[Bacterial Community Structure of Typical Lake Sediments in Yinchuan City and Its Response to Heavy Metals]

Lake wetlands are extremely important and special ecosystems, which are important for regional water resource storage, environmental protection, and biodiversity maintenance. Sediment bacteria are an important component of lake ecosystems and are a major driver of biogeochemical cycling in lakes. In order to investigate the community structure of bacteria in typical lake sediments in Yinchuan City and their influencing factors, three typical lakes in Yinchuan City (Yuehai Lake, Mingcui Lake, and Xiniu Lake) were selected for the study and surface sediments were collected in January, April, July, and October 2021. The composition of the sediment bacterial community was examined using 16S rDNA high-throughput sequencing technology, and the response relationships between them and heavy metals were explored. The results showed that the ecological hazard coefficient for heavy metals in the sediments of three typical lakes in Yinchuan City was far less than 40, and the ecological hazard index was far less than 150, all of which indicated a minor ecological hazard. There were no significant differences in bacterial community diversity among the three lakes, but there were significant variations in diversity among the lakes in different seasons and significant differences in community composition. The dominant phyla (top three in terms of relative abundance) in Yuehai Lake, Mingcui Lake, and Xiniu Lake were Proteobacteria, Bacteroidetes, and Chloroflexi. The dominant lower orders were Gammaproteobacteria, Alphaproteobacteria, and Deltaproteobacteria. The main divergent species that occurred at the phylum level in typical lakes in Yinchuan were Proteobacteria, Bacteroidetes, Euryarchaeota, Firmicutes, Actinobacteria, and Acidobacteria. The sediment bacterial community structure of Yuehai Lake was significantly correlated with Cu, Fe, Mn, Zn, As, and Pb; the sediment bacterial community structure of Lake Mingcui was significantly correlated with Fe, Pb, and Cr; and the sediment bacterial community structure of Xiniu Lake was not significantly correlated with heavy metals. The types and contents of sediment heavy metals had a significant effect on the bacterial community structure of sediments in Yinchuan Yuehai Lake and Mingcui Lake and were important environmental factors that caused changes in the bacterial community structure of lake sediments.

A Preliminary Study of Bacterioplankton Community Structure in the Taiyangshan Wetland in Ningxia and Its Driving Factors

The Taiyangshan Wetland, a valuable wetland resource in the arid zone of central Ningxia, is critical for flood storage and drought resistance, climate regulation, and biodiversity protection. Nevertheless, the community structure and diversity of bacterioplankton in the Taiyangshan Wetland remains unclear. High-throughput sequencing was used to analyze the differences in bacterioplankton structure and major determinants in the Taiyangshan Wetland from April to October 2020. The composition and diversity of the bacterioplankton community varied significantly in different sampling periods but showed negligible differences across lake regions. Meanwhile, the relative abundances of bacterioplankton Bacteroidetes, Actinobacteria, Firmicutes, Chloroflexi, Tenericutes, Epsilonbacteraeota, and Patescibacteria were significantly different in different sampling periods, while the relative abundances of Cyanobacteria in different lake regions were quite different. Network analysis revealed that the topological attributes of co-occurrence pattern networks of bacterioplankton were high, and bacterioplankton community compositions were complicated in the month of July. A mantel test revealed that the bacterioplankton community in the entire wetland was affected by water temperature, electrical conductivity, dissolved oxygen, salinity, total nitrogen, ammonia nitrogen, chemical oxygen demand, fluoride, and sulfate. The bacterioplankton community structure was affected by ten environmental parameters (e.g., water temperature, dissolved oxygen, salinity, and permanganate index) in April, while the bacterioplankton community was only related to 1~2 environmental parameters in July and October. The bacterioplankton community structure in Lake Region IV was related to seven environmental parameters, including dissolved oxygen, pH, total nitrogen, and chemical oxygen demand, whereas the bacterioplankton community structures in the other three lake regions were related to two environmental parameters. This study facilitates the understanding of the bacterioplankton community in wetlands in arid areas and provides references to the evaluation of aquatic ecological management of the Taiyangshan Wetland.

Notch ligand Delta-like 1 promotes the metastasis of melanoma by enhancing tumor adhesion

Notch signaling plays a vital role in tumorigenicity and tumor progression by regulating proliferation, invasion, and the tumor microenvironment. Previous research by our group indicated that Notch ligand Delta-like 1 (Dll1) is involved in angiogenesis in melanoma, and we noticed that it took a longer time to trypsinize Dll1-expressing B16 melanoma cells than the control cells. In this article, we extended our study to investigate the effects of Dll1 on tumor cell adhesion and metastasis. Dll1 overexpression activated Notch signaling in B16 tumor cells and significantly enhanced the adhering capacity of B16 tumor cells both in vitro and in vivo. B16-Dll1 cells also had a higher metastatic potential than their counterpart in the mouse model of lung metastasis. Along with increased Dll1 expression, N-cadherin, but not E-cadherin, was upregulated in B16-Dll1 cells. These data suggested that Notch ligand Dll1 may enhance the adhesion and metastasis of melanoma cells by upregulation of N-cadherin.

[Studies on relationship of phytoplankton and water environmental factors in Shahu Lake]

Analysis approaches of correlation, multiple stepwise regression and canonical correspondence analysis were employed between phytoplankton and water environmental factors in ShaHu Lake based on the data from Apr. 2009 to Jan. 2010. The results showed that the correlation between phytoplankton density, phytoplankton biomass, chlorophyll-a and water temperature (WT), total nitrogen (TN), total phosphorus (TP), potassium permanganate index,5 days biochemical oxygen demand (BOD5) was positive, and phytoplankton density, phytoplankton biomass, chlorophyll-a and Secchi-depth (SD) was negatively correlated. Followed by the importance of environmental factors which affected phytoplankton density in Shahu Lake ranged as follows: WT, potassium permanganate index, SD, BOD5, TP, TN. Those affected phytoplankton biomass ranged as follows: WT,TP, potassium permanganate index,SD,TN. Those affected on chlorophyll-a ranged as follows: potassium permanganate index, WT, SD, TP, TN, BOD5. CCA result showed that 16 species of phytoplankton were divided into 3 groups which had the obvious seasonal distribution characteristics in Shahu Lake. SD, potassium permanganate index,WT, TN, TP were the main water environmental factors correlated with the distribution of phytoplankton community of Shahu Lake.

[Influence of intracerebroventricular injection of sodium nitroprusside L-arginine and NG-nitro-L-arginine on cardiovascular activity in conscious rats]

In order to study the cardiovascular effect of NO in conscious rats, sodium nitroprusside (SNP), the precursor of NO (L-Arginine, Arg-Arg) and one of the inhibitor of NOS (NG-nitro-L-arginine, NNLA) were intracerebroventricularly (icv) injected. Our experimental results indicated that, an apparent dose-dependent hypertensive effect was produced by icv administration of SNP (8, 16, 32 and 32 micrograms), a tachycardiac effect was also produced at the same time. In addition, hypertension and tachycardia were produced by icv L-arginine and the dipeptide Arg-Arg. Furthermore a hypotensive and bradycardiac effect can be produced by icv NNLA. These results suggest that there is a positive effect on cardiovascular activity due to increase of endogeneuse NO in the rat brain and a negative effect on cardiovascular activity due to decrease of endogeneuse NO in the rat brain.

[The effect of melatonin on enhancing immune function and inhibiting the ability of NO over-release in morphine dependent mice]

AIM

To observe the effects and mechanism of melatonin (MT) on the immune function of morphine dependent mice.

METHODS

A physical dependent mice model was established by repeated subcutaneous injection of morphine. The intensity of morphine withdrawal syndrome was evaluated according to the weight of immune organs, the proliferation reaction of stimulated splenic lymphocytes by Con A, the phagoindex of blood primed macrophages and the content of NO induced in the peritoneal macrophage (pM phi).

RESULTS

MT reversed the inhibitory effect of morphine on the proliferation ability of splenic lymphocytes and enhanced the phagocytosis of macrophages of morphine dependent mice obviously and prevented the over-release of NO from pM phi. The enhancing effects of MT on the phagocytosis can be prevented by naloxon.

CONCLUSION

MT can significantly enhance the immune function of morphine dependent mice and inhibit NO excessive release from pM phi.

[The depressor effect of intracerebroventricular injection of BQ123 and endothelin (ET)--antiserum on hypertensive rats produced by aorta stenosis and hypersaline uptake]

An experimental model of hypertensive rat was made by abdominal aorta stenosis and hypersaline uptake. The blood pressure was significantly decreased by intracerebroventricular injection (i.c.v.) of BQ123 a potent antagonist of ET-1 receptor, in a dose-dependent manner. Negative chronotropic effect on the heart was produced by high dose of BQ123, while the depressor effect was produced by i.c.v. ET-antiserum. These results indicate that endothelin in CNS may play an important role in the pathological physiology of hypertension.

[The characterization of 5-HT1A receptor in the central nervous system of the spontaneously hypertensive rats]

With method of the radio binding assay (RBA), it was observed that in the present work that in normotensive Wistar rats, the specific binding of [3H] 8-OH-DPAT at 2.4 nmol/L concentration was about the same in hippocampus (7.62 +/- 0.24 pmol/mg), hypothalamus (8.18 +/- 0.63 pmol/mg) and lower brain stem (9.11 +/- 0.78 pmol/mg); whereas, in spontaneously hypertensive rats (SHR), these regional specific bindings were 2(+)-3+ times higher. Scatchard analyses showed that the Bmax was also higher than that of normotensive Wistar rats in hippocampus and hypothalamus, whereas the KD in hypothalamus was lower. The differences between SHR and normotensive rats in the 5-HT1A receptor contents in various brain regions appear to be related to one of the linking events in the generation of hypertension.

Serotonin receptor subtypes in spinal antinociception in the rat

The aim of the present study was to clarify the subtypes of serotonin (5-HT) receptors involved in spinal antinociception in the rat. 1) Intrathecal (i.t.) injection of 5-HT (25-200 micrograms) produced a dose-dependent increase in tail-flick latency. 2) Intrathecal injection of fluoxetine, a 5-HT uptake blocker (25-40 micrograms), resulted in a bell-shaped dose-related antinociception with peak effects occurring at 10 micrograms. 3) A bell-shaped antinociceptive effect was obtained by i.t. injection of the 5-HT1A agonist (+)-hydroxy-2-(di-N-propylamino)tetralin (0.25-2 micrograms), with the maximal effect occurring at 0.5 micrograms, which can be prevented by the 5-HT1A antagonist spiperone (25 micrograms i.t.). 4) A similar dose-response curve was obtained following the i.t. injection of the 5-HT1B agonist 1-[3-(trifluoromethyl)phenyl]-piperazine maleate (1-125 micrograms) with the maximal effect observed at 25 micrograms. 5) Neither the 5-HT2 agonist (+/-)-alpha-methyl-5-HT-maleate nor the 5-HT3 agonist (+/-)-2-methyl-5-HT-maleate produced significant antinociceptive effects at doses up to 50 micrograms. Spontaneous tail-flicks emerged at doses higher than 50 micrograms. 6) The antinociceptive effect induced by 5-HT (200 micrograms i.t.) could be attenuated dose-dependently either by the 5-HT1A antagonist spiperone (5 and 25 micrograms i.t.) or by the 5-HT1C/2 antagonist mianserin (0.5-50 micrograms i.t.), but not by the 5-HT2 antagonist 1-(1-naphthyl)piperazine hydrochloride or the 5-HT3 antagonist 3-tropanyl-indole-3-carboxylate.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of different thyroid states on 5-HT1A receptor in adult rat brain]

The effects of dysthyroidism on central 5-HT1A receptor subtype in adult Wistar rats were investigated. Hyperthyroidism and hypothyroidism were respectively produced with the administration of T3 and propylthiouracil (PTU) via gavage for 2 weeks. Heart rate, oxygen consumption, anal temperature and plasma T3 concentration were increased in hyperthyroid rats and decreased in hypothyroid rats significantly. Radioligand binding assay showed that the specific binding of [3H] 8-hydroxy-2-(di-n-propylamino) tetralin ([3H] 8-OH-DPAT) at 0.6 nmol/L concentration was highest in hippocampus, next in cerebral cortex, and lowest in hypothalamus, brain stem and corpus striatum in euthyroid rats. Hyperthyroidism increased the binding significantly in hippocampus but decreased in cortex. No change was found in the other brain regions. Scatchard analyses revealed that the Bmax was increased in hippocampus and decreased in cortex, whereas the KD was not consistently affected in hyperthyroid rats in comparison with that in euthyroid rats. However, there were no significant changes mentioned above in all these brain regions of hypothyroid rats. Our results indicate that there seems to exist an imbalance of the serotonergic activity mediated via 5-HT1A receptor between hippocampus and cerebral cortex in hyperthyroids. This might be one of the mechanisms leading to psychoneural disorders in hyperthyroidism.

[Cardiovascular reactions mediated by 5-HT1A and 5-HT3 receptors in the spinal cord of conscious rats]

Intrathecal administration (ith) of 5-hydroxytryptamine (5-HT, 1.56, 3.125, 6.25 and 12.5 micrograms/10 microliters) to conscious rats produced a marked dose-dependent hypertensive effect without significant change in heart rate (HR). Ith administration of fluoxetine (10 micrograms/microliters), one of the presynaptic reuptake inhibitors of 5-HT, produced a marked increase in the mean arterial blood pressure (mABP). This effect could be prevented by a pretreatment with cinanserin (25 micrograms ith) as a blocker of 5-HT receptor. It was further observed that ith of 8-OH-DAPT (2.5, 5, 10 micrograms/10 microliters), a 5-HT1A receptor agonist, produced a dose-dependent increase of mABP and lowering of HR. However, ith of 5-HT3 receptor agonist 2-Methylserotonin (25, 50, 100 micrograms/10 microliters), decreased mABP markedly without change in HR. The results indicate that 5-HT in the spinal cord may extra hypertensive effect via 5-HT1A receptor and a hypotensive effect via 5-HT3 receptor. This gives a possible explanation about the conflicting reports concerning the effect of 5-HT in the central nervous system on blood pressure.

A multisectoral approach to primary health care in Fujian, China

The government of Yongan in Fujian province has developed a multisectoral primary health care program in the rural community of Dahu with the aim of reaching "Health for All" by 1993. In keeping with the spirit of the Alma Ata declaration and the tradition of local self-reliance in China, the program has involved the entire community and is financed almost exclusively at the local level. Community leaders were trained in the importance of primary health care so that they could serve as role models. The project includes school health education, domestic hygiene education, reconstruction of homes to separate the kitchen, toilet and animals pens, road construction to eliminate dust, environmental sanitation, occupational health, and the upgrading of health care facilities. A number of local ordinances regarding construction, zoning and smoking have also been instituted. The results of the project's first year of implementation in two villages indicate that construction of the new road is near completion, and access to clean water is almost universal. Gains are also reported in the percentage of the population receiving physical examinations, the number of health stations that now meet state standards, and the number of homes that are constructed according to the new guidelines.

Central neurotransmitters and acupuncture analgesia

The role played by central neurotransmitters in acupuncture analgesia was evaluated by correlating neurochemical changes in central nervous system with the acupuncture effect, as well as modification of the acupuncture effects by pharmacological manipulations of central neurotransmitters. The results of experimental studies which were performed mainly on rats and rabbits indicated that central serotonin and endogenous opiate-like substances (OLS) seem to be the most important substrates for mediation of acupuncture analgesia while central catecholamines, especially norepinephrine through alpha receptors, may exert an antagonistic effect. It was also found that prolonged and repeated acupuncture resulted in a gradual decrease of the acupuncture effects. The development of some endogenous anti-opiate substrates (AOS) in central nervous system was tentatively implicated.