Effects of doe-litter separation on intestinal bacteria, immune response and morphology of suckling rabbits

[EN] Gut development is stimulated by exposure to microorganisms, especially early-life microbial exposure. This study aimed to investigate whether doe-litter separation, which is performed in many rabbit farms, affects this exposure and therefore inhibits the development of intestinal system in suckling rabbits. Immediately after parturition, Rex rabbit does (n=16) were adjusted to 8 kits per litter and divided into doe-litter separation (DLS) group and doe-litter together (DLT) group based on the conditions of the does. One healthy kit per litter was selected and sacrificed at 7 d, 14 d, 21 d and 28 d of age, and the number of total bacteria, Escherichia coli and Bacteroides-Prevotella, expression of interleukin 6 (IL-6) and interleukin 10 (IL-10) in duodenum and caecum were investigated by real-time polymerase chain reaction. The morphological parameters of duodenum and vermiform appendix were also measured. Our results showed that doe-litter separation affected the number of intestinal bacteria. At 7 d of age, except for caecal Escherichia coli, the number of the investigated bacteria was decreased by doe-litter separation (P<0.05). But 1 wk later, only the number of total bacteria and Bacteroides-Prevotella in caecal content (P<0.05) and Escherichia coli in duodenal content from DLS kits (P<0.05) were still lower than those from DLT kits. After being provided with supplementary food for 7 d, DLS kits had fewer total bacteria in caecal content (P<0.05) and fewer E. coli in duodenal content (P<0.01) than DLT kits. After growing to 28 d of age, kits in DLS group still tended to have fewer total bacteria in caecal content, and expression of IL-10 and secretion of secretory IgA (sIgA) in vermiform appendix in DLS group was obviously lower than kits in DLT group (P<0.05). The villus height:crypt depth ratio in duodenum at 3rd wk and 4th wk was decreased by DLS (P<0.05). Kits in DLS group had shorter villus height (P<0.05), higher crypt depth (P<0.05) and shorter vermiform appendix (P<0.05) at the end of the trial. Furthermore, separating kits from the doe had a negative effect on their average daily gain at 3rd wk and 4th wk (P<0.05). Limiting the microbiological contact with the mother during suckling period affected the kits’ intestinal flora and could negatively affect the development of intestinal digestive and immune system and growth performance of kits.This study was funded by Key Science and Technology Programme of Shaanxi Province (No, 2013K02-18).Zhang, Y.; Cui, H.; Sun, D.; Liu, L.; Xu, X. (2018). Effects of doe-litter separation on intestinal bacteria, immune response and morphology of suckling rabbits. World Rabbit Science. 26(1):71-79. https://doi.org/10.4995/wrs.2018.5917SWORD717926

Carboxymethylcellulose reinforced starch films and rapid detection of spoiled beverages

The integrity of the packaging of a liquid foodstuff makes it difficult to detect spoilage. Therefore, it is important to develop a sensitive, fast and real-time material for liquid food detection. CMC, as lignocellulose derivatives and starch are widely used in the food industry. In this study, starch films with pH-responsive properties are successfully prepared from full-component starch and corn amylopectin (CA) by adding CMC. The effects of CMC on the mechanical properties, morphology characteristics, physical and chemical structures, stability and pH responsiveness of the starch films are analyzed. The starch/CMC-1.0 g composite films display good electrical conductivity and reduce the resistance of the composite film by two orders of magnitude. The composite films have pH response ability; in the simulation of orange juice spoilage experiment, the CA/CMC composite film has a more sensitive current response and was more suitable for the application to liquid food quality detection. Additionally, the starch/CMC composite films have potential applications for rapid detection and real-time monitoring of the safety of liquid food

Controllable Synthesis and Surface Modifications of a Metastable O2-Type Li-Rich Cathode Material

Li-rich materials have become one of the most promising cathode candidates for next-generation lithium-ion battery systems due to their high capacity and operating voltage. Conventional O3-type Li-rich materials undergo a structural transition from a layered to a spinel phase during cycling, leading to the degradation in their electrochemical performance, especially in terms of their voltage decay. The oxygen atoms comprising the structure of O2-type Li-rich materials are stacked in the ABAC configuration, which can effectively suppress these harmful phase transitions. However, O2-type Li-rich materials are metastable structures and can only be synthesized via the means of complex ion exchange methods. In addition, the surface of the material is susceptible to side reactions with the electrolyte when charged to high voltages. Here, we explored the optimal conditions for the synthesis of O2-type Li[Li0.25Ni0.1Co0.05Mn0.6]O2 (LLNCM) in more detail by preparing the precursors using the sol-gel method. Meanwhile, the modification of the material’s surface via low-temperature hydrolysis of aluminum isopropoxide has been proposed for the first time in this study to avoid the damage of metastable materials by the high-temperature coating process. The surface-modified materials prepared under optimal conditions exhibited an excellent electrochemical performance, indicating that a highly stable O2-type bulk phase structure with effective surface modification is a potential way to promote the commercial applications of Li-rich cathode materials

Development of covalent inhibitors: Principle, design, and application in cancer

Abstract Covalent inhibitors have been a rapidly growing field in drug discovery due to their therapeutic potential and unique advantages in cancer therapy. As opposed to noncovalent inhibitory drugs, covalent inhibitors reversibly or irreversibly modify proximal nucleophilic amino acid residues on proteins, aiming to selectively recognize and bind to protein targets and addressing some of the challenges faced by noncovalent drugs. Most successful targeted covalent inhibitors depend primarily on binding‐site cysteine residues, but this has limitations for certain protein targets that lack targetable cysteine residues. Recently, the rational design of covalent inhibitors or covalent probes targeting other nucleophilic residues, such as lysine, tyrosine, serine, has turned out to be another promising strategy for cancer therapy. Thus, the development of novel strategies to extend the scope of covalent binding and improve the binding properties is required. This review gives a summary of the development of covalent inhibitors targeting noncysteine from different aspects, including target identification, structure–activity relationships, drug discovery strategies, and binding properties, in the hope of providing a scientific reference for future covalent drug discovery as a means of expanding research in cancer therapy

Negative Roles of a Novel Nitrogen Metabolite Repression-Related Gene, TAR1, in Laccase Production and Nitrate Utilization by the Basidiomycete Cryptococcus neoformans▿

The multicopper oxidase laccase is widespread in fungi and has great industrial importance. One puzzle regarding laccase production in the basidiomycetous yeast Cryptococcus neoformans is that it is inhibited by high temperature (e.g., 37°C). In this paper, we report identification of a nitrogen metabolite repression-related gene, TAR1, which is responsible for laccase repression. Disruption of TAR1 results in a significant increase in the level of LAC1 mRNA at 37°C. The putative protein Tar1 shares a moderate level of similarity with the nitrogen metabolite repressors Nmr1 and NmrA from Neurospora crassa and Aspergillus nidulans, respectively. Likewise, Tar1 has a negative role in the utilization of nitrate. Furthermore, the structure of Tar1 is unique. Tar1 lacks the long C-terminal region of Nmr1 and NmrA. It contains the canonical Rossmann fold motif, GlyXXGlyXXGly, whereas Nmr1 and NmrA have variable residues at the Gly positions. Interestingly, the promoter region of TAR1 contains three TTC/GAA repeats which are likely the heat shock factor (Hsf) binding sites, implying that Hsf has a role in laccase inhibition. TAR1 mediation of temperature-associated repression of LAC1 suggests a novel mechanism of laccase regulation and a new function for Nmr proteins. Our work may be helpful for industry in terms of promotion of laccase activity

Formation and Band Gap Tuning Mechanism of Multicolor Emissive Carbon Dots from m‐Hydroxybenzaldehyde

Abstract Reported in 2004, carbon dots (CDs) have been widely used in various fields due to their excellent optical properties. However, the mechanism of their fluorescence modulation is still a controversial issue, which also seriously affects the further development of carbon dots. In this paper, m‐hydroxybenzaldehyde is used as a raw material to obtain multicolor luminescent CDs by pyrolysis under different reaction conditions, thereby revealing the forbidden band tuning and formation mechanism of CDs. Different acid–base conditions lead to different reaction paths of the precursors, forming molecular fluorophores with different conjugated structures, which aggregate to eventually form CDs and further enhance the photoluminescence of the system by inhibiting the movement of the fluorescent centers