On the Role of Long-Chain Aldehydes in Mammalian Plasmalogen Biosynthesis

Abstract: [1-³H, 1-¹⁴C]Palmitaldehyde(³H:¹⁴C= 15) was injected intracerebrally to 18-day-old rats and incorporation of radioactivity into brain lipids was followed over a 24-h period. The substrate was metabolized primarily by oxidation to palmitic acid with loss of tritium and, to a lesser extent, by reduction to hexadecanol. The alkyl moieties of the ethanolamine phospholipids showed considerably lower ³H:¹⁴C ratios than the substrate, indicating a substantial participation in ether lipid synthesis by tritium-free alcohols derived from ¹⁴C-labeled fatty acids. Virtually no ³H radioactivity was found in alkenyl moieties, indicating stereospecificity of both reduction of aldehyde and dehydrogenation of alkyl to alkenyl glycerolipid. The data are consistent with the general concept that plasmalogen biosynthesis proceeds exclusively through fatty alcohols and alkyl glycerolipids and that fatty aldehydes cannot be utilized directly.     

Influence of External pH and Fermentation Products on Clostridium acetobutylicum Intracellular pH and Cellular Distribution of Fermentation Products

Clostridium acetobutylicum ATCC 824 cells harvested from a phosphate-limited chemostat culture maintained at pH 4.5 had intracellular concentrations of acetate, butyrate, and butanol which were 13-, 7-, and 1.3-fold higher, respectively, than the corresponding extracellular concentrations. Cells from a culture grown at pH 6.5 had intracellular concentrations of acetate and butyrate which were only 2.2-fold higher than the respective external concentrations. The highest intracellular concentrations of these acids were attained at ca. pH 5.5. When cells were suspended in anaerobic citrate-phosphate buffer at pH 4.5, exogenous acetate and butyrate caused a concentration-dependent decrease in the intracellular pH, while butanol had relatively little effect until the external concentration reached 150 mM. Acetone had no effect at concentrations up to 200 mM. These data demonstrate that acetate and butyrate are concentrated within the cell under acidic conditions and thus tend to lower the intracellular pH. The high intracellular butyrate concentration presumably leads to induction of solvent production, thereby circumventing a decrease in the intracellular pH great enough to be deleterious to the cell.     

Microbial Fermentation of Rice Straw: Nutritive Composition and In Vitro Digestibility of the Fermentation Products

Rice straw was fermented with Cellulomonas sp. and Alcaligenes faecalis. Microbial cells and undigested residue, as well as chemically treated (NaOH or NH₄OH) and untreated straws, were analyzed for nutrient composition and in vitro digestibility. In a typical fermentation, 75% of the rice straw substrate was digested, and 18.6% of the total substrate weight that disappeared was recovered as microbial protein. The microbial cell fraction was 37% protein and 5% crude fiber; the residue was 12% protein and 45% crude fiber. The microbial protein amino acid profile was similar to alfalfa, except for less cysteine. The microbial cells had more thiamine and less niacin than Torula yeast. In vitro digestibility of the microbial protein was 41.2 to 55%; that of cellulose was 52%.     

On the Origin of Language

Thomas Sebeok and Noam Chomsky are the acknowledged founding fathers of two research fields which are known respectively as Biosemiotics and Biolinguistics and which have been developed in parallel during the past 50 years. Both fields claim that language has biological roots and must be studied as a natural phenomenon, thus bringing to an end the old divide between nature and culture. In addition to this common goal, there are many other important similarities between them. Their definitions of language, for example, have much in common, despite the use of different terminologies. They both regard language as a faculty, or a modelling system, that appeared rapidly in the history of life and probably evolved as an exaptation from previous animal systems. Both accept that the fundamental characteristic of language is recursion, the ability to generate an unlimited number of structures from a finite set of elements (the property of ‘discrete infinity’). Both accept that human beings are born with a predisposition to acquire language in a few years and without apparent efforts (the innate component of language). In addition to similarities, however, there are also substantial differences between the two fields, and it is an historical fact that Sebeok and Chomsky made no attempt at resolving them. Biosemiotics and Biolinguistics have become two separate disciplines, and yet in the case of language they are studying the same phenomenon, so it should be possible to bring them together. Here it is shown that this is indeed the case. A convergence of the two fields does require a few basic readjustments in each of them, but leads to a unified framework that keeps the best of both disciplines and is in agreement with the experimental evidence. What is particularly important is that such a framework suggests immediately a new approach to the origin of language. More precisely, it suggests that the brain wiring processes that take place in all phases of human ontogenesis (embryonic, foetal, infant and child development) are based on organic codes, and it is the step-by-step appearance of these brain-wiring codes, in a condition that is referred to as cerebra bifida, that holds the key to the origin of language.     

End Products of Glucose Fermentation by Brochothrix thermosphacta

Anaerobically, Brochothrix thermosphacta fermented glucose primarily to l-lactate, acetate, formate, and ethanol. The ratio of these end products varied with growth conditions. Both the presence of acetate and formate and a pH below about 6 increased l-lactate production from glucose. Small amounts of butane-2,3-diol were also produced when the pH of the culture was low (相似文献   

放线菌JXJ-45固体发酵产物化学成分研究

通过对放线菌JXJ-45菌株固体发酵物的初步分离纯化,得到3个化合物,由波谱解析鉴定为:2,6-二甲基-2,6-二羟基-庚-4-酮(1),N-[2-(4-羟苯基)-乙基]乙酰胺(2),熊果苷(3).化合物2首次在放线菌中发现,化合物3首次在微生物中发现,是国际公认的高效祛斑美白剂.     

天然真菌与人工发酵制品对免疫系统的影响研究概况

整理分析有关真菌及其生物技术制品生物活性的研究文献,发现真菌类中药资源丰富、品种繁多、成分复杂、药理作用广泛。目前已被动物实验或临床研究证实具有显著生物活性的主要成分是多糖类、三萜类、核苷类以及多肽类等天然化合物。尤其是作为真菌细胞结构物质的高分子多糖体对机体免疫系统具有显著的影响。如在保护机体免疫器官、增加免疫器官重量,以及对单核吞噬细胞系统、T细胞、B细胞、红细胞、NK细胞、LAK细胞、补体系统、白细胞介素、干扰素、集落刺激因子、肿瘤坏死因子及一氧化碳等多项或单项免疫功能具有显著的增强或调节作用。在抗病毒与抗肿瘤免疫等方面显示出自身特点和优势。虽然也有一些真菌及其提取物被证明对机体免疫功能具有显著的、与药物剂量相关的抑制作用,但并未发现对机体免疫器官或免疫细胞有任何的毒副反应。作者拟将20年来有关真菌及其提取物对机体免疫系统的影响研究文献进行了整理,并按免疫功能分类进行了综述,对相关问题在文后还作了讨论,以期为真菌类药物在医学上进行深入的临床研究与应用提供思路。