THE DISTRIBUTION AND SIGNIFICANCE OF DIFFERENT SPECIES OF FAECAL STREPTOCOCCI IN BACON FACTORIES

SUMMARY: A survey has been made of the numbers and types of group D faecal streptococci in three bacon factories. Although Streptococcus faecium , normally present in the gut of the pig and isolated from spoiled canned hams, was found, it was often outnumbered by Strep. faecalis , an indicator of human faecal contamination which is rare in the pig. The rôle of these two organisms in ham spoilage is discussed. The value of thallous acetate-tetrazolium-glucose agar for isolating and distinguishing these organisms has been demonstrated, and it is suggested that the method may have more general application where it is necessary to differentiate between faecal streptococci of human and animal origin.     

THE VALUE OF THE ASSOCIATION ESCHERICHIEAE-GROUP D STREPTOCOCCI IN THE DIAGNOSIS OF CONTAMINATION IN FOODS

SUMMARY: The tests for faecal contamination in foods, based on 'indicator species', should be reconsidered for the following reasons. First, in Europe, Escherichia coli is regarded as a specific index of such contamination; but, apparently through the use of antibiotics, the proportion of human faeces containing Klebsiella has risen from 5.2% in 1947 to 48.4% in 1956–7. Moreover, E. coli and other coli-aerogenes organisms may be absent from the gut of certain animals, notably the pig. Second, while the usual methods of counting coli-aerogenes bacteria do not permit the isolation of strains which ferment lactose slowly or not at all (i.e. paracolons), these occur in 35.6% of samples of human faeces. Further, the recommended methods of detecting such strains are not wholly satisfactory. Third, the origin of the coli-aerogenes bacteria is uncertain.
It is thus necessary to consider other organisms which normally inhabit the intestinal tract of humans and other animals. As to Clostridium perfringens , its source is doubtful, for it may come from faeces or from soil, and many foods contain only soil strains. The group D streptococci, on the other hand, are excellent indicators of faecal contamination. They are constant or frequent in the intestines of man and animals, and often more numerous there than coli-aerogenes bacteria. Their specificity as an index of faecal contamination is high and their investigation is easy with the selective media now available. Associated with the coli-aerogenes bacteria, they justify the diagnosis of faecal contamination in a foodstuff.     

SUBCELLULAR DISTRIBUTION OF DOPAMINE-β-HYDROXYLASE AND INHIBITORS IN THE HIPPOCAMPUS AND CAUDATE NUCLEUS IN SHEEP BRAIN

—The enzyme dopamine-β-hydroxylase (EC 1.14.17.1) which converts dopamine to noradrenaline was found to be present in substantial amounts in sheep brain hypothalamus and caudate nucleus and was located to the synaptic vesicle fractions in these two brain regions by subcellular fractionation. This dopamine-β-hydroxylase was associated with paniculate matter in these two brain regions since it was resistant to solubilization with butan-1-ol and 0.1% Triton X-100. As highly significant levels of dopamine-β-hydroxylase were present in the caudate nucleus, factors other than a simple lack of this enzyme must operate to maintain the low levels of noradrenaline and high levels of dopamine in the caudate nucleus. Purified adrenal dopamine-β-hydroxylase was substantially inhibited by two factors prepared from sheep brain hypothalamus and caudate nucleus. These were found to be cupric ions and a sulphydryl inhibitor. High levels of the sulphydryl inhibitor of dopamine-β-hydroxylase were found in synaptosomal fractions from sheep brain hypothalamus and caudate nucleus and the levels were comparable in both regions. Upon subfractionation of a synaptosome-containing fraction from the hypothalamus, the inhibitor was located predominantly in the soluble fraction, although there were significant levels in the synaptic vesicle fraction. Therefore, the sulphydryl inhibitor must be considered as a possible regulator of dopamine-β-hydroxylase activity. Free cupric ion concentrations as low as 2·5 μM were found to inhibit purified adrenal dopamine-β-hydroxylase in vitro and the concentration of copper in the soluble tissue component of hypothalamus and caudate nucleus was well above this minimal copper concentration. The percentage content of soluble copper in the caudate nucleus was significantly higher than in the hypothalamus. The importance of the soluble to particulate-bound ratio of copper in brain was shown in studies of the developing rat brain. A rapid increase in the level of copper in brain was found in the first 4 weeks but the level was constant by 2 months of age. The percentage of soluble copper, however, was maximal soon after birth and had declined to a constant figure by 2 months of age. A scheme for the regulation of dopamine-β-hydroxylase activity involving these factors is proposed.     

侗族九个红细胞血型系统和ABH分泌型的分布

报道了广西侗族的ABO、MNSs、Rhesus、Duffy、Kidd、P、Diego、Lewis和Xg等九种红细胞血型系统和ABH唾液分泌型的分布。共调查了201名父母均系侗族而彼此无血缘的学生,其中男116名,女85名。结果表明,广西侗族中ABO系统的r基因(0.6286)、MN系统的m基因(0.6294)、Duffy系统的Fy~a基因(0.9651)、Kidd系统的JK~a基因(0.4628)和Rhesus系统的CDe染色体(0.7532)等频率都很高,ABO系统的q基因(0.1672)、P系统的P_1基因(0.1333)和Lewis系统的Le~a基因(0.3232)等频率较低。MNSs系统的S基因(0.0124)频率很低,而MS染色体连锁率却为零。Xg系统的Xg~a基因频率(0.3746)与汉族和维吾尔族一样,处于低水平。Lewis系统的Le(a )表型者中发现八例是ABH唾液分泌型,但分泌的物质不是A便是B,而分泌H物质的唾液分泌型者全部都是Le(a-)型。六个民族间遗传距离分析表明,侗族与壮族在血缘上最近,其次是与朝鲜族、蒙古族、汉族相近,而与维吾尔族最远。     

THE PHYSIOLOGICAL AND SEROLOGICAL PROPERTIES OF STREPTOCOCCUS BOVIS AND RELATED ORGANISMS ISOLATED FROM CATTLE AND SHEEP

The physiological and serological properties of 153 strains of Streptococcus bovis isolated from cattle and sheep have been studied. With 12 specific antisera it was possible to type 75 of the isolates. Neither the fermentation of arabinose nor of raffinose was related to type specificity. The only strain fermenting mannitol was serologically distinct from all the other strains, and the type antigen was probably located on the cell wall whereas with the other 11 types it was capsular.
The distribution of these types in cattle and sheep has been determined together with their changes in individual cows sampled on three occasions over 18 months.     

海北藏系绵羊种群结构及其出栏方案最优化的探讨

配置畜群结构是管理畜牧生产最重要的工作之一。目前我国普遍存在着畜群结构不合理的现象。藏羊是我国第二大绵羊品种,其生产管理落后,种群结构普遍不合理。为组织合理生产,本文用系统分析的方法对藏羊种群结构进行了研究。首先,根据实地调查研究,作者构成了一个矩阵模型,以描述藏羊种群的性别年龄结构状态: N_(t+1)=AN_t-BU_t 其中AN_t反映羊群的自然变动情况,U_t是人为控制量。 然后,以最大羊产品收获为目标,以牧草资源和种群平衡态为限制条件,本文构造了一个线性规划模型,用以计算最优藏羊种群结构及其出栏方案; 除了给出模型这个研究种群结构问题的方法之外,本文使用线性规划模型,利用作者在青海省门源县风闸口地区调查测定的数据,通过计算机,算出了该地最优藏羊种群结构及其出栏方案。在最大能量收获的目标下。最优结构应为,67.80％的繁殖母羊,28.36％的后备母羊,3.84％的种公羊和后备种公 羊。相应出栏方案是每年秋季出栏全部羯羊羔和老弱羊,并且出栏33.17％的成年母羊。在这种方案下,按现有羊只生产能力,出栏率可提高到52.79％,平均从每百公斤牧草中收获合11.72千千卡能量或3.65公斤活重的羊产品。     

METHODS FOR THE ISOLATION OF FAECAL STREPTOCOCCI (LANCEFIELD GROUP D) FROM BACON FACTORIES

SUMMARY: Two methods have been developed for isolating and enumerating group D faecal streptococci from localities such as bacon factories where they are heavily outnumbered by other organisms. The first depends on presumptive counts in a Lab-Lemco-peptone-glucose broth (pH 6·0) containing 0·1% of thallous acetate with confirmation by streaking on tetrazolium agar. The other method involves direct plating on tetrazolium-glucose agar (pH 6·0) containing 0·1% of thallous acetate. On the tetrazolium medium differentiation can be made between Streptococcus faecalis and its variants zymogenes and liquefaciens and the other group D organisms, Strep. faecium, Strep. durans and Strep. bovis .     

鉴定猪,牛及绵羊肥大细胞的组织化学技术

研究证实Ｃａｒｎｏｙ液和中性缓冲福尔马林溶液（ＮＢＦ）是猪、牛及绵羊肥大细胞的优良的固定液,ＮＢＦ虽能很好地保存牛和绵羊的肥大细胞,但却阻断了猪的大多数肥大细胞、特别中肠粘膜肥大细胞（ＭＭＣ）及胸腺髓质肥大细胞（ＴＭＭＣ）对碱性染料的着染力。力苯胺蓝及阿尔辛蓝均为动物肥大细胞的优良染料,但阿尔辛蓝能使更多的肥大细胞着力。甲苯胺蓝及阿尔辛蓝均为动物肥大细胞的优良染料,但阿尔辛蓝能使理多的肥大细胞着染     

THE EXCHANGE OF PHOSPHATIDYLCHOLINE AND OF PHOSPHATIDYLINOSITOL IN SHEEP BRAIN

—The exchange of phospholipids between liposomes and brain mitochondria has been studied in the presence of pH 5·1 supernatant fluids derived from rat, guinea pig, sheep and ox brains. The exchange phenomenon was similar to that observed in liver and heart, but phosphatidylinositol and not phosphatidylcholine was the most rapidly exchanging phospholipid. The phosphatidylcholine exchange activity was purified 186-fold from sheep brain and the protein fraction contained two major and several minor protein species. The phosphatidylcholine and phosphatidylinositol exchange activities have been shown to have very similar molecular weights and isoelectric points. However, their behaviour in response to changes in liposomal surface charge suggested that separate proteins might be involved in stimulating the exchange of the two phospholipid classes.     

贵州汉族八个红细胞血型系统的分布

本文调查了贵州汉族八个红细胞血型系统的分布。结果表明P_1基因频率(0.1520)和Di~a。基因频率(0.0182)较低。其它系统的基因频率为P=0.2171、q=0.1858、r=0.5969、m=0.5400、n=0.4600、S=0.0478、s=0.9522、Jk~a=0.4633、Jk~b=0.5367、Fy~a=0.9367、Fy~b=0.0633。MNSs血型系统单倍型频率为MS=0.0301、NS=0.0177、Ms=0.5099、Ns=0.4423。Rh血型系统单倍型频率为R~1=0.5766、R~2=0.2508、R~0=0.0511、R~z=0.0421、r~’=0.0794。未发现MMSS、MNSS及Fy(a-)表现型。