The effect of temperature on catalytic function of glyceraldehyde-3-phosphate dehydrogenase from muscle of pig and carp Cyprinus carpio

1. The temperature dependence of the kinetics of glyceraldehyde-3-phosphate dehydrogenase from white muscle of carp and skeletal muscle of pig was examined. 2. The Km values of carp muscle enzyme were stable over the temperature range 5-35 degrees C, but increased for pig muscle enzyme with increasing temperature. 3. The Arrhenius plot for pig muscle enzyme is linear but non-linear for carp muscle enzyme. 4. The differences indicate that glyceraldehyde-3-phosphate dehydrogenase from white carp muscle may contribute to the adaptive mechanism of carp to varied temperature conditions.     

Population genetic structure of a California endemic branchiopod,Branchinecta sandiegonensis

Branchinecta sandiegonensis (Crustacea: Anostraca) is a narrow range endemic fairy shrimp discontinuously distributed in ephemeral pools on coastal mesas in San Diego County, USA. Ten populations across the range of the species were subjected to allozyme analysis for eleven loci. The species exhibits low variability (P₉₅ =9.1–45.5) and one third of the loci tested did not conform to Hardy-Weinberg equilibrium expectations. The species also exhibited a high degree of genetic differentiation between populations. F _ST values (fixation index) for most pairs of populations were above 0.25 (0.036–0.889).Low genetic variability and high genetic structure may result from low gene flow and founder effects due to habitat fragmentation and the lack of potential vectors for cyst dispersal. The unpredictable rainfall of the region also creates potential for variable population sizes which could affect structure and variability. This revised version was published online in August 2006 with corrections to the Cover Date.     

Characterization of the Palmitoylation Domain of SNAP-25

Abstract: SNAP-25 (synaptosomal associated protein of 25 kDa) is a neural specific protein that has been implicated in the synaptic vesicle docking and fusion process. It is tightly associated with membranes, and it is one of the major palmitoylated proteins found in neurons. The functional role of palmitoylation for SNAP-25 is unclear. In this report, we show that the palmitate of SNAP-25 is rapidly turned over in PC12 cells, with a half-life of ∼3 h, and the half-life for the protein is 8 h. Mutation of Cys to Ser at positions 85, 88, 90, and 92 reduced the palmitoylation to 9, 21, 42, and 35% of the wild-type protein, respectively. Additional mutations of either Cys^85,88 or Cys^90,92 nearly abolished palmitoylation of the protein. A similar effect on membrane binding for the mutant SNAP-25 was observed, which correlated with the degree of palmitoylation. These results suggest that all four Cys residues are involved in palmitoylation and that membrane association of SNAP-25 may be regulated through dynamic palmitoylation.     

Anencephaly in trisomy 18 associated with elevated alpha-1-fetoprotein in amniotic fluid

Summary Elevated levels of alpha-1-fetoprotein (AFP) were found in the amniotic fluid of a 36-year-old woman in the 15th week of gestation. Because of this and the results of repeated ultrasonography, abortion was induced. An anencephalic fetus with trisomy 18 was delivered. The possible correlation among neural-tube defects, chromosomal abnormalities, and level of AFP is discussed.     

Population-level impacts of natural and anthropogenic causes-of-death for Hawaiian monk seals in the main Hawaiian Islands

Identifying, assessing, and ranking the impact of individual threats is fundamental to the conservation and recovery of rare and endangered species. In this analysis, we quantify not only the frequency of specific causes-of-death (CODs) among Main Hawaiian Island (MHI) monk seals, but also assess the impact of individual CODs on the intrinsic growth rate, λ, of the MHI population. We used gross necropsy results, histopathology, and other evidence to assign probabilities of 11 COD types to each mortality and then used Monte Carlo sampling to evaluate the influence of each COD on λ. By right censoring realizations involving specific CODs, we were able to estimate λ (and its associated uncertainty) when CODs were selectively removed from influencing survival. Applying the analysis to all known and inferred deaths believed to have occurred 2004–2019, the CODs with the largest influence on λ were anthropogenic trauma, anthropogenic drowning, and protozoal disease. In aggregate, anthropogenic CODs had a larger effect on the growth rate than either natural or disease CODs. Possible bias associated with differential carcass detection, recovery, and COD classification are discussed.     

Characterization of Dinophysis spp. (Dinophyceae,Dinophysiales) from the mid-Atlantic region of the United States1

Due to the increasing prevalence of Dinophysis spp. and their toxins on every US coast in recent years, the need to identify and monitor for problematic Dinophysis populations has become apparent. Here, we present morphological analyses, using light and scanning electron microscopy, and rDNA sequence analysis, using a ~2-kb sequence of ribosomal ITS1, 5.8S, ITS2, and LSU DNA, of Dinophysis collected in mid-Atlantic estuarine and coastal waters from Virginia to New Jersey to better characterize local populations. In addition, we analyzed for diarrhetic shellfish poisoning (DSP) toxins in water and shellfish samples collected during blooms using liquid-chromatography tandem mass spectrometry and an in vitro protein phosphatase inhibition assay and compared this data to a toxin profile generated from a mid-Atlantic Dinophysis culture. Three distinct morphospecies were documented in mid-Atlantic surface waters: D. acuminata, D. norvegica, and a “small Dinophysis sp.” that was morphologically distinct based on multivariate analysis of morphometric data but was genetically consistent with D. acuminata. While mid-Atlantic D. acuminata could not be distinguished from the other species in the D. acuminata-complex (D. ovum from the Gulf of Mexico and D. sacculus from the western Mediterranean Sea) using the molecular markers chosen, it could be distinguished based on morphometrics. Okadaic acid, dinophysistoxin 1, and pectenotoxin 2 were found in filtered water and shellfish samples during Dinophysis blooms in the mid-Atlantic region, as well as in a locally isolated D. acuminata culture. However, DSP toxins exceeded regulatory guidance concentrations only a few times during the study period and only in noncommercial shellfish samples.     

Cardiomyopathy Mutations in the Tail of β-Cardiac Myosin Modify the Coiled-coil Structure and Affect Integration into Thick Filaments in Muscle Sarcomeres in Adult Cardiomyocytes

It is unclear why mutations in the filament-forming tail of myosin heavy chain (MHC) cause hypertrophic or dilated cardiomyopathy as these mutations should not directly affect contraction. To investigate this, we first investigated the impact of five hypertrophic cardiomyopathy-causing (N1327K, E1356K, R1382W, E1555K, and R1768K) and one dilated cardiomyopathy-causing (R1500W) tail mutations on their ability to incorporate into muscle sarcomeres in vivo. We used adenoviral delivery to express full-length wild type or mutant enhanced GFP-MHC in isolated adult cardiomyocytes. Three mutations (N1327K, E1356K, and E1555K) reduced enhanced GFP-MHC incorporation into muscle sarcomeres, whereas the remainder had no effect. No mutations significantly affected contraction. Fluorescence recovery after photobleaching showed that fluorescence recovery for the mutation that incorporated least well (N1327K) was significantly faster than that of WT with half-times of 25.1 ± 1.8 and 32.2 ± 2.5 min (mean ± S.E.), respectively. Next, we determined the effects of each mutation on the helical properties of wild type and seven mutant peptides (7, 11, or 15 heptads long) from the myosin tail by circular dichroism. R1382W and E1768K slightly increased the α-helical nature of peptides. The remaining mutations reduced α-helical content, with N1327K showing the greatest reduction. Only peptides containing residues 1301–1329 were highly α-helical suggesting that this region helps in initiation of coiled coil. These results suggest that small effects of mutations on helicity translate into a reduced ability to incorporate into sarcomeres, which may elicit compensatory hypertrophy.     

By Regulating Mitochondrial Ca2+-Uptake UCP2 Modulates Intracellular Ca2+

Introduction

The possible role of UCP2 in modulating mitochondrial Ca²⁺-uptake (mCa²⁺-uptake) via the mitochondrial calcium uniporter (MCU) is highly controversial.

Methods

Thus, we analyzed mCa²⁺-uptake in isolated cardiac mitochondria, MCU single-channel activity in cardiac mitoplasts, dual Ca²⁺-transients from mitochondrial ((Ca²⁺)m) and intracellular compartment ((Ca²⁺)c) in the whole-cell configuration in cardiomyocytes of wild-type (WT) and UCP2^-/- mice.

Results

Isolated mitochondria showed a Ru360 sensitive mCa²⁺-uptake, which was significantly decreased in UCP2^-/- (229.4±30.8 FU vs. 146.3±23.4 FU, P<0.05). Single-channel registrations confirmed a Ru360 sensitive voltage-gated Ca²⁺-channel in mitoplasts, i.e. mCa1, showing a reduced single-channel activity in UCP2^-/- (Po,total: 0.34±0.05% vs. 0.07±0.01%, P<0.05). In UCP2^-/- cardiomyocytes (Ca²⁺)m was decreased (0.050±0.009 FU vs. 0.021±0.005 FU, P<0.05) while (Ca²⁺)c was unchanged (0.032±0.002 FU vs. 0.028±0.004 FU, P>0.05) and transsarcolemmal Ca²⁺-influx was inhibited suggesting a possible compensatory mechanism. Additionally, we observed an inhibitory effect of ATP on mCa²⁺-uptake in WT mitoplasts and (Ca²⁺)m of cardiomyocytes leading to an increase of (Ca²⁺)c while no ATP dependent effect was observed in UCP2^-/-.

Conclusion

Our results indicate regulatory effects of UCP2 on mCa²⁺-uptake. Furthermore, we propose, that previously described inhibitory effects on MCU by ATP may be mediated via UCP2 resulting in changes of excitation contraction coupling.     

Influence of Manatees' Diving on Their Risk of Collision with Watercraft

Watercraft pose a threat to endangered Florida manatees (Trichechus manatus latirostris). Mortality from watercraft collisions has adversely impacted the manatee population’s growth rate, therefore reducing this threat is an important management goal. To assess factors that contribute to the risk of watercraft strikes to manatees, we studied the diving behavior of nine manatees carrying GPS tags and time–depth recorders in Tampa Bay, Florida, during winters 2002–2006. We applied a Bayesian formulation of generalized linear mixed models to depth data to model the probability (P_t) that manatees would be no deeper than 1.25 m from the water’s surface as a function of behavioral and habitat covariates. Manatees above this threshold were considered to be within striking depth of a watercraft. Seventy-eight percent of depth records (individual range 62–86%) were within striking depth (mean = 1.09 m, max = 16.20 m), illustrating how vulnerable manatees are to strikes. In some circumstances manatees made consecutive dives to the bottom while traveling, even in areas >14 m, possibly to conserve energy. This is the first documentation of potential cost-efficient diving behavior in manatees. Manatees were at higher risk of being within striking depth in shallow water (<0.91 m), over seagrass, at night, and while stationary or moving slowly; they were less likely to be within striking depth when ≤50 m from a charted waterway. In shallow water the probability of a manatee being within striking depth was 0.96 (CI = 0.93–0.98) and decreased as water depth increased. The probability was greater over seagrass (P_t = 0.96, CI = 0.93–0.98) than over other substrates (P_t = 0.73, CI = 0.58–0.84). Quantitative approaches to assessing risk can improve the effectiveness of manatee conservation measures by helping identify areas for protection.     

A curated gene list for expanding the horizons of pigmentation biology

Over the past century, studies of human pigmentary disorders along with mouse and zebrafish models have shed light on the many cellular functions associated with visible pigment phenotypes. This has led to numerous genes annotated with the ontology term “pigmentation” in independent human, mouse, and zebrafish databases. Comparisons among these datasets revealed that each is individually incomplete in documenting all genes involved in integument‐based pigmentation phenotypes. Additionally, each database contained inherent species‐specific biases in data annotation, and the term “pigmentation” did not solely reflect integument pigmentation phenotypes. This review presents a comprehensive, cross‐species list of 650 genes involved in pigmentation phenotypes that was compiled with extensive manual curation of genes annotated in OMIM, MGI, ZFIN, and GO. The resulting cross‐species list of genes both intrinsic and extrinsic to integument pigment cells provides a valuable tool that can be used to expand our knowledge of complex, pigmentation‐associated pathways.