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Role of Lectins in Gastrointestinal Disorders
Published in Megh R. Goyal, Preeti Birwal, Durgesh Nandini Chauhan, Herbs, Spices, and Medicinal Plants for Human Gastrointestinal Disorders, 2023
Patients with long-standing inflammatory bowel disease (IBD) are thought to be at increased risk for later development of colon cancer. Abnormal goblet cell glycoconjugates, reflected in alterations in lectin staining patterns, were reported in patients with ulcerative colitis.9 Similar findings were reported in New World monkeys with spontaneously developing colitis, although the precise significance was uncertain.8 Though other investigators have found peanut lectin-binding sites in the colon of patients with ulcerative colitis,16 yet changes appeared to be similar to controls and reversible with the development of quiescence of colonic mucosal inflammation. In a subsequent study of colonic biopsies from patients with ulcerative colitis or Crohn’s disease, changes, particularly in peanut agglutinin positivity, could not be confirmed.46
Host Defenses Against Prototypical Intracellular Protozoans, the Leishmania
Published in Peter D. Walzer, Robert M. Genta, Parasitic Infections in the Compromised Host, 2020
Richard D. Pearson, Mary E. Wilson
Sacks et al. (46,47) found that logarithmic L. major promastigotes were agglutinated by peanut agglutinin but that the 50% of stationary-phase organisms, which were infective, were not. They then used peanut agglutinin to effectively purify infective, stationary-stage, metacyclic L. major promastigotes. A monoclonal antibody raised against peanut agglutinin-negative infective promastigotes was found to recognize a surface antigen not present on logarithmic, noninfective promastigotes. Unfortunately, peanut agglutinin does not differentiate between noninfective and infective promastigotes of all other Leishmania species.
Manufacturing food extracts
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
Natalie A. David, Anusha Penumarti, Jay E. Slater
The major allergens in peanut are vicilin seed storage protein (Ara h 1) and conglutin (Ara h 2). The minor peanut allergens include glycinin (Ara h 3, previously Ara h 4), profilin (Ara h 5), other conglutin family members (Ara h 6, 7), and peanut agglutinin (Ara h agglutinin). Changes in peanut allergenicity with thermal processing can be divided into two categories: dry heating (roasting) and wet heating (boiling and frying). Temperatures achieved using roasting can be higher than in frying or boiling [70]. Roasting peanuts decreases the solubility of the major peanut allergens, while IgE-binding remains unchanged [71] or increases [72]. Maleki et al. show that roasted peanuts have increased allergenicity, approximately 90-fold higher than raw peanuts, and that the protein modifications caused by the Maillard reaction contribute to this effect [72]. The Maillard reaction is a form of nonenzymatic browning in which amino acids react with reducing sugars. In addition, boiling or frying peanuts significantly decreases the IgE-binding of Ara h 1, Ara h 2, and Ara h 3 when compared to raw or roasted peanuts [73]. This finding is recapitulated in a mouse model of allergy using Ara h 2 purified from heat-treated peanuts [74]. Finally, a study of peanut-allergic patients shows that the SPT wheal sizes and IgE-binding properties of peanut protein extracts are significantly lower when extracts were made from boiled compared to raw peanuts and when extracts from raw, fried, and roasted peanuts are subjected to specific conditions of heat and pressure compared to their untreated forms [75].
Taurine Protects Retinal Cells and Improves Synaptic Connections in Early Diabetic Rats
Published in Current Eye Research, 2020
Yichao Fan, Jie Lai, Yuanzhi Yuan, Liyang Wang, Qingping Wang, Fei Yuan
The loss of vision in adult animals is mainly attributed to a loss of cone photoreceptors; we therefore examined cone photoreceptors in diabetic rats, detailing cone damage and subsequent cone loss (Figure 4). Cone photoreceptors were labelled with the peanut agglutinin lectin (PNA) (Figure 4a, green). In both cases, the number of cone photoreceptors appeared to be lower in diabetic animals (group II) than in controls (group I), whereas the numbers of cone photoreceptors appeared to be preserved by taurine supplementation (Figure 4a, group III and group IV). The quantification of PNA immunopositive outer/inner segments confirmed that diabetes generated a 21.8% cone inner/outer segment loss (n = 10, p < .01) (Figure 4a,b), and the morphological changes of the cone inner/outer segment (shortening, enlargement and distortion compared with group I) were also observed in the diabetic group (Figure 4a, group II). The numbers of cones after taurine administration were only 2% and 11% lower than those observed in controls (group I), indicating that taurine supplementation prevented 50% of the diabetes-induced cone cell loss (Figure 4b) and that the morphological changes were nearly maintained (Figure 4a, group III and IV). Moreover, similar results were found in terms of RGC quantification. The number of RGCs appeared to be lower in diabetic animals (group II) than in controls, whereas the numbers of RGCs appeared to be preserved by taurine supplementation (Figure 4a, red, group III and IV). The quantification of Brn3a immunopositive cells confirmed that diabetes generated a 38.3% RGC loss (n = 10, p < .01) (Figure 4c). The numbers of RGCs after taurine administration were only 6% and 5.8% lower than the numbers observed in controls (group I), indicating that taurine supplementation prevented 84% of the diabetes-induced RGC loss (Figure 4c).
Cargo and cell-specific differences in extracellular vesicle populations identified by multiplexed immunofluorescent analysis
Published in Journal of Extracellular Vesicles, 2020
Kevin Burbidge, Virginia Zwikelmaier, Ben Cook, Michael M. Long, Barak Balva, Michael Lonigro, Grace Ispas, David J. Rademacher, Edward M. Campbell
We also examined the glycan composition associated with S15Ch+ EVs by staining with a panel of biotinylated lectins which bind to carbohydrates of differing sugar linkages present on glycoproteins and glycolipids present in EVs. Furthermore, we also assessed whether inhibition of lysosomal acidification altered the glycan composition by treating cells with bafilomycin-A1. Bafilomycin-A1 has previously been shown to alter the secretion of both EVs and cargoes that undergo autophagic driven secretion [13,34]. Representative images of Lycopersicon esculentum (Tomato) Lectin (LEL) reveal S15Ch and LEL co-localization under vehicle and bafilomycin-A1 conditions (Figure 7(a)). Among the lectins tested, we found that when lysosomes were not inhibited, ~85% of the S15Ch+ EVs were bound by Lens culinaris agglutinin (LCA), (LEL), Pisum sativum agglutinin (PSA) and Ricinus communis agglutinin-1 (RCA1); Erythrina cristagalli lectin (ECL), Phaseolus vulgaris leuco-agglutinin (PHA-L), soybean agglutinin (SBA), and Solanum tuberosum(Potato) lectin (STL) bound ~50–85% of S15ch+ EVs; Griffonia simplicifolia lectin 1&2 (GSL1), (GSL2), peanut agglutinin (PNA), Ulex europaeus agglutinin 1 (UEA1), and Viciavillosa agglutinin (VVA) bound ~25–50% of EVs; and Sophora japonica agglutinin (SJA) as well as Succinylated Wheat Germ agglutinin (sWGA) bounds less than 25% of EVs (Figure 7(b)). Interestingly, we found that bafilomycin-A1 treatment altered the lectin binding of S15Ch+ EVs, with significant reductions measured in ECL, LEL, PHA-L and PSA staining, while the binding of other lectins was unaffected (Figure 7(b)). Collectively our data show that lectin binding to EVs can be assessed microscopically in the context of the EV-MAC workflow and reveals that lysosomal inhibition alters the glycan composition of EVs released under basal conditions, based on the observed changes in lectin binding profile.
Intranasal administration of erythropoietin rescues the photoreceptors in degenerative retina: a noninvasive method to deliver drugs to the eye
Published in Drug Delivery, 2019
Ye Tao, Chong Li, Anhui Yao, Yingxin Qu, Limin Qin, Zuojun Xiong, Jianbin Zhang, Weiwen Wang
The enucleated eyecups were immersed in a fixative solution containing 4% paraformaldehyde (Dulbecco's PBS; Mediatech, Inc., Herndon, VA) overnight at 4 °C. The anterior segments were cut off and the retinas were rinsed with PB (phosphate buffer), dehydrated in a graded ethanol series, and embedded in paraffin wax. Retinal sections (thickness of 5 μm) were cut vertically and then were stained with hematoxylin and eosin (HE). The thicknesses of the ONL were measured at 250 µm intervals along the vertically superior-inferior axis by a single observer in a masked fashion. Data from three sections (selected randomly from six sections) were averaged for each eye. The ONL thicknesses of ten eyes were averaged for each animal group. On the other hand, retinal whole-mount preparations were generated by first removing the optic nerve head and then carefully separating the neuroretina from the eyecup. Subsequently, the retinal specimens were rinsed in 0.01 M PBS, permeabilized in 0.3% Triton X-100, and blocked in 3% BSA for 1 hour at room temperature. The peanut agglutinin (PNA) conjugated to an Alexa Fluor 488 (1: 200, L21409, Invitrogen, USA), S-cone opsin, or M-cone opsin antibodies (1: 400, Millipore, MA, USA) were diluted in 0.1% Triton X-100 and 1% BSA in PBS, and then were incubated with retinal specimen overnight at 4 °C. After 3 rinses with PBS, the retinal specimens were incubated in Cy3-conjugated anti-rabbit IgG (1:400, Jackson ImmunoResearch Laboratories, USA) and DAPI. Retinal specimens were rapidly rinsed with 0.01 M PBS five times and then were coverslipped with anti-fade Vectashield mounting medium (Vector Labs, Burlingame, CA, USA) for photographing. Fluorescence was analyzed with the Zeiss LSM 510 META microscope (Zeiss, Thornwood, NY, USA) fitted with Axiovision Rel. version 4.6 software (Carl Zeiss AG Manufacturing company, Oberkochen, Germany). All fluorescent images were captured using identical exposure settings. The cone numbers of four 420 × 420 μm squares which located 1 mm dorsal, temporal, ventral, and nasal to the center of the optic nerve were determined.