Nosiheptide is a typical thiopeptide antibiotic displaying potent activity toward various drug-resistant strains of Gram-positive pathogens.Although nosiheptide lacks in vivo activity, and good water-solubility with a series of uncontrollable analogues, which may limit its clinical application, glycosylated analogues may overcome problem of low activity and may improve its druggability.In search of novel glycosylated nosiheptide producers, we applied a genome mining strategy that identified Actinoalloteichus sp.AHMU CJ021 that contains all genes required.However, despite the presence of a predicted glycosyltransferase, glycosylated derivatives of nosiheptide were not detected, after following one strain many compounds (OSMAC) strategy and heterologous expression of a regulatory protein NocP.Nevertheless, nosiheptide produced by this strain was remarkably pure, and further experiments were conducted to improve its production by optimization of the culture medium.Under optimal conditions, 58.73 mg/L nosiheptide was produced, representing an almost 6-fold improvement compared to the original fermentation medium.Therefore, we consider Actinoalloteichus sp.AHMU CJ021 a suitable potential candidate for industrial production of nosiheptide, which provides the basis for solving the problem of nosiheptide structural analogues.

BACKGROUND:There is no consensus on the optimal bone tunnel position in the lateral clavicle,which guides coracoclavicular ligament reconstruction.Postoperative complications such as enlargement of the lateral clavicle bone tunnel,bone osteolysis,clavicle fracture,and failure of internal fixation are likely to occur.Bone mass density plays an important role in the strength and stability of endophytic fixation.Regional differences in the bone mass density of the distal clavicle should not be overlooked in the repair and reconstruction of acromioclavicular dislocation.Currently,there are no quantitative clinical studies in humans regarding the bone mass density of the distal clavicle. OBJECTIVE:To measure the magnitude of bone mass density in different regions of the distal clavicle by quantitative CT to provide a reference for surgeons to repair and reconstruct the coracoclavicular ligament. METHODS:101 patients undergoing quantitative CT checking in Fuyang People's Hospital Affiliated to Anhui Medical University from October to December 2022 were enrolled,from which 1 616 samples of subdivisional bone mass density of the distal clavicle were measured.For each of the quantitative CT samples,firstly,the distal clavicle was divided medially to laterally into the following four regions:conical nodal region(region A),inter-nodal region(region B),oblique crest region(region C)and distal clavicular region(region D).Secondly,each region was divided into the first half and the second half to determine eight subdivisions,then setting semiautomatic region of interest(ROI)in each subdivision:(ROI A1,A2,B1,B2,C1,C2,D1,and D2).Thirdly,each quantitative CT scan was transferred to the quantitative CT pro analysis workstation,and cancellous bone mass density was measured in the distal clavicle ROI.Finally,the clavicular cortex was avoided when measuring. RESULTS AND CONCLUSION:(1)There was no statistically significant difference in bone mineral density on the different sides of the shoulder(P＞0.05).(2)The analysis of bone mineral density in eight sub-areas of the distal clavicle A1,A2,B1,B2,C1,C2,D1,and D2 showed statistically significant differences(P＜0.05).It could be considered that there were differences in bone mineral density in different areas of the distal clavicle.After pairwise comparison,there was no statistically significant difference in bone mineral density between A1 and A2,D1 and D2,A2 and B1(P＞0.05),and there was a statistically significant difference in bone mineral density between the other sub-areas(P＜0.05).(3)The bone mineral density in the region A2 of the anatomical insertion of the conical ligament was significantly higher than that in the inter-nodular area(region B)(P＜0.05).The bone mineral density in the region A1 was higher than that in the region A2,but the difference was not statistically significant(P＞0.05).The bone mineral density in the region C1 of the anatomical insertion of the trapezium ligament was higher than that in regions C2,D1 and D2,and the bone mineral density in the inter-nodular area(region B)was significantly higher than that in regions C and D(P＜0.05).(4)These results have suggested that there are differences in bone mass density in different regions of the distal clavicle;regional differences in bone mass density in the distal clavicle during repair and reconstruction of acromioclavicular dislocation cannot be ignored.Consideration should be given not only to biomechanical factors but also to the placement of implants or bone tunnels in regions of higher bone mass density,which could improve the strength and stability of implant fixation and reduce the risk of complications such as bone tunnel enlargement,osteolysis,fracture and implant failure.

Objective:To investigate the efficacy of arthroscopic superior capsular reconstruction using composite autologous patch graft combined with tenodesis of the long head of the biceps tendon in the treatment of irreparable massive rotator cuff tears (IMRCT).Methods:A retrospective case series study was performed on 11 IMRCT patients who were admitted to Affiliated Fuyang Hospital of Bengbu Medical University (Fuyang People′s Hospital) from May 2020 to June 2022, including 7 males and 4 females, aged 54-74 years [(62.6±7.3)years]. All the patients were treated with arthroscopic superior capsular reconstruction using composite patch graft combined with tenodesis of the long head of the biceps tendon. The Visual Analogue Scale (VAS), Acromiohumeral Distance (AHD), Constant-Murley score and University of California Los Angeles (UCLA) score and active range of motion of the shoulder joint before, at 6 months after surgery and at the last follow-up were compared. At the last follow-up, the integrity of reconstructed superior capsule and the long head of the biceps tendon was evaluated using MRI of the shoulder joint. Postoperative complications were observed.Results:All the patients were followed up for 13-39 months [16(13, 36)months]. The VAS score, AHD, Constant-Murley score, and UCLA score were 2(2, 3)points, (9.1±1.1)mm, (56.1±5.4)points, and (19.7±2.8)points respectively at 6 months after surgery, which were all significantly improved from those before surgery [6(5, 7)points, (5.1±1.2)mm, (37.9±2.2)points, and (11.8±1.2)points] ( P<0.05). The VAS score, AHD, Constant-Murley score, and UCLA score were 0(0, 1)points, (8.4±0.9)mm, (83.6±3.8)points, and (28.2±2.3)points respectively at the last follow-up, which were all significantly improved from those before surgery ( P<0.05). At the last follow-up, the VAS score or AHD were not significantly improved from those at 6 months after surgery ( P>0.05); Constant-Murley score and UCLA score were both significantly improved from those at 6 months after surgery ( P<0.05). At 6 months after surgery, shoulder active ranges of motion in forward flexion, abduction and external rotation were (134.6±13.5)°, (124.6±18.6)° and 45(40, 50)° respectively, which were all significantly improved compared with those before surgery [(63.2±36.1)°, (65.0±23.1)°, and [30(20, 40)°] ( P<0.05). At the last follow-up, shoulder active ranges of motion in forward flexion, abduction and external rotation were (144.1±12.6)°, (139.6±15.4)° and 60(45, 65)° respectively, which were all significantly improved compared with those before surgery ( P<0.05). There were no significant differences in active range of motion of the shoulder in forward flexion, abduction and external rotation between 6 months after surgery and the last follow-up ( P>0.05). At the last follow-up, MRI revealed integrity of the reconstructed superior joint capsule and the long head of the biceps tendon in 10 patients. One patient developed resorption of the greater tuberosity and 1 showed a partial tear of the supraspinatus tendon at 1 year after surgery. Conclusion:Arthroscopic superior capsular reconstruction using composite autologous patch graft combined with tenodesis of the long head of the biceps tendon can relieve shoulder pain, decrease upward displacement of the humerus head, improve the function and range of motion of the shoulder joint, and reduce complications in the treatment of IMRCT.