The third way: spermcast mating in sessile marine invertebrates

Marine invertebrates belonging to a broad range of taxa disperse aquatic spermatozoa to fertilize eggs that are retained rather than spawned. We outline the occurrence of this mechanism, which we refer to as spermcast mating, and identify tentative generalizations relating to it. Contrasts are drawn where appropriate with broadcast spawning of both eggs and sperm for external fertilization, and with copulation or pseudocopulation. Spermcast mating may involve the gradual accumulation of long-lived spermatozoa from dilute suspension, probably during suspension feeding, and the subsequent storage of spermatozoa by the recipient (acting female) prior to fertilization. This process may involve extensive contact between spermatozoa and recipient (maternal) tissue. Mating may be influenced by compatibility systems, and receipt of compatible allosperm may trigger female investment, giving apparent scope for sexual conflict over levels of maternal investment. External fertilization of cohesive egg masses remaining close to the acting female may appear somewhat intermediate between spermcast mating and broadcast spawning but, while it may be possible to envisage a continuum between the 2 modes, the end points are distinct, commonplace, and involve contrasting reproductive characteristics. Three variants of the typical pattern of spermcast mating are briefly discussed: the spawning of zygotes (rather than the more usual brooding of progeny), polyembryony, and the dispersal of spermatophores rather than individual spermatozo

Observations of mortality of fur seals between 1998 and 2005 in Tasmania, Australia

Because of their often close relationship with the human environment, the deaths of marine mammals are often documented, particularly if there are links to anthropogenic influences. Between 1998 and 2005 a total of 504 dead Australian Fur Seals, Arctocephalus pusillus doriferus, and New Zealand Fur Seals, Arctocephalus forsteri, were reported in Tasmanian waters. Ninety individuals (18%) were dependent unweaned pups that had been displaced from their natal colonies. Of the 209 adult or subadult seals for which the cause of death could be ascertained,anthropogenic activities were identified as being responsible for the deaths of 172 individuals (82%), with 112 (53%) associated with fish farms. Most fish farm-related deaths occurred during the winter when adult and subadult seals were away from breeding colonies and seal numbers are highest around farms. The next most common cause of death was from firearms (41 individuals - 20%). Death of adults and subadults by natural causes accounted for 37 animals, or 18% of all deaths for which the cause was identified. Excluding pups, most seals were identified as Australian (80%) or New Zealand fur seals (3%). The remainder (17%) were identified as fur seals but not to species. Males were most common (58%), with only 6% identified as females; the sex of 36% could not be determined. Of the males, 106 (26%) were adults and 98 (24%) were subadults or juveniles

Application of Remote Sensing to the Chesapeake Bay Region. Volume 2: Proceedings

A conference was held on the application of remote sensing to the Chesapeake Bay region. Copies of the papers, resource contributions, panel discussions, and reports of the working groups are presented

Application of Remote Sensing to the Chesapeake Bay Region. Volume 1: Executive summary

The proceedings are presented of a conference, jointly sponsored by the National Aeronautics and Space Administration, the U.S. Environmental Protection Agency, and the University of Maryland. The purpose of the Conference was to assemble representatives of federal and state government agencies engaged in research on the condition and evolution of the Chesapeake Bay to compose a status report, to present current activities and future plans, and to recommend a long-range future course of policies and programs

The third way: spermcast mating in sessile marine invertebrates

Marine invertebrates belonging to a broad range of taxa disperse aquatic spermatozoa to fertilize eggs that are retained rather than spawned. We outline the occurrence of this mechanism, which we refer to as spermcast mating, and identify tentative generalizations relating to it. Contrasts are drawn where appropriate with broadcast spawning of both eggs and sperm for external fertilization, and with copulation or pseudocopulation. Spermcast mating may involve the gradual accumulation of long-lived spermatozoa from dilute suspension, probably during suspension feeding, and the subsequent storage of spermatozoa by the recipient (acting female) prior to fertilization. This process may involve extensive contact between spermatozoa and recipient (maternal) tissue. Mating may be influenced by compatibility systems, and receipt of compatible allosperm may trigger female investment, giving apparent scope for sexual conflict over levels of maternal investment. External fertilization of cohesive egg masses remaining close to the acting female may appear somewhat intermediate between spermcast mating and broadcast spawning but, while it may be possible to envisage a continuum between the 2 modes, the end points are distinct, commonplace, and involve contrasting reproductive characteristics. Three variants of the typical pattern of spermcast mating are briefly discussed: the spawning of zygotes (rather than the more usual brooding of progeny), polyembryony, and the dispersal of spermatophores rather than individual spermatozo

Expression of three intelectins in sheep and response to a Th2 environment

Sheep intelectin1 and sheep intelectin3 (sITLN1 and sITLN3) were cloned and sequenced. The amino acid sequences of sITLN1 and sITLN3 shared 86% and 91% homology with the previously cloned sheep intelectin2 (sITLN2), respectively. Expression of sITLN1 and sITLN3 transcript was demonstrated in abomasum, lung, colon and gastric lymph node, terminal rectum, skin, jejunum, mesenteric lymph node, ileal peyer’s patches, brain, kidney, liver, spleen, skin, ear pinna, heart and ovary in normal sheep tissues. sITLN2 transcript expression was restricted to the abomasal mucosa in normal sheep tissues. Using a non selective chicken anti-intelectin antibody, tissue intelectin protein was demonstrated in mucus neck cells in the abomasum, mucus cells in the colon, free mucus in ileum, goblet cells in the lung, small intestinal epithelium and brush border, epidermal layer of the skin and skin sebaceous glands. The expression of the three sITLN transcripts was examined in two nematode infections in sheep known to induce a Th2 response; a Teladorsagia circumcincta challenge infection model and a Dictyocaulus filaria natural infection. The three sITLN were absent in unchallenged naïve lambs and present in the abomasal mucosa of both naïve and immune lambs following T. circumcincta challenge infection. Upregulation of sITLN2 and sITLN3 was shown in sheep lung following D. filaria natural infection. Intelectins may play an important role in the mucosal response to nematode infections in ruminants

De-Noising Signals using Wavelet Transform in Internet of Underwater Things

Internet of Underwater Things (IoUT) is an emerging field within Internet of Things (IoT) towards smart cities. IoUT has applications in monitoring underwater structures as well as marine life. This paper presents preliminary work where sensor nodes were built on Arduino Uno platform with temperature and pressure sensors with wireless capability. The sensors nodes were then tested in the Flumes of the COAST laboratory to determine the maximum depth achievable in fresh water before the signal is lost as radio frequencies are susceptible to interference under water. Further, the received signals were de-noised using Wavelet Transform, Daubechies thresholding techniques at level 5. Preliminary results suggest that at a depth of 30 cm, signal was lost, de-noising of the signal was achieved with very small errors (a mean squared error of 0.106 and 0.000446 and Peak-Sign-to-Noise Ratios of 70.18 dB and 58.83 dB for the pressure and temperature signals, respectively. Results from this study will lay the foundation to further investigations in wireless sensor networks in IoUT integrating the de-noising techniques

Expression of Integrin-αE by Mucosal Mast Cells in the Intestinal Epithelium and Its Absence in Nematode-Infected Mice Lacking the Transforming Growth Factor-β1-Activating Integrin αvβ6

Peak intestinal mucosal mast cell (MMC) recruitment coincides with expulsion of Trichinella spiralis, at a time when the majority of the MMCs are located within the epithelium in BALB/c mice. Although expression of integrin-α(E)β(7) by MMCs has not been formally demonstrated, it has been proposed as a potential mechanism to account for the predominantly intraepithelial location of MMCs during nematode infection. Co-expression of integrin-α(E)β(7) and the MMC chymase mouse mast cell protease-1, by mouse bone marrow-derived mast cells, is strictly regulated by transforming growth factor (TGF)-β(1). However, TGF-β(1) is secreted as part of a latent complex in vivo and subsequent extracellular modification is required to render it biologically active. We now show, for the first time, that intraepithelial MMCs express integrin-α(E)β(7) in Trichinella-infected BALB/c and S129 mice. In S129 mice that lack the gene for the integrin-β(6) subunit and, as consequence, do not express the epithelial integrin-α(v)β(6), integrin-α(E) expression is virtually abolished and recruitment of MMCs into the intestinal epithelium is dramatically reduced despite significant overall augmentation of the MMC population. Because a major function of integrin-α(v)β(6) is to activate latent TGF-β(1,) these findings strongly support a role for TGF-β(1) in both the recruitment and differentiation of murine MMCs during nematode infection

Using Population Mixtures to Optimize the Utility of Genomic Databases: Linkage Disequilibrium and Association Study Design in India

When performing association studies in populations that have not been the focus of large-scale investigations of haplotype variation, it is often helpful to rely on genomic databases in other populations for study design and analysis – such as in the selection of tag SNPs and in the imputation of missing genotypes. One way of improving the use of these databases is to rely on a mixture of database samples that is similar to the population of interest, rather than using the single most similar database sample. We demonstrate the effectiveness of the mixture approach in the application of African, European, and East Asian HapMap samples for tag SNP selection in populations from India, a genetically intermediate region underrepresented in genomic studies of haplotype variation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65949/1/j.1469-1809.2008.00457.x.pd

The Goblet Cell Is the Cellular Source of the Anti-Microbial Angiogenin 4 in the Large Intestine Post Trichuris muris Infection

Mouse angiogenin 4 (Ang4) has previously been described as a Paneth cell-derived antimicrobial peptide important in epithelial host defence in the small intestine. However, a source for Ang4 in the large intestine, which is devoid of Paneth cells, has not been defined.Analysis was performed on Ang4 expression in colonic tissue by qPCR and immunohistochemistry following infection with the large intestine dwelling helminth parasite Trichuris muris. This demonstrated an increase in expression of the peptide following infection of resistant BALB/c mice. Further, histological analysis of colonic tissue revealed the cellular source of this Ang4 to be goblet cells. To elucidate the mechanism of Ang4 expression immunohistochemistry and qPCR for Ang4 was performed on colonic tissue from T. muris infected mouse mutants. Experiments comparing C3H/HeN and C3H/HeJ mice, which have a natural inactivating mutation of TLR4, revealed that Ang4 expression is TLR4 independent. Subsequent experiments with IL-13 and IL-4 receptor alpha deficient mice demonstrated that goblet cell expression of Ang4 is controlled either directly or indirectly by IL-13.The cellular source of mouse Ang4 in the colon following T. muris infection is the goblet cell and expression is under the control of IL-13