Biology and Biotechnology

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1,25-Dihydroxyvitamin D3 effects on the regulation of the insulin receptor gene in the hind limb muscle and heart of streptozotocin-induced diabetic rats
(Scientific Research Publishing, 2013-04) Calle, Consuelo; Maestro, Begoña; García-Arencibia, Moisés
In the present study, we examine the effects of the treatment with 1,25-dihydroxyvitamin D3 [150 IU/Kg (3.75 μg/Kg) once a day, for 15 days] to non-diabetic and streptozotocin-induced diabetic rats. The results indicate that treatment with 1,25-dihydroxyvitamin D3 had minor effects in non-diabetic rats. The same treatment in streptozotocin-induced diabetic rats, although it did not correct the hyperglycemia and hypoinsulinemia induced by the diabetes, caused other actions that could mean beneficial effects on the amelioration of diabetes e.g., it avoided body weight loss, increased calcium and phosphorus plasma levels, and corrected the over-expression of the insulin receptor mRNA species of 9.5 and 7.5 Kb present in the hind limb muscle and heart of these animals. These genomic 1,25-dihydroxyvitamin D3 effects could involve transcriptional mechanisms of repression mediated by vitamin D response elements in the rat insulin receptor gene promoter. Using computer analysis of this promoter, we propose the -249/-235 bp VDRE (5’GGGTGACCCGGGGTT3’) with a pyrimidine (T) in the (+7) position of the3’half-site as the best candidate for negative control by 1,25-dihydroxy-vitamin D3. In addition, posttranscriptional mechanisms of regulation could also be implicated. Thus, computer inspection of the5’untranslated region of the rat insulin receptor pre-mRNA indicated the presence of a virtual internal ribosome entry segment whereas the computer inspection of the3’untranslated region localized various destabilizing sequences, including various AU-rich elements. We propose that through these virtual cis-regulatory sequences, 1,25-dihydroxyvitamin D3 could control the translation and stability of insulin receptor mRNA species in the hind limb muscle and heart of diabetic rats.
Action and variation potential electrical signals in higher plants
(African Science Publications, 2021-01-01) Ndung’u Ruth, Wairimu; Kamweru Paul, Kuria; Kirwa Abraham, Tuwei
This review evaluates the types of electrical signals (ESs) in plants, generation and propagation of various ESs, their ways of transmission within the plant body and their corresponding physiological significance. It also outlines abiotic factors, e.g., light, temperature, water content as stimuli on the electrical potential (EP) of the plants. The paper also summarizes a review of the effects of ESs on photosynthesis, the mechanisms of the effects, and its physiological role in plants. Local irritations of plants induce various photosynthetic responses including fast and long-term inactivation of photosynthesis and its activation. The paper also reviews the concept of plant energy harvesting. The measurement techniques used for ESs in plants including extracellular measurement and intracellular measurement are also reviewed. A brief summary of the applications of these methods for investigating ES in plants is also given.
Acute cigarette smoke exposure induces oxidative damage and inflammation in Wistar rats: impact on lungs and erythrocytes
(African Science Publications, 2021-01-01) Shahdat, Hossain; Marzan, Sarkar; Sujan, Bhowmick; Jakir, Hussain; Mahmudul, Hasan; Borhan, Uddin; Md. Asaduzzaman, Khan; Taslima, Nahar
Smoking of cigarettes worsens morbidity and mortality rates by prompting cancer, pulmonary, cardiovascular, and oral diseases. Despite having all these severe risks of smoking, the habit is unacceptably widespread, particularly among teenagers in many countries, including Bangladesh. In this investigation, the acute effect of cigarette smoking on oxidative stress and inflammation (Tumor Necrosis Factor- α (TNF-α)) has been analyzed in the cigarette smoke (CS)-exposed rats. Exposure of smoke in vivo significantly increased the levels of Lipid Peroxide (LPO) and TNFα in the experimental rats, when compared to those of the control rats. Furthermore, washed erythrocytes isolated from control rats were exposed directly to CS in vitro. The time-dependent exposure of smoke to erythrocytes increased the oxidative stress in the erythrocytes, as indicated by increased levels of LPO in the erythrocytes. The toxic effect of acute cigarette smoke was also visible in the morphological studies of erythrocytes. Cigarette smoke-exposed erythrocytes revealed numerous leakage, breaks and membrane blobs in the plasma membrane of erythrocytes. Our results thus suggest that cigarette smoke not only affects the lung tissues but may also deteriorate the morphology of erythrocytes by instigating the oxidative stress in the erythrocytes.
Ameliorating effects of Cissus populnea aqueous stem bark extract on some parameters in diabetic Wistar rats
(African Science Publications, 2021-04-05) Aondoaseer Kasar, Ndubisi A Chidi, Adilieje Chioma M and Ibegbu Madu D
This study investigated the effects of aqueous stem bark of Cissus populnea (C.p) extract on some parameters in diabetic Wistar rats. Fresh stem bark of C.p was air dried, pulverized, and mixed with distilled water at room temperature for 72 h; then flittered (11 µm) and the dried filtrate (C.p extract) was used for the animals treatment, which was in 5 groups of 6 rats each: Group 1: normal control, Group 2: treated with 200 mg/kg body weight (b.w) of C.p extract; Group 3: treated with 500 mg/kg b.w of C.p extract, Group 4: treated with 100 mg/kg b.w metformin, while Group 5 untreated, after groups 2-5 were induced with diabetes mellitus with alloxan, the study was for 21 days. Treatment of groups 2 and 3 with C.p extract restored the blood glucose to level comparable to group 1, p > 0.05, but significantly different to group 5, p < 0.05. Treatment of group 3 with C.p extract stabilized the antioxidant enzymes activity without significant difference p > 0.05, when compared to groups 1 and 4; but significantly differed from group 5, p < 0.05. The pancreatic histology of groups 2 and 3 appeared normal, while group 5 had tissue atrophy. The results showed that C.p extract had potentials to modulate glucose, MDA and antioxidant enzymes activity, with no pathological effect on the pancreas. Therefore, further work is suggested for possible extrapolation to diabetic treatment.
Ameliorative potentials of methanol leaf extract of Newbouldia laevis on monosodium glutamate induced toxicity in female albino rats
(African Science Publications, 2020-07-09) Itez, Paul; Aloh, S Godwin; Osuocha, Kelechi U.; Iwueke, Adaku V.; Chukwu, Ezinne C.
Newbouldia laevis is a valuable tropical plant belonging to the family of Bigoniaceae. The plant is believed by most herbal practitioners to be the tree of fertility and of immense medicinal benefits to humans. This study examined ameliorative potencies of Newbouldia laevis on monosodium glutamate induced toxicity in female albino rats for 14 days. Group A received 800 mg/kg body weight of Monosodium Glutamate (MSG), while Group B received 8,000 mg of MSG + 400 mg of extract. Group C received 8,000 mg of MSG and 600 mg of N. laevis. Group D received feed and water. Group E received 200 mg of extract and Group F received 8,000 mg of MSG. Results showed no significant difference (p > 0.05) in Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALP) and Total Protein (TP) of rats exposed to MSG + extracts and MSG-alone. Significant (p < 0.05) elevation in Alanine Transferase (ALT) and serum albumin were recorded for rats exposed to MSG + 400 mg and 200 mg of extract. There was no significant difference in cholesterol level in rats exposed to MSG alone compared to other groups. Significant elevation in urea level occurred in rats exposed to 8,000 mg MSG + 600 mg of the extract, reduction occurred in those exposed to 8,000 mg MSG + 400 mg of the extract. Those exposed to normal saline and 200 mg of extract leveled up with rats exposed to MSG. Study indicates protection of liver architecture and ameliorating effect of N. laevis on MSG intoxication.
Analysis of certain biochemical indices on alloxan induced diabetic rats administered with protein isolated and purified from Vernonia amygdalina
(African Journal of Biological Sciences, 2019-04-12) Ihimire I.G.*, Kayode E.A. and Osagie V.E.
This study investigated the effect of protein isolate from leaf extract of Vernonia amygdalina in diabetic rats. Thirty (30) adults male Wistar rats were randomly divided into six (6) groups of five (5) each based on their body weight. Diabetes was induced with administration of alloxan, 150 mg/kg body weight (i.p). Group A served as the control and received 1 mL/kg body weight of 5% ethanol being solvent used, Group B received 1 mL alloxan containing 150 mg/kg only. Group C, D, E and F were respectively alloxanized but treated with 1%, 3%, 5% and 7% of protein isolate obtained from V. amygdalina leaves for 14 days. On the 15th day, the animals were humanely sacrificed and their liver homogenates were prepared. Standard biochemical procedures were adopted for determination of catalase (CAT), superoxide dismutase (SOD) activities, Malondialdehyde (MDA) and glucose levels. Data were subjected to one-way Analysis of Variance (ANOVA) with Tukey-Kramer multiple comparison post-hoc test using Graph Pad, version 6 software. Results showed that CAT activity in alloxan-induced untreated rats (1.17 μmole H2O2) was significantly (p < 0.05) lower than observed in control rats (2.10 mole H2O2). Treatment with the respective doses recorded comparable values to those observed in control rats. Similar observation was seen with SOD data. Rats treated with 7% protein isolate recorded the most significant (p < 0.05) decrease in serum glucose level. The study suggests that the protein isolate possesses anti-diabetic and hypoglycaemic effects on alloxan-induced diabetic rats.
Anaplerosis in cancer: Another step beyond the warburg effect
(Scientific Research Publishing, 2016-10) Ochoa-Ruiz, Estefania; Diaz-Ruiz, Rodrigo
Biosynthesis is up-regulated in tumors and thus the demand for anabolic intermediates is increased. The metabolic routes providing the building blocks for macromolecules are thus a very attractive target as they are not normally up-regulated in a normal quiescent cell. Some routes for glycolysis-derived intermediates production have been identified, but these do not constitute the whole pool of biosynthetic molecules in the cell, as many of these derive from mitochondria in the Krebs cycle. Indeed, this metabolic pathway is considered a “biosynthetic hub” from which anabolism is fed. If a metabolite efflux is indeed occurring, anaplerotic reactions must keep a steady supply of substrates. In spite of this obvious relevance of anaplerosis, it has been poorly characterized in the malignant cell context. Glutaminolysis and and pyruvate carboxylation are two pathways that function in an anaplerotic fashion. In spite of the increasing evidence implicating these two processes in cancer metabolism their role as intermediate providers is overlooked. In this review we analyze the implications of an active anaplerosis in cancer and we discuss experimental evidence showing the relevance of these metabolic routes in tumor physiology.
Antagonistic conflict of Trichoderma harzianum against fruit rots pathogens
(African Science Publications, 2020-10-05) Udhav Narba, Bhale
Present work was investigated the study of infected fruits and its pathogens and checked the antagonistic activity with Trichoderma harzianum. Ficus carica was to be found highly mycotoxic due to more pathogens followed by Manilkara zapota and Punica granatum Antagonistic potentials of T. harzianum was tested against fruit rots pathogens in vitro conditions. Dual culture experiment was conducted for pathogens and T. harzianum and data revealed that, the percent inhibition of test fungi proved to be more than 50% antagonism over control. In case of Fusarium oxysporum (83.34%) showed highest antagonistic activity followed by others. It was found highly inhibited the radial growth over control. In case of F. oxysporum, overgrew beyond 80% (R1-scale) and Phytophthora parasitica, Cladosporim cladosporioides, Penicillium digitatum, Mucor sp, Fusarium sp and Geotrichum candidum overgrew beyond 70% (R2-scale). In case of Bipolaris cactivora, overgrow on bioagent (R5-scale) and Aspergillus flavus, A. tamari and Rhizopus nigricans were found the bioagent and test fungi contact point after inoculation (R4-scale). The results of this study identify as promising biological control agents for further testing against rots disease on fruits.
Anti-browning methods on fresh-cut fruits and fruit juice: A Review
(African Science Publications, 2020-10-05) Afoakwah, A. N.
Enzymatic browning is an economically important disorder that degrades the sensory characteristics, and prevent consumer from purchasing fresh-cut fruits and vegetables. Prevention and control of enzymatic browning in fresh-cut fruit products is imperative. This has led to extensive studies being conducted and many methodologies being explored with positive outcomes. However, concerns over off-odors, safety of food, has resulted in few browning inhibitors showing the potential for usage in the fresh-cut fruit-industry. A significant goal has been the discovery of natural compounds with health benefits, which has the potential to provide safe and effective control of enzymatic browning in fresh-cut fruits. Studies on effective combinations of diverse treatments reviewed shows that it has the potential to effectively elongate the shelf-life of fresh-cut fruits while inhibiting the activities of polyphenol oxidase (PPO), thereby maintain product quality and safety.
Antibiotic resistance of bacteria responsible for lower respiratory tract infections seen in the University Hospital of Befelatanana Antananarivo Madagascar
(African Science Publications, 2021-04-05) Zafindrasoa Domoina Rakotovao-Ravahatra*, Fidiniana Mamy Randriatsarafara and Andriamiadana Luc Rakotovao
The majority of bacteria responsible for Lower Respiratory Tract Infections (LRTIs) are multiresistant to antibiotics. The objectives of this study are to describe the antibiotic resistance of these bacteria in LRTIs and to describe the factors associated with these infections. It is a prospective study of 54 respiratory samples of patients with LRTIs for a period of six months from July 2019 to December 2019 in the laboratory of the University Hospital of Befelatanana Antananarivo. The microbiological results showed 12 (22%) isolates of nonfermenting gram-negative bacilli, 10 (19%) isolates of streptococci and 6 (11%) isolates of enterobacteria. Regarding the isolates of nonfermenting gram-negative bacilli, the antibiotic resistance, varies from 42% (amikacin) to 100% (cotrimoxazole). Concerning the isolates of streptococci, it varies from 0% (vancomycin) to 80% (penicillin G). And the antibiotic resistance of the isolates of enterobacteria varies from 0% (imipenem and amikacin) to 100% (amoxicillin). Concerning the associated factors, subjects aged 40 and over (58.6%) (p = 0.84; NS), men (71.4%) (p = 0.01) and subjects hospitalized in intensive care units (70.3%) (p = 0.004) are the most affected by LRTIs. In brief, the knowledge of antibiotic resistance of bacteria responsible for LRTIs allows better patient management.
Antimicrobial-resistant Salmonella spp. isolated from retail farmed shrimp in Kuala Lumpur
(African Science Publications, 2020-10-05) Goh Ee, Vian; Nor-Khaizura, M. A. R.; Nor Ainy, Mahyudin
Antimicrobial resistant Salmonella is recognized as a potential food safety threat and its prevalence in farmed shrimps is very concerning. However, information about antimicrobial resistant Salmonella in retail farmed shrimps in Malaysia is very limited. Therefore, this study was aimed at determining the level of Salmonella contamination of farmed shrimps at selected retails in Kuala Lumpur and antibiotic resistance pattern of Salmonella isolated from retail farmed shrimps. Farmed shrimp samples were collected from selected hypermarkets and indoor markets. Salmonella was detected by conventional methods. All presumptive colonies of Salmonella were subjected to antimicrobial susceptibility test. A high rate of Salmonella contamination was detected (n = 9, 60%) with an estimated Salmonella load ranging between 0 and >800 x 108 cfu/ml. All isolates (100%) were resistant to at least one antimicrobial agent, and 17 isolates (94.4%) were multidrug-resistant. 2 isolates (11.1%) were resistant to all eight types of antimicrobial agents. High rates of resistance were observed for erythromycin (100%), doxycycline (77.8%), tetracycline (72.2%), nalidixic acid (61.1%), ampicillin (55.6%) and chloramphenicol (44.4%). Findings from the present study provide insight on antibiotic resistant Salmonella contamination in retail farmed shrimps and suggest its potential food safety risk to the public. These data are valuable to warrant further investigation of risk management and public health strategies.
Antioxidant properties of Psidium guajava leaf extract on paraquat induced hepatotoxicity and oxidative stress
(African Science Publications, 2021-01-01) Okorondu, M. M.; Okorondu., S. I.
Thirty healthy male rats were used for the in vivo experiment. Animals received 3.5 mg/kg of Paraquat (PQ) intraperitoneally on the 15th day of experiment. Extracts were administered daily for thirty (30) days using normal saline. Liver parameters were analyzed to assess hepatoprotection. Malondialdehyde concentration was estimated to assess peroxidation. Glutathione (GSH) concentration was estimated to assess non-enzymatic antioxidant status. Activities of antioxidant enzymes were further used to assess antioxidant capacity of Psidium guajava (PG) against PQ-induced oxidative damage. Hematological indices were evaluated to assess the effect of PG on haemopoesis. Histological study of the liver was also carried out to find out the level of effectiveness of PG. The antimicrobial activity of the extract was also determined. Results showed that there was a significant increase in ALT and AST activities, albumin/globulin ratio, malondiadehyde (MDA), following PQ exposure at (p < 0.05). There was also a significant decrease of total protein and globulin concentrations, Packed Cell Volume (PCV), Red Blood Cell (RBC) count, Superoxide Dismutase (SOD), and GSH after PQ exposure at (p < 0.05). The histological result showed that PG leaf extract significantly improved changes in oxidative stress parameters, blood parameters, and hepatotoxicity induced by PQ administration at p < 0.05. Thus, PG leaf ethanol extract may be recommended in hepatotoxicity.
Applying Surface-Based DNA Computing for Solving the Dominating Set Problem
(Scientific Research Publishing, 2012-07) Taghipour, Hassan; Rezaei, Mahdi; Esmaili, Heydar A.
The surface-based DNA computing is one of the methods of DNA computing which uses DNA strands immobilized on a solid surface. In this paper, we applied surface-based DNA computing for solving the dominating set problem. At first step, surface-based DNA solution space was constructed by using appropriate DNA strands. Then, by application of a DNA parallel algorithm, dominating set problem was resolved in polynomial time.
Artificial Neural Network (ANN) and regression model for predicting the Albumin to Globulin (A/G) ratio in a serum protein electrophoresis test
(African Journal of Biological Sciences, 2019-07-08) Akshansh Mishra
Multiple myeloma affects the several parts of bodies such as the spine, skull, pelvis and ribs. The cause of multiple myeloma is not known properly. The poor prognoses is associated with most cancers creates a sense of urgency for the brains behind healthcare Artificial Intelligence (AI) research. AI is able to detect cancer and other diseases earlier than possible through standard diagnostic methods, which could be lifesaving for future patients. The main objective of the research paper is to predict the Albumin to Globulin (A/G) ratio obtained by the electrophoresis test by developing regression model and Artificial Neural Network (ANN) model. The results obtained showed that the Mean Square Error (MSE) obtained by ANN model is less than the MSE obtained by the regression model.
Assessment of body size and catch per unit effort of Nile perch (Lates Niloticus) caught using different fishing gears at Magu district in Lake Victoria, Tanzania
(African Science Publications, 2020-10-05) Renalda N., Munubi; Julitha N., Nyakibinda
This study was conducted to assess body size distribution and Catch Per Unit Effort (CPUE) of Nile perch (Lates cf. niloticus) captured using three common fishing gears at Magu district in Tanzania. Three landing sites along Lake Victoria were selected for this assessment. Each site was visited twice per week for two months. At each site 10 boats were identified based on the gear used and randomly selected for fish count. Ten fish per boat were taken for weight and length measurements. The results show that the main fishing gears used to catch fish at all sites were gillnet (GN), long line (LL) and beach seine (BS). Mean length of captured fish recorded from each gear were 33.7, 41.5 and 43.8 for beach seine, gillnets and long lines respectively, which was below the minimal required length of 50 cm. Large proportion of small landed fish were observed in vessels fishing with beach seine, this was due to illegal nature of the beach seine, where by fishermen used small mesh sizes of 10 mm to 12 mm. However, beach seine had higher CPUE (kg/gear/day) (44.9) and gillnet had the lowest (22.6). This study revealed that the mean length from all sites were below the legal minimum size required by the Tanzanian government, suggesting that all beaches are involves in over exploration of fish.
Assessment of performance of wastewater stabilization ponds using faecal indicator bacteria reduction efficiency in a tropical environment
(African Science Publications, 2021-04-05) Khasisi D. Lukhabi*, Muia A. Wairimu and Kipkemboi K. Julius
Egerton University (EU) uses Wastewater Stabilization Ponds (WSPs) for wastewater treatment. An adjoining wetland with gravel bed substrate and freesurface flow meant to polish discharge before releasing into River Njoro is currently non-operational. The current study aimed at establishing the performance of WSPs in terms of concentration and reduction efficiencies of Faecal Indicator Bacteria (FIB); Total Coliforms (TC) and Escherichia coli (E. coli). Wastewater samples were collected weekly for one month from mid- November to mid-December 2017. Total Coliforms and E. coli were isolated using selective and differential media following Membrane Filtration (MF) method. Colonies were cultured on Chromocult Coliform Agar (CCA) and enumerated using standard procedures for examination of water and wastewater. The results were expressed as Colony Forming Units (CFUs) per 100 ml of the original sample. The inlet showed highest concentration of FIB which reduced along the treatment pathway. Total Coliforms and E. coli ranged between 2.5 × 108 - 2.9 × 1011 and 5.9 × 105 - 1.8 × 1010 CFUs/100 ml respectively with cumulative reduction efficiencies between 2 to 4 log units for E. coli and 2 to 3 log units for TC in the two maturation ponds. Although concentration of FIB in EU WSPs reduces along the treatment pathway, the effluent quality is above recommended international standards for discharge into surface waters. The trend is attributed to lack of frequent monitoring, insufficient maintenance, together with short- circuiting effect due to by-passing of wastewater in the design of the new pond system.
Assessment of vessel and fiber characteristics of Blighia sapida Konig. and Lecaniodiscus cupanoides Planch ex Benth. growing in rainforest and derived savanna areas of Edo state, Nigeria
(African Journal of Biological Sciences, 2020-04-06) Okoegwale, E. E.; Idialu J. E., O. E. Ehilen; Ogie-Odia, E. A.
This study was carried out to assess the vessel and fiber dimensions and characteristics of Blighia sapida Konig. and Lecaniodiscus cupanoides Planch ex Benth. growing in the rainforest and derived savanna regions of Edo state, Nigeria. In both taxa, rainforest species possessed wider and longer vessels than the derived savanna species. Also, significant variations were recorded in taxa vessel wall thickness between the two ecozones. The derived savanna plants had thicker vessel wall to counterbalance the water stress prevalent in that environment. In both species, vessel members lacked tails. Also, taxa fibers were of short and medium lengths. Significant variations between fiber lengths of species occurring in both habitats were not encountered. Fiber elements of taxa were of moderately thick wall while fiber/vessel length ratio was greater than 1 in both taxa. Although runkel ratios of both species studied were less than 1, they may however not be suitable for high grade pulp because of their low fiber length values. The study has revealed that the woods are suitable for various end uses because of the presence and distribution of vessels and fiber with thick walls.
Association of XbaI GLUT1 Polymorphism with Susceptibility to Type 2 Diabetes Mellitus and Diabetic Nephropathy
(Scientific Research Publishing, 2016-03) Ramadan, Ragaa A.; Zaki, Ahmed M.; Magour, Gehan M.; Zaki, Moyassar A.; Aglan, Sarah A.; Madkour, Marwa A.; Shamseya, Mohammed M.
Objectives: Diabetic nephropathy (DN) is one of the chronic microangiopathic complications of type 2 diabetes (T2DM) and has become the most frequent cause of end-stage renal disease. The XbaI polymorphism in the glucose transporter (GLUT1) has been suggested in the development of DN. We examined the association between XbaI polymorphism of GLUT1 and susceptibility to T2DM and development of DN. Methods: The study included 227 T2DM patients divided into 107 without DN (DM − DN) and 120 with DN (DM + DN), in addition to 100 apparently healthy controls. Genotyping was done by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Results: The GLUT1 XbaI T allele was associated with increased susceptibility to T2DM, when comparing the healthy controls to the whole diabetic group, odds ratio (OR) = 1.899, 95% confidence interval (CI) (1.149 - 3.136), p = 0.011. This association was also significant between healthy controls and DM − DN OR = 1.997 (1.079 - 3.699), p = 0.026 as well as between healthy controls and DM + DN OR = 1.818 (1.016 - 3.253), p = 0.042. However there was no significant association of XbaI polymorphism with DN when comparing DM − DN to DM + DN OR = 0.910 (0.474 - 1.747), p = 0.777. Conclusion: XbaI T allele is associated with increased susceptibility to T2DM, but not to development of DN. Further studies are needed to replicate such findings.
The ATPase activity of molecular chaperone HSP60 is inhibited by immunosuppressant mizoribine
(Scientific Research Publishing, 2012-04) Tanabe, Masako; Ishida, Ryuichi; Izuhara, Fumiko; Komatsuda, Atsushi; Wakui, Hideki; Sawada, Kenichi; Otaka, Michiro; Nakamura, Nobuhiro; Itoh, Hideaki
The molecular chaperone HSP60 is a chaperonin homolog of GroEL. We had previously shown that the immunosuppressant mizoribine is bound directly to HSP60 and inhibited its chaperone activity. However, the inhibitory mechanisms of HSP60 by mizoribine have not yet been fully understood. In the present study, we investigated the influence of mizoribine on a folding cycle of HSP60 and co-chaperone HSP10. Our results showed that mizoribine inhibited the folding cycle of HSP60/HSP10. The ATPase activity of HSP60/HSP10 was decreased in the presence of mizoribine and the dissociation of HSP10 from HSP-60 was also decreased by mizoribine. The same functions of GroEL and/or GroES were slightly affected by mizoribine. Based on our findings, we discuss the inhibitory mechanisms of HSP60 by mizoribine.
Autophagic processes of normal and malignant metabolic pathways
(African Journal of Biological Sciences, 2019-07-08) Aurelian Udristioiu* and Manole Cojocaru
Autophagy is a cellular process that maintains the homeostasis of the normal cell, but autophagic dysfunction is associated with human diseases, such as cancer. In normal cells, the initial signal to form auto-phagosomes is by the class III phosphatidyl-inositol (PI) 3 kinase complex consisting of sequence genes, Beclin1/Atg6 and class III PI3K (Vps34). This process is negatively regulated by binding of Bcl-2 family members such as Bcl-xL to Beclin1 preventing Beclin1 binding to the PI3K-III complex and thereby reducing autophagy. In cancer, the autophagy can be neutral, tumor-suppressive, or tumor-promoting in different contexts. Genomic analysis of human cancers indicates that the loss or mutation of core autophagy Atg genes, whereas oncogenic events that activate autophagy and lysosomal biogenesis have been identified in malignant diseases. Optimal combination of inductors or inhibitors of autophagy with chemo or radiotherapy in a variety of tumor type, in different phases, can be successful approaches for improve the effect of anticancer therapies.

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