Uncovering a Latent Ligation Site for Glycopeptide Synthesis

2008 ◽  
Vol 47 (29) ◽  
pp. 5402-5406 ◽  
Author(s):  
Ryo Okamoto ◽  
Yasuhiro Kajihara
Keyword(s):  
Ligation Site

Enhancement of sortase A-mediated protein ligation by inducing a β-hairpin structure around the ligation site

2011 ◽  
Vol 47 (16) ◽  
pp. 4742 ◽  
Author(s):  
Yuichi Yamamura ◽  
Hidehiko Hirakawa ◽  
Satoshi Yamaguchi ◽  
Teruyuki Nagamune
Keyword(s):  
Hairpin Structure ◽  
Sortase A ◽  
Protein Ligation ◽  
Ligation Site

scholarly journals Natural 2′,5′-Phosphodiester Bonds Found at the Ligation Sites of Peach Latent Mosaic Viroid

2001 ◽  
Vol 75 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Fabien Côté ◽  
Dominique Lévesque ◽  
Jean-Pierre Perreault
Keyword(s):  
Circular Rna ◽  
Rolling Circle ◽  
Phosphodiester Bonds ◽  
Biological Importance ◽  
Rolling Circle Mechanism ◽  
Ligation Site

ABSTRACT Peach latent mosaic viroid (PLMVd) is a circular RNA pathogen that replicates in a DNA-independent fashion via a rolling circle mechanism. PLMVd has been shown to self-ligate in vitro primarily via the formation of 2′,5′-phosphodiester bonds; however, in vivo the occurrence and necessity of this nonenzymatic mechanism are not evident. Here, we unequivocally report the presence of 2′,5′-phosphodiester bonds at the ligation site of circular PLMVd strands isolated from infected peach leaves. These bonds serve to close the linear conformers (i.e., intermediates), yielding circular ones. Furthermore, these bonds are shown to stabilize the replicational circular templates, resulting in a significant advantage in terms of viroid viability. Although the mechanism responsible for the formation of these 2′,5′-phosphodiester bonds remains to be elucidated, a hypothesis describing in vivo nonenzymatic self-ligation is proposed. Most significantly, our results clearly show that 2′,5′-phosphodiester bonds are still present in nature and that they are of biological importance.

scholarly journals Ligation site in proteins recognized in silico

2006 ◽  
Vol 1 (4) ◽  
pp. 127-129 ◽  
Author(s):  
Michal Brylinski ◽  
Leszek Konieczny ◽  
Irena Roterman
Keyword(s):  
In Silico ◽  
Ligation Site

Exercise training effects on collateral and microvascular resistances in rat model of arterial insufficiency

1995 ◽  
Vol 268 (1) ◽  
pp. H125-H137 ◽  
Author(s):  
J. M. Lash ◽  
J. C. Nixon ◽  
J. L. Unthank
Keyword(s):  
Exercise Training ◽  
Rat Model ◽  
Arterial Occlusion ◽  
Primary Site ◽  
Training Effects ◽  
Arterial Ligation ◽  
Acute Arterial Occlusion ◽  
Arterial Insufficiency ◽  
Collateral Vessels ◽  
Ligation Site

Experiments were performed to determine if exercise training reduces collateral or microvascular resistances in the hindlimb of rats with arterial insufficiency. After right femoral arterial ligation (age 10 wk), rats were divided into sedentary (Sed) and treadmill-trained (Tr) groups (7–9 wk, final intensity: 27 m/min, 6 degree grade, 60 min/day). Minimal resistances (mmHg.ml-1.min.100 g) of the total limb (RT), collateral vessels (RC), and the microcirculations distal (Rfmc) and proximal (Rimc) to the ligation site were determined during pump perfusion of the hindlimbs. RT was lower in nonligated (open) and acutely ligated limbs of Tr than Sed rats (open: 0.69 +/- 0.011 vs. 0.93 +/- 0.071; acute: 0.92 +/- 0.028 vs. 1.18 +/- 0.070 mmHg.ml-1.min.100 g) but not in chronically ligated limbs (chronic: 0.88 +/- 0.072 vs. 1.00 +/- 0.046 mmHg.ml-1.min.100 g). RC was similar between the chronically ligated limbs of Sed and Tr rats (1.69 +/- 0.165 vs. 1.97 +/- 0.227 mmHg.ml-1.min.100 g) and was approximately 70% lower than in acutely ligated limbs of both groups. Rfmc and Rimc were not affected by arterial ligation, but Rimc was significantly lower in Tr than in Sed rats (acute: 1.05 +/- 0.026 vs. 1.54 +/- 0.163; chronic: 1.24 +/- 0.071 vs. 1.81 +/- 0.202 mmHg.ml-1.min.100 g). These results indicate that the primary site of vascular adaptations to chronic arterial ligation is in the collateral vessels. Exercise training does not significantly alter the collateralization process but may provide protection against acute arterial occlusion by stimulating microvascular growth.

scholarly journals NGF-stimulated retrograde transport of trkA in the mammalian nervous system.

1995 ◽  
Vol 130 (1) ◽  
pp. 149-156 ◽  
Author(s):  
M D Ehlers ◽  
D R Kaplan ◽  
D L Price ◽  
V E Koliatsos
Keyword(s):  
Nervous System ◽  
Sciatic Nerve ◽  
Western Blot ◽  
Blot Analysis ◽  
Retrograde Transport ◽  
Model System ◽  
Specific Antibodies ◽  
Ngf Receptor ◽  
Ligation Site

The present study was designed to clarify the in vivo function of trkA as an NGF receptor in mammalian neurons. Using the rat sciatic nerve as a model system, we examined whether trkA is retrogradely transported and whether transport is influenced by physiological manipulations. Following nerve ligation, trkA protein accumulates distal to the ligation site as shown by Western blot analysis. The distally accumulating trkA species were tyrosine phosphorylated. The trkA retrograde transport and phosphorylation were enhanced by injecting an excess of NGF in the footpad and were abolished by blocking endogenous NGF with specific antibodies. These results provide evidence that, upon NGF binding, trkA is internalized and retrogradely transported in a phosphorylated state, possibly together with the neurotrophin. Furthermore, our results suggest that trkA is a primary retrograde NGF signal in mammalian neurons in vivo.

Duplex Ultrasound Assessment of Neovascularization after Saphenofemoral or Sapheno-Popliteal Junction Ligation

1997 ◽  
Vol 12 (2) ◽  
pp. 64-68 ◽  
Author(s):  
M. G. De Maeseneer ◽  
K. P. Ongena ◽  
F. Van den Brande ◽  
P. E. Van Schil ◽  
S. G. De Hert ◽  
...  
Keyword(s):  
Clinical Assessment ◽  
Varicose Veins ◽  
Duplex Ultrasound ◽  
University Hospital ◽  
Single Patient ◽  
Previous Surgery ◽  
Varicose Vein Surgery ◽  
Ultrasound Assessment ◽  
Ligation Site ◽  
Communicating Vein

Objective: Evaluation of neovascularization at the saphenous ligation site as a cause of recurrent varicose veins. Design: Prospective duplex study of a single patient group. Setting: Vascular clinic of a University Hospital. Patients: 131 patients (177 limbs) were evaluated 2 and 12 months after varicose vein surgery. Intervention: Clinical assessment and colour duplex scanning of operated limbs. Main outcome measures: Limbs were classified according to the degree of neovascularization: grade 0 = no new communicating vein, grade 1 = new communicating vein with diameter <4 mm, and grade 2 = new communicating vein with diameter >4 mm and pathological reflux. Results: Two months postoperatively, grade 0 was observed in 173 limbs (98%) and grade 1 in four limbs (2%). Twelve months postoperatively, 152 limbs (86%) scored grade 0, 16 limbs (9%) grade 1 and nine limbs (5%) grade 2. Conclusions: After correctly performed previous surgery, neovascularization of varying degree may occur within 1 year, as can be demonstrated on postoperative duplex examination.

scholarly journals Use of Polyamide (Nylon) Cable Ties for Vascular Ligation of Healthy Equine Jejunal Mesentery

2021 ◽  
Vol 8 ◽  
Author(s):  
Samuel D. Hurcombe ◽  
Holly A. Roessner ◽  
Chelsea E. Klein ◽  
Julie B. Engiles ◽  
Klaus Hopster
Keyword(s):  
Operative Time ◽  
Healthy Adult ◽  
Long Term Effects ◽  
Short Term ◽  
Polyglactin 910 ◽  
Mesenteric Vessel ◽  
Vascular Ligation ◽  
Vascular Arcade ◽  
Ligation Site

Jejunal vascular ligation is an essential step in performing jejunojejunostomy. Hand sewn ligation is typically used and can increase operative time with long sections of bowel to be removed. Nylon cable ties (NCT) have been used for vascular ligation in horses but are yet to be investigated for application on the mesenteric vasculature of the gastrointestinal tract. Our objective was to evaluate the efficacy and short-term safety of NCT jejunal mesenteric vessel ligation in healthy horses. Eight healthy adult horses underwent midline celiotomy. A segment of jejunal mesentery was identified (≥4 arcades). Briefly, three fenestrations (proximal, middle, distal) were made 5–10 mm apart adjacent to the first and last vascular arcade to be ligated. Two sterilized NCT were passed to encircle the mesentery through the proximal and middle fenestrations, separated by intact mesentery. NCT were closed tightly and the vascular pedicle transected with Mayo scissors through the distal fenestration. Jejunojejunostomy was then performed and the mesentery sutured closed. The number of vascular arcades and time to ligate using NCT were recorded. At 2 weeks, horses underwent repeat celiotomy to assess the healing of the NCT ligation site and an equal number of vascular arcades were hand sewn double ligated using 2-0 Polyglactin 910 as a timed comparison. NCT mesenteric ligation was significantly faster than hand sewn methods (P &lt; 0.01). Effective hemostasis was achieved in all cases. There was no evidence of local infection or adhesions at 14 days post-operatively. Further investigation in the long-term effects in horses as well as horses with strangulating jejunal lesions are needed for clinical application.

Assessment of the Impact of Enforced Expression of Platelet Derived Growth Factor Beta in Human Mesenchymal Stem Cells and Contribution to Blood Flow Restoration.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3568-3568
Author(s):  
Claus Sondergaard ◽  
Fernando Antonio Fierro ◽  
Jeannine McGee ◽  
Jan A. Nolta
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Blood Flow ◽  
Mesenchymal Stem Cells ◽  
Hind Limb ◽  
Limb Ischemia ◽  
Platelet Derived Growth Factor ◽  
Growth Factor Beta ◽  
Ligation Site

Abstract Abstract 3568 Poster Board III-505 Both mesenchymal stem cells (MSC) and platelet derived growth factor beta (PDGFB) have been shown to promote angiogenesis in vivo and are therefore interesting therapeutic agents for the restoration of blood flow to ischemic tissues encountered in peripheral artery disease and critical limb ischemia. Careful evaluation of the mechanisms responsible for neovessel formation in stem cell-based therapeutic angiogenesis is critical for developing efficient treatment strategies. Previous studies have shown that MSCs correspond to pericytes, which are lost in PDGFB-null mice, suggesting that MSCs strongly rely on PDGFB signaling in vivo. Our major aim was to establish a highly sensitive method to assess whether overexpression of PDGFB in MSCs could modulate expression of pro-angiogenic cytokines and improve the restoration of bloodflow in an established murine xenograft model of hind limb ischemia. Human bone marrow derived MSCs (passage 2-5) were transduced with either a lentiviral vector containing the coding sequence of PDGFB or the same vector without PDGFB (control). As expected, overexpression of PDGFB strongly enhanced the proliferation of MSCs, reducing the doubling time from 51 to 20 hours (n=4, p<0.05). This effect correlated with a shift of 15% of cells from the G0/G1 to the S/G2/M phase, as compared to controls, when measured by flow cytometry of propidium iodide stained cells. Next, we induced a unilateral hind limb ischemia in NODSCIDbeta2null mice by excision of the femoral artery and performed intravenous transplantation of 2.5×10e5 MSCs (control MSC vs. PDGFB-MSC) the day following surgery. Recovery of blood flow to the affected limb was assessed at days 0 ((before transplantation), n=11), 4 (n=11), 7 (n=9), 10 (n=6), and 14 (n=6) by laser doppler imaging and values were normalized to the non-ischemic contralateral leg. Treated animals of both groups (control and PDGFB overexpressing MSC) exhibited a steadily progressive recovery in blood flow in the region proximal to the primary ligation site, reaching near normal levels by day 10. Surprisingly, no significant difference was seen in the blood flow recovery in animals receiving the PDGF over expressing MSCs. Donor MSCs (control and PDGFB) homed to the site of injury, as assessed by immunofluorescent staining of the ischemic muscle in the regions proximal and distal to the primary ligation site at days 4 and 7. However, the rapid recovery in blood flow did not appear to be attributed to a direct differentiation or integration of MSC into the vasculature, but rather through the expression of paracrine angiogenic factors. Interestingly, overexpression of PDGF reduced FGF2 mRNA expression levels in MSC (n=4, p=0.056), suggesting that high levels of PDGFB may indeed lead to a reduction of other key angiogenic factors, explaining the mild effect of PDGFB in vivo. Our results show that, although overexpression of PDGFB in bone marrow-derived MSCs enhanced the proliferation of MSC in vitro, it did not impact the speed or magnitude of blood flow recovery to the ischemic hind limb as compared to native MSCs, likely due to down modulation of other key angiogenic signals including FGF2. Disclosures: No relevant conflicts of interest to declare.

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