Influence of oxygen transfer rate on vinegar production by Acetobacter aceti in submerged fermentation

Summary A study was carried out on the influence of oxygen transfer rate on bacterial growth and acid production in submerged vinegar fermentation by an industrial culture of Acetobacter aceti. The production rate grew as did growth rate even if no increment in cellular mass was noticed when oxygen transfer rate was increased. The relationship between growth and production followed a mixed growth associated model.     

The origin of telocentric chromosomes in man: A girl with tel(Xq)

Summary A mentally retarded girl with several Turner symptoms had the chromosome constitution 46,X,tel(Xq). The abnormal X chromosome appeared to be completely telocentric and stable. It was late-replicating and formed a smaller than normal Barr body. The origin of telocentric chromosomes is discussed.     

Human telomeric 6; 19 translocation chromosome with a tendency to break at the fusion point

The behavior of a translocation chromosome t(6; 19) in the lymphocytes of a mentally retarded woman with other anomalies has been analyzed. The two chromosomes were attached at the telomeres of their short arms without any apparent deletion. The centromere of chromosome 19 was marked by a primary constriction and the site of the centromere of chromosome 6 by a C-band, but no constriction. The translocation chromosome showed two primary constrictions once in 8,800 metaphases, probably resulting from mitotic crossing-over. One or both chromatids of the translocation chromosome were broken at the attachment point with a frequency of 1/733 cells. In addition, the chromosome was often bent at this point and the translocated chromosomes 19 and 6 showed a differential spiralization. In this characteristic as well as the weakness of the fusion point, this chromosome differed from other translocations; the fusion obviously was not as firm as in translocations in general. The broken-off chromosome 6 did not regain a primary constriction, but had the appearance of a large acentric fragment. The segregation of the translocation chromosome and the fragment gave rise to a complicated mosaicism with various levels of ploidy for the fragment lacking a functional centromere. The data are in quantitative agreement with the equilibrium expectations under the assumption that each fragment goes to either pole at random in mitosis and that cells divide at the same rate regardless of ploidy. The high rate of nondisjunction of the fragment showed that the inactivated centromere of the translocation chromosome did not regain its activity when chromosome 19 with the functional centromere became separated from it. — The fragility and the behavior of the translocation chromosome and the production of telomeric associations are briefly discussed.     

Redistribution of rat renal allograft-responding leukocytes during rejection: 1. Model

We describe a model that enables us to trace the traffic of allograft-responding inflammatory leukocytes to and from the graft without handling of these cells in vitro. At different times after transplantation, the kidney transplant pedicle—including the artery, vein, and draining lymphatics—is clamped. The allograft-responding leukocytes are labeled by a [³H]thymidine pulse either in situ or in the systemic lymphoid organs of the recipient. Fifteen minutes later the pulse is chased with a 1000-fold excess of cold thymidine, and the clamp is opened. The animals are sacrificed 18 hr later, when a balance between the synthesis of new labeled leukocytes from the originally labeled ones and dilution of intracellular label has been achieved. This model was used to analyze the allograft-responding inflammatory cell traffic to and from a renal transplant performed across the major histocompatibility complex in the rat. A sizable traffic was observed to both directions: After systemic injection of label only 0.008 × 10⁶ labeled cells × hr^?1 were found to emigrate into a kidney allograft (control). Already on the third day after transplantation—when the in situ inflammatory response is still at its beginning—more than 0.3 × 10⁶ labeled cells × hr^?1 migrated from the host to the allograft and 1.6 × 10⁶ labeled cells × hr^?1 left the allograft to the recipient spleen. The first figure is several-fold higher than any previous estimate. The findings emphasize the systemic nature of the antiallograft inflammatory response.     

An increased frequency of chromosomal changes and SCE's in cultured blood lymphocytes of 12 subjects vaccinated against smallpox

Summary An increased frequency of chromosomal changes and sister chromatid exchanges was detected in 10 women 7 days after smallpox vaccination.     

Climate change can alter competitive relationships between resident and migratory birds

Climate change could affect resource competition between resident and migratory bird species by changing the interval between their onsets of breeding or by altering their population densities. We studied interspecific nest-hole competition between resident great tits and migrant pied flycatchers in South-Western Finland over the past five decades (1953-2005). We found that appearance of fatal take-over trials, the cases where a pied flycatcher tried to take over a great tit nest but was killed by the tit, increased with a reduced interspecific laying date interval and with increasing densities of both tits and flycatchers. The probability of pied flycatchers taking over great tit nests increased with the density of pied flycatchers. Laying dates of the great tit and pied flycatcher are affected by the temperatures of different time periods, and divergent changes in these temperatures could consequently modify their competitive interactions. Densities are a result of reproductive success and survival, which can be affected by separate climatic factors in the resident great tit and trans-Saharan migrant pied flycatcher. On these bases we conclude that climate change has a great potential to alter the competitive balance between these two species.     

Regulation of ezrin localization by Rac1 and PIPK in human epithelial cells

Regulation of ezrin and other ERM proteins is not completely understood, but the involvement of Rho GTPases seems crucial. In this work, expression plasmids encoding full-length, deleted or truncated ezrin were constructed and coexpressed with Rac1 GTPase in HeLa human epithelial cells in order to elucidate the mechanisms of ezrin activation and function. We observed induction of actin stress fiber formation by ezrin constructs harboring the F-actin binding site but devoid of sequences required for intra- or intermolecular binding. Stress fiber-inducing ezrin mutants were localized in adherens junctions containing N-cadherin but no E-cadherin, and also colocalized with F-actin in stress fibers. This localization required the activity of Rac1 and phosphatidylinositol-4-phosphate 5-kinase and involved RhoA. We suggest that localization of ezrin in adherens junctions is regulated by Rac in a manner involving PIPK.     

Warming impacts on boreal fen CO2 exchange under wet and dry conditions

Northern peatlands form a major soil carbon (C) stock. With climate change, peatland C mineralization is expected to increase, which in turn would accelerate climate change. A particularity of peatlands is the importance of soil aeration, which regulates peatland functioning and likely modulates the responses to warming climate. Our aim is to assess the impacts of warming on a southern boreal and a sub‐arctic sedge fen carbon dioxide (CO₂) exchange under two plausible water table regimes: wet and moderately dry. We focused this study on minerotrophic treeless sedge fens, as they are common peatland types at boreal and (sub)arctic areas, which are expected to face the highest rates of climate warming. In addition, fens are expected to respond to environmental changes faster than the nutrient poor bogs. Our study confirmed that CO₂ exchange is more strongly affected by drying than warming. Experimental water level draw‐down (WLD) significantly increased gross photosynthesis and ecosystem respiration. Warming alone had insignificant impacts on the CO₂ exchange components, but when combined with WLD it further increased ecosystem respiration. In the southern fen, CO₂ uptake decreased due to WLD, which was amplified by warming, while at northern fen it remained stable. As a conclusion, our results suggest that a very small difference in the WLD may be decisive, whether the C sink of a fen decreases, or whether the system is able to adapt within its regime and maintain its functions. Moreover, the water table has a role in determining how much the increased temperature impacts the CO₂ exchange.     

Air pollution fades the plumage of the Great Tit

1. Great Tits ( Parus major ) derive the carotenoid pigments for their yellow plumage via the prey items in their diet. Air pollution is known to affect the abundance of many forest insects, e.g. green caterpillars, which are an important source of food and pigments for tits. This study investigates whether air pollutants indirectly affected the intensity of the yellow colour in P. major plumage via the reduced access to carotenoid sources.
2. The intensity of the yellow colour in the plumage of P. major nestlings was scored and the relative abundance of green herbivorous larvae in territories around a polluting copper smelter in SW Finland was simultaneously measured.
3. Both the intensity of yellow colour in nestling plumage and caterpillar abundance increased with increasing distance from the pollution source. The colour intensity correlated significantly with the density of green herbivorous larvae in a territory.
4. Parus major nestlings were significantly heavier at distant sites than close to the pollution source which suggests that the future survival probability of pale nestlings may be lowered.
5. Young birds, after their first moult, were studied for the relationships between condition, size and plumage colour by the means of ptilochronology. The plumage colour intensity did not correlate with the size corrected width of the growth bars in fifth rectrix (condition at moult) but was correlated positively with the length of the rectrix (size).
6. The implications of colour change for survival and mate choice are discussed.