ALBERT

Notes: Abstract  Regenerating forests have become a common land-cover type throughout the Brazilian Amazon. However, the potential for these systems to accumulate and store C and nutrients, and the fluxes resulting from them when they are cut, burned, and converted back to croplands and pastures have not been well quantified. In this study, we quantified pre- and post-fire pools of biomass, C, and nutrients, as well as the emissions of those elements, at a series of second- and third-growth forests located in the states of Pará and Rondônia, Brazil. Total aboveground biomass (TAGB) of second- and third-growth forests averaged 134 and 91 Mg ha–1, respectively. Rates of aboveground biomass accumulation were rapid in these systems, but were not significantly different between second- and third-growth forests, ranging from 9 to 16 Mg ha–1 year–1. Residual pools of biomass originating from primary forest vegetation accounted for large portions of TAGB in both forest types and were primarily responsible for TAGB differences between the two forest types. In second-growth forests this pool (82 Mg ha–1) represented 58% of TAGB, and in third-growth forests (40 Mg ha–1) it represented 40% of TAGB. Amounts of TAGB consumed by burning of second- and third-growth forests averaged 70 and 53 Mg ha–1, respectively. Aboveground pre-fire pools in second- and third-growth forests averaged 67 and 45 Mg C ha–1, 821 and 707 kg N ha–1, 441 and 341 kg P ha–1, and 46 and 27 kg Ca ha–1, respectively. While pre-fire pools of C, N, S and K were not significantly different between second- and third-growth forests, pools of both P and Ca were significantly higher in second-growth forests. This suggests that increasing land use has a negative impact on these elemental pools. Site losses of elements resulting from slashing and burning these sites were highly variable: losses of C ranged from 20 to 47 Mg ha–1; N losses ranged from 306 to 709 kg ha–1; Ca losses ranged from 10 to 145 kg ha–1; and P losses ranged from 2 to 20 kg ha–1. Elemental losses were controlled to a large extent by the relative distribution of elemental mass within biomass components of varying susceptibilities to combustion and the temperatures of volatilization of each element. Due to a relatively low temperature of volatilization and its concentration in highly combustible biomass pools, site losses of N averaged 70% of total pre-fire pools. In contrast, site losses of P and Ca resulting from burning were 33 and 20% of total pre-fire pools, respectively, as much of the mass of those elements was deposited on site as ash. Pre- and post-fire biomass and elemental pools of second- and third-growth forests, as well as the emissions from those systems, were intermediate between those of primary forests and pastures in the Brazilian Amazon. Overall, regenerating forests have the capacity to act as either large terrestrial sinks or sources of C and nutrients, depending on the course of land-use patterns within the Brazilian Amazon. Combining remote sensing techniques with field measures of aboveground C accumulation in regenerating forests and C fluxes from those forests when they are cut and burned, we estimate that during 1990–1991 roughly 104 Tg of C was accumulated by regenerating forests across the Brazilian Amazon. Further, we estimate that approximately 103 Tg of C was lost via the cutting and burning of regenerating forests across the Brazilian Amazon during this same period. Since average C accumulations (5.5 Mg ha–1 year–1) in regenerating forests were 19% of the C lost when such forests are cut and burned (29.3 Mg ha–1), our results suggest that when less than 19% of the total area accounted for by secondary forests is cut and burned in a given year, those forests will be net accumulators of C during that year. Conversely, when more than 19% of regenerating forests are burned, those forests will be a net source of C to the atmosphere.

Notes: Abstract  Numerous hypotheses have been proposed for the commonly observed, positive relationship between local abundance and geographic distribution in groups of closely related species. Here I consider how hostplant specialization and abundance affect the relative abundance and distribution of lycaenid butterflies (Lepidoptera: Lycaenidae). I first discuss three components of specialization: local specialization, turnover of specialization across a species’ range, and the minimum number of resources (or habitats) required by a species. Within this framework, I then consider one dimension of a lycaenid species’ niche, larval hostplant specialization. In a subalpine region of Colorado, I surveyed 11 lycaenid species and their hostplants at 17 sites. I compare this local information to continental hostplant use and large-scale distributions of the lycaenids and their hostplants. Local abundance of a lycaenid species is positively correlated with its local distribution (the number of sites occupied), but not with its regional or continental distribution. Neither local specialization (the number of hostplants used within one habitat) nor continental specialization (the number of hostplants used across many habitats) is correlated with local lycaenid abundance. Continental specialization is positively correlated with a species’ continental distribution, however. Finally, while generalist butterflies tend to have more hostplant available to them, differences in resource availability do not explain the differences in butterfly abundance. Although local abundance is correlated only with local distribution, I suggest that abundance-distribution relationships might emerge at regional and continental scales if local abundance were averaged across many habitat types. Consideration of the scale of a species’ resource specialization (within or among habitats) appears to be key to understanding the relationships between resource specialization, resource availability, and a species’ abundance and distribution.

Notes: Abstract. The collagen type Iα1 Sp1 (ColIA1) polymorphism has been associated with reduced bone mineral density (BMD) and increased prevalence of osteoporosis. This study examines associations of the ColIA1 genotype with BMD and 5-year rates of change in BMD in elderly men and women. The 243 subjects, aged 65 years and older, were participants in two consecutive studies lasting a total of 5-years. BMD of the total body, femoral neck, and lumbar spine were made by dual-energy X-ray absorptiometry (DXA). The distribution of the genotypes (155 in the SS genotype, 79 in Ss, and 9 in ss) was proportionately similar to those reported by others. Baseline BMD did not differ significantly at any skeletal site. Unadjusted 5-year percent changes in BMD differed significantly by genotype only at the total body (P= 0.009), where the change was −0.29 ± 0.21 (SEM) in the SS genotype, −0.60 ± 0.25 in the Ss genotype, and −3.01 ± 0.72 in the ss genotype. This 9.4% increase in bone loss of the ss genotype relative to the SS genotype was reduced to an 8.9% increase after adjustment for sex, age, weight, and supplementation group. Results at the femoral neck were directionally similar, but not statistically significant. No effect of genotype on change in spine BMD was observed. In conclusion, bone loss from the total body was significantly greater in elderly men and women who were homozygous for the s allele compared with heterozygotes and SS homozygotes. This finding suggests a possible explanation for the association of the ColIA1 polymorphism with increased rates of osteoporotic fracture, but should be interpreted with caution because of the small number of subjects in the unfavorable ss genotype.

Notes: Abstract. Men and women (n = 518) receiving moderate-to-high doses of corticosteroids were enrolled in two studies with similar protocols and randomly assigned to receive either placebo or risedronate (2.5 or 5 mg) for 1 year. All patients received daily calcium supplementation (500–1000 mg), and most also received supplemental vitamin D (400 IU). The primary endpoint was the difference between the placebo and active groups in lumbar spine bone mineral density (BMD) at 1 year; changes in BMD at other sites, biochemical markers of bone turnover, and the incidence of vertebral fractures were also assessed. In the overall population, the mean (SE) lumbar spine BMD increased 1.9 ± 0.38% from baseline in the risedronate 5 mg group (P 〈 0.001) and decreased 1.0 ± 0.4% in the placebo group (P= 0.005). BMD at the femoral neck, trochanter, and distal radius increased or was maintained with risedronate 5 mg treatment, but decreased in the placebo group. Midshaft radius BMD did not change significantly in either treatment group. The difference in BMD between the risedronate 5 mg and placebo groups was significant at all skeletal sites (P 〈 0.05) except the midshaft radius at 1 year. The 2.5 mg dose also had a positive effect on BMD, although of a lesser magnitude than that seen with risedronate 5 mg. A significant reduction of 70% in vertebral fracture risk was observed in the risedronate 5 mg group compared with the placebo group (P= 0.01). Risedronate was efficacious in both men and women, irrespective of underlying disease and duration of corticosteroid therapy, and had a favorable safety profile, with a similar incidence of upper gastrointestinal adverse events in the placebo and active treatment groups. Daily treatment with risedronate 5 mg significantly increases BMD and decreases vertebral fracture risk in patients receiving moderate-to-high doses of corticosteroid therapy.

Notes: Abstract A high total pneumocandin titer (B0 + C0) with a low percentage of the structural isomer pneumocandin C0 was achieved by carrying out fermentations of Glarea lozoyensis at a high residual fructose concentration (125 g/l initial). When the fermentation was carried out at a low residual fructose concentration (40 g/l initial), pneumocandin production increased by 34%. However, a disproportionate increase in the level of pneumocandin C0 synthesized (250% increase vs 30% increase for pneumocandin B0) was observed. Midcycle addition of 150 mM NaCl or 116 mM Na2SO4 to low residual fructose fermentations returned the titer and isomer levels to those seen for the high residual fructose fermentation. The increase in pneumocandin C0 synthesis under low residual fructose conditions appears to be linked to the increase in the synthesis of trans-4 hydroxyproline, with the synthesis of trans-3 hydroxyproline remaining unaffected. This suggests that the formation of pneumocandin C0 is the result of a misincorporation of trans-4 hydroxyproline instead of trans-3 hydroxyproline by the pneumocandin peptide synthetase, and that the amount of trans-4 hydroxyproline formed dictates the frequency of this misincorporation.

Notes: Summary 1. The chromosomes of the African scale, Aspidoproctus maximus Louns., number 5 in the male, 6 in the female; sex chromosomes are of the XO male, XX female type. 2. Male meiosis is similar to that found in the Neotropical Llaveiini, with vesiculation of prophase nuclei, broadly dispersed polar centers, and divergent chromosomal fibers. The usual sequence of co-orientation and auto-orientation in meiosis is inverted; the chromosomes are autooriented at Metaphase I, and co-oriented at Metaphase II. 3. Asynapsis of one pair of autosomes occurs in from 14% to 52% (in different individuals) of the primary spermatocytes. Regular segregation of asynaptic chromosomes is ensured by a secondary pairing during interkinesis. 4. In spermiogenesis the chromosomes, linearly aligned, move out of the nucleus into the tail filament which forms a non-flagellated sperm.

Notes: Summary A wide diversity in chromosome complement is found in two species of phasmids of the primitive group Prisopini—Prisopus ariadne Hebard and Prisopus berosus Westwood. P. ariadne has a diploid male complement of 28, comprising 13 pairs of relatively large mediokinetic autosomes and Neo XY sex chromosomes. P. berosus, 2n ♂=49, has relatively small autosomes most of which are mediokinetic, and retains the XO—XX sex mechanism. Chromosomal polymorphism in this species is suggested by the presence of an unequal pair of autosomes and a structural differentiation in the X in one of two males studied. The relative amount of DNA per nucleus in male germ cells (Peulgen cytophotometry) shows a significant difference in total chromosomal content between the complements of the two species. These data are discussed with reference to the cytotaxonomy of phasmids.

Notes: Summary 1. Male germ cells ofPseudaulacaspis pentagona (TARG.), an exceptional species of the coccid subfamilyDiaspinae, contain only approximately half as much DNA (measured by Feulgen cytophotometry) as do those ofChrysomphalus ficus Ash. — a typical representative of the group. 2. Reversing this relationship, the chromosomes ofP. pentagona number 16 in the female, 8 in the male — whileC. ficus has the basic complement of the subfamily, numbering 8 in the female, 4 in the male (Brown andBentsnett 1957). 3. The total mass of the chromosomes in the 2 complements is roughly proportional to the DNA values. It is concluded that 2 downward shifts in the level of chromosomal polyteny have been associated with the doubling of the chromosome number inPseudaulacaspis pentagona. 4. The cytology of the diaspines is discussed in relation to the evolutionary origin of male haploidy in coccids.

Notes: Summary 1. The tropical species of the genus Thyanta conform, in their chromosome formula (2n♂=12+XY, 2n♀=12+2X), to that which is typical for the Family of Pentatomidae (Hemiptera), while the more northern species examined by us have either added a pair of chromosomes (T. custator and T. pallidovirens) or have doubled the basic number (T. calceata). 2. Hybrids between T. custator and T. pallidovirens show only minor disturbances in their meiosis, and the hybrid spermatids carry the same number of chromosomes and amount of DNA as are present in the spermatids of either parent species. 3. The meiosis of the hybrid between T. calceata and T. pallidovirens is quite abnormal and there is no chromosome pairing. Nevertheless, chromosome segregation is not completely at random and some functional sperms are formed. 4. The nuclei of the six species of Thyanta tested show little difference in their DNA contents. On the other hand, the nuclei of another pentatomid, Arvelius, contain at least twice as much DNA. 5. In considering the evolutionary origin of such a high chromosome number as that of T. calceata, the evidence adduced in the present investigation more or less precludes the involvement of polyploidy. Instead, some type of fragmentation was probably responsible for the doubled number. 6. It is difficult to conceive of such fragmentation as occurring transversely through the chromosomes. We propose a consideration of “longitudinal fragmentation” or better, a separation of the chromatids of each chromosome and the establishment of “echromatid autonomy”. 7. Except where polyploidy is involved, great differences in the nuclear contents of DNA, as observed between some Classes and Orders, must in certain cases be due to different degrees of polyteny and not to the addition of new or different genes. Our evidence demonstrates that relatively large differences of DNA may also exist in systematic groups of a lower category, such as the Genera of the same Tribe, or perhaps even the Species of the same Genus. On this basis, the degree of polyteny may differ even in closely related forms.