Loss Of Species Diversity Research Articles

Major specialized natural products from the endangered plant Heptacodium miconioides, potential medicinal uses and insights into its longstanding unresolved systematic classification

A comprehensive phytochemical investigation of the flower buds and leaves/twigs of Heptacodium miconioides, a cultivated ornamental plant native to China and categorized as ‘vulnerable’, has led to the isolation of 45 structurally diverse compounds, which comprise 18 phenylpropanoids (1–4, 7–20), 11 pentacyclic triterpenoids (5, 6, 21–29), eight secoiridoid glycosides (30–37), three quinic acid derivatives (38–40), and a few miscellaneous components (41–45). Among them, (+)-α-intermedianol (1), (+)-holophyllol A (2), and (−)-pseudolarkaemin A (3) represent previously unreported enantiomeric lignans, while (+)-7′(R)-hydroxymatairesinol (4) is an undescribed naturally occurring lignan. Heptacoacids A (5) and B (6) are undescribed 24-nor-urs-28-oic acid derivatives. Their chemical structures were determined by 2D-NMR, supplemented by evidence from specific rotations and circular dichroism spectra. Given the uncertainty surrounding the systematic position of Heptacodium, integrative taxonomy (ITA), a method utilized to define contentious species, is applied. Chemotaxonomy, a vital aspect of ITA, becomes significant. By employing hierarchical clustering analysis (HCA) and syntenic pattern analysis methods, a taxonomic examination based on the major specialized natural products from the flower buds of H. miconioides and two other Caprifoliaceae plants (i.e., Lonicera japonica and Abelia × grandiflora) could offer enhanced understanding of the systematic placement of Heptacodium. Additionally, compounds 39 and 40 displayed remarkable inhibitory activities against ATP-citrate lyase (ACL), with IC50 values of 0.11 and 1.10 μM, respectively. In summary, the discovery of medical properties and refining systematic classification can establish a sturdy groundwork for conservation efforts aimed at mitigating species diversity loss while addressing human diseases.

Intraspecific variation in Janzen-Connell effect is mediated by stress and plant-soil feedbacks.

Janzen-Connell (JC) effects, hypothesized to be partially driven by negative plant-soil feedbacks (PSFs), are considered to be a key mechanism that regulates tropical forest plant diversity and coexistence. However, intraspecific variation in JC effects may weaken this mechanism, with the strength of PSFs being a potentially key variable process. We conducted a manipulated experiment with seedlings from two populations of Pometia pinnata (Sapindaceae), a tropical tree species in southwest China. We aimed to measure the intraspecific difference in PSF magnitude caused by inoculating the soil from different P. pinnata source populations and growing seedlings under differing light intensity and water availability treatments, and at varying plant densities. We found negative PSFs for both populations with the inoculum soil originating from the same sites, but PSFs differed significantly with the inoculum soil from different sites. PSF strength responded differently to biotic and abiotic drivers; PSF strength was weaker in low moisture and high light treatments than in high moisture and low light treatments. Our study documents intraspecific variation in JC effects: specifically, P. pinnata have less defenses to their natively-sourced soil, but are more defensive to the soil feedbacks from soil sourced from other populations. Our results imply that drought and light intensity tended to weaken JC effects, which may result in loss of species diversity with climate change.

Species Diversity and Habitat Fragmentation Per Se: The Influence of Local Extinctions and Species Clustering.

AbstractAnthropogenic fragmentation of habitat is considered to be a critical factor contributing to the decline of species. However, a general consensus on the degree to which habitat loss and what has been called "habitat fragmentation per se" contribute to the loss of species diversity has not yet emerged. For empirical and theoretical reasons the topic has recently attracted renewed attention, thus reviving the "single large or several small" (SLOSS) debate. To study the effect of fragmentation per se, we use a spatially explicit and continuous, competitively neutral simulation model with immigration from a regional pool. The model accounts for the influence of ecological drift and intrafragment species clustering (due to limited dispersal) on local (plot) and global (landscape) diversity. We find that fragmentation increases global diversity but decreases local diversity, prominently so if fragments become more isolated. Cluster formation is a key mechanism reducing local diversity. By adding external disturbance events that lead to the occasional extinction of entire communities in habitat fragments, we show that the combined effect of such extinctions and cluster formation can create nonlinear interactive effects of fragmentation and fragment isolation on diversity patterns. We conclude that while in most cases fragmentation will decrease local and increase landscape diversity, universal predictions concerning the SLOSS debate should be taken with care.

Diversity begets stability: Sublinear growth and competitive coexistence across ecosystems.

The worldwide loss of species diversity brings urgency to understanding how diverse ecosystems maintain stability. Whereas early ecological ideas and classic observations suggested that stability increases with diversity, ecological theory makes the opposite prediction, leading to the long-standing "diversity-stability debate." Here, we show that this puzzle can be resolved if growth scales as a sublinear power law with biomass (exponent <1), exhibiting a form of population self-regulation analogous to models of individual ontogeny. We show that competitive interactions among populations with sublinear growth do not lead to exclusion, as occurs with logistic growth, but instead promote stability at higher diversity. Our model realigns theory with classic observations and predicts large-scale macroecological patterns. However, it makes an unsettling prediction: Biodiversity loss may accelerate the destabilization of ecosystems.

Loss of functional diversity rather than species diversity of pollinators decreases community‐wide trait matching and pollination function

Abstract Loss of animal species and functional diversity can degrade ecosystem functions and services in plant–animal mutualistic networks, but their relative effects have rarely been previously examined in natural communities. Contrary to previously published theoretical results, under natural conditions, changes in pollinator functional niches caused by species and functional diversity losses are dynamic and often unpredictable. The lack of studies on natural networks limits our ability to predict future effects of decreasing pollinator diversity on wild and cultivated plants. We quantitatively evaluated the relative effects of pollinator species and functional diversity loss on plant–pollinator trait matching and pollination success across 40 spatiotemporally variable coastal networks. We found that low pollinator functional diversity (low abundance of long‐tongued pollinators) reduced community‐level plant functional specialization and trait matching between flowers and pollinators by reducing functional floral‐niche partitioning among pollinators. In contrast, pollinator species diversity did not influence community‐level trait matching. Furthermore, decreasing community‐level trait matching had a negative effect on community‐level plant pollination success, regardless of flower morphology. The present study demonstrated that pollinator functional diversity loss, rather than species diversity loss, was the main factor contributing to pollination functional loss in the plant–pollinator networks studied. We also demonstrated the importance of assessing functional aspects of plant–pollinator networks to evaluate community‐level pollination functional loss under global pollinator decline. Read the free Plain Language Summary for this article on the Journal blog.

ASSESSMENT OF FOREST VEGETATION POTENTIAL OF RECLAIMED AREAS AFTER ILMENITE MINING USING THE REMOTE EARTH SENSING METHOD

The mining of ilmenite has irreversible negative environmental impacts on the ecosystem of the area where mining companies operate. First of all, it leads to disturbance of the soil and vegetation layer, changes in the natural landscape, formation of depression sinkholes, which causes changes in water flow and water distribution in the mining area, lowering of groundwater levels, pollution of the atmosphere, soil and water bodies, and loss of species diversity of flora and fauna. In general, the mining process lasts for decades, during which time the territory is subject to irreversible changes and disturbances and requires high-quality restoration after the completion of ilmenite mining. The article suggests a methodology for assessing the forest vegetation potential of soils in areas disturbed by ilmenite mining using remote earth sensing (RES). Based on satellite images and spectral characteristics, we determined the parameters of soil type and moisture, as well as the vegetation and moisture index of the forest vegetation layer The results of the remote earth sensing were compared with the results of laboratory analyzes of soil samples from the territory operated by the branch of the Irshansk Mining and Processing Plant of PJSC UMCC. Normalized Difference Vegetation Index, Normalized Difference Moisture Index, soil type and moisture were calculated and identified using QGIS software from data obtained from free-access satellite images. The results showed that a combination of laboratory and remote sensing methods can be quite effective for studying areas disturbed by mining activities and the state of their recovery after reclamation.

The Restructuring of Ecological Networks by the Pleistocene Extinction

Most terrestrial large mammals went extinct on different continents at the end of the Pleistocene, between 50,000 and 10,000 years ago. Besides the loss in species diversity and the truncation of body mass distributions, those extinctions were even more impactful to interaction diversity. Along with each extinction, dozens of ecological interactions were lost, reorganizing species interaction networks, which attained species-poor configurations with low functional redundancy. Extinctions of most large herbivores impacted energy flow and the rates of nutrient cycling, reconfiguring ecosystem-level networks. Because large mammals have high mobility, their loss also shortened seed-dispersal distance and reduced nutrient diffusivity, disrupting spatial networks. This review examines the recent advances in understanding how different types of ecological networks have been restructured by megafaunal extinctions and how this reorganization affected ecosystem functions. ▪Megafaunal extinctions resulted in the loss of multiple ecological interactions in terrestrial systems.▪Interaction loss reshaped different types of ecological networks including food webs and spatial networks.▪The reorganization of ecological networks changed how terrestrial ecosystems are structured and function.

Understanding behavioral intention of landowners to promote wildlife richness and biodiversity in the Southern Great Plains

Ranchers have been conducting traditional management practices such as mono-species grazing and limited burning that focus on stocking rate maximization. This has resulted in negative environmental consequences such as woody plant encroachment, land use change, and species diversity loss. Recently, there has been a growing appreciation for alternative range management that simultaneously promotes biodiversity and agricultural productivity through fire and grazing interactions. The purpose of the study was to investigate the influence of landowner values, attitudes, and norms on their behavioral intention to adopt best management practices (BMPs) that enhance wildlife abundance in the southern Great Plains. The required data was generated through a mail survey following the Tailored Design method. We utilized the structural equation path model to construct two latent variables for norms and attitudes and analyzed the relationship of the latent variables with value orientations and behavioral intentions. The study results indicated that the attitudes had a significant positive relationship with biocentric (β = 0.15, p-value<0.05) and a negative relationship with anthropocentric (β = −0.259, p-value<0.05) value orientations, however, the relationship of value orientations was statistically insignificant with norms. Further, the results indicated that both norms (β = 0.404, p-value<0.05) and attitudes (β = 0.508, p-value<0.05) had a positive and statistically significant relation with ranchers’ intentions to increase wildlife abundance on their land. Study results emphasize the need for innovative communication and non-traditional outreach methods to educate rangeland owners on the importance of patch-burn grazing and other best management practices.

Does trade openness aggravate embodied species loss?: Evidence from the belt and road countries

Along with the evolution of the international division of labor, trade openness is increasingly affecting species diversity in a profound way, driving an accelerated loss of species diversity. However, current research rarely discusses the mechanism of action between the two. To fill this gap, this paper based on the input and output model quantified the trade-off between economic efficiency and species diversity in global supply chain by centering on a dynamic evolution of embodied species loss driven by trade openness. The results show that effect coefficients of trade openness on embodied species loss is positive which means trade openness exacerbates the level of species loss; Regression results distinguishing the stages of species loss show that increasing the level of trade openness can exacerbate species loss in samples with higher levels of loss. Heterogeneity analysis finds that increased trade openness in developing economies can exacerbate the rate of species loss. Mechanistic tests find that trade openness affects species loss mainly by enhancing the level of technological progress and mitigating the size of the labor force; Machine learning models reveal a nonlinear trend of trade openness on species loss. This paper proposes relevant policy implications: countries should correctly balance the relationship between trade openness and species loss, focus on optimizing the structure of import and export trade, and reduce species loss while improving the trade openness system.

Impacts of Forest Management on the Biodiversity and Sustainability of Carya dabieshanensis Forests

Natural secondary Carya dabieshanensis forests comprise the natural wealth of the Dabie Mountains, which maintain the ecological balance of this region and enhance the incomes of farmers. However, forest ecosystems are being increasingly challenged due to increasing long-term anthropogenic development and management. Elucidating the impacts of management intensity and duration on the diversity and stability of vegetation communities in natural secondary Carya dabieshanensis forests is of great significance toward achieving sustainable forest management. For this study, we compared the effects of three forest management intensities (no management (CK), extensive management (EM), and intensive management (IM)), and five management durations (0, 3, 8, 15, and 20 y) on species diversity and the stability of vegetation communities (trees, shrubs, and herbaceous layers) of a Carya dabieshanensis forest. Our results revealed that the diversity of the vegetation communities continued to decline following the onset of management activities. The diversity, dominance, evenness, and richness indices of the vegetation communities decreased by 53.37%–62.77%, 46.04%–59.17%, 32.58%–53.55%, and 50.18%–51.30%, respectively, after 20 y of forest management. Intensive management translated to species diversity loss more so than extensive management. All vegetation communities of the forest stands under study were generally unstable; however, the stability they did have was not at risk under greater management intensity and duration, and neither did greater species diversity enhance it. This study provides new evidence to support the non-synchronicity of species diversity and community stability in forest resident vegetation communities. Since the species diversity and structural composition of tree layers have a positive effect on community stability, so we suggest that both extensive and intensive forest lands need to retain or replant more tree species other than Carya dabieshanensis.

Artificial Propagation of Indigenous Ornamental Fish Species via Nutritional Manipulation for Stock Enhancement and Conservation as a Step towards Environmental Sustainability: A Review

Indigenous flora and fauna of a particular habitat greatly impacts the environment in maintaining an ecological balance and equilibrium for the normal functioning of the ecosystem as a whole. Native fishes play a major role and holds a major niche in the ecosystem which needs attention at the moment for their conservation and protection, failure of which may prove to be detrimental to the environment. The rapid developmental activities and industrialization taking place currently are leaving a negative impact upon the natural ecosystem. These activities are a major reason for loss of habitat, deterioration, pollution, and degradation. The ornamental fish industry is a budding industry in India and the indigenous fish fauna of the country offers a good market but unfortunately, so far, the requirements and demand are fulfilled from the natural stock through manual collection. Rigorous exploitation of these species may result into loss of species diversity or reduction of stock, provided, anthropogenic causes necessitated by development and industrialization are already acting upon the ecosystem. Therefore, in this review we will discuss the implementation of captive breeding techniques through nutritional manipulation for fish species so that the wild stock is not made vulnerable and instead, the same shall be enhanced through ranching. Though this technique offers certain limitations such as genetical quality compromise, inferior breeding performance etc., nevertheless it still is a major tool in conservational biology. The review will provide insights to researchers on how to achieve captive breeding success by manipulating nutritional component in fishes and eventually with the information made available in this document certain practical implementations may be necessitated which will help us move closer to the broader aspect of biodiversity conservation and sustainability.

Rarity of microalgae in macro, meso, and microhabitats

ABSTRACT Climate change and human-induced habitat degradations result in loss of species diversity in natural ecosystems. While the extinction of macroscopic organisms has been well documented in the scientific literature and public media, we have only limited knowledge on the loss of microscopic elements of the ecosystems. Because rarity coincides with the increased risk of extinction, we investigated the commonness and rarity of microalgae in the Pannonian ecoregion. We reviewed the published literature of microalgal research in Hungary over the last 140 years and created a species-by-site matrix containing 2489 algae species and 1145 localities. Analysing this dataset, we found that although the core-satellite hypothesis suggests a bimodal site occupancy distribution, microalgae displayed a unimodal pattern with a high number of rarely occurring species. We also demonstrated that the well-known negative relationship between body size of organisms and number of occupied habitats holds for microalgae. Rarity values of taxa have a phylogenetic signal indicating that in terms of rarity, closely related species (desmids, dinoflagellates, euglenophytes) show considerable similarities. The various habitat types showed differences in the number of rare taxa. Small- and medium-sized habitats (bog lakes, streams, oxbows) hosted the majority of rare species. These results highlight the conservation importance of small habitats in preserving microbial diversity.

Freshwater species diversity loss embodied in interprovincial hydroelectricity transmission with ecological network analysis.

A major strategy for addressing the imbalance in source-network-load distribution is interprovincial electricity transmission; however, this process also causes various environmental effects. Previous studies have mainly examined thermal power transmission, and few insights have been gained into the challenges hydroelectricity transmission poses for biodiversity conservation. Here, we innovatively incorporated the freshwater species diversity footprint into a hydropower environmental impact assessment, calculating the interprovincial transfer of freshwater species diversity embodied in hydroelectricity transmission. We proposed an evaluation model of an interprovincial hydroelectricity transmission network using freshwater species diversity as the ecological element and creatively identified significant nodes and paths of the network. Up to 28% of the transfer of freshwater species diversity was related to the demand for hydroelectricity consumption in Shanghai. 64% of the relationships in the hydroelectricity transmission network were implemented at the expense of ecological losses on one side. Shanghai and Sichuan provinces and some transmission lines related to them were significant nodes and paths for improving the overall status of the network. This research can help policymakers comprehend the challenges to freshwater species presented by interprovincial hydroelectricity transmission and serve as a reference for ecological compensation for hydropower development.

Study of mosquito (Culicidae) larvae and characterisation of water bodies in urban and periurban areas

Abstract Urbanisation has modified the distribution and community composition of mosquito species (Culicidae). Habitat disturbance may increase the risk of loss of species diversity and the occurrence of vector-borne diseases. Studies on the presence of larvae and the eco-physicochemical characteristics of water bodies near urban areas provide information on the risk of these diseases. In this study, the presence of larvae in different types of urban and periurban water bodies in Villahermosa City, Tabasco, Mexico was analysed. The eco-physicochemical characteristics of each collecting site were measured. A total of 67 528 larvae were collected, 1366 were identified to species, and 15 species were observed. Although Culex spp. were the most dominant species, Anopheles albimanus was the only species present in all habitats. Despite the large variability in the parameters measured (especially in physicochemical parameters; e.g., pH, electrical conductivity, total dissolved solids), differences were observed among the breeding sites. Weak correlations were found between eco-physicochemical parameters and species presence. Predators may have a major role in determining community processes in the region. Habitat disturbance may be responsible for eco-physicochemical variations altering mosquito community composition, resulting in the loss of endemic mosquito species and increasing the risk of vector-borne diseases in Villahermosa.

Climate overrides fencing and soil mineral nutrients to affect plant diversity and biomass of alpine grasslands across North Tibet.

Overgrazing and warming are thought to be responsible for the loss of species diversity, declined ecosystem productivity and soil nutrient availability of degraded grasslands on the Tibetan Plateau. Mineral elements in soils critically regulate plant individual's growth, performance, reproduction, and survival. However, it is still unclear whether plant species diversity and biomass production can be improved indirectly via the recovery of mineral element availability at topsoils of degraded grasslands, via grazing exclusion by fencing for years. To answer this question, we measured plant species richness, Shannow-Wiener index, aboveground biomass, and mineral element contents of Ca, Cu, Fe, Mg, Mn, Zn, K and P at the top-layer (0 - 10 cm) soils at 15 pairs of fenced vs grazed matched sites from alpine meadows (n = 5), alpine steppes (n = 6), and desert-steppes (n = 4) across North Tibet. Our results showed that fencing only reduced the Shannon-Wiener index of alpine meadows, and did not alter aboveground biomass, species richness, and soil mineral contents within each grassland type, compared to adjacent open sites grazed by domestic livestock. Aboveground biomass first decreased and then increased along with the gradient of increasing Ca content but did not show any clear relationship with other mineral elements across the three different alpine grassland types. More than 45% of the variance in plant diversity indices and aboveground biomass across North Tibet can be explained by the sum precipitation during plant growing months. Structural equation modelling also confirmed that climatic variables could regulate biomass production directly and indirectly via soil mineral element (Ca) and plant diversity indices. Overall, the community structure and biomass production of alpine grasslands across North Tibet was weakly affected by fencing, compared to the robst climatic control. Therefore, medium-term livestock exclusion by fencing might have limited contribution to the recovery of ecosystem structure and functions of degraded alpine grasslands.

Climate and forest attributes influence above‐ground biomass of deciduous broadleaf forests in China

Abstract Forests provide a huge carbon pool, a substantial portion of which is stored in above‐ground biomass (AGB). Deciduous broadleaf forests in China are an essential component of global deciduous broadleaf forests, yet the impacts of climate and forest attributes on their AGB are not well understood. Using a comprehensive forest inventory database from 772 plots distributed across temperate and subtropical deciduous broadleaf forests in China (23.51°–42.53°N and 104.24°–128.27°E), we applied variance partitioning analysis, model selection analysis and structural equation models to explore how climate and forest attributes (species diversity, community‐level functional traits and stand structures) affect AGB in different climatic forests (semi‐arid forests, semi‐humid forests and humid forests). Community‐level functional traits and stand structures together explained a great portion of the variance in AGB. The effect of community‐level functional traits was greater than that of stand structures in semi‐arid forests and semi‐humid forests, but smaller in humid forests. Further analyses showed that community‐level maximum tree height, stem density and tree size inequality were important explanatory variables. Although climate and species diversity had minor effects, the direct positive effect of mean annual precipitation (MAP) was still important, especially in semi‐arid forests. Synthesis. Community‐level functional traits but not species diversity were key drivers of AGB, indicating that tree species diversity loss may not impair AGB substantially in deciduous broadleaf forests in China. Moreover, stand structures also had strong effects on AGB in both semi‐arid forests and humid forests, highlighting the importance of structural complexity. In addition, MAP had a direct positive effect on AGB in semi‐arid forests and semi‐humid forests, and a future increase in drought might potentially reduce carbon storage in these forests.

Phylogenetic diversity only weakly mitigates climate-change-driven biodiversity loss in insect communities.

To help address the underrepresentation of arthropods and Asian biodiversity from climate-change assessments, we carried out year-long, weekly sampling campaigns with Malaise traps at different elevations and latitudes in Gaoligongshan National Park in southwestern China. From these 623 samples, we barcoded 10,524 beetles and compared scenarios of climate-change-induced biodiversity loss, by designating seasonal, elevational, and latitudinal subsets of beetles as communities that plausibly could go extinct as a group, which we call "loss sets". The availability of a published mitochondrial-genome-based phylogeny of the Coleoptera allowed us to compare the loss of species diversity with and without accounting for phylogenetic relatedness. We hypothesised that phylogenetic relatedness would mitigate extinction, since the extinction of any loss set would result in the disappearance of all its species but only part of its evolutionary history, which is still extant in the remaining loss sets. We found different patterns of community clustering by season and latitude, depending on whether phylogenetic information was incorporated. However, accounting for phylogeny only slightly mitigated the amount of biodiversity loss under climate change scenarios, against our expectations: there is no phylogenetic "escape clause" for biodiversity conservation. We achieve the same results whether phylogenetic information was derived from the mitogenome phylogeny or from a de novo barcode-gene tree. We encourage interested researchers to use this data set to study lineage-specific community assembly patterns in conjunction with life-history traits and environmental covariates.

THE STATUS OF THE TERRESTRIAL PLANT SPECIES AVAILABLE IN HAMISI SUB-COUNTY, VIHIGA COUNTY, KENYA

Most of the earth’s ecosystems have been dramatically transformed through anthropogenic actions. Unfortunately, some of these transformations represent a loss of diversity rather than enriching it. Habitat loss due to large-scale conversion of land to agriculture and settlement, infrastructure establishment, the introduction of invasive species and overexploitation of biological resources are among the global key drivers of terrestrial plant species diversity loss all of which have their origin in human demands placed on the terrestrial ecosystems. In Vihiga County, Hamisi sub-county, the rate of terrestrial plant diversity decline has increased in the recent past due to human actions; however, little is known about the effects of anthropogenic activities on terrestrial plant species diversity. The purpose of this study was to examine the status of the terrestrial plant species available in Hamisi Sub County of Vihiga County. The study was based on the ecological period between 1985 and 2015. The mixed research method design was adopted and a sample size of 201 household heads was selected from a study population of 17095. The sub-county was stratified into two divisions purposively selected for the administration of questionnaires, then the target household heads population was selected through simple random sampling. Key informants such as KWS officers, local administrators, agricultural officers, environmental officers and CBO leaders were selected through purposive sampling. Primary data was obtained through direct field observation, photography, satellite images, questionnaire administration, interview of key informants and focus group discussion. Secondary data was obtained from documented material; textbooks, journals, magazines, published and unpublished government reports and websites. Data from questionnaires were analyzed descriptively (frequencies with their percentages, means and standard deviation) using SPSS and presented in form of tables, charts and graphs and discussion essays. The other quantitative data analysis was performed using ArcGIS Desktop tools and presented as satellite images, GIS plates and photographs. Qualitative data was analyzed from emerging themes. The study findings revealed that: The terrestrial plant species had declined to a large extent while others disappeared completely. This information was expected to be used by decision-makers to ensure a high percentage of terrestrial plant species diversity is restored for human well-being.&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/edu_01/0222/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Effects of Thermally-Oxidized Frying Oils (Corn Oil and Lard) on Gut Microbiota in Hamsters.

Repeated reuse of frying oil raises health concerns due to the accumulation of oxidative products after each frying cycle. Gut microbiota is integral in lipid metabolism and immune regulation. The present study was designed to investigate the effects of thermally-oxidized corn oil and lard on gut microbiota in relation to atherosclerosis, inflammatory cytokines, and plasma lipids. Male Golden Syrian hamsters were randomly divided into four groups and fed one of four diets containing fresh corn oil (CF), oxidized corn oil (CO), fresh lard (LF), and oxidized lard (LO), for six weeks. CO and LO were prepared by deep-frying potatoes in corn oil or lard for seven days. Results indicated that oxidized oil and lard caused the loss of species diversity and richness of gut microbiota. Feeding CO and LO also reduced the body and adipose tissue weights, associated with genus Acetatifactor and Allobaculum. Plasma triacylglycerols significantly increased by 51% in the CO and 35% in the LO group compared with that in their CF and LF counterparts, respectively. CO could also affect the abundance of specific bacteria genera: Bacteroides, Barnesiella, Acetatifactor, Allobaculum, Clostridium_IV, Clostridium_XIVa, Coprococcus, Lactococcus, Paraprevotella, Parasutterella, and Oscillibacter. In addition, CO and LO could adversely remodel gut composition and affect intestinal production of short-chain fatty acids, pro-inflammatory biomarkers (LPS and IL-6), anti-inflammatory biomarker IL-10, and atherosclerotic progression. It was concluded that frying oil could adversely modulate the gut microbiota and exacerbate the atherosclerosis at least in a hypercholesterolemia hamster model.

The evolutionary network of whiptail lizards reveals predictable outcomes of hybridization.

Hybridization between diverging lineages is associated with the generation and loss of species diversity, introgression, adaptation, and changes in reproductive mode, but it is unknown when and why it results in these divergent outcomes. We estimate a comprehensive evolutionary network for the largest group of unisexual vertebrates and use it to understand the evolutionary outcomes of hybridization. Our results show that rates of introgression between species decrease with time since divergence and suggest that species must attain a threshold of evolutionary divergence before hybridization results in transitions to unisexuality. Rates of hybridization also predict genome-wide patterns of genetic diversity in whiptail lizards. These results distinguish among models for hybridization that have not previously been tested and suggest that the evolutionary outcomes can be predictable.