Are Reproductive Traits Related to Pollen Limitation in Plants? A Case Study from a Central European Meadow

The deficiency of pollen grains for ovule fertilization can be the main factor limiting plant reproduction and fitness. Because of the ongoing global changes, such as biodiversity loss and landscape fragmentation, a better knowledge of the prevalence and predictability of pollen limitation is challenging within current ecological research. In our study we used pollen supplementation to evaluate pollen limitation (at the level of seed number and weight) in 22 plant species growing in a wet semi-natural meadow. We investigated the correlation between the pollen limitation index (PL) and floral traits associated with plant reproduction or pollinator foraging behavior. We recorded significant pollen limitation for approximately 41% of species (9 out of 22 surveyed). Seven species had a significant positive response in seed production and two species increased in seed weight after pollen supplementation. Considering traits, PL significantly decreased with the number of pollinator functional groups. The relationship of PL with other examined traits was not supported by our results. The causes of pollen limitation may vary among species with regard to (1) different reproductive strategies and life history, and/or (2) temporary changes in influence of biotic and abiotic factors at a site.

Self-compatibility and autonomous selfing of plants in meadow communities

One of the most fundamental, although controversial, questions related to the evolution of plant mating systems is the distribution of outcrossing rates. Self-compatibility, and especially autonomous self-pollination, can become particularly beneficial in anthropogenically degraded habitats with impoverished pollinator assemblages and increased pollen limitation. In a hand-pollination experiment with 46 meadow plants from the Železné hory Mts., Czech Republic, we evaluated the species' ability to adopt different mating systems. For a subset of the species, we also tested seed germination for inbreeding depression. Subsequently, we analysed relationships between the species' mating systems and 12 floral and life-history traits. We found a relatively discrete distribution of the studied species into four groups. Fully and partially self-incompatible species formed the largest group, followed by self-compatible non-selfers and mixed mating species. The germination experiment showed an absence of inbreeding depression in 19 out of 22 examined species. Nectar sugar per flower, nectar sugar per shoot and dichogamy were significant associated with the mating system. Spontaneous selfing ability and self-incompatibility in species of the meadow communities had a discrete distribution, conforming to the general distribution of mating and breeding systems in angiosperms. The low frequency of spontaneous selfers and the lack of inbreeding depression at germination suggest the existence of a selection against selfing at the later ontogenetic stages. Some floral traits, such as the level of dichogamy and amount of nectar reward, may strongly impact the balance between selfing and outcrossing rates in the self-compatible species and thus shape the evolution of mating systems.

The role of ultraviolet reflectance and pattern in the pollination system of Hypoxis camerooniana (Hypoxidaceae)

Apart from floral morphology and colours perceived by the human eye, ultraviolet (UV) reflectance acts as an important visual advertisement of numerous flowering plant species for pollinators. However, the effect of UV signalling on attracting pollinators of particular plant species is still insufficiently studied, especially in the Afrotropics. Therefore, we studied the pollination system of Hypoxis camerooniana in montane grasslands of Mount Cameroon, West/Central Africa. We focused mainly on the effects of the flowers' UV reflectance on its visitors. We experimentally removed UV reflection from petals either completely or partially. Thereafter, flower visitors were recorded and pistils were collected post-flowering to quantify germinated pollen tubes per treatments. The most important visitors were bees, followed by flies. Due to their contacts with reproductive organs bees are considered as the primary pollinators. Visitation rates were lower when UV reflectance was completely removed, whereas the decrease of frequency on half-treated flowers did not differ significantly from control treatments. The complete removal of UV also affected bees' landing behaviour, but not that of flies. We showed that the presence of UV reflectance is more important than UV pattern for bees visiting flowers of H. camerooniana. We hypothesize that exploiting all flowers irrespective of their pattern can be more efficient for pollinators in the open grasslands of high altitudes to spot these relatively scarce flowers by their UV reflectance. Furthermore, we highlight the necessity of both experimental and natural controls in similar studies to control for additional effects of the used UV manipulations. Many plants advertise their flowers with UV reflectance visible to their insect visitors. By manipulating the UV reflectance and pattern of Hypoxis camerooniana in the Afromontane grasslands of Mount Cameroon, we have shown how crucial it is for the predominant visitor, bees. Both bees' preferences for flowers and their behaviour during visits are influenced by changes in UV reflectance. However, the presence of some UV signal is more important than the specific pattern. Especially in montane grasslands with higher UV irradiation, the UV floral colours are important for recognition of flowers by potential pollinators.

Effects of Leukaemia Inhibitory Factor Receptor on the Early Stage of Osteogenic Differentiation of Human Bone Marrow Mesenchymal Cells

Most people worldwide suffer from dental caries. Only a small part of the population is cariesresistant and the reason for this resistance in unknown. Only a few studies compared the saliva protein composition of persons with carious teeth and persons with no caries. Our study is the first to relate proteomic analysis of the caries aetiology with gender. In this study, we compared the differences in the abundances of proteins in the saliva between cariesresistant and caries-susceptible females and males by nano-liquid chromatography-tandem mass spectrometry (Label-Free Quantitative Proteomics). Our results demonstrate that the observed differences in the protein levels might have an influence on anticaries resistance. A total of 19 potential markers of tooth caries were found, for example proteins S100A8 and annexin A1 with higher expression in the cariessusceptible group in comparison with the caries-free group and mucin-5B, lactoferrin, lysozyme C with higher expression in the caries-free group in comparison with the caries-susceptible group. The presented study is the first complex proteomic and gender project where the saliva protein content of caries-free and caries-susceptible persons were compared by label-free MS. The newly detected potential protein markers of dental caries can be a good basis for further research and for possible future therapeutic use.

Epidemiology of selected Mycobacterium tuberculosis complex members in the Czech Republic in 2000-2016

The paper concerns the epidemiology of Mycobacterium tuberculosis complex (MTBC) members except for M. tuberculosis in the Czech Republic in 2000 to 2016. M. bovis was confirmed in 18 patients. M. caprae was diagnosed in two patients in 2001 and 2016 and M. microti in one patient in 2007. M. africanum was detected in one HIV infected woman from Nigeria in 2011. As regards animals, M. pinnipedii was isolated in 2009 from one Southern sea lion (Otaria flavescens) imported from Germany. In 2002, M. caprae was isolated from two Bactrian camels (Camelus ferus) kept in a zoological garden. M. tuberculosis was isolated from one dog in 2004 and from two domestic pigs in 2007. In both cases, the source of M. tuberculosis was an infected patient. Upon examination of 3 727 environmental samples of water and sediments, none of the MTBC members was detected in the stu-died period. Infected persons coming from M. africanum endemic countries (especially West African countries) and infected animals can be considered as the current risk factors for transmission of MTBC species. If the epidemiological situation remains as it is now, there is no risk of transmission of MTBC species via milk or unpasteurised dairy products. Keywords: mycobacterial ecology - domestic and wild animals - food safety.

Is the scaling relationship between carbohydrate storage and leaf biomass in meadow plants affected by the disturbance regime?

BACKGROUND AND AIMS

Below-ground carbohydrate storage is considered an adaptation of plants aimed at regeneration after disturbance. A theoretical model by Iwasa and Kubo was empirically tested which predicted (1) that storage of carbohydrates scales allometrically with leaf biomass and (2) when the disturbance regime is relaxed, the ratio of storage to leaf biomass increases, as carbohydrates are not depleted by disturbance.

METHODS

These ideas were tested on nine herbaceous species from a temperate meadow and the disturbance regime was manipulated to create recently abandoned and mown plots. Just before mowing in June and at the end of the season in October, plants with below-ground organs were sampled. The material was used to assess the pool of total non-structural carbohydrates and leaf biomass.

KEY RESULTS

In half of the cases, a mostly isometric relationship between below-ground carbohydrate storage and leaf biomass in meadow plants was found. The ratio of below-ground carbohydrate storage to leaf biomass did not change when the disturbance regime was less intensive than that for which the plants were adapted.

CONCLUSIONS

These findings (isometric scaling relationship between below-ground carbohydrate storage and leaf biomass; no effect of a relaxed disturbance regime) imply that storage in herbs is probably governed by factors other than just the disturbance regime applied once in a growing season.

The nectar spur is not only a simple specialization for long-proboscid pollinators

Since the time of Darwin, biologists have considered the floral nectar spur to be an adaptation representing a high degree of plant specialization. Nevertheless, some researchers suggest that nature is more complex and that even morphologically specialized plants attract a wide spectrum of visitors. We observed visitors on Impatiens burtonii (Balsaminaceae) and measured the depth of the proboscis insertion into the spur, the distance of the nectar surface from the spur entrance and the visitor's effectiveness. The hoverfly Melanostoma sp., with the shortest proboscis, was most active early in the morning and fed on pollen and nectar near the spur entrance. The honeybee Apis mellifera and the hoverfly Rhingia mecyana were the most frequent visitors before and after noon, respectively. Although R. mecyana, the only visitor able to reach the end of the spur, was the most frequent, it did not deposit the largest number of pollen grains per visit. Nectar spurs may function as complex structures allowing pollination by both short- and long-proboscid visitors and separating their spatial and temporal niches. Spurred plants should be considered as more generalized and exposed to more diverse selection pressures than previously believed.

Asymmetric competition for nectar between a large nectar thief and a small pollinator: an energetic point of view

There are two alternative hypotheses related to body size and competition for restricted food sources. The first one supposes that larger animals are superior competitors because of their increased feeding abilities, whereas the second one assumes superiority of smaller animals because of their lower food requirements. We examined the relationship between two unrelated species of different size, drinking technique, energy requirements and roles in plant pollination system, to reveal the features of their competitive interaction and mechanisms enabling their co-existence while utilising the same nectar source. We observed diurnal feeding behaviour of the main pollinator, the carpenter bee Xylocopa caffra and a nectar thief, the northern double-collared sunbird Cinnyris reichenowi on 19 clumps of Hypoestes aristata (Acanthaceae) in Bamenda Highlands, Cameroon. For comparative purpose, we established a simplistic model of daily energy expenditure and daily energy intake by both visitor species assuming that they spend all available daytime feeding on H. aristata. We revealed the energetic gain-expenditure balance of the studied visitor species in relation to diurnal changes in nectar quality and quantity. In general, smaller energy requirements and related ability to utilise smaller resources made the main pollinator X. caffra competitively superior to the larger nectar thief C. reichenowi. Nevertheless, sunbirds are endowed with several mechanisms to reduce asymmetry in exploitative competition, such as the use of nectar resources in times of the day when rivals are inactive, aggressive attacks on carpenter bees while defending the nectar plants, and higher speed of nectar consumption.

The Potential Benefit of Intracarpal Pressure Measurement in Endoscopic Carpal Tunnel Syndrome Surgery – An Analysis of EMG Findings and Pressure Values

Endoscopic carpal tunnel syndrome surgery is a modern minimally invasive method of carpal tunnel decompression. However, the method does also have its critics, who emphasize that there is an increased rate of complications in comparison to open procedures. To further improve and optimize results of endoscopic surgery we used an intracarpal pressure sensor to verify the effect of carpal tunnel decompression. The endoscopic single portal approach was used in all cases. Median nerve conduction studies were performed prior to and 3 months after surgery. Two groups, those with pressure studies and those without, were then compared according to several EMG parameters such as: median nerve distal motor latency, amplitude of motor response, sensory nerve conduction velocity to the index finger, and amplitude of sensory nerve action potential. In both groups, we observed similarly significant improvements in all conduction parameters, except the amplitude of motor response, which did not change in either group, i.e. no difference in postoperative EMG between the two groups was observed. Despite this fact, intracarpal pressure measurement is still useful in localising the point in which the median nerve is compressed and provides valuable functional information on the level decompression achieved.

Decolorization of organic dyes by gold nanoflowers prepared on reduced graphene oxide by tea polyphenols

The green approaches for chemical syntheses are becoming important in various fields comprising chemical synthesis.

Effects of disturbance regime on carbohydrate reserves in meadow plants

Carbohydrate storage enables plants to tolerate both seasonally unfavourable conditions and recover from disturbance. Although short-term changes in storage levels due to disturbance are fairly well known, less is known about long-term changes in storage levels, especially in response to cessation of repeated disturbance. Additionally, whereas it is presumably the total amount (pool) of storage carbohydrate reserves that is of importance, typically carbohydrate concentrations are measured instead, as a proxy. We assessed changes in carbohydrate concentrations and pools in storage organs and changes in above- versus belowground biomass in response to mowing cessation in nine herbs from two meadows (dry and wet) at the (June) peak of vegetation development and the (October) growing season end 1 and 3 years after the change in the disturbance regime. We tested three hypotheses: (1) storage will increase with abandonment of mowing only in the first year after disturbance cessation, but not further increase subsequently, as high storage would hinder competitive ability; (2) storage will increase towards the end of the season in both disturbed and undisturbed plants; and (3) changes in carbohydrate concentrations are accurate predictors of changes in pools. Although species-specific changes in carbohydrate reserves occurred in the wet meadow, more general trends appeared in the dry meadow. There, plants accumulated higher carbohydrate reserves at the end of the season, especially in unmown plots. However, the reserves for plants in both disturbance regimes were the same at the growing season peak (June) in both examined years. The increase in storage of carbohydrates on unmown plots in October was manifested by increases of both storage organ biomass and carbohydrate concentration, whereas in mown plots, it was due only to increased carbohydrate concentration. Although concentrations and pools represent different aspects of plant carbohydrate economy, concentrations will represent short-term responses to changed disturbance regimes.

Kinetic properties of adenosine triphosphate sulfurylase of intestinal sulfate-reducing bacteria

The investigation of specific activity of ATP sulfurylase and kinetic properties of the enzyme in cell-free extracts of intestinal bacterial strains Desulfovibrio piger Vib-7 and Desulfomicrobium sp. Rod-9 is presented. The microbiological, biochemical, biophysical and statistical methods were used in the work. The optimal temperature (35°C) and pH 8.0-8.5 for enzyme reaction were determined. An analysis of kinetic properties of ATP sulfurylase has been carried out. Initial (instantaneous) reaction velocity (V0), maximum amount of the product of reaction (Pmax), the reaction time (half saturation period, τ) and maximum velocity of the ATP sulfurylase reaction (Vmax) have been defined. Michaelis constants (Km(Sulfate), Km(ATP), Km(APS), and Km(Pyrophosphate)) of the enzyme reaction were demonstrated for both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains.

Pollinator-induced twisting of flowers sidesteps floral architecture constraints

Specific pollen placement by zygomorphic flowers on pollinators is one of the key innovations of angiosperm evolution [1]. In most phylogenetic lineages that have evolved zygomorphic flowers, reproductive organs are positioned either in the lower or upper part of the flower. Although these specific positions largely enhance pollen economy, they also represent architectural constraints such that flowers are able to place pollen only on the dorsal or ventral part of pollinators' bodies [2]. Such constraints can lead to interspecific pollen placement in situations where phylogenetically related species with the same floral architecture share pollinators [3].

[Retinal tamponade with silicone oil - long term results]

AIM

The aim of this study is to evaluate the frequency and efficacy of silicone oil (SO) retinal tamponade in various retinal diseases. The incidence of silicone oil tamponade according to individual indications, incidence of complications and duration of tamponade were evaluated in the study.

MATERIAL AND METHODS

A retrospective study included 510 eyes that were operated on pars plana vitrectomy (PPV) from January 2010 to December 2012. In our group we evaluated 241 men and 189 women, age 4-84 years, mean 62 years . Follow-up period was 12 to 48 months, an average of 27.5 months . We evaluated 253 eyes with diabetic retinopathy, 201 eyes with regmatogenous retinal detachment, 34 eyes with endophthalmitis and 22 eyes after the injury.

RESULTS

In 253 diabetic retinopathy eyes (DR) silicone oil tamponade was indicated in 56 eyes (22.1 %). Silicone oil removal was done on 22 eyes (39.3 %), the average length of SO tamponade was 9.7 months. After SO removal BCVA (best corrected visual acuity) 0,1 and worse had 12 eyes (54,6 %), 0,2 - 0,4 had 5 eyes (22,7 %) and 0,5 or better had 5 eyes (22,7 %). Permanent SO tamponade was left in 34 diabetic retinopathy eyes (60.7 %). Secondary glaucoma (SG) was present in 40 eyes (71.5 %). In 201 retinal detachment (RD) eyes silicone oil tamponade was used in 76 eyes (37.8 %). Secondary glaucoma was present in 31 eyes (40.8 %). Silicone oil was successfully removed in 40 eyes (52.6 %), the average length of tamponade was 9.2 months. In this group BCVA 0,1 and worse had 22 eyes (55,0 %), 0,2 - 0,4 had 15 eyes (37,5 %) and 0,5 or better had 3 eyes (7,5 %). 36 eyes (47,4 %) RD eyes had permanent silicone oil tamponade. In a group of 34 eyes with endophthalmitis SO tamponade was used in 16 eyes (47 %). Secondary glaucoma was present in 3 eyes (18.8 %). Silicone oil removal we did in 11 eyes (68.8 %), the average length of SO tamponade was 5.5 months. After SO removal BCVA 0,1 and worse had 3 eyes (27,2 %), 0,2 - 0,4 had 4 eyes (36,4 %) and 0,5 or better had 4 eyes (36,4 %). 5 eyes (31.2 %) with endophthalmitis had permanent SO tamponade. Out of 22 eyes with eye injuries SO tamponade was used in 14 eyes (63.6 %). 5 eyes (35.7 %) had secondary glaucoma. In 9 eyes (64.3 %) silicone oil was removed, the average length of tamponade was 9.1 months. In this group BCVA 0,1 and worse had 6 eyes (66,7 %), 0,2-0,4 had 1 eye (11,1 %) and 0,5 or better had 2 eyes (22,2 %). Permanent silicone oil tamponade had 5 eyes (35,7 %). In group of 56 phakic eyes (100 %) with silicone oil tamponade we followed cataract progression. 26 eyes (40 %) had cataract surgery in 6 month follow up, 47 eyes (72.3 %) in 1 year follow up and 57 eyes (87.7 %) had cataract surgery in 3 years follow up.

CONCLUSION

Silicone oil tamponade is the method of choice for long-term and stable retinal tamponade, which is important for good functional outcomes of the surgical intervention. The silicone oil tamponade of the retina is nowadays irreplaceable, despite of its potential risks and complications.

[Surgical treatment of the idiopatic macular hole - our experience]

AIM

To evaluate the results of the idiopathic macular hole (IDM) surgical treatment. Surgery included pars plana vitrectomy (PPV) with the removal (peeling) of internal limiting membrane (ILM) and intraocular tamponade with a diluted expanding gas.

MATERIAL AND METHODS

A retrospective study included 100 eyes of 96 patients (10 men and 86 women) with IDM, that were operated at II. Eye Clinic SZU in Banska Bystrica from August 2008 to August 2012. Patients age ranged from 48 to 86 years, average 69.3 years. Mean follow-up time was 39.2 months. All patients underwent PPV with the ILM peeling. Intraocular air tamponade was used in 1-case, 16 % SF6 84-times and 12 % C3F8 15 times.

RESULTS

Anatomical success of the operation was evaluated with OCT examination. After primary operation there were 92 (92 %) closed macular holes in our study. In 6 patients (6 %), we decided to reoperate with gas tamponade (SF6 2-times, C3F8 4 times). After the reoperations final anatomical success in our study was 97 eyes (97 %). Functional results we examined with Snellen. Improved best corrected visual acuity (BCVA) was observed in 85 eyes (85 %), no changes in 11 eyes (11 %), and deterioration in 4 eyes (4 %). Improvement in vision was following: 1 line - 18 eyes, 2 lines - 20 eyes, 3 lines - 18 eyes, 4 lines - 11 eyes, 5 or more lines in 18 eyes.

CONCLUSION

Pars plana vitrectomy with ILM peeling and gas tamponade is highly effective and safe treatment of idiopathic macular hole.Key words: idiopathic macular hole, pars plana vitrectomy, expanding gas.

Generalization versus specialization in pollination systems: visitors, thieves, and pollinators of Hypoestes aristata (Acanthaceae)

Many recent studies have suggested that the majority of animal-pollinated plants have a higher diversity of pollinators than that expected according to their pollination syndrome. This broad generalization, often based on pollination web data, has been challenged by the fact that some floral visitors recorded in pollination webs are ineffective pollinators. To contribute to this debate, and to obtain a contrast between visitors and pollinators, we studied insect and bird visitors to virgin flowers of Hypoestes aristata in the Bamenda Highlands, Cameroon. We observed the flowers and their visitors for 2-h periods and measured the seed production as a metric of reproductive success. We determined the effects of individual visitors using 2 statistical models, single-visit data that were gathered for more frequent visitor species, and frequency data. This approach enabled us to determine the positive as well as neutral or negative impact of visitors on H. aristata's reproductive success. We found that (i) this plant is not generalized but rather specialized; although we recorded 15 morphotaxa of visitors, only 3 large bee species seemed to be important pollinators; (ii) the carpenter bee Xylocopa cf. inconstans was both the most frequent and the most effective pollinator; (iii) the honey bee Apis mellifera acted as a nectar thief with apparent negative effects on the plant reproduction; and (iv) the close relationship between H. aristata and carpenter bees was in agreement with the large-bee pollination syndrome of this plant. Our results highlight the need for studies detecting the roles of individual visitors. We showed that such an approach is necessary to evaluate the pollination syndrome hypothesis and create relevant evolutionary and ecological hypotheses.