Photorespiratory and respiratory decarboxylations in leaves of C3 plants under different CO2 concentrations and irradiances

We used an advanced radiogasometric method to study the effects of short-term changes in CO2 concentration ([CO2]) on the rates and substrates of photorespiratory and respiratory decarboxylations under steady-state photosynthesis and in the dark. Experiments were carried out on Plantago lanceolata, Poa trivialis, Secale cereale, Triticum aestivum, Helianthus annuus and Arabidopsis thaliana plants. Rates of photorespiration and respiration measured at a low [CO2] (40 micromol mol(-1)) were equal to those at normal [CO2] (360 micromol mol(-1)). Under low [CO2], the substrates of decarboxylation reactions were derived mainly from stored photosynthates, while under normal [CO2] primary photosynthates were preferentially consumed. An increase in [CO2] from 320 to 2300 micromol mol(-1) brought about a fourfold decrease in the rate of photorespiration with a concomitant 50% increase in the rate of respiration in the light. Respiration in the dark did not depend on [CO2] up to 30 mmol mol(-1). A positive correlation was found between the rate of respiration in the dark and the rate of photosynthesis during the preceding light period. The respiratory decarboxylation of stored photosynthates was suppressed by light. The extent of light inhibition decreased with increasing [CO2]; no inhibition was detected at 30 mmol mol(-1) CO2.

Expanding the chemical space of 3(5)-functionalized 1,2,4-triazoles

An efficient approach to the gram-scale synthesis of 3(5)-substituted, 1,3- and 1,5-disubstituted 1,2,4-triazole-derived building blocks is described. The key synthetic precursors - 1,2,4-triazole-3(5)-carboxylates (20 examples, 35-89% yield) were prepared from readily available acyl hydrazides and ethyl 2-ethoxy-2-iminoacetate hydrochloride. Further transformations were performed following the convergent synthetic strategy and allowed the preparation of 1,3- and 1,5-disubstituted 1,2,4-triazole-derived esters (16 examples, 25-75% yield), 3(5)-substituted, 1,3- and 1,5-disubstituted carboxylate salts (18 examples, 78-93% yield), amides (5 examples, 82-93% yield), nitriles (5 examples, 30-85% yield), hydrazides (6 examples, 84-89% yield), and hydroxamic acids (3 examples, 73-78% yield). Considering wide applications of the 1,2,4-triazole motif in medicinal chemistry, these compounds are valuable building blocks for lead-oriented synthesis; they have also great potential for coordination chemistry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10593-022-03064-z.

Evaluation of QSAR models for predicting mutagenicity: outcome of the Second Ames/QSAR international challenge project

Quantitative structure-activity relationship (QSAR) models are powerful in silico tools for predicting the mutagenicity of unstable compounds, impurities and metabolites that are difficult to examine using the Ames test. Ideally, Ames/QSAR models for regulatory use should demonstrate high sensitivity, low false-negative rate and wide coverage of chemical space. To promote superior model development, the Division of Genetics and Mutagenesis, National Institute of Health Sciences, Japan (DGM/NIHS), conducted the Second Ames/QSAR International Challenge Project (2020-2022) as a successor to the First Project (2014-2017), with 21 teams from 11 countries participating. The DGM/NIHS provided a curated training dataset of approximately 12,000 chemicals and a trial dataset of approximately 1,600 chemicals, and each participating team predicted the Ames mutagenicity of each trial chemical using various Ames/QSAR models. The DGM/NIHS then provided the Ames test results for trial chemicals to assist in model improvement. Although overall model performance on the Second Project was not superior to that on the First, models from the eight teams participating in both projects achieved higher sensitivity than models from teams participating in only the Second Project. Thus, these evaluations have facilitated the development of QSAR models.

Synthesis of α-substituted 2-(1H-1,2,4-triazol-3-yl)acetates and 5-amino-2,4-dihydro-3H-pyrazol-3-ones via the Pinner strategy

A series of 2-(1H-1,2,4-triazol-3-yl)acetates, as well as 4-mono- and 4,4-disubstituted 5-amino-2,4-dihydro-3H-pyrazol-3-ones (including spirocyclic derivatives) have been synthesized using the Pinner reaction strategy. α-Mono- and α,α-disubstituted ethyl cyanoacetates were converted into the corresponding carboxyimidate salts that served as the key intermediates. Their further reaction with formylhydrazide or hydrazine hydrate provided triazolylacetates or aminopyrazolones (including spirocyclic derivatives), depending on the structure of the starting Pinner salt and the nature of the nucleophile. The scope and limitations of the developed synthetic method have been established.

P-050 The effectiveness of the platelet-rich plasma treatment of men with severe oligoasthenoteratozoospermia

Study question

To evaluate the effect of platelet-rich plasma (PRP) testicular injections on spermogram parameters of men with severe oligoasthenoteratozoospermia (OAT).

Summary answer

The PRP testicular injections have beneficial effects on spermatogenesis and enhance sperm concentration and motility in infertile men with OAT.

What is known already

The use of PRP therapy in assisted reproductive technologies is debatable. Despite the recent evidence of its positive effects in promoting endometrial and follicular growth, data from clinical studies are limited. There are only a few papers on the effectiveness of PRP therapy in the treatment of male infertility and sexual dysfunction. In more detail, the influence of PRP on spermatogenesis was carried out only on experimental animals. Although the mechanisms of its action have not yet been clarified, it is assumed that PRP, containing many biologically active molecules, realizes its effect through the tissue regeneration and cell proliferation.

Study design, size, duration

This prospective study included 68 men (34.6±5.2) years old with severe OAT (≤4 million/ml, motility ≤30%, normal sperm morphology ≤1%) receiving hormonal and antioxidant (AO) therapy during 6 months before in vitro fertilization cycles. 33 of them were injected once with autologous PRP (0.5 ml in each testicle). Spermogram and testosterone level were analyzed before the treatment and in 3, 4 and 6 months after it.

Participants/materials, setting, methods

Sperm concentration, motility and morphology in ejaculate of 33 men of PRP group were compared with those in the group of 35 men without PRP within 6 months of starting the treatment. Total and free testosterone level were measured in blood serum. PRP was prepared by centrifuging the patient’s own blood in the anticoagulant-containing tubes. The final concentration of platelets in the obtained sample was 950.000 – 1.250 000 cells in 1 ml.

Main results and the role of chance

4 months after the PRP injection, sperm concentration and motility increased in 18 of 33 men of the PRP group compared with the baseline (before the treatment) – 4.2 (1.0;6.9) vs 1.4 (0.1;3.4) mln/ml (p < 0.05) and 36.7 (30.6;45.8) vs 17.7 (6.7;28.2) % respectively (p < 0.05).The maximum increase in sperm motility (but not in sperm concentration!) was observed in 24 men in 6 months – 49.6 (39.6;56.4) % (p < 0.05). Percent of morphologically normal spermatozoa in ejaculate slightly increased only in 12 men in that time period from 0-1 % to 1-2%. The total testosterone level was 2.4 times higher than the baseline (31.6±7.2 vs 13.2±4.3 nmol/l, p < 0.05), the free testosterone level was 1.8 times higher (14.5±3.5 vs 7.9±3.0 pgl/ml, p < 0.05).

Unlike the PRP group, in the group of men without PRP treatment, the sperm parameters did not changed compared with the baseline in 4 months after the starting hormonal and AO treatment. A significant increase of sperin concentration was observed only in 17 of 35 patients in 6 months. Sperm motility and percent of morphologically normal spermatozoa after the treatment did not differ from the baseline. Changes in the testosterone levels were similar to changes in PRP group.

Limitations, reasons for caution

Only young and middle-aged men were considered in the study. Large randomized controlled studies are required to confirm the PRP therapy efficacy and safety of f various fertility disorders. There are also no standardized protocols for PRP preparation.

Wider implications of the findings

PRP therapy may have great potential for the treatment of male infertility and improving spermatogenesis. Optimization of methods of PRP preparation and dosage of testicular injections can enhance reproductive outcomes in assisted reproductive technologies.

Trial registration number

not applicable

P–050 The effectiveness of the platelet-rich plasma treatment of men with severe oligoasthenoteratozoospermia

Study question

To evaluate the effect of platelet-rich plasma (PRP) testicular injections on spermogram parameters of men with severe oligoasthenoteratozoospermia (OAT).

Summary answer

The PRP testicular injections have beneficial effects on spermatogenesis and enhance sperm concentration and motility in infertile men with OAT.

What is known already

The use of PRP therapy in assisted reproductive technologies is debatable. Despite the recent evidence of its positive effects in promoting endometrial and follicular growth, data from clinical studies are limited. There are only a few papers on the effectiveness of PRP therapy in the treatment of male infertility and sexual dysfunction. In more detail, the influence of PRP on spermatogenesis was carried out only on experimental animals. Although the mechanisms of its action have not yet been clarified, it is assumed that PRP, containing many biologically active molecules, realizes its effect through the tissue regeneration and cell proliferation.

Study design, size, duration

This prospective study included 68 men (34.6±5.2) years old with severe OAT (≤4 million/ml, motility ≤30%, normal sperm morphology ≤1%) receiving hormonal and antioxidant (AO) therapy during 6 months before in vitro fertilization cycles. 33 of them were injected once with autologous PRP (0.5 ml in each testicle). Spermogram and testosterone level were analyzed before the treatment and in 3, 4 and 6 months after it. Participants/materials, setting, methods: Sperm concentration, motility and morphology in ejaculate of 33 men of PRP group were compared with those in the group of 35 men without PRP within 6 months of starting the treatment. Total and free testosterone level were measured in blood serum. PRP was prepared by centrifuging the patient’s own blood in the anticoagulant-containing tubes. The final concentration of platelets in the obtained sample was 950.000 – 1.250 000 cells in 1 ml.

Main results and the role of chance

4 months after the PRP injection, sperm concentration and motility increased in 18 of 33 men of the PRP group compared with the baseline (before the treatment) – 4.2 (1.0; 6.9) vs 1.4 (0.1; 3.4) mln/ml (p < 0.05) and 36.7 (30.6; 45.8) vs 17.7 (6.7; 28.2)% respectively (p < 0.05).The maximum increase in sperm motility (but not in sperm concentration!) was observed in 24 men in 6 months – 49.6 (39.6; 56.4)% (p < 0.05). Percent of morphologically normal spermatozoa in ejaculate slightly increased only in 12 men in that time period from 0–1% to 1–2%. The total testosterone level was 2.4 times higher than the baseline (31.6±7.2 vs 13.2±4.3 nmol/l, p < 0.05), the free testosterone level was 1.8 times higher (14.5±3.5 vs 7.9±3.0 pgl/ml, p < 0.05).

Unlike the PRP group, in the group of men without PRP treatment, the sperm parameters did not changed compared with the baseline in 4 months after the starting hormonal and AO treatment. A significant increase of sperin concentration was observed only in 17 of 35 patients in 6 months. Sperm motility and percent of morphologically normal spermatozoa after the treatment did not differ from the baseline. Changes in the testosterone levels were similar to changes in PRP group.

Limitations, reasons for caution

Only young and middle-aged men were considered in the study. Large randomized controlled studies are required to confirm the PRP therapy efficacy and safety of f various fertility disorders. There are also no standardized protocols for PRP preparation.

Wider implications of the findings: PRP therapy may have great potential for the treatment of male infertility and improving spermatogenesis. Optimization of methods of PRP preparation and dosage of testicular injections can enhance reproductive outcomes in assisted reproductive technologies.

Trial registration number

Not applicable