Kombucha Leather Durability: Sugar Concentration\u27s Effect on Bacterial Cellulose

Due to its rising popularity many people may now know of kombucha; A fermented tea beverage thought to have originated long ago in the region that is now known as China. Through the same process that this familiar beverage is made, there is also the less familiar production of a polymeric bacterial cellulose pellicle that floats on the surface of the culture. This and other forms of bacterial cellulose are the subject of research for several different applications. Bacterial cellulose has potential for use in medicine, textiles, and as a food additive. The tensile strength of kombucha’s leather-like material grown in different sugar concentrations was measured and statistically analyzed. The groups grown in higher sugar concentrations were found to withstand significantly more force before tearing than those grown in low sugar concentrations. Photographs of the pellicles of each group were also taken and compared at 400x magnification

Dietary and body mass thresholds for reproduction in grasshoppers

An organism’s dietary protein should match its respective dietary needs to yield the most advantageous effects; an extended lifespan and increased reproductive output. The key challenge however, is how to tailor a specific diet to an organism’s individual needs. Applying the technique of Piper et. al, we can approximate the optimal diet of the lubber grasshopper, Romalea microptera, by using the AA profile of vitellogenin (Vg), the precursor to egg yolk protein. The lubber grasshopper, Romalea microptera, was selected because of its plasticity in reproductive responsiveness in response to diet quality and quantity. Each of the organisms were fed 1g of romaine lettuce, ad libitum (ad-lib) zero protein high carbohydrate artificial diet and a different experimentally manipulated diet. The 4 treatment groups, Vg-balanced AA, unbalanced AA, ad-lib lettuce, and dietary restriction (DR), dietary treatments were applied twice daily from day 2 of adulthood to egg laying. The experimental group was force-fed the balanced AA diet, which was derived from the AA composition of vitellogenin. The unbalanced AA group was fed an isonitrogenous diet with over representations of AA’s found in romaine. The ad lib group had unlimited access to romaine and was force-fed PBS. The DR group was fed a diet comprising of 1 gram of romaine and PBS. The results indicated ad-lib group had the highest yield, followed by Vg-balanced, unbalanced, and DR . In contrast, somatic mass and storage did not differ across 3 groups fed 1gm lettuce daily. Isonitrogenous diets exhibited difference in reproduction but not somatic growth

Life-extending ovariectomy in grasshoppers increases somatic storage, but dietary restriction with an equivalent feeding rate does not

Reduced diet or reduced reproduction each extends lifespan in many animals. It is often thought that reduced reproduction and reduced diet may act through the same mechanisms. In grasshoppers, ovariectomy extends lifespan and reduces feeding to a level similar to that used for life extension by dietary restriction, further suggesting mechanistic overlap. Here, we measure the feeding rate of ovariectomized grasshoppers and, by manipulating feeding levels, create a sham-operated & dietary restricted group with matched daily feeding. Both groups show ~25% increased survivorship near the median age of mortality for fully fed and reproductive controls. Ovariectomy results in a doubling of fat body mass and hemolymph volume in comparison to both a feeding-matched dietary restriction group and a sham-operated & fully fed control, which do not differ from each other. Total anti-oxidant activity in the hemolymph and the skeletal muscle was unchanged upon ovariectomy or dietary restriction, so it does not appear to be a major factor in lifespan extension. Next, we measured mitochondrial counts using qPCR to determine mitochondrial cytochrome-b concentrations relative to nuclear (genomic) beta-actin. Mitochondrial counts in the ovariectomized group were lower than sham-operated and fully fed controls but not than the dietary restriction group. Last, in the fat body, transcript levels of hexamerin-90 (a hemolymph storage protein) were affected by neither ovariectomy nor dietary restriction. Hence, ovariectomy resulted in large magnitude increases in organismal storage. The matched-fed dietary restricted group differed from the ovariectomized group only in organismal storage, and not in any of the cellular parameters measured here. This study suggests that longevity via ovariectomy has distinct physiological mechanisms from longevity via dietary restriction in grasshoppers that are independent of daily feeding rate, particularly for protein and fat storage

Thermal constraints for range expansion of the invasive green mussel, Perna viridis, in the southeastern United States

https://digitalcommons.library.umaine.edu/mmb-vp-copyright/5738/thumbnail.jp