**3.2.2 Acrosomal membrane integrity**

Acrosome is the acidic secretory organelle filled with hydrolytic enzymes. Assessment of the acrosomal status is a very important part of semen evaluation, in the view of the role of this structure in the maintenance of spermatozoal ability to penetrate the egg's zona pellucida (in mammals), or the egg envelope (in birds) and the ability to fuse with the egg plasma membrane. Cells must retain a normal acrosome to ensure that the acrosome reaction may occur at the suitable time to facilitate fertilization (Esteves et al., 2007). Also the determination of the acrosome status in cryopreserved sperm is of the fundamental importance as cryopreservation directly damages sperm membrane, which could be followed by a loss of the acrosomal matrix contents.

Acrosomal status may be assessed using lectins, such as peanut agglutinin from *Arachis hypogaea* (PNA) or *Pisum Sativum* agglutinin (PSA), conjugated with different fluorescent probes like fluorescein isothiocyanate (FITC), phycoerythryn (PE) or Alexa Fluor®, (Graham et al., 1990; Kawakami et al., 2002; Nagy et al., 2004; Partyka et al., 2010; Peña et al., 2001; Rijsselaere et al., 2005). For human sperm concanavalin A lectins (ConA) is used as well (Holden et al., 1990). The PNA labelling is specific for the outer acrosomal membrane and it binds to β-galactose moieties. Whereas the PSA is labelling α-mannose and α-galactose moieties of the acrosomal matrix. The absence of the fluorescence on the living sperm is indicative for an intact acrosome, and fluorescence is indicative for acrosome disruption or acrosome reaction (Silva & Gadella, 2006). Since PNA agglutinin displays less non-specific binding to other areas of the spermatozoa, it leads some researchers to favour this over PSA (Graham, 2001). Lectins may be also combined with Hoechst 33258, carboxy-SNARF/PI, ethidium homodimer allowing for simultaneous assessment of acrosomal status and membrane integrity (Fig. 6b) (Kawakami et al., 1993; Szász et al., 2000).


**5.1 Salinity stress**

High salt concentrations in the soil make it difficult for roots to draw water from the ground and can be damaging to crops, with adverse effects such as ethylene production, plasmolysis, an unbalanced diet, the inhibition of photosynthesis, and the creation of reactive oxygen species (ROS) [34]. However, one of the ways by which plants manage salinity stress is via osmotic adaptation. A physiological technique employed by crops to sustain a variety of water movements between cells without experiencing turgor or growth decreases is called osmotic adaptation [35]. The buildup of appropriate solutes in plant cells, including proline and glycine betaine, serves as an illustration of this [34]. Furthermore, the existence of salt-tolerant AMF species was demonstrated by several recent scientific studies to alleviate the plant's salinity stress. The following four AMF properties are specifically mentioned by the researchers as having the capacity to reduce salt stress:

The benefits of arbuscular mycorrhiza fungi (AMF) on cassava plant growth under salinity have rarely been studied in field settings but in controlled settings. An example is a study conducted by Carretero et al. [20]. This study examined the effects of *G. intraradices* colonization on three cassava cultivars' biomass and salt tolerance

(measured as growth) (SOM-1, 05, and 50). In both AMF-inoculated and noninoculated cassava cultivars, the survival rate of the root, stem, and leaf development, as well as nutrient accumulation, were assessed in the presence of different sodium chloride concentrations (0, 68.4, or 136.8 mM) in the medium. It was reported that at 136.8 mM of salt, the AMF colonization boosted plant survival and encouraged growth. The SOM-1 cultivars outperformed the other two in terms of salt tolerance. In addition to promoting growth, the *G. intraradices*-inoculation proved essential for protecting salt-sensitive cassava cultivars (especially in salt-sensitive cultivars). When compared to non-mycorrhizal cultivars growing in the absence of salt, the AMF cultivars grew in 136.8 mM of NaCl2 and produced more dry weight. The results show that AMF-colonization offers a biological process whereby cassava cultivars can increase their salt tolerance and biomass, which, in both low- and high-stress settings, is essential for optimal cassava development [20].


**4. Conclusions**

Targets made of natNi and 60Ni were irradiated by bremsstrahlung photons with energy up to 55 MeV; the radionuclide composition and yields of nuclear reactions on natNi, 60Ni, and 58Ni were determined. It was established that in every case, the activities of produced 56,57,58Co were higher than the activity of 55Co, and therefore enough for preclinical research of radiopharmaceuticals based on cobalt. It was also demonstrated that the radionuclide purity of 55Co produced by the photonuclear method at 55 MeV is not sufficient for PET. A fast, simple, and effective method of cobalt isotopes separation without a carrier from irradiated targets by extraction chromatography was developed; it was demonstrated that the separation of Co(II) is possible in wide range of HCl concentrations (from 0.01 to 3 M). The separation factor of Ni/Co was 2.8·105 , the yield of Co(II) was close to quantitative, and separation lasted for no longer than 0.5 h.

**Author Contributions:** Conceptualization, A.G.K., A.A.K., S.E.V. and B.F.M.; methodology, A.G.K., S.S.B., V.V.K. and A.A.K.; software, S.S.B. and A.A.K.; validation, A.G.K., A.A.K., S.E.V. and B.F.M.; formal analysis, A.G.K., S.S.B. and A.A.K.; investigation, A.G.K., J.S.B., T.Y.E., S.S.B., A.A.K. and V.V.K.; resources, V.V.K., S.E.V. and B.F.M.; data curation, S.S.B.; writing—original draft preparation, A.G.K., J.S.B. and T.Y.E.; writing—review and editing, S.S.B., A.A.K., S.E.V. and B.F.M.; visualization, A.G.K., J.S.B., T.Y.E., S.S.B. and A.A.K.; supervision, B.F.M.; project administration, B.F.M.; funding acquisition, A.G.K., S.E.V. and B.F.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** The study was supported by the Russian Science Foundation (project no. 21-13-00449).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.