Production of Angiotensin Converting Enzyme Inhibitory Peptides from Red Tilapia Protein Hydrolysates

Fish proteins are considered as valuable nutrient and a good source of many bioactive peptides such as angiotensin converting enzyme (ACE) inhibitory peptides. Very few reports are available on the ACE inhibitory peptides in freshwater fish hydrolysates. Therefore, this study was carried out with the objective to produce tilapia protein hydrolysates by commercial proteases, named Alcalase, Flavourzyme and Protamex, investigating the ACE (Angiotensin Converting Enzyme) inhibitory activity, the radical scavenging ability and identifing the best enzyme to produce the highest bioactivity; optimizing the production of ACE inhibitory peptides using response surface methodology (RSM); and to fractionate the ACE inhibitory peptides using ultrafiltration membranes. The ACE inhibitory activities were determined using an in vitro method and the IC50 (peptide concentration which reduced ACE inhibitory by 50%) was calculated. The result indicated that Alcalase was the best enzyme to produce tilapia hydrolysates since it had the highest ACE inhibitory activity when compared to Protamex and Flavourzyme. A central composite design (CCD) involving 16 cube points, 8 axial points and 7 center points was employed to study the effect of temperature, time, pH and enzyme-substrate ratio on Alcalase hydrolytic activity. The combined level of 55.8 °C, 259.99 min, pH 7.5 and enzyme-substrate ratio of 3.58 % (w/w) was predicted to provide the most desirable bioactivity, which produce high ACE inhibitory activity in tilapia hydrolysates. The coefficient of determination value (R2) was 0.883 for the experimental data, which indicated a satisfactory adjustment of the reduced response models. The time, temperature and enzyme-substrate ratio of the hydrolysis had significant (p 10 kDa, 10-5 kDa, 5-2 kDa and < 2 kDa) obtained had the ACE inhibitory activity, however, the fraction with molecular weight of < 2 kDa, appeared to have a significantly (p < 0.05) lower IC50 compared to the unfractionated hydrolysate, and the other fractio

Biochemical properties of red tilapia (Oreochromis niloticus) protein hydrolysates

The amino-acid composition, 2, 2-Diphenyl-1-picryhydrazyl (DPPH) radical-scavenging activity, and peptide patterns of tilapia protein hydrolysates produced by the enzymatic hydrolysis of Alcalase (AH), Flavourzyme (FH) and Protamex (PH) for 5h using pH-stat method were studied. The ratio of essential amino acids to non-essential amino acids increased after hydrolysis in all samples; however, no significant differences among them were observed. AH had a highest (P < 0.05) DPPH radical-scavenging activity, but no significant difference in the DPPH between FH and PH was observed. SDS-PAGE patterns for all the hydrolysates showed significant (P < 0.05) reduction in the number and the intensity of the bands with increasing time of hydrolysis. Flavourzyme showed the lowest rate of hydrolytic activity towards the tilapia mince

Pathogenesis of Dry Eye in Graft Versus Host Disease (GVHD): Role of Ocular Mucins and Conjunctival Fibrosis

Allogenic hematopoietic stem cell transplantation is a procedure that offers a possible cure for hematologic cancers and other hematologic disorders. Unfortunately, despite the increasing survival rate of patients, the quality of their life is adversely affected by the allogeneic bone marrow transplantation’s major side effect i.e Graft vs. Host Disease (GVHD). GVHD is a complex, multi-organ disease resulting from an immunological attack by donor engrafted immune cells to host organs, including the eye surface. Mostly based on the time of disease onset after transplantation, GVHD is divided into the acute and chronic phase. The eyes may be involved in both acute and chronic GVHD, although ocular involvement is more common in the chronic GVHD with a more severe presentation. As high as 40%-60% of patients with chronic GVHD suffer from debilitating ocular surface damage manifesting as severe dry eye and cicatricial conjunctivitis. Several pathological mechanisms likely contribute to the etiology of ocular GVHD-associated dry eye disease. Despite the high frequency of ocular surface involvement in patients experiencing GVHD, little is known about the underlying pathogenesis responsible for ocular GVHD-associated dry eye. In our first manuscript, using a mouse model of allogeneic transplantation, we demonstrated that ocular GVHD causes a decrease in tear film volume and corneal keratopathy. These ocular surfaces changes are accompanied by a significant decrease in the area and thickness of corneal glycocalyx, a decrease in ocular surface mucins, MUC4 and MUC5AC and loss of conjunctival goblet cells. Our data showed that topical treatment by mucin secretagogue, rebamipide, partially attenuates GVHD-associated damage to ocular surface. Hyperosmolar tears are a consistent feature of dry eye disease. Our data demonstrated that hyperosmolar stress increases the gene expression of NFAT5, a tonicity-related transcription factor and pro-inflammatory cytokines (IL1, IL6, TNFα, IFN-γ) in human corneal and conjunctival epithelial cells. Next, we demonstrated that these proinflammatory cytokines differentially modulate the expression of MUC 1, and MUC 4 in ocular surface epithelial cells, but they do not cause any notable change in glycocalyx or apoptotic cell death in stratified human corneal and conjunctival epithelial cells. Immune-mediated ocular surface damage in GVHD can initiate a wound healing response leading to fibrosis in the conjunctiva, a fibroblast-rich tissue. Conjunctival fibrosis may underlie the noted decrease in goblet cells and ocular surface mucins, thus contributing to GVHD-associated dry eye. Our results demonstrated that ocular GVHD causes a significant increase in expression of α-smooth muscle actin (SMA), a marker of myofibroblasts, in the conjunctiva. Immunostaining detected the presence of large number of myofibroblasts in bulbar orbital conjunctiva of GVHD mice. An increase in the components of renin-angiotensin system component (RAS), angiotensinogen and angiotensin converting enzyme, was also noted in the conjunctiva suggesting that ocular GVHD causes conjunctival fibrosis by myofibroblast formation and activation of conjunctival RAS

Changes in Default Mode Network as Automaticity Develops in a Categorization Task

The default mode network (DMN) is a set of brain regions in which blood oxygen level dependent (BOLD) signal is suppressed during attentional focus on the external environment. Because automatic task processing requires less attention, developmen

Design Research for Instructional Graphics: A Focus on Fall Prevention Exercises for Older Adults

Falls are a major cause of injury in old age and the leading reason for loss of independence. Regular exercise lowers the risk of falls among the elderly. The elderly display little motivation towards exercise programs. The objective of this interdisciplinary research is to explore the role that design research can play in increasing seniors’ motivation towards exercise, by creating recommendations for engaging exercise instructions. In order to investigate the role of design elements in exercise instructions, mixed research methods were utilized. The key findings of this research include, figure representations; acknowledge the benefits of exercise; and take advantage of the positive opportunities for exercising while multi-tasking. The findings resulted in design recommendations for exercise instructions that, when applied, could enhance motivation towards physical activity. Designers may use the findings from this research study as a guide for designing instructional graphics that contribute to motivating seniors in fall prevention exercise

Mathematical Modelling of Nano-Electronic Systems

Double-Qdots (DQDs) are attractive in light of their potential application to quantum computing and other electronic applications, e.g. as specialized sensors. We consider the electronic properties of a system consisting of two quantum dots in physical proximity, which we will refer to as the DQD. Our main goal is to derive the essential properties of the DQD from a model that is rigorous yet numerically tractable, and largely circumvents the complexities of an ab initio simulation. To this end we propose a class of novel Hamiltonians that captures the dynamics of a bi-partite quantum system, wherein the interaction is described via a convolution or a Wiener-Hopf type operator. We subsequently describe the density of states function and derive the electronic properties of the underlying system. Our analysis shows that the model captures a plethora of electronic profiles which serves as evidence for the versatility of the proposed framework for DQD channel modelling. A massive body of mathematical physics results, dating mostly to the last half a century, give evidence to the claim that the statistical characteristic of fluctuations in the level structure of a quantum system provides essential information about its dynamic properties, e.g. in some instances these statistical parameters show whether or not the underlying classical dynamics is integrable or chaotic. Following this tradition we have conducted statistical analysis of the data generated numerically from the model at hand. In this way we have characterized the fine-scale fluctuations of the spectra for several choices of the constituents. In conclusion, we have found that the model is versatile enough to produce several statistically distinct types of level structure. In particular, the model is capable of reproducing very complex level structures, such as those of the resonant microwave cavities that have been obtained experimentally in the 1990

Business managers’ adaption of communication and leadership characteristics amidst Covid-19: a qualitative study

The problem being studied was that because managers of for-profit businesses in California were having to communicate with their employees outside of face-to-face internal interactions (e.g., Zoom conferencing and telephone). It was unknown how business managers of for-profit businesses in California had adapted their communication and leadership styles when responding to COVID-19’s social distancing guidelines. The purpose of this qualitative descriptive study was to explore how managers of for-profit businesses in California described how their communication and leadership styles had been adapted to follow the social distancing guidelines of COVID-19. This study was guided by the communication accommodation theory and followed a qualitative descriptive system where the researcher completed semi-structured interviews with 10 participants asking them 10 open-ended questions in a private interview setting. Conducting a qualitative thematic analysis, three themes emerged from the dataset: (a) transitioning to virtual environments, (b) increased flexibility and involvement supporting virtual environments, and (c) tone, time, and lack of non-verbal cues. Limitations, implications, and recommendations for future research were also discussed

Long-Term Intravitreal Ranibizumab as a Potential Additional Risk Factor for Neurodegeneration in Parkinson's Disease: A Case Report.

In November 2012, a 72-year old patient was diagnosed with left eye wet age-related macular degeneration. The patient received three monthly intravitreal injections of ranibizumab, with complete resolution of retinal hemorrhage and edema and reinstatement of visual acuity. In May 2015, symptomatic relapse was detected. The patient was again treated with intravitreal ranibizumab, with overall six injections till the end of February 2016. In May 2016, the patient complained of left hand resting tremor, bradykinesia, and postural rigidity of head and trunk. A diagnosis of clinically established PD was made based on new criteria of the Movement Disorders Society. Single Photon Emission Computerized Tomography of the Dopamine Transporter with (123I) ioflupane documented a low Dopamine Transporter (DAT) uptake mostly in the right striatum. Due to the documented protective role of vascular endothelial growth factor (VEGF) on the dopaminergic neurons, intensive intravitreal injections of the anti-VEGF agent ranibizumab may have played as an additional risk factor accelerating the neurodegeneration process related to PD and the onset of the related clinical signs and symptoms