High Incidence of Antibiotic Resistance in the Uropathogenic Bacteria Associated with Different Urological Diseases and Metabolic Complications: A Single Center Cross-Sectional Study

Urological diseases affect all age groups and are associated with different urinary complications. Presence of pathogenic bacteria complicates the urological diseases such as chronic kidney disease (CKD), kidney stone disease (KSD), emphysematous pyelonephritis (EPN), and urological cancers (UCs) coinciding with urinary metabolic complications. The One Health concept for preventing the spread of antibiotic resistant opportunistic pathogens necessitates detailed investigation on the virulence and the antibiotic sensitivity patterns of the pathogens from the urinary tract infections (UTIs). This cross-sectional study was aimed to profile the pathogenic bacteria associated with different urological diseases that included urine samples from the patients from a tertiary care hospital. The study included 258 patients representing CKD (15.1%), KSD (28.7%), EPN (15.5%), UC (12.0%), and UTI patients without any urological diseases (28.7%) with overall 70.5% patients showing positive urine culture. Furthermore, other than UTI in patients without any urological diseases (100%), higher culture positive cases were seen in KSD (64.9%), followed by CKD (61.5%), EPN (52.5%), and UC (48.4%). Escherichia coli was the most predominant bacteria in UTI (35.1%) and EPN (66.7%). In KSD, Pseudomonas aeruginosa (41.7%), Staphylococcus aureus (18.8%), and Proteus mirabilis (14.6%) were more common. S. aureus (86.7%) was the most isolated bacteria from the UC cases. Overall rate of multidrug resistance (MDR) was 77.8%. All (100%) E. coli, K. pneumoniae, P. mirabilis, and S. aureus strains were MDR. Among the strains, strong biofilm formation was observed in 73.6%, and 66.7% strains were urease positive. Biofilm was positively correlated with MDR and urease activity. The abundance and distribution of bacteria differed among the urological diseases suggesting their association with the urine metabolite profile. Colonization of MDR pathogens in patients with urological diseases is a serious concern requiring steps to control the emergence of drug resistance and their further spread into the ecosystem.

Evaluation of the inhibitory potential of bioactive compounds against SARS-CoV-2 by in silico approach

CONTEXT

The COVID-19 (coronavirus disease 19) pandemic brought on by the SARS-CoV-2 outbreak (severe acute respiratory syndrome coronavirus 2) has stimulated the exploration of various available chemical compounds that could be used to treat the infection. This has driven numerous researchers to investigate the antiviral potential of several bioactive compounds from medicinal plants due to their reduced adverse effects compared to chemicals. Some of the bioactive compounds used in folklore treatment strategies are reported as effective inhibitors against the proliferative and infective cycles of SARS-CoV-2. The secondary metabolites from plants are generally used to treat various diseases due to their intact medicinal properties. The present study analyzes the inhibitory potential of phytochemicals from medicinal plants like Sphaeranthus indicus, Lantana camara, and Nelumbo nucifera against SARS-CoV-2 by molecular docking.

METHODS

Ten druggable protein targets from SARS-CoV-2 are docked against the phytochemicals from the selected medicinal plants. The phytocompounds astragalin, isoquercetin, and 5-hydroxy-7-methoxy-6-c-glycosy flavone were found to have lower binding energy depicting their inhibitive potential compared with the reported inhibitors that are used in the treatment of SARS-CoV-2 infection. The phytocompounds found to have the least binding energy were selected for further analyses. To assess the compounds' potential as drugs, their ADMET characteristics were also examined. Sphaeranthus indicus, Lantana camara, and Nelumbo nucifera six possible compounds were separately screened for ADME and toxicity characteristics; then, the results were analyzed. To assess the impact of the phytocompound binding on the dynamics of SARS-CoV-2 ribonuclease protein NSP15, microsecond-level all atomistic molecular dynamics simulations were performed, and their dynamics were analyzed. Microsecond-level molecular dynamics simulations of both the ligands complexed with NSP15 revealed that the ligand induces allosteric effects on NSP15, which could lead to destabilization of NSP15 hexameric interface and loss of RNA binding. The low binding energy exhibited by the phytochemicals from Lantana camera, Sphaeranthus indicus, and Nelumbo nucifera against the protein targets of SARS-CoV-2 showed inhibitory potential by the selected molecules. Their predicted interference of the enzymes involved in the molecular mechanisms aiding the proliferation of SARS-CoV-2 indicated the inhibitive ability of the phytochemicals.

Biotechnological interventions for the production of forskolin, an active compound from the medicinal plant, Coleus forskohlii

Coleus forskohlii, an Indian-origin medicinal plant is the sole natural source of the labdane terpenoid forskolin (C22H34O7), with growing demand. Forskolin emerged as an industrially important bioactive compound, with many therapeutic applications in human health. It has established potential effects in the treatment of various diseases and conditions such as glaucoma, asthma, obesity, allergies, skin conditions and cardiovascular diseases. Moreover, clinical trials against different types of cancers are progressing. The mechanism of action of forskolin mainly involves activating adenylyl cyclase and elevating cAMP, thereby regulating different cellular processes. For the extraction of forskolin, tuberous roots of C. forskohlii are used as they contain the highest concentration of this metabolite. Approximately 2500 tonnes of the plant are cultivated annually to produce a yield of 2000-2200 kg ha-1 of dry tubers. The forskolin content of the root is distributed in the range of 0.01-1%, which cannot meet the increasing commercial demands from industries such as pharmaceuticals, cosmetics, dietary supplements, food and beverages. Hence, various aspects of micropropagation with different culture methods that employ precursors or elicitors to improve the forskolin content have been explored. Different extraction and analytical methods are also introduced to examine the yield and purity of forskolin. This review discusses the significance, clinical importance, mechanism of action and different approaches used for mass production including tissue culture for the lead compound forskolin to meet market needs.

Differential expression of urease genes and ureolytic activity of uropathogenic Escherichia coli and Pseudomonas aeruginosa isolates in different nutritional conditions

Uropathogens have adaptation strategies to survive in the host urinary tract by efficiently utilizing and tolerating the urinary metabolites. Many uropathogens harbour the enzyme urease for the breakdown of urea and the enzymatic breakdown of urea increases the pH and facilitate the struvite crystallization. In this study, the differential urease activity of uropathogenic Escherichia coli and Pseudomonas aeruginosa strains was investigated under different nutritional conditions. The experiments included measurement of growth, pH, urease activity, NH4-N generation and urease gene (ureC) expression among the bacterial strains under different conditions. Further, the implications of urea breakdown on the struvite crystallization in vitro and biofilm formation were also assessed. The study included urease positive isolates and for comparison urease negative isolates were included. Compared to the urease negative strains the urease positive strains formed higher biofilms and motility. The urease positive P. aeruginosa showed significantly higher (p < 0.01) pH and urease activity (A557-A630) compared to E. coli under experimental conditions. Further, supplementation of glucose to the growth media significantly increased the urease activity in P. aeruginosa and in contrast, it was significantly lower in E. coli. The expression profile of urease gene (ureC) was significantly higher (p < 0.001) in P. aeruginosa compared to E. coli and was consistent with the biochemical results of the urease activity under the nutritional conditions. The differential urease activity under two nutritional conditions influenced the biogenic struvite crystallization. It correlated with the urease activity showing higher crystallization rate in P. aeruginosa compared to E. coli. The results highlight the differential urease activity in two common uropathogens under different nutritional conditions that may have significant role on the regulation of virulence, pathogenicity and in the kidney stone disease.

Emerging cell cycle related non-coding RNA biomarkers from saliva and blood for oral squamous cell carcinoma

The unnotified or undifferentiable early stages of oral squamous cell carcinoma (OSCC) progression are the prime reasons for late-stage detection and poor survival outcomes of oral cancer. This review summarizes the prior research and recent advancements on the influence of dysregulated non-coding RNA (ncRNA) on cell cycle and their employability as diagnostic and prognostic biomarkers of oral cancer. The literature search was performed using the following keywords: 'serum/saliva non-coding RNAs' and 'serum/saliva non-coding RNAs and cell cycle', 'serum/saliva dysregulated ncRNAs and cell cycle', 'Cdk/CKI and ncRNAs', 'tissue ncRNAs' concerning 'oral cancer''. The compiled data focuses mainly on the diagnostic and prognostic significance of MicroRNAs (miRNAs), Circular RNAs (circRNAs), and Long noncoding RNAs (lncRNAs) on oral cancer and all other cancers as well as subject-relevant articles published in languages other than English are beyond the scope of this review and excluded from the study. Moreover, articles focusing on DNA, protein, and metabolite markers are eliminated from the study. While there exist various potential biomolecules such as DNA, RNA, proteins, metabolites, and specific antigens representing predictive biomarkers in body fluids for oral cancer, this review completely focuses on non-coding RNAs restricted to saliva and blood, picking out a few of the reliable ones amongst the recent investigations based on the sophisticated techniques, cohort, and sensitivity as well as specificity, i.e., salivary miR-1307-5p, miR-3928, hsa_circ_0001874 and ENST00000412740, NR_131012, ENST00000588803, NR_038323, miR-21 in circulation. Thus, further studies are required to clinically confirm the usage of these non-invasive biomarkers in oral cancer.

Serum autoantibody profiling of oral squamous cell carcinoma patients reveals NUBP2 as a potential diagnostic marker

Introduction

Oral Squamous Cell Carcinoma (OSCC), a common malignancy of the head and neck region, is frequently diagnosed at advanced stages, necessitating the development of efficient diagnostic methods. Profiling autoantibodies generated against tumor-associated antigens have lately demonstrated a promising role in diagnosis, predicting disease course, and response to therapeutics and relapse.

Methods

In the current study, we, for the first time, aimed to identify and evaluate the diagnostic value of autoantibodies in serum samples of patients with OSCC using autoantibody profiling by an immunome protein array. The utility of anti-NUBP2 antibody and tissue positivity in OSCC was further evaluated.

Results and discussion

We identified a total of 53 autoantibodies with significant differential levels between OSCC and control groups, including 25 that were increased in OSCC and 28 that were decreased. These included autoantibodies against Thymidine kinase 1 (TK1), nucleotide-binding protein 2 (NUBP2), and protein pyrroline-5-carboxylate reductase 1 (PYCR1), among others. Immunohistochemical validation indicated positive staining of NUBP2 in a large majority of cases (72%). Further, analysis of OSCC data available in TCGA revealed higher NUBP2 expression correlated with better disease-free patient survival. In conclusion, the differential serum autoantibodies identified in the current study, including those for NUBP2, could be used as potential biomarkers for early diagnosis or as screening biomarkers for OSCC pending investigation in a larger cohort.

Description and host-range determination of phage PseuPha1, a new species of Pakpunavirus infecting multidrug-resistant clinical strains of Pseudomonas aeruginosa

A new phage PseuPha1, infecting multiple multi-drug resistant strains of Pseudomonas aeruginosa with strong anti-biofilm activities, was isolated from wastewater in India. PseuPha1 showed optimal multiplicity of infection at 10^-3, maintained the infectivity at wide ranges of pH (6-9) and temperature (4-37 ⁰C), and exhibited 50 minutes latent period and a burst size of 200 when tested against P. aeruginosa PAO1. PseuPha1 shared 86.1-89.5% pairwise intergenomic similarity with Pakpunavirus species (n = 11) listed by the International Committee on Taxonomy of Viruses and established distinct phyletic lineages during phylogenetic analyses of phage proteins. While genomic data validated the taxonomic novelty and lytic attributes of PseuPha1, BOX-PCR profiling asserted the genetic heterogeneity of susceptible clinical P. aeruginosa. Our data supported the affiliation of PseuPha1 as a new Pakpunavirus species and provided the first line of evidence for its virulence and infectivity that can be harnessed in wound therapeutics.

Development of a bioink using exopolysaccharide from Rhizobium sp. PRIM17

Biopolymers play a significant role in tissue engineering, including in the formulation of bioinks that require careful selection of the biopolymers having properties ideal for printability and supporting biological entities such as cells. Alginate is one of the most widely explored natural biopolymers for tissue engineering applications due to its biocompatibility, cross-linking ability, hydrophilic nature, and easy incorporation with other polymers. Here, a succinoglycan-like exopolysaccharide (EPS-R17) produced by a bacterial strain Rhizobium sp. PRIM17 was incorporated with alginate for the development of a bioink. The physicochemical characterization of EPS-R17 was performed before formulating the bioink with alginate. The bioink formulation was prepared by mixing different concentrations of EPS with an alginate solution at room temperature under sterile atmosphere. The prepared bioink was characterized for rheological properties, biocompatibility, and a bioplotting experiment was also conducted to mimick the extrusion bioprinting. The EPS-R17 was composed of glucose, galactose, and rhamnose with a molecular weight of 69.98 kDa. It was thermally stable up to 260 °C and showed characteristic FT-IR peaks (1723.3 cm^-1) for succinyl groups. The EPS-R17 showed biocompatibility with keratinocytes (HaCaT), and fibroblasts (HDF) in vitro. The rheological properties of EPS-R17-alginate bioink at different combinations showed shear thinning behavior at 25 and 37 °C. Amplitude sweep measurements showed the gel-like nature of the polymer combinations in the solution system superior to alginate or EPS-R17 alone. The combination of 1 % EPS-R17 and 1.5 % alginate showed good compressive strength and swelling behavior. Extrusion bioprinting mimicked using a bioplotting experiment showed the sustained cell viability in the polymer matrix of EPS-R17-alginate bioink. The results indicate that the EPS-R17 can be used in combination with alginate for bioinks for bioprinting applications for providing physical properties and favorable bioactivities.

Dysbiosis of the oral microbiota composition is associated with oral squamous cell carcinoma and the impact of radiotherapy: a pilot study

Radiotherapy can potentially influence the diversity and composition of the oral microbiome. We performed a study comparing the composition of oral microbiota in patients with oral squamous cell carcinoma (OSCC) before radiotherapy (n = 6), at three months (n = 6), and six months (n = 6) post-radiotherapy, and controls (n = 6). We profiled the oral microbiome by 16S rRNA gene sequencing using Illumina MiSeq. Alpha diversity (Chao1 index) showed significant differences in species richness between healthy controls and OSCC patients (P = 0.014). Conversely, no noteworthy distinctions were observed in the Chao1 index when comparing the pre-and post-radiation periods at both three and six months. The beta diversity of the oral microbiota differed significantly between the controls and OSCC patients (P = 0.014). However, no significant differences were observed in beta diversity between pre- and post-radiation at three months, whereas a significant difference was observed at six months (P = 0.038). Linear Discriminant Analysis Effect Size (LEfSe) demonstrated lower abundance of Corynebacterium, Actinomyces, Veillonella, and Haemophilus, and higher abundance of Selenomonas and Mycoplasma in OSCC patients than in healthy controls. The oral microbiome composition varied among healthy controls, patients with OSCC, and post-radiation therapy patients with OSCC. The observed recovery in the numerical dominance of specific beneficial oral taxa and the reduction in pathogenic bacteria after radiation therapy highlights the need for further investigations into their clinical implications.

Outcomes of ab-interno irrigating goniectomy with trabectome in primary and secondary glaucoma from a single center in India

Purpose

This study was done to report intermediate-term outcomes of irrigating goniectomy with trabectome (trabectome) surgery among different types of glaucoma eyes from a single center in India using a cross-sectional, longitudinal, observational study design.

Methods

Fifty-three patients (58 eyes) with glaucoma who underwent irrigating goniectomy with trabectome between January 2019 and February 2020 were included. Pre-operative data included age, gender, eye laterality, specific diagnosis, number of anti-glaucoma medications (AGMs), prior glaucoma surgeries, visual acuity, and intraocular pressure (IOP) on medical treatment. Post-operative data included IOP changes during the follow-up till 1-year, number of AGMs, any complications, or additional surgical intervention required. Success was defined as IOP ≤ 21 mmHg and ≥ 20% reduction of IOP from pre-operative IOP with no additional glaucoma surgery.

Results

The cohort included 58 eyes (male 53.4% and female 46.6%) ranging from 0.6 to 81 years of age. The average baseline IOP was 23.4 ± 10.2 mmHg and reduced significantly with surgery to 14.1 ± 5.3 mmHg at 1-year follow-up. The AGMs reduced from 2.4 ± 1.4 pre-surgery to 1.6 ± 1.4 at 1-year follow-up. Four eyes required additional glaucoma surgeries for IOP control. The success rate of trabectome with phacoemulsification (88%) was discernibly higher than with trabectome alone (67%). Intra-operatively, significant blood reflux was noticed in 27 eyes, of which only one required tamponading with a viscoelastic agent.

Conclusion

This study concludes that irrigating goniectomy with trabectome has good efficacy and safety in both pediatric and adult cases of glaucoma in terms of IOP control, reduction in AGMs, and low incidence of complications in the Indian population.

Serum and salivary immunoglobulin G4 levels in children with autism spectrum disorder from south India: a case-control study

BACKGROUND

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with wide spectrum of symptoms and few effective therapies. Evidence is suggestive of an association between immune system dysfunction and autism spectrum disorders (ASD) among children with ASD. Immunoglobulins (Ig) are found to be increased in the circulation of individuals with autism. The prospective study was aimed to estimate and correlate the levels of IgG4 in blood and saliva of children with autism.

METHODOLOGY

Blood and unstimulated saliva were collected from 172 children (55 ASD, 57 healthy control, and 60 suspected parasitic infection) aged 0-18 years. Routine blood investigations were done. Serum and salivary IgG4 levels were analyzed using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. Data were subjected to statistical analysis.

RESULTS

ELISA tests showed that the IgG4 levels in serum and saliva were significantly increased (P<0.05) in children with ASD as compared to normal control children. Both serum and saliva IgG4 levels showed a significant positive correlation (P<0.05).

CONCLUSION

IgG4 can be used as a potential biomarker for the early detection of ASD. Further, saliva can be a diagnostic, noninvasive assessment tool for health monitoring of children with autism. Lay summary: The collection of saliva is easy and painless compared to other sample collection methods. The present study shows that, among children with autism, brain-reactive antibody, immunoglobulin G4 (gG4), is increased both in blood and saliva, and there is a significant correlation between the two levels. Therefore, the study recommends IgG4 as a potential biomarker for the early detection of autism, and saliva can be helpful in diagnosis and health monitoring of children with ASD.

Characterization of an exopolysaccharide produced by Enterobacter sp. YU16-RN5 and its potential to alleviate cadmium induced cytotoxicity in vitro

Natural biopolymers have gained remarkable attention for bioremediation particularly in heavy metal removal and oil degradation due to their non-toxic nature and lack of secondary pollution. The exopolysaccharides (EPS) produced by the bacteria have become an important class of biopolymers that are employed in bioremediation. The bacteria isolated from the rhizospheric soil have higher metal tolerance and their EPS are effective in biosorption of heavy metals. Here, we report the characterization of an EPS (EPS-RN5) isolated from the root nodule-associated bacteria, Enterobacter cancerogenus strain YU16-RN5 and its heavy metal biosorption abilities. The bacteria isolated from the West coast of India was cultured in yeast extract mannitol (YEM) medium for EPS extraction and to study the production kinetics on a temporal scale. The biochemical composition, rheological properties and thermostability of EPS-RN5 was characterized by standard methods. The biosorption potential of EPS-RN5 against the selected heavy metals was analyzed by employing the inductively coupled plasma atomic emission spectroscopy (ICP-AES) technique. Further, cell culture experiments were used to test the role of EPS-RN5 in reducing the cytotoxicity exerted by the heavy metals in vitro using a human embryonic kidney cell line (HEK 293T). The bacteria showed good growth in YEM media and the maximum EPS yield was 1800 mg/L at 96 h. The molecular weight of EPS-RN5 was 0.7 × 106 Da and it contained 61.5% total sugars and 14.5% proteins. The monosaccharide composition of the EPS included glucose, sorbose and galactose in the ratio 0.25:0.07:1.0. The EPS-RN5 showed high thermal stability with a degradation temperature of 273 °C. Rheological analysis revealed the non-Newtonian behavior, with pseudoplastic characteristics. The EPS-RN5 efficiently absorbed cadmium and other heavy metals such as mercury, strontium, copper, arsenic, and uranium. In vitro studies revealed significant protective effect against the cadmium-induced cytotoxicity in HEK 293T cells. These results indicate the potential applications of EPS-RN5.

Extraction and characterization of an exopolysaccharide from a marine bacterium

The marine bacterial exopolysaccharides (EPS) have transfigured the biotech sector with their myriad applications and prospects. This work was carried out to characterize and analyze the functional and biochemical properties of an EPS (EPS-DR3A) produced by a marine bacterium, Pseudoalteromonas sp. YU16-DR3A. The bacterium was cultured in Zobell marine broth for the production of EPS. The extracted EPS designated as EPS-DR3A was composed of 69% carbohydrates and 7.6% proteins with a molecular weight of 20 kDa. FT-IR spectra showed the presence of different functional groups. The monosaccharide analysis performed using GC-MS showed the presence of fucose, erythrotetrose, ribose, and glucose as monomers. EPS-DR3A showed excellent emulsifying activity against the tested hydrocarbons and food oils with stable emulsions. Rheological analysis of EPS-DR3A revealed the pseudoplastic behavior. The EPS-DR3A displayed good thermal stability with a degradation temperature of 249 °C and a melting point at 322 °C. Further, it had the ability to scavenge DPPH and nitric oxide free radicals with good total antioxidant activity. The in vitro biocompatibility study of EPS-DR3A showed high degree of biocompatibility with human dermal fibroblast cells at the tested concentrations. Taken together, the findings such as thermostability, emulsifying activity, pseudoplasticity, antioxidant activity, and biocompatibility of EPS-DR3A make this biomolecule an important candidate for a wide range of biomedical applications.

Bio-corrosion impacts on mechanical integrity of ZM21 Mg for orthopaedic implant application processed by equal channel angular pressing

The mechanical integrity of rolled ZM21 Mg was improved by equal channel angular pressing (ECAP) to function as a potential biodegradable bone screw implant. Electron backscattered diffraction (EBSD) revealed deformed grains of 45 µm observed in rolled ZM21 Mg. They were transformed to equiaxed fine grains of 5.4 µm after 4^th pass ECAP. The yield strength of rolled and ECAPed ZM21 Mg alloys were comparable. In contrast, 4^th pass ZM21 Mg exhibited relatively higher elongation when compared to rolled sample. The mechanical properties of rolled and ECAPed ZM21 Mg were dependant on both grain refinement and crystallographic texture. The rolled and 4^th pass ECAPed tensile samples exhibited nonlinear deterioration of mechanical properties when tested after 7, 14, 21 and 28 days immersion in Hank's solution. The evaluation signifies that regardless their processing condition, ZM21 Mg alloys are suitable for surgical areas that requires high mechanical strength. In addition, the 4^th pass ECAP samples were viable to MG-63 cells proving themselves to be promising candidates for future in vivo studies.

Pregnancy Outcomes Post-bariatric Surgery-a Single-Centre Retrospective Study from India

BACKGROUND

Bariatric surgery presently is the best possible intervention for treatment of severe obesity and its related conditions. This study presents retrospective data on the pregnancy outcomes of Indian patients who underwent bariatric surgery before conception.

METHODOLOGY

This is a single-centre retrospective, observational study. Data on demographics, pre-surgery weight, body mass index (BMI), types of bariatric surgery, weight at conception, weight gain during pregnancy, type of delivery and the health of the baby were collected and analysed to study the weight loss pattern and pregnancy outcomes in female patients of childbearing potential.

RESULTS

The study included 34 women of childbearing potential (BMI>30 kg/m²) who underwent bariatric surgery. The study population was followed up from the time of surgery until 1-year post-delivery of the baby. The mean weight gain during the pregnancy was 14.9±5.4 kg. Twenty-three underwent LSCS, and the rest had normal delivery with mean baby weight of 2.5±0.4 kg. Six babies required neonatal intensive care. In our series, only 4 of 35 cohorts that are only 11% had substantial weight retention (range 5-13 kg) at the end of 12 months which is significantly lower than the normal cohorts who did not undergo bariatric surgery.

CONCLUSION

Bariatric surgery improves fertility with safe pregnancy and its outcomes in terms of preeclampsia, eclampsia, gestational diabetes, premature rupture of the membranes (PROM), postpartum haemorrhage (PPH) and puerperal sepsis in women with childbearing potential and safe for offspring in terms of shoulder dystocia, macrosomia, birth asphyxia and perinatal mortality. However, they should be well aware of the risks associated with bariatric surgery especially the mal-absorptive procedures.

Agricultural management practices influence the soil enzyme activity and bacterial community structure in tea plantations

BACKGROUND

The soil quality and health of the tea plantations are dependent on agriculture management practices, and long-term chemical fertilizer use is implicated in soil decline. Hence, several sustainable practices are used to improve and maintain the soil quality. Here, in this study, changes in soil properties, enzymatic activity, and dysbiosis in bacterial community composition were compared using three agricultural management practices, namely conventional (CA), sustainable (SA), and transformational agriculture (TA) in the tea plantation during 2016 and 2017 period. Soil samples at two-months intervals were collected and analyzed.

RESULTS

The results of the enzyme activities revealed that acid phosphatase, arylsulfatase, β-glucosidase, and urease activities differed considerably among the soils representing the three management practices. Combining the redundancy and multiple regression analysis, the change in the arylsulfatase activity was explained by soil pH as a significant predictor in the SA soils. The soil bacterial community was predominated by the phyla Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Bacteroidetes in the soil throughout the sampling period. Higher Alpha diversity scores indicated increased bacterial abundance and diversity in the SA soils. A significant relationship between bacterial richness indices (SOBS, Chao and ACE) and soil pH, K and, P was observed in the SA soils. The diversity indices namely Shannon and Simpson also showed variations, suggesting the shift in the diversity of less abundant and more common species. Furthermore, the agricultural management practices, soil pH fluctuation, and the extractable elements had a greater influence on bacterial structure than that of temporal change.

CONCLUSIONS

Based on the cross-over analysis of the bacterial composition, enzymatic activity, and soil properties, the relationship between bacterial composition and biologically-driven ecological processes can be identified as indicators of sustainability for the tea plantation.

Bioresponsive supramolecular hydrogels for hemostasis, infection control and accelerated dermal wound healing

Injectable, drug-releasing hydrogel scaffolds with multifunctional properties including hemostasis and anti-bacterial activity are essential for successful wound healing; however, designing ideal materials is still challenging. Herein, we demonstrate the fabrication of a biodegradable, temperature-pH dual responsive supramolecular hydrogel (SHG) scaffold based on sodium alginate/poly(N-vinyl caprolactam) (AG/PVCL) through free radical polymerization and the subsequent chemical and ionic cross-linking. A natural therapeutic molecule, tannic acid (TA)-incorporated SHG (AG/PVCL-TA), was also fabricated and its hemostatic and wound healing efficiency were studied. In the AG/PVCL-TA system, TA acts as a therapeutic molecule and also substitutes as an effective gelation binder. Notably, the polyphenol-arm structure and diverse bonding abilities of TA can hold polymer chains through multiple bonding and co-ordinate cross-linking, which were vital in the formation of the mechanically robust AG/PVCL-TA. The SHG formation was successfully balanced by varying the composition of SA, VCL, TA and cross-linkers. The AG/PVCL-TA scaffold was capable of releasing a therapeutic dose of TA in a sustained manner under physiological temperature-pH conditions. AG/PVCL-TA displayed excellent free radical scavenging, anti-inflammatory, anti-bacterial, and cell proliferation activity towards the 3T3 fibroblast cell line. The wound healing performance of AG/PVCL-TA was further confirmed in skin excision wound models, which demonstrated the potential application of AG/PVCL-TA for skin regeneration and rapid wound healing.

Isoeugenol suppresses multiple quorum sensing regulated phenotypes and biofilm formation of Pseudomonas aeruginosa PAO1

The potential strategy to prevent bacterial pathogenicity is disabling quorum sensing circuits with structural mimicking molecules. Here, we analyzed a synthetic molecule isoeugenol, for inhibition of quorum sensing regulated phenotype and biofilm formation. Isoeugenol was an effective inhibitor, i.e., more than 70% of virulence factors were inhibited including pyocyanin, rhamnolipid, exopolysaccharide, swarming motility and biofilm formation. Interestingly, these quorum sensing regulated phenotypes in Pseudomonas aeruginosa PAO1 were inhibited without affecting the planktonic cells. Moreover, the presence of isoeugenol exhibited more than 70% inhibition of biofilm formation through inhibition of the quorum sensing systems. Furthermore, docking studies suggest that isoeugenol bound to the quorum sensor regulators such as LasI, LasR PqsE and SidA with considerable binding interactions. Our results demonstrate the utility of isoeugenol as a blocker of quorum sensing, which will be functioning as an antivirulence compound.

Genome analysis of a halophilic bacterium Halomonas malpeensis YU-PRIM-29T reveals its exopolysaccharide and pigment producing capabilities

Halomonas malpeensis strain YU-PRIM-29T is a yellow pigmented, exopolysaccharide (EPS) producing halophilic bacterium isolated from the coastal region. To understand the biosynthesis pathways involved in the EPS and pigment production, whole genome analysis was performed. The complete genome sequencing and the de novo assembly were carried out using Illumina sequencing and SPAdes genome assembler (ver 3.11.1) respectively followed by detailed genome annotation. The genome consists of 3,607,821 bp distributed in 18 contigs with 3337 protein coding genes and 53% of the annotated CDS are having putative functions. Gene annotation disclosed the presence of genes involved in ABC transporter-dependent pathway of EPS biosynthesis. As the ABC transporter-dependent pathway is also implicated in the capsular polysaccharide (CPS) biosynthesis, we employed extraction protocols for both EPS (from the culture supernatants) and CPS (from the cells) and found that the secreted polysaccharide i.e., EPS was predominant. The EPS showed good emulsifying activities against the petroleum hydrocarbons and its production was dependent on the carbon source supplied. The genome analysis also revealed genes involved in industrially important metabolites such as zeaxanthin pigment, ectoine and polyhydroxyalkanoate (PHA) biosynthesis. To confirm the genome data, we extracted these metabolites from the cultures and successfully identified them. The pigment extracted from the cells showed the distinct UV-Vis spectra having characteristic absorption peak of zeaxanthin (λmax 448 nm) with potent antioxidant activities. The ability of H. malpeensis strain YU-PRIM-29T to produce important biomolecules makes it an industrially important bacterium.

Is weight regaining significant post laparoscopic Roux-en-Y gastric bypass surgery? - A 5-year follow-up study on Indian patients

Background

Laparoscopic Roux-en-Y gastric bypass (RYGB) has been proven to induce significant weight loss and remission of related co-morbidities in patients with morbid obesity. The long-term follow-up data show weight regain or failure to achieve complete remission of type 2 diabetes mellitus (T2DM) in some patients. In this study, we report weight loss patterns and remission of T2DM in patients with morbid obesity during a 5-year follow-up after RYGB.

Objective

The objective was to evaluate outcomes during the follow-up on excess weight loss (EWL) and remission of T2DM after laparoscopic RYGB among Indian patients.

Setting

The study was conducted in a tertiary care hospital, Kerala, India.

Materials and Methods

This is a retrospective study in patients who underwent surgery between 2007 and 2010. The patient demographics, pre- and post-operative body mass index (BMI), co-morbidities and EWL were recorded from the medical records. These data were compared between pre-operative and follow-up intervals till 5 years using statistical approaches.

Results

The study included 157 patients (91 males and 66 females) having a mean pre-operative BMI of 47.91 ± 7.01 kg/m². A significant reduction in the BMI was observed at each follow-up point (P < 0.01) till 5 years after the surgery. The mean percentage of EWL increased from 34.57% ± 12.62% to 71.50% ± 15.41% from 3 months to 5 years after the surgery. Twelve per cent (n = 19) of patients achieved normal BMI (<25 mg/kg²) by 3^rd year after the surgery. However, the remission of T2DM was achieved in >50% of patients within a year of surgery. During the 5^th year, weight regain (1-22 kg) was observed in 36.70% (n = 58) patients, and recurrence of T2DM was observed in two patients.

Conclusions

The long-term durability of RYGB in the study population was satisfactory with significant weight loss and remission of T2DM.

Demineralization of tooth enamel following radiation therapy; An in vitro microstructure and microhardness analysis

Objective

The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel.

Materials and Methods

Synchrotron radiation Xray microcomputed tomography (SRμCT) and microhardness testing were carried out on 8 and 20 tooth samples, respectively. Enamel mineral density was derived from SRμCT technique using ImageJ software. Microhardness samples were subjected to Vickers indentations followed by calculation of microhardness and percentage mineral volume values using respective mathematical measures. Data were analyzed using paired t-test at a significance level of 5%. Qualitative analysis of the enamel microstructure was done with two-dimensional projection images and scanned electron micrographs using μCT and field emission scanning electron microscopy, respectively.

Results

Vickers microhardness and SRμCT techniques showed a decrease in microhardness and an increase in mineral density, respectively, in postirradiated samples. These changes were related to mineral density variation and alteration of hydroxyapatite crystal lattice in enamel surface. Enamel microstructure showed key features such as microporosities and loss of smooth homogeneous surface. These indicate tribological loss and delamination of enamel which might lead to radiation caries.

Conclusions

Tooth surface loss might be a major contributing factor for radiation caries in head-and-neck cancer patients prescribed to radiotherapy. Such direct effects of radiotherapy cause enamel abrasion, delamination, and damage to the dentinoenamel junction. Suitable measures should, therefore, be worked out to protect nontarget oral tissues such as teeth while delivering effective dosages to target regions.

Bacterial cross talk with gut microbiome and its implications: a short review

Human gut microbiota exists in a complicated symbiotic relationship which postulates to impact health and disease conditions on the host. Interestingly, the gut microbiome shows different mechanisms to regulate host physiology and metabolism including cell-to-cell communications. But microbiota imbalance is characterized to change in the host normal functioning and lead to the development and progression of major human diseases. Therefore, the direct cross talk through the microbial metabolites or peptides suggests the evidence of host health and disease. Recent reports highlight the adaptation signals/small molecules promoting microbial colonization which allows modulating immunity of host and leads to pathogen colonization. Moreover, quorum sensing peptides are also evident in the involvement of host disease conditions. Here, we review the current understanding of the gut microbiota cross talk with mammalian cells through metabolites and peptides. These studies are providing insight into the prediction of signature molecules which significantly provide information for the understanding of the interaction for precision medicine applications.

A novel exopolysaccharide from marine bacterium Pantoea sp. YU16-S3 accelerates cutaneous wound healing through Wnt/β-catenin pathway

Natural polysaccharides with versatile properties are the potential candidates for wound healing applications. In this study, an exopolysaccharide, EPS-S3, isolated from a marine bacteria Pantoea sp. YU16-S3 was evaluated for its wound-healing abilities by studying the key molecular mechanisms in vitro and in vivo. Basic characterisation showed EPS-S3 as a heteropolysaccharide with glucose, galactose, N-acetyl galactosamine and glucosamine. The molecular weight of EPS-S3 was estimated to be 1.75 × 10⁵ Da. It showed thermal stability up to 200 °C and shear-thickening non-Newtonian behaviour. It was biocompatible with dermal fibroblasts and keratinocytes and showed cell adhesion and cell proliferation properties. EPS-S3 facilitated cell migration in fibroblasts, induced rapid transition of cell cycle phases and also activated macrophages. In vivo experiments in rats showed the re-epithelialization of injured tissue with increased expression of HB-EGF, FGF, E-cadherin and β-catenin in EPS-S3 treatment. The results indicate that EPS-S3 modulates healing process through Wnt/β-catenin pathway due to its unique characteristics. In conclusion, EPS-S3 biosynthesized by the marine bacterium is a potential biomolecule for cutaneous wound healing applications.

The whole-genome sequence analysis of Enterobacter cloacae strain Ghats1: insights into endophytic lifestyle-associated genomic adaptations

Enterobacter cloacae is normally considered to be an opportunistic human pathogen. Here, we report on the whole-genome sequence of an endophytic E. cloacae, strain "Ghats1", isolated from leaves of the medicinal plant Coscinium fenestratum Gaertn. Functional analysis of the Ghats1 genome revealed an enrichment for genes involved in the uptake and exchange of nutrients, for chemotaxis and for plant colonization. Unexpectedly though, there were no ORFs belonging to the "virulence factors and antibiotic resistance". Moreover, the presence of hydrolytic enzymes and motility functions reveals the characteristics of an endophyte lifestyle of a bacterium that can colonize and adapt to plant environment. These results provide a better understanding of an endophytic lifestyle through plant-microbe interaction, which can be further exploited as a biocontrol agent.

Seven-Year Outcomes of Laproscopic Sleeve Gastectomy in Indian Patients with Different Classes of Obesity

BACKGROUND

The aim of the study was to assess the long-term outcome in terms of weight loss and remission of comorbidities among the patients who had undergone LSG in an Indian setting.

METHODS

This is a retrospective observational study of patients (BMI > 30 kg/m²) who underwent LSG having a minimum 6 months of follow-up data. Based on preoperative BMI, patients were grouped as class 1, 30 < BMI < 35 kg/m²; class 2, 35 < BMI < 40 kg/m²; and class 3, BMI > 40 kg/m². Data on BMI and %EWL between three classes and among genders at different follow-up points for 7 years were compared.

RESULT

Study included 95 patients (mean age of 33.7 ± 11 years), and the preoperative mean BMI was 40.2 ± 5.1 kg/m². At one year of surgery, 85.5% patients achieved > 50%EWL. The highest mean %EWL was found in class 1 (66.19%), followed by class 2 (56.73%) and class 3 (46.59%) at the sixth month follow-up. At the seventh year, %EWLs were 85.11% (class 1), 76.69% (class 2), and 62.98% (class 3) and the mean BMIs were 25.13 ± 3.09 kg/m² (class 1), 26.86 ± 2.12 kg/m² (class 2), and 31.07 ± 3.39 kg/m² (class 3) and were significantly different (p < 0.05). At the last follow-up, though, the males showed slight weight regain; however, there were no statistical differences between the genders (p = 0.065).

CONCLUSION

Outcome from LSG was better in patients with BMI < 40 kg/m² compared to the patients with BMI > 40 kg/m². Remission of obesity-related comorbidities was observed with LSG in all groups and gender did not influence the outcome significantly.

Tetrandrine isolated from Cyclea peltata induces cytotoxicity and apoptosis through ROS and caspase pathways in breast and pancreatic cancer cells

Tetrandrine is a bisbenzylisoquinoline alkaloid known to exhibit anticancer activity against different cancers. In the present study, the cytotoxic effect of tetrandrine isolated from Cyclea peltata on pancreatic (PANC-1) and breast (MDA-MB-231) cancer cells was evaluated in vitro with an attempt to understand the role of tetrandrine on the generation of reactive oxygen species (ROS) and caspase activation. Results demonstrate the dose- and time-dependant cytotoxic effect of tetradrine on both MDA-MB-231 and PANC-1 cells with IC₅₀ values ranging between 51 and 54 μM and 22 and 27 μM for 24 h and 48 h of incubation respectively. In addition, treatment of MDA-MB-231 and PANC-1 cells with tetrandrine showed the shrunken cytoplasm and damaged cell membrane in a dose- and time-dependant manner under the microscope. Also, tetrandrine treatment revealed an elevated levels of reactive oxygen species and increased activities of caspase-8, -9 and -3 confirming the apoptosis of cells through both extrinsic death receptor and intrinsic caspase activation. Therefore, the present study suggests the apoptosis of cells with the activation of caspase pathways mainly intrinsic pathway as a downstream event of tetrandrine-induced ROS generation. Hence, reactive oxygen species-mediated caspase activation pathway may be potentially targeted with the use of tetrandrine to treat breast and pancreatic cancers.

A bioactive exopolysaccharide from marine bacteria Alteromonas sp. PRIM-28 and its role in cell proliferation and wound healing in vitro

Marine bacteria secrete exopolysaccharides (EPS) with unique structural and functional properties and serve as a source of newer bioactive biopolymers. This study reports an EPS produced by a marine bacterium identified as Alteromonas sp. PRIM-28 for its bioactivities. The EPS was characterised using standard methods and tested for its bioactivities using in vitro models. EPS-A28 is an anionic heteropolysaccharide with a molecular weight of 780 kDa and exists as triple helical structure in aqueous solution. Monosaccharide composition is mannuronic acid, glucose and N-acetyl glucosamine repeating units in the ratio 1:3.67:0.93. The FT-IR spectra showed the presence of sulphate, phosphate and uronic acid residues. The thermal analysis showed partial degradation of the EPS-A28 at 190 °C and 40% of residues were stable up to 800 °C. It showed biocompatibility and induced proliferation and migration of dermal fibroblasts (HDF) and keratinocytes. EPS-A28 could increase the S-phase of cell cycle. The proliferative property of the EPS-A28 was established by the increased expression of fibroblast proliferation marker (Ki-67) also its capability of binding to cell surface. It also induced nitric oxide and arginase synthesis in macrophages. These findings suggest that EPS-A28 can be potentially used as a multifunctional bioactive polymer in wound care.

Adaptation and diversification in virulence factors among urinary catheter-associated Pseudomonas aeruginosa isolates

AIM

The aim of this study was to investigate the natural variation in the antibiotic sensitivity, biofilm formation and virulence among Pseudomonas aeruginosa isolated from the catheter-associated urinary tract infection (CAUTI) from a single centre.

METHODS AND RESULTS

Pseudomonas aeruginosa strains were isolated from the patients with CAUTI after obtaining informed consent. These isolates were identified by routine biochemical methods and 16S rRNA gene sequencing. Antibiotic sensitivity and virulence factors were measured using standard protocols. Crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy were used for the biofilm studies. The extent of infectivity of the strains to induce cell lysis was studied in vitro using the Human Embryonic Kidney cells (HEK 293T). Association between virulence factors, biofilm formation and antibiotic resistance among the strains was analysed statistically. Among the 1266 patients admitted during the 2016-2017 period, 98 cases of CAUTI were reported and 18·36% (n = 18) was due to P. aeruginosa infection. Antibiogram showed that 94·4% of isolates were resistant to multiple antibiotics and 73·7% were carbapenem-resistant. All the isolates formed biofilm on different material surfaces with varying intensity (OD₅₈₀ ≥0·20-1·11). The biofilm intensity on silicone-latex material was significantly higher compared to the polystyrene surface (P > 0·05). All the strains were highly virulent and able to cause cell killing of HEK 293T cells with a rate ranging from 69·35 to 100% and showed very low sensitivity to healthy human serum.

CONCLUSIONS

Antibiotic sensitivity and association between the virulence factors and biofilm formation in the P. aeruginosa clinical strains showed complex natural diversity.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates the natural diversity and adaptation in virulence factors, biofilm formation and host-pathogen interaction among catheter-associated P. aeruginosa strains. The findings from the study urge for developing individualized drug strategy for targeting these multidrug-resistant pathogens.

Study on the morphological and biocompatible properties of chitosan grafted silk fibre reinforced PVA films for tissue engineering applications

The current study delineates the preparation of novel chitosan grafted silk fibre reinforced Poly (vinyl alcohol) (PVA) composite films with desirable properties. Although silk fibroin has been extensively used for various biomedical applications, its properties could be further re-tailored for its suitability in the field of regenerative medicine. Chitosan was successfully grafted over silk, via acylation with succinic anhydride and thereby the fibres were incised and used for the preparation of the films. The grafted silk fibre reinforced PVA films were subjected to FTIR studies, microscopic analysis by atomic force microscopy (AFM) and optical microscopy techniques, X-ray diffraction (XRD) analysis and further evaluated for in vitro biocompatibility studies. The composite films demonstrated improved surface roughness with increasing concentration of the fibre and its dispersion in the polymer matrix was observed. Furthermore, in vitro biocompatibility and cellular behaviour such as adhesion and proliferation of mouse fibroblasts as well as astrocyte cells was studied and the results showed improved proliferative activity, when compared to the pristine PVA films. These results were further supported by the results confirmed by MTT assay demonstrating the films to be non-toxic. The efficiency and feasibility of the films to be used for tissue engineering, was further evaluated by haemocompatibility studies using human erythrocytes, thus making them a potential material to be used for biomedical applications.

Halomonas malpeensis sp. nov., isolated from rhizosphere sand of a coastal sand dune plant

A Gram-stain-negative, aerobic, non-endospore-forming organism, isolated from the rhizosphere sand of a coastal sand dune plant was studied for its taxonomic position. On the basis of 16S rRNA gene sequence similarity comparisons, strain YU-PRIM-29^T was grouped within the genus Halomonas and was most closely related to Halomonas johnsoniae (97.5 %). The 16S rRNA gene sequence similarity to other Halomonas species was <97.5 %. Strain YU-PRIM-29^T grew optimally at 28 °C (growth range, 10-36 °C), at a pH of 7-9 (growth range, pH 5.5-12.0) and in the presence of 0.5 to 5 % (w/v) NaCl (growth up to 20 % NaCl). The fatty acid profile from whole-cell hydrolysates supported the allocation of the strain to the genus Halomonas. The fatty acids C18 : 1ω7c and C16 : 0 were found as major compounds, followed by the hydroxylated fatty acid C12 : 0 3-OH. The quinone system consisted predominantly of ubiquinone Q-9. The polar lipid profile was composed of the major lipids diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. In the polyamine pattern, spermidine was the predominant compound. The DNA G+C content was 64.8 mol%. In addition, the results of physiological and biochemical tests also allowed phenotypic differentiation of strain YU-PRIM-29^T from its closest-related species. Hence, YU-PRIM-29^T represents a new species of the genus Halomonas, for which we propose the name Halomonas malpeensis sp. nov., with YU-PRIM-29^T (=LMG 28855^T=CCM 8737^T) as the type strain.

Functional and cell proliferative properties of an exopolysaccharide produced by Nitratireductor sp. PRIM-31

Exopolysaccharides (EPS) produced by bacteria are important source of natural biomolecules with therapeutic applications. In this study EPS produced by a strain PRIM-31 isolated from seawater from south west coast of India identified by 16S rRNA gene sequencing as Nitratireductor sp. was investigated for its biotechnological applications. The isolate produced 650 mg L(-1) EPS under optimum growth conditions. The purified EPS contained 58.3% carbohydrates with 7.08% uronic acid containing sugars, functional groups such as sulfate (2.68%) and trace amounts of proteins (0.65%). Molecular weight of the EPS was 90 kDa and monosaccharide composition was arabinose, glucose, xylose, glucuronic acid and galactose (6.6: 3.5: 2.1: 1.3: 1). The EPS displayed antioxidant activity in terms of total antioxidant capacity, ferric reducing power, scavenging of DPPH (IC50 390 μg mL(-1)) and superoxide radicals (IC50 340 μg mL(-1)). Cell proliferative activity of the EPS was evidenced by significant improvement in human dermal fibroblast (HDF) proliferation compared to control. Further, significant improvement (41%) in HDF cell migration was observed in in vitro scratch assay with EPS treatment. The EPS also showed antiproliferative activity against glioblastoma cells with an IC50 of 234.04 μg mL(-1). These functional properties of the EPS prospect its biotechnological applications.

Versatile properties of an exopolysaccharide R-PS18 produced by Rhizobium sp. PRIM-18

Exopolysaccharides (EPS) produced by bacteria have attracted scientific and industrial attention due to their multifunctional properties and relatively easier production. In this study, an EPS viz., R-PS18 produced by Rhizobium sp. PRIM-18 was characterized and its functional properties were assessed. Cell proliferative and in vitro wound healing activities of the EPS were established using human dermal fibroblast (HDF) cells. The isolate produced 2.1 g L(-1) purified EPS (molecular weight 9.33×10(6) Da) comprising of glucose, galactose, and mannose (6.1:1.8:1). Viscosity of 0.25% solution was 23.4 mPa s (shear rate 75 s(-1)) and it showed pseudoplastic and thixotropic behavior. High emulsification, iron chelation, and superoxide scavenging abilities were also observed. Significant increase in HDF cell proliferation and wound healing in vitro was achieved by R-PS18 treatment. Sulfation of R-PS18 significantly enhanced the cell proliferative and wound healing activities. In conclusion, these findings indicate potential applications of R-PS18.

Carbon nanotube-reinforced hydroxyapatite composite and their interaction with human osteoblast in vitro

As a bone mineral component, hydroxyapatite (HA) has been an attractive bioceramic for the reconstruction of hard tissues. However, its poor mechanical properties, including low fracture toughness and tensile strength, have been a substantial challenge to the application of HA for the replacement of load-bearing and/or large bone defects. In this study, HA is reinforced with high-purity and well-functionalized multiwalled carbon nanotubes (MWCNTs; >99 wt%) having an average diameter of 15 nm and length from 10 to 20 μm. The cellular response of these functionalized CNTs and its composites were examined in human osteoblast sarcoma cell lines. Calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) and diammonium hydrogen phosphate ((NH4)2HPO4) were used to synthesize HA in situ. MWCNTs were functionalized by heating at 100°C in 3:1 ratio of sulfuric acid and nitric acid for 60 min with stirring and dispersed in sodium dodecyl benzene sulfonate by sonication. HA particles were produced in MWCNTs solution by adding Ca(NO3)2·4H2O and (NH4)2HPO4 under vigorously stirring conditions. The composite was dried and washed in distilled water followed by heat treatment at 250°C to obtain CNT-HA powder. Physiochemical characterization of the composite material was carried out using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectrometer, and X-ray diffractometer. Furthermore, this study investigates the cytotoxic effects of functionalized-MWCNTs (f-MWCNTs) and its composites with HA in human osteoblast sarcoma cell lines. Human osteoblast cells were exposed with different concentrations of f-MWCNTs and its composite with HA. The interactions of f-MWCNT and MWCNT-HA composites were analyzed by 3-(4,5–dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The results indicate no detrimental effect on survival or mitochondrial activity of the osteoblast cells. Cell viability decreased with an increase in CNT concentration indicating that MWCNTs and its composite can be cytotoxic at higher dosages. This result provides further evidence that the bionano interface can be developed for CNT-reinforced HA composites for load-bearing bone implants, drug delivery, and tissue engineering.

Anti-quorum sensing activity of flavonoid-rich fraction from Centella asiatica L. against Pseudomonas aeruginosa PAO1

BACKGROUND/PURPOSE

Inhibition of quorum sensing (QS), a cell-density dependent regulation of gene expression in bacteria by autoinducers is an attractive strategy for the development of antipathogenic agents.

METHODS

In this study, the anti-QS activity of the ethanolic extract of the traditional herb Centella asiatica was investigated by the biosensor bioassay using Chromobacterium violaceum CV026. The effect of ethyl acetate fraction (CEA) from the bioassay-guided fractionation of ethanol extract on QS-regulated violacein production in C. violaceum ATCC12472 and pyocyanin production, proteolytic and elastolytic activities, swarming motility, and biofilm formation in Pseudomonas aeruginosa PAO1 were evaluated. Possible mechanism of QS-inhibitory action on autoinducer activity was determined by measuring the acyl homoserine lactone using C. violaceum ATCC31532. Anti-QS compounds in the CEA fraction were identified using thin layer chromatography biosensor overlay assay.

RESULTS

Ethanol extract of C. asiatica showed QS inhibition in C. violaceum CV026. Bioassay-guided fractionation of ethanol extract revealed that CEA was four times more active than the ethanol extract. CEA, at 400 μg/mL, completely inhibited violacein production in C. violaceum ATCC12472 without significantly affecting growth. CEA also showed inhibition of QS-regulated phenotypes, namely, pyocyanin production, elastolytic and proteolytic activities, swarming motility, and biofilm formation in P. aeruginosa PAO1 in a concentration-dependent manner. Thin layer chromatography of CEA with biosensor overlay showed anti-QS spot with an Rf value that corresponded with that of standard kaempferol.

CONCLUSION

The anti-QS nature of C. asiatica herb can be further exploited for the formulation of drugs targeting bacterial infections where pathogenicity is mediated through QS.

Zeaxanthin biosynthesis by members of the genus Muricauda

Zeaxanthin, a C40xanthophyll carotenoid, has potential biological applications in nutrition and human health. In this study we characterized carotenoid composition in 5 taxonomically related marine bacterial isolates from the genus Muricauda. The pigment was characterized using high performance liquid chromatography (HPLC) and mass spectrometry, which confirmed the presence of all-trans-zeaxanthin. Muricauda strains produced zeaxanthin as a predominant carotenoid. M. flavescens JCM 11812(T) produced highest yield (4.4 +/- 0.2 mg L(-1)) when cultured on marine broth at 32 degrees C for 72 h. This is the first report on the presence of zeaxanthin among the majority of species from the genus Muricauda.

Description of Noviherbaspirillum malthae gen. nov., sp. nov., isolated from an oil-contaminated soil, and proposal to reclassify Herbaspirillum soli, Herbaspirillum aurantiacum, Herbaspirillum canariense and Herbaspirillum psychrotolerans as Noviherbaspirillum soli comb. nov., Noviherbaspirillum aurantiacum comb. nov., Noviherbaspirillum canariense comb. nov. and Noviherbaspirillum psychrotolerans comb. nov. based on polyphasic analysis

An aerobic, Gram-negative, rod-shaped bacterium with polar flagella, strain CC-AFH3(T), was isolated from an oil-contaminated site located in Kaohsiung county, Taiwan. Strain CC-AFH3(T) grew at 20-40 °C, pH 5.0-10.0 and <2 % (w/v) NaCl. 16S rRNA gene sequence analysis indicated that strain CC-AFH3(T) showed the greatest degree of similarity to Herbaspirillum soli SUEMI10(T) (96.5 %), H. aurantiacum SUEMI08(T) (96.3 %), H. canariense SUEMI03(T) (96.0 %), H. psychrotolerans PB1(T) (95.4 %) and members of other Herbaspirillum species (94.1-95.2 %), and lower similarity to members of other genera (<94 %). Phylogenetic analyses also positioned the novel strain in the genus Herbaspirillum as an independent lineage. The major fatty acids in strain CC-AFH3(T) were C10 : 0 3-OH, C12 : 0, C14 : 0 2-OH, C16 : 0, iso-C15 : 0 3-OH, C17 : 0 cyclo, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. The major polar lipids of strain CC-AFH3(T) were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine. The predominant quinone was ubiquinone 8 (Q-8) and the DNA G+C content was 63.4 mol%. On the basis of 16S rRNA gene sequence analysis in combination with physiological and chemotaxonomic data, strain CC-AFH3(T) represents a novel species in a new genus, for which we propose the name Noviherbaspirillum malthae gen. nov., sp. nov.; the type strain of Noviherbaspirillum malthae is CC-AFH3(T) ( = BCRC 80516(T) = JCM 18414(T)). We also propose the reclassification of Herbaspirillum soli, Herbaspirillum aurantiacum, Herbaspirillum canariense and 'Herbaspirillum psychrotolerans' as Noviherbaspirillum soli comb. nov. (type strain SUEMI10(T) = LMG 26149(T) = CECT 7840(T)), Noviherbaspirillum aurantiacum comb. nov. (type strain SUEMI08(T) = LMG 26150(T) = CECT 7839(T)), Noviherbaspirillum canariense comb. nov. (type strain SUEMI03(T) = LMG 26151(T) = CECT 7838(T)) and Noviherbaspirillum psychrotolerans comb. nov. (type strain PB1(T) = DSM 26001(T) = LMG 27282(T)), respectively. An emended description of Herbaspirillum seropedicae is also presented.

Hydrolysis of acid and alkali presoaked lignocellulosic biomass exposed to electron beam irradiation

In this study, synergetic effect of mild acid and alkali with electron beam irradiation (EBI) on the enzymatic hydrolysis of a selected grass biomass was assessed. Biomass samples prepared by soaking with 1% H2SO4, or 1% NaOH, were exposed to 75 and 150 kGy of EBI. Water presoaked biomass was used as control. Hydrolysis of pretreated samples was carried out using cellulase (15 FPU/g biomass) for 120 h. Structural changes were studied by FTIR and XRD analyses. Reducing sugar and glucose yields from enzymatic hydrolysis were significantly higher in acid and alkali presoaked EBI exposed samples. Theoretical glucose yield showed 40% increase from control in alkali presoaked EBI exposed (150 kGy) samples. Removal of hemicellulose, decreased crystallinity and structural changes were major factors for the combined treatment effect favoring the hydrolysis.

Bhargavaea ullalensis sp. nov., isolated from coastal sand

A Gram-positive-staining, aerobic, non-endospore-forming bacterium, isolated from Ullal coastal sand, Mangalore, Karnataka, India, on marine agar 2216, was studied in detail for its taxonomic position. Based on 16S rRNA gene sequence similarity comparisons, strain ZMA 19(T) was grouped into the genus Bhargavaea with high 16S rRNA gene sequence similarities to all currently described species of the genus Bhargavaea, Bhargavaea cecembensis (99.3 %), Bhargavaea beijingensis (98.8 %) and Bhargavaea ginsengi (98.6 %). GyrB amino acid sequence-based analysis supported the phylogenetic position and also distinguished strain ZMA 19(T) from the three other species of the genus Bhargavaea. Amino acid sequence similarities were only 85.6 to 89.5 % between strain ZMA 19(T) and the type strains of members of the genus Bhargavaea, which shared higher similarities among each other (93.0 to 96.2 %). The chemotaxonomic characterization supported the allocation of the novel strain to the genus Bhargavaea. The major menaquinone was MK-8. The polar lipid profile contained predominantly diphosphatidylglycerol and moderate amounts of phosphatidylglycerol. The diagnostic peptidoglycan diamino acid was lysine and the polyamine pattern contained spermidine and spermine. The major fatty acids were iso- and anteiso-branched fatty acids. DNA-DNA hybridization with the types strains Bhargavaea cecembensis LMG 24411(T), Bhargavaea beijingensis DSM 19037(T) and Bhargavaea ginsengi DSM 19038(T) resulted in values (reciprocal values in parentheses) of 26 % (29 %), 18 % (15 %) and 21 % (12 %), respectively. The results of physiological and biochemical tests allowed phenotypic differentiation of strain ZMA 19(T) from all other species of the genus Bhargavaea. Thus, ZMA 19(T) represents a novel species of this genus, for which the name Bhargavaea ullalensis sp. nov. is proposed, with ZMA 19(T) ( = LMG 27071(T) = CCM 8429(T)) as the type strain.

Stappia taiwanensis sp. nov., isolated from a coastal thermal spring

A beige-coloured, Gram-stain-negative, aerobic, non-motile moderately thermotolerant, rod-shaped organism, strain CC-SPIO-10-1(T), was isolated from a coastal hot spring of Green Island (Lutao), located off Taituang, Taiwan, on Marine Agar 2216. Based on 16S rRNA gene sequence analysis, this organism was grouped into the genus Stappia, showing 98.3 % sequence similarity to Stappia indica B106(T) and 98.2 % gene sequence similarity to Stappia stellulata IAM 12621(T). Ubiquinone Q-10 was the major respiratory quinone and C18 : 1ω7c and C18 : 1ω7c 11-methyl were detected as the major fatty acids. The hydroxylated fatty acid C18 : 0 3-OH was detected as well. Predominant polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, unidentified aminolipid AL1 and unidentified phospholipid PL1. Minor amounts of several unidentified lipids (PL2 and L1-L7) were present as well. The polyamine pattern contained the major compounds spermidine and spermine. Strain CC-SPIO-10-1(T) could be differentiated from the type strains of S. stellulata and S. indica by a set of biochemical tests. On the basis of the 16S rRNA gene sequence analysis and the chemotaxonomic and physiological data, it is concluded that strain CC-SPIO-10(T) represents a novel species of the genus Stappia for which the name Stappia taiwanensis sp. nov. is proposed. The type strain is CC-SPIO-10 (T) ( = CCUG 59208(T) = LMG 25538 (T) = CCM 7757(T)).

Paracoccus rhizosphaerae sp. nov., isolated from the rhizosphere of the plant Crossostephium chinense (L.) Makino (Seremban)

A Gram-negative, coccoid-shaped bacterium, strain CC-CCM15-8(T), was isolated from a rhizosphere soil sample of the plant Crossostephium chinense (L.) Makino (Seremban) from Budai Township, Chiayi County, Taiwan. 16S rRNA gene sequence analysis clearly allocated strain CC-CCM15-8(T) to the Paracoccus cluster, showing highest similarities to the type strains of 'Paracoccus beibuensis' (98.8%), Paracoccus homiensis (97.6%), Paracoccus aestuarii (97.7%) and Paracoccus zeaxanthinifaciens (97.7%). The fatty acid profile, comprising C(18:1)ω7c as the major component and C(10:0) 3-OH as the characteristic hydroxylated fatty acid, supported the placement of strain CC-CCM15-8(T) within the genus Paracoccus. The polyamine pattern consisted of putrescine and spermidine as major components. Ubiqinone Q-10 was the major quinone type (95%); ubiquinone Q-9 was also detected (5%). The complex polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, and unidentified phospholipids, lipids and glycolipids. Levels of DNA-DNA relatedness between strain CC-CCM15-8(T) and 'P. beibuensis' LMG 25871(T), P. aestuarii DSM 19484(T), P. zeaxanthinifaciens LMG 21993(T) and P. homiensis KACC 11518(T) were 24.9% (34.8%, reciprocal analysis), 15.7% (17.5%), 17.7% (23.4%) and 16.0% (25.4%), respectively. Physiological and biochemical test results allowed the phenotypic differentiation of strain CC-CCM15-8(T) from its closest relatives in the genus Paracoccus. Based on the data presented, it is concluded that strain CC-CCM15-8(T) represents a novel species of the genus Paracoccus, for which the name Paracoccus rhizosphaerae sp. nov. is proposed. The type strain is CC-CCM15-8(T) (=LMG 26205(T)=CCM 7904(T)).

Microbulbifer taiwanensis sp. nov., isolated from coastal soil

A Gram-negative, non-spore-forming rod (CC-LN1-12(T)) was isolated from coastal soil samples of Lutao Island (Green Island), Taiwan, and its taxonomic position was studied. 16S rRNA gene sequence analysis showed that isolate CC-LN1-12(T) was grouped into the Microbulbifer cluster, with the highest similarities to Microbulbifer okinawensis ABABA23(T) (97.9 %), Microbulbifer maritimus TF-17(T) (97.7 %) and Microbulbifer donghaiensis CN85(T) (97.7 %), similarities to all other species of the genus Microbulbifer were lower than 96.8 %. The polyamine pattern contained the major compounds spermidine and cadaverine. The fatty acid profile, comprising the major fatty acids iso-C(15 : 0), iso-C(17 : 1)ω9c, C(18 : 1)ω7c and iso-C(11 : 0) 3-OH as the major hydroxylated fatty acid, supported the affiliation of strain CC-LN1-12(T) to the genus Microbulbifer. DNA-DNA hybridizations between strain CC-LN1-12(T) and Microbulbifer okinawensis ABABA23(T), M. donghaiensis CN85(T) and M. maritimus JCM 12187(T) resulted in relatedness values of 21.5 % (14.3 %, reciprocal analysis), 35.9 % (48.5 %, reciprocal analysis) and 48.1 % (52.1 %, reciprocal analysis), respectively. From these data, as well as from physiological and biochemical tests, strain CC-LN1-12(T) could be clearly differentiated from the most closely related species of the genus Microbulbifer. It is concluded that strain CC-LN1-12(T) represents a novel species, for which the name Microbulbifer taiwanensis sp. nov. is proposed. The type strain is CC-LN1-12(T) ( = LMG 26125(T) = CCM 7856(T)).

Supercritical carbon dioxide micronization of zeaxanthin from moderately thermophilic bacteria Muricauda lutaonensis CC-HSB-11T

Moderately thermophilic bacterial strain CC-HSB-11(T) (Muricauda lutaonensis), which was described recently from a coastal hot spring of Green Island, Taiwan, has been identified to produce zeaxanthin as a predominant xanthophyll by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cell culture in bioreactor produced 3.12 ± 0.18 mg zeaxanthin L(-1) of culture. Micronization of zeaxanthin was achieved through supercritical carbon dioxide antisolvent precipitation method. Yield of zeaxanthin after the process was 53.4%. Dynamic light scattering assay determined the polydisperse existence of micronized particles of size 3 nm to 2 μm. Field emission scanning electron microscopy revealed distinct morphology and size distribution heterogeneity of particles. Integrity of zeaxanthin after the antisolvent process was assessed by LC-MS/MS. The technique capitalizes on the inherent ability of CC-HSB-11(T) to synthesize zeaxanthin and the work demonstrated feasibility of antisolvent precipitation method to produce microparticles exploiting a bacterial strain.

Virgibacillus soli sp. nov., isolated from mountain soil

A Gram-positive bacterium (strain CC-YMP-6(T)) was isolated from soil samples collected from Yang-Ming Mountain, Taiwan. On the basis of 16S rRNA gene sequence analysis, strain CC-YMP-6(T) clearly belonged to the genus Virgibacillus and was most closely related to the type strains of Virgibacillus halophilus (96.2 % similarity) and Virgibacillus kekensis (96.3 %). The predominant isoprenoid quinone was menaquinone MK-7 and the polar lipid profile was composed of the major components diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one unidentified phospholipid plus moderate amounts of two unidentified aminophospholipids and a phospholipid. The polyamine pattern comprised spermidine as the single major component with spermine and putrescine present in minor amounts. The major fatty acids of strain CC-YMP-6(T) were iso-C(15 : 0) and anteiso-C(15 : 0). The results of physiological and biochemical tests allowed the clear phenotypic differentiation of strain CC-YMP-6(T) from all recognized species of the genus Virgibacillus. Strain CC-YMP-6(T) is therefore considered to represent a novel species of the genus Virgibacillus, for which the name Virgibacillus soli sp. nov. is proposed. The type strain is CC-YMP-6(T) (=DSM 22952(T)=CCM 7714(T)).

Microlunatus soli sp. nov., isolated from soil

A Gram-stain-positive, coccoid, non-endospore-forming actinobacterium (strain CC-12602(T)) was isolated from a spawn used for growing the edible mushroom Agaricus brasiliensis in the laboratory. On the basis of 16S rRNA gene sequence analysis, strain CC-12602(T) was shown to belong to the genus Microlunatus and was related most closely to the type strains of Microlunatus ginsengisoli (96.1 % similarity), M. phosphovorus (95.9 %), M. panaciterrae (95.8 %) and M. aurantiacus (95.5 %). The quinone system comprised menaquinone MK-9(H4) as the major component and the polyamine pattern consisted of spermidine and spermine as major compounds. The predominant polar lipids were phosphatidylglycerol and unknown phospholipid PL3. Moderate amounts of diphosphatidylglycerol, an unknown glycolipid and three unknown phospholipids and minor amounts of an unknown phospholipid and a polar lipid were detected. The peptidoglycan type was A3gamma', based on LL-2,6-diaminopimelic acid with an interpeptide bridge consisting of a single glycine residue and a second glycine residue at position 1 of the peptide subunit. Peptidoglycan structure and major fatty acids (anteiso-C(15 : 0), iso-C(16 : 0) and iso-C(15 : 0)) supported the affiliation of strain CC-12602(T) to the genus Microlunatus. The results of physiological and biochemical tests allowed strain CC-12602(T) to be differentiated phenotypically from recognized Microlunatus species. Strain CC-12602(T) is therefore considered to represent a novel species of the genus Microlunatus, for which the name Microlunatus soli sp. nov. is proposed. The type strain is CC-12602(T) (=DSM 21800(T) =CCM 7685( T)).