Alpha-glucosidase Levels Research Articles

The Effect of Neutral Alpha-Glucosidase on Semen Parameters

Introduction: The objective of this study was to investigate the relationship between the activity of neutral α-glucosidase in seminal plasma and semen quality and to explore the effect of secretory capability of the epididymis on male fertility. Methods: A retrospective analysis of 542 men treated in the Center for Reproductive Medicine and Infertility from February to December 2022, the semen parameters and neutral α-glucosidase were tested and compared among different groups. These 542 men included normozoospermia, oligospermia, asthenospermia, and teratozoospermia. Results: There was statistical difference in neutral alpha-glucosidase (NAG) level among different groups with different sperm concentration, motility, and morphology (p < 0.001). The NAG activity in seminal plasma was positively correlated with ejaculate volume and sperm concentration; meanwhile, a very weak positive correlation was found between NAG level and sperm motility, sperm morphology, respectively. Conclusions: Our results indicated that the secretion of NAG affected the volume, concentration, motility, and morphology of sperm to a certain extent. Given that NAG is a specific and marker enzyme in epididymis, where is the site of sperm maturation, we can conclude that there is a close relationship between NAG and sperm quality. Therefore, seminal plasma NAG has a definite clinical value in helping diagnosis of male infertility.

Alpha-amylase and alpha-glucosidase upregulated glucose homeostasis in high-fat fed wistar rats supplemented with cocoa flavonoid-rich aqueous

This study investigates the impact of cocoa (Theobroma Cacao L.) flavonoid-rich aqueous supplementation on alpha-amylase and alpha-glucosidase enzymes, influencing glucose homeostasis in Wistar rats. Over 12 weeks, Wistar rats underwent a high-fat diet induction for obesity. Group assignments included a negative control on a normal diet, a positive control on a normal diet with 600 mg/kg cocoa-containing flavonoid-rich water extract, a fat-treated group on a high-fat diet with the same cocoa extract, and an untreated fat group exclusively on a high-fat diet. The cocoa extract was orally administered for 14 days, evaluating various metabolic parameters. Results showed that the rats displayed improved glucose tolerance, reduced fasting serum glucose, and enhanced insulin sensitivity with increased alpha-amylase and alpha-glucosidase levels compared to the untreated high-fat group and controls. This study suggests that cocoa-derived polyphenols hold potential in mitigating high-fat diet-induced adverse effects on glucose metabolism by regulating the secretion of alpha-amylase and alpha-glucosidase in rats.

Seminal Plasma Examination Test Result Agreements Using the WHO Manual Recommendation: With Semi-Automatic and Automatic Methods

Objective: To analyze the suitability of the measurement results of neutral alpha-glucosidase and fructose in seminal plasma, between the manual method recommended by the World Health Organization (WHO) Sixth Edition and the semi-automatic method, using Biosystems BTS 350 and the automatic method using Biosystems A15.Material and Methods: This study involved 47 subjects at the Andrology Outpatient Department of Dr. Soetomo General Academic Hospital; from October 2022 and February 2023. The measurement of neutral alpha-glucosidase and fructose levels in seminal plasma was conducted, via three different approaches: the manual method, as recommended by the WHO Sixth Edition, the semi-automatic Biosystems BTS 350, and the automatic Biosystems A15. The manual method recommended by the WHO Sixth Edition was employed as the reference system.Results: The average disparity in neutral alpha-glucosidase levels among the manual method, as recommended by the WHO Sixth Edition, compared to the semi-automatic and automatic methods were recorded as: -1.0215 IU/l and -2.3428 IU/l, respectively. Similarly, the fructose levels exhibited differences of -2.1234 mmol/l and 2.2834 mmol/l. Notably, within the method comparisons, 44 values of neutral alpha-glucosidase levels fell within the limit of agreement, while fructose levels showed 44 and 45 values within the agreement limit.Conclusion: The results obtained from the manual method, as recommended by the WHO Sixth Edition, demonstrated agreement with the measurements of neutral alpha-glucosidase and fructose obtained when using both the semi-automatic and automatic methods.

Seminal Plasma Examination Test Result Agreements Using the WHO Manual Recommendation: With Semi-Automatic and Automatic Methods

Objective: To analyze the suitability of the measurement results of neutral alpha-glucosidase and fructose in seminal plasma, between the manual method recommended by the World Health Organization (WHO) Sixth Edition and the semi-automatic method, using Biosystems BTS 350 and the automatic method using Biosystems A15.Material and Methods: This study involved 47 subjects at the Andrology Outpatient Department of Dr. Soetomo General Academic Hospital; from October 2022 and February 2023. The measurement of neutral alpha-glucosidase and fructose levels in seminal plasma was conducted, via three different approaches: the manual method, as recommended by the WHO Sixth Edition, the semi-automatic Biosystems BTS 350, and the automatic Biosystems A15. The manual method recommended by the WHO Sixth Edition was employed as the reference system.Results: The average disparity in neutral alpha-glucosidase levels among the manual method, as recommended by the WHO Sixth Edition, compared to the semi-automatic and automatic methods were recorded as: -1.0215 IU/l and -2.3428 IU/l, respectively. Similarly, the fructose levels exhibited differences of -2.1234 mmol/l and 2.2834 mmol/l. Notably, within the method comparisons, 44 values of neutral alpha-glucosidase levels fell within the limit of agreement, while fructose levels showed 44 and 45 values within the agreement limit.Conclusion: The results obtained from the manual method, as recommended by the WHO Sixth Edition, demonstrated agreement with the measurements of neutral alpha-glucosidase and fructose obtained when using both the semi-automatic and automatic methods.

Presence of key cholinergic enzymes in human spermatozoa and seminal fluid†.

Little is known about the non-neuronal spermic cholinergic system, which may regulate sperm motility and the acrosome reaction initiation process. We investigated the presence of the key acetylcholine (ACh)-biosynthesizing enzyme, choline acetyltransferase (ChAT), and the acetylcholine-degrading enzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and two ACh-receptors in human spermatozoa and seminal plasma. Fresh ejaculates were used for intra- and extracellular flow cytometric analysis of ChAT, AChE, BChE, and alpha-7-nicotinic and M1-muscarinic ACh-receptors in sperm. For determining the source of soluble enzymes, frozen seminal samples (n = 74) were selected on two bases: (1) from vasectomized (n = 37) and non-vasectomized (n = 37) subjects and (2) based on levels of alpha-glucosidase, fructose, or zinc to define sample subgroups with high or low fluid contribution from the epididymis and seminal vesicle, and prostate, respectively. Flow cytometric analyses revealed that ChAT was expressed intracellularly in essentially all spermatozoa. ChAT was also present in a readily membrane-detachable form at the extracellular membrane of at least 18% of the spermatozoa. These were also highly positive for intra- and extracellular BChE (>83%) and M1 (>84%) and α7 (>59%) ACh-receptors. Intriguingly, the sperm was negative for AChE. Analyses of seminal plasma revealed that spermatozoa and epididymides were major sources of soluble ChAT and BChE, whereas soluble AChE most likely originated from epididymides and seminal vesicles. Prostate had relatively minor contribution to the pool of the soluble enzymes in the seminal fluid. In conclusion, human spermatozoa exhibited a cholinergic phenotype and were one of the major sources of soluble ChAT and BChE in ejaculate. We also provide the first evidence for ChAT as an extracellularly membrane-anchored protein.

Comprehensive evaluation of hematospermia in patients with acute epididymitis compared to patients with isolated hematospermia.

Among the most commonly known causes of hematospermia are infections in the genitourinary tract, but no study exists that has comprehensively investigated hematospermia in patients with acute epididymitis. To assess the impact of hematospermia in patients with acute epididymitis and its association with clinical, microbiological, and semen parameters. Since May 2007, a total of 324 sexually active patients with acute epididymitis were recruited in a prospective cohort study. Patients received a comprehensive medical and sexual history, and clinical, sonographic, laboratory, and microbiological diagnostics. Antibiotic therapy was given according to European Association of Urology guidelines. Semen analysis was offered 14 days after the first presentation and initiation of therapy. Since 2013, a separate control group of 56 patients presenting with isolated hematospermia (=no other urogenital symptoms) was prospectively recruited, and differences between the groups were statistically evaluated. Of 324 patients with acute epididymitis, 50 patients (15%) had self-reported hematospermia. This occurred with a median of 24h before the onset of scrotal symptoms and was associated with significantly elevated prostate-specific antigen levels compared to 274 patients without hematospermia (3.1vs. 1.8ng/ml, p<0.01). The two most common etiological pathogens were Escherichia coli and Chlamydia trachomatis, and the bacterial spectrum was comparable in both epididymitis subgroups (p=0.859). Semen analysis at 14 days still showed hematospermia in 24% of patients associated with massive leukocytospermia. Compared to the hematospermia control group, the two epididymitis subgroups showed significantly increased inflammation markers (pH, leukocytes, and elastase), reduced sperm concentration, and reduced levels of alpha-glucosidase and zinc (always p<0.01). In sexually active patients who develop acute epididymitis, self-reported hematospermia is evident in 15% of patients as early as one day before the onset of scrotal symptoms. Conversely, none of the 56 patients presenting with isolated hematospermia developed epididymitis within the next 4 weeks.

Spermogram abnormalities correlate with epididymo-vesicular biochemical markers in infertile men: an analytical cross-sectional study

Context and objective. The sperm tests explore testicular spermatogenesis, epididymal maturation and storage, prostate and seminal vesicle secretions and genital tract patency. The aim of this study was to establish a correlation between spermogram abnormalities and epididymalvesicular biomarkers of spouses in infertile couples. Methods. An analytical cross-sectional study was conducted from November 15, 2020 to October 15, 2021 at the Centre Universitaire de Diagnostic du Graben in Butembo, DRCongo. The correlation between spermogram abnormalities and epididymal biomarkers was investigated by determining the Pearson correlation coefficient. Results. One hundred ninety-two patients were involved. The alphaglucosidase concentration was low in 31.2 % of cases of altered spermograms against 7.3 % of the spouses with normal spermograms. The fructose concentration was also low in 37.5 % of cases of altered spermograms against 4.2% of normal spermograms. Semen volume was associated with reduced fructose concentration while sperm concentration, motility, vitality and morphology were correlated with reduced alphaglucosidase levels. Chlamydia (OR: 13.7), Gonorrhoea (OR: 3.8), anti-sperm antibody serology (OR: 6.05), history of STI (OR: 3.61), smoking (OR: 5.62), leukocytospermia (OR: 6.23) as well as varicocele and obesity were significantly correlated with spermogram abnormalities. The latter were dominated by oligoasthenoteratozoospermia (39.6%) and consisted of various types of abnormalities including azoospermia (15.6 %). Conclusion. The functional status of the epididymo-vesicular and genital tract influences semen quality. Genitou-inary tract infections, even if asymptomatic, are the major etiological factor of infertility. The topographical diagnosis requires the contribution of sperm biochemical markers for a judicious therapeutic approach.

502-P: Urinary Levels of Deoxyribonuclease-1 and Lysosomal Alpha-Glucosidase Were Associated with the Progression of Diabetic Nephropathy

Recent reports showed early progressive renal function decline precedes the onset of microalbuminuria, indicating the need for new factors predicting diabetic nephropathy (DN) that work alone or as a complement to urinary albumin and eGFR. To identify urinary proteins associated with DN, we carried out a 2D-DIGE-based proteomic analysis using the urine obtained from healthy control subjects (H; n=8), type 2 diabetic patients without nephropathy (T2DM; n=16), and stage II DN patients (DN2; n=16). From the total 3034 protein spots detected, a total of 34 proteins were identified as the candidate protein differentially excreted in DN2 or T2DM. Thirty proteins out of 34 candidates were then validated by multiple reaction monitoring assay using an independent sample set (H: n=14, T2DM: n=13, DN2: n=14, stages III to IV DN: n=17), where 26 proteins were validated to be differentially excreted in DN. Among them, the levels of deoxyribonuclease-1 and lysosomal alpha-glucosidase were significantly correlated with both ACR and eGFR, and were also significantly lower in patients with an eGFR &amp;lt; 60 compared with patients with an eGFR ≥ 60. We further analyzed gene expressions of DNase I and lysosomal alpha glucosidase in kidneys of DN patients using Nephroseq database (https://www.nephroseq.org), and found that DNase I gene was significantly downregulated in DN tubulointerstitum and glomeruli, and that lysosomal alpha glucosidase gene tend to decreased in DN tubulointerstitum. Finally, the urinary DNase I levels were found to be higher in patients who progressed to a more severe DN stage or had early renal decline than in patients who did not. These findings suggest a possible role for the identified proteins in the progression of DN, although further validation studies are required. Disclosure Y. Kaburagi: None. E. Ito: None. H. Unoki-Kubota: None. Funding Japan Society for the Promotion of Science

Targeted screening for the detection of Pompe disease in patients with unclassified limb-girdle muscular dystrophy or asymptomatic hyperCKemia using dried blood: A Spanish cohort

We aimed to screen for Pompe disease in patients with unclassified limb-girdle muscular dystrophy (LGMD) or asymptomatic hyperCKemia using dried blood spot (DBS) assays. Subsequently, we aimed to calculate the diagnostic delay between initial symptom presentation and the diagnosis. A prospective, multicenter, observational study was conducted in 348 patients: 146 with unclassified LGMD and 202 with asymptomatic or paucisymptomatic hyperCKemia. We quantified levels of acid alpha-glucosidase (GAA) from dried blood spots analyzed fluorometrically. The test was positive in 20 patients, and Pompe disease was confirmed by genetic testing in 16. Undiagnosed Pompe disease was detected in 7.5% of patients with LGMD and in 2.5% of patients with persistent, idiopathic elevation of serum creatine kinase. The c.-32-13 T > G mutation was found most commonly. The diagnostic delay was 15 years on average. In conclusion, DBS tests are useful and reliable screening tools for Pompe disease. We recommend the dried blood spot test to be included in the diagnostic work-up of patients with unclassified myopathies with proximal weakness and/or hyperCKemia of unknown cause and, when positive, to define the diagnosis, it will have to be confirmed by biochemical and/or molecular genetic analysis.

Chitotriosidase and lysosomal enzymes as potential biomarkers of disease progression in amyotrophic lateral sclerosis: A survey clinic-based study

The aim of this study was to determine if blood chitotriosidase (Chit) activity and lysosomal enzyme levels might represent markers of disease activity and progression in amyotrophic lateral sclerosis (ALS).It is a survey clinic-based study performed in a tertiary ALS centre. Blood samples were obtained from 76 patients with ALS in different stages of the disease and from 106 healthy individuals serving as controls. Chit activity and the levels of acid alpha-glucosidase, acid alpha-galattosidase A, beta-glucocerebrosidase, and alpha-l-iduronidase were detected using the dried blood spots (DBS) technique. The CHIT1 genotype for exon 10 duplication and for the p.G102S variant was also determined. Chit activity was significantly higher in ALS patients than in healthy individuals. This difference was independent of the genotypes at CHIT1 functional variants. Chit were significantly higher in 34 rapidly progressing patients as compared to 42 with slowly progressive disease. Acid alpha-glucosidase was higher than normal and significantly correlated with the severity of the disease. Glucocerebrosidase and alpha-l-iduronidase activity were significantly lower in patients than in the controls. Alpha-galactosidase A was higher than normal only in rapidly progressing patients.We have employed a very simple and affordable laboratory test to measure blood Chit and lysosomal enzymes activity which could be easily included in the screening of ALS patients recruited in clinical trials. Remarkably, high levels of chitinase and alpha-galactosidase A could help to distinguish patients with fast progression from those with slow progression of the disease and possibly to follow the effects of treatments on neuroinflammation and autophagy.

Heterozygous individuals with mild phenotype in late-onset glycogen storage disease type 2: a new cohort of patients?

Late-onset glycogen storage disease type 2 (GSD2) is a genetic but heterogeneous disorder, which may present anywhere along a continuum of severity from an isolated hyperCKemia to a profound, generalized muscle weakness with pulmonary involvement. The gold standard for diagnosis is confirmation of low or absent levels of acid alpha-glucosidase (GAA) enzyme activity (usually in the range of 1-40% of normal levels), which is confirmed only in some cases by molecular analysis of the GAA gene. In the literature, heterozygous individuals are usually considered to be asymptomatic, although they can have reduced enzymatic activity. Since enzyme replacement therapy (ERT) became available in 2006, it has improved the prognosis for severe infantile-onset Pompe disease, as well as for late-onset forms by improving muscle/respiratory function and/or stabilizing clinical progression. Because the disease is now treatable, it is essential to understand which patients may benefit from ERT.

Muscle biopsy in Pompe disease

Pompe disease (PD) can be diagnosed by measuring alpha-glucosidase levels or by identifying mutations in the gene enzyme. Muscle biopsies can aid diagnosis in doubtful cases. A review of muscle biopsy from 19 cases of PD (infantile, 6 cases; childhood, 4 cases; and juvenile/adult, 9 cases). Vacuoles with or without glycogen storage were found in 18 cases. All cases had increased acid phosphatase activity. The vacuole frequency varied (almost all fibers in the infantile form to only a few in the juvenile/adult form). Atrophy of type 1 and 2 fibers was frequent in all forms. Atrophic angular fibers in the NADH-tetrazolium reductase and nonspecific esterase activity were observed in 4/9 of the juvenile/adult cases. Increased acid phosphatase activity and vacuoles were the primary findings. Most vacuoles were filled with glycogen, and the adult form of the disease had fewer fibers with vacuoles than the infantile or childhood forms.

Slow digestion of synthesized highly branched starch-based structures at the mucosal alpha-glucosidase level suggest slow glucose delivery to the body

Slow digestion of synthesized highly branched starch-based structures at the mucosal alpha-glucosidase level suggest slow glucose delivery to the body

Laparoscopic Inguinal Hernia Repair in Men With Lightweight Meshes May Significantly Impair Sperm Motility

To compare quality of life and fertility aspects after laparoscopic inguinal hernia repair in men using a heavyweight or lightweight mesh. The use of lightweight meshes in laparoscopic inguinal hernia repair could have beneficial effects on quality of life and preservation of the spermatic structures due to a decreased foreign-body reaction. A total of 59 male patients planned for primary, unilateral or bilateral inguinal hernia repair were randomized between a standard polypropylene (Marlex) or lightweight mesh (Vypro II, TiMesh). Main outcome measures were fertility aspects, assessed preoperatively and at 1-year follow-up by semen analysis and scrotal ultrasonography. Secondary outcomes were quality of life (SF-36 and McGill Pain Questionnaire) and recurrence up to 1 year postoperatively. Patients operated on with a VyproII or TiMesh mesh exhibited a decreased sperm motility (vs. preoperatively) compared with Marlex patients, respectively -9.5% and -5.5% versus +2% (P = 0.013). When the results after uni- and bilateral hernia repair were analyzed separately, this difference only remained significant in the bilateral hernia subgroup: -10% for VyproII and -17% for TiMesh versus +1% for Marlex (P = 0.037). Other fertility parameters (sperm concentration, morphology, and alpha-glucosidase level) were unchanged. There were no differences at any study point between the 3 groups regarding quality of life. Only for resumption of sport activities was a small advantage noted for VyproII versus Marlex patients (P = 0.045). After 1 year, no recurrences were observed; 3 patients (6%) complained of chronic disabling pain. Our data suggest that the use of lightweight meshes for laparoscopic inguinal hernia repair in male patients negatively influences sperm motility, without any benefit on quality of life. These alterations might be important in a subgroup of young male patients operated on laparoscopically for a bilateral hernia. This study was registered in the clinicaltrials.gov database (ID number NCT00925067).

Envejecimiento y calidad seminal: un análisis de 9.168 casos en Córdoba, Argentina

Concomitantly with the actual trend towards later fathering, more detailed studies are necessary to establish the relationship between male age and seminal features. The objective of the present paper was to evaluate the relationship of men age with semen quality and with the seminal levels of epididymal and accessory gland markers. The study was conducted as a retrospective study of 9168 cases obtained from the Andrology and Reproduction Laboratory in Cordoba, Argentina for 10 years (1995-2004) (men ages 20 to 77). An important number of factors such as abstinence time, toxic habits, work conditions and drugs consumption has been statistically considered. The parameters measured were: seminal volume, sperm concentration, total sperm count, sperm motility, morphology and viability. Seminal levels of alpha-glucosidase, fructose and citric acid were also evaluated. We detected a significant decrease in seminal volume, sperm count, motility, viability and normal morphology, and a reduction in alpha-glucosidase and fructose levels in relation to age. Since semen quality is a tool for fertility prognosis estimation, the weight of evidence indicates that men may become progressively less fertile as they get older. Couples who decide to delay childbearing should be warned about this matter.

Overweight and seminal quality: a study of 794 patients

To evaluate sperm quality, levels of markers of epididymal and accessory gland function, and T in semen from men grouped according to their body mass index (BMI). Blind prospective study. Andrology and reproduction laboratory in Cordoba, Argentina (2006-2007). Seven hundred ninety-four men. None. In semen samples, sperm quality (volume, density, motility, morphology, viability, hypoosmotic swell test, and nuclear maturity) and levels of neutral alpha-glucosidase, fructose, citric acid and T. Multivariate analysis showed a negative association between BMI and motility, rapid motility and neutral alpha-glucosidase levels, and a positive association between BMI and seminal fructose levels. No associations were found among BMI and sperm concentration, the other parameters evaluated, or seminal T levels. Results found in our study support a deleterious effect of obesity on seminal quality, probably by alterations in the function of the epididymis (i.e., in epididymal maturation).

G.P.8.05 The pharmacological chaperone AT2220 increases mutant acid alpha-glucosidase levels and reduces tissue glycogen in a mouse model of Pompe disease

Pompe disease, also known as glycogen storage disease type II (GSD II), is an autosomal recessive neuromuscular disorder caused by mutations in the gene encoding the lysosomal hydrolase, acid alpha-glucosidase (GAA). GAA deficiency results in lysosomal glycogen accumulation in multiple tissues including skeletal and cardiac muscle and leads to muscle weakness, reduced cardiac function, and respiratory insufficiency. As a potential treatment for Pompe disease, we are developing the pharmacological chaperone AT2220 (1-deoxynojirimycin-HCl) that directly binds to and stabilizes GAA.

Epididymal and sex accessory gland secretions in transfusion-dependent beta-thalassemic patients: evidence of an impaired prostatic function.

Neutral alpha-glucosidase levels as epididymal marker, fructose levels as vesicular marker, zinc, citric acid and prostate specific antigen levels as prostatic markers were measured in the seminal plasma of eight transfusion-dependent beta-thalassemic patients in order to study epididymal and sex accessory gland secretions (eighteen subjects served as controls). FSH and LH as well as total and free testosterone were detected displaying unaltered serum values. Ejaculate of patients showed normal sperm count and low sperm motility, in the meantime seminal plasma exhibited unaltered both neutral alpha-glucosidase and fructose values but low levels of zinc, citric acid and prostate specific antigen were noticed as well. These data suggest an impaired prostatic secretion in the thalassemic patients studied. A local iron toxicity on the prostatic tissue could be supported by the decrease of its specific markers observed only in the subgroup of patients with high ferritin serum levels.

Relationship between semen quality and seminal plasma components: alpha-glucosidase, fructose and citrate in infertile men compared with a normospermic population of Tunisian men

The aim of this study was to evaluate the correlation between the secretory function of the male accessory glands and sperm parameters in normospermic controls and infertile patients. One hundred and fifty-nine men were investigated: they were composed of two groups: normospermic (n = 37) and infertile (n = 122) men with altered sperm characteristics. These infertile men were divided into the following groups: asthenozoospermia (n = 38), teratozoospermia (n = 40) and asthenoteratozoospermia (n = 44). The patients underwent semen analysis and measurements of fructose, neutral alpha-glucosidase and citric acid. The level of fructose was significantly decreased in asthenozoospermic and increased in asthenoteratozoospermic men. It was significantly correlated with semen volume, sperm count, motility and morphology. The seminal alpha-glucosidase levels were significantly correlated with semen volume and pH and citric acid was significantly correlated with pH. Thus, alpha-glucosidase and citric acid levels were associated with semen pH. The significant correlation between semen parameters, accessory glands and epididymal functions highlights the relationship between semen and normal genital tract function.

Isolations of α-glucosidase-producing thermophilic bacilli from hot springs of Turkey

From 42 different hot springs in 6 provinces belonging to distinct geographical regions of Turkey, 451 thermophilic bacilli were isolated and 67 isolates with a high amylase activity were selected to determine the alpha-glucosidase production capacities by using pNPG as a substrate. Alpha-glucosidase production capacities of the isolates varied within the range from 77.18 to 0.001 U/g. Eleven of our thermophilic bacilli produced alpha-glucosidase at significant levels comparable with that of the reference strains tested, thus five strains, F84b (77.18 U/g), A333 (48.64 U/g), F84a (36.64 U/g), E134 (32.09 U/g), and A343 (10.79 U/g) were selected for further experiments. 16S rDNA sequence analysis revealed that these selected isolates all belonged to thermophilic bacilli 16S rDNA genetic group 5, four of them representing the genus Geobacillus, while strain A343 had an uncultured bacterium as the closest relative. Changes of alpha-glucosidase levels in the intracellular and extracellular fractions were determined during 48-h cultivation of A333, A343, F84a, F84b, E134, and the reference strain G. stearothermophilus ATCC 12980. According to alpha-glucosidase production type and enzyme levels in intracellular and extracellular fractions, Geobacillus spp. A333, F84a and F84b were defined as extracellular enzyme producers, whereas the thermophilic bacterium A343 was found to be an intracellular alpha-glucosidase producer, similar to ATCC 12980 strain. Geobacillus sp. E134 differed in alpha-glucosidase production type from all tested isolates and the reference strain; it was described as a membrane-associated cell-bound enzyme producer. In this study, apart from screening a great number of new thermophilic bacilli from the hot springs of Turkey, which have not yet been thoroughly studied, five new thermostable alpha-1,4-glucosidase-producing bacilli that have biotechnological potential with alpha-glucosidases located at different cell positions were obtained.