RESUMEN

Currently, more and more lakes around the world are experiencing outbreaks of cyanobacterial blooms, and high-precision and rapid monitoring of the spatial distribution of algae in water bodies is an important task. Remote sensing technology is one of the effective means for monitoring algae in water bodies. Studies have shown that the Floating Algae Index (FAI) is superior to methods such as the Standardized Differential Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) in monitoring cyanobacterial blooms. However, compared to the NDVI method, the FAI method has difficulty in determining the threshold, and how to choose the threshold with the highest classification accuracy is challenging. In this study, FAI linear fitting model (FAI-L) is selected to solve the problem that FAI threshold is difficult to determine. Innovatively combine FAI index and NDVI index, and use NDVI index to find the threshold of FAI index. In order to analyze the applicability of FAI-L to extract cyanobacterial blooms, this paper selected multi-temporal Landsat8, HJ-1B, and Sentinel-2 remote sensing images as data sources, and took Chaohu Lake and Taihu Lake in China as research areas to extract cyanobacterial blooms. The results show that (1) the accuracy of extracting cyanobacterial bloom by FAI-L method is generally higher than that by NDVI and FAI. Under different data sources and different research areas, the average accuracy of extracting cyanobacterial blooms by FAI-L method is 95.13%, which is 6.98% and 18.43% higher than that by NDVI and FAI respectively. (2) The average accuracy of FAI-L method for extracting cyanobacterial blooms varies from 84.09 to 99.03%, with a standard deviation of 4.04, which is highly stable and applicable. (3) For simultaneous multi-source image data, the FAI-L method has the highest average accuracy in extracting cyanobacterial blooms, at 95.93%, which is 6.77% and 13.26% higher than NDVI and FAI methods, respectively. In this paper, it is found that FAI-L method shows high accuracy and stability in extracting cyanobacterial blooms, and it can extract the spatial distribution of cyanobacterial blooms well, which can provide a new method for monitoring cyanobacterial blooms.

Asunto(s)

RESUMEN

The accumulation of high amounts of plastic waste in the environment has raised ecological and health concerns, particularly in croplands, and biological degradation presents a promising approach for the sustainable treatment of this issue. In this study, a polyvinyl chloride (PVC)-degrading bacterium was isolated from farmland soil samples attached to waste plastic, utilizing PVC as the sole carbon source. The circular chromosome of the strain Cbmb3, with a length of 5,768,926 bp, was subsequently sequenced. The average GC content was determined to be 35.45%, and a total of 5835 open reading frames were identified. The strain Cbmb3 was designated as Bacillus toyonensis based on phylogenomic analyses and genomic characteristics. The bioinformatic analysis of the Cbmb3 genome revealed putative genes encoding essential enzymes involved in PVC degradation. Additionally, the potential genomic characteristics associated with phytoprobiotic effects, such as the synthesis of indole acetic acid and secondary metabolite synthesis, were also revealed. Overall, the present study provides the first complete genome of Bacillus toyonensis with PVC-degrading properties, suggesting that Cbmb3 is a potential strain for PVC bioremediation and application.

RESUMEN

Polyethylene (PE), a non-biodegradable plastic, is widely used in agriculture as a mulch material, which causes serious plastic pollution when it is discarded. Recent studies have described the biodeterioration of PE by bacteria, but it is difficult for a single bacterial species to effectively degrade PE plastic. We isolated two strains with PE-degrading ability, Bacillus cereus (E1) and Rhodococcus equi (E3), from the soil attached to plastic waste on the south side of Mount Tai, China, using a medium with PE plastic as the only carbon source. By clear zone area analysis, we found that E1 mixed with E3 could improve the degradation of PE plastics. The mixture of E1 and E3 was incubated for 110 days in a medium containing PE and mulch film as the only carbon source, respectively. After 110 days, a decrease in pH and mass was observed. Obvious slits and depressions were observed on the surface of the PE film and the mulch films using scanning electron microscopy. The surface hydrophobicity of both films decreased, and FTIR revealed the formation of new oxidation groups on their surfaces during the degradation process and the destruction of the original CH2 long chains of PE. Besides, we found that surface of the mulch films contained more viable bacteria than the liquid medium. In conclusion, we identified two PE-degrading strains whose mixture can effectively degrade mulch film than pure PE film. Our results provide a reference for understanding PE plastic degradation pathways and their associated degradation processes.

RESUMEN

The urban heat island effect caused by rapid urbanization has had a great impact on human health and ecological environment. The evolution of landscape patterns often affects regional thermal characteristics at the local scale. How to rationally allocate land cover types from the perspective of urban planning is a huge challenge. This paper takes Nanjing, a typical "stove city" in China, as an example to study the impact of landscape pattern changes on the urban thermal environment. Firstly, based on the "source" landscape "/sink" landscape identified by the "source-sink" landscape index, on this basis, the contributions of the "source-sink" landscape and its effects are calculated, and the temporal and spatial evolution laws are analyzed. Second, we study the cooling effect of different characteristic landscapes. The results show that the change of landscape pattern is closely related to the urban thermal environment, and the expansion of built-up areas is the main reason for the urban thermal environment. With the development of urbanization, the "source-sink" landscape structure in most districts and counties has aggravated the heat island effect, and the ratios of "sink" and "source" landscape contribution ratios with strong levels are concentrated in the suburban areas. The results of cooling efficiency research show that the cooling range of forest land is larger than that of water bodies. At the same time, we found that the cooling efficiency of the sink landscape is the highest when the area of the sink landscape is 0.18-0.9 hm2 and the shape index is between 1 and 4. The research results can provide feasible and practical scientific suggestions for the planning and ecological construction of Nanjing.

Asunto(s)

RESUMEN

Microplastics (MPs) and nanoplastic (NPs) pollution is a global concern due to the massive use of plastic products. Although there have been many studies on the treatments of animals with MPs/NPs, there are few systematic summaries of MPs/NPs translocation and hazards in animals. This review comprehensively summarizes the pathways by which animals are exposed to MPs/NPs in the environment, in particular, to summarize in detail their translocation and hazards in vivo. Studies have shown that MPs/NPs enter the animals' body through water, food, breath and even skin, enter the blood circulation through the lungs and digestive tract, and eventually accumulate in various tissues. After a summary of the studies, we found a high correlation between the tissue accumulation of MPs/NPs and their particle size, with 4-20 µm MPs appearing to be more prone to accumulate in tissues. These MPs/NPs accumulated in animal tissues may be transferred to humans through the food chain. Thus, we summarized the studies on the accumulation of MPs/NPs in livestock and poultry products, showing that MPs/NPs in livestock and poultry products gradually increased with the complexity of processing and packaging processes. There are few reports related to direct contamination of livestock products by MPs/NPs, we hope that this review will bring together the growing body of evidence that MPs/NPs can directly harm human health through the food chain.

Asunto(s)

RESUMEN

Chryseobacterium spp. are Gram-negative rods found ubiquitously in the environment, with certain species being reported as having unusual degrading properties. Polyvinyl alcohol (PVA) is used widely in industry but causes serious global environmental pollution. Here, we report the complete genome sequence of a novel bacterium, AC3, that efficiently degrades PVA. As the representative genome of Chryseobacterium nepalense, key genomic characteristics (e.g., mobile genetic elements, horizontal genes, genome-scale metabolic network, secondary metabolite biosynthesis gene clusters, and carbohydrate-active enzymes) were comprehensively investigated to reveal the potential genetic features of this species. Core genome phylogenetic analysis in combination with average nucleotide identity, average amino acid identity, and in silico DNA-DNA hybridization values provided an accurate taxonomic position of C. nepalense in the genus Chryseobacterium. Comparative genomic analysis of AC3 with closely related species suggested evolutionary dynamics characterized by a species-specific genetic repertoire, dramatic rearrangements, and evolutionary constraints driven by selective pressure, which facilitated the speciation and adaptative evolution of C. nepalense. Biogeographic characterization indicated that this species is ubiquitously distributed not only in soil habitats but also in a variety of other source niches. Bioinformatic analysis revealed the potential genetic basis of PVA degradation in AC3, which included six putative genes associated with the synthesis of PVA dehydrogenase, cytochrome c, oxidized PVA hydrolase, and secondary alcohol dehydrogenase. Our study reports the first complete genome of C. nepalense with PVA-degrading properties, providing comprehensive insights into the genomic characteristics of this species and increasing our understanding of the microbial degradation of PVA. IMPORTANCE Although PVA is a biodegradable polymer, the widespread use of PVA in global industrialization has resulted in serious environmental problems. To date, knowledge of effective and applicable PVA-degrading bacteria is limited, and thus, the discovery of novel PVA biodegraders is pertinent. Here, we isolated a novel bacterial strain, AC3, which efficiently degraded PVA. The complete genome of AC3 was sequenced as the first genome sequence of the species C. nepalense. Comparative genomic analysis was performed to comprehensively investigate the phylogenetic relationships, genome-scale metabolic network, key genomic characteristics associated with genomic evolution, evolutionary dynamics between AC3 and its close relatives, and biogeographic characterization of C. nepalense, particularly regarding the potential genetic basis of PVA degradation. These findings could advance our understanding of the genomic characteristics of C. nepalense and PVA bioremediation.

Asunto(s)

RESUMEN

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by more than sixty genes identified through classic linkage analysis and new sequencing methods. Yet no clear mechanism of onset, cure, or effective treatment is known. Popular discourse classifies the proteins encoded from ALS-related genes into four disrupted processes: proteostasis, mitochondrial function and ROS, nucleic acid regulation, and cytoskeletal dynamics. Surprisingly, the mechanisms detailing the contribution of the neuronal cytoskeletal in ALS are the least explored, despite involvement in these cell processes. Eight genes directly regulate properties of cytoskeleton function and are essential for the health and survival of motor neurons, including: TUBA4A, SPAST, KIF5A, DCTN1, NF, PRPH, ALS2, and PFN1. Here we review the properties and studies exploring the contribution of each of these genes to ALS.

Asunto(s)

RESUMEN

Profilin-1 (PFN1) is a cytoskeletal protein that regulates the dynamics of actin and microtubule assembly. Thus, PFN1 is essential for the normal division, motility, and morphology of cells. Unfortunately, conventional fusion and direct labeling strategies compromise different facets of PFN1 function. As a consequence, the only methods used to determine known PFN1 functions have been indirect and often deduced in cell-free biochemical assays. We engineered and characterized two genetically encoded versions of tagged PFN1 that behave identical to each other and the tag-free protein. In biochemical assays purified proteins bind to phosphoinositide lipids, catalyze nucleotide exchange on actin monomers, stimulate formin-mediated actin filament assembly, and bound tubulin dimers (kD = 1.89 µM) to impact microtubule dynamics. In PFN1-deficient mammalian cells, Halo-PFN1 or mApple-PFN1 (mAp-PEN1) restored morphological and cytoskeletal functions. Titrations of self-labeling Halo-ligands were used to visualize molecules of PFN1. This approach combined with specific function-disrupting point-mutants (Y6D and R88E) revealed PFN1 bound to microtubules in live cells. Cells expressing the ALS-associated G118V disease variant did not associate with actin filaments or microtubules. Thus, these tagged PFN1s are reliable tools for studying the dynamic interactions of PFN1 with actin or microtubules in vitro as well as in important cell processes or disease-states.

Asunto(s)

RESUMEN

Renal ischemia-reperfusion injury (IRI) is histologically characterized by tubular cell death. Diverse pathways of regulated cell death (RCD) have been reported to contribute to renal IRI in recent studies. In this review, we discuss the signaling pathways, regulators and crosstalk of RCD, including necroptosis, ferroptosis and pyroptosis, and their role in renal IRI in order to pave the way for new therapeutic opportunities.

Asunto(s)

RESUMEN

The pollution of plastic waste has become an increasingly serious environmental crisis. Recently, plastic has been detected in various kinds of environments, even in human tissues, which is an increasing threat to the ecosystems and humans. In the ocean, the plastic waste is eventually fragmentized into microplastics (MPs) under the disruption of physical and chemical processes. MPs are colonized by microbial communities such as fungi, diatoms, and bacteria, which form biofilms on the surface of the plastic called "plastisphere". In this review, we summarize the studies related to microorganisms in the plastisphere in recent years and describe the microbial species in the plastisphere, mainly including bacteria, fungi, and autotrophs. Secondly, we explore the interactions between MPs and the plastisphere. The depth of MPs in the ocean and the nutrients in the surrounding seawater can have a great impact on the community structure of microorganisms in the plastisphere. Finally, we discuss the types of MP-degrading bacteria in the ocean, and use the "seed bank" theory to speculate on the potential sources of MP-degrading microorganisms. Challenges and future research prospects are also discussed.

RESUMEN

Eight separate mutations in the actin-binding protein profilin-1 have been identified as a rare cause of amyotrophic lateral sclerosis (ALS). Profilin is essential for many neuronal cell processes through its regulation of lipids, nuclear signals, and cytoskeletal dynamics, including actin filament assembly. Direct interactions between profilin and actin monomers inhibit actin filament polymerization. In contrast, profilin can also stimulate polymerization by simultaneously binding actin monomers and proline-rich tracts found in other proteins. Whether the ALS-associated mutations in profilin compromise these actin assembly functions is unclear. We performed a quantitative biochemical comparison of the direct and formin mediated impact for the eight ALS-associated profilin variants on actin assembly using classic protein-binding and single-filament microscopy assays. We determined that the binding constant of each profilin for actin monomers generally correlates with the actin nucleation strength associated with each ALS-related profilin. In the presence of formin, the A20T, R136W, Q139L, and C71G variants failed to activate the elongation phase of actin assembly. This diverse range of formin-activities is not fully explained through profilin-poly-L-proline (PLP) interactions, as all ALS-associated variants bind a formin-derived PLP peptide with similar affinities. However, chemical denaturation experiments suggest that the folding stability of these profilins impact some of these effects on actin assembly. Thus, changes in profilin protein stability and alterations in actin filament polymerization may both contribute to the profilin-mediated actin disruptions in ALS.

Asunto(s)

RESUMEN

Delftia tsuruhatensis strains have long been known to promote plant growth and biological control. Recently, it has become an emerging opportunistic pathogen in humans. However, the genomic characteristics of the genetic diversity, pathogenicity, and biotechnological properties have not yet been comprehensively investigated. Here, a comparative pan-genome analysis was constructed. The open pan-genome with a large and flexible gene repertoire exhibited a high degree of genetic diversity. The purifying selection was the main force to drive pan-genome evolution. Significant differences were observed in the evolutionary relationship, functional enrichment, and degree of selective pressure between the different components of the pan-genome. A high degree of genetic plasticity was characterized by the determinations of diverse mobile genetic elements (MGEs), massive genomic rearrangement, and horizontal genes. Horizontal gene transfer (HGT) plays an important role in the genetic diversity of this bacterium and the formation of genomic traits. Our results revealed the occurrence of diverse virulence-related elements associated with macromolecular secretion systems, virulence factors associated with multiple nosocomial infections, and antimicrobial resistance, indicating the pathogenic potential. Lateral flagellum, T1SS, T2SS, T6SS, Tad pilus, type IV pilus, and a part of virulence-related genes exhibited general properties, whereas polar flagellum, T4SS, a part of virulence-related genes, and resistance genes presented heterogeneous properties. The pan-genome also harbors abundant genetic traits related to secondary metabolism, carbohydrate active enzymes (CAZymes), and phosphate transporter, indicating rhizosphere adaptation, plant growth promotion, and great potential uses in agriculture and biological control. This study provides comprehensive insights into this uncommon species from the genomic perspective. IMPORTANCE D. tsuruhatensis is considered a plant growth-promoting rhizobacterium (PGPR), an organic pollutant degradation strain, and an emerging opportunistic pathogen to the human. However, the genetic diversity, the evolutionary dynamics, and the genetic basis of these remarkable traits are still little known. We constructed a pan-genome analysis for D. tsuruhatensis and revealed extensive genetic diversity and genetic plasticity exhibited by open pan-genome, diverse mobile genetic elements (MGEs), genomic rearrangement, and horizontal genes. Our results highlight that horizontal gene transfer (HGT) and purifying selection are important forces in D. tsuruhatensis genetic evolution. The abundant virulence-related elements associated with macromolecular secretion systems, virulence factors, and antimicrobial resistance could contribute to the pathogenicity of this bacterium. Therefore, clinical microbiologists need to be aware of D. tsuruhatensis as an opportunistic pathogen. The genetic profiles of secondary metabolism, carbohydrate active enzymes (CAZymes), and phosphate transporter could provide insight into the genetic armory of potential applications for agriculture and biological control of D. tsuruhatensis in general.

Asunto(s)