Seasonal variations of macrozoobenthic community trophic structure in the waters adjacent to the seaweed beds of Dalian Island in the North Yellow Sea.

To investigate the effects of algal detritus export on the trophic structure of macrozoobenthic community in the adjacent benthic habitat during the bloom and decline of macroalgae, we collected macrozoobenthos from the adjacent sea area of Dalian Island in the North Yellow Sea in May (the algal bloom period) and August (the algal decay period) of 2020. We quantifyied the seasonal changes in the trophic structure of macrozoobenthic community by using carbon and nitrogen stable isotope techniques. Results showed that δ13C and δ15N values of macrozoo-benthos in May ranged from -23.14‰ to -14.24‰, 6.21‰ to 12.90‰, respectively, and -22.36‰ to -14.13‰, 5.33‰ to 12.00‰, respectively in August. Results of PERMANOVA analysis showed that δ13C values of macrozoobenthos differed significantly between the two months, while δ15N values were not significantly different. Based on the Euclidean distance, the macrozoobenthic communities in both months could be classified into five trophic functional groups. The trophic levels of macrozoobenthos ranged from 2.00 (Nitidotellina minuta) to 3.97 (Glycera onomichiensis) in May and from 2.00 (N. minuta) to 3.96 (G. onomichiensis) in August. The δ13C range, δ15N range, mean centroid distance, total area and corrected standard ellipse areas which represented community trophic structure indices in August were higher than those in May. Our results indicated that the trophic diversity level and trophic niche width of the macrozoobenthic community in the adjacent sea area of the seaweed bed were higher in the algal decline season.

[Trophic structure of pelagic fishery organism assemblage in the central and western South China Sea in spring revealed by carbon and nitrogen stable isotope analysis]. / åŸºäºŽç¢³æ°®ç¨³å®šåŒä½ç´ çš„å—æµ·ä¸­è¥¿éƒ¨æµ·åŸŸæ˜¥å­£ä¸­ä¸Šå±‚æ¸”ä¸šç”Ÿç‰©ç¾¤è½è¥å »ç»“æž„.

Carbon and nitrogen stable isotope analysis was carried out on pelagic fishery organisms caught in light traps and falling nets in the central and western South China Sea in the spring of 2018. The stable isotope values of the sampled individuals were used to elucidate the isotopic variations for the pelagic fishery organisms, to classify species into trophic functional groups, and to compare the differences of trophic structure among the classified trophic functional groups. The results showed that among 23 fishery species the mean δ13C value of Coryphaena hippurus was the lowest (-17.58‰±0.21‰), and that of Grammistes sexlineatus was the highest (-19.86‰±0.33‰). The mean δ15N values ranged from 8.31‰ in Psenes cyanophrys to (12.46±0.74)‰ in Chirocentrus dorab. The continuous trophic spectrum indicated that the trophic level (TL) for the sampled pela-gic fishery organisms ranged from 3.01 to 4.23, of which 19 species (83% of the total) fell between TL 3.0 and 4.0. The 23 species of fishery organisms were classified into three trophic functional groups, i.e., plankton feeding functional group (PFFG), nekton feeding functional group (NFFG), and mixed feeding functional group (MFFG). The analysis of standard ellipse area (SEA) showed that the PFFG occupied the largest trophic niche width (SEA=1.56‰2), followed by the MFFG (SEA=0.99‰2) and NFFG (SEA=0.31‰2). The MFFG overlapped with PFFG and NFFG in the trophic niche, with a relative percentage of 17% and 26%, respectively. There was no overlap between PFFG and NFFG.

Prenatal and Early Postnatal Exposure to Cigarette Smoke Decreases BDNF/TrkB Signaling and Increases Abnormal Behaviors Later in Life.

BACKGROUND: Cigarette smoke exposure during prenatal and early postnatal periods increases the incidence of a variety of abnormal behaviors later in life. The purpose of this study was to identify the possible critical period of susceptibility to cigarette smoke exposure and evaluate the possibe effects of cigarette smoke during early life on brain-derived neurotrophic factor/neurotrophic tyrosine kinase receptor B signaling in the brain. METHODS: Three different age of imprinting control region mice were exposed to cigarette smoke or filtered air for 10 consecutive days beginning on either gestational day 7 by maternal exposure, or postnatal days 2 or 21 by direct inhalation. A series of behavioral profiles and neurotrophins in brain were measured 24 hours after mice received acute restraint stress for 1 hour on postnatal day 59. RESULTS: Cigarette smoke exposure in gestational day 7 and postnatal day 2 produced depression-like behaviors as evidenced by significantly increased immobility in both tail suspension and forced-swim test. Increased entry latencies, but not ambulation in the open field test, were also observed in the gestational day 7 and postnatal day 2 cigarette smoke exposure groups. Genetic analysis showed that gestational day 7 cigarette smoke exposure significantly altered mRNA level of brain-derived neurotrophic factor/tyrosine kinase receptor B in the hippocampus. However, behavioral profiles and brain-derived neurotrophic factor/tyrosine kinase receptor B signaling were not significantly changed in PND21 cigarette smoke exposure group compared with FA group. CONCLUSIONS: These results suggest that a critical period of susceptibility to cigarette smoke exposure exists in the prenatal and early postnatal period, which results a downregulation in brain-derived neurotrophic factor/tyrosine kinase receptor B signaling in the hippocampus and enhances depression-like behaviors later in life.

Substance p regulates environmental tobacco smoke-enhanced tracheal smooth muscle responsiveness in mice.

Environmental tobacco smoke (ETS) is an environmental trigger that leads to airway inflammation and airway hyperresponsiveness (AHR) in susceptible individuals and animals, but the underlying mechanism is not fully understood. Substance P (SP) release from sensory nerve fibers has been linked to AHR. The present experiments characterize the role of SP in tracheal smooth muscle on ETS-increased airway responses. The mice were exposed to either sidestream tobacco smoke (SS), a surrogate to ETS, or filtered air (FA) for 1 day or 5 consecutive days. Contractions of tracheal smooth muscle to SP and electrical field stimulation (EFS) were not significantly altered in 1 of day SS-exposed mice. However, 5 of days SS exposure significantly increased airway smooth muscle contractions to SP and EFS. Administration of CP-99994, an antagonist of the neurokinin (NK)1 receptor, attenuates the SS exposure-enhanced tracheal smooth muscle responses to EFS. Furthermore, the immunohistochemistry showed that SP nerve fibers were increased in tracheal smooth muscle after 5 of days SS exposure. These results suggest that the increased SP production may contribute to SS-enhanced smooth muscle responsiveness in mice trachea.

[Structure and function of Lidao artificial reef ecosystem in Rongcheng of Shandong Province, East China: an evaluation based on Ecopath model].

Based on the annual investigation data of biological resources in Lidao artificial reef zone in 2009, an Ecopath model of the Lidao artificial reef ecosystem was constructed to analyze the energy flow pattern and the system attributes of the ecosystem. The model was consisted of 19 functional groups, basically covering the main processes of the energy flow in the Lidao artificial reef ecosystem. The functional groups were divided according to the relationships of the corresponding positions between appeared fishes and artificial reefs, and the planktonic heterotrophic bacteria were included into the model as a functional group. The fishes appeared in the investigation zone were divided into seven functional groups, and the trophic levels of the functional groups varied from 1.00 to 3.72. The type I fishes had the highest trophic level. The total system throughput was estimated to be 10786.68 t x km(-2) x a(-1), 27% of which flowed to detritus, and 17% flowed out the ecosystem in the forms of fishing and sediment. The total net primary productivity of the system was 4131.97 t x km(-2) x a(-1) and the total energy transfer efficiency was 10.5%. The proportion of the total flow originated from detritus was 39%, and that from primary producers was 61%, indicating that the energy flow was dominated by food web rather than detritus. The ratio of total primary productivity to total respiration of the system was 1.84, the connectivity index was 0.20, and the Finn's cycling index and the mean path length of the energy flow were 4.5% and 2.62, respectively. This study showed that the Lidao artificial reef ecosystem had a relatively low maturity and stability, was at a developing stage, and had weak resistance against outside interference. The ecological environment and the output of fisheries in the artificial reef zone would have inter-annual fluctuations, and thus, the eco-environment restoration of the artificial reef ecosystem could only be realized by the sustainable maintaining of the ecosystem.

Prenatal and early, but not late, postnatal exposure of mice to sidestream tobacco smoke increases airway hyperresponsiveness later in life.

BACKGROUND: Cigarette smoke exposure in utero and during early postnatal development increases the incidence of asthma and airway hyperresponsiveness (AHR) later in life, suggesting that a possible critical period of developmental sensitivity exists in the prenatal and early postnatal periods. OBJECTIVE: We investigated mechanisms of susceptibility during critical developmental periods to sidestream smoke (SS) exposure and evaluated the possible effects of SS on neural responses. METHODS: We exposed three different age groups of mice to either SS or filtered air (FA) for 10 consecutive days beginning on gestation day (GD) 7 by maternal exposure or beginning on postnatal day (PND) 2 or PND21 by direct inhalation. Lung function, airway substance P (SP) innervation, and nerve growth factor (NGF) levels in broncho alveolar lavage fluid were measured after a single SS exposure on PND59. RESULTS: Methacholine (MCh) dose response for lung resistance (R(L)) was significantly elevated, and dynamic pulmonary compliance (C(dyn)) was significantly decreased, in the GD7 and PND2 SS exposure groups compared with the FA groups after SS exposure on PND59. At the same time points, the percent area of SP nerve fibers in tracheal smooth muscle and the levels of NGF were significantly elevated. MCh dose-response curves for R(L) and C(dyn), SP nerve fiber density, and the level of NGF were not significantly changed in the PND21 exposure group after SS exposure on PND59. CONCLUSIONS: These results suggest that a critical period of susceptibility to SS exposure exists in the prenatal and early postnatal period of development in mice that results in increased SP innervation, increased NGF levels in the airway, and enhanced MCh AHR later in life.

[Experimental study progress on tribendimidine, artemether and artesunate against Clonorchis sinensis and other trematodes].

Currently praziquantel is one of the major drugs used in treatment of schistosomiasis and other trematode infections. Recent experimental studies indicate that a new anthelmintic, tribendimidine, is used in the treatment of intestinal nematodes, also possesses effect against several species of trematodes including Clonorchis sinensis, Opisthorchis viverrini and Echinostoma caproni. Tribendimidine is even more effective against C. sinensis in rats that a single 300 mg/kg oral dose cures almost all of the animals treated, a lower cure dose than praziquantel (375-500 mg/kg). The anti-malarial drugs artemether and artesunate are not only effective in the prevention of schistosomiasis, but also effective against several species of trematodes, especially C. sinensis. The single oral dose of both drugs to cure or achieve high efficacy in infected rats is 75 mg/kg. This review summarized research progress on tribendimidine, artesunate, and artemether in experimental animals infected with C. sinensis and other species of trematodes.

Effect of diesel exhaust particles on allergic reactions and airway responsiveness in ovalbumin-sensitized brown Norway rats.

We have previously demonstrated that exposure to diesel exhaust particles (DEP) prior to ovalbumin (OVA) sensitization in rats reduced OVA-induced airway inflammation. In the present study, Brown Norway rats were first sensitized to OVA (42.3 +/- 5.7 mg/m3) for 30 min on days 1, 8, and 15, then exposed to filtered air or DEP (22.7 +/- 2.5 mg/m3) for 4 h/day on days 24-28, and challenged with OVA on day 29. Airway responsiveness was examined on day 30, and animals were sacrificed on day 31. Ovalbumin sensitization and challenge resulted in a significant infiltration of neutrophils, lymphocytes, and eosinophils into the lung, elevated presence of CD4+ and CD8+ T lymphocytes in lung draining lymph nodes, and increased production of serum OVA-specific immunoglobulin (Ig)E and IgG. Diesel exhaust particles pre-exposure augmented OVA-induced production of allergen-specific IgE and IgG and pulmonary inflammation characterized by marked increases in T lymphocytes and infiltration of eosinophils after OVA challenge, whereas DEP alone did not have these effects. Although OVA-sensitized rats showed modest response to methacholine challenge, it was the combined DEP and OVA exposure that produced significant airway hyperresponsiveness in this animal model. The effect of DEP pre-exposure on OVA-induced immune responses correlated with an interactive effect of DEP with OVA on increased production of reactive oxygen species (ROS) and nitric oxide (NO) by alveolar macrophages (AM) and alveolar type II (ATII) cells, NO levels in bronchoalveolar lavage fluid, the induction of inducible NO synthase expression in AM and ATII cells, and a depletion of total intracellular glutathione (GSH) in AM and lymphocytes. These results show that DEP pre-exposure exacerbates the allergic responses to the subsequent challenge with OVA in OVA-sensitized rats. This DEP effect may be, at least partially, attributed to the elevated generation of ROS in AM and ATII cells, a depletion of GSH in AM and lymphocytes, and an increase in AM and ATII cell production of NO.

Substance P released from intrinsic airway neurons contributes to ozone-enhanced airway hyperresponsiveness in ferret trachea.

Exposure to ozone (O3) induces airway hyperresponsiveness mediated partly through the release of substance P (SP) from nerve terminals in the airway wall. Although substantial evidence suggests that SP is released by sensory nerves, SP is also present in neurons of airway ganglia. The purpose of this study was to investigate the role of intrinsic airway neurons in O3-enhanced airway responsiveness in ferret trachea. To remove the effects of sensory innervation, segments of ferret trachea were maintained in culture conditions for 24 h before in vitro exposure to 2 parts/million of O3 or air for 1 h. Sensory nerve depletion was confirmed by showing that capsaicin did not affect tracheal smooth muscle responsiveness to cholinergic agonist or contractility responses to electrical field stimulation (EFS). Contractions of isolated tracheal smooth muscle to EFS were significantly increased after in vitro O3 exposure, but the constrictor response to cholinergic agonist was not altered. Pretreatment with CP-99994, an antagonist of the neurokinin 1 receptor, attenuated the increased contraction to EFS after O3 exposure but had no effect in the air exposure group. The number of SP-positive neurons in longitudinal trunk ganglia, the extent of SP innervation to superficial muscular plexus nerve cell bodies, and SP nerve fiber density in tracheal smooth muscle all increased significantly after O3 exposure. The results show that release of SP from intrinsic airway neurons contributes to O3-enhanced tracheal smooth muscle responsiveness by facilitating acetylcholine release from cholinergic nerve terminals.