现生微生物群落形态研究及其对解释埃迪卡拉生物群化石属性的启示

通过对常见微生物种类进行纯培养获得多种微生物菌落形态,并将其与埃迪卡拉生物群化石形态进行对比研究,发现：1）盘状化石Aspidella与圆盘形菌落的轮廓和放射状分布的小脊具有相似性;2）“rangeomorphs”分支状化石与具有次级分支结构的菌落具有某些相似性;3）五边形似棘皮动物化石Arkaruaadami与五边形菌落较为相似;4）两侧对称类化石Kimberella与圆盘形边缘具放射状脊的菌落的表面形态非常相似;5）盘状化石Az—bumaresbrunsae与圆盘形表面具辐射状脊的菌落的轮廓和表面纹饰分布极为相似。以上对比结果表明部分埃迪卡拉生物群化石与微生物菌落形态具有一定的相似性。本研究为埃迪卡拉生物群化石生物属性的解译提供了新思路。     

Nutritional effects of supplementary diets on brood development,biological activities and honey production of Apis mellifera L

The present research work was conducted to assess the impact of nutrient-enriched diet on the physiological activities and subsequently honey yield. Eighteen colonies of Apis mellifera L. were selected from Dera Ismail Khan region, KPK, Pakistan, during the winter and summer seasons, 2019–2020. Five pollen supplement diets were prepared and provided to screen out the palatable one to be fed as pollen alternative nutrition to bee bread. Results of diet consumption regarding mean data for consumption rate displayed that soybean flour enriched artificial diet was maximally consumed (74.34 g) by honey bees per week. Minimum consumption was observed for grinded groundnut enriched diet (64.62 g) which was relatively lesser than the other tested artificial diets. Results of area of worker brood disclosed that soybean flour fortified diet (1489.27 cm²/colony) statistically noteworthy than the other artificial diets whereas control (463.51 cm²/colony) was least effective. Highest bee strength (10.00 bee frames/colony) was noted in the bee colonies fed with soybean flour fortified diet, date paste (8.0 bee frames/colony) was the next effective one, among the tested pollen replacement diets whereas relatively least (5 bee frames/colony) was noticed in case of grinded groundnut. Highest body weight (12.41 g) of neonate bees was noted in case of soybean enriched diet while lowermost (5.31 g) was noted in control bees. Results of wax cell built up and foraging efficiency were also superior in artificial diets than respective control bees. Hence, artificial diets especially soybean-enriched pollen alternative diet can boost up the physiology of honey bee leading to increased honey yield and profit.     

Longevity of U cells of differentiated yeast colonies grown on respiratory medium depends on active glycolysis

Colonies of Saccharomyces cerevisiae laboratory strains pass through specific developmental phases when growing on solid respiratory medium. During entry into the so-called alkali phase, in which ammonia signaling is initiated, 2 prominent cell types are formed within the colonies: U cells in upper colony regions, which have a longevity phenotype and activate the expression of a large number of metabolic genes, and L cells in lower regions, which die more quickly and exhibit a starvation phenotype. Here, we performed a detailed analysis of the activities of enzymes of central carbon metabolism in lysates of both cell types and determined several fermentation end products, showing that previously reported expression differences are reflected in the different enzymatic capabilities of each cell type. Hence, U cells, despite being grown on respiratory medium, behave as fermenting cells, whereas L cells rely on respiratory metabolism and possess active gluconeogenesis. Using a spectrum of different inhibitors, we showed that glycolysis is essential for the formation, and particularly, the survival of U cells. We also showed that β-1,3-glucans that are released from the cell walls of L cells are the most likely source of carbohydrates for U cells.     

Nanocolonies: Detection, cloning, and analysis of individual molecules

Nanocolonies (other names molecular colonies or polonies) are formed upon template nanomolecule (DNA or RNA) amplification in immobilized medium with efficient pore size in the nanometer range. This work deals with the principle, invention, development, and diverse nanocolony applications based on their unique abilities to compartmentalize amplification and expression of individual DNA and RNA molecules, including studying reactions between single molecules, digital molecular diagnostics, in vitro gene cloning and expression, as well as identification of the molecular cis-elements including DNA sequencing, analysis of single-nucleotide polymorphism, and alternative splicing investigation.     

Are workers of Atta leafcutter ants capable of reproduction?

Summary. Workers of most eusocial Hymenoptera can produce sons after queen loss, which (posthumously) benefits the queen and increases worker inclusive fitness. However, the evolutionary loss of worker ovaries has occurred in several lineages, while workers in other taxa may be infertile despite having ovaries. Workers of Atta leafcutter ants only lay trophic eggs in queenright colonies. Although Atta colonies are commonly kept at universities, museums, and zoos, no reports of worker sons in orphaned colonies exist, suggesting that Atta workers are infertile. To explicitly test this, we created eleven orphaned laboratory nests of Atta cephalotes, A. sexdens, and A. colombica, and maintained them for 3–6 months after queen loss. Eight colonies did not produce any brood, but three nests produced 1–4 worker-derived male larvae and pupae. Microsatellite genotyping indicated that these were worker sons. However, all males were tiny (3.5–9 mm long) compared to normal queen sons (16 mm long), and would almost certainly be unable to mate. We also found reproductive eggs, but most of these had no yolk and were thus inviable. We conclude that Atta workers are not completely infertile, but that worker fertility is low compared to the sister genus Acromyrmex, where workers routinely produce normally-size males after queen loss in the laboratory. We hypothesize that worker reproduction in orphaned Atta field colonies is almost never successful because the last workers die before their sons can be raised to adulthood, but that the importance of worker-laid trophic eggs for queen feeding has precluded the evolutionary loss of worker ovaries. Received 17 January 2005; revised 12 September 2005; accepted 3 October 2005.     

Evaluation of MALDI-TOF mass spectroscopy methods for determination of Escherichia coli pathotypes

It is rapidly becoming apparent that many E. coli pathotypes cause a considerable burden of human disease. Surveillance of these organisms is difficult because there are few or no simple, rapid methods for detecting and differentiating the different pathotypes. MALDI-TOF mass spectroscopy has recently been rapidly and enthusiastically adopted by many clinical laboratories as a diagnostic method because of its high throughput, relatively low cost, and adaptability to the laboratory workflow. To determine whether the method could be adapted for E. coli pathotype differentiation the Bruker Biotyper methodology and a second methodology adapted from the scientific literature were tested on isolates representing eight distinct pathotypes and two other groups of E. coli. A total of 136 isolates was used for this study. Results confirmed that the Bruker Biotyper methodology that included extraction of proteins from bacterial cells was capable of identifying E. coli isolates from all pathotypes to the species level and, furthermore, that the Bruker extraction and MALDI-TOF MS with the evaluation criteria developed in this work was effective for differentiating most pathotypes.     

Continuous Growth and Differentiation of Trypanosoma (Megatrypanum) freitasi Rego, Magalhaes & Siqueira, 1957, In Vitro

Trypanosoma (Megatrypanum) freitasi, a parasite of didelphid opossum, was known to be very difficult to cultivate in conventional media. Co-cultivation with L929 cell line in Baltz's medium at 27.5° C resulted in luxuriant growth of the trypanosome with the production of epimastigote colonies that adhered to the surface of culture flasks or tubes, and transformation into metacylics. Further transformation was stimulated by raising the incubation temperature. At 37° C the population was of the bloodstream type and resistant to lysis by complement.     

Characterization of the cyanobacteria and associated bacterial community from an ephemeral wetland in New Zealand

New Zealand ephemeral wetlands are ecologically important, containing up to 12% of threatened native plant species and frequently exhibiting conspicuous cyanobacterial growth. In such environments, cyanobacteria and associated heterotrophs can influence primary production and nutrient cycling. Wetland communities, including bacteria, can be altered by increased nitrate and phosphate due to agricultural practices. We have characterized cyanobacteria from the Wairepo Kettleholes Conservation Area and their associated bacteria. Use of 16S rRNA amplicon sequencing identified several operational taxonomic units (OTUs) representing filamentous heterocystous and non‐heterocystous cyanobacterial taxa. One Nostoc OTU that formed macroscopic colonies dominated the cyanobacterial community. A diverse bacterial community was associated with the Nostoc colonies, including a core microbiome of 39 OTUs. Identity of the core microbiome associated with macroscopic Nostoc colonies was not changed by the addition of nutrients. One OTU was highly represented in all Nostoc colonies (27.6%–42.6% of reads) and phylogenetic analyses identified this OTU as belonging to the genus Sphingomonas. Scanning electron microscopy showed the absence of heterotrophic bacteria within the Nostoc colony but revealed a diverse community associated with the colonies on the external surface.     

The effects of simulated and natural rainfall on cochineal insects (Homoptera: Dactylopiidae): colony distribution and survival on cactus cladodes

ABSTRACT. 1. The distribution of Dactylopius opuntiae (Cockerell) colonies on Opuntia ficus-indica (L.) Miller cladodes collected during a prolonged drought, was recorded for the proximal and distal portions of the cladodes, for the exposed and sheltered surfaces, the edges, and in relation to the proximity of the colonies to areoles at the base of the thorns.
2. Most of the colonies were found on the more sheltered parts of the cladodes and a disproportionately large number of the colonies on exposed surfaces had settled below the areoles.
3. Individuals in colonies on the exposed surfaces were all protected by a relatively hard, compacted wax cover and were thus less vulnerable to simulated rainfall than those on sheltered surfaces. Thorns provided some protection from simulated rainfall for individuals in colonies on exposed surfaces, but not for individuals on sheltered surfaces.
4. Natural rainfall greatly reduced the numbers of colonies, but did not significantly change the distribution of the colonies on the cactus cladodes.
5. Rainfall does not explain the observed distribution of D. opuntiae colonies on the cladodes, but does explain the poor performance of cochineal insects as biological control agents of prickly pear cacti in high rainfall areas.