Fertiliser products from new sanitation systems: Their potential values and risks

The plant nutrients consumed in human society today are lost through the established wastewater treatment systems in industrialised countries as well as via insufficient or non-existent handling of sewage in the developing world. New sanitation systems have been designated to overcome this failure. The source separated wastewater streams collected within these systems contain a high nutrient content, and can be used as fertiliser as well as soil conditioner after appropriate storage and/or treatment. Application in agriculture with existing techniques is feasible. However, pathogens and pharmaceuticals contained in these fertiliser types are a potential hazard. Nevertheless, storage and appropriate treatment can minimise the risks. The products deriving from these systems have a high potential to preserve available plant nutrient resources and deficiencies in agriculture as well as being able to substitute synthetic plant nutrients and at the same time prevent unwanted environmental nutrient over-enrichment.     

6289株院内感染病原菌的分布及耐药性研究

目的了解医院内感染的病原菌的分布及耐药状况。方法采用回顾性调查的方法,收集本院2003年至2007年问住院患者的标本,进行病原菌的分离、鉴定及药物敏感试验,同时监测耐甲氧西林葡萄球菌（MRS）及产超广谱β-内酰胺酶（ESBLa）的革兰阴性杆菌。结果所分离的6289株细菌中,G^-菌占71．7％（4510／6289）,G^＋菌占21．3％（1338／6289）,真菌占7．0％（411／6289）;常见的细菌是大肠埃希菌（24．3％）、铜绿假单胞菌（16．6％）、肺炎克雷伯菌（14．3％）、金黄色葡萄球菌（11．3％）及白色假丝酵母菌（6．2％）;细菌主要来自于ICU、神经外科、创伤科;耐药结果显示,G^-菌除对亚胺培南、头孢哌酮／舒巴坦及哌拉西林／他唑巴坦有较低的耐药率外,对常见的抗生素呈现较高的耐药率;金黄色葡萄球菌除对万古霉素及替考拉宁敏感外,对喹诺酮类、四环素类及克林霉素类等呈多重耐药。结论院内感染的病原菌主要以阴性杆菌为主,其次是阳性球菌,真菌感染也有上升的趋势。感染细菌不断增加的耐药性应该加强临床的抗菌药物使用的干预。     

Novel short antibacterial and antifungal peptides with low cytotoxicity: Efficacy and action mechanisms

Short antimicrobial peptides with nine and eleven residues were developed against several clinically important bacterial and fungal pathogens (specifically Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Fusarium solani). Twelve analogues of previously reported peptides BP76 (KKLFKKILKFL) and Pac-525 (KWRRWVRWI) were designed, synthesized, and tested for their antimicrobial activities. Two of our eleven amino acid peptides, P11-5 (GKLFKKILKIL) and P11-6 (KKLIKKILKIL), have very low MICs of 3.1-12.5 μg ml⁻¹ against all five pathogens. The MICs of these two peptides against S. aureus, C. albicans and F. solani are four to ten times lower than the corresponding MICs of the reference peptide BP76. P9-4 (KWRRWIRWL), our newly designed nine-amino acid analogue, also has particularly low MICs of 3.1-6.2 μg ml⁻¹ against four of the tested pathogens; these MICs are two to eight times lower than those reported for Pac-525 (6.2-50 μg ml⁻¹).These new peptides (P11-5, P11-6 and P9-4) also exhibit improved stability in the presence of salts, and have low cytotoxicity as shown by the hemolysis and MTT assays. From the results of field-emission scanning electron microscopy, membrane depolarization and dye-leakage assays, we propose that these peptides exert their action by disrupting membrane lipids. Molecular dynamics simulation studies confirm that P11-6 peptide maintains relatively stable helical structure and exerts more perturbation action on the order of acyl tail of lipid bilayer.     

Biocontrol of Damping-off Diseases Caused by Rhizoctonia solani and Pythium ultimum with Alginate Prills of Gliocladium virens, Trichoderma hamatum and Various Food Bases

Alginate prills were formulated with the biomass of isolates of Gliocladium virens and Trichoderma spp. and various food bases (wheat bran, corn cobs, peanut hulls, soy fiber, castor pomace, cocoa hulls and chitin). Alginate prills with G. virens (Gl-21) biomass and all food bases except cocoa hull meal significantly reduced the damping-off of zinnia in a soil-less mix caused by Rhizoctonia solani and Pythium ultimum. The prills with bran, soy fiber, castor pomace or chitin resulted in stands similar to those in the non-infested control. In soil, prills with all the food bases and Thrichoderma hamatum (TRI-4) biomass controlled the damping-off of cotton caused by R. solani and gave stands comparable to, or better than, those in the non-infested control soil. Prills with all the food bases resulted in a proliferation of Gl-21 in a soil-less mix and of Gl-21 and TRI-4 in soil. Prills with food bases and TRI-4 biomass reduced the survival of R. solani in infested beet seed to less than 30%, with bran and chitin being the most effective food bases; prills with Gl-21 biomass and all food bases also reduced the survival of R. solani in beet seed, but not as much as did prills with TRI-4 biomass. In prills containing wheat bran, soy fiber or chitin, the biocontrol isolate Th-58 (T. harzianum) was almost as effective as TRI-4, but isolate Gl-3 (G. virens) was less effective. There was no significant interaction between the biocontrol fungus and the food base. The results suggest that the intrinsic properties of a selected fungus isolate are more important than some formulation variables in biocontrol.     

Extruded Granular Formulation with Biomass of Biocontrol Gliocladium virens and Trichoderma spp. to Reduce Damping-off of Eggplant Caused by Rhizoctonia solani and Saprophytic Growth of the Pathogen in Soil-less Mix

Extruded granular formulations containing rice flour, gluten, Pyrax, vermiculite, canola oil, and fermentor-produced biomass of isolates of Gliocladium virens (Gl-3, Gl-21 and Gl-32), Trichoderma hamatum (TRI-4 and 31-3), T. harzianum (Th-32 and Th-87) and T. viride (Tv-101) were evaluated for their effect on the reduction of eggplant damping-off caused by Rhizoctonia solani, reduction of pathogen inoculum and proliferation of the isolates in a soil-less mix. Granules with all isolates except 31-3 significantly (P < 0.01) reduced damping-off, and granules with Gl-3, Gl-21, Gl-32, TRI-4 and Th-87 yielded stands comparable to that (90%) of the non-infested control. Granules with isolates Gl-21 and TRI-4 were the most effective in the reduction of saprophytic growth of R. solani, and there was a significant inverse correlation (r ² = - 0.82) between eggplant stand and saprophytic growth of the pathogen over all treatments. Isolate propagules proliferated to about 10⁷ colony-forming units (CFU) g^?1 of soil-less mix after a 6-week incubation, but there was no correlation between the number of CFU and eggplant stand or saprophytic growth reduction of the pathogen. Granules with Gl-21 and TRI-4 amended to pathogen-infested soil-less mix at a rate as low as 0.06% significantly (P < 0.05) reduced damping-off and pathogen saprophytic growth, and a rate of 0.25% of Gl-21 granules resulted in an eggplant stand comparable to that of the non-infested control. There was no significant correlation between the rate of granule amendment and the proliferation of Gl-21 and TRI-4. Granules of Gl-21 and TRI-4 also significantly prevented the spread of R. solani in flats of eggplant seedlings when the biocontrol granules were applied to the soil-less mix 1 day before the pathogen inoculum.     

北京地区养殖果子狸SARS冠状病毒调查

目的调查北京地区养殖果子狸SARS病毒感染和携带情况。方法用PCR方法检测果子狸咽拭子、肛拭子和皮毛标本,进行SARS病毒病原检测;中和抗体检测果子狸血清。结果本次抽样检测北京地区3个养殖场的10%的果子狸,未检测到SARS冠状病毒,血清抗体阴性。结论检测结果不支持北京地区饲养的果子狸中携带有SARS冠状病毒。     

A baseline model for the co-evolution of hosts and pathogens

The basic reproduction ratio (R (0)) is the expected number of secondary cases per primary in a totally susceptible population. In a baseline model, faced with an individual host strain pathogen virulence evolves to maximise R (0) which yields monomorphism. The basic depression ratio (D (0)) is the amount by which the total population is decreased, per infected individual, due to the presence of infection. Again, in a baseline model, faced with an individual pathogen strain host resistance evolves to minimise D (0) which yields monomorphism. With this in mind we analyse the community dynamics of the interaction between R (0) and D (0) and show that multi-strain co-existence (polymorphism) is possible and we discuss the possibility of stable cycles occuring within the co-existence states. We show for co-existence, the number of host and pathogen strains present need to be identical in order to achieve stable equilibria. For polymorphic states we observe contingencies (outcome dependent on initial conditions) between both point equilibrium and sustained oscillations. Invasion criteria for host and pathogen strains are identified.     

Red-Tailed Guenons (Cercopithecus ascanius) and Strychnos mitis: Evidence for Plant Benefits Beyond Seed Dispersal

I report data collected on red-tailed guenon (Cercopithecus ascanius schmidti) fruit processing behaviors between June 1993 and April 1994. Red-tailed guenons consumed the fruit of Strychnos mitis in 542 of 2,930 fruit-eating events (FEEs). The monkeys spat out cleaned seeds of Strychnos mitis in a majority of these records (477/542; 88%); seeds were occasionally swallowed whole, but only when pulp was unripe (69/542; 12%). In 83% of the FEEs on Strychnos, the red-tailed guenons spat out seeds within 10 m of the removal site; they typically stayed in the same tree while processing fruit, and in 56% of the FEEs, they moved <1 m before spitting seeds. I monitored spat seeds to evaluate the impact of monkey fruit processing on seed fate. Results indicate that 83% of seeds spat out by the red-tailed guenons germinated, while only 12% of unprocessed seeds survived to germination (p < 0.01). Of the processed seeds that germinated, 60% survived to germination and seedling establishment, while only 5% of unprocessed seeds survived to seedling establishment (p < 0.01). Unprocessed seeds were also more likely to be attacked by seed predators (p < 0.01) and fungus (p < 0.01). Although there is generally high mortality in seeds/seedlings, mature trees of Strychnos mitis are found in groves of adults, under which dense populations of seedlings and saplings can occur. These data suggest that Strychnos mitis does not conform to expectations of the Janzen-Connell model of seed escape from parent trees. Instead, I suggest that by removing pulp, a process that results in a reduction of fungal pathogen attack, red-tailed guenons positively effect the seed survivorship of Strychnos mitis. Although this effect has been observed in pulp-cleaning ant species, it is a hitherto undescribed effect of primates on their fruit resources.     

Decline of <Emphasis Type="Italic">Cornus florida</Emphasis> and forest succession in a <Emphasis Type="Italic">Quercus–Carya</Emphasis> forest

Cornus florida is a common understory species in many hardwood forests in eastern North America. It plays an important role in nutrient cycling and is an important food resource for many vertebrate species, especially migratory birds. We used data collected over a 16-year period to examine population dynamics of a tagged population of C. florida in a 6.4 ha area in the context of change in the protected Quercus–Carya forest of the Ross Biological Reserve, Indiana. We examined the hypothesis that forest dynamics result from interactions between long-term ecological succession and pathogens. The C. florida population at the Ross Reserve declined by 50% between 1983 and 2000, with a survivorship of 24%. Analysis of 40 years of forest survey data showed that Quercus and Carya populations declined in importance, while Acer saccharum increased dramatically. This change in forest structure is consistent with successional changes occurring throughout the Midwest and can be attributed to suppression of disturbance. Cornus florida declined more sharply where A. saccharum increased. From 1983 to 1999, C. florida were less likely to survive if they were within 5 m of a A. saccharum. Light measurements showed that A. saccharum abundance correlated negatively with light available to C. florida, suggesting that increased shading by A. saccharum contributed to C. florida decline. The fungus, Discula destructiva causes the disease dogwood anthracnose that is associated with widespread decline of C. florida in the eastern United States. Tests for this pathogen in our study area were mostly negative. Other tests revealed that Armillaria root rot infected most C. florida, but this disease seemed to be a secondary effect of shading by A. saccharum. These results suggest that the lack of fire and other anthropogenic disturbances has resulted in an accelerated shift in dominance from Quercus and Carya to A. saccharum in the main canopy, and this shift, in turn, has resulted in increased shading of C. florida and its decline in previously more open Midwestern forests.     

Disinfection of some pathogens of mushroom cultivation by photocatalytic treatment

Photocatalytic disinfection of six bacteria and fungi, including pathogens of four mushroom diseases, Trichoderma harzianum, Cladobotryum varium, Spicellum roseum, and Pseudomonas tolaasii, and Escherichia coli and Bacillus subtilis, was studied. The photocatalyst reduced the number of viable microorganisms sufficiently by near-UV irradiation. Efficiency of disinfection was increased for P. tolaasii and E. coli, but not for T. harzianum, when the superhydrophilic properties of the photocatalyst were induced by 16h irradiation of the photocatalyst by near-UV light just before treatment of microorganisms. Efficiency of disinfection was also affected by the state of the microorganisms, temperature, and the thickness of suspensions of organisms. Tests of disinfecting ability of the photocatalyst in mushroom growing rooms indicate that it can be used effectively for reducing numbers of environmental bacteria and fungi under black light, and that it was also effective under white light.