Damages Caused by Irradiation in the Presence of NaCl in Macromolecular Components of E. coli

Damages in macromolecular components and in their functions of E. coli produced by gamma irradiation in the presence of higher concentration of NaCl were determined with reference to the basic mechanism for NaCl radiosensitization. As the results, inhibitions of DNA repair, of DNA degradation, of macromolecular syntheses and of RNA species formation were found in DNA repair proficient strains. The number of radiation-induced DNA-strand breaks was not increased by the presence of 1 m NaCl during irradiation. It was suggested that inhibition of DNA repair may be of primary importance among these lesions for NaCl radiosensitization.     

High‐resolution prediction of leaf onset date in Japan in the 21st century under the IPCC A1B scenario

Reports indicate that leaf onset (leaf flush) of deciduous trees in cool‐temperate ecosystems is occurring earlier in the spring in response to global warming. In this study, we created two types of phenology models, one driven only by warmth (spring warming [SW] model) and another driven by both warmth and winter chilling (parallel chill [PC] model), to predict such phenomena in the Japanese Islands at high spatial resolution (500 m). We calibrated these models using leaf onset dates derived from satellite data (Terra/MODIS) and in situ temperature data derived from a dense network of ground stations Automated Meteorological Data Acquisition System. We ran the model using future climate predictions created by the Japanese Meteorological Agency's MRI‐AGCM3.1S model. In comparison to the first decade of the 2000s, our results predict that the date of leaf onset in the 2030s will advance by an average of 12 days under the SW model and 7 days under the PC model throughout the study area. The date of onset in the 2090s will advance by 26 days under the SW model and by 15 days under the PC model. The greatest impact will occur on Hokkaido (the northernmost island) and in the central mountains.     

Multispectral image analysis for algal biomass quantification

This article reports a novel multispectral image processing technique for rapid, noninvasive quantification of biomass concentration in attached and suspended algae cultures. Monitoring the biomass concentration is critical for efficient production of biofuel feedstocks, food supplements, and bioactive chemicals. Particularly, noninvasive and rapid detection techniques can significantly aid in providing delay‐free process control feedback in large‐scale cultivation platforms. In this technique, three‐band spectral images of Anabaena variabilis cultures were acquired and separated into their red, green, and blue components. A correlation between the magnitude of the green component and the areal biomass concentration was generated. The correlation predicted the biomass concentrations of independently prepared attached and suspended cultures with errors of 7 and 15%, respectively, and the effect of varying lighting conditions and background color were investigated. This method can provide necessary feedback for dilution and harvesting strategies to maximize photosynthetic conversion efficiency in large‐scale operation. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:808–816, 2013     

Pseudomonas fluorescens,a potential bacterial antagonist to control plant diseases

Abstract

Fluorescent Pseudomonads belong to plant Growth Promoting Rhizobacteria (PGPR), the important group of bacteria that play a major role in the plant growth promotion, induced systemic resistance, biological control of pathogens etc. Many strains of Pseudomonas fluorescens are known to enhance plant growth promotion and reduce severity of various diseases. The efficacy of bacterial antagonists in controlling fungal diseases was often better as alone, and sometimes in combination with fungicides. The present review refers to occurrence, distribution, mechanism, growth requirements of P. fluorescens and diseases controlled by the bacterial antagonist in different agricultural and horticultural crops were discussed. The literature in this review helps in future research programmes that aim to promote P. fluorescens as a potential bio-pesticide for augmentative biological control of many diseases of agriculture and horticultural importance.     

Effect of methionine and its related compounds on rumen bacterial activity

The effect of several methionine sources (L‐methionine = L‐MET; DL‐ methionine = DL‐MET, DL‐S‐methyl‐methionine‐sulphonium‐chloride = SMM; N‐hydroxymethyl‐DL‐methionine‐Ca = NHM; methionine‐hydroxy‐analog free acid=MHA; methionine‐sulphoxyde=MSO) on rumen bacterial growth was studied using a new methodical approach which utilises a methionine free assay medium (Bacto Methionine Assay Media, Difco) supplemented by increasing quantities of the methionine sources and inoculated with one drop of diluted rumen bacteria. The optical density was measured after 18 h incubation on 39 °C.

L‐ and DL‐MET promoted the highest growth response, while SMM and NHM exerted significantly (p < 0.05) lower optical densities. MHA and MSO showed no growth response.

The methodical approach and the possible bacterial strains, which might have contributed to the growth response have been discussed.     

Buchbesprechungen

Abstract

Schenk/Kolb: Grundriß der physiologischen Chemie, 6. überarbeitete Auflage. Erschienen im VEB Gustav Fischer Verlag Jena, 1971. Mit 116 Abb. und 237 Tab., Ganzleinen, Format 10,5 × 24,5 cm. Preis: 30,—M. Reviewed by H. Bergner.

H. Bergner: Energie — Leben — Leistung — Nahrung. Erschienen im Urania-Verlag Leipzig-Jena-Berlin 1971, 144 Seiten, mit 49 Abb. und 25 Tab., Ganzleinen, Format 14,5 × 21,5 cm, Preis: 9,80 M. Reviewed by H. Haenel.

G. Dirksen, W. Kaufmann und E. Pfeffer: Untersuchungen zur Verdauungs physiologie der Milchkuh mit der Umleitungstechnik am Duodenum. Erschienen im Verlag Paul Parey, Hamburg und Berlin 1972. 43 Seiten mit 10 Abb. und 22 Tab., kart., Format 16,5 × 25 cm, Preis: 22,00 DM (als Beiheft zur Z. Tierphys. Tierernähr. Futtermittelkd., für Bezicher der Zeitschrift 20,35 DM). Reviewed by H. Bergner.     

Bacterial colonization of Hydra hatchlings follows a robust temporal pattern

Animals are colonized by complex bacterial communities. The processes controlling community membership and influencing the establishment of the microbial ecosystem during development are poorly understood. Here we aimed to explore the assembly of bacterial communities in Hydra with the broader goal of elucidating the general rules that determine the temporal progression of bacterial colonization of animal epithelia. We profiled the microbial communities in polyps at various time points after hatching in four replicates. The composition and temporal patterns of the bacterial communities were strikingly similar in all replicates. Distinct features included high diversity of community profiles in the first week, a remarkable but transient adult-like profile 2 weeks after hatching, followed by progressive emergence of a stable adult-like pattern characterized by low species diversity and the preponderance of the Betaproteobacterium Curvibacter. Intriguingly, this process displayed important parallels to the assembly of human fecal communities after birth. In addition, a mathematical modeling approach was used to uncover the organizational principles of this colonization process, suggesting that both, local environmental or host-derived factor(s) modulating the colonization rate, as well as frequency-dependent interactions of individual bacterial community members are important aspects in the emergence of a stable bacterial community at the end of development.     

Drosophila melanogaster brain invasion: pathogenic Wolbachia in central nervous system of the fly

The pathogenic Wolbachia strain wMelPop rapidly over‐replicates in the brain, muscles, and retina of Drosophila melanogaster, causing severe tissue degeneration and premature death of the host. The unique features of this endosymbiont make it an excellent tool to be used for biological control of insects, pests, and vectors of human diseases. To follow the dynamics of bacterial morphology and titer in the nerve cells we used transmission electron microscopy of 3‐d‐old female brains. The neurons and glial cells from central brain of the fly had different Wolbachia titers ranging from single bacteria to large accumulations, tearing cell apart and invading extracellular space. The neuropile regions of the brain were free of wMelPop. Wolbachia tightly interacted with host cell organelles and underwent several morphological changes in nerve cells. Based on different morphological types of bacteria described we propose for the first time a scheme of wMelPop dynamics within the somatic tissue of the host.     

Functional diversity of potassium channel voltage-sensing domains

Voltage-gated potassium channels or Kv's are membrane proteins with fundamental physiological roles. They are composed of 2 main functional protein domains, the pore domain, which regulates ion permeation, and the voltage-sensing domain, which is in charge of sensing voltage and undergoing a conformational change that is later transduced into pore opening. The voltage-sensing domain or VSD is a highly conserved structural motif found in all voltage-gated ion channels and can also exist as an independent feature, giving rise to voltage sensitive enzymes and also sustaining proton fluxes in proton-permeable channels. In spite of the structural conservation of VSDs in potassium channels, there are several differences in the details of VSD function found across variants of Kvs. These differences are mainly reflected in variations in the electrostatic energy needed to open different potassium channels. In turn, the differences in detailed VSD functioning among voltage-gated potassium channels might have physiological consequences that have not been explored and which might reflect evolutionary adaptations to the different roles played by Kv channels in cell physiology.