A Remote Assay for Measuring Canine Platelet Activation and the Inhibitory Effects of Antiplatelet Agents

Background

Antiplatelet medications are increasingly used in dogs. Remote analysis of platelet activity is challenging, limiting assessment of antiplatelet drug efficacy.

Hypothesis/Objectives

To evaluate a method used in humans for stimulation and remote analysis of canine platelet activity.

Animals

Forty‐five dogs of various ages without a coagulopathy or thrombocytopenia. Six were receiving antiplatelet medication.

Methods

Prospective observational study. Platelets were stimulated with combinations of arachidonic acid (AA) and epinephrine (Epi) or adenosine diphosphate (ADP) and the thromboxane A₂‐mimetic U46619 (U4). PAMFix was added to the blood samples to facilitate delayed analysis of platelet activity. Activity was assessed by flow cytometric measurement of surface P‐selectin (CD62P) expression.

Results

Canine platelets could be stimulated with both AA/Epi and ADP/U4. The levels of P‐selectin were significantly greater than paired, unstimulated samples (P < 0.001). Inhibition of P‐selectin expression occurred after this stimulation by adding antiplatelet drugs in vitro. The efficacy of antiplatelet drugs in samples from treated dogs was also measurable ex vivo using this method. Delayed analysis of platelet activity at time points up to 22 days demonstrated excellent correlation between respective mf values at each time point (r² = 0.92, P < 0.0001).

Conclusions and Clinical Importance

This study evaluated a new method to remotely assess canine platelet activity. It shows that PAMFix can be used for this purpose. This provides opportunities to interrogate the inhibitory action of antiplatelet drugs in clinical settings.     

Additive and synergistic antifungal effects of copper and phenolic extracts from grape cane and apples

Background

Organic viticulture seeks sustainable alternatives for eco-toxic copper fungicides to control downy mildew caused by Plasmopara viticola. (Poly)phenol-rich extracts of agricultural byproducts are known to possess antifungal activity, but high production costs often limit their actual implementation.

Results

We developed and produced novel ligninsulfonate-based grape cane extract (GCE) formulations and an apple extract on a pilot plant scale, including a detailed (poly)phenol characterization by high-performance liquid chromatography photodiode array mass spectrometry (HPLC-PDA-MS). Our GCE formulations alone reduced downy mildew disease severity in greenhouse trials by 29%–69% in a dose-dependent manner, whereas a standard application of the copper-based agent alone reached ~56%. When applied together, disease severity was diminished by 78%–92%, revealing a synergistic effect that depended on the mixture ratio. Combining GCE formulations with the apple extract, additive effects were found (80% disease severity reduction).

Conclusion

The studied plant extracts are proposed to both substitute for and synergistically reinforce copper fungicides in grapevine downy mildew control. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Delayed inoculation and competition of Rhizobium meliloti in annual Medicago species

Seed inoculation is frequently essential for annual Medicago establishment in Mediterranean dryland farming systems. As post-planting soil inoculation is often practiced when seed inoculation fails, the effect of delayed inoculation was investigated. Roots of Medicago rigidula (L.). All selection 716, and Medicago rotata Boiss. selection 2132, were initially pre-exposed to Rhizobium meliloti strains. Subsequently, roots were exposed to a secondary inoculum after 6, 48 and 168 h to simulate delayed inoculation. and subsequent establishment of others strains in the nodules were investigated. Combinations of highly effective and host compatible ICARDA strains (M15 and M53) and effective-ineffective strains (M15 and M28) were used to evaluate proportional nodulation responses. Plants were harvested after 6 weeks of growth. Nodules were assessed for distribution in the root system and for occupancy based on their differential resistance to kanamycin and streptomycin, and, in the case of ICARDA M28, on nodule characteristics. The strain ICARDA M15 was a better competitor than ICARDA M53 when applied in equal density in M. rotata, at zero time. While forming nodules with M. rigidula, ICARDA M53 was equally competitive under the same conditions. With ICARDA M15 as the primary inoculum, and ICARDA M53 delayed for 6, 48 and 168 h, the incidence of ICARDA M15 nodules increased on M. rigidula from 43% (at zero time) to 86, 94, and 97% and, on M. rotata, from 78% (at zero time) to 88%, 95%, and 98% for the three time delays, respectively. Pre-exposure of 2-day old M. rigidula seedlings to the ineffective strain ICARDA M28 as the primary inoculant was followed by significant nodule number increases (P 0.01) as compared with ICARDA M15. Nonetheless, when ICARDA M15 was the primary inoculum, M28 was able to produce about 35% of the nodules when applied at the 6 and 48 h time delays. However, with ICARDA M28 as the primary inoculum, followed by ICARDA M15, nodule occupancy of ICARDA M28 in M. rigidula increased from 40 (at zero time) to 75%, 80%, and 95% for the three time delays, respectively. The percentage of total nodulation by M28, applied at the three delay times, was markedly lower (10%, 5% and 1%, respectively) when M. rotata was pre-exposed to ICARDA M15. This suggested a host preference for ICARDA M15, even if applied as a late inoculum. Results indicate that the early events in the nodulation process of annual medics coupled with host-specificity factors are perhaps the most critical for competition among R. meliloti strains for nodule formation.     

早收栽培下心香甘薯延后收获的特征特性观察

为明确早收栽培情况下,心香甘薯延后收获的薯块膨大增重动态,开展了早收栽培下,心香甘薯延后收获的分期掘薯观察试验。研究结果表明,心香甘薯不但结薯早、前期薯块膨大快,而且后期薯块膨大增重比例也相当高,心香在早收栽培下延后收获,也能取得较高的产量。     

正常生长条件下推迟授粉对玉米子粒生长的影响

通过对先后吐出苞叶的花丝进行特定时间的授粉,研究正常生长条件下推迟授粉对玉米子粒生长的影响。结果表明,推迟授粉对先授粉子粒的生长影响较小,先授粉子粒粒重无显著差异,但显著减低了后授粉子粒的粒重,先玉335及登海605两个品种表现一致。进一步研究发现,后授粉子粒的生长动态即干物质积累动态与正常授粉子粒并不存在显著差异,先玉335、登海605、郑单958和大成168这4个品种表现一致,说明无胁迫条件下,推迟授粉仅仅相对推迟了后授粉子粒的生长发育时期,生长时间缩短,从而影响了子粒粒重形成。因此,正常生长条件下推迟授粉事件并未影响子粒生长,胁迫条件下的其他因素可能是造成子粒败育的根本原因。     

A molecular epidemiology study reveals the presence of identical genotypes on grapevines and ground cover weeds and the existence of separate genetic groups in a Botrytis cinerea population

Botrytis cinerea, the grey mould agent, is one of the most important pathogens of grapevine, due to the great yield losses caused and the economic costs related to disease control. Ground cover plants are assumed to have a role in the complex epidemiology of the pathogen, even if no information on the genetic variability of the strains is available. In this study, a molecular epidemiology approach, based on the comparative analysis of the nucleotide sequences of multiple genes (ITS1-ITS2, G3PDH, NEP1, NEP2, BC-hch, and sdhB), was used to evaluate whether B. cinerea isolated from herbaceous species contributes to grey mould diffusion on grapevines. From 330 samples collected in two vineyards in Lombardy, Italy, 63 B. cinerea strains were isolated from tissues of grapevine with symptoms (50 strains) and spontaneous ground cover plants (13 strains). Capsella bursa-pastoris, Cardamine impatiens, Lamium purpureum, and Crepis tectorum were identified as novel B. cinerea hosts. Sequence analysis and phylogeny showed that the same genotypes were present on both grapevines and herbaceous plants, with no fitness (estimated from growth and sporulation on potato dextrose agar) or pathogenicity (on grapevine leaves and berries, and tomato leaves) penalties. This confirms that ground cover plants can be a source of inoculum for B. cinerea on grapevine. Moreover, phylogenetic analysis of the BC-hch gene allowed the identification of two genetically distinct clusters, characterized by vegetative incompatibility and different distributions of the mating types, fitness, and pathogenicity. Therefore, B. cinerea seems to be composed of two diverging subpopulations that do not differ for host specialization.     

红蓝绿LED 延时补光对日光温室番茄育苗的影响

以番茄品种辽园多丽为试材,选择白光（W）及红光（R）、蓝光（B）、绿光（G）3 种LED 光源组成6 种不同比例组合光R9B1（9∶1,灯的数量比,下同）、R8B2、R7B3、R9G1、R8B1G1、R7B2G1,研究不同LED 光源延时补光对冬春季日光温室番茄幼苗生长的影响。结果表明：补照LED 光源不同程度地促进了番茄幼苗的生长,其中R7B2G1 的效果最为显著,与不补光对照相比,茎粗增加27.42%,全株鲜质量和干质量分别提高17.84%、30.91%,壮苗指数提高57.61%;幼苗根系活力、叶绿素含量与净光合速率、叶片可溶性糖含量等也显著提高。综上,在红蓝光源的基础上增加一定比例的绿光,能显著促进番茄幼苗生长。     

寒冷地区延迟播种期与插秧期对水稻产量及品质的影响

在吉林省气候条件下,研究了延迟播种、延期插秧对水稻产量与质量的影响。结果表明,吉林省适宜的播种期为4月12日,适宜的插秧期为5月25日,4月17～27日播种,5月30日至6月10日插秧,产量虽然下降9.57%～15.43%,但是产量能达到8 000 kg/hm2以上,与常规栽培的产量相近。5月2～17日播种,6月15～30日插秧,产量下降34.57%～88.83%,而且单穴穗数、每穗粒数、饱满千粒重、混合千粒重、饱满粒率、经济系数、生物产量、糙米率、精米率、整精米率、胶稠度等随播种期与插秧期的延后而明显下降;垩白率、垩白度明显上升。延迟播种不宜超过4月27日,延期插秧不宜超过6月10日。     

磁场胁迫对绿豆叶片延迟发光的影响(英文)

[目的]研究磁场胁迫对绿豆叶片延迟发光的影响。[方法]以绿豆叶片为试验材料,用BPCL型微弱发光测量仪测量超弱发光的变化,先测量本底和叶片的自身发光,再把叶片分别放入225和450mT磁场中处理10、20、30s后,分别测定其延迟发光曲线,连续测量3次,比较延迟发光曲线和总光子数与自身发光不同之处。每次测量时间为50s,间隔0.1s。试验在恒温17℃暗室的条件下进行,避免外界刺激温度和其他光源对试验结果的影响。[结果]叶片内部对磁场刺激的吸收有其自身的法则,一定的磁场强度和一定的处理时间能够激发绿豆叶片体内延迟发光,但超过一定的胁迫时间,就会减弱叶片体内超弱发光强度;在刺激前期随时间延长磁致发光明显,但超过一定时间限度后随时间推移磁致发光就会越来越弱。[结论]超弱发光的测定是在不影响体系内部环境、不破坏叶片组织结构情况下进行的,其规律性变化是体系内部各组成部分之间相互作用强弱的体现,是整个体系内部生理状态的整体体现,比体系内部某一部分或某一物质的变化更能反映衰老的过程。因此,超弱发光可以作为一个整体性指标,从体系内部各组成部分之间的相互作用上研究叶片的衰老过程,也可以作为一种新的生物物理方法来研究生物的生理功能作用及衰老机理。     

不同生长调节剂对新美人指葡萄延后效果的影响

以新美人指葡萄为试材,于果实发育中期(7月18日)分别用5mg/LCPPU,25mg/LGA3+5mg/LCPPU,100mg/LNAA及25mg/LGA3浸蘸果穗。在果实处理后109d采样,研究了不同处理对葡萄单果重、硬度、可溶性固形物含量及糖酸等指标的影响。结果表明,各处理均能不同程度地延迟果实成熟,与对照均有一定差异。其中以25mg/LGA3+5mg/LCPPU的延后效果最好,可溶性固形物、糖酸等指标均与对照差异性最大,其中果实处理后109d可溶性固形物含量、可溶性糖含量及可滴定酸含量分别是对照的66.76%、59.05%和173.50%,并在后期单果重、固形物及含糖量均有较大增长,接近对照。