Reproductive development and maternal effects in the pine weevil Hylobius abietis

1. In a laboratory study of maturation feeding of female pine weevil Hylobius abietis on current and 1‐year‐old stem bark of transplants of Scots and Corsican pine, Norway and Sitka spruce, Douglas fir, and hybrid larch, the length of the pre‐oviposition period was influenced by the species on which weevils fed. The shortest pre‐oviposition period was on hybrid larch (11.8 days) and the longest on Douglas fir (15.5 days). 2. The species on which weevils fed also affected fecundity but there was evidence of a species–year interaction. Over a period of 36 days, most eggs were laid by weevils feeding on current stem of Norway spruce and Corsican and Scots pine and fewest on current stem of Sitka spruce. 3. Significant maternal effects on egg size were observed both in relation to female size and conifer species. The largest eggs were laid on Corsican pine and the smallest on Douglas fir, with no evidence of a trade‐off between number of eggs laid and their size. 4. There was a positive relationship between egg and larval size and between larval size and survival on logs of four conifer species. Residual resistance mechanisms in the bark of recently cut stumps and larval competition are discussed briefly in relation to the importance of the observed maternal effects on weevil population dynamics.     

How do caterpillars cope with xenobiotics? The case of Mythimna unipuncta,a species with low susceptibility to Bt

Mythimna unipuncta is a species with low susceptibility to the Bacillus thuringiensis (Bt) toxin, and this insect occasionally causes devastating damage to maize. In the study region, M. unipuncta‐developed larvae were observed moving from a non‐Bt crop to a nearby Bt crop. Although the first response of many caterpillars to xenobiotics, such as the Bt toxin, is to reduce food intake and prolong development, few studies have focused on the causes and consequences of this response in terms of resistance evolution. To clarify the causes of this response, this work compared changes in the feeding behaviour, cytochrome P450 expression and juvenile hormone titre during the last larval instar of M. unipuncta after Bt ingestion. Four P450 enzymes related to the xenobiotic metabolism of the CYP9 and CYP6 families were identified. Developed larvae fed the Bt diet reduced their food intake and CYP9 expression, experienced prolonged development and presented an altered juvenile hormone balance. The CYP9s were not increased in the larvae that consumed Bt, as previously expected, although their highest expression was observed when larval feeding increased. The high recovery capacity of the larvae contributed to their development when they were fed a non‐Bt diet. The efficiency of responses that act jointly as a defence mechanism against Bt might favour the development of field resistance to the toxin. Therefore, these responses should be further investigated for resistance management programmes.     

Primitive Defence: The MiAMP1 Antimicrobial Peptide Family

The founder of the MiAMP1 protein family was originally isolated from Macadamia integrifolia and had antimicrobial activity in vitro. MiAMP1 was the first plant protein with a structure containing a βγ-crystallin precursor fold, a structural superfamily associated with antimicrobial proteins in other kingdoms. In recent times, expanding plant genomics information has revealed that genes encoding homologues of MiAMP1 are conserved across the plant kingdom from lycophytes, gymnosperms to early angiosperms (e.g. Amborella, Papaver) and some monocots (e.g. Zantedeschia, Zea, Sorghum). Many studies of plant–pathogen interactions in gymnosperms have demonstrated a potential role for MiAMP1 family members in defence against fungal pathogens. This commentary describes the discovery and diversity of this protein family and considers current evidence supporting, and future opportunities for substantiating, a role in defence in primitive plants, and why this role may have diminished in higher plants.     

Oxidative DNA base damage, antioxidant enzyme activities and selenium status in highly iodine-deficient goitrous children

The objective of this study was to investigate oxidative DNA damage, and the levels of antioxidant enzymes (AOE) and selenium (Se) in relation to iodine deficiency and/or goiter in children. The study was performed in a group of goitrous high school children (15-18 years of age) ( n =14) with severe or moderate iodine deficiency. Thyroid hormones (TSH, FT 4 , TT 4 , FT 3 , TT 3 ), urinary iodine (UI) and plasma Se levels, and erythrocyte glutathione peroxidase (GSHPx), superoxide dismutase (SOD) and catalase (CAT) activities were determined and compared with those of a control group consisting of non-goitrous high school children ( n =14) with normal UI levels or mild iodine deficiency. In the goitrous group, concentrations of FT 4 , TT 4 , plasma Se and UI, and activities of GSHPx and SOD were found to be significantly lower. Six typical hydroxyl radical-induced base lesions in genomic DNA of peripheral blood were identified and quantified by gas chromatography/isotope-dilution mass spectrometry (GC/IDMS), and higher levels of DNA base lesions were observed in the goitrous group. The results suggest that highly iodine-deficient goitrous children may be under oxidative stress, which may lead to greater level of oxidative damage to DNA. This study supports the evidence for the reported relationship between iodine deficiency and the increased incidence of thyroid malignancies.     

竹荪的菌丝培养及其抗菌性的初步研究

对长裙竹荪（Ｄｉｃｔｙｏｐｈｏｒａ　ｉｎｄｕｓｉａｔａ）等３种的菌丝培养进行了研究并初步测定菌丝的抗菌谱。培养液的 ｐＨ和液体培养基粘度是竹荪在液体中生长的关键因素,在 ｐＨ４.７和添加 ０.５％ＣＭＣ－Ｎａ的合适培养条件下竹荪菌丝在液体中能够生长,菌丝得率达到１％。还探讨了其他几种竹荪菌丝的培养方法,为竹荪菌丝的大量生产提供了依据。另外,在竹荪抗菌性实验中发现,竹荪对许多易造成食品腐败的细菌和酵母具有抗性,但没有发现其对霉菌有抗性。     

Social relationships and individual contribution to cooperative behaviour in captive common marmosets (Callithrix jacchus)

The social relationships between the members of a family consisting of eight captive common marmosets (Callithrix jacchus) are here examined, as well as the participation of individual family members in infant carrying and defensive behaviour against non-related intruders (adolescent males). Within the social relationships, a clear division of the family into three subgroups (parents, adult offspring, non-adult offspring) could be determined, whereby the adult offspring, especially with respect to the parents, occupy a peripheral position. In the types of cooperative behaviour examined here, substantial participation in infant carrying could be observed in only four family members (parents, adult son, one subadult daughter), and in defence against intruders in only two family members (adult son, one subadult daughter). Participation in infant carrying remained stable throughout the study period. Conversely, individual changes in participation in defence against intruders could be determined, dependent upon the presence of infants carried. The advantages and disadvantages of social substructuring observed are discussed here, in particular the peripheral position of adult offspring, possible connections in individually varied participation in cooperative behaviour, and possible regulative mechanisms. In view of past studies on cooperative behaviour among marmosets, it is here presumed that pronounced individual differences result from a division of labour within the family with respect to various aspects of cooperative behaviour.     

不同温度对木瓜秀粉蚧保护酶活性影响

为初步探讨木瓜秀粉蚧的温度适应性机理,本研究采用紫外分光光度法测定分析了不同温度饲养条件下木瓜秀粉蚧体内过氧化物酶(POD)、多酚氧化酶(PPO)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性差异。保护酶活性测定结果表明,与28℃相比,12℃、16℃、36℃和40℃下的POD、PPO、CAT和SOD的活性显著增加,分别为28℃的195.5%、187.7%、154.5%和162.1%,182.5%、158.6%、137.4%和152.1%,183.3%、166.7%、145.3%和181.8%,193.0%、179.8%、167.1%和191.9%,而20℃、24℃和32℃下各保护酶活性与28℃相比无显著差异。本研究结果表明,16℃以下低温和36℃以上高温可以诱导木瓜秀粉蚧保护酶活性显著提高,可能会对其生长发育产生不利影响,为深入开展木瓜秀粉蚧的生态适应性机理研究提供科学依据。     

Thyroid Hormone Receptor Interacting Protein 13 (TRIP13) AAA-ATPase Is a Novel Mitotic Checkpoint-silencing Protein

The mitotic checkpoint (or spindle assembly checkpoint) is a fail-safe mechanism to prevent chromosome missegregation by delaying anaphase onset in the presence of defective kinetochore-microtubule attachment. The target of the checkpoint is the E3 ubiquitin ligase anaphase-promoting complex/cyclosome. Once all chromosomes are properly attached and bioriented at the metaphase plate, the checkpoint needs to be silenced. Previously, we and others have reported that TRIP13 AAA-ATPase binds to the mitotic checkpoint-silencing protein p31^comet. Here we show that endogenous TRIP13 localizes to kinetochores. TRIP13 knockdown delays metaphase-to-anaphase transition. The delay is caused by prolonged presence of the effector for the checkpoint, the mitotic checkpoint complex, and its association and inhibition of the anaphase-promoting complex/cyclosome. These results suggest that TRIP13 is a novel mitotic checkpoint-silencing protein. The ATPase activity of TRIP13 is essential for its checkpoint function, and interference with TRIP13 abolished p31^comet-mediated mitotic checkpoint silencing. TRIP13 overexpression is a hallmark of cancer cells showing chromosomal instability, particularly in certain breast cancers with poor prognosis. We suggest that premature mitotic checkpoint silencing triggered by TRIP13 overexpression may promote cancer development.     

Induced resistance in intertidal macroalgae modifies feeding behaviour of herbivorous snails

Herbivory in terrestrial and marine systems can induce changes in plant chemistry affecting the foraging behaviour of herbivores. A model based on terrestrial plant-herbivore interactions predicts herbivory-induced changes in leaf chemistry to be manifested in (1) increased herbivore mobility, (2) increased feeding dispersal and (3) reduced tissue consumption by herbivores. This study is the first to demonstrate that herbivory-induced changes in the tissue chemistry of the brown seaweed Ascophyllum nodosum elicit the same response in the feeding behaviour of the gastropod Littorina obtusata as predicted for herbivorous insects, providing good evidence for the models validity across different ecosystems. The potential benefit of increased feeding dispersal to terrestrial plants as suggested by the model is the prevention of concentrated damage to apical tissues thereby preserving the plants ability to compete for light; A. nodosum does not conform to these predictions. Increased dispersal of feeding damage on A. nodosum away from primary frond tissues would reduce the likelihood of frond breakage implying a fitness benefit of induced resistance.