Serum alpha-tocopherol, all-trans retinol, total lipids and cholesterol in the black rhinoceros (Diceros bicornis)

1. Mean concentration of serum alpha-tocopherol (Vitamin E) in 28 free-living black rhinoceroses sedated during translocation in Zimbabwe was 1.92 (SD, 0.43) mg/l. 2. Alpha-tocopherol was not detectable (less than 0.15 mg/l) in five captive black rhinoceroses held at London Zoo. 3. Circulating levels of all-trans retinol (Vitamin A) were not different between the two groups. 4. The low level of alpha-tocopherol in captive rhinoceroses suggests a risk of acute haemolytic anaemia.     

Rapid reprogramming of haemoglobin structure‐function exposes multiple dual‐antimicrobial potencies

The intrinsic cytotoxicity of cell‐free haemoglobin (Hb) has hampered the development of reliable Hb‐based blood substitutes for over seven decades. Notably, recent evidence shows that the Hb deploys this cytotoxic attack against invading microbes, albeit, through an unknown mechanism. Here, we unraveled a rapid molecular reprogramming of the Hb structure‐function triggered by virulent haemolytic pathogens that feed on the haem‐iron. On direct contact with the microbe, the Hb unveils its latent antimicrobial potency, where multiple antimicrobial fragments are released, each harbouring coordinated ‘dual‐action centres’: microbe binding and pseudoperoxidase (POX) cycle activity. The activated Hb fragments anchor onto the microbe while the juxtaposed POX instantly unleashes a localized oxidative shock, killing the pathogen‐in‐proximity. This concurrent action conceivably restricts the diffusion of free radicals. Furthermore, the host astutely protects itself from self‐cytotoxicity by simultaneously releasing endogenous antioxidants. We found that this decryption mechanism of antimicrobial potency is conserved in the ancient invertebrate respiratory protein, indicating its fundamental significance. Our definition of dual‐antimicrobial centres in the Hb provides vital clues for designing a safer Hb‐based oxygen carrier blood substitute.     

MALE ORIENTATION INHIBITOR OF COTTON BOLLWORM: IDENTIFICATION OF COMPOUNDS PRODUCED BY MALE HAIRPENCIL GLANDS1)

Abstract  Extracts of hairpencils ffom male cotton bollworm moth were analyzed by capillary gas chromatography, acid methanolysis, and GC-MS. Ten components have been identified as_: 14; OH, 14: Ac, 14: COOH, 211–16: OH, 16: OH, 16: Ac, 16: COOH, 18: OH, 18: Ac, and 18: COOH. Based on the statistics of titer of each chemical, the total amount of three saturated alcohols is over 75%. The amounts of the chemicals in the hairpencils are related to the age of males. There are no chemicals identified in the extracts from males less than 10 h after eclosion, then the quantity of compounds increased rapidly during 48 h after adult eclosion. After 5 days, the quantity decreased.     

Rewiring central carbon metabolism for tyrosol and salidroside production in Saccharomyces cerevisiae

Metabolic engineering of Saccharomyces cerevisiae for high-level production of aromatic chemicals has received increasing attention in recent years. Tyrosol production from glucose by S. cerevisiae is considered an environmentally sustainable and safe approach. However, the production of tyrosol and salidroside by engineered S. cerevisiae has been reported to be lower than 2 g/L to date. In this study, S. cerevisiae was engineered with a push-pull-restrain strategy to efficiently produce tyrosol and salidroside from glucose. The biosynthetic pathways of ethanol, phenylalanine, and tryptophan were restrained by disrupting PDC1, PHA2, and TRP3. Subsequently, tyrosol biosynthesis was enhanced with a metabolic pull strategy of introducing PcAAS and EcTyrA^M53I/A354V. Moreover, a metabolic push strategy was implemented with the heterologous expression of phosphoketolase (Xfpk), and then erythrose 4-phosphate was synthesized simultaneously by two pathways, the Xfpk-based pathway and the pentose phosphate pathway, in S. cerevisiae. Furthermore, the heterologous expression of Xfpk alone in S. cerevisiae efficiently improved tyrosol production compared with the coexpression of Xfpk and phosphotransacetylase. Finally, the tyrosol yield increased by approximately 135-folds, compared with that of parent strain. The total amount of tyrosol and salidroside with glucose fed-batch fermentation was over 10 g/L and reached levels suitable for large-scale production.     

The Effects of Hsp90α1 Mutations on Myosin Thick Filament Organization

Heat shock protein 90α plays a key role in myosin folding and thick filament assembly in muscle cells. To assess the structure and function of Hsp90α and its potential regulation by post-translational modification, we developed a combined knockdown and rescue assay in zebrafish embryos to systematically analyze the effects of various mutations on Hsp90α function in myosin thick filament organization. DNA constructs expressing the Hsp90α1 mutants with altered putative ATP binding, phosphorylation, acetylation or methylation sites were co-injected with Hsp90α1 specific morpholino into zebrafish embryos. Myosin thick filament organization was analyzed in skeletal muscles of the injected embryos by immunostaining. The results showed that mutating the conserved D90 residue in the Hsp90α1 ATP binding domain abolished its function in thick filament organization. In addition, phosphorylation mimicking mutations of T33D, T33E and T87E compromised Hsp90α1 function in myosin thick filament organization. Similarly, K287Q acetylation mimicking mutation repressed Hsp90α1 function in myosin thick filament organization. In contrast, K206R and K608R hypomethylation mimicking mutations had not effect on Hsp90α1 function in thick filament organization. Given that T33 and T87 are highly conserved residues involved post-translational modification (PTM) in yeast, mouse and human Hsp90 proteins, data from this study could indicate that Hsp90α1 function in myosin thick filament organization is potentially regulated by PTMs involving phosphorylation and acetylation.     

GABAB Receptor Constituents Revealed by Tandem Affinity Purification from Transgenic Mice

GABA_B receptors function as heterodimeric G-protein-coupled receptors for the neurotransmitter γ-aminobutyric acid (GABA). Receptor subtypes, based on isoforms of the ligand-binding subunit GABA_B1, are thought to involve a differential set of associated proteins. Here, we describe two mouse lines that allow a straightforward biochemical isolation of GABA_B receptors. The transgenic mice express GABA_B1 isoforms that contain sequences for a two-step affinity purification, in addition to their endogenous subunit repertoire. Comparative analyses of purified samples from the transgenic mice and wild-type control animals revealed two novel components of the GABA_B1 complex. One of the identified proteins, potassium channel tetramerization domain-containing protein 12, associates with heterodimeric GABA_B receptors via the GABA_B2 subunit. In transfected hippocampal neurons, potassium channel tetramerization domain-containing protein 12 augmented axonal surface targeting of GABA_B2. The mice equipped with tags on GABA_B1 facilitate validation and identification of native binding partners of GABA_B receptors, providing insight into the molecular mechanisms of synaptic modulation.