Macromolecular crowding and the mandatory condensation of DNA in bacteria

Cellular DNA in bacteria is localized into nucleoids enclosed by cytoplasm. The forces which cause condensation of the DNA into nucleoids are poorly understood. We suggest that direct and indirect macromolecular crowding forces from the surrounding cytoplasm are critical factors for nucleoid condensation, and that within a bacterial cell these crowding forces are always present at such high levels that the DNA is maintained in a condensed state. The DNA affected includes not only the preexisting genomic DNA but also DNA that is newly introduced by viral infection, replication or other means.     

Macromolecular composition of the sarcolemma and endomysium in the rat

The macromolecular composition of sarcolemma and endomysium was studied by classical staining methods for glycosaminoglycans and using immunological techniques for proteins. Both proteoglycans and glycosaminoglycans (heparan sulphate, dermatan sulphate, chondroitin sulphate) could be detected in the sarcolemma. Type IV and type V collagen and laminin were found exclusively in the sarcolemma and endomysium. Type I and type III collagen as well as fibronectin were detected both in the endomysium and perimysium.     

Phospholipid composition of methane-utilizing bacteria.

The phospholipids of Methylococcus capsulatus, Methylosinus trichosporium, La Paz, and OBT were examined in relation to their qualitative and quantitative composition. M. capsulatus exhibited a phospholipid composition consisting of phosphatidylethanolamine, phosphatidylglycerol, cardiolipin, and phosphatidyl-choline. The esterified fatty acids were predominantly C16:0 and C16:1. M. trichosporium, La Paz, and OBT exhibited an essentially identical phospholipid composition consisting of phosphatidylmonomethylethanolamine, phosphatidyl-dimethylethanolamine, phosphatidylcholine, and phosphatidylglycerol. Only trace amounts (less than 1%) of cardiolipin were found in these organisms. The major esterified fatty acid in these organisms was C18:1 (87 to 90%). The monounsaturated fatty acids from all four organisms consisted of both cis and trans isomers, each of which contained delta8, delta9, delta10, and delta11 double-bond positional isomers.     

Macromolecular composition of Palaeozoic scolecodonts: insights into the molecular taphonomy of zoomorphs

Dutta, S., Hartkopf‐Fröder, C., Mann, U., Wilkes, H., Brocke, R. & Bertram, N. 2010: Macromolecular composition of Palaeozoic scolecodonts: insights into the molecular taphonomy of zoomorphs. Lethaia, Vol. 43, pp. 334–343. Biogeochemistry and molecular taphonomy of biopolymers of marine zoomorphs are poorly known. In order to obtain insights into this issue we report on the biogeomacromolecular composition of hand‐picked, well‐preserved scolecodonts of Ordovician, Silurian and Devonian age using micro‐Fourier transform infrared (micro‐FTIR) spectroscopy, Curie point pyrolysis‐gas chromatography‐mass spectrometry (Cupy‐GC‐MS) and tetramethylammonium hydroxide (TMAH)‐assisted thermochemolysis‐GC‐MS. The present study reveals that scolecodonts are composed of both aliphatic and aromatic moieties. The micro‐FTIR spectra of scolecodonts are characterized by aliphatic CH_x (3000–2800 and 1460–1450/cm) and CH₃ (1375/cm) absorptions and aromatic C=C (1560–1610/cm) and CH (3050/cm and 700–900/cm) absorptions. The major pyrolysis products from the scolecodonts include aromatic hydrocarbons such as alkylbenzenes, alkylnaphthalenes and alkylphenols. Aliphatic hydrocarbons are represented by a homologous series of n‐alkenes and n‐alkanes. The compounds released upon thermochemolysis with TMAH are saturated and unsaturated fatty acids (as their methyl esters), n‐alkenes/alkanes and aromatic acids (as their methyl esters). No protein/amino acid‐derived compounds have been recognized in the pyrolysates or in the thermochemolysates, and it is concluded that protein/amino acid‐related compounds, which are commonly found in the jaws of extant polychaetes, were destroyed due to diagenetic processes. Obviously, excellent morphological preservation and low thermal alteration are not paralleled by a similar degree of chemical preservation. □Biogeomacromolecules, micro‐FTIR, pyrolysis‐GC‐MS, scolecodonts, thermochemolysis‐GC‐MS.     

Elemental composition of extremely alkaliphilic anaerobic bacteria

The contents of several chemical elements were assessed in the haloalkaliphilic acetogenic bacterium Natroniella acetigena and the alkaliphilic sulfate-reducing bacterium Desulfonatronum lacustre using X-ray microanalysis, stereoscanning microscopy, and mass spectrometry. The organisms were found to differ significantly in their relative contents of S, K, P, and Cl. The P/S ratio in cells of the alkaliphilic bacteria studied grown on mineral media at different pH was pH-dependent. With a pH increase from 9 to 10, potassium extrusion from cells was observed, suggesting that secondary K+/H+ antiport activity accounts for the homeostasis of cytosolic pH. Deenergization of bacterial cells in the presence of inhibitors and ionophores results in specific changes in the P/S ratio, which may be considered an indicator of the cell energetic state. In Natroniella acetigena, the content of intracellular Cl was directly proportional to the NaCl concentration in the medium. Some metals were shown to be necessary for the N. acetigena viability; the requirement for Ni and Co was absolute. Although little demand for Mg was characteristic of the bacteria studied, their growth was stimulated by an increase in Mg concentration, and the cell resistance to lysis was enhanced.     

Fatty acid composition of various hyphal budding bacteria

The total fatty acid composition of various strains of Hyphomicrobium, Pedomicrobium, and Rhodomicrobium spp. was determined by gas chromatography. In addition, the fatty acid pattern of a new hyphal budding bacterium, strain F-1, was compared with the other patterns obtained. Octadecenoic acid was the main component in most strains, comprising up to 75% of the total fatty acids. Lactobacillic acid and 3-methoxy-tetradecanoic acid were present in varying amounts in the lipids of all organisms except for the new isolate, F-1. This latter strain contained, however, large amounts of iso-heptadecanoic and iso-heptadecenoic acids, not present in the other budding bacteria studied. This composition was consistently found under various culture conditions. The data indicate that, except for the new bacterium F-1, the hyphal budding bacteria studied here are closely related. The total fatty acid composition is thought to be a useful taxonomic criterion for differentiation of these bacteria.     

Macromolecular relationships of liver nuclei and amino acid composition of total histones during bovine ontogeny

The weight of the liver and the macromolecular composition of the liver and its nuclei during bovine ontogeny were compared. The findings suggest that bovine liver growth proceeds in three phases. The macromolecular composition of the liver nuclei was found to remain fairly constant throughout bovine ontogeny.     

Macromolecular composition of phloem exudate from white lupin (Lupinus albus L.)

Background  

Members of the legume genus Lupinus exude phloem 'spontaneously' from incisions made to the vasculature. This feature was exploited to document macromolecules present in exudate of white lupin (Lupinus albus [L.] cv Kiev mutant), in particular to identify proteins and RNA molecules, including microRNA (miRNA).