The Depth-Dependent Mechanical Behavior of Anisotropic Native and Cross-Linked HheG Enzyme Crystals

Enzymes are able to catalyze various specific reactions under mild conditions and can, therefore, be applied in industrial processes. To ensure process profitability, the enzymes must be reusable while ensuring their enzymatic activity. To improve the processability and immobilization of the biocatalyst, the enzymes can be, e.g., crystallized, and the resulting crystals can be cross-linked. These mechanically stable and catalytically active particles are called CLECs (cross-linked enzyme crystals). In this study, the influence of cross-linking on the mechanical and catalytic properties of the halohydrin dehalogenase (HheG) crystals was investigated using the nanoindentation technique. Considering the viscoelastic behavior of protein crystals, a mechanical investigation was performed at different indentation rates. In addition to the hardness, for the first time, depth-dependent fractions of elastic and plastic deformation energies were determined for enzyme crystals. The results showed that the hardness of HheG enzyme crystals are indentation-rate-insensitive and decrease with increases in penetration depth. Our investigation of the fraction of plastic deformation energy indicated anisotropic crystal behavior and higher irreversible deformation for prismatic crystal faces. Due to cross-linking, the fraction of elastic energy of anisotropic crystal faces increased from 8% for basal faces to 68% for prismatic crystal faces. This study demonstrates that mechanically enhanced CLECs have good catalytic activity and are, therefore, suitable for industrial use

Structure-Properties Correlation of Cross-Linked Penicillin G Acylase Crystals

In biocatalytic processes, the use of free enzymes is often limited due to the lack of long-term stability and reusability. To counteract this, enzymes can be crystallized and then immobilized, generating cross-linked enzyme crystals (CLECs). As mechanical stability and activity of CLECs are crucial, different penicillin G acylases (PGAs) from Gram-positive organisms have proven to be promising candidates for industrial production of new semisynthetic antibiotics, which can be crystallized and cross-linked to characterize the resulting CLECs regarding their mechanical and catalytic properties. The greatest hardness and Young’s modulus determined by indentation with an atomic force microscope were observed for CLECs of Bacillus species FJAT-PGA CLECs (26 MPa/1450 MPa), followed by BmPGA (Priestia megaterium PGA, 23 MPa/1170 MPa) and BtPGA CLECs (Bacillus thermotolerans PGA, 11 MPa/614 MPa). In addition, FJAT- and BtPGA CLECs showed up to 20-fold higher volumetric activities compared to BmPGA CLECs. Correlation to structural characteristics indicated that a high solvent content and low number of cross-linking residues might lead to reduced stability. Furthermore, activity seems to be restricted by small water channels due to severe diffusion limitations. To the best of our knowledge, we show for the first time in this study that the entire process chain for the characterization of diverse industrially relevant enzymes can be performed at the microliter scale to discover the most important relationships and limitation

Mantle-crust differentiation of chalcophile elements in the oceanic lithosphere

The chalcophile elements, as associated with sulfides, are believed mainly from the study of ophiolites to be generally enriched in the upper mantle, but depleted by magmatic processes in the lower and upper ocean crust. However, studies of some orogenic lherzolites suggest a copper depletion of peridotites in relation to the primitive mantle, suggesting that a portion of the sulfides is melted during decompression and incorporated into the ascending magmas. The rarity of abyssal peridotites and the high degree of their alteration have not allowed these results to be verified in situ in the oceans. Here, we present the first complete study of chalcophile elements based on a suite of rocks from an oceanic core complex (OCC), the Kane Megamullion at 22°30’N at the MidAtlantic Ridge. OCCs provide large exposures of mantle and lower crustal rocks on the seafloor on detachment fault footwalls at slow and ultraslow spreading ridges. The Kane Megamullion is one of the best sampled OCCs in the world, with 1342 rocks from 28 dredge sites and 14 dives. We have made XRF, TDMS and INAA analyses of 129 representative peridotites, gabbroic rocks, diabases and basalts. Our results suggest a depletion of some peridotites in relation to the primitive mantle (28 ppm Cu). Dunites, troctolites and olivine gabbros are relatively enriched in chalcophile elements. The amount of sulfides decreases gradually with progressive differentiation, reaching a minimum in gabbronorites and diabases. The highest bulk abundance of chalcophile elements in our sample suite was observed in dunites (up to ~ 300 ppm Cu in several samples) and a contact zone between residual peridotite and a mafic vein (294 ppm Cu). Plagioclasebearing harzburgites, generally formed by latestage melt impregnation in the mantle, are typically more enriched in Cu than unimpregnated residual peridotites. For these reasons, our initial results indicate sulfide melting during mantle melting, and their local precipitation in the mantle lithosphere due to late-stage melt impregnation

Evaluation of the occurrence of canine congenital sensorineural deafness in puppies of predisposed dog breeds using the brainstem auditory evoked response

Canine congenital sensorineural deafness (CCSD) affects predisposed breeds of dogs and is primarily caused by an atrophy of the stria vascularis of the organ of Corti. The analysis of the brainstem auditory evoked response (BAER) is a reliable method for the evaluation of hearing in animals as it allows an accurate detection of unilateral or bilateral deafness. The occurrence of unilateral and bilateral deafness using the BAER was determined in a representative group of dogs in Poland, including Bull Terriers (n = 117), Australian Cattle Dogs (n = 62), English Setters (n = 32) and the Dogo Argentino (n = 32). Overall deafness, deafness in each dog breed and an association between deafness and phenotype were studied. Among the 243 dogs tested, 156 (81%) had a normal BAER, 27 (11%) were unilaterally deaf, and 12 (5%) were bilaterally deaf. The amplitudes and latencies of waves I, II, III, V, the V/I wave amplitude ratio, and wave I–V, I–III and III–V inter-peak intervals were recorded for each dog. Unilaterally and bilaterally deaf dogs were present in all the dog breeds studied. There were 17 (14.5%) deaf Bull Terriers, three (4.8%) deaf Australian Cattle Dogs, seven (21.9%) deaf English Setters, and 12 (37.5%) deaf Dogos Argentinos. Preventive BAER screening should be routinely performed in these four breeds to prevent the spread of genes responsible for deafness

Sarcopenia as a problem of old age - a form of rehabilitation

Background: Sarkopenia as a disease has relatively recently become the object of research and the work of the academic community. Despite this, sarcopenia is an increasingly serious social problem, it can be seen in a large number of statistics and epidemiological studies. Among geriatric patients, along with their multiformity and the associated use of a large amount of medicines, it causes many negative effects related to the functioning of the whole organism as well as the quality of life of the patient himself. Material and methods: Analysis of available literature, articles in the Google Scholar and PubMed database using keywords: sarcopenia, geriatrics, rehabilitation, loss of muscle mass. Results: Among the studies and recommendations concerning sarcopenia, a continuous lack of clear, transparent and confirmed diagnostic criteria can be stated. At the diagnosis of this disease, an X-ray or a bioelectrical impedance analysis is used. Other methods used are functional tests, including a six-minute walk test or "Timed-Up and Go" test (TUG). In the case of rehabilitation of people with sarcopenia, the most effective form of kinesitherapy is individually selected resistive training, which has a positive effect not only on muscle mass growth, but also the body's protein metabolism and the improvement of the endocrine system. Physiotherapy is the most commonly used method of physical therapy, among other methods of rehabilitation there are also therapeutic massage, aqua aerobics, vibratory training, and Nordic Walking and diet supplementation. Conclusions: Sarcopenia in geriatric patients, especially with ineffective treatment and rehabilitation, has a destructive impact on both the physical and mental sphere of the patient. There is a great need for more extensive research, both on the whole disease process and the effectiveness of forms of assistance to patients

Therapeutic treatment in the elderly with heart failure

Heart failure (HF) is a clinical syndrome that is the last common stage in many cardiovascular diseases. The main causes leading to the development of HF are, among others, primary impairment of myocardial contractility, volume and / or ventricular congestion, and obstruction of the diastolic duct due to pericardial diseases. The methods of detecting heart failure include: an accurate interview with the patient, laboratory tests and echocardiography. Treatment options include non-pharmacological, pharmacological and surgical treatment. A very important aspect of cure is also physical activity and appropriate nutritional treatment

Fetal and neonatal alloimmune thrombocytopenia

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is defined as a platelet coun

A rehabilitation approach to the falls of geriatric patients

Abstract: Background: Falls of the elderly are not only in themselves one of the most common problems of geriatric patients, but also the cause of many complications that affect permanently or for a shorter period of time affect the quality of life of people over 65 years of age. These changes affect not only the efficiency and motility of the elderly but also may reduce self-esteem, limit social life or cause loss of self-confidence. Material and methods: Analysis of available literature, articles in the Google Scholar database and PubMed using keywords: falls, geriatrics, aging process, problem Results: In clinical practice, many tests and scales are used to prevent the fall of older people and related complications. These include: Timed Up & Go (TUG), Tinetti scale, Dynamic Gait Index (DGI), One Leg Standing (OLS), Four Square Step Test (FSST), Berg test or Functional Reach (FR). Preventing falls can primarily be achieved by the use of appropriate rehabilitation methods, which include, among others, kinesitherapy and properly selected orthopedic equipment. The aim of individually selected kinesitherapy is to restore or maintain the patient's full fitness through the use of physical exercises to improve the balance, increasing mobility and efficiency. In the case of orthopedic supplies, the most common are baby walkers (without wheels, walker with wheels, using a triangular and quadrangular base) and orthopedic balls. Conclusions: Prophylaxis to prevent destructive effects of falls of geriatric patients should be carried out in a comprehensive manner and cover a wide range of activities. There is a further need for research and discussion on the effectiveness of forms of rehabilitation to prevent the falls of older peopl

Laboratory tests in geriatric patients - an overview of the latest reports

Laboratory tests are extremely important in patient’s monitoring and/or diagnosing. We described those that are particularly significant for elderly patients, namely: peripheral blood morphology, arterial blood gasometry, cancer markers. The aim of this article is to summarize current knowledge about laboratory tests important in geriatrics, as well as draw attention to the diverse use of laboratory tests in clinical practise