Habitat preference in the critically endangered yellow‐tailed woolly monkey (Lagothrix flavicauda) at La Esperanza,Peru

Habitat loss is one of the main threats to wildlife. Therefore, knowledge of habitat use and preference is essential for the design of conservation strategies and identification of priority sites for the protection of endangered species. The yellow‐tailed woolly monkey (Lagothrix flavicauda Humboldt, 1812), categorized as Critically Endangered on the IUCN Red List, is endemic to montane forests in northern Peru where its habitat is greatly threatened. We assessed how habitat use and preference in L. flavicauda are linked to forest structure and composition. The study took place near La Esperanza, in the Amazonas region, Peru. Our objective was to identify characteristics of habitat most utilized by L. flavicauda to provide information that will be useful for the selection of priority sites for conservation measures. Using presence records collected from May 2013 to February 2014 for one group of L. flavicauda, we classified the study site into three different use zones: low‐use, medium‐use, and high‐use. We assessed forest structure and composition for all use zones using 0.1 ha Gentry vegetation transects. Results show high levels of variation in plant species composition across the three use zones. Plants used as food resources had considerably greater density, dominance, and ecological importance in high‐use zones. High‐use zones presented similar structure to medium‐ and low‐use zones; thus it remains difficult to assess the influence of forest structure on habitat preference. We recommend focusing conservation efforts on areas with a similar floristic composition to the high‐use zones recorded in this study and suggest utilizing key alimentation species for reforestation efforts.     

Kinetic studies on the inactivation of 5-lipoxygenase by 5(S)-hydroperoxyeicosatetraenoic acid

The oxygenation of arachidonic acid (AA) by guinea-pig neutrophil 5-lipoxygenase terminates prematurely at a substrate utilization of only 50%. In the presence of dithiothreitol (DTT), reaction progress continues longer but still terminates prematurely, at about 70% substrate turnover. The addition of more substrate during the first 60 seconds of the initial reaction resulted in continued product formation. However, at times after 120 seconds, the addition of more AA could not produce additional product formation. Together, these results indicate a time-dependent (t1/2 = 0.5-1.0 min), irreversible loss of enzyme activity. To determine if the product 5-hydroperoxy-6,8,11,14-eicosatetraenoic acid (5-HPETE) mediates the inactivation, it was tested for its ability to irreversibly inhibit the enzyme and found to inactivate 5-lipoxygenase with Ki = 0.05 +/- 0.01 microM and ki = 1.4 +/- 0.4 min-1. DTT changed the apparent affinity of 5-HPETE (Ki = 0.33 +/- 0.09 microM) but had no effect on the rate of inactivation (ki = 1.26 +/- 0.62 min-1). In contrast, the hydroxy derivative of 5-HPETE, 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), is a reversible, time-independent inhibitor with Ki = 6.3 +/- 0.9 microM regardless of DTT. The ability of thiols to protect 5-lipoxygenase from production inactivation is due, at least in part, to a non-enzymatic reaction between DTT and 5-HPETE that converts the hydroperoxy acid to a material that can no longer inactivate the enzyme.     

Discriminative effect of gamma-glutamyl transpeptidase inhibitors on metabolism of leukotriene C4 in peritoneal cells

Leukotrienes are naturally-occurring metabolites of arachidonic acid that are formed via the 5-lipoxygenase pathway in several tissues. Rat peritoneal cells (RPC) can produce leukotrienes C4, D4 and E4 (LTC4, LTD4 and LTE4) in response to stimulation with the calcium ionophore A23187 (1,2). The mechanism of enzymatic conversion of LTC4 to LTD4 is presumed to be via the action of gamma-glutamyl transpeptidase (gamma-GTPase, Figure 1) and has been demonstrated with purified enzymes from rat and porcine kidneys (3-6). We report that RPC contain gamma-GTPase-like activity that catalyzes the liberation of p-Nitroaniline (p-NA) from the chromophoric substrate gamma-glutamyl-p-nitroanilide (gamma-GpNA) in the presence of the acceptor molecules glycylglycine and L-cysteine. Furthermore, we demonstrate that under similar conditions, this preparation catalyzes the conversion of LTC4 to LTD4. Activity with gamma-GpNA is inhibited by D,L-gamma-glutamyl(o-carboxy)-phenylhydrazide (GOP) and serine-borate complex, (competitive inhibitors of kidney gamma-GTPase), and 6-diazo-5-oxo-L-norleucine (DON) and o-diazo-acetyl-L-serine (AZA), (irreversible inhibitors of kidney gamma-GTPase). In contrast, conversion of both endogenously-generated or exogenous LTC4 into LTD4 by RPC is inhibited only by serine-borate complex. These results suggest that RPC contain at least two distinct forms of gamma-GTPase; one capable of recognizing gamma-GpNA and susceptible to inhibition by all four compounds, and a second form utilizing also LTC4 as substrate, and is not inhibited by high concentrations of several "classic" gamma-GTPase inhibitors.     

Recovery of the simian immunodeficiency virus (SIV) and depression of colony formation in in vitro infected progenitor cell-enriched rhesus bone marrow (BM)

Rhesus progenitor-enriched BM was exposed overnight to SIV and cultured in a limiting dilution assay where the potential for progenitor interaction with lymphocytes or macrophages was low. Virus was consistently isolated late in culture, detection being aided by coculture with CEM₁₇₄ lymphoblasts. Although infected cells had reduced clonogenic activity, colonies were indistinguishable from those derived from uninfected BM with respect to proliferative potential, morphology, and longevity in culture. Primate immunodeficiency viruses, therefore, may infect immature BM populations, directly affecting hematopoietic activity.     

Potent constriction of cat coronary arteries by hydroperoxides of arachidonic acid and its blockade by anti-inflammatory agents

The omega-6 and omega-9 hydroperoxides of arachidonic acid caused dose-dependent constriction of cat coronary arteries in concentrations of 10(-8) to 10(-5) M. Their potency was comparable to that of prostaglandin (PG) E2, and PGF2 alpha and 100 times greater than that of arachidonic acid. The cyclooxygenase inhibitor, meclofenamate markedly reduced constriction caused by the hydroperoxides but potentiated constriction caused by the prostaglandins. The effects of the hydroperoxides were also reduced by indomethacin and dexamethasone but were unaffected by the thromboxane synthetase inhibitor imidazole. Since the hydroperoxides are not substrates for cyclooxygenase, it is suggested that they have a direct effect on the arteries which can be antagonized by anti-inflammatory drugs.     

PFIESTERIA PISCICIDA GEN. ET SP. NOV. (PFIESTERIACEAE FAM. NOV.), A NEW TOXIC DINOFLAGELLATE WITH A COMPLEX LIFE CYCLE AND BEHAVIOR1

The newly described toxic dinoflagellate Pfiesteria piscicida is a polymorphic and multiphasic species with flagellated, amoeboid, and cyst stages. The species is structurally a heterotroph; however, the flagellated stages can have cleptochloroplasts in large food vacuoles and can temporarily function as mixotrophs. The flagellated stage has a typical mesokaryotic nucleus, and the theca is composed of four membranes, two of which are vesicular and contain thin plates arranged in a Kofoidian series of Po, cp, X, 4′, 1a, 5″, 6c, 4s, 5″′, and 2″″. The plate tabulation is unlike that of any other armored dinoflagellate. Nodules often demark the suture lines underneath the outer membrane, but fixation protocols can influence the detection of plates. Amoeboid benthic stages can be filose to lobose, are thecate, and have a reticulate or spiculate appearance. Amoeboid stages have a eukaryotic nuclear profile and are phagocytic. Cyst stages include a small spherical stage with a honeycomb, reticulate surface and possibly another stage that is elongate and oval to spherical with chrysophyte-like scales that can have long bracts. The species is placed in a new family, Pfiesteriaceae, and the order Dinamoebales is emended.     

Conversion of oat (<Emphasis Type="Italic">Avena sativa</Emphasis> L.) haploid embryos into plants in relation to embryo developmental stage and regeneration media

Obtaining oat DH lines is only effective via wide crossing with maize. Seven hundred haploid embryos from 21 single F₁ progeny obtained from wide crosses with maize were isolated, divided into four groups according to their size (<0.5 mm, 0.5–0.9 mm, 1.0–1.4 mm, and ≥1.5 mm), and transferred into 190–2 regeneration medium with different growth regulators: 0.5 mg L^?1 kinetin (KIN) and 0.5 mg L^?1 1-naphthaleneacetic acid (NAA); 1 mg L^?1 zeatin (ZEA) and 0.5 mg L^?1 NAA; or 1 mg L^?1 dicamba (DIC), 1 mg L^?1 picloram (PIC), and 0.5 mg L^?1 kinetin (KIN). Among all isolated embryos, approximately 46.1% were between 1.0–1.4 mm, while the smallest group of embryos (7.1%) were those <0.5 mm. The ability of haploid embryos to germinate varied depending on oat genotypes and the size of embryos. Haploid embryos <0.5 mm were globular and did not germinate, whereas embryos ≥1.5 mm had clearly visible coleoptiles, radicles, and scutella, and were able to germinate. Germination of oat haploid embryos varied depending on growth regulators in the regeneration medium. Most haploid embryos germinated on medium with 0.5 mg L^?1 NAA and 0.5 mg L^?1 KIN, while the fewest germinated on medium with 1 mg L^?1 DIC, 1 mg L^?1 PIC, and 0.5 mg L^?1 KIN. One hundred thirty germinated haploid embryos converted into haploid plants. Fifty oat DH lines were obtained after colchicine treatment.     

Glutathione S-transferase M1 genotype influences sister chromatid exchange induction but not adaptive response in human lymphocytes treated with 1,2-epoxy-3-butene

Induction of sister chromatid exchanges (SCEs) by 1,2-epoxy-3-butene (monoepoxybutene, MEB), an epoxide metabolite of 1,3-butadiene, in human whole-blood lymphocyte cultures has previously been observed to depend on the glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) genotype of the blood donor. Pretreatment of lymphocyte cultures with a low dose of MEB has been shown to reduce the SCE response obtained by later treatment with a higher concentration of MEB. To investigate whether this adaptive response depends on the GSTM1 genotype of the donor, SCE induction by MEB (25 and 250 microM at 48 h for 24 h) was studied from whole-blood lymphocyte cultures of young non-smoking male and female subjects representing GSTM1 positive (n=7) and null (n=7) genotypes, with or without a MEB pretreatment (12.5 microM at 24 h). A higher mean number of induced SCEs per cell at 250 microM MEB was observed in lymphocytes of the GSTM1 null than positive donors, a statistically significant difference being obtained in the presence of the adaptive treatment (9.44 vs. 6.56; results from ethanol-treated controls subtracted). The pretreatment resulted in a statistically significant reduction in the response of the GSTM1 null group at both concentrations of MEB and in the GSTM1 positive group at 250 microM. However, there were no statistically significant differences in the adaptive response of the two genotypes. In conclusion, the present study further supported earlier findings on an increased sensitivity of GSTM1 null donors to SCE induction by MEB, suggesting that GSTM1 is involved in the detoxification of MEB in human lymphocyte cultures. As an adaptive response was observed in both GSTM1 positive and null donors, the phenomenon cannot be explained by GSTM1 induction. It may represent induction of other enzymes operating in MEB detoxification, or activation of DNA repair.     

Pathogenesis of acute ulceration response (AUR) in hybrid striped bass

In a previous study, we discovered that acute confinement stress causes rapid ulceration of the fins of hybrid striped bass Morone saxatilis female x M. chrysops male (Noga et al. 1998. Vet Pathol 35:102-107). In this paper, we report the development of a reproducible model for studying this phenomenon in juvenile hybrid striped bass. We also determined how quickly ulceration could develop in acutely stressed fish and documented the sequential light microscopic and ultrastructural changes associated with this response. When hybrid striped bass were subjected to a standardized confinement protocol, the pathological response was extremely rapid (fin ulceration began to develop within 15 min of confinement). Grossly, the distal edges of the fins became blanched, and melanophores aggregated near the basement membrane and dermis after 15 min of confinement. Microscopically, the earliest detectable change in the fins, which occurred within 15 min of confinement, was swelling and loss of microridges of the outermost epidermal cells; this was followed by epidermal erosion. After 30 min of stress, epidermal ulceration developed at the distal edges of the fins. At this time, both necrotic and apoptotic epidermal cells were present. The middle and basal epidermal layers were severely spongiotic and the dermis and hypodermis were edematous. Over longer periods (up to 2 h), lesions were similar but increasingly more severe, progressing from the distal edge of the fin towards the base. The response to acute stress showed a significant correlation between confinement period and severity of the pathological changes (epidermal degeneration, epidermal ulceration and leukocyte infiltration). Also, we demonstrated that epidermal damage was not restricted to the fins but also affected the body skin and eyes. The ventral area of the body and the corneal epithelium of stressed fish were ulcerated; however, skin on the head and operculum was not affected, suggesting a site-specific mode of damage. In stressed fish, epidermal ulceration was found in 67 to 97% of all fins, 88% of skin on the ventrum, and 67% of corneas, while control fish had only very mild epidermal ulceration in the few fish in which it was present (on 5 to 10% of the fins, but not on the ventral skin or corneas). Due to the widespread damage to epidermal tissues of the body surface, we have named this the acute ulceration response (AUR). Our study indicates that acute confinement can rapidly cause significant damage to epidermal and ocular epithelium. AUR might be a primary cause of morbidity in acutely stressed fish.