Brachyuran Crustaceans Research Articles

Virome Analysis Provides an Insight into the Viral Community of Chinese Mitten Crab Eriocheir sinensis.

Recent advances in viromics have led to the discovery of a great diversity of RNA viruses and the identification of a large number of viral pathogens. A systematic exploration of viruses in Chinese mitten crab (Eriocheir sinensis), one of the most important aquatic commercial species, is still lacking. Here, we characterized the RNA viromes of asymptomatic, milky disease (MD)-affected, and hepatopancreatic necrosis syndrome (HPNS)-affected Chinese mitten crabs collected from 3 regions in China. In total, we identified 31 RNA viruses belonging to 11 orders, 22 of which were first reported here. By comparing viral composition between samples, we observed high variation in viral communities across regions, with most of the viral species being region-specific. We proposed to establish several novel viral families or genera based on the phylogenetic relationships and genome structures of viruses discovered in this study, expanding our knowledge of viral diversity in brachyuran crustaceans. IMPORTANCE High-throughput sequencing and meta-transcriptomic analysis provide us with an efficient tool to discover unknown viruses and explore the composition of viral communities in specific species. In this study, we investigated viromes in asymptomatic and diseased Chinese mitten crabs collected from three distant locations. We observed high regional variation in the composition of viral species, highlighting the importance of multi-location sampling. In addition, we classified several novel and ICTV-unclassified viruses based on their genome structures and phylogenetic relationships, providing a new perspective on current viral taxa.

A review of viral diseases in cultured brachyuran crustaceans

A review of viral diseases in cultured brachyuran crustaceans

A pheromone bouquet controls the reproductive behaviour of the male shore crab, Carcinus maenas

The reproduction of many brachyuran crustaceans involves the formation of mating pairs often around the time of the female moult with attraction of a sexual partner and mating behaviour controlled by sex pheromones. In shore crabs, Carcinus maenas, females produce sex pheromones that are released in the urine. High Performance Liquid Chromatography analysis (HPLC) of female urine shows that the pheromone, identified as the nucleotide uridine diphosphate (UDP), elutes as an unresolved peak with structurally related nucleotides. We examined female urine samples over the moult cycle and detected UDP as well as uridine triphosphate (UTP). Bioassays were conducted to establish the possibility of a blend of nucleotides forming a sex pheromone bouquet in C. maenas. Whilst UDP induced the male mate guarding behaviour (cradling), a mixture of the two nucleotides at a ratio of 4:1 UDP:UTP elicited an even stronger mating response than either UDP or UTP individually. The urine concentration and composition of these nucleotides changes over the moult period pre and post ecdysis, providing evidence that a pheromone bouquet composition is not always constant. The change of the bouquet is related to the physiological state of the sender, here the moult cycle. Our study unravels the functionality of reaction-specific molecules in a pheromone bouquet. Whilst UDP is the mating signal, UTP acts as an attractant and combined they maximise the reproductive response. The use of bouquets provides species-specificity, potentially enabling reproductive isolation of sympatric species, and contains valuable information on the physiological state of the sender.

Individual Laterality in Ghost Crabs (Ocypode saratan) Influences Burrowing Behavior

Behavioral handedness is known to enhance an individual’s handling capabilities. However, the ecological advantages in brachyuran crustaceans remain unclear, despite the Ocypode species having been studied extensively. Thus, in this study, we analyzed the laterality of the endemic Red Sea ghost crab on one beach in Eilat, Israel. We successfully documented the laterality of the large cheliped in 125 crabs; in 60 (48.0%), the right cheliped was larger, and in 64 (51.2%), the left. We also observed temporal segregation between the right- and left-clawed crabs. The right-handed crabs start activity just after sunrise, while left-handed crabs appear ca. 40 min after it. Similarly, temporal segregations were also observed in the evening. The right-clawed crab activity peaked ca. 20 min before sunset, while the left-clawed crabs were active uniformly. Additionally, burrow entrances corresponded to the larger cheliped of the resident individual and is probably a self-defense-related behavior. We conclude that cheliped laterality in O. saratan populations should be considered as a bimodal trait, where left- and right-handedness is not under natural selection pressure.

Diversity and classification of reoviruses in crustaceans: A proposal

A variety of reoviruses have been described in crustacean hosts, including shrimp, crayfish, prawn, and especially in crabs. However, only one genus of crustacean reovirus - Cardoreovirus - has been formally recognized by ICTV (International Committee on Taxonomy of Viruses) and most crustacean reoviruses remain unclassified. This arises in part from ambiguous or incomplete information on which to categorize them. In recent years, increased availability of crustacean reovirus genomic sequences is making the discovery and classification of crustacean reoviruses faster and more certain. This minireview describes the properties of the reoviruses infecting crustaceans and suggests an overall classification of brachyuran crustacean reoviruses based on a combination of morphology, host, genome organization pattern and phylogenetic sequence analysis.

Early Cretaceous (late Barremian) Crustacea from Puebla, Mexico

The oldest record of fossil decapods, associated to reefs from Mexico is reported. Six species of Anomala and brachyuran crustaceans, collected from limestones of the upper Barremian Zapotitlán Formation, Puebla, Mexico: Luisogalathea cretacea (Stenzel, 1945); Eomunidopsis limonitica (Stenzel, 1945); Paragalathea ruizi Van Straelen, 1940; Goniodromites laevis (Van Straelen, 1940); Distefania sp.; and Cretamaja klompmakeri González-León and Moreno-Bedmar, new species, are reported. This assemblage bears similarities with crustaceans reported from the upper Albian of the Pawpaw Shale of Texas and to other reef crustaceans from the Late Jurassic and Early Cretaceous of Europe. This is first record in the Americas for some genera. The here reported specimens are found associated to sponges, corals, mollusks and bryozoans, that suggest a shallow marine reef environment for this region of Central Mexico during late Barremian times. All of the specimens represent isolated dorsal carapaces, some with evidence of little transport.

An atlas of larval organogenesis in the European shore crab Carcinus maenas L. (Decapoda, Brachyura, Portunidae)

BackgroundThe life history stages of brachyuran crustaceans include pelagic larvae of the Zoea type which grow by a series of moults from one instar to the next. Zoeae actively feed and possess a wide range of organ systems necessary for autonomously developing in the plankton. They also display a rich behavioural repertoire that allows for responses to variations in environmental key factors such as light, hydrostatic pressure, tidal currents, and temperature. Brachyuran larvae have served as distinguished models in the field of Ecological Developmental Biology fostering our understanding of diverse ecophysiological aspects such as phenotypic plasticity, carry-over effects on life-history traits, and adaptive mechanisms that enhance tolerance to fluctuations in environmental abiotic factors. In order to link such studies to the level of tissues and organs, this report analyses the internal anatomy of laboratory-reared larvae of the European shore crab Carcinus maenas. This species has a native distribution extending across most European waters and has attracted attention because it has invaded five temperate geographic regions outside of its native range and therefore can serve as a model to analyse thermal tolerance of species affected by rising sea temperatures as an effect of climate change.ResultsHere, we used X-ray micro-computed tomography combined with 3D reconstruction to describe organogenesis in brachyuran larvae. We provide a detailed atlas of the larval internal organization to complement existing descriptions of its external morphology. In a multimethodological approach, we also used cuticular autofluorescence and classical histology to analyse the anatomy of selected organ systems.ConclusionsMuch of our fascination for the anatomy of brachyuran larvae stems from the opportunity to observe a complex organism on a single microscopic slide and the realization that the entire decapod crustacean bauplan unfolds from organ anlagen compressed into a miniature organism in the sub-millimetre range. The combination of imaging techniques used in the present study provides novel insights into the bewildering diversity of organ systems that brachyuran larvae possess. Our analysis may serve as a basis for future studies bridging the fields of evolutionary developmental biology and ecological developmental biology.

Lilliput effect in a retroplumid crab (Crustacea: Decapoda) across the K/Pg boundary

The genus Costacopluma (Brachyura: Decapoda: Retroplumidae) had a wide distribution during the early Paleogene and is currently represented by 14 species across the Late Cretaceous and early Paleogene. Described early Paleogene species have a smaller mean body size compared to Campanian-Maastrichtian populations of Africa, northeastern Mexico, and southeastern United States. Originally described from the Paleocene and Eocene of Alabama, Costacopluma grayi Feldmann and Portell, 2007, is now documented from the uppermost Maastrichtian (66.2 Ma) of northeastern Mexico and Mississippi and Lower Paleocene of Arkansas, all representing medium size specimens. The morphological features of latest Maastrichtian (66.2 Ma) individuals are identical to those observed among populations of C. grayi from the Paleogene of Alabama and Arkansas, which have a smaller mean size. This size reduction, or dwarfism, in C. grayi across the K-Pg boundary is an example of the Lilliput effect. Dwarfism has been documented in several invertebrate groups as a response to environmental stress, but this is the first record of the Lilliput effect in brachyuran crustaceans. The stratigraphic and geographic range for Costacopluma mexicana Vega and Perrilliat, 1989, is extended to the upper Campanian in northeastern Mexico and lower Maastrichtian in Mississippi and is suggested as a possible ancestor of C. grayi. Different preservational modes for this species in northeastern Mexico are discussed.

Feeding habits of the sea turtles Caretta caretta and Lepidochelys olivacea in south-eastern Brazil

Studies of the feeding habits of sea turtles are important in identifying their feeding grounds and preferred prey, thus helping with management decisions regarding habitat protection. The present study describes, for the first time, the feeding habits of the sea turtlesCaretta carettaandLepidochelys olivaceain Rio de Janeiro State, south-eastern Brazil (22°06′S–22°55′S). The stomach contents of fiveC. carettaand fiveL. olivacearecovered between 2009 and 2010 were analysed to identify the prey species. A common feeding pattern was noted for both species, with bottom-dwelling prey (fish, crustaceans, molluscs and echinoderms), common in shallow environments, constituting the main food items. All fish and brachyuran crustacean species identified in the stomach contents were by-catch in small-scale shrimp fisheries that operate along the study area. The coastal waters of Rio de Janeiro State represent a new feeding ground forL. olivacea, expanding its preferential habitat during the non-reproductive period. The results provide strong evidence for the likelihood that sea turtles are interacting with fisheries due to an overlapping between feeding and fishery grounds. An evaluation of carcasses washed up on beaches is needed for a better understanding of the effects on the population dynamics of sea turtles.

Diet of Procyon cancrivorus (Carnivora, Procyonidae) in restinga and estuarine environments of southern Brazil

Despite its wide range and abundance on certain habitats, the crab-eating raccoon Procyon cancrivorus (G. Cuvier, 1798) is considered one of the less known Neotropical carnivore species. In the present study we analyzed the diet of P. cancrivorus in a peat forest and in an estuarine island in southernmost Brazil. Fruits of the gerivá palm tree Syagrus romanzoffiana were the most consumed item in the peat forest, followed by insects and mollusks. Small mammals, followed by Bromelia antiacantha (Bromeliaceae) fruits and brachyuran crustaceans were the most frequent items in the estuarine island. Other items found in lower frequencies were Solanum sp., Psidium sp., Smilax sp. and Dyospiros sp. fruits, diplopods, scorpions, fishes, anuran amphibians, reptiles (black tegu lizard and snakes), birds and medium-sized mammals (white-eared opossum, armadillo and coypu). Levin’s index values (peat forest: 0.38; estuarine island: 0.45) indicate an approximation to a median position between a specialist and a well distributed diet. Pianka’s index (0.80) showed a considerable diet similarity between the two systems. Procyon cancrivorus presented a varied diet in the studied areas and may play an important role as seed disperser on coastal environments in southernmost Brazil.

Sublethal Cd-induced cellular damage and metabolic changes in the freshwater crab Sinopotamon henanense

To explore whether sublethal cadmium (Cd) exposure causes branchial cellular damages and affects the metabolic activity in brachyuran crustaceans, the freshwater crab Sinopotamon henanense was exposed to 0.71, 1.43, and 2.86 mg/L Cd(2+) for 3 weeks. Gill morphology, metabolic activity (activities of isocitrate dehydrogenase (IDH), cytochrome c oxidase (CCO) and lactate dehydrogenase (LDH), mRNA expression of CCO active subunit 1 (cco-1) and ldh, as well as ATP levels) in crab muscle were investigated. The results showed that sublethal Cd exposure caused profound morphological damages in the gills. The branchial epithelial cells were disorganized and vacuolized. Ultrastructurally, a decrease in number of apical microvilli, vacuolized mitochondria, and condensed chromatin were observed in gill epithelial cells. Correspondingly, the Cd exposure also induced downregulations of cco-1 and ldh mRNA expression and reduced activities of IDH, CCO, and LDH, in accordance with the lower ATP level in crab muscle. These results led to the conclusion that gill damage caused by sublethal Cd exposure could lead to an impairment of oxygen uptake of S. henanense, and the inhibition of metabolic activity decreases the oxygen demand of the crab and assists them to survive under the condition of lower oxygen availability. These effects add to our understanding on toxic effects of Cd and survival management of S. henanense subchronically exposed to sublethal Cd.

Brachyuran crustaceans from the bycatch of prawn fisheries at the mouth of the Amazon river

The present paper is a pioneering study on the Brachyura bycatch associated with the artisan prawn fisheries at the mouth of the Amazon River. The study was conducted at four collection sites distributed along the mouth of the Amazon River between the months of January/2009 and January/2010. The animals were caught using handcrafted traps called "matapi", which are used by prawn fisherman in the region. Twenty matapis were used at each collection site. A total of 145 specimens were captured and six species were identified, all belonging to the Trichodactylidae family - Sylviocarcinus maldonadoensis, S. pictus, S. devillei, Valdivia serrata, Dilocarcinus septemdentatus and D. pagei. The most representative species, S. maldonadoensis, S. pictus and S. devillei were classified as regular. Regarding the composition of the capture, there were three specimens of D. pagei , only one male specimen of D. septemdentatus, forty-eight specimens of S. maldonadoensis, sixty-eight specimens of S. pictus, twenty-two specimens of S. devillei and three specimens of V. serrata. In all months, the brachyuran fauna showed a considerably lower biomass when compared to the prawns, representing only 5% of the catch, in a ratio of 1:0.06. For most species, the number of males was always higher than the number of females in almost all collection months.

Local knowledge of traditional fishermen on economically important crabs (Decapoda: Brachyura) in the city of Conde, Bahia State, Northeastern Brazil

BackgroundThis article records the traditional knowledge of crab gatherers in the city of Conde, in the North Coast Region of Bahia State, Northeastern Brazil.MethodsData on biological and ecological aspects of economically important brachyuran crustaceans have been obtained from semi-structured interviews and in loco observations conducted from September 2007 to December 2009. A total of 57 fishermen of both genders, aged between 10 and 78 years have been interviewed (individually or collectively) in different contexts; interviewees were asked about aspects such as external morphology, life cycle, trophic ecology, and spatial and temporal distribution of the major economically important brachyuran crustaceans in the region. Seven fishing communities were visited: Siribinha, Sítio do Conde, Poças, Ilha das Ostras, Cobó, Buri and Sempre Viva. Data were analyzed by comparing the information provided by participants with those from the specialized academic literature.ResultsThe results show that artisanal fishermen have a wide ranging and well-grounded knowledge on the ecological and biological aspects of crustaceans. Crab gatherers of Conde know about growth and reproductive behavior of the animals they interact with, especially with regard to the three major biological aspects: “molt”, “walking dance” and “spawning”.ConclusionThis knowledge constitutes an important source of information that should be considered in studies of management and sustainable use of fishery resources in the North Coast Region of Bahia State.

Saberes pesqueiros relacionados à coleta de siris e caranguejos (Decapoda: Brachyura) no município de Conde, Estado da Bahia

O presente artigo registra os saberes pesqueiros empíricos relacionados com o extrativismo de crustáceos braquiúros de importância econômica no município de Conde, Litoral Norte do Estado da Bahia, caracterizando as técnicas e apetrechos empregados na coleta desses crustáceos, além de discutir aspectos ligados à comercialização do pescado e à territorialidade. Os dados foram obtidos no período de setembro de 2007 a dezembro de 2009 mediante entrevistas semi-estruturadas e observações comportamentais, recorrendo-se às técnicas usuais de registro etnográfico. Foram entrevistados 57 pescadores artesanais, de ambos os gêneros, com idades entre 10 e 78 anos. Os dados foram analisados qualitativamente comparando-se os saberes locais com a literatura acadêmica especializada. Foram realizadas quatro campanhas de análise biométrica de siris (Callinectes spp.) com o objetivo de determinar a proporção sexual e morfométrica. Os resultados mostram que a coleta de crustáceos tem uma motivação predominantemente econômica, embora também seja a principal fonte de subsistência local. Na análise biométrica dos indivíduos de siris foi evidenciada a preferência por animais de porte maior, independente do gênero. A pesca artesanal dos crustáceos em Conde é realizada com uma diversidade de técnicas e apetrechos que, de forma direta ou indireta, interfere na dinâmica faunística e ecossistêmica. Embora haja uma consciência conservacionista por parte dos participantes da pesquisa, evidenciam-se diferentes atitudes de manejo. Trabalhos posteriores podem vir a fornecer subsídios visando ao manejo e uso sustentável destes recursos pesqueiros, vindo a beneficiar as comunidades locais.

Physiological basis for high CO<sub>2</sub> tolerance in marine ectothermic animals: pre-adaptation through lifestyle and ontogeny?

Abstract. Future ocean acidification has the potential to adversely affect many marine organisms. A growing body of evidence suggests that many species could suffer from reduced fertilization success, decreases in larval- and adult growth rates, reduced calcification rates, and even mortality when being exposed to near-future levels (year 2100 scenarios) of ocean acidification. Little research focus is currently placed on those organisms/taxa that might be less vulnerable to the anticipated changes in ocean chemistry; this is unfortunate, as the comparison of more vulnerable to more tolerant physiotypes could provide us with those physiological traits that are crucial for ecological success in a future ocean. Here, we attempt to summarize some ontogenetic and lifestyle traits that lead to an increased tolerance towards high environmental pCO2. In general, marine ectothermic metazoans with an extensive extracellular fluid volume may be less vulnerable to future acidification as their cells are already exposed to much higher pCO2 values (0.1 to 0.4 kPa, ca. 1000 to 3900 μatm) than those of unicellular organisms and gametes, for which the ocean (0.04 kPa, ca. 400 μatm) is the extracellular space. A doubling in environmental pCO2 therefore only represents a 10% change in extracellular pCO2 in some marine teleosts. High extracellular pCO2 values are to some degree related to high metabolic rates, as diffusion gradients need to be high in order to excrete an amount of CO2 that is directly proportional to the amount of O2 consumed. In active metazoans, such as teleost fish, cephalopods and many brachyuran crustaceans, exercise induced increases in metabolic rate require an efficient ion-regulatory machinery for CO2 excretion and acid-base regulation, especially when anaerobic metabolism is involved and metabolic protons leak into the extracellular space. These ion-transport systems, which are located in highly developed gill epithelia, form the basis for efficient compensation of pH disturbances during exposure to elevated environmental pCO2. Compensation of extracellular acid-base status in turn may be important in avoiding metabolic depression. So far, maintained "performance" at higher seawater pCO2 (>0.3 to 0.6 kPa) has only been observed in adults/juveniles of active, high metabolic species with a powerful ion regulatory apparatus. However, while some of these taxa are adapted to cope with elevated pCO2 during their regular embryonic development, gametes, zygotes and early embryonic stages, which lack specialized ion-regulatory epithelia, may be the true bottleneck for ecological success – even of the more tolerant taxa. Our current understanding of which marine animal taxa will be affected adversely in their physiological and ecological fitness by projected scenarios of anthropogenic ocean acidification is quite incomplete. While a growing amount of empirical evidence from CO2 perturbation experiments suggests that several taxa might react quite sensitively to ocean acidification, others seem to be surprisingly tolerant. However, there is little mechanistic understanding on what physiological traits are responsible for the observed differential sensitivities (see reviews of Seibel and Walsh, 2003; Pörtner et al., 2004; Fabry et al., 2008; Pörtner, 2008). This leads us to the first very basic question of how to define general CO2 tolerance on the species level.

Littoral biodiversity across scales in the Seychelles, Indian Ocean

The 16 Marine Protected Areas in the Seychelles Archipelago (Western Indian Ocean) are monitored by a wide range of scientific and conservation organizations, but these mainly focus on coral or fish. We have investigated variability in littoral biodiversity (with emphasis on molluscs, anomuran and brachyuran crustaceans, echinoderms and polyclad flatworms) across four spatial scales, including the largest, and previously unsurveyed, Silhouette Marine National Park. We recorded all fauna >4 mm within 1-m2 quadrats replicated at three tidal heights across transects and sites on the central granitic islands of Mahe and Silhouette and the outer Desroches coral cay. We sampled 438 quadrats and recorded 292 species of our study taxa, but accumulation curves did not reach asymptote. Most species were rare and encountered only once, although a few key species were highly abundant. Biodiversity was dominated by gastropod molluscs, which non-metric multidimensional scaling analyses showed to be a reasonable surrogate for overall faunal patterns. Non-metric multidimensional scaling showed that the fauna of each island were quite dissimilar, and after island, site explained the most variance in our generalised linear mixed models. The two least rich sites were adjacent to the only established hotel on Desroches but we cannot establish causality due to lack of a-priori data. However major enlargening of a hotel adjacent to one site on Silhouette should enable future scrutiny of tourism influences.

Characterization of a descending pathway: activation and effects on motor patterns in the brachyuran crustacean stomatogastric nervous system

The regulation of motor patterns by higher-order neuronal centers ensures appropriate motor function and behavior, but only a few studies have characterized this regulation at the cellular level. Here, we address motor pattern regulation in the stomatogastric nervous system (STNS) of the crab Cancer pagurus. This easily accessible model system is an extension of the central nervous system and contains the motor circuits that generate the rhythmic motor patterns for ingestion (esophageal rhythm) and processing of food (gastric mill and pyloric rhythms). We have documented the actions of two identified neurons located in the brain on the STNS motor circuits. We show that these neurons provide exteroceptive chemosensory information to the motor circuits and we outline their axonal projection patterns, their firing activity and their effects on three motor patterns. Backfill stainings and activity measurements in vivo and in vitro show that two neurons located in cluster 17 of the brain project via the inferior ventricular (IV) nerve to the STNS. These IV neurons started to burst rhythmically when chemosensory stimuli were applied to the first antennae. When rhythmically activated in vitro, gastric mill rhythms were elicited or, if already active, entrained by the IV neuron activity. In addition, IV neuron stimulation excited the esophageal motor neuron and inhibited several pyloric neurons such that the timing of the IV neuron activity was imposed on all motor rhythms. The IV neurons were thus capable of synchronizing the activities of different motor circuits, which demonstrates the regulation of motor patterns by higher-order neuronal centers.

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

The Asian shore crab Hemigrapsus sanguineus is a recent invader and abundant mem- ber of rocky intertidal coastlines of the eastern USA. Understanding factors influencing the settlement and metamorphosis of its larvae is important for predict- ing colonization of the species. For many species of brachyuran crustaceans studied to date, chemical cues in the natural environment stimulate molting of megalopae, the final larval stage, to the first crab stage, whereas physical cues alone have little or no effect. However, physical structure can influence the abundance of juvenile and adult crabs. In this study, I tested whether physical/structural and chemical cues stimulate molting of H. sanguineus in the labo- ratory. Molting rates of megalopae exposed to exu- dates from adult crabs (H. sanguineus and the green crab Carcinus maenas) and different physical cues varying in structural complexity (rocks with or with- out biofilms, silt particles, nylon mesh used in aqua- culture) were monitored. Megalopae molted sooner to the first crab stage in the presence of exudates of both crab species, rocks with and without biofilms, and all nylon meshes tested regardless of the size of mesh openings. By separating the effects of chem- ical and physical cues, this study shows both to be important during settlement and metamorphosis of Asian shore crab megalopae, potentially contributing to its successful colonization of North Atlantic coast- lines.

Gonad development in females of fiddler crab Uca rapax (Crustacea, Brachyura, Ocypodidae) using macro and microscopic techniques

The morphology of the ovaries in Uca rapax (Smith, 1870) was described based on macroscopic and microscopic analysis. Females were collected in Itamambuca mangrove, Ubatuba, state of São Paulo, Brazil. In the laboratory, 18 females had their ovaries removed and prepared for histology. Each gonad developmental stage was previously determined based on external and macroscopic morphology and afterwards each stage was microscopically described. The ovaries of U. rapax showed a pronounced macroscopic differentiation in size and coloration with the maturation of the gonad, with six ovarian developmental stages: immature, rudimentary, developing, developed, advanced and spent. During the vitellogenesis, the amount of oocytes in secondary stage increases in the ovary, resulting in a change in coloration of the gonad. Oogonias, primary oocytes, secondary oocytes and follicular cells were histologically described and measured. In female’s ovaries of U. rapax the modifications observed in the oocytes during the process of gonad maturation are similar to descriptions of gonads of other females of brachyuran crustaceans. The similarities are specially found in the morphological changes in the reproductive cells, and also in the presence and arrange of follicle cells during the process of ovary maturation. When external morphological characteristics of the gonads were compared to histological descriptions, it was possible to observe modifications that characterize the process in different developmental stages throughout the ovarian cycle and, consequently, the macroscopic classification of gonad stages agree with the modifications of the reproductive cells.

Crustacean hemocyanin gene family and microarray studies of expression change during eco-physiological stress

Proteins in the arthropod hemocyanin gene family are involved in major physiological processes, including aerobic respiration, the innate immune response, and molting. Members of this family, hemocyanin, cryptocyanin, and phenoloxidase, are multisubunit molecules that assemble into hexamers and higher aggregates. The hemocyanin hexamers show species-specific subunit heterogeneity. It is hypothesized that this subunit diversity is maintained as a mechanism of selection for functional diversity under changing developmental and environmental conditions. There is good evidence for a strong relationship between subunit composition and functional diversity in the hemocyanins. We have amplified, cloned, and sequenced the complete cDNAs of the 6 hemocyanin genes, 2 cryptocyanins, and 1 phenoloxidase of Cancer magister. Alignment of the amino acid sequences provides the first opportunity to assess in 1 species of brachyuran crustacean the similarities and differences among all the hemocyanin subunits and compare them with cryptocyanin and phenoloxidase. A phylogeny of sequences of crustacean members of the arthropod hemocyanin gene family is described. Construction of a cDNA library for C. magister microarray studies is in progress. The microarrays will be queried using transcriptional profiles from crabs sampled during developmental, molting, and physiological perturbations. The combination of genomics, proteomics, and gene-by-gene analyses will help us dissect how much a gene sequence in this hemocyanin family can vary while conserving function and which aspects of preservation of shape and structural flexibility are essential for functional stability. Integrating focused gene studies with global-expression profiling can eventually lead to the identification of functional networks at the level of the gene, the multisubunit molecule, and the whole organism.