Examination of Parental Effect on the Progeny Diapause by Reciprocal Cross Test in the Cabbage Beetle, Colaphellus bowringi

The cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae), a serious pest of crucifers in China, undergoes summer or winter diapause in the soil as an adult. In the present study, the incidence of diapause were measured in reciprocal crosses between a high—diapause strain (HD strain) and a laboratory—selected nondiapausing strain (ND strain) under different photoperiods and temperatures, to explore parental influences on the progeny diapause. Sensitivity to photoperiod in the selected nondiapausing strain was nearly eliminated at 25 °C, whereas sensitivity to temperature of the selected nondiapausing strain was retained under continuous darkness at 20 and 22 °C. Reciprocal crosses between the HD strain and the ND strain showed that the incidence of diapause in the progeny was always intermediate to that of the parents under different photoperiods and temperatures, suggesting that diapause induction was determined by both female and male parents. There was a significant effect of temperature; temperature interacted with reciprocal cross on diapause induction, whereas no significant effect of reciprocal cross was demonstrated. The incidence of diapause in ♀ND × ♂HD was the same as in ♀HD × ♂ND under continuous darkness at 18 °C (100%) and 26 °C (0%), but the former was higher than that in ♀HD × ♂ND under continuous darkness at 22 °C, suggesting that female parent does not exhibit strong influence on the diapause response to temperature. There was a significant effect of photoperiod and reciprocal cross on diapause induction, whereas no significant interactive effect on diapause induction was demonstrated. Incidence of diapause in ♀HD × ♂ND was always higher than in ♀ND × ♂HD at 25 °C and 12:12 L:D, 14:10 L:D, and 16:8 L:D, suggesting a strong maternal influence on the diapause response to photoperiod, though a significant difference was observed only at 14:10 L:D. Our results support the idea that diapause induction is determined by both female and male parents. However, results also indicated that a strong maternal influence on diapause was exhibited only in response to photoperiod

High Frequency of CD4+CXCR5+ TFH Cells in Patients with Immune-Active Chronic Hepatitis B

BACKGROUND: T follicular helper (TFH) cells are a special subpopulation of T helper cells and can regulate humoral immune responses. This study examined whether the frequency of CD4(+)CXCR5(+) TFH cells could be associated with active immunity in chronic hepatitis B (CHB) patients. METHODOLOGY AND FINDINGS: The frequencies of peripheral blood CD4(+)CXCR5(+) TFH cells, inducible T cell costimulator (ICOS), and/or programmed death 1 (PD-1) positive CD4(+)CXCR5(+) TFH cells in immune-active (IA), immune-tolerant (IT) CHB, and healthy controls (HC) were characterized by flow cytometry analysis. The effect of adevofir dipivoxil treatment on the frequency of CD4(+)CXCR5(+) TFH cells, the concentrations of serum IL-2, IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-21, ALT, AST, HBsAg, HBsAb, HBeAg, HBeAb and HBV loads in IA patients were determined. The potential association of the frequency of CD4(+)CXCR5(+) TFH cells with clinical measures was analyzed. In addition, the frequency of splenic and liver CD4(+)CXCR5(+) TFH cells in HBV-transgenic mice was examined. We found that the frequency of CD4(+)CXCR5(+) TFH cells in IA patients was significantly higher than that of IT patients and HC, and the percentages of CD4(+)CXCR5(+) TFH in IA patients were positively correlated with AST. Furthermore, the percentages of ICOS(+), PD-1(+), and ICOS(+)PD-1(+) in CD4(+)CXCR5(+) TFH cells in CHB patients were significantly higher than that of HC. Treatment with adefovir dipivoxil reduced the frequency of CD4(+)CXCR5(+) TFH, PD-1(+)CD4(+)CXCR5(+) TFH cells and the concentrations of HBsAg and HBeAg, but increased the concentrations of HBsAb, HBeAb, IL-2 and IFN-γ in IA patients. Moreover, the frequency of splenic and liver CD4(+)CXCR5(+) TFH cells in HBV-transgenic mice was higher than that of wild-type controls. CONCLUSIONS: These data indicate that CD4(+)CXCR5(+) TFH cells may participate in the HBV-related immune responses and that high frequency of CD4(+)CXCR5(+) TFH cells may be a biomarker for the evaluation of active immune stage of CHB patients

New insights into the photochemistry of carotenoid spheroidenone in light-harvesting complex 2 from the purple bacterium Rhodobacter sphaeroides

Light-harvesting complex 2 (LH2) from the semi-aerobically grown purple phototrophic bacterium Rhodobacter sphaeroides was studied using optical (static and time-resolved) and resonance Raman spectroscopies. This antenna complex comprises bacteriochlorophyll (BChl) a and the carotenoid spheroidenone, a ketolated derivative of spheroidene. The results indicate that the spheroidenone-LH2 complex contains two spectral forms of the carotenoid: (1) a minor, ‘‘blue’’ form with an S2 (11 Bu ?) spectral origin band at 522 nm, shifted from the position in organic media simply by the high polarizability of the binding site, and (2) the major, ‘‘red’’ form with the origin band at 562 nm that is associated with a pool of pigments that more strongly interact with protein residues, most likely via hydrogen bonding. Application of targeted modeling of excited-state decay pathways after carotenoid excitation suggests that the high (92%) carotenoid-to-BChl energy transfer efficiency in this LH2 system, relative to LH2 complexes binding carotenoids with comparable double-bond conjugation lengths, derives mainly from resonance energy transfer from spheroidenone S2 (11 Bu ?) state to BChl a via the Qx state of the latter, accounting for 60% of the total transfer. The elevated S2 (11 Bu ?) ? Qx transfer efficiency is apparently associated with substantially decreased energy gap (increased spectral overlap) between the virtual S2 (11 Bu ?) ? S0 (11 Ag -) carotenoid emission and Qx absorption of BChl a. This reduced energetic gap is the ultimate consequence of strong carotenoid–protein interactions, including the inferred hydrogen bondin

Determination of the Proteolytic Cleavage Sites of the Amyloid Precursor-Like Protein 2 by the Proteases ADAM10, BACE1 and γ-Secretase

Regulated intramembrane proteolysis of the amyloid precursor protein (APP) by the protease activities α-, β- and γ-secretase controls the generation of the neurotoxic amyloid β peptide. APLP2, the amyloid precursor-like protein 2, is a homolog of APP, which shows functional overlap with APP, but lacks an amyloid β domain. Compared to APP, less is known about the proteolytic processing of APLP2, in particular in neurons, and the cleavage sites have not yet been determined. APLP2 is cleaved by the β-secretase BACE1 and additionally by an α-secretase activity. The two metalloproteases ADAM10 and ADAM17 have been suggested as candidate APLP2 α-secretases in cell lines. Here, we used RNA interference and found that ADAM10, but not ADAM17, is required for the constitutive α-secretase cleavage of APLP2 in HEK293 and SH-SY5Y cells. Likewise, in primary murine neurons knock-down of ADAM10 suppressed APLP2 α-secretase cleavage. Using mass spectrometry we determined the proteolytic cleavage sites in the APLP2 sequence. ADAM10 was found to cleave APLP2 after arginine 670, whereas BACE1 cleaves after leucine 659. Both cleavage sites are located in close proximity to the membrane. γ-secretase cleavage was found to occur at different peptide bonds between alanine 694 and valine 700, which is close to the N-terminus of the predicted APLP2 transmembrane domain. Determination of the APLP2 cleavage sites enables functional studies of the different APLP2 ectodomain fragments and the production of cleavage-site specific antibodies for APLP2, which may be used for biomarker development

Oral treatment with a zinc complex of acetylsalicylic acid prevents diabetic cardiomyopathy in a rat model of type-2 diabetes: activation of the Akt pathway.

BACKGROUND: Type-2 diabetics have an increased risk of cardiomyopathy, and heart failure is a major cause of death among these patients. Growing evidence indicates that proinflammatory cytokines may induce the development of insulin resistance, and that anti-inflammatory medications may reverse this process. We investigated the effects of the oral administration of zinc and acetylsalicylic acid, in the form of bis(aspirinato)zinc(II)-complex Zn(ASA)2, on different aspects of cardiac damage in Zucker diabetic fatty (ZDF) rats, an experimental model of type-2 diabetic cardiomyopathy. METHODS: Nondiabetic control (ZL) and ZDF rats were treated orally with vehicle or Zn(ASA)2 for 24 days. At the age of 29-30 weeks, the electrical activities, left-ventricular functional parameters and left-ventricular wall thicknesses were assessed. Nitrotyrosine immunohistochemistry, TUNEL-assay, and hematoxylin-eosin staining were performed. The protein expression of the insulin-receptor and PI3K/AKT pathway were quantified by Western blot. RESULTS: Zn(ASA)2-treatment significantly decreased plasma glucose concentration in ZDF rats (39.0 +/- 3.6 vs 49.4 +/- 2.8 mM, P < 0.05) while serum insulin-levels were similar among the groups. Data from cardiac catheterization showed that Zn(ASA)2 normalized the increased left-ventricular diastolic stiffness (end-diastolic pressure-volume relationship: 0.064 +/- 0.008 vs 0.084 +/- 0.014 mmHg/microl; end-diastolic pressure: 6.5 +/- 0.6 vs 7.9 +/- 0.7 mmHg, P < 0.05). Furthermore, ECG-recordings revealed a restoration of prolonged QT-intervals (63 +/- 3 vs 83 +/- 4 ms, P < 0.05) with Zn(ASA)2. Left-ventricular wall thickness, assessed by echocardiography, did not differ among the groups. However histological examination revealed an increase in the cardiomyocytes' transverse cross-section area in ZDF compared to the ZL rats, which was significantly decreased after Zn(ASA)2-treatment. Additionally, a significant fibrotic remodeling was observed in the diabetic rats compared to ZL rats, and Zn(ASA)2-administered ZDF rats showed a similar collagen content as ZL animals. In diabetic hearts Zn(ASA)2 significantly decreased DNA-fragmentation, and nitro-oxidative stress, and up-regulated myocardial phosphorylated-AKT/AKT protein expression. Zn(ASA)2 reduced cardiomyocyte death in a cellular model of oxidative stress. Zn(ASA)2 had no effects on altered myocardial CD36, GLUT-4, and PI3K protein expression. CONCLUSIONS: We demonstrated that treatment of type-2 diabetic rats with Zn(ASA)2 reduced plasma glucose-levels and prevented diabetic cardiomyopathy. The increased myocardial AKT activation could, in part, help to explain the cardioprotective effects of Zn(ASA)2. The oral administration of Zn(ASA)2 may have therapeutic potential, aiming to prevent/treat cardiac complications in type-2 diabetic patients

Formation and Toxicity of Soluble Polyglutamine Oligomers in Living Cells

Aggregation and cytotoxicity of mutant proteins containing an expanded number of polyglutamine (polyQ) repeats is a hallmark of several diseases, including Huntington's disease (HD). Within cells, mutant Huntingtin (mHtt) and other polyglutamine expansion mutant proteins exist as monomers, soluble oligomers, and insoluble inclusion bodies (IBs). Determining which of these forms constitute a toxic species has proven difficult. Recent studies support a role for IBs as a cellular coping mechanism to sequester levels of potentially toxic soluble monomeric and oligomeric species of mHtt.When fused to a fluorescent reporter (GFP) and expressed in cells, the soluble monomeric and oligomeric polyglutamine species are visually indistinguishable. Here, we describe two complementary biophysical fluorescence microscopy techniques to directly detect soluble polyglutamine oligomers (using Htt exon 1 or Htt(ex1)) and monitor their fates in live cells. Photobleaching analyses revealed a significant reduction in the mobilities of mHtt(ex1) variants consistent with their incorporation into soluble microcomplexes. Similarly, when fused to split-GFP constructs, both wildtype and mHtt(ex1) formed oligomers, as evidenced by the formation of a fluorescent reporter. Only the mHtt(ex1) split-GFP oligomers assembled into IBs. Both FRAP and split-GFP approaches confirmed the ability of mHtt(ex1) to bind and incorporate wildtype Htt into soluble oligomers. We exploited the irreversible binding of split-GFP fragments to forcibly increase levels of soluble oligomeric mHtt(ex1). A corresponding increase in the rate of IBs formation and the number formed was observed. Importantly, higher levels of soluble mHtt(ex1) oligomers significantly correlated with increased mutant cytotoxicity, independent of the presence of IBs.Our study describes powerful and sensitive tools for investigating soluble oligomeric forms of expanded polyglutamine proteins, and their impact on cell viability. Moreover, these methods should be applicable for the detection of soluble oligomers of a wide variety of aggregation prone proteins

Therapeutic Potential of HDL in Cardioprotection and Tissue Repair

Epidemiological studies support a strong association between high-density lipoprotein (HDL) cholesterol levels and heart failure incidence. Experimental evidence from different angles supports the view that low HDL is unlikely an innocent bystander in the development of heart failure. HDL exerts direct cardioprotective effects, which are mediated via its interactions with the myocardium and more specifically with cardiomyocytes. HDL may improve cardiac function in several ways. Firstly, HDL may protect the heart against ischaemia/reperfusion injury resulting in a reduction of infarct size and thus in myocardial salvage. Secondly, HDL can improve cardiac function in the absence of ischaemic heart disease as illustrated by beneficial effects conferred by these lipoproteins in diabetic cardiomyopathy. Thirdly, HDL may improve cardiac function by reducing infarct expansion and by attenuating ventricular remodelling post-myocardial infarction. These different mechanisms are substantiated by in vitro, ex vivo, and in vivo intervention studies that applied treatment with native HDL, treatment with reconstituted HDL, or human apo A-I gene transfer. The effect of human apo A-I gene transfer on infarct expansion and ventricular remodelling post-myocardial infarction illustrates the beneficial effects of HDL on tissue repair. The role of HDL in tissue repair is further underpinned by the potent effects of these lipoproteins on endothelial progenitor cell number, function, and incorporation, which may in particular be relevant under conditions of high endothelial cell turnover. Furthermore, topical HDL therapy enhances cutaneous wound healing in different models. In conclusion, the development of HDL-targeted interventions in these strategically chosen therapeutic areas is supported by a strong clinical rationale and significant preclinical data.status: publishe