The effect of cold storage at 4 °C on the Rooting of chestnut cuttings

This article reports the effect of cold storage at 4 °C from December to April on chestnut cuttings. Rooting was found to increase after four months preceded by treatment with 4000 mg l^-1 IBA. ThePhaseolus test of the biological activity of extracts of the cuttings showed the inhibition exerted by the acid fraction of the fresh (December) cuttings to have been replaced by a rootpromoting effect in cuttings stored for 4 months at low temperature. Cold storage thus seems to favour rooting.     

The effect of aging on brain barriers and the consequences for Alzheimer’s disease development

Life expectancy has increased in most developed countries, which has led to an increase in the proportion of elderly people in the world’s population. However, this increase in life expectancy is not accompanied by a lengthening of the health span since aging is characterized with progressive deterioration in cellular and organ functions. The brain is particularly vulnerable to disease, and this is reflected in the onset of age-related neurodegenerative diseases such as Alzheimer’s disease. Research shows that dysfunction of two barriers in the central nervous system (CNS), the blood–brain barrier (BBB) and the blood–cerebrospinal fluid (CSF) barrier (BCSFB), plays an important role in the progression of these neurodegenerative diseases. The BBB is formed by the endothelial cells of the blood capillaries, whereas the BCSFB is formed by the epithelial cells of the choroid plexus (CP), both of which are affected during aging. Here, we give an overview of how these barriers undergo changes during aging and in Alzheimer’s disease, thereby disturbing brain homeostasis. Studying these changes is needed in order to gain a better understanding of the mechanisms of aging at the brain barriers, which might lead to the development of new therapies to lengthen the health span (including mental health) and reduce the chances of developing Alzheimer’s disease.     

Effect of temperature,relative humidity and aphid developmental stage on the efficacy of the mycoinsecticide Mycotal® against Myzus persicae

The green peach aphid, Myzus persicae, is a major pest worldwide. An examination of the impact of temperature, relative humidity (RH) and developmental stages of M. persicae on the efficacy of the whitefly mycoinsecticide Mycotal®, based on Lecanicillium muscarium and the effects of infection on aphid fecundity was evaluated under controlled conditions. Although this fungus can be grown at a broad range of temperatures (15–30°C), the optimum temperature for control of M. persicae ranged between 20 and 30°C. L. muscarium had high efficacy as a microbial control agent against M. persicae between 55% and 90% RH. Total mortality of aphids treated with different spore dosages of L. muscarium varied according to the developmental stage: adults, fourth and third instar nymphs proved more susceptible than first instar nymphs. Although the fungus did not affect the rate of nymph production, the reproductive period of aphids significantly decreased with increasing the spore dosage. Thus, total fecundity of treated aphids was 22.6 ± 1.1 and 31.6 ± 2.4 offspring per adult at the medium (644 ± viable spore/mm²) and low (330 ± 40 viable spore/mm²) dosages, compared with 45.7 ± 4.3 offspring per untreated aphid. The results suggest that L. muscarium has the potential as a biological control agent of M. persicae.     

Determination of phylogenetic position of Pipizini (Diptera: Syrphidae): based on molecular biological and morphological data

Based on the sequence analysis of 5.8S subunit and internal transcribed spacers (ITS ) of ribosomal RNA gene (rDNA), the molecular phylogenetic tree of representative species of Pipizini and three groups of Syrphidae with different feeding habits (seven species belong to six genera) was constructed. Meanwhile, the phylogenetic tree of tribes (including Pipizini and other 17 tribes of Syrphidae) was constructed using morphological characteristics of adults and larvae and the number of chromosomes. Both the results show that the relationship between Pipizini and predatory groups is closer than that between Pipizini and saprophagous groups. So it is suggested that Pipizini be transferred from Milesiinae to Syrphinae.     

The effect of temperature on the development,reproduction, and longevity of two common cyclopoid copepods — Eucyclops serrulatus (Fischer) and Cyclops strenuus (Fischer)

The embryonic and postembryonic development times, time interval between clutches, and longevity of two common cyclopoid copepods — Eucyclops serrulatus and Cyclops strenuus — were studied at constant temperatures (5°, 10°, 15°, 20° and 25 °C), using algae and protozoans as food. Both, E. serrulatus and C. strenuus showed a considerable temperature tolerance and adaptability. Embryonic development times were similar in both species but postembryonic development times were shorter in E. serrulatus. Time intervals between successive clutches were relatively variable at all temperatures in both species. Longevity was shorter in E. serrulatus than in C. strenuus. The embryonic and postembryonic development of E. serrulatus was short relative to that of littoral copepods; the development of C. strenuus was similar or shorter than that of other species of the genus Cyclops.     

The effect of low temperature (5–29 °C) and adaptation on the methanogenic activity of biomass

The influence of low temperature (5–29 °C) on the methanogenic activity of non-adapted digested sewage sludge and on temperature/leachate-adapted biomass was assayed by using municipal landfill leachate, intermediates of anaerobic degradation (propionate) and methane precursors (acetate, H₂/CO₂) as substrates. The temperature dependence of methanogenic activity could be described by Arrhenius-derived models. However, both substrate and adaptation affected the temperature dependence. The adaptation of biomass in a leachate-fed upflow anaerobic sludge-blanket reactor at approximately 20 °C for 4 months resulted in a sevenfold and fivefold increase of methanogenic activity at 11 °C and 22 °C respectively. Both acetate and H₂/CO₂ were methanized even at 5 °C. At 22 °C, methanogenic activities (acetate 4.8–84 mM) were 1.6–5.2 times higher than those at 11 °C. The half-velocity constant (K _s) of acetate utilization at 11 °C was one-third of that at 22 °C while a similar K _i was obtained at both temperatures. With propionate (1.1–5.5 mM) as substrate, meth‐anogenic activities at 11 °C were half those at 22 °C. Furthermore, the residual concentration of the substrates was not dependent on temperature. The results suggest that the adaptation of biomass enables the achievement of a high treatment capacity in the anaerobic process even under psychrophilic conditions. Received: 23 December 1996 / Received last revision: 18 June 1997 / Accepted: 23 June 1997     

The effect of mono‐amino acids on larval settlement of the barnacle,Balanus amphitrite Darwin

Settlement of barnacle larvae is believed to be induced by the chemical cues present in their surrounding environment. Here, an investigation was carried out on the effects of sixteen different mono‐amino acids with acidic, basic, uncharged polar and nonpolar side chains, and GABA on larval settlement of the barnacle, Balanus amphitrite. Settlement inducing activity by nine mono‐amino acids, viz. asparagine, glutamine, tyrosine, serine, glycine, tryptophan, leucine, isoleucine and valine (but not phenylalanine) with uncharged polar and nonpolar side chains was observed. Of these, the most active mono‐amino acids were serine, leucine and isoleucine, which were effective at a threshhold of 1.0 × 10^‐7 M. On the other hand, aspartic acid, glutamic acid, GABA, and the basic mono‐amino acids lysine, arginine and histidine did not have any inducing effect. These results suggest that uncharged polar and non‐polar end group of the amino acid chain play an important role in inducing the settlement process in cyprids.     

The effect of sulfate reduction on the thermophilic (55°C) methane fermentation process

Summary The continuously operated suspended growth anaerobic contact system was utilized to estimate the effect of sulfate reduction on the thermophilic (55°C) methane fermentation process. Results indicated that reduction in methanogenesis in the presence of sulfate was due to two separate, but related, processes;i.e. competitive and sulfide inhibition. Although prevention of competitive inhibition would be difficult under normal fermenter operation, sulfide inhibition could be minimized by environmental selection of sulfide tolerant microbial populations through biomass recycle and pH control. Stable fermenter operation was achieved at soluble sulfide concentrations as high as 330 mg/l soluble sulfide. Using batch fermenters, a maximum thermophilic sulfate reduction rate of 3.7 mg SO₄ ^2––S/g volatile solids (VS)-day was estimated. The importance of reporting sulfate reduction rates on a biomass basis is demonstrated by a simple population adjustment kinetic model.This research study was conducted at the Department of Agricultural Engineering, Cornell University, Riley Robb Hall, Ithaca, NY 14853, U.S.A.     

The effect of some ions on the activity of β-galactosidase and the inhibitory effect of tris (hydroxymethyl) aminomethane

The stimulating effect of phosphate and the inhibitory effect of tris-HCl on the activity of β-galactosidase inEscherichia coli was studied. The phosphate anion antagonizes the inhibitory effect of chloride. Since a similar effect is displayed by sulphate and arsenate no specific “stimulating” effect of phosphate can take place. The tris cation has also an inhibitory effect which is antagonized by univalent cations (K⁺). The resulting β-galactosidase activity reflects the antagonisms between cations and anions present in the reaction medium.     

Effects of temperature on egg and larval survival of cod (Gadus morhua) and sprat (Sprattus sprattus) in the Baltic Sea – implications for stock development

Hydrobiologia - Stock development of cod and sprat, two major fish species in the Baltic Sea, is linked by trophic interactions. Depending on recruitment success the Baltic may be pushed towards...     

The effect of melatonin on the quality of extended boar semen after long-term storage at 17 °C

Melatonin (MLT) is an efficient antioxidant that protects cells and tissues and initiates a host of receptor-mediated effects. In order to enhance the life span of refrigerated boar semen, our aim was to evaluate the effects of addition of 1 μM MLT to commercially produced pig semen (33 seminal doses from 14 boars) that had been preserved at 17 °C for 7 days. Samples without MLT served as controls. On Days 1, 4 and 7, we evaluated motility parameters and the percentage of total motile and progressively motile spermatozoa by a computer-aided sperm analysis system. Viability (SYBR-14/PI), acrosomal status (FITC-PNA/PI), membrane fluidity (M-540/YoPro-1) and mitochondrial membrane potential status (JC-1) were evaluated by flow cytometry. MLT treatment significantly enhanced the percentage of static spermatozoa after 7 days of storage and significantly reduced the percentage of progressively motile spermatozoa on Day 7. The velocity characteristics (VCL, VSL and VAP) were significantly higher for MLT-treated samples on Day 1 and were their lowest on Day 7. With regard to flow cytometry results, the percentage of viable spermatozoa with an intact acrosome was higher in MLT samples throughout the entire storage period. In addition, there was a significantly higher proportion of live spermatozoa on Day 7 in the samples that had not been treated with MLT. The proportion of spermatozoa showing a high mitochondrial membrane potential remained at similar levels (P > 0.05) throughout the trial. Although the findings of the present study revealed that 1 μM MLT increased the proportion of live sperm with an intact acrosome, this treatment did not enhance the spermatic quality of refrigerated boar semen.     

The “dehesa”, a key ecosystem in maintaining the diversity of Mediterranean saproxylic insects (Coleoptera and Diptera: Syrphidae)

The “dehesa” is a traditional Iberian agrosilvopastoral ecosystem characterized by the presence of old scattered trees that are considered as “keystone-structures”, which favor the presence of a wide range of biodiversity. We show the high diversity of saproxylic beetles and syrphids (Diptera) in this ecosystem, including red-listed species. We analyzed whether saproxylic species distribution in the “dehesa” was affected by tree density per hectare, dominant tree species or vegetation coverage. Species diversity did not correlate with tree density; however, it was affected by tree species and shrub coverage but in a different way for each taxon. The highest beetle diversity was linked to Quercus pyrenaica, the most managed tree species, with eight indicator species. In contrast, Q. rotundifolia hosted more species of saproxylic syrphids. Regarding vegetation coverage, shrub coverage was the only variable that affected insect richness, again in a different way for both taxa. In contrast, beetle species composition was only affected by dominant tree species whereas syrphid species composition was not affected by tree species or shrub coverage. We concluded that the high diversity of saproxylic insects in the “dehesa” is related to its long history of agrosilvopastoral management, which has generated landscape heterogeneity and preserved old mature trees. However, the richness and composition of different taxa of insects respond in different ways to tree species and vegetation coverage. Consequently, conservation strategies should try to maintain traditional management, and different saproxylic taxa should be used to monitor the effect of management on saproxylic diversity.     

The effect of prostaglandin F(2α) administration at the time of insemination on the pregnancy rate of dairy cows

This paper addresses the question whether the pregnancy rate of dairy cows and heifers may be affected by administering prostaglandin F_2α at the time of artificial insemination. A field trial involving 1031 dairy cows and heifers distributed to a large number of small dairy farms in an area of extensive farming in central Germany provided evidence that intramuscular administration of 25 mg Dinoprost (Dinolytic^®) at the time of insemination has no effect on pregnancy rate (61% of the cows and heifers were pregnant in both prostaglandin F_2α-treated and saline control groups). On the other hand, deposition of 0.5 mL of a 0.5 mg/mL Dinoprost solution in the uterine lumen immediately after artificial insemination gave rise to a pregnancy rate of 66% as compared with 59% in saline controls. The increase in pregnancy rate of 229 prostaglandin F_2α-treated animals (66% pregnant) over that of 226 saline controls (59% pregnant) amounted to 12%. This improvement was not statistically significant (P = 0.12). Factors exerting a significant effect on pregnancy rate were parity (74% pregnancies in heifers versus 57% in cows, P < 0.01 and 65% pregnancies in first parity-cows versus 55% in older cows, P < 0.01) and season (57% during the barn season versus 64% during the pasture season, P < 0.05), whereas length of service period, level of milk production and serum or milk progesterone level at the time of insemination did not. A follow-up trial involving more animals will have to be conducted aimed at confirming the promising results obtained by intrauterine PGF_2α administration.     

The effect of inspiratory and expiratory loads on abdominal muscle activity during breathing in subjects “at risk” for the development of chronic obstructive pulmonary disease and healthy

The abdominal muscle activity has been shown to be variable in subjects with chronic obstructive pulmonary disease (COPD) when respiratory demand increases and their recruitment pattern may change the mechanics, as well as the work and cost of breathing. The scientific evidence in subjects “at risk” for the development of COPD may be important to understand the natural history of this disease. This study aims to evaluate the effect of inspiratory and expiratory loads on the abdominal muscle activity during breathing in subjects “at risk” for the development of COPD and healthy. Thirty-one volunteers, divided in “At Risk” for COPD (n = 17; 47.71 ± 5.11 years) and Healthy (n = 14; 48.21 ± 6.87 years) groups, breathed at the same rhythm without load and with 10% of the maximal inspiratory or expiratory pressures, in standing. Surface electromyography was performed to assess the activation intensity of rectus abdominis (RA), external oblique and transversus abdominis/internal oblique (TrA/IO) muscles, during inspiration and expiration. During inspiration, in “At Risk” for COPD group, RA muscle activation was higher with loaded expiration (p = 0.016); however, in Healthy group it was observed a higher activation of external oblique and TrA/IO muscles (p < 0.050). During expiration, while in “At Risk” for COPD group, RA muscle activation was higher with loaded inspiration (p = 0.009), in Healthy group TrA/IO muscle showed a higher activation (p = 0.025). Subjects “at risk” for the development of COPD seemed to have a specific recruitment of the superficial layer of ventrolateral abdominal wall for the mechanics of breathing.     

The effect of food concentration on the gut clearance time of Pseudocalanus minutus Krøyer (Calanoida: Copepoda)

The effect of food concentration on gut clearance time of a pelagic copepod, Pseudocalanus minutus Krøyer, was investigated. Gut clearance time was estimated from ingestion rate and gut content pigment of copepods which were continuously fed during experiments. The time estimated by this method was longer than that estimated by evacuation of gut content pigment in filtered sea water by a factor of 1.3 to 2.6. Gut clearance time showed fluctuation with food concentration over 1.6 to 3.3. h, whereas food category had little effect on the time.     

The effect of ice formation on the function of smooth muscle tissue stored at −21 or −60 °C

The mechanisms by which single cells are injured during freezing are relatively well understood, but it is likely that additional factors apply to tissues and organs, factors that may be responsible for the poor suecess of attempts to cryopreserve complex multicellular systems. One such factor may be the formation of extracellular ice.

This study was designed to discover whether ice formation as such is detrimental to the contractile recovery of pieces of mammalian smooth muscle after storage at subzero temperatures. Strips of taenia coli muscle were equilibrated with 2.56 M Me₂SO in a buffered solution, cooled at either 0.3 or 2 °C/min to ?21 °C and then held at this temperature in the frozen state. Other muscle strips were bathed in a solution the composition of which mimicked that of the unfrozen phase of the previous solution at ?21 °C; it contained 4.49 M Me₂SO and 1.75 times the normal concentration of salts, and muscles equilibrated with this solution were also cooled at either 0.3 or 2 °C/min to ?21 °C, and then held unfrozen for the same length of time.It was shown that exposure to ?21 °C and the increased concentration of solutes had little effect on the contractile recovery of the muscles, whereas ice formation was damaging. Furthermore, the rate of cooling had a marked effect upon functional recovery in the frozen muscles, and this could be correlated with the known effect of these cooling rates on the pattern of ice formation in the tissue. The effect was also seen in muscles frozen at ?60 °C. Improved buffering increased the functional recovery of all groups, but the effect of ice, and of cooling rate in the presence of ice, was confirmed. These findings may have significant implications for attempts to cryopreserve complex tissues and organs.     

The muscular system of the ovipositor of Spaziphora hydromyzina (Fallén) (Diptera, Scathophagidae)

The structure of the ovipositor sclerites and muscles was investigated in Spaziphora hydromyzina (Diptera, Scathophagidae).     

Checklist of the families Lonchopteridae and Phoridae?of Finland (Insecta,Diptera)

A checklist of the Lonchopteridae and Phoridae recorded from Finland is presented.