Eutrophication increases the similarity of cyanobacterial community features in lakes and reservoirs.

Eutrophication of inland waters is a mostly anthropogenic phenomenon impacting aquatic biodiversity worldwide, and might change biotic community structure and ecosystem functions. However, little is known about the patterns of cyanobacterial community variations and changes both on alpha and beta diversity levels in response to eutrophication. Here, we investigated cyanobacterial communities sampled at 140 sites from 59 lakes and reservoirs along a strong eutrophication gradient in eastern China through using CPC-IGS and 16S rRNA gene amplicon sequencing. We found that taxonomic diversity increased, but phylogenetic diversity decreased significantly along the eutrophication gradient. Both niche width and niche overlap of cyanobacteria significantly decreased from low- to high-nutrient waterbodies. Cyanobacterial community distance-decay relationship became weaker from mesotrophic to hypereutrophic waterbodies, while ecological uniqueness (i.e., local contributions to beta diversity) tended to increase in high-nutrient waterbodies. Latitude and longitude were more important in shaping cyanobacterial community structure than other environmental variables. These findings suggest that eutrophication affects alpha and beta diversity of cyanobacterial communities, leading to increasingly similar community structures in lakes and reservoirs with a higher level of eutrophication. Our work highlights how cyanobacterial communities respond to anthropogenic eutrophication and calls for an urgent need to develop conservation and management strategies to control lake eutrophication and protect freshwater biodiversity.

Predictors of favorable outcome and mortality after endovascular thrombectomy in young Chinese patients with large vascular occlusions.

Background: Endovascular thrombectomy (EVT) has evolved into the standard treatment for patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO). However, little information is available on the management of EVT in young patients with AIS-LVO in China. The purpose of this study was to assess the favorable outcomes and mortality rates after 90 days of EVT in young Chinese patients with AIS-LVO and their predictors. Methods: This retrospective study included young Chinese patients aged 18-50 years with AIS-LVO. The primary efficacy endpoint was the modified Rankin scale (mRS) score at day 90, and the primary safety endpoint was mortality within 90 days. Using univariate and multivariate logistic regression analyses, the associations between clinical, imaging, and procedure variables and favorable (mRS 0-2) outcomes or mortality at 90 days were analyzed. Results: A total of 113 patients were included in the study with a mean age of 43.1 ± 6.3 years. Symptomatic intracranial hemorrhage (sICH) occurred in 8 (7.1%) patients. Favorable functional outcomes (mRS 0-2) were recovered in 42.5% of patients at 3 months. After 90 days, the mortality rate was 32.3%. Multivariate analysis revealed that the increase in admission NIHSS score was associated with a lower probability of functional independence (aOR 1.08, 95% CI 1.02-1.15, p = 0.01 and aOR 1.01, 95% CI 1-1.01, p = 0.008, respectively) and a higher probability of death at 90 days (aOR 1.1, 95% CI 1.03-1.18, p = 0.007 and aOR 1.00, 95% CI 1-1.01, p = 0.021, respectively). Conclusion: This study demonstrate that EVT provides higher rates of arterial recanalization, rather than better favorable outcomes and lower risk of death at 3 months in young Chinese patients with AIS-LVO. Increased NIHSS scores on admission may be associated with poor patient prognosis.

Live tracking metabolic networks and physiological responses within microbial assemblages at single-cell level.

Microbial interactions impact the functioning of both natural and engineered systems, yet our ability to directly monitor these highly dynamic and spatially resolved interactions in living cells is very limited. Here, we developed a synergistic approach coupling single-cell Raman microspectroscopy with 15N2 and 13CO2 stable isotope probing in a microfluidic culture system (RMCS-SIP) for live tracking of the occurrence, rate, and physiological shift of metabolic interactions in active microbial assemblages. Quantitative and robust Raman biomarkers specific for N2 and CO2 fixation in both model and bloom-forming diazotrophic cyanobacteria were established and cross-validated. By designing a prototype microfluidic chip allowing simultaneous microbial cultivation and single-cell Raman acquisition, we achieved temporal tracking of both intercellular (between heterocyst and vegetative cells of cyanobacteria) and interspecies N and C metabolite exchange (from diazotroph to heterotroph). Moreover, single-cell N and C fixation and bidirectional transfer rate in living cells were quantified via SIP-induced characteristic Raman shifts. Remarkably, RMCS captured physiological responses of metabolically active cells to nutrient stimuli through comprehensive metabolic profiling, providing multimodal information on the evolution of microbial interactions and functions under fluctuating conditions. This noninvasive RMCS-SIP is an advantageous approach for live-cell imaging and represents an important advancement in the single-cell microbiology field. This platform can be extended for real-time tracking of a wide range of microbial interactions with single-cell resolution and advances the understanding and manipulation of microbial interactions for societal benefit.

Interaction between Raphidiopsis raciborskii and rare bacterial species revealed by dilution-to-extinction experiments.

Interactions between heterotrophic bacteria and cyanobacteria regulate the structure and function of aquatic ecosystems and are thus crucial for the prediction and management of cyanobacterial blooms in relation to water security. Currently, abundant bacterial species are of primary concern, while the role of more diverse and copious rare species remains largely unknown. Using a dilution-to-extinction approach, rare bacterial species from reservoir water were co-cultured with the bloom-forming cyanobacterium Raphidiopsis raciborskii in the lab to explore their interactions by using Phyto-PAM and 16S rRNA gene high-throughput sequencing. We found that a ≤1000-fold bacterial dilution led to bacteria control of the growth and photosynthesis of R. raciborskii. Moreover, the bacterial community compositions in the low-dilution groups were clearly diverged from the high-dilution groups. Importantly, rare species changed dramatically in the low-dilution groups, resulting in lower phylogenetic diversity and narrower niche width. The network complexity and compositional stability of bacterial communities decreased in the low-dilution groups. Collectively, our results suggest that rare bacterial species inhibit R. raciborskii growth and photosynthesis through microbial interactions mediated by species coexistence and interaction mechanisms. Our study provides new knowledge of the ecological role of rare bacteria and offers new perspectives for understanding the outbreak and regression of R. raciborskii blooms.

Biogeographical Patterns of Bacterial Communities and Their Antibiotic Resistomes in the Inland Waters of Southeast China.

Freshwater ecosystems are important sources of drinking water and provide natural settings for the proliferation and dissemination of bacteria and antibiotic resistance genes (ARGs). However, the biogeographical patterns of ARGs in natural freshwaters and their relationships with the bacterial community at large scales are largely understudied. This is of specific importance because data on ARGs in environments with low anthropogenic impact is still very limited. We characterized the biogeographical patterns of bacterial communities and their ARG profiles in 24 reservoirs across southeast China using 16S rRNA gene high-throughput sequencing and high-throughput-quantitative PCR, respectively. We found that the composition of both bacterial communities and ARG profiles exhibited a significant distance-decay pattern. However, ARG profiles displayed larger differences among different water bodies than bacterial communities, and the relationship between bacterial communities and ARG profiles was weak. The biogeographical patterns of bacterial communities were simultaneously driven by stochastic and deterministic processes, while ARG profiles were not explained by stochastic processes, indicating a decoupling of bacterial community composition and ARG profiles in inland waters under relatively low-human-impact at a large scale. Overall, this study provides an overview of the biogeographical patterns and driving mechanisms of bacterial community and ARG profiles and could offer guidance and reference for the control of ARGs in drinking water sources. IMPORTANCE Antibiotic resistance has been a serious global threat to environmental and human health. The "One Health" concept further emphasizes the importance of monitoring the large-scale dissemination of ARGs. However, knowledge about the geographical patterns and driving mechanisms of bacterial communities and ARGs in natural freshwater environments is limited. This study uncovered the distinct biogeographical patterns of bacterial communities and ARG profiles in inland waters of southeast China under low-anthropogenic impact at a large scale. This study improved our understanding of ARG distribution in inland waters with emphasis on drinking water supply reservoirs, therefore providing the much-needed baseline information for future monitoring and risk assessment of ARGs in drinking water resources.

Precision early detection of invasive and toxic cyanobacteria: A case study of Raphidiopsis raciborskii.

Blooms of the toxic cyanobacterium, Raphidiopsis raciborskii (basionym Cylindrospermopsis raciborskii), are becoming a major environmental issue in freshwater ecosystems globally. Our precision prevention and early detection of R. raciborskii blooms rely upon the accuracy and speed of the monitoring method. A duplex digital PCR (dPCR) monitoring approach was developed and validated to detect the abundance and toxin-producing potential of R. raciborskii simultaneously in both laboratory spiked and environmental samples. Results of dPCR were strongly correlated with traditional real time quantitative PCR (qPCR) and microscopy for both laboratory and environmental samples. However, discrepancies between methods were observed when measuring R. raciborskii at low abundance (1 - 105 cells L - 1), with dPCR showing a higher precision compared to qPCR at low cell concentration. Furthermore, the dPCR assay had the highest detection rate for over two hundred environmental samples especially under low abundance conditions, followed by microscopy and qPCR. dPCR assay had the advantages of simple operation, time-saving, high sensitivity and excellent reproducibility. Therefore, dPCR would be a fast and precise monitoring method for the early warning of toxic bloom-forming cyanobacterial species and assessment of water quality risks, which can improve prediction and prevention of the impacts of harmful cyanobacterial bloom events in inland waters.

catena-Poly[[(ethane-diol-κ²O,O')zinc]-µ-oxalato-κ4O¹,O²:O¹',O²'].

In the title complex, [Zn(C2O4)(C2H6O2)](n), the Zn(II) ion is in a distorted octa-hedral environment formed by two O atoms from an ethyl-ene glycol mol-ecule and four O atoms from two oxalate anions. The oxalate anions link the Zn(II) ions, forming a zigzag chain along [010]. The zigzag chains are extended into a three-dimensional network by O-H⋯O hydrogen bonds.

4-(1H-Pyrazol-3-yl)pyridine-terephthalic acid-water (2/1/2).

In the title compound, 2C(8)H(7)N(3)·C(8)H(6)O(4)·2H(2)O, the pyridine and pyrazole rings are approximately coplanar, the dihedral angle between them being 4.69 (9)°. The asymmetric unit consists of half of the terephthalic acid (an inversion centre generates the other half of the mol-ecule), one 4-(1H-pyrazol-3-yl)pyridine (4pp) mol-ecule and one water mol-ecule. In the crystal, two 4pp and one terephthalic acid mol-ecules form a linear three-molecule unit as a result of O-H⋯N hydrogen bonds. These units are further assembled into a three-dimensional network by two types of hydrogen bonds, viz. O-H⋯O and N-H⋯O.

Dichloridobis[4-(1H-pyrazol-3-yl)pyridine-κN]zinc.

In the title compound, [ZnCl(2)(C(8)H(7)N(3))(2)], the Zn(II) cation is coordinated by two Cl(-) anions and two 4-(1H-pyrazol-3-yl)pyridine ligands in a distorted tetra-hedral geometry. In the two 4-(1H-pyrazol-3-yl)pyridine ligands, the dihedral angles between the pyrazole and pyridine rings are 3.3 (3) and 13.3 (3)°. Inter-molecular N-H⋯N and N-H⋯Cl hydrogen bonding is present in the crystal structure.

catena-Poly[[(acetato-κO)[4-(1H-pyrazol-3-yl)pyridine-κN]zinc]-µ-acetato-κO:O'].

In the title compound, [Zn(CH(3)CO(2))(2)(C(8)H(7)N(3))](n), the Zn(II) atom is coordinated by one N atom from a 4-(1H-pyrazol-3-yl)pyridine ligand and three O atoms from two bridging and one terminal acetate ligands, forming a distorted tetra-hedral geometry. The bridging acetate ligands link the Zn atoms into a chain along [001]. N-H⋯O hydrogen bonds and π-π inter-actions between the pyridine and pyrazole rings [centroid-centroid distance = 3.927 (3) Å] connect the chains into a layer parallel to (011).