Antimitotische Aktivität von Methylbenzimidazol-2-ylcarbamat (MBC)

Zusammenfassung Die unbeeinflußte Mitose vonAspergillus nidulans entspricht in zahlreichen ultrastrukturellen Details der Mitose anderer Asco- und Basidiomyceten. Unter dem Einfluß von 4 M MBC sind folgende Parameter der morphometrischen Analyse des Zellkern und des Kern-assoziierten Organells (NAO) verändert: 1. Es werden keine Mikrotubuli gebildet. 2. Das NAO ist extrem vergrößert und fragmentiert in zwei gleiche Teile, die sich auf der Kernhülle entlang bewegen und sich später teilen können. 3. Das Kernvolumen hat sich beträchtlich vergrößert. — Es wird diskutiert, ob MBC einen spezifischen Typ der NAO-Duplikation verursacht und sich die Zellkerne ohne Mikrotubuli teilen.

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Antimitotic activity of methylbenzimidazol-2-ylcarbamate (MBC)II. Electronmicroscopical investigations on duplication of the nucleus-associated organelle (centriolar plaque, MTOC, KCE) inAspergillus nidulans

Summary The unaffected mitosis ofAspergillus nidulans corresponds in many ultrastructural details with the mitosis of other asco- and basidiomycetes. Under the influence of 4 M MBC the following parameters are altered as shown by morphometric analysis of both nucleus and nucleus-associated organelle (NAO): 1. No microtubules are formed. 2. The NAO is extremely enlarged and fragments into two equal parts which move along the nuclear envelope and may divide another time. 3. The nuclear volume is considerably increased.—It is discussed whether MBC causes a specific type of NAO-duplication and nuclei can divide without microtubules.

Meinem Lehrer Prof. M. Girbardtzum 60. Geburtstag gewidmet     

Synthesis and in vitro antimicrobial activity of new 4-phenyl-5-methyl-4H-1,2,4-triazole-3-thione derivatives

This study presents the synthesis, spectral analysis and antimicrobial evaluation of a new series of substituted 1,2,4-triazole (5a–i) and 1,3,4-thiadiazole derivatives (9a, c, g, h). New compounds were obtained by cyclization reaction of acyl thiosemicarbazide derivatives in the presence of alkaline and acidic media. All synthesized compounds were screened for their in vitro antimicrobial activities. Nine of the compounds had potential activity against Gram-positive bacteria (MIC?=?3.91–500 µg/mL). Some compounds showed good activity especially against: Micrococcus luteus ATCC 10240 (MIC?=?3.91?31.25 µg/mL), Bacillus subtilis ATCC 6633 (MIC?=?15.63? 62.5 µg/mL), and Staphylococcus aureus ATCC 25923 (MIC?=?15.63?125 µg/mL).     

Study of the inhibitory effect of Quercus Coccifera's aqueous extract on Staphylococcus aureus and Pseudomonas aeruginosa In vitro

The use of therapeutic herbs has become of great importance these days due to the increase in drug resistance. From a long time ago the Venus'' navel plant has been used to treat infections. In this study the antibacterial effect of the aqueous extract from the Quercus coccifera (jaft) herb, under laboratory conditions. This study was carried out experimentally. After collecting the Venus navel herb, it was dried in a warm dry environment away from direct sunlight in the shade. The alcoholic extract was prepared using a standard method. Clinical samples of staphylococcus aureus and pseudomonas aeruginosa were acquired from Ilam''s health care institutes. The inhibitory effect of the extracts was analysed in the Mueller Hinton using the disk diffusion method for both bacteria. Then MIC and MBC of the extracts was determined using the Macro broth dilution method. At its highest concentration the aqueous extract had an inhibition zone of 27.2 and 23.7 mm on staphylococcus aureus and pseudomonas aeruginosa consecutively. The MIC and MBC for staphylococcus aureus were 10 and 12.5 µg/ml and for pseudomonas aeruginosa they were 10 and 17.5 µg/m consecutively. The results of this study show the strong antimicrobial effect of jaft''s aqueous extract on staphylococcus aureus and pseudomonas aeruginosa and if more studies are based on this topic it could be a substitute for common antibiotics.     

Dual mechanism of bacterial lethality for a cationic sequence-random copolymer that mimics host-defense antimicrobial peptides

Flexible sequence-random polymers containing cationic and lipophilic subunits that act as functional mimics of host-defense peptides have recently been reported. We used bacteria and lipid vesicles to study one such polymer, having an average length of 21 residues, that is active against both Gram-positive and Gram-negative bacteria. At low concentrations, this polymer is able to permeabilize model anionic membranes that mimic the lipid composition of Escherichia coli, Staphylococcus aureus, or Bacillus subtilis but is ineffective against model zwitterionic membranes, which explains its low hemolytic activity. The polymer is capable of binding to negatively charged vesicles, inducing segregation of anionic lipids. The appearance of anionic lipid-rich domains results in formation of phase-boundary defects through which leakage can occur. We had earlier proposed such a mechanism of membrane disruption for another antimicrobial agent. Experiments with the mutant E. coli ML-35p indicate that permeabilization is biphasic: at low concentrations, the polymer permeabilizes the outer and inner membranes; at higher polymer concentrations, permeabilization of the outer membrane is progressively diminished, while the inner membrane remains unaffected. Experiments with wild-type E. coli K12 show that the polymer blocks passage of solutes into the intermembrane space at high concentrations. Cell membrane integrity in E. coli K12 and S. aureus exhibits biphasic dependence on polymer concentration. Isothermal titration calorimetry indicates that the polymer associates with the negatively charged lipopolysaccharide of Gram-negative bacteria and with the lipoteichoic acid of Gram-positive bacteria. We propose that this polymer has two mechanisms of antibacterial action, one predominating at low concentrations of polymer and the other predominating at high concentrations.     

Potential impacts of climate warming on active soil organic carbon contents along natural altitudinal forest transect of Changbai Mountain

Understanding soil carbon fractions and their responses to the global warming is important for improving soil carbon management of natural altitudinal forest ecosystem. In this study, the contents of soil total organic carbon (SOC), soil labile organic carbon (LOC), and microbial biomass carbon (MBC) in soil upper layers (0–20 cm) were measured along a natural altitudinal transect in the north slope of Changbai Mountain. The results showed that under natural conditions the contents of SOC and LOC were largest in Betula ermanii forest (altitude 1996 m), moderate in spruce-fir forest (altitude 1350 m), and smallest in Korean pine mixed broad-leaf tree forest (altitude 740 m). MBC contents in different forest ecosystems decreased in the order of Betula ermanii forest, Korean pine mixed broad-leaf tree forest, and dark coniferous forest. In addition, the responses of SOC, LOC, and MBC to soil warming were conducted by relocating intact soil cores from high- to low-elevation forests for one year. As expected, the soil core relocation caused significant increase in soil temperature but made no significant effect on soil moisture. After one year incubation, soil relocation significantly decreased SOC contents, whereas the contents of LOC, MBC, and the ratios of LOC to SOC and MBC to SOC increased.     

Contrasting effects of maize residue,coal gas residue and their biochars on nutrient mineralization,enzyme activities and CO2 emissions in sandy loess soil

Mismanagement of crop straw and coal gas residue threatens the atmosphere and the economy. Nevertheless, thermal-pyrolysis is an option for management that turns bio-waste into biochar; its viability and adoption by the public as soil amendments is dependent on the agronomic and environmental values compared between biochar and the raw materials. We undertook a 60-day short-term analysis to assess the impact of various wastes and biochars, as well as inorganic nutrients (N), on carbon dioxide (CO₂) fluxes, soil enzyme activities, soil fertility status, and microbial activities. There were eight treatments of soil amendments: without an amendment (CK), Nutrients (N), straw + nutrients (S+N), straw biochar + nutrients (SB+N), coal gas residue + nutrients (C+N), coal gas residue biochar + nutrients (CB+N), straw + straw biochar + nutrients (S+SB+N) and coal gas residue waste + coal gas residue biochar + nutrients (C+ CB +N). The results indicated that soil EC, pH, nitrate N (NO₃^–- N), SOC, TN and available K were significantly (p < 0.05) increased coal gas residue biochar and combined with coal fly ash as compared to maize straw biochar and combined with maize straw and N treatments. The higher concentrations of soil MBC and MBN activities were increased in the maize straw application, while higher soil enzyme activity such as, invertase, urease and catalase were enhanced in the coal fly ash derived biochar treatments. The higher cumulative CO₂ emissions were recorded in the combined applications of maize straw and its biochar as well as coal gas residue and its biochar treatment. Our study concludes, that maize straw and coal fly ash wastes were converted into biochar product could be a feasible substitute way of discarding, since land amendment and decreased CO₂ fluxes and positive changes in soil microbial, and chemical properties, and can be confirmed under long-term conditions for reduction of economical and environment issues.     

Potential impacts of climate warming on active soil organic carbon contents along natural altitudinal forest transect of Changbai Mountain

Understanding soil carbon fractions and their responses to the global warming is important for improving soil carbon management of natural altitudinal forest ecosystem. In this study, the contents of soil total organic carbon (SOC), soil labile organic carbon (LOC), and microbial biomass carbon (MBC) in soil upper layers (0–20 cm) were measured along a natural altitudinal transect in the north slope of Changbai Mountain. The results showed that under natural conditions the contents of SOC and LOC were largest in Betula ermanii forest (altitude 1996 m), moderate in spruce-fir forest (altitude 1350 m), and smallest in Korean pine mixed broad-leaf tree forest (altitude 740 m). MBC contents in different forest ecosystems decreased in the order of Betula ermanii forest, Korean pine mixed broad-leaf tree forest, and dark coniferous forest. In addition, the responses of SOC, LOC, and MBC to soil warming were conducted by relocating intact soil cores from high- to low-elevation forests for one year. As expected, the soil core relocation caused significant increase in soil temperature but made no significant effect on soil moisture. After one year incubation, soil relocation significantly decreased SOC contents, whereas the contents of LOC, MBC, and the ratios of LOC to SOC and MBC to SOC increased.     

Dynamics of soil organic carbon and soil fertility affected by alfalfa productivity in a semiarid agro-ecosystem

We explore the dynamics of soil organic carbon of various forms and its relation with soil fertility in seeded alfalfa grassland established using a field micro-catchment technique to harvest water on the semiarid Loess Plateau in China. Five regimes were set up: (1) conventional flat cultivation without mulch (CK), (2) ridges and furrows were set up alternately on flat land, with 15 cm between each so that the distance between successive ridges (or successive furrows) was 30 cm, and the ridges were mulched with plastic film (M30), (3) similar to M30, but with twice the distance between furrows and ridges (M60), (4) similar to M30, but the ridges were not mulched (B30), (5) similar to M60, but the ridges were not mulched (B60). The increase in alfalfa forage yield in the mulch regimes promotes soil organic carbon (SOC) content, the light fraction of organic carbon (LFOC), the heavy fraction of organic carbon (HFOC) and microbial biomass carbon (MBC). MBC was significantly higher in M30 and M60 than in the other regimes. Significant positive correlation is found between MBC and LFOC (R=0.89; P<0.0001), and MBC and HFOC (R=0.82; P=0.00016). At the end of our three-year experiment, the C/N ratio of 10.09 in M60 was significantly (P<0.005) higher than the other regimes. Since a lower C/N ratio accelerates SOC decomposition in this region, the higher C/N ratio in M60 could limit mineralization of soil nitrogen, conserving soil nitrogen and SOC. The lower ratio of nitrate and nitrite nitrogen to total nitrogen, of 10.74, in M60 at the end of this experiment than in the other regimes and before sowing supports this point. The correlations of SOC with available P and with the ratio of available P to total P are positive in the dry year of 2001, but negative in the wet year of 2002. This can be explained on the basis that a high forage yield of alfalfa requires more soil available P in the wet years than in the dry years.     

Lobaplatin-based regimens outperform cisplatin for metastatic breast cancer after anthracyclines and taxanes treatment

The goal of this study was to assess the antitumor efficacy and safety of lobaplatin-based regimens as the second line of treatment in patients with metastatic breast cancer (MBC) resistant to anthracyclines and taxanes, compared with that of cisplatin-based regimens. During August 2012 to April 2015, 87 patients who received lobaplatin-based regimens or cisplatin-based regimens were included. Medical records of the patients noted that lobaplatin (30?mg/m²) or cisplatin (25?mg/m²), combined with another chemotherapeutic agent such as Gemcitabine (1000?mg/m²) or Vinorelbine (25?mg/m²), was intravenously given to the patients on a basis of twenty-one days as one treatment cycle. All the patients were followed until August 2017. The endpoint of this study was progression-free survival (PFS), overall survival (OS), and estimated objective response rate (RR). Safety and drug tolerability data were also obtained. Lobaplatin-based regimens prolonged PFS compared to cisplatin-based regimens (median 13.2 vs 4.7?months, hazard ratio?=?0.37, 95% confidence intervals: 0.21–0.67, P?=?.0007), while OS was not significantly different between the two groups (hazard ratio?=?0.72, 95% confidence intervals: 0.40–1.30, P?=?.2767), as was objective RR (37.8% vs 33.4%, $x^2$ = 0.19, P?=?.6653). Nausea/vomiting and renal injury were more frequent with cisplatin-based regimens. Our results show that lobaplatin-based regimens are superior to cisplatin in terms of efficacy and are better tolerated.     

Antibacterial activity of selected medicinal plants of northwest Pakistan traditionally used against mastitis in livestock

The present study aimed to investigate the efficacy of traditionally used anti-mastitis plants (Allium sativum, Bunium persicum, Oryza sativa and Triticum aestivum) in northwest Pakistan against bacterial pathogens. Selected plants were phytochemically screened for Alkaloids, Flavonoids, and Saponins and checked for in vitro antibacterial activity at concentration of 50 mg/ml against S. aureus, E. coli and K. pneumoniae by agar well diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration was determined against multidrug resistant bacteria using tube dilution method. All extracts were found to significantly inhibit (p < 0.01, p < 0.05) the activity against bacterial strains examined. Among phytochemicals, alkaloids of all tested antimastitis plants produced significantly higher inhibition zones against bacteria. The minimum inhibitory concentration and minimum bactericidal concentration of phytochemicals and crude methanolic extracts against tested bacterial strains ranged between 12.5–50 mg/ml and 25–50 mg/ml, respectively. Medicinal plants traditionally used against mastitis are therapeutically active against bacterial pathogens. A. sativum and B. persicum were found to be potential candidate species for the development of novel veterinary drugs with low cost and fewer side effects.