Biologia最新文献

Plastic pollution in the environment becomes rapidly colonised by microbial communities, which often contain human bacterial pathogens. However, there is a lack of information about the interaction of fungal pathogens with plastic debris, particularly in marine environments. This study screened common plastic wastes collected from a range of recreational public and tourist beaches in Nigeria and Tanzania for colonisation by human pathogenic yeasts. Isolates were identified on selective media with confirmation by ITS sequencing. All beaches and all plastic polymer types were colonised by at least one species of human pathogenic yeast, with Candida tropicalis being the most frequently isolated species across both countries. Importantly, most of these pathogenic yeast isolates showed some level of resistance to fluconazole, which in Africa is the most commonly prescribed anti-fungal drug. Therefore, due to the high potential for human skin exposure at beach environments, plastic debris could pose a significant public health risk.

The genus Trichoderma is used worldwide to control fungal diseases and promote the growth of plants. It is the subject of many studies and forms part of most commercial formulations with biological control agents. In Brazil, it is used in approximately 78 registered commercial products. This work aims to isolate and evaluate the in vitro antagonism of Trichoderma endophytes from sugarcane, through pairing cultures and bioassays of the production of volatile and non-volatile metabolites, in addition to carrying out its molecular identification based on partial sequencing of molecular markers. In the paired culture assay against Fusarium verticillioides, Phaeocytostroma sacchari, Thielaviopsis sp. and Colletotrichum falcatum, mycelial growth inhibition rates were above 76.27%. In tests evaluating the production of volatile and non-volatile metabolites, the isolates promoted inhibitions that varied between 0 and 50.19% and 0 and 35.69%, respectively. According to the molecular phylogeny carried out, the concatenated analysis of the genetic markers revealed that the seven isolates belong to the species Trichoderma afroharzianum and, given the great potential as antagonists observed for sugarcane pathogens, they will be evaluated through in vivo disease control trials and tested for the growth promotion of this plant.

Fungal phytopathogens cause severe losses to crops worldwide and significantly reduce the quality and quantity of the produce. A shift towards reducing the usage of chemically synthesized pesticides by various biocontrol methods, strategies and approaches is observed in plant disease management. Symbiotic bacteria that live within the plant i.e. endophytes provide the host plant with many advantages in terms of metabolism and disease resistance. Bacterial antagonists play a significant role in controlling plant pathogens and diseases. In the present study 18 endophytic bacteria isolated from grape leaf were collected from ICAR-NRCG, Pune. In prospect to disease management, various endophytic bacteria were investigated for their antifungal activity against Sclerotium rolfsii, Macrophomina phaseolina, Alternaria spp., Fusarium spp. and Pythium spp. Dual culture antifungal activity indicated that 15 isolates have inhibitory effect against at least one of the tested pathogen. It was also observed that all the isolates have produced significant amount of hydrolytic enzymes i.e. cellulase, chitinase, amylase, protease and lipase, but the first two were the principal enzymes produced by them. These results provide a better understanding of endophytic bacteria in the control of pathogenic fungi and suggest their key role in the domain of biocontrol against diverse plant pathogens.

Artemisia L. is interesting in cytogenetic research due to having a variety of chromosome numbers and ploidy levels. In this research, the karyomorphological characteristics of nine accessions of French and Russian tarragon (A. dracunculus L.) collected from different locations in Iran were analyzed for the first time. The basic chromosome number was x = 9, with two ploidy levels of 4x (French accessions) and 10x (Russian accessions). The mean of chromosome length and the total haploid chromosome length of the French accessions ranged from 2.32 to 3.39 μm and 40.26 to 61.13 μm, respectively, while these values were 3.99 to 4.22 μm and 179.72 to 190.13 μm, respectively, for the Russian accessions. Chromosome types of French tarragons were determined as metacentric (dominant) and submetacentric, whereas they were metacentric (dominant), submetacentric, and subtelocentric in Russian tarragons. French accessions were classified as 4A, 3B, and 4B according to the Stebbins classification, while all the Russian accessions have a 3B type karyotype. Russian accessions present the most asymmetrical karyotype based on biplot analysis of asymmetry indices. Cluster analysis according to all karyotypic parameters revealed that the French and Russian accessions were placed in two separate groups. Principal components analysis showed that the first two components possessed 95.8% of the total variation. The PCA score plot generated from the first two principal components not only supported the clustering results but also distinguished the French accessions of Arak, Isfahan, and Tehran, which have more symmetrical karyotype, from the remaining French accessions.

The Caspian kutum, Rutilus frisii, is an anadromous fish native to Iran and despite the development of its hatchery production, its larval development has been poorly described; hence describing its morphological growth pattern was the aim of this study. The Caspian kutum larval period in the early development was divided into three stages, namely eleuthero-embryo (0–5 dph), propterygio-larvae (5–13 dph), pterygio-larvae (13–20 dph) and after larval period early juvenile was initiated (> 20 dph). The eleuthero-embryo stage was characterized by the commencement of mix-feeding while the yolk-sac remains, while propterygio-larvae absorbed the yolk-sac and continued to develop feeding apparatus and fin-folds. In pterygio-larvae, the fins developed and squamation began to appear. During the eleuthero-embryo stage, allometry in the head, trunk and tail were nearly isometric, negative, and positive, respectively. In propterygio-larvae, the head and tail allometry were positive, while the trunk was still negative. By the pterygio-larval stage, the tail and trunk allometry were nearly isometric but the head was positive. After metamorphosis, the growth pattern changed as the head and trunk allometry became nearly isometric and positive, respectively, but the tail allometry remained almost isometric. The results confirmed that morphological development and growth patterns during early life stages in R. frisii closely match its immediate required function.

Macroinvertebrates occupy an important trophic level in riverine ecosystems based on their composition and diversity. In this study, we explored the biodiversity pattern of macroinvertebrates in relation to environmental parameters in a bid to assess the water quality of the Uwagbe River, Nigeria. Sampling was carried out in three well marked stations from March 2018 to February 2020 following standard procedures. The physico-chemical parameters recorded were within the acceptable limit by World Health Organization and Federal Environmental Protection Agency of Nigeria standards except the pH and DO of Stations 2 and 3 and BOD of Station 3. The Principal Component Analysis showed pH and DO to be positively associated with Station 1. 13 orders of macroinvertebrates, comprising of 32 families, 45 taxa and 4,796 individuals were recorded. The most dominant order was Diptera (26.7%) while the least was Arachnida (0.1%). The most predominant taxon was Lumbricus sp. (7.9%), while the least was Aeschna sp. (4.3%). Diversity indices showed that Station 1 had the highest indices for Margalef index, Shannon-Wiener diversity index (H), Equitability index (E) and Simpsons’ dominance index while Station 3 had indices with the lowest values. Canonical Correspondence Analysis ordination showed that chloride, alkalinity, BOD, nitrate, phosphate and water depth were strongly correlated with families such as Lumbricidae, Chironomidae, Potamonautidae, Tabanidae and Palaemonidae in Station 3. DO and pH were strongly associated with Amphipodae, Hydrophilidae, Gerridae and Libellulidae families in Station 1. The study revealed the significance of the utility of macroinvertebrates community structure and its relationship with environmental factors in assessing the level of perturbation in riverine ecosystems. The results provide insight on how river managers can put in place appropriate conservation processes to forestall the incessant level of perturbation occurring in riverine ecosystems.

During a survey of plant-parasitic nematodes in South Africa's Limpopo Province, two species of Helicotylenchus were identified, namely H. dihystera and H. pseudorobustus. The morphological and molecular characteristics of these species were found to be consistent with those of the known species. A phylogenetic analysis of Helicotylenchus populations based on 28S rDNA was conducted, and it was found that the H. dihystera identified in this study belonged to the same group as other H. dihystera specimens with a 1.00 posterior probability support. Moreover, phylogenetic analysis of H. pseudorobustus based on 18S rDNA placed the test population close to other H. pseudorobustus specimens with 0.97 posterior probability. Scanning electron microscopy (SEM) for Helicotylenchus species also revealed noticeable dissimilarities in the labial disc and lateral field of the tail region between the two species from the present study, including H. pseudorobustus, and H. dihystera. The redundancy analysis (RDA) showed that H. pseudorobustus had a correlation with pH and clay of the soil. In conclusion, despite the challenges associated with identifying Helicotylenchus species, SEM and rDNA markers can be considered as highly effective tools to distinguish the species correctly and accurately.

The rise in industrial establishments all around the globe has also enhanced the demand of enzymes for usage in processes. Laccases are one of the dominant enzymes which have been employed in industrial processes over the years. They are a type of multi-copper oxidases (MCOs) which is a category of enzymes having diverse substrate selectivity and varying biological activity. All multi-copper oxidases can convert oxygen into water without creating unwanted products owing to the existence of cupredoxin-like domains. This review article details up-to-date knowledge about laccases, their structures and various sources, the laccase mediator system, mechanism of action and applications of laccases in numerous biotechnological processes such as in food industry for wine and beer stabilization, synthesis of cosmetics and pharmaceutically important compounds, dye detoxification in industrial effluents, xenobiotic degradation, paper and pulp bleaching, biofuel cells and biosensor development for detection for various chemical compounds.

Drought is an environmental stress factor restricting the growth and productivity of plants. Sugar beet can acclimate to diverse types of abiotic stress, such as drought. Although many studies on response of sugar beet to drought stress have been conducted, the expressions of drought-responsive genes in sugar beet have rarely been comprehensively investigated. In this study, we performed a transcriptome analysis of leaf samples from water-controlled sugar beet seedlings. The clean reads were obtained and assembled into 21,749 unique genes. Among them, we identified 1,675 differentially expressed genes (DEGs). According to the findings of the Gene ontology (GO) analysis, “biological process”, “metabolic process”, “oxidation–reduction process” and “catalytic activity” were the most highly enriched GO terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that “biosynthesis of secondary metabolites”, “metabolic pathways”, “plant hormone signal transduction”, and “protein processing in endoplasmic reticulum” were the four most highly enriched pathways. Drought stress significantly restrained dry mass and net photosynthetic rate of sugar beet. The expression levels of genes encoding homeobox-leucine zipper protein ATHB-12, berberine bridge enzyme-like 13, auxin response factor 5, and photosystem I subunit O were significantly altered under drought stress. In addition, 36 DEGs occurred with differential alternative splicing. Our findings provided new insights into the regulatory functions of genes related to drought resistance in sugar beet.

The study aimed to find the significant relations between the dominant plant species of secondary succession of lasting abandonment of agricultural fields on sandy soil in central Poland, and soil water repellency strength. The critical soil moisture content for hydrophobicity for individual sites ranged from 10.7 to 16.7%, and the differences were not statistically significant. After periods of prolonged drought, all abandonment agriculture fields indicated lower soil moisture content than critical threshold (10.7–16.7%) for soil water repellency. The soil water repellency was assessed as extreme class based on Water Drop Penetration Time (WDPT) test. The relationship between the main dominant species cover and WDPT test was diverse, with Agrostis gigantea agg. and Avena sativa as a species reaching highest cover within low values of WDPT. Inexpertly Betula pendula agg. (unexpectely) and Pinus sylvestris dominated sites with the highest values of WDPT test. The conducted research indicates that due to climate change, leaving sandy soils in warm temperate climate without an alternative management plan may pose a significant environmental risk.