Smell loss associated with SARS-CoV-2 is not clinically different from other viruses: a multicenter cohort study.

BACKGROUND: Although the COVID-19 pandemic has increased the prevalence of cases with olfactory loss, other respiratory viruses can also cause this condition. We aimed to compare the prevalence of acute SARS-CoV-2 infection and other respiratory viruses in patients with sudden smell loss, and to assess the impact of SARS-CoV-2 viral load and co-infection on olfactory symptoms. METHODS: Patients with sudden smell loss were recruited in a multicenter prospective cohort study in 15 hospitals in Brazil. Clinical questionnaire, Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory test and nasopharyngeal swab to perform a PCR-based respiratory viral panel were collected at first visit (day 0) and 30 and 60 days after recruitment. RESULTS: 188 of 213 patients presented positive test result for SARS-CoV-2, among which 65 were co-infected with other respiratory viruses (e.g., rhinovirus, enterovirus, and parainfluenza). 25 had negative test results for SARS-CoV-2. Patients in both SARSCoV-2 and non-SARS-CoV-2 groups had objective anosmia (less than 2 points according to the psychophysical olfactory CCCRC) at day 0, with no significant difference between them. Both groups had significant smell scores improvement after 30 and 60 days, with no difference between them. Co-infection with other respiratory viruses, and SARS-CoV-2 viral load did not impact olfactory scores. CONCLUSION: Patients with sudden smell loss associated with SARS-CoV-2 and other respiratory viruses had similar presentation, with most participants initiating with anosmia, and total or near total recovery after 60 days. SARS-CoV-2 viral load and co-infections with other respiratory viruses were not associated with poorer olfactory outcomes.

Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector.

In this Letter, we present the design and performance of the frequency-dependent squeezed vacuum source that will be used for the broadband quantum noise reduction of the Advanced Virgo Plus gravitational-wave detector in the upcoming observation run. The frequency-dependent squeezed field is generated by a phase rotation of a frequency-independent squeezed state through a 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB of generated squeezing, up to 5.6 dB of quantum noise suppression has been measured at high frequency while close to the filter cavity resonance frequency, the intracavity losses limit this value to about 2 dB. Frequency-dependent squeezing is produced with a rotation frequency stability of about 6 Hz rms, which is maintained over the long term. The achieved results fulfill the frequency dependent squeezed vacuum source requirements for Advanced Virgo Plus. With the current squeezing source, considering also the estimated squeezing degradation induced by the interferometer, we expect a reduction of the quantum shot noise and radiation pressure noise of up to 4.5 dB and 2 dB, respectively.

Attraction of the sandfly Lutzomyia longipalpis to possible biomarker compounds from dogs infected with Leishmania infantum.

Lutzomyia longipalpis (Diptera: Psychodidae) is the primary vector of Leishmania infantum (Kinetoplastida: Trypanosomatidae) in the Americas. Studies have been carried out to identify new alternatives for monitoring and controlling this sandfly species, particularly with the use of chemical baits. The attractiveness of odours emitted by foxes and alcohols found in some plants has already been demonstrated in laboratory tests with Lu. longipalpis. However, no studies have evaluated the responses of these insects to volatile organic compounds (VOCs) emitted by dogs. The present study was carried out to investigate the effects on Lu. longipalpis of individual and blends of VOCs identified in hair from dogs infected with L. infantum. Effects in male and female Lu. longipalpis were assessed using wind tunnel methodology. Individual compounds including octanal, nonanal, decanal and heptadecane showed capacity for activating and/or attracting male Lu. longipalpis. Only decanal and nonanal showed effects on females. The combination of octanal, decanal and heptadecane increased activation and attraction behaviour in male sandflies, as did the blend of octanal and decanal. These findings indicate that VOCs emitted by dogs may be an interesting source of new attractants of sandflies.

Cardiovascular Adaptations Induced by Resistance Training in Animal Models.

In the last 10 years the number of studies showing the benefits of resistance training (RT) to the cardiovascular system, have grown. In comparison to aerobic training, RT-induced favorable adaptations to the cardiovascular system have been ignored for many years, thus the mechanisms of the RT-induced cardiovascular adaptations are still uncovered. The lack of animal models with comparable protocols to the RT performed by humans hampers the knowledge. We have used squat-exercise model, which is widely used by many others laboratories. However, to a lesser extent, other models are also employed to investigate the cardiovascular adaptations. In the subsequent sections we will review the information regarding cardiac morphological adaptations, signaling pathway of the cardiac cell, cardiac function and the vascular adaptation induced by RT using this animal model developed by Tamaki et al. in 1992. Furthermore, we also describe cardiovascular findings observed using other animal models of RT.

Influence of exposure parameters on the detection of simulated root fractures in the presence of various intracanal materials.

AIM: To investigate how the exposure parameters used when producing CBCT scans affect diagnostic accuracy when detecting simulated vertical root fractures and how various filling materials affect image quality. METHODOLOGY: A total of 160 extracted single-rooted human teeth were divided into four groups based on the materials within the root canals: unrestored, gutta-percha, metallic post and fibreglass post. Half of the sample of each group was selected for the induction of vertical root fractures. Each tooth was placed in an empty socket of a dry skull which was scanned on a CBCT unit (9000 3D scanner; Kodak Dental Systems, Carestream Health, Rochester, NY, USA) using the following exposure parameters: 74 kV/12 mA; 74 kV/10 mA; 74 kV/8 mA; 74 kV/6.3 mA; 70 kV/12 mA; 70 kV/10 mA; 70 kV/8 mA; 70 kV/6.3 mA. Two observers assessed all images using a 5-point confidence scale for fracture detection and a 4-point score for the presence of artefacts. Sensitivity, specificity, accuracy and area under ROC curve were compared by two-way anova and Tukey's test. Artefact formation was evaluated by descriptive statistics. RESULTS: There were no significant differences in the sensitivity (P = 0.370), specificity (P = 0.660), accuracy (P = 0.084) and area under the ROC curve (P = 0.674) values amongst the various exposure parameters within the same group. There were some significant differences when the groups were compared for each intracanal material. The sensitivity and accuracy of the group containing metallic posts were significantly lower than the unrestored and fibreglass post groups (P ≤ 0.017). CONCLUSION: The variations in exposure parameters did not interfere with the diagnosis of vertical root fractures, independent of the root canal restorative status. Metallic posts were associated with greater artefact formation and compromised the diagnostic performance. It is possible to decrease the kVp/mA settings to reduce the probability of biological effects due to radiation, without losing diagnostic accuracy.

Performance of an artefact reduction algorithm in the diagnosis of in vitro vertical root fracture in four different root filling conditions on CBCT images.

AIM: To evaluate the influence of an artefact reduction algorithm (ARA) and several root filling materials on the detection of root fractures on cone-beam computed tomography (CBCT) images. METHODOLOGY: Forty-four teeth were divided into control and fractured groups and scanned on a Picasso Trio CBCT device under four conditions: unrestored, filled with gutta-percha cones, cast-gold or fibreglass posts; either with or without applying the ARA. Three calibrated examiners assessed the images. ROC analysis, anova and pairwise Tukey LSD test were performed. RESULTS: No significant difference between the groups with and without the ARA was observed. There was no significant interaction between the algorithm and root condition. On the other hand, there was a significant difference in the mean values of sensitivity (Sn) and accuracy (Ac) amongst the different root filling groups (P ≤ 0.001). CONCLUSIONS: The application of the ARA did not influence the diagnosis of root fractures, and its effects did not depend on root conditions. In relation to the filling materials, gold posts reduced the overall CBCT diagnostic ability, regardless of the use of the ARA.

Antioxidant and haematological biomarkers in different groups of horses supplemented with polyunsaturated oil and vitamin E.

Oxidative stress has been correlated with pathologies that impair the performance of athlete horses. The aim of this study was to assess the effects of supplementation with a mixture of polyunsaturated oil and vitamin E on the antioxidant and haematological biomarkers of horses. Horses under maintenance care (n = 6) and horses in training (n = 10) received 100 and 300 ml of the oil mixture respectively. Supplementation was provided for a period of 8 weeks, together with isocaloric inclusion. Blood samples were collected at three time periods (pretest, after 4 weeks and after 8 weeks) to analyse the following: the red blood cell count (RBCc); haemoglobin (Hb); haematocrit (HT); leucocytes; lymphocytes; platelets; the mean corpuscular volume (MCV); the mean corpuscular haemoglobin concentration (MCHC); the standard deviation of the red blood cell distribution width (RDW-SD); the coefficient of variation of the red blood cell distribution width (RDW-CV); glutathione peroxidase (GPx); superoxide dismutase (SOD); uric acid (UrAc); total plasma proteins (TPP); and creatine kinase (CK). After the 8 weeks of supplementation, animals under maintenance care exhibited significant increases in SOD, UrAc, the white blood cell count (WBCc), the RDW-SD and the RDW-CV (p < 0.05). The animals in training exhibited increases in GPx, SOD and UrAc (p < 0.05). In conclusion, supplementation with polyunsaturated oil and vitamin E increases blood antioxidants among animals under maintenance and in training, with different trends, while contributing to the fight against oxidative stress in each group analysed.

Magnetic resonance imaging findings of true bifid mandibular condyle with duplicated mandibular fossa.

Bifid mandibular condyle (BMC) is a rare asymptomatic morphological alteration with no predilection for age group or gender. Its morphology varies from a shallow groove to two condylar heads with separate necks, oriented mediolaterally or anteroposteriorly. This report describes an unusual case of anteroposterior bifid condyle in a 39-year-old female patient with the main complaint of mouth-opening limitation and a deviation of the mandible to the left side. Magnetic resonance imaging (MRI) findings revealed a bifid condyle on the left side and duplicated mandibular fossa, with the articular disc over the anterior head. The MRI images in the open-mouth position revealed minimal movement of the condyle. Despite the increased number of mediolateral bifid mandibular condyle cases described in the literature, none of previously reported cases of BMC included an anteroposterior bifid condyle case with two distinct mandibular fossa.

Exosomal glypican-1 discriminates pancreatic ductal adenocarcinoma from chronic pancreatitis.

BACKGROUND AND AIMS: Pancreatic ductal adenocarcinoma (PDAC) diagnosis can be difficult in a chronic pancreatitis (CP) background, especially in its mass forming presentation. We aimed to assess the accuracy of glypican-1-positive circulating exosomes (GPC1+crExos) to distinguish PDAC from CP versus the state-of-the-art CA 19-9 biomarker. METHODS: This was a unicentric prospective cohort. Endoscopic ultrasound with fine-needle aspiration or biopsy and blood tests (GPC1+crExos and serum CA 19-9) were performed. RESULTS: The cohort comprised 60 PDAC and 29 CP (7 of which mass forming - MF) patients. Median levels of GPC1+crExos were significantly higher in PDAC (99.7%) versus CP (28.4%; p<0.0001) with an AUROC of 0.96 with 98.3% sensitivity and 86.2% specificity for a cut-off of 45.0% (p<0.0001); this outperforms CA 19-9 AUROC of 0.82 with 78.3% sensitivity and 65.5% specificity at a cut-off of 37 U/mL (p<0.0001). The superiority of% GPC1+crExos over CA 19-99 in differentiating PDAC from CP was observed in both early (stage I) and advanced tumors (stages II-IV). CONCLUSION: Levels of GPC1+crExos coupled to beads enable differential diagnosis between PDAC and CP including its mass-forming presentation.

Applicability of the PAINESD risk score for 30-day mortality prediction post ventricular tachycardia catheter ablation in Chagas disease.

PURPOSE: The PAINESD risk score was developed in 2015 as a tool to stratify the risk of acute hemodynamic decompensation during ventricular tachycardia (VT) ablation in structural heart disease patients and further then used for post procedure 30-day mortality prediction. The original cohort however did not include Chagas disease (ChD) patients. We aim to evaluate the relevance of the score in a ChD population. METHODS: The PAINESD risk score gives weighted values for specific characteristics (chronic obstructive pulmonary disease, age > 60 years, ischemic cardiomyopathy, New York Heart Association [NYHA] functional class 3 or 4, ejection fraction less than 25%, VT storm, and diabetes). The score was applied in a retrospective cohort of ChD VT ablations in a single tertiary center in Brazil. Data were collected by VT study reports and patient record analysis at baseline and on follow-up. RESULTS: Between January 2013 and December 2018, 157 VT catheter ablation procedures in 121 ChD patients were analyzed. Overall, 30-day mortality was 9.0%. Multivariate analysis correlated NYHA functional class (HR 1.78, 95% CI 1.03-3.08, P 0.038) and the need for urgent surgery (HR 31.5, 95% CI 5.38-184.98, P < 0.001), as well as a tendency for VT storm at presentation (HR 2.72, 95% CI 0.87-8.50, P 0.084) as risk factors for the primary endpoint. The median PAINESD risk score in this population was 3 (3-8). The area under the receiver operating characteristic (ROC) curve was 0.64 (95% CI 0.479-0.814). CONCLUSIONS: The PAINESD risk score did not perform well in predicting 30-day mortality in ChD patients. Pre-procedure NYHA functional class and the need for urgent surgery due to refractory pericardial bleeding were independently associated with increased 30-day mortality. Prospective studies are needed to take final conclusions in Chagas disease when using PAINESD score.

Reactive oxygen species and autophagy play a role in survival and differentiation of the phytopathogen Moniliophthora perniciosa.

The hemibiotrophic basidiomycete Moniliophthora perniciosa causes "witches' broom disease" in cacao (Theobroma cacao). During plant infection, M. perniciosa changes from mono to dikaryotic life form, an event which could be triggered by changes in plant nutritional offer and plant defense molecules, i.e., from high to low content of glycerol and hydrogen peroxide. We have recently shown that in vitro glycerol induces oxidative stress resistance in dikaryotic M. perniciosa. In order to understand under which conditions in parasite-plant interaction M. perniciosa changes from intercellular monokaryotic to intracellular dikaryotic growth phase we studied the role of glycerol on mutagen-induced oxidative stress resistance of basidiospores and monokaryotic hyphae; we also studied the role of H(2)O(2) as a signaling molecule for in vitro dikaryotization and whether changes in nutritional offer by the plant could be compensated by inducible fungal autophagy. Mono-/dikaryotic glycerol or glucose-grown cells and basidiospores were exposed to the oxidative stress-inducing mutagens H(2)O(2) and Paraquat as well as to pre-dominantly DNA damaging 4-nitroquinoline-1-oxide and UVC irradiation. Basidiospores showed highest resistance to all treatments and glycerol-grown monokaryotic hyphae were more resistant than dikaryotic hyphae. Monokaryotic cells exposed to 1microM of H(2)O(2) in glycerol-media induced formation of clamp connections within 2 days while 1mM H(2)O(2) did not within a week in the same medium; no clamp connections were formed in H(2)O(2)-containing glucose media within a week. Lower concentrations of H(2)O(2) and glycerol, when occurring in parallel, are shown to be two signals for dikaryotization in vitro and may be also during the course of infection. Q-PCR studies of glycerol-grown dikaryotic cells exposed to oxidative stress (10mM H(2)O(2)) showed high expression of MpSOD2 and transient induction of ABC cytoplasmic membrane transporter gene MpYOR1 and autophagy-related gene MpATG8. Expression of a second ABC transporter gene MpSNQ2 was 14-fold induced after H(2)O(2) exposure in glucose as compared to glycerol-grown hyphae while MpYOR1 did not show strong variation of expression under similar conditions. Glucose-grown dikaryotic cells showed elevated expression of MpATG8, especially after exposure to H(2)O(2) and 4-nitroquinoline-1-oxide. During different stages preceding basidiocarp formation MpATG8 and the two catalase-encoding genes MpCTA1 and MpCTT1 were expressed continuously. We have compiled our results and literature data in a model graph, which compares the in vitro and in planta development and differentiation of M. perniciosa with the help of physiological and morphological landmarks.

Serological testing for celiac disease in women with endometriosis. A pilot study.

PURPOSE OF INVESTIGATION: Celiac disease (CD) involves immunologically mediated intestinal damage with consequent micronutrient malabsorption and varied clinical manifestations, and there is a controversial association with infertility. The objective of the present study was to determine the presence of CD in a population of infertile women with endometriosis. METHODS: A total of 120 women with a diagnosis of endometriosis confirmed by laparoscopy (study group) and 1,500 healthy female donors aged 18 to 45 years were tested for CD by the determination of IgA-transglutaminase antibody against human tissue transglutaminase (t-TGA) and anti-endomysium (anti-EMA) antibodies. RESULTS: Nine of the 120 women in the study group were anti-tTGA positive and five of them were also anti-EMA positive. Four of these five patients were submitted to intestinal biopsy which revealed CD in three cases (2.5% prevalence). The overall CD prevalence among the population control group was 1:136 women (0.66%). CONCLUSION: This is the first study reporting the prevalence of CD among women with endometriosis, showing that CD is common in this population group (2.5%) and may be clinically relevant.

Correction: CpG island hypermethylation-associated silencing of non-coding RNAs transcribed from ultraconserved regions in human cancer.

In the original article the authors have noted that the wrong image was used to illustrate the Uc.346 + Lu1-Lu2-Lu3 subpanel of Figure 5a. The correct image is now provided as Figure 1 in this article. This change does not affect the legend of the figure, the results, or conclusions reported in the manuscript. The authors apologize for the error, and regret any inconvenience this may have caused.

Carbon source-dependent variation of acquired mutagen resistance of Moniliophthora perniciosa: similarities in natural and artificial systems.

The basidiomycete Moniliophthora perniciosa causes Witches' Broom disease in Theobroma cacao. We studied the influence of carbon source on conditioning hyphae to oxidative stress agents (H(2)O(2), paraquat, 4NQO) and to UVC, toward the goal of assessing the ability of this pathogen to avoid plant defenses involving ROS. Cells exhibited increased resistance to H(2)O(2) when shifted from glucose to glycerol and from glycerol to glycerol. When exposed to paraquat, cells grown in fresh medium were always more resistant. Apparently glycerol and/or fresh media, but not old glucose media, up-regulate oxidative stress defenses in this fungus. For the mutagens UVC and 4NQO, whose prime action on DNA is not via ROS, change of carbon source did not elicit a clear change in sensitivity/resistance. These results correlate with expression of fungal genes that protect against ROS and with biochemical changes observed in infected cacao tissues, where glycerol and high amounts of ROS have been detected in green brooms.

Effects of food availability and habitat features on the Ephemeroptera species composition at seasonal and spatial scales from neotropical floodplain rivers.

Brazilian floodplains have suffered great changes in their natural characteristics in recent decades, mainly in the flood pulse. The Upper Paraná River floodplain is one of the few places where are found remained areas in which such peculiar characteristics keep reflecting on its high biodiversity. Ephemeroptera nymphs are one of the higher density groups among benthic community, occurring in many water bodies like large rivers and secondary channels. We sought to understand which factors are needed for the species establishment and how much important is the species colonization, especially in environments with anthropogenic changes. The marginal areas, which are more structured with presence of macrophytes, showed the highest density and richness even in the Paraná River that has great human impact. We verified dominance of Americabaetis alphus, Tricorythopsis araponga, Tricorythopsis artigas on the Parana River, correlated with transparency, depth and electric conductivity, while the dominance of Traverella sp. was correlated with water temperature, especially in marginal areas. Consequently, the increasing transparency and electric conductivity due to the Porto Primavera dam in Parana River can be favoring those Ephemeroptera species. We demonstrated the importance of preserving the wetlands of Ivinhema River State Park mainly for Guajirolus sp., which was only registered in this region. Therefore, our study provides support for understanding gaps from previously studies using artificial substrates in three large rivers which are of great importance to the upper Paraná River floodplain.

Reservoir longitudinal gradient promotes ordered losses on diversity and density of Ephemeroptera community.

Reservoir operations alter, eliminate or restrain the natural hydrologic cycles. Biotic community has become subject to these non-cyclic events, responding by reducing the species diversity. Ephemeroptera species present distinct responses to environmental deterioration such that poses this assemblage between the most useful groups in biomonitoring programs. We hypothesized an alteration in beta diversity at the longitudinal species gradient, which will be influenced mainly by species losses between zones. Changes in temporal beta diversity is also expected, but the main drivers of such alterations will be the species turnover between the sampling period. Ephemeroptera community was monitored in nine sampling points from Itaipu Reservoir, where were installed three sets of substrates composed by a float and 2 wooden substrates. We took biological samples in triplicates monthly, from June-01 to August-02. Our initial hypothesis was partially supported and with significant variations only for spatial approach, between the Reservoir zones. The generated ordering from Non-Metric Dimensional Scale - NMDS - corroborated with spatial analyzes, with the formation of two groups along the gradient zonation of the reservoir. The temporal ordination showed no clear pattern. As expected, the contribution to beta diversity was different for our two approaches, such that the loss of species was more important along the spatial gradient and despite of no significant result, the species replacement was more important among months. The spatial results lead us to infer that differences in limnological characteristics between zones are important for determining differences in Ephemeroptera composition and can reflect the dependency degree of the species in relation to the lentic and sometimes-lotic conditions, mainly in the riverine zone of reservoirs. On the other hand, the absence of a temporal pattern can be result of chaotic variations in the physical and chemical attributes imposed by the reservoir operation, disrupting continuity of the biota and natural succession processes.

Pollen Ingestion by Chrysoperla externa (Hagen) Adults in a Diversified Organic Agroecosystem.

Chrysoperla externa (Hagen) larvae prey on pest insects and mites in agroecosystems, and adults mainly feed on pollen, nectar, and honeydew. Therefore, preserving this lacewing in crop systems depends on having plants that provide these resources. The objectives of this research were to identify pollen grains ingested by Ch. externa adults collected in a diversified organic agroecosystem and to evaluate whether there is a difference in the amount of ingested pollen grains between males and females. The adults of Ch. externa were collected in four different crops during 13 months in Seropédica, state of Rio de Janeiro, Brazil, using a collecting net. The adults were killed and underwent acetolysis, in order to recover the pollen in the gut. A total of 37,441 pollen grains from 19 Angiospermae families were found, besides 16 Pteridophyte spores. Among the recognized pollen grains, those of Poaceae were the majority, both in frequency of occurrence (87.5%) and in quantity (33496), and were found and recovered in every month of collection. Females and males ingested, respectively, 71.9 and 28.1% of the total number of Angiospermae pollen grains consumed by both sexes. The highest number of Poaceae pollens was obtained from the females (72.1% of the total number of Poaceae pollen, recovered from females + males). Taken as a whole, this study showed that adults of Ch. externa find possibilities to maintain throughout the year, in different crops, but the main source of pollen to males and females was Poaceae plants.

Immunome differences between porcine ileal and jejunal Peyer's patches revealed by global transcriptome sequencing of gut-associated lymphoid tissues.

The epithelium of the intestinal mucosa and the gut-associated lymphoid tissues (GALT) constitute an essential physical and immunological barrier against pathogens. In order to study the specificities of the GALT transcriptome in pigs, we compared the transcriptome profiles of jejunal and ileal Peyer's patches (PPs), mesenteric lymph nodes (MLNs) and peripheral blood (PB) of four male piglets by RNA-Seq. We identified 1,103 differentially expressed (DE) genes between ileal PPs (IPPs) and jejunal PPs (JPPs), and six times more DE genes between PPs and MLNs. The master regulator genes FOXP3, GATA3, STAT4, TBX21 and RORC were less expressed in IPPs compared to JPPs, whereas the transcription factor BCL6 was found more expressed in IPPs. In comparison between IPPs and JPPs, our analyses revealed predominant differential expression related to the differentiation of T cells into Th1, Th2, Th17 and iTreg in JPPs. Our results were consistent with previous reports regarding a higher T/B cells ratio in JPPs compared to IPPs. We found antisense transcription for respectively 24%, 22% and 14% of the transcripts detected in MLNs, PPs and PB, and significant positive correlations between PB and GALT transcriptomes. Allele-specific expression analyses revealed both shared and tissue-specific cis-genetic control of gene expression.

Sediment toxicity tests using the burrowing amphipod Tiburonella viscana (Amphipoda: Platyischnopidae).

The present study investigated the feasibility of the use of the burrowing amphipod Tiburonella viscana for sediment toxicity assessments. The effects of reference toxicants, salinity, sediment particle size, and sediment contamination on amphipod survival were analyzed. The sensitivity of T. viscana to zinc, chromium, and sodium dodecyl sulfate (SDS) in acute tests was similar to that of other crustaceans. The 48-h LC(50) (lethal concentration to 50% of the test organisms in a 48-h exposure) values for T. viscana (95% confidence intervals in parenthesis) were 0.79 (0.56-1.12), 5.85 (4.9-7.0), and 3.41 (2.87-4.04) mg L(-1) for zinc, chromium, and SDS, respectively. The species tolerated salinity as low as 19 ppt under laboratory conditions, indicating its suitability for use in tests with some estuarine sediments. The survival of T. viscana was not affected by grain size in field-collected sediments ranging from 60.6% silt and clay to 95.5% sand, but survival was significantly reduced in laboratory-sieved sediments containing only one or two particle sizes, e.g., only medium and coarse sand, or medium sand, or fine sand, or only fines, suggesting that a mixed grain size distribution is necessary for amphipod survival.

Temporal and spatial fluctuations of phytoplankton in a tropical coastal lagoon, southeast Brazil.

Spatial and temporal variability of the phytoplankton community in the tropical coastal Imboassica lagoon, an environment naturally isolated from the ocean by a narrow sandbar, was analysed every two weeks for 19 months by sampling three sites. During this study, the lagoon received direct input of marine water three times, resulting in remarkable salinity, nutrient concentrations and phytoplankton biomass variations in both temporal and spatial aspects. The phytoplankton biomass presented relatively low values ranging, on average, from 0.54 mg x L(-1) in the station closest to the sea (station 1) to 1.34 mg x L(-1) in the station close to a macrophyte bank (station 3). Diatoms and cryptomonads dominated in stations 1 and 2 (located relatively close to station 1, yet receiving the runoff of domestic sewage), and euglenoids, cryptomonads and dinoflagellates at station 3. Stations 1 and 2 usually presented the same dominant species but station 2 presented a higher phytoplankton biomass. On the other hand, station 3 showed more similar results concerning phytoplankton biomass with station 2, however the dominant species were usually different. The high fluctuations of salinity and the reduced nutrient availability are pointed out as the main factors structuring the dynamics of the phytoplankton community at the Imboassica lagoon.