Virus decomposition provides an important contribution to benthic deep-sea ecosystem functioning

Virus decomposition provides an important contribution to benthic deep-sea ecosystem functionin

Spontaneous Cholecystocutaneous Fistula

Spontaneous cholecystocutaneous fistula is a rare complication of chronic calculous cholecystitis because currently gallstones are diagnosed and treated at an early stage. This occurrence is possible even if it seems actually to be rare. We report the case of a 90-year-old woman admitted to our hospital with diarrhea of 4 days duration and low-grade fever (37.5°C). On physical examination, she had a 10 × 10 cm erythematous swelling and discomfort of the upper right abdominal quadrant; the skin and mucosae were dry. Transabdominal ultrasonography showed a gallbladder with abnormalities of the wall, a single gallstone impacted in the infundibulum and a fluid collection with irregular margins containing fluctuating echoes adjacent to the anterior abdominal wall of the upper right abdominal quadrant. A diagnosis of spontaneous cholecystocutaneous fistula with an abdominal purulent collection was reached. Due to the high anesthesiological risk of the patient, conservative management was carried out with fluids, broad-spectrum antibiotic, albumin and calcium supplementation. Computed tomography drainage of the purulent collection was also carried out. Both clinical and laboratory parameters substantially improved during the following two days, but on the third day of hospitalization, the patient died from a sudden arrhythmic event

Diversity and spatial distribution of metalreducing bacterial assemblages in groundwaters of different redox conditions

The spatial distribution and diversity of metal-reducing bacterial assemblages belonging to Geobacteraceae were studied in groundwaters with different physicochemical characteristics by means of terminal-restriction fragment length polymorphism (T-RFLP) molecular fingerprinting, as applied to the 16S rRNA gene. The physicochemical conditions of these environments were unfavorable to support active-metal-reducing processes. The highest diversity of Geobacteraceae was observed in groundwater samples characterized by the highest dissolved Fe and Mn concentrations. T-RFLP analyses revealed major differences in the Geobacteraceae ribotype diversity and community composition of the groundwater samples as well as a considerable variability and spatial turnover of Geobacteraceae assemblages. Results from this work suggest that changes in the physicochemical characteristics of the aquifer deeply influence the richness and community structure of Geobacteraceae, even in those systems in which metal-reduction processes are not dominant. [Int Microbiol 2009; 12(3):153-159

Rapid response of benthic deep-sea microbes (viruses and prokaryotes) to an intense dense shelf water cascading event in a submarine canyon of the NW Mediterranean Sea

A major dense shelf water cascading (DSWC) event occurred in 2005 downward the Cap de Creus Canyon (Gulf of Lion, NW Mediterranean Sea), which caused a significant change in environmental parameters and biological components. Here we describe the effects of this DSWC event on benthic microbes and on virus-prokaryote interactions, and we explore their implications on the functioning of the canyon's ecosystem. We collected sediment samples at increasing depths inside the canyon and in the adjacent deep continental margin over a period of five years, i.e. during and after the DSWC event, which led to the deposition of high amounts of fresh and labile organic matter that stimulated C production by benthic prokaryotes and increased their abundance and biomass. The enhanced prokaryotic metabolism, still evident 6 months after the DSWC event, was associated with high viral replication rates and prokaryotic mortality, which released 3.4-6.3 gC m−2 over such a 6 months period. Such values are up to 3-times higher than the yearly C-flux to the seafloor reported in this area in years without DSWC. We conclude that DSWC can significantly enhance benthic prokaryotic metabolism and C cycling through viral-induced prokaryotic mortality

Combining passive and active restoration to rehabilitate a historically polluted marine site

IntroductionPassive and active restoration approaches have been often considered as different alternatives to achieve the ecological restoration of a degraded site. This false dichotomy has been overcome in terrestrial ecosystems, for which a range of restoration approaches have often been applied within the same restoration project, creating a continuum of interventions. In the marine environment, the combined approach based on passive and active restoration is less studied.MethodsHere, we tested the possibility of actively restoring a macroalgal population in a historically polluted industrial site, subjected to decadal passive restoration (i.e., unassisted, or spontaneous recovery following cessation of industrial activity), in the Mediterranean Sea. Recently, it has been demonstrated that in the site under scrutiny, there is no longer any sign of the historical contamination or impact on benthic fauna therefore the environmental conditions are indistinguishable from surrounding non-impacted areas. We used artificial breakwater barriers already present in the site to restore a population of the brown algae Gongolaria barbata. The intervention was conducted by applying an in situ recruitment approach and a complementary action using cages to exclude the herbivores. The G. barbata recruits were transplanted on the artificial reefs and after they reached the maximum growth inside the cages, one cage was opened and another one was completely removed to also test the grazing pressure. The associated benthic assemblages were also analysed in terms of meio- and macrofaunal abundance, the richness of taxa, and taxonomic composition.Results and discussionOur results indicate that, at least over a relatively short period (i.e., 6 months), the use of the cages represents a useful tool to let the macroalgae grow enough to counterbalance the herbivory pressure. The associated fauna below the macroalgae was characterized by a different taxonomic composition when compared to controls (i.e., artificial reefs without the macroalgae), particularly when considered the rare taxa. In conclusion, the combination of passive and active restoration can be considered a useful approach to restore marine sites degraded by historical industrial activities

Paraganglioma of the cauda equina region

BACKGROUND CONTEXT: Cauda equina paragangliomas (CEPs) are rare neuroendocrine tumors. The difficulty in differential diagnosis with other tumors of this region may be misleading for surgical planning and prognostic expectations. PURPOSE: To report on a rare case of CEP and review the most current information regarding the diagnosis, treatment options, and outcomes. STUDY DESIGN: Case report and literature review. PATIENT SAMPLE: One patient affected by CEP. METHODS: We report on a 33-year-old woman with a 2-month history of worsening low back pain, aggravated by sitting, bending, and coughing. Neurological examination revealed normal power and muscular tone, no sensory or sphincter abnormality, and normal reflex. Magnetic resonance imaging of the lumbar spine demonstrated an intradural extramedullary lesion at L3, with homogeneous contrast enhancement and hypointense punctate foci. The patient underwent an L3 laminectomy and tumor removal. Relevant articles covering CEPs from 1970 to the present were reviewed. RESULTS: The histopathological examinations described paraganglioma features. The postoperative coursewas uneventful, and all the symptoms resolved, with no tumor recurrence after 3 years’ follow-up. CONCLUSIONS: Cauda equina paragangliomas are rare, benign, and slow-growing tumors. Except for its secreting tumor characteristics, preoperative CEP diagnosis is very difficult.Magnetic resonance imaging is important andmay suggest specific radiological features for these tumors; however, these are only relative, and it is rare that diagnosis ismade before surgery.Diagnosis is established by histological examination and electron microscopy, and immunohistochemical techniques must be used to achieve a correct diagnosis. Cauda equina paragangliomas arewell-encapsulated tumors that may be cured by surgery alone, whereas radiotherapy is reserved for incompletely resected tumors. Overall, prolonged postoperative observation is mandatory because of the slow tumor evolution and the possibility of tumor relapse even up to 30 years after surgery

Quantification of viral and prokaryotic production rates in benthic ecosystems:a methods comparison

Viruses profoundly influence benthic marine ecosystems by infecting and subsequently killing their prokaryotic hosts, thereby impacting the cycling of carbon and nutrients. Previously conducted studies, based on different methodologies, have provided widely differing estimates of the relevance of viruses on benthic prokaryotes. There has been no attempt so far to compare these independent approaches, including contextual comparisons among different approaches for sample manipulation (i.e., dilution or not of the sediments during incubations), between methods based on epifluorescence microscopy (EFM) or radiotracers, and between the use of different radiotracers. Therefore, it has been difficult to identify the most suitable methodologies and protocols to be used as standard approaches for the quantification of viral infections of prokaryotes. Here, we compared for the first time different methods for determining viral and prokaryotic production rates in marine sediments collected at two benthic sites, differing in depth and environmental conditions. We used a highly replicated experimental design, testing the potential biases associated to the incubation of sediments as diluted or undiluted. In parallel, we also compared EFM counts with the (3)H-thymidine incubations for the determination of viral production rates, and the use of (3)H-thymidine versus (3)H-leucine radiotracers for the determination of prokaryotic production. We show here that, independent from sediment dilution, EFM-based values of viral production ranged from 1.4 to 4.6 × 10(7) viruses g(-1) h(-1), and were similar but overall less variable compared to those obtained by the (3)H-thymidine method (0.3 to 9.0 × 10(7) viruses g(-1)h(-1)). In addition, the prokaryotic production rates were not affected by sediment dilution, and the use of different radiotracers provided very consistent estimates (10.3–35.1 and 9.3–34.6 ngC g(-1)h(-1) using the (3)H-thymidine or (3)H-leucine method, respectively). These results indicated that viral lysis was responsible for the abatement of 55–81% of the prokaryotic heterotrophic production, corroborating previous findings of the major role of viruses in benthic deep-sea ecosystems. Moreover, our methodological comparison for the analysis of viral production in marine sediments suggests that microscopy-based approaches are simpler and more cost-effective than those based on radiotracers. These approaches also reduce time to results and overcome issues related to generation of radioactive waste

Impact of CO2 leakage from sub-seabed carbon dioxide capture and storage (CCS) reservoirs on benthic virus-prokaryote interactions and functions

Atmospheric CO2 emissions are a global concern due to their predicted impact on biodiversity, ecosystems functioning, and human life. Among the proposed mitigation strategies, CO2 capture and storage, primarily the injection of CO2 into marine deep geological formations has been suggested as a technically practical option for reducing emissions. However, concerns have been raised that possible leakage from such storagesites, and the associated elevated levels of pCO2 could locally impact the biodiversity and biogeochemical processes in the sediments above these reservoirs. Whilst a number of impact assessment studies have been conducted, no information is available on the specific responses of viruses and virus host interactions. In the present study, we tested the impact of a simulated CO2 leakage on the benthic microbial assemblages, with specific focus on microbial activity and virus-induced prokaryotic mortality VIPM). We found that exposure to levels of CO2 in the overlying seawater from 1,000 to 20,000 ppm for a period up to 140 days, resulted in a marked decrease in heterotrophic carbon production and organic matter degradation rates in the sediments, associated with lower rates of VIPM, and a progressive accumulation of sedimentary organic matter with increasing CO2 concentrations. These results suggest that the increase in seawater pCO2 levels that may result from CO2 leakage, can severely reduce the rates of microbial-mediated recycling of these dimentary organic matter and viralin fections, with major consequences on C cycling and nutrient regeneration, and hence on the functioning of benthic ecosystems.publishedVersio

The challenge of proving the existence of metazoan life in permanently anoxic deep-sea sediments

The demonstration of the existence of metazoan life in absence of free oxygen is one of the most fascinating and difficult challenges in biology. Danovaro et al. (2010) discovered three new species of the Phylum Loricifera, living in the anoxic sediments of the L’Atalante, a deep-hypersaline anoxic basin of the Mediterranean Sea. Multiple and independent analyses based on staining, incorporation of radio labeled substrates, CellTracker Green incorporation experiments and ultra-structure analyses, allowed Danovaro et al. (2010) to conclude that these animals were able to spend their entire life cycle under anoxic conditions. Bernhard et al. (2015) investigated the same basin. Due to technical difficulties in sampling operations, they could not collect samples from the permanently anoxic sediment, and sampled only the redoxcline portion of the L’Atalante basin. They found ten individuals of Loricifera and provided alternative interpretations of the results of Danovaro et al. (2010). Here we analyze these interpretations, and present additional evidence indicating that the Loricifera encountered in the anoxic basin L’Atalante were actually alive at the time of sampling. We also discuss the reliability of different methodologies and approaches in providing evidence of metazoans living in anoxic conditions, paving the way for future investigation