Genome sequence of bacteriophage Janeemi isolated on Arthrobacter globiformis from soil collected in New York.

Janeemi is a bacteriophage that infects Arthrobacter globiformis B-2880, which was isolated from soil collected in New York City. The genome has a length of 43,877 bp and contains 69 predicted genes. Based on gene content similarity to phages in the actinobacteriophage database, Janeemi is assigned to phage cluster AZ1.

Digital wearable insole-based identification of knee arthropathies and gait signatures using machine learning.

Gait is impaired in musculoskeletal conditions, such as knee arthropathy. Gait analysis is used in clinical practice to inform diagnosis and monitor disease progression or intervention response. However, clinical gait analysis relies on subjective visual observation of walking as objective gait analysis has not been possible within clinical settings due to the expensive equipment, large-scale facilities, and highly trained staff required. Relatively low-cost wearable digital insoles may offer a solution to these challenges. In this work, we demonstrate how a digital insole measuring osteoarthritis-specific gait signatures yields similar results to the clinical gait-lab standard. To achieve this, we constructed a machine learning model, trained on force plate data collected in participants with knee arthropathy and controls. This model was highly predictive of force plate data from a validation set (area under the receiver operating characteristics curve [auROC] = 0.86; area under the precision-recall curve [auPR] = 0.90) and of a separate, independent digital insole dataset containing control and knee osteoarthritis subjects (auROC = 0.83; auPR = 0.86). After showing that digital insole-derived gait characteristics are comparable to traditional gait measurements, we next showed that a single stride of raw sensor time-series data could be accurately assigned to each subject, highlighting that individuals using digital insoles can be identified by their gait characteristics. This work provides a framework for a promising alternative to traditional clinical gait analysis methods, adds to the growing body of knowledge regarding wearable technology analytical pipelines, and supports clinical development of at-home gait assessments, with the potential to improve the ease, frequency, and depth of patient monitoring.

The way we walk ­ our 'gait' ­ is a key indicator of health. Gait irregularities like limping, shuffling or a slow pace can be signs of muscle or joint problems. Assessing a patient's gait is therefore an important element in diagnosing these conditions, and in evaluating whether treatments are working. Gait is often assessed via a simple visual inspection, with patients being asked to walk back and forth in a doctor's office. While quick and easy, this approach is highly subjective and therefore imprecise. 'Objective gait analysis' is a more accurate alternative, but it relies on tests being conducted in specialised laboratories with large-scale, expensive equipment operated by highly trained staff. Unfortunately, this means that gait laboratories are not accessible for everyday clinical use. In response, Wipperman et al. aimed to develop a low-cost alternative to the complex equipment used in gait laboratories. To do this, they harnessed wearable sensor technologies ­ devices that can directly measure physiological data while embedded in clothing or attached to the user. Wearable sensors have the advantage of being cheap, easy to use, and able to provide clinically useful information without specially trained staff. Wipperman et al. analysed data from classic gait laboratory devices, as well as 'digital insoles' equipped with sensors that captured foot movements and pressure as participants walked. The analysis first 'trained' on data from gait laboratories (called force plates) and then applied the method to gait measurements obtained from digital insoles worn by either healthy participants or patients with knee problems. Analysis of the pressure data from the insoles confirmed that they could accurately predict which measurements were from healthy individuals, and which were from patients. The gait characteristics detected by the insoles were also comparable to lab-based measurements ­ in other words, the insoles provided similar type and quality of data as a gait laboratory. Further analysis revealed that information from just a single step could reveal additional information about the subject's walking. These results support the use of wearable devices as a simple and relatively inexpensive way to measure gait in everyday clinical practice, without the need for specialised laboratories and visits to the doctor's office. Although the digital insoles will require further analytical and clinical study before they can be widely used, Wipperman et al. hope they will eventually make monitoring muscle and joint conditions easier and more affordable.

A Multi-institutional Analysis of Factors Influencing the Rate of Positive MRI Biopsy Among Women with Early-Stage Breast Cancer.

BACKGROUND: The use of preoperative magnetic resonance imaging (MRI) for early-stage breast cancer (ESBC) is increasing, but its utility in detecting additional malignancy is unclear and delays surgical management (Jatoi and Benson in Future Oncol 9:347-353, 2013. https://doi.org/10.2217/fon.12.186 , Bleicher et al. J Am Coll Surg 209:180-187, 2009. https://doi.org/10.1016/j.jamcollsurg.2009.04.010 , Borowsky et al. J Surg Res 280:114-122, 2022. https://doi.org/10.1016/j.jss.2022.06.066 ). The present study sought to identify ESBC patients most likely to benefit from preoperative MRI by assessing the positive predictive values (PPVs) of ipsilateral and contralateral biopsies. METHODS: A retrospective cohort study included patients with cTis-T2N0-N1 breast cancer from two institutions during 2016-2021. A "positive" biopsy result was defined as additional cancer (PositiveCancer) or cancer with histology often excised (PositiveSurg). The PPV of MRI biopsies was calculated with respect to age, family history, breast density, and histology. Uni- and multivariate logistic regression determined whether combinations of age younger than 50 years, dense breasts, family history, and pure ductal carcinoma in situ (DCIS) histology led to higher biopsy yield. RESULTS: Of the included patients, 447 received preoperative MRI and 131 underwent 149 MRI-guided biopsies (96 ipsilateral, 53 contralateral [18 bilateral]). PositiveCancer for ipsilateral biopsy was 54.2%, and PositiveCancer for contralateral biopsy was 17.0%. PositiveSurg for ipsilateral biopsy was 62.5%, and PositiveSurg for contralateral biopsy was 24.5%. Among the contralateral MRI biopsies, patients younger than 50 years were less likely to have PositiveSurg (odds ratio, 0.02; 95% confidence interval, 0.00-0.84; p = 0.041). The combinations of age, density, family history, and histology did not lead to a higher biopsy yield. CONCLUSION: Historically accepted factors for recommending preoperative MRI did not appear to confer a higher MRI biopsy yield. To prevent delays to surgical management, MRI should be carefully selected for individual patients most likely to benefit from additional imaging.

Monoclonal antibodies against GFRα3 are efficacious against evoked hyperalgesic and allodynic responses in mouse join pain models but, one of these, REGN5069, was not effective against pain in a randomized, placebo-controlled clinical trial in patients with osteoarthritis pain.

The artemin-GFRα3 signaling pathway has been implicated in various painful conditions including migraine, cold allodynia, hyperalgesia, inflammatory bone pain, and mouse knees contain GFRα3-immunoreactive nerve endings. We developed high affinity mouse (REGN1967) and human (REGN5069) GFRα3-blocking monoclonal antibodies and, following in vivo evaluations in mouse models of chronic joint pain (osteoarthritic-like and inflammatory), conducted a first-in-human phase 1 pharmacokinetics (PK) and safety trial of REGN5069 (NCT03645746) in healthy volunteers, and a phase 2 randomized placebo-controlled efficacy and safety trial of REGN5069 (NCT03956550) in patients with knee osteoarthritis (OA) pain. In three commonly used mouse models of chronic joint pain (destabilization of the medial meniscus, intra-articular monoiodoacetate, or Complete Freund's Adjuvant), REGN1967 and REGN5069 attenuated evoked behaviors including tactile allodynia and thermal hyperalgesia without discernably impacting joint pathology or inflammation, prompting us to further evaluate REGN5069 in humans. In the phase 1 study in healthy subjects, the safety profiles of single doses of REGN5069 up to 3000 mg (intravenous) or 600 mg (subcutaneous) were comparable to placebo; PK were consistent with a monoclonal antibody exhibiting target-mediated disposition. In the phase 2 study in patients with OA knee pain, two doses of REGN5069 (100 mg or 1000 mg intravenous every 4 weeks) for 8 weeks failed to achieve the 12-week primary and secondary efficacy endpoints relative to placebo. In addition to possible differences in GFRα3 biology between mice and humans, we highlight here differences in experimental parameters that could have contributed to a different profile of efficacy in mouse models versus human OA pain. Additional research is required to more fully evaluate any potential role of GFRα3 in human pain.

Our Experience in Trans Nasal Endoscopic Repair of Anterior Skull Base Defects Reinforced with Multiple Layers of Graft Materials.

Aims: To determine the best technique to repair anterior skull base defects using various grafts. Materials & Methods: This Ambi-directional cohort study was carried out at a tertiary care hospital from May 2019 to October 2021. A total of 17 patients who underwent Endoscopic Repair of Anterior Skull Base Defects using various grafts were included in the study. Detailed history and clinical evaluation followed by Diagnostic Nasal Endoscopy, Biochemical and Radiological investigations were done for all patients with postoperative follow-up for at least 6 months. Results: Most common site of anterior skull base defect in our study group was the posterior wall of the sphenoid sinus. Various graft materials used in our study were fascia lata, thigh fat, Hadad flap, Septal cartilage, nasal septal bone chip, septal mucosal free flap, surgicel and fibrin glue. The most commonly used sequence of graft materials used is the fat(underlay) - fascia lata - fat(overlay). Various complications that occurred were nasal bleeding, residual CSF leak, localized collection of pus in the Septal region, cerebral oedema and Alar trauma. Conclusions: The success of Anterior skull base defect repair depends on watertight Dural closure with multiple layers of grafts to prevent postoperative CSF leak. Although dependent on the Surgeon's preference, usually the sequence of an underlay fat - fascia lata - overlay fat followed by glue/gel foam/Hadad flap works well. Even after discharging the patient, regular follow-up and evaluation ensure that the graft is in situ and there is no CSF leak or other complication.

Daptomycin-Induced Pulmonary Toxicity: A Case Series.

Daptomycin is a bactericidal antibiotic used to treat methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE). Eosinophilic pneumonia is an uncommon but significant adverse effect of daptomycin. We present two patients treated with daptomycin who subsequently developed eosinophilic pneumonia (EP).

COVID-19 Vaccine-Induced Parsonage-Turner Syndrome: A Case Report and Literature Review.

All modern vaccines share the risk of neurological adverse effects. Only a few cases of Parsonage-Turner syndrome (PTS), an uncommon peripheral nerve condition associated with coronavirus disease 2019 (COVID-19) immunization, have been reported to date. We describe a case of COVID-19 vaccine-induced PTS and provide a brief literature review. A 78-year-old male non-smoker with a medical history of coronary artery disease presented with non-exertional, constant chest pain for one hour and new onset of bilateral hand weakness for three days. He had no neurological disease or allergies and denied any recent trauma or infection. Three weeks before the onset of the symptoms, the patient received a second dose of the BNT162b2 COVID-19 vaccine, which was administered 21 days after the first dose. Physical examination was significant for weakness in right-hand grip and wrist flexion. There were no other motor deficits, upper motor neuron signs, bulbar weakness, or sensory deficits. Diagnostic workup for the underlying diabetes mellitus, infections, or other autoimmune diseases was negative. Imaging workup revealed no demyelination, fracture deformity, traumatic subluxation, or compressive myelopathy. Nerve conduction studies, including needle electromyography, showed decreased motor unit recruitment in the bilateral first dorsal interosseous and right deltoid, biceps, and triceps muscles confirming PTS. The patient was treated with 40 mg/day of oral prednisone and occupational therapy to maintain range of motion and activities of daily living. PTS is also known as neuralgic amyotrophy, brachial plexus neuritis, brachial plexopathy, and shoulder-girdle syndrome. It is characterized by asymmetrical, chronic, resistant upper extremity neuropathic pain and neurological defects such as paralysis and paresthesia. There are two different types of PTS: non-hereditary and inherited. The etiology and pathophysiology of PTS are not fully understood. Various aspects such as genetic, environmental, and immunological predisposition may play a role in developing the syndrome. Infections, vaccines, and injuries are typical causes of non-hereditary forms. After the COVID-19 epidemic and the commencement of a global immunization effort, similar instances happened. Presently there is no available test that unequivocally confirms or excludes PTS itself. Electrodiagnostic study and imaging modalities help to rule out other differential diagnoses. Also, there is no specific treatment available; however, it may resolve independently of treatment with supportive care.

Opioid-Sparing Multimodal Analgesia Protocol for Lumpectomy Patients Results in Superior Postoperative Pain Control.

BACKGROUND: We sought to determine if lumpectomy patients who received perioperative opioid-sparing multimodal analgesia reported less pain when compared with those who received traditional opioid-based care. STUDY DESIGN: A prospective cohort of patients undergoing lumpectomy who received an opioid-sparing multimodal analgesia protocol [no opioids group (NOP)] was compared with a large cohort of patients who received traditional care [opioids group (OG)]. In-hospital and discharge opioids were compared using oral morphine equivalents (OMEs). Postoperative day one and week one pain scores were compared using the Kruskal-Wallis test. RESULTS: Overall, 1153 patients underwent lumpectomy: 634 patients received the protocol (NOP), and 519 patients did not (OG). Median pain scores were significantly lower in the NOP cohort when compared with the OG cohort the day after surgery (2 vs. 0, p < 0.001) and the week after surgery (1 vs. 0, p < 0.001). NOP patients were significantly less likely to report severe pain (7-10 on a 10-point scale) the day after surgery compared with OG patients (15.7% vs. 6.9%, p = 0.004). Patients in the NOP cohort were discharged with a median of zero OMEs (range 0-150), while patients in the OG were discharged with a median of 90 OMEs (range 0-360; p < 0.001). CONCLUSION: Implementation of an opioid-sparing multimodal analgesia protocol for lumpectomy patients resulted in superior pain control without a routine opioid prescription. Surgeons can improve their own patients' outcomes while addressing the larger societal issue of the opioid crisis by adopting similar protocols that decrease the quantity of opioids available for diversion.

PET-CT scan-based maximum standardized uptake value as a prognostic predictor in oropharynx squamous cell cancer.

INTRODUCTION: Positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET-CT) is clinically useful and extensively used in initial staging and follow-up of patients with head and neck squamous cell carcinoma (HNSCC). We studied the potential prognostic significance of primary tumor maximum standard uptake value (SUVmax) by 18F-FDG PET-CT in oropharyngeal cancer. METHODS: Sixty patients with early and locally advanced histopathologically proven oropharyngeal squamous cell cancer were staged using FDG PET-CT at diagnosis. All patient received radiation therapy and concurrent chemotherapy (in stage III and IVA disease) and were assessed prospectively for treatment outcome. Groups were created based on stage and cut off for SUVmax. The association of SUVmax of primary tumour and stage with disease-free survival and overall survival was analyzed by univariate and multivariate statistics. RESULTS: In univariate analysis, a primary tumour SUVmax of greater than 13.0 and advanced stage (IVA) predicted inferior disease-free survival (P=0.0241 and 0.0005, respectively) and overall survival (P=0.0510, toward significance and 0.0003, respectively). In proportional hazards analysis, stage was significant only when adjusted for primary SUVmax. CONCLUSION: SUVmax failed to demonstrate predictive significance in oropharyngeal cancer, and an increase in primary tumor uptake is possibly a direct effect of advanced disease and consequently increased metabolic activity and aggressiveness.

Obese Patients Who Receive an Opioid-Sparing Enhanced Recovery After Surgery (ERAS) Protocol are at Increased Risk of Persistent Pain After Breast Surgery.

BACKGROUND: Obese patients are at increased risk of persistent pain and chronic opioid dependence after surgery. We sought to evaluate the impact of an Enhanced Recovery After Surgery (ERAS) protocol in breast surgery patients to determine whether multimodal analgesia was effective for both obese and non-obese patients. METHODS: A prospective cohort of patients undergoing breast surgery who received an opioid-sparing ERAS protocol was compared with patients who did not receive ERAS, including a historical cohort. Pain scores were compared with respect to body mass index (BMI). Obesity was defined as BMI ≥ 30, and moderate to severe pain was defined as 4-10 of a 10-point scale. Postoperative day one and week one pain scores were compared using the Kruskal-Wallis test. RESULTS: A combined contemporary and historical cohort of 1353 patients underwent lumpectomy and mastectomy without reconstruction. The present analysis comprises 622 patients with pain scores who did and did not receive ERAS between 2015 and 2018. The two groups were demographically similar. The day after surgery, those who received ERAS reported lower rates of moderate to severe pain, regardless of BMI (obese: 46.3% vs. 21.8%, p < 0.001; non-obese: 36.3% vs. 19.4%, p = 0.002). One week after surgery, obese patients who received ERAS had higher rates of persistent pain compared with non-obese patients (18.6% vs. 11.1%, p = 0.042). CONCLUSIONS: An opioid-sparing ERAS protocol utilizing multimodal analgesia significantly improved postoperative pain control for obese and non-obese patients. However, it appears that obese patients are still at relatively greater risk for persistent pain after surgery.

Identification of N-benzyltetrahydroisoquinolines as novel anti-neuroinflammatory agents.

A series of simplified berberine analogs was designed, synthesized, and evaluated for anti-inflammatory activity. SAR studies identified N-benzyltetrahydroisoquinoline 7d as a potent berberine analog. 7d suppressed LPS-induced inflammatory cytokine levels in both BV2 cells and primary microglia. Taken together, our results suggest that simplified BB analogs have therapeutic potential as a novel class of anti-neuroinflammatory agents.

Xanthan chain length is modulated by increasing the availability of the polysaccharide copolymerase protein GumC and the outer membrane polysaccharide export protein GumB.

Xanthan is a polysaccharide secreted by Xanthomonas campestris that contains pentameric repeat units. The biosynthesis of xanthan involves an operon composed of 12 genes (gumB to gumM). In this study, we analyzed the proteins encoded by gumB and gumC. Membrane fractionation showed that GumB was mainly associated with the outer membrane, whereas GumC was an inner membrane protein. By in silico analysis and specific globomycin inhibition, GumB was characterized as a lipoprotein. By reporter enzyme assays, GumC was shown to contain two transmembrane segments flanking a large periplasmic domain. We confirmed that gumB and gumC mutant strains uncoupled the synthesis of the lipid-linked repeat unit from the polymerization process. We studied the effects of gumB and gumC gene amplification on the production, composition and viscosity of xanthan. Overexpression of GumB, GumC or GumB and GumC simultaneously did not affect the total amount or the chemical composition of the polymer. GumB overexpression did not affect xanthan viscosity; however, a moderate increase in xanthan viscosity was achieved when GumC protein levels were increased 5-fold. Partial degradation of GumC was observed when only that protein was overexpressed; but co-expression of GumB and GumC diminished GumC degradation and resulted in higher xanthan viscosity than individual GumB or GumC overexpression. Compared with xanthan from the wild-type strain, longer polymer chains from the strain that simultaneously overexpressed GumB and GumC were observed by atomic force microscopy. Our results suggest that GumB-GumC protein levels modulate xanthan chain length, which results in altered polymer viscosity.

A Novel Study Using Accelerated Mass Spectrometry to Evaluate the Pharmacokinetics of Total (14)C AL-8309 (Tandospirone) Following Topical Ocular Administration in Healthy Male Subjects.

The primary objective of this study is to characterize the pharmacokinetics of total (14)C concentrations following bilateral, topical ocular drops of (14)C-AL-8309B labeled either at the pyrimidyl ring (cohort A) position or at the imido-carbonyl ring (cohort B) position twice daily from day 1 through day 6 and once in the morning of day 7 in 16 healthy male subjects (8 per cohort). Each drop (approximately 24 µL) of (14)C-AL-8309B 1.75% ophthalmic solution (equivalent to 420 µg-equiv AL-8309) contained approximately 500 nCi of (14)C-AL-8309. AL-8309 systemic absorption was relatively slow; the time of maximum observed plasma concentrations ranged from 0.25 to 3 hours. Moderate accumulation (1.48- to 1.86-fold) was observed in the mean systemic total (14)C plasma concentrations at steady state (day 7) compared with single dose (day 1). The mean total (14)C eliminated was 3.5-fold and 3.7-fold greater in the urine than the feces for cohort A and cohort B, indicating that (14)C-AL-8309 is primarily excreted through renal elimination. Single and multiple topical doses of AL-8309B were found to be safe and well-tolerated in healthy subjects. This is the first reported use of accelerator mass spectrometry technology with a topically applied ophthalmic product.

Agonists at the serotonin receptor (5-HT(1A)) protect the retina from severe photo-oxidative stress.

PURPOSE: 5-HT(1A) agonists are neuroprotective in CNS injury models. The authors evaluated the efficacy of 5-HT(1A) agonists to protect the retina from severe blue light-induced photo-oxidative damage. METHODS: Albino rats were dosed (subcutaneously) with AL-8309A, 8-OH DPAT, or buspirone once or three times before 6-hour exposure to blue light. Electroretinograms (ERGs) were measured to assess retinal function, and retinal damage was evaluated by light microscopy. Topical ocular dosing with 1.75% AL-8309B was also evaluated. Rats were dosed with WAY-100635, a 5-HT(1A) antagonist, to determine whether protection required activation of the 5-HT(1A) receptor. RESULTS: ERG response amplitudes were significantly (P < 0.05) depressed more than 66% in vehicle-dosed rats after light exposure. ERGs were significantly higher in rats treated with AL-8309A (0.1-30 mg/kg), 8-OH DPAT (0.1-1 mg/kg), buspirone (5-20 mg/kg) or topical ocular with 1.75% AL-8309B. Retinas from AL-8309A and 8-OH DPAT-treated rats were devoid of histologic lesions. Significant protection was measured in rats dosed once 0, 24, or 48 hours before light exposure. Protection provided by dosing with AL-8309B or 8-OH DPAT was inhibited in rats predosed with WAY-100635. CONCLUSIONS: 5-HT(1A) agonists provided potent and complete functional and structural protection. Protection was inhibited by treatment with WAY-100635, confirming the requirement for activating the 5-HT(1A) receptor in initiating this survival pathway. Single-dose experiments with AL-8309A suggest that the mechanism of protection is rapidly activated and protection persists for 48 hours. AL-8309B (1.75%) was effective after topical ocular dosing. AL-8309B is under evaluation in the clinic and may be useful in treating age-related macular degeneration.

Identification and organization of genes for diutan polysaccharide synthesis from Sphingomonas sp. ATCC 53159.

A cluster of genes for diutan polysaccharide synthesis was isolated from a library of Sphingomonas sp. ATCC 53159 genomic DNA by complementation of glucosyl-isoprenylphosphate transferase-deficient mutants of Sphingomonas elodea ATCC 31461 (producing gellan) and Xanthomonas campestris (producing xanthan). The synthesis of polysaccharide in these strains shares a common first step, transfer of glucose-1-phosphate from UDP-glucose to the isoprenylphosphate lipid. The cluster of 24 genes was compared to genes for biosynthesis of gellan, and S-88 sphingan from Sphingomonas sp. ATCC 31554. Diutan, gellan and S-88 sphingan have a common four-sugar backbone but different side chains, one rhamnose for S-88 sphingan, a two-rhamnose side chain for diutan and no side chain for gellan. The genes for biosynthesis of diutan, gellan and S-88 sphingan were similar in general organization but differed in location of some genes, in particular, dpsG (putative polymerase), dpsR (putative lyase) and dpsS (putative repeat unit transporter). An unidentified reading frame urf31, present in the gene clusters for diutan and S-88 sphingan but not gellan, had similarity to glycosyl transferase group 2 proteins, and was detrimental when cloned in Sphingomonas elodea producing gellan that lacks a side chain, but not in Sphingomonas ATCC 31554 producing S-88 sphingan with a rhamnose side chain. Gene urf31 could possibly encode a side-chain rhamnosyl transferase. Another gene urf31.4 was unique to the diutan gene cluster. A plasmid containing 20 of the 24 genes resulted in a slight increase in the amount of diutan produced, but a significant increase in the rheological properties of diutan.

Organization of genes required for gellan polysaccharide biosynthesis in Sphingomonas elodea ATCC 31461.

Sphingomonas elodea ATCC 31461 produces gellan, a capsular polysaccharide that is useful as a gelling agent for food and microbiological media. Complementation of nonmucoid S. elodea mutants with a gene library resulted in identification of genes essential for gellan biosynthesis. A cluster of 18 genes spanning 21 kb was isolated. These 18 genes are homologous to genes for synthesis of sphingan polysaccharide S-88 from Sphingomonas sp. ATCC 31554, with predicted amino acid identities varying from 61% to 98%. Both polysaccharides have the same tetrasaccharide repeat unit, comprised of [-->4)-alpha- l-rhamnose-(1-->3)-beta- d-glucose-(1-->4)-beta- d-glucuronic acid-(1-->4)-beta- d-glucose-(1-->]. Polysaccharide S-88, however, has mannose or rhamnose in the fourth position and has a rhamnosyl side chain, while gellan has no sugar side chain but is modified by glyceryl and acetyl substituents. Genes for synthesis of the precursor dTDP- l-rhamnose were highly conserved. The least conserved genes in this cluster encode putative glycosyl transferases III and IV and a gene of unknown function, gelF. Three genes ( gelI, gelM, and gelN) affected the amount and rheology of gellan produced. Four additional genes present in the S-88 sphingan biosynthetic gene cluster did not have homologs in the gene cluster for gellan biosynthesis. Three of these gene homologs, gelR, gelS, and gelG, were found in an operon unlinked to the main gellan biosynthetic gene cluster. In a third region, a gene possibly involved in positive regulation of gellan biosynthesis was identified.