Validation of a diet-induced Macaca fascicularis model of non-alcoholic steatohepatitis with dietary and pioglitazone interventions.

AIM: To develop an obese, insulin-resistant cynomolgus monkey model of non-alcoholic steatohepatitis (NASH) with fibrosis with a high fat/high cholesterol (HFHC) diet (with or without high fructose) and test its responsiveness to caloric restriction or pioglitazone. METHODS: First, two groups of monkeys (n = 24/group) with histologically proven NASH and fibrosis were fed the HFHC diet for 17 weeks. The treatment group was subjected to a 40% caloric restriction (CR) and had their diet switched from the HFHC diet to a chow diet (DSCR). Paired liver biopsies were taken before and 17 weeks after DSCR. Subsets of monkeys (nine/group) had whole liver fat content assessed by MRI. Next, two groups of monkeys with histologically proven NASH and fibrosis were treated with vehicle (n = 9) or pioglitazone (n = 20) over 24 weeks. RESULTS: The HFHC and DSCR groups lost 0.9% and 11.4% of body weight, respectively. After 17 weeks, non-alcoholic fatty liver disease activity score (NAS) improvement was observed in 66.7% of the DSCR group versus 12.5% of the HFHC group (P < .001). Hepatic fat was reduced to 5.2% in the DSCR group versus 23.0% in the HFHC group (P = .0001). After 24 weeks, NAS improvement was seen in 30% of the pioglitazone group versus 0% of the vehicle group (P = .08). CONCLUSIONS: Both weight loss induced by DSCR and treatment with pioglitazone improve the histological features of NASH in a diet-induced cynomolgus monkey model. This model provides a translational preclinical model for testing novel NASH therapies.

Seagrass blue carbon stocks and sequestration rates in the Colombian Caribbean.

Seagrass ecosystems rank amongst the most efficient natural carbon sinks on earth, sequestering CO2 through photosynthesis and storing organic carbon (Corg) underneath their soils for millennia and thereby, mitigating climate change. However, estimates of Corg stocks and accumulation rates in seagrass meadows (blue carbon) are restricted to few regions, and further information on spatial variability is required to derive robust global estimates. Here we studied soil Corg stocks and accumulation rates in seagrass meadows across the Colombian Caribbean. We estimated that Thalassia testudinum meadows store 241 ± 118 Mg Corg ha-1 (mean ± SD) in the top 1 m-thick soils, accumulated at rates of 122 ± 62 and 15 ± 7 g Corg m-2 year-1 over the last ~ 70 years and up to 2000 years, respectively. The tropical climate of the Caribbean Sea and associated sediment run-off, together with the relatively high primary production of T. testudinum, influencing biotic and abiotic drivers of Corg storage linked to seagrass and soil respiration rates, explains their relatively high Corg stocks and accumulation rates when compared to other meadows globally. Differences in soil Corg storage among Colombian Caribbean regions are largely linked to differences in the relative contribution of Corg sources to the soil Corg pool (seagrass, algae Halimeda tuna, mangrove and seston) and the content of soil particles < 0.016 mm binding Corg and enhancing its preservation. Despite the moderate areal extent of T. testudinum in the Colombian Caribbean (661 km2), it sequesters around 0.3 Tg CO2 year-1, which is equivalent to ~ 0.4% of CO2 emissions from fossil fuels in Colombia. This study adds data from a new region to a growing dataset on seagrass blue carbon and further explores differences in meadow Corg storage based on biotic and abiotic environmental factors, while providing the basis for the implementation of seagrass blue carbon strategies in Colombia.

Application of middle-down approach in quantitation and catabolite identification of protein by LC-high-resolution mass spectrometry.

Aim: To further enhance the detection sensitivity and increase resolving power of top-down intact protein bioanalysis, middle-down approach was explored. Materials & methods: An monoclonal antibody (mAb) was used as a model protein to evaluate quantitative bioanalytical assay performance and a disulfide linked dimer protein was investigated for its pharmacokinetics properties and catabolism in vivo by middle-down approach. Results & Conclusion: For quantitation of the mAb, different subunits generated by middle-down approach provided different level of signal improvement in biological samples with Lc and half Fc giving five-times better sensitivity than intact mAb. For the dimer protein, middle-down analysis by reduction enabled effective differentiation of the unchanged protein and its oxidized form, and clearly elucidated their respective proteolytic catabolites.

Conjugation of a peptide to an antibody engineered with free cysteines dramatically improves half-life and activity.

The long circulating half-life and inherently bivalent architecture of IgGs provide an ideal vehicle for presenting otherwise short-lived G-protein-coupled receptor agonists in a format that enables avidity-driven enhancement of potency. Here, we describe the site-specific conjugation of a dual agonist peptide (an oxyntomodulin variant engineered for potency and in vivo stability) to the complementarity-determining regions (CDRs) of an immunologically silent IgG4. A cysteine-containing heavy chain CDR3 variant was identified that provided clean conjugation to a bromoacetylated peptide without interference from any of the endogenous mAb cysteine residues. The resulting mAb-peptide homodimer has high potency at both target receptors (glucagon receptor, GCGR, and glucagon-like peptide 1 receptor, GLP-1R) driven by an increase in receptor avidity provided by the spatially defined presentation of the peptides. Interestingly, the avidity effects are different at the two target receptors. A single dose of the long-acting peptide conjugate robustly inhibited food intake and decreased body weight in insulin resistant diet-induced obese mice, in addition to ameliorating glucose intolerance. Inhibition of food intake and decrease in body weight was also seen in overweight cynomolgus monkeys. The weight loss resulting from dosing with the bivalently conjugated dual agonist was significantly greater than for the monomeric analog, clearly demonstrating translation of the measured in vitro avidity to in vivo pharmacology.

Amino acids are sensitive glucagon receptor-specific biomarkers for glucagon-like peptide-1 receptor/glucagon receptor dual agonists.

AIM: The aim of this study was to evaluate amino acids as glucagon receptor (GCGR)-specific biomarkers in rodents and cynomolgus monkeys in the presence of agonism of both glucagon-like peptide-1 receptor (GLP1R) and GCGR with a variety of dual agonist compounds. MATERIALS AND METHODS: Primary hepatocytes, rodents (normal, diet-induced obese and GLP1R knockout) and cynomolgus monkeys were treated with insulin (hepatocytes only), glucagon (hepatocytes and cynomolgus monkeys), the GLP1R agonist, dulaglutide, or a variety of dual agonists with varying GCGR potencies. RESULTS: A long-acting dual agonist, Compound 2, significantly decreased amino acids in both wild-type and GLP1R knockout mice in the absence of changes in food intake, body weight, glucose or insulin, and increased expression of hepatic amino acid transporters. Dulaglutide, or a variant of Compound 2 lacking GCGR agonism, had no effect on amino acids. A third variant with ~31-fold less GCGR potency than Compound 2 significantly decreased amino acids, albeit to a significantly lesser extent than Compound 2. Dulaglutide (with saline infusion) had no effect on amino acids, but an infusion of glucagon dose-dependently decreased amino acids on the background of GLP1R engagement (dulaglutide) in cynomolgus monkeys, as did Compound 2. CONCLUSIONS: These results show that amino acids are sensitive and translatable GCGR-specific biomarkers.

6-Benzhydryl-4-amino-quinolin-2-ones as Potent Cannabinoid Type 1 (CB1) Receptor Inverse Agonists and Chemical Modifications for Peripheral Selectivity.

A novel series of 6-benzhydryl-4-amino-quinolin-2-ones was discovered as cannabinoid type 1 receptor (CB1R) inverse agonists based on the high-throughput screening hit, compound 1a. Structure-activity relationships were studied to improve in vitro/in vivo pharmacology and restrict distribution to the peripheral circulation. We adopted several strategies such as increasing topological polar surface area, incorporating discrete polyethylene glycol side chains, and targeting P-glycoprotein (P-gp) to minimize access to the brain. Compound 6a is a P-gp substrate and a potent and highly selective CB1R inverse agonist, demonstrating excellent in vivo metabolic stability and a low brain to plasma ratio. However, brain receptor occupancy studies showed that compound 6a may accumulate in brain with repeat dosing. This was evidenced by compound 6a inhibiting food intake and inducing weight loss in diet-induced obese mice. Thus, a strategy based on P-gp efflux may not be adequate for peripheral restriction of the disclosed quinolinone series.

Superior Glycemic Control With a Glucose-Responsive Insulin Analog: Hepatic and Nonhepatic Impacts.

We evaluated the hepatic and nonhepatic responses to glucose-responsive insulin (GRI). Eight dogs received GRI or regular human insulin (HI) in random order. A primed, continuous intravenous infusion of [3-3H]glucose began at -120 min. Basal sampling (-30 to 0 min) was followed by two study periods (150 min each), clamp period 1 (P1) and clamp period 2 (P2). At 0 min, somatostatin and GRI (36 ± 3 pmol/kg/min) or HI (1.8 pmol/kg/min) were infused intravenously; basal glucagon was replaced intraportally. Glucose was infused intravenously to clamp plasma glucose at 80 mg/dL (P1) and 240 mg/dL (P2). Whole-body insulin clearance and insulin concentrations were not different in P1 versus P2 with HI, but whole-body insulin clearance was 23% higher and arterial insulin 16% lower in P1 versus P2 with GRI. Net hepatic glucose output was similar between treatments in P1. In P2, both treatments induced net hepatic glucose uptake (HGU) (HI mean ± SEM 2.1 ± 0.5 vs. 3.3 ± 0.4 GRI mg/kg/min). Nonhepatic glucose uptake in P1 and P2, respectively, differed between treatments (2.6 ± 0.3 and 7.4 ± 0.6 mg/kg/min with HI vs. 2.0 ± 0.2 and 8.1 ± 0.8 mg/kg/min with GRI). Thus, glycemia affected GRI but not HI clearance, with resultant differential effects on HGU and nonHGU. GRI holds promise for decreasing hypoglycemia risk while enhancing glucose uptake under hyperglycemic conditions.

Simultaneous Catabolite Identification and Quantitation of Large Therapeutic Protein at the Intact Level by Immunoaffinity Capture Liquid Chromatography-High-Resolution Mass Spectrometry.

As therapeutic recombinant fusion proteins become more widely applicable for the treatment of various types of diseases, there is an increased demand for universal methods such as liquid chromatography (LC)-mass spectrometry (MS) for the determination of their pharmacokinetic properties, particularly their catabolism. The most common approach of analyzing proteins by LC-MS is to digest them into peptides, which can serve as surrogates of the protein. Alternatively, we have developed a novel high-resolution mass spectrometry (HRMS) based approach for analyzing large-molecule proteins at the intact level in biological samples without digestion. We established an immunoaffinity capture LC-HRMS method to quantify the intact parent molecule while simultaneously identifying catabolites for recombinant fusion proteins. We describe this method using dulaglutide, a glucagon-like peptide 1 (GLP1)-Fc fusion protein. Two proteolytic sites within the GLP1 peptide sequence of dulaglutide were identified using this novel LC-HRMS analysis in vivo in mice. These proteolytic sites were identified with the intact molecule being quantified simultaneously. Together with the trypsin digestion based LC-MS/MS analysis using surrogate peptides from different domains of the analyte, an insightful understanding of the pharmacokinetics and in vivo biotransformation of dulaglutide was obtained. Thus, this method enables simultaneous acquisition of both intact drug concentration and important catabolite information for this recombinant fusion protein, providing valuable insight into the integrity of the molecule and its catabolism in vivo. This is critical for designing and screening novel protein therapeutics and for understanding their pharmacokinetics and pharmacodynamics. With continuing advancement of LC-HRMS and software, this method can be very beneficial in drug discovery and development.

Pioglitazone increases whole body insulin sensitivity in obese, insulin-resistant rhesus monkeys.

Hyperinsulinemic-euglycemic clamps are considered the "gold standard" for assessing whole body insulin sensitivity. When used in combination with tracer dilution techniques and physiological insulin concentrations, insulin sensitization can be dissected and attributed to hepatic and peripheral (primarily muscle) effects. Non-human primates (NHPs), such as rhesus monkeys, are the closest pre-clinical species to humans, and thus serve as an ideal model for testing of compound efficacy to support translation to human efficacy. We determined insulin infusion rates that resulted in high physiological insulin concentrations that elicited maximal pharmacodynamic responses during hyperinsulinemic-euglycemic clamps. These rates were then used with [U-13C]-D-glucose, to assess and document the degrees of hepatic and peripheral insulin resistance between healthy and insulin-resistant, dysmetabolic NHPs. Next, dysmetabolic NHPs were treated for 28 days with pioglitazone (3 mg/kg) and again had their insulin sensitivity assessed, illustrating a significant improvement in hepatic and peripheral insulin sensitivity. This coincided with a significant increase in insulin clearance, and normalization of circulating adiponectin. In conclusion, we have determined a physiological clamp paradigm (similar to humans) for assessing glucose turnover in NHPs. We have also demonstrated that insulin-resistant, dysmetabolic NHPs respond to the established insulin sensitizer, pioglitazone, thus confirming their use as an ideal pre-clinical translational model to assess insulin sensitizing compounds.

Pegylated Fgf21 rapidly normalizes insulin-stimulated glucose utilization in diet-induced insulin resistant mice.

Fibroblast growth factor 21 (FGF21) is a novel hormone-like polypeptide that when administered exogenously, has been shown to have beneficial effects on food intake, body weight, and metabolism. The in vivo mechanisms of action for its positive metabolic effects remain to be fully elucidated. It has been shown that PEGylation of human FGF21 at specific and preferred sites confer superior metabolic pharmacology. We therefore hypothesized that low doses of PEGylated (30K PEG on position Q108) FGF21 (PEG30-Q108) would improve insulin action, independent of any effect on food intake or body weight. We identified a dose (0.25mg/kg) that had no effect on food intake or body weight, yet did show beneficial metabolic effects. Four groups of 12 weeks, high-fat fed, insulin resistant mice were studied: mice dosed subcutaneously once with vehicle or 0.25mg/kg of PEG30-Q108 24h before the experiment, or mice dosed 4 times over 2 weeks with vehicle or PEG30-Q108. Conscious, unrestrained mice were fasted for 5h and underwent a hyperinsulinemic-euglycemic clamp. Both PEG30-Q108 treatments significantly lowered fasting insulin compared to vehicle, with no difference in food intake or body weight. Insulin-stimulated whole body glucose utilization was normalized to that of lean mice with both PEG30-Q108 treatments compared to vehicle. This accounted for all of the enhanced insulin action, as there was no improvement in insulin's ability to suppress endogenous glucose production. In line with these findings, neither PEG30-Q108 treatment lowered hepatic triglycerides. These results demonstrate the profound ability of PEG30-Q108 to increase whole body insulin sensitivity.

Relationship between glucose volume of distribution and the extracellular space: a multiple tracer study.

Although the use of radioisotopes in the investigation of glucose metabolism dates back more than 50 years, several relevant quantitative aspects have not been definitively determined. These include the volume of distribution (V(d)) of glucose and recycling of glucose radioisotopes from liver glycogen. These problems are further complicated by methodological issues such as the following: (1) glucose tracers have different metabolic fates that may influence volume estimates, and (2) the calculation method needs to be based on physical principles to avoid some limitations of compartmental models. To address these issues, we administered boluses of an extracellular marker ([1-(14)C]-l-glucose, 30 µCi) and 2 glucose tracers ([2-(3)H]-d-glucose and [3-(3)H]-d-glucose, 120 µCi of each), followed by a 1-mg glucagon bolus (in the presence of somatostatin) 245 minutes later, in conscious beagles to account for potential problems in recycling of the label through glycogen. We used modeling methods based on physical principles (circulatory model), which yield volume estimates with a clear physiological interpretation. Glucose V(d) (mL/kg) were 204 ([1-(14)C]-l-glucose), 191 ([2-(3)H]-d-glucose), and 206 ([3-(3)H]-d-glucose). These values were not different and correlated. The amount of recycled [3-(3)H]-d-glucose in response to glucagon was small (∼1.7% of the injected tracer dose). An additional result of this analysis is the determination of the parameters of the circulatory model in beagles for the standard [3-(3)H]-d-glucose tracer. Using multiple tracers in beagles and calculation methods based on physical principles, we have provided direct proof that the glucose V(d) equals the extracellular space in beagles under basal conditions.

Intracerebroventricular leptin infusion improves glucose homeostasis in lean type 2 diabetic MKR mice via hepatic vagal and non-vagal mechanisms.

MKR mice, lacking insulin-like growth factor 1 receptor (IGF-1R) signaling in skeletal muscle, are lean yet hyperlipidemic, hyperinsulinemic, and hyperglycemic, with severe insulin resistance and elevated hepatic and skeletal muscle levels of triglycerides. We have previously shown that chronic peripheral administration of the adipokine leptin improves hepatic insulin sensitivity in these mice independently of its effects on food intake. As central leptin signaling has been implicated in the control of peripheral glucose homeostasis, here we examined the ability of central intracerebroventricular leptin administration to affect energy balance and peripheral glucose homeostasis in non-obese diabetic male MKR mice. Central leptin significantly reduced food intake, body weight gain and adiposity, as well as serum glucose, insulin, leptin, free fatty acid and triglyceride levels relative to ACSF treated controls. These reductions were accompanied by increased fat oxidation as measured by indirect calorimetry, as well as increased oxygen consumption. Central leptin also improved glucose tolerance and hepatic insulin sensitivity determined using the euglycemic-hyperinsulinemic clamps relative to pair fed vehicle treated controls, as well as increasing the rate of glucose disappearance. Hepatic vagotomy only partially reversed the ability of central leptin to improve glucose tolerance. These results demonstrate that central leptin dramatically improves insulin sensitivity independently of its effects on food intake, in a lean mouse model of type 2 diabetes. The findings also suggest that: 1) both hepatic vagal and non-vagal pathways contribute to this improvement, and 2) central leptin alters glucose disposal in skeletal muscle in this model.

Temporal patterns in coral reef, seagrass and mangrove communities from Chengue bay CARICOMP site (Colombia): 1993-2008

Few monitoring programs have simultaneously assessed the dynamics of linked marine ecosystems (coral reefs, seagrass beds and mangroves) to document their temporal and spatial variability. Based on CARICOMP protocol we evaluated permanent stations in coral reefs, seagrass beds and mangroves from 1993 to 2008 in Chengue Bay at the Tayrona Natural Park, Colombian Caribbean. Overall, the studied ecosystems showed a remarkable stability pattern over the monitoring period. While there were annual variations in coral reefs (coral cover) and mangroves (litterfall) caused by hurricane Lenny in 1999, particular trends in seagrass (leaf area index and leaf productivity) appear to reflect the natural variability in this ecosystem. We suggest that monitoring sites at the three marine ecosystems had in general a healthy development in the last 16 years. Our results are critical to locally improve the management strategies (Tayrona Natural Park) and to understand the long-term dynamics of closely associated marine ecosystems in the Caribbean. Rev. Biol. Trop. 58 (Suppl. 3): 45-62. Epub 2010 October 01.

Pocos programas de monitoreo han estudiado simultáneamente la dinámica de ecosistemas marinos estrechamente relacionados (arrecifes coralinos, pastos marinos y manglares) para documentar su variabilidad espacial y temporal. Siguiendo el protocolo de monitoreo del programa CARICOMP, estaciones permanentes de monitoreo en estos ecosistemas fueron evaluadas entre 1993 y 2008 en la Bahía de Chengue del Parque Nacional Natural Tayrona (Caribe Colombiano). En general los ecosistemas monitoreados han presentado un patrón de estabilidad durante los años de estudio. Mientras los arrecifes coralinos (cobertura de coral) y manglares tuvieron algunas variaciones anuales debidas al paso del huracán Lenny en 1999, los pastos marinos registraron tendencias particulares de cambio (índicece de área foliar y productividad de hojas) que podrían estar reflejando la variabilidad natural de la pradera estudiada.Por lo tanto se sugiere que los sitios monitoreados en cada ecosistema han tenido un desarrollo saludable en los últimos 16 años. Estos resultados son importantes para mejorar localmente las estrategias de manejo (Parque Nacional Natural Tayrona) y para evaluar la dinámica a largo plazo en los ecosistemas marinos del Caribe.

Coral diseases and bleaching on Colombian Caribbean coral reefs.

Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC) has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá). The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10 x 2m) with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters) are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2), and Urabá had high numbers with bleaching (54.4 colonies/m2). Of the seven reported coral diseases studied, Dark Spots Disease (DSD), and White Plague Disease (WPD) were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A. grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years) variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few long-term monitoring studies on coral diseases worldwide.

Recent dynamics and condition of coral reefs in the Colombian Caribbean.

Long-term monitoring data provide a basis to recognize changes in coral reef communities and to implement appropriate management strategies. Unfortunately, coral reef dynamics have been poorly documented at any temporal scale in the Southern Caribbean. Through the "National Monitoring System of Coral Reefs in Colombia" (Spanish acronym: SIMAC), we assessed 32 permanent plots at different depth levels in six reefs areas of the Colombian Caribbean from 1998 to 2004. Temporal trends in coral and algal cover were evaluated by repeated measures ANOVA. The model included the effect of depth levels (a fixed effect), monitoring plots (a random effect) as a nested factor within depths, and time (repeated factor). We found high spatial variability in major benthic components. Overall means indicated that algae were the most abundant biotic component in nearly all areas, ranging from 30.3% at Rosario to 53.3% at San Andrés. Live coral cover varied considerably from 10.1% at Santa Marta up to 43.5% at Urabá. Coral and algae cover per se are not always accurate reef indicators and therefore they need supplementary information. Temporal analyses suggested relative stability of coral and algal cover along the study but the causes for the observed trends were rarely identified. A significant decrease (p = 0.042) in coral cover was only identified for some monitoring plots in Tayrona-time x plot (depth level) interaction, and importantly, few coral species explained this trend. Significant increase (p = 0.005) in algal cover was observed over time for most plots in Rosario. Temporal trajectories in algal cover were influenced by depth-significant time x depth interaction-in San Andrés (increase, p = 0.004) and Urabá (decrease, p = 0.027). Algae trends were mainly explained by changes in algal turfs. Monitoring programs must focus on the mechanisms mediating the changes, in particular those concerning coral recovery and reef resilience in the current context of climate change.

Agents of coral mortality on reef formations of the Colombian Pacific.

The National Monitoring System for Coral Reefs of Colombia (SIMAC) monitors the impact of some of the most important agents of coral tissue loss (bleaching and/or disease) in the Colombian Pacific coral formations since 1998. Physiological bleaching is among the main results of stress in the area. Signs of coral diseases resembling bacterial bleaching such as White Plague and White Band, were observed in Malpelo and Gorgona islands. Damage to the Pacific gorgonian Pacifigorgia spp., similar to those produced by Aspergillosis in Caribbean corals, was detected in Utria Bay. The presence of tumors in colonies of massive corals was also recorded. Even though coral diseases are globally widespread, their occurrence in American Pacific reefs has been poorly documented to date.

White plague-like coral disease in remote reefs of the Western Caribbean.

The health of coral reef communities has been decreasing over the last 50 years, due the negative effects of human activities combined with other natural processes. We present documentation of a White Plague Disease (WPD) outbreak in the Serrana Bank, an isolated Western Caribbean atoll with presumably inexistent pollutant inputs from local human settlements. In addition, this study summarizes seven years of observations on diseased corals in the nearby island of San Andrés, which in contrast is one of the most populated islands of the Caribbean. There was a massive coral mortality in the atoll lagoon (14 degrees 27'53.24", 80 degrees 14'22.27" W, and 12m depth) due to WPD on May 4 of 2003. Seventeen species were found dead or largely affected by the disease. The information resulting from GPS and manta-tow transects revealed that approximately 5.8 ha of reticulate Montastraea spp. patch reefs were lethally affected by the disease in the atoll. On May 8 of the same year we observed and calculated a mean coral cover of 7.03% (SD +/- 2.44), a mean diseased coral tissue cover of 5.5% (SD +/- 1.1) and a 13.4% (SD +/- 8.05) of recently dead coral covered with a thin filamentous algae layer; approximately 73% of mortalities caused by the disease occurred before the end of the outbreak. A rough estimate of 18.9% in recent coral cover reduction can be attributed to WPD. This represents about 82% of the total coral cover decline since 1995. Semi-enclosed environments such as atoll lagoons and the reticulate patch-reefs of Montastraea spp. seem to be particularly vulnerable to this kind of coral disease, which constitute an alert to increase the monitoring of the same kind of atoll environments. The WPD has been present in the area of the nearby island of San Andrés at a low prevalence level, with sporadic increasing peaks of disease proliferation. The peaks observed during 1999 and 2004 comprised increases of 266% and 355% respectively, suggesting an alarming progression of the disease in this area. This study includes new information of the epizoolotiology of White Plague Disease and documents the permanent prevalence and progression of the WPD in the area of San Andres Island.

Coral diseases and bleaching on Colombian Caribbean coral reefs

Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC) has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá). The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10x2m) with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters) are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2), and Urabá had high numbers with bleaching (54.4 colonies/m2). Of the seven reported coral diseases studied, Dark Spots Disease (DSD), and White Plague Disease (WPD) were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A.grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years) variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few long term monitoring studies on coral diseases worldwide. Rev. Biol. Trop. 58 (Suppl. 1): 95-106. Epub 2010 May 01.

Desde 1998 el "Sistema Nacional de Monitoreo de Arrecifes Coralinos de Colombia" SIMAC, ha observado la ocurrencia de enfermedades coralinas y blanqueamiento en arrecifes colombianos (estaciones fijas en la Isla de San Tayrona, Islas del Rosario, Islas de San Bernardo y Urabá Chocoano). Para estimar la ocurrencia se ha examinado anualmente un total de 126 bandas permanentes (10x2m), dispuestas en diferentes rangos de profundidad en las áreas arrecifales objeto de estudio. El análisis de la información obtenida entre 1998 y el 2004 revela que San Andrés presenta altos promedios de colonias enfermas (38.9 colonias/100m2) y que Urabá exhibe ésta condición para el blanqueamiento (54.4 colonias/100m2). Del total de siete enfermedades detectadas, se destacan por su presencia en todas las áreas y la ocurrencia interanual, los Lunares Oscuros (DSD) y la Plaga Blanca (WPD). Un total de 35 especies de corales pétreos fueron registradas con al menos una enfermedad y se encontró una alta ocurrencia de enfermedades en las principales especies formadoras de arrecifes. El blanqueamiento se halló presente en 34 especies. Mientras WPD se halló en más especies (33), la DSD se registró un mayor número de veces. Agaricia agaricites fue la especie con mayor número de registros de DSD; por otra parte Siderastrea siderea fue vista un mayor número de veces con signos de blanqueamiento. Especies como Agaricia fragilis, A.grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, Mycetophyllia aliciae y Siderastrea radians son registradas por primera vez con presencia de enfermedades en Colombia. Cada área geográfica presentó variaciones espaciales (localidades, rangos de profundidad) y temporales (años) en cuanto a las prevalencias, tipos de enfermedades y especies de corales afectadas, que dificultan determinar patrones claramente definidos o tendencias generales para los arrecifes evaluados.

Recent dynamics and condition of coral reefs in the Colombian Caribbean

Long-term monitoring data provide a basis to recognize changes in coral reef communities and to implement appropriate management strategies. Unfortunately, coral reef dynamics have been poorly documented at any temporal scale in the Southern Caribbean. Through the "National Monitoring System of Coral Reefs in Colombia" (Spanish acronym: SIMAC), we assessed 32 permanent plots at different depth levels in six reefs areas of the Colombian Caribbean from 1998 to 2004. Temporal trends in coral and algal cover were evaluated by repeated measures ANOVA. The model included the effect of depth levels (a fixed effect), monitoring plots (a random effect) as a nested factor within depths, and time (repeated factor). We found high spatial variability in major benthic components. Overall means indicated that algae were the most abundant biotic component in nearly all areas, ranging from 30.3% at Rosario to 53.3% at San Andrés. Live coral cover varied considerably from 10.1% at Santa Marta up to 43.5% at Urabá. Coral and algae cover per se are not always accurate reef indicators and therefore they need supplementary information. Temporal analyses suggested relative stability of coral and algal cover along the study but the causes for the observed trends were rarely identified. A significant decrease (p=0.042) in coral cover was only identified for some monitoring plots in Tayrona-time x plot (depth level) interaction, and importantly, few coral species explained this trend. Significant increase (p=0.005) in algal cover was observed over time for most plots in Rosario. Temporal trajectories in algal cover were influenced by depth-significant time x depth interaction-in San Andrés (increase, p=0.004) and Urabá (decrease, p=0.027). Algae trends were mainly explained by changes in algal turfs. Monitoring programs must focus on the mechanisms mediating the changes, in particular those concerning coral recovery and reef resilience in the current context of climate change. Rev. Biol. Trop. 58 (Suppl. 1): 107-131. Epub 2010 May 01.

Este trabajo contiene el primer análisis temporal de la información obtenida por el Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC). Entre 1998 y el 2004 se monitorearon un total de 32 parcelas permanentes ubicadas a diferentes niveles de profundidad en seis áreas arrecifales del Caribe colombiano. Los patrones temporales de algas y corales fueron evaluados mediante análisis de varianza de medidas repetidas. Los promedios generales indicaron que las algas dominaron en la mayoría de las áreas evaluadas, variando de 30.3% (Rosario) hasta 53.3% (San Andrés). La cobertura coralina fluctuó considerablemente entre 10.1% (Santa Marta) y 43.5% (Urabá). Los arrecifes estudiados han permanecido relativamente estables durante el periodo evaluado en términos de algas y corales. El único cambio significativo en la cobertura se detectó en algunas parcelas de monitoreo del Tayrona, y pocas especies coralinas explicaron la tendencia de disminución. En Rosario se detectó una tendencia significativa de incremento para las algas en la mayoría de las parcelas. En San Andrés y Urabá las tendencias temporales (aumento y disminución respectivamente) se presentaron en ciertos niveles de profundidad. En estas dos áreas las tendencias en la cobertura de las algas fueron explicadas principalmente por cambios en los tapetes algales. En general las causas de los patrones observados no pudieron identificarse. Los programas de monitoreo deben evaluar no solo las tendencias generales de algas y corales sino también las de sus componentes (especies de coral y grupos funcionales de algas). Así mismo, deben enfocarse en evaluar los mecanismos involucrados en los cambios, en especial aquellos relacionados con la recuperación coralina y la resiliencia arrecifal, de manera que se pueda enfrentar el deterioro arrecifal en el actual contexto de cambio climático.

Agents of coral mortality on reef formations of the Colombian Pacific

The National Monitoring System for Coral Reefs of Colombia (SIMAC) monitors the impact of some of the most important agents of coral tissue loss (bleaching and/or disease) in the Colombian Pacific coral formations since 1998. Physiological bleaching is among the main results of stress in the area. Signs of coral diseases resembling bacterial bleaching such as White Plague and White Band, were observed in Malpelo and Gorgona islands. Damage to the Pacific gorgonian Pacifigorgia spp., similar to those produced by Aspergillosis in Caribbean corals, was detected in Utría Bay. The presence of tumors in colonies of massive corals was also recorded. Even though coral diseases are globally widespread, their occurrence in American Pacific reefs has been poorly documented to date. Rev. Biol. Trop. 58 (Suppl. 1): 133-138. Epub 2010 May 01.

A través del Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia-SIMAC se han evaluado algunos agentes de mortalidad coralina en el Pacifico Colombiano desde 1998. Uno de los principales factores que han contribuido a la pérdida de cobertura coralina han sido los eventos de blanqueamiento. No obstante, también se han observado signos que sugieren la presencia de enfermedades coralinas como el blanqueamiento bacteriano, la Plaga Blanca, la Banda Blanca, los tumores coralinos y la Aspergilosis en Pacifigorgia spp.. Aunque las enfermedades coralinas están globalmente distribuidas, su ocurrencia en el Pacifico tropical americano ha sido pobremente documentada. Esta nota incluye la ocurrencia de potenciales enfermedades coralinas en el Pacífico Colombiano.