Long-term effects of ungulates on phytophagous insects

Abstract.  1. Most plants interact with a diverse suite of herbivores, allowing the opportunity for the existence of positive and negative interactions between highly dissimilar organisms. However, most studies on herbivorous interactions have been performed under the assumption that they occur mainly between similar species. Consequently, ecologists are still far from a full understanding of the ecological factors that determine insect population dynamics.
2. In this study, a 7-year field experiment was conducted that manipulated the presence of ungulates to evaluate their effects on the abundance, attack rate, and survival of four guilds of co-occurring herbivorous insects living on the same host plant: seed predators, stem borers, gall makers and sap suckers. These four guilds differed in habits and behaviour, the first three being sessile and endophytic and the last being free-living.
3. This study shows that the abundance of all four guilds was negatively affected by ungulates. However, the effect on attack rate differed among guilds, as mammals do not affect the seed predator attack rate. Ungulates also differentially affected insect survival, ingesting only seed predators and gall makers.
4. In summary, this study suggests that diverse mechanisms may affect different insect guilds in different ways. Therefore, competition between disparate herbivores appears to be complex and can be provoked by multiple mechanisms.     

Antisense RNA decreases AP33 gene expression and cytoadherence by <Emphasis Type="Italic">T. vaginalis</Emphasis>

Background  

Host parasitism by Trichomonas vaginalis is complex. Adherence to vaginal epithelial cells (VECs) is mediated by surface proteins. We showed before that antisense down-regulation of expression of adhesin AP65 decreased amounts of protein, which lowered levels of T. vaginalis adherence to VECs. We now perform antisense down-regulation of expression of the ap33 gene to evaluate and confirm a role for AP33 in adherence by T. vaginalis. We also used an established transfection system for heterologous expression of AP33 in T. foetus as an additional confirmatory approach.     

Hydrologic regulation of gross methyl chloride and methyl bromide uptake from Alaskan Arctic tundra

The Arctic tundra has been shown to be a potentially significant regional sink for methyl chloride (CH₃Cl) and methyl bromide (CH₃Br), although prior field studies were spatially and temporally limited, and did not include gross flux measurements. Here we compare net and gross CH₃Cl and CH₃Br fluxes in the northern coastal plain and continental interior. As expected, both regions were net sinks for CH₃Cl and CH₃Br. Gross uptake rates (−793 nmol CH₃Cl m⁻² day⁻¹ and −20.3 nmol CH₃Br m⁻² day⁻¹) were 20–240% greater than net fluxes, suggesting that the Arctic is an even greater sink than previously believed. Hydrology was the principal regulator of methyl halide flux, with an overall trend towards increasing methyl halide uptake with decreasing soil moisture. Water table depth was one of the best predictors of net and gross uptake, with uptake increasing proportionately with water table depth. In drier areas, gross uptake was very high, averaging −1201 nmol CH₃Cl m⁻² day⁻¹ and −34.9 nmol CH₃Br m⁻² day⁻¹; in flooded areas, gross uptake was significantly lower, averaging −61 nmol CH₃Cl m⁻² day⁻¹ and −2.3 nmol CH₃Br m⁻² day⁻¹. Net and gross uptake was greater in the continental interior than in the northern coastal plain, presumably due to drier inland conditions. Within certain microtopographic features (low‐ and high‐centered polygons), uptake rates were positively correlated with soil temperature, indicating that temperature played a secondary role in methyl halide uptake. Incubations suggested that the inverse relationship between water content and methyl halide uptake was the result of mass transfer limitation in saturated soils, rather than because of reduced microbial activity under anaerobic conditions. These findings have potential regional significance, as the Arctic is expected to become warmer and drier due to anthropogenic climate forcing, potentially enhancing the Arctic sink for CH₃Cl and CH₃Br.     

Understanding down-regulation of photosynthesis under water stress: future prospects and searching for physiological tools for irrigation management

Photosynthetic down-regulation and/or inhibition under water stress conditions are determinants for plant growth, survival and yield in drought-prone areas. Current knowledge about the sequence of metabolic events that leads to complete inhibition of photosynthesis under severe water stress is reviewed. An analysis of published data reveals that a key regulatory role for Rubisco in photosynthesis is improbable under water stress conditions. By contrast, the little data available for other Calvin cycle enzymes suggest the possibility of a key regulatory role for some enzymes involved in the regeneration of RuBP. There are insufficient data to determine the role of photophosphorylation. Several important gaps in our knowledge of this field are highlighted. The most important is the remarkable scarcity of data about the regulation/inhibition of photosynthetic enzymes other than Rubisco under water stress. Consequently, new experiments are urgently needed to improve our current understanding of photosynthetic down-regulation under water stress. A second gap is the lack of knowledge of photosynthetic recovery after irrigation of plants which have been subjected to different stages of water stress. This knowledge is necessary in order to match physiological down-regulation by water stress with controlled irrigation programmes.     

STUDY ON THE PROLIFERATIVE STATE OF HAEMOPOIETIC STEM CELLS (CFU)

Hydroxyurea was used to study the proliferation rate of haemopoietic stem cells (CFUJ in normal mice, after irradiation or transplantation into irradiated recipients. It was demonstrated that the proliferation rate of endogenous CFU_S (endo-CFU,) and exogenous CFU_S (exo-CFU_s) are identical. After irradiation (650 R) the surviving endo-CFU_s begin to proliferate immediately. By contrast exo-CFU, transplanted into the irradiated recipient mouse (850 R), begin to proliferate only after about 30 hr. However, injection of isoproterenol (which stimulates adenyl cyclase) or dibutyryl cyclic adenosine 3′,5′-monophosphate shortly after marrow cell graft, triggers the transplanted CFU_S into cell cycle as shown by an almost immediately increased sensitivity to hydroxyurea. Isoproterenol is capable of inducing DNA synthesis also in stem cells of normal mice but it takes about 20 hr before CFU, become to be increasingly sensitive to hydroxyurea.     

Genomic changes and HPV type in cervical carcinoma

To identify chromosomal regions that may include the loci of abnormally expressed cellular genes and may be specifically altered depending on the histological subtype of the tumor, we studied primary cervical carcinoma using CGH and HPV genotyping. Eighty-seven percent of the primary tumors were positive for DNA of a "high-risk" HPV type (e.g., 16 or 18). In the cervical carcinomas, without reference to histologic subtype, overrepresentation of chromosome 3q was the most consistent chromosomal aberration with underrepresentation of chromosome 3p also a frequent finding. Chromosome arms 1q, 5p, 20q, and Xq were overrepresented in many tumors and 3p loss and 5p, 8q, and 16q gain were only associated with squamous cell carcinoma in this series.     

Comparison of techniques for the measurement of skin temperature during exercise in a hot,humid environment

Exercising or working in a hot, humid environment can results in the onset of heat-related illness when an individual''s temperature is not carefully monitored. The purpose of the present study was to compare three techniques (data loggers, thermal imaging, and wired electrodes) for the measurement of peripheral (bicep) and central (abdominal) skin temperature. Young men and women (N = 30) were recruited to complete the present study. The three skin temperature measurements were made at 0 and every 10-min during 40-min (60% VO₂max) of cycling in a hot (39±2°C), humid (45±5% RH) environment. Data was statistically analyzed using the Bland-Altman method and correlation analysis. For abdominal skin temperature, the Bland-Altman limits of agreement indicated that data loggers (1.5) were a better index of wired than was thermal imaging (3.5), For the bicep skin temperature the limits of agreement was similar between data loggers (1.9) and thermal (1.9), suggesting the both were suitable measurements. We also found that when skin temperature exceeded 35°C, we observed progressively better prediction between data loggers, thermal imaging, and wired skin sensors. This report describes the potential for the use of data loggers and thermal imaging to be used as alternative measures of skin temperature in exercising, human subjects.     

Effects of 16 genetic variants on fasting glucose and type 2 diabetes in South Asians: ADCY5 and GLIS3 variants may predispose to type 2 diabetes

BackgroundThe Meta-Analysis of Glucose and Insulin related traits Consortium (MAGIC) recently identified 16 loci robustly associated with fasting glucose, some of which were also associated with type 2 diabetes. The purpose of our study was to explore the role of these variants in South Asian populations of Punjabi ancestry, originating predominantly from the District of Mirpur, Pakistan.Conclusions/SignificanceAlthough only the SLC30A8 rs11558471 SNP was nominally associated with fasting glucose in our study, the finding that 12 out of 16 SNPs displayed a direction of effect consistent with European studies suggests that a number of these variants may contribute to fasting glucose variation in individuals of South Asian ancestry. We also provide evidence for the first time in South Asians that alleles of SNPs in GLIS3 and ADCY5 may confer risk of type 2 diabetes.     

Effects of age,territoriality and breeding on survival of Bonelli’s Eagle Aquila fasciata

Survival typically contributes most to population trends in long‐lived birds and its accurate estimation is therefore vital for population management and conservation. We evaluated the effects of age, territoriality and reproduction on survival in Bonelli’s Eagle Aquila fasciata through multistate capture‐mark‐recapture analyses on a long‐term dataset. Monitoring was carried out in southeast France (1990–2008) and involved the surveying of territorial Eagles, the marking of fledged chicks, and the recording of resightings and recoveries of marked non‐territorial and territorial birds. Survival improved with age, but territoriality was not retained in the best model; yearly survival was estimated at 0.479 for fledglings (to 1 year of age), 0.570 for 1‐ and 2‐year‐olds, and 0.870 for 3‐year‐old and older individuals. The second best model supported a further increase in survival from 3‐year‐olds (0.821) to older individuals (0.880). In the third best supported model, territoriality enhanced survival, but only in 2‐year‐olds (0.632 vs. 0.562 for non‐territorial). We found no correlation between the previous breeding stage and future survival, consistent with the long lifespan of the study species. Nevertheless, 4‐year‐old and older successful breeders were more likely to breed the following year than failed adult breeders (0.869 vs. 0.582), suggesting that the cost of reproduction is small in comparison with the variation in quality among individuals or their territories.