In vitro production of the biological control agent Heterorhabditis indica SL0708 in different agar media

ABSTRACT

Heterorhabditis indica SL0708 is an entomopathogenic nematode isolated from Valle del Cauca-Colombia, whose bacterial symbiont, Photorhabdus luminescens subsp. akhurstii SL0708, has potential to control pests of economic importance in Colombia. Since in vivo production does not supply its demand, this investigation evaluated H. indica SL0708 production on different agar media. Five culture media (I, II, III, IV and V) were evaluated for productivity and pathogenicity of infective juveniles (IJs). IJs emerged between 11 and 16 days after inoculation in all media, with a total of 2.7?×?10⁴ and 4.7?×?10⁶ IJs produced during 15 days after IJs emergence, with maximum productivity at day five and high variability. Pathogenicity to Galleria mellonella larvae was not significantly different between in vitro and in vivo produced IJs on all media tested. Media IV and V were selected for their higher productivity. Subsequently, nematode inoculum size was evaluated in selected media at 2000, 4000 and 6000?IJs ml^?1, but significant differences were not observed in productivity and pathogenicity. Lastly, lipid source influence was evaluated in medium IV comparing canola, olive and soy oils. None of the plant-based oils had a significant effect on IJs production and pathogenicity. A medium was selected for H. indica SL0708 IJs production which was suitable in terms of productivity, culture time and pathogenicity of IJs produced. The medium and parameters selected in this study could be applied as an alternative for mass production of this entomopathogenic nematodes.     

Surgical treatment of transcatheter aortic valve infective endocarditis

Netherlands Heart Journal - There is growing interest in infections occurring after transcatheter aortic valve implantation (TAVI). The incidence, and clinical and anatomical features suggest many...     

手术治疗先天性心脏病患者活动期心内膜炎的相关因素

目的:确定先天性心脏病活动期感染性心内膜炎(active infective endocarditis,AIE)的手术指征。方法:于2003-2011年从71个机构数据库中调查并采集247例患有感染性心内膜炎的儿童及成人先天性心脏病(congenital heart disease,CHD)患者数据,其中74例(30%)进行了AIE手术治疗。回顾性分析患者的年龄、性别、感染心内膜炎前对CHD的诊断、致病微生物和感染部位等数据。结果:与AIE手术治疗必要性显著相关的指标是感染性心内膜炎(infective endocarditis,IE)病发前对心脏异常的诊断缺乏、主动脉瓣IE、瓣周脓肿、心力衰竭以及抗生素发生变化。逐步逻辑回归方程分析结果表明瓣周脓肿、心力衰竭以及抗生素改变是先天性心脏病患者进行AIE手术治疗必要性的独立决定因素。结论:对IE合并CHD的患者而言,当心力衰竭、瓣周脓肿或抗生素变化发生时,手术可作为治疗AIE的一种手段。     

Brugia malayi: comparison of protective immune responses induced by Bm-alt-2 DNA, recombinant Bm-ALT-2 protein and prime-boost vaccine regimens in a jird model

Immunization of jirds with Bm-alt-2 elicited partial protection against challenge infection with the filarial parasite Brugia malayi. In this study, we initially compared the protective immune responses elicited following immunization with recombinant Bm-ALT-2 protein regimen and Bm-alt-2 DNA regimen. These studies showed that protein vaccination conferred approximately 75% protection compared to DNA vaccination that conferred only 57% protection. Analysis of the protective immune responses showed that the protein immunization promoted a Th2-biased response with an increase in IL-4, IL-5 and IgG1 responses, whereas, the DNA vaccine promoted a Th1-biased response with profound IFN-gamma and IgG2a responses. Since protein vaccination gave better results than DNA vaccination, we then wanted to evaluate whether a prime-boost vaccination that combined DNA prime and protein boost will significantly increase the protective responses induced by the protein vaccine. Our results suggest that prime-boost vaccination had no added advantage and was comparatively less effective (64% protection) than the Bm-ALT-2 protein alone vaccination. Prime boost vaccination generated mixed Th1/Th2 responses with a slightly diminished Th2 responses compared to protein vaccination. Thus, our results suggest that Bm-ALT-2 protein vaccination regimen may be slightly better than prime-boost vaccine regimen and the mechanism of protection appears to be largely mediated by a Th2-biased response.     

Trichinella spiralis: effect of high temperature on infectivity in pork

Twenty gram samples of homogenized Boston shoulder from swine experimentally infected with Trichinella spiralis were sealed in plastic pouches, pressed to a uniform thickness of 2 mm, and subjected to water bath temperatures of 49, 52, 55, 60, and 63 +/- 0.5 C for intervals of 2 min to 6 hr, especially within the interval of 0 to 15 min. These times included a period of about 1 min at the start and a period of about 1 min at the end for temperature equilibration. Treated samples were rapidly chilled to 25 C and then digested in a 1% pepsin-HCl solution at 37 C for 18 hr to recover T. spiralis larvae. The recovered larvae were suspended in 2 ml saline; 1 ml of this suspension was introduced into the stomach of each of two rats. The linear equation, log (time) = 17.3 -0.302 (temperature), was calculated from the time required at each temperature for the inactivation of T. spiralis larvae. The correlation coefficient for that relationship was r = -0.994. Larvae heated in the meat to 55 C for 4 min retained their infectivity, but were rendered noninfective after 6 min at 55 C. At 60 C, larvae were not infective after only 2 min (zero dwell time); whereas at 52 C, 47 min were required to render the larvae noninfective. Larvae in meat heated to 49 C were infective after 5 hr but not after 6 hr. These data demonstrate that the destruction of infectivity of T. spiralis is time-temperature related.     

联合应用生态制剂治疗感染性腹泻的临床研究

本文应用丽珠肠乐加整肠生联合治疗感染性腹泻,治愈率为９２．１％,与单一应用整肠生,治愈率（７３．１％）有显著性差异（ｘ￣２＝４．２４,Ｐ＜０．０５）,与氟哌酸组无明显差异（ｘ￣２＝３．０２,Ｐ＞０．０５）,单一整肠生组与氟哌酸组无明显差异（ｘ￣２＝０．２２,Ｐ＞０．０５）。生态制剂有良好确切疗效,两种生态制剂联合治疗,明显提高治愈率。感染性腹泻原因菌的分离结果,揭示了本地区感染性腹泻病原菌的多样化和复杂性,应用生态制剂联合治疗,优于抗生素治疗。     

The second messenger cyclic GMP mediates activation in Ancylostoma caninum infective larvae

The developmentally arrested infective larva (L(3)) of hookworms encounters a host-specific signal during infection that initiates previously suspended developmental pathways. Activated L(3) express a parasitic gene set that encodes proteins involved in moulting, growth and development to the adult stage. Early events in this activation to parasitism can be investigated using an in vitro larval feeding assay. When Ancylostoma caninum L(3) are exposed to a host-like stimulus, they resume feeding and release molecules involved in infection. The dauer larva of the free-living nematode Caenorhabditis elegans is a developmentally arrested stage analogous to the hookworm L(3). Recovery from the dauer stage has been proposed as a model for the transition to parasitism in hookworm. Dauer formation and recovery involve several tightly regulated pathways, including a cyclic GMP mediated signalling pathway. To determine if hookworm L(3) activation uses a similar pathway, 8-bromo-cyclic GMP, a membrane permeant analogue of cyclic GMP, was tested for its ability to stimulate feeding. Populations of L(3) incubated with 0.5 mM 8-bromo-cyclic GMP began feeding, and reached maximum feeding at 3.5-5.0 mM. Unlike the serum stimulus, which triggers feeding after a short exposure, 8-bromo-cyclic GMP must be present throughout the entire incubation. Both serum stimulated and 8-bromo-cyclic GMP stimulated L(3) secreted Ancylostoma secreted protein 1, indicating that the stimuli activate the same pathway. Serum and 8-bromo-cyclic GMP stimulated feeding was inhibited by atropine, a muscarinic receptor antagonist. However, only serum stimulated feeding was inhibited by 4,7-phenanthroline, a non-chelating isomer of the metalloprotease inhibitor 1,10-phenantholine. The results indicate that cyclic GMP mediates activation in hookworm larvae, and that a muscarinic receptor is involved in activation. This also suggests that hookworm activation and dauer recovery share similar signalling pathways, and that C. elegans dauer recovery can be used as a model for the transition to parasitism in hookworms.     

长爪沙鼠的肝毛细线虫感染率与鼠类及猛禽密度的关系

为研究鼠类密度和猛禽密度对鼠类肝毛细线虫(Capillaria hepatica)感染率的影响,作者于2004年7月在内蒙古锡林郭勒盟阿巴嘎旗北部和东乌珠穆沁旗西南部典型草原草场选取了14个实验样地,采用洞口计数法(四分之一圆面积法)调查估计各实验样地内长爪沙鼠(Meriones unguiculatus)密度,同时采用夹线调查法捕获鼠类样本,进行常规解剖获取肝毛细线虫的感染数据。采用目测计数法统计猛禽的出现频次,并以其出现频次作为猛禽的相对密度指标。实验样地共捕获长爪沙鼠1 058只,观察到鹰隼类活动69只次。数据分析结果表明,长爪沙鼠肝毛细线虫感染率与鼠类密度之间存在极显著的正相关关系(P0.01,R~2=0.926),长爪沙鼠肝毛细线虫感染率与猛禽密度之间亦存在极显著的正相关关系(P0.01,R~2=0.853)。该结果说明,长爪沙鼠是肝毛细线虫的主要宿主,鼠类密度和猛禽密度的升高均会增加长爪沙鼠肝毛细线虫感染率,猛禽密度和鼠类密度之间还存在叠加效应,猛禽的捕食作用会加快肝毛细线虫病的传播周期,加重肝毛细线虫病疫情。     

Identification of phytoconstituents from Albizia lebbeck as potential therapeutics against HIV-1 reverse transcriptase associated with infective endocarditis: In silico and in vitro approaches

Acquired immune deficiency syndrome (AIDS) is an unadorned disease affected via the human immunodeficiency virus (HIV), which has become the most infectious diseases worldwide. HIV-1 RT has been shown to be present in the cardiac tissue of patients with HIV-associated infective endocarditis, and to be associated with the development of valvular lesions and other cardiac abnormalities. The use of anti-retroviral therapies has helped to control the virus and reduce the incidence of HIV-1 associated infective endocarditis. Though, these treatments have several adjacent effects, and the improvement of drug-resistant stresses of the virus has become a significant challenge in HIV treatment. This study is to identify A. lebbeck phytoconstituents with HIV-1 RT inhibitory activity for potential therapeutic use against HIV-1 RT associated with infective endocarditis. We performed in silico and in vitro screening of natural cardiovascular phytoconstituents from Albizia lebbeck, a medicinal plant that has been traditionally used for the management of numerous diseases. The in silico results showed that all three compounds (geraldone, luteolin, and isookanin) exhibited affinities of solid binidng to the active amino acids of HIV-1 RT's DNA-polymerase (DNA-p) and Ribonuclease-H (RNA-H) active positions, suggesting their potential as HIV-1 RT inhibitors. In vitro assessment of the three compounds at a concentration of 1 mg/mL revealed that Geraldone exhibited the most effective inhibitory consequence on HIV-1 RT activity (83.45%), followed by Isookanin (75.88%) and Luteolin (66.36%). These findings suggest that these compounds have the potential to inhibit HIV-1 RT associated with infective endocarditis and could assist as main compounds for emerging unique anti-HIV-1 agents. Further studies are needed to confirm the in vitro and in vivo efficacy of these molecules and assess their safety and efficiency as anti-HIV-1 drugs.     

Structural explanation for the effect of humidity on persistence of airborne virus: Seasonality of influenza

Seasonal variation of infectious diseases is one of the oldest observations in epidemiology, most particularly for Influenza and other respiratory viral infections. The reason for this seasonality is poorly understood, despite the profound importance of these infections as communicable diseases capable of causing global epidemics. Environmental factors including relative humidity, vapor pressure and temperature are known to affect seasonal virus survival and transmission. Immunological status of the host and evolution of the virus have also been proposed to be the reason behind the cyclic recurrence. The molecular basis of these effects or their interplay with biological factors has not been reported before. Here a theoretical analysis shows that the structure of the viral envelope determines its persistence and transmission in various environmental conditions. Physico-chemical properties of the virus particles and their interaction with atmospheric processes along with the availability and susceptibility of hosts generates the conspicuous seasonality prevalent in the temperate zones and the apparent lack of it in the tropics. Additionally this model can estimate virus transmission in different weather conditions. This model may help to determine the right actions effective in preventing outbreaks of the flu-like respiratory viruses.