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Background Fecal calprotectin (FC) is a sensitive surrogate marker of mucosal inflammation in inflammatory bowel disease (IBD). Our aim was to asses the effect of anti-tumor necrosis factor alpha (TNFα) induction and maintenance therapy on FC levels in children with IBD. Methods The medical records of pediatric patients with IBD who were treated with anti-TNFα agents from 2015 to 2020 were reviewed retrospectively. We identified 63 patients who had FC levels measured prior to anti TNFα induction with sequential measurements during the first months of therapy. The main outcome measures were time to FC response according to cut-offs of 250,150,100 and 50µgr/gr. Variables affecting FC response were analyzed using multivariate analysis. Results Out of 63 patients, mean age 13.6 (±3) years, females 28(44.4%),54 (85.7%) had Crohn’s disease. The median (interquartile range) FC at baseline was 715 µgr/gr (312–1700). The outcomes of Conclusion In pediatric patients with IBD, FC response (

Background Anti-tumor necrosis factor alpha (anti-TNFα) therapy is commonly used to treat refractory pediatric inflammatory bowel disease (IBD). Prolonged use of anti-TNFα therapy has been linked to a number of adverse events. We aimed to assess the relationship between serum trough concentrations (TC) of anti-TNFα and adverse events rate among patients with pediatric IBD. Methods The medical records of 135 pediatric patients with IBD who were treated with anti-TNFα agents from 2015 to 2020 and had sequential monitoring of TC were reviewed retrospectively for the presence of adverse events (infusion reactions, infections, acute cutaneous reactions, psoriatiform rashes, elevated transaminases and others). The association between demographic or disease related variables and adverse events were analyzed using multivariate analysis. Results Out of 135 patients, [59 (43.7%) female, mean age at diagnosis 12.9 (±3)years, 111 (82.2%) Crohn’s disease] who had 1645 measurements of TC [1037(63%) infliximab, range 0-46 µgr/ml] during a median follow-up period of 1.7 years (1.1-2.7), we recorded 120 adverse events in 42 patients (31%). When analyzing TC as continuous measure or as a categorical measure (> or Conclusion Based on our cohort, higher TCs were not associated with higher rate of anti-TNF related adverse events whereas younger age at diagnosis increased the risk for such events. The study protocol was approved by the local Internal Review Board at the Rabin/Schneider Medical Center (RMC0320-10).

תקציר בעברית: במפרץ אילת מערכת אקולוגית ערכית וייחודית בקנה מידה לאומי ובין-לאומי, ועל כן קיימים חוקים ותקנות המגינים עליה מפני הפרעות מעשה ידי אדם. עם זאת, לרשות הטבע והגנים הסמכות להעניק היתרים חריגים לפגיעה בערכי טבע מוגנים לצורכי מחקר אקדמי ולצורכי תצוגה בפארק המצפה התת-ימי באילת (להלן – המצפה). היתרים אלה ניתנים מתוך הכרה בחשיבותו של המחקר האקדמי ובכך שתצוגת בעלי חיים ימיים במצפה חושפת בפני ציבור רחב את יופיים ואת ערכם של בתי גידול ימיים ומסייעת לקדם את שימורם. לעומת זאת, לגריעת ערכי טבע מהמערכת הטבעית מחיר אקולוגי בלתי מבוטל, כך שיש צורך לקבוע קווים אדומים לכמות שסביר לאשר לאסוף. במחקר זה מוצג מודל מתמטי המשמש לקביעת קווים אדומים לאיסוף ערכי טבע. המודל מחשב את הערכיות היחסית של מינים שונים במפרץ אילת, תוך שקלול פרמטרים המבטאים את פגיעות המין לאיסוף, את שכיחותו היחסית באזור האיסוף ואת חשיבותו לתפקודה התקין של המערכת האקולוגית. כחקר מקרה, מודל הערכיות שפותח במחקר מוצג כאן ככלי לקביעת קווים אדומים לאיסוף דגים ממפרץ אילת לצורך הצגתם במצפה. התוצאות מצביעות על פערים משמעותיים בין הכמות שהמצפה ביקש לתצוגות ובין הכמות שחושבה באמצעות המודל, והפערים בולטים בעיקר במינים בעלי הערכיות הגבוהה (פגיעים יותר או נדירים יחסית או חשובים לתפקודה התקין של המערכת האקולוגית). שיטה זו מיושמת כיום במפרץ אילת, והיא מפחיתה, ככל שניתן, את מידת הסובייקטיביות בקבלת ההחלטות ומבססת אותן על ידע ועל הנתונים הטובים ביותר שקיימים מאזור האיסוף, ועל מדדים ביולוגיים, פיזיולוגיים ואקולוגיים של המינים השונים. השיטה המוצגת במחקר זה עוסקת בדגים, אך ניתן ליישם את עקרונותיה גם עבור קבוצות טקסונומיות אחרות.

Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton is constrained by rapid sinking and slow dissolution dust-bound iron (dust-Fe). Colonies of the globally important cyanobacterium, Trichodesmium, overcome these constraints by efficient dust capturing and active dust-Fe dissolution. In this study we examined the ability of Trichodesmium colonies to maximize their Fe supply from dust by selectively collecting Fe-rich particles. Testing for selectivity in particle collection, we supplied ~600 individual colonies, collected on multiple days from the Gulf of Aqaba, with natural dust and silica minerals that were either cleaned of or coated with Fe. Using a stereoscope, we counted the number of particles retained by each colony shortly after addition and following 24 h incubation with particles, and documented translocation of particles to the colony core. We observed a strong preference for Fe-rich particles over Fe-free particles in all tested parameters. Moreover, some colonies discarded the Fe-free particles they initially collected. The preferred collection of Fe-rich particles and disposal of Fe-free particles suggest that Trichodesmium can sense Fe and selectively choose Fe-rich dust particles. This ability assists Trichodesmium obtain Fe from dust and facilitate its growth and subsequent contribution to nutrient cycling and productivity in the ocean.

The zooxanthellate hydrocoral Millepora dichotoma is an important framework builder of shallow reefs in the Gulf of Aqaba (Red Sea). In this study, we document and character- ize the emergence of multifocal bleaching (MFB), a new syndrome in M. dichotoma. MFB is char- acterized by bleached spots scattered over the colony. The establishment of MFB in M. dichotoma at the study site was surprisingly rapid. We first noticed this phenomenon and assessed its preva- lence in February 2010, and re-assessed it 1 yr later, in February 2011. The prevalence of MFB along the reef crest at a depth of 0.5 m is extremely high (63 and 67% in 2010 and 2011, respec- tively), significantly higher than along the fore-reef at a depth of 2.5 m (16 and 31% in 2010 and 2011, respectively). Spatial analyses were used to characterize the distribution of MFB across 2 spatial scales on the reef: among-transects scale (

Hydrogen peroxide (H2O2), a common reactive oxygen species, plays multiple roles in coral health and disease. Elevated H2O2 production by the symbiotic algae during stress may result in symbiosis breakdown and bleaching of the coral. We have recently reported that various Red Sea corals release H2O2 and antioxidants to their external milieu, and can influence the H2O2 dynamics in the reef. Here, we present a laboratory characterization of H2O2 and antioxidant activity release kinetics by intact, non-stressed Stylophora pistillata. Experimenting with bleached and non-bleached corals and different stirring speeds, we explored the sources and modes of H2O2 and antioxidant release. Since H2O2 is produced and degraded simultaneously, we developed a methodology for resolving the actual H2O2 concentrations released by the corals. H2O2 and antioxidant activity steadily increased in the water surrounding the coral over short periods of 1–2 h. Over longer periods of 5–7 h, the antioxidant activity kept increasing with time, while H2O2 concentrations were stabilized at ~ 1 μM by 1–3 h, and then gradually declined. Solving for H2O2 release, corals were found to release H2O2 at increasing rates over 2–4 h, and then to slow down and stop by 5–7 h. Stirring was shown to induce the release of H2O2, possibly since the flow reduces the thickness of the diffusive boundary layer of the coral, and thus increases H2O2 mass flux. Antioxidant activity was released at similar rates by bleached and non-bleached corals, suggesting that the antioxidants did not originate from the symbiotic algae. H2O2, however, was not released from bleached corals, implying that the symbiotic algae are the source of the released H2O2. The observed flow-induced H2O2 release may aid corals in removing some of the internal H2O2 produced by their symbiotic algae, and may possibly assist in preventing coral bleaching under conditions of elevated temperature and irradiance.

The vermetid gastropod Dendropoma maxima is found in association with diverse coral species. This association is often characterized by the coral head covered by a wide mucus net secreted by the gastropod to trap food particles from the water column. Here we report on the quan- titative effect of the gastropod on the morphology of Stylophora pistillata, one of the most abundant branching corals on the reef flat in Eilat (Gulf of Aqaba/Eilat, Red Sea). The existence of D. maxima in the vicinity of corals plays a significant role in deforming coral morphology. Compared with corals located outside the influence range of D. maxima, affected corals were found to be approx. 52% lower in their vertical dimension and approx. 35% smaller in diameter, and their slenderness ratio (height:diameter ratio) was found to be approx. 35% smaller. In addition, we found that over the last decade the population of D. maxima on the reef flat in Eilat has significantly increased in density (by a factor of approx. 2.5). The reason for this dramatic increase is currently unknown. However, it may be linked to the reported eutrophication of the northern Gulf of Aqaba, as this kind of environmental shift enhances the competitive advantage of suspension feeders over corals. Thus, the increase in the gastropod abundance may be a precursor of change in the reef flat community structure.

[1] The dynamics of hydrogen peroxide (H2O2) was studied in the fringing coral reef off the coast of Eilat, Red Sea. Diurnal changes in H2O2 concentrations in the reef lagoon were typical of photochemically produced species. During the daytime H2O2 accumulated in the lagoon at low tide and exceeded open water concentrations by 100–250 nM. Elevated H2O2 decay kinetics (termed hereafter antioxidant activity) were also recorded in the lagoon at low tide. The observed antioxidant activities were high enough to moderate H2O2 accumulation in the lagoon. In pursuit of the antioxidant source, the ability of corals to release antioxidant activity to their surrounding water was examined in both natural and laboratory settings. Water collected in situ from surfaces of individual corals and next to a coral knoll contained high antioxidant activity. Incubation experiments revealed that many Red Sea corals release antioxidant activity to their external milieu. Besides serving a potential antioxidant source to the reef system, the antioxidant activity detected on coral surfaces enabled corals to lower H2O2 concentrations in their vicinity. The ability of corals to offset exogenous H2O2 was validated in incubations with Stylophora pistillata in the absence of mixing. Conversely, corals subjected to mixing in a beaker were found to release H2O2, implying that corals may act as both a sink and a source for H2O2 in the reef. This newly described ability of corals to change H2O2 dynamics by releasing both H2O2 and antioxidants may bare important implications for coral physiology and interactions with the environment.

The larval pool of coral reef fish has a crucial role in the dynamics of adult fish populations. However, large-scale species-level monitoring of species-rich larval pools has been technically impractical. Here, we use high-throughput metabarcoding to study larval ecology in the Gulf of Aqaba, a region that is inhabited by >500 reef fish species. We analysed 9,933 larvae from 383 samples that were stratified over sites, depth and time. Metagenomic DNA extracted from pooled larvae was matched to a mitochondrial cytochrome c oxidase subunit I barcode database compiled for 77% of known fish species within this region. This yielded species-level reconstruction of the larval community, allowing robust estimation of larval spatio-temporal distributions. We found significant correlations between species abundance in the larval pool and in local adult assemblages, suggesting a major role for larval supply in determining local adult densities. We documented larval flux of species whose adults were never documented in the region, suggesting environmental filtering as the reason for the absence of these species. Larvae of several deep-sea fishes were found in shallow waters, supporting their dispersal over shallow bathymetries, potentially allowing Lessepsian migration into the Mediterranean Sea. Our method is applicable to any larval community and could assist coral reef conservation and fishery management efforts.

Coral bleaching events (BEs) are occurring in coral reefs worldwide and are expected to become annual, triggered by seasonal changes in water temperature. The stony coral Oculina patag- onica experiences repeated seasonal BEs along the Israeli Mediterranean coast. It thus constitutes a good model for assessing the potential effects of expected repeated BEs on coral physiology. Previous studies have shown that the overlap between bleaching and reproduction seasons in O. patagonica impedes gametogenesis. In the present study, we assessed the effect of bleaching on gametogenesis of populations commonly undergoing repeated seasonal BEs, and compared it with the effect of first and second summer BEs on gametogenesis of a population that has not experienced a summer BE in recent years. Interestingly, we found no differences between bleached and non-bleached colonies in most of the reproductive parameters tested in populations undergoing repeated seasonal BEs. We did find, however, that a population that experienced a summer BE for the first time presented signifi- cantly lower reproductive parameters in bleached colonies when compared to non-bleached colonies. Furthermore, in the following year, such bleached colonies showed an improvement in reproductive performance when compared to the previous year. The remarkable differences in gametogenesis between colonies experiencing first summer BE and those experiencing repeated seasonal BEs may be the result of improved utilization of alternative energy sources. This study pro- vides the first evidence for notable gametogenesis in corals undergoing repeated bleaching, and sug- gests that adjustment processes may increase tolerance levels and may play a role in the ability of corals to overcome the expected repeated BEs.

Size-frequency distributions (SFDs) have been used to assess the ecological status of different populations in a variety of ecosystems and recently have become widely used to examine reef corals. SFDs may reflect the response of time-varying influences of the environment, including the intensity and frequency of disturbances and the degree of environmental degradation. Here we elucidate the biases that can arise in the application of popular and traditional sampling methods (e.g. quadrat, belt-transect, and line-intercept). We show that these biases on the estimated SFD arise due to boundary effects of the sampling units. Incorrect evaluations of SFDs may lead to biased estimations of the ecological status of coral populations and may result in, among other things, erroneous nature reserve management policies. Our analysis is based on analytical calculations, simulations, and field observations. We have developed simple mathematical corrections, which provide unbiased estimations for previously collected data acquired by these widely used methods. In addition, we offer alternative sampling methods that do not suffer from these shortcomings. Eliminating these types of sampling errors will not only provide better assessments of the status of a given coral reef, but will also make way for more precise comparisons among coral reefs in different regions. Although we discuss the biases of SFDs in regard to reef coral populations, the work is equally relevant in other ecological contexts.

Corals make use of different chemical compounds during interactions with prey, predators and aggressors. Hydrogen Peroxide (H2O2) is produced and released by a wide range of organisms as part of their defense against grazers or pathogens. In coral reefs, the large fluxes and relatively long half-life of H2O2, make it a potentially important info-chemical or defense molecule. Here we describe a previously unstudied phenomenon of rapid H2O2 release from the reef-building coral Stylophora pistillata during feeding on zooplankton and in response to chemical and physical stimuli. Following stimuli, both symbiotic and bleached corals were found to rapidly release H2O2 to the surrounding water for a short period of time (few minutes). The H2O2 release was restricted to the site of stimulus and an increase in physical stress and chemical stimuli concentration resulted in elevated H2O2 release. Omission of calcium (a key regulator of exocytotic processes) from the experimental medium inhibited H2O2 release. Hence we suggest that H2O2 is actively released in response to stimuli, rather than leaking passively from the coral tissue. We estimate that at the site of stimulus H2O2 can reach concentrations potentially high enough to deter predators or motile, potentially pathogenic, bacteria.

The House Crow (Corvus splendens) is a bioinvader to the Red Sea region and has been shown to negatively impact indigenous species. We describe attempts by House Crows to acquire an ordinarily inaccessible, high quality food source by mobbing Western Osprey (Pandion haliaetus) in large coordinated groups. The crows mobbed perched Osprey that had successfully caught fish in 176 observed attempts to steal the otherwise inaccessible food source. However, crows succeeded in forcing Osprey to abandon fish on only seven occasions (∼4%). The crows then jointly fed on the abandoned fish. The consistency in mobbing Osprey and the low rate of success suggests House Crows are aware of the energetic value of fish.

Reproductive development of anthozoans reveals wide range of breeding strategies. Here, we report the occurrence of trioecy in the sea anemone Aiptasia diaphana (co-occurrence of males, females, and hermaphrodites), which so far was well documented only in plants. Age-homogeneous populations were obtained from pedal lacerates (asexual propagules) and cultured under control conditions. Careful documentation of growth, gamete morphology, and vertebrate-like steroid (i.e., progesterone, testosterone, and estradiol) levels were carried out over a 9-wk period between 4 and 12 wk postlaceration (wpl). First phenotypic signs of gametes development were observed in 6-wk-old anemones, pointing to the differentiation of males and hermaphrodites. While the males exhibited cellular progression of spermatogenesis, the hermaphrodites underwent a process of sex allocation, giving rise to male, female, and hermaphrodite phenotypes. Testosterone levels were relatively high prior to gamete appearance (4 wpl) and l...

Reproductive development of anthozoans reveals wide range of breeding strategies. Here, we report the occurrence of trioecy in the sea anemone Aiptasia diaphana (co-occurrence of males, females, and hermaphrodites), which so far was well documented only in plants. Age-homogeneous populations were obtained from pedal lacerates (asexual propagules) and cultured under control conditions. Careful documentation of growth, gamete morphology, and vertebrate-like steroid (i.e., progesterone, testosterone, and estradiol) levels were carried out over a 9-wk period between 4 and 12 wk postlaceration (wpl). First phenotypic signs of gametes development were observed in 6-wk-old anemones, pointing to the differentiation of males and hermaphrodites. While the males exhibited cellular progression of spermatogenesis, the hermaphrodites underwent a process of sex allocation, giving rise to male, female, and hermaphrodite phenotypes. Testosterone levels were relatively high prior to gamete appearance (4 wpl) and later on during gamete maturation (10 wpl). Conversely, estradiol levels steadily increased from 6 to 10 wpl, reaching their peak concomitant with oocyte maturation. Interestingly, increased oocyte atresia incidences were recorded during 9-12 wpl, coinciding with declining levels of steroid hormones. These results point to a strong similarity between the activity of sex steroids in vertebrates and that of vertebrate-like sex steroids on critical stages of A. diaphana's sexual differentiation and gametogenic cycle. The reproductive characteristics of A. diaphana make this anthozoan an important model species for the study of evolutionary drivers and processes underlying sexual development.

Thermal imaging (TI) systems, transform the distribution of relative temperatures in a scene into a visible TV image. TIs differ significantly from regular TV images. Most TI systems allow their operators to select preferred polarity which determines the way in which gray shades represent different temperatures. Polarity may be set to either black hot (BH) or white hot (WH). The present experiments were designed to investigate the effects of polarity on object recognition performance in TI and to compare object recognition performance of experts and novices. In the first experiment, twenty flight candidates were asked to recognize target objects in 60 dynamic TI recordings taken from two different TI systems. The targets included a variety of human placed and natural objects. Each subject viewed half the targets in BH and the other half in WH polarity in a balanced experimental design. For 24 out of the 60 targets one direction of polarity produced better performance than the other. Although the direction of superior polarity (BH or WH better) was not consistent, the preferred representation of the target object was very consistent. For example, vegetation was more readily recognized when presented as dark objects on a brighter background. The results are discussed in terms of importance of surface determinants versus edge determinants in the recognition of TI objects. In the second experiment, the performance of 10 expert TI users was found to be significantly more accurate but not much faster than the performance of 20 novice subjects.

BACKGROUND: Transmission mechanisms of black-band disease (BBD) in coral reefs are poorly understood, although this disease is considered to be one of the most widespread and destructive coral infectious diseases. The major objective of this study was to assess transmission mechanisms of BBD in the field based on the spatio-temporal patterns of the disease. METHODOLOGY/PRINCIPAL FINDINGS: 3,175 susceptible and infected corals were mapped over an area of 10x10 m in Eilat (northern Gulf of Aqaba, Red Sea) and the distribution of the disease was examined monthly throughout almost two full disease cycles (June 2006-December 2007). Spatial and spatio-temporal analyses were applied to infer the transmission pattern of the disease and to calculate key epidemiological parameters such as (basic reproduction number). We show that the prevalence of the disease is strongly associated with high water temperature. When water temperatures rise and disease prevalence increases, infected corals exhibit aggregated distributions on small spatial scales of up to 1.9 m. Additionally, newly-infected corals clearly appear in proximity to existing infected corals and in a few cases in direct contact with them. We also present and test a model of water-borne infection, indicating that the likelihood of a susceptible coral becoming infected is defined by its spatial location and by the relative spatial distribution of nearby infected corals found in the site. CONCLUSIONS/SIGNIFICANCE: Our results provide evidence that local transmission, but not necessarily by direct contact, is likely to be an important factor in the spread of the disease over the tested spatial scale. In the absence of potential disease vectors with limited mobility (e.g., snails, fireworms) in the studied site, water-borne infection is likely to be a significant transmission mechanism of BBD. Our suggested model of water-borne transmission supports this hypothesis. The spatio-temporal analysis also points out that infected corals surviving a disease season appear to play a major role in the re-introduction of the disease to the coral community in the following season.

New flow reactor measurements are reported of the intrinsic kinetics of the gasification of solid boron by each of these important vapors: B2O3(g), O2(g), CO2(g), and H2O(g) at surface temperatures between 1330 and 2050 K. For illustrative purposes, our data for the remarkably efficient B2O3(g)/B(s) reaction and the O2(g)/B(s) reaction are used to discuss the expected sequence of rate-controlling processes for the combustion of individual B(s) particles in air under typical ramjet conditions. A diagram of (log-) particle diameter vs (log-) chamber pressure is shown to be particularly useful for this purpose, as well as to display the onset of noncontinuum behavior and the locus of expected particle extinction due to passivation associated with the kinetically controlled onset of condensed B2O3 on the gas/solid interface. In this way we show that, whereas most previous boron particle combustion and extinction laboratory experiments have been performed in the regime of gas-phase diffusion control, under conditions of actual ramjet interest the gas/solid kinetics for the efficient B2O3(g)/B(s) reaction and the slower O2(g)/B(s) reaction, as well as noncontinuum transport effects, become rate limiting.

Coastal marine reserves in general, and coral reef reserves in particular, are typically composed of scattered patches separated by uninhabited areas. Due to the sessile mode of life of adult corals, larval connectivity is often the only agent of gene flow between reef localities. In this study we examined the connectivity between populations of the common scleratinian coral Stylophora pistillata at the northern tip of the Gulf of Aqaba (Red Sea), using the rDNA ITS (internal transcribed spacer) as a molecular marker. Sequence comparisons among recruits indicated very similar, equally-diverse, assemblages of recruits in both the northern (highly affected by anthropogenic disturbances) and southern (less affected) study sites, implying a high larval connectivity or common sources of larval supply. By contrast, sequence diversity observed among adults declined sharply from southern to northern sites, accompanied by genetic differentiation of the respective populations. Based on Fu's Fs-test of selective neutrality, it may be suggested that various post-settlement selective regimes, presumably more intense in the northern sites, provide a reasonable explanation for the observed patterns of genetic diversity. The suggested hypothesis is supported by the sharper decline in sequence diversity found between recruits and adults in the northern sites. This study exemplifies the necessity to consider local selective factors, in addition to larval connectivity, when managing marine reserves.