Small bacteriophages

Acceptability, Appropriateness, and Preliminary Effects of the PrEP Diffusion Training for Lay HIV Workers: Increased PrEP Knowledge, Decreased Stigma, and Diffusion of Innovation

Training lay health workers is a critical intervention strategy to support HIV pre-exposure prophylaxis (PrEP) implementation. However, few evaluations of such trainings have been published. We conducted multi-time-point surveys to evaluate the effect of a training intervention on knowledge, PrEP stigma, and implementation behavior among lay HIV workers in China. Results indicated high acceptability and appropriateness of the training. PrEP knowledge score increased by 65% from pre- to post-training, and remained high one-month post-training. We observed a significant decrease in PrEP stigma and a positive influence on determinants of implementation behaviors. All lay HIV workers surveyed one-month after the training reported having disseminated PrEP information in social networks; 43% reported integrating PrEP education into routine work. The training is an effective strategy to build lay HIV workers' capacity in PrEP implementation. Longer-term post-training follow up would be ideal to further assess actual PrEP uptake and sustained effects on PrEP implementation.

History of modern genetics in Germany

The history of modern genetics in Germany during the 20th century is a story of missed chances. In the USA the genetic revolution opened a fascinating new field for ambitious scientists and created a rapidly growing new industry. Meanwhile Germany stood aside, combating with political and social restrictions. Promising young scientists who wanted to work in the field left Germany for the US, and big companies moved their facilities out of the country. Up until the middle of the 1990s molecular biology in Germany remained a "sleeping beauty" even though many brilliant scientists did their jobs very well. Then a somewhat funny idea changed everything: the German minister for education and science proclaimed the BioRegio contest in order to award the most powerful biotechnology region in Germany concerning academia and especially industry. Since then Germany's biotechnology industry has grown constantly and rapidly due to the foundation of a number of small biotech companies; big companies have returned their interests and their investments to Germany, paralleled by an improvement in academic research because of more funding and better support especially for younger scientists. In respect to biotechnology and molecular biology, Germany is still a developing country, but it has started to move and to take its chances in an exciting global competition.

Characteristics of PRD1, a plasmid-dependent broad host range DNA bacteriophage

Several distinctive properties of PRD1, an icosahedral plasmid-dependent phage, are described. The drug-resistance plasmid-dependent host range of PRD1 extends beyond the P incompatibility group and includes gram-negative bacteria containing plasmids of incompatibility groups N and W. PRD1 phage will infect pseudomonads and Enterobacteriaceae containing either a P or W incompatibility group plasmid. PRD1 adsorbs to the cell wall of R(+) bacteria and thus its infectivity indicates cell wall alterations by these drug-resistance plasmid groups. PRD1 nucleic acid is duplex DNA with an estimated molecular weight of 24 x 10(6). The appearance of PRD1 in electron micrographs is suggestive of lipid content in addition to its buoyant density of 1.348 in CsCl and its sensitivity to chloroform. The latent period of PRD1 varies with the R(+) host bacterial strain used for growth of the phage.

Purification and some properties of bacteriophage ST-1

Bacteriophage ST-1 is shown to be a small, isometric, single-stranded deoxyribonucleic acid (SS-DNA) virus with a diameter of about 260 nm. Standard methods for growth, assay, preparation of high-titer lysates, and purification of the phage are suggested. ST-1 infects K-12 and not C strains of Escherichia coli and requires a divalent cation to adsorb to susceptible bacteria. Adsorption also requires an activation of the particle brought on by incubation at 37 C. The latent and eclipse periods are essentially identical (9 to 11 min) in ST-1 infections, with an average burst size about 250 phages per cell. Multiple densities of ST-1 infectivity are observed during purification in CsCl gradients. The virus recovered from different densities has the same sedimentation coefficient and, therefore, all phage containing fractions are pooled during purification. The purified ST-1 particle has a sedimentation coefficient of 121S relative to phiX-174 (114S) in a sucrose gradient and a molecular weight of 6.8 x 10(6) (as estimated from its relative sedimentation). The nucleic acid is assumed to be SS-DNA on the basis of (i) the specific incorporation of (3)H-thymine, (ii) the dependence of its UV absorption on temperature, and (iii) its reaction with formaldehyde. ST-1 SS-DNA sediments at 24.4S relative to phiX-174 SS-DNA (23.8S).

Pyrimidine sequences from the DNA of bacteriophages fd, fl, and phi X174

By the use of techniques previously developed to determine the sequence of large, unique pyrimidine oligonucleotides in bacteriophage fd DNA, pyrimidine sequences in the related phage fl and the unrelated phage varphiX174 amber 3 were determined. The DNA of fl contains many pyrimidine sequences completely identical to those in fd, including one sequence of 20 base residues. The large pyrimidine oligonucleotides in varphiX174 DNA are quite different from those in fd, although some homology is observed. There is present in each of the phage DNAs a pyrimidine oligonucleotide rich in thymidine that contains a common sequence of C_T_T_T_T_T_T_T.

Mutanten des hüllproteins (b-protein) des bakteriophagen fd

Spontaneous mutants of the bacteriophage fd and mutants resulting from fd-infected cultures of E. coli grown in the presence of 2.7-diaminofluoren and proflavin were isolated by means of free flow electrophoresis.The amino acid analyses of the mutant coat proteins (B-proteins) show significant differences in comparison with the amino acid analyses of wild type coat protein.

Filamentous bacterial viruses

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Physicochemical and biological properties of fibrous Pseudomonas bacteriophages

Two fibrous Pseudomonas phages, Pf1 and Pf2, have been isolated and characterized. The phages were serologically related and were indistinguishable morphologically when viewed by electron microscopy. Both phages formed minute turbid plaques. A simple method was devised for easy differentiation of such plaques from the bacterial lawn. The infected bacteria continued to grow and to liberate the phages into the medium. The phages were collected from the turbid "lysate" by salting out and were purified by differential centrifugation and density gradient centrifugation. The purified phages were sensitive to ultrasonics and to a proteolytic enzyme, Nagarse. A rapid lysis mutant was obtained from the progeny of plaquepurified Pf2. Pf2 was spontaneously produced by strain P28 of P. aeruginosa. Neither acridine orange nor antiserum affected the phage-producing capacity of the bacteria.

Phylogenetic relationships of drug-resistance factors and other transmissible bacterial plasmids

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