Life history tradeoffs in relation to the degree of polyandry and developmental pathway in Pieris napi (Lepidoptera, Pieridae)

Pieris napi females have different heritable reproductive tactics. Polyandrous females have higher lifetime fecundity, whereas monandrous ones start to reproduce at a faster rate. Butterfly larvae are time‐constrained in seasonal environments. Thus, polyandry is expected to be associated with fast juvenile development, which may result in biased mortality due to physiological costs. We compared how females with varying degrees of polyandry allocate between duration of larval period and achievable size in directly developing and over‐wintering generations. Offspring survival and growth were monitored under a high density and low quality diet. Polyandrous females developed at a faster rate than monandrous ones, regardless of developmental pathway. The growth rate of female offspring correlated with their mothers’ degree of polyandry, which underpins polyandry and monandry as distinct strategies with life history differences reaching beyond mating frequency. The high growth rate of polyandrous females resulted in a short larval period among directly developing females, and in large size within an over‐wintering cohort. A change in either the duration of the larval period or pupal mass had no significant effect on the other, emphasising that growth rate is not necessarily a simple outcome of the tradeoff between development time and size at maturity. The correlation between the degree of polyandry and juvenile growth rate diminished when larvae were exposed to environmental stress, which offers an explanation why juvenile mortality was decoupled from mating tactic. We conclude that polyandry is a strategy that allows larvae to utilise optimal conditions in a more effective way than monandry. As a consequence, polyandrous females either achieve larger size or they mature faster. This gives them a double advantage over monandrous ones within an over‐wintering generation or diminishes the effects of asynchronous hatching of offspring within a directly developing generation. Possible costs of high growth rate are discussed.     

High frequency one-step gene replacement in Trichoderma reesei. I. Endoglucanase I overproduction

The chromosomal cellobiohydrolase 1 locus (cbh1) of the biotechnologically important filamentous fungus Trichoderma reesei was replaced in a single-step procedure by an expression cassette containing an endoglucanase I cDNA (egl1) under control of the cbh1 promoter. CBHI protein was missing from 37–63% of the transformants, showing that targeting of the linear expression cassette to the cbh1 locus was efficient. Studies of expression of the intact cbh1-egl1 cassette at the cbh1 locus revealed that egl1 cDNA is expressed from the cbh1 promoter as efficiently as cbh1 itself. Furthermore, a strain carrying two copies of the cbh1-egl1 expression cassette produced twice as much EG I as the amount of CBHI, the major cellulase protein, produced by the host strain. The level of egl1-specific mRNA in the single-copy transformant was about 10-fold higher than that found in the non transformed host strain, indicating that the cbh1 promoter is about 10 times stronger than the egl1 promoter. The 10-fold increase in the secreted EG I protein, measured with an enzyme-linked immunosorbent assay (ELISA), correlated well with the increase in egl1-specific mRNA.     

A Genetic Polymorphism in Coumarin 7-Hydroxylation: Sequence of the Human CYP2A Gnes and Identification of Variant CYP2A6 Alleles

A group of human cytochrome P450 genes encompassing the CYP2A, CYP2B, and CYP2F subfamilies were cloned and assembled into a 350-kb contig localized on the long arm of chromosome 19. Three complete CYP2A genes—CYP2A6, CYP2A7, and CYP2A13—plus two pseudogenes truncated after exon 5, were identified and sequenced. A variant CYP2A6 allele that differed from the corresponding CYP2A6 and CYP2A7 cDNAs previously sequenced was found and was designated CYP2A6ν2. Sequence differences in the CYP2A6ν2 gene are restricted to regions encompassing exons 3, 6, and 8, which bear sequence relatedness with the corresponding exons of the CYP2A7 gene, located downstream and centromeric of CYP2A6ν2, suggesting recent gene-conversion events. The sequencing of all the CYP2A genes allowed the design of a PCR diagnostic test for the normal CYP2A6 allele, the CYP2A6ν2 allele, and a variant—designated CYP2A6ν1—that encodes an enzyme with a single inactivating amino acid change. These variant alleles were found in individuals who were deficient in their ability to metabolize the CYP2A6 probe drug coumarin. The allelic frequencies of CYP2A6ν1 and CYP2A6ν2 differed significantly between Caucasian, Asian, and African-American populations. These studies establish the existence of a new cytochrome P450 genetic polymorphism.     

Chlorophyll-Protein Complexes in Salix sp. 'Aquatica Gigantea' under Strong and Weak Light I. Spectral Characterization of the Chlorophyll-Protein Complexes

The distribution of chlorophyll in the chlorophyll-protein complexeswas studied in Salix sp. ‘aquatica gigantea’ grownunder high and low irradiance. The chlorophyll- containing bandsthat could be separated by SDS-polyacrylamide gel electrophoresisin strong and weak light numbered 9 to 13 and 9 to 11, respectively.In strong light the following bands were separated, in the orderof the highest to the lowest molecular weight: one to two chlorophylla/b-protein complexes, three to four chlorophyll a-containingbands similar to the P700-chlorophyll a-protein complex (CPIand its oligomers), three oligomers of the light-harvestingchlorophyll a/b-protein complex (LHCP^***, LHCP^**, LHCP^*), twochlorophyll a-protein complexes (CPa₂ and CPa₁), the light-harvestingchlorophyll a/b-protein complex (LHCP) and the protein freepigment (FP). In weak light the same chlorophyll-containingbands were separated with the exception that no high molecularweight chlorophyll a/b-protein complexes could be observed.In strong light the CPI complexes were the largest structuralcomponent of the chloroplast lamellae. In weak light the LHCPcomplexes together contributed the major proportion of the totalchlorophyll. The increase in the chlorophyll associated withthe LHCP complex was possibly caused by reorganization of thelamellar structure or by increased synthesis of the LHCP^** complex,which appeared to be a labile complex in weak light. (Received February 1, 1982; Accepted May 10, 1982)     

Mitochondrial DNA variation of Salvelinus species found in Finland

Mitochondrial DNA (mtDNA) was purified from the Arctic charr, Salvelinus alpinus , the brook charr, Salvelinus fontinalis , and the lake charr, Salvelinus namaycush , and digested with restriction enzymes Ava II, Hinf I, Eco R V, Pst I and Xba I. Two Arctic charr samples were from natural populations and they represented two different morphotypes of Arctic charr. All other studied populations were hatchery maintained. Eight additional restriction enzymes and double digestions were employed to study morphotypes of Arctic charr. We distinguished two morphotypes with restriction enzyme Nci I. Sequence divergence among mtDNA types was 2.9–3.8% between S. alpinus and S. fontinalis , 3.4–4.6% between S. alpinus and S. namaycush , and 4.7–5.3% between S. fontinalis and S. namaycush . lntraspecific variation was lowest in Arctic charr, the average of nucleon diversity for three populations being 0.179, while for brook charr and for lake charr nucleon diversity was 0.334 and 0.550, respectively. According to the number of mtDNA types, it is obvious that introduction to Finland and hatchery propagation have not greatly affected the mtDNA variation of brook charr or lake charr.     

Circadian Phase in Adults of Contrasting Ages

There is evidence that aging may impair phase‐shifting responses to light synchronizers, which could lead to disturbed or malsynchronized circadian rhythms. To explore this hypothesis, 62 elder participants (age, 58 to 84 years) and 25 young adults (age, 19 to 40 years) were studied, first with baseline 1‐wk wrist actigraphy at home and then by 72 h in‐laboratory study using an ultra‐short sleep‐wake cycle. Subjects were awake for 60 minutes in 50 lux followed by 30 minutes of darkness for sleep. Saliva samples were collected for melatonin, and urine samples were collected for aMT6s (a urinary metabolite of melatonin) and free cortisol every 90 minutes. Oral temperatures were also measured every 90 minutes. The timing of the circadian rhythms was not significantly more variable among the elders. The times of lights‐out and wake‐up at home and urinary free cortisol occurred earlier among elders, but the acrophases (cosinor analysis‐derived peak time) of the circadian rhythm of salivary melatonin, urinary aMT6s, and oral temperature were not significantly phase‐advanced among elders. The estimated duration of melatonin secretion was 9.9 h among elders and 8.4 h among young adults (p<0.025), though the estimated half‐life of blood melatonin was shorter among elders (p<0.025), and young adults had higher saliva melatonin and urinary aMT6s levels. In summary, there was no evidence for circadian desynchronization associated with aging, but there was evidence of some rearrangement of the internal phase‐angles among the studied circadian rhythms.     

Sexual selection for bright females prevails under light pollution

The functions of sexually selected traits are particularly sensitive to changes in the environment because the traits have evolved to in-crease mating success u...     

A prevalent POLG CAG microsatellite length allele in humans and African great apes

The human nuclear gene for the catalytic subunit of mitochondrial DNA polymerase (POLG) contains within its coding region a CAG microsatellite encoding a polyglutamine repeat. Previous studies demonstrated an association between length variation at this repeat and male infertility, suggesting a mechanism whereby the prevalent (CAG)₁₀ allele, which occurs at a frequency of >80% in different populations, could be maintained by selection. Sequence analysis of the POLG CAG microsatellite region of more than 1000 human chromosomes reveals that virtually all allelic variation at the locus is accounted for by length variation of the CAG repeat. Analysis of POLG from African great apes shows that a prevalent length allele is present in each species, although its exact length is species-specific. In common chimpanzee (Pan troglodytes) a number of different sequence variants contribute to the prevalent length allele, strongly supporting the idea that the length of the POLG microsatellite region, rather than its exact nucleotide or amino acid sequence, is what is maintained. Analysis of POLG in other primates indicates that the repeat has expanded from a shorter, glutamine-rich sequence, present in the common ancestor of Old and New World monkeys.     

A novel automated fluorometric assay to evaluate sperm viability and fertility in dairy bulls

The artificial insemination (AI) industry is in need of an objective and rapid, but inexpensive method to evaluate frozen thawed bull semen ejaculates. This study presents a new fluorescence method that uses an automatized fluorometer and fluorophore stain propidium iodide that stains only those cells with damaged membranes. The fluorescence of the semen sample and the totally killed subsample were measured simultaneously, and viability was calculated. Every semen batch was analyzed before use in AI. For fertility evaluation, the nonreturn rates (NR%) obtained from 92,120 inseminations with the analyzed batches were recorded from 166 bulls (436 batches). This study confirms a 3.9% better NR% for the Finnish Holstein-Friesian breed than for Finnish Ayrshire. There was a clear seasonality in NR%: it differed (5.3%) significantly, being best in summer to autumn (June to October) and lowest in winter (January to March). The fluorometer method was fast and easy. The correlation between the total number of viable spermatozoa in an insemination dose and field fertility was low but significant (r = 0.051, P = 0.016), suggesting that the plasma membrane integrity evaluation can serve as a cost-beneficial quality control method of frozen-thawed semen at bull stations.