Role of hydrophobic surface proteins in mediating adherence of group B streptococci to epithelial cells.

Determination of the cell-surface hydrophobicity of group B streptococci by hydrophobic interaction chromatography on phenyl-Sepharose revealed that human and bovine group B streptococcal isolates with protein surface antigens, either alone or in combination with polysaccharide antigens, were mainly hydrophobic, whereas those with polysaccharide antigens alone were mainly hydrophilic. Removal of capsular neuraminic acid enhanced, and pronase treatment reduced, surface hydrophobicity. The hydrophobic surface proteins, solubilized by mutanolysin treatment of the bacteria and isolated by hydrophobic interaction chromatography, appeared in SDS-PAGE as numerous protein bands. Staphylococcal carrier cells loaded with antibodies produced against hydrophobic surface proteins agglutinated specifically with hydrophobic group B streptococci. No agglutination reaction was observed with hydrophilic cultures. Hydrophobic group B streptococci adhered to buccal epithelial cells in significantly higher numbers than did hydrophilic cultures. The adherence of group B streptococci to epithelial cells was inhibited in the presence of isolated hydrophobic proteins and in the presence of specific antibodies produced against hydrophobic proteins. The results of this study demonstrate a close relation between the occurrence of type-specific antigens, surface hydrophobicity and the adherence of group B streptococci to epithelial cells.     

Reversion of autocrine transformation by a dominant negative platelet-derived growth factor mutant.

A non-receptor-binding mutant of the platelet-derived growth factor (PDGF) A chain, PDGF-0, was generated by exchanging 7 amino acids in the sequence. The mutant chains formed dimers that were similar to wild-type PDGF-AA with regard to stability and rate of processing to the mature 30-kDa secreted forms. Moreover, the mutant chains formed disulfide-bonded heterodimers with the PDGF B chain in NIH 3T3 cells heterodimer underwent the same processing and secretion as PDGF-AB. Transfection of c-sis-expressing 3T3 cells with PDGF-0 significantly inhibited the transformed phenotype of these cells, as determined by the following criteria. (i) Compared with PDGF-0-negative clones, PDGF-0-producing clones showed a reverted morphology. (ii) Clones producing PDGF-0 grew more slowly than PDGF-0-negative clones, with a fivefold difference in cell number after 14 days in culture. (iii) The expression of PDGF-0 completely inhibited the ability of the c-sis-expressing 3T3 cells to form colonies in soft agar; this inhibition was overcome by the addition of recombinant PDGF-BB to the culture medium, showing that the lack of colony formation of these cells was not due to a general unresponsiveness to PDGF. The specific expression of a PDGF-0/PDGF wild-type heterodimer in COS cells revealed that the affinity of the mutant heterodimer for the PDGF alpha receptor was decreased by approximately 50-fold compared with that of PDGF-AA. Thus, we show that a non-receptor-binding PDGF A-chain mutant neutralizes in a trans-dominant manner the autocrine transforming potential of the c-sis/PDGF B chain by forming low-affinity heterodimers with wild-type PDGF chains. This method of specifically antagonizing the effect of PDGF may be useful in investigations of the role of PDGF in normal and pathological conditions.     

Comparison of the adhesion properties of Deleya marina and the exopolysaccharide-defective mutant strain DMR.

Deleya marina 219 (ATCC 25374) produces large quantities of an acidic exopolysaccharide and characteristically forms mucoid colonies and large aggregates of cells. The exopolysaccharide of wild-type D. marina cells appears to occur as both film and fibrils in electron micrographs. The organization of exopolymeric material was indicative of structural heterogeneity. A spontaneous rough-colony mutant defective in exopolysaccharide, D. marina DMR, has been isolated. The absence of exopolymer corresponds to a nonmucoid, nonaggregating, adhesion-altered phenotype. In microplate adhesion assays, wild-type cells grown at 19 or 25 degrees C attached to hydrophilic surfaces but not to a hydrophobic surface. In contrast, mutant cells exhibited a significantly reduced level of attachment to hydrophilic surfaces and increased adhesion to a hydrophobic surface.     

Comparison of the adhesion properties of Deleya marina and the exopolysaccharide-defective mutant strain DMR.

Deleya marina 219 (ATCC 25374) produces large quantities of an acidic exopolysaccharide and characteristically forms mucoid colonies and large aggregates of cells. The exopolysaccharide of wild-type D. marina cells appears to occur as both film and fibrils in electron micrographs. The organization of exopolymeric material was indicative of structural heterogeneity. A spontaneous rough-colony mutant defective in exopolysaccharide, D. marina DMR, has been isolated. The absence of exopolymer corresponds to a nonmucoid, nonaggregating, adhesion-altered phenotype. In microplate adhesion assays, wild-type cells grown at 19 or 25 degrees C attached to hydrophilic surfaces but not to a hydrophobic surface. In contrast, mutant cells exhibited a significantly reduced level of attachment to hydrophilic surfaces and increased adhesion to a hydrophobic surface.     

Cooperation among germinating spores facilitates the growth of the fungus, Neurospora crassa

Fusions between individuals are a common feature of organisms with modular, indeterminate life forms, including plants, marine invertebrates and fungi. The consequences of fusion for an individual fungus are poorly understood. We used wild-type and fusion mutant strains of the genetic model Neurospora crassa to chronicle the fitness in two different laboratory habitats, and in each experiment started colonies from multiple different densities of asexual spores. On round Petri dishes, fusion enabled wild-type colonies to grow larger than mutant (soft) colonies; but in linear 'race tubes', the soft mutant always grew more quickly than the wild-type. Starting a colony with more spores always provided an advantage to a wild-type colony, but was more often neutral or a cost to the soft mutant. The ability to fuse does not provide a consistent advantage to wild-type colonies; net benefits are shaped by both habitat and initial spore densities.     

Evaluation of media for monitoring fecal streptococci in seawater.

The selectivity of KF streptococcus agar (KF) for monitoring fecal streptococci (FS) in seawater was examined in 234 samples of Mediterranean water and compared with the selectivity of M-Enterococcus agar (M-Ent) for 124 samples and with bile-esculin-azide agar (BEA) for 17 samples. KF was found to be unsuitable for marine water because Vibrio alginolyticus and other gram-negative bacilli indigenous to this environment grew well on it and produced red colonies identical to those of FS. In 26% of samples, some with high counts of red colonies on the membrane filters (MF), there were no streptococci, only gram-negative bacilli and staphylococci, and in an additional 23.1% the streptococci constituted less than 50% of the "typical" red colonies on the MF. V. alginolyticus also produced FS-like colonies on MF incubated on BEA but was not isolated from MF incubated on M-Ent. Although staphylococci grew and produced FS-like colonies on all three media, M-Ent was the most selective since no gram-negative bacilli were isolated from MF incubated on it.     

Evaluation of media for monitoring fecal streptococci in seawater

The selectivity of KF streptococcus agar (KF) for monitoring fecal streptococci (FS) in seawater was examined in 234 samples of Mediterranean water and compared with the selectivity of M-Enterococcus agar (M-Ent) for 124 samples and with bile-esculin-azide agar (BEA) for 17 samples. KF was found to be unsuitable for marine water because Vibrio alginolyticus and other gram-negative bacilli indigenous to this environment grew well on it and produced red colonies identical to those of FS. In 26% of samples, some with high counts of red colonies on the membrane filters (MF), there were no streptococci, only gram-negative bacilli and staphylococci, and in an additional 23.1% the streptococci constituted less than 50% of the "typical" red colonies on the MF. V. alginolyticus also produced FS-like colonies on MF incubated on BEA but was not isolated from MF incubated on M-Ent. Although staphylococci grew and produced FS-like colonies on all three media, M-Ent was the most selective since no gram-negative bacilli were isolated from MF incubated on it.     

Regulation of fatty acid metabolism by FadR is essential for Vibrio vulnificus to cause infection of mice

The opportunistic bacterial pathogen Vibrio vulnificus causes severe wound infection and fatal septicemia. We used alkaline phosphatase insertion mutagenesis in a clinical isolate of V. vulnificus to find genes necessary for virulence, and we identified fadR, which encodes a regulator of fatty acid metabolism. The fadR::mini-Tn5Km2phoA mutant was highly attenuated in a subcutaneously inoculated iron dextran-treated mouse model of V. vulnificus disease, was hypersensitive to the fatty acid synthase inhibitor cerulenin, showed aberrant expression of fatty acid biosynthetic (fab) genes and fatty acid oxidative (fad) genes, produced smaller colonies on agar media, and grew slower in rich broth than did the wild-type parent. Deletion of fadR essentially recapitulated the phenotypes of the insertion mutant, and the DeltafadR mutation was complemented in trans with the wild-type gene. Further characterization of the DeltafadR mutant showed that it was not generally hypersensitive to envelope stresses but had decreased motility and showed an altered membrane lipid profile compared to that of the wild type. Supplementation of broth with the unsaturated fatty acid oleate restored wild-type growth in vitro, and infection with oleate in the inoculum increased the ability of the DeltafadR mutant to infect mice. We conclude that fadR and regulation of fatty acid metabolism are essential for V. vulnificus to be able to cause disease in mammalian hosts.     

Effect of Substrate and Cell Surface Hydrophobicity on Phosphate Utilization in Bacteria

We measured the rates of utilization of hydrophobic and hydrophilic phosphate compounds in gram-negative bacteria with different surface hydrophobicities, isolated from wetland habitats. Three hydrophobic and two hydrophilic bacterial species were selected for study by measuring cell adherence to hydrocarbons. The bacteria were grown under phosphorus-limited conditions with P(infi), hydrophilic (beta)-glycerophosphate, or hydrophobic phosphatidic acid as the phosphate source. Hydrophilic bacteria grew most rapidly on P(infi), followed by (beta)-glycerophosphate. Phosphatidic acid did not support growth or did so at a much later time (40 h) than did the other phosphate treatments. Although all hydrophobic species grew well on these substrates, the rate of growth of two Acinetobacter baumannii isolates on phosphatidic acid exceeded the rate of growth on phosphate or (beta)-glycerophosphate. A membrane phospholipid and lipopolysaccharide were used as a source of phosphorus by hydrophobic species, whereas hydrophilic species could not use the membrane phospholipids and used lipopolysaccharide to a lesser extent. Besides hydrophobic interaction between cells and substrate, phosphatase activity, which was cell bound in hydrophilic species but 30 to 50% unbound in hydrophobic species, affected cell growth. Dialyzed culture supernatant containing phosphatase from hydrophobic species increased the phosphate availability to hydrophilic species. Additionally, cellular extracts from a hydrophilic species, when added to hydrophilic cells, permitted growth on hydrophobic phosphate sources. Naturally occurring amphiphilic humic acids affected the utilization of P(infi) and (beta)-glycerophosphate in bacteria with hydrophilic surfaces but did not affect hydrophobic bacteria. Our results indicate that hydrophobic phosphate sources can be used by bacteria isolated from aquatic environments as the sole phosphorus source for growth. This utilization, in part, appears to be related to cell surface hydrophobicity and extracellular enzyme production.     

Normal mouse serum contains peptides which induce fibroblasts to grow in soft agar

The untransformed mouse fibroblast cells NIH/3T3, C3H/10T1/2, and rat NRK cells do not grow in soft agar in medium supplemented with 10% fetal calf serum. When fetal calf serum in the growth medium was supplemented with less than 1% of sera from mice or other vertebrates, however, these cells responded, forming large colonies. The morphology of soft agar colonies was a function of the treated cell type. In the presence of 10% serum from C57BL/6 mice, NRK cells grew to smooth-surfaced spherical colonies, while NIH/3T3 colonies showed individual round cells on their surface and C3H/10T1/2 cells grew as extended cells forming columns of end to end connected fibroblasts. Mus Musculus Castaneus-Epithelial (MMC- E) cells were not stimulated to grow in soft agar under these conditions. The major fibroblast colony-inducing factor (F-CIF) was partially purified from mouse serum by acid/ethanol-extraction, gel permeation chromatography, and reverse-phase high-pressure liquid chromatography. F-CIF is a polypeptide, which does not compete for binding to epidermal growth factor (EGF) receptors, but stimulates normal fibroblasts to form small colonies in semisolid medium and very large colonies in the presence of added EGF (2 ng/ml). In contrast to unfractionated mouse serum, purified F-CIF did not induce C3H/10T1/2 cells to grow in soft agar, suggesting that serum contains additional cell type-specific agar growth-stimulating activities.     

Group B streptococcal opacity variants.

Colony opacity variants were detected for type III group B streptococci (GBS). Transparent colonies predominate in the parent GBS, with occasional colonies having opaque portions. Two stable opaque variants (1.1 and 1.5) were compared with three transparent clones (1.2, 1.3, and 1.4). All grew well on blood agar and on GC medium, but variant 1.1 failed to grow on Todd-Hewitt medium. Scanning and transmission electron microscopy demonstrated that colony opacity correlated with bacterial aggregation status, with opaque variants forming longer and more organized chains. Opaque-transparent switches were observed in both directions for most variants, with transparent to opaque noted most frequently, but 1.5 did not switch at all. Switching of the opacity phenotype was observed both in vitro and in neonatal mice. Relationships between colony opacity and several cell surface phenomena were explored. (i) Opaque variant 1.1 had two surface proteins (46 and 75 kDa) that were either unique or greatly overexpressed. (ii) Variant 1.1 was deficient in type III polysaccharide, while 1.5 lacked group B antigen. Diminished capsular polysaccharide of variant 1.1 was reflected in reduced negative electrophoretic mobility and in increased buoyant density. (iii) Transparent variant colonies growing closest to a penicillin disk were opaque, but colonial variants did not differ in their sensitivity to penicillin. These data indicate that GBS can exist in both opaque and transparent forms, with opaque appearance occurring by multiple routes. Opaque variants grow poorly on Todd-Hewitt medium generally used for isolation of GBS, so any possible relationships between opacity variation and pathogenesis of GBS infection are unknown.     

Encapsulation of coagulase-negative staphylococci of bovine origin

Capsule expression was assessed in six coagulase-negative staphylococcal strains in serum-soft agar and by india ink and electron microscopy. Classification of strains as encapsulated by serum-soft agar and india ink methods differed. Staphylococcus chromogenes, Staph. hyicus , and Staph. simulans grew as diffuse colonies in serum-soft agar and unstained halos were detected in india ink preparations. Staphylococcus hominis and Staph. simulans grew as diffuse colonies in serum-soft agar but no unstained halo was seen in india ink preparations. Staphylococcus hyicus was the only strain that gave negative results with serum-soft agar and india ink assays. Conventional electron microscopy revealed the presence of capsular polysaccharides on the cell surface of Staph. chromogenes, Staph. hominis and Staph. hyicus. Conventional electron microscopic technique used to examine the surface of cells was detrimental to capsule structure. During dehydration the capsule collapsed and appeared as electron dense aggregates at the surface of cells. To confirm results of conventional electron microscopy and to visualize clearly the cell surface, encapsulated Staph. hyicus and unencapsulated Staph. simulans were observed after freeze-fracture and etching by scanning electron microscopy. The fibrous nature of capsular polysaccharides surrounding cells of Staph. hyicus were distinct and confirmed observation by conventional electron microscopy. A rapid transmission electron microscopic technique is described also for observation of capsule. Results of the rapid TEM method agreed with conventional TEM and SEM. The finding that coagulase-negative staphylococci isolated from bovine milk are capable of capsule production may be important when investigating pathogenicity of these micro-organisms.     

Encapsulation of coagulase-negative staphylococci of bovine origin.

Capsule expression was assessed in six coagulase-negative staphylococcal strains in serum-soft agar and by india ink and electron microscopy. Classification of strains as encapsulated by serum-soft agar and india ink methods differed. Staphylococcus chromogenes, Staph. hyicus, and Staph. simulans grew as diffuse colonies in serum-soft agar and unstained halos were detected in india ink preparations. Staphylococcus hominis and Staph. simulans grew as diffuse colonies in serum-soft agar but no unstained halo was seen in india ink preparations. Staphylococcus hyicus was the only strain that gave negative results with serum-soft agar and india ink assays. Conventional electron microscopy revealed the presence of capsular polysaccharides on the cell surface of Staph. chromogenes, Staph. hominis and Staph. hyicus. Conventional electron microscopic technique used to examine the surface of cells was detrimental to capsule structure. During dehydration the capsule collapsed and appeared as electron dense aggregates at the surface of cells. To confirm results of conventional electron microscopy and to visualize clearly the cell surface, encapsulated Staph. hyicus and unencapsulated Staph. simulans were observed after freeze-fracture and etching by scanning electron microscopy. The fibrous nature of capsular polysaccharides surrounding cells of Staph. hyicus were distinct and confirmed observation by conventional electron microscopy. A rapid transmission electron microscopic technique is described also for observation of capsule. Results of the rapid TEM method agreed with conventional TEM and SEM. The finding that coagulase-negative staphylococci isolated from bovine milk are capable of capsule production may be important when investigating pathogenicity of these micro-organisms.     

Biological properties of "partial" transformation mutants of Rous sarcoma virus and characterization of their pp60src kinase

We have isolated mutants of Rous sarcoma virus from an unmutagenized stock of the Schmidt-Ruppin strain of Rous sarcoma virus. These mutants induce only a "partial" transformation, and the transformation properties induced show unusual properties or combinations. Cells infected with mutant CU2 have a unique "blebby" morphology, have lost surface fibronectin, form very small colonies in soft agar, and are nearly normal with respect to adhesiveness and hexose transport. Cells infected with mutant tsCU11 have a nearly normal morphology, but grow well in soft agar. Cells infected with mutant CU12 have a fusiform morphology, intermediate levels of hexose transport and fibronectin, and form very large colonies in soft agar. Because the appearance of the different parameters of transformation is dissociated in these mutant-infected cells, these data are interpreted as supporting a model in which the transforming protein pp60src interacts with more than one primary target in generating the transformed phenotype. All of the mutants display levels of pp60src kinase activity less than that of the wild type. In the case of mutant CU12, the lower kinase activity is in part a consequence of a lower steady-state amount of pp60src inside the cell.     

tsJT60, a cell cycle G0-ts mutant, becomes lethal at non-permissive temperature by transformation with adenovirus 5 when the expression of E1B gene is lacking

tsJT60, a temperature-sensitive (ts) mutant cell line of Fischer rat, is viable at both permissive (34 degrees C) and non-permissive (39.5 degrees C) temperatures. The cells grow normally in exponential growth phase at both temperatures, but when stimulated with fetal bovine serum (FBS) from G0 phase they re-enter S phase at 34 degrees C but not at 39.5 degrees. When tsJT60 cells were transformed with adenovirus (Ad) 5 wild type, they grew well at both temperatures, expressed E1A and E1B genes, and formed colonies in soft agar. When tsJT60 cells were transformed with Ad5 dl313, that lacks E1B gene, the transformed cells grew well at 34 degrees C but failed to form colony in soft agar. They died very soon at 39.5 degrees C. 3Y1 cells (a parental line of tsJT60) transformed with dl313 grew well at both temperatures, although neither expressed E1B gene nor formed colonies in soft agar. The phenotype of being lethal at 39.5 degrees C of dl313-transformed tsJT60 cells was complemented by cell fusion with 3Y1BUr cells (5-BrdU-resistant 3Y1), but not with tsJT60TGr cells (6-thioguanine resistant tsJT60). These results indicate that the lethal phenotype is related to the ts mutation of tsJT60 cells and also to the deletion of E1B gene of Ad5.     

Adhesion of the entomopathogenic fungus Beauveria (Cordyceps) bassiana to substrata

The entomopathogenic fungus Beauveria bassiana produces at least three distinct single-cell propagules, aerial conidia, vegetative cells termed blastospores, and submerged conidia, which can be isolated from agar plates, from rich broth liquid cultures, and under nutrient limitation conditions in submerged cultures, respectively. Fluorescently labeled fungal cells were used to quantify the kinetics of adhesion of these cell types to surfaces having various hydrophobic or hydrophilic properties. Aerial conidia adhered poorly to weakly polar surfaces and rapidly to both hydrophobic and hydrophilic surfaces but could be readily washed off the latter surfaces. In contrast, blastospores bound poorly to hydrophobic surfaces, forming small aggregates, bound rapidly to hydrophilic surfaces, and required a longer incubation time to bind to weakly polar surfaces than to hydrophilic surfaces. Submerged conidia displayed the broadest binding specificity, adhering to hydrophobic, weakly polar, and hydrophilic surfaces. The adhesion of the B. bassiana cell types also differed in sensitivity to glycosidase and protease treatments, pH, and addition of various carbohydrate competitors and detergents. The outer cell wall layer of aerial conidia contained sodium dodecyl sulfate-insoluble, trifluoroacetic acid-soluble proteins (presumably hydrophobins) that were not present on either blastospores or submerged conidia. The variations in the cell surface properties leading to the different adhesion qualities of B. bassiana aerial conidia, blastospores, and submerged conidia could lead to rational design decisions for improving the efficacy and possibly the specificity of entomopathogenic fungi for host targets.     

Characterization of CMP-N-acetylneuraminic acid synthetase of group B streptococci.

The capsular polysaccharide is a critical virulence factor for group B streptococci associated with human infections, yet little is known about capsule biosynthesis. We detected CMP-Neu5Ac synthetase, the enzyme which activates N-acetylneuraminic acid (Neu5Ac, or sialic acid) for transfer to the nascent capsular polysaccharide, in multiple group B streptococcus serotypes, all of which elaborate capsules containing Neu5Ac. CMP-Neu5Ac synthetase isolated from a high-producing type Ib strain was purified 87-fold. The enzyme had apparent Km values of 7.6 for Neu5Ac and 1.4 for CTP and a pH optimum of 8.3 to 9.4, required magnesium, and was stimulated by dithiothreitol. This is the first characterization of an enzyme involved in group B streptococcus capsular polysaccharide biosynthesis.     

A mutant v-rel with increased ability to transform B lymphocytes.

We observed that two strains of REV-T differ in the ability to transform bursal cells in vitro. REV-TW, with v-rel derived from a well-characterized clone and considered the prototype of the wild type, fails to generate colonies in soft agar. In contrast, REV-S2A3, derived from the S2A3 cell line, readily transforms bursal cells. With PCR, a 1,591-bp fragment containing v-rel from the REV-S2A3 provirus was cloned into plasmid pREV-0. Except for the absence of v-rel, pREV-0 is identical to pREV-TW. Five clones of pREV-PCR, each produced by an independent amplification, were obtained. The REV-PCR viruses displayed the strong transforming phenotype of REV-S2A3. Two mutations were identified in the 5' region of v-rel from REV-PCR1 to REV-PCR5: a silent mutation and a G-to-T transversion, changing the alanine at position 40 to serine. To confirm the relevance of this amino acid substitution, a 478-bp fragment containing the mutations was exchanged between REV-TW and REV-PCR1. Only the mutant viruses were able to form large colonies of bursal cells in liquid culture and to generate bursal cell colonies in soft agar. When tested on splenocytes, the wild-type viruses induced predominantly non-B-cell colonies while the mutant viruses gave origin mainly to B-cell colonies. The above results indicate that the substitution of serine for alanine at position 40 of v-Rel enhances the ability of REV-T to transform B lymphocytes in vitro. This mutation is close to the DNA-binding region, and the variant v-Rel oncoprotein shows increased kappa B-binding activity, thus confirming the relevance of this property for transformation.     

A comparison of 2 methods for determining the hydrophobicity of Streptococcus groups A and B

A simple method for the evaluation of the hydrophobic properties of streptococci, pathogenic for humans, by their adherence to polystyrene and a modified method for measuring their hydrophobic properties by their sorption on hexadecane have been developed. The results obtained in the evaluation of the hydrophobic properties of streptococci by these two methods have been compared and the complete correlation of these results in classifying the cultures as hydrophobic and hydrophilic has been shown. For the first time the differences in the hydrophobic properties of different strains of group B streptococci have been established.     

Adhesion of the Entomopathogenic Fungus Beauveria (Cordyceps) bassiana to Substrata

The entomopathogenic fungus Beauveria bassiana produces at least three distinct single-cell propagules, aerial conidia, vegetative cells termed blastospores, and submerged conidia, which can be isolated from agar plates, from rich broth liquid cultures, and under nutrient limitation conditions in submerged cultures, respectively. Fluorescently labeled fungal cells were used to quantify the kinetics of adhesion of these cell types to surfaces having various hydrophobic or hydrophilic properties. Aerial conidia adhered poorly to weakly polar surfaces and rapidly to both hydrophobic and hydrophilic surfaces but could be readily washed off the latter surfaces. In contrast, blastospores bound poorly to hydrophobic surfaces, forming small aggregates, bound rapidly to hydrophilic surfaces, and required a longer incubation time to bind to weakly polar surfaces than to hydrophilic surfaces. Submerged conidia displayed the broadest binding specificity, adhering to hydrophobic, weakly polar, and hydrophilic surfaces. The adhesion of the B. bassiana cell types also differed in sensitivity to glycosidase and protease treatments, pH, and addition of various carbohydrate competitors and detergents. The outer cell wall layer of aerial conidia contained sodium dodecyl sulfate-insoluble, trifluoroacetic acid-soluble proteins (presumably hydrophobins) that were not present on either blastospores or submerged conidia. The variations in the cell surface properties leading to the different adhesion qualities of B. bassiana aerial conidia, blastospores, and submerged conidia could lead to rational design decisions for improving the efficacy and possibly the specificity of entomopathogenic fungi for host targets.