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Low-latitude reefs and reef islands usually experience relatively benign climatic and hydrodynamic conditions due to their location near to the equator, outside of the major storm belts, and they typically exhibit geomorphological traits that reflect the prevailing low-energy conditions. For example, algal ridges are poorly developed, reef flat boulder zones are modest or lacking, rubble banks are rare, and reef islands tend to be low and dominated by sand. Nukutoa is a low-lying triangular-shaped reef island of ~6 ha located on the eastern rim of Takuu atoll (4°45'S, 157°2'E), Papua New Guinea, approximately 300 km northeast of Bougainville. The approximately 450 residents of Takuu all live on Nukutoa. In December 2008 Takuu was struck by several days of very high water levels and waves, which washed completely over approximately 50% of Nukutoa. GPS shoreline mapping and topographic surveys of the island were undertaken in the days immediately prior to the event, and were repeated immediately after. Homes and village infrastructure were damaged during this event, which eroded around 60% of the shoreline, and deposited a sand sheet averaging around 50 mm thick over approximately 13% of the island. This event was generated by two distant storms - one located > 6000 km away near 50°N, and affected a wide area of the Western Pacific. Oral histories record at least five similar events since the 1940s. In this paper we document the geomorphic impacts of the December 2008 event and discuss the possible significance of similar events in the past, and in the future. [ABSTRACT FROM AUTHOR]

Tropical Cyclone (TC) Yasi (Category 5) was a large (~700 km across) cyclone that crossed Australia's Queensland coast on the 3rd of February 2011. TC Yasi was one of the region's most powerful recorded cyclones, with winds gusting to 290 km/h and wave heights exceeding 7 m. Here we describe the impacts of TC Yasi on a number of nearshore, turbid-zone coral reefs, that include several in the immediate vicinity of the cyclone's landfall path (King Reef, Lugger Shoal and Dunk Island), as well as a more distally located reef (Paluma Shoals) ~150 km to the south in Halifax Bay. These reefs were the focus of recent (between 2006 and 2009) pre-Yasi studies into their geomorphology, sedimentology and community structure, and here we discuss data from a recent (August 2011) post-Yasi re-assessment. This provided a unique opportunity to identify and describe the impacts of an intense tropical cyclone on nearshore reefs, which are often assumed to be vulnerable to physical disturbance and reworking due to their poorly lithified framework. Observed impacts of TC Yasi were site specific and spatially highly heterogeneous, but appear to have been strongly influenced by the contemporary evolutionary stage and ecological make-up of the individual reefs, with site setting (i.e. exposure to prevailing wave action) apparently more important than proximity to the landfall path. The most significant ecological impacts occurred at King Reef (probably a result of freshwater bleaching) and at Paluma Shoals, where widespread physical destruction of branched Acropora occurred. New coral recruits are, however, common at all sites and colony re-growth clearly evident at King Reef. Only localised geomorphic change was evident, mainly in the form of coral fracturing, rubble deposition, and sediment movement, but again these impacts were highly site specific. The dominant impact at Paluma Shoals was localised storm ridge/shingle sheet deposition, at Lugger Shoal major offshore fine sediment flushing, and at Dunk Island major onshore coarse sand deposition. There was little geomorphic change evident at King Reef. Thus whilst small-scale and taxa specific impacts from Cyclone Yasi are clearly evident, geomorphological changes appear minor and ecological impacts highly variable between sites, and there is no observed evidence for major reef structural change. The study suggests that the vulnerability of reefs to major physical disturbance events can be extremely site specific and determined by interacting factors of location relative to storm path and pre-event geomorphology and ecology. [ABSTRACT FROM AUTHOR]

Global-scale deteriorations in coral reef health are projected to lead to a progressive decline in reef-building potential and ultimately to states of net reef erosion. These transitions may be driven by various human disturbances and by climate change; however, increased terrestrial sediment and nutrient yields from anthropogenically modified coastal catchments are widely recognized as a major threat. As water quality deteriorates, reduced coral cover and species diversity are commonly inferred, and lower reef accretion rates and impaired reef development are assumed consequences. Here we present a detailed chronostratigraphic growth history, constrained by 40 accelerator mass spectrometry radiocarbon dates for Middle Reef, an inshore turbid-zone reef on Australia's Great Barrier Reef, that challenges the assumption that high terrestrial sediment inputs inherently restrict reef accretion rates and inhibit reef development. We establish that Middle Reef has vertically accreted very rapidly for more than 700 yr, at an average rate of 8.3 mm yr-1. Accretion rates varied across the reef at different times, but it is significant that the periods of most rapid accretion (averaging 13.0 mm yr-1) coincide with phases of reef development dominated by fine-grained terrigenoclastic sediment accumulation. We suggest that this is in large part a function of a high rate of terrigenous sediment accumulation aiding the postmortem preservation of coral skeletal material. Both maximum and site-averaged accretion rates match or exceed those documented for most clear-water, mid- and outer-shelf reefs in the region over the past 9000 yr, and those determined for many reefs throughout the Indian and Pacific Oceans over the same period. While examples of inshore coral reefs that have been degraded in the short term by excessive terrestrial sedimentation clearly exist, others clearly tolerate high sedimentation and turbidity, and our data confirm that sustained and long-term rapid reef growth is possible in these environments. [ABSTRACT FROM AUTHOR]

A model that resolves reef island formation in relation to both reef platform substrate development and mid-Holocene sea-level change is presented for Bewick Island, northern Great Barrier Reef, based on morphostratigraphic analysis and radiometrically dated island sediments and reef corals. On Bewick Island, microatolls record reef-flat development at higher sea level (+1.5 m) by 6500 yr B.P. Island building began on a partially emergent reef flat 5000-4000 yr B.P., when sea level was 0.5 m above present. As sea level fell to its present level, the reef platform process window closed and the island core stabilized. Results present the first unequivocal evidence of island building directly over a reef flat comprising microatolls, and the first detailed model of island formation from the Great Barrier Reef. The model demonstrates that the interplay of sea level and reef surface elevation can vary between sites but their convergence is critical for island initiation. Future trajectories of island change will vary, dependent on the unique relative sea level and substrate depth conditions that govern island formation. [ABSTRACT FROM AUTHOR]

Radiometrically calibrated ages from three reef cores are used to develop a Holocene reef growth chronostratigraphy and sea-level history in the Maldives, central Indian Ocean. Last interglacial reef (U-series age 122 ± 7 ka) was encountered at 14.1 m below mean sea level. An age of ca. 8100 calibrated (cal) yr B.P. immediately overlying this Pleistocene surface records the initiation of Holocene reef growth. Massive in situ corals occur throughout the cores and the consistency of the three age-depth plots indicate that the reef grew steadily between 8100 and 6500 cal yr B.P., and at a decreasing rate for the next 2 k.y. The position of modern sea level was first achieved ca. 4500 cal yr B.P. and sea level reached at least 0.50 ± 1 m higher from 4000 to 2100 cal yr B.P. before falling to present level. Emergent fossil microatolls provide evidence of this higher sea level. Results are significant to two long-standing issues relating to Maldivian sealevel history. First, the ambiguity of a late Holocene high-stand has been resolved with clear evidence of its existence reported here. Second, the uncertainty of the regional pattern of sea-level change in the central Indian Ocean has been clarified, the Maldivian results broadly agreeing with island records in the eastern, rather than western Indian Ocean. Our results provide the first field evidence confirming geophysical model projections of a highstand 4-2 k.y. ago in the central Indian Ocean, though the observed level (+0.50 ± 0.1 m) is lower than that projected. [ABSTRACT FROM AUTHOR]

Increased terrestrial sediment and nutrient yields are regarded as significant threats to coral reef health. Within the central Great Barrier Reef lagoon, where water quality has reportedly declined since European settlement (since ca. A.D. 1850), inner-shelf reef conditions have purportedly deteriorated. However, the link between reef decline and water-quality change remains controversial, primarily because of a lack of pre-European period ecological baseline data against which to assess contemporary ecological states. Here we present a high-resolution record of reef accretion and coral community composition from a turbid-zone, nearshore reef on the inner shelf of the Great Barrier Reef; the record is based on six radiocarbon date-constrained cores, and extends back to ca. 1200 calibrated yr B.P. Results demonstrate not only the potential for coral communities to initiate and persist in settings dominated by fine-grained terrigenous sediment accumulation, but also that a temporally persistent (but low diversity) suite of corals has dominated the reef-building community at this site for at least the past millennium. Furthermore, the coral assemblages exhibit no evidence of community shifts attributable to post-European water-quality changes. While extrapolation of these findings to other turbid-zone reefs must remain tentative, the study raises important questions about the resilience of inner-shelf reefs that are under terrestrial sediment influence and subject to elevated turbidity conditions, and demonstrates the potential to develop detailed, millennial time scale, coral community records from Holocene reef systems. [ABSTRACT FROM AUTHOR]

Eosinophils from the peritoneal washings of normal rats adhered to live or formalin-fixed schistosomula of Schistosoma mansoni in vitro, in the presence of heat-inactivated serum from infected rats. Eosinophil adherence caused permeability changes in the schistosomula as revealed by 51Cr release and methylene blue uptake. The serum factor which mediated adherence resided in the 7S fraction after Sephadex G-200 gel filtration. Protein A from Staphylococus aurens which binds specifically to the Fc piece of IgG inhibited adherence, thereby demonstrating that IgG was the antibody responsible for this reaction and that the Fc portion was the site of interaction between eosinophil and antibody; rat eosinophils were shown to possess Fc receptors. The antibody mediating adherence reached high titres in the sera of rats 5-8 weeks after exposure to 500 cercariae, but thereafter there was a gradual decline in titre. Surface membrane from adult S. mansoni inhibited adherence, indicating, the presence of cross-reacting antigens in adult worms and schistosomula. [ABSTRACT FROM AUTHOR]

It is believed that a T-celI helper response against the schistosome surface is a necessary prerequisite for the development of protective immunity in schistosomiasis. Accordingly, the carrier effect has been used to assay eleven antigenic preparations of Schistosoma mansoni for their helper T-cell priming against surface components of the schistosomula. Three weeks after i.v. injection of the preparation, CBA mice were injected with schistosomula coated with trinitrophenol (TNP) and 4 days later, their spleens were assayed for plaque-forming cells (PEG) against TNP. Formalin-fixed schistosomula and crude adult worm tegumental membrane induced the highest response; only thirty schistosomula or 10 μg of crude membrane protein were needed to generate a T-cell helper response equivalent to that induced by a living infection. All other antigenic preparations, including formalin-fixed cercariae, live miracidia, eggs and adult worm culture fluid, generated some response indicating the presence of shared carricr components. [ABSTRACT FROM AUTHOR]

Juvenile forms of Schistosoma mansoni (schistosomula) have been cultured in human blood of various specificities and tested for the presence of blood group substances on their surfaces. The tests employed were survival following transfer into rhesus monkeys immunized against human blood substances, mixed agglutination reactions, and immunofluorescence. A, B, H and Lewisb+ antigens were expressed at the surface when the parasites were cultured in blood of appropriate specificities. Rhesus, M N S, and Duffy antigens could not be detected on the parasite surface following culture. The evidence suggests that the expressed blood group antigens are of host origin and are acquired by the parasite during culture, probably in the form of glycolipids or megalogycolipids. It is likely that these substances are also acquired by parasites in the bloodstream of man. They may serve to mask surface parasite antigens, and so enable schistosomes to evade parasitespecific humoral or cellular immune responses. [ABSTRACT FROM AUTHOR]

Faro are annular reefs, with reef flats near sea level and lagoons of variable depth, characteristic of both the perimeter and lagoons of Maldivian (Indian Ocean) atolls. Their geo- morphic development remains largely unknown, but where faro lagoons (termed velu in Maldivian) have infilled and support reef islands, these provide precious habitable land. Understanding the timing and modes of velu infilling is thus directly relevant to questions about reef island development and vulnerability. Here we use a chronostratigraphic data set obtained from a range of atoll-interior faro with partially to fully filled velu (including those with reef islands) from Baa (South Maalhosmadulu) Atoll, Maldives, to determine time scales and modes of velu infilling, and to identify the temporal and spatial thresholds that control reef island formation. Our data suggest a systematic relationship between faro size, velu infilling, and island development. These relationships likely vary between atolls as a function of atoll lagoon depth, but in Baa Atoll, our data set indicates the following faro-size relationships exist: (1) faros <~0.5 km² have velu that were completely infilled by ca. 3000 calibrated years B.P. (cal yr B.P.) with islands having established on these deposits by ca. 2.5 cal kyr B.P.; (2) faros >0.5 km² but <~1.25 km² have velu in late stages of infill, may support unvegetated sand cays and, given sufficient sand supply, may evolve into larger, more permanent islands; and (3) faros >~1.25 km² have unfilled (deeper) velu which might only infill over long time scales and which are thus unlikely to support new island initiation. These new observations, when combined with previously published data on Maldivian reef island development, suggest that while the velu of the largest faro are unlikely to fill over the next few centuries (at least), other faro with near-infilled velu may provide important foci for future reef-island building, even under present highstand (and slightly rising) sea levels. [ABSTRACT FROM AUTHOR]

The protein kinase A (PKA) is classified as type I or II depending on the association of the catalytic subunit with either the R(I) or R(II) regulatory subunits. Alterations in the levels of these regulatory subunits and PKA activity itself appear to affect cellular proliferation and tumorigenesis. We examined colorectal tumor specimens from 45 patients to investigate the potential role of cAMP-related signaling molecules in regulating tumorigenesis. Western blot analysis (PKA subunit protein levels) and in vitro kemptide phosphorylation assays (PKA catalytic subunit activity) were performed on human colorectal tumor tissue homogenates. R(I)beta protein levels were decreased 200% in ascending and 50% in descending colonic tumors compared to adjacent mucosa. R(II) protein levels were decreased 77% in descending colonic tumors but no change was observed in ascending colonic tumors compared to adjacent mucosa. PKA activity and the absolute amount of catalytic subunit protein in ascending and descending tumors were unchanged compared to adjacent mucosa. Differences in cAMP-related signaling molecules exist between neoplastic and normal colorectal tissues. These differences may not only serve as potential therapeutic targets for chemotherapeutic agents, but also lead to the identification of novel regulatory mechanisms involved in cellular proliferation and tumorigenesis.

Sm25, a major antigen in the surface tegument of the parasitic helminth Schistosoma mansoni, is a 25 kDa N-glycosylated glycoprotein which co-purifies with isolated surface membranes and behaves as an integral membrane protein in Triton X-114 (TX-114). The deduced amino acid sequence of Sm25 shows a short C-terminal hydrophobic domain between residues 163 and 180, containing six uncharged polar amino acids and followed by a Lys181-Ser192 dipeptide. We were interested in whether or not this marginal C-terminal amphiphilic domain is responsible for the association of Sm25 with the membrane or whether a post-translational modification such as the addition of glycosyl phosphatidyl inositol (GPI) represents the membrane anchor for this molecule. We find that treatment with phosphatidyl inositol-specific phospholipase C, which cleaves many GPI anchors, does not reveal Cross Reacting Determinant (CRD) on Sm25, nor affect the association of this protein with membranes, providing no support for the addition of GPI. However, Sm25 is palmitoylated via a thioester bond to the single Cys residue, at position 168, which lies within the C-terminal hydrophobic domain. Removal of palmitate by reduction results in a marked decrease in the hydrophobicity of Sm25, as demonstrated by its partitioning into the aqueous rather than detergent phase of TX-114 and its quantitative release from membrane preparations. The hydrophobicity of several membrane proteins in addition to Sm25 is also decreased by reduction, raising the possibility that fatty acylation by thioester linkage is an important mechanism used by schistosomes to stabilize protein-membrane interactions.

It is believed that a T-cell helper response against the schistosome surface is a necessary prerequisite for the development of protective immunity in schistosomiasis. Accordingly, the carrier effect has been used to assay eleven antigenic preparations of Schistosoma mansoni for their helper T-cell priming against surface components of the schistosomula. Three weeks after i.v. injection of the preparation, CBA mice were injected with schistosomula coated with trinitrophenol (TNP) and 4 days later, their spleens were assayed for plaque-forming cells (PFC) against TNP. Formalin-fixed schistosomula and crude adult worm tegumental membrane induced the highest response; only thirty schistosomula or 10mug of crude membrane protein were needed to generate a T-cell helper response equivalent to that induced by a living infection. All other antigenic preparations, including formalin-fixed cercariae, live miracidia, eggs and adult worm culture fluid, generated some response indicating the presence of shared carrier components.

Immunological reconstitution after allogeneic bone marrow transplant (BMT) was studied in 20 patients who received Campath-1 treated bone marrow. The peripheral blood lymphocyte phenotype was analysed with a panel of monoclonal antibodies at 3, 6 and 12 months. T cell proliferative capacity was evaluated by stimulation with PHA and Con A and in the mixed lymphocyte reaction (MLR). Natural killer (NK) cell activity was analysed against the K562 cell line at specified times after BMT in nine patients. Absolute numbers of T lymphocytes were reduced in all patients at 3 and 6 months. A marked decrease in the number of CD4+ cells persisted beyond 12 months. CD8+ cells regenerated more rapidly and reached normal at 6 months. No correlation was found between changes in lymphocyte subpopulations and the presence of graft-versus-host disease or cytomegalovirus infection. B cells recovered rapidly and maintained normal numbers throughout the study. A moderate increase in HNK1+ (Leu7) cells was observed at 3 and 6 months simultaneously with a low expression of NK15 (Leu11) and OKM1 antigens at 3 and 6 months, suggesting the presence of immature NK cells early after the transplant. A profound decrease of T cell proliferative capacity was observed both after mitogen stimulation and in the mixed lymphocyte reaction. NK cell activity was raised during the first month after transplant in all but one patient but no correlation was found with the presence of GVHD or cell marker analysis.

Messenger RNA has been extracted from all stages of the life cycle of the parasitic multicellular helminth Schistosoma mansoni. In vitro translation of these mRNA preparations in rabbit reticulocyte lysates yielded in each case a large number of polypeptides. Immunoprecipitation of translation products either by serum from immune mice or from human patients demonstrated that relatively few, approximately 10, polypeptides are recognised as antigens. Two of the in vitro synthesised antigens, of mol. wts. 22 000 and 14 000, were demonstrated to correspond to schistosomula surface antigens. The expression of these antigens may show stage specificity. Both are readily detected from adult and sporocyst translation products, neither from schistosomula and only the 22 000 antigen from miracidia. This is an unexpected finding since similar polypeptide antigens occur on the surface of schistosomula. These results indicate that not only are schistosomula surface antigens preformed at the preceding sporocyst stage, i.e., within the snail host, but they also remain invariant throughout the life cycle in the vertebrate host. Two other prominent schistosomula surface antigens of mol. wts. 38 000 and 32 000, were not recognised amongst cell-free translation products directed by RNA from any life cycle stage. The demonstration that at least two schistosomula surface antigens are detectable amongst adult mRNA cell-free translation products demonstrates the feasibility of identifying the genes encoding them in cDNA libraries from adult worm mRNA.