Micro/nano-plastics and microalgae in aquatic environment: Influence factor, interaction, and molecular mechanisms.

Micro/nano-plastics, as emerging persistent pollutant, are frequently detected in aquatic environments together with other environmental pollutants. Microalgae are the major primary producers and bear an important responsibility for maintaining the balance of aquatic ecosystems. Numerous studies have been conducted on the influence of micro/nano-plastics on the growth, photosynthesis, oxidative stress, gene expression and metabolites of microalgae in laboratory studies. However, it is difficult to comprehensively evaluate the toxic effects of micro/nano-plastics on microalgae due to different experimental designs. Moreover, there is a lack of effective analysis of the aforementioned multi-omics data and reports on shared biological patterns. Therefore, the purpose of this review is to compare the acute, chronic, pulsed, and combined effect of micro/nano-plastics on microalgae and explore hidden rules in the molecular mechanisms of the interaction between them. Results showed that the effect of micro/nano-plastics on microalgae was related to exposure mode, exposure duration, exposure size, concentration, and type of micro/nano-plastics. Meanwhile, the phenomenon of poisoning and detoxification between micro/nano-plastics and microalgae was found. The inhibitory mechanism of micro/nano-plastics on algal growth was due to the micro/nano-plastics affected the photosynthesis, oxidative phosphorylation, and ribosome pathways of algal cells. This brought the disruption of the functions of chloroplasts, mitochondria, and ribosome, as well as impacted on energy metabolism and translation pathways, eventually leading to impairment of cell function. Besides, algae resisted this inhibitory effect by regulating the alanine, aspartate, and glutamate metabolism and purine metabolism pathways, thereby increasing the chlorophyll synthesis, inhibiting the increase of reactive oxygen species, delaying the process of lipid peroxidation, balancing the osmotic pressure of cell membrane.

Using a theoretical approach to predict college students' non-medical use of prescription drugs - a survival analysis.

OBJECTIVES: This study assesses students' non-medical use of prescription drugs (NMUPD) from college entrance to graduation, and examines factors that predict NMUPD. Participants: The study was conducted between May 2011 and September 2015 with 338 students. Methods: Longitudinal cohort study design was used to examine NMUPD across time, and NMUPD-related attitudes and subjective norms. Five yearly interviews were conducted to collect data. Cox proportional hazards regression analysis was used to examine time to NMUPD. Results: Thirty-five percent of study participants reported NMUPD; the majority of those initiated non-medical use before their third year in college. Analyses indicated that more positive attitudes towards NMUPD (HR = 1.73, p < 0.001), increased subjective norms regarding NMUPD (HR = 1.01, p < 0.01), and gender (male) (HR= 1.89, p < 0.001) were significantly associated with sooner NMUPD. Conclusions: Findings suggest that NMUPD prevention efforts that target mutable factors such as attitudes and subjective norms should be implemented early during students' college careers.

Melatonin modulates monochromatic light-induced melatonin receptor expression in the hypothalamus of chicks.

To study the mechanism of the effect of monochromatic light on physiological function in chicken, a total of 192 newly hatched chicks were randomly divided into intact, sham-operated and pinealectomy groups then exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) using a light-emitting diode (LED) system for two weeks. At P14, the hypothalami were immediately collected for immunohistochemical staining of melatonin receptor subtypes (Mel1a and Mel1b) and detection of Mel1a and Mel1b expressions using RT-PCR and western blot. Immunohistochemical staining of the hypothalamus showed that the Mel1a-ir cells were distributed in the preoptic area (POA), nucleus preopticus periventricularis (POP) and suprachiasmatic nuclei (SCN), and the Mel1b-ir cells were presented in the POA and SCN. Analysis of RT-PCR and western blot showed that the mRNA and protein levels of Mel1a and Mel1b in the hypothalamus of chick exposed to GL were increased by 10.7-29.3%, 9.18-35.9% and 8.97-27.3% compared to those in the chicks exposed to WL (P=0.029-0.002), RL (P=0.027-0.001) and BL (P=0.038-0.007) in the intact group, respectively. After pinealectomy, however, these parameters decreased and there were no significant differences among the WL, RL, GL and BL groups. These findings suggested that melatonin plays a critical role in GL illumination-enhanced Mel1a and Mel1b expressions in the hypothalamus of chicks.

Direct detection of malaria infected red blood cells by surface enhanced Raman spectroscopy.

Surface enhanced Raman spectra (SERS) of normal red blood cells (RBCs) and Plasmodium falciparum infected RBCs (iRBCs) at different post invasion time were obtained based on silver nanorod array substrates. Distinct spectral differences were observed due to the cell membrane modification of RBCs during malaria infection. The SERS spectra of ring stage iRBCs had a characteristic Raman peak at Δv=1599cm(-1) as compared to those of normal RBCs, while the trophozoite and schizoid stages had identical SERS spectra with a characteristic peak at Δv=723cm(-1), which is significantly different from ring stage iRBCs, consistent with ongoing modification of the iRBC membrane. Since ring stage iRBCs of P. falciparum are found circulating in blood, such a difference provides a new strategy for rapid malaria detection. The limit of detection as well as the ability to detect a mixed iRBC and RBC solution was also investigated.

Mitochondrial- and Fas-L-mediated pathways involved in quinestrol induced spermatogenic apoptosis in adult rat testes.

The pathways involved in quinestrol-induced spermatogenic apoptosis were studied in adult male rat by using daily intragastric administration of 0.01 mg/kg, 0.1 mg/kg and 1 mg/kg body weight quinestrol for two consecutive weeks. The immunohistochemistry staining was performed to measure the expression of proliferating cell nuclear antigen (PCNA), caspase-3, Bax, Bcl-2, Fas and FasL. The results showed that testes weights and the size of seminiferous tubule (ST) decreased as well as the organization of the ST changed significantly after treatment with 1 mg/kg quinestrol. The number of germ cells expressing caspase-3, Bax, Fas and FasL markedly increased whereas the numbers of cells expressing Bcl-2 and PCNA significantly decreased in the group treated with quinestrol at 1 mg/kg compared with the control. The results suggest that quinestrol induced abnormal spermatogenesis through the mitochondrial- and Fas-L-mediated pathways after quinestrol exposure in male rat.

Quinestrol induces spermatogenic apoptosis in vivo via increasing pro-apoptotic proteins in adult male mice.

The effects of quinestrol on spermatogenesis were investigated in adult male mice by daily intragastric administration of quinestrol with various doses of 5, 10, 50 and 100mg/kg body weight for 10 days. The sperm counts declined while the number of abnormal spermatozoa went up in mice treated with quinestrol. The testicular weight and seminiferous tubular area gradually declined with increasing dosages of quinestrol to 50 and 100mg/kg. Rarefied germ cells showed irregular distributions in the seminiferous tubules of mice treated with 50 and 100mg/kg quinestrol. Apoptosis was highly pronounced in spermatogonia, spermatocytes, spermatids and Leydig cells. Antioxidant enzyme activities - superoxide dismutase and glutathione peroxidase - as well as total antioxidant capacity significantly reduced, while malondialdehyde contents increased. The number of germ cells expressing caspase-3, p53, Bax and FasL significantly increased whereas cells expressing Bcl-2 significantly decreased in groups treated with 50 and 100mg/kg quinestrol compared with the control. The concentration of nitrogen monoxidum also increased significantly under these dosages. The results suggest that quinestrol stimulates oxidative stress to induce apoptosis in spermatogenic cells through the mitochondrial and death receptor pathways in adult male mice.