The impact of polystyrene nanoplastics (PSNPs) on physiological and biochemical parameters of the microalgae Spirulina platensis.

Nanoplastics, as emerging pollutants, have harmful effects on living organisms and the environment, the mechanisms and extent of which remain unclear. Microalgae, as one of the most important biological groups in the food chain and sensitive environmental indicators to various pollutants, are considered a suitable option for investigating the effects of nanoplastics. In this study, the effects of polystyrene nanoplastics on the growth rate, dry weight, chlorophyll a and carotenoid levels, proline, and lipid peroxidation in the Spirulina platensis were examined. Three concentrations of 0.1, 1, and 10 mg L-1 of PSNPs were used alongside a control sample with zero concentration, with four repetitions in one-liter containers for 20 days under optimal temperature and light conditions. Various analyses, including growth rate, dry weight, proline, chlorophyll a and carotenoid levels, and lipid peroxidation, were performed. The results indicated that exposure to PSNP stress led to a significant decrease in growth rate, dry weight, and chlorophyll a and carotenoid levels compared to the control sample. Furthermore, this stress increased the levels of proline and lipid peroxidation in Spirulina platensis. Morphological analysis via microscopy supported these findings, indicating considerable environmental risks associated with PSNPs.

Green Synthesis of Silver Nanoparticles by Fusarium oxysporum and its Function Against Aspergillus and Fusarium Fungi.

(NPs) can be produced by various methods such as physical and chemical processes. However, environmentally friendly ways are increasingly requested. In this research, (Ag-NPs) were produced by Fusarium oxysporum, and its antifungal effect on Aspergillus and Fusarium was investigated. Nanoparticles were produced by silver nitrate salt and Fusarium oxysporum native to Isfahan city. In order to optimize the synthesis conditions, optimization of some factors such as volume, concentration, time, temperature, and pH of the extract was performed. The structural and physical properties of NPs were determined by spectrophotometer, XRD, FTIR FESEM, SEM, and TEM microscopy. For the study of the inhibitory effect of NPs on Fusarium and Aspergillus growth, the fungi were cultured in media containing various concentrations of NPs from 50 to 1500 ppm. Then, the colony diameter was measured for over 10 days and the growth inhibition percentage was estimated. For statistical analysis, the 600 Mann-Whitney tests have been applied.The NPs were produced after mixing the powdered fungal mass and silver nitrate salt in optimum conditions which were 2 mM of salt, triple fungal mass volume proportion relative to the salt, pH of 9, and temperature of 28 °C. The existence of a peak at 420 nm in FTIR was due to nanoparticle production. Based on the XRD, the synthesized NPs had suitable properties similar to the standard NPs reported in the studies. Images from TEM, SEM, and FESEM microscopes displayed uniform NPs in variable sizes between 25 and 100 nm. According to the results, the maximum growth inhibition percentage of Ag-NPs on Fusarium was approximately 60% at 1500 ppm, and 88% on Aspergillus at 800 ppm. Biosynthesized Ag-NPs with Fusarium oxysporum have desirable structural traits and can inhibit the growth of Fusarium and Aspergillus at significant levels.

Arsenophonus: A Double-Edged Sword of Aphid Defense against Parasitoids.

It is widely accepted that endosymbiont interactions with their hosts have significant effects on the fitness of both pests and beneficial species. A particular type of endosymbiosis is that of beneficial associations. Facultative endosymbiotic bacteria are associated with elements that provide aphids with protection from parasitoids. Arsenophonus (Enterobacterales: Morganellaceae) is one such endosymbiont bacterium, with infections being most commonly found among the Hemiptera species. Here, black cowpea aphids (BCAs), Aphis craccivora Koch (Hemiptera: Aphididae), naturally infected with Arsenophonus, were evaluated to determine the defensive role of this bacterium in BCAs against two parasitoid wasp species, Binodoxys angelicae and Lysiphlebus fabarum (both in Braconidae: Aphidiinae). Individuals of the black cowpea aphids infected with Arsenophonus were treated with a blend of ampicillin, cefotaxime, and gentamicin (Arsenophonus-reduced infection, AR) and subsequently subjected to parasitism assays. The results showed that the presence of Arsenophonus does not prevent BCAs from being parasitized by either B. angelicae or L. fabarum. Nonetheless, in BCA colonies parasitized by B. angelicae, the endosymbiont delayed both the larval maturation period and the emergence of the adult parasitoid wasps. In brief, Arsenophonus indirectly limits the effectiveness of B. angelicae parasitism by decreasing the number of emerged adult wasps. Therefore, other members of the BCA colony can survive. Arsenophonus acts as a double-edged sword, capturing the complex dynamic between A. craccivora and its parasitoids.

Whole genome analysis of a novel Spodoptera exigua nucleopolyhedrovirus isolate (SeMNPV-IR) to Iran.

Baculoviruses are successful microbial control agents used in the biological control of agricultural pest species, especially in the order Lepidoptera. The beet armyworm, Spodoptera exigua is a popular agricultural pest in the world. S exigua larvae, which are active in the all-summer period, cause economic losses by damaging many crops in agricultural production areas. This article aims to analyze the full genome of Spodoptera exigua multiple nucleopolyhedroviruses from Iran (SeMNPV-IR) and to determine the geographical difference between the strains at the genomic level. The full genome of SeMNPV-IR is 135.764 base pairs in length that contained 136 open reading frames (ORFs), and 43.92% G + C content. The seven homologous repeated (hr) regions were identified. In the results of genome-wide phylogenetic analysis, it was determined that the SeMNPV-IR genome isolated from Iran was interestingly close to the genome of the US and Korea isolates. However, there are significant differences in the two hypothetical (Orf 83 and Orf 104) genes. The SeMNPV-IR has a unique homolog repeat region (hr1, 96 bp) that is not found in other SeMNPV genomes, and it also differs in terms of the hr2 region. In silico restriction endonuclease analysis by StuI and SacII enzymes show that there were significant differences between all geographic isolates of SeMNPV. Supplementary Information: The online version contains supplementary material available at 10.1007/s11756-023-01399-2.

Impacts of polyethylene microplastics on the microalga, Spirulina (Arthrospira platensis).

Microalgae play a critical role in the food web and biogeochemical cycling and produce compounds that are commercially exploited. However, their reactions and responses to microplastic contamination are not well understood. In this study, the widely distributed and commercially important cyanobacterium, Spirulina (Arthrospira platensis), was exposed to different concentrations (1-100 mg L-1) of low-density polyethylene microplastics (<5 µm) over a 20-d period. Various end-points were combined with different microscopic techniques in order to examine physiological and biochemical effects and interactions between the plastic and microalga. Growth rate and photosynthetic activity decreased with increasing microplastic concentration, and a maximum inhibition ratio of about 9% was calculated from optical density measurements. Plastic concentrations above 10 mg L-1 resulted in oxidative stress and the intracellular production of proline. Fragmentation and swelling of trichomes and attachment of microplastics was observed in the exposures, and microplastics appeared to adhere or aggregate around fragmented or fragmenting regions. The latter effect may indicate trichome weakening by microplastics or their concentration around cytosolic debris; nevertheless, it provides a potential mechanism for internalisation of small particles. Although unrealistically high concentrations of well-defined microplastics have been employed, relatively small disruptions at the population level incurred by lower concentrations could have more serious implications for ecosystem services and functioning.

Beneficial worm allies warn plants of parasite attack below-ground and reduce above-ground herbivore preference and performance.

Antagonistic interactions among different functional guilds of nematodes have been recognized for quite some time, but the underlying explanatory mechanisms are unclear. We investigated responses of tomato (Solanum lycopersicum) to two functional guilds of nematodes-plant parasite (Meloidogyne javanica) and entomopathogens (Heterorhabditis bacteriophora, Steinernema feltiae below-ground, and S. carpocapsae)-as well as a leaf mining insect (Tuta absoluta) above-ground. Our results indicate that entomopathogenic nematodes (EPNs): (1) reduced root knot nematode (RKN) infestation below-ground, (2) reduced herbivore (T. absoluta) host preference and performance above-ground, and (3) induced overlapping plant defence responses by rapidly activating polyphenol oxidase and guaiacol peroxidase activity in roots, but simultaneously suppressing this activity in above-ground tissues. Concurrently, we investigated potential plant signalling mechanisms underlying these interactions using transcriptome analyses. We found that both entomopathogens and plant parasites triggered immune responses in plant roots with shared gene expression. Secondary metabolite transcripts induced in response to the two nematode functional guilds were generally overlapping and showed an analogous profile of regulation. Likewise, we show that EPNs modulate plant defence against RKN invasion, in part, by suppressing active expression of antioxidant enzymes. Inoculations of roots with EPN triggered an immune response in tomato via upregulated phenylpropanoid metabolism and synthesis of protease inhibitors in plant tissues, which may explain decreased egg laying and developmental performance exhibited by herbivores on EPN-inoculated plants. Furthermore, changes induced in the volatile organic compound-related transcriptome indicated that M. javanica and/or S. carpocapsae inoculation of plants triggered both direct and indirect defences. Our results support the hypothesis that plants "mistake" subterranean EPNs for parasites, and these otherwise beneficial worms activate a battery of plant defences associated with systemic acquired resistance and/or induced systemic resistance with concomitant antagonistic effects on temporally co-occurring subterranean plant pathogenic nematodes and terrestrial herbivores.

Relationship between dietary diversity score and general health in female students.

BACKGROUND: Adolescence is a critical period with respect to mental and psychological issues. The role of nutrients is well known in health condition in adolescents, but little emphasis is placed on total diet quality. Dietary diversity score (DDS) is often used to assess diet quality. The objective of this study was to investigate the relationship between DDS and general health in girl students. METHODS: The present research is a cross-sectional study which used descriptive-analytical approach. A total of 384 high-school female students selected using proportional stratified sampling. Physical activity level, diet and general health information collected using International Physical Activity Questionnaire (IPAQ), Dietary Diversity Questionnaire (FAO-2013) and 28-item self-reported general health questionnaire (GHQ-28), respectively. In addition, weight, height and waist circumference (WC) measured. Data analyzed using Chi-Square test, one-way ANOVA and Multinomial Logistic Regression. RESULTS: Mean DDS was 4.43±1.09. After adjustment for confounders of age, body mass index, physical activity, socioeconomic status and nutritional supplement intake, students with higher DDS were less prone to general health disorders (P≤0.05). CONCLUSIONS: These finding implicate higher DDS in adolescents may associate with better general health.

Entomophilic nematodes, Diploscapter coronatus and Oscheius tipulae from Afghanistan.

Several soil samples from different habitats in Badakhshan province of Afghanistan were collected to isolate and characterize bacteria feeding nematodes. The Galleria mellonella-baiting method was used for the isolation of the Afghan insect-associated nematodes. The nematodes were studied using morphological and morphometric data. The Oscheius specimen was characterized by a longer body (630-820 µm) and shorter pharynx (125-145 µm), whereas other morphological characters were not unusual. The Diploscapter specimen had an annulated cuticle, with lip region width 1.5 times shorter than the stoma, and had separated pharyngeal corpus from the isthmus and vulva located in the middle of the body. The molecular data were derived using three loci; 18S, 28S (D2/D3 segment), and ITS rRNA region, which were utilized to measure the genetic distance. The phylogenetic analysis was conducted to reconstruct the relationship tree. Both morphological and molecular approaches confirmed the identity of nematode isolates as Oscheius tipulae and Diploscapter coronatus. This is the first report of insect-associated nematodes from the soil of Afghanistan. Both species were capable of infecting and killing G. mellonella larvae in less than 96 h.

PET-microplastics as a vector for heavy metals in a simulated plant rhizosphere zone.

Although microplastics (MPs) are ubiquitous contaminants in different ecosystems, their interactions with other pollutants including heavy metals remain relatively unknown. Wheat is an important grain that makes the basis of human food in many parts of the world. Thus, pollutants that affect its production are important subjects of study. This research focuses on the possible effects of the transport of the adsorbed heavy metals onto MPs to the roots of growing wheat. The adsorption of three heavy metals (Pb, Cd, and Zn) onto PET particles was examined. Pb and Cd were selected because they are known to be toxic, while Zn is an essential nutrient for plants. Adsorption experiments were performed using 1 g of PET-MP particles in 20 ml of five different concentrations of each individual element (Pb, Cd, and Zn) (denoted as S-elements). To investigate the antagonistic and synergistic effects of these elements on each other, they were studied collectively with all 3 elements present (denoted as C-elements). Desorption experiments were then performed for three scenarios in which the wheat rhizosphere zone was simulated. Generally, the concentration of the investigated heavy metals adsorption on polyethylene terephthalate (PET) decreased in the order: S-Cd > S-Zn > S-Pb and C-Zn > T-Cd > C-Pb. PET particles exposed to Zn, Cd, and Pb solution adsorbed from 7.2 to 8.5%, 5.3 to 9.8%, and 29.8 to 68.5% of the initial heavy metals concentration, respectively. 11.3 to 15.2%, 12.5 to 23.35%, and 5.5 to 33.6% of the initially adsorbed Zn, Cd, and Pb were desorbed in the wheat rhizosphere zone in the three defined scenarios, respectively. The results show that PET particles can act as a vector in transferring heavy metals to the rhizosphere zone.

Entomopathogenic Nematodes as Potential Biological Control Agents of Subterranean Termite, Microcerotermes diversus (Blattodea: Termitidae) in Iraq.

The infectivity of three species of entomopathogenic nematodes (EPNs) such as Steinernema carpocapsae Weiser (Rhabditida: Steinernematidae), Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), and H. bacteriophora Poinar (IRQ.1 strain) were examined against subterranean termite Microcerotermes diversus (Silvestri) (Blattodea: Termitidae) that is the most economically destructive termite in Iraq. Laboratory and field efficacy of these strains were evaluated to test the feasibility of indigenous EPNs to be used in a biological control program. The biological traits examined included pathogenicity, penetration, and reproduction of EPN species. Filter paper and wood bioassays were conducted using six concentrations: 25, 50, 100, 200, 400, and 600 IJs/termite. In both tests, all strains were virulent against M. diversus workers. The LC50 of S. carpocapsae in both petri dishes and in containers with sawdust was (57.9 and 15.7 IJs/termite) less than both indigenous (274.2 and 60.8 IJs/termite) and commercial (139.6 and 52.6 IJs/termite) Heterorhabditis bacteriophora, respectively. In the field, the percent mortality of the tested workers ranged from 22.5-80 ± 8.3%, 37.5-96.2 ± 8.9%, and 28.7-67.5 ± 6.8% for commercial H. bacteriophora and S. carpocapsae and native H. bacteriophora, respectively. All EPN strains successfully penetrated the M. diversus workers under field conditions, while the results showed that there was a significant difference between the three EPN strains. The percent mortality caused by native H. bacteriophora against termites was higher (43.6 ± 2.7%) than both commercial strains of S. carpocapsae (36.9 ± 1.6%) and H. bacteriophora (29.9 ± 1.4 %). These results highlight the efficiency of EPNs for the control of M. diversus workers.