The <Emphasis Type="Italic">Adh</Emphasis> locus and adaptation of <Emphasis Type="Italic">cn</Emphasis> and <Emphasis Type="Italic">vg</Emphasis> mutants in experimental populations of <Emphasis Type="Italic">Drosophila melanogaster MEIG</Emphasis>

A complex study on the adaptation of cn and vn mutants and the allozymes of alcoholdehydrogenase (ADH) was carried out in initially pure lines, and their panmixia populations during exchange of the mutant genotype with that of wild-type flies (C-S) and D) through saturating crossings. The relative adaptation of the genotypes was estimated by their effect on reproductive efficiency in the experimentally obtained population. Fecundity, lifespan, and the resistance of the studied genotypes to hyperthermia were investigated individually. It was shown that the high level of adaptation of the cn mutants and the low level of adaptation of the vg mutants was correlated with the presence of different ADH allozymes. In the studied population, the F-allozyme of ADH accompanied the vg mutation, while the S-allozyme of the enzyme was detected in cn mutants. Saturating crossings of C-S(Adh ^S)×vg(Adh ^F) and D(Adh ^F) × cn(Adh ^S), along with the parallel determination of the allele composition of the Adh locus, demonstrated that the complete substitution of the F-allozyme of ADH in the vg mutants by the S-allozyme in D flies, as well as the substitution of the S-allozyme of ADH in the cn mutants by the F-allozyme in D flies was realized only after the 15th–20th backcrosses. These results favor the coadaptation of cn and vg marker genes with alleles of the Adh locus and indicate the important role of the latter in the adaptation of genotypes. In the studied population, selection acted primarily against the vg mutants, which were inferior to the cn mutants, and heterozygote genotypes in indices of the main adaptation components.     

A putative <Emphasis Type="Italic">NEM1</Emphasis> homologue regulates lipid droplet biogenesis <Emphasis Type="Italic">via PAH1</Emphasis> in <Emphasis Type="Italic">Tetrahymena thermophila</Emphasis>

Nuclear envelope morphology protein 1 (NEM1) along with a phosphatidate phosphatase (PAH1) regulates lipid homeostasis and membrane biogenesis in yeast and mammals. We investigated four putative NEM1 homologues (TtNEM1A, TtNEM1B, TtNEM1C and TtNEM1D) in the Tetrahymena thermophila genome. Disruption of TtNEM1B, TtNEM1C or TtNEM1D did not compromise normal cell growth. In contrast, we were unable to generate knockout strain of TtNEM1A under the same conditions, indicating that TtNEM1A is essential for Tetrahymena growth. Interestingly, loss of TtNEM1B but not TtNEM1C or TtNEM1D caused a reduction in lipid droplet number. Similar to yeast and mammals, TtNem1B of Tetrahymena exerts its function via Pah1, since we found that PAH1 overexpression rescued loss of Nem1 function. However, unlike NEM1 in other organisms, TtNEM1B does not regulate ER/nuclear morphology. Similarly, neither TtNEM1C nor TtNEM1D is required to maintain normal ER morphology. While Tetrahymena PAH1 was shown to functionally replace yeast PAH1 earlier, we observed that Tetrahymena NEM1 homologues did not functionally replace yeast NEM1. Overall, our results suggest the presence of a conserved cascade for regulation of lipid homeostasis and membrane biogenesis in Tetrahymena. Our results also suggest a Nem1-independent function of Pah1 in the regulation of ER morphology in Tetrahymena.     

<Emphasis Type="Italic">LMI1</Emphasis>-like genes involved in leaf margin development of <Emphasis Type="Italic">Brassica napus</Emphasis>

In rapeseed (Brassica napus L.), leaf margins are variable and can be entire, serrate, or lobed. In our previous study, the lobed-leaf gene (LOBED-LEAF 1, BnLL1) was mapped to a 32.1 kb section of B. napus A10. Two LMI1-like genes, BnaA10g26320D and BnaA10g26330D, were considered the potential genes that controlled the lobed-leaf trait in rapeseed. In the present study, these two genes and another homologous gene (BnaC04g00850D) were transformed into Arabidopsis thaliana (L.) Heynh. plants to identify their functions. All three LMI1-like genes of B. napus produced serrate leaf margins. The expression analysis indicated that the expression level of BnaA10g26320D determined the difference between lobed- and entire-leaved lines in rapeseed. Therefore, it is likely that BnaA10g26320D corresponds to BnLL1.     

The endosymbiont <Emphasis Type="Italic">Wolbachia</Emphasis> in Eurasian populations of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

The endosymbiotic α-proteobacteria Wolbachia is widely spread among arthropods and Filariidae nematodes. This bacterium is transmitted vertically via a transovarian route. Wolbachia is a cause of several reproductive abnormalities in the host species. We analyzed the isofemale lines created using flies collected from Drosophila melanogaster natural populations for infection with the endosymbiont Wolbachia. Wolbachia were genotyped according to five variable markers: the presence of insertion sequence IS5 in two loci, the copy number of two minisatellite repeats, and an inversion. Overall, 665 isofemale lines isolated from the populations of D. melanogaster from Ukraine, Belarus, Moldova, Caucasus, Central Asia, Ural, Udmurtia, Altai, West and East Siberia, and Far East in 1974 through 2005 were used in the work. The samples from Ukrainian, Altaian, and Middle Asian populations were largest. The infection rate of D. melanogaster populations from Middle Asia, Altaian, and Eastern Europe (Ukraine, Moldavia, and Belarus) with Wolbachia amounted to 64, 56, and 39%, respectively. The D. melanogaster population from the Caucasus displayed heterogeneity in the genotypes of this cytoplasmic infection. The Wolbachia genotype wMel, detected in all the populations studied, was the most abundant. The genotype wMelCS2 was always present in the populations from Middle Asia and Altai and was among the rare variants in the D. melanogaster populations from the Eastern Europe. Single instances of the Wolbachia genotype wMelCS occurred in a few flies from the Central Asian and Altai populations, but was not found this genotype in the other regions.     

Regulatory activity of heterologous gene-activator <Emphasis Type="Italic">xlnR</Emphasis> of <Emphasis Type="Italic">Aspergillus niger</Emphasis> in <Emphasis Type="Italic">Penicillium canescens</Emphasis>

The gene encoding the xlnR xylanolytic activator of the heterologous fungus Aspergillus niger was incorporated into the Penicillium canescens genome. Integration of the xlnR gene resulted in the increase in a number of activities, i.e. endoxylanase, β-xylosidase, α-L-arabinofuranosidase, α-galactosidase, and feruloyl esterase, compared to the host P. canescens PCA 10 strain, while β-galactosidase, β-glucosidase, endoglucanase, and CMCase activities remained constant. Two different expression constructs were developed. The first consisted of the nucleotide sequence containing the mature P. canescens phytase gene under control of the axhA promoter region gene encoding A. niger (1,4)-β-D-arabinoxylan-arabinofuranohydrolase. The second construct combined the P. canescens phytase gene and the bgaS promoter region encoding homologous β-galactosidase. Both expression cassettes were transformed into P. canescens host strain containing xlnR. Phytase synthesis was observed only for strains with the bgaS promoter on arabinose-containing culture media. In conclusion, the bgaS and axhA promoters were regulated by different inducers and activators in the P. canescens strain containing a structural tandem of the axhA promoter and the gene of the xlnR xylanolytic activator.     

Neuro-and psychotropic activity of <Emphasis Type="Italic">N</Emphasis>-uronoylamino acids and <Emphasis Type="Italic">N</Emphasis>-uronoylpeptides

Peculiarities of the rat behavior were studied in a series of experimental stress models after a systemic administration of new N-uronoyl derivatives of amino acids. The psychotropic effect was shown to be determined by the nature of the amino acid fragment. N-(1,2:3,4-Di-O-isopropylidene-α-D-galactopyraneuronoyl)-glycylglycine exhibited an anxiolytic effect more pronounced than that of pyracetam, whereas N-(1,2:3,4-di-O-isopropilidene-α-D-galactopyranuronoyl)-glycylglutamic acid has antidepressant action stronger than that of amitriptyline. Mechanisms for the psychotropic effects of the examined derivatives are discussed.     

Association between expression levels and growth trait-related SNPs located in promoters of the <Emphasis Type="Italic">MC4R</Emphasis> and <Emphasis Type="Italic">MSTN</Emphasis> genes in <Emphasis Type="Italic">Spinibarbus hollandi</Emphasis>

Melanocortin 4 receptor: (MC4R) and Myostatin (MSTN) are two important growth trait-related genes in animals. In this study, we showed that two SNPs, MC4R-719A>G and MSTN-519C>T, found in the promoters of the MC4R and MSTN genes, respectively, are both associated with growth traits in Spinibarbus hollandi. Furthermore, we observed that there were significant associations between the expression levels of the MC4R and MSTN genes and these two growth trait-related SNPs. The expression level of MC4R gene in brain was lower in GG genotype fish with extremely high growth performance than that in AA genotype fish with extremely low growth performance. Expression level of the MSTN gene in muscle was lower in TT genotype fish with extremely high growth performance than that in CC and CT genotype fish with lower growth performance. The results indicated that these SNPs located in the promoters of MC4R and MSTN are associated with growth-related traits through modification of gene expression levels. The MSTN and MC4R SNPs may have useful application in effective marker-assisted selection aimed to increase output in S. hollandi.     

Polymorphic variants of glutamate receptor (<Emphasis Type="Italic">GRIK5</Emphasis>, <Emphasis Type="Italic">GRIN2B</Emphasis>) and serotonin receptor (<Emphasis Type="Italic">HTR2A</Emphasis>) genes are associated with chronic

Chronic obstructive pulmonary disease (COPD) is a complex chronic inflammatory disease of the respiratory system that affects primarily distal respiratory pathways and lung parenchyma. Smoking tobacco is a major risk factor for COPD. The relationship of HTR4 (rs3995090), HTR2A (rs6313), GRIK5 (rs8099939), GRIN2B (rs2268132), and CHRNB4 (rs1948) gene polymorphisms and COPD, as well as the contribution of these polymorphisms to the variations in quantitative characteristics that describe respiratory function, smoking behavior, and nicotine dependence was assessed in an ethnically homogeneous Tatar population. The polymorphisms of HTR2A (rs6313) (P = 0.026, OR = 1.42 for the CC genotype) and GRIN2B (rs2268132) (P = 0.0001, OR = 2.39 for the TT genotype) were significantly associated with increased risk of COPD. The AA genotype of GRIK5 (rs8099939) had a protective effect (P = 0.02, OR = 0.61). Importantly, the HTR2A (rs6313), GRIN2B (rs2268132), and GRIK5 (rs8099939) polymorphisms were only associated with COPD in smokers. Smoking index (pack-years) was significantly higher in carriers of the GRIK5 genotype AC (rs8099939) (P = 0.0027). The TT genotype of GRIN2B (rs2268132) was associated with COPD in subjects with high nicotine dependence according to the Fagerström test (P = 0.002, OR = 2.98). The TT genotype of HTR2A (rs6313) was associated with a reduced risk of the disease in the group with moderate nicotine dependence (P = 0.02, OR = 0.22). The CC genotype of HTR2A (rs6313) and the TT genotype of GRIN2B (rs2268132) were associated with higher levels of nicotine dependence according to the Fagerström test (P = 0.0011 and P = 0.037). Our results may provide insight into potential molecular mechanisms that involve the glutamate (GRIK5, GRIN2B) and serotonin (HTR2A) receptor genes in the pathogenesis of COPD.     

The <Emphasis Type="Italic">angora</Emphasis> gene weakens the effect of interaction of the mutant genes <Emphasis Type="Italic">wellhaarig</Emphasis> and <Emphasis Type="Italic">waved alopecia</Emphasis> in mice

The interaction of the mutant genes wellhaarig (we) and waved alopecia (wal) in mice was earlier demonstrated in our laboratory. The we gene significantly accelerates the appearance of alopecia in double we/wewal/wal homozygotes as compared to that in single +/+wal/wal homozygotes. It has been found in this work that the mutant gene angora-Y (Fgf5 ^go-Y ) weakens the effect of interaction of the we and wal genes. The first signs of alopecia appear in mice of the we/wewal/wal genotype at the age of 14 days, in triple Fgf5 ^go-Y /Fgf5 ^go-Y we/wewal/wal homozygotes alopecia is observed seven days later, i. e., in 21-day-old animals. The progression of alopecia in triple homozygotes is expressed to a lesser degree than in double +/+we/wewal/wal homozygotes. A single dose of the Fgf5 ^go-Y gene also decreases the effect of interaction of the we and wal genes, but less than a double dose of this gene. The first signs of alopecia in mice of the +/Fgf5 ^go-Y we/wewal/wal genotype appear only three days later than in double +/+we/wewal/wal homozygotes. The data obtained demonstrate that the Fgf5 ^go-Y gene is a powerful modifier of mutant genes determining the process of alopecia.     

Toxin Gene Contents and Activity of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> Strains Against Two Sugarcane Borer Species, <Emphasis Type="Italic">Diatraea saccharalis</Emphasis> (F.) and <Emphasis Type="Italic">D. flavipennella</Emphasis> (Box)

Bacillus thuringiensis (Berliner) bears essential characteristics in the control of insect pests, such as its unique mode of action, which confers specificity and selectivity. This study assessed cry gene contents from Bt strains and their entomotoxicity against Diatraea saccharalis (F.) and Diatraea flavipennella (Box) (Lepidoptera: Crambidae). Bioassays with Bt strains were performed against neonates to evaluate their lethal and sublethal activities and were further analyzed by PCR, using primers to identify toxin genes. For D. saccharalis and D. flavipennella, 16 and 18 strains showed over 30% larval mortality in the 7th day, respectively. The LC₅₀ values of strains for D. saccharalis varied from 0.08 × 10⁵ (LIIT-0105) to 4104 × 10⁵ (LIIT-2707) spores + crystals mL^?1. For D. flavipennella, the LC₅₀ values of strains varied from 0.40 × 10⁵ (LIIT-2707) to 542 × 10⁵ (LIIT-2109) spores + crystals mL^?1. For the LIIT-0105 strain, which was the most toxic to D. saccharalis, the genes cry1Aa, cry1Ab, cry1Ac, cry1B, cry1C, cry1D, cry1F, cry1I, cry2Aa, cry2Ab, cry8, and cry9C were detected, whereas for the strain LIIT-2707, which was the most toxic to D. flavipennella, detected genes were cry1Aa, cry1Ab, cry1Ac, cry1B, cry1D, cry1F, cry1I, cry2Aa, cry2Ab, and cry9. The toxicity data and toxin gene content in these strains of Bt suggest a great variability of activity with potential to be used in the development of novel biopesticides or as source of resistance genes that can be expressed in plants to control pests.     

Steroid Compounds from Far Eastern Starfishes <Emphasis Type="Italic">Henricia aspera</Emphasis> and <Emphasis Type="Italic">H. tumida</Emphasis>

Six new natural compounds were isolated from two Far Eastern starfish species, Henricia aspera and H. tumida, collected in the Sea of Okhotsk. Two new glycosylated steroid polyols were obtained from H. aspera: asperoside A and asperoside B, which were shown to be (20R,24R, 25S)-3-O-(2,3-di-O-methyl-β -D-xylopyranosyl)-24-methyl-5α-cholest-4-ene-3β, 6β,8,15α,16β,26-hexaol and (20R, 24R,25S,22E)-3-O-(2,4-di-O-methyl-β-D-xylopyranosyl)-24-methyl-5α-cholest-22-ene-3β,4β,6β,8,15α,26-hexaol, respectively. Two other glycosylated polyols, tumidoside A, with the structure elucidated as (20R, 22E)-3-O-(2,4-di-O-methyl-β -D-xylopyranosyl)-26,27-dinor-24-methyl-5α-cholest-22-ene-3β,4β,6β,8,15α,25-hexaol, and tumidoside B, whose structure was elucidated as (20R,24S)-3-O-(2,3-di-O-methyl-β-D-xylopyranosyl)-5α-cholestan-3β,4β,6β,8,15α,24-hexaol, were isolated from the two starfish species. (20R, 24S)-5α-Cholestan-3β,6β,15α,24-tetraol and (20R, 24S)-5α-cholestan-3β,6β,8,15α,24-pentaol were identified only in H. tumida. The known monoglycosides henricioside H1 and laeviuscolosides H and G were also identified in both species.     

Bacterial metabolites from intra- and inter-species influencing thermotolerance: the case of <Emphasis Type="Italic">Bacillus cereus</Emphasis> and <Emphasis Type="Italic">Geobacillus stearothermophilus</Emphasis>

Bacterial metabolites with communicative functions could provide protection against stress conditions to members of the same species. Yet, information remains limited about protection provided by metabolites in Bacillus cereus and inter-species. This study investigated the effect of extracellular compounds derived from heat shocked (HS) and non-HS cultures of B. cereus and Geobacillus stearothermophilus on the thermotolerance of non-HS vegetative and sporulating B. cereus. Cultures of B. cereus and G. stearothermophilus were subjected to HS (42 or 65 °C respectively for 30 min) or non-HS treatments. Cells and supernatants were separated, mixed in a combined array, and then exposed to 50 °C for 60 min and viable cells determined. For spores, D values (85 and 95 °C) were evaluated after 120 h. In most cases, supernatants from HS B. cereus cultures added to non-HS B. cereus cells caused their thermotolerance to increase (D ₅₀ 12.2–51.9) when compared to supernatants from non-HS cultures (D ₅₀ 7.4–21.7). While the addition of supernatants from HS and non-HS G. stearothermophilus cultures caused the thermotolerance of non-HS cells from B. cereus to decrease initially (D ₅₀ 3.7–7.1), a subsequent increase was detected in most cases (D ₅₀ 18–97.7). In most cases, supernatants from sporulating G. stearothermophilus added to sporulating cells of B. cereus caused the thermotolerance of B. cereus 4810 spores to decline, whereas that of B. cereus 14579 increased. This study clearly shows that metabolites in supernatants from either the same or different species (such as G. stearothermophilus) influence the thermotolerance of B. cereus.     

Constitutive expression of <Emphasis Type="Italic">SlTrxF</Emphasis> increases starch content in transgenic <Emphasis Type="Italic">Arabidopsis</Emphasis>

The plastidic thioredoxin F-type (TrxF) protein plays an important role in plant saccharide metabolism. In this study, a gene encoding the TrxF protein, named SlTrxF, was isolated from tomato. The coding region of SlTrxF was cloned into a binary vector under the control of 35S promoter and then transformed into Arabidopsis thaliana. The transgenic Arabidopsis plants exhibited increased starch accumulation compared to the wild-type (WT). Real-time quantitative PCR analysis showed that constitutive expression of SlTrxF up-regulated the expression of ADP-glucose pyrophosphorylase (AGPase) small subunit (AtAGPase-S1 and AtAGPase-S2), AGPase large subunit (AtAGPase-L1 and AtAGPase-L2) and soluble starch synthase (AtSSS I, AtSSS II, AtSSS III and AtSSS IV) genes involved in starch biosynthesis in the transgenic Arabidopsis plants. Meanwhile, enzymatic analyses showed that the major enzymes (AGPase and SSS) involved in the starch biosynthesis exhibited higher activities in the transgenic plants compared to WT. These results suggest that SlTrxF may improve starch content of Arabidopsis by regulating the expression of the related genes and increasing the activities of the major enzymes involved in starch biosynthesis.     

Secreted proteins produced by fungi associated with <Emphasis Type="Italic">Botryosphaeria</Emphasis> dieback trigger distinct defense responses in <Emphasis Type="Italic">Vitis vinifera</Emphasis> and <Emphasis Type="Italic">Vitis rupestris</Emphasis> cells

Grapevine trunk diseases (Eutypa dieback, esca and Botryosphaeria dieback) are caused by a complex of xylem-inhabiting fungi, which severely reduce yields in vineyards. Botryosphaeria dieback is associated with Botryosphaeriaceae. In order to develop effective strategies against Botryosphaeria dieback, we investigated the molecular basis of grapevine interactions with a virulent species, Neofusicoccum parvum, and a weak pathogen, Diplodia seriata. We investigated defenses induced by purified secreted fungal proteins within suspension cells of Vitis (Vitis rupestris and Vitis vinifera cv. Gewurztraminer) with putative different susceptibility to Botryosphaeria dieback. Our results show that Vitis cells are able to detect secreted proteins produced by Botryosphaeriaceae, resulting in a rapid alkalinization of the extracellular medium and the production of reactive oxygen species. Concerning early defense responses, N. parvum proteins induced a more intense response compared to D. seriata. Early and late defense responses, i.e., extracellular medium alkalinization, cell death, and expression of PR defense genes were stronger in V. rupestris compared to V. vinifera, except for stilbene production. Secreted Botryosphaeriaceae proteins triggered a high accumulation of δ-viniferin in V. vinifera suspension cells. Artificial inoculation assays on detached canes with N. parvum and D. seriata showed that the development of necrosis is reduced in V. rupestris compared to V. vinifera cv. Gewurztraminer. This may be related to a more efficient induction of defense responses in V. rupestris, although not sufficient to completely inhibit fungal colonization. Overall, our work shows a specific signature of defense responses depending on the grapevine genotype and the fungal species.     

Mutation analysis of the <Emphasis Type="Italic">COL1A1</Emphasis> and <Emphasis Type="Italic">COL1A2</Emphasis> genes in Vietnamese patients with osteogenesis imperfecta

Background

The genetics of osteogenesis imperfecta (OI) have not been studied in a Vietnamese population before. We performed mutational analysis of the COL1A1 and COL1A2 genes in 91 unrelated OI patients of Vietnamese origin. We then systematically characterized the mutation profiles of these two genes which are most commonly related to OI.

Methods

Genomic DNA was extracted from EDTA-preserved blood according to standard high-salt extraction methods. Sequence analysis and pathogenic variant identification was performed with Mutation Surveyor DNA variant analysis software. Prediction of the pathogenicity of mutations was conducted using Alamut Visual software. The presence of variants was checked against Dalgleish’s osteogenesis imperfecta mutation database.

Results

The sample consisted of 91 unrelated osteogenesis imperfecta patients. We identified 54 patients with COL1A1/2 pathogenic variants; 33 with COL1A1 and 21 with COL1A2. Two patients had multiple pathogenic variants. Seventeen novel COL1A1 and 10 novel COL1A2 variants were identified. The majority of identified COL1A1/2 pathogenic variants occurred in a glycine substitution (36/56, 64.3 %), usually serine (23/36, 63.9 %). We found two pathogenic variants of the COL1A1 gene c.2461G?>?A (p.Gly821Ser) in four unrelated patients and one, c.2005G?>?A (p.Ala669Thr), in two unrelated patients.

Conclusion

Our data showed a lower number of collagen OI pathogenic variants in Vietnamese patients compared to reported rates for Asian populations. The OI mutational profile of the Vietnamese population is unique and related to the presence of a high number of recessive mutations in non-collagenous OI genes. Further analysis of OI patients negative for collagen mutations, is required.

     

Association of variable <Emphasis Type="Italic">rs1801282</Emphasis> locus of <Emphasis Type="Italic">PPARG2</Emphasis> gene with diabetic nephropathy

The association of the variable rs1801282 locus of the PPARG2 gene (peroxisome proliferator-activated receptor gamma) with type 2 diabetes mellitus and its complications was analyzed in inhabitants of the Republic of Bashkortostan. The genotype frequencies of the variable rs1801282 locus of the PPARG2 gene did not significantly differ in groups of healthy persons and patients with type 2 diabetes in all three considered inheritance models (codominant, dominant, and recessive). At the same time, it was demonstrated that the risk of one of the diabetic complications, i.e., diabetic nephropathy, was associated with the variable rs1801282 locus of the PPARG2 gene. Diabetic nephropathy was more common in patients with the C/C genotype (62.7%) compared to the C/G and G/G genotypes (37.5%), P = 0.036. The G allele is protective in regard to diabetic nephropathy (OR = 0.36) in patients with type 2 diabetes mellitus.     

<Emphasis Type="Italic">Candida krusei</Emphasis> and <Emphasis Type="Italic">Candida glabrata</Emphasis> reduce the filamentation of <Emphasis Type="Italic">Candida albicans</Emphasis> by downregulating expression of <Emphasis Type="Italic">HWP1</Emphasis> gene

Pathogenicity of Candida albicans is associated with its capacity switch from yeast-like to hyphal growth. The hyphal form is capable to penetrate the epithelial surfaces and to damage the host tissues. Therefore, many investigations have focused on mechanisms that control the morphological transitions of C. albicans. Recently, certain studies have showed that non-albicans Candida species can reduce the capacity of C. albicans to form biofilms and to develop candidiasis in animal models. Then, the objective of this study was to evaluate the effects of Candida krusei and Candida glabrata on the morphogenesis of C. albicans. Firstly, the capacity of reference and clinical strains of C. albicans in forming hyphae was tested in vitro. After that, the expression of HWP1 (hyphal wall protein 1) gene was determined by quantitative real-time PCR (polymerase chain reaction) assay. For both reference and clinical strains, a significant inhibition of the hyphae formation was observed when C. albicans was incubated in the presence of C. krusei or C. glabrata compared to the control group composed only by C. albicans. In addition, the culture mixed of C. albicans-C. krusei or C. albicans-C. glabrata reduced significantly the expression of HWP1 gene of C. albicans in relation to single cultures of this specie. In both filamentation and gene expression assays, C. krusei showed the higher inhibitory activity on the morphogenesis of C. albicans compared to C. glabrata. C. krusei and C. glabrata are capable to reduce the filamentation of C. albicans and consequently decrease the expression of the HWP1 gene.