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PubMed1987

The impact of acidification on macroinvertebrate assemblages in welsh streams: towards an empirical model.

The acidification of surface waters has profound ecological consequences. There is a need to predict the effects of possible future patterns of acid deposition on the biological components of fresh waters. This paper describes a model of the relationships between water chemistry and macroinvertebrate assemblages in eighteen streams in the upper Tywi whose catchments are subject to different land uses. Using established statistical techniques on data sets derived from riffle and margin samples taken in spring and summer, the macroinvertebrate assemblages were classified into three groups, which corresponded with streams draining conifer afforested catchments, acidic moorland streams and circumneutral moorland streams. Following principal components analysis to select key environmental variables, the application of multiple discriminant analysis generated two discriminant functions which were related most strongly to mean filterable aluminium concentration and mean total hardness, respectively. The discriminant functions were used to assign site-group membership with 100% success in the case of the spring data set with combined habitats. In addition, multiple regression of the primary ordination axis of each data set on mean aluminium concentration and mean hardness or pH, produced equations which explained 62.0%-87.2% of the variance. We conclude that the methods used here provide an effective analytical and potentially predictive tool for use in the understanding and management of the impact of acidification on freshwater ecosystems.

Journal Article↗
PubMed2004

Evolution of social learning: a mathematical analysis.

Social learning is an important ability seen in a wide range of animals including humans. It has been argued that individual learning, social learning, and innate determination of behavior are favored by natural selection when environmental changes occur at short, intermediate, and long intervals, respectively. Only recently, however, has the hypothesis been examined by means of mathematical models. In this paper, we construct a simple model in which each organism uses one of three genetically determined strategies--it is an individual learner, a social learner or an "innate"--and the three types of organisms are in direct competition with each other. A reduced model, involving only the individual learners and innates, is effectively linear, and we show that by solving the eigenvalue problem of this reduced system we arrive at a good approximation to the global dynamics of the full model. We also study the effect of stochastic environmental changes and reversible mutations among the three strategies. Our results are consistent with the predictions of previous studies. In addition, we identify a critical level of environmental constancy below which only individual and social learners are present.

Animals↗
PubMed1982

Clostridia isolated from the feces of infants during the first year of life.

Clostridia isolated from the feces of ten healthy infants during the first year of life were identified. All infants excreted clostridia during the first week of life; the most common species were Clostridium butyricum, C. paraputrificum, and C. difficile. In the formula-fed infants colonization occurred consistently throughout the year, whereas in some breast-fed infants it was inhibited until weaning. The species isolated most frequently throughout the year were C. paraputrificum, C. butyricum, C. ramosum, C. sartagoformum, and C. perfringens. Of the species often found in infants, C. butyricum, C. difficile, and C. sartagoformum occur rarely in adults, reflecting differences in the environmental conditions in the gut of the two age groups. The mechanism by which environmental conditions select species of clostridia is unknown but may be important to our understanding of a variety of clostridial intestinal infections. It was demonstrated that species of clostridia which have been implicated in the etiology of neonatal necrotizing enterocolitis form part of the normal infant gastrointestinal microflora.

Breast Feeding↗
PubMed1998

Intracellular proteinases of invertebrates: calcium-dependent and proteasome/ubiquitin-dependent systems.

Cytosolic proteinases carry out a variety of regulatory functions by controlling protein levels and/or activities within cells. Calcium-dependent and ubiquitin/proteasome-dependent pathways are common to all eukaryotes. The former pathway consists of a diverse group of Ca(2+)-dependent cysteine proteinases (CDPs; calpains in vertebrate tissues). The latter pathway is highly conserved and consists of ubiquitin, ubiquitin-conjugating enzymes, deubiquitinases, and the proteasome. This review summarizes the biochemical properties and genetics of invertebrate CDPs and proteasomes and their roles in programmed cell death, stress responses (heat shock and anoxia), skeletal muscle atrophy, gametogenesis and fertilization, development and pattern formation, cell-cell recognition, signal transduction and learning, and photoreceptor light adaptation. These pathways carry out bulk protein degradation in the programmed death of the intersegmental and flight muscles of insects and of individuals in a colonial ascidian; molt-induced atrophy of crustacean claw muscle; and responses of brine shrimp, mussels, and insects to environmental stress. Selective proteolysis occurs in response to specific signals, such as in modulating protein kinase A activity in sea hare and fruit fly associated with learning; gametogenesis, differentiation, and development in sponge, echinoderms, nematode, ascidian, and insects; and in light adaptation of photoreceptors in the eyes of squid, insects, and crustaceans. Proteolytic activities and specificities are regulated through proteinase gene expression (CDP isozymes and proteasomal subunits), allosteric regulators, and posttranslational modifications, as well as through specific targeting of protein substrates by a diverse assemblage of ubiquitin-conjugases and deubiquitinases. Thus, the regulation of intracellular proteolysis approaches the complexity and versatility of transcriptional and translational mechanisms.

Animals↗
PubMed1992

Diabetic nephropathy in insulin-dependent patients.

Diabetic nephropathy is a serious complication of insulin-dependent diabetes mellitus (IDDM) that affects 30% to 40% of IDDM patients with a predictable time of onset. Epidemiologic data suggest that either a genetic susceptibility, perhaps for hypertension (HTN), or an environmental exposure selects out that subset of IDDM patients and destines them to develop diabetic nephropathy. Hopefully, assessing glomerular hyperfiltration, urinary albumin excretion rate (AER), glycemic control, mean arterial pressure (MAP), and perhaps early morphologic changes will allow early identification of this high-risk group of IDDM patients before overt nephropathy is present. Once nephropathy appears, renal function inexorably declines, although the natural history of this progression may be changing with earlier therapeutic intervention. IDDM patients with nephropathy suffer a high mortality rate compared with IDDM patients without nephropathy or with nondiabetic end-stage renal disease patients. This is primarily due to malignant atherosclerotic disease manifested as coronary, peripheral, and cerebral arterial disease. Therapeutic interventions of demonstrated benefit in slowing the rate of decline of glomerular filtration rate (GFR) include blood pressure control and low-protein diets. Strict blood sugar control or treatment with aldose reductase inhibitors, converting enzyme inhibitors (CEIs), or inhibitors of advanced glycosylation end-product formation are of possible benefit, but are awaiting clinical trial results.

Diabetes Mellitus, Type 1↗
PubMed2004

Chemoselective hydrogenation of substituted nitroaromatics using novel water-soluble iron complex catalysts.

Chemoselective hydrogenation of substituted nitroaromatic compounds by water-soluble iron complex catalysts with molecular hydrogen has been reported for the first time. This biphasic catalyst presents an opportunity for a solvent-free hydrogenation. This catalyst system provides a low-cost, efficient alternative to the selective but environmentally unacceptable stoichiometric reductions as well as the supported noble metal catalysts used for hydrogenation. An efficient recycling strategy has resulted in a cumulative turnover number above 6000.

Journal Article↗
PubMed1998

Prediction of aryl hydrocarbon receptor-mediated enzyme induction of drugs and chemicals by mRNA quantification.

Enzyme-specific testing for drug interactions by in vitro techniques has become a routine practice in drug development. With many drugs, enzyme induction has similar importance for the prediction of drug-drug interactions. We developed a method for recognizing enzyme induction mediated via the aryl hydrocarbon receptor. This type of induction may be clinically important since experimental data suggest a higher rate of toxification in induced subjects. Twenty-four drugs and environmental chemicals, selected as prototype inducers or being chemically related to known inducers, including HIV protease inhibitors nelfinavir, saquinavir, ritonavir, and indinavir, were tested for their potency to induce cytochrome P450 1A1 mRNA in human Hela cell cultures by a quantitative reverse transcriptase polymerase chain reaction. Known prototype inducers such as beta-naphthoflavone and 3-methylcholanthrene exhibited the highest inducing potency quantified with an Imax value (maximal induction of cytochrome P450 1A1 mRNA synthesis) of 5.48 and 10.7 x 10(6) mRNA molecules per 150 ng of total RNA, respectively. The enzyme-inducing efficacy of some compounds such as resveratrol (2.92 x 10(6)) and the protease inhibitors was not much lower (2.23-3.08 x 10(6)). All compounds that were structurally similar to benzimidazoles exhibited some extent of enzyme induction; e.g., Imax values were 0.86 x 10(6), 0.20 x 10(6), and 0.14 x 10(6) for omeprazole, lansoprazole, and losartan, respectively. To predict the clinical relevance of these inducing effects, the concentration at half-maximal induction IM was estimated; the plasma concentrations of these drug substances were within 1 order of magnitude of the IM values, upon usual dosage. In conclusion, cytochrome P450 1A1 enzyme induction by drugs is a common phenomenon, though there is a great range in the inducing efficacy. In vitro prediction of enzyme induction may be useful for explaining or foreseeing drug interactions, drug side effects, or toxicity by xenobiotics.

Algorithms↗
PubMed2003

Formicitylenchus oregonensis n. g., n. sp. (Allantonematidae: Nematoda), the first tylenchid parasite of ants, with a review of nematodes described from ants.

The first tylenchid parasite of ants, Formicitylenchus oregonensis n. g., n. sp., is described from a queen carpenter ant Camponotus vicinus Mayr in Western Oregon, USA. The new genus is characterised by the excretory pore anterior to the nerve-ring and rounded tails in the free-living adults, a stylet bearing basal thickenings in the free-living female, a smaller stylet lacking basal thickenings in the male and a short, crenulate leptoderan bursa. The mature parasitic female is light yellow and ovoviviparous. F. oregonensis n. sp. is closely related to members of Metaparasitylenchus Wachek, 1955, with species parasitising beetles living under bark or in rotten wood, a habitat similar to that of carpenter ants. However, males of Metaparasitylenchus are characterised by a fairly long tail with a broad peloderan bursa. It is suggested that this case of tylenchid parasitism in ants is an example of environmental host selection. A review of the described nematode parasites of ants is presented.

Abdomen↗
PubMed1999

Emerging fungal pathogens: evolving challenges to immunocompromised patients for the twenty-first century.

Opportunistic fungi have emerged during the past decade as important causes of morbidity and mortality in immunocompromised patients. Candida species constitute the third to fourth most common causes of nosocomial blood stream infections, and Aspergillus species have emerged as the most common infectious cause of pneumonic mortality in bone marrow/stem cell transplant recipients. Among HIV-infected patients, meningoencephalitis due to Cryptococcus neoformans ranks among the most common AIDS-defining infections. Hyaline septated filamentous fungi, such as Fusarium species, Acremonium species, Paecilomyces species, and Trichoderma species, are increasingly reported as causing invasive mycoses refractory to conventional therapy. Dematiaceous septated filamentous fungi, such as Pseudallescheria boydii, Bipolaris species, and Cladophialophora bantiana cause pneumonia, sinusitis, and CNS infection unresponsive to current therapy. An increasing number of different members of the class of Zygomycetes are reported as causing lethal infections, despite aggressive medical and surgical interventions. Yet the treatment for zygomycosis has not changed in approximately 40 years. The prevalence of the endemic mycoses, such as those due to Penicillium marneffei, Coccidioides immitis, and Histoplasma capsulatum, has been reported to expand rapidly in response to environmental exposures and increased numbers of vulnerable hosts in endemic regions of the world. Dermatophytoses are occurring with increasing prevalence and morbidity in elderly and immunocompromised patients. As we enter the next millennium, we may anticipate that emergent fungal infections will continue to develop in the settings of permissive environmental conditions, selective antifungal pressure, and an expanding population of immunocompromised hosts.

AIDS-Related Opportunistic Infections↗
PubMed2005

Effect of MnSO4 on the chromium removal from the leather industry wastewater.

Chromium (VI) is one of the heavy metals in water and wastewater that has the most toxic characteristic. Consequently, it is dangerous for human and environmental health. Various methods are used for removal of the chromium from wastewater, and new methods have been developed in recent years. Recent studies and investigations on the removal of environmental pollution selected methods that were economical, of optimum efficiently and could be carried out easily. In this study, the removal of Cr6+ in the leather industry wastewater is investigated using MnSO4 that was used easily and economically. Experimental studies are performed in two phases. In the first phase, the optimum MnSO4 dose for removal of Cr6+ was determined. In the second phase, the optimum pH was studied. About 96% removal of chromium was launched with 530 mg l(-1) MnSO4 dose at pH value 9 in the wastewater sample.

Animals↗
PubMed1994

Interruption of rotavirus spread through chemical disinfection.

INTRODUCTION: Rotaviruses, which are among the most important infectious causes of acute diarrhea, frequently cause outbreaks in hospitals, daycare centers, schools, and nursing homes. These viruses can remain viable on inanimate surfaces for many days and infectious rotavirus particles have been recovered from hands and a variety of surfaces and objects. Casual contact can lead to the transfer of these viruses from contaminated to clean surfaces. Therefore, animate and inanimate surfaces may play a complementary role in the spread of these viruses. OBJECTIVE: In this study, we compared the capacity of a disinfectant spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm free chlorine), a quarternary ammonium (quat)-based product (7.05% quat diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) to interrupt the transfer of a human rotavirus (DS-1) from stainless steel disks to fingerpads of volunteers with a 10-second contact at a pressure of 1 kg/cm2. DESIGN: Each disk received a 10 microL inoculum containing 1.0 x 10(4) to 7.0 x 10(4) plaque-forming units (PFU) of the virus suspended in 10% feces. The inoculum was dried for 1 hour and overlaid with 20 microL of either tap water or the test product. RESULTS: A 10-minute exposure to tap water reduced the virus titer by 52.3% +/- 11.7%. The disinfectant spray was able to reduce virus infectivity by > 99.99% after a contact of 3 to 10 minutes. The loss in virus infectivity after a 10-minute treatment with the quat was almost the same (54.7% +/- 17.8%) as seen with tap water. The activities of the bleach and the phenolic were very similar with losses in PFU of 97.9% +/- 0.4% and 95% +/- 5.36%, respectively. No detectable virus was transferred to fingerpads from disks treated with disinfectant spray, the bleach, and the phenolic. Contact of the fingerpads with tap water- or quat-treated disks resulted in the transfer of 5.6% +/- 1.1% and 7.6% +/- 2.5% of the remaining infectious virus, respectively. CONCLUSION: These findings emphasize the care needed in the selection of environmental surface disinfectants in preventing the spread of rotaviral infections.

Adult↗
PubMed2025

Annotated genome of the Atlantic dog whelk, Nucella lapillus.

Nucella lapillus is an important player in rocky shore food chains and has been a focal organism of ecological and evolutionary studies for decades. Despite poor dispersal, they have a broad geographic range, which makes them an ideal species to examine isolation by distance and selection across environmental gradients. Here we present the fully annotated genome of N. lapillus generated with Oxford Nanopore Techonology sequencing at ∼37× coverage. The genome assembly is 2.32 Gbp and consists of 2,525 contigs, with an N50 length of 2 Mbp. Repeat annotation identified 2,491 families that cover 67.56% of the genome, which is similar to other gastropods. Despite its large size and high proportion of repeats, the genome is of high quality. Benchmarking Universal Single-Copy Ortholog (BUSCO) analysis revealed a score of 96.8%. Functional annotation of the genome produced 45,848 protein-coding genes with a 96.6% BUSCO score. Genomic resources for mollusks lag behind that of other phyla, perhaps because many of their innate characteristics complicate DNA extraction, sequencing, and assembly. This new N. lapillus genome will increase our genomic understanding of the second largest phylum (and the most diverse class within said phylum) and serve as a key resource to advance studies on the organismal biology and population genetics of this iconic species as well as the connection between genomic variation and community-level processes.

Animals↗
PubMed2006

The historical perspective of dryland agriculture: lessons learned from 10,000 years of wheat cultivation.

Wheat is one of the founder crops of Western agriculture. This study reconstructs agronomic conditions, potential yields, and kernel weight in the beginnings of cultivation of domesticated free-threshing wheat, c. 8000 BC. The carbon and nitrogen stable isotope compositions and the dimensions of fossil grains of naked wheat (Triticum aestivum/durum) were analysed. Samples were collected in Tell Halula and Akarçay Tepe, two Neolithic archaeological sites from the Middle Euphrates (the claimed core area for wheat domestication). The samples analysed include the oldest reported remains of naked wheat. Consistently wetter conditions but lower kernel weights were found in the Neolithic compared with the present day. Besides, the estimated yields were clearly beyond what is expected from the gathering of wild stands of cereals. Patterns of phenotypic adaptation achieved by wheat after its diffusion through the Mediterranean were also assessed. On the one hand, the study looked at variation in morphophysiological traits as related to local climate in a set of 68 durum wheat landraces from the Middle Euphrates. On the other hand, an assessment was made of regional adaptation around the Mediterranean Basin in a set of 90 landraces, traditional varieties, and modern cultivars from different origins by characterizing agronomic and morphophysiological variability. Significant relationships were observed between phenotypic variation among landraces from the Middle Euphrates and both minimum temperatures and the ratio of precipitation to potential evapotranspiration of the sites of origin. In addition, consistent differences in grain yield, plant structure, and water status were found among genotypes following both north-south and east-west gradients across the Mediterranean. These differences are associated with contrasting environmental and selection pressures.

Adaptation, Physiological↗
PubMed1988

A positive approach to the treatment of aggressive brain injured clients.

A broad spectrum behavior therapy approach was used to treat physical aggression in five brain injured clients. The approach employed high density reinforcement, reinforcer sampling, environmental control, selection of appropriate responses, inconvenience review, self-control training and self-monitoring. All five clients showed significant decreases in aggression immediately after the implementation of the program.

Adolescent↗
PubMed1975

Alterations in hypothalamic function following thermal injury.

Nine burn patients with a mean burn size of 39% (range, 23-65%) and five normal individuals studied in an environmental chamber selected optimal comfort temperature by regulating a bedside temperature control unit. The normal individuals selected 27.8 degrees C plus or minus 0.6 (SE) as the comfort temperature and their mean skin temperature was 33.4 plus or minus 0.6 and core temperature 36.9 plus or minus 0.1 while in this environment. In contrast, the burn patients maintained a higher ambient comfort temperature (mean 30.4 plus or minus 0.7, p less than 0.05 when compared to controls) associated with an elevated core (38.4 plus or minus 0.3, p less than 0.01) and surface temperature (35.2 plus or minus 0.4, p less than 0.05). Human growth hormone response to insulin hypoglycemia and arginine infusion was measured in nine additional burn patients (mean burn size, 52%; range, 23-90%) and five normals. Fasting HGH was significantly elevated (1.7 plus or minus 0.2 ng/ml, n = 18, versus control of 0.9 plus or minus 0.1, n = 10, p less than 0.001), despite fasting hyperglycemia in the burn patients (123 plus or minus 5 mg/100 glycemia in the burn patients (123 plus or minus 5 mg/100 ml versus 91 plus or minus 2, p less than 0.001). HGH response to insulin hypoglycemia was diminished in the burn patients with peak HGH value in patients averaging 12.6 ng/ml compared to 27.8 in the recovered patients and 32.6 in the controls (p less than 0.01). Patients receiving an arginine infusion also demonstrated diminished HGH response following injury. The HGH response to known stimuli returned toward normal with time and recovery in the surviving patients. Alterations in comfort temperature, fasting blood glucose, and glucose-HGH interaction occur following thermal trauma. These changes taken together suggest that metabolic responses to injury may be the consequence of homeostatic readjustment within the hypothalamus.

Adolescent↗
PubMed1990

A polygenic model for the evolution and maintenance of conditional strategies.

We develop a genetic model for conditional strategies which places such strategies in the context of phenotypic plasticity. The model, which treats conditional strategies as polygenic threshold traits, indicates that, given requisite genetic variation in reaction norms, conditional strategies will evolve to their optimum level and be maintained by stabilizing selection, provided environmental variation results in a fitness trade-off for the alternative conditional phenotypes. The precise value for the evolutionary optimum is found to depend primarily on the probability density function of the environmental variation that influences the production of the conditional phenotypes and the magnitude of the fitness trade-offs of the conditional phenotypes across such environmental variation. The model is tested by application to three well-studied conditional strategies. In each case the predictions of the model are in good agreement with the results of these studies.

Animals↗
PubMed2004

Measurement of the setting expansion of phosphate-bonded investment materials: Part I - Development of the Casting-Ring Test.

The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the 'Casting-Ring Test', the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14%, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation.

Chemical Phenomena↗