Fluid‐preserved fishes are one solution for assessing historical change in fish trophic level

1. There are few resources available for assessing historical change in fish trophic dynamics, but specimens held in natural history collections could serve as this resource. In contemporary trophic ecology studies, trophic and source information can be obtained from compound‐specific stable isotope analysis of amino acids of nitrogen (CSIA‐AA‐N).
2. We subjected whole Sebastes ruberrimus and Clupea pallasii to formalin fixation and 70% ethanol preservation. We extracted tissue samples from each fish pre‐fixation, after each chemical change, and then in doubling time for 32–64 days once placed in the final preservative. All samples were subjected to CSIA‐AA‐N, and their glutamic acid and phenylalanine profiles and associated trophic position were examined for differences over time by species.
3. Glutamic acid and phenylalanine values were inconsistent in direction and magnitude, particularly during formalin fixation, but stabilized similarly (in 70% ethanol) among conspecifics. In some cases, the amino acid values of our final samples were significantly different than our initial pre‐preservation samples. Nonetheless, significant differences in glutamic acid, phenylalanine, and estimated trophic position were not detected among samples that were in 70% ethanol for >24 hr.
4. Our results suggest that the relative trophic position of fluid‐preserved specimens can be estimated using CSIA‐AA‐N, and CSIA‐AA‐N estimates for fluid‐preserved specimens should only be reported as relative differences. Timelines of trophic position change can be developed by comparing specimens collected at different points in time, revealing trophic information of the past and cryptic ecosystem responses.

     

6-MBOA affects testis size, but not delayed-type hypersensitivity, in white-footed mice (Peromyscus leucopus).

Many rodents use day length to time reproduction to occur when resources are abundant, but some species also use supplementary environmental cues. One supplementary cue is the plant-derived compound, 6-methoxy-2-benzoxazolinone (6-MBOA). Most rodents grow their gonads in response to 6-MBOA in their diets, but it is presently unknown whether they also use 6-MBOA to adjust other aspects of physiology, specifically their immune systems. 6-MBOA is structurally similar to melatonin, and seasonal changes in rodent immune activities are often mediated by melatonin. We therefore predicted that white-footed mice (Peromyscus leucopus), which breed seasonally and are reproductively sensitive to melatonin, would adjust their immune systems when fed 6-MBOA. 6-MBOA treated mice in long day lengths regressed their testes to a greater extent than mice fed a standard diet, or mice kept in short day lengths and fed 6-MBOA or a standard diet. One type of immune activity (delayed-type hypersensitivity) was not affected by 6-MBOA, however, although responses were greater in short versus long day mice. In sum, P. leucopus responded reproductively to 6-MBOA, although differently than other species; immune activity was unaffected. Other aspects of the immune system, especially in herbivorous rodents, may be affected by 6-MBOA and thus warrant further study.     

Peptides That Bind Specifically to an Antibody from a Chronic Lymphocytic Leukemia Clone Expressing Unmutated Immunoglobulin Variable Region Genes

Chronic lymphocytic leukemia (CLL) is a clonal disease of a subset of human B lymphocytes. Although the cause of the disease is unknown, its development and evolution appear to be promoted by signals delivered when B-cell receptors (BCRs) engage (auto)antigens. Here, using a peptide phage display library of enhanced size and diverse composition, we examined the binding specificity of a recombinant monoclonal antibody (mAb) constructed with the heavy chain and light chain variable domains of a CLL BCR that does not exhibit somatic mutations. As determined by testing the peptides identified in the selected peptide phage pool, this CLL-associated unmutated mAb bound a diverse set of sequences, some of which clustered in families based on amino acid sequence. Synthesis of these peptides and characterization of binding with the CLL-associated mAb revealed that mAb-peptide interactions were generally specific. Moreover, the mAb-peptide interactions were of lower affinities (micromolar K_D), as measured by surface plasmon resonance, than those observed with a CLL mAb containing somatic mutations (nanomolar K_D) and with immunoglobulin heavy chain variable (IGHV)-mutated antibodies selected by environmental antigens. This information may be of value in identifying and targeting B lymphocytes expressing specific BCRs in CLL patients and healthy subjects with monoclonal B lymphocytosis.     

The postembryonic transformation of the shell in emydine box turtles

A key trend in the 210‐million‐year‐old history of modern turtles was the evolution of shell kinesis, that is, shell movement during neck and limb retraction. Kinesis is hypothesized to enhance predator defense in small terrestrial and semiaquatic turtles and has evolved multiple times since the early Cretaceous. This complex phenotype is nonfunctional and far from fully differentiated following embryogenesis. Instead, kinesis develops slowly in juveniles, providing a unique opportunity to illustrate the postembryonic origins of an adaptive trait. To this end, we examined ventral shell (plastral) kinesis in emydine box turtles and found that hatchling plastron shape differs from that of akinetic‐shelled relatives, particularly where the hinge that enables kinesis differentiates. We also demonstrated shape changes relative to plastron size in juveniles, coinciding with a shift in the carapace‐plastron structural connection, rearrangement of ectodermal plates, and bone repatterning. Furthermore, because the shell grows larger relative to the head, complete concealment of the head and extremities is only achieved after relative shell proportions increase. Structural alterations that facilitate the box turtle's transformation are probably prepatterned in embryos but require function‐induced changes to differentiate in juveniles. This mode of delayed trait differentiation is essential to phenotypic diversification in turtles and perhaps other tetrapods.     

Extraction,Recovery, and Biostability of EDTA for Remediation of Heavy Metal-Contaminated Soil

Chelation removal of heavy metals from contaminated soil is seen as a viable remediation technique. A useful chelating agent should be strong, reusable, and biostable during metal extraction and recovery operations. This work tested the extraction, recovery, and biostability of EDTA as a potential remediating agent. Parameters, including EDTA concentration, soil type, soil content, washing cycle, precipitant concentration and type, and pH, were varied and tested during metal extraction and recovery operations. Factors, including EDTA concentration, aqueous and 5% soil slurry, presence of Pb, acclimated and unacclimated activated sludges, along with abiotic control, were varied and studied in the biodegradation of EDTA. The results showed that EDTA was able to extract lead completely from the tested soils, amenable to recovery by addition of cationic and anionic precipitants in the alkaline pH range, relatively biostable even under conditions very favorable toward biodegradation. Thus, EDTA is a strong, recoverable, and relatively biostable chelating agent that has potential for soil remediation application.     

Mitochondrial metabolism is a key regulator of the fibro-inflammatory and adipogenic stromal subpopulations in white adipose tissue

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Plasmid-encoded protein attenuates Escherichia coli swimming velocity and cell growth,not reprogrammed regulatory functions

In addition to engineering new pathways for synthesis, synthetic biologists rewire cells to carry out “programmable” functions, an example being the creation of wound-healing probiotics. Engineering regulatory circuits and synthetic machinery, however, can be deleterious to cell function, particularly if the “metabolic burden” is significant. Here, a synthetic regulatory circuit previously constructed to direct Escherichia coli to swim toward hydrogen peroxide, a signal of wound generation, was shown to work even with coexpression of antibiotic resistance genes and genes associated with lactose utilization. We found, however, that cotransformation with a second vector constitutively expressing GFP (as a marker) and additionally conferring resistance to kanamycin and tetracycline resulted in slower velocity (Δ~6 μm/s) and dramatically reduced growth rate (Δ > 50%). The additional vector did not, however, alter the run-and-tumble ratio or directional characteristics of H₂O₂–dependent motility. The main impact of this additional burden was limited to slowing cell velocity and growth, suggesting that reprogrammed cell motility by minimally altering native regulatory circuits can be maintained even when extraneous burden is placed on the host cell. © 2019 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2778, 2019.