Extrafloral nectary (EFN)-bearing plants attract ants to gain protection against herbivores. Some EFN-bearing plants possess different types of EFNs, which might have different effects on ants on the plants. Mallotus japonicus (Thunb.) Muell. Arg. (Euphorbiaceae) bears two types of EFNs, including a pair of large EFNs at the leaf base and many small EFNs along the leaf edge. This study aimed to determine the different roles of the two types of EFNs in biotic defense by ants. A field experiment was conducted to investigate the effect of leaf damage on EFN production and on the distribution pattern of ants. After leaf damage, the number of leaf edge EFNs increased in the leaves first-produced. The number of ants on the leaves also increased, and the foraging area of ants extended from the leaf base to the leaf tip. An EFN-covering field experiment revealed that leaf edge EFNs had a greater effect than leaf base EFNs on ant dispersal on leaves. The extended foraging area of ants resulted in an increase of encounter or attack rate against an experimentally placed herbivore, Spodoptera litura. These results suggest that M. japonicus plants control the foraging area of ants on their leaves using different types of EFNs in response to leaf damage, thus achieving a very effective biotic defense against herbivores by ants.
Glomerular podocytes are pivotal in maintaining glomerular filtration barrier function. As severe podocyte injury results in proteinuria in patients with diabetic nephropathy, determining the pathogenesis of podocyte injury may contribute to the development of new treatments. We recently showed that autophagy is involved in the pathogenesis of diabetes-related podocyte injury. Insufficient podocyte autophagy and podocyte loss are observed in diabetic patients with massive proteinuria. Podocyte loss and massive proteinuria occur in high-fat diet-induced diabetic mice with podocyte-specific autophagy deficiency, with podocytes of these mice and of diabetic rats having huge damaged lysosomes. Sera from diabetic patients and from rodents with massive proteinuria cause autophagy insufficiency, resulting in lysosome dysfunction and apoptosis of cultured podocytes. These findings suggest the importance of autophagy in maintaining lysosome homeostasis in podocytes under diabetic conditions. Impaired autophagy may be involved in the pathogenesis of podocyte loss, leading to massive proteinuria in diabetic nephropathy. 相似文献
Tungsten particles have long been used as microcarriers in biolistic bombardment because of their cost-effectiveness compared
to alternative gold particles—even if the former have several drawbacks, including their DNA-degrading activity. We characterized
tungsten-induced DNA degradation to assess the value of this metal particle and to improve tungsten-based biolistic bombardment.
Alkaline pH, low temperature, and high salt concentration were found to diminish tungsten-induced DNA breakdown. The pH was
the most influential factor in this phenomenon, both in aqueous solutions and on the particles. Furthermore, alkaline pH greater
than 9.4 of an adsorption mixture was found to be essential for DNA binding to metal particles. Based on these findings, we
propose a new formula of DNA/tungsten adsorption by using TE buffers that keep alkaline pH (>9.4) of the mixture, in which
tungsten-bound plasmid DNA cleavage was suppressed to half the level of that in the conventional DNA-binding condition. 相似文献
This study examined the ontogenetic change in vertical distribution associated with algae and the thyroid hormone profiles
of black rockfish (Sebastes schlegelii) under rearing conditions. Experimental observations on distribution were carried on black rockfish from the newly born
larval stage to juveniles 75 days after birth (DAB). Position was categorized by vertical location [upper layer, mid layer
and lower layer (LL)] and by association with artificial algae (floating algae, bottom algae and no association). Position
of fish was observed four times a day, at 0400 (dawn), 1200 (noon), 1800 (dusk) and 2400 (midnight) hours. The majority of
fish (>80%) reached transforming larval stage [17.8 ± 0.7 mm total length (TL)] at 25 DAB and juvenile stage (24.3 ± 0.6 mm
TL) at 35 DAB. Newly born larvae were mainly distributed at surface and middle layers, the shift of vertical distribution
to the LL occurred between 10 and 25 DAB, and over 98% of the individuals were distributed near the bottom after 35 DAB. Association
behavior with algae was first observed from 20 to 30 DAB depending on the time of day. Percentage of fish associated with
bottom algae increased from 25 to 40 DAB and reached 50–70% thereafter. Thyroid hormone (T4) showed two surges at 30 and 50 DAB. The first surge corresponded to the transforming larval stage and the occurrence of
association behavior with algae. The results indicate that pelagic larvae settle to the bottom layer before metamorphosis,
and association behavior with algae appears at the transforming larval stage. A high T4 concentration at 30 DAB indicates a close relationship with these morphological and behavioral developments. 相似文献
In order to clarify the mechanisms of neoteny in the ice goby (Leucopsarion petersii), we examined effects of thyroid hormone and thiourea (TU) treatments on their neotenic characteristics and the pituitary-thyroid axis. Adult ice goby were exposed to 3, 5, 3'-triiodothyronine (T3, 0.1 ppm), TU (inhibitor of thyroid hormone synthesis, 30 ppm), or the combination of the two for 2 weeks. Observations of whole body T3 levels, thyroid follicles and TSH immunoreactive cells in the pituitary suggests the presence of a functioning thyroidal system. However, all of the neotenic features did not disappear in T3-treated fish, suggesting the absence of T3 responsiveness in peripheral tissues. These results indicate the similarity between neoteny of the ice goby and obligatory-type neoteny of urodeles. 相似文献
Crystalline 1 (TAK-599) is a novel N-phosphono prodrug of anti-methicillin-resistant Staphylococcus aureus (MRSA) cephalosporin 2a (T-91825) that has high affinity for penicillin-binding protein (PBP) 2' (IC(50); 0.90 microg/mL) and shows potent in vitro anti-MRSA activity (MIC against MRSA N133; 1.56 microg/mL), comparable to that of vancomycin (1.56 microg/mL). Although 2a had insufficient water solubility (2.3 mg/mL) for parenteral administration, 1 showed excellent water solubility (>100 mg/mL, pH 7) as well as good chemical stability in the solid state and solution. In pharmacokinetic studies, when 1 was administered intravenously to rats and monkeys, it was rapidly converted into 2a in the blood. These results show that 1 (TAK-599) is a highly promising parenteral cephalosporin targeted for MRSA infection. 相似文献