Performance of Sclerodermus brevicornis,a parasitoid of invasive longhorn beetles,when reared on rice moth larvae

Biological control efficiency can be improved by developing effective mass‐rearing systems to produce large numbers of high‐quality parasitoids. This study explored an alternative host for rearing Sclerodermus brevicornis (Kieffer) (Hymenoptera: Bethylidae), a potential biocontrol agent for the suppression of exotic and invasive wood‐boring longhorn beetle (Coleoptera: Cerambycidae) populations in the European agroforestry ecosystems. We tested larvae of the rice moth, Corcyra cephalonica Stainton (Lepidoptera: Pyralidae), as host for the parasitoid. We quantified the probability and timing of host attack and parasitism as well as reproductive success, offspring production, and the characteristics of adult offspring. As S. brevicornis is a quasi‐social species (multiple females, communally produced offspring broods), we also explored the effects of varying the number of females to which individual hosts were presented, with the aim of determining the optimal female‐to‐host ratio. As time to host attack can be a limiting factor in S. brevicornis rearing protocols, we tested the use of adult females of another bethylid species, Goniozus legneri Gordh, to paralyse C. cephalonica larvae prior to presentation. We identified the conditions within our experiment that maximized offspring production per host and offspring production per adult female parasitoid. We found that C. cephalonica is suitable as a factitious host and, as it is considerably more straightforward for laboratory rearing than cerambycid species, it is a good candidate for adoption by future S. brevicornis mass‐rearing and release programmes.     

植物-固定化菌剂联合修复多环芳烃污染土壤

以火凤凰根际土壤中发现的3种优势菌[分枝杆菌(Ⅰ)、产黄纤维单胞菌(Ⅱ)、少动鞘氨醇单胞菌(Ⅲ)]构建的多菌剂体系为供试菌剂,针对大港油田原油污染土壤,将固定化供试菌剂接种于修复植物火凤凰根际,探讨供试菌剂强化火凤凰修复多环芳烃(PAHs)污染土壤的效果。结果表明: 处理ⅠⅢ(有效活菌数为10⁹ cfu·mL^-1)和ⅠⅡⅢ(有效活菌数为10⁷ cfu·mL^-1)对PAHs的降解有促进作用,PAHs降解率分别为32.2%和41.4%,均显著高于相应对照处理。此外,处理ⅠⅡⅢ对火凤凰的地下生物量有明显促进作用,比对照处理增加了31.2%。表明由3种优势菌构建的多菌剂ⅠⅡⅢ可以作为火凤凰修复PAHs污染土壤的强化手段,为微生物强化植物修复技术提供了新的修复思路及方法。     

Therapeutic applications of lysostaphin against Staphylococcus aureus

Staphylococcus aureus, an opportunistic pathogen, causes diverse community and nosocomial-acquired human infections, including folliculitis, impetigo, sepsis, septic arthritis, endocarditis, osteomyelitis, implant-associated biofilm infections and contagious mastitis in cattle. In recent days, both methicillin-sensitive and methicillin-resistant S. aureus infections have increased. Highly effective anti-staphylococcal agents are urgently required. Lysostaphin is a 27 kDa zinc metallo antimicrobial lytic enzyme that is produced by Staphylococcus simulans biovar staphylolyticus and was first discovered in the 1960s. Lysostaphin is highly active against S. aureus strains irrespective of their drug-resistant patterns with a minimum inhibitory concentration of ranges between 0·001 and 0·064 μg ml⁻¹. Lysostaphin has activity against both dividing and non-dividing S. aureus cells; and can seep through the extracellular matrix to kill the biofilm embedded S. aureus. In spite of having excellent anti-staphylococcal activity, its clinical application is hindered because of its immunogenicity and reduced bio-availability. Extensive research with lysostaphin lead to the development of several engineered lysostaphin derivatives with reduced immunogenicity and increased serum half-life. Therapeutic efficacy of both native and engineered lysostaphin derivatives was studied by several research groups. This review provides an overview of the therapeutic applications of native and engineered lysostaphin derivatives developed to eradicate S. aureus infections.     

Changes in haemolymph parameters and insect ability to respond to immune challenge during overwintering

Overwintering is a challenging period in the life of temperate insects. A limited energy budget characteristic of this period can result in reduced investment in immune system. Here, we investigated selected physiological and immunological parameters in laboratory‐reared and field‐collected harlequin ladybirds (Harmonia axyridis). For laboratory‐reared beetles, we focused on the effects of winter temperature regime (cold, average, or warm winter) on total haemocyte concentration aiming to investigate potential effects of ongoing climate change on immune system in overwintering insects. We recorded strong reduction in haemocyte concentration during winter; however, there were only limited effects of winter temperature regime on changes in haemocyte concentration in the course of overwintering. For field‐collected beetles, we measured additional parameters, specifically: total protein concentration, antimicrobial activity against Escherichia coli, and haemocyte concentration before and after overwintering. The field experiment did not investigate effects of winter temperature, but focused on changes in inducibility of insect immune system during overwintering, that is, measured parameters were compared between naïve beetles and those challenged by Escherichia coli. Haemocyte concentration decreased during overwintering, but only in individuals challenged by Escherichia coli. Prior to overwintering, the challenged beetles had a significantly higher haemocyte concentration compared to naïve beetles, whereas no difference was observed after overwintering. A similar pattern was observed also for antimicrobial activity against Escherichia coli as challenged beetles outperformed naïve beetles before overwintering, but not after winter. In both sexes, total protein concentration increased in the course of overwintering, but females had a significantly higher total protein concentration in their hemolymph compared to males. In general, our results revealed that insect’s ability to respond to an immune challenge is significantly reduced in the course of overwintering.     

Investigating the bioactivity of cells and cell-free extracts of Streptomyces griseus towards Fusarium oxysporum f. sp. cubense race 4

The antifungal activity of viable cells of Streptomyces griseus (St 4) and its cell-free extracts were investigated against the pathogenic Fusarium oxysporum f. sp. cubense race 4 (FOC race 4), causal agent of wilt disease in bananas. Results from in vitro and soil assays showed cells and cell-free extracts of S. griseus were able to inhibit FOC race 4 with varying degree of success. Antifungal activity was attributed to chitinase and β-1,3-glucanase, detected in both cells and cell-free extracts, which caused lysis of fungal cell wall and inhibited sporulation. Interestingly, β-1,3-glucanase and chitinase activities were significantly higher in cell-free extracts compared to cells, with 8.30 and 5.43 against 7.96 and 4.95 U mL⁻¹, respectively. Application to soil however, showed inoculation using S. griseus cells were more effective in suppressing growth of FOC race 4 than crude extracts, with 6 log₁₀ CFU of FOC race 4 g⁻¹ soil enumerated compared to 7 log₁₀ CFU of FOC race 4 g⁻¹ soil after 20 days. To summarize, this study has shown that cell-free extracts of S. griseus have antifungal properties but may not be suitable for soil application in its current form (liquid suspension). Further investigations on bioformulation may address this limitation.     

The use of dyes in modern biomedicine

The discovery of the aniline dyes in the 19th century and contemporary investigation of their use as biological stains by scientists such as Koch and Ehrlich led to the idea of selectivity and formed the basis of modern chemotherapy; several of these dyes remain in pharmacopoeias. While the development of therapeutics has tended to avoid colored compounds due to unwanted coloration, the modern application of photosensitizing dyes, both in the fields of cancer therapy and anti-infection, depends on this phenomenon. In addition, the fluorescence of some anticancer photosensitizers allows their use as tumor localizing agents, which is particularly useful in precancerous conditions. It is also fitting that dyes employed in Ehrlich's original studies, such as the phenothiazinium dye, methylene blue, are now in clinical use for disinfecting donated blood products.     

Computer-Intensive Statistical Procedures

The overall goal of this review is to summarize the current body of knowledge about the structure and function of major proteins of Bacillus anthracis and/or similar spore-forming organisms. B. anthracis is a key spore-forming biological threat agent, as well as human and animal Gram-positive bacterial pathogen. The structural information described here is limited to approximately the last 5 years. This information is then related to the role of the selected proteins in pathogenesis and in the possible development of novel vaccine and/or other antimicrobial agents against spore-forming organisms, including anthrax, a disease caused by B. anthracis.

Among spore-forming bacteria, Bacillus and Clostridium species are the predominant spore-forming bacilli that cause serious diseases. The biochemical properties and mechanism of catalysis of the novel spore germination protease that degrades small, acid-soluble proteins protecting DNA against damage, a cofactor independent phosphoglycerate mutase, NAD⁺ synthetase, and the three know B. anthracis toxins, protective antigen, lethal factor, and edema factor are described. The studies described in this work review and unify selected information critical for the prevention of microbial diseases such as anthrax. A strategy for the structure-guided development of new prophylactic and therapeutic agents is discussed.     

DNA staining in agarose and polyacrylamide gels by methyl green

ABSTRACT

Methyl green (MG) is an inexpensive, nonproprietary, traditional histological stain for cell nuclei. When bound to DNA and upon excitation with orange-red light, it fluoresces brightly in the far red region. We compared MG with ethidium bromide (EtBr), the conventional stain for DNA in gels, and Serva DNA stain G? (SDsG), a proprietary stain marketed as a safer alternative to EtBr for staining of electrophoresed DNA bands in agarose and polyacrylamide gels. DNA-MG fluorescence was recorded and 2.4 μg/ml MG produced crisp images of electrophoresed DNA after incubation for 10 min. Stain solutions were stable and detection limits for faint bands as well as relative densitometric quantitation were equivalent to EtBr. MG, EtBr and SDsG cost 0.0192, 0.024 and 157.5 US cents/test, respectively. MG is an effective stain for visualizing DNA in agarose and polyacrylamide gels. Its major advantages including low cost, comparable quality of staining, storage at room temperature, photo-resistance and low mutagenic profile outweigh its disadvantages such as staining of tracking dye and requirement for a gel documentation system with a red filter.     

Peptide inhibitors against herpes simplex virus infections

Herpes simplex virus (HSV) is a significant human pathogen causing mucocutaneous lesions primarily in the oral or genital mucosa. Although acyclovir (ACV) and related nucleoside analogs provide successful treatment, HSV remains highly prevalent worldwide and is a major cofactor for the spread of human immunodeficiency virus. Encephalitis, meningitis, and blinding keratitis are among the most severe diseases caused by HSV. ACV resistance poses an important problem for immunocompromised patients and highlights the need for new safe and effective agents; therefore, the development of novel strategies to eradicate HSV is a global public health priority. Despite the continued global epidemic of HSV and extensive research, there have been few major breakthroughs in the treatment or prevention of the virus since the introduction of ACV in the 1980s. A therapeutic strategy at the moment not fully addressed is the use of small peptide molecules. These can be either modeled on viral proteins or derived from antimicrobial peptides. Any peptide that interrupts protein–protein or viral protein–host cell membrane interactions is potentially a novel antiviral drug and may be a useful tool for elucidating the mechanisms of viral entry. This review summarizes current knowledge and strategies in the development of synthetic and natural peptides to inhibit HSV infectivity. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.     

Structural and functional characterization of peptides derived from the carboxy‐terminal region of a defensin from the tick Ornithodoros savignyi

Tick defensins may serve as templates for the development of multifunctional peptides. The purpose of this study was to evaluate shorter peptides derived from tick defensin isoform 2 (OsDef2) in terms of their antibacterial, antioxidant, and cytotoxic activities. We compared the structural and functional properties of a synthetic peptide derived from the carboxy‐terminal of the parent peptide (Os) to that of an analogue in which the three cysteine residues were omitted (Os–C). Here, we report that both peptides were bactericidal (MBC values ranging from 0.94–15 µg/ml) to both Gram‐positive and Gram‐negative bacteria, whereas the parent peptide only exhibited Gram‐positive antibacterial activity. The Os peptide was found to be two‐fold more active than Os–C against three of the four tested bacteria but equally active against Staphylococcus aureus. Os showed rapid killing kinetics against both Escherichia coli and Bacillus subtilis, whereas Os–C took longer, suggesting different modes of action. Scanning electron microscopy showed that in contrast to melittin for which blebbing of bacterial surfaces was observed, cells exposed to either peptide appeared flattened and empty. Circular dichroism data indicated that in a membrane‐mimicking environment, the cysteine‐containing peptide has a higher α‐helical content. Both peptides were found to be non‐toxic to mammalian cells. Moreover, the peptides displayed potent antioxidant activity and were 12 times more active than melittin. Multifunctional peptides hold potential for a wide range of clinical applications and further investigation into their mode of antibacterial and antioxidant properties is therefore warranted. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.