Plant phylogeny determines host selection and acceptance of the oligophagous leaf beetle Cassida rubiginosa

BACKGROUND

Predicting the host range of biocontrol agents is important for the safe and effective implementation of biocontrol of weeds. In this study, we examined the phylogenetic pattern of host selection and acceptance by the biocontrol beetle, Cassida rubiginosa. The beetle was released in New Zealand for control of Cirsium arvense, its primary host plant, but has potential to attack many Cardueae (thistles and knapweeds) species. We conducted a series of no-choice and choice experiments and modelled the responses of Cassida rubiginosa in relation to phylogenetic distance from Cirsium arvense.

RESULTS

The olfactory recognition (single odour) and preference (two odours) of the beetle showed a significant phylogenetic relationship. These relationships showed a high degree of correlation with 66.9% of the variation in olfactory recognition and 82.8% of the variation in olfactory preference explained by phylogeny. Where the beetle could contact plants, under no-choice conditions there was no phylogenetic pattern to host plant acceptance. However, under choice conditions, phylogenetic distance was a strong predictor of feeding and oviposition preference. These relationships showed a high degree of correlation, with 63.4% of the variation in feeding preference, and 89.0% of the variation in oviposition preference, explained by phylogeny.

CONCLUSIONS

As far as we are aware, this is the first demonstration of an herbivorous insect that exhibits a phylogenetic pattern to olfactory host plant selection. Host plant utilisation by Cassida rubiginosa in New Zealand will be mostly restricted to Cirsium and Carduus species, with minimal potential for impact on other Cardueae weeds. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Snail meat consumption in Buea-Cameroon: exposures to foodborne pathogens through social practices assessed in 2019 and 2021

BACKGROUND

Snail meat is an important source of nutrition in Cameroon, but the food safety risks are poorly understood. We characterized public health risks from snail meat consumption as a social system in Cameroon, by examining local snail practices that expose snail meat handlers and consumers to foodborne pathogens.

METHODS

We used exploratory qualitative approaches, that is, lived experience, face-to-face in-depth interviews, participant observation and a focus group, to explore fifteen key informants' routines and lived experiences, and perceptions of two health officials on the food safety practices around snail meat consumption in Cameroon. This information was organized and interpreted using Soft Systems Methodology and Social Practice Theory, which permitted a systemic appreciation of local practices.

RESULTS

We distinguished five kinds of actors (snail vendors, market sellers, street vendors, street eaters and home consumers), who performed seven successive practices (picking, selling, cracking, washing, cooking, hawking and eating). We then identified three worldviews about snails: family support or to reduce poverty, a source of nutrition and a food choice (taste, preference). Our findings revealed participants' competences were based on childhood learning and 'inborn' experiences, and materials used in snail activities reflected participants' parentage and 'state of poverty'. Although most interviewees highlighted 'unhygienic conditions' when explaining snail picking locations, participants believed washing and cooking should kill all contaminants.

CONCLUSION

Several opportunities for human exposures to foodborne pathogens including snail picking in domestic wastes and sewage, the selling of unpackaged live snails, improper snail meat washing and hawking in loosely closed buckets, were apparent from our analysis. These findings suggest fruitful opportunities aimed at improving health outcomes among African snail meat handlers and consumers.

The benefits of contributing to the citizen science platform iNaturalist as an identifier

As the number of observations submitted to the citizen science platform iNaturalist continues to grow, it is increasingly important that these observations can be identified to the finest taxonomic level, maximizing their value for biodiversity research. Here, we explore the benefits of acting as an identifier on iNaturalist.

Public Health Risk of Foodborne Pathogens in Edible African Land Snails, Cameroon

In tropical countries, land snails are an important food source; however, foodborne disease risks are poorly quantified. We detected Campylobacter spp., Yersinia spp., Listeria spp., Salmonella spp., or Shiga-toxigenic Escherichia coli in 57%-86% of snails in Cameroon. Snail meat is a likely vector for enteric diseases in sub-Saharan Africa countries.

A taxonomically detailed and large-scale view of the factors affecting the distribution and abundance of tree species planted in private gardens of Christchurch city, New Zealand

A city’s planted trees, the great majority of which are in private gardens, play a fundamental role in shaping a city’s wild ecology, ecosystem functioning, and ecosystem services. However, studying tree diversity across a city’s many thousands of separate private gardens is logistically challenging. After the disastrous 2010–2011 earthquakes in Christchurch, New Zealand, over 7,000 homes were abandoned and a botanical survey of these gardens was contracted by the Government’s Canterbury Earthquake Recovery Authority (CERA) prior to buildings being demolished. This unprecedented access to private gardens across the 443.9 hectares ‘Residential Red Zone’ area of eastern Christchurch is a unique opportunity to explore the composition of trees in private gardens across a large area of a New Zealand city. We analysed these survey data to describe the effects of housing age, socio-economics, human population density, and general soil quality, on tree abundance, species richness, and the proportion of indigenous and exotic species. We found that while most of the tree species were exotic, about half of the individual trees were local native species. There is an increasing realisation of the native tree species values among Christchurch citizens and gardens in more recent areas of housing had a higher proportion of smaller/younger native trees. However, the same sites had proportionately more exotic trees, by species and individuals, amongst their larger planted trees than older areas of housing. The majority of the species, and individuals, of the larger (≥10 cm DBH) trees planted in gardens still tend to be exotic species. In newer suburbs, gardens in wealthy areas had more native trees than gardens from poorer areas, while in older suburbs, poorer areas had more native big trees than wealthy areas. In combination, these describe, in detail unparalleled for at least in New Zealand, how the tree infrastructure of the city varies in space and time. This lays the groundwork for better understanding of how wildlife distribution and abundance, wild plant regeneration, and ecosystem services, are affected by the city’s trees.

Density-dependent shoot-borer herbivory increases the age of first reproduction and mortality of neotropical tree saplings

Shoot herbivory by the sapling specialist shoot-borer Cromarcha stroudagnesia (Lepidoptera, Pyralidae, Chrysauginae) is shown to have large direct and indirect effects on the rates of height increment and mortality of saplings of its host tree, Tabebuia ochracea (Bignoniaceae), in the secondary successional tropical dry forests of the Area de Conservación Guanacaste, Costa Rica. Experiments and field observations over 3-4 years show a substantial reduction in sapling height increments due to C. stroudagnesia herbivory, of equivalent magnitude to the difference in height increments between undamaged saplings in canopy gaps and full understorey shade. Extrapolating this data at average amounts of C. stroudagnesia herbivory increases the duration of the pre-reproductive sapling life stage by about 40% relative to undamaged plants. This is an underestimate, as top shoot herbivory by C. stroudagnesia also increased the probability of canopy gap saplings being overtopped and shaded by surrounding vegetation. Sapling mortality was increased by C. stroudagnesia herbivory, with 11.8% of the most heavily damaged young saplings dying in 3 years while no undamaged saplings died. Cromarcha stroudagnesia herbivory strongly increases with the number of conspecific T. ochracea saplings and the number of conspecific shoots within 50 m of focal saplings. It is therefore likely to disproportionately decrease the number of saplings and rate of recruitment to reproductive age in areas of high conspecific sapling density. These results suggest that sapling herbivory, especially herbivory of terminal meristems, has an important but largely unexplored influence on the population dynamics of tropical tree species. They further demonstrate that sapling herbivory by insects, in addition to the well-studied insect predation and herbivory of seedlings, is likely to influence tree species coexistence in tropical forests.

Keratoacanthoma with perineural invasion: a report of 40 cases

Keratoacanthoma is a unique clinicopathological entity, despite a recent trend to regard it as a variant of squamous cell carcinoma. The occurrence of perineural invasion is an uncommon phenomenon in keratoacanthomas, with a predilection for lesions on the face. We studied a series of 40 cases of keratoacanthoma in which perineural invasion occurred. Of the 40 cases, 27 were from the head or neck region. We found no metastasis or direct death attributable to the presence of perineural invasion in the 35 cases in our series for whom follow-up data were available. In only one case did local recurrence occur and this was not considered by the authors to be directly attributable to the presence of perineural invasion. These findings add further support to the notion that keratoacanthoma is biologically different from squamous cell carcinoma.

Evaluation and validation of a commercial ELISA for diazinon in surface waters

The performance of a commercially available microtiter plate ELISA kit for the determination of diazinon was evaluated for sensitivity, selectivity, intra-assay repeatability, accuracy, and matrix effects in fortified distilled water and filtered and unfiltered environmental surface water samples. Repeatability and reproducibility studies show that the kit satisfies current EPA criteria for the assessment of analytical methods. Mean recoveries from spiked samples averaged 80.3, 95.5, and 103.5% from distilled, unfiltered surface, and filtered surface waters, respectively. The experimentally determined method detection limit (MDL) for the commercial diazinon microtiter plate format (0.0159 microg L(-)(1)) was comparable to the least detectable dose (LDD) established by the manufacturer (0.022 microg L(-)(1)). Specificity studies indicate that the diazinon polyclonal antibody can readily distinguish the target compound from other structurally similar organophosphorus analogues, with the exception of diazoxon. Cross-reactivity with the oxon was approximately 29%, while reactivity with pirimiphos-methyl, pirimiphos-ethyl, and chlorpyrifos-ethyl was negligible. A slight matrix effect was discovered to be present in both filtered and unfiltered environmental water matrixes, but its effect on the immunoassays is insignificant within experimental error. For validation of the microtiter plate ELISA format, environmental surface and storm runoff water samples were collected, split, and analyzed directly by ELISA and by liquid-liquid extraction followed by GC (California State Department of Food and Agriculture method EM 46.0). Results of the two analytical methods were then compared statistically. A close correlation was found between methods for unspiked and untreated river water samples (r = 0.969) while a much less robust correlation was obtained for runoff waters (r = 0.728). Results from runoff waters exhibit a particularly high positive bias for the ELISA method relative to the GC method. Cross-reactivity of diazoxon and probably other unidentified cross-reacting components may be responsible for the exaggerated account of the target analyte in surface and runoff waters. While excellent for screening purposes, further study is required to elucidate and quantify the factors responsible for the consistent overestimation of ELISA results before the kit can be employed routinely for regulatory compliance monitoring.

Promoter interference in a bacteriophage lambda control region: effects of a range of interpromoter distances

The p(R) and p(RM) promoters of bacteriophage lambda direct transcription in divergent directions from start sites separated by 83 phosphodiester bonds. We had previously shown that the presence of an RNA polymerase at p(R) interfered with open complex formation at p(RM) and that this effect was alleviated by the deletion of 10 bp between the two promoters. Here we present a detailed characterization of the dependence of the interference on the interpromoter distance. It was found that the reduced interference between the two promoters is unique to the 10-bp deletion. The relief of interference was demonstrated to be due to the facilitation of a step subsequent to RNA polymerase binding to the p(RM) promoter. A model to explain these observations is proposed. A search of known Escherichia coli promoters identified three pairs of divergent promoters with similar separations to those investigated here.

The human uniqueness of HIV: innate immunity and the viral Tat protein

We have previously reported, and confirm here, that the human innate system of natural antibodies includes two, each of which is reactive, presumably by happenstance, with a specific sequence of HIV Tat protein. Comparison of cohorts of HIV+ and normal (HIV-) sera indicate that, following a period of post-infection latency, the titers of those natural antibodies decline and other Tat reactive antibodies, as evidence of induced immune response, do not arise. That human-typical pattern of innate/adaptive reactivity with HIV Tat protein is shared by chimpanzees, but not by other mammals tested in this study, in which those natural antibodies are not present, and apparently induced Tat-reactive antibodies do arise. Evidence of a temporal relationship between the decline of the Tat reactive natural antibodies and progression of HIV pathogenesis, including demise of CD4+T cells, suggests a role for those antibodies in retardation of that pathoprogression. However, that providential arrest of Tat-related pathogenicity may be limited by the immune system recognition of the natural antibody-reactive sequences of Tat as "self" with consequent induction of tolerance and restriction of production of those antibodies. The limited occurrence of progression to AIDS in chimpanzees may reflect an additional innate characteristic, one of resistance to tolerance-based diminishment of the protective natural antibodies. Although not yet defined, that characteristic may be shared by the occasionally observed HIV+ humans known as LTNP (longterm-non-progressors).

Two human neonatal IgM antibodies encoded by different variable-region genes bind the same linear peptide: evidence for a stereotyped repertoire of epitope recognition

Two monoclonal IgM Abs have been produced from lymphocytes isolated from two human umbilical cord bloods. These mAbs recognize a conformational epitope present in a CNBr digestion fraction of lactoferrin. Linear epitopes recognized by each mAb were selected from several phage display peptide libraries. In each case, phages displaying a peptide with a motif defined by [WF],G,[EQS],N were recovered. Phages displaying that motif bound equally well to either mAb but did not bind to control IgM. A peptide bearing this motif competed with the phage-displayed peptides for binding to either mAb. The same peptide also competes with a component of the CNBr digestion fraction of lactoferrin for Ab binding in ELISA. The Abs use different families of VH, JH, and VK gene cassettes but use the same JK cassette. All segments are virtually identical to their germline gene counterparts. This work provides further evidence that certain innate specificities are stereotyped among individuals.

Promoter recognition by Escherichia coli RNA polymerase: effects of the UP element on open complex formation and promoter clearance

Escherichia coli promoters for transcription of ribosomal and tRNAs are greatly activated by an A+T-rich "UP" element upstream of the -35 region. These same promoters have also been found to otherwise deviate in several respects from the consensus promoter sequence. Here we present the results of a kinetic characterization of the interaction of Escherichia coli RNA polymerase with UP element-containing promoters which by virtue of consensus or near-consensus sequence features should be among the most optimal that can be encountered by Escherichia coli RNA polymerase. We show that for such promoters, (1) the second-order rate constant describing formation of the initial (closed) complex is close to that expected for a diffusion-limited process, (2) the extent of activation by the UP element is temperature-sensitive, (3) the UP element accelerates a process after DNA binding by RNA polymerase, and (4) the presence of the UP element delays promoter clearance upon addition of nucleoside triphosphates to preformed RNA polymerase-promoter complexes. Finally, we provide evidence in support of models which describe the DNA melting process accompanying open complex formation as initiating in the -10 promoter region and progressing in the downstream direction.

Erysipelothrix rhusiopathiae: an uncommon but ever present zoonosis

Erysipelothrix rhusiopathiae is an important animal pathogen with a worldwide distribution, yet this zoonotic infection is rarely reported in humans. Three cases of E. rhusiopathiae infection, which illustrate the varied clinical presentations of this pathogen in humans, are presented together with the pathological findings and treatment regimens.

Identifying the integrated electromyographic threshold using different muscles during incremental cycling exercise

BACKGROUND

The purpose of this study was to identify the IEMG threshold in the vastus lateralis (VL) and rectus femoris (RF) muscles during progressive, incremental exercise and to relate these thresholds to the ventilatory threshold (Tvent).

METHODS

Ten men (age: 23.40 +/- 3.13 yrs, mass 76.64 +/- 8.13 kg, % fat: 8.81 +/- 2.32, VO2peak: 66.37 +/- 10.61 ml.kg.min-1) with cycling experience completed a graded exercise test on a cycle ergometer by cycling at 90 rpm using 45 watt increments at two minute intervals. Oxygen uptake was measured continuously and the IEMG activity of the VL and RF was calculated during the last 5 s of each minute. The mean for the IEMG of 6 to 7 complete pedal revolutions was used as the final value. Tvent was visually identified using the VE/VO2 and V-slope methods. The IEMG threshold for VL and RF was visually identified at the inflection point where a non-linear increase in IEMG occurred. Comparisons between Tvent and IEMG thresholds were made using dependent means "t"-tests.

RESULTS

Results showed that an IEMG threshold was identified in all 10 subjects for the RF, but in only 5 of 10 subjects for the VL. However, when identified, the IEMG threshold for VL was similar to RF.VO2 at IEMG threshold for RF (3.53 +/- 0.36 L.min-1) was not significantly different from Tvent (3.36 +/- 0.42 L.min-1).

CONCLUSIONS

These results show that the IEMG threshold is more consistently detected in the RF compared to VL during incremental cycling exercise. In addition, the IEMG threshold for RF was closely related to Tvent and provides an alternative means to assess the ventilatory threshold.

An innate natural antibody is reactive with a cryptic sequence of lactoferrin exposed on sperm head surface

Lactoferrin (LF), an 80-kDa glycoprotein of ubiquitous occurrence in body fluids, is multifunctional and capable of assuming different configurations to serve those functions. The capacity of LF to undergo endocytosis and the recent demonstration of LF binding to sequence specific DNA indicate that a function or capability of LF, in addition to iron chelation, bacteriostasis, and receptor-specific lymphocyte binding, may be that of gene activation or silencing. The data of this report present a human physiological system, that of sperm entry into the oocyte in performance of fertilization in which, since LF is a component of the sperm protein coat, that capability could be expressed. However, the configuration of LF in that locus is one in which a revealed cryptic sequence provides the specific binding site for a natural antibody present in the fertilization milieu. The presence of that antibody suggests that a system of control of the potential interaction of LF with the intra-ooplasmic DNA, that of gametes or pronuclei, is operative. The configuration of LF on the sperm surface and designation of the reactive site for the natural antibody were enabled by a monoclonal antibody secreted by a hybridoma derived from a human cord blood B cell. Thus, in addition to information concerning the molecular flexibility of LF, these observations support the proposition that the repertoire of natural antibodies provides an innate homeostatic system, with each antibody serving a specific role.

Innate natural antibodies. Primary roles indicated by specific epitopes

Two members of a unique class of natural antibodies have been identified in all of a large cohort of sera from clinically normal humans of broad age distribution. By means of a series of 10-12 mer peptides the epitope for each of those antibodies was characterized with regard to amino acid identity and conformation. Similar epitope specificity was revealed for the IgM isotopes of cord blood and early post natal sera and for IgM and IgG of adult sera, suggesting that the class of natural antibodies represented by the two identified in this study includes those genomically coded for at their effector level of maturation in the B cells of the neonate. Assay of series of specimens from each of four clinically normal adults revealed that those two natural antibodies are present at relatively constant titer, unique to each individual, over four to five and a half year periods. Those observations imply that the primary function of that class of natural antibodies may be related to maintenance of homeostasis and the molecular identity of each of the two epitopes suggests a role, for each, as monitor or control in intracellular traffic. The previous identification of those epitopes in a conserved protein of HIV also provides support for the proposition that a secondary function of natural antibodies, arising from fortuitous coincidence of the identity of the epitopes, may be that of early defense against infectious invaders.