Marisia - Maros Megyei Múzeum Évkönyve 35/2. (2015)
Botany
L. ROMAN, A. HOSU, C. VASILIU, H. ROMAN, Gh. CIUCÄ, G. MIHÄESCU the nitrogen is able to convert molecular nitrogen (N2), into ammonia (NH3) [4, 9]. B. pumilus are important agents due to the proteases they produce and which are used in the chemical, food, pharmaceutical and / or presents a serious problem in the quality assurance of these industry segments. Less frequently B. pumilus isolated was also involved in food toxicity and in human infections, including skin lesions similar those produced by the B. anthracs [2]. In 2006, there were reported three cases of infection with B. pumilus. Strain isolated produced a lipopeptide complex (pumilacidins), known to have toxic effects on human epithelial cells. Symptoms have manifested as dizziness, headache, chills, back pain, stomach cramps, diarrhea [3]. Tena (2007) reported in an article, 3 cases of patients, the same family of shepherds, with skin lesions produced by B. pumilus [13]. The treatment consisted of amoxiclav and in one case, with ciprofloxacin for long-term. Thus, B. pumilus research is of considerable interest to understand the physiological diversity, genetic correlation with other Bacillus spp. and possibly the presence of toxicity-genes. B. subtilis is an aerobic ubiquitous microorganism, but can live also in anaerobic conditions by using nitrate or nitrite as a terminal electron acceptor or by fermentation in the absence of electrons using pyruvate dehydrogenase for pyruvate metabolize [6]. Pyruvate formed in glycolysis penetrates the mitochondria (transportation) and undergoes oxidative decarboxillare to acetyl CoA (pyruvate dehydrogenase complex). Acetyl CoA is totally oxidized (NAD + and FAD) in tricarboxylic acid cycle (TCA) to form C02, NADFf, FADT12, ATP [Jelea, 2015]. B. subtilis produces a variety of proteases and other enzymes that facilitate the degradation of the natural variety of substrates. Bacillus appears in a population of 106-107 per gram of the soil. It is estimated that 60% of existing soil bacillus is dormant spore form [1]. In order to determine the mode of action of B. subtilis on the wood, numerous experiments have been made by subjecting the wood to non-sterile water or direct bacterial attack. Following the analysis of results it was found that B. subtilis acts only on sapwood, compared with Trichoderma viride which act on the heartwood. As biotechnologies B. subtilis is used to increase the permeability of wood prior to use spraywith protective role [8, 10]. The general principle in changing the chemical composition of wood is a chemical reaction with functional groups (mainly hydroxyl groups) of cell wall polymers (cellulose, hemicellulose, lignin) and covalent crosslinkage. They lead to changing the chemical and physical characteristics of wood [11]. Through introduction of consistent groups of cell walls, the cell wall growth and pore size decreases [1993]. Therefore, the moisture content decreases of the equilibrium because the available space between the cell wall polymers decreases and no longer includes water molecules. High resistance against attack of bacteria or fungi is assumed to be rather due to changes in the chemical properties of the wood structure, than a consequence of the toxic effect against them. Changes in the composition are not toxic wood degrading organisms but prevent their colonization [11]. Cellulose is the main component of the plant cell wall. Cellulases are groups of enzymes involved in conversion of cellulosic substrates by fermenting sugars. The most important are: endoglucanase (EC 3.2.1.4), exoglucanase or celobiohidrolase (EC 3.2.1.91) and ß — glucosidase (EC 3.2.1.21). Endoglucanase hydrolyze ß — 1,4 in the cellulose molecule, whereas exoglucanase cleaved the ends to release cellobiose, and ß — glucosidase and converts cellobiose to glucose. Bacillus spp , Clostridium spp., Cellulomonas spp., Thermomonospora spp, Ruminococcus spp., Bacteroides spp., Erwinia spp. and Acetivibrio spp. were identified as producing cellulases. The isolation and characterization of new enzymes that hydrolyze cellulose from bacteria, is still a very active research domain because the bacteria have a growth rate higher than the mushrooms, which leads to greater production of enzymes [Singh, 2013]. 42
