Transformation of Saccharomyces cerevisiae with yeast mitochondrial DNA linked to two micron circular yeast plasmid

Mitochondrial DNA from a petite mutant of yeast carrying an oligomycin resistance determinant has been ligated in vitro to 2 μm yeast plasmid DNA. The recombinant DNA so produced has been used to transform an oligomycin sensitive strain of Saccharomyces cerevisiae to oligomycin resistance at a frequency approaching 50 times the spontaneous mutation rate to oligomycin resistance. The majority of transformants showed genetic properties suggesting that recombination between the transforming DNA and the resident mtDNA has occurred. The properties of a subclass of oligomycin resistance transformants suggested that in these cells the transforming DNA has not become stably integrated into the mitochondrial genome of the recipient cell.     

Identification of a soluble protein stimulator of plasmalogen biosynthesis and stearoyl-coenzyme a desaturase

Stimulation of the desaturation of 1-alkyl-2-acyl-sn-glycero-3-phosphoethanolamine (GPE), which forms ethanolamine plasmalogens, by a component of the 105,000g supernatant has been previously reported. We have isolated the stimulatory protein and identified it as catalase. Purified rat liver catalase or commercial bovine liver catalase is as effective in stimulating microsomal 1-alkyl-2-acyl-GPE desaturation as the soluble proteins. The stimulatory effect of these proteins is eliminated by catalase inhibitors. It appears that catalase stimulates the desaturation of 1-alkyl-2-acyl-GPE by preventing inactivation of the enzyme system by H₂O₂ or a decomposition product of H₂O₂. The cytochrome b₅ content and NADH oxidation are depressed in Fischer R-3259 sarcoma microsomes by H₂O₂; this effect is eliminated by catalase. However, since measurable inhibition of 1-alkyl-2-acyl-GPE desaturase by H₂O₂ still occurred in the presence of catalase, the inhibition by H₂O₂ cannot be explained solely on the basis of cytochrome b₅ inactivation. The desaturation of stearoyl-coenzyme A, a reaction analogous in many respects to 1-alkyl-2-acyl-GPE desaturation, was also found to be stimulated by catalase.     

The antagonism by anti-inflammatory analgesics of prostaglandin F2α-induced contractions of human and rabbit myometrium

The anti-inflammatory analgesic drugs, aspirin, indomethacin, phenylbutazone, mefenamic acid, ibuprofen and flurbiprofen are shown to inhibit in a dose-dependent manner the force of contraction of isolated human pregnant myometrial strips which have been stimulated to contract by adding prostaglandin (PG) F_2α to the tissue bath. These drugs and also flufenamic acid and salicin show a similar antagonism of the action of PGF_2α with isolated rabbit non-pregnant myometrium. The ratio of the inhibitory concentration to the maximum plasma level after a normal dose suggests that phenylbutazone and possibly ibuprofen may be capable of inhibiting human uterine contractions . Patients who were treated with aspirin during induction of abortion using PGF_2α during the second trimester of pregnancy showed no significant change in the induction-abortion interval compared with patients not taking aspirin.     

Demographic responses to climate‐driven variation in habitat quality across the annual cycle of a migratory bird species

The demography and dynamics of migratory bird populations depend on patterns of movement and habitat quality across the annual cycle. We leveraged archival GPS‐tagging data, climate data, remote‐sensed vegetation data, and bird‐banding data to better understand the dynamics of black‐headed grosbeak (Pheucticus melanocephalus) populations in two breeding regions, the coast and Central Valley of California (Coastal California) and the Sierra Nevada mountain range (Sierra Nevada), over 28 years (1992–2019). Drought conditions across the annual cycle and rainfall timing on the molting grounds influenced seasonal habitat characteristics, including vegetation greenness and phenology (maturity dates). We developed a novel integrated population model with population state informed by adult capture data, recruitment rates informed by age‐specific capture data and climate covariates, and survival rates informed by adult capture–mark–recapture data and climate covariates. Population size was relatively variable among years for Coastal California, where numbers of recruits and survivors were positively correlated, and years of population increase were largely driven by recruitment. In the Sierra Nevada, population size was more consistent and showed stronger evidence of population regulation (numbers of recruits and survivors negatively correlated). Neither region showed evidence of long‐term population trend. We found only weak support for most climate–demographic rate relationships. However, recruitment rates for the Coastal California region were higher when rainfall was relatively early on the molting grounds and when wintering grounds were relatively cool and wet. We suggest that our approach of integrating movement, climate, and demographic data within a novel modeling framework can provide a useful method for better understanding the dynamics of broadly distributed migratory species.     

The locations of the three cysteine residues in the primary structure of the intrinsic segments of band 3 protein,and implications concerning the arrangement of band 3 protein in the bilayer

The intrinsic domains of band 3 protein contain three cysteine residues, one in a 17 kDa middle segment and two in a 35 kDa C-terminal segment. The latter are retained in an 8 kDa fragment produced by chymotrypsin treatment of ghosts. Cleavage of cysteine residues by 2-nitro-5-thiocyanobenzoic acid (NTCB) allows localization of this amino acid in the primary structure of the 8, 17, 35 and 52 (17 plus 35) kDa segments of band 3 protein. The mapping of these residues taken with other information concerning accessibility of various sites at the two sides of the membrane leads to the conclusion that band 3 protein crosses the membrane at least five times, or ten times in a dimer structure. The implications of this conclusion in terms of band 3 protein structure and function are briefly discussed.     

Simple isolation of functional RNA from woody stems of gymnosperms

Stems of woody conifers contain high levels of polysaccharides and phenolic compounds that complicate the isolation of functional RNA from this highly lignified tissue. These difficulties were overcome by pulverizing the frozen tissue with a stainless-steel mortar and by effectively sequestering interfering phenolic compounds with vinylpyrrolidone polymers, thereby minimizing damage to nucleic acids during extraction. RNases were inhibited by aurintricarboxylic acid, and gelatinous polysaccharides were removed by inclusion of a 10% ethanol precipitation step. RNA was then isolated by precipitation with 33% isopropanol and ultracentrifugation onto a cushion of 5.7 M CsCl. Yields of 10 to 20 μg RNA/g FW were obtained from woody stems of several different gymnosperm species, including grand fir (Abies grandis), lodgepole pine (Pinus contorta), loblolly pine (Pinus taeda), Douglas fir (Pseudotsuga menziesii) and Pacific yew (Taxus brevifolia). The high quality of the RNA obtained was determined by UV-spectrophotometry, denaturing agarose gel electrophoresis, andin-vitro translation, and this material was used to construct cDNA libraries.     

Evaluating the effectiveness of road mitigation measures

The last 20 years have seen a dramatic increase in efforts to mitigate the negative effects of roads and traffic on wildlife, including fencing to prevent wildlife-vehicle collisions and wildlife crossing structures to facilitate landscape connectivity. While not necessarily explicitly articulated, the fundamental drivers behind road mitigation are human safety, animal welfare, and/or wildlife conservation. Concomitant with the increased effort to mitigate has been a focus on evaluating road mitigation. So far, research has mainly focussed on assessing the use of wildlife crossing structures, demonstrating that a broad range of species use them. However, this research has done little to address the question of the effectiveness of crossing structures, because use of a wildlife crossing structure does not necessarily equate to its effectiveness. The paucity of studies directly examining the effectiveness of crossing structures is exacerbated by the fact that such studies are often poorly designed, which limits the level of inference that can be made. Without well performed evaluations of the effectiveness of road mitigation measures, we may endanger the viability of wildlife populations and inefficiently use financial resources by installing structures that are not as effective as we think they are. In this paper we outline the essential elements of a good experimental design for such assessments and prioritize the parameters to be measured. The framework we propose will facilitate collaboration between road agencies and scientists to undertake research programs that fully evaluate effectiveness of road mitigation measures. We discuss the added value of road mitigation evaluations for policy makers and transportation agencies and provide recommendations on how to incorporate such evaluations in road planning practices.     

Kinetics of apparent cell death in yeasts induced by ethanol

Summary Evidence is presented that adaptation of yeast cells to ethanol results in a reduced loss of cell viability induced by exposure to that agent. In line with earlier work, an exponential model is shown to apply when the concentration of ethanol exceeds a critical value, beyond which cell growth cannot occur. Such an exponential model is consistent with the absolute theory of reaction rates. Adaptation of yeast cells to 7% w/v ethanol lowers the specific rate of cell death at various ethanol concentrations by a factor of some 40 fold compared to a non-adapted culture.     

The phosphorylation region of lysine-rich histone in dividing cells

N-Bromosuccinimide cleavage of in vivo ³²P-labelled lysine-rich histone isolated from rapidly dividing cells has been studied. N-Bromosuccinimide cleaves F₁-histone into two fragments, a small N-terminal piece and a larger C-terminal portion. The phosphate-induced microheterogeneity and associated radioactivity which has been linked to cell replication, is found in the carboxyterminal fragment. No phosphorous is found associated with the amino-terminal fragment when histone phosphorylation is associated with cell division. The specific tryptic phosphopeptides obtained from in vivo labelled F₁ are clearly different from those obtained from in vitro incubations of free F₁-histone and cytoplasmic protein kinase.