Phytoestrogen signaling and symbiotic gene activation are disrupted by endocrine-disrupting chemicals

A Review of Bioactive Compound Effects from Primary Legume Protein Sources in Human and Animal Health

The global demand for sustainable and nutritious food sources has catalyzed interest in legumes, known for their rich repertoire of health-promoting compounds. This review delves into the diverse array of bioactive peptides, protein subunits, isoflavones, antinutritional factors, and saponins found in the primary legume protein sources-soybeans, peas, chickpeas, and mung beans. The current state of research on these compounds is critically evaluated, with an emphasis on the potential health benefits, ranging from antioxidant and anticancer properties to the management of chronic diseases such as diabetes and hypertension. The extensively studied soybean is highlighted and the relatively unexplored potential of other legumes is also included, pointing to a significant, underutilized resource for developing health-enhancing foods. The review advocates for future interdisciplinary research to further unravel the mechanisms of action of these bioactive compounds and to explore their synergistic effects. The ultimate goal is to leverage the full spectrum of benefits offered by legumes, not only to advance human health but also to contribute to the sustainability of food systems. By providing a comprehensive overview of the nutraceutical potential of legumes, this manuscript sets a foundation for future investigations aimed at optimizing the use of legumes in the global pursuit of health and nutritional security.

Ecotoxicological implications of residual pesticides to beneficial soil bacteria: A review

Optimization of crop production in recent times has become essential to fulfil food demands of constantly increasing human populations worldwide. To address this formidable challenge, application of agro-chemicals including synthetic pesticides in intensive farm practices has increased alarmingly. The excessive and indiscriminate application of pesticides to foster food production however, leads to its exorbitant deposition in soils. After accumulation in soils beyond threshold limits, pesticides harmfully affect the abundance, diversity and composition and functions of rhizosphere microbiome. Also, the cost of pesticides and emergence of resistance among insect-pests against pesticides are other reasons that require attention. Due to this, loss in soil nutrient pool cause a substantive reduction in agricultural production which warrant the search for newer environmentally friendly technology for sustainable crop production. Rhizosphere microbes, in this context, play vital roles in detoxifying the polluted environment making soil amenable for cultivation through detoxification of pollutants, rhizoremediation, bioremediation, pesticide degradation, and stress alleviation, leading to yield optimization. The response of soil microorganisms to range of chemical pesticides is variable ranging from unfavourable to the death of beneficial microbes. At cellular and biochemical levels, pesticides destruct the morphology, ultrastructure, viability/cellular permeability, and many biochemical reactions including protein profiles of soil bacteria. Several classes of pesticides also disturb the molecular interaction between crops and their symbionts impeding the overall useful biological processes. The harmful impact of pesticides on soil microbes, however, is poorly researched. In this review, the recent findings related with potential effects of synthetic pesticides on a range of soil microbiota is highlighted. Emphasis is given to find and suggest strategies to minimize the chemical pesticides usage in the real field conditions to preserve the viability of soil beneficial bacteria and soil quality for safe and sustainable crop production even in pesticide contaminated soils.

Phoma medicaginis Isolate Differences Determine Disease Severity and Phytoestrogen Production in Annual Medicago spp

Phoma black stem and leaf spot disease of annual Medicago spp., caused by Phoma medicaginis, not only can devastate forage and seed yield but can reduce herbage quality by inducing production of phytoestrogens (particularly coumestrol and 4'-O-methylcoumestrol), which can also reduce the ovulation rates of animals grazing infected forage. We determined the consequent phytoestrogen levels on three different annual Medicago species/cultivars (Medicago truncatula cultivar Cyprus, Medicago polymorpha var. brevispina cultivar Serena, and Medicago murex cultivar Zodiac) after inoculation with 35 isolates of P. medicaginis. Across the isolate × cultivar combinations, leaf disease incidence, petiole/stem disease incidence, leaf disease severity, petiole disease severity, and leaf yellowing severity ranged up to 100, 89.4, 100, 58.1, and 61.2%, respectively. Cultivars Cyprus and Serena were the most susceptible and cultivar Zodiac was the most resistant to P. medicaginis. Isolates WAC3653, WAC3658, and WAC4252 produced the most severe disease. Levels of phytoestrogens in stems ranged from 25 to 1,995 mg/kg for coumestrol and from 0 to 418 mg/kg for 4'-O-methylcoumestrol. There was a significant positive relationship of disease incidence and severity parameters with both coumestrol and 4'-O-methylcoumestrol contents, as noted across individual cultivars and across the three cultivars overall, where r = 0.39 and 0.37 for coumestrol and 4'-O-methylcoumestrol, respectively (P < 0.05). Although cultivar Serena was most susceptible to P. medicaginis and produced the highest levels of phytoestrogens in the presence of P. medicaginis, cultivar Zodiac contained the highest levels of phytoestrogens in comparison with other cultivars in the absence of P. medicaginis. There was a 15-fold increase in coumestrol in cultivar Serena but only a 7-fold increase in cultivar Zodiac from infection of P. medicaginis. The study highlights that the intrinsic ability of a particular cultivar to produce phytoestrogens in the absence of the pathogen, and its comparative ability to produce phytoestrogens in the presence of the P. medicaginis, are both important and highly relevant to developing new annual Medicago spp. cultivars that offer improved disease resistance and better animal reproductive outcomes.

Estrogenic response in Japanese turtle (Mauremys japonica) exposed to petroleum hydrocarbon

Expressions of the estrogen receptors and vitellogenin in Japanese turtle (Mauremys japonica) in response to petroleum hydrocarbon were studied. A total of 15 male turtles were exposed to 1.00 mg L^-1 of a sample of an oil spill, and 15 male and 15 female turtles were served as controls without an oil spill. The transcripts' results demonstrated an increase over time with greater expression of vitellogenin I in males exposed to petroleum with significant differences. In the case of vitellogenin II, the expression was greater than control males, but it was similar to the values of control females. Concerning the estrogen receptor and estrogen receptor , males exposed to oil spill presented higher values at 72 hr than the controls. In conclusion, in the present work, the effect of petroleum as an endocrine disruptor in turtles was demonstrated, and it can be used to identify damages induced by the presence of hydrocarbons in aquatic environments.

Hormonally active phytochemicals from macroalgae: A largely untapped source of ligands to deorphanize nuclear receptors in emerging marine animal models

Hormonally active phytochemicals (HAPs) are signaling molecules produced by plants that alter hormonal signaling in animals, due to consumption or environmental exposure. To date, HAPs have been investigated mainly in terrestrial ecosystems. To gain a full understanding of the origin and evolution of plant-animal interactions, it is necessary also to study these interactions in the marine environment, where the major photosynthetic lineages are very distant from the terrestrial plants. Here we focus on chemicals from red and brown macroalgae and point out their potential role as modulators of the endocrine system of aquatic animals through nuclear hormone receptors. We show that, regarding steroids and oxylipins, there are already some candidates available for further functional investigations of ligand-receptor interactions. Furthermore, several carotenoids, produced by cyanobacteria provide candidates that could be investigated with respect to their presence in macroalgae. Finally, regarding halogenated compounds, it is not clear yet which molecules could bridge the gap to explain the transition from lipid sensing to thyroid hormone high affinity binding among nuclear receptors.

Disturbing Effects of Chronic Low-dose 4-Nonylphenol exposing on Gonadal Weight and Reproductive Outcome over One-generation

4-Nonylphenol (NP) is a surfactant that is a well-known and widespread estrogenic endocrine disrupting chemical (EDC). Although it has been known that the affinity of NP to ERs is low, it has been suggested that low-dose NP has toxicity. In the present study, the endocrine disrupting effects on reproduction, and the weight of gonads, epididymis, and uterus were evaluated with the chronic lower-dose NP exposing. This study was designed by following the OECD test guideline 443 and subjected to a complete necropsy. In male, NP had an effect on the weight of the testis and epididymis in both F₀ and F₁. In females, NP decreased the weight of ovary and uterus in F₀ but not in pre-pubertal F₁ pubs. Fertility of male and female in F₀ or F₁ was no related with NP administration. The number of caudal-epididymal sperm by body weight (BW) was not different between groups in both F₀ and F₁. Besides, the difference of the sperm number between generations was not detected. The number of ovulated oocytes was similar between groups in F₀, but significantly decreased in NP 50 group of F₁. The litter size and sex ratios of offspring in F₁ and F₂ were not different. The accumulated mating rate and gestation period were not affected by the NP administration. Those results shows that chronic lower-dose NP administration has an effect of endocrine disruptor on the weight of gonads and epididymis of F₀ and F₁ but not in reproduction. Based on the results, it is suggested that chronic lower-dose NP exposing causes endocrine disruption in the weight of gonad and epididymis but not in the reproductive ability of next generations.

Legume-rhizobia signal exchange: promiscuity and environmental effects

Although signal exchange between legumes and their rhizobia is among the best-known examples of this biological process, most of the more characterized data comes from just a few legume species and environmental stresses. Although a relative wealth of information is available for some model legumes and some of the major pulses such as soybean, little is known about tropical legumes. This relative disparity in current knowledge is also apparent in the research on the effects of environmental stress on signal exchange; cool-climate stresses, such as low-soil temperature, comprise a relatively large body of research, whereas high-temperature stresses and drought are not nearly as well understood. Both tropical legumes and their environmental stress-induced effects are increasingly important due to global population growth (the demand for protein), climate change (increasing temperatures and more extreme climate behavior), and urbanization (and thus heavy metals). This knowledge gap for both legumes and their environmental stresses is compounded because whereas most temperate legume-rhizobia symbioses are relatively specific and cultivated under relatively stable environments, the converse is true for tropical legumes, which tend to be promiscuous, and grow in highly variable conditions. This review will clarify some of this missing information and highlight fields in which further research would benefit our current knowledge.

Polyphenols and the human brain: plant “secondary metabolite” ecologic roles and endogenous signaling functions drive benefits

Flavonoids and other polyphenols are ubiquitous plant chemicals that fulfill a range of ecologic roles for their home plant, including protection from a range of biotic and abiotic stressors and a pivotal role in the management of pathogenic and symbiotic soil bacteria and fungi. They form a natural part of the human diet, and evidence suggests that their consumption is associated with the beneficial modulation of a number of health-related variables, including those related to cardiovascular and brain function. Over recent years, the consensus as to the mechanisms responsible for these effects in humans has shifted away from polyphenols having direct antioxidant effects and toward their modulation of cellular signal transduction pathways. To date, little consideration has been given to the question of why, rather than how, these plant-derived chemicals might exert these effects. Therefore, this review summarizes the evidence suggesting that polyphenols beneficially affect human brain function and describes the current mechanistic hypotheses explaining these effects. It then goes on to describe the ecologic roles and potential endogenous signaling functions that these ubiquitous phytochemicals play within their home plant and discusses whether these functions drive their beneficial effects in humans via a process of “cross-kingdom” signaling predicated on the many conserved similarities in plant, microbial, and human cellular signal transduction pathways.

Estrogenic effect of the phytoestrogen biochanin A in zebrafish, Danio rerio, and brown trout, Salmo trutta

Isoflavones with estrogenic activity produced in Fabaceae plants are known to leach from agricultural areas to freshwater systems, but the effect of waterborne isoflavones in fish has not been thoroughly characterized. Therefore, the estrogenic effect of waterborne biochanin A was investigated in zebrafish (Danio rerio) and juvenile brown trout (Salmo trutta). Exposure of juvenile brown trout to 10 μg biochanin AL(-1) or higher caused marked vitellogenin induction after 9-10 days of exposure and so did exposure to 186 μg biochanin AL(-1) for 6h. Following 8d of exposure, a NOEC for induction of vitellogenin production in male zebrafish was 70 and LOEC 114 μg biochanin AL(-1). Exposure to 209 μg biochanin AL(-1) from hatch to 60 days post hatch (dph) caused a skewing of the sex ratio toward more phenotypic female zebrafish, but did not cause induction of vitellogenin in male and undifferentiated fish.

IN CONCLUSION

(1) biochanin A elicits estrogenic effects in trout at environmentally realistic concentrations, (2) brown trout plasma vitellogenin concentrations respond to lower biochanin A exposure concentrations than vitellogenin concentrations in zebrafish homogenates and (3) concerning vitellogenin induction, the hypothesis should be tested if short term tests with zebrafish may show a higher sensitivity than partial life cycle tests.

Impacts of organic and conventional crop management on diversity and activity of free-living nitrogen fixing bacteria and total bacteria are subsidiary to temporal effects

A three year field study (2007–2009) of the diversity and numbers of the total and metabolically active free-living diazotophic bacteria and total bacterial communities in organic and conventionally managed agricultural soil was conducted using the Nafferton Factorial Systems Comparison (NFSC) study, in northeast England. Fertility management appeared to have little impact on both diazotrophic and total bacterial communities. However, copy numbers of the nifH gene did appear to be negatively impacted by conventional crop protection measures across all years suggesting diazotrophs may be particularly sensitive to pesticides. Impacts of crop management were greatly overshadowed by the influence of temporal effects with diazotrophic communities changing on a year by year basis and from season to season. Quantitative analyses using qPCR of each community indicated that metabolically active diazotrophs were highest in year 1 but the population significantly declined in year 2 before recovering somewhat in the final year. The total bacterial population in contrast increased significantly each year. It appeared that the dominant drivers of qualitative and quantitative changes in both communities were annual and seasonal effects. Moreover, regression analyses showed activity of both communities was significantly affected by soil temperature and climatic conditions.

Lumiestrone is Photochemically Derived from Estrone and may be Released to the Environment without Detection

Endocrine disrupting chemicals are adversely affecting the reproductive health and metabolic status of aquatic vertebrates. Estrone is often the dominant natural estrogen in urban sewage, yet little is known about its environmental fate and biological effects. Increased use of UV-B radiation for effluent treatments, and exposure of effluents to sunlight in holding ponds led us to examine the effects of environmentally relevant levels of UV-B radiation on the photodegradation potential of estrone. Surprisingly, UV-B-mediated degradation leads to the photoproduction of lumiestrone, a little known 13α-epimer form of estrone. We show for the first time that lumiestrone possesses novel biological activity. In vivo treatment with estrone stimulated estrogen receptor (ER) α mRNA production in the male goldfish liver, whereas lumiestrone was without effect, suggesting a total loss of estrogenicity. In contrast, results from in vitro ER-dependent reporter gene assays indicate that lumiestrone showed relatively higher estrogenic potency with the zebrafish ERβ2 than zfERα, suggesting that it may act through an ERβ-selectivity. Lumiestrone also activated human ERs. Microarray analysis of male goldfish liver following in vivo treatments showed that lumiestrone respectively up- and down-regulated 20 and 69 mRNAs, which was indicative of metabolic upsets and endocrine activities. As a photodegradation product from a common estrogen of both human and farm animal origin, lumiestrone is present in sewage effluent, is produced from estrone upon exposure to natural sunlight and should be considered as a new environmental contaminant.

Pesticides reduce symbiotic efficiency of nitrogen-fixing rhizobia and host plants

Unprecedented agricultural intensification and increased crop yield will be necessary to feed the burgeoning world population, whose global food demand is projected to double in the next 50 years. Although grain production has doubled in the past four decades, largely because of the widespread use of synthetic nitrogenous fertilizers, pesticides, and irrigation promoted by the "Green Revolution," this rate of increased agricultural output is unsustainable because of declining crop yields and environmental impacts of modern agricultural practices. The last 20 years have seen diminishing returns in crop yield in response to increased application of fertilizers, which cannot be completely explained by current ecological models. A common strategy to reduce dependence on nitrogenous fertilizers is the production of leguminous crops, which fix atmospheric nitrogen via symbiosis with nitrogen-fixing rhizobia bacteria, in rotation with nonleguminous crops. Here we show previously undescribed in vivo evidence that a subset of organochlorine pesticides, agrichemicals, and environmental contaminants induces a symbiotic phenotype of inhibited or delayed recruitment of rhizobia bacteria to host plant roots, fewer root nodules produced, lower rates of nitrogenase activity, and a reduction in overall plant yield at time of harvest. The environmental consequences of synthetic chemicals compromising symbiotic nitrogen fixation are increased dependence on synthetic nitrogenous fertilizer, reduced soil fertility, and unsustainable long-term crop yields.

Diverse flavonoids stimulate NodD1 binding to nod gene promoters in Sinorhizobium meliloti

NodD1 is a member of the NodD family of LysR-type transcriptional regulators that mediates the expression of nodulation (nod) genes in the soil bacterium Sinorhizobium meliloti. Each species of rhizobia establishes a symbiosis with a limited set of leguminous plants. This host specificity results in part from a NodD-dependent upregulation of nod genes in response to a cocktail of flavonoids in the host plant's root exudates. To demonstrate that NodD is a key determinant of host specificity, we expressed nodD genes from different species of rhizobia in a strain of S. meliloti lacking endogenous NodD activity. We observed that nod gene expression was initiated in response to distinct sets of flavonoid inducers depending on the source of NodD. To better understand the effects of flavonoids on NodD, we assayed the DNA binding activity of S. meliloti NodD1 treated with the flavonoid inducer luteolin. In the presence of luteolin, NodD1 exhibited increased binding to nod gene promoters compared to binding in the absence of luteolin. Surprisingly, although they do not stimulate nod gene expression in S. meliloti, the flavonoids naringenin, eriodictyol, and daidzein also stimulated an increase in the DNA binding affinity of NodD1 to nod gene promoters. In vivo competition assays demonstrate that noninducing flavonoids act as competitive inhibitors of luteolin, suggesting that both inducing and noninducing flavonoids are able to directly bind to NodD1 and mediate conformational changes at nod gene promoters but that only luteolin is capable of promoting the downstream changes necessary for nod gene induction.

Convergence of hormones and autoinducers at the host/pathogen interface

Most living organisms possess sophisticated cell-signaling networks in which lipid-based signals modulate biological effects such as cell differentiation, reproduction and immune responses. Acyl homoserine lactone (AHL) autoinducers are fatty acid-based signaling molecules synthesized by several Gram-negative bacteria that are used to coordinate gene expression in a process termed "quorum sensing" (QS). Recent evidence shows that autoinducers not only control gene expression in bacterial cells, but also alter gene expression in mammalian cells. These alterations include modulation of proinflammatory cytokines and induction of apoptosis. Some of these responses may have deleterious effects on the host's immune response, thereby leading to increased bacterial pathogenesis. Prokaryotes and eukaryotes have cohabited for approximately two billion years, during which time they have been exposed to each others' soluble signaling molecules. We postulate that organisms from the different kingdoms of nature have acquired mechanisms to sense and respond to each others signaling molecules, and we have named this process interkingdom signaling. We further propose that autoinducers, which exhibit structural and functional similarities to mammalian lipid-based hormones, are excellent candidates for mediating this interkingdom communication. Here we will compare and contrast bacterial QS systems with eukaryotic endocrine systems, and discuss the mechanisms by which autoinducers may exploit mammalian signal transduction pathways.

Epigenetics, evolution, endocrine disruption, health, and disease

Endocrine-disrupting chemicals (EDCs) in the environment have been linked to human health and disease. This is particularly evident in compounds that mimic the effects of estrogens. Exposure to EDCs early in life can increase risk levels of compromised physical and mental health. Epigenetic mechanisms have been implicated in this process. Transgenerational consequences of EDC exposure is also discussed in both a proximate (mechanism) and ultimate (evolution) context as well as recent work suggesting how such transmission might become incorporated into the genome and subject to selection. We suggest a perspective for exploring and ultimately coming to understand diseases that may have environmental or endocrine origins.

Endocrine disrupters: a human risk?

Endocrine disrupters (EDs) alter normal hormonal regulation and may be naturally occurring or environmental contaminants. Classically, EDs act genomically, with agonistic or antagonistic effects on steroid receptors and may alter reproductive function and/or cause feminisation by binding to oestrogen or androgen receptors; their binding to the thyroid receptor may dysregulate the neuroendocrine system. Recently, it has been shown that EDs can also act by non-genomic mechanisms, altering steroid synthesis (inhibition of cytochrome P450 isoforms) or steroid metabolism. The alkylphenol and phthalate plasticisers inhibit the inactivation of oestrogens by sulphation (via SULT 1A1 and 1E1 isoforms) and so cause a rise in levels of the free active endogenous oestrogens. A range of ED effects have been shown in mammals, fish, birds, reptiles, amphibia and aquatic invertebrates but it is not yet clear whether these processes also occur in human beings. It is evident that EDs, as well as altering reproduction, can cause changes in neurosteroid levels and so have the potential to affect immune function, behaviour and memory. This may be of long-term concern since traces of EDs such as plasticisers, brominated fire retardants, sunscreen agents and cosmetic ingredients are widely distributed in the environment and in human biofluids.

Occurrence and fate of pharmaceuticals and personal care products (PPCPs) in biosolids

Each year, large quantities of pharmaceuticals and personal care products (PPCPs) are used worldwide. Once conveyed to wastewater treatment plants, PPCPs can remain unchanged or undergo partial or complete transformation during wastewater treatment processes before discharge into the environment via effluent and biosolids for land application. Biosolids can be a major sink for some PPCPs. Previous investigations have indicated that land application of biosolids may be a potential important route through which PPCPs enter the environment. However, no information is available on exactly how closely the concentrations of PPCPs in the environmental media are related to the land application of PPCP-containing biosolids. This paper reviews currently available information on the occurrence of PPCPs in biosolids, methods of analysis, the potential fate of PPCPs in biosolids-applied soils, and composting as a potential means for removal of PPCPs from biosolids.