Structure and function of the spermathecal complex in the phlebotomine sandfly Phlebotomus papatasi Scopoli (Diptera: Psychodidae): II. post-copulatory histophysiological changes during the gonotrophic cycle.
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The spermathecal complex of Phlebotomus papatasi Scopoli (Diptera: Psychodidae) undergoes histological and physiological changes during its gonotropic cycle. The present histochemical study revealed a mucopolysaccharide secretory mass in the spermathecae of the newly emerged sandfly. Sperm competition occurs when two or more males compete to fertilize an ovum in the female reproductive tract. In this study, spermatophores of two or more competing males were deposited at the base of the spermathecal ducts, which originate from the female bursa copulatrix. This suggests that females play a role in sperm displacement, which is defined as any situation in which the last male to mate with a female fertilizes maximum number her eggs. A blood meal ingested by the female for ovary development and egg laying stimulates the release of sperm from the spermatophore. The spermatozoa then migrate to the lumen of the spermatheca. The ultrastructure of spermatozoa comprises a head with double-layered acrosomal perforatorium, an elongate nucleus, and the axoneme with a 9 + 9 + 0 flagellar pattern. This axomene differs from the flagellate axoneme of other Psychodinae. Morphological changes, such as the casting off of the acrosomal membrane, and histological changes in the spermatophore are also described. Mating plugs that have been described previously in sandflies appear to be artefacts. Females of P. papatasi may be inseminated more than once during each gonotrophic cycle, and additional inseminations may be necessary for each cycle. The relationships between the volumes of the sperm and the spermatheca were calculated to determine sperm utilization and fecundity of P. papatasi. As the females of P. papatasi mate polyandrously, the anatomical and physiological complexity of the spermathecal complex may be related to post-copulatory sexual selection. (+info)
New rfp- and pES213-derived tools for analyzing symbiotic Vibrio fischeri reveal patterns of infection and lux expression in situ.
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Genetically altered or tagged Vibrio fischeri strains can be observed in association with their mutualistic host Euprymna scolopes, providing powerful experimental approaches for studying this symbiosis. Two limitations to such in situ analyses are the lack of suitably stable plasmids and the need for a fluorescent tag that can be used in tandem with green fluorescent protein (GFP). Vectors previously used in V. fischeri contain the p15A replication origin; however, we found that this replicon is not stable during growth in the host and is retained by fewer than 20% of symbionts within a day after infection. In contrast, derivatives of V. fischeri plasmid pES213 were retained by approximately 99% of symbionts even 3 days after infection. We therefore constructed pES213-derived shuttle vectors with a variety of selectable and visual markers. To include a visual tag that can be used in conjunction with GFP, we compared seven variants of the DsRed2 red fluorescent protein (RFP): mRFP1, tdimer2(12), DsRed.T3, DsRed.T4, DsRed.M1, DsRed.T3_S4T, and DsRed.T3(DNT). The last variant was brightest, displaying >20-fold more fluorescence than DsRed2 in V. fischeri. RFP expression did not detectably affect the fitness of V. fischeri, and cells were readily visualized in combination with GFP-expressing cells in mixed infections. Interestingly, even when inocula were dense enough that most E. scolopes hatchlings were infected by two strains, there was little mixing of the strains in the light organ crypts. We also used constitutive RFP in combination with the luxICDABEG promoter driving expression of GFP to visualize the spatial and temporal induction of this bioluminescence operon during symbiotic infection. Our results demonstrate the utility of pES213-based vectors and RFP for in situ experimental approaches in studies of the V. fischeri-E. scolopes symbiosis. (+info)
Redestribution of Chironomus salinarius (Diptera: Chironomidae), nuisance midges that emerged in brackish water of Jinhae-man (Bay), Kyongsangnam-do, Korea.
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Huge numbers of non-biting midges emerged from brackish water which were made at the harbor construction field in Jinhae City, Kyongsangnam-do, Korea in late summer in 2005, and caused a serious nuisance to villagers. The midges were collected and identified as Chironomus salinarius (Kieffer, 1921). Although this species was recorded in Korea for the first time in 1998, the morphological descriptions were so brief and simple. A full redescription is made with detailed illustrations for ecological and control workers of this nuisance midge. (+info)
Establishment and characterization of two cell lines from bluefin trevally Caranx melampygus.
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Bluefin trevally Caranx melampygus Cuvier is a popular game fish and highly valued sea food with potential importance for aquaculture. To help establish this marine animal as an important aquacultural species in Hawaii and the Pacific and develop in vitro cell culture systems for long-term management and control of potential viral diseases 2 cell lines were established from body muscle (bluefin trevally muscles, BTMS) and fins (bluefin trevally fins, BTF). Primary culture of these cells was conducted at 25 degrees C using L-15 medium supplemented with 20% fetal bovine serum and various antibiotics. These cells have been serially subcultured 37 to 41 times since their initiation in June 2002. Growth of the bluefin trevally cells was serum-dependent at the time of the experiments and their plating efficiencies ranged from 11 to 28.2%. Comparative analysis showed that these bluefin trevally cells grew equally well in the media L-15 (Leibovitz medium), RPMI 1640, M199 and MEM (minimum essential medium), which are commonly used for cell cultures derived from aquatic animals and mammalian species. Examination of the early passage cells stored at -196 degrees C revealed a large percent (nearly 98%) of cell viability following a 6 mo storage in liquid nitrogen. Karyotyping analysis indicated that these bluefin trevally derived cell lines remained diploid with a chromosome count of 48 at passage 7 and 12. These 2 cell lines shared a same pattern of viral susceptibility and they were sensitive to infectious hematopoietic necrosis virus (IHNV), infectious pancreatic necrosis (IPN), spring viremia carp virus (SVCV), viral hemorrhagic septicemia virus (VHSV), and snakehead rhabdovirus (SHRV) but refractory to channel catfish virus (CCV) infection. These newly established cell lines are currently being used to facilitate the diagnosis of viral disease affecting marine fish aquaculture in Hawaii, and will be available for future isolation and study of bluefin trevally fish viruses. (+info)
Diseases, lesions and malformations in the long-beaked common dolphin Delphinus capensis from the Southeast Pacific.
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Miscellaneous lesions of the head, skull, teeth, trunk, appendages, skin and genital tract were observed in 120 of 930 long-beaked common dolphins Delphinus capensis taken in fisheries off Peru between 1985 and 2000. Seven subsamples were defined according to the varying field sampling protocols. Forty-two dolphins showed at least 2 types of injuries or diseases affecting 1 or more organs. The majority (5 of 7) of traumas encountered were diagnosed as caused by violent, fisheries-related interactions, and the skin in 20.4 % of specimens (n = 54) showed healed scars from such interactions. Prevalences of malformations and traumas of crania (n = 103) were 2.9 and 1.9%, respectively. Lytic cranial lesions were present in 31.1% of dolphins (n = 103) and accounted for 84.2% of all bone injuries. Skull damage diagnostic for Crassicauda sp. infestation was encountered in 26.5% of dolphins (n = 98) and did not differ among sex and age classes. Crassicauda sp. and tooth infections were responsible for, respectively, 78.8 and 6.1% of the lytic lesions. Adult dolphins showed a high prevalence of worn and broken teeth (35%, n = 20) as well as damaged alveoli (20%, n = 70). Prevalence of 'paired teeth', a congenital condition, was 9.4% (n = 32). Lesions of the head, body and appendages were present in 10 dolphins and included traumas, deformations (e.g. scoliokyphosis and brachygnathia) and chronic mastitis. Ovarian cysts suggestive of follicular cysts were observed in 1 of 24 females. Chronic orchitis affected 1 of 78 males. Of 12 dolphins 2 had vesicular lesions of the penis. Prevalence of cutaneous lesions, abnormalities and scars ranged between 1.8% (n = 56) and 48.2% (n = 27). (+info)
Median fin function in bluegill sunfish Lepomis macrochirus: streamwise vortex structure during steady swimming.
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Fishes have an enormous diversity of body shapes and fin morphologies. From a hydrodynamic standpoint, the functional significance of this diversity is poorly understood, largely because the three-dimensional flow around swimming fish is almost completely unknown. Fully three-dimensional volumetric flow measurements are not currently feasible, but measurements in multiple transverse planes along the body can illuminate many of the important flow features. In this study, I analyze flow in the transverse plane at a range of positions around bluegill sunfish Lepomis macrochirus, from the trailing edges of the dorsal and anal fins to the near wake. Simultaneous particle image velocimetry and kinematic measurements were performed during swimming at 1.2 body lengths s(-1) to describe the streamwise vortex structure, to quantify the contributions of each fin to the vortex wake, and to assess the importance of three-dimensional flow effects in swimming. Sunfish produce streamwise vortices from at least eight distinct places, including both the dorsal and ventral margins of the soft dorsal and anal fins, and the tips and central notched region of the caudal fin. I propose a three-dimensional structure of the vortex wake in which these vortices from the caudal notch are elongated by the dorso-ventral cupping motion of the tail, producing a structure like a hairpin vortex in the caudal fin vortex ring. Vortices from the dorsal and anal fin persist into the wake, probably linking up with the caudal fin vortices. These dorsal and anal fin vortices do not differ significantly in circulation from the two caudal fin tip vortices. Because the circulations are equal and the length of the trailing edge of the caudal fin is approximately equal to the combined trailing edge length of the dorsal and anal fins, I argue that the two anterior median fins produce a total force that is comparable to that of the caudal fin. To provide additional detail on how different positions contribute to total force along the posterior body, the change in vortex circulation as flow passes down the body is also analyzed. The posterior half of the caudal fin and the dorsal and anal fins add vortex circulation to the flow, but circulation appears to decrease around the peduncle and anterior caudal fin. Kinematic measurements indicate that the tail is angled correctly to enhance thrust through this interaction. Finally, the degree to which the caudal fin acts like a idealized two-dimensional plate is examined: approximately 25% of the flow near the tail is accelerated up and down, rather than laterally, producing wasted momentum, a loss not present in ideal two-dimensional theories. (+info)
Coding of odors by a receptor repertoire.
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We provide a systematic analysis of how odor quality, quantity, and duration are encoded by the odorant receptor repertoire of the Drosophila antenna. We test the receptors with a panel of over 100 odors and find that strong responses are sparse, with response density dependent on chemical class. Individual receptors range along a continuum from narrowly tuned to broadly tuned. Broadly tuned receptors are most sensitive to structurally similar odorants. Strikingly, inhibitory responses are widespread among receptors. The temporal dynamics of the receptor repertoire provide a rich representation of odor quality, quantity, and duration. Receptors with similar odor sensitivity often map to widely dispersed glomeruli in the antennal lobe. We construct a multidimensional "odor space" based on the responses of each individual receptor and find that the positions of odors depend on their chemical class, concentration, and molecular complexity. The space provides a basis for predicting behavioral responses to odors. (+info)
Detection of the herpesviral hematopoietic necrosis disease agent (Cyprinid herpesvirus 2) in moribund and healthy goldfish: validation of a quantitative PCR diagnostic method.
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Cyprinid herpesvirus 2 (CyHV-2) is a pathogen of goldfish Carassius auratus auratus L. that causes herpesviral hematopoietic necrosis (HVHN) disease. The disease is associated with necrosis of hematopoietic tissues and anemia with high mortality. We have developed a real time 5'-nuclease PCR method (Taqman) that quantitatively detects CyHV-2 with a linear response over 8 logs of target concentration. The coefficient of variability on replicate samples tested on different days was 13% and the calculated sensitivity approached 1 target molecule per reaction. The assay does not cross-react with other similar fish herpesviruses, including CyHV-1 (carp pox) and CyHV-3 (koi herpesvirus), but reliably detects known CyHV-2 positive fish. The assay detects CyHV-2 not just in clinical cases of HVHN but also in apparently healthy 1 yr old goldfish fingerlings and even in 3 to 5 yr old broodfish. (+info)