Search

This document contains copyright guidelines determined appropriate for the Citrus County School System (Florida) by the Citrus County Association of School Media Specialists in May, 1992. These guidelines are based on interpretation and understanding of current copyright law as applied to education and implemented in school districts in the United States. A historic perspective and overview of copyright laws and regulations is given, and the school district's policy is outlined. Specific guidelines are listed for the following areas: (1) video tapes and television programs; (2) music; (3) audiovisual works; (4) computer software; (5) photocopying; and (6) local sound slide or video productions. (SLD)

Xanthomonas citri pv. citri (Xcc) (X. citri subsp. citri) type A is the causal agent of citrus bacterial canker (CBC) on most Citrus spp. and close relatives. Two narrow-host-range strains of Xcc, Aw and A*, from Florida and Southwest Asia, respectively, infect only Mexican lime (Citrus aurantifolia) and alemow (C. macrophylla). In the initial stage of infection, these xanthomonads enter via stomata to reach the apoplast. Herein, we investigated the differences in chemotactic responses for wide and narrow-host-range strains of Xcc A, X. euvesicatoria pv. citrumelonis (X. alfalfae subsp. citrumelonis), the causal agent of citrus bacterial spot, and X. campestris pv. campestris, the crucifer black rot pathogen. These strains of Xanthomonas were compared for carbon source use, the chemotactic responses toward carbon compounds, chemotaxis sensor content, and responses to apoplastic fluids from Citrus spp. and Chinese cabbage (Brassica pekinensis). Different chemotactic responses occurred for carbon sources and apoplastic fluids, depending on the Xanthomonas strain and the host plant from which the apoplastic fluid was derived. Differential chemotactic responses to carbon sources and citrus apoplasts suggest that these Xanthomonas strains sense host-specific signals that facilitate their location and entry of stomatal openings or wounds.

Xanthomonas citri subsp. citri (Xcc) causes citrus bacterial canker (CBC) on several Citrus species. Xcc requires bacterial aggregation and biofilm formation to colonize the host plant. Those biofilms are dependent on the environmental condition and their structures differ according to the host range of the Xcc strain. Herein, we have visualized and evaluated the extracellular structures produced by Xcc strains with different host range at early stages of biofilm formation, in mature biofilms and during planktonic growth. Moreover, the presence of these structures was related to the transcription of quorum sensing, flagellar and fimbrial genes. Our results demonstrate that the variation in biofilm formation between Xcc strains is associated with expression of fimbrial and flagellar genes which in some cases is dependent on a quorum sensing system.

This learner's guide is designed to assist middle school students in studying freshwater organisms. Following a brief introduction to freshwater ecology, simple line drawings facilitate the identification of plants and animals common to Florida's freshwater ecosystems. Emphasis of the short text which accompanies each illustration is upon the organism's appearance and habitat. A supplementary set of slides depicting some of the plants and animals discussed is available. (WB)

This collection of booklets deals with minumum standards in mathematics for beginning eleventh grade students. There is a statement of the standards with related skills, a test to assess competency with accompanying answer sheet and answer key, and eight booklets presenting problems covered by six of the standards. The booklets cover: percentages; elapsed time; finding averages; real-world problems involving decimals, fractions, and percents; money; measurement using metric and customary units; and graphs. The problems to be solved are oriented toward environmental and energy subject matter. (Author/MP)

Certain seeds, tubers and roots of plants were evaluated as substrates for mass production of the nematophagous fungus, Paecilomyces lilacinus (Thom.) Samson. Growth of P. lilacinus as measured by diameter of the colony, spore production, weight of mycelial mat and rate of growth indicated that wheat, bajra, jowar, and rice were suitable substrates for the multiplication of P. lilacinus. The population of Tylenchulus semipenetrans Cobb decreased markedly with increase in the inoculum level of P. lilacinus, However, application of P. lilacinus in the form of spore suspension was more effective than infected wheat grains in controlling T. semipenetrans.

The suitability of leaves of certain plant species, oilcakes, as well as waste products of sago industry were evaluated as substrates for mass multiplication of the nematophagous fungus, Paecilomyces lilacinus (Thorn.) Samson. Leaves of subabool and neem were found to be suitable substrates and supported a highcr spore load than tanners cassia, Pongamia and Glyricidia. Tapioca tuber and its peels also supported a moderately high spore load. Untreated thippi supported the least spore load. However, the spore load of P. lilacinus was significantly increased when thippi was soaked in KH2Po4 and NaNO3 at 0.75% concentration. The oilcakes favoured the growth of P. lilacinus.

The effcacy of the bacterial spore parasite, Pasteuria penetrans (Thorne, 1940) Sayre and Starr, 1985 in combination with four oil cakes viz., castor (Ricinus communis L.), gingelly (Sesamum indicum L.), groundnut (Arachis hypogaea L.) and neem (Azadirachta indica Juss.) was tested under greenhouse conditions for the control of Meloidogyne javanica (Treub, 1885) Chitwood, 1949 on tomato cv. Pusa Ruby. The bacterium as well as oil cakes reduced nematode infestation and improved plant growth, but the combination treatments were significantly superior. Among these, P. penetrans applied in combination with neem cake was the best treatment giving 75. reduction in final nematode population.

The selectivity of Mak All Season Horticultural Mineral Oil (MAS-HMO) at different doses (0.1%, 0.5%, 1%, 1.5%, 2.0% , 2.5%) and imidacloprid @ 0.009% was studied against Mallada desjardinsi (Navas) (Neuroptera: Chrysopidae) and Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae), important predators of sucking pests of citrus in Vidarbha region of Maharashtra, under laboratory conditions during 2009, 2010 and 2011. Of the different doses tested, MAS-HMO @ 0.1%, 0.5%, 1.0% and 1.5% recorded significantly high mean egg hatchability (100%) of M. desjardinsi whereas imidacloprid @ 0.009 % recorded significantly low mean egg hatchability (67.2%). Mean grub mortality of M. desjardinsi was significantly low (0%) in doses 0.1%, 0.5% and 1.0% MAS-HMO. However, imidacloprid @ 0.009 % recorded significantly high mean grub mortality (52.2%) of M. desjardinsi whereas, adult mortality was nil in all the doses of MAS-HMO tested. MAS-HMO @ 0.1 %, 0.5% and 1.0% was found safe to the grubs of C. sexmaculata as mortality of the treated grubs was nil. Imidacloprid @ 0.009% recorded significantly high mean grub mortality (41.1%) of C. sexmaculata.