Systematic approaches to assessing high-temperature limits to fertility in animals.

Critical thermal limits (CTLs) gauge the physiological impact of temperature on survival or critical biological function, aiding predictions of species range shifts and climatic resilience. Two recent Drosophila species studies, using similar approaches to determine temperatures that induce sterility (thermal fertility limits [TFLs]), reveal that TFLs are often lower than CTLs and that TFLs better predict both current species distributions and extinction probability. Moreover, many studies show fertility is more sensitive at less extreme temperatures than survival (thermal sensitivity of fertility [TSF]).

Sourdough "Biga" Fermentation Improves the Digestibility of Pizza Pinsa Romana: An Investigation through a Simulated Static In Vitro Model.

Baked goods manufacturing parameters and fermentation conditions interfere with the nutrients content and affect their gastrointestinal fate. Pinsa Romana is a type of pizza that, recently, has been commercially rediscovered and that needed elucidation from a nutritional and digestibility perspective. In this study, six types of Pinsa Romana (five made with indirect method and one produced with straight dough technology) were characterized for their biochemical and nutritional features.

Rodent mothers increase vigilance behaviour when facing infanticide risk.

Infanticide, the killing of unrelated young, is widespread and frequently driven by sexual conflict. Especially in mammals with exclusive maternal care, infanticide by males is common and females suffer fitness costs. Recognizing infanticide risk and adjusting offspring protection accordingly should therefore be adaptive in female mammals.

Correction: Genetic introgression among differentiated clades is lower among clades exhibiting different parity modes.

The original version of this Article contained an error in the spelling of the author Y. Surget-Groba, which was incorrectly given as J. Surget-Groba.

Genetic introgression among differentiated clades is lower among clades exhibiting different parity modes.

Mechanisms leading to sympatric speciation are diverse and may build up reproductive isolation. Reproductive isolation among differentiated clades may exist due to genetic incompatibilities, sexual selection, differences in parity mode, reduced post-zygotic survival or reproductive success of hybrids. Here, we test whether differences in parity mode lead to reproductive isolation by investigating introgression in Zootoca vivipara, a lizard species exhibiting oviparous and viviparous reproduction.

Climate Effects on Growth, Body Condition, and Survival Depend on the Genetic Characteristics of the Population.

Climatic change is expected to affect individual life histories and population dynamics, potentially increasing vulnerability to extinction. The importance of genetic diversity has been highlighted for adaptation and population persistence. However, whether responses of life-history traits to a given environmental condition depend on the genetic characteristics of a population remains elusive.

Inter-class competition in stage-structured populations: effects of adult density on life-history traits of adult and juvenile common lizards.

Ecological and evolutionary processes in natural populations are largely influenced by the population's stage-structure. Commonly, different classes have different competitive abilities, e.g.

Experimental evidence that sperm maturation drives protandry in an ectotherm.

Protandry, i.e., the earlier arrival to breeding areas of males than females, has attracted a lot of scientific attention.

Microhabitat selection in the common lizard: implications of biotic interactions, age, sex, local processes, and model transferability among populations.

Modeling species' habitat requirements are crucial to assess impacts of global change, for conservation efforts and to test mechanisms driving species presence. While the influence of abiotic factors has been widely examined, the importance of biotic factors and biotic interactions, and the potential implications of local processes are not well understood. Testing their importance requires additional knowledge and analyses at local habitat scale.

Mutational analysis of exopolysaccharide biosynthesis by Lactobacillus sakei 0-1.

Lactobacillus sakei strain 0-1 produces an exopolysaccharide (EPS) consisting of glucose and rhamnose in a ratio of 3:2. As part of a biochemical and molecular analysis of the EPS biosynthetic pathway in L. sakei strain 0-1, we have isolated a random set of EPS-negative mutants.

A novel cyclic beta-1,2-glucan mutant of Rhizobium meliloti.

The periplasmic cyclic beta-1,2-glucans produced by bacteria within the Rhizobiaceae family provide functions during hypo-osmotic adaptation and plant infection. In Rhizobium meliloti, these molecules are highly modified with phosphoglycerol and succinyl substituents, and it is possible that the anionic character of these glucans is important for their functions. In the present study, we have used a thin-layer chromatographic screening method to identify a novel R.

Effect of Phosphate Limitation on Synthesis of Periplasmic Cyclic (beta)-(1,2)-Glucans.

Rhizobium meliloti and Agrobacterium tumefaciens synthesize periplasmic cyclic (beta)-(1,2)-glucans during adaptation to hypoosmotic environments. It also appears that these glucans provide important functions during the interactions of these bacteria with plant hosts. A large fraction of these glucans may become modified with anionic substituents such as phosphoglycerol or succinic acid; however, the role(s) of these substituents is unknown.

Synthesis of glycerophosphorylated cyclic (1,2)-beta-glucans in Rhizobium meliloti strain 1021 after osmotic shock.

The transfer of phosphoglycerol moieties from phosphatidylglycerol to the cyclic (1,2)-beta-glucans in growing cultures of Rhizobium meliloti strain 1021 was investigated using pulse-chase experiments with [3H]glycerol and/or [14C]glucose. No transfer occurred when cells were grown and pulse-chased in a medium containing 0.4 M NaCl.

Cyclic beta-glucans of members of the family Rhizobiaceae.

Cyclic beta-glucans are low-molecular-weight cell surface carbohydrates that are found almost exclusively in bacteria of the Rhizobiaceae family. These glucans are major cellular constituents, and under certain culture conditions their levels may reach up to 20% of the total cellular dry weight. In Agrobacterium and Rhizobium species, these molecules contain between 17 and 40 glucose residues linked solely by beta-(1,2) glycosidic bonds.

Synthesis of glycerophosphorylated cyclic beta-(1,2)-glucans by Rhizobium meliloti ndv mutants.

The periplasmic cyclic beta-(1,2)-glucans of Rhizobium spp. are believed to provide functions during hypoosmotic adaptation and legume nodulation. In Rhizobium meliloti, cyclic beta-(1,2)-glucans are synthesized at highest levels when cells are grown at low osmolarity, and a considerable fraction (> or = 35%) of these glucans may become substituted with phosphoglycerol moieties.

Polysaccharide synthesis in relation to nodulation behavior of Rhizobium leguminosarum.

In this study, we characterized four Tn5 mutants derived from Rhizobium leguminosarum RBL5515 with respect to synthesis and secretion of cellulose fibrils, extracellular polysaccharides (EPS), capsular polysaccharides, and cyclic beta-(1,2)-glucans. One mutant, strain RBL5515 exo-344::Tn5, synthesizes residual amounts of EPS, the repeating unit of which lacks the terminal galactose molecule and the substituents attached to it. On basis of the polysaccharide production pattern of strain RBL5515 exo-344::Tn5, the structural features of the polysaccharides synthesized, and the results of an analysis of the enzyme activities involved, we hypothesize that this strain is affected in a galactose transferase involved in the synthesis of EPS only.

Influence of growth conditions on production of capsular and extracellular polysaccharides by Rhizobium leguminosarum.

The influence of growth rate and medium composition on exopolymer production by Rhizobium leguminosarum was studied. When grown in medium containing 10 g/l mannitol and 1 g/l glutamic acid, Rhizobium leguminosarum biovar trifolii TA-1 synthesized up to 2.0 g/l of extracellular polysaccharide (EPS), and up to 1.

Synthesis of cyclic beta-(1,2)-glucans by Rhizobium leguminosarum biovar trifolii TA-1: factors influencing excretion.

The synthesis of cyclic beta-(1,2)-glucans from UDP-[14C]glucose by a crude membrane preparation and whole cells of Rhizobium leguminosarum bv. trifolii TA-1 was investigated. The crude membrane system needed Mn2+, ATP, and NAD+ for optimal activity.

Unusual structure of the exopolysaccharide of Rhizobium leguminosarum bv. viciae strain 248.

The exopolysaccharide from R. leguminosarum bv. viciae strain 248 differs from those of other Rhizobium strains with similar symbiotic behavior.

Rhizobium leguminosarum exoB mutants are deficient in the synthesis of UDP-glucose 4'-epimerase.

Rhizobium leguminosarum bv. viciae Exo- mutant strains RBL5523,exo7::Tn5,RBL5523,exo8::Tn5 and RBL5523,exo52::Tn5 are affected in nodulation and in the syntheses of lipopolysaccharide, capsular polysaccharide, and exocellular polysaccharide. These mutants were complemented for nodulation and for the syntheses of these polysaccharides by plasmid pMP2603.

Excessive excretion of cyclic beta-(1,2)-glucan by Rhizobium trifolii TA-1.

At 25 degrees C, the optimal temperature for growth of Rhizobium trifolii TA-1, extracellular and capsular polysaccharide (EPS and CPS) were the main carbohydrate products synthesized in mannitol-rich medium (10 g of mannitol and 1 g of glutamic acid per liter). In the same medium at 33 degrees C, EPS and CPS production was inhibited, and up to 3.9 g of cyclic beta-(1,2)-glucan was produced during an incubation period of 20 days with a total biomass of 0.

The role of carotenoids in preventing oxidative damage in the pigmented yeast, Rhodotorula mucilaginosa.

Rhodotorula mucilaginosa is an obligate aerobic yeast which contains a high concentration of carotenoid pigment. To test whether carotenoids are able to protect R. mucilaginosa against oxidative injury, yeast cells in liquid culture were incubated with duroquinone (DQ) (100 microM), a redox-cycling quinone known to generate intracellular O2-.