Antimetabolic activities of 2-fluoro-L-histidine.

2-Fluoro-L-Histidine inhibits protein synthesis in various cell cultures, as measured by ³H-leucine incorporation. This histidine analog also inhibits the cytopathogenicity of a number of RNA and DNA viruses in primary and continuous cell cultures; it blocks the transformation of normal mouse (MO) cells by murine sarcoma virus, and partially suppresses the release of murine leukemia virus by a continuously infected mouse cell line (JLSV5). In human skin fibroblasts, it reduces the interferon-inducing capacity of poly(I)·poly(C). Inhibition of cell protein synthesis may be the common cause of the various effects. 4-Fluoro-L-histidine is essentially inert in all of the test systems examined.     

Limits and Sites of Lysinoalanine Formation in Lysozyme, α-Lactalbumin and αs1- and β-Caseins by Alkali Treatment

Lysinoalanine was determined by gas chromatography. Lysinoalanine formation in lysozyme depended on alkali concentration, pH, temperature and exposure time. The upper limits of lysinoalanine formation in lysozyme and α-lactalbumin were related to the number of lysine residues with a cystine disulfide bond in the adjacent position rather than the individual contents of these residues. In cases of α_sl- and β-caseins, the upper limits were related to the number of phosphoserine residues, regardless of their sequential relationship to lysine residues. Gel electrophoresis suggested that intermolecular cross-linking took place in the α-lactalbumin and caseins.     

Formulation and production of a blood-free and chemically defined virus production media for VERO cells

Vaccines provide effective protection against many infectious diseases as well as therapeutics for select pathologies, such as cancer. Many viral vaccines require amplification of virus in cell cultures during manufacture. Traditionally, cell cultures, such as VERO, have been used for virus production in bovine serum-containing culture media. However, due to concerns of potential adventitious agents present in fetal bovine serum (FBS), regulatory agencies suggest avoiding the use of bovine serum in vaccine production. Current serum-free media suitable for VERO-based virus production contains high concentrations of undefined plant hydrolysates. Although these media have been extensively used, the lack of chemical definition has the potential to adversely affect cell growth kinetics and subsequent virus production. As plant hydrolysates are made from plant raw materials, performance variations could be significant among different lots of production. We developed a chemically defined, serum-free medium, OptiVERO, which was optimized specifically for VERO cells. VERO cell growth kinetics were demonstrated to be equivalent to EMEM-10% FBS in this chemically defined medium while the plant hydrolysate-containing medium demonstrated a slower doubling time in both two-dimensional (2D) and 3D cultures. Virus production comparisons demonstrated that the chemically defined OptiVERO medium performed at least as good as the EMEM-10%FBS and better than the plant hydrolysate-containing media. We report the success in using recombinant proteins to replace undefined plant hydrolysates to formulate a chemically defined medium that can efficiently support VERO cell expansion and virus production.     

Morphological changes in CHO and VERO cells treated with T-2 mycotoxin. Correlation with inhibition of protein synthesis

Exposure of Chinese hamster ovary and African green monkey kidney cells to T-2 mycotoxin resulted in several morphological changes which were related to inhibition of protein synthesis, the basic in vitro mechanism of action of the toxin. These changes, which occurred in both cell types, included disassociation of polysomes and mitochondrial cristae alterations. In addition, CHO cells displayed membrane bleb formations similar to those found in CHO cells after exposure to established inhibitors of protein synthesis, puromycin and anisomycin. Blebs could be either a result of protein synthesis inhibition or a non-specific early pathological response. Bleb formations were not observed in VERO cells under any experimental condition.     

Previously published ethno-pharmacological reports reveal the potentiality of plants and plant-derived products used as traditional home remedies by Bangladeshi COVID-19 patients to combat SARS-CoV-2

Several plants have traditionally been used since antiquity to treat various gastroenteritis and respiratory symptoms similar to COVID-19 outcomes. The common symptoms of COVID-19 include fever or chills, cold, cough, flu, headache, diarrhoea, tiredness/fatigue, sore throat, loss of taste or smell, asthma, shortness of breath, or difficulty breathing, etc. This study aims to find out the plants and plant-derived products which are being used by the COVID-19 infected patients in Bangladesh and how those plants are being used for the management of COVID-19 symptoms. In this study, online and partially in-person survey interviews were carried out among Bangladeshi respondents. We selected Bangladeshi COVID-19 patients who were detected Coronavirus positive (+) by RT-PCR nucleic acid test and later recovered. Furthermore, identified plant species from the surveys were thoroughly investigated for safety and efficacy based on the previous ethnomedicinal usage reports. Based on the published data, they were also reviewed for their significant potentialities as antiviral, anti-inflammatory, and immunomodulatory agents. We explored comprehensive information about a total of 26 plant species, belonging to 23 genera and 17 different botanical families, used in COVID-19 treatment as home remedies by the respondents. Most of the plants and plant-derived products were collected directly from the local marketplace. According to our survey results, greatly top 5 cited plant species measured as per the highest RFC value are Camellia sinensis (1.0) > Allium sativum (0.984) > Azadirachta indica (0.966) > Zingiber officinale (0.966) > Syzygium aromaticum (0.943). Previously published ethnomedicinal usage reports, antiviral, anti-inflammatory, and immunomodulatory activity of the concerned plant species also support our results. Thus, the survey and review analysis simultaneously reveals that these reported plants and plant-derived products might be promising candidates for the treatment of COVID-19. Moreover, this study clarifies the reported plants for their safety during COVID-19 management and thereby supporting them to include in any future pre-clinical and clinical investigation for developing herbal COVID-19 therapeutics.     

病毒疫苗制备用不同核型VERO细胞系在裸鼠体内致癌/致瘤性的系统实验研究

生产疫苗用细胞系可能具有致瘤性,一些常用的细胞系需要检查不同代次有无致癌性。在建立传代细胞种子库与工作库基础上,对研制生产病毒活疫苗所用8株VERO细胞系在219只裸鼠进行了致癌(瘤)实验。本研究结果表明,VERO细胞染色体核型可发生变异,亚四倍体JA株与超二倍体KA株具有强的致癌性,不能用于致弱活病毒疫苗制备,但可替代HeLa细胞系用作恶性肿瘤阳性对照细胞。筛出无致瘤性的YB、dC、M和JB株亚二倍体VERO细胞系,可替代BHK-21细胞用于狂犬病减毒活疫苗制备。VERO细胞系染色体遗传相对稳定。不同代次变化不大。研究发现细胞染色体遗传特征决定致瘤性质并具有种属特异性,不同核型细胞致瘤性不同,细胞染色体数目变异大小和致癌性成正相关,通过体内外交替选育可在裸鼠体内快速选育成功高变异率肿瘤细胞系。高变异率HeLa或VERO细胞系移植于裸鼠可能产生恶性横纹肌样瘤。因此,应当强调疫苗生产用细胞系致瘤性评价的重要性。     

Nuclear pore complex oxalate binding protein p62: its expression on oxalate exposure to VERO cells

Oxalate rich stones are the most common among the various stones. Oxalate binding protein plays a vital role in the transport of oxalate. Nuclear pore complex (NPC) contains a protein of molecular weight 62 kDa and it has maximum oxalate binding activity. The physiological significance of the presence of oxalate binding protein in the NPC is not well understood. In order to study its function, the expression of this protein during oxalate stress condition and the morphological changes on oxalate exposure to synchronized VERO cells have been determined. VERO cells were synchronized at different stages of cell cycle using cell cycle blockers and expression of the NPC p62 was assessed using enzyme linked immunosorbent assay (ELISA) technique with p62 antibody (MAb 414). Expression of NPC p62 was more pronounced in 1.0 mM oxalate concentration in mitotic phase than in S phase, suggesting cell cycle dependency. During oxalate exposure there is cell aggregation and complete degeneration of cell morphology occurs, which in turn lead to the expression of certain genes, including the NPC oxalate binding protein p62. Thus, oxalate induces degeneration of cells (may be due to the lipid peroxidation) and leads to the expression of NPC oxalate binding protein and the expression is of cell cycle dependent manner.     

Production of Shiga toxin and a cytolethal distending toxin (CLDT) by serogroups of Shigella spp.

Abstract 56 strains of Shigella including 12 Shigella dysenteriae (serotypes 1, 2, 9, 11 and 12), 23 Shigella flexneri (serotypes 1, 2, 3, 4, 6, var. X and var. Y), 19 Shigella boydii (serotypes 1, 2, 4, 5, 7, 11, 13, 14, 15 and 18), and 2 Shigella sonnei were screened for their ability to produce both classic Shiga toxin and a new heat-labile cytolethal distending toxin (CLDT). Whereas extracellular Shiga toxin was only detectable in filtrates of five S. dysenteriae type 1 strains, CLDT was produced by four strains of S. dysenteriae type 2 and an isolate of S. boydii type 7. No cytotonic enterotoxins similar to Escherichia coli LT were observed in this study. None of the S. flexneri or S. sonnei isolates tested were found to produce extracellular cytotoxic factors. The Shiga toxin produced by the S. dysenteriae type 1 was neutralizable by anti-toxin to verotoxin 1 of E. coli O157 : H7. The Shigella CLDT was neutralizable by antisera prepared to a CLDT-producing E. coli O55 : H4.     

Fluoroimidazoles as antiviral agents and inhibitors of polynucleotide biosynthesis.

Some recent studies relating the effects of individual housing (isolation) and group housing to behavior, physiology and neurochemistry in laboratory rats and mice are reviewed and these accounts related to comparable information derived from experiments employing “social stresses” e.g. subjecting the animal to defeat. The data is discussed in relation to the problem of whether individual housing constitutes a “stress” (in terms of adrenocortical and adrenal medullary functioning) in these species, as it appears to do in primates. In spite of the large number of papers which ascribe the behavioral and endocrine changes obtained in isolation versus grouping comparisons to the effects of “the isolation-induced stress syndrome”, it is concluded that, in terms of adrenal function, there is little evidence that isolation $\text{per}$$\text{se}$ constitutes a stress in rats and mice, although there is some evidence that adrenocortical reactivity is increased by housing animals in this manner. It should be noted that the wild progenitor of the laboratory strains of house mouse often appears to evidence territoriality. The view is advanced that the isolated condition in male mice may result in changes characteristic of territorial dominance. This may represent a mechanism for inducing social or territorial stability in this species. It appears that experiments involving physical isolation in laboratory rodents are unlikely to provide good models for the effects of “social deprivation” in man. It is thought that more studies employing measurement of hormone titers in biological samples, obtained as a result of non-stressful procedures, will lead to a clearer understanding of the effects seen in isolation versus grouping studies. Organ weight studies often appear to be very misleading, particularly in female rodents. It is also hoped that other studies will concern themselves with effects of isolation with respect to other social cues in rodents including odors and ultrasound.