Role Of Individual Species Research Articles

Bisphosphonate-Related Osteonecrosis of the Jaw and Oral Microbiome: Clinical Risk Factors, Pathophysiology and Treatment Options.

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) represents a serious health condition, impacting the lives of many patients worldwide. The condition challenges clinical care due to its complex etiology and limited therapeutic options. A thorough understanding of the pathophysiological and patient-related factors that promote disease development is essential. Recently, the oral microbiome has been implicated as a potential driver and modulating factor of BRONJ by several studies. Modern genomic sequencing methods have provided a wealth of data on the microbial composition of BRONJ lesions; however, the role of individual species in the process of disease development remains elusive. A comprehensive PubMed search was conducted to identify relevant studies on the microbiome of BRONJ patients using the terms "microbiome", "osteonecrosis of the jaws", and "bisphosphonates". Studies focusing on symptoms, epidemiology, pathophysiology, risk factors, and treatment options were included. The principal risk factors for BRONJ are tooth extraction, surgical procedures, and the administration of high doses of bisphosphonates. Importantly, the oral microbiome plays a significant role in the progression of the disease. Several studies have identified alterations of microbial composition in BRONJ lesions. However, there is no consensus regarding bacterial species that are associated with BRONJ across studies. The bacterial genera typically found include Actinomyces, Fusobacterium, and Streptococcus. It is postulated that these microbes contribute to the pathogenesis of BRONJ by promoting inflammation and disrupting normal bone remodeling processes. Current therapeutic approaches are disease-stage-specific and the necessity for more effective treatment strategies remains. This review examines the potential causes of and therapeutic approaches to BRONJ, highlighting the link between microbial colonization and BRONJ development. Future research should seek to more thoroughly investigate the interactions between bisphosphonates, the oral microbiome, and the immune system in order to develop targeted therapies.

Long-term exposure to PM2.5 species and all-cause mortality among Medicare patients using mixtures analyses

BackgroundThe relationship between long-term exposure to PM2.5 and mortality is well-established; however, the role of individual species is less understood. ObjectivesIn this study, we assess the overall effect of long-term exposure to PM2.5 as a mixture of species and identify the most harmful of those species while controlling for the others. MethodsWe looked at changes in mortality among Medicare participants 65 years of age or older from 2000 to 2018 in response to changes in annual levels of 15 PM2.5 components, namely: organic carbon, elemental carbon, nickel, lead, zinc, sulfate, potassium, vanadium, nitrate, silicon, copper, iron, ammonium, calcium, and bromine. Data on exposure were derived from high-resolution, spatio-temporal models which were then aggregated to ZIP code. We used the rate of deaths in each ZIP code per year as the outcome of interest. Covariates included demographic, temperature, socioeconomic, and access-to-care variables. We used a mixtures approach, a weighted quantile sum, to analyze the joint effects of PM2.5 species on mortality. We further looked at the effects of the components when PM2.5 mass levels were at concentrations below 8 μg/m3, and effect modification by sex, race, Medicaid status, and Census division. ResultsWe found that for each decile increase in the levels of the PM2.5 mixture, the rate of all-cause mortality increased by 1.4% (95% CI: 1.3%–1.4%), the rate of cardiovascular mortality increased by 2.1% (95% CI: 2.0%–2.2%), and the rate of respiratory mortality increased by 1.7% (95% CI: 1.5%–1.9%). These effects estimates remained significant and slightly higher when we restricted to lower concentrations. The highest weights for harmful effects were due to organic carbon, nickel, zinc, sulfate, and vanadium. ConclusionsLong-term exposure to PM2.5 species, as a mixture, increased the risk of all-cause, cardiovascular, and respiratory mortality.

Intensive grazing alters the diversity, composition and structure of plant-pollinator interaction networks in Central European grasslands.

Complex socio-economic, political and demographic factors have driven the increased conversion of Europe’s semi-natural grasslands to intensive pastures. This trend is particularly strong in some of the most biodiverse regions of the continent, such as Central and Eastern Europe. Intensive grazing is known to decrease species diversity and alter the composition of plant and insect communities. Comparatively little is known, however, about how intensive grazing influences plant functional traits related to pollination and the structure of plant-pollinator interactions. In traditional hay meadows and intensive pastures in Central Europe, we contrasted the taxonomic and functional group diversity and composition, the structure of plant-pollinator interactions and the roles of individual species in networks. We found mostly lower taxonomic and functional diversity of plants and insects in intensive pastures, as well as strong compositional differences among the two grassland management types. Intensive pastures were dominated by a single plant with a specialized flower structure that is only accessible to a few pollinator groups. As a result, intensive pastures have lower diversity and specificity of interactions, higher amount of resource overlap, more uniform interaction strength and lower network modularity. These findings stand in contrast to studies in which plants with more generalized flower traits dominated pastures. Our results thus highlight the importance of the functional traits of dominant species in mediating the consequences of intensive pasture management on plant-pollinator networks. These findings could further contribute to strategies aimed at mitigating the impact of intensive grazing on plant and pollinator communities.

Functional structure of European forest beetle communities is enhanced by rare species

Biodiverse communities have been shown to sustain high levels of multifunctionality and thus a loss of species likely negatively impacts ecosystem functions. For most taxa, however, roles of individual species are poorly known. Rare species, often most likely to go extinct, may have unique traits and functional roles. Alternatively, rare species may be functionally redundant, such that their loss would not disrupt ecosystem functions. We quantified the functional role of rare species by using captures of wood-living (saproxylic) beetle species, combined with recent databases of morphological and ecological traits, from three regions in central and northern Europe. Using a rarity index based on species' local abundance, geographic range, and habitat breadth, we used local and regional species removal simulations to examine the contributions of both the rarest and the most common beetle species to three measures of community functional structure: functional richness, functional specialization, and functional originality. Both regionally and locally, all three measures declined more rapidly when rare species were removed than under common (or random) species removal scenarios. These consistent patterns across scales and among forest types give evidence that rare species provide unique functional contributions, and their loss may disproportionately impact ecosystem functions. This implies that conservation measures targeting rare and endangered species, such as preserving intact forests with dead wood and mature trees, can provide broader ecosystem-level benefits. Experimental research linking functional structure to ecosystem processes should be prioritized to increase understanding of the functional consequences of species loss and to develop more effective conservation strategies.

Features of insect species diversityin the forest plantings disturbed by anthropogenic impact

Insects are universal objects for monitoring biogeocenoses. Wide distribution, close connection with various components of the environment and the abundance of individual species in disturbed ecosystems, the variety of responses to anthropogenic impacts, quick response to changes in the quality of the environment, as well as there is a clear correlation between the level of exposure and the degree of manifestation of the response time they make it possible to use insects as indicators. Green spaces are an important environmental protection and environmental-forming factor of the urban environment, which determines changes in the composition and structure of entomological complexes. At the same time, plantings of different types and environmental categories are in different conditions in relation to air pollution, that what determines the features of biodiversity and the balance of the population structure. Among the most significant among them are the exhaust gases of motor vehicles, various chemicals used to combat icing of the roadway in winter, as well as the selective destruction of weed vegetation within the decorative design of highways, etc. The need to study the responses to environmental pollution, manifested in changes in the composition and structure of entomofauna, the dynamics of the number and the change in the role of individual species in the transformed territories determines the direction of this study. The analysis of insect responses at the species level allows us to identify the consequences of the transformation of biocenoses, changes in faunal abundance, the structure of dominance and, as a result, determines the stability of ecosystems.

Common spatial patterns of trees in various tropical forests: Small trees are associated with increased diversity at small spatial scales.

Tropical forests are notable for their high species diversity, even on small spatial scales, and right‐skewed species and size abundance distributions. The role of individual species as drivers of the spatial organization of diversity in these forests has been explained by several hypotheses and processes, for example, stochastic dilution, negative density dependence, or gap dynamics. These processes leave a signature in spatial distribution of small trees, particularly in the vicinity of large trees, likely having stronger effects on their neighbors. We are exploring species diversity patterns within the framework of various diversity‐generating hypotheses using individual species–area relationships. We used the data from three tropical forest plots (Wanang—Papua New Guinea, Barro Colorado Island—Panama, and Sinharaja—Sri Lanka) and included also the saplings (DBH ≥ 1 cm). Resulting cross‐size patterns of species richness and evenness reflect the dynamics of saplings affected by the distribution of large trees. When all individuals with DBH ≥1 cm are included, ~50% of all tree species from the 25‐ or 50‐ha plot can be found within 35 m radius of an individual tree. For all trees, 72%–78% of species were identified as species richness accumulators, having more species present in their surroundings than expected by null models. This pattern was driven by small trees as the analysis of DBH >10 cm trees showed much lower proportion of accumulators, 14%–65% of species identified as richness repellers and had low richness of surrounding small trees. Only 11%–26% of species had lower species evenness than was expected by null models. High proportions of species richness accumulators were probably due to gap dynamics and support Janzen–Connell hypothesis driven by competition or top‐down control by pathogens and herbivores. Observed species diversity patterns show the importance of including small tree size classes in analyses of the spatial organization of diversity.

Seed Dispersal by Primates in Asian Habitats: From Species, to Communities, to Conservation

Primates are among the most important seed dispersers in the habitats they occupy. Understanding the extent of, and gaps in, our knowledge of seed dispersal by Asian primates is essential, because many of these primates are extremely vulnerable to anthropogenic disturbance. In this review, I show how initial studies focused on the role of individual species in seed dispersal have expanded more recently to consider their role in the wider frugivore community. There are five functional groups of primate seed dispersers in Asia; most of our information comes from the (usually) highly frugivorous macaques and gibbons, while our understanding of the roles played by orangutans and, especially, colobines and lorises remains rudimentary. Preliminary community-wide studies suggest a pivotal role for gibbons and macaques in frugivore communities, with higher dispersal overlap with other mammals than with birds. The gaps in our knowledge are plentiful, however, including understanding fruit selection in detail, determining how seed dispersal roles might change across different habitats, evaluating the balance between mutualisms and antagonisms in orangutans and macaques, describing postdispersal processes, and documenting how habitats are impacted by changes in primate abundance and behavior.

Metabolic pathway and role of individual species in the bacterial consortium for biodegradation of azo dye: A biocalorimetric investigation

In this study, an attempt was made to investigate the functional role and metabolic behaviour of the monoculture (Staphylococcus lentus (SL), Bacillus flexus (BF) and Pseudomonas aeruginosa (PA)) in the bacterial biocenosis for biotransformation of an azo dye. The power-time profile obtained from consortia depicted three distinct peaks, which correlated well with the individual bacterial growth (PA > SL > BF), indicating the synergistic relation and division of labour in the biocenosis. The heat release pattern was used to identify the sequential behaviour of microbial consortia in real time. Yield calculation based on total heat liberated to the complete substrate utilization Y (Q/S) for PA, SL, and BF were 15.99, 16.68, 7.32 kJ/L respectively. Similarly, the oxy calorific values Y (Q/O) for the above species are respectively 386, 375, 440 kJ/mol and indicates the aerobic nature of microorganism employed. Further, the metabolome produced during the biotransformation were identified using Gas Chromatography-Mass Spectrometry (GC-MS), based on which a plausible pathway was predicted. The abundant metabolites were palmitic acid (m/z = 256) and diethyl phthalate (m/z = 222.2). The abundance of diethyl phthalate was much lesser in the consortia compared to the monoculture. Thus, the biocalorimetric heat yield calculation along with the stoichiometry and plausible pathway based biochemical elucidation provides a mechanistic basis for understanding the azo-dye biotransformation by the monocultures in consortia.

Peculiarities of migration and accumulation of heavy metals in the system «ground-plant» by the example of the National natural park «Beloberezhye Svyatoslava»

Peculiarities of migration and accumulation of heavy metals in the system «ground-plant» by the example of the National natural park «Beloberezhye Svyatoslava»

Predominance and geo-mapping of avian influenza H5N1 in poultry sectors in Egypt.

Highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype has been enzootic in the Egyptian poultry with significant human infections since 2008. This work evaluates the epidemiological and virological information from February 2006 to May 2015 in spatial and temporal terms. Only data with confirmed HPAI H5N1 sub-type were collected, and matched with the epidemiological data from various spatially and temporally-dispersed surveillances implemented between 2006 and 2015. Spatio-temporal analysis was conducted on a total of 3338 confirmed H5N1 HPAI poultry disease outbreaks and outputs described based on transmission patterns, poultry species, production types affected, trade, geographic and temporal distributions in Egypt. The H5N1 virus persists in the Egyptian poultry displaying a seasonal pattern with peak prevalence between January and March. There was no specific geographic pattern, but chickens and ducks were more affected. However, relatively higher disease incidences were recorded in the Nile Delta. Phylogenetic studies of the haemagglutinin gene sequences of H5N1 viruses indicated that multiple clusters circulated between 2006 and 2015, with significant deviations in circulation. Epidemiological dynamics of HPAI has changed with the origins of majority of outbreaks shifted to household poultry. The persistence of HPAI H5N1 in poultry with recurrent and sporadic infections in humans can influence virus evolution spatio-temporally. Household poultry plays significant roles in the H5N1 virus transmission to poultry and humans, but the role of commercial poultry needs further clarifications. While poultry trading supports the persistence and transmission of H5N1, the role of individual species may warrant further investigation. Surveillance activities, applying a multi-sectoral approach, are recommended.

Retention of Atmospheric Particulate by Three Woody Ornamental Species in Santiago, Chile

It is traditionally accepted that urban vegetation contributes to improve air quality by intercepting and retaining the particulate matter. Although the mitigating role of plants has been recognized by several studies, the role of individual species is still poorly understood. This is particularly important in cities like Santiago (Chile), which has high levels of atmospheric particulate and also has high plant species diversity. In this study, we evaluated the retention of atmospheric particles by three widely distributed ornamental species (Nerium oleander, Pittosporum tobira, and Ligustrum lucidum) in Santiago. For this proposal, we took leaf samples in different sampling points across the city which vary in their concentration of atmospheric particulate. Samples were taken 12 and 16 days after a rainfall episode that washed the leaves of plants in the sampling sites. In the laboratory, leaves were washed to recover the surface retained particles that were collected to determine its mass gravimetrically. With this information, we estimated the foliar retention (mass of particulate matter retained in the foliar surface) and daily retention efficiency (mass of particulate matter retained in the foliar surface per day). We found that foliar retention and daily retention efficiency varied significantly between the studied species. The leaves of N. oleander retained 8.2 g m−2 of particulate matter on average, those of P. tobira 6.1 g m−2, and those of L. lucidum 3.9 g m−2; meanwhile, the daily retention efficiencies of particulate matter were 0.6, 0.4, and 0.3 g m−2 day−1 for N. oleander, P. tobira, and L. lucidum, respectively. These results suggest that the studied species retain atmospheric particulate matter differentially in Santiago. These results can be attributed to differences on leaf surface characteristics. The recognition of the most efficient species in the retention of the atmospheric particulate matter can help to decide which species can be used to improve the air quality in the city.

Variation in viral shedding patterns between different wild bird species infected experimentally with low-pathogenicity avian influenza viruses that originated from wild birds

The prevalence of infection with avian influenza (AI) virus varies significantly between taxonomic Orders and even between species within the same Order. The current understanding of AI infection and virus shedding parameters in wild birds is limited and largely based on trials conducted in mallards (Anas platyrhynchos). The objective of the present study was to provide experimental data to examine species-related differences in susceptibility and viral shedding associated with wild bird-origin low-pathogenicity avian influenza (LPAI) viruses in multiple duck species and gulls. Thus mallards, redheads (Aythya americana), wood ducks (Aix sponsa), and laughing gulls (Leucophaeus atricilla) were inoculated experimentally with three wild mallard-origin LPAI viruses representing multiple subtypes. Variation in susceptibility and patterns of viral shedding associated with LPAI virus infection was evident between the duck and gull species. Consistent with the literature, mallards excreted virus predominantly via the gastrointestinal tract. In wood ducks, redheads, and laughing gulls, AI virus was detected more often in oropharyngeal swabs than cloacal swabs. The results of this study suggest that LPAI shedding varies between taxonomically related avian species. Such differences may be important for understanding the potential role of individual species in the transmission and maintenance of LPAI viruses and may have implications for improving sampling strategies for LPAI detection. Additional comparative studies, which include LPAI viruses originating from non-mallard species, are necessary to further characterize these infections in wild avian species other than mallards and provide a mechanism to explain these differences in viral excretion.

The Starting Lineup: Key Microbial Players in Intestinal Immunity and Homeostasis

The complexity of microbiota inhabiting the intestine is increasingly apparent. Delicate balance of numerous bacterial species can affect development of the immune system, how susceptible a host is to pathogenic organisms, and the auto-inflammatory state of the host. In the last decade, with the increased use of germ-free mice, gnotobiotic mice, and animal models in which a germ-free animal has been colonized with a foreign microbiota such as humanized mice, it has been possible to delineate relationships that specific bacteria have with the host immune system and to show what role they may play in overall host health. These models have not only allowed us to tease out the roles of individual species, but have also allowed the discovery and characterization of functionally unknown organisms. For example, segmented filamentous bacteria (SFB) have been shown to play a vital role in expansion of IL-17 producing cells. Prior to linking their key role in immune system development, little was known about these organisms. Bacteroides fragilis can rescue some of the immune defects of gnotobiotic mice after mono-colonization and have anti-inflammatory properties that can alleviate colitis and experimental allergic encephalitis in murine models. Additionally, Clostridium species have most recently been shown to expand regulatory T-cell populations leading to anti-inflammatory conditions. This review will highlight and summarize some of the major findings within the last decade concerning the role of select groups of bacteria including SFB, Clostridium, Bacteroides, Bifidobacterium, and Lactobacillus, and their impact on host mucosal immune systems.

Rivets or bolts? When single species count in the function of temperate rocky reef communities

There is considerable controversy about the role of individual species in ecosystem functioning. Most models stress the role of species richness and diversity in ecosystem function, but it is also recognised that individual species or functionally similar species can play prominent roles in assessments of function. There have been relatively few tests of functional replacement by similar species in the marine environment. On intertidal reef platforms in southern New Zealand, six species of fucoid algae co-occur. Two of these, Cystophora torulosa and Hormosira banksii, have extensive cover in the mid-tidal zone. These species were removed from their areas of dominance in the mid-tidal zone at two sites and followed for several years to determine how resilient they are to disturbance, what processes determine functional recovery, the role of the dominant grazer, the gastropod Turbo smaragdus, in the recovery process, and whether there is functional replacement of species. In the C. torulosa removal experiment, H. banksii recruited rapidly into removal treatments within the first year at one site, but this took a year longer at the other site. A press removal of C. torulosa developed almost 100% cover of H. banksii after 3 years, but only at one site. In the pulse treatment, there was a mixed stand of the two species after 3–4 years. In the H. banksii removal experiment, there was no functional replacement by other species. The rate of recovery for H. banksii was variable. Bare space increased following canopy removal, particularly on the higher shore treatment at one site, because of the burn-off of newly exposed turfing coralline algae, which had not fully recovered by the end of the experiment. After 10 months, there were 20–40% fewer species in the removal plots in both experiments than in controls. T. smaragdus grazing had great effects on ephemeral algae, but not on the fucoids. The conclusion is that these fucoid species have no functional equivalents in their areas of dominance. They are the autogenic engineers or foundation species on which most other species in their communities rely. There is little buffering overall in these mid-shore zones should these species be lost or severely reduced in abundance. They are, therefore, key species in the function of the intertidal system and must be understood if the functioning of these areas is to be managed effectively. These results are discussed in the spirit of this festschrift for AJ Underwood.

Molecular diagnosis and equine parasitology

The future implementation of improved and sustainable control strategies for the major equine parasites will be dependent on a greater insight into their basic biology, pathogenicity and epidemiology together with an enhanced ability for accurate diagnosis. This paper will provide a review of the current molecular methods under development for the detection of equine parasites and their application to current scientific questions. In particular, the strongyles are recognised as important pathogens of horses and recent advances made in the study of this parasitic group at the single species level will be addressed. The ribosomal (r)DNA region of the parasite genome has been employed to distinguish between closely related species. Molecular probes designed to this target region were used in combination with PCR technology to allow the identification of individual species within mixed infections. They have been applied to all parasite stages to look at the role of individual species in natural infection, disease and drug resistance. Similar techniques have been developed to detect other equine parasites and these will also be discussed. Further opportunities for employing existing techniques and the need for new diagnostic tools will be highlighted.

03/02182 Hydrogenation of phenanthrene in the presence of Ni catalyst. Thermal dehydrogenation of hydrophenanthrenes and role of individual species in hydrogen transfers for coal liquefaction: Nuzzi, M. and Marcandalli, B. Fuel Processing Technology, 2003, 80, (1), 3–45

03/02182 Hydrogenation of phenanthrene in the presence of Ni catalyst. Thermal dehydrogenation of hydrophenanthrenes and role of individual species in hydrogen transfers for coal liquefaction: Nuzzi, M. and Marcandalli, B. Fuel Processing Technology, 2003, 80, (1), 3–45

Hydrogenation of phenanthrene in the presence of Ni catalyst. Thermal dehydrogenation of hydrophenanthrenes and role of individual species in hydrogen transfers for coal liquefaction

Mixtures of phenanthrene (P) and hydrophenanthrenes (HPs) of increasing hydrogenation degree (H 2P, H 4P, H 8Ps, H 14Ps) were obtained by hydrogenation of P under kinetic control conditions on Ni catalyst at 292 °C and 315 °C under constant hydrogen pressure (7.1–7.8 MPa) for reaction times up to 96 min. Thermal treatments (400 °C, 60 min) of the final mixtures have permitted to define the roles of individual molecular species (in particular H 2P and s-H 8P) in bimolecular reactions of H-exchange and disproportionation and in unimolecular reactions of isomerization and fragmentation connected to the thermal dehydrogenation. H 8Ps, as overhydrogenated donor species, were further examined with regard to the bimolecular reactions at higher temperature (484 °C) and shorter reaction times (10 min) in the presence of P added as coal model.

Relationship between Productivity, and Species and Functional Group Diversity in Grazed and Non-Grazed Pampas Grassland

Most hypotheses addressing the effect of diversity on ecosystem function indicate the occurrence of higher process rates with increasing diversity, and only diverge in the shape of the function depending on their assumptions about the role of individual species and functional groups. Contrarily to these predictions, we show that grazing of the Flooding Pampas grasslands increased species richness, but drastically reduced above ground net primary production, even when communities with similar initial biomass were compared. Grazing increased species richness through the addition of a number of exotic forbs, without reducing the richness and cover of the native flora. Since these forbs were essentially cool-season species, and also because their introduction has led to the displacement of warm-season grasses from dominant to subordinate positions in the community, grazing not only decreased productivity, but also shifted its seasonality towards the cool season. These results suggest that species diversity and/or richness alone are poor predictors of above-ground primary production. Therefore, models that relate productivity to diversity should take into account the relative abundance and identity of species that are added or deleted by the specific disturbances that modify diversity.