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Objectives Platelet-rich fibrin (PRF) has been utilized in regenerative medicine as a concentration of autologous platelets and growth factors that stimulates tissue regeneration. More recently, liquid-PRF (also called injectable-PRF; i-PRF) has been brought to market utilizing PET plastic tubes. Due to new advances made in tube technology, the first aim of the present study was to investigate the liquid consistency of liquid-PRF utilizing both standard and chemically modified PET plastic tubes. Furthermore, it is well known that the conversion of PRF into a fibrin matrix is derived from the temperature-controlled enzymatic process that converts liquid fibrinogen and thrombin to solid fibrin. This study also investigated for the first time the use of a cooling device (Bio-Cool) to extend the liquid working properties of liquid-PRF. Materials and methods In total, 30 participants enrolled in this study. From each patient, four tubes of liquid-PRF were drawn, two standard white Vacuette tubes and two blue chemically modified hydrophobic tubes. Following centrifugation at 700 RCF-max for 8 min in a Bio-PRF horizontal centrifuge, one white and one blue tube were kept upright at room temperature, while the other white and blue tube were placed within the cooling device. Thereafter, the liquid-PRF layers were monitored over time until clotting occurred. Patient gender, age, and altitude above sea level (+ 5000 ft) were recorded and compared for clotting times. Results The findings from the present study demonstrated that the chemically modified PET tubes performed 37% better than the control tubes (extended the working properties of liquid-PRF by over 20 min). Most surprisingly, tubes kept in the cooling device demonstrated an average of 90 min greater working time (270% improvement). While patients living at altitude did significantly improve the clotting ability of liquid-PRF, no differences were observed when comparing male vs female or younger vs older patients in liquid-PRF clotting times. Conclusions Cooling of blood following centrifugation represented a 270% improvement in working properties of liquid-PRF. Optimization of liquid-PRF tubes utilizing chemically modified hydrophobic PET tubes also delayed the clotting process by 37%. Patient gender and age had little relevance on liquid-PRF. Clinical relevance The present findings demonstrate for the first time that cooling of liquid-PRF is able to extend the working properties of liquid-PRF by over 90 min. Thus for clinicians performing longer clinical procedures, the cooling of blood may represent a viable strategy to improve the working time of liquid-PRF in clinical practice.

Variable industrial strains have been applied in the fermentation of bulk amino acids. Strain discovery and evolution, process optimization are traditional approaches to improve the yield and efficiency of the bio-production process, hence to compete with chemical or enzymatic process in amino acids production. With the fast development of bioengineering and synthetic biology, the strains can be rationally engineered to achieve better performance and gain the capacity in the fermentation of broader range of amino acids, especially for value-added amino acids. This proposed review aims to summarize traditional and recent strains in the microbial production of amino acids, characterize their metabolic pathways and present potential objectives for rational evolution. In addition, this proposed review prospect the recent opportunities and challenges in the microbial production of value-added amino acids (rare amino acids, non-canonical amino acids, and unnatural amino acids).

Enzymatic interventions in animal skin processing are increasingly being considered as safe and benign technology options due to the reduction and replacement of potential harmful chemicals. In this study, galactosidases have been employed for rehydration of preserved skins and hides to improve the process efficiency and minimize hazardous sodium sulfide. The purpose of rehydration is to ensure the skin is hydrated uniformly to facilitate subsequent physico-chemical processes of leather making. Improper rehydration leads to reduction in the quality and value of the leather. The efficacy of the enzymatic process was studied using histological images and scanning electron microscopic analysis. Pollution load changes and the extent of carbohydrate removal were also quantified. The study indicates possibility for substantial reduction in process duration and water input (up to 30%) during rehydration of preserved animal skins when galactosidases are used as rehydration aid without affecting the quality of the leather. Thus use of galactosidases in rehydration ensures uniform accelerated rehydration and provides significant environmental benefits to tanning industry, by reducing harmful substances in subsequent operations.

Metagenomic screening of gut microbiomes led to the discovery of a new enzymatic process for the removal of group A antigens on red blood cells, providing new hope for the development of universal blood.

In this paper, laccase enzyme was immobilized onto zinc ferrite nanoparticle and the characteristics of enzyme immobilized nanoparticle (EIN) were evaluated by Fourier transform infrared (FTIR) and scanning electronic microscope (SEM). Enzymatic decolorization of dyes using EIN from single and binary systems was studied. Direct red 31 (DR31) and Acid blue 92 (AB92) were used as model dyes. The effects of several parameters such as EIN dosage, pH, and dye concentration on decolorization of dyes from single and binary systems were evaluated. The optimized amount of EIN, reaction time, and pH for decolorization of dyes from single and binary systems were 0.2 g (for DR31) and 0.3 g (for AB92), 40 min, and 3 in single systems and 0.2 g (for DR31 and AB92), 40 min, and 3 in binary systems, respectively. Dye decolorization kinetics followed Michaelis-Menten model. The results showed that enzymatic process using EIN was effective method to decolorize dyes from single and binary systems.

A combined treatment method of cutinase, keratinase, and protease was applied in the wool processing to modify the wool properties. The results demonstrated that individual protease treatment did not obviously improve the wettability and anti-felting property of wool fabrics. The combined process of cutinase and protease seemed more efficient than the keratinase-protease method, the obtained wettability and anti-felting ability of wool fabric were more encouraging. The combined use of cutinase, keratinase, and protease treatments endowed wool with more satisfactory properties compared to other methods. The contact angle of the protease-treated wool fabric reduced to 66 ° and the area shrinkage decreased to 5.2 % with an acceptable strength loss of 14 %. Reaction mechanism of the three-step enzymatic process was proposed in this paper. The data from amino acid analysis revealed the cooperative actions of cutinase, keratinase, and protease treatments during the combined enzymatic processing.

Cotton fabric samples were treated with a formulation of a total crude Trichoderma reesei cellulase in a two-step procedure. In the first step, samples were treated at a low liquor ratio by padding through the enzyme formulation at 21 degrees C and 55 degrees C with a wet pickup of 100% and batched for 12 h. The samples were then treated at a high liquor ratio (1:25) with an identical enzyme formulation at 55 degrees C, with intensive agitation. The pre-treatment influenced the overall weight loss and rate of hydrolysis in samples, and the protein concentration in the liquor of the second step. The overall weight loss was 25-28% (w/w) in the two-step procedure compared to a weight loss of 22% (w/w) in the one-step batch hydrolysis.

Three kinds of poly amino acids, poly-γ-glutamic acid, poly(ɛ-L-lysine) and multi-L-arginyl-poly (L-aspartic acid) can be synthesized by enzymatic process independently from ribosomal protein biosynthesis pathways in microorganism. These biosynthesized polymers have attracted more and more attentions because of their unique properties and various applications. In this review, the current knowledge on the biosynthesis, biodegradations and applications of these three poly amino acids are summarized.

A novel enzymatic process for the synthesis of chiral pantothenonitrile through the asymmetric reduction of 2′-ketopantothenonitrile is described.Sporidiobolus salmonicolor AKU 4440 was found to convert 2′-ketopantothenonitrile (50 mg/ml) to D-(+)-pantothenonitrile (93.6% e.e.), with a molar yield of 95.6%. In a similar manner, conversion to L-(−)-pantothenonitrile occurred on incubation with washed cells ofRhodotorula glutinis AKU 4845 as the catalyst.

Enzymatic cyclization of the linear polyketide chain to form a macrolactone is a key step in the biosynthesis of type I polyketide natural products. Structural biology and inhibitor design were used to gain insight into the mechanism and specificity of this enzymatic process.

Routine expression analysis of complete mammalian genomes will require the extension of several existing technologies. Spotters will need to be able to print features more densely, and the cost and labor involved in preparing probe DNA for slide manufacture needs to be reduced. To meet these goals, we employ non-contact piezoelectric ink-jet print heads. These print heads can produce features as small as 50 microns, and we routinely spot samples at densities allowing 100,000 features per slide. With 75 micron center-to-center spacing, one would be able to spot 200,000 features per slide. Another advantage of ink-jet print heads is that features can be printed without stopping spotter movement, and can therefore achieve printing speeds of 20 spots per second per printing head. DNA preparation by conventional PCR is labor intensive, time consuming and expensive. One hundred thousand PCR reactions require greater than 1,000 96-well plates, and 100 microliter reactions use nearly $1 worth of enzyme per reaction. This will prohibit many labs from routinely manufacturing complete mammalian chips. We have developed a surface attachment chemistry that allows the probe DNA to be amplified directly on the slide in a single enzymatic process, making the cost and time required to prepare a slide only a few times greater than a single reaction. Using this chemistry, the probes are attached at their 5' ends to an acrylamide matrix. This approach has two theoretical advantages. First, probe molecules are attached to a volume of acrylamide rather than a two-dimensional surface, which enables a greater amount of probe to be attached per feature. In principle, this could increase the signal-to-noise ratio of hybridization reactions. Second, a 5' attachment increases the kinetics of target-probe hybridization, and may increase the specificity of hybridization compared with probes attached to the surface at many bases by UV crosslinking. We believe this will allow more stringent wash conditions, and may enhance the specificity of hybridization reactions.

Acetone preparation of mycobacteria B5 possesses a monoaminoxidase activity (substrate — thyamine). The greatest activity of the enzyme is manifested when the pH of the medium is 8–10. At 37°C and the optimal pH of the medium, of the substrate concentration, and of the acetone B5 mycobacteria preparation the enzymatic process becomes balanced in 16–20 h. Monoaminoxidase of B5 bacteria is a thermolabile enzyme: suspension of the acetone bacterial preparation completely loses the monoaminoxidase activity following heating for 5 min at 65°C. β-phenylisopropylhydrazine and ipraside (1-isonicotinoyl-E-isopropylhydrazine) depress the monoaminoxidase activity of mycobactena B5 β-phenylisopropylhydrazine is a stronger enzyme inhibitor than ipraside. Monoaminoxidase of mycobacteria B5 is similar to the monoaminoxidase of the animal origin by its properties.

THE mechanisms by which airborne molecules stimulate the olfactory receptors of insects remain largely undefined. In the Insecta, antennal sensilla contain pores which connect the external environment with the receptor membrane of the dendritic nerve endings1–3. The ultimate fate of the stimulant molecule that enters the pore is not yet known. Unpublished data cited by Schneider1 and Kaissling4 indicated that bombykol (E)-10, (Z)-12-hexadecadien-1-ol, was progressively metabolized into acid and ester after absorption on the antennae, or other body parts of males and females of Bombyx mori (L.). This finding cannot be directly correlated with any specific step in the olfactory mechanism, but it suggested that an enzymatic process might be involved at some point. Other indications of chemical stimulants interacting with protein substances in the antennae of insects have been reported5,6.

SOME years ago, I was able to demonstrate that œstrone which had been administered to the organism very soon became inactive1. Mature mice or infantile rats were injected subcutaneously with large doses of œstrone (up to 40,000 M.U.). Three to seventy-two hours after the administration of the hormone the animals were killed, cut into small pieces and extracted in toto with an organic solvent. It was apparent that even after a very short time, only very insignificant amounts of the hormone (about 1 per cent) could be detected. There remained, indeed, always a certain quantity of active hormone, sufficient to produce œstrus; but the question whether we were considering a hormone which had not become inactive, or one which had become reactivated again, could not be decided. œstrone is inactivated in the liver, probably by means of an enzymatic process. This inactivation, apparently, is a general biological reaction, since it takes place not only in warm-blooded, but also in cold-blooded animals and in plants as well.

As appears from recent publications of Indian workers (Sreenivasaya and Bhagvat1, compare also Rona and Fischgold2), a considerable volume change is observed in systems in which enzymatic cleavages take place. This volume change may be applied to the estimation of enzyme activity, and the dilatometric methods thus developed possess certain advantages, among which may be mentioned the continuous observation of the undisturbed enzymatic process. While looking around for possible means of refining the histochemical methods previously de-scribed (Linderstrom-Lang and Holter3), I came across the falling drop method for the measurement of specific gravity (Barbour and Hamilton4), a method which recently was re-investigated and improved by Fenger-Eriksen, Krogh and Ussing5. Experience with this method led to the development of a static principle of measurement especially suited for estimation of volume changes in small drops and therefore for micro-estimation of enzyme activity. The following description is concerned only with the application of the method for this latter purpose, but the method may prove useful for the estimation of specific gravity also in other cases.

In vitro degradation of TRH by human plasma has been demonstrated in adults. This study concerns plasma TRH-DA during the neonatal period.(H3)TRH is incubated in 50ul of plasma, extracted and intact (H3)TRH quantitated by high pressure liquid chromatography after one hour incubation period.(H3)TRH after 0 minute incubation is the reference value and results are expressed in % TRH remaining after one hour.Paired mother and newborn (arterial cord plasma) n=7 and neonates from day 1 to 5 (n=5 each day) are studied. Maternal values TRH-DA are not significantly different from adult euthyroid control (37.5±5). Plasma of neonate have a very low TRH-DA.Activity appears at day 3 and reachs maternal values at day 5. The known increase of plasma T3 level in newborn occurs 2 days before appearance of any degrading activity. In conclusion - Plasma of newborns have no TRH-DA until day 3. This metabolic immaturity may play a role in the neonatal thyroid hyperactivity. T3 induction of this enzymatic process demonstrated in rats as to be considered in human.