One-Pot Assembly of Mannose-Capped Lipoarabinomannan Motifs up to 101-Mer from the Mycobacterium tuberculosis Cell Wall

Lipoarabinomannan (LAM) from the Mycobacterium tuberculosis cell envelope represents important targets for the development of new therapeutic agents against tuberculosis, which is a deadly disease that has plagued mankind for a long time. However, the accessibility of long, branched, and complex lipoarabinomannan over 100-mer remains a long-standing challenge. Herein, we report the modular synthesis of mannose-capped lipoarabinomannan 101-mer from the M. tuberculosis cell wall using a one-pot assembly strategy on the basis of glycosyl ortho-(1-phenylvinyl)benzoates (PVB), which not only accelerates the modular synthesis but also precludes the potential problems associated with one-pot glycosylation with thioglycosides. Shorter sequences including 18-mer, 19-mer, and 27-mer are also synthesized for in-depth structure-activity relationship biological studies. Current synthetic routes also highlight the following features: (1) streamlined synthesis of various linear and branched glycans using one-pot orthogonal glycosylation on the combination of glycosyl N-phenyltrifluoroacetimidates, glycosyl ortho-alkynylbenzoates, and glycosyl PVB; (2) highly stereoselective construction of 10 1,2-cis-arabinofuranosyl linkages using 5-O-(2-quinolinecarbonyl)-directing 1,2-cis-arabinofuranosylation via a hydrogen-bond-mediated aglycone delivery strategy; and (3) convergent [(18 + 19) × 2 + 27] one-pot synthesis of the 101-mer LAM polysaccharide. The present work demonstrates that this orthogonal one-pot glycosylation strategy can highly streamline the chemical synthesis of long, branched, and complex polysaccharides.

High power 1.55 µm buried heterojunction distributed feedback laser with a linewidth less than 200 kHz

With the rapid development of coherent optical communication systems, lasers are required to have higher power and narrower linewidths. In this paper, a process method using buried heterojunction is proposed. By comparing the optoelectronic properties of lasers with different mesa widths and different cavity lengths, the laser with a 1000 µm cavity length and a mesa width of 2.4 µm can reach 133.7 mW at 25°C at 300 mA, and a side mode suppression ratio (SMSR) greater than 50 dB. This laser also exhibits low relative intensity noise (<-150d B/H z at 260 mA) and narrow linewidth (<200k H z).

Immunogenicity and protective efficacy of a fusion protein vaccine consisting of antigen Ag85B and HspX against Mycobacterium tuberculosis infection in mice

Subunit vaccines have the potential advantage to boost Mycobacterium bovis Bacillus Calmette-Guérin (BCG)-primed immunity in adults. However, most candidates are antigens highly expressed in replicating bacilli but not in dormant or persisting bacilli, which exist during Mycobacterium tuberculosis infection. We constructed M. tuberculosis fusion protein Ag85B-Mpt64(190-198) -HspX (AMH) and Ag85B-Mpt64(190-198) -Mtb8.4 (AMM), which consist of Ag85B, the 190-198 peptide of Mpt64, HspX (Rv2031c) and Mtb8.4 (Rv1174c), respectively. AMH and/or AMM were mixed with adjuvants composed of dimethyl-dioctyldecyl ammonium bromide and BCG polysaccharide nucleic acid (DDA-BCG PSN) to construct subunit vaccines. Mice were immunized thrice with Ag85B, AMH and AMM vaccines and the immunogenicity of the fusion protein vaccines was determined. Then, mice were primed with BCG and boosted twice with Ag85B, AMH, AMM and AMM + AMH vaccines, respectively, followed by challenging with M. tuberculosis virulent strain H37Rv, and the immune responses and protective effects were measured. It was found that mice immunized with AMH vaccine generated high levels of antigen-specific cell-mediated responses. Compared with the group injected only with BCG, the mice boosted with AMM, AMH and AMM + AMH produced higher levels of Ag85B-specific IgG1 and IgG2a and IFN-γ-secreting T cells upon Ag85B and Mycobacterium tuberculosis purified protein derivative (PPD) stimulation. It is interesting that only mice boosted with AMM + AMH had significantly lower bacterial count in the lungs than those receiving BCG, whereas mice boosted with AMH or AMM did not. The results suggest that AMH consisting of HspX, the antigen highly expressed in dormant bacilli, could be combined with antigens from replicating bacilli to enhance BCG primed immunity so as to provide better protection against both growing and non-growing bacteria that occur during the infection process.

[The bred technique of Zaocys dhumnades]

This paper reports the observational data on the laying egg, hatching, life habit, relationship between capacity for eating and growth speed of Zaocys dhumnades bred in enclosure-like garden of snake, summarizes an available breeding technique.

[Observation on TXB2 and 6-keto-PGF1 alpha in serum of patients with cor pulmonale]

To know the changes of TXA2 and PGI2 in serum of patients with cor pulmonale, the levels of their stable metabolites TXB2 and 6-keto-PGF1 alpha in serum were examined in 28 patients with cor pulmonale during alleviation, 29 patients with cor pulmonale during exacerbation before and after treatment and 10 healthy subjects. TXB2 and 6-keto-PGF1 alpha were 109.74 +/- 56.14 ng/L and 54.76 +/- 35.62 ng/L respectively in healthy subjects; TXB2/6-keto-PGF1 alpha = 2.004. The TXB2 level of patients with cor pulmonale at every stage was higher than that of healthy subjects (P < 0.05-0.01). Patients with cor pulmonale during exacerbation had the highest TXB2 level of 709.22 +/- 354.49 ng/L, which decreased to 408.24 +/- 289.41 ng/L (P < 0.05) after treatment with traditional Chinese medicine combined with western medicine and the decreased level as such was not significantly different from that during alleviation (333.14 +/- 324.14 ng/L). The 6-keto-PGF1 alpha level in patients with cor pulmonale at every stage was not significantly different from that of healthy subjects. Since TXB2 increased, the value TXB2/6-keto-PGF1 alpha of patients with cor pulmonale was greater than that of healthy subjects. It is most likely that chronic hypoxia and hypercapnia lead to prostaglandin release in the lung of patients with cor pulmonale; hypoxia and hypercapnia become more severe during exacerbation resulting from infection; which lead to increased prostaglandin release, then high TXB2 level ensue as the result. TXB2 decreases after amelioration of hypoxia during treatment. But the change of 6-keto-PGF1 alpha is not obvious.