Shewanella algae and Microbulbifer elongatus from marine macro-algae - isolation and characterization of agar-hydrolysing bacteria

Genome sequences of four agarolytic bacteria from the Bacteroidia and Gammaproteobacteria

Here we present the genomes of four marine agarolytic bacteria belonging to the Bacteroidota and Proteobacteria. Two genomes are closed and two are in draft form, but all are at least 99% complete and offer new opportunities to study agar-degradation in marine bacteria.

The effects of macro-algae supplementation on serum lipid, glycaemic control and anthropometric indices: A systematic review and meta-analysis of clinical trials

INTRODUCTION

Macro-algae products have been shown to ameliorate the metabolic disorders state. Thus, highlighting their function as supplementary therapeutic agents can be a novel strategy for clinical therapies. This systematic review and meta-analysis of clinical trials aimed to summarize the effect of macro-algae consumption on serum lipid profile, glycaemic control and anthropometric factors.

METHODS

In this systematic review and meta-analysis, a comprehensive search was performed for relevant studies published up to May 2023. The Cochran's Q test and I-square (I2 ) tests were used to evaluate heterogeneity across the included studies. The meta-analysis was conducted using random-effects model (DerSimonian and Laird), and weighted mean difference (WMD) was considered as the pooled effect size.

RESULTS

Out of 8602 papers in the initial screening, eight clinical trials with a total of 438 participants were included into this meta-analysis. The results indicated that macro-algae supplementation significantly decreased serum levels of total cholesterol (TC) (WMD = -6.7 mg/dL; 95% CI: -12.59, -0.80; item = 0.026) and low-density lipoprotein cholesterol (LDL-c) (WMD = -8.25 mg/dL; 95% CI: -15.38, -1.12; p-value = .023). There was an increase in level of high-density lipoprotein cholesterol (HDL-c) (WMD = 0.48 mg/dL; 95% CI: -2.05, 3.01; p-value = .71) which was not statistically significant. Macro-algae supplementation reduced body mass index (BMI) (WMD = -0.28 kg/m2 ; 95% CI: -0.96, 0.41; p-value = .426), weight (WMD = -0.39 kg; 95% CI: -3.6, 2.83; p-value = .81), waist circumference (WC) (WMD = -0.52 cm; 95% CI: -2.71, 1.66; p-value = .64), fasting blood sugar (FBS) (WMD = -1.95 mg/dL; 95% CI: -5.19, 1.28; p-value = .24) and HbA1c (WMD = -0.02%; 95% CI: -0.14, 0.09; p-value = .66) in intervention group.

CONCLUSIONS

This meta-analysis indicated that macro-algae supplementation significantly decreased TC and LDL-c level. It can also increase HDL-c level and reduce anthropometric indices and glycaemic control factors.

The degradation activities for three seaweed polysaccharides of Shewanella sp. WPAGA9 isolated from deep-sea sediments

Seaweed oligosaccharides possess great bioactivities. However, different microbial strains are required to degrade multiple polysaccharides due to their limited biodegradability, thereby increasing the cost and complexity of production. Shewanella sp. WPAGA9 was isolated from deep-sea sediments in this study. According to the genomic and biochemical analyses, the extracellular fermentation broth of WPAGA9 had versatile degradation abilities for three typical seaweed polysaccharides including agar, carrageenan, and alginate. The maximum enzyme activities of the extracellular fermentation broth of WPAGA9 were 71.63, 76.4, and 735.13 U/ml for the degradation of agar, alginate, and carrageenan, respectively. Moreover, multiple seaweed oligosaccharides can be produced by the extracellular fermentation broth of WPAGA9 under similar optimum conditions. Therefore, WPAGA9 can simultaneously degrade three types of seaweed polysaccharides under similar conditions, thereby greatly reducing the production cost of seaweed oligosaccharides. This finding indicates that Shewanella sp. WPAGA9 is an ideal biochemical tool for producing multiple active seaweed oligosaccharides at low costs and is also an important participant in the carbon cycle process of the deep-sea environment.