Global COVID-19 lockdown highlights humans as both threats and custodians of the environment

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus, initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness.

Environmental DNA from multiple pathogens is elevated near active Atlantic salmon farms

The spread of infection from reservoir host populations is a key mechanism for disease emergence and extinction risk and is a management concern for salmon aquaculture and fisheries. Using a quantitative environmental DNA methodology, we assessed pathogen environmental DNA in relation to salmon farms in coastal British Columbia, Canada, by testing for 39 species of salmon pathogens (viral, bacterial, and eukaryotic) in 134 marine environmental samples at 58 salmon farm sites (both active and inactive) over 3 years. Environmental DNA from 22 pathogen species was detected 496 times and species varied in their occurrence among years and sites, likely reflecting variation in environmental factors, other native host species, and strength of association with domesticated Atlantic salmon. Overall, we found that the probability of detecting pathogen environmental DNA (eDNA) was 2.72 (95% CI: 1.48, 5.02) times higher at active versus inactive salmon farm sites and 1.76 (95% CI: 1.28, 2.42) times higher per standard deviation increase in domesticated Atlantic salmon eDNA concentration at a site. If the distribution of pathogen eDNA accurately reflects the distribution of viable pathogens, our findings suggest that salmon farms serve as a potential reservoir for a number of infectious agents; thereby elevating the risk of exposure for wild salmon and other fish species that share the marine environment.

Collapse, Tipping Points, and Spatial Demographic Structure Arising from the Adopted Migrant Life History

The roles of dispersal and recruitment have long been a focal point in ecology and conservation. The adopted migrant hypothesis proposes a life history in which social learning transmits migratory knowledge between generations of iteroparous fish. Specifically, juveniles disperse from the parental spawning site, encounter and recruit to a local adult population, and learn migration routes between spawning and foraging habitats by following older, experienced fish. Although the adopted migrant life history may apply to many species of pelagic marine fishes, there is scant theoretical or empirical work on the consequent population dynamics. We developed and analyzed a mathematical model of this life history in which the recruitment of juveniles depends on the relative abundance of the local populations and recruitment overlap, which measures the ease with which juveniles are recruited by a nonparental population. We demonstrate that the adopted migrant life history can maintain spatial demographic structure among local populations, that it can also predispose local populations to collapse when a tipping point is crossed, and that recovery after collapse is impaired by reduced recruitment at small local population sizes.

Sea-louse parasites on juvenile wild salmon in the Broughton Archipelago, British Columbia, Canada

The global expansion of aquaculture has changed the structure of fish populations in coastal environments, with implications for disease dynamics. In Pacific Canada, farmed salmon act as reservoir hosts for parasites and pathogens, including sea lice (Lepeophtheirus salmonis and Caligus clemensi) that can transmit to migrating wild salmon. Assessing the impact of salmon farms on wild salmon requires regular monitoring of sea-louse infections on both farmed and wild fish. Since 2001, we have collected juvenile pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon annually at three sites in the Broughton Archipelago in British Columbia, Canada, during the annual juvenile salmon migration from fresh water to the open ocean. From sampled fish, we recorded counts of parasitic copepodid-, chalimus-, and motile-stage sea lice. We report louse abundances as well as supplementary observations of fish size, development, and health.

Application of Handheld Laser-Induced Breakdown Spectroscopy (LIBS) to Geochemical Analysis

While laser-induced breakdown spectroscopy (LIBS) has been in use for decades, only within the last two years has technology progressed to the point of enabling true handheld, self-contained instruments. Several instruments are now commercially available with a range of capabilities and features. In this paper, the SciAps Z-500 handheld LIBS instrument functionality and sub-systems are reviewed. Several assayed geochemical sample sets, including igneous rocks and soils, are investigated. Calibration data are presented for multiple elements of interest along with examples of elemental mapping in heterogeneous samples. Sample preparation and the data collection method from multiple locations and data analysis are discussed.

Rovibrational spectra of the N2–HF complex at the vHF=3 level

We report the analyses of the three intermolecular combination bands of the hydrogen-bonded N2-HF complex at vHF=3, observed by molecular beam intracavity laser induced fluorescence. The origin of the HF intermolecular bending combination band, (3001(1)0)<--(00000), is 11 548.45(3) cm(-1), 328.2 cm(-1) higher than that of the (30000)<--(00000) transition with an origin at 11 220.250(1) cm(-1). The average rotational constant of the (3001(1)0) level is 0.103 63(1) cm(-1), a 4.8% reduction from B(30000)=0.109 21(1) cm(-1). Perturbations are observed as line splittings, increased line widths, and reduced peak intensities of a number of lines of the e and f components of (3001(1)0). In addition, the centrifugal distortion coefficients of both components are large, negative, and different. The N2 intermolecular bend transition (30001(1))<--(00000) has an origin at 11 288.706(1) cm(-1), 68.456(2) cm(-1) above that of the (30000)<--(00000) transition. This is the lowest combination state at v(HF)=3 level. It is unperturbed, yielding B(30001(1))=0.110.10(1) cm(-1). The transition to the intermolecular stretching state, (30100)<--(00000), has an origin at 11 318.858(1) cm(-1) with B(30100)=0.105 84(1) cm(-1). Both the (30100) and (30000) levels show an isolated perturbation at J=4. The Lorentzian component of the line widths, which show considerable variation with soft mode, are GammaL(30000)=490(30) MHz, GammaL(30100)=630(30) MHz, GammaL(3001(1)0)=250(30) MHz, and GammaL(30001(1))=500(50) MHz.

Allozyme evidence for genetic autopolyploidy and high genetic diversity in tetraploid cranberry, Vaccinium oxycoccos (Ericaceae)

Polyploidy has been important in the evolution of angiosperms and may significantly affect population genetic diversity and structure. Nineteen isoenzyme loci were studied in diploid and tetraploid populations of Vaccinium oxycoccos (Ericaceae), and the results are compared with data previously reported for the related V. macrocarpon. Diploid V. oxycoccos and V. macrocarpon were readily discriminated based on their allozymic variation. No evidence for fixed heterozygosity was found in tetraploid V. oxycoccos. In contrast, all polymorphic loci exhibited both balanced and unbalanced heterozygotes, with some individuals exhibiting a pattern consistent with the presence of three alleles. These results support an autopolyploid origin for tetraploid V. oxycoccos. However, tetraploid V. oxycoccos possessed a suite of alleles not found in diploid V. oxycoccos; half of these alleles were shared with V. macrocarpon. This suggests that autotetraploid V. oxycoccos may have undergone hybridization with V. macrocarpon or that the autotetraploid retained the genetic variation present in an ancestral diploid species. Following theoretical expectations, proportion of polymorphic loci, mean number of alleles, and observed heterozygosity were significantly higher for the autotetraploid than for the diploid. Mean inbreeding (F(IS)) was similar for diploid and tetraploid V. oxycoccos. The latter exhibited population differentiation (F(ST)) exceeding both diploid species.

Aldose reductase and IGF-I gene expression in aortic and arteriolar smooth muscle during hypo- and hyperinsulinemic diabetes

Two genes whose expression is likely to be altered during diabetes mellitus are aldose reductase (AD) and insulin-like growth factor-I (IGF-I). We proposed that gene expression of AD is increased in vascular smooth muscle during diabetes mellitus due to hyperglycemia, while IGF-I expression is decreased in insulin-deficient diabetes and elevated in insulin-resistant diabetes. The mRNA for both was measured in the renal glomerulus, in the vascular smooth muscle of large arterioles from the brain, kidney, and small intestine, and in the aorta of hypoinsulinemic streptozotocin (STZ)-treated rats and hyperinsulinemic Zucker diabetic fatty (ZDF) rats. Quantitative in situ hybridization was used to determine variations in expression. Expression of the AD gene was unchanged in STZ and ZDF rats, except for a decrease of about 50% in glomeruli and renal smooth muscle of STZ diabetic rats. Expression of IGF-I generally decreased in vascular smooth muscle of insulin-depleted STZ diabetic rats, but was normal in hyperinsulinemic ZDF rats. The data indicate that decreased expression of the AD gene is a specific problem in renal vascular smooth muscle and glomeruli in the insulin-depleted STZ model of diabetes. The expression of the IGF-I gene in vascular muscle was decreased in hypoinsulinemic diabetic animals, but did not increase in hyperinsulinemic diabetic rats.

Reduced levels of histone H3 acetylation on the inactive X chromosome in human females

Novel antibodies were generated that are highly selective for either acetylated or unacetylated isoforms of histone H3, or the acetylated form of histone H4 in organisms as diverse as Tetrahymena and humans. Using these antibodies as pair-wise sets in immunocytological analyses, we demonstrate that the inactive X chromosome is hypoacetylated for both histone H3 and H4 in female mammalian cells, whereas the antibody that recognizes the unacetylated form of histone H3 identifies all chromosomes uniformly. These data verify and extend previous results and suggest that hypoacetylation of core histones may be a general feature of the chromatin along the inactive X chromosome.

Ultrastrucure of the superior oblique tendon

Individual collagen fibers in the superior oblique tendon of patients with superior oblique palsy studied at 60,000x with transmission electron microscopy are fewer in number and larger in diameter when compared to normal fibers. The relationship of these changes to function and to gross morphologic changes are not clear.

Postnatal maturation of rabbit renal collecting duct. II. Morphological observations

The renal collecting duct exhibits cellular heterogeneity. An ultrastructural analysis of this nephron segment during maturation has been performed to determine morphological characteristics of developing principal and intercalated cells (IC). Apical surface features and cytoplasmic ultrastructure were best revealed by scanning electron microscopy and by transmission electron microscopy, respectively. Morphological maturity was assessed by comparing measurements of apical perimeter, vesicular profiles, and mitochondrial volume percent. In mature cortical collecting duct (CCD), approximately 30% of total cells were rich in mitochondria and generally dark in matrix staining, i.e., IC. Most IC in outer cortex were microvillated, whereas in inner cortex most IC were microplicated with interspersed microvilli. Only approximately 16% of cells in outer medullary collecting duct (OMCD, outer stripe) were IC, with light cytoplasm and large protruding apical surfaces covered exclusively with microplicae. Neonatal CCDs showed no IC in outer cortex; a single type of principal-like cell was found in outer cortical region. Neonatal IC in both CCDs and OMCDs showed smaller apical perimeters, vesicular volumes, and mitochondrial volume percents than did mature IC. Whereas the number of cortical IC was reduced in the newborn, IC were present in mature numbers in OMCD and appeared relatively more mature than did IC of CCD. Some (approximately 10%) of IC in neonatal CCD did not show an identifiable apical surface pattern. Principal cells from both newborn CCD and OMCD were also morphometrically immature. It is clear that the neonatal collecting duct undergoes postnatal proliferation and differentiation.

Shock wave lithotripsy-induced renal injury

Both clinical and experimental reports clearly show that shock wave lithotripsy (SWL) causes acute renal effects in a majority, if not all, treated kidneys. SWL-induced acute renal damage may result in severe injury to the nephron, microvasculature, and the surrounding interstitium. In addition, at least three chronic adverse effects have been identified when shock waves are administered at a therapeutic dose. These include (1) an accelerated rise in arterial blood pressure, (2) a decrease in renal function, and (3) an increased rate of stone recurrence. The clinical and experimental data that document tissue injury as a result of shock wave treatment are compelling, but have not allowed us to determine the factors responsible for the adverse acute side effects or to identify conditions that may predispose a patient to serious long-term health problems. Thus, there is an urgent need for incisive, fundamental experimental studies to establish the safe limits for shock wave delivery. To accomplish this goal, animal experimentation is required so that the time course and severity of acute and chronic alterations can be followed in a model that closely mimics human renal structure and functions. The minipig provides this model.

The effects of convulsant doses of penicillin on primary afferents, dorsal root ganglion cells, and on 'presynaptic' inhibition in the spinal cord

Intracellular recordings were made from neurons in dorsal root ganglia (DRG) of rats, isolated in vitro. The depolarization of DRG cells caused by the application of gamma-aminobutyric acid (GABA) diminished reversibly when penicillin (0.08--2.0 mM) was added to the bathing fluid. The decrease of the input resistance of DRG cells measured during GABA perfusion was also depressed in the presence of penicillin, but no evidence of a shift of the reversal potential of the GABA-induced depolarization was found. Nor did penicillin (up to 10 mM) cause a change in the voltage-current function, in electrical excitability, in the inclination to repetitive firing, bursting discharge, or after discharge. In decapitate cat preparation the amplitude of the negative dorsal root potential (DRP or DR V) diminished by 0--50% after the i.v. administration of 0.5--1.0 X 10(6) I.U./kg (the convulsant dose) of penicillin. Post-tetanic depression of the DRP was aggravated by penicillin. The degree of depression of the DRP bore no relationship to the promptness of the eruption, and to the intensity, of the seizure activity induced by penicillin. The rates of rise and fall of the negative DRP (DR V) were consistently slowed, the positive DRP (DR VI) reduced, and the dorsal root reflex (DRR) blocked by penicillin. Inhibitory reflex effects presumed to be presynaptic were either enhanced or unchanged, never depressed by penicillin. This was seen when inhibitory function was gauged by monosynaptic reflex amplitude, and also from the inhibition of ventral root electrotonic excitatory postsynaptic potentials (VP EPSPs). Possible explanations of these seemingly paradoxical findings are discussed, with arguments in favor and against each.

LSD's effect on neuron populations in visual cortex gauged by transient responses of extracellular potassium evoked by optical stimuli

The effects of systemic LSD (10--25 micrograms/kg) on visually evoked [K+]o responses from the striate cortex have been investigated in cats. Elevation of [K+]o was dependent on the orientation, and direction of stimulus movement and showed ocular dominance. LSD most commonly produced a depression of [K+]o transients and a deterioration in their directional selectivity. These observations suggest that the effect of LSD is to produce a net depression in visually evoked neuronal firing.