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The receptor tyrosine kinase EPHB2 has recently been identified as a TCF4 transcriptional target that controls the intestinal epithelial architecture through repulsive interactions with Ephrin-B ligands. Many reports have demonstrated that most human colorectal cancers lose EPHB2 expression despite constitutive Wnt activation. Therefore, we investigated the mechanisms that cause EPHB2 down-regulation in colorectal cancer. In this study, we demonstrate that DNA hypermethylation was not responsible for the frequent loss of EPHB2 expression in colorectal cancer. Cloning and functional characterization of the EPHB2 gene 5'-flanking region revealed a potential negative regulatory element in the distal regulatory region. In vitro electrophoretic gel mobility shift and in vivo chromatin immunoprecipitation assays demonstrated that c-Rel directly binds to the putative element. Inhibiting c-Rel activity or knocking down c-Rel expression by RNA interference in colon cancer cells was sufficient to induce EPHB2 expression. Furthermore, transient transfection assays demonstrated that c-Rel over-expression repressed endogenous EPHB2 expression in colon cancer cells. We demonstrate for the first time that c-Rel acts as a transcriptional repressor of EPHB2 and plays an active role in EPHB2 down-regulation in colorectal cancers.

Satellite-derived sea surface temperature (SST) images have had limited applications in near-shore and coastal environments due to inadequate spatial resolution, incorrect geocorrection, or cloud contamination. We have developed a practical approach to remove these errors using Advanced Very High Resolution Radiometer (AVHRR) and MODerate-resolution Imaging Spectroradiometer (MODIS) 1-km resolution data. The objective was to improve the accuracy of SST anomaly estimates in the Florida Keys and to provide the best quality (in particular, high temporal and spatial resolutions) SST data products for this region. After manual navigation of over 47 000 AVHRR images (1993-2005), we implemented a cloud-filtering technique that differs from previously published image processing methods. The filter used a 12-year climatology and plusmn3-day running SST statistics to flag cloud-contaminated pixels. Comparison with concurrent (plusmn0.5 h) data from the SEAKEYS in situ stations in the Florida Keys showed near-zero bias errors (< 0.05degC) in the weekly anomaly for SST anomalies between -3degC and 3degC, with standard deviations < 0.5degC. The cloud filter was implemented using Interactive Data Language for near-real-time processing of AVHRR and MODIS data. The improved SST products were used to detect SST anomalies and to estimate degree-heating weeks (DHWs) to assess the potential for coral reef stress. The mean and anomaly products are updated weekly, with periodic updates of the DHW products, on a Web site. The SST data at specific geographical locations were also automatically ingested in near real time into National Oceanic and Atmospheric Administration's (NOAA) Integrated Coral Observing Network Web-based application to assist in management and decision making through a novel expert system tool (G2) implemented at NOAA.

A high activity creatine amidinohydrolase (creatinase) from Arthrobacter nicotianae 02181 (a strain newly isolated from soil which may utilize creatinine as the unique organic source) was purified, characterized and the creatinase gene was cloned and analyzed in this study. Cells were cultivated under optimized condition for enzyme yield and creatinase was purified by the DEAE-cellulose and hydroxylapatite (HA) chromatography. The creatinase was found to be a dimmer formed by two identical subunit of 46.4 kDa, and the specific activity of the purified creatinase reached 124.44 U/mg protein, which was about 13 folds of the maximum value ever reported. The enzyme was found to be most active at 37 °C (pH 7.0), and it was found to be relatively stable bellow 45 °C around pH 7.0 by fluorescence spectroscopy and circular dichroism (CD) analysis. The activity of this creatinase could be significantly inhibited by Cu2+, Hg2+, Fe3+and SDS, and it could be improved by Ca2+ and NaN3.The creatinase gene was cloned by the consensus-degenerate hybrid oligonucleotide primers (CODEHOP) PCR and the genome walking method. Nucleotide sequence analysis of this gene revealed an open reading frame (ORF) of 1254 base pair (bp) encoding a 417 amino acid (aa) protein. The primary amino acid sequence alignment search in the database revealed a moderate homology between the deduced amino acid sequence and other creatinase. The sequence has been submitted to Genbank with the accession number EU004199 .

Ocean color images acquired from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) from 1998 to 2006 were used to examine the patterns of physical connectivity between land and reefs, and among reefs in the Mesoamerican Barrier Reef System (MBRS) in the northwestern Caribbean Sea. Connectivity was inferred by tracking surface water features in weekly climatologies and a time series of weekly mean chlorophyll-a concentrations derived from satellite imagery. Frequency of spatial connections between 17 pre-defined, geomorphological domains that include the major reefs in the MBRS and river deltas in Honduras and Nicaragua were recorded and tabulated as percentage of connections. The 9-year time series of 466 weekly mean images portrays clearly the seasonal patterns of connectivity, including river plumes and transitions in the aftermath of perturbations such as hurricanes. River plumes extended offshore from the Honduras coast to the Bay Islands (Utila, Cayo Cochinos, Guanaja, and Roatan) in 70% of the weekly mean images. Belizean reefs, especially those in the southern section of the barrier reef and Glovers Atoll, were also affected by riverine discharges in every one of the 9 years. Glovers Atoll was exposed to river plumes originating in Honduras 104/466 times (22%) during this period. Plumes from eastern Honduras went as far as Banco Chinchorro and Cozumel in Mexico. Chinchorro appeared to be more frequently connected to Turneffe Atoll and Honduran rivers than with Glovers and Lighthouse Atolls, despite their geographic proximity. This new satellite data analysis provides long-term, quantitative assessments of the main pathways of connectivity in the region. The percentage of connections can be used to validate predictions made using other approaches such as numerical modeling, and provides valuable information to ecosystem-based management in coral reef provinces.

Biweekly composite averages of the standing stock of sea-surface chlorophyll (SSC) were derived from SeaWiFS satellite ocean-color data at 44 benthic sampling stations occupied along the continental slope and rise by the Deep Gulf of Mexico Benthos (DGoMB) program. At the 22 DGoMB sites north of 26°N and west of 91°W in the NW Gulf of Mexico, annual average SSC was 0.19 mg m −3 , ranging at most locations from annual highs of about 0.3 mg m −3 in November–February to lows of about 0.1 mg m −3 in May–August. Comparison of three years of SeaWiFS data (January 1998–December 2000) showed little inter-annual variation at these NW Gulf stations. In contrast, at the 22 NE Gulf sites north of 26°N and east of 91°W, SSC averaged 2.8 times higher than in the NW Gulf, showing also strong inter-annual variation. Maxima in the NE region occurred in November–February and also during summers. The summer maxima were associated with Mississippi River water transported offshore to the east and southward by anticyclonic eddies in the NE Gulf. The apparent increases in SSC in June–August at NE Gulf stations reached average monthly concentrations >50% greater than in November–February. Based on a primary productivity model and a vertical flux model, the calculated export of particulate organic carbon (POC flux reaching the seafloor) was estimated as ∼18 mg C m −2 day −1 at the 22 NE Gulf stations, and ∼9 mg C m −2 day −1 at the 22 NW Gulf stations. These estimates are comparable to fluxes measured by benthic lander by others in the DGoMB program, which may drive the differences in west versus east bathymetric zonation and community structure of macrobenthos that were sampled with large box corers by others in the DGoMB program.

The loss of coral reef habitats has been witnessed at a global scale including in the Florida Keys and the Caribbean. In addition to field surveys that can be spatially limited, remote sensing can provide a synoptic view of the changes occurring on coral reef habitats. Here, we utilize an 18-year time series of Landsat 5/TM and 7/ETM+ images to assess changes in eight coral reef sites in the Florida Keys National Marine Sanctuary, namely Carysfort Reef, Grecian Rocks, Molasses Reef, Conch Reef, Sombrero Reef, Looe Key Reef, Western Sambo and Sand Key Reef. Twenty-eight Landsat images (1984–2002) were used, with imagery gathered every 2 years during spring, and every 6 years during fall. The image dataset was georectified, calibrated to remote sensing reflectance and corrected for atmospheric and water-column effects. A Mahalanobis distance classification was trained for four habitat classes (‘coral’, ‘sand’, ‘bare hardbottom’ and ‘covered hardbottom’) using in situ ground-truthing data collected in 2003–2004 and using the spectral statistics from a 2002 image. The red band was considered useful only for benthic habitats in depths less than 6 m. Overall mean coral habitat loss for all sites classified by Landsat was 61% (3.4%/year), from a percentage habitat cover of 19% (1984) down to 7.6% (2002). The classification results for the eight different sites were critically reviewed. A detailed pixel by pixel examination of the spatial patterns across time suggests that the results range from ecologically plausible to unreliable due to spatial inconsistencies and/or improbable ecological successions. In situ monitoring data acquired by the Coral Reef Evaluation and Monitoring Project (CREMP) for the eight reef sites between 1996 and 2002 showed a loss in coral cover of 52% (8.7%/year), whereas the Landsat-derived coral habitat areas decreased by 37% (6.2%/year). A direct trend comparison between the entire CREMP percent coral cover data set (1996–2004) and the entire Landsat-derived coral habitat areas showed no significant difference between the two time series (ANCOVA; F-test, p = 0.303, n = 32), despite the different scales of measurements.

SeaWiFS chlorophyll a distributions between 1997 and 2004 were investigated in relation to sea-ice dynamics for waters west of the Antarctic Peninsula (55–75°S, 50–80°W) in order to better understand the reproductive patterns and recruitment success of the Antarctic krill, Euphausia superba . Climatology patterns showed that the Bellingshausen Sea and Marguerite Bay region usually had higher chlorophyll a concentrations, which persisted throughout austral spring and summer, compared with more northern regions along the Antarctic Peninsula and the western Scotia Sea. These predictable and long-lasting phytoplankton accumulations could provide krill with the food levels required for successful reproduction and larval survival. Unusually high krill reproduction in 2000/2001 was coincident with above-average chlorophyll a concentrations throughout most of the study area and resulted in the largest juvenile recruitment (in 2001/2002) since 1981. High larval densities (up to 132 ind m −3 ) at the shelf break along the Antarctic Peninsula may have resulted, in part, from krill spawning in the Bellingshausen Sea. In general, ice-edge blooms were only a significant feature in the southern sectors of our study area, particularly in the Bellingshausen Sea and, thus, may not support krill reproduction in the northern Peninsula region as previously believed. Instead, phytoplankton blooms during spring in the northern region appeared to be governed by shelf-break processes, such as upwelling of iron-rich deep water. Interannual differences in sea ice also probably contributed to the variability in larval krill abundances observed in Marguerite Bay. Sea ice melted early in 2000/2001, allowing elevated phytoplankton blooms to develop. In contrast, sea ice persisted throughout spring and summer 2001/2002 limiting phytoplankton accumulation, particularly in southern Marguerite Bay. Thus, the early and extended availability of elevated chlorophyll a concentrations during spring and summer 2000/2001, particularly in the vicinity of Marguerite Bay and to the south in the Bellingshausen Sea, as well as reduced sea ice in coastal areas, likely supported the unusually high densities of larval krill observed during fall in waters west of the Antarctic Peninsula.

In situ surveys (1997–2002) of Karenia brevis distribution on the west Florida shelf were used to explain spectral remote sensing reflectance, chlorophyll- a concentration, and backscattering coefficient estimates derived using SeaWiFS satellite data. Two existing approaches were tested in an attempt to differentiate K. brevis blooms from other blooms or plumes. A chlorophyll-anomaly method used operationally by the National Oceanic and Atmospheric Administration (NOAA) sometimes correctly identified K. brevis blooms but also generated false positives and false negatives. The method identified approximately 1000 km 2 of high chlorophyll-anomalies (>1 mg m −3 ) off southwest Florida between the 10 and 50-m isobaths nearly every day from summer to late fall. Whether these patches were K. brevis blooms or not is unknown. A second method used a backscattering:chlorophyll- a ratio to identify K. brevis patches. This method separated K. brevis from other blooms using in situ optical data, but it yielded less satisfactory results with SeaWiFS data. Spectral reflectance ( R rs ) estimates for K. brevis blooms, diatom blooms, and coastal river plumes are statistically similar for many cases. Large pixel size, shallow water, and imperfect algorithms distort satellite retrievals of bio-optical parameters in patchy blooms. At present, a combination of chlorophyll- a , chlorophyll-anomaly, backscattering:chlorophyll- a ratio, RGB composites, MODIS fluorescence data, as well as time-series analysis and ancillary data such as winds, currents, and sea surface temperature can improve K. brevis bloom assessments. Progress in atmospheric correction and bio-optical inversion algorithms is required to help improve capabilities to monitor K. brevis blooms from space. Further, satellite sensors with improved radiometric capabilities and temporal/spatial resolutions are also required.

We examined the spatial and temporal variability of the Secchi Disk Depth (SDD) within Tampa Bay, Florida, using the Sea-viewing Wide Field-of-View Sensor (SeaWiFS) satellite imagery collected from September 1997 to December 2005. SDD was computed using a two-step process, first estimating the diffuse light attenuation coefficient at 490 nm, K d (490), using a semi-analytical algorithm and then SDD using an empirical relationship with K d (490). The empirical SDD algorithm (SDD = 1.04 × K d (490) − 0.82 , 0.9 r 2 = 0.67, n = 80) is based on historical SDD observations collected by the Environmental Protection Commission of Hillsborough County (EPCHC) in Tampa Bay. SeaWiFS derived SDD showed distinctive seasonal variability, attributed primarily to chlorophyll concentrations and color in the rainy season and to turbidity in the dry season, which are in turn controlled by river runoff and winds or wind-induced sediment resuspension, respectively. The Bay also experienced strong interannual variability, mainly related to river runoff variability. As compared to in situ single measurements, the SeaWiFS data provide improved estimates of the “mean” water clarity conditions in this estuary because of the robust, frequent, and synoptic coverage. Therefore we recommend incorporation of this technique for routine monitoring of water quality in coastal and large estuarine waters like Tampa Bay.

We developed an approach to map turbidity in estuaries using a time series (May 2003 to April 2006) of 250-m resolution images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite, using Tampa Bay as a case study. Cross-calibration of the MODIS 250-m data (originally designed for land use) with the well-calibrated MODIS 1-km ocean data showed that the pre-launch radiometric calibration of the 250-m bands was adequate. A simple single scattering atmospheric correction provided reliable retrievals of remote sensing reflectance at 645 nm (0.002

Traditional field techniques to monitor water quality in large estuaries, such as boat-based surveys and autonomous moored sensors, generally provide limited spatial coverage. Satellite imagery potentially can be used to address both of these limitations. Here, we show that satellite-based observations are useful for inferring total-suspended-solids (TSS) concentrations in estuarine areas. A spectra-matching optimization algorithm was used to estimate the particle backscattering coefficient at 400 nm, b bp (400), in Chesapeake Bay from Sea-viewing Wide-Field-of-view Sensor (SeaWiFS) satellite imagery. These estimated values of b bp (400) were compared to in situ measurements of TSS for the study period of September 1997–December 2003. Contemporaneous SeaWiFS b bp (400) values and TSS concentrations were positively correlated ( N = 340, r 2 = 0.4, P b bp (400) values served as a reasonable first-order approximation for synoptically mapping TSS. Overall, large-scale patterns of SeaWiFS b bp (400) appeared to be consistent with expectations based on field observations and historical reports of TSS. Monthly averages indicated that SeaWiFS b bp (400) was typically largest in winter (>0.049 m −1 , November–February) and smallest in summer ( −1 , June–August), regardless of the amount of riverine discharge to the bay. The study period also included Hurricanes Floyd and Isabel, which caused large-scale turbidity events and changes in the water quality of the bay. These results demonstrate that this technique can provide frequent synoptic assessments of suspended solids concentrations in Chesapeake Bay and other coastal regions.

A wetting and drying (WAD) algorithm is implemented in a baroclinic three-dimensional ocean circu- lation model of Cook Inlet, Alaska, where large tidal ranges (≈10 m) regularly expose extensive mudflats. The model includes tides and wind- and buoyancy-induced flows. In the upper Inlet, the model successfully simulates large amplification of tides and propagation of fast (3∼ 4ms −1 ) tidal bores over shallow mudflats. The simulated return flows during ebb expose large areas (∼100 km 2 )o f the mudflats. Medium-resolution (250- and 500-m) images obtained from the moderate resolution imaging spectro- radiometer(MODIS) instrumentsaboardthe Terraand Aqua satelliteswereused toverify the modelresults byidentifying the location, extent, and temporal changes of the exposed mudflat regions. The results demonstrate the value of operational, medium-resolution remote sensing data in evaluating the WAD model. Sensitivity tests show that WAD produces approximately 20% larger tidal amplitude and 10% slower phase than the corresponding experiment without WAD. In the deep channel of the central Inlet, the confluence of saline water of the lower Inlet with brackish water from rivers and melting ice from land around the upper Inlet produces a salinity front. At the simulated front, strong vertical circulation cells and surface convergence and currents develop, especially during the flood. The char- acteristics resemble those of "rip tides" often observed in this region.

Absorption and fluorescence of colored dissolved organic matter (CDOM) and concentrations of dissolved organic carbon (DOC), chlorophyll and total suspended solids in Tampa Bay and its adjacent rivers were examined in June and October of 2004. Except in Old Tampa Bay (OTB), the spatial distribution of CDOM showed a conservative relationship with salinity in June, 2004 (aCDOM(400)= −0.19×salinity+6.78, R 2 =0.98, n=17, salinity range=1.1–32.5) with little variations in absorption spectral slope and fluorescence efficiency. This indicates that CDOM distribution was dominated by mixing. In October, 2004, CDOM distribution was nonconservative with an average absorption coefficient (aCDOM(400), ∼7.76 m −1 ) about seven times higher than that in June (∼1.11 m −1 ). The nonconservative behavior was caused largely by CDOM removal at intermediate salinities (e.g., aCDOM(400) removal N15% at salinity ∼13.0), which likely resulted from photobleaching due to stronger stratification. The spatial and seasonal distributions of CDOM in Tampa Bay showed that the two largest rivers, the Alafia River (AR) and Hillsborough River (HR) were dominant CDOM sources to most of the bay. In OTB, however, CDOM showed distinctive differences: lower absorption coefficient, higher absorption spectral slopes, and lower ratios of CDOM absorption to DOC and higher fluorescence efficiency. These differences may have stemmed from (1) changes in CDOM composition by more intensive photobleaching due to the longer residence time of water mass in OTB; (2) other sources of CDOM than the HR/AR inputs, such as local creeks, streams, groundwater, and/or bottom re-suspension. Average CDOM absorption in Tampa Bay at 443 nm, aCDOM(443), was about five times higher in June and about ten times higher in October than phytoplankton pigment absorption, aph(443), indicating that blue light attenuation in the water column was dominated by CDOM rather than by phytoplankton absorption throughout the year. © 2007 Elsevier B.V. All rights reserved.

International audience; There is currently no clinically effective vaccine against leishmaniasis because of poor understanding of the antigens that elicit dominant T cell immunity. Using proteomics and cellular immunology, we identified a dominant naturally processed peptide (PEPCK335-351) derived from Leishmania glycosomal phosphoenolpyruvate carboxykinase (PEPCK). PEPCK was conserved in all pathogenic Leishmania, expressed in glycosomes of promastigotes and amastigotes, and elicited strong CD4(+) T cell responses in infected mice and humans. I-A(b)-PEPCK335-351 tetramer identified protective Leishmania-specific CD4(+) T cells at a clonal level, which comprised similar to 20% of all Leishmania-reactive CD4(+) T cells at the peak of infection. PEPCK335-351-specific CD4(+) T cells were oligoclonal in their T cell receptor usage, produced polyfunctional cytokines (interleukin-2, interferon-gamma and tumor necrosis factor), and underwent expansion, effector activities, contraction, and stable maintenance after lesion resolution. Vaccination with PEPCK peptide, DNA expressing full-length PEPCK, or rPEPCK induced strong durable cross-species protection in both resistant and susceptible mice. The effectiveness and durability of protection in vaccinated mice support the development of a broadly cross-species protective vaccine against different forms of leishmaniasis by targeting PEPCK.

Since 2008, the world's largest blooms of the green macroalgae, Ulva prolifera, have occurred every summer in the Yellow Sea, posing the question of whether these macroalgal blooms (MABs) have changed the phytoplankton biomass due to their perturbations of nutrient dynamics. We have attempted to address this question using long-term Moderate Resolution Imaging Spectroradiometer (MODIS) observations. A new MODIS monthly time-series of chlorophyll-a concentrations (Chl-a, an index of phytoplankton biomass) was generated after removing the macroalgae-contaminated pixels that were characterized by unexpectedly high values in the daily Chl-a products. Compared with Chl-a during July of 2002-2006 (the pre-MAB period), Chl-a during July of 2008-2012 (the MAB period) exhibited significant increases in the offshore Yellow Sea waters (rich in macroalgae), with mean Chl-a increased by 98% from 0.64 mu g/L to 1.26 mu g/L in the study region. In contrast, no significant Chl-a changes were observed during June between the two periods. After analyzing sea surface temperature, photosynthetically available radiation, and nutrient availability, we speculate that the observed Chl-a changes are due to nutrient competition between macroalgae and phytoplankton: during the MAB period, the fast-growing macroalgae would uptake the increased nutrients from the origin of Jiangsu Shoal; thus, the nutrients available to phytoplankton were reduced, leading to no apparent increases in biomass in the offshore Yellow Sea in June.

Using fine spatial resolution (~7.6m) hyperspectral AVIRIS data collected over the Deepwater Horizon oil spill in the Gulf of Mexico, we statistically estimated slick lengths, widths and length/width ratios to characterize oil slick morphology for different thickness classes. For all AVIRIS-detected oil slicks (N=52,100 continuous features) binned into four thickness classes (≤50 μm but thicker than sheen, 50-200 μm, 200-1000 μm, and >1000 μm), the median lengths, widths, and length/width ratios of these classes ranged between 22 and 38 m, 7-11 m, and 2.5-3.3, respectively. The AVIRIS data were further aggregated to 30-m (Landsat resolution) and 300-m (MERIS resolution) spatial bins to determine the fractional oil coverage in each bin. Overall, if 50% fractional pixel coverage were to be required to detect oil with thickness greater than sheen for most oil containing pixels, a 30-m resolution sensor would be needed.

Using remote sensing reflectance (R(rs)(λ), sr(-1)) and phycocyanin (PC, mg m(-3)) pigment data as well as other bio-optical data collected from two cruises in September and December 2009 in Lake Dianchi (a typical plateau lake of China), we developed a practical approach to estimate PC concentrations that could be applied directly to Landsat measurements. The visible and near-IR bands as well as their band ratios of simulated Landsat data were used as inputs to the algorithms, where the algorithm coefficients for each Landsat sensor were determined through multivariate regressions. The coefficients of determination (R(2)) between the R(rs)-modeled and measured PC were all0.97 for the spectral bands corresponding to Landsat 8 OLI, Landsat 7 ETM + , Landsat 5 TM, and Landsat 4 TM, with mean absolute percentage errors (MAPE)10% for PC ranging between ~80 and 700 mg m(-3) (n = 14). The algorithms were further evaluated using an independent data set (n = 14), yielding larger but still acceptable MAPE (~30%) for PC ranging between ~80 and 500 mg m(-3). Application of the approach to Landsat 8 measurements over Lake Dianchi suggests potential use of the approach for periodical assessment of the lake's bloom conditions, yet its empirical nature together with the lack of specific narrow bands on Landsat sensors to explicitly account for the PC absorption around 625 nm calls for extra caution when applied to other eutrophic lakes.

We present satellite imagery that is interpreted as showing extensive lines of floating Sargassum in the western Gulf of Mexico in the summer of 2005. In spite of frequent reports of floating weed covering extended areas in different parts of the world's ocean, this appears to be the first observation of Sargassum from space. Satellite observations were made with the Medium Resolution Imaging Spectrometer (MERIS) on the Envisat satellite launched by the European Space Agency, and subsequently with the Moderate Resolution Imaging Spectroradiometer (MODIS) launched on both the Terra and Aqua satellites by the National Aeronautics and Space Administration. Both instruments cover wide swaths, providing near-daily images. Both have optical spectral bands in the range 670 to 750 nm, which detect the chlorophyll red-edge characteristic of land and marine vegetation, but only MERIS has a band at 709 nm, which was critical to the initial discovery. The combined satellite data from both sensors show the seasonal cycle of weed density in different areas of the Gulf. A wider ranging study is now needed to map its occurrence in other areas, including the Sargasso Sea (named for the weed, but not so far covered in our survey). The satellite observations suggest that Sargassum biomass is greater than previously estimated, and hence plays a more important part in oceanic productivity

Surface chlorophyll a concentrations (Ca ,m g m −3 ) in the Southern Ocean estimated from SeaWiFS satellite data have been reported in the literature to be significantly lower than those measured from in situ water samples using fluorometric methods. However, we found that highresolution (∼ 1k m 2 /pixel) daily SeaWiFS Ca (Ca ) data (SeaDAS4.8, OC4v4 algorithm) was an accurate measure of in situ Ca during January– February of 1998–2002 if concurrent in situ data measured by HPLC (Ca ) instead of fluorometric (Ca ) measurements were used as ground truth. Our analyses indicate that Ca is 2.48±2.23 (n=647) times greater than Ca between 0.05 and 1.5 mg m −3 and that the percentage overestimation of in situ Ca by fluorometric measurements increases with decreasing concentrations. The ratio of Ca /Ca is 1.12±0.91 (n=96), whereas the ratio of Ca /Ca is 0.55±0.63 (n=307). Furthermore, there is no significant bias in Ca (12% and −0.07 in linear and log-transformed Ca, respectively) when Ca is used as ground truth instead of Ca . The high Ca /Ca ratio may be attributed to the relatively low concentrations of chlorophyll b (Cb/Ca=0.023±0.034, n=482) and relatively high concentrations of chlorophyll c (Cc/Ca=0.25± 0.59, n=482) in the phytoplankton pigment composition when compared to values from other regions. Because more than 90% of the waters in the study area, as well as in the entire Southern Ocean (south of 60° S), have Ca between 0.05 and 1.5 mg m −3 , we consider that the SeaWiFS performance of Ca retrieval is satisfactory and for this Ca range there is no need to further develop a “regional” bio-optical algorithm to account for the previous SeaWiFS “underestimation”.

Chlorophyll-a (Chl) concentration in the Taiwan Strait (TWS) and in the South China Sea (SCS) was estimated using time series of satellite data collected with the MODIS/Aqua and SeaWiFS instruments, and validated with in situ measurements from three cruises conducted in winter and summer 2004. For Chl between 0.1 and 10 mg m− 3, both SeaWiFS and MODIS agreed well with in situ data. Errors for turbid coastal waters were larger than for offshore waters but the overall RMS (root mean square) error in log scale was within 0.35. The percentage RMS error was much larger, varying between 60% and 170% for open ocean and most of the shallow (

Daily high-resolution Sea-viewing Wide Field-of-view Sensor (SeaWiFS) images of the central North Atlantic Ocean (1998-2003) show that temporal changes in the absorption coefficient of colored dissolved organic matter (CDOM) or "yellow substance" follow changes in phytoplankton pigment absorption coefficient in time. CDOM peaks (between January and March) and troughs (late summer and fall) followed pigment peaks and troughs by approximately two and four weeks, respectively. This phase shift is additional strong evidence that CDOM in the marine environment is derived from phytoplankton degradation. The common assumption of linear covariation between chlorophyll and CDOM is a simplification even in this ocean gyre. Due to the temporal changes in CDOM, chlorophyll concentration estimated based on traditional remote sensing band-ratio algorithms may be overestimated by about 10% during the spring bloom and underestimated by a similar 10% during the fall. These observations are only possible through use of synoptic, precise, accurate, and frequent measurements afforded by space-based sensors because in situ technologies cannot provide the required sensitivity or synoptic coverage to observe these natural phenomena.

“Case-1” has been a term frequently used to characterize water type since the seventies. However, the distribution of Case-1 waters in global scale has been vague, though open ocean waters are often referred to as Case-1 in the literature. In this study, based on recent bio-optical models for Case-1 waters, an inclusive and quantitative Case-1 criterion for remote sensing applications is developed. The criterion allows Case-1 waters to have about two-fold variations of non-pigment absorption and particle backscattering around their exact Case-1 values, allowing a large range of waters to be classified as Case-1. Even so, application of this criterion to ocean color data from the SeaWiFS satellite sensor suggests that Case-1 waters occupy only about 60% of the global ocean surface. Regionally, more Case-1 waters are found in the southern hemisphere than in the northern hemisphere, and most Indian Ocean waters are found to be Case-1. The Case-1 percentage and spatial distribution change with season, and with the boundaries chosen in the criterion. Nevertheless, this study for the first time provides a quantitative and geographical perspective of Case-1 waters in global scale, and further demonstrates that many open ocean waters are not necessarily Case-1.

The Pearl River is a complex river network under the influence of heavy urbanization and industrialization. The Pearl River Estuary receives freshwater from eight major sources, each containing various pollutants. The spectral absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) in the Pearl River Estuary were studied during November 2002, a low flow (dry) season. Over a salinity range of 33–0, CDOM absorption coefficients at 355 nm (a(355)) ranged from 0.24 to 1.93 m � 1 , lower than several other American and European estuaries. In contrast to the wet season, conservative mixing was evidenced by a linear, inverse relationship between a(355) and salinity. CDOM, primarily of terrestrial origin, contained more anthropogenic organic matter than natural plant decay matter: tryptophan-like fluorophore T had the strongest signal among all fluorophores for the entire study region. The absorption spectral slope (S), determined between 300 and 500 nm, ranged between 0.0138 and 0.0184 nm � 1 and did not show distinguishable patterns except in the transition zone between the estuary and the South China Sea. The relative composition of fluorophores was found to vary among different sources. This result demonstrated the potential for using fluorophores to characterize the composition of CDOM and trace pollutants to their various freshwater sources. D 2005 Elsevier B.V. All rights reserved.

Near real-time data from the MODIS satellite sensor was used to detect and trace a harmful algal bloom (HAB), or red tide, in SW Florida coastal waters from October to December 2004. MODIS fluorescence line height (FLH in W m− 2 μm− 1 sr− 1) data showed the highest correlation with near-concurrent in situ chlorophyll-a concentration (Chl in mg m− 3). For Chl ranging between 0.4 to 4 mg m− 3 the ratio between MODIS FLH and in situ Chl is about 0.1 W m− 2 μm− 1 sr− 1 per mg m− 3 chlorophyll (Chl = 1.255 (FLH × 10)0.86, r = 0.92, n = 77). In contrast, the band-ratio chlorophyll product of either MODIS or SeaWiFS in this complex coastal environment provided false information. Errors in the satellite Chl data can be both negative and positive (3–15 times higher than in situ Chl) and these data are often inconsistent either spatially or temporally, due to interferences of other water constituents. The red tide that formed from November to December 2004 off SW Florida was revealed by MODIS FLH imagery, and was confirmed by field sampling to contain medium (104 to 105 cells L− 1) to high (> 105 cells L− 1) concentrations of the toxic dinoflagellate Karenia brevis. The FLH imagery also showed that the bloom started in mid-October south of Charlotte Harbor, and that it developed and moved to the south and southwest in the subsequent weeks. Despite some artifacts in the data and uncertainty caused by factors such as unknown fluorescence efficiency, our results show that the MODIS FLH data provide an unprecedented tool for research and managers to study and monitor algal blooms in coastal environments.

The southeastern component of a subtle ridge feature extending over 200 km along the western ramped margin of the south Florida platform, known as Pulley Ridge, is composed largely of a non-reefal, coastal marine deposit. Modern biostromal reef growth caps southern Pulley Ridge (SPR), making it the deepest hermatypic reef known in American waters. Subsurface ridge strata are layered, lithified, and display a barrier island geomorphology. The deep-water reef community is dominated by platy scleractinian corals, leafy green algae, and coralline algae. Up to 60% live coral cover is observed in 60–75 m of water, although only 1–2% of surface light is available to the reef community. Vertical reef accumulation is thin and did not accompany initial ridge submergence during the most recent sea-level rise. The delayed onset of reef growth likely resulted from several factors influencing Gulf waters during early stages of the last deglaciation (∼14 kyr B.P.) including; cold, low-salinity waters derived from discrete meltwater pulses, high-frequency sea-level fluctuations, and the absence of modern oceanic circulation patterns. Currently, reef growth is supported by the Loop Current, the prevailing western boundary current that impinges upon the southwest Florida platform, providing warm, clear, low-nutrient waters to SPR. The rare discovery of a preserved non-reefal lowstand shoreline capped by rich hermatypic deep-reef growth on a tectonically stable continental shelf is significant for both accurate identification of late Quaternary sea-level position and in better constraining controls on the depth limits of hermatypic reefs and their capacity for adaptation to extremely low light levels.

The diffuse attenuation coefficient, K (m− 1), is a measure of the effective attenuation of light in the water column. It characterizes water clarity and is used as a proxy for water quality. Mapping of shallow water benthic habitats using optical means, including daytime visible satellite imagery, requires knowledge of K to correct for water column effects such as light absorption and scattering. Traditionally, K is derived from imagery using a priori knowledge of bottom types at different depths and specific locations, and assuming that light attenuates exponentially with depth. This technique is applied to three Landsat 7 satellite images (February, May, and July 2000) from the Florida Keys Reef Tract between Key Largo and Key West. Interpolated depth data, initially from NOAA vector chart data, with uncertainties of ±0.5 m, were draped over 30 m spatial resolution Landsat satellite imagery. K was derived for 27 sites where bright sand could be observed at depths between 3 and 20 m. The blue and green bands (Landsat bands 1 and 2 at 450–520 nm and 520–600 nm, respectively) provided K values consistent with time and location. Average K values for bands 1 and 2, respectively, were 0.029 and 0.043 m− 1 (Lower Keys), 0.050 and 0.072 m− 1 (Middle Keys), and 0.063 and 0.082 m− 1 (Upper Keys). The red band (band 3, 630–690 nm) provided more ambiguous and erroneous results with several negative K values, attributed primarily to three factors use of a simple atmospheric correction, the high absorption and rapid attenuation of red light in water, and low radiometric sensitivity of the Landsat ETM + sensor. Despite the fact that these observations were a snapshot in time, trends were observed for the Upper, Middle, and Lower Keys, possibly due to the influence of more turbid Florida Bay waters.

Using Tampa Bay, FL as an example, we explored the potential for using MODIS medium-resolution bands (250- and 500-m data at 469-, 555-, and 645-nm) for estuarine monitoring. Field surveys during 21–22 October 2003 showed that Tampa Bay has Case-II waters, in that for the salinity range of 24–32 psu, (a) chlorophyll concentration (11 to 23 mg m−3), (b) colored dissolved organic matter (CDOM) absorption coefficient at 400 nm (0.9 to 2.5 m−1), and (c) total suspended sediment concentration (TSS: 2 to 11 mg L−1) often do not co-vary. CDOM is the only constituent that showed a linear, inverse relationship with surface salinity, although the slope of the relationship changed with location within the bay. The MODIS medium-resolution bands, although designed for land use, are 4–5 times more sensitive than Landsat-7/ETM+ data and are comparable to or higher than those of CZCS. Several approaches were used to derive synoptic maps of water constituents from concurrent MODIS medium-resolution data. We found that application of various atmospheric-correction algorithms yielded no significant differences, due primarily to uncertainties in the sensor radiometric calibration and other sensor artifacts. However, where each scene could be groundtruthed, simple regressions between in situ observations of constituents and at-sensor radiances provided reasonable synoptic maps. We address the need for improvements of sensor calibration/characterization, atmospheric correction, and bio-optical algorithms to make operational and quantitative use of these medium-resolution bands.

The littoral of French Guiana is characterized by the north-westward migration of large mud banks along shore and by high suspended particulate matter concentrations (SPMC) coming from the Amazon River. A correspondence function is established between in situ optical data and SPMC measurements obtained from three coastal surveys on the Kaw River, the Mahury estuary, and the adjacent continental shelf, respectively. This function is applied to SPOTsatellite images to estimate SPMC distributions near the sea surface on five dates between 1998 and 2001. Two typical situations have been observed: the mud suspensions are generally confined near the coast by a strong north-westward coastal current, while in one case (SPOTscene of 2 July 2001) the turbid plumes, probably resulted from the wave action on the mud banks, are directed seaward. SPMC varies from more than 300 mg l � 1 adjacent to the intertidal zone to a few mg l � 1 offshore. Turbid plumes are observed downstream, with regard to the Guyana Current, of small islands along the coast. Mud undulations are observed on the emergent surface of the mudflats, parallel to the crest waves and characterized by a wavelength of 200–1000 m. These structures are interpreted to form by wave action on the soft mudflat surface. Mangrove colonization of the mudflat follows these primary topographic structures. D 2004 Elsevier B.V. All rights reserved.

In the article, we focus on the properties, sources, sinks, measurement techniques, and distribution patterns of the major dissolved component of ocean color, CDOM. Through an understanding of the complex characteristics and environmental interactions of the CDOM pool, we can gain valuable insight into a variety of physical and biogeochemical processes occurring in coastal and shelf regions.

Monthly hydrographic, phytoplankton biomass and primary production, bio-optical observations, and settling particulate organic carbon flux observations were collected at 10.5°N, 64.67°W within the Cariaco Basin, off Venezuela, for a period exceeding seven years starting in November 1995. These data were combined with a time series of Sea-viewing Wide-Field-of-view Sensor (SeaWiFS), advanced very high-resolution radiometer (AVHRR), and European Remote Sensing Satellite/QuikScat data to examine the spatial extent of a cold coastal upwelling plume and a phytoplankton bloom associated with it. The seasonal upwelling cycle was directly linked to the intensity of the Trade Winds, with sea-surface temperature (SST) changes lagging the wind by 1–2 weeks. The seasonal cycle of most properties was punctuated by transient phenomena, some of which caused subsurface ventilation and also high primary production events. Integrated primary production ranged from 650, 574, and 593 g C m−2 yr−1 in 1996, 1997, and 2001, respectively, to 372, 484, and 448 g C m−2 yr−1, respectively, in 1998, 1999, and 2000. The Rutgers vertical generalized production model (VGPM) was modified to reflect an increase in Assimilation Number (PBopt) with SST at the Cariaco time series station, because the original VGPM formulation suggested inhibition of primary production at SST>21°C. Trap observations showed that between 9 and 10 g C m−2 yr−1 were delivered to the bottom at the Cariaco time series station, i.e. ∼1.33% of surface primary productivity. Annual particulate organic carbon flux to the bottom over the area of the Cariaco Basin (waters >100 m), estimated using SeaWiFS and AVHRR variable inputs and the updated VGPM, ranged from 6.77×1010 to 7.61×1010 g C. These are likely underestimates due to lack of bathymetric corrections to flux.

In principle, a priori knowledge of organism-scale spectral signatures for key ecological end-members is a basic requirement for identifying coral reef benthic communities using hyper- spectral remotely-sensed imagery. Spectral signatures of end-members are now relatively well known for predominant reef taxa (coral, algae) and for the background of the living communities (e.g. sediments). What remains unclear is whether the criteria for spectral discrimination between end- members at the millimeter or centimeter scale remain valid when attempting to process images at several meters resolution. In other words, is it possible to scale-up spectral criteria of identification from species/organisms to communities? We address this issue with in situ and 'compact airborne spectrometer imager' (CASI) hyperspectral measurements of the tropical marine flora of 2 South Pacific Ocean coral reefs. Targets were the dominant algal species and communities encountered in the shallow (0 to 3 m) barrier and fringing reefs of Moorea Island and the outer margin of the rim of Rangiroa Atoll (French Polynesia). Stepwise wavelength selection and linear discriminant analysis highlighted the key non-redundant wavelengths necessary to achieve good separation between the predefined ecological groups. Comparison of the wavelengths identified from in situ and airborne measurements allowed definition of a subset of common wavelengths that were robust to changes in spatial scale and still provided excellent discrimination and classification accuracy between the eco- logical groups. These results suggest that continuous spectral signatures acquired in situ at the centi- meter scale can be used to select key discrete wavelengths for remote-sensing observations of com- munities at the meter scale despite the spatial heterogeneity in benthic cover and the resulting spectral mixing.

Reorganization of the actin cytoskeleton is crucial to the formation and function of the immunological synapse. Rho GTPases are critical mediators of cytoskeletal reorganization, and their activity at the synapse is likely to be stringently regulated. Guanine nucleotide exchange factors (GEFs) belonging to the Dbl family of proteins represent one major class of proteins that regulate the activity of Rho GTPases. Here we demonstrate that IBP, a homologue of SWAP-70, is a novel GEF for Rac1 and Cdc42 in T lymphocytes, which is recruited to the immunological synapse upon engagement of the antigen receptor. Mutational analysis supports a model whereby IBP is inactive in unstimulated cells. Upon engagement of the T cell receptor, its GEF activity is enhanced by tyrosine phosphorylation, as well as by binding newly generated phosphatidylinositol 3,4,5-trisphosphate. Although it is known that T cell receptor engagement leads to the recruitment of Vav to the immunological synapse, these findings indicate that other GEFs, such as IBP, also relocalize to this intercellular region. The recruitment and activation of distinct classes of GEFs may allow for precise control of Rho GTPase function at the crucial interface between T cells and antigen presenting cells.

To ensure that homeostasis of the immune system is maintained, the sensitivity of lymphocytes to Fas-mediated apoptosis is differentially regulated during their activation. The molecular mechanisms that link the activation program of lymphocytes to changes in sensitivity to Fas-mediated apoptosis have, however, not been fully characterized. In these studies, we have investigated whether Fas-mediated apoptosis can be regulated by interferon regulatory factor 4 (IRF-4), a lymphoid-restricted member of the IRF family of transcription factors. IRF-4 expression is upregulated during lymphocyte activation and IRF-4–deficient mice have defects in both lymphocyte activation and homeostasis. Here, we show that stable expression of IRF-4 in a human lymphoid cell line that normally lacks IRF-4 leads to a significantly enhanced apoptotic response on Fas receptor engagement. A systematic examination of the downstream effectors of Fas signaling in IRF-4–transfected cells demonstrates an increased activation of caspase-8, as well as an increase in Fas receptor polarization. We demonstrate that IRF-4–deficient mice display defects in activation-induced cell death, as well as superantigen-induced deletion, and that these defects are accompanied by impairments in Fas receptor polarization. These data suggest that IRF-4, by modulating the efficiency of the Fas-mediated death signal, is a novel participant in the regulation of lymphoid cell apoptosis.

Satellite remote sensing is increasingly used to map and monitor coral reefs. From 1984 to the present, Landsat-5 thematic mapper (TM) and Landsat-7 enhanced thematic mapper plus (ETM+) images provide the longest time series available for change detection analysis over coral reefs. A time series of four Landsat-5 images and one Landsat-7 image spanning 1984–2000 was analyzed to detect changes in "coral-dominated", "sand", "algae", and "substrate" benthic classes for Carysfort Reef in the Florida Keys. To properly analyze this time series, a set of corrections was undertaken, which included noise-reduction correction, atmospheric correction, and TM–ETM+ data normalization. All images were classified with a Mahalanobis distance classifier using statistics from the 1984 image to identify the four benthic classes. The results were compared with historical ground-truthing data, a combination of high-resolution aerial photography and Ikonos satellite data, and results from a temporal texture change detection an...

Production of cytokines is one of the major mechanisms employed by CD4(+) T cells to coordinate immune responses. Although the molecular mechanisms controlling T cell cytokine production have been extensively studied, the factors that endow T cells with their ability to produce unique sets of cytokines have not been fully characterized. Interferon regulatory factor (IRF)-4 is a lymphoid-restricted member of the interferon regulatory factor family of transcriptional regulators, whose deficiency leads to a profound impairment in the ability of mature CD4(+) T cells to produce cytokines. In these studies, we have investigated the mechanisms employed by IRF-4 to control cytokine synthesis. We demonstrate that stable expression of IRF-4 in Jurkat T cells not only leads to a strong enhancement in the synthesis of interleukin (IL)-2, but also enables these cells to start producing considerable amounts of IL-4, IL-10, and IL-13. Transient transfection assays indicate that IRF-4 can transactivate luciferase reporter constructs driven by either the human IL-2 or the human IL-4 promoter. A detailed analysis of the effects of IRF-4 on the IL-4 promoter reveals that IRF-4 binds to a site adjacent to a functionally important NFAT binding element and that IRF-4 cooperates with NFATc1. These studies thus support the notion that IRF-4 represents one of the lymphoid-specific components that control the ability of T lymphocytes to produce a distinctive array of cytokines.

Several important optical terms, such as “absorbance” and “absorption coefficient,” are frequently used ambiguously in the current peer-reviewed literature. Because these terms are important when deriving other quantities, such as the apparent quantum yield of photoproduction, ambiguity in the application of these concepts leads to results that are difficult or impossible to interpret correctly. Such ambiguity also hinders comparison of results between studies and ultimately harms proper parameterization of numerical models of oceanic processes, as well as the refinement of remote sensing algorithms. We review these concepts and the implications of such ambiguities. A few simple recommendations that follow conventions developed by optical oceanographers are provided to authors dealing with these concepts. In particular, the symbol a is recommended for the absorption coefficient (in Napierian form, m−1), which is also preferred over absorbance (dimensionless) when data are presented; the symbol a is not recommended for absorbance; A should be used with caution because, although it has been used widely for absorbance in photochemistry and photobiology, it has also been used for absorptance in physics and optical oceanography; the term “absorptivity” is not recommended because of conflicting definitions in the current literature; the pathlength should always be given whenever absorbance data are presented; and normalization of photoproduction rates to absorbance or absorption coefficient should be performed only on optically thin samples, unless the inner filter effects are accounted for and corrected.

A large river plume generated by anomalous precipitation and oceanic circulation associated with Hurricane Mitch was detected off Honduras in October 1998 using SeaWiFS ocean color images. This event provides the background for analyzing connectivity between coral reefs and land in the Meso-American reef system. We discuss the potential implications of such short-term events for disease propagation and nutrification, and their potential significance in evolutionary processes.

In a recent work by Gould and Arnone [Remote Sens. Environ. 61 (1997) 290] the compact airborne spectrographic imager (CASI) was used to map the absorption and scattering properties of a coastal environment. The methodology used in this work is also cited in a number of more recent studies. The authors found large discrepancies between the parameters estimated from measurements (AC9) and from a bio-optical model by Carder et al. [J. Geophys. Res. 104 (1999) 5403]. As a result, they adjusted the backscattering efficiency parameter of the model. We found, however, that the discrepancies may actually be due, at least in part, to an erroneous atmospheric correction used for the airborne data. Because the removal of the surface-reflected sky radiance was neglected, the estimated water-leaving radiance was erroneously augmented and used as the input of the bio-optical model. This caused a scattering overestimate and an absorption underestimate. It is suggested that the surface reflection, unlike for land applications, should always be removed to obtain the water signal for use with such bio-optical models.

A new empirical Chl-a algorithm has been developed and validated for the largest freshwater lake of China (Poyang Lake) using a normalized green-red difference index (NGRDI), where the uncertainty was estimated to be ~25 mg·L−1 total suspended sediments or TSS) masked. The long-term Chl-a distribution showed significant spatial gradient and temporal variability, with Chl-a ranging between 2.4 ± 0.2 mg·m−3 in April and 4.4 ± 1.0 mg·m−3 in July and no significant increasing or decreasing trend during the 10-year period. In waters where Chl-a was retrievable (i.e., where TSS is 10 mg·m−3) in summer. The study not only provides, for the first time, synoptic baseline information on the lake’s Chl-a distributions and potential eutrophic regions, but also demonstrates a practical approach that might be extended to assess eutrophication conditions in other inland waters.

The most recent Visible Infrared Imager Radiometer Suite (VIIRS) is not equipped with a spectral band to detect solar-stimulated phytoplankton fluorescence. The lack of such a band may affect the ability of VIIRS to detect and quantify harmful algal blooms (HABs) in coastal waters rich in colored dissolved organic matter (CDOM) because of the overlap of CDOM and chlorophyll absorption within the blue-green spectrum. A recent HAB dominated by the toxin-producing dinoflagellate Karenia brevis in the northeastern Gulf of Mexico, offshore of Florida's Big Bend region, allowed for comparison of the capacities of VIIRS and Moderate Resolution Imaging Spectroradiometer (MODIS) to detect blooms in CDOM-rich waters. Both VIIRS and MODIS showed general consistency in mapping the CDOM-rich dark water, which measured a maximum area of 8900 km2 by mid-July 2014. However, within the dark water, only MODIS allowed detection of bloom patches-as indicated by high normalized fluorescence line height (nFLH). Field surveys between late July and mid-September confirmed Karenia brevis at bloom abundances up to 20 million cells·L(-1) within these patches. The bloom patches were well captured by the MODIS nFLH images, but not by the default chlorophyll a concentration (Chla) images from either MODIS or VIIRS. Spectral analysis showed that VIIRS could not discriminate these high-phytoplankton water patches within the dark water due to its lack of fluorescence band. Such a deficiency may be overcome with new algorithms or future satellite missions such as the U.S. NASA's Pre-Aerosol-Clouds-Ecology mission and the European Space Agency's Sentinel-3 mission.

To prepare a recombinant lentiviral carring human lysosome-associated membrane protein type 2A (LAMP2A) gene shRNA, establish MDA-MB-231 cell line with a low expression of LAMP2A and observe the change in cell resistance to paclitaxel.Four shRNAs were designed according to the sequencing analysis of LAMP2A mRNA. The pGLV-EGFP-shRNA lentiviral vector was established by gene recombination technology and was confirmed by DNA sequencing. The lentiviral vector and the packaging vector were used to cotransfect the HEK293T cells to obtain the lentivirus against LAMP2A mRNA, and the titer of the virus was determined. The constructed shRNA lentivirus was applied to infect human breast cancer cell line MDA-MB-231, and then the cells were screened with puromycin for two weeks. The inhibitive efficacy of the shRNA on the LAMP2A protein was determined by Western blotting. After the breast cancer cell line with a low expression of LAMP2A was treated with three different concentrations of paclitaxel (1, 10, 100 nmol/L), MTT assay was performed to observe the difference in the proliferation ability between the control group and the low LAMP2A expression groups.DNA sequencing revealed that the recombinant lentiviral plasmid was correctly constructed with the virus titer reaching 2×10(8); TU/mL. The LAMP2A protein expression in the obtained breast cancer cell line dropped drastically. After the treatment with paclitaxel at 10 and 100 nmol/L respectively, the drug resistance of cells with a low expression of LAMP2A was notably weaker than that of the control group (P0.05).The recombinant shRNA lentiviral vector against human LAMP2A gene was successfully constructed, and the breast cancer cell line MDA-MB-231 transfected with it stably expressed a low level of LAMP2A. It was proved that the down-regulation of LAMP2A could reduce the resistance of breast cancer cells to paclitaxel.

Atmospheric correction of Landsat/TM and Landsat-7/Enhanced Thematic Mapper (ETM+) over aquatic environments is generally more demanding than over land because the signal from the water column is small. Because the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; Orbview-II satellite) and the Moderate Resolution Imaging Spectroradiometer (MODIS; Terra satellite) provide highly improved radiometric calibration, sensitivity, and spectral bands specifically designed for estimating aerosol radiance and its spectral quality, we attempted a multiplatform assessment of the path radiance and diffuse transmittance. Using SeaWiFS and ancillary data, we estimated the ETM+ path radiance and found that for a typically clear atmosphere, without knowledge of aerosol type (difficult to estimate with ETM+ data alone), the errors in the estimated aerosol radiance in Bands 1 and 2 can be a few counts (1 count corresponds to 0.0786 and 0.0817 mW cm −2 μm −1 sr −1 for Bands 1 and 2, respectively), comparable to errors in the estimated Rayleigh radiance by ignoring polarization correction. The same method can also be used to cross-calibrate the ETM+ over clear water where the target radiance (water-leaving radiance) is known. For a windless day (28 July 1999, wind −1 ), ETM+ Bands 2 and 3 agreed with the SeaWiFS-predicted values to within 0.5 count (∼1.5–3.3% of the total signal), while Band 1 was a few counts higher (∼5%) than predictions, possibly due to polarization or calibration effects. For a high-wind day (5 February 2000, wind speed ∼10 m s −1 ), the agreement is less satisfactory due to uncertainties in estimating the whitecap contribution. However, the overall trend for all the bands remains the same over the period: the difference for Band 1 is consistently larger than for Bands 2 and 3. Based on these results, we propose to use Rayleigh and aerosol data estimated with SeaWiFS and/or MODIS for atmospheric correction of ETM+ over aquatic environments. We also propose to use SeaWiFS/MODIS for monitoring the long-term stability of the Landsat-7/ETM+ calibration as the mission progresses.

This paper aims to clarify the potential of the new Landsat 7/Enhanced Thematic Mapper Plus (ETM+) sensors for change detection in coral reef environments. We processed images of two reef sites in Florida and Hawaii acquired over short time intervals (2 weeks and 3 months). During these periods, reefs were not affected by major disturbances (phase shift, strategy shift, bleaching, and hurricanes). This stability allowed us to assess the bias in change detection analysis. Two methods for change detection analysis were applied. The first one estimates the atmospheric conditions (Rayleigh and aerosol radiances, ozone and diffuse transmittances) using an ETM+/SeaWiFS multisensor approach. The second method is an empirical correction based on pseudoinvariant features that compensates for different atmospheric conditions as well as for any sensor (noise) or environmental (water column, sea surface state) conditions. The atmospheric correction alone did not provide an accurate match in images across time due to significant whitecaps and possible sun glint and its products required an empirical adjustment. Therefore, for the images in this study there was not substantial benefit in performing an atmospheric correction compared to an empirical correction alone. Both methods resulted in a minimum uncertainty of 4, 3, and 3 digital counts, respectively, in ETM+ Bands 1–3. Finally, we completed the study of real images by the analysis of ETM+ reflectance spectra for a large variety of coral reef objects. We concluded that the assessment of the rates of change in three ubiquitous classes ‘sand,’ ‘background’ (including rubble, pavement, and heavily grazed dead coral structure), and ‘foreground’ (including living corals and macroalgae) emerges as the most reproducible and feasible application for the ETM+ sensor.

Various subtle but important digitization round-off and noise errors are found in SeaWiFS imagery. These errors often cause large relative errors at a pixel and cause pixelization or “speckling” across the image, which is particularly obvious in the SeaWiFS chlorophyll standard product. Using simulations and current SeaWiFS algorithms, we show the effect of digitization-noise errors on the SeaWiFS ocean-color data products. It is found that the SeaWiFS mission goals, namely to estimate water-leaving radiances to within ±5% and chlorophyll-a concentrations to within ±35% for Case I waters, cannot always be met. For maritime aerosol conditions the errors in the estimated chlorophyll concentrations over oligotrophic waters can easily reach ±60% and the absolute values over adjacent pixels can vary 2–3 fold. Several schemes can be used to reduce this type of error, among which the spatial smoothing of the atmospheric-correction bands is recommended. This is because the errors in those bands are propagated and exaggerated to the visible bands and to the chlorophyll product through the atmospheric-correction process. The smoothing scheme, however, will cause more pixels to be discarded over cloud edges. Ultimately, a significant increase in both digitization bits and sensitivity is essential to achieve the stated mission goals. Such improved specifications are available on MODIS.

The current SeaWiFS algorithms frequently yield negative water-leaving radiance values in turbid Case II waters primarily because the water-column reflectance interferes with the atmospheric correction based on the 765-nm and 865-nm spectral bands. Here we present a simple, practical method to separate the water-column reflectance from the total reflectance at 765 nm and 865 nm. Assuming the type of aerosol does not vary much over relatively small spatial scales (∼50–100 km), we first define the aerosol type over less turbid waters. We then transfer it to the turbid area by using a “nearest neighbor” method. While the aerosol type is fixed, the concentration can vary. This way, both the aerosol reflectance and the water-column reflectance at 765 nm and 865 nm may be derived. The default NASA atmospheric correction scheme subsequently is used to obtain the aerosol scattering components at shorter wavelengths. This simple method was tested under various atmospheric conditions over the Gulf of Mexico, and it proved effective in reducing the errors of both the water-leaving radiance and the chlorophyll concentration estimates. In addition, in areas where the default NASA algorithms created a mask due to atmospheric correction failure, water-leaving radiance and chlorophyll concentrations were recovered. This method, in comparison with field data and other turbid water algorithms, was tested for the Gulf of Maine and turbid, posthurricane Gulf of Mexico waters. In the Gulf of Maine it provided more accurate retrievals with fewer failures of the atmospheric correction algorithms. In the Gulf of Mexico it provided far fewer pixels with atmospheric failure than the other methods, did not overestimate chlorophyll as severely, and provided fewer negative water-leaving radiance values. Background Since the launch of the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) aboard the SeaStar satellite in August 1997, global ocean color data are available to the science community on a regular basis. SeaWiFS is superior to the original Coastal Zone Color Scanner (CZCS, Hovis et al., 1980 ). It has much higher radiometric sensitivity (10 bits versus 8 bits) and additional spectral bands to aid in atmospheric correction and bio-optical applications. Specifications called for uncertainties less than ±5% in retrieved water-leaving radiance and less than ±35% in chlorophyll a concentration ([chl a]) in Case I waters ( Hooker et al., 1992 ; “Case I” defined in Morel and Prieur, 1977 ). SeaWiFS, however, generally fails to deliver such fidelity in turbid or shallow coastal waters (Case II waters). Turbid water constituents (suspended sediments, bubbles, etc., or bottom reflection) can contribute significant amounts of radiance to the atmospheric correction bands (765 nm and 865 nm). This will induce large errors when applying the standard atmospheric correction scheme since in that scheme the water-leaving radiance is assumed to be negligible in the near-infrared (IR) part of the spectrum (Gordon and Wang, 1994) . Also, in turbid Case II waters, the current band ratio bio-optical algorithm does not work well, simply because there are often other constituents (e.g., colored dissolved organic matter, or CDOM) whose optical properties may not covary with phytoplankton pigment concentrations Morel and Prieur 1977 , Carder et al. 1991 , Carder et al. 1999 , Muller-Karger et al. 1991 .

Optical remote sensing systems aboard geostationary platforms can provide high-frequency observations of bio-optical properties in dynamical coastal/oceanic waters. From the end-user standpoint, it is recognized that the fidelity of daily science products relies heavily on the radiometric sensitivity/performance of the imaging system. This study aims to determine the theoretical detection limits for bio-optical properties observed diurnally from a geostationary orbit. The analysis is based upon coupled radiative transfer simulations and the minimum radiometric requirements defined for the GEOstationary Coastal and Air Pollution Events (GEO-CAPE) mission. The diurnal detection limits are found for the optically active constituents of water, including near-surface concentrations of chlorophyll-a (CHL) and total suspended solids (TSS), and the absorption of colored dissolved organic matter (aCDOM). The diurnal top-of-atmosphere radiance (Lt) is modeled for several locations across the field of regard (FOR) to investigate the radiometric sensitivity at different imaging geometries. It is found that, in oceanic waters (CHL=0.07 mg/m3), detecting changes smaller than 0.01 mg/m3 in CHL is feasible for all locations and hours except for late afternoon observations on the edge of the FOR. For more trophic/turbid waters (0.6

Ever since the first Earth-observing satellite was launched, it became the dream of oceanographers to measure ocean chlorophyll a from space. Through more than a decade of dedicated theoretical, laboratory, and field research, the Coastal Zone Color Scanner was launched onboard NASA’s Nimbus-7 satellite in 1978. Originally intended as a proof-of-concept mission, the CZCS endured well beyond its two-year design life (1978–1986), and provided oceanographers with clear evidence that ocean chlorophyll a could be observed from space. Continued community effort led to the successor missions of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, 1997–2010), Moderate Resolution Imaging Spectroradiometer (MODIS, 1999—present for Terra and 2002—present for Aqua), Medium Resolution Imaging Spectrometer (MERIS, 2002–2012), and other modern satellite instruments. This chapter provides a brief review of how oceanic chlorophyll a is “measured”, validated, and used in various research studies and applications including the ocean’s response to climate variability and the assessment of coastal ocean changes to help resource management. Particular emphasis is given to atmospheric correction, bio-optical inversion, and algorithm validation. Finally, future satellite ocean color missions and research directions to support these missions are briefly discussed.

In teaching introductory computer programming courses, problem solving with computers is an important topic and algorithm design is essential. We developed a team-based project to teach students solving real-world problem. Students are provided with six satellite images of the Deepwater Horizon oil spill in the Gulf of Mexico and asked to develop computer programs to outline oil contaminated areas. Working on the project in a team, students conducted initial analysis of the problem, identified patterns of oil slicks by visualizing satellite images, and designed algorithms to delineate the oil slicks. The open-ended problem allowed the students to gain experiences in user interface design, use of arrays, decision-making, and repetition with hands-on experience. The project has also been adapted in teaching classes of computer science general education and digital image processing.

Coastal regions around the globe represent a major source for anthropogenic aerosols in the atmosphere, but the surface characteristics may not be optimal for the Moderate Resolution Imaging Spectroradiometer (MODIS) algorithms designed for aerosol retrievals over dark land or ocean surfaces. Using data collected from 62 coastal stations worldwide by the Aerosol Robotic Network (AERONET) in 2002–2011, statistical assessments of uncertainties are conducted for coastal aerosol optical depth (AOD) retrieved from MODIS measurements aboard the Aqua satellite (i.e., the Collection 5.1 MYD04 data product generated by the MODIS atmosphere group). It is found that coastal AODs (at 550 nm) characterised respectively by the Dark Land algorithm and the Dark Ocean algorithm all exhibit a log-normal distribution, which contrasts to the near-normal distribution of their corresponding biases. After data filtering using quality flags, the MODIS AODs from both the Dark Land and Dark Ocean algorithms over coastal regions are highly correlated with AERONET AODs (R2≈0.8), but both have larger uncertainties than their counterparts (of MODIS AODs) over land and open ocean. Overall, the Dark Ocean algorithm overestimates the AERONET coastal AOD by 0.021 for AOD 0.25. This dichotomy is shown to be related to the ocean-surface wind speed and cloud-contamination effects on the MODIS aerosol retrievals. Consequently, an empirical correction scheme is formulated that uses cloud fraction and sea-surface wind speed from Modern Era Retrospective-Analysis for Research and Applications (MERRA) to correct the AOD bias from the Dark Ocean algorithm, and it is shown to be effective over the majority of the coastal AERONET stations to (a) simultaneously reduce both the mean and the spread of the bias and (b) improve the trend analysis of AOD. Further correlation analysis performed after such an empirical bias correction shows that the MODIS AOD is also likely impacted by the concentration of suspended particulate matter in coastal waters, which is not taken into account during the MODIS AOD retrievals. While mathematically the MODIS AODs over the global coastal AERONET sites show statistically significant discrepancies (p

Oil pollution of natural waters represents a serious threat for aquatic ecosystems, and the assessment of the degree of pollution requiresmeasurement strategies including remote sensing and modeling. While surface oil pollution is relatively easy to detect with radar or opticalremote sensing, underwater oil emulsions can only be detected using visible light as an information carrier. Here the Michelson contrast ofsea area polluted by an oil-in-water emulsion under various wind conditions is simulated through Monte-Carlo modeling. The results showthe premise for optimal direction of observations in which the possibility of detecting the emulsified oil is maximized.