Production of recombinant great sturgeon (Huso huso,Linnaeus, 1758) growth hormone (GH) by Pichia pastoris (Guillierm, 1956)

In this research, the encoding cDNA of growth hormone (GH) was cloned from the pituitary gland of great sturgeon Huso huso (three adults: two females and one male, 7–9 years old, 70–90 kg, reared in concrete ponds). In order to obtain the great sturgeon recombinant GH expression in Pichia pastoris, the mature encoding cDNA was first cloned in TA vector PTZ57R and then sequenced. After confirmation of the correct GH sequence, the GH coding sequence was subcloned into pHILS1 expression vector. The yeast Pichia pastoris GS115 strain was transformed with the expression plasmid. Results obtained from this study showed that great sturgeon GH recombinants were expressed upon induction with methanol and exported into the medium. The level of expression was examined using RNA analysis, SDS‐PAGE, and western blot analysis. RNA analysis of the recombinant strains showed a sharp, specific band in 800 bp. The specific band in transformants indicated the presence of GH RNA in the yeast. SDS‐PAGE and western blot analysis showed a specific 21 kDa band for the growth hormone. Culture conditions were optimized for pH = 6 and incubation time (after 24 h induction, peaking at 72 h) for maximal protein production. The results provide useful information for the future production of recombinant growth hormones in other sturgeon species.     

cDNA sequence and tissues expression analysis of lipoprotein lipase from common carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> Var. Jian)

A full-length cDNA coding lipoprotein lipase (LPL) was cloned from liver of adult common carp (Cyprinus carpio Var. Jian) by RT-PCR and rapid amplification of cDNA ends (RACE) approaches. The cDNA obtained was 2,411 bp long with a 1,524 bp open reading frame (ORF) encoding 507 amino acids. This amino acid sequence contains two structural regions: N-terminus (24–354 residues) and C-terminus (355–507 residues). Before N-terminus, 1–23 residues is signal peptide, 6–23 residues is transmembrance helix. At N-terminus, some conversed functional sites were found, including two N-linked glycosylation sites Asn⁴¹ and Asn⁸⁸; one catalytic triad Ser¹⁷⁴, Asp¹⁹⁸ and His²⁸³; one conserved heparin-binding site Arg³²¹ to Arg³²⁴ (RKNR); eight cysteines residues Cys⁶⁹ and Cys⁸², Cys²⁵⁸ and Cys²⁸¹, Cys³⁰⁶ and Cys³²⁵, Cys³¹⁷ and Cys³²⁰ which are involved in four disulfide bridges; one polypeptide “lid” that participates in substrate specificity. At C-terminus, Asn⁴⁰¹ is another N-linked glycosylation site, and Trp⁴³⁴ and Trp⁴³⁵ (WW) is lipid-binding site. The amino acid sequence has a high similarity, and shows similar structural features to LPL of other species. Tissue distribution of LPL mRNA in liver, head kidney, mesenteric adipose tissue, heart and white muscle of common carp was analyzed by semi-quantitative RT-PCR method using β-actin gene as internal control. The result showed that the expressions of LPL mRNA were detected in all examined tissues of common carp. The expression levels of LPL in the mesenteric adipose tissue was highest among these tissues, following in liver and head kidney, and the lowest expression was found in heart and white muscle.     

Cloning and characterization of a novel C-type lectin gene from shrimp Litopenaeus vannamei

In invertebrates, C-type lectins play crucial roles in innate immunity responses by mediating the recognition of host cells to pathogens and clearing microinvaders, which interact with carbohydrates and function as pattern recognition receptors (PRRs). A novel C-type lectin gene (LvLec) cDNA was cloned from hemocytes of Litopenaeus vannamei by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of LvLec was of 618 bp, consisting of a 5′-terminal untranslated region (UTR) of 60 bp and a 3′-UTR of 87 bp with a poly (A) tail. The deduced amino acid sequence of LvLec possessed all conserved features critical for the fundamental structure, such as the four cysteine residues (Cys⁵³, Cys¹²⁸, Cys¹⁴⁴, Cys¹⁵²) involved in the formation of disulfides bridges and the potential Ca²⁺/carbohydrate-binding sites. The high similarity and the close phylogenetic relationship of LvLec shared with C-type lectins from vertebrates and invertebrates. The structural features of LvLec indicated that it was an invertebrate counterpart of the C-type lectin family. The cDNA fragment encoding the mature peptide of LvLec was recombined and expressed in Escherichia coli BL21(DE3)-pLysS. The recombinant protein (rLvLec) could agglutinate bacteria E. coli JM109 depending on Ca²⁺, and the agglutination could be inhibited by mannose and EDTA. These results indicated that LvLec was a new member of C-type lectin family and involved in the immune defence response to Gram negative bacteria in Litopenaeus vannamei.     

Somatic Hybrids Between Potato and S. berthaultii Show Partial Resistance to Soil‐Borne Fungi and Potato Virus Y

Three tetraploid somatic hybrid lines produced by protoplast fusion between a dihaploid potato, Solanum tuberosum, cultivar BF15 and the wild potato species Solanum berthaultii were evaluated here for their response to different soil‐borne pathogens, that is Fusarium solani, Pythium aphanidermatum and Rhizoctonia solani as well as to infection by potato virus Y (PVY). Both hybrid and BF15 plants grown in vitro were inoculated with the tested pathogen strains, that is R. solani, P. aphanidermatum, or F. solani. The growth level and disease severity index of these plants were compared to the susceptible commercial cultivar Spunta. A better growth of inoculated hybrid plants and restricted disease symptoms were observed in comparison with the commercial plants. Under glasshouse conditions and after inoculation with R. solani and P. aphanidermatum, improved resistance of the hybrid plants to these pathogens was confirmed. Indeed, these plants showed no significant damage following inoculation and a better development in R. solani‐infected plants. The susceptibility of the hybrid tubers to R. solani, P. aphanidermatum, and to F. solani infection was also determined. A significant reduction of tissue colonisation was observed in all the hybrid lines compared to the cultivated cultivars. The STBc and STBd hybrids also showed improved resistance to the PVY ordinary strain (PVY^o) under glasshouse conditions.     

The physiological response of marine diatoms to ocean acidification: differential roles of seawater pCO2 and pH

Although increasing the pCO₂ for diatoms will presumably down‐regulate the CO₂‐concentrating mechanism (CCM) to save energy for growth, different species have been reported to respond differently to ocean acidification (OA). To better understand their growth responses to OA, we acclimated the diatoms Thalassiosira pseudonana, Phaeodactylum tricornutum, and Chaetoceros muelleri to ambient (pCO₂ 400 μatm, pH 8.1), carbonated (pCO₂ 800 μatm, pH 8.1), acidified (pCO₂ 400 μatm, pH 7.8), and OA (pCO₂ 800 μatm, pH 7.8) conditions and investigated how seawater pCO₂ and pH affect their CCMs, photosynthesis, and respiration both individually and jointly. In all three diatoms, carbonation down‐regulated the CCMs, while acidification increased both the photosynthetic carbon fixation rate and the fraction of CO₂ as the inorganic carbon source. The positive OA effect on photosynthetic carbon fixation was more pronounced in C. muelleri, which had a relatively lower photosynthetic affinity for CO₂, than in either T. pseudonana or P. tricornutum. In response to OA, T. pseudonana increased respiration for active disposal of H⁺ to maintain its intracellular pH, whereas P. tricornutum and C. muelleri retained their respiration rate but lowered the intracellular pH to maintain the cross‐membrane electrochemical gradient for H⁺ efflux. As the net result of changes in photosynthesis and respiration, growth enhancement to OA of the three diatoms followed the order of C. muelleri > P. tricornutum > T. pseudonana. This study demonstrates that elucidating the separate and joint impacts of increased pCO₂ and decreased pH aids the mechanistic understanding of OA effects on diatoms in the future, acidified oceans.     

Cloning, sequencing and expression of cDNA encoding growth hormone from Indian catfish (Heteropneustes fossilis)

A tissue-specific cDNA library was constructed using polyA⁺ RNA from pituitary glands of the Indian catfishHeteropneustes fossilis (Bloch) and a cDNA clone encoding growth hormone (GH) was isolated. Using polymerase chain reaction (PCR) primers representing the conserved regions of fish GH sequences the 3′ region of catfish GH cDNA (540 bp) was cloned by random amplification of cDNA ends and the clone was used as a probe to isolate recombinant phages carrying the full-length cDNA sequence. The full-length cDNA clone is 1132 bp in length, coding for an open reading frame (ORF) of 603 bp; the reading frame encodes a putative polypeptide of 200 amino acids including the signal sequence of 22 amino acids. The 5′ and 3′ untranslated regions of the cDNA are 58 bp and 456 bp long, respectively. The predicted amino acid sequence ofH. fossils GH shared 98% homology with other catfishes. Mature GH protein was efficiently expressed in bacterial and zebrafish systems using appropriate expression vectors. The successful expression of the cloned GH cDNA of catfish confirms the functional viability of the clone.     

Whitebark pine facilitation at treeline: potential interactions for disruption by an invasive pathogen

In stressful environments, facilitation often aids plant establishment, but invasive plant pathogens may potentially disrupt these interactions. In many treeline communities in the northern Rocky Mountains of the U.S. and Canada, Pinus albicaulis, a stress‐tolerant pine, initiates tree islands at higher frequencies than other conifers – that is, leads to leeward tree establishment more frequently. The facilitation provided by a solitary (isolated) P. albicaulis leading to tree island initiation may be important for different life‐history stages for leeward conifers, but it is not known which life‐history stages are influenced and protection provided. However, P. albicaulis mortality from the non‐native pathogen Cronartium ribicola potentially disrupts these facilitative interactions, reducing tree island initiation. In two Rocky Mountain eastern slope study areas, we experimentally examined fundamental plant–plant interactions which might facilitate tree island formation: the protection offered by P. albicaulis to leeward seed and seedling life‐history stages, and to leeward krummholz conifers. In the latter case, we simulated mortality from C. ribicola for windward P. albicaulis to determine whether loss of P. albicaulis from C. ribicola impacts leeward conifers. Relative to other common solitary conifers at treeline, solitary P. albicaulis had higher abundance. More seeds germinated in leeward rock microsites than in conifer or exposed microsites, but the odds of cotyledon seedling survival during the growing season were highest in P. albicaulis microsites. Planted seedling survival was low among all microsites examined. Simulating death of windward P. albicaulis by C. ribicola reduced shoot growth of leeward trees. Loss of P. albicaulis to exotic disease may limit facilitation interactions and conifer community development at treeline and potentially impede upward movement as climate warms.     

ZxAKT1 is essential for K+ uptake and K+/Na+ homeostasis in the succulent xerophyte Zygophyllum xanthoxylum

The inward‐rectifying K⁺ channel AKT1 constitutes an important pathway for K⁺ acquisition in plant roots. In glycophytes, excessive accumulation of Na⁺ is accompanied by K⁺ deficiency under salt stress. However, in the succulent xerophyte Zygophyllum xanthoxylum, which exhibits excellent adaptability to adverse environments, K⁺ concentration remains at a relatively constant level despite increased levels of Na⁺ under salinity and drought conditions. In this study, the contribution of ZxAKT1 to maintaining K⁺ and Na⁺ homeostasis in Z. xanthoxylum was investigated. Expression of ZxAKT1 rescued the K⁺‐uptake‐defective phenotype of yeast strain CY162, suppressed the salt‐sensitive phenotype of yeast strain G19, and complemented the low‐K⁺‐sensitive phenotype of Arabidopsis akt1 mutant, indicating that ZxAKT1 functions as an inward‐rectifying K⁺ channel. ZxAKT1 was predominantly expressed in roots, and was induced under high concentrations of either KCl or NaCl. By using RNA interference technique, we found that ZxAKT1‐silenced plants exhibited stunted growth compared to wild‐type Z. xanthoxylum. Further experiments showed that ZxAKT1‐silenced plants exhibited a significant decline in net uptake of K⁺ and Na⁺, resulting in decreased concentrations of K⁺ and Na⁺, as compared to wild‐type Z. xanthoxylum grown under 50 mm NaCl. Compared with wild‐type, the expression levels of genes encoding several transporters/channels related to K⁺/Na⁺ homeostasis, including ZxSKOR, ZxNHX, ZxSOS1 and ZxHKT1;1, were reduced in various tissues of a ZxAKT1‐silenced line. These findings suggest that ZxAKT1 not only plays a crucial role in K⁺ uptake but also functions in modulating Na⁺ uptake and transport systems in Z. xanthoxylum, thereby affecting its normal growth.     

Identification and expression profiling of Spodoptera litura OR18, a gene with a potential role in olfactory recognition

The full‐length cDNA of the gene SlituOR18, encoding a candidate olfactory receptor in the antennae of the tobacco cutworm, Spodoptera litura (Fabricius) (Lepidoptera Noctuidae), was identified through homology cloning strategies using RACE (rapid amplification of cDNA ends) and PCR (polymerase chain reaction). The protein of SlituOR18 shared >80% sequence identity and the same seven transmembrane domains with other olfactory receptor 18 (OR18) proteins sequenced from noctuid moths. SlituOR18 also had a similar structure to SlituORco, encoding the olfactory co‐receptor in S. litura. The sequence between transmembrane segments IV and V was longer than other sequences between transmembrane segments, and the N‐terminus was intracytoplasmic. Analysis by qRT‐PCR showed SlituOR18 was predominantly expressed in adult moths and there was higher expression in female antennae than in male antennae. Weak expression of SlituOR18 was observed in eggs and no expression was observed in the antennae of fourth instars and 5‐day‐old pupae. In situ hybridization experiments revealed that expression of these receptor types was clearly restricted to the bases of trichodea‐type olfactory sensilla (sensillum trichodeum), that are known to contain neurons sensitive to food odor or pheromones. Our data demonstrated that both SlituORco and SlituOR18 showed diurnal changes in their relative expression level. Expression of SlituOR18 varied among geographic populations of S. litura that had been trapped in the field using synthetic pheromone lures. The mRNA expression level of SlituOR18 was similar among S. litura populations from Sichuan, Guangxi, and Hunan, and higher than in populations from Shanghai and Ningbo. We suggest that OR18 could play a critical role in olfaction in noctuid moths and is a potential target for novel pest management strategies in the future.     

Gamma irradiation‐induced disease resistance of pear (Pyrus pyrifolia “Niitaka”) against Penicillium expansum

In this study, the effects of gamma irradiation on the resistance of pear fruit against Penicillium expansum, the causal agent of blue mould disease, were investigated. A low dose of gamma irradiation for 14 days increased the disease resistance and firmness of pear fruits. Remarkably, exposure to 200 Gy of gamma irradiation significantly maintained fruit firmness, markedly reduced disease incidence and enhanced the activity of defence‐related enzymes (e.g., β‐1,3‐glucanase, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase) and expression of pathogenesis‐related (PR) genes (e.g., PR‐1, PR‐3 and PR‐4). Therefore, the gamma irradiation‐induced resistance against P. expansum involves both metabolic changes and the induction of expression of defence‐related genes. In addition, scanning electron microscopic analysis revealed that gamma irradiation significantly inhibits the growth of P. expansum. These results suggest that exposure of mature harvested pear fruits to artificial gamma irradiation confers fungal disease resistance; therefore, gamma irradiation represents an important strategy for controlling postharvest diseases in pear fruit.     

Genetic variation in Plethodon cinereus and Plethodon hubrichti from in and around a contact zone

Climate change poses several challenges to biological communities including changes in the frequency of encounters between closely related congeners as a result of range shifts. When climate change leads to increased hybridization, hybrid dysfunction or genetic swamping may increase extinction risk—particularly in range‐restricted species with low vagility. The Peaks of Otter Salamander, Plethodon hubrichti, is a fully terrestrial woodland salamander that is restricted to ~18 km of ridgeline in the mountains of southwestern Virginia, and its range is surrounded by the abundant and widespread Eastern Red‐backed Salamander, Plethodon cinereus. In order to determine whether these two species are hybridizing and how their range limits may be shifting, we assessed variation at eight microsatellite loci and a 1,008 bp region of Cytochrome B in both species at allopatric reference sites and within a contact zone. Our results show that hybridization between P. hubrichti and P. cinereus either does not occur or is very rare. However, we find that diversity and differentiation are substantially higher in the mountaintop endemic P. hubrichti than in the widespread P. cinereus, despite similar movement ability for the two species as assessed by a homing experiment. Furthermore, estimation of divergence times between reference and contact zone populations via approximate Bayesian computation is consistent with the idea that P. cinereus has expanded into the range of P. hubrichti. Given the apparent recent colonization of the contact zone by P. cinereus, future monitoring of P. cinereus range limits should be a priority for the management of P. hubrichti populations.     

Genome‐wide association study identifies variants in the CAPN9 gene associated with umbilical hernia in pigs

Pig umbilical hernia (UH) affects pig welfare and brings considerable economic loss to the pig industry. To date, the molecular mechanisms underlying pig UH are still poorly understood. To identify potential loci for susceptibility to this disease, we performed a genome‐wide association study in an Erhualian × Shaziling F₂ intercross population. A total of 45 animals were genotyped using Illumina Porcine SNP60 BeadChips. We observed a SNP (rs80993347) located in the calpain‐9 (CAPN9) gene on Sus scrofa chromosome 14 that was significantly associated with UH (P = 1.97 × 10^?10). Then, we identified a synonymous mutation rs321865883 (g.20164T>C) in exon 10 of the CAPN9 gene that distinguished two affected individuals (CC) from their normal full‐sibs (TC). Finally, quantitative polymerase chain reaction was explored to investigate the mRNA expression profile of the CAPN9 gene in 12 tissues in Yorkshire pigs at different developmental stages (3, 90 and 180 days). CAPN9 showed high expression levels in the gastrointestinal tract at these three growth stages. The results of this study indicate that the CAPN9 gene might be implicated in UH. Further studies are required to establish a role of CAPN9 in pig UH.     

Role of ethylene and related gene expression in the interaction between strawberry plants and the plant growth‐promoting bacterium Azospirillum brasilense

• Induced systemic resistance (ISR) is one of the indirect mechanisms of growth promotion exerted by plant growth‐promoting bacteria, and can be mediated by ethylene (ET). We assessed ET production and the expression of related genes in the Azospirillum–strawberry plant interaction.
• Ethylene production was evaluated by gas chromatography in plants inoculated or not with A. brasilense REC3. Also, plants were treated with AgNO₃, an inhibitor of ET biosynthesis; with 1‐aminocyclopropane‐1‐carboxylic acid (ACC), a precursor of ET biosynthesis; and with indole acetic acid (IAA). Plant dry biomass and the growth index were determined to assess the growth‐promoting effect of A. brasilense REC3 in strawberry plants. Quantitative real time PCR (qRT‐PCR) was performed to analyse relative expression of the genes Faetr1, Faers1 and Faein4, which encode ET receptors; Factr1 and Faein2, involved in the ET signalling pathway; Faacs1 encoding ACC synthase; Faaco1 encoding ACC oxidase; and Faaux1 and Faami1 for IAA synthesis enzymes.
• Results showed that ET acts as a rapid and transient signal in the first 12 h post‐treatment. A. brasilense REC3‐inoculated plants had a significantly higher growth index compared to control plants. Modulation of the genes Faetr1, Faers1, Faein4, Factr1, Faein2 and Faaco1 indicated activation of ET synthesis and signalling pathways. The up‐regulation of Faaux1 and Faami1 involved in IAA synthesis suggested that inoculation with A. brasilense REC3 induces production of this auxin, modulating ET signalling.
• Ethylene production and up‐regulation of genes associated with ET signalling in strawberry plants inoculated with A. brasilense REC3 support the priming activation characteristic of ISR. This type of resistance and the activation of systemic acquired resistance previously observed in this interaction indicate that both are present in strawberry plants, could act synergistically and increase protection against pathogens.

     

Chemotaxonomic Considerations of the n‐Alkane Composition in Pinus heldreichii,P. nigra,and P. peuce

The n‐alkane composition in the leaf cuticular waxes of natural populations of Bosnian pine (Pinus heldreichii), Austrian pine (P. nigra), and Macedonian pine (P. peuce) was compared for the first time. The range of n‐alkanes was wider in P. nigra (C₁₆ – C₃₃) than in P. heldreichii and P. peuce (C₁₈ – C₃₃). Species also diverged in abundance and range of dominant n‐alkanes (P. heldreichii: C₂₃, C₂₇, and C₂₅; P. nigra: C₂₅, C₂₇, C₂₉, and C₂₃; P. peuce: C₂₉, C₂₅, C₂₇, and C₂₃). Multivariate statistical analyses (PCA, DA, and CA) generally pointed out separation of populations of P. nigra from populations of P. heldreichii and P. peuce (which were, to a greater or lesser extent, separated too). However, position of these species on the basis of n‐alkane composition was in accordance neither with infrageneric classification nor with recent molecular and terpene investigations.     

Hybridization,polyploidy and clonality influence geographic patterns of diversity and salt tolerance in the model halophyte seashore paspalum (Paspalum vaginatum)

In plant species, variation in levels of clonality, ploidy and interspecific hybridization can interact to influence geographic patterns of genetic diversity. These factors commonly vary in plants that specialize on saline habitats (halophytes) and may play a role in how they adapt to salinity variation across their range. One such halophyte is the turfgrass and emerging genomic model system seashore paspalum (Paspalum vaginatum Swartz). To investigate how clonal propagation, ploidy variation, and interspecific hybridization vary across ecotypes and local salinity levels in wild P. vaginatum, we employed genotyping‐by‐sequencing, cpDNA sequencing and flow cytometry in 218 accessions representing > 170 wild collections from throughout the coastal southern United States plus USDA germplasm. We found that the two morphologically distinct ecotypes of P. vaginatum differ in their adaptive strategies. The fine‐textured ecotype is diploid and appears to reproduce in the wild both sexually and by clonal propagation; in contrast, the coarse‐textured ecotype consists largely of clonally‐propagating triploid and diploid genotypes. The coarse‐textured ecotype appears to be derived from hybridization between fine‐textured P. vaginatum and an unidentified Paspalum species. These clonally propagating hybrid genotypes are more broadly distributed than clonal fine‐textured genotypes and may represent a transition to a more generalist adaptive strategy. Additionally, the triploid genotypes vary in whether they carry one or two copies of the P. vaginatum subgenome, indicating multiple evolutionary origins. This variation in subgenome composition shows associations with local ocean salinity levels across the sampled populations and may play a role in local adaptation.     

Characterization and functional analysis of hsp21.8b: An orthologous small heat shock protein gene in Tribolium castaneum

Small heat shock proteins (sHSPs) act as molecular chaperones and are widely distributed in all kinds of organisms. Comparative analysis revealed that an orthologous shsp was present during insect evolution. Here, hsp21.8b, one insect orthologous shsp, had been identified in Tribolium castaneum. Quantitative real‐time PCR illustrated that Tchsp21.8b was expressed in all developmental stages, along with the lowest expression at early embryonic stage and relative high expression at other stages especially in late eggs and late pupae. In the adult period, Tchsp21.8b exhibited the highest expression level in central nervous system and followed in elytron, epidermis, ovary and fat body. Moreover, it was upregulated 3.39‐fold in response to enhanced heat stress (45°C) for 4 hr but not to cold stress (4°C) and was upregulated by 1.73‐ to 1.94‐fold under ultraviolet (UV) exposure during 4–6 hr. It was also downregulated by 20.8%–41.8% under starvation in 3 days and had a “down‐up‐down” trend under the pathogen stresses. Larval RNA interference of Tchsp21.8b caused 40.6% insects mortality and reduced the oviposition amount by 66.0% and only 21.0% of the ds‐Tchsp21.8b eggs could hatch into larvae. These results suggested that as an orthologous shsp, Tchsp21.8b not only plays important roles in the growth, development and fecundity of T. castaneum but with the competence to resist the environment stresses, although the response is relatively weak compared to other hsps. Results from this study also uncovered the functions of the orthologous shsp in the development and anti‐stresses ability of T. castanuem. It provided more scientific evidence for revealing the physiological mechanisms of shsps of the insects and enhanced the capabilities to control different pests.     

Characterization of chitinase from Streptomyces luridiscabiei U05 and its antagonist potential against fungal plant pathogens

Streptomyces luridiscabiei U05 was isolated from wheat rhizosphere. It produced chitinase, which showed in vitro antifungal properties. The crude enzyme inhibited the growth of Alternaria alternata, Fusarium oxysporum, F. solani, Botrytis cinerea, F. culmorum and Penicillium verrucosum. The chitinase enzyme of the molecular weight of 45 kDa was purified using affinity chromatography of chitin. Streptomyces luridiscabiei U05 produced different chitinolytic enzymes. The highest enzyme activity was observed with the use of 4‐MU‐(GlcNAc)_, which points to the presence of an β‐N‐acetylhexosaminidase. The optimum activity was obtained at 35–40°C and pH 7–8. The enzyme showed thermostability at 35–40°C during 240 min of preincubation and lost its activity at 50°C and 60°C in 60 min. The chitinase activity from S. luridiscabei U05 was strongly inhibited by Hg²⁺ and Pb²⁺ ions, and sodium dodecyl sulphate (SDS). The Ca²⁺, Cu²⁺ and Mg²⁺ ions stimulated the activity of the enzyme.