The study concluded that the resulting specimens lack toes in taller ants.

a-amylase is a glucosidase that hydrolyzes a1,-4 glyosidic bonds between monosaccharides. Maltose and Sucrose are also linked by a1,4 linkages but during digestion, they are hydrolyzed by brush border disaccharidases. Why is this so? Why can't a-amylase do the job?

Thank you.

Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAPs) and cancer risk in the prospective NutriNet-Santé cohort

Charlotte Debras, Eloi Chazelas, Bernard Srour, Chantal Julia, Élodie Schneider, Emmanuelle Kesse-Guyot, Cédric Agaësse, Nathalie Druesne-Pecollo, Valentina A Andreeva, Gaëlle Wendeu-Foyet ... Show more The Journal of Nutrition, nxab379, https://doi.org/10.1093/jn/nxab379 Published: 29 October 2021

Abstract Background Fermentable Oligosaccharides, Disaccharides and Monosaccharides And Polyols (FODMAPs) have been shown to be involved in gastrointestinal disorders. In view of their pro-inflammatory potential and their interactions with the gut microbiota, their contribution to the etiology of other chronic diseases such as cancer has been postulated. However, no epidemiological study has investigated this hypothesis so far.

Objective Our objective was to investigate the associations between FODMAP intake (total and by type) and cancer risk (overall, breast, prostate and colorectal) in a large prospective cohort.

Design The study was based on the NutriNet-Santé cohort (2009–2020); 104,909 adult participants without cancer at baseline were included in our analyses (median follow-up time = 7.7y, 78.7% women, mean age at baseline 42.1y (SD = 14.5)). Baseline dietary intakes were obtained from repeated 24h-dietary records linked to a detailed food composition table. Associations between FODMAP intake (expressed in quintiles, Q) and cancer risks were assessed by Cox proportional hazard models adjusted for a large range of lifestyle, sociodemographic and anthropometric variables.

Results Total FODMAP intake was associated with increased overall cancer risk (n = 3374 incident cases, HR for sex-specific Quintile 5 versus Quintile 1: 1.21; 95%CI: 1.02, 1.44; P-trend = 0.04). In particular, oligosaccharides were associated with cancer risk: a trend was observed for overall cancer (HR Q5 vs. Q1: 1.10; 95%CI: 0.97, 1.25; P-trend = 0.04) and colorectal cancer (n = 272, HR Q5 vs. Q1: 1.78; 95%CI: 1.13–2.79; P-trend = 0.02).

Conclusion Results from this large population-based study on French adults from the NutriNet-Santé cohort show a significant association between FODMAP intake and the risk of cancer development. Further epidemiological and experimental studies are needed to confirm these results and provide data on the potential underlying mechanisms

https://academic.oup.com/jn/advance-article-abstract/doi/10.1093/jn/nx

GlcNAc2 is the core disaccharide fragment present in N‐glycans exposed on the surface of enveloped viruses of high health concern, such as coronaviruses. Because N‐glycans are directly involved in the docking of viruses to host cells, recognition of GlcNAc2 by a biomimetic receptor may be a convenient alternative to the use of lectins to interfere with viral entry and infection. Herein we describe a simple biomimetic receptor recognizing the methyl‐β‐glycoside of GlcNAc2 in water with an unprecedented affinity of 160 µM, exceeding that of more structurally complex receptors reported in the literature. The tweezers‐shaped acyclic structure exhibits marked selectivity among structurally related disaccharides, and complete discrimination between mono‐ and disaccharides. Molecular modelling calculations supported by NOE data provided a three‐dimensional description of the binding mode, shedding light on the origin of the affinities and selectivities exhibited by the receptor.

https://ift.tt/3c4EFRb

Wording's a little off but you get what I'm asking

So I'm reviewing my notes from the whole past school year and am a little confused because I wrote that disaccharides are made from 2-7 Monosaccharides and I'm a bit sceptical and am unsure if that's true

Do we need to know the structures of all of these? Or the types of bonds formed in between monomers in the disaccharide and oligosaccharide structures? Just not really sure what I should be knowing, short of memorizing every single thing about them..

Is this a reducing sugar?

Reasons I think it's reducing:

1. The carbon on the far right is attached to an OH and a O-R group which is the requirement of a hemiacetal.

2. Fructose is a reducing sugar

Reason I think it's not reducing:

1. The CH2OH on the far right would not allow the ring structure to open? (not actually sure about that statement)

Thanks for the help!

The highly stereoselective synthesis of 1,1′‐disaccharides was achieved using 1,2‐dihydroxyglycosyl acceptors and glycosyl donors in the presence of a tricyclic borinic acid catalyst. In this reaction, the complexation of the diols and the catalyst is crucial for the activation of glycosyl donors, as well as for the 1,2‐ cis ‐configuration of the products. The anomeric stereochemistry of the glycosyl donor depends on the employed glycosyl donor. Applications of the produced 1,1′‐disaccharides are also described.

https://ift.tt/2WgQZH9

1.

glucose + fructose = Sucrose

(Good F__king Sh_t)

(Goonies F__king Sucks)

2.

galactose + glucose = Lactose

(Gather a Good Laugh)

3.

Glucose + Glucose = Maltose (alpha linkage of glu-glu)

(Good Guys Matter)

(Gig Gle More)

or (Glue Glues Matters)

P.s. I like goonies :) The phrase just sticks though.

I know we have to memorize the structures of glucose, fructose, mannose and galactose as the main monosaccharides and I have those down but I don’t have the disaccharides down and the connectivity. Can someone enlighten me plz? Thanks!

Hey! I need to learn how to name Disaccharides/Polysaccharides, but I'm not understanding my textbook's instructions. I see how you determine if a monosaccharide is alpha or beta, but I'm confused about how to number the linkages/change the name once another monosaccharide is added to the chain. Do you guys have any tips for naming?

I was recently diagnosed with a mild disaccharide intolerance to sucrose, lactose and maltose.

I still need to see a dietician but until then I need advice on foods, recipes that I can eat without GI troubles. So far I have followed pretty much a low carb diet of non-starchy vegetables, meat and some fruit.

Also if anyone is aware of good books on the subject that may be helpful those would be appreciated.

I'm not asking for treatment advice, just advice on what to eat.

This response says that the Anomeric Carbon's Oxygen is released.

However, this internet diagram shows that the Anomeric Carbon's Oxygen is kept.

So which one is it really?

Think simple. In the development of biomimetic receptors for carbohydrates, an approach that focuses on simple acyclic architectures can be successfully exploited for disaccharide recognition, provided that the correct binding geometry can be achieved. Here we present a simple tweezers‐shaped receptor that selectively recognizes in water GlcNAc2, the core fragment of N‐glycans exposed on the surface of enveloped viruses, such as coronaviruses.

Abstract

GlcNAc2 is the core disaccharide fragment present in N‐glycans exposed on the surface of enveloped viruses of high health concern, such as coronaviruses. Because N‐glycans are directly involved in the docking of viruses to host cells, recognition of GlcNAc2 by a biomimetic receptor may be a convenient alternative to the use of lectins to interfere with viral entry and infection. Herein, we describe a simple biomimetic receptor recognizing the methyl‐β‐glycoside of GlcNAc2 in water with an unprecedented affinity of 160 μM, exceeding that of more structurally complex receptors reported in the literature. The tweezers‐shaped acyclic structure exhibits marked selectivity among structurally related disaccharides, and complete discrimination between mono‐ and disaccharides. Molecular modelling calculations supported by NOE data provided a three‐dimensional description of the binding mode, shedding light on the origin of the affinities and selectivities exhibited by the receptor.

https://ift.tt/3ukX1om

The highly stereoselective synthesis of 1,1′‐disaccharides was achieved by using glycosyl 1,2‐diols and glycosyl donors in the presence of a tricyclic borinic acid catalyst. The complexation between the diol and the catalyst is crucial for the activation of the glycosyl donors and the cis configuration of the product, whereas the anomeric stereochemistry of the glycosyl donor depends on the employed glycosyl donor.

Abstract

The highly stereoselective synthesis of 1,1′‐disaccharides was achieved by using 1,2‐dihydroxyglycosyl acceptors and glycosyl donors in the presence of a tricyclic borinic acid catalyst. In this reaction, the complexation of the diols and the catalyst is crucial for the activation of glycosyl donors, as well as for the 1,2‐cis ‐configuration of the products. The anomeric stereochemistry of the glycosyl donor depends on the employed glycosyl donor. Applications of the produced 1,1′‐disaccharides are also described.

https://ift.tt/2WgQZH9