# Basic Bioelement Contents in Anaerobic Intestinal Sulfate-Reducing Bacteria
## 3 Results  
In our previous research, SRB strains were isolated and identified to belong to the _Desulfovbironaceae_[47]. Figure 1 shows SRB strains isolated from IBD patients and healthy individuals (control). However, no significant difference in cell morphology was observed. Therefore, the content of 11 micro- and trace elements in the bacterial cells of SRB isolated from the studied patients were investigated. Figure 2 and Table 2 shows the contents of 11 elements. According to the data obtained from the content of chemical elements in the bacterial cells of SRB, isolated from patients with IBD and healthy, differences are visible for all the metals. In bacteria from the control group of SRB was noted the presence of elements such as sodium 3.58-4.61 ug g\({}^{-1}\), potassium 15.1-22.8 ug g\({}^{-1}\), calcium 4.6-22.1 ug g\({}^{-1}\), magnesium 0.61-1.21 ug g\({}^{-1}\), zinc 0-0.55 ug g\({}^{-1}\), iron 1.16-18.15 ug g\({}^{-1}\), and trace amounts of copper, manganese, cobalt, nickel, and molybdenum. Significant changes were observed in SRB cells from [PERSON]'s disease patients compared to the control group in calcium content (range of concentrations calcium: 3.0-55.6 ug g\({}^{-1}\); zinc: 0-0.88 ug g\({}^{-1}\); magnesium: 0.77-1.69 ug g\({}^{-1}\); potassium: 16.3-27.9 ug g\({}^{-1}\)). The content of the bioelements inside the SRB were increased by almost 2.5, 1.6, 1.39, and 1.2 times, respectively. Figure 1: The morphology of _Desulfovibrio_ cells from patients with IBD. Note. Strains from patient with [PERSON]'s disease: _D. vulgaris_ M1.2 (**A**), ulcerative colitis: _D. vulgaris_ M3.1 (**B**) and control (healthy): _D. vulgaris_ Z8.2 (**C**) and _D. vulgaris_ Z11.1. (**D**). Figure 2: The content of elements in the sulfate-reducing bacteria SRB isolated from patients suffering from IBD. Notes: [PERSON]’s disease (CD), ulcerative colitis (UC), healthy (H). The content of iron was 0.4-10.86 \(\mathrm{\SIUnitSymbolMicro g}^{-1}\) and decreased 1.67 times. For SRB strains isolated from patients suffering from UC, the content of iron was observed in the concentration 0.42-6.42 \(\mathrm{\SIUnitSymbolMicro g}^{-1}\), which is 2.82 times less than the healthy group. The contents of zinc, calcium, magnesium, and potassium were decreased 1.71, 1.51, 1.25, and 1.2 times, respectively. It was noted that the sodium contents in all three groups of SRB strains fluctuated slightly. Significant variations in calcium content may be due to changes in the functioning of the cytoplasmic membrane, where this element is involved. Changes in the content of copper, manganese, cobalt, nickel, and molybdenum were also noted, but insignificant. However, this does not exclude the role of these elements in the functioning of SRB cells under different conditions of IBD. To determine the influence of the elements' composition on the distribution of SRB strains, cluster analysis by the PCA method was performed. This method is widely used for the analysis of multidimensional systems in biology, physics, medicine, etc. [44; 45; 48; 49]. PCA is based on three components: scores, loadings, and explained variations. For the analysis, we used data on the content of 11 chemical elements in the cells of 35 strains of SRB isolated from patients with IBD and the control healthy persons. Characteristics of the three obtained principal components are shown in Table 3.  
The first principal component, PC1, is significant with an eigenvalue of 5.02 and explains up to 45.65% of the variations. Therefore, the main factors influencing the variations in the SRB isolated from patients with IBD are the content of the micro- and trace elements such as manganese (with power 0.87), magnesium and cobalt (0.86), calcium (0.84), molybdenum (0.81), and iron (0.78). That is, within the main component, the greatest