Fungal Mats Research Articles

Arsenic removal from groundwater by pretreated waste tea fungal biomass

Arsenic contamination in ground water poses a serious threat on human health. The tea fungus, a waste produced during black tea fermentation has been examined for its capacity to sequester the metal ions from ground water samples. Autoclaved tea fungal mat and autoclaving followed by FeCl 3 pretreated tea fungal mat were exploited for removal of As(III), As(V) and Fe(II) from ground water sample collected from Kolkata, West Bengal, India. The biosorption rate tends to increase with the increase in contact time and adsorbent dosage. FeCl 3 pretreated and autoclaved fungal mats removed 100% of As(III) and Fe(II) after 30 min contact time and 77% of As(V) after 90 min contact time. The optimum adsorbent dosage was 1.0 g/50 mL of water sample. The results revealed that the FeCl 3 pretreated fungal mat could be used as an effective biosorbent for As(III) and As(V); autoclaved fungal mat for Fe(II) removal from ground water sample.

Supplementation of waste tea fungal biomass as a dietary ingredient for broiler chicks

The waste tea fungal biomass produced during black tea fermentation was investigated as a dietary ingredient in poultry feeds. A small portion of fungal mat was used as starter culture for the next cycle while the major portion is discarded as waste. Hence a trial study was carried out to utilize the waste fungal biomass as a supplementary diet for broiler chicks. The fungal biomass contained 179.38 g of crude protein, 120 g crude fibre, 4.82 g phosphorus, 6.56 g of calcium and 8.92 MJ metabolizable energy per kilogram of biomass. The dried tea fungus showed phytase activity of 23 IU/mg protein. The supplementation of tea fungal inclusion (TFI) at 150 g/kg concentration in poultry feed increased the feed consumption, body weight, performance efficiency factor (PEF) and the carcass characters of test broilers significantly ( P = 0.01) over the control. The histopathological examination of liver showed no abnormalities and the mortality rate was zero.

Effect of low oxygen concentrations on growth and α-amylase production of Aspergillus oryzae in model solid-state fermentation systems

Oxygen transfer in the fungal mat is a major concern in solid-state fermentation (SSF). Oxygen supply into the mycelial layers is hampered by diffusion limitation. For aerobic fungi, like Aspergillus oryzae, this oxygen depletion can be a severely limiting factor for growth and metabolite production. This paper describes the effects of a low oxygen concentration on growth at the levels of individual hyphae, colonies and overcultures, and on α-amylase production in overcultures. PDA medium was used to study the effect of a low oxygen concentration on hyphal elongation rate and branching frequency of hyphae, and radial extension rate of colonies of A. oryzae. We found similar saturation constants ( K O 2 ) of 0.1% (v/v in the gas phase) for oxygen concentration described with Monod kinetics, for branching frequency of hyphae and colony extension rate. When A. oryzae was grown as an over-culture on wheat-flour model substrate at 0.25% (v/v) oxygen concentration, the reduction in growth was more pronounced than as individual hyphae and a colony on PDA medium. Experimental results also showed that the specific α-amylase production rate under the condition of 0.25% (v/v) oxygen was reduced. Because the value of K O 2 is relatively low, it is reasonable to simplify the kinetics of growth of A. oryzae to zero-order kinetics in coupled diffusion/reaction models.

Factors influencing water solubility and plant availability of mineral compounds in the tripartite fairy rings ofMarasmius oreades(Bolt.: Fr.) Fr.

Fairy rings of M. oreades on pasture land were denoted by the dark-green vegetation. Grasses and rooted soils were analyzed to determine the influence of nonsymbiotic fungal mats on plant uptake of (heavy) metals. In soil colonized by M. oreades, degradation of 20-35% of plant roots in the presence of fungal laccase increased the content of dissolved organic carbon (3.74x), hexose sugar (3.75x), NH(3)/NH(4) (+) (5.1x), NO(3) (-) (11.1x), the number of aerobic bacteria (14.4x), and the formation of the phytochelators, oxalic, citric, and malonic acids. Soil pH diminished by 1.5 units mainly due to nitrification and carboxylic acid production. Although the solubility of trace elements increased (6.1x), plant roots had the same trace metal content as control plants, whereas the shoot content in Al, Cr, Fe, Ni, and Ti decreased by more than 50% due to inhibited root-to-shoot transfer. It is concluded that M. oreades and its associated bacteria increase the solubility of soil minerals significantly, but make them, due to presumed particularities in their complexation, less plant available and less re-complexable for the translocation into the plant vascular system.

Biochemical Engineering of Solid‐State Fermentation

AbstractFor Abstract see ChemInform Abstract in Full Text.

Surface ultrastructural studies on the germination, penetration and conidial development of Aspergillus flavus Link:Fries infecting silkworm, Bombyx mori Linn.

Aspergillosis is a common disease of the silkworm Bombyx mori Linn., caused by an insect mycopathogen Aspergillus flavus Link:Fries. The present study reveals the germination, penetration and conidial development of A. flavus on the larval integument of B. mori under SEM. Four different strains (NB18, KA, NB4D2 and NB7) of B. mori was surface inoculated with ca. of 1 x 10(6) conidia/ml. Each conidium germinated on the cuticle approximately 6 h after inoculation, forming a humpy or suctorial appressoria within 24 h. The hyphae which entered into haemocoel 2 day post-inoculation, grew and multiplied extensively, forming a mycelial complex, causing death of the host larva in about 4-5 days. This occurred with minimal breakdown of the internal tissues. Death of the host was followed by ramification of the fungus through the mesodermal and epidermal tissues, leading to larval mummification about 5-6 days after inoculation. Extensive fungal growths on the entire larval body followed, consisting of aerial hyphae, which developed branched conidiophores. The aerial hyphae with abundant conidiophores formed a confluent yellowish green fungal mat over the entire larval body in 6-7 days of post-inoculation. The tip of each emerging conidiophores gradually dilated and developed to become a bulbous head known as the vesicle. A large number of conidiogenous cells were produced over the entire surface of vesicle, which later developed into finger-like projections termed as sterigmata or phialides. The phialides matured within 2 days after the aerial hyphae emerged as evidenced by chains of conidia at their tips. The conidia were globose with externally roughened walls. The life cycle of the fungus on B. mori was completed in six to seven days.

Sclerotium rolfsii에 의한 가지 흰비단병

가지 흰비단병이 2002년 경상남도농업기술원 가지 재배포장에서 관찰되었다. 이 병의 병징은 가지의 지제부위가 수침상으로 변하며 썩으면서 병반부위가 암갈색으로 변하고 시들어 말라 죽는다. 병반부위에 흰색 곰팡이가 솜털처럼 발생하는 흰비단병 특유의 병징이 나타났다. 병반부와 PDA 배지에서 갈색을 띤 구형의 균핵이 많이 형성되었으며, 크기는 <TEX>$1.0{\sim}3.4mm$</TEX>였다. PDA배지 상에서 균사 생육적온은 <TEX>$30^{\circ}C$</TEX>이며, 병원균 특유의 clamp connection이 관찰되었으며 크기는 <TEX>$3.8{\sim}10.6{\mu}m$</TEX>였다. 병원균의 균학적 특성과 병원성을 검정한 결과 이 병을 Sclerotium rolfsii에 의한 가지 흰비단병으로 명명할 것을 제안한다. A stem rot of eggplant (Solanum melongena) was found in experimental field of Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted and white turf of fungal mycelium mats was spread over lesions. Sclerotia were farmed on the stems near soil line. The sclerotia of the fungus eadily were produced in artificial media such as PDA at <TEX>$30^{\circ}C$</TEX>. The sclerotia were globoid, <TEX>$1.0{\sim}3.4mm$</TEX> in diameter and brown in color. The optimum temperature for growth of the fungus was about <TEX>$30^{\circ}C$</TEX>. The typical clamp connections were found in the hypha formed on PDA, and was <TEX>$3.8{\sim}10.6{\mu}m$</TEX> in size. On the basis of mycological characteristics and pathogenecity test, the fungus was identified as Sclerotium rolfsii. This is the first report of stem rot of eggplant caused by Sclerotium rolfsii in Korea.

Phytase and phosphatase producing fungi in arid and semi-arid soils and their efficiency in hydrolyzing different organic P compounds

Seven most efficient phytase and phosphatases producing fungi were isolated from the soils of arid and semi-arid regions of India and tested for their efficiency on hydrolysis of two important organic P compounds: phytin and glycerophosphate. The native soil organic P may be exploited after using these organisms as seed inoculants, to help attain higher P nutrition of plants. The identified organisms belong to the three genera: Aspergillus, Emmericella and Penicillium. Penicillium rubrum released the most acid into the medium during growth. Aspergillus niger isolates were found to accumulate biomass the fastest. A significant negative correlation ( r=−0.593, n=21, p<0.01) was observed between the development of fungal mat and pH of the media. The extracellular (E) phosphatases released by different fungi were less than their intracellular (I) counterpart, but the trend was reversed in case of phytase production. The E:I ratio of different fungi ranged from 0.39 to 0.86 for acid phosphatase, 0.29 to 0.41 for alkaline phosphatases and 9.4 to 19.9 for phytase. The efficiency of hydrolysis of different organic P compounds of different fungi varied from 2.12–4.85 μg min −1 g −1 for glycerophosphate to 0.92–2.10 μg min −1 g −1 for phytin. The trend of efficiency was as follows: Aspergillus sp.> Emmericella sp.> Penicillium sp. The results indicated that the identified fungi have enough potential to exploit native organic phosphorus to benefit plant nutrition.

Serum-specific antibodies in rabbits naturally infected with Trichophyton mentagrophytes.

In the present study, we investigated the humoral immune response of rabbits to Trichophyton mentagrophytes (sensu lato) proteins obtained from keratin-rich media in vitro. The test rabbits were naturally infected with T. mentagrophytes. The production of keratinolytic enzymes in T. mentagrophytes was stimulated by growing cultures with keratin as a sole nitrogen source. The proteins were isolated from a protein extract prepared from the fungal mat. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed three bands. Bands with Mr 20 and 30 kDa were glycosylated, whereas a band of 18 kDa was not. The rabbits' humoral immune responses to the total protein extract of T. mentagrophytes and to the proteins with keratinolytic activity was studied by immunoblotting. IgG from infected rabbits' sera revealed eight dominant bands with apparent molecular weights between 20 and 75 kDa. Bands of 20, 30 and 33 kDa appeared with a frequency rate of 76% only on immunoblots of infected rabbit serum. Using an indirect enzyme-linked immunosorbent assay (ELISA), we observed a significant increase in specific antibodies in a group of infected rabbits compared to a control group (P < 0.001). The ELISA exhibited 95% sensitivity and 83% specificity at the optimal cut-off value, with 90% predictive values of a positive and a negative result. Under these conditions, it could be used in the accurate detection of specific antibodies in sera of infected rabbits.

Penicillium oxalicum에 의한 멜론 푸른곰팡이병

2002년 4월 경남 함안군 대산면 농가에서 비닐터널 재배중인 멜론(품종, 가야백자)의 과일비대기부터 성숙기까지 과일에서 푸른곰팡이병이 발생하였다. 병징은 멜론과 일의 꽃자리부분이 약간 함몰되고 부패되어 그 위에 푸른곰팡이가 많이 형성하였다. 분리한 병원균의 균사는 처음 흰색에서 푸른색을 띄며, 분생포자를 아주 많이 형성하였다. 분생포자의 모양은 타원형이고 푸른색으로 크기가 2.6~7.4<TEX>$\times$</TEX>2.6~5.8 <TEX>$\mu\textrm{m}$</TEX>이었다. 분생포자병은 균사표면으로부터 형성되고, Stipes의 크기가 86~320<TEX>$\times$</TEX>2.8~4.3 <TEX>$\mu\textrm{m}$</TEX>로 가늘고 길며, Matulae의 크기는 12.4~31.6<TEX>$\times$</TEX>2.6~4.2 <TEX>$\mu\textrm{m}$</TEX> 이고, Phialide는 침상이고 크기가 8.2~15.4<TEX>$\times$</TEX>3.6~4.6 <TEX>$\mu\textrm{m}$</TEX>이었다. 균사생육 적온은 3<TEX>$0^{\circ}C$</TEX>였다. 포장에서 이병과율은 4.3% 이었으며 고온다습 조건에서 발병이 잘되었다. 분리된 병원균을 건전한 멜론에 접종한 결과 병원성을 확인하였고 병징도 똑같았다 이상과 같이 이 병원균을 Peniciliium oxalicum에 의한 멜론 푸른곰팡이병으로 명명할 것을 제안한다. In April of 2002, fruit rot infected with blue mold was found at maturing stage of melon (Cucumis melo cv. Gayabaegja) growing under tunnel cultivation in Daesan-myon, Haman-gun, Gyeongnam Province, Korea. Floral parts were infected first and colonized by fungal mycelial mats. From the point of infection, fruits become collapsed and mostly ruptured. The pathogenic fungus from infected fruits was isolated. Colony color of the fungus was white on MEA and CYA agar, Conidia were ellipsoid and 2.6~7.4<TEX>$\times$</TEX>2.6~5.8 <TEX>${\mu}{\textrm}{m}$</TEX> in size. Stipes were 86~320<TEX>$\times$</TEX>2.8~4.3 <TEX>${\mu}{\textrm}{m}$</TEX> in size. Metulae were 12.4~31.6<TEX>$\times$</TEX>2.6~4.2 <TEX>${\mu}{\textrm}{m}$</TEX> in size. Phialides were ampulliform to cylindroid, and 8.2~15.4<TEX>$\times$</TEX>3.6~4.6 <TEX>${\mu}{\textrm}{m}$</TEX> in size. Rate of infected fruits in the field was 4.3%. Based on the cultural and mycological characteristics and pathogenecity test on host plants, the fungus was identified as Penicillium oxalicum, This is the first report on the blue mold of melon (Cucumis melo) caused by P. oxalicum in Korea.

Water and glucose gradients in the substrate measured with NMR imaging during solid-state fermentation with Aspergillus oryzae.

Gradients inside substrate particles cannot be prevented in solid-state fermentation. These gradients can have a strong effect on the physiology of the microorganisms but have hitherto received little attention in experimental studies. We report gradients in moisture and glucose content during cultivation of Aspergillus oryzae on membrane-covered wheat-dough slices that were calculated from (1)H-NMR images. We found that moisture gradients in the solid substrate remain small when evaporation is minimized. This is corroborated by predictions of a diffusion model. In contrast, strong glucose gradients developed. Glucose concentrations just below the fungal mat remained low due to high glucose uptake rates, but deeper in the matrix glucose accumulated to very high levels. Integration of the glucose profile gave an average concentration close to the measured average content. On the basis of published data, we expect that the glucose levels in the matrix cause a strong decrease in water activity. The results demonstrate that NMR can play an important role in quantitative analysis of water and glucose gradients at the particle level during solid-state fermentation, which is needed to improve our understanding of the response of fungi to this nonconventional fermentation environment.

Fungi and their ability to decolourize azo and anthraquinonic dyes

One hundred and fifteen fungi from different physio-ecological groups were compared for their capacity to decolourize two structurally different dyes in agar plates. We found that the azo dye, Acid Red 183, was much more resistant to decolourization by the examined strains in both solid and liquid cultures. Among the tested fungi, 69 strains showed decolourization of the anthraquinonic dye, Basic Blue 22, within 5–14 days, and only 16 strains were able to decolourize the azo dye, Acid Red 183, within 21 days. Furthermore, the potential of selected strains for decolourization of dyes was examined with regard to their extracellular oxidative factors both enzymatic and non-enzymatic. In static aqueous culture, the three selected fungi (Bjerkandera fumosa, Kuehneromyces mutabilis, and Stropharia rugoso-annulata) formed fungal mats, which did not decolourize any dye beyond some mycelial sorption. In comparison to the static cultures, the agitated cultures (180 rpm) removed 75 to 100% of the colour of Basic Blue 22 and 20 to 100% of Acid Red 183 colour.

Intra-particle oxygen diffusion limitation in solid-state fermentation.

Oxygen limitation in solid-state fermentation (SSF) has been the topic of modeling studies, but thus far, there has been no experimental elucidation on oxygen-transfer limitation at the particle level. Therefore, intra-particle oxygen transfer was experimentally studied in cultures of Rhizopus oligosporus grown on the surface of solid, nutritionally defined, glucose and starch media. The fungal mat consisted of two layers--an upper layer with sparse aerial hyphae and gas-filled interstitial pores, and a dense bottom layer with liquid-filled pores. During the course of cultivation ethanol was detected in the medium indicating that oxygen was depleted in part of the fungal mat. Direct measurement of the oxygen concentrations in the fungal mat during cultivation, using oxygen microelectrodes, showed no oxygen depletion in the upper aerial layer, but revealed development of steep oxygen concentration gradients in the wet bottom layer. Initially, the fungal mat was fully oxygenated, but after 36.5 hours oxygen was undetectable at 100 microm below the gas-liquid interface. This was consistent with the calculated oxygen penetration depth using a reaction-diffusion model. Comparison of the overall oxygen consumption rate from the gas phase to the oxygen flux at the gas-liquid interface showed that oxygen consumption of the microorganisms occurred mainly in the wet part of the fungal mat. The contribution of the aerial hyphae to overall oxygen consumption was negligible. It can be concluded that optimal oxygen transfer in SSF depends on the available interfacial gas-liquid surface area and the thickness of the wet fungal layer. It is suggested that the moisture content of the matrix affects both parameters and, therefore, plays an important role in optimizing oxygen transfer in SSF cultures.

Molecular evolution of Sry and Sox gene

The mammalian Sry on the short arm of the Y chromosome encodes a nuclear factor-like protein harboring a DNA-binding domain known as the HMG box. The Sox genes encode similar factor like proteins, but the sequence similarity of the HMG box to that of Sry is variable as being at least 60%. The functional relationship of Sox to Sry genes with special reference to sex determination is unclear except for a few items such as human autosomal Sox9. Thus, it is significant to know more about the evolutionary in addition to the functional relationship between Sry and Sox genes for deepening and broadening our understanding concerning primary sex determination. Therefore, to clarify the ancestry and molecular evolution of the mammalian sex determining gene Sry with its evolutionary relationships to the Sox gene, a molecular phylogenetic tree for the HMG box superfamily was constructed and analyzed, and the following conclusions were reached: (1) The nuclear non histone HMG proteins are supposedly the oldest, appearing at least more than one billion years ago, before the divergence of animals and plants. They diverged into two subgroups: one contains HMG14 and HMG17, and the other one contains HMG1 and HMG2 with various other genes. Subsequent divergences include the nucleolar UBF, nuclear SSRP as well as fungal mating protein Mc, MAT and Ste11. (2) The Sox and Sry genes diverged following the diversification of lymphoid transcription factors TCF and LEF. The Sry gene might have definitely evolved from the Sox gene cluster a few hundred million years ago. Additionally, the marsupial Sry, e.g. from Wallabie's and Dunnart's, is distinguished by being distant from eutherian Sry, but being closely related to the Sox gene cluster. (3) Molecular evolutionary rates estimated in mammalian Sry as the divergent rate per 100 million years are much higher than in Sox genes or other genes from the HMG box superfamily. This rapid evolution of Sry might agree with the fact that the Srys are present not on the pseudoautosomal region but on the distal region with no recombination of the Y chromosomal short arm.

Iron bacterial and fungal mats, Bajocian stratotype (Mid-Jurassic, northern Normandy, France)

The Oolithe ferrugineuse de Bayeux Formation is located at the historical Bajocian stratotype of Sainte-Honorine-des-Pertes, north of Bayeux, Normandy. The condensed formation ranges from the base of the Humphriesianum Zone to the Parkinsoni Zone and is divided into four beds of decimetric scale. Three main microfacies are present: (1) oncoid rudstones, (2) ooid bioclastic packstones and (3) silty burrowed wackestones/packstones. Sedimentation took place in a very quiet environment, below the photic zone and below or near the storm wave base. The general setting is a distal carbonate ramp, its lower part characterized by hemipelagic sedimentation indicated by the presence of planktonic foraminifers. The inferred depth is around 100 m. Free oxygen concentration was low. Dysaerobic conditions are indicated by a scarcity of benthic macrofauna. Ferruginous structures are numerous in the first two microfacies, and absent in the last. Hematite staining is not uniform and follows many sedimentary patterns. Among the more widespread Fe structures are perforation infillings with endolithic micro-organisms, microstromatolites, oncoids, ooids, blisters, coatings and hardgrounds. These structures can be associated and none are mutually exclusive. Hematite-coated filaments of different sizes and shapes are observed in the micrite matrix: the walls of various organisms; the calcite crystals associated with the Fe cortical laminations; the perforations and burrow; the hardgrounds; and microstromatolites. Petrographical and SEM examinations suggest that the laminated crusts (oncoids and hardgrounds) are formed by microbial iron mats dominated by filamentous bacteria and fungi. Seven types of microbes are recognized: filaments (five morphotypes), spheroidal bodies and stalked bodies. Filamentous microfossils of type 1 to 4 resemble the present-day filamentous bacteria (Beggiatoales and Cytophagaceae). Because of their large diameter and their branching nature, filaments of type 5 are possibly filamentous fungi. Another argument in favor of fungi is the presence of stalked and spheroidal bodies that resemble zoosporangia and oogonia of some Oomycota. In deep, calm and dysaerobic waters, many interfaces (e.g. between aerobic and dysaerobic waters) are present in the sediments. The stability of the soluble reduced state of iron (Fe2+) is higher at such interfaces, and many ferric iron-encrusted microbial fossils are observed. Iron could thus serve as an electron donor for microbial iron-oxidation processes. Other microbial iron deposition pathways are also possible. It appears that, regardless of geological age (Paleozoic, Mesozoic) and geographical location, the same microbiological mechanisms are probably responsible for the red color in calcareous stratified or unstratified bodies. The presence of fossilized iron-encrusted bacteria and fungi at interfaces may therefore serve as an indicator of anoxic to dysaerobic conditions in various paleo(micro)environments.

The Time–Dose–Mortality Modeling and Virulence Indices for Two Entomophthoralean Species, Pandora delphacis and P. neoaphidis, against the Green Peach Aphid, Myzus persicae

Bioassays of two entomophthoralean fungi, Pandora delphacis and P. neoaphidis, were conducted on the green peach aphid, Myzus persicae. For inoculation, batches of ≤3-day-old nymphs on detached cabbage leaves were exposed to conidial showers of varying time lengths from sporulating fungal mats produced in liquid culture. Eight dosages of each pathogen were used to inoculate 88–345 nymphs each. The nymphs inoculated were maintained at 18–20°C and L:D (12:12) at high humidity and were examined daily for mortality. The resulting data were analyzed using a time–dose–mortality modeling technique, yielding the parameters for time and dose effects of the two fungal species. P. delphacis killed the aphid more rapidly than P. neoaphidis, though both had similar slopes for dose effect. The values of LD50 estimated on days 3–7 after exposure decreased from 18.1 to 0.9 conidia/mm2 for P. delphacis and from 17.0 to 0.04 conidia/mm2 for P. neoaphidis. The estimates of LT50 for the two pathogens were similar at dosages of more than 5 conidia/mm2 but differed at lower dosages. Based on the time–dose–mortality relationships fitted and the virulence indices estimated, P. delphacis is a promising microbial agent for aphid control and is competitive with P. neoaphidis.

Microbial mats associated with bryozoans (Coorong Lagoon, South Australia)

Bryostromatolites are laminated carbonate rocks composed of bryozoan zoarial laminae. The laminated texture is frequently caused by patterns of bryozoan self overgrowth as a regular defensive tactic against microbial fouling. In the Coorong Lagoon (South Australia), another type of bryostromatolite is present where the laminated growth of the weakly calcifying bryozoan speciesConopeum aciculata is postmortally stabilized by cyanobacterial mats at the surface, and fungal mats settling in the zooecial cavities.

Allergens of Curvularia lunata during cultivation in different media

Background: Despite enormous efforts toward the standardization of fungal extracts, only a few extracts have been characterized that are relevant for the diagnosis and immunotherapy of allergy-associated disorders. Objective: The goal of this study was to determine the optimum growth condition of Curvularia lunata , an important fungal allergen for quality raw material, and to analyze the C lunata extract for IgE- and IgG–binding proteins. Methods: C lunata was grown in synthetic (Czapeck Dox medium), semisynthetic (Sabouraud’s broth [SB]), and natural media (potato dextrose [PD]) for different periods of time. The extracts were probed for allergenic and antigenic activity, with pooled patient sera and polyclonal antibodies raised against C lunata by means of ELISAs, immunoblots (in vitro), and intradermal tests (in vivo). Results: The growth of C lunata was better in semisynthetic media (ie, SB) compared with other types of media. Dry weight and protein content was maximum in the 7-day culture of SB. ELISA with pooled sera from C lunata –sensitive patients exhibited that cultures grown in SB for 11 to 13 days and PD plus 1.0% agar for 5 days were the most potent. Intradermal tests with 11- to 13-day SB culture extract showed maximum skin reactivity in allergy patients. Immunoblots with patient sera showed 10 to 14 IgE-binding proteins in 5- to 15-day SB cultures. Analysis of 5- to 15-day SB extract with rabbit sera showed 10 to 16 IgG-binding proteins. Conclusions: The extract from 11- to 13-day SB cultures were most biologically potent (intradermal tests) and showed high antigenic and allergenic reactivity (ELISA and immunoblot). The addition of yeast extract did not affect the dry weight and protein content of the C lunata extract. Furthermore, addition of agar in PD medium increases the dry weight and protein content of the fungal mat. Synthetic media was not suitable for mass cultivation of C lunata . (J Allergy Clin Immunol 1999;104:857-62.)

Comparative studies on the biochemistry of Penicillium albicans (alkalosensitive) and Vertiallium lateritium, (facultative alkalophile) with special reference to the role of sodium ion in alkalophily

High alkalinity inhibited sugar utilization by the alkalosensitive fungus ( P. albicans) and increased the polysaccharide content in its fungal mats. The total amino-N content decreased in the culture of P. albicans, whereas its quantity increased in the biomass with progressive alkalinity. Alkalinity inhibited nitrogen uptake and protein synthesis leading to a corresponding decline in growth, and hence apparent alkalosensitivity. High alkalinity caused enhancement of sugar uptake by the facultative alkalphile V. lateritium associated with higher reducing sugar contents and decreased polysaccharide accumulation in mycelial mats. The amino-N content increased in the culture medium of V. lateritium and decreased in the biomass with pH increase. The utilization of soluble nitrogen increased, accompanied by increased protein synthesis, leading to maximum growth at higher pHs, and hence apparent alkalophilicity. The sodium content in the medium of the alkalosensitive fungus decreased at high pHs associated with a respective increase in the biomass. In contrast, in the alkalophilic fungus, the sodium content increased in the culture and decreased in the biomass with increased alkalinity, indicating an important role played by this ion. No clear relationship could be obtained between phosphorus content in cultures or biomass of the two tested fungi and alkalophilicity.

Germination, penetration, and invasion of Beauveria bassiana on silkworm, Bombyx mori, causing white muscardine

White muscardine is a common disease of the silkworm Bombyx mori caused by an insect mycopathogen Beauveria bassiana. The present study revealed the germination, penetration, and invasion of B. bassiana on the larval integument of B. mori. The NB18 strain of B. mori was surface inoculated with concentrations of 1×106 conidia/ml. Each conidium, germinated approximately 8 h after inoculation, forming an appressorium within 24 h and the hypha entered the cuticle by forming a clear circular hole. The hyphae reached the haemocoel, where they grew and multiplied extensively, forming a mycelial complex, causing death of the host larva in about five‐six days. This occurred with minimal breakdown of the internal tissues. Death of the host was followed by ramification of the fungus through the mesodermal and epidermal tissues, leading to larval mummification about six days post‐inoculation. Extensive fungal outgrowths followed, mostly through the intersegmental regions of the larva, and formed aerial hyphae, which gave rise to branched conidiophores forming a confluent white fungal mat over the entire larval body in six‐seven days. The life‐cycle of the fungus on B. mori was completed in seven‐eight days.