Selective Screening Research Articles

Abstract 3501: A genome-wide screen for determinants of radioresistance in head and neck cancer

Abstract Introduction: Head and neck cancer (HNC) is the seventh most common cancer worldwide with over 1 million new cases diagnosed each year. Radioresistance is a major cause of both treatment failure and poor prognosis, with locoregional recurrence after radiotherapy occurring in up to 50% of HNC patients. Despite the discovery of individual genes implicated in the ability of HNC cells to develop radioresistance, a systematic evaluation remains to be undertaken. This project is the first to conduct genome-wide CRISPR screens for regulators of radioresistance in HNC, with the aim to identify phenotype-driving genes and pathways. Experimental Procedures: Genome-wide negative selection screens were conducted on HNC cell lines using the Toronto KnockOut (TKO) CRISPR library. Monoclonal Cas9 cell lines were derived from UT-SCC-42A (42A), FaDu, and PE/CA-PJ41 (clone D2) with Cas9 editing efficiencies >80%. Library-transduced cells were treated with the minimum dose of radiation resulting in cessation of cell growth (10 Gy for 42A and FaDu; 8 Gy for PE/CA-PJ41). Genomic DNA from the resultant radioresistant populations was extracted and sequenced on the Illumina NextSeq 500. MAGeCK analysis of read counts identified gene targets of significantly depleted gRNAs after irradiation. Genes that correlated with overall survival (OS) in the TCGA Pan-Cancer database were selected for further investigation. The top candidate genes in the determination of radioresponse were validated using cell proliferation and clonogenic assays. Effects of loss-of-function on cell migration were assessed using scratch wound and transwell migration assays. Results: 117 putative radioresistance genes were identified in the 42A cell line screen; the top ranked hits were MMP14, CD44, CALR, and HHLA1. RNA expression levels of these genes had a significant correlation with OS of radiation-treated HNC patients in the TCGA Pan-Cancer Atlas. Loss-of-function of the candidate genes was confirmed to increase radiosensitivity through live cell imaging in 42A and PJ41 cells, which were further corroborated with clonogenic assays. Downregulation of at least one gene impaired the migration of 42A and PJ41 cells, suggesting a role in cellular invasion and migration. Conclusion: This study will contribute to a deeper understanding of mechanisms of radioresistance in HNC, which continues to be a leading cause of mortality in HNC patients. Future pathway elucidation through transcriptome analysis and functional characterization may reveal additional therapeutic targets that can improve the outcome for HNC patients treated with radiation. Citation Format: Jacqueline H. Law, Pierre-Antoine Bissey, Isabella Kojundzic, Kenneth W. Yip, Fei-Fei Liu. A genome-wide screen for determinants of radioresistance in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3501.

Assessment of Selective and Universal Screening for Suicide Risk in a Pediatric Emergency Department.

According to National Patient Safety Goal 15.01.01, all individuals being treated or evaluated for behavioral health conditions as their primary reason for care in hospitals and behavioral health care organizations accredited by The Joint Commission should be screened for suicide risk using a validated tool. Existing suicide risk screens have minimal or no high-quality evidence of association with future suicide-related outcomes. To test the association between results of the Ask Suicide-Screening Questions (ASQ) instrument in a pediatric emergency department (ED), implemented through selective and universal screening approaches, and subsequent suicide-related outcomes. In this retrospective cohort study at an urban pediatric ED in the United States, the ASQ was administered to youths aged 8 to 18 years with behavioral and psychiatric presenting problems from March 18, 2013, to December 31, 2016 (selective condition), and then to youths aged 10 to 18 years with medical presenting problems (in addition to those aged 8-18 years with behavioral and psychiatric presenting problems) from January 1, 2017, to December 31, 2018 (universal condition). Positive ASQ screen at baseline ED visit. The main outcomes were subsequent ED visits with suicide-related presenting problems (ie, ideation or attempts) based on electronic health records and death by suicide identified through state medical examiner records. Association with suicide-related outcomes was calculated over the entire study period using survival analyses and at 3-month follow-up for both conditions using relative risk. The complete sample was 15003 youths (7044 47.0%] male; 10209 [68.0%] black; mean [SD] age, 14.5 [3.1] years at baseline). The follow-up for the selective condition was a mean (SD) of 1133.7 (433.3) days; for the universal condition, it was 366.2 (209.2) days. In the selective condition, there were 275 suicide-related ED visits and 3 deaths by suicide. In the universal condition, there were 118 suicide-related ED visits and no deaths during the follow-up period. Adjusting for demographic characteristics and baseline presenting problem, positive ASQ screens were associated with greater risk of suicide-related outcomes among both the universal sample (hazard ratio, 6.8 [95% CI, 4.2-11.1]) and the selective sample (hazard ratio, 4.8 [95% CI, 3.5-6.5]). Positive results of both selective and universal screening for suicide risk in pediatric EDs appear to be associated with subsequent suicidal behavior. Screening may be a particularly effective way to detect suicide risk among those who did not present with ideation or attempt. Future studies should examine the impact of screening in combination with other policies and procedures aimed at reducing suicide risk.Appeared originally in JAMA Netw Open 2019; 2:e1914070.

Thalassemia prevention: Religious and cultural barriers to premarital screening in Bangladesh.

Thalassemia prevention: Religious and cultural barriers to premarital screening in Bangladesh.

Selective sonographic screening for developmental dysplasia of the hip – increasing trends in late diagnosis

There are concerns that selective sonographic screening for developmental dysplasia of the hip (DDH) may be suboptimal. Our aim was to test this hypothesis by identifying trends in presentation and surgical treatment in patients with DDH. This is a retrospective review of children born between 1997-2018 who were treated surgically for DDH at our sub- regional paediatric orthopaedic unit. Demographic data, risk factors, age of diagnosis and surgical treatments were analysed. Late diagnosis was defined as greater than 4 months. 103 children (14 male, 89 female) underwent surgery. 93 hips were operated for dislocation and 21 for dysplasia. 13 patients presented with bilateral hip dislocations. The median age at diagnosis was 10 months (95% CI: 4-15). 62/103 (60.2%) were diagnosed late (after 4 months) and the median age for diagnosis in this group was 18.5 months (95% CI: 16-20.5). Significantly more patients were referred late (p=0.0077). The presence of risk factors (breech presentation or family history) was associated with early diagnosis. Over the duration of our study the operation rate per 1000 live births gradually increased, and on Poisson regression analysis there was a statistically significant increasing trend towards late diagnosis in recent years (p=0.0237), which necessitated more aggressive surgical management. In the UK, the current selective sonographic screening programme for DDH has shown a deterioration over the years of this study and this questions its current effectiveness. It appears that the majority of irreducible hip dislocations are diagnosed late, with an increased need for surgical management.

Application of SERS Nanoparticles for Imaging for Fast, Sensitive and Selective Cancer Screening: A Review

Application of SERS Nanoparticles for Imaging for Fast, Sensitive and Selective Cancer Screening: A Review

Rapid and selective screening of organic peroxide explosives using acid-hydrolysis induced chemiluminescence

Organic peroxide explosives (OPEs) are unstable, non-military, contemporary security threats often found in improvised explosive devices. Chemiluminescence (CL) can be used to detect OPEs, via radical formation consisting of peroxide moieties (-O-O-) under acidic conditions. However, selectivity for specific OPEs is hampered by the ubiquitous background of H2O2. Herein, we report the differentiation of hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP), and methyl ethyl ketone peroxide (MEKP) by specific flow injection analysis–CL (FIA-CL) signal profiles, after H2SO4 treatment. The radical degradation pathway of each structure, and its corresponding FIA-CL profile, was explored using mass spectrometry to reveal the rapid loss of -O-O- from TATP and HMTD structures, while MEKP formed CL signal-sustaining oligomers, as opposed to the immediate attenuation of H2O2. The CL response for OPEs in an aqueous media, measured via the described FIA-CL method, enabled ultra-trace limits of detection down to 0.40 μM for MEKP, 0.43 μM for HMTD, and 0.40 μM for TATP (combined linear range 1–83 μM with 95% confidence limit, n = 12). Expanded uncertainties of measurement (UM) of MEKP = ±0.98, HMTD = ±1.03, and TATP = ±1.1 (UM included probabilities of false positive and false negative as well as standard deviations of % recoveries and limit of detections of OPEs). Direct aqueous sample introduction via FIA-CL thus offers the prospect of rapid and selective screening of OPEs in security-heightened settings (e.g., airports), averting false positives from more ubiquitous H2O2.

Competency-Based Medical Education in a Norm-Referenced World: A Root Cause Analysis of Challenges to the Competency-Based Paradigm in Medical School.

Competency-based medical education (CBME) requires a criterion-referenced approach to assessment. However, despite best efforts to advance CBME, there remains an implicit, and at times, explicit, demand for norm-referencing, particularly at the junction of undergraduate medical education (UME) and graduate medical education (GME). In this manuscript, the authors perform a root cause analysis to determine the underlying reasons for continued norm-referencing in the context of the movement toward CBME. The root cause analysis consisted of 2 processes: (1) identification of potential causes and effects organized into a fishbone diagram and (2) identification of the 5 whys. The fishbone diagram identified 2 primary drivers: the false notion that measures such as grades are truly objective and the importance of different incentives for different key constituents. From these drivers, the importance of norm-referencing for residency selection was identified as a critical component. Exploration of the 5 whys further detailed the reasons for continuation of norm-referenced grading to facilitate selection, including the need for efficient screening in residency selection, dependence upon rank-order lists, perception that there is a best outcome to the match, lack of trust between residency programs and medical schools, and inadequate resources to support progression of trainees. Based on these findings, the authors argue that the implied purpose of assessment in UME is primarily stratification for residency selection. Because stratification requires comparison, a norm-referenced approach is needed. To advance CBME, the authors recommend reconsideration of the approach to assessment in UME to maintain the purpose of selection while also advancing the purpose of rendering a competency decision. Changing the approach will require a collaboration between national organizations, accrediting bodies, GME programs, UME programs, students, and patients/societies. Details are provided regarding the specific approaches required of each key constituent group.

Isolation and characterization of fungi and bacteria able to grow on media containing gasoline and diesel fuel

Petroleum products are significant environmental pollutants. This study aimed to isolate microorganisms able to grow on media containing gasoline and diesel fuel. Microorganisms were isolated from soils sampled near gasoline and diesel pumps. Bacterial isolates were characterized and tested on media containing concentrations ranging from 10 to 100 % gasoline and diesel fuel and combinations of both 50/50 % and 25/25/50 % (gasoline/ diesel/ Mueller Hinton broth). Results showed that microbial isolates belong to the genera Pseudomonas, Bacillus, Staphylococcus, Micrococcus, Flavobacterium, Actinobacteria, Penicillium, Hansfordia and Alternaria. Pseudomonas spp. and Bacillus spp. showed the ability to grow on both products up to the concentration of 80 %. However, no growth was noticed above that concentration and on both mixtures. Throughout this study, it has been shown that using a selective screening method for microorganisms able to grow on pollutants can present a significant advantage for bioremediation. Keywords: Pollution; gasoline; diesel; microorganisms.

Selective fundus screening for high-risk newborns: a realistic move in the Chinese mainland

Owing to the popularization of fundus screening for high-risk prematurity promoted by the state, the prevention and treatment of retinopathy of prematurity (ROP) in China has achieved remarkable results in recent years. Accordingly, the applicable population scope for newborn fundus screening is under heated discussion. Is it better to screen for all neonates or selective high-risk newborns, who meet the national ROP guidelines, have a history of familial or/and hereditary eye diseases or a systemic disease related to the eye after birth, or show an abnormal eye appearance or suspicious eye diseases in the primary care examination? Despite the advantages of general screening in detecting and treating some malignant eye diseases in a timely manner, the conditions for carrying out general newborn screening are not mature, and there are certain risks in the fundus examination of children. This article points out that the rational use of existing scarce medical resources to carry out selective fundus screening for newborns with high risks of eye diseases is practical in clinical work.

A drug repurposing approach for individualized cancer therapy based on transcriptome sequencing and virtual drug screening

RNA-sequencing has been proposed as a valuable technique to develop individualized therapy concepts for cancer patients based on their tumor-specific mutational profiles. Here, we aimed to identify drugs and inhibitors in an individualized therapy-based drug repurposing approach focusing on missense mutations for 35 biopsies of cancer patients. The missense mutations belonged to 9 categories (ABC transporter, apoptosis, angiogenesis, cell cycle, DNA damage, kinase, protease, transcription factor, tumor suppressor). The highest percentages of missense mutations were observed in transcription factor genes. The mutational profiles of all 35 tumors were subjected to hierarchical heatmap clustering. All 7 leukemia biopsies clustered together and were separated from solid tumors. Based on these individual mutation profiles, two strategies for the identification of possible drug candidates were applied: Firstly, virtual screening of FDA-approved drugs based on the protein structures carrying particular missense mutations. Secondly, we mined the Drug Gene Interaction (DGI) database (https://www.dgidb.org/) to identify approved or experimental inhibitors for missense mutated proteins in our dataset of 35 tumors. In conclusion, our approach based on virtual drug screening of FDA-approved drugs and DGI-based inhibitor selection may provide new, individual treatment options for patients with otherwise refractory tumors that do not respond anymore to standard chemotherapy.

Moroccan Experience of Targeted Screening for Inborn Errors of Metabolism by Tandem Mass Spectrometry.

Expanded newborn screening using tandem mass spectrometry (MS/MS) for inborn errors of metabolism (IEM), such as organic acidemias (OAs), fatty acid oxidation disorders (FAODs), and amino acid disorders (AAs), is increasingly popular but has not yet been introduced in Africa. With this study, we aim to establish the disease spectrum and frequency of inborn errors of OAs, FAODs, and AAs in Morocco. Selective screening was performed among infants and children suspected to be affected with IEM between 2016 and 2021. Amino acids and acylcarnitines spotted on filter paper were analyzed using MS/MS. Out of 1178 patients with a clinical suspicion, 137 (11.62%) were diagnosed with IEM, of which 121 (88.3%) patients suffered from amino acids disorders, 11 (8%) were affected by FAOD, and 5 (3.7%) by an OA. This study shows that various types of IEM are also present in Morocco. Furthermore, MS/MS is an indispensable tool for early diagnosis and management of this group of disorders.

Restless legs syndrome in DNAJC12 deficiency.

Restless legs syndrome (RLS) is characterized by an unpleasant or painful sensation generally localized to lower limbs and relieved by movement. Its pathogenesis is hypothesized to involve the dopaminergic system, also in the light of the response of RLS to ex adiuvantibus treatment with dopamine agonists. DNAJC12 deficiency is a recently identified inherited metabolic disease coupling hyperphenylalaninemia to deficient dopaminergic and serotoninergic neurotransmission, due to the combined impairment of the three aromatic amino acids' (i.e., phenylalanine, tyrosine, and tryptophan) hydroxylases. DNAJC12 deficiency was reported in 43 patients so far, presenting with wide spectrum of clinical symptoms. Here, we report RLS as a novel clinical manifestation of DNAJC12 deficiency, occurring in two adults while on treatment with L-dopa at longitudinal follow-up. The adjunct of low-dose pramipexole was effective in both patients to treat RLS. Besides, this treatment also allowed an improvement of dopaminergic homeostasis, as evidenced by clinical amelioration and stabilization of a peripheral short prolactin profile (a tool to indirectly evaluate dopaminergic homeostasis). Besides including RLS as a new treatable clinical manifestation of DNAJC12, these observations may suggest the opportunity of a selective screening for DNAJC12 deficiency in patients with idiopathic RLS.

The Role of Psychosocial Screening in Patient Selection for Spine Surgery: A Review.

The purpose of this review is to provide a brief history of previous attempts at developing patient screening tools and to further examine the definitions of these psychological concepts, relevance to clinical outcomes, and implications for spine surgeons during preoperative patient assessments. A literature review was performed by 2 independent researchers to identify original manuscripts related to spine surgery and novel psychological concepts. The history of presurgical psychology screening was also studied, and definitions of frequently utilized metrics were detailed. Seven manuscripts were identified that utilized psychological metrics for preoperative risk assessments and correlated outcomes with these scores. The metrics most frequently used in the literature included resilience, patient activation, grit, and self-efficacy. Current literature favors resilience and patient activation as important metrics for preoperative patient screening. Available studies demonstrate significant associations between these character traits and patient outcomes. Further research is warranted to investigate the roles of preoperative psychological screening to optimize patient selection in spine surgery. The purpose of this review is to provide clinicians with a reference for available psychosocial screening tools and their relevance to patient selection. This review also serves to guide future research directions given the importance of this topic.

Characterization of perioperative glycemic status and dexamethasone use with associated postoperative complications in glioblastoma patients.

Postoperative morbidity in glioblastoma (GBM) patients can be due to the disease course but can also come from postoperative complications. Our objective was to study the association of dexamethasone use and perioperative hyperglycemia with postoperative complications in GBM patients. A single-center, retrospective cohort study was conducted in patients who underwent surgery for primary GBM from 2014-2018. Patients with perioperative fasting blood glucose (FBG) measurements and adequate follow-up to assess for complications were included. A total of 199 patients were included. More than half (53%) had poor perioperative glycemic control (FBG ≥ 7mM for ≥ 20% perioperative days). Higher dexamethasone dose (≥ 8mg) was associated with higher FBG on postoperative days 2-4 and 5 (p = 0.02,0.05,0.004,0.02, respectively). Poor glycemic control was associated with increased odds of 30-day any complication and 30-day infection on univariate analysis (UVA), and 30-day any complication and increased length of stay (LOS) on multivariate analysis (MVA). Higher average perioperative daily dexamethasone dose was associated with increased odds of 30-day any complication and 30-day infection on MVA. Elevated hemoglobin A1c (HgbA1c, ≥ 6.5%) was associated with increased odds of 30-day any complication, 30-day infection, and LOS on UVA. In a multivariate linear regression model, only the diagnosis of diabetes mellitus predicted perioperative hyperglycemia. Perioperative hyperglycemia, higher average dexamethasone use and elevated preoperative HgbA1c are associated with increased risk of postoperative complications in GBM patients. Avoiding hyperglycemia and limiting dexamethasone use in postoperative period may decrease the risk of complications. Select HgbA1c screening may allow the identification of a group of patients at higher risk of complications.

Clinical prediction rule for identifying older patients with toxigenic clostridioides difficile at the time of hospital admission

BackgroundThis study aimed to develop and validate a clinical prediction rule to screen older patients at risk of being toxigenic Clostridioides difficile carriers at the time of hospital admission.MethodsThis retrospective case-control study was performed at a university-affiliated hospital. Active surveillance using a real-time polymerase chain reaction (PCR) assay for the toxin genes of C. difficile was conducted among older patients (≥ 65 years) upon admission to the Division of Infectious Diseases of our institution. This rule was drawn from a derivative cohort between October 2019 and April 2021 using a multivariable logistic regression model. Clinical predictability was evaluated in the validation cohort between May 2021 and October 2021.ResultsOf 628 PCR screenings for toxigenic C. difficile carriage, 101 (16.1%) yielded positive findings. To establish clinical prediction rules in the derivation cohort, the formula was derived using significant predictors for toxigenic C. difficile carriage at admission, such as septic shock, connective tissue diseases, anemia, recent use of antibiotics, and recent use of proton-pump inhibitors. In the validation cohort, the sensitivity, specificity, and positive and negative predictive values of the prediction rule, based on a cut-off value of ≥ 0.45, were 78.3%, 70.8%, 29.5%, and 95.4%, respectively.ConclusionThis clinical prediction rule for identifying toxigenic C. difficile carriage at admission may facilitate the selective screening of high-risk groups. To implement it in a clinical setting, more patients from other medical institutions need to be prospectively examined.

A comparison of different selective ultrasound screening strategies for developmental dysplasia of the hip.

To analyze whether the addition of risk-based criteria to clinical examination-based selective ultrasound screening would increase the rates of early detected cases of developmental dysplasia of the hip (DDH) and decrease the rate of late detected cases. A systematic review with meta-analysis was performed. The initial search was performed in the PubMed, Scopus, and Web of Science databases in November 2021. The following search terms were used: (hip) AND (ultrasound) AND (luxation or dysplasia) AND (newborn or neonate or congenital). A total of 25 studies were included. In 19 studies, newborns were selected for ultrasound based on both risk factors and clinical examination. In six studies, newborns were selected for ultrasound based on only clinical examination. We did not find evidence indicating that there are differences in the incidence of early- and late-detected DDH, or in the incidence of nonoperatively treated DDH between the risk-based and clinical examination-based groups. The pooled incidence of operatively treated DDH was slightly lower in the risk-based group (0.5 (95% confidence interval (CI) 0.3 to 0.7)) compared with the clinical examination group (0.9 per 1,000 newborns, (95% CI 0.7 to 1.0)). The use of risk factors in conjunction with clinical examination in the selective ultrasound screening of DDH might lead to fewer operatively treated cases of DDH. However, more studies are needed before stronger conclusions can be drawn.

Australian Atherosclerosis Society Position Statement on Lipoprotein(a): Clinical and Implementation Recommendations.

This position statement provides guidance to cardiologists and related specialists on the management of adult patients with elevated lipoprotein(a) [Lp(a)]. Elevated Lp(a) is an independent and causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve disease (CAVD). While circulating Lp(a) levels are largely determined by ancestry, they are also influenced by ethnicity, hormones, renal function, and acute inflammatory events, such that measurement should be done after accounting for these factors. Further, circulating Lp(a) concentrations should be estimated using an apo(a)-isoform independent assay that employs appropriate calibrators and reports the results in molar units (nmol/L). Selective screening strategies of high-risk patients are recommended, but universal screening of the population is currently not advised. Testing for elevated Lp(a) is recommended in all patients with premature ASCVD and those considered to be at intermediate-to-high risk of ASCVD. Elevated Lp(a) should be employed to assess and stratify risk and to enable a decision on initiation or intensification of preventative treatments, such as cholesterol lowering therapy. In adult patients with elevated Lp(a) at intermediate-to-high risk of ASCVD, absolute risk should be reduced by addressing all modifiable behavioural, lifestyle, psychosocial and clinical risk factors, including maximising cholesterol-lowering with statin and ezetimibe and, where appropriate, PCSK9 inhibitors. Apheresis should be considered in patients with progressive ASCVD. New ribonucleic acid (RNA)-based therapies which directly lower Lp(a) are undergoing clinical trials.

Ligand fishing as a tool to screen natural products with anticancer potential.

Cancer is the second leading cause of death in the world and its incidence is expected to increase with the aging of the world's population and globalization of risk factors. Natural products and their derivatives have provided a significant number of approved anticancer drugs and the development of robust and selective screening assays for the identification of lead anticancer natural products are essential in the challenge of developing personalized targeted therapies tailored to the genetic and molecular characteristics of tumors. To this end, a ligand fishing assay is a remarkable tool to rapidly and rigorously screen complex matrices, such as plant extracts, for the isolation and identification of specific ligands that bind to relevant pharmacological targets. In this paper, we review the application of ligand fishing with cancer-related targets to screen natural product extracts for the isolation and identification of selective ligands. We provide critical analysis of the system configurations, targets, and key phytochemical classes related to the field of anticancer research. Based on the data collected, ligand fishing emerges as a robust and powerful screening system for the rapid discovery of new anticancer drugs from natural resources. It is currently an underexplored strategy according to its considerable potential.

Selectivity of Hydroxamate- and Difluoromethyloxadiazole-Based Inhibitors of Histone Deacetylase 6 In Vitro and in Cells.

Histone deacetylase 6 (HDAC6) is a unique member of the HDAC family of enzymes due to its complex domain organization and cytosolic localization. Experimental data point toward the therapeutic use of HDAC6-selective inhibitors (HDAC6is) for use in both neurological and psychiatric disorders. In this article, we provide side-by-side comparisons of hydroxamate-based HDAC6is frequently used in the field and a novel HDAC6 inhibitor containing the difluoromethyl-1,3,4-oxadiazole function as an alternative zinc-binding group (compound 7). In vitro isotype selectivity screening uncovered HDAC10 as a primary off-target for the hydroxamate-based HDAC6is, while compound 7 features exquisite 10,000-fold selectivity over all other HDAC isoforms. Complementary cell-based assays using tubulin acetylation as a surrogate readout revealed approximately 100-fold lower apparent potency for all compounds. Finally, the limited selectivity of a number of these HDAC6is is shown to be linked to cytotoxicity in RPMI-8226 cells. Our results clearly show that off-target effects of HDAC6is must be considered before attributing observed physiological readouts solely to HDAC6 inhibition. Moreover, given their unparalleled specificity, the oxadiazole-based inhibitors would best be employed either as research tools in further probing HDAC6 biology or as leads in the development of truly HDAC6-specific compounds in the treatment of human disease states.

Selective isolation and genomic characterization of biopolymer producer—a novel feature of halophile Brachybacterium paraconglomeratum MTCC 13074

BackgroundBiopolymers like polyhydroxyalkanoates (PHA) are the best natural macromolecules to use as alternative to the synthetic polymers. Many prokaryotes accumulate PHA as cytoplasmic intracellular granules and their accumulation is triggered by starving conditions. The PHAs are ecofriendly and used to create biodegradable plastics. The microbial synthesized PHA had acquired global importance in industrial and biomedical sectors. ResultsTen different bacterial strains were isolated for the screening of PHA producers from the estuarine region of the Bay of Bengal, Suryalanka in Bapatla. A yellowish slimy circular colony known as M4 is actively growing on selective minimal media and was screened for polymeric granules in its cytoplasm using Sudan Black B and confirmed with the fluorescent dye Nile blue A. All of the isolates were biochemically tested and isolate M4 is the most capable of growing at high NaCl concentrations (3.2 percent) and tests positive for catalase, methyl red. The M4 strain revealed clear hydrolysis of gelatin, starch, and casein. The 16S rRNA sequencing revealed that M4 is 99.72% of identity to Brachybacterium paraconglomeratum LMG 19861(T) in BLAST and the obtained strain was assigned with accession no. MTCC 13074 and deposited in NCBI with accession no. MW899045. The chief cellular fatty acids found in M4 were C14:0, C15:0, C16:0, C18:1cis-9, C18:0, iso-C15: 0, iso-C14: 0, anteiso-C17: 0 and C18:1-7. Crotonic acid formation from M4-PHB extract was detected at 235nm in a UV spectrophotometer. Methanolysis was done, and derivatives of polyhydroxybutyric acid (PHB) in the extract were analyzed using GC-MS. Increasing viscosity was seen in the extracts which confirms the presence of polymer in the extracts. Thermogravimetric analysis was studied to determine the thermal profile of the PHB in the extract of M4. ConclusionIn the study, the selective screening and extraction of ecofriendly PHB from M4 strain was highlighted. Brachybacterium paraconglomeratum is a novel strain showed its uniqueness by producing few monomeric derivatives of PHB. The strain was reporting for the first time as PHA producer. B. paraconglomeratum has promising characteristics according to its metabolic profile. In addition, this study also helps to understand the diversity of bacteria isolated from marine sources.