Female mate choice,male migration,and the threat of infanticide in ringtailed lemurs

Summary Paternity determination by DNA fingerprinting is reported for a long-term study group of semi-free-ranging ringtailed lemurs (Lemur catta), together with behavioral data collected independently. In 1985, fraternal twin males unfamiliar and unrelated to the resident ringtailed lemurs were introduced to the forest enclosure. Every mature resident male attacked the immigrants frequently across the next 5 months, whereas no female ever did. All observed estrous females showed sexual proceptivity toward the' immigrant males; three solicited copulation exclusively from them. Each female repelled sons, matrilineal brothers, and other resident males from attempting to copulate. Over a 5-year period, four of five females always reproduced with distantly related or unrelated males (Fig. 3). Despite low dominance status throughout the case study, an immigrant sired the off-spring of each female that was proceptive toward only the immigrants, demonstrating that female choice can override male dominance relations to determine reproductive success among male ringtailed lemurs. In the birth season following the 1985–1986 immigration, each of four females targeted one or two particular adult males for consistent attack across the period of infant dependency, beginning days after parturition. Paternity determinations, colony records, and subsequent study of two groups allowed 66 cases of this mode of maternal aggression to be documented. In each, the targeted male had not fathered the protected infant, and almost invariably, he was unrelated to the infant's mother. New mothers attacked every male that immigrated following their infants' conceptions and a few familiar males with whom they had not been seen to copulate during the previous breeding season. Recent attempts by immigrant males to kill infants confirmed the anti-infanticidal function of maternal targeting of males. All results were interpreted together to advance a prospective model of the mating system of ringtailed lemurs. Female avoidance of incest has led to the evolution of natal male dispersal. Subsequently, males should prefer to transfer into groups containing few and/or status-vulnerable males. We predict that, by killing others' infants, males simultaneously increase chances for success in females' next reproductive efforts and terminate current fathers' reproductive eligibility in a group. Basic hypotheses that await testing are that (a) raising an infant through weaning reduces a female's chances for reproductive success the following year and (b) males that demonstrate the capacity to promote the survival of infant offspring are most attractive to females as mates.     

Episodic targeting aggression and the histories of Lemur social groups

Summary Periodically, members of captive Lemur social groups target others for intense aggression. Over periods of several days, weeks, and sometimes months, one to three lemurs persistently follow and attack one or two particular group mates until the targets no longer associate with their group. Episodic targeting aggression is nonrandom with regard to time of year, group size and sex ratio, and the kinship, age, and gender of targets. The vast majority of episodes observed over the past 18 years at the Duke University Primate Center (DUPC) has occurred between like-sex adolescents and adults in conjunction with estrous cycling or infant births and most often after groups have reached apparent critical sizes. When unrelated adults have shared group membership, members of one family have almost invariably first targeted members of the other. In several groups, entire matrilines have gradually been evicted by members of another across periods of several years. When non-relatives have been absent, lemurs have evicted relatives that had previously formed separate subgroups. Episodic targeting aggression has been documented at the DUPC in over a dozen different social groups, comprising three different species. The phenomenon occurs repeatedly in groups held in a variety of large outdoor runs as well as in outdoor enclosures providing naturalistic space and physical structure. More-over, an appreciable number of recent observations in Madagascar suggest that the patterns we have documented well represent the phenomenon as it occurs in the wild. Targeting aggression based on group size, sex ratio, kinship and gender has been reported for no other primate taxon. We suggest that episodic targeting aggression reflects heretofore undescribed tactics in reproductive competition that may characterize many lemurid and indriid taxa. As such, the phenomenon has broad implications for the structure of lemur social groups and populations. Provisional models of the social dynamics and histories of Lemur social groups are presented for evaluation during upcoming field work.     

Environmentally friendly bleaching of cotton using laccases

A new strain of Trametes hirsuta was found to oxidize various cotton flavonoids. Here we show that laccases of this organism were responsible for oxidation of the flavonoids morin, luteolin, rutin and quercetin. Out of two laccases produced by T. hirsuta (60.7 and 51.0 kDa) the more prominent 60.7 kDa laccase was purified and showed K _m and k _cat values of 75.5, 20.9 and 49.4 μM and 72.5, 96.3 and 32.7 s⁻¹, hours on ABTS, syringaldazide and DMP, respectively. Pretreatment of cotton with the T. hirsuta laccase resulted in a whiteness increase of 8.5%.     

Sorption of pentachlorophenol on pine bark

The minimization of pentachlorophenol (PCP) transport in the environment driven by industrial wastewater discharges can be accomplished by sorption in natural, available and low cost by-products like pine bark. Taking into account that PCP is a chemical which behaviour is highly dominated by the surrounding features, this work intended to evaluate the sorption kinetics and equilibrium parameters according to the pH and temperature as well as the pine bark particle size. The PCP uptake by pine bark showed to be faster in the initial phase followed by a slower process, being 24 h the suitably time to reach the sorption equilibrium in the range of pH studied. The neutral PCP species showed to have higher binding capacity to pine bark than the anionic PCP, which was reflected in a decrease in the distribution coefficient (Kd) of the linear sorption isotherm with the increase of solution pH from 2 to 7. On the other hand, between 10 degrees C and 35 degrees C, the temperature does not seem to play a significant role in the PCP sorption by pine bark, while the sorbent size is a key parameter to enhance the overall process.     

Euglena gracilis as a model for the study of Cu and Zn toxicity and accumulation in eukaryotic cells

We have observed the effect of copper and zinc on the biology of Euglena gracilis. The cells displayed different sensitivities to these metals, as the apparent LC₅₀ for Cu²⁺ was 0.22 mM, and for Zn²⁺ it was 0.88 mM. While Zn²⁺ was able to increase cell proliferation even at 0.1 mM, the minimal CuCl₂ concentration tested (0.02 mM) was sufficient to impair cell division. Higher concentrations of these metals not only inhibited cell division in a concentration-dependent manner, but also interfered with the metabolism of E. gracilis. A higher accumulation of proteins and lipids per cell was observed at the DI₅₀ concentration for metal-treated cells. These results suggest that the test concentration of both metals leads to a failure in completing cell division. Ultrastructural analysis indicated a chloroplast disorganization in copper-treated cells, as well as the presence of electron dense granules with different shapes and sizes inside vacuoles. Microanalysis of these granules indicated an accumulation of copper, thus suggesting a detoxification role played by the vacuoles. These results indicate that E. gracilis is an efficient biological model for the study of metal poisoning in eukaryotic cells. They also indicate that copper and zinc (copper being more poisonous) had an overall toxic effect on E. gracilis and that part of the effect can be ascribed to defects in the structure of chloroplast membranes.     

Acute and chronic impacts caused by aromatic hydrocarbons on bacterial communities at Boa Viagem and Forte do Rio Branco Beaches, Guanabara Bay, Brazil

The bacterial community presented significantly different hydrocarbonoclastic activity under acute and chronic impacts. Benzoic acid, toluene, benzene and xylene were used in final concentrations of 5, 10 and 15 mM and bacterial biomass was quantified through protein dosage. Under acute impact, the highest biomass percentages occurred between the 11th and 14th days; under chronic impact, between the 20th and 29th days. Under acute and chronic impacts, the bacterial biomass presented higher nutritional specialization at Boa Viagem Beach, using the aromatic hydrocarbons up to a concentration of 15 mM. Under acute impact, the concentration of the hydrocarbons constituted a critical factor for the bacterial flora from Forte do Rio Beach, because biomass increases only occurred in concentrations of 5 mM; under chronic impact, the aromatic hydrocarbons induced the specialization and increased bacterial biomass for 15 mM toluene. Benzoic acid (15 mM) was used by the bacteria from Boa Viagem and Forte do Rio Branco Beaches.     

Influence of air pollution on the incidence of respiratory tract neoplasm

To evaluate the possible influence of air pollutants on the incidence of respiratory tract neoplasm we studied 12 S?o Paulo City districts where air pollution is observed. We collected data on pollutants from 1981-1990 and correlated it with the incidence of larynx and lung neoplasms in 1997. Ozone was the pollutant that best correlated with the incidence of neoplasm. The correlation coefficients were 0.7234 (p=0.277) and 0.9929 (p=0.007) for lung and larynx cancer, respectively. There may be a relationship between air pollution and the incidence of respiratory tract neoplasm. This study, however, does not allow us to conclude that there is a causal relationship.     

Sustainable watershed management: an international multi-watershed case study

Global freshwater resources are being increasingly polluted and depleted, threatening sustainable development and human and ecosystem health. Utilizing case studies from 4 different watersheds in the United States, Japan, Switzerland, and Brazil, this paper identifies the most relevant sustainability deficits and derives general vectors for more sustainable water management. As a consequence of the demographic and economic developments experienced in the last few decades, each watershed has suffered declines in water quality, streamflow and biotic resources. However, the extent and the cultural perception of these water-related problems vary substantially in the different watersheds, leading to specific water-management strategies. In industrialized countries, exemplified by the US, Switzerland, and Japan, these strategies have primarily consisted of finance- and energy-intensive technologies, allowing these countries to meet water requirements while minimizing human health risks. But, from a sustainability point of view, such strategies, relying on limited natural resources, are not long-term solutions. For newly industrialized countries such as Brazil, expensive technologies for water management are often not economically feasible, thus limiting the extent to which newly industrialized and developing countries can utilize the expertise offered by the industrialized world. Sustainable water management has to be achieved by a common learning process involving industrialized, newly industrialized, and developing countries, following general sustainability guidelines as exemplified in this paper.     

Radon in indoor air of primary schools: determinant factors,their variability and effective dose

Radon is a radioactive gas, abundant in granitic areas, such as in the city of Porto at the north-east of Portugal. This gas is a recognized carcinogenic agent, being appointed by the World Health Organization as the leading cause of lung cancer after smoking. The aim of this preliminary survey was to determine indoor radon concentrations in public primary schools, to analyse the main factors influencing their indoor concentration levels and to estimate the effective dose in students and teachers in primary schools. Radon concentrations were measured in 45 classrooms from 13 public primary schools located in Porto, using CR-39 passive radon detectors for about 2-month period. In all schools, radon concentrations ranged from 56 to 889 Bq/m³ (mean = 197 Bq/m³). The results showed that the limit of 100 Bq/m³ established by WHO IAQ guidelines was exceeded in 92 % of the measurements, as well as 8 % of the measurements exceeded the limit of 400 Bq/m³ established by the national legislation. Moreover, the mean annual effective dose was calculated as 1.25 mSv/y (ranging between 0.58 and 3.07 mSv/y), which is below the action level (3–10 mSv). The considerable variability of radon concentration observed between and within floors indicates a need to monitor concentrations in several rooms for each floor. A single radon detector for each room can be used, provided that the measurement error is considerably lower than variability of radon concentration between rooms. The results of the present survey will provide useful baseline data for adopting safety measures and dealing effectively with radiation emergencies. In particular, radon remediation techniques should be used in buildings located in the highest radon risk areas of Portugal. The results obtained in the current study concerning radon levels and their variations will be useful to optimize the design of future research surveys.