Several parameters of phage T4 adsorption to and growth inEscherichia coliB/r were determined. All changed monotonously with the bacterial growth rate (μ), which was modified by nutritional conditions. Adsorption rate was faster at higher μ values, positively correlated to cell size, and increased by pretreatment with low penicillin (Pn) concentrations; it was directly proportional to total cellular surface area, indicating a constant density of T4 receptors on cell envelopes irrespective of growth conditions. Parameters of phage development and cell lysis were μ-dependent. The rate of phage release and burst size increased, while the eclipse and latent periods decreased with increasing μ. Differentiation between the contribution of several physiological parameters to the development of T4 was performed by manipulating the host cells. A competitive inhibitor of glucose uptake, methyl α-D-glucoside, was exploited to reduce the growth rate in the same effective carbon source. Synchronous cells were obtained by the ‘baby-machine’ and large cells were obtained by pretreatment with low Pn concentrations. Lysis was delayed by superinfection, and DNA content and concentration were modified by growing athymutant in limiting thymine concentrations. The results indicate that burst size is not limited by cell size or DNA composition, nor directly by the rate of metabolism, but rather by the rates of synthesis and assembly of phage components and by lysis time. The rates of synthesis and assembly of phage components seem to depend on the content of the protein-synthesizing system and lysis time seems to depend on cellular dimensions.

The entire 127,923-bp sequence of the toxin-encoding plasmid pBtoxis fromBacillus thuringiensissubsp.israelensisis presented and analyzed. In addition to the four known Cry and two known Cyt toxins, a third Cyt-type sequence was found with an additional C-terminal domain previously unseen in such proteins. Many plasmid-encoded genes could be involved in several functions other than toxin production. The most striking of these are several genes potentially affecting host sporulation and germination and a set of genes for the production and export of a peptide antibiotic.

Dust storms include particulate matter that is transported over land and sea with biota that could impact downwind ecosystems. In addition to the physico-chemical compositions, organismal diversities of dust from two storm events in southern Israel, December 2012 (Ev12) and January 2013 (Ev13), were determined by pyro-sequencing using primers universal to 16S and 18S rRNA genes and compared. The bio-assemblages in the collected dust samples were affiliated with scores of different taxa. Distinct patterns of richness and diversity of the two events were influenced by the origins of the air masses: Ev13 was rich with reads affiliated to Betaproteobacteria and Embryophyta, consistent with a European origin. Ev12, originated in north-Africa, contained significantly more of the Actinobacteria and fungi, without conifers. The abundance of bacterial and eukaryotic reads demonstrates dissemination of biological material in dust that may impose health hazards of pathogens and allergens, and influence vegetation migration throughout the world.