Body-Plan Reorganization in a Sponge Correlates with Microbiome Change.

Mounting evidence suggests that animals and their associated bacteria interact via intricate molecular mechanisms, and it is hypothesized that disturbances to the microbiome influence animal development. Here, we show that the loss of a key photosymbiont (i.e., bleaching) upon shading correlates with a stark body-plan reorganization in the common aquarium cyanosponge Lendenfeldia chondrodes. The morphological changes observed in shaded sponges include the development of a thread-like morphology that contrasts with the flattened, foliose morphology of control specimens. The microanatomy of shaded sponges markedly differed from that of control sponges, with shaded specimens lacking a well-developed cortex and choanosome. Also, the palisade of polyvacuolar gland-like cells typical in control specimens was absent in shaded sponges. The morphological changes observed in shaded specimens are coupled with broad transcriptomic changes and include the modulation of signaling pathways involved in animal morphogenesis and immune response, such as the Wnt, transforming growth factor ß (TGF-ß), and TLR-ILR pathways. This study provides a genetic, physiological, and morphological assessment of the effect of microbiome changes on sponge postembryonic development and homeostasis. The correlated response of the sponge host to the collapse of the population of symbiotic cyanobacteria provides evidence for a coupling between the sponge transcriptomic state and the state of its microbiome. This coupling suggests that the ability of animals to interact with their microbiomes and respond to microbiome perturbations has deep evolutionary origins in this group.

Short-Term Exposure to High-Temperature Water Causes a Shift in the Microbiome of the Common Aquarium Sponge Lendenfeldia chondrodes.

Marine sponges harbor diverse microbiomes that contribute to their energetic and metabolic needs. Although numerous studies on sponge microbial diversity exist, relatively few focused on sponge microbial community changes under different sources of environmental stress. In this study, we assess the impact of elevated seawater temperature on the microbiome of cultured Lendenfeldia chondrodes, a coral reef sponge commonly found in marine aquaria. Lendenfeldia chondrodes exhibits high thermal tolerance showing no evidence of tissue damage or bleaching at 5 °C above control water temperature (26 °C). High-throughput sequencing of the bacterial 16S rRNA V4 region revealed a response of the microbiome of L. chondrodes to short-term exposure to elevated seawater temperature. Shifts in abundance and richness of the dominant bacterial phyla found in the microbiome of this species, namely Proteobacteria, Cyanobacteria, Planctomycetes, and Bacteroidetes, characterized this response. The observed resilience of L. chondrodes and the responsiveness of its microbiome to short-term increases in seawater temperature suggest that this holobiont may be capable of acclimating to anthropogenic-driven sublethal environmental stress via a re-accommodation of its associated bacterial community. This sheds a new light on the potential for resilience of some sponges to increasing surface seawater temperatures and associated projected regime shifts in coral reefs.

Apoptosis induced by a snake venom metalloproteinase from Bothrops alternatus venom in C2C12 muscle cells.

In this study, the apoptosis inducing effects of baltergin as well as its influence on cell adhesion and migration on muscles cells in vitro were studied. Morphological analysis made by scanning electron and phase contrast microscopy demonstrated typical futures of programmed cell death, apoptosis. This mechanism was confirmed by fluorescence staining, molecular analysis of endonuclease activity and increased mRNA expression level of two representative genes (p53 and bax). On the other hand, baltergin exert an inhibition effect on myoblast cell adhesion and migration in vitro probably through a mechanism that involves the interaction of this enzyme with cell integrins. In conclusion, our results suggest that the absence of appropriate extracellular matrix contacts triggers anoikis. Therefore, this is the first report that demonstrated the mechanism of programmed cell death triggered by baltergin, a PIII metalloprotease isolated from Bothrops alternatus venom, in a myoblast cell line.

Effects of Two Training Modalities on Body Fat and Insulin Resistance in Postmenopausal Women.

Henríquez, S, Monsalves-Alvarez, M, Jimenez, T, Barrera, G, Hirsch, S, de la Maza, MP, Leiva, L, Rodriguez, JM, Silva, C, and Bunout, D. Effects of two training modalities on body fat and insulin resistance in postmenopausal women. J Strength Cond Res 31(11): 2955-2964, 2017-Our objective was to compare the effects of a low-load circuit resistance training protocol and usual aerobic training in postmenopausal women. Postmenopausal women with at least 1 feature of the metabolic syndrome were randomly allocated to a low-load circuit resistance training protocol or traditional aerobic training in a braked cycle ergometer. The intervention consisted in supervised sessions lasting 40 minutes, 3 times per week, during 6 months. At baseline and at the end of the intervention, fasting serum lipid levels, serum interleukin 6, C-reactive protein, 8 isoprostanes, and insulin resistance (assessed through QUICKI and HOMA-IR) were measured. Body fat was measured by double-beam X-ray absorptiometry and by computed tomography densitometric quantification at lumbar 3 vertebral level. Twenty-one women aged 58 (54-59) years were allocated to aerobic training and 21 women aged 55 (52-61) years were allocated to the low-load circuit resistance training protocol. Eighteen and 16 women in each group completed the 6 months training period. Women in both groups experienced significant reductions in blood pressure, total body, subcutaneous, and intraabdominal body fat. Reductions in total cholesterol and triacylglycerol levels were also observed. No changes in insulin resistance indexes, 8 isoprostanes, C-reactive protein, or interleukin 6 were observed in either group. No significant differences between treatment groups were observed in any of the measured parameters. We conclude that low-load circuit resistance training and aerobic training resulted in the same reductions in body fat and serum lipid levels.

Associations between socioeconomic status, aging and functionality among older women.

To assess if there is an association between socioeconomic status and quality of life, functional status and markers of aging, we studied 86 women aged 73 ± 7 years, who answered the WHO Qol Bref quality of life survey. Mini mental state examination, timed up and go test, 12 minutes' walk, hand grip and quadriceps strength, dual X-ray absorptiometry (DEXA), carotid intima-media thickness and telomere length in peripheral leukocytes were measured. Successful aging was defined as a walking speed, handgrip strength, appendicular lean body mass, timed up and go and minimental values above cutoff points for disability. Participants with successful aging had a higher quality of life score and were more likely to live in rich municipalities. There was a positive correlation between telomere length, right handgrip strength and total fat free mass. Therefore, there is an association between socioeconomic status, successful aging and quality of life.

Aqueous two-phase systems: A simple methodology to obtain mixtures enriched in main toxins of Bothrops alternatus venom.

Phospholipase A2 (PLA2) and protease (P) are enzymes responsible of myotoxic, edematogenic and hemostasis disorder effects observed in the envenomation by Bothrops alternatus pitviper. Their partitioning coefficient (Kp) in different polyethyleneglycol/potassium phosphate aqueous two-phase systems (ATPSs) was determined in order to both achieve a better understanding of the partitioning mechanism and define optimal conditions for toxin isolation. Polyethyleneglycols (PEGs) of molecular weights 1000; 3350; 6000 and 8000; different temperatures (5, 20 and 37 °C) and phase volume ratios of 0.5; 1 and 2 were assayed. PLA2 partitioned preferentially to the top phase while P mainly distributed to the bottom phase. Either entropically- or enthalpically-driven mechanisms were involved in each case (PLA2 and P). The aqueous two-phase system formed by PEG of MW 3350 (12.20% wt/wt) and KPi pH 7.0 (11.82% wt/wt) with a volume ratio of one and a load of 1.25 mg of venom/g of system showed to be the most efficient to recover both enzymes. It allowed obtaining the 72% of PLA2 in the top phase with a purification factor of 2 and the 82% of P at the bottom phase simultaneously. A further adsorption batch step with DEAE-cellulose was used to remove satisfactorily the PEG from the top phase and recover the active PLA2. The proposed methodology is simple, inexpensive, and only requires professionals trained in handling basic laboratory equipment. It could be easily adoptable by developing countries in which the snakebite accidents cause considerable morbidity and mortality.

New immunization protocol to produce crotalic antivenom combining Crotalus durissus terrificus venom and its PLA2.

Antivenoms are usually obtained by animal immunization with successive inoculations of increasing sublethal amounts of venom, which may impair the animal health. The high lethality of venom requires prolonged immunization plans with small amounts of venom. Thus, we propose an alternative plan that includes a pre-immunization of the animal with phospholipase A2, the main crotoxin component, which is responsible for the whole venom lethality. For comparison, three different immunization schemes were designed: high dose protocol (HDP; 0.5-27 mg of venom), low dose protocol (LDP; 0.1-7 mg of venom) and Mix protocol (MP; preimmunization 0.1-1.2 mg of crotalic PLA2, and then 4.5-8 mg of venom). Antibody titers were determined by ELISA, in blood plasma obtained from the marginal vein of the ear. The neutralizing ability of the different sera obtained by all protocols (HDS, LDS and MS) was tested against the most important pharmacological activities of whole venom: PLA2 activity, myotoxicity, thrombin like activity and lethality. MS showed the best neutralizing efficacy and at the same time, it was obtained by an immunization protocol that takes account of animal health care, since it requires low quantities of venoms in comparison to traditional protocols.

[Evaluation of a program for management of metabolic syndrome in adults with overweight and obesity]. / Evaluación de un programa ministerial para manejo del síndrome metabólico en adultos con sobrepeso y obesidad.

BACKGROUND: The Chilean Ministry of Health developed a healthy lifestyles intervention directed to adults with overweight and cardiovascular risk factors, called "Program on Healthy Eating and Physical Activity" (PASAF). AIM: To evaluate the impact of PASAF on nutritional status and metabolic parameters. PATIENTS AND METHODS: We analyzed databases from three primary care centers belonging to a municipality of Metropolitan Santiago. We selected adults enrolled in the PASAF during three years (2007-2009). The program lasted four months and included an assessment of anthropometric and metabolic parameters at baseline and at the end, eight workshops with a nutritionist, seven with a psychologist and 32 sessions of physical activity. RESULT: We evaluated 526 subjects aged ≥18 years (93% females), of whom 85.6% attended the last appointment for assessment. Analyzing available data, attendance to workshops was <50% of the scheduled sessions. Weight, body mass index and waist circumference decreased significantly (median: -1.4 kg, -0.6 kg/m² and -3 cm, respectively). The median weight loss was 1.8% of initial weight and 17.1% of participants experienced a decrease ≥5% of their initial weight. There were significant improvements in lipid levels and blood pressure among participants with lower initial excess weight. A reduction in fasting blood glucose was observed only among subjects who lost ≥5% of their initial weight. CONCLUSIONS: The PASAF modestly reduced nutritional parameters. Correction of metabolic parameters was especially effective in less obese subjects. The attendance to workshops was low.

Ascorbyl palmitate (ASC16) as a potential inhibitor of toxicity induced by Crotalus durissus terrificus venom.

It is well known that C. d. terrificus venom causes pathophysiological effects such as neuropathies, coagulopathies, and even death. Previous studies have reported that ASC16 can interact with monomeric phospholipases A2 from the venom of various snake species (e.g., Vipera russelli and Echis carinatus). As a result, ASC16 has been proposed as an inhibitor of the toxic effects induced by the heterodimeric complex (crotoxin) and other components of the venom of C. d. terrificus. To investigate this further, in silico studies were designed using the crotoxin (CTX) protein complex as a model, and experimental assays were conducted to evaluate the inhibitory effect of ASC16 on CTX, as well as on other venom enzymes such as thrombin-like enzyme (TLE), phosphodiesterase (PDE) and l-aminoxidase (LAAO). For in vitro assays, specific substrates were used, and lethal activity was measured over 48 h using an in vivo murine experimental model (CF01). In silico studies have indicated that the hydrophilic portion of ASC16 adopts a stable conformation while interacting with the catalytic site of crotoxin. At the highest concentrations, ASC16 significantly inhibited the activities of PLA2 (40.89 ± 0.09 %), TLE (11.03 ± 0.69 %), PDE (51.33 ± 2.83 %), and LAAO (56.79 ± 2.91 %). Furthermore, ASC16 neutralized the 2 LD50 lethality of crotalic venom. These findings lay the groundwork for designing promising adjuvants that can facilitate the incorporation of a larger quantity of proteins in immunization schemes. Consequently, this approach aims to achieve higher antibody titers, reduce the number of required immunizations, and minimize local damage in the producer animal.

Potential low-impact immunogen for the production of anti-bothropic serum: Bothrops alternatus venom treated with Na2EDTA.

This study proposes an alternative method using Na2EDTA to neutralize B. alternatus venom and using it as an immunogen from the start of inoculation to minimize side effects and enhance antivenom production. To achieve this, 1.8 mg/mL of B. alternatus venom (B.aV) was treated with Na2EDTA, and any extra chelate was eliminated by filtering the resulting solution through a Sephadex G-25 column. Two groups of BALB/c mice were immunized subcutaneously on days 1, 15 and 30 with B.aV/Na2EDTA (45, 90, 135 µg/mouse) or B.aV (15, 30, 45 µg/mouse), respectively. Both formulations were emulsified with Freund's adjuvant (complete first and incomplete-booster). Blood samples were collected from each mouse on days 14, 29, 41, and 50 post-first immunization, and serum was separated for antibody detection. Animals were then sacrificed and lungs removed for histological analysis (hematoxylin-eosin). Immunoblotting analysis revealed that the sera from mice inoculated with B.aV/Na2EDTA (anti-B.aV/Na2EDTA) recognized the major venom proteins (20-66 kDa) similarly to the sera from mice inoculated with B.aV (anti-B.aV). The enzyme-linked immunosorbent assay results indicated that the anti-B.aV/Na2EDTA had a higher titer (5.76 × 104) than those the anti-B.aV (1.92 × 104). Additionally, sera from animals immunized with B.aV/Na2EDTA significantly neutralized proteolytic, indirect hemolytic and coagulant activity (p < 0.05). Finally, histological examination of the lungs of mice inoculated with B.aV/Na2EDTA showed normal appearance, while animals inoculated with B.aV showed interstitial lung injury (p < 0.05). In conclusion, the B.aV/Na2EDTA formulation, free of excess Na2EDTA, proved to be a promising candidate as an immunogen for antivenom production.

[Metabolic syndrome prevalence in Chilean children and adolescent with family history of chronic noncommunicable diseases]. / Prevalencia del sindrome metabolico en niños y adolescentes chilenos con historia familiar de enfermedades cronicas no transmisibles.

Family history (FH+) of non transmisible chronic diseases (NTCD) increase MetS risk. In Chile, the MetS affects 27% of overweight children, and fasting hyperglycemia is very low prevalent (4,0%). The objective was to study the prevalence of MetS and the cardiovascular risk factors (CVRF) in overweight children with a family background of NTCD and analyze its association with the number of relatives witth NTCD and with parental history (PH). In 183 overweight children (BMI > or = p85) mean age 11,8 +/- 1,8 (86 males) with a FH+ (parental or grandparental) of NTCD, were assessed the BMI z (CDC / NCHS), waist circumference, blood arterial pressure, fasting Glucose and Insulin (RIA), triglycerides, HDL chol. The MetS and the CVRF were diagnosed using the Cook phenotype and the insulin resistance (IR) through the HOMA-IR. Chi2, ANOVA, t Student and Willcoxon test were performed. The frequency of FH+ of DM2, hypertension and dyslipidemia were 81,4%, 88,0% and 71,6 % respectively. The MeTS prevalence was 46,5 % associated to overweight magnitude an parental history of NTCD. The prevalence of hypertriglyceridemia was 54,6%, while fasting hyperglycemia affected 31,4% of the sample. There was no association between number of relatives with NTCD and CV risk profile. We conclude that in overweight children with FH+ of NTCD, the prevalence of MetS, dyslipidemia and fasting hyperglycemia are significantly higher, than those observed in the general population of obese children.

European Lobster Larval Development and Fitness Under a Temperature Gradient and Ocean Acidification.

Climate change combined with anthropogenic stressors (e.g. overfishing, habitat destruction) may have particularly strong effects on threatened populations of coastal invertebrates. The collapse of the population of European lobster (Homarus gammarus) around Helgoland constitutes a good example and prompted a large-scale restocking program. The question arises if recruitment of remaining natural individuals and program-released specimens could be stunted by ongoing climate change. We examined the joint effect of ocean warming and acidification on survival, development, morphology, energy metabolism and enzymatic antioxidant activity of the larval stages of the European lobster. Larvae from four independent hatches were reared from stage I to III under a gradient of 10 seawater temperatures (13-24°C) combined with moderate (∼470 µatm) and elevated (∼1160 µatm) seawater pCO2 treatments. Those treatments correspond to the shared socio-economic pathways (SSP), SSP1-2.6 and SSP5-8.5 (i.e. the low and the very high greenhouse gas emissions respectively) projected for 2100 by the Intergovernmental Panel on Climate Change. Larvae under the elevated pCO2 treatment had not only lower survival rates, but also significantly smaller rostrum length. However, temperature was the main driver of energy demands with increased oxygen consumption rates and elemental C:N ratio towards warmer temperatures, with a reducing effect on development time. Using this large temperature gradient, we provide a more precise insight on the aerobic thermal window trade-offs of lobster larvae and whether exposure to the worst hypercapnia scenario may narrow it. This may have repercussions on the recruitment of the remaining natural and program-released specimens and thus, in the enhancement success of future lobster stocks.

Traces of Bothrops snake venoms in necrotic muscle preclude myotube formation in vitro.

Deficient skeletal muscle regeneration, which often leads to permanent sequelae, is a common clinical finding in envenomations caused by snakes of the family Viperidae, such as those of Bothrops alternatus and B. diporus in South America. The causes of such poor muscle regenerative outcome are still incompletely understood. Using a murine experimental model of envenomation by the venoms of these two species, we assessed whether traces of venom components that remain in muscle tissue days after envenomation affect myoblasts and myotube formation in culture. The kinetics of drop in venom concentration in the tissue was assessed by ELISA and Western blot, and by the quantification of venom phospholipase A2 activity. A rapid drop of venom components was observed in muscle, although a band of 58-63 kDa remained even 168 h after venom injection, and venom phospholipase A2 activity was detected in muscle tissue days after envenomation. Muscle homogenates from envenomated animals were cytotoxic to myoblasts in culture and inhibited the formation of myotubes even in conditions where homogenates were devoid of cytotoxicity. These deleterious effects were abrogated when homogenates were incubated with antivenom. Our findings agree with previous observations with the venom of Bothrops asper and provide further evidence that one of the causes of the poor skeletal muscle regeneration after Bothrops sp venom-induced myonecrosis is the deleterious action on myogenic cells of traces of venom components remaining in the tissue.

Photobiomodulation therapy on local effects induced by juvenile and adult venoms of Bothrops alternatus.

Bothrops snake envenomation is characterized by severe local manifestations such as pain, edema, inflammation, hemorrhage, and myonecrosis. Furthermore, it is described that venom from juvenile and adult snakes may have differences in their composition that can lead to differences in the evolution of the clinical manifestation of the victim. Photobiomodulation (PBM) has been shown to be an effective adjuvant therapy to serum therapy to reduce the local effects induced by bothropic snake venom. This study evaluated the effect of PBM on the local reaction, after Bothrops alternatus snake venom (BaV) injection, in its juvenile (BaJV) and adult (BaAV) stages. Balb/C mice were injected with the juvenile or adult venoms of BaV or saline solution (control group). PBM at a wavelength of 660 nm, 100 mW, 0.33 W/cm2, 40 s, and a 0.028 cm2 beam was applied transcutaneous to a single point with a radiant exposure of 4 J/cm2, 30 min after venom injection. Edema, inflammatory infiltrate, hyperalgesia, and myonecrosis were analyzed. Both venoms induced significant edema and myonecrosis in the gastrocnemius muscle. Hyperalgesia in the mice paw and a prominent leukocyte infiltrate into the peritoneum were also observed. PBM significantly reduced all evaluated parameters. In conclusion, PBM treatment was effective in reducing the local effects induced by B. alternatus venom at different stages of snake development and could be a useful tool as an adjuvant treatment for bothropic envenomation.

Corrigendum to "CpG-ODN formulated with a nanostructure as adjuvant for anticrotalic serum production. Studies in mice" [Toxicon 215 (2022) 28-36].

Antivenom is the only safe and effective treatment to neutralize snake venom. Specific anti-venom used to treat snake bite is usually obtained from horses after hyperimmunization with crude snake venom in combination with Freund's Adjuvant. Freund's complete and incomplete adjuvant can cause severe local and systemic acute and chronic inflammation, its potentially severe inflammatory effects have led many researchers to seek alternative immunological adjuvants. CpG-ODN formulated in a 6-O-ascorbyl palmitate nanostructure (Coa-ASC16) was more efficient as adjuvant than CpG-ODN alone using ovalbumin (OVA) as an antigen model. Particularly, immunization of mice with OVA/CpG-ODN/Coa-ASC16 resulted in high OVA specific antibody titers and IFN-γ and IL-17 secretion compared to immunization with OVA/CpG-ODN. First of all, we estimated the effect of Coa-ASC16 nanostructure preparation on venom activity. Additionally, in order to evaluate the immune response induced by this adjuvant strategy using Crotalus durissus terrificus (C. d. terrificus) venom (CdtV), we determined the titer of antibodies (IgG, IgG1 and IgG2) and their specificity. BALB/c mice were subcutaneously immunizated on days 0, 15 and 30 with CdtV/CpG-ODN/Coa-ASC16 or CdtV/Freund's Adyuvant (complete first and incomplete-booster) (dose/mice: CdtV: 6-10 µg, CpG-ODN: 30 µg). On day 45 mice were sacrificed. The neutralizing ability of serum from animals immunized with CdtV/CpG-ODN/Coa-ASC16 or CdtV/Freund's adjuvant was tested against PLA2 activity and lethality. In both immunized group mice, the antibody titers in plasma were high (1 × 105), with a similar IgG1/IgG2a ratio. The antibodies recognized phospholipase A2 and thrombin-like proteins, the main toxins from C. d. terrificus venom. Macroscopic and microscopic analysis at the site of injection of mice injected with Freund's adjuvant showed local damage (with non-infectious abscesses) and hypertrophy of inguinal lymph nodes, whereas mice injected with CpG-ODN/Coa/ASC16 did not. Our results show that CpG-ODN/Coa-ASC16 produces a humoral response as strong and specific as Freund's adjuvant, with minor or null local deleterious effect, demonstrating the potentiality and advisability of an alternative formulation as a new adjuvant option for future immunizations to produce C. d. terrificus antivenom.

High HOMA-IR, adjusted for puberty, relates to the metabolic syndrome in overweight and obese Chilean youths.

OBJECTIVE: To determine how the homeostasis model assessment of insulin resistance (HOMA-IR) is related to metabolic risk in a sample of overweight and obese Chilean youths accounting for Tanner stage. METHODS: A cross-sectional study assessing 486 overweight and obese youths (aged 5-15 years) recruited from the University of Chile, Pediatric Obesity Clinic. We measured anthropometry, Tanner stage, HOMA-IR, and laboratory tests related to metabolic risk. HOMA-IR was categorized by quartile for children (Tanner stages I and II) and adolescents (Tanner stage III and above) from a normative Chilean sample. RESULTS: Children and adolescents with HOMA-IR in the highest quartile were likely to have higher body mass index (BMI) Z-scores, elevated waist circumference, systolic and diastolic blood pressure, and triglycerides and low high-density lipoprotein. HOMA-IR had good negative predictive value for characteristics of the metabolic syndrome (MetS; 0.82). In a multivariate regression model, BMI Z-score [odds ratio (OR) 1.5] and HOMA-IR (OR 3.3) predicted 22% of the variance for the MetS, with 36% of the explained variance attributed to HOMA-IR. CONCLUSIONS: In a large clinical sample of overweight and obese Chilean youths, HOMA-IR ≥ 75th percentile was significantly associated with the cluster of factors referred to as the MetS. We emphasize the importance of establishing percentiles for HOMA-IR based on a normative sample and taking Tanner stage into account. Although BMI is easy to assess and interpret with minimal costs in a clinical setting, adding HOMA-IR explains more of the variance in the MetS than BMI Z-score alone.

Relationship of adiposity and insulin resistance mediated by inflammation in a group of overweight and obese Chilean adolescents.

The mild chronic inflammatory state associated with obesity may be an important link between adiposity and insulin resistance (IR). In a sample of 137 overweight and obese Chilean adolescents, we assessed associations between high-sensitivity C-reactive protein (hs-CRP), IR and adiposity; explored sex differences; and evaluated whether hs-CRP mediated the relationship between adiposity and IR. Positive relationships between hs-CRP, IR and 2 measures of adiposity were found. Hs-CRP was associated with waist circumference (WC) in boys and fat mass index (FMI) in girls. Using path analysis, we found that hs-CRP mediated the relationship between adiposity (WC and FMI) and the homeostatic model assessment of insulin resistance (HOMA-IR) (p < 0.05) in both sexes. Our novel finding is that inflammation statistically mediated the well described link between increased adiposity and IR.

Noisy waters can influence young-of-year lobsters' substrate choice and their antipredatory responses.

Offshore human activities lead to increasing amounts of underwater noise in coastal and shelf environments, which may affect commercially-important benthic invertebrate groups like the re-stocked Helgoland European lobster (Homarus gammarus) in the German Bight (North Sea). It is crucial to understand the impact tonal low-frequency noises, like maritime transport and offshore energy operations, may have on substrate choice and lobsters' behavior to assess potential benefits or bottlenecks of new hard-substrate artificial offshore environments that become available. In this study, we investigated the full factorial effect of a tonal low-frequency noise and predator presence on young-of-year (YOY) European lobsters' in a diurnal and nocturnal experiment. Rocks and European oyster shells (Ostrea edulis) were offered as substrate to YOY lobsters for 3 h. Video recordings (n = 134) allowed the identification of lobsters' initial substrate choice, diel activity and key behaviors (peeking, shelter construction, exploration and hiding). To ensure independence, YOY lobsters in the intermolt stage were randomly selected and assigned to the experimental tanks and used only once. We provide the first evidence that stressors alone, and in combination, constrain YOY lobsters' initial substrate choice towards rocks. During nighttime, the joint effect of exposure to a constant low-frequency noise and predator presence decreased antipredator behavior (i.e., hiding) and increased exploration behavior. Noise may thus interfere with YOY lobsters' attention and decision-making processes. This outcome pinpoints that added tonal low-frequency noise in the environment have the potential to influence the behavior of early-life stages of European lobsters under predator pressure and highlights the importance of including key benthic invertebrates' community relationships in anthropogenic noise risk assessments. Among others, effects of noise must be taken into consideration in plans involving the multi-use of any offshore area for decapods' stock enhancement, aquaculture, and temporary no-take zones.

South American snake venoms with abundant neurotoxic components. Composition and toxicological properties. A literature review.

In South America there are three snake genera with predominantly neurotoxic venoms: Crotalus, Micrurus and Hydrophis, which include nine species/subspecies, 97 species and a single marine species, respectively. Although accidents with neurotoxic venoms are less frequent than those with anticoagulant, cytotoxic or necrotic venoms (e.g. from Bothrops), they are of major public health importance. Venoms from genus Crotalus have been extensively studied, while data on the venoms from the other two genera are very limited, especially for Hydrophis. The venoms of North and South American Crotalus species show biochemical and physiopathological differences. The former species cause bothrops-like envenomation symptoms, while the latter mainly have neurotoxic and myotoxic effects, leading to respiratory paralysis and, occasionally, renal failure by myoglobinuria and death, often with no local lesions. Micrurus and Hydrophis also cause neurotoxic envenomations. Many studies have isolated, identified and characterized new enzymes and toxins, thus expanding the knowledge of snake venom composition. The present review summarizes the currently available information on neurotoxic venoms from South American snakes, with a focus on protein composition and toxicological properties. It also includes some comments concerning potential medical applications of elapid and crotalic toxins.

Physicochemical and biological characterization of nanovenoms, a new tool formed by silica nanoparticles and Crotalus durissus terrificus venom.

Nanoparticles (NPs) are being studied due to their potential use as therapeutic and immunomodulatory tools, including their ability to transport antigens with the aim to induce a specific immune response. The production of snake antivenoms (AV) involves several inoculations of venom (V) in the presence of adjuvants (ADJ) to improve the immune response of inoculated animals, causing a decrease in its quality and shelf life. Therefore, it is interesting to develop new strategies for reduce these side effects. For that reason, associating V to NPs to replace conventional ADJ could be a useful tool for future AV production. In this work, nanovenoms (NVs) were generated by the adsorption of Crotalus durissus terrificus (Cdt) V proteins over silica NPs (SiNPs) synthesized according to the Stöber method. Microphotographies obtained under Transmission Electron Microscopy (TEM) displayed a protein crown over NPs and Fourier Transform Infrared (FT-IR) presented the expected spectra for NVs resulting from the sum of those exhibited by Cdt V and SiNPs separately. SDS PAGE and immunoblotting assays confirmed the presence of proteins over SiNPs. Furthermore, the different enzymatic activities detected demonstrated that SiNPs were capable of binding V proteins preserving its activity and therefore would keep its native structure. In the same way, the NVs conserve the potential cytotoxic effects present in the V as we observed when culturing THP-1 cells with these complexes. This evidence allows us to infer that developed NVs could be used as a new platform for the production of antisera or for immunomodulatory therapies.