MYCOLOGICAL SYNTHESIS OF FAT FROM WHEY. I. PRELIMINARY STUDIES WITH STATIONARY CULTURES

SUMMARY: Forty mould species, 30 of which were from the genera Aspergillus, Penicillium, Fusarium and Mucor , were examined for their ability to utilize the lactose in whey and to produce fat in the mycelium in stationary cultures.
In terms of lactose consumed and weight of mycelial felt produced the most promising species were A. ustus, P. frequentans, P. oxalicum and P. notatum. The first three of these warrant further study as fat producers.     

米曲霉中的一种新病毒与其它真菌病毒的血清型比较

自α-淀粉酶生产菌米曲霉Aspergillus oryzae 3800中找到直径20～24nm的等轴病毒颗粒(AoV),病毒具有典型核蛋白吸收峰,最大E258,最小E242,E260/280=1.36,沉降系数为45S,一个电泳组分,毒粒对氯仿敏感,细胞内含量低,病毒核酸电泳一个组分,地衣酚反应阳性,SDS-不连续聚丙烯酰胺凝胶电泳解离病毒得到分子量为17,800道尔顿的一个主要衣壳多肽。 AoV与小麦全蚀病菌病毒(GgV)的几个衣壳多肽及分子量不同的分离物间有共同的抗原性,而与产黄青霉病毒和同属的黑曲霉病毒不同,这是真菌寄主分类地位较远的病毒间有共同抗原性的不常见例子。     

STUDIES ON PROTEIN SYNTHESIS IN TOMATO COTYLEDONS AND LEAVES. II. INTERMEDIATE STAGES OF PROTEIN SYNTHESIS

1. The activities of RNase, ATPase and proteolytic enzymes inextractsof tomato leaves have been investigated with regardto detrimentaleffects on protein synthesis. The use of coppersulphate asan inhibitor of RNase is described.
2. The effectof microbial contamination on amino acid uptake hasbeen studiedin relationship with cell-free systems, and thehigh activitynoted underlines the necessity for aseptic procedures.
3. Methodsfor the preparation of cell-free systems capable ofamino acidactivation and incorporation into protein in an asepticenvironmentare discussed.

¹Present address: Dept. of Horticultural Science, Universityof Wisconsin, Madison, Wisconsin, U.S.A.     

HISTOLOGICAL STUDIES ON THE COLEOPTILE. II. COMPARATIVE VASCULAR ANATOMY OF COLEOPTILES OF AVENA AND TRITICUM

The vascular bundles in the uppermost 1-4 mm of the coleoptiles of 9 varieties of Avena sativa, and also of Avena fatua L., all terminate essentially vertically with a small “cap” of tracheary elements. In Triticum vulgare Vill., by contrast, they terminate with a horizontal or downward-pointing section. This brings the two bundles more or less together and may result in their complete fusion, usually with a short vascular extension. In both genera the bundles contain one or more series of apparently active, undifferentiated cells. In the mature embryos the bundles are entirely procambial in nature, but xylem differentiation begins rapidly upon germination and proceeds towards the tip, which is reached by the time the coleoptile is 1.5 mm long; thereafter it proceeds basipetally and it may continue at the base after elongation has ceased there. The differentiation of stomata also appears to proceed basipetally. It may be deduced that the coleoptile cannot form lignin while in the embryo but begins to do so upon germination. Parallels are brought out between auxin production first by the endosperm and then by the tip, on the one hand, and lignification in the xylem and in the stomata, on the other.     

COMPARATIVE STUDIES ON GLUTAMYL-tRNA SYNTHETASES ISOLATED FROM CYTOPLASM AND MITOCHONDRIA OF CALF BRAIN

Preparations of glutamyl-tRNA synthetase (EC 6.1.1.17) were isolated from cytoplasm and mitochondria of calf brain and purified by 14 and 9.5 times respectively. The effect of pH and that of the concentration of basic incubation mixture components on glutamyl-tRNA formation were estimated. The two preparations showed differences in response to optimum ration of Mg²⁺/ATP which is 6 for cytoplasmic system and 1 for mitochondrial system in aminoacylation reaction and a considerable difference in sensibility to concentration change of monovalent cations. Dithiotreitol not only protected both enzymatic preparations against thermal inactivation but even increased their activity.     

COMPARATIVE STUDIES ON MITOCHONDRIA ISOLATED FROM NEURON-ENRICHED AND GLIA-ENRICHED FRACTIONS OF RABBIT AND BEEF BRAIN

Fractions enriched in neuronal and glial cells were obtained from dispersions of whole beef brain and rabbit cerebral cortex by large-scale density gradient centrifugation procedures. The fractions were characterized by appropriate microscopic observation. Mitochondria were then isolated from these fractions by differential centrifugation of their homogenates. The two different types of mitochondria were characterized with respect to certain enzyme activities, respiratory rate, rate of protein synthesis, and their buoyant density in sucrose gradients. The mitochondria from the neuron-enriched fraction were distinguished by a higher rate of incorporation of amino acids into protein, higher cytochrome oxidase activity, and a higher buoyant density in sucrose density gradients. Mitochondria from the glia-enriched fraction showed relatively high monoamine oxidase and Na⁺- and K⁺-stimulated ATPase activities. The rates of oxidation of various substrates and the acceptor control ratios did not differ appreciably between the two types of mitochondria. The difference in the buoyant density of mitochondria isolated from the neuron-enriched and glia-enriched cell fractions was utilized in attempts to separate neuronal and glial mitochondria from the mixed mitochondria obtained from whole brain homogenates in shallow sucrose gradients. The appearance of two peaks of cytochrome oxidase, monoamine oxidase, and protein concentration in such gradients shows the potential feasibility of such an approach.     

STUDIES ON POLYSACCHARIDES FROM THREE EDIBLE SPECIES OF NOSTOC (CYANOBACTERIA) WITH DIFFERENT COLONY MORPHOLOGIES: COMPARISON OF MONOSACCHARIDE COMPOSITIONS AND VISCOSITIES OF POLYSACCHARIDES FROM FIELD COLONIES AND SUSPENSION CULTURES

Hot water-soluble polysaccharides were extracted from field colonies and suspension cultures of Nostoc commune Vaucher, Nostoc flagelliforme Berkeley et Curtis, and Nostoc sphaeroides Kützing. Excreted extracellular polymeric substances (EPS) were isolated from the media in which the suspension cultures were grown. The main monosaccharides of the field colony polysaccharides from the three species were glucose, xylose, and galactose, with an approximate ratio of 2:1:1. Mannose was also present, but the levels varied among the species, and arabinose appeared only in N. flagelliforme. The compositions of the cellular polysaccharides and EPS from suspension cultures were more complicated than those of the field samples and varied among the different species. The polysaccharides from the cultures of N. flagelliforme had a relatively simple composition consisting of mannose, galactose, glucose, and glucuronic acid, but no xylose, as was found in the field colony polysaccharides. The polysaccharides from cultures of N. sphaeroides contained glucose (the major component), rhamnose, fucose, xylose, mannose, and galactose. These same sugars were present in the polysaccharides from cultures of N. commune, with xylose as the major component. Combined nitrogen in the media had no qualitative influence on the compositions of the cellular polysaccharides but affected those of the EPS of N. commune and N. flagelliforme. The EPS of N. sphaeroides had a very low total carbohydrate content and thus was not considered to be polysaccharide in nature. The field colony polysaccharides could be separated by anion exchange chromatography into neutral and acidic fractions having similar sugar compositions. Preliminary linkage analysis showed that 1) xylose, glucose, and galactose were 1→4 linked, 2) mannose, galactose, and xylose occurred as terminal residues, and 3) branch points occurred in glucose as 1→3,4 and 1→3,6 linkages and in xylose as a 1→3,4 linkage. The polymer preparations from field colonies had higher kinematic viscosities than those from correspondingsuspension cultures. The high viscosities of the polymers suggested that they might be suitable for industrial uses.     

HYBRIDIZATION STUDIES WITH SPECIES OF CYNODON FROM EAST AFRICA AND MALAGASY

A collection of 198 accessions of Cynodon from East Africa and Malagasy was grown in uniform nurseries at Stillwater, Okla., and classified morphologically, studied cytologically, and tested for crossability in hybridization studies. The following taxa were recognized: C. arcuatus, C. plectostachyus, C. aethiopicus, C. nlemfuensis var. nlemfuensis, C. nlemfuensis var. robustas, C. dactylon var. aridus, C. dactylon var. coursii, and C. dactylon var. dactylon. The magnitude of barriers to gene flow was estimated by ease of hybridization and by sterility of the hybrids obtained. C. arcuatus and C. plectostachyus are well isolated from all other species in the genus. The others are sufficiently related that they may be intercrossed. The barriers to gene flow vary demonstrably in strength between different combinations of taxa. The magnitude of a barrier required to establish species limits is, perhaps, more a matter of subjective opinion than a scientific conclusion. It was concluded that no completely satisfactory classification of the genus is possible. The system adopted was a compromise between classical morphological concepts of species, the biological concept of species, and pragmatic utility.     

COMPARATIVE STUDIES ON VARIOUS CALLUSES AND CROWN GALL OF JERUSALEM ARTICHOKE II. SOME BIOCHEMICAL PROPERTIES

A callus isolated from Jerusalem artichoke tuber was found tohave much more cell wall material and tyrosinase activity thanthe original tuber, and its dry weight was dependent on thesucrose concentration in the culture medium. All calluses anda crown gall tested contained no detectable inulin. Even thoughdifferent cultures were widely different in their dry weight,this was closely related to their total hexose content, andthe latter in turn was proportional to their free hexose content. (Received January 18, 1967; )     

鲫鱼、草鱼离体肠道利用酪氨酸和脯氨酸合成蛋白质与脂肪的研究

该试验采用同位素示踪技术和肠道离体灌流模型分别测定了鲫鱼、草鱼肠粘膜中结合在蛋白质与脂类中的酪氨酸、脯氨酸的量。结果表明：用于合成脂肪的酪氧酸和脯氯酸比例在鲫鱼和草鱼均极显著高于用于合成蛋白质的相应氨基酸比例（P〈0．01）,但草鱼用于合成脂肪的酪氨酸和脯氨酸比例均显著高于鲫鱼（P〈0．05）。在酪氨酸各浓度组中鲫鱼肠道利用其合成蛋白质与脂肪的绝对量几乎都高于草鱼,但从相对量上看,鲫鱼利用酪氨酸合成蛋白质和脂肪的能力显著不如草鱼（P〈0．05）对于每一浓度组的脯氨酸,鲫鱼肠道利用其合成蛋白质的绝对量和相对量均显著高于草鱼（P〈0．05）,说明鲫鱼利用脯氯酸合成蛋白质的能力显著高于草鱼;但从相对量来看,除了1．0mmol／L试验组外,鲫鱼利用脯氢酸合成脂肪的能力显著低于草鱼（P〈0．05）。     

海洋卡盾藻与中肋骨条藻和锥状斯氏藻种间竞争研究

研究了不同起始细胞密度与硅酸盐浓度对海洋卡盾藻(Cm)与中肋骨条藻(Sc)及锥状斯氏藻(St)之间种间竞争的影响,利用竞争抑制参数对相互间的竞争关系进行了分析,并引入体积竞争抑制系数的概念。结果表明:海洋卡盾藻的环境容量不受起始细胞密度(100—3600cells/mL)的影响,但随着起始接种密度的增加,达到最大细胞密度和进入稳定生长期的时间均提前。在硅缺乏的条件下,中肋骨条藻仍能保持一定生长,并能在与海洋卡盾藻之间的种间竞争中保持数量优势,但硅酸盐浓度的增加有利于其种间竞争。初始细胞密度和接种比例对3种赤潮藻类之间的种间竞争影响明显,总体来说海洋卡盾藻在竞争中处于劣势。当海洋卡盾藻细胞密度远远高于中肋骨条藻时(Cm:Sc=6:1),海洋卡盾藻才能在与中肋骨条藻的竞争中取胜;而在与海洋卡盾藻共培养条件下,锥状斯氏藻具有一定竞争优势,其对海洋卡盾藻的体积抑制系数(α’)是后者(β’)的27—100倍。但在所有处理中均没有绝对优胜者,竞争结果都会出现不稳定的平衡状态。       

野生大家鼠和实验大白鼠血红蛋白和乳酸脱氢酶同工酶的比较研究

本文对野生大家鼠（Ｒａｔｕｓｎｏｒｖｅｇｉｃｕｓ）和Ｗｉｓｔａｒ品系实验大白鼠的血红蛋白（Ｈｂ）及组织的乳酸脱氢酶（ＬＤＨ）同工酶进行了电泳分析,结果表明,两种鼠均表现了Ｈｂ的多态性,其中ＨｂＩ型都含有８个成分,各成分的泳动率相同。两种鼠的心脏ＬＤＨ同工酶都含有ＬＤＨ１,ＬＤＨ２,ＬＤＨ３和ＬＤＨ５,而且各谱带泳动率相近似,其余组织ＬＤＨ谱带泳动率有明显的差异,表现了组织和种（或品系）的特异性。从电泳图谱上发现Ｗｉｓｔａｒ大鼠ＬＤＨ５（Ａ或Ｍ亚基纯合体）出现亚带,而ＬＤＨ１（Ｂ或Ｈ亚基纯合体）则未发现,可确定变异是由于Ａ或Ｍ亚基位点发生突变,出现等位基因而导致。对褐家鼠的ＬＤＨ４出现亚带也进行了讨论     

SENSORY AND INSTRUMENTAL EVALUATIONS OF TEXTURE IN CHEESES MADE FROM OVINE MILKS WITH DIFFERING FAT CONTENTS

The present study considers the influence of reducing the fat content of ovine milk on the sensory and instrumental texture characteristics of the resulting cheeses. Three manufacturing runs were performed. In each run three cheese batches were manufactured using milks with differing percentage fat contents (8%, 4%, and 2% fat). Analysis of cheese samples was performed at 60, 90, and 120 days of ripening.
The instrumental method used to evaluate cheese texture was uniaxial compression at constant speed, taking readings of stress, strain, and modulus of elasticity (E). Statisticalanalysis revealed differences forboth the differentfat contents and the ripening times considered. Instrumental parameter values increased with lower cheese fat contents; with a 20% reduction in the fat to dry matter content from full-fat to reduced-fat cheeses, resulting in a 35% increase in maximum stress and in the slope of the stress-strain curve at the end of ripening. The greatest sensory differences between samples were recorded for firmness.     

COMPARISON OF THE GROWTH AND DIFFERENTIATION OF EPITHELIAL CELLS FROM NORMAL AND HYPERPLASTIC LENSES OF THE CHICK: STUDIES OF IN VITRO CELL CULTURES

Epithelial cells from hyperplastic lenses of a strain of chicks (Hy-1) selected for high growth rate were dissociated and cultured in vitro and compared with lens epithelial cells from a normal strain (N) in similar conditions. The hyperplastic lens cells showed remarkable motility and adhesiveness after dissociation and formed cell aggregates of various sizes before attaching to the substrate, giving a rather low plating efficiency. The lens structures (lentoid bodies) developed in partially confluent cultures of Hy-1 cells at least three days earlier than those in the cultures from normal control cells, in which the lens structures developed only after the cultures reached confluence. The results of culture at low cell density showed that the Hy-1 cell population consisted of at least two cell types different from each other in growth capacity. These striking differences in in vitro behaviour of dissociated cells from normal and hyperplastic lens epithelia and the results of clonal culture are discussed in relation to the possible mechanisms of abnormal morphogenesis and growth which are likely to be involved in the development of the hyperplastic lens in situ .