TOF-SIMS imaging of chlorhexidine-digluconate transport in frozen hydrated biofilms of the fungus Candida albicans

The diffusion of the anti-microbial chlorhexidine digluconate (CHG) has been studied in C. albicans biofilms by time-of-flight secondary-ion mass spectrometry (TOF-SIMS). C. albicans has been shown to become resistant to common anti-microbial agents, including CHG, when growing as a biofilm. Mass transport resistance within biofilms has commonly been suggested as a resistance mechanism, but measurement of transport for most anti-microbial agents in biofilms has proven extremely difficult because of the heterogeneity of the biofilms and the difficulty in detecting these agents within an intact biofilm. In this study, TOF-SIMS has been used to study the transport of CHG and glucose in a frozen hydrated biofilm. The TOF-SIMS images reveal a progression of CHG from the top of the biofilm to its base with time. Images suggest that there are channels within the biofilm and show preferential binding of CHG to cellular components of the biofilm. Additionally, both living and dead cells can be identified in the TOF-SIMS images by the sequestration of K⁺ and the presence of cell markers. This study demonstrates that TOF-SIMS has the unique potential to simultaneously observe the presence of an antimicrobial agent, concentration of nutrients, and the viability of the cell population.     

Microcalorimetric measurements of the metabolic activity by bacteria and fungi in some Brazilian soils amended with different organic matter

The effect of bacterial and fungal activities on organic matter degradation in Brazilian soils was studied by a microcalorimetric method. Bacteria and fungi isolated from tropical soils and added to: Rhodic eutrudox (R), Typic eutrudox (V) and Quartzipsamment (Q) soils amended separately with moisture (control) (A) and 25% of cattle manure (E), municipal refuse compost (L), earthworm casts (H) or 23 μg of trifluralin (T) were investigated. The number of colony forming units in soil suspension was quantified by microscopy and inoculated in respective soil. All processes were measured at intervals of 7 days over a period of 35 days. The exothermic thermal effect (μJ) per cm³ of bacteria or fungi per gram of dry soil, respectively, for each substrate was: [(9±1), (4±1)] RA; [(478±24), (105±5)] RE; [(121±6), (71±4)] RL; [(121±6), (71±4)] RH; [(8±1); (3±1)] RT; [(10±1), (9±1] VA; [(347±17), (261±13)] VE; [(71±4), (28±1)] VL; [(22±1), (33±2)] VH; [(7±1), (10±1)] VT; [(19±1), (12±1)] QA; [(1301±65), (46±2)] QE; [(89±4), (9±1)] QL; [(130±7), (11±1)] QH; [(32±2), (8±1)] QT. The calorimetric values are higher for bacteria than for fungi. In general, the results showed higher activities in the soil amended with cattle manure than with other additives.     

Unusual Spirodecane Sesquiterpenes and a Fumagillol Analogue from Cordyceps ophioglossoides

Investigation of the cultured mycelia of Cordyceps ophioglossoides resulted in the isolation and characterization of three new unusual spiro[4.5]decane sesquiterpenes, cordycepol A ( 1 ), cordycepol B ( 2 ), and cordycepol C ( 3 ), and a new fumagillol analogue, cordycol ( 4 ). Their structures were established by spectroscopic means. The cytotoxic activities were also evaluated, compounds 3 and 4 showing their IC₅₀ values in the range of 12–33 μg/ml against HeLa and HepG2 (Table 3). In addition, 3 and 4 were not obviously harmful towards normal liver cell lines LO2, showing IC₅₀ values above 80 μg/ml.     

Overview of cationic phthalocyanines for effective photoinactivation of pathogenic microorganisms

Phthalocyanine (Pc) dyes are photoactive compounds that can absorb and emit light in a large range of the UV–vis spectrum, with recognized potential for medical applications. Considering the low solubility of Pc macrocycles in water, it is important to use cationic symptoms on their skeleton to improve their amphiphilicity for biomedical applications. The use of suitable pyridinium groups on Pc is a good strategy to solve this drawback and make them more eff ;ective to photoinactivate microorganisms via a photodynamic inactivation (PDI) approach. This review focuses the synthesis of quaternized Pc dyes, their photophysical and photochemical properties, and their antimicrobial photoinactivation efficiency. This innovative study compares, for the first time, different cationic moieties on Pc taking into account the efficiency of singlet oxygen (¹O₂), quantum yield (Φ_Δ) generation, fluorescence quantum yield (Φ_F), (photo)stability, light irradiation type (visible/white and/or red light), maximized overlapped absorption effect of Pc (S- and/or Q-band) vs light system irradiation type, and water solubility (n-octanol/water partition coefficient, P_o/w), when these parameters are determined and provided in the multidisciplinary reports. This approach is also relevant to conjugate free-base (H₂Pc) and metalated phthalocyanines (MPc, M = Zn²⁺, Mg²⁺, In³⁺, Ga³⁺, Ge³⁺, Si⁴⁺, etc.) with aromatic or aliphatic substituents linked by N, O or S atoms on the peripheral or axial positions of the Pc structures, such as e.g. (methoxy, oxy, or thio)pyridinium, ammonium, or benzimidazolium units, etc. Here, the influence of the structural peripheral (α- and/or β-position of Pc) or axial substituents type, number and positive charge position that can affect the PDI process will be analysed. These aspects are important to design versatile molecules that can interact with pathogenic microorganisms of variable size, subcellular architecture, biochemical composition, and susceptibility to externally added chemical agents. This review highlights the important developments of several modifications of cationic Pc dyes for the PDI of microorganisms, such as pathogenic bacteria, fungi, and virus.     

Degradation of Amino-(3-methoxyphenyl)methanephosphonic Acid by Alternaria sp

Alternaria sp. isolated from the surface of carrot ( Daucus carota ) seeds appeared to be able to degrade amino-(4-methoxyphenyl)-methanephosphonic acid using it as a sole source of carbon, nitrogen, and phosphorus for growth.     

Oleanane‐Type Triterpenoids from the Endophytic Fungus Pestalotiopsis clavispora Isolated from the Chinese Mangrove Plant Bruguiera sexangula

Three new triterpenoid derivatives, named (15α)‐15‐hydroxysoyasapogenol B ( 1 ), (7β,15α)‐7,15‐dihydroxysoyasapogenol B ( 2 ), and (7β)‐7,29‐dihydroxysoyasapogenol B ( 3 ), were isolated from cultures of the plant endophytic fungus Pestalotiopsis clavispora. Their structures and relative configurations were elucidated by extensive spectroscopic analysis and X‐ray crystallography.     

Dependence of fungal biodegradation of PEG/castor oil-based polyurethane elastomers on the hard-segment structure

In the context of protecting of the environment, this work studies the biodegradation of PEG-based polyurethane elastomer films in the presence of the soft rot fungus Chaetomium globosum, determined via the Petri-dish test. Using PEG with high-molecular weight (MW = 1500) as a chain extender led to polyurethane elastomers with lower physical crosslink density and higher swelling rates. The structural modifications in the hard-segment area (CO and N-H peaks) are considerable and were analyzed by FTIR spectroscopy. Biodegradation lowers the final mechanical properties, but increases yield points, especially in the case of polyurethane elastomers crosslinked with castor oil. Polyurethane elastomer samples showed visible degradation proved by the mechanical weakening of the films. Thus, breaking strains decrease from 670-1180% to 500-680% and tensile strengths decreased from 11.5-27.5 MPa to 4-11.5 MPa after 130 days of fungal biodegradation. The changes in the morphology of the polyurethane films surface were analyzed by SEM and have been found to exhibit increasing porous structure and fungal hyphae. The effects of the hard-segment composition of the polyurethane elastomers on the fungal biodegradation behaviour were investigated.     

菌类多糖链构象及其表征方法研究进展 （专题报道）

 概述了菌类多糖在溶液中链构象及其表征方法的研究进展.主要报道从各种真菌（香菇、茯苓、灵芝、木耳、黄单胞菌、裂褶菌等）中提取的多糖在溶液中的分子量、分子形态和尺寸,即链构象.同时介绍多糖链构象对生物活性的影响,并且指出多糖刚性链带电基团及适量分子量有利于促进它与免疫细胞上受体结合,从而抑制肿瘤细胞增殖.由此表明,多糖链构象的研究对弄清其生物功能和推动生命科学发展十分重要.多糖在溶液中主要以无规线团、双螺旋、三螺旋、蠕虫状、棒状链以及聚集体构象存在,它取决于单糖组成、糖苷键、支链结构以及分子内和分子间作用力.测定链构象的方法主要包括光散射、黏度、显微技术（透射电镜,扫描电镜以及原子力显微镜）、微量热法和小角X-射线散射等.此外,介绍了多糖溶液理论以及计算链构象参数的表达式.     

Modeling and analysis of the removal of an organic pollutant from a water body using fungi

In this paper, a non linear mathematical model for removing an organic pollutant such as a dye from a water body is proposed and analyzed. In the modeling process four variables are considered, namely, (i) the concentration of the dye, (ii) the density of fungus population, (iii) the concentration of a nutrient and (iv) the concentration of dissolved oxygen (DO). It is assumed that an organic pollutant is present in water with given concentration or discharged with a constant rate in water. It is assumed further that fungus population is kept alive and active due to supply of a nutrient. It is considered that nutrient and oxygen are supplied to the water body from outside with constant rates. The model is analyzed by using the stability theory of differential equations. The model analysis shows that organic pollutant can be removed from the water body by fungus population and the level of degradation depends upon the concentration of organic pollutant, the density of fungal population and the interaction processes involved.The simulation analysis of the proposed model confirms the analytical results. It is also found that these results are qualitatively in line with the experimental observations of one of the authors (Sanghi).     

ICP-A ES法测定中国不同产地绒柄牛肝菌中矿质元素含量

采用微波消解处理样品,以电感耦合等离子体发射光谱法（IC P-A ES ）测定了采自云南省不同地点的绒柄牛肝菌菌盖和菌柄中的12种矿物质元素（P ,Na ,Ca ,Cu ,Fe ,Mg ,Zn ,As ,Cd ,Co ,Cr ,Ni）含量。结果显示：绒柄牛肝菌中P ,Ca ,Mg ,Fe ,Zn ,Cu的含量较高,其中菌盖中的P ,Mg ,Zn ,Cd较高,而菌柄中的Ca ,Co ,Ni较高;聚类分析结果显示,采用普洱地区的样品与其他地区的样品差异较大;主成分分析结果显示,前三个主成分的累计贡献率为77％,其中第一主成分中的P ,Ca ,Cu ,Fe ,Mg ,As ,第二主成分中的Ni ,Na以及第三主成分中的Cd和Zn对区分不同地点的样品贡献较大。结果表明采自不同生境地的食用菌元素含量差异较大。