Competitive effects of the macroalga Caulerpa taxifolia on key physiological processes in the scleractinian coral Turbinaria peltata under thermal stress.

An increased abundance of macroalgae has been observed in coral reefs damaged by climate change and local environmental stressors. Macroalgae have a sublethal effect on corals that includes the inhibition of their growth, development, and reproduction. Thus, this study explored the effects of the macroalga, Caulerpa taxifolia, on the massive coral, Turbinaria peltata, under thermal stress. We compared the responses of the corals' water-meditated interaction with algae (the co-occurrence group) and those in direct contact with algae at two temperatures. The results show that after co-culturing with C. taxifolia for 28 days, the density content of the dinoflagellate endosymbionts was significantly influenced by the presence of C. taxifolia at ambient temperature (27 °C), from 1.3 × 106 cells cm-2 in control group to 0.95 × 106 cells cm-2 in the co-occurrence group and to 0.89 × 106 cells cm-2 in the direct contact group. The chlorophyll a concentration only differed significantly between the control and the direct contact group at 27 °C. The protein content of T. peltata decreased by 37.2% in the co-occurrence group and 49.0% in the direct contact group compared to the control group. Meanwhile, the growth rate of T. peltata decreased by 57.7% in the co-occurrence group and 65.5% in the direct contact group compared to the control group. The activity of the antioxidant enzymes significantly increased, and there was a stronger effect of direct coral contact with C. taxifolia than the co-occurrence group. At 30 °C, the endosymbiont density, chlorophyll a content, and growth rate of T. peltata significantly decreased compared to the control temperature; the same pattern was seen in the increase in antioxidant enzyme activity. Additionally, when the coral was co-cultured with macroalgae at 30 °C, there was no significant decrease in the density or chlorophyll a content of the endosymbiont compared to the control. However, the interaction of macroalgae and elevated temperature was evident in the feeding rate, protein content, superoxide dismutase (SOD), and catalase (CAT) activity compared to the control group. The direct contact of the coral with macroalga had a greater impact than water-meditated interactions. Hence, the competition between coral and macroalga may be more intense under thermal stress.

Phylogeny of Oriental voles (Rodentia: Muridae: Arvicolinae): molecular and morphological evidence.

The systematics of Oriental voles remains controversial despite numerous previous studies. In this study, we explore the systematics of all species of Oriental voles, except Eothenomys wardi, using a combination of DNA sequences and morphological data. Our molecular phylogeny, based on two mitochondrial genes (COI and cyt b), resolves the Oriental voles as a monophyletic group with strong support. Four distinct lineages are resolved: Eothenomys, Anteliomys, Caryomys, and the new subgenus Ermites. Based on morphology, we consider Caryomys and Eothenomys to be valid genera. Eothenomys, Anteliomys, and Ermites are subgenera of Eothenomys. The molecular phylogeny resolves subgenera Anteliomys and Ermites as sister taxa. Subgenus Eothenomys is sister to the clade Anteliomys + Ermites. Caryomys is the sister group to genus Eothenomys. Further, the subspecies E. custos hintoni and E. chinensis tarquinius do not cluster with E. custos custos and E. chinensis chinensis, respectively, and the former two taxa are elevated to species level and assigned to the new subgenus Ermites.

Effects of Caulerpa taxifolia on Physiological Processes and Gene Expression of Acropora hyacinthus during Thermal Stress.

An increasing ecological phase shift from coral-dominated reefs to macroalgae-dominated reefs as a result of anthropogenic impacts, such as eutrophication, sedimentation, and overfishing, has been observed in many reef systems around the world. Ocean warming is a universal threat to both corals and macroalgae, which may alter the outcome of competition between them. Therefore, in order to explore the effects of indirect and direct exposure to macroalgae on the physiological, biochemical, and genetic expression of corals at elevated temperature, the coral Acropora hyacinthus and highly invasive green algae Caulerpa taxifolia were chosen. Physiologically, the results exhibited that, between the control and direct contact treatments, the density and chlorophyll a content of zooxanthella decreased by 53.1% and 71.2%, respectively, when the coral indirectly contacted with the algae at an ambient temperature (27 °C). Moreover, the enzyme activities of superoxide dismutase (SOD) and catalase (CAT) in coral tissue were enhanced by interacting with algae. After an increase of 3 °C, the density and chlorophyll a content of the zooxanthella reduced by 84.4% and 93.8%, respectively, whereas the enzyme activities of SOD and CAT increased 2.3- and 3.1-fold. However, only the zooxanthellae density and pigment content decreased when Caulerpa taxifolia was co-cultured with Acropora hyacinthus at 30 °C. Molecularly, different from the control group, the differentially expressed genes (DEGs) such as Rab family, ATG family, and Casp7 genes were significantly enriched in the endocytosis, autophagy, and apoptosis pathways, regardless of whether Acropora hyacinthus was directly or indirectly exposed to Caulerpa taxifolia at 27 °C. Under thermal stress without algae interaction, the DEGs were significantly enriched in the microbial immune signal transduction pathways, such as the Toll-like receptor signaling pathway and TNF signaling pathway, while multiple cellular immunity (IFI47, TRAF family) and oxidative stress (CAT, SODC, HSP70) genes were upregulated. Inversely, compared with corals without interaction with algae at 30 °C, the DEGs of the corals that interacted with Caulerpa taxifolia at 30 °C were remarkably enriched in apoptosis and the NOD-like receptor signaling pathway, including the transcription factors such as the Casp family and TRAF family. In conclusion, the density and chlorophyll a content of zooxanthella maintained a fading tendency induced by the macroalgae at ambient temperatures. The oxidative stress and immune response levels of the coral was elevated at 30 °C, but the macroalgae alleviated the negative effects triggered by thermal stress.

Taxonomic position of Chinese voles of the tribe Arvicolini and the description of 2 new species from Xizang, China.

China has 26 species in the tribe Arvicolini. The taxonomic status of these voles remains controversial despite much effort. Herein, we evaluate the taxonomic position of 22 species plus 2 unidentified taxa using mitochondrial DNA gene sequences (cytb + CO1). We also evaluate 18 species and 2 unidentified taxa using morphological data. Phylogenetic analyses of cytb resolve monophyly for the genera Alexandromys, Lasiopodomys, Microtus, Neodon, Proedromys, and Volemys with strong support. Stenocranius clusters with Chionomys but with very weak support. Analyses of concatenated cytb + CO1 resolve the same genera with strong support, but the topology of the tree differs from that of cytb in that Chionomys roots at the base of the tree independent of Stenocranius, which forms the sister-group of Lasiopodomys in a more terminal position. The matrilineal genealogy excludes the type species Arvicola amphibius from the rest of the Arvicolini. This species forms the sister-group of Ondatra with high support. Neodon includes N. irene, N. linzhiensis, N. fuscus, N. leucurus, N. sikimensis, Microtus clarkei, and 2 unidentified specimens. Alexandromys includes the former species Microtus oeconomus, M. kikuchii, M. limnophilus, M. fortis, and M. maximowiczii. Finally, Microtus has the subgenera Blanfordimys, Microtus, Mynomes, Pedomys, Pitymys, and Terricola, which includes the Chinese species M. agrestis, M. arvalis, and Blanfordimys juldaschi. General mixed Yule-coalescent species delimitation modeling demarcates 6 currently recognized species and 2 new species of Neodon. A principal component analysis of the morphological data among 7 matrilines shows that all variables have positive loadings of high magnitude on the 1st component. Canonical discriminant analysis for Neodon (including M. clarkei and 2 unidentified species) correctly classifies 93.0% of specimens. Overall, our analyses support the recognition of Alexandromys, Lasiopodomys, Microtus, Neodon, Proedromys, and Volemys as genera. Stenocranius includes Microtus gregalis, and the genealogical position of Stenocranius remains uncertain. The status of Arvicola requires further study. We assign M. clarkei to Neodon and describe 2 new species of Neodon.

A compositional shift in the soil microbiome induced by tetracycline, sulfamonomethoxine and ciprofloxacin entering a plant-soil system.

Antibiotics entering the soil likely disturb the complex regulatory network of the soil microbiome, which is closely associated with soil quality and ecological function. This study investigated the effects of tetracycline (TC), sulfamonomethoxine (SMM), ciprofloxacin (CIP) and their combination (AM) on the bacterial community in a soil-microbe-plant system and identified the main bacterial responders. Antibiotic effects on the soil microbiome depended on antibiotic type and exposure time. TC resulted in an acute but more rapidly declining effect on soil microbiome while CIP and SMM led to a delayed antibiotic effect. The soil exposed to AM presented a highly similar bacterial structure to that exposed to TC rather than to SMM and CIP. TC, SMM and CIP had their own predominantly impacted taxonomic groups that include both resistance and sensitive bacteria. The antibiotic sensitive responders predominantly distributed within the phylum Proteobacteria. The potential bacteria resistant to each antibiotic exhibited phyla preference to some extent, particularly those resistant to TC. CIP and SMM resistance in soil was increased with exposure time while TC resistance gave the opposite result. Overall, the work extended the understanding of antibiotic effects on soil microbiome after introduced into the soil during greenhouse vegetable cultivation.

[Interaction Between Sulfonamide Antibiotics Fates and Chicken Manure Composting].

Based on aerobic manure composting with or without the addition of a mixture of sulfadimethoxine SM2 and sulfamonomethoxine SMM (1:1, m/m), changes in the physic-chemical properties of manure compost, the microbial community physiological profiles, the antibiotics concentration and the abundances of five antibiotic resistance genes (ARGs) during the composting were tracked. The results indicated that the introduction of sulfonamide antibiotics led to inhibition on the basal respiration of manure compost during the early composting period, delayed the formation of thermophilic temperature and reduced the conversion of nutrients such as organic matter, ammonia nitrogen and nitrate nitrogen. Meanwhile, the introduction of sulfonamide antibiotics dramatically affected the physiological profile of microbial community in manure in the middle stage of composting. HPLC-MS/MS results showed that both SMM and SM2 in manure were completely degraded within 14 days, while the degradation rate of SMM was faster than that of SM2. For both composting treatments with or without addition of exogenous antibiotics, the relative abundance of sull and sul2 showed an initial decline in the first 14 or 21 days and a slight increase thereafter. The addition of exogenous antibiotics showed insignificant enhancement on increasing the relative abundance of sul1 and IntI1 in manure, but resulted in an apparent increase in sul2 relative abundance. Although the fates of tetQ and tetW during composting were different from that of sulfonamide ARGs, the introduction of sulfonamide antibiotics into manure increased the relative abundance of tetracycline ARGs. Redundancy analysis indicated that composting temperature correlated negatively with sul1, sul2 and IntI1 relative abundance in manure but had no obvious relationship with tetQ and tetW relative abundance. All the ARGs detected in this work correlated negatively with C/N ratio and the nitrate nitrogen concentration of manure compost but positively correlated with pH, moisture and ammonia nitrogen concentration of manure compost.

Variations in the fate and biological effects of sulfamethoxazole, norfloxacin and doxycycline in different vegetable-soil systems following manure application.

The fate of sulfamethoxazole (SMZ), norfloxacin (NOR) and doxycycline (DOX) and their biological effects in radish and pakchoi culture systems were investigated. DOX dissipated more rapidly than SMZ and NOR, while radish and pakchoi cultivation increased the removal of residual DOX in soils. Dissipation of NOR was accelerated in radish soils but was slowed down slightly in pakchoi soils. Vegetable cultivation exerted an insignificant effect on SMZ removal. Investigation of antibiotic bioaccumulation showed that the uptake of DOX by radish and pakchoi was undetectable, but the radish accumulated more SMZ and NOR than pakchoi. Among the three antibiotics, only SMZ use exhibited an apparent suspension of plant seed germination, up-ground plant growth and soil microbial diversity. Pakchoi responded more sensitively to SMZ than did the radish. Principal component analysis (PCA) based on MicroRESP™ indicated that the sampling time and antibiotic treatments could influence the soil microbial community. Only in the pakchoi soils did antibiotic application exert a more robust effect on the microbial community than the sampling time; SMZ treatments and DOX treatments could be clearly discriminated from the control treatments. These results are crucial for an assessment of the potential risks of antibiotics to culture system practices and suggest that good agricultural practices help to limit or even reduce antibiotic pollution.

Effects of manure and mineral fertilization strategies on soil antibiotic resistance gene levels and microbial community in a paddy-upland rotation system.

This work investigated the responses of antibiotic resistance genes (ARGs) and the soil microbial community in a paddy-upland rotation system to mineral fertilizer (NPK) and different application dosages of manure combined with NPK. The occurrence of five tetracycline ARGs (tetA, tetB, tetC, tetG and tetW), two sulfonamide ARGs (sul1 and sul2) and one genetic element (IntI1) was quantified. NPK application showed only slight or no impact on soil ARGs abundances compared with the control without fertilizer. Soil ARGs abundances could be increased by manure-NPK application but was related to manure dosage (2250-9000 kg ha(-1)). Principal component analysis (PCA) showed that the soil ARG profile of the treatment with 9000 kg ha(-1) manure separated clearly from the other treatments; the ARGs that contributed most to the discrimination of this treatment were tetA, tetG, tetW, sul1, sul2 and IntI1. Community level physiological profile (CLPP) analysis showed that increasing manure dosage from 4500 kg ha(-1) to 9000 kg ha(-1) induced a sharp increase in almost all of the detected ARGs but would not change the microbial community at large. However, 9000 kg ha(-1) manure application produced a decline in soil microbial activity. Determination of antibiotics and heavy metals in soils suggested that the observed bloom of soil ARGs might associate closely with the accumulation of copper and zinc in soil.

Effects of combined application of organic and inorganic fertilizers plus nitrification inhibitor DMPP on nitrogen runoff loss in vegetable soils.

The application of nitrogen fertilizers leads to various ecological problems such as large amounts of nitrogen runoff loss causing water body eutrophication. The proposal that nitrification inhibitors could be used as nitrogen runoff loss retardants has been suggested in many countries. In this study, simulated artificial rainfall was used to illustrate the effect of the nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen loss from vegetable fields under combined organic and inorganic nitrogen fertilizer application. The results showed that during the three-time simulated artificial rainfall period, the ammonium nitrogen content in the surface runoff water collected from the DMPP application treatment increased by 1.05, 1.13, and 1.10 times compared to regular organic and inorganic combined fertilization treatment, respectively. In the organic and inorganic combined fertilization with DMPP addition treatment, the nitrate nitrogen content decreased by 38.8, 43.0, and 30.1% in the three simulated artificial rainfall runoff water, respectively. Besides, the nitrite nitrogen content decreased by 95.4, 96.7, and 94.1% in the three-time simulated artificial rainfall runoff water, respectively. A robust decline in the nitrate and nitrite nitrogen surface runoff loss could be observed in the treatments after the DMPP addition. The nitrite nitrogen in DMPP addition treatment exhibited a significant low level, which is near to the no fertilizer application treatment. Compared to only organic and inorganic combined fertilizer treatment, the total inorganic nitrogen runoff loss declined by 22.0 to 45.3% in the organic and inorganic combined fertilizers with DMPP addition treatment. Therefore, DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation in agriculture and decline the nitrogen runoff loss, minimizing the nitrogen transformation risk to the water body and being beneficial for the ecological environment.

Soil microbial systems respond differentially to tetracycline, sulfamonomethoxine, and ciprofloxacin entering soil under pot experimental conditions alone and in combination.

This study investigated soil microbial responses to the application of tetracycline (TC), sulfamonomethoxine (SMM), and ciprofloxacin (CIP) alone and in combination in a soil culture pot experiment conducted at Hangzhou, China. Multiple approaches were applied for a better and complete depiction. Among the three antibiotics, SMM has a lowest dissipation and shows a most dramatic inhibition on microbial community and metabolism diversity. The combined application (AM) of SMM, CIP, and TC improved the dissipation of each antibiotic; similarly, SMM- and CIP-resistant bacteria showed larger populations in the AM than all single applications. Soils accumulated a large content of NO3-N at day 20 after multi-antibiotics perturbation. All antibiotics stimulated soil basal respirations and inhibited soil metabolism diversity, whereas the interruption exerted by SMM and AM lasted for a longer time. Six nitrogen-cycling genes including chiA, amoA, nifH, nirK, nirS, and narG were quantified and found to decrease owing to both single- and multi-antibiotics perturbation. Overall, AM was most interruptive for soils, followed by SMM perturbation, while other antibiotics could be less interruptive. These results provide systematic insights into how soil microbial systems would shift under each single- or multi-antibiotics perturbation.

Engineering Aspergillus oryzae A-4 through the chromosomal insertion of foreign cellulase expression cassette to improve conversion of cellulosic biomass into lipids.

A genetic modification scheme was designed for Aspergillus oryzae A-4, a natural cellulosic lipids producer, to enhance its lipid production from biomass by putting the spotlight on improving cellulase secretion. Four cellulase genes were separately expressed in A-4 under the control of hlyA promoter, with the help of the successful development of a chromosomal genetic manipulation system. Comparison of cellulase activities of PCR-positive transformants showed that these transformants integrated with celA gene and with celC gene had significantly (p<0.05) higher average FPAase activities than those strains integrated with celB gene and with celD gene. Through the assessment of cellulosic lipids accumulating abilities, celA transformant A2-2 and celC transformant D1-B1 were isolated as promising candidates, which could yield 101%-133% and 35.22%-59.57% higher amount of lipids than the reference strain A-4 (WT) under submerged (SmF) conditions and solid-state (SSF) conditions, respectively. Variability in metabolism associated to the introduction of cellulase gene in A2-2 and D1-B1 was subsequently investigated. It was noted that cellulase expression repressed biomass formation but enhanced lipid accumulation; whereas the inhibitory effect on cell growth would be shielded during cellulosic lipids production owing to the essential role of cellulase in substrate utilization. Different metabolic profiles also existed between A2-2 and D1-B1, which could be attributed to not only different transgene but also biological impacts of different integration. Overall, both simultaneous saccharification and lipid accumulation were enhanced in A2-2 and D1-B1, resulting in efficient conversion of cellulose into lipids. A regulation of cellulase secretion in natural cellulosic lipids producers could be a possible strategy to enhance its lipid production from lignocellulosic biomass.

[Distribution characteristics of aggregates organic carbon in a paddy soil chronosequence].

By the method of physical fractionation of organic matter, this paper studied the distribution characteristics of organic carbon in different particle size aggregates in a paddy soil chronosequence on the south bank of Hangzhou Bay, East China. In the plow layers of the paddy soil chronosequence, micro-aggregates (<0. 25 mm) dominated, and the proportion of large micro-aggregates (0.053-0.25 mm) decreased with increasing rice cultivation year. In the micro-aggregates (<0. 053 mm and 0. 053-0. 25 mm), the organic carbon content increased with increasing rice cultivation time; and in the aggregates (0. 053-2 mm), the ratio of the organic carbon in different particle size fractions to the bulk soil organic carbon increased with decreasing particle size, and the organic carbon mainly distributed in large micro-aggregates (0. 053 -0. 25 mm). With increasing rice cultivation time, soil particulate organic carbon decreased, indicating that the paddy soil with a longer rice cultivation history had a stronger capability of carbon sequestration than the soil with a shorter rice cultivation history, and the early cultivated paddy soil still had great potential for carbon sequestration.

[Effect of DMPP on inorganic nitrogen runoff loss from vegetable soil].

The effect of urea with 1% 3,4-dimethyl pyrazole phosphate (DMPP) on inorganic nitrogen runoff loss from agriculture field was determined in an undisturbed vegetable soil by using the simulated artificial rainfall method. The results show that, during the three simulated artificial rainfall period, the ammonium nitrogen content in the runoff water is increased 1.42, 2.82 and 1.95 times with the DMPP application treatment compared to regular urea treatment, respectively. In the urea with DMPP addition treatment, the nitrate nitrogen content is decreased 70.2%, 59.7% and 52.1% in the three simulated artificial rainfall runoff water, respectively. The nitrite nitrogen content is also decreased 98.7%, 90.6% and 85.6% in the three simulated artificial rainfall runoff water, respectively. The nitrate nitrogen and nitrite nitrogen runoff loss are greatly declined with the DMPP addition in the urea. Especially the nitrite nitrogen is in a significant low level and is near to the treatment with no fertilizer application. The inorganic nitrogen runoff loss is declined by 39.0% to 44.8% in the urea with DMPP addition treatment. So DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation, decline the nitrogen runoff loss, lower the nitrogen transformation risk to the waterbody and be beneficial for the ecological environment.

[Study on the drug-resistant genes associated with beta-lactams and aminoglycosides in clinically isolated Pseudomonas aeruginosa].

OBJECTIVE: To investigate drug-resistant genes associated with beta-lactams and aminoglycosides in clinically isolated Pseudomonas aeruginosa. METHODS: Twenty strains of Pseudomonas aeruginosa were isolated from wound excretion of hospitalized burn patients. The strains resistant to 14 antibiotics were selected for detection of 16 kind of drug-resistant genes (TEM, SHV, OXA-10 cluster, PER, VEB, GES, CARB, CTX-M- I, IMP, VIM, SPM, GIM, DHA, MOX, FOX, oprD2) and 6 kind of aminoglycoside modification genes (aac(3)- I, aac(3)-II, aac(6')-I, aac(6')-II, ant (3")- I , ant(2")- I) in them by PCR. RESULTS: Among the 20 strains resistant to beta-lactam , all of them were TEM and GES positive (100%), oprD2 gene depletion in 5 strains (25%). All other genes were negative. Among aminoglycoside resistant genes, 20 strains were aac (6') - I positive (100%), 7 were ant (2") - I positive (35%), and negative for other stains. CONCLUSION: There were very high existence rates of TEM, GES and aac (6')- I genes in Pseudomonas aeruginosa isolated from clinical burn patients. The fact that GES-5 gene has also been detected in Pseudomonas aeruginosa, suggesting this organism is highly drug resistant in our burn unit.