Vitamin C (VC) is an essential nutrient for many animals. However, whether insects, including Bombyx mori, can synthesize VC remains unclear. In this article, the optimized HPLC method was used to determine the content of l‐ascorbic acid (AsA) in silkworm eggs, larvae and pupae, and the activity of l‐gulono‐1,4‐lactone oxidase (GULO), a key enzyme in VC synthesis. The RNA interference method was used to determine the effect of the BmGulo‐like gene on embryonic development and GULO activity in the pupal fat body. The AsA content increased significantly during E144 h–E168 h in the late embryonic stage and P48 h–P144 h in the middle‐late pupal stage, in which exogenous VC was not ingested. Furthermore, the body AsA content in larvae fed VC‐free feed also increased with larval stage. The GULO enzymatic activity was present in eggs and the fat bodies of larvae and pupae, even when the larvae were reared with fresh mulberry leaves. Moreover, the activity was higher in the later embryonic stages (E144 h–E168 h) and the early pupal stage (before P24 h). The GULO activity in the pupal fat body dramatically decreased when the screened BmGulo‐like gene (BGIBMGA005735) was knocked down with small interfering RNA; in addition, the survival rate and hatching rate of eggs significantly decreased 21% and 44%, respectively, and embryonic development was delayed. Thus, Bombyx mori can synthesize AsA through the l‐gulose pathway, albeit with low activity, and this synthesis ability varies with developmental stages.

No abstract

Bombyx mori silk is a super-long natural protein fiber with a unique structure and excellent performance. Innovative silk structures with high performance are in great demand, thus resulting in an industrial bottleneck. Herein, the outer layer sericin SER3 is ectopically expressed in the posterior silk gland (PSG) in silkworms via a piggyBac-mediated transgenic approach, then secreted into the inner fibroin layer, thus generating a fiber with sericin microsomes dispersed in fibroin fibrils. The water-soluble SER3 protein secreted by PSG causes P25’s detachment from the fibroin unit of the Fib-H/Fib-L/P25 polymer, and accumulation between the fibroin layer and the sericin layer. Consequently, the water solubility and stability of the fibroin-colloid in the silk glandular cavity, and the crystallinity increase, and the mechanical properties of cocoon fibers, moisture absorption and moisture liberation of the silk also improve. Meanwhile, the mutant overcomes the problems of low survival and abnormal silk gland development, thus enabling higher production efficiency of cocoon silk. In summary, we describe a silk gland transgenic target protein selection strategy to alter the silk fiber structure and to innovate its properties. This work provides an efficient and green method to produce silk fibers with new functions.

Metabolic disorders of the circulatory system of animals (e.g., hyperglycemia and hyperlipidemia) can significantly affect immune function; however, since there is currently no reliable animal model for hyperproteinemia, its effects on immunity remain unclear. In this study, we established an animal model for hyperproteinemia in an invertebrate silkworm model, with a controllable plasma protein concentration (PPC) and no primary disease effects. We evaluated the influence of hyperproteinemia on innate immunity. The results showed that high PPC enhanced hemolymph phagocytosis via inducing a rapid increase in granulocytes. Moreover, while oenocytoids increased, the plasmacytes quickly dwindled. High PPC inhibited hemolymph melanization due to decreased phenoloxidase (PO) activity in the hemolymph via inhibiting the expression of the prophenoloxidase-encoding genes, PPO1 and PPO2. High PPC upregulated the gene expression of antimicrobial peptides via differential activation of the Toll and Imd signaling pathways associated with NF-κB signaling, followed by an induction of inconsistent antibacterial activity towards Gram-positive and Gram-negative bacteria in an animal model of high PPC. Therefore, high PPC has multiple significant effects on the innate immune function of the silkworm circulatory system.

No abstract

Hyperproteinemia is a severe metabolic disease characterized by abnormally elevated plasma protein concentrations (PPC). However, there is currently no reliable animal model for PPC, and the pathological mechanism of hyperproteinemia thus remains unclear. In this study, we evaluated the effects of hyperproteinemia on reproductive development in an invertebrate silkworm model with a controllable PPC and no primary disease effects. High PPC inhibited the synthesis of vitellogenin and 30K protein essential for female ovarian development in the fat body of metabolic tissues, and inhibited their transport through the hemolymph to the ovary. High PPC also induced programmed cell death in testis and ovary cells, slowed the development of germ cells, and significantly reduced the reproductive coefficient. Furthermore, the intensities and mechanisms of high-PPC-induced reproductive toxicity differed between sexes in this silkworm model.

ObjectivesTo describe 6-min walk test (6MWT) outcomes, and to investigate their correlations with cardiopulmonary and lung function among patients with interstitial lung disease (ILD) which was not limited to idiopathic pulmonary fibrosis.MethodsWe collected patients’ demographic data and obtained minute-by-minute 6MWT outcomes. Modified Borg scale was employed to assess patients’ dyspnoea, whereas New York Heart Association (NYHA) classification and pulmonary function test were used to evaluate patients’ cardiopulmonary functions.ResultsHeart rate (HR) exhibited a continuous upward trend, while SpO2 exhibited an overall downward with a slight increase at the fifth minute. The SpO2 nadir for 70 patients (9.3%) was lower than 80%. Further, the SpO2 nadir for 78.27% of the participants appeared at the end of the fourth minute. The 6-min walk distance (6MWD) had the strongest correlation with NYHA classification (r=0.82, p<0.01). The ratio of 6MWD to predicted 6MWD was most correlated to forced expiratory volume in the first second (r=0.30, p<0.01) and forced vital capacity (r=0.30, p<0.01). SpO2 at 3 min had the strongest correlation to patients’ diffusing capacity of the lungs for carbon monoxide (r=0.41, p<0.01). We found significant differences in 6MWD (F=2.44, p=0.033), SpO2 change (F=2.58, p=0.025), HR at 0 min (F=2.87, p=0.014), HR at end of 6 min (F=2.58, p=0.025) and HR zenith (F=2.64, p=0.022) between the subtypes of ILD.ConclusionThis observation provided an important evidence regarding oxygen titration. It is better to maintain SpO2 above 88% for 4 min instead of 3 min. SpO2 at the third minute was the most valuable predictor of patients’ lung function. 6MWD and SpO2 changes were more discriminative in subtypes.

Bombyx mori silk is a super-long natural protein fiber with a unique structure and excellent performance. Innovative silk structures with high performance are in great demand, thus resulting in an industrial bottleneck. Herein, a transgenic method was used in which the outer layer sericin SER3 in silk is secreted into the inner fibroin layer, thus generating a new structural fiber with non-fibrous sericin microsomes dispersed in fibroin fibrils. The water-soluble SER3 protein secreted by the posterior silk gland causes P25’s detachment from the fibroin unit of the Fib-H/Fib-L/P25 polymer and accumulation on the fibroin surface. Moreover, the water solubility and stability of the fibroin-colloid in the silk glandular cavity are increased, thus significantly improving the β-sheet content of fibroin, as well as the mechanical properties, moisture absorption and moisture liberation of the silk fiber. Our silkworm mutant system circumvents the problems of low vitality and abnormal silk gland development, and enables higher production efficiency of cocoon silk than that of the wild type. We describe a silk gland transgenic target protein selection strategy to alter the ancient silk fiber structure and to innovate the properties of silk protein materials. This study thus provides an efficient, green method to produce new silk fibers.