Application of photosynthetic N2-fixing cyanobacteria to the CELSS program

Commercially available air lift fermentors were used to simultaneously monitor biomass production, N2-fixation, photosynthesis, respiration, and sensitivity to oxidative damage during growth under various nutritional and light regimes, to establish a data base for the integration of these organisms into a Closed Ecological Life Support System (CELSS) program. Certain cyanobacterial species have the unique ability to reduce atmospheric N2 to organic nitrogen. These organisms combine the ease of cultivation characteristics of prokaryotes with the fully developed photosynthetic apparatus of higher plants. This, along with their ability to adapt to changes in their environment by modulation of certain biochemical pathways, make them attractive candidates for incorporation into the CELSS program

Cyanobacteria in CELSS: Growth strategies for nutritional variation and nitrogen cycling

Cyanobacteria (blue-green algae) are versatile organisms which are capable of adjusting their cellular levels of carbohydrate, protein, and lipid in response to changes in the environment. Under stress conditions there is an imbalance between nitrogen metabolism and carbohydrate/lipid synthesis. The lesion in nitrogen assimilation is at the level of transport: the stress condition diverts energy from the active accumulation of nitrate to the extrusion of salt, and probably inhibits a cold-labile ATP'ace in the case of cold shock. Both situations affect the bioenergetic status of the cell such that the nitrogenous precursors for protein synthesis are depleted. Dispite the inhibition of protein synthesis and growth, photosynthetic reductant generation is relatively unaffected. The high O2 reductant would normally lead to photo-oxidative damage of cellular components; however, the organism copes by channeling the 'excess' reductant into carbon storage products. The increase in glycogen (28 to 35 percent dry weight increase) and the elongation of lipid fatty acid side chains (2 to 5 percent dry weight increase) at the expense of protein synthesis (25 to 34 percent dry weight decrease) results in carbohydrate, lipid and protein ratios that are closer to those required in the human diet. In addition, the selection of nitrogen fixing mutants which excrete ammonium ions present an opportunity to tailor these micro-organisms to meet the specific need for a sub-system to reverse potential loss of fixed nitrogen material

Produção de leite e comportamento de amamentação em cinco sistemas de produção de gado de corte.

Foram estudados a producao de letie de vacas Nelore e o comportamento de amamentacao em diferentes sistemas de producao NR-Nelore Referencia

Impact of facial conformation on canine health: Brachycephalic Obstructive Airway Syndrome

The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring

Impact of sequential surface-modification of graphene oxide on ice nucleation

Base-washed graphene-oxide which has been sequentially modified by thiol-epoxy chemistry, results in materials with ice nucleation activity. The role of hydro-philic/phobic grafts and polymers was evaluated with the most potent functioning at just 0.25 wt %. These 2-D hybrid materials may find use in cryopreservation and fundamental studies on ice formation

Some non genetic effects on pre and pos-weaning weights of Canchim calves.

Some non genetic effects on pre and pos-weaning weights of Canchim calves

Identificação dos fatores de riscos do ecossistema na maternidade por meio de análise de correspondência. I. Diarréias.

Na suinocultura intensiva as doenças são causa de prejuízo. Estas doenças tem origem multifatoriais inter-relacionadas e de etiologia complexa, podendo no entanto serem compreendidas por meios de estudos ectopatológicos.Resumo

Causas de variação de pesos e ganhos de peso em fêmeas da Raça Canchim

Causas de variação e estimativas dos coeficientes de herdabilidade e correlações genética relativos aos pesos ao nascer, aos 205 aos 12, 18 e 24 meses

Emprego do babaçu (Orbignya phalerata) como fonte energética para caititus (Pecari tajacu).

O objetivo foi estudar o emprego de babaçu integral e torta de babaçu, como fontes energéticas substituindo parte do milho na alimentação do caititu (Pecari tajacu) em sistemas de cativeiro. No experimento-I, avaliou-se o desempenho de 12 animais, testando-se o babaçu integral em rações de mantença. No experimento-II avaliou-se o desempenho de 12 animais, testando-se a torta de babaçu em rações de terminação. Os mesmos foram abatidos para análise de carcaças. Avaliaram-se rendimento, composição, medidas, órgãos, glândulas e cortes comerciais. O Ganho diário de peso (GDP) e consumo diário de ração (CDR) dos animais que receberam babaçu integral, diminuíram quando a proporção do babaçu aumentou. Até 25% de inclusão do mesmo, obtiveram CDR satisfatório. Considerando-se a disponibilidade e custo reduzido do babaçu integral na Amazônia comparando-o ao milho, sugere-se até 25% de babaçu integral em rações de caititus em mantença. Embora não foi observada nenhuma diferença significativa (P> 0,05) dos níveis de farelo de babaçu sobre o ganho médio diário eo consumo médio diário de ração, os resultados mostram bom desempenho em 40% de torta na ração de caititus em fase de terminação. Houve uma tendência para bons GDP, consumo, rendimentos de carcaça e cortes comerciais em 40% de torta de babaçu, sugerindo-a como alternativa energética substituindo o milho em rações para caititus na fase de terminação