Concept Of Functional Groups Research Articles

Importance of demography in understanding disease ecology in small mammals

Small rodents are increasingly used as model animals in disease ecological research. However, many students in the field have an inadequate knowledge of the significance of demographic heterogeneity of reservoir rodent populations and how that affects infection parameters. I summarize here some of the common problems and give a solution, the use of the concept of functional groups, to gain more detailed information and avoid common mistakes (e. g., by drawing conclusion from pooled population samples). I emphasize the importance of seasonality and demography (roles of various population functional subgroups) for parasite/pathogen studies and sampling design to cover the essential components of populations.

The Most Common Functional Groups in Bioactive Molecules and How Their Popularity Has Evolved over Time.

The concept of functional groups (FGs), sets of connected atoms that can determine the intrinsic reactivity of the parent molecule and in part are responsible for the overall properties of the molecule, form a foundation within modern medicinal chemistry. In this Article, we analyze the occurrence of various FGs in molecules described in the medicinal chemistry literature over the last 40 years and show how their development and utilization over time has varied. The popularity of various FGs has not evolved randomly, but instead, clear patterns of use are evident. Various factors influencing these patterns, including the introduction of new synthetic methods, novel techniques, and strategies applied in drug discovery and the better knowledge of molecular properties affecting the success of candidate development, are discussed.

STUDENTS’ DIFFICULTIES IN SOLVING SYNTHESIS ORGANIC COMPOUND PROBLEMS

Solving the synthesis problem of organic compounds requires the understanding of certain organic chemical concepts. Students need to integrate organic chemical concepts to analyze the synthesis stage of organic compounds. Therefore, purposed of this research is want to find the difficulties possessed by students in solving organic synthesis problem. The participants of this research are 14 students of chemistry education in one state university in Papua, Indonesia. The type of this research is descriptive research. The research using multiple choices with reasoning test and essay test as the instruments, that consist of 6 items of multiple choices and 3 essay items. The results analyze by percentage and described. In this research, students are given issues concerning to the concepts of organic chemistry and the synthesis of organic compounds. The result shows students' understanding on the concept of functional group of organic compound is 79%, organic compound structure is 57%, organic stability is 22%, electrophile and nucleophile is 36%, while the concept of reagent, required condition and related product stereochemistry of organic compound less than 20%. It shows students having more difficulties in the concepts of reagent, required condition and related product stereochemistry of organic compound.

Functional groups of plant pathogens in agroecosystems: a review

The concept of functional groups (set of species having similar physiological, ecological or life-history traits) has been largely used for plants, microorganisms, nematodes or insects in agroecosystems. However, this concept has been rarely applied to describe assemblages of plant pathogens. Yet, classification systems in plant pathology resemble this functional approach, as they address different disease processes or life history traits. In this review, we discuss advantages and drawbacks of current classification systems in relation to their application to the ecological management of crop diseases. Then, we propose to reorganize one of the classical plant-pathogen systems in a dichotomous key of functional groups obtained by combining two life-history traits: dispersal and survival strategies. The six functional groups proposed here are soil inhabitants; soil survivors; debris-seed-borne; air-borne; seed-borne, and vector-borne pathogens. We applied these groups to characterize pathogens of two major crops, wheat and tomato, grown in temperate climate regions. Our contribution intends to provide a comprehensive conceptual framework for the design of crop disease management strategies based on ecological principles, as well as to facilitate the interpretation of the occurrence of epidemics in response to the agricultural practices applied in real-world agroecosystems.

Functional groups differ in trait means, but not in trait plasticity to species richness in local grassland communities.

Despite growing interest in incorporating intraspecific variation of functional traits in community-level studies, it remains unclear whether species classified into functional groups based on interspecific trait differences are similar regarding their variation in trait expression in response to varying plant diversity and composition in local communities. In a large biodiversity experiment (Jena Experiment) designed on a trait-based a priori definition of functional groups (grasses, legumes, small herbs, tall herbs), we studied means, extent of variation (coefficient of variation across communities) and plasticity to increased plant diversity (slopes over a logarithmic species richness ranging from 1, 2, 4, 8 and 16 to 60 species) for nine functional traits. Species means and extent of variation in traits related to nitrogen (N) acquisition and N use differed among functional groups and were more similar in phylogenetically closely related species than expected by chance. Species in the same functional group showed a weak phylogenetic signal and varied widely in means and extent of variation in traits related to shoot architecture and to a smaller extent in leaf traits related to carbon acquisition. This indicated that functional groups were less distinguishable in light than in nitrogen acquisition strategies. The direction and degree of trait plasticity to increasing species richness did not show a phylogenetic signal and were not different among functional groups, but varied largely among species within functional groups. Correlation structures in trait means, extent of trait variation and trait plasticity revealed functional tradeoffs in the acquisition of nitrogen and light across species. While correlations between trait means and extent of trait variation varied from trait to trait (positive, negative or unrelated), trait means and trait plasticity were mostly unrelated. Our results suggest that the concept of functional groups is viable, but context-specific trait measurements are required to improve our understanding about the functional significance of intraspecific trait variation and interspecific trait differences in local plant communities.

Enhanced ecological indication based on combined planktic and benthic functional approaches in large river phytoplankton ecology

The occurrence of benthic diatoms in large river plankton is considered to be highly stochastic. Accordingly, the widely applied phytoplankton functional group concept sensu Reynolds (FG) classifies all benthic diatom taxa together. Based on data of a high-frequency 1-year long phytoplankton survey of the Pearl River (China), we tested whether the combination of the FG system with various trait-based classifications of benthic diatoms enhances our ability in predicting the community composition from the local environment. Using the Self-Organizing Map approach, we identified characteristic community compositions based on (i) taxonomic data, (ii) the FG approach, and (iii) the FG system combined with trait-based functional approaches of benthic diatoms: size structure, ecological guilds, and eco-morphological groups. All combined functional approaches enabled better predictions for the community composition than the taxonomic data or the FG system alone. The most reliable approach was the combination of the FG system with ecological guilds of benthic diatoms. Therefore, the occurrence of benthic diatoms in large river phytoplankton can be assessed ecologically in a meaningful way based on combined planktic and benthic functional classifications. The application of this approach seems to be highly relevant in large river phytoplankton ecology, ecological modelling, or in ecological status indication.

An algorithm to identify functional groups in organic molecules

BackgroundThe concept of functional groups forms a basis of organic chemistry, medicinal chemistry, toxicity assessment, spectroscopy and also chemical nomenclature. All current software systems to identify functional groups are based on a predefined list of substructures. We are not aware of any program that can identify all functional groups in a molecule automatically. The algorithm presented in this article is an attempt to solve this scientific challenge.ResultsAn algorithm to identify functional groups in a molecule based on iterative marching through its atoms is described. The procedure is illustrated by extracting functional groups from the bioactive portion of the ChEMBL database, resulting in identification of 3080 unique functional groups.ConclusionsA new algorithm to identify all functional groups in organic molecules is presented. The algorithm is relatively simple and full details with examples are provided, therefore implementation in any cheminformatics toolkit should be relatively easy. The new method allows the analysis of functional groups in large chemical databases in a way that was not possible using previous approaches.Graphical abstract.

Nearsightedness of Oxygen-Containing Functional Groups.

Matter is nearsighted, that is, for a fixed chemical potential, the charge density is only sensitive to perturbations within a radius R. While it is known that the resultant change in the density at point r0 from some perturbation at some other point R (Δn(r0,R)) is a monotonically decreasing function, a plausible range of a chemically significant Δn(r0,R) and the value of R needed to cause these perturbations has not been well studied. Using the functional group, which upon satisfying the necessary atoms/bonds specific to that functional group retains a characteristic chemistry, this paper provides an initial study into the magnitude of both Δn and R, the radius beyond which to affect a given property. Values for Δn are shown to be robust across a variety of DFT functionals and provide a framework for the transfer of the functional group concept to other disciplines, such as metallurgy.

Combining taxonomy and function in the study of stream macroinvertebrates

<p>Over the last fifty years, research on freshwater macroinvertebrates has been driven largely by the state of the taxonomy of these animals. In the great majority of studies conducted during the 2000s macroinvertebrates have been operationally defined by investigators as invertebrates retained by a 250 μ mesh in field sampling devices. Significant advances have been and continue to be made in developing ever more refined keys to macroinvertebrate groups. The analysis by function is a viable alternative when advances in macroinvertebrate ecological research is restricted by the level of detail in identifications. Focus on function, namely adaptations of macroinvertebrates to habitats and the utilization of food resources, has facilitated ecological evaluation of freshwater ecosystems (Functional feeding groups; FFG). As the great stream ecologist Noel Hynes observed, aquatic insects around the world exhibit similar morphologies and behaviors, even though they are in very different taxonomic groups. This is the basis for the FFG analysis that was initially developed in the early 1970s. FFG analysis applies taxonomy only to the level of detail that allows assignment to one of six FFG categories: scrapers adapted to feed on periphyton, detrital shredders adapted to feed on coarse (CPOM) riparian-derived plant litter that has been colonized by microbes, herbivore shredders that feed on live, rooted aquatic vascular plants, filtering collectors adapted to remove fine particle detritus (FPOM) from the water column, gathering collectors adapted to feed on FPOM where it is deposited on surfaces or in crevices in the sediments, and predators that capture live prey. The interacting roles of these FFGs in stream ecosystems were originally depicted in a conceptual model. Thus, there are a limited number of adaptations exhibited by stream macroinvertebrates that exploit these habitats and food resources. This accounts for the wide range of macroinvertebrate taxa in freshwater ecosystems found in different geographical settings that are represented by a much smaller number of FFGs. An example of the generality of the functional group concept is the presence of detrital shredders that are dependent upon riparian plant litter inputs being found in essentially all forested streams world-wide (<em>e.g</em>., across the USA and Canada, Chile, Brazil, West Africa, New Zealand, Australia, Japan, Thailand; Cummins, <em>unpublished</em>). Freshwater macroinvertebrate taxonomic determinations, especially at the species level, may be the best basis for developing specific indices of pollution (tolerance values in ecological tables). However, the FFG method appears to provide better indicators of overall freshwater ecosystem condition.</p>

The phytoplankton functional group concept provides a reliable basis forecological status estimation in the Çaygören Reservoir (Turkey)

The phytoplankton functional group (FG) concept has been successfully used to determine water quality states in both lake and river systems, but is not yet stressed in regular studies in reservoir environments. The purpose of our study was to estimate the ecological status of the temperate Caygoren Reservoir (2007-2009) using the Q(r) FG composition metric, and to test whether it is able to follow the main structuring of the physical and chemical parameters studied. The main occurring coda were codon C (Cyclotella meneghiniana Kutzing, Stephanodiscus neoastraea Hakansson and Hickel), codon T (Gloeotila subconstricta (G.S. West) Printz, Mougeotia sp.), codon X2 (Cryptomonas pyrenoidifera Geitler, Plagioselmis nannoplanctica (H.Skuja) G.Novarino, I.A.N.Lucas and S.Morrall), codon K (Aphanocapsa holsatica (Lemmermann) G.Cronberg and J.KomAirek, Aphanothece clathrata West and G.S.West), and codon S1 (Planktothrix sp.). The seasonal succession of phytoplankton displayed the lake-like coda series of Y (winter) → C (spring) → K/S1 (summer) → T (fall) in each year, which demonstrated well the transitional behavior of reservoirs between lake and river ecosystems. The FG compositions showed high relationships with water temperature, ammonia, phosphate, and light availability in this temperate reservoir, where the Q(r) index estimated reliable water quality states between hypertrophic and oligotrophic conditions.

Survey to compare phytoplankton functional approaches: How can these approaches assess River Nile water quality in Egypt?

The phytoplankton functional group concept (Q(r) index) was used to assess ecological status in the River Nile. Phytoplankton Functional Groups (FGs) and Morpho-Based Functional Groups (MBFGs) were described in the whole river including the main pollution sources. A total of 273 species were classified into 25 FGs and seven MBFGs. The most dominant FGs recorded (D, P, B, M, F, P, J and F) preferred nutrient rich conditions, whereas the appearance of lacustrine groups (W1, T, Y, Lo) reflected an increase of water residence time. Between MBFG groups, VI was the most dominant. The Canonical Corresponding Analysis indicated that the variance explained from environmental conditions is highest for MBFG (78.56%) than for FG (65.57%) and individual species (51.36%). Minimum Q(r) index values were synchronized to spring and the southern section of the river. The least Q(r) values were observed at the discharging point of pollutants and increase toward the highly diluted point. The highest Q(r) values were mainly observed at the upstream and main channel sites. The results suggested that the morpho-functional classification of phytoplankton and Q(r) not only reflects successfully River Nile water quality better than the individual species composition, but can also be used as a monitoring tool to assess the ecological status in the River Nile.

An application of the plant functional group concept to restoration practice on coal mine spoil heaps

AbstractThe history of coal mining in South Poland has left a legacy of many spoil heaps across the landscape. These have presented the opportunity to study their colonisation and spontaneous successional sequences over a long time period. We use the plant functional group (PFG) approach to characterize and compare species diversity on spoil heaps of different ages by utilising the ecological characteristics (PFG categories) of the species recorded during the course of spontaneous vegetation development. By changing species frequency into functional group frequency it was possible to find the significant differences in the functional composition of the studied vegetation and to analyze the dataset using non‐parametric statistics. There was a small increase in the number of species over time, while the frequency of geophytes, nanophanerophytes and megaphanerophytes increased significantly. A significant increase was also recorded for the frequency of competitors, stress‐tolerators and stress‐tolerant competitors and for native species. We found that the significant differences in species composition measured as PFG diversity occurred between the youngest and the oldest age classes. The PFG approach provided valuable insights into the nature of the species composition of the developing vegetation on hard‐coal mine spoil heaps. We suggest that it could be usefully applied in restoration practice in the future by facilitating the natural colonization of native species adapted to local conditions and thus retaining the local gene pool in these areas.

Functional-Segment Activity Coefficient Model. 2. Associating Mixtures

In this work, the recently proposed Functional-Segment Activity Coefficient (F-SAC) model (Ind. Eng. Chem. Res., DOI: 10.1021/ie400170a) is extended for mixtures where hydrogen bonds (HB) can form. The F-SAC model is based on the concept of functional groups with the group interaction energies calculated according to the COSMO-RS theory. In the extension proposed here, hydrogen bonds are described by one additional energy parameter for each HB donor–acceptor pair. The F-SAC parameters for substances not participating in hydrogen bonds were kept unchanged. Additional parameters were calibrated for 25 HB donor–acceptor pairs by using infinite dilution activity coefficient (IDAC) data complemented by VLE data for the ethanol/water system. For the considered IDAC data set, the F-SAC fit was superior to the predictions obtained with UNIFAC (Do). Finally, the predictive strength of the model was assessed using vapor–liquid equilibrium as well as water/alkane mutual solubility data not considered in the model fi...

Application of macrobenthos functional groups to estimate the ecosystem health in a semi-enclosed bay

In this study, the functional group concept was first applied to evaluate the ecosystem health of Bohai Bay. Macrobenthos functional groups were defined according to feeding types and divided into five groups: a carnivorous group (CA), omnivorous group (OM), planktivorous group (PL), herbivorous group (HE), and detritivorous group (DE). Groups CA, DE, OM, and PL were identified, but the HE group was absent from Bohai Bay. Group DE was dominant during the study periods. The ecosystem health was assessed using a functional group evenness index. The functional group evenness values of most sampling stations were less than 0.40, indicating that the ecosystem health was deteriorated in Bohai Bay. Such deterioration could be attributed to land reclamation, industrial and sewage effluents, oil pollution, and hypersaline water discharge. This study demonstrates that the functional group concept can be applied to ecosystem health assessment in a semi-enclosed bay.

Functional-Segment Activity Coefficient Model. 1. Model Formulation

At present, at least for engineering purposes, the most successful predictive models for activity coefficients are those based on functional groups such as UNIFAC and its variants. While these models require large amounts of experimental data, the ones based on COSMO-RS require the calibration of a small set of universal parameters. However, the resolution required by many engineering tasks is usually higher than that obtained by COSMO-RS models. Thus, in this work, a novel functional-segment activity coefficient (F-SAC) model is proposed. This new model is also based on the concept of functional groups, but the interaction energy between groups comes from the COSMO-RS theory. The model parameters were calibrated for 21 groups and 43 subgroups by using infinite dilution activity coefficient (IDAC) data only. Only non-hydrogen bonding mixtures were investigated while associating mixtures are studied in an accompanying paper. For the considered IDAC data set, the F-SAC fit was superior to the predictions ob...

Seasonal dynamics of phytoplankton functional groups and its relationship with the environment in river: a case study in northeast China

In this study, the concept of functional groups was applied for the first time to the seasonal dynamics of the phytoplankton community of Mudanjiang River (northeast China). The environmental variables as well as the phytoplankton communities were determined in 2007. The river showed strong seasonal fluctuations in water physical and chemical condition. A total of 11 phytoplankton functional groups (C, D, E, J, MP, P, T, TB, W1, X2 and Y) were identified that included 30 species. Groups C (Asterionella formosa and Cyclotella meneghiniana), MP (Cocconeis placentula, Cymatopleara solea, Diatoma vulgare, Ochromonas fragilis, Pinnularia major and Ulothrix variabilis), P (Fragilaria capucina, Fragilaris sp., Aulacoseira granulate and Aulacoseira granulate var. angustissima), TB (Aulacoseira varians and Navicula exigua, Navicula radiosa), X2 (Chlamydomonas sp.) and Y (Chroomonas acuta, Cryptomonas ovata, and Cryptomonas sp.) were the dominant groups during the study period. Mudanjiang River phytoplankton functional groups exhibited a noticeable seasonality in which group Y was predominant in the winter and spring associated with greater soluble reactive phosphorus availability, group MP in the summer associated with ammonium-nitrogen availability, and group P in autumn associated with greater transparency. This study underscores the usefulness of functional groups in studying phytoplankton dynamics in this river, in which phytoplankton dynamics can be significantly affected by tourism.

Phytoplankton functional groups as indicators of human impacts along the River Loire (France)

The phytoplankton functional group concept is successfully used to assess ecological status in lakes (Q index), and also provides a method for lotic ecosystems (Q(r) index). Here, we examine the Q(r) composition metric to demonstrate local to regional scale human effects on natural distribution of phytoplankton along the River Loire. Distribution of phytoplankton functional groups coupled with chemical and physical parameters are described at whole river scale (19 stations, between March and November 2009). Natural longitudinal changes were reflected by the switch from benthic Pennales (TB) towards meroplanktic greens (J) via unicellular centric diatoms (D/C). While upstream human pressure was mostly associated to species indicating eutrophic, stagnant environments (coda P, M, H1, Y), downstream attenuation of the Q(r) reflected enriched, shallow environments with prolonged residence time (coda J, X2, X1). Occurrence of minimum Q(r) index values were synchronized to late summer, but the longer was the distance from the source, the earlier was the seasonal decrease of Q(r). Increasing downstream co-dominance of codon F evidenced an ascending light availability in summer. The longitudinal distribution of functional groups allowed us to conclude that functional diversity might be able to sign human-affected richness, while simply species diversity does not.

Plant functional group classifications and a generalized hierarchical framework of plant functional traits

The plant functional group concept has been proven to be an excellent research framework for investigating the linkages between ecosystem functions and plant biodiversity. The large number of plant functional group classifications however makes it difficult to compare data from different studies and draw general conclusions. In this article, we briefly review the major plant functional group classifications, and then propose a generalized hierarchical framework that incorporates plant functional traits ranging from the molecular to the biospherical level, and operating on varying spatial/temporal/disturbance scales for in-depth studies of the relationship between plant biodiversity and ecosystem characteristics. This framework may help policy makers formulate better ecological conservation and restoration plans.

Construction of Fluorescent Probes Via Protection/Deprotection of Functional Groups: A Ratiometric Fluorescent Probe for Cu2+

Herein a ratiometric fluorescent Cu(2+) probe was rationally constructed in a straightforward manner with the concept of aldehyde group protection/deprotection. The probe showed a ratiometric fluorescent response to Cu(2+) with a large emission wavelength shift (>100 nm) and displayed high selectivity for Cu(2+) over other metal ions due to distinct deprotection conditions. In addition, a Cu(2+)-promoted dethioacetalization mechanism was proposed.

Reaction-MQL: Line Notation for Functional Transformation

Representation of chemical reactions is pivotal for different purposes in cheminformatics. We present an extension of the molecular query language (MQL), which combines readable style with meaningful rules for string representation of reactions and unambiguous product formation. The concept of functional groups is used to describe the transformations. Functional groups are defined in terms of substructure queries and are processed by graph transformations. Molecular educt graphs are transformed by application of beginning-, end-, and reaction-matrices to obtain the product graph without consideration of stereochemistry. Both directions of a transformation are possible. We implemented the concept of Reaction-MQL in Java employing the Chemistry Development Kit.