Fitness costs associated with resistance to insecticides have been well documented, usually at normal temperature conditions, in many insect species. In this study, using chlorpyrifos-resistant homozygote (RR) and chlorpyrifos-susceptible homozygote (SS) of resistance ace1 allele of Plutella xylostella (DBM), we confirmed firstly that high temperature experience in pupal stage influenced phenotype of wing venation in insecticide-resistant and insecticide-susceptible Plutella xylostella, and SS DBM showed significantly higher thermal tolerance and lower damages of wing veins under heat stress than RR DBM. As compared to SS DBM, RR DBM displayed significantly lower AChE sensitivity to chlorpyrifos, higher basal GSTs activity and P450 production at 25°C, but higher inhibitions on the enzyme activities and P450 production as well as reduced resistance to chlorpyrifos under heat stress. Furthermore, RR DBM displayed significantly higher basal expressions of hsp69s, hsp72s, hsp20,hsp90,Apaf-1, and caspase-7 at 25°C, but lower induced expressions of hsps and higher induced expressions of Apaf-1,caspase-9, and caspase-7 under heat stress. These results suggest that fitness costs of chlorpyrifos resistance in DBM may partly attribute to excess consumption of energy caused by over production of detoxification enzymes and hsps when the proteins are less demanded at conducive environments but reduced expressions when they are highly demanded by the insects to combat environmental stresses, or to excess expressions of apoptotic genes under heat stress, which results in higher apoptosis. The evolutionary and ecological implications of these findings at global warming are discussed.

Hormesis induced by insecticides at the dosage lower than what ostensibly directly causes death on insects was studied. This paper reports the effects of the in vivo application of varied concentrations of chlorpyrifos (CPF) on Plutella xylostella (DBM). The insecticide concentrations applied included 0.000025-2.5 mg l-1, which are far lower than LC1 (7.2 mg l-1), for the CPF-susceptable (Si) DBM, and 250 mg l-1 which is far below LC1 (1286 mg l-1), for the CPF-resistant (Rc) DBM, as well as LC10- and LC50-doses for both strains. Significant hormesis was found with the 'hermetic-CPFs', i.e., 0.0025 mg l-1 for Si DBM and 2.5 mg l-1 for Rc DBM, at the normal or high temperature either in a 24 h or under a long-term treatment. These doses of CPF significantly stimulated the development and increased the fecundity of Si and Rc DBM at 25°C with approximately 23.5-29.8% activity increase on acetylcholinesterase (AChE) and 30.5-91.3% increase on glutathione S-transferases (GSTs) at 25 or 38°C in 4-24 h. The enzymatic activities were significantly reduced by LC50-CPF at 25°C in vivo, but the inhibition was relieved significantly, if the insects were first subjected to a hormetic-CPF pretreatment. It was remarkable that the average rates of enzymatic activity increase were 67.5-76.6% for AChE and 366-546% for GSTs. Consequently, it was concluded that the hormesis on Si and Rc DBM could be induced by CPF doses far below LC1 at normal or high temperature in short- or long-term treatment. These findings might help to improve the current insect control practices in the field.

To study the component and gene expressions of apoptosome in the mitochondrial-associated apoptotic pathway, cytochrome c and Apaf-1 were identified in the diamondback moth (DBM), Plutella xylostella, collected from Fuzhou, China. The full-length cDNA of cytochrome c comprised 873 bp, including a 327 bp ORF encoding a putative protein of 108 amino acids. Two full-length cDNAs of Apaf-1, Apaf-1a and Apaf-1b, were identified. Apaf-1a shared the same region of 5'-UTR (5'-untranslated region) (172 bp) and ORF (4,647 bp) of cDNA, but was 73 bp longer than Apaf-1b in the region of 3'-UTR of the cDNA. The ORF of Apaf-1a and Apaf-1b encoded a putative protein of 1,548 amino acids and shared 100% identity. No significant up-regulation of cytochrome c mRNA expression was found in both the chlorpyrifos-resistant (R R) and chlorpyrifos-susceptible (S S) DBM. Compared with the control (at 25°C for 3 h), mRNA transcript levels of Apaf-1a and Apaf-1b increased with the increase of temperature and were significantly higher at 37, 42, 47 and 50°C than at 25 and 33.5°C in R R DBM. However, the extent of up-regulation expression of Apaf-1a and Apaf-1b in S S DBM was slight under heat stress except at 42°C. In general, significantly higher increase in the mRNA transcript level of Apaf-1a and Apaf-1b was found in R R DBM than in S S DBM. It has been suggested that significantly higher expression of caspase-7 and lower biological fitness occurs in R R DBM under heat stress, a suggestion confirmed in our previous publications, and a result which might be associated with their higher up-regulation expression of Apaf-1a and Apaf-1b.

NAT (Network Address Translation) is the process of transforming one IP address in the datagram header into another. In practical applications, NAT is mainly used to realize the function of the access of private network to public network. The method of using a small number of public IP addresses representing a large quantity of private IP addresses will help to slow down the depletion of the IP address space available. As the Network Architecture is becoming more complex, the way, under such context, the NAT technology functions is of great importance. This dissertation will mainly analyze the special treatment of NAT in the following aspects like unified address management ,the priority level of address pool ,NAT mapping in PING Operation ,the treatment of ICMP err packet ,the NAT transformation of fragmented packet as well as the infinitive connection of multi –core products.