Periosteal Flaps Enhance Prefabricated Engineered Bone Reparative Potential.

The clinical translation of bone tissue engineering for reconstructing large bone defects has not advanced without hurdles. The in vivo bioreactor (IVB) concept may therefore bridge between bone tissue engineering and reconstructive surgery by employing the patient body for prefabricating new prevascularized tissues. Ideally, IVB should minimize the need for exogenous growth factors/cells. Periosteal tissues are promising for IVB approaches to prefabricate tissue-engineered bone (TEB) flaps. However, the significance of preserving the periosteal vascular supply has not been adequately investigated. This study assessed muscle IVB with and without periosteal/pericranial grafts and flaps for prefabricating TEB flaps to reconstruct mandibular defects in sheep. The sheep (n = 14) were allocated into 4 groups: muscle IVB (M group; nM = 3), muscle + periosteal graft (MP group; nMP = 4), muscle + periosteal flap (MVP group; nMVP = 4), and control group (nControl = 3). In the first surgery, alloplastic bone blocks were implanted in the brachiocephalic muscle (M) with a periosteal graft (MP) or with a vascularized periosteal flap (MVP). After 9 wk, the prefabricated TEB flaps were transplanted to reconstruct a mandibular angle defect. In the control group, the defects were reconstructed by non-prevascularized bone blocks. Computed tomography (CT) scans were performed after 13 wk and after 23 wk at termination, followed by micro-CT (µCT) and histological analyses. Both CT and µCT analysis revealed enhanced new bone formation and decreased residual biomaterial volume in the MVP group compared with control and MP groups, while the M group showed less new bone formation and more residual biomaterial. The histological analysis showed that most of the newly formed bone emerged from defect edges, but larger areas of new bone islands were found in MP and MVP groups. The MVP group showed enhanced vascularization and higher biomaterial remodeling rates. The periosteal flaps boosted the reconstructive potential of the prefabricated TEB flaps. The regenerative potential of the periosteum was manifested after the transplantation into the mechanically stimulated bony defect microenvironment.

Cardiopulmonary effects of vatinoxan in sevoflurane-anaesthetised sheep receiving dexmedetomidine.

The effects of pre-treatment with vatinoxan (MK-467) on dexmedetomidine-induced cardiopulmonary alterations were investigated in sheep. In a crossover study design with a 20-day washout, seven sheep were anaesthetised with sevoflurane in oxygen and air. The sheep were ventilated with the pressure-limited volume-controlled mode and a positive end-expiratory pressure of 5cmH2O. Peak inspiratory pressure (PIP) was set at 25cmH2O. The sheep received either 150µg/kg vatinoxan HCl (VAT+DEX) or saline intravenously (IV) 10min before IV dexmedetomidine HCl (3µg/kg, DEX). Cardiopulmonary variables were measured before treatments (baseline), 3min after vatinoxan or saline, and 5, 15 and 25min after dexmedetomidine. Computed tomography (CT) of lung parenchyma was performed at baseline, 2min before dexmedetomidine, and 10, 20 and 30min after DEX. Bronchoalveolar lavage (BAL) was performed after the last CT scan and shortly before sheep recovered from anaesthesia. After VAT, cardiac output significantly increased from baseline. DEX alone significantly decreased partial arterial oxygen tension, total dynamic compliance and tidal volume, whereas PIP was significantly increased. With VAT+DEX, these changes were minimal. No significant changes were detected in haemodynamics from baseline after DEX. With VAT+DEX, mean arterial pressure and systemic vascular resistance were significantly decreased from baseline, although hypotension was not detected. On CT, lung density was significantly increased with DEX as compared to baseline. No visual abnormalities were detected in bronchoscopy and no differences were detected in the BAL fluid after either treatment. The pre-administration of vatinoxan alleviates dexmedetomidine-induced bronchoconstriction, oedema and hypoxaemia in sevoflurane-anaesthetised sheep.

Syringomyelia and Craniocervical Junction Abnormalities in Chihuahuas.

BACKGROUND: Chiari-like malformation (CM) and syringomyelia (SM) are widely reported in Cavalier King Charles Spaniels and Griffon Bruxellois dogs. Increasing evidence indicates that CM and SM also occur in other small and toy breed dogs, such as Chihuahuas. OBJECTIVES: To describe the presence of SM and craniocervical junction (CCJ) abnormalities in Chihuahuas and to evaluate the possible association of CCJ abnormalities with SM. To describe CM/SM-related clinical signs and neurologic deficits and to investigate the association of CM/SM-related clinical signs with signalment, SM, or CCJ abnormalities. ANIMALS: Fifty-three client-owned Chihuahuas. METHODS: Prospective study. Questionnaire analyses and physical and neurologic examinations were obtained before magnetic resonance and computed tomography imaging. Images were evaluated for the presence of SM, CM, and atlantooccipital overlapping. Additionally, medullary kinking, dorsal spinal cord compression, and their sum indices were calculated. RESULTS: Scratching was the most common CM/SM-related clinical sign and decreased postural reaction the most common neurologic deficit in 73 and 87% of dogs, respectively. Chiari-like malformation and SM were present in 100 and 38% of dogs, respectively. Syringomyelia was associated with the presence of CM/SM-related clinical signs (P = 0.034), and medullary kinking and sum indices were higher in dogs with clinical signs (P = 0.016 and P = 0.007, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE: Syringomyelia and CCJ abnormalities are prevalent in Chihuahuas. Syringomyelia was an important factor for the presence of CM/SM-related clinical signs, but many dogs suffered from similar clinical signs without being affected by SM, highlighting the clinical importance of CCJ abnormalities in Chihuahuas.

The Utility of Acute-Phase Proteins in the Assessment of Treatment Response in Dogs With Bacterial Pneumonia.

BACKGROUND: Acute-phase proteins (APPs) are sensitive markers of inflammation, and serum C-reactive protein (CRP) recently has been shown to be a useful diagnostic marker in dogs with bacterial pneumonia (BP). In humans with community-acquired pneumonia, APPs also have great utility as follow-up markers aiding in the assessment of treatment response. OBJECTIVES: The aim of our study was to investigate the applicability of APPs as markers of treatment response in dogs with BP. ANIMALS: Nineteen dogs diagnosed with BP and 64 healthy dogs. METHODS: The study was conducted as a prospective longitudinal observational study. Serum CRP, serum amyloid A (SAA), and haptoglobin concentrations were followed during a natural course of BP. Normalization of serum CRP was used to guide the duration of antibiotic treatment (treatment was stopped 5-7 days after CRP normalized) in 8 of 17 dogs surviving to discharge; 9 of 17 dogs were treated according to conventional recommendations. RESULTS: All measured APPs initially were significantly increased, but the magnitude of increase was not correlated to disease severity. C-reactive protein and SAA concentrations decreased rapidly after initiation of antimicrobial treatment. When normalization of serum CRP was used to guide the duration of antibiotic treatment, treatment duration was significantly (P = .015) decreased without increasing the number of relapses. CONCLUSIONS AND CLINICAL IMPORTANCE: Serum CRP and SAA reflected the recovery process well and therefore may be used as markers of treatment response. According to the results, the normalization of serum CRP may be used to guide the duration of antibiotic treatment in dogs with BP.

Radiographic evaluation of elbow incongruity in Skye terriers.

OBJECTIVES: Aims of this study were to radiographically evaluate elbow congruity and to explore associations between elbow incongruity and lameness in Skye terriers. METHODS: Mediolateral, 90°-flexed, elbow joint radiographs were obtained for 45 Skye terriers. Elbow joint incongruity was graded mild, moderate or severe by measuring the width of the humeroulnar joint space. A questionnaire provided information on lameness history for each dog. RESULTS: In total, 49% (22/45) of the dogs had moderate or severe elbow joint incongruity which associated with lameness. Owner-reported lameness was common: 15/45 (33%) dogs had been lame when less than one year old, and 6 (14%) had been lame at an older age. All dogs presenting with lameness when older than one year had also been lame in adolescence. CLINICAL SIGNIFICANCE: Lameness and moderate-to-severe elbow joint incongruity were common in Skye terriers and the two were associated. A novel protocol for radiographic screening of elbow joint incongruity of chondrodystrophic breeds is suggested.

Co-infections with respiratory viruses in dogs with bacterial pneumonia.

BACKGROUND: Bacterial pneumonia (BP) is an inflammation of the lower airways and lung parenchyma secondary to bacterial infection. The pathogenesis of BP in dogs is complex and the role of canine respiratory viruses has not been fully evaluated. OBJECTIVES: The aim of this study was to investigate the occurrence of viral co-infections in dogs with BP and to assess demographic or clinical variables as well as disease severity associated with viral co-infections. ANIMALS: Twenty household dogs with BP caused by opportunistic bacteria and 13 dogs with chronic (>30 days) tracheobronchitis caused by Bordetella bronchiseptica (BBTB). METHODS: Prospective cross-sectional observational study. Diagnosis was confirmed by clinical and laboratory findings, diagnostic imaging, and cytologic and microbiologic analysis of bronchoalveolar lavage or transtracheal wash fluid. Canine parainfluenza virus (CPIV), canine adenovirus, canine herpes virus, canine influenzavirus, canine distemper virus, canine respiratory coronavirus (CRCoV) and canine pneumovirus, as well as B. bronchiseptica and Mycoplasma spp. were analyzed in respiratory samples using PCR assays. RESULTS: CPIV was detected in 7/20 and CRCoV in 1/20 dogs with BP. Respiratory viruses were not detected in dogs with BBTB. There were no significant differences in clinical variables between BP dogs with and without a viral co-infection. CONCLUSION AND CLINICAL IMPORTANCE: Respiratory viruses were found frequently in dogs with BP and may therefore play an important role in the etiology and pathogenesis of BP. Clinical variables and disease severity did not differ between BP dogs with and without viral co-infection.

Long-term outcome and use of 6-minute walk test in West Highland White Terriers with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an incurable interstitial lung disease occurring mainly in West Highland White Terriers (WHWTs). The effects of IPF on survival and on exercise tolerance in WHWTs are unknown. OBJECTIVES: To evaluate survival, prognostic factors, and exercise tolerance in WHWTs with IPF. ANIMALS: Privately owned WHWTs; 15 with IPF and 11 healthy controls. METHODS: Prospective case-control study conducted in 2007-2012. For survival, descriptive statistics and Kaplan-Meier (KM) survival curves with Cox proportional hazard ratios were performed. For the prognostic factor study, KM curves, Cox regression analysis, and logistic regression models were used. The 6-minute walk test (6MWT) was used for measurement of exercise tolerance. RESULTS: The median IPF-specific survival of deceased WHWTs (7/15) with IPF was 32 (range 2-51) months from onset of clinical signs. The risk of death from birth in WHWTs with IPF in age-adjusted Cox model was significantly higher (hazard ratio 4.6; 95% confidence interval 1.05-19.74, P = .04) than in control WHWTs. No significant prognostic factors were identified. In 6MWT, WHWTs with IPF walked a shorter distance, median 398 m (range 273-519 m), than healthy controls, median 492 m (420-568 m), P = .05, and the partial pressure of oxygen in arterial blood in diseased dogs had a moderate positive correlation with walking distance (Kendall's tau-b = 0.69, P = .06). CONCLUSION AND CLINICAL IMPORTANCE: IPF had a negative impact on life expectancy, but individual survival varied considerably. 6MWT proved to be a well-tolerated, noninvasive test to evaluate exercise tolerance.

Evaluation of accuracy of the Finnish elbow dysplasia screening protocol in Labrador retrievers.

OBJECTIVE: To determine whether the current Finnish screening method using a single flexed mediolateral view as scored by osteophyte is sufficient to diagnose mild elbow dysplasia in Labrador retrievers and to determine if an additional craniocaudal oblique projection would result in improvement in the screening protocol. MATERIALS AND METHODS: Thirteen dogs with one mildly affected elbow joint and one elbow joint without radiological evidence of osteophytes were studied. Radiographic and computed tomography studies were performed and the results compared with each other. RESULTS: Medial compartment disease was observed in 14 of 26 joints based on computed tomography. The sensitivity and specificity of the grading based mainly on osteoarthritis was 79 and 92%, respectively. A strong association existed between elbow dysplasia based on computed tomography and medial humeral epicondylar osteophytes on the craniocaudal projection. CLINICAL SIGNIFICANCE: A single mediolateral flexed radiograph is reliable in diagnosing mild elbow dysplasia in Labrador retrievers. However, the craniocaudal oblique projection increases the specificity of the diagnosis, and it is proposed that it be included in the radiographic protocol in this breed.

Dermoid sinus and spina bifida in three dogs and a cat.

This case series describes four cases of concomitant dermoid sinus and spina bifida in a Chinese crested dog, two Swedish vallhunds and a Burmese cat. The diagnosis was confirmed by computed tomography, computed tomography fistulography and pathology. Two dogs that showed abnormalities during neurological examination underwent magnetic resonance imaging. One of them had imaging findings interpreted as syringohydromyelia. All the dogs underwent surgery and the outcome was considered good in all the cases. Based on clinical and pathological examination as well as diagnostic imaging findings, two of the dermoid sinuses were classified as type IV, and two of them showed a previously unreported type of dermoid sinus. This new type is suggested here as type VI.

Clinical, bronchoscopic, histopathologic, diagnostic imaging, and arterial oxygenation findings in West Highland White Terriers with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic, interstitial lung disease primarily affecting West Highland White Terriers (WHWTs). OBJECTIVE: To describe the clinicopathological and diagnostic imaging features in WHWTs with IPF. ANIMALS: Twelve WHWTs with IPF and 14 healthy control WHWTs. METHOD: Prospective study. Clinical signs and findings of physical examination, blood and arterial blood gas analyses, radiography, high-resolution computed tomography (HRCT), bronchoscopy and bronchoalveolar lavage (BAL) of IPF dogs were obtained and compared with controls. Histopathologic changes in IPF dogs were evaluated. RESULTS: Mean partial pressure of oxygen was significantly lower in IPF (mean ± SD, 65.5 ± 15.4 mmHg) than in controls (99.1 ± 7.8 mmHg, P<.001). The alveolar-arterial oxygen gradient was significantly higher in IPF (50.1 ± 17.3 mmHg) than in controls (17.5 ± 4.9 mmHg, P<.001). In HRCT, ground glass opacity (GGO) was detected in all IPF dogs, traction bronchiectasis in 4, and honeycombing in 1. Bronchoscopic airway changes were noted in all IPF dogs. On BAL fluid (BALF) cytology, the total cell count (TCC) was higher in IPF dogs, and the numbers but not the percentages of macrophages, neutrophils, and mast cells were increased. On histopathology, multifocal or diffuse interstitial fibrosis, type II pneumocyte hyperplasia, prominent intraalveolar macrophages, distortion of alveolar architecture, and emphysematous change were detected. CONCLUSION AND CLINICAL IMPORTANCE: IPF causes substantial hypoxemia. In HRCT, GGO is a consistent finding. IPF dogs have concurrent airway changes and an increase in BALF TCC.

Quantitative magnetic resonance imaging of experimentally injured porcine intervertebral disc.

BACKGROUND: Changes in T2 relaxation time (T2-TR) and apparent diffusion coefficients (ADC) have been suggested to appear in the intervertebral disc before morphological changes. Such sensitive imaging methods could be beneficial in the targeting and follow-up of intradiscal gene therapy. PURPOSE: To investigate the sensitivity of quantitative magnetic resonance (MR) imaging methods (T2-TR and ADC) in early disc degeneration, using an experimental porcine intervertebral disc injury model, and to investigate their sensitivity in depicting biochemically controlled degenerative changes in the disc. MATERIAL AND METHODS: Six juvenile pigs underwent experimental annular stab incisions, one superficial and one reaching the nucleus pulposus. The animals underwent repeated 1.5T MR imaging and were sacrificed 4 or 8 weeks after operation. Presence of degenerative changes was controlled with biochemical analysis. RESULTS: Discs with full-thickness annular incisions lost 30% of their sagittal mid-slice nucleus pulposus area in 2 weeks (P<0.05). T2-TRs of the respective discs were on average 73% of the control discs (P<0.05). Discs with full-thickness annular lesions showed increased ADC values 4 weeks and reduced ADC values 8 weeks after the operation, compared to control discs (P<0.05). Biochemical analysis showed changes consistent with early degeneration. CONCLUSION: Early traumatic or degenerative changes are detectable with both T2-TR and ADC. The ADC in the early phase after experimental trauma seems to initially increase before decreasing.

Calcification of the intervertebral discs and curvature of the radius and ulna: a radiographic survey of Finnish miniature dachshunds.

The vertebral column of 124 randomly selected miniature dachshunds, representing 4.5% of the population registered by the Finnish Kennel Club during the years 1988 to 1996, were radiographed. The front legs were also radiographed in order to evaluate the curvature of the radius and ulna. Calcified discs were found in 75.9% of the longhaired miniature dachshunds and in 86.7% of the wirehaired ones. The occurrence of signs associated with IDD was 16.5% in longhaired and 15.6% in wirehaired miniature dachshunds. The occurrence of signs of IDD in dogs with calcified discs was 20.0% and 17.9% in longhaired and wirehaired miniature dachshunds, respectively. In dogs without calcifications only one dog showed signs of IDD. The curvature of the radius and the ulna did not differ between the dogs with signs of IDD and the healthy ones, or between the dogs with and without intervertebral calcifications. Our results indicate that radiographic eradication based on the presence of intervertebral calcifications is not suitable for breeding purposes for the Finnish miniature dachshund population because the percentage of dogs without calcifications is small.

In vivo detection of intervertebral disk injury using a radiolabeled monoclonal antibody against keratan sulfate.

UNLABELLED: In the intervertebral disk, proteoglycans form the major part of the extracellular matrix, surrounding chondrocytelike disk cells. Keratan sulfate is a major constituent of proteoglycans. METHODS: We have radioiodinated a monoclonal antibody raised against keratan sulfate. This antibody was injected into rats (n = 6), and the biodistribution was studied. A model of intervertebral disk injury was developed, and two tail disks in each animal with both acute (2 wk old) and subacute (7 wk old) injuries were studied for in vivo antibody uptake. RESULTS: The biodistribution at 72 h was as follows: blood, 0.0018 percentage injected dose per gram of tissue (%ID/g); lung, 0.0106 %ID/g; esophagus, 0.0078 %ID/g; kidney, 0.0063 %ID/g; liver, 0.0047 %ID/g; spleen, 0.0046 %ID/g; heart, 0.0036 %ID/g; thyroid, 0.0034 %ID/g; muscle, 0.0017 %ID/g; and bone, 0.0016 %ID/g. In the subacute stage, a significant difference (P < 0.006) was found in antibody uptake between injured disks (n = 12) and adjacent healthy disks (n = 12). In vivo gamma imaging showed increased uptake in other animals having lumbar disk injuries (2, 7, and 17 d after injury). Cartilage tissue, such as the trachea, was studied separately and showed extremely high antibody uptake, 0.10 %ID/g. Rat trachea was also visualized on gamma images. CONCLUSION: Our data suggest that antibodies against nucleus pulposus components, such as proteoglycans, can be used for in vivo detection of intervertebral disk injury. This finding is in spite of the minimal circulation present in intervertebral disks.

Endoxylanase II from Trichoderma reesei has several isoforms with different isoelectric points.

Two minor xylanases present in Trichoderma reesei Rut C30 cultivation broth were purified as a mixture using ion-exchange, hydrophobic-interaction and gel chromatography. The purified enzyme preparation contained two active xylanases with pI values of 7.1 and 8.1. Both components had a molecular mass of 20 kDa. The purified xylanase preparation exhibited properties very similar to those of the previously isolated XYL II (pI 9.0) of T. reesei Rut C30. The activity and stability properties, apparent kinetic parameters as well as the titration curve forms were similar. The major difference in enzymic properties was the significantly lower specific activity of the pI-7.1+8.1 xylanase mixture (3350 nkat/mg) compared with the specific activity of XYL II (13500 nkat/mg). Amino acid sequences of tryptic peptides (34% of the total amino acid sequence was determined) were identical to the amino acid sequence of XYL II. Furthermore, in vitro modification of the pI-9.0 form of XYL II to pI-8.1 and pI-7.1 forms was demonstrated. Thus the purified xylanase preparation most probably contained two modified forms of XYL II. The primary amino acid sequence of XYL II contains 28 glutamine and asparagine residues and theoretically deamination of one of them lowers the pI to 8.06 and deamination of two amino acids lowers the pI to 7.02.

Immunoaffinity Chromatographic Purification of Cellobiohydrolase II Mutants from Recombinant Trichoderma reesei Strains Devoid of Major Endoglucanase Genes

Efficient purification of Trichoderma reesei cellobiohydrolase II (CBHII) requires the use of affinity chromatography based on a substrate analogue. Due to altered substrate binding, the purification of many active-site mutants of CBHII from the complex fungal culture media represents a considerable challenge. Here we describe a combination of two approaches to facilitate the purification: the first is based on the construction of novel engineered T. reesei strains devoid of the major contaminating endoglucanases, and the second uses immunoaffinity chromatography as the final purification step. Two different procedures for the preparation of the antibody matrix were tested. Crosslinking of the monoclonal antibody to Protein G matrix instead of the conventional immobilization via cyanogen bromide increased the binding efficiency. Three different active-site mutants of CBHII bound to the immunoaffinity column in neutral pH and were eluted in pH 2.7. The purity of the CBHII mutant preparations was tested using small chromophoric substrates and hydroxyethyl cellulose, which are hydrolyzed by many other cellulases but not by CBHII. The immunoaffinity column purified the CBHII mutants over 800-fold in a single step and resulted in homogeneous protein preparations free of proteolytically cleaved forms of CBHII. The use of the double replacement T. reesei production strains, especially the one lacking the genes coding for both the endogeneous CBHII and the endoglucanase II (EGII), helped to reduce the total endoglucanase activity in the preparations.

Immunoaffinity chromatographic purification of cellobiohydrolase II mutants from recombinant trichoderma reesei strains devoid of major endoglucanase genes.

Efficient purification of Trichoderma reesei cellobiohydrolase II (CBHII) requires the use of affinity chromatography based on a substrate analogue. Due to altered substrate binding, the purification of many active-site mutants of CBHII from the complex fungal culture media represents a considerable challenge. Here we describe a combination of two approaches to facilitate the purification: the first is based on the construction of novel engineered T. reesei strains devoid of the major contaminating endoglucanases, and the second uses immunoaffinity chromatography as the final purification step. Two different procedures for the preparation of the antibody matrix were tested. Crosslinking of the monoclonal antibody to Protein G matrix instead of the conventional immobilization via cyanogen bromide increased the binding efficiency. Three different active-site mutants of CBHII bound to the immunoaffinity column in neutral pH and were eluted in pH 2.7. The purity of the CBHII mutant preparations was tested using small chromophoric substrates and hydroxyethyl cellulose, which are hydrolyzed by many other cellulases but not by CBHII. The immunoaffinity column purified the CBHII mutants over 800-fold in a single step and resulted in homogeneous protein preparations free of proteolytically cleaved forms of CBHII. The use of the double replacement T. reesei production strains, especially the one lacking the genes coding for both the endogeneous CBHII and the endoglucanase II (EGII), helped to reduce the total endoglucanase activity in the preparations.

Reproductive status, blood chemistry, gill histology and growth of perch (Perca fluviatilis) in three acidic lakes.

Perch (Perca fluviatilis L.) were sampled soon after spawning in three small acidic lakes (pH 4.3-6.1, Al(lab) 5-106 microg litre(-1), Ca2+ 0.01-0.08 mmol litre(-1)) and in one circumneutral lake (pH 5.9-6.4, Al(lab) 4-12 microg litre(-1), Ca2+ 0.06-0.07 mmol litre(-1)) in southern Finland. Due to the delayed spawning of perch in the acidic lakes, sampling in those lakes was performed later than in the reference lake. In spite of that, the gonadosomatic index (GSI) of males in all the acidic lakes was significantly greater than in the reference lake. Of the two lakes with similar low water pH, the effects on reproduction were more prominent in the lake with higher water Al content. The plasma Ca2+ concentrations of females in the acidic lakes were significantly smaller than in the females of the reference lake. The low female:male plasma Ca2+ ratio (1.0-1.32) depicted delay of spawning. Stress in perch in acidic water was also seen in elevated blood haematocrit values, especially in females. On the other hand, a low plasma Cl- level, a common response to acidic water in salmonids, was not detected in perch in the most acidic lakes. The amount of Al accumulated in the gill epithelium was highest in the most acidified lake with high Al concentration, but was also pronounced in a lake with low pH and low Al concentration.

A new appraisal of the endoglucanases of the fungus Trichoderma reesei.

The properties and enzymic activity of endoglucanases (EC 3.2.1.4) of the fungus Trichoderma reesei were studied by means of immunological methods and by using polyglycosidic substrates. Endoglucanases exist in the culture liquid as a series of immunologically related components. The most active endoglucanase component has an Mr of 43 000 and pI value of 4.0. The most abundant components have a value of pI about 5.0, an Mr of 56 000-67 000 and specific activity only one-fifth of that of the pI-4.0 component. During purification and storage the endoglucanases are spontaneously modified; the relative proportion of components having greater Mr values, more alkaline pI values and lower specific activities is increased. The hexose content of the endoglucanase components is 2-7%. Endoglucanases hydrolyse soluble beta-1,4 glycans. The enzymes described here differ from endoglucanase preparations described previously in not showing activity towards insoluble substrates. The role of endoglucanases in wood hydrolysis is consequently limited to the stage where wood constituents are already in soluble form.

Combination of three techniques for the study of complex enzyme mixtures: polyacrylamide gel electrophoresis, immunodiffusion and detection of enzymatic activity.

A technique is presented in which two different separation methods are combined. The first separation is carried out in polyacrylamide gel electrophoresis, which is then followed by immunodiffusion in agarose against appropriate antisera. Soluble and insoluble macromolecular carbohydrates were used as substrates in the detection of the various enzymatic activities. These three methods in combination can provide new information on enzymatically active proteins in mixtures, such as isoenzymes, and multiple forms varying in molecular size.

Cellobiohydrolase from Trichoderma reesei.

A 1,4-beta-D-glucan cellobiohydrolase (EC 3.2.1.91) was purified from the culture liquid of Trichoderma reesei by using biospecific sorption on amorphous cellulose and immunoaffinity chromatography. A single protein band in polyacrylamide-gel electrophoresis and one arc in immunoelectrophoresis corresponded to the enzyme activity. The Mr was 65 000. The pI was 4.2-3.6. The purified enzyme contained about 10% hexose. The enzyme differs from previously described cellobiohydrolases in being more effective in the hydrolysis of cellulose.