Highest Colony Growth Research Articles

Organic farming and annual flower strips reduce parasite prevalence in honeybees and boost colony growth in agricultural landscapes

Abstract Despite the major role that insect pollinators play in crop production, agricultural intensification drives them into decline. Various conservation measures have been developed to mitigate the negative effects of agriculture on insect pollinators. In a novel comparison of the efficacy of three conservation measures on honeybee colony growth, we monitored experimental honeybee colonies in 16 landscapes that comprised orthogonal gradients of organic agriculture, annual flower strips and perennial semi‐natural habitats. Using structural equation modelling, we assessed the effects of conservation measures on the prevalence of 11 parasites, Varroa destructor loads and their collective impact on colony growth. Increasing area coverage of perennial semi‐natural habitat related to higher V. destructor load and indirectly to lower colony growth. Increasing area of annual flower strips was associated with lower V. destructor load and indirectly with higher colony growth. Increasing area of organic farming related to lower parasite richness and also directly to improved colony growth. Synthesis and applications: Landscape features can affect pollinators directly through the provision of food resources and indirectly through modulation of parasite prevalence. To promote honeybee colony health in agro‐ecosystems, our results suggest that organic agriculture and annual flower strips should be prioritized conservation measures. Landscape management should consider the merits and demerits of different measures to sustain healthy populations of pollinators in agro‐ecosystems.

Laboratory assessment on compatibility of entomopathogenic fungus, <i>Beauveria bassiana</i> Balsamo-vuillemin with imidacloprid 48% FS for bhendi (<i>Abelmoschus esculentus</i> L. moench) seed treatment

Beauveria bassiana (Balsamo-Vuillemin), an effective entomopathogenic fungi is well positioned in the biological control of insect pests for more than ten decades around the world. Its potential can be attributed to the fungus’s entry through several parts of the insect and its mode of action. But sometimes a virulent strain of B. bassiana may become ineffective because of xenobiotics and environmental factors. To enhance the efficacy of B. bassiana, which is necessary for placing it in Integrated Pest Management, the Colony Forming Unit (CFU) of B. bassiana should be compatible with xenobiotics used in crop production. The compatible concentrations of imidacloprid 48% FS (500 ppm) for B. bassiana was studied in the laboratory condition and results revealed low per cent growth inhibition (21.25%) and maximum radial growth (1.46 cm) at 15 Days After Inoculation (DAI). The inhibition of colony growth was reduced by treating the bhendi seeds with B. bassiana and imidacloprid 48 % FS at a time interval of four hours which showed high mean colony growth (51.12).

Optimization of Culture Conditions for Mycelial Growth and Sporulation of Myrothecium roridum

Culture and nutrition conditions of Myrothecium roridum Tode were optimized by conducting a series of interlined experiments on a growth medium, temperature, pH, and photoperiod. In contrast, relation of culture age with virulence was measured by fungal development on young leaves of bitter gourd. The physiological response was measured on colony radial growth and spore production. Among the six test growth media, i.e., nutrient agar (NA), potato dextrose agar (PDA), Czapek-Dox agar (CDA), glucose agar (GA), malt extract agar (MEA), and bitter gourd agar (BGA), the highest radial growth (77 mm) and the highest number of spores (239 × 106 spores/ml) were observed on PDA. Incubation temperature was evaluated between a range of 15-40 °C, and the highest colony growth (87 mm) was observed at 30 °C, whereas the highest spore production (315 × 106 spores/ml) was at 35 °C. Different pH levels, i.e., 5, 5.5, 6, 6.5, 7, and 7.5, were optimized, and the highest colony growth (87 mm) and spore production (504 × 106 spores/ml) was recorded at pH 5.0. Impact of photoperiod was studied, and the highest mycelial growth (88 mm) and maximum spore production (524 × 106 spores/ml) was observed at 16/8 h alternate light and dark period. It was concluded that the optimum conditions for mycelia growth and spore production was pH 5.0-6.0 and at 30 ± 2 °C in PDA with 16/8 h alternate light and dark photoperiod.

Correlation of RAS-Pathway Mutations and Spontaneous Myeloid Colony Growth with Progression and Transformation in Chronic Myelomonocytic Leukemia-A Retrospective Analysis in 337 Patients.

Although the RAS-pathway has been implicated as an important driver in the pathogenesis of chronic myelomonocytic leukemia (CMML) a comprehensive study including molecular and functional analyses in patients with progression and transformation has not been performed. A close correlation between RASopathy gene mutations and spontaneous in vitro myeloid colony (CFU-GM) growth in CMML has been described. Molecular and/or functional analyses were performed in three cohorts of 337 CMML patients: in patients without (A, n = 236) and with (B, n = 61) progression/transformation during follow-up, and in patients already transformed at the time of sampling (C, n = 40 + 26 who were before in B). The frequencies of RAS-pathway mutations (variant allele frequency ≥ 20%) in cohorts A, B, and C were 30%, 47%, and 71% (p < 0.0001), and of high colony growth (≥20/105 peripheral blood mononuclear cells) 31%, 44%, and 80% (p < 0.0001), respectively. Increases in allele burden of RAS-pathway mutations and in numbers of spontaneously formed CFU-GM before and after transformation could be shown in individual patients. Finally, the presence of mutations in RASopathy genes as well as the presence of high colony growth prior to transformation was significantly associated with an increased risk of acute myeloid leukemia (AML) development. Together, RAS-pathway mutations in CMML correlate with an augmented autonomous expansion of neoplastic precursor cells and indicate an increased risk of AML development which may be relevant for targeted treatment strategies.

Supercolonial structure of invasive populations of the tawny crazy ant Nylanderia fulva in the US

BackgroundSocial insects are among the most serious invasive pests in the world, particularly successful at monopolizing environmental resources to outcompete native species and achieve ecological dominance. The invasive success of some social insects is enhanced by their unicolonial structure, under which the presence of numerous queens and the lack of aggression against non-nestmates allow high worker densities, colony growth, and survival while eliminating intra-specific competition. In this study, we investigated the population genetics, colony structure and levels of aggression in the tawny crazy ant, Nylanderia fulva, which was recently introduced into the United States from South America.ResultsWe found that this species experienced a genetic bottleneck during its invasion lowering its genetic diversity by 60%. Our results show that the introduction of N. fulva is associated with a shift in colony structure. This species exhibits a multicolonial organization in its native range, with colonies clearly separated from one another, whereas it displays a unicolonial system with no clear boundaries among nests in its invasive range. We uncovered an absence of genetic differentiation among populations across the entire invasive range, and a lack of aggressive behaviors towards conspecifics from different nests, even ones separated by several hundreds of kilometers.ConclusionsOverall, these results suggest that across its entire invasive range in the U.S.A., this species forms a single supercolony spreading more than 2000 km. In each invasive nest, we found several, up to hundreds, of reproductive queens, each being mated with a single male. The many reproductive queens per nests, together with the free movement of individuals between nests, leads to a relatedness coefficient among nestmate workers close to zero in introduced populations, calling into question the stability of this unicolonial system in which indirect fitness benefits to workers is apparently absent.

High Spontaneous In Vitro Myeloid Colony Formation in Chronic Myelomonocytic Leukemia is Associated with Mutations in Rasopathy Genes, Myeloproliferation and Inferior Prognosis

Background: Chronic myelomonocytic leukemia (CMML) is a hematopoietic malignancy with features of both a myelodysplastic syndrome and a myeloproliferative neoplasm.The pathogenesis of CMML is incompletely understood due to the large heterogeneity of molecular aberrations in genes involved in epigenetic regulation, RNA-splicing and signal transduction including components of RAS and JAK2 signaling. Functional tests may be important to better estimate the contribution of a particular molecular aberration in the pathogenesis of the malignancy. We have originally demonstrated extensive in vitro formation of myeloid colonies (CFU-GM) without addition of exogenous growth factors in a subset of patients with CMML (Geissler et al, Leuk Res 1988). We reported that this spontaneous CFU-GM colony formation in CMML is a GM-CSF dependent in vitro phenomenon (Geissler et al, J Exp Med 1996) and could also show in a small retrospective study that CMML patients with high spontaneous CFU-GM growth (>100/105 PBMNC) have a worse prognosis compared to patients with low myeloid colony formation (Sagaster et al, Ann Hematol 2004) suggesting a clinical significance of our observation. In juvenile myelomonocytic leukemia, in which molecular aberrations are mainly restricted to the RASopathy genes including NRAS, KRAS, NF1, CBL and PTPN11, spontaneous formation of CFU-GM due to GM-CSF-specific hypersensitivity is a hallmark feature of disease, which has been included in the diagnostic criteria. We therefore speculated that high spontaneous myeloid colony formation in CMML might also reflect hyperactivation of the RAS signaling pathway.Aim: Our aim was to study the correlation between spontaneous myeloid colony formation and the presence of mutations in RASopathy genes in patients with CMML. Moreover the relationship of high autonomous CFU-GM formation with phenotypic features of CMML and its clinical outcome was investigated.Patients and Methods: In this study we included 137 CMML patients of the "Austrian Biodatabase for CMML (ABCMML)" in whom CFU-GM data and/or molecular data were available. CFU-GM growth in the absence of exogenous cytokines was assessed in a central laboratory using semisolid cultures as previously described (Geissler et al, J Exp Med 1996). Molecular characterization was also performed in a central laboratory using NGS with amplicon-based target enrichment of 39 CMML associated genes. Assuming that clones that are too small are unlikely to significantly impact hematopoiesis only mutations with an allele burden of ≥20% were considered positive in this analysis. Clinical and hematological data were obtained from patients records.Results:High spontaneous CFU-GM growth (≥100/105 PBMNC) was found in 38/135 (28%) CMML patients, of whom 3 were already transformed into secondary AML at the time of in vitro culture testing. There was a significant correlation between high CFU-GM formation in vitro and the presence of mutations in genes involved in the RAS signaling pathway. The incidence of RAS pathway mutations was 72% in CMML patients with high colony growth and 31% in patients with low spontaneous CFU-GM formation (p<0.0001). As shown in Table 1 high spontaneous myeloid colony formation was associated with increased WBC counts, increased blast cells, increased LDH, more pronounced splenomegaly and inferior survival (Fig. 1). There was no significant difference regarding autonomous CFU-GM growth in CMML patients with molecular aberrations in genes of epigenetic regulation and RNA-splicing, respectively. High spontaneous CFU-GM was never observed in CMML patients in whom the JAK2 V617F mutation was the only molecular aberration in signaling pathways (0/8 patients). Furthermore the in vitro conversion from a growth factor dependent to a growth factor independent phenotype by RAS but not by JAK2 could be demonstrated in BaF3 cells (Fig. 2).Conclusion: Our findings indicate that high spontaneous in vitro myeloid colony formation is associated with the presence of RAS pathway mutations, leukocytosis, splenomegaly and reduced survival. These results suggest that CMML with high spontaneous colony growth is a mainly RAS pathway driven malignancy resulting in myeloproliferation and inferior outcome. This may have clinical implications concerning therapeutic strategies aimed at targeting the hyperactive RAS signaling pathway in these patients. [Display omitted] [Display omitted] [Display omitted] DisclosuresGeissler:Novartis: Honoraria. Pfeilstöcker:Novartis: Consultancy, Speakers Bureau. Burgstaller:Novartis: Consultancy, Honoraria. Zach:Novartis: Other: Honoraria for Advisory Board. Hörmann:Novartis: Other: Honoraria for Advisory Board. Jäger:Roche: Other: Personal fees, Research Funding. Sperr:Amgen: Honoraria, Research Funding; Novartis: Honoraria. Kusec:Novartis: Other: Honoraria for lectures. Valent:Amgen: Honoraria; Novartis: Honoraria, Research Funding; Celegene: Honoraria, Research Funding.

Optimization of Buffalo (Bubalus bubalis) Embryonic Stem Cell Culture System.

In order to retain an undifferentiated pluripotent state, embryonic stem (ES) cells have to be cultured on feeder cell layers. However, use of feeder layers limits stem cell research, since experimental data may result from a combined ES cell and feeder cell response to various stimuli. In this experimental study, a buffalo ES cell line was established from in vitro derived blastocysts and characterized by the Alkaline phosphatase (AP) and immunoflourescence staining of various pluripotency markers. We examined the effect of various factors like fibroblast growth factor 2 (FGF-2), leukemia inhibitory factor (LIF) and Y-27632 to support the growth and maintenance of bubaline ES cells on gelatin coated dishes, in order to establish feeder free culture systems. We also analyzed the effect of feeder-conditioned media on stem cell growth in gelatin based cultures both in the presence as well as in the absence of the growth factors. The results showed that Y-27632, in the presence of FGF-2 and LIF, resulted in higher colony growth and increased expression of Nanog gene. Feeder-Conditioned Medium resulted in a significant increase in growth of buffalo ES cells on gelatin coated plates, however, feeder layer based cultures produced better results than gelatin based cultures. Feeder layers from buffalo fetal fibroblast cells can support buffalo ES cells for more than two years. We developed a feeder free culture system that can maintain buffalo ES cells in the short term, as well as feeder layer based culture that can support the long term maintenance of buffalo ES cells.

Characterization of Bipolaris maydis isolates of different maize cropping zones of India

An experiment was conducted to study cultural, morphological and pathogenic variability in 12 isolates of Bipolaris maydis from different maize cropping zones of India. The isolates showed considerable variability in their cultural characteristics, morphology and pathogenicity to maize ( Zea mays L.). All the isolates produced dark coloured, fusoid conidia, measuring 6.14-23.41 µm × 2.15-5.70 µm. The conidia of MDCh1 isolate was largest (19.6 µm × 5.0 µm), whereas MUCh3 isolate produced smallest (9.7 µm × 3.3 µm) conidia. The average number of septa varied from 2 to 8. The isolate, MLCh1, showed highest number of septa (5.0). Isolate, MDCh1 (Delhi), showed maximum colony diameter and MLCh1 (Ludhiana), the minimum. However, growth on different culture media, revealed that, MKCh1 (Kangra), MDCh1 (Delhi) and MUCh6 (Udaipur) registered highest colony growth on PDA and Richard’s agar respectively, while MLCh1 (Ludhiana) registered minimum colony growth on both PDA and Richard’s agar media. The colour of mycelium of specific isolates varied between media. In a majority of the isolates, the colour was black ranging from light black, light grey, light green and grey. The colony texture was rough to smooth, regular to irregular margin with or without zonation. Pathogenicity test of isolates conducted under glasshouse conditions revealed that MKCh1 isolate was highly virulent with the highest disease score (3.6) in susceptible hybrid line and MUCh3 as the least virulent with disease score of 1.4 only. Apparently, all the isolates of B. maydis were virulent under glasshouse conditions.

Insecticidal potential of Paenibacillus elgii HOA73 and its combination with organic sulfur pesticide on diamondback moth, Plutella xylostella

Diamondback moth, Plutella xylostella, is one of the most destructive insect pests of several crops world-wide. Effects of Paenibacillus elgii HOA73 and its combined application with organic sulfur pesticide on Plutella xylostella were evaluated. Results showed that M3 medium composition indicated the best medium for optimization of bacterial colony growth, hydrolytic enzyme production, and insecticidal activity and was selected for culturing P. elgii HOA73 in further assays. The highest colony growth of P. elgii HOA73 was identified at 5 days after inoculation. Extracted crude enzyme and crude insecticidal compound from P. elgii HOA73 cultured in the optimized medium kill the second instar larvae of Diamondback moth in 40 and 50% at 220mg mL−1 of crude enzyme and 2% crude extract, respectively. Combined application of organic sulfur pesticide with bacterial suspension significantly killed 85% second instar larvae of Diamondback moth, when compared to use of single application: bacterial suspension (65%) and organic sulfur pesticide (38%), suggesting that P. elgii HOA73 combined with organic sulfur pesticide could be used to control P. xylostella.

Combined effect of chemical fertilisers and rhizosphere-competent Bacillus subtilis BSK17 on yield of Cicer arietinum

A chemical fertiliser-adaptive variant, Bacillus subtilis BSK17, showed induction in growth at 0.32 M of Urea, 0.05 M of DAP, 0.04 M of MoP and 0.08 of gypsum. In addition, B. subtilis BSK17 produced various plant growth-promoting substances and showed higher colony growth inhibition of Fusarium oxysporum that increased with increase in incubation time and reached the maximum by 78% at 120 h. In field, antibiotic-resistant marker strains of B. subtilis BSK17ery+ and B. subtilis BSK17tet+ showed more improvement in seed yield (90% than the control and 24% than full dose of chemical fertilisers) of Cicer arietinum when applied with half dose of chemical fertilisers (N5+5P15+15K15S10+10+10). Root length, shoot length, fresh and dry weight of root and shoot of plants were enhanced after 120 days in comparison to control; all values were significant at 1% CD. The strain significantly colonised the rhizosphere of C. arietinum by 6.64 log cfu after 120 days.

Media composition influences on growth, enzyme activity, and virulence of the entomopathogen hyphomycete Isaria fumosoroseus

AbstractThree isolates of Isaria fumosoroseus Wize (Hyphomycetes) were cultured on six media composed of differing amounts of chitin, carbon, and nitrogen. The effect of nutrition on growth and virulence was studied by measuring colony growth, spore yield, germination rate, spore‐bound protease (Pr1) and lipase activity, and virulence of inoculum produced by different media against second instars of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae). Chitin peptone nutrition media resulted in the highest colony growth but spore yields were lowest for this medium, whereas the osmotic stress medium resulted in the lowest colony growth with fewer spores. Highest lipase activity (4.14 µmol/ml/min) was observed for spores produced on high C/N medium for isolate IF28.2, whereas highest Pr1 activity (2.64 µmol/ml/min) was also observed on high C/N medium for isolate IF28.2. A higher rate of Pr1 and lipase activity for all three isolates was observed on low C/N, 2% peptone, and the osmotic stress media. Conidia from nutrient‐poor media (2% peptone) proved to be the least virulent for all three isolates with median survival time values of 2.23, 2.05, and 1.79 days for IF32, IF28.2, and IF49, respectively. Median survival time values for the various nutrient media proved to be positively correlated with spore‐bound Pr1 and lipase activity, having correlation coefficient values of 0.115 and 0.538, respectively.

The Use By Red Imported Fire Ants, Solenopsis Invicta (Hymenopgefa: Formicidae), Of Potamogeton Nodosus (Potamogetonaceae) Leaves As Platforms Into The Littoral Zone In Texas, U.S.A

It has become increasingly clear that waterways facilitate the invasion process for many species, including terrestrial species, such as ants (Walker 2006). The underlying reason may be directly related to transportation, as in the case of the red imported fire ant, Solenopsis invicta Buren whose colonies can spread by rafting on moving water (Banks et al., 1981). In other instances, periodic flooding along riparian courses often creates disturbance regimes, which promote invasions (Ellis et al., 2001). Additional habitat considerations include elevated soil moisture (Holway et al., 2002) and high productivity associated with riparian ecosystems (Kennedy 1998, Paetzold et al., 2006). These conditions are likely to promote high colony growth rates and an associated higher propagule pressure, furthering the invasion process. Ants that are predisposed to be around water are more likely to be able to take opportunistic advantage of waterways for their dispersal (Suarez et al., 2005). Many Solenopsis species, especially the most widely distributed species, commonly forage around water (Wilson 1986). The black imported fire ant, for instance, has been found preying on tubeworms exposed during low tides (Palomo et al., 2003), while S. invicta is considered a threat to wildlife in wetland habitats (Freed and Neitman 1988). The latter study noted that the fire ants were able to extend their reach into the pond by utilizing unspecified vegetation as a walkway but gave no additional details. This note offers further information as to the use by fire ants of floating vegetation as natural roads. In June of 2002, I first observed S. invicta workers crossing long leaf pondweed, Potamotegon nodusus leaves lying on the water surface of a manmade lake in Lee County, TX (N30.14, W96.88). Potamotegon nodosus is a fast-growing aquatic plant that forms extensive platforms of networked leaves on the water surface of the littoral zone. In the situation observed, these platforms were growing in an emergent area of the lake with seasonal inundation. I was able to observe the ants closely out over the water because of the presence of a 15m long raised pier that paralleled the pondweed. Many of my observations were made using a Sony PCV DCR-TRV9. Volume 118, Number 5, November and December 2007 527

Effect of pH, temperature, light duration and incubation period for growth and sporulation of &lt;i&gt;Stemphylium botryosum&lt;/i&gt; wallr

A study was undertaken to find out the effect of seven pH levels, six temperature regimes, five light durations and five incubation periods on radial colony growth and spore production of Stemphylium botryosum in petridishes (90 mm diameter) containing carrot dextrose agar (CDA) medium. Higher colony growth and spore production were reccorded within the pH range of 6-8, temperature regime of 20-25°C and incubation period of 5-25 days as compared to other levels of each growth factors. The maximum mycelial growth and sporulation was observed at pH 6, 25°C, incubated for 15 days under a 24 hr light-darkness cycle. Bangladesh J. Agril. Res. 32(2) 2007: 255-260.

Relation of in vitro growth characteristics to cytogenetics and treatment outcome in acute myeloid leukemia: prognostic significance in patients with a normal karyotype.

We analyzed in vitro growth characteristics of bone marrow mononuclear cells (BMMCs) from 322 patients with acute myeloid leukemia (AML) in relation to cytogenetic abnormalities. Median colony growth was low in each of the cytogenetic changes associated with a favorable outcome. Most karyotypic abnormalities in the intermediate prognosis group were associated with low growth potential, but 11 q23 abnormalities exhibited 8 times higher in vitro growth. Cytogenetic changes that included abn(3q) seemed to display the highest colony growth in the unfavorable prognosis group, whereas isolated -7 may have been associated with limited growth potential. In vitro growth behavior was predictive of neither rate of complete remission (CR) nor survival of AML patients within the 3 cytogenetic risk groups. In contrast, colony growth differed significantly in the subgroup of patients with a normal karyotype who achieved remission with induction treatment and those who had no remission (10 versus 81.5/10(5) BMMCs; P = .015). Significantly more patients with normal cytogenetics and colony growth below the 50th percentile went into CR than did patients with colony growth above the 50th percentile (82.8% versus 71.2%). Only 4 (6.8%) of the patients in the low growth group had no remission, compared with 12 (23.1%) of the patients with higher in vitro growth (P = .031, chi-square test). In conclusion, colony growth may prove useful as a prognostic factor for early treatment failure in AML patients with a normal karyotype.

High spontaneous colony growth in chronic myelomonocytic leukemia correlates with increased disease activity and is a novel prognostic factor for predicting short survival.

We have originally shown that spontaneous granulocyte/macrophage colony (CFU-GM) formation in semisolid medium is a characteristic in vitro feature of chronic myelomonocytic leukemia (CMML). However, the clinical significance of spontaneous CFU-GM growth in CMML is unknown so far. CFU-GM growth characteristics were studied in semisolid cultures in the absence of exogenous cytokines using peripheral blood mononuclear cells in 30 patients with CMML at first presentation. The median number of CFU-GM/10(5) MNC of all patients was 48.5 (range 0-622) with 18 patients having colony numbers below 100 (low CFU-GM growth) and 12 patients above 100 (high CFU-GM growth). Kaplan-Meier analysis revealed that patients with high CFU-GM growth had a significantly shorter survival than patients with low CFU-GM growth (median 6.5 vs. 44.5 months, p<0.00002). The probability of survival after 2 years was 60.5% for patients with low colony growth but 0% in those with high colony formation. Patients with CFU-GM >100 had a significantly higher WBC count, a higher LDH, and a higher number of blast cells in blood and bone marrow than patients with low colony growth. Moreover, patients with high colony growth had more often splenomegaly and lower platelet counts. In seven patients, in whom semisolid in vitro cultures were performed after transformation into RAEBT/AML, spontaneous colony growth was significantly increased as compared to CFU-GM growth in patients before transformation (median number/10(5) MNC 533, range 212-4553, p<0.005). This study demonstrates that high (>100) spontaneous CFU-GM formation in CMML at presentation correlates with increased disease activity and represents a novel and important prognostic factor predicting for short survival of CMML patients.

The gorgonian coral Acabaria biserialis : life history of a successful colonizer of artificial substrata

The azooxanthellate coral Acabaria biserialis Kukenthal, 1908 (Octocorallia: Alcyonacea) is highly abundant on the vertical underwater structures of the oil jetties at Eilat (Red Sea), but it is rare on the adjacent natural reefs. To understand its success on such artificial substrata we examined various aspects of its life history and population dynamics. A. biserialis is a gonochoric brooder. The percentage of colonies on the artificial substrata bearing gonads ranged from none (September 1994 and 1995) to 100% (January 1994, 1995 and April 1994). Mature oocytes and sperm sacs reached rather small maximum diameters of 240 and 160 μm, respectively, probably dictated by the small gastrovascular cavities. A continuous release of planulae was observed in the laboratory from March to July 1995. Planulation occurred during various lunar phases, and both by day and night. Recruitment of A. biserialis on PVC plates attached to the jetties coincided with the breeding period inferred from the laboratory findings. Recruits reached a maximum height of 3 cm within 3 months, thus exhibiting a remarkably rapid growth rate compared with other gorgonians. This high colony growth rate may compensate for the lack of clonal propagation in the studied A. biserialis population. The complex substrata of the jetties provide the conditions required for successful colonization, which include upside-down orientation, an adequate light regime and exposure to flow. The findings of our study may provide a useful contribution to the design of artificial reefs aimed at attracting rapid colonization by A. biserialis colonies.

Molecularly characterized factors governing the growth of murine multipotent stem cells in serum-depleted marrow cultures.

The growth requirements of normal murine marrow-derived multipotent stem cells (CFU-GEMM) in a simple clonal cell culture system substantially devoid of exogenous serum proteins was assessed. The ability of murine interleukin-3 (Il-3), recombinant human erythropoietin (rEPO), and a crystalline preparation of the protoporphyrin hemin to support colony growth in "serum-free" cultures was examined by titration. The results suggest that both Il-3 and hemin are limiting for multipotential colony growth in "serum-free" cultures, but that EPO is not. In addition, the 'sensitivity' of CFU-GEMM to each growth factor appeared to increase in the "serum-free" environment as evidenced by a "shift-to-the-left" in all the titration curves. Nearly half of the GEMM colonies grew to full maturity in the absence of exogenous EPO. Given the optimal concentration of each growth factor, high colony growth was consistently observed in the "serum-free" cultures, with a range from 65% to 119% of the serum control level. It is therefore concluded that supplementation of murine marrow cultures with Il-3 and hemin alone may provide the necessary setting for studying the factors which modulate the growth of multipotent stem cells in a serum-free environment.