An aniline-substituted bile salt analog protects both mice and hamsters from multiple Clostridioides difficile strains

Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea. The emergence of hypervirulent C. difficile strains has led to increases in both hospital- and community-acquired CDI. Furthermore, CDI relapse from hypervirulent strains can reach up to 25%. Thus, standard treatments are rendered less effective, making new methods of prevention and treatment more critical. Previously, the bile salt analog CamSA was shown to inhibit spore germination in vitro and protect mice and hamsters from C. difficile strain 630. Here, we show that CamSA was less active at preventing spore germination of other C. difficile ribotypes, including the hypervirulent strain R20291. Strain-specific in vitro germination activity of CamSA correlated with its ability to prevent CDI in mice. Additional bile salt analogs were screened for in vitro germination inhibition activity against strain R20291, and the most active compounds were tested against other strains. An aniline-substituted bile salt analog, (CaPA), was found to be a better anti-germinant than CamSA against eight different C. difficile strains. In addition, CaPA was capable of reducing, delaying, or preventing murine CDI signs in all strains tested. CaPA-treated mice showed no obvious toxicity and showed minor effects on their gut microbiome. CaPA’s efficacy was further confirmed by its ability to prevent CDI in hamsters infected with strain 630. These data suggest that C. difficile spores respond to germination inhibitors in a strain-dependent manner. However, careful screening can identify anti-germinants with broad CDI prophylaxis activity.

Efficiency of germination inhibitors appliance by storage of potato varieties for various target uses

Цель работы – определение эффективности применения ингибиторов прорастания при хранении сортов картофеля различного использования: столовых, для потребления в свежем виде, специально предназначенных для переработки на картофелепродукты, а также в качестве семенного материала. Исследования проведены в 2005–2007 и 2015–2020 годах с использованием регуляторов роста на основе д. в. хлорпрофам (Спраут-стоп; Харвест-Макс, Р; Спад-Ник, Р) и фитогормона этилена. Картофель хранили в холодильных камерах ФГБНУ «ФИЦ картофеля имени А.Г. Лорха» при температурах 3–4, 5–7, 8–10 °C. Производственные опыты по хранению проведены в АО «Озеры» Озерского района Московской области (при температурных режимах 3–4 и 8–10 °C) и ООО «ПокровскАгро» Энгельсского района Саратовской области (5–7 °C). Газацию этиленом проводили по адаптированной к российским условиям технологии Restrain. Опыты закладывали в условиях дерново-подзолистой почвы экспериментальной базы «Коренево» (Московская область, городской округ Люберцы) на фоне минерального питания N60P60K120 при локальном внесении удобрений во время нарезки гребней. Исследованиями установлено, что обработка клубней сортов столового картофеля при температуре хранения 5–7 °C препаратом Спраут-стоп способствовала снижению общих потерь на 1,0–2,0%, а при температуре хранения 8–10 °C – на 4,0–6,0%. Причем наиболее эффективно обрабатывать клубни столовых сортов в марте, а сортов картофеля на переработку – в сентябре. Применение регулятора роста Спраут-стоп на семенном картофеле оказалось неэффективным независимо от дозы и срока обработки. Использование препарата Харвест-Макс, Р на столовом картофеле сорта Гала обеспечило снижение потерь при хранении на 5,1 и 7,0% при суммарных дозах препарата 39 и 57 г/т. Применение препарата Спад-Ник, Р как отдельно, так и в сочетании с фитогормоном этиленом способствовало снижению потерь сортов картофеля, предназначенного для переработки на хрустящий картофель, на 6,9–7,7%. При этом не выявлено существенного снижения биохимических показателей клубней и пригодности картофеля к переработке при использовании ингибиторов прорастания на основе д. в. хлорпрофам. Газация семенного материала картофеля фитогормоном этиленом способствовала прибавке общей урожайности по сортам Леди Клэр и Сатурна на 14,2 и 7,4% соответственно. The aim of this research is to determine the efficiency of germination inhibitors appliance by storage of potato varieties for various target uses: table, for fresh consumption, special for processing into potato products and also as seed material. Studies were conducted in 2005–2007 and 2015–2020 using growth regulators based on active ingredient chlorpropham (Sprout-stop; Harvest-Max; Spud-nic) and the phytohormone ethylene. Potatoes were stored in the cooling chambers of the Russian Potato Research Centre at temperatures of 3–4, 5–7, 8–10 °C. Production experiments were carried out in the JSC “Ozery” of the Ozyorsky district of the Moscow region (at store temperatures of 3–4 and 8–10 °C) and LLC “PokrovskAgro” of the Engels district of the Saratov region (5–7 °C). Treatment with ethylene was carried out using the Restrain technology adapted to Russian conditions. The experiments were conducted in the conditions of sod-podzolic soil of the experimental base “Korenevo” (Moscow region, Lyuberetsky city district) with the doses of mineral fertilizers of N60P60K120 by their local appliance during cutting of ridges. In research was found that treatment of tubers of table potato varieties at a storage temperature of 5–7 °C with inhibitor Sprout-stop contributed to a reduction in total losses by 1.0–2.0% and at a storage temperature of 8–10 °C – by 4.0–6.0%. Moreover, it is most effective to treat the tubers of table varieties in March, and potato varieties for processing – in September. The use of the sprout-stop growth regulator on seed potatoes was ineffective regardless of the dose and treatment term. The use of inhibitor Harvest-Max on table potatoes of Gala variety provided a reduction in storage losses by 5.1 and 7.0% at total doses of the preparation 39 and 57 g/t. The use of inhibitor Spud-nic both separately and in combination with the plant hormone ethylene contributed to the reduction of losses of potato varieties for processing into crisps 6.9 to 7.7%. At the same time no significant decrease in biochemical parameters of tubers and in suitability of potatoes for processing when using germination inhibitors based on active ingredient chlorpropham was detected. The treatment of potato seed material with phytohormone ethylene provided an increase in total yield of the Lady Claire and Saturna varieties by 14.2 and 7.4%, respectively.

Morphobiometry and Ecophysiology of Caryocar coriaceum Wittm. (Pequi) in Cerrado Areas of Northeast Brazil

Many studies have reported that native plant species can contribute to ensuring food security in the world. Among the Brazilian species, the Caryocar coriaceum has a high utility value for the communities in Northeast Brazil but it is under threat due to the degradation of the Cerrado savannah. One way to mitigate threats is to produce large-scale seedlings. Thus, it was attempted to evaluate methods to overcome dormancy of C. coriaceum to increase and standardize germination and to analyze its morphobiometric characteristics. The fruits were weighed, measured and subjected to the selected treatments. Tests were performed to overcome dormancy The fruits were planted at a depth of 5 cm. The results showed that the fruits of C. coriaceum presented asymmetric frequency distribution with high variability for the characteristic of weight. However, a marked variation of the literature data was found. About the germination treatments tested in the laboratory, none was effective in overcoming dormancy, which may be due to the presence of inhibitory substances. Concerning seed planting, a germination index of 35% was recorded after 12 months. The conclusions suggest that there is a high phenotypic variability of the genus in the cerrado and probably the presence of germination inhibitors in seeds of this species, which should be addressed to ensure germination.

Seed Germination Inhibitors: Molecular and Phytochemical Aspects

Two major stages of seed development are dormancy and germination which finally promotes the growth of a plant. Some internal and external factors such as hormonal, genetic, chromatin development and environmental factors which maintain the seed dormancy with passing time and other suitable factors, these dormancy promoters are gradually decreased causing release of dormancy and promoting germination by the mechanisms of ROS in plant signalling, cell elongation and reverse mobilization. But dormancy has some benefits in protecting the seed from extreme condition even after natural disaster as well as serving as food for predators in order to maintain balance of nature. So, dormancy can be inhibited by some phytochemical components like terpenoids, polyphenoliic compounds, flavonoids, alkaloids and glycosides by the mechanism of inhibiting water uptake system III and II, surface sterilization, reverse mobilization, cell elongation etc

Does seed coat structure modulate gut-passage effects on seed germination? Examples from Miconieae DC. (Melastomataceae)

Fruits of Melastomataceae constitute a key resource for Neotropical frugivores. However, the mechanisms determining gut-passage effects on seed germination are poorly known. Here, we determine how bird gut-passage affects seed germination in three species of Miconieae by running germination experiments, examining changes in seed coat structure and determining germination inhibition by fruit extracts. Mature fruits of Clidemia urceolata, Leandra aurea and Miconia rubiginosa were sampled in south-eastern Brazil and seeds were submitted to treatments evaluating gut-passage effects and different concentrations of fruit extracts. Light and scanning electron microscopy were used to compare seed coat structure and thickness of control and gut-passed seeds. We found minor effects of gut passage on seed germination. However, changes in seed coat structure of gut-passed seeds of L. aurea may have been related to a decrease in germination. Our data also support the idea that germination inhibitors in fruit pulp may contribute to the inhibition effect. Our study corroborates the idea that changes in the seed coat following gut passage modulate the complex fruit–frugivore interactions, especially between plants and generalist dispersers, and that seed cleaning is a key factor determining seedling establishment in Neotropical Melastomataceae.