Perception of Risks from Electromagnetic Fields: Lessons for the Future

Technologies based on extremely highfrequency electromagnetic fields, inparticular in the terahertz region, arequite recent and new to the public. While anumber of advantages have been shown,especially in the biomedical area,biological effects and possible healthimplications have not been fullyinvestigated. The experience gained withelectromagnetic fields of lowerfrequencies, from ELF to microwaves,suggests that innovating technologies maycreate concern, or even fear, among thepublic for hypothetical health risks.Social research has shown that worries arerelated to the perception of risks by thepublic more than to their actual existence.Risk perception depends on several factors,many of which are relevant forelectromagnetic fields. They include lackof familiarity with the agent, difficultyin understanding interaction mechanisms,and uncertainty in scientific knowledge.Lessons learnt from the past lead torecommend that specific research onbiological effects of terahertz radiationbe started from the very beginning of thedevelopment of technological applicationsand that a continuous and effectivedialogue be established between thescientific community and the public.     

Sensory Perception: An Overlooked Target of Occupational Exposure to Metals

The effect of exposure to industrial metals on sensory perception of workers has received only modest interest from the medical community to date. Nevertheless, some experimental and epidemiological data exist showing that industrial metals can affect vision, hearing and olfactory function, and a similar effect is also suggested for touch and taste. In this review the main industrial metals involved are discussed. An important limit in available knowledge is that, to date, the number of chemicals studied is relatively small. Another is that the large majority of the studies have evaluated the effect of a single chemical on a single sense. As an example, we know that mercury can impair hearing, smell, taste, touch and also vision, but we have scant idea if, in the same worker, a relation exists between impairments in different senses, or if impairments are independent. Moreover, workers are frequently exposed to different chemicals; a few available results suggest that a co-exposure may have no effect, or result in both an increase and a decrease of the effect, as observed for hearing loss, but this aspect certainly deserves much more study. As a conclusion, exposure to industrial metals can affect sensory perception, but knowledge of this effect is yet incomplete, and is largely inadequate especially for an estimation of “safe” thresholds of exposure. These data support the desirability of further good quality studies in this field.     

The Challenge of Antibiotic-Resistant Staphylococcus: Lessons from Hospital Nurseries in the mid-20th Century

In the late 1940s, epidemics of antibiotic-resistant strains of Staphylococcus aureus began to plague postpartum nurseries in hospitals across the United States. Exacerbated by overcrowding and nursing shortages, resistant S. aureus outbreaks posed a novel challenge to physicians and nurses heavily reliant on antibiotics as both prophylaxis and treatment. This paper explores the investigation of the reservoir, mode of transmission, and virulence of S. aureus during major hospital outbreaks and the subsequent implementation of novel infection control measures from the late 1940s through the early 1960s. The exploration of these measures reveals a shift in infection control policy as hospitals, faced with the failure of antibiotics to slow S. aureus outbreaks, implemented laboratory culture routines, modified nursery structure and layout, and altered nursing staff procedures to counter various forms of S. aureus transmission. Showcasing the need for widespread epidemiologic surveillance, ultimately manifesting itself in specialized “hospital epidemiology” training promoted in the 1970s, the challenges faced by hospital nurses in the 1950s prove highly relevant to the continued struggle with methicillin-resistant Staphylococcus aureus (MRSA) and other resistant nosocomial infections.     

Binding Specificity of Hydrolytic Catalytic Antibody: Lessons from the Diverse Immune System

The diverse immune system has the potential to provide numerous antibodies that catalyze a great variety of reactions and exhibit diversity in mechanism and substrate specificity. However, to find such an antibody is not practical, unless we understand the immune response precisely and utilize it. We applied an alternative screening methodology based on the binding specificity of antibodies for the structure of the transition-state analog p-nitrophenyl phosphonate in order to study the built-in diversity of the immune response. This study uncovered the unpredictable binding and substrate specificity of catalytic antibodies derived from the diverse immune response.     

Insights to the evolution of Nucleobase-Ascorbate Transporters (NAT/NCS2 family) from the Cys-scanning analysis of xanthine permease XanQ

The nucleobase-ascorbate transporter or nucleobase-cation symporter-2 (NAT/NCS2)family is one of the five known families of transporters that use nucleobases astheir principal substrates and the only one that is evolutionarily conserved andwidespread in all major taxa of organisms. The family is a typical paradigm of agroup of related transporters for which conservation in sequence and overallstructure correlates with high functional variations between homologs.Strikingly, the human homologs fail to recognize nucleobases or relatedcytotoxic compounds. This fact allows important biomedical perspectives fortranslation of structure-function knowledge on this family to the rationaldesign of targeted antimicrobial purine-related drugs. To date, very fewhomologs have been characterized experimentally in detail and only two, thexanthine permease XanQ and the uric acid/xanthine permease UapA, have beenstudied extensively with site-directed mutagenesis. Recently, thehigh-resolution structure of a related homolog, the uracil permease UraA, hasbeen solved for the first time with crystallography. In this review, I summarizecurrent knowledge and emphasize how the systematic Cys-scanning mutagenesis ofXanQ, in conjunction with existing biochemical and genetic evidence for UapA andthe x-ray structure of UraA, allow insight on the structure-function andevolutionary relationships of this important group of transporters. The reviewis organized in three parts referring to (I) the theory of use of Cys-scanningapproaches in the study of membrane transporter families, (II) the state of theart with experimental knowledge and current research on the NAT/NCS2 family,(III) the perspectives derived from the Cys-scanning analysis of XanQ.     

Store-Dependent Entry of Ca<Superscript>2+</Superscript> into Sensory Neurons of the Rat

We studied store-dependent (activated by depletion of the endoplasmic reticulum, ER, store) entry of Ca²⁺ from the extracellular medium into neurons of the rat spinal ganglia (small- and medium-sized cells; diameter, 18 to 36 μm). Activation of ryanodine-sensitive receptors of the ER in the studied neurons superfused by Tyrode solutions containing Ca²⁺ or with no Ca²⁺ was provided by application of 10 mM caffeine. The decay phase of caffeine-induced calcium transients in a Ca²⁺-containing solution was significantly longer than that in a Ca²⁺-free solution. This fact allows us to suppose that such a phenomenon is determined by Ca²⁺ entry into the neuron from the extracellular medium activated by caffeine-induced depletion of the ER store. Substitution of Ca²⁺-free extracellular solution by Ca²⁺-containing Tyrode solution, after depletion of the ER stores induced by applications of 100 nM ryanodine, 200 μM ATP, or 1 μM thapsigargin, resulted in increases in the concentration of intracellular Ca²⁺. These observations allow us to postulate that store-dependent Ca²⁺ entry into the studied neurons is activated after depletion not only of the inositol trisphosphate-sensitive ER store but also of the ryanodine-sensitive store. This entry also occurs after blocking of ATPases of the ER by thapsigargin. The kinetic characteristics of the rising phase of store-dependent Ca²⁺ entry induced by depletion of the ER stores under the influence of various agents are dissimilar; this can be related to different mechanisms of activation of such signals and/or to a compartmental organization of the ER. Neirofiziologiya/Neurophysiology, Vol. 37, No. 3, pp. 277–283, May–June, 2005.     

Sensory receptors of the ovipositor ofTrichogramma maidis [Hym.:Trichogrammatidae]

Sensory receptors of the ovipositor ofTrichogramma maidis are described. Sense organs are found on the 2^nd valvifers (1 type), on the tip of the 3^rd valvulae (2 types) and on the 1^st valvulae (4 types). The nature and possible functions of these sensilla are discussed.      

Research Needs for Understanding and Predicting the Behavior of Managed Ecosystems: Lessons from the Study of Agroecosystems

Managed ecosystems are complex, dynamic systems with spatially varying inputs and outputs that are the result of interrelated physical, biological, and human decision-making processes. To gain an adequate understanding of these systems and predict their behavior, we believe that it is necessary to move beyond stylized theoretical models and loosely coupled disciplinary simulation models to what we describe as “fully integrated models.” Herein we present a conceptual framework for a more integrated approach to the study of managed ecosystems using the example of agricultural ecosystems. We then propose the implementation of a research agenda that fosters coordinated disciplinary research aimed at a better understanding and quantification of linkages across disciplinary models. Key research issues include the effects of spatial scale, the assessment of uncertainty in coupled models, and methods for collecting and analyzing spatially referenced data. Received 6 October 2000; accepted 10 April 2001.     

The Duffy binding protein as a key target for a Plasmodium vivax vaccine: lessons from the Brazilian Amazon

Plasmodium vivax infects human erythrocytes through a major pathwaythat requires interaction between an apical parasite protein, the Duffy bindingprotein (PvDBP) and its receptor on reticulocytes, the Duffy antigen/receptor forchemokines (DARC). The importance of the interaction between PvDBP (region II, DBPII)and DARC to P. vivax infection has motivated our malaria researchgroup at Oswaldo Cruz Foundation (state of Minas Gerais, Brazil) to conduct a numberof immunoepidemiological studies to characterise the naturally acquired immunity toPvDBP in populations living in the Amazon rainforest. In this review, we provide anupdate on the immunology and molecular epidemiology of PvDBP in the BrazilianAmazon - an area of markedly unstable malaria transmission - andcompare it with data from other parts of Latin America, as well as Asia andOceania.     

Sensory structures involved in prey detection on the labial palp of the ant‐hunting beetle Siagona europaea Dejean 1826 (Coleoptera,Carabidae)

Giglio, A., Ferrero E.A., Perrotta, E., Talarico, F.F. and Zetto Brandmayr, T. 2010. Sensory structures involved in prey detection on the labial palp of the ant‐hunting beetle Siagona europaea Dejean 1826 (Coleoptera, Carabidae). —Acta Zoologica (Stockholm) 91 : 328–334 The ultrastructure and distribution of sensilla on the labial palps of a myrmecophagous carabid beetle, Siagona europaea, were investigated using scanning and transmission electron microscopy techniques. Five types of sensilla were identified: three types of sensilla basiconica on the apical sensory area and two types, one sensillum trichodeum and one coeloconicum, on the external palp surface. On morphological grounds, the s. basiconica type 1 were considered as olfactory, the type 2 as gustatory, the type 3 and the s. trichodeum as mechanoreceptive, and the s. coeloconicum as a thermo/hygroreceptor. Their function is discussed in relation to prey detection and habitat adaptations.     

Time Course and Characteristics of the Capacity of Sensory Nerves to Reinnervate Skin Territories outside Their Normal Innervation Zones

Factors involved in the outcome of regeneration of the saphenous nerve after a cut or crush lesion were studied in adult rats with electrophysiological recordings of low-threshold mechanoreceptor activity and plasma extravasation of Evans blue after electrical nerve stimulation that activated C fibers.

In the first series of experiments, saphenous and sciatic nerve section was combined with anastomosis of the transected proximal end of the saphenous nerve to the distal end of the cut tibial nerve. Regeneration of saphenous nerve fibers involved in plasma extravasation and low-threshold mechanoreceptor activity in the glabrous skin was observed 13 weeks after nerve anastomosis. Substance P-, calcitonin gene-related peptide-, and protein gene product 9.5 (PGP-9.5)-immunoreactive (IR) thin epidermal and dermal nerve endings, as well as coarse dermal PGP-9.5-IR nerve fibers and Meissner corpuscles and Merkel cell-neurite-like complexes, were observed in the reinnervated glabrous skin at this time.

In a second series of experiments, the time course of the regeneration of saphenous nerve axons to the permanently sciatic-nerve-denervated foot sole was examined. Saphenous-nerve-induced plasma extravasation and low-threshold mechanoreceptor activity in the saphenous nerve were found in the normal saphenous nerve territory 2, 3, 4, and 6 weeks after sciatic nerve cut combined with saphenous nerve crush in the left hindlimb. Saphenous-nerve-induced plasma extravasation was also present in the glabrous skin normally innervated by the sciatic nerve 3, 4, and 6 weeks after the sciatic cut/saphenous crush lesion. However, no low-threshold mechanoreceptor activity was detected in the saphenous nerve when the glabrous skin area was stimulated.

In a third series of experiments, the fate of the expansion of the saphenous nerve territory after saphenous nerve crush was examined when the crushed sciatic nerve had been allowed to regenerate. Nerve fibers involved in plasma extravasation were observed in the glabrous skin of the hindpaw after saphenous nerve, as well as after tibial nerve, C-fiber stimulation 3, 12, and 43 weeks after the saphenous crush/sciatic crush lesion.

Low-threshold mechanoreceptors from the regenerated saphenous nerve, which primarily innervates hairy skin, seem to be functional in the glabrous skin if the axons are guided by the transected tibial nerve by anastomosis. Furthermore, the results indicate that fibers from the regenerating saphenous nerve that have extended into denervated glabrous skin areas can exist even if sciatic nerve axons are allowed to grow back to their original territory.     

Probing the stability of the modular family 10 xylanase from<Emphasis Type="Italic"> Rhodothermus marinus</Emphasis>

The thermophilic bacterium Rhodothermus marinus produces a modular xylanase (Xyn10A) consisting of two N-terminal carbohydrate-binding modules (CBMs), followed by a domain of unknown function, and a catalytic module flanked by a fifth domain. Both Xyn10A CBMs bind calcium ions, and this study explores the effect of these ions on the stability of the full-length enzyme. Xyn10A and truncated forms thereof were produced and their thermostabilities were evaluated under different calcium loads. Studies performed using differential scanning calorimetry showed that the unfolding temperature of the Xyn10A was significantly dependent on the presence of Ca²⁺, and that the third domain of the enzyme binds at least one Ca²⁺. Thermal inactivation studies confirmed the role of tightly bound Ca²⁺ in stabilizing the enzyme, but showed that the presence of a large excess of this ion results in reduced kinetic stability. The truncated forms of Xyn10A were less stable than the full-length enzyme, indicative of module/domain thermostabilizing interactions. Finally, possible roles of the two domains of unknown function are discussed in the light of this study. This is the first report on the thermostabilizing role of calcium on a modular family 10 xylanase that displays multiple calcium binding in three of its five domains/modules.Communicated by G. Antranikian     

How to resolve the SLOSS debate: Lessons from species-diversity models

The SLOSS debate - whether a single large reserve will conserve more species than several small - of the 1970s and 1980s never came to a resolution. The first rule of reserve design states that one large reserve will conserve the most species, a rule which has been heavily contested. Empirical data seem to undermine the reliance on general rules, indicating that the best strategy varies from case to case. Modeling has also been deployed in this debate. We may divide the modeling approaches to the SLOSS enigma into dynamic and static approaches. Dynamic approaches, covered by the fields of island equilibrium theory of island biogeography and metapopulation theory, look at immigration, emigration, and extinction. Static approaches, such as the one in this paper, illustrate how several factors affect the number of reserves that will save the most species.This article approaches the effect of different factors by the application of species-diversity models. These models combine species-area curves for two or more reserves, correcting for the species overlap between them. Such models generate several predictions on how different factors affect the optimal number of reserves. The main predictions are: Fewer and larger reserves are favored by increased species overlap between reserves, by faster growth in number of species with reserve area increase, by higher minimum-area requirements, by spatial aggregation and by uneven species abundances. The effect of increased distance between smaller reserves depends on the two counteracting factors: decreased species density caused by isolation (which enhances minimum-area effect) and decreased overlap between isolates. The first decreases the optimal number of reserves; the second increases the optimal number. The effect of total reserve-system area depends both on the shape of the species-area curve and on whether overlap between reserves changes with scale.The approach to modeling presented here has several implications for conservational strategies. It illustrates well how the SLOSS enigma can be reduced to a question of the shape of the species-area curve that is expected or generated from reserves of different sizes and a question of overlap between isolates (or reserves).     

Perception of Environmental Threat in the Shadow of War: The Effect of Future Orientation

People may express high concern for global warming or environmental degradation, but when forced to evaluate the severity of environmental threats in relation to other threats, environmental threats are pushed to the bottom of the list. The present study was based on the premise that prioritizing threats involves, inter alia, hierarchizing the threats according to their perceived temporal proximity and since environmental threats are perceived, relative to other threats, as more temporally distant, they rank low. Future orientation (FO) is an individual-difference variable that describes the tendency to take into account temporally distant considerations. We predicted that environmental threats would be evaluated as more severe by individuals who were more future-oriented. The strongest effect of FO was found to be on concern about global warming and environmental degradation. This indicated that environmental threats were perceived as temporally farthest and, not surprisingly, received the lowest priority. External security threat was a top-priority; its severity evaluation was uncorrelated to FO, indicating that it was perceived as temporally closest. These evaluations significantly affected environmental attitudes and behavior. The implications on promoting environmental behavior in the presence of ever-existing shorter-term existential threats are discussed.     

Using reflexive behaviors of the medicinal leech to study information processing

The interneuronal network that produces local bending in the leech is distributed, in the sense that most of the interneurons involved are activated in all forms of local bending, even those in which their outputs would produce inappropriate movements. Such networks have been found to control a number of different behaviors in a variety of animals. This article reviews three issues: the physiological and modeling observations that led to the conclusion that local bending in leeches is controlled by a distributed system; what distributed processing means for this and other behaviors; and why the leech interneuronal network may have evolved to be distributed in the first place. © 1995 John Wiley & Sons, Inc.