Cell culture–based production of defective interfering influenza A virus particles in perfusion mode using an alternating tangential flow filtration system

Respiratory diseases including influenza A virus (IAV) infections represent a major threat to human health. While the development of a vaccine requires a lot of time, a fast countermeasure could be the use of defective interfering particles (DIPs) for antiviral therapy. IAV DIPs are usually characterized by a large internal deletion in one viral RNA segment. Consequentially, DIPs can only propagate in presence of infectious standard viruses (STVs), compensating the missing gene function. Here, they interfere with and suppress the STV replication and might act “universally” against many IAV subtypes. We recently reported a production system for purely clonal DIPs utilizing genetically modified cells. In the present study, we established an automated perfusion process for production of a DIP, called DI244, using an alternating tangential flow filtration (ATF) system for cell retention. Viable cell concentrations and DIP titers more than 10 times higher than for a previously reported batch cultivation were observed. Furthermore, we investigated a novel tubular cell retention device for its potential for continuous virus harvesting into the permeate. Very comparable performances to typically used hollow fiber membranes were found during the cell growth phase. During the virus replication phase, the tubular membrane, in contrast to the hollow fiber membrane, allowed 100% of the produced virus particles to pass through. To our knowledge, this is the first time a continuous virus harvest was shown for a membrane-based perfusion process. Overall, the process established offers interesting possibilities for advanced process integration strategies for next-generation virus particle and virus vector manufacturing. Key points • An automated perfusion process for production of IAV DIPs was established. • DIP titers of 7.40E + 9 plaque forming units per mL were reached. • A novel tubular cell retention device enabled continuous virus harvesting. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00253-021-11561-y

Myanmar Climate-Smart Agriculture Strategy

Myanmar has committed to apply CSA to contribute to regional food security and environmental protection during the 24th ASEAN Summit on May 10, 2014. The Myanmar CSA strategy encompasses the development of technical, policy and investment conditions to achieve a sustainable agricultural development for food security and nutrition through climate-resilient and sustainable agriculture. Myanmar’s CSA strategy aims to be socially, culturally and politically appropriate, environment-friendly and economically feasible to promote and attain sustainable agriculture, food security and nutrition, agricultural development and climate change adaptation and mitigation. Myanmar’s CSA strategy also aims to provide context and analysis for addressing agriculture in international climate negotiations to better inform climate negotiators and other stakeholders by identifying options and unpacking issues of interest

Mode-resolved reciprocal space mapping of electron-phonon interaction in the Weyl semimetal candidate Td-WTe2_2

The selective excitation of coherent phonons provides unique capabilities to control fundamental properties of quantum materials on ultrafast time scales. For instance, in the presence of strong electron-phonon coupling, the electronic band structure can become substantially modulated. Recently, it was predicted that by this means even topologically protected states of matter can be manipulated and, ultimately, be destroyed: For the layered transition metal dichalcogenide Td-WTe$_2$, pairs of Weyl points are expected to annihilate as an interlayer shear mode drives the crystalline structure towards a centrosymmetric phase. By monitoring the changes in the electronic structure of Td-WTe$_2$ with femtosecond resolution, we provide here direct experimental evidence that the coherent excitation of the shear mode acts on the electronic states near the Weyl points. Band structure data in comparison with our results imply, furthermore, the periodic reduction in the spin splitting of bands near the Fermi energy, a distinct electronic signature of the non-centrosymmetric Td ground state of WTe$_2$. The comparison with higher-frequency coherent phonon modes finally proves the shear mode-selectivity of the observed changes in the electronic structure. Our real-time observations reveal direct experimental insights into electronic processes that are of vital importance for a coherent phonon-induced topological phase transition in Td-WTe$_2$.Comment: 28 pages, 17 figure

Evolution of the most recent common ancestor of a population with no selection

We consider the evolution of a population of fixed size with no selection. The number of generations $G$ to reach the first common ancestor evolves in time. This evolution can be described by a simple Markov process which allows one to calculate several characteristics of the time dependence of $G$. We also study how $G$ is correlated to the genetic diversity.Comment: 21 pages, 10 figures, uses RevTex4 and feynmf.sty Corrections : introduction and conclusion rewritten, references adde

Nociceptin/Orphanin FQ receptor expression in clinical pain disorders and functional effects in cultured neurons

The Nociceptin/Orphanin FQ peptide receptor (NOP), activated by its endogenous peptide ligand Nociceptin/Orphanin FQ (N/OFQ), exerts several effects including modulation of pain signalling. We have examined, for the first time, the tissue distribution of the NOP receptor in clinical visceral and somatic pain disorders by immunohistochemistry, and assessed functional effects of NOP and [micro] opioid receptor activation in cultured human and rat dorsal root ganglion (DRG) neurons. Quantification of NOP-positive nerve fibres within the bladder sub-urothelium revealed a remarkable several-fold increase in Detrusor Overactivity (p<0.0001) and Painful Bladder Syndrome patient specimens (p=0.0014), compared to controls. In post-mortem control human DRGs, 75-80% of small/medium neurons (<=50 [micro]m diameter) in the lumbar (somatic) and sacral (visceral) DRG were positive for NOP, and fewer large neurons; avulsion-injured cervical human DRG neurons showed similar numbers. NOP-immunoreactivity was significantly decreased in injured peripheral nerves (p=0.0004), and also in painful neuromas (p=0.025). Calcium imaging studies in cultured rat DRG neurons demonstrated dose-dependent inhibition of capsaicin responses in the presence of N/OFQ, with an IC50 of 8.6 pM. In cultured human DRG neurons, 32% inhibition of capsaicin responses was observed in the presence of 1 pM N/OFQ (p<0.001). The maximum inhibition of capsaicin responses was greater with N/OFQ than [mu]-opioid receptor agonist DAMGO. Our findings highlight the potential of NOP agonists, particularly in urinary bladder overactivity and pain syndromes. The regulation of NOP expression in visceral and somatic sensory neurons by target-derived neurotrophic factors deserves further study, and the efficacy of NOP selective agonists in clinical trials

MOLECULAR STRUCTURE OF GELATIN EXTRACTED FROM PARROT (Scarus sp) FISH SCALES

One of the protein molecules of fish scales is water soluble gelatin. Gelatin of fish scales could be best substitute of commercial available gelatin which derived from porcine and bovine. The purpose of this study was to determine the molecular structure of gelatin extracted from marine fish scale using Fourier transform infrared (FTIR) analysis, and to obtain the moisture content, pH and yield of gelatin. Samples were prepared from the wet and dried scales. As for the standard gelatin, the gelatin of the two samples are characterized with several types of amide groups. The two gelatin samples were slight different in absorption of wave length for amide A, B, I, II and III groups indicating the instability of the functional groups which may influence viscosity and gel strength. For the wet scales derived gelatin, the wave number absorption was found to be 3412 cm-1 (amide A), 2421 cm-1 (amide B), 1653 cm-1 (amide I), 1400 cm-1 (amide II), and 1001 cm-1 (amide III), while for the dried scales derived gelatin was 3435 cm-1 (amide A), 2920 cm-1 (amide B), 1635 cm-1 (amide I), 1404 cm-1 (amide II), and 1036 cm-1 (amide III). The wave number absorption of amide III of gelatin is smaller than the one of collagen, because gelatin is in form of single helix, not triple helix. The wet scales derived and dried scales derived gelatin show the moisture content of 15.0% and 13.7%, and yield of 2.33% and 2.43%, .respectively. For both samples, the pH value was 7. Key words : gelatin, fish scales, molecule structure, moisture, yield, pH Abstrak Salah satu dari molekul protein sisik ikan adalah gelatin larut air. Gelatin sisik ikan dapat menjadi pengganti terbaik dari gelatin komersial yang tersedia yang berasal dari babi dan sapi. Tujuan dari penelitian ini adalah untuk menentukan struktur molekul gelatin yang diekstrak dari sisik ikan laut menggunakan Analisis FTIR (Fourier Transform Infrared), dan untuk mendapatkan kadar air, pH dan rendemen gelatin. Sampel disiapkan dari sisik basah dan sisik kering. Adapun standar gelatin, gelatin dari kedua sampel ditandai dengan beberapa jenis gugus amida. Kedua sampel gelatin sedikit berbeda dalam penyerapan panjang gelombang untuk amida A, B, I, II dan III yang menunjukkan ketidakstabilan kelompok fungsional yang dapat mempengaruhi viskositas dan kekuatan gel. Untuk gelatin sisik basah, panjang gelombang serapan ditemukan pada 3412 cm-1 (amida A), 2421 cm-1 (amida B), 1653 cm-1 (amida I), 1400 cm-1 (amida II), and 1001 cm-1 (amida III), sedangkan untuk gelatin sisik kering adalah 3435 cm-1 (amida A), 2920 cm-1 (amida B), 1635 cm-1 (amida I), 1404 cm-1 (amida II), and 1036 cm-1 (amida III). Panjang gelombang serapan amida III pada gelatin lebih kecil dibanding kolagen, sehingga gelatin berbentuk single helix, bukan triple helix. Gelatin sisik basah dan sisik kering mengadung kadar air 15,0% dan 13,7%, rendemen 2,33% and 2,43%, secara berturut-turut. Untuk kedua sampel memiliki nilai pH 7. Key words : gelatin, sisik ikan, struktur molekul, kadar air, rendemen, p