Gender Variation, subject dispersion and citation impact in dental research: A bibliometric analysis of publications from 2009-2021.

Aim: This study probed into the gender variation, subject dispersion and citation impact of dental research with an objective to highlight the increasing influence of female authors in the field of dentistry. Methodology: The research employed bibliometric techniques to highlight gender variation in dental research as demonstrated in the Saudi Dental Journal (SDJ), over a period of thirteen years, 2009-2021. The examination comprised SDJ publications indexed in PubMed, with citation data extracted from Google Scholar on July 2023. The analysis encompassed the progressive growth of papers, authors, and citations, the gender distribution of authors, the co-authorship structure, subject dispersion, and collaboration patterns based on affiliation, both national and international. Results: 625 SDJ publications were identified in the PubMed database from 2009 to 2021. There was a notable rise in the volume of papers and the number of authors per year. The citation impact analysis revealed that these 625 papers achieved an average of 26 citations each. Remarkably, the representation of female authors increased from 0.47 to 2.23 authors per paper during the study period. The authorship pattern largely showed single-authorship, closely followed by a three-author pattern. Almost half the papers (48%) were a collaboration between male and female authors, with female authors solely producing about 15% of papers.The topological classification of papers revealed that the most considerable number of papers were on Periodontics, with the least number focusing on Oral and Maxillofacial Surgery. Female authors prominently contributed to Pediatric Dentistry and Periodontics papers. Conclusion: The study illustrates an encouraging trend of heightened female authorship in dental research over the years. Their increasing engagement not only enriches the academic diversity but also impacts the progressive evolution of dental science, contributing to a more inclusive and balanced society.

Level of evidence analysis of the Saudi Dental Journal: A bibliometric analysis of publications from 2012 to 2021.

Objectives: The Level of Evidence (LOE) ranking system is used to measure the methodological quality of research. This study aimed to analyze and evaluate the trends of LOEs in articles published in the Saudi Dental Journal (SDJ) between 2012 and 2021. Methodology: The bibliometric details of all articles published from 2012 to 2021 were extracted from the SDJ website. All articles, expect editorials, were included in the analysis. The articles were divided based on LOEs, dental specialties, number of authors, and centers. The citation metrics were obtained from Google Scholar, and the statistical analysis was performed using JMP Pro 15.2.0 software. Results: Five hundred twenty-two articles were selected for analysis. They had an average of 21.19 citations per article, and a growing trend in the number of articles was observed. Authors from 40 countries contributed to the articles, with the most contributions from the Kingdom of Saudi Arabia. Most articles (n = 269; 51.53%) were LOE IV and V, while a low proportion (5.56%) were LOE I articles. Aside from miscellaneous articles, periodontics composed most of the LOE I studies, followed by endodontics, and oral and maxillofacial Surgery (OMFS). Orthodontics had the highest number of LOE II studies, pediatric dentistry had the most LOE IV, and prosthodontics had the most LOE V studies. No significant correlations were found between LOE and the number of authors or centers. However, a significant correlation was found in the distribution of LOE contributed by academic institutes. Conclusion: The study results highlight that most articles were LOE IV and V, whereas nominal LOE I articles were found. Furthermore, there is a need to encourage dental scientists to carry out high-quality evidence studies. Professional dental societies can play a pivotal role in this regard.

Bibliometric Analysis of the 100 Most-Cited Articles on Periodontics in the Arab World.

AIM: Periodontics is a branch of dentistry that deals with diseases of the supporting and investing structures of the teeth including the gingiva, cementum, periodontal ligament, and alveolar bone. The current study aimed to scrutinize the bibliometric indicators of the 100 most-cited articles on periodontics contributed by authors affiliated with the Arab countries. RESEARCH METHODOLOGY: The bibliometric research method was used for the 100 most-cited articles retrieved from the Scopus database on May 9, 2023. The keywords periodontitis, periodontology, gingivitis, periodontal, gingiva, and periodontium were inserted, and then the Arab countries were selected from the country's filter. The 100 most-cited articles were accessed. The bibliometric indicators such as periodic distribution of articles, their study design, nature of research, contributed by different Arab countries, international research collaboration, and author's used keywords were analyzed. Microsoft Excel version 16 (Microsoft Corporation, Washington, United States), VOSviewer (Centre for Science and Technology Studies, Leiden University, The Netherlands), and SPSS Statistics version 27 (IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp.) were used for data analysis. RESULTS: A slow progress (4.50%) was found in periodontics literature before 2000 in the Arab countries, but a significant growth (75%) was recorded during the past 10 years (January 1, 2014, to May 9, 2023). The 100 most-cited articles on periodontics by the Arab countries were published from 1995 to 2021, and these articles gained citations with an average of 92.18 citations per articles. Case-control and review studies were the preferred study designs, and periodontology and implantology were the top two subject categories. About one-third of the articles were published in the Journal of Periodontology and the Journal of Clinical Periodontology. Saudi Arabia contributed the highest number of the most-cited articles, followed by Egypt and Jordan, but the articles contributed by the United Arab Emirates were the most influential. The United States and Germany were the top-ranked countries in international research collaboration. CONCLUSION: The findings demonstrate that periodontics research increased remarkably during the past 10 years. Saudi Arabia stands not only on the topmost rank in overall research productivity in the Arab countries but also surpasses the rest of the Arab countries in the 100 most-cited articles. Saudi Arabia contributed 26 articles with the United States, while Jordan contributed the highest ratio of indigenous research.

Enzymatic hydrolysis of low temperature alkali pretreated wheat straw using immobilized ß-xylanase nanoparticles.

A low temperature alkali (LTA) pretreatment method was used to treat wheat straw. In order to obtain good results, different factors like temperature, incubation time, NaOH concentration and solid to liquid ratio for the pretreatment process were optimized. Wheat straw is a potential biomass for the production of monomeric sugars. The objective of the current study was to observe the saccharification (%) of wheat straw with immobilized magnetic nanoparticles (MNPs). For this purpose, immobilized MNPs of purified ß-xylanase enzyme was used for hydrolysis of pretreated wheat straw. Wheat straw was pretreated using the LTA method and analyzed by SEM analysis. After completion of the saccharification process, saccharification% was calculated by using a DNS method. Scanning electron micrographs revealed that the hemicellulose, cellulose and lignin were partially removed and changes in the cell wall structure of the wheat straw had caused it to become deformed, increasing the specific surface area, so more fibers of the wheat straw were exposed to the immobilized ß-xylanase enzyme after alkali pretreatment. The maximum saccharification potential of wheat straw was about 20.61% obtained after pretreatment with optimized conditions of 6% NaOH, 1/10 S/L, 30 °C and 72 hours. Our results indicate the reusability of the ß-xylanase enzyme immobilized magnetic nanoparticles and showed a 15% residual activity after the 11th cycle. HPLC analysis of the enzyme-hydrolyzed filtrate also revealed the presence of sugars like xylose, arabinose, xylobiose, xylotriose and xylotetrose. The time duration of the pretreatment has an important effect on thermal energy consumption for the low-temperature alkali method.

Effective utilization of magnetic nano-coupled cloned ß-xylanase in saccharification process.

The ß-xylanase gene (DCE06_04615) with 1041 bp cloned from Thermotoga naphthophila was expressed into E. coli BL21 DE3. The cloned ß-xylanase was covalently bound to iron oxide magnetic nanoparticles coated with silica utilizing carbodiimide. The size of the immobilized MNPs (50 nm) and their binding with ß-xylanase were characterized by Fourier-transform electron microscopy (FTIR) (a change in shift particularly from C-O to C-N) and transmission electron microscopy (TEM) (spherical in shape and 50 nm in diameter). The results showed that enzyme activity (4.5 ± 0.23 U per mL), thermo-stability (90 °C after 4 hours, residual activity of enzyme calculated as 29.89% ± 0.72), pH stability (91% ± 1.91 at pH 7), metal ion stability (57% ± 1.08 increase with Ca2+), reusability (13 times) and storage stability (96 days storage at 4 °C) of the immobilized ß-xylanase was effective and superior. The immobilized ß-xylanase exhibited maximal enzyme activity at pH 7 and 90 °C. Repeated enzyme assay and saccharification of pretreated rice straw showed that the MNP-enzyme complex exhibited 56% ± 0.76 and 11% ± 0.56 residual activity after 8 times and 13 times repeated usage. The MNP-enzyme complex showed 17.32% and 15.52% saccharification percentage after 1st and 8th time usage respectively. Immobilized ß-xylanase exhibited 96% residual activity on 96 days' storage at 4 °C that showed excellent stability.

Scientometric evaluation of endodontic publications by Gulf Cooperation Council region in 21st century.

OBJECTIVES: The appraisal of research productivity is one of the key indicators to evaluate any area of knowledge. The current study aimed to analyze the Scopus-indexed publications on endodontics produced by Gulf Cooperation Council (GCC) region from 2000 to 2020. METHODOLOGY: The dataset was extracted in May 2021 from Elsevier's Scopus database. Two keywords ("endodontic" and "endodontics") were entered into the basic search with the Boolean operator of OR for a period of 20 years from 2000 to 2020. RESULTS: Overall, the GCC region contributed 2.82% of the global endodontic research. This share has shown a remarkable increase between 2001 and 2020 from 0.82% to 7.20%. About 60% of documents' volumes were produced during the 2016-2020 period. Around 80% of research was produced by Saudi Arabia, while research articles produced by Kuwait gained the highest citation impact. Out of the ten productive institutions, nine belonged to Saudi Arabia and one was from Kuwait. The majority of research collaboration was conducted with the United States, but research articles produced in collaboration with Japan yielded the highest citation impact. CONCLUSION: The study highlighted various scientometric attributes of endodontic publications produced by GCC affiliated researchers. The ongoing growth of endodontic literature by GCC countries along with the increasing international collaboration is considered aspiring.

Antidiarrheal and antispasmodic activities of Trillium govanianum rhizomes extract: involvement of calcium channel blockade.

The antidiarrheal effect of methanolic extract of Trillium govanianum Wall. ex D. Don (Melanthiaceae alt. Trilliaceae) was studied at doses of 12.5, 25, and 50 mg/kg in different animal models of diarrhea including castor oil (6 mL/kg), magnesium sulfate (2 gm/kg), sodium picosulfate (2 mL/kg) and lactitol (0.25 mL/kg). The antispasmodic effect of T. govanianum was studied on isolated rabbit's jejunum, using acetylcholine as tissue stabiliser and verapamil as calcium channel blocker. T. govanianum attenuated the diarrhea by producing a significant decrease in the number and weight of stool, and an increase in stool latency time. T. govanianum completely inhibited both spontaneous as well as high potassium induced contractions of isolated rabbit's jejunum, which was analogous to verapamil. Moreover, T. govanianum produced a right shift in calcium concentration response curve, confirming its calcium channel blocking activity. These findings provide scientific ground to its medicinal use in diarrhea and gut spasms.

Comprehensive investigation of multiples factors in sulfuric acid pretreatment on the enzymatic hydrolysis of waste straw cellulose.

The prerequisite for cellulosic biochemical production from lignocellulosic materials is efficient enzymatic hydrolysis that is a complicated heterogeneous catalytic process and affected by the complex lignin-cellulose-hemicellulose network. Understanding the main influencing factors for enzymatic hydrolysis is of substantial significance to guide the design of a biorefinery process. An experimental study of the pretreatment indicated that acid pretreatment is preferable for herbaceous feedstocks. Therefore, the classic dilute sulfuric acid pretreatment was utilized to hydrolyze and remove hemicellulose from three representative types of agricultural straws at various intensities. From the enzymatic hydrolysis of residual cellulose perspective, the crystallinity index and enzyme accessibility of the pretreated materials were also mathematically correlated to hemicellulose removals, respectively. For the better insight and understanding of the mathematical logics, the linear and nonlinear kinetic models were therefore compared, and the relationship was established by the five-parameter logistic equations and Allosteric sigmoidal models with well fittings.

Biosynthesis of Polyhydroxyalkanoates (PHAs) by the Valorization of Biomass and Synthetic Waste.

Synthetic pollutants are a looming threat to the entire ecosystem, including wildlife, the environment, and human health. Polyhydroxyalkanoates (PHAs) are natural biodegradable microbial polymers with a promising potential to replace synthetic plastics. This research is focused on devising a sustainable approach to produce PHAs by a new microbial strain using untreated synthetic plastics and lignocellulosic biomass. For experiments, 47 soil samples and 18 effluent samples were collected from various areas of Punjab, Pakistan. The samples were primarily screened for PHA detection on agar medium containing Nile blue A stain. The PHA positive bacterial isolates showed prominent orange-yellow fluorescence on irradiation with UV light. They were further screened for PHA estimation by submerged fermentation in the culture broth. Bacterial isolate 16a produced maximum PHA and was identified by 16S rRNA sequencing. It was identified as Stenotrophomonas maltophilia HA-16 (MN240936), reported first time for PHA production. Basic fermentation parameters, such as incubation time, temperature, and pH were optimized for PHA production. Wood chips, cardboard cutouts, plastic bottle cutouts, shredded polystyrene cups, and plastic bags were optimized as alternative sustainable carbon sources for the production of PHAs. A vital finding of this study was the yield obtained by using plastic bags, i.e., 68.24 ± 0.27%. The effective use of plastic and lignocellulosic waste in the cultivation medium for the microbial production of PHA by a novel bacterial strain is discussed in the current study.

A techno-practical method for overcoming the biotoxicity and volatility obstacles of butanol and butyric acid during whole-cell catalysis by Gluconobacter oxydans.

BACKGROUND: Butyric acid is a platform chemical material, the production of which has been greatly stimulated by the diverse range of downstream applications in many industries. In particular, higher quality butyric acid used in food and medicine, is more dependent on microbiological production methods. Hence, the bio-oxidation of butanol to butyric acid has been identified as a promising method with good potential economic and environmental benefits. However, both butanol and butyric acid are usually intensively toxic to most microorganisms as well as the bio-oxidation pathway. To develop a green, efficient and competitive microbiological method is the primary work to overcome the bottleneck of butyric acid industry. RESULT: A combined bioprocess was designed with alternative whole-cell catalysis for butyric acid bio-conversion from butanol by Gluconobacter oxydans in a sealed-oxygen supply bioreactor (SOS). In the operation system, the escape of volatile substrates and toxic chemicals to cells can be avoided by the use of a sealed bioreactor, combined with the rejuvenation of cells by supplying energy co-factors. Finally, during a one-batch whole-cell catalysis, the utilization rate of substrate increased from 56.6 to 96.0% by the simple skill. Additionally, the techno-practical bioprocess can realize the purpose of cell-recycling technology through the rejuvenation effect of co-factor. Finally, we obtained 135.3 g/L butyric acid and 216.7 g/L sorbose during a 60-h whole-cell catalysis. This techno-practical technology provides a promising approach to promote the industrial production of butyric acid with more competitiveness. CONCLUSION: The techno-practical biotechnology has powerfully promoted the process of butyric acid production by microorganisms, especially makes up for the lack of aerobic fermentation in the industry, and surmounts the shortcomings of traditional anaerobic fermentation. At the same time, this technically practical system provides a promising approach for the promotion of the industrial production of butyric acid in a more competitive manner.

Bibliometric analysis of Neurosciences research productivity in Saudi Arabia from 2013-2018.

OBJECTIVE: To review the dynamics of neuroscience research in the Kingdom of Saudi Arabia (KSA) from 2013-2018. METHODS: Subject category of Neuroscience was selected in the SciVal feature of Scopus database, which includes all relevant categories of the field limiting it to Saudi Arabia. RESULTS: Saudi Arabia is ranked 39th in publishing neuroscientific research worldwide. The number of yearly published articles has increased from 123 to 332 during the time period between 2013 and 2018. King Saud University & King Abdul Aziz University & their corresponding regions namely Western and Central regions are the major contributors to publications. Neuroscientists working in Saudi Arabia have collaboration with scientists from all over the world. The top 10 preferred journals are all international. In subcategories of neuroscience, developmental neuroscience seems the one that needs attention. CONCLUSION: Neuroscience research is on the rise in KSA. Older and well-established institutions like King Saud University & King Abdul Aziz University have taken lead in publishing neuroscientific research. International collaboration in all subfields of neuroscience is substantial. Eastern Southern and Northern regions and developmental neuroscience require more focus and funding.

Research Productivity in the Health Sciences in Saudi Arabia: 2008-2017.

The purpose of this study was to analyze the published research on health sciences carried out by researchers in Saudi Arabia in the last decade by assessing bibliometric output. Data for 2008 to 2017 was retrieved from Scopus. During this period, there was significant growth, from 1332 publications in 2008 to 5529 in 2017, with an average annual growth rate of 14.1%. King Saud University was the most productive institution. Most of the published research was done in collaboration with Egypt. The subject area of medicine was predominant with the main publication source being the Saudi Medical Journal, Life Science Journal, the Acta Zhengzhou University Oversea Version, and the Annals of Saudi Medicine, primarily in the form of original research articles. The growing trend in publications is a sign of the increasing quality of education and more research and development activities, which are made possible by a sufficient budget allocation to these activities during the last decade.

Age-related Oral Changes and Their Impact on Oral Health-related Quality of Life among Frail Elderly Population: A Review.

BACKGROUND: In the present-day world, the aging elderly across the world are living longer. Most people are expected to live well into their sixties and even beyond. The increasing life expectancy of the aging population could be due to increased availability of healthcare facilities and improved quality care provided by them. Alongside increasing life expectancy, the individual's quality of life and also his/her oral health-related quality of life (OHR-QoL) are expected to improve so that they can enjoy their aging life. AIM AND OBJECTIVE: The aim of this review article is to highlight aging-related oral health changes and their impact on the individual's quality of life. REVIEW RESULTS: Age-related oral changes are seen in the tooth structure making the enamel more brittle resulting in severe attrition. Autoimmune diseases like Sjogren's syndrome are followed by decrease in the salivary gland function and the reason is unknown, and medications like antihypertensive and analgesics are associated with the decrease in salivary flow, which increases the patient's risk of developing dental caries, and also make the oral tissues more prone to mucosal infections. Edentulism has also been directly related to masticatory problems and nutritional problems. The studies reported on OHR-QoL of these frail elderly populations have shown lower scores. CONCLUSION: It is important for health professionals, especially those dealing with these frail elderly populations, to have a better understanding of their dental needs and also understand the physiologic changes undergone by them. The health professionals should understand and comprehend the oral health challenges these vulnerable people face. CLINICAL SIGNIFICANCE: Healthcare providers should conduct periodic oral examinations along with general examination and should avoid prescribing medications that have xerostomia as a side effect. The elderly individuals should be encouraged to keep their mouth moist using water or artificial saliva and maintain good oral and denture hygiene.

Blood Epstein-Barr virus DNA does not predict outcome in advanced HIV-associated Hodgkin lymphoma.

In HIV-seronegative patients with advanced Hodgkin lymphoma (HL), Epstein-Barr virus (EBV) viraemia at diagnosis predicts a worse progression-free survival (PFS), independent of the International Prognostic Score. However, its role in HIV-associated HL is uncharacterised. We collected clinico-pathologic and treatment data from a prospective series of 44 HIV-associated HLs from 2000 to 2016. We evaluated circulating EBV DNA as a prognostic factor on uni- and multivariable analyses in relationship to the International Prognostic Index criteria. In 44 patients with HIV-associated HL, EBV was detected by in situ hybridisation in all diagnostic biopsies. Blood EBV DNA was detectable in 26 patients (59%) with a median of 600 copies/mL (range 0-161,000). EBV DNA was independent of CD4 cell count (p = 0.9) or HIV viral load (p = 0.6) and did not predict PFS (HR 1.6, 95% CI 0.39-6.7, p = 0.49). EBV DNA is not a prognostic trait in HIV-associated HL. Prognostication in HIV-associated HL should be solely based on the International Prognostic Index criteria.

Phylogenetic Analysis of Klebsiella pneumoniae from Hospitalized Children, Pakistan.

Klebsiella pneumoniae shows increasing emergence of multidrug-resistant lineages, including strains resistant to all available antimicrobial drugs. We conducted whole-genome sequencing of 178 highly drug-resistant isolates from a tertiary hospital in Lahore, Pakistan. Phylogenetic analyses to place these isolates into global context demonstrate the expansion of multiple independent lineages, including K. quasipneumoniae.

Efficacy of Locally Isolated Lactic Acid Bacteria Against Antibiotic-Resistant Uropathogens.

BACKGROUND: Antibiotic resistance represents a serious global health threat to public health, so infections such as pneumonia and urinary tract infection (UTI) are becoming harder to treat. Therefore, it is necessary to develop an action plan to restrain the problem of antibiotic resistance. One approach in UTI control could be the use of lactobacilli because these indigenous inhabitants in human intestine have been found to play an important role in protecting the host from various infections. OBJECTIVES: We sought to check the efficacy of locally isolated Lactobacillus species to eradicate antibiotic-resistant pathogenic bacteria causing UTI. MATERIALS AND METHODS: Lactic acid bacteria isolated from spoiled fruits and vegetables and grown in MRS medium were screened against multi-drug-resistant Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus fecalis. RESULTS: Fifty-four lactic acid bacteria were isolated from spoiled fruits and vegetables, of which 11 Gram-positive and catalase-negative Lactobacillus isolates were identified by carbohydrate assimilation profiles as Lactobacillus acidophilus, L. paracasei, L. delbrueckii, L. casei, L. helveticus, L. brevis, L. salivarius, L. fermentum, L. rhamnosus, L. animalis, and L. plantarum. The latter organism had the highest abundance of all the samples, so its isolates were also verified through 16S rRNA gene sequencing. The isolated Lactobacilli were screened against multi-drug-resistant uropathogens, viz. C. albicans, P. aeruginosa, K. pneumoniae, E. fecalis, and E. coli. The growth inhibition zone (GIZ) was over 10 mm against all the uropathogenic test organisms, where L. fermentum and L. plantarum strains demonstrated remarkable inhibitory activities against E. coli and E. faecalis, with a GIZ up to 28 mm. The susceptibility test to 16 antibiotics showed multidrug resistance (3 to 5 antibiotics) among all the tested uropathogens. CONCLUSIONS: The obtained results revealed that all the Lactobacillus isolates displayed antimicrobial activity against 6 out of 7 antibiotic-resistant uropathogens, indicating that these bacteria could represent a good ecological plan for the control and prevention of UTI.

Cloning, Purification and Characterization of a Highly Thermostable Amylase Gene of Thermotoga petrophila into Escherichia coli.

A putative α-amylase gene of Thermotoga petrophila was cloned and expressed in Escherichia coli BL21 (DE3) using pET-21a (+), as an expression vector. The growth conditions were optimized for maximal expression of the α-amylase using various parameters, such as pH, temperature, time of induction and addition of an inducer. The optimum temperature and pH for the maximum expression of α-amylase were 22 °C and 7.0 pH units, respectively. Purification of the recombinant enzyme was carried out by heat treatment method, followed by ion exchange chromatography with 34.6-fold purification having specific activity of 126.31 U mg(-1) and a recovery of 56.25%. Molecular weight of the purified α-amylase, 70 kDa, was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at 100 °C temperature and at pH of 7.0. The enzyme activity was increased in the presence of metal ions especially Ca(+2) and decreased in the presence of EDTA indicating that the α-amylase was a metalloenzyme. However, addition of 1% Tween 20, Tween 80 and ß-mercaptoethanol constrained the enzyme activity to 87, 96 and 89%, respectively. No considerable effect of organic solvents (ethanol, methanol, isopropanol, acetone and n-butanol) was observed on enzyme activity. With soluble starch as a substrate, the enzyme activity under optimized conditions was 73.8 U mg(-1). The α-amylase enzyme was active to hydrolyse starch forming maltose.

Thermodynamic and saccharification analysis of cloned GH12 endo-1,4-ß-glucanase from Thermotoga petrophila in a mesophilic host.

The thermotolerant endo-1,4-ß-glucanase gene, of Thermotoga petrophila RKU-1, was cloned and over-expressed in E. coli strain BL21 CodonPlus. Enzyme was purified to homogeneity, producing a single band on SDS-PAGE corresponding to 38 kDa, by purification steps of heat treatment combined with ion-exchange column chromatography. The purified enzyme was optimally active, with specific activity of 530 Umg(-1) against carboxymethyl cellulose (CMC), at pH 6.0 and 95°C and was also stable upto 8 h at 80°C. The enzyme also showed activity against ß-glucan barley: 303 %, laminarin: 13.7 %, Whatman filter paper: 0.017 % with no activity against starch and Avicel. The recombinant enzyme exhibited Km, Vmax and Kcat of 12.5 mM, 735 µmol mg-1min-1 and 2351.23 s-1, respectively against CMC as a substrate. The stable recombinant enzyme manifested half life (t1/2) of 6.6 min even at temperature as high as 97°C, with free energy of denaturation (ΔG*D), enthalpy of denaturation (ΔH*D), and entropy of denaturation (ΔS*D) of 98.2 kJ mol(-1), 528.9 kJ mol(-1), and 1.17 kJ mol(-1)K(-1), respectively at 97°C. In addition, the enthalpy (ΔH*), Gibbs free energy (ΔG*) and entropy (ΔS*) for hydrolysis of CMC substrate by endo-1,4-ß-glucanase were calculated at 95°C as 48.2 kJ mol(-1), 54.6 kJ mol(-1) and -17.4 J mol(-1) K(-1), respectively. The recombinant enzyme saccharified pre-treated wheat straw and bagasse to 3.32 % and 3.2 %, respectively after 6 h incubation at 85°C. Its thermostability, resistance to heavy metal ions and specific activity make this enzyme an interesting candidate for industrial applications.

Purification and characterization of cloned alkaline protease gene of Geobacillus stearothermophilus.

Thermostable alkaline serine protease gene of Geobacillus stearothermophilus B-1172 was cloned and expressed in Escherichia coli BL21 (DE3) using pET-22b(+), as an expression vector. The growth conditions were optimized for maximal production of the protease using variable fermentation parameters, i.e., pH, temperature, and addition of an inducer. Protease, thus produced, was purified by ammonium sulfate precipitation followed by ion exchange chromatography with 13.7-fold purification, with specific activity of 97.5 U mg(-1) , and a recovery of 23.6%. Molecular weight of the purified protease, 39 kDa, was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at 90 °C at pH 9. The enzyme activity was steady in the presence of EDTA indicating that the protease was not a metalloprotease. No significant change in the activity of protease after addition of various metal ions further strengthened this fact. However, an addition of 1% Triton X-100 or SDS surfactants constrained the enzyme specific activity to 34 and 19%, respectively. Among organic solvents, an addition of 1-butanol (20%) augmented the enzyme activity by 29% of the original activity. With casein as a substrate, the enzyme activity under optimized conditions was found to be 73.8 U mg(-1) . The effect of protease expression on the host cells growth was also studied and found to negatively affect E. coli cells to certain extent. Catalytic domains of serine proteases from eight important thermostable organisms were analyzed through WebLogo and found to be conserved in all serine protease sequences suggesting that protease of G. stearothermophilus could be beneficially used as a biocontrol agent and in many industries including detergent industry.

Detection of extended-spectrum ß-lactamases in Klebsiella pneumoniae: comparison of phenotypic characterization methods.

OBJECTIVE: Extended-spectrum ß-lactamase producing K. pneumoniae is a serious threat to the patients. This manuscript shows the comparison of phenotypic characterization methods used for ESBL K. pneumoniae and frequency distribution of these isolates in various clinical samples. METHODOLOGY: Eleven different types of pathological samples collected on various time intervals were analyzed. K. pneumoniae were identified with API 20E system (bioMerieux) and initial screening of ESBL K. pneumoniae was performed using the ceftazidime antimicrobial disc. Double-disc synergy test (DDST) and CLSI confirmatory test were compared for the phenotypic detection of ESBL K. pneumoniae. RESULTS: A total number of 214 ESBL producing K. pneumoniae were isolated from various clinical samples. Frequency distribution of ESBL producing K. pneumoniae was found to be highest among blood 117 (54.7%) and urine 46 (21.5%) samples. Data regarding the use of various interventions among these patients showed most common presence of intravenous line 209 (97.7%) and urinary catheters 46 (21.5%). Comparison of DDST and CLSI confirmatory test showed that the DDST detected 145 (67.8%) isolates while 213 (99.5%) ESBL K. pneumoniae were characterized by CLSI confirmatory test. CONCLUSION: The use of CLSI confirmatory test is very efficient in the early detection of ESBL K. pneumoniae especially when the facilities for molecular characterization are not available.