The Ca increase by the sperm factor in physiologically polyspermic newt fertilization: Its signaling mechanism in egg cytoplasm and the species-specificity

The newt, Cynops pyrrhogaster, exhibits physiological polyspermic fertilization, in which several sperm enter an egg before egg activation. An intracellular Ca²⁺ increase occurs as a Ca²⁺ wave at each sperm entry site in the polyspermic egg. Some Ca²⁺ waves are preceded by a transient spike-like Ca²⁺ increase, probably caused by a tryptic protease in the sperm acrosome at the contact of sperm on the egg surface. The following Ca²⁺ wave was induced by a sperm factor derived from sperm cytoplasm after sperm–egg membrane fusion. The Ca²⁺ increase in the isolated, cell-free cytoplasm indicates that the endoplasmic reticulum is the major Ca²⁺ store for the Ca²⁺ wave. We previously demonstrated that citrate synthase in the sperm cytoplasm is a major sperm factor for egg activation in newt fertilization. In the present study, we found that the activation by the sperm factor as well as by fertilizing sperm was prevented by an inhibitor of citrate synthase, palmitoyl CoA, and that an injection of acetyl-CoA or oxaloacetate caused egg activation, indicating that the citrate synthase activity is necessary for egg activation at fertilization. In the frog, Xenopus laevis, which exhibits monospermic fertilization, we were unable to activate the eggs with either the homologous sperm extract or the Cynops sperm extract, indicating that Xenopus sperm lack the sperm factor for egg activation and that their eggs are insensitive to the newt sperm factor. The mechanism of egg activation in the monospermy of frog eggs is quite different from that in the physiological polyspermy of newt eggs.     

Statistical analysis of features associated with protein expression/solubility in an in vivo Escherichia coli expression system and a wheat germ cell-free expression system

Recombinant protein technology is an important tool in many industrial and pharmacological applications. Although the success rate of obtaining soluble proteins is relatively low, knowledge of protein expression/solubility under 'standard' conditions may increase the efficiency and reduce the cost of proteomics studies. In this study, we conducted a genome-scale experiment to assess the overexpression and the solubility of human full-length cDNA in an in vivo Escherichia coli expression system and a wheat germ cell-free expression system. We evaluated the influences of sequence and structural features on protein expression/solubility in each system and estimated a minimal set of features associated with them. A comparison of the feature sets related to protein expression/solubility in the in vivo Escherichia coli expression system revealed that the structural information was strongly associated with protein expression, rather than protein solubility. Moreover, a significant difference was found in the number of features associated with protein solubility in the two expression systems.     

Functionally different predators break down antipredator defenses of spider mites

Prey that lives with functionally different predators may experience enhanced mortality risk, because of conflicts between the specific defenses against their predators. Because natural communities usually contain combinations of prey and functionally different predators, examining risk enhancement with multiple predators may help to understand prey population dynamics. It is also important in an applied context: risk enhancement with multiple biological control agents could lead to successful suppression of pests. We examined whether risk enhancement occurs in the spider mite Tetranychus kanzawai Kishida (Acari: Tetranychidae) when exposed to two predator species: a generalist ant, Pristomyrmex punctatus Mayr (Hymenoptera: Formicidae), and a specialist predatory mite, Neoseiulus womersleyi Schicha (Acari: Phytoseiidae). We replicated microcosms that consisted of spider mites, ants, and predatory mites. Spider mites avoided generalist ants by staying inside their webs on leaf surfaces. In contrast, spider mites avoided specialist predatory mites that intruded into their webs by exiting the web, which obviously conflicts with the defense against ants. In the presence of both predators, enhanced mortality of spider mites was observed. A conflict occurred between the spider mites’ defenses: they seemed to move out of their webs and be preyed upon by ants. This is the first study to suggest that risk enhancement occurs in web‐spinning spider mites that are exposed to both generalist and specialist predator species, and to provide evidence that ants can have remarkable synergistic effects on the biological control of spider mites using specialist predatory mites.     

Tumour-suppressive microRNA-24-1 inhibits cancer cell proliferation through targeting FOXM1 in bladder cancer

Here, we found that microRNA-24-1 (miR-24-1) is significantly reduced in bladder cancer (BC) tissues, suggesting that it functions as a tumour suppressor. Restoration of mature miR-24-1 inhibits cancer cell proliferation and induces apoptosis. Forkhead box protein M1 (FOXM1) is a direct target gene of miR-24-1, as shown by genome-wide gene expression analysis and luciferase reporter assay. Overexpressed FOXM1 is confirmed in BC clinical specimens, and silencing of FOXM1 induces apoptosis in cancer cell lines. Our data demonstrate that the miR-24-1–FOXM1 axis contributes to cancer cell proliferation in BC, and elucidation of downstream signalling will provide new insights into the molecular mechanisms of BC oncogenesis.     

Silique burst ofCardamine scutata (Cruciferae) as a physical inducible defense against seed predatory caterpillars

Matured seeds of bitter cress,Cardamine scutata Thumb, are scattered by the bursting of siliques. They also burst in response to chewing by seed predatory caterpillars even when seeds are immature. In this case, the caterpillars are frequently expelled, or killed when their bodies become enswathed by the released pericarps. Consequently, many seeds escape from the attack. The plant trait is explained as an immediate induction of a physical defense against seed predators. The germination rate of scattered immature seeds was significantly lower than that of mature ones, which is a direct demonstration of trade-off between anti-herbivore defense and reproduction of the plant.     

Glomerular Endothelial Cell Injury and Focal Segmental Glomerulosclerosis Lesion in Idiopathic Membranous Nephropathy

Background

Focal segmental glomerulosclerosis (FSGS) lesions have often been discussed as a negative predictor in idopathic membranous nephropathy (MN). The mechanism of the development of FSGS lesion in MN is still uncertain.

Methods

From 250 cases of MN, 26 cases contained FSGS lesion. We compared the clinicopathological characteristics between MN cases with FSGS lesion [MN-FSGS(+)] and MN without FSGS lesion [MN-FSGS(−)], matched for gender, age, stage of MN.

Results

The glomerular filtration rate (eGFR) was significantly lower in MN-FSGS(+) cases compared to MN-FSGS(−), although nephrotic syndrome, hematuria, and systolic blood pressure levels were not significantly different between the two groups. Pathologically, glomeruli in MN-FSGS(+) cases showed narrowing and loss of glomerular capillaries with separating from GBM or disappearance of CD34+ endothelial cells, and accumulation of extracellular matrix (ECM) in capillary walls, indicating the development of glomerular capillary injury. These findings of endothelial injury were seen even in MN-FSGS(−) cases, but they were more prominent in MN-FSGS(+) than MN-FSGS(−) by computer assessed morphometric analysis. In MN-FSGS(+) cases, 44 out of 534 glomeruli (8.2%) contained FSGS lesions (n = 31, NOS lesion; n = 13, perihilar lesion). Significant thickness of GBM with ECM accumulation was evident in MN-FSGS(+) cases. Podocyte injury with effacement of foot processes was also noted, but the expression of VEGF on podocytes was not different between the two groups, which suggests that the significant thickness of capillary walls may influence the function of VEGF from podocyte resulting in the glomerular capillary injury that contribute to the development of FSGS lesion in MN.

Conclusion

Glomerular capillary injury was seen in all MN cases. Furthermore, the prominent injuries of glomerular capillaries may be associated with the deterioration of eGFR and the formation of FSGS lesions in MN.     

Effect of adoptive T-cell immunotherapy on immunological parameters and prognosis in patients with advanced pancreatic cancer

Background aimsImmunotherapy is effective for many types of cancer, but its benefits in advanced pancreatic cancer, which has a poor prognosis, are not well established. In this study, the authors examined the effects of adoptive T-cell immunotherapy (ATI) on immune cell profiles and prognosis in patients with unresectable advanced pancreatic cancer.MethodsSeventy-seven patients with unresectable advanced pancreatic cancer were treated with six cycles of αβ T cells alone or in combination with chemotherapy or chemoradiation. Immune cell profiles in peripheral blood samples obtained before and after treatment were comprehensively evaluated by flow cytometry. Furthermore, associations between changes in immune cell frequencies and prognosis were determined.ResultsATI prolonged survival to 18.7 months compared with previous estimates of 6.2–11.1 months for patients treated with chemotherapy alone. ATI decreased CD3+CD4+CD8? T cell frequency in peripheral blood and increased CD3+CD4?CD8+ T cell frequency. An increase in CD3+ T cells and CD3+TCRγδ? T cells in peripheral blood after treatment was associated with a good prognosis.ConclusionsATI altered the immune profile in peripheral blood, including CD3+CD4?CD8+ T cells, and improved prognosis in pancreatic cancer.     

Emulsifying Properties of a Mixture of Peptides Derived from the Enzymatic Hydrolyzates of Bovine Caseins

β-CN(f193–209), a hydrophobic peptide of 17 residues obtained from the chymosin hydrolyzate of β-casein, had little emulsifying activity (EA) at a neutral pH. When mixed with a hydrophilic glycomacropeptide (GMP) derived from κ-casein however, the EA of β-CN(f193-209) increased greatly. The mixing ratio of the peptides affected the EA as well as the adsorption of the peptides to oil droplets. Scanning electron microscopy indicated that the peptide film surrounding the emulsified oil droplets was thick and rough compared to the protein film. An amphipathic structure formed by some interaction between the hydrophilic GMP and the hydrophobic β-CN(f193-209) might contribute to the formation of the thick peptide film and stabilize the emulsified oil.