The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.

Zygomycetes in Human Disease

Billions of tons of desert dust move through the atmosphere each year. The primary source regions, which include the Sahara and Sahel regions of North Africa and the Gobi and Takla Makan regions of Asia, are capable of dispersing significant quantities of desert dust across the traditionally viewed oceanic barriers. While a considerable amount of research by scientists has addressed atmospheric pathways and aerosol chemistry, very few studies to determine the numbers and types of microorganisms transported within these desert dust clouds and the roles that they may play in human health have been conducted. This review is a summary of the current state of knowledge of desert dust microbiology and the health impact that desert dust and its microbial constituents may have in downwind environments both close to and far from their sources.

Atmospheric Movement of Microorganisms in Clouds of Desert Dust and Implications for Human Health

Microbiological deterioration and degradation of synthetic polymeric materials: recent research advances

Aflatoxin in food and feed: occurrence, legislation and inactivation by physical methods

Moulds in food spoilage

Nine isolates of Trichoderma were collected from Assiut Governorate,Egypt, as leaf surface and endophytic fungi associated with onion ﬂorastalks. Four isolates were identiﬁed as Trichoderma harzianum, while ﬁveisolates were belonging to Trichoderma longibrachiatum. The antagonisticactivity of these isolates against onion purple blotch pathogen Alternariaporri was studied in vitro using dual culture assay. All tested Trichodermaisolates showed mycoparasitic activity and competitive capability againstthe mycelial growth of A. porri. Mycoparastic activity of Trichoderma wasmanifested morphologically by the overgrowth upon the mycelial growthof the pathogen and microscopically by production of coiling hyphaearound pathogen hyphae. Isolates of T. harzianum exhibited high abilityto compete on potato dextrose agar (PDA) medium causing the maximumrate of pathogen inhibition (73.12%), while isolates of T. longibrachiatumshowed inhibition rate equalling 70.3%. Chitinase activity of Trichodermawas assayed, and T. harzianum Th-3013 showed the maximum value con-tributing 2.69 U/min. Application of T. harzianum Th-3013 to control pur-ple blotch disease in vivo under greenhouse conditions caused diseasereduction up to 52.3 and 79.9% before and after 48 h of pathogen inocu-lation, respectively, while the fungicide Ridomil Gold Plus caused diseasereduction comprising 56.5 and 71.7%, respectively. This study proved thatT. harzianum Th-3013 as a biocontrol agent showed signiﬁcant reductionin onion purple blotch disease compared with the tested fungicide.IntroductionPurple blotch disease, caused by Alternaria porri (Ellis)Cif., is one of the most serious diseases that wide-spread in many parts of the world, restricted to Alliumspp. and more prevalent in warm and humid environ-ments (Cramer 2000; Suheri and Price 2000). Purpleblotch disease caused signiﬁcant reduction in bulband seed yield of the onion crop (Gupta and Pathak1988). The disease is more severe on seed crop ascompared to bulb crop causing sometimes 100% loos-ing of the seed production (Singh et al. 1992;Schwartz 2004). Although chemical control of onionblotch had been practised and its success depends lar-gely on high frequency of spraying, but today, thereare strict regulations on chemical fungicide use due tocarcinogenic effects, residual toxicity problems, envi-ronmental pollution and development of fungicide-resistant strains (Benitez et al. 2004; Rial-Otero et al.2005). Therefore, there are a large number of studiesthat have been devoted to apply a biological control asnature-friendly alternative method (Siameto et al.2010; Soria et al. 2012). The potential of Trichodermaspecies as biocontrol agents of plant diseases was ﬁrstrecognized in the early 1930s (Weindling 1932), andsince then, there have been extensive efforts in thecommercial production of them for disease control ina number of crops (Harman 1996; Gardener and Frav-el 2002). Recently, several investigation proved thatTrichoderma have been used to control many foliar

Isolation of Trichoderma and Evaluation of their Antagonistic Potential against Alternaria porri

In wheat, corn and sorghum grains twenty-six genera and seventy-seven species including sixteen ofAspergillus and twenty-one ofPenicillium were identified. In grain samples adjusted to various moisture levels (up to 18.8 % on a dry-weight basis) and stored for 4 months at 8†, 20† and 30† C seed-borne fungi were monthly identified and counted, and the germinability of the grains was tested. In the control samples (moisture content 7.1–8.2 %) temperature had no effect on the fungal counts and on the precentage germination. With the rise of temperature and moisture content the fungal counts markedly increased and the germinability declined. The list of fungi dominant in one or more of the experiments, included eight species ofAspergillus, six ofPenicillium, two ofFusarium and one each ofAlternaria andCurvularia. The order of dominance of these fungi varied according to the type of grain, the length of storage and the treatment.A. niger was the dominant organism in the control samples of the three grains. It could grow successfully at high moisture contents but above 15 %, it was usually overgrown by other fungi. In wheatP. citrinum andA. sydowii, in cornP. citrinum andA. terreus, and in sorghumA. terreus andA. niger were the dominant fungi at moisture contents above 15 % after four months storage at 30† C. When stored at 8† CPenicillium species tended to predominate over other fungi in grains with high moisture contents. In surface-sterilized grains adjusted to 15 % moisture content, inoculated with six dominant fungi separately and incubated at 30† C,A. niger, P. citrinum andP. variabile caused severe deterioration in the three grains;A. ochraceus in wheat only andF. moniliforme in wheat and corn;C. spicifer was slightly injurious to the three grains.

Studies on the fungus flora of three grains in Egypt.

Thirty-four genera and 80 species in addition to one variety of A. nidulans were identified from 40 soil samples colleted from different places in desert of Saudi Arabia. More than forty-two species are new records from Saudi Arabian soils. Aspergillus and Penicillium contributed the greatest number of species (15 species + 1 variety and 13 species respectively).

Survey of the mycoflora of desert soils in Saudi Arabia

Twenty-five genera and sixty-eight species, in addition to one variety of each of A. chevalieri, A. flavus and A. nidulans were isolated from 40 soil samples collected from desert in Saudi Arabia on 5% sodium chloride-Czapek's agar. The most frequent genera were Aspergillus (20 species + 3 varieties), Penicillium (14 species), Drechslera (2 species) and Ulocladium (3 species), followed by Stemphylium (1 species), Scopulariopsis (2 species), Trichoderma (1 species) Botryotrichum (2 species), Cladosporium (3 species), Myrothecium (1 species) and Alternaria (1 species). From these genra A. amstelodami, A. chevalieri, A. ruber, A. ochraceus, P. brevi-compactum, P. ?cyano-fulvum, P. notatum, D. spicifera, U. consortiale, S. botryosum, S. brevicaulis, T. viride, B. piluliferum, C. herbarum, M. verrucaria and A. alterata were the most common. The results obtained in this investigation reveal that the fungus flora of Saudi Arabian soils is of halophilic nature.

Osmophilic fungi of desert soils in Saudi Arabia

Mycogenic synthesis of silver nanoparticles (AgNPs) was carried out in the present investigation using an aqueous extract of endophytic non-pathogenic Alternaria solani F10 (KT721914). The mycosynthesized AgNPs were characterized by means of spectroscopic and microscopic techniques. The surface plasmon resonance found at 430 nm confirmed the formation of stable AgNPs for several weeks at room temperature. Also, the results revealed the formation of spherical and monodispersed AgNPs with an average size of 14.8 ± 1.2 nm. The FT-IR spectrum suggested that the fungal extracellular proteins and secondary metabolites had the role in Ag reduction and AgNPs capping of which protein Ag nanoconjugates were formed. Furthermore, the mycosynthesized AgNPs exhibited potent antifungal activity against different pathogenic isolates of the same Alternaria solani fungus, the causal pathogen of tomato early blight disease. The antifungal efficiency of the AgNPs at 1, 5 and 10 ppm were evaluated for 8 days after incubation by measuring the inhibition rate of fungal radial growth. The results were further supported by investigating fungal hyphae morphology alteration by scanning and transmission electron microscopy. Treated fungal hyphae showed formation of pits and pores. Also, the mycosynthesized AgNPs were able to pass and distribute throughout the fungal cell area and interact with the cell components.

/pdf/assessment-of-protein-silver-nanoparticles-toxicity-against-23x07hn8xr.pdf

Sobhy I. I. Abdel-Hafez

Papers

Isolation of Trichoderma and Evaluation of their Antagonistic Potential against Alternaria porri

Studies on the fungus flora of three grains in Egypt.

Survey of the mycoflora of desert soils in Saudi Arabia

Osmophilic fungi of desert soils in Saudi Arabia

Assessment of protein silver nanoparticles toxicity against pathogenic Alternaria solani.