Biosurfactant-induced remediation of contaminated marine sediments: Current knowledge and future perspectives.

The contamination of marine sediments is widespread in coastal regions of the world and represents a major concern for the potential detrimental consequences on ecosystems' health and provision of goods and services for human wellbeing. Thus, there is an urgent need to find sustainable and eco-compatible solutions for the remediation of contaminated sediments. Bioremediation is a low cost and environmental-friendly strategy with a high potential for the remediation of contaminated marine sediments. Here we review the potential application of biosurfactants produced by microbial taxa for the remediation of contaminated marine sediments and we discuss future research needs to develop efficient and eco-sustainable biosurfactant-based strategies for the recovery of contaminated marine sediments, in view of large-scale applications.

Marine microorganisms as a promising and sustainable source of bioactive molecules.

There is an urgent need to discover new drug entities due to the increased incidence of severe diseases as cancer and neurodegenerative pathologies, and reducing efficacy of existing antibiotics. Recently, there is a renewed interest in exploring the marine habitat for new pharmaceuticals also thanks to the advancement in cultivation technologies and in molecular biology techniques. Microorganisms represent a still poorly explored resource for drug discovery. The possibility of obtaining a continuous source of bioactives from marine microorganisms, more amenable to culturing compared to macro-organisms, may be able to meet the challenging demands of pharmaceutical industries. This would enable a more environmentally-friendly approach to drug discovery and overcome the over-utilization of marine resources and the use of destructive collection practices. The importance of the topic is underlined by the number of EU projects funded aimed at improving the exploitation of marine organisms for drug discovery.

Population genetic structure of Pseudatomoscelis seriatus (Hemiptera: Miridae) in the cotton-growing regions of the United States.

The cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae) is an economically important insect pest of cotton in the United States. However, reports of cotton fleahopper infestation and its management in cotton fields are restricted primarily to Texas, Oklahoma, and Arkansas. The objective of this study was to understand the genetic diversity of cotton fleahopper populations infesting cotton in the cotton-growing areas of the United States. Amplified fragment length polymorphism markers were used to detect genetic diversity and to characterize geographic genotypes across the distribution of the cotton fleahopper in the United States. We used 172 individuals and 559 amplified fragment length polymorphism loci in this study and found significant, but low, level of genetic differentiation among geographic populations (F(ST) = 0.02; P < 0.0001). Molecular fingerprints of cotton fleahopper populations were partitioned into three broad regional genetic populations with a western, central, and eastern distribution. The western (Arizona) and eastern (Florida, Georgia, South Carolina, and North Carolina) populations are genetically distinct, whereas the central (Texas, Oklahoma, Arkansas, Mississippi, Louisiana, and Alabama) population represents an admixed population, which include both western and eastern populations. These results suggest considerable gene flow among the populations within regions but restricted gene flow among populations from eastern and western region.

Host preference of cotton fleahopper, Pseudatomoscelis seriatus (Reuter) is not labile to geographic origin and prior experience.

Several phytophagous insects exhibit distinct preference for their host plants. In widely distributed generalist insects, host preference can be influenced by geographic variation in host plant distribution and abundance as well as by prior experience. We have studied host preference of the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), a pest of cotton in Texas and other neighboring states, by measuring olfactory orientation to horsemint (Monarda punctata L.) and cotton (Gossypium hirsutum L.). Horsemint is one of the primary, native, wild hosts of cotton fleahopper during late-spring and early summer in Texas, and it is commonly believed to be the main source of this pest in cotton. Although the abundance of horsemint, and therefore the fleahopper exposure to it, varies geographically, cotton fleahopper's preference for this native host-plant is maintained across two ecoregions in Texas, TX High Plains (Lubbock area) and Brazos Valley (College Station area). Similarly, preference for horsemint was retained regardless of prior experience with cotton throughout all the life stages of the insect. This fixed preference of cotton fleahopper to horsemint could be because of their ancestral insect-plant interaction, better fitness of cotton fleahopper on horsemint, and relatively low abundance of horsemint compared with cotton. Information gained from this study could be used to implement cultural control practices such as trap cropping, to develop attractants to monitor this pest, or both.

Características de actividad, iniciativa personal y pasividad en la construcción de proyectos laborales: un estudio en jóvenes escolarizados de la Ciudad Autónoma de Buenos Aires / Activity, personal initiative and passivity characteristics en work projects construction: a study in school attending young people in Ciudad Autónoma de Buenos Aires

La inserción laboral de los jóvenes escolarizados se ha modificado sustancialmente en los últimos años. Uno de los requerimientos que se les exige para ingresar y mantenerse en el trabajo es que tengan características personales de actividad. Se trata de un estudio cuantitativo en el que se trabajó con una muestra de quinto y sexto (n=399) de jóvenes de seis escuelas medias públicas de la Ciudad Autónoma de Buenos Aires. Se evaluaron las características de actividad e iniciativa con la escala Self-reported initiative y la característica de pasividad con la escala Passivity (Frese et al., 1997). Se han realizado análisis descriptivos y análisis de varianzas (ANOVA). Asimismo se ha estudiado mediante una regresión lineal múltiple qué variables explican mejor la iniciativa personal.Se han encontrado diferencias significativas en las características personales de iniciativa en la variable sexo a favor de las mujeres. Además, los alumnos de la especialidad técnica son más activos en relación a los alumnos de la comercial y los que tienen experiencia laboral respecto de los que no la poseen.

Características de actividad, iniciativa personal y pasividad en la construcción de proyectos laborales: un estudio en jóvenes escolarizados de la Ciudad Autónoma de Buenos Aires / Activity, personal initiative and passivity characteristics en work projects construction: a study in school attending young people in Ciudad Autónoma de Buenos Aires

La inserción laboral de los jóvenes escolarizados se ha modificado sustancialmente en los últimos años. Uno de los requerimientos que se les exige para ingresar y mantenerse en el trabajo es que tengan características personales de actividad. Se trata de un estudio cuantitativo en el que se trabajó con una muestra de quinto y sexto (n=399) de jóvenes de seis escuelas medias públicas de la Ciudad Autónoma de Buenos Aires. Se evaluaron las características de actividad e iniciativa con la escala Self-reported initiative y la característica de pasividad con la escala Passivity (Frese et al., 1997). Se han realizado análisis descriptivos y análisis de varianzas (ANOVA). Asimismo se ha estudiado mediante una regresión lineal múltiple qué variables explican mejor la iniciativa personal.Se han encontrado diferencias significativas en las características personales de iniciativa en la variable sexo a favor de las mujeres. Además, los alumnos de la especialidad técnica son más activos en relación a los alumnos de la comercial y los que tienen experiencia laboral respecto de los que no la poseen.(AU)

Oral mucosa alterations induced by cyclosporin in mice: morphological features.

BACKGROUND AND OBJECTIVE: The mechanisms involved in the pathogenesis of cyclosporin A-induced gingival hyperplasia are not well understood. The present work aimed at developing a mouse model with the characteristics of the human process, i.e. time of appearance, dose dependency and the capacity of developing in a variety of genetic backgrounds. This model would present the advantages of using a very well known animal species, small and easy to handle, with a number of experimental reagents (antibodies, etc.) already available against its products. METHODS: Three different strains of mice were used: CBA, F1(C57Bl x DBA), Balb/c. Groups of mice received different concentrations of cyclosporin A (CSA) (10 mg/kg, 25 mg/kg and 40 mg/kg body weight) intraperitoneally five times a week. Anatomical and histological alterations were recorded at various time intervals. RESULTS: All strains of mice presented gingival hyperplasia after 8 weeks of CSA treatment. A dose-dependency was observed with regard to the time of first appearance of alterations. Increased redness was seen in all animals at the sixth week, independent of the dosage used. Histologic examination exhibited increased vascularization, epithelial and connective tissue thickening, edema and a mononuclear infiltrate. CONCLUSIONS: It was possible to develop CSA-induced gingival hyperplasia in mice with the characteristics described in humans and other species. The use of this animal model may help in the elucidation of the process involved in CSA-induced gingival overgrowth.

Impact of recombinant baculovirus field applications on a nontarget heliothine parasitoid, Microplitis croceipes (Hymenoptera: Braconidae).

The kill times of two viruses infectious to the heliothine pest complex indigenous to Texas cotton have been significantly reduced by expressing a scorpion toxin gene. Autographa californica nucleopolyhedrovirus (NPV) and Helicoverpa zea NPV express the toxin only in permissive lepidopteran hosts. The toxin, however, could indirectly harm members of upper trophic levels that feed upon and parasitize infected larvae producing the toxin. In this study, the effects of recombinant and wild-type viruses on Microplitis croceipes (Cresson) were studied in cotton using Heliothis virescens (F.) (Lepidoptera: Noctuidae) as hosts. Two recombinant viruses, their two wild-type progenitor viruses, and untreated cotton served as the five treatments of study. Larvae were previously parasitized 2 and 4 d before being confined for 72 h to cotton terminals treated with field rates of virus or left untreated. The sexes of adult M. croceipes that emerged from the recovered H. virescens larvae were determined and their head capsule widths were measured. Polymerase chain reaction (PCR) searched their extracts for virus DNA. There were no differences in percentage emergence and sex ratios of parasitoids among recombinant, wild-type, and control treatments. Significantly more wasps emerged from the 4-d cohort, but these wasps were significantly smaller than wasps from the 2-d cohort regardless of treatment. Finally, PCR found only 15-25% of the recovered H. virescens larvae and none of the emergent M. croceipes had detectable levels of viral DNA. Recombinant and wild-type viruses had a similar, minimal impact on emergent wasps, and the probability of virus dispersal via parasitoids is low in the system tested.

Self-regulating interest: the moderating role of hardiness and conscientiousness.

Sansone, Weir, Harpster, and Morgan (1992) found that individuals intentionally regulated their interest in an activity when they had both the need (the task was boring) and a reason to exert the effort (an ostensible health benefit). The present study examined Hardiness and Conscientiousness as moderators of this self-regulatory process when individuals had the option of quitting in addition to the options of persisting and of engaging in interest-enhancing strategies. Undergraduates performed a boring copying activity under instructions to stop when they felt they could evaluate the task. Half were told that their evaluations would help researchers develop good jobs for others (Benefit). Results indicated high hardy individuals copied more letters when they were provided the additional Benefit information, and this effect was mediated through their attempt to make the task more interesting. High conscientious individuals persisted longer than individuals lower in conscientiousness independently of the benefit manipulation or strategy use. Implications of individual differences in self-regulation of motivation are discussed.

The role of problem definitions in understanding age and context effects on strategies for solving everyday problems.

The participants (107 preadolescents, 124 college students, 118 middle-aged adults, and 131 older adults) described 2 everyday problems (1 unconstrained, the other constrained to 1 of 6 domains) that they experienced and their goals and strategies. Problem definitions reflected interpersonal or competence components or both; strategies reflected altering cognitions, actions, or regulating and including others. Age differences in problem definitions were found. For unconstrained-domain problems, age and problem definition were related to strategies; for unconstrained-domain problems age differences in strategies were not found. For constrained-domain problems, strategies related to problem domain and problem definition, with problem definition the better predictor of strategies. The results illustrate the value of individuals' problem definitions for addressing age and context effects on strategies used.

The association of mutans streptococci and non-mutans streptococci capable of acidogenesis at a low pH with dental caries on enamel and root surfaces.

Coronal dental plaque from each of 12 caries-positive subjects (Group I) was pooled from "white spot" tooth surface areas and, separately, from sound surface areas; sound surface areas in each of 18 caries-free subjects (Group II) were sampled similarly. Two samples, one consisting of material from a root-surface lesion and another of plaque from a sound root-surface area, were obtained from each of another 10 subjects (Group III). The samples from Groups I and II were evaluated for: (1) pH-lowering potential in vitro with dispersed plaque suspensions, excess glucose supply, and a 60-minute test; (2) the levels of mutans streptococci (MS) and lactobacilli; and (3) the distribution of the predominant non-mutans streptococci (non-MS) according to their final pH in glucose broth; only microbial analysis was done for the Group III samples. The levels of the MS were generally positively associated with caries. A weaker positive association was found for the levels of those non-MS capable of acidogenesis at low pH (final pH < 4.4). The latter generally far outnumbered the MS in all types of samples. The levels of lactobacilli were nearly always very low. The pH-lowering potential (final pH and pH drop rate) was higher for plaque from "white spot" areas than for plaque from sound surface areas (Group I). The samples from caries-free subjects (Group II), however, exhibited a pH-lowering potential which was not significantly different from that of both types of samples from the caries-active subjects (Group I).(ABSTRACT TRUNCATED AT 250 WORDS)

Once a boring task always a boring task? Interest as a self-regulatory mechanism.

A process was proposed through which individuals regulate their motivation to perform necessary but uninteresting activities over time. If committed to continuing, individuals may engage in interest-enhancing strategies that can change the activity into something more positive to perform. In Study 1 Ss performed novel tasks and generated strategies to make regular performance interesting. In Study 2 Ss actually used these strategies primarily in conditions indicating a self-regulatory attempt: The task was currently boring, there was a perceived reason to continue (alleged health benefit), and a relevant strategy was available. Strategy use was associated with a change in activity definition and greater likelihood of subsequently performing the activity. In Study 3 Ss beliefs about how to maintain motivation to perform more everyday activities emphasized the importance of regulating interest relative to other self-regulatory strategies.

In vitro acidogenic potential and mutans streptococci of human smooth-surface plaque associated with initial caries lesions and sound enamel.

Samples of human dental plaque were pooled from several "white spot" smooth tooth surface areas as well as from several clinically-sound tooth surface areas in each of 12 caries-positive college students. Each of the two samples from each subject was used for the determination of: (1) pH-lowering potential in vitro involving dispersed plaque suspensions, excess glucose supply, and a 60-minute test, and (2) the proportions of mutans streptococci and lactobacilli. When all subjects were considered, plaques from "white spot" areas, as compared with samples from sound surface areas, were characterized by significantly higher proportions of mutans streptococci, a lower starting ("resting") pH, a faster rate of pH drop between pH 6.0 and 5.0, and a lower minimum pH of the suspension; the lactobacillus proportions were generally very low in both types of plaques. For individual subjects, however, the proportions of mutans streptococci in plaque associated with "white spot" areas showed a wide range (0.001-10.0%), and samples with high as well as low levels of these micro-organisms could exhibit a high rate of pH drop and a low pH minimum. This suggests that, besides mutans streptococci and lactobacilli, other bacteria capable of acidogenesis at a low pH may contribute to the high pH-lowering potential exhibited by many plaques.

Mutans streptococci and non-mutans streptococci acidogenic at low pH, and in vitro acidogenic potential of dental plaque in two different areas of the human dentition.

Samples of human dental plaque were obtained from sound tooth surfaces in the lower anterior and upper posterior areas of each of 11 subjects with various degrees of caries experience. Both types of plaque were compared for: (1) their pH-lowering potential [pH at 10 and 60 min after sugar addition and the pH drop between 0 and 10 min (delta pH)] with an in vitro method involving dispersed plaque suspensions and excess glucose supply; (2) the proportions of mutans streptococci; and (3) the distribution of the predominant non-mutans streptococci according to their final pH in glucose broth. Compared with plaque from the lower anterior area, plaque from the upper posterior area exhibited a significantly higher pH-lowering potential, i.e., a lower pH at 10 and 60 min and a greater delta pH and significantly higher levels of mutans streptococci. The final pH values for the non-mutans streptococci exhibited a wide range from about 4.4 to over 5.0. The proportions of such organisms designated as capable of acidogenesis at low pH (final pH less than 4.6), whether expressed as a percentage of the total non-mutans streptococci or of the total plaque flora, were significantly increased in plaque from the upper posterior area. The proportions of non-mutans streptococci capable of acidogenesis at low pH in plaque from the upper posterior area were also significantly increased, with decreasing pH values at 10 and 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Remembering less and inferring more: effects of time of judgment on inferences about unknown attributes.

Perceivers often infer the values of unknown attributes from evaluative expectancies. In 2 experiments, inferences about unknown attributes of a target made shortly after initial processing tended to be moderate, as perceivers presumably adjusted for the lack of directly relevant evidence. However, stronger inferences were drawn with the passage of time as memory of the absence of information faded. Expertise moderated this effect, as subjects highly knowledgeable of the target domain were much less likely than low or moderate knowledge subjects to draw extreme inferences over time. Memory-based inferences about unknown attributes were also found to be held with greater confidence than inferences made shortly after stimulus presentation.

Effects of instruction on intrinsic interest: the importance of context.

Two studies examined how contextual cues influence the impact of receiving instructions for improving performance on intrinsic motivation. The authors proposed that whether instruction enhances or decreases motivation depends on the salience of performance goals. Goal salience was proposed to be a function of how an individual defines the activity, which, in turn, may be influenced by contextual features. To test this hypothesis, the authors used a computer game that emphasized fantasy in addition to skill, and they varied the presence of contextual cues highlighting performance. In Study 1, the authors varied the presence of prior performance feedback, and found that instruction decreased interest only when no prior performance feedback (positive or negative) was received. In Study 2, the authors explicitly manipulated contextual salience by describing the activity's goals as either skill- or fantasy-related. Instruction decreased interest in the fantasy-emphasis context, but increased interest in the skill-emphasis context. Furthermore, when instruction matched perceived goals Ss experienced greater positive affect while performing the task. The implications for models of intrinsic motivation are discussed.

Comparison of two methods for the small-scale extraction of DNA from subgingival microorganisms.

Two methods were compared for the extraction of DNA from small numbers of bacterial cells. The first method involved lysis of cells with SDS in the presence of proteinase K, treatment with hexadecyltrimethyl ammonium bromide (CTAB) and precipitation of DNA with isopropanol. In the second method, DNA was extracted by treatment of the cells with guanidine hydrochloride (GHCl) and precipitated with ethanol. Thirty strains of representative gram positive and gram negative species were included in the study. Preparations derived from confluent growth on one-quarter of the surface of agar plates and from 10(8) cells were subjected to each extraction procedure and analyzed for their content of DNA, RNA and protein. The suitabilities of the resultant DNA for restriction enzyme digestion and biotin-labelling by a random primer technique were also assessed. In general, the CTAB method yielded greater amounts of DNA than the GHCl procedure. RNA was present in most preparations of both types, but in amounts detectable only by agarose gel electrophoresis. The latter technique also revealed that DNA was not excessively sheared by either procedure. Protein was detected in some CTAB and GHCl preparations, but was not consistently associated with one or the other method. DNA obtained by both methods could be digested by the restriction enzyme EcoR I. In addition, biotin-labelled DNA probes prepared from CTAB and GHCl preparations were capable of hybridizing with homologous target DNA fixed to nitrocellulose. Since the CTAB method was consistently successful in recovering DNA from preparations containing 10(8) cells, it may be more suitable for the direct treatment of single colonies taken from primary isolation plates or plaque samples.

"Reverse" DNA hybridization method for the rapid identification of subgingival microorganisms.

A "reverse" hybridization method is described, in which whole chromosomal DNA was extracted from 10-20 colonies of "unknown" strains in pure culture and labelled with digoxigenin by a random primer technique. DNA probes were prepared from a total of 23 strains and hybridized with targets containing 100 ng purified, denatured DNA from 38 reference strains fixed to nitrocellulose. 21/23 digoxigenin-labelled DNA probes successfully detected all members of the homologous species present on filters. Probes to Fusobacterium nucleatum strains 364 and MG detected 3/4 and 1/4 members of this species, respectively; 13/23 probes were 100% specific, but cross reactions between 10 probes and DNA targets from closely related, heterologous species occurred in 15/834 possible instances. False-positive reactions that occurred between closely related species were, however, easily distinguished and did not prevent the accurate identification of probe strains. Digoxigenin-labelled probes were capable of detecting 100 pg of homologous DNA. The reverse hybridization procedure allows identification or grouping of a large number of isolates within 3 days and provides a more economical means of characterizing subgingival isolates than predominant cultivable techniques and conventional phenotypic testing. This method could be adapted for the direct identification of microorganisms in subgingival plaque samples.

Nicotine gum and self-help manuals in smoking cessation: an evaluation in a medical context.

This study evaluated the effectiveness of nicotine chewing gum in smoking cessation, when incorporated into a behaviorally oriented self-help program. One hundred ninety-seven patients were randomly assigned to nicotine gum with a self-help manual, a self-help manual without gum, or a control condition, but received no further treatment from the prescribing physician. At six weeks, the nicotine gum group was superior to both the self-help and control conditions. By one year, many gum patients had relapsed, and the treatment effect was no longer significant. Patients who were able to quit initially were most likely to remain ex-smokers in the self-help condition. The clinical importance of these findings is discussed.