Search

Many plastics cause pollution in the marine environment, with microplastics (0.1 µm-5 mm) representing a key research focus. The number of microplastics in sediments may increase rapidly, affecting organisms inhabiting marine sediments. The aim of this study was to determine how microplastics affect nematodes in intertidal sand. We assessed: (1) intake of microplastic particles (10 µm, 5 µm, 1 µm, or 0.5 µm) by Enoplolaimus spp. over 48 h; (2) microplastic intake by nematodes depending on feeding type (selective deposit feeders, non-selective deposit feeders, epistrate feeders, or predators/omnivores) over 48 h; and (3) microplastic egestion by Enoplolaimus spp. The proportion of Enoplolaimus spp. individuals containing microplastics was significantly less in the 10-µm microplastic treatment than in the treatments where Enoplolaimus spp. were exposed to microplastic particles of smaller sizes (5 µm, 1 µm, or 0.5 µm). The ingestion rates of microplastics by predators/omnivores, non-selective deposit feeders, and selective deposit feeders increased as the size of the microplastic decreased. After transferring Enoplolaimus spp. to filtered seawater following microplastic ingestion, the proportion of Enoplolaimus spp. individuals containing the smallest size microplastic (0.5 µm) decreased by 15% of the ingested amount in 3 days. In conclusion, there was a significant difference among microplastic-size treatments, but not among feeding types or in the interaction between microplastic size and feeding type. The size of microplastics, rather than feeding type of nematodes, impacted ingestion rates. It is possible that microplastics in the sediment are ingested by nematodes living in marine benthic ecosystems. [ABSTRACT FROM AUTHOR]

The release of antibiotics to the environment after use by fish farms could have potentially negative effects. Here, we assessed how the antibiotic oxytetracycline (OTC) affect the meiofaunal communities of Jeju Island in Korea. We assessed how: 1) nematodes responded to 0-2000 ppm OTC over 48 h; 2) Metoncholaimus spp. (the most abundant group) responded to 0-500 ppm OTC over 48 h; and 3) the meiofaunal community responded to 0-200 ppm OTC for 1-month. In experiment 1, all nematodes died at high antibiotic concentrations (1000 ppm, 2000 ppm), but death rates rapidly decreased at 500 ppm (42%) and below (0-9%). In experiment 2, Metoncholaimus spp. death rates were similar to those documented in experiment 1 for OTC concentrations of 500 ppm (45%) and decreased at 125 ppm and 250 ppm (to 30% and below). In experiment 3, long-term exposure to low concentrations (200 ppm or less) of OTC did not have a strong effect on meiofaunal density, with meiofaunal density in the experimental group showing no decline with OTC concentration. However, we confirmed that differences in OTC concentration affects the structure of meiofaunal communities, making it important to regulate their use by fish farms. [ABSTRACT FROM AUTHOR]

In this study, we investigated plasma initiation delay times for argon volume breakdown at the W-band frequency regime. The threshold electric field is defined as the minimum electric field amplitude needed for plasma breakdown at various pressures. The measured statistical delay time showed an excellent agreement with the theoretical Gaussian distribution and the theoretically estimated formative delay time. Also, we demonstrated that the normalized effective electric field as a function of the product of pressure and formative time shows an outstanding agreement to that of 1D particle-in-cell simulation coupled with a Monte Carlo collision model [H. C. Kim and J. P. Verboncoeur, Phys. Plasmas 13, 123506 (2006)]. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the author discusses articles within the issue on topics that include the collaboration of the World Council of Churches (WCC) and ACT Alliance in working for justice and peace, the concept of ecumenical diakonia, and responses of the modern church's diakonia to crises in today's world.

The article offers information the role of the diaconal community with the World Council of Churches (WCC) in relation to the pilgrimage of justice and peace. Topics include an examination of the ecumenical understanding of diakonia, diakonia as an expression of the churches' role in the mission of God, and its aspect of service in the community. It also discusses the dimension of diakonia of care and advocacy for creation.

The discovery of small-molecule inhibitors requires suitable binding pockets on protein surfaces. Proteins that lack this feature are considered undruggable and require innovative strategies for therapeutic targeting. KRAS is the most frequently activated oncogene in cancer, and the active state of mutant KRAS is such a recalcitrant target. We designed a natural product–inspired small molecule that remodels the surface of cyclophilin A (CYPA) to create a neomorphic interface with high affinity and selectivity for the active state of KRASG12C (in which glycine-12 is mutated to cysteine). The resulting CYPA:drug:KRASG12C tricomplex inactivated oncogenic signaling and led to tumor regressions in multiple human cancer models. This inhibitory strategy can be used to target additional KRAS mutants and other undruggable cancer drivers. Tricomplex inhibitors that selectively target active KRASG12C or multiple RAS mutants are in clinical trials now (NCT05462717 and NCT05379985). [ABSTRACT FROM AUTHOR]

Although endogenous rhythms such as diel and tidal effects can influence the distribution of sandy beach amphipods, the consequences of these for the seasonal endogenous rhythms of amphipods within the subtidal surf zone of sandy beaches are little understood. We examined the seasonal variation in diel and tidal effects among benthic amphipods with different lifestyles in a sandy shore surf zone in southern Korea. Using a sledge net, quantitative samples of amphipods were taken for 24 h at three stations: at the bottom and surface at a water depth of 1 m, and at the water's edge. The epifaunal, nestling amphipods, Pontogeneia rostrata Gurjanova, 1938 and Allorchestes angusta Dana, 1856 and the burrower, Haustorioides koreanus Jo, 1988 were significantly more abundant at the surface at night than during the day, suggesting nocturnal vertical migration. However, the abundance of the burrower, Synchelidium lenorostralum Hirayama, 1986 did not change between day and night, suggesting that this species did not perform vertical migrations. Most of the amphipods, particularly P. rostrata, showed a seasonally different response to tidal effects, appearing at higher densities during ebbing than flooding tides in one or more seasons, and depending on the species. Amphipods increased in abundance at night regardless of seasonal tidal variation, suggesting that the diel effect may be more important than the tidal effect. Seasonal variation to diel and tidal effects by these amphipods varied with temperature and different lifestyles. [ABSTRACT FROM AUTHOR]

Hypoxia in bottom environments of coastal marine ecosystems is a serious problem adversely affecting both benthic life and local fisheries. In this study, we monitored abundance, composition, and feeding types of nematode communities under pre-, mid-, and post-hypoxic conditions in Omura Bay, Nagasaki, Japan, for three consecutive years (2013-2015). The bay is almost completely enclosed, and experiences hypoxia at the bottom every summer. A positive correlation was found between dissolved oxygen (DO) concentration and nematode abundance over the entire sampling period (p<0.05, r=0.61). The nematode community compositions among the pre-, mid-, and post-hypoxic conditions were significantly different (one-way analysis of similarities (ANOSIM), p<0.05), which suggests that DO in the bottom water acts as a major driver for the community shift. The increases in abundance of nematodes with toothless feeding apparatus in hypoxic periods, relative to normoxic periods, further suggested that the transfer of organic matter from bacteria through nematodes became more important in the bay under hypoxia than normoxia. It was also demonstrated that full recovery of nematode populations from hypoxic to normoxic conditions would require more than two weeks of continuous normoxic DO levels (>3 mg L-1). These findings will help us to understand how global trends of ocean deoxygenation could shape the meiobenthic community and alter benthic ecosystem functioning in coastal areas. [ABSTRACT FROM AUTHOR]

Hexanucleotide repeat expansion in the C9orf72 gene is a leading cause of frontotemporal lobar degeneration (FTLD) with amyotrophic lateral sclerosis (ALS). Reduced expression of C9orf72 has been proposed as a possible disease mechanism. However, the cellular function of C9orf72 remains to be characterized. Here we report the identification of two binding partners of C9orf72: SMCR8 and WDR41. We show that WDR41 interacts with the C9orf72/SMCR8 heterodimer and WDR41 is tightly associated with the Golgi complex. We further demonstrate that C9orf72/SMCR8/WDR41 associates with the FIP200/Ulk1 complex, which is essential for autophagy initiation. C9orf72 deficient mice, generated using the CRISPR/Cas9 system, show severe inflammation in multiple organs, including lymph node, spleen and liver. Lymph node enlargement and severe splenomegaly are accompanied with macrophage infiltration. Increased levels of autophagy and lysosomal proteins and autophagy defects were detected in both the spleen and liver of C9orf72 deficient mice, supporting an in vivo role of C9orf72 in regulating the autophagy/lysosome pathway. In summary, our study elucidates potential physiological functions of C9orf72 and disease mechanisms of ALS/FTLD. [ABSTRACT FROM AUTHOR]