Genetic dereplication of Trichoderma hypoxylon reveals two novel polycyclic lactones

Previous study demonstrated large scale production of trichochecenes which limited the discovery of novel metabolites in Trichoderma hypoxylon. By genetic deletion of trichothecene synthase encoding gene thtri5, we created the dereplication mutant which eliminated the production of trichothecenes. Through chemical isolation, we characterized a couple of rare new polycyclic lactones tricholactones A and B from the thtri5 deletion strain. The structures of these two compounds were well determined by NMR, HR-ESI-MS and IECD analysis.     

Maximum Likelihood Estimation of Genetic Parameters in Cell Populations

In this paper we consider a cell population such as bacteria consisting of two types of cells, mutant and nonmutant. Under the mutation and homogeneous pure birth processes, this paper derives a maximum likelihood estimation procedure for estimating mutation rate and birth rate. The method is applied to Newcombe's data; further some Monte Carlo studies are generated. The numerical results indicate that the method is quite efficient for estimating genetic parameters in cell populations.     

Responses of rain-forest primates to habitat disturbance: A review

The survival of primates in moderately disturbed forests is determined by a complex of variables. Correlation analyses suggest that ecological features of a species may confer a basal survival ability but that details of the form of disturbance may be crucially important. Correlation analyses reveal that body size alone is a poor predictor of primate response to moderate forest disturbance. However, when the effects of diet variables are held constant, body size more strongly correlates with survival ability (smaller species surviving better). Degree of frugivory shows a significant negative correlation with survival ability at both univariate and multivariate levels of analysis. In contrast, dietetic diversity is not correlated with survival ability at either level of analysis. Together, body size and percentage frugivory explain 44% of the variation in species’ responses to moderate habitat disturbance. Idiosyncratic responses of species can usually be traced to specific features of the changing environment, such as selective elimination of important food sources and, conversely, the presence of increased densities of particular food sources arising from the disturbance.     

Expected early genetic gain from selection for milk yield in dairy cattle

Summary A matrix program to predict short term genetic gain from single trait selection for milk yield was developed. Rate of genetic gain was calculated as the annual change in the mean breeding value of all producing females. Several parameters sets representing various selection policies were used to examine situations pertinent to dairy populations of the United States. Approach to the asymptotic rates of genetic gain within the model varied with the choice of parameters, but even with consistent selection policies, predicted total genetic gain in the first 10 years was only half of the expected from classical theory. Considerable year to year variation in the rate of gain occurred. Early gains were more dependent on female selection decisions than gains during the steady state. In a two-phase model, the approach to the linear rate of gain in the second phase was accelerated by starting with an ongoing improvement program, but considerable delays still existed. Selection for sex- limited traits such as milk yield, which require pedigree selection and a waiting time for progeny test results reached asymptotic rates more slowly than previously assumed.     

Links between global taxonomic diversity,ecological diversity and the expansion of vertebrates on land

Tetrapod biodiversity today is great; over the past 400 Myr since vertebrates moved onto land, global tetrapod diversity has risen exponentially, punctuated by losses during major extinctions. There are links between the total global diversity of tetrapods and the diversity of their ecological roles, yet no one fully understands the interplay of these two aspects of biodiversity and a numerical analysis of this relationship has not so far been undertaken. Here we show that the global taxonomic and ecological diversity of tetrapods are closely linked. Throughout geological time, patterns of global diversity of tetrapod families show 97 per cent correlation with ecological modes. Global taxonomic and ecological diversity of this group correlates closely with the dominant classes of tetrapods (amphibians in the Palaeozoic, reptiles in the Mesozoic, birds and mammals in the Cenozoic). These groups have driven ecological diversity by expansion and contraction of occupied ecospace, rather than by direct competition within existing ecospace and each group has used ecospace at a greater rate than their predecessors.     

Flavonoid diversity and endemism in Arnica subgenus Austromontana

Eighty-seven populations, representing eight species of Amica subgenus Austromontana, were examined for flavonoids. A total of 22 compounds, including simple and methylated flavone and flavonol glycosides as well as methylated aglycones, were isolated and identified. The two widespread species, A. cordifolia and its presumed early derivative A. latifolia, are ancestral species of the subgenus. From these two species, major evolutionary diversification within the subgenus has taken place largely in the Klamath region of Oregon and California, resulting in the formation of several rare, endemic species. These endemics are generally characterized by reduced flavonoid profiles and/or an increase in the number of methylated aglycones while, in contrast, the wider ranging species have few methylated aglycones and more glycosides. However, one species, A. viscosa, a rare volcanic endemic, exhibits the most elaborate and specialized flavonoid profile within the subgenus.     

Human Equilibrative Nucleoside Transporter-3 (hENT3) Spectrum Disorder Mutations Impair Nucleoside Transport,Protein Localization,and Stability

Accumulating evidence reveals that sole mutations in hENT3 cause a spectrum of human genetic disorders. Among these include H syndrome, characterized by scleroderma, hyperpigmentation, hypertrichosis, hepatomegaly, cardiac abnormalities and musculoskeletal deformities, pigmented hypertrichotic dermatosis with insulin-dependent diabetes syndrome, characterized by autoantibody-negative diabetes mellitus and skin deformities, familial Rosai-Dorfman disease, characterized by short stature, familial histiocytosis and sinus histiocytosis with massive lymphadenopathy (SHML), characterized by severe tissue infiltration of immune cells and swollen lymph nodes. hENT3 spectrum disorders share a common mutation and share overlapping clinical manifestations that display many intriguing resemblances to mitochondrial and lysosomal disorders. Although earlier studies identify hENT3 as a mitochondrial and a lysosomal nucleoside transporter, the precise connections between hENT3 and the pathophysiology of these disorders remain unresolved. In this study, we performed functional and biochemical characterization of these mutations in hENT3. We report severe reductions/losses of hENT3 nucleoside transport functions of hENT3 syndrome mutants. In addition to transport alterations, we provide evidence for possible loss of hENT3 functions in all H and pigmented hypertrichotic dermatosis with insulin-dependent diabetes syndromes due to either mistrafficking or altered stability of mutant hENT3 proteins.     

Improved viability of populations with diverse life-history portfolios

A principle shared by both economists and ecologists is that a diversified portfolio spreads risk, but this idea has little empirical support in the field of population biology. We found that population growth rates (recruits per spawner) and life-history diversity as measured by variation in freshwater and ocean residency were negatively correlated across short time periods (one to two generations), but positively correlated at longer time periods, in nine Bristol Bay sockeye salmon populations. Further, the relationship between variation in growth rate and life-history diversity was consistently negative. These findings strongly suggest that life-history diversity can both increase production and buffer population fluctuations, particularly over long time periods. Our findings provide new insights into the importance of biocomplexity beyond spatio-temporal aspects of populations, and suggest that maintaining diverse life-history portfolios of populations may be crucial for their resilience to unfavourable conditions like habitat loss and climate change.