Are there geniuses among the apes?

We are often asked whether some apes are smarter than others. Here we used two individual-based datasets on cognitive abilities to answer this question and to elucidate the structure of individual differences. We identified some individuals who consistently scored well across multiple tasks, and even one individual who could be classified as exceptional when compared with her conspecifics. However, we found no general intelligence factor. Instead, we detected some clusters of certain abilities, including inferences, learning and perhaps a tool-use and quantities cluster. Thus, apes in general and chimpanzees in particular present a pattern characterized by the existence of some smart animals but no evidence of a general intelligence factor. This conclusion contrasts with previous studies that have found evidence of a g factor in primates. However, those studies have used group-based as opposed to the individual-based data used here, which means that the two sets of analyses are not directly comparable. We advocate an approach based on testing multiple individuals (of multiple species) on multiple tasks that capture cognitive, motivational and temperament factors affecting performance. One of the advantages of this approach is that it may contribute to reconcile the general and domain-specific views on primate intelligence.     

Are there body size implications for the success of globally introduced land birds?

Verbal models have hypothesized a relation between body size and the successful introduction of animal species. This relation is largely based on studies of intrinsic rate of increase in what have been termed "colonizing" species. From these studies it has been predicted that introduction success should be negatively correlated with body size across taxa but positively correlated within closely related taxa. T examine this relation for globally introduced land birds. Introduced land birds are. on average, larger bodied than extant land bird species. Across species, families, and higher family nodes, global introduction success is significantly related to decreasing body size. However, within taxa there is a significant positive relationship between introduction success and body size. I discuss possible explanations for the observed relations and conclude that an indirect but genuine relationship between the introduction success of land birds and their body size is currently the most plausible.     

Special-interest subgroups at the ASCB: Are there multiple roles for the Ran GTPase?

The annual meeting of the American Society for Cell Biology (ASCB) is a large and diverse gathering. At last year's meeting**The American Society for Cell Biology 38th Annual Meeting, San Francisco, USA; 12-16 December, 1998. Program chair: Jennifer Lippincott-Schwartz., there were over 8000 attendees, and the topics discussed covered many areas of cell biology. It would be impossible to cover the entire meeting within a trends in CELL BIOLOGY report, so instead we are focusing on an aspect of it that provided some of the most interesting and fruitful discussions. On Saturday afternoon, before the main symposia began, there were 11 special-interest subgroup meetings. The atmosphere at these meetings was informal, and they encouraged open and frank discussion of data and issues. This report provides a brief summary of the discussions at seven of the special-interest subgroup meetings.     

Are there insertions in the ribosomal DNA of vertebrates?

We have analysed the Eco RI restriction pattern of rDNA of the newt Triturus vulgaris and of some other amphibian species by Southern blotting and hybridization with nick-translated Xenopus rDNA prepared from the recombinant plasmids pXlr11 and pXlr12 (21). After hybridization with r11, the 28S coding fragments become visible in two bands, a prominent one of 5.3 kb and a weak band of 5.9 kb representing about 8% of the 28S genes. The evidence obtained so far by additional digestions with Bam HI and Bgl II indicates that in this species and in Triturus helveticus the coding regions of the 5.9 kb fragments are interrupted by an insertion 0.6 kb in length located in a 1.6 kb Bgl II fragment at the 3' end of the Eco RI fragment, which we believe to be the first described in a vertebrate.     

Are there changes in postural regulation across the lifespan?

Abstract

The purpose was to obtain parameters of postural regulation (n?=?1724) of asymptomatic subjects (6–97 years). The maximum postural stability and capacity of postural subsystems were calculated for the age ranges from 34 to 35 years (men) and from 38 to 44 years (women). A significant decline in postural performance was observed in the 40s (men) and 50s (women). Data can be used in the evaluation of dizziness and balance disorders in people of all ages.     

Are there ecological implications for the proposed energetic restrictions on photosynthetic oxygen evolution at high oxygen concentrations?

It has recently been shown that, in subthylakoid particles prepared using detergent, there is inhibition of oxygen production reactions in photosynthesis by thermodynamic feedback from oxygen build-up, with 50% inhibition at 230 kPa partial pressure of oxygen. This article presents a comprehensive analysis of laboratory data on the effects of high oxygen partial pressures on photosynthesis, and on photo-lithotrophic and chemo-organotrophic growth, of oxygen-producing organisms. The article also contains an analysis of the extent to which high oxygen concentrations occur at the site of photosystem II (PSII) activity under natural conditions today and in the past. The conclusion is that the oxygen concentrations found in nature are very unlikely to reach that needed to cause 50% inhibition of the photosynthetic oxygen production reaction in subthylakoid particles, but that it is just possible that a small part of the inhibition of photosynthesis and of photo-lithotrophic growth by oxygen can be attributed to inhibition of oxygen production by PSII.     

Exploiting the apoptotic process for management of HIV: Are we there yet?

CD4⁺ T cells die in individuals infected with HIV, either as a result of direct HIV infection or as uninfected innocent bystanders. Possible mechanisms for bystander killing include generation of viral products such as Tat or gp120 and expression of death receptor ligands, such as FasL, that engage functional death receptors on uninfected cells. This review covers the sometimes conflicting in vitro and ex vivo studies that address these possible mechanisms of HIV-associated cell death. It is an intriguing possibility that manipulation of cell death processes, to decrease bystander death or increase death of infected cells, in patients infected with HIV might provide a useful adjunct to antiretroviral therapy.     

Are Long-Lasting Insecticidal Nets Effective for Preventing Childhood Deaths among Non-Net Users? A Community-Based Cohort Study in Western Kenya

Background

Increasing the distribution and use of insecticide-treated nets (ITNs) in Sub-Saharan Africa has made controlling malaria with ITNs more practical. We evaluated community effects induced by ITNs, specifically long-lasting insecticidal nets (LLINs), under ordinary conditions in an endemic malaria area of Western Kenya.

Methods

Using the database from Mbita Health and Demographic Surveillance System (HDSS), children younger than 5 years old were assessed over four survey periods. We analyzed the effect of bed net usage, LLIN density and population density of young people around a child on all-cause child mortality (ACCM) rates using Cox PH models.

Results

During the study, 14,554 children were followed and 250 deaths were recorded. The adjusted hazard ratios (HRs) for LLIN usage compared with no net usage were not significant among the models: 1.08 (95%CI 0.76–1.52), 1.19 (95%CI 0.69–2.08) and 0.92 (95%CI 0.42–2.02) for LLIN users, untreated net users, and any net users, respectively. A significant increasing linear trend in risk across LLIN density quartiles (HR = 1.25; 95%CI 1.03–1.51) and a decreasing linear trend in risk across young population density quartiles among non-net user children (HR = 0.77; 95%CI 0.63–0.94) were observed.

Conclusions

Although our data showed that current LLIN coverage level (about 35%) could induce a community effect to protect children sleeping without bed nets even in a malaria-endemic area, it appears that a better system is needed to monitor the current malaria situation globally in order to optimize malaria control programs with limited resources.     

Are there new possibilities in immunomorphology?

Immunomorphology, including immunohistochemistry and immunocytochemistry, forms a category of well known, reproducible, cost and environment saving immunodiagnostic methods based on immunological specificity. Both the accurate diagnosis and a better knowledge of biological parameters of diseases, especially of malignant tumors, result from the continual development of technologies and applications concerning at least 60 years of history of immunostaining. This review attempts to summarize the most important steps of development of immunomorphology.     

Biofilms and Biocides: Are there Implications for Antibiotic Resistance?

Considerable controversy surrounds the use of biocides in an ever increasing range of consumer products and the possibility that their indiscriminate use might reduce biocide effectiveness and alter susceptibilities towards antibiotics. These concerns have been based largely on the isolation of resistant mutants from in vitro monoculture experiments. To date, however the emergence of biocide-resistant strains in-vivo has not been reported and a number of environmental survey studies have failed to associate biocide use with antibiotic resistance. This article gives an overview of the issues as they currently stand and reviews data generated in our laboratory over the last five years where we have used laboratory microcosms of the environment and oral cavity to better understand the possible effects of real-life biocide exposure of these high risk ecosystems. In general, whilst biocide susceptibility changes can be demonstrated in pure culture, especially for E. coli towards triclosan, it has not been possible to reproduce these effects during chronic, sublethal dosing of complex communities. We conclude from this review that whilst the incorporation of antibacterial agents into a widening sphere of personal products may not overtly impact on the patterns of microbial susceptibility observed in the environment, the precautionary principle suggests that the use of biocides should be limited to applications where clear hygienic benefits can be demonstrated.     

Are there mappable genes for family resemblance for the magnitude of intra-individual variation in systolic blood pressure?

Background

The genetic regulation of variation in intra-individual fluctuations in systolic blood pressure over time is poorly understood. Analysis of the magnitude of the average fluctuation of a person's systolic blood pressure around his or her age-adjusted trend line, however, shows moderate, albeit significant, family resemblance in Cohort 1 of the Framingham Heart Study. To determine whether genomic regions affecting this phenotype could be identified, we pursued a "model-free" multipoint quantitative linkage analysis.

Results

Two different linkage methods revealed multiple nominally significant signals, two to four of which are "replicated" in Cohort 2. When both cohorts are assembled into extended pedigrees, three linkage signals remain nominally significant by one or both methods.

Conclusion

Any or all of the genomic regions in the vicinity of D5S1456, D11S2359, and D20S470 may contain elements that regulate systolic blood pressure homeostasis.

     

Are there specialized junctions in the pars maculata of the distal tubule?

Summary In the present study the tight junctions at the macula densa were compared to those of the adjacent straight and convoluted segments of the distal tubule using freeze fracturing and thin sectioning techniques. Only insignificant differences were found in the number of strands and the apico-basal depth of the tight junctions in the three distal tubular segments of rat, dog and tree shrew. In experiments with horseradish peroxidase on mice and tree shrews, the tracer did not penetrate the apical junctions in any of the distal tubular segments. Our findings do not support the concept of considerably higher permeability of the tight junctions at the macula densa, as previously reported. Gap junctions were never observed in the distal nephron. The present results suggest that the glomerulo-tubular feedback is more likely to be mediated by transcellular resorption of solutes than by passive diffusion through a leaky paracellular shunt pathway.These studies were supported by the German Research Foundation within the SFB 90 Cardiovasculäres System