Effect of crystalline and amorphic phenol on characteristics of peptidases and glycosidases in chironomid larvae

The effects of crystalline and amorphous phenol (0.5 mmol/L) on the characteristics of glycosidases, as well as casein-lytic and hemoglobin-lytic peptidases, which function in the whole body of chironomid larvae Chironomus sp. were studied. Crystalline phenol decreased the activity of glycosidases in comparison to the control in the temperature range 0–50 ºС, amorphous phenol – in the temperature range 0–70 ºС. The temperature optimum of glycosidases in whole body of chironomid larvae in control and experiment corresponds to 50 ºС. The activity of glycosidases in comparison to the control decreased in the pH range 5–11 (to a greater extent in the case of the lower fraction). Amorphous phenol increased the activity of casein-lytic peptidases in comparison to the control in the temperature range of 30–50 ºС, hemoglobin-lytic peptidases – in the temperature range of 0–60 ºС. The degree of the increase of enzyme activity in the temperature optimum zone of casein-lytic and hemoglobin-lytic peptidases was different: the level of enzyme activity in the experiment was higher than in the control by 2.3 and 1.8 times, respectively. The temperature optimum of the studied peptidases of chironomid larvae, regardless of the experimental conditions, corresponds to 40 °C. Crystalline phenol did not actually affect the Q10 values of glycosidases in the temperature range 0–50 °C. Amorphous phenol decreased the Q10 values at a temperature of 40–50 °C. The Q10 values of casein-lytic peptidases increased in most cases, the Q10 values of hemoglobin-lytic peptidases decreased in the presence of amorphous phenol. The process of protein hydrolysis was characterized by a break in the Arrhenius plot at 20 °C. The values of Еact in the range 0–20 °С were lower than in the zone of higher temperatures. The Еact values of the process of casein hydrolysis by peptidases of all tissues of chironomid larvae in the presence of amorphous phenol in both temperature zones increased. The Еact values of the process of hemoglobin hydrolysis by peptidases of all tissues of chironomid larvae in the presence of amorphous phenol in both temperature zones decreased. The Еact values of the process of starch hydrolysis in the presence of crystalline phenol decreased. The amorphous phenol changed the Еact values in different directions. They slightly increased in the presence of the phenol upper fraction, but they decreased in the presence of the phenol lower fraction. The data obtained indicate a significant effect of crystalline and amorphous phenol not only on activity, but also on the characteristics of peptidases and glycosidases that function in the whole body of chironomid larvae

Temperature characteristics of peptidase in chironomid larvae, potential fish prey, at various pH values

The temperature dependence of casein- and hemoglobinlytic peptidases functioning in the whole organism of chironomid larvae Chironomus plumosus, food objects of adult benthophages and juvenile fish of various ecological groups, was studied within the temperature range of 0–70 ºС at different рН values (3.0, 5.0 and 7.4). The method of mixed samples was used to determine the activity and characteristics of enzymes. Homogenates of previously crushed and carefully mixed dozens of larvae were used as enzymatically active preparations. Activity of peptidases was assayed by the increase in tyrosine concentration using the Folin-Ciocalteu reagent. It is shown that the activity of peptidases that function in the tissues of chironomid larvae depends to a considerable extent on temperature and рН, but the pH has a smaller effect on the activity and the temperature dependence of casein- and hemoglobin-lytic peptidases than temperature. The temperature optimum of the studied peptidases of chironomid larvae corresponds to 40 ºС. The Q10 values in the zone of vital temperatures are slightly changed. They are, as a rule, increased in the zone of 30–40 ºС, and are sharply decreased in the zone of high temperatures. The values of activation energy of the process of hydrolysis of casein and hemoglobin in the zone of low and high temperatures are different. The Еact values of the process of hydrolysis of casein and hemoglobin at a temperature not exceeding 20 ºС are usually below those in the zone of higher temperatures (except for hemoglobin-lytic peptidases at pH 5.0). The data obtained indicate a significant effect of pH not only on the activity, but also on the temperature characteristics of peptidases that function in the body of chironomid larvae. Differences in the characteristics of casein- and hemoglobin-lytic peptidases in chironomid larvae at different temperatures and pH can influence the digestion in benthophages and fry of all fish species

A comparative assessment of cancer-related mortality among workers employed at the various stages of pyrometallurgical production of copper

Th e authors present comparative evaluation of infl uence caused by complex of carcinogenic work conditions of main stages of copper pyrometallic production on cancer-related mortality of the workers. Findings are that raw copper enrichment, blister copper recovery through reverberative furnace melting and fi re refi ning of blister copper are carcinogenic danger for the workers. Malignancies frequency in the workers appeared to directly depend on occupational exposure to arsenic. Th e results of the workers’ cancer-related mortality correspond to data of carcinogenic risks evaluation at all stages of metallurgic production of copper. Given the study results, reasonable suggestion is to include raw copper enrichment into offi cial list of occupational processes with carcinogenic dangerДана сравнительная оценка степени влияния комплекса канцерогеноопасных условий труда основных этапов пирометаллургического производства меди на показатели смертности рабочих от злокачественных новообразований (ЗН). Установлено, что обогащение медьсодержаще го сырья, получение черновой меди способом отражательной плавки и огневое рафинирование меди представляют канцерогенную опасность для работающих. Выявлена прямая зависимость частоты ЗН у рабочих от профессиональной экспозиции к мышьяку. Результаты изучения смертности работающих от ЗН согласуются с данными оценки канцерогенных рисков (КР) на всех этапах металлургического производства меди. Исходя из результатов исследования, представляется обоснованным включение обогащения медьсодержащих руд в официальный перечень канцерогеноопасных производственных процессо

Diagnostic Possibilities of Optical Coherent Tomography of the Retina during Compression in the Chiasm-Sellar Region

Recovery and preservation of visual functions during compression in the chiasm-sellar region is possible in the case of early diagnosis of pathology and timely surgical decompression. Today optical coherence tomography (OCT) of the retina is one of the most informative methods for diagnosing pathology of the retina and optic nerve. It can, due to the presence of early diagnostic criteria, promptly detect the compression in the chiasm-sellar region and expand the indications for surgical treatment. The literature review presents the results of optical coherent tomography (OCT) of the retina during compression in the chiasm-sellar region. An analysis of literature data revealed that in patients with chiasmatic compression, the thickness of the nerve fiber layer in the peripapillary and macular areas decreases, the thickness of the macular complex, consisting of the retinal ganglion cell layer and the inner plexiform layer, decreases. Also, there is a change in the value of asymmetry between the GCC thickness indices in the nasal and temporal halves of the macular region. It has been established that a decrease in the thickness index of a macular complex may precede changes in the visual field. According to the results of single studies, a correlation was found between the parameters of the peripapillary RNFL thickness and the the internal capillary retinal plexus density in the same areas. The results of literature sources’s analysis are summarized in the table by the parameters studied, the OCT model; etiology, treating methods and the results of the OCT study. Despite the results obtained, the early specific and sensitive OCT diagnostic criteria for chiasmatic compression have not yet been developed. In addition, a change in the thickness of GCC and RNFL can also be observed in the absence of chiasmatic compression in certain types of tumors and in the presence of comorbidities (arterial hypertension). In this regard, it is necessary to conduct further studies that will reveal the informative OСT-diagnostic criteria for compression in the chiasm-sellar region, develop diagnostic algorithms taking into account the type of tumor, the presence of concomitant pathology. Early diagnostic criteria for chiasmatic compression will expand the indications and improve the result of surgical treatment of patients