Topmouth culter (Culter alburnus), a freshwater carnivorous fish of the Cyprinidae, is one of the most popular fish species in aquatic market in China. The anatomy and histology features of fish intestine are very useful for understanding digestive physiology, diagnosing some intestinal diseases and formulating suitable feeds. Thus, here we first characterize topmouth culter intestine via light microscope, transmission electron microscope and scan electron microscope. The 'Z' shaped intestine can be divided into three parts (e.g. the anterior intestine, middle intestine and posterior intestine), with an intestinal coefficient of 0.68. The anterior intestine possessed the longest mucosa folds and thickest muscularis among the three intestinal parts, and microvilli were very well-developed whilst many mitochondria, endoplasmic reticulums and lysosomes were found in which. This indicated the anterior intestine was a main region for digestion and absorption of food in the topmouth culter. While the vacuoles observed in the posterior intestine may be closely related to the intracellular digestion. Neutral and acid mucus were strongly present throughout the intestine. This detailed descriptive paper will be very helpful for studies of topmouth culter related to its digestive physiology, intestinal disease control and feed nutrient.

D-Alanyl esters on lipoteichoic acid (LTA) are involved in adhesion, biofilm formation, resistance to cationic antimicrobial peptides, and immune stimulation. There is evidence that bacteria can modulate the level of D-alanyl esters on LTA in response to challenge, but the mechanism of regulation appears to be different among bacteria. In this study, expression of the dlt operon responsible for D-alanylation of LTA was examined in the commensal bacterium Streptococcus gordonii. dlt expression was assessed using the dlt promoter-lacZ reporter gene assay, LTA D-alanine content measurements and dlt mRNA quantification. The results showed that dlt expression was growth phase-dependent, with the greatest expression at the mid-exponential phase of growth. In contrast to Staphylococcus aureus, dlt expression in Strep. gordonii was not affected by the exogenous addition of Mg 2+ or K + . Interestingly, dlt expression was upregulated under acidic conditions or when cells were stressed with polymyxin B, indicating that cell envelope stress may be a signal for dlt expression. In view of these results, mutants defective in the cell envelope stress LiaSR two-component regulatory system were constructed. The liaS and liaR mutants showed an increase in dlt expression over the parent strain at neutral pH. The mutants failed to respond to low pH and polymyxin B stress; dlt expression remained the same in the presence or absence of these stresses. These results suggest that dlt expression in Strep. gordonii is regulated by the LiaSR regulatory system in response to environmental signals such as pH and polymyxin B. The regulation appears to be complex, involving both repression and activation mechanisms. INTRODUCTIONLipoteichoic acid (LTA) is an amphiphilic polymer of polyphosphoglycerol or polyphosphoribitol anchored to the cytoplasmic membrane by a glycolipid. Each phosphoglycerol or phosphoribitol on this molecule may be modified by glycosylation or, more often, substituted with D-alanyl esters (Fischer, 1988;Fischer et al., 1990). The dlt operon is responsible for the D-alanylation of LTA (Neuhaus & Baddiley, 2003). The operon consists of four genes, dltA, dltB, dltC and dltD. The dltA gene encodes the D-alanyl carrier protein ligase (Dcl), which activates the D-alanine and ligates it to the D-alanyl carrier protein (Dcp). The function of the protein encoded by dltB has not been experimentally established, but it is a transport protein that is thought to serve as a channel to secrete the unfolded D-alanyl Dcp. The dltD gene encodes a membraneassociated protein, which facilitates the binding of Dcp and Dcl for ligation of Dcp with D-alanine. Disruption of any one of the dlt genes will eliminate D-alanylation of LTA.D-Alanylation confers a positive charge upon LTA and has been demonstrated to have a role in the regulation of autolytic activity (Fischer et al., 1981), the binding of Mg 2+ (Archibald et al., 1973), intragenic coaggregation (Clemans et al., 1999), biofilm formation (Fabretti et al., 2006;Gross et al., 2001), adhere...

Since the invention of lithium‐ion batteries as a rechargeable energy storage system, it has uncommonly promoted the development of society. It has a wide variety of applications in electronic equipment, electric automobiles, hybrid vehicles, and aerospace. As an indispensable component of lithium‐ion batteries, anode materials play an essential role in the electrochemical characteristics of lithium‐ion batteries. In this review, we described the development from lithium‐metal batteries to lithium‐ion batteries in detail on the time axis as the first step; This was followed by an introduction to several commonly used anode materials, including graphite, silicon, and transition metal oxide with discussions the charge‐discharge mechanism, challenges and corresponding strategies, and a collation of recent interesting work; Finally, three anode materials are summarized and prospected. Hopefully, this review can serve both the newcomers and the predecessors in the field.

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A versatile strategy involving one-step desilication of coke-deposited spent zeolite catalyst was successfully developed to prepare hierarchical porous carbon monoliths (HPCMs).