TCR- and CD28-mediated recruitment of phosphodiesterase 4 to lipid rafts potentiates TCR signaling

Ligation of the TCR along with the coreceptor CD28 is necessary to elicit T cell activation in vivo, whereas TCR triggering alone does not allow a full T cell response. Upon T cell activation of human peripheral blood T cells, we found that the majority of cAMP was generated in T cell lipid rafts followed by activation of protein kinase A. However, upon TCR and CD28 coligation, beta-arrestin in complex with cAMP-specific phosphodiesterase 4 (PDE4) was recruited to lipid rafts which down-regulated cAMP levels. Whereas inhibition of protein kinase A increased TCR-induced immune responses, inhibition of PDE4 blunted T cell cytokine production. Conversely, overexpression of either PDE4 or beta-arrestin augmented TCR/CD28-stimulated cytokine production. We show here for the first time that the T cell immune response is potentiated by TCR/CD28-mediated recruitment of PDE4 to lipid rafts, which counteracts the local, TCR-induced production of cAMP. The specific recruitment of PDE4 thus serves to abrogate the negative feedback by cAMP which is elicited in the absence of a coreceptor stimulus.     

Study of serum haptoglobin and its glycoforms in the diagnosis of hepatocellular carcinoma: a glycoproteomic approach

Increased serum haptoglobin concentration and changes in its glycosylation have been reported in certain cancer types. Information for hepatocellular carcinoma (HCC) has not yet been available. In this study, we aimed to carry out a systematic analysis of serum concentrations of haptoglobin (Hp) and its glycoforms in the patients with HCC and noncancer patients only with chronic liver diseases (CLD) and to examine their clinical values. This study was divided into two major parts, (1) measurement of serum Hp concentration, and investigation of its value in the diagnosis of HCC, and (2) quantitative analysis of Hp glycoforms with alpha-2,6-sialylation and/or alpha-1,6-fucosylation by using lectin affinity purification and 2D gel electrophoresis and investigation of their relationships with tumor stage. The concentrations of serum Hp in HCC patients were significantly higher than those in noncancer patients with CLD. With the use of serum concentrations of Hp and alpha-fetoprotein, a logistic regression (LR) model was developed from the training data set and used to classify the validation cases. At a specificity of 95%, the sensitivity for HCC detection was 79%. Comparing serum concentrations of alpha-2,6-sialylated Hp (S-Hp) and alpha-1,6-fucosylated Hp (F-Hp) between HCC and CLD patients suggests that purification of S-Hp and F-Hp could enrich the glycosylation variants associated with HCC. 2D gel analysis of S-Hp and F-Hp identified a total of 18 glycoforms. A unique pattern of Hp glycoforms comprising both hypersialylated fucosylated and hyposialylated fucosylated species was found in the HCC patients. Serum concentrations of these glycoproteins were significantly higher in the patients with advanced tumors, suggesting their tumor-specific nature. We have shown that serum Hp is a potential biomarker in the diagnosis of HCC. The combined use of Hp and AFP could greatly improve the diagnostic accuracy. A unique pattern of Hp glycoforms with altered sialylation and fucosylation is specific to HCC and associated tumor progression.     

Serum metabolomics for the diagnosis and classification of myasthenia gravis

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease with few reliable diagnostic measures. Therefore, it is great important to explore novel tools for the diagnosis of MG. In this study, a serum metabolomic approach based on LC?CMS in combination with multivariate statistical analyses was used to identify and classify patients with various grades of MG. Serum samples from 42 MG patients and 16 healthy volunteers were analyzed by liquid chromatography Fourier transform mass spectrometry (LC-FTMS). MG patients were clearly distinguished from healthy subjects based on their global serum metabolic profiles by using orthogonal partial least squares (OPLS) analysis. Moreover, different changes in metabolic profiles were observed between early- and late-stages MG patients. Nine biomarkers, including gamma-aminobutyric acid and sphingosine 1-phosphate were identified. In addition, 92.8% sensitivity, 83.3% specificity and 90% accuracy were obtained from the OPLS discriminant analysis (OPLS-DA) class prediction model in detecting MG. The results presented here illustrate that serum metabolomics exhibits great potential in the detecting and grading of MG, and it is potentially applicable as a new diagnostic approach for MG.     

The trypsin-inhibitory, immunostimulatory and antiproliferative activities of a napin-like polypeptide from Chinese cabbage seeds.

A heterodimeric 13.8 kDa napin-like polypeptide has previously been isolated from Chinese cabbage (Brassica parachinensis) seeds with a procedure involving ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, FPLC-ion exchange chromatography on Mono S and FPLC-gel filtration on Superdex 75. In the present study the N-terminal sequence of the 8.8 kDa subunit of the polypeptide (PQGPQQRPPKLLQQQTNEEHE) was found to have pronounced homology to napins, albumins and trypsin inhibitors, but demonstrated little similarity to the 5 kDa subunit. The polypeptide stimulated nitrite production by mouse peritoneal macrophages and reduced the viability of leukaemia (L1210) cells. It inhibited trypsin with a higher potency than it inhibited chymotrypsin, but was devoid of ribonuclease and antifungal activities.     

Pitcher plant facilitates prey capture in a sympatric congener

Carnivorous plants avoid below-ground competition for nitrogen by utilizing an alternative nitrogen resource—invertebrate prey, but it remains unclear if sympatric carnivorous plants compete for prey resources. The aim of this study was to investigate if exploitative prey-resource competition occurs between the two sympatric pitcher plant species, Nepenthes rafflesiana and N. gracilis in Singapore. We first investigated if prey-resource partitioning occurs between these two species, and then investigated niche shift in N. gracilis by examining its pitcher contents along an in situ gradient of N. rafflesiana interspecific competition. Our results showed clear evidence of resource partitioning between the two species, but contrary to the expectation of competition, proximity to N. rafflesiana pitchers correlated with higher total prey numbers in N. gracilis pitchers. Our multivariate model of prey assemblages further suggested that N. rafflesiana facilitates N. gracilis prey capture, especially in several ant taxa that are trapped by both species. Concurrently, we found strong evidence for intraspecific competition between N. gracilis pitchers, suggesting that prey resources are exhaustible by pitcher-predation. Our results show that resource partitioning can be associated with facilitative interactions, instead of competition as is usually assumed. Facilitation is more typically expected between phylogenetically distant species, but divergences in resource acquisition strategies can permit facilitation between congeners.     

Daphnia magna microRNAs respond to nutritional stress and ageing but are not transgenerational

Maternal effects, where the performance of offspring is determined by the condition of their mother, are widespread and may in some cases be adaptive. The crustacean Daphnia magna shows strong maternal effects: offspring size at birth and other proxies for fitness are altered when their mothers are older or when mothers have experienced dietary restriction. The mechanisms for this transgenerational transmission of maternal experience are unknown, but could include changes in epigenetic patterning. MicroRNAs (miRNAs) are regulators of gene expression that have been shown to play roles in intergenerational information transfer, and here, we test whether miRNAs are involved in D. magna maternal effects. We found that miRNAs were differentially expressed in mothers of different ages or nutritional state. We then examined miRNA expression in their eggs, their adult daughters and great granddaughters, which did not experience any treatments. The maternal (treatment) generation exhibited differential expression of miRNAs, as did their eggs, but this was reduced in adult daughters and lost by great granddaughters. Thus, miRNAs are a component of maternal provisioning, but do not appear to be the cause of transgenerational responses under these experimental conditions. MicroRNAs may act in tandem with egg provisioning (e.g., with carbohydrates or fats), and possibly other small RNAs or epigenetic modifications.     

Dopamine-beta-hydroxylase in dog lymph--effect of sympathetic activation

In anesthetized dogs baroreceptor denervation and electrical stimulation of the left stellate ganglion caused marked arterial hypertension and tachycardia. These were associated with a 4-10-fold increase in the total output of dopamine-β-hydroxylase (DβH) in the thoracic duct lymph. Serum DβH activity was lower than that in man and changes during sympathetic activation were inconsistent. These results suggest that a major portion of DβH released from adrenergic nerve terminals is transported in the lymph before it enters the circulating blood.     

Kinematic evaluation of cruciate-retaining total knee replacement patients during level walking: A comparison with the displacement-controlled ISO standard

Differences between wear-scar features of simulator-tested and retrieved tibial total knee replacement (TKR) liners have been reported. This disagreement may result from differences between in vivo kinematic profiles and those defined by the International Organization for Standardization (ISO). The purpose of this study was to determine the knee kinematics of a TKR subject group during level walking and compare them with the motion profiles defined by the ISO standard for a displacement-controlled knee wear testing simulator. Twenty-nine patients with a posterior cruciate ligament-retaining TKR design were gait tested using the point cluster technique to obtain flexion–extension (FE) rotation, anterior–posterior (AP) translation and internal–external (IE) rotation knee motions during a complete cycle of level walking. Relative ranges of motion and timing of key points within the in vivo motion data were compared against the same ranges and same key points from the input profiles of the displacement-controlled wear testing standard ISO14243-3. The subjects exhibited a FE pattern similar to ISO, with an insignificant difference in range of FE rotation from midstance to terminal stance. However, the subjects had a significantly higher range of knee flexion from terminal stance into swing. The subjects also exhibited a phase delay for the entire gait cycle. For AP translation, the standard profile had statistically significant lower magnitudes than seen in vivo. Opposite pattern of AP motion was also apparent from midstance and swing. Similarly, ISO specified a smaller IE total range of rotation with a motion pattern in complete opposition to that seen in vivo. In conclusion, significant differences were found in both the magnitudes and pattern of in vivo motion compared with ISO.     

Proteomic characterization of Phragmites communis in ecotypes of swamp and desert dune

Phragmites communis Trin. (common reed) is a recognized model plant for studying its adaptation to contrasting and harsh environments. To understand the inherent molecular basis for its remarkable resistance to combined stresses, we performed a comprehensive proteomic analysis of the leaf proteins from two ecotypes, i.e. swamp and desert dune, naturally growing in the desert region of northwestern China. First, a proteome reference map of Phragmites was established based on the swamp ecotype. Proteins were resolved by 2‐D/SDS‐PAGE and identified by MALDI‐TOF/TOF MS. In total, 177 spots were identified corresponding to 51 proteins. The major proteins identified are proteins involved in photosynthesis, glutathione and ascorbic acid metabolism as well as protein synthesis and quality control. Second, the 2‐DE profiles of the two ecotypes were compared quantitatively via DIGE analysis. Compared with swamp ecotype, 51 proteins spots are higher‐expressed and 58 protein spots are lower‐expressed by twofold or more in desert dune ecotype. Major differences were found for the proteins involved in light reaction of photosynthesis, protein biosynthesis and quality control and antioxidative reactions. The physiological significance of such differences is discussed in the context of a flow of complex events in relation to plant adaptation to combined environmental stresses.