Laboratory host range testing of Neomusotima conspurcatalis (Lepidoptera: Crambidae) – a potential biological control agent of the invasive weed,Old World climbing fern,Lygodium microphyllum (Lygodiaceae)

Old World climbing fern, Lygodium microphyllum, is a serious invasive weed in south Florida. Development of biological control is vital for sustainable management of L. microphyllum. Neomusotima conspurcatalis was discovered in Hong Kong in 1997 and was subsequently found causing feeding damage on L. microphyllum in much of its native range in Asia. Quarantine testing of N. conspurcatalis used 37 non-Lygodium fern species representative of New World genera of cultivated ferns and fern allies, one gymnosperm, three crop species, six Lygodium species, and the primary host L. microphyllum. No significant oviposition or feeding was observed on any of the 41 non-Lygodium species evaluated. Oviposition and feeding occurred on all Lygodium species, but amounts were low and usually significantly less than observed on L. microphyllum. The exception was L. japonicum, which was preferred as an oviposition host. Neomusotima conspurcatalis was only able to complete development on L. japonicum and L. palmatum, but survival on these species was only half that occurring on L. microphyllum. Neomusotima conspurcatalis is a Lygodium specialist. Lygodium japonicum is an invasive weed in the United States. Lygodium palmatum is restricted to areas of the United States where freezing winter temperatures would be lethal to N. conspurcatalis. It was concluded that N. conspurcatalis would pose no threat to native or cultivated plants in North America or the Caribbean and should be considered for biocontrol of L. microphyllum. A release petition was submitted in 2005. An USDA-APHIS release permit for N. conspurcatalis was issued in 2007.     

Interaction of a trypsin-like enzyme of Porphyromonas gingivalis W83 with antithrombin III

Abstract We have previously observed that trypsin-like activity in Porphyromonas gingivalis culture supernatants is inhibitable by the plasma arg-serpin antithrombin III (ATIII). This report demonstrates that a partially purified P. gingivalis trypsin-like enzyme ( M _r 47 000) is inhibited by ATIII with an association rate constant ( k _ass) of 5.65 × 10⁴ M⁻¹ s⁻¹ but does not form SDS-stable complexes. Heparin enhances the k _ass and stabilizes the complexes but in either case such inhibition is temporary and results in ATIII inactivation by reactive centre proteolysis between R³⁹³-S³⁹⁴. In the absence of heparin this is accompanied by N-terminal cleavage between K³⁹-I⁴⁰.     

The influence of ancymidol on morphology,anatomy, and chlorophyll levels in developing and mature Helianthus annuus leaves

Ancymidol foliar spray at 132 mg·liter^–1 a.i. modified leaf anatomy of developing Helianthus annuus L. Mammoth Russian leaves, but not of mature leaves. Ancymidol was effective in retarding plant growth when applied at the young seedling or at a more mature stage of growth. Ancymidol increased leaf weight per unit area and chlorophyll content on an area and unit weight basis, regardless of stage of leaf development. Total chlorophyll per leaf was also increased in mature leaves. Thus, darker green foliage due to increased chlorophyll content and modified leaf anatomy responses were determined to be independent effects.Texas Agricultural Experiment Station paper no. 22927.     

Competition between unrelated peptides recognized by H-2-Kd restricted T cells

P815 (H-2d) target cells incubated with synthetic peptides corresponding to region 170-182 of HLA or to region 141-161 of influenza nucleoprotein (NP) are lysed by DBA/2 derived cytolytic T cells (CTL) specific for HLA or by BALB/c derived CTL-specific for NP, respectively. Both peptide Ag are recognized in the context of Kd. We show herein that these unrelated, nonhomologous peptides clearly compete reciprocally for recognition by the appropriate Kd restricted CTL. In contrast, different NP peptides that are recognized by other CTL restricted by HLA-B37, H-2-Db or KK, either failed to compete or were much less efficient as competitors than NP peptides recognized in the context of Kd. The efficiency of a peptide as a competitor correlated with its potency as an Ag. The most efficient competitor was a variant peptide of NP 147-158 with R156 deleted, which had been previously shown to be 1,000 times more efficient as an Ag than its natural homolog. Our results suggest that peptides recognized by CTL in the context of the same MHC class I restriction element may bind to the same or interdependent site(s) on the restriction molecule.     

T cell-derived cytokines associated with pulmonary immune mechanisms in mice vaccinated with irradiated cercariae of Schistosoma mansoni.

In C57Bl/6 strain mice vaccinated with attenuated cercariae of Schistosoma mansoni, the major site of immune elimination of normal challenge parasites is the lungs. The immune effector mechanism involves formation of focal inflammatory responses; the abundance of CD4+ T cells and the activation of alveolar macrophages suggests a role for inflammatory cytokines. We report the profile of cytokines produced by cultures of leukocytes recovered by bronchoalveolar lavage (BAL) from the lungs of vaccinated and challenged mice. From 14 days after vaccination, BAL cultures contained infiltrating lymphocytes that produced abundant quantities of IFN-gamma and IL-3 on stimulation with larval Ag. Production declined from day 21 although the infiltrate of lymphocytes persisted. Challenge of vaccinated mice resulted in a second influx of IFN-gamma and IL-3-producing cells, earlier than after vaccination or in the appropriate controls. Ablation studies revealed that CD4+ T cells were essential for the production of IFN-gamma. The timing of cytokine production after vaccination, and challenge was coincident with the phases of macrophage activation previously reported. At no time could lymphocytes in BAL cultures be stimulated to proliferate with either larval Ag or mitogen, in contrast to splenocytes from the same mice. Furthermore, T cell growth factor activity was not detected in BAL cultures stimulated with Ag. We suggest that the lymphocytes recruited to the lungs are memory/effector cells. When Ag released from challenge schistosomula is presented to these cells, they respond by secreting cytokines that mediate the formation of cellular aggregates around the parasites, blocking their onward migration.     

Introgression of exotic Cervus (nippon and canadensis) into red deer (Cervus elaphus) populations in Scotland and the English Lake District

Since the mid‐19th century, multiple introductions of Japanese sika deer (Cervus nippon nippon) and North American wapiti (C. canadensis) have taken place in the British Isles. While wapiti have generally been unsuccessful, sika have been very successful, especially in Scotland where they now overlap at least 40% of the range of native red deer (C. elaphus). Hybridization between these two species and red deer has been demonstrated in captivity and in the wild. Using a panel of 22 microsatellite loci that are highly diagnostic between red deer and sika, and moderately diagnostic between red deer and wapiti, we investigated the extent of introgression between these species in 2,943 deer sampled from around Scotland and from the English Lake District using the Bayesian clustering software STRUCTURE. We also used a diagnostic mitochondrial marker for red deer and sika. Our survey extends previous studies indicating little introgression of wapiti nuclear alleles into red deer, in particular in Northern Scotland, Kintyre, and the Lake District. We found a new area of extensive sika introgression in South Kintyre. In the North Highlands, we show for the first time geographically scattered evidence of past hybridization followed by extensive backcrossing, including one red‐like individual with sika introgression, two sika‐like individuals with red deer introgression, and six individuals that were apparently pure sika at the nuclear markers assessed but which carried red deer mitochondria. However, there has not been a collapse of assortative mating in this region. Similarly, in the English Lake District red deer, we found only traces of past sika introgression. No sika alleles were detected in the Central Highlands or the Hebridean red deer refugia. We make suggestions for management to prevent further spread of sika alleles into red deer and vice versa.     

Host-range and cold temperature tolerance of Floracarus perrepae Knihinicki & Boczek (Acari: Eriophyidae), a potential biological-control agent of Lygodium microphyllum (Pteridophyta: Lygodiaceae)

Abstract The leaf galling eriophyid mite Floracarus perrepae is a widespread and damaging herbivore of Old World climbing fern, Lygodium microphyllum , across its native range in tropical and subtropical Asia and Australia; and was therefore selected as a candidate biological-control agent for the invasive fern in Florida, USA. The host testing of F. perrepae focused on Lygodium species from North America and the Neotropics, along with threatened or endangered ferns from Florida. Sporeling ferns were used for the initial no-choice screening and F. perrepae showed normal development on the Florida genotype of L. microphyllum with 33.0 ± 4.6 mites per marginal leaf roll gall, modest development on the North American native Lygodium palmatum with 29.0 ± 9.3 mites per roll, and minor development on six other fern species (4.0–0.3). Leaf rolls were induced only on Lygodium species and full rolls were common only on L. microphyllum . These same six non-target plant species were tested again as more mature plants in both no-choice and choice tests and F. perrepae developed only on L. microphyllum . Lethal minimum temperature and cold stress tests were also conducted on F. perrepae . These tests revealed that it would not likely establish north of USDA hardiness zone 8a (−9.5 to −12.2°C), which means it would not overlap with L. palmatum from temperate North America. Our studies conclude that F. perrepae is specific to L. microphyllum , poses little or no risk to native or cultivated ferns in North and South America, and therefore should be considered for release in Florida.     

Lifelong leukocyte telomere dynamics and survival in a free‐living mammal

Telomeres play a fundamental role in the maintenance of genomic integrity at a cellular level, and average leukocyte telomere length (LTL) has been proposed as a biomarker of organismal aging. However, studies tracking LTL across the entire life course of individuals are lacking. Here, we examined lifelong patterns of variation in LTL among four birth cohorts of female Soay sheep (Ovis aries) that were longitudinally monitored and sampled from birth to death. Over the first 4 months of life, there was within‐individual loss of LTL, consistent with findings in the human and primate literature, but there was little evidence of consistent LTL loss associated with age after this point. Overall, we observed only weak evidence of individual consistency in LTL across years and over the entire lifespan: Within‐individual variation was considerable, and birth cohorts differed markedly in their telomere dynamics. Despite the high levels of LTL variation within the lifetimes of individuals, there remained significant associations between LTL and longevity. Detailed analysis of the longitudinal data set showed that this association was driven by improved survival of individuals with longer LTL over the first 2 years of life. There was no evidence that LTL predicted survival in later adulthood. Our data provide the first evidence from a mammal that LTL can predict mortality and lifespan under natural conditions, and also highlight the potentially dynamic nature of LTL within the lifetimes of individuals experiencing a complex and highly variable environment.     

Cellular and humoral immunity in a wild mammal: Variation with age & sex and association with overwinter survival

Immune defenses are expected to be crucial for survival under the considerable parasite pressures experienced by wild animals. However, our understanding of the association between immunity and fitness in nature remains limited due to both the complexity of the vertebrate immune system and the often‐limited availability of immune reagents in nonmodel organisms. Here, we use methods and reagents developed by veterinary researchers for domestic ungulates on blood samples collected from a wild Soay sheep population, to evaluate an unusually broad panel of immune parameters. Our evaluation included different innate and acquired immune cell types as well as nematode parasite‐specific antibodies of different isotypes. We test how these markers correlate with one another, how they vary with age‐group and sex, and, crucially, whether they predict overwinter survival either within or among demographic groups. We found anticipated patterns of variation in markers with age, associated with immune development, and once these age trends were accounted for, correlations among our 11 immune markers were generally weak. We found that females had higher proportions of naïve T cells and gamma–delta T cells than males, independent of age, while our other markers did not differ between sexes. Only one of our 11 markers predicted overwinter survival: sheep with higher plasma levels of anti‐nematode IgG antibodies were significantly more likely to survive the subsequent high mortality winter, independent of age, sex, or weight. This supports a previous finding from this study system using a different set of samples and shows that circulating antibody levels against ecologically relevant parasites in natural systems represent an important parameter of immune function and may be under strong natural selection. Our data provide rare insights into patterns of variation among age‐ and sex groups in different T‐cell subsets and antibody levels in the wild, and suggest that certain types of immune response—notably those likely to be repeatable within individuals and linked to resistance to ecologically relevant parasites—may be most informative for research into the links between immunity and fitness under natural conditions.     

Simultaneous Use of Contrasting Fluorochromes to Separate Measles and Canine Distemper Viruses in a Common System

Measles and canine distemper viruses were grown together in a Vero monkey kidney cell line. Each virus could be identified and individually titrated by using the color contrast produced by the reddish tetra-methyl rhodamine isothiocyanate-tagged antimeasles conjugate and the green fluorescein isothiocyanate-tagged antidistemper conjugate. Both blue light and green light were used for the excitation of the fluorochromes. Incident light was transmitted to the specimen by a vertical illuminator of the Ploem type.