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Eutrophication and global warming boost the outbreak of cyanobacterial blooms and the spread of invasive cyanobacterial species such as Chrysosporum ovalisporum. Different from the often steady-state conditions under laboratory cultivation, the external input of nutrients in natural water is often intermittent and pulsed, which may affect the response of cyanobacteria. In this study, we cultured C. ovalisporum under two phosphorus treatment patterns: a one-time treatment and a five-time pulsed treatment with the same total dosing. Our results showed that phosphorus deficiency in the water inhibits the growth of C. ovalisporum, thereby significantly reducing its biomass and photosynthetic activity (p < 0.05). In addition, phosphorus deficiency led C. ovalisporum to secrete more exopolysaccharides and alkaline phosphatase. Compared with the one-time treatment, the multiple pulses promoted the absorption of phosphorus by C. ovalisporum and inhibited the synthesis of alkaline phosphatase but had no significant effect on the release of cylindrospermopsin (CYN). We also found that multiple pulses had a more significant growth-promoting effect on C. ovalisporum under low phosphorus concentrations. Our results indicated the overall strong adaptability of C. ovalisporum to dynamic changes in phosphate levels in the water column and provide new insight into the outbreak and dispersal strategies of C. ovalisporum.

The global pollution of microplastics (MPs) has attracted wide attention, and many studies have been conducted on the effects of MP qualities or types and particle sizes on aquatic organisms. However, few studies on the impact of polyethylene terephthalate microplastic (mPET) with different colors on phytoplankton in aquatic ecosystems have been carried out. In this study, mPET of three common colors (green, black, and white) in different concentrations (0, 10, 50, 100, and 200 mg/L) were selected to explore effects on a bloom-forming cyanobacterium Microcystis aeruginosa. The growth, photosynthesis, the number and size of colony, and MC-LR production of M. aeruginosa were studied within a 25-days exposure experiment. The results showed that colors of mPET had significant effects on the growth and photosynthesis of this species but the concentration of mPET had no significant effect. The low concentration of green mPET group promoted algal growth, photosynthesis, and the M. aeruginosa exposed to it was easier to agglomerate into colonies. Moreover, both mPET colors and concentrations have a significant impact on the microcystin production of M. aeruginosa. The low concentration of the green mPET group significantly inhibited the production throughout the experiment, while the white and black mPET significantly increased the concentration of extracellular microcystin (MC-LR). Our results provided new insights into the effects of MPs with different colors and concentrations on the growth and physiology of cyanobacteria and provide basic data for the ecological risk assessment and pollution prevention of MPs.

The Cenozoic deformation history of the Qilian Shan, which is a reactivated fold-thrust belt in the northeastern region of the Tibetan Plateau, is poorly understood but features prominently in the geodynamic mechanism of the evolution of the plateau. The northeastern Qaidam Basin, which is located on the south flank of the Qilian Shan, provides a valuable record of the timing and pattern of the Cenozoic deformation of the Qilian Shan in its synorogenic sediments. This study analyzes the apatite fission-track (AFT) thermochronological signatures of the middle Miocene-Quaternary detrital sediments in the northeastern Qaidam Basin and modern stream sands draining the Qilian Shan as a proxy for the timing of tectonic deformation in the Qilian Shan. Our detrital AFT ages indicate that a Cenozoic initial rapid exhumation event occurred in the Qilian Shan in the late Paleocene-early Eocene (~60–54 Ma), followed by another rapid exhumation event during the middle-late Eocene (~42–38 Ma) and some exhumation during the Oligocene-middle Miocene (~33–14 Ma). Distinct changes in detrital AFT ages at depositional ages of ~12 Ma and ~2.1 Ma suggest that further tectonic deformation affected the Qilian Shan at these times. Our results, along with those of previous studies, suggest that tectonic deformation propagated into the northeastern edge of the Tibetan Plateau almost simultaneously with the India-Asia collision. The spatial evolution of Cenozoic deformation in the Qilian Shan is likely based on the distribution of weak structures in the upper crust.

Mammalian spermatozoa undergo a series of functional changes in the female genital tract before they can fertilize oocytes. Chemokines and their receptors are involved in these complex biological events. However, the detailed molecular mechanisms on the modulation of chemokines on spermatozoa still need to be elucidated. CXCL12, a chemokine, has been widely studied in leukocyte migration and. Here we found that CXCL12 was existent in human cumulus cells and follicular fluid and its receptors CXCR4 and CXCR7 were co-expressed on human spermatozoa. We investigated the effects of CXCL12 on various biological functions of human sperm and which receptor plays a dominant role in these processes. We found that CXCL12 could promote human sperm chemotaxis, motility, penetration in the mucus, acrosome reaction and Ca2+ influx through CXCR4 rather than CXCR7. In addition, the simplified physical model reasonably explained the change of sperm velocity under the influence of CXCL12 concentration gradient, which was identical to their physiological motion patterns.

Global cooling and the uplift of the Tibetan Plateau have long been considered the crucial controls of the climate change in inland Asia since the Cenozoic. However, which of these factors has played the leading role is unknown. To understand climate change and the controlling factors in inland Asia, here, we present new records of clay mineralogy and trace elements of clay fractions from the Neogene sedimentary sequence in the Jiuquan Basin of the northeastern Tibetan Plateau. The clay-mineral records reveal four stages of paleoclimate changes. From ca. 24 Ma to 17 Ma, the low total smectite and (smectite+I/S mixed layers+kaolinite)/(illite+chlorite) and high illite contents suggest weak chemical weathering and hence arid climatic conditions. For ca. 17–14 Ma, the high total smectite and (total smectite+kaolinite)/(illite+chlorite) and low illite contents suggest strong chemical weathering, indicating a change in climate from cold and dry to warm and humid. There was no palygorskite during this warm and humid period. From ca. 14 Ma to 8 Ma, the low total smectite content, high illite content and the appearance of palygorskite indicate that the climate turned to cold and dry. Since 8 Ma, low total smectite as well as high illite and chlorite contents suggest a colder and drier period. The records of clay mineralogy illustrate that the Jiuquan Basin has experienced increasing aridity since ca. 14 Ma, synchronous with the inland Asian aridification. Given the synchroneity with the global cooling, we suggest that the climate evolution in the Jiuquan Basin from the late Oligocene to middle-late Miocene was mainly controlled by global climate change. Since the late Miocene, the uplift of the Tibetan Plateau and global cooling have significantly influenced the decreasing temperature and humidity of the Jiuquan Basin. The uplift of Tibetan Plateau may intensify the aridity by blocking moisture from reaching the Jiuquan Basin.