Hypoglycemic effects of exopolysaccharides produced by mycelial cultures of two different mushrooms Tremella fuciformis and Phellinus baumii in ob/ob mice

The anti-diabetic activities of the exopolysaccharides (EPS) produced by submerged mycelial culture of two different mushrooms, Tremella fuciformis and Phellinus baumii, in ob/ob mice were investigated. All the animals were randomly divided into three groups with seven animals in each group: The control group received 0.9% NaCl solution; the diabetic groups were treated with EPS from T. fuciformis (Tf EPS) and P. baumii (Pb EPS) at the level of 200 mg/kg body weight using an oral zoned daily for 52 days. The plasma glucose levels in the EPS-fed mice were substantially reduced by about 52% (Tf EPS) and 32% (Pb EPS), respectively, as compared to control mice. The results of oral glucose tolerance test (OGTT) revealed that both EPS-fed groups significantly increased the glucose disposal after 52 days of EPS treatments. Furthermore, higher food efficiency ratios and reduced blood triglyceride levels were observed in the EPS-treated groups. Because peroxisome proliferator-activated receptor gamma (PPAR-γ) is indeed a key regulator of insulin action, we investigated the expression pattern of adipose tissue PPAR-γ messenger RNA (mRNA) and plasma levels of PPAR-γ. It was revealed that PPAR-γ was significantly activated in response to EPS treatments. The results suggested that both EPS exhibited considerable hypoglycemic effect and improved insulin sensitivity possibly through regulating PPAR-γ-mediated lipid metabolism. Our results indicated that two mushroom-derived EPS might be developed as potential oral hypoglycemic agents or functional foods for the management of non-insulin-dependent diabetes mellitus.     

Genotyping of Trichophyton rubrum by analysis of ribosomal-DNA intergenic spacer regions

An attempt was made to explore the genotyping of Trichophyton rubrum (T. rubrum) and the relationship between genotype and geographical origin using ribosomal restriction endonuclease polymorphic analysis. The total DNA was extracted by cetyltrimethyl ammonium bromide (CTAB). The probe was amplified from part of the 18S, ITSI, 5.8S, and ITSII region of T. rubrum standard strain with the universal fungal primers NS5 [5′-AACTT AAAGG AATTG ACGGA AG-3′] and ITS4 [5′-TCCTC CGCTT ATTGA TATGC-3′]. The genomic DNA of 49 clinical T. rubrum isolates digested by EcoR1 were hybridized with this probe, and the hybridization patterns were used as the basis of genotyping. Of the data from 49 strains of T. rubrum studied (21 from Nanjing, 26 from Dalian, and two from Beijing), 20 individual patterns (DNA Type A–T) were identified, among which Type A–C accounted for 48.98% of all the strains. The DNA patterns of Nanjing strains were represented by three bands, those of Dalian strains were represented by four bands. The DNA typing of T. rubrum by Southern blotting was highly sensitive and highly distinguishable. The DNA patterns of Nanjing strains were obviously different from those of Dalian strains.     

Effect of antimicrobial activity of Melaleuca alternifolia essential oil on antagonistic potential of Pleurotus species against Trichoderma harzianum in dual culture

Melaleuca alternifolia (tea tree) essential oil was investigated for its “in vitro” ability to control Trichoderma harzianum, a fungal contaminant that causes extensive losses in the cultivation of Pleurotus species. The antifungal activity of M. alternifolia essential oil and antagonist activities between Pleurotus species against three T. harzianum strains were studied in dual-culture experiments on an agar-based medium in which different concentrations of essential oil were incorporated. M. alternifolia essential oil at a concentration of 0.625 μL/mL, inhibited T. harzianum mycelial growth by 5.9–9.0%, depending on the strain. At the same concentrations P. ferulae and P. nebrodensis stimulated mycelial growth by 5.2–8.1%. All strains of T. harzianum were antagonistic to the Pleurotus species in the control. When essential oil was added to the substrate cultural, the antagonistic activity of T. harzianum against the Pleurotus species was weak (0.0625 μL of essential oil) or non-existent (0.125 μL of essential oil). M. alternifolia essential oil could be an alternative to the synthetic chemicals that are currently used to prevent and control T. harzianum in mushroom cultivation.     

Effects of leguminous ground cover competition on red birch and soil nutrient status in the nursery

Legumes as ground cover are regularly planted to increase nitrogen economy of crops and to improve soil. In the present study various clover species were evaluated as vegetative ground cover in nursery field production of micropropagated red birch (Betula pubescensEhrh. f. rubraUlvinen f. nova) in two 2-year experiments. The clover species and cultivars, Trifolium pratenseL. ‘Bjursele’, T. repens L. ‘Jogeva’, T. repens L. ‘Sonja’, T. hybridum L. ‘Frida’, T. incarnatum L. ‘Opolska’, T. resupinatum L. and T. subterraneum L. were compared to grass sod Festuca rubra L. ‘Ensylva’ and to a coverless ground (control). The last one was kept weed free by hand hoeing. Birch (leaves, stems, branches and roots) and soil nutrient concentrations (N, P, K, Ca, Mg and Fe) were analysed and nutrient ratios in birch determined. The annual clovers, T. incarnatumL., T. resupinatumL. and T. subterraneumL., provided about the same nutrient status in birch as did the control. Perennial clovers and grass were strong competitors with trees. High levels of P and Mg in birch leaves relative to N concentration were typical for poorly growing seedlings. Neither annual nor perennial clovers did generally improve soil nutrient status. This revised version was published online in June 2006 with corrections to the Cover Date.     

Revision of the Endemic Hawaiian genus <Emphasis Type="Italic">Trematolobelia</Emphasis> (Campanulaceae: Lobelioideae)

Trematolobelia (Campanulaceae: Lobeliodeae) is a genus of semelparous pliestesial pachycaul rosette treelets endemic to the Hawaiian Islands. Eight species are re-cognized. The most widespread is T. macrostachys, found in the Ko‘olau Mountains of O‘ahu and on Moloka‘i and Maui. The remainder are single-island endemics: T. auriculata (Lna‘i); T. grandiflora (Hawai‘i); T. kaalae, comb. et stat. nov. (Wai‘anae Mountains of O‘ahu); T. kauaiensis (Kaua‘i); T. rockii (Moloka‘i); T. singularis (Ko‘olau Mountains of O‘ahu); and T. wimmeri (Hawai‘i).     

An investigation on the polymorphisms of two DNA repair genes and susceptibility to ESCC and GCA of high-incidence region in northern China

Aim To investigate the possible association of three SNPs, XRCC2 C41657T, XRCC2 G4234C and XRCC3 A17893G with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) in a population of northern China. Methods XRCC2 C41657T, XRCC2 G4234C and XRCC3 A17893G SNP were genotyped by polymerase-chain reaction (PCR)–restriction fragment length polymorphism (RFLP) analysis in 583 cancer patients (329 ESCC and 254 GCA) and 614 healthy controls. Results The genotype distribution of the XRCC2 C41657T in ESCC and GCA patients were significantly different from that in healthy controls (P values = 0.04 and 0.04 respectively). And a significant difference was found in the allele distribution of GCA patients from that in controls (P = 0.01). The XRCC2 C41657T polymorphism was associated with a modest enhancement in ESCC risk and GCA risk: OR for C/T genotype was 1.38 (1.01–1.89) in GCA risk and for T/T genotype was 2.24 (1.10–4.57) in ESCC risk. When stratified for age, smoking status and family history of UGIC, the C/T genotype showed a modest significant trend on the risk of GCA patients in the groups of age ≤50 years and non-smokers, the adjusted OR were 2.84 (1.21–6.66) and 1.62 (1.06–2.49). The T/T genotype significantly increased the susceptibility of GCA patients in negative family history of UGIC (3.04, 1.02–8.32) and to ESCC patients in the group of age >50 years (3.03, 1.31–6.98), Negative family of UGIC (3.03, 1.12–7.07) and smokers (2.64, 1.02–6.83). The genotype and allele distribution of XRCC2 G4234C and XRCC3 A17893G in ESCC and GCA patients were not significantly different from that in healthy controls (all P values were above 0.05). Conclusion In this study, we found that the C41657T polymorphism of XRCC2 genes might modify the risk of ESCC and GCA development.     

Endocrinological investigation into the reproductive cycles of two sympatric skate species, Malacoraja senta and Amblyraja radiata, in the western Gulf of Maine

The smooth skate, Malacoraja senta, and thorny skate, Amblyraja radiata, are two commercially exploited batoids found within the Gulf of Maine. During the past five years, we conducted a large study to accurately describe important biological life history parameters previously lacking for these species. As part of that project, the current study reports our findings on the hormonal profiles associated with the reproductive cycles of M. senta and A. radiata. Blood samples were obtained from mature M. senta and A. radiata of both sexes from all months of the year, and plasma testosterone (T), estradiol (E₂) and progesterone (P₄) concentrations were determined using radioimmunoassay (RIA). In female M. senta and A. radiata, monthly T concentrations ranged from 4,522 pg ml⁻¹ to 1,373 pg ml⁻¹ and 31,940 pg ml⁻¹ to 14,428 pg ml⁻¹, E₂ concentrations from 831 pg ml⁻¹ to 60 pg ml⁻¹ and 8,515 pg ml⁻¹ to 2,902 pg ml⁻¹, and P₄ concentrations from 3,027 pg ml⁻¹ to 20 pg ml⁻¹ and 3,264 pg ml⁻¹ to 331 pg ml⁻¹, respectively. No statistical differences were detected between any months for any hormone. Estradiol concentrations were not correlated with ovary weight, shell gland weight, or diameter of the largest follicles in either species. Monthly T concentrations in male M. senta and A. radiata ranged from 23,146 to 12,660 pg ml⁻¹ and from 57,500pg ml⁻¹ to 24,737 pg ml⁻¹, while E₂ concentrations ranged from 7.5 pg ml⁻¹ to undetectable and 103 to 30 pg ml⁻¹, respectively. No statistical differences were observed between months for either steroid. Testosterone concentrations were weakly correlated with testes weight and percent of stage VI spermatocysts in A. radiata, however, no correlation was detected between T and stage VI spermatocysts in M. senta. Collectively, these data support the previous conclusion that M. senta and A. radiata of both sexes are capable of reproducing year round in the western Gulf of Maine.     

Sulcal patterns of fossilTheropithecus baboons: Phylogenetic and functional implications

Sulcal patterns were determined from endocasts of fossilTheropithecus (T. oswaldi andT. darti) and compared to the sulcal pattern of extant geladas (T. gelada). A comparison of the configurations of central and arcuate sulci suggests that the cortical motor face representation is relatively enlarged in extantTheropithecus, whereas the cortical motor and sensory face representations were enlarged inT. oswaldi. A relatively expanded sensory and/or motor cortical face representation may be related to masticatory (e.g., “seed-eating”) and gestural (e.g., “lipflip”) functions. SinceT. oswaidi is more derived (expanded) in sensory face representation thanT. gelada, it seems unlikely that it was a direct ancestor of modern geladas. Rather, the two groups were separate by 1.8 million years ago and may have had a most recent common ancestor similar toT. darti from the Hadar Formation of Ethiopia between 2 and 3 million years ago.     

Lectotypification of Cacao guianensis Aublet (Sterculiaceae)

Hitherto “suppressed,”Cacao guianensis, based on a mixture of elements that can be referred to three currently recognized species (i.e.,Theobroma cacao, T. subincanum, andT. velutinum), is lectotypified by Aublet's illustrations of its flowers. This makesC. guianensis a taxonomic synonym ofT. cacao and encourages nomenclatural stability by permitting the continued use ofT. subincanum andT. velutinum.     

Cloning and sequencing of nifBHDKENX genes of Paenibacillus massiliensis T7 and its nif promoter analysis

A 324 bp of nifH fragment was PCR amplified from Paenibacillus massiliensis T7 using the universal degenerate primers. The PCR-amplified nifH fragment was labeled with DIG and then used as a probe in Southern blot analysis. Southern blot result showed that there were two positive signals, indicating that there might be two copies of nifH in P. massiliensis T7. A total of 10254 bp DNA sequence containing purD and nifBHDKENX was obtained by five rounds of inverse-PCR amplification. The predicted proteins of nifBHDKENX had high homology with those from other nitrogen-fixing bacteria. Only one putative σ⁵⁴-dependent promoter sequence was detected upstream of the nifB gene and nifBHDKENX were likely to be organized in one operon. Assays of β-galactosidase activity of P. massiliensis T7PB carrying a nifB-lacZ fusion under different concentrations of NH⁺₄ and O₂ showed that the expression of nifB-lacZ was strongly inhibited by O₂.     

Establishment of an efficient <Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-mediated leaf disc transformation of <Emphasis Type="Italic">Thellungiella halophila</Emphasis>

Thellungiella halophila is a salt-tolerant close relative of Arabidopsis, which is adopted as a halophytic model for stress tolerance research. We established an Agrobacterium tumefaciens-mediated transformation procedure for T. halophila. Leaf explants of T. halophila were incubated with A. tumefaciens strain EHA105 containing a binary vector pCAMBIA1301 with the hpt gene as a selectable marker for hygromycin resistance and an intron-containing β-glucuronidase gene as a reporter gene. Following co-cultivation, leaf explants were cultured on selective medium containing 10 mg l⁻¹ hygromycin and 500 mg l⁻¹ cefotaxime. Hygromycin-resistant calluses were induced from the leaf explants after 3 weeks. Shoot regeneration was achieved after transferring the calluses onto fresh medium of the same composition. Finally, the shoots were rooted on half strength MS basal medium supplemented with 10 mg l⁻¹ hygromycin. Incorporation and expression of the transgenes were confirmed by PCR, Southern blot analysis and GUS histochemical assay. Using this protocol, transgenic T. halophila plants can be obtained in approximately 2 months with a high transformation frequency of 26%.     

Coexpression of Elo-like enzyme and Δ5, Δ4-desaturases derived from Thraustochytrium aureum ATCC 34304 and the production of DHA and DPA in Pichia pastoris

Thraustochytrium aureum ATCC 34304 produces a high level of polyunsaturated fatty acids (PUFAs), which are typically synthesized by strings of reactions catalyzed by desaturase and elongase enzymes. In this study, the genes related to the biosynthesis of PUFAs were investigated and targeted to enable optimization of the production of PUFAs. To the best of our knowledge, this is first study to evaluate the co-expression of genes TaElo, Tad5, and Tad4genes derived from T. aureum. We found that C22 PUFAs such as docosapentaenoic acid (DPA, C22:5n–6) and docosahexaenoic acid (DHA, 22:6n–3) were synthesized from γ-linolenic acid (GLA, C18:3n–6) and stearidonic acid (SDA, C18:4n–3), respectively, as exogenous substrates via a series of reactions catalyzed by an Elo-like enzyme and Δ5, Δ4-desaturase enzymes. In addition, the results of this study revealed that the TaElo gene could synthesize the Δ6-and Δ5-elongation products. Taken together, these results confirmed that the Elo-like enzyme was involved in multiple reactions leading to the production of PUFAs and that the TaElo, Tad5, and Tad4 genes were capable of functioning together to produce DPA and DHA using GLA and SDA.     

Kalanchoe blossfeldiana plants expressing the Arabidopsis etr1-1 allele show reduced ethylene sensitivity

Transgenic Kalanchoe blossfeldiana Poelln. with reduced ethylene sensitivity in flowers was obtained by Agrobacterium tumefaciens-mediated transformation using the plasmid pBEO210 containing the mutant ethylene receptor gene etr1-1 from Arabidopsis thaliana under the control of the flower-specific fbp1-promoter from Petunia. Three ethylene-resistent T0 lines, 300, 324 and 331, were selected and analyzed for postharvest-performance and morphological characteristics. Line 324 was found to be infertile and only slightly less ethylene-sensitive than control-plants, but lines 300 and 331 had significantly increased ethylene-resistance and were fertile. These two lines were analyzed for copy-number of the etr1-1 gene by Southern blotting and were crossed with the ethylene-sensitive cultivar ‘Celine’ to create T1 progeny. Line 300 contains two T-DNA copies per nucleus, one of which is rearranged, and these are unlinked according to segregation data from the crossing to ‘Celine’ and PCR-analysis of progeny plants. For control plants all flowers were closed after 2 days at 2 μl l⁻¹ ethylene, but for line 300 only 33% were closed after 10 days. Line 331 contains three T-DNA copies per nucleus and is more sensitive to ethylene than line 300. In the line 300 the etr1-1 gene was found by RT-PCR to be expressed in petals and stamens but not in carpels and sepals. Both lines 300 and 331, and their progeny, appear morphologically and physiologically identical to control plants except for the higher ethylene resistance. Line 300 and its progeny with only one T-DNA copy have very low ethylene sensitivity and may be useful in future breeding.     

In vitro antagonism of Thielaviopsis paradoxa by Trichoderma longibrachiatum

Seventy-nine Trichoderma strains were isolated from soil taken from 28 commercial plantations of Agave tequilana cv. ‘Azul’ in the State of Jalisco, Mexico. Nine of these isolates produced nonvolatile metabolites that completely inhibited the growth of Thielaviopsis paradoxa on potato dextrose agar plates. These isolates were identified as Trichoderma longibrachiatum on the basis of their morphology and DNA sequence analysis of two genes (ITS rDNA and translation elongation factor EF-1α). Mycoparasitism of Th. paradoxa by T. longibrachiatum strains in dual cultures was examined by scanning electron microscopy. The Trichoderma hyphae grew alongside the Th. paradoxa hyphae, but penetration of Thielaviopsis hyphae by Trichoderma was no apparent. Aleurioconidia of Th. paradoxa were parasitized by Trichoderma. Both hyphae and aleurioconidia of Th. paradoxa lost turgor pressure, wrinkled, collapsed and finally disintegrated. In liquid cultures, all nine Trichoderma isolates produced proteases, β-1,3-glucanases and chitinases that would be responsible for the degradation of Thielaviopsis hyphae. These results demonstrate that the modes of action of T. longibrachiatum involved against Th. paradoxa in vitro experiments are mycoparasitism and the production of nonvolatile toxic metabolites.     

Dermatophytes and other keratinophilic fungi from coypus (Myocastor coypus) and brown rats (Rattus norvegicus)

The occurrence of mycotic agents was investigated by hair-brush technique on the coat of 162 naturalized coypus (Myocastor coypus) and 64 indigenous brown rats (Rattus norvegicus) originating from the same protected area in Central Italy. The isolates from positive coypus (29.6%) were identified as Microsporum gypseum (14.8%), Trichophyton terrestre (9.8%), Alternaria sp. (3.7%), Trichophyton mentagrophytes (2.5%), Cladosporium sp. (1.8%), Scopulariopsis sp. (1.2%), and Chrysosporium keratinophilum (0.6%), whereas the isolates from positive rats (46.7%) were identified as M. gypseum (28.1%), T. mentagrophytes (12.5%), Chrysosporium tropicum and T. terrestre (3.1% each), and Chrysosporium inops (1.6%). Statistically, brown rats were more likely to harbor fungal agents (P < 0.05) on their coat than coypus, especially T. mentagrophytes (P < 0.01) and M. gypseum (P < 0.05). No positive animal showed dermatological lesions. The present results are the first providing basic information on the coat’s mycoflora of a wild coypu population. It is concluded that the coypu, an allochthonous rodent in Italy, can play a role as natural animal reservoir of dermatophytes and as carrier of keratinophilic and saprophytic fungi within its new habitat, though to a lesser extent than indigenous rats. Therefore, people who are exposed to the risk of contact with the coat of rats and coypus should take all the cautions needed to protect themselves from mycotic agents potentially transmissible to humans.     

The influence of natural enemies on brood production inIps typographus (Col. scolytidae) with special reference to egg-laying and predation byThanasimus formicarius (Col.: Cleridae)

The predatorThanasimus formicarius (L.) (Coleoptera, Cleridae) and its preyIps typographus (L.) (Coleoptera, Scolytidae) were studied in the laboratory and the field. In the laboratory, 11T. formicarius laid 71–132 eggs (mean=162) during 66–123 days. During this time they ate 66–132I. typographus adults per pair (male +female). The number of eggs laid per female was not correlated with life span or the number ofIps eaten. In the field, predation byT. formicarius larvae and other natural enemies onI. typographus brood was studied in the last year of an outbreak. Caged and uncaged spruce bolts attacked byI. typographus were used, and pairs ofT. formicarius were released in the cages. The treatments were: uncaged bolts, caged bolts withoutT. formicarius, caged bolts with 4T. formicarius pairs, and caged bolts with 8T. formicarius pairs. The productivity ofI. typographus was highest in the caged bolts withoutT. formicarius (mean=4.5 offspring/female) and lowest in the uncaged bolts (mean=0.9 offspring/female). The density ofI. typographus galleries was similar in the different treatments. Hence, the variation in productivity between treatments could not have been due to differences in the levels of intraspecific competition. There was no difference in bark beetle productivity or density ofT. formicarius larvae between bolts with 4 pairs ofT. formicarius and bolts with 8 pairs (mean=2.5 offspring/female). This indicates that some kind of interference occurred betweenT. formicarius individuals (e.g. cannibalism) and that a maximum level of predation was reached. Predation by larvae ofMedetera spp. (Diptera, Dolichopodidae),Thanasimus spp. and other beetles, and parasitism by wasps (Hymenoptera, Pteromalidae) probably caused the low productivity in the uncaged bolts.      

Partial characterization and dynamics of synthesis of high molecular mass exopolysaccharides from Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus

Exopolysaccharide (EPS) preparations from Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) strains LBB.B26 and LBB.B332 and Streptococcus thermophilus strains LBB.T54 and LBB.T6V were characterized using ion-exchange chromatography and gel filtration. All four preparations contained a neutral EPS with molecular mass in the range of 1.3−1.6 × 10⁶ Da (HMM-EPS). The EPS preparations from the two L. bulgaricus strains also contained an acidic low molecular mass EPS fraction (LMM-EPS) comprising from 10% to 34% of the total EPS yield. HMM-EPS preparations were subjected to High Pressure Liquid Chromatography (HPLC) analysis of monomer sugars after complete hydrolysis. Glucose, galactose and/or rhamnose in different ratios proved to be the principal sugars building the HMM-EPS from all four strains. The chemical composition of HMM-EPS was strictly strain-specific. The LMM-EPS contained galactose. The viscosifying properties of the four different HMM-EPS varied greatly with intrinsic viscosity in the range from 0.26 (strain B26) to 2.38 (strain T6V). For 24 h the two L. bulgaricus strains accumulated more HMM-EPS in milk (>70 mg l⁻¹) than S. thermophilus strains T54 and T6V (<30 mg l⁻¹), but maximal yields were reached earlier with cocci (8 h) than with rods (16–24 h). The contribution of HMM-EPS production to increased viscosity of fermented milk was demonstrated for all of the tested strains grown as monocultures or as mixed yogurt starters compared to non-EPS producing S. thermophilus LBB.A and poor EPS-producer L. bulgaricus LBB.B5. The extent of increased viscosity was strongly dependent on the nature of the produced HMM-EPS, rather than simply on polymer yield.     

The effect of drought stress on chlorophyll fluorescence in Lolium-Festuca hybrids

The effects of drought on photochemical efficiency of PSII in leaves of 22 hybrids of Festuca pratensis × Lolium multiflorum and Festuca pratensis × Lolium perenne and of Festuca pratensis cv. Skra were investigated. A significant decrease of electron transport efficiency (about 25%) in PSII (Φ_PSII) was not found before 9 days of seedling growth in hydroponics with water potential (Ψ_w) equal to −0.8 MPa (simulated “soil drought”). The decrease of Φ_PSII was similarly related to that of excitation energy capture by open PSII reaction centre (Fv’/Fm’) and also to the decrease of the proportion of oxidized to reduced Q_A (photochemical fluorescence quenching, q_p). According to the drought prolongation, variation of all parameters of fluorescence between genotypes significantly increased. The seedlings of some genotypes were able to recover electron transport efficiency in PSII after increasing water potential in nutrient solution (removing the “soil drought”). When plants grew in containers with soil and 4 genotypes with the highest sensitivity of electron transport to drought (S) as well as 4 genotypes with the highest tolerance (T) were compared 17 days after watering ceased, Ψ_w in leaves considerably decreased, but the differences between S and T genotypes were often not significant in this respect. The differences between S and T genotypes, as values of Fv/Fm were concerned, also appeared small (about 5%), similarly as that of Fv’/Fm’ (5%), q_p (12%) and Φ_PSII (about 15%). Drought stress increased non-photochemical quenching of chlorophyll fluorescence (NPQ) 15 to 47% and this could protect the PSII reaction centres from damages because of energy excess. The increase of NPQ was not closely connected with drought resistance of plants because it was similar in some genotypes tolerant to dehydration as well as in sensitive ones. The results of the experiments suggest that resources of genetic variability in Festulolium may be sufficient for revealing differences between genotypes on the basis of measurement of chlorophyll a fluorescence, as far as their tolerance to soil drought is concerned. As the tolerance of PSII against drought is high, the determinations of fluorescence should be performed rather under severe stress. Such methods seem to be useful for selection of genotypes with high drought tolerance as well as with the ability to at least partial repairing of PSII after drought.     

Rearing of two predators,Thanasimus dubius andTemnochila virescens, for the biological control ofIps grandicollis in Australia

Rearing methods for two coleopterous predators,Thanasimus dubius andTemnochila virescens, imported into Australia for the biological control ofIps grandicollis, were developed. Bionomic data obtained from laboratory rearings between 1982–1987 showed thatT. dubius eggs took about 7 days to hatch and that duration of the larval stage was about 42 days. Observations showed thatT. dubius had a prolonged prepupal stage (x=56.4 days, range 14–274 days), which was probably non-diapausal in nature. Mean adult longevity was 50 days (range 1–358 days).Temnochila virescens eggs took almost 9 days to hatch, and a lengthy larval stage (x=155.4 days, range 73–333 days) was observed. Mean duration of the pupal stage was 14 days (range 7–28 days). A long preoviposition period (x=141 days, range 47–206 days) was observed, and adults were very long-lived (x=232.7 days, range 14–667 days). Capacity for increase (r_c) calculated from rearing data suggested that numbers ofT. dubius could be increased faster thanT. virescens. Mortality between 1982–1987 averaged about 70% for both species. However, mortality ofT. dubius in 1987 increased significantly, suggesting that inbreeding or other methodological factors could be responsible. A mass-rearing method usingIps-infested pine billets was developed as a cheaper alternative to laboratory rearing, and was shown to be effective in producing large numbers of insects for release.