan" features include: 1) a similar antennular setation; 2) a similar comb-like setulation of the bifid antennal coxal processes; and 3) mandibular palpsetae with setules condensed. In light of recent suggestions concerning branchiopod phylogeny (Cyclestheria as a sister group to the Cladocera), these similarities probably do not support a monophyletic "Conchostraca" but rather are symplesiomorphies of this taxon. A final decision must await a phylogenetic analysis of a more complete set of characters. PMID:15549720

Olesen, Jørgen

2005-05-01

15

Molt cycle-dependent molecular chaperone and polyubiquitin gene expression in lobster  

PubMed Central

Lobster claw muscle undergoes atrophy in correlation with increasing ecdysteroid (steroid molting hormone) titers during premolt. In vivo molecular chaperone (constitutive heat shock protein 70 [Hsc70], heat shock protein 70 [Hsp70], and Hsp90) and polyubiquitin messenger ribonucleic acid (mRNA) levels were examined in claw and abdominal muscles from individual premolt or intermolt lobsters. Polyubiquitin gene expression was assayed as a marker for muscle atrophy. Both Hsc70 and Hsp90 mRNA levels were significantly induced in premolt relative to intermolt lobster claw muscle, whereas Hsp70 mRNA levels were not. Hsp90 gene expression was significantly higher in premolt claw muscle when compared with abdominal muscle. Polyubiquitin mRNA levels were elevated in premolt when compared with intermolt claw muscle and significantly elevated relative to premolt abdominal muscle.

Spees, Jeffrey L.; Chang, Sharon A.; Mykles, Donald L.; Snyder, Mark J.; Chang, Ernest S.

2003-01-01

16

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

17

Molecular characterization of a cDNA encoding red pigment-concentrating hormone in black tiger shrimp Penaeus monodon: Implication of its function in molt and osmoregulation.  

PubMed

Red pigment-concentrating hormone (RPCH) is a member of the AKH/RPCH peptide family present mainly in crustaceans and insects. Insect AKH is responsible for metabolic functions whereas RPCH plays a major role in the aggregation of red chromatophores in crustaceans. In this study, a full-length cDNA of RPCH of the black tiger shrimp, Penaeus monodon (PmRPCH) was cloned by Rapid Amplification of cDNA Ends strategies from the eyestalk RNA. A 770bp full-length PmRPCH cDNA harbored 279bp of an open reading frame encoding a signal peptide of 21 amino acid residues, an 8 amino acid mature RPCH peptide, followed by 61 amino acid residues of a RPCH precursor-related peptide. The highest levels of PmRPCH mRNA expression were detected in eyestalks while lower expression was found in other nervous tissues i.e. brain, thoracic ganglia and abdominal nerve cord. Expression of PmRPCH was transiently stimulated upon hypersalinity change within 12h suggesting its osmoregulatory function. During the molting cycle, PmRPCH in the eyestalk was expressed at the lowest level in the early pre-molt stage (D0), then gradually increased over the pre-molt period and reached the highest level in the late pre-molt (D4) and post-molt (AB) stages. RPCH peptide at a dose of 100pmol also increased gill Na(+)/K(+) ATPase activity in 36-48h after injection. However, PmRPCH did not accelerate the duration of molting cycle. Our results provide the first evidence on the potential function of PmRPCH in molting, probably by mediating hemolymph osmolality and ion transport enzymes during the late pre-molt stage. PMID:24937259

Sathapondecha, Ponsit; Panyim, Sakol; Udomkit, Apinunt

2014-09-01

18

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

19

Myostatin from the American lobster, Homarus americanus: Cloning and effects of molting on expression in skeletal muscles.  

PubMed

A cDNA encoding a myostatin (Mstn)-like gene from an astacuran crustacean, Homarus americanus, was cloned and characterized. Mstn inhibits skeletal muscle growth in vertebrates and may play a role in crustacean muscle as a suppressor of protein synthesis. Sequence analysis and three-dimensional modeling of the Ha-Mstn protein predicted a high degree of conservation with vertebrate and other invertebrate myostatins. Qualitative polymerase chain reaction (PCR) demonstrated ubiquitous expression of transcript in all tissues, including skeletal muscles. Quantitative PCR analysis was used to determine the effects of natural molting and eyestalk ablation (ESA) on Ha-Mstn expression in the cutter claw (CT) and crusher claw (CR) closer muscles and deep abdominal (DA) muscle. In intermolt lobsters, the Ha-Mstn mRNA level in the DA muscle was significantly lower than the mRNA levels in the CT and CR muscles. Spontaneous molting decreased Ha-Mstn mRNA during premolt, with the CR muscle, which is composed of slow-twitch (S?) fibers, responding preferentially (82% decrease) to the atrophic signal compared to fast fibers in CT (51% decrease) and DA (69% decrease) muscles. However, acute increases in circulating ecdysteroids caused by ESA had no effect on Ha-Mstn mRNA levels in the three muscles. These data indicate that the transcription of Ha-Mstn is differentially regulated during the natural molt cycle and it is an important regulator of protein turnover in molt-induced claw muscle atrophy. PMID:20696264

MacLea, Kyle S; Covi, Joseph A; Kim, Hyun-Woo; Chao, Erica; Medler, Scott; Chang, Ernest S; Mykles, Donald L

2010-12-01

20

Crustacean Muscles: Atrophy and Regeneration During Molting.  

National Technical Information Service (NTIS)

The ultrastructural basis of atrophy of claw closer muscle of the land crab and the organization of myofibrils and sacroplasmic reticulum during the hydrolysis of protein that occurs during proecdysis was examined. The changes that occur in contractile pr...

D. L. Mykles D. M. Skinner

1981-01-01

21

Switching skeletons: hydrostatic support in molting crabs  

NASA Technical Reports Server (NTRS)

Skeletal support systems are essential for support, movement, muscular antagonism, and locomotion. Crustaceans shed their rigid exoskeleton at each molt yet are still capable of forceful movement. We hypothesize that the soft water-inflated body of newly molted crabs may rely on a hydrostatic skeleton, similar to that of worms and polyps. We measured internal hydrostatic pressure and the force exerted during claw adduction and observed a strong correlation between force and hydrostatic pressure, consistent with hydrostatic skeletal support. This alternation between the two basic skeletal types may be widespread among arthropods.

Taylor, Jennifer R A.; Kier, William M.; Walker, I. D. (Principal Investigator)

2003-01-01

22

Characterization of the putative farnesoic acid O-methyltransferase (LvFAMeT) cDNA from white shrimp, Litopenaeus vannamei: Evidence for its role in molting.  

PubMed

Methyl farnesoate (MF) is the crustacean homolog of the insect juvenile hormone and is believed to regulate growth and reproduction in crustaceans. Farnesoic acid O-methyltransferase (FAMeT) catalyzes the conversion of farnesoic acid (FA) to MF. Here we report the cloning and characterization of two forms of FAMeTs (i.e. LvFAMeT-S and LvFAMeT-L) from the shrimp Litopenaeus vannamei. LvFAMeT transcript has a wide tissue distribution pattern in L. vannamei and is also expressed in nauplius, zoea, mysis, post-larval stages and adults. Unlike FAMeTs reported in other decapods, transcripts of two different sizes were detected in L. vannamei. We postulate that the wide distribution of LvFAMeT expression may be related to its role in growth and regulation of molting. To study the functions of LvFAMeT in molting, the RNA interference (RNAi) technique was used. Injection of double stranded RNA (dsRNA) for LvFAMeT knocked down the expression of LvFAMeT in shrimp for at least 3 days and the shrimp did not advance to the final stage of molt cycle. Furthermore, the expression of the molt-related genes encoding cathepsin-L and the hemocyanin gene was disturbed. Subsequently, 100% mortality of the shrimp was observed in the LvFAMeT dsRNA-injected shrimp. In contrast, control shrimp completed their molt and proceeded to the next molt cycle. We postulate that, as an important enzyme for the conversion of FA to MF, RNAi injection knocked down the expression of LvFAMeT which could potentially result in a decrease in the production of MF and subsequently, could affect the molting process. The newly identified LvFAMeT may be involved in the control of molting in shrimp. The results of this study demonstrate the potential use of the RNA interference technique to study other putative genes identified in crustaceans. PMID:18226425

Hui, Jerome Ho Lam; Tobe, Stephen S; Chan, Siu-Ming

2008-02-01

23

Differential expression profiling of components associated with exoskeletal hardening in crustaceans  

PubMed Central

Background Exoskeletal hardening in crustaceans can be attributed to mineralization and sclerotization of the organic matrix. Glycoproteins have been implicated in the calcification process of many matrices. Sclerotization, on the other hand, is catalysed by phenoloxidases, which also play a role in melanization and the immunological response in arthropods. Custom cDNA microarrays from Portunus pelagicus were used to identify genes possibly associated with the activation pathways involved in these processes. Results Two genes potentially involved in the recognition of glycosylation, the C-type lectin receptor and the mannose-binding protein, were found to display molt cycle-related differential expression profiles. C-type lectin receptor up-regulation was found to coincide with periods associated with new uncalcified cuticle formation, while the up-regulation of mannose-binding protein occurred only in the post-molt stage, during which calcification takes place, implicating both in the regulation of calcification. Genes presumed to be involved in the phenoloxidase activation pathway that facilitates sclerotization also displayed molt cycle-related differential expression profiles. Members of the serine protease superfamily, trypsin-like and chymotrypsin-like, were up-regulated in the intermolt stage when compared to post-molt, while trypsin-like was also up-regulated in pre-molt compared to ecdysis. Additionally, up-regulation in pre- and intermolt stages was observed by transcripts encoding other phenoloxidase activators including the putative antibacterial protein carcinin-like, and clotting protein precursor-like. Furthermore, hemocyanin, itself with phenoloxidase activity, displayed an identical expression pattern to that of the phenoloxidase activators, i.e. up-regulation in pre- and intermolt. Conclusion Cuticle hardening in crustaceans is a complex process that is precisely timed to occur in the post-molt stage of the molt cycle. We have identified differential expression patterns of several genes that are believed to be involved in biomineralization and sclerotization and propose possible regulatory mechanisms for these processes based on their expression profiles, such as the potential involvement of C-type lectin receptors and mannose binding protein in the regulation of calcification.

Kuballa, Anna V; Elizur, Abigail

2008-01-01

24

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

PubMed

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. PMID:23961226

Sugumar, V; Vijayalakshmi, G; Saranya, K

2013-01-01

25

Evaluation of a calcium pre-molt and low-energy molt program: Effects on laying hen behavior, production, and physiology before, during, and after a fasting or non-fasting molt  

Microsoft Academic Search

Commercial laying hens are typically induced to molt in an effort to cease egg production and extend their productive life for a second egg laying cycle. Furthermore, egg quality is improved and egg production is higher post-molt compared to pre-molt levels. This practice has been traditionally induced by a period of feed withdrawal ranging from 4 to 14 days accompanied

Emily Rebecca Dickey

2008-01-01

26

Free Amino Acid Changes in Normal and Eyestalkless Megalopa Larvae of the Blue Crab, Callinectes sapidus, during the Course of the Molt Cycle.  

National Technical Information Service (NTIS)

In normal megalopa larvae of Callinectes sapidus, the intracellular free amino compounds proline, taurine, alanine, glutamic acid and serine increased prior to the next molt. In larvae with eyestalks removed on the day of molt to the megalopa stage, the i...

R. K. Tucker J. D. Costlow

1974-01-01

27

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

28

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

2012-03-01

29

Neuropeptide Action in Insects and Crustaceans*  

PubMed Central

Physiological processes are regulated by a diverse array of neuropeptides that coordinate organ systems. The neuropeptides, many of which act through G protein–coupled receptors, affect the levels of cyclic nucleotides (cAMP and cGMP) and Ca2+ in target tissues. In this perspective, their roles in molting, osmoregulation, metabolite utilization, and cardiovascular function are highlighted. In decapod crustaceans, inhibitory neuropeptides (molt-inihibiting hormone and crustacean hyperglycemic hormone) suppress the molting gland through cAMP- and cGMP-mediated signaling. In insects, the complex movements during ecdysis are controlled by ecdysis-triggering hormone and a cascade of downstream neuropeptides. Adipokinetic/hypertrehalosemic/hyperprolinemic hormones mobilize energy stores in response to increased locomotory activity. Crustacean cardioacceleratory (cardioactive) peptide, proctolin, and FMRFamide-related peptides act on the heart, accessory pulsatile organs, and excurrent ostia to control hemolymph distribution to tissues. The osmoregulatory challenge of blood gorging in Rhodnius prolixus requires the coordinated release of serotonin and diuretic and antidiuretic hormones acting on the midgut and Malpighian tubules. These studies illustrate how multiple neuropeptides allow for flexibility in response to physiological challenges.

Mykles, Donald L.; Adams, Michael E.; Gade, Gerd; Lange, Angela B.; Marco, Heather G.; Orchard, Ian

2011-01-01

30

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

PubMed Central

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.

Nishida, Alberto K; Nordi, Nivaldo; Alves, Romulo RN

2006-01-01

31

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

2006-01-01

32

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

Microsoft Academic Search

Crustacean hyperglycemic hormone (CHH) is a pleiotropic neuropeptide that regulates carbohydrate and lipid metabolism, molting,\\u000a reproduction, and osmoregulation in decapod crustaceans. CHH elevates glucose levels in the hemolymph by stimulating glycogenolysis\\u000a in target tissues. It also inhibits ecdysteroidogenesis in the molting gland, or Y-organ (YO), possibly as a response to environmental\\u000a stress. CHH acts via binding to a membrane receptor

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

2009-01-01

33

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

34

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

35

Neurohormonal control of ecdysone production: Comparison of insects and crustaceans  

Microsoft Academic Search

Ecdysteroid synthesis is regulated in insects by prothoracicotropic hormone (PTTH) and in crustaceans by molt-inhibiting hormone (MIH). These neurohormones exert opposite effects on their respective target tissues, PTTH stimulating the prothoracic glands and MIH inhibiting the Y-organs. The present work reviews recent progress in the neurohormonal regulation of prothoracic gland and Y-organ function. The steroid products of these glands are

WENDY A. SMITH; DIETER SEDLMEIER

1990-01-01

36

Historical and current molting practices in the U.S. table egg industry.  

PubMed

Induced molting is a management practice used primarily by commercial egg producers to optimize the utilization of their layer flocks. Historically, flocks produced eggs for a laying cycle of 1 yr duration and then were sold. With induced molting, flocks are molted and returned to lay for additional laying periods, thereby spreading fixed costs over longer time and more units of production. It is estimated that today more than 75% of all flocks are molted as a part of a regular replacement program. The decision to molt or to operate an all-pullet program is based upon comparisons of flock performance and prices for replacement pullets, eggs, and feed. Justification for the use of molting, therefore, is in the higher total productivity of flocks, reduced costs associated with production, and reduced industry investments in breeder farms, rearing farms, and hatcheries. PMID:12817452

Bell, D D

2003-06-01

37

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

2013-08-01

38

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

Microsoft Academic Search

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

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

2007-01-01

39

Characterization of cDNA encoding molt-inhibiting hormone of the crab, Cancer pagurus; expression of MIH in non-X-organ tissues  

Microsoft Academic Search

Synthesis of ecdysteroids (molting hormones) by crustacean Y-organs is regulated by a neuropeptide, molt-inhibiting hormone (MIH), produced in eyestalk neural ganglia. We report here the molecular cloning of a cDNA encoding MIH of the edible crab, Cancerpagurus. Full-length MIH cDNA was obtained by using reverse transcription-polymerase chain reaction (RT-PCR) with degenerate oligonucleotides based upon the amino acid sequence of MIH,

Weiqun Lu; Geoffrey Wainwright; Lisa A. Olohan; Simon G. Webster; Huw H. Rees; Philip C. Turner

2001-01-01

40

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

41

Molt regulation in green and red color morphs of the crab Carcinus maenas: gene expression of molt-inhibiting hormone signaling components.  

PubMed

In decapod crustaceans, regulation of molting is controlled by the X-organ/sinus gland complex in the eyestalks. The complex secretes molt-inhibiting hormone (MIH), which suppresses production of ecdysteroids by the Y-organ (YO). MIH signaling involves nitric oxide and cGMP in the YO, which expresses nitric oxide synthase (NOS) and NO-sensitive guanylyl cyclase (GC-I). Molting can generally be induced by eyestalk ablation (ESA), which removes the primary source of MIH, or by multiple leg autotomy (MLA). In our work on Carcinus maenas, however, ESA has limited effects on hemolymph ecdysteroid titers and animals remain in intermolt at 7 days post-ESA, suggesting that adults are refractory to molt induction techniques. Consequently, the effects of ESA and MLA on molting and YO gene expression in C. maenas green and red color morphotypes were determined at intermediate (16 and 24 days) and long-term (~90 days) intervals. In intermediate-interval experiments, ESA of intermolt animals caused transient twofold to fourfold increases in hemolymph ecdysteroid titers during the first 2 weeks. In intermolt animals, long-term ESA increased hemolymph ecdysteroid titers fourfold to fivefold by 28 days post treatment, but there was no late premolt peak (>400 pg ?l(-1)) characteristic of late premolt animals and animals did not molt by 90 days post-ESA. There was no effect of ESA or MLA on the expression of Cm-elongation factor 2 (EF2), Cm-NOS, the beta subunit of GC-I (Cm-GC-I?), a membrane receptor GC (Cm-GC-II) and a soluble NO-insensitive GC (Cm-GC-III) in green morphs. Red morphs were affected by prolonged ESA and MLA treatments, as indicated by large decreases in Cm-EF2, Cm-GC-II and Cm-GC-III mRNA levels. ESA accelerated the transition of green morphs to the red phenotype in intermolt animals. ESA delayed molting in premolt green morphs, whereas intact and MLA animals molted by 30 days post treatment. There were significant effects on YO gene expression in intact animals: Cm-GC-I? mRNA increased during premolt and Cm-GC-III mRNA decreased during premolt and increased during postmolt. Cm-MIH transcripts were detected in eyestalk ganglia, the brain and the thoracic ganglion from green intermolt animals, suggesing that MIH in the brain and thoracic ganglion prevents molt induction in green ESA animals. PMID:24198255

Abuhagr, Ali M; Blindert, Jennifer L; Nimitkul, Sukkrit; Zander, Ian A; Labere, Stefan M; Chang, Sharon A; Maclea, Kyle S; Chang, Ernest S; Mykles, Donald L

2014-03-01

42

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

43

Effect of Eyestalk-Ablation on Circulating Ecdysteroids in Hemolymph of Snow Crabs, Chionoecetes opilio: Physiological Evidence for a Terminal Molt.  

PubMed

Bering Sea snow crabs (Chionoecetes opilio) are a commercially important crab harvested in the Bering Sea. Optimal management of this species requires an understanding of the biology of this crab that is currently incomplete. Fisheries managers apply a continuous growth model in their management of snow crab, which assumes that male crabs increase in size throughout their lifespan. Male snow crabs undergo a morphometric molt that leads to a disproportionate increase in chelae size and it is still debated whether this molt is associated with a terminal molt. This study was conducted to determine whether adult male C. opilio are anecdysic. Using current knowledge of the hormonal regulation of crustacean growth, snow crab physiology was manipulated to induce an increase in molting hormones (ecdysteroids). Since female snow crabs are known to undergo a terminal molt after attaining reproductive maturity, we compared ecdysteroid levels in eyestalk-ablated terminally molted females, small-clawed males and large-clawed males. Snow crabs were collected from the Bering Sea and maintained in circulating seawater at approximately 6°C. Animals were either eyestalk-ablated or left intact. Ecdysteroid levels in hemolymph were quantified using an enzyme-linked immunosorbant assay (ELISA). Circulating ecdysteroids were significantly higher in small-clawed male crabs when compared to large-clawed males or terminally molted females. Eyestalk-ablation increased circulating ecdysteroids in small-clawed males, but had no significant effect on circulating ecdysteroids in large-clawed males or in terminally molted females. PMID:21676758

Tamone, Sherry L; Adams, Melissa M; Dutton, Jessica M

2005-01-01

44

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

PubMed

Non-feed removal molting programme in commercial brown laying hens and its influence on pre-molting, post-molting and end of cycle egg quality traits were investigated. Overall 54 birds were randomly divided into three treatment groups and each group was fed with one of the following diets during 10 days of molting period: (i) grain barley, (ii) alfalfa meal, or (iii) commercial layer ration (non-molted control group). Eggs obtained from groups in pre-molting, post-molting and end of cycle periods were examined for several quality performance traits such as egg weight, specific gravity, shape index, shell strength, shell thickness, eggshell weight, haugh unit, albumen index, yolk index and yolk color. Results indicated that non-feed removal molting programme based particularly on grain barley had positive effect on egg quality traits in laying hens. Notably, yolk color and haugh unit, which are considered as the most important quality parameters from the consumer point of view, were relatively improved in barley molted group. PMID:18575968

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

2008-08-01

45

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

46

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

47

Salmon louse (Lepeophtheirus salmonis) transcriptomes during post molting maturation and egg production, revealed using EST-sequencing and microarray analysis  

PubMed Central

Background Lepeophtheirus salmonis is an ectoparasitic copepod feeding on skin, mucus and blood from salmonid hosts. Initial analysis of EST sequences from pre adult and adult stages of L. salmonis revealed a large proportion of novel transcripts. In order to link unknown transcripts to biological functions we have combined EST sequencing and microarray analysis to characterize female salmon louse transcriptomes during post molting maturation and egg production. Results EST sequence analysis shows that 43% of the ESTs have no significant hits in GenBank. Sequenced ESTs assembled into 556 contigs and 1614 singletons and whenever homologous genes were identified no clear correlation with homologous genes from any specific animal group was evident. Sequence comparison of 27 L. salmonis proteins with homologous proteins in humans, zebrafish, insects and crustaceans revealed an almost identical sequence identity with all species. Microarray analysis of maturing female adult salmon lice revealed two major transcription patterns; up-regulation during the final molting followed by down regulation and female specific up regulation during post molting growth and egg production. For a third minor group of ESTs transcription decreased during molting from pre-adult II to immature adults. Genes regulated during molting typically gave hits with cuticula proteins whilst transcripts up regulated during post molting growth were female specific, including two vitellogenins. Conclusion The copepod L.salmonis contains high a level of novel genes. Among analyzed L.salmonis proteins, sequence identities with homologous proteins in crustaceans are no higher than to homologous proteins in humans. Three distinct processes, molting, post molting growth and egg production correlate with transcriptional regulation of three groups of transcripts; two including genes related to growth, one including genes related to egg production. The function of the regulated transcripts is discussed in relation to post molting morphological changes in adult female salmon louse. There is clear evidence that transcription of the major yolk proteins is not induced before some of the post molting growth of abdomen and the genital segment has occurred. A hallmark for the observed growth is transcription of many putative cuticula proteins prior to the size increase.

Eichner, Christiane; Frost, Petter; Dysvik, Bjarte; Jonassen, Inge; Kristiansen, Bj?rn; Nilsen, Frank

2008-01-01

48

Crustaceans as a model for microgravity-induced muscle atrophy.  

PubMed

Atrophy of skeletal muscles is a serious problem in a microgravity environment. It is hypothesized that the unloading of postural muscles, which no longer must resist gravity force, causes an accelerated breakdown of contractile proteins, resulting in a reduction in muscle mass and strength. A crustacean model using the land crab, Gecarcinus lateralis, to assess the effects of spaceflight on protein metabolism is presented. The model is compared to a developmentally-regulated atrophy in which a premolt reduction in muscle mass allows the withdrawal of the large claws at molt. The biochemical mechanisms underlying protein breakdown involves both Ca(2+)-dependent and multicatalytic proteolytic enzymes. Crustacean claw muscle can be used to determine the interactions between shortening and unloading at the molecular level. PMID:11538617

Mykles, D L

1996-01-01

49

Crustaceans as a model for microgravity-induced muscle atrophy  

NASA Astrophysics Data System (ADS)

Atrophy of skeletal muscles is a serious problem in a microgravity environment. It is hypothesized that the unloading of postural muscles, which no longer must resist gravity force, causes an accelerated breakdown of contractile proteins, resulting in a reduction in muscle mass and strength. A crustacean model using the land crab, Gecarcinus lateralis, to assess the effects of spaceflight on protein metabolism is presented. The model is compared to a developmentally-regulated atrophy in which a premolt reduction in muscle mass allows the withdrawal of the large claws at molt. The biochemical mechanisms underlying protein breakdown involves both Ca^2+-dependent and multicatalytic proteolytic enzymes. Crustacean claw muscle can be used to determine the interactions between shortening and unloading at the molecular level.

Mykles, D. L.

50

Crustaceans as a model for microgravity-induced muscle atrophy  

NASA Technical Reports Server (NTRS)

Atrophy of skeletal muscles is a serious problem in a microgravity environment. It is hypothesized that the unloading of postural muscles, which no longer must resist gravity force, causes an accelerated breakdown of contractile proteins, resulting in reduction in muscle mass and strength. A crustacean model using the land crab, Gecarcinus lateralis, to assess the effects of spaceflight on protein meatabolism is presented. The model is compared to a developmentally-regulated atrophy in which a premolt reduction in muscle mass allows the withdrawal of the large claws at molt. The biochemical mechanisms underlying protein breakdown involves both Ca2(+) -dependent and multicatalytic proteolytic enzymes. Crustacean claw muscle can be used to determine the interactions between shortening and unloading at the molecular level.

Mykles, D. L.

1996-01-01

51

Organ weight and serum triglyceride responses of older (80 week) commercial laying hens fed an alfalfa meal molt diet.  

PubMed

Since one of the costs in the commercial egg industry is that of replacement pullets, commercial egg layer managers have opted to induce molt older hens in order to extend their productive life for additional egg laying cycles. Conventional molt induction involves the complete removal of feed for several days. However, this management practice can lead to deleterious physiological responses by the hen and subsequent susceptibility to infection by pathogens. Consequently less stressful molting regimens involving the feeding of low energy diets such as alfalfa have been developed. In this study, 80 week old laying hens that were deprived of feed or fed alfalfa meal during a nine day induced molt. Full fed hens were used as the control. On day 8 serum triglycerides were quantified and on day 9 hens were euthanized and the liver, spleen, heart, intestine, pancreas, ovary, and kidney were collected and weighed. Intestinal weight were highest in the non-molted hens, lower in the hens fed alfalfa, and lower still in the hens deprived of feed. Molted hens exhibited reduced weights of liver, heart, ovary, and pancreas compared to the non-molted hens. Serum triglycerides were highest in the non-molted hens, less in feed deprived hens, and the lowest in alfalfa fed hens. These results suggest that a comparable molt could be achieved with feeding alfalfa meal to 80 week hens compared to feed deprivation. PMID:18164195

Landers, K L; Moore, R W; Herrera, P; Landers, D A; Howard, Z R; McReynolds, J L; Bryd, J A; Kubena, L F; Nisbet, D J; Ricke, S C

2008-09-01

52

Timing of molt of barn swallows is delayed in a rare Clock genotype.  

PubMed

Photoperiodic responses are major factors entraining circannual life-cycles, functioning to adaptively synchronize annual routines to seasonal fluctuations in ecological conditions. Photoperiodism in physiology and behaviour is enforced by genes, including the vertebrate Clock orthologues, which are associated, for example, with phenology of migration in fish and breeding in birds. However, the role of Clock in photoperiodic plumage molt processes is unknown. We analyzed variation in molt schedules in relation to Clock genotype, using the long-distance migratory barn swallow (Hirundo rustica) as a model and by identifying males and females using molecular sexing techniques. Consistently with previous studies, we found one very common (Q 7) and two rare (Q 6, Q 8) variants of a functionally significant Clock polyglutamine repeat. Molt schedules of primary wing feathers of swallows during their wintering period in Nigeria differed among Clock genotypes: rare (1.1%) Q 7/Q 8 heterozygotes had significantly delayed molt compared to the other genotypes. Molt schedules did not differ between males and females, and no differential association between molt and Clock in relation to sex emerged. The same rare Clock genotype that exhibited delayed breeding in Europe was here found to delay molt in Africa. Though based on a limited number of Q 7/Q 8 individuals from an otherwise very large sample, these novel results suggest that Clock is involved in the photoperiodic control of both molt and breeding, potentially also via reciprocal carry-over effects. If confirmed in species with higher Clock polymorphism, present results may have far-reaching consequences for the study of photoperiodic control of molt and expression of annual routines. PMID:23638351

Saino, Nicola; Romano, Maria; Caprioli, Manuela; Fasola, Mauro; Lardelli, Roberto; Micheloni, Pierfrancesco; Scandolara, Chiara; Rubolini, Diego; Gianfranceschi, Luca

2013-01-01

53

Timing of molt of barn swallows is delayed in a rare Clock genotype  

PubMed Central

Photoperiodic responses are major factors entraining circannual life-cycles, functioning to adaptively synchronize annual routines to seasonal fluctuations in ecological conditions. Photoperiodism in physiology and behaviour is enforced by genes, including the vertebrate Clock orthologues, which are associated, for example, with phenology of migration in fish and breeding in birds. However, the role of Clock in photoperiodic plumage molt processes is unknown. We analyzed variation in molt schedules in relation to Clock genotype, using the long-distance migratory barn swallow (Hirundo rustica) as a model and by identifying males and females using molecular sexing techniques. Consistently with previous studies, we found one very common (Q7) and two rare (Q6, Q8) variants of a functionally significant Clock polyglutamine repeat. Molt schedules of primary wing feathers of swallows during their wintering period in Nigeria differed among Clock genotypes: rare (1.1%) Q7/Q8 heterozygotes had significantly delayed molt compared to the other genotypes. Molt schedules did not differ between males and females, and no differential association between molt and Clock in relation to sex emerged. The same rare Clock genotype that exhibited delayed breeding in Europe was here found to delay molt in Africa. Though based on a limited number of Q7/Q8 individuals from an otherwise very large sample, these novel results suggest that Clock is involved in the photoperiodic control of both molt and breeding, potentially also via reciprocal carry-over effects. If confirmed in species with higher Clock polymorphism, present results may have far-reaching consequences for the study of photoperiodic control of molt and expression of annual routines.

Romano, Maria; Caprioli, Manuela; Fasola, Mauro; Lardelli, Roberto; Micheloni, Pierfrancesco; Scandolara, Chiara; Rubolini, Diego; Gianfranceschi, Luca

2013-01-01

54

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

Microsoft Academic Search

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

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

2007-01-01

55

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

2013-05-01

56

Seasonal variation in the molt status of an oceanic copepod  

NASA Astrophysics Data System (ADS)

The timing of diapause, or suppressed development, in the dominant California Current copepod Calanus pacificus was examined in two ways. Diapause timing was inferred from changes in the abundance of deep, diapausing C. pacificus over a full year at a station off southern California, USA. Jaw phase and ecdysteroid content, indicators of molt cycle status in C. pacificus, were also examined to determine if shifts toward early molt phases, as are observed in diapausing Calanus, were also found among surface C. pacificus during periods when the abundance of deep, diapausing C. pacificus was increasing. The abundance of diapausing C. pacificus in deep water increased from June to mid-October, then declined from October to March. The percentage of surface-living C. pacificus CV with postmolt jaws, the earliest jaw phase, was significantly higher from June to mid-October than at other times. The ecdysteroid content of surface-living C. pacificus CV was also significantly lower during June to mid-October than during late October to May. Both of these changes indicate a shift to earlier molt phases in surface-living C. pacificus CV during periods of onset of diapause. However, the molt status of surface CV was variable from June to mid-October, suggesting that preparation for diapause was spatially or temporally heterogeneous. Hypotheses about environmental cues that induce diapause were evaluated, although the effect of cues on possibly sensitive stages could not be considered. The abundance of diapausing C. pacificus increased during a period of warm upper water column temperature and generally high and declining photoperiod; however, evaluation of the cues inducing diapause was inconclusive.

Johnson, Catherine Lynn

2004-07-01

57

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

PubMed

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 energy represents an easily adaptable diet for large laying hen production units. Alfalfa meal is readily available in most commercial locations and possesses many of the desirable properties of an ideal laying hen molt diet. In the current study hens at a commercial laying facility were molted by both alfalfa and feed deprivation. After the hens had reentered post-molt commercial egg production, eggs were examined for egg quality performance. Egg shell strength, albumen height, yolk height, weight, length, and yolk color were all tested using various mechanical techniques. The eggs were also sampled for testing by consumer sensory panels that assessed the desirability of the eggs' color and flavor/texture. Eggs laid by hens molted by alfalfa had a significantly lower (p<0.05) "a*" level of colorimetry. Eggs laid by hens molted with alfalfa also exhibited significantly higher (p<0.05) egg weights and length. In the consumer sensory test, there was no significant difference (p>0.05) in color or flavor/texture scores in eggs from either feed deprived or alfalfa molted hens. The consumer sensory and mechanical quality attributes indicates that alfalfa shows promise as an alternative molt induction diet by providing a single diet option for extending egg production into a second egg laying cycle. PMID:15627561

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

2005-05-01

58

Effect of adenosine on the growth of human T-lymphocyte leukemia cell line MOLT-4.  

PubMed

Adenosine has been observed to suppress the growth of MOLT-4 human leukemia cells in vitro. Changes in the cell cycle, especially increased percentage of cells in S phase, prolonged generation time, and induction of apoptosis at higher adenosine concentrations have been found to be responsible for the growth suppression. Dipyridamole, a drug inhibiting the cellular uptake of adenosine, reversed partially but significantly the adenosine-induced growth suppression. It follows from these results that the action of adenosine on the MOLT-4 cells comprises its cellular uptake and intracellular operation. These findings present new data on anticancer efficacy of adenosine. PMID:17882653

Streitová, Denisa; Weiterová, Lenka; Hofer, Michal; Holá, Jirina; Horváth, Viktor; Kozubík, Alois; Znojil, Vladimír

2007-09-01

59

Perferential loss of thin filaments during molt-induced atrophy in crab claw muscle  

Microsoft Academic Search

The closer muscle of the claw of a land crab Gecarcinus lateralis consists of slow, or tonic, fibers that undergo a sequential atrophy and restoration during each molting cycle. We have examined the ultrastructural organization of claw fibers during the process of protein degradation that takes place in proecdysial muscle atrophy. The myofibrial cross-sectional area is reduced fourfold by dissolution

D. L. Mykles; D. M. Skinner

1981-01-01

60

Binding pattern of 125iodine thyroxine and tri-iodothyronine in skin and liver tissues of spotted munia, Lonchura punctulata: co-relation to seasonal cycles of breeding and molting.  

PubMed

Prevalent notion about thyroid hormones is that thyroxine (T4) is a mere precursor and physiological effects of thyroid hormones are elicited by tri-iodothyronine (T3) after mono-deiodination of T4. Earlier studies on feather regeneration and molt done on spotted munia L. punctulata suggest that T4 (mono-deiodination suppressed by iopanoic acid and thyroidectomized birds) is more effective than T3 in inducing feather regeneration. The binding pattern of 125I labeled T4 and T3 has been investigated in the nuclei prepared from skin and liver tissues (samples obtained during different months) of spotted munia using scatchard plot analysis. The results show that binding capacity (B(max)--pmole/80 microgm DNA) of 125I-T3 to nuclei of skin was significantly higher in November as compared to April and June, whereas the binding affinity (Kd-10(-9)M(-1)) was significantly lower in November as compared to April and June. During November, B(max) for binding of T3 and T4 did not vary in liver and skin nuclei but Kd varied significantly. Binding capacity of 125I- T3 to skin and liver did not vary but binding affinity of 125I- T4 to skin was approximately 7 times higher than that of liver. The results suggest that T4 does show a variation in binding pattern that co-relates to the molting pattern of spotted munia. These variations might play important role in different physiological phenomenon in this tropical bird. The experiments do point towards the possibility of independent role of T4 as a hormone, however, further experiments need to be done to ascertain the role of T4 in this model and work out the exact molecular mechanism of action. PMID:24851410

Thapliyal, Ashish; Chandola-Saklani, Asha; Bhatt, Dinesh; Anthwal, Prashant

2014-05-01

61

Molecular characterization of an ecdysone inducible gene E75 of Chinese shrimp Fenneropenaeus chinensis and elucidation of its role in molting by RNA interference.  

PubMed

Ecdysone inducible gene, E75 is a primary target of ecdysone receptor (EcR), and is found to play a critical role in the molting process of arthropods. In this study, a cDNA encoding the E75 of Chinese shrimp Fenneropenaeus chinensis (FcE75) was cloned using RT-PCR and RACE techniques. FcE75 cDNA was 3611bp in length with an ORF of 2394bp. The deduced amino acid sequence of FcE75 had the highest sequence identity to E75 from a land crab Gecarcinus lateralis and E75 of the shrimp Metapenaeus ensis. Quantitative real-time PCR revealed a prominently high expression of FcE75 mRNA in the whole body RNA extract of late premolt period (D3) juvenile shrimp. The role of E75 in the process of shrimp molting was investigated using the RNA interference technique. Long double-stranded RNA corresponding to the FcE75 (dsE75) efficiently silenced the FcE75 transcript levels in juvenile F. chinensis. Further, injection with dsE75 completely arrested the molting process in experimental shrimp which eventually caused death. Setogenic analysis of the uropods from molt-arrested shrimp, showed defective epidermal retraction, poor development of setae and new cuticle. These results indicate that E75 might be related to the molting process and is essential for proper molting and survival of shrimp. This is the first report demonstrating the use of double stranded RNA to elucidate the possible role of E75 in the molting of decapod crustaceans. PMID:20184963

Priya, T A Jose; Li, Fuhua; Zhang, Jiquan; Yang, Changjian; Xiang, Jianhai

2010-07-01

62

Photoperiodic control of reproduction and molt in the kestrel, Falco tinnunculus.  

PubMed

An adaptive decline in average clutch size with progressive date of laying is characteristic of most bird species with a single clutch of variable size per year. The effect of photoperiod on timing of laying, clutch size, and subsequent molt was investigated in kestrel pairs breeding and raising their young in captivity. In natural daylight (nLD), clutch size, under ad libitum feeding, showed the same decline with date as in nature. Birds breeding later also started molt later and molted faster (more feathers simultaneously), so that all birds completed molt more or less at the same time. Constant long days (LD 17.5:6.5 and LD 13:11) from December 1 onward advanced both reproduction and molt. The LD 17.5:6.5 group developed the reproductive system faster, had a shorter courtship period, and laid eggs earlier than the LD 13:11 group. In both photoperiods there was a decrease in clutch size with progressive laying date, similar to that in nLD. Molt started in both groups at about the end of the laying period and slowed down in the longer photoperiod, especially in males. Plasma luteinizing hormone (LH) changes in the two photoperiods were different for males and females. Males showed the expected slower LH response in the shorter photoperiod, but the initial LH response by females was the same in both photoperiods. Data on LH, reproductive behavior, and body mass suggest that females have a wider annual reproductive window than males. Data on time of laying and number of eggs suggest that clutch size in the kestrel is determined by laying date itself, following an endogenous rhythm that is phase-locked to the reproductive cycle. PMID:2519599

Meijer, T

1989-01-01

63

Molt patterns and weight changes of the American woodcock  

USGS Publications Warehouse

A study of molt and changes in body weight of American Woodcock was conducted to better understand the summer and fall behavior of these birds and to indicate periods of physiological stress. The postnuptial molt of adults was a complete molt beginning in late June and ending by the middle of October. In contrast, the postjuvenal molt was a less intensive partial molt beginning in mid-July but also extending to the middle of October. Both male and female adult birds experienced weight loss in August during peak molt. Young birds gradually gained weight throughout the summer. Fat deposition was negatively correlated with molt while fall body weights were positively correlated with fat deposition. The data indicated that the majority of Maine woodcock are not physiologically prepared for migration until mid-October. Weights of adult males during the spring suggested that this is an important period of stress for these birds.

Owen, R.B.; Krohn, W.B.

1973-01-01

64

Crustacean oxi-reductases protein sequences derived from a functional genomic project potentially involved in ecdysteroid hormones metabolism - a starting point for function examination.  

PubMed

A transcriptomic assembly originated from hypodermis and Y organ of the crustacean Pontastacus leptodactylus is used here for in silico characterization of oxi-reductase enzymes potentially involved in the metabolism of ecdysteroid molting hormones. RNA samples were extracted from male Y organ and its neighboring hypodermis in all stages of the molt cycle. An equimolar RNA mix from all stages was sequenced using next generation sequencing technologies and de novo assembled, resulting with 74,877 unique contigs. These transcript sequences were annotated by examining their resemblance to all GenBank translated transcripts, determining their Gene Ontology terms and their characterizing domains. Based on the present knowledge of arthropod ecdysteroid metabolism and more generally on steroid metabolism in other taxa, transcripts potentially related to ecdysteroid metabolism were identified and their longest possible conceptual protein sequences were constructed in two stages, correct reading frame was deduced from BLASTX resemblances, followed by elongation of the protein sequence by identifying the correct translation frame of the original transcript. The analyzed genes belonged to several oxi-reductase superfamilies including the Rieske non heme iron oxygenases, cytochrome P450s, short-chained hydroxysteroid oxi-reductases, aldo/keto oxireductases, lamin B receptor/sterol reductases and glucose-methanol-cholin oxi-reductatses. A total of 68 proteins were characterized and the most probable participants in the ecdysteroid metabolism where indicated. The study provides transcript and protein structural information, a starting point for further functional studies, using a variety of gene-specific methods to demonstrate or disprove the roles of these proteins in relation to ecdysteroid metabolism in P. leptodactylus. PMID:24055302

Tom, Moshe; Manfrin, Chiara; Giulianini, Piero G; Pallavicini, Alberto

2013-12-01

65

Epibiotic Microbial Infestations of Cultured Crustaceans.  

National Technical Information Service (NTIS)

Microbial epibionts have continually hampered efforts to rear crustaceans. Although a variety of microbial agents may be responsible for mortalities on a variety of crustaceans, several characteristics are sufficiently similar to consider epibiotic microb...

W. S. Fisher

1977-01-01

66

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

2008-12-01

67

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

2009-07-01

68

Proecdysial changes in serum ecdysone titers, gastrolith formation, and limb regeneration following molt induction by limb autotomy and\\/or eyestalk removal in the land crab, Gecarcinus lateralis  

Microsoft Academic Search

The changes in serum ecdysone titers, gastrolith deposition, and limb regeneration were monitored at each stage of the molt cycle in the land crab, Gecarcinus lateralis. Animals were induced to molt by multiple-limb autotomy or eyestalk removal. The presence of ..cap alpha..-ecdysone and b-ecdysone (20-hydroxyecdysone) in the animals' serum was demonstrated chromatographically. ..beta..-ecdysone was the major circulating ecdysone, while ..cap

J. F. McCarthy; D. M. Skinner

1977-01-01

69

Effects of bird age, density, and molt on behavioral profiles of two commercial layer strains in cages.  

PubMed

Two commercial strains, Hy-Line W-36 and DeKalb XL, were moved to a laying house at 18 wk of age. They were housed 6 hens/layer cage at 2 densities (361 and 482 cm2/bird) with 2 replications each per strain/density combination. The high-density treatment contained 24 hens/replication and the low-density treatment contained 18 hens/replication for a total of 168 hens. Production parameters were measured during the first egg production cycle, the molt period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Behavioral observations were taken during 2 consecutive d at 26, 34, 43, 51, 62, 64, and 68 wk of age to examine behavioral patterns. Modified Hansen's tests were conducted concurrently to provide indication of the fearfulness levels of hens at the various stages of production. The production characteristics were similar for both strains. The hens kept at the higher density had lower (P < 0.01) hen-day production and (P < 0.05) daily egg mass. Appetitive behaviors were not affected by strain or density but were affected by the age of the hen and by molting. During the molt, feeding and drinking behavioral acts were fewer (P < 0.05) at 0.018 and 0.013 acts per bird/min, respectively, and standing behavior was highest. The results indicated that the frequencies of pecking inedible objects during the molt period were similar to the frequencies at 26 and 34 wk. Hens performed more acts of standing, and crouching and had lower frequency of movement during the molt. Those kept at a low density performed more movement acts. Feather pecking decreased as hens aged and increased when they molted but was not affected by strain or density. The frequency of aggression and submissive acts was significantly lower during the molt period. Behaviors were affected by strain, density, bird age, and molting; however, the patterns and number of aggressive acts did not increase to compromise the welfare status of the hens. Behaviors during the molt appeared consistent with mechanisms for conservation of body reserves. PMID:14761079

Anderson, K E; Davis, G S; Jenkins, P K; Carroll, A S

2004-01-01

70

Molting in land crabs: stimulation by leg removal.  

PubMed

If the Bermuda land crab, Gecarcinus lateralis, loses numerous walking legs or both chelipeds, it undergoes almost immediate preparations for molting with attendant limb regeneration. Injections of the arthropod-molting hormone, ecdysterone, have no effect in either intact animals or those missing legs. PMID:5450373

Skinner, D M; Graham, D E

1970-07-24

71

Molting in Land Crabs: Stimulation by Leg Removal  

Microsoft Academic Search

If the Bermuda land crab, Gecarcinus lateralis, loses numerous walking legs or both chelipeds, it undergoes almost immediate preparations for molting with attendant limb regeneration. Injections of the arthropod-molting hormone, ecdysterone, have no effect in either intact animals or those missing legs.

Dorothy M. Skinner; Dale E. Graham

1970-01-01

72

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

73

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

74

The King of Crustaceans: Lobsters  

NSDL National Science Digital Library

In the north Atlantic, the American Lobster is the undisputed king of crustaceans. Itâs also a tremendously important commercial catch. While all the other fisheries are collapsing, why are lobsters resisting the trend? In this video, Jonathan goes out with a Maine lobsterman to learn why, and he dives down below to find the biggest lobsters he has ever seen. This segment won a New England Emmy Award! Please see the accompanying study guide for educational objectives and discussion points.

Productions, Jonathan B.

2011-01-18

75

Utilizing different ratios of alfalfa and layer ration for molt induction and performance in commercial laying hens.  

PubMed

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. Although feed withdrawal (FW) is the most popular and effective method of molt induction, it has come under scrutiny due to food safety issues and animal welfare issues. This study involved feeding alfalfa mixed with layer ration at different ratios to hens to determine their ability to induce molt. The treatment ratios were 100% alfalfa (A100), 90% alfalfa and 10% layer ration (A90), and 70% alfalfa and 30% layer ration (A70). In addition, a fully fed (FF) nonmolted control and a FW negative control were used. Alfalfa is an insoluble, high fiber feedstuff with low metabolizable energy. Egg production for A90 and FW treatments ceased completely by d 6, whereas birds fed A100 and A70 ceased egg production by d 8. Ovary and oviduct weight of hens fed all molting diets decreased (P < 0.05) by an average of 1.5 to 2.5% (BW basis) compared with FF control during the 9-d molt induction period. As the percentage of layer ration increased, feed intake also increased and percentage of BW loss decreased during the 9-d molt induction period. Hens molted by FW lost an average of 25.8% BW, whereas A70 hens lost 18.9% BW. Nonmolted hens (FF) and A70 treatment hens had significantly lower (P < 0.05) egg production when compared with all other treatments over the 39-wk postmolt period. FF treatment hens also had lower (P < 0.05) albumen heights when compared with all other treatments. From these results, alfalfa or alfalfa mixed with layer ration appears to be viable alternatives to conventional FW methods for the successful induction of molt and retention of postmolt performance. PMID:15782903

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

2005-03-01

76

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

77

Molt and taxonomy of red-breasted nuthatches  

USGS Publications Warehouse

The postnuptial and postjuvenal molts of Red-breasted Nuthatches occur from middle June to late September. Some birds may be nearly finished with the complete molt before other individuals begin, so that specimens taken at any given time may differ by as much as two months in the age of their plumage. No characters useful in ageing birds after the completion of the autumn molt were found.....The proposed racial subdivision of Sitta canadensis was based on misleading evidence resulting from variation of plumage age in birds assumed to be seasonally comparable, sooting of birds in industrialized parts of the country, and variation in quality of prepared specimens.

Banks, R.C.

1970-01-01

78

Role of molting on the biodistribution of CeO2 nanoparticles within Daphnia pulex.  

PubMed

As all arthropods, microcrustaceans shed their chitinous exoskeleton (cuticule, peritrophic membrane) to develop and grow. While the molting is the most crucial stage in their life cycle, it remains poorly investigated in term of pollutant biodistribution within the organisms. In this paper, we used optical, electronic, and X ray-based microscopies to study the uptake and release of CeO2 nanoparticles by/from Daphnia pulex over a molting stage. We measured that D. pulex molts every 59 ± 21 h (confidence interval) with growth rates about 1.1 or 1.8 ?m per stage as a function of the pieces measured. Ingestion via food chain was the main route of CeO2 nanoparticles uptake by D. pulex. The presence of algae during the exposure to nanoparticles (sub-lethal doses) enhanced by a factor of 3 the dry weight concentration of Ce on the whole D. pulex. Nanoparticles were localized in the gut content, in direct contact with the peritrophic membrane, and on the cuticle. Interestingly, the depuration (24 h with Chlorella pseudomonas) was not efficient to remove the nanoparticles from the organisms. From 40% to 100% (depending on the feeding regime during exposure) of the CeO2 taken up by D. pulex is not release after the depuration process. However, we demonstrated for the first time that the shedding of the chitinous exoskeleton was the crucial mechanism governing the released of CeO2 nanoparticles regardless of the feeding regime during exposure. PMID:23664411

Auffan, Mélanie; Bertin, Delphine; Chaurand, Perrine; Pailles, Christine; Dominici, Christian; Rose, Jérôme; Bottero, Jean-Yves; Thiery, Alain

2013-08-01

79

California condor plumage and molt as field study aids  

USGS Publications Warehouse

An analysis is made of the reliability of plumage and molt characteristics of the California condor for estimating age and identifying individual birds. Neither character seems sufficiently reliable to use in more than a general way.

Wilbur, S.R.

1975-01-01

80

Decapod crustacean chelipeds: an overview.  

PubMed

The structure, growth, differentiation and function of crustacean chelipeds are reviewed. In many decapod crustaceans growth of chelae is isometric with allometry level reaching unity till the puberty moult. Afterwards the same trend continues in females, while in males there is a marked spurt in the level of allometry accompanied by a sudden increase in the relative size of chelae. Subsequently they are differentiated morphologically into crusher and cutter making them heterochelous and sexually dimorphic. Of the two, the major chela is used during agonistic encounters while the minor is used for prey capture and grooming. Various biotic and abiotic factors exert a negative effect on cheliped growth. The dimorphic growth pattern of chelae can be adversely affected by factors such as parasitic infection and substrate conditions. Display patterns of chelipeds have an important role in agonistic and aggressive interactions. Of the five pairs of pereiopods, the chelae are versatile organs of offence and defence which also make them the most vulnerable for autotomy. Regeneration of the autotomized chelipeds imposes an additional energy demand called "regeneration load" on the incumbent, altering energy allocation for somatic and/or reproductive processes. Partial withdrawal of chelae leading to incomplete exuviation is reported for the first time in the laboratory and field in Macrobrachium species. PMID:11022233

Mariappan, P; Balasundaram, C; Schmitz, B

2000-09-01

81

Temporal resolution in mesopelagic crustaceans.  

PubMed Central

Mesopelagic crustaceans occupy a dim-light environment that is similar to that of nocturnal insects. In a light-limited environment, the requirement for greater sensitivity may result in slower photoreceptor transduction and increased summation time. This should be reflected by a lower temporal resolution, as indicated by a lower critical flicker fusion frequency (CFF). Therefore, one would predict that the CFFs of mesopelagic organisms would be relatively low compared with those of their shallow-water relatives, just as nocturnal insects tend to have lower CFFs than diurnal insects. Using an electrophysiological apparatus that was adapted for shipboard use, the dark-adapted CFFs of a variety of species of mesopelagic crustaceans were determined using the electroretinogram. The parameter examined was the maximum CFF--the point at which further increases in irradiance no longer result in a faster flicker fusion frequency. The results summarized here indicate that there is a trend towards lower CFFs with increasing habitat depth, with some interesting exceptions.

Frank, T M

2000-01-01

82

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

83

Comparative Toxicology of Marine Fishes and Crustaceans.  

National Technical Information Service (NTIS)

Data collected on the effects of chemicals on marine fishes and crustaceans was evaluated for its predictive power of assessing risks to marine resources. The data sets consisted of acute median lethal concentrations (LC50s) and chromic maximum acceptable...

G. W. Suter A. E. Rosen

1986-01-01

84

Shell Disease Syndrome in Marine Crustaceans.  

National Technical Information Service (NTIS)

The shell disease syndrome has been reported from many freshwater and marine crustaceans of economic importance. Signs of the disease syndrome include erosion and pitting of the exoskeleton, resulting from activities of chitin-destroying microorganisms--b...

C. J. Sindermann

1989-01-01

85

Decapod Crustaceans of the Chesapeake Bay.  

National Technical Information Service (NTIS)

In this supplement 'Biota of Chesapeake Bay' a separate section is devoted to 'Taxa and Special Effects Summaries'. The author presents an assessment of the present status of knowledge of decapod crustaceans of Chesapeake Bay; their distribution and abund...

A. B. Williams

1972-01-01

86

Mineral Deposition in Bacteria-Filled and Bacteria-Free Calcium Bodies in the Crustacean Hyloniscus riparius (Isopoda: Oniscidea)  

PubMed Central

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.

Vittori, Milos; Rozman, Alenka; Grdadolnik, Joze; Novak, Urban; Strus, Jasna

2013-01-01

87

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

88

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...

89

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...

90

Artificial rain and cold wind act as stressors to captive molting and non-molting European starlings (Sturnus vulgaris).  

PubMed

Free-roaming animals continually cope with changes in their environment. One of the most unpredictable environmental phenomena is weather. Being able to respond to weather appropriately is crucial as it can be a threat to survival. The stress response, consisting of increases in heart rate and release of glucocorticoids, is an important mechanism by which animals cope with stressors. This study examined behavioral, heart rate, and corticosterone responses of captive European starlings (Sturnus vulgaris) to two aspects of weather mimicked under controlled conditions, a subtle (3 °C) decrease in temperature and a short, mild bout of rain. Both decreased temperature and exposure to rain elicited increases in heart rate and corticosterone in non-molting starlings. Molt is an important life history stage in birds that affects feather cover and may require a different response to weather-related stressors. We repeated the experiment in molting starlings and found increases in heart rate in response to rain and cold wind. However, the hypothalamic-pituitary-adrenal (HPA)-axis was suppressed during molt, as molting starlings did not increase corticosterone release in response to either stimulus. These data suggest these stimuli induce increased allostatic load in starlings, and that animals may adjust their response depending on the life-history stage. PMID:23277223

de Bruijn, Robert; Romero, L Michael

2013-03-01

91

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

92

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.  

PubMed

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 in the associated thoracic musculature; this unweighting atrophy occurs in intermolt and is ecdysteroid independent. Myostatin (Mstn) is a negative regulator of muscle growth in mammals; it suppresses protein synthesis, in part, by inhibiting the insulin/metazoan target of rapamycin (mTOR) signaling pathway. Signaling via mTOR activates translation by phosphorylating ribosomal S6 kinase (s6k) and 4E-binding protein 1. Rheb (Ras homolog enriched in brain), a GTP-binding protein, is a key activator of mTOR and is inhibited by Rheb-GTPase-activating protein (GAP). Akt protein kinase inactivates Rheb-GAP, thus slowing Rheb-GTPase activity and maintaining mTOR in the active state. We hypothesized that the large increase in global protein synthesis in claw muscle was due to regulation of mTOR activity by ecdysteroids, caused either directly or indirectly via Mstn. In the blackback land crab, Gecarcinus lateralis, a Mstn-like gene (Gl-Mstn) is downregulated as much as 17-fold in claw muscle during premolt and upregulated 3-fold in unweighted thoracic muscle during intermolt. Gl-Mstn expression in claw muscle is negatively correlated with hemolymph ecdysteroid level. Full-length cDNAs encoding Rheb orthologs from three crustacean species (G. lateralis, Carcinus maenas and Homarus americanus), as well as partial cDNAs encoding Akt (Gl-Akt), mTOR (Gl-mTOR) and s6k (Gl-s6k) from G. lateralis, were cloned. The effects of molting on insulin/mTOR signaling components were quantified in claw closer, weighted thoracic and unweighted thoracic muscles using quantitative polymerase chain reaction. Gl-Rheb mRNA levels increased 3.4-fold and 3.9-fold during premolt in claw muscles from animals induced to molt by eyestalk ablation (ESA) and multiple leg autotomy (MLA), respectively, and mRNA levels were positively correlated with hemolymph ecdysteroids. There was little or no effect of molting on Gl-Rheb expression in weighted thoracic muscle and no correlation of Gl-Rheb mRNA with ecdysteroid titer. There were significant changes in Gl-Akt, Gl-mTOR and Gl-s6k expression with molt stage. These changes were transient and were not correlated with hemolymph ecdysteroids. The two muscles differed in terms of the relationship between Gl-Rheb and Gl-Mstn expression. In thoracic muscle, Gl-Rheb mRNA was positively correlated with Gl-Mstn mRNA in both ESA and MLA animals. By contrast, Gl-Rheb mRNA in claw muscle was negatively correlated with Gl-Mstn mRNA in ESA animals, and no correlation was observed in MLA animals. Unweighting increased Gl-Rheb expression in thoracic muscle at all molt stages; the greatest difference (2.2-fold) was observed in intermolt animals. There was also a 1.3-fold increase in Gl-s6k mRNA level in unweighted thoracic muscle. These data indicate that the mTOR pathway is upregulated in atrophic muscles. Gl-Rheb, in particular, appears to play a role in the molt-induced increase in protein synthesis in the claw muscle. PMID:22279066

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

2012-02-15

93

Analysis of snail genes in the crustacean Parhyale hawaiensis: insight into snail gene family evolution.  

PubMed

The transcriptional repressor snail was first discovered in Drosophila melanogaster, where it initially plays a role in gastrulation and mesoderm formation, and later plays a role in neurogenesis. Among arthropods, this role of snail appears to be conserved in the insects Tribolium and Anopheles gambiae, but not in the chelicerates Cupiennius salei and Achaearanea tepidariorum, the myriapod Glomeris marginata, or the Branchiopod crustacean Daphnia magna. These data imply that within arthropoda, snail acquired its role in gastrulation and mesoderm formation in the insect lineage. However, crustaceans are a diverse group with several major taxa, making analysis of more crustaceans necessary to potentially understand the ancestral role of snail in Pancrustacea (crustaceans + insects) and thus in the ancestor of insects as well. To address these questions, we examined the snail family in the Malacostracan crustacean Parhyale hawaiensis. We found three snail homologs, Ph-snail1, Ph-snail2 and Ph-snail3, and one scratch homolog, Ph-scratch. Parhyale snail genes are expressed after gastrulation, during germband formation and elongation. Ph-snail1, Ph-snail2, and Ph-snail3 are expressed in distinct patterns in the neuroectoderm. Ph-snail1 is the only Parhyale snail gene expressed in the mesoderm, where its expression cycles in the mesodermal stem cells, called mesoteloblasts. The mesoteloblasts go through a series of cycles, where each cycle is composed of a migration phase and a division phase. Ph-snail1 is expressed during the migration phase, but not during the division phase. We found that as each mesoteloblast division produces one segment's worth of mesoderm, Ph-snail1 expression is linked to both the cell cycle and the segmental production of mesoderm. PMID:22466422

Hannibal, Roberta L; Price, Alivia L; Parchem, Ronald J; Patel, Nipam H

2012-05-01

94

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...

95

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

2007-02-01

96

Characterization of cDNA encoding molt-inhibiting hormone of the crab, Cancer pagurus; expression of MIH in non-X-organ tissues.  

PubMed

Synthesis of ecdysteroids (molting hormones) by crustacean Y-organs is regulated by a neuropeptide, molt-inhibiting hormone (MIH), produced in eyestalk neural ganglia. We report here the molecular cloning of a cDNA encoding MIH of the edible crab, Cancer pagurus. Full-length MIH cDNA was obtained by using reverse transcription-polymerase chain reaction (RT-PCR) with degenerate oligonucleotides based upon the amino acid sequence of MIH, in conjunction with 5'- and 3'-RACE. Full-length clones of MIH cDNA were obtained that encoded a 35 amino acid putative signal peptide and the mature 78 amino acid peptide. Of various tissues examined by Northern blot analysis, the X-organ was the sole major site of expression of the MIH gene. However, a nested-PCR approach using non-degenerate MIH-specific primers indicated the presence of MIH transcripts in other tissues. Southern blot analysis indicated a simple gene arrangement with at least two copies of the MIH gene in the genome of C. pagurus. Additional Southern blotting experiments detected MIH-hybridizing bands in another Cancer species, Cancer antennarius and another crab species, Carcinus maenas. PMID:11707332

Lu, W; Wainwright, G; Olohan, L A; Webster, S G; Rees, H H; Turner, P C

2001-10-31

97

Identifiable Cells in the Crustacean Stomatogastric Ganglion  

NSDL National Science Digital Library

Neural circuits rely on slight physiological differences between the component cells for proper function. When any circuit is analyzed, it is important to characterize the features that distinguish one cell type from another. This review describes the methods used to identify the neurons of the crustacean stomatogastric ganglion.

Amber E Hudson (Georgia Institute of Technology); Santiago Archila (Emory University); Astrid A Prinz (Emory University)

2010-10-01

98

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...

99

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

2013-06-01

100

Molting and Salmonella enterica serovar enteritidis infection: the problem and some solutions.  

PubMed

Induced molting is an important economic tool used by the egg industry to recycle an aging layer flock. It is estimated that approximately 70% of the flocks nationwide and almost 100% in California are molted annually. Considering that there are approximately 240 million hens in production in the U.S., a rough estimate of the numbers of hens molted every year would be between 144 and 168 million birds, a substantial number. There are many methods to induce molt, but feed removal until hens lose a specific weight is the most prevalent molt strategy in the U.S. However, experimental studies in our laboratory have shown that induced molting via feed removal depresses the immune system of hens and exacerbates a Salmonella enteritidis (SE) problem in a simulated flock situation. Molted hens excreted significantly higher SE numbers in the feces, had higher numbers of SE in internal organs, and exhibited more intestinal inflammation. Molted hens were 100- to 1,000-fold more susceptible to infection by SE and therefore more readily transmitted the organism to uninfected hens in neighboring cages. With the problems identified, solutions were sought, and several were successful in ameliorating the SE issue. Antibiotic therapy, vaccination, and use of low-energy, low-calcium diets to molt hens all dramatically decreased SE shedding during molt. All of the solutions provide the producer with many potential solutions to the SE food safety issue and still allow them to recycle their hens. PMID:12817457

Holt, P S

2003-06-01

101

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

102

Gene silencing in crustaceans: from basic research to biotechnologies.  

PubMed

Gene silencing through RNA interference (RNAi) is gaining momentum for crustaceans, both in basic research and for commercial development. RNAi has proven instrumental in a growing number of crustacean species, revealing the functionality of novel crustacean genes essential among others to development, growth, metabolism and reproduction. Extensive studies have also been done on silencing of viral transcripts in crustaceans, contributing to the understanding of the defense mechanisms of crustaceans and strategies employed by viruses to overcome these. The first practical use of gene silencing in aquaculture industry has been recently achieved, through manipulation of a crustacean insulin-like androgenic gland hormone. This review summarizes the advancements in the use of RNAi in crustaceans, and assesses the advantages of this method, as well as the current hurdles that hinder its large-scale practice. PMID:24705266

Sagi, Amir; Manor, Rivka; Ventura, Tomer

2013-01-01

103

The effects of long-term caging and molt of Single Comb White Leghorn hens on heterophil to lymphocyte ratios, corticosterone and thyroid hormones.  

PubMed

Two commercial strains of 18-wk-old Single Comb White Leghorn (SCWL) hens, HyLine W-36 and DeKalb XL, were housed six hens per cage in layer cages at two densities (361 and 482 cm2 per bird) with two replications each per strain and density combination. The high density treatment contained 24 hens per replication, and the low density treatment contained 18 hens per replication. Egg production was measured during the first egg production cycle, a molt (fast) period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Blood samples were obtained from six hens from each replicate in each strain and density combination (total of 48) at 20, 26, 34, 43, 51, 62, 64, and 68 wk of age. In addition, blood samples were obtained in a random order from hens in each cage, and the sequence of sampling was recorded (1 to 6). Blood smears were made, from which heterophil to lymphocyte ratios (H:L) were determined. Radioimmunoassays were conducted to determine levels of plasma corticosterone (CS), 3,5,3'-triiodothyronine (T3), and thyroxine (T4). The results indicated that strain did not affect percentage hen-day egg production (%HDP). Strain and cage density did not affect H:L, T3, T4, or CS. However, these parameters were affected by bird age, which was related to the egg production cycle. Plasma CS significantly (P < or = 0.001) increased during peak %HDP at 26 wk and 64 wk during the molt (fast), and H:L significantly (P < or = 0.001) increased during the molt (fast) at 64 wk. The sequence in which blood samples were obtained, from hens within a cage in sampling order, also increased plasma CS. The CS was significantly (P < or = 0.001) elevated in the third, fifth, and sixth hens from which blood samples were drawn. Plasma T3 and T4 changed during the production cycle. The T3 was significantly (P < or = 0.0001) depressed during peak egg production at 26 wk and during the molt (fast) at 64 wk when compared with the other time periods. Plasma T4 was depressed (P < or = 0.0001) at 51 wk and was elevated (P < or = 0.0001) at 64 wk during the molt (fast). The physiological and metabolic parameters of the different hen strains and cage densities were similar during egg production. However, CS, T3, T4, and H:L changed with age in relation to the egg production cycle. In addition, the physiological demands of peak egg production and molt (fast) appeared to be similar. PMID:10780646

Davis, G S; Anderson, K E; Carroll, A S

2000-04-01

104

Cuticular Biominerals of the Terrestrial Crustacean Oniscus asellus (Isopoda, Linnaeus 1758)  

NASA Astrophysics Data System (ADS)

Biomineralization is a phenomenon observed in many eukaryotic organisms and evidence suggests this process began relatively early in the evolution of multicellular life (Marin F et al. 1996). Crustaceans form a large fraction of all eukaryotic biomineralizers by incorporating calcium carbonate (CaCO3) into their cuticle. Terrestrial species are challenged in their production of CaCO3 by the absence of calcium-rich waters. To cope with this limitation, the terrestrial crustacean Oniscus asellus recycles up to 80% (Auzou G 1953) of its total calcium during the molting process. This feat is accomplished by separate molting of the front and back cuticle, with temporary storage of the calcium carbonate as amorphous calcium carbonate (ACC) in the front half (Ziegler A 1997). These processes infer a highly efficient and regulated mechanism for biomineralization that is most likely orchestrated by a myriad of proteins (Ziegler A et al. 2012). Until recently, investigations of biomineralization were largely directed toward understanding morphology and large-scale chemistry of the minerals, ignoring the mechanistic roles of biomacromolecules in mineralization processes. More recent work suggests a high involvement of these compounds on the formation of biominerals and, in some cases, the specific polymorphs thereof (Keene EC et al. 2010). This study focuses on identifying the components of the biological mineralization matrix at each stage of the process. Using chemical demineralization of the stored ACC, all biomacromolecules can be separated and purified for subsequent analysis by MALDI-TOF mass spectrometry. To link the localized biochemistry more intimately to the polymorph of calcium carbonate that forms in the animal, the inorganic phase (';the mineral') will be monitored at each life stage using XRD and TEM. This analysis will reveal the organic components of a very precise biomineralization mechanism and may shed insight on its evolutionary origin. References: Marin F, Westbroek P et al., 1996, Proc Nat Acad Sci 93:1554-1559 Auzou G, 1953, L Ann Sci Nat 15:71-98 Ziegler A, 1997, Zoomorphology 117:181-187 Ziegler A et al., 2012, Cryst Growth Des 12:646-655 Keene EC et al., 2010, Cryst Growth Des 10:1383-1389

Mergelsberg, S. T.; Mukhopadhyay, B.; Dove, P. M.

2013-12-01

105

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

106

CpG oligodeoxynucleotide 5mer-induced apoptosis in MOLT4 leukaemia cells does not require caspase 3 or new protein synthesis  

Microsoft Academic Search

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 insen- sitive to the caspase 3 inhibitor, Ac-DEVD-CHO, although the latter abrogated

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

2003-01-01

107

Body molt of male long-tailed ducks in the nearshore waters of the north slope, Alaska  

USGS Publications Warehouse

We examined the timing and intensity of body molt in relation to stage of remige growth for postbreeding adult male Long-tailed Ducks (Clangula hyemalis) off the coast of northern Alaska. During this period, remige and rectrix feathers are molted simultaneously with body feathers during the prebasic molt, which results in a period of increased energetic and nutritional demands. We collected birds from late July through mid-August and recorded intensity of molt in eight regions: head and neck, back and rump, greater coverts, lesser coverts, flank and sides, breast, belly, and tail. Using nonlinear regression, we estimated the peak intensity and variation for each region in relation to ninth primary length. We found little evidence of molt in the head and neck region. The greater and lesser coverts, and back and rump reached peak molt intensities earliest and were followed by tail, breast, and belly. Molt intensity in the flank and side region was highly variable and indicated a more prolonged molting pattern in relation to other regions. While body molt occurs simultaneously with wing molt, we found that molt among regions occurred in a staggered pattern. Long-tailed Ducks may employ this staggered molting pattern to minimize the energetic and nutritional requirements of molt.

Howell, M. D.; Grand, J. B.; Flint, P. L.

2003-01-01

108

Inexplicable Inefficiency of Avian Molt? Insights from an Opportunistically Breeding Arid-Zone Species, Lichenostomus penicillatus  

PubMed Central

The majority of bird species studied to date have molt schedules that are not concurrent with other energy demanding life history stages, an outcome assumed to arise from energetic trade-offs. Empirical studies reveal that molt is one of the most energetically demanding and perplexingly inefficient growth processes measured. Furthermore, small birds, which have the highest mass-specific basal metabolic rates (BMRm), have the highest costs of molt per gram of feathers produced. However, many small passerines, including white-plumed honeyeaters (WPHE; Lichenostomus penicillatus), breed in response to resource availability at any time of year, and do so without interrupting their annual molt. We examined the energetic cost of molt in WPHE by quantifying weekly changes in minimum resting metabolic rate (RMRmin) during a natural-molt period in 7 wild-caught birds. We also measured the energetic cost of feather replacement in a second group of WPHEs that we forced to replace an additional 25% of their plumage at the start of their natural molt period. Energy expenditure during natural molt revealed an energy conversion efficiency of just 6.9% (±0.57) close to values reported for similar-sized birds from more predictable north-temperate environments. Maximum increases in RMRmin during the molt of WPHE, at 82% (±5.59) above individual pre-molt levels, were some of the highest yet reported. Yet RMRmin maxima during molt were not coincident with the peak period of feather replacement in naturally molting or plucked birds. Given the tight relationship between molt efficiency and mass-specific metabolic rate in all species studied to date, regardless of life-history pattern (Efficiency (%) ?=?35.720•10?0.494BMRm; r2?=?0.944; p?=?<0.0001), there appears to be concomitant physiological costs entrained in the molt period that is not directly due to feather replacement. Despite these high total expenditures, the protracted molt period of WPHE significantly reduces these added costs on a daily basis.

Hoye, Bethany J.; Buttemer, William A.

2011-01-01

109

Inexplicable inefficiency of avian molt? Insights from an opportunistically breeding arid-zone species, Lichenostomus penicillatus.  

PubMed

The majority of bird species studied to date have molt schedules that are not concurrent with other energy demanding life history stages, an outcome assumed to arise from energetic trade-offs. Empirical studies reveal that molt is one of the most energetically demanding and perplexingly inefficient growth processes measured. Furthermore, small birds, which have the highest mass-specific basal metabolic rates (BMR(m)), have the highest costs of molt per gram of feathers produced. However, many small passerines, including white-plumed honeyeaters (WPHE; Lichenostomus penicillatus), breed in response to resource availability at any time of year, and do so without interrupting their annual molt. We examined the energetic cost of molt in WPHE by quantifying weekly changes in minimum resting metabolic rate (RMR(min)) during a natural-molt period in 7 wild-caught birds. We also measured the energetic cost of feather replacement in a second group of WPHEs that we forced to replace an additional 25% of their plumage at the start of their natural molt period. Energy expenditure during natural molt revealed an energy conversion efficiency of just 6.9% (±0.57) close to values reported for similar-sized birds from more predictable north-temperate environments. Maximum increases in RMR(min) during the molt of WPHE, at 82% (±5.59) above individual pre-molt levels, were some of the highest yet reported. Yet RMR(min) maxima during molt were not coincident with the peak period of feather replacement in naturally molting or plucked birds. Given the tight relationship between molt efficiency and mass-specific metabolic rate in all species studied to date, regardless of life-history pattern (Efficiency (%) ?=?35.720 x 10(-0.494BMRm); r²?=?0.944; p? =? or < 0.0001), there appears to be concomitant physiological costs entrained in the molt period that is not directly due to feather replacement. Despite these high total expenditures, the protracted molt period of WPHE significantly reduces these added costs on a daily basis. PMID:21311594

Hoye, Bethany J; Buttemer, William A

2011-01-01

110

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

111

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

112

AN INVESTIGATION OF DIFFERENT MOLTING TECHNIQUES WITH AN EMPHASIS ON ANIMAL WELFARE  

Microsoft Academic Search

SUMMARY We experimented to evaluate the effect of a number of molting techniques that appeared to be less stressful than the conventional feed withdrawal (FW) method on postmolt performance. The molting techniques involved a continuous FW (T1, control group), 1 d FW followed by feeding a grape pomace (GP) diet containing 10 ppm thyroxine (T2) ad libitum, feeding a corn

K. KESHAVARZ; F. W. QUIMBY

2002-01-01

113

Cyanobacterial Protease Inhibitor Microviridin J Causes a Lethal Molting Disruption in Daphnia pulicaria  

PubMed Central

Laboratory experiments identified microviridin J as the source of a fatal molting disruption in Daphnia species organisms feeding on Microcystis cells. The molting disruption was presumably linked to the inhibitory effect of microviridin J on daphnid proteases, suggesting that hundreds of further cyanobacterial protease inhibitors must be considered potentially toxic to zooplankton.

Rohrlack, Thomas; Christoffersen, Kirsten; Kaebernick, Melanie; Neilan, Brett A.

2004-01-01

114

Identification of molting fluid carboxypeptidase A (MF-CPA) in Bombyx mori.  

PubMed

Using microarray analyses, we identified carboxypeptidase A (MF-CPA), which was induced during pupal ecdysis in the wing discs of Bombyx mori. Here, we report the functional characterization of MF-CPA. MF-CPA has amino acid sequence similarities with the proteins in the carboxypeptidase A/B subfamily, from human to nematode. The MF-CPA gene is expressed during the molting periods in the epithelial tissues. MF-CPA is detected in the molting fluid, which fills the space between the old and new cuticle during molting. By Western blot analysis, we show that MF-CPA is secreted as a zymogen and processed in the molting fluid. Recombinant MF-CPA expressed in the insect cells has carboxypeptidase A activity. We propose that MF-CPA degrades the proteins from the old cuticle during the molting periods and contributes to recycling of the amino acids. PMID:15936966

Ote, Manabu; Mita, Kazuei; Kawasaki, Hideki; Daimon, Takaaki; Kobayashi, Masahiko; Shimada, Toru

2005-07-01

115

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

116

Distribution of crustacean diapause: micro- and macroevolutionary pattern and process  

Microsoft Academic Search

Theoretical predictions for the relationships between duration of dormancy, reproductive life span, and dispersal ability developed for plants in temporally varying environments are applied here to crustaceans. Mathematical models suggest that diapause duration should negatively covary with adult life span, and that both diapause and life span should negatively covary with dispersal ability. A survey of 167 crustacean species from

Nelson G. Hairston; Carla E. Cáceres

1996-01-01

117

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

118

Physiology and behavior of the hen during induced molt.  

PubMed

Feed deprivation has been adopted by the commercial egg industry to induce molt because it is the easiest method to apply and produces the best results. Feed deprivation, however, raises concerns about animal welfare. Birds respond to long-term feed deprivation in three phases. The first phase lasts at most a few days, during which physiological and behavioral adjustments ultimately reduce protein catabolism and energy expenditure. A temporary increase in plasma corticosterone may be observed at this time. Corticosterone promotes gluconeogenesis, helping to maintain plasma glucose levels in the initial stage of the fast. The corticosterone increase may also be linked to increased activity in feed-deprived birds. Hens have been observed to manifest temporarily increased levels of alertness and activity during the first 48 h of feed deprivation. Aggressive behavior of hens also has been observed to increase briefly during the first day of feed deprivation. The second phase is the longest, during which proteins are spared and lipids are catabolized to provide energy. This phase may last several months in some species; in the chicken it can continue more than 20 d. Hens show increasing amounts of resting behavior during this phase. The third phase begins when protein catabolism accelerates. A pathological stage eventually is reached when the bird will cease activity and no longer eat. The phased response to feed deprivation optimizes a tradeoff between the need to maintain constant levels of plasma glucose to sustain activity and the need to preserve critical body structures such as muscles and organs. Hens are capable of vigorous activity throughout feed deprivation periods typical of induced molts, which do not appear to take birds beyond the second phase of fasting. Hens having undergone extended fasts may also have improved livability. Alternative induced molting methods are being sought to reduce animal welfare concerns. The methods of current interest involve alteration of feeding regimen and cause at least some body weight loss. These alternative methods should be evaluated to ensure that they do not actually make aspects of hen welfare worse compared to feed withdrawal, which might happen if hens perceive feed restriction without being allowed to progress fully into the second phase of adaptation to feed deprivation. PMID:12817455

Webster, A B

2003-06-01

119

Changes in plasma thyroid hormones, luteinizing hormone (LH), estradiol, progesterone and corticosterone of laying hens during a forced molt.  

PubMed

1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather. PMID:2900123

Hoshino, S; Suzuki, M; Kakegawa, T; Imai, K; Wakita, M; Kobayashi, Y; Yamada, Y

1988-01-01

120

Life cycle and mating behavior of Zygotylenchus guevarai (Nematoda: Pratylenchidae) on excised Petroselinum crispum roots.  

PubMed

The life cycle and mating behavior of Zygotylenchus guevarai were observed in vitro on excised roots of Petroselinum crispum in gnotobiotic culture. Eggs hatched into juveniles whose appearance and structure were similar to those of the adults. Juveniles grew in size and each juvenile stage was terminated by a molt. Z. guevarai had four juvenile stages with the first molt occurred outside the egg shortly after hatching. After the final molt the juveniles differentiated into adult males and females. Mating was required for reproduction. After mating, fertilized females began to lay eggs. The life cycle from second stage juvenile to second stage juvenile was completed in 43 days. PMID:19090298

Karaka?, Mehmet

2007-11-15

121

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

122

Influence of molt on plasma protein electrophoretic patterns in bar-headed geese (Anser indicus).  

PubMed

Plasma protein electrophoresis is recognized as a reliable diagnostic tool in avian medicine; however, the influence of circannual phenomena such as molt on protein electrophoregrams is poorly documented. The molt is a period of heavy hormonal and metabolic change in birds. The purpose of this study was to investigate the effects of molt on total protein concentration and electrophoresis patterns in birds. Blood samples were taken from 19 Bar-headed Geese (Anser indicus) from mid-May to mid-August, at 15-day intervals. At the same time, molting stage of each bird was recorded. Total protein concentrations were measured and plasma agarose gel electrophoresis was performed on these samples. The Bar-headed Goose was chosen as a model, because they molt over a very short period. The total protein concentration and albumin, alpha-2, beta, and gamma fractions were at their minimum values during molt, whereas the prealbumin and alpha-1 fractions rose to their maximum levels. This study provides baseline information relevant to changes occurring in avian proteinograms throughout the molt. The increase in prealbumin and alpha-1 fractions may be related to an increase in plasma thyroid hormones during molt. The decrease observed in albumin, alpha-2, beta, and gamma fractions may be related to protein and energy shifts toward feather growth, as well as to an expansion of the circulatory system located around the feather follicles with secondary dilutional effects on protein fractions. From a clinical point of view, the observed changes associated with molting were less significant than initially expected, and would not likely results in incorrect diagnoses based on interpretation of the protein electrophoretic patterns. PMID:19617476

Roman, Yannick; Bomsel-Demontoy, Marie-Claude; Levrier, Julie; Ordonneau, Dorothée; Chaste-Duvernoy, Daniel; Jalme, Michel Saint

2009-07-01

123

Allometry of the Duration of Flight Feather Molt in Birds  

PubMed Central

We used allometric scaling to explain why the regular replacement of the primary flight feathers requires disproportionately more time for large birds. Primary growth rate scales to mass (M) as M0.171, whereas the summed length of the primaries scales almost twice as fast (M0.316). The ratio of length (mm) to rate (mm/day), which would be the time needed to replace all the primaries one by one, increases as the 0.14 power of mass (M0.316/M0.171?=?M0.145), illustrating why the time required to replace the primaries is so important to life history evolution in large birds. Smaller birds generally replace all their flight feathers annually, but larger birds that fly while renewing their primaries often extend the primary molt over two or more years. Most flying birds exhibit one of three fundamentally different modes of primary replacement, and the size distributions of birds associated with these replacement modes suggest that birds that replace their primaries in a single wave of molt cannot approach the size of the largest flying birds without first transitioning to a more complex mode of primary replacement. Finally, we propose two models that could account for the 1/6 power allometry between feather growth rate and body mass, both based on a length-to-surface relationship that transforms the linear, cylindrical growing region responsible for producing feather tissue into an essentially two-dimensional structure. These allometric relationships offer a general explanation for flight feather replacement requiring disproportionately more time for large birds.

Rohwer, Sievert; Ricklefs, Robert E.; Rohwer, Vanya G.; Copple, Michelle M.

2009-01-01

124

[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

2001-01-01

125

THE VITAMIN A OF A EUPHAUSIID CRUSTACEAN  

PubMed Central

The vitamin A of the euphausiid crustacean, Meganyctiphanes norvegica, consists almost wholly of the hindered cis isomer, neo-b (11-cis). In this animal vitamin A is concentrated almost entirely in the eyes; and its properties so closely resemble those of pure neo-b vitamin A as not in themselves to indicate that any other isomer is present. However, Fisher et al. (1955 b) have isolated a small fraction from this material which may be neo-c vitamin A (11, 13-dicis). The neo-b isomer was identified by its absolute absorption spectrum, the changes of absorption spectrum on isomerization, oxidation to neo-b retinene, and synthesis from the latter of rhodopsin. This identification is also in good accord with new, revised bioassays of Meganyctiphanes vitamin A by Plack et al. (1956).

Wald, George; Brown, Paul K.

1957-01-01

126

The Effect of Molting Upon the Vibration Receptor of the Spider (Achaearanea Tepidariorum).  

National Technical Information Service (NTIS)

The physiology and fine structure of the vibration receptor of the spider (Achaearanea tepidariorum) was studied throughout the process of molting. The physiological studies showed that there is no dramatic change in the receptor's vibration sensitivity a...

C. Walcott M. M. Salpeter

1966-01-01

127

Mortalities of Cultured Lobsters, 'Homarus', Associated with a Molt Death Syndrome.  

National Technical Information Service (NTIS)

Mortalities were observed in juvenile American lobsters, Homarus americanus, and hybrid H. americanus X H. gammarus, during several studies in which purified rations were used. Many animals died in the process of molting. Other animals which completed the...

1981-01-01

128

Cycles  

NSDL National Science Digital Library

Just about anywhere you look in the natural sciences you'll find a cycle of some description. From cells to individuals to populations and beyond, cyclical patterns exist on every scale. The following collection of Web sites follows on this theme: The first site (1) is an excellent, animated introduction to the cell cycle from Cells Alive! Users can also get a closer look at the stages of mitosis by following the links provided. The next site from the Center for Biological Timing contains a tutorial on chronobiology, the study of biological rhythms (2). Visitors will find a thorough overview of the human clock and related concepts, with emphasis on our 24-hour sleep-wake cycle. Speaking of internal cycles, the next site contains an interesting article from BBC News, relating how a woman's choice of men may vary in accordance with her menstrual cycle (3). The next site moves from internal to externally-evident cycles, namely the life cycle of the monarch butterfly. Monarch Watch provides a detailed description of the butterfly life cycle, from egg to larva to pupa to adult (4). Perhaps not quite as appealing as the monarch butterfly, but nevertheless intriguing, Schistosoma flatworms have a complicated life cycle involving humans and a particular group of snails. The University of California-Los Angeles Institute of the Environment offers an illustrated explanation of this highly specialized life cycle (5). The following site from Science New Online describes how global climate change is accelerating the annual life cycles of plants and animals around the world (6). On the level of population, the Natural History Museum of Los Angeles County offers the familiar example of the Canada lynx and the hare -- the same example used by countless textbooks to demonstrate the cyclical nature of predator-prey dynamics (7). And finally, Georgia State University provides a nicely simplified introduction to the energy cycle in living things, focusing on the transfer of energy from the sun to plants to animals (8).

Sohmer, Rachel.

129

Perferential loss of thin filaments during molt-induced atrophy in crab claw muscle  

SciTech Connect

The closer muscle of the claw of a land crab Gecarcinus lateralis consists of slow, or tonic, fibers that undergo a sequential atrophy and restoration during each molting cycle. We have examined the ultrastructural organization of claw fibers during the process of protein degradation that takes place in proecdysial muscle atrophy. The myofibrial cross-sectional area is reduced fourfold by dissolution of peripheral myofilaments and by focal erosion within the fibrila. As degradation continues, there is a preferential loss of thin filaments relative to thick filaments: (1) the average distance between thick filaments decreases from 59 to 45 nm, causing a 72% increase in packing density of thick filamets in cross section and (2) the relative numbers of thin and thick filaments decrease from an average ratio of 9:1 to 6:1. Despite these significant structural changes, the general organization of the arcomere is unaltered; the membrane surface density of the sacroplasmic reticulum and the A-band length remain unchanged. Although there is autophagy of some mitochondria, others retain their normal apperance, as do the nuclei. These data suggest that the specific degradation of contractile proteins in proecdysial atrophic muscle includes the differential breakdown of thin vesus thick filaments.

Mykles, D.L. (Univ. of Tennessee, Oak Ridge); Skinner, D.M.

1981-01-01

130

Comparison of several induced molting methods on subsequent performance of single comb White Leghorn hens.  

PubMed

Seventy-two-week-old Single Comb White Leghorn hens were induced to molt by 11 different methods 1) to determine the utility of molt-inducing procedures that employ full feeding, limited feeding, and fasting and 2) to determine the postmolt performance of hens induced to molt by fasting to varying degrees of body weight reduction (BWR) then fed postfast, prelay (PF-PL) diets varying in nutrient density. Induced molt treatments were full feeding of 10 and 15% guar meal diets to 30% BWR; limited feeding by withholding feed to 30% BWR, except for 6-hr feeding periods on every 3rd, 4th, and 5th recurring day; fasting to 25, 30, or 35% BWR then feeding either a pullet developer ration or a fortified molt ration (FR) for 21 days. Egg production, egg weight, shell quality, Haugh unit, feed consumption, and mortality were recorded for 33 weeks. Molt treatments produced few significant differences; nonmolted control hens had overall poor performance. Full feeding of the 15% guar meal diet caused a slow cessation and reinitiation of lay with acceptable lay performance. The 10% guar meal diet reduced livability. All recurring day, limited-feeding treatments conserved feed during the first 35 days of molt induction. The 3rd and 5th recurring day-feeding treatments were particularly effective and had acceptable lay performance and feed efficiency. Neither level of BWR nor type of PF-PL diet significantly affected postmolt performance. The 30% BWR-FR induced-molt method produced superior (but not significantly) postmolt lay performance. PMID:3601850

Zimmermann, N G; Andrews, D K; McGinnis, J

1987-03-01

131

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

132

Environmental Effects on Toxaphene Toxicity to Selected Fishes and Crustaceans.  

National Technical Information Service (NTIS)

Laboratory studies were conducted to determine lethal limits (96 hr TL50) for Toxaphene, salinity, temperature, and dissolved oxygen and their interaction effects on developmental stages of selected warm-temperate and subtropical fishes and crustaceans. S...

W. R. Courtenay M. H. Roberts

1973-01-01

133

[Genetic characteristics of human acute lymphoblastic leukemia cell line Molt-4].  

PubMed

This study was aimed to investigate the genetic characteristics of human acute lymphoblastic leukemia cell line Molt-4, and evaluate its application in measuring telomere length by Flow-FISH. Molt-4 cell line was cultured in suspension and subcultured regularly. Eight different passages of Molt-4 cells in exponential stage were selected.The growth curves were drawn by cell counting method, meanwhile calculating the population doubling times of cells,DNA ploidies were determined by flow cytometry,karyotypes were analyzed by G-banding and telomere lengths were measured by Southern blot. The results showed that the population doubling time of Molt-4 cell line was (1.315 ± 0.062) d, DNA ploidy index was (2.085 ± 0.0093) , and the telomere length was (32.05 ± 5.27) kb. There were no significant difference among different passages (P = 0.931,0.888 and 0.935 separately). The karyotypes showed that the chromosome numbers of Molt-4 cell line were from 91 to 99 in different metaphases, and the majority of them were hypertetraploid, and stable and recurrent structural abnormalities of chromosomes could be kept. It is concluded that the stable genetic characteristics and the longer telomere length of Molt-4 cell line makes it be a feasible control cells in measurement of telomere length by Flow-FISH. PMID:24762992

Ma, Xiao-Cai; Liu, Cong-Yan; Sun, Xue-Jing; He, Jing-Juan; Wan, Sui-Gui; Sun, Wan-Ling

2014-04-01

134

Corticosterone inhibits feather growth: potential mechanism explaining seasonal down regulation of corticosterone during molt.  

PubMed

Corticosterone (CORT) is seasonally modulated in many passerines, with plasma CORT concentrations lowest during the prebasic molt when all feathers are replaced. To explain why, we proposed that the birds downregulate natural CORT release during molt in order to avoid CORT's degradative effects on proteins and its inhibition of protein synthesis. If CORT exerted these effects during molt, it could slow protein deposition during feather production and potentially result in a longer period of degraded flight performance. To test this hypothesis, either empty or CORT-filled silastic implants were inserted into captive European starlings (Sturnus vulgaris) and white-crowned sparrows (Zonotrichia leucophrys) undergoing induced (feather replacement after plucking) and natural molts. We then measured the rate of feather re-growth by regularly measuring the length of primary, secondary, and tail feathers. CORT implanted birds showed a significantly decreased rate of feather growth compared to control animals. Basal CORT concentrations of induced molt and non-molting birds were also compared but no difference was noted. The results suggest a tradeoff; a complete set of new feathers may be more important to the survival of a bird than the ability of CORT to respond maximally to a stressor. PMID:16125989

Romero, L Michael; Strochlic, David; Wingfield, John C

2005-09-01

135

Ultraviolet polarisation sensitivity in the stomatopod crustacean Odontodactylus scyllarus  

Microsoft Academic Search

The ommatidia of crustacean eyes typically contain two classes of photoreceptors with orthogonally oriented microvilli. These\\u000a receptors provide the basis for two-channel polarisation vision in the blue–green spectrum. The retinae of gonodactyloid stomatopod\\u000a crustaceans possess a great variety of structural specialisations for elaborate polarisation vision. One type of specialisation\\u000a is found in the small, distally placed R8 cells within the

Sonja Kleinlogel; N. Justin Marshall

2009-01-01

136

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

2007-01-01

137

The sensory dorsal organs of crustaceans.  

PubMed

The cuticle of crustaceans bears numerous organs, of which the functions of many are unknown. One of these, the sensory dorsal organ (SDO), is present in a wide diversity of taxa. Here we critically review the variability, ultrastructure, distribution, and possible function of this enigmatic cuticular organ. Previous data are complemented by new observations on larvae and adults of various malacostracans. The SDO is composed of four sensors arranged as the corners of a square, the centre of which is occupied by a gland. Pores or pegs surrounding this central complex may also form part of the organ. The arrangement and the external aspect of the five main elements varies greatly, but this apparently has little impact on their ultrastructural organisation. The sensors and the gland are associated with a particularly thin cuticle. Each sensor contains four outer dendritic segments and the central gland is made of a single large cell. It is not yet known what this large cell secretes. The SDO is innervated from the tritocerebrum and therefore belongs to the third cephalic segment. A similar organ, here called the posterior SDO, has been repeatedly observed more posteriorly on the carapace. It resembles the SDO but has a greater number of sensors (usually six, but up to ten) apparently associated with only two outer dendritic segments. The SDO and the posterior SDO are known in the Eumalacostraca, the Hoplocarida, and the Phyllocarida. Some branchiopods also possess a 'dorsal organ' resembling both the SDO and the ion-transporting organ more typical of this group. This may indicate a common origin for these two functionally distinct groups of organs. New observations on the posterior SDO support the hypothesis that the SDO and the posterior SDO are homologous to the lattice organ complexes of the costracans. However, the relationship between the SDO and the dorsal cephalic hump of calanoid copepods remains unclear. No correlation can be demonstrated between the presence of a SDO and a particular ecological or biological trait. In fossils, the most convincing examples of SDO-like organs are found in some Late Cambrian arthropods from the Alum Shale of southern Sweden. They suggest that related organs might have been present in non-crustacean Cambrian arthropods. The distribution of the SDO and posterior SDO in extant and fossil crustaceans strongly suggests that these organs originated early in the history of the group, and are crucial to the functioning of these organisms. However, except for knowing that the sensors are chemoreceptors and that in a given organ a functional relationship probably exists between them and the gland, little is known about this function. The description of a SDO in freshwater carideans, which can be easily reared in a laboratory, opens the way for behavioural and physiological experiments to be undertaken that could prove crucial for the determination of this function. PMID:23279348

Lerosey-Aubril, Rudy; Meyer, Roland

2013-05-01

138

Haste Makes Waste: Accelerated Molt Adversely Affects the Expression of Melanin-Based and Depigmented Plumage Ornaments in House Sparrows  

PubMed Central

Background Many animals display colorful signals in their integument which convey information about the quality of their bearer. Theoretically, these ornaments incur differential production and/or maintenance costs that enforce their honesty. However, the proximate mechanisms of production costs are poorly understood and contentious in cases of non-carotenoid-based plumage ornaments like the melanin-based badge and depigmented white wing-bar in house sparrows Passer domesticus. Costly life-history events are adaptively separated in time, thus, when reproduction is extended, the time available for molt is curtailed and, in turn, molt rate is accelerated. Methodology/Principal Findings We experimentally accelerated the molt rate by shortening the photoperiod in order to test whether this environmental constraint is mirrored in the expression of plumage ornaments. Sparrows which had undergone an accelerated molt developed smaller badges and less bright wing-bars compared to conspecifics that molted at a natural rate being held at natural-like photoperiod. There was no difference in the brightness of the badge or the size of the wing-bar. Conclusions/Significance These results indicate that the time available for molt and thus the rate at which molt occurs may constrain the expression of melanin-based and depigmented plumage advertisements. This mechanism may lead to the evolution of honest signaling if the onset of molt is condition-dependent through the timing of and/or trade-off between breeding and molt.

Vagasi, Csongor I.; Pap, Peter L.; Barta, Zoltan

2010-01-01

139

Behavioural indicators of pain in crustacean decapods.  

PubMed

Whether invertebrates are able or not to experience pain is a highly controversial issue. An operative way to solve such a controversy might be to investigate their responses to potentially noxious stimuli and to collect evidence of their behavioural complexities as proxies of cognitive capacities. The principle of argument-by-analogy can be then applied to these data: the behaviour displayed by invertebrates is compared with that of "higher" animals, its similarity denoting the former's capacity to have analogous experiences. Here, the author discusses some examples, extracted from the literature on crustacean decapods, that pinpoint their nature of "sentient" animals. This review, however, also shows that research is still scanty in the field. The studies that examine the potential links between stress responses and pain experience are few, and the several papers that help elucidate cognitive abilities in decapods have been limited to a few taxa and are not specifically directed to the question of "sentience". On the contrary, also in the light of the expected revision of the current EU legislation in the matter, more scientific efforts should be expended on exploring the issue of pain experience in invertebrates. PMID:20061665

Gherardi, Francesca

2009-01-01

140

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

2011-01-01

141

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

142

Development of a dihydroartemisinin-resistant Molt-4 leukemia cell line.  

PubMed

Artemisinin generates cytotoxic free radicals when it reacts with iron. Its toxicity is more selective toward cancer cells because cancer cells contain a higher level of intracellular-free iron. We previously reported that dihydroartemisinin (DHA), an active metabolite of artemisinin, has selective cytotoxicity toward Molt-4 human lymphoblastoid cells. A concern is whether cancer cells could develop resistance to DHA after repeated administration, thus limiting its therapeutic efficacy. In the present study, we developed a DHA-resistant Molt-4 cell line (RTN) by exposing Molt-4 cells to gradually increasing concentrations of DHA in vitro. The half-maximal inhibitory concentration (IC50) of DHA for RTN cells is 7.1-times higher than that of Molt-4 cells. RTN cells have a higher growth rate than Molt-4 cells. In addition, we investigated the toxicities of two more potent synthetic artemisinin compounds, artemisinin dimer-alcohol and artemisinin-tagged holotransferrin toward RTN cells; RTN cells showed no significant cross-resistance to these compounds. PMID:24922643

Park, Jungsoo; Lai, Henry C; Singh, Mallika; Sasaki, Tomikazu; Singh, Narendra P

2014-06-01

143

75 FR 1597 - Western Pacific Crustacean Fisheries; 2010 Northwestern Hawaiian Islands Lobster Harvest Guideline  

Federal Register 2010, 2011, 2012, 2013

...Atmospheric Administration RIN 0648-XT33 Western Pacific Crustacean Fisheries; 2010 Northwestern Hawaiian Islands Lobster Harvest...lobster fishery is managed under the Fishery Management Plan for Crustacean Fisheries of the Western Pacific Region. The...

2010-01-12

144

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

145

A potential role for fatty acid biosynthesis genes during molting and cuticle formation in Caenorhabditis elegans.  

PubMed

Caenorhabditis elegans undergoes a developmental molting process that involves a coordinated interplay among diverse intracellular pathways. Here, we investigated the functions of two fatty acid biosynthesis genes; pod-2, encoding acetyl-CoA carboxylase, and fasn-1, encoding fatty acid synthase, in the C. elegans molting process. Although both the pod-2 and fasn-1 genes were expressed at constant levels throughout C. elegans development, knockdown of the proteins encoded by these genes using RNA interference produced severe defects in triglyceride production, molting, and reproduction that were coupled to suppression of NAS-37, a metalloprotease. An assessment of the structure and integrity of the cuticle using a COL-19::GFP marker and Hoechst 33258 staining showed that downregulation of either pod-2 or fasn-1 impaired cuticle formation and disrupted the integrity of the cuticle and the hypodermal membrane. PMID:21524356

Li, Yingxiu; Paik, Young-Ki

2011-04-01

146

Molt-induced muscle atrophy decreases the zinc content of the pectoralis of the Giant Canada Goose ( Branta canadensis maxima )  

Microsoft Academic Search

Summary During molt-induced atrophy of the pectoralis muscle of the Giant Canada Goose (Branta canadensis maxima), the zinc content of the muscle was significantly reduced (p?0.0139), though the concentration of zinc per unit weight of muscle appeared higher (p?0.0232). Zinc lost from the muscle during molt could be utilized for growth of the new flight feathers.

B. W. C. Rosser; J. C. George

1986-01-01

147

Sex Pheromone Activity of the Molting Hormone, Crustecdysone, on Male Crabs (Pachygrapsus crassipes, Cancer antennarius, and C. anthony).  

National Technical Information Service (NTIS)

The pheromone released by premolt female Pachygrapsus crassipes is a heat stable non-ionic polar lipid. The coincidence of the release of the pheromone and the nubial molt suggested that the molting hormone, crustecdysone, may also function as a sex phero...

J. S. Kittredge M. Terry F. T. Takahashi

1971-01-01

148

Use of dietary thyroxine as an alternate molting procedure in spent turkey breeder hens.  

PubMed

In the turkey industry, molting is traditionally achieved by reducing photoperiod and withdrawing feed and water for several days. Although it is the most effective method, this practice is discouraged in Canada and alternative strategies need to be established. Thyroid hormone levels naturally change during molt, and dietary thyroxine (T4) supplementation was previously shown to induce molt in chickens. This study aimed at evaluating the effectiveness of supplemental dietary T4 in inducing molt in spent turkey breeder hens. One hundred twenty 75-wk-old hens were randomly divided into 4 groups (5 floor pens/replicates, 5 hens each) with the control group kept under a 14-h photoperiod and fed a breeder's diet throughout, whereas hens from the 3 other groups were supplemented with 40 ppm (45.76 mg/kg) T4 for 10 d. One treatment group was maintained under 14 h of light and fed a breeder's diet, whereas the 2 others were subjected to a drop in photoperiod to 6 h during or after supplementation and then were fed a maintenance diet. Egg production, feed intake, BW, molt, and plasma levels of T4, prolactin, and luteinizing hormone were measured. All treated hens ceased laying by d 20; however, several individuals spontaneously returned to lay when left on 14 h of light, suggesting incomplete involution of the reproductive tract. Supplementation significantly reduced feed consumption and induced rapid BW loss. All hens returned to their initial weight by the end of the experiment. Most treated hens initiated molt by d 8 of supplementation and all completed molt by d 37. Plasma T4 in treated hens increased significantly by d 3 (P < 0.05) and remained significantly higher than in controls until d 9 (P < 0.01). Levels returned to initial values by d 35. Prolactin levels did not appear to be influenced by T4 but were mainly dependent on photoperiod and reproductive stage, whereas luteinizing hormone levels remained low throughout. In summary, dietary supplementation with 40 ppm (45.76 mg/kg) T4 was successful in inducing molt in turkey breeder hens. However, dropping the photoperiod was necessary to completely reset the reproductive system. PMID:20008807

Gulde, V A L; Renema, R; Bédécarrats, G Y

2010-01-01

149

Applying fenoxycarb at the penultimate instar triggers an additional ecdysteroid surge and induces perfect extra larval molting in the silkworm.  

PubMed

When the juvenile hormone analog fenoxycarb was topically applied to the silkworm Bombyx mori at the beginning of the 3rd or 4th (penultimate) instar, an extra larval molt was induced. The 5th instar period was shortened to about 5 days and the extra 6th instar ranged from 8 to more than 20 days, depending on the dose applied. Starvation before fenoxycarb treatment strongly enhanced the incidence of extra molting up to 100%. When 1 ng was applied in the 4th instar after a 2-day starvation, most larvae underwent an extra molt, metamorphosed to pupae, then to fertile adults. Combining starvation and fenoxycarb application thus induces a perfect extra molt efficiently. In perfect extra molting larvae, profiles of total ecdysteroid titer during the 4th and 5th instars were similar to that during the 4th instar in the control, and the ecdysteroid profile during the extra 6th instar was similar to that during the control 5th (last) instar. At ecdysteroid peaks, 20-hydroxyecdysone (20E) and ecdysone (E), generally regarded as the active molting hormone and its precursor, had similar titers in the 6th instar, whereas E was much less than 20E in the 4th and 5th instars in the extra molting larvae. E was also abundant only in the last larval instar in the control. These results suggest that both 20E and E contents are important for regulation of larval molt and metamorphosis in silkworms and that fenoxycarb triggers the extra molt by inducing an additional larval molt type of ecdysteroid surge before the last larval instar. PMID:12392697

Kamimura, Manabu; Kiuchi, Makoto

2002-10-01

150

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

PubMed Central

Background The 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 Findings The seasonal change in photoperiod was manipulated to accelerate the molt rate. This treatment simulates the case of naturally late-breeding birds. House sparrows Passer domesticus experiencing accelerated molt developed shorter flight feathers with more fault bars and body feathers with supposedly lower insulation capacity (i.e. shorter, smaller, with a higher barbule density and fewer plumulaceous barbs). However, the wing, tail and primary feather lengths were shorter in fast-molting birds if they had an inferior body condition, which has been largely overlooked in previous studies. The rachis width of flight feathers was not affected by the treatment, but it was still condition-dependent. Conclusions/Significance This study shows that sedentary birds might face evolutionary costs because of the molt rate–feather quality conflict. This is the first study to experimentally demonstrate that (1) molt rate affects several aspects of body feathers as well as flight feathers and (2) the costly effects of rapid molt are condition-specific. We conclude that molt rate and its association with feather quality might be a major mediator of life history trade-offs. Our findings also suggest a novel advantage of early breeding, i.e. the facilitation of slower molt and the condition-dependent regulation of feather growth.

Vagasi, Csongor I.; Pap, Peter L.; Vincze, Orsolya; Benko, Zoltan; Marton, Attila; Barta, Zoltan

2012-01-01

151

Planktonic crustacean assemblages of three reservoirs from the Mexican  

Microsoft Academic Search

The reservoirs Trinidad Fabela (TF), Ignacio Ramírez (IR) and Tepuxtepec (T) are located along an altitude gradient in the upper Lerma Basin of the Mexican Central Plateau. Between July 1993 and June 1994, the planktonic crustacean assemblages of these systems were dominated by seven cladoceran species and five copepod species. Specific richness ranged from 13 species in TF to 16

Ana María; Arroyo Bustos; Eugenia López López; Domenico Voltolina

152

Temporal adaptations in visual systems of deep-sea crustaceans  

Microsoft Academic Search

The temporal characteristics of the visual systems of deep-sea crustaceans were examined at varying light levels. Experimental organisms were collected off Hawaii and southern California in 1991 and 1992, and continually maintained in the dark. At the University of California Santa Barbara Marine Laboratory, the temporal components of both visual interneuron activity and electroretinograms (ERGs) of adult Gnathophausia ingens were

J. F. Moeller; J. F. Case

1995-01-01

153

Leaf choice by crustaceans in a mangrove forest in Queensland  

Microsoft Academic Search

The feeding behaviour of leaf eating crustaceans feeding on leaves shed by Avicennia marina, Bruguiera gymnorhiza and Rhizophora stylosa in the mangrove forest at Myora Springs, Queensland, Australia was studied between 1980 and 1984. Individual Sesarma erythrodactyla (carapace >9 mm long), one of the most abundant species of crabs in the forest, processed approximately half a leaf from any of

J. Camilleri

1989-01-01

154

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

155

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

156

Aspartic proteinases in the digestive tract of marine decapod crustaceans  

Microsoft Academic Search

Decapod crustaceans synthesize highly active proteolytic enzymes in the midgut gland and release at least a part of them into the stomach where they facilitate the first step in peptide hydrolysis. The most common proteinases in the gastric fluid characterized so far are serine proteinases, that is, trypsin and chymotrypsin. These enzymes show highest activities at neutral or slightly alkaline

Fernando García-carreÑo; Manuel Díaz López; Laura Celis-guerrero; Reinhard Saborowski

2006-01-01

157

PHOTOINDUCED TOXICITY OF FLUORANTHENE TO SEVEN MARINE BENTHIC CRUSTACEANS  

EPA Science Inventory

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 diffe...

158

The Development of Crustacean Limbs and the Evolution of Arthropods  

Microsoft Academic Search

Arthropods exhibit great diversity in the position, number, morphology, and function of their limbs. The evolutionary relations among limb types and among the arthropod groups that bear them (insects, crustaceans, myriapods, and chelicerates) are controversial. Here, the use of molecular probes, including an antibody to proteins encoded by arthropod and vertebrate Distal-less (Dll and Dlx) genes, provided evidence that common

Grace Panganiban; Angela Sebring; Lisa Nagy; Sean Carroll

1995-01-01

159

Annual survival and site fidelity of Steller'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

160

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

161

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

2012-11-01

162

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

163

Molt-associated changes in hematologic and plasma biochemical values and stress hormone levels in African penguins (Spheniscus demersus).  

PubMed

Handling, including blood collection, has often been discouraged in molting penguins because it is considered an additional stress imposed on birds already experiencing major physiologic stress associated with molting. To evaluate the degree of physiologic stress posed by molting, we compared the hematologic and plasma biochemical values and hormone levels of molting and nonmolting African penguins, Spheniscus demersus. Five male and 5 female penguins randomly chosen were given complete physical examinations, were weighed, and blood samples were taken at 7 time points before, during, and after the molt. Data were analyzed by linear mixed-model analysis of variance. Throughout the study, behavior and appetite remained normal. Catecholamine levels were highly variable within and among subjects, whereas mean corticosterone levels were significantly different between baseline, molt, and postmolt values. Significant differences from baseline values were observed in many of the hematologic analytes; however, only decreases in hematocrit and red blood cell count values were considered clinically significant. Anemia due to experimentally induced blood loss as a possible cause of the significant hematologic changes was ruled out based on results of a follow-up control study during the nonmolt season, which showed no significant changes in hematocrit level or total red blood cell counts when using similar sampling protocols, which indicates that these changes were associated with molt. PMID:24640930

Mazzaro, Lisa M; Meegan, Jenny; Sarran, Delphine; Romano, Tracy A; Bonato, Vinicius; Deng, Shibing; Dunn, J Lawrence

2013-12-01

164

Detection of tropomyosin and determination of proteins in crustacean oils.  

PubMed

Tropomyosin is known to be the main allergen in crustaceans and the objective of this study was to investigate if this protein could be detected in commercial crustacean oils from Antarctic krill (Euphausia superba) and the zooplankton Calanus finmarchicus. We also examined the possibility of determining the protein content in the oils by direct amino acid analysis. Western blotting showed that a commercial antibody against shrimp tropomyosin cross-reacted with a protein of similar size in Antarctic krill and C. finmarchicus. The protein tentatively identified as tropomyosin, was also detected in krill oil products, but not in oils from C. finmarchicus. The acetone-heptane method used for extracting proteins in the oils is however not optimal. Other extraction methods should therefore be considered when investigating the presence of allergenic proteins in oils. Direct amino acid analysis on oils should be further explored as a method for determining the total amount of proteins present. PMID:23768329

Vang, Birthe; Mæhre, Hanne K; Jensen, Ida-J; Olsen, Ragnar L

2013-11-01

165

Some population characteristics of planktonic crustaceans in neusiedler see  

Microsoft Academic Search

Between May 1970 and May 1972 the total standing crop of planktonic crustaceans was highest in summer (288–693 ind. x103·m-3), whilst winter values varied from 8 to 58 ind. x103·m-3. The dominant species are Arctodiaptomus spinosus Daday and Diaphanosoma brachyurum Liéven. For Arctodiaptomus 4–5 generations per year were found, resting stages were never present. Diaphanosoma starts its development from the

Alois Herzig

1974-01-01

166

Crustacean Muscle Plasticity: Molecular Mechanisms Determining Mass and Contractile Properties  

Microsoft Academic Search

Two crustacean models for understanding molecular mechanisms of muscle plasticity are reviewed. Metabolic changes underlying muscle protein synthesis and degradation have been examined in the Bermuda land crab, Gecarcinus lateralis. During proecdysis, the claw closer muscle undergoes a programmed atrophy, which results from a highly controlled breakdown of myofibrillar proteins by Ca2+-dependent and, possibly, ATP\\/ubiquitin-dependent proteolytic enzymes. The advantage of

Donald L Mykles

1997-01-01

167

Comparative analysis of an excitatory motor unit in crustaceans  

Microsoft Academic Search

1.The leg stretcher muscle motor unit was examined in five different decapod crustaceans (Gecarcinus, Grapsus, Goniopsis, Homarus andPanulirus) with the objective of establishing interrelationships between nerve terminal and muscle fiber properties.2.In each species, nerve terminals varied greatly in their capacity for facilitation of transmitter release (Fe), muscle fibers varied with respect to sarcomere length (SL), and a wide range of

R. G. Sherman

1977-01-01

168

The complete mitochondrial DNA sequence of the crustacean Artemia franciscana  

Microsoft Academic Search

The complete mitochondrial DNA (mtDNA) sequence of the brine shrimp Artemia franciscana has been determined. It extends the present knowledge of mitochondrial genomes to the crustacean class and supplies molecular markers for future comparative studies in this large branch of the arthropod phylum. Artemia mtDNA is 15,822 nucleotides long, and when compared with its Drosophila counterpart, it shows very few

José Ramón Valverde; Beatriz Batuecas; Carmen Moratilla; Roberto Marco; Rafael Garesse

1994-01-01

169

Comparative study of the spectral sensitivities of mesopelagic crustaceans  

Microsoft Academic Search

The spectral sensitivities of 12 species of mesopelagic crustaceans were studied by means of electrophysiological recordings.\\u000a Nine of the species are vertical migrators, while 3 are not, and 9 species possess bioluminescent organs, while 3 are not\\u000a bioluminescent. All species had a single peak of spectral sensitivity with maxima between 470?nm and 500?nm. There was no\\u000a apparent correlation between sensitivity

T. M. Frank; E. A. Widder

1999-01-01

170

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

Microsoft Academic Search

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\\u000a explained this redistribution: (1) ecological change: redistribution of molting brant reflects improvements in coastal foraging\\u000a habitats, which have undergone a succession toward salt-tolerant plants due to increased coastal erosion and saltwater intrusion\\u000a as induced by

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

171

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

172

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

PubMed Central

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 (3 g/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, 85 mg/L in drinking water). Fifteen birds were slaughtered at 5% of peak of production for each group to collect their pituitary glands. 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 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.

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

2012-01-01

173

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. PMID:23761066

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

2013-10-01

174

Effect of xanthurenic acid on P-450-dependent biotransformation by molting glands in vitro  

Microsoft Academic Search

Incubation of molting glands from the crayfishProcambarus clarkii (Y-organ) and the silkwormBombyx mori (prothoracic gland) with 23,24-[2H4]-2-deoxyecdysone resulted in the production of deutero-ecdysone; this biotransformation was inhibited in the presence of xanthurenic acid. When the experiments were performed under an18O2 atmosphere, the18O atom was introduced into ecdysone, as confirmed by mass spectrometry. We therefore suggest that xanthurenic acid inhibits P-450-dependent

M. Ohnishi; Y. Naya

1994-01-01

175

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

176

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

177

A molt-associated chitinase cDNA from the spruce budworm, Choristoneura fumiferana.  

PubMed

Chitinase (CfChitinase) cDNA from the spruce budworm, Choristoneura fumiferana, was cloned using reverse transcription PCR and cDNA library screening. The CfChitinase cDNA was determined to be 2856 nucleotides long with the longest open reading frame made up of 1671 nucleotides that encoded a protein that was 557 amino acid long with a predicted molecular mass of 62 kDa. The deduced amino acid sequence showed 76-79% identity with other lepidopteran chitinases. Northern blots revealed that transcripts of CfChitinase appeared prior to each molt and peaked on the day of ecdysis from the second instar to the pupal stage but disappeared immediately after the molt. No transcripts could be detected in the early first instar prior to the spinning of the hibernaculum or in the diapausing second instars or during the intermolt periods of the other instars. Western blot analysis revealed that the protein appeared 12 h prior to ecdysis and disappeared 12 h after ecdysis from the sixth instar to pupal stage. The 20-hydroxyecdysone analog, tebufenozide (RH5992), induced expression of CfChitinase in the early stage of the sixth instar and caused a precocious and incomplete molt into an extra larval stage. During the sixth instar to the pupal molt, transcripts could be detected only in the epidermis and fat bodies, but not in the midgut. Western blots showed that the protein was present in the epidermis and midgut, but not in the fat bodies. The recombinant protein expressed in Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) showed high levels of chitinolytic activity with an optimal pH range 6-9. Glycosylation appeared to be necessary for the chitinolytic activity and secretion of the recombinant protein. PMID:12429133

Zheng, Y; Zheng, S; Cheng, X; Ladd, T; Lingohr, E J; Krell, P J; Arif, B M; Retnakaran, A; Feng, Q

2002-12-01

178

76 FR 77214 - Hawaii Crustacean Fisheries; 2012 Northwestern Hawaiian Islands Lobster Harvest Guideline  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA838 Hawaii Crustacean Fisheries; 2012 Northwestern Hawaiian Islands Lobster Harvest Guideline AGENCY: National Marine Fisheries Service...

2011-12-12

179

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

180

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

2010-12-01

181

Proteomic analysis of insect molting fluid with a focus on enzymes involved in chitin degradation.  

PubMed

Cuticular chitin degradation is extremely important for insect growth and development, which has not been fully understood thus far. One obstacle to understanding this mechanism is the lack of a systematic analysis of the chitinolytic enzymes involved in cuticular chitin degradation. In this study, we used the silkmoth Bombyx mori as a model organism and compared proteomic analyses for larval-pupal (L-P) and pupal-adult (P-A) molting fluids using tandem mass tag quantitative mass spectrometry. There were 195 proteins identified from both L-P and P-A molting fluids. A total of 170 out of 195 proteins were deduced to be secretory and were enriched for GO terms associated with chitin metabolism and proteolysis by using AgriGO. Although the chitinolytic enzymes are encoded by many insect genes, the proteomics analysis unexpectedly showed that only four chitinolytic enzymes with the combination "211" were abundant in both molting fluids, namely, two insect GH18 Chitinase family members (ChtI and ChtII), one bacterial-type GH18 Chitinase (Chi-h), and one insect GH20 hexosaminidase (Hex1). A tissue-specific and stage-specific gene expression pattern verified that the "211" enzymes are involved in cuticular chitin degradation. This work first demonstrates that specific enzymes ChtI, ChtII, Chi-h, and Hex1 can be assigned to cuticular chitin degradation. PMID:24779478

Qu, Mingbo; Ma, Li; Chen, Peng; Yang, Qing

2014-06-01

182

NHR-23 dependent collagen and hedgehog-related genes required for molting  

SciTech Connect

Highlights: {yields} NHR-23 is a critical regulator of nematode development and molting. {yields} The manuscript characterizes the loss-of-function phenotype of an nhr-23 mutant. {yields} Whole genome expression analysis identifies new potential targets of NHR-23. {yields} Hedgehog-related genes are identified as NHR-23 dependent genes. {yields} New link between sterol mediated signaling and regulation by NHR-23 is found. -- Abstract: NHR-23, a conserved member of the nuclear receptor family of transcription factors, is required for normal development in Caenorhabditis elegans where it plays a critical role in growth and molting. In a search for NHR-23 dependent genes, we performed whole genome comparative expression microarrays on both control and nhr-23 inhibited synchronized larvae. Genes that decreased in response to nhr-23 RNAi included several collagen genes. Unexpectedly, several hedgehog-related genes were also down-regulated after nhr-23 RNAi. A homozygous nhr-23 deletion allele was used to confirm the RNAi knockdown phenotypes and the changes in gene expression. Our results indicate that NHR-23 is a critical co-regulator of functionally linked genes involved in growth and molting and reveal evolutionary parallels among the ecdysozoa.

Kouns, Nathaniel A.; Nakielna, Johana; Behensky, Frantisek [Laboratory of Model Systems, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague (Czech Republic)] [Laboratory of Model Systems, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague (Czech Republic); Krause, Michael W. [Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (United States)] [Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (United States); Kostrouch, Zdenek [Laboratory of Model Systems, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague (Czech Republic)] [Laboratory of Model Systems, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague (Czech Republic); Kostrouchova, Marta, E-mail: marta.kostrouchova@lf1.cuni.cz [Laboratory of Model Systems, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague (Czech Republic)] [Laboratory of Model Systems, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague (Czech Republic)

2011-10-07

183

Molecular Characterizations of a Novel Putative DNA-Binding Protein LvDBP23 in Marine Shrimp L. vannamei Tissues and Molting Stages  

PubMed Central

Background Litopenaeus Vannamei, well known as pacific white shrimp, is the most popular shrimp in the world shrimp market. Identification and characterization of shrimp muscle regulatory genes are not only important for shrimp genetic improvement, but also facilitate comparative genomic tools for understanding of muscle development and regeneration. Methodology/Principal Findings A novel mRNA encoding for a putative DNA-binding protein LvDBP23 was identified from Litopenaeus vannamei abdominal muscle cDNA library. The LvDBP23 cDNA contains 639 nucleotides of protein-coding sequence with deduced 212 amino acids of predicted molecular mass 23.32 kDa with glycine-rich domain at amino acid position 94–130. The mRNA sequence is successfully used for producing LvDBP23 recombinant protein in sf9 insect cell expression system. The expression of LvDBP23 mRNA is presented in abdominal muscle and swimming leg muscle, as well as other tissues including intestine, lymphoid and gill. The mRNA expression has the highest level in abdominal muscle in all tested tissues. LVDBP23 transcript during the molt cycle is highly expressed in the intermolt stage. In vitro nucleic acid-binding assays reveal that LvDBP23 protein can bind to both ssDNA and dsDNA, indicating its possible role of regulation of gene transcription. Conclusions/Significance We are the first to report a DNA-binding protein identified from the abdominal muscle tissue of marine shrimp L. Vannamei. Its high-level specific expression during the intermot stage suggests its role in the regulation of muscle buildup during the growth phase of shrimp molt cycle.

Laoong-u-thai, Yanisa; Zhao, Baoping; Phongdara, Amornrat; Yang, Jinzeng

2011-01-01

184

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

185

Metamorphosis in the Cirripede Crustacean Balanus amphitrite  

PubMed Central

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.

Maruzzo, Diego; Aldred, Nick; Clare, Anthony S.; H?eg, Jens T.

2012-01-01

186

POST-EXERCISE LACTATE PRODUCTION AND METABOLISM IN THREE SPECIES OF AQUATIC AND TERRESTRIAL DECAPOD CRUSTACEANS  

PubMed

Aquatic and terrestrial crustaceans are dependent on both aerobic and anaerobic metabolism for energy production during exercise. Anaerobic energy production is marked by an accumulation of lactate in both muscle tissue and haemolymph, but the metabolic fate of lactate is not clear. Lactate recycling via gluconeogenesis and the potential role of carbonic anhydrase (CA) in supplying bicarbonate for the carboxylation of pyruvate were investigated in three species of decapod crustaceans: Callinectes sapidus (aquatic), Cardisoma guanhumi (semi-terrestrial) and Gecarcinus lateralis (terrestrial). CA activity was found in mitochondria and cytoplasmic fractions of gill, hepatopancreas and muscle of all three species. Significant activities of key enzymes of gluconeogenesis (e.g. pyruvate carboxylase, phosphoenolpyruvate carboxykinase and fructose bisphosphatase), however, could not be detected. Exercise to exhaustion produced a species-specific pattern of accumulation and clearance of lactate in tissue and haemolymph, indicating a differential degree of reliance on anaerobic energy production. Treatment with acetazolamide, a CA inhibitor, did not significantly alter the pattern of lactate dynamics in animals given repeated bouts of exhaustive exercise interspersed with periods of recovery. Injection of [U-14C]lactate resulted in the appearance of label in both muscle glycogen and excreted carbon dioxide, suggesting multiple metabolic fates for lactate. Lactate turnover rates for G. lateralis were similar to those reported for fish. In these animals, gluconeogenesis possibly proceeds via the reversal of pyruvate kinase, or via the typical Cori cycle but so slowly that the uncatalysed supply of bicarbonate is sufficient to keep pace with the low activities of pyruvate carboxylase and the subsequent low rates of pyruvate carboxylation. PMID:9317667

Walsh

1994-01-01

187

Immunocytochemical detection of acetylated alpha-tubulin and Drosophila synapsin in the embryonic crustacean nervous system.  

PubMed

The caridean shrimp Palaemonetes argentinus Nobili is well suited for studying developmental aspects of the crustacean nervous system due to its rapid embryonic development and short reproductive cycle. In the present paper, we demonstrate the pattern of central axonal pathways in embryos of this species by immunohistochemical detection of acetylated alpha-tubulin. Development of the neuropil was elucidated by using an antibody to a Drosophila synapsin. In the ventral nerve cord, the segmental axonal scaffold consists of the paired lateral connectives, a median connective, and the anterior and posterior commissures. Three nerve roots were found to branch off each ganglion anlage, i.e. the main segmental nerve root, a smaller posterior nerve and the intersegmental nerve. However, this pattern is different in the mandibular segment where no intersegmental nerve and only one commissure was encountered. The anterior part of the brain consists of a tritocerebral and a deutocerebral anlage as well asthe anlage of the medial protocerebrum. The latter is connected to the eyestalk via the protocerebral tract. The sequence of development of the eyestalk ganglia was demonstrated in specimens which were stained with the anti-synapsin antibody. The medulla terminalis and medulla interna are the first neuropils to appear and are still fused in early stages. Later, the medulla interna splits off the medulla terminalis. The lamina ganglionaris is the last of the eyestalk neuropils to develop. These findings prove that immunocytochemistry against acetylated alpha-tubulin and synapsin are valuable tools for studying the development of the crustacean nervous system. PMID:9240564

Harzsch, S; Anger, K; Dawirs, R R

1997-06-01

188

A comparison of cell killing by heat and\\/or x rays in Chinese hamster V79 cells, Friend erythroleukemia mouse cells, and human thymocyte MOLT4 cells  

Microsoft Academic Search

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

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

1983-01-01

189

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

PubMed Central

New neurons are produced and integrated into circuits in the adult brains of many organisms, including crustaceans. In some crustacean species, the 1st- generation neuronal precursors reside in a niche exhibiting characteristics analogous to mammalian neurogenic niches. However, unlike mammalian niches where several generations of neuronal precursors coexist, 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 1st-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 1st-generation precursor pool, because although these cells divide and produce a continuous efflux of 2nd-generation cells from the niche, the population of 1st-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.

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

2011-01-01

190

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

2012-06-01

191

Quantification of Stress in Lobsters: Crustacean Hyperglycemic Hormone, Stress Proteins, and Gene Expression1  

Microsoft Academic Search

SYNOPSIS. Various methods for the quantification of stress in crustaceans have been developed in our laboratory. An ELISA was developed for the crustacean hyperglycemic hormone (CHH) from the lobster, Homarus americanus. It is sen- sitive to as little as 0.2 fmol of peptide. Increases in hemolymph CHH were ob- served following emersion. Significant levels of hemolymph CHH were also mea-

ERNEST S. CHANG; SHARON A. CHANG; RAINER KELLER; P. SREENIVASULA REDDY; MARK J. SNYDER; JEFFREY L. SPEES

192

Usage of energy reserves in crustaceans during starvation: Status and future directions  

Microsoft Academic Search

In this paper, we review the current knowledge about the usage of carbohydrates, lipids and proteins as energy source by marine crustaceans during starvation. Crustaceans are a large and diverse group including some economically important species. The efforts to culture them for human consumption has prompted the interest to understand the preferences of energy sources to be applied for feed

Arturo Sánchez-Paz; Fernando García-Carreño; Adriana Muhlia-Almazán; Alma B. Peregrino-Uriarte; Jorge Hernández-López; Gloria Yepiz-Plascencia

2006-01-01

193

Mini review Usage of energy reserves in crustaceans during starvation: Status and future directions  

Microsoft Academic Search

In this paper, we review the current knowledge about the usage of carbohydrates, lipids and proteins as energy source by marine crustaceans during starvation. Crustaceans are a large and diverse group including some economically important species. The efforts to culture them for human consumption has prompted the interest to understand the preferences of energy sources to be applied for feed

Arturo Sanchez-Paz; Fernando Garcia-Carreno; Adriana Muhlia-Almazan; Alma B. Peregrino-Uriarte; Jorge Hernandez-Lopez; Gloria Yepiz-Plascencia

194

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

195

The origin, transport and cleavage of the molt-associated cuticular protein CECP22 from Calpodes ethlius (Lepidoptera, Hesperiidae).  

PubMed

CECP22 (Calpodes ethlius Cuticular Protein 22 kDa) is a molt associated protein found in the cuticle of C. ethlius larvae and pupae. The mRNA for the CECP22 cuticular protein is expressed in the epidermis and fat body during the intermolt. The protein itself accumulates in intermolt hemolymph, but at molting, when the cuticle is being digested, it is also found in the cuticle of surface integument, tracheae, foregut and hindgut and in the molting fluid. CECP22 exists in two forms. The large form (19.17 kDa, pI 6.2) becomes smaller (16.1 kDa, pI 7.4) by cleavage at the proteolytic cleavage site (position 170) with amidation of the C-terminal. The small, more basic peptide, appears only at molting, first in the cuticle and then in the molting fluid. It is presumed to be the active form of an amidase involved in the earliest stages of cuticle degradation. The inactive form accumulates in the hemolymph during the long intermolt and probably represents an abundant source of precursor enzyme that can be provided to all cuticle containing organs for a precise initiation of cuticle degradation. PMID:12770299

Marcu, O; Locke, M

1999-09-01

196

Evaluation of feeding various sources of distillers dried grains with solubles in non-feed-withdrawal molt programs for laying hens.  

PubMed

An experiment was conducted using 588 Hy-Line W-36 hens (68 wk of age) to evaluate if laying hens can be successfully molted by ad libitum feeding various levels of 3 sources of distillers dried grains with solubles (DDGS). Treatment 1 consisted of a 47% corn (C):47% soy hulls (SH) molt diet (C:SH) fed for 28 d (positive control). Treatments 2, 3, and 4 were molt diets containing 94% DDGS from the 3 sources fed for 28 d. Treatments 5, 6, and 7 were 32% C: 42% SH: 20% DDGS, from each of the 3 DDGS sources, also fed for 28 d. At the end of the 28-d molt period, all hens were fed a 16% CP corn-soybean meal layer diet. Body weight loss during the molt period was significantly greater (P < 0.05) for hens fed the C:SH diet (26%) than hens fed the diets containing DDGS, and the reduction in BW loss varied among DDGS sources. Feed intake was lower (P < 0.05) for the C:SH control treatment compared with most DDGS treatments. Hens fed the C:SH diet had egg production near 0% during the last 3 wk of the molt period. Hens on the other treatments did not have mean egg production below 17% during the molt period (wk 1 to 4), and the reduction in egg production varied among DDGS sources. Postmolt hen-day egg production (5-41 wk) did not significantly differ among treatments; however, egg mass and egg specific gravity were generally reduced (P < 0.05) for hens fed the 94% DDGS molt diets compared with hens fed the C:SH diet. This study showed that molt and postmolt performance responses varied among DDGS sources; however, none of the molt diets containing 20 to 94% DDGS yielded molt period reductions in BW or egg production similar to a 47% C: 47% SH diet. PMID:24879692

Bland, Kelly; Utterback, Pam; Koelkebeck, Ken; Parsons, Carl

2014-06-01

197

Insect Neuropeptide Bursicon Homodimers Induce Innate Immune and Stress Genes during Molting by Activating the NF-?B Transcription Factor Relish  

PubMed Central

Background Bursicon is a heterodimer neuropeptide composed of two cystine knot proteins, bursicon ? (burs ?) and bursicon ? (burs ?), that elicits cuticle tanning (melanization and sclerotization) through the Drosophila leucine-rich repeats-containing G protein-coupled receptor 2 (DLGR2). Recent studies show that both bursicon subunits also form homodimers. However, biological functions of the homodimers have remained unknown until now. Methodology/Principal Findings In this report, we show in Drosophila melanogaster that both bursicon homodimers induced expression of genes encoding antimicrobial peptides (AMPs) in neck-ligated adults following recombinant homodimer injection and in larvae fat body after incubation with recombinant homodimers. These AMP genes were also up-regulated in 24 h old unligated flies (when the endogenous bursicon level is low) after injection of recombinant homodimers. Up-regulation of AMP genes by the homodimers was accompanied by reduced bacterial populations in fly assay preparations. The induction of AMP expression is via activation of the NF-?B transcription factor Relish in the immune deficiency (Imd) pathway. The influence of bursicon homodimers on immune function does not appear to act through the heterodimer receptor DLGR2, i.e. novel receptors exist for the homodimers. Conclusions/Significance Our results reveal a mechanism of CNS-regulated prophylactic innate immunity during molting via induced expression of genes encoding AMPs and genes of the Turandot family. Turandot genes are also up-regulated by a broader range of extreme insults. From these data we infer that CNS-generated bursicon homodimers mediate innate prophylactic immunity to both stress and infection during the vulnerable molting cycle.

Li, Sheng; Gilbert, Lawrence I.; Stanley, David; Song, Qisheng

2012-01-01

198

Measurement of Neuropeptides in Crustacean Hemolymph via MALDI Mass Spectrometry  

PubMed Central

Neuropeptides are often released into circulatory fluid (hemolymph) to act as circulating hormones and regulate many physiological processes. However, the detection of these low-level peptide hormones in circulation is often complicated by high salt interference and rapid degradation of proteins and peptides in crude hemolymph extracts. In this study, we systematically evaluated three different neuropeptide extraction protocols and developed a simple and effective hemolymph preparation method suitable for MALDI MS profiling of neuropeptides by combining acid-induced abundant protein precipitation/depletion, ultrafiltration, and C18 micro-column desalting. In hemolymph samples collected from crab Cancer borealis several secreted neuropeptides have been detected, including members from at least five neuropeptide families, such as RFamide, allatostatin, orcokinin, tachykinin-related peptide (TRP), and crustacean cardioactive peptide (CCAP). Furthermore, two TRPs were detected in the hemolymph collected from food-deprived animals, suggesting the potential role of these neuropeptides in feeding regulation. In addition, a novel peptide with a Lys-Phe-amide C-terminus was identified and de novo sequenced directly from the Cancer borealis hemolymph sample. To better characterize the hemolymph peptidome, we also identified several abundant peptide signals in C. borealis hemolymph that were assigned to protein degradation products. Collectively, our study describes a simple and effective sample preparation method for neuropeptide analysis directly from crude crustacean hemolymph. Numerous endogenous neuropeptides were detected including both known ones and new peptides whose functions remain to be characterized.

Chen, Ruibing; Ma, Mingming; Hui, Limei; Zhang, Jiang; Li, Lingjun

2009-01-01

199

Null point of discrimination in crustacean polarisation vision.  

PubMed

The polarisation of light is used by many species of cephalopods and crustaceans to discriminate objects or to communicate. Most visual systems with this ability, such as that of the fiddler crab, include receptors with photopigments that are oriented horizontally and vertically relative to the outside world. Photoreceptors in such an orthogonal array are maximally sensitive to polarised light with the same fixed e-vector orientation. Using opponent neural connections, this two-channel system may produce a single value of polarisation contrast and, consequently, it may suffer from null points of discrimination. Stomatopod crustaceans use a different system for polarisation vision, comprising at least four types of polarisation-sensitive photoreceptor arranged at 0, 45, 90 and 135 deg relative to each other, in conjunction with extensive rotational eye movements. This anatomical arrangement should not suffer from equivalent null points of discrimination. To test whether these two systems were vulnerable to null points, we presented the fiddler crab Uca heteropleura and the stomatopod Haptosquilla trispinosa with polarised looming stimuli on a modified LCD monitor. The fiddler crab was less sensitive to differences in the degree of polarised light when the e-vector was at -45 deg than when the e-vector was horizontal. In comparison, stomatopods showed no difference in sensitivity between the two stimulus types. The results suggest that fiddler crabs suffer from a null point of sensitivity, while stomatopods do not. PMID:24737768

How, Martin J; Christy, John; Roberts, Nicholas W; Marshall, N Justin

2014-07-15

200

Discovery and Functional Study of a Novel Crustacean Tachykinin Neuropeptide  

PubMed Central

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 gastric mill (food chewing) and 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 colocalized in the C. sapidus brain. Lastly, our electrophysiological studies show that bath-applied CalsTRP and CabTRP Ia each activate 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.

2011-01-01

201

Recrudescence mechanisms and gene expression profile of the reproductive tracts from chickens during the molting period.  

PubMed

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. PMID:24098561

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

2013-01-01

202

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

203

ENVIRONMENT, HEALTH, AND BEHAVIOR Effects of High Zinc Diets Using Zinc Propionate on Molt Induction, Organs, and Postmolt Egg Production and Quality in Laying Hens  

Microsoft Academic Search

This study was conducted to determine the ability of an alternative salt form of 1% Zn, Zn propionate, to induce molt in 66-wk-old hens. The hens were ran- domly assigned to 4 treatment groups of 27 or 28 birds each: a) molted conventionally by feed withdrawal, b) 1% Zn as Zn acetate, c) 1% Zn as Zn propionate, or d)

S. Y. Park; S. G. Birkhold; L. F. Kubena; D. J. Nisbet; S. C. Ricke

204

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

205

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

206

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

PubMed

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. PMID:18048285

Ungerer, Petra; Scholtz, Gerhard

2008-02-22

207

Aspartic proteinases in the digestive tract of marine decapod crustaceans.  

PubMed

Decapod crustaceans synthesize highly active proteolytic enzymes in the midgut gland and release at least a part of them into the stomach where they facilitate the first step in peptide hydrolysis. The most common proteinases in the gastric fluid characterized so far are serine proteinases, that is, trypsin and chymotrypsin. These enzymes show highest activities at neutral or slightly alkaline conditions. The presence of acid proteinases, as they prevail in vertebrates, has been discussed contradictorily yet in invertebrates. In this study, we show that acid aspartic proteinases appear in the gastric fluid of several decapods. Lobsters Homarus gammarus showed the highest activity with a maximum at pH 3. These activities were almost entirely inhibited by pepstatin A, which indicates a high share of aspartic proteinases. In other species (Panulirus interruptus, Cancer pagurus, Callinectes arcuatus and Callinectes bellicosus), proteolytic activities were present at acid conditions but were distinctly lower than in H. gammarus. Zymograms at pH 3 showed in each of the studied species at least one, but mostly two-four bands of activity. The apparent molecular weight of the enzymes ranged from 17.8 to 38.6 kDa. Two distinct bands were identified which were inhibited by pepstatin A. Acid aspartic proteinases may play an important role in the process of extracellular digestion in decapod crustaceans. Activities were significantly higher in clawed lobster than in spiny lobster and three species of brachyurans. Therefore, it may be suggested that the expression of acid proteinases is favored in certain groups and reduced in others. PMID:16788916

Navarrete del Toro, María de Los Angeles; García-Carreño, Fernando; López, Manuel Díaz; Celis-Guerrero, Laura; Saborowski, Reinhard

2006-08-01

208

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

209

Requirement of sterols in the life cycle of the nematode Caenorhabditis elegans  

Microsoft Academic Search

The nematode Caenorhabditis elegans represents an excellent model for studying many aspects of sterol function on the level of a whole organism. Recent studies show that especially two processes in the life cycle of the worm, dauer larva formation and molting, depend on sterols. In both cases, cholesterol or its derivatives seem to act as hormones rather than being structural

Eugeni V. Entchev; Teymuras V. Kurzchalia

2005-01-01

210

The influence of insect juvenile hormone agonists on metamorphosis and reproduction in estuarine crustaceans.  

PubMed

Comparative developmental and reproductive studies were performed on several species of estuarine crustaceans in response to three juvenile hormone agonists (pyriproxyfen, methoprene and fenoxycarb). Larval development of the grass shrimp, Palaemonetes pugio, was greater than two orders of magnitude more sensitive to disruption by methoprene and fenoxycarb than was embryonic development. Developing larvae of the mud crab, Rhithropanopeus harrisii, exhibited reduced metamorphic success at lower concentrations of methoprene and pyriproxyfen than grass shrimp larvae. These responses suggest that the more rigidly controlled metamorphic process in crabs is more sensitive to compounds acting as endocrine disruptors than is the more flexible metamorphic pattern in shrimp. The final crab larval stage, the megalopa, was more sensitive to methoprene and fenoxycarb exposure than earlier zoeal stages. Mud crab larvae exposed to fenoxycarb had reduced biomass and lipid content, particularly triglycerides and sterols. Concentrations of fenoxycarb which reduced the reproductive capacity in single life-cycle exposures of the estuarine mysid, Americamysis bahia, were similar to those concentrations which inhibited metamorphosis in grass shrimp. Juvenile mysids released by exposed adults and reared through maturation without further exposure produced fewer young and had altered sex ratios (lower percentages of males) at lower parental-exposure concentrations than directly affected parental reproduction. These transgenerational responses may well be a product of irreversible effects during developmental exposures which become apparent following maturation and initiation of reproduction. These findings support using a functional approach as an appropriate screening procedure to evaluate potential environmental endocrine-disrupting chemicals in aquatic environments. PMID:21676750

McKenney, Charles L

2005-01-01

211

EFFECTS OF HOUSING SYSTEMS ON PRODUCTIVE PERFORMANCE OF COMMERCIAL LAYERS FOLLOWING INDUCED MOLTING BY ALUMINIUM OXIDE SUPPLEMENTATION  

Microsoft Academic Search

The project was carried out to compare the performance of molted layers by aluminium oxide supplementation in cages and on litter floor system. Seventy two Single Comb White Leghorn commercial layers (60 weeks old) were divided into six experimental units of 12 layers each. These experimental units were randomly divided into two groups, each consisting of three experimental units, one

M. YOUSAF; N. AHMAD

212

Plasma biochemistry values in emperor geese (Chen canagica) in Alaska: comparisons among age, sex, incubation, and molt.  

USGS Publications Warehouse

Reduced populations of emperor geese (Chen canagica), a Bering Sea endemic, provided the need to assess plasma biochemistry values as indicators of population health. A precursory step to such an investigation was to evaluate patterns of variability in plasma biochemistry values among age, sex, and reproductive period. Plasma from 63 emperor geese was collected on their breeding grounds on the Yukon-Kuskokwim Delta in western Alaska, USA. The geese sampled included 18 incubating adult females captured, in mid June, on their nests by using bow nets, and 30 adults and 15 goslings captured in corral traps in late July and early August, when the adults were molting their wing feathers and the goslings were 5-6 weeks old. Plasma was evaluated for 15 biochemical parameters, by comparing results among age, sex, and sampling period (incubation versus wing-feather molt). Ten of the 15 biochemical parameters assayed differed among adults during incubation, the adults during molt, and the goslings at molt, whereas sex differences were noted in few parameters.

Franson, J. C.; Hoffman, D. J.; Schmutz, J. A.

2009-01-01

213

Plasma biochemistry values in emperor geese (Chen canagica) in Alaska: comparisons among age, sex, incubation, and molt.  

PubMed

Reduced populations of emperor geese (Chen canagica), a Bering Sea endemic, provided the need to assess plasma biochemistry values as indicators of population health. A precursory step to such an investigation was to evaluate patterns of variability in plasma biochemistry values among age, sex, and reproductive period. Plasma from 63 emperor geese was collected on their breeding grounds on the Yukon-Kuskokwim Delta in western Alaska, USA. The geese sampled included 18 incubating adult females captured, in mid June, on their nests by using bow nets, and 30 adults and 15 goslings captured in corral traps in late July and early August, when the adults were molting their wing feathers and the goslings were 5-6 weeks old. Plasma was evaluated for 15 biochemical parameters, by comparing results among age, sex, and sampling period (incubation versus wing-feather molt). Ten of the 15 biochemical parameters assayed differed among adults during incubation, the adults during molt, and the goslings at molt, whereas sex differences were noted in few parameters. PMID:19569480

Franson, J Christian; Hoffman, David J; Schmutz, Joel A

2009-06-01

214

Applying fenoxycarb at the penultimate instar triggers an additional ecdysteroid surge and induces perfect extra larval molting in the silkworm  

Microsoft Academic Search

When the juvenile hormone analog fenoxycarb was topically applied to the silkworm Bombyx mori at the beginning of the 3rd or 4th (penultimate) instar, an extra larval molt was induced. The 5th instar period was shortened to about 5 days and the extra 6th instar ranged from 8 to more than 20 days, depending on the dose applied. Starvation before

Manabu Kamimura; Makoto Kiuchi

2002-01-01

215

Growth versus molting time of caterpillars as a function of temperature, nutrient concentration and the phenolic rutin  

Microsoft Academic Search

A factorial experiment tested the effects of varying nutrient concentration (normal versus diluted), presence or absence of the phenolic allelochemical rutin and daytime temperature (20, 25 and 30° C) on growth, molting and food utilization efficiencies of tobacco hornworms (Manduca sexta). Two of the utilization efficiencies (approximate digestibility and efficiency of conversion of ingested food) were unaffected by temperature; the

Nancy E. Stamp

1990-01-01

216

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...

217

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...

218

78 FR 9327 - Hawaii Crustacean Fisheries; 2013 Northwestern Hawaiian Islands Lobster Harvest Guideline  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 665 RIN 0648-XC453 Hawaii Crustacean Fisheries; 2013 Northwestern Hawaiian Islands Lobster Harvest Guideline AGENCY: National Marine Fisheries Service...

2013-02-08

219

76 FR 4551 - Hawaii Crustacean Fisheries; 2011 Northwestern Hawaiian Islands Lobster Harvest Guideline  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 665 RIN 0648-XA159 Hawaii Crustacean Fisheries; 2011 Northwestern Hawaiian Islands Lobster Harvest Guideline AGENCY: National Marine Fisheries Service...

2011-01-26

220

REPRODUCTIVE AND DEVELOPMENTAL SCREENING PROTOCOLS FOR ENDOCRINE DISRUPTORS USING ESTUARINE CRUSTACEANS  

EPA Science Inventory

The objective of this research is to develop in vivo screening protocols for endocrine disruption in marine crustaceans, invertebrates of ecological and economic importance. A series of comparative developmental and reproductive studies were performed on several species of estuar...

221

THE INFLUENCE OF INSECT JUVENILE HORMONE AGONISTTS ON METAMORPHOSIS AND REPRODUCTION IN ESTUARINE CRUSTACEANS  

EPA Science Inventory

Comparative developmental and reproductive studies were performed on several species of estuarine crustaceans in response to three juvenile hormone agonists (JHAs) (methoprene, fenoxycarb, and pyriproxyfen). Larval development of the grass shrimp, Palaemonetes pugio, was greater ...

222

Developmental changes in the embryo, pronymph, and first molt of the scorpion Centruroides vittatus (scorpiones: buthidae).  

PubMed

For the first time the scanning electron microscope was used to compare developmental changes in scorpion embryos and the first and second stadia. In the buthid species of this study, Centruroides vittatus, and all other scorpions, the newborn climb up on their mother's back and remain there without feeding for several days. At this location, they undergo their first molt and in a few days they disperse, fully capable of foraging in the terrestrial environment. The results here support earlier suggestions that the first stadium (pronymph) is a continuation and extension of embryological development. The first molt results in a nymph with exoskeletal features much like those in the adult. In the first molt the metasoma becomes relatively longer, and the sting (aculeus) becomes sharp and functional. The metasomal segments are modified for dorsal flexion and sting use. The embryos and the pronymphs have spiracles that open into an invagination near the posterior margin of flap-like abdominal plates in segments 4-7 of the ventral mesosoma. The second instars have spiracles that lead to book lungs farther anterior in sternites. Tubular legs with cylindrical segments in embryos and pronymphs become more sculptured and oval in the transverse plane. Each leg in the pronymph has a blunt, cup-shaped tip while distal claws (ungues, dactyl) are present in the second instar and subsequent stages. There are some sharp bristles and primordial sensilla in the pronymphs, but the second stadium has adult-like surface features: rows of knobs or granulations (carinae), serrations on the inner surfaces of cheliceral and pedipalpal claws, filtering hairs at the mouthparts, peg sensilla on the pectines, and mechano- and chemoreceptor sensilla on the body and appendages. Scorpion embryos and pronymphs have some structures like fossil scorpions thought to have been aquatic. There is a gradual development of features that appear to be terrestrial adaptations. Evidence is provided for the formation of the sternum from third and fourth leg coxal primordia and possibly from the first abdominal segment. This study is the first to provide evidence for a forward shift of the gonopore along with other structures in the anterior abdomen. PMID:15549700

Farley, Roger D

2005-07-01

223

A structural and functional comparison of nematode and crustacean PDH-like sequences.  

PubMed

The elucidation of the whole genome of the nematode Caenorhabditis elegans allowed for the identification of ortholog genes belonging to the pigment dispersing hormone/factor (PDH/PDF) peptide family. Members of this peptide family are known from crustaceans, insects and nematodes and seem to exist exclusively in ecdysozoans where they play a role in different processes, ranging from the dispersion of integumental and eye (retinal) pigments in decapod crustaceans to circadian rhythms in insects and locomotion in C. elegans. Two pdf genes (pdf-1 and pdf-2) encoding three different peptides: PDF-1a, PDF-1b and PDF-2 have been identified in C. elegans. These three C. elegans PDH-like peptides are similar but not identical in primary structure to PDHs from decapod crustaceans. We investigate whether this divergence has an influence on the pigment dispersing function of the peptides in a decapod crustacean, namely the shrimp Palaemon pacificus. We show that C. elegans PDF-1a and b peptides display cross-functional activity by dispersing pigments in the epithelium of P. pacificus at physiological doses. Moreover, by means of a comparative amino acid sequence analysis of nematode and crustacean PDH-like peptides, we can pinpoint several potentially important residues for eliciting pigment dispersing activity in decapod crustaceans. Although there is no sequence information on a receptor for PDH in decapod crustaceans, we postulate that there is general conservation of the PDH/PDF signaling system based on structural similarities of precursor proteins and receptors (including those from a branchiopod crustacean and from C. elegans). PMID:22115566

Meelkop, E; Marco, H G; Janssen, T; Temmerman, L; Vanhove, M P M; Schoofs, L

2012-03-01

224

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

225

Fine scale movements and habitat use of black brant during the flightless Wing Molt in Arctic Alaska  

USGS Publications Warehouse

Thousands of Black Brant (Branta bernicla nigricans) migrate annually to the Teshekpuk Lake Special Area (TLSA), Alaska, to undergo the flightless wing molt on tundra lakes and wetlands. GPS transmitters were attached to Brant over two summers (2007â€"2008) to examine patterns of movement and habitat use of molting Brant, including variation by habitat type, year and body mass. Molting Brant were located an average of 31 ±1 m (SE) from shore and this distance did not vary across any of the explanatory variables. Brant moved an average of 123 ±3 m hr -1 while flightless. Movement rates varied by year, averaging 22 ±12 m hr -1 faster in 2008, and across habitat types, averaging 22 ±13 m hr -1 faster in inland versus coastal and estuarine habitats. Two kernel home ranges were estimated: entire home range, which encompassed the complete 95% probability contour, and shoreline home range, which included only shoreline areas used by molting Brant. Entire home range (x bar = 15.1 ±2.2 km 2) was negatively correlated with body mass, suggesting that heavier individuals have more body reserves to contribute to feather growth and thereby require less food and smaller home ranges. Conversely, shoreline home range (x bar = 4.3 ±0.6 km 2) did not vary by body mass, but rather by habitat type, being larger in estuarine habitats. The complex shorelines and numerous deltaic islands of estuarine habitats offer more shoreline per area than either coastal or inland habitats. Brant appear to have limited ability to adjust their home range size or forage further from shore in response to variable food resources across years or habitats, instead altering their movement rate. Given this apparent lack of behavioral flexibility, Brant may be sensitive to development-related disturbances or habitat losses at molt sites in the TLSA.

Lewis, Tyler L.; Flint, Paul L.; Derksen, Dirk V.; Schmutz, Joel A.

2011-01-01

226

A crustacean nitric oxide synthase expressed in nerve ganglia, Y-organ, gill and gonad of the tropical land crab, Gecarcinus lateralis.  

PubMed

NO signaling is involved in many physiological processes in invertebrates. In crustaceans, it plays a role in the regulation of the nervous system and muscle contraction. Nested reverse transcription-polymerase chain reaction (RT-PCR) and 5' and 3' rapid amplification of cDNA ends (RACE) PCR generated a full-length cDNA sequence (3982 bp) of land crab NO synthase (Gl-NOS) from molting gland (Y-organ) and thoracic ganglion mRNA. The open reading frame encoded a protein of 1199 amino acids with an estimated mass of 135 624 Da. Gl-NOS had the highest sequence identity with insect NOS. The amino acid sequences for binding heme and tetrahydrobiopterin in the oxygenase domain, binding calmodulin and binding FMN, FAD and NADPH in the reductase domain were highly conserved. Gl-NOS had single amino acid differences in all three highly conserved FAD-binding sequences, which distinguished it from other NOS sequences. RT-PCR showed that the Gl-NOS mRNA was present in testis, ovary, gill, eyestalk neural ganglia, thoracic ganglion and Y-organ. NOS mRNA varied between preparations of Y-organ, thoracic ganglion and gill, while NOS mRNA was at consistently high levels in the ovary, testis and eyestalk ganglia. Immunohistochemistry confirmed that the Gl-NOS protein was expressed in Y-organ, ovary and gill. These results suggest that NOS has functions in addition to neuromodulation in adults, such as regulating or modulating ecdysteroid synthesis in the Y-organ. PMID:15235013

Kim, Hyun-Woo; Batista, Luisa A; Hoppes, Jodi L; Lee, Kara J; Mykles, Donald L

2004-07-01

227

Population variation in isotopic composition of shorebird feathers: Implications for determining molting grounds  

USGS Publications Warehouse

Stable isotope analyses have revolutionized the study of migratory connectivity. However, as with all tools, their limitations must be understood in order to derive the maximum benefit of a particular application. The goal of this study was to evaluate the efficacy of stable isotopes of C, N, H, O and S for assigning known-origin feathers to the molting sites of migrant shorebird species wintering and breeding in Argentina. Specific objectives were to: 1) compare the efficacy of the technique for studying shorebird species with different migration patterns, life histories and habitat-use patterns; 2) evaluate the grouping of species with similar migration and habitat use patterns in a single analysis to potentially improve prediction accuracy; and 3) evaluate the potential gains in prediction accuracy that might be achieved from using multiple stable isotopes. The efficacy of stable isotope ratios to determine origin was found to vary with species. While one species (White-rumped Sandpiper, Calidris fuscicollis) had high levels of accuracy assigning samples to known origin (91% of samples correctly assigned), another (Collared Plover, Charadrius collaris) showed low levels of accuracy (52% of samples correctly assigned). Intra-individual variability may account for this difference in efficacy. The prediction model for three species with similar migration and habitat-use patterns performed poorly compared with the model for just one of the species (71% versus 91% of samples correctly assigned). Thus, combining multiple sympatric species may not improve model prediction accuracy. Increasing the number of stable isotopes in the analyses increased the accuracy of assigning shorebirds to their molting origin, but the best combination - involving a subset of all the isotopes analyzed - varied among species.

Torres-Dowdall, J.; Farmer, A. H.; Bucher, E. H.; Rye, R. O.; Landis, G.

2009-01-01

228

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

229

Crustacean fish parasites from Segara Anakan Lagoon, Java, Indonesia.  

PubMed

The present study is the first investigation on ectoparasites of commercial important fish from Segara Anakan, a brackish water lagoon located at the southern coast of Java, Indonesia. Eight economically important marine fish species (Mugil cephalus, Siganus javus, Scatophagus argus, Caranx sexfasciatus, Lutjanus johnii, Eleutheronema tetradactylum, Johnius coitor, and Epinephelus coioides) were examined for crustacean parasites. Prevalence and intensity data for each parasite species are given, together with an analysis of the origin and possible transmission pathways. A highly divers copepod fauna consisting of 23 different species and two isopods was found. All fish species were at least infested with two copepod species, with the exception of L. johnii, S. argus, and M. cephalus. With seven and six species, respectively, they harboured the most species-rich ectoparasite fauna. The copepods Ergasilus sp. 3 and Caligus acanthopagri on S. argus showed the highest prevalence (78.6) and intensity [17.8 (1-233) and 5.3 (1-22)] of infestation. The recorded parasite fauna is represented by marine, brackish water, and probably also freshwater components. The brackish water environment of Segara Anakan does not prevent disease outbreaks due to parasitic copepods by preventing pathogenic marine or freshwater species to enter the lagoon. This might cause fish health problems if the Segara Anakan Lagoon would be developed for finfish mariculture in future. PMID:17219222

Yuniar, Asri T; Palm, Harry W; Walter, Thorsten

2007-05-01

230

Crustacean muscle plasticity: molecular mechanisms determining mass and contractile properties.  

PubMed

Two crustacean models for understanding molecular mechanisms of muscle plasticity are reviewed. Metabolic changes underlying muscle protein synthesis and degradation have been examined in the Bermuda land crab, Gecarcinus lateralis. During proecdysis, the claw closer muscle undergoes a programmed atrophy, which results from a highly controlled breakdown of myofibrillar proteins by Ca(2+)-dependent and, possibly, ATP/ubiquitin-dependent proteolytic enzymes. The advantage of this model is that there is neither fiber degeneration nor contractile-type switching, which often occurs in mammalian skeletal muscles. The second model uses American lobster, Homarus americanus, to understand the genetic regulation of fiber-type switching. Fibers in the claw closer muscles undergo a developmentally-regulated transformation as the isomorphic claws of larvae and juveniles differentiate into the heteromorphic cutter and crusher claws of adults. This switching occurs at the boundary between fast- and slow-fiber regions, and thus the transformation of a specific fiber is determined by its position within the muscle. The ability to predict fiber switching can be exploited to isolate and identify putative master regulatory factors that initiate and coordinate the expression of contractile proteins. PMID:9253174

Mykles, D L

1997-07-01

231

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

2012-01-01

232

Four parasitic Crustacean species from marine fishes of Turkey.  

PubMed

The aim of this work was to present a preliminary knowledge of the parasitic copepods of marine fish of Turkey. In this study, four parasitic crustaceans were reported from five different fish species found in Turkish seas: Lepeophtheirus europaensis (Zeddam, Berrebi, Renaud, Raibaut & Gabrion, 1988) was found on the gills of the European flounder, Platichtys flesus (Linnaeus, 1758 (Pleuronectidae); Nerocila bivittata (Risso, 1816) on caudal peduncles of east Atlantic peacock wrasse, Symphodus tinca (Linnaeus, 1758) (Labridae); Ceratothoa oestroides (Risso, 1826), on the mouth base of European pilchard, Sardina pilchardus (Walbaum, 1792) (Clupeidae); Anilocra physodes (Linnaeus, 1758), on the body surface of gilthead seabreams, Sparus aurata Linnaeus, 1758 (Sparidae) and on horse mackerel, Trachurus trachurus (Linnaeus, 1758) (Carangidae). Also, a list of the parasitic copepods previously reported from marine fishes of Turkey since 1931 is given, with a new report of the host species, the localities where they were collected and the corresponding authors. At the present time, 23 parasitic copepods have been recorded from 25 host fish of Turkish coasts. Lepeophtheirus europaensis Zeddam, Berrebi, Renaud, Raibaut & Gabrion, 1988 was reported for the first time in Turkish coastal waters. PMID:17471420

Oguz, Mehmet Cemal; Oktener, Ahmet

2007-01-01

233

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

234

Different types of blockade of crustacean acetylcholine-induced currents.  

PubMed Central

The voltage dependence, concentration dependence, and agonist dependence of blocking and unblocking produced by anticholinergic agents on the ionophoretically activated cholinergic currents of the lobster gastric mill 1 (g.m.1) muscle were examined. Although the ionophoretic technique provides only qualitative information as to blocking mechanisms it is useful in revealing slow components of the blocking action of some drugs. At least two qualitatively different types of voltage-dependent block of the crustacean cholinergic currents were observed. For pempidine, mecamylamine and decamethonium (also chlorisondamine: Lingle, 1983), a slowly developing voltage-dependent block was produced that led to the formation of a stable-blocked state. Recovery from this stable-blocked state is largely dependent on subsequent application of agonist. In contrast, recovery from the voltage-dependent block produced by QX-222, atropine, procaine and curare either proceeds independently of agonist application or occurs too rapidly to be observed by the present methods. Blockade by hexamethonium reveals anomalous voltage dependence, being enhanced over some voltages and relieved with additional hyperpolarization. Blockade by trimetaphan is largely independent of membrane potential except at higher concentrations.

Lingle, C

1983-01-01

235

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

236

Ultrastructural and cytological changes in the muscle fibers of the pectoralis of the giant Canada goose ( Branta canadensis maxima ) in disuse atrophy during molt  

Microsoft Academic Search

Adult male Branta canadensis maxima were collected from a nonmigratory feral population during their premolt, molt and postmolt phases. Lean dry weight of the pectoralis muscle decreased significantly (p=0.0001) during molt, as a result of disuse atrophy. Histochemical analysis revealed that the region of the pectoralis muscle sampled consisted of Red (fast-twitch oxidative-glycolytic) and White (fast-twitch glycolytic) muscle fiber types,

B. W. C. Rosser; J. C. George

1987-01-01

237

Organochlorinated contaminants in decapod crustaceans from the coasts of Brittany and Normandy (France).  

PubMed

The contamination and distribution of organochlorinated compounds were considered in three crustacean species (edible crab, Cancer pagurus; spider crab, Maja brachydactyla; velvet swimming crab, Necora puber) from five sites along the coasts of Brittany and Normandy (Western and North-Western France). PCBs (16 single congeners), pp'-DDE and HCB were measured in hepatopancreas, gonads and muscle: in all, 175 samples were analysed. The spider crab was the only species found in the five sampling sites, thus enabling comparison between areas. Specimens from Antifer were much more contaminated (summation operator 16 PCBs in hepatopancreas=2000-4000 ng g(-1) dry weight) than those from other sites (50-1000 ng g(-1) d.w.). Among all the three species, the spider crab appeared more contaminated by PCBs than the edible crab, by a factor 2-3, probably in relation with specific differences in their life cycle. There was no difference due to the gender of the species. Within the different analysed tissues, contamination levels increased from muscle to gonads and hepatopancreas in relation with the fat content. A very similar PCB composition was observed in all samples, PCB fingerprints being characterised by the relative importance of the more persistent PCB congeners: CB153, 138, 180, 187, and 118. Finally, these results were compared to recent food regulations first of maximum marker PCB intake and secondly of maximum dioxin-like PCB intake. By considering the muscle, all samples were far below the regulatory limits; for hepatopancreas and gonads, however, some samples were unfit for human consumption. PMID:17223177

Bodin, N; Abarnou, A; Le Guellec, A-M; Loizeau, V; Philippon, X

2007-04-01

238

The non-native seaweed Asparagopsis armata supports a diverse crustacean assemblage.  

PubMed

This is the first study describing the crustacean fauna associated to Asparagopsis armata, a non-native, red seaweed widely distributed along western Mediterranean coasts. First found in Australia and New Zealand, it was introduced naturally through the Strait of Gibraltar and rapidly spread out. A one-year spatio-temporal study (Feb 08-Feb 09) was carried out in the Strait of Gibraltar to characterize the spatio-temporal patterns of the associated crustacean fauna. Maximum biomass of A. armata was measured during April-June, whereas the maximum crustacean abundances were registered from June-October. In total 41 crustacean species were identified. The caprellid Caprella penantis, traditionally associated to non-polluted areas, was more abundant on Tarifa Island (higher values of dissolved oxygen and pH) than in Algeciras (lower oxygen and pH). The gammarid Podocerus variegatus was dominant in Algeciras Bay while Hyale schmidti and Apherusa mediterranea were the most abundant on Tarifa Island. Among isopods, Synisoma nadejda was only found on Tarifa Island. When compared with literature of native algae of the intertidal and shallow sublittoral, the species richness of associated crustaceans was similar in A. armata and the natives. Very little is known about the influence of this algae on altering marine communities, so complete faunistic studies dealing with other groups such as polychaetes or molluscs are necessary to properly address biogeographical, ecological and management programmes dealing with this non-native species. PMID:21367448

Pacios, I; Guerra-García, J M; Baeza-Rojano, E; Cabezas, M P

2011-05-01

239

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

240

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

2004-07-01

241

Ensuring crustacean product quality in the post-harvest phase.  

PubMed

Recent studies of the fisheries for the Norway lobster, Nephrops norvegicus (L.), have illustrated the negative effects of pathogens and of the physiological stresses of capture processes on the exploitation of live animals and their products, and have identified mitigating measures. Firstly, having established that trawl capture of N. norvegicus is highly stressful, but that these animals have powerful physiological mechanisms of recovery, procedures for on-board recovery of animals destined for vivier transport to distant European markets have been implemented commercially, with significant improvements in survival rates. Such procedures also mitigate against the initiation of a stress-induced muscle necrosis. Secondly, measurements of post-mortem autolytic and spoilage processes have identified the existence of a post-capture 'handling window' of several hours which allows the whole or tailed products to be preserved, by icing or freezing, without detriment to quality. Commercial consortia of Scottish fishermen are exploiting this opportunity to extend product shelf-life by freezing at sea within this handling window. Thirdly, the well-documented infections of Scottish N. norvegicus populations by the dinoflagellate Hematodinium sp. not only provide examples of pathogen-induced mortality, but also have effects on post-harvest products including vivier transport losses and changes in post-mortem degradation leading to earlier organoleptic rejection. Under commercial conditions these effects can be mitigated by post-capture visual screening, but only during the periods of peak patent infection when parasitised animals are visually identifiable. Wider implementation of such mitigating procedures during the harvesting of wild-caught crustaceans will contribute to a more sustainable exploitation of these valuable marine resources. PMID:22433999

Neil, Douglas M

2012-06-01

242

Comparative phylogeography of two North American 'glacial relict' crustaceans.  

PubMed

The Pleistocene glaciations represent the most recent and dramatic series of habitat changes since the Cretaceous. The impact of these events was particularly acute for aquatic taxa with poor powers of dispersal, but few organisms have evolutionary histories more intimately entwined with the advance and retreat of ice than the 'glacial relicts'. In this study, we used a mitochondrial gene, cytochrome c oxidase subunit I (COI), to examine and compare the phylogeographical structure of two glacial relict crustaceans (Limnocalanus macrurus and members of the Mysis relicta species group) across North America. In both cases, we found a sharp phylogenetic division between populations from inland lakes formed during glacial retreat, and arctic lakes isolated from polar seas via isostatic rebound. However, the depth of this phylogenetic partition varied between taxa. In L. macrurus, nucleotide sequence divergence of 2.2% between these zones is consistent with its current status as a single morphologically variable species, but in Mysis the split occurred among recently described, morphologically conserved species, at a divergence of 8.2%. The disparity in the depth of divergence indicates a history of recurrent freshwater invasions from the arctic seas, in concordance with previous studies of Eurasian glacial relicts. However, we suggest further consideration of a largely overlooked explanation that could account for some of the discrepancies between molecular divergences and glaciation events. Many cladogenetic events could have occurred in arctic seas prior to the transition to inland waters, a possibility supported both by the complex physical and ionic history of arctic seas and by high marine and estuarine lineage diversity in the north. PMID:17107476

Dooh, R T; Adamowicz, S J; Hebert, P D N

2006-12-01

243

Control of body size by oxygen supply reveals size-dependent and size-independent mechanisms of molting and metamorphosis  

PubMed Central

Body size profoundly affects many aspects of animal biology, including metamorphosis, allometry, size-dependent alternative pathways of gene expression, and the social and ecological roles of individuals. However, regulation of body size is one of the fundamental unsolved problems in developmental biology. The control of body size requires a mechanism that assesses size and stops growth within a characteristic range of sizes. Under normal growth conditions in Manduca sexta, the endocrine cascade that causes the brain to initiate metamorphosis starts when the larva reaches a critical weight. Metamorphosis is initiated by a size-sensing mechanism, but the nature of this mechanism has remained elusive. Here we show that this size-sensing mechanism depends on the limited ability of a fixed tracheal system to sustain the oxygen supply to a growing individual. As body mass increases, the demand for oxygen also increases, but the fixed tracheal system does not allow a corresponding increase in oxygen supply. We show that interinstar molting has the same size-related oxygen-dependent mechanism of regulation as metamorphosis. We show that low oxygen tension induces molting at smaller body size, consistent with the hypothesis that under normal growth conditions, body size is regulated by a mechanism that senses oxygen limitation. We also found that under poor growth conditions, larvae may never attain the critical weight but eventually molt regardless. We show that under these conditions, larvae do not use the critical weight mechanism, but instead use a size-independent mechanism that is independent of the brain.

Callier, Viviane; Nijhout, H. Frederik

2011-01-01

244

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

245

Primary structures of decapod crustacean metallothioneins with special emphasis on freshwater and semi-terrestrial species.  

PubMed

Cadmium injections induced only a single form of metallothionein (MT) in the midgut gland of Potamon potamios, whereas the same treatment induced two isoforms in Astacus astacus. The only difference between the two latter isoforms was that one had an extra N-terminal methionine residue. MT from P. potamios showed structural differences from other decapod crustacean MTs. It contained a Gly-Thr motif at positions 8 and 8a, which had previously been found only in certain vertebrate and molluscan MTs. Furthermore P. potamios MT contained two to three times as many glutamic acid residues as normally found in decapod crustacean MT. The primary structure of MT from the freshwater crayfish A. astacus showed a high degree of sequence identity with MT from other decapod crustaceans, especially the marine astacidean Homarus americanus, although two valine residues were unexpectedly found at positions 8 and 21, where lysine residues are normally found. PMID:8921011

Pedersen, S N; Pedersen, K L; Højrup, P; Depledge, M H; Knudsen, J

1996-11-01

246

Gene expression profiling of cuticular proteins across the moult cycle of the crab Portunus pelagicus  

PubMed Central

Background Crustaceans represent an attractive model to study biomineralization and cuticle matrix formation, as these events are precisely timed to occur at certain stages of the moult cycle. Moulting, the process by which crustaceans shed their exoskeleton, involves the partial breakdown of the old exoskeleton and the synthesis of a new cuticle. This cuticle is subdivided into layers, some of which become calcified while others remain uncalcified. The cuticle matrix consists of many different proteins that confer the physical properties, such as pliability, of the exoskeleton. Results We have used a custom cDNA microarray chip, developed for the blue swimmer crab Portunus pelagicus, to generate expression profiles of genes involved in exoskeletal formation across the moult cycle. A total of 21 distinct moult-cycle related differentially expressed transcripts representing crustacean cuticular proteins were isolated. Of these, 13 contained copies of the cuticle_1 domain previously isolated from calcified regions of the crustacean exoskeleton, four transcripts contained a chitin_bind_4 domain (RR consensus sequence) associated with both the calcified and un-calcified cuticle of crustaceans, and four transcripts contained an unannotated domain (PfamB_109992) previously isolated from C. pagurus. Additionally, cryptocyanin, a hemolymph protein involved in cuticle synthesis and structural integrity, also displays differential expression related to the moult cycle. Moult stage-specific expression analysis of these transcripts revealed that differential gene expression occurs both among transcripts containing the same domain and among transcripts containing different domains. Conclusion The large variety of genes associated with cuticle formation, and their differential expression across the crustacean moult cycle, point to the complexity of the processes associated with cuticle formation and hardening. This study provides a molecular entry path into the investigation of the gene networks associated with cuticle formation.

Kuballa, Anna V; Merritt, David J; Elizur, Abigail

2007-01-01

247

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

248

The molt/intermolt cycle in the epidermis and other tissues of an insect Calpodes ethlius(Lepidoptera, Hesperiidae).  

PubMed

Tissue responses to the brain and prothoracic glands divide the 5th larval stage of Calpodes into three phases of development, characterized by growth, larval syntheses and pupal syntheses. Tissue specific patterns in the timing of nuclear events fall into one of two categories. In both, the cell number is determined mainly before the 4th to 5th ecdysis. Epidermal cells divide during the second phase coincidentally with an elevated rate of larval cuticle deposition, but in other tissues nuclear replication occurs without division during the first phase so that the cells are polyploid by the time they begin their massive larval syntheses. PMID:18631509

Locke, M

1970-01-01

249

CHANGES IN NUCLEIC ACIDS OVER THE MOLT CYCLE IN RELATION TO FOOD AVAILABILITY AND TEMPERATURE IN HOMARUS AMERICANUS POSTLARVAE  

EPA Science Inventory

Postlarval lobsters Homarus americanus Milne Edwards hatched from three females collected in 1989 fr m Block Island Sound, Rhode Island were reared individually in the laboratory under nine treatment combinations of temperature (15, 18 and 200C) and feeding(starved, low ration, a...

250

Freshwater decapod crustaceans (Palaemonidae, Cambaridae) of the Savannah River Plant, South Carolina  

Microsoft Academic Search

Decapod crustaceans (specifically crayfishes and freshwater shrimps) are quite numerous in the drainages of the southeastern United States and occupy an extremely important niche in aquatic systems. As predators they act as disturbance components on benthic freshwater communities and may serve an integral position in the early stages of detrital decomposition. They constitute an important prey item in the diets

H. H. Hobbs; J. H. Thorp; G. E. Anderson

2011-01-01

251

Hypothesis for heritable, anti-viral immunity in crustaceans and insects  

Microsoft Academic Search

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

Timothy W Flegel; Klong Luang

2009-01-01

252

[Crustaceans associated to macroalgae in Bajo Pepito, Isla Mujeres, Mexican Caribbean].  

PubMed

Crustaceans associated with macroalgae were collected for one year by scuba diving in Bajo Pepito, Isla Mujeres, mexican Caribbean. A total of 148 organisms were found: three orders, 11 families, 18 genera and 19 species in nine types of associations. The order with highest abundance was Isopoda (112), followed by Amphipoda (20) and Decapoda (16). PMID:11354943

Campos Vázquez, C

2000-01-01

253

A morphological approach for relating decapod crustacean cephalothorax shape with distribution in the water column  

Microsoft Academic Search

Cephalothorax profiles for individuals of 18 decapod crustacean species were obtained from pictures of specimens captured using various experimental bottom trawls in the Mediterranean basin, at depths ranging from 200 to 4000 m in 2000 and 2002. Profiles were compared using the shape (outline) of the entire cephalothorax (including and excluding the rostrum). Principal component analysis (PCA) of the profiles, rostrum

F. Sardà; J. B. Company

2005-01-01

254

Occurrence of the autofluorescent pigment, lipofuscin, in polar crustaceans and its potential as an age marker  

Microsoft Academic Search

In crustaceans, the lack of reliable methods often prevents the determination of individual age. The quantification of the autofluorescent age pigment, lipofuscin, has revealed promising results in boreal and tropical species. We studied the presence of morphological lipofuscin and its possible application as an age marker in five Arctic and five Antarctic species, comprising decapods, amphipods and a euphausiid. Lipofuscin

Bodil A. Bluhm; Thomas Brey; Michael Klages; Wolf E. Arntz

2001-01-01

255

The embryonic development of the malacostracan crustacean Porcellio scaber (Isopoda, Oniscidea)  

Microsoft Academic Search

To examine the evolution of development and put it into a phylogenetic context, it is important to have, in addition to a\\u000a model organism like Drosophila, more insights into the huge diversity of arthropod morphologies. In recent years, the malacostracan crustacean Porcellio scaber Latreille, 1804 has become a popular animal for studies in evolutionary and developmental biology, but a detailed

Carsten Wolff

2009-01-01

256

POST-EXERCISE LACTATE PRODUCTION AND METABOLISM IN THREE SPECIES OF AQUATIC AND TERRESTRIAL DECAPOD CRUSTACEANS  

Microsoft Academic Search

Summary Aquatic and terrestrial crustaceans are dependent on both aerobic and anaerobic metabolism for energy production during exercise. Anaerobic energy production is marked by an accumulation of lactate in both muscle tissue and haemolymph, but the metabolic fate of lactate is not clear. Lactate recycling via gluconeogenesis and the potential role of carbonic anhydrase (CA) in supplying bicarbonate for the

RAYMOND P. HENRY; CHARLES E. BOOTH; FRANCOIS H. LALLIER; PATRICK J. WALSH

257

Paleozoic-Mesozoic crayfish from Antarctica: Earliest evidence of freshwater decapod crustaceans  

Microsoft Academic Search

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

Loren E. Babcock; Molly F. Miller; John L. Isbell; James W. Collinson; Stephen T. Hasiotis

1998-01-01

258

Experimental taphonomy of a decapod crustacean: Long-term data and their implications  

Microsoft Academic Search

Despite being a common element in many modern marine habitats, decapod crustaceans have a patchy yet long-ranging fossil record. While a strong susceptibility to decay early in the post-mortem history is generally acknowledged, specific controls on the preservation potential of this group are poorly understood. To aid in the full understanding of the details of the taphonomic process for this

Richard A. Krause; Karla Parsons-Hubbard; Sally E. Walker

259

Mass spectrometric evaluation of neuropeptidomic profiles upon heat stabilization treatment of neuroendocrine tissues in crustaceans  

PubMed Central

Tissue heat stabilization is a vital component in successful mammalian neuropeptidomic studies. Heat stabilization using focused microwave irradiation, conventional microwave irradiation, boiling, and treatment with the Denator Stabilizor T1 have all proven effective in arresting post-mortem protein degradation. Although research has reported the presence of protein fragments in crustacean hemolymph when protease inhibitors were not added to the sample, the degree to which postmortem protease activity affects neuropeptidomic tissue studies in crustacean species has not been investigated in depth. This work examines the need for Stabilizor T1 or boiling tissue stabilization methods for neuropeptide studies of Callinectes sapidus (blue crab) pericardial organ tissue. Neuropeptides in stabilized and non-stabilized tissue are extracted using acidified methanol or N,N-Dimethylformamide (DMF) and analyzed by MALDI-TOF and nanoLC-ESI-MS/MS platforms. Post-mortem fragments did not significantly affect MALDI analysis in the range m/z 650–1600, but observations in ESI MS/MS experiments suggest that putative post-mortem fragments can mask neuropeptide signal and add spectral complexity to crustacean neuropeptidomic studies. The impact of the added spectral complexity did not dramatically affect the number of detected neuropeptides between stabilized and non-stabilized tissues. However, it is prudent that neuropeptidomic studies of crustacean species include a preliminary experiment using the heat stabilization method to assess the extent of neuropeptide masking by larger, highly charged molecular species.

Sturm, Robert M.; Greer, Tyler; Woodards, Nicole; Gemperline, Erin; Li, Lingjun

2012-01-01

260

Insecticidal juvenile hormone analogs stimulate the production of male offspring in the crustacean Daphnia magna.  

PubMed Central

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 farnesoate, producing altered sex ratios of offspring. Daphnids were exposed chronically (3 weeks) to sublethal concentrations of methyl farnesoate, the JHA pyriproxyfen, and several nonjuvenoid chemicals to discern whether excess male offspring production is a generic response to stress or a specific response to juvenoid hormones. Only methyl farnesoate and pyriproxyfen increased the percentage of males produced by exposed maternal organisms. As previously reported with methyl farnesoate, acute exposure (24 hr) to either pyriproxyfen or the JHA methoprene caused oocytes maturing in the ovary to develop into males. We performed experiments to determine whether combined effects of a JHA and methyl farnesoate conformed better to a model of concentration addition (indicative of same mechanism of action) or independent joint action (indicative of different mechanisms of action). Combined effects conformed better to the concentration-addition model, although some synergy, of unknown etiology, was evident between the insecticides and the hormone. These experiments demonstrate that insecticidal JHAs mimic the action of the crustacean juvenoid hormone methyl farnesoate, resulting in the inappropriate production of male offspring. The occurrence of such an effect in the environment could have dire consequences on susceptible crustacean populations.

Olmstead, Allen W; LeBlanc, Gerald A

2003-01-01

261

Temporal and Spatial Patterns of Microhabitat Use by Fishes and Decapod Crustaceans in a Louisiana Estuary  

Microsoft Academic Search

We used a 1-m beam trawl to characterize microhabitat use by fishes and decapod crustaceans in monthly samples collected in Vermilion and West Cote Blanche bays in central coastal Louisiana. Randomized sampling within strata characterized the distributions of species, size-classes, and environmental conditions throughout the coastal bays. Microhabitats were characterized by salinity, temperature, dissolved oxygen, depth, distance from shore, substrate

Donald M. Baltz; Robert F. Jones

2003-01-01

262

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

Microsoft Academic Search

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,

K. A. Hamilton

1983-01-01

263

Use of Brine Shrimp, Artemia spp., in Larval Crustacean Nutrition: A Review  

Microsoft Academic Search

Because of convenience in production and their suitable biochemical composition, brine shrimp Artemia spp. nauplii have been adopted as a standard diet in the commercial larviculture of several crustacean species. The nutritional value of Artemia, however, is not constant, but varies both geographically and temporally. During the past decade both the causes of Artemia nutritional variability and methods to improve

Patrick Sorgeloos; Peter Coutteau; Philippe Dhert; Greet Merchie; Patrick Lavens

1998-01-01

264

fl-l,3 GLUCAN ACTIVATION OF CRUSTACEAN HEMOCYTES IN VITRO AND IN VIVO  

Microsoft Academic Search

The effects of 13-1 ,3 glucans on the hemocytes of the freshwater crayfish, Astacus astacus, and the shore crab, Carcinus maenas, were studied in vitro and in vivo to determine the role ofthe prophenoloxidase activating system, in the cellular defense reactions of crustaceans. In vitro, phagocytosis of the bacterium, Moraxella sp. was significantly raised by addition of laminarin, a $-l

VALERIE J. SMITH; KENNETH SODERHALL

265

Organochlorinated contaminants in decapod crustaceans from the coasts of Brittany and Normandy (France)  

Microsoft Academic Search

The contamination and distribution of organochlorinated compounds were considered in three crustacean species (edible crab, Cancer pagurus; spider crab, Maja brachydactyla; velvet swimming crab, Necora puber) from five sites along the coasts of Brittany and Normandy (Western and North-Western France). PCBs (16 single congeners), pp?-DDE and HCB were measured in hepatopancreas, gonads and muscle: in all, 175 samples were analysed.

N. Bodin; A. Abarnou; A.-M. Le Guellec; V. Loizeau; X. Philippon

2007-01-01

266

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

2012-06-01

267

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

268

Differential expression profiling of components associated with exoskeletal hardening in crustaceans  

Microsoft Academic Search

BACKGROUND: Exoskeletal hardening in crustaceans can be attributed to mineralization and sclerotization of the organic matrix. Glycoproteins have been implicated in the calcification process of many matrices. Sclerotization, on the other hand, is catalysed by phenoloxidases, which also play a role in melanization and the immunological response in arthropods. Custom cDNA microarrays from Portunus pelagicus were used to identify genes

Anna V Kuballa; Abigail Elizur

2008-01-01

269

Insecticidal juvenile hormone analogs stimulate the production of male offspring in the crustacean Daphnia magna.  

PubMed

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 farnesoate, producing altered sex ratios of offspring. Daphnids were exposed chronically (3 weeks) to sublethal concentrations of methyl farnesoate, the JHA pyriproxyfen, and several nonjuvenoid chemicals to discern whether excess male offspring production is a generic response to stress or a specific response to juvenoid hormones. Only methyl farnesoate and pyriproxyfen increased the percentage of males produced by exposed maternal organisms. As previously reported with methyl farnesoate, acute exposure (24 hr) to either pyriproxyfen or the JHA methoprene caused oocytes maturing in the ovary to develop into males. We performed experiments to determine whether combined effects of a JHA and methyl farnesoate conformed better to a model of concentration addition (indicative of same mechanism of action) or independent joint action (indicative of different mechanisms of action). Combined effects conformed better to the concentration-addition model, although some synergy, of unknown etiology, was evident between the insecticides and the hormone. These experiments demonstrate that insecticidal JHAs mimic the action of the crustacean juvenoid hormone methyl farnesoate, resulting in the inappropriate production of male offspring. The occurrence of such an effect in the environment could have dire consequences on susceptible crustacean populations. PMID:12782492

Olmstead, Allen W; LeBlanc, Gerald A

2003-06-01

270

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

271

Eye Design and Color Signaling in a Stomatopod Crustacean Gonodactylus smithii  

Microsoft Academic Search

Many species of stomatopod crustaceans have multiple spectral classes of photoreceptors in their retinas. Behavioral evidence also indicates that stomatopods are capable of discriminating objects by their spectral differences alone. Most animals use only two to four different types of photoreceptors in their color vision systems, typically with broad sensitivity functions, but the stomatopods apparently include eight or more narrowband

Chuan-Chin Chiao; Thomas W. Cronin; N. Justin Marshall

2000-01-01

272

Production and purification of protease from a Bacillus subtilis that can deproteinize crustacean wastes  

Microsoft Academic Search

A protease-producing microorganism was isolated in northern Taiwan and identified as a strain of Bacillus subtilis. B. subtilis Y-108 thus isolated can be used for deproteinization of crustacean wastes in the preparation of chitin. For deproteinization tests, liquid phase fermentation of untreated shrimp shell, crab shell, and lobster shell wastes with this microbe showed protein removal of 88, 67, and

Jen-Kuo Yang; Ing-Lung Shih; Yew-Min Tzeng; San-Lang Wang

2000-01-01

273

MYSID CRUSTACEANS AS POTENTIAL TEST ORGANISMS FOR THE EVALUATION OF ENVIRONMENTAL ENDOCRINE DISRUPTORS: A REVIEW  

EPA Science Inventory

Verslycke, Tim A., Nancy Fockedey, Charles L. McKenney, Jr., Stephen D. Roast, Malcolm B. Jones, Jan Mees and Colin R. Janssen. 2004. Mysid Crustaceans as Potential Test Organisms for the Evaluation of Environmental Endocrine Disruption: A Review. Environ. Toxicol. Chem. 23(5):12...

274

A structure-function analysis of ion transport in crustacean gills and excretory organs.  

PubMed

Osmotic and ionic regulation in the Crustacea is mostly accomplished by the multifunctional gills, together with the excretory organs. In addition to their role in gas exchange, the gills constitute organs of active, transepithelial, ion transport, an activity of major importance that underlies many essential physiological functions like osmoregulation, calcium homeostasis, ammonium excretion and extracellular pH regulation. This review focuses on structure-function relationships in crustacean gills and excretory effectors, from the organ to molecular levels of organization. We address the diversity of structural architectures encountered in different crustacean gill types, and in constituent cell types, before examining the physiological mechanisms of Na(+), Cl(-), Ca(2+) and NH(4)(+) transport, and of acid-base equivalents, based on findings obtained over the last two decades employing advanced techniques. The antennal and maxillary glands constitute the principal crustacean excretory organs, which have received less attention in functional studies. We examine the diversity present in antennal and maxillary gland architecture, highlighting the structural similarities between both organ types, and we analyze the functions ascribed to each glandular segment. Emphasis is given to volume and osmoregulatory functions, capacity to produce dilute urine in freshwater crustaceans, and the effect of acclimation salinity on urine volume and composition. The microanatomy and diversity of function ascribed to gills and excretory organs are appraised from an evolutionary perspective, and suggestions made as to future avenues of investigation that may elucidate evolutionary and adaptive trends underpinning the invasion and exploitation of novel habitats. PMID:17604200

Freire, Carolina A; Onken, Horst; McNamara, John C

2008-11-01

275

Characterization of ecdysteroid 26-hydroxylase: an enzyme involved in molting hormone inactivation.  

PubMed

Insect molting hormone (ecdysteroid) inactivation occurs by several routes, including 26-hydroxylation and further oxidation to the 26-oic acids. Thus, the ecdysteroid 26-hydroxylase is a critical enzyme involved in precise regulation of ecdysteroid titers during insect development. Administration of the ecdysteroid agonist, RH-5849 (1,2-dibenzoyl, 1-tert-butyl hydrazone), or 20-hydroxyecdysone to the tobacco hornworm, Manduca sexta, results in induction of ecdysteroid 26-hydroxylase activity in midgut mitochondria and microsomes. The biochemical and kinetic properties of the ecdysteroid 26-hydroxylase were investigated. The mitochondrial enzyme was found to have optimal activity at a pH of 7. 5 in a Hepes or sodium phosphate buffer at 30-37 degrees C. The apparent K(m) of the microsomal 26-hydroxylase for 20-hydroxyecdysone substrate was lower than that of the mitochondrial enzyme for either 20-hydroxyecdysone or ecdysone substrate. The V(max) of the 26-hydroxylase in both subcellular fractions was slightly higher using 20-hydroxyecdysone as substrate compared to ecdysone. Demonstration that activity of the mitochondrial 26-hydroxylase was inhibited by incubation in a CO (or N(2)) atmosphere, taken together with the requirement for reducing cofactor and the efficacy of the P450 inhibitors, ketoconazole and fenarimol, provided strong evidence that the hydroxylase is cytochrome P450-dependent. Indirect evidence suggested that the mitochondrial and microsomal ecdysteroid 26-hydroxylase(s) could exist in a less active dephosphorylated state or more active phosphorylated state. Using Escherichia coli alkaline phosphatase to remove covalently bound phosphate groups, the activity of the 26-hydroxylase was decreased and, conversely, activity was enhanced using a cAMP-dependent protein kinase with appropriate cofactors. In addition, the protein kinase was shown to reactivate the 26-hydroxylase activity in alkaline phosphatase-treated fractions. PMID:10775427

Williams, D R; Fisher, M J; Rees, H H

2000-04-15

276

S-adenosylmethionine regulates thiopurine methyltransferase activity and decreases 6-mercaptopurine cytotoxicity in MOLT lymphoblasts.  

PubMed

Six-mercaptopurine (6-MP) is a pro-drug widely used in treatment of various diseases, including acute lymphoblastic leukaemia (ALL). Side-effects of thiopurine therapy have been correlated with thiopurine methyltransferase (TPMT) activity. We propose a novel TPMT-mediated mechanism of S-adenosylmethionine (SAM)-specific effects on 6-mercaptopurine (6-MP) induced cytotoxicity in a model cell line for acute lymphoblastic leukemia (MOLT). Our results show that exogenous SAM (10-50microM) rescues cells from the toxic effects of 6-MP (5microM) by delaying the onset of apoptosis. We prove that the extent of methylthioinosine monophosphate (MeTIMP) induced inhibition of de novo purine synthesis (DNPS) determines the concentrations of intracellular ATP, and consequently SAM, which acts as a positive modulator of TPMT activity. This leads to a greater conversion of 6-MP to inactive 6-methylmercaptopurine, and thus lower availability of thioinosine monophosphate for the biotransformation to cytotoxic thioguanine nucleotides (TGNs) and MeTIMP. We further show that the addition of exogenous SAM to 6-MP treated cells maintains intracellular SAM levels, TPMT activity and protein levels, all of which are diminished in cells incubated with 6-MP. Since TPMT mRNA levels remained unaltered, the effect of SAM appears to be restricted to protein stabilisation rather than an increase of TPMT expression. We thus propose that SAM reverses the extent of 6-MP cytotoxicity, by acting as a TPMT-stabilizing factor. This study provides new insights into the pharmacogenetics of thiopurine drugs. Identification of SAM as critical modulator of TPMT activity and consequently thiopurine toxicity may set novel grounds for the rationalization of thiopurine therapy. PMID:19428339

Milek, Miha; Karas Kuzelicki, Natasa; Smid, Alenka; Mlinaric-Rascan, Irena

2009-06-15

277

Conservation of structure, signaling and pharmacology between two serotonin receptor subtypes from decapod crustaceans, Panulirus interruptus and Procambarus clarkii  

PubMed Central

SUMMARY Serotonin (5-HT) plays important roles in the maintenance and modulation of neural systems throughout the animal kingdom. The actions of 5-HT have been well characterized for several crustacean model circuits; however, a dissection of the serotonergic transduction cascades operating in these models has been hampered by the lack of pharmacological tools for invertebrate receptors. Here we provide pharmacological profiles for two 5-HT receptors from the swamp crayfish, Procambarus clarkii: 5-HT2? and 5-HT1?. In so doing, we also report the first functional expression of a crustacean 5-HT1 receptor, and show that it inhibits accumulation of cAMP. The drugs mCPP and quipazine are 5-HT1? agonists and are ineffective at 5-HT2?. Conversely, methiothepin and cinanserin are antagonists of 5-HT2? but do not block 5-HT1?. A comparison of these two receptors with their orthologs from the California spiny lobster, Panulirus interruptus, indicates conservation of protein structure, signaling and pharmacology. This conservation extends beyond crustacean infraorders. The signature residues that form the ligand-binding pocket in mammalian 5-HT receptors are found in the crustacean receptors. Similarly, the protein domains involved in G protein coupling are conserved between the two crustacean receptors and other characterized arthropod and mammalian 5-HT receptors. Considering the apparent conservation of pharmacological properties between crustacean 5-HT receptors, these tools could be applicable to related crustacean physiological preparations.

Spitzer, Nadja; Edwards, Donald H.; Baro, Deborah J.

2014-01-01

278

Crustaceans from a tropical estuarine sand-mud flat, Pacific, Costa Rica, (1984-1988) revisited.  

PubMed

The availability of data sets for time periods of more than a year is scarce for tropical environments. Advances in hardware and software speed-up the re-analysis of old data sets and facilitates the description of population oscillations. Using recent taxonomic literature and software we have updated and re-analized the information on crustacean diversity and population fluctuations from a set of cores collected at a mud-sand flat in the mid upper Gulf of Nicoya estuary, Pacific coast of Costa Rica (1984-1988). A total of 112 morphological species of macroinvertebrates was found, of which 29 were crustaceans. Taxonomic problems, maily with the peracarids, prevented the identification of a group of species. The abundance patterns of the crab Pinnixa valerii, the ostracod Cyprideis pacifica, and the cumacean Coricuma nicoyensis were analized with the Generalized Additive Models of the free software R. The models evidenced a variety of population oscillations during the sampling period. These oscillations probably included perturbations induced by external factors, like the strong red tide events of 1985. In additon, early on 1984 the populations might have been at an altered state due to the inpact of El Niño 1982-83. Thus, the oscillations observed during the study period departed from the expected seasonality (dry vs rainy) pattern and are thus considered atypical for this tropical estuarine tidal-flat. Crustacean diversity and population peaks were within the range of examples found in worldwide literature. However, abundances of the cumacean C. nicoyensis, an endemic species, are the highest reported for a tropical estuary. Comparative data from tropical tidal flat crustaceans continues to be scarce. Crustaceans (total vs groups) had population changes in response to the deployment of predator exclusion cages during the dry and rainy seasons of 1985. Temporal and spatial patchiness characterized the abundances of P. valeri, C. pacifica and C. nicoyenis. PMID:23342527

Vargas-Zamora, José A; Sibaja-Cordero, Jeffrey A; Vargas-Castillo, Rita

2012-12-01

279

Hatching rhythms and dispersion of decapod crustacean larvae in a brackish coastal lagoon in Argentina  

NASA Astrophysics Data System (ADS)

Mar Chiquita, a brackish coastal lagoon in central Argentina, is inhabited by dense populations of two intertidal grapsid crab species, Cyrtograpsus angulatus and Chasmagnathus granulata. During a preliminary one-year study and a subsequent intensive sampling programme (November December 1992), the physical properties and the occurrence of decapod crustacean larvae in the surface water of the lagoon were investigated. The lagoon is characterized by highly variable physical conditions, with oligohaline waters frequently predominating over extended periods. The adjacent coastal waters show a complex pattern of semidiurnal tides that often do not influence the lagoon, due to the existence of a sandbar across its entrance. Besides frequently occurring larvae (exclusively freshly hatched zoeae and a few megalopae) of the two dominating crab species, those of three other brachyurans ( Plathyxanthus crenulatus, Uca uruguayensis, Pinnixa patagonica) and of one anomuran (the porcellanid Pachycheles haigae) were also found occasionally. Caridean shrimp ( Palaemonetes argentinus) larvae occurred in a moderate number of samples, with a maximum density of 800·m-3. The highest larval abundance was recorded in C. angulatus, with almost 8000°m-3. Significantly more C. angulatus and C. granulata zoeae occurred at night than during daylight conditions, and more larvae (statistically significant only in the former species) during ebb (outflowing) than during flood (inflowing) tides. In consequence, most crab zoeae were observed during nocturnal ebb, the least with diurnal flood tides. Our data suggest that crab larvae do not develop in the lagoon, where the adult populations live, but exhibit an export strategy, probably based upon exogenously coordinated egg hatching rhythms. Zoeal development must take place in coastal marine waters, from where the megalopa eventually returns for settlement and metamorphosis in the lagoon. Significantly higher larval frequency of C. granulata in low salinities (?12‰) and at a particular sampling site may be related to local distribution patterns of the reproducing adult population. Unlike crab larvae, those of shrimp ( P. argentinus) are retained inside the lagoon, where they develop from hatching through metamorphosis. They significantly prefer low salinity and occur at the lagoon surface more often at night. These patterns cannot be explained by larval release rhythms like those in brachyuran crabs, but may reflect diel vertical migrations to the bottom. It is concluded that osmotic stress as well as predation pressure exerted by visually directed predators (small species or life-cycle stages of estuarine fishes) may be the principal selection factors for the evolution of hatching and migration rhythms in decapod larvae, and that these are characteristics of export or retention mechanisms, respectively.

Anger, K.; Spivak, E.; Bas, C.; Ismael, D.; Luppi, T.

1994-12-01

280

The Y-organ secretory activity fluctuates in relation to seasons of molt and reproduction in the brachyuran crab, Metopograpsus messor (Grapsidae): Ultrastructural and immunohistochemical study.  

PubMed

This paper presents a first-time report on the localization, structure and seasonal secretory activity of the Y-organ of a grapsid brachyuran crab (Metopograpsus messor). Having exhibited discrete seasonality with reference to the programming of molt and reproduction, this brachyuran crab has offered us an excellent model to obtain a clear picture of the fluctuating secretory nature of the Yorgan, all the way through the reproductive (August-December) as well as the molt-reproduction active (January-May) and inactive (June-July) seasons. Ultrastructural studies revealed that the secretion of the Y-organ was at its peak in premolt crabs during molt-reproduction season (January-May). Interestingly, the Y-organs of the intermolt females that engaged in breeding activity showed higher levels of secretion than those of the molt-reproduction inactive season (June-July), implicating the gland's involvement in reproduction. Immunohistochemical studies using the antiserum raised against 2-succinyl conjugate of ecdysone have demonstrated the ecdysteroid nature of the secretion from the Y-organ, and results of the quantitative assay of ecdysteroids (through radioimmunoassay) revealed that the hormone titer fluctuates in consonance with the Y-organ's secretory activity during seasons of molt and reproduction. Pertinently, not only that the paper gives us a comprehensive understanding on the secretory activity of the Y-organ in a season-dependent fashion, it also allows us to have a better insight into the gland's function related to molting and reproduction (for the first time) in a grapsid brachyuran crab. PMID:24291010

Shyamal, Sharmishtha; Sudha, K; Gayathri, N; Anilkumar, G

2014-01-15

281

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

282

Changes in abundance and spatial distribution of geese molting near Teshekpuk Lake, Alaska: Interspecific competition or ecological change?  

USGS Publications Warehouse

Goose populations molting in the Teshekpuk Lake Special Area of the National Petroleum Reserve-Alaska have changed in size and distribution over the past 30 years. Black brant (Branta bernicla nigricans) are relatively stable in numbers but are shifting from large, inland lakes to salt marshes. Concurrently, populations of greater white-fronted geese (Anser albifrons frontalis) have increased seven fold. Populations of Canada geese (Branta canadensis and/or B. hutchinsii) are stable with little indication of distributional shifts. The lesser snow goose (Anser caerulescens caerulescens) population is proportionally small, but increasing rapidly. Coastline erosion of the Beaufort Sea has altered tundra habitats by allowing saltwater intrusion, which has resulted in shifts in composition of forage plant species. We propose two alternative hypotheses for the observed shift in black brant distribution. Ecological change may have altered optimal foraging habitats for molting birds, or alternatively, interspecific competition between black brant and greater white-fronted geese may be excluding black brant from preferred habitats. Regardless of the causative mechanism, the observed shifts in species distributions are an important consideration for future resource planning. ?? 2007 Springer-Verlag.

Flint, P. L.; Mallek, E. J.; King, R. J.; Schmutz, J. A.; Bollinger, K. S.; Derksen, D. V.

2008-01-01

283

Effect of forced molting on quantity and quality of semen in turkey breeder males as influenced by diet.  

PubMed

Broad Breasted White turkey males were induced to molt by imposing periods of nonstimulatory light and short periods of water and feed deprival starting at 54 weeks of age. Birds kept under 8 or 10 hours of light per day began to molt within 3 weeks, and most had terminated semen production within 4 weeks. When returned to stimulatory light, the birds began to produce semen within 4 weeks and reached peak production within 10 weeks. However, this level of production was lower than the original level attained as young birds. The recycled males produced approximately 20 percent more semen than the males kept under constant stimulatory light, and the semen from the recycled males contained 1 to 2 billion additional sperm per ml. The percentage of normal sperm decreased with increase in age of birds irrespective of light treatment. A skip-a-day-per-week feeding schedule imposed on all males from 54 to 78 weeks of age had no appreciable effect on body weight or efficiency of feed utilization. Also, imposition of feed and water restrictions had no apparent effect on early termination or recovery of semen production. PMID:1228731

Woodard, A E; Ogasawara, F X; Snyder, R L; Stinnett, V

1975-11-01

284

PCB, PCDD\\/F and PBDE levels and profiles in crustaceans from the coastal waters of Brittany and Normandy (France)  

Microsoft Academic Search

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD\\/Fs) were analysed in the muscle of various edible marine crustaceans (spider crab, edible crab, velvet swimming crab and Norway lobster) from the Brittany and Normandy coasts (France). The highest concentrations were measured in species collected from Antifer (Seine Bay). PCB and PBDE patterns in crustacean muscles were

N. Bodin; A. Abarnou; D. Fraisse; S. Defour; V. Loizeau; A.-M. Le Guellec; X. Philippon

2007-01-01

285

Amino acid sequences of both isoforms of crustacean hyperglycemic hormone (CHH) and corresponding precursor-related peptide in Cancer pagurus  

Microsoft Academic Search

Both isoforms of the crustacean hyperglycemic hormone (CHH) and corresponding crustacean hyperglycemic hormone precursor-related peptide (CPRP) derived from HPLC-purified sinus gland extracts from the edible crab Cancer pagurus were fully characterised by microsequencing and mass spectrometry. The amino acid sequences of the CHH isoforms were almost identical except that the N-terminus of the minor isoform (CHH-I), was glutamine rather than

J. Sook Chung; Mark C. Wilkinson; Simon G. Webster

1998-01-01

286

Evidence for behavioral sensitivity to near-UV light in the deep-sea crustacean Systellaspis debilis  

Microsoft Academic Search

The role of UV light in the deep-sea environment has been discounted in the past, due to the assumptions that (1) there is insufficient UV light available for vision and, therefore (2) deep-sea organisms would not be sensitive to these wavelengths. A recent study that employed electrophysiological techniques on dark-captured deep-sea crustaceans demonstrated that several species of deep-sea crustaceans possess

T. M. Frank; E. A. Widder

1994-01-01

287

Do eel parasites reflect the local crustacean community? A case study from the Rhine River system.  

PubMed

In 2003, the parasite fauna of 197 European eels Anguilla anguilla, captured at three different locations (Laufenburg, Karlsruhe and Beneeden Leeuwen) in the River Rhine, was analysed. The eels harboured a total of 18 species, among them the protozoa (Myxidium giardi, Myxobolus kotlani and Trypanosoma granulosum), acanthocephalans (Acanthocephalus anguillae, Acanthocephalus lucii, Echinorhynchus truttae, Pomphorhynchus laevis), nematodes (Paraquimperia tenerrima, Pseudocapillaria tomentosa, Camallanus lacustris, Raphidascaris acus, Spinitectus inermis and Anguillicola crassus), cestodes (Bothriocephalus claviceps and Proteocephalus macrocephalus) and monogeneans (Pseudodactylogyrus sp.). The parasite fauna at the different locations is discussed with respect to the crustacean fauna present at these locations. The investigation shows that changes in the composition of the crustacean fauna, due to the anthropogenic breakdown of a biogeographic barrier, are reflected in the composition of the intestinal eel parasite fauna. PMID:17578598

Thielen, Frankie; Münderle, Marcel; Taraschewski, Horst; Sures, Bernd

2007-06-01

288

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

PubMed

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. PMID:23846305

Kakui, Keiichi; Hiruta, Chizue

2013-09-01

289

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

290

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

2010-01-01

291

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

292

NEW MARINE DECAPOD CRUSTACEANS FROM WATERS INFLUENCED BY HYDROmERMALDISCHARGE, BRINE, AND HYDROCARBON SEEPAGE  

Microsoft Academic Search

Five species of decapod crustaceans new to science are described. These are caridean shrimps of the family Bresiliidae-Alvinocaris markf!nsis from a Mid-Atlantic Rift Valley hydrothermal field, A. muricola from a cold brine seep at the foot ofthe West Florida Escarpment in the GulfofMexico, and A. stactophila from a hydrocarbon seep on the continental slope of the northern Gulfof Mexico, with

AUSTIN B. WILLIAMS

293

Hatching rhythms and dispersion of decapod crustacean larvae in a brackish coastal lagoon in Argentina  

Microsoft Academic Search

Mar Chiquita, a brackish coastal lagoon in central Argentina, is inhabited by dense populations of two intertidal grapsid\\u000a crab species,Cyrtograpsus angulatus andChasmagnathus granulata. During a preliminary one-year study and a subsequent intensive sampling programme (November–December 1992), the physical\\u000a properties and the occurrence of decapod crustacean larvae in the surface water of the lagoon were investigated. The lagoon\\u000a is characterized by

K. Anger; E. Spivak; C. Bas; D. Ismael; T. Luppi

1994-01-01

294

Adult neurogenesis: Examples from the decapod crustaceans and comparisons with mammals  

PubMed Central

Defining evolutionary origins is a means of understanding an organism’s position within the integrated web of living beings, and to not only to trace characteristics back in time, but also to project forward in an attempt to reveal relationships with more recently evolved forms. Both the vertebrates and arthropods possess condensed nervous systems, but this is dorsal in the vertbrates and ventral in the arthropods. Also, whereas the nervous system in the vertebrates develops from a neural tube in the embryo, that of the arthropods comes from an ectodermal plate. Despite these apparently fundamental differences, it is now generally accepted that life-long neurogenesis, the generation of functionally integrated neurons from progenitor cells, is a common feature of the adult brains of a variety of organisms, ranging from insects and crustaceans to birds and mammals. Among decapod crustaceans, there is evidence for adult neurogenesis in basal species of the Dendrobranchiata, as well as in more recent terrestrial, marine and fresh-water species. The widespread nature of this phenomenon in decapod species may relate to the importance of the adult-born neurons, although their functional contribution is not yet known. The many similarities between the systems generating neurons in the adult brains of decapod crustaceans and mammals, reviewed in this paper, suggest that adult neurogenesis is governed by common ancestral mechanisms that have been retained in a phylogenetically broad group of species.

Sandeman, David C.; Bazin, Francois; Beltz, Barbara S.

2011-01-01

295

Cross communication between signaling pathways: juvenoid hormones modulate ecdysteroid activity in a crustacean.  

PubMed

Methyl farnesoate is a juvenoid hormone that regulates a variety of processes in crustaceans including male sex determination among daphnids (Branchiopoda, Cladocera). The synthetic juvenoids pyriproxyfen and fenoxycarb mimic the action of methyl farnesoate in daphnids. In the present study we tested the hypothesis that juvenoids also can regulate ecdysteroid activity in a crustacean (Daphnia magna). Methyl farnesoate, pyriproxyfen, and fenoxycarb all disrupted ecdysteroid-regulated aspects of embryo development in daphnids. Exposure of ecdysteroid-responsive cells to 20-hydroxyecdysone reduced cell proliferation and increased mRNA levels of the ecdysone receptor and its partner protein ultraspiracle. Co-treatment of cells with the juvenoid pyriproxyfen attenuated all of these ecdysteroid mediated responses. While juvenoids functioned as anti-ecdysteroids in both intact embryos and in cultured cells, 20-hydroxyecdysone showed no evidence of acting as an anti-juvenoid. The combined effects of pyroproxyfen with the ecdysteroid synthesis inhibitor fenarimol and the ecdysteroid receptor antagonist testosterone were evaluated in an effort to discern whether the action of the juvenoids were additive with those of know anti-ecdysteroids. The anti-ecdysteroid effects of pyriproxyfen were non-additive with those of either anti-ecdysteroid. Rather, joint effects conformed to a model of synergy. These results demonstrated that juvenoids elicit anti-ecdysteroidal activity in a crustacean through a unique mechanism of action. A model involving receptor partner deprivation is proposed that explains the synergistic interactions observed. PMID:15449346

Mu, Xueyan; Leblanc, Gerald A

2004-10-01

296

Etoposide-induced apoptosis in lymphoblastoid leukaemic MOLT-4 cells: evidence that chromatin condensation, loss of phosphatidylserine asymmetry and apoptotic body formation can occur independently.  

PubMed

Apoptosis is characterised by a series of typical morphological features, such as nuclear and cellular convolution, chromatin condensation and the final disintegration of the cell into membrane-bound apoptotic bodies, which are phagocytosed, by neighbouring cells. Relocation of phosphatidylserine residues from the inner leaflet of the cellular membrane to being exposed on the cell surface is a necessary event for the phagocytic elimination of apoptotic cell debris. Using the MOLT-4 lymphoblastoid leukaemic cell line we investigated whether the formation of apoptotic bodies and loss of phosphatidylserine asymmetry were causally related. We have previously demonstrated that classical apoptotic morphology, including production of apoptotic bodies, was only possible in etoposide-treated MOLT-4 cells when administered in the presence of non-cytotoxic doses (200 microM) of aurin tricarboxylic acid (ATA). Electron microscopic analysis, followed by the quantitation of the ultrastructural morphological features of apoptotic MOLT-4 cells, demonstrated that the etoposide and ATA co-treatment, which caused the cellular fragmentation into apoptotic bodies, was closely associated with extensive chromatin condensation in individual cells. In this model however, the addition of ATA to frank cytotoxic doses of etoposide (50 microM), which we confirmed lead to formation of apoptotic bodies, caused no further increase in externalisation of phosphatidylserine moieties as determined by staining with fluorescence labelled annexin V. Consequently, in MOLT-4 cells undergoing etoposide-induced apoptosis, the mole-cular mechanisms leading to loss of phosphatidylserine asymmetry and the formation of apoptotic bodies are not causally related. PMID:11773706

Ramirez, C D; Catchpoole, D R

2002-02-01

297

Formation and structure of the ephippium (resting egg case) in relation to molting and egg laying in the water flea Daphnia pulex De Geer (Cladocera: Daphniidae).  

PubMed

Resting eggs produced by daphnid species in response to environmental deterioration play an important role in colonizing new habitats or in re-establishing extinct populations. Females lay resting eggs into the space within the dorsal part of their carapace and form an egg case called the ephippium to protect them. Previous studies mainly reported the morphology of the completely formed ephippium and/or the forming ephippium of an uncertain stage. To understand ephippium formation and to clarify key transitions in the formation of resting eggs, we examined the structure and formation of the ephippium in the water flea Daphnia pulex De Geer (Cladocera: Daphniidae) by stereomicroscopy, histology, and scanning electron microscopy. The females used in this study produced resting eggs by obligate parthenogenesis. We divided ephippium formation into four stages based on two molts and a single ovulation, as follows. Stage I begins 13 min after molting in adult females that do not ovulate. In Stage II, immediately after the first molt, a protuberance appears beneath the neck region and the carapace begins to thicken. In Stage III, the resting eggs ovulate and the carapace in the area of the forming ephippium becomes much thicker than the normal carapace and accumulates dark pigmentation. In Stage IV, following the second molt, the female sheds the ephippium with the enclosed resting eggs and forms a new carapace. These stages will provide a useful reference for future studies on resting egg formation. J. Morphol. 275:760-767, 2014. © 2014 Wiley Periodicals, Inc. PMID:24500908

Hiruta, Chizue; Tochinai, Shin

2014-07-01

298

Comparison of fatty acid, cholesterol, vitamin A and E composition, and trans fats in eggs from brown and white egg strains that were molted or nonmolted.  

PubMed

The impact of egg color, hen strain, and molting on the nutritional composition of eggs is limited. Therefore, this study compared nutritional composition and component percentages of cage-produced shell eggs with respect to egg color, hen strain, and molt. Four strains were selected from the North Carolina Layer Performance and Management Test: Hy-Line Brown (HB) and Bovans Brown (BB), and Hy-Line W-36 (HW) and Bovans White (BovW) were selected. Two groups from each strain were selected and 2 groups of molted HW and BovW were selected and compared with their nonmolted counterparts to examine the molt's impact. Two sets of eggs from each replicate were collected simultaneously at 101 wk of age. One sample of eggs was broken into a 12-egg pool stomached for 3 min (n = 12 samples), then divided into six 50-mL tubes, sealed, and frozen to be sent for cholesterol, n-3 fatty acids, saturated fat, monounsaturated fats, polyunsaturated fats, ?-carotene, vitamin A, and vitamin E analyses. The other set of 12 eggs was then assessed for component percentages. The HW eggs had a greater (P < 0.05) percentage of yolk than the BovW eggs of 28.12 versus 27.00%, respectively; however, the BovW eggs had 1.0% more albumen. The HB and BB egg components were not different. Brown eggs were heavier (P < 0.01) than white eggs. White eggs had greater (P < 0.0001) percent yolk and the brown eggs had greater (P < 0.0001) percent albumen. The eggs from molted hens had a greater (P < 0.001) percent shell. Total fat content in the samples was (P < 0.05) higher in white eggs by 0.70% than brown eggs due to increased saturated and polyunsaturated fats. The molting of hens reduced (P < 0.01) saturated fats by 0.21% in the egg. Vitamin A levels were higher (P < 0.0001) in white eggs, and vitamin E was higher (P < 0.0001) in brown eggs. Strain and molt appear to influence nutrient composition and component percentages in eggs produced from laying hens. PMID:24235237

Anderson, Kenneth E

2013-12-01

299

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

300

[Faunal characteristics and distribution pattern of crustaceans in the vicinity of Pearl River estuary].  

PubMed

Based on the data of bottom trawl surveys in the vicinity of Pearl River estuary in August (summer), October (autumn), December (winter) 2006, and April (spring) 2007, the faunal characteristics and distribution pattern of crustaceans were analyzed. A total of 54 species belonging to 25 genera, 17 families, and 2 orders were collected, including 22 species of shrimps, 22 species of crabs, and 10 species of squills. Most of the crustaceans were tropical-subtropical warm-water species, a few of them were eurythermal species, and no warm-water and cold-water species occurred. Euryhaline species were most abundant, followed by halophile species, and the low-salinity species were the least. Most of the crustacean species belonged to the fauna of Indian Ocean-western Pacific Ocean. The faunal assemblages were closer to those of the East China Sea, Philippine Sea, Indonesia Sea, and the Japan Sea, and estranger with those of the Yellow Sea, Bohai Sea, and Korea Sea. The dominant species were Metapenaeus joyner, Oratosquilla oratoria, Charybdis miles, Portunus sanguinolentus, Harpiosquilla harpax, Charybdis feriatus, Charybdis japonica, Oratosquilla nepa, Solenocera crassicornis, Portunus trituberculatus, and Calappa philargius. The crustaceans had the largest species number (33) in autumn and the least one (26) in spring, and the highest stock density at the water depth of < 40 m, especially at 10-20 m. The average stock density of the crustaceans was estimated to be 99.60 kg x km(-2), with the highest (198.93 kg x km(-2)) in summer and the lowest (42.35 kg x km(-2)) in spring. Of the 3 species groups, crabs had the highest stock density (41.81 kg x km(-2)), followed by shrimps (38.91 kg x km(-2)), and squills (18.88 kg x km(-2)). The stock densities of the 3 species groups showed an obvious seasonal variation. Shrimps had the highest stock density (120.32 kg x km(-2)) in summer and the lowest density (0.67 kg x km(-2)) in spring, while crabs and squills had the highest density (62.01 and 29.49 kg x km(-2), respectively) in winter and the lowest density (24.64 and 6.30 kg x km(-2), respectively) in autumn. PMID:20077716

Huang, Zi-Rong; Sun, Dian-Rong; Chen, Zuo-Zhi; Zhang, Han-Hua; Wang, Xue-Hui; Wang, Yue-Zhong; Fang, Hong-Da; Dong, Yan-Hong

2009-10-01

301

Role of Calcium-Dependent Proteinase in Molt-Induced Claw Muscle Atrophy.  

National Technical Information Service (NTIS)

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 int...

D. L. Mykles D. M. Skinner

1984-01-01

302

De novo assembly and characterization of a maternal and developmental transcriptome for the emerging model crustacean Parhyale hawaiensis  

PubMed Central

Background Arthropods are the most diverse animal phylum, but their genomic resources are relatively few. While the genome of the branchiopod Daphnia pulex is now available, no other large-scale crustacean genomic resources are available for comparison. In particular, genomic resources are lacking for the most tractable laboratory model of crustacean development, the amphipod Parhyale hawaiensis. Insight into shared and divergent characters of crustacean genomes will facilitate interpretation of future developmental, biomedical, and ecological research using crustacean models. Results To generate a transcriptome enriched for maternally provided and zygotically transcribed developmental genes, we created cDNA from ovaries and embryos of P. hawaiensis. Using 454 pyrosequencing, we sequenced over 1.1 billion bases of this cDNA, and assembled them de novo to create, to our knowledge, the second largest crustacean genomic resource to date. We found an unusually high proportion of C2H2 zinc finger-containing transcripts, as has also been reported for the genome of the pea aphid Acyrthosiphon pisum. Consistent with previous reports, we detected trans-spliced transcripts, but found that they did not noticeably impact transcriptome assembly. Our assembly products yielded 19,067 unique BLAST hits against nr (E-value cutoff e-10). These included over 400 predicted transcripts with significant similarity to D. pulex sequences but not to sequences of any other animal. Annotation of several hundred genes revealed P. hawaiensis homologues of genes involved in development, gametogenesis, and a majority of the members of six major conserved metazoan signaling pathways. Conclusions The amphipod P. hawaiensis has higher transcript complexity than known insect transcriptomes, and trans-splicing does not appear to be a major contributor to this complexity. We discuss the importance of a reliable comparative genomic framework within which to consider findings from new crustacean models such as D. pulex and P. hawaiensis, as well as the need for development of further substantial crustacean genomic resources.

2011-01-01

303

Role of gonadal and adrenal steroids and thyroid hormones in the regulation of molting in domestic goose.  

PubMed

Plasma levels of testosterone (T), 17-?-estradiol (E2), progesterone (P4), dehydroepiandrosterone (DHEA), corticosterone (B), thyroxine (T4) and triiodothyronine (T3) were monitored during postnuptial and the prenuptial molt in domestic goose (Anser anser domesticus) in both sexes. 1. At the beginning of postnuptial molt (when the old, worn dawny-, and cover feathers' loss starts) in ganders, the levels of T, E2, P4 decrease while DHEA and B significantly increase. The elevated levels of T4 and low T3 concentrations characteristic of the last phase of the reproduction, remain unchanged. In layers, similar changes were observed, however, B decreases. 2. In the early phase of outgrowth of wing and cover feathers, plasma levels of T, E2 and P4 are low. Elevated B, DHEA and T4 concentrations decrease in ganders, while in layers DHEA increases and B and T4 levels remain unchanged. T3 increases in both sexes. 3. The subsequent intensive outgrowth period of wing- and cover feathers both in ganders and in layers is characterized by very low levels of T, E2, DHEA and T4, but P4 increased, and T3 concentration remain high. 4. At the end of postnuptial molt - when the outgrowth of dawny, cover-, and wing feathers stops - very low T, E2, P4, DHEA and T4 levels and and high T3 plasma levels were found in both sexes. Fast increase of plasma B was detected in ganders, while in geese, B concentration remain high. 5. During prenuptial molting (outgrowth of contour and tail feathers) low E2, P4 and T4, increasing T and DHEA, but very high T3 and B plasma concentration were measured in ganders. In layers, very low T, E2, P4, DHEA and T4 levels, and very high B and T3 levels were found. 6. At the beginning of the fall-winter sexual repose (postmolting stage) T, E2, P4, DHEA and T4 levels increase, T3 and B declines in both sexes. 7. In the subsequent phase of fall-winter period (preparatory stage) there is a further increase in T, P4 and T4, a fast increase of B and a decrease of E2, DHEA and T3 in ganders. In layers, T, P4 and DHEA decrease, B increases and the T4 and T3 do not change. 8. At the beginning of reproduction high T level, unchanged DHEA, slightly declined P4, and decreased E2, T4, T3 and a strong decline of B concentrations occur in ganders. In layers, T is further increased, E2 and P4 shows high levels, and, at the same time DHEA and T3 remain unchanged, while B and T4 decrease. PMID:21388915

Péczely, P; Bogenfürst, F; Kulcsár, Margit; Polgár, Bea

2011-03-01

304

Ovarian steroid production in vitro during gonadal regression in the turkey. II. Changes induced by forced molting.  

PubMed

In the turkey, the onset of incubation behavior is associated with altered ovarian steroidogenesis, ovarian regression, decreased, LH secretion, and increased serum prolactin (Prl) levels. To clarify the relative contribution of circulating LH and Prl to the initiation of ovarian regression, laying hens were exposed for 0, 3, 7, or 14 days to a forced molting procedure (exposure to reduced day length of 6L:18D and removal of feed and water for the initial 3 days) that induces ovarian regression and decreased LH levels but does not increase Prl levels. On each of these days, hens were killed and granulosa and theca interna cells from the largest (F1) and fifth largest (F5) preovulatory follicles and total cells from the small white follicles (SWF) were incubated for 5 h in the presence or absence of ovine LH (oLH; 0-1,000 ng/ml). Force-molted hens exhibited diminished levels of circulating LH, Prl, progesterone (P), androgen (A), and estradiol (E) by Day 3 of treatment. Ovarian atresia began in F1 by the third day of treatment, and included F1 and F5 by the seventh day. No preovulatory follicles were present on the fourteenth day. With both F1 and F5 granulosa cells, production of P in the presence of oLH was initially enhanced (Day 3) and later absent (Day 7). In contrast, production of A by F5 theca interna cells in the presence of oLH was initially suppressed (Day 3) and then returned to pretreatment levels (Day 7).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1751633

Porter, T E; Silsby, J L; Hargis, B M; Fehrer, S C; el Halawani, M E

1991-10-01

305

Transcriptome Analysis of Integument Differentially Expressed Genes in the Pigment Mutant (quail) during Molting of Silkworm, Bombyx mori.  

PubMed

In the silkworm Bombyx mori, pigment mutants with diverse body colors have been maintained throughout domestication for about 5000 years. The silkworm larval body color is formed through the mutual interaction of melanin, ommochromes, pteridines and uric acid. These pigments/compounds are synthesized by the cooperative action of various genes and enzymes. Previous reports showed that melanin, ommochrome and pteridine are increased in silkworm quail (q) mutants. To understand the pigment increase and alterations in pigment synthesis in q mutant, transcriptome profiles of the silkworm integument were investigated at 16 h after head capsule slippage in the fourth molt in q mutants and wild-type (Dazao). Compared to the wild-type, 1161 genes were differentially expressed in the q mutant. Of these modulated genes, 62.4% (725 genes) were upregulated and 37.6% (436 genes) were downregulated in the q mutant. The molecular function of differently expressed genes was analyzed by Blast2GO. The results showed that upregulated genes were mainly involved in protein binding, small molecule binding, transferase activity, nucleic acid binding, specific DNA-binding transcription factor activity and chromatin binding, while exclusively down-expressed genes functioned in oxidoreductase activity, cofactor binding, tetrapyrrole binding, peroxidase activity and pigment binding. We focused on genes related to melanin, pteridine and ommochrome biosynthesis; transport of uric acid; and juvenile hormone metabolism because of their importance in integument coloration during molting. This study identified differently expressed genes implicated in silkworm integument formation and pigmentation using silkworm q mutant. The results estimated the number and types of genes that drive new integument formation. PMID:24718369

Nie, Hongyi; Liu, Chun; Cheng, Tingcai; Li, Qiongyan; Wu, Yuqian; Zhou, Mengting; Zhang, Yinxia; Xia, Qingyou

2014-01-01

306

Temporal and spatial habitat preferences and biotic interactions between mosquito larvae and antagonistic crustaceans in the field.  

PubMed

Investigations on natural antagonists of mosquito larvae found that micro-crustaceans (e.g., Cladocera) control mosquito populations under experimental conditions. However, their relevance for mosquito control under field situations remains widely unclear because important information about habitat preferences and time of occurrence of crustaceans and mosquito larvae are still missing. In order to fill this knowledge gap, a field study was undertaken in different wetland areas of Saxony, Germany, in different habitats (i.e., grassland, forest, and reed-covered wetlands). We found negative interactions between larvae of Ae. vexans and predatory Cyclopoida (Crustacean: Copepoda), which both were dominant during the first two weeks of hydroperiod, at ponds located at grassland habitats. Larvae of Cx. pipiens were spatially associated with competing Cladocera, but they colonized ponds more rapidly. Populations of Cladocera established from the third week of hydroperiod and prevented Cx. pipiens colonization thereafter. Ostracoda were highly abundant during the whole hydroperiod, but their presence was restricted to habitats of reed-covered wetland at one geographical area. Mosquito larvae hardly occurred at those ponds. In general, we found that ponds at the reed-covered wetlands provided better conditions for the initial development of crustaceans and hence, mosquito larval colonization was strongly inhibited. Grassland habitat, in contrast, favored early development of mosquito larvae. This study showed that micro-crustaceans are relevant for mosquito management but their impact on mosquito larvae varies between species and depends on environmental conditions. PMID:24820562

Kroeger, Iris; Liess, Matthias; Duquesne, Sabine

2014-06-01

307

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

2011-07-01

308

Circadian rhythms are not involved in the regulation of circannual reproductive cycles in a sub-tropical bird, the spotted munia.  

PubMed

Circannual rhythms regulate seasonal reproduction in many vertebrates. The present study investigated whether circannual reproductive phenotypes (rhythms in growth of gonads and molt) were generated independently of the circadian clocks in the subtropical non-photoperiodic spotted munia (Lonchura punctulata). Birds were subjected to light:dark (LD) cycles with identical light but varying dark hours, such that the period of LD cycle (T) equaled 16 h (T16; 12 h L:4 h D), 21 h (T21; 12 h L:9 h D), 24 h (T24; 12 h L:12 h D) and 27 h (T27; 12 h L:15 h D), or to continuous light (LL, 24 h L:0 h D) at ~18°C. During the ~21 month exposure, munia underwent at least two cycles of gonadal development and molt; changes in body mass were not rhythmic. This was similar to the occurrence of annual cycles in reproduction and molt observed in wild birds. A greater asynchrony between circannual cycles of gonad development and molt indicated their independent regulation. Females showed reproductive rhythms with similar circannual periods, whilst in males, circannual periods measured between peak gonadal size were longer in T21 and T24 than in T16 or T27. This suggested a sex-dependent timing of annual reproduction in the spotted munia. Also, food availability periods may not influence the circannual timing of reproduction, as shown by the results on the rhythm in gonadal growth and regression in munia under T-photocycles and LL that provided differential light (feeding) hours. Further, a short-term experiment revealed that activity-rest patterns in munia were synchronized with T-photocycles, but were arrhythmic under LL. We conclude that circadian rhythms are not involved in the timing of the annual reproductive cycle in the spotted munia. PMID:24803462

Budki, Puja; Malik, Shalie; Rani, Sangeeta; Kumar, Vinod

2014-07-15

309

Disease will limit future food supply from the global crustacean fishery and aquaculture sectors.  

PubMed

Seafood is a highly traded food commodity. Farmed and captured crustaceans contribute a significant proportion with annual production exceeding 10 M metric tonnes with first sale value of $40bn. The sector is dominated by farmed tropical marine shrimp, the fastest growing sector of the global aquaculture industry. It is significant in supporting rural livelihoods and alleviating poverty in producing nations within Asia and Latin America while forming an increasing contribution to aquatic food supply in more developed countries. Nations with marine borders often also support important marine fisheries for crustaceans that are regionally traded as live animals and commodity products. A general separation of net producing and net consuming nations for crustacean seafood has created a truly globalised food industry. Projections for increasing global demand for seafood in the face of level or declining fisheries requires continued expansion and intensification of aquaculture while ensuring best utilisation of captured stocks. Furthermore, continued pressure from consuming nations to ensure safe products for human consumption are being augmented by additional legislative requirements for animals (and their products) to be of low disease status. As a consequence, increasing emphasis is being placed on enforcement of regulations and better governance of the sector; currently this is a challenge in light of a fragmented industry and less stringent regulations associated with animal disease within producer nations. Current estimates predict that up to 40% of tropical shrimp production (>$3bn) is lost annually, mainly due to viral pathogens for which standard preventative measures (e.g. such as vaccination) are not feasible. In light of this problem, new approaches are urgently required to enhance yield by improving broodstock and larval sourcing, promoting best management practices by farmer outreach and supporting cutting-edge research that aims to harness the natural abilities of invertebrates to mitigate assault from pathogens (e.g. the use of RNA interference therapeutics). In terms of fisheries losses associated with disease, key issues are centred on mortality and quality degradation in the post-capture phase, largely due to poor grading and handling by fishers and the industry chain. Occurrence of disease in wild crustaceans is also widely reported, with some indications that climatic changes may be increasing susceptibility to important pathogens (e.g. the parasite Hematodinium). However, despite improvements in field and laboratory diagnostics, defining population-level effects of disease in these fisheries remains elusive. Coordination of disease specialists with fisheries scientists will be required to understand current and future impacts of existing and emergent diseases on wild stocks. Overall, the increasing demand for crustacean seafood in light of these issues signals a clear warning for the future sustainability of this global industry. The linking together of global experts in the culture, capture and trading of crustaceans with pathologists, epidemiologists, ecologists, therapeutics specialists and policy makers in the field of food security will allow these issues to be better identified and addressed. PMID:22434002

Stentiford, G D; Neil, D M; Peeler, E J; Shields, J D; Small, H J; Flegel, T W; Vlak, J M; Jones, B; Morado, F; Moss, S; Lotz, J; Bartholomay, L; Behringer, D C; Hauton, C; Lightner, D V

2012-06-01

310

Thermochemical cycles  

NASA Technical Reports Server (NTRS)

The thermochemical production of hydrogen is described along with the HYDRGN computer program which attempts to rate the various thermochemical cycles. Specific thermochemical cycles discussed include: iron sulfur cycle; iron chloride cycle; and hybrid sulfuric acid cycle.

Funk, J. E.; Soliman, M. A.; Carty, R. H.; Conger, W. L.; Cox, K. E.; Lawson, D.

1975-01-01

311

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

312

High-definition De Novo Sequencing of Crustacean Hyperglycemic Hormone (CHH)-family Neuropeptides*  

PubMed Central

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.

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

2012-01-01

313

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

2012-12-01

314

Evolution and functional divergence of enzymes involved in sesquiterpenoid hormone biosynthesis in crustaceans and insects.  

PubMed

Juvenile hormone (JH) and methyl farnesoate (MF) play well-known roles in the development and reproduction of insects and crustaceans. Juvenile hormone acid O-methyltransferase (JHAMT) and farnesoic acid O-methyltransferase (FAMeT) are the enzymes responsible for catalyzing the biosynthesis of JH and MF, respectively. It is not clear whether the genes that encode these enzymes are present in animal lineages outside of the arthropods. Based on DNA sequence similarity, the literature suggests that an FAMeT ortholog is present in humans. However, vertebrates do not appear to produce JH or MF. To help unravel the evolution of hormonal systems in animals we have carried out the first comparative genomic analysis of JHAMT and FAMeT. We identify the first JHAMT ortholog in a crustacean genome, and FAMeT orthologs in annelid and cephalochordate genomes. Moreover, phylogenetic analyses suggest that there is no true homolog of FAMeT in humans contrary to previous hypotheses. Our analyses suggest that the presence of multiple FAMeT isoforms in arthropods may be a consequence of different evolutionary mechanisms. The genes responsible for hormone biosynthesis in extant insects and crustaceans appear to have been present at least in the Pancrustacea. Different selective forces appear to have subsequently acted on the two lineages, leading to the present functional divergence. Our use of comparative genomics and phylogenetic analysis advance knowledge of the relationships of the hormonal enzyme genes in question, and provide new insights into the evolution of hormonal systems in the largest animal phylum, the Arthropoda. PMID:19836428

Hui, Jerome H L; Hayward, Alexander; Bendena, William G; Takahashi, Tokiharu; Tobe, Stephen S

2010-03-01

315

Generation of calcium action potentials in crustacean muscle fibers following exposure to sulfhydryl reagents.  

PubMed

The ventroabdominal flexor muscles of the crustacean Atya lanipes, which are normally completely inexcitable, generate trains of overshooting calcium action potentials after exposure to the sulfhydryl reagents known as alpha, beta-unsaturated carbonyl compounds. The chemically induced action potentials are abolished by protein reagents specific for guanidino and amino groups. Attempts to induce excitability by the use of agents that block potassium conductance were without success. It is proposed that calcium channels are made functional by the covalent modification of a calcium protochannel, via the interaction between the introduced carbonyl group and existing arginine residues. PMID:2866914

Zuazaga, C; del Castillo, J

1985-01-01

316

Variations in plasma corticosterone, estrone, estradiol-17 beta, and progesterone concentrations with forced renesting, molt, and body weight of captive female American kestrels.  

PubMed

Corticosterone, progesterone, estradiol-17 beta, and estrone were quantified in plasma collected weekly (April-September) from renesting and nonlaying female American kestrels (Falco sparverius) paired with males in captivity. Hormone levels and body weights for laying females were maximal during courtship and egg-laying periods, while those for non-layers showed no such distinct peaks. This demonstrated that these profiles were not controlled solely by photoperiod. Plasma corticosterone levels were elevated in all females during August and September when kestrels are preparing for migration. For laying females, body weight was positively correlated with plasma estrogen levels. A low spring body weight gain, and not stress, may have prevented the females from breeding in captivity. The photoperiodic control of molt did not appear to be mediated directly by the hormones studied, since there were no changes in hormone levels associated with the onset of molt. PMID:3770430

Rehder, N B; Bird, D M; Laguë, P C

1986-06-01

317

Molecular characterization of an ecdysone inducible gene E75 of Chinese shrimp Fenneropenaeus chinensis and elucidation of its role in molting by RNA interference  

Microsoft Academic Search

Ecdysone inducible gene, E75 is a primary target of ecdysone receptor (EcR), and is found to play a critical role in the molting process of arthropods. In this study, a cDNA encoding the E75 of Chinese shrimp Fenneropenaeus chinensis (FcE75) was cloned using RT-PCR and RACE techniques. FcE75 cDNA was 3611bp in length with an ORF of 2394bp. The deduced

T. A. Jose Priya; Fuhua Li; Jiquan Zhang; Changjian Yang; Jianhai Xiang

2010-01-01

318

RNA interference targeting cathepsin L and Z-like cysteine proteases of Onchocerca volvulus confirmed their essential function during L3 molting  

Microsoft Academic Search

We describe the successful use of RNA interference (RNAi) to investigate gene function in the human filarial parasite Onchocerca volvulus third-stage larvae (L3). We targeted two specific gene products, the O. volvulus cathepsin L (Ov-CPL) and cathepsin Z-like (Ov-CPZ) cysteine proteases, which were proposed to function during O. volvulus L3 molting. We show that fluorescent-labeled Cy™3-dsRNA corresponding to cpl or

Sara Lustigman; Jun Zhang; Jing Liu; Yelena Oksov; Sarwar Hashmi

2004-01-01

319

Evidence for widespread Wolbachia infection in isopod crustaceans: molecular identification and host feminization.  

PubMed Central

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.

Bouchon, D; Rigaud, T; Juchault, P

1998-01-01

320

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

2008-03-01

321

Mass spectrometric elucidation of the neuropeptidome of a crustacean neuroendocrine organ  

PubMed Central

The blue crab Callinectes sapidus has been used as an experimental model organism for the study of regulation of cardiac activity and other physiological processes. Moreover, it is an economically and ecologically important crustacean species. However, there was no previous report on the characterization of its neuropeptidome. To fill in this gap, we employed multiple sample preparation methods including direct tissue profiling, crude tissue extraction and tissue extract fractionation by HPLC to obtain a complete description of the neuropeptidome of C. sapidus. Matrix-assisted laser desorption/ionization (MALDI)-Fourier transform mass spectrometry (FTMS) and MALDI-time-of-flight (TOF)/TOF were utilized initially to obtain a quick snapshot of the neuropeptide profile, and subsequently nanoflow liquid chromatography (nanoLC) coupled with electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) tandem MS analysis of neuropeptide extracts was conducted for de novo sequencing. Simultaneously, the pericardial organ (PO) tissue extract was labeled by a novel N, N-dimethylated leucine (DiLeu) reagent, offering enhanced fragmentation efficiency of peptides. In total, 130 peptide sequences belonging to 11 known neuropeptide families including orcomyotropin, pyrokinin, allatostatin A (AST-A), allatostatin B (AST-B), FMRFamide-like peptides (FLPs), and orcokinin were identified. Among these 130 sequences, 44 are novel peptides and 86 are previously identified. Overall, our results lay the groundwork for future physiological studies of neuropeptides in C. sapidus and other crustaceans.

Hui, Limei; Xiang, Feng; Zhang, Yuzhuo; Li, Lingjun

2012-01-01

322

Morphological changes in Daphnia galeata induced by a crustacean terpenoid hormone and its analog.  

PubMed

Terpenoid hormones in insects (i.e., juvenile hormones) have various effects on physiology, morphology, and behavior, producing a wide range of phenotypic variation. Recent studies have shown that sex determination in cladoceran crustaceans is under the strong control of a major terpenoid hormone of crustaceans, methyl farnesoatote (MF). It can be easily conceived that MF is also a major determinant of other traits in cladocerans. In the present study, morphological changes known as antipredatory responses in a cladoceran Daphnia galeata in response to exposure to MF and a juvenile hormone-mimicking pesticide, fenoxycarb, were investigated. Morphological change was studied using neonates less than 24?h old, exposed either to MF at the concentrations from 1.9 to 30?µg/L, or fenoxycarb at the concentrations from 13 to 200?ng/L, for 6 d. Animals developed a longer helmet at 1.9?µg/L of MF and 25?ng/L of fenoxycarb, and showed a concentration-dependent elongation. However, the tail spine was reduced in size in a concentration-dependent manner. Results of the present study not only give new insight into the mechanisms of inducible defenses in cladocerans, but also provide invaluable information to understand ecological and evolutionary consequences of endocrine disruption through the shift in biological interaction between predator and prey. PMID:20928915

Oda, Shigeto; Kato, Yasuhiko; Watanabe, Hajime; Tatarazako, Norihisa; Iguchi, Taisen

2011-01-01

323

Is crustacean hyperglycaemic hormone precursor-related peptide a circulating neurohormone in crabs?  

PubMed

Sites of synthesis and release patterns of crustacean hyperglycaemic hormone precursor-related peptide (CPRP) were investigated with those of crustacean hyperglycaemic hormone (cHH), in order to determine whether this precursor-related peptide satisfies certain criteria necessary for its definition as a secretable, circulating hormone. Using the edible crab, Cancer pagurus, sites of CPRP synthesis were determined by immunohistochemistry and release patterns of both peptides were determined in vivo and in vitro by radioimmunoassay of haemolymph and eyestalk superfusates. Both peptides were co-released from sinus glands (SGs) following potassium-evoked depolarization of isolated eyestalk preparations. However, stress-evoked in vivo release resulted in apparent non-stoichiometric circulating peptide profiles. This phenomenon is explained by notable differences in clearance rates of the peptides in haemolymph. In contrast to cHH, CPRP is very slowly degraded in vivo. Although CPRP is clearly a circulating peptide, whose release is concomitant with that of cHH, physiologically pertinent roles for this molecule remain to be discovered. PMID:11810320

Wilcockson, David C; Chung, Sook J; Webster, Simon G

2002-01-01

324

Tubular localization of silent calcium channels in crustacean skeletal muscle fibers.  

PubMed

Ca2+-induced Ca2+ release (CICR) in the superficial abdominal flexor muscle of the crustacean Atya lanipes appears to be mediated by a local control mechanism similar to that of vertebrate cardiac muscle, but with an unusually high gain. Thus, Ca2+ influx increases sufficiently the local concentration of Ca2+ in the immediate vicinity of the sarcoplasmic reticulum Ca2+ release channels to trigger the highly amplified release of Ca2+ required for contraction, but is too low to generate a macroscopic inward current (i.e., the Ca2+ channels are silent). To determine the localization of the silent Ca2+ Channels, the mechanical, electrophysiological and ultrastructural properties of the muscle were examined before and after formamide treatment, a procedure that produces the disruption of transverse tubules of striated muscle. We found that tubular disruption decreased tension generation by about 90%; reduced inward current (measured as Vmax, the maximum rate of rise of Sr2+ action potentials) by about 80%; and decreased membrane capacitance by about 77%. The results suggest that ca. 80% of the silent Ca2+ channels are located in the tubular system. Thus, these studies provide further evidence to support the local control mechanism of CICR in crustacean skeletal muscle. PMID:12416723

Monterrubio, J; Ortiz, G; Orkand, P M; Zuazaga, C

2002-01-01

325

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

326

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

327

Influence of molting and starvation on digestive enzyme activities and energy storage in Gammarus fossarum.  

PubMed

Among the many biological responses studied in ecotoxicology, energy-based biomarkers such as digestive enzyme activities and energy reserves appear to be useful predictive tools for detecting physiological disturbances in organisms. However, the use of these biological responses as biomarkers could be limited by the effects of confounding factors (biotic and abiotic) and physiological processes, such as the reproductive cycle. Thus, the optimal use of these biomarkers will be facilitated by understanding the effects of these factors on the energy metabolism of the sentinel species being studied. We considered abiotic factors (temperature and conductivity) in a previous study, whereas the present study investigated the effects of gender, the female reproductive stage, and food availability on the digestive enzyme activities and energy storage of Gammarus fossarum. The results indicated that, during the female reproductive cycle, the activities of digestive enzymes (amylase, cellulase, and trypsin) decreased significantly, whereas the levels of reserves (proteins, lipids, and sugar) increased until the last premolt stage. Restricted food diets only led to decreased amylase activities in both sexes. Food starvation also induced a decrease in the energy outcomes in females, whereas there were no effects in males. In general, the biochemical (digestive enzyme activities) and physiological (energy reserves) responses were more stable in males than in females. These results support the use of males fed ad libitum to limit the effects of confounding factors when using these energy biomarkers in Gammarus fossarum during biomonitoring programs. PMID:24788197

Charron, Laetitia; Geffard, Olivier; Chaumot, Arnaud; Coulaud, Romain; Jaffal, Ali; Gaillet, Véronique; Dedourge-Geffard, Odile; Geffard, Alain

2014-01-01

328

Influence of Molting and Starvation on Digestive Enzyme Activities and Energy Storage in Gammarus fossarum  

PubMed Central

Among the many biological responses studied in ecotoxicology, energy-based biomarkers such as digestive enzyme activities and energy reserves appear to be useful predictive tools for detecting physiological disturbances in organisms. However, the use of these biological responses as biomarkers could be limited by the effects of confounding factors (biotic and abiotic) and physiological processes, such as the reproductive cycle. Thus, the optimal use of these biomarkers will be facilitated by understanding the effects of these factors on the energy metabolism of the sentinel species being studied. We considered abiotic factors (temperature and conductivity) in a previous study, whereas the present study investigated the effects of gender, the female reproductive stage, and food availability on the digestive enzyme activities and energy storage of Gammarus fossarum. The results indicated that, during the female reproductive cycle, the activities of digestive enzymes (amylase, cellulase, and trypsin) decreased significantly, whereas the levels of reserves (proteins, lipids, and sugar) increased until the last premolt stage. Restricted food diets only led to decreased amylase activities in both sexes. Food starvation also induced a decrease in the energy outcomes in females, whereas there were no effects in males. In general, the biochemical (digestive enzyme activities) and physiological (energy reserves) responses were more stable in males than in females. These results support the use of males fed ad libitum to limit the effects of confounding factors when using these energy biomarkers in Gammarus fossarum during biomonitoring programs.

Charron, Laetitia; Geffard, Olivier; Chaumot, Arnaud; Coulaud, Romain; Jaffal, Ali; Gaillet, Veronique; Dedourge-Geffard, Odile; Geffard, Alain

2014-01-01

329

crustaceans drawer  

NSDL National Science Digital Library

Holothurians are animals, related to other echinoderms by their 5-way pseudosymmetry and body composed of calcitic plates. They are not widely known to most people, and when they are, they are called "sea cucumbers."

2001-03-21

330

Multiple adaptive mechanisms affect asparagine synthetase substrate availability in asparaginase-resistant MOLT-4 human leukaemia cells.  

PubMed Central

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.

Aslanian, A M; Kilberg, M S

2001-01-01

331

Long-term changes of the crustacean zooplankton community in Lake Mjøsa, the largest lake in Norway  

Microsoft Academic Search

Lake Mjøsa has been subject to an accelerating eutrophication from the 1950s to the mid 1970s, but comprehensive nutrient re- duction efforts caused marked reductions of phytoplankton production and biomass during the 1980s, a process that continued dur- ing the 1990s. Zooplankton biomass and species composition was considerably affected during the eutrophication and subsequent oligotrophication. Total crustacean zooplankton biomass decreased

Jarl Eivind LØVIK; Gösta KJELLBERG

2003-01-01

332

PCB, PCDD/F and PBDE levels and profiles in crustaceans from the coastal waters of Brittany and Normandy (France).  

PubMed

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analysed in the muscle of various edible marine crustaceans (spider crab, edible crab, velvet swimming crab and Norway lobster) from the Brittany and Normandy coasts (France). The highest concentrations were measured in species collected from Antifer (Seine Bay). PCB and PBDE patterns in crustacean muscles were similar and independent of the geographical area with the predominance of the high chlorinated PCBs (CB153, 138, 118 and 180), and of a few PBDE congeners (BDE47, BDE99, BDE100 and BDE28). Oppositely, dioxin contamination differed with site. The major component in crustaceans from the Seine Bay was 2378-TCDF, whereas specimens from cleaner areas had higher relative concentrations of OCDD. Finally, the comparison of the spider crab contaminant profiles to those measured in mussel and sea bass highlighted two different trends: decapod crustaceans possess relatively strong capacity to metabolise PCBs and PBDEs; however these species might be used as bioindicators for dioxin pollution monitoring in the marine coastal environment. PMID:17434539

Bodin, N; Abarnou, A; Fraisse, D; Defour, S; Loizeau, V; Le Guellec, A-M; Philippon, X

2007-06-01

333

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

334

The organization of the main component DNA of a crustacean genome with a paucity of middle repetitive sequences  

Microsoft Academic Search

The frequency classes and organization of the main component (mc) DNA of a crustacean, the land crab, Gecarcinus lateralis, have been characterized. The reassociation kinetics of 380 nucleotide long mcDNA fragments show that approximately 50% contain sequences repeated more than 800 times. Present in few, if any, copies are sequences repeated from 2 to 800 times. The remainder of the

Christie A. Holland; Dorothy M. Skinner

1977-01-01

335

Uptake of organic material by aquatic invertebrates. VI. Role of epiflora in apparent uptake of glycine by marine crustaceans  

Microsoft Academic Search

Soft-bodied marine invertebrates from most invertebrate phyla are capable of taking up amino acids from seawater. Marine crustaceans were originally reported not to accumulate amino acids. Artemia salina, Limnoria tripunctata, Tigriopus californicus, and Corophium acherusicum were examined for their ability to accumulate C14-labelled glycine from dilute solution in seawater. In initial experiments with Artemia and Limnoria the organisms were found

J. W. Anderson; G. C. Stephens

1969-01-01

336

Characterization of an ovary-specific glutathione peroxidase from the shrimp Metapenaeus ensis and its role in crustacean reproduction  

Microsoft Academic Search

In vertebrates, both reactive oxygen species (ROS) and the corresponding scavenging system components especially glutathione peroxidase (GPx) are indispensible for normal development of the gonads. To investigate the function of GPx in crustaceans, we cloned and characterized a full length GPx (MeGPx) transcript in the penaeid shrimp Metapenaeus ensis. Phylogenetic analysis showed that MeGPx clustered withthe GPx from mollusks and

Long Tao Wu; Ka Hou Chu

2010-01-01

337

Arsenic speciation and spatial and interspecies differences of metal concentrations in mollusks and crustaceans from a South China estuary.  

PubMed

Arsenic speciation and concentrations were determined in mollusks and crustaceans in the intertidal zone from twelve locations in Zhanjiang estuary, South China. Metal concentrations (Ag, As, Cd, Cu, Hg, Ni, Pb, and Zn) were also concurrently determined in these species. Arsenic speciation analysis showed that the less-toxic arsenobetaine (AsB) constituted 80.6-98.8 % of all As compounds, and dimethylarsinic acid (DMA) constituted 0.47-3.44 %. Monomethylarsonic acid (MMA) and As(V) were only detected in the whelk Drupa fiscella and the crab Heteropilumnus ciliatus, respectively. Arsenite [As(III)] was not detected in any of the sampled specimens, but there were also unidentified other As species. A strong spatial variation of metals in the oyster Saccostrea cucullata was found in the estuary, confirming that oysters can be used as a good biomonitor of metal contamination in the studied area. The concentrations of eight metals in the studied mollusks and crustaceans clearly revealed that these invertebrates accumulated different metals to different degrees. Furthermore, As, Cd, Cu, Hg, and Pb contents in mollusks and crustacean samples were below the Food and Agricultural Organization (FAO) safe concentrations, thus there was no obvious health risk from the intake of the metals through marine mollusks and crustaceans consumption. PMID:23475307

Zhang, Wei; Wang, Wen-Xiong; Zhang, Li

2013-05-01

338

SPATIO-TEMPORAL FLUCTUATIONS IN THE DISTRIBUTION AND ABUNDANCE OF DEMERSAL FISH AND EPIBENTHIC CRUSTACEANS IN YAQUINA BAY, OREGON  

EPA Science Inventory

A total of over 32,000 demersal fish and epibenthic crustaceans belonging to 62 species were caught in 42 biweekly trawls from 10 stations in Yaquina Bay, Oregon, during 1967 and 1968. English sole, Parophrys vetulus, was the most abundant species. eventeen species (13 fishes and...

339

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

340

Serotonin-immunoreactive neurons in scorpion pectine neuropils: similarities to insect and crustacean primary olfactory centres?  

PubMed

The pectines of scorpions are a single pair of mechano- and chemosensory appendages located ventrally behind the most posterior pair of walking legs. They are used for probing the substrate in behaviours such as prey tracking and courtship. The sensory afferents on the pectines supply large segmental neuropils with a conspicuous glomerular structure. The pectine neuropils thus bear similarities to insect and crustacean deutocerebral chemosensory centres associated with the antennae, but they also possess idiosyncratic features. One characteristic property of many insect and decapod crustacean olfactory neuropils is their innervation by single, or very few, large serotonergic (inter-) neurons. This feature, among others, has been proposed to support homology of the olfactory lobes in the two arthropod groups. A possible serotonergic innervation of the scorpion pectine neuropils has not yet been studied, despite its apparent diagnostic and functional importance. We thus examined serotonin-immunoreactivity in the pectine neuropils of Androctonus australis and Pandinus imperator. Both scorpion species yielded similar results. The periphery of the neuropil and the matrix between the glomeruli are supplied by a dense network of serotonin-immunoreactive (5-HT-ir) arborisations and varicosities, while the glomeruli themselves are mostly free of 5-HT-ir fibres. The 5-HT-ir supply of the pectine neuropils has two origins. The first is a pair of neurons on each body side, up to 30 ?m in diameter and thus slightly larger than the surrounding somata. These cell bodies are and associated with the neuromeres of the genital and pectine segments. The situation is reminiscent of the 5-HT supply of insect and crustacean olfactory and antennal neuropils. The second 5-HT innervation of the pectine neuropils is from a group of some 10-20 ipsilateral neuronal somata of slightly smaller size (15-20 ?m). These are part of a much larger 5-HT-ir group comprising 70-90 somata. The whole group is located more anteriorly than the single soma mentioned above, and associated with the neuromere of the last (4th) walking leg. When compared to data from other arthropods, our findings may suggest that glomerular organisation is an ancestral feature of primary chemosensory centres innervated by arthropod appendages. This idea needs further scrutiny, although supporting evidence may have been overlooked previously, due to the small size of chemosensory neuropils in walking legs and in reduced segmental appendages. PMID:22445574

Wolf, Harald; Harzsch, Steffen

2012-06-01

341

LTR-Retrotransposons in R. exoculata and Other Crustaceans: The Outstanding Success of GalEa-Like Copia Elements  

PubMed Central

Transposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. They can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. LTR-retrotransposons have been reported in many diverse eukaryote species, describing a ubiquitous distribution. Given their abundance, diversity and their extended ranges in C-values, environment and life styles, crustaceans are a great taxon to investigate the genomic component of adaptation and its possible relationships with TEs. However, crustaceans have been greatly underrepresented in transposable element studies. Using both degenerate PCR and in silico approaches, we have identified 35 Copia and 46 Gypsy families in 15 and 18 crustacean species, respectively. In particular, we characterized several full-length elements from the shrimp Rimicaris exoculata that is listed as a model organism from hydrothermal vents. Phylogenic analyses show that Copia and Gypsy retrotransposons likely present two opposite dynamics within crustaceans. The Gypsy elements appear relatively frequent and diverse whereas Copia are much more homogeneous, as 29 of them belong to the single GalEa clade, and species- or lineage-dependent. Our results also support the hypothesis of the Copia retrotransposon scarcity in metazoans compared to Gypsy elements. In such a context, the GalEa-like elements present an outstanding wide distribution among eukaryotes, from fishes to red algae, and can be even highly predominant within a large taxon, such as Malacostraca. Their distribution among crustaceans suggests a dynamics that follows a “domino days spreading” branching process in which successive amplifications may interact positively.

Esnault, Caroline; Graca, Paula; Higuet, Dominique; Bonnivard, Eric

2013-01-01

342

Glucose-sulfate conjugates as a new phase II metabolite formed by aquatic crustaceans.  

PubMed

We found that aquatic crustaceans, decapoda; atyidae (Caridina multidentata, Neocaridina denticulate, and Paratya compressa), metabolize pyrene to a new conjugation product. The results of deconjugation treatments indicated that glucose and sulfate combined with 1-hydroxypyrene. Further analysis by LC/ESI-MS/MS showed that the molecular weight of the product was 460 (m/z 459; deprotonated ion), and that it has a glucose-sulfate moiety (m/z 241; fragment ion). These results indicated that the new metabolite was the glucose-sulfate conjugate of 1-hydroxypyrene. The glucose-sulfate conjugate is a phase II product that has not been reported previously from any organism. Several studies have demonstrated that sulfation is an important pathway for metabolism of xenobiotics in aquatic invertebrates. Thus, glucose-sulfate conjugates may add an important signal for excretion or sequestration of xenobiotics for aquatic invertebrates. PMID:17603009

Ikenaka, Yoshinori; Ishizaka, Masumi; Eun, Heesoo; Miyabara, Yuichi

2007-08-24

343

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

344

Molecular cloning, characterization and recombinant expression of crustacean hyperglycemic hormone in white shrimp Litopenaeus vannamei.  

PubMed

Crustacean hyperglycemic hormone (CHH) plays an important role in crustacean. In the present study, a full-length cDNA of CHH was cloned from the eyestalk of Litopenaeus vannamei by RACE approach for the first time. The full-length cDNA of LvCHH was 846 bp, containing a 5' untranslated region (UTR) of 65 bp, a 3' UTR of 436 bp with a canonical polyadenylation signal-sequence AATAA and a poly (A) tail, and an open reading frame (ORF) of 345 bp. The ORF encoded a polypeptide of 114 amino acids including a 24 amino acid signal peptide. The calculated molecular mass of the mature protein (74 amino acids) was 8.76 kDa with an estimated pI of 6.78. The sequence of LvCHH was submitted in NCBI GenBank under the accession number HM748790.2. Phylogenetic analysis revealed that LvCHH was clustered with CHH of other crustaceans. Tissue distribution analysis revealed that the expression of LvCHH mRNA was observed in all tissues but gill, and was highest in heart. Specific primers containing Xho I and BamH I restriction sites respectively, were designed based on the obtained ORF sequence of LvCHH gene and the cloning sites of expression vector pET-32a (+). The recombinant plasmid LvCHH-pET32a, was used to transform Escherichia coli BL21 (DE3). LvCHH was successfully expressed by means of SDS-PAGE and western blot analysis. We detected gill Na(+)/K(+)-ATPase activity after rLvCHH protein injection and found that All the experimental group Na(+)/K(+)-ATPase activity presented peak change among 0-6h, and the peaks of all treated groups occurred in 1 h. 20 and 30 ?g/shrimp(-1) groups showed significant increase (P<0.05) in 1h post-injection. L. vannamei were exposed for 96h to hypo- and hyper-salinity challenge. Hypo-salinity caused a significant rise (P<0.05) in the mRNA expression of CHH and gill Na(+)/K(+)-ATPase activity at 12h and 24h respectively, then the CHH mRNA expression declining by 24h, and returned to control group level by 48 h, and the Na(+)/K(+)-ATPase activity tended to be stable after 72 h, and higher than that of control. The hyper-salinity challenge had the same trend at mRNA expression with the hypo-salinity group. The Na(+)/K(+)-ATPase activity had no significant change under the low salinity challenge. All these results indicate that LvCHH is an important hormone involved in the osmosis responses of swimming shrimps, and can provide further information of crustacean osmoregulation physiological mechanism. PMID:23954713

Liu, Maoqi; Pan, Luqing; Li, Li; Zheng, Debin

2014-03-01

345

Effects of osmotic shock on the ultrastructure of cell nuclei in euryhaline and stenohaline crustaceans.  

PubMed

Changes in cell ultrastructure in relation to volume regulation following application of osmotic challenges have been but poorly documented up to now. In a previous study, we demonstrated that large and immediate changes in the organization of nuclear chromatin occur in mammalian cells under such conditions. Similar chromatin modifications are shown in the present study in the cells of the stenohaline crab Maia verrucosa. They are not seen in the cells of the euryhaline species tested, hyperosmoregulating (Eriocheir sinensis) or osmoconforming (Cancer pagurus). Nor are they seen in cells of Portunus puber, another stenohaline species. These results are discussed in the context of the disrupting effects that inorganic ions have on macromolecular structures and of the protection which may be conferred by organic osmolytes used by various crustacean species. PMID:18621193

Gilles, R; Goffinet, G

1991-01-01

346

Long-term Lethal Toxicity Test with the Crustacean Artemia franciscana  

PubMed Central

Our research activities target the use of biological methods for the evaluation of environmental quality, with particular reference to saltwater/brackish water and sediment. The choice of biological indicators must be based on reliable scientific knowledge and, possibly, on the availability of standardized procedures. In this article, we present a standardized protocol that used the marine crustacean Artemia to evaluate the toxicity of chemicals and/or of marine environmental matrices. Scientists propose that the brine shrimp (Artemia) is a suitable candidate for the development of a standard bioassay for worldwide utilization. A number of papers have been published on the toxic effects of various chemicals and toxicants on brine shrimp (Artemia). The major advantage of this crustacean for toxicity studies is the overall availability of the dry cysts; these can be immediately used in testing and difficult cultivation is not demanded1,2. Cyst-based toxicity assays are cheap, continuously available, simple and reliable and are thus an important answer to routine needs of toxicity screening, for industrial monitoring requirements or for regulatory purposes3. The proposed method involves the mortality as an endpoint. The numbers of survivors were counted and percentage of deaths were calculated. Larvae were considered dead if they did not exhibit any internal or external movement during several seconds of observation4. This procedure was standardized testing a reference substance (Sodium Dodecyl Sulfate); some results are reported in this work. This article accompanies a video that describes the performance of procedural toxicity testing, showing all the steps related to the protocol.

Manfra, Loredana; Savorelli, Federica; Pisapia, Marco; Magaletti, Erika; Cicero, Anna Maria

2012-01-01

347

Mapping of Neuropeptides in the Crustacean Stomatogastric Nervous System by Imaging Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Considerable effort has been devoted to characterizing the crustacean stomatogastric nervous system (STNS) with great emphasis on comprehensive analysis and mapping distribution of its diverse neuropeptide complement. Previously, immunohistochemistry (IHC) has been applied to this endeavor, yet with identification accuracy and throughput compromised. Therefore, molecular imaging methods are pursued to unequivocally determine the identity and location of the neuropeptides at a high spatial resolution. In this work, we developed a novel, multi-faceted mass spectrometric strategy combining profiling and imaging techniques to characterize and map neuropeptides from the blue crab Callinectes sapidus STNS at the network level. In total, 55 neuropeptides from 10 families were identified from the major ganglia in the C. sapidus STNS for the first time, including the stomatogastric ganglion (STG), the paired commissural ganglia (CoG), the esophageal ganglion (OG), and the connecting nerve stomatogastric nerve ( stn) using matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) and the MS/MS capability of this technique. In addition, the locations of multiple neuropeptides were documented at a spatial resolution of 25 ?m in the STG and upstream nerve using MALDI-TOF/TOF and high-mass-resolution and high-mass-accuracy MALDI-Fourier transform ion cyclotron resonance (FT-ICR) instrument. Furthermore, distributions of neuropeptides in the whole C. sapidus STNS were examined by imaging mass spectrometry (IMS). Different isoforms from the same family were simultaneously and unambiguously mapped, facilitating the functional exploration of neuropeptides present in the crustacean STNS and exemplifying the revolutionary role of this novel platform in neuronal network studies.

Ye, Hui; Hui, Limei; Kellersberger, Katherine; Li, Lingjun

2013-01-01

348

The crustacean scavenger guild in Antarctic shelf, bathyal and abyssal communities  

NASA Astrophysics Data System (ADS)

Peracarid crustaceans form a significant part of the macrobenthic community that is responsible for scavenging on large food falls onto the sea floor. Although several studies are available about scavengers from tropical and temperate seas, very little information has been published about such species living in Antarctic waters, particularly at greater depths. The present paper is based on a collection of 31 baited trap sets deployed in the Weddell Sea, Scotia Sea, and off the South Shetland Islands, and presents results on the geographical and bathymetric distribution of the different taxa and on the eco-functional role of scavengers. Some 68,000 peracarid crustaceans from 62 species were collected. About 98% of individuals belonged to the amphipod superfamily Lysianassoidea, and 2% to the isopod family Cirolanidae. Of these species, 31, including 26 lysianassoids (1400 individuals), were collected deeper than 1000 m. High species richness was discerned for the eastern Weddell Sea shelf compared with other Antarctic areas. The Antarctic slope also seems to be richer in species than other areas investigated in the world, while in the abyss, scavenger species richness appears to be lower in Antarctica. A richness gradient was thus observed from the shelf to the deep. For amphipods, a number of species extend their distribution from the shelf to the slope and only one to the abyssal zone. Amphipod species showed degrees of adaptation to necrophagy. The functional adaptations of the mandible and the storage function of the gut are discussed. Feeding experiments conducted on lysianassoid species collected at great depths and maintained in aquaria showed a mean feeding rate of about 1.4-4.1% dry body weight day -1, which is consistent with data obtained from other species.

De Broyer, Claude; Nyssen, Fabienne; Dauby, Patrick

2004-07-01

349

Mapping of neuropeptides in the crustacean stomatogastric nervous system by imaging mass spectrometry  

PubMed Central

Considerable effort has been devoted to characterizing the crustacean stomatogastric nervous system (STNS) with great emphasis on comprehensive analysis and mapping distribution of its diverse neuropeptide complement. Previously, immunohistochemistry (IHC) has been applied to this endeavor yet with identification accuracy and throughput compromised. Therefore, molecular imaging methods are pursued to unequivocally determine the identity and location of the neuropeptides at a high spatial resolution. In this work, we developed a novel multi-faceted mass spectrometric strategy combining profiling and imaging techniques to characterize and map neuropeptides from the blue crab Callinectes sapidus STNS at the network level. In total, 55 neuropeptides from 10 families were identified from the major ganglia in the C. sapidus STNS for the first time, including the stomatogastric ganglion (STG), the paired commissural ganglia (CoG), the esophageal ganglion (OG), and the connecting nerve stomatogastric nerve (stn) using matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) and the MS/MS capability of this technique. In addition, the locations of multiple neuropeptides were documented at a spatial resolution of 25 ?m in the STG and upstream nerve using MALDI-TOF/TOF and high-mass-resolution and high-mass-accuracy MALDI-Fourier transform ion cyclotron resonance (FT-ICR) instrument. Furthermore, distributions of neuropeptides in the whole C. sapidus STNS were examined by imaging mass spectrometry (IMS). Different isoforms from the same family were simultaneously and unambiguously mapped, facilitating the functional exploration of neuropeptides present in the crustacean STNS and exemplifying the revolutionary role of this novel platform in neuronal network studies.

Ye, Hui; Hui, Limei; Kellersberger, Katherine; Li, Lingjun

2012-01-01

350

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

351

Synaptic neuropil in nerves of the crustacean stomatogastric nervous system: an immunocytochemical and electron microscopical study.  

PubMed

Patches of peptide-immunoreactive varicosities have been found in nerves of the stomatogastric nervous system (STNS) of decapod crustaceans. In the present study, these patches were examined in detail in the stomatogastric nerve (stn) and in the superior oesophageal nerve (son) of the crayfish Cherax destructor by using whole-mount immunocytochemical techniques combined with confocal microscopy and, in addition, electron microscopy. Double-labeling experiments with antibodies generated against the peptides allatostatin, FMRFamide and proctolin, combined with an antibody generated against the small vesicle protein synapsin, suggest that each patch contains small synaptic vesicles in addition to all three peptides. The neuropil regions of the ganglia of the STNS were also strongly stained by the synapsin antibody. Synapsin-like immunoreactivity was also studied in the crab Cancer pagurus and the lobster Homarus americanus. A similar pattern of staining was found for all three species, but the distribution within the stn varied. In H. americanus, a lightly stained weblike structure was found on the surface of nerves including the inferior oesophageal nerve, the son, and the anterior stn. By using electron microscopy, synapses were found in the core of the stn-son junction of C. destructor, in the same region where the synapsin-like and the peptide staining was localized. In addition, putative neurohemal release sites were found in the peripheral sheath of the stn. The presynaptic profiles found in the core of the stn seem to correspond to the types of presynaptic profiles found in the neuropil of the stomatogastric ganglion. These findings demonstrate that synaptic neuropil is present in the nerves of the STNS of a decapod crustacean. PMID:10754509

Skiebe, P; Ganeshina, O

2000-05-01

352

Ciliate Epibionts Associated with Crustacean Zooplankton in German Lakes: Distribution, Motility, and Bacterivory  

PubMed Central

Ciliate epibionts associated with crustacean zooplankton are widespread in aquatic systems, but their ecological roles are little known. We studied the occurrence of ciliate epibionts on crustacean zooplankton in nine German lakes with different limnological features during the summer of 2011. We also measured the detachment and re-attachment rates of the ciliates, changes in their motility, and the feeding rates of attached vs. detached ciliate epibionts. Epibionts were found in all lakes sampled except an acidic lake with large humic inputs. Epibiont prevalence was as high as 80.96% on the cladoceran Daphnia cucullata, 67.17% on the cladoceran Diaphanosoma brachyurum, and 46.67% on the calanoid copepod Eudiaptomus gracilis. Both cladoceran groups typically had less than 10 epibionts per individual, while the epibiont load on E. gracilis ranged from 1 to >30 epibionts per individual. After the death of the zooplankton host, the peritrich ciliate epibiont Epistylis sp. detached in an exponential fashion with a half-life of 5?min, and 98% detached within 30?min, leaving behind the stalks used for attachment. Immediately after detachment, the ciliates were immotile, but 62% became motile within 60?min. When a new host was present, only 27% reattached after 120?min. The average measured ingestion rate and clearance rate of Epistylis were 11,745 bacteria ciliate?1?h?1 and 24.33??l ciliate?1?h?1, respectively. Despite their high feeding rates, relatively low epibiont abundances were observed in the field, which suggests either diversion of energy to stalk formation, high metabolic loss by the epibionts, or high mortality among the epibiont populations.

Bickel, Samantha L.; Tang, Kam W.; Grossart, Hans-Peter

2012-01-01

353

Haemolymph Mg(2+) regulation in decapod crustaceans: physiological correlates and ecological consequences in polar areas.  

PubMed

Reptant decapod crustaceans are almost absent from the Southern Ocean south of the Antarctic Convergence. We tested the hypothesis that this may be due to the reduced ability of this group to regulate Mg(2+) levels in the haemolymph ([Mg(2+)](HL)). Mg(2+) acts as an anaesthetic in marine invertebrates and its level is higher in Reptantia (crabs such as Cancer spp., Chionoecetes spp., Maja spp., 30-50 mmol l(-)(1)) than in Natantia (prawns such as Pandalus spp., Palaemon spp., Crangon spp., 5-12 mmol l(-)(1)). We varied [Mg(2+)](HL) in three species of reptant decapod crustaceans, Carcinus maenas, Hyas araneus and Eurypodius latreillei, and investigated heart rate, the rate of oxygen consumption and levels of spontaneous and forced activity at different temperatures. The rate of oxygen consumption and heart rate increased significantly with reduction in [Mg(2+)](HL) over the entire temperature range investigated in E. latreillei. In H. araneus, an increase in metabolic and heart rates compared with control values was found only at temperatures below 2 degrees C. Forced and spontaneous activity levels increased significantly in the group of [Mg(2+)](HL)-reduced animals below 0 degrees C, at which control animals were mostly inactive. At a reduced [Mg(2+)](HL) of 5-12 mmol l(-)(1), which is the [Mg(2+)](HL) of caridean shrimps in the Southern Ocean, Q(10) and activation energy were reduced for all these variables and extended the temperature range over which physiological functions were maintained. We suggest that the high [Mg(2+)](HL) in Reptantia causes relaxation of the animals and reduces their scope for activity, especially at temperatures below 0 degrees C. The hypothesis that the synergistic effects of high [Mg(2+)](HL) and low temperature probably prevented the Reptantia from recolonizing the permanently cold water of polar areas is discussed. PMID:10729286

Frederich, M; Sartoris, F J; Arntz, W E; Pörtner, H

2000-04-01

354

Neurogenesis in the crustacean ventral nerve cord: homology of neuronal stem cells in Malacostraca and Branchiopoda?  

PubMed

In Insecta and malacostracan Crustacea, neurons in the ventral ganglia are generated by the unequal division of neuronal stem cells, the neuroblasts (Nbs), which are arranged in a stereotyped, grid-like pattern. In malacostracans, however, Nbs originate from ectoteloblasts by an invariant lineage, whereas Nbs in insects differentiate without a defined lineage by cell-to-cell interactions within the neuroectoderm. As the ventral ganglia in entomostracan crustaceans were thought to be generated by a general inward proliferation of ectodermal cells, the question arose as to whether neuroblasts in Euarthropoda represent a homologous type of stem cell. In the current project, neurogenesis in metanauplii of the entomostracan crustaceans Triops cancriformis Fabricius, 1780 (Branchiopoda, Phyllopoda) and Artemia salina Linné, 1758 (Branchiopoda, Anostraca) was examined by in vivo incorporation of the mitosis marker bromodeoxyuridine (BrdU) and compared to stem cell proliferation in embryos of the malacostracan Palaemonetes argentinus Nobili, 1901 (Eucarida, Decapoda). The developmental expression of synaptic proteins (synapsins) was studied immunohistochemically. Results indicate that in the ventral neurogenic zone of Branchiopoda, neuronal stem cells with cellular characteristics of malacostracan neuroblasts are present. However, a pattern similar to the lineage-dependent, grid-like arrangement of the malacostracan neuroblasts was not found. Therefore, the homology of entomostracan and malacostracan neuronal stem cells remains uncertain. It is now well established that during arthropod development, identical and most likely homologous structures can emerge, although the initiating steps or the mode of generation of these structures are different. Recent evidence suggests that adult Entomostraca and Malacostraca share corresponding sets of neurons so that the present report provides an example that those homologous neurons may be generated via divergent developmental pathways. In this perspective, it remains difficult at this point to discuss the question of common patterns of stem cell proliferation with regard to the phylogeny and evolution of Atelocerata and Crustacea. PMID:11440250

Harzsch, S

2001-01-01

355

The biological effects of antidepressants on the molluscs and crustaceans: A review.  

PubMed

Antidepressants are among the most commonly detected human pharmaceuticals in the aquatic environment. Since their mode of action is by modulating the neurotransmitters serotonin, dopamine, and norepinephrine, aquatic invertebrates who possess transporters and receptors sensitive to activation by these pharmaceuticals are potentially affected by them. We review the various types of antidepressants, their occurrence and concentrations in aquatic environments, and the actions of neurohormones modulated by antidepressants in molluscs and crustaceans. Recent studies on the effects of antidepressants on these two important groups show that molluscan reproductive and locomotory systems are affected by antidepressants at environmentally relevant concentrations. In particular, antidepressants affect spawning and larval release in bivalves and disrupt locomotion and reduce fecundity in snails. In crustaceans, antidepressants affect freshwater amphipod activity patterns, marine amphipod photo- and geotactic behavior, crayfish aggression, and daphnid reproduction and development. We note with interest the occurrence of non-monotonic dose responses curves in many studies on effects of antidepressants on aquatic animals, often with effects at low concentrations, but not at higher concentrations, and we suggest future experiments consider testing a broader range of concentrations. Furthermore, we consider invertebrate immune responses, genomic and transcriptomic sequencing of invertebrate genes, and the ever-present and overwhelming question of how contaminant mixtures could affect the action of neurohormones as topics for future study. In addressing the question, if antidepressants affect aquatic invertebrates at concentrations currently found in the environment, there is strong evidence to suggest the answer is yes. Furthermore, the examples highlighted in this review provide compelling evidence that the effects could be quite multifaceted across a variety of biological systems. PMID:24374179

Fong, Peter P; Ford, Alex T

2014-06-01

356

Rock Cycle: Cycling  

NSDL National Science Digital Library

This Science Object is the third of four Science Objects in the Rocks SciPack. It explores the variables that contribute to rock transformation and the continuous processes of rock formation that constitute the rock cycle. The rock cycle provides an example of the transfer of energy and mass in the Earth system. Earth is a closed system containing essentially a fixed amount of each element. Movement of matter is driven by the Earth's internal and external sources of energy, and is often accompanied by changes in the physical and chemical properties of the matter. Minerals are made, dissolved, and remade--on the Earth's surface, in the oceans, and in the hot, high-pressure layers beneath the crust. The total amount of material stays the same as its forms change. Learning Outcomes:� Recognize the formation and transformation processes as part of a continuing cycle.� Identify that while the form and location of different rocks change over time, the amount of material and the distribution among the elements remains constant.� Explain the different processes or paths that each type of rock may take in the rock cycle.

National Science Teachers Association (NSTA)

2006-11-01

357

Subsurface crustacean communities as proxy for groundwater-surface water interactions in the Henares and Tajuña Rivers floodplains, central Spain  

NASA Astrophysics Data System (ADS)

In the last decades, the linkage between surface water - groundwater via the hyporheic zone and the alluvial floodplains become more and more acknowledged. Hydrological exchanges between the stream and hyporheic zone ensure the transport of matter and energy and provide support for biogeochemical processes occurring in-stream bed sediments. Furthermore, the hyporheic zone is directly linked to permeable alluvial aquifers of which exchanges in both directions ensure the withstanding of a mixt biotic community's that may originate either from the surface benthic habitats or from the shallow aquifer. Data on the subsurface crustacean assemblages are used to infer the surface-groundwater interaction in two-groundwater fed-streams in central Spain. The survey was conducted on 20 hyporheic sites (20-40 cm depth) and 28 shallow or deep boreholes. Multivariate statistics were applied to test for differences in crustacean communities resulting from changes in water chemistry between the upstream and downstream parts of the alluvial aquifer, and between the hyporheic zone and the alluvial aquifer. Our aims were to: 1) test whether groundwater discharges in-stream bed sediments are reflected in changes in the crustacean assemblage's structure; and 2) establish whether the surface water influence decreases with increasing groundwater depth and distance from the river. We further aimed to test whether the diversity-stability ecotonal paradigm associated with the distinct level of disturbances and stability at the interface surface-groundwater and the aquifer is reflected in groundwater crustacean community structure. We start from the assumption that groundwater ecosystems undergo significant changes in space and time, and that classical groundwater stability hypothesis ought to be changed to concepts operative for surface ecosystems: disturbance and resilience. The streams are characterised by distinct gradients of surface-groundwater exchanges at spatial scale, with major interactions at the rivers headwaters compare to the lower part of the alluvial aquifer. The origin of the water in-stream bed sediments is indicated by water chemistry, whereas crustacean communities indicate surface-groundwater exchanges by modifications of the community's structure i.e., upwelling groundwater is indicated by large stygobites populations (obligate groundwater species), whereas downwelling surface waters is usually linked to mixed stygophiles and stygoxene populations. The downwelled surface water flow pattern has detectable influence on increasing nutrient content in shallow hyporheic waters and consequently, crustacean assemblages show distinctly high density and diversity. The crustacean diversity slightly declines with increasing depth, whereas no relationship with the population density was detected. The results obtained highlight the recognition of crustacean communities as alternative proxy to investigate surface water-groundwater exchanges. We concluded that the hydrological connections between surface water and groundwater had a major influence in shaping the crustacean communities structure by controlling the diversity, density and ecological configuration of these populations. In the perspective of increasing alteration of surface-groundwater exchanges due to human actions, both small and large scale monitoring surveys are critical for placing groundwater changes in quality and quantity into a wider context, in order to enhance the assessment of subsurface ecosystems sensitivity to anthropogenic forcing and consequently reduce the negative impact.

Rasines Ladero, Ruben; Iepure, Sanda; Careño, Francisco; de Bustamante, Irene

2013-04-01

358

Life Cycles  

NSDL National Science Digital Library

Students extend their knowledge of matter and energy cycles in organisms to engineering life cycle assessment of products. They learn about product life cycle assessment and the flow of energy through the cycle, comparing it to the flow of nutrients and energy in the life cycles of organisms.

Integrated Teaching And Learning Program

359

Potentiation of a novel palladium (II) complex lethality with bee venom on the human T-cell acute lymphoblastic leukemia cell line (MOLT-4)  

PubMed Central

Background Although honeybee venom (BV) has been reported to induce apoptosis in different types of cancerous cells, its synergistic effects with customary anti-cancer drugs remain largely unknown. In the present study, we evaluated the cytotoxic effect of BV alone (as a natural product) and the synergistic cytological effects of this component in combination with [Pd (bpy) (Pi-Pydtc)]NO3 – a novel palladium complex on human T-cell lymphoblastic leukemia cells. To investigate the cytotoxic effect of the BV alone and in combination with palladium complex on MOLT-4 cells MTT assay was performed. In order to determine the apoptotic effects of BV separately and in combination with Pd (II) complex on these cells and its ability to induce apoptosis, morphological examination, flowcytometric analysis and caspase-3 colorimetric assay were done. Results We found that BV induced morphological changes, namely nuclear shrinkage, and inhibited MOLT-4 cell proliferation; both effects were dose- and time-dependent. Flow cytometry by Annexin-V antibody demonstrated that BV induced apoptosis in MOLT-4 cells. Furthermore, BV induced apoptosis independently of caspase-3 in these cells. In addition, we proved a clear synergistic effect of BV on [Pd (bpy) (Pi-Pydtc)]NO3. The apoptotic pathway activated by BV in combination with Pd complex was caspase-3-dependent. Conclusions These observations provide an explanation for the anti-proliferative properties of BV, and suggest that this agent may be useful for treating lymphoblastic leukemia alone or in combination with chemotherapy drugs pending further investigations on animal models as preclinical tests.

2013-01-01

360

Abundance, composition, and distribution of crustacean zooplankton in relation to hypolimnetic oxygen depletion in west-central Lake Erie  

USGS Publications Warehouse

Samples of crustacean zooplankton were collected monthly in west-central Lake Erie in April and June to October 1968, and in July and August 1970, before and during periods of hypolimnetic dissolved oxygen (DO) depletion. The water column at offshore stations was thermally stratified from June through September 1968, and the hypolimnion contained no DO in mid-August of 1968 or 1970. Composition, abundance, and vertical distribution of crustacean zooplankton changed coincidentally with oxygen depletion. From July to early August, zooplankton abundance dropped 79% in 1968 and 50% in 1970. The declines were attributed largely to a sharp decrease in abundance of planktonic Cyclops bicuspidatus thomasi. Zooplankton composition shifted from mainly cyclopoid copepods in July to mainly cladocerans and copepod nauplii in middle to late August. We believe that mortality of adults and dormancy of copepodites in response to anoxia was the probable reason for the late summer decline in planktonic C. b. thomasi.

Heberger, Roy F.; Reynolds, James B.

1977-01-01

361

Molecular cloning and characterization of crustacean type-one dopamine receptors: D1?Pan and D1?Pan  

PubMed Central

Dopamine (DA) differentially modulates identified neurons in the crustacean stomatogastric nervous system (STNS). While the electrophysiological actions of DA have been well characterized, little is known about the dopaminergic transduction cascades operating in this system. As a first step toward illuminating the molecular underpinnings of dopaminergic signal transduction in the crustacean STNS, we have cloned and characterized two type-one DA receptors (DARs) from the spiny lobster (Panulirus interruptus): D1?Pan and D1?Pan. We found that the structure and function of these arthropod DARs are well conserved across species. Using a heterologous expression system, we determined that DA, but not serotonin, octopamine, tyramine or histamine activates these receptors. When stably expressed in HEK cells, the D1?Pan receptor couples with Gs, and DA elicits an increase in [cAMP]. The D1?Pan receptor responds to DA with a net increase in [cAMP] that is mediated by Gs and Gz.

Clark, Merry C.; Baro, Deborah J.

2014-01-01

362

[Localization of crustaceans--fish parasites and nose capsules as the habitat of the genus Salmincola (Podoplea: Lernaeopodidae) mesoparasites].  

PubMed

Copepoda parasitica of Baikal fishes (16 species) is divided into 7 groups according to their localization: parasites of the gill apparatus, gill covers, gill and buccal cavities, nasal fossa, cutaneous covering, and fins. It was proposed to separate nasal fossa parasites as the special ecological group ofmesoparasites. Typical speciemens of the group include crustaceans Salmincola longimanus complex--parasites of grayling and cisco fishes consist of three species (S. longimanus, S. svetlanovi, S. lavaretus) and one subspecies (S. longimanus sibirica). PMID:24455872

Pronin, N M; Burdukovskaia, T G

2013-01-01

363

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

364

Marine invertebrate collagens: The prevalence of type V and XI like collagens in some marine crustacean and molluscan tissues  

Microsoft Academic Search

While the invertebrates constitute almost 95% of the animal kingdom, our knowledge on their extracellular matrices, particularly\\u000a on collagen, is very scanty. Our group has been studying the collagen polymorphism in some marine invertebrate tissues with\\u000a focus on structure-function relationships and molecular evolution. We have established methods to purify unique collagen molecules\\u000a from some rare tissues of crustaceans and molluscs.

P Sivakumar; Gowri Chandrakasan

1999-01-01

365

Silent calcium channels in skeletal muscle fibers of the crustacean Atya lanipes.  

PubMed

The superficial (tonic) abdominal flexor muscles of Atya lanipes do not generate Ca(2+) action potentials when depolarized and have no detectable inward Ca(2+) current. These fibers, however, are strictly dependent on Ca(2+) influx for contraction, suggesting that they depend on Ca(2+)-induced Ca(2+) release for contractile activation. The nature of the communication between Ca(2+) channels in the sarcolemmal/tubular membrane and Ca(2+) release channels in the sarcoplasmic reticulum in this crustacean muscle was investigated. The effects of dihydropyridines on tension generation and the passive electrical response were examined in current-clamped fibers: Bay K 8644 enhanced tension about 100% but did not alter the passive electrical response; nifedipine inhibited tension by about 70%. Sr(2+) and Ba(2+) action potentials could be elicited in Ca(2+)-free solutions. The spikes generated by these divalent cations were abolished by nifedipine. As the Sr(2+) or Ba(2+) concentrations were increased, the amplitudes of the action potentials and their maximum rate of rise, V(max), increased and tended towards saturation. Three-microelectrode voltage-clamp experiments showed that even at high (138 mm) extracellular Ca(2+) concentration the channels were silent, i.e., no inward Ca(2+) current was detected. In Ca(2+)-free solutions, inward currents carried by 138 mm Sr(2+) or Ba(2+) were observed. The currents activated at voltages above -40 mV and peaked at about 0 mV. This voltage-activation profile and the sensitivity of the channels to dihydropyridines indicate that they resemble L-type Ca(2+) channels. Peak inward current density values were low, ca. -33 microA/cm(2) for Sr(2+) and -14 microA/cm(2) for Ba(2+), suggesting that Ca(2+) channels are present at a very low density. It is concluded that Ca(2+)-induced Ca(2+) release in this crustacean muscle operates with an unusually high gain: Ca(2+) influx through the silent Ca(2+) channels is too low to generate a macroscopic inward current, but increases sufficiently the local concentration of Ca(2+) in the immediate vicinity of the sarcoplasmic reticulum Ca(2+) release channels to trigger the highly amplified release of Ca(2+) required for tension generation. PMID:10612687

Monterrubio, J; Lizardi, L; Zuazaga, C

2000-01-01

366

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

2008-04-01

367

A new look at embryonic development of the visual system in decapod crustaceans: neuropil formation, neurogenesis, and apoptotic cell death.  

PubMed

In recent years, comparing the structure and development of the central nervous system in crustaceans has provided new insights into the phylogenetic relationships of arthropods. Furthermore, the structural evolution of the compound eyes and optic ganglia of adult arthropods has been discussed, but it was not possible to compare the ontogeny of arthropod visual systems, owing to the lack of data on species other than insects. In the present report, we studied the development of the crustacean visual system by examining neurogenesis, neuropil formation, and apoptotic cell death in embryos of the American lobster, Homarus americanus, the spider crab, Hyas araneus, and the caridean shrimp, Palaemonetes argentinus, and compare these processes with those found in insects. Our results on the patterns of stem cell proliferation provide evidence that in decapod crustaceans and hemimetabolous insects, there exist considerable similarities in the mechanisms by which accretion of the compound eyes and growth of the optic lobes is achieved, suggesting an evolutionary conservation of these mechanisms. PMID:10235683

Harzsch, S; Benton, J; Dawirs, R R; Beltz, B

1999-05-01

368

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

369

The effect of four levels of ascorbic acid and two levels of calcium on eggshell quality of forced-molted White Leghorn hens.  

PubMed

The present experiment evaluated the effect of four levels of ascorbic acid (0, 100, 250, and 500 ppm) and two levels of calcium (3.0 and 3.5%) on the productivity and eggshell quality of molted Single Comb White Leghorn hens, housed four per 30.5 cm wide x 45.7 cm deep cage. The 4 x 2 factorial treatment combinations were randomly assigned to eight blocks of cages. Egg production increased (P < .06) an average of 5% for the levels of 250 and 500 ppm ascorbic acid. No differences were observed for feed consumption, egg weight, and shell thickness for the different levels of ascorbic acid or calcium in the diet. An increase (P < .01) was observed for specific gravity, as the levels of ascorbic acid increased. Increasing the level of calcium from 3.0 to 3.5% increased (P < .01) specific gravity from 1.073 to 1.075. Shell weight increased (P < .01) with the higher levels of ascorbic acid (250 and 500 ppm). No interactions were observed between the levels of ascorbic acid and calcium. Results suggest that supplementing ascorbic acid to molted laying hens can be beneficial to egg production and eggshell quality. PMID:7644417

Zapata, L F; Gernat, A G

1995-06-01

370

Supplementation of dietary vitamins, protein and probiotics on semen traits and immunohistochemical study of pituitary hormones in zinc-induced molted broiler breeders.  

PubMed

The purpose of this study was to investigate the effect of dietary vitamin E and vitamin C, probiotics mixture and protein level and their combination on semen quality and immunohistochemical study of some pituitary hormones in male broiler breeders. One hundred and eighty male broiler breeders 65 weeks old were divided into six groups by completely randomized design. The birds were subjected to zinc-induced molt by mixing zinc oxide at the rate of 3000mg/kg in the feed. After molting, one group was fed control diet (CP16%). The other groups were fed vitamin E (100IU/kg), vitamin C (500IU/kg), probiotics (50mg/L of drinking water), protein (CP14%) and combination of these components. These treatments were given for five weeks. After the feeding period, semen samples were taken and analyzed for semen volume, sperm concentration, motility and dead sperm percentage. Pituitary samples were collected from three birds per replicate and were processed for immunohistochemical study. The results of semen quality parameters revealed that semen volume and sperm motility were significantly high in the vitamin E fed group, while the dead sperm percentage decreased significantly in the vitamin C group. The morphometric analysis revealed that compared to other groups, vitamin E caused a significant increase in the size and area of FSH, LH gonadotropes and lactotropes. These results showed that vitamin E alone may play some role in the enhancement of semen quality and growth of gonadotropes and lactotropes. PMID:23522908

Khan, Rifat Ullah; Rahman, Zia-ur-; Javed, Ijaz; Muhammad, Faqir

2013-09-01

371

Fecundity of the crustacean Mysidopsis californica (Mysida, Mysidae) under semi-controlled conditions.  

PubMed

Mysid crustaceans are frequently used in the laboratory to feed cephalopods and fish, but not along the Pacific coast, where they are scarce. There is no commercial aquaculture of mysids in the Pacific Ocean. To change this situation, we calculate fecundity, survival, and sex ratio of Mysidopsis californica under semi-controlled conditions. Mysids were collected manually using a 500 microm-mesh net along the rocky coast of Mazatlin, Sinaloa, Mexico. They were transferred to three 30 L seawater aquaria in the laboratory, and fed (ad libitum) Artemia nauplii and rotifers. Two generations were obtained. The relationship between the number of juveniles born and parent female lengths showed a rate of 1.56 juveniles released per each unit of increasing parent female length. An average parent female length of 6.92 mm (SD=0.82) gave 9.96 (SD=4.29) released juveniles. The frequency of female length showed a mean of 7.3 mm (SD=0.54), whereas that of juveniles showed a mean of 1.7 mm (SD=0.16). Survival and sex ratios (females-males) varied from 77.7% to 88.6% and 2.5:1 to 3.0:1, respectively. PMID:19256426

Ortega-Salas, Armando A; Núñez-Pastén, Arturo; Camacho, Humberto A

2008-06-01

372

Novel membrane-associated prostaglandin E synthase-2 from crustacean arthropods.  

PubMed

Prostaglandins (PG) have been shown to play important physiological roles in insects and marine invertebrates, yet the knowledge of their biosynthetic pathways is often lacking. Recently, we described cyclooxygenases in two amphipod crustaceans, Gammarus sp. and Caprella sp. In the present study, we report the cloning and characterization of prostaglandin E synthases (PGES) from the same organisms. The amphipod membrane-bound PGES-2-type enzymes share about 40% of the amino acid sequence identity with human mPGES-2, contain a conserved Cys110-x-x-Cys113 motif and have very low heme-binding affinity. The recombinant enzymes purified in the absence of dithiothreitol specifically catalyze the isomerization of PGH2 into PGE2. The PGES activity is increased in the presence of reduced glutathione and inhibited with a sulfhydryl group inhibitor. We assume that the amphipod mPGES-2, unlike in their mammalian counterparts, is responsible for PGE2 synthesis, not only in vitro but also in vivo. PMID:24947207

Hansen, Kristella; Varvas, Külliki; Järving, Ivar; Samel, Nigulas

2014-08-01

373

Mass Spectrometric Characterization and Physiological Actions of Novel Crustacean C-Type Allatostatins  

PubMed Central

The crustacean stomatogastric ganglion (STG) is modulated by numerous neuropeptides that are released locally in the neuropil or that reach the STG as neurohormones. Using 1,5-diaminonaphthalene (DAN) as a reductive screening matrix for matrix-assisted laser desorption/ionization (MALDI) mass spectrometric profiling of disulfide bond-containing C-type allatostatin peptides followed by electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) tandem mass spectrometric (MS/MS) analysis, we identified and sequenced a novel C-type allatostatin peptide (CbAST-C1), pQIRYHQCYFNPISCF-COOH, present in the pericardial organs of the crab, Cancer borealis. Another C-type allatostatin (CbAST-C2), SYWKQCAFNAVSCFamide, was discovered using the expressed sequence tag (EST) database search strategy in both C. borealis and the lobster, Homarus americanus, and further confirmed with de novo sequencing using ESI-Q-TOF tandem MS. Electrophysiological experiments demonstrated that both CbAST-C1 and CbAST-C2 inhibited the frequency of the pyloric rhythm of the STG, in a state-dependent manner. At 10?6M, both peptides were only modestly effective when initial frequencies of the pyloric rhythm were >0.8 Hz, but almost completely suppressed the pyloric rhythm when applied to preparations with starting frequencies < 0.7Hz. Surprisingly, these state-dependent actions are similar to those of the structurally unrelated allatostatin A and allatostatin B families of peptides.

Ma, Mingming; Szabo, Theresa M.; Jia, Chenxi; Marder, Eve; Li, Lingjun

2009-01-01

374

Seasonal distribution and abundance of fishes and decapod crustaceans in a Cape Cod estuary  

USGS Publications Warehouse

Sampling in several habitat types (sand/mud, eelgrass, sand, gravel, macroalgae/mud) during all seasons with a variety of gears in Nauset Marsh, Massachusetts during 1985-1987 found a fauna consisting of 35 fish and 10 decapod crustacean species. Although most of the abundant species were found in several habitat types, species richness and habitat use appeared to be highest for vegetated habitats (eelgrass, macroalgae). The fishes and decapods were numerically dominated by cold-water taxa; however, numerous fish species, represented by rare individuals of predominantly southern forms, enriched the fauna. Species composition of Nauset Marsh could be distinguished from estuaries south of Cape Cod and even from the south shore of the cape. Both fishes and decapods were most abundant during the summer, apparently due to the contributions from spring and summer spawning in the estuary and the adjacent Atlantic Ocean. The location of Nauset Marsh and other estuaries on Cape Cod provide a unique opportunity to evaluate the importance of this region as a faunal boundary to estuarine species.

Able, K.W.; Fahay, M.P.; Heck, K.L.; Roman, C.T.; Lazzari, M.A.; Kaiser, S.C.

2002-01-01

375

Measurement of crustacean hyperglycaemic hormone levels in the edible crab Cancer pagurus during emersion stress  

PubMed

The effects of emersion stress upon circulating hyperglycaemic hormone (CHH) levels in the edible crab Cancer pagurus were investigated using a highly specific and sensitive radioimmunoassay, with an antiserum directed against HPLC-purified C. pagurus CHH. Emersion resulted in hyperglycaemia and immediate hypoxia, as shown by rapid hyperlactaemia. CHH levels increased dramatically during the first hour of emersion, from almost undetectable levels to around 17 pmol l-1, thereafter increasing to around 30 pmol l-1 after 4 h of emersion. Short-term air exposure experiments demonstrated that significant increases in CHH levels (up to 3.5 pmol l-1) could be detected during the first 15 min of emersion. Although CHH appears to be fairly stable in haemolymph in vitro, injected CHH was cleared extremely rapidly from the haemolymph in vivo. The results suggest that emersion results in rapid, massive and prolonged exocytosis of CHH from the sinus gland. The sensitivity of the assay and the utility of this crab model may be useful in further studies to elucidate the control of CHH release in crustaceans. PMID:9319482

Webster

1996-01-01

376

Phylogenetic analysis of arthropods using two nuclear protein-encoding genes supports a crustacean + hexapod clade.  

PubMed Central

Recent phylogenetic analyses using molecular data suggest that hexapods are more closely related to crustaceans than to myriapods, a result that conflicts with long-held morphology-based hypotheses. Here we contribute additional information to this debate by conducting phylogenetic analyses on two nuclear protein-encoding genes, elongation factor-1 alpha (EF-1 alpha) and the largest subunit of RNA polymerase II (Pol II), from an extensive sample of arthropod taxa. Results were obtained from two data sets. One data set comprised 1092 nucleotides (364 amino acids) of EF-1 alpha and 372 nucleotides (124 amino acids) of Pol II from 30 arthropods and three lobopods. The other data set contained the same EF-1 alpha fragment and an expanded 1038-nucleotide (346-amino-acid) sample of Pol II from 17 arthropod taxa. Results from maximum-parsimony and maximum-likelihood analyses strongly supported the existence of a Crustacea + Hexapoda clade (Pancrustacea) over a Myriapoda + Hexapoda clade (Atelocerata). The apparent incompatibility between the molecule-based Pancrustacea hypothesis and morphology-based Atelocerata hypothesis is discussed.

Shultz, J W; Regier, J C

2000-01-01

377

Haplosporidium littoralis sp. nov.: a crustacean pathogen within the Haplosporida (Cercozoa, Ascetosporea).  

PubMed

Previously, we described the pathology and ultrastructure of an apparently asporous haplosporidian-like parasite infecting the common shore crab Carcinus maenas from the European shoreline. In the current study, extraction of genomic DNA from the haemolymph, gill or hepatopancreas of infected C. maenas was carried out and the small subunit ribosomal DNA (SSU rDNA) of the pathogen was amplified by PCR before cloning and sequencing. All 4 crabs yielded an identical 1736 bp parasite sequence. BLAST analysis against the NCBI GenBank database identified the sequence as most similar to the protistan pathogen group comprising the order Haplosporida within the class Ascetosporea of the phylum Cercozoa Cavalier-Smith, 1998. Parsimony analysis placed the crab pathogen within the genus Haplosporidium, sister to the molluscan parasites H. montforti, H. pickfordi and H. lusitanicum. The parasite infecting C. maenas is hereby named as Haplosporidium littoralis sp. nov. The presence of a haplosporidian parasite infecting decapod crustaceans from the European shoreline with close phylogenetic affinity to previously described haplosporidians infecting molluscs is intriguing. The study provides important phylogenetic data for this relatively understudied, but commercially significant, pathogen group. PMID:23999708

Stentiford, G D; Bateman, K S; Stokes, N A; Carnegie, R B

2013-09-01

378

Ultrastructural and mechanical properties of electrically inexcitable skeletal muscle fibers of the crustacean Atya lanipes.  

PubMed

Examination of the ultrastructure and mechanical activation of the ventro-abdominal flexor muscle of the freshwater crustacean Atya lanipes shows that the fibers are of the long sarcomere, tonic type. The fibers possess an ample and well-organized internal membrane system, with extensive regions of T/SR dyad contacts near the ends of the A bands. An orbit of 10-12 thin filaments surrounds each thick filament. The lanthanum tracer method reveals a highly regular organization of the T-system, Z-tubules, and multiple internal clefts. Tension generation responds to extracellular potassium in a concentration dependent manner and is very slow. Mechanical activation is strictly dependent on extracellular Ca2+, even though these muscle fibers do not generate Ca2+ currents when depolarized. Tension development responds to caffeine and is also dependent on extracellular Na+, suggesting that Ca2+ release from the SR and Ca2+ influx via the Na/Ca exchanger intervene in mechanical activation. PMID:1440577

Bonilla, M; García, M C; Orkand, P M; Zuazaga, C

1992-01-01

379

Ultraviolet radiation induces dose-dependent pigment dispersion in crustacean chromatophores.  

PubMed

Pigment dispersion in chromatophores as a response to UV radiation was investigated in two species of crustaceans, the crab Chasmagnathus granulata and the shrimp Palaemonetes argentinus. Eyestalkless crabs and shrimps maintained on either a black or a white background were irradiated with different UV bands. In eyestalkless crabs the significant minimal effective dose inducing pigment dispersion was 0.42 J/cm(2) for UVA and 2.15 J/cm(2) for UVB. Maximal response was achieved with 10.0 J/cm(2) UVA and 8.6 J/cm(2) UVB. UVA was more effective than UVB in inducing pigment dispersion. Soon after UV exposure, melanophores once again reached the initial stage of pigment aggregation after 45 min. Aggregated erythrophores of shrimps adapted to a white background showed significant pigment dispersion with 2.5 J/cm(2) UVA and 0.29 J/cm(2) UVC. Dispersed erythrophores of shrimps adapted to a black background did not show any significant response to UVA, UVB or UVC radiation. UVB did not induce any significant pigment dispersion in shrimps adapted to either a white or a black background. As opposed to the tanning response, which only protects against future UV exposure, the pigment dispersion response could be an important agent protecting against the harmful effects of UV radiation exposure. PMID:15357842

Gouveia, Glauce Ribeiro; Lopes, Thaís Martins; Neves, Carla Amorim; Nery, Luiz Eduardo Maia; Trindade, Gilma Santos

2004-10-01

380

Behaviour of fish by-catch in the mouth of a crustacean trawl.  

PubMed

The behaviour of fish by-catch was recorded and characterized by in situ observations in the mouth of a crustacean trawl using an underwater camera system with artificial light, at depths between 106 and 461 m, along the central coast of Chile. The groups or species studied were rattails (family Macrouridae), Chilean hake Merluccius gayi gayi, sharks (orders Carcharhiniformes and Squaliformes), skates (family Rajidae), flatfishes (genus Hippoglossina) and small benthopelagic and demersal fishes (orders Osmeriformes, Stomiiformes, Gadiformes, Ophidiiformes and Perciformes). The fish behaviour was categorized in terms of (1) position in the water column, (2) initial orientation with respect to the trawl, (3) locomotion and (4) swimming speed with respect to the trawl. Rattails, sharks, skates and flatfishes were passive in response to the trawl and showed similar behavioural patterns, with most fishes observed sitting or touching the bottom with no swimming or other activity. Merluccius gayi gayi was the most active species, displaying a wide combination of behavioural responses when the trawl approached. This species showed several behavioural patterns, mainly characterized by swimming forward at variable speed. A fraction of small bentho-pelagic and demersal fishes also showed an active behaviour but always at lower speed than the trawl. The species-specific differences in behaviour in the mouth of the trawl suggest that improvements at the level of the footrope can be made to reduce by-catch, especially of passive species. PMID:22650431

Queirolo, D; Gaete, E; Montenegro, I; Soriguer, M C; Erzini, K

2012-06-01

381

A mutation in the receptor Methoprene-tolerant alters juvenile hormone response in insects and crustaceans.  

PubMed

Juvenile hormone is an essential regulator of major developmental and life history events in arthropods. Most of the insects use juvenile hormone III as the innate juvenile hormone ligand. By contrast, crustaceans use methyl farnesoate. Despite this difference that is tied to their deep evolutionary divergence, the process of this ligand transition is unknown. Here we show that a single amino-acid substitution in the receptor Methoprene-tolerant has an important role during evolution of the arthropod juvenile hormone pathway. Microcrustacea Daphnia pulex and D. magna share a juvenile hormone signal transduction pathway with insects, involving Methoprene-tolerant and steroid receptor coactivator proteins that form a heterodimer in response to various juvenoids. Juvenile hormone-binding pockets of the orthologous genes differ by only two amino acids, yet a single substitution within Daphnia Met enhances the receptor's responsiveness to juvenile hormone III. These results indicate that this mutation within an ancestral insect lineage contributed to the evolution of a juvenile hormone III receptor system. PMID:23673641

Miyakawa, Hitoshi; Toyota, Kenji; Hirakawa, Ikumi; Ogino, Yukiko; Miyagawa, Shinichi; Oda, Shigeto; Tatarazako, Norihisa; Miura, Toru; Colbourne, John K; Iguchi, Taisen

2013-01-01

382

Resistance to a bacterial parasite in the crustacean Daphnia magna shows Mendelian segregation with dominance  

PubMed Central

The influence of host and parasite genetic background on infection outcome is a topic of great interest because of its pertinence to theoretical issues in evolutionary biology. In the present study, we use a classical genetics approach to examine the mode of inheritance of infection outcome in the crustacean Daphnia magna when exposed to the bacterial parasite Pasteuria ramosa. In contrast to previous studies in this system, we use a clone of P. ramosa, not field isolates, which allows for a more definitive interpretation of results. We test parental, F1, F2, backcross and selfed parental clones (total 284 genotypes) for susceptibility against a clone of P. ramosa using two different methods, infection trials and the recently developed attachment test. We find that D. magna clones reliably exhibit either complete resistance or complete susceptibility to P. ramosa clone C1 and that resistance is dominant, and inherited in a pattern consistent with Mendelian segregation of a single-locus with two alleles. The finding of a single host locus controlling susceptibility to P. ramosa suggests that the previously observed genotype–genotype interactions in this system have a simple genetic basis. This has important implications for the outcome of host–parasite co-evolution. Our results add to the growing body of evidence that resistance to parasites in invertebrates is mostly coded by one or few loci with dominance.

Luijckx, P; Fienberg, H; Duneau, D; Ebert, D

2012-01-01

383

Mitogenomic phylogenetic analysis supports continental-scale vicariance in subterranean thalassoid crustaceans.  

PubMed

Many continental subterranean water crustaceans ("stygobionts") display extreme disjunct distributions, where different species in the same genus are isolated on continents or islands separated by broad oceanic expanses. Despite their freshwater habitat, most of these taxa appear to be most closely related to typical marine groups ("thalassoid" origin). Among the hadzioids-thalassoid amphipods including the stygobiont families Hadziidae, Pseudoniphargidae, and Metacrangonyctidae-several genera are restricted to inland groundwaters ranging from the Caribbean region to the Mediterranean and Middle East, including interspersed oceanic islands. This distribution might have arisen from Tethyan vicariance triggered by the sequential occlusion of the former Tethys Sea, a vast circumtropical ocean existing from the Middle Jurassic up to 20 million years ago (mya). Previous studies have been based on morphological analyses or limited DNA sequence data, making it difficult to test this hypothesis. We used complete mitochondrial protein-coding gene sequences, mainly obtained by next-generation sequencing methods and a nuclear ribosomal gene to resolve the phylogeny and to establish a time frame for diversification of the family Metacrangonyctidae (Amphipoda). The results were consistent with the plate tectonics vicariance hypothesis, with major diversifications occurring between 96 and 83 mya. PMID:23063439

Bauzà-Ribot, Maria M; Juan, Carlos; Nardi, Francesco; Oromí, Pedro; Pons, Joan; Jaume, Damià

2012-11-01

384

Light and vision in the deep-sea benthos: II. Vision in deep-sea crustaceans.  

PubMed

Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of deep-sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497 nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (?(max)363 nm) and Gastroptychus spinifer (?(max)383 nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFF(max)). The CFF(max) for the isopod Booralana tricarinata of 4 Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the benthic environment. PMID:22956247

Frank, Tamara M; Johnsen, Sönke; Cronin, Thomas W

2012-10-01

385

Contents of carbohydrates and lipids in the bodies of two planktonic crustaceans  

NASA Astrophysics Data System (ADS)

The carbohydrate and lipid contents in two planktonic crustaceans, i. e. Pseudeuphausia sinica and Acetes chinensis sampled from Xiamen coastal waters were estimated. In P. sinica, the contents of carbohydrates (in dry weight) and lipids varied from 2.19 2.33% and 21.2 21.9% respectively; in A. chinensis from 1.74 2.55% and 14.43 15.10% respectively. The analyses of fatty acids by gas-chromatograph (Model 103) showed that eight fatty acids of 14?0, 15?0, 16?0, 17?0, 18?0, 18?2, 20?2 and 22?2 were found in these two animals, that 16?0, 18?0, 18?2, and 20?2 formed the major constituents with 91.08% ( P. sinica) and 74.80% ( A. chinensis) of the total fatty acids, and that the values of odd carbon types (15?0 and 17?0) were fairly low, 4.47% and 3.36% respectively. Three monosaccharides: glucose, fructose, and galactose detected by high-liquid chromatograph (Waters 208) accounted for more than 60% of the total carbohydrates, especially the glucose, exceeding by 40%.

Su, Yongquan; Yan, Hong; Zhang, Huan

1990-03-01

386

The trophic importance of algal turfs for coral reef fishes: the crustacean link  

NASA Astrophysics Data System (ADS)

On coral reefs, the epilithic algal matrix (EAM) is widely recognised as an important resource for herbivorous and detritivorous fishes. In comparison, little is known of the interaction between benthic carnivores and the EAM, despite the abundance of Crustacea within the EAM. The trophic importance of the EAM to fishes was investigated in Pioneer Bay, Orpheus Island, Great Barrier Reef. Fish densities were quantified using visual and clove oil censuses, and gut content analyses conducted on abundant fish species. Crustaceans were found to be an important dietary category, contributing between 49.5 and 100 % of the gut contents, with harpacticoid copepods being the dominant component. Of the benthic carnivores, the goby Eviota zebrina was found to consume the most harpacticoids with a mean of 249 copepods m-2 day-1. This represents approximately 0.1 % of the available harpacticoid population in the EAM. In a striking comparison, herbivorous parrotfishes were estimated to consume over 12,000 harpacticoids m-2 day-1, over 27 times more than all benthic carnivores surveyed, representing approximately 5.3 % of the available harpacticoid copepod population each day. The high consumption of harpacticoid copepods by benthic carnivores and parrotfishes indicates that harpacticoids form an important trophic link between the EAM and higher trophic levels on coral reefs.

Kramer, M. J.; Bellwood, O.; Bellwood, D. R.

2013-06-01

387

Accumulation of dioxins in deep-sea crustaceans, fish and sediments from a submarine canyon (NW Mediterranean)  

NASA Astrophysics Data System (ADS)

Submarine canyons are efficient pathways transporting sediments and associated pollutants to deep sea. The objective of this work was to provide with the first assessment of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) levels and accumulation in deep-sea megafauna (crustacean and fish) and sediments in the Blanes submarine canyon (North-Western Mediterranean Sea). The influence of the selected species habitats (pelagic, nektobenthic, and benthic) and the trophic chain level on the accumulation of dioxins was also investigated. Bottom sediment and biota samples were collected at different depths and locations inside the canyon and in the adjacent slope outside the canyon influence. ?2,3,7,8-PCDD/F concentrations in sediments varied from 102 to 680 pg g-1 dry weight (d.w.) (1-6 WHO98-TEQ pg g-1 d.w.). Dioxins are enriched in bottom sediments at higher depths inside the canyon and in particular in the deepest parts of the canyon axis (1700 m depth), whereas no enrichment of dioxins was verified at the deepest sediments from the adjacent open slope outside the canyon influence. The proportion of ?2,3,7,8-PCDF (furans) to ?2,3,7,8-PCDD (dioxins) increased for sediments with higher soot carbon content consistent with the higher affinity of PCDF for sorption onto soot carbon. Higher ?2,3,7,8-PCDD/F levels were found in crustaceans than in fish, ranging from 220 to 795 pg g-1 lipid weight (l.w.) (13-90 WHO98-TEQ pg g-1 l.w.) and 110 to 300 pg g-1 l.w. (22-33 WHO98-TEQ pg g-1 l.w.) in crustaceans and fish, respectively. Dioxin highest concentrations were found in nektobenthic organisms, i.e., benthic organism with swimming capabilities (both fish and crustaceans). These higher levels are consistent with the higher trophic level and predicted biomagnification factors (BMFs) of nektobenthic species. The reduced availability of sediment-bound PCDD/F for benthic species mainly due to soot and organic carbon sorption of these contaminants most probably influenced this result too. While biomagnification exerts a clear influence on the total dioxin concentrations in biota, life habits seem to exert an influence in the differential congener-specific accumulation of dioxins rather than in the total concentration. Thus, pelagic species reflected the estimated congener pattern from the surface water dissolved phase and phytoplankton, whereas the dioxin pattern in benthic and nektobenthic species was more similar to the estimated pattern in the deep-water dissolved phase and the sediment. The three crustacean species considered in this study bioaccumulated higher amounts of other dioxin congeners (non-2,3,7,8-PCDD/Fs) compared to fish. An interplay of several factors, such as biota habitats, differential uptake of water column dioxin (dissolved and particle-bound fractions), and different metabolization capabilities and rates (CYP-mediated metabolism) may explain the differences observed in dioxin patterns among crustacean species and between fish and crustaceans in the Blanes submarine canyon.

Castro-Jiménez, Javier; Rotllant, Guiomar; Ábalos, Manuela; Parera, Jordi; Dachs, Jordi; Company, Joan B.; Calafat, Antoni; Abad, Esteban

2013-11-01

388

Effects of temperature on photoperiodically induced reproductive development, circulating plasma luteinizing hormone and thyroid hormones, body mass, fat deposition and molt in mountain white-crowned sparrows, Zonotrichia leucophrys oriantha.  

PubMed

The mountain white-crowned sparrow, Zonotrichia leucophrys oriantha, breeds in subalpine meadows throughout many mountainous regions of western North America. Mathematical analysis of 20 years of egg-laying dates at Tioga Pass, California (3030m elevation) indicated a highly predictable breeding season suggesting that precise environmental cues such as the annual change in day length were important for regulating reproductive function. Additionally, it appeared that there was sufficient yearly variation in the timing of breeding to suggest that other environmental cues may also be important for regulating adjustments in reproductive development and regression. Captive populations of Z. l. oriantha showed strong responses in gonadal development following transfer to longs days (15L 9D) and low temperature (5 degrees C) slowed down photoperiodically induced gonadal growth and subsequent regression, in both males and females. High temperature of 30 degrees C tended to accelerate gonadal development and regression whereas gonadal development was intermediate in a group exposed to 20 degrees C. Prior exposure to these temperature regimes while on short days (9L 15D) had no effect on body mass, fat, or plasma levels of luteinizing hormone (LH) and thyroid hormones. Curiously there was no effect of temperature on photoperiodically induced rises in LH in either sex despite marked effects on gonadal growth. Brood patch development was also enhanced in females exposed to 30 degrees C. Corticosterone levels measured in a subset of plasma samples from this experiment indicated no effect of temperature suggesting that the retarded gonadal development at 5 degrees C was not a result of thermal stress. Although there was a robust effect of photostimulation on thyroid hormone levels in blood of both sexes, temperature treatment had no effect on tri-iodothyronine (T3) concentrations. However, plasma levels of thyroxine (T4) were lower initially at 5 degrees C versus 20 and 30 degrees C treatments. This may be related to the protracted gonadal cycle at 5 degrees C versus the truncated gonadal cycle at 30 degrees C. Molt score, an indication of post-reproductive state and onset of photorefractoriness, was delayed in birds exposed to 5 degrees C. Body mass, and to a lesser extent fat score, tended to be lowest in birds exposed to 5 degrees C compared with those at 20 and 30 degrees C. These results demonstrate that ambient temperature significantly affected photoperiodically induced gonadal development and regression in these birds. The endocrine mechanisms underlying these effects require further study. PMID:12679091

Wingfield, John C; Hahn, Thomas P; Maney, Donna L; Schoech, Stephan J; Wada, Masaru; Morton, Martin L

2003-04-01

389

Rock Cycle  

NSDL National Science Digital Library

This interactive Flash animation about the rock cycle is suitable for a review or overview in an introductory level Physical Geology class. It includes animations, photos, and descriptions involving rock types and processes in the rock cycle.

Smoothstone; Company, Houghton M.

390

Menstrual Cycle  

MedlinePLUS

... This information in Spanish ( en español ) The menstrual cycle Day 1 starts with the first day of ... levels drop at the end of the previous cycle, signaling blood and tissues lining the uterus (womb) ...

391

Biogeochemical Cycling  

NASA Technical Reports Server (NTRS)

This lecture will introduce the concept of biogeochemical cycling. The roles of microbes in the cycling of nutrients, production and consumption of trace gases, and mineralization will be briefly introduced.

Bebout, Brad; Fonda, Mark (Technical Monitor)

2002-01-01

392

Vitellogenin is not an appropriate biomarker of feminisation in a Crustacean.  

PubMed

The expression of the yolk protein vitellogenin (Vtg) has been used as a biomarker of feminisation in multiple fish species throughout the world. Since the late 1990s, researchers have attempted to develop similar biomarkers to address whether reproductive endocrine disruption also occurs in the males of invertebrate groups such as the Crustacea. To date, the vast majority of studies investigating Vtg induction in male Crustacea have resulted in negative or inconclusive results, leading researchers to question the utility of Vtg expression as a biomarker in this taxon. This study measured the expression of Vtg genes in two intersex phenotypes (termed internal and external) found in the male amphipod, Echinogammarus marinus, and compared them with those of normal males and females. Males presenting the external intersex phenotype are infected with known feminising parasites and display a variety of feminised traits including oviduct structures on their testes and external female brood plates (oostegites). The internal intersex male phenotype, that displays a pronounced oviduct structure on the testes without the external intersex characteristics, is not parasite infected and it is thought to be a result of environmental contamination. Given their morphology, these phenotypes might be considered highly 'feminised' or 'de-masculinised' and can be utilised to test the suitability of feminisation biomarkers. The E. marinus transcriptome was searched for genes resembling Vtg and two sequences were revealed, that we subsequently refer to as Vtg1 and Vtg2. Results from a high-throughput transcriptomic sequencing screen of gonadal cDNA libraries suggested that very low expression (in this manuscript gene transcription is taken to represent gene expression, although it is acknowledged that in addition to transcription, translation, transcript processing, mRNA stability and protein stability can regulate gene expression) of Vtg1 and Vtg2 in normal males (ESTs=1 and 0 for Vtg1 and Vtg2, respectively), internal intersex males (ESTs=0 for both Vtg sequences) and external intersex males (ESTs=5 and 0 for Vtg1 and Vtg2, respectively). In contrast, the sequencing suggested notable levels of expression of both Vtg genes in females (ESTs=1133 and 84 for Vtg1 and Vtg2, respectively). Subsequent qPCR analysis validates these expression levels, with the signal for Vtg1 and Vtg2 transcripts in all male phenotypes being indistinguishable from that caused by contamination of trace levels of genomic DNA or the low-level amplification non-target sequences. These findings suggest that Vtg expression is not notably induced in highly feminised amphipods and is therefore not an appropriate biomarker of feminisation/de-masculination in crustaceans. We discuss our findings in the context of previous attempts to measure Vtg in male crustaceans and suggest a requirement for more appropriate taxon-specific biomarkers to monitor feminisation in these groups. PMID:24342352

Short, Stephen; Yang, Gongda; Kille, Peter; Ford, Alex T

2014-08-01

393

Simultaneous sampling of flow and odorants by crustaceans can aid searches within a turbulent plume.  

PubMed

Crustaceans such as crabs, lobsters and crayfish use dispersing odorant molecules to determine the location of predators, prey, potential mates and habitat. Odorant molecules diffuse in turbulent flows and are sensed by the olfactory organs of these animals, often using a flicking motion of their antennules. These antennules contain both chemosensory and mechanosensory sensilla, which enable them to detect both flow and odorants during a flick. To determine how simultaneous flow and odorant sampling can aid in search behavior, a 3-dimensional numerical model for the near-bed flow environment was created. A stream of odorant concentration was released into the flow creating a turbulent plume, and both temporally and spatially fluctuating velocity and odorant concentration were quantified. The plume characteristics show close resemblance to experimental measurements within a large laboratory flume. Results show that mean odorant concentration and it's intermittency, computed as dc/dt, increase towards the plume source, but the temporal and spatial rate of this increase is slow and suggests that long measurement times would be necessary to be useful for chemosensory guidance. Odorant fluxes measured transverse to the mean flow direction, quantified as the product of the instantaneous fluctuation in concentration and velocity, v'c', do show statistically distinct magnitude and directional information on either side of a plume centerline over integration times of <0.5 s. Aquatic animals typically have neural responses to odorant and velocity fields at rates between 50 and 500 ms, suggesting this simultaneous sampling of both flow and concentration in a turbulent plume can aid in source tracking on timescales relevant to aquatic animals. PMID:24300599

Pravin, Swapnil; Reidenbach, Matthew A

2013-01-01

394

Genome anatomy of the gastrointestinal pathogen, Vibrio parahaemolyticus of crustacean origin  

PubMed Central

Vibrio parahaemolyticus, an important human pathogen, is associated with gastroenteritis and transmitted through partially cooked seafood. It has become a major concern in the production and trade of marine food products. The prevalence of potentially virulent and pathogenic V. parahaemolyticus in raw seafood is of public health significance. Here we describe the genome sequence of a V. parahaemolyticus isolate of crustacean origin which was cultured from prawns in 2008 in Selangor, Malaysia (isolate PCV08-7). The next generation sequencing and analysis revealed that the genome of isolate PCV08-7 has closest similarity to that of V. parahaemolyticus RIMD2210633. However, there are certain unique features of the PCV08-7 genome such as the absence of TDH-related hemolysin (TRH), and the presence of HU-alpha insertion. The genome of isolate PCV08-7 encodes a thermostable direct hemolysin (TDH), an important virulence factor that classifies PCV08-7 isolate to be a serovariant of O3:K6 strain. Apart from these, we observed that there is certain pattern of genetic rearrangements that makes V. parahaemolyticus PCV08-7 a non-pandemic clone. We present detailed genome statistics and important genetic features of this bacterium and discuss how its survival, adaptation and virulence in marine and terrestrial hosts can be understood through the genomic blueprint and that the availability of genome sequence entailing this important Malaysian isolate would likely enhance our understanding of the epidemiology, evolution and transmission of foodborne Vibrios in Malaysia and elsewhere.

2013-01-01

395

Hematodinium sp. (Alveolata, Syndinea) detected in marine decapod crustaceans from waters of Denmark and Greenland.  

PubMed

Five decapod crustacean species were examined for presence of the parasitic dinoflagellate Hematodinium spp. (Alveolata, Syndinea) by morphological methods (colour and pleopod methods) as well as by PCR and nested PCR with Hematodinium-specific primers. Nephrops norvegicus, Pagurus bernhardus and Liocarcinus depurator were sampled by trawling in Danish waters and Chionoecetes opilio and Hyas araneus were sampled by trapping off the west coast of Greenland. The existence of Hematodinium has not previoiusly been documented in Danish waters, but it was detected in all 3 decapod species examined in the present study. Hematodinium sp. was also detected for the first time in H. araneus and the existence of Hematodinium sp. in Greenlandic C. opilio was documented by PCR. Analyses of 26 Hematodinium sp. ITS1 sequences, including sequences from all 5 host species sampled, revealed more than 95% sequence similarity between 24 of the sequences. Two Hematodinium sp. ITS1 sequences from C. opilio were only 81% similar to the 24 other ITS1 sequences. The nested PCR approach resulted in the highest reported percentages of positive samples for Hematodinium sp.in the hosts investigated (between 45 and 87.5%). However, no decapods were found to be infected with Hematodinium sp. based on morphological methods. Consequently, Hematodinium sp. may be more common than previously believed, and, assuming that the DNA found originated from viable and infectious parasite cells, infections may not always be fatal. We suggest that the hosts investigated may have been subject to latent infections that could develop into a fatal disease only if the hosts were physiologically stressed due to other factors. PMID:21166315

Eigemann, F; Burmeister, A; Skovgaard, A

2010-10-26

396

Identification of GYRKPPFNGSIFamide (crustacean-SIFamide) in the crayfish Procambarus clarkii by topological mass spectrometry analysis.  

PubMed

A new concept relating to the purification protocol for biological proteins and peptides has been designed as "topological mass spectrometry analysis," in combination with MALDI-TOF MS using slices of tissues, chromatographic purification from the extract of tissues, molecular cloning for the determination of the precursor structure, and capillary LC-MS/MS analysis for elucidation of its posttranslational modifications. In an actual application, we identified an alpha-amidated neuropeptide from the red swamp crayfish (Procambarus clarkii) brain. Initially, an MS number of around m/z 1382 was found by the direct MALDI-TOF MS analysis with slices of the accessory lobe of the brain. After two steps of reversed-phase HPLC separation with brain extract, the structure of a 1381 Da peptide was sequenced to the GYRKPPFNGSIFamide (named crustacean-SIFamide). Subsequently, the cDNA has been characterized and encodes a 76 amino acid precursor protein that contains a signal sequence, one copy of GYRKPPFNGSIFG and one additional peptide. The RT-PCR analysis implied that the mRNA of the neuropeptide was expressed throughout the nervous system of the crayfish. Furthermore, immunostaining demonstrated that the neuropeptide is distributed in the olfactory lobe, accessory lobe, olfactory globular tract, and olfactory lobe cells. In addition, database searches revealed that there are homologous sequences of the AYRKPPFNGSIFamide in the genome library of fruitfly Drosophila melanogaster and AYRKPPFNGSLFamide isolated from the grey fleshfly Neobellieria bullata, and GYRKPPFNGSIFamide isolated from the giant tiger prawn Penaeus monodon. These results suggested that the neuropeptide family might be widely distributed in arthropods and plays a significant role in the nervous system. PMID:14723891

Yasuda, Akikazu; Yasuda-Kamatani, Yoshimi; Nozaki, Masumi; Nakajima, Terumi

2004-02-01

397

Unusual duplication of the insulin-like receptor in the crustacean Daphnia pulex  

PubMed Central

Background The insulin signaling pathway (ISP) has a key role in major physiological events like carbohydrate metabolism and growth regulation. The ISP has been well described in vertebrates and in a few invertebrate model organisms but remains largely unexplored in non-model invertebrates. This study is the first detailed genomic study of this pathway in a crustacean species, Daphnia pulex. Results The Daphnia pulex draft genome sequence assembly was scanned for major components of the ISP with a special attention to the insulin-like receptor. Twenty three putative genes are reported. The pathway appears to be generally well conserved as genes found in other invertebrates are present. Major findings include a lower number of insulin-like peptides in Daphnia as compared to other invertebrates and the presence of multiple insulin-like receptors (InR), with four genes as opposed to a single one in other invertebrates. Genes encoding for the Dappu_InR are likely the result of three duplication events and bear some unusual features. Dappu_InR-4 has undergone extensive evolutionary divergence and lacks the conserved site of the catalytic domain of the receptor tyrosine kinase. Dappu_InR-1 has a large insert and lacks the transmembranal domain in the ?-subunit. This domain is also absent in Dappu_InR-3. Dappu_InR-2 is characterized by the absence of the cystein-rich region. Real-time q-PCR confirmed the expression of all four receptors. EST analyses of cDNA libraries revealed that the four receptors were differently expressed under various conditions. Conclusions Duplications of the insulin receptor genes might represent an important evolutionary innovation in Daphnia as they are known to exhibit extensive phenotypic plasticity in body size and in the size of defensive structures in response to predation.

2010-01-01

398

Nucleic acid content in crustacean zooplankton: bridging metabolic and stoichiometric predictions.  

PubMed

Metabolic and stoichiometric theories of ecology have provided broad complementary principles to understand ecosystem processes across different levels of biological organization. We tested several of their cornerstone hypotheses by measuring the nucleic acid (NA) and phosphorus (P) content of crustacean zooplankton species in 22 high mountain lakes (Sierra Nevada and the Pyrenees mountains, Spain). The P-allocation hypothesis (PAH) proposes that the genome size is smaller in cladocerans than in copepods as a result of selection for fast growth towards P-allocation from DNA to RNA under P limitation. Consistent with the PAH, the RNA:DNA ratio was >8-fold higher in cladocerans than in copepods, although 'fast-growth' cladocerans did not always exhibit higher RNA and lower DNA contents in comparison to 'slow-growth' copepods. We also showed strong associations among growth rate, RNA, and total P content supporting the growth rate hypothesis, which predicts that fast-growing organisms have high P content because of the preferential allocation to P-rich ribosomal RNA. In addition, we found that ontogenetic variability in NA content of the copepod Mixodiaptomus laciniatus (intra- and interstage variability) was comparable to the interspecific variability across other zooplankton species. Further, according to the metabolic theory of ecology, temperature should enhance growth rate and hence RNA demands. RNA content in zooplankton was correlated with temperature, but the relationships were nutrient-dependent, with a positive correlation in nutrient-rich ecosystems and a negative one in those with scarce nutrients. Overall our results illustrate the mechanistic connections among organismal NA content, growth rate, nutrients and temperature, contributing to the conceptual unification of metabolic and stoichiometric theories. PMID:24466118

Bullejos, Francisco José; Carrillo, Presentación; Gorokhova, Elena; Medina-Sánchez, Juan Manuel; Villar-Argaiz, Manuel

2014-01-01

399

Mitogenomic analysis of decapod crustacean phylogeny corroborates traditional views on their relationships.  

PubMed

Phylogenetic relationships within decapod crustaceans are highly controversial. Even recent analyses based on molecular datasets have shown largely contradictory results. Previous studies using mitochondrial genomes are promising but suffer from a poor and unbalanced taxon sampling. To fill these gaps we sequenced the (nearly) complete mitochondrial genomes of 13 decapod species: Stenopus hispidus, Polycheles typhlops, Panulirus versicolor, Scyllarides latus, Enoplometopus occidentalis, Homarus gammarus, Procambarus fallax f. virginalis, Upogebia major, Neaxius acanthus, Calocaris macandreae, Corallianassa coutierei, Cryptolithodes sitchensis, Neopetrolisthes maculatus, and add that of Dromia personata. Our new data allow for comprehensive analyses of decapod phylogeny using the mitochondrial genomes of 50 species covering all major taxa of the Decapoda. Five species of Stomatopoda and one species of Euphausiacea serve as outgroups. Most of our analyses using Maximum Likelihood (ML) and Bayesian inference (BI) of nucleotide and amino acid datasets revealed congruent topologies for higher level decapod relationships: (((((((Anomala, Brachyura), Thalassinida: Gebiidea), Thalassinida: Axiidea), (Astacidea, Polychelida), Achelata), Stenopodidea), Caridea), Dendrobranchiata). This result corroborates several traditional morphological views and adds new perspectives. In particular, the position of Polychelida is surprising. Nevertheless, some problems can be identified. In a minority of analyses the basal branching of Reptantia is not fully resolved, Thalassinida are monophyletic; Polychelida are the sister group to Achelata, and Stenopodidea are resolved as sister group to Caridea. Despite this and although some nodal supports are low in our phylogenetic trees, we think that the largely stable topology of the trees regardless of different types of analyses suggests that mitochondrial genomes show good potential to resolve the relationship within Decapoda. PMID:23202543

Shen, Hong; Braband, Anke; Scholtz, Gerhard

2013-0