Tests of Light-Lepton Universality in Angular Asymmetries of B^{0}→D^{*-}ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189  fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

Precise Measurement of the D_{s}^{+} Lifetime at Belle II

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207  fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9)  fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189  fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3  GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

Search for an Invisible Z^{'} in a Final State with Two Muons and Missing Energy at Belle II

The L_{μ}-L_{τ} extension of the standard model predicts the existence of a lepton-flavor-universality-violating Z^{'} boson that couples only to the heavier lepton families. We search for such a Z^{'} through its invisible decay in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7  fb^{-1}. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×10^{-3} at low Z^{'} masses to 1 at Z^{'} masses of 8  GeV/c^{2}.

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II

We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8  fb^{-1}, produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} and τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. We report 95% confidence-level upper limits on the branching-fraction ratio B(τ^{-}→e^{-}α)/B(τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ}) in the range (1.1-9.7)×10^{-3} and on B(τ^{-}→μ^{-}α)/B(τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}) in the range (0.7-12.2)×10^{-3} for α masses between 0 and 1.6  GeV/c^{2}. These results provide the most stringent bounds on invisible boson production from τ decays.

Antibody drug conjugates as targeted cancer therapy: past development, present challenges and future opportunities

Antibody drug conjugates (ADCs) are promising cancer therapeutics with minimal toxicity as compared to small cytotoxic molecules alone and have shown the evidence to overcome resistance against tumor and prevent relapse of cancer. The ADC has a potential to change the paradigm of cancer chemotherapeutic treatment. At present, 13 ADCs have been approved by USFDA for the treatment of various types of solid tumor and haematological malignancies. This review covers the three structural components of an ADC-antibody, linker, and cytotoxic payload-along with their respective structure, chemistry, mechanism of action, and influence on the activity of ADCs. It covers comprehensive insight on structural role of linker towards efficacy, stability & toxicity of ADCs, different types of linkers & various conjugation techniques. A brief overview of various analytical techniques used for the qualitative and quantitative analysis of ADC is summarized. The current challenges of ADCs, such as heterogeneity, bystander effect, protein aggregation, inefficient internalization or poor penetration into tumor cells, narrow therapeutic index, emergence of resistance, etc., are outlined along with recent advances and future opportunities for the development of more promising next-generation ADCs.

Observation of e^{+}e^{-}→ωχ_{bJ}(1P) and Search for X_{b}→ωϒ(1S) at sqrt[s] near 10.75 GeV

We study the processes e^{+}e^{-}→ωχ_{bJ}(1P) (J=0, 1, or 2) using samples at center-of-mass energies sqrt[s]=10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7  fb^{-1} of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the ϒ(4S) resonance. We report the first observation of ωχ_{bJ}(1P) signals at sqrt[s]=10.745  GeV. By combining Belle II data with Belle results at sqrt[s]=10.867  GeV, we find energy dependencies of the Born cross sections for e^{+}e^{-}→ωχ_{b1,b2}(1P) to be consistent with the shape of the ϒ(10753) state. These data indicate that the internal structures of the ϒ(10753) and ϒ(10860) states may differ. Including data at sqrt[s]=10.653  GeV, we also search for the bottomonium equivalent of the X(3872) state decaying into ωϒ(1S). No significant signal is observed for masses between 10.45 and 10.65  GeV/c^{2}.

Measurement of the Λ_{c}^{+} Lifetime

An absolute measurement of the Λ_{c}^{+} lifetime is reported using Λ_{c}^{+}→pK^{-}π^{+} decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2  fb^{-1}. The result, τ(Λ_{c}^{+})=203.20±0.89±0.77  fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.

Search for a Dark Photon and an Invisible Dark Higgs Boson in μ^{+}μ^{-} and Missing Energy Final States with the Belle II Experiment

The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A^{'} and h^{'} in the dark Higgsstrahlung process e^{+}e^{-}→A^{'}h^{'} with A^{'}→μ^{+}μ^{-} and h^{'} invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34  fb^{-1}, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7-5.0 fb on the cross section and in the range of 1.7×10^{-8}-200×10^{-8} on the effective coupling ϵ^{2}×α_{D} for the A^{'} mass in the range of 4.0  GeV/c^{2}<M_{A^{'}}<9.7  GeV/c^{2} and for the h^{'} mass M_{h^{'}}<M_{A^{'}}, where ϵ is the mixing strength between the standard model and the dark photon and α_{D} is the coupling of the dark photon to the dark Higgs boson. Our limits are the first in this mass range.

Punzi-loss:: a non-differentiable metric approximation for sensitivity optimisation in the search for new particles

We present the novel implementation of a non-differentiable metric approximation and a corresponding loss-scheduling aimed at the search for new particles of unknown mass in high energy physics experiments. We call the loss-scheduling, based on the minimisation of a figure-of-merit related function typical of particle physics, a Punzi-loss function, and the neural network that utilises this loss function a Punzi-net. We show that the Punzi-net outperforms standard multivariate analysis techniques and generalises well to mass hypotheses for which it was not trained. This is achieved by training a single classifier that provides a coherent and optimal classification of all signal hypotheses over the whole search space. Our result constitutes a complementary approach to fully differentiable analyses in particle physics. We implemented this work using PyTorch and provide users full access to a public repository containing all the codes and a training example.

Transfer of CVD-grown graphene for room temperature gas sensors

An easy transfer procedure to obtain graphene-based gas sensing devices operating at room temperature (RT) is presented. Starting from chemical vapor deposition-grown graphene on copper foil, we obtained single layer graphene which could be transferred onto arbitrary substrates. In particular, we placed single layer graphene on top of a SiO₂/Si substrate with pre-patterned Pt electrodes to realize a chemiresistor gas sensor able to operate at RT. The responses to ammonia (10, 20, 30 ppm) and nitrogen dioxide (1, 2, 3 ppm) are shown at different values of relative humidity, in dark and under 254 nm UV light. In order to check the sensor selectivity, gas response has also been tested towards hydrogen, ethanol, acetone and carbon oxide. Finally, a model based on linear dispersion relation characteristic of graphene, which take into account humidity and UV light effects, has been proposed.

Hybrid opto-chemical doping in Ag nanoparticle-decorated monolayer graphene grown by chemical vapor deposition probed by Raman spectroscopy

The novel opto-chemical doping effect in Ag nanoparticle-decorated monolayer graphene grown by chemical vapor deposition has been investigated using Raman spectroscopy for the first time. We used both noble metal nanoparticles and optical excitation, in a hybrid opto-chemical route, to tune the doping level in graphene. Metal nanoparticle-induced chemical effects and laser power-induced substrate effects alter the doping nature of graphene from p- to n-type. Compared with earlier studies, the proposed method significantly lowers the laser intensity required for optical power-dependent doping, resulting in prevention of damage to the sample due to local heating. Some other interesting observations are the enhanced peak intensity in the Raman spectrum of graphene, enhancement of the D-band intensity and the introduction of G-band splitting. This novel, cheap and easily implemented hybrid optical-chemical doping strategy could be very useful for tuning graphene plasmons on the widely used Si/SiO₂ substrates for various photonic device applications.

Tunable optical properties of graphene oxide by tailoring the oxygen functionalities using infrared irradiation

The modification of individual oxygen functional groups and the resultant optical properties of a graphene oxide suspension were investigated using a controlled photothermal reduction by infrared irradiation. The evolution of the structural and optical characteristics of GO suspensions was obtained from Raman spectra, x-ray photoelectron spectroscopy, optical absorption, and steady state and time-resolved photoluminescence spectroscopy. The results suggest the gradual restoration of sp(2) clusters within the sp(3) matrix with an increase of the reduction time and power density. The yellow-red emission (∼610 nm) originated from the defect-assisted localized states in GO due to epoxy/hydroxyl (C-O/-OH) functional groups and that of the blue emission (∼500 nm) was ascribed to the carbonyl (C=O)-assisted localized electronic states. With an increase in the reduction time and IR power density, the intensity of the yellow-red emission was found to decrease, with the blue emission being prominent. These experimental findings open up a new dimension for controlling the optical absorption and emission properties of graphene oxide by tailoring the oxygen functional groups, which may lead to the potential application of graphene-based optoelectronic devices.

Gene space dynamics during the evolution of Aegilops tauschii, Brachypodium distachyon, Oryza sativa, and Sorghum bicolor genomes

Nine different regions totaling 9.7 Mb of the 4.02 Gb Aegilops tauschii genome were sequenced using the Sanger sequencing technology and compared with orthologous Brachypodium distachyon, Oryza sativa (rice), and Sorghum bicolor (sorghum) genomic sequences. The ancestral gene content in these regions was inferred and used to estimate gene deletion and gene duplication rates along each branch of the phylogenetic tree relating the four species. The total gene number in the extant Ae. tauschii genome was estimated to be 36,371. The gene deletion and gene duplication rates and total gene numbers in the four genomes were used to estimate the total gene number in each node of the phylogenetic tree. The common ancestor of the Brachypodieae and Triticeae lineages was estimated to have had 28,558 genes, and the common ancestor of the Panicoideae, Ehrhartoideae, and Pooideae subfamilies was estimated to have had 27,152 or 28,350 genes, depending on the ancestral gene scenario. Relative to the Brachypodieae and Triticeae common ancestor, the gene number was reduced in B. distachyon by 3,026 genes and increased in Ae. tauschii by 7,813 genes. The sum of gene deletion and gene duplication rates, which reflects the rate of gene synteny loss, was correlated with the rate of structural chromosome rearrangements and was highest in the Ae. tauschii lineage and lowest in the rice lineage. The high rate of gene space evolution in the Ae. tauschii lineage accounts for the fact that, contrary to the expectations, the level of synteny between the phylogenetically more related Ae. tauschii and B. distachyon genomes is similar to the level of synteny between the Ae. tauschii genome and the genomes of the less related rice and sorghum. The ratio of gene duplication to gene deletion rates in these four grass species closely parallels both the total number of genes in a species and the overall genome size. Because the overall genome size is to a large extent a function of the repeated sequence content in a genome, we suggest that the amount and activity of repeated sequences are important factors determining the number of genes in a genome.

Fluoride-induced immunotoxicity in adult male albino rat: a correlative approach to oxidative stress

Fluoride pollution in drinking water is an international problem as the fluoride present is often at levels above acceptable limits. In the studies reported here, sodium fluoride (NaF) treatment of rats by gavage for 28 days resulted in the induction of oxidative stress and immunotoxicity. It was shown here that NaF treatment lowered cellular immunity in the rats as illustrated by a significant diminution in peripheral blood lymphocyte, monocyte and neutrophil counts in conjunction with a reduction in splenocyte counts. Effects of NaF treatment on humoral immunity were reflected here in a lowering of the levels of plasma IgG specific to a test antigen (i.e., bovine serum albumin). Disorganization in the histoarchitecture was also noted in the host spleen and thymus after NaF treatment. To determine if oxidative stress was among the potential possible causes for the observed induced immunotoxicities, catalase and peroxidase activities along with malondialdehyde (MDA, product of free radical damage to cells) levels in the spleen and peripheral blood packed cells were also measured. The results indicated that there was a significant diminution in the activities of both the enzymes along with an elevation in MDA levels in both the tissues in treated rats. This report highlights the proposition that chronic exposure to fluoride contaminated drinking water is likely to result in immunotoxicity and, furthermore, that the damage to primary immune organs is due to an induction of oxidative stress.

What can comparative genomics tell us about species concepts in the genus Aspergillus?

Understanding the nature of species" boundaries is a fundamental question in evolutionary biology. The availability of genomes from several species of the genus Aspergillus allows us for the first time to examine the demarcation of fungal species at the whole-genome level. Here, we examine four case studies, two of which involve intraspecific comparisons, whereas the other two deal with interspecific genomic comparisons between closely related species. These four comparisons reveal significant variation in the nature of species boundaries across Aspergillus. For example, comparisons between A. fumigatus and Neosartorya fischeri (the teleomorph of A. fischerianus) and between A. oryzae and A. flavus suggest that measures of sequence similarity and species-specific genes are significantly higher for the A. fumigatus - N. fischeri pair. Importantly, the values obtained from the comparison between A. oryzae and A. flavus are remarkably similar to those obtained from an intra-specific comparison of A. fumigatus strains, giving support to the proposal that A. oryzae represents a distinct ecotype of A. flavus and not a distinct species. We argue that genomic data can aid Aspergillus taxonomy by serving as a source of novel and unprecedented amounts of comparative data, as a resource for the development of additional diagnostic tools, and finally as a knowledge database about the biological differences between strains and species.

Management of fluoride induced testicular disorders by calcium and Vitamin-E co-administration in the albino rat

Fluoride contamination of drinking water can disrupt male gametogenesis and steroidogenesis and induce testicular oxidative stress. Treatment of rats with sodium fluoride at the dose of 20 mg/kg/day for 28 days resulted in significant diminution of testicular Delta5,3beta-hydroxysteroid dehydrogenase (HSD) and 17beta-hydroxysteroid dehydrogenase (HSD) activities and low plasma levels of testosterone, follicular stimulating hormone (FSH) and leutinizing hormone (LH). Spermatogenesis inhibited after sodium fluoride treatment has been assessed here by the quantification of different generation of germ cells like spermatogonia A (ASg), preleptotene spermatocyte (PLSc), midpachytene spermatocyte (MPSc) and step 7 spermatid (7Sd) at stage VII of seminiferous epithelial cycle. Furthermore, fluoride treatment was associated with low activities of testicular, prostatic and epididymal catalase (CAT), superoxide dismutase (SOD) and peroxidase along with elevation of malondialdehyde (MDA) and conjugated dienes (CD) in those tissues. Co-administration of calcium and Vitamin-E with fluoride resulted in a significant recovery from testicular disorders and oxidative stress in the testis and male accessory sex organs. The results of this study demonstrate that fluoride exposure, at the dose available in drinking water in contaminated areas, led to inhibition of testicular gametogenesis and steroidogenesis in association with oxidative stress in the testis and male accessory sex organs, which are protected significantly by dietary agents like Vitamin-E and calcium.

Antidiabetic effect of aqueous extract of seed of Tamarindus indica in streptozotocin-induced diabetic rats

In Indian traditional system of medicine, herbal remedies are prescribed for the treatment of diseases including diabetes mellitus. In recent years, plants are being effectively tried in a variety of pathophysiological states. Tamarindus indica Linn. is one of them. In the present study, aqueous extract of seed of Tamarindus indica Linn. was found to have potent antidiabetogenic activity that reduces blood sugar level in streptozotocin (STZ)-induced diabetic male rat. Supplementation of this aqueous extract by gavage at the dose of 80 mg/0.5 ml distilled water/100 g body weight per day in STZ-induced diabetic rat resulted a significant diminution of fasting blood sugar level after 7 days. Continuous supplementation of this extract for 14 days resulted no significant difference in this parameter from control level. Moreover, this supplementation produced a significant elevation in liver and skeletal muscle glycogen content, activity of liver glucose-6-phosphate dehydrogenase in respect to diabetic group. Activities of liver glucose-6-phosphatase, liver and kidney glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities were decreased significantly in the aqueous extract supplemented group in respect to diabetic group. All these parameters were not resettled to the controlled level after 7 days of this extract supplementation but after 14 days of this supplementation, all the above mentioned parameters were restored to the control level.

Effect of Stephania hernandifolia leaf extract on testicular activity in rats

AIM

The testicular inhibitory effect of the aqueous fraction of methanol extract of Stephania hernandifolia leaf was studied in male Wistar rats.

METHODS

The supernatent and the precipitate part of aqueous fractions of the methanol extract of the leaf were gavaged separately to rat at a similar dose of 200 mg/mL per 100 g body weight per day for 28 days. After cessation of treatment, various observations were conducted.

RESULTS

In both treated groups, there were significant decreases in the relative weights of the sex organs, the testicular key androgenic enzymes activities, the plasma level of testosterone, the number of different germ cells at stage VII of seminiferous epithelial cell cycle and the seminiferous tubular diameter in comparison to the controls. Neither of the parts had somatic, renal and hepatic toxicity. This study suggested that the active molecules present in the aqueous fraction of methanol extract of Stephania hernandifolia leaves might be steroids as indicated by thin layer chromatography using specific staining substance for steroid molecules.

CONCLUSION

In rats, the aqueous fraction of methanol extract of the S. hernandifolia leaves possesses certain testis-inhibitory substances, which may be steroid-like agents.

Testicular toxicity in sodium fluoride treated rats: association with oxidative stress

This study examined the effect of sodium fluoride, a water pollutant important through the world, including India, on testicular steroidogenic and gametogenic activities in relation to testicular oxidative stress in rats. Sodium fluoride treatment at 20mg/kg/day for 29 days by oral gavage resulted in significant diminution in the relative wet weight of the testis, prostate, and seminal vesicle without alteration in the body weight gain. Testicular delta(5),3beta-hydroxysteroid dehydrogenase (HSD) and 17beta-HSD activities were decreased significantly along with significant diminution in plasma levels of testosterone in the fluoride-exposed group compared to the control. Epididymal sperm count was decreased significantly in the fluoride-treated group and qualitative examination of testicular sections revealed fewer mature luminal spermatozoa in comparison to the control. The seminiferous tubules were dilated in treated animals. Fluoride treatment was associated with oxidative stress as indicated by an increased level of conjugated dienes in the testis, epididymis, and epididymal sperm pellet with respect to control. Peroxidase and catalase activities in the sperm pellet were decreased significantly in comparison to the control. The results of this experiment indicate that fluoride at a dose encountered in drinking water in contaminated areas exerts an adverse effect on the male reproductive system and this effect is associated with indicators of oxidative stress.

Mimicking oxide surfaces: different types of defects and ligand coordination at well defined positions of a molybdenum oxide based nanocluster

The mixed valence cluster anion of the compound (NH4)32[MoVI110MoV28O416H6(H2O)58(CH3CO2)6].xH2O 1 (x approximately 250), synthesized under one-pot conditions, contains well-defined different types of defects--missing groups compared to the complete parent (Mo154) type cluster with full D7d symmetry--and acetate ligand coordination; this proves that the giant-wheel type anion can be considered as an object with a variety of nanoscale structural features ("nanostructured landscape") allowing reactions at a variety of well defined centers.

Effect of human chorionic gonadotrophin coadministration on ovarian steroidogenic and folliculogenic activities in cyclophosphamide treated albino rats

Quantitative evaluation of ovarian Delta5,3beta- hydroxysteroid dehydrogenese (HSD) and 17beta - HSD activities along with radioimmunoassay of plasma levels of gonadotrophins (FSH and LH), and estradiol (E2), and quantification of different types of developing follicles and regressive follicles were noted in mature rats of the Wistar strain following treatment with cyclophosphamide at a dose of 5 mg/kg body weight/day for 28 days. A significant reduction in plasma levels of LH and E2 along with significant diminution in the activities of ovarian Delta5,3beta -HSD and 17beta- HSD were observed following cyclophosphamide treatment for 28 days without any change in the plasma level of FSH. This treatment also produced a marked degree of degeneration in different types of follicles. Coadministration of hCG at 5 IU/kg body weight/day for 28 days in the cyclophosphamide-treated group provided significant protection except with respect to plasma LH. These results suggest the possibility of an indirect action of cyclophosphamide at the level of the ovary.

Sequence and analysis of chromosome 1 of the plant Arabidopsis thaliana

The genome of the flowering plant Arabidopsis thaliana has five chromosomes. Here we report the sequence of the largest, chromosome 1, in two contigs of around 14.2 and 14.6 megabases. The contigs extend from the telomeres to the centromeric borders, regions rich in transposons, retrotransposons and repetitive elements such as the 180-base-pair repeat. The chromosome represents 25% of the genome and contains about 6,850 open reading frames, 236 transfer RNAs (tRNAs) and 12 small nuclear RNAs. There are two clusters of tRNA genes at different places on the chromosome. One consists of 27 tRNA(Pro) genes and the other contains 27 tandem repeats of tRNA(Tyr)-tRNA(Tyr)-tRNA(Ser) genes. Chromosome 1 contains about 300 gene families with clustered duplications. There are also many repeat elements, representing 8% of the sequence.

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

[Relationship between nutritional composition and anatomical parameters in sorghum (Sorghum bicolor L. Moench)]

Nutritional and chemical parameters with significant differences (P = 0.5) among 10 varieties of sorghum and rates observed in them were as follow: lipids (2.76 to 3.75%), raw fiber (60.0 to 64.7%) protein (9.01 to 11.43%), no nitrogen extract 977.65 to 83.07%), starch (60.5 to 64.20%), tannin (2.50 to 10.16 mg/g), and total calories (380 to 4000 Kcal). Ash content with value of 1.17 to 1.91% protein digestibility (23.8 to 38.8%) and "in situ" starch (54.4 to 66.6%) were not statistically different. When correlation indexes were determined between results of chemical analysis, it was obtained follow positive correlation having significance: carbohydrates with total calories and fat with fiber. The main negative correlations were: fat and fiber with carbohydrates, fiber with calories, and digestibility "In vitro" of protein with tannin. In order to obtain equivalent analytical tests to substitute an anatomic determination for a chemical one, or vice versa, and make easy the selection of varieties for different use, and the adequate process for sorghum grain, were obtained correlations between chemical data of this study and compared to anatomic features determined in a previous analysis with same samples (1), it was found 19 significant coefficients from which 8 were positives and 11 negatives. The main correlations with capacity of analytical substitution were: size of starch grain of cornea endosperm-starch amount; size of protein body of flour-like endosperm-digestibility "in vitro" and "in situ" of protein; length of cell of flour like endosperm-starch amount; length and broad of aleurona cells-fiber content. The major negative correlations were: size of starch grain of cornea and flour-like endosperm ash; size of protein body of cornea endosper-starch amount; length and broad of aleurona cells-carbohydrates and total calories.