scholarly journals Effects of mixing intensity on colony size and growth of Microcystis aeruginosa

Author(s):  
Zhong Chunni ◽  
Yang Guijun ◽  
Qin Boqiang ◽  
Steven W. Wilhelm ◽  
Liu Yu ◽  
...  

Mixing is an integral environmental factor that affects lake ecosystems. For the cyanobacterium Microcystis, colony size is important with respects to migration velocity, how cells respond to grazing pressure, light attenuation, nutrient uptake and growth. To understand how mixing shapes colony size and the growth of Microcystis, we measured the effects of different current velocities (0, 0.16, 0.32, 0.64, and 1.28 m s−1) on M. aeruginosa in Lake Taihu. After 24 h of continuous mixing, the mean colony sizes of M. aeruginosa in the controls, 0.16, 0.32, 0.64, and 1.28 m s−1 groups were 23.6, 50.1, 92.9, 67.8, and 37.3 μm, respectively. Colony sizes of M. aeruginosa in all treatment groups were significantly larger than those in controls. As well, the concentration of soluble extracellular polysaccharide and bound extracellular polysaccharides of M. aeruginosa in all treatment groups were significantly higher than those in controls. Except for the highest level of mixing (1.28 m s−1), the growth rate of M. aeruginosa was significantly higher than that in controls. This study suggested that mixing intensity over short time periods can significantly influence colony size and the growth of M. aeruginosa.

Author(s):  
Ch. Ravi Teja ◽  
Abraham P. Karlapudi ◽  
Neeraja Vallur ◽  
K. Mamatha ◽  
D. John Babu ◽  
...  

Abstract Background Extracellular polysaccharides (ECPs) produced by biofilm-producing marine bacterium have great applications in biotechnology, pharmaceutical, food engineering, bioremediation, and bio-hydrometallurgy industries. The ECP-producing strain was identified as Acinetobacter indicus M6 species by 16S rDNA analysis. The polymer produced by the isolate was quantified and purified and chemically analyzed, and antioxidant activities have been studied. The face-centered central composite design (FCCCD) was used to design the model. Results The results have clearly shown that the ECP was found to be endowed with significant antioxidative activities. The ECP showed 59% of hydroxyl radical scavenging activity at a concentration of 500 μg/mL, superoxide radical scavenging activity (72.4%) at a concentration of 300 μg/mL, and DPPH˙ radical scavenging activity (72.2%) at a concentration of 500 μg/mL, respectively. Further, HPLC and GC-MS results showed that the isolated ECP was a heteropolymer composed of glucose as a major monomer, and mannose and glucosamine were minor monomers. Furthermore, the production of ECP by Acinetobacter indicus M6 was increased through optimization of nutritional variables, namely, glucose, yeast extract, and MgSO4 by “Response Surface Methodology”. Moreover the production of ECP reached to 2.21 g/L after the optimization of nutritional variables. The designed model is statistically significant and is indicated by the R2 value of 0.99. The optimized medium improved the production of ECP and is two folds higher in comparison with the basal medium. Conclusions Acinetobacter indicus M6 bacterium produces a novel and unique extracellular heteropolysaccharide with highly efficient antioxidant activity. GC-MS analyses elucidated the presence of quite uncommon (1→4)-linked glucose, (1→4)-linked mannose, and (→4)-GlcN-(1→) glycosidic linkages in the backbone. The optimized medium improved the production of ECP and is two folds higher in comparison with the basal medium. The newly optimized medium could be used as a promising alternative for the overproduction of ECP.


Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 273
Author(s):  
Marc Schargus ◽  
Catharina Busch ◽  
Matus Rehak ◽  
Jie Meng ◽  
Manuela Schmidt ◽  
...  

The aim of this study was to compare the efficacy of trabeculectomy (TE), single XEN microstent implantation (solo XEN) or combined XEN implantation and cataract surgery (combined XEN) in primary open-angle glaucoma cases, naïve to prior surgical treatment, using a monocentric retrospective comparative cohort study. Intraocular pressure (IOP) and the number of IOP-lowering drugs (Meds) were monitored during the first 24 months after surgery. Further disease progression was monitored using peripapillary retinal nerve fiber layer (RNFL) thickness examinations using spectral domain optical coherence tomography (OCT) as well as visual acuity (VA) and visual field (VF) tests. In the TE group (52 eyes), the mean IOP decreased from 24.9 ± 5.9 to 13.9 ± 4.2 mmHg (p < 0.001) and Meds decreased from 3.2 ± 1.2 to 0.5 ± 1.1 (p < 0.001). In the solo XEN (38 eyes) and the combined XEN groups, the mean IOP decreased from 24.1 ± 4.7 to 15.7 ± 3.0 mmHg (p < 0.001) and 25.4 ± 5.6 to 14.7 ± 3.2 mmHg (p < 0.001), while Meds decreased from 3.3 ± 0.8 to 0.8 ± 1.2 (p < 0.001) and 2.7 ± 1.2 to 0.4 ± 1.0 (p < 0.001), respectively. The VF and VA indices showed no sign of further deterioration, the RNFL thickness further decreased in all treatment groups after surgery. TE and XEN led to comparable reductions in IOP and Meds. Although the VA and VF indices remained unaltered, the RNFL thickness continuously decreased in all treatment groups during the 24-month follow-up.


1992 ◽  
Vol 38 (8) ◽  
pp. 857-861 ◽  
Author(s):  
Michael F. Dunn ◽  
Arthur L. Karr

Thirty-four strains of Bradyrhizobium japonicum were screened for the in vitro production of an extracellular polysaccharide depolymerase active against the B. japonicum acidic extracellular polysaccharide that contains mannose, glucose, galactose, and 4-O-methylgalactose as neutral sugar components. Over 90% of tested strains producing this type of extracellular polysaccharide also produced the extracellular polysaccharide depolymerase, whereas strains producing a compositionally different extracellular polysaccharide did not. In addition, representatives of species related to B. japonicum by extracellular polysaccharide composition or host range were also phenotypically depolymerase negative. Depolymerase was also present in soybean root nodules formed by B. japonicum strain 2143. In contrast to the cell-associated depolymerase activity found in free-living cells of this strain, most of the depolymerase activity present in nodules is free of the bacteroids. The widespread occurrence of the depolymerase among B. japonicum strains and the spatiotemporal distribution of its activity in planta are consistent with the enzyme playing a role in the removal of surface extracellular polysaccharide from the microorganism during the infection of nodulation process. Key words: Bradyrhizobium japonicum, soybean, extracellular polysaccharides, extracellular polysaccharide depolymerase, bacteroids.


2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Anna Bilska-Wilkosz ◽  
Magdalena Kotańska ◽  
Magdalena Górny ◽  
Barbara Filipek ◽  
Małgorzata Iciek

The exogenous lipoic acid (LA) is successfully used as a drug in the treatment of many diseases. It is assumed that after administration, LA is transported to the intracellular compartments and reduced to dihydrolipoic acid (DHLA) which is catalyzed by NAD(P)H-dependent enzymes. The purpose of this study was to investigate whether LA can attenuate cardiovascular disturbances induced by ethanol (EtOH) and disulfiram (DSF) administration separately or jointly in rats. For this purpose, we measured systolic and diastolic blood pressure, recorded electrocardiogram (ECG), and estimated mortality of rats. We also studied the activity of aldehyde dehydrogenase (ALDH) in the rat liver. It was shown for the first time that LA partially attenuated the cardiac arrhythmia (extrasystoles and atrioventricular blocks) induced by EtOH and reduced the EtOH-induced mortality of animals, which suggests that LA may have a potential for use in cardiac disturbance in conditions of acute EtOH intoxication. The administration of EtOH, LA, and DSF separately or jointly affected the ALDH activity in the rat liver since a significant decrease in the activity of the enzyme was observed in all treatment groups. The results indicating that LA is an inhibitor of ALDH activity are very surprising.


2020 ◽  
Vol 3 (1) ◽  
pp. 48-56
Author(s):  
Rika Puspita Sari

Bangun-bangun leaves and palm leaves contain various secondary metabolites such as tannins, alkaloids and flavonoids which can healing wound. The aim of this study was to determine the effect of ointment combination of ethanol extract of leaves of bangun- bangun (Coleus amboinicus Lour.) And ethanol extract of palm leaves (Elaeis guineensis Jacq.) In healing wound. The bangun- bangun leaves and the palm leaves are separated from the petiole and then dried in a drying cupboard so that it becomes a simplisia. Simplisia is extracted by maceration method then evaporated with a rotary evaporator and evaporated again on a water bath to produce a thick extract. Thick extracts from the leaves of bangun- bangun and palm leaves are then formulated into ointment preparations with varying concentrations. Each rabbit was shaved on its back then cleaned with 70% alcohol. Furthermore, rabbits were anesthetized using 0.5 ml Lidocain HCL as much as 0.5 ml subcutaneously. Next mark the part that will be injured with a diameter of 2 cm, by lifting the rabbit skin using tweezers and then made a wound using surgical scissors that have been sterilized first with 70% alcohol. Wound diameter measurements showed that all treatment groups from day 1 to day 23 experienced changes in wound diameter. The combination ointment of ethanol extract of leaves wake-up (EEDB) 10% and ethanol extract of palm oil leaves (EEDKS) 10% have a more effective effect in wound healing than single dose.


2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S356-S357
Author(s):  
Nellie Darling ◽  
Kristen R Kent ◽  
Gavin Clark ◽  
Xue Geng ◽  
Marybeth Kazanas ◽  
...  

Abstract Background Treatment strategies for COVID-19 have evolved based on clinical trials. We performed a retrospective analysis to determine treatment outcomes for Remdesivir (RDV), Tocilizumab (TOCI), and/or Dexamethasone (DEX) in a representative population from the Mid-Atlantic region. Methods A retrospective chart review was performed for patients admitted to MedStar hospitals within the D.C./Baltimore corridor from 03/01/2020 to 12/31/2020, and diagnosed with COVID-19 using a NP SARS-CoV-2 RT PCR assay. The MedStar Pharmacy Database was utilized to stratify based on any combination of RDV, TOCI, DEX treatment. Our primary endpoints included O2 delivery device, length of stay (LOS), and mortality. Results A total of 2488 patients were included. Overall, the average age of patients was 62yrs, 53% male, and the majority of patients were of Black (54%) or White (27%) race. The average length of stay was 11 days (SD = 12) with a mortality of 14%. Using univariate analyses, all combinations of RDV, TOCI, and DEX treatment regimens were evaluated. Patients who received DEX required the most ventilatory support on Day 1 (5%, p&lt; 0.001) compared to all other groups. These same patients, however, did not go on to have higher ventilatory needs (17%, p&lt; 0.001) compared to the group which ultimately required the most ventilatory support, TOCI plus DEX (94%, p&lt; 0.001) at Day 28 of treatment. TOCI use alone was associated with a 4% to 63% (p&lt; 0.001) increase in need for ventilatory support over the course of 28 days (Figure 1). The shortest LOS was seen in those treated with DEX alone (9.5 days, p&lt; 0.001). Longer LOS outcomes were associated with all treatment groups which included TOCI use (19 to 22 days, p&lt; 0.001, Figure 2). Mortality was similarly higher among all treatment groups which contained TOCI (30% to 62.5%, p&lt; 0.001, Figure 3) when compared to those with RDV and/or DEX use alone (10% to 14%, p&lt; 0.001). Barplot of Oxygen Delivery Device at Admission and within 28 Days among Treatments Figure 1. Largest increase in ventilatory support from Day 1 of treatment (left) to Day 28 of treatment (right) was seen among TOCI and DEX (0% to 93.8%), RDV and TOCI (0% to 72.2%) and TOCI alone (3.7% to 63.4%). Figure 2. LOS was higher among all treatments containing TOCI (p&lt;0.001), with the highest being the combination group of RDV, TOCI, and DEX (22.4 days, p&lt;0.001). Figure 3. Treatment regimens containing TOCI accounted for the highest mortality rates as seen in TOCI and DEX use (62.5%), RDV and TOCI (44.4%), and TOCI use alone (30.4%). Conclusion Our study demonstrates that “real-world” clinical outcomes for patients with COVID-19 treated with Remdesivir, Tocilizumab, and Dexamethasone are consistent with what has been reported in clinical trials. The higher mortality associated with Tocilizumab treatment may reflect the use of this agent in critically ill patients with COVID-19. Disclosures Princy N. Kumar, MD, AMGEN (Other Financial or Material Support, Honoraria)Eli Lilly (Grant/Research Support)Gilead (Grant/Research Support, Shareholder, Other Financial or Material Support, Honoraria)GSK (Grant/Research Support, Shareholder, Other Financial or Material Support, Honoraria)Merck & Co., Inc. (Grant/Research Support, Shareholder, Other Financial or Material Support, Honoraria)


2006 ◽  
Vol 58 (3) ◽  
pp. 179-182 ◽  
Author(s):  
Jelena Vukojevic ◽  
Mirjana Stajic ◽  
Sonja Duletic-Lausevic ◽  
Jasmina Simonic

The effect of initial medium pH on biomass, extracellular and intracellular polysaccharide, and ligninolytic enzyme production by Ganoderma lucidum was investigated at different pH values after 7 and 14 days of cultivation. Maximal production of biomass was recorded at pH 4.5 and 5.0; maximal production of extracellular polysaccharides at pH 7.0 and 3.0; and maximal production of intracellular polysaccharides at pH 7.0 and 5.5. Ligninolytic enzymes were not produced at any pH of the medium. Maximal biomass production was obtained on the 11th day of cultivation; maximal extracellular polysaccharide production on the 7th day; and maximal intracellular polysaccharide production on the 6th and 10th day of cultivation. .


Animals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1124
Author(s):  
Hailey Wooten ◽  
Hwanhee Kim ◽  
Amanda R. Rakhshandeh ◽  
Anoosh Rakhshandeh

The purpose of the current study was to determine the best method of delivery for glucocorticoid receptor agonist (GRA) treatment. A total of 167 Pig Improvement Company (PIC) piglets (body weight (BW) 7.35 ± 1.24 kg) were weaned at 25.0 ± 0.81 days of age and randomly assigned to 14 treatment groups based on a 2 × 7 factorial arrangement with sex (gilts vs. barrows), in-feed antibiotic (ANT; 110 mg/kg in-feed tylosin), repeated intramuscular (I.M.) injection of GRA (two injections, 0.2 mg/kg BW dexamethasone (DEX)), low dose in-feed GRA (LF, 2.5 mg/kg diet DEX ), high dose in-feed GRA (HF, 5 mg/kg diet DEX), low dose in-water GRA (LW, 0.8 mg/L DEX ), high dose in-water GRA (HW, 1.6 mg/L DEX ), and no treatment control (CON) as the main factors. Body weight and feed intake were measured daily from days 0 to 7 and weekly from days 7 to 28 post-weaning. The interaction effect for average daily gain (ADG) was significant with gilts performing better in the I.M., ANT, and LF groups (p = 0.05). All treatment groups, with the exception of the HW group, had a higher ADG than the CON group. Gilts in the I.M., LF, and HF groups had the highest ADG compared to other treatment groups (p ≤ 0.05). Sex and the interaction between sex and treatments had no effect on the gain-to-feed ratio (G:F; p ≥ 0.21). All treatment groups had a higher G:F than the CON group (p ≥ 0.04). These results suggest that the low-dose, in-feed GRA treatment is the best GRA delivery method and is a suitable alternative to in-feed sub-therapeutic antibiotics.


2019 ◽  
Vol 97 (12) ◽  
pp. 1124-1131 ◽  
Author(s):  
Aysu Kilic ◽  
Savas Ustunova ◽  
Cansu Usta ◽  
Huri Bulut ◽  
Ismail Meral ◽  
...  

Our study aimed to determine the effects of losartan and PD123319 in ischemia–reperfusion (IR) injury in isolated perfused rat heart. The study used 40 male Wistar albino rats that were grouped as Control, IR, and IR treatment groups that received losartan (20 mg/kg), PD123319 (20 mg/kg), and losartan+PD123319. The hearts were attached to Langendorff isolated heart system by employing in situ cannulation method, and cardiodynamic parameters were recorded during the experiment. At the end of experiment, hearts were retained for biochemical analysis and all data were statistically evaluated. A partial recovery of cardiodynamic parameters was observed in all treatment groups. A significant increase in oxidative stress parameters were seen in the IR group, whereas all treatment groups exhibited lower increase. Furthermore, levels of all antioxidant parameters were significantly lower in the IR group, but higher in the treatment groups. Effects on all parameters were much more remarkable in the PD123319 group. Levels of angiotensin II and renin were increased (P < 0.001) with IR application and decreased (P < 0.001) with the treatment of both antagonists. In conclusion, treatment of losartan and PD123319 played a cardioprotective role against IR injury, PD123319 being more effective in this protection.


Author(s):  
Yunita Sari Pane ◽  
Sufitni Sufitni ◽  
Fitriani Lumongga ◽  
Nurfida Alrasyid ◽  
Dini Permata Sari ◽  
...  

Objective: This study aims to observe the analgesic activity of Bangun-bangun (Coleus amboinicus) leaves by induction of pain arising from chemical excitement after exposure to acetic acid.Methods: The effectiveness test of water extract and ethanol extract of Bangun-bangun leaves as an analgesic was measured by comparing the mean of quantitative and the writhing between control and treatment group. In addition, observations on the decrease in inflammatory processes occurred by calculating the reduction in the number of leukocyte migration to the inflammatory area.Result: The decrease of excitatory pain in all treatment Groups (I-IV) were significantly different. The comparison of mean values ± SEM decreased excitatory pain Groups I-II (255.00±22.22; 88.33±14.58), p=0.000. Groups I-III (255.00±22.22; 60.00±10.04), p=0.000 and Groups I-IV (255.00±22.22; 50.83±3.09), p=0.000. On histopathology examination, all treatment groups were significantly different (p=0.006). The comparison of mean value ± SEM decrease number of leukocyte Groups I-II (31.73±5.22; 14.70±3.71), p=0.025. Groups I-III (31.73±5.22; 15.67±3.22), p=0.036 and Groups I-IV (31.73±5.22; 11.77±2.77), p=0.008. However, the comparison of decrease of excitatory of pain and number of leukocyte migration between each group did not show significantly different (p>0.05).Conclusions: This study concluded that the Bangun-bangun leaves both in the form of water extract and ethanol extract proved efficacious as a pain reliever in the mice after induction of acetic acid.


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