Global distribution and invasion pattern of oriental fruit fly,Bactrocera dorsalis (Diptera: Tephritidae)

Since the start of the 20th century, many invasive alien species (IAS) have spread rapidly around the world, causing serious threats to economies, societies and the environment. Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is an important quarantine insect species in many countries that spread around the world over the last century. This review collected information on the distribution of B. dorsalis to explore the patterns of its invasion expansion. We found B. dorsalis to be distributed in 75 countries (comprised of 124 geographical distribution regions: provinces or states) in Asia, Africa, North America, South America and Oceania up to 2017. Asia and Africa were the most represented regions, accounting for 86.3% of the total number of countries. From 1910 to 1990, B. dorsalis was only found in five countries, but in the last three decades, it has experienced a sharp increase in its rate of spread, invading 70 more countries. Global temperature anomaly has significantly positive correlation with the spread of B. dorsalis. The results of this review provide a theoretical basis for understanding and predicting the continued spread of B. dorsalis under global changes.     

铜绿假单胞菌对青霉素类抗生素异质性耐药研究

【背景】铜绿假单胞菌是临床上常见的条件致病菌,其异质性耐药的发生常导致临床治疗失败。【目的】研究铜绿假单胞菌对青霉素类抗生素的异质性耐药情况,为相关临床感染治疗提供一定的依据。【方法】收集临床分离的50株铜绿假单胞菌,采用纸片扩散法(diskdiffusion method)即Kirby-Bauer (K-B)法、菌落谱型分析(population analysis profile,PAP)法、生长实验以及传代稳定性实验探究铜绿假单胞菌的异质性耐药特征。【结果】K-B法初筛得到铜绿假单胞菌对哌拉西林(piperacillin,PIP)、哌拉西林/他唑巴坦(piperacillin/tazobactam,TZP)和替卡西林/克拉维酸(ticarcillin/clavulanic acid,TIM)的异质性耐药率分别为52%、52%和54%。PAP实验确认后有13株异质性耐药菌,其检出率占总实验菌株的26%。随机选取8株异质性耐药菌株,其耐药亚群的发生频率为7.3×10-7-1.2×10-5。通过无抗生素压力的生长实验发现,异质性耐药菌株PAS92、PAS57与其各自的3株最高PIP浓度平...     

The influences of PRG-1 on the expression of small RNAs and mRNAs

Background

In metazoans, Piwi-related Argonaute proteins play important roles in maintaining germline integrity and fertility and have been linked to a class of germline-enriched small RNAs termed piRNAs. Caenorhabditis elegans encodes two Piwi family proteins called PRG-1 and PRG-2, and PRG-1 interacts with the C. elegans piRNAs (21U-RNAs). Previous studies found that mutation of prg-1 causes a marked reduction in the expression of 21U-RNAs, temperature-sensitive defects in fertility and other phenotypic defects.

Results

In this study, we wanted to systematically demonstrate the function of PRG-1 in the regulation of small RNAs and their targets. By analyzing small RNAs and mRNAs with and without a mutation in prg-1 during C. elegans development, we demonstrated that (1) mutation of prg-1 leads to a decrease in the expression of 21U-RNAs, and causes 35 ~ 40% of miRNAs to be down-regulated; (2) in C. elegans, approximately 3% (6% in L4) of protein-coding genes are differentially expressed after mutating prg-1, and 60 ~ 70% of these substantially altered protein-coding genes are up-regulated; (3) the target genes of the down-regulated miRNAs and the candidate target genes of the down-regulated 21U-RNAs are enriched in the up-regulated protein-coding genes; and (4) PRG-1 regulates protein-coding genes by down-regulating small RNAs (miRNAs and 21U-RNAs) that target genes that participate in the development of C. elegans.

Conclusions

In prg-1-mutated C. elegans, the expression of miRNAs and 21U-RNAs was reduced, and the protein-coding targets, which were associated with the development of C. elegans, were up-regulated. This may be the mechanism underlying PRG-1 function.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-321) contains supplementary material, which is available to authorized users.     

Intentionally introduced species: more easily invited than removed

Alien species are brought into countries world wide on a massive scale for agricultural production, ex situ conservation, landscape aesthetics, gardens, and ecosystem restoration. Unfortunately, some of these species have escaped and adversely impacted on regional as well as global biodiversity conservation and agricultural production. To reduce such risks, it is necessary to implement specific and effective measures. Since various government departments and institutions are involved in the management of alien species, it is difficult to prevent native and agroecosystems from being invaded by invited species. We propose the establishment of a supervision and inspection continuum over intentional species introduction, similar to that which exists in some countries over unintentional species introductions. Namely, a justification of the necessity to import, a risk assessment, assurances as to provision of an adequate containment facility assessment, and a damage-limitation protocol should that need to be invoked. These requirements should be satisfied before an alien species is knowingly imported, and the necessary follow-up supervision is important post- importation.     

Multi-level assessment of ecological coastal restoration in South Texas

Adaptive management can be a very useful tool for assessing and improving coastal ecological engineering restoration projects. A shoreline restoration project using ecological engineering approaches to mitigate coastal erosion was developed and implemented in 2003 at Loyola Beach, Baffin Bay, TX. The project incorporated riprap, fiber matting, geotextile, and vegetation as an alternative to conventional hard structures for erosion control. As part of the restoration expansion, a detailed evaluation of the previous project was completed at several levels, including the landscape, geotechnical design, environmental and ecological considerations, and social and economic factors. The findings indicated that the vegetation and its underlying geotechnical integrity have played an important role in erosion mitigation. Overall the project was successful in the protection of the shoreline and was shown to be more ecologically beneficial than other hard structures. Based on the preliminary success of the initial project, the restoration techniques were adapted for another beach extension to the west. The assessment did reveal some weaknesses in the original project design including the need for more substantial toe protection and periodic maintenance requirements. Based on these assessments, some additional new methods for the restoration extension were proposed and implemented. The broader applicability of this restoration approach outside the local region has been presented through several outreach activities and delivered to coastal planners and land owners throughout the Texas Coastal Bend and Northern Mexico.     

Key genes and proteins involved in CTCM-reducing microvascular endothelial cell permeability induced by SLT-IIv using gene chips and DIGE

An Affymetrix mouse genome array and differential in-gel electrophoresis (DIGE) techniques were used to investigate the pharmacological mechanisms of a mixture of herbs, designated CTCM, a compound of traditional Chinese medicine, for the treatment of increased permeability in mouse intestinal microvascular endothelial cells (MIMECs) induced by the Shiga-like toxin type II variant (SLT-IIv). MIMECs were challenged with 10 μg/ml SLT-IIv for 12 h and then treated with CTCM at a concentration of 200 μg/ml for 12 h. Total RNA and proteins from each treatment group were extracted from cultured MIMECs for analysis by the Affymetrix GeneChip® Mouse Genome 430 2.0 microarray and DIGE. The results obtained demonstrated that there were one genes downregulated and one genes upregulated, one protein downregulated and four proteins upregulated in the SLT-IIv group compared to the control group. In the CTCM group, four genes were upregulated, three genes were downregulated, a single protein was downregulated and a single protein was upregulated when compared to the control group. When the CTCM-treated group was compared to the SLT-IIv group, expression of one gene was found to be increased, and all other genes were decreased, with five proteins downregulated. Analysis of the data suggested that CTCM specifically and effectively reduced microvascular endothelial cell permeability to SLT-IIv in the treatment of pig edema disease. In the CTCM-treated group, hspa9 expression was increased in both gene chip and DIGE analysis, so it may be a key protein in reducing cell permeability and utilized in medical treatments.     

Host shifts in economically significant fruit flies (Diptera: Tephritidae) with high degree of polyphagy

Insects tend to feed on related hosts. Coevolution tends to be dominated by interactions resulting from plant chemistry in defense strategies, and evolution of secondary metabolisms being in response to insect herbivory remains a classic explanation of coevolution. The present study examines whether evolutionary constraints existing in host associations of economically important fruit flies in the species‐rich tribe Dacini (Diptera: Tephritidae) and to what extent these species have evolved specialized dietary patterns. We found a strong effect of host phylogeny on associations on the 37 fruit flies tested, although the fruit fly species feeding on ripe commercially grown fruits that lost the toxic compounds after long‐term domestication are mostly polyphagous. We assessed the phylogenetic signal of host breadth across the fruit fly species, showing that the results were substantially different depending on partition levels. Further, we mapped main host family associations onto the fruit fly phylogeny and Cucurbitaceae has been inferred as the most likely ancestral host family for Dacini based on ancestral state reconstruction.