Dynamic Ligand Discrimination in the Notch Signaling Pathway

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The effect of environmental conditions on Atlantic salmon smolts’ (<Emphasis Type="Italic">Salmo salar</Emphasis>) bioenergetic requirements and migration through an inland sea

The timing of the juvenile Atlantic salmon ocean-entry is considered a critical stage in the species’ life-history. Entry into the ocean at suboptimal times can have negative survival impacts on entire smolt cohorts. Previous studies have identified smolt residency time in the Bras d’Or Lakes as highly variable and correlated with body condition. This study combines energetic modelling using Dynamic Energy Budget (DEB) theory with acoustic telemetry to mechanistically link smolt bioenergetics to their migration strategy within the Bras d’Or. This study examines two main questions: 1) what is the relationship between smolts’ bioenergetics and smolts’ migration strategy, and 2) what effect would warmer water temperature have on smolts’ energetic requirements? Simulation results indicate that smolts requiring more food are more likely to exit the Bras d’Or during the observation period. The results also suggest higher lake temperature would result in faster depletion of smolt energy reserves, which is predicted to favour smolts migrating to the ocean sooner.     

UDP-Glucose: (1,3)-beta-Glucan Synthase from Daucus carota L. : Characterization, Photoaffinity Labeling, and Solubilization

The membrane-bound UDP-glucose-β-(1,3)-glucan synthase from Daucus carota L. was characterized and a solubilization procedure was developed. The enzyme exhibited maximal activity in the presence of 0.75 millimolar Ca²⁺, 0.5 millimolar EGTA, and 5 millimolar cellobiose at pH 7.5 and 30°C at 1 millimolar UDPG. Reaction products were confirmed to be (1,3)-linked glucan. Polypeptides of 150, 57, and 43 kilodaltons were labeled with the photoactivatible affinity label 5-azido-uridine 5′-β-[³²P] diphosphateglucose. Labeling of the 150 and 57 kilodalton polypeptides was completely protected against by 1 millimolar non-radioactive UDPG suggesting that one or both of these polypeptides may represent the UDPG binding subunit of glucan synthase. Carrot glucan synthase was solubilized with the detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS) in the absence of divalent cations and chelators; however, the percentage of enzyme which could be solubilized showed variability with membrane source. With microsomal membranes, up to 80% of the enzyme was released with 0.7% CHAPS. Solubilized enzyme was stable for at least 9 hours at 4°C. When more highly purified membrane fractions were isolated from sucrose step gradients a slightly different picture emerged. Activity from the 20/30% interface (Golgi and tonoplast enriched) was readily solubilized and expressed. Activity from the 30/40% interface (plasma membrane enriched) was also solubilized; however, it was necessary to add heat inactivated microsomes to assay mixtures for full activity to be expressed. A requirement for endogenous activators is suggested.     

Sibling recognition in the prairie vole, Microtus ochrogaster

Since mating is seldom observed between sibling prairie voles, Microtus ochrogaster, this, behavioural discrimination was used to investigate sibling recognition in this species. Cross-fostering of 1–3-day-old pups demonstrated that unrelated pups reared together did not breed, whereas siblings reared apart bred readily when paired at weaning. When unrelated voles were paired at 14 days of age, prior to sexual maturity, significantly fewer pairs bred than when strangers were paired at 21 days of age. Separation of 21-day-old siblings for 8 days before pairing overcame incest avoidance; a 15-day separation was required for breeding by siblings that had remained together until they were 50 days old. These results indicate that sibling recognition and, consequently, incest avoidance depend on association prior to weaning.     

The collaborative study on the genetics of alcoholism: Genetics

This review describes the genetic approaches and results from the family-based Collaborative Study on the Genetics of Alcoholism (COGA). COGA was designed during the linkage era to identify genes affecting the risk for alcohol use disorder (AUD) and related problems, and was among the first AUD-focused studies to subsequently adopt a genome-wide association (GWAS) approach. COGA's family-based structure, multimodal assessment with gold-standard clinical and neurophysiological data, and the availability of prospective longitudinal phenotyping continues to provide insights into the etiology of AUD and related disorders. These include investigations of genetic risk and trajectories of substance use and use disorders, phenome-wide association studies of loci of interest, and investigations of pleiotropy, social genomics, genetic nurture, and within-family comparisons. COGA is one of the few AUD genetics projects that includes a substantial number of participants of African ancestry. The sharing of data and biospecimens has been a cornerstone of the COGA project, and COGA is a key contributor to large-scale GWAS consortia. COGA's wealth of publicly available genetic and extensive phenotyping data continues to provide a unique and adaptable resource for our understanding of the genetic etiology of AUD and related traits.     

Introduction and integration of strangers into captive groups of tufted capuchins (Cebus apella)

We introduced two to four unfamiliar animals into three established groups (N = 6–9 per group) of tufted capuchins (Cebus apella).We present findings on the behavioral consequences of introductions as a function of age, sex, and residency status and long-term consequences for health and reproduction. No morbidity from aggression occurred at the time of introductions or during several months following, and reproduction was not compromised. Activity budgets and patterns of social spacing and interaction were little changed following the introductions except for increases in vigilance behavior, especially by newly introduced adult females. Adult females exhibited the strongest and longest-lasting response to changes in group composition. The results indicate that in this species (1) introductions of adult females can be carried out with acceptable risk to the newcomers provided that careful monitoring occurs, so that the onset of severe aggression instigated by resident females toward new females can be avoided, (2) juveniles can be introduced with minimal risk, and (3) adult males can be introduced into groups lacking resident adult males with minimal risk. Capuchins differ in important ways from the better-studied Old World monkeys in their response to introductions of strangers. The differences are instructive with regard to processes supporting species-typical social structure, which is less overtly hierarchical in capuchins than in macaques.     

Identification of Novel Temperature-sensitive Lethal Alleles in Essential β-Tubulin and Nonessential α2-Tubulin Genes as Fission Yeast Polarity Mutants

We have screened for temperature-sensitive (ts) fission yeast mutants with altered polarity (alp1–15). Genetic analysis indicates that alp2 is allelic to atb2 (one of two α-tubulin genes) and alp12 to nda3 (the single β-tubulin gene). atb2⁺ is nonessential, and the ts atb2 mutations we have isolated are dominant as expected. We sequenced two alleles of ts atb2 and one allele of ts nda3. In the ts atb2 mutants, the mutated residues (G246D and C356Y) are found at the longitudinal interface between α/β-heterodimers, whereas in ts nda3 the mutated residue (Y422H) is situated in the domain located on the outer surface of the microtubule. The ts nda3 mutant is highly sensitive to altered gene dosage of atb2⁺; overexpression of atb2⁺ lowers the restrictive temperature, and, conversely, deletion rescues ts. Phenotypic analysis shows that contrary to undergoing mitotic arrest with high viability via the spindle assembly checkpoint as expected, ts nda3 mutants execute cytokinesis and septation and lose viability. Therefore, it appears that the ts nda3 mutant becomes temperature lethal because of irreversible progression through the cell cycle in the absence of activating the spindle assembly checkpoint pathway.     

Integrating Indigenous Resource Management with Wildlife Conservation: A Case Study of Batang Ai National Park, Sarawak, Malaysia

This paper examines the indigenous land and forest management systems of the community of seven Iban longhouses whose territories comprise the area of Batang Ai National Park in Sarawak, Malaysia. It also discusses the integrated conservation and development program (ICDP) at the park. This project is attempting to work within the existing system of customary law to build on traditional legislative infrastructure and management practices, in order to enlist the cooperation of local people and their leaders in implementing a new conservation strategy. In addition to reinforcing local authority, park planners recognize the need for local people to be given strong incentives to participate in co-management of the protected area. This paper argues that, despite a history of conflict with indigenous peoples, State officials have in this instance demonstrated a willingness to work with local people and community leaders. At the same time, they are encouraging community development, helping people to find alternatives to activities that threaten the park's wildlife.