Maintaining historic disturbance regimes increases species' resilience to catastrophic hurricanes

As habitat loss and fragmentation, urbanization, and global climate change accelerate, conservation of rare ecosystems increasingly relies on human intervention. However, any conservation strategy is vulnerable to unpredictable, catastrophic events. Whether active management increases or decreases a system's resilience to these events remains unknown. Following Hurricane Irma's landfall in our habitat restoration study sites, we found that rare ecosystems with active, human‐imposed management suffered less damage in a hurricane's path than unmanaged systems. At the center of Irma's landfall, we found Croton linearis' (a locally rare plant that is the sole host for two endangered butterfly species) survival and population growth rates in the year of the hurricane were higher in previously managed plots than in un‐managed controls. In the periphery of Irma's circulation, the effect of prior management was stronger than that of the hurricane. Maintaining the historical disturbance regime thus increased the resilience of the population to major hurricane disturbance. As climate change increases the probability and intensity of severe hurricanes, human management of disturbance‐adapted landscapes will become increasingly important for maintaining populations of threatened species in a storm's path. Doing nothing will accelerate extinction.     

De-Novo Design of Antimicrobial Peptides for Plant Protection

This work describes the de-novo design of peptides that inhibit a broad range of plant pathogens. Four structurally different groups of peptides were developed that differ in size and position of their charged and hydrophobic clusters and were assayed for their ability to inhibit bacterial growth and fungal spore germination. Several peptides are highly active at concentrations between 0,1 and 1 µg/ml against plant pathogenic bacteria, such as Pseudomonas syringae, Pectobacterium carotovorum, and Xanthomonas vesicatoria. Importantly, no hemolytic activity could be detected for these peptides at concentrations up to 200 µg/ml. Moreover, the peptides are also active after spraying on the plant surface demonstrating a possible way of application. In sum, our designed peptides represent new antimicrobial agents and with the increasing demand for antimicrobial compounds for production of “healthy” food, these peptides might serve as templates for novel antibacterial and antifungal agents.     

Fecal Occult Blood and Fecal Calprotectin as Point-of-Care Markers of Intestinal Morbidity in Ugandan Children with Schistosoma mansoni Infection

Background

Calprotectin is a calcium-binding cytoplasmic protein found in neutrophils and increasingly used as a marker of bowel inflammation. Fecal occult blood (FOB) is also a dependable indicator of bowel morbidity. The objective of our study was to determine the applicability of these tests as surrogate markers of Schistosoma mansoni intestinal morbidity before and after treatment with praziquantel (PZQ).

Methods

216 children (ages 3–9 years old) from Buliisa District in Lake Albert, Uganda were examined and treated with PZQ at baseline in October 2012 with 211 of them re-examined 24 days later for S. mansoni and other soil transmitted helminths (STH). POC calprotectin and FOB assays were performed at both time points on a subset of children. Associations between the test results and infection were analysed by logistic regression.

Results

Fecal calprotectin concentrations of 150–300 µg/g were associated with S. mansoni egg patent infection both at baseline and follow up (OR: 12.5 P = 0.05; OR: 6.8 P = 0.02). FOB had a very strong association with baseline anemia (OR: 9.2 P = 0.03) and medium and high egg intensity schistosomiasis at follow up (OR: 6.6 P = 0.03; OR: 51.3 P = 0.003). Both tests were strongly associated with heavy intensity S. mansoni infections. There was a significant decrease in FOB and calprotectin test positivity after PZQ treatment in those children who had egg patent schistosomiasis at baseline.

Conclusions

Both FOB and calprotectin rapid assays were found to correlate positively and strongly with egg patent S. mansoni infection with a positive ameloriation response after PZQ treatment indicative of short term reversion of morbidity. Both tests were appropriate for use in the field with excellent operational performance and reliability. Due to its lower-cost which makes its scale-up of use affordable, FOB could be immediately adopted as a monitoring tool for PC campaigns for efficacy evaluation before and after treatment.     

Prevalence of Trypanosoma cruzi Infection among People Aged 15 to 89 Years Inhabiting the Department of Casanare (Colombia)

The purpose of this study was to calculate the seroprevalence of Trypanosoma cruzi infection in a sample of inhabitants from a region considered to be at high risk of natural transmission of Chagas disease in Colombia. A cross-sectional study was conducted in subjects from 5 municipalities, recruited in urban and rural locations, distributed by gender according to the demographic information available. Socio-demographic information, history of potential exposure to insect vectors, blood donating, as well as symptoms suggesting cardiac disease were collected using a questionnaire. After giving written informed consent, blood specimens were obtained from 486 people to determine the serologic evidence of past exposure to T. cruzi. Infection was diagnosed when two different tests (ELISA and IHA) were positive. The seroprevalence of antibodies against T. cruzi was 16.91% considering an estimated population of 44,355 aged between 15 and 89 years (95%IC: 13.72 to 20.01). The factors significantly associated with the infection were: 1- Housing materials like vegetable material, adobe or unfinished brick walls; 2- The fact of having previous tests for Chagas disease (regardless of the result). Of note, the mean ages among infected and not infected participants were significantly different (49.19 vs. 41.66, p≤0.0001). Among the studied municipalities, the one with the highest frequency of T. cruzi infection was Nunchia, with 31.15% of the surveyed subjects. Therefore it may be concluded that T. cruzi infection is highly prevalent in the north region of Casanare, in Colombia.     

Role of mTOR Downstream Effector Signaling Molecules in Francisella Tularensis Internalization by Murine Macrophages

Francisella tularensis is an infectious, gram-negative, intracellular microorganism, and the cause of tularemia. Invasion of host cells by intracellular pathogens like Francisella is initiated by their interaction with different host cell membrane receptors and the rapid phosphorylation of different downstream signaling molecules. PI3K and Syk have been shown to be involved in F. tularensis host cell entry, and both of these signaling molecules are associated with the master regulator serine/threonine kinase mTOR; yet the involvement of mTOR in F. tularensis invasion of host cells has not been assessed. Here, we report that infection of macrophages with F. tularensis triggers the phosphorylation of mTOR downstream effector molecules, and that signaling via TLR2 is necessary for these events. Inhibition of mTOR or of PI3K, ERK, or p38, but not Akt signaling, downregulates the levels of phosphorylation of mTOR downstream targets, and significantly reduces the number of F. tularensis cells invading macrophages. Moreover, while phosphorylation of mTOR downstream effectors occurs via the PI3K pathway, it also involves PLCγ1 and Ca²⁺ signaling. Furthermore, abrogation of PLC or Ca²⁺ signaling revealed their important role in the ability of F. tularensis to invade host cells. Together, these findings suggest that F. tularensis invasion of primary macrophages utilize a myriad of host signaling pathways to ensure effective cell entry.     

Treatment of children with high grade glioma with nimotuzumab: A 5-y institutional experience

Brain tumors are a major cause of cancer-related mortality in children. Overexpression of epidermal growth factor receptor (EGFR) is detected in pediatric brain tumors and receptor density appears to increase with tumor grading. Nimotuzumab is an IgG1 antibody that targets EGFR. Twenty-three children with high-grade glioma (HGG) were enrolled in an expanded access program in which nimotuzumab was administered alone or with radio-chemotherapy. The mean number of doses was 39. Nimotuzumab was well-tolerated and treatment with the antibody yielded a survival benefit: median survival time was 32.66 mo and the 2-y survival rate was 54.2%. This study demonstrated the feasibility of prolonged administration of nimotuzumab and showed preliminary evidence of clinical benefit in HGG patients with poor prognosis.     

Processing of Human Reduction Mammoplasty and Mastectomy Tissues for Cell Culture

Experimental examination of normal human mammary epithelial cell (HMEC) behavior, and how normal cells acquire abnormal properties, can be facilitated by in vitro culture systems that more accurately model in vivo biology. The use of human derived material for studying cellular differentiation, aging, senescence, and immortalization is particularly advantageous given the many significant molecular differences in these properties between human and commonly utilized rodent cells^1-2. Mammary cells present a convenient model system because large quantities of normal and abnormal tissues are available due to the frequency of reduction mammoplasty and mastectomy surgeries.The mammary gland consists of a complex admixture of many distinct cell types, e.g., epithelial, adipose, mesenchymal, endothelial. The epithelial cells are responsible for the differentiated mammary function of lactation, and are also the origin of the vast majority of human breast cancers. We have developed methods to process mammary gland surgical discard tissues into pure epithelial components as well as mesenchymal cells³. The processed material can be stored frozen indefinitely, or initiated into primary culture. Surgical discard material is transported to the laboratory and manually dissected to enrich for epithelial containing tissue. Subsequent digestion of the dissected tissue using collagenase and hyaluronidase strips stromal material from the epithelia at the basement membrane. The resulting small pieces of the epithelial tree (organoids) can be separated from the digested stroma by sequential filtration on membranes of fixed pore size. Depending upon pore size, fractions can be obtained consisting of larger ductal/alveolar pieces, smaller alveolar clusters, or stromal cells. We have observed superior growth when cultures are initiated as organoids rather than as dissociated single cells. Placement of organoids in culture using low-stress inducing media supports long-term growth of normal HMEC with markers of multiple lineage types (myoepithelial, luminal, progenitor)^4-5. Sufficient numbers of cells can be obtained from one individual''s tissue to allow extensive experimental examination using standardized cell batches, as well as interrogation using high throughput modalities.Cultured HMEC have been employed in a wide variety of studies examining the normal processes governing growth, differentiation, aging, and senescence, and how these normal processes are altered during immortal and malignant transformation^4-15,16. The effects of growth in the presence of extracellular matrix material, other cell types, and/or 3D culture can be compared with growth on plastic^5,15. Cultured HMEC, starting with normal cells, provide an experimentally tractable system to examine factors that may propel or prevent human aging and carcinogenesis.     

Effective sociodemographic population assessment of elusive species in ecology and conservation management

Wildlife managers are urgently searching for improved sociodemographic population assessment methods to evaluate the effectiveness of implemented conservation activities. These need to be inexpensive, appropriate for a wide spectrum of species and straightforward to apply by local staff members with minimal training. Furthermore, conservation management would benefit from single approaches which cover many aspects of population assessment beyond only density estimates, to include for instance social and demographic structure, movement patterns, or species interactions. Remote camera traps have traditionally been used to measure species richness. Currently, there is a rapid move toward using remote camera trapping in density estimation, community ecology, and conservation management. Here, we demonstrate such comprehensive population assessment by linking remote video trapping, spatially explicit capture–recapture (SECR) techniques, and other methods. We apply it to three species: chimpanzees Pan troglodytes troglodytes, gorillas Gorilla gorilla gorilla, and forest elephants Loxodonta cyclotis in Loango National Park, Gabon. All three species exhibited considerable heterogeneity in capture probability at the sex or group level and density was estimated at 1.72, 1.2, and 1.37 individuals per km² and male to female sex ratios were 1:2.1, 1:3.2, and 1:2 for chimpanzees, gorillas, and elephants, respectively. Association patterns revealed four, eight, and 18 independent social groups of chimpanzees, gorillas, and elephants, respectively: key information for both conservation management and studies on the species' ecology. Additionally, there was evidence of resident and nonresident elephants within the study area and intersexual variation in home range size among elephants but not chimpanzees. Our study highlights the potential of combining camera trapping and SECR methods in conducting detailed population assessments that go far beyond documenting species diversity patterns or estimating single species population size. Our study design is widely applicable to other species and spatial scales, and moderately trained staff members can collect and process the required data. Furthermore, assessments using the same method can be extended to include several other ecological, behavioral, and demographic aspects: fission and fusion dynamics and intergroup transfers, birth and mortality rates, species interactions, and ranging patterns.     

Generalized additive mixed models for disentangling long‐term trends,local anomalies,and seasonality in fruit tree phenology

Quantifying temporal patterns of ephemeral plant structures such as leaves, flowers, and fruits gives insight into both plant and animal ecology. Different scales of temporal changes in fruits, for example within‐ versus across‐year variability, are driven by different processes, but are not always easy to disentangle. We apply generalized additive mixed models (GAMMs) to study a long‐term fruit presence–absence data set of individual trees collected from a high‐altitude Afromontane tropical rain forest site within Bwindi Impenetrable National Park (BINP), Uganda. Our primary aim was to highlight and evaluate GAMM methodology, and quantify both intra‐ and interannual changes in fruit production. First, we conduct several simulation experiments to study the practical utility of model selection and smooth term estimation relevant for disentangling intra‐ and interannual variability. These simulations indicate that estimation of nonlinearity and seasonality is generally accurately identified using asymptotic theory. Applied to the empirical data set, we found that the forest‐level fruiting variability arises from both regular seasonality and significant interannual variability, with the years 2009–2010 in particular showing a significant increase in the presence of fruits‐driven by increased productivity of most species, and a regular annual peak associated occurring at the end of one of the two dry seasons. Our analyses illustrate a statistical framework for disentangling short‐term increases/decreases in fruiting effort while pinpointing specific times in which fruiting is atypical, providing a first step for assessing the impacts of regular and irregular (e.g., climate change) abiotic covariates on fruiting phenology. Some consequences of the rich diversity of fruiting patterns observed here for the population biology of frugivores in BINP are also discussed.