Crab Claw Research Articles

Validation of gibberellin synthetic pathway of rhizobia

CRABS CLAW (CRC) is a YABBY transcription factor that plays a pivotal role in carpel development and flower meristem determinacy. Here, we characterized a CRC homolog SlCRCa and elucidated its specific roles in tomato (Solanum lycopersicum). SlCRCa is highly expressed in the petals and stamens, and is responsive to gibberellin (GA) treatment. Overexpression of SlCRCa in tomato reduces the sizes of petals, stamens, and fruits, while the inverse phenotypes are induced by knockdown of SlCRCa. Furthermore, histological investigation suggests that the smaller or larger fruits in SlCRCa-overexpressing or SlCRCa-RNAi plants are mainly determined by the decreases or increases in cell layers and cell sizes in pericarp, respectively. Through transcriptome and qRT-PCR analyses, we speculate that SlCRCa inhibits cell division by regulating the transcription of cell division-related genes, and also suppresses cell expansion by modulating the expansin genes and GA pathway in tomato fruits. Besides, SlCRCa is involved in the feedback regulation of GA biosynthesis. Our findings reveal that SlCRCa negatively regulates fruit size by affecting cell division and cell expansion, and it is also an inhibitor of floral organ sizes in tomato.

Detailed spectroscopic study of the role of Br and Sr in coloured parts of the Callinectes sapidus crab claw.

The exoskeleton of crustaceans consists mainly of calcium carbonate (CaCO3) minerals and in many cases exhibits vivid colouration due to the presence of proteins rich in carotenoid chromophores. The exposure of aquatic animals in sea water results often in the incorporation of trace elements in their exoskeleton. The bonding configuration of Br and Sr trace elements in regions with different staining (white, orange and blue) of the exoskeleton of the Callinectes sapidus in crab claw are systematically investigated by a number of complementary spectroscopic techniques, including X-ray absorption fine structure spectroscopy (EXAFS), X-ray fluorescence, Raman and visible light reflectivity spectroscopies. It is found that Sr substitutes for Ca and the Sr/Ca ratio is constant along the claw. In the orange region that includes the claw fingers, CaCO3 adopts a calcite-like structure, whereas in the blue and white regions, located in the palm of the claw, an aragonite-like structure dominates. On the other hand, Br, present only in the blue and orange stained parts of the claw, is bound to phenyl and/or phenol rings of amino acid residues, most probably to phenylalanine and/or tyrosine, of the chromophore protein.

Organelle Size Scaling of the Budding Yeast Vacuole by Relative Growth and Inheritance

It has long been noted that larger animals have larger organs compared to smaller animals of the same species, a phenomenon termed scaling [1]. Julian Huxley proposed an appealingly simple model of "relative growth"-in which an organ and the whole body grow with their own intrinsic rates [2]-that was invoked to explain scaling in organs from fiddler crab claws to human brains. Because organ size is regulated by complex, unpredictable pathways [3], it remains unclear whether scaling requires feedback mechanisms to regulate organ growth in response to organ or body size. The molecular pathways governing organelle biogenesis are simpler than organogenesis, and therefore organelle size scaling in the cell provides a more tractable case for testing Huxley's model. We ask the question: is it possible for organelle size scaling to arise if organelle growth is independent of organelle or cell size? Using the yeast vacuole as a model, we tested whether mutants defective in vacuole inheritance, vac8Δ and vac17Δ, tune vacuole biogenesis in response to perturbations in vacuole size. In vac8Δ/vac17Δ, vacuole scaling increases with the replicative age of the cell. Furthermore, vac8Δ/vac17Δ cells continued generating vacuole at roughly constant rates even when they had significantly larger vacuoles compared towild-type. With support from computational modeling, these results suggest there is no feedback between vacuole biogenesis rates and vacuole or cell size. Rather, size scaling is determined by the relative growth rates of the vacuole and the cell, thus representing a cellular version of Huxley's model.

Crab Claw Sign as Indication of Malignancy for Small GGO (1 cm) to Receive Surgery

Crab Claw Sign as Indication of Malignancy for Small GGO (1 cm) to Receive Surgery

Bone Disease in Myeloma: The Claws of CRAB.

A dynamic approach to use bisphosphonates according to biomarkers of bone metabolism is presented in the Z-MARK study by Raje and colleagues. This is a major step forward toward a rational approach to bisphosphonate usage.

Collaborative study on determination of mono methylmercury in seafood

Eight laboratories participated in an inter-laboratory method-performance (collaborative) study of a method for the determination of mono methylmercury (MMHg) in foodstuffs of marine origin by gas chromatography inductively coupled plasma isotope dilution mass spectrometry (GC–ICP-IDMS) after dissolution, derivatisation and extraction of the species. The method was tested on seven seafood products covering both a wide concentration range and variations in the MMHg concentrations as well as matrix compositions. The samples were mussel tissue, squid muscle, crab claw meat, whale meat, cod muscle, Greenland halibut muscle and dogfish liver (NRCC DOLT-4), with MMHg concentrations ranging from 0.035 to 3.58mg/kg (as Hg) dry weight. Repeatability relative standard deviations (RSDr) for MMHg ranged from 2.1% to 8.7%. Reproducibility relative standard deviations (RSDR) ranged from 5.8% to 42%. All samples showed HorRat value below 1.0, except for the sample with the lowest MMHg content, mussel tissue, with a HorRat value of 1.6.

Effects of claw autotomy on green crab (Carcinus maenas) feeding rates

The European green crab (Carcinus maenas) is a voracious non-indigenous predator and a threat to Atlantic Canada's shellfish industry. Its foraging ability, however, may be affected by the occurrence of injuries such as the loss of a cheliped (claw). Given that green crab claws are differentiated into a major crusher and a minor cutter, we argue that autotomy (the reflexive loss of a limb) affects feeding rates, and that this effect depends on which particular claw is lost. We examined the incidence of injuries in two green crab populations of the southern Gulf of St. Lawrence during July–October, 2012. Then we experimentally assessed the influence of the loss of each type of claw upon crab feeding rates over two size-classes of American oysters (Crassostrea virginica) and soft-shell clams (Mya arenaria). Field injury surveys showed that 12.4% of the green crabs collected were missing a claw (the cutter and/or crusher claw). Injury rates increased linearly with crab size, and were found to vary with location. Laboratory experiments showed that, compared to intact crabs, the loss of the crusher claw reduced oyster mortality rates by ~93–100%. The loss of the crusher also reduced feeding on small soft-shell clams but only temporarily. The loss of the cutter claw had little impact on green crab feeding rates on oysters and soft-shell clams of either size. Combined, these results suggest that the loss of a claw has an effect on the ability of green crabs to consume commercially important species but this effect depends on which claw is lost and which prey is targeted. It follows that injury rates should be taken into consideration when monitoring and forecasting the potential impacts of green crab populations, particularly on oyster beds.

Dispatches

Dispatches

Does claw morphology of the green crab Carcinus maenas vary in relation to its diet on rocky versus fine-sediment shores of southwest New Brunswick, Bay of Fundy, Canada?

Inter-specific variation in claw morphology of decapod crustaceans is related to the particular dietary niche different species occupy, but very few studies have investigated whether claw variation among populations of a same species is similarly related to diet. We set out to quantify differences in claw morphology between green crabs inhabiting rocky and fine-sediment shores in the southwest Bay of Fundy, Canada, and asked whether these were related to differences in the prevalence of hard- and soft-bodied prey in the crab's diet. We found that claw morphology did not differ between crabs from the two habitat types, but did significantly differ between crabs sampled from different rocky shores and different fine-sediment shores. The absence of significant differences in claw morphology between crabs from rocky and fine-sediment shores was somewhat surprising, given that we did observe significant differences in crab diet between the two habitats. However, these dietary differences were related to the prevalence of soft-bodied prey, and hard-bodied snails and mussels were the most prevalent prey items in the guts of crabs from both rocky and fine-sediment shores. Our results therefore suggest that the prevalence of soft-bodied prey in the diet of green crabs in nature does not affect the morphology of their claw. Given our findings, along with recently published patterns of phenotypic co-variance between green crab claw size and snail shell thickness, we hypothesize that consumption of hard-bodied prey may be more consequential to variation in green crab claw morphology than the diet as a whole. More field studies are needed to complement the rich tradition of lab-based research into the biochemical properties of the decapod claw, and in particular to elucidate the role of diet on intra-specific variation of this appendage in nature.

Comparison of Scheimpflug Imaging Analysis of Pellucid Marginal Corneal Degeneration and Keratoconus

Aim: To determine and compare various quantitative parameters of pellucid marginal degeneration (PMD) and keratoconus with against-the-rule astigmatism (KC-ARA) obtained by elevation-based Scheimpflug imaging and to identify characteristics that can be used to discriminate PMD from KC-ARA. Setting: Ophthalmology Clinic, Ministry of Health Ankara Training and Research Hospital, Ankara, Turkey. Design: Retrospective case-control study. Patients and Methods: Patients with ARA, a butterfly or crab claw pattern in the curvature maps, a kissing bird pattern in the elevation maps and the bell sign in the pachymetric maps were identified, and 60 eyes of 40 patients were chosen for the evaluation. The patients were divided into two groups: the PMD group (29 eyes of 18 patients) and the KC-ARA group (31 eyes of 22 patients). By moving the cursor manually, the pachymetric maps and Scheimpflug images were searched for a thinner location than the automatically identified thinnest location. The coordinates and thickness of this manually identified location were evaluated. Results: In the PMD group, 7 (24.1%) eyes did not have any thinner location than the automatically identified thinnest location on the pachymetric maps and the Scheimpflug images, and in 22 (75.8%) eyes, a thinner location, which was located more peripherally, was found by manual evaluation of the pachymetric maps or Scheimpflug images. In 9 (31.0%) eyes of these 22, the manually identified thinnest locations were visible on pachymetric maps, and in 13 (44.8%) eyes the more peripheral thinnest locations were not visible on pachymetric maps but on Scheimpflug images. In the KC group, no patients had thinner locations than the automatically identified thinnest points on the pachymetric maps and the Scheimpflug images. Conclusion: A more peripheral thinner location than the automatically identified thinnest location exists in most of the eyes with PMD. In KC-ARA eyes, a thinner location than the automatically found thinnest point does not exist. Accordingly, a more peripheral thinner point than the identified thinnest point is a very strong indication for PMD. © 2014 S. Karger AG, Basel

Effect of CRC::etr1-1 transgene expression on ethylene production, sex expression, fruit set and fruit ripening in transgenic melon (Cucumis melo L.).

Ethylene is a key factor regulating sex expression in cucurbits. Commercial melons (Cucumis melo L.) are typically andromonoecious, producing male and bisexual flowers. Our prior greenhouse studies of transgenic melon plants expressing the dominant negative ethylene perception mutant gene, etr1-1, under control of the carpel- and nectary-primordia targeted CRAB'S CLAW (CRC) promoter showed increased number and earlier appearance of carpel-bearing flowers. To further investigate this phenomenon which could be potentially useful for earlier fruit production, we observed CRC::etr1-1 plants in the field for sex expression, fruit set, fruit development, and ripening. CRC::etr1-1 melon plants showed increased number of carpel-bearing open flowers on the main stem and earlier onset by 7-10 nodes. Additional phenotypes observed in the greenhouse and field were conversion of approximately 50% of bisexual buds to female, and elongated ovaries and fruits. Earlier and greater fruit set occurred on the transgenic plants. However, CRC::etr1-1 plants had greater abscission of young fruit, and smaller fruit, so that final yield (kg/plot) was equivalent to wild type. Earlier fruit set in line M5 was accompanied by earlier appearance of ripe fruit. Fruit from line M15 frequently did not exhibit external ripening processes of rind color change and abscission, but when cut open, the majority showed a ripe or overripe interior accompanied by elevated internal ethylene. The non-ripening external phenotype in M15 fruit corresponded with elevated etr1-1 transgene expression in the exocarp. These results provide insight into the role of ethylene perception in carpel-bearing flower production, fruit set, and ripening.

The structural basis of the Tle4-Tli4 complex reveals the self-protection mechanism of H2-T6SS in Pseudomonas aeruginosa.

The type VI secretion system (T6SS) has recently been demonstrated to mediate interbacterial competition and to discriminate between self and nonself. T6SS(+) bacteria employ toxic effectors to inhibit rival cells and concurrently use effector cognate immunity proteins to protect their sibling cells. The effector and immunity pairs (E-I pairs) endow the bacteria with a great advantage in niche competition. Tle4-Tli4 (PA1510-PA1509) is a newly identified E-I pair that is controlled by H2-T6SS in Pseudomonas aeruginosa. Tle4 exhibits phospholipase activity, which destroys the cell membrane of rival cells, and the periplasm-located Tli4 in donor cells eliminates this toxic effect of Tle4. In this paper, the structure of the Tle4-Tli4 complex is reported at 1.75 Å resolution. Tle4 consists of two domains: a conserved α/β-hydrolase domain and an unusual cap domain in which two lid regions (lid1 and lid2) display a closed conformation that buries the catalytic triad in a deep funnel. Tli4 also displays a two-domain structure, in which a large lobe and a small lobe form a crab claw-like conformation. Tli4 uses this crab claw to grasp the cap domain of Tle4, especially the lid2 region, which prevents the interfacial activation of Tle4 and thus causes enzymatic dysfunction of Tle4 in sister cells.

The Dietary and Reproductive Consequences of Fishery-Related Claw Removal for the Stone CrabMenippespp.

ABSTRACT The stone crab, Menippe spp. (Say, 1918), fishery is a large fishery in the southeastern United States. One of the primary regulations for this fishery requires that fisherman only harvest crab claws and return the living crab to the ocean. This regulation was put in place in an effort to reduce the overall mortality of harvested organisms and to promote fishery sustainability; however, fishery-related claw loss is likely to influence the population through multiple pathways. How fishery-related claw loss influenced stone crab diet choice, prey size selection, and consumption over time was examined, in addition to how these factors may influence the reproduction of harvested individuals. The consumption of soft-bodied prey, such as polychaete worms, was not influenced by claw loss. In contrast, claw loss has strong negative impacts on the consumption of more common hard-bodied prey, such as bivalves. Specifically, 1-clawed stone crabs consumed bivalves that were approximately 15% smaller after cl...

Cervical foraminal steroid injections under CT guidance: retrospective study of in situ contrast aspects in a serial of 248 cases.

To describe all the CT findings after in situ contrast injection just before steroid injection and to recognize the abnormal aspects associated with intravascular contamination. We retrospectively evaluated 248 cervical transforaminal steroid injections done at the university hospital in Dijon, France, in 2008-2012, to treat cervicobrachial neuralgia inadequately improved by optimal medical treatment for at least 3weeks. Features describing the opacification patterns were recorded. Five main nonvascular opacification patterns were identified: clumps of contrast agent outside the foramen (16%), a crab claw pattern surrounding the ganglion (13%), a "French" circumflex accent pattern (15%), reflux along the needle (7%), and facet joint capsule opacification (22%). Concerning the situations requiring a change in needle position, intravenous injection occurred in 26% of the patients, with a crab claw pattern in half the cases and a clump pattern in half the cases. Intraarteriolar injection was noted in two patients. CT after in situ contrast injection ensures proper needle positioning outside the blood vessels before steroid injection. Penetration of the needle tip into a vein is very common, whereas arteriolar puncture is extremely rare.

Floral primordia-targeted ACS (1-aminocyclopropane-1-carboxylate synthase) expression in transgenic Cucumis melo implicates fine tuning of ethylene production mediating unisexual flower development.

Floral primordia-targeted expression of the ethylene biosynthetic gene, ACS , in melon suggests that differential timing and ethylene response thresholds combine to promote carpels, inhibit stamens, and prevent asexual bud formation. Typical angiosperm flowers produce both male and female reproductive organs. However, numerous species have evolved unisexuality. Melons (Cucumis melo L.) can produce varying combinations of male, female or bisexual flowers. Regardless of final sex, floral development begins with sequential initiation of all four floral whorls; unisexuality results from carpel or stamen primordia arrest regulated by the G and A loci, respectively. Ethylene, which promotes femaleness, is a key factor regulating sex expression. We sought to further understand the location, timing, level, and relationship to sex gene expression required for ethylene to promote carpel development or inhibit stamen development. Andromonoecious melons (GGaa) were transformed with the ethylene biosynthetic enzyme gene, ACS (1-aminocyclopropane-1-carboxylate synthase), targeted for expression in stamen and petal, or carpel and nectary, primordia using Arabidopsis APETALA3 (AP3) or CRABSCLAW (CRC) promoters, respectively. CRC::ACS plants did not exhibit altered sex phenotype. AP3::ACS melons showed increased femaleness manifested by gain of a bisexual-only phase not seen in wild type, decreased male buds and flowers, and loss of the initial male-only phase. In extreme cases, plants became phenotypically hermaphrodite, rather than andromonoecious. A reduced portion of buds progressed beyond initial whorl formation. Both the ACS transgene and exogenous ethylene reduced the expression of the native carpel-suppressing gene, G, while elevating expression of the stamen-suppressing gene, A. These results show ethylene-mediated regulation of key sex expression genes and suggest a mechanism by which temporally regulated ethylene production and differential ethylene response thresholds can promote carpels, inhibit stamens, and prevent the formation of asexual buds.

The CRC orthologue from Pisum sativum shows conserved functions in carpel morphogenesis and vascular development.

CRABS CLAW (CRC) is a member of the YABBY family of transcription factors involved in carpel morphogenesis, floral determinacy and nectary specification in arabidopsis. CRC orthologues have been functionally characterized across angiosperms, revealing additional roles in leaf vascular development and carpel identity specification in Poaceae. These studies support an ancestral role of CRC orthologues in carpel development, while roles in vascular development and nectary specification appear to be derived. This study aimed to expand research on CRC functional conservation to the legume family in order to better understand the evolutionary history of CRC orthologues in angiosperms. CRC orthologues from Pisum sativum and Medicago truncatula were identified. RNA in situ hybridization experiments determined the corresponding expression patterns throughout flower development. The phenotypic effects of reduced CRC activity were investigated in P. sativum using virus-induced gene silencing. CRC orthologues from P. sativum and M. truncatula showed similar expression patterns, mainly restricted to carpels and nectaries. However, these expression patterns differed from those of other core eudicots, most importantly in a lack of abaxial expression in the carpel and in atypical expression associated with the medial vein of the ovary. CRC downregulation in pea caused defects in carpel fusion and style/stigma development, both typically associated with CRC function in eudicots, but also affected vascular development in the carpel. The data support the conserved roles of CRC orthologues in carpel fusion, style/stigma development and nectary development. In addition, an intriguing new aspect of CRC function in legumes was the unexpected role in vascular development, which could be shared by other species from widely diverged clades within the angiosperms, suggesting that this role could be ancestral rather than derived, as so far generally accepted.

Analysis of Key Odor Compounds in Steamed Chinese Mitten Crab (<i>Eriocheir sinensis</i>)

Key odor compounds in different edible parts (abdomen, claw, leg meat and gonad) of steamed female Chinese mitten crab (Eriocheir sinensis) were extracted by a new type of adsorbent (MonoTrap), identified by gas chromatography-mass spectrometry (GC-MS) and determined by gas chromatography-olfactometry (GC-O). Ninteen key odor compounds (odor intensity value≥3) were obtained in Chinese mitten crab, among which trimethylamine (fishy), (Z)-4-heptenal (fishy) and 2-ethylpyridine (roasted potato) were found in all four edible parts of Eriocheir sinensis. In addition, 8 KOCs (2-ethylfuran, benzaldehyde, 1-octen-3-ol, 6-methyl-2-heptanone, 2-pentylfuran, (E,E)-3,5-octadien-2-one, nonanal and decanal) were also identified in the abdomen meat, 5 KOCs (toluene, 2,5-dimethylpyrazine, 1-octen-3-ol, (E,E)-3,5-octadien-2-one and 2-methylnaphthalene) in the claw meat, 3 KOCs (toluene, 2-nonanone and nonanal) in the leg meat, and 12 KOCs (1-penten-3-ol, toluene, hexanal, 1,3,5-octatriene, benzaldehyde, 1-octen-3-ol, 6-methyl-2-heptanone, 2-pentylfuran, (E,E)-3,5-octadien-2-one, nonanal, (E,Z)-2,6-nonadienal and decanal) in the gonad part.

Application of electron spin resonance spectroscopy for the detection of irradiated crustaceans (prawn, shrimp, and crabs)

Prawn, shrimp and crabs sold in Japan are mostly imported from overseas. Detection of irradiated crustaceans is very important for quality assurance. In this study, we used ESR to detect radiation-induced radicals after irradiation of prawn, shrimp and crabs of major species. No radiation-induced radicals were detected in prawn (black tiger prawn) or shrimp (white leg shrimp). Radiation-induced radicals due to hydroxyapatite were detected in the claws of snow crab, red king crab, and swimming crab. Our results indicate that ESR measurement on the claw parts of these three species of crab can be used to determine their irradiation history.

Anatomic changes and treatment strategy of crab claw like Polydactyly of the thumb

Objective To observe the pathological anatomy of crab claw hke polydactyly of the thumb,analyze the possible mechanical mechanism and propose surgical strategies based on their treatment outcomes.Methods The intraoperative findings and X-ray morphology of 36 cases of crab claw hke polydactyly were analyzed.Based on the prevalent pathological deformity,modified Bilhaut-Cloquet technique was used to correct the deformity and reconstruct the thumb.Osteotomy and tendon insertion reattachment was done to re-align the axis.Results Crab claw hke polydactyly of the thumb had a typical 'S' shape and reverse 'S' shape appearance.There were different degrees of lateral angulations of both the IP joint and MP joint.In addition there was rotational deformity of the MP joint.The duplicate thumbs shared extensor and flexor tendons.The extensor tendon bifurcated at the level of the MP joint,while the flexor tendon bifurcated at the level of the IP joint.Both tendons terminated at the lateral aspect of the distal phalanx base.All the thenar muscles inserted at the radial side of the proximal phalanx base.Modified Bilhaut-Cloquet technique was used to correct the deformities.The result was satisfactory in 30 cases.Five cases were revised because of alignment shift.One case was revised because of double nail deformity.Conclusion The crab claw like polydactyly thumb is generally smaller than a normal thumb.The modified Bilhaut-Cloquet should be the major surgical procedure for reconstruction.Abnormal insertion of the tendons as well as bone and joim malformation are the two major causes for alignment shift.Osteotomy and tendon insertion reconstruction should be routinely adopted. Key words: Hand deformities, congenital; Surgical procedures, operative; Treatment outcome

A general skew-t mixed model that allows different degrees of freedom for random effects and error distributions

This paper develops a robust mixed model that assumes a multivariate skew-t distribution for random effects and an independent multivariate t-distribution for errors. It simultaneously captures skewness and heavy tailedness in data, while allowing the random effects and error distributions to have different degrees of freedom. It is fit using an EM-type algorithm. Simulations show that its efficiency for estimating mean response is comparable to that of the recent skew-t mixed model. But it may be considerably more efficient than the latter for estimating variance–covariance parameters when at least one of the random effects distribution or the error distribution has heavy tails, possibly due to outliers. The proposed model is used to analyze a data set consisting of lengths of claws of fiddler crabs (Uca mjoebergi).