Detection of genetic variants affecting cattle behaviour and their impact on milk production: a genome‐wide association study

Behaviour traits of cattle have been reported to affect important production traits, such as meat quality and milk performance as well as reproduction and health. Genetic predisposition is, together with environmental stimuli, undoubtedly involved in the development of behaviour phenotypes. Underlying molecular mechanisms affecting behaviour in general and behaviour and productions traits in particular still have to be studied in detail. Therefore, we performed a genome‐wide association study in an F₂ Charolais × German Holstein cross‐breed population to identify genetic variants that affect behaviour‐related traits assessed in an open‐field and novel‐object test and analysed their putative impact on milk performance. Of 37 201 tested single nucleotide polymorphism (SNPs), four showed a genome‐wide and 37 a chromosome‐wide significant association with behaviour traits assessed in both tests. Nine of the SNPs that were associated with behaviour traits likewise showed a nominal significant association with milk performance traits. On chromosomes 14 and 29, six SNPs were identified to be associated with exploratory behaviour and inactivity during the novel‐object test as well as with milk yield traits. Least squares means for behaviour and milk performance traits for these SNPs revealed that genotypes associated with higher inactivity and less exploratory behaviour promote higher milk yields. Whether these results are due to molecular mechanisms simultaneously affecting behaviour and milk performance or due to a behaviour predisposition, which causes indirect effects on milk performance by influencing individual reactivity, needs further investigation.     

Sulfide induces phosphate release from polyphosphate in cultures of a marine Beggiatoa strain

Sulfur bacteria such as Beggiatoa or Thiomargarita have a particularly high capacity for storage because of their large size. In addition to sulfur and nitrate, these bacteria also store phosphorus in the form of polyphosphate. Thiomargarita namibiensis has been shown to release phosphate from internally stored polyphosphate in pulses creating steep peaks of phosphate in the sediment and thereby inducing the precipitation of phosphorus-rich minerals. Large sulfur bacteria populate sediments at the sites of recent phosphorite formation and are found as fossils in ancient phosphorite deposits. Therefore, it can be assumed that this physiology contributes to the removal of bioavailable phosphorus from the marine system and thus is important for the global phosphorus cycle. We investigated under defined laboratory conditions which parameters stimulate the decomposition of polyphosphate and the release of phosphate in a marine Beggiatoa strain. Initially, we tested phosphate release in response to anoxia and high concentrations of acetate, because acetate is described as the relevant stimulus for phosphate release in activated sludge. To our surprise, the Beggiatoa strain did not release phosphate in response to this treatment. Instead, we could clearly show that increasing sulfide concentrations and anoxia resulted in a decomposition of polyphosphate. This physiological reaction is a yet unknown mode of bacterial polyphosphate usage and provides a new explanation for high phosphate concentrations in sulfidic marine sediments.     

Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria

We present evidence for a dimorphic life cycle in the vacuolate sulfide-oxidizing bacteria that appears to involve the attachment of a spherical Thiomargarita-like cell to the exteriors of invertebrate integuments and other benthic substrates at methane seeps. The attached cell elongates to produce a stalk-like form before budding off spherical daughter cells resembling free-living Thiomargarita that are abundant in surrounding sulfidic seep sediments. The relationship between the attached parent cell and free-living daughter cell is reminiscent of the dimorphic life modes of the prosthecate Alphaproteobacteria, but on a grand scale, with individual elongate cells reaching nearly a millimeter in length. Abundant growth of attached Thiomargarita-like bacteria on the integuments of gastropods and other seep fauna provides not only a novel ecological niche for these giant bacteria, but also for animals that may benefit from epibiont colonization.     

The semidian rhythm in flowering response of Pharbitis nil in relation to dark period time measurement and to a circadian rhythm

When seedlings of Pharbitis nil Choisy, cv. Violet, are exposed to a single inductive dark period at 27°C, brief interruptions with red light (R) can be promotive after 2–3 h of darkness but increasingly inhibitory to flowering up to the 8–9th h of darkness. This rhythmic response to R interruptions can be advanced in phase by > 1 h when the preceding light period is interrupted with far-red (FR) 2 h before darkness (FR -2 h) or with FR – 15 h, whereas FR –8 h or FR–22 h retard the rhythm. These shifts in the R interruption rhythm are paralleled by equal shifts in the length of the dark period required for flowering. Brief FR interruptions of darkness displayed a similar rhythm which was also advanced by FR –2 h and retarded by FR –8 h. We conclude therefore that the semidian rhythm in the light, which we have previously described, continues through at least the first 12 h of darkness, is manifested in the R interruption rhythm, and determines the critical night length. A circadian rhythm with a marked effect on flowering was also identified, but several lines of evidence suggest that the circadian and semidian rhythms have independent additive effects on flowering and do not appear to show phase interaction.     

Two Agrobacterium tumefaciens genes for cytokinin biosynthesis: Ti plasmid-coded isopentenyltransferases adapted for function in prokaryotic or eukaryotic cells

Summary Tzs and ipt are two Ti plasmid genes coding for proteins with isopentenyltransferase (IPT) activity in vitro. We cloned both genes for protein expression in Escherichia coli and in Agrobacterium tumefaciens, and we investigated differences between the two genes by analysing the properties of the proteins in vitro and in vivo. In vitro, extracts with tzs or ipt-coded proteins had high IPT activity, and the enzymes were identical in most properties. The most important difference was detected in vivo: the tzs-encoded protein was very active in cytokinin production, while the ipt protein required overexpression in order to obtain measurable activity in bacteria. In both cases, rans-zeatin was the major product of the gene activity. Formation of this cytokinin requires a hydroxylase function in addition to the IPT reaction. No such activity could be ascribed to tzs or ipt-encoded proteins in vitro or in vivo, but cytokinin hydroxylase activity was detected in cells and extracts of E. coli, regardless of the presence or absence of the cytokinin genes. Based on these results it is proposed that both genes code for a single enzyme activity (isopentenyltransferase), that the genes and proteins are adapted for function either in bacteria (tzs) or in transformed plant cells (ipt), and that in both prokaryotic and eukaryotic cells hydroxylation to trans-zeatin is a function contributed by host enzymes.Abbreviations DMAPP dimethylallylpyrophosphate - iP isopentenyladenine - iPA isopentenyladenosine - iPMP isopentenyladenosine 5-monophosphate - IPT isopentenyltransferase - trans-Z trans-zeatin     

Fate of salmonellas and competing flora in meat sample enrichments in buffered peptone water and in Muller-Kauffmann's tetrathionate medium

Studies have been carried out in which growth patterns of a Salmonella sp. and competing micro-organisms, especially other Enterobacteriaceae, were followed during pre-enrichment in buffered peptone water (BPw) and subsequent selective enrichment in tetrathionate broth (TBB). Pre-enrichment cultures were inoculated with minced meat and three reference samples containing nalidixic acid-resistant salmonellas. Irrespective of their initial numbers in BPw, Enterobacteriaceae increased to 10(8)/ml or more. During incubation in TBB at 43 degrees C, numbers of lactose-positive Enterobacteriaceae decreased in most enrichments which resulted in a positive salmonella isolation, but remained constant in the majority of those that did not. Levels of lactose-negative Enterobacteriaceae did not decrease in most salmonella-positive tests, but did so in half of the salmonella-negative ones. In the salmonella-positive tests the numbers of salmonellas had increased to 10(3)-10(7)/ml in BPw and after transfer to TBB slowly reached 10(4)/ml or more. In all cases the numbers of salmonellas exceeded those of the competing flora on brilliant green agar (BGA). In the salmonella-negative tests the numbers of salmonellas had increased less in BPw and decreased in most of the TBB enrichments. In none of these negative tests did the numbers of salmonellas exceed those of the competing flora on BGA. Escherichia coli dominated in most of the salmonella-negative tests. The results suggest more influence of lactose-positive than lactose-negative Enterobacteriaceae on the detection of salmonellas. The effect of competing microorganisms seems to depend not only upon their initial numbers, but also upon the types that can interact with salmonellas during selective enrichment.     

Single-strand conformation polymorphism (SSCP) analysis of exon 11 of the CFTR gene reliably detects more than one third of non-ΔF508 mutations in German cystic fibrosis patients

Summary In Central Europe, the F508 deletion accounts for approximately 75% of mutations in the cystic fibrosis transmembrane conductance regulator gene causing cystic fibrosis. The remainder comprise a large number of individually infrequent mutations whose detection requires a disproportionately large effort. However, a sizeable proportion of non-F508 mutations have been found to cluster within exon 11. We have taken advantage of this clustering to detect a total of five previously described point mutations present on 26/72 (36%) non-F508 chromosomes by polymerase chain reaction/direct sequencing of exon 11. These exon 11 mutations were then subjected to single-strand conformation polymorphism (SSCP) analysis, which was shown (i) to discriminate reliably between mutant and wildtype alleles and (ii) to generate reproducible mutation-specific band patterns. This analysis thus represents the first attempt to assess SSCP analysis retrospectively, and serves to illustrate the potential of this screening technique in diagnostic medicine.     

Specific photoperiodic stimulation of dry matter production in a high-latitude cultivar of Poa pratensis

Vegetative plants of Poa pratensis L. cv. Holt (origin 69°N) raised in short days gave large and significant increases in plant dry weight, plant height and leaf area upon exposure to continuous light, compared with 8-h short days, at essentially identical daily inputs of radiant energy (8-h summer daylight ± low intensity extension). For example, by the fourth harvest (after 26, 34 and 46 days at 21, 15 and 9°C, respectively), the dry weights of plants in long days were 81, 163 and 195% greater than those of the corresponding short-day controls at the respective temperatures. Plant leaf areas in long days were between two and four times as large as control values by the end of the experiment. This was mainly due to increased leaf length caused by long-day stimulation of cell extension and division. However, the photoperiod did not affect the partitioning of assimilates amongst leaves, culms and stolons. Most of these effects could also be brought about by exogenous gibberellin application to plants in short days. However, in contrast to the effect of long days, gibberellin treatment also induced stem internode elongation even in these vegetative plants. Examination by standard growth analysis procedures revealed that the observed increases in relative growth rate were due primarily to increased net assimilation rate followed, several days later, by increases in leaf area ratio when newly-emerged leaves began to constitute a significant proportion of the leaf area. It is concluded that these reactions are of great adaptive significance for growth at the marginal temperatures prevailing at high latitudes.     

Interaction of Growth Retardants and Temperature in Growth, Flowering, Regeneration, and Auxin Activity of Begonia × cheimantha Everett

Soil application of CCC reduced stem and leaf growth in Begonia plants. This effect was evident with all concentrations tested at 18°C, whereas at 21 and 24°C no growth–retarding effect was observed with 2 × 10^?2 M CCC, and with 5 × 10^?3 M growth was even stimulated. Flowering was promoted by CCC in long day and neur–critical temperature, particularly under low light intensity in the winter. The formation of adventitious buds in leaves of plants grown at 21 and 24°C was stimulated when the plants received 5 × 10^?2 and 2 × 10^?2 M CCC, while 8 7times; 10^?2 M was inhibitory. In plants grown at 18°C bud formation was inhibited by all CCC concentrations. Root formation in the the leaves was usually stimulated by high CCC concentrations, while root elongation was reduced. The level of ether–extractable. acidic auxin (presumably IAA) in the leaves was lowered by CCC treatment of the plants, hut this required higher CCC concentrations at higt than at low temperature. When applied to detached leaves CCC stimulated bud formation at concentrations ranging from 10^?4 to 10^?2 M in leaves planted at 18 and 21°C. At 24°C budding was inhibited by 10^?2 M CCC, the lower concentrations being stimulatory also at this temperature. Root formation and growth were not much affected by CCC treatment of the leaves, but increased with the temperature. Soil application of Phosfon (4 × 10^?4 M) had no effect on growth and flowering, nov did it affect the subsequent regeneration of buds and roots in the leaves. In detached leaves Phosfon stimulated bud formation with au optimum at 10^?6 M. Root formation was stimulated by Phosfon at all temperatures, the optimal concentration being 10^?5 M, whereas root length was conversely affected. Foliar application of B-995 to intact plants and treatment of detached leaves greatly inhibited the formation of buds and had little effect on root formation. B-99D reduced the growth and delayed flowering in the plants.