Competitive interaction between two ichneumonid parasitoids of Spodoptera litura

The outcome of competition between Campoletis chlorideae Uchida and Eriborus argenteopilosus (Cameron) (Hymenoptera: Ichneumonidae), two indigenous larval parasitoids of the noctuid pest, Spodoptera litura (Fabricius), was investigated in the laboratory by way of two experiments. In the individual exposure experiment, the host larvae were exposed to the parasitoids either alone or one after the other at different time intervals and were considered to be parasitised when the parasitoid was observed to sting the host larva. When they stung the host larva singly, the parasitism rates by C. chlorideae and E. argenteopilosus was either similar to or higher than the parasitism recorded by each parasitoid in the different combination/interaction treatments. C. chlorideae cocoons were formed from majority of the host larvae, which were stung by both parasitoid species, one after the other, in most oviposition orders and delays between ovipositions. E. argenteopilosus appeared to be the dominant parasitoid only in those treatments where it was the first one to parasitise and the delay in C. chlorideae parasitism was more than 18 h. and it never dominated the interactions, when it was the second one to parasitise. This implied that C. chlorideae had an almost consistent advantage over E. argenteopilosus. In the mass exposure experiment, the two parasitoid species (either alone or together) were allowed to forage and parasitise the host larvae in cages. When the two parasitoid species were allowed to forage in the same host patch simultaneously, the performance of C. chlorideae when it was alone was statistically similar to its performance in the presence of E. argenteopilosus. However, E. argenteopilosus performed better when it could forage alone. The results of both experiments revealed that C. chlorideae was the more competitive of the two species.     

Role of proline and leaf expansion rate in the recovery of stressed white clover leaves with increased phosphorus concentration

Osmotic adjustment (OA) and increased cell-wall extensibility required for expansive leaf growth are well defined components of adaptation to water stress in dry soil, which might interact with soil phosphorus (P) concentration and defoliation frequency for intensively grazed white clover in legume-based pastures. Experiments were conducted with frequently and infrequently defoliated mini-swards of white clover growing in dry soil with low and high P concentrations. The higher yielding high-P plants were able to dry the soil to greater soil water suctions; their leaves had lower water potential values, yet they showed fewer water stress symptoms and underwent a more complete recovery from the water stress symptoms on rewatering, than the low-P plants. High- P plants had greater OA, proline concentration and leaf expansion rate. On the other hand, low-P plants showed an increased osmotic concentration when there was no change in the total solute content per unit of leaf d. wt, indicating more loss of water from the leaf tissue. The key measures that appeared to be directly associated with plant recovery over a short period following water stress were increased proline concentration and leaf expansion rate, probably resulting from increased cell-wall extensibility rather than increased production of cells for the high-P plants.     

应用生物信息学的系统化综合性教学改革实践

信息时代由于信息量巨大,传统的生物学讲学模式易导致知识片段化和浅表化等问题,从而显得乏味。应用生物信息学由于具有在实践中串并联相关知识点的特征,可成为转变这些问题的重要利器。为利用好这把利器,本文探讨了应用生物信息学课程的系统化综合性教学改革。论文从教学内容系统性布局(课程定位、内容结构和教学手段)和综合解析优秀科普视频中趣味性生物学问题两方面,图文并茂地展示了改革实践。实践中学生们受益匪浅。学生综合素质的提升体现在很多方面,比如认知的系统性与深度提高、思维模式由被动转变为主动、团队合作意识增强、学习兴趣热情提升、克服困难的勇气与自信心增强、自主设计与创新能力提升等。信息时代的生命科学已由传统的实验性科学转变为由思维分析主导的实验设计兼由设计主导的实验论证性科学,而应用生物信息学课程正是训练信息时代相关科研能力的重要环节。论文实施的系统化综合性教学改革取得了一定成效,值得借鉴与交流。     

Effect of water stress on the enzymes of nitrogen metabolism in mung bean (Vigna radiata Wilczeck) nodules

Abstract. Water stress created by withholding irrigation in mung bean resulted in decreased leaf water potential and nodule moisture content. Decreased leaf water potential was associated with decreased activity of nitrogenase, glutamine synthetase (GS), asparagine synthetase (AS), aspartate amino transferase (AAT), xanthine dehydrogenase (XDH) and uricase. However, the activity of glutamate dehydrogenase increased three-fold under severe stress. The activity of allantoinase and allantoicase was not affected by moderate stress but decreased under severe stress. The in vitro production of allantoic acid from allantoin and uric acid in the cytosol fraction decreased more than its production from xanthine and hypoxanthine. The production of NADH also decreased under stress.
During recovery from severe stress, the activity of XDH and uricase further decreased, whilst that of allantoinase and allantoicase increased compared to the control. This corresponded with the higher content of ureides during recovery. The recovery in other enzymes was not complete although leaf water potential and nodule moisture content recovered fully within 24 h.     

Transthoracic fine needle aspiration cytology of lung for suspected malignancy: an audit of cytological findings with histopathological correlation

Transthoracic fine needle aspiration cytology (TFNAC) is an invasive procedure and should therefore be subject to regular review. We report an audit of TFNAC from 146 patients. One hundred and thirty‐six samples (93%) were adequate and 86 were malignant, 16 suspicious and 34 contained no malignant cells. TFNAC was the sole means of diagnosis of malignancy in 55 patients. However, further pathological data were available in 58 of the adequate samples; TFNAC was malignant in 31, suspicious in eight and contained no malignant cells in 19. All malignant TFNAC were confirmed (absolute sensitivity=85%; positive predictive value=100%); as were five of eight with suspicious cytology. Of 19 patients with negative TFNAC, nine were subsequently found to have a malignancy (specificity=68%).