The Combined Effect of Shungite and Heavy Metals on the Growth of Microalgae Роpulation

The combined effect of 3 mg/L potassium dichromate, 1.5 mg/L cadmium sulfate, and 100 g/L shungite on the growth of chlorococcales green microalgae culture Scenedesmus quadricauda (Turp.) Bréb. is studied. The toxic effect of potassium dichromate and cadmium sulfate on S. quadricauda is estimated by calculating the share of living and dead cells and physiological parameters. The toxic effect of heavy metals does not manifest itself under the combined action of potassium dichromate or cadmium sulfate and shungite on S. quadricauda. The best growth of the algae culture occurred only when only shungite was added to the culture medium. Shungite can be used to neutralize the toxic effect of heavy metals.     

Effect of Plants Synthesizing Biologically Active Substances—Precocenes—on Insects

Integrated data on the direct and indirect influence of plants synthesizing biologically active substances—precocenes—on phytophagous insects developing and feeding on these plants are presented. The experimental data on individual organs and tissues as well as organ systems in various insect groups are discussed.     

Effect of Chelate-Assisted Hexavalent Chromium on Physiological Changes,Biochemical Alterations,and Chromium Bioavailability in Crop Plants—An In Vitro Phytoremediation Approach

This study revealed heavy metal–induced physiological and biochemical alterations in crop seedlings by supplementing chelating agents in the nutrient solution. Hexavalent chromium (Cr⁺⁶) induces several toxic effects in hydroponically grown rice, wheat, and green gram seedlings. A noticeable decrease was observed in root length, shoot length, biomass content, and chlorophyll biosynthesis of the seedlings grown in the nutrient solutions supplemented with Cr⁺⁶ at 100 μM. The seedling growth was stimulated with supplement of chelating agents such as EDTA, DTPA, and EDDHA. An increase in proline content was noticed with the application of Cr⁺⁶ (100 μM) in nutrient solutions. Stimulated activities of antioxidant enzymes such as catalase and peroxidase were noticed with increasing concentrations of chromium. Cr bioaccumulation was significantly high in roots of seedlings treated with Cr⁺⁶ at 100 μM in nutrient solution. Shoot translocation of Cr as depicted by transportation index (Ti) values for different crops were enhanced with the application of chelating agents. The total accumulation rate (TAR) for Cr was enhanced with the supplementation of DTPA in rice and wheat, whereas the application of EDDHA was found effective for increasing the accumulation rate of Cr in green gram seedlings. This study demonstates the role of chelating agents in lessening the toxic effects of Cr⁺⁶. The chelating agents supplemented with Cr⁺⁶ in the culture medium enhanced the Cr bioavailability in plants.     

Progress of Study on Chitosan in Regulating Plants’Growth and Eliciting Plants’Defense Responses

Important effect of chitosan on regulating plant growth , eliciting plant resistance to disease and it’s possible operating mechanism are reviewed . Chitosan shows evidence physiological effect on the key enzymes of ammonia assimilation and enhances the amination capacity in plant, which is in favor of biology synthesize and accumulation of protein . Thus , chitosan improves nutrition quality and horticulture properties of plant . Moreover , chitosan rapidly stimulates plant defense responses , then startups defensive system and elevates resistance to disease . To a further understanding of the mechanism of chitosan on plant , we have isolated and determined some biochemical properties of a chitosan-bingding protein .     

The Specificity of Controlled Protein Disorder in the Photoprotection of?Plants

Light-harvesting pigment-protein complexes of photosystem II of plants have a dual function: they efficiently use absorbed energy for photosynthesis at limiting sunlight intensity and dissipate the excess energy at saturating intensity for photoprotection. Recent single-molecule spectroscopy studies on the trimeric LHCII complex showed that environmental control of the intrinsic protein disorder could in principle explain the switch between their light-harvesting and photoprotective conformations in vivo. However, the validity of this proposal depends strongly on the specificity of the protein dynamics. Here, a similar study has been performed on the minor monomeric antenna complexes of photosystem II (CP29, CP26, and CP24). Despite their high structural homology, similar pigment content and organization compared to LHCII trimers, the environmental response of these proteins was found to be rather distinct. A much larger proportion of the minor antenna complexes were present in permanently weakly fluorescent states under most conditions used; however, unlike LHCII trimers the distribution of the single-molecule population between the strongly and weakly fluorescent states showed no significant sensitivity to low pH, zeaxanthin, or low detergent conditions. The results support a unique role for LHCII trimers in the regulation of light harvesting by controlled fluorescence blinking and suggest that any contribution of the minor antenna complexes to photoprotection would probably involve a distinct mechanism.     

Effect of γ Irradiation on the Fatty Acid Composition of Soybean and Soybean Oil

Food irradiation is a form of food processing to extend the shelf life and reduce spoilage of food. We examined the effects of γ radiation on the fatty acid composition, lipid peroxidation level, and antioxidative activity of soybean and soybean oil which both contain a large amount of unsaturated fatty acids. Irradiation at 10 to 80 kGy under aerobic conditions did not markedly change the fatty acid composition of soybean. While 10-kGy irradiation did not markedly affect the fatty acid composition of soybean oil under either aerobic or anaerobic conditions, 40-kGy irradiation considerably altered the fatty acid composition of soybean oil under aerobic conditions, but not under anaerobic conditions. Moreover, 40-kGy irradiation produced a significant amount of trans fatty acids under aerobic conditions, but not under anaerobic conditions. Irradiating soybean oil induced lipid peroxidation and reduced the radical scavenging activity under aerobic conditions, but had no effect under anaerobic conditions. These results indicate that the fatty acid composition of soybean was not markedly affected by radiation at 10 kGy, and that anaerobic conditions reduced the degradation of soybean oil that occurred with high doses of γ radiation.     

Effect of the Form of Mineral Nitrogen on the Growth and Heterotrophic Fixation of 14С-Bicarbonate in Chlamydomonas reinhardtii

Russian Journal of Plant Physiology - The earlier-detected effect of the mineral nitrogen form in the nutrient medium (ammonium or nitrate) on the quantity of ribosomes in the cells of...     

The Expression of Nerve Growth Factor Receptor on Schwann Cells and the Effect of These Cells on Regeneration of Axons in Traumatically Injured Human Spinal Cord

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The Inclusion and Selection of Medicinal Plants in Traditional Pharmacopoeias—Evidence in Support of the Diversification Hypothesis

The Inclusion and Selection of Medicinal Plants in Traditional Pharmacopoeias—Evidence in Support of the Diversification Hypothesis. An ethnobotanical study with phytochemical analyses was undertaken to examine the medicinal plants used by residents of a small rural community in northeastern Brazil. The present work tested two ideas that attempt to explain the inclusion and selection of medicinal plants in a given culture: the diversification hypothesis and the concept of versatility. The study involved 101 people and used semistructured interviews. A total of 61 plants were selected, including 25 exotic and 36 native species. Plants were classified according to their habit and analyzed for their phytochemical components. In addition, the relative importance (RI) of these plants was calculated, and a chemical diversity index (CDI) was created and applied to each of the species. Exotic and native plants were found to have significantly different occurrences of certain classes of compounds; this result supports the diversification hypothesis. It was therefore concluded that exotic plants are included in traditional pharmacopoeias to fill therapeutic vacancies that native plants cannot satisfy.     

Acromegaly—The Effects of Various Steroid Hormones on the Insulin-Induced Growth Hormone Response

The availability of a sensitive assay for human growth hormone has made it possible to directly measure the effects of various agents purported to alter growth patterns. Acromegalic patients present a special problem both in early diagnosis and in therapy. Being able to measure growth hormone in these patients provides an accurate index of activity and a precise measure of therapeutic effectiveness.In an attempt to determine whether a pituitary block of growth hormone secretion is feasible in this condition, a study was made of the effects of estrogen, androgen and glucocorticoid administration on growth hormone response to a standard insulin tolerance test in a patient with active acromegaly. In the dosage schedules used in this study, it was not possible to suppress either basal growth hormone secretion or blunt its responsiveness to the normal physiologic stimulus of hypoglycemia.     

The Effect of Short-Term Feeding of a High-Coconut Oil or High-Fat Diet on Neuroinflammation and the Performance of an Object–Place Task in Rats

The consumption of high-fat and high-sugar diets, in the form of junk food, and binge eating are now common. Increasing evidence suggests that a high-fat diet (HFD) can induce neuroinflammation and alter behavior. I aimed to study the effects of diets of differing fat content on neuroinflammation and spatial memory using an object–place (OP) task. Thirty-two adult male rats were allocated to four groups and fed a regular diet (Regular diet), a control diet (Control diet), an HFD (60% of calories from lard), or a high-coconut oil diet (HCOD; 60% of calories from coconut oil) for 3 days. Their water intake, food consumption, body mass, and metabolic variables were measured. HFD-fed rats showed significantly poorer performance on the OP task, as assessed using the discrimination index (??0.208?±?0.094), than the Regular (0.462?±?0.078; P?<?0.0001) and Control (0.379?±?0.081; P?=?0.0003) groups. However, no significant difference was observed in spatial memory between the HCOD and Regular groups. The concentrations of neuroinflammatory markers (interleukin [IL]-1β, IL-6, tumor necrosis factor α, and nuclear factor κB) were also measured in the hippocampus and prefrontal cortex. HFD-fed rats showed significantly higher levels of neuroinflammatory markers than the Regular and Control diet-fed groups. HCOD feeding did not induce neuroinflammation in the hippocampus and prefrontal cortex compared with the Regular and Control groups.

     

Does ABA in the Xylem Control the Rate of Leaf Growth in Soil-Dried Maize and Sunflower Plants?

Maize (Zea mays L.) and sunflower (Helianthus annuus L.) plantswere grown in large volumes of soil and leaf growth rate wasmonitored on a daily basis. Half the plants were given a soildrying treatment and when they showed a significant restrictionof growth rate (compared to both their daily growth rate beforedrying and the average growth rate of well-watered plants onthe same day), leaf water relations were measured and xylemsap was extracted using several techniques. There was a significant negative log-linear relationship betweenthe rate of leaf growth and the concentration of ABA in thexylem for both species. There was no clear relationship betweenleaf growth rate and leaf water potential or turgor for eitherspecies. Assessment of different methods for sampling xylemsap suggests that exudates collected from stem stumps or samplescollected by pressurizing the whole root system are suitablefor estimating ABA concentration in xylem, at least with largeplants of maize or sunflower, provided the first few hundredcubic millimetres of collected sap are used for the assay. Centrifugationof sections of stems resulted in dilution of ABA in the xylemsap with sap squeezed from parenchyma tissue. This is because,at least in plants subjected to mild soil drying, the concentrationof the ABA in the xylem is far higher than that in the cellsap of stem tissue. Results support the proposal that ABA plays a major role asa chemical signal involved in the root-to-shoot communicationof the effects of soil drying. The non-hydraulic restrictionof leaf growth by a chemical signal can be explained by theextra root-sourced ABA in the xylem and may be an importantcomponent of the modification of growth and development whichresults from prolonged soil drought. Key words: Soil drying, ABA, leaf growth, Zea mays L., Helianthus annuus L.     

Inhibitory Effects of Cycasin on Germination,Growth and α-Amylase Biosynthesis in Rice Plants

Cycasin, the toxic glycoside of cycad plants, interfered with seed germination and seedling growth of Gramineae, Crucifereae and Leguminosae. The shoots and roots of seedlings showed wilting, chlorosis and necrosis. Rice plants were most sensitive and soybean plants rather tolerant.

Respiration and α-amylase activity were markedly low in the rice seedlings treated with cycasin. Both cycasin and its aglycone, methylazoxymethanol, did not inhibit the activity of α-amylase, but did suppress the formation of α-amylase in rice endosperms. Exogenous gibberellin considerably reversed the inhibition of germination and growth, and the suppression of α-amylase formation caused by these toxins.     

The Effect of Dietary β-Sitosterol and β-Sitostanol on the Metabolism of Cholesterol in Rats

Effects of dietary β-sitosterol (S) and β-sitostanol (HS) on the metabolism and fate of labeled cholesterol intravenously injected were compared in rats fed diets high in cholesterol. Kinetic behavior of the decay curve for serum cholesterol in the HS supplemented (C + HS) group approximated to that in the cholesterol-free (control) group. The largest dilution of the label was observed in rats of the cholesterol (C) group and the least in the C + HS group, the C + S group being intermediate. The specific activity of hepatic cholesterol was in the decreasing order of the C + HS, C + S and C groups, while the situation was reversed when expressed in terms of net incorporation. Thus, cholesterol pool seemed to be much smaller in the C + HS group than in the C + S group.

In a long term feeding experiment with diets free of cholesterol, HS exhibited significantly greater hypocholesterolemic activity than S did.

These data, together with those reported previously, indicated that inhibitory effect on the absorption of both endogenous and exogenous cholesterol was much more greater in HS than in S.     

Critical Evaluation of the Volumetric “Bottle Effect” on Microbial Batch Growth

We have analyzed the impact of surface-to-volume ratio on final bacterial concentrations after batch growth. We examined six bottle sizes (20 to 1,000 ml) using three independent enumeration methods to quantify growth. We found no evidence of a so-called volumetric bottle effect, thus contradicting numerous previous reports.Microbial batch growth during confined incubation in bottles of various sizes is used daily in a broad variety of microbiological studies and methods, including bioassays such as the assimilable organic carbon (AOC) assay (6, 10, 18) and the analysis of pure culture or microbial community growth in freshwater (3, 11, 19, 20). In this context, “bottle effect” or “volume effect” is a term that has cropped up frequently in aquatic microbiology papers (e.g., references 12, 13, and 21) during the last 100 years to explain inexplicable phenomena and variations in results obtained from such batch growth studies. The uncertainty surrounding this apparent effect was clearly summarized in a recent paper by Pernthaler and Amann (16): “Such investigations are often plagued by the mysterious ‘bottle effect’, a hard-to-define concept that reflects the worry of whether phenomena observed in confined assemblages are nonspecific consequences of the confinement rather than a result of the planned manipulation.” The “bottle effect” alludes to an apparent reaction of bacteria to batchwise incubation in a confined environment, and this concept has intermittently been linked to influences on final cell concentrations (3) and grazing/bacterivory (13), a change in viability/activity parameters (9), a change in cultivability (5), and a change in population composition (1).The fact that microbiological processes during confined incubation differ from those in the environment is indisputable. However, a particular section of “bottle effect” literature focuses specifically on a volumetric “bottle effect”, where the above-mentioned effects are linked specifically to the size (or surface-to-volume ratio) of the incubation vessel (3, 8, 11-13, 15, 21). One of the oldest and best-known studies summarized clearly: “It will be observed that the densest bacterial populations appear in the bottles of water which offer the largest area of glass surface per unit volume of water” (21). This idea has established itself as dogma during the last century, with only a few differing opinions (4). However, precious little empirical data that actually quantify and explain the volumetric “bottle effect” are ever presented. In one example, Bischofberger et al. (3) observed that incubation of groundwater led to significantly more growth (about 2 log units) in small bottles (100 ml) than in big ones (10 liters). More often, however, the “bottle effect” is merely mentioned, as if it is self-explanatory and indisputable (2, 11, 12). In the present study, we took a simple but detailed look at the effect of bottle size on the outcome of short-term (<5-day) batch growth assays and compared the data critically to information in the literature and current opinion on this topic.Three batch growth experiments were conducted to assess the volumetric bottle effect on final cell concentrations after growth into stationary phase. Six different bottle sizes were used, covering the ranges most often reported in “bottle effect” literature. All glassware and Teflon-coated caps were cleaned comprehensively as described elsewhere (6) to remove any traces of organic carbon that might have been present on surfaces. The bottle sizes were as follows (water volumes and surface area-to-volume ratios [square centimeters to milliliters] are respectively included in parentheses): 1,000 ml (900 ml, 0.3:1), 500 ml (400 ml, 0.4:1), 250 ml (200 ml, 0.6:1), 100 ml (90 ml, 0.8:1), 40 ml (35 ml, 1.5:1), and 20 ml (15 ml, 2.4:1). In the first experiment, a sample of natural river water (dissolved organic carbon [DOC], 3.8 mg/liter; AOC, 0.3 mg/liter) from a small oligotrophic stream was obtained, filter sterilized with a 50-kDa dialysis filter (Fresenius Medical Care), and inoculated (at 10³ cells/ml) with a microbial community used for AOC assays (19). In the second experiment, a sample of the effluent (DOC, 1.2 mg/liter; AOC, 0.03 mg/liter; total cell concentration [TCC], 3 × 10⁵ cells/ml) from a granulated active carbon filter situated in a drinking water pilot plant (7) was collected and used directly for the experiment without additional treatment or inoculation. For the third experiment, sterile Luria-Bertani (LB) medium (diluted 1:10,000; DOC, 0.7 mg/liter; AOC, 0.46 mg/liter) was inoculated with Vibrio cholerae O1 (10³ cells/ml) as described previously (19). The water from each experiment was distributed into triplicate flasks of each size and incubated (at 30°C) until stationary phase was reached. Stationary phase was indicated by no significant increase in the TCC (measured after 3, 4, and 5 days) on consecutive days. Samples from all experiments were analyzed (i) for TCCs after being stained with SYBR green I and subjected to flow cytometry (7, 19), (ii) for ATP by using a commercial luciferin-luciferase assay (Promega Corporation) (7), and (iii) for heterotrophic plate counts (HPC) on R2A agar by a pour plate method with incubation at 30°C for 10 days. Possible biofilm growth was checked by applying sonication to selected samples. However, no wall growth in bottles of any size was observed.Growth was observed in all three experiments. The results show the net growth after subtraction of the initial cell/ATP/HPC concentrations from the final concentrations (Fig. ​(Fig.1).1). The proposed concept of the volumetric bottle effect implies that more growth should occur in smaller bottles. All data sets were subjected to regression analysis, and we observed no significant correlation (P < 0.01) between bottle size and final growth in any of the experiments by any of the three independent methods used for quantification. Figure ​Figure1A1A shows the batch growth results for a natural microbial community in prefiltered river water. This experimental setup is reflective of a typical AOC assay (6) or batch cultivation of natural microbial communities (20). Figure ​Figure1B1B shows the results for direct incubation of a treated drinking water sample. This sample and experimental setup were chosen specifically to assess any potential volumetric “bottle effect” on an indigenous microbial community in a biologically stable water sample, where only limited growth is expected. Indeed, the final cell concentration in the sample was only about 25% higher than the original cell concentration. The cultivability (HPC/TCC × 100) at day 0 was 0.4%, and at the end of the experimental period it had increased to 2.5%. This points to increased cultivability as a result of growth during confinement (5), yet it does not relate at all to the size of the incubation vessel. Figure ​Figure1C1C shows the data for V. cholerae grown in sterile LB medium (diluted 1:10,000) to stationary phase. Again, this particular setup is of specific relevance since a recently published paper on the growth of V. cholerae referred directly to the volumetric “bottle effect” to explain rather large differences between growth results from two separate studies (11, 19). The data from Fig. ​Fig.1C1C suggest at least that a “bottle effect” should be ruled out as an interfering factor in this case.Open in a separate windowFIG. 1.Effects of bottle size on bacterial batch growth of a natural microbial community in filter-sterilized surface water (A), growth of bacteria during direct incubation of water from a drinking water treatment plant (B), and batch growth of a V. cholerae pure culture in diluted LB medium (C). Growth (expressed as the net growth) was quantified by flow cytometric total cell counting (circles), total ATP analysis (diamonds), and conventional plating (squares). All data points represent averages of triplicate measurements.The results presented in this study clearly dispute the concept of a volumetric “bottle effect” on the outcome of short-term batch growth assays, be it for pure cultures or natural microbial communities. These findings contradict evidence reported by many other researchers (3, 8, 11-13, 15, 21). Although the volumetric “bottle effect” is often cited as a somewhat mysterious occurrence, it is imperative that clear experimental data are required for the critical appraisal thereof. The main experimental theory behind the phenomenon is that organic carbon adsorbs to clean glass surfaces, thus locally concentrating the carbon and creating more favorable growth conditions (2, 14). This adsorption and the fact that bacteria can utilize such adsorbed carbon have been demonstrated experimentally (14). What has, in our opinion, not been shown conclusively is that these effects can be so dramatic that they would alter the growth of samples to the extent that different sizes of bottles would render different final cell numbers after growth. Since we have not observed any volumetric “bottle effect” in our work, we can only speculate on the possible reasons why this has been observed previously. One explanation may be that glassware contaminated with organic carbon can contribute to the perception of a volumetric “bottle effect,” as large surface-to-volume ratios (found in small bottles) would account for increased contamination compared to that in bottles with smaller ratios. Hence, more additional available carbon would be introduced into smaller bottles, giving rise to higher final cell numbers after growth. In this context, it is essential that a comprehensive glassware-cleaning protocol be followed, including heating to a high temperature (>500°C) and storage away from volatile organics (6). In addition, it is important that such experiments at low carbon concentrations are complemented with the inclusion of correct and sensitive controls to assess potential organic carbon contamination. For example, the use of deionized water as a negative control should be avoided, since the absence of inorganic nutrients is bound to lead to no growth and thus false-negative results (10). A good negative control would be water that is only carbon limited, e.g., bottled drinking water (17). Moreover, the use of multiple tools for analyzing growth, including cultivation-independent methods, is encouraged.In conclusion, we did not observe evidence of a volumetric bottle effect on short-term (<5-day) batch incubations. The findings of this study suggest that reference to the so-called volumetric bottle effect should be considered carefully unless supported by clear experimental data. This study does not dispute the fact that many authors have observed results implying apparent bottle effects during growth studies, but it questions the interpretation and understanding of this concept and the random use of the term “bottle effect” to explain uncertainty in results, specifically in relation to bottle size. Hopefully, these data will assist with experimental setups and comparison of data among different groups and stimulate discussion of and future research on this interesting, but slightly controversial, topic.