The potential for biological control of stoats (Mustela erminea)

Abstract

Accelerating the mortality of stoats (Mustela erminea) using biological agents, or reducing their fertility using chemosterilants or biological agents, are increasingly seen as more sustainable and more humane than trapping and poisoning. Obligate delayed implantation in fertilised female stoats of all ages allows 10–11 months for an applied biological agent or chemosterilant to interfere with gestation. Two chemosterilants (cabergoline and mifepristone) disrupt pregnancy in some species and may be effective on stoats, although they are not species‐specific and are probably more expensive than poisoning. For the longer term, more recent fertility control research has explored potentially more species‐specific options for other species based on inducing an immune response to an animal's own reproductive hormones, gametes, or products from embryos. Conception will be difficult to disrupt in stoats because females are sexually mature and are mated in the nest during a short period before they are weaned. A large research effort will be required to determine which of the immunosterilants being developed could be suitable candidates for stoat control. There are fewer options apparent for using biological agents to increase stoat mortality, although species‐specific strains of canine distemper virus may be effective against stoats.

The greatest impediment to controlling stoat fertility will be effective delivery of sterilants. For the foreseeable future, it will probably be necessary to rely on baits, but they are unlikely to put all target stoats at risk, and will be incapable of delivery over larger scales than at present.

Before undertaking expensive field trials and development of anti‐fertility and biological agents, the effects of putative compensatory changes in demographics that may be associated with changes in stoat density should be modelled to see if the sterilisation and mortality rates that are required to achieve a given level of population control are realistic targets. Also, population control should be defined in terms of accrued benefit for wildlife by establishing the relationships between stoat densities and the viability of prey populations.

Biological control of fertility or mortality may never be suitable as stand‐alone control options for stoats, particularly when some native fauna survive only if stoats are reduced to very low densities. Biological control may have greater potential when integrated with conventional control.     

Pressure pain sensitivity and hardness along human normal and sensitized muscle

The spatial distribution of pressure sensitivity and muscle hardness was examined on normal muscle tissue and muscle tissue after induction of delayed onset muscle soreness (DOMS). The pressure sensitivity and muscle hardness were assessed at nine sites on the tibialis muscle from the proximal to distal tendon on two separate days. In total 37 healthy volunteers participated in three experiments. In the first experiment pressure pain threshold (PPT) and pressure pain tolerance (PPTO) were assessed. Decreased PPT and PPTO were found on day 2, 7 days after day 1. Proximal and distal stimulation sites were harder compared to muscle belly sites. In a second experiment two different probe sizes were used. Variation in PPT between the nine sites was found for the large probe with muscle belly being less sensitive to pressure stimulation compared to proximal and distal sites. The most proximal stimulation site was harder compared to muscle belly sites. In a third experiment PPT and muscle hardness were assessed before and 48?h after eccentric exercise. PPT at two muscle belly sites was significantly decreased during DOMS. No specific sites were harder during DOMS, the average muscle hardness across sites was however significantly increased. Decreased PPT and increased muscle hardness did not correlate. In conclusion, within subjects the pressure sensitivity varies along the musculoskeletal unit. In DOMS, specific muscle belly sites were more sensitive to pressure stimulation. Muscle–tendon sites were harder compared to muscle belly sites.     

Heterotopic Renal Autotransplantation in a Porcine Model: A Step-by-Step Protocol

Kidney transplantation is the treatment of choice for patients suffering from end-stage renal disease. It offers better life expectancy and higher quality of life when compared to dialysis. Although the last few decades have seen major improvements in patient outcomes following kidney transplantation, the increasing shortage of available organs represents a severe problem worldwide. To expand the donor pool, marginal kidney grafts recovered from extended criteria donors (ECD) or donated after circulatory death (DCD) are now accepted for transplantation. To further improve the postoperative outcome of these marginal grafts, research must focus on new therapeutic approaches such as alternative preservation techniques, immunomodulation, gene transfer, and stem cell administration.Experimental studies in animal models are the final step before newly developed techniques can be translated into clinical practice. Porcine kidney transplantation is an excellent model of human transplantation and allows investigation of novel approaches. The major advantage of the porcine model is its anatomical and physiological similarity to the human body, which facilitates the rapid translation of new findings to clinical trials. This article offers a surgical step-by-step protocol for an autotransplantation model and highlights key factors to ensure experimental success. Adequate pre- and postoperative housing, attentive anesthesia, and consistent surgical techniques result in favorable postoperative outcomes. Resection of the contralateral native kidney provides the opportunity to assess post-transplant graft function. The placement of venous and urinary catheters and the use of metabolic cages allow further detailed evaluation. For long-term follow-up studies and investigation of alternative graft preservation techniques, autotransplantation models are superior to allotransplantation models, as they avoid the confounding bias posed by rejection and immunosuppressive medication.     

Classification of Chinese herbs based on the cluster analysis of delayed luminescence

Traditional Chinese material medica are an important component of the Chinese pharmacopeia. According to the traditional Chinese medicinal concept, Chinese herbal medicines are classified into different categories based on their therapeutic effects, however, the bioactive principles cannot be solely explained by chemical analysis. The aim of this study is to classify different Chinese herbs based on their therapeutic effects by using delayed luminescence (DL). The DL of 56 Chinese herbs was measured using an ultra‐sensitive luminescence detection system. The different DL parameters were used to classify Chinese herbs according to a hierarchical cluster analysis. The samples were divided into two groups based on their DL kinetic parameters. Interestingly, the DL classification results were quite consistent with classification according to the Chinese medicinal concepts of ‘cold’ and ‘heat’ properties. In this paper, we show for the first time that by using DL technology, it is possible to classify Chinese herbs according to the Chinese medicinal concept and it may even be possible to predict their therapeutic properties. Copyright © 2015 John Wiley & Sons, Ltd.     

Nondestructive evaluation of photosynthesis by delayed luminescence in Arabidopsis in Petri dishes

Nondestructive evaluation of photosynthesis is a valuable tool in the field and laboratory. Delayed luminescence (DL) can reflect charge recombination through the backflow of electrons. However, DL detection has not yet been adapted for whole plants in Petri dishes. To compensate for differences in DL decay between sibling Arabidopsis plants grown under the same conditions, we developed a time-sequential double measurement method. Using this method, we examined the influence of photosynthetic electron flow inhibitors, and differences in the DL decay curves were categorized by considering the initial and late phases of the decay curves, as well as their intermediate slopes. The appearance of concavity and convexity in DL curves in Arabidopsis was different from unicellular algae, suggesting complexity in the photosynthetic machinery of higher plants. This detection method should be invaluable for evaluating photosynthetic defects in higher plants under sterile conditions without interrupting plant culture.     

Ultrastructural Impact of Tobacco Rattle Virus on Tobacco and Pepper Ovary and Anther Tissues

The one‐third of plant viruses are seed transmitted, and this has significant economic consequences. Tobacco rattle virus (TRV), belonging to the genus Tobravirus and family Virgaviridae, has one of the widest host range of any known plant viruses. TRV infects vegetative organ and effects seed and pollen development that results in a decrease in crop yield. The mechanisms by which Tobravirus is transmissible to seeds are still poorly understood. The presence of the virus in pollen grains and inside ovaries is linked with seed transmission and can have effects on virus particles' transport during the pollination and fertilization process. This paper focuses on the significant impact of TRV on pepper and tobacco anthers and ultrastructure changes in ovaries. The presence of two types of TRV particles in ovary wall parenchyma and vascular tissues as well as in placenta cells was demonstrated via ultrastructural analysis. For the first time, the regular inclusion of virus particles was reported in both ovule integuments and nucellus parenchyma cells. Immunolocalization of TRV capsid proteins indicated the deposition of TRV CP epitope in ovary vascular bundles and in placenta cells. Moreover, the presence of virus particles was demonstrated inside pepper seeds in endothelium and integument parenchyma layers as well as on the embryo cell wall. Virus particles were found not only on the surface of pollen grains but also inside pepper pollen protoplasts in mature anthers. Also, this is the first time where TRV particles are reported in both differentiated endothecium cells and the remaining tapetum cells. Moreover, the detection of TRV capsid protein epitope in tobacco and pepper vascular anther tissues as well as in tapetum and endothecium cells was correlated with TRV distribution in infected anthers. Demonstrated analyses indicated that pollen grains and ovaries with ovules as well as could be a natural source of TRV transmission.     

毛竹的花药发育研究

竹类植物因有着较长的开花周期,其生殖生物学研究的报道相对较少。该研究采用石蜡切片与野外观察的方法,对毛竹花药的发育以及花药发育与花序的关系进行了研究。结果表明:毛竹的花药壁结构包括4层细胞:表皮细胞、药室内壁细胞、中层细胞和绒毡层细胞。药室内壁和中层都只有一层细胞,而且细胞形状较扁,花药发育后期药室内壁会逐渐降解,而中层则会完全解体消失。花药壁的发育为单子叶型,绒毡层为腺质型,而且只有一层,细胞径向较长,最后也会消失。小孢子母细胞减数分裂时,胞质分裂方式为连续型。形成的小孢子经一次有丝分裂后逐渐形成成熟花粉粒,大多为二细胞型,很少产生三细胞型。此外,还发现毛竹花药的发育与花序形态变化存在着相对应的关系。野外连续观察和切片发现,随着花序形态的不断发育变化,首先花药开始形成并不断分化,药壁备层也逐渐形成;接着小孢子逐渐成熟,备层也慢慢随之解体、消失;最后花药逐渐开裂并开始散粉。该研究结果不仅丰富了毛竹和竹类生殖生物学的研究内容,而且对毛竹种质的研究也具有重要意义。