João Paulo Cabral

Water Microbiology. Bacterial Pathogens and Water

Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

Can we use indoor fungi as bioindicators of indoor air quality? Historical perspectives and open questions

Microbiological analysis of atmospheres witnessed substantial technical improvements in the 1940s to 1960s. Mays cascade impactor and Hirsts spore trap allowed the counting of total cells but had limited capacity for identification of the spores. Bourdillons sampler enabled the counting of cultivable fungi and their identification. A great step forward was given with the Andersens six-stage impactor, which allowed discrimination of particles by size, counting of cultivable cells, and species identification. This period also witnessed the development of impingers, namely, the AGI-30 described by Malligo and Idoine, and the three-stage model designed by K. R. May. The 1990s to 2000s witnessed innovative discoveries on the biology of indoor fungi. Work carried out in several laboratories showed that indoor fungi can release groups of spores, individual spores and fungal fragments, and produce volatile organic compounds and mycotoxins. Integrating all findings a holistic interpretation emerged for the sick building syndrome. Healthy houses and buildings, with low indoor humidity, display no appreciable indoor fungal growth, and outdoor Cladosporium dominates. On the contrary, in sick houses and buildings, high indoor humidity allows fungal growth (mainly of Penicillium and Aspergillus), with concomitant release of conidia and fragments into the atmosphere. The intoxication probably results from a chronic exposure to volatile organic compounds and mycotoxins produced by Penicillium, Aspergillus, and Stachybotrys. Very clean atmospheres are difficult to study by conventional methods. However, some of these atmospheres, namely, those of hospital rooms, should be monitored. Sedimentary sampling, chemical methods applied to impingers collection liquid, and selected molecular methods can be useful in this context. It was concluded that fungi can be useful indicators of indoor air quality and that it is important to deepen the studies of indoor atmospheres in order to promote air quality, the health and well-being of all, and a better understanding of the biology of indoor fungi.

Biomonitoring with benthic macroalgae and direct assay of heavy metals in seawater of the Oporto coast (Northwest Portugal)

The concentrations of dissolved Cd, Cu, Hg and Pb in seawater and algae (Enteromorpha spp. and Porphyra spp.) were determined in parallel on three beaches located in the Oporto coast (Portugal), during 8 successive months, comprising periods of low and high biological productivity. The concentrations of dissolved metals in seawater varied markedly during the sampling period and exhibited seasonality. The concentrations of Cd were high in autumn and winter, but low in spring. The concentrations of Cu and Hg were high in autumn, low in winter and peaked in May. The concentrations of Pb were low in autumn and winter, and also peaked in May. It is likely that biological activity was, at least partially, responsible for the observed seasonal changes. The mean concentrations of dissolved metals in seawater were similar to those reported for polluted and industrialized european coastal areas. Metal concentration factors, calculated month-to-month for each alga, metal and site, varied markedly during the sampling period, indicating that concentration factors based on single or few determinations could be misleading. On the contrary, mean concentration factors (calculated by dividing the mean metal concentration in the algae by the mean metal concentration in seawater) were relatively constant at all three sites, indicating that in the Oporto coast, Enteromorpha spp. can be used to estimate the mean concentration of dissolved Cd, Cu and Hg in seawater, and Porphyra spp., the mean concentration of Cd, Cu and Pb. However, considering that future estimates of the concentrations of these metals in seawater should be based on determinations of the metal contents in Enteromorpha spp. and Porphyra spp. carried out on several occasions spanning a considerable period of time, the use of these algae as monitors of heavy metal pollution can have limited practical advantages over the direct assay of the metals in seawater.

«Phaeoacremonium chlamydosporum» and « Phaeoacremonium angustius» Associated with Esca and Grapevine Decline in «Vinho Verde» Grapevines in Northwes Portugal

Vinho Verde is a unique wine, exclusively produced in the northwest region of Portugal. The production of this wine is an important component of portuguese agriculture. The aims of the present work were to make a preliminary assessment of the presence of esca and grapevine decline in the Vinho Verde region, and to check for the presence of Phaeoacremonium spp. in diseased plants. The results showed that esca and grapevine decline do occur in the Vinho Verde region, and can be widespread in this region. From ten diseased grapevines we isolated nine strains of P. chlamydosporum, and one strain as P. angustius. Our results agree with other reports that P. chlamydosporum is frequently isolated from the wood of grapevines showing symptoms of esca or grapevine decline. P. aleophilum and P. inflatipes were not isolated from the plants examined in the present study. Instead, P. angustius was isolated from a diseased plant.

Copper toxicity to five Parmelia lichens in vitro

Abstract Treatment of Parmelia caperata , P. perlata , P. subrudecta , P. sulcata and P. tiliacea with CuSO 4 resulted in a time- and copper-concentration-dependent decrease in the total and intracellular potassium concentrations of the thallus, indicating that copper damaged the cytoplasmic membrane. Treatment with copper also resulted in a time-dependent increase in the total copper concentration of the thallus. After 4 h of exposure to copper, the process of potassium efflux was essentially completed but the absorption of copper was still increasing; moreover, the amount of copper bound to the thallus exceeded twice the amount of potassium released from the thallus, suggesting that cupric ions reached intracellular sites in the thallus, and K + /Cu 2+ exchange was not electroneutral. After 5 h of exposure to copper, the extent of decrease in the total and intracellular potassium concentrations of the thallus was positively correlated with copper absorption levels, but only at 0.05 P 2+ concentration revealed the presence of copper-binding ligands, and several successive absorption cycles, most probably corresponding to the binding of Cu 2+ to each of the lichen substances detected in the extracts. However, no significant correlation ( P >0.10) was found between the Cu 2+ -complexing capacity of acetone extracts and copper-induced membrane damage. It was concluded that in the studied Parmelia species, and in the experimental conditions used in this work, copper toxicity was not a simple function of the Cu 2+ -binding properties of the lichen substances present in the thallus. Several hypotheses were formulated to interpret the results.

Morphometric analysis of limpets from an Iron-Age shell midden found in northwest Portugal

The present work reports an analysis of a shell midden found in Terroso hillfort, an important Iron-Age oppidum located in northwest Portugal. The midden was dated from the latest phase of occupation of the hillfort, between the Ist century BC and the Ist century AD (Roman period), and contained 684 well-preserved Patella shells. The identification of archaeological shells was carried out comparing them with modern specimens collected in two shores in the neighborhood of the hillfort. The identification of modern shells was based on radula pluricuspid teeth and shell morphology. Relative abundance of Patella species in the Terroso midden was different from modern populations. Archaeological shells were dominated by Patella vulgata, but Patella intermedia was the most abundant species in modern populations. Dimensions of archaeological shells were very different from modern populations. Shell length range and variability in archaeological shells were lower than in the modern populations. Log height vs. length plots for archaeological shells were different from modern populations. Patella shells from Terroso midden was significantly taller then modern specimens. These differences between archaeological shells and modern populations could be due to environmental changes, namely an increase in wave action and intensity. These harsher costal conditions could have resulted from an alteration in the morphology of the coast, caused by a rise in the mean sea level from 2000 years BP to the present. Alternatively or additionally, the observed differences can be related to gathering strategies. Archaeological shells could have been selected by size, and collected preferentially at high shore and in sheltered sites.

Damage to the cytoplasmic membrane and cell death caused by dodine (dodecylguanidine monoacetate) in Pseudomonas syringae ATCC 12271.

Treatment of Pseudomonas syringae cells with low concentrations of the fungicide dodecylguanidine monoacetate (dodine) resulted in cell death and leakage of K+, UV-absorbing materials, and ribose-containing molecules. The results suggest that dodine causes gross and extensive damage to the cytoplasmic membrane, which is probably implicated in the death of cells.

Determination of the critical micelle concentration of dodecylguanidine monoacetate (dodine)

Abstract Critical micelle concentrations (CMCs) of dodecylguanidine monoacetate (dodine) were determined at 22.5°C by UV spectroscopy and from measurements of dye complexation, surface tension, and capillary rise. Over the range 5–260 μ M dodine, two discontinuities were found in the relationship between the physical parameter of the solution and dodine concentration. It is proposed that the two discontinuities corresponded to the CMC I and CMC II . Depending on the method of determination, the CMC I of dodine fell within the range 16–31 μ M , and that of the CMC II within the range 110–120 μ M . In comparison with other detergents of similar molecular structure, dodine displayed an extremely low CMC I .

Fungal Air Quality in Medical Protected Environments

Fungi are ubiquitous in indoor environments and are responsible for a wide range of diseases, from localized non-invasive pathologies to invasive and disseminated infections. These infections occur predominantly among highly immunosuppressed patients (patients with acute leukaemia, haematopoietic stem cell or solid organ transplantation) and can have devastating consequences. Aspergillus remains the most common mould to cause invasive infections, but other fungi are emerging as serious pathogens and threats in immunosuppressed patients. Most invasive fungal infections are acquired from air. It is therefore imperative to adopt, in clinical environments, preventive measures in order to reduce airborne fungal concentrations and, concomitantly, the risk for development of a fungal infection. At present, there are no methods and equipments that can completely eliminate fungi from indoor medical environments. Exposure to moulds in medical units is inevitable but the presence of air filtration systems, isolation, and adoption of environmental protective measures do mitigate patient exposure. Airborne mycological investigations should inform about indoor air quality and therefore should be routinely carried out in hospitals or other institutions where immunosuppressed individuals are treated. It is important to improve the methods already available to study indoor fungi in clean environments, and it is critical to define indicators of indoor air quality in medical environments. The present chapter deals with the biology of indoor fungi in medical environments, and the strategies and technical progresses that are at present available to prevent and control fungal diseases and to improve air quality in medical facilities.

The ability of biological and organic synthetic materials to accumulate atmospheric particulates containing copper, lead, nickel and strontium

This work was aimed at finding materials that could be used as alternatives to lichens as air quality monitors since the high natural variability and the large amount of lichen collected are two drawbacks of the use of these organisms. Lichen Flavoparmelia caperata(L.) Hale was exposed in three different forms (transplant, detached from the substratum and as a biomass-ground and homogeneized) and compared to the planetree bark (Platanus hybrida Brot.), exposed as a biomass, and two organic synthetic materials (Chelex(R) 100 resin and cellulose acetate). Materials were exposed for two months in the winter, spring and summer, at three Portuguese coastal cities. The results showed that the airborne accumulations of Cu, Ni, Pb and Sr were partially dependent on the meteorological conditions but mainly dependent on the nature of the exposed material. The standard deviations of the synthetic materials or homogenized biomass were the same or greater than lichen transplants or detached. The accumulation by biological materials, of the four studied elements, was comparable to the lichen transplant accumulation. The replacement of the traditional transplants by the biomass was not considered advantageous, since their preparation is time-consuming. Therefore lichens remain the most suitable in biomonitoring studies. The exposure of detached lichen allows the accurate measurement of the exposed area/volume so it can be useful to relate atmospheric deposition rates with the lichen metal content. The synthetic materials accumulated Cu and Ni and should only be used as an alternative to traditional transplants when these are the elements of interest.