An experimental test of the growth rate hypothesis as a predictive framework for microevolutionary adaptation.

The growth rate hypothesis (GRH) posits that the relative body phosphorus content of an organism is positively related to somatic growth rate, as protein synthesis, which is necessary for growth, requires P-rich rRNA. This hypothesis has strong support at the interspecific level. Here, we explore the use of the GRH to predict microevolutionary responses in consumer body stoichiometry. For this, we subjected populations of the rotifer Brachionus calyciflorus to selection for fast population growth rate (PGR) in P-rich (HPF) and P-poor (LPF) food environments. With common garden transplant experiments, we demonstrate that in HP populations evolution toward increased PGR was concomitant with an increase in relative phosphorus content. In contrast, LP populations evolved higher PGR without an increase in relative phosphorus content. We conclude that the GRH has the potential to predict microevolutionary change, but that its application is contingent on the environmental context. Our results highlight the potential of cryptic evolution in determining the performance response of populations to elemental limitation of their food resources.

Herbivore consumers face different challenges along opposite sides of the stoichiometric knife-edge.

Anthropogenic activities have reshaped the relative supply rates of essential elements to organisms. Recent studies suggested that consumer performance is strongly reduced by food that is either very high or very low in relative phosphorus content. However, the generality of such 'stoichiometric knife-edge' and its underlying mechanisms are poorly understood. We studied the response of a planktonic rotifer to a 10-fold food carbon : phosphorus (C : P) gradient and confirmed the existence of the stoichiometric knife-edge. Interestingly, we observed a complete homeostatic breakdown associated with strong growth reductions at high food C : P. In contrast, at low food C : P, animals maintained homeostasis despite pronounced performance reductions. Our results suggest that the mechanisms underlying adverse effects of stoichiometric imbalance are determined by both the identity of elements that are limiting and those that are present in excess. Negative effects of excess P reveal an additional way of how eutrophication may affect consumers.

Two new chalcones from Shuteria sinensis.

Two new chalcones, 2',3,4,4'-tetrahydroxy-2-prenylchalcone (1) and 3-methoxy-2',4,4'-trihydroxy-2-prenylchalcone (2), together with two known compounds, munsericin (3) and 3,4-dihydroxylonchocarpin (4), were isolated from the ethanol extract of the whole plant of Shuteria sinensis. Their structures were identified by spectroscopic analysis methods, such as 1D and 2D NMR, along with HR-MS data. Glucose metabolism activity of four compounds was tested, compounds 3 and 4 showed effect on the glucose consumption of insulin-resistant HepG2 cells.

Cerebroside-A provides potent neuroprotection after cerebral ischaemia through reducing glutamate release and Ca²âº influx of NMDA receptors.

Excessive presynaptic glutamate release after cerebral ischaemia leads to neuronal death mainly through excessive calcium entry of N-methyl-D-aspartate receptors (NMDARs). Our recent study reported that cerebroside can open large-conductance Ca²âº-activated K⁺ (BKCa) channels. The present study evaluated the effects of cerebroside-A (CS-A), a single molecule isolated from an edible mushroom, on brain injury after focal or global ischaemia in adult male mice and rats. We herein report that treatment with CS-A after 60-min middle cerebral artery occlusion dose-dependently reduced the cerebral infarction with at least a 6-h efficacious time-window, which was partially blocked by the BKCa channel blocker charybdotoxin (CTX). Treatment with CS-A after 20 min global cerebral ischaemia (four-vessel occlusion) significantly attenuated the death of pyramidal cells in hippocampal CA1 area, which was also sensitive to CTX. CS-A, by opening the BKCa channel, could prevent excessive glutamate release after oxygen-glucose deprivation (OGD). In addition, CS-A could inhibit NMDAR Ca²âº influx, which did not require the activation of the BKCa channel. Furthermore, CS-A blocked the OGD-induced NMDAR-dependent long-term potentiation in hippocampal CA1 region. These findings indicate that treatment with CS-A after stroke exerts potent neuroprotection through prevention of excessive glutamate release and reduction of Ca²âº influx through NMDARs.

Astragaloside IV attenuates lipolysis and improves insulin resistance induced by TNFalpha in 3T3-L1 adipocytes.

Increased circulating free fatty acid (FFA) concentrations have been demonstrated to potentially link obesity, insulin resistance and cardiovascular diseases. Astragaloside IV (AS-IV) is a saponin which is widely used in traditional Chinese medicine to treat type 2 diabetes and cardiovascular diseases. The purpose of the present study was to examine the effects of AS-IV on the lipolysis and insulin resistance induced by tumor necrosis factor-alpha (TNFalpha) in cultured 3T3-L1 adipocytes. TNFalpha promotes lipolysis in mammal adipocytes via the mitogen activated protein kinase (MAPK) family resulting in reduced expression/function of perilipin. Application of AS-IV inhibited TNFalpha-induced accelerated lipolysis in a dose-dependent manner, which was compatible with suppressed phosphorylation of ERK1/2 and reversed the downregulation of perilipin. Moreover, TNFalpha induced downregulation of key enzymes in lipogenesis, including LPL, FAS and GPAT, were also attenuated by AS-IV. Further studies showed that AS-IV improved TNFalpha-induced insulin resistance in 3T3-L1 adipocytes. This study provides the first direct evidence of the antilipolytic action of AS-IV in adipocytes, which may allow this agent to decrease the circulating FFA levels, thus increase insulin sensitivity and treat cardiovascular diseases.

Ginsenoside Rb1 promotes adipogenesis in 3T3-L1 cells by enhancing PPARgamma2 and C/EBPalpha gene expression.

Evidence has accumulated that ginseng and its main active constituents, ginsenosides, possess anti-diabetic and insulin-sensitizing properties which may be partly realized by regulating adipocyte development and functions. In the present study, we explored the effect of ginsenoside Rb(1), the most abundant ginsenoside in ginseng root, on adipogenesis of 3T3-L1 cells. We found that with standard differentiation inducers, ginsenoside Rb(1) facilitated adipogenesis of 3T3-L1 preadipocytes in a dose-dependent manner; 10 microM Rb(1) increased lipid accumulation by about 56%. Treatment of differentiating adipocytes with 10 microM Rb(1) increased the expression of mRNA and protein of PPARgamma(2) and C/EBPalpha, as well as mRNA of ap2, one of their target genes. After the treatment of differentiating adipocytes with Rb(1), basal and insulin-mediated glucose uptake was significantly augmented, accompanied by the up-regulation of mRNA and protein level of GLUT4, but not of GLUT1. In addition, ginsenoside Rb(1) also inhibited the proliferation of preconfluent 3T3-L1 preadipocytes. Our data indicate that anti-diabetic and insulin-sensitizing activities of ginsenosides, at least in part, are involved in the enhancing effect on PPARgamma2 and C/EBPalpha expression, hence promoting adipogenesis.

Mechanisms of acupuncture and moxibustion in regulation of epithelial cell apoptosis in rat ulcerative colitis.

AIM: To investigate the effect of acupuncture and moxibustion on epithelial cell apoptosis and expression of Bcl-2, Bax, fas and FasL proteins in rat ulcerative colitis. METHODS: A rat model of ulcerative colitis was established by immunological methods and local stimulation. All rats were randomly divided into model control group (MC), electro-acupuncture group (EA), herbs-partition moxibustion group (HPM). Normal rats were used as normal control group (NC). Epithelial cell apoptosis and expression of Bcl-2, Bax, fas and FasL proteins were detected by TUNEL and immunohistochemical method respectively. RESULTS: The number of epithelial cell apoptosis in MC was significantly higher than that in NC, and was markedly decreased after the treatment with herbs-partition moxibustion or electro-acupuncture. The expression of Bcl-2, Bax, fas and FasL in colonic epithelial cells in MC was higher than that in NC, and was markedly down- regulated by herbs-partition moxibustion or electro-acupuncture treatment. CONCLUSION: The pathogenesis of ulcerative colitis in rats involves abnormality of apoptosis. Acupuncture and moxibustion can regulate the expression of Bcl-2, Bax, fas and FasL proteins and inhibit the apoptosis of epithelial cells of ulcerative colitis in rats by Bcl-2/Bax, fas/FasL pathways.

Morphological study on colonic pathology in ulcerative colitis treated by moxibustion.

AIM:To observe the therapeutic effect of moxibustion on ulcerative colitis and its influence on the colonic mucosal morphology.METHODS:Forty-six patients with ulcerative colitis were randomly divided into the moxibustion with herbal medicine underneath group and the western medicine group. Thirty patients were treated with the above moxibustion and 16 patients with Salicylaye fapyridine (SASP).The colonic mucosa of 13 patients in the moxibustion group was observed by colonoscopy before and after the treatment. Mucin was also analyzed by H.E and AB-PAS staining.RESULTS:Seventeen patients were clinically cured,12 were improved and 1 unchanged in the moxibustion group. In the control group, 5 patients were clinically cured,7 improved and 4 unchanged. Thirteen patients with active UC were taken as the subjects for histopathologic analysis in this study. The colonic mucosal lesions were remarkably improved and the characteristic of the mucin also changed. In most sections, the chronic inflammation of mucosa was geatly ameliorated (P< 0.01). The inflammatory cell infiltratation much decreased and neutrophils, disapeared in most sections (P<0.001). The goblet cells significantly increased (P<0.001); crypt paracrypt abscess or mucosal ulceration was seen(P<0.001).CONCLUSION:The rate of cure of ulcerative colitis by moxibustion with herbal medicine beneath is superior to that by SASP. This sort of moxibustion can effectively improve the colonic mucosal lesions and restore the proportion of mucoprotein to near normal.

Study of the mechanisms of acupuncture and moxibustion treatment for ulcerative colitis rats in view of the gene expression of cytokines.

AIM:To observe the effect of acupuncture and moxibustion on the expression of IL-1beta and IL-6 mRNA in ulcerative colitis rats.METHODS:The SD rat ulcerative colitis model was created by immunological method associated with local stimulation. Colonic mucosa was prepared from human fresh surgical colonic specimens, homogenized by adding appropriate amount of normal saline and centrifuged at 3000r/min. The supernatant was collected for measurement of protein conentration and then mixed with Freund adjuvant. This antigen fluid was first injected into the plantae of the model group rats, and then into their plantae, dorsa, inguina and abdominal cavities (noFreund adjuvant for the last injection) again on the 10th, 17th, 24th and 31st day. When a certain titer of serum anti colonic antibody was reached, 2% formalin and antigen fluid (no Freund adjuvant) were administered separately by enema. The ulcerative colitis rat model was thus set up. The animals were randomly divided into four groups: model control group (MC, n = 8), electro acupuncture group (EA, n = 8), herbs partition moxibustion group (HPM 8), normal control group (NC,n = 8). HPM: Moxa cones made of refined mugwort floss were placed on the medicinal pad (medicinal pad dispensing: Radix Aconiti praeparata, cortex Cinnamomi, etc) for Qihai (RN 6) and Tianshu (ST 25, bilateral) and ignited. Two moxa cones were used for each acupoint once a day and 14 times in all. EA: Tianshu (bilateral) and Qihai were stimulated by the intermittent pulse with 2Hz frequency, 4mA intensity for 20 minutes once a day and 14 times in all. After treatment, rats of all four groups were killed simultaneously. The spleen was separated and the distal colon was dissected. Total tissue RNA was isolated by the guanidinium thiocyanate phenol chloroform extraction method. RT-PCR technique was used to study the expression of IL-1 beta and IL-6 mRNA.RESULTS:IL-1 beta and IL-6 mRNAs were not detected in the spleen and colonic mucosa of the NC rats, whereas they were significantly expressed in that of the MC rats.IL-1 beta and IL-6 mRNAs were markedly lower in the EA and HPM rats than that in MC rats. There was no significant difference between the levels of IL-1 beta and IL-6 mRNAs in the EA and HPM rats. The expressions of IL-1 beta and IL-6 mRNAs were nearly the same in the spleen and colon of all groups.CONCLUSION:Acupuncture and moxibustion greatly inhibited the expression of IL-1 beta and IL-6 mRNA in the experimental ulcerative colitis rats.