In vitro construction of a recombinant adenovirus Ad2:Ad5

A hybrid virus containing the left half of the Ad5 genome and the right half of the Ad2 genome has been constructed by ligating together in vitro the BamHI.-A fragment of Ad5 (map co-ordinates 0–59.5) to the-SawHI-A fragment of Ad2 (map coordinates 59.5–100), and using this DNA to transfect susceptible cells. Viable progeny virus has been obtained which grows as well as the parental virus without any requirement for helper virus, and probably contains a hybrid hexon polypeptide consisting of the major part of the Ad5 hexon with an Ad2 carboxy terminus.     

Effects of pyrrol-carboxylic acid derivatives on the growth of coliphages.

Effects of 14 pyrrol-carboxylic acid derivatives and analogues (PY-compounds) on the growth of coliphage MS2 using E. coli E102 (Hfr) as the host were measured by the agar double-layer method. Enlargements of plaque size were observed with 7 PY-compounds but increase in plaque numbers was not induced. These enlargements of plaque size were specific to RNA coliphages MS2, GA and qbeta and not found with DNA coliphages delta AC and T4. Furthermore, the interaction between PY-compound PY-10 and the coliphage MS2 was dependent on the host bacterium (indicator strain). When E102 (Hfr) was used, the enlargement was marked, in the case of substrain W1895 (Hfr) it was less, while in the case of substrain W6 (F+) it was undetectable. The one-step growth of the phage MS2 and the production of intracellular phage MS2 were little affected by the PY-compound PY-10. However, the rate of one-step growth was increased in the early stage after infection. Accordingly, the enlargements of plaque size by the PY-compounds might be correlated with an increase in rate of release of phage particles.     

Nosema parkeri sp. n., a Microsporidan from the Argasid Tick, Ornithodoros parkeri Cooley

SYNOPSIS. Nosema parkeri sp. n. is described from nymphs and adults of the argasid tick, Ornithodoros parkeri Cooley, from a laboratory colony. Schizogonic and sporogonic stages are described from various tick tissues. Spores are binucleate, measuring 3.2 (3–4) × 1.9 (1.8–2.5) μm. Transmission is transovarial and transstadial. The parasite does not appear to affect adversely the development or reproduction of the tick. Dermacentor andersoni Stiles was experimentally infected. Attempts to infect Swiss mice by tick feeding or by injection of infected tick suspensions were unsuccessful. The microsporidan differs in structure from Encephalitozoon ixodis Weiser) and Nosema slovaca Weiser & Reháček, the only other microsporidans known from ticks.     

DNA Throughout the Single Mitochondrion of a Kinetoplastid Flagellate: Observations on the Ultrastructure of Cryptobia vaginalis (Hesse, 1910)

SYNOPSIS. Cryptobia vaginalis (Hesse 1910) occurs as long thin and short broad forms in the vagina of the gnathobdelliform leeches Haemopis sanguisuga (Linnaeus) and Hirudo medicinalis Linnaeus. Cytochemical staining for DNA and transmission electron microscopy of sectioned material indicate that in the thin forms the kinetoplast DNA (kDNA) is dispersed irregularly through the mitochondrial network ( pankinetoplastic condition) rather than concentrated in the adbasal region of the mitochondrion ( eukinetoplastic condition) as in trypanosomatids and most other kinetoplastid flagellates. Light-microscopic studies on the rare broad forms, however, suggest that these have conventional adbasal location of the kinetoplast. Binary fission appears to occur in the thin forms, suggesting that the dispersed kinetoplast is either highly polyenergid or lacks a genetic function. In other features of its microanatomy, C. vaginalis is a conventional kinetoplastid. The flagellate has an incomplete corset of pellicular microtubules which may have a role in the cortical contractility characteristic of the genus Cryptobia . Feeding is by pinocytosis of vaginal colloids through a microtubule-lined cytopharynx, possibly after binding to a prominent filament-coated preoral ridge. A pulsatile (contractile) vacuole is present and appears to be responsible for defecation as well as osmoregulation. Some individuals have elongate bacterial epibionts attached to the body in parallel with the cortical microtubules. All individuals have 2–8 spheroplast-like endobiotic bacteria in the prenuclear cytoplasm.     

Immune response to human influenza virus hemagglutinin expressed in Escherichia coli

Cloned DNA fragments coding for parts of strain WSN (H1N1) influenza virus hemagglutinin (HA) were fused to a bacterial leader DNA derived from the Escherichia coli trp operon. Fusion proteins produced consisted of 190 amino acids of trpLE' protein at the amino terminus, and HA amino acids, either 1-308, 1-396, or 1-548 (complete HA), at the carboxyl terminus. These proteins were expressed at high levels (10-20% of total protein) in E. coli starved for tryptophan. A CNBr fragment (HA1-211) was derived from HA-308. Each of the proteins was purified and used for immunizing mice and rabbits. The antibody produced was shown to bind to (i) the HA fusion proteins, (ii) detergent-treated viral HA, (iii) HA, on intact virions, and (iv) the HA on the surface of cells infected with influenza virus. This shows that the HA fusion proteins expressed in bacteria can elicit antibodies that recognize at least some determinants of the native viral HA, and probably could lead to development of an anti-influenza vaccine.     

Molecular cloning of unintegrated visna viral DNA and characterization of frequent deletions in the 3' terminus

Visna viral DNA, like other retroviral DNA, exists in two circular forms in infected cells. The larger probably contains two copies of the LTR, the smaller, one copy. Recombinant DNA techniques were used to clone unintegrated circular visna viral DNA in the lambda WES . lambda B vector. Circular visna viral DNA was digested with the restriction enzyme SstI, which yields a 9.2-kb viral DNA fragment containing 90% of the viral genome colinear with the restriction map of linear viral DNA. This fragment extends from a site about 900 bp from the left (5') end of the viral DNA molecule, through the 3' region, including U3 and R sequences at its right (3') end. The recombinant clones isolated contain visna viral DNA inserts which range in size from 3.1 kb to 9.2 kb. All the clones contain the 5' region intact, but most had sustained deletions of varying lengths in the 3' terminal region of the cloned fragment.     

Biotechnology applied to mining of metals

The present review describes the advances achieved during the last two years in the application of biotechnological principles in the extraction of metals from ores and minerals. Despite the fact that this branch of science is very young and many details are yet to be understood, the microbes are applied at commercial levels especially for the extraction of copper and uranium from low-grade ores. The technique is far from being developed to its full potential and it is generally recognized to be a technology of the future. The studies involved are complex and multidisciplinary in nature.     

四川省自贡市幼儿园3至5岁儿童乙型肝炎病毒感染情况及影响因素

为了解四川省自贡地区3～5岁幼儿乙型肝炎病毒(HBV)感染情况,并探索与感染有关的因素,1985年调查了1167名幼儿,其HBV总感染率为41.13％,HBsAg阳性率12.68％。幼儿的HBV感染与母亲HBsAg阳性密切相关。共检查母亲409例,38例HBsAg阳性,其幼儿HBsAg阳性率为50％(19/38),HBsAg阴性的母亲371例,其幼儿HBsAg阳性率9.97％(37/371),来自HBsAg阳性母亲的阳性子女占33.3％(19/56)。1986年随访HBV易感幼儿448例,HBV年感染率为12.95％(58/448),HBsAg年阳转率3.79％。HBV年感染率与原幼儿班级HBsAg阳性率的高低有关。     

不同胃疾患胃内微生态变化的研究

本文对75例不同胃疾患胃液内的菌群及影响胃内微生态环境的因素进行了研究,发现健康胃内基本无菌或只有少量口腔细菌,未发现厌氧菌。而不同胃疾患胃内均分离到细菌(log10~n/ml),慢性萎缩性胃炎:3.89±0.99,残胃炎:4.45±0.16,胃癌:4.23,十二指肠球部溃疡治疗前(2.8±0.62)与抗酸治疗后(4.35±0.61)差别显著,慢性浅表性胃炎:3.39±0.98,胃溃疡:3.42±0.29。所分离到的细菌既有来自于口腔的细菌,也有来自于肠道的细菌。影响胃内细菌增殖的主要因素是胃液的PH值,幽门功能失调及幽门切除亦可使胃内细菌过度生长。本研究提示对胃病的治疗亦应进行生态防治。