Using CDOM spectral shape information to improve the estimation of DOC concentration in inland waters: A case study of Andean Patagonian Lakes.

For the last two decades different scientific disciplines have focused on lacustrine dissolved organic matter (DOM) given its importance in the biogeochemistry of carbon and in ecosystem functioning. New satellites supply the appropriate resolutions to evaluate chromophoric dissolved organic matter (CDOM) in inland waters, opening the possibility to estimate DOM at appropriate spatiotemporal scales. This requires, however, a robust relationship between CDOM and dissolved organic carbon (DOC). In this work, we evaluated the use of CDOM as a proxy of DOC in 7 Andean Patagonian lakes. Considering the entire data set, CDOM absorption coefficients (a355 and a440) were linearly related with DOC. Shallow lakes, however, drove this relationship showing a moderate relationship, whereas, deep lakes with lower colour presented a weaker relationship. Therefore, we assessed the use of CDOM spectral shape information to improve DOC estimates regardless of observed DOM differences due to climatic seasonality and lakes' morphometry. The use of well-known CDOM spectral shape metrics (i.e., S275-295 and a250:a365 ratio) significantly improved DOC estimation. Particularly, using a Gaussian decomposition approach we found that much of the variation in the spectral shape, associated with the variability of CDOM:DOC ratio, was explained by differences in two dynamic regions centred at 270 and 320 nm. A strong nonlinear relationship was found between the a270:a320 ratio and the DOC-specific absorption coefficients a*355 and a*440. This was translated into a further improvement in DOC estimation yielding the higher R2 and lower mean absolute differences (MAPD < 16%), either considering the entire data set or shallow and deep lakes separately. Our results highlight that incorporating the CDOM spectral shape information improves the characterization of the DOC pool of inland waters, which is particularly relevant for remote and/or inaccessible sites and has significant implications for the environmental management, biogeochemical studies and future remote sensing applications.

Fluorescence components of natural dissolved organic matter (DOM) from aquatic systems of an Andean Patagonian catchment: Applying different data restriction criteria for PARAFAC modelling.

Fluorescence spectroscopy is a widely applied technique to characterize the composition of the fluorescent fraction of dissolved organic matter (DOM), allowing to infer sources and diagenetic state of soil, marine and freshwater DOM samples. The analysis of fluorescent DOM (FDOM) is often carried out by multi-way models such as parallel factor analysis (PARAFAC), which allows decomposing excitation-emission matrices (EEMs) obtained from DOM samples into their underlying chemical components. Some aspects of the performance/accuracy of the EEM-PARAFAC technique regarding the use of selective vs. non-selective EEM data are still in discussion. In this investigation, we evaluated the outcome of two different approaches (non-selective and selective) applied to study the composition of DOM from four headwater streams (Case 1) and from two neighboring shallow lakes (Case 2), all belonging to the same Andean watershed within Nahuel Huapi National Park in North Patagonia (Argentina). In both cases, the outcome of the PARAFAC performed to non-selective data (EEM datasets from all the streams and the two lakes) vs. selective datasets (EEMs from each stream and each lake treated separately) is compared on the basis of modelled fluorescent components. Regardless of the restriction criteria applied for the analyses, the results obtained indicated similar component loadings in the four streams and in the two lakes. The similarity of the outcomes likely relates to the low internal variation of the EEMs, since these are located in the same catchment, influenced by similar soils and vegetation which are the main DOM sources. Therefore, we conclude that the use of a small selective EEM dataset may not condition the validation of the FDOM components and their temporal dynamics.

A high-resolution time-depth view of dimethylsulphide cycling in the surface sea.

Emission of the trace gas dimethylsulphide (DMS) from the ocean influences the chemical and optical properties of the atmosphere, and the olfactory landscape for foraging marine birds, turtles and mammals. DMS concentration has been seen to vary across seasons and latitudes with plankton taxonomy and activity, and following the seascape of ocean's physics. However, whether and how does it vary at the time scales of meteorology and day-night cycles is largely unknown. Here we used high-resolution measurements over time and depth within coherent water patches in the open sea to show that DMS concentration responded rapidly but resiliently to mesoscale meteorological perturbation. Further, it varied over diel cycles in conjunction with rhythmic photobiological indicators in phytoplankton. Combining data and modelling, we show that sunlight switches and tunes the balance between net biological production and abiotic losses. This is an outstanding example of how biological diel rhythms affect biogeochemical processes.

A novel immunocompetent murine model for replicating oncolytic adenoviral therapy.

Oncolytic adenoviruses are under investigation as a promising novel strategy for cancer immunotherapeutics. Unfortunately, there is no immunocompetent mouse cancer model to test oncolytic adenovirus because murine cancer cells are generally unable to produce infectious viral progeny from human adenoviruses. We find that the murine K-ras-induced lung adenocarcinoma cell line ADS-12 supports adenoviral infection and generates infectious viral progeny. ADS-12 cells express the coxsackie and adenovirus receptor and infected ADS-12 cells express the viral protein E1A. We find that our previously described oncolytic virus, adenovirus TAV-255 (AdTAV-255), kills ADS-12 cells in a dose- and time-dependent manner. We investigated ADS-12 cells as an in-vivo model system for replicating oncolytic adenoviruses. Subcutaneous injection of ADS-12 cells into immunocompetent 129 mice led to tumor formation in all injected mice. Intratumoral injection of AdTAV-255 in established tumors causes a significant reduction in tumor growth. This model system represents the first fully immunocompetent mouse model for cancer treatment with replicating oncolytic adenoviruses, and therefore will be useful to study the therapeutic effect of oncolytic adenoviruses in general and particularly immunostimulatory viruses designed to evoke an antitumor immune response.

Optical properties of highly turbid shallow lakes with contrasting turbidity origins: the ecological and water management implications.

A comprehensive optical study of three highly turbid shallow lakes was presented. The lakes contained very high concentrations of optically active substances [OASs] with clear differences in total suspended solid [TSS] composition among them. Lakes presented elevated values of total absorption [at(λ)] and scattering coefficients [b(λ)], which translated into extremely high light attenuation coefficients [Kd(PAR)]. Differences among lakes in the estimation of Kd(PAR), using two typical estimators of light penetration (i.e., nephelometric turbidity [Tn] and Secchi disk [ZSD]), were analysed. Kirk's optical model was used to model Kd(PAR) using inherent optical properties [IOPs]. Modelled values of Kd(PAR) agreed very well with those measured (R(2) = 0.95). In addition, optical properties and Kirk's model were used to determine water quality targets for restoring submerged aquatic vegetation [SAV]. Based on a minimum light requirement for SAV of 10%, results showed that only an integrative remediation action, considering substantial reduction of TSS and Chl a (95%), and CDOM (50%), must be contemplated to improve maximum colonization depth for SAV to values higher than 0.7 m. On the other hand, phytoplankton absorptive characteristics were also studied. In these lakes, phytoplankton showed different responses to the nature of light competition. Some of the variation in specific phytoplankton absorption [aph(*)(λ)] was explained by differences in the ratio between unpigmented particulate absorption and phytoplankton absorption (up to R(2) = 0.48 for the blue band). Hydrologic optical results were discussed in terms of ecological and management implications.

Effects of the herbicide Roundup on freshwater microbial communities: a mesocosm study.

The impact of the widely used herbicide glyphosate has been mainly studied in terrestrial weed control, laboratory bioassays, and field studies focusing on invertebrates, amphibians, and fishes. Despite the importance of phytoplankton and periphyton communities at the base of the aquatic food webs, fewer studies have investigated the effects of glyphosate on freshwater microbial assemblages. We assessed the effect of the commercial formulation Roundup using artificial earthen mesocosms. The herbicide was added at three doses: a control (without Roundup) and two treatments of 6 and 12 mg/L of the active ingredient (glyphosate). Estimates of the dissipation rate (k) were similar in the two treatments (half-lives of 5.77 and 7.37 d, respectively). The only two physicochemical parameters showing statistically significant differences between treatments and controls were the downward vertical spectral attenuation coefficient kd(lambda), where lambda is wavelength, and total phosphorus concentration (TP). At the end of the experiment, the treated mesocosms showed a significant increase in the ratio kd(490 nm)/k(d)(550 nm) and an eightfold increase in TP. Roundup affected the structure of phytoplankton and periphyton assemblages. Total micro- and nano-phytoplankton decreased in abundance in treated mesocosms. In contrast, the abundance of picocyanobacteria increased by a factor of about 40. Primary production also increased in treated mesocosms (roughly by a factor of two). Similar patterns were observed in the periphytic assemblages, which showed an increased proportion of dead: live individuals and increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in the microbial assemblages were captured by the analysis of the pigment composition of the phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical properties of the water. The observed changes in the structure of the microbial assemblages are more consistent with a direct toxicological effect of glyphosate rather than an indirect effect mediated by phosphorus enrichment.

Planktonic ciliates from an oligotrophic south Andean lake, Morenito Lake (Patagonia, Argentina).

In this contribution we have studied the planktonic ciliates from Morenito Lake, an oligotrophic lake situated in the South Andes of Argentina. Six species that are new records for South America or Argentina are described and illustrated. Besides, population dynamics of the ciliate species were studied during a spring-summer period. Strobilidium lacustris and Balanion planctonicum were the most abundant species, showing a maximum in mid summer. Paradileptus elephantinus was present all over the period while Urotricha furcata was observed in late summer samples. Strobilidium lacustris and S. humile were found to be occasional species during the studied period. The recorded ciliate assemblage with oligotrichs and prostomates as dominant indicate the oligotrophic condition of the lake.

Planktonic ciliates from an oligotrophic South Andean lake, Morenito Lake (Patagonia, Argentina)

In this contribution we have studied the planktonic ciliates from Morenito Lake, an oligotrophic lake situated in the South Andes of Argentina. Six species that are new records for South America or Argentina are described and illustrated. Besides, population dynamics of the ciliate species were studied during a spring--summer period. Strobilidium lacustris and Balanion planctonicum were the most abundant species, showing a maximum in mid summer. Paradileptus elephantinus was present all over the period while Urotricha furcata was observed in late summer samples. Strobilidium lacustris and S. humile were found to be occasional species during the studied period. The recorded ciliate assemblage with oligotrichs and prostomates as dominant indicate the oligotrophic condition of the lake

Cloning and molecular characterization of the cDNA for the Brazilian larval click-beetle Pyrearinus termitilluminans luciferase.

The larval click-beetle Pyrearinus termitilluminans elicits the phenomenon of luminous termite mounds in the central-west region of Brazil. The bioluminescence (BL) spectrum of this larva (lambda max = 534 nm) is one of the most blue-shifted reported among known luminescent Coleoptera. We have isolated mRNA from larval thoracic lanterns and constructed a cDNA library into a lambda ZAP II vector. An expression library was obtained after excision of the pBluescript plasmid. This library was screened by photodetection and one clone that emitted green BL (lambda max = 538 nm) was isolated. The 2.2 kb cDNA insert includes a 543 residue open reading frame showing 82% homology with the luciferase isoenzymes of Pyrophorus plagiophthalamus (Coleoptera: Elateridae). As expected, the region between residues 223 and 247 that contains the putative active site for BL color determination showed a higher degree of homology among click-beetle luciferases that elicit closer BL colors. The in vitro BL spectrum of recombinant P. termitilluminans luciferase also peaks at 538 nm and, as in the case of native enzyme, does not show any bathochromic shift upon decreasing the pH.

Natural history of squamous cell carcinoma of the skin: case report.

Squamous cell carcinoma is a malignant proliferation of the epidermal keratinocyte. With early recognition and treatment, most of these tumors have a favorable prognosis. If the lesions are left untreated, however, the results may prove fatal. We describe a case of long-standing neglect of cutaneous squamous cell carcinoma leading to widely metastatic disease in a 69-year-old man.

Mast cells, neutrophils, and eosinophils in prurigo nodularis.

BACKGROUND AND DESIGN: Prurigo nodularis is a disease of unknown cause. To characterize the involvement of mast cells, neutrophils, and eosinophils in lesional tissue, we analyzed seven skin biopsy specimens by an indirect immunofluorescence technique for localization of mast cell tryptase, neutrophil elastase, and eosinophil granule major basic protein, eosinophil cationic protein, and eosinophil-derived neurotoxin. RESULTS: Mast cells were detected in all of the specimens, with prominent numbers of mast cells in three specimens; there was minimal or no extracellular deposition of tryptase in any of the tissues. Neutrophil infiltration was observed in all specimens, but few cells were observed in four; extracellular elastase was minimal or absent in all but one specimen in which prominent dermal elastase deposition was found. Scanty eosinophil infiltration was present in all specimens; however, extracellular deposition of the eosinophil granule proteins including major basic protein, eosinophil-derived neurotoxin, and eosinophil cationic protein was present in all but one specimen and striking deposition of at least one eosinophil granule protein was present in six of the seven specimens. CONCLUSIONS: These studies suggest that mast cell numbers are increased in prurigo nodularis and that eosinophil degranulation as evidenced by striking extracellular deposition of granule proteins is prominent in lesions. In contrast, extracellular deposition of mast cell and neutrophil proteins is absent. The distinctive proteins of the eosinophil granule have potent effects on tissues; the toxicity of these proteins and their deposition in lesional tissue suggest a pathogenic role for the eosinophil in prurigo nodularis.

Abnormal left ventricular contraction revealed by impedance cardiograms and arterial tracings in bundle branch blocks and old myocardial infarcts.

Following the observation of an unusual pattern of the first derivative of the impedance cardiogram in cases of bundle branch block, a systematic study was performed both in normal controls and clinical cases. This graphic study was supplemented by the simultaneous recording of the first derivative of an arterial tracing, preferably the indirect aortic pulse at the suprasternal notch. These studies were performed in 70 subjects: 30 normal subjects, 14 cases of right bundle branch block, 14 cases of left bundle branch block, and 12 cases of old infarcts. Out of 30 normal subjects, only 2 old persons showed splintering of the main systolic wave. Both right and left bundle branch blocks had in common either a splitting of this wave in 2 peaks or multiple splintering; however, 4 cases in each type of bundle branch block had a normal pattern. Among old infarcts, 7 had a splitting, 3 had multiple splitting, and 2 had a normal pattern. The derivative of the arterial tracings showed a remarkable similarity with that of the impedance cardiogram, revealing that abnormal left ventricular ejection (dyssynergy) was present in all 3 types of lesion. The first derivative of the impedance cardiogram was often more typical than that of the arterial tracings, because it had fewer secondary vibrations or artifacts. Thus, the former seems more sensitive to diagnosing left ventricular abnormalities of contraction, even when the electrocardiogram is normal.

[The high frequency components of the heart sounds in normal subjects (author's transl)]. / Le componenti ad alta frequenza dei toni cardiaci nei soggetti normali

A technical set up for recording high frequency components of the cardiac vibrations is described. This was based on the use of several amplifiers, taking the third derivative of the displacement tracing, and using a high pass filter with a sharp slope. The tape-recorded high frequency tracing, at 500 Hz, 1000 Hz, or higher, was replayed at slower speed for accurate recording of the high speed signals. A study of the first and second hearts sound at 500 Hz and 1000 Hz was made in 14 young, normal volunteers. The high frequency vibrations of these sounds are analyzed and discussed.

When does a fourth sound become an atrial gallop?

A study of the fourth sound was conducted on 100 normal subjects (ages 1-88 years) and 42 clinical cases with either aortic stenosis, systemic hypertension or coronary heart disease. This study was based on the graphic recognition of a presystolic sound when the tracing was taken with the use of one or more of 5 different high pass filters. Attention was paid to the existence of the fourth sound, its magnitude, and its vibrational frequency. In general it was accepted that a magnitude of 1/2 of the first heart sound or a frequency of 30 Hz denoted a pathologic fourth sound. However, exceptions were found among normal subjects, so that only the combination of the two criteria could be considered highly significant for a pathologic phenomenon (gallop). Patients with aortic stenosis presented an increase in magnitude of the fourth sound but incidence and vibrational frequency were similar to those of controls. Patients with hypertension had a greater incidence of fourth sounds, especially in middle age (100%); middle age patients usually had a greater magnitude while older patients had more often an increase in vibrational frequency. Patients with coronary heart disease (evidence of old infarcts) had an increase in the incidence, magnitude, and vibrational frequency in comparison with controls. These data and the cause of the fourth sound are discussed. The fourth sound has been repeatedly studied in the past, both as an auscultatory finding and a graphic phenomenon. Attempts were made for separating the normal fourth sound from that denoting a pathological phenomenon but, so far, no clear cut criteria for the differentiation have been obtained. We thought, therefore, that a new study was indicated.

Incidence of murmurs in the aging heart.

One hundred patients aged 60 or older were studied clinically after excluding those with cardiac enlargement, definite valvular lesions or electrocardiographic (ECG) evidence of left ventricular hypertrophy. In 30 of the the 100 patients a significant systolic murmur was heard on auscultation. Phonocardiograms (PCGs), mitral echograms and pulse tracings were obtained in 28 of these 30 patients (2 had died meanwhile), and the ECGs and chest roentgenograms were reviewed. In 23 PCG patients there was an early or midsystolic murmur, best recorded at the base of the heart and often transmiteed to the apex. Mitral valve echograms and carotid and jugular pulse tracings were normal in all cases. Chest roentgenograms revealed aortic enlargement in 83 percent of the 23 patients. In the elderly with no evidence of organic heart disease, a basal systolic murmur is probably an aortic flow phenomenon caused by either moderate aortic dilatation or minimal fibrotic fusion of one or more commissures of the aortic valve.