The effects of light quality on the growth of phototrophic bacteria in lakes

The effects of light quality (color) on the ¹⁴CO₂ fixation rates of natural population of photosynthetic sulfur bacteria were tested. The phototrophic bacteria were collected from the sulfide containing waters of 3 stratified lakes. The populations sampled survive in environments where light intensities are very low. Not only are the light intensities low but, due to the light filtering characteristics of the lake water, the light is of specific color. It was determined that the spectral properties of the three lakes differed, hence the quality of light reaching the phototrophic bacteria in each lake differed. It was also observed that only green sulfur bacteria were present in the study lake which transmits mainly red light and both purple and green sulfur bacteria were present in the two study lakes which transmit predominantly green light. Enrichment cultures were set up with phototrophic bacteria from two of the lakes serving as the inocula. Enrichment culture studies and photosynthetic responses of the natural populations indicate that light quality is a major factor in determining the composition of phototrophic bacterial population in some lakes.Non-Common Abbreviations Bchl Bacteriochlorophyll - DPM Disintegrations per minute     

Loss of genetic variation in laboratory colonies of Phormia regina

Genetic variation of laboratory and wild Phormia regina was examined by gel electrophoresis of enzymes. The two old laboratory stocks studied possessed much less genetic variation than wild flies.

---

Zusammenfassung Die genetische Variabilität in Kulturen von Laboratoriumstämmen oder wilden Fliegen von Phormia regina wurde mittels Gel Elektrophoresis von 6 Enzymen studiert. Vier verschiedene Stämme wurden untersucht: wilde Fliegen, die F₁ Nachkommen der wilden Fliegen, ein rot-äugiger und ein weiss-äugiger Laboratoriumstamm. Die wilden Fliegen waren genetisch sehr variabel (mittlere Heterozygosität = 0.157). Die geringste Variabilität war in den weiss-äugigen Fliegen (mittlere Heterozygosität = 0.009). Die Laboratoriumstämme sind genetisch dem wilden Fliegenmaterial nicht ähnlich.

     

The influence of substrate organic content on the growth of a stream chironomid

Stream detritus and Tipula (Diptera) feces were wet-sieved to a 63–250 µm particle size range and mixed in three proportions with ashed sand of the same size to yield food substrates of varying quality. Growth of fourth-instar Stictochironomus annulicrus (Townes) (Diptera: Chironomidae) larvae was used to indicate whether the more nutritious particles were selected from these mixtures. Respective mean relative growth rates on the substrates, in order of decreasing percentage organic matter (i.e. food quality), were: 0.0229, 0.0104 and 0.0004 mg·mg^–1d^–1. Replicates of the relatively high quality substrate consistently elicited the highest growth rates; animals grew at intermediate rates on medium quality, and slowest on low quality substrates. Thus, this collector does not appear to have selected for food quality under the described experimental conditions.     

The impact of surface mine reclamation on headwater streams in Southwest Virginia

Recovery of headwater streams following the cessation of mining and the application of terrestrial (vegetative) reclamation techniques was assessed by comparison of water quality and aquatic biota in two such systems (reclaimed four to seven years) with that of an unimpacted stream and of streams draining mine areas which were abandoned without reclamation. Alkalinity, hardness, sulfate, and conductivity were elevated in the reclaimed mine streams as were fine-particle suspended solids and sediment. Overall water quality was comparable to streams draining unreclaimed lands. Benthic invertebrate and fish populations were significantly lower in abundance in the reclaimed mine streams than in the reference stream and showed less taxonomic richness and stability; they were similar in these respects to the biota of the unreclaimed mine streams. Continued sedimentation from mined areas and haul roads affected stream habitat and appeared to be the major factor limiting biotic recovery. These findings emphasize that terrestrial reclamation does not assure lotic restoration. Water quality criteria merit consideration in the refinement of reclamation procedures for mined lands.     

Effect of thermal stress on fertility and egg quality of Japanese quail

Heat stress is one of the major causes of a decreased performance of laying quail in tropical and subtropical countries. The aim of this study was to investigate the impact of temperature humidity index (THI) on fertility aspects, external and internal egg quality parameters in Japanese quail. One hundred and forty four (144) Japanese quail, 12 of weeks age, were used. Birds were divided randomly into three equal groups, control (at low THI, lower than 70), H₁ (at moderate THI, 70–75) and H₂ (at high THI, 76–80). Quail in the control and H₁ groups had significant greater fertility (p=0.021) and hatchability % (p=0.037), compared with H₂ group. Quail in the control group (at low THI) laid heavier egg weight with a higher external (egg weight (p=0.03), shell thickness, shell weight, eggshell ratio and eggshell density (p=0.001)) and internal egg quality score (albumin weight (p=0.026), yolk height (p=0.003), yolk index (p=0.039) and Haugh unit (p=0.001)). Otherwise, such quality traits were compromised in heat-stressed quail. At the high THI level, egg weight had a significant positive correlation with albumin weight (r=0.58, p<0.01), yolk weight (r=0.22, p<0.05), albumen ratio (r=0.17, p<0.05), yolk height (r=0.14, p<0.05) and yolk index (r=0.18, p<0.05), but was negatively correlated with yolk ratio (r=−0.15, p<0.05). Japanese quail exposed to heat stress (THI over 75) revealed drop in fertility indices and egg quality traits, indicating a detrimental policy of economic income.     

Effects of feeding transgenic corn with mCry1Ac or maroACC gene to laying hens for 12 weeks on growth,egg quality and organ health

The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn–soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar to that of laying hens fed diets formulated with the non-transgenic near-isoline corn with comparable genetic backgrounds.     

The effect of internal capacitance on power quality and energy efficiency in a tubular microbial fuel cell

The pseudo-capacitive behaviour of a high surface area carbon veil electrode in a tubular microbial fuel cell (MFC) was investigated as a mechanism to enhance power quality and energy efficiency. Accumulated charge and energy from the anodic biofilm after prolonged open circuit times (1–120 min) were compared against equivalent periods of steady state loading (R = 100–3000 Ω). A significant difference in the amount of accumulated charge with different loads was observed, resulting in 1.051 C (R = 100 Ω) compared to 0.006 C (R = 3 kΩ). The automated application of short open and closed circuit (0.5–10 s) cycles resulted in an increase of power/current production (closed circuit alone), but presented lower efficiency considering entire open and closed period. The cumulative charge on the carbon veil electrode with biofilm was 39,807 C m⁻² at 100 Ω. Electrochemical Impedance Spectroscopy (EIS) showed that the Helmholtz layer presented a double layer capacitance of more than ten times the biofilm on electrode. The results indicate that the capacitive behaviour could be utilized to increase the power quality, i.e. its availability/applicability with respect to the operation of low power consuming devices.     

Yeasts and yeast-like fungi in tap water and groundwater,and their transmission to household appliances

In the present study we describe the occurrence of fungi in 100 tap water and 16 groundwater samples from Slovenia. We used culture-dependent and culture-independent techniques. 28 fungal species belonging to 16 genera were isolated with selected culturing conditions, targeting human opportunistic yeasts and yeast-like fungi. Of special concern was the detection of Aureobasidium melanogenum, Exophiala dermatitidis, Rhinocladiella similis, Candida parapsilosis and Rhodotorula mucilaginosa. The DGGE analysis of ITS1 rDNA revealed from 6 to 16 bands hypothetically corresponding to different taxa, while pyrosequencing showed the presence of Aspergillus and Exophiala. According to the statistic machine learning methodology, the profile of fungi in water is determined by the concentration of calcium and magnesium ions and the presence of nitrate. Exophiala spp., C. parapsilosis and R. mucilaginosa are known as dominant contaminants of household appliances. It appears that they are transferred with water to dishwashers and washing machines, where they subsequently proliferate.     

News from the Biological Stain Commission No. 12

Abstract

In this 12^th issue of News from the Biological Stain Commission (BSC) under the heading of Regulatory affairs, the Biological Stain Commission’s International Affairs Committee presents information from the meetings of ISO/TC 212/WG 1 Quality and competence in the medical laboratory and ISO/TC 212/WG 3 In vitro diagnostic products both held on 2 – 3 June 2010, plus information on the second plenary meeting of ISO/TC 212 Clinical laboratory testing and in vitro diagnostic test systems held on 4 June 2010. All meetings took place in Seoul, Republic of Korea. Finally, information is provided concerning the 25^th meeting of CEN/TC 140 In vitro diagnostic medical devices held on 23 June 2010 in Berlin, Germany.